A concise review on the role of graphene in enhancing the electrochemical performances of alloy-type anodes in alkali metal ion batteries

Abstract

Alloy-type anode materials, including Si, Ge, Sn, Sb, P, and Bi, usually have high theoretical specific capacities for electrochemical alkali metal ion storage. However, they experience significant volume expansion/contraction during electrochemical alloying/dealloying with alkali metal ions, leading to poor cycling stability and low rate capabilities. As a result, various strategies have been proposed to suppress the volume variations and pulverization of alloy-type anode materials, such as incorporating them with carbonaceous materials. Graphene and its derivatives, with their ideal two-dimensional crystal morphology and unique chemical/physical properties, are often used as functional components to improve the electrochemical performance of alloy-type anode materials. This review emphasizes the recent research advances in alloy-type anode materials modified with graphene and its derivatives. It specifically covers the preparation methods, the structural and morphological characteristics, and the electrochemical performances of Sn/graphene, Sb/graphene, Ge/graphene, Bi/graphene, and P/graphene composites for alkali metal ion batteries. The ongoing developments in improving the electrochemical performance of alloy-type anodes with graphene are also speculated.

---

Qian Zhao

Qian Zhao is now studying for her doctorate at the School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University. She obtained her bachelor's degree from Xi’an University of Technology and her master's degree from Shaanxi University of Science & Technology. Her research interests are focused on energy storage materials, mainly including alloy-based anode materials for sodium-ion batteries.

Shouwu Guo

Shouwu Guo is a professor at the School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, P. R. China. He received his doctorate degree from Weizmann Institute of Science, Israel, in 1999. After working as a postdoctoral and research scientist at the University of Minnesota and Northwestern University, USA, he moved back to China at the end of 2005. His research interests are focused on graphene and low-dimensional nanomaterials, energy storage materials and devices, and biocatalysts.

---

1. Introduction

Alkali metal ion batteries (AMIBs), including lithium, sodium, and potassium ion batteries, usually exhibit higher charge/discharge cycling stability, operating potential, energy/power densities, and safety compared with other secondary batteries.^1–4 Conventional AMIBs consist of a cathode and an anode with appropriate current collectors, electrolytes, and separators.⁵ The cathode and anode materials are the key components dominating the overall electrochemical performance of AMIBs.^6–8 For lithium-ion batteries (LIBs), the layered LiCoO₂, the spinel structure LiMn₂O₄, the olivine LiFePO₄ and LiFe_1−xMn_xPO₄, and the layered LiCo_1−x−yNi_xM_yO₂ (M = Mn, Al) are often used as cathode materials.^9–12 The commercialized LIB anode materials are focused on artificial and natural graphite, whose market share reaches >97%.^13–15 As an anode material for LIBs, graphite has certain advantages, such as a low free energy for lithiation and delithiation, which makes the lithiation/delithiation highly reversible, the high electric conductivity, the favorable chemical inertia, and the abundant resource of raw material.^16,17 However, the relatively low specific capacity (372 mAh g⁻¹) for lithium ion storage limits its application in high-energy-density LIBs.¹⁸ The anisotropic layered crystal structure and limited d-spacing (0.335 nm) afford the graphite with poor Li⁺ diffusion coefficient that further restricts its application in high-power-density LIBs. On the other hand, with the development of electric vehicles (EVs) and other electric tools, LIBs with higher energy and power densities are urgently needed.^19–21 Therefore, exploring novel anode materials for LIBs is still attracting great attention in academic research and industry.

Besides, it is well known that the abundance of Li on the Earth is only about 0.06%, which is not sufficient to support the significant requirements of LIBs. For instance, the annual sales of LIBs in 2024 were ∼1545.1 GWh, consuming ∼1.37 × 10⁷ tons of Li.^22,23 Therefore, as alternatives to LIBs, other AMIBs, especially sodium ion batteries (NIBs) and potassium ion batteries (KIBs), have been extensively explored.^24,25 However, the developments of cathode and anode materials for NIBs and KIBs are far behind those of LIBs.^26–28 To date, there have been no appropriate cathode materials commercially available for NIBs and KIBs.^29,30 Because of the different ion radii of K⁺ (0.138 nm), Na⁺ (0.102 nm), and Li⁺ (0.076 nm), different redox potentials (vs. SHE) of K⁺ (−2.97 V), Na⁺ (−2.71 V), and Li⁺(−3.04 V), K⁺, Na⁺, and Li⁺ show different electrochemical reaction kinetics, and graphite shows lower specific capacities for K⁺ (∼280 mAh g⁻¹) and Na⁺ (<35 mAh g⁻¹) than that for Li⁺ (372 mAh g⁻¹).^31–33

To boost the energy densities of conventional LIBs and find appropriate anode materials for KIBs and NIBs, the alloy-type anode materials (AAMs), including Si, Ge, Sn, Sb, P, and Bi, have been explored, and they exhibit larger specific capacities for the alkali metal ion storages. For example, the theoretical specific capacities of Si, Ge, Sn, Sb, and P (red and black) for Li⁺ are 4200 (Li_4.4Si), 1624 (Li_4.4Ge), 990 (Li_4.4Sn,), 660 (Li₃Sb), and 2596 mAh g⁻¹ (Li₃P). Similarly, the theoretical specific capacities of Sn, Sb, and P (red) for Na⁺ and K⁺ storage can also reach 847 (Na_3.75Sn, K_3.75Sn,), 660 (Na₃Sb, K₃Sb), 2596 (Na₃P), and 1154 mAh g⁻¹ (K₃P₄).^34–38 However, the key issue for those AAMs is that the volume expansion/contraction during the electrochemical charging/discharging of the batteries is dramatic, some up to 200–300%. Due to the volume variation, it is difficult to form a stable solid electrolyte interface (SEI) layer on the AAM surface. The repeated formation/decomposition of the SEI consumes a large amount of electrolyte until it dries out. Meanwhile, the volume variation causes severe pulverization of AAMs, which detaches them from the current collector. Therefore, the batteries with bare Si, Ge, Sn, Sb, and P as anodes usually deliver poor charge/discharge cycling stabilities, which is a severe obstacle for practical applications. In addition, due to the low intrinsic electron/ion conductivities, the slow electrochemical reaction kinetics of the AAMs need to be improved, too.

During recent decades, many protocols have been proposed to suppress the volume variations and pulverization of the AAMs during electrochemical charging/discharging.^39–41 The main approaches include: (1) using nanosized and low-dimensional Si, Ge, Sn, Sb, and P, such as nanoparticles, nanowires, nanosheets, etc., (2) Creating enough nanoscaled physical compartments within the AAMs through physical and/or chemical procedures, and (3) using the composites of the Si, Ge, Sn, Sb, and P with other functional materials. Amongst them, the Si, Ge, Sn, Sb, and P coated with carbonaceous materials, including conductive carbon black, carbon nanotubes, and graphene and its derivatives, have been extensively explored. Graphene is an ideal two-dimensional (2D) crystal composed of carbon atoms that are bonded through sp² hybridization. The unique structure and morphology afford graphene with an ultra-large specific surface area of 2630 m² g⁻¹, Young's modulus of ∼1100 GPa, fracture strength of ∼125 GPa, thermal conductivity of ∼5000 W m⁻¹ K⁻¹, carrier mobility of ∼200 000 cm V⁻¹ s⁻¹, and visible light transmittance of ∼83%.^42–47 In comparison with pristine graphene, graphene oxide (GO), reduced graphene oxide (rGO), and the graphene doped with hetero elements usually contain different surface functionalities, and thus have been more frequently used as functional components to boost the electrochemical performances of AAMs.

Herein, we review the recent developments in AAMs modified with graphene and its derivatives, named AAM/graphene composites as anode materials. As aforementioned, Si, as an anode for LIBs, shows ultrahigh theoretical specific capacity (∼4200 mAh g⁻¹), but suffers the drawbacks of poor electron conductivity (10⁻³ S cm⁻¹) and severe volume variation during lithation/delithiation (300%).⁴⁸ During recent decades, many endeavors have been devoted to the design, fabrication, and electrochemical property evaluation of the composites of Si and graphene or rGO as anode materials in LIBs, and the related studies have been reviewed well, including two very recent review articles.^49,50 Due to the low alloying reaction kinetics of crystalline Si with Na and K, only amorphous Si is used as the active material in the anodes of NIBs and KIBs, but its Na⁺ and K⁺ storage capacities are much lower than that of Li⁺.^27,51–54 Accordingly, the composites of Si and graphene or rGO have barely been explored as anode materials in NIBs and KIBs. Therefore, this review covers mainly five parts: Sn/graphene, Sb/graphene, Ge/graphene, Bi/graphene, and P/graphene composites for AMIBs. In each section, the preparation method, the structural and morphological characteristics, and the electrochemical performances of the AAM/graphene composites are reviewed.

2. Sn/graphene composites for AMIBs

Tin (Sn) is one of the group IVA elements; the metallic Sn usually assumes a tetragonal crystal structure and exhibits marked electrical conductivity.^55–57 Although Sn is relatively chemically inert, it can form alloys with lithium, sodium, and potassium, M_xSn (M = Li, Na, K, 0.4 ≤ x ≤ 4.4).^58–60 As an AAM for AMIBs, the theoretical specific capacities of Sn for Li⁺, Na⁺, and K⁺ storage can reach 994, 847, and 226 mAh g⁻¹, respectively.^61–64 However, accompanied by a large specific capacity, Sn suffers from severe volume variation during alloying/dealloying with alkali metals, and the maximum volume expansion rates of Sn in LIBs, NIBs, and KIBs are 259%, 420%, and 300%, respectively, which severely affect the overall electrochemical performances, and even decidedly blocks the practical applications of Sn as an anode material in AMIBs.³⁵ Several review papers about Sn as anodes in AMIBs have been published recently;^65–68 herein, we will only highlight the recent progress on Sn/graphene composites as anodes in AMIBs.

2.1. Sn/graphene composites for LIBs

Early in 2009, a series of three-dimensional (3D) nanocomposites of nanosized Sn particles with graphene nanosheets (Fig. 1(a)) were designed and fabricated by Wang et al. As anode materials, the composites delivered higher electrochemical lithation/delithiation cycling stability over the bare Sn. The lithium storage capacity could be maintained at 508 mAh g⁻¹ after 100 lithiation/delithiation cycles (Fig. 1(b)).⁶⁹ Following that, composites of Sn nanoparticles and graphene sheets with different compositions and structural configurations were reported by several research groups, and all demonstrated that the electrochemical performances of Sn as an anode could be improved by graphene modification.^70–75 Differently, Zhang et al. prepared a 3D foothill-like graphene scaffold on Ni foil, and then deposited Sn nanoparticles on the graphene sheets, and the composites, as an anode for LIBs, delivered a reversible capacity of 466 mAh g⁻¹ at a current density of 879 mA g⁻¹ (1C) after over 4000 cycles,⁷⁶ which are much better than those of the aforementioned composites prepared simply using graphene and Sn nanoparticles. The anode for LIBs using graphene sheets anchored with Sn nanoparticles (Sn/GS) obtained through an in situ solvothermal procedure showed a notable specific capacity for Li ion storage, but the poor initial coulombic efficiency (ICE) remained to be improved.⁷⁷

Fig. 1 (a) FESEM image of a Sn/graphene nanocomposite. (b) Reversible lithium storage capacity vs. cycle number for the Sn/graphene nanocomposite, bare graphene electrode, and bare Sn as an anode.⁶⁹ Copyright 1991 Royal Society of Chemistry.

Due to the chemical affinity of nitrogen-containing groups to metal and metal ions, the unique electrochemical properties of graphene sheets doped with nitrogen (N-doped graphene), along with ions, have led to the preparation and use of Sn nanoparticle composites with N-doped graphene as anodes in LIBs.^79,80 For example, the composites of Sn nanoparticles with N-doped rGO (Sn/N-rGO) could be produced through heat treatment of the composites of SnO₂ nanocrystals and N-doped rGO⁷⁸ (Fig. 2(a) and (b)). The Sn/N-rGO showed a reversible capacity of 481 mAh g⁻¹ after 100 cycles under 0.1 A g⁻¹, and a charge capacity as high as 307 mAh g⁻¹ under a relatively higher current density of 2 A g⁻¹ (Fig. 2(c) and (d)). Besides the N-doped graphene, the hierarchical porous composites of sulfur-doped graphene and nanosized Sn (Sn/3DSG) also showed a large lithium ion storage capacity and a higher lithiation/delithiation rate capability than those using graphene sheets.⁸¹

Fig. 2 (a) and (b) SEM and high-magnification SEM images of Sn/N-rGO. (c) and (d) Lithiation/delithiation cycling performance and rate capability of the Sn/N-rGO anode.⁷⁸ Copyright 2013 American Chemical Society.

Besides spherical Sn nanoparticles, composites of Sn nanosheets and nanorods with graphene have also been explored as anode materials for LIBs. For example, graphene-confined Sn nanosheets (G/Sn/G), with thicknesses of about 10 nm for Sn nanosheets and 5 nm for graphene sheets, were studied. It was shown that the 2D sheet morphology of Sn and the elasticity of graphene sheets could accommodate the volume variation of Sn during the lithiation/delithiation, and the reversible capacity of this type of composite for lithium ion storage remained at ∼590 mAh g⁻¹ after 60 cycles.⁸² The Sn nanorods coated with graphene (Fig. 3(a) and (b)) also exhibited better electrochemical properties for Li⁺ storage than those of carbon coated Sn (Fig. 3(c) and (d)). Additionally these composites demonstrated excellent thermal and chemical stabilities.⁸³

Fig. 3 (a) TEM image of Sn/G nanorods with diameters of 40–60 nm and lengths of 400–2000 nm. (b) STEM-EDS mapping of an individual nanorod of Sn/G. (c) Cycling performance of Sn/G, Sn/C, and pure metallic Sn electrodes at a current density of 200 mA g⁻¹ between 0.05 V and 3 V. (d) Rate performance of Sn/G and Sn/C electrodes at rates of 0.2, 0.5, 1, and 2C.⁸³ Copyright 2011 Royal Society of Chemistry.

