2022 年 90 巻 6 号 p. 067003
Porous La2/3−xLi3xTiO3 (LLTO) for use as a Li ion conducting framework was prepared on sintered Li0.29La0.57TiO3 bodies using either polyvinylpyrrolidone-assisted sol-gel or screen-printing methods. A mixture of Li and Co salts was subsequently applied to this porous material followed by heating at 700 °C for 1 h to obtain LiCoO2 (LCO)-LLTO composite positive electrodes. These electrodes were subsequently assessed as components of all-solid-state Li secondary batteries (ASSBs). The effect of the amount of LCO loading on the electrochemical performance of these devices was evaluated, based on charge-discharge testing of ASSBs made by inserting Li3.25Ge0.25P0.75S4 between the LLTO and an In-Li alloy negative electrode. The porous LLTO permitted efficient utilization of the active material, and LCO loadings ranging from 1.1 to 6.5 mg cm−2 were possible, with a maximum capacity of 0.65 mAh cm−2. The electrochemical activity of 1 to 2 µm thick LCO layers prepared from molten salts on LLTO was confirmed in this work and LCO was demonstrated to function effectively as a component of a composite positive electrode. This synthesis using liquid sintering with molten salts is a promising approach to forming active electrochemical interfaces between oxides.