Preparation method of high-temperature-resistant solid-state electrolyte film and application thereof in integrated solid-state battery

Abstract

The application relates to a preparation method of a high-temperature-resistant solid-state electrolyte film and application of the high-temperature-resistant solid-state electrolyte film in integrated solid-state batteries, and belongs to the technical field of batteries. The specific scheme is as follows: preparation of a meltable solid-state electrolyte, preparation of a high-temperature-resistant composite electrolyte film of an inorganic binder, preparation of a carbon-free alloyable negative electrode, and integrated preparation of a high-temperature-resistant solid-state battery. The preparation of the high-temperature-resistant composite electrolyte film of the inorganic binder comprises three systems of sulfides, oxides and halides, and suitable electrolyte films or combinations thereof can be selected according to the differences of the positive and negative electrodes of the battery. The integrated preparation of the high-temperature-resistant solid-state electrolyte film and the battery in batches improves the battery interface contact, greatly improves the long-term cycle stability of the high-temperature battery, and widens the temperature range of the traditional high-temperature operation battery to the room temperature range or even the range below zero. The application will promote the progress of high-temperature batteries in special fields such as oil drilling, fire warning and commercial spaceflight.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a preparation method of a high-temperature-resistant solid-state electrolyte film and application thereof in integrated solid-state batteries. BACKGROUND

[0002] High-temperature secondary batteries have broad application prospects in the fields of oil drilling, fire warning, commercial spaceflight, etc. At present, the mainstream high-temperature batteries are mostly molten salt batteries, which usually work in the temperature range of 200 DEG C to 600 DEG C. This type of battery has some unique advantages, such as high energy density, good thermal stability and chemical stability, etc. However, they also have some disadvantages and challenges: ① The starting and stopping process of the molten salt high-temperature battery may take a long time, which limits its response speed and flexibility; ② Due to the special materials and complex thermal management system required, the manufacturing and maintenance cost of the molten salt high-temperature battery is relatively high; ③ The molten salt is liquid at high temperature, and if leakage occurs, it may cause serious safety problems; ④ The excessively high working temperature increases the system complexity, while limiting its application scenarios. Therefore, the development of a new type of high-temperature-resistant secondary battery has become the research focus of the power supply of special equipment.

[0003] Inorganic solid-state batteries use high-temperature-resistant inorganic solid-state electrolytes, and have natural high-temperature-resistant operation potential. In addition, compared with molten salt high-temperature batteries, inorganic solid-state batteries have a very wide temperature range from subzero to high temperature, and have broader and more flexible application prospects. However, the batch production of high-temperature-resistant inorganic solid-state batteries first needs to overcome the preparation of high-temperature-resistant solid-state electrolyte films. The traditional solid-state electrolyte film cannot be separated from the polymer organic binder, but at high temperatures, such an organic binder is extremely easy to decompose and react with the solid-state electrolyte, damaging the high-temperature performance of the solid-state battery. Therefore, it is urgent to develop a solid-state electrolyte film preparation method without organic binder to meet the growing demand for high-temperature batteries. SUMMARY

[0004] The purpose of the present application is to solve the problem that the organic binder required for the batch production of traditional inorganic solid-state electrolyte films is easy to decompose at high temperatures, leading to rapid failure of high-temperature batteries, and to provide a preparation method of a high-temperature-resistant solid-state electrolyte film and application thereof in integrated solid-state batteries. By intercrossing a special meltable inorganic solid-state electrolyte with a traditional inorganic solid-state electrolyte (sulfide, oxide, halide solid-state electrolyte) through melt bonding at high temperature, a solid-state electrolyte film with inorganic binder (meltable inorganic solid-state electrolyte) is prepared. In addition, by means of melt infiltration process, the in-situ integrated preparation of the positive electrode and the negative electrode is realized on the basis of the above-mentioned high-temperature-resistant solid-state electrolyte film, which significantly improves the interface of the inorganic solid-state battery and significantly improves the high-temperature-resistant performance of the battery.

