Solid-state electrolyte membrane and process for the preparation thereof

Abstract

This invention provides a solid electrolyte membrane and its preparation process, relating to the field of solid electrolyte technology. The solid electrolyte membrane has a core-skin structure consisting of a core layer and a skin layer. The core layer is made of polyethersulfone fiber, and the skin layer is composed of electrolyte particles. An adhesive exists between the core layer and the skin layer, adhering the electrolyte particles to the outer surface of the core layer. In this solid electrolyte membrane, the electrolyte particles are exposed, allowing for better performance of the electrolyte particles and resulting in high ionic conductivity.

Description

Technical Field

[0001] This invention belongs to the field of solid electrolyte technology and relates to a solid electrolyte membrane and its preparation process. Background Technology

[0002] Coaxial electrospinning is a novel process for preparing solid polymer electrolytes, which can effectively combine the polymer matrix and electrolyte to form a stable solid electrolyte membrane. Chinese patent CN119315210A discloses a sandwich-like fiber membrane prepared by triaxial electrospinning, comprising a core layer, an intermediate layer, and a shell layer, with the solid electrolyte located in the core layer. Chinese patent CN116024672A discloses a solid electrolyte comprising a composite of a fiber membrane and an electrolyte. The fiber membrane is composed of hollow fibers, each including a circumferential fiber wall and a hollow core portion. The fiber wall has a porous structure, and the electrolyte fills the hollow core portion and the porous structure of the fiber wall. In the above-mentioned prior art, although the polymer matrix can provide good support for the electrolyte, the electrolyte is located inside or encapsulated by the polymer matrix, hindering its movement and resulting in low ionic conductivity.

[0003] Solid-state electrolytes possess high ionic conductivity, which can reduce battery internal resistance, accelerate lithium-ion migration, and reduce polarization during charging and discharging, thereby improving discharge efficiency and rate performance. However, the ionic conductivity of existing solid-state electrolyte membranes is still insufficient. Therefore, the applicant believes that existing solid-state electrolyte membrane fabrication technologies require further improvement. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a solid electrolyte membrane and its preparation process.

[0005] The technical solution of the present invention is as follows:

[0006] A solid electrolyte membrane has a core-shell structure consisting of a core layer and a skin layer, wherein the core layer is a polyethersulfone fiber, the skin layer is an electrolyte particle, and an adhesive exists between the core layer and the skin layer to adhere the electrolyte particle to the outer surface of the core layer.

[0007] Preferably, the binder is a C8-C40 alkane containing mercapto or a C8-C40 substituted alkane containing mercapto.

[0008] More preferably, the binder is selected from C8-C30 alkyl thiols; The weight ratio of the binder to the electrolyte particles is 1:0.05-0.3.

[0009] Preferably, the thickness of the solid electrolyte membrane is 10-200 μm.

[0010] Preferably, the polyethersulfone fiber accounts for 40-80% of the weight of the solid electrolyte membrane, and the electrolyte particles account for 1-10% of the weight of the solid electrolyte membrane.

[0011] Preferably, the electrolyte particles are selected from one or a combination of two or more of oxide solid electrolytes, organic lithium salts, sulfide solid electrolytes, and chloride solid electrolytes.

[0012] A method for preparing a solid electrolyte membrane according to any of the above embodiments includes: Polyethersulfone is dissolved in an organic solvent to prepare solution A; The electrolyte particles and the binder are mixed evenly to form liquid B; Liquid A and liquid B are coaxially electrospun, with liquid A as the core layer and liquid B as the skin layer, to obtain the solid electrolyte membrane.

[0013] Preferably, the concentration of solution A is 15-40 wt%; The weight ratio of the electrolyte particles to the binder is 0.05-0.3:1.

[0014] Preferably, the organic solvent is selected from one or a combination of two or more of DMF, DMAc, NMP and DMSO.

[0015] Preferably, the inner needle diameter of the coaxial electrospinning is 0.8-2 mm, and the outer needle diameter is 3-5 times the inner needle diameter.

