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

402 results found

Bahadori L, Chakrabarti MH, Manan NSA, Hashim MA, Mjalli FS, AlNashef IM, Brandon Net al., 2015, The effect of temperature on kinetics and diffusion coefficients of metallocene derivatives in polyol-based deep eutectic solvents, PLOS One, Vol: 10, ISSN: 1932-6203

The temperature dependence of the density, dynamic viscosity and ionic conductivity of several deep eutectic solvents (DESs) containing ammonium-based salts and hydrogen bond donvnors (polyol type) are investigated. The temperature-dependent electrolyte viscosity as a function of molar conductivity is correlated by means of Walden’s rule. The oxidation of ferrocene (Fc/Fc+) and reduction of cobaltocenium (Cc+/Cc) at different temperatures are studied by cyclic voltammetry and potential-step chronoamperometry in DESs. For most DESs, chronoamperometric transients are demonstrated to fit an Arrhenius-type relation to give activation energies for the diffusion of redox couples at different temperatures. The temperature dependence of the measured conductivities of DES1 and DES2 are better correlated with the Vogel-Tamman-Fulcher equation. The kinetics of the Fc/Fc+ and Cc+/Cc electrochemical systems have been investigated over a temperature range from 298 to 338 K. The heterogeneous electron transfer rate constant is then calculated at different temperatures by means of a logarithmic analysis. The glycerol-based DES (DES5) appears suitable for further testing in electrochemical energy storage devices.

JOURNAL ARTICLE

Dewage HH, Yufit V, Brandon NP, 2015, Study of Loss Mechanisms Using Half-Cell Measurements in a Regenerative Hydrogen Vanadium Fuel Cell, Journal of the Electrochemical Society, Vol: 163, Pages: A5236-A5243, ISSN: 0013-4651

The positioning of reference electrodes in redox flow batteries without disturbing the cell operation represents a great challenge. However decoupling anode and cathode processes is crucial in order to fully understand the losses in the system so it can be further optimized. The feasibility of a regenerative fuel cell based on an V(IV)/V(V) electrolyte and hydrogen gas has previously been demonstrated. In this investigation, using electrochemical impedance spectroscopy, the various losses of the cathode, anode and whole cell were established using an alternative reference electrode set-up. The findings showed that the largest irreversible losses under the conditions tested arose from diffusion limitations in the cathode and the effect of vanadium crossover and therefore adsorption onto the platinum layer of the hydrogen electrode leading to higher losses on the anode. These results highlight the potential for further improvement and optimization of cell design and materials for both electrodes in the Regenerative Hydrogen Vanadium Fuel Cell.

JOURNAL ARTICLE

Tonekabonimoghadam S, Akikur RK, Hussain MA, Hajimolana S, Saidur R, Ping HW, Chakrabarti MH, Brandon NP, Aravind PV, Nayagar JNS, Hashim MAet al., 2015, Mathematical modelling and experimental validation of an anode-supported tubular solid oxide fuel cell for heat and power generation, ENERGY, Vol: 90, Pages: 1759-1768, ISSN: 0360-5442

JOURNAL ARTICLE

Balcombe P, Anderson K, Speirs J, Brandon N, Hawkes Aet al., 2015, Methane and CO2 emissions from the natural gas supply chain: an evidence assessment, Publisher: Sustainable Gas Institute

REPORT

Chakrabarti MH, Manan NSA, Brandon NP, Maher RC, Mjalli FS, AlNashef IM, Hajimolana SA, Hashim MA, Hussain MA, Nir Det al., 2015, One-pot electrochemical gram-scale synthesis of graphene using deep eutectic solvents and acetonitrile, CHEMICAL ENGINEERING JOURNAL, Vol: 274, Pages: 213-223, ISSN: 1385-8947

JOURNAL ARTICLE

Lomberg M, Boldrin P, Tariq F, Offer G, Wu B, Brandon NPet al., 2015, Additive manufacturing for solid oxide cell electrode fabrication, ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV, Publisher: Electrochemical Society, Pages: 2119-2127, ISSN: 1938-6737

