Imperial College London

Dr Paul Boldrin

Faculty of EngineeringDepartment of Earth Science & Engineering

Research Associate
 
 
 
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Contact

 

+44 (0)20 7594 9695p.boldrin

 
 
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Location

 

3.50Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

49 results found

Wehrle L, Wang Y, Boldrin P, Brandon NP, Deutschmann O, Banerjee Aet al., 2021, Optimizing Solid Oxide Fuel Cell Performance to Re-evaluate Its Role in the Mobility Sector, ACS Environmental Au, ISSN: 2694-2518

Journal article

Boldrin P, Malko D, Mehmood A, Kramm UI, Paul S, Weidler N, Kucernak Aet al., 2021, Deactivation, reactivation and super-activation of Fe-N/C oxygen reduction electrocatalysts: gas sorption, physical and electrochemical investigation using NO and O2, Applied Catalysis B: Environmental, Vol: 292, Pages: 1-12, ISSN: 0926-3373

We show that gaseous nitric oxide (NO) and oxygen (O2) are useful molecular probes to uncover complex surface processes in Fe-N/C catalysts. We unravel the difference between using gaseous NO in a temperature programmed desorption experiment and using NO (and progenitors) in an electrochemical experiment. Gas phase O2 adsorption is almost exclusively desorbed as CO2, and continued exposure to oxygen increases the amount of chemisorbed oxygen species on the surface. The oxidation state of the carbon surface is an important activity determining factor, and under normal “electrochemical” conditions many of the active sites are blocked. Only by treatment at 600 °C in Ar can we free those sites for oxygen adsorption, however under atmospheric storage, and especially during the oxygen reduction reaction (ORR), the surface quickly becomes deactivated with chemisorbed oxygen species and water. We demonstrate that the material can be super-activated by reductive electrochemical treatment, both in an electrochemical three electrode cell and in a fuel cell. The energy gained following the treatment is significantly larger than the energetic cost.

Journal article

Ouyang M, Bertei A, Cooper SJ, Wu Y, Boldrin P, Liu X, Kishimoto M, Wang H, Naylor Marlow M, Chen J, Chen X, Xia Y, Wu B, Brandon NPet al., 2021, Model-guided design of a high performance and durability Ni nanofiber/ceria matrix solid oxide fuel cell electrode, Journal of Energy Chemistry, Vol: 56, Pages: 98-112, ISSN: 2095-4956

Mixed ionic electronic conductors (MIECs) have attracted increasing attention as anode materials for solid oxide fuel cells (SOFCs) and they hold great promise for lowering the operation temperature of SOFCs. However, there has been a lack of understanding of the performance-limiting factors and guidelines for rational design of composite metal-MIEC electrodes. Using a newly-developed approach based on 3D-tomography and electrochemical impedance spectroscopy, here for the first time we quantify the contribution of the dual-phase boundary (DPB) relative to the three-phase boundary (TPB) reaction pathway on real MIEC electrodes. A new design strategy is developed for Ni/gadolinium doped ceria (CGO) electrodes (a typical MIEC electrode) based on the quantitative analyses and a novel Ni/CGO fiber–matrix structure is proposed and fabricated by combining electrospinning and tape-casting methods using commercial powders. With only 11.5 vol% nickel, the designer Ni/CGO fiber–matrix electrode shows 32% and 67% lower polarization resistance than a nano-Ni impregnated CGO scaffold electrode and conventional cermet electrode respectively. The results in this paper demonstrate quantitatively using real electrode structures that enhancing DPB and hydrogen kinetics are more efficient strategies to enhance electrode performance than simply increasing TPB.

Journal article

Chen J, Ouyang M, Boldrin P, Atkinson A, Brandon NPet al., 2020, Understanding the coarsening and degradation in a nanoscale nickel gadolinia-doped-ceria electrode for high-temperature applications., ACS Applied Materials and Interfaces, Vol: 12, Pages: 47564-47573, ISSN: 1944-8244

Nanostructure engineering is an effective approach to enhance the electrochemical performance of energy devices. While the high surface area of nanoparticles greatly enlarges the density of reaction sites, it often also leads to relatively rapid degradation as the particles tend to coarsen to reduce their high surface energy. Therefore, a nickel/gadolinia-doped-ceria (CGO) cermet electrode is studied, with a novel porous nanostructure consisting of nanoscale Ni (100 nm) and CGO (50 nm) crystallites, cosintered from nanocomposite precursor agglomerate particles. This electrode combines both high performance and excellent durability, with a total area-specific resistance (ASR) of 0.11 Ω cm2 at 800 °C and a stable ASR with up to 170 h ageing in humidified 5% H2-N2. Post-test analysis by 3D tomography shows that nickel coarsens and is responsible for the initial increase in ASR. However, the subsequent electrochemical performance is stable because reaction at the double phase boundaries (DPBs) on the surfaces of nanoscale CGO becomes dominant and is resistant to ageing. At this stage, the coarsened Ni network is also stabilized by the surrounding nanostructure. The dominant role of the DPB reaction is supported quantitatively using a continuum model with geometrical parameters obtained from 3D tomography.

