David Chiyu Shen

45500649, Oct 29, 1985

Dec 8, 1983

6/559345

Shiao-Ping S. Yen - Altadena CA
Boyd J. Carter - S. San Gabriel CA
David H. Shen - Rosemead CA
Robert B. Somoano - LaCanada CA

California Institute of Technology - Pasadena CA

H01M 400

429 94

A secondary battery (10) of high energy density and long cycle is achieved by coating the separator (18) with a film (21) of cationic polymer such as polyvinyl-imidazoline. The binder of the positive electrode (14) such as an ethylene-propylene elastomer binder (26) containing particles (28) of TiS. sub. 2 chalcogenide can also be modified to contain sulfone functional groups by incorporating liquid or solid sulfone materials such as 0. 1 to 5 percent by weight of sulfolane into the binder. The negative lithium electrode (14), separator (18) and positive electrode (16) are preferably spirally wound and disposed within a sealed casing (17) containing terminals (32, 34). The modified separator and positive electrode are more wettable by the electrolytes in which a salt is dissolved in a polar solvent such as sulfolane.

54278724, Jun 27, 1995

Nov 17, 1993

8/154322

David H. Shen - Arcadia CA
Subbarao Surampudi - Glendora CA
Chen-Kuo Huang - South Pasadena CA
Gerald Halpert - Pasadena CA

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

H01M 214

429142

Dendrites are prevented from shorting a secondary lithium battery by use of a first porous separator such as porous polypropylene adjacent the lithium anode that is unreactive with lithium and a second porous fluoropolymer separator between the cathode and the first separator such as polytetrafluoroethylene that is reactive with lithium. As the tip of a lithium dendrite contacts the second separator, an exothermic reaction occurs locally between the lithium dendrite and the fluoropolymer separator. This results in the prevention of the dendrite propagation to the cathode.

50305280, Jul 9, 1991

May 7, 1990

7/520265

David H. Shen - Arcadia CA
Subbarao Surampudi - Glendora CA
Fotios Deligiannis - San Gabriel CA
Gerald Halpert - Pasadena CA

The California Institute of Technology - Pasadena CA

H01M 616

429197

The present invention comprises an improved electrolyte for secondary lithium-based cells as well as batteries fabricated using this electrolyte. The electrolyte is a lithium containing salt dissolved in a non-aqueous solvent, which is made from a mixture of ethylene carbonate, ethylene propylene diene terpolymer, 2-methylfuran, and 2-methyltetrahydrofuran. This improved, mixed solvent electrolyte is more conductive than prior electrolytes and much less corrosive to lithium anodes. Batteries constructed with this improved electrolyte utilize lithium or lithium alloy anodes and cathodes made of metal chalcogenides or oxides, such as TiS. sub. 2, NbSe. sub. 3, V. sub. 6 O. sub. 13, V. sub. 2 O. sub. 5, MoS. sub. 2, MoS. sub. 3, CoO. sub. 2, or CrO. sub. 2, dissolved in a supporting polymer matrix, like EPDM. The preferred non-aqueous solvent mixture comprises approximately 5 to 30 volume percent ethylene carbonate, approximately 0. 01 to 0.