Enhanced cycling stability of microsized LiCoO2 cathode by Li4Ti5O12 coating for lithium ion battery

The effect of Li4Ti5O12 (LTO) coating amount on the electrochemical cycling behavior of the LiCoO2 cathode was investigated at the high upper voltage limit of 4.5 V. Li4Ti5O12 (≤5 wt.%) is not incorporated into the host structure and leads to formation of uniform coating. The cycling performance of LiCoO2 cathode is related with the amount of Li4Ti5O12 coating. The initial capacity of the LTO-coated LiCoO2 decreased with increasing Li4Ti5O12 coating amount but showed enhanced cycling properties, compared to those of pristine material. The 3 wt.% LTO-coated LiCoO2 has the best electrochemical performance, showing capacity retention of 97.3% between 2.5 V and 4.3 V and 85.1% between 2.5 V and 4.5 V after 40 cycles. The coulomb efficiency shows that the surface coating of Li4Ti5O12 is beneficial to the reversible intercalation/de-intercalation of Li+. LTO-coated LiCoO2 provides good prospects for practical application of lithium secondary batteries free from safety issues.