Journal article

Chen J, Wang X, Boldrin P, Brandon NP, Atkinson Aet al., 2019, Hierarchical dual-porosity nanoscale nickel cermet electrode with high performance and stability, Nanoscale, Vol: 11, Pages: 17746-17758, ISSN: 2040-3364

Nano-structured metal-ceramic materials have attracted attention to improve performance in energy conversion applications. However, they have poor long-term stability at elevated temperatures due to coarsening of the metal nanoparticles. In this work we show that this can be mitigated by a novel design of the nano-structure of Ni cermet fuel electrodes for solid oxide cells. The strategy is to create a dual porosity microstructure, without the use of fugitive pore-formers, with micron-size pores to facilitate gas transport and nanoscale pores to control nano-particle coarsening. This has been achieved using a continuous hydrothermal synthesis and two-stage heat treatments to produce electrodes with micron size agglomerates of nano-structured porous Ni-Yttria-Stabilised-Zirconia (YSZ). This unique hierarchical microstructure combines enhanced electrochemical reaction in the high activity (triple phase boundary density 11 μm-2) nanoscale regions with faster gas diffusion in the micron-sized pores. The electrodes are aged at 800 °C in humidified 5% H2-N2 for up to 600 h. The electrochemical reaction resistance is initially 0.17 Ω cm2 but later reaches a steady long-term value of 0.15 Ω cm2. 3-D reconstruction of the electrodes after 10 h and 100 h of ageing reveals an increase in YSZ network connectivity and TPB percolation. This improvement is well-correlated to the 3-D tomography parameters using a physical model adapted from mixed conducting SOC air electrodes, which is also supported, for the first time, by numerical simulations of the microstructural evolution. These also reveal that in the long term, nickel coarsening is inhibited by the nanoscale entanglement of Ni and YSZ in the hierarchical microstructure.

Journal article

Boldrin P, Brandon NP, 2019, Progress and outlook for solid oxide fuel cells for transportation applications, Nature Catalysis, Vol: 2, Pages: 571-577, ISSN: 2520-1158

With their high temperatures and brittle ceramic components, solid oxide fuel cells (SOFCs) might not seem the obvious fit for a power source for transportation applications. However, over recent years, advances in materials and cell design have begun to mitigate these issues, leading to the advantages of SOFCs such as fuel flexibility and high efficiency being exploited in vehicles. Here, we review these advances, look at the vehicles that SOFCs have already been used in, discuss the areas that need improvement for full commercial breakthrough and the ways in which catalysis can assist with these. In particular, we identify lifetime and degradation, fuel flexibility, efficiency and power density as key aspects for SOFCs’ improvement. Expertise from the catalysis landscape, ranging from surface science and computational materials design, to improvements in reforming catalysts and reformer design, are instrumental to this goal.

Journal article

Chen J, Ouyang M, Boldrin P, Liu X, Darr J, Atkinson A, Brandon NPet al., 2019, Fabrication and Characterisation of Nanoscale Ni-CGO Electrode from Nano-Composite Powders, ECS Transactions, Vol: 91, Pages: 1799-1805, ISSN: 1938-6737

Journal article

Ouyang M, Boldrin P, Maher R, Chen X, Liu X, Cohen L, Brandon Net al., 2019, A mechanistic study of the interactions between methane and nickel supported on doped ceria, Applied Catalysis B: Environmental, Vol: 248, Pages: 332-340, ISSN: 0926-3373

A novel combined method using modified methane pulses and in-situ Raman spectroscopy together with mass spectrometry is applied to impregnated Ni/gadolinium-doped ceria (CGO). The partial oxidation of methane is deduced to proceed via a Mars-van-Krevelen type mechanism composed of initial methane decomposition together with carbon oxidation by oxygen from CGO. The critical role of the ceria surface and the bulk oxygen in the reaction is defined in detail. Oxygen is a necessary reactant in the reaction, as well as inhibiting carbon deposition. Oxygen spill-over is the driving force for the carbon oxidation and the ceria surface oxygen is resupplied by bulk oxygen after depletion. Bulk migration of oxygen to the surface is the rate-determining step. We also demonstrate that the ceria oxygen stoichiometry significantly affects the type of reaction and the rate of reaction between methane and Ni/CGO: The total oxidation of methane happens only when the oxygen stoichiometry is high while the oxygen spill-over rate decreases with decreasing oxygen stoichiometry, which reduces the rate of carbon elimination and results in reduction in the rate of methane oxidation. This work lays out a comprehensive evaluation methodology and provides important insights for future design of methane oxidation catalysts for solid oxide fuel cells, and more widely for methane reforming with different oxidants (steam, CO2, NO2 etc).

