The study on dynamic response performance of PEMFC with RuO_2·xH_2O/CNTs and Pt/C composite electrode

摘要

Dynamic response performance of Proton Exchange Membrane (PEM) fuel cells affects its durability and reliability significantly. In this study, in order to promote the PEM fuel cell dynamic response performance, RuO_2·xH_2O/CNTs was prepared by sol-gel method and then sprayed onto the Pt/C electrode surface to form the cathode. The RuO_2·xH_2O/CNTs prepared was characterized by Transmission Electron Microscopy (TEM), which shows the average particle size of RuO_2·xH_2O is 3 nm and particulates are well distributed. Performance of single cells with and without RuO_2·xH_2O/CNTs at the cathode under various operating conditions such as different gases pressure, air stoichiometry and relative humidity was studied using cyclic voltammetry, electrochemical impedance spectra (EIS) and polarization curve techniques. When the fuel cell modified with RuO_2·xH_2O/CNTs was operated at lower pressure and higher air stoichiomotery, a faster and more stable dynamic response could be found. It was also found that the humidity of cathode inlet gas had a significant effect on fuel cell performance. Adding 0.1 mg/cm~2 RuO_2·xH_2O/CNTs (RuO_2·xH_2O 11%) composite material not only slightly increases the single cell performance but also dramatically improves the dynamic response performance, revealing that RuO_2·xH_2O/CNTs can buffer the voltage undershoot whenever the current increases instantly.