1. Graphene coating of Nafion$^{(R)}$ membranes for enhanced fuel cell performance
- Author
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Ruhkopf, Jasper, Plachetka, Ulrich, Moeller, Michael, Pasdag, Oliver, Radev, Ivan, Peinecke, Volker, Hepp, Marco, Wiktor, Christian, Lohe, Martin R., Feng, Xinliang, Butz, Benjamin, and Lemme, Max C.
- Subjects
Physics - Applied Physics - Abstract
Electrochemically exfoliated graphene (e-G) thin films on Nafion$^{(R)}$ membranes exhibit a selective barrier effect against undesirable fuel crossover. The approach combines the high proton conductivity of state-of-the-art Nafion$^{(R)}$ and the ability of e-G layers to effectively block the transport of methanol and hydrogen. Nafion$^{(R)}$ membranes are coated with aqueous dispersions of e-G on the anode side, making use of a facile and scalable spray process. Scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) confirm the formation of a dense percolated graphene flake network which acts as diffusion barrier. The maximum power density in direct methanol fuel cell (DMFC) operation with e-G coated Nafion$^{(R)}$ N115 is 3.9 times higher than the Nafion$^{(R)}$ N115 reference (39 vs. 10 mW cm$^{-2}$ @ 0.3 V) at 5M methanol feed concentration. This suggests the application of e-G coated Nafion$^{(R)}$ membranes for portable DMFCs, where the use of highly concentrated methanol is desirable.
- Published
- 2022
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