Solid Oxide Fuel Cell Anode Research Articles

A catalyst support for direct-ammonia solid-oxide fuel cell anodes based on lanthanum titanium oxynitride

Ammonia is considered a promising fuel for solid-oxide fuel cells (SOFCs) owing to its ease of transportation, hydrogen density, and energy content. Oxynitride supports are shown to improve the durability of YSZ-supported direct-ammonia SOFCs.

A Review of Electrochemical Cells with Geometrically Well-defined Interfaces for Solid Oxide Fuel Cell Anodes

A solid oxide fuel cell (SOFC) is a high-temperature (above 750℃) energy conversion device that generates electricity with high efficiency and low CO2 emission. It is essential to develop high-activity electrodes for its commercialization by lowering the operating temperature to below 700℃. Understanding the electrode reaction kinetics can provide fundamental insights for the rational design of high-performance electrodes. However, the three-dimensional porous microstructures of the SOFC electrodes make it difficult to analyze the reaction processes precisely. To overcome this issue associated with the conventional electrodes, the model electrodes with geometrically well-defined interfaces have been widely employed. In this paper, focusing on the SOFC anodes, the fabrication techniques, cell types, analysis tools, and the modeling studies in the literature will be reviewed.

Enhancing the Catalytic Activity and Coking Tolerance of the Perovskite Anode for Solid Oxide Fuel Cells through In Situ Exsolution of Co-Fe Nanoparticles

The in situ exsolved nanoparticles from the perovskite matrix have achieved increasing attention and wide applications in solid oxide fuel cells (SOFCs) due to their excellent stability and high catalytic activity. Herein, an A-site-deficient (Ba0.9La0.1)0.95Co0.7Fe0.2Nb0.1O3 – δ (BL95CFN) perovskite oxide with in situ exsolved Co-Fe nanoparticles is developed and investigated as an anode for SOFCs. Compared with stoichiometric BLCFN, a tiny A-site deficiency (5%) promoted the exsolution of cobalt and iron from the perovskite matrix of BL95CFN. This hybrid anode catalyst showed excellent electrochemical performance. The polarization resistance is 0.11 Ω cm2 for the BL95CFN anode at 750 °C, about 42% lower than that of the BLCFN anode. The maximum peak density (MPD) reaches 513.2 mW cm–2 at 750 °C for an electrolyte-supported single cell with the BL95CFN anode. The high electrochemical performance could be attributed to the accelerated hydrogen surface exchange process provided by exsolved Co-Fe nanoparticles and oxygen ion transport in the A-site-deficient perovskite matrix. High-resolution transmission electron microscope (HRTEM) reveals that exsolved Co-Fe nanoparticles are embedded in the oxide matrix, forming a firm anchoring structure, which ensures excellent anode coking tolerance. At the current density of 200 mA cm–2, the output voltage of the single cell remained stable within 200 h in methane fuel. Overall, the high catalytic activity and coking tolerance of the hybrid electrocatalyst manifest a bright prospect of application in SOFCs and electrolytic cells.

Investigating realistic anode off-gas combustion in SOFC/ICE hybrid systems: mini review and experimental evaluation

Solid oxide fuel cells (SOFCs) have been deployed in hybrid decentralized energy systems, in which they are directly coupled to internal combustion engines (ICEs). Prior research indicated that the anode tailgas exiting the SOFC stack should be additionally exploited due to its high energy value, with typical ICE operation favoring hybridization due to matching thermodynamic conditions during operation. Consequently, extensive research has been performed, in which engines are positioned downstream the SOFC subsystem, operating in several modes of combustion, with the most prevalent being homogeneous compression ignition (HCCI) and spark ignition (SI). Experiments were performed in a 3-cylinder ICE operating in the latter modus operandi, where the anode tailgas was assimilated by mixing syngas (H2: 33.9%, CO: 15.6%, CO2: 50.5%) with three different water vapor flowrates in the engine’s intake. While increased vapor content significantly undermined engine performance, brake thermal efficiency (BTE) surpassed 34% in the best case scenario, which outperformed the majority of engines operating under similar operating conditions, as determined from the conducted literature review. Nevertheless, the best performing application was identified operating under HCCI, in which diesel reformates assimilating SOFC anode tailgas, fueled a heavy duty ICE (17:1), and gross indicated thermal efficiency ([Formula: see text]) of 48.8% was achieved, with the same engine exhibiting identical performance when operating in reactivity-controlled compression ignition (RCCI). Overall, emissions in terms of NOx and CO were minimal, especially in SI engines, while unburned hydrocarbons (UHC) were non-existent due to the absence of hydrocarbons in the assessed reformates.