[0016] The beneficial effects of this invention are: (1) The solid electrolyte membrane of the present invention has a core-skin structure. The core layer is polyethersulfone fiber, which has high mechanical strength, good support capacity and good stability. The skin layer is electrolyte particles. The electrolyte particles are bonded to the outer surface of the skin layer by an adhesive, which has good stability. Since the electrolyte particles are not completely covered or encapsulated, at least some parts are exposed to the outside, which can give full play to the performance of the electrolyte. The solid electrolyte membrane has high ionic conductivity.

[0017] (2) The organic binder of the present invention uses alkane containing mercapto groups, which can play a bonding role while improving the hydrophobicity of the solid electrolyte membrane and improving the stability of the solid electrolyte membrane.

[0018] (3) The solid electrolyte membrane of the present invention can be prepared by coaxial electrospinning. The preparation technology is simple and can achieve low-cost large-scale preparation. Attached Figure Description

[0019] Figure 1 The image shows the AC impedance diagram of the solid electrolyte membrane obtained in Example 1.

[0020] Figure 2 The graph shows the electrochemical performance of the solid-state battery in Example 4.

[0021] Figure 3 This is a digital photograph of the solid electrolyte membrane of Example 5.

[0022] Figure 4 This is a TEM image of a single fiber of the solid electrolyte membrane in Example 5. Detailed Implementation

[0023] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0024] On the one hand, the present invention proposes a solid electrolyte membrane having a core-shell structure consisting of a core layer and a skin layer. The core layer is polyethersulfone fiber, the skin layer is electrolyte particles, and an adhesive exists between the core layer and the skin layer to adhere the electrolyte particles to the outer surface of the core layer.

[0025] This invention uses an adhesive to attach electrolyte particles to the outer surface of polyethersulfone fibers, forming a skin layer and a core layer of polyethersulfone fibers. The resulting solid electrolyte membrane has a skin-core structure, where only a portion of the exposed electrolyte particles is coated (the portion coated by the adhesive). Ion transport becomes point-to-point transport at the solid-solid interface, resulting in faster ion transport efficiency and better utilization of the conductivity of the electrolyte particles. The resulting solid electrolyte membrane has high ionic conductivity, approaching or reaching the ionic conductivity of the electrolyte particles.

[0026] In this invention, there are no particular limitations on the binder; the binder only needs to be able to firmly adsorb the electrolyte particles onto the surface of the polyethersulfone fiber. For example, the binder can be a polymer, such as polyvinylidene fluoride (PVDF), phenolic resin, polyacrylate, etc., or it can be a small molecule compound, such as an organic compound containing thiol groups. When a polymer is used as a binder, the polymer can be first dissolved in an organic solvent to form a polymer solution before being mixed and dispersed evenly with the electrolyte particles, or the polymer, organic solvent, and electrolyte particles can be mixed and dispersed together. When a small molecule compound is used as a binder, it can be directly mixed and dispersed without the need for an organic solvent, or the mixture can be heated to a certain temperature before mixing and dispersing evenly. Polymers, when used as binders, exhibit good encapsulation of electrolyte particles, resulting in fewer exposed electrolyte particles or a smaller proportion of exposed electrolyte particles on the solid electrolyte membrane. This provides some isolation for contact between electrolyte particles, leading to relatively low ionic conductivity. For example, the ionic conductivity of a solid electrolyte membrane can reach 70-80% of that of electrolyte particles (e.g., compressed sheets). Conversely, small molecule compounds, when used as binders, exhibit lower encapsulation of electrolyte particles, resulting in more exposed electrolyte particles or a higher proportion of exposed electrolyte particles on the solid electrolyte membrane. This also leads to relatively low ionic conductivity. For example, the ionic conductivity of a solid electrolyte membrane can reach 95% or more of that of electrolyte particles (e.g., compressed sheets).

