CN115241477A - Easily-dispersible SOFC cathode powder and preparation method and application thereof - Google Patents

Easily-dispersible SOFC cathode powder and preparation method and application thereof Download PDF

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Publication number
CN115241477A
CN115241477A CN202210926585.4A CN202210926585A CN115241477A CN 115241477 A CN115241477 A CN 115241477A CN 202210926585 A CN202210926585 A CN 202210926585A CN 115241477 A CN115241477 A CN 115241477A
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nitrate
wood fiber
water
sofc cathode
mixed solution
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Inventor
唐钰栋
张晓娇
马腾飞
赵世凯
张久美
冯雪莲
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Shandong Industrial Ceramics Research and Design Institute Co Ltd
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Shandong Industrial Ceramics Research and Design Institute Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
    • H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
    • H01M4/9033—Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8803—Supports for the deposition of the catalytic active composition
    • H01M4/881—Electrolytic membranes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Abstract

The invention provides easily-dispersible SOFC cathode powder and a preparation method and application thereof, and the easily-dispersible SOFC cathode powder comprises the following steps: mixing nitrate, urea, water-soluble starch and water, and stirring until the nitrate, the urea, the water-soluble starch and the water are completely dissolved to obtain a mixed solution; soaking the wood fiber into the mixed solution until the wood fiber is saturated in absorption, so as to obtain saturated wood fiber; and drying the saturated wood fiber, calcining and ball-milling to obtain the easily-dispersed SOFC cathode powder. The wood fiber is immersed in the mixed solution until the mixed solution is saturated, the mixed solution is uniformly immersed in the wood fiber, the wood fiber is loose and porous, the heat generated in the combustion reaction can be effectively dissipated during calcination, the growth of crystal grains is avoided, and the synthesis of nano powder is facilitated; in addition, wood fibers are combusted during calcination, and after calcination, the wood fibers are uniformly distributed around the powder particles in the form of residual carbon powder, so that the powder particles are effectively isolated, the powder particles are easy to disperse during preparation of the cathode, and large aggregates cannot be generated.

Description

Easily-dispersible SOFC cathode powder and preparation method and application thereof
Technical Field
The invention relates to the technical field of solid oxide fuel cells, in particular to easily-dispersed SOFC cathode powder and a preparation method and application thereof.
Background
A Solid Oxide Fuel Cell (SOFC) is a power generation device that directly converts chemical energy of fuel into electric energy, has the advantages of high energy conversion efficiency, wide fuel application range, low pollutant discharge amount and the like, can be used in the fields of power generation, thermoelectric recycling, traffic, space aerospace and the like, and is called green energy of the 21 st century.
The cathode is one of the important components of the solid oxide fuel cell, provides an electrochemical reaction site for the reduction of oxygen, and the performance of the cathode directly influences the performance of the whole cell. The cathode of the solid oxide fuel cell has strict requirements on the particle size, crystal structure, micro morphology and electrochemical performance of the cathode powder as a raw material, and the most ideal cathode powder has the characteristics of small and uniform particles, no impurity phase in phase composition, complete and clear lattice boundary, uniform and regular arrangement together, little or no agglomeration and the like. The conventional methods for preparing cathode powder generally comprise a sol-gel method, a coprecipitation method, electrostatic spinning, a glycine-nitrate method, a high-temperature solid-phase reaction method and the like, but the problems of difficult dispersion and more agglomeration of powder particles generally exist in the process of preparing the cathode of the cathode powder prepared by the methods, so that the structural uniformity and the performance of the cathode are not ideal. Therefore, there is a need in the art for a method for preparing cathode powder, which is not easy to agglomerate and has good dispersibility in the process of preparing a cathode.
Disclosure of Invention
The invention provides easily dispersible SOFC cathode powder and a preparation method and application thereof, aiming at solving the problems of difficult dispersion and more agglomeration of powder particles commonly existing in the process of preparing a cathode by using the cathode powder prepared by the prior art.
On one hand, the invention provides a preparation method of easily dispersed SOFC cathode powder, which comprises the following steps: mixing nitrate, urea, water-soluble starch and water, and stirring until the nitrate, the urea, the water-soluble starch and the water are completely dissolved to obtain a mixed solution; soaking wood fiber into the mixed solution until the wood fiber is saturated in absorption, so as to obtain saturated wood fiber; and drying the saturated wood fiber, calcining and ball-milling to obtain the readily dispersible SOFC cathode powder.