More complex nanoarchitectures have also been designed and fabricated using nanoscale Sn particles and graphene sheets as building blocks, and have been utilized as anodes in LIBs.^80–86 For example, Sn/carbon coaxial nanocables were grown directly onto the rGO surface using a CVD (chemical vapor deposition) process, and the resulting nanoarchitectures demonstrated excellent lithium storage performance.⁸⁴ Even more impressively, using an in situ CVD technique, and with the 3D self-assembled NaCl particles as a template, 3D porous graphene networks anchored with Sn nanoparticles (5–30 nm) encapsulated in graphene shells with about 1 nm thickness (Sn/G-PGNWs) were obtained. It was shown that the graphene shells could prevent Sn nanoparticles from direct contact with the electrolyte, maintain the stability of the structure and interfaces, suppress the aggregation of Sn nanoparticles, buffer volume expansion, enhance electrical conductivity, and thus give the Sn/G-PGNWs excellent electrochemical properties as anodes in LIBs (Fig. 4).⁸⁵

Fig. 4 (a) and (b) TEM images of 3D Sn/G-PGNWs. (c) and (d) TEM images of the walls of porous graphene networks. (e) and (f) HRTEM images and (g) STEM image of Sn/G nanoparticles. (h) Cross-sectional EDX elemental mapping of point 1 in (g).⁸⁵ Copyright 2014 American Chemical Society.

Meanwhile, the underlying mechanisms of how graphene sheets influence the electrochemical performances of the Sn anode were investigated.^77,86–88 L. Niu et al. compared the electrochemical properties of Sn nanoparticles anchored on partially reduced graphene oxide (Sn–O–G) and a fully reduced one (Sn–G), demonstrating that the Sn–O–C bonds between Sn nanoparticles and graphene were a key factor in enhancing the Li-storage properties of the composites.⁸⁹ The lithium storage performance of Sn/graphene composite was also examined using quantum chemical calculations based on density functional theory, revealing that the higher electronic conductivity of Sn/graphene over that of Sn metal could partially explain its superior lithium storage performance.⁸⁶ Additionally, the alignment of graphene sheets within the Sn/graphene composite on the surface current collector was found to be crucial for the electrochemical performance of the composite, too.⁸⁸

2.2. Sn/graphene composites for NIBs and KIBs

In comparison, the developments of NIBs and KIBs in fundamental research and commercialization fall far behind those of the LIBs.^90,91 The intrinsic chemical/physical properties of Li⁺, Na⁺, and K⁺, such as the ionic radius, ion diffusion coefficient, and redox potentials, may account partially for the difference. The lack of appropriate cathode and anode materials for NIBs and KIBs can be another factor.^92,93 For example, the widely used graphitic anode materials show low Na⁺ ion storage capacity and poor electrochemical potassiation/depotassiation kinetics.^94–96 However, similar to Li, Na and K can alloy with Sn, forming Na₁₅Sn₄ and K₄Sn₉;^61,97 thus, metallic Sn has been studied as an alloy-type anode for NIB and KIB.^{57,61,64,98–102} We will review the recent progress of the effects of graphene incorporation on the electrochemical properties of the Sn anodes of NIBs and KIBs.

To improve the sodiation/desodiation cycling stability of Sn, a simple camera flash (light) reduction procedure was developed by Paik et al. A porous scaffold composed of both rGO and graphene (nrGO/G) was prepared first, then Sn nanoparticles were loaded within the porous nrGO/G through an electrophoretic deposition method (Fig. 5(a)–(c)). The freestanding Sn-coated (SnrGO/G) films as an anode showed marked sodiation/desodiation behaviors, the reversible Na ion storage capacity reached 615 mAh g⁻¹ with excellent rate capability, and also tunable mechanical strength, which should be beneficial for the practical application of this type of anode material (Fig. 5(d) and (e)).¹⁰³

Fig. 5 (a) Schematic illustration of the fabrication process of Sn-coated nrGO/G films (n: the ratio of rGO to graphene). (b) TEM image, and (c) high-resolution TEM image of Sn-coated 2rGO/G. (d) Sodiation/desodiation voltage profiles during the 1st and 2nd cycles of the Sn-coated 2rGO/G film as an anode at a rate of 0.5C, and (e) the rate capabilities of Sn-coated 2rGO/G film as an anode at various C rates from 0.05C to 20C, compared with those of the Sn-coated 1rGO/G film.¹⁰³ Copyright 2016 Royal Society of Chemistry.

Z. Fan and collaborators prepared N-doped graphene quantum dots (GQDs) edge-anchored with Sn nanodots (NGQD/Sn), and then embedded them as the pillars into rGO matrices, obtaining ternary composites of NGQD/Sn-NG (Fig. 6). The procedure seemed a little bit complicated; the authors claimed that the GQD pillars ensured the fast diffusion of Na⁺ and electrons crossing the graphene blocks, and the rGO matrices not only blocked the Sn aggregation, but also buffered the volume change upon sodiation/desodiation.¹⁰²

Fig. 6 Schematic illustration of the fabrication process for the graphene quantum dot edge-anchored Sn nanodot pillared graphene matrices (NGQD/Sn-NG). Carbon, nitrogen, and oxygen are represented by gray-, blue-, and red-colored spheres, respectively.¹⁰² Copyright 2020 John Wiley and Sons.

Considering the limited natural resources of Sn, to maximize the use of Sn in the composite for sodium ion storage is essential. A series of free-standing B₄C/Sn/acetylene black/rGO (B₄C/Sn/AB/rGO) films were designed and prepared, in which the B₄C coated on the Sn served as a conductor, acetylene black on B₄C/Sn could enhance the electrolyte solution affinity, and rGO accelerated the charge carrier transportation and alleviated the volume expansion during the sodiation/desodiation.¹⁰⁴ With this type of structure, the free-standing film containing 2.9% (atomic ratio) of Sn delivered a high reversible capacity of 393.4 mAh g⁻¹ at 0.1 A g⁻¹. It was also reported that fully encapsulating Sn with graphene or other carbonaceous materials was key to the electrochemical performance of the Sn anode. In a proof-of-concept, carbon-coated Sn/rGO (Sn/rGO/C) composites were prepared through supercritical methanol, followed by a high-pressure free meniscus coating and carbon thermal reduction procedure. The Sn/rGO/C as anodes in both half-coin cell and full cell NIBs showed relatively larger specific capacity, and good cycling stability.¹⁰¹

The Sn/graphene composites usually showed higher gravimetric capacity, but lower volumetric capacity. To boost its volumetric capacity, a Sn-pillared pyknotic graphene conductive network with high-content N-doping was developed, and it was found that the pyknotic graphene network afforded the composites with attractive volumetric capacity for Na ions (Fig. 7).¹⁰⁵

Fig. 7 (a)–(c) SEM images of the Sn-pillared pyknotic graphene conductive network with high-level N-doping (Sn/P-NGB). (d) Gravimetric/volumetric capacity of Sn-P-NGB at different rates, and (e) corresponding cycling stability at 0.1 A g⁻¹.¹⁰⁵ Copyright 2022 American Chemical Society.

In contrast to the specific capacity for Li⁺ and Na⁺, the Sn anode shows a relatively low specific capacity for K⁺ storage, and the volume variation and pulverization are still drawbacks for the practical application of bare Sn as an anode in KIBs.^97,106,107 Besides the composites of Sn with an amorphous carbon matrix,¹⁰⁷ the sub-micrometer-sized Sn particles encapsulated uniformly within the rGO network (Sn/rGO) were fabricated. The results showed that, except for the low initial Coulombic efficiency (ICE) at a current density of 100 mA g⁻¹, the specific capacity for K⁺ storage was 200 mAh g⁻¹; after 500 potassiation/depotassiation cycles at a current density of 500 mA g⁻¹, the capacity remained at 123.6 mAh g⁻¹.¹⁰⁸ The study implied that incorporating Sn nanoparticles within the graphene matrix is one way to improve the electrochemical properties of Sn as an anode in KIBs, but more fundamental research is still needed. Nevertheless, the current studies reviewed here suggested that the confinement-based synthesis together with remarkable electrochemical performances shed light on the practical application of Sn/graphene anodes for next-generation AMIBs.

3. Sb/graphene composites for AMIBs

Antimony (Sb) is located in the same period as Sn and is nearby in the main group. Similar to Sn, Sb can react electrochemically with Li⁺, Na⁺, and K⁺, forming a variety of alloys, and thus has great promise as an anode material for AMIBs, but faces similar drawbacks to Sn anodes.^109,110 This section will cover the recent progress on the fabrication and electrochemical performances of Sb/graphene composites as anodes in AMIBs.

3.1. Sb/graphene composites for LIBs

Early in 2014, J. Xie et al. prepared sheet-like composites of Sb nanocrystals (50–100 nm) loaded on few-layered rGO sheets simply through a solvothermal procedure using SbCl₃ and GO as the precursors, and NaBH₄ as the reductant.¹¹¹ However, it was found that the ICE and the lithiation/delithiation cycling stability of the composites as anodes for LIBs were unacceptably low. Afterward, composites of Sb/graphene with different morphologies and compositions were examined by others, but the ICE and the lithiation/delithiation cycling stability are still problems.¹¹² To overcome the obstacles, X. Zhou et al. found that by controlling the oxygen-containing groups on the rGO, the lithiation/delithiation cycling stability of Sb/rGO could be improved.¹¹³

Meanwhile, Sb thin film sandwiched between rGO and Ni foam (rGO/Sb_TF–Ni) was fabricated through a galvanic replacement reaction followed by pulse electrophoretic deposition, in which the contents of rGO and Sb are about 2.5% and 6.35% (in weight), respectively (Fig. 8(a)–(c)).¹¹⁴ As a binder-free anode material for LIBs, the rGO/Sb_TF–Ni had a large Li⁺ storage capacity of 872.9 mAh g⁻¹ and an enhanced ICE of 66.0% at a current density of 100 mA g⁻¹ (Fig. 8(d) and (e)). This work demonstrated that the unique hierarchical sandwich architectures assumed excellent electrical contact, and the flexible rGO and Ni foam together had a decent buffer effect to alleviate the large volume change during lithiation/delithiation.

Fig. 8 (a) Schematic illustration of the synthesis route for the rGO/Sb_TF–Ni composite. (b) SEM images of the rGO/Sb_TF–Ni composite. (c) SEM image and element mappings of the rGO/Sb_TF–Ni composite. (d) Voltage–capacity curves of rGO/Sb_TF–Ni as an anode in LIBs. (e) Galvanostatic lithiation/delithiation cycling performances of rGO/Sb_TF–Ni.¹¹⁴ Copyright 2016 Elsevier.

More recently, a ternary composite containing nanosized Sb, rGO sheets, and N,S co-doped carbon, abbreviated as Sb/rGO/NSC, was proposed.¹¹⁵ The electrochemical measurements showed that, with an appropriate N, S co-doping dose, the 3D hierarchical porous structured Sb/rGO/NSC-0.3 had a Li⁺ storage capacity of 1121.2 mAh g⁻¹ at a current density of 0.5 A g⁻¹ over 500 cycles, but the ICE remained low.

3.2. Sb/graphene composites for NIBs and KIBs

Differing from that in LIBs, it has been elaborated that the intermediate products of the sodiation of Sb usually showed amorphous phases, and the crystalline Na₃Sb was not formed until the very end of the sodiation. Nevertheless, as anodes in NIBs, pure micrometric Sb can deliver a Na⁺ storage capacity of ∼600 mAh g⁻¹ at 0.5C with a coulombic efficiency of 99% over 160 cycles (Fig. 9).¹¹⁶ Therefore, more work has been conducted on the Sb-based anode materials for NIBs and KIBs over LIBs, including the composites of Sb/graphene.

Fig. 9 (a) Selected operando XRD patterns at various stages of discharge and charge of a Sb/Na cell. * and ¤ indicate the Bragg peaks corresponding to Sb and Na₃Sb, respectively. (b) Rate capability (and polarization, inset) of the Sb electrode at various current rates from 0.1 to 4C. Open and filled symbols are for discharge and charge, respectively.¹¹⁶ Copyright 2012 American Chemical Society.

Generally, Sb shows marked Na⁺ storage capacity, but the rate capability and cycling stability are not satisfactory for practical applications as an anode in NIBs. Early in 2015, X. Zhou et al. developed a confined vapor deposition method and chemically coupled Sb onto multilayered graphene sheets, generating Sb/multilayered graphene composites, and illustrated that the Sb/multilayer graphene composite had a long-term cycling performance with 90% capacity retention after 200 cycles, and good rate capability (210 mAh g⁻¹ under 5000 mA g⁻¹) (Fig. 10).¹¹⁷ Following that, different protocols have been proposed to prepare the binary composites of Sb/graphene or rGO as anodes in NIBs, including an in situ reduction process,^118–121 the conversion of Sb₂O₃/GO to Sb/rGO with an electro-deoxidation approach,¹²² electrochemical cathodic corrosion,¹²³ the room temperature solid state reaction procedure,¹²⁴ and ball-milling combined with pyrolysis treatment.¹²⁵ These studies generally illustrated that the graphene or rGO sheets could enhance the charge carriers’ (Na⁺ and electrons) transportation, stabilizing the SEI films upon the Sb volume changes during cycling.¹²⁶ However, the deficiency of efficient and scalable preparation approaches of high-performance nanosized Sb and its composites remains challenging.

Fig. 10 (a) Schematic illustration of the preparation process for the Sb/multilayered graphene composites. (b) Cycling performance of the multilayered graphene, Sb, mixture of Sb and multilayered graphene, and Sb/multilayered graphene composite as an anode in NIBs. (c) Rate capability of the multilayered graphene, Sb, mixture of Sb and multilayered graphene, and Sb/multilayered graphene composite.¹¹⁷ Copyright 2015 American Chemical Society.

