Wet Infiltration Research Articles

Novel approach to roof rainwater harvesting and aquifer recharge in an urban environment: Dry and wet infiltration wells comparison

In urban environments there is a severe reduction of infiltration and groundwater recharge due to the existence of large impervious areas. During rain events, large volumes of water that could have recharged groundwater and surface water bodies are diverted into the municipal drainage system and lost from the freshwater storage. Moreover, extreme rain events impose high peak flows and large runoff volumes, which increase the risk of urban floods. Recent studies have suggested the use of rainwater harvesting for groundwater recharge, as a plausible solution for these challenges in dense urban environments. While the benefits of this approach are well understood, research on its practical, engineering, and hydrological aspects is relatively limited. The objective of the present study was to examine the use of infiltration wells for groundwater recharge with harvested rainwater collected from building rooftops under Mediterranean climate conditions. Two types of wells with similar hydraulic and technical properties were examined: a well that reaches the groundwater (wet well); and a well that discharges the harvested water into the unsaturated zone (dry well). Infiltration capacities of the wells were compared in controlled experiments conducted during summer months, and in operational recharge of harvested rainwater, during winter. Both dry and wet wells were found to be suitable for purposes of groundwater recharge with rooftop-harvested rainwater. Infiltration capacity of the wet well was about seven times greater than the infiltration capacity of the dry well. While the infiltration capacity of the wet well was constant throughout the entire length of the study (∼10 m3/h/m), the dry well infiltration capacity improved during winter (from 0.5 m3/h/m to 1.5 m3/h/m), a result of development of the dry well with time. Considering Tel-Aviv, Israel, as a case study for a dense modern city in a Mediterranean climate, it is demonstrated herein that the use of infiltration wells may reduce urban drainage by ∼40 %.

Ni / GDC Fuel Electrode for Low Temperature SOFC and its Aging Behavior under Accelerated Stress

For the increase of the number of the potential applications of SOCs as well as a lower system cost, realization of operating at lower temperatures (< 650 °C) is a key point. However, the overall cell performance would decrease dramatically with reduction in temperature because of reducing ionic conductivity in electrolyte and increased polarization resistance from both electrodes. In case of realizing high performance yet also good mechanical stability, wet infiltration is shown to be one effective method [1].In this contribution, the concept of infiltration is presented with a GDC infiltrated Ni-Skeleton fuel electrode. With this approach, a polarization resistance of below 0.2 Ω cm² at 600 °C is realized. To study the durability of such electrode, the concept of accelerated testing is applied. Symmetrical cells are tested to avoid an additional impact of the air electrode [2]. The cells are operated at temperatures up to 900 °C and a high steam content of 50 % for up to 1000 h. Electrochemical impedance spectroscopy (EIS) is employed to record the temporal development of the electrode performance. By means of the distribution of relaxation times (DRT), the temporal evolution of the loss processes is identified. As an example, impedance and DRT at 600 °C before and after aging at 900 °C for 650 h is presented in Figure 1(c). Microstructural analysis of electrode in different aging status is carried out with optical- and electron microscopy. The initially nanoscaled microstructure of the infiltrated GDC, as presented in Figure 1(a), is agglomerated (Figure 1(b)) during aging at elevated temperatures, which is in agreement with the observed increase in polarization resistance.KeywordsSolid Oxide Fuel Cell; low temperature; porous electrodes; accelerated life time test; aging phenomenon; GDC; SEM[1] Z. Liu.et al., J. Power Sources, 237, p. 243 (2013)[2] C. Endler-Schuck.et al., J. Power Sources, 196 (17), p. 7257 (2011).[3] S. Dierickx.et al., Electrochim ica Acta, 355, p. 136764 (2020).[4] A. Weber, tm - Technisches Messen, 88 (1), p. 1 (2021).[5] C. Grosselindemann.et al., ECS Trans., 103 (1), p. 1375 (2021). Figure 1

Metal-oxide nanocomposite catalyst simultaneously boosts the oxygen reduction reactivity and chemical stability of solid oxide fuel cell cathode

