Electrochemical properties of poly(tetra ethylene glycol diacrylate)-based gel electrolytes for lithium-ion polymer batteries

The precursor for a gel polymer electrolyte (GPE) consisted of tetra (ethylene glycol) diacrylate monomer, benzoyl peroxide, and 1.1 M LiPF6/EC:PC:EMC:DEC (30:20:30:20 wt.%). LiCoO2/graphite cells were prepared and their electrochemical properties were evaluated at various current densities and temperatures. The viscosity of the precursor containing 5 vol.% tetra (ethylene glycol) diacrylate monomer was around 4.6 mPa s. The ionic conductivity of the gel polymer electrolyte at 20 °C was around 6.34×10−3 S cm−1. The gel polymer electrolyte had good electrochemical stability up to 4.5 V versus Li/Li+. The capacity of the cell at 2.0 C rate was 74% of the discharge capacity at 0.2 C rate. The capacity of the cell at temperature of −10 °C was 81% of the discharge capacity at temperature of 20 °C. Discharge capacity of the cell with gel polymer electrolyte was stable with charge–discharge cycling.