Thin Film Electrolyte Research Articles

Effects of Oxygen Partial Pressure and Substrate Temperature on the Structure and Morphology of Sc and Y Co-Doped ZrO2 Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition.

Scandium (Sc) and yttrium (Y) co-doped ZrO2 (ScYSZ) thin films were prepared on a SiO2-Si substrate via pulsed laser deposition (PLD) method. In order to obtain good quality thin films with the desired microstructure, various oxygen partial pressures ( from 0.01 Pa to 10 Pa and substrate temperatures (Ts) from 25 °C to 800 °C were investigated. X-ray diffraction (XRD) patterns results showed that amorphous ScYSZ thin films were formed at room substrate temperature while cubic polycrystalline thin films were obtained at higher substrate temperatures (Ts = 200 °C, 400 °C, 600 °C, 800 °C). Raman spectra revealed a distinct Raman shift at around 600 cm−1 supporting a cubic phase. However, a transition from cubic to tetragonal phase can be observed with increasing oxygen partial pressure. Photoemission spectroscopy (PES) spectra suggested supporting analysis that more oxygen vacancies in the lattice can be observed for samples deposited at lower oxygen partial pressures resulting in a cubic structure with higher dopant cation binding energies as compared to the tetragonal structure observed at higher oxygen partial pressure. On the other hand, dense morphologies can be obtained at lower (0.01 Pa and 0.1 Pa) while more porous morphologies can be obtained at higher (1.0 Pa and 10 Pa).

Solid Oxide Fuel Cells with a Thin Film Electrolyte: A Review on Manufacturing Technologies and Electrochemical Characteristicses

Solid oxide fuel cells (SOFCs) are electrochemical systems converting the energy released during fuel oxidation into electrical energy. SOFCs are considered as a promising clean energy technology due to the high efficiency of fuel-to-power conversion and environmental friendliness. The potential applications of SOFCs extend from stationary power generation units for industrial and household facilities to auxiliary power units in vehicles and portable power sources. One of the main elements of SOFCs is a solid oxide electrolyte possessing ionic conductivity at high temperatures (above 700 °C). The main challenge in the SOFC commercialization is related to their high operating temperature, which entails materials degradation, short life-time, long start-up and shut-down times, and high cost. One of the most effective ways to reduce the SOFC operating temperature is to minimize the electrolyte thickness. In this regard, fabrication of SOFCs with a thin film electrolyte has been attracting high research activity over the past few decades. Different fabrication techniques were reported to be applicable for manufacturing thin film SOFCs, and the fuel cell performance was found to be highly dependent on the appropriate selection of materials and processing technologies. The present review is focused on state-of-the-art fabrication technologies of the thin film SOFCs. A brief survey of configurations and geometries of the thin film SOFCs and methods of deposition of solid-oxide films is given. Special attention is focused on the electrical generation performance of the thin film SOFCs.

A thin free-standing composite solid electrolyte film for solid-state lithium metal batteries.

A thin free-standing composite solid electrolyte film (CSE, ∼15 μm) is prepared by a tape casting and solution infusion method, which owns a high ionic conductivity (2.76 × 10-4 S cm-1 at 25 °C) and a wide electrochemical stability window (4.8 V vs. Li+/Li). The CSE-based solid-state lithium metal batteries with the LiCoO2 cathode present good cycling stability and capacity retention with a 4.5 V cut-off voltage.

Recipes for superior ionic conductivities in thin-film ceria-based electrolytes.

We employed Molecular Dynamics (MD) and Metropolis Monte Carlo (MMC) simulations to determine the oxide-ion mobility uO in Ce1-yGdyO2-y/2 (y = 0.02, 0.1, 0.2) for the range of temperatures 1400 ≤ T/K ≤ 2000 and field strengths 0.6 ≤ E/MV cm-1 ≤ 15.0. Direct, unambiguous determination of uO(E) from MD simulations is shown to require examination of the ions' mean displacement as a function of time. MD simulations were performed for random distributions of Gd cations and equilibrium distributions obtained by MMC calculations. All uO(E,T,y) data obtained can be described by an (empirically augmented) analytical model with four zero-field parameters, a result that allows data to be extrapolated down to the temperatures of electrolyte operation. Specifically, the oxide-ion conductivity is predicted, for example at T = 700 K, (i) to be up to 101 higher for a random distribution of Gd than for an equilibrium distribution; and (ii) to be a factor of 100.8 higher for a 6 nm thin film than for a μm-thick sample under a potential difference of 1 V. By virtue of non-equilibrium deposition and nm-thick samples, thin films thus provide two new recipes for attaining even higher oxide-ion conductivities in ceria-based electrolytes.

