Al2O3 Coated Li4Ti5O12 Electrode with Enhanced Cycle Performance for Lithium Ion Battery

Spinel Li4Ti5O12 anode was prepared by traditional doctor blade method. The as-prepared electrode was coated with a thin Al2O3 layer by a facile radio frequency (RF) magnetron sputtering afterwards. The structure and morphology were characterized by XRD and SEM. The electrochemical performance was collected by galvanostatic discharge-charge tests. The measuring potential range was between 0.01 V and 3.0 V. The reversible capacity was as high as 194 mAh/g when discharge/charged at a current density of 35 mA/g. The coating layer did not hinder the performance under high current density, showing the discharge capacity of 134 mAh/g at 175 mA/g. The capacity retention after 100 cycles at 88 mA/g is 91%, much higher than that of the pristine Li4Ti5O12 electrode. The greatly improved cycle stability was attributed to the reduced polarization and the enhanced integrity of the electrode structure.