The present research is oriented toward the task of developing improved electrolytes for H-2/O-2 fuel cells. A new type of glass electrolyte, consisting of various amounts of phosphomolybdic acid (PMA) doped onto a constant amount of titanium oxide (TiO2) in the silicaphosphate gels has been prepared by a sol-gel technique. The effect of PMA on the properties of the glass composite membrane were investigated by means of Fourier transform infrared, N-2-adsorption/desorption tests, thermogravimetric and differential thermal analysis, proton conductivity, and hydrogen permeability measurements. An average pore size of about 2.5 nm was determined by the Brunauer-Emmett-Teller method. This new class of electrolytes was found to be stable up to 400 degrees C and displayed a high proton conductivity, i.e., 6.29x10(-3) S/cm at 90 degrees C and 70% relative humidity, as well as mechanical strength. These properties proved that these glass electrolytes were very good candidates in membranes for H-2/O-2 low-temperature fuel cells. The electrochemical behavior of such novel PMA/TiO2-P2O5-SiO2 glass membranes was studied in an environment of hydrogen and oxygen gas at room temperature, and the results are presented and discussed. (c) 2007 The Electrochemical Society.