Self-supported electrode based on two-dimensional NiPS₃ for supercapacitor application

Two-dimensional (2D) layered materials hold great promise for electrochemical energy storage due to their unique structure. It is always desirable to explore new-type high-performance 2D structured electrode materials in energy field. In this work, layered transition-metal chalcogenophosphite is developed as the electrode material for supercapacitors for the first time. NiPS₃ nanosheet arrays are successfully in-situ grown on carbon cloth via a chemical vapor deposition method, and then directly used as the self-supported electrode for supercapacitors. The fabricated carbon cloth supported NiPS₃ nanosheet arrays offer obviously superior electrochemical performance to the powdery NiPS₃ nanosheets sample. The self-supported NiPS₃ electrode exhibits a high specific capacitance of 1148F g^-1 at a current density of 1 A g^-1, and a good cycling stability with capacitance retention of 81.4% over 5000 cycles at 10 A g^-1. Moreover, the assembled asymmetric supercapacitor device delivers a specific capacitance of 61.3F g^-1 at a current density of 1 A g^-1, and an energy density of 19.2 Wh kg^-1 at a power density of 750 W kg^-1 with a voltage window of 1.5 V. This work is of great significance for pioneering the application of 2D transition-metal chalcogenophosphites in supercapacitors.