Additive manufacturing can potentially offer a highly-defined electrode microstructure, as well as fast and reproducible electrode fabrication. Selective laser sintering is an additive manufacturing technique in which three-dimensional structures are created by bonding subsequent layers of powder using a laser. Although selective laser sintering can be applied to a wide range of materials, including metals and ceramics, the scientific and technical aspects of the manufacturing parameters and their impact on microstructural evolution during the process are not well understood. In the present study, a novel approach for electrode fabrication using selective laser sintering was evaluated by conducting a proof of concept study. A Ni-patterned fuel electrode was laser sintered on an yttria-stabilized zirconia substrate. The optimization process of laser parameters (laser sintering rate and laser power) and the electrochemical results of a full cell with a laser sintered electrode are presented. The challenges and prospects of using selective laser sintering for solid oxide cell fabrication are discussed.

CONFERENCE PAPER

Boldrin P, Ruiz Trejo E, Tighe C, Chang KC, Darr J, Brandon NPet al., 2015, Impregnation of nanoparticle scaffolds for syngas-fed solid oxide fuel cell anodes, ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV, Publisher: Electrochemical Society, Pages: 1219-1227, ISSN: 1938-6737

A strategy for fabrication of solid oxide fuel cell anodes with improved porosity and lower sintering temperatures by impregnation of nanoparticle-containing porous scaffolds of ceria-gadolinia (CGO) has been developed. The CGO scaffolds are fabricated using a screen-printed ink containing nanoparticles and commercial particles of CGO and polymeric pore formers. Scanning electron microscopy and in situ ultra-small angle X-ray scattering show that incorporation of nanoparticles increases the porosity by allowing a reduction in sintering temperature. Electrochemical characterisation of symmetrical cells shows that the cells sintered at 1000°C possess similar electrode polarisation compared to those sintered at 1300°C. Button cell testing showed that reducing the sintering temperature produced cells which perform better at 700°C and below in hydrogen, and performed better at all temperatures using syngas. This approach has the potential to allow the use of a wider range of nanomaterials, giving a finer control over microstructure.

CONFERENCE PAPER

Mazur CM, Brandon, Offer, Contestabileet al., 2015, Understanding the drivers of fleet emission reduction activities of the German car manufacturers, Environmental Innovation and Societal Transitions, Vol: 16, Pages: 3-21, ISSN: 2210-4224

The current mobility system, dominated by fossil fuel poweredautomobiles, is under increasing pressure due to its environmentalimpact. To address this issue there is a need for a transitionof the system towards one that is more sustainable, including theintroduction of car technologies that allow a decrease in fuel consumptionand the substitution of fossil fuels as primary energysource. Due to the stability of the current automotive industryand the dominance of the internal combustion engine technology,it is expected that the incumbent firms and their activities willplay a crucial role in the transition. Policy makers have thereforeintroduced a variety of policies to encourage the industry to providesuitable solutions.We have conducted amicro-level analysis of howthe threemain German carmanufacturers have changed their activitiesin the field of low emission vehicle technologies in response tonational/international events and policy making. Our analysis suggeststhat policy makers only have limited influence on the typeof disruptive solution that is chosen by these individual companiesand that activities related to solutions that were not familiar to theindividual car manufacturer were mainly induced by internal or external champions. Still, while the existence of regulatory policiesallowed such activities to succeed, on its own it only encouraged theindustry to work on incremental solutions based upon the knowledgealready possessed.

JOURNAL ARTICLE

Green RJ, staffell I, Hamilton IG, 2015, The residential energy sector, Domestic Microgeneration Renewable and Distributed Energy Technologies, Policies and Economics, Editors: Staffell, Brandon, Hawkes, Brett, Publisher: Routledge, Pages: 18-48, ISBN: 9781317448853

1 Overview Whilst the primary use of microgeneration is to service the energy demands of a building or a community, microgeneration technologies could also play a role in wider energy networks such as communal heating schemes or (more ...

