Hollow nanospheres comprising amorphous NiMoS4 and crystalline NiS2 for all-solid-state supercapacitors

Phase engineering offers a promising strategy to tailor the physiochemical properties to further improve their electrochemical performance toward energy storage. However, it remains a challenge to fabricate well-defined amorphous/crystalline hetero-phase metal sulfides with high-density heterointerfaces. Herein, the synthesis of hetero-phase combination of amorphous NiMoS4 and crystalline NiS2 that possesses hollow nanosphere structure decorated by nanosheets (named as H-NiMoS4/NiS2) is reported. Benefiting from the construction of the hollow nanosphere coated by nanosheets, amorphous/crystalline hetero-phase junction, and strong Ni-S hybridization, H-NiMoS4/NiS2 electrode exhibits high specific capacity, outstanding rate capability and excellent cycling stability. Moreover, an all-solid-state supercapacitor was assembled with H-NiMoS4/NiS2 as cathode and needle coke oxide (NCO) as anode, which can achieve remarkably high energy density of 38.6 Wh kg−1 at a power density of 958.6 W kg−1 and outstanding capacity retention of 83.7% after 20,000 cycling. The preparation of novel H-NiMoS4/NiS2 nanomaterial with a hetero-phase of amorphous and crystalline provides a new solution for improving the structural stability and capacitor storage performance as electrodes for supercapacitors.