阅读说明：本技术 一种固体电解质、其制备方法及固体氧化物燃料电池 (Solid electrolyte, preparation method thereof and solid oxide fuel cell ) 是由 李长久 于 2019-11-18 设计创作，主要内容包括：本发明提供了一种固体电解质,具有式1所示化学式：Ti<Sub>x</Sub>M<Sub>y</Sub>Ta<Sub>1-x-y</Sub>O<Sub>5-δ</Sub>式1；其中,M为Fe、Al、Ga、Sn、Co、W、Ce、Mo、La、Y、V或Cr,0.05≤x≤0.30,0.01≤y≤0.20,δ表示因氧空位的产生,氧原子减少的数量。本发明的固体氧化物固体电解质在600～800℃中温范围,有高的氧离子电导率和低的热膨胀系数,室温到800℃的热膨胀系数为1.06～4.48×10<Sup>-6</Sup>/K；在温度和气氛变化时保持性能稳定,内应力小,可应用于中高温条件下氧离子电导的传感器和固体氧化物燃料电池。本发明还提供了一种固体电解质的制备方法和一种固体氧化物燃料电池。(The invention provides a solid electrolyte, which has a chemical formula shown in formula 1: ti x M y Ta 1‑x‑y O 5‑δ Formula 1; wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies. The solid oxide solid electrolyte has high oxygen ion conductivity and low thermal expansion coefficient in the medium temperature range of 600-800 ℃, and the thermal expansion coefficient from room temperature to 800 ℃ is 1.06-4.48 multiplied by 10 ‑6 K; the performance is kept stable when the temperature and the atmosphere change, the internal stress is small, and the method can be applied to sensors of oxygen ion conductance and solid oxide fuel cells under medium-high temperature conditions. The invention also provides a preparation method of the solid electrolyte and a solid oxideA fuel cell.)

1. A solid electrolyte having a chemical formula of formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies.

2. The solid electrolyte according to claim 1, wherein M is Fe, 0.01. ltoreq. y.ltoreq.0.2;

m is Al, and y is more than or equal to 0.01 and less than or equal to 0.20;

m is Ga, and y is more than or equal to 0.01 and less than or equal to 0.20;

m is Cr, and y is more than or equal to 0.01 and less than or equal to 0.20.

3. A method of preparing a solid electrolyte comprising the steps of:

A) mixing Ta powder, Ti powder and M_iO_jDissolving metal powder in hydrofluoric acid, and then mixing the metal powder with an oxalic acid solution to obtain a mixed metal ion solution;

B) titrating an ammonia water solution containing polyethylene glycol into the mixed metal ion solution, carrying out precipitation reaction, and roasting the obtained precipitate to obtain nano mixed powder;

C) sintering the obtained nano mixed powder to obtain a solid electrolyte;

the solid electrolyte has a chemical formula shown in formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies.

4. The method according to claim 3, wherein the oxalic acid solution has a mass concentration of 10 to 15%.

5. The method according to claim 3, wherein the total concentration of the metal particles in the mixed metal ion solution is 0.001 to 0.5 mol/L.

6. The method according to claim 3, wherein the mass fraction of polyethylene glycol in the aqueous ammonia solution is 1 to 5%.

7. The preparation method according to claim 3, wherein the roasting temperature in the step B) is 500-1000 ℃;

the roasting time in the step B) is 1-4 h.

8. The preparation method according to claim 3, wherein the sintering temperature in the step C) is 1400-1600 ℃;

the sintering time is 1-5 hours.

9. The preparation method according to any one of claims 3 to 8, wherein after the mixed nanopowder obtained in step B) is obtained, the mixed nanopowder is mixed with an organic binder, and then dry pressing and forming are carried out to obtain a green body, and then the green body is sintered.

10. A solid oxide fuel cell comprising the solid electrolyte according to any one of claims 1 to 2 or the solid electrolyte obtained by the production method according to any one of claims 3 to 9.

Technical Field

The invention belongs to the technical field of fuel cells, and particularly relates to a solid electrolyte, a preparation method thereof and a solid oxide fuel cell.

