Mechanochemical synthesis of Li₂O–LiI-based solid electrolytes with glass-forming oxides

Abstract

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.