Electrochemical performance and redox stability of solid oxide fuel cells supported on dual-layered anodes of Ni-YSZ cermet and Ni–Fe alloy

A Ni–Fe alloy layer in combination with a cermet layer composed of Ni and yttria-stabilized zirconia (YSZ) cermet layer was explored as an anode for solid oxide fuel cells (SOFCs). The cell supported on the dual-layered anode with straight pore paths showed a maximum power density of 1070 mW cm−2 at 800 °C, while 737 mW cm−2 for the one supported on the anode with tortuous pore paths. Electrochemical impedance measurement and distribution of relaxation time analysis revealed that the straight pore paths allowed fast gas phase transport thus mitigating the concentration polarization, and improved the accessibility of electrochemical reaction sites hence reducing the activation polarization. The cell supported on the Ni-YSZ/Ni–Fe dual-layered anode remained intact after 8 redox cycles, whereas the cell supported on the Ni-YSZ single layered anode failed after one redox cycle. It is concluded that the Ni-YSZ/Ni–Fe dual-layered composite explored in the present study is suitable for use as the supporting anode for SOFCs.

Understanding the oxygen-vacancy-related catalytic cycle for H2 oxidation on ceria-based SOFC anode and the promotion effect of lanthanide doping from theoretical perspectives

Lanthanide-doped ceria is known to be a promising solid-oxide-fuel-cell (SOFC) anode material. Understanding the catalytic cycle of fuel oxidation reaction on lanthanide-doped ceria is of great significance for the design of CeO2-based anode materials and catalytic processes with improved activity. Herein, we performed density functional theory (DFT) calculations on pure and Pr-, Nd-, Sm-, Gd-doped CeO2(111) to investigate the catalytic cycle of oxygen vacancy (Ov) generation and recovery in H2 oxidation process. Lanthanide doping promotes H2 dissociation, H2O formation, H2O desorption, and bulk O2− diffusion steps in the catalytic cycle. On the basis of thermodynamic and kinetic analysis, we propose that under anodic SOFC conditions, there is not a single stable Ov on pure, Pr-, Nd-, and Sm-doped surfaces because the first nearest-neighbor Ov is filled immediately upon formation, followed by the next catalytic cycle, while one Ov exists stably on Gd-doped surface, and subsequent catalytic cycle proceeds on the second nearest-neighbor vacancy site. The presence of a single Ov reduces the catalytic activity for H2 oxidation reactions on Gd-doped surface. Sm-doped ceria showed the best promotion effect for the whole Ov-related catalytic cycle, in agreement with the experimental observations.

Cycling Characteristics of Tubular Liquid Antimony Anode Solid Oxide Fuel Cells Prepared by Atmospheric Plasma Spraying

Liquid antimony anode solid oxide fuel cell (LAA-SOFC) is a promising technology for efficient conversion of solid carbon and hydrocarbon fuels. However, the operating process and the regeneration method of the fuel cells with LAAs are different from those with solid anodes and still need to be investigated. In the present research, a tubular LAA-SOFC unit was fabricated by atmospheric plasma spraying based on a stainless-steel support. The LAA-SOFC was cycled by a furnace control method and a “hot plug” method to simulate the normal start-stop and the anode/cell replacement processes, respectively. Scarce degradation was observed after the cycles with phase change, redox and temperature variation, which demonstrated the robustness of the sprayed electrolyte to the anode changes. The air leakage and the floating ash retarded the recovery rate of the “hot plug” cycles, but have no influence on the degradation degree. The cycling characteristics in the present research proved the long-term operating feasibility of SOFC with LAA.

