Rational Design of Hierarchically Core-Shell Structured Ni3 S2 @NiMoO4 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 Ni3 S2 @NiMoO4 nanowires (NWs) as a binder-free electrode for asymmetric supercapacitors. Due to the intimate contact between Ni3 S2 and NiMoO4 , the hierarchical structured electrodes provide a promising unique structure for asymmetric supercapacitors. The as-prepared binder-free Ni3 S2 @NiMoO4 electrode can significantly improve the electrical conductivity between Ni3 S2 and NiMoO4 , and effectively avoid the aggregation of NiMoO4 nanosheets, which provide more active space for storing charge. The Ni3 S2 @NiMoO4 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 Ni3 S2 @NiMoO4 //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.