Nonaqueous electrolyte solution, method for producing same, and nonaqueous electrolyte battery using the electrolyte solution

Abstract

To provide: a novel nonaqueous electrolyte solution which uses a methylene bissulfonate derivative, reduces the initial irreversible capacity of a battery, and improves battery characteristics such as cycle characteristics, electric capacity and storage characteristics,a method for producing the nonaqueous electrolyte solution,and a battery which uses the electrolyte solution. [Solution] The present invention relates to the following <1>-<3>. <1> A nonaqueous electrolyte solution which contains the following (1)-(3). (1) A nonaqueous solvent which contains at least one ester selected from among cyclic carbonate esters, chain carbonate esters and cyclic carboxylic acid esters. (2) A lithium salt which can be dissolved as an electrolyte salt into the nonaqueous solvent. (3) A methylene bissulfonate derivative which is represented by general formula [I]. <2> A method for producing a nonaqueous electrolyte solution, which is characterized in that a lithium salt is dissolved in a nonaqueous solvent and then the methylene bissulfonate derivative is dissolved in the nonaqueous solvent. <3> A nonaqueous electrolyte battery which comprises (i) the nonaqueous electrolyte solution set forth in <1>, (ii) a negative electrode, (iii) a positive electrode and (iv) a separator.

Description

technical field [0001] The invention relates to a new type of non-aqueous electrolyte, its manufacturing method and a non-aqueous electrolyte battery using the electrolyte. The non-aqueous electrolyte uses methylene bissulfonate derivatives, which can reduce the initial irreversible capacity of the battery , which in turn can improve battery characteristics such as cycle characteristics, capacity, and storage characteristics. Background technique [0002] In recent years, with the spread of various small portable electronic devices such as portable electronic terminals such as mobile phones and notebook computers, secondary batteries have played an important role as their power sources. [0003] Lithium secondary batteries are widely used as power sources for electronic devices such as mobile phones and notebook personal computers, power sources for electric vehicles, and power storage, etc., and are mainly composed of a positive electrode, a non-aqueous electrolyte, and a n...

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Problems solved by technology

[0022] However, for example, the above-mentioned disulfonic acid ester derivatives, sulfonic acid ester derivatives, fluorine-containing sulfonic acid ester compounds, etc. are not sufficiently capable of forming a coating on the negative electrode, and there is a problem that it is impossible to form a coating that sufficiently inhibits the reductive decomposition of the non-aqueous electrolyte solution. film, and the durability of the film is not sufficient

As a result, there are problems such as an increase in the initial irreversible capacity and a decrease in the charge-discharge efficiency in the first cycle.

Even if an excessive amount of disulfonic acid ester derivatives is added to the non-aqueous electrolyte solution to improve this problem, the resistance of the coating component formed on the surface of the negative electrode will increase, which will lead to the problem of lower battery performance.

Therefore, adding these additives to the electrolyte is insufficient to improve the overall balance of the battery characteristics and the cost of the non-aqueous electrolyte, environmental protection, manufacturing process, etc.

[0023] In addition, when preparing a non-aqueous electrolyte, the temperature of the non-aqueous electrolyte itself will rise due to the heat generation of the above-mentioned lithium salt during dissolution and preparation, and the lithium salt in the non-aqueous electrolyte will react with the moisture in the system and decompose. Problems with the formation of free acids such as hydrogen fluoride (HF)

Especially when preparing non-aqueous electrolytes containing the above-mentioned sultone compounds or disulfonate derivatives, etc., the above-mentioned side reactions are promoted due to the temperature rise during preparation, or the sultone compounds, disulfonate derivatives, etc. substances, fluorine-containing sulfonate compound self-decomposition, etc. As a result, there are problems such as high free acid in the non-aqueous electrolyte solution, so it is necessary to prevent the temperature of the non-aqueous electrolyte solution from rising and prevent the deterioration of the non-aqueous electrolyte solution.

[0024] From the above, in the prior art, the non-aqueous electrolytic solution that can satisfy the related problems of the above-mentioned lithium salt and the related problems of the non-aqueous solvent is still under study, and it is necessary to further improve the optimal combination and the combination of new additives. Use and its formulation, etc., make it difficult to show the various negative effects of the constituent elements of the non-aqueous electrolyte (non-aqueous solvent, lithium salt, additives, etc.)

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