Article
Electrochemistry
Yongzhen Qi, Jiangjin Liu, Dinesh C. Sabarirajan, Ying Huang, Andrea Perego, Andrew T. Haug, Iryna V. Zenyuk
Summary: Effective ionic conductivity of pseudo catalyst layers (PCLs) was measured using electrochemical impedance spectroscopy (EIS) across a range of relative humidity (RH) and found to be higher than results obtained using the hydrogen pump (HP) method. This discrepancy is attributed to the difference in counting ionic pathways in the two methods. Additionally, high surface area carbon support resulted in lower effective ionic conductivity due to poor ionomer dispersion, and possible carbon agglomeration within PCLs led to lower ionic conductivity compared to Pt/C layers.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Electrochemistry
M. Barreiros Salvado, P. Schott, L. Guetaz, M. Gerard, Y. Bultel
Summary: Through the combination of multiscale modeling and electron microscopy characterization, the study quantifies and discusses the effects of structural parameters such as Pt particle size, agglomerate structure, and Nafion layer thickness on the performance of PEMFCs. The analysis reveals the main mechanisms limiting performance at moderate/high current densities and allows to quantify and rank the physical phenomena hampering performance by order of importance.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Electrochemistry
W. Olbrich, T. Kadyk, U. Sauter, M. Eikerling
Summary: This study presents a structure-based model that predicts wetting phenomena inside the cathode catalyst layer of polymer electrolyte fuel cells, thus achieving optimal water management. Compared to existing modeling approaches, this model provides a more accurate description of wetting behavior and can be used for fuel cell design and optimization.
ELECTROCHIMICA ACTA
(2022)
Article
Energy & Fuels
Omer Sahin, Abdurrahman Akdag, Sabit Horoz, Arzu Ekinci
Summary: PdNix and PdNiZr bimetallic catalysts supported by Vulcan XC-72 R were synthesized using NaBH4 and formic acid as reduction agents. Structural and morphological properties of these nanocatalysts were evaluated using XRD, SEM, and TEM analysis. XPS analysis confirmed successful incorporation of Pd, Ni, Zr, and C elements in the structure of Pd/C, PdNi/C, and PdNiZr/C catalysts. EDX analysis determined the weight percentages of metals in these catalysts. Electrochemical properties, activity, and stability, including electrochemically active surface area, were examined using various techniques. Polarization curves showed that PdNiZr/C and PdNi/C catalysts outperformed Pd/C catalyst. At 70 degrees C, power densities of Pd/C, PdNi/C, and PdNiZr/C catalysts were measured as 27.54 mWcm(-2), 114 mWcm(-2), and 188 mWcm(-2), respectively.
Article
Chemistry, Physical
Seyma Kil, Oguz Kaan Ozdemir, Mert Akin Insel, Hasan Sadikoglu
Summary: Fuel cell systems are environmentally friendly energy converters, but face challenges in commercialization due to high catalyst costs and water management issues.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Shaojun Dou, Liang Hao, Hong Liu
Summary: This study presents a pore-scale simulation of water capillary condensation in the cathode catalyst layer of proton exchange membrane fuel cells and investigates the effects of porosity and wettability on water distribution, gas transport, and proton conduction.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
Yue Wan, Diankai Qiu, Peiyun Yi, Linfa Peng, Xinmin Lai
Summary: The design of a gradient catalyst layer, with different wetting properties on each sub-layer, significantly enhances the performance of a proton exchange membrane fuel cell. The gradient layer improves the mass transfer capacity and power density of the fuel cell, resulting in higher efficiency.
Article
Chemistry, Physical
Xiang Lyu, Tim Van Cleve, Erica Young, Jianlin Li, Haoran Yu, David A. Cullen, K. C. Neyerlin, Alexey Serov
Summary: Proton exchange membrane fuel cells (PEMFCs) powered by green hydrogen (H2) are a promising alternative to traditional hydrocarbon-fueled power generators. However, further improvements are needed in efficiency, durability, and low-cost production for widespread adoption. Most strategies to improve PEMFC electrodes utilize single material sets, but anisotropic electrode structures with locally tunable properties may offer enhanced performance due to improved transport.
