An apparatus and method for preparing a solid electrolyte membrane based on Joule heating technology

Abstract

This invention discloses a device and method for preparing a solid electrolyte membrane based on Joule heating technology, belonging to the field of battery materials technology. The device includes a main body; a Joule heating element is disposed in the inner cavity of the main body; several slide rails are disposed on both sides of the Joule heating element, and the slide rails are fixedly connected to the inner wall of the main body; a temperature sensor that can slide vertically is disposed on the slide rail; the Joule heating element includes a heat-insulating sleeve, which is a hollow cylindrical structure with open ends; a detachable support is connected to the bottom of the heat-insulating sleeve; a semi-circular positive electrode interface and a negative electrode interface are respectively connected to both sides of the heat-insulating sleeve; pressure relief and temperature measurement holes are also provided on the side wall of the heat-insulating sleeve; an internal thread is provided on the upper inner wall of the heat-insulating sleeve for threaded connection with a pressure head; a ceramic preform is installed in the inner cavity of the heat-insulating sleeve; pads are disposed on both sides of the ceramic preform. This invention can achieve rapid densification and crystallization of the ceramic preform to obtain a high-performance solid electrolyte membrane.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology and relates to an apparatus and method for preparing a solid electrolyte membrane based on Joule heating technology. Background Technology

[0002] Rapid socio-economic growth has led to a sustained and rapid increase in energy consumption. Traditional fossil fuel reserves are limited, and their production and application pose serious environmental pollution problems. Therefore, developing and utilizing clean and renewable energy sources to replace coal and fossil fuels, and constructing a green and low-carbon energy system, has become a highly promising research direction. The main challenge in grid-connected power supply and deep application of clean energy lies in developing safe and efficient energy storage devices. While lithium batteries, as the most widely used electrochemical energy storage device, possess high energy density and long cycle life, they perform poorly in extreme thermal and mechanical environments, limiting their deep application in industrial production and transportation. Using inorganic solid-state electrolytes with high Young's modulus and wide electrochemical windows to replace unstable membrane / electrolyte systems can help construct high-performance lithium batteries that can operate at high power under all climate conditions, enabling technological empowerment and contributing to the transformation of the green energy system.

[0003] Traditional solid-state electrolyte (SSE) preparation methods using high-temperature solid-state sintering are time-consuming and energy-intensive, lacking precise control over grain growth. This often results in abnormal grain growth and significant inhomogeneity at the grain interface. Prolonged sintering times also lead to severe lithium volatilization, accompanied by the formation of electrolyte impurity phases, such as metastable crystal structures or abnormal secondary phases. This weakens the electrolyte's ionic conductivity, reduces its structural density, and further increases the risk of lithium dendrite growth and penetration. Ultrafast Sintering Technology, as a novel strategy for SSE membrane preparation, rapidly achieves the crystallization and densification of the SSE preform through "flash sintering," reducing unnecessary lithium volatilization and production energy consumption. The transient high temperature achieved in an inert atmosphere helps remove volatile impurities, assists in the formation of a uniform microstructure in ceramic particles, ensures structural consistency, and effectively eliminates irregular defects, demonstrating excellent performance in SSE membrane preparation. It is worth noting that traditional Joule heating elements (carbon felt) have many problems that need to be solved in the process of processing inorganic solid electrolyte preforms, including: (1) poor thermal contact between carbon felt and the rigid surface of ceramic preform, resulting in a deviation between the actual processing temperature and the infrared thermometry value; (2) poor heat preservation effect of porous carbon felt, and the sudden cooling caused by power failure may lead to the formation of microcracks on the surface of the electrolyte sheet; (3) as a disposable consumable, carbon felt results in serious material waste in the process of large-scale preparation of electrolyte membranes; (4) the clamping method between carbon felt and solid electrolyte membrane does not allow for hard surface modification of the electrolyte sheet, such as welding of graphite or alloy layers. In view of this, developing a new type of Joule heating device that is reusable, has high heat preservation effect and good thermal contact, and can realize surface modification function has important scientific research significance and application value. Furthermore, to match this novel Joule heating element and maximize the solution to the problems existing in the preparation of solid electrolyte membranes by Joule heating (such as microcracks generated by thermal shock and membrane quenching failure caused by rapid cooling), a matching novel high-performance solid electrolyte membrane preparation method is developed to achieve a solid electrolyte membrane with high structural density, high ionic conductivity, and a high-performance modified layer. This method has extremely important scientific research value and commercial significance for the promotion of Joule heating technology and the mass production of solid electrolyte membranes. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of poor thermal contact, poor heat preservation effect, material waste, and inability to achieve surface modification of rigid electrolyte membranes in the preparation of solid electrolyte membranes by Joule heating devices in the prior art, and to provide a device and method for preparing solid electrolyte membranes based on Joule heating technology.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a device for preparing a solid electrolyte membrane based on Joule heating technology, comprising a main body; an air inlet and a first airtight manifold are provided on one side of the main body, the airtight manifold being used to connect to the positive electrode line; an air vent and a second airtight manifold are provided on the other side of the main body, the second airtight manifold being used to connect to the negative electrode line and the ground line; a Joule heating element is provided in the inner cavity of the main body; several slide rails are provided on both sides of the Joule heating element, the slide rails being fixedly connected to the inner wall of the main body; a temperature sensor that can slide in the vertical direction is provided on the slide rail; the Joule heating element includes a heat insulation sleeve, the heat insulation sleeve being a hollow cylindrical structure with open ends; a detachable support is connected to the bottom of the heat insulation sleeve; a semi-circular positive electrode line interface and a negative electrode line interface are respectively connected to both sides of the heat insulation sleeve; pressure relief and temperature measurement holes are also provided on the side wall of the heat insulation sleeve; an internal thread is provided on the upper inner wall of the heat insulation sleeve for threaded connection with a pressure head; a ceramic blank is installed in the inner cavity of the heat insulation sleeve; pads are provided on both sides of the ceramic blank.