Meanwhile, ternary composites containing Sb, graphene, and other components were proposed to further enhance the electrochemical performances of Sb as an anode in NIBs. To mention a few, composites of porous graphene anchored with Sb/SbO_x (Sb/SbO_x/graphene) were prepared by D. Li et al., and they found that as anodes in NIBs the electrochemical performances of this type of the ternary Sb/SbO_x/graphene composites were better than those of Sb/graphene and SbO_x/graphene, however, the underneath mechanisms remain unclear.¹²⁷ Combining electrospinning and electrospray processes, antimony–carbon–graphene (Sb/C/G) fibrous composites were successfully fabricated, and as a freestanding anode in NIBs the Sb/C/Gs exhibited a larger capacity for Na⁺ storage over the Sb/C fibers, but the ICE was a big problem for those composites.¹²⁸ Similarly, a spherical Sb nanoparticle-embedded carbon/rGO composite containing voids was also prepared, but the poor ICE was the drawback, too.¹²⁹ In contrast, a carbon coated graphene/Sb composite (G/Sb/C) with a unique sandwich-like structure as anodes in NIBs delivered a reversible capacity of 569.5 mAh g⁻¹ after 200 cycles at a current rate of 0.1 A g⁻¹, and the coulombic efficiency was ∼99% (Fig. 11).¹³⁰ The unique electrochemical performances of the sandwich-like structured Sb composites, such as graphene/Sb/graphene, were investigated theoretically by J. Su et al., who illustrated that the sandwich-like G/Sb/G had superior thermodynamic stability, good electronic conductivity, and ultrahigh stiffness, which greatly suppressed the structural destruction of the Sb during the sodiation/desodiation processes.¹³¹ The advantages of using a sandwich-like structure or even layer-by-layer structure with Sb and graphene composites as anodes in NIBs were also illustrated in the laboratories of other research groups. As shown in Fig. 12, with the layer-stacked Sb/graphene micro/nanocomposites (LS-Sb/G) as anodes, the full-cell NIB, LS-Sb/G//NVP (Na₃V₂(PO₄)₃), delivered a reversible capacity of 116.5 mAh g⁻¹ at 0.1C.¹³² Besides, the full cell NIBs (NVP/rGO//Sb/rGO) assembled using Sb/rGO as anodes and NVP/rGO as cathodes showed an even higher reversible capacity of ∼400 mAh g⁻¹ at a current density of 100 mA g⁻¹ after 100 charge/discharge cycles, implying that the rGO could also improve the electrochemical properties of the NVP.¹³³

Fig. 11 SEM images of G/Sb (a) and (b), G/Sb/C (c) and (d), and Sb particles (e) and (f). (g) CV curves of the G/Sb/C electrode from 2.0 to 0.01 V vs. Na/Na⁺ at a scan rate of 0.1 mV s⁻¹. (h) Charge/discharge profiles of the G/Sb/C electrode at a current rate of 0.1 A g⁻¹ between 2.0 and 0.01 V for the 1st, 2nd, 3rd, 10th, 50th, and 100th cycles. (i) Cycling performances of G/Sb/C, G/Sb, and Sb electrodes at a current rate of 0.1 A g⁻¹. (j) Rate capacities of G/Sb/C, G/Sb, and Sb electrodes at current rates from 0.1 to 5.0 A g⁻¹.¹³⁰ Copyright 2017 Royal Society of Chemistry.

Fig. 12 (a) Schematic presentation of the evolution of layer-stacked LS-Sb/G at different solvothermal reaction times for 3 h, 6 h, 9 h, and 24 h. (b)–(e) Corresponding SEM images at different reaction times. (f) and (g) The rate performance and the corresponding galvanostatic charge/discharge performances voltage profiles, respectively, of LS-Sb/G//NVP full cells between 1.2 and 3.8 V at different rates from 0.1 to 0.5C.¹³² Copyright 2018 Elsevier.

As described above, in most cases, the composites of Sb/graphene or Sb/rGO were prepared by coating the graphene or rGO sheets on the surface of Sb particles. More recently, the faceted crystalline Sb particles with the interiors reinforced with rGO were designed and fabricated (Fig. 13(a)).¹³⁴ The as-obtained Sb/rGO composites as anode materials in NIBs could deliver a reversible Na⁺ storage capacity of ∼550 mAh g⁻¹ at a current density of 0.2 A g⁻¹ and a manifest ICE of ∼79% (Fig. 13(b)–(d)). The results demonstrated that the unique interior-reinforced configuration, the coarse particle size of Sb, and the encapsulation of rGO sheets inside the Sb particles were the key factors accounting for the good electrochemical performances of the composites.

Fig. 13 (a) SEM image of the faceted crystalline Sb particles with the interiors reinforced with rGO. (b) Variations of the specific Na-storage capacities and Coulombic efficiencies, with cycle number, during galvanostatic cycling of the faceted crystalline Sb particles with the interiors reinforced with rGO at a current density of 0.2 A/g. (c) Variations of reversible Na-storage capacities with current densities during continuous galvanostatic cycling runs (i.e., rate capability). (d) Representative potential profiles obtained during galvanostatic cycling at the different current densities.¹³⁴ Copyright 2022 American Chemical Society.

In practice, the additives, including binder and conducting reagents, can also affect the electrochemical properties of Sb/graphene and Sb/rGO composites as anodes. For instance, using carboxymethylcellulose (CMC) as a binder, the Sb/rGO anode could deliver a high capacity of ∼400 mAh g⁻¹ at a high current density of ∼30C.¹³⁵

Sb and Sb-based materials have been explored more extensively as the anode materials in KIBs than those in LIBs and NIBs.^136,137 Here, we mainly focus on the recent work on the composites of Sb with graphene or rGO for KIBs. Early in 2015, O. Lev et al. fabricated composites of Sb/SbO_x and graphene oxide (Sb/SbO_x/GO) through a peroxide deposition route, and studied the electrochemical performance for K⁺ storage. They found that besides the ICE, the Sb/SbO_x/GO as anodes delivered superior potassiation/depatassiation rate capability and cycling stability over the bare Sb metal.¹³⁸ In fact, other binary composites of nanosized Sb and rGO reported so far also exhibited superior electrochemical performances over bare Sb as an anode.^139,140

A series of ternary composites containing rGO, amorphous carbon, and Sb nanoparticles (Sb/C/rGO) were explored as anodes in KIBs. It had been demonstrated that the amorphous carbon layer coated on the surface of Sb nanoparticles could protect Sb pulverization, the rGO sheets buffered the volume variation of Sb during the potassiation/depotassiation and enhanced the conductivity of the composites. The Sb/C/rGO showed a capacity of 550 mAh g⁻¹ at 100 mA g⁻¹, a rate capability of 370 mAh g⁻¹ at 2000 mA g⁻¹, and a lifespan of 350 cycles without significant capacity fading (Fig. 14).¹⁴¹ At the same time, a similar ternary composite (Sb/C/rGO) with unique microspherical morphology was reported (Fig. 15(a)), which as anodes for KIBs showed a reversible capacity of 310 mAh g⁻¹ at 0.5 A g⁻¹, but with a poor ICE (Fig. 15(b)). The main reason was attributed to the side reaction of K metal with the electrolyte, forming a metastable phase of K_xSb.¹⁴²

Fig. 14 (a) Cycle performance of Sb/C/rGO at a current density of 100 mA g⁻¹. (b) Rate performance of Sb/C/rGO at various current densities from 0.1 to 3 A g⁻¹. (c) Cycle performance of Sb/C/rGO at a current density of 500 mA g⁻¹.¹⁴¹ Copyright 2020 John Wiley and Sons.

Fig. 15 (a) TEM images of the Sb/C/rGO microspheres. (b) Discharge/charge profiles of Sb/C/rGO microspheres.¹⁴² Copyright 2019 American Chemical Society.

4. Ge/graphene composites for AMIBs

The abundance of germanium (Ge) in the Earth's crust is ∼1.5 × 10⁻⁴% (∼1.5 ppm).¹⁴³ The scarcity and high cost of Ge should hinder undoubtedly its practical applications as an anode in AMIBs. However, the theoretical specific capacity of Ge for Li⁺ storage is about 1384 mAh g⁻¹ (8334 mAh cm⁻³) once forming Li₁₅Ge₄.¹⁴⁴ Therefore, Ge and its derivatives have been frequently explored as anode materials in AMIBs. There are several review articles documenting the Ge as anodes, and interested readers are directed to the references.^143–148 Having a bandgap width of 0.66 eV, narrower than that of Si (1.12 eV), the Ge-based anodes exhibit better electronic conductivity than Si anodes. For example, the lithium ion diffusion coefficient in Ge is approximately 400 times that in Si at room temperature.¹⁴⁹ The alloying of Ge with alkali metals is through an isotropic mechanism (Si is through an anisotropic mechanism), which can alleviate the volume expansion to some extent, but still does not meet practical applications.¹⁴⁹ Therefore, as summarized below, the composites of Ge, mostly Ge/graphene or Ge/rGO, have been widely studied as the active anode materials in AMIBs in recent years.

4.1. Ge/graphene composites for LIBs

To improve the poor cycling stability and increase the utilization rate of Ge anodes in LIBs, Ge/graphene nanocomposites were prepared through a low-pressure thermal evaporation approach by S. Lee at al. Besides a high reversible Li⁺ storage capacity, the electrochemical measurement showed that the utilization rate of Ge was 92.2%, and the ICE reached 80.4%.¹⁵⁰ Ge/rGO binary composites with similar morphologies prepared using different techniques were also explored as LIB anodes.^151,152 Notably, the Ge/graphene binary composite on Ni substrate as anode materials delivered extremely high rate capabilities.¹⁵³ Recently, Ge nanoparticles were uniformly immobilized on 3D interconnected porous graphene frameworks (Ge/3DPG composites) through a template-assisted in situ reduction method, and the electrochemical performances of the composites as anodes both in half and full cell LIBs were evaluated. It was found that the 3D interconnected porous graphene could enhance the electronic conductivity and buffer the volume expansion of Ge during lithiation/delithiation, thus affording the composite with a large reversible specific capacity and high rate capability (Fig. 16).¹⁵⁴

Fig. 16 (a) and (b) TEM images of the Ge/3DPG composite. (c) Schematic diagram of the lithium alloying/dealloying with Ge/3DPG during repeated cycles. (d)–(f) Full battery performances of Ge/3DPG//LiFePO₄, and (d) charge/discharge profiles for the first five cycles under the current density of 0.1C (1C = 170 mA g⁻¹). (e) Long-term cycling performance at 0.5C, and (f) rate capability at various current densities of 0.1–5C.¹⁵⁴ Copyright 2022 Elsevier.

Similar to Si, Sn, and Sb anodes, the N-doped graphene or N-rGO matrix affords Ge anodes with a better electrochemical performance than that of graphene and rGO. Ge/N-rGO composites prepared through a wet chemistry procedure in the presence of polyvinylpyrrolidone (PVP) showed improved specific capacity and rate capability for Li⁺ storage, but with a low ICE.¹⁵⁵ An anode prepared with Ge quantum dots embedded in N-rGO with a sponge-like feature, fabricated through freeze-drying of the mixture of Ge(OH)₄ and GO in ethanol, followed by reduction in H₂ gas, showed a higher ICE.¹⁵⁶ The reduced size of Ge quantum dots and the unique sponge-like morphology of the N-rGO may contribute to its performance.¹⁵⁶ Similarly, a 3D interconnected porous nitrogen-doped graphene (NG) foam with encapsulated Ge quantum dot/NG graphene yolk–shell nanoarchitecture was prepared and employed as a flexible anode for LIB (Fig. 17(a)–(f)), and the volume variations of Ge during lithiation/delithiation was suppressed maximally due to the unique hierarchical structure. As a result, the composite showed high specific reversible capacity (1220 mAh g⁻¹), long cycling capability (over 96% reversible capacity retention from the second to 1000 cycles), and ultra-high rate performance (over 800 mAh g⁻¹ at 40 °C) (Fig. 17(g) and (h)).¹⁵⁷ This work paved the way to high-performance flexible LIBs with Ge-based anodes. However, the detailed mechanism of how the as-doped N affects the electrochemical properties of the composites remains unknown.

Fig. 17 (a) SEM, and (b) and (c) TEM images of the Ge-QD/NG/NGF/PDMS yolk–shell electrode before lithiation/delithiation. (d) SEM, and (e) and (f) TEM images of the Ge-QD/NG/NGF/PDMS yolk–shell electrode in a lithium intercalation state after 1000 cycles at a current density of 1C, showing the robust structure of the composite. (g) Galvanostatic charge–discharge profiles in the 0.01–1.5 V window (versus Li/Li⁺) for the 1st, 2nd, 10th, 100th and 1000th cycles at 1C. (h) Cycling performance (discharge) and coulombic efficiency of the Ge-QD/NG/NGF/PDMS yolk–shell electrode, Ge/NGF/PDMS [poly (dimethyl siloxane)] and Ge/Cu electrodes at 1C for 1000 cycles.¹⁵⁷ Copyright 2017 Nature.