JOURNAL OF POWER SOURCES
(2023)
Review
Thermodynamics
Klaere Christmann, K. Andreas Friedrich, Nada Zamel
Summary: This review focuses on the activation process in polymer electrolyte membrane fuel cells and the mechanisms behind performance improvement during initial operation. It was found that the main mechanisms during activation include removal of solvents from production and changes in the catalyst layer ionomer and membrane surface.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2021)
Article
Electrochemistry
Anne-Christine Scherzer, Patrick Schneider, Patrick K. Herring, Matthias Klingele, Nada Zamel, Dietmar Gerteisen
Summary: We propose a model that can simulate the morphology of the cathode catalyst layer before and after loading with Pt and ionomer. The model accurately describes the size distributions of support nanopores and catalyst particles, allowing for qualitative predictions during the addition of materials. The model focuses on the impregnation and blockage of pores due to ionomer loading and its consequences on the Pt/ionomer interface, ionomer film thickness, and protonic binding. It successfully emulates different catalyst/support combinations and explains the non-monotonic increase of protonically active catalyst surface area with ionomer addition in some supports.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Thermodynamics
Pascal Ruzzante, Xianguo Li
Summary: Proton exchange membrane fuel cells have potential in achieving global net-zero emissions. The efficiency loss of the catalyst layer, attributed to transport resistance and reaction mechanisms in its porous structure, needs to be studied using a computational reconstruction model. A hybrid stochastic reconstruction technique is compared to conventional methods, using pore size distributions, surface area, porosity, mean pore diameter, and mean chord lengths to evaluate accuracy. Method 2 achieves higher accuracy in mean chord lengths and surface area compared to Methods 1 and 0, while both Methods 1 and 2 improve mean pore size over Method 0.
Article
Electrochemistry
Michael Moore, Shantanu Shukla, Stephan Voss, Kunal Karan, Adam Weber, Iryna Zenyuk, Marc Secanell
Summary: The study presents a single-phase model for proton exchange membrane fuel cells, involving hydrogen transport, hydrogen oxidation reaction, and oxygen reduction reaction. Experimental results demonstrate that the model can effectively predict changes in OCV with varying platinum loading and fuel cell performance. At low platinum loadings, unreacted hydrogen escapes due to oxide blocking and anion adsorption, highlighting the kinetic limitations of the hydrogen oxidation reaction.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Review
Chemistry, Physical
Xiaohui Yan, Zhiling Xu, Shu Yuan, Aidi Han, Yuanting Shen, Xiaojing Cheng, Yuwei Liang, Shuiyun Shen, Junliang Zhang
Summary: This review summarizes the importance of PFSA ionomer in proton exchange membrane fuel cells (PEMFCs) and its influence on fuel cell performance. By comparing the properties of PFSA bulk membrane and ultrathin ionomer film, as well as the microstructure and proton conduction behavior of the ionomer in the catalyst layer, the impact mechanism of the ionomer on fuel cell performance is revealed. Modifying the chemical structure of the ionomer and engineering the interaction between the ionomer and catalyst hold promise for greatly improving the performance of ultra-low platinum loading PEMFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Physical
M. Barreiros Salvado, P. Schott, L. Guetaz, M. Gerard, T. David, Y. Bultel
Summary: The research team proposed a framework for cathode catalyst layer design that combines electron microscopy characterization and numerical modeling software. They found that structural heterogeneities can deeply impact performance, mainly due to oxygen diffusion limitations and interparticle competition effects.
JOURNAL OF POWER SOURCES
(2021)
Article
Chemistry, Physical
Yuan Gao, Weixiong Qu, Rui Zhu
Summary: This study investigates the reconstruction and optimization methods of the catalyst layer in proton exchange membrane fuel cells, with results showing that a process-based reconstruction method is superior to traditional models, and optimal structural parameters for CL's best output performance are proposed. This has significant reference value for understanding and optimizing the structural characteristics of the CL.
JOURNAL OF POWER SOURCES
(2021)
Article
Electrochemistry
Andrei Kulikovsky
Summary: The impedance of oxygen transport in two porous layers A and B positioned between the air channel and cathode catalyst layer in a PEM fuel cell cannot be separated into individual layer impedances. The two-layer system functions as a unified oxygen transport media.
ELECTROCHEMISTRY COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Andrei Kulikovsky
Summary: The impedance spectra of a commercial PEMFC stack were analyzed using a physics-based model and distribution of relaxation times (DRT) techniques. The oxygen transport coefficients of different layers were determined at various current densities. The results from the fitted model and the DRT technique showed good agreement.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Biochemistry & Molecular Biology
Tatyana V. Reshetenko, Andrei Kulikovsky
Summary: This study presents a model for local impedance of low-Pt proton exchange membrane fuel cells, which was successfully applied to determine the O-2 transport resistivity. The results show that the operating current density does not significantly affect the O-2 transport resistivity RN.
Article
Energy & Fuels
Andrei Kulikovsky
Summary: The study introduces a new method for calculating distribution of relaxation times (DRT) in PEM fuel cells, which performs better in capturing the negative real part of impedance. By utilizing this method, successful analysis of DRT spectra in PEMFCs has been achieved, accurately capturing peaks related to oxygen transport and proton transport.
