Li3CaB2O5F: a unique sandwich-like structure with diverse and wide Li ion diffusion pathways

A new borate fluoride, Li3CaB2O5F, has been synthesized. It features a sandwich-like structure with the adjacent [Li3OF]∞ and [CaO]∞ layers connected by the weak Li-O bonds and the [B2O5] dimers. Interestingly, Li3CaB2O5F has large ionic conductivity, which is attributed to the diverse and wide Li-ion diffusion pathways.