In Situ Growth of Core–Shell Heterostructure CePO4@CuCo2S4 As Advanced Electrodes for High-Performance Supercapacitor

The design of multicomponent core–shell heterostructures is considered to be an efficacious way to develop excellent performance supercapacitor electrode materials. A new strategy CePO4@CuCo2S4 core–shell heterogeneous structure is devised by preparing porous CePO4 nanosheets as cores via hydrothermal reaction and solid-state phosphating methods and electrochemically deposited CuCo2S4 nanosheets as shells. Binder-free three-dimensional (3D) porous CePO4@CuCo2S4 nanosheets grown on foam nickel substrate can provide an ordered porous nanoframe, promote electrode/ion transport, and generate the effective synergy of good conductivity from CePO4 and excellent redox activity from CuCo2S4. As a consequence, the CePO4@CuCo2S4 electrode exhibits an outstanding specific capacitance (2897.8 F g–1 at 0.5 A g–1), a superb capacity retention rate (70.1% at 20 A g–1), and excellent cycle stability (after 10,000 cycles or maintain 94.4%), superior to those of bare CePO4 and CuCo2S4 electrodes. In addition, an asymmetric hybrid supercapacitor is assembled by CePO4@CuCo2S4 and activated carbon, when the energy density is 80.4 Wh kg–1 and the corresponding power density is 799.5 W kg–1.