Conductive perovskite oxides have received much attention as promising candidates for solid oxide fuel cell (SOFC) cathodes. However, they show chemical instability due to the segregation of A-site cations on the surface at high temperatures, which causes their performance to degrade. Moreover, the high activation barrier to oxygen reduction reactions makes these materials more difficult to use as electrodes at lower temperatures (less than 700 °C). Herein, by combining two general techniques: nanoparticle infiltration and atomic layer deposition (ALD), we significantly improve both the durability and reactivity of a state-of-the-art perovskite oxide, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF). Ag nanocatalysts are dispersed onto an LSCF cathode via wet infiltration, after which they are covered with a thin ZrO2 layer via ALD to prevent the agglomeration of nanocatalysts and the segregation of Sr ions. Accordingly, the Ag/ZrO2 nanocomposite-deposited LSCF cathode shows the electrode resistance of 0.085 Ωcm2 at 650 °C over 200 h, which is, to the best of our knowledge, the near-record level among all nanocatalyst-infiltrated LSCF cathode to date. Our result suggests a new research direction to fully utilize nanocatalysts and perovskite oxides in SOFCs, which can be a shortcut to their commercialization.

A critical review of the nano-structured electrodes of solid oxide cells.

Renewable energies from solar and wind power are playing an ever increasing role in meeting the tremendous global energy demand with substantially reduced carbon emissions; however, their intermittent nature poses a critical challenge for sustainability and practical applications. The capability of solid oxide cells (SOCs) to operate in both fuel cell and electrolysis modes makes them one of the most important candidates for efficient storage and regeneration of renewable energies. Here we present a critical review and prospects on the development of key fabrication techniques, e.g. wet infiltration, exsolution and direct assembly, for nanostructured electrodes, one of the most critical issues affecting the performance and stability of SOC technologies. The traits and challenges of these techniques are thoroughly discussed, with an aim to provide a critical guide for future design and development of more refined, high-performing nanostructured electrodes for SOCs.

Selection of Highlights of the European Project Next Generation Solid Oxide Fuel Cell and Electrolysis Technology – NewSOC

Solid oxide technologies (SOC: Solid oxide fuel cells SOFC & Solid oxide electrolysis SOE) are key enabling technologies for energy systems based on renewable sources and allow for a strong interlinking of sectors electricity, heat, and gas/fuels. SOC can emerge as key players in many concepts, such as fuel/gas to power and heat at small to large scale,energy storage through power to hydrogen/fuel,utilization and upgrading of biogas,balancing of intermittent electricity from renewable sources through load following and reversible operation, andcentral and decentral solutions for electricity and heat production. In a time, where first SOC systems enter demonstration and commercial markets, the NewSOC project focusses on next generations. It aims at significantly improving performance, durability, and cost competitiveness of solid oxide cells & stacks compared to state-of-the-art (SoA). In order to achieve these goals, NewSOC investigates twelve innovative concepts in the following areas: (i) structural optimization and innovative architectures based on SoA materials, (ii) alternative materials, which allow for overcoming inherent challenges of SoA, (iii) innovative manufacturing to reduce critical raw materials and reduction of environmental footprint at improved performance & lifetime. The NewSOC unifies competences of 16 strong research and industry players. First scientific highlights were achieved despite the challenging working conditions under the European wide covid-19 restrictions in the first year of the project. The presentation will provide a selection of these highlights.One focus area is the development of novel electrode materials, where high performance, impurity tolerance and stability are the primary targets. Nanostructured fuel electrodes based on doped SrTiO3 perovskites such as LaSrFeNiTiO3 are being developed as backbones. Subsequent, wet infiltration of Ni:GDC ensures high electro catalytic activity and ionic conductivity, while retaining the advantages of Ni-metal free fuel electrodes outlined above. Furthermore, a class of doped lanthanum chromites (La0.75Sr0.25CrxM1-xO3-δ, M=Fe, Mn, Ni) is developed as Ni-metal free fuel electrodes, to overcome the challenges faced by the SoA Ni-cermets. The perovskite structured electrodes, combined with highly conductive electrolytes have high performance, low ASR and flexibility in various operating modes (SOEC, rSOC). The most attractive feature of this class of electro catalysts is that they retain their properties (oxidative state, conductivity) in reducing and oxidizing environments at SOC operating temperatures, even in absence of a reducing agent, i.e. H2.Another approach is to modify SoA electrodes. Commercial (SoA) Ni/GDC was modified with iron by deposition – precipitation (D.P.), leading to enhanced performance as functional SOE fuel electrode. The promoting effect depends on the wt.% Fe content, where D.P. of quite a small amount of iron, through the formation of a Ni-Fe alloy, caused a 3-fold enhancement compared to Ni/GDC. Interestingly, the 0.5-Fe-Ni/GDC electrode performed similarly well like the noble-metal modified 3Au-0.3Mo-Ni/GDC.Materials compositions and structuring go hand in hand for tailoring cell properties. Under this focus, novel air electrode architectures for SOFC & SOE applications based on Co- and Ni-free materials with the (La, Ca, Sr)FeO3 perovskite class of materials are developed. The typically increased overpotential of Co- and Ni-free air electrodes is a challenge, which is tackled by introduction of a patterned porous barrier layer and addition of a composite layer at the electrode/electrolyte interface to enhance the triple phase boundary density between electrolyte and the Co-free air electrode. In another approach, the microstructure of SoA Ni/YSZ and LSCF/GDC electrodes was assessed to identify the best tradeoff between the cell performances, the durability and the robustness by a methodology coupling of manufacturing, characterization, and modeling. As a result, the performance of the LSCF/GDC composite electrode was improved, with different porosities, graded electrodes and composites. The role of the Ni/YSZ microstructure on the Ni migration during operation was investigated, with focus on finer and more homogeneous electrodes.Manufacturing and deposition methods contribute significantly to performance & lifetime, but also costs and environmental impact of SOC production. Thus, alternative approaches providing cells & stacks with required specifications are part of the NewSOC project. Progress on sputter deposited GDC buffer layers has been obtained in view of their implementation in the fabrication process of commercial Solid Oxide Fuel Cells.