BOOK CHAPTER

Bahadori L, Chakrabarti MH, Hashim MA, Manan NSA, Mjalli FS, AlNashef IM, Brandon NPet al., 2015, Temperature Effects on the Kinetics of Ferrocene and Cobaltocenium in Methyltriphenylphosphonium Bromide Based Deep Eutectic Solvents, Journal of the Electrochemical Society, Vol: 162, Pages: H617-H624, ISSN: 0013-4651

The oxidation of ferrocene (Fc/Fc+) and reduction of cobaltocenium (Cc+/Cc) under different temperatures has been studied by cyclic voltammetry and double potential step chronoamperometry in deep eutectic solvents (DESs) consisting of methyltriphenylphosphonium bromide salt with tri-ethylene glycol, glycerol or ethylene glycol as hydrogen bond donors. The temperature dependence of the measured physical properties of DESs (such as viscosity and conductivity) is discussed in detail. The kinetics of the redox couples are studied using cyclic voltammetry, and the standard heterogeneous electron transfer rate constant, k0 is found to be of the order of 10−5 to 10−4 cms−1 at different temperatures. The diffusion coefficient, D, of Fc and Cc+ is determined to lie between 8.28 × 10−10 to 6.65 × 10−9 cm2 s−1. These results show that both k0 and D increase with temperature in the studied DESs. In addition, better kinetic parameters for the DES with ethylene glycol as hydrogen bond donor means that this could be evaluated favorably as both solvents and electrolytes for redox flow cells.

JOURNAL ARTICLE

Duboviks V, Lomberg M, Maher RC, Cohen LF, Brandon NP, Offer GJet al., 2015, Carbon deposition behaviour in metal-infiltrated gadolinia doped ceria electrodes for simulated biogas upgrading in solid oxide electrolysis cells, Journal of Power Sources, Vol: 293, Pages: 912-921, ISSN: 1873-2755

One of the attractive applications for reversible Solid Oxide Cells (SOCs) is to convert CO2 into CO via high temperature electrolysis, which is particularly important for biogas upgrading. To improve biogas utility, the CO2 component can be converted into fuel via electrolysis. A significant issue for SOC operation on biogas is carbon-induced catalyst deactivation. Nickel is widely used in SOC electrodes for reasons of cost and performance, but it has a low tolerance to carbon deposition. Two different modes of carbon formation on Ni-based electrodes are proposed in the present work based on ex-situ Raman measurements which are in agreement with previous studies. While copper is known to be resistant towards carbon formation, two significant issues have prevented its application in SOC electrodes – namely its relatively low melting temperature, inhibiting high temperature sintering, and low catalytic activity for hydrogen oxidation. In this study, the electrodes were prepared through a low temperature metal infiltration technique. Since the metal infiltration technique avoids high sintering temperatures, Cu–Ce0.9Gd0.1O2−δ (Cu-CGO) electrodes were fabricated and tested as an alternative to Ni-CGO electrodes. We demonstrate that the performance of Cu-CGO electrodes is equivalent to Ni-CGO electrodes, whilst carbon formation is fully suppressed when operated on biogas mixture.

JOURNAL ARTICLE

Parkes MA, Refson K, d'Avezac M, Offer GJ, Brandon NP, Harrison NMet al., 2015, Chemical descriptors of yttria-stabilized zirconia at low defect concentration: an ab initio study., Journal of Physical Chemistry A, Vol: 119, Pages: 6412-6420, ISSN: 1520-5215