[0027] In some embodiments, the binder is a C8-C40 alkane containing mercapto groups or a C8-C40 substituted alkane containing mercapto groups. Using the above technical solution, the binder is a small molecule compound containing mercapto groups. These mercapto groups can anchor both the electrolyte particles and the polyethersulfone fibers, thereby firmly adsorbing the electrolyte particles onto the outer surface of the polyethersulfone fibers. Furthermore, the binder has low encapsulation properties for the electrolyte particles, and the ionic conductivity of the solid electrolyte membrane can reach 95% or more of the ionic conductivity of the electrolyte particles (e.g., compressed into sheets).

[0028] For C8-C40 substituted alkanes containing thiol groups, they can be thiol-containing oxa-alkanes, thiol-containing ester-substituted alkanes, etc., such as trimethylolpropane tris(3-mercaptopropionate), bis(3-mercaptopropionic acid) ethylene glycol, 2-ethylhexyl 3-mercaptopropionate, etc.

[0029] In some embodiments, the binder is selected from C8-C30 alkyl thiols; The weight ratio of binder to electrolyte particles is 1:0.05-0.3.

[0030] The binder is further composed of C8-C30 alkyl thiols. Besides functioning as a thiol and a binder, the long-chain alkyl groups (C8-C30 alkyl groups) exhibit good hydrophobic properties, improving the hydrophobicity of the electrolyte particles. The solid electrolyte membrane can better isolate water vapor and enhance the stability of the electrolyte particles. Examples of C8-C30 alkyl thiols include n-octyl mercaptan, n-undecyl mercaptan, n-hexadecyl mercaptan, n-dodecyl mercaptan, and n-octadecyl mercaptan. For example, the weight ratio of binder to electrolyte particles can be any value or any value between 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, and 1:0.3, without any particular limitation.

[0031] In some embodiments, the thickness of the solid electrolyte membrane is 10-200 μm. For example, the thickness of the solid electrolyte membrane can be any value or any value between 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 160 μm, 180 μm, and 200 μm, without particular limitation. Further, the thickness of the solid electrolyte membrane can be 10-100 μm.

[0032] In some embodiments, the polyethersulfone fiber accounts for 40-80% of the weight of the solid electrolyte membrane, and the electrolyte particles account for 1-10% of the weight of the solid electrolyte membrane. For example, the weight percentage of polyethersulfone fiber in the solid electrolyte membrane can be any value or any value between 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc., without particular limitation; the weight percentage of electrolyte particles in the solid electrolyte membrane can be any value or any value between 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., without particular limitation.

[0033] In some embodiments, the electrolyte particles are selected from one or a combination of two or more of oxide solid electrolytes, organic lithium salts, sulfide solid electrolytes, and chloride solid electrolytes. For example, oxide solid electrolytes may be LLZO, LLTO, LATP, LAGP, LiPON, etc.; organic lithium salts may be lithium bis(oxalato)borate, lithium difluorooxalato)borate, lithium bis(difluorosulfonyl)imide, lithium bis(trifluoromethyl)sulfonyl)imide, lithium trifluoromethylsulfonate, lithium tri(trifluoromethyl)methyllithium, lithium trifluoromethylsulfinate, lithium difluorophosphate, etc.; and sulfide solid electrolytes may be β-Li3PS4, Li7P3S, etc. 11 Li6PS5Cl, Li 10 SnP2S 12Li4SnS4, Li2S, etc., and the chloride solid electrolyte can be Li3InCl6 and its dopants, Li3YCl6 and its dopants, Li2ZrCl6 and its dopants, etc., without any particular restrictions.

[0034] On the other hand, the present invention also provides a method for preparing a solid electrolyte membrane according to any of the above embodiments, comprising: Polyethersulfone is dissolved in an organic solvent to prepare solution A; Electrolyte particles and binder are mixed evenly to form solution B; Liquid A and liquid B are coaxially electrospun, with liquid A as the core layer and liquid B as the skin layer, to obtain a solid electrolyte membrane.

[0035] The solid electrolyte membrane of the present invention can be prepared by coaxial electrospinning. Solution A containing polyethersulfone is used to prepare the core layer, and solution B containing electrolyte particles and binder is used. The polyethersulfone material of the support layer has the advantages of high heat resistance and stable chemical properties. Moreover, the electrolyte particles are exposed outside the core layer (support layer), which is beneficial to improving ion transport performance.

