Several unsaturated polyethers have been prepared by a polycondensation route, from alpha, omega dihydroxy oligoethers, and cross-linked by free-radical initiation. The ionic conductivities and thermal behavior of LiTFSI/network electrolytes have been investigated and show that conductivities depend on the nature of the solvating oligomeric blocks, the maxima corresponding to poly(oxyethylene) based networks. Oligomeric poly(oxypropylene) and poly(oxytetramethylene) blocks however provide a quite satisfactory conductivity level.