By adjusting the ratio of rGO to Ge and the size of Ge particles, the graphene-encapsulated Ge nanowires (Ge/G) were fabricated with an arc-discharge technique,¹⁵⁸ and the nanofibers of the mixture of Ge and rGO (Ge/RGO NFs) were prepared through electrospinning.^158,159 These materials could deliver large Li⁺ storage specific capacities (close to the theoretical capacity of Ge), high rate capabilities, long cycling stability, but poor ICE. To obtain Ge/rGO composites with a more robust structure against the volume variation of Ge, a lot of ternary composites with a sandwich-like structure were designed and fabricated as the anode materials. For instance, Ge nanoparticles coated with a thin carbon layer on rGO sheets (C/Ge/rGO),¹⁶⁰ Ge nanoparticles on rGO (Ge/rGO) intertwined with carbon nanotubes (CNT/Ge/rGO),¹⁶¹ Ge nanoparticles coated with rGO on vertically aligned graphene sheets (rGO/Ge/graphene),¹⁶² and rGO/Ge/rGO composites.¹⁶³

These composites with sandwich-like structures showed overall better electrochemical performances for Li⁺ storage, because the Ge nanoparticles were fully wrapped with rGO and carbonaceous materials. For example, the coin-type full cell composed of the rGO/Ge/rGO anodes and the NCM523 (LiNi_0.5Co_0.2Mn_0.3O₂) cathode showed a specific capacity of 940 mAh g⁻¹ with a capacity retention of 93.6% after 100 cycles at a rate of 1C (Fig. 18).¹⁶³

Fig. 18 Electrochemical performance of coin-type full cells containing a rGO/Ge/rGO anode and an LiNi_0.5Co_0.2Mn_0.3O₂ cathode within the cut-off voltages of 2.0–4.0 V. (a) Cycling performance at 1C rate and coulombic efficiency (inset). (b) Rate capability of the full cell.¹⁶³ Copyright 2017 Royal Society of Chemistry.

More recently, a thin layer of amorphous Ge was deposited onto 3D graphene networks on Ni foam using a CVD technique via radio frequency magnetron sputtering and as an anode, the as-obtained materials showed better lithiation/delithiation cycling stability than other Ge/graphene or rGO composites.¹⁶⁴ Differently, Ge-based glass modified with graphene through a ball-milling technique was also tested as anodes in LIBs,¹⁶⁵ the electrochemical properties of this type of glass-state material, especially the ICE, seemed unsatisfactory for practical applications, yet it opened a way to scalable production of the Ge/graphene-based anode materials. Yue et al. studied the relationships among the composition, structure and electrochemical properties of composites of 3D graphene with Ge through first-principles calculations, and pointed out that the high adsorption energy of graphene to Ge is beneficial to the lithium-ion storage performance and cycling life of Ge anodes.¹⁶⁶

4.2. Ge/graphene composites for NIBs and KIBs

Ge can electrochemically alloy with Na and K, and is useful as an anode for NIBs and KIBs as well. However, the low Na and K content of the NaGe and KGe alloys results in a theoretical specific capacity of ∼369 mAh g⁻¹ for Na⁺ and K⁺ storage, which is far below 1384 mAh g⁻¹ for Li⁺ storage. Only few studies of Ge as an anode material in NIBs or KIBs have been reported.^{144,167–169} Wang et al. reported Ge/G/TiO₂ NFs prepared through electrospinning and atomic layer deposition, and investigated their electrochemical performances as anodes in NIBs. With the dual protections from graphene and TiO₂, Ge/G/TiO₂ delivered a specific Na⁺ storage capacity of 194 mAh g⁻¹ after 100 cycles, better than bare Ge.¹⁷⁰

5. Bi/graphene composites for AMIBs

Bi has a layered structure similar to graphite, and the interplanar spacing is 0.395 nm, but it undergoes an electrochemical alloying mechanism for alkali metal ion storage.¹⁷¹ In comparison to Si, Sn, Sb, and Ge, which exhibit remarkable Li⁺ storage capabilities, the advantages of Bi as an anode in LIBs seem less prominent.^172,173 There are a few studies of the Bi/graphene or rGO composites as an anode in LIBs.¹⁷⁴

Bi as an anode in NIBs or KIBs usually exhibits a higher volumetric theoretical capacity (∼3800 mAh cm⁻³), but relatively lower gravimetric theoretical capacity (∼385 mAh g⁻¹), and thus has promise for the fabrication of compact NIBs or KIBs.^{171,175–178} The relatively high voltage plateaus for the electrochemical alloying reaction of Bi with Na or K (0.3–0.5 V vs. K⁺/K) ensure the safety of NIBs and KIBs. Unfortunately, the volume variation, pulverization, formation/decomposition of SEI films, low coulombic efficiency during sodiation/desodiation, and potassiation/depotassiation of Bi remain to be addressed.

The composites of Bi and graphene or rGO with different compositions and morphologies have been designed and fabricated, and their electrochemical performances have been evaluated. For instance, J. Kim et al. prepared the first Bi/rGO composites with the sizes of Bi from 10 to 950 nm in diameter by a supercritical acetone technique. They studied the electrochemical Na⁺ storage properties of the Bi/rGO with those of bare Bi and Bi₂O₃/rGO in parallel. The Bi/rGO could deliver a reversible gravimetric capacity of 200 mAh g⁻¹ at 50 mA g⁻¹ and a high volumetric capacity of 60 000 mAh L⁻¹, better than those of bare Bi and Bi₂O₃/rGO. It was illustrated that the sodiation/desodiation kinetics depended strongly on the Bi particle size.¹⁷⁹ Meanwhile, the electrochemical properties of the composites of microsized Bi and graphene with different Bi to graphene ratios were also studied, and they found that the gravimetric and volumetric performances could be modulated by tuning the ratio of Bi to graphene (Fig. 19).¹⁸⁰ In addition, many efforts were devoted to improving the structural integrity of the composites of Bi and graphene or rGO to further enhance their cycling stability. For example, Bi was successfully loaded on rGO with strong Bi–O–C bonding through an electrochemical reduction of GO together with Zintl cluster Bi₂²⁻, and the as-obtained composites showed excellent cycling stability with a high retained capacity of 315 mAh g⁻¹ after 500 cycles at 2 A g⁻¹.¹⁸¹ The films constructed with ultrafine Bi nanowires (BNWs) and rGO sheets showed strong structural integrity and exhibited great durable performance as flexible anodes in NIBs.¹⁸² A series of ternary composites of graphene-encapsulated Bi nanoparticles coated with nitrogen-doped carbon was also designed and fabricated. With the confinement of both graphene and carbon, the composites could stand long-term alloying/dealloying cycling.¹⁸³ More pronouncedly, β-Bi nanoparticles were inlayed on graphene nanosheets (Bi/LIG (laser induced graphene)) through a unique laser-induced (LI) compounding method, in which Bi grows with a new [012] oriented phase whose structure is significantly different from bulk Bi. The thermodynamically stable covalent bonds formed between the two-dimensional (2D) puckered layer of β-Bi and LIG. The as-formed structure creates a stable interface between the Bi nanoparticles and LIG, rather than a simple mechanical contact in Bi/GO reported by others. These unique geometric and structural characteristics effectively suppressed the volume expansion of Bi, maintaining the excellent ion and electron transport channels for high-rate applications. As anodes in NIBs, the Bi/LIG composite electrode exhibited a reversible capacity of 122 mAh g⁻¹ at a current density of 4 A g⁻¹ after over 9500 cycles with a capacity decay of only 0.0024% per cycle (Fig. 20).¹⁸⁴ The theoretical calculation based on the DFT demonstrated that the incorporation of graphene could enhance structural stability due to the superior mechanical character, the ion diffusion kinetics, and the Li⁺/Na⁺ storage capacity of the G/Bi heterostructures. The large in-plane elastic modulus of graphene sheets afforded the G/Bi composites with more stable cycling performances.¹⁸⁵

Fig. 19 (a) and (b) Gravimetric and volumetric rate performances of composites of Bi and graphene with different Bi to ratios, respectively. (Bi/G-x, x = the Bi to graphene ratio).¹⁸⁰ Copyright 2020 American Chemical Society.

Fig. 20 (a) Schematic illustration for the preparation of the Bi/LIG electrodes and the anchoring effect of the Bi/LIG composite. (b) SEM images, (c) particle size distribution, and (d) TEM images of the Bi/LIG. (e) Long-term cycling performance and coulombic efficiency of the Bi/LIG at 4 A g⁻¹.¹⁸⁴ Copyright 2022 John Wiley and Sons.

In fact, during the last few years, the composites of Bi and graphene or rGO with different structural features, such as the hierarchical composite of Bi nanodots/graphene (BiND/G),^186,187 the free-standing films of Bi nanosheet (BiNS)/rGO composite with designed porosity,¹⁸⁸ the Bi/C nanospheres with unique petaloid core–shell structure anchored on porous graphene nanosheets,¹⁸⁹ the Bi nanorods wrapped with graphene and N-doped carbon,¹⁹⁰ and the composites of ultrafine Bi nanowire and graphene¹⁹¹ have also been studied as anodes in KIBs. Similar to those on NIBs, these studies demonstrated that even being confined with graphene or rGO, the sizes and morphologies of Bi were still the key factors affecting the interaction between Bi and graphene, the stability of the Bi itself, and the electrochemical performances. Among them, the composites of the Bi nanowire and nanosheets showed better K⁺ storage than those of Bi nanodots.

6. P/graphene composites for AMIBs

Phosphorus (P) is a nonmetallic element, and exists mainly in three allotropes in nature: white, red, and black phosphorus.^192,193 Among them, the white P is volatile, toxic, and inflammable, and thus not suitable for anode materials.¹⁹⁴ The red P (RP) has a polymer structure and is chemically more stable than the white one; its electrical conductivity is extremely low (10⁻¹⁴ S cm⁻¹). As an anode, it needs to be combined with certain conductive materials.¹⁹⁵ The black P (BP) assumes a folded layered structure with the interlayer distance of 5.3 Å, much larger than that of graphite (3.4 Å), which affords it a high electrical conductivity of 0.2–3.3 S cm⁻¹.^196–198 Up to fully alloyed, M₃P (M = Li, Na, K) can be formed to ensure the P with a theoretical specific capacity of 2596 mAh g⁻¹. However, the inevitable volume variations during the alloying/dealloying are a drawback for bare P as an anode.¹⁹⁹ The electrochemical properties of P-based anodes for AMIBs have been explored, and the study has been overwhelmingly reviewed.^{192,193,200–206} Herein, we cover the recent progress on the preparation and applications of the composites of P with graphene derivatives as anodes in AMIBs.

6.1. P/graphene composites for LIBs

Early in 2015, D. Wang and collaborators fabricated composites of RP and graphene nanosheets via ball milling. The composites showed a high initial capacity of 2517 mAh g⁻¹ at room temperature, with 60% capacity retention after 300 cycles at 0.1C (1C = 2600 mAh g⁻¹) and at 60 °C.²⁰⁷ The RP particles adhered to the graphene sheets through a P–O–C bond, which enhanced the contact between P/Li₃P and graphene during the lithiation/delithiation, but the volume variation is problematic. To suppress the volume variation during lithiation/delithiation, the sizes and morphologies of the P particles in the composites were modulated through different fabrication techniques. For example, BP quantum dots (QDs) were distributed on N-doped graphene (NG) nanosheets at a molecular level. The ultrasmall-sized BP QDs shorten the lithium diffusion pathway and decrease the mechanical fracture. The NG nanosheets prevent the aggregation of BP QDs during cycling. These structural features afford the composites with a high reversible capacity of 1271 mAh g⁻¹ at a current density of 500 mA g⁻¹.²⁰⁸ Similarly, by confining the ultrafine RP dots between graphene sheets, the electrochemical performances of the as-obtained composites as anodes in LIBs could be enhanced remarkably, too.^209,210 In addition, the composites of nanosized P particles with graphene always showed better Li⁺ storage than the composites of micronsized P particles with graphene.^211,212

Meanwhile, researchers also evaluated the effect of the morphology of the P/graphene composites on their electrochemical properties. For instance, the amorphous nanoscale RP sheets were deposited on graphene sheets through a simple solution-based method.²¹³ The nanosheet morphology and the amorphous features of RP effectively reduce the volume expansion and mechanical stress; therefore, the P/graphene composites showed superior lithiation/delithiation cycling stability and rate capability, and the capacity could be maintained at 1286 mAh g⁻¹ after 100 cycles at 200 mA g⁻¹, and at 1125 mAh g⁻¹ under a high current density of 1000 mA g⁻¹ (Fig. 21). Moreover, the unique morphologies of both RP and rGO of the RP (nanorod)/rGO (microflowers) composites afford the composites with a high capacity (1760 mAh g⁻¹ at 0.3C), remarkable rate capability (1073 mAh g⁻¹ at 3C), and great cycling stability (1380 mAh g⁻¹ at 0.3C over 300 cycles) (Fig. 22).²¹⁴

Fig. 21 (a) Rate performance of the P/graphene composite at charge/discharge rates from 1000 mA g⁻¹ to 4000 mA g⁻¹, and (b) the corresponding charge/discharge curves. (c) Rate performance of the P/graphene composite at charge rates from 200 mA g⁻¹ to 10 000 mA g⁻¹ at a constant discharge rate of 200 mA g⁻¹, and (d) the corresponding charge/discharge curves.²¹³ Copyright 2017 Royal Society of Chemistry.

Fig. 22 (a) Schematic diagram of the morphology of the composite of RP nanorod and rGO microflowers (RPN/rGF). (b) SEM images of the RPN/rGF composite material. (c) Discharge/charge profiles of the RPN/rGF composite materials, and (d) rate performance at different current densities of the RP and RPN/rGF composite materials. (e) Long-cycling performance of the RP nanorod and rGO microflowers composites at 0.3C (1C = 2600 mA g⁻¹).²¹⁴ Copyright 2021 John Wiley and Sons.