Yttria-stabilized zirconia (YSZ) is an important oxide ion conductor with applications in solid oxide fuel cells (SOFCs) and oxygen sensing devices. Doping the cubic phase of zirconia (c-ZrO2) with yttria (Y2O3) is isoelectronic, as two Zr(4+) ions are replaced by two Y(3+) ions, plus a charge compensating oxygen vacancy (Ovac). Typical doping concentrations include 3, 8, 10, and 12 mol %. For these concentrations, and all below 40 mol %, no phase with long-range order has been observed in either X-ray or neutron diffraction experiments. The prediction of local defect structure and the interaction between defects is therefore of great interest. This has not been possible to date as the number of possible defect topologies is very large and to perform reliable total energy calculations for all of them would be prohibitively expensive. Previous theoretical studies have only considered a selection of representative structures. In this study, a comprehensive search for low-energy defect structures using a combined classical modeling and density functional theory approach is used to identify the low-energy isolated defect structures at the dilute limit, 3.2 mol %. Through analysis of energetics computed using the best available Born-Mayer-Huggins empirical potential model, a point charge model, DFT, and a local strain energy estimated in the harmonic approximation, the main chemical and physical descriptors that correlate to the low-energy DFT structures are discussed. It is found that the empirical potential model reproduces a general trend of increasing DFT energetics across a series of locally strain relaxed structures but is unreliable both in predicting some incorrect low-energy structures and in finding some metastable structures to be unstable. A better predictor of low-energy defect structures is found to be the total electrostatic energy of a simple point charge model calculated at the unrelaxed geometries of the defects. In addition, the strain relaxation energ

JOURNAL ARTICLE

Teng F, Pudjianto D, Strbac G, Brandon N, Thomson A, Miles Jet al., 2015, Potential value of energy storage in the UK electricity system, Proceedings of the ICE - Energy, Vol: 168, Pages: 107-117, ISSN: 1751-4223

This paper assesses the value of distributed energy storage and informs the business case for its multiple applications in the UK electricity system. In contrast to earlier studies that focus on the benefits of energy storage for system operation and development, this work analyses the value that it may deliver to the owner. For this purpose, three models are proposed and applied to analyse the benefit of energy storage with applications in energy and ancillary service markets, revenue maximisation in the context of feed-in tariffs and reduction of carbon dioxide emissions. A large set of studies is carried out to quantify the commercial and emissions benefits of energy storage for those applications. Sensitivity analysis across various scenarios is performed to understand the key drivers for the value of energy storage and how it is affected by energy storage parameters and other factors such as network constraints, prices of energy and ancillary services, and inherent energy system characteristics. A review of current and near-term storage technology costs and functionality is also presented.

JOURNAL ARTICLE

Rhazaoui K, Cai Q, Kishimoto M, Tariq F, Somalu MR, Adjiman CS, Brandon NPet al., 2015, Towards the 3D Modelling of the Effective Conductivity of Solid Oxide Fuel Cell Electrodes - Validation against experimental measurements and prediction of electrochemical performance, Electrochimica Acta, Vol: 168, Pages: 139-147, ISSN: 1873-3859

The effective conductivity of thick-film solid oxide fuel cell (SOFC) electrodes plays a key role in their performance. It determines the ability of the electrode to transport charge to/from reaction sites to the current collector and electrolyte. In this paper, the validity of the recently proposed 3D resistor network model for the prediction of effective conductivity, the ResNet model, is investigated by comparison to experimental data. The 3D microstructures of Ni/10ScSZ anodes are reconstructed using tomography through the focused ion beam and scanning electron microscopy (FIB-SEM) technique. This is used as geometric input to the ResNet model to predict the effective conductivities, which are then compared against the experimentally measured values on the same electrodes. Good agreement is observed, supporting the validity of the ResNet model for predicting the effective conductivity of SOFC electrodes. The ResNet model is then combined with the volume-of-fluid (VOF) method to integrate the description of the local conductivity (electronic and ionic) in the prediction of electrochemical performance. The results show that the electrochemical performance is in particular sensitive to the ionic conductivity of the electrode microstructure, highlighting the importance of an accurate description of the local ionic conductivity.

JOURNAL ARTICLE

Hewa Dewage HARINI, wu BILLY, Tsoi ANTHONY, Yufit VLADIMIR, Offer GREGORY, Brandon NIGELet al., 2015, A novel regenerative hydrogen cerium fuel cell for energy storage applications, Journal of Materials Chemistry A, Vol: 3, Pages: 9446-9450, ISSN: 2050-7496

A novel regenerative hydrogen cerium fuel cell is presented which has the potential to deliver both low cost and high performance. A 5 cm2 prototype is demonstrated, achieving 148 mW cm−2 when fully charged. Rate determining processes within the cell are identified.