Quantifying Percolated Triple Phase Boundary Density and Its Effects on Anodic Polarization in Ni-Infiltrated Ni/YSZ SOFC Anodes

Increasing the density of percolated triple phase boundaries (TPBs) by infiltrating nanoscale electrocatalysts can improve the performance of solid oxide fuel cell (SOFC) anodes. However, the complex microstructure of these infiltrated nanocatalysts creates challenges in quantifying their role in anode performance improvements. In this research, scanning electron microscopy of fractured cross-sections of a Ni-nanocatalyst infiltrated anodic symmetric cell along with three-dimensional (3-D) reconstruction of the same anode have been used to quantify the changes in percolated TPB densities due to infiltration. This change in percolated TPB density has been compared to the improvement in anode activation polarization resistance measured by electrochemical impedance spectroscopy (EIS). It was found that increased TPB densities only partially accounted for the measured performance improvement. Distribution of relaxation times (DRT) analyses showed that a reduction in the time constants of the catalytic processes in the anode also play a role, suggesting that the added nanoscale percolated TPB boundaries are more electrochemically active as compared to the cermet TPB boundaries.

Understanding the Impact of Sulfur Poisoning on the Methane-Reforming Activity of a Solid Oxide Fuel Cell Anode

Understanding the Impact of Sulfur Poisoning on the Methane-Reforming Activity of a Solid Oxide Fuel Cell Anode

Investigating the Solid Oxide Fuel Cell Anode Degradation Under Siloxane Contamination

Siloxane, a typical contaminant component in biogas from wastewater treatment plants and landfills, can negatively affect prime movers such as solid oxide fuel cells (SOFCs) and engines due to its deposition. In order to investigate the solid oxide fuel cell nickel-yttria stabilized zirconia (Ni-YSZ) anode degradation mechanism because of siloxane contamination, three different experimental methods were conducted. First, fuels with different components were utilized for SOFCs with ppmv level siloxane. The degradation rates among different experiments were analyzed and compared to assess the influence of reactants on the siloxane degradation process. Then, Pure YSZ and Ni pellets were utilized to investigate their roles in siloxane deposition process individually. The pellet experiments can also reduce the complexity of deposition composition analysis by various techniques used in this study such as scanning electron microscopy, wavelength-dispersive X-Ray spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy and Raman spectroscopy. Acceleration degradation experiments for SOFCs were accomplished with percentage level siloxane contamination. In this case, the exhaust gas for the siloxane deposition process was analyzed by gas chromatography (GC) for gas phase product identification. After considering the experimental results from the three methods mentioned before, a new anode degradation mechanism is proposed. The chemical adsorption process of siloxanes on the anode is hypothesized as an essential process in deposition reactions. Beside silicon deposition, carbon deposition is also assessed in this study, and it is also considered to play a critical role in SOFCs’ degradation process.

The prediction of the polarization curves of a solid oxide fuel cell anode with an artificial neural network supported numerical simulation

The presented study focuses on a numerical simulation of the transport phenomena inside a solid oxide fuel cell anode. The classical mathematical model leads to a notable discrepancy between measured and predicted overpotentials. One of the possible reasons is the assumption of the constant values of electrochemical reaction charge transfer coefficients. A modified formulation of the problem includes data-driven correction of reaction charge transfer coefficients in the electrochemical reaction model. Here we show a dedicated computational scheme in which an artificial neural network updates the charge transfer coefficients depending on the operational conditions and the available datasets. The neural network was trained on twelve experimental data points of an anode's polarization curve obtained from the literature. The training set contained data for the anode operating in two different temperatures - 800 °C and 900 °C. The test set contained additional six data points for an anode operating at 1000 °C. Charge transfer coefficients were proposed by the Artificial Neural Network as a functional relation of the temperature and withdrawn current. The results of the predictions are juxtaposed with the experimental data from the literature. It was shown that an Artificial Neural Network could improve an electrochemical reaction model in Solid Oxide Fuel Cell modeling.