Journal article

Ouyang M, Bertei A, Cooper S, Wu Y, Liu X, Boldrin P, Kishimoto M, Wu B, Brandon Net al., 2019, Design of Fibre Ni/CGO Anode and Model Interpretation, 16th International Symposium on Solid Oxide Fuel Cells (SOFC-XVI)

Conference paper

Chen J, Ouyang M, Boldrin P, Liu X, Darr J, Atkinson A, Brandon Net al., 2019, Fabrication and Characterisation of Nanoscale Ni-CGO Electrode from Nano-Composite Powders, 16th International Symposium on Solid Oxide Fuel Cells (SOFC-XVI)

Conference paper

Ouyang M, Bertei A, Cooper SJ, Wu Y, Liu X, Boldrin P, Kishimoto M, Wu B, Brandon NPet al., 2019, Design of fibre Ni/CGO anode and model interpretation, ECS Transactions, Vol: 91, Pages: 1721-1739, ISSN: 1938-6737

A new structure of Ni/gadolinium-doped ceria (CGO) is prepared by a highly tuneable and facile combination of electrospinning and tape-casting method. The structure consists of a network made by continuous Ni fibres and filled in with CGO matrices. When used as the anode of solid oxide fuel cell (SOFC), though it has a lower triple phase boundary (TPB) density, it exhibits better performance compared with impregnated and cermet Ni/CGO with higher nickel loading. An algorithm is developed to determine the ceria-pore double phase boundary (DPB) density with different distance from nickel phase. Using the results, the relative electrochemical reaction rate on DPB and TPB of three different electrodes are calculated and proves that fibre-matrices structure has the morphology advantage of efficiently making use of all ceria-pore DPB. The relative contribution of DPB and TPB in anode reaction of SOFC is quantified in the first time and the importance of DPB is further stressed. This work provides new inspirations in material design of SOFC/SOEC and develops a novel strategy to evaluate the performance of electrodes quantitatively.

Journal article

Stevenson GR, Boldrin P, Brandon NP, 2019, Liquid-based synthesis of nickel- And lanthanum- co-doped strontium titanates for use as anodes in all-ceramic solid oxide fuel cell anodes, Pages: 1761-1770, ISSN: 1938-6737

Nickel- lanthanum- co-doped compositions of strontium titanate have been synthesized and characterized by a scaleable liquid-based synthesis that may offer an alternative to conventional solid-state synthesis. La0.52Sr0.28Ti0.94Ni0.06O3 is synthesized from soluble precursors followed by calcination in air. The materials can be made phase pure at temperatures as low as 1250°C, as highlighted by X-ray diffraction, and nickel exsolves in hydrogen in the same way as solid-state-synthesized materials. The particle size can be varied by calcination temperature and ball milling between 2 µm and 20 µm. The material is then measured electrochemically by electrochemical impedance spectroscopy and 4-point DC conductivity. A reduction in particle size from 20 µm to 9 µm results in a large improvement in impedance response measured.

Conference paper

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

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

Boldrin D, Boldrin P, Ruiz-Trejo E, Cohen LFet al., 2017, Recovery of the intrinsic thermoelectric properties of CaMn0.98Nb0.02O3 in 2-terminal geometry using Ag infiltration, Acta Materialia, Vol: 133, Pages: 68-72, ISSN: 1359-6454

Oxide based thermoelectric (TE) materials offer several advantages over currently used intermetallic alloys due to their chemical and thermal stability at high temperatures, non-toxic elements, low cost and ease of manufacture. However, incorporation of oxides into thermoelectric generators (TEGs) is hindered by factors such as the requirement for polycrystalline materials over single crystals and the large electrode/ceramic contact resistances. The latter significantly limits the performance efficiency of a working TEG. Here we report the TE properties of Ag infiltrated polycrystalline CaMn0.98Nb0.02O3 ceramics. We demonstrate that by using this route the intrinsic TE properties of this material are fully recovered in 2-terminal geometry through Ag infiltration, thereby overcoming the electrode TEG contact problem. This synthetic route provides opportunities for bridging the performance gap between the intrinsic TE and TEG device properties of oxides.

