PCFC with porous skeleton infiltration type self-assembly cathode and preparation method thereof

Abstract

The invention relates to a PCFC with a porous skeleton infiltration type self-assembly cathode and a preparation method thereof. The preparation method comprises the following steps: preparing skeleton slurry by using a pore forming agent; impregnating the skeleton slurry on the electrolyte surface of a PCFC substrate, drying, and co-sintering to obtain a half cell; the pore-forming agent comprises PMMA (polymethyl methacrylate) microspheres and soluble starch; the particle size of the PMMA microspheres is 1-10 [mu] m, and the particle size of the soluble starch is 50-200 nm; dissolving the cathode powder or the cathode powder and an active component precursor in ethanol, uniformly mixing, and drying to obtain mixed powder; preparing an infiltration solution from the mixed powder and ethylene glycol; and sealing the two ends of the half-cell, immersing the half-cell in the infiltration liquid, drying and sintering until the preset loading capacity is reached. According to the invention, the problems of few oxygen supply and moisture removal paths caused by insufficient porosity of the cathode of the traditional fuel cell and electrode falling caused by thermal stress between the cathode and electrolyte are solved, and the electrochemical performance and stability at medium and low temperatures are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to a PCFC with a porous framework infiltrated self-assembled cathode and a preparation method thereof. Background Art

[0002] PCFC (Protonic Ceramic Fuel Cell) is a fuel cell with a proton conductor (such as perovskite-type oxide) as the electrolyte. Its working principle is to generate electric energy by the transfer of protons (i.e., hydrogen ions) in the electrolyte. Different from the traditional solid oxide fuel cell (SOFC) that must operate in a high-temperature environment of 800 - 1000 °C, PCFC can operate in a lower temperature range because protons have a higher mobility in the temperature range of 300 - 700 °C.

[0003] The traditional PCFC cathode structure has problems such as low porosity or uneven pore distribution, large oxygen transport resistance, lack of a water removal path, and cation segregation generating impurity phases that hinder charge-mass transfer. The cathode-electrolyte is prone to thermal expansion mismatch, resulting in interfacial stress during the thermal cycling of the battery, contact defects between layers, leading to high interfacial impedance and a reduction in reactive sites. Water is generated on the cathode side, and the high concentration of water vapor is likely to cause the surface separation of cations from the perovskite lattice, resulting in impurities that impede charge-mass transfer, and the reaction kinetics of the oxidation-reduction reaction (ORR) is slow at medium and low temperatures. In addition, due to the mismatch of thermal expansion coefficients or insufficient mechanical strength, cracks or peeling occur during the thermal cycling process, affecting the long-term stability of the battery.

[0004] In the prior art, on the one hand, the battery performance is improved by the development of new perovskite-based materials. However, the development of new materials requires complex synthesis processes and long-term performance verification, and may face the trade-off between mechanical properties and electrochemical properties. On the other hand, the performance is improved by structural optimization based on existing materials. For example, a transition layer with a moderate thermal expansion coefficient is introduced between the cathode layer and the barrier layer, and a composite cathode layer with a thermal expansion coefficient matching that of the transition layer is prepared. However, the multi-phase composite cathode material requires precise control of the proportion and distribution of each component, and the mixing of multiple different components may have problems of uneven conductivity, affecting the overall battery performance.

[0005] Therefore, there is currently a lack of an effective solution to improve the stability of PCFC at low temperatures. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a PCFC with a porous framework infiltrating self-assembled cathode and its preparation method, which solves the problems of insufficient oxygen supply and few moisture removal paths caused by insufficient cathode porosity in traditional fuel cells, electrode shedding caused by thermal stress between the cathode and the electrolyte, and the generation of impurities due to cation segregation in the cathode, which affects the charge-mass transfer, improves the electrochemical performance of the PCFC at medium and low temperatures, and enhances the stability of the battery.