In some embodiments of the invention, the mixed solution comprises, by weight, 0.1-0.5 parts of water-soluble starch and 70-90 parts of water; the concentration of the nitrate in the mixed solution is not more than 2mol/l, and the mass ratio of the nitrate to the urea is (0.5-1): 1.
In some embodiments of the invention, the nitrate comprises at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, copper nitrate. Preferably, the purity of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate and copper nitrate is more than 99%.
In some embodiments of the invention, it is preferred that the urea has a purity above 99%.
In some embodiments of the invention, the water-soluble starch is a modified starch having carboxyl and hydroxyl groups, and the water-soluble starch has a viscosity of 500 to 1000mpa.s at a concentration of 4wt% and a temperature of 25 ℃.
In some embodiments of the present invention, when preparing the mixed solution, the nitrate and the urea are added into water and stirred to be completely dissolved, and then the water-soluble starch is added and stirred to be completely dissolved, so as to obtain the mixed solution.
In some embodiments of the invention, the wood fibers are spherical wood fibers, which are made from wood fibers by pelletizing.
In some embodiments of the invention, the spherical wood fibers have a diameter of 2 to 5mm and a pore diameter of 10 to 40 μm.
In some embodiments of the invention, the drying temperature of the saturated wood fiber is 80-100 ℃; drying the saturated wood fiber, and then preserving the heat at 350-450 ℃ for 30-60min to finish calcination.
In another aspect, the invention also provides an easily dispersible SOFC cathode powder prepared according to any one of the above preparation methods.
In another aspect, the invention further provides an application of the easily dispersible SOFC cathode powder, in which water is used as a medium, the easily dispersible SOFC cathode powder is ball-milled to obtain SOFC cathode slurry, and the SOFC cathode slurry is loaded on an electrolyte layer to obtain an SOFC cathode.
Compared with the prior art, the invention has the following beneficial effects:
(1) The mixed liquor is formed by mixing nitrate, urea, water-soluble starch and water, the wood fiber is immersed in the mixed liquor until the wood fiber is saturated, the mixed liquor is uniformly immersed in a special porous pore channel of the wood fiber, after the saturated wood fiber is taken out of the mixed liquor, the mixed liquor immersed in the wood fiber is more easily hung in the wood fiber due to the existence of the water-soluble starch, the phenomenon that the mixed liquor is separated from the saturated wood fiber can not occur, the dried saturated wood fiber is still uniformly distributed in the porous pore channel of the wood fiber after the water in the mixed liquor is removed, and the subsequent calcination can be smoothly carried out; nitrate and urea initiate low temperature combustion to generate superfine powder product when calcining, because wood fiber possesses loose porous structure, the heat produced in the combustion reaction can be effectively dissipated when calcining, avoid the crystal grain to grow up, do benefit to the synthesis of nanometer powder, wood fiber and water-soluble starch burning when calcining in addition, become carbon powder after calcining, still evenly distributed in the porous pore canal of wood fiber after the mixed solution removes moisture in the saturation state wood fiber after drying, the residual carbon powder that wood fiber and water-soluble starch burning formed after calcining evenly distributes around the powder granule, effectively keep apart the powder granule, easily disperse among the powder granule when preparing the negative pole, can not produce great aggregate, the cathode structure homogeneity that the preparation obtained is good, the performance is excellent. In addition, the preparation method has the advantages of simple process, safe operation, lower cost and large-scale production, and the prepared cathode powder has uniform microstructure.
(2) The concentration of nitrate in the mixed solution is not more than 2mol/l, and the requirement of the solid oxide fuel cell on the composition of cathode components is met; the mass ratio of nitrate to urea is (0.5-1): 1, which can ensure that the combustion flame temperature of low-temperature combustion reaction generated during calcination is low enough, further ensure that the generated superfine powder has low enough granularity, and meet the requirement of the cathode of the solid oxide fuel cell on the nanometer granularity of the cathode powder; the water-soluble starch accounts for 0.1-0.5 part by weight, so that the mixed solution soaked in the wood fiber can be fully hung in the wood fiber, the phenomenon that the mixed solution is separated from the saturated wood fiber can not occur, and the mixed solution is uniformly distributed in a porous pore channel of the wood fiber after moisture is removed after the subsequent drying; the water accounts for 70-90 parts by weight, and the prepared mixed solution can be ensured to be easily impregnated into the wood fiber.
(3) The water-soluble starch is modified starch with carboxyl and hydroxyl, the water-soluble starch has a viscosity of 500-1000mPa.s measured at a temperature of 25 ℃ and a concentration of 4wt%, and has good solubility in cold water, and the compatibility of wood fiber and mixed solution is realized by the carboxyl and the hydroxyl, namely the modified starch has the carboxyl and the hydroxyl, so that the mixed solution is easier to fix in the wood fiber, the absorption of a porous pore passage of the wood fiber to the mixed solution is facilitated, and the mixed solution is not easy to separate from the wood fiber; in addition, when the mixed solution is prepared, the nitrate and the urea are dissolved in the water, and then the water-soluble starch is added, because the water-soluble starch has certain viscosity, the adding sequence can ensure the dissolving speed of the nitrate, and the starch is prevented from slowing down the dissolving of the nitrate when the starch is added together or added first.
(4) The wood fiber is spherical wood fiber, and in the calcining process, besides the wood fiber with a specific porous pore channel, namely a loose porous structure, heat generated in the combustion reaction during calcining can be effectively dissipated, and a plurality of spherical wood fibers in mutual contact form pore channels between the spherical wood fibers, so that the further dissipation of heat is facilitated, the growth of crystal grains is further avoided, and the synthesis of nano powder is facilitated; the diameter of the spherical wood fiber is 2-5mm, the diameter of the pore canal is 10-40 μm, heat dissipation is facilitated, the mass loss after calcination is 80-90%, namely the carbon powder content left by the combustion of the wood fiber accounts for 10-20% of the mass of the wood fiber, on one hand, powder particles are effectively isolated, on the other hand, the carbon powder can replace a dispersing agent and a pore-forming agent, when cathode slurry is prepared, the dispersing agent and the pore-forming agent are not needed, only water is added into the prepared cathode powder to obtain cathode slurry, and the cathode slurry is loaded on an electrolyte layer to obtain a cathode, so that the process is simple.
(5) According to the invention, after the wood fiber is immersed in the absorption mixed liquor to be saturated, the saturated wood fiber is dried, so that the moisture can be sufficiently removed, and the pore channel of the wood fiber is opened, thereby preventing the problem that the mixed liquor component is brought out of the wood fiber due to the boiling of the moisture caused by direct calcination; drying temperature is 80-100 deg.C to ensure drying efficiency, and calcining at 350-450 deg.C for 30-60min to ensure sufficient combustion of wood fiber and water soluble starch to obtain powder particles separated by carbon powder, i.e. easily dispersible cathode powder.
(6) The cathode powder prepared by the preparation method can be uniformly mixed on the molecular level, the components are more uniform, the particle diameter is small, the wood fiber and the carbon powder remained by the combustion of the water-soluble starch fully isolate the powder particles, and the obtained cathode powder is easy to disperse and cannot generate larger aggregates when a cathode is prepared; in addition, when the cathode powder prepared by the preparation method is applied to preparing a cathode, the carbon powder isolating the powder particles is used as a dispersing agent and a pore-forming agent to play a role, no additional dispersing agent and pore-forming agent are needed, the cathode powder is subjected to ball milling by taking water as a medium, ball milling beads are taken out after the ball milling is finished to obtain SOFC cathode slurry, and the SOFC cathode slurry is loaded on an electrolyte layer to obtain the SOFC cathode.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description of various aspects of the present invention is provided with specific examples, which are only used for illustrating the present invention and do not set any limit to the scope and spirit of the present invention.
The invention provides a preparation method of easily-dispersed SOFC cathode powder, which comprises the following steps: mixing nitrate, urea, water-soluble starch and water, and stirring until the nitrate, the urea, the water-soluble starch and the water are completely dissolved to obtain a mixed solution; soaking the wood fiber into the mixed solution until the wood fiber is saturated in absorption, so as to obtain saturated wood fiber; and drying the saturated wood fiber, calcining and ball-milling to obtain the easily-dispersed SOFC cathode powder.
In the invention, the mixed solution comprises 0.1 to 0.5 portion of water-soluble starch and 70 to 90 portions of water by weight; the concentration of the nitrate in the mixed solution is not more than 2mol/l, and the mass ratio of the nitrate to the urea is (0.5-1): 1.
