Affiliation:
1. Tongji University, School of Automotive Studies
Abstract
<div class="section abstract"><div class="htmlview paragraph">Proton exchange membrane fuel cell (PEMFC) is a promising energy supply device.
Its improvement on output performance has always been a main subject.
Microporous layer (MPL) is the water management center of PEMFC, which has an
important influence on the mass transfer process and performance of PEMFC under
high current density. In this paper, the performance of GDL based on Toray-H-060
with different carbon powder and C:PTFE of MPL were tested and optimized. SEM
and static contact Angle was used to investigate Characterization of GDLs. The
polarization curve was used to select the best performance, and EIS was used to
explore the internal optimization mechanism. The output performance increases
with humidity from 25%RH to 75%RH for all four samples. The MPL sample
formulated with C: PTFE = 8:2 and XC-72 powder is the best under wide humidity
region, and the best performance is achieved at 75%RH. The maximum power density
reaches 0.949W/cm<sup>2</sup> at 1.8A/cm<sup>2</sup>. At 100%RH, because of
dense structure, the GDL of Toray substrate has poor output performance and low
maximum power density of PEMFC, because of cathode flooding under high humidity
conditions. The increasement of MPL hydrophobicity, achieved by change of carbon
powder and PTFE content, contributes to the decrement of mass transfer
resistance at high current density. The equilibrium between proton conductivity
and water management is essential to ensure improved fuel cell performance. In
summary, this study is useful for understanding influence of MPL contents on
mass transfer performance in PEMFC and can guide the composition design of
MPL.</div></div>