Battery

Abstract

A battery capable of improving battery characteristics such as cycle characteristics and high temperature storage characteristics is provided. An anode includes an anode active material which includes Sn or Si as an element. A separator is impregnated with an electrolyte solution, and the electrolyte solution includes an acid anhydride such as succinic anhydride or a derivative thereof. Thereby, a coating is formed on the anode, and the decomposition of the electrolyte solution in the anode can be prevented. An electrolyte solution to which 4-fluoro-1,3-dioxolane-2-one is mixed is more preferably used.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]The present application is a Continuation off of U.S. application Ser. No. 11 / 267,641 filed on Nov. 3, 2005, which claims priority to Japanese Patent Application No. JP 2004-322740 filed on Nov. 5, 2004 and Japanese Patent Application No. JP 2005-121214 filed on Apr. 19, 2005, the entire contents of which are being incorporated herein by reference.BACKGROUND[0002]The present invention relates to a battery using an anode active material which includes at least one of tin (Sn) and silicon (Si) as an element.[0003]The development of batteries with a higher energy density has been demanded according to the downsizing of electronic devices. As a battery which meets the demand, a lithium metal secondary battery using precipitation-dissolution reactions of lithium (Li) is cited. However, in the lithium metal secondary battery, during charge, lithium (Li) is deposited on an anode to form a dendrite, thereby lithium is inactivated, so there is an...

AI Technical Summary

Benefits of technology

[0012]In the battery according to the embodiment of the invention, the electrolyte solution includes at least one kind of additive selected from the group consisting of acid anhydrides and derivatives of the acid anhydrides, so a coating on the basis of the additive is formed on the anode during charge and discharge, thereby the decomposition of the electrolyte solution can be prevented. Therefore, even if an anode active material including at least one of tin and silicon as an element is used, battery characteristics such as cycle characteristics and high temperature storage characteristics can be improved.

[0013]In particular, when the content of the additive in the electrolyte solution is within a range from 0.001 wt % to 10 wt % inclusive, or when the electrolyte solution includes a derivative of a cyclic carbonate having a halogen atom, higher effects could be obtained.

Problems solved by technology

However, in the lithium metal secondary battery, during charge, lithium (Li) is deposited on an anode to form a dendrite, thereby lithium is inactivated, so there is an issue that the cycle life of the lithium metal secondary battery is short.

However, an anode capacity by intercalation has an upper limit stipulated by the composition C6Li of a first stage graphite intercalation compound.

Moreover, it is industrially difficult to control a minute pore structure of the carbonaceous material, and by controlling the minute pore structure, the specific gravity of the carbonaceous material declines, so using the carbonaceous material is not an effective means of improving the anode capacity per unit volume and by extension to a battery capacity per unit volume.

It is known that some low-temperature fired carbonaceous materials exhibit an anode discharge capacity exceeding 1000 mAh / g; however, there is an issue that when the battery includes a metal oxide or the like as a cathode, discharge voltage declines, because the metal oxide has a large capacity at a noble potential of 0.8 V or more relative to lithium metal.

Because of these issues, it is considered that it is difficult for existing carbonaceous materials to meet demands for a longer operating time of electronic devices in future and a higher energy density of power sources.

However, when these alloys are used for an anode of a battery, cycle characteristics will decline.

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