Method for recycling and regenerating waste garnet type oxide solid electrolyte

Abstract

The invention discloses a method for recycling and regenerating a waste garnet type oxide solid electrolyte. The method comprises the following steps: (1) disassembling a waste solid battery to obtain the waste garnet type oxide solid electrolyte; the surface of the waste garnet type oxide solid electrolyte is polished, and the polished garnet type oxide solid electrolyte is obtained; (2) crushing the polished garnet type oxide solid electrolyte into powder to obtain solid electrolyte powder; carrying out annealing treatment on the solid electrolyte powder in an inert atmosphere to obtain annealed solid electrolyte powder; (3) uniformly mixing the annealed solid electrolyte powder, a binder, a lithium supplement agent and an organic solvent to obtain a mixture; and putting the mixture into a mold, pressurizing, adding the pressurized mold containing the mixture into a sintering furnace, and carrying out heat treatment in an inert atmosphere to obtain the regenerated garnet type oxide solid electrolyte sheet.

Description

Technical Field

[0001] The invention belongs to the technical field of waste solid electrolyte recovery, and in particular relates to a method for recovering and regenerating waste garnet-type oxide solid electrolytes.

[0002] Background technology Compared to traditional liquid organic electrolytes, solid electrolytes offer advantages in safety and stability. Therefore, solid-state batteries using solid electrolytes can provide higher energy density, durability, and safety. Currently, solid electrolytes can be categorized into oxide solid electrolytes, sulfide solid electrolytes, and polymer solid electrolytes, depending on the material used. Garnet oxide solid electrolytes offer the best overall performance and, therefore, the best applicability.

[0003] In recent years, with the continuous breakthroughs in the technical bottlenecks of oxide solid electrolytes and solid-state batteries, a large number of oxide solid-state batteries will inevitably be put into use in the foreseeable future. Along with this comes the proper disposal of spent solid electrolytes. Since the production cost of oxide solid electrolytes is generally high, recycling them can effectively reduce production costs.

[0004] The direct regeneration technology of oxide solid electrolytes has been verified on a laboratory scale and can be used to recycle solid-state batteries. For example, patent CN115441080A discloses a direct recovery and regeneration method for oxide solid electrolytes. First, the surface of the oxide-based solid electrolyte after short circuit is pretreated, then heat treated, and finally its surface is ground and polished to complete the recovery and regeneration of the electrolyte. This process eliminates lithium dendrites and restores the electrochemical performance of the solid electrolyte to the level before the short circuit; however, this method may lead to local lithium enrichment problems, increasing the risk of short circuit in the regenerated battery; in addition, the microcracks generated in the solid electrolyte during recycling cannot be repaired, resulting in an increase in the impedance of the regenerated electrolyte. For example, patent CN119833804A discloses a method for directly regenerating garnet oxide solid electrolytes from waste solid-state batteries. The method involves first crushing the disassembled oxide solid electrolyte and leaching the crushed powder to obtain a lithium-containing filtrate and a filter residue. The lithium-containing filtrate is then evaporated and concentrated to precipitate lithium to obtain lithium carbonate. The filter residue is then mixed with lithium carbonate and calcined to obtain oxide solid electrolyte powder. Finally, the oxide solid electrolyte powder is pressed into tablets and calcined a second time to obtain regenerated oxide solid electrolyte tablets. While this process can simultaneously eliminate lithium dendrites and microcracks, it is relatively complex, energy-intensive, and the cost of regenerating the oxide solid electrolyte is high. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for recycling and regenerating waste garnet-type oxide solid electrolytes with simple process and low cost.