FRONTIERS IN ENERGY RESEARCH
(2021)
Correction
Electrochemistry
A. Kulikovsky
ELECTROCHIMICA ACTA
(2022)
Article
Electrochemistry
Andrei Kulikovsky
Summary: This passage discusses the analytical solution for impedance modeling of a PEM fuel cell cathode, which can be applied to low current densities and sufficient oxygen conditions. Experimental spectra can quickly fit parameters of the oxygen reduction reaction, and can be used in standard spectra fitting software.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Biochemistry & Molecular Biology
Andrei Kulikovsky
Summary: In this study, a model for concentration/pressure impedance zeta of the cathode catalyst layer of a low-Pt PEM fuel cell is developed. The model is based on transient oxygen mass transport equations through a single pore with a thin Nafion film covering. An analytical solution for zeta-impedance at high cell current is derived for fast fitting of experimental data. This technique is a useful alternative to standard EIS.
Article
Electrochemistry
Andrei Kulikovsky
Summary: A model for PEMFC cathode impedance is developed, and the transient response of catalyst layer proton conductivity to cell current density variation is analyzed. The results show that this transient conductivity leads to the formation of a low-frequency inductive loop in the Nyquist spectrum.
ELECTROCHEMISTRY COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Ying Sun, Thomas Kadyk, Andrei Kulikovsky, Michael Eikerling
Summary: A dynamic model for the concentration admittance of a polymer electrolyte fuel cell is presented in this paper. The model considers oxygen transport and derives an analytical solution. The admittance at the air channel outlet can be used to extract oxygen transport coefficients.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Tatyana Reshetenko, Madeleine Odgaard, Guenter Randolf, Kenta K. Ohtaki, John P. Bradley, Barr Zulevi, Xiang Lyu, David A. Cullen, Charl J. Jafta, Alexey Serov, Andrei Kulikovsky
Summary: In this study, a cathodic catalysts layer (CCL) design was achieved using a catalyst coated membrane approach with Platinum Group Metal-free (PGM-free) electrocatalysts. Three different Fe-Mn-N-C compounds were synthesized and characterized, and their electrochemical properties were evaluated. It was found that the CCLs exhibited high proton conductivity and predominantly exhibited a 4e- oxygen reduction reaction mechanism.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Electrochemistry
Andrei Kulikovsky
Summary: This study uses a recent analytical model to analyze the impedance of PEM fuel cells. The results show that the resistivity of the peaks is affected by variations in oxygen transport parameters.
ELECTROCHIMICA ACTA
(2022)
Editorial Material
Electrochemistry
Andrei Kulikovsky
Summary: Pressure perturbation applied at the cathode channel of a PEM fuel cell leads to oscillating cell potential and current. Experimental spectra reported so far have shown that the measured voltage response under fixed total current is generally not reproducible, possibly due to random fluctuations of local current.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Tatyana Reshetenko, Andrei Kulikovsky
Summary: A model that considers the pore size distribution in the cathode catalyst layer of PEM fuel cell is developed. The model approximates the experimental pore size distribution by three different pore sizes (small, medium, and large) and assigns separate oxygen diffusion coefficients for each pore. The model is fitted to experimental impedance spectra of a low-Pt PEM fuel cell. The results show that oxygen reduction mainly occurs in the small and medium pores, while the large pores only contribute to mass transport. This finding explains the discrepancy between the effective oxygen diffusivity measured in situ by limiting current method and the larger value determined from ex situ experiments using Loschmidt cell.
MATERIALS RESEARCH EXPRESS
(2023)
Article
Electrochemistry
Andrei Kulikovsky
Summary: This paper extends Berman's model for the laminar flow of incompressible fluid in a channel with permeable walls to consider variable velocity of injection along the channel. The system of two-dimensional continuity and Navier-Stokes equations is simplified to a single ODE for the transversal velocity with coefficients dependent on the position along the channel. A numerical solution for the flow in the cathode channel of a PEM fuel cell is presented. The flow velocity profile across the channel is almost indistinguishable from the Poiseuille's parabolic shape, but the distribution of pressure gradient and longitudinal velocity differ significantly from Berman's result.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Andrei Kulikovsky
Summary: This article derives a formula for the concentration (zeta-) impedance of reactant transport through a finite-length layer attached to an electrochemical electrode. The static point of the Nyquist spectrum is independent of the layer transport parameters, while the peak of I zeta is located at a frequency close to the Warburg finite-length frequency.
RESULTS IN CHEMISTRY
(2022)