Journal article

Ouyang M, Boldrin P, Brandon NP, 2017, Methane Pulse Study on Nickel Impregnated Gadolinium Doped Ceria, 12th European SOFC & SOE Forum

Conference paper

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

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

Cassidy M, Neagu D, Savaniu C, Boldrin Pet al., 2017, New Materials for Improved Durability and Robustness in Solid Oxide Fuel Cell, Solid Oxide Fuel Cell Lifetime and Reliability: Critical Challenges in Fuel Cells, Pages: 193-216, ISBN: 9780081011027

This chapter provides an overview of the considerations that must be made regarding new materials development for improved durability and robustness in solid oxide fuel cells (SOFCs). A number of recent development concepts are outlined for the core cell materials of anode, electrolyte, and cathode, in particular new catalytic approaches such as catalyst impregnation and exsolution on the anode to improve redox and fuel flexibility and reduced temperature cathodes. Some of the challenges of scaling up into larger stacks are also discussed. Here the interactions of cell materials with stack materials, in particular the interconnect, are summarized, such as chromium poisoning and cell to interconnect electrical contact, both of which feature prominently in SOFC stack lifetime issues. Barriers to new materials development are outlined along with the potential for accelerated testing.

Book chapter

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

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

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

Jamil Z, Ruiz-Trejo E, Boldrin P, Brandon NPet al., 2016, Anode fabrication for solid oxide fuel cells: Electroless and electrodeposition of nickel and silver into doped ceria scaffolds, International Journal of Hydrogen Energy, Vol: 41, Pages: 9627-9637, ISSN: 1879-3487

A novel fabrication method using electroless and electrodeposited Ni/Ag/GDC for SOFC anodes is presented. First a porous Ce0.9Gd0.1O2−x (GDC) scaffold was deposited on a YSZ electrolyte by screen printing and sintering. The scaffold was then metallized with silver using Tollens' reaction, followed by electrodeposition of nickel from a Watt's bath. The electrodes (Ni/Ag/GDC) were tested in both symmetrical and fuel cell configurations. The microstructures of the Ni/Ag/GDC anodes were analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). Nano-particles of Ni formed in the porous GDC scaffold provided triple phase boundaries (TPB). The electronic conductivity of the Ni/Ag/GDC (3.5/24.7/71.8 vol%) electrode was good even at relatively low Ni volume fractions. The electrochemical performance was examined in different concentrations of humidified hydrogen (3% H2O) and over a range of temperatures (600–750 °C). The total area specific resistance (ASR) of the anode at 750 °C in humidified 97 vol% H2 was 1.12 Ω cm2, with low-frequency polarization (R_l) as the largest contributor. The electrodes were successfully integrated into a fuel cell and operated in both H2 and syngas.

Journal article

Gallagher JR, Boldrin P, Combes GB, Ozkaya D, Enache DI, Ellis PR, Kelly G, Claridge JB, Rosseinsky MJet al., 2016, The effect of Mg location on Co-Mg-Ru/γ-Al2O3 Fischer–Tropsch catalysts, Royal Society of London. Philosophical Transactions A. Mathematical, Physical and Engineering Sciences, Vol: 374, ISSN: 1364-503X

The effectiveness of Mg as a promoter of Co-Ru/γ-Al2O3 Fischer-Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of MgxAl2O3+x if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO3 phases. After subsequent Co-Ru impregnation MgxCo3-xO4 is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into MgxCo3-xO4. Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in MgxCo3-xO4. Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature.

Journal article

Millan M, Lorente E, Boldrin P, Brandon Net al., 2016, Integration of gasification and fuel cells: Interaction between the anode and contaminants in the syngas

Fouling due to carbon deposition on the fuel cell anode reduces the performance of the cell. • The addition of steam above S/C of 1 was found to reduce carbon deposition from tars but not fully suppress coke formation. • A combination of high S/C=ratio and current density may effectively inhibit carbon formation, maintaining cell performance. • Benzene and toluene represent a "worst-case scenario" as tar models and light fractions are more likely to produce carbon deposits.

Conference paper

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

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

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

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, Gallagher JR, Combes GB, Enache DI, James D, Ellis PR, Kelly G, Claridge JB, Rosseinsky MJet al., 2015, Proxy-based accelerated discovery of Fischer-Tropsch catalysts, CHEMICAL SCIENCE, Vol: 6, Pages: 935-944, ISSN: 2041-6520

Journal article

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