The film growth and electrochemical properties of rf-sputtered LiCoO2 thin films

In this work, the effect of various sputtering parameters (such as working pressure, O2 fraction, and rf power) on the film growth of HT-LiCoO2 on Pt-coated silicon were investigated. The as-deposited films and annealed films show crystalline HT-LiCoO2 single phase with (1 0 4) preferred orientation under various sputtering parameters. From ICP results, it was observed that the sputtering parameters and annealing process affected the compositions of the films obviously. The annealing process enhanced the crystallinity of HT-LiCoO2 films. They showed difference in crystallinity and resulted in the variation of Li+ diffusion coefficient that was measured and estimated by slow-scan-rate cyclic voltammetry (SSCV) and galvanostatic intermittent titration technique (GITT) techniques. The charge/discharge tests indicated that films exhibit higher DLi+DLi+ showed better rate capability.