In the present invention, the nitrate includes at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. Preferably, the purity of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate and copper nitrate is more than 99%.
In the present invention, the urea preferably has a purity of 99% or more.
In the present invention, the water-soluble starch is a modified starch having carboxyl groups and hydroxyl groups, and the water-soluble starch has a viscosity of 500 to 1000mPa.s at a concentration of 4wt% and a temperature of 25 ℃.
In the invention, when preparing the mixed solution, the nitrate and the urea are added into water and stirred until being completely dissolved, and then the water-soluble starch is added and stirred until being completely dissolved, so as to obtain the mixed solution.
In the invention, the wood fiber is spherical wood fiber, and the spherical wood fiber is prepared by granulating the wood fiber. The diameter of the spherical wood fiber is 2-5mm, and the diameter of the pore canal is 10-40 μm.
In the invention, the drying temperature for drying the saturated wood fiber is 80-100 ℃; drying the saturated wood fiber, and then preserving the heat at 350-450 ℃ for 30-60min to finish the calcination.
The invention also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of the invention.
The invention also provides application of the easily dispersible SOFC cathode powder, which is characterized in that water is used as a medium, the easily dispersible SOFC cathode powder is subjected to ball milling to obtain SOFC cathode slurry, and the SOFC cathode slurry is loaded on an electrolyte layer to obtain an SOFC cathode.
Example 1:
the embodiment provides a preparation method of an easily-dispersed SOFC cathode powder, which comprises the following steps:
s1, adding nitrate and urea into 70 parts by weight of distilled water, stirring until the nitrate and the urea are completely dissolved, then gradually adding 0.1 part by weight of water-soluble starch, and stirring for 30min until the water-soluble starch is completely dissolved to obtain a mixed solution; in the step S1, the addition amount of the nitrate is such that the concentration of the nitrate in the prepared mixed solution is 2mol/l, and the addition amount of the urea is such that the mass ratio of the urea to the nitrate is 1;
s2, weighing 10 parts by weight of wood fiber, immersing the wood fiber into the mixed solution for 15min, and screening out the wood fiber absorbing the mixed solution to saturation by using a screen filtering sieve to obtain the saturated wood fiber; in the step S2, after the wood fiber is immersed in the mixed solution, the wood fiber absorbs the mixed solution due to the fact that the wood fiber is provided with porous channels and has a loose and porous structure, the wood fiber can increase weight due to the absorption of the mixed solution, and the saturated state refers to a state reached when the wood fiber does not increase weight any more;
and S3, drying the saturated wood fiber at 80 ℃, calcining the dried wood fiber in a rotary kiln or a roller kiln at 350 ℃ for 30min, and performing ball milling to obtain the readily dispersible SOFC cathode powder.
In this embodiment, the nitrate includes at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. Specifically, the selection of nitrate is determined according to the cathode, for example, in this embodiment, the cathode prepared from the cathode powder is LaFeO 3-δ The nitrate is selected from lanthanum nitrate and ferric nitrate, and the actual dosage of the lanthanum nitrate and the ferric nitrate in the nitrate is determined according to LaFeO 3-δ The stoichiometric ratio of (A) and the concentration of nitrate in the mixed solutionCalculated to be 2 mol/l.
In this example, the water-soluble starch was a modified starch having a carboxyl group and a hydroxyl group, and the viscosity of the water-soluble starch was 500mpa.s at a concentration of 4wt% and a temperature of 25 ℃.
In this example, the wood fibers were spherical wood fibers, which were obtained by granulating wood fibers, and the diameter of the spherical wood fibers was 2mm and the diameter of the pores was 10 μm. In this embodiment, after the spherical wood fiber in the saturated state is dried, when the spherical wood fiber is calcined in a rotary kiln or a roller kiln, the spherical wood fiber can roll in the rotary kiln or the roller kiln, the contact point between adjacent spherical wood fibers is constantly changed, the pore formed between the spherical wood fiber and the spherical wood fiber is constantly changed, a point of constant contact does not exist, and the heat dissipation is facilitated.
This example also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of this example.
