Flash-Induced Ultrafast Production of Graphene/MnO with Extraordinary Supercapacitance

Production of high-capacitance electrodes beyond the theoretical limit of 550 F g^-1 of pure graphene materials is highly desired for energy storage applications, yet remains an open challenge, especially with a facile and simple process. By rational design of reaction condition guided by theoretical analysis, the ultrafast (within millisecond) fabrication of high-performance graphene/MnO electrodes via a low-cost and one-step flash reduction process is proposed and demonstrated. This simple method enables high-quality porous graphene networks and the effective synthesis of embedding pseudocapacitive-active MnO nanomaterials simultaneously. Due to the high-density and homogeneous distribution of MnO nano-needles on 3D graphene networks, an ultrahigh capacitance (up to 1706 F g^-1 based on electrode mass and 2150 F g^-1 based on MnO mass only) is demonstrated. Functional supercapacitor prototype further illustrates the broad potential applications enabled by the fabricated electrodes in energy storage, sensing, and catalysts.