Organic electrolyte and lithium secondary battery

• US 6,503,663 B1
• Filed: 05/05/2000
• Issued: 01/07/2003
• Est. Priority Date: 05/05/2000
• Status: Expired due to Term

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Jung, Won-il, Hwang, Duck-chul, Song, Eui-hwan
• Primary Examiner(s): WEINER, LAURA S
• Application Number:
  US09/565,069
• Time in Patent Office: 977 Days
• Field of Search: 429/330, 429/332, 429/322, 429/231.1, 429/231.8, 429/231.95, 429/331, 429/323
• US Class Current: 429/331
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/004 Three solvents
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An organic electrolyte containing an organic solvent mixture and a lithium salt, wherein the organic solvent mixture includes 20 to 60% by volume of ethylene carbonate, 5 to 30% by volume of polypropylene carbonate, and 20 to 70% by volume of chain carbonate. The organic electrolyte improves charge/discharge cycle characteristics while maintaining high discharge capacity and low-temperature discharge characteristics.

Claims

1. An organic electrolyte containing an organic solvent mixture and a lithium salt, wherein the organic solvent mixture comprises 20 to 60% by volume of ethylene carbonate, 5 to 30% by volume of propylene carbonate, and 20 to 70% by volume of methylpropyl carbonate.

2. The organic electrolyte according to claim 1, wherein the content of the mixture of ethylene carbonate and propylene carbonate is 25 to 65% by volume.

3. The organic electrolyte according to claim 2, wherein the lithium salt is at least one compound selected from the group consisting of LiPF₆, LiBF₄, LiAsF₆, LiClO₄, CF₃SO₃Li, LiC(CF₃SO₂)₃, LiN(C₂F₅SO₂)₂, and LiN(CF₃SO₂)₂.

4. The organic electrolyte according to claim 1, wherein the lithium salt is at least one compound selected from the group consisting of LiPF₆, LiBF₄, LiAsF₆, LiClO₄, CF₃SO₃Li, LiC(CF₃SO₂)₃, LiN(C₂F₅SO₂)₂, and LiN(CF₃SO₂)₂.

5. A lithium secondary battery comprising:

a cathode including a lithium-containing metal oxide;

an anode including one of metallic lithium, a lithium alloy, and a carbon material; and

an organic electrolyte containing an organic solvent mixture and a lithium salt, wherein the organic solvent mixture comprises 20 to 60% by volume of ethylene carbonate, 5 to 30% by volume of propylene carbonate, and 20 to 70% by volume of methylpropyl carbonate.

6. The lithium secondary battery according to claim 5 wherein the content of the mixture of ethylene carbonate and propylene carbonate is 25 to 65% by volume.