This example also provides an application of the easily dispersible SOFC cathode powder of this example, in which the easily dispersible SOFC cathode powder is ball-milled using water as a medium, and the ball-milled beads are taken out after the ball-milling to obtain SOFC cathode slurry (when the cathode powder of this example is made into SOFC cathode slurry, only water is added, and no dispersant or pore-forming agent is added), and the SOFC cathode slurry is supported on an electrolyte layer to obtain an SOFC cathode. In this example, for example, laFeO was obtained 3-δ And a cathode.
Example 2:
the embodiment provides a preparation method of an easily-dispersed SOFC cathode powder, which comprises the following steps:
s1, adding nitrate and urea into 75 parts by weight of distilled water, stirring until the nitrate and the urea are completely dissolved, then gradually adding 0.2 part by weight of water-soluble starch, and stirring for 30min until the water-soluble starch is completely dissolved to obtain a mixed solution; in the step S1, the addition amount of the nitrate is such that the concentration of the nitrate in the prepared mixed solution is 1.5mol/l, and the addition amount of the urea is such that the mass ratio of the urea to the nitrate is 1;
s2, weighing 10 parts by weight of wood fiber, immersing the wood fiber into the mixed solution for 15min, and screening out the wood fiber absorbing the mixed solution to saturation by using a screen filtering sieve to obtain the saturated wood fiber; in the step S2, after the wood fiber is immersed in the mixed solution, the wood fiber absorbs the mixed solution due to the fact that the wood fiber is provided with porous channels and has a loose and porous structure, the wood fiber can increase weight due to the absorption of the mixed solution, and the saturated state refers to a state reached when the wood fiber does not increase weight any more;
and S3, drying the saturated wood fiber at 85 ℃, calcining the dried wood fiber in a rotary kiln or a roller kiln at 370 ℃ for 40min, and performing ball milling to obtain the readily dispersible SOFC cathode powder.
In this embodiment, the nitrate includes at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. Specifically, the nitrate is selected according to the cathode, for example, in this example, the cathode prepared from the cathode powder is Bi 0.5 Sr 0.5 FeO 3-δ The nitrate is selected from bismuth nitrate, strontium nitrate and ferric nitrate, and the actual dosage of the bismuth nitrate, strontium nitrate and ferric nitrate in the nitrate is determined according to Bi 0.5 Sr 0.5 FeO 3-δ The stoichiometric ratio and the concentration of nitrate in the mixed solution are calculated to be 1.5 mol/l.
In this example, the water-soluble starch was a modified starch having a carboxyl group and a hydroxyl group, and the viscosity of the water-soluble starch was 600mpa.s at a concentration of 4wt% and a temperature of 25 ℃.
In this example, the wood fibers were spherical wood fibers, which were obtained by granulating wood fibers, and the diameter of the spherical wood fibers was 3mm and the diameter of the pores was 20 μm. In this embodiment, after the spherical wood fiber of saturation state is dried, when calcining in rotary kiln or roller kiln, spherical wood fiber can roll in rotary kiln or roller kiln, and the contact point between adjacent spherical wood fiber constantly changes, and the pore that forms constantly changes between spherical wood fiber and the spherical wood fiber does not have the point of always contacting, is convenient for thermal scattering and disappearing.
The embodiment also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of the embodiment.
This example also provides an application of the easily dispersible SOFC cathode powder of this example, in which the easily dispersible SOFC cathode powder is ball-milled using water as a medium, and after the ball-milling, the ball-milled beads are removed to obtain an SOFC cathode slurry (when the cathode powder of this example is made into an SOFC cathode slurry, only water is added, and no additional dispersant or pore-forming agent is added), and the SOFC cathode slurry is supported on an electrolyte layer to obtain an SOFC cathode. In this embodiment, for example, bi can be obtained 0.5 Sr 0.5 FeO 3-δ And a cathode.
