Imperial College London

Professor Nigel Brandon OBE FREng

Faculty of Engineering

Dean of the Faculty of Engineering
 
 
 
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Contact

 

+44 (0)20 7594 8600n.brandon Website

 
 
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Location

 

2.06Faculty BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

424 results found

Brandon N, Hagen A, Dawson R, Bucheli Oet al., 2017, “Solid Oxide Fuel Cells, Electrolyzers and Reactors: From Development to Delivery – EFCF2016”, Fuel Cells, Vol: 17, Pages: 414-414, ISSN: 1615-6846

Journal article

Somalu MR, Muchtar A, Daud WRW, Brandon NPet al., 2017, Screen-printing inks for the fabrication of solid oxide fuel cell films: A review, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, Vol: 75, Pages: 426-439, ISSN: 1364-0321

Journal article

Cooper SJ, Bertei A, Finegan DP, Brandon NPet al., 2017, Simulated impedance of diffusion in porous media, Electrochimica Acta, Vol: 251, Pages: 681-689, ISSN: 0013-4686

This paper describes the use of a frequency domain, finite-difference scheme to simulate the impedance spectra of diffusion in porous microstructures. Both open and closed systems are investigated for a range of ideal geometries, as well as some randomly generated synthetic volumes and tomographically derived microstructural data. In many cases, the spectra deviate significantly from the conventional Warburg-type elements typically used to represent diffusion in equivalent circuit analysis. A key finding is that certain microstructures show multiple peaks in the complex plane, which may be misinterpreted as separate electrochemical processes in real impedance data. This is relevant to battery electrode design as the techniques for nano-scale fabrication become more widespread. This simulation tool is provided as an open-source MatLab application and is freely available online as part of the TauFactor platform.

Journal article

Speirs J, Balcombe P, Johnson E, Martin J, Brandon N, Hawkes Aet al., 2017, A Greener Gas Grid: What Are the Options?, A greener gas grid: what are the options?

Report

Chen J, Bertei A, Ruiz-Trejo E, Atkinson A, Brandon NPet al., 2017, Characterization of Degradation in Nickel Impregnated Scandia-Stabilize Zirconia Electrodes during Isothermal Annealing, Journal of The Electrochemical Society, Vol: 164, Pages: F935-F943, ISSN: 1945-7111

This study investigates the stability of nickel-impregnated scandia-stabilize zirconia composite electrodes during isothermal annealing at temperatures from 600 to 950°C in a humidified hydrogen atmosphere (3 vol % water vapor). Typically an initial rapid degradation of the electrode during the first 17 h of annealing is revealed by both an increase in polarization resistance and a fall in electronic conductivity. Secondary electron images show a shift in nickel particle size toward larger values after 50 h of annealing. The declining electrochemical performance is hence attributed to nickel coarsening at elevated temperatures. Nickel coarsening has two microstructural effects: breaking up nickel percolation; and reducing the density of triple phase boundaries. Their impact on electrode area specific resistance is explored using a physical model of electrode performance which relates the macroscopic electrochemical performance to measurable microstructural parameters.

Journal article

Ruiz-Trejo E, Bertei A, Maserati A, Boldrin P, Brandon NPet al., 2017, Oxygen Reduction, Transport and Separation in Low Silver Content Scandia-Stabilized Zirconia Composites, Journal of The Electrochemical Society, Vol: 164, Pages: F3045-F3054, ISSN: 1945-7111

Dense composites of silver and Sc-stabilized ZrO2 (Ag-ScSZ) are manufactured from ScSZ sub-micrometric particles coated with silver using Tollens’ reagent. A composite with 8.6 vol % of silver exhibits metallic conductivity of 186 S cm−1 and oxygen flux of 0.014 μmol cm−2 s−1 at 600°C for a 1-mm thick membrane when used as a pressure-driven separation membrane between air and argon. To gain insight into the role of oxygen transport in Ag and ScSZ, a dense non-percolating sample (Ag 4.7 vol%) is analyzed by impedance spectroscopy and the transport of oxygen through both phases is modelled. Oxygen transport takes place in both silver and ScSZ but it is still dominated by transport in the ionic conductor and therefore a large volume fraction of the ion conductor is beneficial for the separation. The oxygen transport in the silver clusters inside the composite is dominated by diffusion of neutral species and not by the charge transfer reaction at the interface between ScSZ and Ag, yet small silver particles on the surface improve the reduction of oxygen. Oxygen reduction is highly promoted by silver on the surface and there are no limitations of charge transfer at the interface between silver and ScSZ.

