Sodium and Lithium Intercalation Within The Layered Oxides Na(Li)xMo2O4

The structural, chemical and electrochemical behavior of the layered molybdate oxides Na(Li)xMo2O4 have been investigated. We found a reversible sodium intercalation process over the range of composition 0.5 < x < 1.9 for the NaxMo2O4 system with 5 single phase domains at x = 0.55, 0.9, 1-1.4, 1.6, and 1.9. We took advantage of the high mobility of sodium diffusion in this compound to exchange sodium for lithium at relatively low temperature (300°C) and to prepare crystallographically pure LixMo2O4. Electrochemical data for the Li system shows that this material, which reversibly intercalates up to 1.7 Li atoms at an average potential of 3.1 volts, is a new promising cathode material for secondary lithium batteries. The ease with which these new molybdate phases can be intercalated is not limited to the alkali metals, since we also were able to intercalate H2O molecules.