Improved Electrochemical Performance and Chemical Stability of Thin-Film Lithium Phosphorus Oxynitride Electrolyte by Appropriate Fluorine Plasma Treatment

Improved Electrochemical Performance and Chemical Stability of Thin-Film Lithium Phosphorus Oxynitride Electrolyte by Appropriate Fluorine Plasma Treatment

Nanoscale interface engineering for solid oxide fuel cells using atomic layer deposition.

Atomic layer deposition (ALD), which is already actively used in the semiconductor industry, has been in the spotlight in various energy fields, such as batteries and fuel cells, given its unique ability to enable the nanoscale deposition of diverse materials with a variety of compositions onto complex 3D structures. In particular, with regard to ceramic fuel cells, ALD has attracted attention because it facilitates the manufacturing of thin and dense electrolytes. Furthermore, recently, electrode surfaces and electrode/electrolyte interface modification are arising as new research strategies to fabricate robust fuel cells. In this mini-review, we present a brief overview of ALD and recent studies that utilize ALD in ceramic fuel cells, such as manufacturing thin film electrolytes, stabilizing electrodes, functionalizing electrodes, and modifying the chemistry of electrode surfaces. We also propose research directions to expand the utility and functionality of the ALD techniques.

Analytical analysis of concentration of charge carriers in polymer electrolytes through different models

The development of solid polymer electrolytes with high ionic conductivity and good chemical and mechanical stability for application in various electrochemical devices has been a critical area of research in the past few decades. For the better performance of the electrochemical devices, the compatibility between the electrodes and electrolytes of the system is the foremost requirement. In addition to this, the ion conductivity of the electrolytes is an important parameter. Understanding the mechanism of changes in ionic conductivity with different concentrations of salt and dispersoid is very crucial. In the present work, we have used three theoretical models, the Rice-Roth model, the Trukhan model and Schutt and Gerdes Model, to understand the reasons behind the variation in conductivity by calculating the concentration and mobility of charge carriers. All the required parameters of the model for the calculation purpose have been taken from Impedance Spectroscopy data. The Trukhan model is a direct method for evaluating the exact value of the diffusion coefficient. The diffusion coefficient of PEO-NaI based electrolyte thin films are calculated from the dielectric tangent loss and further used for analyzing the concentration of charge carrier and ion mobility. Similarly, two more theoretical models, Rice-Roth and Schutt & Gerdes model were used to confirm the value of the number of charge carriers. Further, all the results are compared with each other for the conclusion.

INVESTIGATION OF PMMA AND PVdF-HFP WITH NaClO4POLYMER BLEND ELECTROLYTE SYSTEM– APPLICATION TO AN ELECTROCHEMICAL CELL

A solution-cast process was used to prepare pure poly (methyl methacrylate) (PMMA), and pure poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), their blend, and different weight percentages of sodium per chlorate (NaClO4) salt added to PMMA: PVdF-HFP polymer blend electrolyte thin films. The polymer electrolyte film was prepared using the solution cast process, which involves combining sodium per chlorate (NaClO4) ionic slat with poly (methyl methacrylate) (PMMA) and pure poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) blended polymer. These films have been characterized systematically using different experimental techniques to investigate structural, morphological, thermal, and conductivity properties. The degree of crystallinity and porous microstructure of all the thin films were determined by XRD and SEM data and revealed that higher content of the amorphous nature was noticed at higher NaClO4 salt concentration in PMMA:PVdF-HFP polymer blend. When NaClO4 salt was added to a PMMA:PVdF-HFP polymer blend, fair complexation/interaction between polymers and salt was observed.In DSC curves of PMMA and PVdF-HFP polymers, a sharp melting temperature (Tm) was seen, which diminished when NaClO4 salt was added, showing that its amorphous nature had risen to prominence. The ionic conductivity of NaClO4 salt added PMMA:PVdF-HFP polymer blend electrolyte has been investigated, with an optimal value found to be1.55382 x 10-4S/cm at 40% NaClO4 salt. Electrochemical cells have been fabricated and investigated its characteristics in the configuration of Na/[PMMA:PVdF-HFP: NaClO4]/(I2:C).