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

[0008] The present invention provides a preparation method of a PCFC with a porous framework infiltrating self-assembled cathode, including:

[0009] Obtaining a PCFC substrate with an electrolyte loaded on an anode support;

[0010] Preparing a porous framework, which includes: mixing a pore-forming agent, a proton-conducting electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol and ball-milling them to prepare a framework slurry; impregnating the framework slurry on the surface of the electrolyte of the PCFC substrate, and co-sintering after drying to obtain a half-cell with a framework structure;

[0011] The pore-forming agent includes PMMA microspheres and soluble starch;

[0012] The particle size of the PMMA microspheres is 1 - 10 μm, and the particle size of the soluble starch is 50 - 200 nm;

[0013] Preparing a cathode infiltration liquid, which includes: dissolving a cathode powder or the cathode powder and an active component precursor in ethanol, mixing evenly and drying to obtain a mixed powder; mixing the mixed powder with ethylene glycol in a certain proportion and ball-milling to prepare an infiltration liquid;

[0014] Sealing both ends of the half-cell, then immersing it in the infiltration liquid for ultrasonic-assisted infiltration, drying and sintering; repeating the infiltration and sintering for multiple times until a preset loading amount is reached to obtain the PCFC.

[0015] The further technical solution is:

[0016] The mass ratio of the PMMA microspheres to the soluble starch is 3:1 - 1:1.

[0017] The mass ratio of the pore-forming agent, the proton-conducting electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol is (5 - 45):(5 - 45):2:1:3:100.

[0018] The active component precursor is one or more of transition metals, transition metal oxides, rare earth metals, and rare earth metal oxides.

[0019] The framework slurry is impregnated on the surface of the tubular PCFC electrolyte. When co-sintered after drying, the sintering temperature is 1200 - 1450 °C, the heating rate is 1 - 5 °C / min, and the holding time is 4 - 10 h.

[0020] During the ultrasonic-assisted infiltration process, the ultrasonic frequency is 40 - 60 kHz, and the ultrasonic treatment time is 10 - 30 minutes.

[0021] The proton conductor electrolyte powder is BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The cathode powder is PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ .

[0022] The mass ratio of the mixed powder to ethylene glycol is 1:(2 - 5);

[0023] The mass of the active component precursor is 1% - 10% of the mass of the cathode powder.

[0024] It is immersed in the infiltration liquid for ultrasonic-assisted infiltration. When sintered after drying, the sintering temperature is 900 - 1000 °C, the heating rate is 1 - 5 °C / min, and the holding time is 2 - 5 h.

[0025] The present invention also provides a PCFC with a porous framework infiltrated self-assembled cathode prepared according to the above preparation method.

[0026] The beneficial effects of the present invention are as follows:

[0027] The PCFC of the embodiment of the present invention has a porous framework infiltrated self-assembled cathode, which has high porosity, high pore distribution uniformity, and electrochemically reactive sites with relatively high activity. It provides an effective moisture removal path, inhibits the formation of impurity phases, promotes charge-mass transfer, enhances mechanical properties, improves interfacial contact, and improves long-term stability. Specifically, it has the following advantages:

[0028] Compared with the traditional cathode structure with low and uneven porosity, insufficient oxygen supply and moisture removal paths, and poor interfacial contact, the cathode infiltration framework of the present invention uses a two-component pore former to regulate and improve the porosity, improves the oxygen transport efficiency, reduces the gas diffusion resistance, expands the reactive area, and provides a larger electrochemically reactive surface area.

[0029] The skeletal porous structure provides an effective moisture removal path. The self-assembled cathode combined with the addition of active components further inhibits the segregation of cations in the cathode material, reduces the generation of impurity phases, ensures the smoothness of the charge-mass transfer process, maintains the chemical stability of the cathode material, and extends the service life of the battery.

[0030] The porous skeleton has a three-dimensional interpenetrating network structure, which can increase the loading capacity of the cathode, improve the interfacial contact between the cathode and the electrolyte, reduce the interfacial impedance, and effectively inhibit the generation of interfacial peeling or cracks, ensuring the stability of the battery during long-term operation.

[0031] Compared with the traditional composite cathode material, the preparation method of the porous skeleton infiltrated self-assembled cathode of the present invention is simple and low-cost. The ultrasonic field-assisted infiltration improves the uniformity of the distribution of the infiltration liquid by 60%. Compared with the traditional impregnation method, the active site density increases by 80%, and the interfacial contact area increases by 70%, ensuring the continuity of cathode conduction.

[0032] Other features and advantages of the present invention will be described in the subsequent specification or understood by implementing the present invention. Brief Description of the Drawings

[0033] Figure 1 It is a schematic structural diagram of a single PCFC prepared in an embodiment of the present invention.

