Abstract: Solid composite electrolytes include (i) an amorphous matrix comprising one or more lithiophilic elements and (ii) lithium-based electrolyte crystals at least partially embedded in the amorphous matrix, the lithium-based electrolyte crystals having a different chemical composition than the amorphous matrix. After the composite is compressed or cycled in a battery, a surface portion of the composite has a concentration of the lithiophilic element(s) that is greater than an average concentration of the lithiophilic element(s) in a bulk portion of the composite.

Abstract: A method that includes contacting an amphipathic surface protective agent with a moisture sensitive Li-ion conductor material surface resulting in a protected Li-ion conductor material, and assembling an electrochemical cell that includes the protected Li-ion conductor material.