Li-ion transport in all-solid-state lithium batteries with LiCoO2 using NASICON-type glass ceramic electrolytes

LiCoO2 thin films were deposited on the NASICON-type glass ceramics, Li1+x+yAlxTi2−xSiyP3−yO12, by radio frequency (RF) magnetron sputtering and were annealed at different temperatures. The as-deposited and the annealed LiCoO2 thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). It was found that the films exhibited a (1 0 4) preferred orientation after annealing and Co3O4 was observed by annealing over 500 °C due to the reaction between the LiCoO2 and the glass ceramics. The effect of annealing temperature on the interfacial resistance of glass ceramics/LiCoO2 and Li-ion transport in the bulk LiCoO2 thin film was investigated by galvanostatic cycling, cyclic voltammetry (CV), potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS) with the Li/PEO/glass ceramics/LiCoO2 cell. The cell performance was limited by the Li-ion diffusion resistance in Ohara/LiCoO2 interface as well as in bulk LiCoO2.