High-rate Li4Ti5O12/C composites as anode for lithium-ion batteries

The Li4Ti5O12/C composites were synthesized by a simple solid-state reaction at 800 A degrees C for 12 h by using Super PA (R) conductive carbon black as carbon source. X-ray diffraction analysis shows that the Li4Ti5O12 with 0, 5, 7.5, and 10 wt% carbon shows similar patterns with cubic spinel structure. Scanning electron microscope shows that Li4Ti5O12 aggregated seriously, but the aggregation was inhibited by the addition of Super PA (R) carbon. The results indicate that the addition of 5 wt% carbon during sintering and a further 5 wt% carbon during slurry preparation shows the best rate capability of 110 mAh/g when the cells were charge/discharged at 10 C rate. The comparison of the charge-discharge curves shows that the higher rate improvement should further decrease the particle size of LTO or improve the conductivity of LTO itself.