A 2D Layered Natural Ore as a Novel Solid-State Electrolyte

Two-dimensional (2D) layered materials have showed their superiority in ionic transport, not only as electrode materials but also as solid-state electrolytes in lithium-ion batteries (LIBs). Silicates are one kind of natural ore with 2D layered structures which have been reported as additives in composite polymeric electrolytes (CPEs) for inhibiting the crystallization of the polymer electrolyte (e.g., poly(ethylene oxide) (PEO)), facilitating the dissociation of Li+ and thereby enhancing the ionic conductivity. However, the possibility of silicates as electrolytes has not been investigated. In this paper, we report that 2D natural ore can be used as SSEs by using lepidolite as a proof-of-concept. Both pure lepidolite and composite lepidolite (only mixed with PEO) showed moderate ionic conductivity, proving the intrinsic ionic conductibility of lepidolite. The ionic conductivity originating from lepidolite can also be confirmed by the larger Li+ transference number when higher a content of lepidolite is adopted in the composites. These results will enrich the materials for SSEs and arouse growing interest of 2D layered silicates for potential application of all-solid-state lithium-ion batteries and lithium–metal batteries.