Mechanochemical synthesis of Li<sub>2</sub>O–LiI-based solid electrolytes with glass-forming oxides

Oxide-based lithium-ion conductive solid electrolytes are promising owing to their safety. Both crystalline and glass-oxide solid electrolytes have been explored to obtain materials with high ionic conductivity and ductility. Amorphous Li2O–LiI solid electrolytes exhibit ionic conductivities of approximately 10−5 S cm−1 and excellent ductility, and all-solid-state batteries can be fabricated solely by cold pressing. However, the ionic conductivity of Li2O–LiI solid electrolytes should be further increased to enhance battery performance. Herein, glass-forming oxides (B2O3, SiO2, P2O5, and GeO2) and intermediate oxides (Al2O3 and V2O3) were added to Li2O–LiI solid electrolytes using mechanochemical techniques to increase the ionic conductivity of Li2O–LiI solid electrolytes. The structure varied depending on the additives used in the prepared Li2O–LiI-based solid electrolytes. The ionic conductivity decreased as the amount added increased. However, the ionic conductivity was maintained after V2O3 was added. V2O3 is preferable candidates for increasing the ionic conductivity of Li2O–LiI solid electrolytes. Our fundamental research on material synthesis will contribute to the future development of oxide-based solid-electrolyte materials.