Thermally stable polymer electrolyte plasticized with PEG-borate ester for lithium secondary battery

A novel polymer electrolyte was prepared by employing poly(ethyleneglycol) (PEG)borate ester as plasticizer to the electrolyte composed of poly(ethyleneglycol) methacrylate (PEGMA) and lithium bis-trifluoromethanesulfonimide (LiTFSI). The PEG-borate ester shows good thermal stability and high flash point. The ionic conductivity of the polymer electrolyte increases with increasing amount of the PEGborate ester and exhibits greater value than 10-4 Scm-1 at 30°C and 10-3 Scm-1 at 60°C.