Rational Design of Hierarchically Core–Shell Structured Ni 3 S 2 @NiMoO 4 Nanowires for Electrochemical Energy Storage

Rational design and controllable synthesis of nanostructured materials with unique microstructure and excellent electrochemical performance for energy storage are crucially desired. In this paper, a facile method is reported for general synthesis of hierarchically core–shell structured Ni 3 S 2 @NiMoO 4 nanowires (NWs) as a binder‐free electrode for asymmetric supercapacitors. Due to the intimate contact between Ni 3 S 2 and NiMoO 4 , the hierarchical structured electrodes provide a promising unique structure for asymmetric supercapacitors. The as‐prepared binder‐free Ni 3 S 2 @NiMoO 4 electrode can significantly improve the electrical conductivity between Ni 3 S 2 and NiMoO 4 , and effectively avoid the aggregation of NiMoO 4 nanosheets, which provide more active space for storing charge. The Ni 3 S 2 @NiMoO 4 electrode presents a high areal capacity of 1327.3 µAh cm −2 and 67.8% retention of its initial capacity when current density increases from 2 to 40 mA cm −2 . In a two‐electrode Ni 3 S 2 @NiMoO 4 // active carbon cell, the active materials deliver a high energy density of 121.5 Wh kg −1 at a power density of 2.285 kW kg −1 with excellent cycling stability.