[0036] When the binder is a polymer, an organic solvent can be added to solution B for dispersion. The organic solvent in solution B can be the same as or different from the organic solvent in solution A. For example, when the binder is polyvinylidene fluoride, the organic solvent used in solution B can be NMP, DMSO, DMF, DMAc, γ-butyrolactone, etc.

[0037] In some embodiments, the concentration of solution A is 15-40 wt%; The weight ratio of electrolyte particles to binder is 0.05-0.3:1.

[0038] For example, the concentration of solution A can be any value or any value between 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, etc., without any particular restriction; the weight ratio of electrolyte particles to binder can be any value or any value between 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, etc., without any particular restriction.

[0039] In some embodiments, the organic solvent is selected from one or a combination of two or more of DMF, DMAc, NMP and DMSO, which can effectively dissolve polyethersulfone and remove it by heating after film formation.

[0040] In some embodiments, the inner needle diameter of the coaxial electrospinning process is 0.8-2 mm, and the outer needle diameter is 3-5 times the inner needle diameter. For example, the inner needle diameter of the coaxial electrospinning process can be 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, etc., and the outer needle diameter can be 3 times, 3.2 times, 3.5 times, 4 times, 4.3 times, 4.5 times, 4.8 times, 5 times, etc., the same as the inner needle diameter; for example, if the inner needle diameter is 1 mm, the outer needle diameter can be 3 mm, 3.5 mm, 4 mm, 5 mm, etc.; for example, if the inner needle diameter is 1.5 mm, the outer needle diameter can be 5 mm, 5.5 mm, 6 mm, 7 mm, etc.

[0041] In this invention, there are no particular limitations on the specific process parameters for coaxial electrospinning. For example, the voltage can be 15-25V, the outer layer spinning speed can be 0.1-1mL / h, the inner layer spinning speed can be 0.5-2mL / h, and the distance from the spinning needle to the collector can be 30-50cm. After spinning, an anhydrous alcohol separator and a polymer electrolyte membrane can be used, and the obtained polymer electrolyte membrane is dried in a vacuum oven at 60℃.

[0042] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0043] Example 1 50g of polyethersulfone (Mw=500,000) was dissolved in DMF and magnetically stirred for 8 hours to obtain a spinning solution with a concentration of 30wt%, known as solution A. 4.8g of oxide electrolyte Li7La3Zr2O was added. 12 (LLZO) is dispersed in 24g of n-hexadecylthiol, which is solution B.

[0044] Solution A was transferred to the inner channel of the electrospinning solution, and solution B was transferred to the outer channel. A coaxial electrospinning needle was selected with an outer needle diameter of 5 mm and an inner needle diameter of 1.2 mm. The electrospinning parameters were adjusted as follows: voltage 18V, outer spinning speed 0.4 mL / h, inner spinning speed 0.8 mL / h, and distance from the spinning needle to the collector 30 cm. An anhydrous ethanol separator and electrolyte membrane were used, and the obtained electrolyte membrane was dried in a vacuum oven at 60 °C for 12 h to obtain a solid electrolyte membrane with a measured thickness of 50 μm.

[0045] The prepared solid electrolyte membrane was subjected to ionic conductivity testing. Steel sheet / / - steel sheet symmetrical coin cells were assembled in an argon-filled glove box, and the testing frequency range was 0.01~10. 5 Hz, amplitude 5mV, as shown in the attached image. Figure 1As shown, the ionic conductivity of the solid electrolyte membrane was measured to be 3.3 mS / cm, which is 97.1% of the ionic conductivity of the pressed pure LLZO powder.

[0046] The prepared solid electrolyte membrane was assembled into a solid-state battery. Using lithium metal as the negative electrode and lithium iron phosphate as the positive electrode, the solid-state battery was assembled in an argon-filled glove box. Constant current charge-discharge tests were conducted using a constant-temperature Xinwei testing system, with a voltage range of 2.0–3.75 V. The specific capacity of the solid-state battery at a 1C current density was 145 mAh / g (1C = 170 mA / g).

