The present invention relates to novel compositions, electrodes, electrochemical storage devices (batteries) and ionic conduction devices that use cubic ionic conductor ("CUBICON") compounds, preferably 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, where a variable number of potentially mobile additional chemical species, A, can fit into the open space within this framework with a net charge of +n.
STATEMENT OF GOVERNMENT LICENSE RIGHTS
 The present invention was made with government support under award number DE-SC0001294 made to the Northeastern Center for Chemical Energy Storage under EFRC program awarded by the U.S. Department of Energy and under contract number DE-AC02-98CH10886 also awarded by the U.S. Department of Energy. The United States government has certain rights in the invention.