1
|
Bumberger AE, Nenning A, Fleig J. Transmission line revisited - the impedance of mixed ionic and electronic conductors. Phys Chem Chem Phys 2024; 26:15068-15089. [PMID: 38752774 DOI: 10.1039/d4cp00975d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
This contribution provides a comprehensive guide for evaluating the one-dimensional impedance response of dense mixed ionic and electronic conductors based on a physically derived transmission line model. While mass and charge transport through the bulk of a mixed conductor is always described by three fundamental parameters (chemical capacitance, ionic conductivity and electronic conductivity), it is the nature of the contact interfaces that largely determines the observed impedance response. Thus, to allow an intuitive adaptation of the transmission line model for any specific measurement situation, the physical meanings of terminal impedance elements at the ionic and electronic rail ends are explicitly discussed. By distinguishing between charge transfer terminals and electrochemical reaction terminals, the range of possible measurement configurations is categorized into symmetrical, SOFC-type and battery-type setups, all of which are explored on the basis of practical examples from the literature. Also, the transformation of an SOFC electrode into a battery electrode and the relevance of side reactions for the impedance of battery electrodes is discussed.
Collapse
Affiliation(s)
| | - Andreas Nenning
- Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria.
| | - Juergen Fleig
- Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria.
| |
Collapse
|
2
|
Williams NJ, Osborne C, Seymour ID, Bazant MZ, Skinner SJ. Application of finite Gaussian process distribution of relaxation times on SOFC electrodes. Electrochem commun 2023. [DOI: 10.1016/j.elecom.2023.107458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023] Open
|
3
|
Sciazko A, Komatsu Y, Yokoi R, Shimura T, Shikazono N. Effects of mass fraction of La0.9Sr0.1Cr0.5Mn0.5O3-δ and Gd0.1Ce0.9O2-δ composite anodes for nickel free solid oxide fuel cells. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2021.11.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
4
|
Sanna C, Squizzato E, Costamagna P, Holtappels P, Glisenti A. Electrochemical study of symmetrical intermediate temperature - solid oxide fuel cells based on La0.6Sr0.4MnO3 / Ce0.9Gd0.1O1.95 for operation in direct methane / air. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.139939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
5
|
Performance Investigation on Mono-Block-Layer Build Type Solid Oxide Fuel Cells with a Vertical Rib Design. ENERGIES 2022. [DOI: 10.3390/en15030979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Compared with planar-type solid oxide fuel cells (SOFCs), mono-block-layer build (MOLB)-type SOFCs have additional three-phase boundaries per unit volume, and their performance is severely limited by their longer current path. To resolve this issue, a vertical rib design, which was evaluated using a numerical method, was proposed. Compared with the conventional design, the power density for the vertical rib design increased by 12.32%. This is because the vertical rib design provides another short path for current, which not only reduces the ohmic loss in the cathode, but also decreases the ohmic polarization caused by the contact resistance. However, the vertical rib design hinders the transport of oxygen in the cathode and increases the concentration loss. Therefore, the vertical rib size design is crucial. Based on the influence of the vertical rib width, the vertical rib widths on the cathode and anode sides of 0.7 and 1 mm are recommended for different contact resistances, respectively.
Collapse
|
6
|
Riegraf M, Bombarda I, Dömling F, Liensdorf T, Sitzmann C, Langhof N, Schafföner S, Han F, Sata N, Geipel C, Walter C, Costa R. Enhancing the Mechanical Strength of Electrolyte-Supported Solid Oxide Cells with Thin and Dense Doped-Ceria Interlayers. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49879-49889. [PMID: 34643394 DOI: 10.1021/acsami.1c13899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The penetration of fuel cells and electrolyzers in energy systems calls for their scale-up to the gigawatt (GW) level. High temperature solid oxide cells (SOC) offer unrivaled efficiencies in both electrolysis and fuel cell operation. However, they are made of ceramics and are brittle by nature. Consequently, a high mechanical strength to avoid failure during stacking is essential to achieve a high manufacturing yield. Here, we show that without changing the materials of the state-of-the-art cells, thin and dense ceria interlayers enable comparable power densities and durability in fuel cell operation. The sole tuning of the morphology and processing of the interlayers reduce the residual stress in the cell significantly which increases its mechanical strength by up to 78%. These results promise performance gains of similar magnitude by enabling a substantial decrease of the electrolyte thickness while maintaining robustness. This stress engineering approach presents a way to increase the volumetric power density and material efficiency of SOC systems.
Collapse
Affiliation(s)
- Matthias Riegraf
- German Aerospace Centre (DLR), Institute of Engineering Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany
| | - Ilaria Bombarda
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Ferdinand Dömling
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Tom Liensdorf
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Carolin Sitzmann
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Nico Langhof
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Stefan Schafföner
- University of Bayreuth, Department of Ceramic Materials Engineering (CME), Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Feng Han
- German Aerospace Centre (DLR), Institute of Engineering Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany
| | - Noriko Sata
- German Aerospace Centre (DLR), Institute of Engineering Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany
| | | | | | - Rémi Costa
- German Aerospace Centre (DLR), Institute of Engineering Thermodynamics, Pfaffenwaldring 38-40, 70569 Stuttgart, Germany
| |
Collapse
|
7
|
Williams NJ, Seymour ID, Leah RT, Mukerjee S, Selby M, Skinner SJ. Theory of the electrostatic surface potential and intrinsic dipole moments at the mixed ionic electronic conductor (MIEC)-gas interface. Phys Chem Chem Phys 2021; 23:14569-14579. [PMID: 33988196 DOI: 10.1039/d1cp01639c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The local activation overpotential describes the electrostatic potential shift away from equilibrium at an electrode/electrolyte interface. This electrostatic potential is not entirely satisfactory for describing the reaction kinetics of a mixed ionic-electronic conducting (MIEC) solid-oxide cell (SOC) electrode where charge transfer occurs at the electrode-gas interface. Using the theory of the electrostatic potential at the MIEC-gas interface as an electrochemical driving force, charge transfer at the ceria-gas interface has been modelled based on the intrinsic dipole potential of the adsorbate. This model gives a physically meaningful reason for the enhancement in electrochemical activity of a MIEC electrode as the steam and hydrogen pressure is increased in both fuel cell and electrolysis modes. This model was validated against operando XPS data from previous literature to accurately predict the outer work function shift of thin film Sm0.2Ce0.8O1.9 in a H2/H2O atmosphere as a function of overpotential.
Collapse
Affiliation(s)
- Nicholas J Williams
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Ieuan D Seymour
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Robert T Leah
- Ceres Power Ltd, Viking House, Foundry Lane, Horsham, RH13 5PX, UK
| | | | - Mark Selby
- Ceres Power Ltd, Viking House, Foundry Lane, Horsham, RH13 5PX, UK
| | - Stephen J Skinner
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| |
Collapse
|