Enhanced Performance of Sulfonated Poly(ether ether Ketone) Hybrid Membranes by Introducing Sulfated MOF-808/Graphene Oxide Composites

High-performance composite proton exchange membranes (PEMs) [SP/SO4-metal-organic framework (MOF)-808@GO] consisting of sulfonated poly(ether ether ketone) and superacid SO4-MOF-808@GO are fabricated in this work. The composite PEMs obtain higher proton conductivity and fuel cell performance than pure SP. SO4-MOF-808 grains are uniformly deposited on the GO surface, which prevents the agglomeration of the MOF grains and thus ensures a good dispersity of MOFs in the membranes. The superacid sites in SO4-MOF-808@GO bind abundant water, which enhances proton transfer at a low humidity. The water retention ability of the SP/SO4-MOF-808@GO composite membrane outperforms that of pure SP. Benefiting from the optimized SO4-MOF-808@GO structure, the proton conductivity of SP/SO4-MOF-808@GO is up to 0.196 S cm–1 under 70 °C–90% RH and 0.0434 S cm–1 under 90 °C–40% RH, 2.63- and 7.44-fold that of pure SP, respectively. Moreover, the single cell assembled with SP/SO4-MOF-808@GO attains a 70.28% increase over pure SP in power density. Collectively, the results suggest that the SP/SO4-MOF-808@GO membrane has potential application in PEMs.