[0007] Furthermore, a lubricating layer is provided between the ceramic blank and the pad.

[0008] Furthermore, the pad is a grooved graphite pad or a non-grooved graphite pad; the grooves in the grooved graphite pad are used to hold the modified powder; the lubricating layer is nano-grade high-purity graphite powder.

[0009] Furthermore, the main body includes a heat-insulating filling layer and an insulating layer arranged sequentially from the outside to the inside; the surface of the insulating layer on the inner wall of the main body is also coated with a heat-reflective coating; and the bottom surface inside the main body is paved with refractory bricks.

[0010] Furthermore, the material of the thermal insulation filling layer is expanded polystyrene board, extruded polystyrene board, sprayed polyurethane or polystyrene particle mortar; the material of the insulation layer is plastic, rubber or ceramic.

[0011] Furthermore, the refractory brick is made of alumina, zirconium oxide, silicon nitride, or boron nitride; the heat-reflective coating is made of nanodiamond particles, spinel nanoparticles, silicon dioxide nanoparticles, or polyvinyl alcohol.

[0012] Furthermore, the material of the pressure head is iron, tungsten, titanium alloy, alloy steel, graphite, silicon, or amorphous carbon; the material of the ceramic body is an oxide material, a sulfide material, or a halide material.

[0013] Secondly, the present invention provides a method for preparing a solid electrolyte membrane based on Joule heating technology using the above-mentioned device, comprising the following steps:

[0014] S1, mix the raw materials for preparing the solid electrolyte membrane, add ball milling media and ball mill; dry and calcine the powder obtained by ball milling, then add sintering aid and repeat the ball milling steps; and dry, grind and sieve the obtained powder in sequence to obtain fine electrolyte powder.

[0015] S2, The electrolyte powder is placed into an alloy pressing mold, and a hydraulic press is used to press the electrolyte powder into a ceramic green body;

[0016] S3, place the ceramic green body into a crucible and perform stress-relief annealing to eliminate residual stress and obtain a structurally stable ceramic green body;

[0017] S4, the ceramic blank obtained in S3 is clamped in the Joule heating element by a pad, the inner cavity of the main body is evacuated, and then an atmosphere is introduced; then a solid electrolyte membrane is obtained through multi-stage heating and cooling.

