Electrodeposition of Manganese-Nickel-Cobalt Sulfides on Reduced Graphene Oxide/Nickel Foam for High-Performance Asymmetric Supercapacitors

Ternary metal sulfides are potential and attractive materials for supercapacitors. Manganese-nickel-cobalt ternary sulfide (MNCS) nanosheets deposited on reduced graphene oxide/nickel foam (rGO/NF) have been synthesized via a simple electrochemical approach. The obtained ternary metal sulfide (MNCS@rGO/NF) showed better electrochemical performance than corresponding bimetal nickel-cobalt sulfides on reduced graphene oxide/nickel foam (NCS@rGO/NF), which can be attributed to the addition of manganese to increase the oxidation state in the electrodes. The MNCS@rGO/NF electrode material achieved a significant specific capacitance of 1302 F g −1 at 0.5 A g −1 , with good rate performance and cyclic stability. In addition, asymmetric supercapacitor devices using the MNCS@rGO/NF and rGO/NF as positive and negative electrodes were fabricated, delivering high energy density of 103.62 Wh kg −1 at power density of 562.47 W kg −1 and 39.93 Wh kg −1 at power density of 1514.78 W kg −1 .