MnO2-wrapped hollow graphitized carbon nanosphere electrode for supercapacitor

• MnO2/HGC nanospheres are prepared by a cooperative template wrapping method.
• MnO2/HGC nanospheres possess large specific surface area.
• MnO2/HGC nanospheres are benefit for transmission of ions and electrons.
• MnO2/HGC electrodes exhibit a high specific capacitance.

MnO2-wrapped hollow graphitized carbon nanospheres (MnO2/HGC) electrodes are prepared by a cooperative template wrapping method. hollow Graphitized carbon nanospheres (HGC) are firstly obtained by carbonizing phenolic resin followed by etching the SiO2 template, then the MnO2 ultrathin nanoplates are coated on the surfaces of the HGC nanospheres through a redox reaction between KMnO4 and HGC nanospheres. The as-prepared MnO2/HGC hollow nanospheres possess porous structure and large specific surface area (∼230 m2 g−1). The specific capacitances of MnO2/HGC nanosphere electrodes with different mass ratios of MnO2 to HGC are about 340–380 F g−1 at a scan rate of 5 mV s−1 in Na2SO4 solution, and shows relative good cycling performance of the initial capacitance after 1000 cycles. The good specific capacitance is ascribed to the novel hollow nanosphere structure, which possesses high surface-to-volume ratio, and makes it easy for the mass diffusion of electrolyte and transmission of ions and electrons and also maintains the mechanical integrality.

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