Improvement in the Electrochemical Performance of Anode‐supported Solid Oxide Fuel Cells by Meso‐ and Nanoscale Structural Modifications

AbstractTo improve the electrochemical performance of anode‐supported solid oxide fuel cells (SOFCs), microextrusion printing and wet infiltration techniques are employed for structural modification on the meso‐ (10–100 µm) and nanoscale order, respectively. In the mesoscale structural modification, anode ridge structures are fabricated by extruding an anode slurry on the surface of a flat anode disk to extend the electrode–electrolyte interfacial area. In the nanoscale structural modification, gadolinium‐doped ceria (GDC) nanoparticles are introduced into a porous lanthanum strontium cobalt ferrite (LSCF) cathode. To investigate the effects of mesoscale and nanoscale structural modifications, four different types of anode‐supported SOFC including a conventional cell are prepared, and their performance is evaluated at several operating temperatures. It is found that both the mesoscale and nanoscale structural modifications reduce not only the polarization resistance but also the ohmic resistance in the cells, resulting in the improvement in cell performance. Moreover, it is clarified that the improvement in cell performance becomes greater with decreasing operating temperature. Specifically, the maximum power density in the cell where both mesoscale and nanoscale structural modifications are applied is increased by 66% at 600 °C and 34% at 700 °C, compared with that in the conventional cell.

Polyimide fabric-reinforced polyimide matrix composites with excellent thermal, mechanical, and dielectric properties

Two types of thermosetting polyimide (PI) resin were prepared using a polymerization monomeric reactant method, and high performance PI fabric/PI resin composites were fabricated through a wet infiltration and thermoforming process. The properties of a PI fabric, PI resin, and PI/PI composites were comprehensively analyzed. The experimental results indicate that a resin end-capped with phenylacetylene achieves a better processability and heat resistance. The two composites exhibit excellent thermal, mechanical, and dielectric properties. They achieve a glass transition temperature of higher than 320°C and a 5% weight loss temperature of over 600°C under an air atmosphere. During mechanical testing, an interlaminar shear strength exceeding 35 MPa was achieved, whereas the maximum flexural strength was found to be greater than 400 MPa. Moreover, their dielectric constant at 1 MHz was below 3.4, with a dielectric loss of no more than 0.01.

Gas-Permeable Inorganic Shell Improves the Coking Stability and Electrochemical Reactivity of Pt toward Methane Oxidation

Solid oxide fuel cells produce electricity directly by oxidizing methane, which is the most attractive natural gas fuel, and metal nanocatalysts are a promising means of overcoming the poor catalytic activity of conventional ceramic electrodes. However, the lack of thermal and chemical stability of nanocatalysts is a major bottleneck in the effort to ensure the lifetime of metal-decorated electrodes for methane oxidation. Here, for the first time, this issue is addressed by encapsulating metal nanoparticles with gas-permeable inorganic shells. Pt particles approximately 10 nm in size are dispersed on the surface of a porous La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) electrode via wet infiltration and are then coated with an ultrathin Al2O3 layer via atomic layer deposition. The Al2O3 overcoat, despite being an insulator, significantly enhances the immunity to carbon coking and provides high activity for the electrochemical oxidation of methane, thereby reducing the reaction impedance of the Pt-decorated electrode by more than 2 orders of magnitude and making the electrode activity of the Pt-decorated sample at 650 °C comparable with those reported at 800 °C for pristine LSCM electrodes. These observations provide a new perspective on strategies to lower the operation temperature, which has long been a challenge related to hydrocarbon-fueled solid oxide fuel cells.

