CN118336091A - A spliced solid electrolyte based on inorganic solder and preparation method thereof - Google Patents

Abstract

A spliced solid electrolyte based on inorganic solder and a preparation method thereof, which is a large-size solid electrolyte for lithium-ion batteries, sodium-ion batteries, medium- and high-temperature fuel cells, etc., including electrolytes of various shapes that are easy to form and sinter, which are welded together in the required shape by inorganic solder. The preparation method has the advantages of low technical difficulty, high production efficiency, and low equipment cost.

Description

A spliced solid electrolyte based on inorganic solder and preparation method thereof

Technical Field

The present invention relates to the technical field of solid electrolytes, and in particular, to a spliced solid electrolyte based on inorganic solder and a preparation method thereof.

Background technique

Solid electrolytes include lithium-ion solid electrolytes, sodium-ion solid electrolytes and oxygen-ion solid electrolytes. Lithium-ion solid electrolytes are important materials for solid-state lithium batteries and molten lithium metal batteries, while sodium-ion solid electrolytes and oxygen-ion solid electrolytes are important materials for molten sodium metal batteries and medium- and high-temperature fuel cells. The performance of solid electrolytes has an important influence on the performance of the corresponding batteries. The following is an important explanation using lithium-ion ceramic electrolytes as an example.

Molten lithium metal batteries based on lithium-ion ceramic electrolytes have the advantages of high safety, high energy density, high coulombic efficiency and low cost, and are expected to be used in large-scale grid energy storage and power batteries.

CN201980029459.5 discloses a molten lithium electrochemical cell based on a solid electrolyte, comprising: an anode, wherein the anode comprises lithium metal or a lithium alloy; a cathode separated from the anode, wherein the cathode comprises a cathode material that reacts with the anode; and a solid electrolyte located between the anode and the cathode, wherein the solid electrolyte comprises a lithium ion conductive oxide, a lithium ion conductive phosphate, a lithium ion conductive sulfide, or any combination of the foregoing.

CN201980092766.8 discloses a high energy density molten lithium sulfur and lithium selenium battery with a solid electrolyte, comprising: an anode comprising lithium metal or a lithium alloy; a cathode comprising sulfur, selenium or a mixture thereof; and a solid electrolyte located between the anode and the cathode, wherein the solid electrolyte is capable of conducting lithium ions.

In addition, the lithium extraction method based on lithium-ion ceramic electrolyte can produce high-purity lithium products from low-purity lithium salt raw materials, which has the advantages of low cost, high efficiency and environmental protection.

CN201910377098.5 discloses a method for preparing metallic lithium based on a solid electrolyte, wherein a mixture containing lithium metal is used as an anode, a solid electrolyte containing lithium ions is used as an electrolyte, and an electrolysis reaction is carried out in an electrolysis device to obtain metallic lithium at the cathode.

CN110106369A discloses a method and device for extracting lithium based on lithium ion solid electrolyte, wherein the method comprises the following steps: inserting a metal material participating in the reaction into an anode containing a lithium salt solution to obtain an active electrode of an anode current collector; inserting an inert material into a cathode containing a lithium chloride aqueous solution to obtain an inert electrode of a cathode current collector; isolating the anode current collector from the cathode current collector, and under the drive of an electric field, migrating lithium ions in a lithium salt liquid from the anode to the cathode through a lithium ion solid electrolyte or a mixture containing a lithium ion solid electrolyte, and extracting lithium at the inert electrode.

The above-mentioned molten lithium metal battery and lithium element extraction involve a lithium ion ceramic electrolyte tube with one end sealed. The lithium ion ceramic electrolyte tube known to the inventor is generally "U"-shaped, and its traditional preparation process is to first press the ceramic powder into a "U"-shaped tube green body, and then sinter it at high temperature into a ceramic tube.

CN202210022945.8 discloses a high-temperature molten lithium-iodine battery based on garnet solid electrolyte, comprising a garnet solid electrolyte, a positive electrode material and a negative electrode material; the garnet solid electrolyte is LLZTO ceramic, the positive electrode material comprises CsI/LiI eutectic salt, the negative electrode material is molten metallic lithium, and the garnet solid electrolyte is a U-shaped ceramic tube.

CN201210537640.7 discloses a sodium-sulfur battery, comprising a ceramic electrolyte tube and a sodium storage tube sleeved inside the ceramic electrolyte tube, wherein the ceramic electrolyte tube is a U-shaped ceramic tube.

For electrolyte ceramic tubes, the traditional preparation process has disadvantages such as high technical difficulty, high equipment cost, and low production efficiency. It is difficult to achieve mass production of large-sized ceramic tubes, and the resulting ceramic tubes have poor performance.

CN202010877519.3 discloses a co-sintered modified solid electrolyte ceramic sheet, which is obtained by co-sintering lithium aluminum titanium phosphate (LATP), boric acid (HBO ₃ ), and yttrium oxide (Y ₂ O ₃ ) and/or zirconium oxide (ZrO ₂ ), wherein lithium aluminum titanium phosphate is the matrix, the mass percentage of boric acid in the matrix is 2-10%wt, and the mass percentage of yttrium oxide and/or zirconium oxide in the matrix is 1-5%wt.

CN202010764761.X discloses a polymer in-situ modified inorganic solid electrolyte ceramic sheet. One side of the inorganic solid electrolyte ceramic sheet uses a polymer modification layer containing lithium salt as the negative electrode side, and the other opposite side is modified with polyvinyl carbonate (PVCA) containing lithium salt and plasticizer in situ polymerized by vinyl carbonate (VC) as the positive electrode side. The final structure is a polymer-inorganic ceramic sheet-polymer sandwich solid electrolyte structure.

CN200680027247.6 discloses a method for manufacturing a solid electrolyte sheet for a solid oxide fuel cell, comprising the following steps: a step of obtaining a thin large piece of zirconium oxide embryo sheet by molding and drying a slurry containing zirconium oxide particles, a binder, a plasticizer and a dispersion medium; a step of pressurizing the zirconium oxide embryo sheet at a pressure greater than or equal to 10 MPa and less than or equal to 40 MPa in the thickness direction; a step of calcining the pressurized zirconium oxide embryo sheet at 1200-1500°C; and a step of controlling the time in the temperature range from 500°C to 200°C to be greater than 100 minutes and less than 400 minutes during cooling after calcination.