[0018] Further, the raw materials in S1 are a mixture of various metal oxides, ammonium phosphates, aluminum nitrates, lithium carbonate, lithium hydroxide, tetrabutyl titanate, and aluminum acetate dihydrate; the ball milling media are one or more mixtures of water, anhydrous ethanol, and isopropanol; the ball milling speed is 100 r / min to 1000 r / min; the peak temperature of the calcination treatment is 100℃ to 1000℃, and the heating and cooling rate of the calcination treatment is 1℃ / min to 20℃ / min; the sintering aid is one or more mixtures of silicon dioxide, lithium borate, boron nitride, lithium fluoride, alumina, and lithium nitride, and the mass percentage of the sintering aid in the powder is 0.1wt% to 2wt%; the sieve used in the sieving process is one or more of 100 mesh to 1000 mesh.

[0019] Further, in step S2, the powder mass placed in the alloy pressing mold is 0.1g to 0.9g; the hydraulic press pressure range is 1MPa to 100MPa, and the pressurization method is continuous or intermittent pressurization; in step S3, the annealing holding temperature is 100℃ to 1000℃, the heating rate is 1℃ / min to 20℃ / min, and the cooling rate is 1℃ / min to 10℃ / min; in step S4, the Joule heating voltage is 10V to 100V, the heating current is 1A to 100A, and the peak heating temperature is 100℃ to 1000℃; the heating atmosphere is one or more of nitrogen, argon, hydrogen, oxygen, and air.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention discloses an apparatus and method for preparing a solid electrolyte membrane based on Joule heating technology. A pressure head provides axial pressure to ensure uniform heating of the ceramic preform during the heating process. An insulating jacket provides multiple layers of protection for the internal temperature environment, preventing sudden cooling of the cavity after power failure of the Joule heating device. This invention achieves rapid densification and crystallization of the ceramic preform using Joule heating technology, efficiently obtaining a high-performance solid electrolyte membrane with a dense structure and high ionic conductivity. The solid electrolyte membrane prepared by this invention exhibits high mechanical strength, good product consistency, and high ionic conductivity (up to 7 × 10⁻⁶). -4 With an efficiency (S / cm), it exhibits excellent overall performance. This technology is of significant scientific importance for the development of high-performance solid-state batteries suitable for all climates, and can also significantly improve the production efficiency and reduce production costs of current solid-state electrolyte membrane products.

[0022] Furthermore, the lubricating layer achieved by the nano-grade high-purity graphite powder of this invention, together with the highly smooth, groove-free graphite pad, ensures that the Joule heating element has the characteristics of normal disassembly and reusability, avoiding the material waste caused by traditional Joule heating elements (carbon felt) in the process of mass production of electrolyte membranes.

[0023] Furthermore, the present invention includes a thermal insulation filling layer coated with a heat-reflective coating to further maintain the internal temperature of the chamber, reduce heat loss, ensure uniform heating of the ceramic blank during the heating process, and improve the production efficiency and yield of the electrolyte membrane. The insulation layer also isolates the electrical environment, ensuring the safety of the chamber.

[0024] Furthermore, the grooved graphite pad can support powder raw materials used for thermal welding to achieve surface modification of hard films, enabling integrated modification of electrolyte membranes. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the Joule heating element of the present invention.

[0028] Wherein: 1-Air inlet; 2-Insulation filling layer; 3-Insulation layer; 4-First airtight manifold; 5-Positive wire; 6-Temperature sensor; 7-Joule heating element; 8-Second airtight manifold; 9-Negative wire; 10-Ground wire; 11-Vent port; 12-Slide rail; 13-Refractory brick; 14-Heat reflective coating; 15-Bottom support; 16-Ceramic body; 17-Lubricating layer; 18-Positive wire interface; 19-Insulation sleeve; 20-Pressure head; 21-Pressure relief and temperature measuring hole; 22-Groove graphite pad; 23-Ungroove graphite pad; 24-Negative wire interface. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] See Figure 1 and Figure 2 This invention discloses an apparatus for preparing a solid electrolyte membrane based on Joule heating technology, comprising a main body; an air inlet 1 and a first airtight manifold 4 are provided on one side of the main body, the airtight manifold 4 being used to connect to the positive electrode line 5; an air outlet 11 (vacuum pump interface) and a second airtight manifold 8 are provided on the other side of the main body, the second airtight manifold 8 being used to connect to the negative electrode line 9 and the ground line 10; a Joule heating element 7 is provided in the inner cavity of the main body; a plurality of slide rails 12 are provided on both sides of the Joule heating element 7, the slide rails 12 being fixedly connected to the inner wall of the main body; temperature sensors that can slide vertically are provided on the slide rails 12. Sensor 6; The Joule heating element 7 includes a heat insulation sleeve 19, which is a hollow cylindrical structure with openings at both ends; a detachable support 15 is connected to the bottom of the heat insulation sleeve 19; a semi-circular positive electrode interface 18 and a negative electrode interface 24 are respectively connected to the two sides of the heat insulation sleeve 19; a pressure relief and temperature measuring hole 21 is also provided on the side wall of the heat insulation sleeve 19; an internal thread is provided on the upper inner wall of the heat insulation sleeve 19 for threaded connection with the pressure head 20 to provide appropriate pressure and prevent the ceramic body 16 from deforming during sintering; the ceramic body 16 is installed in the inner cavity of the heat insulation sleeve 19; pads are provided on both sides of the ceramic body 16.

