All-solid-state sodium ion battery preparation method based on in-situ polymerization

Abstract

The invention discloses an all-solid-state sodium ion battery preparation method based on in-situ polymerization, which belongs to the technical field of battery preparation and comprises the following steps: preparing raw materials, preparing an electrolyte precursor, performing an in-situ polymerization process, assembling a battery and testing the battery. According to the method, the in-situ polymerization technology is adopted, the electrolyte can be directly generated in electrode pores, the filling rate is larger than 95%, the interface contact resistance can be reduced to be smaller than 50 omega.cm < 2 >, the ion transmission efficiency is remarkably improved, the multi-step process of electrolyte membrane preparation-lamination-hot pressing of a traditional solid-state battery is omitted, the electrolyte is directly generated in the electrode, and the battery efficiency is improved. According to the method, the positive electrode / negative electrode interface can be optimized at the same time by regulating and controlling the formula of the precursor, the overall quality of the battery is improved, and the actual application effect of the method is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery preparation, and in particular relates to a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization. Background Art

[0002] Solid-state batteries are a new type of battery technology that uses solid electrolytes instead of traditional liquid electrolytes. The positive electrode, negative electrode, and electrolyte are all solid. This fundamental change gives solid-state batteries significant advantages in safety, energy density, and charging speed. However, the preparation of solid-state batteries requires the application of specific preparation methods.

[0003] A Chinese patent (CN116632248A) discloses a method for preparing a solid-state battery and a solid-state battery, belonging to the field of solid-state battery technology. The method comprises obtaining a positive electrode polymer solution and a negative electrode polymer solution; mixing the positive electrode polymer solution with a positive electrode active material, a conductive agent, and a binder to obtain a positive electrode active slurry, and applying the mixture to the surface of a current collector to obtain a positive electrode sheet; mixing the negative electrode polymer solution with a negative electrode active material, a conductive agent, and a binder to obtain a negative electrode active slurry, and applying the mixture to the surface of a current collector to obtain a negative electrode sheet; mixing a plasticizer, a solid electrolyte material, and a binder to obtain an electrolyte slurry to obtain a solid electrolyte sheet; and assembling the negative electrode sheet, the solid electrolyte sheet, and the positive electrode sheet through a lamination process. This method improves the interfacial contact between the electrode and the solid electrolyte from the perspective of molecular motion, thereby enhancing the stability of the interface between the electrode and the solid electrolyte. Although current preparation methods can complete the preparation of solid-state batteries, they do not use in-situ polymerization technology and cannot improve the ion transfer efficiency. The multi-step process of electrolyte membrane preparation-lamination-hot pressing cannot improve the overall production efficiency of the battery, and the actual application effect is poor. There is an urgent need for a preparation method for all-solid-state sodium-ion batteries based on in-situ polymerization. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that although the current preparation method can complete the preparation of solid-state batteries, it does not use in-situ polymerization technology, cannot improve the ion transmission efficiency, adopts an electrolyte membrane preparation-lamination-hot pressing multi-step process, cannot improve the overall production efficiency of the battery, and has poor actual application effect. A method for preparing an all-solid-state sodium ion battery based on in-situ polymerization is proposed.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, comprising the following steps:

[0006] S1. Prepare raw materials;

[0007] S2. preparing an electrolyte precursor;

[0008] S3, performing an in-situ polymerization process;

[0009] S4, assembling batteries;

[0010] S5. Perform battery test.

[0011] By adopting the above technical solution and in-situ polymerization technology, electrolyte can be directly generated in the electrode pores, with a filling rate of >95% and the interface contact resistance can be reduced to <50Ω·cm 2 , significantly improving the ion transfer efficiency. This method eliminates the multi-step process of electrolyte membrane preparation-bonding-hot pressing of traditional solid-state batteries, and directly generates electrolyte inside the electrode, greatly shortening the battery production cycle. This method can simultaneously optimize the positive / negative electrode interface by regulating the precursor formula, thereby improving the overall quality of the battery, and the method has good practical application effect.

