MULTILAYER SOLID-STATE ELECTROLYTE, BATTERY CELLS INCLUDING THE SAME, AND METHODS OF MAKING THE SAME

A multilayer solid-state electrolyte, solid-state battery cells including the same, and methods of making the electrolyte and the battery cells are disclosed. The multi-layer solid-state electrolyte includes a solid bulk electrolyte layer comprising carbon-doped lithium phosphorus oxynitride (LiPON) or WO(where 0≤x≤1), and a solid anode interface layer comprising LiPON or a metal oxide that forms a stable complex oxide with lithium oxide and conducts lithium ions when lithiated. The anode interface layer has a thickness less than that of the bulk electrolyte layer. The method of making the multi-layer solid-state electrolyte includes depositing one of the solid bulk electrolyte layer and the solid anode interface layer on an active layer of a battery cell, then depositing the other layer on the one layer. As for the solid-state electrolyte, the anode interface layer has a thickness less than that of the bulk electrolyte layer.