Mixed lithium ion and electron conducting LiAlPO3.93F1.07-coated LiCoO2 cathode with improved electrochemical performance

摘要

LiCoO2 (LCO) has been functionally modified by mixed lithium ion and electron conducting LiAlPO3.93F1.07 (LAPF) for the first time. Due to the unique coating layer with accepted Li-ion diffusion rate and electronic conductivity, the LAPF-coated LCO exhibits outstanding rate capability and cycle stability in the voltage range of 2.75-4.55 V. This material delivered a specific capacity of 206 mAh.g(-1) up to 0.5C rate and the capacity retention was 91.7% after 50 cycles, which is a remarkable improvement comparing with uncoated LCO (34.8%). It also exhibited superior rate capability with a discharge capacity of 161.4 mAh.g(-1) at 4C. The functionalized LAPF coating technique is an efficient approach to improve the electrochemical performance of LCO and can also be referred for other layered oxide cathode materials.