Nonaqueous electrolytic solution and nonaqueous electrolyte secondary battery

Abstract

A nonaqueous electrolytic solution that can provide a high energy density nonaqueous electrolyte secondary battery having a high capacity, excellent storage characteristics, and excellent cycle characteristics and suppressing the decomposition of an electrolytic solution and the deterioration thereof when used in a high-temperature environment includes an electrolyte, a nonaqueous solvent, and a compound represented by general formula (1):

wherein R¹, R², and R³ each independently represent a hydrogen atom, a cyano group, or an optionally halogen atom-substituted hydrocarbon group having 1 to 10 carbon atoms, with the proviso that R¹ and R² do not simultaneously represent hydrogen atoms.

Description

TECHNICAL FIELD [0001]The present invention relates to nonaqueous electrolytic solutions and nonaqueous electrolyte secondary batteries. Specifically, the present invention relates to a specific component-containing nonaqueous electrolytic solution that can realize a secondary battery having improved battery characteristics, such as cycle characteristics and high-temperature storage characteristics, and relates to a nonaqueous electrolyte secondary battery including the nonaqueous electrolytic solution.BACKGROUND ART [0002]In recent years, there have been advances in the development of nonaqueous electrolyte secondary batteries with higher energy densities as progress toward a reduction in the size and weight of electric appliances. Furthermore, the expansion of fields of application of nonaqueous electrolyte secondary batteries require further improvement in battery characteristics.[0003]Hitherto, metallic lithium, metal compounds, such as elemental metals, oxides, and alloys of li...

AI Technical Summary

Benefits of technology

[0027]To overcome the foregoing problems relating to the graphite negative electrodes, it is another object of the present invention to provide a high energy density nonaqueous electrolyte secondary battery having a high capacity, excellent storage characteristics, and excellent cycle characteristics and suppressing the decomposition of an electrolytic solution used in the nonaqueous electrolyte secondary battery and the deterioration thereof when used in a high-temperature environment.

[0028]The inventors have conducted various studies and have found that the use of a nitrile compound having a specific structure minimizes the decomposition reaction of an electrolytic solution and, if an additive for forming a film on a negative electrode is added, also minimizes the decomposition reaction of the additive, thereby improving charge and discharge efficiency, storage characteristics, and cycle characteristics. The finding has led to the completion of the present invention.

Problems solved by technology

However, the performance, in particular, discharge capacity retention rates of the secondary batteries in charge-discharge cycles over longer periods of time, is still insufficient.

Furthermore, the conventional secondary batteries described above do not sufficiently overcome all problems of gas generation, the reduction in cycle characteristics, and the like when stored in a charged state at a high temperature.

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