Sulfophenylated centimeter-sized graphene membrane in a direct methanol fuel cell

作者：Weizhe Zhang, Max Makurat, Xue Liu, Buhang Chen, Yanglizhi Li, Xiaoting Liu, Thomas Kock, Andy Jiao, Guangya Jiang, Christopher Leist, Clément Maheu, Hikmet Sezen, Dario Calvani, Ismail Eren, Lin Jiang, Francesco Buda, Haoyuan Qi, Jan P. Hofmann, Xinliang Feng, Ute Kaiser, Luzhao Sun, Zhongfan Liu, Agnieszka Kuc, Thomas Heine, Grégory F. Schneider · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-65507-3 · 被引用次数：2 · 研究领域：Fuel Cells and Related Materials、Electrocatalysts for Energy Conversion、Nanopore and Nanochannel Transport Studies

An ideal proton exchange membrane should only allow protons to pass and remain impermeable to fuels, as required in fuel cell applications. In methanol fuel cells, high proton conductivity enables high power density, whereas methanol crossover between the electrodes degrades the catalyst activity and lowers efficiency. In conventional polymer membranes, however, conductivity and selectivity are often antagonistic: long transport pathways are needed to achieve selectivity, but these introduce additional ionic resistance. Graphene, a two-dimensional material consisting of a single atomic layer of carbon, intrinsically addresses both requirements. Its basal plane is impermeable to water and other molecules, while still exhibiting a measurable degree of proton conductivity. Here, we show that chemical functionalization of monolayer graphene with sulfophenyl groups significantly enhances its proton transport properties. The conductance increases from 6.9 ± 1.1 to 30.9 ± 2.3 S·cm-2, while the energy barrier for proton transport is reduced to 6.9 kJ·mol-1. These findings propose functionalized graphene as an alternative to polymer membranes for electrochemical energy devices. Single-layer graphene, owing to its impermeability, is a promising candidate to prevent transmembrane ion transport. Here, the authors report a covalent functionalization method that enables centimeter-sized graphene to function as a proton exchange membrane in a direct methanol fuel cell.