High-toughness anode support body and preparation method and application thereof

Abstract

The invention relates to the technical field of batteries, and discloses a high-toughness anode support and a preparation method and application thereof. The preparation method of the high-toughness anode support comprises the following steps: mixing nickel oxide, electrolyte powder, starch and rare earth aluminate, and carrying out ball milling treatment to obtain anode powder; anode powder is pressed by adopting a dry pressing method to obtain an anode support body green sheet, and the high-toughness anode support body is obtained after high-temperature calcination. The ferroelastic domain converted rare earth aluminate is added into the anode support body, so that the mechanical strength and the fracture toughness of the anode support body are remarkably improved, the fracture toughness of the cell is improved, and the electrochemical performance and the catalytic activity of the anode of the proton conductor fuel cell are maintained; and the integrity of the whole battery structure and the performance reliability of the electric pile are ensured.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a high-toughness anode support and a preparation method and application thereof. Background Art

[0002] Protonic Ceramic Fuel Cell (PCFC) is a solid oxide fuel cell with proton conductor as electrolyte. It has the advantages of good environmental effect, high energy conversion efficiency, strong fuel adaptability and suitability for medium and low temperature. It has broad application prospects in large-scale centralized power supply, distributed power generation, household combined heat and power system, and ship vehicle power supply. Generally, the flat anode supported proton ceramic fuel cell is the main one, and the battery structure is mainly composed of anode support layer, electrolyte layer, cathode layer, etc. Among them, the anode support layer has the largest thickness, and its mechanical strength determines the overall mechanical strength of the battery cell. Improving the mechanical strength of the anode support is very important to ensure the overall strength and life of the proton ceramic fuel cell. Among various mechanical properties, fracture toughness is one of the important parameters of the anode support ceramic material, which represents the ability of the material to resist crack propagation.

[0003] However, cracks or even fractures often occur in the support layer during the assembly and operation of the fuel cell stack: in a high temperature environment, the thermal expansion coefficient of the anode support layer may not match that of the electrolyte layer, resulting in uneven thermal stress, which in turn causes cracks; in addition, if the thermal expansion coefficients of the sealing material and the support layer do not match, the anode support layer may also fracture; when the connector is connected to the support layer, if the connection method is unreasonable or the connection point is subjected to additional stress, the anode support layer may also fracture... The fracture site of the above-mentioned support will lead to the mixing of fuel and oxidant gas, and even cause serious explosion accidents.

[0004] Traditional ceramic material toughening technologies have certain defects in the toughening of the anode support of proton ceramic fuel cells and are difficult to be successfully applied. Specifically, (1) Fiber toughening technology is to increase the overall toughness of the anode by mixing high-toughness fibers such as YSZ, Al2O3, and ZrO2 in the anode support. However, because the cost of the fiber is relatively high and the fiber structure is difficult to maintain during the high-temperature sintering process of the anode support, and the fiber material often affects the catalytic activity of the anode, it is difficult to popularize. (2) Heat treatment toughening technology is to change the crystal state and grain structure of the material by heating to improve the toughness of the material. Because the anode support of proton ceramic fuel cells needs to be sintered at high temperature (1450℃), simple heat treatment is difficult to change the toughness of the material and is not suitable for the anode of proton ceramic fuel cells. (3) Microstructure optimization toughening technology is to increase the overall toughness of the anode support by changing the microstructure of the material, such as reducing the porosity and particle size. However, because the anode support needs to maintain a certain amount of micropores to transmit hydrogen fuel during the operation of the fuel cell, this method has certain limitations.

[0005] At present, the strength and fracture toughness of proton ceramic anode supports are often low, which restricts the preparation of large-scale proton ceramic fuel cells and the subsequent assembly and operation of the stack. Therefore, it is necessary to develop a new anode support with high fracture toughness and a preparation method to ensure the integrity of the entire battery structure and the reliability of the stack performance. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a high-toughness anode support and a preparation method and application thereof, aiming to solve the problem that the anode support has insufficient toughness and the existing anode support toughening technology is difficult to take effect.