[0012] As a further description of the above technical solution:

[0013] In the above S1, raw materials are prepared, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, and the battery negative electrode materials include hard carbon, metallic sodium and alloys.

[0014] As a further description of the above technical solution:

[0015] In the S1, the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, the conductive agent and the binder is 7:1:1. PVDF is first dissolved in NMP, the temperature is controlled to 25-35°C, and stirred for 2 hours. Then, the active material and the conductive agent are added. The material is then placed in a blender, the stirring rate is set to 1500-2000r / min, stirred for 10-15 minutes, and vacuum degassing is performed. After the slurry is prepared, it is coated using a coating machine.

[0016] As a further description of the above technical solution:

[0017] In the above-mentioned S1, the coating thickness is maintained at 250-320 μm. After coating, the coated surface is quickly dried by using a drying air at 70-80° C.

[0018] As a further description of the above technical solution:

[0019] In the S2, an electrolyte precursor is prepared, and the specific steps are as follows: prepare sodium salt, initiator and monomer, wherein polyethylene glycol diacrylate is selected as the monomer, sodium bis(trifluoromethanesulfonyl)imide is selected as the sodium salt, and the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and the monomer in a mixing device, stir magnetically for 5-6 hours, then add the initiator and continue stirring for 1-2 hours until it is completely transparent.

[0020] As a further description of the above technical solution:

[0021] In the above S2, when preparing the electrolyte precursor, viscosity control needs to be performed by adding 10 wt% propylene carbonate as a diluent to reduce the viscosity to 200-300 mPa·s.

[0022] As a further description of the above technical solution:

[0023] In the above-mentioned S3, an in-situ polymerization process is performed, and the specific steps are: injecting the prepared precursor and performing a photopolymerization treatment.

[0024] As a further description of the above technical solution:

[0025] In S3, the precursor injection includes plasma cleaning and vacuum impregnation. In the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes. In the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 2-3 hours.

[0026] As a further description of the above technical solution:

[0027] In the S4, battery assembly is performed, and the specific steps are: lamination and pre-pressing are performed, and the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode. The electrolyte membrane is kept at 30μm. During the pre-pressing treatment, the pressure is set to 10-15MPa, the temperature is 90°C, and the time is 15-20min. Finally, the battery is packaged.

[0028] As a further description of the above technical solution:

[0029] In S5, battery testing is performed, including electrolyte characterization testing and battery performance testing, wherein the electrolyte characterization testing also includes ion conductivity testing and electrochemical window testing, and the battery performance testing also includes battery cycle performance testing and battery rate performance testing.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] In the present invention, the method adopts in-situ polymerization technology, which can directly generate electrolytes in the electrode pores, with a filling rate of >95% and an interface contact resistance of <50Ω·cm 2 , significantly improving the ion transfer efficiency. This method eliminates the multi-step process of electrolyte membrane preparation-bonding-hot pressing of traditional solid-state batteries, and directly generates electrolyte inside the electrode, greatly shortening the battery production cycle. This method can simultaneously optimize the positive / negative electrode interface by regulating the precursor formula, thereby improving the overall quality of the battery, and the method has good practical application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a method for preparing an all-solid-state sodium ion battery based on in situ polymerization. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1

[0035] See also Figure 1 The present invention provides a technical solution: a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, comprising the following steps:

[0036] S1. Prepare raw materials, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, the battery negative electrode materials include hard carbon, metallic sodium and alloys, and the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, conductive agent and binder is 7:1:1. First, dissolve PVDF in NMP, control the temperature to 25°C, stir for 2h, then add the active material and the conductive agent, and then put the material into a blender, set the stirring rate to 1500r / min, stir for 10min, and perform vacuum degassing. After the slurry is prepared, it is coated with a coating machine, and the coating thickness is maintained at 250μm. After coating, the coated surface is quickly dried with dry air at 70°C;

