Research Vision and Aims
Our research vision is driven by the growing concerns over climate change, energy independence, energy storage, and the need for mitigating greenhouse gas emissions from automobiles and end-user energy uses. We aim to develop a holistic experimental-numerical approach toward the fundamental understanding of materials-transport-interface interactions in emerging energy technologies that will help us continually improve the performance of emerging energy devices (
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Our research strengths are computational fluid dynamics and heat transfer, experimental characterization, and diagnostics of sustainable energy conversion and storage systems. We are developing fundamental understanding, data-driven techniques, experimental protocols, and remote sensing mechanisms for sustainable energy conversion and storage systems.
Our aims are to address research questions relevant to sustainable energy conversion and storage, including, but not limited to,
- How to minimize thermal degradation during the fast charging of a Li-ion battery?
- What are the trade-offs between performance, battery life, and consumer demand (e.g., charging as quickly as possible) for reducing environmental impact?
- How to generate more power from fuel cells without flooding their electrodes?
- How to improve water and thermal management for hydrogen fuel cells?
- What trade-off should be made between the cost and durability of a fuel cell to compete with internal combustion engine vehicles?
- How to harvest more solar energy or extract more heat from electronic devices?
- What are the health and safety impacts of using second-hand batteries for grid energy storage?
- Can we predict thermal-, vibration- or shock-induced failure early and prevent battery fire?
- L. Xing, Y. Xu, P.K. Das, B. Mao, Q. Xu, H. Su, and W. Shi, Numerical Matching of Anisotropic Transport Processes in Porous Electrodes of Proton Exchange Membrane Fuel Cells, Chemical Engineering Science, 195, 127-140, 2019.
- L. Xing, P.K. Das, K. Scott, and W. Shi, Inhomogeneous Distribution of Platinum and Ionomer in the Porous Cathode to Maximize the Performance of a PEM Fuel Cell, AIChE Journal, 63(11), 4895-4910, 2017.
- L. Xing, P.K. Das, X. Song, M. Mamlouk, and K. Scott, Numerical Analysis of the Optimum Membrane/Ionomer Water Content of PEMFCs: The Interaction of Nafion Ionomer Content and Cathode Relative Humidity, Applied Energy, 138, 242-257, 2015.
- A.Z. Weber, R.L. Borup, R.M. Darling, P.K. Das, T.J. Dursch, W. Gu, D. Harvey, A. Kusoglu, S. Litster, M. Mench, R. Mukundan, J.P. Owejan, J. Pharoah, M. Secanell, I. Zenyuk, A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells, Journal of the Electrochemical Society, 161 (12), F1254-F1299, 2014.
- P.K. Das and A.Z. Weber, Water Management in PEMFC with Ultra-Thin Catalyst-Layers, Proc. of ASME 11th Fuel Cell Science, Engineering and Technology Conference, pp. 1-10, Minneapolis, USA, Jul. 14-19, 2013.
- A.Z. Weber, S. Balasubramanian, and P.K. Das, Proton Exchange Membrane Fuel Cells, in Fuel Cell Engineering, Advances in Chemical Engineering, 41, 65-144, 2012.
- P.K. Das, A.Z. Weber, B. Guido, A. Manak, D. Bittinat, A.M. Herring, and M.J. Ulsh, Rapid Detection of Defects in Fuel-Cell Electrodes using Infrared Reactive-Flow-Through Technique, Journal of Power Sources, 261, 401-411, 2014.
- N.V. Aieta, P.K. Das, A. Perdue, B. Guido, A.M. Herring, A.Z. Weber, and M.J. Ulsh, Applying Infrared Thermography as a Quality-Control Tool for the Rapid Detection of Proton-Exchange-Membrane-Fuel-Cell Catalyst-Layer-Thickness Variations, Journal of Power Sources, 211, 4-11, 2012.
- A.D. Santamaria, P.K. Das, J. MacDonald, and A.Z. Weber, Liquid-Water Interactions with Gas-Diffusion Layers Surfaces, Journal of the Electrochemical Society, 161 (12), F1184-F1193, 2014.
