Ultra-low platinum loadings in polymer electrolyte membrane fuel cell electrodes fabricated via simultaneous electrospinning/ electrospraying method

摘要

In this study, membrane electrode assemblies (MEAs) were fabricated using a simultaneous electrospinning/electrospraying (E/E) technique to produce a unique nanoparticleanofiber cathode catalyst layer morphology evidenced by scanning electron microscopy. H_2/O_2 and H_2/air polymer electrolyte membrane fuel cell performance was evaluated for E/E MEAs at ultra-low Pt cathode loadings of 0.052 and 0.022 mg_(pt) cm~(-2), where maximum power densities of 1.090 and 0.936 W cm~(-2) (H_2/O_2) and 0.656 and 0.625 W cm~(-2) (H_2/air) were achieved at these two Pt loadings, respectively. This was compared to a conventional control MEA at a 0.42 mg_(pt) cm~(-2) cathode catalyst loading with maximum power densities of 1.420 and 0.839 W cm~(-2) for H_2/O_2 and H_2/air, respectively. These results correspond to a significant reduction in Pt loading (5-12% of control) at only a modest reduction in power density (～66-78% of control) for the E/E electrodes. Excellent platinum utilization in the cathode of 0.024 g_(pt) kW~(-1) (～42 kWg_(pt)~(-1) ) was achieved for the E/E electrode at 0.022 mg_(pt) cm~(-2) cathode loading. Cyclic voltammetry results show an electrochemical surface area higher in the E/E electrodes compared to the control, which provides a rationale for the excellent platinum utilization results, where the E/E morphology results in more triple phase boundaries with more accessible Pt in the electrode.