[0034] Figure 2 It is a cross-sectional SEM image of the porous skeleton infiltrated cathode of a single PCFC prepared in Examples 5-7 of the present invention.

[0035] Figure 3 It is a j-U and j-P curve graph of a single PCFC prepared in Example 6 of the present invention.

[0036] In the figure: 1. Anode support; 2. Electrolyte; 3. Porous skeleton infiltrating the cathode; 4. Cathode surface layer. Detailed Description of the Invention

[0037] The following describes the specific embodiments of the present invention with reference to the drawings.

[0038] The embodiment of the present invention provides a preparation method of a PCFC with a porous skeleton infiltrated self-assembled cathode, including:

[0039] S0. Obtain a PCFC substrate with an electrolyte loaded on an anode support.

[0040] The anode support can be prepared by a phase inversion assisted extrusion method, and the electrolyte can be attached to the anode support by a dip coating method. The preparation method of the PCFC substrate belongs to the prior art and will not be elaborated in this embodiment.

[0041] S1. Prepare a porous skeleton, which includes: mixing a pore former, a proton conductor electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol and ball-milling them to prepare a skeleton slurry; impregnating the skeleton slurry on the surface of a tubular PCFC electrolyte, and co-sintering after drying to obtain a half-cell with a skeleton structure;

[0042] The pore former includes PMMA microspheres and soluble starch;

[0043] The particle size of the PMMA microspheres is 1-10 μm, and the particle size of the soluble starch is 50-200 nm;

[0044] S2. Prepare a cathode infiltration liquid, which includes: dissolving a cathode powder or the cathode powder and an active component precursor in ethanol, mixing them evenly and then drying to obtain a mixed powder; mixing the mixed powder and ethylene glycol in a certain proportion and ball-milling them to prepare an infiltration liquid;

[0045] S3. Seal both ends of the half-cell, only exposing the skeleton area; then immerse it in the infiltration liquid for ultrasonic-assisted infiltration, dry and sinter; repeat infiltration and sintering multiple times until a preset loading amount is reached to obtain the PCFC.

[0046] See Figure 1 , the structure of the PCFC prepared in the embodiment of the present invention includes an anode support 1, an electrolyte 2 is loaded on the anode support 1, and a porous skeleton is arranged on the electrolyte 2 by the impregnation method. The porous skeleton is soaked with the cathode infiltration liquid, that is, a porous skeleton 3 with an infiltrated cathode is formed, and the cathode infiltration liquid will form a cathode surface layer 4 on the surface of the porous skeleton 3 with an infiltrated cathode, thereby obtaining a complete PCFC.

[0047] Among them, the anode support 1 is preferably a multi-channel tubular structure.

[0048] In the embodiment of the present invention, a unique macro-mesoporous dual-mode pore structure is constructed through a two-component pore former system of PMMA microspheres + soluble starch, which helps to increase the porosity (up to 45-55%), and the pore distribution is uniform. Among them, the macro-pores can reach 3-8 μm, serving as a fast gas transmission channel, which can increase the oxygen diffusion coefficient by 3-5 times. The mesopores can reach 0.1-2 μm, which can greatly increase the three-phase interface density, which is 2-3 times that of the traditional cathode. The synergistic effect of the dual pores can increase the limiting current density at low temperature by 70% and reduce the polarization impedance by 68%.

[0049] The porous skeleton structure prepared in this embodiment provides an effective moisture removal path. Combined with the active components added in the cathode infiltration liquid, it inhibits the generation of impurity phases, promotes charge-mass transfer, maintains the chemical stability of the cathode material, and extends the service life of the battery.

[0050] To improve and enhance the battery performance, the optimization design can be carried out from the following aspects: the particle size setting and ratio of soluble starch and PMMA microspheres; the ratio of electrolyte powder and pore-forming agent; the concentration of the skeleton slurry; the dip coating thickness of the skeleton slurry; the concentration of the cathode infiltration liquid; the ultrasonic frequency and time; the infiltration and sintering times of the cathode infiltration liquid.

[0051] Among them, the mass ratio of the PMMA microspheres to the soluble starch is preferably 3:1 to 1:1.