[0037] S2. Prepare an electrolyte precursor, the specific steps of which are: prepare sodium salt, initiator and monomer, the monomer is polyethylene glycol diacrylate, the sodium salt is sodium bis(trifluoromethanesulfonyl imide), the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and monomer in a mixing device, magnetically stir for 5 hours, then add the initiator and continue stirring for 1 hour until completely transparent, when preparing the electrolyte precursor, viscosity control is required, the method is to add 10wt% propylene carbonate as a diluent to reduce the viscosity to 200mPa·s;

[0038] S3, performing an in-situ polymerization process, specifically comprising the following steps: injecting the prepared precursor and performing a photopolymerization treatment, wherein the precursor injection includes plasma cleaning and vacuum impregnation, wherein during the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes, and during the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 2 hours;

[0039] S4, assembling the battery, specifically the following steps: lamination and pre-pressing, the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode, the electrolyte membrane is kept at 30 μm, during the pre-pressing treatment, the pressure is set to 10 MPa, the temperature is 90°C, the time is 15 minutes, and finally the battery is packaged;

[0040] S5. Conduct battery tests, including electrolyte characterization tests and battery performance tests. The electrolyte characterization tests also include ionic conductivity tests and electrochemical window tests. The battery performance tests also include battery cycle performance tests and battery rate performance tests.

[0041] In this embodiment, the method adopts in-situ polymerization technology, which can directly generate electrolyte in the electrode pores, with a filling rate of >95% and an interface contact resistance of <50Ω·cm. 2 , significantly improving ion transmission efficiency.

[0042] Example 2

[0043] See also Figure 1 The present invention provides a technical solution: a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, comprising the following steps:

[0044] S1. Prepare raw materials, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, the battery negative electrode materials include hard carbon, metallic sodium and alloys, and the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, the conductive agent and the binder is 7:1:1. First, dissolve PVDF in NMP, control the temperature to 30°C, stir for 2h, then add the active material and the conductive agent, and then put the material into a blender, set the stirring rate to 1600r / min, stir for 12min, and perform vacuum degassing. After the slurry is prepared, it is coated with a coating machine, and the coating thickness is maintained at 300μm. After coating, the coated surface is quickly dried with dry air at 75°C;

[0045] S2. Prepare an electrolyte precursor, the specific steps of which are: prepare sodium salt, initiator and monomer, the monomer is polyethylene glycol diacrylate, the sodium salt is sodium bis(trifluoromethanesulfonyl imide), the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and monomer in a mixing device, magnetically stir for 5 hours, then add the initiator and continue stirring for 1 hour until completely transparent, when preparing the electrolyte precursor, viscosity control is required, the method is to add 10wt% propylene carbonate as a diluent to reduce the viscosity to 250mPa·s;

[0046] S3, performing an in-situ polymerization process, specifically comprising the following steps: injecting the prepared precursor and performing a photopolymerization treatment, wherein the precursor injection includes plasma cleaning and vacuum impregnation, wherein during the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes, and during the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 2 hours;

[0047] S4, assembling the battery, specifically the following steps: lamination and pre-pressing, the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode, the electrolyte membrane is kept at 30 μm, during the pre-pressing treatment, the pressure is set to 12 MPa, the temperature is 90°C, the time is 18 minutes, and finally the battery is packaged;

[0048] S5. Conduct battery tests, including electrolyte characterization tests and battery performance tests. The electrolyte characterization tests also include ionic conductivity tests and electrochemical window tests. The battery performance tests also include battery cycle performance tests and battery rate performance tests.

[0049] In this embodiment, the method omits the multi-step process of electrolyte membrane preparation-bonding-hot pressing of traditional solid-state batteries, and directly generates electrolyte inside the electrode, greatly shortening the battery production cycle.

