质子交换膜燃料电池阴极有序催化层数学模拟

Numerical simulation of ordered catalyst layer in cathode of proton exchange membrane fuel cells

建立了质子交换膜燃料电池阴极有序催化层的二维数学模型以分析影响性能的主要因素并优化结构参数.模型方程涉及质子、电子传导,气体扩散和电化学反应等过程,并以有限元法求解.计算结果表明,阴极有序催化层通过降低传质阻力而显著提高了电化学性能;影响传递性能的主要因素是O2通过电解质膜的扩散,电子和质子传导以及O2的气相扩散作用不大;降低碳载体和气孔直径、增加催化层厚度主要通过增加催化剂载量改善催化层性能,而减小电解质膜厚度可以促进O2扩散而提高催化层性能.

A steady, two -dimensional numerical model was presented in order to analyze and optimize the performance of an ordered cathode catalyst layer in Proton Exchange Membrane Fuel Cells. The model equations, which account for the electron and proton transport, the oxygen diffusion in the gas pores and the electrolyte phase and the electrochemical reaction kinetics, were solved by the finite element method. The simulation results revealed that the ordered catalyst layer performance was greatly increased by improving various transport processes. It was also found that the key obstacle to mass transport was oxygen diffusion in the electrolyte, whereas electron and proton transport, oxygen diffusion in gas pores imposed no substantial impacts. The performance enhancement by decreasing the diameters of carbon supports and gas pores, or increasing the catalyst layer thickness was mainly ascribed to the higher catalyst loadings. The electrolyte film thickness played an important role in improving the performance of the ordered cathode catalyst layer.