A pyrochlore samarium stannate-based composite anode material for direct ammonia solid oxide fuel cells and its application

Abstract

The present invention discloses a pyrochlore samarium stannate-based composite anode material for a direct ammonia solid oxide fuel cell and its application. The chemical formula of the pyrochlore samarium stannate-based anode material is Sm 2‑ x Sr x Sn 2‑y Ni y O 7+δ , where (0 < x ≤ 0.2, 0 < y ≤ 0.25, 0 < δ < 1). The synthesized anode material can be mixed and ground with a solid electrolyte, ethyl cellulose, and terpineol to obtain a slurry, which is brushed on a YSZ electrolyte support sheet to obtain a single cell sheet. The anode material has a high conductivity at medium and low temperatures, and the prepared solid oxide fuel cell has good performance and good stability.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of anode materials for solid oxide fuel cells, and particularly relates to a preparation method and application of a pyrochlore samarium stannate-based oxide and solid electrolyte composite anode material. Background Art

[0002] As a new type of all-solid-state clean power generation device, a fuel cell is a power generation technology with great development prospects. It is not restricted by the Carnot cycle, avoids energy loss during multiple transmission processes, and effectively recovers the heat generated during the reaction process to improve the overall efficiency of the system. A solid oxide fuel cell (SOFC) has a relatively high energy conversion rate among various fuel cells. It mainly consists of an electrolyte, a cathode, and an anode, and the operating temperature is generally 600 - 1000 °C. Compared with other fuel cells, the electrolyte of SOFC is solid, so there is no problem of electrolyte evaporation and leakage, and problems such as electrode corrosion in acid-base electrolytes are also avoided, with a long service life; there is no need to use precious metals as catalysts; the energy and fuel utilization rates are high. Therefore, the application scope of SOFC almost covers all traditional power markets, portable power sources, mobile power sources, etc. However, the too high operating temperature of SOFC also restricts its large-scale development and application, and there is an urgent need to find electrode materials that can adapt to high-temperature environments. The anode material of SOFC is a key component affecting the battery performance. It needs to have good chemical stability at high temperatures, ensure good thermal expansion coefficient matching with the electrolyte and other materials, have good catalytic and gas permeability, and also have a certain mechanical strength for easy processing and production.

[0003] CN100583516C discloses the preparation and application of a strontium titanate anode material. The La doped at the A site and Sc doped at the B site in the perovskite-type oxide SrTiO 3 forms the La 0.3 Sr 0.7 Sc x Ti 1-x O 3-δ anode material, and the prepared anode material has good chemical compatibility with the LSGM electrolyte. At 800 °C, the ionic conductivity of La 0.3 Sr 0.7 Sc 0.1 Ti 0.9 O 3-δ is 0.0095 S·cm -1 , which can greatly improve the working performance of SOFC. However, compared with the traditional Ni-based anode material, the conductivity of the material is still very low and needs to be further improved.

[0004] CN102054992A discloses a double perovskite anode material with high electrical conductivity and its preparation method. By doping Co at the B site of the double perovskite oxide Sr 2 MgMoO 6 to form Sr 2 Mg 1-x Co x MoO 6 anode material, the electrical conductivity of the doped material is increased by 13.5 times compared with that before doping. At the same time, the prepared porous Sr 2 Mg 1-x Co x MoO 6 has good strength, good chemical compatibility with GDC and LSGM, and good anti-carbon deposition and sulfur poisoning resistance. However, with the operation of the battery, Mo will transfer to the electrolyte, resulting in a decrease in the electrical conductivity of the material.

[0005] CN111883789A discloses an electrode material for a solid oxide fuel cell, its preparation method and application. The chemical formula of the anode material is Gd 2 SrCo x Fe 2-x O 7-δ . This material can precipitate uniformly distributed Co-Fe nano-alloy particles in a reducing atmosphere, has good electrical conductivity and catalytic activity, and has a low polarization resistance. This material is not prone to carbon deposition when using hydrocarbons as fuel and has good stability.