Example 3:
the embodiment provides a preparation method of an easily-dispersed SOFC cathode powder, which comprises the following steps:
s1, adding nitrate and urea into 80 parts by weight of distilled water, stirring until the nitrate and the urea are completely dissolved, then gradually adding 0.3 part by weight of water-soluble starch, and stirring for 30min until the water-soluble starch is completely dissolved to obtain a mixed solution; in the step S1, the addition amount of the nitrate is such that the concentration of the nitrate in the prepared mixed solution is 1mol/l, and the addition amount of the urea is such that the mass ratio of the urea to the nitrate is 1.7;
s2, weighing 10 parts by weight of wood fibers, soaking the wood fibers in the mixed solution for 15min, and screening out the wood fibers absorbing the mixed solution to saturation by using a screen to obtain saturated wood fibers; in the step S2, after the wood fiber is immersed in the mixed solution, the wood fiber absorbs the mixed solution due to the fact that the wood fiber has porous pores and a loose and porous structure, the weight of the wood fiber is increased due to the absorption of the mixed solution, and the saturated state refers to a state reached when the weight of the wood fiber is not increased;
and S3, drying the saturated wood fiber at 90 ℃, calcining the dried wood fiber in a rotary kiln or a roller kiln at 380 ℃ for 45min, and performing ball milling to obtain the readily dispersible SOFC cathode powder.
In this embodiment, the nitrate includes at least two of lanthanum nitrate, iron nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. In particular, the choice of nitrate is determined by the cathode, e.g., in this embodiment, by the cathodeThe cathode prepared by the powder is La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ The nitrate is selected from lanthanum nitrate, strontium nitrate, cobalt nitrate and ferric nitrate, and the actual dosage of lanthanum nitrate, strontium nitrate, cobalt nitrate and ferric nitrate in the nitrate is determined according to the La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ The stoichiometric ratio and the concentration of nitrate in the mixed solution are calculated to be 1 mol/l.
In this example, the water-soluble starch was a modified starch having a carboxyl group and a hydroxyl group, and the viscosity of the water-soluble starch was 700mpa.s at a concentration of 4wt% and a temperature of 25 ℃.
In this example, the wood fibers were spherical wood fibers, which were obtained by pelletizing wood fibers, and the diameter of the spherical wood fibers was 4mm and the diameter of the pores was 30 μm. In this embodiment, after the spherical wood fiber in the saturated state is dried, when the spherical wood fiber is calcined in a rotary kiln or a roller kiln, the spherical wood fiber can roll in the rotary kiln or the roller kiln, the contact point between adjacent spherical wood fibers is constantly changed, the pore formed between the spherical wood fiber and the spherical wood fiber is constantly changed, a point of constant contact does not exist, and the heat dissipation is facilitated.
The embodiment also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of the embodiment.
This example also provides an application of the easily dispersible SOFC cathode powder of this example, in which the easily dispersible SOFC cathode powder is ball-milled using water as a medium, and the ball-milled beads are taken out after the ball-milling to obtain SOFC cathode slurry (when the cathode powder of this example is made into SOFC cathode slurry, only water is added, and no dispersant or pore-forming agent is added), and the SOFC cathode slurry is supported on an electrolyte layer to obtain an SOFC cathode. In this example, la, for example, was obtained 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ And a cathode.
Example 4:
the embodiment provides a preparation method of an easily-dispersed SOFC cathode powder, which comprises the following steps:
s1, adding nitrate and urea into 85 parts by weight of distilled water, stirring until the nitrate and the urea are completely dissolved, gradually adding 0.4 part by weight of water-soluble starch, and stirring for 30min until the water-soluble starch is completely dissolved to obtain a mixed solution; in the step S1, the addition amount of the nitrate is such that the concentration of the nitrate in the prepared mixed solution is 0.5mol/l, and the addition amount of the urea is such that the mass ratio of the urea to the nitrate is 1;
s2, weighing 10 parts by weight of wood fiber, immersing the wood fiber into the mixed solution for 15min, and screening out the wood fiber absorbing the mixed solution to saturation by using a screen filtering sieve to obtain the saturated wood fiber; in the step S2, after the wood fiber is immersed in the mixed solution, the wood fiber absorbs the mixed solution due to the fact that the wood fiber is provided with porous channels and has a loose and porous structure, the wood fiber can increase weight due to the absorption of the mixed solution, and the saturated state refers to a state reached when the wood fiber does not increase weight any more;
and S3, drying the saturated wood fiber at 95 ℃, calcining the dried wood fiber in a rotary kiln or a roller kiln at 420 ℃ for 50min, and performing ball milling to obtain the readily dispersible SOFC cathode powder.
