Performance evaluation of Asymmetric Supercapacitor based on Cobalt manganite modified graphene nanoribbons

An aqueous, high potential asymmetric supercapacitor (ASC) is developed using cobalt manganite (CoMn sub(2)O sub(4)) modified graphene nanoribbon (GNR). Combining CoMn sub(2)O sub(4)/GNR and GNR as different electrodes of supercapacitor in Na sub(2)SO sub(4) electrolyte, the ASC device exhibited 1.9 V wide potential window for charge storage along with significantly improved capacitive performance than symmetric counterpart. When cycled reversibly in 0-1.9 V, the ASC demonstrates high energy density 84.69 Wh Kg super(-1) (more than four times of the symmetric cell) at high power density 22 kW Kg super(-1) due to elegant synergism between different electrodes. Additionally, it exhibits long term stable cycling performance with 96% capacitance retention and similar to 97.5% columbic efficiency. These outstanding results pave their way for promising applications in high energy storage systems.