Dodecyl sulfate-induced fast faradic process in nickel cobalt oxide-reduced graphite oxide composite material and its application for asymmetric supercapacitor device

In this contribution, we report a facile preparation method of nickel cobalt oxide-reduced graphite oxide (NiCo ₂O ₄-rGO) composite material. A fast Faradic process has been realized by sodium dodecyl sulfate (SDS)-induced ultrasmall NiCo ₂O ₄ nanocrystals on rGO. As a result, this composite material gives a high specific capacitance of 1222 F g ^-1 at 0.5 A g ^-1 and 768 F g ^-1 at 40 A g ^-1, showing an outstanding rate capability. An asymmetric supercapacitor device with high energy and power densities has been successfully assembled based on NiCo ₂O ₄-rGO composite material and activated carbon. The optimized device shows a high energy density of 23.32 Wh kg ^-1 at a power density of 324.9 W kg ^-1. In addition, this asymmetric device shows good stability towards multistage current charge-discharge cycles.