[0006] The present invention provides a method for recovering and regenerating waste garnet-type oxide solid electrolyte, comprising the following steps: (1) dismantling waste solid-state batteries to obtain waste garnet-type oxide solid electrolytes; polishing the surface of the waste garnet-type oxide solid electrolytes to obtain polished garnet-type oxide solid electrolytes; (2) crushing the polished garnet oxide solid electrolyte into powder to obtain solid electrolyte powder; annealing the solid electrolyte powder under an inert atmosphere to obtain annealed solid electrolyte powder; (3) The annealed solid electrolyte powder, binder, lithium supplement and organic solvent are uniformly mixed to obtain a mixture; the mixture is placed in a mold and pressurized; the mold containing the mixture and pressurized is placed in a sintering furnace and heat-treated under an inert atmosphere to obtain a regenerated garnet-type oxide solid electrolyte sheet.

[0007] Preferably, in step (1), the chemical formula of the waste garnet-type oxide solid electrolyte is Li x A2(LaO4)3, wherein A is one or more metals selected from Al, Fe, Ga, Zr, Ta, and Sc, and x>0.

[0008] Preferably, in step (2), the crushing is performed by grinding, and the crushing time is 10 to 40 minutes; more preferably, it is 20 to 30 minutes.

[0009] Preferably, in step (2), the heating rate of the annealing treatment is 5-10°C / min, more preferably 5-8°C / min; the temperature of the annealing treatment is 160-300°C, more preferably 160-250°C; and the holding time of the annealing treatment is 30-120 min, more preferably 40-100 min.

[0010] Preferably, in step (3), the binder is one of polyvinylidene fluoride, polytetrafluoroethylene, and polypropylene carbonate, preferably polyvinylidene fluoride; the lithium supplement is one of lithium carbonate, lithium hydroxide, and lithium perchlorate, more preferably lithium perchlorate; and the organic solvent is one of anhydrous acetonitrile, N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide, more preferably N-dimethylformamide.

[0011] Preferably, in step (3), the mass ratio of the solid electrolyte powder, the binder, the lithium supplement and the organic solvent is 60:0.5~2:1~10:10~20, more preferably 60:1~2:5~10:10~15.

[0012] Preferably, in step (3), the pressurized pressure is 50-200 bar, more preferably 80-150 bar; the heat treatment temperature is 100-150°C, more preferably 100-130°C; and the heat treatment holding time is 30-120 min, more preferably 60-120 min.

[0013] Preferably, in steps (2) and (3), the inert atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0014] In the destruction mechanism of garnet oxide solid electrolytes, factors such as local chemical reactions at the interface layer, microcracks within the electrolyte, and lithium dendrites are the main causes of high impedance and battery short circuits. However, the vast majority of solid electrolytes still maintain good activity. If factors such as local chemical reaction layers, microcracks, and lithium dendrites are eliminated, spent solid electrolytes can be recycled without complex processing.

[0015] In the method of the present invention, the surface of the waste garnet-type oxide solid electrolyte is first polished to remove the local chemical reaction layer; the waste garnet-type oxide solid electrolyte is crushed and re-pressed into sheets to eliminate microcracks; and an annealing treatment is performed under an inert atmosphere to ensure the crystal structure stability of the solid electrolyte during the treatment process. In addition, the lithium dendrites are also broken by a crushing method. At the same time, the lithium dendrites tend to combine with the oxide electrolyte during the annealing treatment, and then are eliminated in the pressurized heat treatment step.

[0016] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: 1) The recycling and regeneration method of the present invention can remove defects such as local chemical reaction layers, microcracks and lithium dendrites in waste garnet-type oxide solid electrolytes, and has simple processes, low energy consumption and low recycling costs.

[0017] 2) The annealing temperature and heat treatment temperature in the recovery and regeneration method of the present invention are both low, which can effectively reduce recovery energy consumption and save recovery costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A process flow chart of the method for recovering and regenerating waste garnet-type oxide solid electrolytes of the present invention.

[0019] Figure 2This is the XRD spectrum of the regenerated LLZO-R sheet in Example 1.

[0020] Figure 3 This is the XRD spectrum of the regenerated LLZO-S sheet in Comparative Example 1.

[0021] Figure 4 This is the XRD spectrum of the LLNO-R sheet regenerated in Example 2.