[0005] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of a high-temperature-resistant solid-state electrolyte film, the method comprising the following steps:

[0007] Step one, preparation of a meltable solid-state electrolyte: specifically, the following four parallel technical solutions are included: (1) uniformly mixing Li2S and AlCl3 at 200-300 DEG C and heating to obtain a sulfur-based meltable solid-state electrolyte matching a sulfide solid-state electrolyte; (2) uniformly mixing LiCl and AlCl3 at 200-300 DEG C and heating, then adding a metal oxide into the molten mixture to introduce oxygen elements, and removing impurities by vacuumizing at a high temperature of 250-350 DEG C to obtain an oxygen-based meltable solid-state electrolyte matching an oxide solid-state electrolyte; (3) uniformly mixing LiOH and a halide binary lithium salt, heating to 300-400 DEG C in a high-pressure reactor for 12-36 h, then slowly cooling to 200-300 DEG C for additional 12-36 h, and cooling to room temperature at a certain cooling rate to obtain a halogen-based meltable solid-state electrolyte matching a halide solid-state electrolyte; (4) mixing a halide binary lithium salt with GaF3 at a rotation speed of 500-800 rpm / min for 10-20 h to obtain a halogen-based meltable solid-state electrolyte matching a halide solid-state electrolyte;

[0008] Step two, ball-milling the meltable solid-state electrolyte of step one with a corresponding conventional solid-state electrolyte to obtain a composite solid-state electrolyte powder containing an inorganic binder;

[0009] Step three, uniformly filling the composite solid-state electrolyte powder in step two in a groove of 30-1000 μm, hot-pressing at a certain temperature and a pressure of 1-50 MPa for 2-30 min to obtain a high-temperature-resistant solid-state electrolyte film based on an inorganic binder.

[0010] Further, the method further comprises step four: to adapt to different positive and negative electrodes, selecting one or more of the oxide (matching lithium metal negative electrode), sulfide, halide (matching high-pressure oxide positive electrode) high-temperature-resistant solid-state electrolyte films obtained in step three to be alternately stacked, and hot-pressing in a groove at a certain temperature for 1-15 min (1-50 MPa) to obtain a multi-layer composite solid-state electrolyte film; the hot-pressing temperature of the multi-layer composite solid-state electrolyte film is the lowest hot-pressing temperature required by each layer, such as a sulfur-based and oxygen-based double-layer electrolyte film, and the hot-pressing temperature is 120-180 DEG C.

[0011] Further, in step one, the melting point of the fusible solid-state electrolyte is not higher than 300℃; the molar ratio of Li2S and AlCl3 is 0.5-3:1; the molar ratio of LiCl and AlCl3 is 0.5-3:1; the metal element in the metal oxide forms a compound with chlorine element that can volatilize below 350℃, such as one or more of Sb2O3, Fe2O3, HgO, Ga2O3, GeO2; the mass ratio of the molten mixture and the metal oxide is 1:0.1-0.5; the halide binary lithium salt is one or more of LiCl, LiBr, Lil, LiF, the molar ratio of LiOH and the halide binary lithium salt is 1:0.5-3; the cooling rate is 10-50℃ / h; the molar ratio of the halide binary lithium salt and GaF3 is 0.5-3:1.

[0012] Further, in step two, the conventional solid-state electrolyte is a sulfide, oxide, halide solid-state electrolyte, corresponding to a sulfur-based, oxygen-based, halogen-based fusible solid-state electrolyte, respectively; the molar ratio of the fusible solid-state electrolyte and the corresponding conventional solid-state electrolyte is 0.02-0.2:1.

[0013] Further, in step three, the hot-pressing temperature of the high-temperature-resistant solid-state electrolyte film is: the sulfur-based hot-pressing temperature is 120-180℃, the oxygen-based hot-pressing temperature is 150-200℃, and the halogen-based hot-pressing temperature is 60-300℃.

