Preparation method of solid-state battery cell, solid-state battery cell and solid-state battery

Abstract

The invention discloses a preparation method of a solid-state battery cell, the solid-state battery cell and a solid-state battery. The preparation method of the solid-state battery cell comprises the following steps: preparing LISICON type solid-state electrolyte powder; carrying out molding treatment on a first mixture containing LISICON type solid electrolyte powder and a plasticizing solution to prepare a primary solid electrolyte layer; and coating one side of the primary solid electrolyte layer with a second mixture containing LISICON type solid electrolyte powder and a positive electrode material, and sintering to obtain a solid electrolyte layer and a positive electrode layer which are of an integrated structure. According to the solid-state battery cell prepared by the method, the interface impedance between the solid-state electrolyte and the positive electrode can be effectively reduced, so that the electrical property of the solid-state battery cell is improved.

Description

Technical Field

[0001] The present invention relates to a preparation method of a solid-state battery core, a solid-state battery core and a solid-state battery. Background Art

[0002] The core functional component of a solid-state battery is a series / parallel array of solid-state cells, which use solid electrolytes instead of liquid electrolytes. Compared to the liquid batteries commonly used in current vehicles, solid-state batteries can avoid problems such as battery combustion, explosion, and leakage. Furthermore, the high energy density and safety advantages of solid-state cells can also help improve vehicle range. Therefore, solid-state batteries have great potential for application in electric vehicles.

[0003] At present, solid-state battery cells prepare solid electrolytes, positive electrodes and negative electrodes separately, and then sequentially attach the positive and negative electrodes to the solid electrolytes. That is, there is an obvious interface between the solid electrolyte and the electrode sheets (especially the positive electrode sheets). The interface between the solid electrolyte and the positive electrode sheet will more significantly affect the performance of the solid-state battery cell. Therefore, the large interface impedance between the solid electrolyte and the positive electrode in existing solid-state battery cells means that there is still a lot of room for improvement in the electrical performance of the solid-state battery cells. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a solid-state battery cell, a solid-state battery cell and a solid-state battery. The preparation method can prepare a positive electrode and a solid-state electrolyte as an integrated structure, avoid the appearance of an obvious interface between the positive electrode and the solid-state electrolyte, and effectively reduce the interface impedance between the positive electrode and the solid-state electrolyte, so as to improve the electrical performance of the solid-state battery cell.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a method for preparing a solid-state battery cell, comprising:

[0007] Step 1: preparing LISICON solid electrolyte powder;

[0008] Step 2: forming the first mixture comprising the LISICON solid electrolyte powder and the plasticizing solution to form a primary solid electrolyte layer;

[0009] Step 3: coating a second mixture comprising the LISICON solid electrolyte powder and a cathode material on one side of the primary solid electrolyte layer and sintering the mixture to obtain a solid electrolyte layer and a cathode layer of an integrated structure.

[0010] Optionally, step 1 includes:

[0011] Step 11: Mixing LISICON solid electrolyte materials according to a stoichiometric ratio, adding ball milling media to the mixture, and ball milling for 2 hours to 24 hours;

[0012] Step 12: vacuum drying / air drying the ball-milled mixture at 10° C. to 100° C. for 2 h to 24 h, and pre-sintering the dried mixture in an air atmosphere at 600° C. to 1200° C. for 5 h to 20 h;

[0013] Step 13: ball-mill the pre-sintered material again for 2 h to 12 h, and vacuum-dry at 10° C. to 100° C. for 2 h to 24 h to obtain LISICON solid electrolyte powder.

[0014] Optionally, the LISICON solid electrolyte material includes at least the following materials:

[0015] Lithium carbonate (Li2CO3), silicon dioxide (SiO2), zirconium dioxide (ZrO2), diammonium hydrogen phosphate ((NH4)2HPO4), scandium oxide (Sc2O3) and germanium dioxide (GeO2).

[0016] Optionally, the LISICON-type solid electrolyte material includes Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3 and GeO2 in a molar ratio of: (2-10): (1-10): (1-10): (1:8): (0.1-1): (0.1-1).

[0017] Optionally, step 2 includes: step 21, pressing a third mixture formed by LISICON solid electrolyte powder and plasticizing solution to form a first primary solid electrolyte layer.

[0018] Optionally, step 2 further includes:

[0019] Step 22: applying a fourth mixture formed by LISICON solid electrolyte powder, a volatile material, and a plasticizing solution to one main surface of the first primary solid electrolyte layer to form a second primary solid electrolyte layer;

[0020] Step 23: First, simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer at a temperature of 60°C to 120°C for 0.5h to 2h, then raise the temperature to 400°C to 600°C, continue to simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 1h to 4h, further raise the temperature to 1000°C to 1300°C, continue to simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 10h to 18h, to form a solid electrolyte layer with a porous structure on one main surface.