- P.K. Das, A. Grippin, A. Kwong, and A.Z. Weber, Liquid Water-Droplet Adhesion-Force Measurements on Fresh and Aged Fuel-Cell Gas-Diffusion Layers, Journal of the Electrochemical Society, 159 (5), B489-B496, 2012.
- P.K. Das, X. Li, and Z.S. Liu, Effective Transport Coefficients in PEM Fuel-Cell Catalyst and Gas Diffusion Layers: Beyond Bruggeman Approximation, Applied Energy, 87 (9), 2785-2796, 2010.
- K. Ting, A.K. Mozumder, and P.K. Das, Effect of Surface Roughness on Heat Transfer and Entropy Generation of Mixed Convection in Nanofluid, Physics of Fluids, 31 (9), 093602, 2019. [Editor Pick; Featured Article]
- R. Cong, Y. Ozaki, B.S. Machado, and P.K. Das, Constructal Design of a Rectangular Fin in a Mixed Convective Confined Environment, Inventions, 3 (2), 27-47, 2018.
- A. Bejan, Advanced Engineering Thermodynamics (2nd ed.), New York: Wiley, 1997.
- A. Bejan, Constructal Law: Optimization as Design Evolution, Journal of Heat Transfer, 137(6), 061003, 2015.
In the present scenario of a global initiative toward a sustainable energy future, fuel cells are considered as the most promising clean energy-conversion technologies for automotive and small stationary applications. They efficiently convert the chemical energy of a fuel into usable electrical energy through electrochemical reactions. Among the different types, polymer-electrolyte fuel cells (PEFCs) receive the most attention because of their higher electrical efficiency, power density, and durability. In a PEFC, anode, electrolyte (membrane) and cathode are put together in a sandwich structure. To achieve higher output voltages and higher power, single cells are often combined to a large fuel cell stack.
In a PEFC, fuel - typically hydrogen - and oxygen from air are combined electrochemically across a solid polymer membrane generating electricity, water and heat. PEFCs are classified primarily by the transport of ions (either proton or anion), namely proton-exchange-membrane (PEM) fuel cells and anion-exchange-membrane (AEM) fuel cells as illustrated below, each with its own advantages, limitations, and potential applications.
The operation of a PEFC involves a complex overlap of interrelated physicochemical processes, which include electrochemical reactions as well as transport of ions, electrons, energy, and species in gas and liquid phases across a heterogeneous medium. Though PEFCs have shown promising performance improvement in terms of efficiency and durability over the last three decades, the level of robustness required for operation in widely varying conditions, while matching the current power sources in terms of cost, stifles the commercial utilization of PEFCs. Any further improvements could be greatly aided by a better understanding of the complex processes of fuel-cell operation. Only through fundamental modeling based on physical models developed from experimental observations can the processes and operation of a PEFC be truly understood.
Modeling and simulation at the continuum level have been used for years to help interpret and guide experimental investigations and to improve and optimize the design and operation of PEFCs. Recently, we have developed a two-dimensional, multi-physics model with 3M's nano-structured thin film (NSTF) catalyst layers (CLs) to investigate the interaction between the operating conditions and liquid-water transport across critical proton-exchange-membrane fuel cell (PEMFC) domains. Model data show that the performance of a PEMFC with NSTF CLs is sensitive to the operating temperature due to NSTF CL's inherent low water capacity, as the thickness of an NSTF CL is often in the range of 500 nm (shown in the above figure).
Currently at our group, we are investigating the transport phenomena in the porous media of proton-exchange-membrane fuel cell (PEMFCs) and anion-exchange-membrane fuel cells (AEMFCs) to achieve improved performance and design for automotive applications and thus helping to accelerate the commercialization of fuel cells. For our multi-physics models, we have been using commercial CFD software packages, COMSOL and Fluent, for their inherent advantages over open source CFD software packages. Our PhD students are currently developing 2D and 3D a models using Fluent and COMSOL to understand water and thermal transports in AEMFCs.