The structural integrity of the P/graphene or P/rGO composite is one of the key factors that impact their electrochemical performance, especially the cycling stability. To date, several strategies have been developed to bind P onto the graphene sheets through chemical bonds to improve the stability of the composites. For example, a sandwiched thin-film anode of the BP/rGO composites (BP and rGO are chemically bonded) for LIBs was fabricated through vacuum filtration followed by a solvothermal reaction at 140 °C. This film-anode exhibited superior cycling performance, with the reversible capacities remaining at 1401 mAh g⁻¹ after the 200th cycle at a current density of 100 mA g⁻¹.²¹⁵ The RP/rGO composites prepared employing electro-spraying and far-infrared reduction (FIR), in which the RP nanoparticles are chemically bonded to the rGO with C–P bonds, delivered a long cycling life of >1000 cycles with ∼99% coulombic efficiency.²¹⁶ Another BP/rGO composite, containing P–O–C and P–C covalent bonds between the BP and rGO prepared by a two-step high-energy ball-milling process, showed excellent electrochemical performance, including the prolonged cycling stability, too (Fig. 23).²¹⁷ Moreover, due to the additional chemical interactions between the P with the N of the N-doped graphene (NG), P/NG composites as anodes in LIBs showed longer cycling lives than that of P/graphene.²¹⁸

Fig. 23 (a) Schematic illustration of the formation of the P–O–C and P–C covalent bonds in the BP/rGO composites during the high energy ball milling processes. (b) Galvanostatic charge–discharge profiles of BP and BP/rGO for the first cycle. (c) Rate performance of BP/rGO. (d) Comparison of BP and BP/rGO in the cycling performance.²¹⁷ Copyright 2020 Royal Society of Chemistry.

6.2. P/graphene composites for NIBs

In contrast to LIBs, more work has been conducted on the P/graphene or P/rGO composites as anodes in NIBs. About ten years ago, the composites of P nanoparticles (ca. 100–150 nm) encapsulated in graphene scrolls and loaded on planar graphene sheets (P/G) were explored as anodes in NIBs. It was found that the P–G had better electrochemical performances as anodes in NIBs than the mixture of P and graphene (P/G). The specific capacity for Na⁺ storage of the P/G composite with a phosphorus content of 52.2% could reach 2355 mAh g⁻¹.²¹⁹ The composites of P/graphene or P/rGO with P quantum dots (<100 nm) as anodes in NIBs were reported, too. It was shown that, with P contents of 55.7–61.4%, the composites could deliver good sodiation/desodiation cycling stability, but poor ICE and low specific capacity due to the larger specific surface area of P quantum dots.^220–222 Notably, the composites of nanoporous RP and rGO (NPRP/rGO) exhibited a superior rate capability and ultralong cycle life (Fig. 24), because the nanoporous structure of the RP component could accommodate the volume change and shorten the ion diffusion distance, and the rGO sheets enhanced the electronic conductivity of the composites.²²³ The self-assembled 2D heterostructures of BP/graphene, formed through electrophoretic deposition with pre-prepared BP/graphene (BP/G) as building blocks, as binder- and additive-free anodes in NIBs, showed a specific discharge capacity of 2365 mAh g⁻¹ and long stable cycling duration.¹⁹⁶

Fig. 24 (a) TEM images of NPRP/rGO. (b) Rate capability of NPRP/rGO as the anode from 0.256 to 5.12 A g⁻¹. (c) Long-term cycling performance of NPRP/rGO anodes at 5.12 A g⁻¹ between 0.01 and 2.0 V.²²³ Copyright 2018 American Chemical Society.

To avoid the structural degradation of P and ensure the robust and intimate contact between P and graphene sheets, D. Golberg et al. fabricated flexible paper made of amorphous P and N-doped graphene, and found that the structural integrity afforded the flexible paper as an anode with ultra-stable cyclic stability and excellent rate capability.²²⁴ The chemically bonded P/graphene composites, prepared through ball/mechanical milling,^225,226 or using 4-nitrobenzenediazonium (4-NBD) as a linker between P and rGO,²²⁷ all showed enhanced electrochemical performances during sodiation/desodiation. The chemically bonded P on graphene or rGO shows great potential for practical applications as anode materials in NIBs.

The P/graphene or P/rGO composites with more complicated morphologies and multi-components have also been proposed as anode materials in NIBs. To mention a few, the layered BP/rGO composites were synthesized through a simple and scalable method, and as a binder-free and conductive agent-free anode in NIBs, the layered composites achieved a specific charge capacity of 720.8 mAh g⁻¹, and it was maintained at 640 mAh g⁻¹ after 500 cycles at a current density of 40 A g⁻¹ (Fig. 25).²²⁸ The 3D RP/rGO aerogel as anodes for NIBs showed a high initial Na-ion storage capacity of 2427 mAh g⁻¹ with an ICE of ∼82% at 0.1 A g⁻¹.²²⁹ Similarly, an integrated carbon/RP/graphene aerogel 3D architecture also delivered high electrochemical performances as an anode in NIBs.²³⁰ There were some ternary composites, such as RP/carbon nanofibers/graphene free-standing paper and conductive polymer-coated RP encapsulated in 3D graphene oxide aerogel have been reported, and all showed manifest electrochemical performances as anodes in NIBs.^231,232 However, to improve the volumetric specific capacity of those materials as an anode, especially the aerogels, is challenging. In addition to the improved electrochemical performances, the RP/rGO film presented good flame retardancy.²³³ To understand the specific role of graphene in the composites of P/graphene as the anode, Cui's group investigated the structural variations of sandwiched P/graphene using in situ TEM and ex situ XRD during electrochemical processing, and found that the graphene sheets not only enhance the composite's electrical conductivity but also provides elastic buffering for P nanocrystal expansion along the y and z axes.²³⁴ Han et al. tried to understand the effects of the graphene on the electrochemical performance of P/G composites through first-principles calculations, and illustrated that the as-incorporated graphene sheets as buffer layers could reduce the volume expansion by 30% in comparison with the bare BP during sodiation, and maintained the conductive pathways even at high sodiation levels.²³⁵

Fig. 25 (a) and (b) Cross-section SEM images of the layered RP/rGO films before and after pressurization. (c) Cycling performance of the layered BP/rGO anodes at current densities of 1 and 40 A g⁻¹, respectively. (d) Charging and discharging potential profiles at 1 A/g current density. (e) Rate performance of the BP/rGO anode for a series of tests with five cycles at each value of current density.²²⁸ Copyright 2018 American Chemical Society.

Similar to in LIBs and NIBs, P-based materials have long been studied as anodes in KIBs, and there are several review articles available for readers.^236–238 Differing from those in LIBs and NIBs, the common stable alloying products of P with potassium are KP and K₄P₃, accompanied by the theoretical capacities of 865 mAh g⁻¹ and 1154 mAh g⁻¹, respectively, lower than those in LIBs and NIBs, 2596 mAh g⁻¹.^238,239 The formation of the K₄P₃ usually results in poor cyclic stability, and the capacity retention drops down to ∼9% after a few cycles. With the superior mechanical integrity and carrier conductivity of rGO, a composite of few-layer P and rGO (FLP/rGO) was generated, and as the anode in KIBs, it delivered a specific capacity (710 mAh g⁻¹ at 0.1C), a reasonable rate capability (∼200 mAh g⁻¹ at 1.2C), and a good cycling stability (∼230 mAh g⁻¹ at 0.5C after 300 cycles) (Fig. 26).²⁴⁰ The RP nanoparticles deposited on rGO sheets through the evaporation condensation process delivered a manifest K⁺ storage capacity, superior cycling stability, and good rate capability.²⁴¹

Fig. 26 (a) and (b) Schematic presentation and TEM image of FLP/rGO. (c) Electrochemical charge/discharge voltage profile of FLP/rGO as an anode in KIBs (1 : 3, ratio of FLP to rGO in weight). (d) Rate capability of FLP/rGO (1 : 3) at current densities from 0.1 to 1.2C. (e) Cycling performance of FLP/rGO (1 : 3) at a current density of ∼0.5C.²⁴⁰ Copyright 2019 American Chemical Society.

7. Summary and outlook

In summary, the recent research advances on composites of graphene or its derivatives with Sn, Ge, Sb, Bi, and P as active anode materials in AMIBs have been reviewed. The typical values of the electrochemical properties and the corresponding fabrication methods of some representative composites of Sn, Sb, Ge, Bi, and P with graphene and derivatives as anodes for AMIBs are summarized in Table 1. Notably, the composites of Sb with graphene and derivatives show enhanced electrochemical performances as anodes in all LIBs, NIBs and KIBs; the composites of Sn and Ge deliver better electrochemical properties in LIBs than those in NIBs and KIBs; the Bi based composites show superior electrochemical performances in NIBs and KIBs than in LIBs, especially a higher volumetric capacity; the composites of P exhibit manifest electrochemical properties in LIBs and NIBs, but seem not to in KIBs. In addition, it can be found that a variety of methods have been developed for the AAM/graphene composite preparations, but there is not a general approach for all kinds of the composites of AAM with graphene and the derivatives, due to the advantages and disadvantages of each method, the different physical and chemical properties of Sn, Sb, Ge, Bi, and P, and the unique morphology and properties of graphene derivatives.

Table 1 Typical values of the electrochemical properties of some representative composites of Sn, Sb, Ge, Bi, and P with graphene and derivatives as anodes for AMIBs

AAMs	Composites	AMIBs	Rate performance (mAh g^−1/A g^−1)	Cycle stability (mAh g^−1/A g^−1/cycle)	ICE	Preparation methods	Ref.
Sn	Sn/GS-VAGN	LIBs	151/277C	400/6C/5000	54.2%	MPECVD	242
	Sn/G		488/2C	846/0.2/100	79%	Arc-discharge method	83
	B4C/Sn/AB/rGO	NIBs	116/2	155.5/1.0/500	74.6%	Ball milling	104
	Sn/RGO	KIBs	67.1/2.0	200/0.1/50	49.8%	Liquid phase method	108
Sb	Sb/rGO	LIBs	223/2.0	562.9/0.43/200	52.3%	Liquid phase method	243
	G/Sb/C	NIBs	433/5.0	569.5/0.1/200	81.7%	Liquid phase method	130
	LS-Sb/G		210/6.0	495.2/0.125/100	77.6%	Solvothermal	132
	Sb/C/RGO	KIBs	320/3.0	370/2.0/350	68.0%	Liquid phase method	141
Ge	Ge-QD/NG/NGF	LIBs	800/40C	1171/1.0C/1000	76.4%	CVD	157
	Ge@G/TiO2	NIBs	88/1.0	194/0.1/100	—	Electrospinning	170
Bi	NG/Bi	LIBs	218/1.0	—	60%	Hydrothermal	174
	BNW/G	NIBs	295/5.0	276/1.0/1000	82.7%	Vacuum filtration	182
	Bi/3DGF		180/50	185.2/10/2000	36.0%	Pyrolysis and self-assembly	191
	Bi/rGO	KIBs	55.6/2.0	197.7/0.5/1000	67.4%	Ball milling	187
	BiNS/rGO		100/10	272/0.5/90	70.5%	Vacuum filtration	188
P	P/graphene	LIBs	1125/1.0	1286/0.2/100	72%	Solution-based method	213
	RPN/rGF		1073/3C	1380/0.3C/300	82%	Evaporation–condensation	214
	P/GH		386/10	1200/2.0/1700	—	Hydrothermal	244
	C/P/GA	NIBs	878.6/2C	1095.5/1C/200	75.4%	Evaporation–condensation	230
	BP/rGO		720.8/40	64/40/500	86.6%	Room temperature pressure synthesis	228
	P/RGO hybrid	KIBs	134.4/2.0	253/0.5/500	52.6%	Evaporation–condensation	241

---

More specifically, the single atomic layered morphology, abundant surface functional groups, and ultra-large aromatic structure, accompanied by unique chemical/physical properties including the mechanical and electric properties, render graphene and its derivatives as ideal building blocks for fabricating diverse composites with Sn, Ge, Sb, Bi, and P. The rich conjugated electrons, inherent and post-introduced oxygen, nitrogen, and or sulfur containing functional groups of the graphene and the derivatives serve as binding sites for Sn, Ge, Sb, Bi, and P components and ensure the uniform distribution of each component in the ternary or more complicated structures. The superior mechanical character and relatively inert chemical properties of the carbon backbone of graphene allow the Sn, Ge, Sb, Bi, and P components to be incorporated through mechanical/ball milling, high-energy irradiation deposition, and harsh solution chemistry procedures. With the aforementioned surface functional groups of the graphene, Sn, Ge, Sb, Bi, and P can be chemically bonded onto the graphene carbon backbone, forming the composites with high structural integrity that is beneficial for their electrochemical performances as anodes in AMIBs. The high carrier (electron and ion) mobility of the graphene and its derivatives enhances the rate capability of the composites as the anodes. The mechanical toughness and hierarchical structure, including the rich voids/pores as-formed within composites, can suppress/buffer the volume variation of Sn, Ge, Sb, Bi, and P during alloying/dealloying with alkali metal ions, affording the composite anodes with the demanded cycling stability.

By varying the fabrication procedures and applying appropriate precursors and templates, a series of nanoscaled Sn, Ge, Sb, Bi, and P materials with different morphologies, including nanospheres, nanowires, nanorods, and 2D nanosheets, have been synthesized and used as the functional building blocks for assembling composites with graphene. The size, morphology, and concomitant porous features enrich the structural configuration of the composites, and more pronouncedly, they can enhance the overall electrochemical performances of the composites as anodes in AMIBs. Moreover, through optimizing the structural features of both nano-scaled Sn, Ge, Sb, Bi, or P, and the graphene, such as that using graphene quantum dots, the electrochemical kinetics of the composites for alloying/dealloying can be tuned, which is important for improving the rate capability of composite anodes in AMIBs.

Considering the larger specific surfaces of graphene and its derivatives, and the nanosized Sn, Ge, Sb, Bi, or P, and the dangling bonds on them, the irreversible reactions are usually encouraged during initial electrochemical alloying with alkali metal ions. As a result, using composites of graphene and Sn, Ge, Sb, Bi, or P as anodes often resulted in an unacceptable ICE, far below the requirement for practical applications. As an ongoing endeavor, methods to passivate the surface of composites, including those of the components, are in high demand.

As aforementioned, the composites of graphene and Sn, Ge, Sb, Bi, or P reported to date assume mostly porous structures; thereby, the composites when as anodes usually exhibit large gravimetric, but low volumetric capacities, which are unsatisfactory for compact AMIB fabrication. Therefore, optimizing the composition, such as maximizing the content of the Sn, Ge, Sb, Bi, or P, and balancing the effects of the pores/voids on the electrochemical kinetics and volumetric capacity, is worth pursuing.

