Achieving high Pt utilization and superior performance of high temperature polymer electrolyte membrane fuel cell by employing low-Pt-content catalyst and microporous layer free electrode design

Abstract

Reducing the platinum (Pt) use is of significance to popularize high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) since its average Pt loading in a typical gas diffusion electrode (GDE) normally reaches 0.7 mg cm−2. In this work, an attempt to lower the Pt loading for the electrodes of HT-PEMFC is made by employing low-Pt-content catalysts (20 wt% and 10 wt% Pt/C) with the combination of microporous layer (MPL)-free electrode structure design, by which high Pt utilization and minimum ohmic/mass transfer resistances can be simultaneously maintained. Voltage loss mechanism and the catalyst layer (CL) morphologies of the GDEs are analyzed by polarization curve, electrochemistry impedance spectroscopy, cyclic voltammetry and scanning electron microscopy. The results show that the electrode Pt loading can be lowered to 0.2 mg cm−2 by this strategy but it still demonstrates a maximum Pt-specific performance of 1.6 W mgPt−1 and an area-specific power density of 0.32 W cm−2, which is a considerable improvement on developing HT-PEMFC with low Pt loading. There is a tradeoff between reducing Pt loading and increasing Pt utilization to maintain a superior CL quality, then ensuring that the fuel cell performance is fit for practical applications.