We now consider the chemical compatibility of oxide anolytes with the chloride catholytes listed in Table . We include Li 2 O in our list of oxides as it is a common decomposition product of many oxide SEs (e.g., LLZO, and LiPON) when placed in contact with Li metal. We now analyze the reactivity of LLZO with different chlorides, as LLZO is the most widely studied oxide SE. Our results suggest that LLZO is highly reactive with all of the chloride catholytes studied here, and LiCl consistently forms as a major decomposition product.