Ga-LLZO Solid Electrolyte and Method for Suppressing Abnormal Grain Growth thereof

Abstract

The present invention provides a Ga-LLZO solid electrolyte and a method for suppressing abnormal grain growth thereof, relating to the technical field of lithium batteries. The method for suppressing abnormal grain growth of the Ga-LLZO solid electrolyte comprises the following steps: obtaining LLYZO powder through Li2CO3, La2O3, ZrO2 and Yb2O3; obtaining Ga-LLZO powder through Li2CO3, La2O3, ZrO2 and Ga2O3; mixing the LLYZO powder and the Ga-LLZO powder, ball-milling and drying to obtain a composite masterbatch; pressure-forming the composite masterbatch into a laminate structure, and after calcination treatment, cooling to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains, and there is no phenomenon of abnormal grain growth.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and more particularly, to a Ga-LLZO solid electrolyte and a method for suppressing abnormal grain growth thereof. Background Art

[0002] Traditional lithium-ion batteries are approaching their energy limits. Due to the use of liquid organic electrolytes, there are risks of explosion and combustion, and their safety in related application fields of power batteries has also been questioned. All-solid-state lithium batteries using solid electrolytes and lithium metal anodes have higher energy density and higher safety, and replacing traditional lithium-ion batteries has become the future development trend.

[0003] As the core component of all-solid-state lithium batteries, solid electrolytes need to have excellent comprehensive performance. In recent years, ceramic electrolytes with garnet-type structures have good chemical stability and ionic conductivity, making them outstanding among various types of electrolytes. Element doping is an important modification method for garnet-type LLZO electrolytes. Among them, Ga-doped LLZO electrolytes exhibit the highest lithium-ion conductivity. However, there is a problem of abnormal grain growth, resulting in the fragility of Ga-LLZO electrolytes, which limits their application in lithium batteries. Summary of the Invention

[0004] The problem solved by the present invention is that in the prior art, Ga-doped LLZO electrolytes have high lithium-ion conductivity, but the grains are abnormally large and the grain quality is poor, which limits their application in lithium batteries.

[0005] To solve the above problems, the present invention provides a method for suppressing abnormal grain growth of Ga-LLZO solid electrolytes, including the following steps:

[0006] Step S1, weighing Li2CO3, La2O3, ZrO2 and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 in molar ratio, and performing primary ball milling, drying, then obtaining a first premixed powder. After calcining, secondary ball milling and drying the first premixed powder, LLYZO powder is obtained;

[0007] Step S2, weighing Li2CO3, La2O3, ZrO2 and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12 in molar ratio, and performing primary ball milling, drying, then obtaining a second premixed powder. After calcining, secondary ball milling and drying the second premixed powder, Ga-LLZO powder is obtained;

[0008] Step S3: Mix the LLYZO powder and the Ga-LLZO powder, ball-mill and dry them to obtain a composite master powder.

[0009] Step S4: Press the composite master powder into a laminate structure, and after calcination treatment, cool it to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains.

[0010] Preferably, in step S3, the mass fraction of the LLYZO powder in the composite master powder is 40%-50%.

[0011] Preferably, in steps S1 and S2, the process of the first ball-milling includes: adding a grinding aid into a ball mill and ball-milling at a speed of 60-80 r / min for 22-26 h.

[0012] Preferably, the grinding aid includes isopropanol and zirconia.

[0013] Preferably, the process of the second ball-milling in steps S1 and S2 and the ball-milling in step S3 includes: planetary ball-milling in a ball mill tank at a speed of 450-550 r / min for 10-14 h.

[0014] Preferably, in steps S1, S2 and S3, the process of drying includes: drying at a temperature of 55-65 °C for 5-7 hours.

[0015] Preferably, in step S1, the process of calcination includes: calcining the first premixed powder at 850-950 °C for 5-7 hours, then raising the temperature to 1220-1240 °C and holding for 0.4-0.6 h, and then cooling to room temperature at a speed of 4-5 °C / min.

