Nonaqueous electrolyte secondary battery using lithium cobalt oxide as a positive active material and a nonaqueous electrolyte containing a sulfonyl-containing compound and vinylene carbonate
A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueous electrolyte solution, the battery being characterized in that the lithium cobalt oxide contains a group IVA element selected from the group consisting of Ti, Zr and Hf and a group IIA element of the periodic table, the nonaqueous electrolyte solution contains 0.2-1.5% by weight of a sulfonyl-containing compound and preferably further contains 0.5-4% by weight of vinylene carbonate.
1. A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueouselectrolyte solution, said battery being characterized in that said lithium cobalt oxide contains Zr and Mg and said nonaqueous electrolyte solution contains 0.2-1.5% by weight of divinyl sulfone and further contains vinylene carbonate.
2. The nonaqueous electrolyte secondary battery as recited in claim 1 , characterized in that the content of vinylene carbonate is 0.5-4% by weight.
3. The nonaqueous electrolyte secondary battery as recited in claim 1 , characterized in that the content of divinyl sulfone is 0.2-0.5% by weight.
4. The nonaqueous electrolyte secondary battery as recited in claim 1 , characterized in that the Zr content of the lithium cobalt oxide is 0.05-2.0 mole % and the Mg content of the lithium cobalt oxide is 0.1-2.0 mole %.