Improved controllability of wet infiltration technique for fabrication of solid oxide fuel cell anodes

Ni/yttria-stabilized zirconia anodes of solid oxide fuel cells are fabricated by a wet infiltration technique and the ability of the infiltration technique to control the anode microstructure is quantitatively demonstrated by a detailed three-dimensional microstructural analysis. The microstructural analysis reveals favorable aspects of the infiltrated anodes, such as larger triple-phase boundary density and sufficiently large pore size, and they are mostly unachievable by the conventional powder-mixing and sintering approaches. The improved controllability of the infiltration technique is expected to be useful to tailor porous microstructures to meet the multiple requirements for transport and electrochemical reactions within the anodes.

Shaped Silica-polyethyleneimine Composite Sorbents for CO2 Capture via Adsorption

Mesocellular siliceous foam (MCF) - branched polyethyleneimine (BPEI) composite powders were prepared via wet infiltration, then processed in accord with patented shaping technology, to produce robust MCF-BPEI composite pellets. Thermogravimetric analysis of CO2 partial pressure swing adsorption (PPSA) processing of these sorbents was conducted to assess their potential for application to CO2 post combustion capture (PCC) via adsorption processes, under anhydrous and highly humidified (15% H2O) conditions. The pellet products were found to provide large CO2 working capacities and high water tolerance under key process conditions, and, so, are considered highly prospective for CO2 PCC.

Electrochemical Analysis of Ni Infiltrated Nanoporous GDC Scaffold for Metal Supported SOFCs Anode

Metal-supported SOFCs have been investigated to overcome the disadvantages of ceramic-supported SOFCs, such as mechanical strength and sealing. In the case of ceramic-supported cells, the mechanical support is a brittle ceramic or cermet, and it contains expensive materials. However, metal-supported cells utilize ceramic layers that are only as thick as necessary for electrochemical functioning, thereby compensating for the disadvantages of ceramic-supported cells. The mechanical support is fabricated from inexpensive and robust metals, and the electrochemically active layers are applied directly to the metal support. In other words, metal-supported SOFCs can provide a reduced system cost, easy manufacturing, and operational advantages. These features make metal-supported SOFCs a very promising candidate for commercialization. To improve productivity and accelerate the commercialization, the metal supported SOFCs have to be fabricated at low temperature under oxidized environment. In these days, some metal substrates which can withstand corrosion from ≤1000 °C already have been developed. However, the low fabrication temperature is insufficient for conventional sub-micron scaled NiO/YSZ or GDC to generate smooth electrical and ionic paths. Furthermore, the unsuitable anode can affect to interfaces; and as a result, it can cause decrease of electrical conduction. Therefore, we have tried to apply a wet infiltration technique for anode fabrication. It can fabricate nanosize particles into a porous scaffold at relatively low temperatures and achieve higher performance electrode structures. Then, to substitute the conventional anode, a nanoporous GDC scaffold layer, and the Ni solution were selected as a scaffold and catalyst material, respectively. It is known that the GDC has high ionic conductivity and can be sintered at relatively low temperature. Therefore, it was considered that the GDC could be well matched with the requirements for anode of metal supported SOFC. For investigating the electrochemical performance according to Ni amounts, the half-cell tests were carried out via solatron 1287/1260 device under 97%H2+3%H2O condition. Then, the appropriate Ni infiltrated GDC was applied to the metal-supported SOFC, and the electrochemical performance of infiltrated metal-supported SOFC single cell was measured via the solatron 1287/1260 device.