[0021] Optionally, step 3 includes: coating a second mixture comprising the LISICON solid electrolyte powder and a positive electrode material on one side of the solid electrolyte layer having a porous structure, and sintering at 600° C. to 900° C. for 6 h to 16 h.

[0022] Optionally, the mass fraction of the volatile material in the fourth mixture is 0.5% to 4%.

[0023] Optionally, in the solid electrolyte layer having a porous structure, the porosity of the porous structure is 1% to 15%; and the pore diameter is 0.1 μm to 5 μm.

[0024] Optionally, the thickness of the solid electrolyte layer is 5 μm to 30 μm.

[0025] Optionally, step 3 includes:

[0026] Step 31: applying a second mixture comprising the LISICON solid electrolyte powder and a cathode material to one side of the first primary solid electrolyte layer to form a primary cathode layer;

[0027] Step 32: Simultaneously sintering the first primary solid electrolyte layer and the primary positive electrode layer to obtain a solid electrolyte layer and a positive electrode layer of an integrated structure.

[0028] Optionally, the method for preparing a solid-state battery cell may further include: step 4, providing a negative electrode layer on the main surface of the solid electrolyte layer away from the positive electrode layer.

[0029] In the second aspect, an embodiment of the present invention provides a solid-state battery cell, which is prepared by the preparation method provided by the above-mentioned first aspect embodiment or other embodiments related to the first aspect embodiment, and the solid-state battery cell includes: a solid electrolyte layer and a positive electrode layer that is an integrated structure with the solid electrolyte layer.

[0030] In a third aspect, an embodiment of the present invention provides a solid-state battery, which may include: the solid-state battery cell provided in the embodiment of the second aspect above.

[0031] In a fourth aspect, an embodiment of the present invention provides a vehicle, which may include: the solid-state battery provided in the embodiment of the third aspect above.

[0032] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects:

[0033] The technical solution provided by the embodiment of the present invention is to form a primary solid electrolyte layer by molding a first mixture containing LISICON solid electrolyte powder and a plasticizer solution, and then apply a second mixture containing LISICON solid electrolyte powder and a positive electrode material to one side of the primary solid electrolyte layer and sinter. During the sintering process, on the one hand, a solid-phase reaction occurs between the LISICON solid electrolyte powder in the second mixture and the LISICON solid electrolyte powder on the surface of the primary solid electrolyte layer and the positive electrode material, so that the interface between the LISICON solid electrolyte powder and the positive electrode material can be eliminated; on the other hand, the primary solid electrolyte layer and the LISICON solid electrolyte powder in the second mixture interact with each other through hydrogen bonds or intermolecular van der Waals forces to form a whole, avoiding the appearance of a clear interface between the positive electrode and the solid electrolyte, effectively reducing the interfacial impedance between the positive electrode and the solid electrolyte, and thus improving the electrical performance of the solid-state battery cell.

[0034] In addition, the solid electrolyte layer and positive electrode layer of the integrated structure prepared by the preparation method provided in the embodiment of the present invention reduce the interface impedance between the positive electrode and the solid electrolyte, and at the same time can improve the capacity density of the solid electrolyte layer, thereby effectively improving the rate performance of the solid-state battery cell.

[0035] In addition, compared with the existing method of preparing the solid electrolyte layer, positive electrode sheet and negative electrode sheet separately, the technical solution provided by the embodiment of the present invention is to simultaneously obtain the solid electrolyte layer and positive electrode layer of an integrated structure, omitting the separate preparation process of the positive electrode sheet and the assembly process between the positive electrode sheet and the solid electrolyte layer, effectively simplifying the solid-state battery cell preparation process and helping to reduce the manufacturing cost of the solid-state battery cell.

[0036] Furthermore, compared with liquid batteries, the solid electrolyte layer and positive electrode layer of the integrated structure can avoid problems such as battery combustion, explosion, and leakage, and has the advantage of higher safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the structural changes of solid-state batteries prepared using existing technology;

[0038] Figure 2 1 is a schematic diagram of the main process of the method for preparing a solid-state battery cell according to an embodiment of the present invention;

[0039] Figure 3 1 is a schematic diagram of the main process of a first specific method for preparing a solid-state battery cell provided by an embodiment of the present invention;

[0040] Figure 4Schematic diagram of structural changes corresponding to each step of the first specific preparation method provided in an embodiment of the present invention;

[0041] Figure 5 1 is a schematic diagram of the main process of a second specific method for preparing a solid-state battery cell provided by an embodiment of the present invention;

[0042] Figure 6 It is a schematic diagram of the structural changes corresponding to each step of the second specific preparation method provided according to an embodiment of the present invention.

