Electrochemical performances investigation of new carbon-coated nickel sulfides as electrode material for supercapacitors

Abstract

Anew carbon-coated nickel sulfides electrode material (NST/CNTs@C) has been synthesized through an easy-to-operate process: NiS2/CNTs which was prepared by a hydrothermal method reacted with BTC (1,3,5-benzenetricarboxylic acid) under the condition of water bath heating to obtain the precursor, and then the precursor was calcined in 450 °C under a nitrogen atmosphere to obtain NST/CNTs@C. The electrochemical performance of NST/CNTs@C has been greatly improved because the formation of a carbon-coated layer effectively increased the specific surface area, reduced the charge transport resistance and inhibited the morphological change of nickel sulfides in the charge-discharge process. Compared with pure NiS2 and NiS2/CNTs, NST/CNTs@C presented great specific capacitance (620 F·g-1 at a current density of 1 A·g-1), better cycle stability (49.19% capacitance retention after 1000 cycles) and more superior rate capability (when the current density was raised to 10 A·g-1 the specific capacitance remained 275 F·g-1).