[0047] Example 2 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, solution B was adjusted to consist of 4.8g of oxide electrolyte LLZO dispersed in 24g of polyvinylidene fluoride and 80g of NMP. The remaining steps remained unchanged. The ionic conductivity of the obtained solid electrolyte membrane was measured to be 2.6 mS / cm, reaching 76.5% of the ionic conductivity of the pure LLZO powder obtained by tableting.

[0048] Following the method of Example 1, the solid-state battery prepared from the solid electrolyte membrane obtained in this example has a discharge specific capacity of 136 mAh / g at a current density of 1C (1C=170 mA / g).

[0049] Example 3 50 g of polyethersulfone (Mw = 500,000) was dissolved in DMAc and magnetically stirred for 8 h to obtain a spinning solution with a concentration of 22 wt%, which is solution A. With the ambient dew point controlled at -40 °C, 3.6 g of sulfide electrolyte Li6PS5Cl (LPSC, particle size 500 nm) was dispersed in 24 g of n-undecyl mercaptan, which is solution B.

[0050] Solution A was transferred to the inner channel of the electrospinning solution, and solution B was transferred to the outer channel. The outer diameter of the coaxial electrospinning needle was 4.8 mm, and the inner diameter was 1.5 mm. The electrospinning parameters were adjusted as follows: voltage 16V, outer spinning speed 0.6 mL / h, inner spinning speed 1.8 mL / h, and distance from the spinning needle to the collector 30 cm. Anhydrous ethanol was used to separate the collector and the electrolyte membrane, and the obtained electrolyte membrane was dried in a vacuum oven at 60℃ for 12 h to obtain a solid electrolyte membrane with a measured thickness of 20 μm.

[0051] The ionic conductivity of the solid electrolyte membrane obtained in this example was measured to be 4.7 mS / cm according to the method in Example 1, which is 97.9% of the ionic conductivity of the pressed pure LPSC powder.

[0052] The solid electrolyte membrane prepared above was assembled into a solid-state battery. Lithium metal was used as the negative electrode, and LiNi...0.8 Mn 0.1 Co 0.1 Solid-state batteries were assembled in an argon-filled glove box using O2 as the positive electrode. Constant-current charge-discharge tests were conducted using a constant-temperature Xinwei testing system, with a voltage range of 2.7-4.2V. The specific capacity of the solid-state battery at a 1C current density was 192.5 mAh / g (1C = 278 mA / g).

[0053] Example 4 50g of polyethersulfone (Mw=250,000) was dissolved in DMAc and magnetically stirred for 8 h to obtain a spinning solution with a concentration of 28wt%, designated as solution A. The ambient dew point was controlled at -40℃, and 5g of sulfide electrolyte Li... 10 GeP2S 12 (LGPS, particle size 1μm) is dispersed in 24g of n-undecyl mercaptan, which is solution B.

[0054] Solution A was transferred to the inner channel of the electrospinning solution, and solution B was transferred to the outer channel. A coaxial electrospinning needle was selected with an outer needle diameter of 4.8 mm and an inner needle diameter of 1.0 mm. The electrospinning parameters were adjusted as follows: voltage 20V, outer spinning speed 0.6 mL / h, inner spinning speed 1.8 mL / h, and distance from the spinning needle to the collector 30 cm. Anhydrous ethanol was used to separate the collector and the electrolyte membrane, and the obtained electrolyte membrane was dried in a vacuum oven at 60℃ for 12 h to obtain a solid electrolyte membrane with a measured thickness of 15 μm.

[0055] The ionic conductivity of the solid electrolyte membrane obtained in this example was measured to be 3.6 mS / cm according to the method in Example 1, which is 96% of the ionic conductivity of the pure LGPS powder in the tablet.

