Article
Chemistry, Physical
Soonyong So, Keun-Hwan Oh
Summary: In this study, catalyst ink was prepared using a dispersant with an HLB value of 17. The effects of ionomer-catalyst agglomerate size on ink rheological properties, CL microstructure, and electrochemical performance were investigated. The results showed that the smallest agglomerate size and low PDI were obtained with 1 wt% dispersant content, resulting in well-dispersed ink. The MEA based on the 1 wt% CL exhibited the highest performance due to increased number of channels and back pressure.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Yu-Tong Mu, Pu He, Fan Bai, Li Chen, Zhi-Guo Qu, Wen-Quan Tao
Summary: Characterizing oxygen transport resistances in different components of a polymer electrolyte membrane fuel cell (PEMFC) is essential for achieving better cell performance. The proposed macroscopic three-dimensional model and agglomerate model help analyze the impacts of operating conditions on these resistances. The study provides insights into the structure-dependent local transport resistance in the electrode and the contributions of different cell components to the total transport resistance. Understanding and optimizing oxygen transport in PEMFCs are crucial for improving their efficiency and performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Hao Yuan, Haifeng Dai, Pingwen Ming, Sida Li, Xuezhe Wei
Summary: This paper proposes a two-dimensional multiphase PEM fuel cell impedance model coupled with an improved electrochemical kinetics model, which can reproduce the measured electrochemical impedance spectroscopy (EIS) under different conditions. The effects of five CCL design parameters on the EIS and critical internal dynamics are comprehensively investigated, offering a deeper understanding of the parameters' impact on PEM fuel cell performance.
Article
Chemistry, Physical
Jinhyuk Lim, Jung Woo Shim, Dong Joon Kim, Jong Seon Park, Junmo Koo, Joon Hyung Shim
Summary: The study demonstrates that coating a zirconia protective layer on the platinum catalyst through atomic layer deposition (ALD) can enhance the performance of polymer electrolyte membrane fuel cells. The analysis shows that even a few ALD cycles can effectively suppress catalyst aggregation and decrease deterioration rate, leading to improved stability and performance of the fuel cell catalysts.
JOURNAL OF POWER SOURCES
(2021)
Article
Energy & Fuels
Takahiro Saida, Kan Sakakibara, Ryohei Igami, Takahiro Maruyama
Summary: This study investigates the use of carbon spheres as a catalyst support in polymer electrolyte fuel cells. The carbon spheres promote diffusion and improve platinum utilization by supporting highly dispersed platinum nanoparticles. The study finds that the platinum utilization rate and oxygen reduction reaction activity are enhanced with the use of carbon spheres as the catalyst support.
Article
Electrochemistry
Fengmin Du, Tuan Anh Dao, Andreas Bauer, Michael Obermaier, Thomas J. Schmidt, Alin Orfanidi
Summary: This study aims to understand the relationship between carbon corrosion and performance degradation in polymer electrolyte membrane fuel cells. A simplified model is developed to simulate the performance changes during carbon corrosion. The results show that the model accurately describes the voltage losses at different stages of corrosion and reveals the adverse effects of characterization tests on electrochemical active surface area.
ELECTROCHIMICA ACTA
(2022)
Article
Electrochemistry
Nancy N. Kariuki, Andrew T. Haug, Jae H. Park, Matthew J. Lindell, Deborah J. Myers
Summary: Ultra-small angle X-ray scattering technique was used to investigate the effects of carbon support type, presence of platinum, and ionomer loading on the microstructure of polymer electrolyte fuel cell catalyst layers. It was found that carbon type, platinum presence, and ionomer loading significantly impact carbon agglomeration, which in turn affects electrode performance.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Toru Uenishi, Rui Imoto
Summary: To optimize the cathode catalyst layer of MEAs for polymer electrolyte fuel cells, a data-driven model was developed using the physical properties of the catalyst layer to predict performance. Automated feature extraction through image processing and measurement data from electron microscopy images and XRD eliminated variation due to differences among analysts. A sensitivity analysis using the data-driven model revealed that diffusion in the interparticle voids and intra-particle diffusion of carbon aggregates were the key factors for performance improvement.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Jonathan P. Braaten, Nancy N. Kariuki, Deborah J. Myers, Scott Blackburn, Gerald Brown, Andrew Park, Shawn Litster
Summary: This study focuses on the integration of a high oxygen permeability ionomer with high durability carbon supported platinum catalysts for the preparation of cathode catalyst layers in PEMFCs. The results show that this integration leads to significant improvements in specific activities at low current densities and reduced oxygen transport resistances at high current densities. This integration has the potential to enhance the efficiency and peak power density of PEMFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Nanoscience & Nanotechnology
Junmo Koo, Heon Jun Jeong, Wonjoon Choi, Joon Hyung Shim
