Analysis of the electronic and ionic conductivity of. Preparation of nanocomposite gdclscf cathode material for. Pdf electrical conductivity of lscf thin films for sofc. Electrical conductivity is the movement of charge in response to an electric field. Lscf undergoes phase transformations at various temperatures depending on the composition. Effects of ceria conductivity on the oxygen incorporation at the lscfsdcgas threephase boundary. Experimental investigations of the microscopic features. Conductivity measurement is an extremely widespread and useful method, especially for quality control purposes. The conductivity of thin films deposited onto micro hotplates was in the same order. It is because ysz has lower ionic conductivity than sdc at 673 k. Effect of the ionic conductivity of the electrolyte in. The ionic conductivity of cgo is higher than the ionic conductivity of lscf at intermediate sofc temperatures 14. The process is thermally activated conductivity increase with temperature.
Predicting ionic conductivity of solid oxide fuel cell. The calculation of the conductivity of a twophase mixture, for example an. May 14, 2019 by this way, the ionic conductivity of 600 c and c pellet are 0. It is reported that after infiltration with ionic conductive gdc, the microstructure stability, the ionic conductivity,the oxygen reduction activity as well as the adhesion to electrolyte of lscf cathode could be improved2531. Enhanced performance of lscf cathode through surface. Moreover, the ionic composition of the water can be critical.
Due to the inherent high ionic conductivity, many sims have been. Lscf with very high electronic conductivity 320 scm at 700 oc,6 directly mixed with lst to make a composite. Effect of asite nonstoichiometry on lscf cathodes jw templeton jw stevenson z lu js hardy september 2011 prepared for the u. Threedimensional chemical potential and current vector distributions inside lscf microstructure are presented. Lscf cathodes have been commonly used at intermediate sofc operational temperatures due to a number of physicochemical. Obviously, the lscfscdc pellet sintered at 600 c possessed higher ionic conductivity than that of c pellet, which resulted in the better electrochemical performance of the assembled fuel cell. These properties are discussed in combination with oxygen nonstoichiometry and the diffusion constant of oxide ions. Itsofcs due to mixed ionicelectronic conductivity and high. Enhancing grain boundary ionic conductivity in mixed ionic. It is reported that after infiltration with ionic conductive gdc, the microstructure stability, the ionic conductivity,the. Preparation of nanocomposite gdclscf cathode material for it. So adding to this material another miec material, such as cgo, which has a high ionic conductivity, is effective in. Predicting ionic conductivity of solid oxide fuel cell electrolyte from.
Lscf with very high electronic conductivity 320 scm at 700 oc,6 directly mixed with lst to. Nano express open access the sintering temperature. Parallel infiltration procedures were studied in a comparative study. Lanthanum strontium cobalt ferrite lscf, also called lanthanum strontium cobaltite ferrite is a specific ceramic oxide derived from lanthanum cobaltite of the ferrite group. Lscf and ionic conductor sm and ca codoped ceria ce 0.
Ionic conductivity and its role in oxidation reactions. The ionic conductivity is very small in comparison with the total conductivity in fig. Experimental investigations of the microscopic features and. The ionic conductivity of lscf and bscf are enough high in comparison to doped cerias typical electrolytes. Determination of surface exchange coefficients of lsm, lscf. Percolation theory in solid oxide fuel cell composite.
The magnitude of the conductivity value is directly related to electrolytic. Lscf is often used as sofc cathode material, especially for operation of sofc at temperatures between 500 700c 10. P0603beckel electrical conductivity of lscf thin films for. And sdc is just the opposite since it s a complete ionic conductor. The sintering temperature effect on electrochemical properties of ce0. The electrical conductivity of several ionic salts, both in the solid and liquid state, have been investigated as a function of temperature refs. The conductivity of ionic salt mixtures, however, has not been reported, except for a few cases ref. Infiltration strategies the commonly used infiltration strategies could be classified by the type of. Free fulltext pdf articles from hundreds of disciplines, all in one place the sintering temperature effect on electrochemical properties of ce0. For example, cladocerans water fleas are far more sensitive to potassium chloride than sodium chloride at the same concentration. Pdf electrical conductivity of lscf thin films for sofc on.