[0006] The anode materials used in the SOFCs reported above have problems such as low output performance of the battery, high material cost, complex preparation process, and poor battery stability. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides the preparation and application of a pyrochlore samarium stannate-based oxide anode material for medium and low temperature SOFCs, realizing good electrochemical performance of SOFCs at medium and low temperatures (600 - 800 °C). Using hydrothermal synthesis technology to prepare a Sm 2-x Sr x Sn 2-y Ni y O 7+δ anode material with a pyrochlore structure, the preparation method is simple, the raw materials are inexpensive, and the prepared anode material has good chemical compatibility with the electrolyte material, and has good conduction performance and good ionic conductivity at medium and low temperatures.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A pyrochlore samarium stannate-based composite anode material for a direct ammonia solid oxide fuel cell. The composite anode material is composed of 40-90% by mass of a pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ and 10-60% by mass of a solid electrolyte, and the sum of the mass fractions of the two is 100%; wherein, 0 < x ≤ 0.2, 0 < y ≤ 0.25, 0 < δ < 1.

[0010] Furthermore, the preparation method of the pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ comprises the following steps:

[0011] 1) Weigh 16.00-17.78 g of Sm(NO 3 ) 3 ·6H 2 O, 0.01-0.85 g of Sr(NO 3 ) 2 , 8.59-14.02 g of a tin salt, and 0.29-1.45 g of a nickel salt according to the stoichiometric ratio, dissolve them uniformly in 200-400 ml of an organic solvent by stirring to obtain solution A;

[0012] 2) Add an alkali solution to solution A to adjust the pH value to 9-11, and continuously stir to obtain solution B;

[0013] 3) Pour solution B into the inner liner of a hydrothermal reaction kettle, and then place the reaction kettle in a drying oven at 50-120 °C for hydrothermal reaction for 12-24 h;

[0014] 4) Centrifuge the reacted solution;

[0015] 5) After drying the centrifuged solution in a drying oven, grind and calcine it to obtain the pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ powder.

[0016] Furthermore, the nickel salt in step 1) is one or more of nickel chloride, nickel sulfate, nickel nitrate, and nickel acetate; the tin salt is one or more of stannic chloride pentahydrate, stannous sulfate, and tin methanesulfonate; the organic solvent is one or more of ethanol, acetone, carbon tetrachloride, benzene, and toluene.

[0017] Further, the alkali solution described in step 2) is one or more of sodium hydroxide, urea, ammonia water, ammonium bicarbonate, ammonium carbonate, sodium carbonate, and sodium bicarbonate.

[0018] Further, the rate of the centrifugation treatment described in step 4) is specifically 3000 - 6000 r / min, and the centrifugation time is 3 - 6 min.

[0019] Further, the drying temperature in step 5) is 80 - 120 °C, the drying time is 12 - 18 h, the calcination temperature is 1000 - 1400 °C, and the calcination time is 2 - 6 h.

[0020] Further, the solid electrolyte material is ZrO doped with 5 - 10 mol% Y 2 O 3 stabilized, La 2 Sr 0.8 Ga 0.2 Mg 0.8 O 0.2 O 3-δ BaZr 0.1 Ce 0.7 Y 0.2 O 2 one or more of.

[0021] Further, the preparation method of the pyrochlore samarium stannate - based composite anode material includes: putting the pyrochlore samarium stannate - based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ anode powder and the solid electrolyte powder into an agate mortar, and hand - grinding for 1 - 2 h to mix them evenly to obtain the composite anode material.

[0022] Further, the application of the pyrochlore samarium stannate - based composite anode material includes the following steps: adding a terpineol solution containing ethyl cellulose to the pyrochlore samarium stannate - based composite anode powder, grinding evenly to prepare an anode slurry; brushing the anode slurry on one side of a YSZ electrolyte support sheet by screen - printing, sintering at a high temperature, taking it out and brushing an LSM cathode slurry on the other side of the YSZ electrolyte support sheet, and then sintering at 1100 °C for 2 - 4 h to obtain a single - cell sheet.

