Method for preparing grinding aid for sc / o-doped sulfide solid electrolyte

Abstract

The present invention provides a method for preparing a grinding aid for an Sc / O-doped sulfide solid electrolyte. The method comprises: mixing ethanolamine mercaptoacetate, 2-vinyl-5,5-dimethyl-1,3,2-dioxaborolane, 1-allyl-3-ethylimidazole hexafluorophosphate, and potassium ethoxide in a solvent for a reaction, wherein a mercapto-alkenyl addition reaction occurs between the ethanolamine mercaptoacetate and the 2-vinyl-5,5-dimethyl-1,3,2-dioxaborolane, and a mercapto-alkenyl addition reaction occurs between the ethanolamine mercaptoacetate and the 1-allyl-3-ethylimidazole hexafluorophosphate; and after the reaction is complete, removing the solvent to obtain the grinding aid for an Sc / O-doped sulfide solid electrolyte. The grinding aid can improve the microstructure of an electrolyte material and thus improves the electrical conductivity and safety of the electrolyte material.

Description

A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes Technical Field

[0001] This invention relates to the field of battery technology, and specifically to a method for preparing a wear aid for Sc / O doped sulfide solid electrolytes. Background Technology

[0002] Due to their high ionic conductivity and excellent processability, sulfide solid electrolytes have become leaders among fast ion conductors. Among them, Li6PS5Cl type sulfide solid electrolytes are gradually becoming the main choice for the commercialization of sulfide solid-state batteries due to their relatively high ionic conductivity and price advantage. However, Li6PS5Cl type sulfide solid electrolytes are extremely sensitive to moisture in the air and have poor interfacial compatibility with the negative electrode, easily leading to uneven lithium-ion deposition and the formation of lithium dendrites at the interface. In severe cases, this can cause the failure of all-solid-state lithium metal batteries.

[0003] Researchers have made numerous efforts to improve the electrochemical performance of sulfide solid electrolytes. For example, patent CN115051027A discloses a lithium-sulfur silver-germanium ore-type solid electrolyte containing in-situ precipitated lithium halide phases and its preparation method. This electrolyte is obtained by doping a lithium-sulfur silver-germanium ore compound with cation M, wherein the ionic radius of cation M is larger than that of phosphorus. This electrolyte achieves P-site doping by inducing cations M (specifically Al, Si, Sc, Y, Zr) with large ionic radii to occupy P sites through high-energy ball milling, forming a series of novel cation M-doped lithium-sulfur silver-germanium ore sulfide electrolyte materials. This improves the uniform distribution of halogen X within the grains, preventing the formation of a LiX coating layer on the grain surface. Metastable halogen X atoms accompany Li atoms in-situ precipitation of LiX particles, which are dispersed at the grain boundaries, greatly suppressing the deposition and growth of metallic lithium within the electrolyte and significantly enhancing the ability to suppress lithium dendrites, enabling all-solid-state batteries to operate at high current densities.

[0004] References (Zhao Zhengguang, Chen Zhenying, Zhai Guangqun, et al. Preparation of Sc / O doped sulfide solid electrolyte and performance of all-solid-state battery[J]. Energy Storage Science and Technology, 2023, 12(8):2412-2423.) disclose a series of modified sulfide solid electrolytes synthesized using scandium oxide, a rare earth element compound, as a dopant. The results show that when the doping amount of scandium oxide is 0.04, Li 6.08 P 0.96 Sc 0.04 S 4.94 O 0.06 Cl sulfide solid electrolytes exhibit high ionic conductivity, reaching 3.17 × 10⁻⁶. -3The electrolyte exhibits a good crystal structure and excellent all-solid-state battery cycle performance even after being exposed to air for 90 minutes.

[0005] However, there is still room for improvement in the ionic conductivity, cycle stability, and safety of Li6PS5Cl type sulfide solid electrolytes. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes. This grinding aid can improve the microstructure of electrolyte materials, thereby enhancing their conductivity and safety.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes is provided. The method comprises the following steps: adding ethanolamine mercaptoacetate (CAS: 126-97-6), 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane (CAS: 246869-22-7), 1-allyl-3-ethylimidazolium hexafluorophosphate (CAS: 861908-19-2), and potassium ethoxide (CAS: 917-58-8) to a solvent and mixing and reacting them; after the reaction is completed, removing the solvent to obtain the grinding aid.

[0008] Reaction mechanism: ethanolamine mercaptoacetate undergoes a mercapto-alkenyl addition reaction with 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, and ethanolamine mercaptoacetate undergoes a mercapto-alkenyl addition reaction with 1-allyl-3-ethylimidazolium hexafluorophosphate, with potassium ethoxide as a catalyst.