CN201811551788.X discloses a method for preparing an oxide solid electrolyte sheet, which is characterized by comprising the following steps:

(1) Preparing powder: drying or roasting, grinding and mixing the oxide solid electrolyte powder uniformly;

(2) Airflow-assisted powder covering: The powder reaches the tablet pressing die through a vertical material guide pipe. The upper end of the material guide pipe is a wire mesh. The powder is passed through the wire mesh into the material guide pipe by a scraper. The tablet pressing die is placed at the bottom of the material guide pipe. At the same time, airflow is introduced into the upper area of the material guide pipe below the wire mesh. The air field is regulated to make the powder evenly distributed, and the powder falls evenly and covers the tablet pressing die by gravity.

(3) Tablet pressing: clean the powder covering the periphery of the tablet pressing mold and press the powder in the tablet pressing mold into a sample green tablet;

(4) High temperature sintering: Place the sample green sheet between two sintering plates and sinter in a high temperature furnace. The sintering temperature range is 300℃-1800℃.

CN202211091092.X discloses a composite solid electrolyte membrane, characterized in that the composite solid electrolyte membrane comprises:

A porous solid electrolyte membrane and nano-silicon; wherein the composite solid electrolyte membrane uses the porous solid electrolyte membrane as a skeleton, and deposits silicon after gas decomposition of a silicon source material into the pores of the porous solid electrolyte membrane by a vapor deposition method to form nuclei and grow nano-silicon; the content of the nano-silicon decreases in the thickness direction from the first surface to the second surface of the composite solid electrolyte membrane; the mass of the nano-silicon accounts for 20%-90% of the mass of the porous solid electrolyte membrane.

The prior art rarely involves the preparation of large-sized solid electrolyte ceramic sheets or solid electrolyte structures of other shapes. The preparation of large-sized solid electrolyte ceramic sheets or solid electrolyte structures of other shapes known to the inventors also has problems such as high equipment cost, low preparation process efficiency, low yield, and poor stability of the obtained products.

Summary of the invention

The purpose of the present invention is to overcome the defects of the prior art and provide a spliced solid electrolyte based on inorganic solder and a preparation method thereof, so as to realize high-quality and high-efficiency production of large-size solid electrolytes, wherein the large-size solid electrolyte includes but is not limited to a solid electrolyte tubular structure with an inner diameter ≥3mm and a depth ≥2mm, and a solid electrolyte sheet structure or a solid electrolyte block structure with an area ^≥1cm2 , or a solid electrolyte tubular structure with an inner diameter ≥5mm and a depth ≥3mm, and a solid electrolyte sheet structure or a solid electrolyte block structure with an area ^≥3cm2 , or a solid electrolyte tubular structure with an inner diameter ≥7mm and a depth ≥3mm, and a solid electrolyte sheet structure or a solid electrolyte block structure with an area ≥5cm2, or a solid electrolyte tubular structure with an inner diameter ≥7mm and a depth ≥3mm, and a solid electrolyte sheet structure or a solid electrolyte block structure with an area ^≥5cm2 .

The solid electrolyte materials of the present invention include but are not limited to ceramics and glass, and the prepared solid electrolyte has excellent air tightness and chemical stability. The prepared solid electrolyte does not chemically react with molten metal lithium and molten salt. The leakage rate of the prepared solid electrolyte does not change substantially after being corroded by molten metal lithium and molten salt.

The present invention first provides a spliced solid electrolyte based on inorganic solder, which is a large-size solid electrolyte for lithium-ion batteries, sodium-ion batteries, medium- and high-temperature fuel cells, etc., including electrolytes of various shapes that are easy to form and sinter, and are welded together in the desired shape by inorganic solder.

Furthermore, the large-sized solid electrolyte includes but is not limited to a solid electrolyte tubular structure, a solid electrolyte sheet structure or a solid electrolyte block structure.

Furthermore, the electrolyte material includes but is not limited to ceramics, glass, etc.

Furthermore, the inorganic solder includes but is not limited to a mixture of alkali metal compounds and Al ₂ O ₃ , inorganic salts, etc.; the alkali metal compound is a mixture of one or more (two or three) of Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ , KOH, wherein the molar ratio of the alkali metal element to the Al element in the mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc.

Furthermore, the large-size solid electrolyte is a solid electrolyte tubular structure, and the solid electrolyte tubular structure is a lithium-ion ceramic electrolyte tube and a sodium-ion ceramic electrolyte tube, including a lithium-ion ceramic electrolyte tubular portion, a sodium-ion ceramic electrolyte tubular portion, and a ceramic bottom seal, wherein the lithium-ion ceramic electrolyte tubular portion, the sodium-ion ceramic electrolyte tubular portion and the ceramic bottom seal are welded together by inorganic solder.

Furthermore, the material of the tubular portion of the lithium-ion ceramic electrolyte includes but is not limited to lithium lanthanum zirconate (LLZO), lithium aluminum titanium phosphate (LATP), lithium lanthanum titanate (LLTO), and the like.

Furthermore, the material of the tubular portion of the sodium ion ceramic electrolyte includes Na-β″-Al ₂ O ₃ sodium ion solid electrolyte, NASICON type, sulfide and borohydride, etc.

Furthermore, at least one end of the ceramic electrolyte tube is sealed.

Furthermore, the inner diameter of the ceramic electrolyte tube is ≥3 mm and the depth is ≥2 mm.

Furthermore, the ceramic electrolyte tubular portion and the ceramic bottom seal are made of the same or different materials.

Furthermore, the cross-sectional shape of the ceramic electrolyte tubular portion includes but is not limited to circular, hexagonal, rectangular, triangular, and four-leaf clover shapes.

Furthermore, the large-size solid electrolyte is a solid electrolyte sheet structure or a solid electrolyte block structure, etc.

Furthermore, the solid electrolyte sheet structure is circular, square, rectangular, triangular, trapezoidal, irregular, etc.

