Discovering a New class of fluoride solid-electrolyte materials via screening the structural property of Li-ion sublattice

New structures and compositions as inorganic solid-state electrolytes (ISSEs) are needed for all-solid-state lithium batteries (ASSLBs). Here we report the theoretical discovery of three new structure types by computational identification of nearest neighbor Li–Li distance (nRLi-Li) within Li-ion sublattice of fluorides which correlates with ISSEs ionic conductivity. This is achieved by computing Li-ions radial distribution functions and whose first peak corresponds to nRLi-Li. Subsequent theoretical exploration of the four fluorides with small nRLi-Li affords three materials (Li3MF6 (M = Al, Sc, Ga)) with crystal structures featuring three-dimensional diffusion channels for Li-ions. The three fluoride materials exhibit very well (electro)chemical stability and high ionic conductivity. The screening method used in this work will accelerate the systematic discovery of high ionic conductivity ISSEs for use in ASSLBs and related applications.