[0016] Preferably, in step S4, pressing the composite master powder into a laminate structure includes: pressing the composite master powder into a laminate structure with a diameter of 12-14 mm under a pressure of 180-220 MPa.

[0017] Preferably, in step S4, the process of calcination treatment includes: calcining at a temperature of 980-1020 °C for 10-14 h, calcining at a temperature of 1030-1070 °C for 16-120 h, and calcining at a temperature of 1090-1130 °C for 22-26 h.

[0018] The advantage of the method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to the present invention compared with the prior art is that by compounding LLYZO powder and the Ga-LLZO powder, a second phase LiYbO2 can be introduced to inhibit the migration of grain boundaries during the firing process of the Ga-LLZO solid electrolyte, thereby suppressing the growth of grains. Finally, a Ga-LLZO solid electrolyte with fine and uniformly distributed grains is obtained to improve its mechanical properties, and the preparation methods of the LLYZO powder and the Ga-LLZO powder are simple.

[0019] To solve the above technical problems, the present invention also provides a Ga-LLZO solid electrolyte prepared by the method for suppressing abnormal grain growth of the Ga-LLZO solid electrolyte.

[0020] The Ga-LLZO solid electrolyte according to the present invention has finer grains and higher strength, which is helpful for the practical application of the Ga-LLZO solid electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flowchart of the method for suppressing abnormal grain growth of the Ga-LLZO solid electrolyte in the embodiment of the present invention;

[0022] Figure 2 It is an XRD pattern of the Ga-LLZO solid electrolyte in the embodiment of the present invention;

[0023] Figure 3 It is a scanning electron microscope photograph of the fracture surface of the Ga-LLZO ceramic electrolyte in the comparative example of the present invention;

[0024] Figure 4 It is a scanning electron microscope photograph of the fracture surface of the Ga-LLZO solid electrolyte in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions in the embodiments of the present application will be clearly and elaborately described below with reference to the drawings.

[0026] In the description of the embodiments of the present application, the description of the term "some embodiments" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0027] As Figure 1 shown, the embodiment of the present invention provides a method for suppressing abnormal grain growth of a Ga-LLZO solid electrolyte, which is characterized by including the following steps:

[0028] Step S1, weigh Li2CO3, La2O3, ZrO2 and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 in a molar ratio, conduct primary ball milling and drying, to obtain a first premixed powder, and after calcining, secondary ball milling and drying the first premixed powder, obtain LLYZO powder;

[0029] Step S2, weigh Li2CO3, La2O3, ZrO2 and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12 in a molar ratio, conduct primary ball milling and drying, to obtain a second premixed powder, and after calcining, secondary ball milling and drying the second premixed powder, obtain Ga-LLZO powder;

[0030] Step S3, mix the LLYZO powder and the Ga-LLZO powder and conduct ball milling and drying to obtain a composite master powder;

[0031] Step S4, press the composite master powder into a laminated structure, and after calcination treatment, cool to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains.

[0032] In this embodiment, when preparing the electrolyte, to make up for the loss of Li, generally Li is made slightly excessive. Specifically, in this embodiment, Li2CO3 is excessive by 15 wt.%, which can not only make up for the loss of Li, but also save raw materials.

[0033] In some preferred embodiments, in Step S3, the mass fraction of the LLYZO powder in the composite master powder is 40%-50%, which neither affects the conductivity of the lithium battery nor can inhibit the abnormal growth of grains in the Ga-LLZO solid electrolyte during the firing process.

[0034] In some preferred embodiments, in Step S1 and Step S2, the process of the primary ball milling includes: adding a grinding aid into a ball mill and ball milling at a speed of 60-80 r / min for 22-26 h. Thereby, the raw materials are evenly mixed, and the addition of the grinding aid can prevent particle agglomeration, improve the fluidity of the material, thereby improving the ball milling efficiency and shortening the grinding time.

[0035] In some preferred embodiments, the grinding aid includes isopropyl alcohol and zirconia. The materials are easily available.

[0036] In some preferred embodiments, the process of the secondary ball milling in steps S1 and S2 and the ball milling in step S3 includes: in a ball milling tank, planetary ball milling at a speed of 450 - 550 r / min for 10 - 14 h to make the mixture more uniform. Thus, the mixture is more uniform and delicate.

[0037] In some preferred embodiments, in steps S1, S2, and S3, the process of the drying includes: drying at a temperature of 55 - 65 °C for 5 - 7 hours. Thus, the isopropanol in the grinding aid completely volatilizes.

[0038] In some preferred embodiments, in step S1, the process of the calcination includes: calcining the first premixed powder at 850 - 950 °C for 5 - 7 hours, then raising the temperature to 1220 - 1240 °C and holding for 0.4 - 0.6 h, and then cooling to room temperature at a rate of 4 - 5 °C / min. In step S2, the process of the calcination only requires calcining the first premixed powder at 850 - 950 °C for 5 - 7 hours. This is because, during the sintering process of Ga-LLZO powder, Ga + will enter the Li site in the [La3Zr2O 12 7- skeleton, and after sintering into a pure phase, it can reduce the sintering temperature, so it can be calcined at 850 - 950 °C. While during the sintering process of LLYZO powder, Yb 3+ will enter the La site or Zr site in the [La3Zr2O 12 7- skeleton, and after sintering into a pure phase, its effect on reducing the sintering temperature is not obvious. Therefore, it needs to be calcined at 850 - 950 °C for 5 - 7 hours, then raise the temperature to 1220 - 1240 °C and hold for 0.4 - 0.6 h to obtain a pure phase.

[0039] In some preferred embodiments, in step S4, forming the composite masterbatch powder into a laminate structure includes: forming the composite masterbatch powder into a laminate structure with a diameter of 12 - 14 mm under a pressure of 180 - 220 MPa. The forming effect is good.

[0040] In some preferred embodiments, in step S4, the process of the calcination treatment includes: calcining at a temperature of 980 - 1020 °C for 10 h - 14 h, calcining at a temperature of 1030 - 1070 °C for 16 h - 120 h, and calcining at a temperature of 1090 - 1130 °C for 22 h - 26 h.

[0041] ​​In this embodiment, by compounding LLYZO powder and the Ga-LLZO powder, a second phase LiYbO2 can be introduced to inhibit the migration of grain boundaries during the firing process of the Ga-LLZO solid electrolyte, thereby inhibiting the growth of grains. Ultimately, a Ga-LLZO solid electrolyte with fine and uniformly distributed grains is obtained to improve its mechanical properties, and the preparation methods of the LLYZO powder and the Ga-LLZO powder are simple.

[0042] Another embodiment of the present invention also provides a Ga-LLZO solid electrolyte prepared by the method for inhibiting abnormal grain growth of the Ga-LLZO solid electrolyte described above.

[0043] The Ga-LLZO solid electrolyte described in this embodiment has finer grains and service strength, which is helpful for the practical application of the Ga-LLZO solid electrolyte.

[0044] Example 1

[0045] This embodiment provides a method for inhibiting abnormal grain growth of a Ga-LLZO solid electrolyte, including the following steps:

[0046] Step 1, Weigh Li2CO3, La2O3, ZrO2 and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 in a molar ratio. To compensate for the lithium loss during the sintering process of the electrolyte, Li2CO3 is in an excess of 15 wt.%. Isopropyl alcohol and zirconia grinding balls are added to the raw materials for primary ball milling. The ball mill mills at a speed of 70 r / min for 24 h to obtain a first mixed slurry. After the first mixed slurry is dried in an oven at 60 °C, a first premixed powder is obtained. The first premixed powder is calcined at 900 °C for 6 hours, then heated to 1230 °C and held for 0.5 h, and then cooled to room temperature at a rate of 5 °C / min to obtain LLYZO coarse powder. The LLYZO coarse powder, isopropyl alcohol and agate grinding balls are placed in a ball mill jar and planetary ball milled at a speed of 500 r / min for 12 h, and then dried at 60 °C to obtain LLYZO powder with fine and uniform particle size;

