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Thermally Stable Gel Polymer Electrolytes

2003; Institute of Physics; Volume: 150; Issue: 4 Linguagem: Inglês

10.1149/1.1556592

1945-7111

Min‐Kyu Song, Young-Taek Kim, Yong‐Tae Kim, Byung Won Cho, Branko N. Popov, Hee‐Woo Rhee,

Supercapacitor Materials and Fabrication

To prepare miscible polyethylene glycol diacrylate/polyvinylidene fluoride (PEGDA/PVdF) blend gel polymer electrolytes, low molecular weight liquid PEGDA oligomer was mixed with PVdF-HFP dissolved in ethylene carbonate/dimethyl carbonate/ liquid electrolytes, and then cured under ultraviolet irradiation. Room temperature conductivity of PEGDA/PVdF blend films was found to be comparable to that of PVdF-HFP gel polymer electrolytes, and they were electrochemically stable up to 4.6 V vs. Scanning electron micrographs revealed that PEGDA/PVdF blend electrolytes have pore size intermediate between dense PEGDA and highly porous PVdF-HFP. It was confirmed by weight change measurement that liquid electrolyte was likely to evaporate through large pores in PVdF-HFP at 80°C, while PEGDA/PVdF blend showed better liquid electrolyte retention ability. This result was in good agreement with more stable interfacial properties of PEGDA/PVdF blend at 80°C in ac impedance analysis. Consequently, both PVdF-HFP and PEGDA/PVdF gel polymer electrolytes delivered similar discharge capacity at room temperature, but PEGDA/PVdF blend gel polymer electrolyte showed much better cycle performance than pure PVdF-HFP at 80°C. © 2003 The Electrochemical Society. All rights reserved.