Background

The solid electrolyte is used for Solid Oxide Fuel Cells (SOFC), sensors, electrocatalysis, membrane separation, membrane reactors and the like, and has wide application prospects in the fields of energy, metallurgy, chemical industry, environmental protection and the like. The SOFC has high power generation efficiency, wide adaptability to fuel, NO corrosion, full solidification and extremely low NO_XAnd SO_XNoise and dust emissions, etc., are known as green energy sources in the 21 st century. The conventional solid oxide fuel cell uses fluorite-structured yttrium-stabilized zirconia (YSZ) as a solid electrolyte, and the operating temperature thereof must be about 1000 ℃ to achieve a sufficiently high ionic conductivity (about 0.1S/cm),at such high temperatures, the cold-heat cycle performance of the SOFC is reduced and the lifetime is drastically reduced due to the difference in thermal expansion coefficients between the electrolyte, the electrode, and the connecting material and the chemical reaction between the interfaces. If the working temperature of the SOFC can be reduced to 600-800 ℃, the service life of the SOFC can be prolonged by three times, the selection range of electrodes, sealing and connecting materials is increased, the cost of raw materials and manufacture is reduced, and meanwhile, the operation safety of the SOFC is improved.

A.S.Urusova et al studied oxygen-deficient perovskite type BaFe_0.9-xY_0.1Co_xO_3-δPreparation and performance of (a). The perovskite structure can stably exist when the electrolyte with x less than or equal to 0.15 prepared by a sol-gel or solid phase method changes along with the temperature. But the conductivity is relatively low, and the thermal expansion coefficient is high (16-20 multiplied by 10)^-6K^-1) Have limited their application to fuel cells.

The SOFC is an important energy conversion device, and the technical development of the SOFC has important significance for solving the increasingly serious energy crisis current situation. The quality of the solid electrolyte performance of the SOFC core component directly influences the service performance of the fuel cell. Currently, there are four systems for solid electrolyte materials that are more studied: ZrO (ZrO)₂Base, CeO₂Base, Bi₂O₃Radical and LaGaO₃They have limited their use due to their disadvantages, such as low high temperature conductivity, high coefficient of thermal expansion, presence of electronic conduction, high temperature phase transition, and the like.

Disclosure of Invention

The invention aims to provide a solid electrolyte, a preparation method thereof and a solid oxide fuel cell.

The invention provides a solid electrolyte, which has a chemical formula shown in a formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies.

Preferably, M is Fe, and y is more than or equal to 0.01 and less than or equal to 0.2;

m is Al, and y is more than or equal to 0.01 and less than or equal to 0.20;

m is Ga, and y is more than or equal to 0.01 and less than or equal to 0.20;

m is Cr, and y is more than or equal to 0.01 and less than or equal to 0.20.

The invention provides a preparation method of a solid electrolyte, which comprises the following steps:

A) mixing Ta powder, Ti powder and M_iO_jDissolving metal powder in hydrofluoric acid, and then mixing the metal powder with an oxalic acid solution to obtain a mixed metal ion solution;

B) titrating an ammonia water solution containing polyethylene glycol into the mixed metal ion solution, carrying out precipitation reaction, and roasting the obtained precipitate to obtain nano mixed powder;

C) sintering the obtained nano mixed powder to obtain a solid electrolyte;

the solid electrolyte has a chemical formula shown in formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies.

Preferably, the mass concentration of the oxalic acid solution is 10-15%.

Preferably, the total concentration of the metal particles in the mixed metal ion solution is 0.001-0.5 mol/L.

Preferably, in the ammonia water solution, the mass fraction of the polyethylene glycol is 1-5%.

Preferably, the roasting temperature in the step B) is 500-1000 ℃;

the roasting time in the step B) is 1-4 h.

Preferably, the sintering temperature in the step C) is 1400-1600 ℃;

the sintering time is 1-5 hours.

Preferably, after the mixed nano powder in the step B) is obtained, the mixed nano powder is mixed with an organic binder, and is subjected to dry pressing forming to obtain a blank, and then the blank is sintered.

The present invention provides a solid oxide fuel cell characterized by comprising the solid electrolyte described above.

The invention provides a solid electrolyte, which has a chemical formula shown in formula 1: ti_xM_yTa_1-x-yO_5-δFormula 1; wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the number of oxygen atoms reduced due to the generation of oxygen vacancies. The solid oxide solid electrolyte has high oxygen ion conductivity (6.24 multiplied by 10) in the medium temperature range of 600-800 DEG C^-7～2.6×10^-1S/cm) and a low coefficient of thermal expansion, the coefficient of thermal expansion being 1.06-4.48 x 10 at room temperature to 800 DEG C^-6K; the performance is kept stable when the temperature and the atmosphere change, the internal stress is small, and the method can be applied to sensors of oxygen ion conductance and solid oxide fuel cells under medium-high temperature conditions.

