| abstract |
A positive electrode is disclosed for a non-aqueous electrolyte lithium rechargeable cell or battery. The electrode comprises a lithium containing material of the formula Na y Li x Ni z Mn 1-z-z′ M z′ O d , wherein M is a metal cation, x+y>1, 0<z<0.5, 0≤z′<0.5, y+x+1 is less than d, and the value of d depends on the proportions and average oxidation states of the metallic elements, Li, Na, Mn, Ni, and M, if present, such that the combined positive charge of the metallic elements is balanced by the number of oxygen anions, d. The inventive material preferably has a spinel or spinel-like component in its structure. The value of y preferably is less than about 0.2, and M comprises one or more metal cations selected preferably from one or more monovalent, divalent, trivalent or tetravalent cations, such as Mg 2+ , Co 2+ , Co 3+ , B 3+ , Ga 3+ , Fe 2+ , Fe 3+ , Al 3+ , and Ti 4+ . The electrode material can be synthesized using an ion-exchange reaction with a lithium salt in an organic-based solvent to partially replace sodium ions of a precursor material with lithium ions. |