[0009] Preferably, the mass ratio of thioglycolic acid ethanolamine ester, 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 1-allyl-3-ethylimidazolium hexafluorophosphate and potassium ethoxide is 8.28-16.57:0.75-3:0.84-15.68:1.68-4.21.

[0010] Preferably, the solvent is DMF (N,N-dimethylformamide), and more preferably, the ratio of DMF to ethanolamine mercaptoacetate is 100-200 ml : 8.28-16.57 g.

[0011] Preferably, the reaction temperature is 50-70℃ and the reaction time is 50-100min.

[0012] Preferably, the method for removing the solvent is distillation.

[0013] To achieve the above objectives, according to another aspect of the present invention, a grinding aid for Sc / O-doped sulfide solid electrolytes prepared by the above preparation method is provided.

[0014] To achieve the above objectives, according to another aspect of the present invention, a method for preparing a Sc / O-doped sulfide solid electrolyte using the aforementioned grinding aid is provided, the method comprising the following steps:

[0015] (1) Mix Li2S, P2S5, LiCl and Sc2O3 evenly and then ball mill them to obtain a powdered material;

[0016] (2) After pressing the powdered material obtained in step (1) into tablets, vacuum seal it and then perform constant temperature heat treatment to obtain a sheet-like sulfide solid electrolyte material.

[0017] (3) Cool the sheet-like sulfide solid electrolyte material described in step (2) to room temperature, add the Sc / O doped sulfide solid electrolyte grinding aid and grind it into powder to obtain the Sc / O doped sulfide solid electrolyte.

[0018] Preferably, in step (3), the mass of the grinding aid added to the Sc / O doped sulfide solid electrolyte is 0.96%-4.3% of the mass of the sulfide solid electrolyte material.

[0019] Preferably, in step (1), the molar ratio of Li2S, P2S5, LiCl and Sc2O3 is 2.5-2.6:0.4-0.5:1:0.01-0.03, the ball milling speed is set to 500-600 r / min, and the ball milling time is set to 15-20 h.

[0020] Preferably, in step (2), the powder material obtained in step (1) is pressed into a sheet material of 16-19 mm under a pressure of 500-800 Pa.

[0021] Preferably, in step (2), the process conditions for the constant temperature heat treatment are: heat treatment temperature of 500-600℃, heat treatment time of 5-10h, and heating and cooling rates of 0.5℃ / min.

[0022] Preferably, in step (3), the grinding time is 10-20 min.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) Borane functional groups, as a component of grinding aids, can interact with sulfide solid electrolyte materials through their unique chemical properties, thereby improving the crystallinity or microstructure of the materials, thus promoting ion transport and increasing the ionic conductivity of the electrolyte.

[0025] (2) 1-Allyl-3-ethylimidazolium hexafluorophosphate can enhance ion mobility by providing additional charge carriers or changing the electronic structure of the material during the reaction, thereby improving the overall conductivity of the electrolyte material.

[0026] (3) The use of 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane and 1-allyl-3-ethylimidazolium hexafluorophosphate not only helps to improve the charging and discharging efficiency of the battery, but also extends the battery's lifespan and reduces safety risks during battery use. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention, the specific implementation methods and effects of the present invention will be described in detail below with reference to embodiments and comparative examples.

[0028] Example 1

[0029] A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes is as follows:

[0030] 8.28 g of thioglycolic acid ethanolamine ester, 0.75 g of 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 0.84 g of 1-allyl-3-ethylimidazolium hexafluorophosphate and 1.68 g of potassium ethoxide were added to 100 ml of DMF, and then stirred at 50 °C for 50 min. The DMF was then removed by distillation to obtain the grinding aid.

[0031] The method for preparing Sc / O-doped sulfide solid electrolytes using the above-mentioned grinding aids includes the following steps:

[0032] (1) Weigh 119.47g Li2S, 111.13g P2S5, 42.39g LiCl and 4.14g Sc2O3 as starting materials in the glove box, mix them evenly in the zirconia ball mill jar, and then take the sealed zirconia ball mill jar out of the glove box and fix it on the high-energy planetary ball mill for ball milling. The ball milling speed is set to 600r / min and the ball milling time is set to 20h.

[0033] (2) After ball milling, the ball mill jar is placed back into the glove box, and the material is scraped off the wall of the zirconia ball mill jar to obtain a relatively uniform powder. The obtained powder is pressed into 16mm discs under a pressure of 500Pa, and then vacuum-sealed into a quartz tube. The quartz tube is placed in a muffle furnace for isothermal heat treatment. The process conditions for isothermal heat treatment are: heating and cooling rates of 0.5℃ / min, heat treatment temperature of 600℃, and heat treatment time of 10h.