[0007] The technical solution of the present invention is as follows:

[0008] A first aspect of the present invention provides a method for preparing a high-toughness anode support, comprising the steps of:

[0009] The nickel oxide, electrolyte powder, starch and rare earth aluminate are mixed and ball-milled to obtain anode powder;

[0010] The anode powder is pressed by dry pressing to obtain an anode support green sheet;

[0011] The anode support green sheet is calcined at high temperature to obtain the high-toughness anode support.

[0012] Optionally, the rare earth aluminate is selected from one of LaAlO3, NdAlO3, and GdAlO3.

[0013] Optionally, the amount of the rare earth aluminate used accounts for 0.5-2% of the sum of the mass of the nickel oxide, electrolyte powder and starch.

[0014] Preferably, the amount of the rare earth aluminate used accounts for 1% of the total mass of the nickel oxide, electrolyte powder and starch.

[0015] Optionally, the mass ratio of the nickel oxide, electrolyte powder and starch is (6-7):(3-4):1.

[0016] Preferably, the mass ratio of the nickel oxide, electrolyte powder and starch is 6:4:1.

[0017] Optionally, the electrolyte powder is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ or BaZr 0.44 Ce 0.36 Y 0.2 O 3-δ .

[0018] Optionally, the ball milling treatment conditions are: a rotation speed of 350-400 r / min and a ball milling time of 40-60 min. The ball milling treatment can prevent the starch from floating on the alcohol surface during the drying alcohol standing process and affecting the unevenness of the material.

[0019] Optionally, the pressing conditions are: pressure of 6 to 10 MPa, and pressing time of 40 to 60 s.

[0020] Preferably, the pressing conditions are: pressure of 8 MPa and pressing time of 40 s.

[0021] Optionally, the temperature of the high-temperature calcination is 1400-1500° C., and the time of the high-temperature calcination is 5-6 hours.

[0022] Preferably, the temperature of the high-temperature calcination is 1450°C, and the time of the high-temperature calcination is 5 hours.

[0023] The second aspect of the present invention provides a high-toughness anode support, which is prepared by the method for preparing a high-toughness anode support.

[0024] The third aspect of the present invention provides an application of the high-toughness anode support in a proton ceramic fuel cell.

[0025] Beneficial effects:

[0026] The present invention prepares the high-toughness anode support by adding rare earth aluminate to anode powder composed of nickel oxide, electrolyte powder and starch, and then ball milling, pressing and high-temperature calcination. The prepared high-toughness anode support significantly increases the mechanical strength and fracture toughness, thereby increasing the fracture toughness of the battery itself, and maintains the electrochemical properties and catalytic activity of the anode of the proton conductor fuel cell, ensuring the integrity of the entire battery structure and the reliability of the stack performance. At the same time, the technical method of preparing the high-toughness anode support of the present invention is suitable for industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a schematic flow chart of a method for preparing a high-toughness anode support.

[0028] Figure 2 The XRD test patterns of LaAlO3, BZCYYb and the mixture of the two in the embodiments of the present invention are shown in FIG.

[0029] Figure 3 EIS polarization curve test diagram of a single cell assembled with the anode prepared in Comparative Example 1 of the present invention

[0030] Figure 4 This is an IV curve test diagram of a single cell assembled with the anode prepared in Comparative Example 1 of the present invention.

[0031] Figure 5 This is an EIS polarization curve test diagram of a single cell assembled with the anode support prepared in Example 1 of the present invention.

[0032] Figure 6 This is an IV curve test diagram of a single cell assembled with the anode support prepared in Example 1 of the present invention.

[0033] Figure 7 This is an IV curve test diagram of a single cell assembled with the anode support prepared in Example 2 of the present invention.

[0034] Figure 8 This is an IV curve test diagram of a single cell assembled with the anode support prepared in Example 3 of the present invention.

[0035] Fig. 9 This is the fracture toughness test model of single-edge notched beam.