[0043] Reference numerals:

[0044] 10-solid electrolyte layer; 11-solid electrolyte powder; 12-complete first solid electrolyte layer; 12'-first primary solid electrolyte layer; 13-porous second solid electrolyte layer; 13'-second primary solid electrolyte layer; 20-positive electrode sheet; 20'-positive electrode layer; 20"-primary positive electrode layer; 30-negative electrode sheet; 30'-negative electrode layer. DETAILED DESCRIPTION

[0045] For example, Figure 1 As shown, in the prior art, the solid electrolyte layer 10, the positive electrode sheet 20 and the negative electrode sheet 30 are prepared separately, and then the solid electrolyte layer 10, the positive electrode sheet 20 and the negative electrode sheet 30 are assembled. Figure 1 As shown, the positive electrode sheet 20 and the negative electrode sheet 30 are respectively assembled on both sides of the solid electrolyte layer 10. On the one hand, in the prior art, it is necessary to prepare the solid electrolyte layer 10, the positive electrode sheet 20 and the negative electrode sheet 30 separately as well as the assembly process, which makes the solid-state battery preparation process more complicated. On the other hand, there will be an obvious interface between the assembled solid electrolyte layer 10 and the positive electrode sheet 20. The existence of this interface will significantly increase the interfacial impedance between the solid electrolyte and the positive electrode in the solid-state battery cell. The existence of this interfacial impedance will significantly reduce the electrical performance of the solid-state battery cell. Studies have found that the interface between the negative electrode sheet 30 and the solid electrolyte layer 10 does not significantly affect the electrical performance of the solid-state battery cell. Therefore, the technical solution provided in the embodiment of the present invention is mainly to solve the problem of the existence of an interface and a high interfacial impedance between the solid electrolyte 30 and the positive electrode sheet 20.

[0046] Specifically, Figure 2 The main flow chart of the method for preparing a solid-state battery cell provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the preparation method of the solid-state battery cell may include the following steps:

[0047] Step S201: preparing electrolyte powder, preparing LISICON type solid electrolyte powder.

[0048] The LISICON type solid electrolyte powder is formed by mixing a variety of solid electrolyte materials used to prepare batteries. The LISICON type solid electrolyte powder generally contains compounds that can provide lithium ions, such as Li2CO3, Li2SO4, Li3Fe2(PO4)3 or LiMnPO4 and other inorganic lithium-containing compounds (in addition, the lithium ion compound can also be an organic lithium-containing compound commonly used in the prior art), silicon ion compounds such as SiO2 and oxide electrolytes such as ZrO2, Sc2O3 and GeO2.

[0049] Step S202: preparing a primary solid electrolyte layer, molding a first mixture comprising LISICON solid electrolyte powder and a plasticizing solution to form a primary solid electrolyte layer.

[0050] Step S203: forming an integrated solid electrolyte layer and cathode layer, coating a second mixture comprising LISICON solid electrolyte powder and cathode material on one side of the primary solid electrolyte layer, and sintering to obtain an integrated solid electrolyte layer and cathode layer.

[0051] It is worth noting that the positive electrode material selected in this step can be the positive electrode material commonly used in the preparation of batteries, such as lithium ion compounds such as NCM, Li2CO3, LiN i0.8 Co 0.1 Mn 0.1 O2, Li3V2(PO4)2F3, Li3PO4, LiCrO2, etc.

[0052] against Figure 2 The technical solution provided by the illustrated embodiment is to form a primary solid electrolyte layer by molding a first mixture comprising LISICON-type solid electrolyte powder and a plasticizer solution, and then apply a second mixture comprising LISICON-type solid electrolyte powder and a positive electrode material to one side of the primary solid electrolyte layer and sinter. During the sintering process, on the one hand, a solid-phase reaction occurs between the LISICON-type solid electrolyte powder in the second mixture and the LISICON-type solid electrolyte powder on the surface of the primary solid electrolyte layer and the positive electrode material, so that the interface between the LISICON-type solid electrolyte powder and the positive electrode material can be eliminated; on the other hand, the primary solid electrolyte layer and the LISICON-type solid electrolyte powder in the second mixture interact with each other through hydrogen bonds or intermolecular van der Waals forces to form a whole, avoiding the appearance of a clear interface between the positive electrode and the solid electrolyte, effectively reducing the interface impedance between the positive electrode and the solid electrolyte, and thereby improving the electrical performance of the solid-state battery cell.

[0053] In addition, the solid electrolyte layer and positive electrode layer of the integrated structure prepared by the preparation method provided in the embodiment of the present invention reduce the interface impedance between the positive electrode and the solid electrolyte, and at the same time can improve the capacity density of the solid electrolyte layer, thereby effectively improving the rate performance of the solid-state battery cell.

[0054] In addition, compared with the existing method of preparing the solid electrolyte layer, positive electrode sheet and negative electrode sheet separately, the technical solution provided by the embodiment of the present invention is to simultaneously obtain the solid electrolyte layer and positive electrode layer of an integrated structure, omitting the separate preparation process of the positive electrode sheet and the assembly process between the positive electrode sheet and the solid electrolyte layer, effectively simplifying the solid-state battery cell preparation process and helping to reduce the manufacturing cost of the solid-state battery cell.

