Cerium based metal-organic framework as the efficient radical quencher for proton exchange membrane fuel cells

Durability is one of the most key problems for the widespread commercialization of proton exchange membrane fuel cells (PEMFCs). Proton exchange membranes (PEMs) are pivotal components of the PEMFCs and their chemical stability is thus an important for the PEMFCs reliability. The incorporation of Ce-based radical quenchers such as ceria in PEMs can obviously alleviate the chemical deterioration of PEMs. Nevertheless, cell performance may decrease due to the presence of Ce-based radical quenchers. Therefore, a trade-off between cell performance and chemical stability of Ce-based radical quenchers containing PEM appears. To solve this issue, we developed a Ce-based metal organic framework Ce-BTC MOF with high radical trapping and proton-conducting properties. The Ce-BTC MOFs are introduced into the PFSA membrane to enhance the chemical stability and proton conductivity of the PFSA membrane. The PFSA/Ce-BTC membrane showed a maximum power density of 1.71 W/cm2 at 75 °C under 80％RH. After OCV test, PFSA/Ce-BTC membrane exhibited a decay of 0.56 mV/h after 120 h; pristine PFSA and Nafion membrane exhibited accelerated decay (for pristine PFSA, 1.72 mV/h; for Nafion membrane, 2.36 mV/h). Therefore, introduction of Ce-BTC MOFs offers an active defence approach to enhance the chemical stability of PEMFCs without sacrificing their cell performance.