[0023] Further, the content of ethyl cellulose in the terpineol solution is 1 - 8 wt%, the calcination temperature after brushing the anode slurry is 1000 - 1400 °C, the heating rate is 2 - 10 °C / min, and the calcination time is 2 - 6 h.

[0024] Further, the Sm described in step 1) 2-x Sr x Sn2-y Ni y O 7+δ The introduction method of Ni substance in the anode material can also be: taking Sm 2-x Sr x Sn 2 O 7+δ (0 < x ≤ 0.2, 0 < δ < 1) anode material as a reference, printing NiO on the anode side, impregnating nickel salt, and mechanically mixing NiO with the anode material and the solid electrolyte material by a ball mill in one or more of them; wherein the impregnation concentration of nickel salt on the anode side is 1-10 wt%, and the molar ratio of NiO, anode material, and solid electrolyte material is (1-6):(2-6):(2-6); the speed of the ball mill is 250-400 r / min, and the ball milling time is 10-24 h.

[0025] Further, the specific operation method of printing NiO on the anode side includes: first, brush the anode material on one side of the YSZ electrolyte support sheet by screen printing, after drying at 60 °C, then brush a layer of NiO slurry, and finally bake at 1000-1400 °C for 2-6 h. After taking out, brush the LSM cathode slurry on the other side of the YSZ electrolyte support sheet, and then sinter at 1100 °C for 2-4 h to obtain a single cell; the specific operation method of impregnating nickel salt is, after the anode slurry is brushed, repeatedly drop the nickel salt solution. After each layer is added, keep it warm in a tube furnace at 400-600 °C for 2 h until the concentration of nickel salt reaches the required value (1-10 wt%).

[0026] The remarkable advantages of the present invention are as follows:

[0027] 1. The present invention provides a novel Sm anode material with a pyrochlore structure 2-x Sr x Sn 2-y Ni y O 7+δ By mixing the anode material and the solid electrolyte material, the anode reaction area is increased, and the battery output performance is improved.

[0028] 2. There are a certain number of oxygen vacancies in the anode material. Some oxygen ions can migrate to occupy the hole positions, generating ionic conduction. In addition, since the pyrochlore structure is an open structure, doping with other ions can also provide holes for the migration of oxygen atoms, protons or electrons, thereby improving the ionic conduction ability.

[0029] 3. The thermal expansion coefficient of this material matches that of the traditional electrolyte material, and the long-term stable operation of the battery can be maintained.

[0030] 4. Among different Ni introduction methods, the single cell obtained by impregnating nickel salt on the anode material has the optimal power density at 800 °C. This is because finer nickel particles will be obtained after high-temperature calcination of the impregnated nickel salt, which are evenly distributed in the porous anode, improving the performance of the single cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is Sm 2-x Sr x Sn 2 O 7+δ (0 < x ≤ 0.2, 0 < δ < 1) XRD pattern of the sample of the anode material after calcination at 1200 °C for 2 h.

[0032] Figure 2 is Sm 2-x Sr x Sn 2-y Ni y O 7+δ (0 < x ≤ 0.2, 0 < y ≤ 0.25, 0 < δ < 1) XRD pattern of the sample of the anode material after calcination at 1200 °C for 2 h. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following examples are listed to further illustrate the present invention.

[0034] Example 1

[0035] Sm 2-x Sr x Sn 2 O 7+δ Preparation of a composite anode material and its single cell composed with a solid electrolyte:

[0036] (1) Weigh 16.00 g of Sm(NO 3 ) 3 ·6H 2 O, 0.22 g of Sr(NO 3 ) 2 and 14.02 g of SnCl 4 ·5H 2 O and dissolve them in 200 ml of ethanol and stir evenly to obtain solution A;

[0037] (2) Add urea solution to solution A to adjust the pH value to 9 and keep stirring to obtain solution B;

[0038] (3) Pour solution B into the inner liner of the hydrothermal reaction kettle, and then place the reaction kettle in a drying oven at 120 °C for hydrothermal reaction for 12 h;

[0039] (4) Place the reacted solution in a centrifuge and centrifuge it at a rate of 3000 r / min for 3 min;

[0040] (5) After centrifuging the solution, it is dried in an oven at 120 °C for 12 h, ground, and then calcined at 1200 °C for 2 h to obtain the pyrochlore stannate lanthanum-based oxide Sm 1.95 Sr 0.05 Sn 2 O 7+δ powder.