[0014] The application of a high-temperature-resistant solid-state electrolyte film prepared by the above method in an integrated solid-state battery, the application is:

[0015] Step 1: uniformly mix the alloyable anode powder and the thermally cyclizable polymer powder, add the mixed powder to a 2-4 times mass of N,N-dimethylformamide solution and stir for 6-24 h, then ultrasonic dispersion for 1-4 h, uniformly coat the obtained slurry on the surface of a copper current collector, dry the obtained electrode sheet in a 50-100℃ oven for 5-15 h, and heat treat the dried electrode sheet in an inert gas atmosphere at 250-500℃ for 1-5 h to obtain a high-temperature-resistant thermally cyclizable conductive layer coated carbon-free alloyable anode;

[0016] Step 2: uniformly mix the lithium-containing positive electrode material, the conventional solid-state electrolyte, the non-carbon conductive agent, and the fusible solid-state electrolyte according to a certain mass ratio to obtain a composite positive electrode powder; the conventional solid-state electrolyte and the fusible solid-state electrolyte in this step are the same as those in the preparation of the high-temperature-resistant solid-state electrolyte film;

[0017] Step 3: Put the high-temperature resistant thermal cyclization conductive layer coated carbon-free alloyable negative electrode obtained in step 1 at the bottom of a hot press tank, lay the fusible solid-state electrolyte (the same as step one of the preparation method of the high-temperature resistant solid-state electrolyte film) on the alloyable negative electrode, then put the high-temperature resistant solid-state electrolyte film on it, and finally uniformly lay the composite positive electrode powder obtained in step 2 on the surface of the high-temperature resistant solid-state electrolyte film, and then hot press at a certain temperature for 2-30 min (1-50 MPa), so that the fusible solid-state electrolyte of the positive electrode is melted and adhered to the solid-state electrolyte film, and a small amount of fusible solid-state electrolyte on the surface of the alloyable negative electrode penetrates into the alloy negative electrode under the action of hot pressing to create a continuous ion conduction path, and the negative electrode and the solid-state electrolyte film are adhered, and finally an integrated high-temperature resistant solid-state battery is obtained.

[0018] Further, in step 1, the alloyable negative electrode powder includes one or more of Si, Sn, Al, Mg, Ge, Zn which can form lithium alloy; the thermally cyclable polymer powder includes one or more of polyacrylonitrile, polyamide acid, polyimide; the mass ratio of the alloyable negative electrode powder to the thermally cyclable polymer powder is 1:0.05-0.3; the inert atmosphere is one or more of argon, nitrogen.

[0019] Further, in step 2, the lithium-containing positive electrode material is one or more of lithium iron phosphate, lithium cobaltate, lithium nickel-manganese cobaltate, lithium nickel-manganese aluminate, lithium manganate, lithium sulfide, lithium selenide; the non-carbon conductive agent is one or more of titanium sesquioxide, indium sesquioxide, titanium dioxide, polyaniline; the mass ratio is 90-30:10-60:5-15:2-8.

[0020] Further, in step 3, the ratio of the required mass of the composite positive electrode powder to the theoretical capacity of the negative electrode is 0.1-1:1; the hot pressing temperature is the highest temperature required for the melting of the fusible solid-state electrolyte on the surface of the negative electrode and the fusible solid-state electrolyte inside the positive electrode.

[0021] An integrated solid-state battery obtained by the above method, the solid-state battery comprising a high-temperature resistant solid-state electrolyte film and a molten and penetrated positive and negative electrode.

[0022] Compared with the prior art, the beneficial effects of the present application are:

[0023] (1) Unlike the traditional molten salt battery which can only operate at high temperature, the present application is based on inorganic solid-state electrolyte and fusible solid-state electrolyte which can conduct ions at low temperature, room temperature and high temperature, so that the operating temperature range of the obtained solid-state battery is wider and the working conditions are more suitable.

[0024] (2) The application uses inorganic fusible solid electrolyte to replace organic polymer as the binder of electrolyte film, and the prepared electrolyte film is more dense through melt infiltration, and the inorganic binder will not cause the high-temperature decomposition problem existing in the organic polymer binder at high temperature, so that the stability of the high-temperature battery is significantly improved. In addition, unlike other inorganic binders (such as silicate and phosphate), the fusible solid electrolyte used as the binder in the application has higher ionic conductivity, which is beneficial to the improvement of the battery performance, and at the same time, the use of water in the processing process of silicate and phosphate water-based binders is avoided, and the damage of water to the solid electrolyte is avoided.

