A porous spherical aggregation of Li4Mn5O12 nanorods and its electrochemical performance

A porous spherical aggregation of Li4Mn5O12 nanorods with the particle size of 3 μm is prepared by oxidizing LiMn2O4 powder with (NH4)2S2O8 under hydrothermal conditions. The result displays that concentration of (NH4)2S2O8 plays a key role in forming the porous spherical aggregation and the optimal concentration of oxidant is found to be 1.5 mol L−1. The mechanism for the formation of the porous spherical aggregation is proposed. The electrochemical capacitance performance is tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge. The porous spherical aggregation exhibits a good electrochemical performance. It could deliver 375 F g−1 within potential range 0–1.4 V at a scan rate of 5 mV s−1 in 1 mol L−1 Li2SO4 and the value is cut down to less than 0.024 F g−1 per cycling period in 1000 cycles.