[0034] (3) After the temperature of the muffle furnace drops to room temperature, take out the quartz tube, take out the sheet material from the quartz tube in the glove box, that is, the sulfide solid electrolyte material, add 2.65g of the above grinding aid, and grind it with an agate mortar for 10 minutes to make the electrolyte material into powder, and then put it into a bottle for later use.

[0035] Electrochemical performance testing was conducted: a lithium-lithium symmetric battery was assembled using the powdered sulfide solid electrolyte material obtained above, and its performance was tested at 0.95 mA / cm². 2 The lithium-ion insertion / extraction cycle was operated at the critical current density (CCD) and the stable operating time was 255h.

[0036] Example 2

[0037] A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes is as follows:

[0038] 12.43 g of thioglycolic acid ethanolamine ester, 1.5 g of 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 7.42 g of 1-allyl-3-ethylimidazolium hexafluorophosphate and 2.95 g of potassium ethoxide were added to 150 ml of DMF, and then stirred at 60 °C for 75 min. The DMF was removed by distillation to obtain the grinding aid.

[0039] The method for preparing Sc / O-doped sulfide solid electrolytes using the above-mentioned grinding aids includes the following steps:

[0040] (1) Weigh 116.7g Li2S, 106.69g P2S5, 42.39g LiCl and 2.758g Sc2O3 in the glove box as starting materials, mix them evenly in the zirconia ball mill jar, and then take the sealed zirconia ball mill jar out of the glove box and fix it on the high-energy planetary ball mill for ball milling. The ball milling speed is set to 550r / min and the ball milling time is set to 17h.

[0041] (2) After ball milling, the ball mill jar was placed back into the glove box, and the material was scraped off the wall of the zirconia ball mill jar to obtain a relatively uniform powder. The obtained powder was pressed into 18 mm discs under a pressure of 600 Pa, and then vacuum-sealed into a quartz tube. The quartz tube was placed in a muffle furnace for isothermal heat treatment. The isothermal heat treatment process conditions were: heating and cooling rates of 0.5 °C / min, heat treatment temperature of 550 °C, and heat treatment time of 7 h.

[0042] (3) After the temperature in the muffle furnace drops to room temperature, take out the quartz tube, take out the sheet material from the quartz tube in the glove box, that is, the sulfide solid electrolyte material, add 5.3g of the above grinding aid, and grind it with an agate mortar for 15 minutes to make the electrolyte material into powder, and then put it into a bottle for later use.

[0043] Electrochemical performance testing was conducted: a lithium-lithium symmetric battery was assembled using the powdered sulfide solid electrolyte material obtained above, and its performance was tested at 0.95 mA / cm². 2 The lithium-ion insertion / extraction cycle was operated at the critical current density (CCD) and the stable operating time was 315 hours.

[0044] Example 3

[0045] A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes is as follows:

[0046] 16.57g of thioglycolic acid ethanolamine ester, 3g of 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 15.68g of 1-allyl-3-ethylimidazolium hexafluorophosphate and 4.21g of potassium ethoxide were added to 200ml of DMF, stirred at 70℃ for 100min, and the DMF was removed by distillation to obtain the grinding aid.

[0047] The method for preparing Sc / O-doped sulfide solid electrolytes using the above-mentioned grinding aids includes the following steps:

[0048] (1) Weigh 114.9g Li2S, 88.9g P2S5, 42.39g LiCl and 1.379g Sc2O3 in the glove box as starting materials, mix them evenly in the zirconia ball mill jar, and then take the sealed zirconia ball mill jar out of the glove box and fix it on the high-energy planetary ball mill for ball milling. The ball milling speed is set to 500r / min and the ball milling time is set to 15h.

[0049] (2) After ball milling, the ball mill jar is placed back into the glove box, and the material is scraped off the wall of the zirconia ball mill jar to obtain a relatively uniform powder. The obtained powder is pressed into 19 mm discs under a pressure of 800 Pa, and then vacuum-sealed into a quartz tube. The quartz tube is placed in a muffle furnace for isothermal heat treatment. The isothermal heat treatment process conditions are: heating and cooling rates of 0.5℃ / min, heat treatment temperature of 500℃, and heat treatment time of 5 h.

[0050] (3) After the temperature of the muffle furnace drops to room temperature, take out the quartz tube, take out the sheet material from the quartz tube in the glove box, that is, the sulfide solid electrolyte material, add 10.6g of the above grinding aid, and grind it with an agate mortar for 20 minutes to make the electrolyte material into powder, and then put it into a bottle for later use.

