Rational Design of Hierarchically Core–Shell Structured Ni3S2@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 Ni3S2@NiMoO4 nanowires (NWs) as a binder-free electrode for asymmetric supercapacitors. Due to the intimate contact between Ni3S2 and NiMoO4, the hierarchical structured electrodes provide a promising unique structure for asymmetric supercapacitors. The as-prepared binder-free Ni3S2@NiMoO4 electrode can significantly improve the electrical conductivity between Ni3S2 and NiMoO4, and effectively avoid the aggregation of NiMoO4 nanosheets, which provide more active space for storing charge. The Ni3S2@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 Ni3S2@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. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim