Mass transport in anode gas diffusion layer of direct methanol fuel cell derived from compression effect
Mass transport in anode gas diffusion layer of direct methanol fuel cell derived from compression effect
复制标题
直接甲醇燃料电池阳极气体扩散层中源自压缩效应的传质
DOI：
10.1016/j.jpowsour.2019.04.058
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发表时间：
2019-07-01
影响因子：
9.2
通讯作者：
Xing, Wei
中科院分区：
文献类型：
--
作者：
Deng, Guangrong;Liang, Liang;Xing, Wei
阳极气体扩散层对传质起着重要作用。通过调节组装压力，可以控制气体扩散层的结构，以研究两相行为。电化学测试表明，增加组装压力导致传质阻力增加。利用三维成像技术观察了气体扩散层的不均匀压缩。根据实验数据，建立了两相模型。模拟结果表明，由于气体扩散层的压缩，表面粗糙度的增加和孔隙率的降低加剧了CO2对电池的堵塞。降低阳极气体扩散层中聚四氟乙烯含量，可以通过减小液固、气固界面的表面张力差和气体扩散层的负毛细压力来缓解CO2堵塞。因此，在1.00和2.00 MPa的组装压力下，峰值功率密度分别从60.61 - 49.94 mW cm（-2）攀升至74.79和70.47 mW cm（-2）。最佳的组装压力位于膜电极组件和双极板之间实现良好接触的位置，其中气体扩散层变形可能最小。
The anode gas diffusion layer plays an important role on mass transport. By adjusting the assembly pressure, the structure of gas diffusion layer can be controlled to investigate the two-phase behavior. The electrochemical test indicates that increasing the assembly pressure causes increase in mass transport resistance. Inhomogeneous compression of gas diffusion layer is observed by three-dimensional imaging technology. Based on the experimental data, a two-phase model is established. The simulated results show that the increment of surface roughness and the reduction of porosity, both derived from compression of gas diffusion layer, exacerbate CO2 blockage of the cell. Lowering polytetrafluoroethylene content of anode gas diffusion layer alleviates CO2 blockage by reducing the difference of surface tension between liquid-solid and gas-solid interface as well as the negative capillary pressure of gas diffusion layer. Thus, the peak power density climbs from 60.61 to 49.94 mW cm(-2) to 74.79 and 70.47 mW cm(-2) at the assembly pressure of 1.00 and 2.00 MPa, respectively. The optimal assembly pressure locates at where good contact between membrane electrode assembly and bipolar plate is achieved, with the least gas diffusion layer deformation possible.