[0025] (3) The application realizes the integrated preparation of the solid-state battery through the melt crosslinking of the positive and negative electrodes and the electrolyte, eliminates the large interface gap between the traditional electrodes, and develops the high-temperature solid-state battery without any conductive carbon, so that the reduction of the conductive carbon to the solid-state electrolyte at high temperature is avoided, and the stability of the high-temperature battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A comparison diagram of the high-temperature-resistant electrolyte film prepared by using the inorganic fusible binder and the electrolyte film prepared by using the organic binder;

[0027] Figure 2 A comparison diagram of the integrated solid-state battery and the non-integrated solid-state battery;

[0028] Figure 3 A cycle performance diagram of the integrated solid-state battery at 150 DEG C. DETAILED DESCRIPTION

[0029] The technical solutions in the application will be described clearly and completely in combination with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0030] The application uses the fusible solid electrolyte as the inorganic binder, avoids the decomposition of the traditional organic binder at high temperature and the use of destructive water in the bonding process, improves the electrolyte density and reliability. The application improves the battery interface contact through the batch production of the high-temperature-resistant solid-state electrolyte film and the integrated preparation of the battery, greatly improves the long-term cycle stability of the high-temperature battery, and expands the temperature range of the traditional high-temperature running battery to room temperature or even subzero range. The application will promote the progress of high-temperature batteries in special fields such as oil drilling, fire warning and commercial spaceflight.

[0031] Example 1:

[0032] (1) Li2S and AlCl3 were mixed and heated at 250 °C at a molar ratio of 1:1 to obtain a sulfur-based fusible solid-state electrolyte matching sulfide solid-state electrolyte; LiCl and GaF3 were mixed at a molar ratio of 1:1 at a rotation speed of 600 rpm / min for 12 h to prepare a halogen-based fusible solid-state electrolyte matching halide solid-state electrolyte;

[0033] (2) The sulfur-based fusible solid-state electrolyte of step (1) was ball-milled with Li6PS5Cl sulfide solid-state electrolyte at a molar ratio of 0.1:1, and the halogen-based fusible solid-state electrolyte of step (1) was ball-milled with Li3YCl6 halide solid-state electrolyte at a molar ratio of 0.1:1 to obtain sulfide and halide composite solid-state electrolyte powders containing inorganic binders, respectively;

[0034] (3) The sulfide composite solid-state electrolyte powder in step (2) was filled in a 50 μm groove and hot-pressed at 150 °C at a pressure of 10 MPa for 10 min to obtain a high-temperature-resistant sulfide solid-state electrolyte film based on inorganic binders; the halide composite solid-state electrolyte powder in step (2) was filled in a 50 μm groove and hot-pressed at 300 °C at a pressure of 10 MPa for 10 min to obtain a high-temperature-resistant halide solid-state electrolyte film based on inorganic binders; the obtained sulfide solid-state electrolyte film was placed at the bottom of a 100 μm hot-pressing groove, and the obtained halide solid-state electrolyte film was covered on top, and hot-pressed at 150 °C at a pressure of 5 MPa for 5 min to obtain a double-layer solid-state electrolyte film composed of sulfide and halide, wherein the sulfide side faces the negative electrode, and the halide side faces the positive electrode because the halide solid-state electrolyte is stable to high-voltage oxide positive electrode materials;

[0035] (4) Si powder and polyacrylonitrile powder were uniformly mixed at a mass ratio of 1:0.1, the mixed powder was added to a 3-fold mass of N,N-dimethylformamide solution and stirred for 12 h, followed by ultrasonic dispersion for 2 h, the obtained slurry was uniformly coated on the surface of a copper current collector, the obtained electrode sheet was dried in an oven at 60 °C for 10 h, and the dried electrode sheet was heat-treated at 270 °C for 3 h in an argon atmosphere to obtain a high-temperature-resistant heat-cyclized polyacrylonitrile-coated carbon-free Si negative electrode;

[0036] (5) NCM111, Li3YCl6, titanium sesquioxide, and the halogen-based fusible solid-state electrolyte in step (1) were uniformly mixed at a mass ratio of 60:20:15:5 to obtain a composite positive electrode powder;