The following resources provide additional information about our fuel cell modeling activities:
The aim of the ReLiB project is to establish the technological, economic and legal infrastructure to make the recycling of close to 100% of the materials contained in lithium ion batteries from the automotive sector possible. For further details see the project's website.
The aim of this project is to understand the thermal degradation of Li-ion batteries using a synergistic combination of physics-based modeling and experimental characterization. This project is part of the ReLiB project. For further details of ReLiB project see the project's website.
As fuel cell and fuel-cell-battery (FCB) hybrid systems become more prominent, new manufacturing and production methods are needed to enable increased volumes with high quality. One necessary component of this industrial growth will be accurately predicting defects in membrane-electrode-assembly (MEA) components of FCB systems during the manufacturing process. Defects in MEA components differ in type and extent depending on the fabrication process used. The effects of these defects also differ, depending on size, location in the cell relative to the reactant flow-field, cell operating conditions, and which component contains the defect. Understanding the effects of these different kinds of defects is necessary in order to specify and/or develop diagnostic systems with the accuracy and data acquisition/processing rates required for the speed and size scales of high-volume continuous manufacturing methods. Further, predictive capabilities for manufacturers are critical to assist in the development of tolerances and to enable assessment of the effects of material and process changes.
The use of Infrared (IR) thermography to detect defects in fuel cell MEA components and to quantify the variations in platinum-containing catalyst-layer thickness has shown a great promise for quality assessment. We have developed a reactive-flow-through (RFT) technique and a DC electronic excitation method. The RFT technique involves the flow of a dilute non-flammable H2/O2 gas-mixture through the GDE where the reaction occurs at the Pt catalytic sites in the CL and produces heat (shown above). The DC excitation method involves applying a DC voltage across a catalyst layer and measuring the thermal response using IR thermography (shown below).
Both of these methods invariably involve designing non-destructive experiments, developing diagnostic tools/sensors, and finding the detection criteria that will enable engineers to detect and quantify mechanical defects during the manufacturing process, such as defect size, shape, and location. Currently, we are utilizing our expertise to develop high-fidelity modeling tools for defect detection using IR thermography, which will play an important role in designing and guiding experiments, finding detection criteria, and providing guidance scale-up of the system.
The following resources provide additional information about our defect detection research activities:
Complex multi-phase and porous media play an important role in many clean energy systems, including fuel cells, redox flow batteries, Li-ion batteries, and solar fuel generators. These multi-phase porous media are often sandwiched together in these systems and they must allow ingress of the reactant gasses and egress of the product (either liquid or gas). Describing the multiphase transport aspects of these materials has proven particularly challenging. Mathematical models have been developed for these materials but they must rely on the accurate estimation of the effective physicochemical properties including effective gas-phase diffusivities, absolute and relative permeabilities, water-droplet adhesion force, capillary properties, and thermal and electrical conductivities. These properties are needed to enhance the fundamental understanding of chemical, physical, and transport phenomena within the porous transport media. In-situ measurement of these physicochemical properties is difficult due to the complex assembly of fuel cells and flow batteries, and lack of technological advancement for in-situ measurement.
Over the past years, we have developed several techniques for measuring physicochemical properties of fuel cell and flow battery materials, including adhesion force, capillary properties, and thermal and electrical conductivities. For instance, we have utilized the contact and sliding angles for measuring directly the adhesion force of liquid-water droplets on a proton-exchange-membrane fuel-cell gas-diffusion layer (GDL). The experimental measurement of contact and sliding angles has been performed using a rotating-stage goniometer with a 2-way injection system (as shown above). In this set-up, liquid-water droplets on GDL surface can be placed using either a top placement or a bottom injection method. Once a droplet is placed on the GDL surface, the entire stage is inclined at a constant speed until the droplet completely rolled-off from the GDL surface. The adhesion force between a droplet and GDL surface is then calculated from a measured sliding angle, droplet volume, wetted diameter, and contact angle data using a force balance (as shown below).
