Related Experiment Video
Updated: Jul 8, 2026
15:08
Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells
Published on: September 20, 2012
16.1K
Perspective on high-temperature surface oxygen exchange in a porous mixed ionic-electronic conductor for solid oxide
Hairui Han1, Yunan Jiang1,2, Shaowei Zhang1
1CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei, Anhui Province, 230026, P. R. China. xiacr@ustc.edu.cn.
Physical Chemistry Chemical Physics : PCCP
|May 2, 2023
Summary
Accurate measurement of the surface exchange coefficient (k) in porous mixed ionic-electronic conductors (MIECs) is crucial for solid oxide cells. This study reveals gas diffusion limitations in common methods, impacting oxygen reduction reaction kinetics.
Area of Science:
- Materials Science
- Electrochemistry
- Chemical Engineering
Background:
- The surface exchange coefficient (k) is critical for solid oxide cell performance.
- Existing measurement techniques (ECR, EIS, OIE) show discrepancies for porous MIECs.
- Understanding oxygen reduction reaction (ORR) kinetics in MIECs is essential.
Purpose of the Study:
- To analyze ORR mechanisms in porous MIECs.
- To identify limitations of ECR, EIS, and OIE methods.
- To investigate the impact of gas diffusion on ORR kinetics.
Main Methods:
- Comparative analysis of oxygen supply/consumption fluxes.
- Theoretical discussion of ECR, EIS, and OIE assumptions and limitations.
- Simulation and measurement of ECR profiles to assess gas diffusion effects.
Main Results:
- Discrepancies in 'k' values are attributed to method-specific issues.
- Gas diffusion significantly delays the ORR process in porous MIECs.
- Simulated ECR profiles highlight the influence of gas diffusion.
Conclusions:
- Current methods may not accurately reflect true ORR kinetics due to gas diffusion.
- A refined approach is needed to characterize ORR kinetics in porous electrodes.
- Quantifying gas diffusion effects is key for accurate performance prediction.
More Related Videos
Related Concept Videos
02:47Voltaic/Galvanic Cells
Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
01:06Interfacial Electrochemical Methods: Overview
Interfacial electrochemical methods focus on the phenomena occurring at the boundary between an electrode and a solution, as opposed to bulk methods that concentrate on the solution's overall properties. These interfacial methods are classified as either static or dynamic based on the presence of a nonzero current in the electrochemical cell and the consistency of analyte concentrations. Static methods, such as potentiometry, measure the cell's potential without any significant current passing...
01:24Electrochemical Systems
Electrochemical systems provide a fascinating insight into the dynamic interplay of charged species within various phases. One notable example is the interaction between a membrane permeable to K⁺ ions but not to Cl⁻ ions, separating an aqueous KCl solution from pure water. As K⁺ ions diffuse through the membrane, they generate net charges on each phase, leading to a potential difference between them.Similarly, when a piece of Zn is immersed in an aqueous ZnSO₄ solution, the Zn metal, composed...
01:28Electrochemical Cells
Electrochemical cells are systems that convert chemical energy into electrical energy or use electrical energy to drive chemical reactions. They consist of two electrodes in contact with an electrolyte, where redox reactions enable electron transfer. Most electrochemical cells include two half-cells connected by an external wire for electron flow and a salt bridge for ion flow. The salt bridge contains an electrolyte solution and maintains charge neutrality by allowing ions—not electrons—to...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
01:30Processes at Electrodes
The electrode interacts with ions in the electrolyte solution at its interface. The rate of oxidation and reduction depends on the speed at which electrons can transfer through this interface. As ions attach to or leave the electrode surface, the electrode acquires a charge, and an electrical potential forms across the interface, making the process more difficult to reach equilibrium. The charge on the electrode affects the local ion concentrations in the solution, though thermal motion...