TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The anion of the tetravalent metal salt preferably comprises carboxylates, chlorides or alkoxides.Preferred Solvent: The organic solvent comprises protonable solvents, especially N,N-dimethylformamide, N-methyl-2-pyrrolidone, dioxane, dimethylsulfoxide, acetamide, acetonitrile, and/or various alkanols, commonly used for dissolving the proton conducting ionomers of the state of the art.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The tetravalent metal salt comprises zirconium, titanium, tin, and/or cerium (particularly zirconyl propionate or chloride). It is preferably phosphate-phosphonates, for the filling of pores. The phosphate-phosphonates comprise Zr(O-3P-CH2-PO3H2)2 and compounds of the series Zr(O3P-OH)2-n(O3P-C6H4-SO3H)m and Zr(O3P-C6H4-SO3H)2-n(O3P-CH2-PO3H2)n.n = 0.1-1.5.Preferred Condition: The phosphate-phosphonates exhibit proton conductivity greater than 10-2 S cm-1 at 70degreesC and 95% relative humidity.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The polymeric porous membrane comprises chemically and/or thermally stable polymers, especially polytetrafluoroethylene, polyvinylidene fluoride, polyesters, polyethersulfones, or fluoroelastomers.The nano-polymers comprise nano-particles of tetravalent metal salts, preferably phosphate-phosphonates, dispersed in the matrix of organic or inorganic polymers soluble in the same solvents. The organic polymeric matrix is that of a proton conducting ionomer. It is a synthetic ionomer of the state of the art, comprising perfluorosulfonic polymers, sulfonated polyetherketones, sulfonated polyetherketones, or sulfonated polyvinylidenfluoride.Preferred Condition: The porous membranes have a pore dimensions of 0.02-20, preferably 0.4-2 mum; and porosity of greater than 10, preferably 65-90%. Preferred Definition:    -G = -OH, -R2-SO3H, or -R2-PO3H2;where    -R2- = organic group, preferably linear chain, i.e. -(CH2)m and -(CF2)m-;    -R1- = arylene group comprising -C6H4-, -C6H4-, CH2- or -C6H4-CF2-;    -X = -SO3H, -PO3H2 or -COOH.    EXAMPLE - Zirconyl propionate (20.6 g) was dissolved in N-methyl 2-pyrrolidone (NMP). Separately, anhydrous sulfophenylenphosphonic acid (23.8 g) and anhydrous phosphoric acid (9.8 g) were dissolved in NMP. The former solution was slowly added under stirring at room temperature, to the last solution. A clear solution was obtained. The solution was warmed at at least 80 degrees C. A formation of a compact and transparent gel was observed (less than 30 minutes). The solid obtained by evaporation of the solvent at 80 degrees C did not contain appreciable amount of propionates, but the presence of large amount of NMP was still evident. When the solvent was completely eliminated at 130-140 degrees C, a solid of composition Zr()O3P-OH))O3P-C6H-4-SO3H) was obtained. The interlayer distance of this compound, determined by x-ray powder diffraction pattern was 1.9 nm. The protonic conductivity was 3.2x10-2 S cm-1 at 100 degrees C and 95% relative humidity.