Experimental Studies of Graphene-Coated Polymer Electrolyte Membranes for Direct Methanol Fuel Cells

Nathan Metzger, Ivan Vlassiouk, Sergei Smirnov, Gabriel Mariscal, Ryan Spragg, Xianglin Li

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The two main technical limitations of direct methanol fuel cells (DMFCs) are the slow kinetic reactions of the methanol oxidation reaction (MOR) in the anode and the crossing over of unreacted methanol through the proton exchange membrane (PEM). It is a common practice to use Nafion membranes as PEMs, which have high ion exchange capacity. However, Nafion-based membranes also have high fuel permeability, decreasing fuel utilization, and reducing the potential power density. This article focuses on using graphene-coated (Gr-coated) PEMs to reduce fuel crossover. Protons can permeate across graphene, and thus, it can be employed in various devices as a proton conductive membrane. Here, we report the efficiency of Gr-coated Nafions. We tested performance and crossover at three different temperatures with four different fuel concentrations and compared it to a Nafion PEM that underwent the same test conditions. We found that the adhesion of Gr on to PEMs is insufficient for prolonging fuel cell operation, resulting in Gr delamination at high temperatures and higher fuel crossover values compared to lower temperature testing. The results for 7.5M methanol fuel show a reduction of up to 25% in methanol crossover, translating to a peak power density that increases from 3.9 to 9.5 mW/cm2 when using a Gr-coated PEM compared to a Nafion PEM at 30 °C.

Original languageEnglish
Article number020903
JournalJournal of Electrochemical Energy Conversion and Storage
Volume20
Issue number2
DOIs
StatePublished - May 2023

Funding

This material is based on work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Hydrogen and Fuel Cell Technologies Office, Award Number DE-EE0008440. This work was partially supported by a grant from the Department of Energy (ARPA-E DE-AR0000651). A portion of this project involving the graphene membrane fabrication and characterization was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

FundersFunder number
U.S. Department of Energy
Office of Science
Advanced Research Projects Agency - EnergyDE-AR0000651
Office of Energy Efficiency and Renewable Energy
Hydrogen and Fuel Cell Technologies OfficeDE-EE0008440

    Keywords

    • DMFC
    • Nafion
    • PEM
    • fuel management
    • graphene
    • methanol crossover

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