Authors: Tamar Zelovich, Leslie Vogt-Maranto, Cataldo Simari, Isabella Nicotera, Michael A. Hickner, Stephen J. Paddison, Chulsung Bae, Dario R. Dekel, and Mark E. Tuckerman
Recent studies suggest that operating anion exchange membrane (AEM) fuel cells at high temperatures has enormous technological potential. However, obtaining a fundamental understanding of the effect of temperature on hydroxide conductivity and membrane stability remains a key hurdle to realizing the full potential of high-temperature AEM fuel cells. In this work, we present a combined theoretical and experimental study to explore the effect of temperature on hydroxide ion and water diffusivities in AEMs. Both fully atomistic ab
Authors: Saja Haj-Bsoul, John R. Varcoe, Dario R. Dekel
One significant barrier in developing durable, robust anion-exchange membranes (AEMs) for liquid-electrolyte-free fuel cells (AEMFCs) and water electrolyzers (AEMWEs) is their limited chemical stability to alkali. To measure the alkaline stability of AEMs, ex-situ tests are commonly used where the AEMs are immersed for long durations in aqueous alkali solutions. However, such tests do not adequately simulate the liquid-electrolyte-free environment of AEMFCs and AEMWEs, as the hydration and alkaline conditions do not always mimic actual operando conditions, yielding misleading and inaccurate indications of degradation rates for relatively low hydration conditions. We recently reported a unique ex-situ method which
Authors: Karam Yassin, Igal G. Rasin, Simon Brandon, Dario R. Dekel
The anion-exchange ionomer (AEI) is a crucial component of anion-exchange membrane fuel cells (AEMFCs). In this study, computational analysis is employed to study the unexplored and critical effect of AEI hydroxide conductivity, within the cathode electrode, on AEMFC performance and its stability. The cathode is of particular importance due to its tendency to dry-out in a manner that may impact ionomer conductivity during AEMFC operation. Our modeling results clearly show that enhanced AEI hydroxide conductivity, within the cathode, significantly increases AEMFC performance. Less intuitive is its positive impact on cell stability. Superior conductivity
Authors: Hamish A. Miller, Marco Bellini, Dario R. Dekel, Francesco Vizza
In 2016, for the first time a polymer electrolyte fuel cell free of Pt electrocatalysts was shown to deliver more than 0.5 W cm−2 of peak power density from H2 and air (CO2 free). This was achieved with a silver-based oxygen reduction (ORR) cathode and a Pd-CeO2 hydrogen oxidation reaction (HOR) anodic electrocatalyst. The poor kinetics of the HOR under alkaline conditions is a considerable challenge to Anion Exchange Membrane Fuel Cell (AEMFC) development as high Pt loadings are still required to achieve reasonable performance. Previously, the ameliorative combination of Pd and CeO2 nanocomposites has been exploited
Authors: Kanika Aggarwal, Saja Bsoul, John C. Douglin, Songlin Li, Dario R. Dekel, Charles E. Diesendruck
Anion-exchange membrane fuel cells (AEMFCs) are promising energy conversion devices due to their high efficiency. Nonetheless, AEMFC operation time is currently limited by the low chemical stability of their polymeric anion-exchange membranes. In recent years, metallopolymers, where the metal centers assume the ion transport function, have been proposed as a chemically stable alternative. Here we present a systematic study using a polymer backbone with side-chain N-heterocyclic carbene (NHC) ligands complexed to various metals with low oxophilicity, such as copper, zinc, nickel, and gold. The golden
Authors: Cataldo Simari, Ernestino Lufrano, Muhammad Habib Ur Rehmana, Avital Zhegur-Khais, Saja Haj-Bsoul, Dario R. Dekel, Isabella Nicotera
We report on an extensive study on nanocomposite Anion Exchange Membranes (AEMs) based on tetramethylammonium Polysulfone ionomer and Layered Double Hydroxide (LDH) as nanofiller. The AEMs were investigated in both OH− and HCO3− forms, comparing swelling capacity and transport properties. Ionic conductivity measurements were performed both by Electrochemical Impedance Spectroscopy and Ziv and Dekel's method, while the water and ions mobility by H Pulse Field Gradient (PFG) NMR spectroscopy.
One of the most serious problems to be addressed in AEMs fuel cell technology is that of the significant loss of performance when CO2 is present in the reaction oxidant gas (e.g., air) due to the
Authors: Ana Laura G. Biancolli, Saja Bsoul-Haj, John C. Douglin, Andrey S. Barbosa, Rog´erio R. de Sousa Jr., Orlando Rodrigues Jr., Alexandre J.C. Lanfredi, Dario R. Dekel, Elisabete I. Santiago
Anion-exchange membrane fuel cells (AEMFCs) are rapidly gaining visibility in the clean energy research field due to their high power output and potential to significantly reduce materials costs. However, despite the high performances obtained, in-operando stability still presents a major obstacle for this technology. The durability issues are usually attributed to the core component of the AEMFCs - the anion-exchange membrane (AEM). An easy and simple way to produce these AEMs is through
Authors: Yifan Li, Dario R. Dekel, and Ofer Manor
We demonstrate the application of a 20 MHz frequency surface acoustic wave (SAW) in a solid substrate to render its surface “self-cleaning”, redirecting the deposition of precipitating mass onto a nearby inert substrate. In our experiment, we confine a solution of poly(methyl methacrylate) polymer and a volatile toluene solvent between two substrates, lithium niobate and glass, at close proximity. We render the glass surface low energy by employing hydrophobic coating. In the absence of SAW excitation, we observe that the evaporation of the solvent yields polymer coating on the higher energy lithium
Authors: Horie Adabi, Pietro Giovanni Santori, Abolfazl Shakouri, Xiong Peng, Karam Yassin, Igal G. Rasin, Simon Brandon, Dario R. Dekel, Noor Ul Hassan, Moulay-Tahar Sougrati, Andrea Zitolo, John R. Varcoe, John R. Regalbuto, Frederic Jaouen, William E. Mustain
One of the most important needs for the future of low-cost fuel cells is the development of highly active platinum group metal (PGM)-free catalysts. For the oxygen reduction reaction, Fe–N–C materials have been widely studied in both acid and alkaline media. However, reported catalysts in the literature show quite different intrinsic activity and in-cell performance, despite similar synthesis routes and precursors. Here, two types of Fe–N–C are prepared from
Authors: Yogesh Kumar, Elo Kibena-Põldsepp, Jekaterina Kozlova, Mihkel Rähn, Alexey Treshchalov, Arvo Kikas, Vambola Kisand, Jaan Aruväli, Aile Tamm, John C. Douglin, Scott J. Folkman, Ilario Gelmetti, Felipe A. Garcés-Pineda, José Ramón Galán-Mascarós, Dario R. Dekel, and Kaido Tammeveski
Non-precious-metal catalysts are promising alternatives for Pt-based cathode materials in low-temperature fuel cells, which is of great environmental importance. Here, we have investigated the bifunctional electrocatalytic activity toward the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of mixed metal (FeNi; FeMn; FeCo) phthalocyanine-modified multiwalled carbon nanotubes (MWCNTs) prepared by a simple pyrolysis method. Among the bimetallic catalysts containing nitrogen