Synthesis of ordered mesoporous carbon using m-Diethynylbenzene as a new precursor

m-Diethynylbenzene (m-DEB) was used for the first time as a precursor in the synthesis of mesoporous carbons(OMCs) via the wet infiltration method. The results from X-Ray powder diffraction, Transmission electron microscopy, N2 adsorption-desorption isotherms and TGA curves confirmed that after carbonization at 800°C, 1000°C, 1200°C and removal of the template, OMCs with very narrow pore size distributions (centered at about 4nm), high order and relative high thermal stability(as high as 600°C for OMC-800) were obtained. This work provided a facile way to prepare ordered mesoporous carbon materials with relative high thermal stability.

A La0.8Sr0.2MnO3/La0.6Sr0.4Co0.2Fe0.8O3−δ core–shell structured cathode by a rapid sintering process for solid oxide fuel cells

A La0.8Sr0.2MnO3 (LSM)/La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) core–shell structured composite cathode of solid oxide fuel cells (SOFCs) has been fabricated by wet infiltration followed by a rapid sintering (RS) process. The RS is carried out by placing LSCF infiltrated LSM electrodes directly into a preheated furnace at 800 °C for 10 min and cooling down very quickly. The heating and cooling step takes about 20 s, substantially shorter than 10 h in the case of conventional sintering (CS) process. The results indicate the formation of a continuous and almost non-porous LSCF thin film on the LSM scaffold, forming a LSCF/LSM core–shell structure. Such RS-formed infiltrated LSCF–LSM cathodes show an electrode polarization resistance of 2.1 Ω cm2 at 700 °C, substantially smaller than 88.2 Ω cm2 of pristine LSM electrode. The core–shell structured LSCF–LSM electrodes also show good operating stability at 700 °C and 600 °C over 24–40 h.

An easy and innovative method based on spray-pyrolysis deposition to obtain high efficiency cathodes for Solid Oxide Fuel Cells

A novel electrode preparation method based on the spray-pyrolysis deposition of metal nitrate solutions onto a porous electrolyte scaffold is proposed. This method has been proved with different cathode materials, usually used in Solid Oxide Fuel Cells, such as La0.8Sr0.2MnO3−δ and La0.6Sr0.4Co1−xFexO3−δ (x = 0, 0.2, 0.8 and 1). The electrode microstructure is composed by two layers; the inner layer is a porous electrolyte scaffold homogeneously coated by cathode nanoparticles, providing an increased number of triple phase boundary sites for oxygen reduction, whereas, the top layer is formed by only cathode nanoparticles and acts mainly as a current collector. Polarization resistance values as low as 0.07 and 1.0 Ω cm2 at 600 and 450 °C, respectively, are obtained at open circuit voltage. This alternative approach has several advantages with respect to the traditional wet infiltration method for large area electrode fabrication, such as higher reproducibility, shorter preparation time in a single thermal deposition step, and easy implementation at industrial scale as a continuous process.

Detailed Study of the Nanocasting Process by in Situ X-ray Scattering and Diffraction

The nanocasting method is a valuable tool for producing metal oxides with a well-defined nanostructure. However, the precise details on how the metal oxide is developed inside the mesoporous silica template remain unclear. In this study, we clarify how nickel nitrate species are evolving to nickel oxide and how they are redistributed inside mesoporous SBA-15 particles as a function of heating temperature and surrounding gas atmosphere by a combination of in situ small-angle X-ray scattering, X-ray diffraction and thermogravimetric techniques as well as ex situ transmission electron microscopy and nitrogen physisorption measurements. The SBA-15 template was initially impregnated with Ni(NO3)2·6H2O using the wet infiltration method. The results indicate an initial redistribution of the nickel nitrate salt located outside the pore system into the mesopores due to dissolution, while at temperatures of 110–150 °C (depending on which type of gas flow is used) the mobility of the salt is lost due to drying of th...

Electrochemical Analysis of Nano-Infiltrated Solid Oxide Fuel Cell Cathodes

Composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds infiltrated with mixed ionic and electronic conducting (MIEC) nano-particles have exhibited some of the lowest reported polarization resistances in the literature. In this study, symmetric cell cathodes were prepared via wet infiltration of Sr0.5Sm0.5CoO3 (SSC) nano-particles via a nitrate process into porous Ce0.9Gd0.1O1.95 (GDC) scaffolds to be used as a model system to investigate performance under varying infiltration loadings. Detailed analysis of the infiltrated cathodes was carried out using electrochemical impedance spectroscopy (EIS). The results presented show that the infiltrated cathode microstructure has a direct impact on the initial performance of the cell. Small initial particle sizes and high infiltration loadings (up to 30 vol% SSC) improved initial polarization resistance (RP). A simple microstructure-based electrochemical model successfully explained these trends in RP. Further understanding of electrode performance was gleaned from fitting EIS data gathered under varying temperatures and oxygen partial pressures to equivalent circuit models. Both RQ and Gerischer impedance elements provided good fits to the main response in the EIS data, which was associated with a combination of oxygen surface exchange and oxygen diffusion in the electrode. A gas diffusion response was also observed at relatively low pO2.

