Effect of sol composition on solid electrode/solid electrolyte interface for all-solid-state lithium ion battery

A property of interface between solid electrode and solid electrolyte is one of the most important keys to fabricate all-solid-state lithium ion battery. In this study, an influence of sol composition used for preparation of the electrode on the property of interface between electrode and electrolyte was examined. LiMn₂O₄/honeycomb Li_0.55La_0.35TiO₃ (LLT) and Li₄Mn₅O₁₂/honeycomb LLT half cells were fabricated by impregnation of mixture of active materials with various precursor sols into honeycomb holes. In the case of LiMn₂O₄ cathode, the sol composed of nitrate salt provides large contact area of LiMn₂O₄ and LLT, resulting in higher performance of the cell. Li₂MnO₃ impurity was produced at Li₄Mn₅O₁₂/LLT interface prepared by the precursor sol composed of only nitrate or acetate salts although no impurity phase was observed at the interface prepared by acetate–nitrate sol containing lithium acetate and manganese nitrate. Li₄Mn₅O₁₂/honeycomb LLT half cell prepared by the acetate–nitrate sol showed the best performance among them. It is concluded that composition of the precursor sol strongly influenced on the interface of electrode and electrolyte. The all-solid-state Li ion battery composed of LiMn₂O₄/honeycomb LLT/Li₄Mn₅O₁₂ was successfully operated and the discharge capacity was 32 μAh cm⁻².