Although there have been many protocols proposed for the preparations of graphene and derivatives, and nanosized Sn, Ge, Sb, Bi, and P, the control of their size and morphology, the bulk-scale production, and the manufacturing costs of those nanomaterials for industrial applications are still challenging.

Additionally, the characterizations of the electrochemical properties of the composites reviewed so far were carried out mostly on half-coin cells with an alkali metal as the counter electrode. With this kind of setup, there are plenty of alkali metal ions provided during the alloying/dealloying cycling, and it is different from a full cell. Thus, the practical electrochemical performances of those composites as anodes, including the suitability with different electrolytes and cathodes, remain to be debated.

Optimally, with further progress on the rational design, the controllable fabrication, the comprehensive characterizations, and the deeper understanding of the relationships among structure–property–performance, the composites of graphene with Sn, Ge, Sb, Bi, or P as anodes should find practical applications in the next generation of high-energy and/or high-power density AMIBs.

Author contributions

Qian Zhao: investigation, conceptualization, and writing – original draft. Shouwu Guo: supervision, methodology, and writing – review &editing.

Conflicts of interest

The authors declare no competing financial interests.

Data availability

No primary research results, software or code have been included and no new data were generated or analysed as part of this review.

Acknowledgements

The work was financially supported by Xian Times Graphene New Energy Technology Co., Ltd (Shaanxi, China).