[0022] Figure 5 This is the XRD spectrum of the LLNO-S sheet regenerated in Comparative Example 2. DETAILED DESCRIPTION

[0023] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0024] A method for recovering and regenerating waste garnet-type oxide solid electrolyte comprises the following steps: (1) Disassembling waste solid-state batteries to obtain waste garnet-type oxide solid electrolytes; firstly polishing the surface of the waste garnet-type oxide solid electrolyte to obtain a polished garnet-type oxide solid electrolyte; (2) crushing the polished garnet oxide solid electrolyte into powder to obtain solid electrolyte powder; annealing the solid electrolyte powder under an inert atmosphere to obtain annealed solid electrolyte powder; (3) The annealed solid electrolyte powder, binder, lithium supplement and organic solvent are uniformly mixed to obtain a mixture; the mixture is placed in a mold and pressurized; the mold containing the mixture and pressurized is placed in a sintering furnace and heat-treated under an inert atmosphere to obtain a regenerated garnet-type oxide solid electrolyte sheet.

[0025] In the recovery and regeneration method of the present invention, the waste garnet-type oxide solid electrolyte is first polished to effectively remove the chemical reaction layer on the surface; then it is crushed, which will cause the lithium dendrites to be broken, which is conducive to the subsequent further reaction with the solid electrolyte; then the garnet-type oxide solid electrolyte is stabilized by annealing to ensure the stability of its crystal structure and also facilitate the combination of lithium dendrites with the solid electrolyte; finally, it is combined with other components and re-pressed and heat-treated under pressure to eliminate the lithium dendrites; at the same time, the crushed and re-pressed into sheets can also eliminate microcracks, and finally a regenerated garnet-type oxide solid electrolyte sheet is obtained.

[0026] Preferably, in step (1), the chemical formula of the waste garnet-type oxide solid electrolyte is Li x A2(LaO4)3, wherein A is one or more metals selected from Al, Fe, Ga, Zr, Ta, and Sc, and x>0.

[0027] Preferably, in step (2), the crushing is performed by grinding, and the crushing time is 10 to 40 minutes; more preferably 20 to 30 minutes; including but not limited to 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, etc.

[0028] Preferably, in step (2), the heating rate of the annealing treatment is 5-10°C / min, more preferably 5-8°C / min, including but not limited to 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.; the temperature of the annealing treatment is 160-300°C, more preferably 160-250°C, including but not limited to 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, etc.; the holding time of the annealing treatment is 30-120min, more preferably 40-100min, including but not limited to 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.

[0029] In the present invention, the annealing temperature is controlled at 160-300°C. Below 160°C, the stability of the garnet oxide solid electrolyte crystal structure is poor, while above 300°C, the stability of the garnet oxide solid electrolyte crystal structure will not be further improved and energy consumption will be increased.

[0030] Preferably, in step (3), the binder is one of polyvinylidene fluoride, polytetrafluoroethylene, and polypropylene carbonate, preferably polyvinylidene fluoride; the lithium supplement is one of lithium carbonate, lithium hydroxide, and lithium perchlorate, more preferably lithium perchlorate; and the organic solvent is one of anhydrous acetonitrile, N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide, more preferably N-dimethylformamide.

[0031] Preferably, in step (3), the mass ratio of the solid electrolyte powder, the binder, the lithium supplement and the organic solvent is 60:0.5~2:1~10:10~20, more preferably 60:1~2:5~10:10~15.

[0032] Preferably, in step (3), the pressurized pressure is 50-200 bar, more preferably 80-150 bar, including but not limited to 50 bar, 60 bar, 70 bar, 80 bar, 90 bar, 100 bar, 110 bar, 120 bar, 130 bar, 140 bar, 150 bar, 160 bar, 170 bar, 180 bar, 190 bar, 200 bar, etc.; the heat treatment temperature is 100-150 ° C, more preferably 100-130 ° C, including but not limited to 100 ° C, 110 ° C, 120 ° C, 130 ° C, 140 ° C, 150 ° C, etc.; the heat treatment holding time is 30-120 min, more preferably 60-120 min, including but not limited to 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc.

