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

摘要

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. LiMn_2O_4/honeycomb Li_(0.55)La_(0.35)TiO_3 (LLT) and Li_4Mn_5O_(12)/honeycomb LLT half cells were fabricated by impregnation of mixture of active materials with various precursor sols into honeycomb holes. In the case of LiMn_2O_4 cathode, the sol composed of nitrate salt provides large contact area of LiMn_2O_4 and LLT, resulting in higher performance of the cell. Li_2MnO_3 impurity was produced at Li_4Mn_5O_(12)/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. Li_4Mn_5O_(12)/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 LiMn_2O_4/honeycomb LLT/Li_4Mn_5O_(12) was successfully operated and the discharge capacity was 32 μAh cm~(-2).