Themed collection FOCUS: Recent Advance in Supercapacitors

In this study, the preparation methods of MXenes and layered dihydroxides (LDHs) are reviewed. In addition, the preparation and the electrochemical performances for supercapacitors of MXene/LDHs composites are summarized in detail.

The methods for the preparation and modification of layered double hydroxides (LDHs) in recent years are reviewed in this paper. In addition, their electrochemical properties and applications in the field of supercapacitors are demonstrated.

Supercapacitor technology encompasses a wide field of research that has already marked its foot in commercialization, just after some initial years of concept development.

QDs-Co₉S₈/CoNi-LDH was assembled by selective sulfurization derived from 2D MOF with the loading of Co₉S₈ quantum dots into layered double hydroxides. The constructed hybrid supercapacitor shown energy density of 33.3 Wh kg⁻¹ at 820.0 W kg⁻¹.

This work develops a facile anodic treatment process to prepare dispersed buckypaper tape for the highly efficient utilization of polypyrrole towards durable flexible energy storage.

The aggregation and self-stacking of MXenes and layered double hydroxides (LDHs) in the electrode preparation process are considered the primary obstacles to their practical applications.

Solvent-free, deep eutectic system-assisted synthesis of hierarchical porous carbons for high rate and high energy density supercapacitors.

Fe doping promotes the formation of high valence Ni^(3+δ)+, promoting the two-step reaction that improves energy storage.

Tailoring the characteristics of AsXBr/AsYBr ((X ≠ Y) = S, Se and Te) Janus heterostructures for advanced supercapacitor applications.

A hydrothermal reaction was employed to design CoS₂-based metal carbide hybrids. The assembled device offered 423 F g⁻¹ capacitance and 150 W h kg⁻¹ energy density along with a notable HER performance under acidic and KOH media for CoS₂-W₂C.

Gel electrolyte-based wearable all-sulfide semi-solid-state supercapacitor (ASSSC) device with ∼100% capacitance retention across the 40 000 charge–discharge cycles. The ASSSC devices are attached to human fingers to power electronic gadgets.

A straightforward hydrothermal process followed by thermal treatment is developed for constructing Fe-doped Co₃O₄ nanosheet floral clusters, which exhibit excellent electrochemical performance as supercapacitor electrodes.

Fe doping in the NiS lattice leads to an increase in the density of states near the Fermi level and thus to improved charge storage.

One-step solvothermal method is used to produce Ni_0.7Co_0.3-LDH intercalated with acetate. The incorporation of Co and acetate regulates pore size distribution and heterogeneous electron configuration, facilitating ion diffusion and redox activity.

We designed an “all-in-one” polypyrrole pillar hybridization flexible membrane for wearable energy-storage devices and human–machine interfaces (HMIs).

The valence and coordination structure of transition metals in electrode materials play a crucial role in the electrochemical energy storage process.

A facile in situ “growth–conversion–oxidation” strategy is employed to fabricate a core–shell structured CoO@Ov-NiCo LDH with abundant oxygen vacancies, which significantly improves the electrochemical performance.

A material structure design with 3D fast ion and electron diffusion channels for flexible supercapacitors with a high volumetric energy density.

Herein, a simple electric field-induced anion exchange process was raised to prepare a novel nanostructured CuCo₂S_x(OH)_y heterostructure based on CuCo₂S₄ nanosheets as a substrate.

Attributed to the strong synergy between S and oxygen vacancies, as well as the adjustable electrochemical behavior, the prepared bifunctional electrode exhibited superior OER and capacitive performance.

A novel quasi-solid-state integrated photo-capacitor (IPC) with flexible PEDOT/RGO film as a common electrode will improve carrier migration and the excellent overall conversion efficiency (arrive at 5.8%) of IPC.

Raspberry-like CuCo₂S₄@ZnS hollow particles encapsulated with reduced graphene oxide are synthesized for hybrid supercapacitors.

The conductive polymer PANI was coated on the surface of POM-based electrodes by the method of electrodeposition for improving the capacitive performance, and the corresponding solid-state SCs exhibited excellent capacitive performance.

A novel and conjugated 2D 250-HADQ COF exhibits a high specific surface area and excellent thermal stability yielding high values of gravimetric capacitance and energy density in two-electrode double-layer supercapacitor cells.

A hollow NiPSC electrode with a large d-spacing lattice distance has been demonstrated as an active SC electrode in a supercapacitor–battery hybrid device to achieve superior electrochemical performance.

The assembled hybrid supercapacitor device using the urea-based nickel molybdenum phosphate nanopetals embedded microspheres electrode exhibits outstanding long-term cycling stability, demonstrating its practical applications.

NiCo-LDH nanocages with high specific capacity, energy densities and good capacity retention are prepared with a Cu₂O template etching method.

The N doped porous carbon and ZrO₂ composite (NC@ZrO₂) with a synergistic pseudocapacitive effect provides abundant active sites for zinc ions and favors fast ion diffusion, ensuring remarkable rate performance and long cycling stability.

A new strategy has been designed for enhancing the electrochemical performances of supercapacitor electrodes.

