Construction of hierarchical ZnCo2O4@CoSe core–shell nanosheets on Ni foam for high-performance supercapacitor

Hierarchical ZnCo2O4@CoSe core–shell composite electrode grown on Ni Foam (NF) was synthesized by hydrothermal method and electrochemical deposition method. No use of binder reduced the resistance of the electrode material. The addition of CoSe not only improves the conductivity of ZnCo2O4, but also forms a unique core–shell structure with ZnCo2O4. This core–shell structure provides some help for the improvement of electrochemical performance. The electrode material showed a specific capacitance of 1684.2 F/g (under 1 A/g) and cycle stability of 85.3% capacitance retention after 5000 cycles. Asymmetric supercapacitors fabricated by ZnCo2O4@CoSe/NF and activated carbon could reach an energy density of 58.44 Wh/Kg at power density of 763.32 W/Kg.