Solution combustion synthesis of nickel sulfide/reduced graphene oxide composite powders as electrode materials for high-performance supercapacitors

Nickel sulfide/reduced graphene oxide composite powders were prepared by solution combustion method using nickel nitrate and graphene oxide as oxidants together with thioacetamide, either alone or admixed with glycine, as fuel. Graphene oxide was in-situ reduced during combustion process. Phase, structure, and microstructure of the combusted powders were tuned by proper use of the type and amount of fuels. With the increase of glycine as an auxiliary fuel, bulky microstructures of sintered particles were appeared. The nickel sulfide/reduced graphene oxide composite powders showed the pseudocapacitive behavior with a high specific capacitance of 305 F g−1 at a current density of 1.1 A g−1. The high conductivity of reduced graphene oxide and distribution of nickel sulfide nanoparticles on reduced graphene oxide sheets led to the high capacity retention of 91% after 3000 cycles.