Simple synthesis of high-performance α-NiS particles as battery-type cathode material for advanced hybrid supercapacitor application

Abstract

Design and fabrication of electrode materials with superior properties is an effective way to improve the electrochemical performance of supercapacitors. In this study, pure α-NiS particles with different sizes were prepared via an easy hydrothermal method at 140 °C (NiS-140) and 160 °C (NiS-160), respectively, utilizing thioacetamide as a sulfur source. Both NiS-140 and NiS-160 electrode materials in traditional three-electrode system displayed the battery-type electrochemical response. At 1 A g⁻¹, the NiS-140 possessed an amazing specific capacity of 695.25C g⁻¹, while NiS-160 delivered a lower capacity of 578.25C g⁻¹. To investigate their application potential in the practical electrochemical energy storage, the hybrid supercapacitor (HSC) device was assembled using activated carbon (AC) as an anode and NiS-140 (NiS-160) as the cathode. The NiS-140//AC HSC can exhibit an outstanding energy density of 45.09 W h kg⁻¹ at 834.27 W kg⁻¹. Furthermore, the two NiS//AC HSCs displayed outstanding cyclic stability with respective 96.5 % and 95.6 % capacity retention after 5000 cycles under 10 A g⁻¹. This simple synthesis method and superior electrochemical characteristics of NiS provide a feasible and affordable path to the synthesis of other transition metal compounds for electrochemical energy storage.