Solvothermal synthesis of micro-/nanoscale Cu/Li4Ti5O12 composites for high rate Li-ion batteries

The micro-/nanoscale Cu/Li4Ti5O12 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 Li4Ti5O12 and the Cu nanoparticles dispersed in the matrix of Li4Ti5O12. As an anode material for rechargeable lithium-ion batteries, the Cu/Li4Ti5O12 composite with Cu content of 15 wt.% exhibited the better rate and cyclic performance than those samples of Cu/Li4Ti5O12 with Cu content of 0 wt.%, 3.75 wt.%, 7.5 wt.%, 22.5 wt.%. The initial discharge capacity of Cu/Li4Ti5O12 composites with Cu content of 15 wt. % at 20 C 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/Li4Ti5O12 (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.