Performance and durability of anode-supported flat-tubular solid oxide fuel cells with Ag-infiltrated cathodes.

An anode-supported flat-tubular solid oxide fuel cell is an advanced cell design, which offers many advantages including a high volumetric power density, a minimized sealing area and a high resistance to thermal cycling. Infiltration of nano-sized noble metal catalysts into a porous cathode is known to be an effective method to improve cathode performances at reduced temperatures, but the cathode stability is of potential concern. This study addresses the performance and durability of anode-supported flat-tubular solid oxide fuel cells with Ag-infiltrated cathodes. Uniformly dispersed Ag nanoparticles on the cathode are formed via a wet infiltration technique combined with subsequent heat-treatment. Although the Ag infiltration results in improved cell performance, the durability tests indicate that the cell performance degrades over time and that the degradation rate increases with increasing Ag loading in the cathode. The observed performance degradation is mainly attributed to formation of large-scale Ag agglomerates. A strategy based on an inter-dispersed composite of Ag and CeO2 nanoparticles is proposed to mitigate the performance degradation.

Microstructural refinement of Ni/Ce0.8Gd0.2O2−δ anodes for low-temperature solid oxide fuel cell by wet infiltration loading of PdCl2

Microstructural refinement of Ni/Gd0.2Ce0.8O2−δ (Ni/GDC20) anode by wet-infiltration of PdCl2 precursor was studied to further improve the anodic performance of low temperature solid oxide fuel cell (LT-SOFC). The effect of <1wt% of Pd loadings on polarization resistance of Ni/GDC cermet anodes for H2 oxidation reaction was examined using symmetric Ni–GDC20|GDC20|Pt electrolyte-supported cells at 400–600°C. Nanostructure evolution before and after H2 reduction at 600°C and also after anodic performance test revealed effectiveness of PdO loading content on the nanoparticles architecture, with PdO as the sole Pd-phase after calcination at 600°C with no residual chloride. In the process of H2 reduction in high loading of PdO (0.26mg/cm2), a nano-grained network of metallic palladium (Pd0) containing nanopores structure, which resulted from 40% volume deoxidizing shrinkage of PdO, was developed on the anode surface. But, in the case of small loading, PdHx phase indicating of H affinity of palladium and minute amounts of PdO on NiO were detected. The significant decrease of anodic polarization resistance, e.g. ~100 times at 500°C, on highly Pd-infiltrated anode was accompanied with≤40nm agglomerates in Pd-nanonetwork and 45% oxidizing of Pd0 to PdO in H2 environment. Detailed anodic impedance analysis and activation energy (Ea) evaluation can be denoted to a balance between the Ea of reaction-limiting step of charge transfer and the Ea of the facilitating step of diffusion/adsorption/dissociation of the arrived O2− species to triple phase boundaries (TPBs). Our findings verified that oxygen spillovering on the Pd0/PdO-pair nanocoating caused by the shift of the TPBs to the nanocoating-pair for H2 oxidation reaction in LT-SOFC.

Thermal stability of silver-MOx (M = Mn, Fe, Co, Ni) Composite Cathode for IT-SOFCs

Silver nano composite cathode is expected as one of the new materials for intermediate temperature SOFCs cathode. Characteristics of silver are high conductivity and oxygen ion conductivity so it is a suitable material. Generally the silver were introduced by wet infiltration method. Infiltrating Ag powder into LSCF, the maximum output power was improved. However, the power density decreased with time above 700 ºC, because of the growth of Ag particle. In this study, we have synthesized Ag and transition metal oxides (MOx, M = Mn, Fe, Co, Ni) composite cathode with various mixing ratio using AgNO3 and MNO3 solutions in citric acid. The material of electrode is able to make in a nano composite electrodes by oxide into Ag at intermediate temperature. In the characteristic of electrochemical, power density of Ag-NiO electrode on anode supported cell was increased from 0.098 W/cm2 to 0.612W/cm2 at 700 ºC.