TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Materials: The substrate consists of refractory ceramic fibers with polycrystalline microstructure. It has a high content of alumina, silicon carbide or nitride or zirconium oxide and preferably consists of alumina fibers or filaments containing 0-30% silica. It is in the form of woven or nonwoven fabric of fibers and/or filaments with a diameter of 0.5-150 (20-70) mum and/or threads with a diameter of 5-100 (10-30) mum.The woven material has a mesh size of 5-500 (10-200) mum, whilst the nonwoven is 5-100 (10-30) mum thick and has a porosity of 10-60 (20-45)% and average pore diameter of less than 20 (less than 250) nm.    TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Electrolyte Membrane: The membrane is stable at less than 80 (preferably at less than 140)degreesC and the membrane electrode unit can be operated at these temperatures. The composite is 5-150 mum thick (10-50 mum for woven and 10-30 mum for nonwoven) and can tolerate flexure through a radius of at least 100 (at least 5) mm.The conductivity of the membrane is less than 2 (preferably less than 23) mS/cm at room temperature and 35% relative humidity.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The proton-conducting material comprises(1) an immobilized hydroxysilylalkyl-sulfur or -phosphorous acid (I) or salt and optionally an oxide (II) of aluminum (Al), silicon (Si), titanium (Ti), zirconium (Zr) and/or phosphorus (P);(2) an ionic liquid (III), optionally containing a Bronsted acid (IV) (e.g. sulfuric, phosphoric, perchloric, nitric, hydrochloric, sulfurous, phosphorous acid or ester or mono- or polymeric organic acid); and(3) (IV) and (II).(I) or its salt is immobilized with a hydrolyzed P compound, (oxy)nitrate, (oxy)chloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or metalloid, e.g. diethyl phosphite, titanium propylate, tetraethyl orthosilicate or zirconium nitrate. The proton-conducting component of the anode, cathode and/or composite comprises (i) (I) or salt and optionally (II) and/or (ii) (IV) and (II) and optionally (iii) inorganic oxides, phosphates, phosphides, phosphonates, sulfates, sulfonates, vanadates, antimonates, stannates, plumbates, chromates, tungstates, molybdates, manganates, titanates, silicates, aluminosilicates and aluminates of Li, Na, K, Mg, Ca, Al, Si, Ti, Zr, Y, P, V, W, Mo, Cr, Mn, Fe, Co, Ni, Cu, Zn and/or Ce. In the composite, it may be an ionic liquid, which can contain (IV).Preferred catalysts are platinum metals and their alloys (Pt, Pd, Ru), optionally with a transition metal (Ni, Co) complex of a (substituted) phthalocyanine as cocatalyst.Preferred additives include ammonium (bi)carbonate as pore former and carbon black, graphite, carbon, (activated) charcoal and metal oxides as carrier.Production: (Claimed). The membrane is obtained by infiltrating the permeable composite with the following::(1) (a) (III);(2) (b1) a mixture containing an immobilizable (I) or salt; or(3) (b2) a mixture containing (IV) and/or (I) or its salt and also a sol forming a precursor for (II); and(4) consolidation of the infiltrated material and optionally infiltration with (III) if (b1, b2) is used.The membrane electrode unit is produced by applying anode and cathode coating compositions (containing condensable component imparting proton conductivity, catalyst (precursor), optionally carrier, optionally pore former) to opposite sides of an electrolyte membrane agents to give firmly bonded, porous, proton-conducting anode and cathode layers.Preferred Production: The sol is obtained by hydrolysis of a hydrolyzable compound, preferably alcoholate, acetate, acetylacetonate, (oxy)nitrate, (oxy)chloride, carbonate of Al, Si, Ti, Zr and/or P or esters, preferably (m)ethyl and/or propyl phosphate or phosphite, preferably in a mixture of water and alcohol, then peptization to a sol. The mixture may contain other proton-conducting substances, preferably Ti and Zr phosphates and phosphonates, iso- and heteropoly-acids, tungstophosphoric or silicotungstic acid, nanocrystalline and/or crystalline metal oxides, preferably Al2O3, ZrO2, TiO2 or SiO2 powder. Infiltration is carried out by printing, pressing onto or into the substrate, rolling, spreading, brushing, dipping, spraying or pouring the mixture of the substrate. Infiltration may be repeated, optionally with intermediate drying, preferably at 50-200degreesC, and/or carried out continuously, preferably with warm composite. Consolidation involves heating to 50-800 (150-200)degreesC, preferably with warm or hot air or infrared or microwave radiation.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: Acids (I) are organosilicon compounds of formula, (((RO)y(R2)z)aSi(R1-SO3-)a)xMn+ (IA) or (((RO)y(R2)z)aSi(R1-Ob-P(OcR3)O2-)a)xMx+(IB):R1 = linear or branched 1-12 C alkyl, 5-8 C cycloalkyl, -(CH2)n-Phe-(CH2)m- or -(CH2)n-Cyc-(CH2)m-;Phe = phenylene;Cyc = cyclohexylene;n, m = 0-6;M = H, NH4 or a metal;x = 1-4;y = 1-3;z = 0-2;a = 1-3;(y+z) = 4-a;b, c = 0, 1;R, R2 = (m)ethyl, propyl, butyl or H; andR3 = M, (m)ethyl, propyl or butyl.Trihydroxysilylpropylsulfonic, trihydroxysilylpropylmethylphosphonic and dihydrosilylpropyldisulfonic acid are especially suitable.The impregnated material may also contain an ionic liquid with a cation selected from imidazolium, pyridinium, ammonium and phosphonium ions (optionally with alkyl, olefin or aryl substituent(s)) and nitrate, (H) sulfate, chloroaluminate, tetrafluoroborate, alkylborate (triethylhexylborate) or halophosphate (hexafluorophosphate) anion. EXAMPLE - Titanium tetraisopropylate (120 g) was added to deionized ice (140 g) with vigorous stirring to give a very finely-divided precipitate. After adding 25% hydrochloric acid (100 g), the mixture was stirred until it became clear, then aluminum oxide CT300OSG (RTM) (280 g) was added and stirring was continued for several days until the aggregates separated, giving suspension (A). A 10 mum thick ceramic nonwoven fabric of Al2O3 fibers was treated with a zirconium nitrate sol (30 wt.% ZrO2), which was bonded by tempering at 200degreesC. (A) was spread on a this material and dried in 10 seconds by blowing with air at 550degreesC. The resultant composite had a pore size of 0.2-0.4 mum and was not destroyed by bending through a radius of 5 mm. An inorganic permeable composite, obtained by applying a thin layer of (A) to this material, was dipped in a solution of 5% Silan 285 (RTM; a propylsulfonic acid triethoxysilane), 20% deionized water in 75% ethanol, which had been stirred at room temperature for 1 hour before use. After draining off excess solution, the composite was dried at 80-150degreesC, giving an electrolyte membrane.