[0037] (6) Put the high-temperature-resistant thermal cyclization polyacrylonitrile-coated carbon-free Si negative electrode obtained in step (4) at the bottom of a hot press tank, spread the sulfur-based fusible solid-state electrolyte in step (1) accounting for 5% of the mass of the negative electrode on the carbon-free Si negative electrode, then place the high-temperature-resistant double-layer solid-state electrolyte film obtained in step (3) thereon, and finally spread the composite positive electrode powder in step (5) required for a ratio of 0.8:1 of the theoretical capacity to the negative electrode theoretical capacity uniformly on the surface of the high-temperature-resistant solid-state electrolyte film, and then hot-press at 300°C for 10 min (5 MPa), so that the fusible solid-state electrolyte of the positive electrode melts and adheres to the solid-state electrolyte film, at the same time a small amount of sulfur-based fusible solid-state electrolyte on the surface of the carbon-free Si negative electrode penetrates into the Si negative electrode under the action of hot pressing to create a continuous ion conduction path, and the negative electrode and the solid-state electrolyte film are adhered, and finally an integrated high-temperature-resistant solid-state battery is obtained.

[0038] Example 2:

[0039] (1) Mix and heat Li2S and AlCl3 in a molar ratio of 1:1 at 250°C to obtain a sulfur-based fusible solid-state electrolyte matching the sulfide solid-state electrolyte;

[0040] (2) Ball-mill mix the sulfur-based fusible solid-state electrolyte in step (1) with Li6PS5Cl sulfide solid-state electrolyte in a molar ratio of 0.1:1 to obtain sulfide composite solid-state electrolyte powder containing an inorganic binder;

[0041] (3) Fill the sulfide composite solid-state electrolyte powder in step (2) into a 50 μm tank, and hot-press at 150°C under a pressure of 10 MPa for 10 min to obtain a high-temperature-resistant sulfide solid-state electrolyte film based on an inorganic binder;

[0042] (4) Uniformly mix Si powder and polyacrylonitrile powder in a mass ratio of 1:0.1, add the mixed powder into a solution of 3 times the mass of N,N-dimethylformamide, stir for 12 h, and then ultrasonic disperse for 2 h, uniformly coat the obtained slurry on the surface of a copper current collector, dry the obtained electrode sheet in an oven at 60°C for 10 h, and heat treat the dried electrode sheet at 270°C for 3 h in an argon atmosphere to obtain a high-temperature-resistant thermal cyclization polyacrylonitrile-coated carbon-free Si negative electrode;

[0043] (5) Uniformly mix a mixture of Li2S+FeS2 (mass ratio of 1:1), Li6PS5Cl, titanium sesquioxide, and the sulfur-based fusible solid-state electrolyte in step (1) in a mass ratio of 40:35:20:5 to obtain a composite positive electrode powder;

[0044] (6) Put the high-temperature-resistant thermal cyclization polyacrylonitrile-coated carbon-free Si negative electrode obtained in step (4) at the bottom of a hot press tank, evenly spread 5% of the sulfur-based fusible solid-state electrolyte in step (1) on the carbon-free Si negative electrode, then place the high-temperature-resistant solid-state electrolyte film obtained in step (3) thereon, and finally evenly spread the composite positive electrode powder of step (5) required in a ratio of 0.8:1 of the theoretical capacity to the negative electrode theoretical capacity on the surface of the high-temperature-resistant solid-state electrolyte film, and then hot-press at 150°C for 10 min (5 MPa), so that the fusible solid-state electrolyte of the positive electrode melts and adheres to the solid-state electrolyte film, and at the same time a small amount of sulfur-based fusible solid-state electrolyte on the surface of the negative electrode penetrates into the Si negative electrode under the action of hot pressing to create a continuous ion conduction path, and the negative electrode and the solid-state electrolyte film are adhered, and finally an integrated high-temperature-resistant solid-state battery is obtained.

