Hybrid polymer electrolyte for lithium battery and method of preparing same

• US 6,395,430 B1
• Filed: 08/28/1998
• Issued: 05/28/2002
• Est. Priority Date: 08/28/1997
• Status: Expired due to Term

• Current Assignee: Samsung Display Devices Co., Ltd. (Samsung SDI Company Limited)
• Original Assignee: Samsung Display Devices Co., Ltd. (Samsung SDI Company Limited)
• Inventors: Cho, Jae-phil, Kim, Geun-bae, Park, Yong-chul
• Primary Examiner(s): Brouillette, Gabrielle
• Assistant Examiner(s): WILLS, MONIQUE M
• Application Number:
  US09/143,187
• Time in Patent Office: 1,369 Days
• Field of Search: 429/231.95,129,188,326,62.2,304,316 252/62.2
• US Class Current: 429/316
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0091 in the form of mixtures
• CPC Class Codes: H01M 6/181 with polymeric electrolytes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A hybrid polymer electrolyte includes a copolymer matrix of poly(vinyl chloride) and poly(vinylidene chloride) having a plurality of pores, and a solution of an alkali metal salt in an organic solvent entrained in the pores of the copolymer matrix. The pores of the copolymer matrix occupy 10 to 50 volume percent of the hybrid polymer electrolyte.

Claims

1. A hybrid polymer electrolyte comprising:

a copolymer matrix of poly(vinyl chloride) and poly(vinylidene chloride) having a plurality of pores that occupy 10 to 50 volume percent of the hybrid polymer electrolyte; and

a solution of an alkali metal salt in an organic solvent entrained in the pores of the copolymer matrix.

2. The hybrid polymer electrolyte of claim 1 wherein the pores of the copolymer matrix occupy 25 to 50 volume percent of the hybrid polymer electrolyte.

3. The hybrid polymer electrolyte of claim 1 wherein the alkali metal salt is a lithium salt.

4. The hybrid polymer electrolyte of claim 3 wherein the lithium salt comprises at least one compound selected from the group consisting LiClO₄, LiBF₄, LiCF₃SO₃, LiAsF₆, LiPF₆, and LiN(CF₃SO₂)₂.

5. The hybrid polymer electrolyte of claim 1 wherein the organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethylene carbonate, and mixtures thereof.

6. The hybrid polymer electrolyte of claim 1 wherein the copolymer matrix contains a 3:

1 mixture by weight of poly(vinyl chloride) and poly(vinylidene chloride).

7. The hybrid polymer electrolyte of claim 1 wherein the hybrid polymer electrolyte comprises 20 to 35 weight percent of the copolymer matrix, 20 to 35 weight percent of the alkali metal salt, and 30 to 60 weight percent of the organic solvent.

8. The hybrid polymer electrolyte of claim 1 wherein the organic solvent is a mixture of ethylene carbonate and propylene carbonate, the alkali metal salt is LiN(CF₃SO₂)₂, and the copolymer matrix contains a 3:

1 mixture by weight of poly(vinyl chloride) and poly(vinylidene chloride).

9. A lithium battery comprising a hybrid polymer electrolyte, the hybrid polymer electrolyte comprising:

a copolymer matrix of poly(vinyl chloride) and poly(vinylidene chloride) having a plurality of pores that occupy 10 to 50 volume percent of the hybrid polymer electrolyte; and

a solution of an alkali metal salt in an organic solvent entrained in the pores of the copolymer matrix.

10. A method of preparing a hybrid polymer electrolyte, the method comprising the steps of:

obtaining a solution by dissolving an alkali metal salt and an organic solvent in tetrahydrofuran;

obtaining a mixture by mixing a copolymer of poly(vinyl chloride) and poly(vinylidene chloride) with the solution;

forming the mixture into a film; and

evaporating off the tetrahydrofuran from the film.

11. The method of claim 10 wherein the alkali metal salt is lithium salt.

12. The method of claim 10 wherein the lithium salt comprises at least one compound selected from the group consisting LiClO₄, LiBF₄, LiCF₃SO₃, LiAsF₆, LiPF₆, and LiN(CF₃SO₂)₂.

13. The method of claim 10 wherein the organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethylene carbonate, and mixtures thereof.