1-Butyl-3-methylimidazolium trifluoroacetate ionic lig. and ethoxylated bisphenol F diacrylate and ethoxylated bisphenol A dimethacrylate crosslinking monomers (80:20 mass ratio) were used to prep. in situ solid polymer electrolytes by photopolymerization. Ionic cond. of the prepd. electrolyte 1.1-1.6.10(-2) S/cm was significantly higher than the ionic cond. of the neat ionic lig. (0.326.10(-2) S/cm). The specific capacity of electric double layer capacitors based on electrolyte was 50-70 F/g.