[0037] In one feasible embodiment of the present invention, a lubricating layer 17 is further provided between the ceramic blank 16 and the pad. The lubricating layer 17 is nano-grade high-purity graphite powder.

[0038] In one feasible embodiment of the present invention, the pad is a grooved graphite pad 22 or a non-grooved graphite pad 23; the groove in the grooved graphite pad 22 is used to hold the modified powder; wherein the part of the non-grooved graphite pad 23 that is in direct contact with the surface of the phosphate solid electrolyte membrane is polished smooth with ultra-high grit sandpaper to prevent it from sticking to the lubrication layer 17.

[0039] In one feasible embodiment of the present invention, the main body includes a heat-insulating filling layer 2 and an insulating layer 3 arranged sequentially from the outside to the inside; the surface of the insulating layer 3 on the inner wall of the main body is also coated with a heat-reflective coating 14; and the bottom surface inside the main body is paved with refractory bricks 13.

[0040] In one feasible embodiment of the present invention, the thermal insulation filling layer 2 is made of materials including but not limited to foamed polystyrene board, extruded polystyrene board, sprayed polyurethane, or polystyrene particle mortar; the insulation layer 3 is made of materials including but not limited to plastics such as polyvinyl chloride, polyethylene, and nylon, rubbers such as neoprene rubber, acrylic rubber, and silicone rubber, and ceramics, to isolate the current environment and ensure the safety of the enclosure. The infrared temperature sensor 6 is an infrared temperature sensor, clamped on the slide rail 12, and its vertical position can be adjusted. It measures the internal temperature of the sintering cavity in situ through the pressure relief and temperature measuring hole 21.

[0041] In one feasible embodiment of the present invention, the refractory brick 13 is made of materials such as alumina, zirconium oxide, silicon nitride or boron nitride, and is used to support the Joule heating element 7; the heat reflective coating 14 is made of, but is not limited to, nanodiamond particles, spinel nanoparticles, silicon dioxide nanoparticles or polyvinyl alcohol, and is used to reflect the heat rays generated by Joule heating, so as to achieve an internal heat preservation effect.

[0042] In one feasible embodiment of the present invention, the pressure head 20 is made of materials such as iron, tungsten, titanium alloy, alloy steel, graphite, silicon or amorphous carbon; the ceramic body 16 is made of oxide materials, sulfide materials or halide materials.

[0043] This invention discloses a method for preparing a solid electrolyte membrane based on Joule heating technology using the above-mentioned device, comprising the following steps:

[0044] S1, mix the raw materials for preparing the solid electrolyte membrane, add ball milling media and ball mill; dry and calcine the powder obtained by ball milling, then add sintering aid and repeat the ball milling steps; and dry, grind and sieve the obtained powder in sequence to obtain fine electrolyte powder.

[0045] S2, The electrolyte powder is placed into an alloy pressing mold, and a hydraulic press is used to press the electrolyte powder into a ceramic green body;

[0046] S3, place the ceramic green body into a crucible and perform stress-relief annealing to eliminate residual stress and obtain a structurally stable ceramic green body;

[0047] S4, the ceramic blank obtained in S3 is clamped in the Joule heating element 7 by a pad, the inner cavity of the main body is evacuated, and then an atmosphere is introduced; then a solid electrolyte membrane is obtained through multi-stage heating and cooling.

