A method for preparing a high ionic conductivity lithium gallium zirconium oxy-oxide solid-state electrolyte

Abstract

The application relates to a preparation method of a high-ionic-conductivity lithium-gallium-zirconium oxy-based oxide solid-state electrolyte and belongs to the technical field of solid-state electrolytes. A gallium nitrate solution, a zirconium oxychloride solution and a modified gallium ion regulator are slowly added into a lithium nitrate solution, citric acid is stirred and added, the pH value of the solution is adjusted to 3-4, a sol is obtained; the sol is continuously stirred until the sol is changed into a gel; the gel is dried to obtain a dry gel; the dry gel is placed in a muffle furnace for calcination, ball milling and secondary calcination, and then is naturally cooled to obtain the high-ionic-conductivity lithium-gallium-zirconium oxy-based oxide solid-state electrolyte; the modified gallium ion regulator is prepared from allyl diethyl phosphate, toluene, 3-sulfenyl phenyl boronic acid / gallium complex and triethylamine; the lithium-gallium-zirconium oxy-based oxide solid-state electrolyte prepared by the application has high ionic conductivity, can significantly reduce the internal resistance of a battery and prolongs the service life of the battery.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte technology, and in particular to a method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte. Background Technology

[0002] With the rapid development of the new energy industry, lithium-ion batteries, as a highly efficient energy storage device, have been widely used in electric vehicles, portable electronic devices, and other fields. However, traditional liquid lithium-ion batteries suffer from safety hazards such as electrolyte leakage, flammability, and explosion, which seriously restricts their further development. Solid electrolytes, with their advantages of no leakage, non-flammability, and good chemical stability, are considered an effective way to solve the safety problems of liquid lithium-ion batteries and have become a research hotspot in the current lithium-ion battery field.

[0003] Chinese Patent CN119852507A: Provides an oxide solid electrolyte material, its preparation method, and its application, relating to the field of electrolyte material preparation technology. The preparation method includes the following steps: 1) preparing pure-phase lithium borate by mixing BLiO2, Li2O, and B4Li2O7 in a certain proportion under certain conditions; 2) mixing lithium borate with zirconium source, lithium source, and dopant in a certain proportion and ball-milling or wet ball-milling / drying; 3) pressing the mixture into tablets and performing a high-temperature solid-state sintering and crushing process; 4) finally mixing the doped and modified LZBO with a coating agent, ball-milling the mixture, pressing it into tablets, and performing a second high-temperature solid-state sintering and crushing process to obtain the LZBO material.

[0004] Chinese Patent CN119890436B: Provides an oxide solid electrolyte, its preparation method, and a solid battery, comprising the following steps: Under a dry environment, alkali metal fluoride AF and alkali metal salt AM are weighed as starting materials, mixed thoroughly in a homogenizer, the mixture is transferred to a container, and placed in a high-temperature furnace and heated to 100-300℃ at a heating rate of 10-20℃ / min for pre-sintering; the pre-sintered product is placed in a ball mill jar, wet milling solvent is added, and ball milling is performed with milling parameters set to a rotation speed of 200-600 rpm and a milling time of 6-12 hours; the milled material is loaded into a mold and subjected to a pressure of 2t-8t; the pressurized material is then transferred to a high-temperature furnace and sintered at 300℃-700℃, and after cooling, the resulting solid is crushed and ground to finally obtain the oxide solid electrolyte.

