Lithium batteries and method of preparing a positive electrode material therefor

Claim 2

A galvanic cell according to claim 2 wherein said product is obtained by heating Ni3S2 in the presence of air.

Claim 3

A galvanic cell according to claim 1 wherein said cathode comprises a mixture of said product and a conductive binder.

Claim 4

A galvanic cell according to claim 4 wherein said cathode comprises said mixture on a conductive substrate.

Claim 5

Method of preparing a positive plate material for use in a galvanic cell having a negative electrode that comprises lithium, said method comprising heating Ni3S2 in the presence of an oxidant at a temperature of between about 300*C and about 350*C for a period of at least ten minutes so as to produce a reaction product that has a discharge potential that is greater than untreated Ni3S2 with respect to Li/Li and has a greater coulombic capacity than untreated Ni3S2.

Claim 6

Method of claim 6 wherein said oxidant is oxygen.

Claim 7

Method of claim 6 wherein said oxidant is air.

Claim 8

Method of treating Ni3S2 for use as positive electrode material in a lithium battery comprising heating Ni3S2 in the presence of molecular oxygen at a temperature of between about 300*C and about 350*C for a period of time sufficient to produce an oxidation product that as compared to untreated Ni3S2 has a greater coulombic discharge capacity and has a greater discharge potential with respect to Li/Li .

Claim 9

Method of preparing a positive electrode material for use in a galvanic cell in which the negative electrode material comprises lithium, said method comprising the steps of subjecting anhydrous NiSO4 to heating at a temperature between about 300*C and about 350*C in the presence of hydrogen for a period of time sufficient to convert substantially all of said NiSO4 to Ni3S2, cooling said Ni3S2 in the presence of an inert gas so that said Ni3S2 is rendered resistant to combustive oxidation when exposed to air, and thereafter heating said Ni3S2 in the presence of an oxidant at a temperature of between about 300*C and about 350*C and for at least ten minutes so that its coulombic capacity and its discharge potential when ionically coupled to lithium by a non-aqueous electrolyte is greater than that of untreated Ni3S2.

Claim 10

Method of claim 10 wherein said oxidant is molecular oxygen.

Claim 11

In the method of manufacturing a galvanic cell by (a) providing a negative plate comprising lithium, (b) providing a positive plate material formed from Ni3S2, (c) providing a non-aqueous electrolyte comprising an ionizeable salt in an aprotic organic solvent, and (d) contacting said negative plate and said positive plate material with said electrolyte, the improvement comprising subjecting said Ni3S2 before said positive plate material is contacted with said electrolyte to heating in the presence of molecular oxygen at a temperature of between about 300*C and about 350*C for at least 10-15 minutes so as to increase the coulombic capacity and also the discharge potential of said Ni3S2 in said cell.

Claim 12

The invention of claim 12 wherein said positive plate material is a mixture that includes a binder, and further wherein the step of subjecting said Ni3S2 to heating in the presence of oxygen is conducted in the presence of said binder.

Claim 13

The invention of claim 12 wherein said positive plate material is a mixture that includes a binder, and further wherein the step of subjecting said Ni3S2 to heating in the presence of oxygen is conducted in the absence of said binder.