Facile and controllable synthesis of sea urchin-like CuCo2O4 on Ni foam for high-performance supercapacitors†

Abstract

CuCo₂O₄ is considered to be an attractive electrode material for supercapacitors due to its low toxicity, high theoretical capacity and low cost. However, the low specific capacity, poor cycling performance and low intrinsic conductivity limit the further application of CuCo₂O₄. In this research, CuCo₂O₄ arrays with different morphologies (rods, sea urchin-like and flakes) were synthesized on the surface of nickel foam (NF) via a solvothermal method and calcination. The controllable preparation of CuCo₂O₄ morphology was achieved by changing the solvent. Vertically grown sea urchin-like CuCo₂O₄ has large open channels that promote rapid electron transport, and the abundance of active sites allows more electrochemical reactions to occur simultaneously. As a result, the sea urchin-like CuCo₂O₄ exhibited the best electrochemical performance with a specific capacitance of 1426.2 F g⁻¹ at 1 A g⁻¹ and a capacitance retention of 96.78% after 10 000 cycles at 10 A g⁻¹. In addition, an asymmetric supercapacitor with a CuCo₂O₄ anode and a reduced graphene oxide (RGO) cathode was fabricated. At a power density of 802.3 W kg⁻¹, the CuCo₂O₄//RGO device exhibited an energy density of 59.6 W h kg⁻¹. This research provides insights into modulating the morphostructure of CuCo₂O₄ to improve its electrochemical properties.