Charge-discharge-induced local strain distributions in a lithium amide-borohydride-iodide [LiBH4-LiNH2-LiI] solid electrolyte

Abstract All-solid-state batteries based on solid-state electrolytes (SSE) have attracted considerable attention due to their high capacity and relative safety, compared to conventional batteries based on liquid electrolytes. As ions migrate from the electrodes through solid electrolytes (during charge and discharge cycles of an all-solid-state battery), they exert strains of varying proportions that are distributed across the electrolytes. Here, we show that, for an all-solid-state lithium-oxygen battery based on the SSE lithium amide-borohydride-iodide (LiBH4-LiNH2-LiI), the heterogeneous nature of the electrolyte leads to spatial and temporal variations in the induced strain distributions. The strains associated with discharging are much greater than those induced during charging. These results suggest that charging and discharging processes lead to local strain build-up and possible failure of solid electrolytes. The implications of the results are also discussed for the development of robust-solid-state batteries.