Currently, we are working on to develop a combined experimental-numerical approach to measuring effective properties in complex geometries that are relevant to electrochemical and solar thermal systems (such as porous transport layers, insulators, radiant absorbers, heat exchangers, and catalyst carriers). We aim to use X-ray tomography and small-angle X-ray scattering for the morphological characterization of complex multiphase and porous media and for determining their morphological properties such as porosity, specific surface area, and pore-size distribution. The morphological data will then be used to simulate transport processes to determine in-situ effective transport properties.
The following resources provide additional information about our research activities:
Convective heat transfer inside cavities, such as triangular, trapezoidal, cylindrical, square, and wavy, has been extensively analyzed for thermal enhancement and optimization due to their application in many engineering problems such as solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. Due to the equipment miniaturization trend, easily noticed in electronic devices, enhancing or optimizing heat transfer inside cavities is now becoming extremely challenging. To overcome this challenge, researchers proposed the addition of different types of the fin in the cavity and filled with nanofluids, which is the combination of a fluid-base and nanoparticles to enhance certain desired properties.
We have been investigating convective heat transfer of Newtonian and non-Newtonian nanofluids in cavities via theoretical and computational modeling and simulation utilizing the constructal design concept [1, 2]. The constructal design is based on the constructal law, which was stated by Adrian Bejan in 1996 as follows: "For a finite-size system to persist in time (to live), it must evolve in such a way that it provides easier access to the imposed currents that flow through it" . The constructal law accounts for the universal phenomenon of generation and evolution of design (configuration, shape, structure, pattern, rhythm) . Hence, it will provide a better pathway for thermal design and optimization in engineering problems. For example, one can achieve a higher heat transfer from a fin by modifying the fin's aspect ratio keeping the area ratio (cavity to fin area) constant. As shown below (middle figure) for Al2O3/water nanofluid, average Nusselt number (Nuavg) is 24.5 for the optimum shape at Re = 1000, which is nearly 32% and 110% higher than the lowest and highest aspect ratios of the fin (H1/L1 = 0.1 and H1/L1 = 10) respectively .
2019–2022: “Physics-Based Thermal Degradation Modelling of Lithium-ion Batteries,” Faraday Institution and NU PhD Studentship, Newcastle University (fEC £129,030; PI)
2019–2021: “Thermal and Water Management of Anion Exchange Membrane Fuel Cell,” Libyan Ministry of Higher Education and Scientific Research PhD Studentship, Newcastle University (fEC £108,000; PI)
2018–2021: “Recycling of Li-ion Batteries (ReLiB),” Faraday Institution Research Grant: FIRG005, Newcastle University (fEC £2,531,342; Co-I)
2018–2019: “Tuneable Porous-Transport-Layers for Clean Energy Applications,” STFC Batteries Network Research Grant: ST/R006873/1, Newcastle University (fEC £2,400; PI)
2017–2019: “Novel Porous-Transport-Layers for Fuel Cells and Clean Energy Applications,” EPSRC Research Grant: EP/P03098X/1, Newcastle University (fEC £287,846; PI)
2016–2017: “Interactions between Liquid Water and Gas Diffusion Layers in PEFCs,” STFC Early Career Award, Science and Technology Facilities Council (fEC £3,000; PI)
2015–2019: “Development of Inorganic Catalysts and Prototype Water Splitting Flow Cell for the Photo-electrochemical Water-Splitting Process,” SAgE Doctoral Training Award, Newcastle University (fEC £96,000; Co-I)
2010–2012: “Water Management and Dynamics of Water Transport in PEM Fuel Cells,” Natural Sciences and Engineering Research Council of Canada (grant no. 464238 and 485755), Lawrence Berkeley National Laboratory (fEC $130,000; PI)
2005–2007: “Electrophoresis in Nanoscale Confined Geometries,” Natural Sciences and Engineering Research Council of Canada (grant no. 292594 and 323630), University of Waterloo (C$70,000; PI)
2002–2006: “Design and Simulation of a Colloidal Micro-device Actuated by Surface Potential Modulation in a Straight Cylindrical Capillary,” Alberta Heritage Foundation for Science and Engineering Research, University of Alberta (C$110,000; PI)