[0056] The solid electrolyte membrane prepared above was assembled into a solid-state battery. Using lithium metal as the negative electrode and lithium iron phosphate as the positive electrode, the solid-state battery was assembled in an argon-filled glove box. Constant current charge-discharge tests were conducted using a constant-temperature testing system with a voltage range of 2.0–3.75 V. The specific capacity of the solid-state battery at a 1C current density was 147.5 mAh / g (1C = 170 mA / g, see attached). Figure 2 (As shown).

[0057] Example 5 25g of polyethersulfone (Mw=500,000) was dissolved in DMAc and magnetically stirred for 8 hours to obtain a spinning solution with a concentration of 20wt%, designated as solution A. The ambient dew point was controlled at -40℃, and 5g of sulfide electrolyte Li... 5.3 PS 4.3 Cl 0.8 Br 0.7(LPSCB, particle size 500 nm) was dispersed in a mixture of 30g n-undecyl mercaptan and n-dodecyl mercaptan (weight ratio 1:1), which is solution B.

[0058] Solution A was transferred to the inner channel of the electrospinning solution, and solution B was transferred to the outer channel. A coaxial electrospinning needle was selected with an outer needle diameter of 2.4 mm and an inner needle diameter of 0.8 mm. The electrospinning parameters were adjusted as follows: voltage 22V, outer spinning speed 0.6 mL / h, inner spinning speed 1.8 mL / h, and distance from the spinning needle to the collector 30 cm. Anhydrous ethanol was used to separate the collector and the electrolyte membrane. The obtained electrolyte membrane was dried in a vacuum oven at 60℃ for 12 h to obtain a solid electrolyte membrane with a measured thickness of 100 μm. A digital photograph of the solid electrolyte membrane is attached. Figure 3 As shown in the attached figure, the TEM morphology of a single fiber of the solid electrolyte membrane is as follows. Figure 4 As shown.

[0059] The ionic conductivity of the solid electrolyte membrane obtained in this example was measured to be 3.0 mS / cm according to the method of Example 1, which is 96.8% of the ionic conductivity of the pressed pure LPSCB powder.

[0060] The solid electrolyte membrane prepared above was assembled into a solid-state battery. Using lithium metal as the negative electrode and lithium iron phosphate as the positive electrode, the solid-state battery was assembled in an argon-filled glove box. Constant current charge-discharge tests were conducted using a constant-temperature Xinwei testing system, with a voltage range of 2.0–3.75 V. The specific capacity of the solid-state battery at a 1C current density was 140 mAh / g (1C = 170 mA / g).

[0061] Example 6 25g of polyethersulfone (Mw=800,000) was dissolved in DMAc and magnetically stirred for 12h to obtain a spinning solution with a concentration of 20wt%, which is solution A. With the dew point controlled at -40℃, 5g of oxide electrolyte LiAlTi(PO4)3 (LATP, particle size 700 nm) was dispersed in a mixture of 30g of n-undecyl mercaptan and n-octyl mercaptan (weight ratio 7:3), which is solution B.

[0062] Solution A was transferred to the inner channel of the electrospinning solution, and solution B was transferred to the outer channel. The outer diameter of the coaxial electrospinning needle was 2.4 mm, and the inner diameter was 0.8 mm. The electrospinning parameters were adjusted as follows: voltage 22V, outer spinning speed 0.6 mL / h, inner spinning speed 1.8 mL / h, and distance from the spinning needle to the collector 30 cm. Anhydrous alcohol was used to separate the collector and the electrolyte membrane. The obtained electrolyte membrane was dried in a vacuum oven at 60℃ for 12 h and then rolled using a roller press at a pressure of 10 MPa to obtain a solid electrolyte membrane with a measured thickness of 10 μm.

[0063] The mechanical properties of the solid electrolyte membrane were tested using a tensile testing machine, and the mechanical strength was measured to be 10.2 MPa. It also maintained dimensional stability when heated to 245℃.

[0064] The ionic conductivity of the solid electrolyte membrane obtained in this example was measured to be 2.8 mS / cm according to the method in Example 1, which is 96.6% of the ionic conductivity of the compressed pure LATP powder.