[0005] Existing methods for preparing oxide solid electrolytes mainly include solid-phase methods and sol-gel methods. Solid-phase methods require high-temperature and long-term calcination, which easily leads to coarse particles, poor uniformity, and low ionic conductivity of the products. Although sol-gel methods can produce products with smaller particle sizes and better uniformity, the ionic conductivity of the prepared solid electrolytes still needs to be improved, making it difficult to meet the requirements of high-performance solid-state lithium-ion batteries. Summary of the Invention

[0006] To address the above problems, this invention provides a method for preparing a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte, the operation steps of which are as follows, in parts by mass: S1 solution preparation: Dissolve 36-48 parts of lithium nitrate, 18-26 parts of gallium nitrate, and 52-64 parts of zirconium oxychloride in 100-200 parts of deionized water respectively to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution; S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.16-0.31 parts of modified gallium ion regulator are slowly added to lithium nitrate solution while stirring. Then, 174-240 parts of citric acid are added as a chelating agent to adjust the pH of the solution to 3-4. The mixture is heated and stirred to obtain a sol. Stirring continues until the sol transforms into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0007] The S2 reaction temperature is 60-70℃ and the reaction time is 3-4 hours.

[0008] The S3 drying temperature is 80-100℃, and the time is 12-16h.

[0009] The S4 calcination step is as follows: first, heat the temperature to 400-500℃ at a heating rate of 4-5℃ / min and hold for 1-3 hours, then heat the temperature to 800-900℃ at a heating rate of 2-3℃ / min and hold for 4-6 hours.

[0010] The S5 ball mill has a rotation speed of 300-400 r / min and a milling time of 2-3 h.

[0011] The secondary calcination temperature of S5 is 850-950℃, and the time is 3-5h.

[0012] The preparation method of the modified gallium ion regulator is as follows: A1: According to the mass fractions, add 18-36 parts of allyl phosphate diethyl ester, 100-120 parts of toluene, 0.2-0.5 parts of 3-thiophenylboronic acid / gallium complex, and 0.5-1.0 parts of triethylamine, heat to 70-80℃, and react for 6-7 hours; A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized from toluene 2-3 times and dried under vacuum to obtain the modified gallium ion regulator.

[0013] The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: Add 10-15 parts gallium nitrate, 20-40 parts 3-thiophenylboronic acid, and 1.5-5.5 parts triethanolamine to 200-300 parts anhydrous acetonitrile. Stir at 20-35°C for 1-4 hours under argon protection. Remove the anhydrous acetonitrile by distillation, wash the solid 2-5 times, and dry under vacuum to obtain the 3-thiophenylboronic acid / gallium complex.

[0014] Reaction mechanism In the synthesis of the 3-thiophenylboronic acid / gallium complex, Ga³⁺, dissociated from gallium nitrate, acts as a Lewis acid and coordinates with the thiol and borate groups of 3-thiophenylboronic acid and triethanolamine through coordinate bonds, forming a stable complex under argon protection and mild conditions. The complex is purified by distillation, washing, and vacuum drying. During the subsequent modification reaction, Ga³⁺ in this complex undergoes a secondary coordination reaction with the phosphate ester group of allyl phosphate diethyl ester. Triethylamine plays a supporting and promoting role in the reaction. After the reaction is completed at a suitable temperature, the modified gallium ion regulator is finally obtained through rotary evaporation, toluene recrystallization, and vacuum drying.

[0015] Technical effect The modified gallium ion regulator prepared by this invention can generate lithium ion vacancies through doping, effectively reducing the lithium ion migration barrier and thus significantly improving the ionic conductivity of solid electrolytes. At the same time, the regulator can modify grain boundary defects in solid electrolytes, reduce the hindrance in the lithium ion migration process, further reduce grain boundary resistance, and optimize the overall conductivity of the electrolyte.

[0016] Modified gallium ion modifiers can improve the interfacial compatibility between solid electrolytes and electrodes, reduce charge transport resistance at the interface, lower electrode-electrolyte interfacial impedance, enhance the stability of overall electrochemical performance, and avoid the adverse effects of interfacial reactions on battery performance.

[0017] Leveraging the advantages of high ionic conductivity and low interfacial impedance brought by the modified gallium ion regulator, the lithium gallium zirconium oxide solid electrolyte prepared in this invention can effectively reduce the overall internal resistance of the battery, reduce internal energy loss, and thus extend the battery's lifespan, providing support for the application of high-performance solid-state lithium-ion batteries. Attached Figure Description

[0018] Figure 1 This is an electron microscope image of the lithium gallium zirconium oxide solid electrolyte prepared in Example 4. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description is provided in conjunction with embodiments and comparative examples: 1. Ionic conductivity: Detected using AC impedance method.

