University of Minnesota

William H Smyrl

Boone B Owens

Stefano Passerini

Dinh Ba Le

Jun Xu

Amorphous manganese dioxide cathodes for lithium batteries with lithium metal or other lithium-containing anodes, the cathode being synthesized by a sol-gel approach involving reduction of sodium permanganate with fumaric acid disodium salt carried out at room temperature to ensure an amorphous structure. The resulting amorphous manganese dioxide has a nanoporous structure and a high internal surface area of 350 m /g. The amorphous manganese dioxide can electrochemically intercalate more than 1.6 moles of lithium per mole of manganese, and its theoretical capacity is 2 moles of lithium per mole of manganese. The host structure remains amorphous in the entire intercalation range and the intercalation process is reversible. Lithium battery cathodes comprising the amorphous manganese dioxide, a carbon powder and a binder provide a charge capacity in the level of 436 mAh/g and store energy at the level of 1056 mWh/g. Copper doped amorphous manganese oxides showed significant improvement in cycling performance.

Lithium batteries with new manganese oxide materials as lithium intercalation hosts

Nominal composition V.sub.2 O.sub.4.5 (OH) materials suitable for intercalations of greater than 2.4 Li per V.sub.2 O.sub.5 to yield theoretical energy density of greater than 970 Wh/Kg of cathode active material, the intercalation being completely reversible and synthesis of the materials from sol and gels, and devices incorporating these materials.

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New Brighton, MN, United States of America

William H Smyrl