Constructing Ni–Co PBA derived 3D/1D/2D NiO/NiCo2O4/NiMn-LDH hierarchical heterostructures for ultrahigh rate capability in hybrid supercapacitors

Abstract

Engineering hierarchical heterostructure materials has been recognised as a challenging but prepossessing strategy for developing hybrid supercapacitors. Thus, a Ni–Co PBA derived 3D/1D heterostructure NiO/NiCo₂O₄ based layered double hydroxide on carbon cloth (CC/NiO/NiCo₂O₄/NiMn-LDH) as a battery-type electrode was successfully designed via a controllable hydrothermal method. The 3D Ni–Co PBA nanocubes served as scaffolds, providing more space for the nickel-cobalt precursors to grow and then calcine to form a continuous conductive layer of 3D/1D CC/NiO/NiCo₂O_4. Subsequently, 2D ultrathin NiMn-LDH nanosheets were uniformly anchored on 3D/1D NiO/NiCo₂O₄, resulting in a unique hierarchical structure that effectively addressed the restacking issue and dead volume of NiMn-LDH, contributing to increased charge and electron transport rates, which promoted the reaction kinetics. Benefiting from abundant interfaces with the open channels of the nanoarchitecture, the CC/NiO/NiCo₂O₄/NiMn-LDH electrode showed an exceptional specific capacity of 1593.0 C g⁻¹ at 1 A g⁻¹ and a desirable rate performance of 92.9% at a current density of 8 A g⁻¹. Surprisingly, HSC devices can achieve an ideal specific energy of 44.28 W h kg⁻¹ at a specific power of 108.22 W kg⁻¹ with 97.59% cycling durability after 10 000 consecutive charge/discharge cycles. These remarkable properties indicate that the designed novel hierarchical heterostructure electrode has great potential for broad applications in electrochemical energy storage systems.