[0020] 2. Interface impedance: Detected using electrochemical impedance spectroscopy. Example 1

[0021] A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 36g lithium nitrate, 18g gallium nitrate, and 52g zirconium oxychloride in 100g deionized water to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution, respectively. S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.16g of modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 174g of citric acid was added as a chelating agent to adjust the pH of the solution to 3. The mixture was heated and stirred to obtain a sol. Stirring continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0022] The S2 reaction temperature is 60℃ and the reaction time is 3h.

[0023] The S3 drying temperature is 80℃ and the time is 12h.

[0024] The S4 calcination step is as follows: first, heat to 400℃ at a heating rate of 4℃ / min and hold for 1 hour, then heat to 800℃ at a heating rate of 2℃ / min and hold for 4 hours.

[0025] The S5 ball mill has a rotation speed of 300 r / min and a milling time of 2 h.

[0026] The secondary calcination temperature of S5 is 850℃, and the time is 3h.

[0027] The preparation method of the modified gallium ion regulator is as follows: A1: 18g of allyl diethyl phosphate (CAS: 1067-87-4), 100g of toluene, 0.2g of 3-thiophenylboronic acid / gallium complex, and 0.5g of triethylamine were heated to 70℃ and reacted for 6h. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized twice with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0028] The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: 10g gallium nitrate, 20g 3-thiophenylboronic acid (CAS: 352526-01-3), and 1.5g triethanolamine were added to 200g anhydrous acetonitrile. The mixture was stirred at 20°C for 1 hour under argon protection. The anhydrous acetonitrile was removed by distillation, the solid was washed twice, and dried under vacuum to obtain the 3-thiophenylboronic acid / gallium complex. Example 2

[0029] A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 40g lithium nitrate, 21g gallium nitrate and 56g zirconium oxychloride in 140g deionized water respectively to obtain lithium nitrate solution, gallium nitrate solution and zirconium oxychloride solution; S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.2g of modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 190g of citric acid was added as a chelating agent to adjust the pH of the solution to 3. The mixture was heated and stirred to obtain a sol. Stirring continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0030] The S2 reaction temperature is 65℃ and the reaction time is 3.5h.

[0031] The S3 drying temperature is 85℃ and the time is 13h.

[0032] The S4 calcination step is as follows: first, heat the temperature to 440℃ at a heating rate of 4℃ / min and hold for 2 hours, then heat the temperature to 840℃ at a heating rate of 2℃ / min and hold for 5 hours.

[0033] The S5 ball mill has a rotation speed of 350 r / min and a milling time of 2.5 h.

[0034] The secondary calcination temperature of S5 is 880℃, and the time is 4h.

[0035] The preparation method of the modified gallium ion regulator is as follows: A1: 24g of allyl phosphate diethyl ester (CAS: 1067-87-4), 105g of toluene, 0.3g of 3-thiophenylboronic acid / gallium complex, and 0.6g of triethylamine were heated to 75℃ and reacted for 6.5h. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized twice with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0036] The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: 12g gallium nitrate, 25g 3-thiophenylboronic acid (CAS: 352526-01-3), and 2.5g triethanolamine were added to 240g anhydrous acetonitrile. The mixture was stirred at 25°C for 2 hours under argon protection. The anhydrous acetonitrile was removed by distillation, the solid was washed three times, and dried under vacuum to obtain the 3-thiophenylboronic acid / gallium complex. Example 3

[0037] A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 44g lithium nitrate, 24g gallium nitrate and 60g zirconium oxychloride in 180g deionized water respectively to obtain lithium nitrate solution, gallium nitrate solution and zirconium oxychloride solution; S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.27g modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 220g citric acid was added as a chelating agent to adjust the pH of the solution to 4. The mixture was heated and stirred to obtain a sol. Stirring was continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0038] The S2 reaction temperature is 65℃ and the reaction time is 3.5h.

