Organic phosphonic acid modified SBA-15 assisted enhanced high-temperature proton exchange membrane fuel cell performance of polybenzimidazole membranes

To tackle the challenges of phosphoric acid (PA) leakage and suboptimal proton transfer efficiency in PA-polybenzimidazole (PBI) high-temperature proton exchange membranes (HTPEMs), this research has pioneered the development of a novel porous silicon material, DP/S15, which has been tailored through organic phosphonic acid modification. S15 or DP/S15 was utilized to fabricate PBI composite membranes and subjected these membranes to a thorough examination of their properties. The integration of DP/S15 into the membrane matrix notably enhanced acid uptake and facilitated the formation of a robust and extensive proton transportation network. This was largely attributable to the synergistic interaction between the organic phosphonic acid groups in DP/S15 and PA. As a result, the membranes incorporating DP/S15 exhibited a host of commendable properties, most notably their substantial mechanical strength , which registered at 89.80 MPa with undoped PA and 13.10 MPa with doped PA. Furthermore, theoretical analyses lent credence to the efficient adsorption between DP/S15 and phosphoric acid. Consequently, the composite membranes delivered superior performance metrics, evident in their high conductivity (reaching 57.7 mS cm −1 at 160 °C) and excellent PA retention capabilities (up to 89.5 %). Of paramount significance was the performance of the single fuel cell equipped with the PA-DP/S15-PBI composite membrane, which achieved a peak power density of 672.29 mW cm −2 . This figure impressively surpassed that of the pure PBI membrane by 262.23 mW cm −2 . In light of these promising outcomes, the PA-DP/S15-PBI composite membrane harbors significant potential for deployment in HT-PEMFCs.