Method for manufacturing solid electrolyte of lithium battery

Abstract

The invention provides a method for manufacturing a solid electrolyte of a lithium battery, which comprises the following steps of: taking a ball mill, and placing ethanol (C2H5OH) and water in the ball mill; putting mixed slurry formed by four initial compounds of zirconium source molecules, lanthanum source molecules, lithium source molecules and gallium source molecules, ethanol and water into the ball mill for mixing and grinding; generating small-size compound particles by using a spray dryer; and then carrying out a first-stage vacuum reaction operation to produce the zirconium lanthanum compound. Then, second-stage aerobic reaction operation is carried out, at the moment, in the compound, the other two compounds of the lithium source molecules and the gallium source molecules and O2 are subjected to second-stage aerobic reaction operation with the zirconium lanthanum compound, and heating is continuously carried out to generate modified LLZO (lithium lanthanum zirconium oxide) blocks; and finally, grinding the modified LLZO block mass in another ball mill, and drying in a ball mill oven to obtain the final LLZO powder.

Description

Technical Field

[0001] The present application relates to the technical field of solid electrolytes, and in particular to a method for manufacturing a solid electrolyte for lithium batteries. Background Art

[0002] Traditionally, compounds such as zirconium dioxide (ZrO2), lanthanum oxide (La2O3), and lithium carbonate (Li2CO3) are used to manufacture solid electrolytes for lithium batteries. A mixed slurry of the three initial compounds, zirconium dioxide, lanthanum oxide, and lithium carbonate, is placed in a ball mill in a certain proportion for mixing and grinding, and then sintered once with oxygen during the reaction.

[0003] However, during the sintering process, all oxides become oxygen-deficient. Without sufficient oxygen replenishment, they cannot form the correct cubic phase. Consequently, the phase transformation process is quite chaotic, and the final product contains a combination of tetragonal, cubic, and octagonal lattices, with the overall crystal structure primarily composed of tetragonal crystals. However, the efficiency of conducting lithium ions in a tetragonal crystal structure is poor.

[0004] This type of lithium lanthanum zirconium compound can be used as a solid electrolyte between the anode and cathode of a battery. When in use, the solid electrolyte is placed between the cathode and anode of the battery. When performing work or charging, a lithium ion channel is formed in the solid electrolyte, allowing lithium ions from one electrode to be conducted to the other electrode through this solid electrolyte. Generally, the lithium ion channel produced by this pure lithium lanthanum zirconium compound has a limited effect on the conduction of lithium ions. Although it has a certain effect, it is still not comparable to liquid electrolytes. It will limit the speed of lithium ion conduction, that is, limit the rate of charging and work. Therefore, it is necessary to improve this channel. This case also makes modifications to this point, and improves the speed of ion conduction by doping.

[0005] like Figure 6 As shown, traditionally, after the first stage reaction is completed, the entire reaction temperature is lowered to room temperature, and X-ray diffraction analysis (XRD) is used to measure the completeness of the reaction. After this measurement, the temperature is then raised to proceed to the second stage reaction. This cooling and heating process consumes a considerable amount of time, thereby increasing the time cost of the process.

[0006] Therefore, this case hopes to propose a new reaction process to solve the above-mentioned defects in the existing technology. Summary of the Invention

[0007] Therefore, the purpose of this application is to solve the above-mentioned problems in the prior art. This application proposes a method for manufacturing a solid electrolyte for lithium batteries, wherein oxygen is not added in the first-stage reaction, but oxygen is added in the second-stage reaction, so that the two-stage reaction can be performed separately, and complete La2Zr2O7 (lanthanum zirconate) can be produced in the first-stage reaction, and LLZO particles with a cubic lattice can be produced in the second-stage reaction. Furthermore, in the two-stage reaction, the present application applies good process control without having to lower the reaction temperature of the two stages to room temperature, so the overall reaction speed is accelerated. Furthermore, before the second-stage reaction operation, the La2Zr2O7 (lanthanum zirconate) is placed in the grid groove. Because the La2Zr2O7 (lanthanum zirconate) is dispersed in many tiny storage cells, the reaction rate with oxygen is increased.