[0065] The electrolyte membrane prepared above was assembled into a solid-state battery. Lithium metal was used as the negative electrode, and LiNi... 0.8 Mn 0.1 Co 0.1 Solid-state batteries were assembled in an argon-filled glove box using O2 as the positive electrode. Constant-current charge-discharge tests were conducted using a constant-temperature Xinwei testing system, with a voltage range of 2.7-4.2V. The specific capacity of the solid-state battery at a 1C current density was 185.2 mAh / g (1C = 278 mA / g).

[0066] Example 7 The difference between this embodiment and Example 6 is that in Example 6, the mixture of n-undecyl mercaptan and n-octyl mercaptan was replaced with an equal weight of trimethylolpropane tris(3-mercaptopropionate). The remaining steps remained unchanged. The ionic conductivity of the obtained solid electrolyte membrane was measured to be 2.5 mS / cm, reaching 86.2% of the ionic conductivity of the compressed pure LATP powder.

[0067] Following the method of Example 6, the solid-state battery prepared from the solid electrolyte membrane obtained in this example has a discharge specific capacity of 180 mAh / g at a current density of 1C (1C=278 mA / g).

[0068] Example 8 The difference between this embodiment and Example 6 is as follows: In Example 6, solution B was adjusted to: 5g LATP dispersed in 30g polyacrylate (Mw=21000, polymerized from methyl acrylate and butyl acrylate in a molar ratio of 1:2) and 100g butyl acetate. The remaining steps remained unchanged. The ionic conductivity of the obtained solid electrolyte membrane was measured to be 2.1 mS / cm, reaching 72.4% of the ionic conductivity of the pure LATP powder obtained by tableting.

[0069] Following the method of Example 6, the solid-state battery prepared from the solid electrolyte membrane obtained in this example has a discharge specific capacity of 178 mAh / g at a current density of 1C (1C = 278 mA / g).

[0070] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A solid electrolyte membrane, characterized in that, It has a core-shell structure consisting of a core layer and a skin layer, wherein the core layer is polyethersulfone fiber, the skin layer is electrolyte particles, and an adhesive exists between the core layer and the skin layer to adhere the electrolyte particles to the outer surface of the core layer.

2. The solid electrolyte membrane according to claim 1, characterized in that, The binder is a C8-C40 alkane containing mercapto or a C8-C40 substituted alkane containing mercapto.

3. The solid electrolyte membrane according to claim 2, characterized in that, The binder is selected from C8-C30 alkyl thiols; The weight ratio of the binder to the electrolyte particles is 1:0.05-0.

3.

4. The solid electrolyte membrane according to claim 1, characterized in that, The thickness of the solid electrolyte membrane is 10-200 μm.

5. The solid electrolyte membrane according to claim 1, characterized in that, The polyethersulfone fiber accounts for 40-80% of the weight of the solid electrolyte membrane, and the electrolyte particles account for 1-10% of the weight of the solid electrolyte membrane.

6. The solid electrolyte membrane according to claim 1, characterized in that, The electrolyte particles are selected from one or a combination of two or more of oxide solid electrolytes, organic lithium salts, sulfide solid electrolytes, and chloride solid electrolytes.

7. A method for preparing a solid electrolyte membrane according to any one of claims 1-6, characterized in that, include: Polyethersulfone is dissolved in an organic solvent to prepare solution A; The electrolyte particles and the binder are mixed evenly to form liquid B; Liquid A and liquid B are coaxially electrospun, with liquid A as the core layer and liquid B as the skin layer, to obtain the solid electrolyte membrane.

8. The method for preparing a solid electrolyte membrane according to claim 7, characterized in that, The concentration of solution A is 15-40 wt%; The weight ratio of the electrolyte particles to the binder is 0.05-0.3:

1.

9. The method for preparing a solid electrolyte membrane according to claim 7, characterized in that, The organic solvent is selected from one or a combination of two or more of DMF, DMAc, NMP and DMSO.

10. The method for preparing a solid electrolyte membrane according to claim 7, characterized in that, The inner needle diameter of the coaxial electrospinning is 0.8-2 mm, and the outer needle diameter is 3-5 times the inner needle diameter.

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