JOURNAL ARTICLE

Ruiz-Trejo E, Zhou Y, Brandon NP, 2015, On the manufacture of silver-BaCe0.5Zr0.3Y0.16Zn0.04O3−δ composites for hydrogen separation membranes, International Journal of Hydrogen Energy, Vol: 40, Pages: 4146-4153, ISSN: 1879-3487

Silver- BaCe0.5Zr0.3Y0.16Zn0.04O3−δ (Ag/BCZYZ) composites were investigated due to their potential application as hydrogen separation membranes, with emphasis on their fabrication and characterization. A precursor powder of BCZYZ was prepared via a wet chemical route and characterized by XRD, SEM and dilatometry. The precursor powder was coated with silver using Tollens reaction and then sintered under a variety of conditions. It was possible to obtain dense samples with a low level of non-percolating silver (2 vol%). Silver was present even if sintered at 1300 °C as it remained trapped in the ceramic matrix. The overall conductivity of a dense sample with 2 vol% of silver increased when compared to pure BCZYZ, and in particular the grain boundary resistance decreased considerably. A measurement of the open circuit voltage in fuel cell mode indicates the presence of mixed electronic-protonic conductivity in the composite.

JOURNAL ARTICLE

Stockford C, Brandon N, Irvine J, Mays T, Metcalfe I, Book D, Ekins P, Kucernak A, Molkov V, Steinberger-Wilckens R, Shah N, Dodds P, Dueso C, Samsatli S, Thompson Cet al., 2015, H2FC SUPERGEN: An overview of the Hydrogen and Fuel Cell research across the UK, International Journal of Hydrogen Energy, Vol: 40, Pages: 5534-5543, ISSN: 1879-3487

The United Kingdom has a vast scientific base across the entire Hydrogen and Fuel Cell research landscape, with a world class academic community coupled with significant industrial activity from both UK-based Hydrogen and Fuel Cell companies and global companies with a strong presence within the country. The Hydrogen and Fuel Cell (H2FC) SUPERGEN Hub, funded by the Engineering and Physical Sciences Research Council (EPSRC), was established in 2012 as a five-year programme to bring the UK's H2FC research community together. Here we present the UK's current Hydrogen and Fuel Cell activities along with the role of the H2FC SUPERGEN Hub.

JOURNAL ARTICLE

Mazur C, Contestabile M, Offer GJ, Brandon NPet al., 2015, Assessing and comparing German and UK transition policies for electric mobility, ENVIRONMENTAL INNOVATION AND SOCIETAL TRANSITIONS, Vol: 14, Pages: 84-100, ISSN: 2210-4224

JOURNAL ARTICLE

Ruiz-Trejo E, Boldrin P, Medley-Hallam JL, Darr J, Atkinson A, Brandon NPet al., 2015, Partial oxidation of methane using silver/gadolinia-doped ceria composite membranes, Chemical Engineering Science, Vol: 127, Pages: 269-275, ISSN: 1873-4405

Methane was partially oxidised to CO using oxygen permeated through a 1 mm thick silver/Ce0.9Gd0.1O2−x (Ag/CGO) composite membrane operating at 500–700 °C with air at 1 bar pressure. The membranes were fabricated by sintering ultrafine nanoparticles of gadolinia-doped ceria (<5 nm) coated with silver using Tollens׳ reaction. This unique combination led to dense composites with low content of silver (7 vol%), no reaction between the components and predominant metallic conductivity. When feeding 4% methane at 700 °C to a 1-mm thick Ag/CGO using Ni as reforming catalyst, the conversion reached 21% and the CO selectivity 92% with an estimated oxygen flux of 0.18 mL min−1 cm−2 (NTP). The samples were stable in carbon-containing atmospheres and under a large pO2 transmembrane pressure difference at temperatures below 700 °C for 48 h.