Furthermore, the electrolyte tube or electrolyte sheet is placed on a helium mass spectrometer leak detector for airtightness test, and its helium leakage rate is not higher than 1×10 ^-8 Pa·m ³ /s, or not higher than 1×10 ^-9 Pa·m ³ /s, or not higher than 1×10 ^-10 Pa·m ³ /s, indicating good airtightness.

Furthermore, the electrolyte tube or electrolyte sheet is placed in molten lithium metal and kept at 200-400° C. for more than 200 hours or more than 300 hours. After the end, no obvious reaction phenomenon is found at the weld, that is, the inorganic solder is chemically stable to lithium metal.

Furthermore, the electrolyte tube or electrolyte sheet is tested for corrosion resistance of the weld to MCl molten salt (M is an alkali metal) by placing it in a mixed molten salt of KCl and NaCl and keeping it at 400°C for 240h or 280h; after the test, the surface molten salt is cleaned and dried, and it is found that the color of the weld has no obvious change, and the air tightness test shows that the helium leakage rate is not higher than 1× ^10-8 Pa· ^m3 /s, or not higher than 1× ^10-9 Pa· ^m3 /s, or not higher than 1× ^10-10 Pa· ^m3 /s, and the air tightness is good. Therefore, it can be judged that the inorganic solder does not undergo chemical corrosion, that is, the inorganic solder is stable to MCl molten salt.

Furthermore, the electrolyte tube or electrolyte sheet is verified by the corrosion resistance of the weld to MCr molten salt (M is an alkali metal), and is placed in a mixed molten salt of KBr and NaBr, and lithium metal is added to the upper layer of the molten salt to form a lithium-saturated molten salt, and is kept at 400°C for 200h or 300h; after the end, the lithium metal and molten salt on the surface are cleaned and dried, and it is found that there is no obvious change in the color of the weld, and the air tightness test shows that the helium leakage rate is not higher than 1× ^10-8 Pa· ^m3 /s, or not higher than 1× ^10-9 Pa· ^m3 /s, or not higher than 1× ^10-10 Pa· ^m3 /s, and the air tightness is good. Therefore ^, it can be judged that the inorganic solder does not undergo chemical corrosion, that is, the inorganic solder is stable to the lithium-saturated MCr molten salt.

Furthermore, the electrolyte tube or electrolyte sheet is verified by the weld corrosion resistance of lithium-saturated MCl molten salt. The electrolyte after welding is placed in a mixed molten salt of KCl and NaCl, and lithium metal is added to the upper layer of the molten salt to form a lithium-saturated molten salt, which is kept at 400°C for 200 hours. After the completion, the lithium metal and molten salt on the surface are cleaned and dried, and it is found that the color of the weld has no obvious change. The airtightness test shows that the helium leakage rate is not higher than 1× ^10-8 Pa· ^m3 /s, or not higher than 1× ^10-9 Pa· ^m3 /s, or not higher than 1× ^10-10 Pa· ^m3 /s, and the airtightness is good. Therefore, it can be judged that the inorganic solder does not undergo chemical corrosion, that is, the inorganic solder is stable to lithium-saturated MCl molten salt.

Furthermore, the electrolyte tube or electrolyte sheet is verified by the weld corrosion resistance of lithium-saturated MCr molten salt. The electrolyte after welding is placed in a mixed molten salt of KBr and NaBr, and lithium metal is added to the upper layer of the molten salt to form a lithium-saturated molten salt, which is kept at 400°C for 300 hours. After the completion, the lithium metal and molten salt on the surface are cleaned and dried, and it is found that there is no obvious change in the color of the weld. The airtightness test shows that the helium leakage rate is not higher than 1× ^10-8 Pa· ^m3 /s, or not higher than 1× ^10-9 Pa· ^m3 /s, or not higher than 1× ^10-10 Pa· ^m3 /s, and the airtightness is good. Therefore, it can be judged that the inorganic solder does not undergo chemical corrosion, that is, the inorganic solder is stable to lithium-saturated MCr molten salt.

The present invention also provides an inorganic solder for preparing a spliced solid electrolyte, the inorganic solder including but not limited to a mixture of an alkali metal compound and Al ₂ O ₃ , an inorganic salt, etc., the alkali metal compound is a mixture of one or more (two or three) of Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ , KOH, wherein the molar ratio of the alkali metal element to the Al element in the mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt includes but not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc.

Furthermore, the alkali metal compound is one, two or a mixture of three of Li ₂ CO ₃ , Li ₂ O and LiOH.

Furthermore, the alkali metal compound is one of Na ₂ CO ₃ and NaOH, or a mixture of the two.

Furthermore, the alkali metal compound is one of K ₂ CO ₃ and KOH, or a mixture of the two.

The present invention also provides a method for preparing a spliced solid electrolyte based on inorganic solder, wherein the solid electrolyte includes but is not limited to ceramic and glass lithium ion solid electrolytes, sodium ion solid electrolytes and oxygen ion solid electrolytes, etc., and is spliced using inorganic solder, and the preparation steps include:

For the solid electrolyte tubular structure: firstly prepare a solid electrolyte straight tube or curved tube with two ends open and easy to form and sinter, whose cross-sectional shapes include but are not limited to circular, hexagonal, rectangular, triangular and four-leaf clover shapes, and a solid electrolyte sheet structure including but not limited to circular for bottom sealing, and then weld the two together with inorganic solder to form a solid electrolyte tubular structure with one end sealed;

For solid electrolyte sheet structures or block structures: first prepare a solid electrolyte sheet or block structure that is easy to form and sinter, the shape includes but is not limited to triangle, rectangle, hexagon, irregular shape, etc., and then use inorganic solder to weld the solid electrolyte sheet or block structure together to form a larger size solid electrolyte sheet or solid electrolyte block.

Furthermore, the solid electrolyte includes but is not limited to ceramic and glass lithium ion solid electrolytes, sodium ion solid electrolytes and oxygen ion solid electrolytes, for example, it can be lanthanum zirconate lithium ceramic electrolyte, _Li2S - _SiS2 glass solid electrolyte, Na-β″ _{-Al2O3 sodium} ion solid electrolyte and ZrO2 _- based oxygen ion solid electrolyte, etc.