[0052] Among them, the mass ratio of the pore-forming agent, proton conductor electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol is preferably (5-45):(5-45):2:1:3:100.

[0053] Among them, the proton conductor electrolyte powder preferably adopts BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ That is, BZCYYb; the cathode powder adopts PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ That is, PBSCF.

[0054] Among them, the active component precursor is preferably one or more of transition metals, transition metal oxides, rare earth metals, and rare earth metal oxides.

[0055] Among them, the mass ratio of the mixed powder to ethylene glycol is preferably 1:(2-5);

[0056] Among them, the mass of the active component precursor is preferably 1% to 10% of the mass of the cathode powder.

[0057] Among them, the preset loading amount is preferably 0.5% to 10% of the mass of the half-cell of the skeleton structure.

[0058] Among them, it is preferred to seal both ends of the half-cell with polytetrafluoroethylene green tape.

[0059] Among them, the impregnation times of the skeleton slurry are preferably 1 to 10 times.

[0060] Among them, the infiltration and sintering times of the cathode infiltration liquid are preferably 1 to 10 times.

[0061] The following further illustrates the preparation method of the PCFC with a porous skeleton infiltrated self-assembled cathode of the present application through specific examples.

[0062] Example 1:

[0063] A preparation method of a PCFC with a porous-skeleton infiltration self-assembled cathode. First, a PCFC substrate with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0064] (1) Preparation of the porous skeleton: Mix 4.2 g of PMMA microspheres, 0.8 g of soluble starch, 45 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a skeleton slurry; Immerse the skeleton slurry once on the electrolyte surface of the PCFC substrate, dry and then sinter. The sintering temperature is 1450 °C, the heating rate is 3 °C / min, and the holding time is 5 h;

[0065] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF and 8 g of ethylene glycol by ball milling;

[0066] (3) Seal both ends of the half-cell with polytetrafluoroethylene green tape, only exposing the skeleton area; Then immerse it in the infiltration liquid, carry out ultrasonic-assisted infiltration, the frequency is 40 kHz, the treatment time in the ultrasonic field is 10 minutes, dry and then sinter once. The sintering temperature is 1000 °C, the heating rate is 2 °C / min, and the holding time is 5 h.

[0067] Perform performance tests on the PCFC prepared in this example. Its peak power density at 450 °C is 0.13 W·cm -2 .

[0068] Example 2:

[0069] A preparation method of a PCFC with a porous-skeleton infiltration self-assembled cathode. First, a PCFC substrate with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0070] (1) Preparation of the porous skeleton: Mix 12.5 g of PMMA microspheres, 2.5 g of soluble starch, 35 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a skeleton slurry; Immerse the skeleton slurry once on the electrolyte surface of the PCFC substrate, dry and then sinter. The sintering temperature is 1450 °C, the heating rate is 4 °C / min, and the holding time is 5 h;

[0071] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF and 8 g of ethylene glycol by ball milling;

[0072] (3) Seal both ends of the half-cell with PTFE thread sealant, exposing only the framework area; then immerse it in the infiltration liquid and perform ultrasonic-assisted infiltration at a frequency of 40 kHz for 10 minutes in the ultrasonic field. After drying, sinter it once at a sintering temperature of 950 °C, a heating rate of 2 °C / min, and a holding time of 2 h.

[0073] Perform performance testing on the PCFC prepared in this example. Its peak power density at 450 °C is 0.17 W·cm -2 . Compared with Example 1, due to adjusting the component ratio of the pore-forming agent and increasing the addition amount, the framework pores in this example increase, and the cathode penetration amount increases, so the performance is improved.

[0074] Example 3:

[0075] A preparation method of a PCFC with a porous framework infiltrated self-assembled cathode. First, obtain a PCFC substrate with an electrolyte loaded on an anode support, and then perform the following steps:

[0076] (1) Preparation of the porous framework: Mix 21 g of PMMA microspheres, 4 g of soluble starch, 25 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a framework slurry; impregnate the framework slurry once on the electrolyte surface of the PCFC substrate, dry it, and then sinter it at a sintering temperature of 1450 °C, a heating rate of 3 °C / min, and a holding time of 5 h;

[0077] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF with 8 g of ethylene glycol and then ball mill them;

[0078] (3) Seal both ends of the half-cell with PTFE thread sealant, exposing only the framework area; then immerse it in the infiltration liquid and perform ultrasonic-assisted infiltration at a frequency of 40 kHz for 10 minutes in the ultrasonic field. After drying, sinter it once at a sintering temperature of 1000 °C, a heating rate of 2 °C / min, and a holding time of 4 h.