The invention also provides a preparation method of the solid electrolyte, and Ta is prepared by adopting an oxalate precipitation method₂O₅、TiO₂And M_iO_jThe nano mixed powder can keep the three metal oxides uniform in microscopic size, reduce sintering temperature and shorten sintering time.

Detailed Description

The invention provides a solid electrolyte, which has a chemical formula shown in formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the reduced number of oxygen atoms due to the generation of oxygen vacancies.

Preferably, 0.06. ltoreq. x.ltoreq.0.25, more preferably, 0.06. ltoreq. x.ltoreq.0.20, in particular, in embodiments of the invention, x is 0.06, 0.10 or 0.20.

Preferably, when M is Fe, 0.01. ltoreq. y.ltoreq.0.20, preferably, 0.02. ltoreq. y.ltoreq.0.15, and in particular, in the examples of the present invention, may be 0.02, 0.08 or 0.15;

m is Al, y is more than or equal to 0.01 and less than or equal to 0.20, preferably, y is more than or equal to 0.02 and less than or equal to 0.15, and specifically, in the embodiment of the invention, the M can be 0.02, 0.04, 0.06, 0.08, 0.10, 0.12 or 0.15;

m is Ga, 0.01-y-0.20, preferably 0.02-y-0.15, and specifically can be 0.02, 0.05, 0.07, 0.10, 0.13 or 0.15 in the embodiment of the invention;

m is Cr, and y is 0.01. ltoreq. y.ltoreq.0.20, preferably 0.02. ltoreq. y.ltoreq.0.15, and specifically, in the embodiment of the present invention, may be 0.02, 0.05, 0.07, 0.10, 0.13 or 0.15.

And M is Sn, Co, W, Ce, Mo, La, Y and V, Y is more than or equal to 0.01 and less than or equal to 0.20, preferably, Y is more than or equal to 0.02 and less than or equal to 0.15.

Specifically, in an embodiment of the present invention, the solid electrolyte has any one of the following chemical formulas: ti_0.06Fe_0.02Ta_0.92O_5-δ、Ti_0.1Fe_0.08Ta_0.82O_5-δ、Ti_0.2Fe_0.15Ta_0.65O_5-δ、Ti_0.06Al_0.02Ta_0.92O_5-δ、Ti_0.08Al_0.04Ta_0.88O_5-δ、Ti_0.1Al_0.06Ta_0.84O_5-δ、Ti_0.12Al_0.08Ta_0.8O_5-δ、Ti_0.014Al_0.1Ta_0.76O_5-δ、Ti_0.17Al_0.12Ta_0.71O_5-δ、Ti_0.2Al_0.15Ta_0.65O_5-δ、Ti_0.6Ga_0.2Ta_0.92O_5-δ、Ti_0.09Ga_0.05Ta_0.86O_5-δ、Ti_0.12Ga_0.07Ta_0.81O_5-δ、Ti_0.15Ga_0.1Ta_0.75O_5-δ、Ti_0.18Ga_0.13Ta_0.69O_5-δ、Ti_0.2Ga_0.15Ta_0.65O_5-δ、Ti_0.6Cr_0.2Ta_0.92O_5-δ、Ti_0.09Cr_0.05Ta_0.86O_5-δ、Ti_0.12Cr_0.07Ta_0.81O_5-δ、Ti_0.18Cr_0.13Ta_0.69O_5-δOr Ti_0.2Cr_0.15Ta_0.65O_5-δ。

The invention also provides a preparation method of the solid electrolyte, which comprises the following steps:

A) mixing Ta powder, Ti powder and M_iO_jDissolving metal powder in hydrofluoric acid, and then mixing the metal powder with an oxalic acid solution to obtain a mixed metal ion solution;

B) titrating an ammonia water solution containing polyethylene glycol into the mixed metal ion solution, carrying out precipitation reaction, and roasting the obtained precipitate to obtain nano mixed powder;

C) sintering the obtained nano mixed powder to obtain a solid electrolyte;

the solid electrolyte has a chemical formula shown in formula 1:

Ti_xM_yTa_1-x-yO_5-δformula 1;

wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the reduced number of oxygen atoms due to the generation of oxygen vacancies.

In the present invention, said M_iO_jPreferably Fe₂O₃、Al₂O₃、Ga₂O₃、SnO₂、Co₂O₃、WO₂、CeO₂、Mo₂O₃、La₂O₃、Y₂O₃、V₂O₅Or Cr₂O₃(ii) a The Ta powder, Ti powder and M_iO_jThe molar amount of the metal powder is determined according to the molar ratio of each element in the chemical formula 1.