[0055] Furthermore, compared with liquid batteries, the solid electrolyte layer and positive electrode layer of the integrated structure can avoid problems such as battery combustion, explosion, and leakage, and has the advantage of higher safety.

[0056] The above steps S201, S202 and S203 will be described below respectively.

[0057] Specifically, with respect to step S201, a specific embodiment of preparing a LISICON-type solid electrolyte powder may include: mixing LISICON-type solid electrolyte materials according to a stoichiometric ratio, adding ball milling media to the mixture, and ball milling for 2 to 24 hours; vacuum drying or air drying the ball-milled mixture at 10°C to 100°C for 2 to 24 hours, and pre-sintering the dried mixture in an air atmosphere at 600°C to 1200°C for 5 to 20 hours; ball milling the pre-sintered material again for 2 to 12 hours, and vacuum drying it at 10°C to 100°C for 2 to 24 hours to obtain the LISICON-type solid electrolyte powder. For example, the ball milling time may be 2 hours, 5 hours, 10 hours, 15 hours, 20 hours, or 24 hours, and the drying temperature of the ball-milled mixture may be 10°C, 20°C, 40°C, 50°C, 80°C, or 100°C, i.e., the ball-milled mixture may be dried at room temperature or a temperature above room temperature. The drying time can be 2 hours, 5 hours, 10 hours, 15 hours, 20 hours, or 24 hours. Furthermore, the time for re-ball milling the pre-sintered material can be 2 hours, 5 hours, 10 hours, or 12 hours. The drying temperature of the re-ball milled mixture can be 10°C, 20°C, 40°C, 50°C, 80°C, or 100°C. The pre-sintering temperature can be 600°C, 800°C, 900°C, 1000°C, 1100°C, or 1200°C. The time for re-ball milling the pre-sintered material can be 2 hours, 5 hours, 10 hours, or 12 hours. The temperature for re-drying the pre-sintered material can be 10°C, 20°C, 40°C, 50°C, 80°C, or 100°C. The time for re-drying the pre-sintered material can be 2 hours, 5 hours, 10 hours, 15 hours, 20 hours, or 24 hours.

[0058] The multiple ball milling processes described above promote uniform mixing of the LISICON solid electrolyte materials and facilitate chemical reactions between the materials, resulting in a homogeneous sintered product. Furthermore, the combination of multiple ball milling, drying, and pre-sintering effectively removes impurities, increasing the content of active ingredients in the LISICON solid electrolyte powder and thereby increasing the capacitance of the subsequently prepared solid electrolyte.

[0059] Preferably, the LISICON-type solid electrolyte material includes at least the following materials: lithium carbonate (Li2CO3), silicon dioxide (SiO2), zirconium dioxide (ZrO2), diammonium hydrogen phosphate ((NH4)2HPO4), scandium oxide (Sc2O3) and germanium dioxide (GeO2).

[0060] More preferably, the LISICON-type solid electrolyte material comprises Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3, and GeO2 in a molar ratio of (2-10):(1-10):(1-10):(1:8):(0.1-1):(0.1-1). For example, the molar ratio of Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3, and GeO2 can be 2:1:1:1:0.1:0.1, 5:3:4:4:0.5:0.5, 7:8:6:5:0.7:0.6, 10:10:10:8:1:1, etc. By controlling the molar ratio of each component in the LISICON-type solid electrolyte material, the impurity content in the solid electrolyte powder and the solid electrolyte can be effectively reduced, and the effectiveness of the solid electrolyte made from the solid electrolyte powder can be improved.

[0061] It is worth noting that the above-mentioned LISICON solid electrolyte material is only a preferred solution. Those skilled in the art may also select electrolyte materials commonly used in existing LISICON solid-state batteries and obtain LISICON solid electrolyte powder through the above-mentioned step S201.

[0062] Regarding step S202 , the implementation means may include: pressing a third mixture formed by LISICON solid electrolyte powder and plasticizing solution to form a first primary solid electrolyte layer.

[0063] Among them, the plasticizing solution generally refers to improving the adhesion between LISICON solid electrolyte powders so that the LISICON solid electrolyte powders can quickly form the first primary solid electrolyte layer. Exemplarily, the plasticizing solution can be a plasticizer commonly used in solid-state batteries, such as a polyvinyl alcohol (PVA) aqueous solution. Exemplarily, the mass fraction of the plasticizing solution in the third mixture can be 0.5% to 4%. For example, the mass fraction of the plasticizing solution in the third mixture can be 0.5%, 1%, 1.5%, 2%, 3%, 3.5% or 4%, etc. By controlling the mass fraction of the plasticizing solution in the third mixture, it can be effectively ensured that the plasticizing solution adheres to the LISICON solid electrolyte powder and can ensure that the LISICON solid electrolyte powder is evenly distributed in the solid electrolyte layer.

