Preparation of nanoporous nickel[sbnd]copper sulfide on carbon cloth for high-performance hybrid supercapacitors

Abstract

In this work, nanoporous nickel-copper sulfide on carbon cloth was successfully prepared via sulfurizing the nickel-copper carbonate hydroxide precursor through an anion exchange reaction. The as-fabricated electrode exhibits a high specific capacitance of 938.6 F g−1 at a current density of 1 A g−1 and good rate capability of 76% at 10 A g−1, as well as excellent flexibility. Charge storage analysis demonstrates that the combination of surface-controlled capacitive process and diffusion-controlled Faradaic process, both contribute to the total capacitance. In addition, the good performance of the nanoporous nickel-copper sulfide can be attributed to the possible higher conductivity and porous nanostructures which offers more active sites to yield extrinsic pseudocapacitance. A hybrid supercapacitor was assembled with nickel-copper sulfide as the positive electrode and nitrogen-doped graphene as the negative electrode, delivering a high cell voltage up to 1.7 V with a maximum energy density of 35.3 Wh kg−1 and a maximum power density of 12700 W kg−1. A red round light-emitting diode (LED) was successfully illuminated by the pouch cell composed of two Ni0.8Cu0.2−S//NG HSCs. The high performance we achieved suggests that the nanoporous nickel-copper sulfide has deep potential for high-performance supercapacitor applications.