[0045] Example 3:

[0046] (1) Mix LiCl and AlCl3 in a molar ratio of 1:1 at 280°C and heat, then add 10% by mass of Fe2O3 to the molten mixture to introduce oxygen elements, and remove impurities by vacuumizing at a high temperature of 300°C, to obtain an oxygen-based fusible solid-state electrolyte matching the oxide solid-state electrolyte;

[0047] (2) Ball-mill mix the oxygen-based fusible solid-state electrolyte of step (1) with the LLZTO oxide solid-state electrolyte in a molar ratio of 0.1:1 to obtain an oxide composite solid-state electrolyte powder containing an inorganic binder;

[0048] (3) Fill the oxide composite solid-state electrolyte powder in step (2) in a 50 μm tank, and hot-press at a pressure of 10 MPa at 180°C for 10 min to obtain a high-temperature-resistant oxide solid-state electrolyte film based on an inorganic binder;

[0049] (4) Uniformly mix Si powder and polyacrylonitrile powder in a mass ratio of 1:0.1, add the mixed powder to a solution of 3 times the mass of N,N-dimethylformamide, stir for 12 h, and then ultrasonic disperse for 2 h, evenly coat the obtained slurry on the surface of a copper current collector, dry the obtained electrode sheet in an oven at 60°C for 10 h, and heat treat the dried electrode sheet at 270°C for 3 h in an argon atmosphere to obtain a high-temperature-resistant thermal cyclization polyacrylonitrile-coated carbon-free Si negative electrode;

[0050] (5) Uniformly mix NCM111, LLZTO, titanium sesquioxide, and the oxygen-based fusible solid-state electrolyte in step (1) in a mass ratio of 60:20:15:5 to obtain a composite positive electrode powder;

[0051] (6) Put the high-temperature-resistant thermal cyclization polyacrylonitrile-coated carbon-free Si negative electrode obtained in step (4) at the bottom of a hot press tank, spread 5% of the oxygen-based fusible solid-state electrolyte in step (1) on the carbon-free Si negative electrode by mass, then put the high-temperature-resistant oxide solid-state electrolyte film obtained in step (3) on it, and finally spread the composite positive electrode powder required for a ratio of 0.8:1 of the theoretical capacity to the negative electrode theoretical capacity in step (5) on the surface of the high-temperature-resistant solid-state electrolyte film, and then hot-press at 180°C for 10 min (5 MPa), so that the fusible solid-state electrolyte of the positive electrode melts and adheres to the solid-state electrolyte film, at the same time, a small amount of oxygen-based fusible solid-state electrolyte on the surface of the carbon-free Si negative electrode penetrates into the Si negative electrode under the action of hot pressing to create a continuous ion conduction path, and the negative electrode and the solid-state electrolyte film are adhered, and finally an integrated high-temperature-resistant solid-state battery is obtained.

[0052] Comparative Example 1:

[0053] The difference between this comparative example and Example 1 is that the operation of adding halogen-based fusible solid-state electrolyte in the composite positive electrode powder in step (5) is not performed, and the operation of spreading sulfur-based fusible solid-state electrolyte on the carbon-free Si negative electrode in step (6) is not performed, and the rest of the conditions and parameters are exactly the same as Example 1.

[0054] Comparative Example 2:

[0055] The difference between this comparative example and Example 2 is that the operation of adding sulfur-based fusible solid-state electrolyte in the composite positive electrode powder in step (5) is not performed, and the operation of spreading sulfur-based fusible solid-state electrolyte on the carbon-free Si negative electrode in step (6) is not performed, and the rest of the conditions and parameters are exactly the same as Example 2.

[0056] Comparative Example 3:

[0057] The difference between this comparative example and Example 3 is that the operation of adding oxygen-based fusible solid-state electrolyte in the composite positive electrode powder in step (5) is not performed, and the operation of spreading oxygen-based fusible solid-state electrolyte on the carbon-free Si negative electrode in step (6) is not performed, and the rest of the conditions and parameters are exactly the same as Example 3.

