In some embodiments, a solid electrolyte comprises or exhibits a structure, such as a crystal structure, including voids or defects, such as crystallographic defects, that permit conduction or migration of ions through the solid electrolyte at temperatures between about 0° C. and about 100° C. It will be appreciated that operation at temperatures between about 0° C. and about 50° C. is especially desirable, but the electrolytes may permit operation at temperatures above these temperatures, including above 100° C. In some embodiments, the solid electrolyte comprises or exhibits a structure including voids or defects that also permit conduction or migration of ions through the solid electrolyte at temperatures outside of the previously mentioned range, such as at temperatures less than about 0° C. or greater than about 100° C. As described above, it will be appreciated that this property may be contrasted with the same material of the solid electrolyte in the bulk, where voids and defects that are present in the bulk material may still not provide for suitable ionic conductivity, since the overall thickness of the material in bulk may provide an effect that reduces ionic conductivity. Optionally, the defects correspond to one or more vacancy defects, interstitial defects, boundary defects, line defects, planar defects, bulk defects, or lattice imperfections.