Enhanced electrochemical performance of surface modified LiCoO2 for all-solid-state lithium batteries

Li2CO3-coated LiCoO2 powders are prepared from a lithium hydroxide solution via low-temperature heat treatment and the effects on the electrochemical performance of all-solid-state lithium ion batteries (ASS-LIBs) using Li2S-P2S5 glass-ceramic solid electrolytes are investigated. A combination of X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analyses reveals that the Li2CO3 particles on the surface of LiCoO2 particles are formed without significant change in LiCoO2 structure. While the Li2CO3 is regarded as an impurity phase in lithium battery systems using liquid electrolytes due to its detrimental effects on electrochemical performance, we show that optimal amounts of Li2CO3 coating effectively suppress interfacial side reactions without a significant decrease in interfacial kinetics for all-solid-state lithium battery systems using sulfide solid electrolytes.