[0033] In the recovery and regeneration process of the present invention, the pressurized heat treatment after crushing can not only eliminate microcracks in the solid electrolyte, but also eliminate lithium dendrites, thereby improving the performance of the regenerated garnet-type oxide solid electrolyte.

[0034] Preferably, in steps (2) and (3), the inert atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0035] The process flow chart of the method for recycling and regenerating waste garnet-type oxide solid electrolyte in the present invention is as follows: Figure 1 The specific preparation method can be found in the examples.

[0036] Example 1 1) Dismantle the waste solid-state battery to obtain garnet-type solid electrolyte Li 6.4 La3Zr2O 12(LLZO); polish the LLZO with 1000-mesh sandpaper until the surface is smooth and free of contaminants to obtain polished LLZO; grind the polished LLZO with a mortar for 20 minutes to obtain LLZO powder.

[0037] 2) The LLZO powder was heated to 160°C at a rate of 5°C / min under an argon atmosphere, kept at that temperature for 100 min, and then cooled to room temperature to obtain annealed LLZO powder.

[0038] 3) The annealed LLZO powder, polyvinylidene fluoride, lithium perchlorate, and NN dimethylformamide were mixed in a mass ratio of 60:1:5:10 and ground for 20 minutes to obtain a mixture; the mixture was placed in a cylindrical mold with a diameter of 15 mm and a pressure of 80 bar was applied at the same time. The mixture and the pressurized mold were placed in a muffle furnace under an inert atmosphere at a temperature of 100°C for 120 minutes. After the insulation, a regenerated LLZO-R sheet was obtained.

[0039] The LLZO-R sheet obtained in this example was scanned and tested using an X-ray diffractometer and an electrochemical workstation to obtain the XRD pattern of LLNO-R. Figure 2 As shown, the ionic conductivity was measured to be 5.1*10 -4 S / cm.

[0040] from Figure 2 It can be seen that the diffraction peaks of the LLNO-R sheet obtained by the recycling-regeneration process in Example 1 are consistent with the PDF#45-0109 standard card, and there are no impurity peaks, which proves that the crystal structure of the regenerated material is good.

[0041] Comparative Example 1 The process is basically the same as Example 1, except that the annealing treatment in step 2) is omitted. The LLZO powder in step 1) is substituted for the annealed LLZO powder in step 3), and an LLZO-S sheet is finally obtained.

[0042] The LLZO-S sheet obtained in this comparative example was scanned and tested using an X-ray diffractometer and an electrochemical workstation to obtain the XRD pattern of the LLZO-S sheet. Figure 3 As shown, the ionic conductivity was measured to be 3.0*10 -4 S / cm.

[0043] from Figure 3It can be seen that the diffraction peak of the unannealed LLZO-S sheet at 2θ=16.8° is shifted to the right by about 0.2°, and some diffraction peaks are relatively broadened and accompanied by splitting. Since the cubic phase of LLZO has a more regular crystal structure than the tetragonal phase, the atomic arrangement is highly ordered, and the interplanar spacing is relatively consistent, the width of the diffraction peak is narrower. The unannealed LLZO-S sheet in this comparative example has defects in its own crystal structure and the tetragonal phase transformation that occurs during the recycling process, resulting in the above changes in the XRD diagram.

[0044] The ionic conductivity of the LLZO-S recovered in this comparative example is also lower than that in Example 1. This may be because the crystal structure is unstable due to the lack of annealing, resulting in a decrease in ionic conductivity. It may also be because the lithium dendrites are not completely eliminated due to the lack of annealing, resulting in a decrease in ionic conductivity.

[0045] Comparative Example 2 1) Dismantle the waste solid-state battery to obtain garnet-type solid electrolyte Li 6.4 La3Zr2O 12 (LLZO); polishing the LLZO with 1000-grit sandpaper until the surface is smooth and free of contaminants to obtain polished LLZO; heating the polished LLZO to 160°C at a rate of 5°C / min under an argon atmosphere, keeping the temperature for 100 minutes, and then cooling to room temperature to obtain annealed LLZO.

