Polymer electrolyte

• US 6,509,122 B1
• Filed: 03/16/2000
• Issued: 01/21/2003
• Est. Priority Date: 03/17/1999
• Status: Expired due to Fees

• Current Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Original Assignee: Noboru Oyama
• Inventors: Oyama, Noboru
• Primary Examiner(s): Chaney, Carol
• Assistant Examiner(s): DOVE, TRACY MAE
• Application Number:
  US09/527,569
• Time in Patent Office: 1,041 Days
• Field of Search: 429/303, 429/336, 429/338, 429/341, 429/339, 429/304
• US Class Current: 429/303
• CPC Class Codes: C08F 290/062 Polyethers
• CPC Class Codes: C08G 65/3322 acyclic
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 71/02 Polyalkylene oxides
• 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 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/22 Immobilising of electrolyte
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A polymer electrolyte for lithium secondary batteries in which growth of lithium dendrites is suppressed is disclosed, batteries exhibiting excellent discharge characteristics in low to high temperature, comprising a polymer gel holding a nonaqueous solvent containing an electrolyte, wherein the polymer gel comprises (I) a unit derived from at least one monomer having one copolymerizable vinyl group and (II) a unit derived from at least one compound selected from the group consisting of (II-a) a compound having two acryloyl groups and a (poly)oxyethylene group, (II-b) a compound having one acryloyl group and a (poly)oxyethylene group, and (II-c) a glycidyl ether compound, particularly the polymer gel comprises monomer (I), compound (II-a), and a copolymerizable plasticizing compound are disclosed.

Claims

1. A polymer electrolyte comprising:

a polymer gel holding a nonaqueous solvent containing an electrolyte, wherein said polymer gel comprises a polymer containing (I) monomeric units derived from at least one compound having one copolymerizable vinyl group and (II) monomeric units derived from a compound (II-a) represented by one of formulae (1) and (2);

2. The polymer electrolyte according to claim 1, wherein said compound (II-a) has a weight average molecular weight of 5000 or less.

3. The polymer electrolyte according to claim 1, wherein said electrolyte contains at least one lithium salt selected from the group consisting of CF₃SO₃Li, S₄F₉SO₃Li, (CF₃SO₂)₂NLi, (CF₃SO₂)₃CLi, LiBF₄, LiPF₆, LiClO₄, and LiAsF₆.

4. The polymer electrolyte according to claim 3, wherein said nonaqueous solvent comprises at least one compound selected from the group consisting of a cyclic carbonate, an acyclic carbonate, a cyclic ester, an amide compound, and a nitrile compound.

5. The polymer electrolyte according to claim 1, wherein said electrolyte contains at least one salt selected from the group consisting of CF₃SO₃Li, S₄F₉SO₃Li, (CF₃SO₂)₂NLi, (CF₃SO₂)₃CLi, LiBF₄, LiPF₆, LiClO₄, LiAsF₆, these salts with the lithium ion displaced with other alkali metals, a tetraalkylammonium salt, a tetraalkylfluoroborate, a tetraalkylphosphonium fluoroborate, a tetraalkylphosphonium trifluorosulfonate, an alkylpyridinium salt, and an N-alkylimidazole salt.

6. The polymer electrolyte according to claim 4, wherein said nonaqueous solvent contains an organic solvent having a donor number of 0.1 or greater and a dielectric constant of 10.0 or greater.

7. The polymer according to claim 6, wherein said organic solvent comprises at least one compound selected from the group consisting of a cyclic carbonate, an acyclic carbonates, a cyclic ester, a nitrile compound, an acid anhydride, an amide compound, a phosphate compound, and an amine compound.