Journal article

Bertei A, Ruiz Trejo E, Kareh K, Yufit V, Wang X, Tariq F, Brandon Net al., 2017, The fractal nature of the three-phase boundary: A heuristic approach to the degradation of nanostructured solid oxide fuel cell anodes, Nano Energy, Vol: 38, Pages: 526-536, ISSN: 2211-2855

Nickel/zirconia-based nanostructured electrodes for solid oxide fuel cells suffer from poor stability even at intermediate temperature. This study quantifies the electrochemical and microstructural degradation of nanostructured electrodes by combining 3D tomography, electrochemical impedance spectroscopy (EIS) and mechanistic modeling. For the first time, the electrochemical degradation of nanostructured electrodes is quantified according to the fractal nature of the three-phase boundary (TPB). Using this hypothesis an excellent match between modeling and the electrochemical response is found. The origin of the degradation in microstructure and electrochemical performance can be found in the initial fractal roughness of the TPB at a length scale not detectable with state-of-the-art tomography at 30 nm resolution. This additionally implies that the hydrogen electro-oxidation takes place within 4 nm from the geometric TPB line, revealing that the electrochemical reaction zone cannot be regarded anymore as a one-dimensional line when dealing with nanoparticles.

Journal article

Chen YA, Ji L, Brandon N, Xie M, Scott K, Du W, Yang J, Wu Xet al., 2017, A study on the flow field design of lead flow batteries, 10th International Conference on Lead-Acid Batteries, LABAT 2017, Pages: 199-200

Conference paper

Xie M, Chen Y, Li X, Brandon N, Wu Xet al., 2017, Influences of surfactant additives on performances of lead acid flow batteries, 10th International Conference on Lead-Acid Batteries, LABAT 2017, Pages: 121-122

Conference paper

Brandon NP, Kurban Z, 2017, Clean energy and the hydrogen economy, Philosophical Transactions of the Royal Society A. Mathematical, Physical and Engineering Sciences, Vol: 375, ISSN: 1364-503X

In recent years, new-found interest in the hydrogeneconomy from both industry and academia hashelped to shed light on its potential. Hydrogencan enable an energy revolution by providing muchneeded flexibility in renewable energy systems. Asa clean energy carrier, hydrogen offers a rangeof benefits for simultaneously decarbonizing thetransport, residential, commercial and industrialsectors. Hydrogen is shown here to have synergieswith other low-carbon alternatives, and can enablea more cost-effective transition to de-carbonizedand cleaner energy systems. This paper presentsthe opportunities for the use of hydrogen in keysectors of the economy and identifies the benefitsand challenges within the hydrogen supply chain forpower-to-gas, power-to-power and gas-to-gas supplypathways. While industry players have alreadystarted the market introduction of hydrogen fuelcell systems, including fuel cell electric vehicles andmicro-combined heat and power devices, the use ofhydrogen at grid scale requires the challenges of cleanhydrogen production, bulk storage and distribution tobe resolved. Ultimately, greater government support,in partnership with industry and academia, is stillneeded to realize hydrogen’s potential across alleconomic sectors.