[0047] Step 2, Weigh Li2CO3, La2O3, ZrO2 and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12Weigh by molar ratio. To compensate for the lithium loss during the sintering of the electrolyte, 15 wt.% of Li2CO3 is in excess. Isopropyl alcohol and zirconia grinding balls are added to the raw materials for primary ball milling. The ball mill mills at a speed of 70 r / min for 24 h to obtain a second mixed slurry. After drying the second mixed slurry in an oven at 60 °C, a second premixed powder is obtained. The second premixed powder is calcined at 900 °C for 6 hours and cooled to room temperature to obtain Ga-LLZO coarse powder. The Ga-LLZO coarse powder, isopropyl alcohol, and agate grinding balls are placed in a ball mill jar and planetary ball milled at a speed of 500 r / min for 12 h, and then dried at 60 °C to obtain Ga-LLZO powder with fine and uniform particle size;

[0048] Step 3: Mix the LLYZO powder and the Ga-LLZO powder to obtain a premixed powder. The premixed powder, isopropyl alcohol, and agate grinding balls are placed in a ball mill jar and planetary ball milled at a speed of 500 r / min for 12 h, and then dried at 60 °C to obtain a composite master powder with fine and uniformly mixed particle size, where the mass fraction of the LLYZO powder in the composite master powder is 45%;

[0049] Step 4: Press the composite master powder into a thin disc with a diameter of 13 mm under a pressure of 200 MPa, and then calcine it in a muffle furnace and naturally cool it to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains.

[0050] The XRD pattern and the fracture surface scanning electron microscope photograph of the Ga-LLZO solid electrolyte obtained in this example are as Figure 2 and Figure 4 shown. It can be seen from Figure 2 that the main phase of the Ga-LLZO solid electrolyte ceramic is c-LLZO, and there is a second phase of LiYbO2; it can be seen from Figure 4 that the ceramic grains are fine and uniform and the grain combination is relatively tight, the average grain diameter is 2 - 5 microns, there is no abnormal grain growth phenomenon, and the fracture mode is a composite fracture of transgranular and intergranular fractures, indicating that the ceramic has good mechanical properties.

[0051] Comparative Example

[0052] The difference between the preparation method of a Ga-LLZO solid electrolyte provided in this example and that in Example 1 is only that the raw material is only Ga-LLZO powder, and it includes the following steps:

[0053] Step 1: Mix Li2CO3, La2O3, ZrO2, and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12Weighing by molar ratio, to compensate for the lithium loss during the sintering of the electrolyte, 15 wt.% of Li2CO3 is in excess. Isopropanol and zirconia grinding balls are added to the raw materials for primary ball milling. The ball mill mills at a speed of 70 r / min for 24 h to obtain a second mixed slurry. After drying the second mixed slurry in an oven at 60 °C, a second premixed powder is obtained. The second premixed powder is calcined at 900 °C for 6 hours and cooled to room temperature to obtain Ga-LLZO coarse powder. The Ga-LLZO coarse powder, isopropanol and agate grinding balls are placed in a ball mill jar and planetary ball milled at a speed of 500 r / min for 12 h and then dried at 60 °C to obtain Ga-LLZO powder with fine and uniform particle size;

[0054] Step 2, press the Ga-LLZO powder into a thin disc with a diameter of 13 mm under a pressure of 200 MPa, then calcine it in a muffle furnace and naturally cool it to room temperature to obtain a Ga-LLZO solid electrolyte.

[0055] The fracture scanning electron microscope photograph of the Ga-LLZO solid electrolyte obtained in this comparative example is as Figure 3 shown, from Figure 3 which it can be seen that the grains are millimeter-sized, and the grains are loose and porous, showing the phenomenon of abnormal growth.