[0008] To solve the above-mentioned problems of the prior art, the embodiment of the present application provides a method for manufacturing a solid electrolyte for lithium batteries, which comprises the following steps: step 500: taking a ball mill, and placing ethanol and water in the ball mill; step 510: placing a mixed slurry formed by four initial compounds of zirconium source molecules, lanthanum source molecules, lithium source molecules, and gallium source molecules, and ethanol and water in a certain proportion into the ball mill, and using a plurality of zirconium beads to mix and grind to form compound particles, so that the particle size is less than a specific size; the specific size is 500 nanometers; step 520: applying a spray dryer to spray, fluid impact, and dry the compound particles, which is as follows: placing the compound particles after grinding in the ball mill into the ball mill; The compound particles are sprayed into a spray storage tank of the spray dryer, and then a nozzle of the spray storage tank is used to spray out a fine-particle fluid. The fluid is used to impact the compound particles and turn them into small-sized compound particles. While the fluid is impacting, the small-sized compound particles are dried by a dryer, so that the ethanol, water, impacting fluid and other binders in the small-sized compound particles are evaporated, thereby generating a plurality of holes in the small-sized compound particles. Step 530: Perform the first stage of vacuum reaction operation. First, the small-sized compound particles obtained in step 520 are placed in a reaction tank and continuously heated under vacuum at room temperature. At this time, the The small-sized compound particles will undergo a first-stage vacuum reaction to produce a zirconium-lanthanum compound, i.e., a sintered powder. In this reaction process, because it is a vacuum environment, only the zirconium source molecules and the lanthanum source molecules are added to the reaction, while the other compounds do not produce any reaction. The main reason is that the other compounds must react in an oxygen environment. Step 540: perform a second-stage aerobic reaction operation. At this time, the remaining lithium source molecules and gallium source molecules in the compound will undergo a second-stage aerobic reaction operation with the zirconium-lanthanum compound in the first-stage reaction, and continue to heat and heat to form modified LLZO particles. Because the gallium source molecules have a higher charge and atomic size, the entire The modified LLZO particles form a cubic lattice, and the overall crystal structure thereof can produce larger lithium ion channels, thereby accelerating the lithium ion conduction rate in the solid electrolyte. The modified LLZO particles will agglomerate into a plurality of agglomerates, i.e., forming LLZO agglomerates, each agglomerate comprising a cubic lattice formed by a plurality of modified LLZO particles. Step 550: The agglomerates formed by the modified LLZO particles are then placed in another ball mill for grinding to form a plurality of modified LLZO fine blocks, wherein ethanol or dimethylacetamide is placed in the other ball mill and added to the modified LLZO agglomerates to form a solvent. The weight of the modified LLZO agglomerates accounts for 25% to 35% of the total solvent.The modified LLZO fines are then placed in a ball mill oven and dried to obtain the final LLZO powder; wherein the zirconium source molecule is selected from one of zirconium nitrate, zirconium dioxide, and zirconium hydroxide; the lanthanum source molecule is selected from one of lanthanum nitrate, lanthanum oxide, and lanthanum hydroxide; the lithium source molecule is selected from one of lithium nitrate, lithium carbonate, and lithium hydroxide; and the gallium source molecule is selected from one of gallium nitrate, gallium oxide, and gallium hydroxide.

[0009] The features and advantages of the present application can be further understood from the following description, and please refer to the accompanying drawings when reading. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A flowchart showing the steps of this application;

[0011] Figure 2 A flow chart showing the formation of compound particles according to the present application;

[0012] Figure 3 Showing the schematic diagram of the spray dryer of this application;

[0013] Figure 4 A flow chart showing the formation of LLZO powder in this application;

[0014] Figure 5 A temperature-time relationship diagram showing the reaction process of this application;

[0015] Figure 6 A temperature-time diagram showing a reaction process in the prior art. DETAILED DESCRIPTION

[0016] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] Please refer to Figures 1 to 6 As shown, Figure 1 A flowchart showing the steps of the present application, a method for manufacturing a solid electrolyte for lithium batteries, the method comprising the following steps:

[0018] like Figure 2 As shown, a ball mill 100 is taken, wherein ethanol and water are placed in the ball mill 100, wherein the proportion of ethanol is 25%±10wt% (weight percentage) (step 500).

[0019] A mixed slurry 10 formed by four initial compounds of zirconium source molecules, lanthanum source molecules, lithium source molecules, and gallium source molecules is placed into the ball mill 100 along with ethanol and water in a certain ratio.

[0020] The zirconium source molecule is selected from one of zirconium nitrate, zirconium dioxide, and zirconium hydroxide. The lanthanum source molecule is selected from one of lanthanum nitrate, lanthanum oxide, and lanthanum hydroxide. The lithium source molecule is selected from one of lithium nitrate, lithium carbonate, and lithium hydroxide. The gallium source molecule is selected from one of gallium nitrate, gallium oxide, and gallium hydroxide.

