1 Department of Chemistry, Technical University of Denmark2 University of Latvia3 Department of Chemical and Biochemical Engineering, Technical University of Denmark4 Danionics
The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0 <y <0.6. The lithium cobalt manganese oxide of the above formula can be the only active compound or can be used together with one or more other rechargeable compounds. The lithium cobalt manganese oxide of the above formula may be in air and moisture insensitive tetragonal form and provides additional active lithium to compensate for capacity losses in lithium ion cells and lithium-alloy cells.