Enhance performance of micro direct methanol fuel cell by in situ CO2 removal using novel anode flow field with superhydrophobic degassing channels

Abstract Capillary blocking caused by CO 2 bubbles in anode flow field ( AFF ) is one of the bottlenecks for performance improvement of a micro direct methanol fuel cell (μDMFC). In this work, we present a novel AFF structure with nested layout of hydrophilic fuel channels and superhydrophobic degassing channels which can remove most of CO 2 from AFF before it is released to the fuel channels. The new AFFs are fabricated on Ti substrates by using micro photochemical etching combined with anodization and fluorination treatments. Performance of the μDMFCs with and without superhydrophobic degassing channels in their AFF is comparatively studied. Results show that the superhydrophobic degassing channels can significantly speed up the exhaust of CO 2 from the AFF . CO 2 clogging is not observed in the new AFFs even when their comparison AFFs have been seriously blocked by CO 2 slugs under the same operating conditions. 55% and 60% of total CO 2 produced in μDMFCs with N -serpentine and N -spiral AFF can be respectively removed by the superhydrophobic degassing channels. The power densities of the μDMFCs equipped with new serpentine and spiral AFFs are respectively improved by 30% and 90% compared with those using conventional AFFs. This means that the new AFFs developed in this work can effectively prevent CO 2 -induced capillary blocking in the fuel channels, and finally significantly improve the performance of the μDMFCs.