Mark A Capparella

US Patent:

58636757, Jan 26, 1999

Filed:

Jun 24, 1997

Appl. No.:

8/881453

Inventors:

Mark Capparella - Milford MA
William L. Bowden - Nashua NH
Radek Fooksa - Needham MA

Assignee:

Duracell, Inc - Bethel CT

International Classification:

H01M 450

US Classification:

429224

Abstract:

Disclosed is a process for treating manganese dioxide containing ion-exchangeable cations by replacing the ion-exchangeable cations present in the manganese dioxide with lithium by a process comprising first replacing ion-exchangeable cations present in the manganese dioxide with hydrogen. This readily is accomplished by slurrying the manganese dioxide in an aqueous acid solution. The resulting acidic manganese dioxide then is neutralized with a basic solution of a lithium containing compound, such as lithium hydroxide. This neutralization step serves to accomplish replacement of the previously introduced hydrogen, by ion-exchange, with lithium. The manganese dioxide then is washed with water, dried, and heat-treated at an elevated temperature, in conventional manner, to convert the gamma manganese dioxide to a mixture of the gamma and beta forms, which then is used as the active cathodic component in an electrochemical cell.

US Patent:

56981767, Dec 16, 1997

Filed:

Jun 7, 1995

Appl. No.:

8/474871

Inventors:

Mark Capparella - Milford MA
William L. Bowden - Nashua NH
Radek Fooksa - Needham MA

Assignee:

Duracell, Inc. - Bethel CT

International Classification:

C01G 4502

US Classification:

423605

Abstract:

Disclosed is a process for treating manganese dioxide containing ion-exchangeable cations by replacing the ion-exchangeable cations present in the manganese dioxide with lithium by a process comprising first replacing ion-exchangeable cations present in the manganese dioxide with hydrogen. This readily is accomplished by slurrying the manganese dioxide in an aqueous acid solution. The resulting acidic manganese dioxide then is neutralized with a basic solution of a lithium containing compound, such as lithium hydroxide. This neutralization step serves to accomplish replacement of the previously introduced hydrogen, by ion-exchange, with lithium. The manganese dioxide then is washed with water, dried, and heat-treated at an elevated temperature, in conventional manner, to convert the gamma manganese dioxide to a mixture of the gamma and beta forms, which then is used as the active cathodic component in an electrochemical cell.