A cage polyhedral oligomeric silsesquioxane (POSS) was functionalized in reaction with limonene or pinene and used as an additive to poly(vinylidene fluoride)/hexafluoropropylene copolymer matrix and studied for physicochem. and electrochem. parameters as hybrid gel electrolytes to Li-polymer batteries. The hybrid gel electrolytes showed an improved solvent uptake and significantly higher cond. as compared to membranes without POSS.