Assembled fuel cell with double electrolyte structure and method for manufacturing the same

Abstract

The application provides an assembled fuel cell with a double-layer electrolyte structure and a preparation method thereof, and the fuel cell is prepared by the following steps: a semi-cell blank is obtained by molding lanthanum-praseodymium co-doped cerium oxide; an electrolyte solution of strontium-doped lanthanum ferrite is brushed on an electrolyte end of the semi-cell blank to obtain a semi-cell blank with a double-layer structure; a cell blank is obtained by assembling the semi-cell blank with a double-layer structure and a cathode blank in a clamp; and the cell blank is sintered at 400-500 DEG C to obtain the fuel cell. In the anode material of the fuel cell, NCAL is reduced to metallic nickel under a reducing atmosphere, which plays a role in conducting electrons and catalyzing reduction of fuel, and the components are mutually synergistic, have high electrocatalytic activity and electron conductivity at a three-phase interface, and have good chemical and thermal compatibility with electrolyte materials and connecting body materials. The material cost is low, the preparation process is simple, the noble metal material can be replaced, and the product cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, specifically to an assembled fuel cell with a double-layer electrolyte structure and its preparation method. Background Technology

[0002] With the rapid advancement of society, people's consumption of energy resources is increasing daily. Currently, fossil fuels (coal, oil, and natural gas) remain the primary energy resources worldwide. However, the technology for utilizing fossil fuels is still not perfect, and coupled with the finite and non-renewable nature of fossil fuels, this has led to energy shortages and environmental pollution problems. To address these issues, in recent years, researchers worldwide have been developing new and renewable energy sources while also seeking to change traditional energy conversion methods, improve their actual utilization efficiency, and reduce the environmental impact of fossil fuel use.

[0003] In the field of new energy, fuel cells occupy an important position and are considered one of the most promising products to replace traditional fossil fuel power generation. They can directly convert chemical energy into electrical energy without combustion, and the conversion process overcomes the limitations of the Carnot cycle. Fuel cells typically consist of three components: electrolyte, cathode, and anode. The choice of electrolyte material determines the type of fuel cell, operating temperature, and energy conversion efficiency. Among existing fuel cells, solid oxide fuel cells (SOFCs) with solid oxide electrolytes have attracted much attention due to their unique advantages and characteristics. Low-temperature SOFCs are a future development trend; lower operating temperatures can reduce costs and extend service life. Therefore, the development of low-temperature SOFCs is an urgent need for the commercialization of their power generation systems. However, as the operating temperature decreases, the ionic conductivity of the SOFC electrolyte material and the catalytic activity of the corresponding electrodes also decrease, leading to a sharp decline in performance. To ensure that SOFCs maintain high output power at relatively low operating temperatures, current solutions include thin-film electrolyte layers and the development of electrolytes with high ionic conductivity and electrode materials with high catalytic activity at low temperatures. With further research into LTSOFCs, scientists have achieved significant results regarding cerium oxide-based electrolytes. Cerium oxide is considered the most suitable ion conductor material for low-temperature operation in SOFCs. This patent, based on cerium oxide materials, uses lanthanum-praseodymium co-doped cerium oxide as the main material to investigate its practical application prospects in SOFCs. Compared to other electrolyte materials, lanthanum-praseodymium co-doped cerium oxide has advantages such as easy availability and low cost, demonstrating great potential for the commercialization of fuel cells.

[0004] After developing the above-mentioned electrolyte materials, it is also necessary to consider the chemical compatibility and thermal expansion coefficient matching between the various component materials in order to truly apply them to fuel cells, so as to avoid phenomena such as battery thermal cracking and severe degradation of electrochemical performance due to mutual reaction and inconsistent thermal expansion. Summary of the Invention

[0005] The purpose of this invention is to provide an electrolyte material that still has high ionic conductivity at medium and low temperatures.

[0006] The purpose of this invention is to provide a method for preparing a double-layer structure with an electrolyte layer.

[0007] Another objective of this invention is to provide a method for preparing the aforementioned electrolyte material.

[0008] Another objective of this invention is to propose a novel fuel cell containing the aforementioned bilayer electrolyte material.

[0009] Another objective of this invention is to provide a method for preparing the aforementioned fuel cell.

[0010] The present invention first provides the following technical solution:

[0011] An electrolyte material includes an LCP (Liquid Crystal Polymer) having ionic conductivity. A method for preparing the electrolyte material includes the following steps:

[0012] (1) The weighed rare earth carbonate was calcined at high temperature to obtain a red powder;

[0013] (2) The obtained red powder is ground to obtain LCP with ionic conductor.

[0014] The calcination temperature is 600–1000℃, preferably 700–800℃. The calcination time is 1–10 hours, preferably 4–5 hours.

