阳极和阴极流场组合对直接甲醇燃料电池性能的影响

Effect of anode and cathode flow fields on performance of direct methanol fuel cell

采用蛇形、平行和交指流场分别作为阳极和阴极流场,考察了其对直接甲醇燃料电池(DMFC)性能的影响。结果表明,对于阳极流场,蛇形流场因其更易于排除CO2气泡而性能最好,而平行和交指流场中则出现了CO2气泡堵塞流道的现象,影响了甲醇的传输,性能较差。对于阴极流场,平行流场下半部分流道出现了'水淹'现象,影响了氧气的传输,性能较差。蛇形和交指流场均能顺利排除水滴,性能比平行流场的好;交指流场能保证氧气的充足供应,高电流密度时比蛇形流场的电池性能好。蛇形流场作为阳极流场以及交指流场作为阴极流场将是电池性能较好的流场组合形式之一。

The effect of anode and cathode flow fields on the performance of a direct methanol fuel cell（DMFC）was experimentally investigated.Serpentine flow field（SFF）,parallel flow field（PFF）and interdigitated flow field（IFF）were designed,fabricated and tested.The studies were conducted in a DMFC with an active membrane area of 25 cm2,working at ambient temperature,using two kinds of methanol concentration solution（1 mol·L-1 and 2 mol·L-1）,of methanol flow rates（2.1 ml·min-1and 7 ml·min-1）and of oxygen flow rates（100 ml·min-1and 300 ml·min-1）.The results show that SFF as anode flow field has a positive effect on cell voltage and power as better removal of CO2 bubbles.It is also found that CO2 bubbles block flow channels in both PFF and IFF at high current densities,which leads to worse cell performance.For cathode flow field,it is found that water drops block flow channels in PFF,but this channel-blocking phenomenon is never found in both SFF and IFF.The DMFC equipped with both SFF and IFF yields much better performance than that with PFF.The IFF can enhance oxygen transport and cells gain better performance than that with SFF at high current densities.So,it could be deduced that SFF as anode flow field and IFF as cathode flow field would be one of the best choice for the DMFC.