[0051] Electrochemical performance testing was conducted: a lithium-lithium symmetric battery was assembled using the powdered sulfide solid electrolyte material obtained above, and its performance was tested at 0.95 mA / cm². 2The lithium-ion insertion / extraction cycle was operated at the critical current density (CCD) and the stable operating time was 322h.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 1 is that no grinding aid is added in step (3) of preparing the Sc / O doped sulfide solid electrolyte. The sheet-like sulfide solid electrolyte material is ground in an agate mortar for 15 minutes to obtain a powdered electrolyte material.

[0054] Electrochemical performance testing was conducted: a lithium-lithium symmetric battery was assembled using the obtained powdered sulfide solid electrolyte material, and its performance was tested at 0.95 mA / cm². 2 The lithium-ion insertion / extraction cycle was operated at the critical current density (CCD) and the stable operation time was 100h.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 1 is that no ionic liquid is added to the grinding aid, but otherwise it is the same as Example 1.

[0057] A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes is as follows:

[0058] 12.43 g of ethanolamine mercaptoacetate, 1.5 g of 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, and 2.95 g of potassium ethoxide were added to 150 ml of DMF, and then stirred at 60 °C for 75 min. The DMF was removed by distillation to obtain the grinding aid.

[0059] Electrochemical performance testing was conducted: a lithium-lithium symmetric battery was assembled using the powdered sulfide solid electrolyte material obtained above, and its performance was tested at 0.95 mA / cm². 2 The lithium-ion insertion / extraction cycle can be operated at the critical current density (CCD) and the stable operating time can be 224h.

Claims

1. A method for preparing a grinding aid for Sc / O doped sulfide solid electrolytes, characterized in that, include: The ethanolamine mercaptoacetate, 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 1-allyl-3-ethylimidazolium hexafluorophosphate, and potassium ethoxide were mixed and reacted in a solvent. The ethanolamine mercaptoacetate underwent a mercapto-alkenyl addition reaction with 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, and the ethanolamine mercaptoacetate underwent a mercapto-alkenyl addition reaction with 1-allyl-3-ethylimidazolium hexafluorophosphate. After the reaction was completed, the solvent was removed to obtain the grinding aid for the Sc / O doped sulfide solid electrolyte.

2. The method for preparing the grinding aid for Sc / O doped sulfide solid electrolyte according to claim 1, characterized in that, The mass ratio of thioglycolic acid ethanolamine ester, 2-vinyl-5,5-dimethyl-1,3,2-dioxoborane, 1-allyl-3-ethylimidazolium hexafluorophosphate, and potassium ethoxide is: 8.28-16.57∶0.75-3∶0.84-15.68∶1.68-4.21。 3. The method for preparing the grinding aid for Sc / O doped sulfide solid electrolyte according to claim 1, characterized in that, The solvent is DMF.

4. The method for preparing the grinding aid for Sc / O doped sulfide solid electrolyte according to claim 1, characterized in that, The reaction temperature is 50-70℃, and the reaction time is 50-100 min.

5. The method for preparing the grinding aid for Sc / O doped sulfide solid electrolyte according to claim 1, characterized in that, The method for removing the solvent is distillation.

6. The grinding aid for Sc / O doped sulfide solid electrolyte prepared by the preparation method according to any one of claims 1-5.

7. A method for preparing a Sc / O-doped sulfide solid electrolyte using the grinding aid of the Sc / O-doped sulfide solid electrolyte according to claim 6, characterized in that, Includes the following steps: (1) Mix Li2S, P2S5, LiCl and Sc2O3 evenly and then ball mill them to obtain a powdered material; (2) After pressing the powdered material obtained in step (1) into tablets, vacuum seal it and then perform constant temperature heat treatment to obtain a sheet-like sulfide solid electrolyte material. (3) Cool the sheet-like sulfide solid electrolyte material described in step (2) to room temperature, add the Sc / O doped sulfide solid electrolyte grinding aid and grind it into powder to obtain the Sc / O doped sulfide solid electrolyte.

8. The method for preparing Sc / O-doped sulfide solid electrolyte according to claim 7, characterized in that, In step (3), the mass of the grinding aid added to the Sc / O doped sulfide solid electrolyte is 0.96%-4.3% of the mass of the Sc / O doped sulfide solid electrolyte material.

9. The method for preparing Sc / O-doped sulfide solid electrolyte according to claim 7, characterized in that, In step (1), the molar ratio of Li2S, P2S5, LiCl and Sc2O3 is 2.5-2.6:0.4-0.5:1:0.01-0.03, the ball milling speed is set to 500-600 r / min, and the ball milling time is set to 15-20 h.

10. The method for preparing Sc / O-doped sulfide solid electrolyte according to claim 7, characterized in that, In step (2), the process conditions for the constant temperature heat treatment are: heat treatment temperature of 500-600℃, heat treatment time of 5-10h, and heating and cooling rates of 0.5℃ / min.