[0015] The grinding rate is 1–5 r / s. The grinding time is 10–60 min.

[0016] An electrolyte solution comprises strontium-doped lanthanum ferrite (LSCF) and anhydrous ethanol; the mass ratio of LSCF to anhydrous ethanol is 1:1 to 10, preferably 1:1.5 to 3. The electrolyte solution is obtained by mixing the LSCF and anhydrous ethanol and then grinding them at a grinding rate of 5 to 10 r / s for 1 to 5 min.

[0017] The strontium-doped lanthanum ferrite (LSCF) described in the above scheme is a perovskite-type material that is a stable cubic and tetragonal crystal at room temperature.

[0018] The present invention provides a double-layer electrolyte structure, comprising the electrolyte material described above, and the electrolyte solution described above.

[0019] An assembled fuel cell with a double-layer electrolyte structure includes the double-layer electrolyte structure described above.

[0020] The anode material of the fuel cell contains Ni and NCAL. Preferably, the Ni is foamed metal Ni.

[0021] The cathode material of the fuel cell contains Ni and NCAL. Preferably, the Ni is foamed metal Ni.

[0022] The method for preparing an assembled fuel cell with a double-layer electrolyte structure includes the following steps:

[0023] The anode material and cathode material are respectively fabricated into an anode layer and a cathode layer;

[0024] The anode layer and the LCP of the ion conductor are molded together to obtain a half-cell blank;

[0025] The electrolyte solution is brushed onto the electrolyte end of the half-cell blank to obtain a double-layer half-cell blank.

[0026] The cathode layer is molded to obtain a cathode blank;

[0027] A battery blank is obtained by assembling a half-cell blank containing a double-layer structure and a cathode blank in a fixture;

[0028] The battery blank is sintered at 400-500°C to obtain the fuel cell.

[0029] The present invention has the following beneficial effects:

[0030] The electrolyte material of this invention has a stable structure, excellent mechanical and electrical properties, and low price. The preparation method of the electrolyte material is simple, and high ionic conductivity can be obtained at a relatively low temperature (400-600℃). The resulting battery can achieve good performance output in the medium and low temperature range.

[0031] The fuel cell of the present invention can maintain good electrical performance at medium and low temperatures. The various parts of the battery are tightly combined and their thermal expansion coefficients are matched with each other. In practical operation, problems such as interface cracking caused by changes in internal material stress will not occur.

[0032] In the anode material of the fuel cell of this invention, NCAL is reduced to metallic nickel under a reducing atmosphere. In addition to playing the role of conducting electrons and catalytically reducing fuel, the components work together to have high electrocatalytic activity and electronic conductivity at the three-phase interface. At the same time, it has good chemical and thermal compatibility with electrolyte materials and connector materials. The material cost is low and the preparation process is simple. It can be used to replace precious metal materials and reduce product costs.

[0033] The fuel cell of this invention exhibits good power output when tested at a temperature of 450°C, and can successfully reduce the operating temperature of SOFC to below 500°C, which makes it possible for the further commercialization of solid oxide fuel cells. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the battery structure of the assembled fuel cell described in Example 6.

[0035] Figure 2 This is a comparison chart of the electrical performance tests of assembled fuel cells with different numbers of LSCF layers in Example 7.

[0036] Figure 3 The graph shows the electrical performance test results of the fuel cell in Example 8 at different temperatures.

[0037] Figure 4 This is a SEM cross-sectional view of the assembled fuel cell described in Example 8. Detailed Implementation

[0038] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0039] Example 1

[0040] The ion conductor LCP is prepared by the following process:

[0041] (1) Weigh a certain mass of rare earth carbonate and calcine it at a high temperature of 800℃ for 4 hours to obtain a red powder.

[0042] (2) Grind the calcined red powder evenly to obtain the desired electrolyte LCP.

[0043] Example 2

[0044] LSCF solution is prepared by the following process:

[0045] (1) Mix LSCF and anhydrous ethanol at a mass ratio;

[0046] (2) Grind the mixed solution evenly to dissolve it completely and obtain the required LSCF solution.

[0047] Example 3

[0048] The anode is prepared through the following process:

[0049] Ni0.8Co0.15Al0.05LiOδ (NCAL) powder was added to 1 mL of terpineol and stirred for 10 min to ensure thorough and uniform mixing, thus obtaining an NCAL slurry. The prepared slurry was then coated onto a 2 mm thick nickel foam and dried in a drying oven at 120 °C for 15 min to complete the preparation of the Ni-NCAL electrode.

