▎ 摘　　要

An aqueous, high potential asymmetric supercapacitor (ASC) is developed using cobalt manganite (CoMn2O4) modified graphene nanoribbon (GNR). Combining CoMn2O4/GNR and GNR as different electrodes of supercapacitor in Na2SO4 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 84.69Wh Kg (1) (more than four times of the symmetric cell) at high power density 22kWKg (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. (C) 2014 Elsevier Ltd. All rights reserved.