Journal article

Chen Z, Wang X, Brandon N, Atkinson Aet al., 2017, Spherical indentation of bilayer ceramic structures: dense layer on porous substrate, Journal of the European Ceramic Society, Vol: 37, Pages: 4763-4772, ISSN: 1873-619X

Spherical indentation of thin 8YSZ ceramic layers on porous substrates (NiO/Ni-8YSZ) was studied. Indentation-induced elastic and plastic deformation and damage of the bilayer was experimentally analysed. FE simulations of the indentation process were carried out using the Gurson model to account for densification of the porous substrates. The simulated load-depth responses were in excellent agreement with the measured ones. The resulting stress distributions showed that the damage to the YSZ initiates in a tensile region near the interface due to bending during loading at a failure stress of ∼2 GPa, which is consistent with pores of ∼1 μm size seen in the YSZ. Delamination occurs on unloading due to the elastic recovery of YSZ being greater than that of the substrates at a de-bonding stress of 120 MPa. Residual compressive stress in the YSZ inhibits crack opening displacements normal to the layer plane which is beneficial for application of these structures in SOFCs.

Journal article

Ouyang M, Boldrin P, Brandon NP, 2017, Methane Pulse Study on Nickel Impregnated Gadolinium Doped Ceria, 15th International Symposium on Solid Oxide Fuel Cells (SOFC), Publisher: ELECTROCHEMICAL SOC INC, Pages: 1353-1366, ISSN: 1938-5862

Conference paper

Cooper SJ, brandon NP, 2017, Solid Oxide Fuel Cell Lifetime and Reliability, Solid Oxide Fuel Cell Lifetime and Reliability Critical Challenges in Fuel Cells, Editors: Ruiz-Trejo, BOLDRIN, Publisher: Academic Press, Pages: 1-15, ISBN: 9780128097243

For its holistic approach, this book can be used both as an introduction to these issues and a reference resource for all involved in research and application of solid oxide fuel cells, especially those developing understanding in ...

Book chapter

Jais AA, Ali SAM, Anwar M, Somalu MR, Muchtar A, Isahak WNRW, Tan CY, Singh R, Brandon NPet al., 2017, Enhanced ionic conductivity of scandia-ceria-stabilized-zirconia (10Sc1CeSZ) electrolyte synthesized by the microwave-assisted glycine nitrate process, Ceramics International, Vol: 43, Pages: 8119-8125, ISSN: 0272-8842

Scandia-stabilized-zirconia is a potential zirconia-based electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, the properties of zirconia co-doped with 10 mol% Sc and 1 mol% Ce (scandia-ceria-stabilized-zirconia, 10Sc1CeSZ) electrolyte synthesized by the microwave-assisted glycine nitrate process (MW-GNP) were determined. The effects of microwave heating on the sintering temperature, microstructure, densification and ionic conductivity of the 10Sc1CeSZ electrolyte were evaluated. The phase identification, microstructure and specific surface area of the prepared powder were investigated using X-ray diffraction, transmission electron microscopy and the Brunauer-Emmett-Teller technique, respectively. Using microwave heating, a single cubic-phase powder was produced with nanosized crystallites (19.2 nm) and a high specific surface area (16 m2/g). It was found that the relative density, porosity and total ionic conductivity of the 10Sc1CeSZ electrolyte are remarkably influenced by the powder processing method and the sintering temperature. The pellet sintered at 1400 °C exhibited a maximum ionic conductivity of 0.184 S/cm at 800 °C. This is the highest conductivity value of a scandia-stabilized-zirconia based electrolyte reported in the literature for this electrolyte type. The corresponding value of the activation energy of electrical conductivity was found to be 0.94 eV in the temperature range of 500–800 °C. Overall, the use of microwave heating has successfully improved the properties of the 10Sc1CeSZ electrolyte for application in an IT-SOFC.

