(JP8503574-W)      Electrochemical cell has (a) a pair of electrodes, each with catalyst deposited on a porous carrier of C particles bonded with a binder, the pores of which allow percolation of fluid through the electrode; (b) a membrane film (I) of hydrophilic, proton-conducting polymer material acting as electrolyte and separator, with an intermediate film (II) between (I) and the catalyst; and (c) means of supplying and discharging a fluid to/from at least one electrode and contacting the electrodes.    The novel features are that: (1) (I) is based on an opt. substd. polyolefin, vinyl polymer or their copolymers with radiation-grafted terminal sulphonated vinyl gps., which are derived from opt. substd. vinyl monomers (III); and (2) (II) consists of a proton-conducting hydrophilic copolymer of poly(perfluoroalkylene) substd. by ion exchanging gps. and poly(perfluoroalkylene) substd. with non-ion exchanging gps.    The prepn. of (I) is also claimed.    USE -   The cell is operated as a fuel cell, operating with gaseous fuel and gaseous oxidant, which may be mixed with inert gases; an electrolytic cell; or either at will (claimed).    ADVANTAGE -   The cell can operate above room temp., uses more economical (I) material than usual and has satisfactory long-term stability.    (EP667983-B1)      Electrochemical cell has (a) a pair of electrodes, each with catalyst deposited on a porous carrier of C particles bonded with a binder, the pores of which allow percolation of fluid through the electrode; (b) a membrane film (I) of hydrophilic, proton-conducting polymer material acting as electrolyte and separator, with an intermediate film (II) between (I) and the catalyst; and (c) means of supplying and discharging a fluid to/from at least one electrode and contacting the electrodes.    The novel features are that: (1) (I) is based on an opt. substd. polyolefin, vinyl polymer or their copolymers with radiation-grafted terminal sulphonated vinyl gps., which are derived from opt. substd. vinyl monomers (III); and (2) (II) consists of a proton-conducting hydrophilic copolymer of poly(perfluoroalkylene) substd. by ion exchanging gps. and poly(perfluoroalkylene) substd. with non-ion exchanging gps.    The prepn. of (I) is also claimed.    USE -   The cell is operated as a fuel cell, operating with gaseous fuel and gaseous oxidant, which may be mixed with inert gases; an electrolytic cell; or either at will (claimed).    ADVANTAGE -   The cell can operate above room temp., uses more economical (I) material than usual and has satisfactory long-term stability.