[0048] In one feasible embodiment of the present invention, the raw material in S1 is a mixture of various metal oxides, ammonium phosphate, aluminum nitrate, lithium carbonate, lithium hydroxide, tetrabutyl titanate, and aluminum acetate dihydrate; the ball milling medium is one or more mixtures of water, anhydrous ethanol, and isopropanol; the ball milling speed is 100 r / min to 1000 r / min; the peak temperature of the calcination treatment is 100℃ to 1000℃, and the heating and cooling rate of the calcination treatment is 1℃ / min to 20℃ / min; the sintering aid is one or more mixtures of silicon dioxide, lithium borate, boron nitride, lithium fluoride, alumina, and lithium nitride, and the mass percentage of the sintering aid in the powder is 0.1wt% to 2wt%; the sieve used in the sieving process is one or more of 100 mesh to 1000 mesh.

[0049] In one feasible embodiment of the present invention, the powder mass placed in the alloy pressing mold in step S2 is 0.1g to 0.9g; the hydraulic press pressure range is 1MPa to 100MPa, and the pressurization method is continuous or intermittent pressurization; the annealing holding temperature in step S3 is 100℃ to 1000℃, the heating rate is 1℃ / min to 20℃ / min, and the cooling rate is 1℃ / min to 10℃ / min; the crucible material can be one of quartz, clay, corundum, alumina, zirconium silicate, and zirconium oxide; the Joule heating voltage in step S4 is 10V to 100V, the heating current is 1A to 100A, and the peak heating temperature is 100℃ to 1000℃; the heating atmosphere is one or more of nitrogen, argon, hydrogen, oxygen, and air.

[0050] Example 1:

[0051] A method for preparing a solid electrolyte membrane includes the following steps:

[0052] Step 1: Take a certain amount of NASICON solid electrolyte powder, put it into a grinding jar and add zirconia balls of different sizes, then place it in a symmetrical position in a ball mill. Select a ball milling speed of 150 r / min and continue grinding for 12 h. After grinding, calcine the powder. The peak calcine temperature is 800℃, and the heating and cooling rates are both set to 16℃ / min.

[0053] Step 2: Take the powder obtained from calcination in Step 1 and add sintering aids: nano lithium nitride powder (mass of 0.1% of the NASICON solid electrolyte powder) and nano alumina powder (mass of 0.1% of the NASICON solid electrolyte powder). Repeat the ball milling step after mixing the powder, add zirconium oxide balls of different sizes and ball mill for 8 hours.

[0054] Step 3: Take the powder obtained in step 2, add it to a beaker, place it in an oven and dry it at 60°C for 1 hour. Grind it in a mortar for 10 minutes, and then sieve it through a 100-mesh sieve to obtain a fine powder.

[0055] Step 4: Take 0.15g of the powder prepared above, flatten it using an alloy pressing mold, then place the mold on the jack platform. Rotate the pressure button to apply pressure to 1MPa, releasing the pressure the instant it is reached. After releasing the pressure, remove the mold, invert it, replace the mold base with a transparent cylinder, and place it back on the jack platform. Rotate the pressure button, holding the mold with your hand during pressure application to prevent it from detaching and breaking the pressed sheet. Then remove the mold, take out the pressed sheet, and obtain the ceramic green body.

[0056] Step 5: Place the pressed tablet from Step 4 into a firing crucible, place it in a high-temperature resistance box, set the firing temperature to 800℃, set the temperature rise rate to 10℃ per minute, hold at the highest temperature for 120 minutes, and set the temperature drop rate to 15℃ per minute.

[0057] Step 6: Take the pre-treated tablet from Step 5 and place it into the graphite heating mold. Clamp the mold in the Joule heating device 7. Set the heating voltage to 70V and the heating current to 80A. After setting, close the air inlet channel, open the air pump channel, and start the air pump to ensure that the device is in a vacuum state. Then close the air pump and air pump channel, open the nitrogen channel, and fill the device with nitrogen until the pressure gauge reading stabilizes. Then close the nitrogen channel.

