Morphology modulation of NiCo2S4 arrays in-situ growth on carbon cloth for high performance flexible supercapacitor electrode

Abstract

NiCo2S4 has been extensively researched as a promising pseudocapacitor material. In this work, NiCo2S4 with three different morphologies (nanoneedles, nanosheets and hexahedrons) were synthesized in-situ grown on the surface of carbon cloth by two-step hydrothermal method with adding different dosage of NH4F. The NH4F plays a key role in controlling the morphology of NiCo2S4 and the mechanisms for the effects of different dosage of NH4F on the morphology of NiCo2S4 are proposed. The electrochemical results show that NiCo2S4 nanosheets delivers the best performance with specific capacitance of 2.98 F cm−2 at 1 mA cm−2 and good cycling stability (82% retention at 20 mA cm−2 after 1000 cycles). In addition, the flexible supercapacitor fabricated with NiCo2S4 nanosheet and activated carbon possesses an energy density of 21.4 Wh kg−1 at a power density of 662.98 W kg−1. All these results indicate that NiCo2S4 nanosheet is an ideal potential electrode material for supercapacitors.