Furthermore, for the solid electrolyte tubular structure, the ceramic electrolyte tube includes a ceramic electrolyte straight tube or curved tube with both ends open, which is easy to form and sinter, and its cross-sectional shape includes but is not limited to circular, hexagonal, rectangular, triangular and four-leaf clover shapes, etc., and a ceramic sheet including but not limited to circular for the bottom sealing; inorganic solder.

Further, for the solid electrolyte tubular structure, the ceramic electrolyte tube includes a ceramic electrolyte tubular portion and a ceramic bottom seal, wherein the ceramic electrolyte tubular portion and the ceramic bottom seal are welded together by an inorganic solder, including:

(1) According to the required structure, select the ceramic electrolyte tubular structure and ceramic bottom cover of appropriate size and wait for welding.

(2) weighing Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ or KOH and Al ₂ O ₃ , or weighing an inorganic salt, wherein the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc., at a molar ratio of alkali metal elements to Al elements of 1:5 to 10:1;

The weighed material is ball-milled at a speed of 200 to 400 r/min for 8 to 20 hours to obtain a uniformly mixed inorganic solder powder.

(3) Pressing the inorganic solder in step (2) into a shape according to factors such as the shape of the weld and the thickness of the electrolyte,

(4) placing the ceramic electrolyte tubular structure in step (1), the ceramic bottom seal and the inorganic solder in step (3) according to the required structure, and then sintering at 900 to 1200° C. for 10 to 120 min to obtain a ceramic electrolyte tube;

Alternatively, the ceramic electrolyte tubular structure in step (1), the ceramic bottom seal and the inorganic solder in step (3) are arranged in a desired structure, and then kept at 400 to 600° C. for 30 to 220 minutes to obtain a ceramic electrolyte tube.

Furthermore, the solid electrolyte sheet structure includes:

(1) According to the required structure, select the ceramic electrolyte sheet structure with appropriate size and wait for welding.

(2) weighing Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ or KOH and Al ₂ O ₃ , or weighing an inorganic salt, wherein the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc., at a molar ratio of alkali metal elements to Al elements of 1:5 to 10:1;

The weighed material is ball-milled at a speed of 200 to 400 r/min for 8 to 20 hours to obtain a uniformly mixed inorganic solder powder.

(3) splicing the ceramic electrolyte sheet structure in step (1) into a structure of a desired shape, placing the inorganic solder in step (2) according to the desired structure, and then sintering at 900 to 1200° C. for 10 to 120 min to obtain a ceramic electrolyte sheet;

Alternatively, the ceramic electrolyte sheet structure in step (1) is spliced into a structure of a desired shape, the inorganic solder in step (2) is placed according to the desired structure, and then kept at 400-650° C. for 30-220 minutes to obtain a ceramic electrolyte sheet.

Furthermore, the ceramic electrolyte is a lithium ion ceramic electrolyte or a sodium ion ceramic electrolyte.

Furthermore, the lithium ion ceramic electrolyte material of the ceramic electrolyte tubular portion includes but is not limited to lithium lanthanum zirconate (LLZO), lithium aluminum titanium phosphate (LATP), lithium lanthanum titanate (LLTO), and the like.

Furthermore, one end of the ceramic electrolyte tube is sealed.

Furthermore, the inner diameter of the ceramic electrolyte tube is ≥3 mm and the depth is ≥2 mm.

Furthermore, the wall thickness of the ceramic electrolyte tube is ≥0.1 mm.

Furthermore, the ceramic electrolyte tubular portion and the ceramic bottom seal are made of the same or different materials.

Furthermore, the cross-sectional shape of the ceramic electrolyte tubular portion includes but is not limited to circular, hexagonal, rectangular, triangular, and four-leaf clover shapes.

Further, the inorganic solder is a mixture of Li ₂ CO ₃ and Al ₂ O ₃ , or a mixture of Li ₂ O and Al ₂ O ₃ , or a mixture of LiOH and Al ₂ O ₃ , or a mixture of Na ₂ CO ₃ and Al ₂ O ₃ , or a mixture of NaOH and Al ₂ O ₃ , or a mixture of K ₂ CO ₃ and Al ₂ O ₃ , or a mixture of KOH and Al ₂ O ₃ , wherein the molar ratio of the alkali metal element to the Al element in each mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; too high or too low a molar ratio will increase its welding temperature.

Furthermore, the inorganic solder is a mixture of one or more of halogen salts, carbonates, sulfates, etc.

Furthermore, the welding temperature is 900-1200° C., preferably 1000-1100° C.; the welding time is 10-120 min, preferably 10-30 min.

Furthermore, the insulation temperature is 450-600° C., preferably 500-550° C.; the welding time is 40-200 min, preferably 90-120 min.

The present invention also provides a use of an inorganic solder in preparing a spliced solid electrolyte, wherein the solid electrolyte is a large-size solid electrolyte used for lithium ion batteries, sodium ion batteries, medium and high temperature fuel cells, etc. The inorganic solder includes but is not limited to a mixture of an alkali metal compound and _Al2O3 , an _inorganic salt, etc. The alkali metal compound is a mixture of one or more (two or three) of _Li2CO3 , _Li2O , _{LiOH, Na2CO3 ,} NaOH, _K2CO3 , _and KOH, wherein _the molar ratio of the alkali metal element to the Al element in the mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc.; wherein the inorganic solder is used as a solder between the tubular part of the electrolyte tubular structure and the ceramic bottom seal, or the inorganic solder is used as a solder between the electrolyte sheet structures.

Furthermore, the large-size solid electrolyte is a solid electrolyte tubular structure, and the solid electrolyte tubular structure is a lithium-ion ceramic electrolyte tube and a sodium-ion ceramic electrolyte tube, including a lithium-ion ceramic electrolyte tubular portion, a sodium-ion ceramic electrolyte tubular portion, and a ceramic bottom seal, wherein the lithium-ion ceramic electrolyte tubular portion, the sodium-ion ceramic electrolyte tubular portion and the ceramic bottom seal are welded together by inorganic solder.

