Electrolyte for lithium secondary battery comprising chelating agent and lithium secondary battery using the same

• US 7,745,056 B2
• Filed: 12/01/2006
• Issued: 06/29/2010
• Est. Priority Date: 12/02/2005
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Ok, Jong Hoa, Kil, Hyo Shik, Jung, Jong Mo, Lee, Sung Hyup, Ahn, Soon Ho, Kim, Jeong Min, Hong, Seung Tae, Lee, Jae Hyun
• Primary Examiner(s): Weiner; Laura S
• Application Number:
  US12/095,845
• Publication Number:
  US 20080280211A1
• Time in Patent Office: 1,306 Days
• Field of Search: 429/326, 429/200, 429/344, 429/307, 252/62.2
• US Class Current: 429/307
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

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

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.

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

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.

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