Self-supported NiSe@Ni 3 S 2 core-shell composite on Ni foam for a high-performance asymmetric supercapacitor

In this work, NiSe@Ni 3 S 2 core-shell composite material was prepared with Ni foam as a substrate. Due to their unique structure, the NiSe@Ni 3 S 2 composite shows a superior specific capacitance of 1215 F g −1 , which is better than pure NiSe. Meanwhile, the NiSe@Ni 3 S 2 electrode demonstrates a wonderful cycling performance with 91.25% retention after 5000 cycles. The positive electrode materials and the negative electrode materials were designed employing the asymmetric supercapacitor (ASC) and the activated carbon (AC), respectively (ASC was created using NiSe@Ni 3 S 2 composite).When the optimal potential window of 1.8 V and the power density of 839 W kg −1 , the maximum energy density of 38 W h kg −1 was reached. In addition, after 5000 charge-discharge cycles, the NiSe@Ni 3 S 2 /NF//AC ASC devices exhibit a favorable cycling performance of 81.8% capacitance retention. These outstanding electrochemical performances demonstrate feasible testimony to verify that the NiSe@Ni 3 S 2 composite shows unlimited latent force at the research field of energy storage devices in the future.