High-performance supercapacitor based on a hierarchical core-shell CuCo2O4@ZnWO4/NF electrode materials with high specific capacitance

A hierarchical CCO@ZWO core-shell architecture was fabricated on nickel foam. • Binder-free CCO@ZWO/NF electrode delivers 3670 mF cm −2 at 1 mA cm −2 . • The CCO@ZWO/NF//AC/NF ASC retains 87.75% capacitance after 7800 cycles. • The ASC device achieves 0.198 mWh cm −2 at 0.75 mW cm −2 . One heavily relied-upon strategy for achieving advanced electrode materials with superior properties for asymmetric supercapacitors (ASCs) is the rational design of hierarchical core-shell heterostructures on conductive substrates. In this work, a well-defined urchin-like CuCo 2 O 4 @ZnWO 4 (CCO@ZWO) core-shell heterostructure was successfully fabricated on porous nickel foam (NF) via a simple two-step solvothermal process, followed by thermal annealing. The hierarchical structure is composed of CuCo 2 O 4 nanoneedles serving as the conductive core, with ZnWO 4 nanosheets uniformly anchored as the shell layer, which collectively provides an extensive specific surface area with a high density of electroactive centers and favorable ion/electron transport kinetics. With a binder-free architecture, the CCO@ZWO/NF composite delivers a high areal capacitance of 3670 mF cm −2 at a current density of 1 mA cm −2 , enabling the assembly of an asymmetric supercapacitor with CCO@ZWO/NF as the positive electrode and NF-supported activated carbon as the negative electrode. The device exhibited a cycling stability that was evaluated over 7800 cycles at 4 mA cm −2 , showing a capacitance preservation of 87.75%, while a capacitance per unit area of 633.7 mF cm −2 was obtained at 1 mA cm −2 . The remarkably improved electrochemical performance stems from the cooperation between the two components and the robust core-shell architecture, which effectively mitigates volume expansion and structural collapse during repeated cycling. These findings underscore the considerable promise of the designed CCO@ZWO core-shell heterostructure in serving as an advanced electrode material, offering a viable pathway for exceptional energy storage applications. A biomimetic urchin-like CuCo 2 O 4 @ZnWO 4 core-shell heterostructure was grown on nickel foam via a two-step solvothermal method with subsequent annealing. The hierarchical architecture provides a large specific surface area, abundant active sites, and fast ion/electron transport. The CCO@ZWO/NF electrode delivers a high areal capacity of 3670 mF cm −2 at 1 mA cm −2 , and the ASC device achieves an energy density of 0.198 mWh cm −2 with 87.75% retention after 7800 cycles. This superior performance stems from the synergistic interplay between the core-shell morphology and the multi-metal oxide composition. Download: Download high-res image (352KB) Download: Download full-size image