Effects of Anisotropy in Rutile TiO₂ on the Performance of Solid-State Lithium Batteries

Rutile TiO2 is a promising electrode material for Li-ion secondary batteries. It has been theoretically predicted that rutile TiO2 exhibits anisotropy in the Li-ion diffusion coefficients, which may impact the battery performance. Consequently, to improve the battery performance, the effect of the anisotropy of Li-ion diffusion on battery performance must be clarified. Here, we quantitatively discuss the influence of the crystal orientation of rutile TiO2 on battery performance, in particular, on internal resistance. Li batteries were fabricated using rutile TiO2 epitaxial films with two orientations: (100) and (001). The results indicate that the (001)-oriented crystal exhibits a high battery performance with a low resistance at the interface of the solid electrolyte and electrode.