[0056] Example 2

[0057] This example provides a method for suppressing abnormal grain growth of a Ga-LLZO solid electrolyte, including the following steps:

[0058] Step 1, weigh Li2CO3, La2O3, ZrO2 and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 by molar ratio. To compensate for the lithium loss during the sintering of the electrolyte, 15 wt.% of Li2CO3 is in excess. Isopropanol and zirconia grinding balls are added to the raw materials for primary ball milling. The ball mill mills at a speed of 60 r / min for 26 h to obtain a first mixed slurry. After drying the first mixed slurry in an oven at 55 °C, a first premixed powder is obtained. The first premixed powder is calcined at 850 °C for 7 hours, then heated to 1220 °C and held for 0.6 h, and then cooled to room temperature at a rate of 4 °C / min to obtain LLYZO coarse powder. The LLYZO coarse powder, isopropanol and agate grinding balls are placed in a ball mill jar and planetary ball milled at a speed of 450 r / min for 14 h and then dried at 55 °C to obtain LLYZO powder with fine and uniform particle size;

[0059] Step 2, weigh Li2CO3, La2O3, ZrO2 and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25La3Zr2O 12 Weigh according to the molar ratio. To compensate for the lithium loss during the sintering process of the electrolyte, Li2CO3 is in an excess of 15 wt.%. Add isopropanol and zirconia grinding balls to the raw materials for primary ball milling. The ball mill mills at a speed of 60 r / min for 26 h to obtain a second mixed slurry. After drying the second mixed slurry in an oven at 55 °C, a second premixed powder is obtained. The second premixed powder is calcined at 850 °C for 7 h and then cooled to room temperature to obtain Ga-LLZO coarse powder. Place the Ga-LLZO coarse powder, isopropanol, and agate grinding balls in a ball mill jar and perform planetary ball milling at a speed of 450 r / min for 14 h, and then dry at 55 °C to obtain Ga-LLZO powder with fine and uniform particle size;

[0060] Step 3: Mix the LLYZO powder and the Ga-LLZO powder to obtain a premixed powder. Place the premixed powder, isopropanol, and agate grinding balls in a ball mill jar and perform planetary ball milling at a speed of 450 r / min for 14 h, and then dry at 55 °C to obtain a composite master powder with fine and uniform particle size. The mass fraction of the LLYZO powder in the composite master powder is 40%;

[0061] Step 4: Press the composite master powder into a thin disc with a diameter of 12 mm under a pressure of 180 MPa, and then perform calcination treatment in a muffle furnace and naturally cool to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains.

[0062] Example 3

[0063] This example provides a method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte, including the following steps:

[0064] Step 1: Weigh Li2CO3, La2O3, ZrO2, and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 Weigh according to the molar ratio. To compensate for the lithium loss during the sintering process of the electrolyte, Li2CO3 is in an excess of 15 wt.%. Add isopropanol and zirconia grinding balls to the raw materials for primary ball milling. The ball mill mills at a speed of 80 r / min for 22 h to obtain a first mixed slurry. After drying the first mixed slurry in an oven at 65 °C, a first premixed powder is obtained. The first premixed powder is calcined at 950 °C for 5 h, then heated to 1240 °C and held for 0.4 h, and then cooled to room temperature at a rate of 5 °C / min to obtain LLYZO coarse powder. Place the LLYZO coarse powder, isopropanol, and agate grinding balls in a ball mill jar and perform planetary ball milling at a speed of 550 r / min for 10 h, and then dry at 65 °C to obtain LLYZO powder with fine and uniform particle size;

