Construction of hierarchical nickel cobalt sulfide@manganese oxide nanoarrays@nanosheets core‐shell electrodes for high‐performance electrochemical asymmetric supercapacitor

Abstract

Core-shell nanostructured three-dimensional binderless electrode porosity makes them ideal candidates for electrochemical energy storage applications. This article proposes NiCo2S4@MnOx electrodes fabricated using a facile hydrothermal approach and subsequently annealed at 120°C for 12 hours. The resultant [email protected] structure allows rapid ion and electron transport. Coating with pseudocapacitive MnOx on NiCo2S4 nanoarrays improves overall capacitance, and the amorphous MnOx nanosheets promote electrode cycling stability. The proposed NiCo2S4@MnOx electrode achieved excellent specific capacitance of 1640 F·g−1 at 5 mA·cm−2 and cyclic stability ≈ 90%; and the subsequently fabricated asymmetric electrochemical supercapacitor achieved specific capacitance ~96.91 F·g−1, and specific energy (SE) 26.38 Wh·kg−1 at specific power (SP) 466.66 W·kg−1, with impressive electrochemical stability ≈ 80% over 5000 charge/discharge cycles.