Engineered metal coverage of anode catalyst layer enhancing cell reversal tolerance for proton exchange membrane fuel cells

Anode cell reversal, which is caused by fuel starvation, poses a great threat to the durability of proton exchange membrane fuel cells. Commercially, iridium oxide or iridium is applied to boost oxygen evolution reaction, which alleviates carbon corrosion and protects the catalyst layer structure. However, the key factors that affect the anti-reversal ability and the interaction between Pt, Ir, and carbon support are still unclear. Hence, we systematically studied the performance using three typical carbon supports with three metal contents and different metal deposition orders by experiments and model calculations. A new parameter, "relative metal coverage", is put forward to evaluate and predict the anti-reversal ability, showing higher relative metal coverage results in a longer reversal time and lower polarization performance degradation rate. Typically, only a 15.5% polarization performance loss after 1700 mins reversal time when the relative metal coverage of high metal content Ir/Pt/Super P anode is one. The results suggest that increasing relative metal coverage is a practical approach to improve reversal tolerance and provide new insights into the reversal tolerant anodes design.