Abstract
Proton exchange membrane fuel cells (PEMFCs) typically use Nafion®, which has many drawbacks, such as high cost, fuel crossover, and strenuous synthesis processes. As such, an alternative Nafion®-ionomer free proton conductor has drawn significant interest. Graphene oxide membrane (GOM) is a promising alternative due to its hydrophilic nature and attractive proton conductivity under humidified conditions. However, pristine GOMs have drawbacks, including fuel crossover, a high reduction rate of negatively oxygenated functional groups during fuel cell operation, and proton conductivity showing excessive orientation dependence. We focused on nanocomposite-GOM (N-GOM) based on PFSAs, hydrocarbon polymers, synthetic polymers, inorganic-organic polymers, biopolymers, metal-organic frameworks, and micro- and nano-engineered surfaces. GO nanosheets have outstanding dispersion rate and compatibility with ionomer matrices that can be functionalized by sulfonation, polymerization, phosphorylation, cross-linking, incorporated inorganic nanoparticles, and blending with matrix, microscale-nanoscale fabrication. The N-GOM exhibits high-performance fuel cells with improved proton conductivity, physicochemical properties, and low fuel crossover compared to Nafion®. For instance, SCSP/SF membranes with 3% functionalized GO (FGO) content displayed the highest conductivity of 26.90 mS cm−1and the best selectivity (methanol) of 4.10 × 105S cm−3at room temperature. Moreover, a new scalable, efficient chitosan (CA)-based composite membrane (CA/GO) was fabricated. In addition, surface-patterned nanostructures in thin films increased the PEMFC output power to 950 mW cm−2, higher than 590 mW cm−2for non-patterned Nafion®. Finally, we report on the optimal composition ratio for each material of the N-GOM-based membrane. This review discusses the most crucial developments in proton conductivity and outlines the current progress for the N-GOM as a revolutionary form of PEM. The general objective of this research is to review all possible modifications of N-GOM from the perspective of their practical application as electrolytes in fuel cells.
Funder
National Research Foundation of Korea
Publisher
The Electrochemical Society
Subject
Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials
Cited by
6 articles.
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