[0036] Fig.10 This is a comparison chart of the fracture toughness calculation results of the anode support body with different toughening materials added in the present invention. DETAILED DESCRIPTION

[0037] The present invention provides a high-toughness anode support and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0039] The embodiment of the present invention provides a method for preparing a high-toughness anode support, comprising the following steps:

[0040] S1, mixing nickel oxide, electrolyte powder, starch and rare earth aluminate, and performing ball milling to obtain anode powder;

[0041] S2, pressing the anode powder by dry pressing to obtain an anode support green sheet;

[0042] S3, calcining the anode support green sheet at high temperature to obtain the high-toughness anode support.

[0043] In step S1, in some embodiments, the rare earth aluminate is selected from one of LaAlO3, NdAlO3, and GdAlO3. The use of rare earth aluminates, especially LaAlO3, in the toughening of the anode support of a solid oxide fuel cell can significantly increase the fracture toughness of the anode support and maintain the electrochemical properties and catalytic activity of the anode support. After LaAlO3 is added to the anode powder containing nickel oxide, electrolyte powder, and starch, the lattice is reoriented under the action of external stress, accompanied by plastic deformation, resulting in energy consumption. LaAlO3 itself is a ferroelastic material with domain transformation toughening effect. Moreover, after LaAlO3 and the electrolyte BZCYYb are mixed and calcined at high temperature, new substances are generated, the particles are refined, and the refined grains often deflect the fracture path, thereby changing the fracture mode from transcrystalline to intercrystalline. Therefore, the embodiment of the present invention achieves the toughening effect of the anode support by adding LaAlO3 to the anode powder of nickel oxide, electrolyte powder, and starch.

[0044] In some embodiments, the amount of the rare earth aluminate used accounts for 0.5-2% of the total mass of the nickel oxide, electrolyte powder, and starch.

[0045] In a preferred embodiment, the amount of the rare earth aluminate is 1% of the sum of the mass of the nickel oxide, electrolyte powder and starch. When the mixing ratio of LaAlO3 is large, the power output of the battery is greatly attenuated; when the ratio is small, the improvement of fracture toughness is not obvious enough.

[0046] In some embodiments, the mass ratio of the nickel oxide, electrolyte powder and starch is (6-7):(3-4):1.

[0047] In a preferred embodiment, the mass ratio of the nickel oxide, electrolyte powder and starch is 6:4:1.

[0048] In some embodiments, the electrolyte powder is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ or BaZr 0.44 Ce 0.36 Y 0.2 O 3-δ .

[0049] In some embodiments, the ball milling treatment is performed under the conditions of: a rotation speed of 350 to 400 r / min and a ball milling time of 40 to 60 min.

[0050] In a preferred embodiment, the ball milling treatment is carried out under the conditions of: a rotation speed of 400 r / min and a ball milling time of 40 min. The ball milling treatment can prevent the starch from floating on the alcohol surface during the drying alcohol standing process and affecting the unevenness of the material.

[0051] In step S2, in some embodiments, the pressing conditions are: pressure of 6 to 10 MPa, and pressing time of 40 to 60 s.

[0052] In a preferred embodiment, the pressing conditions are: pressure of 8 MPa and pressing time of 40 s.

[0053] In step S3, in some embodiments, the temperature of the high temperature calcination is 1400-1500° C., and the time of the high temperature calcination is 5-6 hours.

[0054] In a preferred embodiment, the temperature of the high-temperature calcination is 1450°C, and the time of the high-temperature calcination is 5 hours.

[0055] The embodiment of the present invention provides a high-toughness anode support, which is prepared by using the method for preparing a high-toughness anode support.

[0056] The embodiment of the present invention also provides an application of the high-toughness anode support in a proton ceramic fuel cell.

[0057] The following describes it in detail through specific embodiments.

