Facile synthesis of low-defect-density graphene/MnO2 composite and its electrochemical performance

A facile chemical strategy was developed to anchor MnO2 nanoparticles on the surface of graphene sheet. Compared with literature, this approach requires neither extra pretreatment of acid functionalization of graphite nor any post-treatment for the conductivity compensation. Graphene sheet serves as both the nucleation center of the MnO2 nanoparticles and high-efficiency miniature current collectors, endowing an effective rise in electrochemical performance of the overall system. Meanwhile, few layers graphene restrain the aggregation of MnO2 nanoparticles and act as template for the "sandwich structure," which boosts accessible surface areas for the high rates charge and discharge processes. The internal resistance drops of the electrode were small, which is propitious to the high discharge delivery. And the nanocomposite with the unique structure displayed a specific capacitance as high as 340.5 F g(-1). Moreover, the capacitance decrease was only 3.7% after 1000 cycles.