2D van der Waals Inorganic Oxychloride Proton Conductor

Inorganic solid ion conductors are attractive candidates as electrolytes for next-generation lithium-ion batteries (LIBs) and fuel cells (FCs), which are expected to operate at high voltage and temperature because of their high stability and oxidation resistance. However, in previously developed inorganic ion conductors derived from natural minerals, mobile ions are strongly bonded to anions, resulting in low conductivity. Thus, in this study, we present a two-dimensional (2D) van der Waals (vdW) inorganic proton (H + ) conductor for inserting protons into halogen vdW layers. In the best case, conductivity is ∼10 mS cm –1  at 120 °C, which is 2 orders of magnitude larger than that of inorganic conductors previously developed from natural minerals. The design of ion conductors using 2D-vdW inorganic materials can provide a route for high-performance LIBs and FCs.