[0064] The plasticizing solution in the third mixture can be prepared by mixing an aqueous solution containing 1% to 5% by mass of a plasticizer with LISICON solid electrolyte powder to prepare a third mixture containing 0.5% to 4% by mass of a plasticizing solution.

[0065] Furthermore, on the basis of forming the first primary solid electrolyte layer, step S202 may further include: applying a fourth mixture formed by LISICON solid electrolyte powder, volatile material and plasticizer solution to the main surface of one side of the first primary solid electrolyte layer to form a second primary solid electrolyte layer; first, synchronously sintering the first primary solid electrolyte layer and the second primary solid electrolyte layer at a temperature of 60°C to 120°C for 0.5h to 2h, then raising the temperature to 400°C to 600°C, continuing to synchronously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 1h to 4h, further raising the temperature to 1000°C to 1300°C, and continuing to synchronously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 10h to 18h to form a solid electrolyte layer with a porous structure on one main surface.

[0066] The volatile material can be any volatile material such as starch, organic molecular volatile material, dispersant, etc.

[0067] For example, in the above process, the temperature of the first synchronous sintering step may be 60°C, 70°C, 80°C, 100°C, 110°C, or 120°C, and the time of the first synchronous sintering step may be 0.5h, 1h, 1.5h, or 2h. The temperature of the second synchronous sintering step may be 400°C, 420°C, 450°C, 500°C, 550°C, or 600°C, and the time of the second synchronous sintering step may be 1h, 1.5h, 2h, 3h, or 4h. The temperature of the third synchronous sintering step may be 1000°C, 1100°C, 1200°C, or 1300°C, and the time of the third synchronous sintering step may be 10h, 12h, 15h, 16h, or 18h.

[0068] The mass fraction of the volatile material in the fourth mixture is generally 0.5% to 4%. For example, the mass fraction of the volatile material in the fourth mixture can be 0.5%, 1%, 1.5%, 2%, 3% or 4%.

[0069] In the porous solid electrolyte layer, the porosity of the porous structure can be 1% to 15%; the pore diameter can be 0.1μm to 5μm. For example, the porosity of the porous structure can be 1%, 5%, 8%, 10%, 12% or 15%, and the pore diameter can be 0.1μm, 0.5μm, 1μm, 1.5μm, 2μm, 3μm or 5μm. By controlling the porosity and pore diameter of the porous structure, it is possible to ensure that the subsequent positive electrode layer forms a stable contact with the solid electrolyte layer while eliminating the interface impedance between the positive electrode layer and the solid electrolyte layer.

[0070] The thickness of the solid electrolyte layer formed by the above process may be 5 μm to 30 μm. For example, the thickness of the solid electrolyte layer may be 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm.

[0071] Furthermore, the above step S203 can be implemented in two specific ways.

[0072] Specifically, the first method for implementing step S203 is based on the first primary solid electrolyte layer prepared above. More specifically, a second mixture comprising LISICON solid electrolyte powder and a positive electrode material is applied to one side of the first primary solid electrolyte layer to form a primary positive electrode layer. The first primary solid electrolyte layer and the primary positive electrode layer are then simultaneously sintered to form an integrated solid electrolyte layer and positive electrode layer. This process effectively simplifies the preparation process while reducing the interfacial impedance between the solid electrolyte layer and the positive electrode layer.

[0073] In addition, the second means of implementing step S203 is completed on the basis of the solid electrolyte layer with a porous structure formed as described above. Specifically, a second mixture containing LISICON-type solid electrolyte powder and a positive electrode material is applied to one side of the solid electrolyte layer with a porous structure and sintered at 600°C to 900°C for 6h to 16h. Exemplarily, the sintering temperature for forming the porous structure can be 600°C, 700°C, 800°C or 900°C, etc., and the sintering time for forming the porous structure can be 6h, 10h, 12h, 15h or 16h, etc. By controlling the sintering temperature and sintering time of this step, on the one hand, all the moisture in the second mixture can be removed, while ensuring the uniformity of the formed porous structure and the porosity and pore distribution of the porous structure.

[0074] Further, if Figure 2As shown, the above-mentioned method for preparing a solid-state battery cell may further include: Step S204: Providing a negative electrode layer. The negative electrode layer is provided on the main surface of the solid electrolyte layer away from the positive electrode layer. This step can be performed by physical deposition, direct application of metallic sodium / metallic lithium to the solid electrolyte layer, or coating the solid electrolyte layer with a negative electrode slurry. The negative electrode material can be metallic sodium, a tin-based material, hard carbon, or graphite.

[0075] It is worth noting that the negative electrode layer can also be prepared using the above-mentioned positive electrode layer preparation method. Regarding the case where the negative electrode layer is prepared using the above-mentioned positive electrode layer preparation method, those skilled in the art can understand the preparation process of the negative electrode layer based on the description of the above-mentioned positive electrode layer preparation process, and will not be repeated here.

