Li-ion diffusion kinetics in LiCoPO4 thin films deposited on NASICON-type glass ceramic electrolytes by magnetron sputtering

LiCoPO₄ thin films were deposited on Li_1+x+yAl_xTi_2−xSi_yP_3−yO₁₂ (LATSP) solid electrolyte by radio frequency magnetron sputtering and were characterized by X-ray diffraction and scanning electron microscope. The films show a (1 1 1) preferred orientation upon annealing and are chemically stable with LATSP up to 600 °C in air. An all-solid-state Li/PEO₁₈-Li(CF₃SO₂)₂N/LATSP/LiCoPO₄/Au cell was fabricated to investigate the electrochemical performance and Li-ion chemical diffusion coefficients, , of the LiCoPO₄ thin films. The potential dependence of values of the LiCoPO₄ thin film was investigated by potentiostatic intermittent titration technique and was compared with those of the LiFePO₄ thin film. These results showed that the intercalation mechanism of Li-ion in LiCoPO₄ is different from that in LiFePO₄.