The proton diffusion coefficient for both fresh and heat-treated (140 and 230 degrees C, respectively) alpha and beta-PbO2 electrodes was estimated at room temperature using Galvanostatic Intermittent Titration Technique (GITT). PbO2 samples were prepared by electroformation of cured plates. HSbO3 center dot xH(2)O with a conductivity of 3.29 x 10(-3) Omega(-1) cm(-1), was used as solid protonic conductor (SPC) electrolyte. It was found that when structural water is removed, the capacity of both alpha and P-PbO2 electrodes decreases and the ohmic drop increases. The departure of structural water affects considerably the value of proton diffusion coefficient. (c) 2005 Elsevier B.V. All rights reserved.