Ultraviolet-cured polyethylene glycol diacrylate/polyvinylidene fluoride blend gel polymer electrolytes

Abstract

We developed a novel UV-cured blend gel polymer electrolyte based on polyethylene glycol diacrylate (PEGDA) and polyvinylidene fluoride (PVdF). UV-curing of the homogeneous liquid solution composed of PEGDA oligomer and PVdF/dimethlyformamide resulted in highly miscible blend films. Thus, PEGDA/PVdF (5/5) blend electrolyte showed the highest room-temperature conductivity of ca. 3 mS/cm and enhanced tensile elongation of ca. 60%. Also, all blend electrolytes were electrochemically stable up to 4.7 V vs. Li/Li+. Li/(PEGDA/PVdF)/LiCoO2 cell (2 × 2 cm) retained more than 91% of its initial discharge capacity after 50 cycles at C/3 rate (2 mA/cm2) and delivered ∼70% of full capacity with an average load voltage of 3.6 V at C/1 rate. The good electrochemical properties and high mass productivity of UV-cured PEGDA/PVdF blend gel electrolyte make it suitable for large-scale lithium polymer batteries.