Danionics A/s

Valence Technology, Inc.

Keld West

Rene Koksbang

Girts Vitins

Birgit Zachau-Christiansen

The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li Co Mn O where 0<y<0.6. The lithium cobalt manganese oxide of the above formula can be the only active compound or can be used together with one or more other rechargeable compounds. The lithium cobalt manganese oxide of the above formula may be in air and moisture insensitive tetragonal form and provides additional active lithium to compensate for capacity losses in lithium ion cells and lithium-alloy cells.

Electrochemical cell

The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode, characterized in that the positive electrode structure thereof comprises (a) one or more materials selected from the group consisting of LiMn O , LiCoO , LiNiO , LiNi Co O where 0<x<1, preferably LiMn O and (b) one or more materials selected from the group consisting of orthorhombic LiMnO , monoclinic LiMnO (m-LiMnO ), hexagonal LiFeO (h-LiFeO ), &agr;-NaMnO , &bgr;-NaMnO , &agr;-NaFeO , and lithium/sodium compounds of the formula Li Na M(II)O , where x&gE;0, y&gE;0 and x&plus;y&lE;2, and where M(II) is a transition metal in oxidation state &plus;2, selected from the group consisting of Mn, Co, Ni and Fe, preferably Li Na Mn(II)O , where x&gE;0, y&gE;0 and x&plus;y&lE;2, more preferably LiNa MnO , the material(s) of group (a) being present in the electrode structure in an amount corresponding to 20-98% by weight of the complete electrode structure, and the material(s) of group (b) being present in the electrode structure in an amount corresponding to 1-79% by weight of the complete electrode stucture.

Rechargeable electrochemical cell of lithium ion or lithium alloy-type possessing metal oxide modified cathode structure with high first charge capacity

The present invention provides cathode active materials having as their major component or consisting essentially entirely of an oxide of vanadium of one of the nominal general formulas: Li.sub.a Fe.sub.x V.sub.y O.sub.z and Li.sub.m Fe.sub.x V.sub.y O.sub.z. In the case of Li.sub.a Fe.sub.x V.sub.y O.sub.z the material in an initial condition does not contain any lithium so a is equal to 0. In the case of Li.sub.m Fe.sub.x V.sub.y O.sub.z the material in an initial condition contains lithium so m is greater than 0. In both cases, x is about 1, y is about 3, and z is about 8. In both cases, the V(4) state is achieved by reaction between iron and V(5) in vanadium pentoxide. In one case lithium was added by including lithium hydroxide in an aqueous solution containing the iron and the vanadium pentoxide.

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Hellerup, Denmark

Keld West