[0021] The processes described in the following examples are illustrative of zirconium dioxide, lanthanum oxide, lithium carbonate, and gallium oxide (Ga2O3), but are not intended to limit the scope of the present invention. The processes described below are applicable to all combinations of the four permitted compounds of the zirconium source, lanthanum source, lithium source, and gallium source described in the previous paragraph.

[0022] A mixed slurry 10 formed from four initial compounds, zirconium dioxide (ZrO2), lanthanum oxide (La2O3), lithium carbonate (Li2CO3), and gallium oxide (Ga2O3), is mixed with ethanol and water in a certain ratio and placed in a ball mill 100 for mixing and grinding using a plurality of zirconium beads 101 (step 510) to a particle size of less than 500 nanometers. The ball mill 100 rotates at 2800 rpm ± 20%, the zirconium beads 101 have a particle size of 0.3 to 1.2 mm, a fill rate of 75% to 90%, and a grinding time of 4 to 10 hours, preferably 5 to 7 hours. The operating temperature is 4 to 30° C., preferably 8 to 20° C., to form compound particles 15. The ratio of the mixed slurry 10 to the original ethanol and water mixture is 25% to 40% by weight.

[0023] like Figure 3 As shown, a spray dryer 200 is used to spray, impact with a fluid, and dry the compound particles 15 (step 520). The method is as follows: the compound particles 15 are placed in a spray storage tank 210 of the spray dryer 200, and then forcefully sprayed from a nozzle 215 of the spray storage tank 210. Subsequently, a plurality of fluid nozzles 220 surrounding the spray storage tank 210 spray fine-grained fluid, which is used to impact the compound particles 15, thereby converting them into small-sized compound particles 20. Because the size of the entire compound particle 20 is reduced, the total surface area of ​​all the small-sized compound particles 20 is relatively increased, which helps to increase the reaction rate.

[0024] In the spray storage tank 210 , the fluid spraying head 220 may spray fine particles of fluid as a spray fluid. Preferably, the spray fluid is sprayed as two-fluid or four-fluid, wherein two-fluid or four-fluid refers to the number of fluid spray paths.

[0025] During the fluid impact process, a dryer 150 is simultaneously used for drying at a temperature of 90° C., so that the binders such as ethanol, water, and the impacting fluid in the small-sized compound particles 20 are evaporated, thereby generating a plurality of pores in the small-sized compound particles 20. These pores can further increase the surface area of ​​the entire compound particles, thereby further increasing the reaction rate.

[0026] Then the first stage of vacuum reaction operation (pressure < 0.1 Torr) is carried out. Figure 4 As shown, the small-sized compound particles 20 obtained in step 520 are first placed in a reaction tank (not shown) under room temperature vacuum environment, and the temperature is increased at a heating rate of 1 to 3°C per minute (preferably 2°C) until the temperature reaches 880 to 980°C. At this temperature, the small-sized compound particles are heated in a vacuum manner to isolate the gas for 6 to 10 hours (preferably 8 hours) (step 530).

[0027] At this time, the small-sized compound particles 20 will undergo the first stage of vacuum reaction, that is, the zirconium source molecules and the lanthanum source molecules in the small-sized compound particles 20 will react to produce La2Zr2O7 compound (zirconium-lanthanum compound), i.e., sintered powder, in this embodiment. Its chemical reaction formula (1) is:

[0028] 2ZrO2+La2O3→La2Zr2O7…………(1)

[0029] In this reaction process, because the environment is vacuum, only ZrO2 and La2O3 are added to the reaction, while the other compounds do not react at all. This is mainly because the other compounds must react in an oxygen environment. In chemical reaction formula (1), the molecular ratio of ZrO2 and La2O3 is 2:1. If the ratio is not as above, the reaction will still occur, but the unreacted initial compounds will still remain in the final product. Therefore, the scope of this application still includes the mixture of various initial compounds in different ratios.

[0030] Next, a second stage of aerobic reaction is performed, raising the temperature of the compound to 930 to 1120°C, preferably 930 to 980°C, and then heating it at this temperature in an oxygen environment for 6 to 10 hours (preferably 8 hours). During this time, the remaining lithium source molecules and gallium source molecules in the compound react. In this embodiment, the two compounds, Li2CO3 and Ga2O3, and O2, react with the compound to undergo the second stage of aerobic reaction (step 540).