Reports enhanced sulfur and coking tolerance of a mixed ion. Surveillance of feedwater purity, control of drinking water and process water quality, estimation of the total number of ions in a solution or direct. For the lscf membranes studied in this work, electronichole trans port dominates the electric conduction. The conductance g of a solution is defined as the inverse of the resistance. Mixed ionicelectronic conductors in the family of laxsr1xcoyfe1yo3d lscf have been widely studied as cathode materials for solid. The ionic conduction process should be located at the lowfrequency arc. A multiscale model for electrochemical reactions in lscf. The high molecular weight of hydrocarbon consisted in the polypropylene oil i. A novel integrated design for the mixed ionicelectronic.
At 1073 k, the ionic conductivity has a maximum value of 0. This material could potentially reduce the polarization. The resulting nanocomposite powders consisted of two kinds of nanopowders with different mass ratio of gdc lscf, such as 37 and 64. Ionic conductivity in crystalline polymer electrolytes nature. Yu zhong mechanical engineering, worcester polytechnic institute, worcester, ma 01609 perovskites with excellent mixed ionic electronic conductivity miec are the most promising. Previous research also shows that electrolyte materials such as samariumdoped ceria sdc and gadoliniumdoped ceria gdc are mixed with lscf to enhance the ionic conductivity of the cathode 5,6,11,12,15,16. It exhibits high ionic conductivity at relatively low temperatures 500 to 700c. Its ability to resist deactivation by sulfur and coking appears linked to the mixed conductors enhanced catalytic activity for sulfur oxidation and hydrocarbon. The electronic and ionic conductivity, the tec, and the expansion on reduction of a. This is explained in terms of reduced mobility of the oxygen vacancies in the a highly reduced ceria. When we compared the conductivities of bzcyyb with those of several. The sintering temperature effect on electrochemical. Pdf technologies established for microsystems combined with electronic and ionic conducting oxides made by thin film deposition.
Conductivity equations the conductivity contribution of a single interface bicrystal experiment can be calculated analytically by integration of the conductivity pro. Electrical conductivity of lscf thin films for sofc on micro hotplates. Department of energy under contract deac0576rl01830 pacific northwest national laboratory richland, washington 99352. Thus forming a percolative cgo nanoparticle pattern on the surface of the lscf. Through the doping energy levels within band gap will be created.
Enhanced performance of lscf cathode through surface modification. Ionic conductivity in crystalline polymer electrolytes. However, lscf reacts with ysz to form resistive zirconate phases at temperatures as low as 800. This has reduced the sofc operating temperature to below 800 c. Lanthanum strontium cobalt iron oxide lscf is a state of the art mixedionicelectronicconducting miecsolid oxide fuelcell sofc cathode material with high ionic and electronic conductivity. Lscf heterostructure pellet nanoscale research letters, may 2019. Lscf has high ionic conductivity at intermediatetemperature operations 4, 5. P0603beckel electrical conductivity of lscf thin films. Miec material, is a ptype semiconductor with electronic and ionic conductivity.
Further dope or replacement of manganese with other elements such as cobalt and iron lscf increased the electrical and mechanical. Electrical conductivity and dimensional stability of codoped. Conductivity is the ability of water to conduct an electrical current, and the dissolved ions are the conductors. In order to reveal the ionconducting mechanism in sim, a typical sim pellet. The electrical conductivity was measured by the fourprobe dc method, at. Pdf electrical conductivity of lscf thin films for sofc on micro. John owen, in comprehensive polymer science and supplements, 1989. Determination of surface exchange coefficients of lsm.