Co-doped manganese dioxide was fabricated for an aqueous magnesium ion hybrid supercapacitor, showing excellent energy density and long-term cycle life.

Supercapacitors (SCs) coupled with redox materials have been extensively investigated to maximize the energy density of SCs.

Porous β-Ni(OH)_x–SO₄ interlaminar material has been prepared with an expanded interplane spacing and in-plane porous channels, which exhibits advanced supercapacitor property with a high specific capacity of 212.5 mA h g⁻¹ at 3 A g⁻¹.

An advanced hybrid supercapacitor with excellent electrochemical features was assembled using N,S co-doped porous carbon sphere decorated CoS nanoparticles with phosphate functionalization and ultrafine Fe₂O₃ nanocrystals.

ZIF-67/PBA heterostructure composites was prepared by the ion-exchange method with ZIF-67 nanoparticles as host MOFs. The electrochemical performance of the ZIF-67/PBA heterostructure composites improved after low-temperature calcination.

Two 3D POM-based metal–organic frameworks were prepared, which can be applied as electrode materials for supercapacitors, as well as efficient heterogeneous catalysts for the selective oxidation of sulfides to their corresponding sulfoxides.

A novel core–shell nanocluster NCOSe/Ni₂Co₁-LDH was constructed with excellent electrochemical properties. Moreover, the assembled HSC achieves an extremely high energy density of 89.7 Wh kg⁻¹ at a power density of 800 W kg⁻¹.

A green, versatile, and universal H₂O₂ activation method is proposed to improve the capacitive properties of high-mass loading wood-based supercapacitors.

We explored a new class of binder-free Mn doped Ni-based MOFs nanosheets through a polarity-induced solution-phase method for HSCs. The relationship between the electronic structure and the electrochemical activity has been further identified.

The accumulation and self-aggregation of nanosheets have been effectively inhibited. The interlamellar cobalt hydroxide nanostructures ensure efficient electron transfer. MXene as a conductive substrate improves electron transfer significantly.

Hierarchical core–shell electrode of PEDOT and MnO_x decorated SiNWs was developed through a simple, facile and low-temperature method, which displayed an excellent areal capacitance of 352.08 mF cm⁻².

(Ni/Co)_1−xS sub-nanoparticle-functionalized Co/Ni-LDH hollow nanocages (S-CNV-LDH) are prepared using a VO₃⁻-induced S²⁻-exchange strategy, which presents an enhanced supercapacitor performance.

V-ZnCo₂O₄/Ni composites with rich oxygen vacancies are designed through a hydrothermal method followed by post calcination and reduction. This strategy enhanced electrical conductivity, modulated electronic structure, and increased active sites.

N, P, S-Doped petal-like and cube-like C–(Mn₂O₃)₃MnSiO₃ are derived from reed leaves and used in supercapacitors.

Lead-free nickel–iron layered-double hydroxide (NiFe LDH) nanomaterial is used to fabricate a self-powered unit based on a piezoelectric nanogenerator and high-performance asymmetric supercapacitor (ASC).

The reasonable design of electrode materials is crucial for tuning the electrochemical performances of advanced energy storage systems.

Hierarchical Ni(OH)₂–MnO₂ hollow spheres are prepared via a simple self-templating route. The structural and compositional advantages of the Ni(OH)₂–MnO₂ material endow it with remarkable performance as a supercapacitor.

Nickel-based phosphide hollow nanotubes were constructed using a template strategy. The introduction of PANI may lead to the formation of C–Ni bonds or C–Ni–P bonds at the electrode interface, which induces electron transfer and improves the electrochemical capacity.

A hybrid consisting of Fe₃O₄ and MnO₂ with hollow structures was synthesized, and was demonstrated to be an efficient electrode for supercapacitors.

We report a strategy to synthesize Co-MOF-based hierarchical micro/nanospheres with ultrathin nanosheet subunits. Benefitting from the unique 3D architecture, the Co-MOF/M2 exhibits a high specific capacitance and excellent rate capability.

The synthesis procedure of the N-doped PC-CDs composite and the electrochemical reaction of iodide at the PC-CDs surface.

This work fabricates mechanically exfoliated graphite paper with layered microstructures, which not only ensures the high flexibility of the resulting electrochemical capacitor, but substantially boosts its electrochemical properties.

Magnesium ion supercapacitor assembled by MoS₂ with expanded layer spacing as the anode displays larger capacitance and excellent long-term cycling stability.

Microequilibrium transformation of micelles and vesicles assembled by ionic liquid surfactants enables the precise structural design and controlled synthesis of carbon micro/nanospheres, which can be used for high-performance supercapacitor electrodes.

NiCo₂O₄@NiMoO₄ core–shell nanowires (NCNMW) and nanosheets (NCNMS) with high electrochemical capabilities were synthesized using a simple two-step hydrothermal reaction, together with a calcination process.

In this study, nickel-bound porous carbon (Ni-PC) was prepared by introducing Ni²⁺ into dipotassium ethylenediaminetetraacetate (EDTA-2K) derived nitrogen-doped porous carbon (PC) using the ball milling method.