Self-Supported Ni0.85Se Nanosheets Array on Carbon Fiber Cloth for a High-Performance Asymmetric Supercapacitor

In this work, Ni 0.85 Se nanosheets array electrode material was prepared with carbon fiber cloth (CFC) as a substrate. Owing to their special structure, the Ni 0.85 Se nanosheets array exhibits an outstanding energy storage property with a superior specific capacitance (820 F/g) and great rate capability (83.17%). Moreover, the Ni 0.85 Se electrode presents an great cycling performance with 82.63% retention after 10,000 cycles. The asymmetric supercapacitor (ASC) was fabricated based on Ni 0.85 Se positive and activated carbon (AC) negative electrode materials, with KOH/PVA gel as the electrolyte, respectively. A highest energy density of 29 W h kg −1 was achieved at a power density of 779 W kg −1 under the optimal potential range of 1.6 V. Furthermore, the Ni 0.85 Se//AC ASC devices demonstrate a great cycling performance of 81.25% capacitance retention after 5000 charge–discharge cycles. These excellent performance provide strong evidence to confirm the conclusion that Ni 0.85 Se nanosheets array used as electrode materials in supercapacitors and Ni 0.85 Se//AC asymmetric supercapacitors hold significant potential in the field of energy storage.