Our proton conductivity estimate of 3135 mS/cm at 800 K for DSG is two times larger than the estimate for SSG of 1568 mS/cm . Assuming that proton self-diffusivities are the same for DSG as in SSG for all other temperatures, we obtain a proton conductivity of 627 and 1881 mS/cm at 300 K and 400 K, respectively, based on D s values computed by Achar et al. for SSG. Nafion under hydrated conditions has a significantly lower proton conductivity of 300 mS/cm at 380 K, and drops drastically to 35 mS/cm at a slightly lower temperature of 330 K . Other nearly anhydrous proton conducting materials like polysulfone only attain conductivities of 142 mS/cm at 450 K . Thus, DSG is predicted to have much higher proton conductivities than other materials.