[0076] In addition, the adjustment relationship between the thickness of the positive electrode layer and the thickness of the solid electrolyte layer can be obtained through multiple experiments based on the capacity requirements of the solid-state battery cell.

[0077] In summary, the embodiments of the present invention provide two technical solutions for preparing solid-state battery cells.

[0078] Specifically, if Figure 3 and Figure 4 As shown, the first technical solution for preparing a solid-state battery cell may include the following steps:

[0079] Step S301: Mixing and ball milling according to the molar ratio: (2-10): (1-10): (1-10):

[0080] (1:8):(0.1~1):(0.1~1) Mix Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3 and GeO2, add ball milling media to the mixture, and ball mill for 2h~24h.

[0081] Step S302: Pre-sintering treatment, vacuum drying / air drying the ball-milled mixture at 10° C. to 100° C. for 2 h to 24 h, and pre-sintering the dried mixture in an air atmosphere at 600° C. to 1200° C. for 5 h to 20 h.

[0082] Step S303 : Drying treatment: the pre-sintered material is ball-milled again for 2 hours to 12 hours, and vacuum-dried at 10° C. to 100° C. for 2 hours to 24 hours to obtain LISICON type solid electrolyte powder 11 .

[0083] For example, Figure 4 As shown, after the above steps S301 to S303 are processed, the solid electrolyte powder 11 is obtained.

[0084] Step S304: a pressing and molding process, in which a third mixture formed by the LISICON solid electrolyte powder 11 and the plasticizing solution is pressed to form a first primary solid electrolyte layer 12 ′.

[0085] Step S305: coating treatment, coating a fourth mixture formed by the LISICON solid electrolyte powder 11, the volatile material and the plasticizing solution on one main surface of the first primary solid electrolyte layer 12' to form a second primary solid electrolyte layer 13'.

[0086] Step S306: Sintering treatment, first at a temperature of 60℃~120℃, synchronously sinter the first primary solid electrolyte layer 12' and the second primary solid electrolyte layer 13' for 0.5h~2h, then raise the temperature to 400℃~600℃, continue to synchronously sinter the first primary solid electrolyte layer 12' and the second primary solid electrolyte layer 13' for 1h~4h, further raise the temperature to 1000℃~1300℃, continue to synchronously sinter the first primary solid electrolyte layer 12' and the second primary solid electrolyte layer 13' for 10h~18h, to form a solid electrolyte layer 10 with a porous structure on one main surface.

[0087] like Figure 4 As shown, the solid electrolyte layer 10 includes a complete first solid electrolyte layer 12 at the bottom and a second solid electrolyte layer 13 with a porous structure.

[0088] Step S307: coating and sintering treatment, coating the second mixture containing LISICON solid electrolyte powder 11 and positive electrode material on the porous side of the solid electrolyte layer, and sintering at 600° C. to 900° C. for 6 h to 16 h to form a positive electrode layer 20 ′.

[0089] Step S308 : providing a negative electrode layer. The negative electrode layer 30 ′ is provided on the main surface of the solid electrolyte layer 10 away from the positive electrode layer 20 ′.

[0090] The structural changes brought about by the above steps S301 to S308 can be as follows Figure 4 shown.

[0091] like Figure 5 and Figure 6 As shown, the first technical solution for preparing a solid-state battery cell may include the following steps:

[0092] Step S501: Mixing and ball milling treatment, mix Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3 and GeO2 according to the molar ratio of (2~10):(1~10):(1~10):(1:8):(0.1~1):(0.1~1), add ball milling media to the mixture, and ball mill for 2h~24h.

[0093] Step S502: Pre-sintering treatment, vacuum drying / air drying the ball-milled mixture at 10° C. to 100° C. for 2 h to 24 h, and pre-sintering the dried mixture in an air atmosphere at 600° C. to 1200° C. for 5 h to 20 h.

[0094] Step S503 : Drying treatment: the pre-sintered material is ball-milled again for 2 hours to 12 hours, and vacuum-dried at 10° C. to 100° C. for 2 hours to 24 hours to obtain LISICON type solid electrolyte powder 11 .

[0095] Step S504: a pressing and molding process, in which a third mixture formed by the LISICON solid electrolyte powder 11 and the plasticizing solution is pressed to form a first primary solid electrolyte layer 12 ′.

[0096] Step S505: coating treatment, coating a second mixture comprising the LISICON solid electrolyte powder 11 and the positive electrode material on one side of the first primary solid electrolyte layer to form a primary positive electrode layer 20".

[0097] Step S506: sintering treatment, synchronously sintering the first primary solid electrolyte layer 12' and the primary positive electrode layer 20", to obtain the solid electrolyte layer 10 and the positive electrode layer 20' of an integrated structure.

[0098] Step S507 : providing a negative electrode layer. The negative electrode layer 30 ′ is provided on the main surface of the solid electrolyte layer 10 away from the positive electrode layer 20 ′.