Effect of EC plasticizer on Na+ ion based PMMA:PEO blend solid polymer electrolyte system

Solution casting method was used to prepare the Ethylene Carbonate (EC) doped in NaClO4 salt added PMMA:PEO blend polymer electrolyte thin films. Different characterization techniques such as XRD, SEM, DSC and FTIR were employed to study the effect on structural properties of these prepared thin films. The XRD, SEM and DSC results revealed the dominant presence of amorphous content in PMMA based polymer blend with the addition of PEO, NaClO4 and EC, which functions to enhance in ionic conductivity. FTIR spectra results elucidated that the vibrational band peaks corresponds to PMMA shifted towards lower or higher wave number side in presence of PEO, NaClO4 and EC, which confirms the interaction/complexation between PMMA, PEO polymers with NaClO4 salt and EC plasticizer.

Synthesis of Lithium Phosphorus Oxynitride (LiPON) Thin Films by Li3PO4 Anodic Evaporation in Nitrogen Plasma of a Low-Pressure Arc Discharge.

Thin amorphous films of LiPON solid electrolyte were prepared by anodic evaporation of lithium orthophosphate Li3PO4 in an arc discharge with a self-heating hollow cathode at a nitrogen pressure of 1 Pa. Distribution of the arc current between two electrodes having an anode potential provided independent control of the evaporation rate of Li3PO4 and the density of nitrogen plasma. Stabilization of the evaporation rate was achieved using a crucible with multi-aperture cover having floating potential. The existence of a threshold value of discharge current (40 A) has been established, which, upon reaching ionic conductivity over 10−8 S/cm, appears in the films. Probe diagnostics of discharge plasma were carried out. It has been shown that heating the films during deposition by plasma radiation to a temperature of 200 °C is not an impediment to achieving high ionic conductivity of the films. Dense uniform films of LiPON thickness 1 μm with ionic conductivity up to 1 × 10−6 S/cm at a deposition rate of 4 nm/min are obtained.

Enhancement of ionic conductivity in novel LiON-AlOx multilayer heterostructures prepared by atomic layer deposition

A novel heterostructured multilayer thin-film solid electrolyte consisting of LiON-AlOx was synthesized by atomic layer deposition (ALD). The ALD-derived films were grown about 200 °C on SiO2/Si substrate by an alternating deposition of lithium oxynitride (LiON) and AlOx sublayers with 1–6 nm thickness and then characterized by various methods for roughness, homogeneity, crystallinity, thickness, composition, chemical environment, and ionic conductivity. The desired layer-by-layer structure of the films was confirmed by both high-resolution transmission electron microscopy and time-of-flight secondary ion mass spectrometry. Compared to pure LiON films without insulating AlOx interlayers, the ionic conductivities of multilayer LiON-AlOx films with various nanoscale sublayers are enhanced due to channeling effects between the heterointerfaces of nanoscale sublayers, while the activation energies are increased due to the incorporation of non-conducting AlOx sublayers. Thickness-dependent conductivity of the multilayer LiON-AlOx films indicates that 3.2 nm of LiON sublayer alternatively combined with 1 nm AlOx sublayer has the best conduction performance. The film with 15 bilayers exhibits a conductivity of 6.2 × 10−4 S/cm at 160 °C with an activation energy of 0.57 eV.

Extended Condensed Ultraphosphate Frameworks with Monovalent Ions Combine Lithium Mobility with High Computed Electrochemical Stability.

Extended anionic frameworks based on condensation of polyhedral main group non-metal anions offer a wide range of structure types. Despite the widespread chemistry and earth abundance of phosphates and silicates, there are no reports of extended ultraphosphate anions with lithium. We describe the lithium ultraphosphates Li3P5O14 and Li4P6O17 based on extended layers and chains of phosphate, respectively. Li3P5O14 presents a complex structure containing infinite ultraphosphate layers with 12-membered rings that are stacked alternately with lithium polyhedral layers. Two distinct vacant tetrahedral sites were identified at the end of two distinct finite Li6O1626– chains. Li4P6O17 features a new type of loop-branched chain defined by six PO43– tetrahedra. The ionic conductivities and electrochemical properties of Li3P5O14 were examined by impedance spectroscopy combined with DC polarization, NMR spectroscopy, and galvanostatic plating/stripping measurements. The structure of Li3P5O14 enables three-dimensional lithium migration that affords the highest ionic conductivity (8.5(5) × 10–7 S cm–1 at room temperature for bulk), comparable to that of commercialized LiPON glass thin film electrolytes, and lowest activation energy (0.43(7) eV) among all reported ternary Li–P–O phases. Both new lithium ultraphosphates are predicted to have high thermodynamic stability against oxidation, especially Li3P5O14, which is predicted to be stable to 4.8 V, significantly higher than that of LiPON and other solid electrolytes. The condensed phosphate units defining these ultraphosphate structures offer a new route to optimize the interplay of conductivity and electrochemical stability required, for example, in cathode coatings for lithium ion batteries.