[0039] The S3 drying temperature is 95℃ and the time is 15h.

[0040] The S4 calcination step is as follows: first, heat the temperature to 480℃ at a heating rate of 5℃ / min and hold for 2 hours, then heat the temperature to 880℃ at a heating rate of 3℃ / min and hold for 5 hours.

[0041] The S5 ball mill has a rotation speed of 350 r / min and a milling time of 2.5 h.

[0042] The secondary calcination temperature of S5 is 930℃, and the time is 4 hours.

[0043] The preparation method of the modified gallium ion regulator is as follows: A1: 33g of allyl phosphate diethyl ester (CAS: 1067-87-4), 115g of toluene, 0.4g of 3-thiophenylboronic acid / gallium complex, and 0.8g of triethylamine were heated to 75℃ and reacted for 6.5h. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized three times with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0044] The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: 14g gallium nitrate, 35g 3-thiophenylboronic acid (CAS: 352526-01-3), and 4.5g triethanolamine were added to 280g anhydrous acetonitrile. The mixture was stirred at 30°C for 3 hours under argon protection. The anhydrous acetonitrile was removed by distillation, the solid was washed four times, and dried under vacuum to obtain the 3-thiophenylboronic acid / gallium complex. Example 4

[0045] A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 48g lithium nitrate, 26g gallium nitrate, and 64g zirconium oxychloride in 200g deionized water respectively to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution; S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.31g of modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 240g of citric acid was added as a chelating agent to adjust the pH of the solution to 4. The mixture was heated and stirred to obtain a sol. Stirring was continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0046] The S2 reaction temperature is 70℃ and the reaction time is 4 hours.

[0047] The S3 drying temperature is 100℃ and the time is 16h.

[0048] The S4 calcination step is as follows: first, heat to 500℃ at a heating rate of 5℃ / min and hold for 3 hours, then heat to 900℃ at a heating rate of 3℃ / min and hold for 6 hours.

[0049] The S5 ball mill has a rotation speed of 400 r / min and a milling time of 3 h.

[0050] The secondary calcination temperature of S5 is 950℃, and the time is 5h.

[0051] The preparation method of the modified gallium ion regulator is as follows: A1: 36g of allyl phosphate diethyl ester (CAS: 1067-87-4), 120g of toluene, 0.5g of 3-thiophenylboronic acid / gallium complex, and 1.0g of triethylamine were heated to 80℃ and reacted for 7h. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized three times with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0052] The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: 15g gallium nitrate, 40g 3-thiophenylboronic acid (CAS: 352526-01-3), and 5.5g triethanolamine were added to 300g anhydrous acetonitrile. The mixture was stirred at 35°C for 4 hours under argon protection. The anhydrous acetonitrile was removed by distillation, the solid was washed 5 times, and dried under vacuum to obtain the 3-thiophenylboronic acid / gallium complex.

[0053] Comparative Example 1 A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 36g lithium nitrate, 18g gallium nitrate, and 52g zirconium oxychloride in 100g deionized water to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution, respectively. S2 Sol-Gel Reaction: Gallium nitrate solution and zirconium oxychloride solution were slowly added to lithium nitrate solution while stirring. Then, 174g of citric acid was added as a chelating agent to adjust the pH of the solution to 3. The mixture was heated and stirred to obtain a sol. Stirring was continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0054] The S2 reaction temperature is 60℃ and the reaction time is 3h.

[0055] The S3 drying temperature is 80℃ and the time is 12h.

[0056] The S4 calcination step is as follows: first, heat to 400℃ at a heating rate of 4℃ / min and hold for 1 hour, then heat to 800℃ at a heating rate of 2℃ / min and hold for 4 hours.

[0057] The S5 ball mill has a rotation speed of 300 r / min and a milling time of 2 h.