[0058] The present application uses fusible solid-state electrolyte as a binder to bond traditional inorganic solid-state electrolyte, avoiding the challenge of high-temperature decomposition of traditional organic binders, while enhancing the density of the electrolyte. Combined with the preparation of integrated solid-state batteries, the interface contact between the electrodes is optimized, avoiding the use of conductive carbon in the battery which is detrimental to the solid-state electrolyte, significantly improving the cycle capacity of the battery at high temperature. Importantly, using fusible solid-state electrolyte as a binder also widens the use temperature of high-temperature-resistant batteries, making up for the disadvantage of traditional molten salt high-temperature-resistant batteries that can only be used at high temperature, so that the developed high-temperature batteries can also operate at room temperature or even subzero temperature. For example,Figure 1 As shown in the schematic diagram, the electrolyte film using the fusible solid electrolyte as the binder has better compactness and is more resistant to decomposition at high temperatures. As shown in the schematic diagram, Figure 2 the interface contact between the electrodes of the integrated solid-state battery is good, the internal pores of the electrodes are few, and there is no carbon component that is not conducive to high temperature. As shown in the schematic diagram, Figure 3 As shown in the schematic diagram, the integrated high-temperature batteries assembled in Examples 1-3 have better cycle performance than Comparative Examples 1-3 at 150°C.

[0059] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. The skilled person should consider the specification as a whole, and the technical solutions in each example can be appropriately combined to form other embodiments that can be understood by the skilled person.

Claims

1. A method for preparing a high-temperature resistant solid electrolyte membrane, characterized in that: The method comprises the following steps: Step 1. Preparation of fusible solid electrolyte: Specifically, it includes the following four parallel technical schemes: (1) Mix Li2S and AlCl3 at 200~300℃ and heat them to obtain a sulfur-based fusible solid electrolyte matching the sulfide solid electrolyte; (2) Mix LiCl and AlCl3 at 200~300℃ and heat them, then add metal oxide to the molten mixture to introduce oxygen elements, and remove impurities by high-temperature vacuum at 250~350℃ to obtain an oxygen-based fusible solid electrolyte matching the oxide solid electrolyte; (3) Mix LiOH and halide binary lithium salt evenly, heat them to 300~400℃ in a high-pressure reactor and keep them for 12~36 hours, then slowly cool them to 200~300℃ and keep them for another 12~36 hours, and then cool them to room temperature at a certain cooling rate to obtain a halogen-based fusible solid electrolyte matching the halide solid electrolyte; (4) Mix halide binary lithium salt with GaF3 at 500~800℃ rmp / min for 10-20 h to obtain a halogen-based fusible solid electrolyte that matches the halide solid electrolyte; Step 2: The four fusible solid electrolytes obtained in step 1 are respectively mixed with corresponding conventional solid electrolytes by ball milling to obtain four composite solid electrolyte powders containing an inorganic binder; Step 3: The four composite solid electrolyte powders containing inorganic binders obtained in step 2 are uniformly filled in grooves of 30 to 1000 μm, and hot pressed at a certain temperature and a pressure of 1 to 50 MPa for 2 to 30 min to obtain four high-temperature resistant solid electrolyte membranes based on inorganic binders.

2. The method for preparing a high-temperature resistant solid electrolyte membrane according to claim 1, wherein: The method also includes a fourth step: to adapt to different positive and negative electrodes, one or more of the four high-temperature resistant solid electrolyte membranes based on inorganic binders obtained in step three are selected for alternate stacking, and hot pressing is performed in a tank at a certain temperature for 1 to 15 minutes, with a hot pressing pressure of 1 to 50 MPa, to obtain a multilayer composite solid electrolyte membrane; the hot pressing temperature of the multilayer composite solid electrolyte membrane is the minimum hot pressing temperature required for each layer.

3. The method for preparing a high temperature resistant solid electrolyte membrane according to claim 1 or 2, characterized in that: In step 1, the melting point of the fusible solid electrolyte is not higher than 300°C; the molar ratio of Li2S and AlCl3 is 0.5~3:1; the molar ratio of LiCl and AlCl3 is 0.5~3:1; the metal oxide is one or more of Sb2O3, Fe2O3, HgO, Ga2O3, GeO2; the mass ratio of the molten mixture to the metal oxide is 1:0.1~0.5; the halide binary lithium salt is one or more of LiCl, LiBr, LiI, LiF, and the molar ratio of LiOH to the halide binary lithium salt is 1:0.5~3; the cooling rate is 10~50°C / h; the molar ratio of the halide binary lithium salt to GaF3 is 0.5~3:

1.