[0050] Example 3

[0051] See also Figure 1 The present invention provides a technical solution: a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, comprising the following steps:

[0052] S1. Prepare raw materials, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, the battery negative electrode materials include hard carbon, metallic sodium and alloys, and the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, the conductive agent and the binder is 7:1:1. First, dissolve PVDF in NMP, control the temperature to 35°C, stir for 2h, then add the active material and the conductive agent, and then put the material into a blender, set the stirring rate to 2000r / min, stir for 15min, and perform vacuum degassing. After the slurry is prepared, it is coated with a coating machine, and the coating thickness is maintained at 320μm. After coating, the coated surface is quickly dried with dry air at 80°C;

[0053] S2. Prepare an electrolyte precursor, the specific steps of which are: prepare sodium salt, initiator and monomer, the monomer is polyethylene glycol diacrylate, the sodium salt is sodium bis(trifluoromethanesulfonyl imide), the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and monomer in a mixing device, magnetically stir for 6 hours, then add the initiator and continue stirring for 2 hours until completely transparent, when preparing the electrolyte precursor, viscosity control is required, the method is to add 10wt% propylene carbonate as a diluent to reduce the viscosity to 300mPa·s;

[0054] S3, performing an in-situ polymerization process, specifically comprising the following steps: injecting the prepared precursor and performing a photopolymerization treatment, wherein the precursor injection includes plasma cleaning and vacuum impregnation, wherein during the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes, and during the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 3 hours;

[0055] S4, assembling the battery, specifically the following steps: lamination and pre-pressing, the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode, the electrolyte membrane is kept at 30 μm, during the pre-pressing treatment, the pressure is set to 15 MPa, the temperature is 90°C, the time is 20 min, and finally the battery is packaged;

[0056] S5. Conduct battery tests, including electrolyte characterization tests and battery performance tests. The electrolyte characterization tests also include ionic conductivity tests and electrochemical window tests. The battery performance tests also include battery cycle performance tests and battery rate performance tests.

[0057] In this embodiment, the method can simultaneously optimize the positive electrode / negative electrode interface and improve the overall quality of the battery by regulating the precursor formula, and the method has good practical application effect.

[0058] Example 4

[0059] See also Figure 1 The present invention provides a technical solution: a method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, comprising the following steps:

[0060] S1. Prepare raw materials, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, the battery negative electrode materials include hard carbon, metallic sodium and alloys, and the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, conductive agent and binder is 7:1:1. First, dissolve PVDF in NMP, control the temperature to 35°C, stir for 2h, then add the active material and the conductive agent, and then put the material into a blender, set the stirring rate to 1800r / min, stir for 15min, and perform vacuum degassing. After the slurry is prepared, it is coated with a coating machine, and the coating thickness is maintained at 320μm. After coating, the coated surface is quickly dried with dry air at 80°C;

[0061] S2. Prepare an electrolyte precursor, the specific steps of which are: prepare sodium salt, initiator and monomer, the monomer is polyethylene glycol diacrylate, the sodium salt is sodium bis(trifluoromethanesulfonyl imide), the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and monomer in a mixing device, magnetically stir for 6 hours, then add the initiator and continue stirring for 2 hours until completely transparent, when preparing the electrolyte precursor, viscosity control is required, the method is to add 10wt% propylene carbonate as a diluent to reduce the viscosity to 300mPa·s;

[0062] S3, performing an in-situ polymerization process, specifically comprising the following steps: injecting the prepared precursor and performing a photopolymerization treatment, wherein the precursor injection includes plasma cleaning and vacuum impregnation, wherein during the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes, and during the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 2 hours;

[0063] S4, assembling the battery, specifically the following steps: lamination and pre-pressing, the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode, the electrolyte membrane is kept at 30 μm, during the pre-pressing treatment, the pressure is set to 15 MPa, the temperature is 90°C, the time is 18 minutes, and finally the battery is packaged;

[0064] S5. Conduct battery tests, including electrolyte characterization tests and battery performance tests. The electrolyte characterization tests also include ionic conductivity tests and electrochemical window tests. The battery performance tests also include battery cycle performance tests and battery rate performance tests.

