Nonaqueous electrolyte and nonaqueous-electrolyte battery

Abstract

A nonaqueous electrolyte includes an organic solvent and a lithium salt dissolved in the organic solvent, and a quaternary ammonium salt in an amount of 0.06 mol / L or greater and 0.5 mol / L or less, the quaternary ammonium salt having a structure represented by (chemical formula 3):wherein R is an organic linking group or an organic linking group forming an aromatic ring, the organic linking groups each having a main chain which has 4-5 atoms and is constituted of at least one member selected from carbon, oxygen, nitrogen, sulfur, and phosphorus and having one single-bond end and one double-bond end; R1 is an alkyl group having 1-6 carbon atoms or an alkyl group in which at least one of the hydrogen atoms has been replaced by a fluorine atom; and X− is a fluorine-containing anion.

Description

RELATED APPLICATIONS[0001]The present Application is a divisional Application of U.S. patent application Ser. No. 10 / 536,829 which was filed on May 27, 2005.TECHNICAL FIELD[0002]The present invention relates to a nonaqueous electrolyte and a nonaqueous-electrolyte battery. More particularly, the invention relates to an improvement in nonaqueous electrolytes.BACKGROUND ART[0003]Nonaqueous-electrolyte batteries, in particular, lithium secondary batteries, are recently attracting attention as power sources for portable appliances such as portable telephones, PHSs (simplified portable telephones), small computers, etc., power sources for power storage, and power sources for electric motorcars. In general, a lithium secondary battery is constituted of a positive electrode comprising a positive active material as a main component, a negative electrode comprising a negative-electrode material as a main component, and a nonaqueous electrolyte, and is produced by covering a power-generating ...

AI Technical Summary

Benefits of technology

The use of quaternary ammonium salts improves initial charge / discharge efficiency and high-rate discharge capabilities while maintaining battery safety by inhibiting organic solvent decomposition and forming a dense, lithium-ion permeable coating film.

Problems solved by technology

However, especially in the case of using a graphite in the negative electrode, there has been a problem that the organic solvent such as propylene carbonate decomposes on the graphite negative electrode and, hence, charge / discharge cannot be conducted at a high efficiency.

However, this technique was insufficient in the effect of inhibiting the decomposition of the organic solvent during first charge.

Furthermore, there has been a problem that vinylene carbonate has poor oxidation resistance and decomposes on the positive-electrode side and, hence, the addition of vinylene carbonate in a large amount reduces battery performances.

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