Conductivities of 2 x 10(-6) S cm(-1) at 50 degrees C and 10(-5) S cm(-1) at 75 degrees C have been measured in glassy polymer-in-salt mixtures (T-g between 50 degrees C and 70 degrees C) based on polyacrylonitrile and lithium triflate (LiTf), where the salt can comprise more than 70 wt.% (60 mol.%) of the mixture. These materials have been prepared by a novel solvent free technique involving compression moulding.