[0058] Example 1

[0059] First, the basic materials for the synthesis of the anode support include nickel oxide, electrolyte powder BZCYYb and starch, which are mixed in a mass ratio of 6:4:1, and 1% LaAlO3 (accounting for the mass sum of NiO+BZCYYb+starch) is added. Then, anhydrous alcohol is added and ground in a ball mill. The ball mill is milled at a speed of 400 rpm for 40 minutes, fully mixed and the alcohol is volatilized under mechanical grinding to obtain the anode support powder.

[0060] The anode support powder was pressed at a pressure of 8 MPa for 40 seconds to obtain an anode support green sheet.

[0061] The anode support green sheet was fired at 1450° C. for 5 hours to obtain a dense anode.

[0062] The schematic diagram of the above preparation process is as follows Figure 1 shown.

[0063] Example 2

[0064] The only difference from Example 1 is that 3% LaAlO3 is added (accounting for the total mass of NiO+BZCYYb+starch).

[0065] Example 3

[0066] The only difference from Example 1 is that 5% LaAlO3 (accounting for the total mass of NiO+BZCYYb+starch) is added.

[0067] Comparative Example 1

[0068] The only difference from Example 1 is that LaAlO3 is not added.

[0069] Characterization and testing

[0070] XRD characterization

[0071] XRD test data show that Figure 2 As shown, after LaAlO3 and electrolyte BZCYYb are mixed, new substances will be generated, and the subsequent effect description shows that the generation of this new substance is beneficial to the improvement of anode toughness.

[0072] (1) Electrochemical test

[0073] Preparation of single cell: Use powder anode, spin-coat electrolyte and high-temperature co-sintering to prepare anode-supported half-cell. The control group and experimental group were prepared with anode powders of different compositions:

[0074] Control group: BZCYYb containing 1% nickel oxide was used as the electrolyte, and the anode was a mixed powder of NiO:BZCYYb:starch = 6:4:1, namely, composed of 6g NiO, 4g BZCYYb and 1g starch.

[0075] Experimental group: BZCYYb containing 1% nickel oxide was used as the electrolyte, and the anode powder consisted of 6g NiO, 4g BZCYYb, 1g starch and 0.11g LaAlO3 (accounting for 1% of the total mass of NiO, BZCYYb and starch).

[0076] The role of NiO is mainly to generate Ni element as a catalyst for hydrogen oxidation reaction, while starch is mainly used to create pores in the anode.

[0077] An appropriate amount of ethanol was added to the anode powder and ground at a speed of 400 rpm for 40 minutes by high-energy ball milling. The alcohol was evaporated by manual grinding and drying to obtain the anode powder. The control group pressed 0.35g of anode powder into a disc under a tablet press at a pressure of 4MPa. The experimental group first pressed 0.2g of anode powder containing 1% LaAlO3 into a disc under a tablet press at a pressure of 4MPa as an anode, and then evenly spread 0.15g of anode powder on its surface and pressed it into a disc under a tablet press at a pressure of 4MPa as a functional layer. BZCYYb electrolyte solution was evenly spin-coated on the surface of the anode, 10 drops each time, and dried at 70°C after spin coating, repeated 3 times to obtain a half-cell green body. Then, it was calcined at 1450°C in a muffle furnace under an air atmosphere for 5 hours to obtain a half-cell. The cathode slurry was sprayed on the surface of the electrolyte and calcined at 1000°C for 2 hours to fully combine the cathode and the electrolyte to obtain a complete single cell. Silver paste and silver wire are used for current collection on both sides of the cathode and anode.

[0078] The electrochemical tests were performed using a Keithley 2460 digital source meter and a Princeton electrochemical workstation, including EIS impedance and IV curve tests.

[0079] The EIS polarization curve and IV curve of the control group anode obtained by the test are as follows: Figure 3 and Figure 4 As shown, the EIS polarization curve and IV curve of the high toughness anode support in the experimental group are as follows Figure 5 and Figure 6 The test results show that the battery power density under the original anode is 660mW cm at a temperature of 650℃. -2 The power density of the cell assembled with 1% LaAlO3 anode support is 603 mW cm -2, which only decreased by 8.6%. At the same time, by observing the impedance spectrum, it was found that the impedance above 500°C hardly increased, which indicates that at the operating temperature (650°C), adding LaAlO3 to the anode support hardly increased the battery impedance.

