Proton conductivity was examined in P2O5-ZrO2-SiO2 glasses prepared by sol-gel method and characterized for structural, nitrogen adsorption-desorption and thermal measurements. The amorphous phases of our glasses were confirmed by X-ray diffraction (XRD) analysis. Fourier transform infrared (FTIR) spectroscopy studies identified the presence of Si-O-Si and Zr-O-Si bond structures on glass surface. The differential thermal analysis and thermal gravimetric analysis (TGA/DTA) results showed decomposition in the temperature range from 40 to 300 degrees C. A distribution of average pore size 2.5 nm, pore volume 0.26 cm(3) g(-1) and surface area 407 m(2) g(-1) were obtained by pore analysis. Proton conductivities of all samples (thickness 0.5-1 mm) increased with an increase in relative humidity (RH) (40-90%), indicating that continuous paths suitable for proton conduction were formed in the glasses heat treated at 600 degrees C due to the adsorption of water. The temperature dependence of the conductivity for all compositions increases with increasing temperature range of 30-90 degrees C at relative humidity 70%. An open circuit potential of similar to 1 V and a maximum power density of about 0.9 mW cm(-2) were achieved at 30 degrees C with relative humidity 30%. (c) 2005 Elsevier B.V. All rights reserved.