In this embodiment, the nitrate includes at least two of lanthanum nitrate, iron nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. Specifically, the selection of nitrate is determined according to the cathode, for example, in this example, the cathode pre-prepared from the cathode powder is La 0.8 Be 0.2 Fe 0.6 Ni 0.4 O 3-δ The nitrate is selected from lanthanum nitrate, beryllium nitrate, ferric nitrate and nickel nitrate, and the actual dosage of the lanthanum nitrate, the beryllium nitrate, the ferric nitrate and the nickel nitrate in the nitrate is determined according to the La 0.8 Be 0.2 Fe 0.6 Ni 0.4 O 3-δ The stoichiometric ratio and the concentration of nitrate in the mixed solution are calculated to be 0.5 mol/l.
In this example, the water-soluble starch was a modified starch having carboxyl groups and hydroxyl groups, and the viscosity of the water-soluble starch was 800mPa.s at a concentration of 4wt% and a temperature of 25 ℃.
In this example, the wood fibers were spherical wood fibers, which were obtained by pelletizing the wood fibers, and the diameter of the spherical wood fibers was 4.5mm and the diameter of the pores was 35 μm. In this embodiment, after the spherical wood fiber in the saturated state is dried, when the spherical wood fiber is calcined in a rotary kiln or a roller kiln, the spherical wood fiber can roll in the rotary kiln or the roller kiln, the contact point between adjacent spherical wood fibers is constantly changed, the pore formed between the spherical wood fiber and the spherical wood fiber is constantly changed, a point of constant contact does not exist, and the heat dissipation is facilitated.
This example also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of this example.
This example also provides an application of the easily dispersible SOFC cathode powder of this example, in which the easily dispersible SOFC cathode powder is ball-milled using water as a medium, and the ball-milled beads are taken out after the ball-milling to obtain SOFC cathode slurry (when the cathode powder of this example is made into SOFC cathode slurry, only water is added, and no dispersant or pore-forming agent is added), and the SOFC cathode slurry is supported on an electrolyte layer to obtain an SOFC cathode. In this example, la, for example, was obtained 0.8 Be 0.2 Fe 0.6 Ni 0.4 O 3-δ And a cathode.
Example 5:
the embodiment provides a preparation method of an easily-dispersed SOFC cathode powder, which comprises the following steps:
s1, adding nitrate and urea into 90 parts by weight of distilled water, stirring until the nitrate and the urea are completely dissolved, then gradually adding 0.5 part by weight of water-soluble starch, and stirring for 30min until the water-soluble starch is completely dissolved to obtain a mixed solution; in the step S1, the addition amount of the nitrate is such that the concentration of the nitrate in the prepared mixed solution is 0.2mol/l, and the addition amount of the urea is such that the mass ratio of the urea to the nitrate is 1:1;
s2, weighing 10 parts by weight of wood fiber, immersing the wood fiber into the mixed solution for 15min, and screening out the wood fiber absorbing the mixed solution to saturation by using a screen filtering sieve to obtain the saturated wood fiber; in the step S2, after the wood fiber is immersed in the mixed solution, the wood fiber absorbs the mixed solution due to the fact that the wood fiber is provided with porous channels and has a loose and porous structure, the wood fiber can increase weight due to the absorption of the mixed solution, and the saturated state refers to a state reached when the wood fiber does not increase weight any more;
and S3, drying the saturated wood fiber at 100 ℃, calcining the dried wood fiber in a rotary kiln or a roller kiln at 450 ℃ for 60min, and performing ball milling to obtain the readily dispersible SOFC cathode powder.
In this embodiment, the nitrate includes at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate. Specifically, the selection of nitrate is determined according to the cathode, for example, in this example, the cathode pre-prepared from the cathode powder is La 0.6 Be 0.2 Sr 0.2 Fe 0.8 Cu 0.2 O 3-δ The nitrate is selected from lanthanum nitrate, beryllium nitrate, strontium nitrate, ferric nitrate and cupric nitrate, and the actual dosage of lanthanum nitrate, beryllium nitrate, strontium nitrate, ferric nitrate and cupric nitrate in the nitrate is determined according to La 0.6 Be 0.2 Sr 0.2 Fe 0.8 Cu 0.2 O 3-δ The stoichiometric ratio of (A) and the concentration of nitrate in the mixed solution are calculated to be 0.2 mol/l.
In this example, the water-soluble starch was a modified starch having carboxyl groups and hydroxyl groups, and the viscosity of the water-soluble starch was 1000mPa.s at a concentration of 4wt% and a temperature of 25 ℃.
