Investigation of a High-Performance Nanofiber Cathode with Ultralow Platinum Loading for Proton Exchange Membrane Fuel Cells

摘要

Nanofiber electrodes fabricated by using the electrospinning technique in the cathode of proton exchange membrane fuel cells gave a peak power density of 0.692Wcm(-2) with an ultralow Pt loading of 0.087mgcm(-2). As the cathode, the electrospun (E_spun) electrodes exposed a high Pt surface to oxygen, with a highly uniform distribution of Pt catalyst and Nafion ionomer, which improved the utilization of Pt. The ionic resistance of the E_spun electrode was decreased owing to the nanofiber structure. The high porosity of the E_spun electrode enhanced the Knudsen diffusion in small pores, which mitigated the oxygen-transfer resistance. The addition of 5wt polytetrafluoroethylene (PTFE) to the E_spun electrode optimized water management, especially at high current densities. The accelerated stability test showed that the long-term durability of the E_spun electrode is much better than the conventional decal electrode due to the interaction of the carbon support and hydrophilic poly(acrylic acid).