A study of cross-linked PEO gel polymer electrolytes using bisphenol A ethoxylate diacrylate: ionic conductivity and mechanical properties

Ionic conductivity, mechanical stability and electrochemical property were examined on the poly ethyleneoxide (PEO) based cross-linked gel polymer electrolyte. Bisphenol A ethoxylate diacrylates (BPAEDA) with different numbers of ethylene oxide units (n = 4, 15) were used as cross-linkers. The curing kinetics of the cross-linker was examined by an FIF-IR study with two types of initiators and at different curing temperatures. Higher conductivity was observed for the longer ethylene oxide unit. Conductivity of the polymer electrolyte prepared from BPAEDA (n = 15) and liquid electrolyte (70 wt.%) was 3.47 x 10(-3) S/cm at 30 degreesC. Improved tensile strength and elongation at break were realized from the polymer electrolyte using BPAEDA as a cross-linker. Electrolyte having higher cross-linking density showed higher tensile strength, but showed decreased flexibility. The stability of the polymer electrolyte against electrochemical oxidation could be extended to larger than 4.5 V (versus Li/Li+). Lithium cycling efficiency of the polymer electrolyte was about 80%. (C) 2003 Elsevier Science B.V All rights reserved.