In-situ directly anchored CoMoS4 particles on reduced graphene oxide nanosheets for the high-efficiency asymmetric supercapacitor

The well-designed CoMoS 4 /reduced graphene oxide (RGO) composite was directly synthesized by a simple one-step hydrothermal method , in virtue of the uniformly-distributed oxygen-containing functional groups on the precursor graphene oxide (GO) surface. As expected, the optimized CoMoS 4 /RGO exhibits the high specific capacity of 123 mAh/g at 1 A/g, about 152% higher than that of pure CoMoS 4 . The reason is as follows: (1) the structure with no serious aggregation can be favor of rapid electrolyte ion transport process; (2) the RGO phase cannot only provide the high specific surface area, moderate conductivity and electrochemical double layer capacitance from the Π conjugated carbon skeleton, but also contribute to some extra Faradaic redox capacitance from a few oxygen-containing functional groups. As for practical application, the fabricated CoMoS 4 /RGO//AC asymmetric supercapacitor can deliver the good energy storage performances, such as the high energy density of 59 Wh/kg at 1125 W/kg (almost superior to the reported CoMoS 4 based asymmetric supercapacitor devices to our best knowledge), especially for the good cycle stability with 99.3% capacity retention after 6000 cycles. Therefore, this work can provide a feasible strategy to improve the supercapacitor performances of CoMoS 4 .