[0041] (6) Using 60 wt% of Sm 1.95 Sr 0.05 Sn 2 O 7+δ anode phase and 40 wt% of 8 mol% Y 2 O 3 -stabilized ZrO 2 (YSZ) solid electrolyte phase, the composite anode material is prepared and ground in an agate mortar for 2 h to obtain the composite anode powder;

[0042] (7) Add a terpineol solution containing 6 wt% ethyl cellulose to the composite anode powder, mix and grind evenly to obtain the composite anode slurry;

[0043] (8) Brush the anode slurry on one side of the YSZ electrolyte support sheet by screen printing, sinter at 1200 °C for 2 h, take it out, brush the LSM cathode slurry on the other side of the YSZ electrolyte support sheet, and then place it in a high-temperature furnace and sinter at 1200 °C for 2 h to obtain the single cell sheet.

[0044] Example 2

[0045] The specific preparation method of this example is basically the same as that of Example 1, except that the pyrochlore structure oxide is Sm 2 Sn 2 O 7 (i.e., x = 0), that is, Sr(NO 3 ) 2 is not added to the raw materials in step (1).

[0046] Example 3

[0047] The specific preparation method of this example is basically the same as that of Example 1, except that by adjusting the dosage of the raw materials in step (1), the pyrochlore structure oxide is Sm 1.8 Sr 0.2 Sn 2 O 7 (i.e., x = 0.2).

[0048] Example 4

[0049] The specific preparation method of this example is basically the same as that of Example 1, except that in step (2), the alkaline solution is changed to sodium hydroxide solution and the pH value is adjusted to 10.

[0050] Example 5

[0051] The specific preparation method of this example is basically the same as that of Example 1, except that in step (2), the alkaline solution is changed to sodium hydroxide solution and the pH value is adjusted to 11.

[0052] Example 6

[0053] The specific preparation method of this example is basically the same as that of Example 1, except that in steps (5) and (8), the calcination temperature is changed to 1000 °C.

[0054] Example 7

[0055] The specific preparation method of this example is basically the same as that of Example 1, except that in steps (5) and (8), the calcination temperature is changed to 1100 °C.

[0056] Example 8

[0057] The specific preparation method of this example is basically the same as that of Example 1, except that in steps (5) and (8), the calcination temperature is changed to 1400 °C.

[0058] Example 9

[0059] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the proportion of Sm 1.95 Sr 0.05 Sn 2 O 7+δ is changed from 60 wt% to 50 wt%, and the proportion of YSZ is changed from 40 wt% to 50 wt%.

[0060] Example 10

[0061] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the proportion of Sm 1.95 Sr 0.05 Sn 2 O 7+δ is changed from 60 wt% to 80 wt%, and the proportion of YSZ is changed from 40 wt% to 20 wt%.

[0062] Example 11

[0063] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the proportion of Sm 1.95 Sr 0.05 Sn 2 O7+δ The proportion of [substance] is changed from 60 wt% to 90 wt%, and the proportion of YSZ is changed from 40 wt% to 10 wt%.

[0064] Example 12

[0065] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the solid electrolyte is changed from YSZ to BaZr 0.1 Ce 0.7 Y 0.2 O 2 .

[0066] Example 13

[0067] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the solid electrolyte is changed from YSZ to La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ .

[0068] Example 14

[0069] The specific preparation method of this example is basically the same as that of Example 1, except that in step (7), the content of ethyl cellulose is changed to 4 wt%.