Summary: Platinum-carbon nanotube (CNT) catalysts were evaluated as cathode catalysts for polymer electrolyte membrane fuel cells. Pt catalysts were fabricated using atomic layer deposition on bare or O2 plasma treated CNTs. The morphology of the Pt particles differed on the two types of CNT supports, leading to differences in electrochemical and fuel cell performance. Factors other than geometric features also influenced fuel cell performance.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Masashi Harada, Hiroaki Kadoura, Shin-ichi Takata, Hiroki Iwase, Shuji Kajiya, Takahisa Suzuki, Naoki Hasegawa, Akihiro Shinohara, Satoru Kato
Summary: The performance of a polymer electrolyte fuel cell can be enhanced by improving the proton conductivity of the catalyst layer, which is influenced by both ionomer content and carbon support. A novel proton conductivity model is introduced to simulate catalyst layers with different amounts of ionomers and carbon types. The model considers the presence of thin-film ionomers with suppressed proton conductivities and suggests that reducing the fraction of thin-film ionomers or avoiding factors that suppress their proton conduction improves the performance of the catalyst layer.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Electrochemistry
Arturo Sanchez-Ramos, Jeff T. Gostick, Pablo A. Garcia-Salaberri
Summary: Under low Pt loading, maximizing the maximum power density can be achieved by using relatively thin catalyst layers with high carbon volume fraction. Under high Pt loading, higher porosity and pore radius are beneficial despite thicker ionomer films.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Nanoscience & Nanotechnology
Mohamed R. Berber, Muhammad Imran, Hanako Nishino, Hiroyuki Uchida
Summary: The addition of hygroscopic silica nanoparticles to the Pt/C anode catalyst layer can greatly prolong the lifetime of a Nafion membrane in the accelerated stress test and improve the output performance at low relative humidity. It can also decrease the formation rate of H2O2 and reduce the ohmic resistance, leading to effective utilization of Pt cathode catalyst. These findings provide a rational explanation for the enhancement of PEM durability and output performance.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Kanji Otsuji, Naoki Yokota, Donald A. Tryk, Katsuyoshi Kakinuma, Kenji Miyatake, Makoto Uchida
Summary: Research focuses on water management challenges and improvements in cell performance for anion exchange membrane fuel cells (AEMFCs) using a non-PGM catalyst and an in-house-developed anion exchange ionomer. Results show that water plays a critical role in the cathode reaction and that the hysteresis effect is related to water supply to the cathode using the Fe-N-C catalyst. Managing water is essential for high-performance AEMFCs.
JOURNAL OF POWER SOURCES
(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
Thermodynamics
Mustafa Ercelik, Mohammed S. Ismail, Derek B. Ingham, Kevin J. Hughes, Lin Ma, Mohamed Pourkashanian
Summary: Nickel foams are excellent candidate materials for gas diffusion layers in polymer electrolyte fuel cells due to their superior structural and transport properties. A computational framework has been developed to estimate these properties and investigate their uniformity and isotropy.
Article
Engineering, Chemical
Guojun Zhang, Lin Ma, Mohamed Pourkashanian
Summary: Rotating packed bed (RPB) technology has great potential for post-combustion capture. However, simulating the capture process inside the full RPB is difficult due to complexity and neglect of CO2 capture in the outer cavity zone. A full 3D CFD model, including packing and inner and outer cavity zones, was established in this study. The CO2 capture performance in the packing and outer cavity zones was quantitatively analyzed under different conditions. The simulation results showed good agreement with experimental data, and the contribution of the outer cavity zone to the CO2 capture of the RPB ranged from 28% to 42%. This work provides a new approach for efficient simulation of mass transfer in RPB.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Energy & Fuels
Isaac C. Okereke, Mohammed S. Ismail, Derek B. Ingham, Kevin Hughes, Lin Ma, Mohamed Pourkashanian
Summary: A new three-dimensional numerical model was developed to investigate the impact of double-sided microporous layer (MPL) coating on the performance of a polymer electrolyte fuel cell (PEFC). The results showed that the MPL coating significantly improved the fuel cell performance by up to 30%. Neglecting the contact resistance between the MPL and the catalyst layer could overestimate the fuel cell performance by up to 6%. The porosity of the MPL facing the bipolar plate had a greater influence on the fuel cell performance and current and oxygen distribution than the porosity facing the catalyst layer. All the results are presented and discussed in detail.
Article
Energy & Fuels
James M. Harman-Thomas, Touqeer Anwar Kashif, Kevin J. Hughes, Mohamed Pourkashanian, Aamir Farooq
Summary: Experimental data on ignition delay times (IDTs) of syngas in CO2 diluted conditions were obtained. It was found that the reaction of CO2 and H to form CO and OH caused the separation of H2 and CO ignition, increasing the complexity of determining the IDTs. A method to determine simulated IDTs was proposed for effective comparison with experimental data.
