Improving the performance of direct methanol fuel cells using a performance-enhancing layer

• Published in: Fuel (Guildford) 2024-06, Vol.366, p.131366, Article 131366
• Main Authors: Wan, Chieh-Hao, Huang, Yunliang, Leong, Yoong Kit, Gu, Yesong
• Format: Article
• Language: English
• Subjects: Direct methanol fuel cells; Methanol crossover mitigation; PDDA/sPPO; Performance-enhancing layer; Self-assembly layers
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.131366

[Display omitted] •A performance-enhancing layer is used to improve the DMFC’s performance.•This layer is constructed by PDDA/sPPO bi-layers with Pt45-Ru55 deposited on carbon self-assembled on both sides of Nafion.•The MEA with the performance-enhancing layer showed increased power density of 75.1%.•The possible mechanism of performance improvement has been proposed. In this study, a performance-enhancing layer formed by 5 and 10 bi-layers of poly(diallyldimethylammonium chloride) (PDDA) and sulfonated-poly(2,6-dimethyl-1,4-phenylene oxide) (sPPO) loaded with Pt–Ru/C catalyst that self-assembled on both sides of Nafion membrane through the layer-by-layer deposition technique was utilized to improve the performance of direct methanol fuel cells. The membrane electrode assemblies (MEAs) with 5 and 10 PDDA/sPPO bi-layers which loaded with 4.5 and 9.2 μg cm−2 Pt–Ru/C catalyst exhibited increased power densities of 40.9 % and 75.1 % respectively, when compared to MEA with pristine Nafion membrane under 80 °C. The performance improvement was believed to be attributable to the additional electrons and protons produced by oxidization of crossed-over methanol by Pt–Ru/C catalyst at the PDDA/sPPO bi-layers, as well as effective transfer of these electrons and protons to the cathode through the continuous conductive carbon layer with the Nafion proton conductor in the bi-layers. Furthermore, the mixed potential effect at the cathode was reduced by the Pt–Ru/C catalyst consumption and the PDDA/sPPO bi-layer mitigating the crossed-over methanol.