NOVELTY - Covalently cross linked (composite) polymer or polymer membrane (I) (comprising: one or more polymers (precursors of cation exchange groups or sulfinate groups), optionally covalently cross-linked by difunctional, trifunctional or oligofunctional haloalkanes or haloaromatics, which have been reacted with sulfinate groups, alkyl amino compounds (which have been reacted with sulfinate groups) and/or alkyl diamino compounds (which have been reacted with sulfinate groups); and tectosilicates and/or phyllosilicates) is new.    USE - (I) is useful: for producing energy on an electrochemical route; as a component of membrane fuel cells (hydrogen or direct methanol fuel cells) at temperatures of 0-180degreesC; in electrochemical cells, in secondary batteries and in electrolytic cells; and in membrane separation processes such as gas separation, pervaporation, perstraction, reverse osmosis, electrodialysis and diffusion dialysis (claimed).    ADVANTAGE - (I) is compatible with the ion conductive polymer (blend) component. (I) exhibits good mechanical stability. (I) are not moistened or slightly moistened when used with gases.    DETAILED DESCRIPTION - Covalently cross linked polymer or covalently cross-linked polymer membrane (I) (comprising: one or more polymers (precursors of cation exchange groups, sulfonyl compound of formula (SO2M), phosphonyl compound of formula (POM2) and or carbonyl compound of formula (COM) or sulfinate groups of formula (SO2Me)) and optionally covalently cross-linked by difunctional, trifunctional or oligofunctional haloalkanes or haloaromatics, which have been reacted with sulfinate groups of formula (SO2Me) (having cross-linking bridge of polymer-SO2-Y1-SO2, in the polymer/polymer blend/polymer membrane), alkyl amino compounds of formula (Hal-(CH2)x-NHR) (which have been reacted with sulfinate groups and having cross-linking bridge of polymer-SO2-(CH2)x-NR-SO2-polymer, in the polymer/polymer blend/polymer membrane) and/or alkyl diamino compounds of formula (NHR-(CH2)x-NHR) (which have been reacted with sulfinate groups and having cross-linking bridge of polymer-SO2-NR-(CH2)x-NR-SO2-polymer, in the polymer/polymer blend/polymer membrane); and tectosilicates and/or phyllosilicates, where the tectosilicates and/or phyllosilicates present can be optionally functionalized) is new.    M = halo, OR or NR2;    R = alkyl, hydroxyalkyl or aryl;    Me = H, Li, Na, K, Cs, other metal cations or ammonium ions;    Y1 = cross-linking bridge, -(CH2)x, arylene, -(CH2)x-arylene or -CH2-arylene-CH2-;    X = halo or OR; and    x = 3-12.    An INDEPENDENT CLAIM is included for the preparation of (I).