An accurate reduced-dimension numerical model for evolution of electrical potential and ionic concentration distributions in a nano-scale thin aqueous film

The numerical modelling of ionic diffusive transport through a charged thin film of electrolyte is mathematically and computationally complex due to the strongly coupled hydrodynamics and electrochemical interactions. Generally, simulations are performed by solving the Poisson equation together with the Nernst-Planck flux formula to model electrochemical processes in electro-diffusion problems. One important application of these system of equations to study the interaction of ionic diffusion and thin film hydrodynamics in petroleum engineering. However, due to the highly nonlinear and coupled equations the computational costs are heavy and very often limited to simulations in two-dimensional geometries. In this article, we have developed an equivalent one-dimensional electro-diffusive transport model based on mathematical averaging of 2D equations to reduce the computational time. Doing so, the computational time is improved substantially and simulation of much larger domain sizes which are required to study and interpret the experimental results is shown to be feasible. We have shown the high accuracy of the developed model by comparing the electric potential and concentration profiles of the developed model against the original 2D simulations. The developed approach reduces the computational effort by over 200 times without losing accuracy.

Investigation on the SCC behavior of ZL101A aluminum alloy in simulated marine environments

Stress corrosion cracking (SCC) behavior of ZL101A aluminum alloy in solution and thin electrolyte layer (TEL) with different pH was investigated in detail. The results indicated that the precipitated phases of ZL101A were composed of α-Al/Si eutectic crystal phase and Si–Mg–Fe precipitated phase, which accelerated the formation of corrosion pits. ZL101A presented the highest SCC susceptibility in pH = 4 solution compared with pH = 7 and 10 solutions, which was mainly attributed to the enhanced synergistic effect of anodic dissolution, stress and hydrogen embrittlement. The basically similar SCC susceptibilities in TEL environments were mainly controlled by the anodic dissolution, which was attributed to the high diffusion rate of O2 in the thin electrolyte film.

Electrochemical Behavior of Drawn Thin-Film Vitreous Lithium Metaphosphate

Lithium metaphosphate (LiPO3) thin-film glassy solid-state electrolyte (GSSE) ribbons with thicknesses varying from 35 to 800 μm have been drawn for the first time through softening and drawing of a cast and annealed preform of LiPO3 glass. The short-range order structure and composition of the thin-film glasses were confirmed to be identical to the bulk glass LiPO3 using Raman spectroscopy. Electrochemical impedance spectroscopy (EIS) was used to investigate the Li ionic conductivity of the thin-film GSSE samples and was essentially the same as that of the bulk LiPO3 glass. A model of area specific resistance (ASR) as a function of film thickness and temperature was generated and compared to resistances determined through equivalent circuit fitting of EIS generated Nyquist plots. The generated model compared well to the experimentally determined values. Symmetric cell cycling was conducted on the 50 μm thick samples to determine the cycling behavior and the durability of the electrolyte under applied voltage and sustained current. Evidence of the electrochemical stability of the LiPO3 thin-film GSSE against lithium metal was observed in the symmetric cell cycling as nearly perfectly flat and ohmic behavior cycling plateaus were found over a range of current densities. Prior to shorting, a critical current density of 65 μA/cm2 was obtained at 90 °C with a direct current (dc) Li ionic conductivity of 10–6.5 [Ω·cm]−1. While these current densities are low, this is the first report of a thin-film GSSE drawn into thicknesses of that required for high performance all-solid-state lithium batteries, and the proven stability and durability of this oxide GSSE is strong evidence that drawn thin-film GSSE materials, especially those with higher conductivities such as the well-studied sulfide glasses, are viable materials from which to create thin, easily processable solid-state electrolytes (SSEs) and warrant further research.