[0031] Because the above prior art shows that the Li7La3Zr2O 12When it is a solid electrolyte between the anode and cathode of the battery, the conduction effect of its lithium ion channel on lithium ions is limited. Although it has a certain effect, it is still not comparable to liquid electrolyte. Therefore, it will limit the speed of lithium ion conduction, which means limiting the rate of charging and work.

[0032] The improvement method in this application is to add gallium oxide (Ga2O3) to the reaction of La2Zr2O7+Li2CO3+O2 in the prior art, so that Ga replaces Li7La3Zr2O 12 Part of the Li in the (7-x) Ga x La3Zr2O 12 particles, the Li (7-x) Ga x La3Zr2O 12 is a modified LLZO (Ga doped LLZO). In this embodiment, the four initial compounds of the zirconium source molecule, the lanthanum source molecule, the lithium source molecule, and the gallium source molecule are reacted in the above two stages to produce the lithium lanthanum zirconium gallium molecular compound (Li (7-x) Ga x La3Zr2O 12 ) are all modified LLZO.

[0033] Its chemical reaction formula (2) is as follows:

[0034] 2La2Zr2O7+(7-x)Li2CO3+xGa2O3+La2O3→2Li (7-x) Ga x La3Zr2O 12 +7CO2

[0035] In Li (7-x) Ga x La3Zr2O 12 In the Li7La3Zr2O 12 Because Ga has a higher charge and atomic size, the entire Li (7-x) Ga x La3Zr2O 12 The cubic lattice formed by the solid electrolyte can produce a larger lithium ion channel, thereby accelerating the conduction rate of lithium ions in the solid electrolyte. (7-x) Ga x La3Zr2O 12 The particles will aggregate into a number of clumps (i.e. Li (7-x) Ga x La3Zr2O 12 Cluster 40, LLZO cluster), each cluster contains a plurality of Li(7-x) Ga x La3Zr2O 12 The formed cubic lattice.

[0036] In the above reaction, the molecular ratio of (La2Zr2O7), Li2CO3, xGa2O3, and La2O3 is 2:(7 - x):x:1. If the ratio is not as above, the reaction can still occur, but unreacted initial compounds will remain in the final product. Therefore, the scope of this application still includes mixtures of various initial compounds in different ratios. Here, 0 < x < 0.8, and preferably 0 < x < 0.35.

[0037] In this application, the ratio of the mixed slurry formed by the zirconium source molecules, lanthanum source molecules, lithium source molecules, and gallium source molecules is the ratio corresponding to the reaction coefficients of each molecule in each reaction formula, so as to achieve a complete reaction; when the mixing ratio is not the ratio for complete reaction, the excess molecules will form impurities in the modified LLZO powder. Such operations that produce impurities due to non - proportional mixing are within the scope of the rights of this application.

[0038] Then the above - mentioned Li (7-x) Ga x La3Zr2O 12 The mass of the lump 40 is placed in another ball mill 300, and ethanol (C2H5OH) or DMAC (dimethylacetamide) is placed in the other ball mill 300. After adding the Li (7-x) Ga x La3Zr2O 12 The lump 40, it forms a solvent. The mass of the Li (7-x) Ga x La​​​​​​​​​​​​​​​​​​​The fine pieces 42 are placed in a ball mill oven 350 and dried to obtain the final LLZO powder 44 (lithium lanthanum zirconium oxide solid electrolyte (Lithium Lanthanum Zirconium Oxide; LLZO)). The drying step is such as drying to room temperature, so that the small size of the Li (7-x) Ga x La3Zr2O 12 The binding agent such as ethanol or DMAC in the pellet 42 is evaporated.

[0041] The second stage reaction process is to increase the temperature at a rate of 1 to 3°C per minute (preferably 2°C), add 5 to 10 liters of oxygen per minute for every 200g of the sintered powder, until the temperature reaches 930 to 1120°C, and heat at this temperature for 6 to 10 hours (preferably 8 hours). At this time, the La2Zr2O7 compound that has undergone the first stage vacuum reaction will undergo the reaction of chemical reaction formula (2) to produce Li (7-x) Ga x La3Zr2O 12 , which has a cubic crystal structure. It can be used as a solid electrolyte for lithium batteries to conduct lithium ions. (7-x) Ga x La3Zr2O 12 Because Ga is added, Li7La3Zr2O produced by not adding Ga is 12 , its lithium ion equivalent ratio dropped from 7 to 6.9 to 6.2. (7-x) Ga x La3Zr2O 12 The cubic crystal structure has larger channels, so the conduction rate of lithium ions can be increased.

