Cation-substituted spinel oxide and oxyfluoride cathodes for lithium ion batteries

The present invention includes compositions and methods of making cation-substituted and fluorine-substituted spinel cathode compositions by firing a LiMn2−y−zLiyMzO4 oxide with NH4HF2 at low temperatures of between about 300 and 700° C. for 2 to 8 hours and a η of more than 0 and less than about 0.50, mixed two-phase compositions consisting of a spinel cathode and a layered oxide cathode, and coupling them with unmodified or surface modified graphite anodes in lithium ion cells.