4. The method for preparing a high temperature resistant solid electrolyte membrane according to claim 1 or 2, characterized in that: In step 2, the traditional solid electrolyte is a sulfide, oxide, or halide solid electrolyte, corresponding to sulfur-based, oxygen-based, and halogen-based fusible solid electrolytes, respectively; the molar ratio of the fusible solid electrolyte to the corresponding traditional solid electrolyte is 0.02~0.2:

1.

5. The method for preparing a high temperature resistant solid electrolyte membrane according to claim 1 or 2, characterized in that: In step 3, the hot pressing temperature of the high temperature resistant solid electrolyte membrane is: 120-180°C for sulfur series, 150-200°C for oxygen series, and 60-300°C for halogen series.

6. Use of a high-temperature resistant solid electrolyte membrane prepared by the method according to any one of claims 1 to 5 in an integrated solid-state battery, characterized in that: The applications are: Step 1: The alloyable negative electrode powder and the heat-cyclizable polymer powder are uniformly mixed, the mixed powder is added to 2-4 times the mass of N, N-dimethylformamide solution and stirred for 6-24 hours, followed by ultrasonic dispersion for 1-4 hours, and the resulting slurry is evenly coated on the surface of the copper current collector. The obtained electrode is dried in an oven at 50-100°C for 5-15 hours, and the dried electrode is heat-treated at 250-500°C for 1-5 hours under an inert gas atmosphere to obtain a carbon-free alloyable negative electrode coated with a high-temperature resistant heat-cyclized conductive layer; Step 2: uniformly mixing the lithium-containing positive electrode material, the traditional solid electrolyte, the non-carbon conductive agent and the fusible solid electrolyte in a certain mass ratio to obtain a composite positive electrode powder; Step 3: Place the carbon-free alloyable negative electrode coated with the high-temperature resistant heat-cyclized conductive layer obtained in step 1 at the bottom of the hot pressing tank, and spread a fusible solid electrolyte accounting for 1~10% of the mass of the negative electrode on the alloyable negative electrode, and then place the high-temperature resistant solid electrolyte membrane on it. Finally, the composite positive electrode powder obtained in step 2 is evenly spread on the surface of the high-temperature resistant solid electrolyte membrane, and then hot-pressed at a certain temperature for 2~30 min, and the hot pressing pressure is 1~50 MPa to obtain an integrated high-temperature resistant solid-state battery.

7. Use of the high-temperature resistant solid electrolyte membrane according to claim 6 in an integrated solid-state battery, characterized in that: In step 1, the alloyable negative electrode powder includes one or more of Si, Sn, Al, Mg, Ge, and Zn; the thermally cyclizable polymer powder includes one or more of polyacrylonitrile, polyamic acid, and polyimide; the mass ratio of the alloyable negative electrode powder to the thermally cyclizable polymer powder is 1:0.05~0.3; and the inert gas is one or more of argon and nitrogen.

8. The use of the high temperature resistant solid electrolyte membrane in an integrated solid-state battery according to claim 6, characterized in that: In step 2, the lithium-containing positive electrode material is one or more of lithium iron phosphate, lithium cobaltate, lithium nickel manganese cobaltate, lithium nickel manganese aluminum oxide, lithium manganese oxide, lithium sulfide, and lithium selenide; the non-carbon conductive agent is one or more of titanium oxide, indium oxide, titanium dioxide, and polyaniline; and the mass ratio is 90~30:10~60:5~15:2~8.

9. The use of the high temperature resistant solid electrolyte membrane in an integrated solid-state battery according to claim 6, characterized in that: In step 3, the ratio of the theoretical capacity corresponding to the required mass of the composite positive electrode powder to the theoretical capacity of the negative electrode is 0.1~1:1; the hot pressing temperature is the maximum temperature required for the melting of the fusible solid electrolyte on the surface of the negative electrode and the fusible solid electrolyte inside the positive electrode.

10. An integrated solid-state battery according to any one of claims 6 to 9, characterized in that: The solid-state battery includes a high-temperature resistant solid electrolyte membrane and a melt-penetrated positive and negative electrode.

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