Abstract: The present invention relates to a polyalkylene oxide based polymer composition for solid polymer electrolytes having superior mechanical properties and ionic conductivity by comprising a cross-linking agent with at least two functional groups of phenyl alkyleneglycol acrylate substitited in core molecules; a softener of polyalkyleneglycol alkylether alkyl(metha)acrylate; a plasticizer of polyalkyleneglycol dialkylether; a initiator and lithium salt thus can be useful as an electrolyte for a high capacity lithium-polymer secondary battery for load leveling or electric vehicles as well as an electrolyte for a small capacity lithium-polymer secondary battery for portable information terminals such as a cellular phone and a notebook computer, and electronic products such as a camcorder.

Abstract: A solid polymer electrolyte includes a crosslinking agent, a poly(alkylene glycol) alkyl ether alkyl (meth)acrylate, a lithium salt and a curing initiator. The crosslinking agent includes a compound represented by formula (I): wherein A is oxygen, COO, alkyl of C1-4, or a single bond, R is a 6-membered aliphatic, aromatic or heterocyclic group, Ra, Rb and Rc independently are a linear or branched alkyl group of C1-10, Rd, Re and Rf independently are H or a methyl group, and p, q and r independently are an integer of 1 from 20. The poly(alkylene glycol) alkyl ether alkyl (meth)acrylate is represented by formula (II) wherein R1 and R2 independently are a linear or branched aliphatic or aromatic group of C1-10, R3, X, Y, Z independently are H or a methyl group, and p, q and r independently are an integer from 1 to 20.