[0042] Oxygen is not added in the first stage reaction, but is added in the second stage reaction. The advantage is that since oxygen is not added in the first stage reaction, the reaction of chemical reaction formula (2) does not occur in the first stage vacuum reaction. Therefore, in the first stage reaction, only chemical reaction formula (1) is generated, thereby producing high-purity La2Zr2O7. When the first stage reaction is complete and a uniform intermediate is formed, oxygen is added in the second stage reaction, and the reaction of chemical reaction formula (2) is purely carried out. In this case, the overall crystal structure formed is mainly composed of a cubic crystal structure. The crystal structure composed of a cubic crystal structure has a better efficiency in conducting lithium ions.

[0043] If oxygen is added during the first-stage reaction, the resulting crystal structure will primarily consist of a tetragonal lattice. However, a tetragonal lattice has a relatively poor lithium ion conduction efficiency. Therefore, in this application, oxygen is not added during the first-stage reaction, but is added during the second-stage reaction. This allows the first-stage reaction to complete before proceeding to the second-stage reaction, resulting in a crystal structure primarily composed of a cubic lattice. This improves overall lithium ion conduction efficiency.

[0044] Typically, X-ray diffraction analysis (XRD) is used to measure the completeness of the reaction at the end of the first vacuum reaction. However, this measurement requires cooling the temperature from 880 to 930°C to room temperature after the first vacuum reaction, which takes a long time and prolongs the entire process.

[0045] The advantages of this application are that oxygen is not added during the first-stage reaction, but is added during the second-stage reaction, allowing the two-stage reaction to be performed independently. Furthermore, the first-stage reaction can produce complete La2Zr2O7, while the second-stage reaction can produce LLZO particles with a cubic lattice. Furthermore, this application utilizes good process control in both stages, eliminating the need to lower the reaction temperature to room temperature for both stages, thereby accelerating the overall reaction speed.

[0046] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a solid electrolyte for a lithium battery, characterized in that: The method comprises the following steps: Step 500: Take a ball mill and put ethanol and water into the ball mill; Step 510: Place a mixed slurry of the four initial compounds, namely, the zirconium source molecule, the lanthanum source molecule, the lithium source molecule, and the gallium source molecule, in a predetermined ratio with ethanol and water in a ball mill, and mix and grind the mixture using a plurality of zirconium beads to form compound particles having a particle size smaller than a specific size; the specific size is 500 nanometers. Step 520: Using a spray dryer to spray, impact, and dry the compound particles. The method is as follows: the compound particles ground in the ball mill are placed in a spray storage tank of the spray dryer. A nozzle in the spray storage tank is then used to forcefully spray the particles. Subsequently, a plurality of fluid nozzles surrounding the spray storage tank spray fine particles of fluid. The fluid is used to impact the compound particles, thereby reducing the particles to smaller sizes. While the fluid is impacting the small-sized compound particles, the small-sized compound particles are dried in a dryer, so that the binders such as ethanol, water, and the impacting fluid in the small-sized compound particles are evaporated, thereby generating a plurality of pores in the small-sized compound particles; Step 530: Performing a first-stage vacuum reaction operation. First, the small-sized compound particles obtained in step 520 are placed in a reaction tank and continuously heated under a vacuum environment at room temperature. The small-sized compound particles then undergo a first-stage vacuum reaction to produce a zirconium-lanthanum compound, i.e., a sintered powder. Step 540: Perform a second-stage aerobic reaction operation. In this case, the remaining lithium source molecules, the gallium source molecules, and O2 in the compound react with the zirconium-lanthanum compound in the first-stage reaction to perform a second-stage aerobic reaction operation. The temperature is continuously raised and heated to form modified LLZO (lithium lanthanum zirconium oxide) particles. Step 550: The modified LLZO particles are then placed in another ball mill for grinding to form a plurality of modified LLZO lumps. Ethanol or dimethylacetamide is placed in the other ball mill and added to the modified LLZO lumps to form a solvent. The weight of the modified LLZO lumps accounts for 25% to 35% of the total solvent. The modified LLZO pieces are then placed in a ball mill oven for drying to obtain the final LLZO powder; The zirconium source molecule is selected from one of lanthanum nitrate, lanthanum oxide, and lanthanum hydroxide; the lithium source molecule is selected from one of lithium nitrate, lithium carbonate, and lithium hydroxide; and the gallium source molecule is selected from one of gallium nitrate, gallium oxide, and gallium hydroxide.

2. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, wherein: The zirconium source molecule is zirconium dioxide (ZrO2), the lanthanum source molecule is lanthanum oxide (La2O3), the lithium source molecule is lithium carbonate (Li2CO3), and the gallium source molecule is gallium oxide (Ga2O3); The chemical reaction formula (1) of the first stage is: 2ZrO2+La2O3→La2Zr2O7…………(1) The chemical reaction formula (2) of the second stage is: <h2 style=";text-align:left;direction:ltr">2La2Zr2O7+(7-x)Li2CO3+xGa2O3+La2O3→2Li<h2 style=";text-align:left;direction:ltr"> (7-x) <h2 style=";text-align:left;direction:ltr"> Ga<h2 style=";text-align:left;direction:ltr"> x <h2 style=";text-align:left;direction:ltr"> La3Zr2O<h2 style=";text-align:left;direction:ltr"> 12 <h2 style=";text-align:left;direction:ltr"> +7CO2………(2) Modified LLZO is Li (7-x) Ga x La3Zr2O 12 ; where 0 <x<0.8。 3. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, wherein: In the mixture of ethanol and water, the proportion of ethanol accounts for 25%±10wt% by weight; and The ratio of the mixed slurry formed by the four initial compounds of the zirconium source molecule, the lanthanum source molecule, the lithium source molecule and the gallium source molecule to the original mixed solution of ethanol and water is 25% to 40% by weight.

4. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, wherein: In step 510, the rotation speed of the ball mill is 2800 rpm±20%, the size of the zirconium beads is 0.3 to 1.2 mm, the filling rate is 75% to 90%, the grinding time is 4 to 10 hours, and the operating temperature is 4 to 30°C.

5. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, wherein: In the spray storage tank in step 520 , the fluid nozzle sprays fine particles of fluid as spray fluid.

6. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, characterized in that: In step 530 , the first vacuum reaction operation is performed at a heating rate of 1 to 3° C. per minute until the temperature reaches 880 to 980° C., at which the small-sized compound particles are heated in an oxygen-free state for 6 to 10 hours.

7. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, characterized in that: During the second stage of the aerobic reaction in step 540 , the temperature of the compound is raised to 930 to 1120° C. and then heated at this temperature in an aerobic environment for 6 to 10 hours.

8. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, characterized in that: In step 550, a plurality of zirconium beads are mixed and ground in another ball mill to a particle size of less than 500 nanometers. The rotation speed of the other ball mill is 2800 rpm ± 20%, the size of the zirconium beads is 0.3 to 1.2 mm, the filling rate is 75% to 90%, the grinding time is 4 to 10 hours, and the operating temperature is 4 to 30° C. to form smaller-sized modified LLZO blocks. The ball mill is then oven-dried to obtain the modified LLZO powder, so that the binder such as ethanol or DMAC (dimethylacetamide) in the small-sized modified LLZO blocks is evaporated.

9. The method for manufacturing a solid electrolyte for lithium batteries according to claim 2, characterized in that: In the second stage reaction of step 540, the temperature is raised at a rate of 1 to 3°C per minute, and 5 to 10 liters of oxygen are added per minute for every 200 g of the sintered powder until the temperature reaches 930 to 1120°C, and then heated at this temperature for 6 to 10 hours. At this time, the small-sized compound particles that have undergone the first stage vacuum reaction will undergo the reaction of chemical reaction formula (2) to produce modified LLZO, which has a cubic crystal structure. It can be used as a solid electrolyte for lithium batteries to conduct lithium ions.

10. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, characterized in that: After the first stage vacuum reaction is completed, the temperature can be naturally lowered to a predetermined temperature, and then the second stage reaction can be carried out. According to the above conditions, oxygen is added and the temperature is raised to 930 to 1120° C. to carry out the reaction of chemical reaction formula (2); thus, the overall reaction time can be reduced.

11. The method for manufacturing a solid electrolyte for lithium batteries according to claim 1, wherein: The ratio of the mixed slurry formed by the zirconium source molecules, the lanthanum source molecules, the lithium source molecules, and the gallium source molecules is the ratio corresponding to the reaction coefficient of each molecule in each reaction formula, so as to achieve a complete reaction; when the mixing ratio is not the ratio for complete reaction, the excess molecules will form impurities in the modified LLZO powder.

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