[0065] In Examples 1-4, the method uses in-situ polymerization technology to generate electrolyte directly in the electrode pores, with a filling rate of >95% and an interface contact resistance of <50Ω·cm 2 , significantly improving the ion transfer efficiency. This method eliminates the multi-step process of electrolyte membrane preparation-bonding-hot pressing of traditional solid-state batteries, and directly generates electrolyte inside the electrode, greatly shortening the battery production cycle. This method can simultaneously optimize the positive / negative electrode interface by regulating the precursor formula, thereby improving the overall quality of the battery, and the method has good practical application effect.

[0066] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an all-solid-state sodium ion battery based on in-situ polymerization, characterized in that: The steps include: S1. Prepare raw materials; S2. preparing an electrolyte precursor; S3, performing an in-situ polymerization process; S4, assembling batteries; S5. Perform battery test.

2. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the above S1, raw materials are prepared, including battery positive electrode materials, battery negative electrode materials and electrode slurry, wherein the battery positive electrode materials include layered oxides and polyanion compounds, and the battery negative electrode materials include hard carbon, metallic sodium and alloys.

3. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the S1, the electrode slurry consists of NVP, a conductive agent and a binder, wherein the weight fraction ratio of NVP, the conductive agent and the binder is 7:1:

1. PVDF is first dissolved in NMP, the temperature is controlled to 25-35°C, and stirred for 2 hours. Then, the active material and the conductive agent are added. The material is then placed in a blender, the stirring rate is set to 1500-2000r / min, stirred for 10-15 minutes, and vacuum degassing is performed. After the slurry is prepared, it is coated using a coating machine.

4. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the above-mentioned S1, the coating thickness is maintained at 250-320 μm. After coating, the coated surface is quickly dried by using a drying air at 70-80° C.

5. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the S2, an electrolyte precursor is prepared, and the specific steps are as follows: prepare sodium salt, initiator and monomer, wherein polyethylene glycol diacrylate is selected as the monomer, sodium bis(trifluoromethanesulfonyl)imide is selected as the sodium salt, and the initiator is divided into thermal initiator and photoinitiator, wherein the photoinitiator is trimethylbenzoyl and the thermal initiator is azobisisobutyronitrile, place the sodium salt and the monomer in a mixing device, stir magnetically for 5-6 hours, then add the initiator and continue stirring for 1-2 hours until it is completely transparent.

6. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the above S2, when preparing the electrolyte precursor, viscosity control needs to be performed by adding 10 wt% propylene carbonate as a diluent to reduce the viscosity to 200-300 mPa·s.

7. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the above-mentioned S3, an in-situ polymerization process is performed, and the specific steps are: injecting the prepared precursor and performing a photopolymerization treatment.

8. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In S3, the precursor injection includes plasma cleaning and vacuum impregnation. In the plasma cleaning, the electrode surface is treated with O2 plasma at a power of 50W for 3 minutes. In the vacuum impregnation, the electrode is immersed in the precursor solution and placed in a vacuum chamber for 2-3 hours.

9. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In the S4, battery assembly is performed, and the specific steps are: lamination and pre-pressing are performed, and the lamination order is sodium metal negative electrode, electrolyte membrane and in-situ polymerized positive electrode. The electrolyte membrane is kept at 30μm. During the pre-pressing treatment, the pressure is set to 10-15MPa, the temperature is 90°C, and the time is 15-20min. Finally, the battery is packaged.

10. The method for preparing an all-solid-state sodium ion battery based on in-situ polymerization according to claim 1, characterized in that: In S5, battery testing is performed, including electrolyte characterization testing and battery performance testing, wherein the electrolyte characterization testing also includes ion conductivity testing and electrochemical window testing, and the battery performance testing also includes battery cycle performance testing and battery rate performance testing.

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