Exploring the structural uniformity and integrity of protonic ceramic thin film electrolyte using wet powder spraying

Thin protonic ceramic electrolyte contributes to lower ohmic resistance and enhances electrochemical performance of protonic ceramic electrochemical cells. However, manufacturing of large-scale thin electrolyte remains a challenge. Wet powder spraying is an attractive technique to deposit <10 μm thin electrolyte when advanced atomizing techniques and optimized spraying process are integrated. Here ultrasonic atomization is integrated in the wet powder spray technique to reduce the thickness of electrolyte. Moreover, a parametric study is conducted to optimize the wet powder spray process to deposit uniform and crack-free electrolyte film. It is illustrated that tuning of solid loading rates and spray passes can affect the morphology of the as-sprayed electrolyte film, enabling the structural compactness of the sintered electrolyte layer. To maintain chemical stability of the electrolyte layer during sintering, effect of sintering temperature is further investigated to produce a physically thin, structurally dense, and chemically homogeneous electrolyte layer. The protonic ceramic electrochemical cells fabricated with optimized spraying and sintering parameters demonstrate excellent performance under both fuel cell and electrolysis modes. In addition, the cells exhibit remarkable structural integrity during redox and long-term stability tests. • A wet powder spraying technique was integrated into the manufacturing of protonic ceramic electrochemical cells. • Solid loading rates, spray passes, and sintering temperatures were explored and optimized. • PCECs with a 7-μm thick BZCYYb electrolyte were successfully fabricated and demonstrated good structural uniformity and electrochemcial performance.

Isomeric Li–La–Zr–O Amorphous–Crystalline Composite Thin-Film Electrolytes for All-Solid-State Lithium Batteries

Isomeric Li–La–Zr–O Amorphous–Crystalline Composite Thin-Film Electrolytes for All-Solid-State Lithium Batteries

Aerosol Deposition of Thin-Film Single- and Bi-layered Solid Electrolytes for Intermediate Temperature Planar Solid Oxide Fuel Cells

One of the main limiting factors determining an increase in the specific power and efficiency of solid oxide fuel cells (SOFCs) is the development of deposition technique for thin-film gas-tight electrolytes. Hence, the development of inexpensive and scalable technologies to form thin-film electrolytes is the key direction of SOFC improvement. Despite existence of well-developed techniques, such as chemical vapor/solution deposition (CVD/CSD), electrochemical deposition (ED), thermal spray (TS), physical vapor deposition (PVD), all of them have a trend in rising deposition temperatures or establishing high vacuum that causes an increase in cost. The aerosol deposition (AD) also known as vacuum kinetic spraying (VKS) is a technique for deposition of thin and thick, gas-tight and porous layers. The deposition occurs due to the impact of high-energy particles to substrate and their consequent fragmentation and consolidation, this phenomenon is called room temperature impact consolidation (RTIC). The AD method is distinguished by the ability to lower the formation temperatures of a gas-tight electrolyte layer down to room temperatures by using a high-energy aerosol jet under conditions of low vacuum (1 – 1000 Pa) and room temperature. In addition, the method is characterized by low equipment cost and easy scaling. The possibility to deposit gas-tight films and films with controlled porosity in a wild range of thickness makes it possible to create all functional SOFCs layers without intermediate sintering steps. In the present work, the aerosol deposition technique was used to deposit thin-film electrolytes for anode-supported SOFCs. Two types of anode-supported SOFCs were manufactured. Type-1: thin-film electrolyte with the composition 8 mol.% yttria-stabilized zirconia (8YSZ) deposited on a bilayered anode substrate (current-collecting and functional sublayers) using the AD method followed by the screen-printing of a composite cathode with the composition of (La0.8Sr0.2)0.95MnO3-δ (LSM) and zirconia co-stabilized with 10 mol.% of scandia and 1 mol.% of yttria (10Sc1YSZ). Type-2: bilayered thin electrolyte made of 8YSZ and 10 mol% gadolinia doped ceria (GDC) protective layer deposited on a bilayered anode substrate using the AD method, followed by the screen printing of an active cathode with the composition of (La0.80Sr0.20)0.95CoO3–δ (LSC). The high quality of electrolyte layers of both types of SOFCs was confirmed by scanning electron microscopy, as well as electrochemical measurements, including the measurements of current-voltage characteristics and impedance spectroscopy. At 800 °C the anode-supported cells with humidified hydrogen as a fuel, and air as an oxidant demonstrated the open-circuit voltage of more than 1.04 V for both types of SOFCs, as well as specific power of more than 420 mW/cm2 and 780 mW/cm2 for type-1 and type-2 of SOFCs, respectively. Based on the studies carried out, further steps were determined to improve the electrochemical parameters of the cells, as well as to scale up to deposition on substrates with an area of 100x100 mm2.This work was carried out with financial support from the Russian Scientific Foundation, grant no. 17-79-30071. Figure 1