Journal article

Somalu MR, Muchtar A, Brandon NP, 2017, Properties of screen-printed nickel/scandia-stabilized-zirconia anodes fabricated using rheologically optimized inks during redox cycles, JOURNAL OF MATERIALS SCIENCE, Vol: 52, Pages: 7175-7185, ISSN: 0022-2461

Journal article

Jamil Z, Ruiz-Trejo E, Brandon NP, 2017, Nickel Electrodeposition on Silver for the Development of Solid Oxide Fuel Cell Anodes and Catalytic Membranes, Journal of The Electrochemical Society, Vol: 164, Pages: D210-D217, ISSN: 1945-7111

Nickel was electrodeposited on porous Ag/GDC (silver/Ce0.9Gd0.1O2-x) scaffolds and dense Ag/GDC composites for the fabricationof SOFC electrodes and catalytic membranes respectively. To control the distribution and amount of nickel deposition on the Ag/GDCsurfaces; first, a systematic cyclic voltammetry study of nickel electrodeposition from a Watts bath on silver foils was carried outto understand the influence of operating conditions on the electrodeposition process. From the cyclic voltammetry study, it can beconcluded that suitable operating conditions for nickel electrodeposition into porous Ag/GDC scaffolds and catalytic membranesare: 1.1 M Ni2+ concentration in Watts bath; deposition potential between −0.65 to −1.0 V vs. Ag/AgCl; a temperature at 55◦C;sodium dodecyl sulfate (SDS) as the surfactant; pH 4.0 ± 0.2 and an agitation rate of 500 rpm. It was observed that the nickel surfacemicrostructure changed with the deposition current densities due to the co-evolution of H2. Pulse and continuous electrodepositionmodes allow nickel to be deposited throughout porous Ag/GDC scaffolds and onto catalytic membranes. The pulse electrodepositionmode is favored as this is shown to result in an even Ni distribution within the porous scaffolds at minimum H2 pitting.

Journal article

Chen Z, Atkinson A, Brandon N, 2017, Characterization of deformation and damage in porous sofc components via spherical indentation and simulation, 40th International Conference on Advanced Ceramics and Composites, Pages: 143-157

© 2018 by World Scientific Publishing Europe Ltd. The aim of this work is to present the methodology to characterize deformation and contact damage initiation and evolution in porous bulk and film components used in solid oxide fuel cells, based on indentation and simulation. Spherical indentation tests at a broad range of loads (50-10000 mN) were carried out on porous bulk and film electrodes with different levels of porosity, and on bilayer system. An axisymmetric model based on the Gurson model used for porous materials was developed to simulate the indentation processes. Elasticity and hardness of each component were reliably determined via both experiments and modelling. Inverse analysis via comparison of experimental indentation response curves and simulation-generated curves shows a very different relation between hardness and yield stress, compared with dense materials. Cracking behaviour was examined and appropriately explained by FEM results. Further insight of the deformation and damage behaviour was also obtained based on microstructural study using FIB-SEM. Overall, the study shows that the model developed in this work is highly applicable for the description the deformation and damage characteristics in porous bulk and film ceramics.

Conference paper

Cooper SJ, Brandon NP, 2017, An Introduction to Solid Oxide Fuel Cell Materials, Technology and Applications, ISBN: 9780081011027

© 2017 Elsevier Ltd. All rights reserved. This chapter begins with a brief history of fuel cell development and introduces solid oxide fuel cells (SOFCs) as high efficiency energy conversion devices. Following this the fundamentals of SOFC performance and cell design are explored, with special focus given to the significance of operating temperature and microstructure. Next the current commercial status of SOFCs is outlined in brief. Finally, SOFC degradation, the major theme of this book, is introduced; the various mechanisms are split into the two broad categories of physical and chemical degradation.

Book

Tariq F, Ruiz-Trejo E, Bertei A, Boldrin P, Brandon NPet al., 2017, Microstructural Degradation: Mechanisms, Quantification, Modeling and Design Strategies to Enhance the Durability of Solid Oxide Fuel Cell Electrodes, Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells, Pages: 79-99, ISBN: 9780081011027

© 2017 Elsevier Ltd. All rights reserved. Electrode microstructure is one of the main factors determining the performance and durability of solid oxide fuel cells (SOFCs). The degradation is intimately linked to the microstructure, which in turn depends upon manufacturing and operation conditions. In this chapter we discuss the main causes for degradation of electrodes, concentrating mainly on the anode and present the techniques-both typical and state-of-the-art to follow these changes. We emphasize the need to quantitatively link the microstructural properties (e.g., triple-phase boundaries, porosity, and tortuosity) with the electrochemical responses measured and, most importantly, to link the change in microstructure to the performance degradation via suitable models. The knowledge gained must then be used to design new electrodes that can extend the lifetime of SOFCs once the critical parameters have been identified.