Enhancing Ni Exsolution by Nonmetal B-Site Substituents (Si and P) in SrTiO3-Based Solid Oxide Fuel Cell Anodes

Enhancing Ni Exsolution by Nonmetal B-Site Substituents (Si and P) in SrTiO₃-Based Solid Oxide Fuel Cell Anodes

Catalyst-Exsolving Anode-Supported Low-Temperature Solid Oxide Fuel Cell

While ceramic anodes provide a path to overcome the obstacles of the current state of the art cermet-based solid oxide fuel cells (SOFCs), they are limited by processing challenges, low conductivity, poor catalytic activity, and instability. Here, we address these challenges by fabricating a ceramic-anode-supported SOFC composed of Sr2Fe0.4Ni0.8Mo0.8O6−δ (SFNM) which is highly conductive and spontaneously exsolves nano-catalysts for low temperature operation (600 °C). Using a simple and scalable procedure, we manufacture these SOFCs to have 60% lower ohmic loss than their electrolyte-supported analogues and we take advantage of the in-situ catalyst exsolution to circumvent additional catalyst deposition steps. We show that the catalyst exsolution triples the peak power density up to ∼200 mW cm−2 at 600 °C with H2 fuel, which is comparable to other ceramic anode SOFCs operating at considerably higher temperatures (>700 °C). Further, we discuss two major challenges facing exsolution-anode supported SOFCs, show our efforts to identify and address the root causes of such problems, and describe a potential path forward for next-generation anodes.

Mathematical approaches to modelling the mass transfer process in solid oxide fuel cell anode

In the recent literature, the influence of lean fuel, type of fuel, velocity profile and the flow direction on the performance operation of solid oxide cells (SOCs) is commonly investigated. SOCs generate electricity when they operate in fuel cell mode (SOFC – Solid Oxide Fuel Cell) or produce hydrogen in electrolysis mode (SOEC – Solid Oxide Electrolyzer Cell). They consist of several layers, including two porous electrodes separated by a gas-tight electrolyte. Typical anode porosity (fuel electrode in SOFC mode) varies from 20% to 50% (after sintering). The porosity value may limit the mass transport and the overall performance of SOC. This work investigates computationally and experimentally, the existing challenge such as diffusion mechanism in porous medium using the example of SOC electrode. A set of mass transport models (Fick's laws, modified Fick's law, Maxwell-Stefan Model, Dusty Gas Model) are described and discussed, highlighting their similarities, differences, advantages, and disadvantages as well as restrictions in usage. Finally, a detailed computational fluid dynamics (CFD) model of the diffusive transport in porous electrode was elaborated and validated. An experimental campaign was conducted using anode supported SOC, fabricated at the Institute of Power Engineering in Poland. Simulations were performed of the mass transport of pure hydrogen and pure water vapor or carbon dioxide (substitute of real product of electrochemical reaction in SOC for validation purposes) through porous anode. Tests were conducted in the wide flow range 10 [ml/min] up to 200 [ml/min] for both gases. The results demonstrate that hydrogen mole fractions reached similar values (0.5–0.6) at both outlets only for the maximum residence time or high porosity of anode. This implies that residence time and gas diffusion can be controlled by a combination of operating and microstructural parameters and can be estimated by numerical simulation using computational fluid dynamics. The main motivation and outcome of this work were to reduce the cost and time required for the optimization of the mass transport process through SOC's porous electrode.