Metal Supported Proton Conducting Ceramic Cell with Thin Film Electrolyte for Electrolysis Application

Solid oxide fuel cells and electrolysis cells (SOC) have been comprehensively developed as energy conversion and storage devices in recent years. Compared with oxygen ion conducting SOC, proton-conducting ceramic (PCC) cells are more suitable for the operation in the temperature range of 450~650 oC. The reduced operating temperature makes it especially attractive for steam electrolysis application aiming at valorizing waste heat from industrial processes. Moreover, during electrolysis in PCC cells, by design, the water-splitting reaction occurs at the oxygen electrode which enables the production of pure hydrogen at the fuel electrode.Based on previous research on metal-supported solid oxide cells (MS-SOC)[1] at DLR, MS-PCC with thin film electrolyte were investigated in this present study. The low temperature fabrication route (< 1000 °C) was chosen to avoid the serious corrosion of metal substrate at high temperature (1300~1400 °C) which is necessary for making the dense BaZrO3 based electrolyte in traditional sintering routes. In this case, pulsed laser deposition has been used for preparing the 1~2 µm thick electrolyte. Porous ferritic stainless steel, which has been used as the substrate, was cut into a round shape of 18 mm in diameter. To mitigate the Cr diffusion from metal substrate and formation of impurity phase between the metal substrate and NiO/BaZrxCe0.9-xY0.1O3-δ (NiO-BZCY) anode functional layer during processing or operation, Sr-doped LaMnO3 (LSM) was employed as the barrier layer in between. Both LSM and NiO-BZCY layers were processed by lamination of tape-cast thin films onto the metal substrate respectively and successfully co-sintered below 1000 °C. The thermomechanical stability of the thin film electrolyte was investigated by simulating thermal cycles from room temperature up to 950 °C. Platinum and Ba1-xGd0.8La0.2+xCo2O6- δ [2] were considered as oxygen electrode materials. Electrochemical characterization was carried out in both fuel cell and electrolysis operations. Advantages and current limitations of the presented cell design are discussed.Part of this work was supported by the project DAICHI funded by EIG CONCERT-Japan. The German part was funded by the Federal Ministry of Education and Research (project 01DR18002), the Norwegian part funded by the Research Council of Norway (project 284289). The China Scholarship Council is acknowledged for the doctoral scholarship of Haoyu Zheng (201806160173).Figure.1 Scanning electron microscopy (SEM) image of the metal supported proton conducting cells.[1] Costa R., Han F., Szabo P., et al. Fuel Cells, 2018, 18 (3): 251-259.[2] Vøllestad E., Strandbakke R., Tarach M., et al. Nature Materials, Jul, 2019, 18 (7): 752-759. Figure 1

Redox Stability of Tubular Solid Oxide Cell Using LaGaO3 Electrolyte Film Prepared by Dip-Coating

Reversible operation of SOFC is now important subjects from energy storage of renewable electric power from solar or wind power. At present, planer type cell design is widely used for this purpose, however, because of tight gas sealing, tubular type cell design is more suitable. In this study, tubular solid oxide cell using La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) thin electrolyte film was prepared by dip-coating and co-sintering process. NiO-YSZ porous substrate with 10 mm diameter and 30 mm length was used for preparation of the cell. For preventing reaction between LSGM and NiO, TiO2-Ce0.6La0.4O2/Ce0.6Mn0.3Fe0.1O2 was used for buffer layer. The cyclic operation of fuel cell and electrolysis mode was measured for investigating the stability of the prepared tubular cell at an intermediate temperature of 600℃ under the fuel of 20%steam-30%H2 in Ar. After 100 redox cycles under the applied current density of ±100 mA cm-2 , OCV was almost the same with the initial value before measurement. The terminal potential in SOFC operation became slightly lower and unstable with increasing cycle number, however, degradation in power density is not significantly observed. The cell also presents a relative stable performance in the electrolysis mode and it seems to be more active to SOEC than that to SOFC. From measurement of internal resistance, degradation may be related with the increased overpotential of anode. Therefore, aggregation and reoxidation of Ni in Ni-YSZ substrate is expected.In order to further increase performance of the cell, effects of Ce infiltration into NiO-YSZ contributes and it was found that the power density and electrolysis performance was much increased by the decreased internal resistance. The redox stability of NiO-YSZ-CeO2 cell was also measured and it also presents a stable redox performance after 100 times cycles by infiltration of CeO2.