Theoretical picture of positive electrode–solid electrolyte interface in all-solid-state battery from electrochemistry and semiconductor physics viewpoints

All-solid-state battery has attracted significant attention as a promising next-generation energy storage. However, interfacial resistance of ion transport between the positive electrode and solid electrolyte is still a crucial issue for the all-solid-state battery commercialization. Although some mechanisms such as space charge layer and reaction layer effects have been suggested, the ionic and electronic behaviors at the solid–solid interfaces have not yet been fully elucidated. Here, we address theoretical microscopic understanding of the interfacial ionics and electronics from the viewpoints of electrochemistry and semiconductor physics, in conjunction with the results of recent density functional theory calculations.