Solvothermal synthesis of CoS2–graphene nanocomposite material for high-performance supercapacitors

A CoS2–graphene nanocomposite was prepared by a facile solvothermal method. FESEM and TEM analyses have confirmed that CoS2 nanoparticles with sizes of 5–15 nm are densely anchored on graphene nanosheets. The as-prepared nanocomposite was electrochemically tested as an electrode material for supercapacitors. The CoS2–graphene nanocomposite exhibited specific capacitances of 314 F g−1 in the aqueous electrolyte and 141 F g−1 in the organic electrolyte at a current rate of 0.5 A g−1 with excellent cycling stability. The electrochemical performance of the nanocomposite has been significantly improved, compared to bare graphene nanosheets and CoS2 nanoparticles. This could be credited to the 3D nanoarchitecture, in which CoS2 nanoparticles were sandwiched between graphene nanosheets, and the additional electrochemical contribution of the decorated CoS2 nanoparticles.