Further, the inorganic solder is a mixture of Li ₂ CO ₃ and Al ₂ O ₃ , or a mixture of Li ₂ O and Al ₂ O ₃ , or a mixture of LiOH and Al ₂ O ₃ , or a mixture of Na ₂ CO ₃ and Al ₂ O ₃ , or a mixture of NaOH and Al ₂ O ₃ , or a mixture of K ₂ CO ₃ and Al ₂ O ₃ , or a mixture of KOH and Al ₂ O ₃ , wherein the molar ratio of the alkali metal element to the Al element in each mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc., wherein the inorganic solder is used as a solder between the lithium ion ceramic electrolyte tubular part and the ceramic back cover of the lithium ion ceramic electrolyte tube.

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

The method for preparing the solid electrolyte provided by the present invention can realize the connection of electrolyte materials including but not limited to sheets with sheets, sheets with tubes, etc., and can obtain a large-sized, high-quality solid electrolyte.

The large-sized solid electrolyte product of the present invention has good air tightness, and its helium leakage rate is not higher than 1×10 ^-8 Pa·m ³ /s, or not higher than 1×10 ^-9 Pa·m ³ /s, or not higher than 1×10 ^-10 Pa·m ³ /s.

The large-size solid electrolyte of the present invention is stable to lithium metal, MCr molten salt, lithium-saturated MCr molten salt, MCl molten salt, and lithium-saturated MCl molten salt.

The ceramic electrolyte tube preparation method of the present invention has the advantages of low technical difficulty, high production efficiency, low equipment cost, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG. 1 is a schematic diagram of the structure of a lithium ion ceramic electrolyte of the present invention.

FIG. 2 is a schematic diagram of a lithium ion ceramic electrolyte structure of the present invention.

FIG. 3 is a schematic diagram of a lithium ion ceramic electrolyte structure of the present invention.

FIG. 4 is a physical picture of a lithium ion ceramic electrolyte of the present invention.

FIG. 5 is a physical picture of a lithium ion ceramic electrolyte of the present invention.

FIG. 6 is a physical picture of a lithium ion ceramic electrolyte of the present invention.

FIG. 7 is a charge and discharge curve diagram of the lithium symmetrical battery of Example 3.

Detailed ways

It should be noted that the following detailed descriptions are exemplary and are intended to provide further illustration of the present invention. The terms used are only for describing specific embodiments and are not intended to limit the exemplary embodiments based on the present invention.

Some detailed embodiments of the present invention will be disclosed below. Although the embodiments are described in the present disclosure, the embodiments of the present invention are not limited to the contents shown. The embodiments disclosed in the present disclosure are only some examples of the embodiments that may be formed in the claims. The remaining embodiments not shown in the claims and their replacements, modifications, equivalent embodiments, etc. are still within the scope of protection.

Embodiment 1:

Please refer to Figure 1.

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The density of the selected tantalum-doped lithium lanthanum zirconate (LLZTO) ceramic electrolyte disc is 90.10%; the density of the LLZTO electrolyte ring is 90.89%.

(2) According to the molar ratio of Li ₂ CO ₃ to Al ₂ O ₃ being 4:1, 16.892 g of Li ₂ CO ₃ and 5.825 g of Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 300 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring with a suitable thickness.

(4) The LLZTO electrolyte disc, the inorganic solder ring and the LLZTO electrolyte ring are arranged in the order shown in FIG. 1 (from bottom to top, the LLZTO electrolyte disc, the inorganic solder ring, and the LLZTO electrolyte ring) and placed in a muffle furnace and sintered at 1100° C. for 30 min.

(5) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 1.2×10 ^-9 Pa·m ³ /s, indicating good air tightness.

(6) Verification of weld corrosion resistance to molten lithium metal: The electrolyte after welding was placed in molten lithium metal and kept at 300°C for 200 hours. After the welding, no obvious reaction was found at the weld, indicating that the inorganic solder was chemically stable to lithium metal.

(7) Verification of weld seam corrosion resistance to MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl and kept at 400°C for 240 hours. After the completion, the molten salt on the surface was cleaned and dried, and it was found that the color of the weld seam had no obvious change. The air tightness test showed that the helium leakage rate was 3.3× ^10-9 Pa· ^m3 /s, and the air tightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to MCl molten salt.

(8) Verification of weld corrosion resistance to lithium-saturated MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl, and lithium metal was added to the upper layer of the molten salt to form a lithium-saturated molten salt, which was kept at 400°C for 200 hours; after completion, the lithium metal and molten salt on the surface were cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was ^2.6 × ^10-9 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to lithium-saturated MCl molten salt.

Embodiment 2:

Please refer to Figure 2.

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The density of the selected niobium-doped lithium lanthanum zirconate (LLZNO) electrolyte sheet is 91.35%; the density of the LLZNO electrolyte cylinder is 91.36%.

(2) According to the molar ratio of LiOH to Al ₂ O ₃ being 10:1, 9.595 g of LiOH and 4.078 g of Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 350 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring with a suitable thickness.

(4) The LLZNO electrolyte sheet, the inorganic solder ring and the LLZNO electrolyte cylinder are placed in the order shown in FIG2 and placed in a muffle furnace and sintered at 1100°C for 20 min.

(5) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 2.3×10 ^-10 Pa·m ³ /s, indicating good air tightness.

(6) Verification of weld corrosion resistance to molten lithium metal: The electrolyte after welding was placed in molten lithium metal and kept at 300°C for 300 hours. After the welding, no obvious reaction was found at the weld, indicating that the inorganic solder was chemically stable to lithium metal.

(7) Verification of weld resistance to MCr molten salt corrosion: The electrolyte after welding was placed in a mixed molten salt of KBr and NaBr and kept at 400°C for 280 hours. After the completion, the molten salt on the surface was cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leak rate was 5.0× ^10-10 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to MCr molten salt.

(8) Verification of weld corrosion resistance to lithium-saturated MCr molten salt: The electrolyte after welding was placed in a mixed molten salt of KBr and NaBr, and lithium metal was added to the upper layer of the molten salt to form a lithium-saturated molten salt, which was kept at 400°C for 300 hours. After the completion, the lithium metal and molten salt on the surface were cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was 4.6× ^10-10 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to lithium-saturated MCr molten salt.

