US Government As Represented by the Secretary of the Army

USA As Represented by Secretary of the Navy

Jeffrey B Wolfenstine

T Richard Jow

Jan L Allen

Joshua L Allen

Samuel A Delp, Iii

Wishvender K Behl

Donald L Foster

Jeffrey A Read

A positive electrode material having a nominal stoichiometry LiCoSiFeMM'(PO)where M is a trivalent cation selected from at least one of Cr, Ti, Al, Mn, Ni, V, Sc, La and/or Ga, M&#x2032; is a divalent cation selected from at least one of Mn, Ni, Zn, Sr, Cu, Ca and/or Mg, y is within a range of 0&#x3c;y&#x2264;0.10 and x is within a range of 0&#x2264;x&#x2264;0.2. The use of double compositional modification to LiCoPOincreases the discharge capacity from &#x2dc;100 mAh/g to about 130 mAh/g while retaining the discharge capacity retention of the singly Fe-substituted LiCoPO. Additional compositional modification to include Si increases the cycle life and greatly improved the coulombic efficiency to between 97-100% at a C/3 cycle rate.

High voltage lithium ion positive electrode material

A positive electrode material having a nominal stoichiometry LiCoSiFeMM'(PO)where M is a trivalent cation selected from at least one of Cr, Ti, Al, Mn, Ni, V, Sc, La and/or Ga, M&#x2032; is a divalent cation selected from at least one of Mn, Ni, Zn, Sr, Cu, Ca and/or Mg, y is within a range of 0&#x3c;y&#x2266;0.10 and x is within a range of 0&#x2266;x&#x2266;0.2. The use of double compositional modification to LiCoPOincreases the discharge capacity from &#x2dc;100 mAh/g to about 130 mAh/g while retaining the discharge capacity retention of the singly Fe-substituted LiCoPO. Additional compositional modification to include Si increases the cycle life and greatly improved the coulombic efficiency to between 97-100% at a C/3 cycle rate.

A lithiated metal phosphate material substituted by divalent atoms at the M2 site and trivalent atoms, a portion of which are present at both the M2 and the M1 sites. The substituted material has the general formula of LiMTDPO, wherein M is selected from the group consisting of Mn, Co, Niand combinations thereof; T is selected from the group consisting of Fe, Aland Gaand a portion of said T resides at the M2 sites, said portion being greater than 0 and no more than 99 percent of the total T atoms; D is selected from the group consisting of Fe, Mn, Co, Ni, Mg, Zn, Caand combinations thereof; d has a value greater than 0 and no more than 0.3; and t has a value in the range of 0 to 0.3. Also disclosed are electrodes which incorporate the substituted metal phosphate material and are disposed in electrochemical cells as well as batteries, including rechargeable lithium ion batteries. Finally, there is disclosed a method of increasing the life cycle of an electrode by forming the electrode by mixing and dissolving LiHPO, Co(OH)and FeCO.2HO in HNO, evaporating the water from this solution to form a solid powder mixture, heating said mixture to around 600&#xb0; C. under Nfor approximately 12 hours, cooling, ball milling for about 30 minutes the mixture with 0.01-10 wt. % acetylene black; heating the mixture again to around 600&#xb0; C. under Nfor about an hour and then coating the mixture onto an Al foil substrate to produce a composite electrode.

High voltage lithium ion positive electrode material with improved cycle life

An electrode for a rechargeable lithium-ion battery is formed by mixing stanous oxide (SnO) and lithium nitride (Li,N) in a stoichiometric ratio of 2 moles of Li,N to 3 moles of SnO to form a mixture, milling the mixture to obtain a milled powder, and processing the milled powder in accordance with an electrode-forming technique. The electrode forming technique can be any one of die pressing, spraying, doctor-blading and rolling. Conductive additives, such as carbon and binders (PVDF, cellulose and Teflon), can be introduced during the processing step. Preferably, the method is carried out in a dry, inert atmosphere of argon or helium. As a result of the invention, a smaller, lighter and more efficient lithium-ion battery is produced.

Electrode for rechargeable lithium-ion battery and method of fabrication

A lithium ion secondary electrochemical cell includes an anode comprising both a material capable of reversibly incorporating an alkali metal, and a copper current collector, a cathode capable of reversibly incorporating an alkali metal, and an electrolyte which includes a solution of an alkali metal salt dissolved in a polar organic solvent. A method of preventing the electrochemical dissolution of the copper current collector in the lithium ion battery electrolyte includes charging the lithium ion cell immediately after its assembly. By immediately charging the freshly assembled lithium ion cell, lithium will be intercalated into carbon. The copper current collector, therefore, will be at the lithium-carbon potential and thus will be cathodically protected, and will not electrochemically dissolve in the lithium ion battery electrolyte.

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Silver Spring, MD, United States of America

Jeffrey B Wolfenstine