[0070] Example 15

[0071] The specific preparation method of this example is basically the same as that of Example 1, except that in step (1), 0.22 g of Ni(NO 3 ) 2 ·6H 2 O is also added to the raw materials, and the mass of SnCl 4 ·5H 2 O is changed to 13.67 g (i.e., n Sm :n Sr :n Sn :n Ni = 1.95:0.05:1.95:0.05), and the pyrochlore structure oxide Sm 1.95 Sr 0.05 Sn 1.95 Ni 0.05 O 7 is prepared.

[0072] Example 16

[0073] The specific preparation method of this example is basically the same as that of Example 1, except that in step (1), 0.87 g of Ni(NO 3 ) 2 ·6H2 O, change the mass of SnCl 4 ·5H 2 O to 12.97 g (i.e., n Sm :n Sr :n Sn :n Ni = 1.95:0.05:1.85:0.15), and prepare the pyrochlore - structured oxide Sm 1.95 Sr 0.05 Sn 1.85 Ni 0.15 O 7 .

[0074] Example 17

[0075] The specific preparation method of this example is basically the same as that of Example 1, except that in step (1), 1.45 g of Ni(NO 3 ) 2 ·6H 2 O is also added, and change the mass of SnCl 4 ·5H 2 O to 12.27 g (i.e., n Sm :n Sr :n Zr :n Ni = 1.95:0.05:1.75:0.25), and prepare the pyrochlore - structured oxide Sm 1.95 Sr 0.05 Sn 1.75 Ni 0.25 O 7 .

[0076] Example 18

[0077] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the composite anode powder is changed to 20 wt% of Sm 1.95 Sr 0.05 Sn 2 O 7 anode phase, 20 wt% of NiO powder and 60 wt% of 8 mol% Y 2 O 3 stabilized ZrO 2 (YSZ) solid electrolyte phase.

[0078] Example 19

[0079] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the composite anode powder is changed to 30 wt% of Sm 1.95 Sr 0.05 Sn 2 O7 Anode phase, 30 wt% NiO powder, and 40 wt% 8 mol% Y 2 O 3 Stabilized ZrO 2 (YSZ) solid electrolyte phase.

[0080] Example 20

[0081] The specific preparation method of this example is basically the same as that of Example 1, except that in step (6), the composite anode powder is 40 wt% Sm 1.95 Sr 0.05 Sn 2 O 7 Anode phase, 40 wt% NiO powder, and 20 wt% 8 mol% Y 2 O 3 Stabilized ZrO 2 (YSZ) solid electrolyte phase.

[0082] Example 21

[0083] The specific preparation method of this example is basically the same as that of Example 1, except that in step (8), after brushing the anode, it is impregnated with a 1 wt% C 4 H 6 NiO 4 ·4H 2 O solution. The specific operation method for impregnating the nickel salt is as follows: after the anode slurry is brushed, the nickel salt solution is added dropwise multiple times. After each layer is added, it is kept warm in a tube furnace at 450 °C for 2 h until the concentration of the nickel salt reaches the required 1 wt% requirement.

[0084] Example 22

[0085] Sm 2-x Sr x Sn 2 O 7+δ Preparation of a composite anode material composed of and a solid electrolyte and its single cell:

[0086] (1) Weigh 16.00 g Sm(NO 3 ) 3 ·6H 2 O, 0.22 g Sr(NO 3 ) 2 and 14.02 g SnCl 4 ·5H 2 O and dissolve them in 200 ml of ethanol and stir evenly to obtain solution A;

[0087] (2) Add urea solution to solution A to adjust the pH value to 9 and keep stirring to obtain solution B;

[0088] (3) Pour solution B into the inner liner of the hydrothermal reactor, and then place the reactor in a drying oven at 120 °C for hydrothermal reaction for 12 h;

[0089] (4) Place the reacted solution in a centrifuge and centrifuge it at a rate of 3000 r / min for 3 min;

[0090] (5) After placing the centrifuged solution in a drying oven at 120 °C for drying for 12 h, grind it and then calcine it at 1200 °C for 2 h to obtain lanthanum pyrochlore stannate-based oxide Sm 1.95 Sr 0.05 Sn 2 O 7+δ powder.

