TiO₂ Anode Material for All-Solid-State Battery Using NASICON Li_1.5Al_0.5Ge_1.5(PO₄)₃ as Lithium Ion Conductor (Supporting Information)

We have been developing sintered multilayer oxide-based all-solid-state batteries. Anode active material rutile-type TiO₂ was not reacted with amorphous Na superionic conductor (NASICON)-type solid electrolyte Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) even after sintered at 600 °C in a nitrogen atmosphere from the XRD patterns. The charge/discharge behavior of the electrochemical measuring cell (when using a non-aqueous electrolyte) was not different from that of rutile-type TiO₂. However, anatase-type TiO₂ charge/discharge behavior changed after sintering process. Additionally, in the result of the input/output characteristics using multilayer oxide-based all-solid-state battery, rutile-type TiO₂ as anode material was 3 times higher discharge capacity than anatase-type TiO₂ at current value 25.6 µA mm⁻². Finally, we successfully measured the Raman spectroscopy of all-solid-battery and rutile-type TiO₂ Raman shift peaks were reversibility during charge/discharge. Based on these findings, we conclude that rutile-type TiO₂ maintained a strong crystalline structure and high Li diffusivity even when sintered with amorphous LAGP. It suggested that rutile-type TiO₂ is suitable as anode material for oxide-based all-solid-state batteries requiring the sintering process.