Synthesis of Co–Ni and Cu–Ni based-catalysts for dry reforming of methane as potential components for SOFC anodes

In this work, we report a comparative study of Ni-based anode compositions, made of Cu and Co (40 and 80 mol%) and gadolinia-doped ceria (CGO) matrices, for application the dry reforming of methane (DRM) reaction using Solid Oxide Fuel Cells (SOFCs). The new compositions are synthesized by a one-step synthesis route, using citric acid as chelating agent, and characterized at three different stages: i) after synthesis, ii) after reduction, and iii) after DRM. X-ray diffraction (XRD) analysis combined with thermodynamic calculations is used to understand phase evolution along the different stages, revealing that complete solid solutions of NiCo- and NiCu-based alloys are formed after DRM reaction. Transmission Electron Microscopy (TEM) shows the formation of nanocrystalline powders, while surface area (SBET) measurements show higher values in the case of the NiCo-based samples. Moreover, the Co-containing compositions exhibit higher reducibility and stronger metal-ceramic interactions than the Cu-containing samples, according to the Temperature Programmed Reduction (TPR) results. Finally, DRM results demonstrate higher CO2 and CH4 conversions in the case of the Co-containing samples, as well as increased resistance towards carbon deposition, as confirmed by Thermogravimetric and Differential Scanning Calorimetry analyses (TG-DSC). Overall, the Co-based compositions are highly beneficial for their use as anodes for the CO2 reforming of methane in SOFCs.

In-situ exsolution of Ni nanoparticles to achieve an active and stable solid oxide fuel cell anode catalyst on A-site deficient La0.4Sr0.4Ti0.94Ni0.06O3-δ

(La,Sr)TiO3 has been investigated as a promising anode material for solid oxide fuel cells (SOFCs) owing to its high electronic conductivity and superior phase stability. However, the low catalytic activity of (La,Sr)TiO3 materials is a major obstacle to the application of SOFCs. Exsolution has emerged as an effective strategy to overcome the low catalytic activity of (La,Sr)TiO3 materials. In this work, Ni-doped A-site-deficient La0.4Sr0.4TiO3-δ (LST) (i.e., La0.4Sr0.4Ti0.94Ni0.06O3-δ; LSTN) with in-situ exsolved Ni nanoparticles (NPs) was developed and the effects of exsolved Ni NPs on H2 oxidation was investigated. The doped Ni was exsolved and formed NPs on the LSTN surface under reducing conditions. Owing to the high catalytic activity of the exsolved Ni NPs, the SOFC with LSTN-Ce0.9Gd0.1O2-δ (GDC) yielded a maximum power density of 0.46 W cm−2 at 850°C, 91% higher than that of the cell with LST-GDC, as well as high long-term and redox stability. Furthermore, density functional theory calculations revealed that the adsorption and dissociation of H2 were more favorable for exsolved Ni NPs than for pure Ni owing to the more positively charged surface of the exsolved Ni NPs in the LSTN. These results demonstrated that exsolution is an effective method for improving the electrocatalytic activity of perovskite (La,Sr)TiO3 materials.

A-Asterisk Algorithm as an Alternative to Evaluate the Geometric Tortuosity in Digitally Created SOFC Anodes

A solid oxide fuel cell (SOFC) is an electrochemical device that convert the chemical energy present in reactant gases, usually any chemical compound with hydrogen as constitutive element, into electrical energy and heat. The energy conversion process occurs at a high temperature and in a noiseless manner. As a result, the efficiency is relatively high, especially if the co-generation is considered. Diffusion processes within the SOFC porous media plays an important role since the reactant gases have to reach the three-phase boundary to perform the energy conversion process. An in-depth analysis of the microstructural configuration offers an increased understanding of the reactant flow.This paper aims to evaluate the feasibility of using the A-asterisk algorithm to compute the geometric tortuosity within SOFC anodes. A three-dimensional structure, which is digitally created, represents the SOFC anode, in which the possible paths that follow the fluid flow are analyzed. A-asterisk algorithm is used to generate possible paths, and therefore the geometric tortuosity can be computed considering an averaged distance. A tortuosity-porosity correlation is proposed, and the results are compared with previous studies. Results show that the A-asterisk algorithm is a capable algorithm to evaluate the geometric tortuosity values in SOFC anodes with different particle size distribution and porosities.

