A theoretical approach to address interfacial problems in all-solid-state lithium ion batteries: tuning materials chemistry for electrolyte and buffer coatings based on Li6PA5Cl hali-chalcogenides

Abstract

Even though ultra-fast Li⁺ ion conductors based on sulfides such as LGPS and Li₆PS₅Cl have been developed in recent years, rather limited advancement has been made towards developing all-solid-state lithium ion batteries due to serious interface-related problems. Here in this work, we have carried out extensive fundamental modelling to formulate a system of materials based on hali-chalcogenide Li₆PA₅Cl argyrodites (A is the site for chalcogen species), so that materials with chemically and structurally compatible characteristics can be used as both a superb electrolyte and excellent buffer coatings over electrode surfaces. All solid-state-batteries (ASSBs) in the form of Li|Li₆PO₄SCl|Li₆PO₅Cl|Li_0.25MnO₂ are thus recommended, so that buffer coatings based on O-rich hali-chalcogenides help avoid interfacial reactions, owing to their high stability with respect to the cathodes and greatly enhanced chemical potential with respect to Li/Li⁺. Such batteries fundamentally have high mechanical and electrochemical stability, thus enabling high performance and great endurance to operational voltage.