The present disclosure relates to novel compositions, electrodes, electrochemical storage devices (batteries) and ionic conduction devices that use cubic ionic conductor ("CUBICON") compounds, such as nitridophosphate compounds. The cubic ionic conductor compound have a framework formula [MT.sub.3X.sub.10].sup.n- (1) and a general formula A.sub.xMT.sub.3X.sub.10 (2), where M is a cation in octahedral coordination, T is a cation in tetrahedral coordination, X is an anion, and the framework has a net negative charge of -n, a net charge of +n. The framework of this class of compounds can accept excess ions.
STATEMENT OF GOVERNMENT LICENSE RIGHTS
 The present invention was made with government support under contract number DE-AC02-98CH10886 awarded by the U.S. Department of Energy. The United States government has certain rights in the invention.