[0058] Step 7: Open the control panel of the Joule heating device 7 and set two heating zones and two cooling zones. For the first heating zone, set the maximum heating temperature to 700℃ and hold it for 1 minute after reaching the maximum temperature. For the second heating zone, set the maximum heating temperature to 1000℃ and hold it for 1 minute after reaching the maximum temperature. For the first cooling zone, set the minimum cooling temperature to 400℃ and hold it for 1 minute after reaching the minimum temperature.

[0059] For the second cooling interval, directly turn off the power after the first cooling interval ends, so that the power supply current is 0A, then open the device and take out the tablet.

[0060] The above steps yield a NASICON solid electrolyte membrane with high mechanical strength and excellent electrochemical performance. The resulting solid electrolyte membrane exhibits reduced volume, increased density, and significantly enhanced hardness. Performance testing of the prepared solid electrolyte membrane revealed that its mechanical strength is approximately four times that of NASICON solid electrolyte sheets sintered in a conventional high-temperature resistance oven, and it also possesses good ionic conductivity of 5 × 10⁻⁶. -4 On the order of S / cm.

[0061] Example 2:

[0062] Step 1: Take a certain amount of LATP powder, put it into a grinding jar and add zirconium oxide balls of different sizes, then place it in a symmetrical position in a ball mill. The ball milling speed is 500 r / min, and the grinding is carried out for 4 hours. After grinding, the powder is calcined. The peak calcination temperature is 400℃, and the heating and cooling rates are both set to 8℃ / min.

[0063] Step 2: Take the calcined powder from Step 1 and add sintering aids: nano lithium nitride powder (0.5% of LATP by mass) and nano lithium borate powder (0.8% of LATP by mass). Ball mill the mixed powder for 2 hours.

[0064] Step 3: Take out the powder obtained from ball milling in step 2 and add it to a beaker. Place the beaker in an oven and dry it at 60°C for 1 hour. Grind it in a mortar for 10 minutes and then sieve it through a 600-mesh sieve to obtain a fine powder.

[0065] Step 4: Take 0.3g of the powder prepared above, flatten the powder using an alloy pressing mold, and then place the mold into the jack platform. Set the pressure to 25MPa. After pressing is complete, remove the mold, take out the ceramic sheet, and obtain the ceramic green body.

[0066] Step 5: Place the ceramic green body from Step 4 into a firing crucible, place it in a high-temperature resistance box, set the firing temperature to 350℃, set the temperature rise rate to 7℃ per minute, hold at the highest temperature for 120 minutes, and set the temperature drop rate to 7℃ per minute.

[0067] Step 6: Take the pre-treated tablet from Step 5 and place it into the graphite heating mold. Clamp the mold in the Joule heating device 7. Set the heating voltage to 30V and the heating current to 45A. After setting, close the inlet gas channel, open the gas pump channel, and start the gas pump to ensure that the device is in a vacuum state. Then, close the gas pump and gas pump channel, open the argon gas channel, and fill the device with argon gas until the pressure gauge reading stabilizes. Then, close the argon gas channel.

[0068] Step 7: Open the control panel of the Joule heating device 7 and set two heating zones and two cooling zones. For the first heating zone, set the maximum heating temperature to 400℃ and hold it for 1 minute after reaching the maximum temperature. For the second heating zone, set the maximum heating temperature to 600℃ and hold it for 1 minute after reaching the maximum temperature. For the first cooling zone, set the minimum cooling temperature to 400℃ and hold it for 1 minute after reaching the minimum temperature.

[0069] For the second cooling interval, directly turn off the power after the first cooling interval ends, so that the power supply current is 0A, then open the device and take out the tablet.

[0070] The above steps yield a LATP solid electrolyte membrane with high hardness and good electrochemical performance. The prepared solid electrolyte membrane exhibits significant volume reduction and enhanced density. Performance testing of the prepared solid electrolyte sheet revealed that its mechanical strength is approximately twice that of LATP solid electrolyte membranes obtained by sintering in a conventional high-temperature resistance oven, and it also possesses good ionic conductivity of 6 × 10⁻⁶. -4 S / cm.