References

1. X. Wang, S. Tang, W. Guo, Y. Fu and A. Manthiram, Mater. Today, 2021, 50, 259–275.
2. T. Shao, C. Liu, W. Deng, C. Li, X. Wang, M. Xue and R. Li, Batteries Supercaps, 2019, 2, 403–427.
3. H. Zhang, S. Zhao and F. Huang, J. Mater. Chem. A, 2021, 9, 27140–27169.
4. J. Zhang, J. Han, Q. Yun, Q. Li, Y. Long, G. Ling, C. Zhang and Q.-H. Yang, Small Sci., 2021, 1, 2000063.
5. A. K. Ipadeola, A. M. Abdullah and K. Eid, Energy Mater., 2024, 4, 400079.
6. L. Duan, Y. Zhang, H. Tang, J. Liao, G. Zhou and X. Zhou, Adv. Mater., 2024, 37, 2411426.
7. M. Ma, S. Guo and W. Shen, ACS Appl. Mater. Interfaces, 2018, 10, 2612–2618.
8. M. Ma, J. Zhang, W. Shen and S. Guo, J. Solid State Electrochem., 2019, 23, 2969–2977.
9. Y. Lyu, X. Wu, K. Wang, Z. Feng, T. Cheng, Y. Liu, M. Wang, R. Chen, L. Xu, J. Zhou, Y. Lu and B. Guo, Adv. Energy Mater., 2020, 11, 2000982.
10. D. Chao, L. Wang, W. Shen and S. Guo, J. Alloys Compd., 2019, 785, 557–562.
11. H. Li, L. Peng, D. Wu, J. Wu, Y. J. Zhu and X. Hu, Adv. Energy Mater., 2019, 9, 1802930.
12. H. Wu, Q. Liu and S. Guo, Nano-Micro Lett., 2014, 6, 316–326.
13. L. Zhao, B. Ding, X. Y. Qin, Z. Wang, W. Lv, Y. B. He, Q. H. Yang and F. Kang, Adv. Mater., 2022, 34, 2106704.
14. S. Chen, C. Liu, R. Feng, Z. Chen, Y. Lu, L. Chen, Q. Huang, Y. Guan, W. Yan, Y. Su, N. Li and F. Wu, Chem. Eng. J., 2025, 503, 158116.
15. M. Zhong, J. Yan, L. Wang, Y. Huang, L. Li, S. Gao, Y. Tian, W. Shen, J. Zhang and S. Guo, Sustainable Mater. Technol., 2022, 33, e00476.
16. L. Li, W. Zhang, W. Pan, M. Wang, H. Zhang, D. Zhang and D. Zhang, Nanoscale, 2021, 13, 19291–19305.
17. H. Zhao, H. Zuo, J. Wang and S. Jiao, J. Energy Storage, 2024, 98, 113125.
18. Y. Liu, H. Shi and Z.-S. Wu, Energy Environ. Sci., 2023, 16, 4834–4871.
19. K. Yuan, Y. Lin, X. Li, Y. Ding, P. Yu, J. Peng, J. Wang, H. Liu and S. Dou, Energy Environ. Mater., 2024, 7, e12759.
20. J. Lu, Z. Chen, F. Pan, Y. Cui and K. Amine, Electrochem. Energy Rev., 2018, 1, 35–53.
21. S. R. Mishra, V. Chavda, S. Roy, N. Sarkar, V. Gadore, M. Ahmaruzzaman and B. M. Nagaraja, J. Energy Storage, 2025, 108, 115026.
22. P. K. Nayak, L. Yang, W. Brehm and P. Adelhelm, Angew. Chem., Int. Ed., 2017, 57, 102–120.
23. S. W. Kim, D. H. Seo, X. Ma, G. Ceder and K. Kang, Adv. Energy Mater., 2012, 2, 710–721.
24. R. Wanison, W. N. H. Syahputra, N. Kammuang-lue, P. Sakulchangsatjatai, C. Chaichana, V. U. Shankar, P. Suttakul and Y. Mona, J. Energy Storage, 2024, 100, 113497.
25. A. Kumar Prajapati and A. Bhatnagar, J. Energy Chem., 2023, 83, 509–540.
26. Y. P. Deng, Z. G. Wu, R. Liang, Y. Jiang, D. Luo, A. Yu and Z. Chen, Adv. Funct. Mater., 2019, 29, 1808522.
27. K. Song, C. Liu, L. Mi, S. Chou, W. Chen and C. Shen, Small, 2019, 17, 1903194.
28. H. Rghioui, M. S. Zyane, H. R. Jappor, M. Diani, A. Marjaoui and M. Zanouni, J. Phys. Chem. Solids, 2025, 201, 112660.
29. J. Qian, C. Wu, Y. Cao, Z. Ma, Y. Huang, X. Ai and H. Yang, Adv. Energy Mater., 2018, 8, 1702619.
30. Q. Zhang, Z. Wang, S. Zhang, T. Zhou, J. Mao and Z. Guo, Electrochem. Energy Rev., 2018, 1, 625–658.
31. A. Eftekhari and D.-W. Kim, J. Power Sources, 2018, 395, 336–348.
32. E. Olsson, J. Yu, H. Zhang, H. M. Cheng and Q. Cai, Adv. Energy Mater., 2022, 12, 2200662.
33. W. Lee, J. Kim, S. Yun, W. Choi, H. Kim and W.-S. Yoon, Energy Environ. Sci., 2020, 13, 4406–4449.
34. M. Peng, K. Shin, L. Jiang, Y. Jin, K. Zeng, X. Zhou and Y. Tang, Angew. Chem., Int. Ed., 2022, 61, e202206770.
35. S. Liang, Y. J. Cheng, J. Zhu, Y. Xia and P. Müller-Buschbaum, Small Methods, 2020, 4, 2000218.
36. X.-Y. Li, J.-K. Qu and H.-Y. Yin, Rare Met., 2020, 40, 329–352.
37. S. Imtiaz, I. S. Amiinu, Y. Xu, T. Kennedy, C. Blackman and K. M. Ryan, Mater. Today, 2021, 48, 241–269.
38. G. Yang, P. R. Ilango, S. Wang, M. S. Nasir, L. Li, D. Ji, Y. Hu, S. Ramakrishna, W. Yan and S. Peng, Small, 2019, 15, 1900628.
39. G. Li, S. Guo, B. Xiang, S. Mei, Y. Zheng, X. Zhang, B. Gao, P. K. Chu and K. Huo, Energy Mater., 2022, 2, 200020.
40. Y. S. Choi, D. O. Scanlon and J. C. Lee, Adv. Energy Mater., 2020, 11, 2003078.
41. M. Lao, Y. Zhang, W. Luo, Q. Yan, W. Sun and S. X. Dou, Adv. Mater., 2017, 29, 1700622.
42. A. K. Geim and K. S. Novoselov, Nat. Mater., 2007, 6, 183–191.
43. M. J. Allen, V. C. Tung and R. B. Kaner, Chem. Rev., 2010, 110, 132–145.
44. J. Zhang, H. Yang, G. Shen, P. Cheng, J. Zhang and S. Guo, Chem. Commun., 2010, 46, 1112–1114.
45. J. Yan, M. Zhong, C. Yu, J. Zhang, M. Ma, L. Li, Q. Hao, F. Gao, Y. Tian, Y. Huang, W. Shen and S. Guo, Synth. Met., 2020, 263, 116364.
46. J. Zhang, B. Guo, Y. Yang, W. Shen, Y. Wang, X. Zhou, H. Wu and S. Guo, Carbon, 2015, 84, 469–478.
47. Z. Sun, Y. Wang, X. Jiang, Y. Bando and X. Wang, EnergyChem, 2025, 7, 100149.
48. H. Wu and Y. Cui, Nano Today, 2012, 7, 414–429.
49. J. Reslan, M. Saadaoui and T. Djenizian, Adv. Mater. Interfaces, 2024, 11, 2301062.
50. H. E. Kang, J. Ko, S. G. Song and Y. S. Yoon, Carbon, 2024, 219, 118800.
51. V. V. Kulish, O. I. Malyi, M.-F. Ng, Z. Chen, S. Manzhos and P. Wu, Phys. Chem. Chem. Phys., 2014, 16, 4260–4267.
52. M. K. Jangid, A. Vemulapally, F. J. Sonia, M. Aslam and A. Mukhopadhyay, J. Electrochem. Soc., 2017, 164, A2559–A2565.
53. S. Lee, S. C. Jung and Y.-K. Han, J. Power Sources, 2019, 415, 119–125.
54. J.-Y. Li, Q. Xu, G. Li, Y.-X. Yin, L.-J. Wan and Y.-G. Guo, Mater. Chem. Front., 2017, 1, 1691–1708.
55. A. Daali, X. Zhou, C. Zhao, I. Hwang, Z. Yang, Y. Liu, R. Amine, C.-J. Sun, W. Otieno, G.-L. Xu and K. Amine, Nano Energy, 2023, 115, 108753.
56. B. Zhang, G. Rousse, D. Foix, R. Dugas, D. A. D. Corte and J. M. Tarascon, Adv. Mater., 2016, 28, 9824–9830.
57. H. Ying and W. Q. Han, Adv. Sci., 2017, 4, 1700298.
58. G. Masing and G. Tammann, Z. Anorg. Chem., 2004, 67, 183–199.
59. W. Li, X. Sun and Y. Yu, Small Methods, 2017, 1, 1600037.
60. P. Gandharapu and A. Mukhopadhyay, Appl. Mech. Rev., 2022, 74, 060802.
61. Z. Li, J. Ding and D. Mitlin, Acc. Chem. Res., 2015, 48, 1657–1665.
62. Y. Zhao, X. Li, B. Yan, D. Li, S. Lawes and X. Sun, J. Power Sources, 2015, 274, 869–884.
63. Y. Shan, Y. Li and H. Pang, Adv. Funct. Mater., 2020, 30, 2001298.
64. J.-M. Liang, L.-J. Zhang, D.-G. XiLi and J. Kang, Rare Met., 2020, 39, 1005–1018.
65. F. Xin and M. S. Whittingham, Electrochem. Energy Rev., 2020, 3, 643–655.
66. X. L. Wu, Y. G. Guo and L. J. Wan, Chem. – Asian J., 2013, 8, 1948–1958.
67. R. Hu, H. Liu, M. Zeng, J. Liu and M. Zhu, Chin. Sci. Bull., 2012, 57, 4119–4130.
68. L. Liu, F. Xie, J. Lyu, T. Zhao, T. Li and B. G. Choi, J. Power Sources, 2016, 321, 11–35.
69. G. Wang, B. Wang, X. Wang, J. Park, S. Dou, H. Ahn and K. Kim, J. Mater. Chem., 2009, 19, 8378–8384.
70. W. Yue, S. Yang, Y. Liu and X. Yang, Mater. Res. Bull., 2013, 48, 1575–1580.
71. Y. Li, H. Ren, Y. Zhao, Z. Guo, C. Ma, R. Wu, C.-M. Chen and Y. Zhao, J. Alloys Compd., 2023, 937, 168421.
72. S. Chen, Y. Wang, H. Ahn and G. Wang, J. Power Sources, 2012, 216, 22–27.
73. X. Zhou, Y. Zou and J. Yang, J. Power Sources, 2014, 253, 287–293.
74. P. P. Prosini, M. Carewska, G. Tarquini, F. Maroni, A. Birrozzi and F. Nobili, Ionics, 2015, 22, 515–528.
75. F. R. Beck, R. Epur, D. Hong, A. Manivannan and P. N. Kumta, Electrochim. Acta, 2014, 127, 299–306.
76. C. Wang, Y. Li, Y.-S. Chui, Q.-H. Wu, X. Chen and W. Zhang, Nanoscale, 2013, 5, 10599.
77. F. Pan, W. Zhang, J. Ma, N. Yao, L. Xu, Y.-S. He, X. Yang and Z.-F. Ma, Electrochim. Acta, 2016, 196, 572–578.
78. X. Zhou, J. Bao, Z. Dai and Y.-G. Guo, J. Phys. Chem. C, 2013, 117, 25367–25373.
79. Y. Zhong, M. Yang, X. Zhou, J. Wei and Z. Zhou, Part. Part. Syst. Charact., 2014, 32, 104–111.
80. L. Liu, X. Huang, X. Guo, S. Mao and J. Chen, J. Power Sources, 2016, 328, 482–491.
81. J. Wang, J. Yang, Q. Xiao, L. Jia, H. Lin and Y. Zhang, ACS Appl. Mater. Interfaces, 2019, 11, 30500–30507.
82. B. Luo, B. Wang, X. Li, Y. Jia, M. Liang and L. Zhi, Adv. Mater., 2012, 24, 3538–3543.
83. C. Wang, J. Ju, Y. Yang, Y. Tang, H. Bi, F. Liao, J. Lin, Z. Shi, F. Huang and R. P. S. Han, RSC Adv., 2013, 3, 21588.
84. B. Luo, B. Wang, M. Liang, J. Ning, X. Li and L. Zhi, Adv. Mater., 2012, 24, 1405–1409.
85. Q. Jian, C. He, N. Zhao, Z. Wang, C. Shi, E.-Z. Liu and J. Li, ACS Nano, 2014, 8, 1728–1738.
86. J. Zhu, A. Liu and D. Wang, Appl. Surf. Sci., 2017, 416, 751–756.
87. G. Zeb, P. Gaskell, K. Hu, Y. N. Kim, X. Xiao, T. Szkopek and M. Cerruti, J. Phys. Chem. C, 2017, 121, 16682–16692.
88. R. Pouyanmehr, M. K. Hassanzadeh-Aghdam and R. Ansari, Mech. Mater., 2020, 145, 103390.
89. F. Wan, H.-Y. Lü, X.-L. Wu, X. Yan, J.-Z. Guo, J.-P. Zhang, G. Wang, D.-X. Han and L. Niu, Energy Storage Mater., 2016, 5, 214–222.
90. V. L. Chevrier and G. Ceder, J. Electrochem. Soc., 2011, 158, A1011–A1014.
91. J. W. Wang, X. H. Liu, S. X. Mao and J. Y. Huang, Nano Lett., 2012, 12, 5897–5902.
92. L. Wang, J. Zhu, N. Li, Z. Zhang, S. Zhang, Y. Chen, J. Zhang, Y. Yang, L. Tan, X. Niu, X. Wang, X. Ji and Y. Zhu, Energy Environ. Sci., 2024, 17, 3470–3481.
93. H. Li, Z. Liu, L. Li, Y. Zhang, Z. Li, H. Lan, Z. Zhu, Y. Wu, J. Li, C. Zheng and J. Lu, Carbon Energy, 2025, e703.
94. J. Yu, M. Jiang, W. Zhang, G. Li, R. A. Soomro, N. Sun and B. Xu, Small Methods, 2023, 7, 2300708.
95. A. J. Naylor, M. Carboni, M. Valvo and R. Younesi, ACS Appl. Mater. Interfaces, 2019, 11, 45636–45645.
96. K. Xiong, T. Qi and X. Zhang, Electroanalysis, 2025, 37, e202400318.
97. J. Zhang and J. Zhao, J. Energy Storage, 2023, 72, 108366.
98. A. G. Morachevskii, Russ. J. Appl. Chem., 2019, 91, 1785–1798.
99. C. Hu, X. Hou, Z. Bai, L. Yun, X. Zhang, N. Wang and J. Yang, Chin. J. Chem., 2021, 39, 2931–2942.
100. A. Kempf, M. Graczyk-Zajac and R. Riedel, ACS Mater. Lett., 2024, 7, 275–285.
101. J. Hwang, D. Nam and J. Kim, J. Supercrit. Fluids, 2022, 189, 105720.
102. Z. Liu, S. Zhang, Z. Qiu, C. Huangfu, L. Wang, T. Wei and Z. Fan, Small, 2020, 16, 2003557.
103. Y. Jeon, X. Han, K. Fu, J. Dai, J. H. Kim, L. Hu, T. Song and U. Paik, J. Mater. Chem. A, 2016, 4, 18306–18313.
104. Y. Sun, Y. Yang, X.-L. Shi, G. Suo, S. Lu and Z.-G. Chen, Appl. Mater. Today, 2021, 24, 101137.
105. H. Li, Z. Fu, H. Kang, R. Wang, R. Hua, Q. Ma, L. Zhang, C. Zhang and T. Zhou, ACS Appl. Mater. Interfaces, 2022, 14, 8086–8094.
106. Y. Gu, Y. Ru Pei, M. Zhao, C. Cheng Yang and Q. Jiang, Chem. Rec., 2022, 22, e202200098.
107. Q. Wang, X. Zhao, C. Ni, H. Tian, J. Li, Z. Zhang, S. X. Mao, J. Wang and Y. Xu, J. Phys. Chem. C, 2017, 121, 12652–12657.
108. H. Wang, Z. Xing, Z. Hu, Y. Zhang, Y. Hu, Y. Sun, Z. Ju and Q. Zhuang, Appl. Mater. Today, 2019, 15, 58–66.
109. B. Chen, M. Liang, Q. Wu, S. Zhu, N. Zhao and C. He, Trans. Tianjin Univ., 2021, 28, 6–32.
110. W. Luo, J.-J. Gaumet and L.-Q. Mai, Rare Met., 2017, 36, 321–338.
111. Y. Zhang, J. Xie, T. Zhu, G. Cao, X. Zhao and S. Zhang, J. Power Sources, 2014, 247, 204–212.
112. Y. Yi, H.-W. Shim, S.-D. Seo, M. A. Dar and D.-W. Kim, Mater. Res. Bull., 2016, 76, 338–343.
113. X. Zhou, J. Ding, H. Lu, Z. Qi and C. Yan, Mater. Chem. Phys., 2021, 270, 124873.
114. Z. Yi, Q. Han, Y. Cheng, F. Wang, Y. Wu and L. Wang, Electrochim. Acta, 2016, 190, 804–810.
115. Y. Mu, D. Zhang, J. Li, B. Han, G. Xu, K. Wang, B. An, D. Ju, L. Li and W. Zhou, Electrochim. Acta, 2023, 437, 141532.
116. A. Darwiche, C. Marino, M. T. Sougrati, B. Fraisse, L. Stievano and L. Monconduit, J. Am. Chem. Soc., 2012, 134, 20805–20811.
117. L. Hu, X. Zhu, Y. Du, Y. Li, X. Zhou and J. Bao, Chem. Mater., 2015, 27, 8138–8145.
118. F. Wan, H.-Y. Lü, X.-H. Zhang, D.-H. Liu, J.-P. Zhang, X. He and X.-L. Wu, J. Alloys Compd., 2016, 672, 72–78.
119. F. Wan, J.-Z. Guo, X.-H. Zhang, J.-P. Zhang, H.-Z. Sun, Q. Yan, D.-X. Han, L. Niu and X.-L. Wu, ACS Appl. Mater. Interfaces, 2016, 8, 7790–7799.
120. Z. Jiang, Y. Zhao, W. Kang, B. Xing, H. Jiang, G. Huang, C. Zhang and Y. Cao, J. Alloys Compd., 2022, 925, 166631.
121. X. Liu, M. Gao, H. Yang, X. Zhong and Y. Yu, Nano Res., 2017, 10, 4360–4367.
122. X. Li, J. Qu, H. Xie, Q. Song, G. Fu and H. Yin, Electrochim. Acta, 2020, 332, 135501.
123. H. Shuai, H. Liu, J. Li, S. Fang, L. Xu, Y. Yang, H. Hou, G. Zou, J. Hu and X. Ji, Inorg. Chem., 2021, 60, 12526–12535.
124. X. Zhang, P. Wu, L. Jiang, X. Zhang, H. Shi, X. Zhu, S. Wei and Y. Zhou, Appl. Surf. Sci., 2018, 444, 448–456.
125. Y. Fang, X. Xu, Y. Du, X. Zhu, X. Zhou and J. Bao, J. Mater. Chem. A, 2018, 6, 11244–11251.
126. H. Y. Lü, F. Wan, L. H. Jiang, G. Wang and X. L. Wu, Part. Part. Syst. Charact., 2016, 33, 204–211.
