The impact of graphene-based materials on anion-exchange membrane fuel cells

This study addresses the challenges of power output and durability in anion-exchange membrane (AEM) fuel cells (AEMFCs) through the use of graphene-based materials. Graphene oxide (GO) and partially reduced graphene oxide (prGO) with varying degrees of reduction were synthesized and characterized via Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). AEMs were coated with the synthesized graphene materials and tested with Pt catalyst. The addition of GO and prGO with high degrees of reduction improved power output by 12 % and 5 %, respectively, and increased durability by 29 %. Optimal reduction degree of prGO showed significant improvements, enhancing power output by 53 % and doubling membrane life. When FeCo-N-C replaced Pt/C at the cathode, the power enhancement with intermediate prGO was reduced to 16 %, and durability increased by only 13 %, indicating a specific synergy with Pt. X-ray computed tomography (XCT) analysis showed that graphene addition maintained membrane integrity and prevented Pt nucleation within the membrane. However, after 140 h, the membrane interface became rough, causing electrical shorts. It is hypothesized that the hexagonal carbon ring structure of graphene allows OH⁻ migration but blocks larger Pt ions, preventing degradation. Further investigation is needed to understand the significant power enhancement with minimal prGO addition.