[0058] The secondary calcination temperature of S5 is 850℃, and the time is 3h.

[0059] Comparative Example 2 A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 36g lithium nitrate, 18g gallium nitrate, and 52g zirconium oxychloride in 100g deionized water to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution, respectively. S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.16g of modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 174g of citric acid was added as a chelating agent to adjust the pH of the solution to 3. The mixture was heated and stirred to obtain a sol. Stirring continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0060] The S2 reaction temperature is 60℃ and the reaction time is 3h.

[0061] The S3 drying temperature is 80℃ and the time is 12h.

[0062] The S4 calcination step is as follows: first, heat to 400℃ at a heating rate of 4℃ / min and hold for 1 hour, then heat to 800℃ at a heating rate of 2℃ / min and hold for 4 hours.

[0063] The S5 ball mill has a rotation speed of 300 r / min and a milling time of 2 h.

[0064] The secondary calcination temperature of S5 is 850℃, and the time is 3h.

[0065] The preparation method of the modified gallium ion regulator is as follows: A1: 18g of allyl diethyl phosphate (CAS: 1067-87-4), 100g of toluene, 0.2g of gallium nitrate, and 0.5g of triethylamine were heated to 70℃ and reacted for 6 hours. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized twice with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0066] Comparative Example 3 A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, comprising the following steps: S1 solution preparation: Dissolve 36g lithium nitrate, 18g gallium nitrate, and 52g zirconium oxychloride in 100g deionized water to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution, respectively. S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.16g of modified gallium ion regulator were slowly added to lithium nitrate solution while stirring. Then, 174g of citric acid was added as a chelating agent to adjust the pH of the solution to 3. The mixture was heated and stirred to obtain a sol. Stirring continued until the sol transformed into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 Ball Milling and Secondary Calcination: The calcined product is ball-milled to obtain powder; the powder is then placed in a muffle furnace for secondary calcination and naturally cooled to obtain a high-ionic-conductivity lithium gallium zirconium oxide solid electrolyte.

[0067] The S2 reaction temperature is 60℃ and the reaction time is 3h.

[0068] The S3 drying temperature is 80℃ and the time is 12h.

[0069] The S4 calcination step is as follows: first, heat to 400℃ at a heating rate of 4℃ / min and hold for 1 hour, then heat to 800℃ at a heating rate of 2℃ / min and hold for 4 hours.

[0070] The S5 ball mill has a rotation speed of 300 r / min and a milling time of 2 h.

[0071] The secondary calcination temperature of S5 is 850℃, and the time is 3h.

[0072] The preparation method of the modified gallium ion regulator is as follows: A1: 18g of allyl diethyl phosphate (CAS: 1067-87-4), 100g of toluene, 0.2g of 3-thiophenylboronic acid (CAS: 352526-01-3), and 0.5g of triethylamine were heated to 70℃ and reacted for 6 hours. A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized twice with toluene and dried under vacuum to obtain the modified gallium ion regulator.

[0073] The test results of the examples and comparative examples are shown in Table 1.