[0079] Perform performance testing on the PCFC prepared in this example. Its peak power density at 450 °C is 0.20 W·cm -2 . Compared with Example 2, due to further adjusting the component ratio of the pore-forming agent and further increasing the addition amount, the framework pores in this example further increase, and the cathode penetration amount increases, and the performance is further improved.

[0080] Example 4:

[0081] A preparation method of a PCFC with a porous skeleton infiltration self-assembled cathode. First, a PCFC matrix with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0082] (1) Preparation of the porous skeleton: Mix 29 g of PMMA microspheres, 6 g of soluble starch, 15 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a skeleton slurry; Immerse the skeleton slurry once on the electrolyte surface of the PCFC matrix, dry and then sinter. The sintering temperature is 1450 °C, the heating rate is 4 °C / min, and the holding time is 5 h;

[0083] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF and 8 g of ethylene glycol and then ball mill;

[0084] (3) Seal both ends of the half-cell with polytetrafluoroethylene green tape, only expose the skeleton area; Then immerse it in the infiltration liquid, perform ultrasonic-assisted infiltration, the frequency is 40 kHz, the treatment time in the ultrasonic field is 10 minutes, dry and then sinter once. The sintering temperature is 950 °C, the heating rate is 2 °C / min, and the holding time is 2 h.

[0085] Perform performance testing on the PCFC prepared in this example. Its peak power density at 450 °C is 0.15 W·cm -2 . Compared with Example 3, in this example, due to a significant increase in the amount of pore-forming agent added, the number of pores in the skeleton increases, resulting in a decrease in the connectivity between the skeletons. Therefore, the cathode penetration amount decreases, and thus the performance deteriorates.

[0086] Example 5:

[0087] A preparation method of a PCFC with a porous skeleton infiltration self-assembled cathode. First, a PCFC matrix with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0088] (1) Preparation of the porous skeleton: Mix 19 g of PMMA microspheres, 6 g of soluble starch, 25 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a skeleton slurry; Immerse the skeleton slurry twice on the electrolyte surface of the PCFC matrix, dry and then sinter. The sintering temperature is 1450 °C, the heating rate is 3 °C / min, and the holding time is 5 h;

[0089] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF and 12 g of ethylene glycol and then ball mill;

[0090] (3) Seal both ends of the half-cell with PTFE tape, exposing only the skeleton area; then immerse it in the infiltration liquid and perform ultrasonic-assisted infiltration at a frequency of 50 kHz for 20 minutes in the ultrasonic field. After drying, sinter it once at a sintering temperature of 1000 °C, a heating rate of 3 °C / min, and a holding time of 5 h.

[0091] Perform performance tests on the PCFC prepared in this example. Its peak power density at 450 °C is 0.13 W·cm -2 . As Figure 2 shown in (a), it is a SEM cross-section diagram of the porous skeleton infiltrated cathode. Compared with Example 3, in this example, due to the increase in the impregnation times of the skeleton slurry, the skeleton becomes thicker and the connectivity between the skeletons increases. However, a single ultrasonic infiltration fails to increase the cathode penetration, so the performance decreases.

[0092] Example 6

[0093] A preparation method of a PCFC with a porous skeleton infiltrated self-assembled cathode. First, obtain a PCFC substrate with an electrolyte loaded on an anode support, and then perform the following steps:

[0094] (1) Preparation of the porous skeleton: Mix 19 g of PMMA microspheres, 6 g of soluble starch, 25 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol by ball milling to prepare a skeleton slurry; Immerse the skeleton slurry on the electrolyte surface of the PCFC substrate 2 times, dry it, and then sinter it at a sintering temperature of 1450 °C, a heating rate of 3 °C / min, and a holding time of 5 h;

[0095] (2) Preparation of the cathode infiltration liquid: Mix 4 g of cathode powder PBSCF with 12 g of ethylene glycol and then ball mill;

[0096] (3) Seal both ends of the half-cell with PTFE tape, exposing only the skeleton area; then immerse it in the infiltration liquid and perform ultrasonic-assisted infiltration at a frequency of 50 kHz for 20 minutes in the ultrasonic field. After drying, sinter it once, and then repeat the ultrasonic infiltration and sintering once at a sintering temperature of 1000 °C, a heating rate of 3 °C / min, and a holding time of 5 h.

