High stability of LiCoO2 enabled by mixed conductor Li0.33La0.557Ti0.8Cr0.2O3 coating.

LiCoO 2 has excellent volume energy density, and is the dominant cathode materials for 3 C electronic products. However, the capacity of LiCoO 2 is not fully utilized, and its cycle stability is not high enough. To preserve the structural stability of LiCoO 2 at high voltage, the mixed ion-electron conductor Li 0.33 La 0.557 Ti 0.8 Cr 0.2 O 3 is coated on LiCoO 2 particles, and the effects of coating amount and annealing temperature on the electrochemical performances are systematically investigated. The capacity retention of the pristine LiCoO 2 in the range of 2.8–4.5 V is only 51.0% after 200 cycles, which is related to the resistance increase of interface and cracks of cathode particles. The coating layer can improve the interface stability and keep the particles intact, and therefore, the capacity retention of the coated sample is significantly increased to 88.2%. • Mixed electron-ion conductor Li 0.33 La 0.557 Ti 0.8 Cr 0.2 O 3 is chosen as coating layer of LiCoO 2. • The coating material is coated on LiCO 2 particles by coprecipitation method. • The hard shell can maintain the particle integrity of LiCoO 2. • The coated particles have excellent cycle stability and rate performance. [ABSTRACT FROM AUTHOR]