[0099] The structural changes brought about by the above steps S501 to S507 can be as follows Figure 6 shown.

[0100] Furthermore, an embodiment of the present invention further provides a solid-state battery cell, which is prepared by the solid-state battery cell preparation method provided by each of the above embodiments. Specifically, the solid-state battery cell may include: a solid electrolyte layer and a positive electrode layer integrally formed with the solid electrolyte layer.

[0101] Furthermore, the solid-state battery cell may further include a negative electrode layer.

[0102] In addition, an embodiment of the present invention further provides a solid-state battery, which may include the solid-state battery cell provided in the above embodiment.

[0103] The integrated structure of the solid electrolyte layer and the positive electrode layer reduces the interfacial impedance between the positive electrode and the solid electrolyte, while increasing the capacity density of the solid electrolyte layer, thereby effectively improving the rate performance of the solid-state battery cell and the solid-state battery having the solid-state battery cell.

[0104] The performance of the solid-state battery prepared by the technical solution provided by the embodiment of the present invention is described in detail below with two specific examples and a comparative example.

[0105] Example 1:

[0106] Step A1: Prepare LISICON solid electrolyte powder.

[0107] Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3, and GeO2 were mixed in a molar ratio of 6.875:8:7:4:0.25:0.5, and a certain volume of isopropyl alcohol was added as a ball-milling medium. The mixture was ball-milled for 12 hours. The ball-milled mixture was dried in a 50°C vacuum oven for 12 hours and then pre-sintered in air at 900°C for 12 hours. The pre-sintered sample was ball-milled again for 6 hours and then dried in a 50°C vacuum oven for 12 hours.

[0108] Step B1: Pressing and sintering to obtain LISICON solid electrolyte.

[0109] A PVA aqueous solution containing 5 wt% by mass as a plasticizer is added to the electrolyte powder to form a mixture containing 2 wt% by mass of the PVA aqueous solution, and the mixture is pressed into shape.

[0110] The pressed sample was heated at 100 °C for 1 h to remove moisture, then sintered at 500 °C for 2 h to ensure complete decomposition of PVA, and finally sintered at 1100 °C for 12 h to obtain the LISICON solid electrolyte.

[0111] Step C1: preparing an integrated structure of a positive electrode layer and a LISICON solid electrolyte layer.

[0112] The LISICON solid electrolyte powder is mixed with the NCM precursor (such as LiN i0.8 Co 0.1 Mn 0.1 O2) and a lithium source (such as Li2CO3) are mixed and the mixture is coated on one side of the LISICON solid electrolyte layer.

[0113] The above structure was sintered at 800°C for 10 hours to allow the NCM precursor to react with Li2CO3 to generate NCM positive electrode material, which was then sintered integrally with the LISICON solid electrolyte layer.

[0114] Step D1: Preparation of negative electrode layer: Sodium metal is deposited on the other side of the LISICON solid electrolyte layer to obtain the negative electrode layer.

[0115] Step E1: Assembling the battery: Assemble the positive electrode layer, solid electrolyte layer, and negative electrode layer prepared above into a button battery.

[0116] Example 2:

[0117] Step A2: preparing LISICON solid electrolyte powder, which is consistent with the method of preparing LISICON solid electrolyte powder in Example 1 above.

[0118] Step B2: Pressing and sintering to obtain LISICON solid electrolyte, which is consistent with the method of preparing LISICON solid electrolyte in Example 1 above.

[0119] Step C2: preparing an integrated structure of the positive electrode layer and the LISICON solid electrolyte layer.

[0120] The LISICON solid electrolyte powder is mixed with a Li3V2(PO4)2F3 precursor and a lithium source (eg, Li3PO4), and the mixture is coated on one side of the LISICON solid electrolyte layer.

[0121] The above structure was sintered at 700°C for 8 hours to allow the Li3V2(PO4)2F3 precursor to react with Li3PO4 to generate Li3V2(PO4)2F3 positive electrode material, which was then sintered integrally with the LISICON solid electrolyte layer.

[0122] Step D2: Prepare the negative electrode layer. The Sn4P3@CNT / C negative electrode material is coated on the other side of the LISICON solid electrolyte layer to obtain the negative electrode layer.

[0123] Step E2: Assembling the battery: Assemble the positive electrode layer, solid electrolyte layer, and negative electrode layer prepared above into a soft pack battery.

[0124] Comparative Example:

[0125] Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3 and GeO2 are directly mixed, pressed and sintered to form the LISICON solid electrolyte layer.

[0126] A positive electrode layer is deposited on one side of the LISICON solid electrolyte layer by physical deposition, and a negative electrode layer is deposited on the other side of the LISICON solid electrolyte layer by physical deposition to obtain a solid-state battery cell, which is then assembled into a solid-state button battery using the solid-state battery cell.