Embodiment 3:

Please refer to Figure 3.

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The density of the selected LLZTO electrolyte sheet is 91.33%; the density of the two LLZTO electrolyte cylinders is 91.35% and 91.33% respectively.

(2) According to the molar ratio of Li ₂ CO ₃ to Al ₂ O ₃ being 5:1, 14.780 g of Li ₂ CO ₃ and 4.078 g of Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 350 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring of appropriate thickness (the inner diameter of the ring is ≥ the outer diameter of the LLZTO electrolyte inner cylinder, the outer diameter of the ring is ≤ the outer diameter of the bottom LLZTO electrolyte sheet, the inner cylinder is placed inside or on the ring, and the outer cylinder is placed on or outside the ring).

(4) The LLZTO electrolyte sheet, the inorganic solder ring and the two LLZTO electrolyte cylinders were placed in the order shown in FIG3 and placed in a muffle furnace and sintered at 1100° C. for 20 min.

(5) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 7.7×10 ^-10 Pa·m ³ /s, indicating good air tightness.

(6) The method and results are consistent with those of Example 2.

(7) The method and results are consistent with those of Example 2.

(8) The method and results are consistent with those of Example 2.

(9) A lithium symmetric battery was assembled using the ceramic electrolyte shown in Figure 6: the inner cylinder was filled with a stainless steel mesh current collector, a mixture of CsBr, KBr and LiBr was filled between the inner and outer cylinders as a molten salt protective layer, and the outer cylinder was filled with molten metal lithium. The lithium symmetric battery was operated at 300°C, and the charge and discharge curves are shown in Figure 7.

Comparative Example 1:

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The density of the selected LLZNO electrolyte sheet is 92.21%; the density of the LLZNO electrolyte cylinder is 92.25%.

(2) According to the molar ratio of Li ₂ CO ₃ to Al ₂ O ₃ being 1:10, 1.478 g Li ₂ CO ₃ and 20.400 g Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 350 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring with a suitable thickness.

(4) The LLZNO electrolyte sheet, the inorganic solder ring, and the LLZNO electrolyte tube are placed in a muffle furnace in order from bottom to top and sintered at 1100°C for 20 min.

(5) After welding, the welds between the LLZTO electrolyte sheet and the LLZTO electrolyte tube have obvious pores, no airtightness, and poor welding performance.

Comparative Example 2:

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The density of the selected LLZTO electrolyte sheet is 91.22%; the density of the LLZTO electrolyte cylinder is 91.27%.

(2) According to the molar ratio of Li ₂ CO ₃ to Al ₂ O ₃ being 12:1, 17.735 g of Li ₂ CO ₃ and 2.040 g of Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 350 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring with a suitable thickness.

(4) The LLZTO electrolyte sheet, the inorganic solder ring and the LLZTO electrolyte tube are placed in a muffle furnace in order from bottom to top and sintered at 1100°C for 20 min.

(5) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 1.3×10 ^-5 Pa·m ³ /s, indicating poor air tightness.

Embodiment 4:

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) The selected LLZTO electrolyte sheet is a ceramic disc with a diameter of 200 mm, a density of 91.21%, and a thickness of 4 mm. Due to its large size, the ceramic disc breaks into two parts from the middle after sintering.

_{(2) K 2 CO 3} and Li ₂ CO ₃ were weighed into a ball mill at a molar ratio of 1 _{: 1, and} ball milled at a rotation speed of 200 r/min for 10 h to obtain a uniformly mixed inorganic salt powder.

(3) Splice the two ceramic plates in (1) into a circular plate and fix it with a stainless steel mold; take an appropriate amount of inorganic salt powder in (2) and spread it on the surface of the circular plate, and keep it at 550°C for 2 hours. After the end, remove the excess inorganic salt on the surface of the circular plate.

(4) The electrolyte disc after welding in (3) was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 8.5×10 ^-10 Pa·m ³ /s, indicating good air tightness.

(5) Verification of weld corrosion resistance to molten lithium metal: The electrolyte disc after welding in (3) was placed in molten lithium metal and kept at 300°C for 300 hours. After the welding, no obvious reaction was found at the weld, indicating that the inorganic salt solder was chemically stable to lithium metal.

(6) Verification of weld resistance to MCr molten salt corrosion: The electrolyte disc after welding in (3) was placed in a mixed molten salt of KBr and NaBr and kept at 400°C for 300 hours. After the molten salt on the surface was cleaned and dried, it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was 7.9× ^10-10 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic salt solder did not undergo chemical corrosion, that is, the inorganic salt solder was stable to MCr molten salt.

(7) Verification of weld resistance to MCl molten salt corrosion: The electrolyte disc after welding in (3) was placed in a mixed molten salt of KCl and NaCl and kept at 400°C for 250 hours. After the completion, the molten salt on the surface was cleaned and dried. It was found that there was no obvious color change at the weld. The air tightness test showed that the helium leakage rate was 7.3× ^10-9 Pa· ^m3 /s, and the air tightness was good. Therefore, it can be judged that the inorganic salt solder did not undergo chemical corrosion, that is, the inorganic salt solder was stable to MCl molten salt.

Embodiment 5:

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(1) First, LLZTO powder was pressed into two rectangular pieces with a length of 10 cm, a width of 5 cm, and a thickness of 4 mm, and then sintered.

(2) According to the molar ratio of KCl to LiCl of 2:3, 14.910 g KCl and 12.717 g LiCl were weighed into a ball mill and milled at a speed of 300 r/min for 10 h to obtain a uniformly mixed inorganic salt powder.

(3) The two rectangular pieces in (1) are assembled into a large square piece with a side length of 10 cm and fixed with a stainless steel mold. The gaps between the pieces are filled with the inorganic salt powder in (2) and kept at 400°C in a muffle furnace for 40 min.

(4) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 1.1×10 ^-9 Pa·m ³ /s, indicating good air tightness.

(5) Verification of weld corrosion resistance to molten lithium metal: The electrolyte after welding was placed in molten lithium metal and kept at 300°C for 200 hours. After the welding, no obvious reaction was found at the weld, indicating that the inorganic solder was chemically stable to lithium metal.