[0097] Perform performance tests on the PCFC prepared in this example. As Figure 3 shown, the peak power density at 450 °C is 0.27 W·cm -2 . Figure 3 Among them, j-U represents the relationship between current density and voltage, and j-P represents the relationship between current density and power density. As Figure 2As shown in Fig. (b), the SEM cross-section image of the porous framework infiltrated cathode prepared in this example. Compared with Example 5, the ultrasonic infiltration in this example was carried out twice, which increased the cathode penetration amount, improved the overall ionic conductivity while not hindering the continuity of cathode conduction, so the performance was improved.

[0098] Example 7

[0099] A preparation method of a PCFC with a porous framework infiltrated self-assembled cathode. First, a PCFC substrate with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0100] (1) Preparation of the porous framework: 19 g of PMMA microspheres, 6 g of soluble starch, 25 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol are mixed and ball-milled to prepare a framework slurry; the framework slurry is impregnated twice on the electrolyte surface of the PCFC substrate, dried and then sintered. The sintering temperature is 1450 °C, the heating rate is 3 °C / min, and the holding time is 5 h;

[0101] (2) Preparation of the cathode infiltration liquid: 4 g of cathode powder PBSCF and 8 g of ethylene glycol are mixed and ball-milled;

[0102] (3) Seal both ends of the half-cell with polytetrafluoroethylene green tape, only expose the framework area; then immerse it in the infiltration liquid, carry out ultrasonic-assisted infiltration, the frequency is 50 kHz, the treatment time in the ultrasonic field is 20 minutes, dry and sinter once, and then repeat the ultrasonic infiltration and sintering twice. The sintering temperature is 1000 °C, the heating rate is 3 °C / min, and the holding time is 5 h.

[0103] The PCFC prepared in this example was subjected to performance testing, and its peak power density at 450 °C was 0.12 W·cm -2 . As Figure 2 As shown in Fig. (c), the SEM cross-section image of the porous framework infiltrated cathode prepared in this example. Compared with Example 6, the ultrasonic infiltration in this example was carried out three times, which further increased the cathode penetration amount, but the penetration amount was oversaturated, and too much cathode covered the framework surface, which not only blocked the framework pores, but also the cathode covered on the framework surface was prone to cracking due to the lack of support of the framework when the thermal expansion coefficients did not match, resulting in hindered electron conduction and decreased mass transfer efficiency, affecting the battery performance.

[0104] Example 8

[0105] A preparation method of a PCFC with a porous framework infiltrated self-assembled cathode. First, a PCFC substrate with an electrolyte loaded on an anode support is obtained, and then the following steps are carried out:

[0106] (1) Preparation of the porous skeleton: 19 g of PMMA microspheres, 6 g of soluble starch, 25 g of electrolyte powder BZCYYb, 2 g of polyethylene glycol-30-dihydroxystearate, 1 g of polyethylene glycol, 3 g of polyvinyl butyral, and 100 g of ethanol were mixed and ball-milled to prepare a skeleton slurry; the skeleton slurry was impregnated twice on the surface of the electrolyte of the PCFC matrix, dried and then sintered. The sintering temperature was 1450 °C, the heating rate was 3 °C / min, and the holding time was 5 h;

[0107] (2) Preparation of the cathode infiltration liquid: 0.08 g of a precursor of the active component containing W (tungsten metal) and 3.92 g of cathode powder PBSCF were dissolved in ethanol, mixed evenly and then dried to obtain a mixed powder; 4 g of the mixed powder and 12 g of ethylene glycol were mixed in proportion and then ball-milled;

[0108] (3) Seal both ends of the half-cell with PTFE green tape, only exposing the skeleton area; then immerse it in the infiltration liquid, perform ultrasonic-assisted infiltration, the frequency is 50 kHz, the treatment time in the ultrasonic field is 20 minutes, dry and then sinter once, and repeat the ultrasonic infiltration and sintering once. The sintering temperature is 1000 °C, the heating rate is 3 °C / min, and the holding time is 5 h.

