Platinum loading and electrolyte volume fraction simultaneous gradient distributions in a proton exchange membrane fuel cell: Improving electrical performance and mass transfer

Abstract

Platinum loading and electrolyte content affect the surface area of electrochemical reaction and proton conductivity, respectively, and protons and oxygen are not uniformly distributed in the catalyst layer. Therefore, platinum loading and electrolyte content can be set to be simultaneous non-uniform distributions to further enhance the species utilization and cell performance. In this study, a non-isothermal, two-dimensional, two-phase fuel cell model is set up and coupled with the catalyst layer agglomerate model. The electrolyte content and platinum loading uneven distributions influence on products and reactants transmission and electrical property is explored. Results indicate that electrolyte volume fraction and platinum loading coinstantaneous graded distribution is more helpful in the species transfer and electrical property improvement. The maximum power density of coinstantaneous graded distribution of platinum content and electrolyte loading along the channel direction is increased by 3.40% compared with the uniform distribution, and is 2.94% higher than the superposition of the maximum power density when the graded distributions of electrolyte volume fraction and platinum loading are separately set. Moreover, the platinum content and electrolyte content gradient distributions do not make liquid water saturation present an evident segment variation along the channel direction, while the opposite is true for oxygen concentration.