Book chapter

Brandon NP, Ruiz-Trejo E, Boldrin P, 2017, Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells, ISBN: 9780081011027

© 2017 Elsevier Ltd. All rights reserved. Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells presents in one volume the most recent research that aims at solving key issues for the deployment of SOFC at a commercial scale and for a wider range of applications. To achieve that, authors from different regions and backgrounds address topics such as electrolytes, contaminants, redox cycling, gas-tight seals, and electrode microstructure. Lifetime issues for particular elements of the fuel cells, like cathodes, interconnects, and fuel processors, are covered as well as new materials. They also examine the balance of SOFC plants, correlations between structure and electrochemical performance, methods for analysis of performance and degradation assessment, and computational and statistical approaches to quantify degradation. For its holistic approach, this book can be used both as an introduction to these issues and a reference resource for all involved in research and application of solid oxide fuel cells, especially those developing understanding in industrial applications of the lifetime issues. This includes researchers in academia and industrial R&D, graduate students and professionals in energy engineering, electrochemistry, and materials sciences for energy applications. It might also be of particular interest to analysts who are looking into integrating SOFCs into energy systems. Brings together in a single volume leading research and expert thinking around the broad topic of SOFC lifetime and durability. Explores issues that affect solid oxide fuel cells elements, materials, and systems with a holistic approach. Provides a practical reference for overcoming some of the common failure mechanisms of SOFCs. Features coverage of integrating SOFCs into energy systems.

Book

Chen J, Ruiz-Trejo E, Atkinson A, Brandon NPet al., 2017, Microstructural and Electrochemical Characterisation of Degradation in Nickel Impregnated Scandia-stabilised Zirconia Electrode during Isothermal Annealing, 15th International Symposium on Solid Oxide Fuel Cells (SOFC), Publisher: ELECTROCHEMICAL SOC INC, Pages: 1125-1137, ISSN: 1938-5862

Conference paper

Mukerjee S, Leah R, Selby M, Stevenson G, Brandon NPet al., 2017, Life and Reliability of Solid Oxide Fuel Cell-Based Products: A Review, Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells, Pages: 173-191, ISBN: 9780081011027

© 2017 Elsevier Ltd. All rights reserved. Solid oxide fuel cells (SOFCs) are a technology rapidly developing toward widespread commercialization, with hundreds of megawatts of generation capacity installed in the field for large-scale power generation (100. kW-1. MW), and small-scale distributed power generation (<5. kW scale) undergoing large precommercial field trials in Europe and Japan. Although rapidly improving, challenges still remain in achieving SOFC stack operating lives of up to 90,000. h at a cost competitive with more established power generation technology. This chapter provides a review of the current development status of the main SOFC developers and technology variants based on publicly available literature. The techniques being developed to accelerate technology development cycles by enabling lifetime prediction from relatively short-duration tests are also discussed.

Book chapter

Bertei A, Tariq F, Yufit V, Ruiz Trejo E, Brandon Net al., 2016, Guidelines for the rational design and engineering of 3D manufactured solid oxide fuel cell composite electrodes, Journal of the Electrochemical Society, Vol: 164, Pages: F89-F98, ISSN: 0013-4651

The growth of 3D printing has opened the scope for designing microstructures for solid oxide fuel cells(SOFCs) with improved power density and lifetime. This technique can introduce structural modifications at a scale larger than particle size but smaller than cell size, such as by insertingelectrolyte pillars of ~5-100 µm. This study sets the minimum requirements for the rational design of 3D printedelectrodes based on an electrochemical model and analytical solutions for functional layers with negligible electronic resistanceand no mixed conduction. Results show that this structural modification enhances the power density when the ratio keffbetween effective conductivity and bulk conductivity of the ionic phase is smaller than 0.5. The maximum performance improvement is predicted as a function of keff. A design study on a wide range of pillar shapes indicates that improvements are achieved by any structural modification which provides ionic conduction up to a characteristic thickness ~10-40 µm without removing active volume at the electrolyte interface. The best performance is reached for thin (< ~2 µm) and long (> ~80 µm) pillars when the compositeelectrode is optimised for maximum three-phase boundarydensity, pointing towards the design of scaffolds with well-defined geometry and fractal structures.