JOURNAL ARTICLE

Ruiz-Trejo E, Atkinson A, Brandon NP, 2015, Metallizing porous scaffolds as an alternative fabrication method for solid oxide fuel cell anodes, Journal of Power Sources, Vol: 280, Pages: 81-89, ISSN: 1873-2755

A combination of electroless and electrolytic techniques is used to incorporate nickel into a porous Ce0.9Gd0.1O1.90 scaffold. First a porous backbone was screen printed into a YSZ electrolyte using an ink that contains sacrificial pore formers. Once sintered, the scaffold was coated with silver using Tollens' reaction followed by electrodeposition of nickel in a Watts bath. At high temperatures the silver forms droplets enabling direct contact between the gadolinia-doped ceria and nickel. Using impedance spectroscopy analysis in a symmetrical cell a total area specific resistance of 1 Ωcm2 at 700 °C in 97% H2 with 3% H2O was found, indicating the potential of this fabrication method for scaling up.

JOURNAL ARTICLE

Somalu MR, Muchtar A, Brandon NP, 2015, Understanding the rheology of screen-printing inks for the fabrication of SOFC thick films, Pages: 1323-1331, ISSN: 1938-5862

© The Electrochemical Society. Fabrication of SOFC components by screen-printing using an optimized ink is very significant for the production of high quality films with improved performance. Understanding the correlation between the composition and rheology of the inks may enhance the properties screen-printed films. In this study, the rheological properties of NiO/ScSZ anode inks were studied and correlated to the particle network strength, screen-printability and film properties. All the inks were fabricated using a triple roll mill. The dynamic study showed that inks having particle network strength and complex modulus in the range of 50-200 Pa and 500-4000 Pa, respectively, were determined suitable for screen-printing application. In addition, these inks showed suitable viscosity and thixotropy with acceptable tackiness for screen-printing application. This range was exhibited by inks having binder and solids loading in the range of 1-3 wt% and 25-30 vol%, respectively. Furthermore, films fabricated using these inks showed improved particle connectivity, mechanical hardness, electrical and electrochemical performance resulting from increased particle connectivity.

CONFERENCE PAPER

Wu B, Yufit V, Merla Y, Martinez-Botas RF, Brandon NP, Offer GJet al., 2015, Differential thermal voltammetry for tracking of degradation in lithium-ion batteries, Journal of Power Sources, Vol: 273, Pages: 495-501, ISSN: 1873-2755

Monitoring of lithium-ion batteries is of critical importance in electric vehicle applications in order to manage the operational condition of the cells. Measurements on a vehicle often involve current, voltage and temperature which enable in-situ diagnostic techniques. This paper presents a novel diagnostic technique, termed differential thermal voltammetry, which is capable of monitoring the state of the battery using voltage and temperature measurements in galvanostatic operating modes. This tracks battery degradation through phase transitions, and the resulting entropic heat, occurring in the electrodes. Experiments to monitor battery degradation using the new technique are compared with a pseudo-2D cell model. Results show that the differential thermal voltammetry technique provides information comparable to that of slow rate cyclic voltammetry at shorter timescale and with load conditions easier to replicate in a vehicle.

JOURNAL ARTICLE

Boldrin P, Millan-Agorio M, Brandon NP, 2015, Effect of Sulfur- and Tar-Contaminated Syngas on Solid Oxide Fuel Cell Anode Materials, ENERGY & FUELS, Vol: 29, Pages: 442-446, ISSN: 0887-0624

JOURNAL ARTICLE

Boldrin P, Ruiz-Trejo E, Yu J, Gruar RI, Tighe CJ, Chang K-C, Ilavsky J, Darr JA, Brandon Net al., 2015, Nanoparticle scaffolds for syngas-fed solid oxide fuel cells, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 3, Pages: 3011-3018, ISSN: 2050-7488