[0065] Step 2: Weigh Li2CO3, La2O3, ZrO2 and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12 in a molar ratio. To compensate for the lithium loss during the sintering process of the electrolyte, 15 wt.% of Li2CO3 is in excess. Add isopropanol and zirconia grinding balls to the raw materials for primary ball milling. The ball mill mills at a speed of 80 r / min for 22 h to obtain a second mixed slurry. After drying the second mixed slurry in an oven at 65 °C, a second premixed powder is obtained. Calcinate the second premixed powder at 950 °C for 5 h, and cool it to room temperature to obtain Ga-LLZO coarse powder. Place the Ga-LLZO coarse powder, isopropanol and agate grinding balls in a ball mill tank, and perform planetary ball milling at a speed of 550 r / min for 10 h. After drying at 65 °C, Ga-LLZO powder with fine and uniform particle size is obtained;

[0066] Step 3: Mix the LLYZO powder and the Ga-LLZO powder to obtain a premixed powder. Place the premixed powder, isopropanol and agate grinding balls in a ball mill tank, and perform planetary ball milling at a speed of 550 r / min for 10 h. After drying at 65 °C, a composite master powder with fine and uniform particle size is obtained, where the mass fraction of the LLYZO powder in the composite master powder is 50%;

[0067] Step 4: Press the composite master powder into a thin disc with a diameter of 14 mm under a pressure of 220 MPa, and then calcinate it in a muffle furnace and naturally cool it to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains.

[0068] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte grains, characterized in that, It includes the following steps: Step S1, weigh Li2CO3, La2O3, ZrO2 and Yb2O3 according to the chemical formula Li7La 2.7 Yb 0.3 Zr2O 12 in a molar ratio, perform ball milling and drying once to obtain a first premixed powder, and after calcination, secondary ball milling and drying of the first premixed powder, obtain LLYZO powder. The calcination process includes: calcining the first premixed powder at 850-950 °C for 5-7 hours, then raising the temperature to 1220-1240 °C and holding for 0.4-0.6 h, and then cooling to room temperature at a rate of 4-5 °C / min; Step S2: Weigh Li2CO3, La2O3, ZrO2, and Ga2O3 according to the chemical formula Li 6.25 Ga 0.25 La3Zr2O 12 in molar ratio, and after performing primary ball milling and drying, obtain a second premixed powder. After calcining, secondary ball milling, and drying the second premixed powder, Ga-LLZO powder is obtained; Step S3: Mix the LLYZO powder and the Ga-LLZO powder, and ball-mill and dry them to obtain a composite master powder, where the mass fraction of the LLYZO powder in the composite master powder is 40%-50%; Step S4: Press the composite master powder into a laminate structure, and after calcination treatment, cool it to room temperature to obtain a Ga-LLZO solid electrolyte with fine and uniform grains. The process of the calcination treatment includes: calcining at a temperature of 980-1020°C for 10h-14h, calcining at a temperature of 1030-1070°C for 16h-120h, and calcining at a temperature of 1090-1130°C for 22h-26h.

2. The method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to claim 1, wherein In Step S1 and Step S2, the process of the primary ball-milling includes: adding a grinding aid into a ball mill and ball-milling at a speed of 60-80r / min for 22-26h.

3. The method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to claim 2, characterized in that The grinding aid includes isopropyl alcohol and zirconia.

4. The method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to claim 1, wherein The process of the secondary ball-milling in Step S1 and Step S2 and the ball-milling in Step S3 includes: planetary ball-milling in a ball mill tank at a speed of 450-550r / min for 10-14h.

5. The method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to claim 1, wherein In Step S1, Step S2 and Step S3, the process of the drying includes: drying at a temperature of 55-65°C for 5-7 hours.

6. The method for suppressing abnormal grain growth of Ga-LLZO solid electrolyte according to claim 1, characterized in that In Step S4, pressing the composite master powder into a laminate structure includes: pressing the composite master powder into a laminate structure with a diameter of 12-14mm under a pressure of 180-220MPa.

7. A Ga-LLZO solid electrolyte, characterized in that, It is prepared by the method for suppressing abnormal grain growth of the Ga-LLZO solid electrolyte according to any one of claims 1-6.

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