Dry modification of electrode materials by roller vibration milling at room temperature

For the first time dry roller vibration milling at room temperature was used to prepare active carbon (AC) nano-particles and to modify MnO2 powder as electrode materials. In 30 min AC was milled to a mean particle size of 30–50 nm with increased crystallinity and higher specific surface area, predominantly mesoporous and with improved pore diameter distribution. Then, AC nano-particles were incorporated with MnO2 or bismuth-doped MnO2 nano-particles synthesized by sol–gel methods to prepare nano-composite electrode materials for studying their electrochemical performance. The AC nano-particles combined with 10 wt.% bismuth-doped MnO2 nano-particles were found to possess excellent electrochemical property with specific capacitance up to 308 F/g and without obvious attenuation with increasing current. Our method seems to open a new way to improve AC based electrode materials used for clean energy such as super capacitors.