(6) Verification of weld seam corrosion resistance to MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl and kept at 300°C for 280 hours. After the completion, the surface molten salt was cleaned and dried, and it was found that the color of the weld seam had no obvious change. The air tightness test showed that the helium leakage rate was 2.1× ^10-9 Pa· ^m3 /s, and the air tightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to MCl molten salt.

(7) Verification of weld corrosion resistance to lithium-saturated MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl, and lithium metal was added to the upper layer of the molten salt to form a lithium-saturated molten salt, which was kept at 300°C for 260 hours; after completion, the lithium metal and molten salt on the surface were cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was ^1.8 × ^10-9 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to lithium-saturated MCl molten salt.

Embodiment 6:

A method for preparing a lithium ion ceramic electrolyte based on inorganic solder comprises the following steps:

(5) First, LLZTO powder was pressed into four square pieces with a side length of 2 cm and sintered.

(6) According to the molar ratio of K ₂ CO ₃ to Al ₂ O ₃ being 5:1, 34.552 g K ₂ CO ₃ and 5.098 g Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 300 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(7) The four square pieces in (1) are assembled into a large square piece with a side length of 4 cm and fixed with a stainless steel mold. The gaps between the pieces are filled with the inorganic solder powder in (2) and kept at 1000°C in a muffle furnace for 60 min.

(8) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 5.1×10 ^-9 Pa·m ³ /s, indicating good air tightness.

(5) Verification of weld corrosion resistance to molten lithium metal: The electrolyte after welding was placed in molten lithium metal and kept at 300°C for 200 hours. After the welding, no obvious reaction was found at the weld, indicating that the inorganic solder was chemically stable to lithium metal.

(6) Verification of weld corrosion resistance to MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl and kept at 400°C for 200 hours. After the completion, the surface molten salt was cleaned and dried, and it was found that the color of the weld had no obvious change. The air tightness test showed that the helium leakage rate was 4.3× ^10-9 Pa· ^m3 /s, and the air tightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to MCl molten salt.

(7) Verification of weld corrosion resistance to lithium-saturated MCl molten salt: The electrolyte after welding was placed in a mixed molten salt of KCl and NaCl, and lithium metal was added to the upper layer of the molten salt to form a lithium-saturated molten salt, which was kept at 400°C for 200 hours; after completion, the lithium metal and molten salt on the surface were cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was ^3.8 × ^10-9 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to lithium-saturated MCl molten salt.

Embodiment 7:

Please refer to Figure 2.

A method for preparing a solid electrolyte for a sodium ion battery based on an inorganic solder comprises the following steps:

(1) First, Na-β″-Al ₂ O ₃ powder is pressed into cylinders and discs of appropriate sizes and sintered.

(2) According to the molar ratio of Na ₂ CO ₃ to Al ₂ O ₃ being 4:1, 21.198 g of Na ₂ CO ₃ and 5.098 g of Al ₂ O ₃ were weighed into a ball mill and ball milled at a rotation speed of 300 r/min for 10 h to obtain a uniformly mixed inorganic solder powder.

(3) The inorganic solder powder in (2) is pressed into a ring with a suitable thickness.

(4) Arrange the Na-β″-Al ₂ O ₃ electrolyte disc, the inorganic solder ring and the Na-β″-Al ₂ O ₃ electrolyte ring in the order shown in FIG. 2 (from bottom to top, the Na-β″-Al ₂ O ₃ electrolyte disc, the inorganic solder ring and the Na-β″-Al ₂ O ₃ electrolyte ring) in a muffle furnace and sinter at 1000° C. for 60 min.

(5) The welded electrolyte was placed on a helium mass spectrometer leak detector for air tightness test. The helium leak rate was 8.6×10 ^-10 Pa·m ³ /s, indicating good air tightness.

(6) Verification of weld resistance to MCr molten salt corrosion: The electrolyte after welding was placed in a mixed molten salt of KBr and NaBr and kept at 400°C for 250 hours. After the completion, the surface molten salt was cleaned and dried, and it was found that the color of the weld had no obvious change. The airtightness test showed that the helium leak rate was 7.0× ^10-10 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to MCr molten salt.

(7) Verification of weld corrosion resistance to lithium-saturated MCr molten salt: The electrolyte after welding was placed in a mixed molten salt of KBr and NaBr, and lithium metal was added to the upper layer of the molten salt to form a lithium-saturated molten salt, which was kept at 400°C for 300 hours; after completion, the lithium metal and molten salt on the surface were cleaned and dried, and it was found that there was no obvious change in the color of the weld. The airtightness test showed that the helium leakage rate was 7.7× ^10-10 Pa· ^m3 /s, and the airtightness was good. Therefore, it can be judged that the inorganic solder did not undergo chemical corrosion, that is, the inorganic solder was stable to lithium-saturated MCr molten salt.

The present invention provides a method for preparing a spliced solid electrolyte based on inorganic solder, wherein the inorganic solder and the preparation method are applicable to ceramic and glass solid electrolytes, and therefore are also applicable to solid electrolytes in sodium ion batteries and medium and high temperature fuel cells. The specific shape and size of the electrolyte to be prepared will depend on actual needs, and the present invention will not be explained in detail in the embodiments.

