Control of the interfacial chemistry of the electrodes in lithium batteries is vitally important to their safe and effective application. Water and virtually every organic solvent is thermodynamically unstable in the presence of metallic lithium. The electrode potential of a graphite electrode in a lithium-ion battery at the top of charge is at an equivalent chemical potential. In principle, the entire lithium or charged graphite electrode can be completely consumed by reaction with the solvent if the interfacial chemistry is not adventitious, i.e. does not form a reaction self-limiting passive film. A greater understanding of the reactions of the electrolyte and the nature of passivity will be essential to utilize metallic lithium or hosts like silicon that store equivalent amounts of lithium. A surface science approach, like that presented here but now out of fashion, may provide additional insight to approaches currently being used.