An electrochemical cell is provided with first (10) and second (11) electrodes and a solid polymer electrolyte (15) disposed therebetween. The solid polymer electrolyte is preferably fabricated by providing a linear powdered polymeric precursor material which is thereafter heated to temperatures sufficient to drive off moisture and in the presence of an electrolyte active species. The electrolyte active species is preferably an acidic electrolyte active species which has the effect of protonating the powdered polymeric precursor material. Electrochemical cells fabricated using these devices demonstrate performance characteristics far better than those available in the prior art.