127. G.-Z. Wang, J.-M. Feng, L. Dong, X.-F. Li and D.-J. Li, J. Alloys Compd., 2017, 693, 141–149.
128. K. Li, D. Su, H. Liu and G. Wang, Electrochim. Acta, 2015, 177, 304–309.
129. J.-S. Park and Y. C. Kang, Chem. Eng. J., 2019, 373, 227–237.
130. J. Wang, J. Yang, W. Yin and S.-i Hirano, J. Mater. Chem. A, 2017, 5, 20623–20630.
131. J. Su, W. Li, T. Duan, B. Xiao, X. Wang, Y. Pei and X. C. Zeng, Carbon, 2019, 153, 767–775.
132. K.-C. Huang, J.-Z. Guo, H.-H. Li, H.-H. Fan, D.-H. Liu, Y.-P. Zheng, W.-L. Li, X.-L. Wu and J.-P. Zhang, J. Alloys Compd., 2018, 731, 881–888.
133. W. Zhang, Y. Liu, C. Chen, Z. Li, Y. Huang and X. Hu, Small, 2015, 11, 3822–3829.
134. A. Amardeep, R. C. Shende, P. Gandharapu, M. S. Wani and A. Mukhopadhyay, ACS Appl. Mater. Interfaces, 2022, 14, 45296–45307.
135. S. Gong, J. Lee and H. S. Kim, J. Korean Ceram. Soc., 2020, 57, 91–97.
136. H. Gao, X. Guo, S. Wang, F. Zhang, H. Liu and G. Wang, EcoMat, 2020, 2, e12027.
137. L. Zhou, Z. Cao, J. Zhang, H. Cheng, G. Liu, G. T. Park, L. Cavallo, L. Wang, H. N. Alshareef, Y. K. Sun and J. Ming, Adv. Mater., 2021, 33, 2005993.
138. D. Y. W. Yu, S. K. Batabyal, J. Gun, S. Sladkevich, A. A. Mikhaylov, A. G. Medvedev, V. M. Novotortsev, O. Lev and P. V. Prikhodchenko, Main Group Met. Chem., 2015, 38, 43–50.
139. L. Wang, J. Jia, Y. Wu and K. Niu, J. Appl. Electrochem., 2018, 48, 1115–1120.
140. X. Yang and R. Zhang, J. Alloys Compd., 2020, 834, 155191.
141. X. Yang, R. Zhang, S. Xu, D. Xu, J. Ma, Z. Zhang and S. Yang, Chem. – Eur. J., 2020, 26, 5818–5823.
142. Y. N. Ko, S. H. Choi, H. Kim and H. J. Kim, ACS Appl. Mater. Interfaces, 2019, 11, 27973–27981.
143. R. R. Moskalyk, Miner. Eng., 2004, 17, 393–402.
144. T. L. Kulova and A. M. Skundin, Russ. J. Electrochem., 2022, 57, 1105–1137.
145. S. Wu, C. Han, J. Iocozzia, M. Lu, R. Ge, R. Xu and Z. Lin, Angew. Chem., Int. Ed., 2016, 55, 7898–7922.
146. M. Vörös, S. Wippermann, B. Somogyi, A. Gali, D. Rocca, G. Galli and G. T. Zimanyi, J. Mater. Chem. A, 2014, 2, 9820–9827.
147. T. L. Kulova, A. M. Skundin and I. M. Gavrilin, Russ. J. Electrochem., 2022, 58, 855–868.
148. X. Xiao, X. Li, S. Zheng, J. Shao, H. Xue and H. Pang, Adv. Mater. Interfaces, 2017, 4, 1600798.
149. C.-Y. Chou and G. S. Hwang, J. Power Sources, 2014, 263, 252–258.
150. J.-G. Ren, Q.-H. Wu, H. Tang, G. Hong, W. Zhang and S.-T. Lee, J. Mater. Chem. A, 2013, 1, 1821–1826.
151. C. Zhong, J.-Z. Wang, X.-W. Gao, D. Wexler and H.-K. Liu, J. Mater. Chem. A, 2013, 1, 10798.
152. X. Zhong, J. Wang, W. Li, X. Liu, Z. Yang, L. Gu and Y. Yu, RSC Adv., 2014, 4, 58184–58189.
153. C. D. Wang, Y. S. Chui, Y. Li, X. F. Chen and W. J. Zhang, Appl. Phys. Lett., 2013, 103, 253903.
154. Y. Chen, Y. Zou, X. Shen, J. Qiu, J. Lian, J. Pu, S. Li, F.-H. Du, S.-Q. Li, Z. Ji and A. Yuan, J. Energy Chem., 2022, 69, 161–173.
155. Y. Xu, X. Zhu, X. Zhou, X. Liu, Y. Liu, Z. Dai and J. Bao, J. Phys. Chem. C, 2014, 118, 28502–28508.
156. J. Qin, X. Wang, M. Cao and C. Hu, Chem. – Eur. J., 2014, 20, 9675–9682.
157. R. Mo, D. Rooney, K. Sun and H. Y. Yang, Nat. Commun., 2017, 8, 13949.
158. C. Wang, J. Ju, Y. Yang, Y. Tang, J. Lin, Z. Shi, R. P. S. Han and F. Huang, J. Mater. Chem. A, 2013, 1, 8897–8902.
159. T. Wang, G. Xie, J. Zhu and B. Lu, Electrochim. Acta, 2015, 186, 64–70.
160. D. Li, K. H. Seng, D. Shi, Z. Chen, H. K. Liu and Z. Guo, J. Mater. Chem. A, 2013, 1, 14115.
161. S. Fang, L. Shen, H. Zheng and X. Zhang, J. Mater. Chem. A, 2015, 3, 1498–1503.
162. S. Jin, N. Li, H. Cui and C. Wang, ACS Appl. Mater. Interfaces, 2014, 6, 19397–19404.
163. B. Wang, J. Jin, X. Hong, S. Gu, J. Guo and Z. Wen, J. Mater. Chem. A, 2017, 5, 13430–13438.
164. W. Lang, C. Yue, M. Dang, G. Wang, Y. Chen, F. Hu, Z. Liu and J. Shu, J. Power Sources, 2023, 560, 232706.
165. S. Feng, X. Li, C. Shang, L. Tang and J. Zhang, J. Non-Cryst. Solids, 2024, 646, 123257.
166. X. Fang, F. Hu, J. Lu, X. Han, J. Pu, Y. Li, C. Yue and Y. Yang, J. Colloid Interface Sci., 2025, 688, 656–663.
167. L. Baggetto, J. K. Keum, J. F. Browning and G. M. Veith, Electrochem. Commun., 2013, 34, 41–44.
168. X. Lu, E. R. Adkins, Y. He, L. Zhong, L. Luo, S. X. Mao, C.-M. Wang and B. A. Korgel, Chem. Mater., 2016, 28, 1236–1242.
169. V. Sharma, K. Ghatak and D. Datta, J. Mater. Sci., 2018, 53, 14423–14434.
170. X. Wang, L. Fan, D. Gong, J. Zhu, Q. Zhang and B. Lu, Adv. Funct. Mater., 2015, 26, 1104–1111.
171. J. H. Jia, X. F. Lu, C. C. Yang and Q. Jiang, J. Mater. Chem. A, 2024, 12, 1359–1391.
172. C.-M. Park, S. Yoon, S.-I. Lee and H.-J. Sohn, J. Power Sources, 2009, 186, 206–210.
173. R. Dai, Y. Wang, P. Da, H. Wu, M. Xu and G. Zheng, Nanoscale, 2014, 6, 13236–13241.
174. Y. Zhang, Q. Wang, B. Wang, Y. Mei and P. Lian, Ionics, 2017, 23, 1407–1415.
175. X. Shang, X. Shi, X. Cao and X. Lu, ChemNanoMat, 2021, 7, 1188–1199.
176. B. Xu, S. Qi, P. He and J. Ma, Chem. – Asian J., 2019, 14, 2925–2937.
177. Y. Wang, X. Xu, F. Li, S. Ji, J. Zhao, J. Liu and Y. Huo, Batteries, 2023, 9, 440.
178. X. Zhou, X. Chen, W. Kuang, X. Zhang, X. Wu, X. Chen, C. Zhang, L. Li and S.-L. Chou, Chem. Sci., 2024, 15, 12189–12199.
179. J. Hwang, J.-H. Park, K. Yoon Chung and J. Kim, Chem. Eng. J., 2020, 387, 124111.
180. C. Xu, Y. Gong, G. Cao, H. Wei, X. Zhang, F. Yin and G. Wang, ACS Sustainable Chem. Eng., 2020, 8, 17327–17334.
181. J. Li, S. Fang, L. Xu, A. Wang, K. Zou, A. Di, F. Li, W. Deng, G. Zou, H. Hou and X. Ji, Electrochim. Acta, 2022, 413, 140174.
182. X. Cheng, H. Yang, C. Wei, F. Huang, Y. Yao, R. Bai, Y. Jiang and S. Li, J. Mater. Chem. A, 2023, 11, 8081–8090.
183. M. Wang, H. Li, X. Cheng, S. Tian and X. Wang, Batteries Supercaps, 2023, 6, e202300055.
184. H. Zhu, F. Wang, L. Peng, T. Qin, F. Kang and C. Yang, Angew. Chem., Int. Ed., 2023, 62, e202212439.
185. M. Ai, J. Sun, Z. Li, H. Liang and C. Liu, J. Phys. Chem. C, 2021, 125, 11391–11401.
186. Y. Zhao, X. Ren, Z. Xing, D. Zhu, W. Tian, C. Guan, Y. Yang, W. Qin, J. Wang, L. Zhang, Y. Huang, W. Wen, X. Li and R. Tai, Small, 2019, 16, 1905789.
187. Y. Wei, P. Zhang, S. Zhou, X. Tian, R. A. Soomro, H. Liu, H. Du and B. Xu, Small, 2024, 20, 2306541.
188. L. Zeng, M. Liu, P. Li, G. Zhou, P. Zhang and L. Qiu, Sci. China Mater., 2020, 63, 1920–1928.
189. F. Zhang, X. Liu, B. Wang, G. Wang and H. Wang, ACS Appl. Mater. Interfaces, 2021, 13, 59867–59881.
190. S. Qiao, Y. Liu, K. Wang and S. Chong, Batteries, 2023, 9, 505.
191. X. Cheng, D. Li, Y. Wu, R. Xu and Y. Yu, J. Mater. Chem. A, 2019, 7, 4913–4921.
192. J. Zhou, Q. Shi, S. Ullah, X. Yang, A. Bachmatiuk, R. Yang and M. H. Rummeli, Adv. Funct. Mater., 2020, 30, 2004648.
193. L. Zeng, L. Huang, J. Zhu, P. Li, P. K. Chu, J. Wang and X. F. Yu, Small, 2022, 18, 2201808.
194. J. Ni, L. Li and J. Lu, ACS Energy Lett., 2018, 3, 1137–1144.
195. I. Capone, J. Aspinall, E. Darnbrough, Y. Zhao, T.-U. Wi, H.-W. Lee and M. Pasta, Matter, 2020, 3, 2012–2028.
196. M. Li, N. Muralidharan, K. Moyer and C. L. Pint, Nanoscale, 2018, 10, 10443–10449.
197. C. Liu, X. Han, Y. Cao, S. Zhang, Y. Zhang and J. Sun, Energy Storage Mater., 2019, 20, 343–372.
198. J. Mei, T. Liao and Z. Sun, Adv. Sustainable Syst., 2022, 6, 2200301.
199. H. Jin, H. Wang, Z. Qi, D. S. Bin, T. Zhang, Y. Wan, J. Chen, C. Chuang, Y. R. Lu, T. S. Chan, H. Ju, A. M. Cao, W. Yan, X. Wu, H. Ji and L. J. Wan, Angew. Chem., Int. Ed., 2019, 59, 2318–2322.
200. S. Dong, L. Wang, X. Huang, J. Liang and X. He, Batteries Supercaps, 2023, 6, e202300265.
201. J. Sun, G. Zheng, H.-W. Lee, N. Liu, H. Wang, H. Yao, W. Yang and Y. Cui, Nano Lett., 2014, 14, 4573–4580.
202. Q. Xia, W. Li, Z. Miao, S. Chou and H. Liu, Nano Res., 2017, 10, 4055–4081.
203. X. Lan, Z. Li, Y. Zeng, C. Han, J. Peng and H. M. Cheng, EcoMat, 2024, 6, e12452.
204. X. Qin, B. Yan, J. Yu, J. Jin, Y. Tao, C. Mu, S. Wang, H. Xue and H. Pang, Inorg. Chem. Front., 2017, 4, 1424–1444.
205. H. S. Tsai, Small Methods, 2022, 6, 2200735.
206. H. Zhang, L. Wang, H. Li and X. He, ACS Energy Lett., 2021, 6, 3719–3724.
207. Z. Yu, J. Song, M. L. Gordin, R. Yi, D. Tang and D. Wang, Adv. Sci., 2015, 2, 1400020.
208. L. Pan, X.-D. Zhu, K.-N. Sun, Y.-T. Liu, X.-M. Xie and X.-Y. Ye, Nano Energy, 2016, 30, 347–354.
209. L. Wang, H. Guo, W. Wang, K. Teng, Z. Xu, C. Chen, C. Li, C. Yang and C. Hu, Electrochim. Acta, 2016, 211, 499–506.
210. J. Ruan, Y. Pang, S. Luo, T. Yuan, C. Peng, J. Yang and S. Zheng, J. Mater. Chem. A, 2018, 6, 20804–20812.
211. X. Zhu, Z. Yuan, X. Wang, G. Jiang, J. Xiong and S. Yuan, Appl. Surf. Sci., 2018, 433, 125–132.
212. T. Wang, S. Wei, R. Villegas Salvatierra, X. Han, Z. Wang and J. M. Tour, ACS Appl. Mater. Interfaces, 2018, 10, 38936–38943.
213. L. Sun, Y. Zhang, D. Zhang and Y. Zhang, Nanoscale, 2017, 9, 18552–18560.
214. T. Wang, F. Cheng, N. Zhang, W. Tian, J. Zhou, R. Zhang, J. Cao, M. Luo, N. Li, L. Jiang, D. Li, Y. Li, K. Liang, H. Liu, P. Chen and B. Kong, Adv. Eng. Mater., 2021, 23, 2001507.
215. H. Liu, Y. Zou, L. Tao, Z. Ma, D. Liu, P. Zhou, H. Liu and S. Wang, Small, 2017, 13, 1700758.
216. Z. Yue, T. Gupta, F. Wang, C. Li, R. Kumar, Z. Yang and N. Koratkar, Carbon, 2018, 127, 588–595.
217. Y. Shi, Z. Yi, Y. Kuang, H. Guo, Y. Li, C. Liu and Z. Lu, Chem. Commun., 2020, 56, 11613–11616.
218. X. Jiao, Y. Liu, T. Li, C. Zhang, X. Xu, O. O. Kapitanova, C. He, B. Li, S. Xiong and J. Song, ACS Appl. Mater. Interfaces, 2019, 11, 30858–30864.
219. L. Pei, Q. Zhao, C. Chen, J. Liang and J. Chen, ChemElectroChem, 2015, 2, 1652–1655.
220. G. Zeng, X. Hu, B. Zhou, J. Chen, C. Cao and Z. Wen, Nanoscale, 2017, 9, 14722–14729.
221. Y. Liu, A. Zhang, C. Shen, Q. Liu, X. Cao, Y. Ma, L. Chen, C. Lau, T.-C. Chen, F. Wei and C. Zhou, ACS Nano, 2017, 11, 5530–5537.
222. N. Feng, X. Liang, X. Pu, M. Li, M. Liu, Z. Cong, J. Sun, W. Song and W. Hu, J. Alloys Compd., 2019, 775, 1270–1276.
223. S. Liu, H. Xu, X. Bian, J. Feng, J. Liu, Y. Yang, C. Yuan, Y. An, R. Fan and L. Ci, ACS Nano, 2018, 12, 7380–7387.
224. C. Zhang, X. Wang, Q. Liang, X. Liu, Q. Weng, J. Liu, Y. Yang, Z. Dai, K. Ding, Y. Bando, J. Tang and D. Golberg, Nano Lett., 2016, 16, 2054–2060.
225. J. Song, Z. Yu, M. L. Gordin, S. Hu, R. Yi, D. Tang, T. Walter, M. Regula, D. Choi, X. Li, A. Manivannan and D. Wang, Nano Lett., 2014, 14, 6329–6335.
226. S.-B. Yu, D. Susanto, E. S. Chang, H.-K. Shin, Y. G. Jeon, S. Y. Hwang, S.-H. Lee, K.-B. Kim and H.-K. Kim, J. Energy Storage, 2024, 92, 111998.
227. H. Liu, L. Tao, Y. Zhang, C. Xie, P. Zhou, H. Liu, R. Chen and S. Wang, ACS Appl. Mater. Interfaces, 2017, 9, 36849–36856.
228. Y. Liu, Q. Liu, A. Zhang, J. Cai, X. Cao, Z. Li, P. D. Asimow and C. Zhou, ACS Nano, 2018, 12, 8323–8329.
229. Y. Yan, S. Xia, H. Sun, Y. Pang, J. Yang and S. Zheng, Chem. Eng. J., 2020, 393, 124788.
230. H. Gao, T. Zhou, Y. Zheng, Y. Liu, J. Chen, H. Liu and Z. Guo, Adv. Energy Mater., 2016, 6, 1601037.
231. X. Ma, L. Chen, X. Ren, G. Hou, L. Chen, L. Zhang, B. Liu, Q. Ai, L. Zhang, P. Si, J. Lou, J. Feng and L. Ci, J. Mater. Chem. A, 2018, 6, 1574–1581.
232. Y. Zhu, X. Tang, Z. You, Y. Zhang, W. Du, Y. Duan, J. Cai and Y. Zhang, J. Electroanal. Chem., 2024, 966, 118413.
233. Y. Liu, A. Zhang, C. Shen, Q. Liu, J. Cai, X. Cao and C. Zhou, Nano Res., 2018, 11, 3780–3790.
234. J. Sun, H.-W. Lee, M. Pasta, H. Yuan, G. Zheng, Y. Sun, Y. Li and Y. Cui, Nat. Nanotechnol., 2015, 10, 980–985.
235. H. W. Lee, H. Jung, B. C. Yeo, D. Kim and S. S. Han, J. Phys. Chem. C, 2018, 122, 20653–20660.
236. D. Yang, C. Liu, X. Rui and Q. Yan, Nanoscale, 2019, 11, 15402–15417.
237. Y. Wu, H. B. Huang, Y. Feng, Z. S. Wu and Y. Yu, Adv. Mater., 2019, 31, 1901414.
238. H. Kim, J. C. Kim, M. Bianchini, D. H. Seo, J. Rodriguez-Garcia and G. Ceder, Adv. Energy Mater., 2017, 8, 1702384.
239. P. Xiong, P. Bai, S. Tu, M. Cheng, J. Zhang, J. Sun and Y. Xu, Small, 2018, 14, 1802140.
240. R. Jain, P. Hundekar, T. Deng, X. Fan, Y. Singh, A. Yoshimura, V. Sarbada, T. Gupta, A. S. Lakhnot, S. O. Kim, C. Wang and N. Koratkar, ACS Nano, 2019, 13, 14094–14106.
241. H. Wang, L. Wang, L. Wang, Z. Xing, X. Wu, W. Zhao, X. Qi, Z. Ju and Q. Zhuang, Chem. – Eur. J., 2018, 24, 13897–13902.
242. N. Li, H. Song, H. Cui and C. Wang, Nano Energy, 2014, 3, 102–112.
243. W. Yin, W. Chai, K. Wang, W. Ye, Y. Rui and B. Tang, J. Alloys Compd., 2019, 797, 1249–1257.
244. J. Mei, T. He, Q. Zhang, T. Liao, A. Du, G. A. Ayoko and Z. Sun, ACS Appl. Mater. Interfaces, 2020, 12, 21720–21729.

---