▎ 摘　　要

NOVELTY - A composite polymer electrolyte for lithium secondary battery comprises branched polymer and 0.2-10 pts. wt. graphene oxide. USE - Composite polymer electrolyte for use in lithium secondary battery that is utilized in portable electronic instrument. ADVANTAGE - The composite polymer electrolyte has high ion conductivity, excellent stability and mechanical strength, and provides the lithium secondary battery with excellent charge and discharge performance, lifetime property, and high energy density. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a lithium secondary battery (2) a method for preparing a composite polymer electrolyte.