Journal article

Parkes MA, Tompsett DA, d'Avezac M, Offer GJ, Brandon NP, Harrison NMet al., 2016, The atomistic structure of yttria stabilised zirconia at 6.7 mol%: an ab initio study., Physical Chemistry Chemical Physics, Vol: 18, Pages: 31277-31285, ISSN: 1463-9084

Yttria stabilized zirconia (YSZ) is an important oxide ion conductor used in solid oxide fuel cells, oxygen sensing devices, and for oxygen separation. Doping pure zirconia (ZrO2) with yttria (Y2O3) stabilizes the cubic structure against phonon induced distortions and this facilitates high oxide ion conductivity. The local atomic structure of the dopant is, however, not fully understood. X-ray and neutron diffraction experiments have established that, for dopant concentrations below 40 mol% Y2O3, no long range order is established. A variety of local structures have been suggested on the basis of theoretical and computational models of dopant energetics. These studies have been restricted by the difficulty of establishing force field models with predictive accuracy or exploring the large space of dopant configurations with first principles theory. In the current study a comprehensive search for all symmetry independent configurations (2857 candidates) is performed for 6.7 mol% YSZ modelled in a 2 × 2 × 2 periodic supercell using gradient corrected density functional theory. The lowest energy dopant structures are found to have oxygen vacancy pairs preferentially aligned along the ⟨210⟩ crystallographic direction in contrast to previous results which have suggested that orientation along the ⟨111⟩ orientation is favourable. Analysis of the defect structures suggests that the Y(3+)-Ovac interatomic separation is an important parameter for determining the relative configurational energies. Current force field models are found to be poor predictors of the lowest energy structures. It is suggested that the energies from a simple point charge model evaluated at unrelaxed geometries is actually a better descriptor of the energy ordering of dopant structures. Using these observations a pragmatic procedure for identifying low energy structures in more complicated material models is suggested. Calculation of the oxygen vacancy migration activat

Journal article

Boldrin P, Ruiz Trejo E, Mermelstein J, Bermudez Menendez J, Ramirez Reina T, Brandon Net al., 2016, Strategies for carbon and sulfur tolerant solid oxide fuel cell materials, incorporating lessons from heterogeneous catalysis, Chemical Reviews, Vol: 116, Pages: 13633-13684, ISSN: 1520-6890

Solid oxide fuel cells (SOFCs) are a rapidly emerging energy technology for a low carbon world, providing high efficiency, potential to use carbonaceous fuels and compatibility with carbon capture and storage. However, current state-of-the-art materials have low tolerance to sulfur, a common contaminant of many fuels, and are vulnerable to deactivation due to carbon deposition when using carbon-containing compounds. In this review we first study the theoretical basis behind carbon and sulfur poisoning, before examining the strategies towards carbon and sulfur tolerance used so far in the SOFC literature. We then study the more extensive relevant heterogeneous catalysis literature for strategies and materials which could be incorporated into carbon and sulfur tolerant fuel cells.

Journal article

Chakrabarti BK, Nir DP, Yufit V, Tariq F, Rubio Garcia J, Maher R, Kucernak A, Aravind PV, Brandon NPet al., 2016, Studies of performance enhancement of rGO-modified carbon electrodes for Vanadium Redox Flow Systems, ChemElectroChem, Vol: 4, Pages: 194-200, ISSN: 2196-0216

Reduced graphene oxide (rGO) suspended in an N,N′-dimethylformamide (DMF) solvent underwent electrophoretic deposition (EPD) on carbon paper (CP) electrodes. X-ray computed micro-tomography (XMT) indicates a 24 % increase in the specific surface area of CP modified with rGO in comparison to the untreated sample. Furthermore, XMT confirms that the deposition also penetrates into the substrate. Raman analysis shows that the rGO deposited is more amorphous than the CP electrode. A significant reduction in charge-transfer resistance of the VO2+/VO2+ reaction is also observed (from impedance measurements) in modified samples in comparison to untreated CP electrodes.