JOURNAL ARTICLE

Cooper SJ, Li T, Bradley RS, Li K, Brandon NP, Kilner JAet al., 2015, Multi length-scale quantification of hierarchical microstructure in designed microtubular SOFC electrodes, Pages: 1857-1864, ISSN: 1938-5862

© The Electrochemical Society. The transport properties of a micro-tubular solid oxide fuel cell (MT-SOFC) anode have been analysed by imaging and simulation at multiple length-scales. The anode support investigated was manufactured using a phase inversion-assisted co-extrusion process, which generated a hierarchical and highly anisotropic microstructure. The resulting pore network was observed to contain two distinct, but interacting transport systems. The features in these systems spanned several orders of magnitude and as such it was not possible to image or model them simultaneously. The simulations indicated that the design of the microstructure was beneficial for the radial transport required by these cells; however this conclusion was only obtained by considering diffusive systems at many length-scales.

CONFERENCE PAPER

Tariq F, Kishimoto M, Cui G, Yufit V, Lomberg M, Ruiz-Trejo E, Chen Z, Brandon NPet al., 2015, Advanced 3D imaging and analysis of SOFC electrodes, Pages: 2067-2074, ISSN: 1938-5862

© The Electrochemical Society. An ability to meet our increasing energy demands will be facilitated though improving the next generation of electrochemical devices. The ability to directly image in 3D and analyse solid oxide fuel cell (SOFC) electrodes at high resolutions provides key insights in understanding structure-property relationships; as electrochemical reactions and transport phenomena are strongly affected by complex microstructure. Here we use tomographic techniques to probe 3D electrode structures at nanometer to micrometer length scales. In doing so the first characterisation of specific necks and interfaces alongside their particle sizes within SOFC electrodes is derived. Micro/nano structural changes are followed to facilitate understanding the differences which occur with shape, structures and morphology at high resolution. These are correlated with both measured experimental values and simulations to provide insight into microstructure-property relationships. We also demonstrate approaches to intelligently design electrodes through scaffolds, and potentially 3D printed structures, all towards optimising the structure for performance.

CONFERENCE PAPER

Kishimoto M, Lomberg M, Ruiz-Trejo E, Brandon NPet al., 2015, Towards the design-led optimization of solid oxide fuel cell electrodes, Pages: 2019-2028, ISSN: 1938-5862

© The Electrochemical Society. A one-dimensional numerical model of a nickel-infiltrated gadolinium-doped ceria (Ni-GDC) electrode has been developed to investigate the effects of electrode microstructure on performance. Electrode microstructural information was obtained with focused-ion beam tomography and microstructural parameters were quantified. These have been used to estimate the effective transport coefficients and the electrochemical reaction rate in the electrode. GDC was considered as a mixed ionic and electronic conductor and hence the electrochemical reaction was assumed to occur on the GDC-pore contact surface, i.e. double-phase boundaries (DPBs). Sensitivity analysis was conducted to investigate the effect of electrode microstructure on both transport properties and electrochemical activity. The developed model offers a basis to understand the electrode-microstructure relationships and to further optimize the electrode microstructures.

CONFERENCE PAPER

Cai Q, Adjiman CS, Brandon NP, 2014, Optimal control strategies for hydrogen production when coupling solid oxide electrolysers with intermittent renewable energies, JOURNAL OF POWER SOURCES, Vol: 268, Pages: 212-224, ISSN: 0378-7753

JOURNAL ARTICLE

Tariq F, Kishimoto M, Yufit V, Cui G, Somalu M, Brandon NPet al., 2014, 3D imaging and quantification of interfaces in SOFC anodes, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 34, Pages: 3755-3761, ISSN: 0955-2219

JOURNAL ARTICLE

Kishimoto M, Lomberg M, Ruiz-Trejo E, Brandon NPet al., 2014, Enhanced triple-phase boundary density in infiltrated electrodes for solid oxide fuel cells demonstrated by high-resolution tomography, JOURNAL OF POWER SOURCES, Vol: 266, Pages: 291-295, ISSN: 0378-7753

JOURNAL ARTICLE

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