Aquivion Hybrid Membranes Modified with Hydrated Oxides MO2 (M = Si, Ti, Ce): Transport Properties and Chemical Stability

Abstract

Due to the rapid development of hydrogen energy, increased attention is paid to the preparation of polymer ion-exchange membranes for low-temperature fuel cells. The paper presents the results of studying transport properties and chemical stability of hybrid materials based on a perfluorosulfonic acid polymer membrane with a short side chain Aquivion and hydrated oxides of silicon, titanium, and cerium obtained by the in situ method. Modification of the Aquivion membrane with hydrated silicon and titanium oxides leads to an increase in the proton conductivity of the membranes by 10–40% but, in the case of silica, is accompanied by a gain in gas permeability. The advantage of hybrid membranes Aquivion + SiO₂ is their higher conductivity at reduced humidity (RH = 32%) compared to Aquivion. It is found that membranes based on perfluorosulfonic acid polymers with a short side chain (Aquivion) have higher chemical stability than those with a long one (Nafion^®212). The introduction of hydrated titanium and cerium oxides leads to the preservation of high proton conductivity after membranes treatment with Fenton’s reagent along with their high chemical stability due to the ability of dopants to capture free radicals.