[0091] (6) Prepare a composite anode material with 60 wt% of Sm 1.95 Sr 0.05 Sn 2 O 7+δ anode phase and 40 wt% of 8 mol% Y 2 O 3 stabilized ZrO 2 (YSZ) solid electrolyte phase, put it into an agate mortar and grind it for 2 h to obtain composite anode powder;

[0092] (7) Add a terpineol solution containing 6 wt% ethyl cellulose to the composite anode powder, mix and grind evenly to obtain a composite anode slurry;

[0093] (8) Brush the composite anode slurry on one side of the YSZ electrolyte support sheet by screen printing method, sinter it at 1200 °C for 2 h, and then repeatedly drop nickel acetate tetrahydrate (C 4 H 6 NiO 4 ·4H 2 O) solution on the anode. After each layer is dropped, keep it warm in a tubular furnace at 450 °C for 2 h until the content of C 4 H 6 NiO 4 ·4H 2 O reaches the requirement of 5 wt% of the anode material (composite anode powder) brushed on the YSZ electrolyte support sheet; after taking it out, brush the LSM cathode slurry on the other side of the YSZ electrolyte support sheet, and then place it in a high-temperature furnace and sinter it at 1200 °C for 2 h to obtain a single cell.

[0094] Example 23

[0095] The specific preparation method of this example is basically the same as that of Example 1, the difference is that after brushing the anode in step (8), it is impregnated with 10 wt% of C 4 H 6 NiO4 ·4H 2 O solution. The specific operation method for impregnating the nickel salt is as follows: after the anode slurry is brushed, the nickel salt solution is dropped repeatedly. After each layer is dropped, it is kept warm in a tube furnace at 450 °C for 2 h until the concentration of the nickel salt reaches the required 10 wt%.

[0096] Product performance test:

[0097] Before the fuel cell is assembled, a thin layer of silver paste needs to be evenly screen-printed on the cathode of the single cell to play a current collection role during the test.

[0098] For the assembly of the fuel cell, first place a platinum wire (diameter 0.5 mm, length 50 mm) and a nickel mesh (diameter 15 mm) on the corundum tube of the test device. Then place the anode side of the single cell to be tested on the nickel mesh to ensure that the anode contacts the fuel gas, and the cathode contacts the air. The middle part is sealed with a high-temperature ceramic adhesive. Finally, add a silver mesh and a platinum wire on the cathode, and use platinum paste to tightly connect the platinum wire and the electrode material. After the ceramic adhesive is sealed, test with high-purity (99.999%) ammonia gas as the fuel gas. In this test, the Zahner IM6 electrochemical workstation is used for power density.

[0099] Table 1 Electrochemical performance of different anodic composites of direct ammonia solid oxide fuel cells at 800 °C

[0100]

[0101]

[0102] As can be seen from Table 1, when impregnating 5 wt% C 1.95 Sr 0.05 Sn 2 O 7 -40 wt% 8YSZ anode material with 4 H 6 NiO 4 ·4H 2 O, the maximum power density of the battery at 800 °C can reach 386 mW·cm -2 , which is 3.6 times that of using Sm 1.95 Sr 0.05 Sn 2 O 7 -40 wt% BaZr 0.1 Ce 0.7 Y 0.2 O 2 (the maximum power density at 800 °C is 108 mW·cm -2 ) as the anode material.