Journal article

Cooper SJ, Bertei A, Shearing PR, Kilner JA, Brandon NPet al., 2016, TauFactor: An open-source application for calculating tortuosity factors from tomographic data, SoftwareX, Vol: 5, Pages: 203-210, ISSN: 2352-7110

TauFactor is a MatLab application for efficiently calculating the tortuosity factor, as well as volume fractions, surface areas and triple phase boundary densities, from image based microstructural data. The tortuosity factor quantifies the apparent decrease in diffusive transport resulting from convolutions of the flow paths through porous media. TauFactor was originally developed to improve the understanding of electrode microstructures for batteries and fuel cells; however, the tortuosity factor has been of interest to a wide range of disciplines for over a century, including geoscience, biology and optics. It is still common practice to use correlations, such as that developed by Bruggeman, to approximate the tortuosity factor, but in recent years the increasing availability of 3D imaging techniques has spurred interest in calculating this quantity more directly. This tool provides a fast and accurate computational platform applicable to the big datasets (>10^8 voxels) typical of modern tomography, without requiring high computational power.

Journal article

Chen Z, Wang X, Brandon N, Atkinson Aet al., 2016, Analysis of spherical indentation of porous ceramic films, Journal of the European Ceramic Society, Vol: 37, Pages: 1031-1038, ISSN: 1873-619X

Spherical indentation of a porous brittle La0.6Sr0.4Co0.2Fe0.8O3 ceramic film (porosity=39.7%) on a stiffer elastic Ce0.9Gd0.1O1.95 substrate is simulated by finite element modelling incorporating the Gurson model to account for densification. The simulated load-displacement curves, apparent elastic modulus E, indentation hardness H and densification profile are all in good agreement with experimental data for the film. The simulations show that E and H are not sensitive to film residual stress. However E is very sensitive to the indent depth-film thickness ratio f, although H is less so for f<0.3. The simulated dependence of E and H on f are highly consistent with experimental data, supporting the extrapolation of E and H measured for 0.1<f<0.3, to zero depth for good estimates of the film-alone properties. The inclusion of densification in the simulation makes only a small difference to E, but has a large influence on H as a function of indentation depth.

Journal article

Ruiz Trejo E, Puolamaa M, Sum B, Tariq F, Yufit V, Brandon NPet al., 2016, New method for the deposition of nickel oxide in porous scaffolds for electrodes in solid oxide fuel cells and electrolyzers, Chemsuschem, Vol: 10, Pages: 258-265, ISSN: 1864-564X

A simple chemical bath deposition is used to coat a complex porous ceramic scaffold with a conformal nickel layer. The resulting composite is used as a Solid Oxide Fuel Cell electrode and its electrochemical response is measured in humidified hydrogen. X-Ray tomography is used to determine microstructural parameters of the uncoated and Ni-coated porous structure, among other, the surface area to total volume, the radial pore size and size of the necks between pores.

Journal article

Liu X, Jervis R, Maher RC, Villar Garcia I, Naylor Marlow M, Shearing P, Ouyang M, Cohen L, Brandon N, Wu Bet al., 2016, 3D-Printed Structural Pseudocapacitors, Advanced Materials Technologies, Vol: 1, ISSN: 2365-709X

Direct metal laser sintering is used to create 3D hierarchical porous metallic scaffolds which are then functionalized with a co-electrodeposition of MnO2, Mn2O3, and doped conducting polymer. This approach of functionalizing metal 3D printed scaffolds thus opens new possibilities for structural energy storage devices with enhanced performance and lifetime characteristics.

Journal article

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