Renewable Energy Global Innovations features: Polydopamine as a promising candidate for the design of high performance and corrosion-tolerant polymer electrolyte fuel cell electrodes

Significance Statement

Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are considered to have potential as clean energy converters for future applications. There are huge cost considerations due to the usage of noble metal Pt which hinders its commercialization. To reduce the amount of Pt loading, Carbon with Pt nanoparticles is used but under harsh conditions in the PEMFC electrode, carbon materials and nanotubes degrade.

Researchers led by Dr. Marc Michel at Luxembourg Institute of Science and Technology used electrode structure made up of polydopamine (PDA) and carbon nanotubes in PEMFCs to enable the electrode to withstand the operating conditions arising in the fuel cell. The study is now published in Journal of Power Sources.

Polydopamine, among other advantages, is quite beneficial due to the presence of catechol and amino groups which leads to strong binding between PDA and Pt precursor. It promotes the conductivity of protons. Carbon nanotubes enhance the contact between the catalyst and the electrolyte as they form interconnected conducting networks. Thus, a structure having carbon nanotubes with Pt nanoparticles and coated with polydopamine was chosen for the research. This structure would save the carbon material from oxidation which occurs under the extreme operating conditions of the system.

The scientists prepared a new electrocatalytic active (Pt/MWNTs-PDA)₅₀ multi layered nanocomposite film with spray deposition which is much faster (100 times) than the conventional layer by layer (LBL) assembly. Two catalysts supports were prepared, one having multiwalled carbon nanotubes with Pt nanoparticles but without polydopamine as a reference, and the other wrapped with PDA. Physical characterisations were carried out using various methods (XPS, SEM, etc.) to realize the specifications for the experiment. The results yielded by the characterization showed the PDA covering of 19 %.

In their adsorption/desorption study of the catalyst in hydrogen and oxygen it was observed that the coating of PDA to the catalyst doesn’t affect the catalytic reactions. By Cyclic Voltammetry, the Electrochemical Charged Surface Area (ECSA) for Pt/MWNTs-PDA was found to be 15.2 m²/g(Pt) and for Pt/MWNTs was 10.3m²/g(Pt) for the first cycle. In subsequent cycles, the ECSA for the former was stable and degraded for the latter.

The polarization curves obtained show that the Pt/MWNTs-PDA has a lower open circuit voltage (OCV) than Pt/MWNTs. It is believed by the scientist that OCV will further decrease if PDA content is increased but it is yet to be experimentally confirmed. The concentration losses, on the other hand, shown by Pt/MWNTs-PDA are at higher current densities than that of Pt/MWNTs where the concentration losses start at an earlier current density of 1200 mA/cm². The concentration loss zones of the former are observed to be unstable at high current densities. The scientists infer that the instability might be due to some change in cathode structure.

The stability of the two catalyst supports were compared by continued cyclic voltammogram test. The conductivity of PDA-MWNTs was shown to be stable even after many cycles of operation as the surface resistance did not change. Also, the integral area of cyclic voltammograms for PDA-MWNTs did not change implying a good electrochemical stability. It was also observed, with the normalized plots, that the MWNTs would tend to corrode, and in comparison, PDA-MWNTs do not tend to corrode easily as they have the ability to decrease the overpotential of oxidation.

The research team was able to show that PDA-MWNTs are resistant to oxidation, and show a higher Pt Utilization of 6051 mW/mg which is three times as high as utilization obtained by MWNTs of the same Pt loading. PDA-MWNTs also show better performance based on the power densities observed. For the first time, they showed that polydopamine protects the electrode from corrosion of carbon.

To learn more about the research (EnergyCell)

 

About The Author

Dr. Marc Michel has a PhD in physical chemistry and physics from the University of Strasbourg (University Louis Pasteur, 2005). After his PhD work, Marc won the prestigious Fulbright fellowship in 2005 allowing him to work as visiting researcher at the University of Michigan in the group of Prof. Nick Kotov (Department of Chemical Engineering, Ann Arbor, USA). Between 2007-2008 he worked as researcher at the Technical University of Darmstadt in Germany (Department of Renewable Energies). Since 2008, Dr Michel works as senior scientist in the Materials Research and Technology Department of Advanced in The Luxembourg Institute of Science and Technology (LIST).

Dr. Michel’s research is focused on nanotechnologies, surface science, physical chemistry and in particular on the design of new architectures for renewable energies (EnergyCell Project funded by the Fond National de la Recherche Luxembourg). Dr. Michel has published more than 35 papers in his field of research.

About The Author

Joffrey Didierjean received his master’s degree in materials science from the École Européenne d’Ingénieurs en Génie des Matériaux (Nancy – France) in 2008. He firstly worked as an expert in surface and interface science at the Centre de Recherche Public Gabriel Lippmann in Luxembourg, where he was in charge of studies and analytical methods development on advanced characterization techniques. Since 2015, Joffrey Didierjean has been working in Dr. Michel’s team as research and technology engineer in the Material Science and Technology Department at the Luxembourg Institute of Science and Technology (LIST).

His field of competence covers surface science, nanomaterials and nanotechnologies and supramolecular assembly for the design of controlled architecture in the frame of renewable energy.

About The Author

Hongtao Long completed his Bachelor’s studies at University of Sciences and technologies of Taiyuan (China) in 2010, then he graduated from University of Lorraine (France) in 2013, and he is doing his Ph.D now at the Luxembourg Institute of Science and Technology (List), He started research on “Design of new generation of high performance electrodes for polymer exchange membrane fuel cells made of polyelectrolytes and nanoparticles complexes” with Professor Marc Michel in 2014.

He is interested in carbon materials, conducting polymer and their energy applications. He published “Polydopamine as a promising candidate for the design of high performance and corrosion-tolerant polymer electrolyte fuel cell electrodes” on Journal of power source in 2015.

About The Author

Doriane Del Frari joined the LIST (ex-CRP Henri Tudor) in 2007. From 2002 to 2005, she prepared her PhD in chemistry in the Laboratoire d’Electrochimie des Matériaux (Metz, France). Her PhD deals with the realization of thermoelectric materials by electrodeposition, for applications related to their properties, which lie mainly in the field of the heat transfer.

From 2006 to 2007, she worked at the Commissariat à l’Energie Atomique (Saclay, France) on an in situ AFM study of localized corrosion of stainless steel. Since 2007, she was in charge of the corrosion characterization of aluzinc samples (TRASU project) and electrochemical characterization domain of the materials unit.

She is currently in charge of electrical and electrochemical characterization at the Central Lab of the MRT department (Luxembourg Institut of Science and Technology).

 

Journal Reference

Hongtao Long³, Doriane Del Frari³, Arnaud Martin³, Joffrey Didierjean³, Vincent Ball^1,2, Marc Michel³, Hicham Ibn El Ahrach³. Polydopamine as a promising candidate for the design of high performance and corrosion-tolerant polymer electrolyte fuel cell electrodes. Journal of Power Sources, pp. 569-577, 2016.

Show Affiliations

¹ Unité INSERM 1121, Faculté de médecine, 11 rue Humann, 67085 Strasbourg Cedex, France

² Université de Strasbourg, Faculté de Chirurgie Dentaire, 8 rue Sainte Elisabeth, 67000 Strasbourg, France

³ Luxembourg Institute of Science and Technology (LIST), Materials and Research Technology (MRT), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg

 

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