Authors: Karam Yassin, John C. Douglin, Igal G. Rasin, Pietro G. Santori, Bjorn Eriksson, Nicolas Bibent, Fr´ed´eric Jaouen, Simon Brandon, Dario R. Dekel
We present a comprehensive theoretical and experimental study of the effect of membrane thickness on the anion-exchange membrane (AEM) fuel cell (AEMFC) performance. AEMFC tests are carried out with several AEMs with thickness in the range of 5 – 50 µm and assembled with a PtRu anode, and two different cathode catalysts (Pt/C or FeNC). Dramatic improvements in cell performance are observed as the membrane thickness decreases, which is mainly attributed to reduced ohmic losses and enhanced water transport between
Authors: Maria V. Pagliaro, Cuilian Wen, Baisheng Sa, Baoyu Liu, Marco Bellini, Francesco Bartoli, Sanjubala Sahoo, Ramesh K. Singh, S. Pamir Alpay, Hamish A. Miller, Dario R. Dekel
Anion-exchange membrane fuel cells (AEMFCs) are a promising electrochemical power generation technology that will most likely find applications in stationary power supply and mobile applications such as electric vehicles in the future. One of the main technological challenges with AEMFCs is developing catalysts with improved activities to reduce the current overpotential losses in the cell. A historically underappreciated challenge for AEMFC catalyst development is the sluggish hydrogen oxidation reaction (HOR) kinetics at the
Authors: John C. Douglin, Ramesh K. Singh, Eliran R. Hamo, Mohamad B. Hassine, Paulo J. Ferreira, Brian A. Rosen, Hamish A. Miller, Gadi Rothenberg, Dario R. Dekel
This study focuses on H2-O2 operando AEMFC performance based on several platinum group metal (PGM) and PGM-free catalysts. Specifically, we evaluate the AEMFC performance of commercial PtRu/C, as-synthesized PtRu/C, and Pd-CeO2/C catalysts as anodes and commercial Pt/C and as-synthesized N-doped carbon catalysts as cathodes. The evolution of cell performance with varying cathode catalyst layer compositions, back pressure, and dew points is underscored. The as-synthesized PtRu/C catalyst is characterized by advanced transmission electron microscopy and showed significantly
Authors: Kanika Aggarwal, Songlin Li, Elisa Ivry, Dario R. Dekel, and Charles E. Diesendruck
Metallopolymers are intriguing prospective materials for use as anion exchange membranes (AEMs) in fuel cells and water electrolysis applications. Metallopolymers potentially offer high ion conductivity due to the multivalent nature of metal cations; however, similar to organic cations, the durability of the organic component can be compromised by the alkaline environment. To develop AEMs with long operational lifetimes, the fundamental relationship between the metal–ligand pair and alkaline stability needs to be understood. Here, we synthesize metallopolymers with different N-heterocyclic carbene ligand side chains that are connected to
Authors: Marian Chatenet, Bruno G. Pollet, Dario R. Dekel, Fabio Dionigi, Jonathan Deseure, Pierre Millet, Richard D. Braatz, Martin Z. Bazant, Michael Eikerling, Iain Staffell, Paul Balcombe, Yang Shao-Horn and Helmut Schafer
Replacing fossil fuels with energy sources and carriers that are sustainable, environmentally benign, and affordable is amongst the most pressing challenges for future socio-economic development. To that goal, hydrogen is presumed to be the most promising energy carrier. Electrocatalytic water splitting, if driven by green electricity, would provide hydrogen with minimal CO2 footprint. The viability of water electrolysis still hinges on the availability of durable earth-abundant electrocatalyst materials and the
Authors: Zi-Ye Xiao, Charles E. Diesendruck, Viatcheslav Freger, and Dario R. Dekel
We successfully electropolymerize homopolymer and copolymer from vinylbenzyltrimethylammonium chloride (VBTMA) and divinylbenzene (DVB) by cyclic voltammetry to form ultra-thin anion-conducting polymer films with significant anion conductance. The morphologies of electropolymerized polymers with different monomer compositions are analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In-situ electrochemical impedance spectroscopy (in situ EIS) is performed to track the electropolymerization (EP) process and film properties. High anion conductance of up to 2 mS is found in the electropolymerized thin films, suggesting that this technique can be suitable for making anion-conducting
Authors: Tamar Zelovich, Cataldo Simari, Isabella Nicotera, Dario R. Dekel and Mark E. Tuckerman
Exposing anion exchange membrane (AEM) fuel cells to ambient air is known to decrease fuel cell efficiency significantly due to the presence of CO2. In this combined theoretical and experimental study, we examine the hydration conditions that promote reactions between CO2 and hydroxide ions in nano-confined AEMs, and we explore the effect of the carbonation process on the solvation structure and diffusion of hydroxide ions. Using fully atomistic ab initio molecular dynamics (AIMD) simulations, we find that increasing hydration can delay the carbonation reaction between OH− and CO2. Once reacted, HCO3− ions
Authors: Julian Lorenz, Holger Janßen, Karam Yassin, Janine Leppin, Young-Woo Choi, Jung-Eun Cha, Michael Wark, Simon Brandon, Dario R. Dekel, Corinna Harms, and Alexander Dyck
Although substantial improvement of the performance of anion exchange membrane fuel cells (AEMFCs) was achieved, longevity is still the main challenge for the AEMFC technology, which is attributed to the degradation of the functional groups of applied membranes and ionomers. Contrary to ex situ material stability studies, we demonstrate here the application of ion chromatography to quantify the amounts of degradation products in the exhaust water during different fuel cell operation conditions on the example of
Authors: Kanika Aggarwal, Nansi Gjineci, Alexander Kaushansky, Saja Bsoul, John C. Douglin, Songlin Li, Ihtasham Salam, Sinai Aharonovich, John R. Varcoe, Dario R. Dekel, and Charles E. Diesendruck
Anion-exchange membrane (AEM) fuel cells (AEMFCs) and water electrolyzers (AEMWEs) have gained strong attention of the scientific community as an alternative to expensive mainstream fuel cell and electrolysis technologies. However, in the high pH environment of the AEMFCs and AEMWEs, especially at low hydration levels, the molecular structure of most anion-conducting polymers breaks down because of the strong reactivity of the hydroxide anions with the quaternary ammonium (QA) cation functional groups that are
Authors: Carlo Santoro, Alessandro Lavacchi, Piercarlo Mustarelli, Vito Di Noto, Lior Elbaz, Dario R. Dekel, and Frédéric Jaouen
As highlighted by the recent roadmaps from the European Union and the United States, water electrolysis is the most valuable high-intensity technology for producing green hydrogen. Currently, two commercial low-temperature water electrolyzer technologies exist: alkaline water electrolyzer (A-WE) and proton-exchange membrane water electrolyzer (PEM-WE). However, both have major drawbacks. A-WE shows low productivity and efficiency, while PEM-WE uses a significant amount of critical raw materials. Lately, the use of anion-exchange membrane water electrolyzers (AEM-WE) has been proposed to overcome the limitations of the