[0080] The influence of different LaAlO3 anode supports on the performance of the single cell was further tested. The power density of LaAlO3 anode supports with contents of 3% and 5% (the percentage of LaAlO3 in the total mass of NiO, BZCYYb and starch) was tested. The test results are shown as follows: Figure 7 and Figure 8 As shown in Figure 2, the battery power density at 650°C is 115 mW cm -2 and 102mWcm -2 , showing a greater degree of attenuation compared to the original battery.

[0081] (2) Fracture toughness test

[0082] A single-edge notched beam is a common experimental sample used to measure materials. In this experiment, the sample is cut into a beam with a specific geometry, one side of which is machined into a single-edge notch. This notch is a defect introduced into the sample, simulating a possible crack in the material. Then, an external load is applied to induce crack growth around the notch, such as Fig. 9 By measuring the loading and crack growth behavior, the fracture toughness parameters of the material can be calculated, such as the fracture toughness K IC The fracture toughness test method and calculation formula used are based on the national standard "Fine Ceramics Fracture Toughness Test Method Single Edge Precracked Beam (SEPB) Method" (GB / T23806-2009).

[0083] The calculation results are as follows Fig.10 As shown in the figure, the improvement of anode toughness by various toughening materials is compared. The results show that rare earth aluminates (LaAlO3, NdAlO3, GdAlO3) all have obvious toughening effects on anode supports, among which LaAlO3 has the best toughening effect on anode supports. This is because LaAlO3 itself is a ferroelastic material with domain transformation toughening effect. Moreover, after LaAlO3 and electrolyte BZCYYb are mixed, new substances are generated and particles are refined. Refined grains often deflect the fracture path, changing the fracture mode from transgranular to intergranular. The fracture toughness K of the anode support prepared when the content of LaAlO3 accounts for 1% of the total mass of NiO, BZCYYb and starch is 1c From 2.29MPa m 1 / 2 Increased to 2.97MPa m 1 / 2, the fracture toughness increased by 29.7%. This ratio of LaAlO3 achieves a good balance between increased toughness and electrochemical performance.

[0084] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a high-toughness anode support, It is characterized in that Includes steps: The nickel oxide, electrolyte powder, starch and rare earth aluminate are mixed and ball-milled to obtain anode powder; The anode powder is pressed by dry pressing to obtain an anode support green sheet; The anode support green sheet is calcined at high temperature to obtain the high-toughness anode support.

2. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The rare earth aluminate is selected from LaAlO 3 、NdAlO 3 、GdAlO 3 One of them.

3. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The amount of the rare earth aluminate used accounts for 0.5-2% of the total mass of the nickel oxide, electrolyte powder and starch.

4. The method for preparing a high-toughness anode support according to claim 3, It is characterized in that The amount of the rare earth aluminate used accounts for 1% of the total mass of the nickel oxide, electrolyte powder and starch.

5. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The mass ratio of the nickel oxide, electrolyte powder and starch is (6-7):(3-4):

1.

6. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The electrolyte powder is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ or BaZr 0.44 Ce 0.36 Y 0.2 O 3-δ .

7. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The ball milling conditions are: a rotation speed of 350 to 400 r / min and a ball milling time of 40 to 60 min; And / or, the pressing conditions are: pressure of 6-10 MPa, and pressing time of 40-60 s.

8. The method for preparing a high-toughness anode support according to claim 1, It is characterized in that The temperature of the high-temperature calcination is 1400-1500° C., and the time of the high-temperature calcination is 5-6 hours.

9. A high-toughness anode support, It is characterized in that The high-toughness anode support is prepared by the method for preparing the high-toughness anode support according to any one of claims 1 to 8.

10. Use of the high-toughness anode support according to claim 9 in a proton ceramic fuel cell.

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