Article
Thermodynamics
Jinbei Tian, Mohammed S. Ismail, Derek Ingham, Kevin J. Hughes, Lin Ma, Mohamed Pourkashanian
Summary: This study investigates the impact of three different flow channel cross sections on fuel cell performance. The results show that the novel hybrid configuration with a square cross section at the inlet and trapezoidal cross section at the outlet has a slight performance gain due to increased velocity, improving reactant gas supply, heat dissipation, and excess water removal. Reducing the outlet height of the hybrid configuration further enhances fuel cell performance.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Engineering, Mechanical
Yunus Celik, Derek Ingham, Lin Ma, Mohamed Pourkashanian
Summary: The study introduces a new hybrid blade design for the Darrieus vertical axis wind turbine, combining a conventional airfoil with a J-shaped profile to enhance torque generation during start-up and mitigate efficiency loss at higher tip speed ratios. A 2D-based design methodology is proposed, and through it, different hybrid blade configurations are investigated for overall and self-starting performance. A 3D CFD dynamic start-up model is built to evaluate performance and the results show that the proposed design methodology enables quicker prediction of aerodynamic performance compared to 3D-based CFD simulations. Additionally, the new hybrid blade designs not only resolve self-starting issues but also improve turbine operating range and peak efficiency.
JOURNAL OF FLUIDS AND STRUCTURES
(2023)
Article
Engineering, Chemical
Davide Poggio, Arman Sastraatmaja, Mark Walker, Stavros Michailos, William Nimmo, Mohamed Pourkashanian
Summary: In-situ biomethanation combines conventional biogas production with the addition of hydrogen to produce higher quality biomethane gas. The study investigates the effects of various factors, such as biogas recirculation rate and stirring intensity, on the performance of in-situ biomethanation using sewage sludge and food waste. The results indicate that the rate-limiting factor is H-2 gas-liquid mass transfer, and improving this factor is crucial for achieving desired biogas quality.
Article
Energy & Fuels
Narvin D. Neehall, Mohammed S. Ismail, Kevin J. Hughes, Mohamed Pourkashanian
Summary: The through-plane gas permeability and morphology of PEFC gas diffusion media (GDM) were investigated for different microporous layer (MPL) ink homogenisation techniques (bath sonication and magnetic stirring) for low- (Vulcan XC-72R) and high- (Ketjenblack EC-300J) surface-area carbon powders. The results showed that magnetic stirring doubled the through-plane gas permeability of GDM compared to bath sonication for MPLs composed of Vulcan XC-72R, while there was negligible change in surface morphology. For MPLs composed of Ketjenblack EC-300J, the through-plane gas permeability varied almost negligibly, but the MPL surface morphology changed considerably with bath sonication, leading to smoother, less cracked surfaces compared to magnetic stirring.
Article
Thermodynamics
Maria Fernanda Rojas-Michaga, Stavros Michailos, Evelyn Cardozo, Muhammad Akram, Kevin J. Hughes, Derek Ingham, Mohamed Pourkashanian
Summary: This research evaluates the technical, economic, and environmental performance of a Power-to-Liquid (PtL) system for sustainable aviation fuel (SAF) production. The system includes a direct air capture unit, an offshore wind farm, an alkaline electrolyser, and a refinery plant. The results show high carbon conversion efficiency but intensive electricity requirements. The well-to-wake life cycle assessment reveals that the SAF's global warming potential falls below the emissions reduction target compared to fossil jet fuel.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Energy & Fuels
Karim Rabea, Stavros Michailos, Godfrey T. Udeh, Jiseon Park, YongWoon Lee, Seongil Kim, Won Yang, Kevin J. Hughes, Lin Ma, Mohamed Pourkashanian
Summary: This study presents a new hybrid renewable energy system for a smart farm in South Korea, which includes solar PV arrays, heat pumps, thermal energy storage tanks, and a wood pellet boiler. The system is economically feasible and significantly reduces CO2 emissions.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2023)
Review
Green & Sustainable Science & Technology
Fatma Calili-Cankir, Mohammed S. Ismail, Derek B. Ingham, Kevin J. Hughes, Lin Ma, Mohamed Pourkashanian
Summary: This review focuses on improving the performance of air-breathing polymer electrolyte fuel cells by optimizing key parameters such as the design and material of the current collector, cathode gas diffusion layer, catalyst layer, and cell orientation. It also discusses the impact of ambient conditions on fuel cell performance and methods to mitigate extreme temperature and humidity effects. Additionally, it summarizes hydrogen storage and delivery technologies used in these fuel cells and critiques their design aspects. The review concludes by highlighting the challenges to widespread commercialization of air-breathing fuel cell technology by examining reported fuel cell stacks and systems.
Article
Green & Sustainable Science & Technology
Ava Shahrokhi, Julien Berthaut-Gerentes, Lin Ma, Derek Ingham, Mohamed Pourkashanian
Summary: This paper validates the effectiveness and accuracy of using a reduced turbulence integral length scale for inflow generation in large eddy simulation (LES) and develops a technique to estimate the real local length scales using simulation results. The results show that there is an excellent agreement between the length scale from simulation and measurement when scaled with their corresponding freestream/inlet value. This indicates that a reduced integral length scale can be safely used for LES to provide reliable predictions for energy spectrum and length scales around complex geometries.
Article
Energy & Fuels
Charlie Adams, Ehsan Alborzi, Xue Yong, Simon Blakey, Anthony J. H. M. Meijer, Mohamed Pourkashanian
Summary: A combination of experimental and quantum chemical techniques confirmed the theory that sulfur acids are the initial species to deposit on stainless steel.