| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrolyte for a secondary battery with high retainability and good stability by forming a matrix with a copolymer, containing a polymeric unit of vinylidene fluoride and the specific polymeric unit, and forming a polymer electrolyte containing a solution comprising a lithium salt solute and a solvent capable of dissolving the lithium salt. SOLUTION: The weight ratio of a polymeric unit of vinylidene fluoride in a copolymer constituting a matrix of a polymer electrolyte and a polymeric unit represented by -(CXY-CZ(OR<1> ))- (where X, Y, Z may be identical or different, and are independently a hydrogen atom, fluorine atom, or chlorine atom, and R<1> is a monovalent organic group having 1-22 carbon atoms) is preferably 10/90-97/3. As the lithium salt solution, use of at least one of lithium salts using ClO4 <-> , CF3 SO3 <-> , BF4 <-> or the like as an anion is preferable. |
