Preparation and Characterization of Nafion®/Hydrated Phosphor‐Silicate Hybrid Membranes for the Direct Methanol Fuel Cell

Abstract

AbstractThe characteristics of Nafion®/hydrated phosphor‐silicate hybrid membranes for direct methanol fuel cells (DMFCs) are investigated. The effect of the ratio of the hydrated phosphor‐silicate to Nafion® on the morphology, thermal and chemical stabilities, crystalline structure, proton conductivity, and methanol permeability of the hybrid membrane are studied. The thermal and chemical stability as well as the methanol impermeability of the hybrid membrane are superior to those of the Nafion® 117 membrane. The hybrid membranes show higher proton conductivities than the hydrated phosphor‐silicate glass membranes but slightly lower conductivities compared to the Nafion® 117 membrane. It is shown that the crystalline structure of the hybrid membranes changes with the SiO2‐P2O5 particle content. The direct methanol fuel cell with the hybrid membrane shows a maximum power density of about 13.42 mW cm–2 under the conditions of 20 °C in air and 2 M methanol feed solution. The single cell of the hybrid membrane also shows a high open circuit voltage of 0.66 V, indicating that the methanol crossover of the hybrid membranes is low. This shows that the hybrid membrane is indeed a good electrolyte candidate for direct methanol fuel cell applications.