| 摘要 |
PROBLEM TO BE SOLVED: To improve the charge and discharge cycle characteristic and the storage characteristic in the charge condition by including gamma sultone compound in the nonaqueous electrolyte provided in a battery with a negative electrode and a positive electrode mainly composed of a material capable of storing and discharging lithium or the lithium metal. SOLUTION: The gamma sultone compound expressed with a formula and included at 0.01-3.0 mole/l of content forms a stable film of quality in a surface of a negative electrode. This film cuts a contact of the negative electrode with the solvent molecule so as to restrict the lowering of the discharge capacity in the charge and discharge cycle, and smoothens the transference of charge from the negative electrode and the diffusion of the lithium ion in the electrolyte, and prevents the gradation of the nonaqueous electrolyte. As an electrolyte salt, one or more kinds of LiPF6, LiBF4 and LiN(C2F5SO2)2 is desirably used, and the battery performance is improved more. As the positive electrode active material, lithium compound oxide including one or more kinds of transition metal is used. In the formula, R1-R6 separately means hydrogen alkyl group having 1-6 carbon and fluorine atom substituent alkyl group having 1-6 carbon. |