Electrical Properties of Novel La0. 2Sr0.7-xCaxTi0.95Fe0.05O3-δ Based Fuel Electrode for Solid Oxide Cell

As the fuel electrode is a central component of solid oxide fuel cell (SOFCs), evaluation of novel fuel electrode materials for SOFCs has become a favorite research subject. Perovskite structure offers an excellent framework for altering the chemical and physical properties of a material due to its ability to accommodate many different cations. In the present research novel La0.2Sr0.7-xCaxTi0.3Fe0.7O3-δ (LSCFT) fuel electrode compositions have been synthesized by glycine-nitrate reaction for high-temperature solid oxide fuel cell application. For analysis of the influence of Sr/Ca ratio on the electrical conductivities of different compositions of LSCFT, the DC four-probe conductivity measurement method has been performed. Conductivities have been measured at three different atmospheres: synthetic air; 97% H2 + 3% H2O and in 1%H2 + 3% H2O + 96% Ar. The crystal structure and microstructure have been studied using X-ray diffraction and SEM, respectively to confirm the purity of phase and percentage of porosity.In previous studies by Irvine et al. [1] has been demonstrated the effect of calcium doping on A-site deficient lanthanum strontium titanate, which displayed enhancement of its electrical conductivity and maximum conductivity was observed for La0.20Sr0.25Ca0.45TiO3 (LSCT) composition. Moreover, the same composition was tested and it confirmed as an active fuel electrode in fuel cell conditions, where good performance was achieved [2].Keywords: Fuel electrode, Electrical conductivity, Layered Perovskite, MIEC material, high temperature SOFC.[1] Aljaberi AD, Irvine JTS. Ca-substituted, A-site deficient perovskite La0.2Sr0.7TiO3 as a potential anode material for SOFCs. J Mater Chem A 1 (2013) 5868-74.[2] Verbraeken MC, Iwanschitz B, Mai A, Irvine JTS. Evaluation of Ca doped La0.2Sr0.7TiO3 as an alternative material for use in SOFC anodes. J Electrochem Soc 159 (2012) F757-62.

Aqueous Thick-Film Ceramic Processing of Planar Solid Oxide Fuel Cells Using La0.20Sr0.25Ca0.45TiO3 Anode Supports

