In Situ Growth of 3D Nano‐array Ni0.85Se/NF Structure Supercapattery Electrode with Excellent Cyclic Stability and Superior Energy Density

Abstract

AbstractThe growth of three‐dimensional(3D) nano‐array Ni0.85Se structure on Ni foam (Ni0.85Se/NF) in situ by hydrothermal treatment using Na2SeO3⋅5H2O as Se source is presented in this article. Moreover, when fabricated as binder‐free supercapattery electrode, the 3D nano‐array Ni0.85Se/NF structure demonstrates an excellent specific capacitance of 1344 and 686.50 F⋅g−1 at current densities of 0.5 and 5 A⋅g−1, which was calculated by 4 mg active mass of Ni0.85Se. Impressively, the areal capacitance of 5.38 and 2.75 F⋅cm−2 can be got at the current densities of 2 and 20 mA⋅cm−2. Furthermore, the supercapattery electrode exhibits a superior cyclic stability with 70.1 % capacity retention after 5000 cycles, which is notable for a selenide based supercapacitor. When assembled into Ni0.85Se//AC asymmetric supercapacitor, the operating voltage was expanded to 1.6 V, a good specific capacitance of 184.70 C⋅g−1 at 0.5 A⋅g−1 and remains 35.33 C⋅g−1 at 4 A⋅g−1 is achieved. The supercapattery electrode demonstrates an outstanding rate performance as a coin type asymmetric device, obtaining a great energy density of 38.48 Wh⋅kg−1 at the power density of 375 W⋅kg−1. The aforementioned results suggested that the 3D nano‐array Ni0.85Se structure may a potential electrode for next generation supercapacitors.