[0046] 2) Grind the annealed LLZO in a mortar for 20 min to obtain LLZO powder.

[0047] 3) LLZO powder, polyvinylidene fluoride, lithium perchlorate, and N-N-dimethylformamide were mixed in a mass ratio of 60:1:5:10 and ground for 20 minutes to obtain a mixture; the mixture was placed in a cylindrical mold with a diameter of 15 mm and a pressure of 80 bar was applied at the same time; the mixture and the pressurized mold were placed in a muffle furnace under an inert atmosphere at a temperature of 100°C for 120 minutes. After the insulation, a regenerated LLZO-R sheet was obtained.

[0048] The LLNO-R sheet obtained in this comparative example was tested using an electrochemical workstation, and the ionic conductivity of the LLNO-R sheet was found to be 2.3*10 -4 The conductivity of the regenerated LLZO-R sheet prepared in this comparative example is significantly lower than that of Example 1, indicating that the annealing treatment before crushing may not be effective in removing lithium dendrites and stabilizing the crystal form.

[0049] Example 2 1) Dismantle the waste solid-state battery to obtain garnet-type oxide solid electrolyte Li6.4 La3Nb2O 12 (LLNO); polish the LLNO with 1000-grit sandpaper until the surface is smooth and free of contaminants, thereby obtaining polished LLNO. Grind the polished LLNO in a mortar for 40 minutes to obtain LLZO powder.

[0050] 2) The LLNO powder was heated to 200°C at a rate of 7°C / min, kept at this temperature for 70 min, and then cooled to room temperature to obtain annealed LLNO powder.

[0051] 3) The annealed LLNO powder, polyvinylidene fluoride, lithium perchlorate, and NN-dimethylformamide were mixed in a mass ratio of 60:1.5:7.5:12.5 and ground for 20 minutes to obtain a mixture. The mixture was placed in a cylindrical mold with a diameter of 15 mm and a pressure of 120 bar was applied. The mixture and the pressurized mold were placed in a muffle furnace under an argon atmosphere at 120°C for 60 minutes to obtain a regenerated LLNO-R sheet.

[0052] The LLNO-R sheet obtained in this example was scanned and tested using an X-ray diffractometer and an electrochemical workstation to obtain the XRD pattern of the LLNO-R sheet. Figure 4 As shown, the ionic conductivity was measured to be 5.3*10 -4 S / cm.

[0053] Figure 4 It can be seen that the diffraction peaks of LLNO-R are consistent with the PDF#45-0109 standard card, and there are no impurity peaks, which proves that the crystal structure of the regenerated material is good.

[0054] Comparative Example 3 Garnet-type oxide solid electrolyte Li is obtained by disassembling waste solid-state batteries 6.4 La3Nb2O 12 (LLNO); LLNO was polished with 1000-grit sandpaper until the surface was smooth and free of contaminants to obtain LLNO-S. The LLNO-S sheet obtained in this comparative example was scanned and tested using an X-ray diffractometer and an electrochemical workstation, and the XRD pattern of the LLNO-S sheet was as follows: Figure 5 As shown, the ionic conductivity was measured to be 2.2*10 -4 S / cm.

[0055] from Figure 5As can be seen from the image, the background value of LLNO-S after polishing alone deviates significantly, and there are obvious impurity peaks. However, the basic crystal structure is still maintained, indicating that some LLNO crystal particles have changed after use. However, it can also be seen that the main diffraction peaks of LLNO-S are generally consistent with those of the PDF#45-0109 standard card, indicating that it can be recycled through subsequent processing.

[0056] The ionic conductivity of LLNO-S in this comparative example is relatively low, indicating that defects such as lithium dendrites or microcracks may have appeared in the waste LLNO-S, resulting in a decrease in its ionic conductivity.

