Producing "Symbiotic" Reduced Graphene Oxide/MnO Nanocomposites Directly from Converting Graphite for High-Performance Supercapacitor Electrodes.

Almost all existing methods for preparing reduced graphene oxide/MnO (RGO/MnO) composites are based on the synthetized graphene or graphene oxides (GO), which make them complicated and high-cost processes. Here, we reported a new method, which is able to convert graphite directly to RGO/MnO composites. Thus, it is simpler, more economical, and productive. The structure of RGO/MnO inheriting intermediate product GO/MnO composites that are formed by the present method is a novel three-dimensional "multilayer steamed bread" nanostructure, which constitutes mutually beneficial "symbiosis". The nano-MnO supports the space between RGO layers and further to the combination of RGO to self-assemble into large-sized (>40 μm) nanocomposites. Meanwhile, the formed MnO particles were small (60 × 10 nm) in diameter and distributed homogeneously without the use of any template and surfactant. Because the structure and nanosize of composite cause the excellent electrochemical properties, RGO/MnO electrodes deliver an enhanced specific capacitance of 438.7 F/g at 0.3 A/g and outstanding cyclic stability (77.5% of its initial capacitance is retained after 1000 cycles).