Enhanced cycle stability of LiCoO2 at high voltage by mixed conductive Li7.5La3Zr1.5Co0.5O12 coating

Although LiCoO2 (LCO) has been commercialized, the capacity of its practical application is only 140 mAh g−1, which is half of the theoretical capacity due to the low cut-off voltage. When operated at high voltage, structural integrity, chemical stability, and phase stability are severely challenged, resulting in rapid capacity fading. The electrochemical performances can be significantly improved by surface coating. Mixed conductive Li7.5La3Zr1.5Co0.5O12 is coated on the LCO particles by the co-precipitation method. The cells are cycled in the voltage range of 2.8–4.5 V at 1C. After 200 cycles, LCO can only maintain 70.5% of its initial capacity, and in contrast, the capacity retention of coated LCO is as high as 96.1%. The particles of pristine LCO have been fractured or pulverized after 200 cycles, while the structural integrity of coated LCO particles is maintained.