[0103] Appropriate Ni introduction can improve battery performance. When performing B-site Ni doping, when the doping amount of Ni is 0.29 g, the battery performance is the best, and the maximum power density at this time is 347 mW·cm -2 ; When ball-milling and mixing the anode material with NiO and YSZ, when the ratio of the three is 3:3:4, the maximum power density of the single cell can reach 356 mW·cm -2 ; Compared with B-site Ni doping and mechanical mixing of the anode material with NiO, when 5 wt% C 4 H 6 NiO 4 ·4H 2 O is impregnated on the anode material, the power density of the single cell reaches the optimum, and the maximum power density of the single cell is 386 mW·cm -2 .

[0104] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A pyrochlore samarium stannate-based composite anode material for direct ammonia solid oxide fuel cells, Characterized in that: The composite anode material described above consists of pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ and a solid electrolyte with a mass fraction of 10% to 60%, and the sum of the mass fractions of the two is 100%; where 0 < x ≤ 0.2, 0 < y ≤ 0.25, 0 < δ < 1; The described preparation method of pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ comprises the following steps: 1) Weigh 16.00 - 17.78 g of Sm(NO 3 ) 3 •6H 2 O, 0.01 - 0.85 g of Sr(NO 3 ) 2 , 8.59 - 14.02 g of stannous salt and 0.29 - 1.45 g of nickel salt and dissolve them evenly in 200 - 400 ml of organic solvent by stirring to obtain solution A; 2) Add an alkali solution to solution A to adjust the pH value to 9-11, and continuously stir to obtain solution B; 3) Pour solution B into the inner liner of a hydrothermal reaction kettle, and then place the reaction kettle in a drying oven at 50-120 °C for hydrothermal reaction for 12-24 h; 4) Centrifuge the reacted solution in a centrifuge; 5) After centrifuging the solution, place it in a drying oven to dry, then grind and calcine to obtain pyrochlore samarium stannate-based oxide Sm 2- x Sr x Sn 2-y Ni y O 7+δ powder.

2. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The nickel salt described in step 1) is one or more of nickel chloride, nickel sulfate, nickel nitrate, and nickel acetate; the tin salt is one or more of tin tetrachloride pentahydrate, stannous sulfate, and tin methanesulfonate; the organic solvent is one or more of ethanol, acetone, carbon tetrachloride, benzene, and toluene.

3. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The alkali solution described in step 2) is one or more of sodium hydroxide, urea, ammonia water, ammonium bicarbonate, ammonium carbonate, sodium carbonate, and sodium bicarbonate solutions.

4. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The rate of the centrifugation treatment described in step 4) is specifically 3000-6000 r / min, and the centrifugation time is 3-6 min.

5. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The drying temperature in step 5) is 80-120 °C, the drying time is 12-18 h, the calcination temperature is 1000-1400 °C, and the calcination time is 2-6 h.

6. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The solid electrolyte is Y-doped ZrO₂ with a doping amount of 5-10 mol% 2 O 3 stabilized ZrO 2 、La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ 、BaZr 0.1 Ce 0.7 Y 0.2 O 2 or one or more of them.

7. The pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: The preparation method of the pyrochlore samarium stannate-based composite anode material includes: putting the pyrochlore samarium stannate-based oxide Sm 2-x Sr x Sn 2-y Ni y O 7+δ anode powder and the solid electrolyte powder into an agate mortar, and hand-milling for 1 - 2 h to make them uniformly mixed, thereby obtaining the composite anode material.

8. The application of the pyrochlore samarium stannate-based composite anode material according to claim 1, Characterized in that: Comprises the following steps: Add a terpineol solution containing ethyl cellulose to the pyrochlore samarium stannate-based composite anode powder, grind evenly to obtain an anode paste; brush the anode paste on one side of a YSZ electrolyte support sheet by screen printing, sinter at a high temperature, take it out and brush the LSM cathode paste on the other side of the YSZ electrolyte support sheet, and then sinter at 1100 °C for 2-4 h to obtain a single cell sheet.

9. The application according to claim 8, Characterized in that: The content of ethyl cellulose in the terpineol solution is 1-8 wt%, the calcination temperature after brushing the anode paste is 1000-1400 °C, the heating rate is 2-10 °C / min, and the calcination time is 2-6 h.

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