Non-aqueous electrolyte battery

Abstract

A non-aqueous electrolyte battery with improved cyclic characteristics and battery capacity at high temperature and capable of suppressing the evolution of gas during storage at high temperature while maintaining favorable cyclic performance, wherein vinylene carbonate (VC) and alpha-angelica lactone (4-hydroxy-3-pentenic acid gamma-lactone) are contained in the electrolyte, and whereby a highly soft and flexible coating film with alpha-angelica lactone is formed on the surface of the negative electrode without reducing the initial charging efficiency of the battery. Since a mixed coating film comprising VC and alpha-angelica lactone is formed on the soft and flexible coating film and the mixed coating film has higher thermal stability at high temperature than that of the coating film formed only with VC, the cyclic characteristics of the battery at high temperature can be improved while enhancing the suppression of gas evolution during storage at high temperature.

Description

technical field [0001] The present invention relates to a negative electrode capable of reversibly inserting and detaching lithium, a positive electrode capable of reversibly inserting and detaching lithium at a noble potential, a separator separating these positive electrodes and negative electrodes, and a lithium salt formed by dissolving in an organic solvent A non-aqueous electrolyte battery composed of a solute electrolyte. Background technique [0002] In recent years, non-aqueous electrolyte batteries represented by lithium secondary batteries have been put into practical use as small, lightweight and high-capacity batteries, and are used in portable electronic devices such as small cameras, mobile phones, and notebook computers. In the power supply of communication equipment, etc. Such a lithium secondary battery is a battery configured as follows, that is, a material capable of intercalating and detaching lithium ions is used as the negative electrode active materi...

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Problems solved by technology

[0013] In addition, as shown in the above-mentioned patent document 2, when only α-angelica lactone is added to the electrolyte, since the covering film (SEI) formed on the surface of the carbon negative electrode is very weak, it is difficult to sufficiently suppress the carbon negative electrode. side reactions associated with organic solvents

This causes a problem that the cycle characteristics are not sufficiently improved.

[0014] In addition, as shown in the above-mentioned patent document 3, when using a non-aqueous electrolytic solution in which a cyclic carbonate having a carbon-carbon unsaturated bond such as VC is added to a cyclic carboxylate, it is possible to obtain Lithium secondary battery with excellent charge and discharge characteristics, but when a large amount of cyclic carboxylate or VC is used, the capacity will decrease due to reduction and decomposition, and the negative electrode surface coating film with hardness and thickness more than required will be formed ( Problems such as degradation of battery characteristics due to SEI) and gas generation due to SEI decomposition during high-temperature storage

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