Research into the use of Rh and Ce0.80Gd0.20O1.90 (CGO20) co-impregnated La0.20Sr0.25Ca0.45TiO3 (LSCTA-) anodes for electrolyte-supported Solid Oxide Fuel Cells (SOFC) has yielded extremely impressive durability and robustness at industrial short stack scales over the past decade. These anodes have exhibited the ability to rival the degradation and RedOx/thermal/thermo-RedOx cycling tolerance of state-of-the-art SOFC anodes at short stack scales, in addition to providing the ability to operate under sulfur-laden fuel gas streams and high fuel utilisation/overload conditions. (1)Given the success of implementation of LSCTA- anodes into Electrolyte Supported Cells (ESC) and the reasonable mechanical strength of LSCTA- as a support material, (2,3) successful attempts have also been made to employ LSCTA- as an anode support for SOFC at button cell scales, (4,5) in addition to appraisal of the upscaling of thick-film ceramic processing techniques used to prepare larger (20 cm by 20 cm) SOFC anode supports. (3) These studies performed by Lu et al., Ni et al. and Verbraeken et al. (3-5) focussed upon production of LSCTA- anode supports by aqueous tape casting followed by either co-casting or screen printing of a 8 mol. % yttria-stabilised-zirconia (8YSZ) electrolyte layer.Therefore, using these studies as a basis for the current research, we present results concerning the ceramic processing of Anode Supported Cells (ASC) that employ LSCTA- anode ‘backbone’ microstructures, with the ultimate aim of testing SOFC whose anodes have been decorated with Rh and CGO20 catalysts through wet impregnation. Here, we detail a thermal compatibility study of a variety of electrode and electrolyte material sets using dilatometric analysis, leading to the conclusion that the shrinkages of LSCTA- and 8YSZ are sufficiently matched to allow co-sintering of the anode support and electrolyte layers. Subsequently, the thick-film aqueous ceramic processing of LSCTA- anode supports, via tape casting, is discussed in addition to an appraisal of the most appropriate method to produce dense 8YSZ electrolyte layers (i.e., electrolyte deposition by co-casting or screen printing), with the aim of co-sintering the structure up to 1400 °C in air. Finally, an evaluation of the microstructural characteristics of LSCTA − supports, prepared using a typical graphite pore former (commonly used with organic solvent systems) or without the use of a pore former, will be provided, in comparison to microstructures resulting from the incorporation of poly(ethyl/methyl methacrylate) pore formers that are compatible with the aqueous solvent system employed. References R. Price, M. Cassidy, J. G. Grolig, G. Longo, U. Weissen, A. Mai and J. T. S. Irvine, Adv. Energy Mater., 2003951, 1 (2021).V. Vasechko, M. Ziegner and J. Malzbender, Ceram. Int., 40, 13179 (2014).M. C. Verbraeken, B. R. Sudireddy, V. Vasechko, M. Cassidy, T. Ramos, J. Malzbender, P. Holtappels and J. T. S. Irvine, J. Eur. Ceram. Soc., 38, 1663 (2018).L. Lu, C. Ni, M. Cassidy and J. T. S. Irvine, J. Mater. Chem. A, 4, 11708 (2016).C. Ni, L. Lu, D. N. Miller, M. Cassidy and J. T. S. Irvine, J. Mater. Chem. A, 6, 5398 (2018).

First-Principles Calculation and Multi-Scale Observation for a Carbon Deposition on a SOFC Anode Near the Interface

The nickel/yttria-stabilized zirconia (Ni/YSZ) and nickel/scandia-stabilized zirconia (Ni/ScSZ) have widely used as an anode for solid oxide fuel cells (SOFCs). The high operation temperature allows an SOFC to operate on a wide range of fuels, including hydrocarbons and coal syngas. Ni is also a catalyst for carbon deposition reactions which destroy the anode microstructure. Meanwhile, the carbon deposited on the electrode can be used for different ways. It is important to control the carbon deposition on the electrode; therefore, the carbon deposition model needs to be developed.In this study, carbon deposition site in the Ni/YSZ and Ni/ScSZ was studied through first-principles calculation and multi-scale observation using SEM and TEM. Observation showed that the carbon deposition was progressed not in the overall Ni surface but in the specific sites such as the interfaces and Ni(211) facet at low temperature. The carbon deposition rate strongly depended on the electrode structure at microscales. All calculations here are performed employing the periodic density functional theory (DFT) method implemented in the Vienna Ab-Initio Simulation Package (VASP). The Ni/YSZ and Ni/ScSZ atomic models are developed to discuss the CH adsorption which is the initial step of the carbon deposition. The CH adsorption energy in the concentrated vacancies at the Ni/YSZ interface was much lower than that in the Ni(111) facet, indicating that concentrated vacancies become the active site of the carbon deposition. However, the CH adsorption energy in the dispersed vacancies are almost the same as that in the Ni(111) facet. It is shown that vacancy patterns play an important role in the carbon deposition rate. The impact of dopant in the anode on the carbon deposition is also studied. DFT calculation gives an useful hint to develop the carbon deposition model with considering the electrode structure.