[0050] Example 4

[0051] The half-cell structure was prepared using the following process:

[0052] Weigh 0.3g of the ionic conductor LCP obtained in Example 1, and place the Ni-NCAL electrode and LCP obtained in Example 3 into a mold sequentially. Apply a load of 200-300MPa using a hydraulic press to uniaxially press it into a disc with a diameter of 13mm, thus obtaining the Ni-NCAL-LCP structure. Then, using the LSCF solution obtained in Example 2, brush the LSCF solution onto the LCP side of the Ni-NCAL-LCP using a brush coating method, and then dry it in a drying oven at 120°C for 5 minutes. Repeat the brush coating and drying process until the optimal thickness is achieved to obtain the Ni-NCAL-LCP-LSCF half-cell structure.

[0053] Example 5

[0054] The cathode is prepared through the following process:

[0055] Ni0.8Co0.15Al0.05LiOδ (NCAL) powder was added to 1 mL of terpineol and stirred for 10 min to ensure thorough and uniform mixing, resulting in an NCAL slurry. This slurry was then coated onto a 2 mm thick layer of nickel foam and dried in a drying oven at 120 °C for 15 min to complete the preparation of the Ni-NCAL electrode. The Ni-NCAL electrode was then placed separately in a mold and uniaxially pressed into a 13 mm diameter disc using a hydraulic press under a load of 200–300 MPa, thus obtaining the cathode layer required for battery assembly.

[0056] Example 6

[0057] Solid oxide fuel cells are prepared using the following process:

[0058] The half-cell obtained in Example 4 and the cathode layer obtained in Example 5 were sequentially placed into a fixture and pressed tightly. The mixture was then sintered at 450°C for 30 minutes to obtain the assembled solid oxide fuel cell.

[0059] Example 7

[0060] Battery performance test:

[0061] The assembled solid oxide fuel cell obtained in Example 5 was tested at 450°C with H2 introduced into the anode side and air introduced into the cathode side of the half-cell. Figure 1 As shown, the hydrogen flow rate was controlled at 120 mL / min for battery performance testing, and the open-circuit voltage and power of the battery were recorded. The results are as follows. Figure 2 As shown in the figure, the assembled fuel cell of this structure exhibits high power output at 450℃. Furthermore, the cell performance initially increases and then decreases with increasing LSCF layer number. The cell output performance reaches its optimal level when the LSCF brush layer number is two, with a maximum power output of 562 mW / cm². 2 .

[0062] The cross-sectional microstructure of the sintered battery was observed using SEM, such as... Figure 4 As shown, the interfaces between the electrode materials and the electrolyte materials are tightly bonded without cracks or gaps, indicating that their thermal expansion is well matched, and they have good chemical and thermal compatibility, as well as good chemical and mechanical stability.

[0063] Example 8

[0064] The assembled fuel cell with two layers of LSCF coated in Example 7 was subjected to battery performance tests at different test temperatures, following the method described in Example 7. The tests revealed that it still exhibited high output performance below 450°C, such as at temperatures between 420 and 440°C. Figure 3 The performance test graph of the battery shown at 440℃ indicates that the battery's maximum output power reached 218mW / cm². 2 .

[0065] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A double layer electrolyte structure, characterized by, The electrolyte material further comprises an electrolyte solution; The electrolyte material comprises LCP with ion conductor; The preparation method of the electrolyte material comprises the following steps: (1) The weighed rare earth carbonate is calcined at high temperature to obtain red powder; the calcination temperature is 600-1000℃, and the calcination time is 1-10h; (2) The obtained red powder is ground to obtain LCP with ion conductor; The electrolyte solution comprises strontium-doped lanthanum ferrite LSCF and anhydrous ethanol; The mass ratio of LSCF to anhydrous ethanol is 1:1-10; The LSCF and anhydrous ethanol are mixed and ground to obtain the electrolyte solution, and the grinding rate is 5-10r / s.

2. An assembled fuel cell of a double-layer electrolyte structure, characterized by The double-layer electrolyte structure of claim 1 is included.

3. An assembled fuel cell of a double-layer electrolyte structure according to claim 2, characterized by: The anode material of the fuel cell contains Ni and NCAL.

4. An assembled fuel cell of a double-layer electrolyte structure according to claim 2, characterized by: The cathode material of the fuel cell contains Ni and NCAL.

5. A method of fabricating a fuel cell of a bi-layer electrolyte structure according to any one of claims 3 to 4, characterized in that, The method comprises the following steps: The anode material and the cathode material are respectively prepared into an anode layer and a cathode layer; The anode layer is molded with the LCP with ion conductor to obtain a half-cell blank; The electrolyte solution is brushed on the electrolyte end of the half-cell blank to obtain a half-cell blank with double-layer structure; The cathode layer is molded to obtain a cathode blank; The half-cell blank with double-layer structure and the cathode blank are assembled in a clamp to obtain a cell blank; The cell blank is sintered at 400-500℃ to obtain the fuel cell.

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