[0057] Compared with Comparative Example 3, Example 2 shows that after further treatment using the recycling process, the crystal structure of Example 2 is corrected and the defects are removed. Therefore, the ionic conductivity of the LLNO-R in Example 2 is significantly improved compared with that in Comparative Example 3.

[0058] Example 3 1) Dismantle the waste solid-state battery to obtain garnet-type oxide solid electrolyte Li 6.4 La3Nb2O 12 (LLNO); polish the LLNO with 1000-grit sandpaper until the surface is smooth and free of contaminants, thereby obtaining polished LLNO. Grind the polished LLNO in a mortar for 10 minutes to obtain LLNO powder.

[0059] 2) The LLNO powder was heated to 300°C at a rate of 8°C / min, kept at that temperature for 30 min, and then cooled to room temperature to obtain annealed LLNO powder.

[0060] 3) The annealed LLNO powder, polyvinylidene fluoride, lithium perchlorate, and NN-dimethylformamide were mixed in a mass ratio of 60:1.5:7.5:12.5 and ground for 20 minutes to obtain a mixture. The mixture was placed in a cylindrical mold with a diameter of 15 mm and a pressure of 150 bar was applied. The mixture and the pressurized mold were placed in a muffle furnace under an argon atmosphere at 130°C for 40 minutes to obtain a regenerated LLNO-R sheet.

[0061] The LLNO-R sheet obtained in this example was tested using an electrochemical workstation, and the ionic conductivity of the LLNO-R sheet was found to be 5.4*10 -4 S / cm.

[0062] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for recovering and regenerating waste garnet-type oxide solid electrolyte, characterized in that: The steps include: (1) dismantling waste solid-state batteries to obtain waste garnet-type oxide solid electrolytes; polishing the surface of the waste garnet-type oxide solid electrolytes to obtain polished garnet-type oxide solid electrolytes; (2) crushing the polished garnet oxide solid electrolyte into powder to obtain solid electrolyte powder; annealing the solid electrolyte powder under an inert atmosphere to obtain annealed solid electrolyte powder; (3) The annealed solid electrolyte powder, binder, lithium supplement and organic solvent are uniformly mixed to obtain a mixture; the mixture is placed in a mold and pressurized; the mold containing the mixture and pressurized is placed in a sintering furnace and heat-treated under an inert atmosphere to obtain a regenerated garnet-type oxide solid electrolyte sheet.

2. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In the step (1), the chemical formula of the waste garnet-type oxide solid electrolyte is Li x A2(LaO4)3, wherein A is one or more metals selected from Al, Fe, Ga, Zr, Ta, and Sc, and x>0.

3. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In the step (2), the crushing is performed by grinding, and the crushing time is 10 to 40 minutes.

4. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In the step (2), the heating rate of the annealing treatment is 5-10°C / min; the temperature of the annealing treatment is 160-300°C; and the holding time of the annealing treatment is 30-120min.

5. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 4, characterized in that: The heating rate of the annealing treatment is 5-8°C / min; the temperature of the annealing treatment is 160-250°C; and the holding time of the annealing treatment is 40-100 minutes.

6. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In step (3), the binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, and polypropylene carbonate; the lithium supplement is one or more of lithium carbonate, lithium hydroxide, and lithium perchlorate; and the organic solvent is one or more of anhydrous acetonitrile, N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

7. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In the step (3), the mass ratio of the solid electrolyte powder, the binder, the lithium supplement agent and the organic solvent is 60:0.5~2:1~10:10~20.

8. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 7, characterized in that: The mass ratio of solid electrolyte powder, binder, lithium supplement and organic solvent is 60:1~2:5~10:10~15.

9. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 1, characterized in that: In the step (3), the pressurized pressure is 50-200 bar, the heat treatment temperature is 100-150° C., and the heat treatment holding time is 30-120 min.

10. The method for recycling and regenerating waste garnet-type oxide solid electrolyte according to claim 9, characterized in that: The pressurized pressure is 80~150bar, the heat treatment temperature is 100~130℃, and the heat treatment holding time is 60~120min.

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