In the present invention, the hydrofluoric acid is preferably analytically pure HF in an amount of not less than 0.5L of hydrofluoric acid per mole of sample.

The mass concentration of the oxalic acid solution is preferably 10-15%, and more preferably 12-13%; according to the invention, oxalic acid solution is added into the metal ion solution of the hydrofluoric acid solution to prepare a mixed solution with the metal ion concentration of 0.001-0.5 mol/L, and more preferably 0.005-0.2 mol/L.

After obtaining the mixed metal ion solution, titrating an ammonia water solution containing polyethylene glycol into the mixed metal ion solution, and carrying out precipitation reaction to obtain a precipitate, wherein preferably, in the titration process, the titration speed is controlled, and mechanical stirring is carried out simultaneously to keep the pH of the solution to be more than or equal to 11; during the titration a suspension is formed, preferably by ultrasonic dispersion.

In the invention, the mass concentration of polyethylene glycol in the ammonia water is preferably 1-3%; the polyethylene glycol is used as a dispersing agent, preferably PEG10000, the dosage of the ammonia water solution of the polyethylene glycol is not particularly limited, and the titration is carried out until no precipitate is generated.

After titration is carried out until no precipitate is generated, filtering is carried out to obtain a precipitate, the precipitate is preferably washed by deionized water, then dehydrated by absolute ethyl alcohol, and then dried and roasted to obtain the nano mixed powder.

In the invention, the drying temperature is preferably 70-90 ℃, more preferably 75-85 ℃, and most preferably 80 ℃; the drying time is preferably 12 to 24 hours, and more preferably 15 to 20 hours.

The roasting temperature is preferably 500-1000 ℃, more preferably 600-900 ℃, and most preferably 650-850 ℃; the roasting time is preferably 1-4 h.

After the nano mixed powder is obtained, the powder is preferably mixed with the organic binder, and the mixture is subjected to dry pressing, demolding and drying to obtain a blank.

In the invention, the organic binder is preferably a polyvinyl alcohol organic binder, and the mass fraction of the organic binder is preferably 2-8%, and more preferably 3-7%; the pressure of the dry pressing molding is preferably more than 100 MPa; the drying temperature after demolding is preferably 80-100 ℃.

After the green body is obtained, the green body is sintered to obtain the solid electrolyte, the green body is preferably sintered under neutral and oxidizing atmosphere, and the sintering is preferably pressureless sintering.

The sintering temperature is preferably 1400-1700 ℃, and more preferably 1500-1600 ℃; the sintering time is preferably 1 to 5 hours, and more preferably 2 to 4 hours. In the pressureless reaction sintering process of the present invention, Ta₂O₅And a dopant TiO₂And M_iO_jSolid phase reaction is carried out to generate solid solution, and nanocrystalline TiO is prepared₂And M_iO_jDoped Ta₂O₅A solid electrolyte of a oxygen ion conductor.

The present invention also provides a solid oxide fuel cell comprising the solid electrolyte described above. The invention is not limited to the anode, cathode and other components of the fuel cell, and the anode, cathode and other components of the fuel cell commonly used in the art may be used.

The invention provides a solid electrolyte, which has a chemical formula shown in formula 1: ti_xM_yTa_1-x-yO_5-δFormula 1; wherein M is Fe, Al, Ga, Sn, Co, W, Ce, Mo, La, Y, V or Cr, x is more than or equal to 0.05 and less than or equal to 0.30, Y is more than or equal to 0.01 and less than or equal to 0.20, and delta represents the reduced number of oxygen atoms due to the generation of oxygen vacancies. The solid oxide solid electrolyte has high oxygen ion conductivity (6.24 multiplied by 10) in the medium temperature range of 600-800 DEG C^-7～2.6×10^-1S/cm) and a low coefficient of thermal expansion, the coefficient of thermal expansion from room temperature to 830 ℃ being 1.06-4.48X 10^-6K; the performance is kept stable when the temperature and the atmosphere change, the internal stress is small, and the method can be applied to sensors of oxygen ion conductance and solid oxide fuel cells under medium-high temperature conditions.

The invention also provides a preparation method of the solid electrolyte, and Ta is prepared by adopting an oxalate precipitation method₂O₅、TiO₂And M_xO_yMixing the powder to obtain three metal oxidesThe micro-size is kept uniform, the sintering temperature is reduced, and the sintering time is reduced.

In order to further illustrate the present invention, the following examples are provided to describe the solid electrolyte, the preparation method thereof and the solid oxide fuel cell in detail, but should not be construed as limiting the scope of the present invention.