A flexible and high-performance all-solid-state supercapacitor device based on Ni3S2 nanosheets coated ITO nanowire arrays on carbon fabrics

Abstract

A Ni₃S₂ coated indium tin oxide (ITO) core–shell structure on flexible carbon fabrics (CF@ITO@Ni₃S₂) was prepared by electrodepositing Ni₃S₂ nanosheets on ITO nanowire arrays grown on flexible carbon fabrics by chemical vapor deposition. The ITO nanowires on carbon fabrics formed a conductive support which offered a large contact surface with the electrolyte and hence was accessible for ion diffusion. Ni₃S₂ nanosheets were uniformly deposited on the ITO nanowire. The maximum mass loading of Ni₃S₂ on ITO nanowire array coated carbon fabrics could reach about a quadruple higher amount than that on the bare carbon fabrics. The prepared CF@ITO@Ni₃S₂ electrodes exhibited excellent capacitive performance compared with Ni₃S₂ coated bare carbon fabric electrodes (CF@Ni₃S₂). High areal capacitance of 3.85 F cm⁻² and gravimetric capacitance of 1865 F g⁻¹ were achieved when the mass loadings of Ni₃S₂ on the ITO nanowire arrays were around 4.12 mg cm⁻² and 0.96 mg cm⁻², respectively. The sample with 0.96 mg cm⁻² of Ni₃S₂ could also deliver 1372 F g⁻¹ when charge–discharge current density reached 50 mA cm⁻², indicating the excellent rate capability of the structure. The assembled all-solid-state full cell based on symmetric electrodes obtained a relatively high areal capacitance of 736 mF cm⁻² at 8 mA cm⁻², which delivered a maximum energy density of 1.02 mW h cm⁻³ at a power density of 39.9 W cm⁻³. The outstanding capacitive performance suggests that the CF@ITO@Ni₃S₂ device was promising for application in an inexpensive energy storage system.