[0127] By conducting cyclic electrical performance tests on the solid-state batteries obtained in Example 1, Example 2 and the comparative example, it was found through multiple test results that the internal resistance of the solid-state batteries of Example 1 and Example 2 was in the range of 0.1 to 0.2 mΩ, and the internal resistance of the solid-state battery of the comparative example was in the range of 0.7 to 0.9 mΩ, indicating that the integrated preparation of the solid-state electrolyte layer and the positive electrode layer is beneficial to reducing the interface impedance, improving the lithium ion transmission capacity of the positive electrode, and improving the battery performance.

[0128] The above steps are merely provided to help understand the structure, method, and core concept of the present invention. It will be apparent to those skilled in the art that various improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a solid-state battery cell, characterized in that: include: Step 1: preparing LISICON solid electrolyte powder; Step 2: forming the first mixture comprising the LISICON solid electrolyte powder and the plasticizing solution to form a primary solid electrolyte layer; Step 3: coating a second mixture comprising the LISICON solid electrolyte powder and a cathode material on one side of the primary solid electrolyte layer and sintering the mixture to obtain a solid electrolyte layer and a cathode layer of an integrated structure.

2. The method for preparing a solid-state battery cell according to claim 1, wherein: Step 1 includes: Step 11: Mixing LISICON solid electrolyte materials according to a stoichiometric ratio, adding ball milling media to the mixture, and ball milling for 2 hours to 24 hours; Step 12: vacuum drying / air drying the ball-milled mixture at 10° C. to 100° C. for 2 h to 24 h, and pre-sintering the dried mixture in an air atmosphere at 600° C. to 1200° C. for 5 h to 20 h; Step 13: ball-mill the pre-sintered material again for 2 h to 12 h, and vacuum-dry at 10° C. to 100° C. for 2 h to 24 h to obtain LISICON solid electrolyte powder.

3. The method for preparing a solid-state battery cell according to claim 2, wherein: The LISICON type solid electrolyte material includes at least the following materials: lithium carbonate (Li2CO3), silicon dioxide (SiO2), zirconium dioxide (ZrO2), diammonium phosphate ((NH4)2HPO4), scandium oxide (Sc2O3), and germanium dioxide (GeO2); Preferably, The LISICON type solid electrolyte material includes Li2CO3, SiO2, ZrO2, (NH4)2HPO4, Sc2O3 and GeO2 in a molar ratio of: (2~10): (1~10): (1~10): (1:8): (0.1~1): (0.1~1).

4. The method for preparing a solid-state battery cell according to claim 1, wherein: Step 2 includes: Step 21: Press a third mixture formed by the LISICON solid electrolyte powder and the plasticizer solution to form a first primary solid electrolyte layer.

5. The method for preparing a solid-state battery cell according to claim 1 or 4, characterized in that: Step 2 also includes: Step 22: applying a fourth mixture formed by LISICON solid electrolyte powder, a volatile material, and a plasticizing solution to one main surface of the first primary solid electrolyte layer to form a second primary solid electrolyte layer; Step 23: First, simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer at a temperature of 60°C to 120°C for 0.5h to 2h, then raise the temperature to 400°C to 600°C, continue to simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 1h to 4h, further raise the temperature to 1000°C to 1300°C, continue to simultaneously sinter the first primary solid electrolyte layer and the second primary solid electrolyte layer for 10h to 18h, to form a solid electrolyte layer with a porous structure on one main surface.

6. The method for preparing a solid-state battery cell according to claim 5, wherein: Step 3 comprises: applying a second mixture comprising the LISICON solid electrolyte powder and a positive electrode material to one side of the solid electrolyte layer having a porous structure, and sintering at 600° C. to 900° C. for 6 h to 16 h; and / or, The mass fraction of the volatile material in the fourth mixture is 0.5% to 4%; and / or, In the porous solid electrolyte layer, the porosity of the porous structure is 1% to 15%; the pore diameter is 0.1 μm to 5 μm; and / or, The thickness of the solid electrolyte layer is 5 μm to 30 μm.

7. The method for preparing a solid-state battery cell according to claim 1 or 4, characterized in that: Step 3 includes: Step 31: applying a second mixture comprising the LISICON solid electrolyte powder and a cathode material to one side of the first primary solid electrolyte layer to form a primary cathode layer; Step 32: Simultaneously sintering the first primary solid electrolyte layer and the primary positive electrode layer to obtain a solid electrolyte layer and a positive electrode layer of an integrated structure.

8. The method for preparing a solid-state battery cell according to any one of claims 1 to 7, characterized in that: Also includes: Step 4: Disposing a negative electrode layer on the main surface of the solid electrolyte layer away from the positive electrode layer.

9. A solid-state battery cell, characterized in that: The solid-state battery cell is prepared by the preparation method according to any one of claims 1 to 8, and comprises: a solid electrolyte layer and a positive electrode layer having an integrated structure with the solid electrolyte layer.

10. A solid-state battery, characterized in that: include: The solid-state battery cell according to claim 9.

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