Optimized microporous layer for improving polymer exchange membrane fuel cell performance using orthogonal test design

Abstract

The microporous layer of gas diffusion layer plays an important role in water management of polymer exchange membrane fuel cells. Many factors affect the performance of the microporous layer, and these factors are interrelated. In this work, the orthogonal test method is used to study the effects of four factors including hydrophobic agent, the ratio of carbon powder to hydrophobic agent, carbon powder and microporous layer loading. Nine experiments with four factors and three levels are carried out. The effects of these different factors on the microporous layer are studied. The polarization curves and electrochemical impedance spectroscopy of fuel cells are tested and the scanning electron microscopy, contact angle and pore size distribution of MPL are characterized to prove that the conclusions obtained by orthogonal tests are correct and reliable. It is observed that carbon powder, hydrophobic agent and microporous layer loading have significant effects on the performance of fuel cell than that of the ratio of carbon powder to hydrophobic agent. These three factors mainly influence the cells performance by affecting the ohmic resistance and mass transfer resistance. This work provides a reference for the rapid optimization of microporous layer composition and hence improve the water management of the fuel cell.