# US 7,745,056 B2 · Electrolyte for lithium secondary battery comprising chelating agent and lithium secondary battery using the same

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- Number: US 7,745,056 B2
- Document ID: US7745056B2
- Status: Granted
- Kind: B2
- Application number: 12/095,845
- Filed: 2006-12-01
- Published: 2008-11-13
- Granted: 2010-06-29
- Earliest claimed: 2005-12-02
- Assignees: LG Chem, Ltd.
- Inventors: Jae Hyun Lee; Soon Ho Ahn; Jong Hoa Ok; Seung Tae Hong; Jeong Min Kim; Jong Mo Jung; Hyo Shik Kil; Sung Hyup Lee
- Web page: https://patentgrep.com/patent/US7745056B2

## CPC

- H01M 10/0567: characterised by the additives
- H01M 10/052: Li-accumulators
- H01M 10/4235: {Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence)}
- H01M 10/0565: Polymeric materials, e.g. gel-type or solid-type
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Disclosed herein is an electrolyte for lithium secondary batteries comprising: a chelating agent, which forms complexes with transition metal ions in the battery, and at the same time does not react and coordinate with lithium ions; a non-aqueous solvent; and an electrolyte salt, as well as a lithium secondary battery comprising the electrolyte. The chelating agent, which is contained in the electrolyte for lithium secondary batteries, can suppress a side reaction in which transition metal ions are reduced and deposited as transition metals on the anode. Also, the chelating agent can suppress internal short-circuits in the battery and the resulting voltage drop of the battery and a reduction in the safety and performance of the battery, which can occur when transition metals are deposited on the anode.

## Claims

### Claim 1

An electrolyte for lithium secondary batteries comprising: a chelating agent, which forms complexes with transition metal ions in the battery, and at the same time does not react and coordinate with lithium ions; a non-aqueous solvent; and an electrolyte salt,
wherein the chelating agent is at least one selected from the group consisting of NTA (nitrilotriacetic acid), DCTA (trans-1,2-diaminocyclohexanetetraacetic acid), DTPA (diethylene-triamine pentaacetic acid), and EGTA (ethylene glycol bis(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid),
wherein the chelating agent is contained in an amount of 2 to 200 mM relative to the electrolyte.

### Claim 2 (depends on 1)

The electrolyte of claim 1, wherein the complexes are insoluble in the electrolyte.

### Claim 3

A lithium secondary battery comprising an electrolyte for lithium secondary batteries, wherein the electrolyte comprises: a chelating agent, which forms complexes with transition metal ions in the battery, and at the same time does not react and coordinate with lithium ions; a non-aqueous solvent; and an electrolyte salt,
wherein the chelating agent is at least one selected from the group consisting of NTA (nitrilotriacetic acid), DCTA (trans-1,2-diaminocyclohexanetetraacetic acid), DTPA (diethylene-triamine pentaacetic acid), and EGTA (ethylene glycol bis(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid),
wherein the chelating agent is contained in an amount of 2 to 200 mM relative to the electrolyte.

### Claim 4 (depends on 3)

The lithium secondary battery of claim 3, wherein the complexes are insoluble in the electrolyte.