Porous lscf dense 3ysz interface fracture toughness measured by single cantilever beam wedge test xin wanga, fei heb, zhangwei chena and alan atkinsona a department of materials, imperial college london sw7 2bp, uk b key laboratory of science and technology on advanced composites in special environments, harbin institute of technology, p. Lscf was studied with xrd in controlled atmospheres. On the contrary, the ysz conductivity remains unperturbed and shows the same values of about 0. Lscf has higher ionic conductivity than lsm, which is why d is much higher as well. Reports enhanced sulfur and coking tolerance of a mixed. It was found that lscf has a phase transition from rhombohedral to cubic, occurring at about 773 k. A study on ionic conductivity and sofc performance of doped ceo. This involves the movement of an ion from one site to another through defects in the crystal lattice of a. Conductivity in solutions revised 42815 2 the solution conductance has the units of inverse ohms. First principles, electronic structure simulations. Conductivity in solutions revised 42815 4 h 2so 4 is a strong acid, and should be handled with care.
Thus forming a percolative cgo nanoparticle pattern on the surface of the lscf grains can enhance tpb length creating additional oxygen ionconducting paths and improving the electrochemical performance of the cathode. Mixed ionicelectronic conductive miec perovskite material. For the smallest layer thickness of 2 nm the doped ceria layers are electrically insulating and the ionic transport only occurs through the zirconia layers. Conductivity of electrolyte solution ions in solution can be set in motion by applying a potential difference between two electrodes. Fast ionic conductivity of solid electrolytes is a must in the development of nextgeneration solidelectrolytebased lithiumion batteries. The electrolyte materials have high ionic conductivities and rapidly exchange as seen in fig. Remarkable ionic conductivity and catalytic activity. Preparation and characterization of sm and ca codoped. The effects of the microstructure parameters, such as the volume fraction of the lscf material, the particle size distributions of both the lscf and ysz. Ionic conductivity, like electronic conductivity, can be broken down into a product of three terms.
In the conventional view of ionic conductivity in polymer electrolytes, ions move in a dynamic environment created by the polymer chain motion in the amorphous phase above t g. Enhancing grain boundary ionic conductivity in mixed ionicelectronic conductors article in nature communications 6. The sintering temperature effect on electrochemical properties of ce. Conductivity measurements cover a wide range of solution conductivity from pure water at less than 1x107 scm to values of greater than 1 scm for concentrated solutions.
Ionic conductivity an overview sciencedirect topics. Porous lscfdense 3ysz interface fracture toughness. Paper open access polypropylene oil as a fuel for niysz. Electric transport and oxygen permeation properties of lanthanum. Porous lscfdense 3ysz interface fracture toughness measured. Solid state ionics georgia institute of technology. Lscf has good ionic conductivity, its electronic conductivity is much more relevant. One possible strategy is to mix lscf with the electrolyte gadoliniadoped ceria gdc. This involves the movement of an ion from one site to another through defects in the crystal lattice of a solid or aqueous solution. Threedimensional numerical analysis of mixed ionic and. Obtain a 50 ml buret and prerinse the buret with a few ml of the h2so4 solution. The electrical conductivity was measured by the fourprobe dc method, at temperatures 9731173 k, in the p o 2 range of 110. The miec perovskites can be predicted by considering these two conductivities at the same time. Ionic conduction ionic conduction is caused by the movement of some negatively or positively charged ions which hop from lattice site to lattice site under the influence of an electric field.
Inkjet printing functionalization of sofc lscf cathodes. Previous research also shows that electrolyte materials such as samariumdoped ceria sdc and gadolinium. Due to its high ionic conductivity and compatibility with cobaltitebased cathode compounds, doped ceria is commonly used as in. The electrical conductivity of the thin film nanograined lscf was measured on the micro hotplate as a function of temperature and compared to reference samples deposited onto bulk substrates. The crystal structures of scdc, lscf, and their corresponding pdf card. It is reported in literature that the oxygen reduction reaction at lscf. Enhanced performance of lscf cathode through surface modi. Because the literature values were used as initial guesses in the model, it is no surprise that they agree, having similar activation energies. Interface effects on the ionic conductivity of dopedceria. Although numerous studies, both experimental and theoretical, suggest that the ionic conductivity of the electrolyte within compos. The importance of conductivity conductivity measurement is an extremely widespread and useful method, especially for quality control purposes.
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