A polymer electrolyte includes a polymer matrix including a polymer having a repeating unit represented by the formula




and an ionic liquid. R1 to R3 are each one of a substituted or unsubstituted C1-C12 alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or combinations thereof. Each R4 is one of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C1-C10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C5-C14 heteroaryl group, or combinations thereof. Substituents of R1 to R4 are each one of a halogen group, a cyano group, a nitro group, a C1-C8 alkyl group, or combinations thereof, x is an integer of 1 to 8, and n is an integer of 60 to 3200.