The research group at the University of Pavia is involved in preparation and characterization of polymer electrolytes belonging to two families: (i) the solvent free, polyether-based, and (ii) the gel ones. in this payer our most recent developments are summarized, and emphasis is given on the physico-chemical properties of these two electrolyte families, which strongly influence their utilization in electrochemical devices. (C) 2000 Elsevier Science B.V. All lights reserved.