[0074] Table 1 Ionic conductivity (S / cm) Interface impedance (Ω・cm²) Example 1 <![CDATA[1.72×10 -3 ]]> 275 Example 2 <![CDATA[1.75×10 -3 ]]> 269 Example 3 <![CDATA[1.81×10 -3 ]]> 261 Example 4 <![CDATA[1.83×10 -3 ]]> 253 Comparative Example 1 <![CDATA[3.9×10 -4 ]]> 533 Comparative Example 2 <![CDATA[7.5×10 -4 ]]> 345 Comparative Example 3 <![CDATA[8.7×10 -4 ]]> 327 As can be clearly seen from the test results in Table 1, the lithium gallium zirconium oxide solid electrolytes prepared in Examples 1-4 of this invention exhibit significant advantages over Comparative Examples 1-3 in both ionic conductivity and interfacial impedance, two core performance indicators. Specifically, the ionic conductivity of the products in these examples is significantly higher than that of the comparative examples, and the interfacial impedance is significantly lower. Comparative Example 1, due to the absence of a modified gallium ion regulator, and Comparative Examples 2 and 3, due to the use of other substances to replace the 3-thiophenylboronic acid / gallium complex in the regulator preparation, both suffered from a significant decrease in product performance. This comparative result fully demonstrates that the modified gallium ion regulator prepared by the specific process of this invention is a key factor in improving the performance of solid electrolytes, and the developed preparation method can stably produce high-performance solid electrolytes, meeting the core electrolyte requirements of high-performance solid-state lithium-ion batteries.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte, the operation steps of which are as follows, in parts by mass: S1 solution preparation: Dissolve 36-48 parts of lithium nitrate, 18-26 parts of gallium nitrate, and 52-64 parts of zirconium oxychloride in 100-200 parts of deionized water respectively to obtain lithium nitrate solution, gallium nitrate solution, and zirconium oxychloride solution; S2 Sol-Gel Reaction: Gallium nitrate solution, zirconium oxychloride solution, and 0.16-0.31 parts of modified gallium ion regulator are slowly added to lithium nitrate solution while stirring. Then, 174-240 parts of citric acid are added as a chelating agent to adjust the pH of the solution to 3-4. The mixture is heated and stirred to obtain a sol. Stirring continues until the sol transforms into a gel. S3 Drying: Place the gel in a vacuum drying oven to dry and remove moisture, obtaining a dry gel; S4 calcination: The dry gel is placed in a muffle furnace for calcination and then naturally cooled to room temperature to obtain the calcined product; S5 ball milling and secondary calcination: The calcined product is ball milled to obtain powder; the powder is placed in a muffle furnace again for secondary calcination and then naturally cooled to obtain a high ionic conductivity lithium gallium zirconium oxide solid electrolyte. The modified gallium ion regulator is prepared by reacting allyl phosphate, 3-thiophenylboronic acid / gallium complex, and triethylamine. The 3-thiophenylboronic acid / gallium complex is prepared by reacting gallium nitrate, 3-thiophenylboronic acid, and triethanolamine.

2. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The temperature of the S2 heating and stirring reaction is 60-70℃, and the time is 3-4 hours.

3. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The drying temperature of S3 is 80-100℃, and the drying time is 12-16h.

4. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The S4 calcination step is as follows: first, heat the temperature to 400-500℃ at a heating rate of 4-5℃ / min and hold for 1-3 hours, then heat the temperature to 800-900℃ at a heating rate of 2-3℃ / min and hold for 4-6 hours.

5. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The S5 ball milling process is performed at a rotation speed of 300-400 r / min for 2-3 h.

6. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The secondary calcination temperature of S5 is 850-950℃, and the time is 3-5h.

7. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 1, characterized in that: The preparation method of the modified gallium ion regulator is as follows: A1: According to the mass fractions, add 18-36 parts of allyl phosphate diethyl ester, 100-120 parts of toluene, 0.2-0.5 parts of 3-thiophenylboronic acid / gallium complex, and 0.5-1.0 parts of triethylamine, heat to 70-80℃, and react for 6-7 hours; A2: After the reaction is complete, toluene is removed by rotary evaporation. The residue is recrystallized from toluene 2-3 times and dried under vacuum to obtain the modified gallium ion regulator.

8. The method for preparing a high ionic conductivity lithium gallium zirconium oxide solid electrolyte according to claim 7, characterized in that: The preparation method of the 3-thiophenylboronic acid / gallium complex is as follows: Add 10-15 parts gallium nitrate, 20-40 parts 3-thiophenylboronic acid, and 1.5-5.5 parts triethanolamine to 200-300 parts anhydrous acetonitrile. Stir at 20-35°C for 1-4 hours under argon protection. Remove the anhydrous acetonitrile by distillation, wash the solid 2-5 times, and dry under vacuum to obtain the 3-thiophenylboronic acid / gallium complex.

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