Performance degradation of a proton exchange membrane fuel cell with dual ejector-based recirculation
Yang Liu, Biao Xiao, Junjie Zhao, Lixin Fan, Xiaobing Luo, Zhengkai Tu, Siew Hwa Chan
Abstract
Effective water management is particularly critical for fuel cells fed by hydrogen/oxygen. An ejector is an optimal device for the gas recirculation subsystem of a proton exchange membrane fuel cell (PEMFC) and is usually adopted for the auxiliary drainage of hydrogen/oxygen stacks. To explore the performance degradation of the fuel cells operating in dual ejector-based recirculation mode for both the anode and cathode, the dynamic characteristics of gas purging of the PEMFC was studied experimentally and the effects of the electrolyte and gas management strategy of the fuel cell on performance degradation were investigated in detail by using the measurement of polarization curves, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM) images of membrane electrode assembly (MEA) cross sections. The results indicated that the fuel cell with Nafion® 212 operating in the dual ejector-based recirculation mode has a better performance than that operating in the dead-ended mode, with total electrochemical surface area (ECSA) degradation rates of 10.61% and 17.02%, respectively. The ejector in the recirculation mode can accelerate the removal of liquid water from the fuel cell flow channel, avoiding water flooding and performance deterioration of fuel cells during long-term operation..