[0071] Example 3:

[0072] Step 1: Take a certain amount of LAGP powder, put it into a grinding jar and add a certain number of zirconia balls. Place the grinding jar in a symmetrical position in the ball mill. Select a ball milling speed of 120 r / min and grind for 12 h. After grinding, calcine the powder. The peak calcination temperature is 150℃ and the heating and cooling rates are both set to 5℃ / min.

[0073] Step 2: Take the powder obtained from calcination in Step 1 and add sintering aids: nano lithium nitride powder (1.2% of LAGP powder by mass) and nano lithium fluoride powder (2.0% of LAGP powder by mass), mix evenly, and ball mill at the same speed for 8 hours.

[0074] Step 3: Transfer the powder obtained from ball milling in step 2 to a beaker, place the beaker in an oven and dry it at 60°C for 1 hour, grind the powder with a mortar and pestle for 10 minutes, and then sieve it through an 800-mesh sieve to obtain fine powder.

[0075] Step 4: Take 0.7g of the powder prepared above each time, use an alloy pressing mold to flatten the powder, then place the mold on the jack platform, rotate the pressure button to apply pressure to 70MPa. After pressing, remove the mold, take out the pressed sheet, and obtain the ceramic green body.

[0076] Step 5: Place the pressed tablet from Step 4 into a firing crucible, place it in a high-temperature resistance box, set the firing temperature to 150℃, set the temperature rise rate to 3℃ per minute, hold at the highest temperature for 120 minutes, and set the temperature drop rate to 5℃ per minute.

[0077] Step 6: Take the pre-treated tablet from Step 5 and place it into the graphite heating mold. Clamp the mold in the Joule heating device 7. Set the heating voltage to 15V and the heating current to 5A. After setting, close the inlet gas channel, open the gas pump channel, and start the gas pump to ensure that the device is in a vacuum state. Then close the gas pump and gas pump channel, open the nitrogen and argon channels, and fill the device with a mixture of nitrogen and argon gas until the pressure gauge reading stabilizes. Then close the nitrogen and argon channels.

[0078] Step 7: Open the control panel of the Joule heating device 7 and set two heating zones and two cooling zones. For the first heating zone, set the maximum heating temperature to 200℃ and hold it for 1 minute after reaching the maximum temperature. For the second heating zone, set the maximum heating temperature to 300℃ and hold it for 1 minute after reaching the maximum temperature. For the first cooling zone, set the minimum cooling temperature to 200℃ and hold it for 1 minute after reaching the minimum temperature.

[0079] For the second cooling interval, directly turn off the power after the first cooling interval ends, so that the power supply current is 0A, then open the device and take out the tablet.

[0080] The above steps yield a LAGP solid electrolyte membrane with high mechanical strength and a wide electrochemical window. The prepared solid electrolyte membrane has a significantly smaller volume and increased density compared to the ceramic green body. Performance testing of the prepared solid electrolyte membrane revealed that its mechanical strength is approximately 1.2 times that of the LATP solid electrolyte membrane obtained by sintering in a conventional high-temperature resistance oven, and it also exhibits good ionic conductivity of 3 × 10⁻⁶. -4 S / cm.

[0081] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An apparatus for preparing a solid electrolyte membrane based on Joule heating technology, characterized in that, The system includes a main body; one side of the main body is provided with an air inlet (1) and a first airtight manifold (4), the airtight manifold (4) being used to connect to the positive electrode line (5); the other side of the main body is provided with an air outlet (11) and a second airtight manifold (8), the second airtight manifold (8) being used to connect to the negative electrode line (9) and the ground wire (10); the inner cavity of the main body is provided with a Joule heating element (7); several slide rails (12) are provided on both sides of the Joule heating element (7), the slide rails (12) being fixedly connected to the inner wall of the main body; a temperature sensor (6) that can slide in the vertical direction is provided on the slide rail (12); the... The Joule heating element (7) includes a heat insulation sleeve (19), which is a hollow cylindrical structure with open ends; a detachable support (15) is connected to the bottom of the heat insulation sleeve (19); a semi-circular positive electrode interface (18) and a negative electrode interface (24) are connected to the two sides of the heat insulation sleeve (19); a pressure relief and temperature measuring hole (21) is also provided on the side wall of the heat insulation sleeve (19); an internal thread is provided on the upper inner wall of the heat insulation sleeve (19) for threaded connection with the pressure head (20); a ceramic blank (16) is installed in the inner cavity of the heat insulation sleeve (19); pads are provided on both sides of the ceramic blank (16).

2. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 1, characterized in that, A lubricating layer (17) is also provided between the ceramic blank (16) and the pad.

3. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 2, characterized in that, The pad is a grooved graphite pad (22) or a non-grooved graphite pad (23); the groove in the grooved graphite pad (22) is used to hold the modified powder; the lubricating layer (17) is nano-grade high-purity graphite powder.

4. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 1, characterized in that, The main body includes a heat-insulating filling layer (2) and an insulating layer (3) arranged sequentially from the outside to the inside; the surface of the insulating layer (3) on the inner wall of the main body is also coated with a heat-reflective coating (14); the bottom surface inside the main body is covered with refractory bricks (13).

5. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 4, characterized in that, The insulation filling layer (2) is made of foamed polystyrene board, extruded polystyrene board, sprayed polyurethane or polystyrene particle mortar; the insulation layer (3) is made of plastic, rubber or ceramic.

6. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 5, characterized in that, The refractory brick (13) is made of alumina, zirconium oxide, silicon nitride or boron nitride; the heat reflective coating (14) is made of nanodiamond particles, spinel nanoparticles, silicon dioxide nanoparticles or polyvinyl alcohol.

7. The apparatus for preparing a solid electrolyte membrane based on Joule heating technology according to claim 6, characterized in that, The pressure head (20) is made of iron, tungsten, titanium alloy, alloy steel, graphite, silicon or amorphous carbon; the ceramic body (16) is made of oxide, sulfide or halide materials.

8. A method for preparing a solid electrolyte membrane based on Joule heating technology using the apparatus described in any one of claims 1-7, characterized in that, Includes the following steps: S1, mix the raw materials for preparing the solid electrolyte membrane, add ball milling media and ball mill; dry and calcine the powder obtained by ball milling, then add sintering aid and repeat the ball milling steps; and dry, grind and sieve the obtained powder in sequence to obtain fine electrolyte powder. S2, The electrolyte powder is placed into an alloy pressing mold, and a hydraulic press is used to press the electrolyte powder into a ceramic green body; S3, place the ceramic green body into a crucible and perform stress-relief annealing to eliminate residual stress and obtain a structurally stable ceramic green body; S4, the ceramic blank obtained in S3 is clamped in the Joule heating element (7) by a pad, the inner cavity of the main body is evacuated, and then an atmosphere is introduced; then a solid electrolyte membrane is obtained by multi-stage heating and cooling.

9. A method for preparing a solid electrolyte membrane based on Joule heating technology according to claim 8, characterized in that, The raw materials in S1 are a mixture of various metal oxides, ammonium phosphates, aluminum nitrates, lithium carbonate, lithium hydroxide, tetrabutyl titanate, and aluminum acetate dihydrate; the ball milling media are one or more mixtures of water, anhydrous ethanol, and isopropanol; the ball milling speed is 100 r / min to 1000 r / min; the peak temperature of the calcination treatment is 100℃ to 1000℃, and the heating and cooling rate of the calcination treatment is 1℃ / min to 20℃ / min; the sintering aid is one or more mixtures of silicon dioxide, lithium borate, boron nitride, lithium fluoride, alumina, and lithium nitride, and the mass percentage of the sintering aid in the powder is 0.1wt% to 2wt%; the sieve used in the sieving process is one or more of 100 mesh to 1000 mesh.

10. The method for preparing a solid electrolyte membrane based on Joule heating technology according to claim 9, characterized in that, In step S2, the powder mass placed in the alloy pressing mold is 0.1g to 0.9g; the hydraulic press pressure range is 1MPa to 100MPa, and the pressurization method is continuous or intermittent pressurization; in step S3, the annealing holding temperature is 100℃ to 1000℃, the heating rate is 1℃ / min to 20℃ / min, and the cooling rate is 1℃ / min to 10℃ / min; in step S4, the Joule heating voltage is 10V to 100V, the heating current is 1A to 100A, and the peak heating temperature is 100℃ to 1000℃; the heating atmosphere is one or more of nitrogen, argon, hydrogen, oxygen, and air.

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