Claims (10)

1. A spliced solid electrolyte based on inorganic solder, which is a large-size solid electrolyte for lithium-ion batteries, sodium-ion batteries, medium- and high-temperature fuel cells, etc., including electrolytes of various shapes that are easy to form and sinter, and are welded together in the desired shape by inorganic solder. 2. The spliced solid electrolyte according to claim 1 is characterized in that the inorganic solder includes but is not limited to a mixture of alkali metal compounds and Al ₂ O ₃ , inorganic salts, etc.; the alkali metal compound is a mixture of one or more (two or three) of Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ , KOH, wherein the molar ratio of the alkali metal element to the Al element in the mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc. 3. The spliced solid electrolyte according to claim 1 or 2 is characterized in that the large-size solid electrolyte is a solid electrolyte tubular structure, and the solid electrolyte tubular structure is a lithium ion ceramic electrolyte tube or a sodium ion ceramic electrolyte tube, including a lithium ion ceramic electrolyte tubular portion, a sodium ion ceramic electrolyte tubular portion, and a ceramic bottom seal, wherein the lithium ion ceramic electrolyte tubular portion, the sodium ion ceramic electrolyte tubular portion and the ceramic bottom seal are welded together by an inorganic solder. 4. A method for preparing a spliced solid electrolyte according to any one of claims 1 to 3, wherein the solid electrolyte includes but is not limited to ceramic and glass lithium ion solid electrolytes, sodium ion solid electrolytes and oxygen ion solid electrolytes, etc., and is spliced using inorganic solder, and the preparation steps include: For the solid electrolyte tubular structure: firstly prepare a solid electrolyte straight tube or curved tube with two ends open and easy to form and sinter, whose cross-sectional shapes include but are not limited to circular, hexagonal, rectangular, triangular and four-leaf clover shapes, and a solid electrolyte sheet structure including but not limited to circular for bottom sealing, and then weld the two together with inorganic solder to form a solid electrolyte tubular structure with one end sealed; For solid electrolyte sheet structures or block structures: first prepare a solid electrolyte sheet or block structure that is easy to form and sinter, the shape includes but is not limited to triangle, rectangle, hexagon, irregular shape, etc., and then use inorganic solder to weld the solid electrolyte sheet or block structure together to form a larger size solid electrolyte sheet or solid electrolyte block. 5. The preparation method according to claim 4, characterized in that the solid electrolyte includes but is not limited to ceramic and glass lithium ion solid electrolytes, sodium ion solid electrolytes and oxygen ion solid electrolytes, for example, it can be lanthanum zirconate lithium ceramic electrolyte, _Li2S - _SiS2 glass solid electrolyte, Na-β″ _-Al2O3 sodium ion solid electrolyte and _{ZrO2 -} based oxygen ion solid electrolyte. 6. The preparation method according to claim 4 or 5, characterized in that, for the solid electrolyte tubular structure, the ceramic electrolyte tube comprises a ceramic electrolyte tubular portion and a ceramic bottom seal, wherein the ceramic electrolyte tubular portion and the ceramic bottom seal are welded together by an inorganic solder, comprising: (1) According to the required structure, select the ceramic electrolyte tubular structure and ceramic bottom cover of appropriate size and wait for welding. (2) weighing Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ or KOH and Al ₂ O ₃ , or weighing an inorganic salt, wherein the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc., at a molar ratio of alkali metal elements to Al elements of 1:5 to 10:1; The weighed material is ball-milled at a speed of 200 to 400 r/min for 8 to 20 hours to obtain a uniformly mixed inorganic solder powder. (3) Pressing the inorganic solder in step (2) into a shape according to factors such as the shape of the weld and the thickness of the electrolyte, (4) placing the ceramic electrolyte tubular structure in step (1), the ceramic bottom seal and the inorganic solder in step (3) according to the required structure, and then sintering at 900 to 1200° C. for 10 to 120 min to obtain a ceramic electrolyte tube; Alternatively, the ceramic electrolyte tubular structure in step (1), the ceramic bottom seal and the inorganic solder in step (3) are arranged in a desired structure, and then kept at 400 to 600° C. for 30 to 220 minutes to obtain a ceramic electrolyte tube. 7. The preparation method according to claim 4 or 5, characterized in that, for the solid electrolyte sheet structure, it comprises: (1) According to the required structure, select the ceramic electrolyte sheet structure with appropriate size and wait for welding. (2) weighing Li ₂ CO ₃ , Li ₂ O, LiOH, Na ₂ CO ₃ , NaOH, K ₂ CO ₃ or KOH and Al ₂ O ₃ , or weighing an inorganic salt, wherein the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc., at a molar ratio of alkali metal elements to Al elements of 1:5 to 10:1; The weighed material is ball-milled at a speed of 200 to 400 r/min for 8 to 20 hours to obtain a uniformly mixed inorganic solder powder. (3) splicing the ceramic electrolyte sheet structure in step (1) into a structure of a desired shape, placing the inorganic solder in step (2) according to the desired structure, and then sintering at 900 to 1200° C. for 10 to 120 min to obtain a ceramic electrolyte sheet; Alternatively, the ceramic electrolyte sheet structure in step (1) is spliced into a structure of a desired shape, the inorganic solder in step (2) is placed according to the desired structure, and then kept at 400-650° C. for 30-220 minutes to obtain a ceramic electrolyte sheet. 8. A ceramic electrolyte tube prepared by the preparation method according to any one of claims 4 to 7. 9. An inorganic solder for the spliced solid electrolyte of any one of claims 1-3 or for the preparation method of any one of claims 4-7, the inorganic solder including but not limited to a mixture of _an alkali metal compound and _Al2O3 , an inorganic salt, etc., the alkali metal compound is a mixture of one or more (two or three) of _Li2CO3 , _Li2O , _{LiOH, Na2CO3 , NaOH} , _K2CO3 , KOH, wherein the molar ratio of the alkali metal element to the Al element in the _mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt includes but is not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc. 10. Use of an inorganic solder in preparing a spliced solid electrolyte, the solid electrolyte being a large-size solid electrolyte for lithium-ion batteries, sodium-ion batteries, medium- and high-temperature fuel cells, etc., the inorganic solder including but not limited to a mixture of an alkali metal compound and _{Al2O3 , an inorganic salt, etc., the alkali metal compound being a mixture of one or more (two or three) of Li2CO3, Li2O, LiOH, Na2CO3 , NaOH , K2CO3 , KOH} , wherein _the molar ratio of the alkali metal element to the Al element in the mixture is 1:5 to 10:1, preferably 3:1 to 5:1, for example, it can be 3:1, 4:1, 4.5:1 or 5:1, etc.; the inorganic salt including but not limited to a mixture of one or more of halogen salts, carbonates, sulfates, etc.; wherein the inorganic solder is used as a solder between the tubular part of the electrolyte tubular structure and the ceramic bottom seal, or the inorganic solder is used as a solder between the electrolyte sheet structures.