▎ 摘　　要

Graphene/Mn3O4 composites were synthesized by a facile flash irradiation method at room temperature. The flash irradiating triggers the deoxygenation reaction of graphene oxide and the decomposition reaction of manganese nitrate. Additionally, the graphene/Mn3O4 positive electrodes showed a wide operating potential of 0-1.2V (vs SCE) in aqueous electrolyte for supercapacitors. The extended potential windows further expand the stable cell voltage (2.2 V) for aqueous asymmetric supercapacitors with a high energy density of 18.5Whkg(-1) at power density of 0.28kWkg(-1).