Solvothermal synthesis of micro-anoscale Cu/Li_4Ti_5O_(12) composites for high rate Li-ion batteries

摘要

The micro-anoscale Cu/Li_4Ti_5O_(l2) composites were prepared by a solvothermal method. The X-ray diffraction (XRD) and the transmission electron microscopy (TEM) images reveal that the addition of Cu has no effect on the crystal structure of spinel Li_4Ti_5O_(12) and the Cu nanoparticles dispersed in the matrix of Li_4Ti_5O_(12). As an anode material for rechargeable lithium-ion batteries, the Cu/Li_4Ti_5O_(12) composite with Cu content of 15 wt.% exhibited the better rate and cyclic performance than those samples of Cu/Li_4Ti_5O_(12) with Cu content of 0 wt.%, 3.75 wt.%, 7.5 wt.%, 22.5 wt.%. The initial discharge capacity of Cu/Li_4Ti_5O_(12) composites with Cu content of 15wt. % at 20C rate is 122.9 mAh/g and remains as high as 107 mAh/g after 1000 cycles (87% retention). Meanwhile, we did some comparable experiments, the results show that the Cu/Li_4Ti_5O_(12) (15 wt.%) composite also exhibits a good electrochemical performance even without the acetylene black. The enhanced performance for the composites (Cu 15 wt. %) is ascribed to the improved electronic conduction and the reduced polarization resulting from the appropriate Cu modification together with micro- and nanosized structure when used as an anode electrode material.