[0109] The PCFC prepared in this example was subjected to performance testing, and its peak power density at 450 °C was 0.75 W·cm -2 . Compared with Example 6, an active component precursor W was added to the cathode infiltration liquid in this example, effectively inhibiting the generation of impurity phases and promoting charge-mass transfer, so the performance was improved.

[0110] To intuitively compare the similarities and differences of each example, the parameter settings and performance test results in each example are shown in Table 1 below.

[0111] Table 1 Parameter settings and performance test results in each example

[0112]

[0113] It can be understood that except for the parameters listed in Table 1, the other condition parameters in each example are basically the same.

[0114] In summary, the PCFCs prepared in each embodiment of the present invention have all achieved the effect of ultimately improving the battery performance by increasing the porosity and the uniformity of pore distribution. By adjusting the proportion and quality of the pore-forming agent, the addition of active components, the time of ultrasonic treatment, and the number of times of skeleton impregnation and ultrasonic infiltration, PCFCs with corresponding performances that can meet different application scenarios can be obtained. The comparison of each example also proves the effectiveness of the improved operation of the method of the present invention.

[0115] Those of ordinary skill in the art can understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a PCFC with a porous framework infiltrated self-assembled cathode, characterized in that, Comprising: Obtaining a PCFC substrate with an electrolyte supported on an anode support; Preparing a porous framework, which includes: mixing a pore-forming agent, a proton-conducting electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol and ball-milling them to prepare a framework slurry; impregnating the framework slurry on the surface of the electrolyte of the PCFC substrate, and co-sintering after drying to obtain a half-cell with a framework structure; The pore-forming agent includes PMMA microspheres and soluble starch; The particle size of the PMMA microspheres is 1 - 10 μm, and the particle size of the soluble starch is 50 - 200 nm; Preparing a cathode infiltration liquid, which includes: dissolving a cathode powder or the cathode powder and an active component precursor in ethanol, mixing evenly and drying to obtain a mixed powder; mixing the mixed powder and ethylene glycol in a certain proportion and ball-milling to prepare an infiltration liquid; Sealing both ends of the half-cell, then immersing it in the infiltration liquid for ultrasonic-assisted infiltration, drying and sintering; repeating the infiltration and sintering multiple times until a preset loading amount is reached to obtain the PCFC.

2. The preparation method according to claim 1, wherein the mass ratio of the PMMA microspheres to the soluble starch is 3:1 - 1:

1.

3. The preparation method according to claim 1, characterized in that The mass ratio of the pore-forming agent, the proton-conducting electrolyte powder, polyethylene glycol-30-dihydroxystearate, polyethylene glycol, polyvinyl butyral, and ethanol is (5 - 45):(5 - 45):2:1:3:

100.

4. The preparation method according to claim 1, wherein The active component precursor is one or more of transition metals, transition metal oxides, rare earth metals, and rare earth metal oxides.

5. The preparation method according to claim 1, characterized in that, When the framework slurry is impregnated on the surface of the tubular PCFC electrolyte and co-sintered after drying, the sintering temperature is 1200 - 1450 °C, the heating rate is 1 - 5 °C / min, and the holding time is 4 - 10 h.

6. The preparation method according to claim 1, wherein During the ultrasonic-assisted infiltration, the ultrasonic frequency is 40 - 60 kHz, and the ultrasonic treatment time is 10 - 30 minutes.

7. The preparation method according to claim 1, characterized in that, The proton-conducting electrolyte powder uses BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; The cathode powder uses PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ .

8. The preparation method of the porous framework infiltration self-assembly cathode according to claim 1, characterized in that, The mass ratio of the mixed powder to ethylene glycol is 1:(2 - 5); The mass of the active component precursor is 1% - 10% of the mass of the cathode powder.

9. The preparation method of the porous framework infiltration type self-assembled cathode according to claim 1, characterized in that When immersed in the infiltration liquid for ultrasonic-assisted infiltration, dried and sintered, the sintering temperature is 900 - 1000 °C, the heating rate is 1 - 5 °C / min, and the holding time is 2 - 5 h.

10. A PCFC with a porous framework infiltrated self-assembled cathode prepared by the preparation method according to any one of claims 1 to 9.

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