In this example, the wood fibers were spherical wood fibers, which were obtained by pelletizing wood fibers, and the diameter of the spherical wood fibers was 5mm and the diameter of the pores was 40 μm. In this embodiment, after the spherical wood fiber in the saturated state is dried, when the spherical wood fiber is calcined in a rotary kiln or a roller kiln, the spherical wood fiber can roll in the rotary kiln or the roller kiln, the contact point between adjacent spherical wood fibers is constantly changed, the pore formed between the spherical wood fiber and the spherical wood fiber is constantly changed, a point of constant contact does not exist, and the heat dissipation is facilitated.
The embodiment also provides an easily dispersible SOFC cathode powder prepared according to the preparation method of the embodiment.
This example also provides an application of the easily dispersible SOFC cathode powder of this example, using water as a medium,the SOFC cathode slurry can be obtained by ball-milling the easily dispersible SOFC cathode powder, taking out the ball-milled beads after the ball-milling is completed (when the cathode powder of this example is made into the SOFC cathode slurry, only water is added, and no dispersant or pore-forming agent is added), and supporting the SOFC cathode slurry on the electrolyte layer. In this example, la, for example, was obtained 0.6 Be 0.2 Sr 0.2 Fe 0.8 Cu 0.2 O 3-δ And a cathode.
The present invention has been described in conjunction with specific embodiments which are intended to be exemplary only and not to limit the scope of the invention, which is to be determined by the appended claims. Therefore, various equivalent changes made according to the present invention are still within the scope of the present invention.

Claims (10)

1. The preparation method of the easily-dispersed SOFC cathode powder is characterized by comprising the following steps of:
mixing nitrate, urea, water-soluble starch and water, and stirring until the nitrate, the urea, the water-soluble starch and the water are completely dissolved to obtain a mixed solution;
soaking wood fiber into the mixed solution until the wood fiber is saturated in absorption, so as to obtain saturated wood fiber;
and drying the saturated wood fiber, calcining and ball-milling to obtain the easily-dispersed SOFC cathode powder.
2. The method for preparing the readily dispersible SOFC cathode powder of claim 1, wherein the mixed liquid comprises, by weight, 0.1-0.5 parts water-soluble starch and 70-90 parts water; the concentration of the nitrate in the mixed solution is not more than 2mol/l, and the mass ratio of the nitrate to the urea is (0.5-1): 1.
3. The method for preparing an easily dispersible SOFC cathode powder of claim 1, wherein the nitrate comprises at least two of lanthanum nitrate, ferric nitrate, strontium nitrate, cobalt nitrate, beryllium nitrate, bismuth nitrate, nickel nitrate, and copper nitrate.
4. The method for preparing an easily dispersible SOFC cathode powder according to claim 1, wherein the water-soluble starch is a modified starch having a carboxyl group and a hydroxyl group, and the water-soluble starch has a viscosity of 500 to 1000mpa.s at a concentration of 4wt% and a temperature of 25 ℃.
5. The method for preparing an easily dispersible SOFC cathode powder of claim 1, wherein the mixed solution is obtained by first adding nitrate and urea to water and stirring until the nitrate and urea are completely dissolved, and then adding water-soluble starch and stirring until the water-soluble starch is completely dissolved.
6. The method for preparing the readily dispersible SOFC cathode powder of claim 1, wherein the wood fibers are spherical wood fibers, and wherein the spherical wood fibers are obtained by pelletizing wood fibers.
7. The method for preparing the readily dispersible SOFC cathode powder of claim 6, wherein the spherical wood fibers have a diameter of 2-5mm and a pore diameter of 10-40 μm.
8. The method for preparing an easily dispersible SOFC cathode powder according to claim 1, wherein the saturated wood fiber is dried at a temperature of 80-100 ℃; drying the saturated wood fiber, and then preserving the heat at 350-450 ℃ for 30-60min to finish calcination.
9. An easily dispersible SOFC cathode powder, characterized by being produced by the production method according to any one of claims 1-8.
10. The use of the readily dispersible SOFC cathode powder of claim 9, wherein the readily dispersible SOFC cathode powder is ball milled using water as a medium to obtain an SOFC cathode slurry, and the SOFC cathode slurry is supported on an electrolyte layer to obtain an SOFC cathode.
CN202210926585.4A 2022-08-03 2022-08-03 Easily-dispersible SOFC cathode powder and preparation method and application thereof Pending CN115241477A (en)

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