A hydrogenated solid electrolyte membrane, an all-solid-state battery and a preparation method thereof

Abstract

The present invention relates to the technical field of solid-state batteries, and discloses a hydride solid electrolyte membrane, an all-solid-state battery and a preparation method thereof. The raw materials of the hydride solid electrolyte membrane include: 80-95% of a hydride solid electrolyte, 5-15% of a hydroxyl-terminated polymer, and 0.1-10% of a binder. By combining the dehydrogenation bonding reaction and the bonding effect of the binder, the present invention effectively enhances the bonding force of each component in the hydride solid electrolyte membrane, improves the flexibility and mechanical strength of the electrolyte membrane, and reduces the pulverization and fragmentation phenomena caused by the change of internal stress in the solid-state battery during the cycling process, thereby improving the cycling performance of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a hydride solid electrolyte membrane, an all-solid-state battery and a preparation method thereof. Background Art

[0002] The solid electrolyte with high thermal stability can block the contact between the positive and negative electrodes and transport lithium ions, and can replace the separator and highly flammable electrolyte in the liquid battery to assemble an all-solid-state battery, thereby improving the energy density and thermal safety of the battery.

[0003] Currently, the density of conventional solid electrolytes is significantly higher than that of polymer separators and electrolytes, such as sulfide electrolytes, oxide electrolytes, and halide electrolytes. Therefore, solid electrolyte membranes have been widely studied. For example, a solid electrolyte membrane disclosed in Patent CN115498251A. To ensure the energy density advantage of the solid-state battery, the mass fraction of the solid electrolyte membrane in the solid-state battery should be as low as possible, that is, the thickness of the solid electrolyte membrane should be as thin as possible. However, the reduction of the electrolyte membrane thickness (<200 μm) will increase the possibility of electrolyte membrane cracking, which will further cause micro-short circuits in the solid-state battery, affecting the cycle performance and safety of the battery. Therefore, it is still necessary to provide a solid electrolyte membrane with the characteristics of low theoretical density, high mechanical strength, and good flexibility to ensure the processability and integratability of the solid electrolyte membrane and the high energy density characteristics of the solid-state battery.

[0004] The atomic mass of the elements constituting the hydride solid electrolyte is low, and it has the characteristic of low theoretical density. In particular, borohydride and carborane hydride solid electrolytes (for example, the theoretical density of LiBH4 is 0.68 g / cm 3 ) Based on the characteristic of low theoretical density, the mass of the hydride electrolyte is lower than that of sulfide, oxide, and halide electrolytes under the same thickness, which helps to reduce the mass fraction of the solid electrolyte in the solid-state battery and improve the energy density of the solid-state battery. However, in order to further improve the energy density of the solid-state battery, it is still necessary to solve the common problems of insufficient flexibility and mechanical strength of the solid electrolyte membrane at low thickness. Summary of the Invention

[0005] The present invention aims to overcome the problems of insufficient flexibility and mechanical strength of the solid electrolyte membrane in the prior art at low thickness, and provides a hydride solid electrolyte membrane, an all-solid-state battery and a preparation method thereof. By combining the dehydrogenation bonding reaction and the bonding effect of the binder, the binding force of each component in the hydride solid electrolyte membrane is effectively enhanced, the flexibility and mechanical strength of the electrolyte membrane are improved, and the pulverization and fragmentation phenomena caused by the change of internal stress in the solid-state battery during the cycle process are reduced, thereby improving the cycle performance of the battery.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a hydride solid electrolyte membrane. By mass percentage, the raw materials include: 80-95% of hydride solid electrolyte, 5-15% of hydroxyl-terminated polymer, and 0.1-10% of binder.

[0008] The hydroxyl-terminated polymer includes one or a combination of several of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polydimethylsiloxane, and hydroxyl-terminated polytetrahydrofuran.

[0009] The present invention selects hydride solid electrolyte as the main component of the solid electrolyte membrane. The atomic mass of the constituent elements of the hydride solid electrolyte is low, and it has the characteristic of low theoretical density. Its mass is lower than that of sulfide, oxide, and halide electrolytes under the same thickness, which helps to reduce the mass ratio of the solid electrolyte in the solid-state battery and improve the energy density of the solid-state battery. At the same time, the present invention also adds a hydroxyl-terminated polymer and a binder to the solid electrolyte membrane. Utilizing the characteristic that the negative hydrogen atoms of the hydride solid electrolyte and the positive hydrogen atoms of the hydroxyl-terminated polymer are prone to dehydrogenation and bonding reactions, the interaction between the hydride and the graft polymer is effectively strengthened. At the same time, combining the flexible characteristics of the graft polymer and the bonding effect of the binder, the flexibility and mechanical strength of the electrolyte membrane are effectively improved, and the pulverization and fragmentation phenomena caused by the change of internal stress in the solid-state battery during the cycling process are reduced, thereby improving the cycling performance of the battery.

[0010] Preferably, the hydride solid electrolyte includes one or a combination of several of borohydrides and their ion-substituted compounds, and carboranes.

[0011] Preferably, the binder includes one or a combination of several of styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene block copolymer, and styrene-ethylene-butene-styrene block copolymer.

[0012] In a second aspect, the present invention provides a preparation method of the above hydride solid electrolyte membrane, including the following steps:

[0013] (1) Add the hydride solid electrolyte to an inert solvent, mix evenly to obtain a first electrolyte slurry, and add the hydroxyl-terminated polymer to the first electrolyte slurry. After fully reacting and mixing evenly, a second electrolyte slurry is obtained;

[0014] (2) Add the binder to an inert solvent to obtain a glue solution, and then add the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry;

[0015] (3) Coating the third electrolyte slurry onto the surface of the substrate material, drying it, and performing isostatic pressing treatment to obtain the hydride solid electrolyte membrane as described above.

[0016] When preparing the solid electrolyte membrane of the present invention, isostatic pressing treatment can reduce the porosity of the electrolyte membrane, improve the density, contribute to the improvement of lithium ion transport, and at the same time increase the volumetric energy density of the all-solid-state battery.

[0017] Preferably, the inert solvents described in steps (1) and (2) include one or more of toluene, p-xylene, 1,3,5-trimethylbenzene, chlorobenzene, n-hexane, n-heptane, dichloromethane, and dichloroethane.

[0018] Preferably, the substrate material described in step (3) is one of copper foil, aluminum foil, stainless steel foil, PET substrate, PE substrate, PI substrate, PTFE substrate, and release paper.

[0019] Preferably, the drying temperature in step (3) is 40~120°C, and the drying time is 4~24 h; the pressure for isostatic pressing treatment is 100~600 MPa, and the pressure holding time is 5~60 min.

[0020] In a third aspect, the present invention provides an all-solid-state battery including the above hydride solid electrolyte membrane.

[0021] Preferably, both sides of the hydride solid electrolyte membrane are respectively adhered to the sides of the positive electrode plate and the negative electrode plate provided with the active material layer.

[0022] In a fourth aspect, the present invention provides a method for preparing the above all-solid-state battery, including the following steps:

[0023] A) Transferring the hydride solid electrolyte membrane to the side of the positive electrode plate or the negative electrode plate provided with the active material layer, and removing the substrate material to obtain the first battery inner core;

[0024] B) Adhering the positive electrode plate or the negative electrode plate to the hydride electrolyte membrane of the first battery inner core, and performing isostatic pressing treatment to obtain the second battery inner core;

[0025] C) Welding the positive and negative electrode tabs on the second battery inner core, and vacuum encapsulating with an aluminum-plastic film to obtain the all-solid-state battery.

[0026] Preferably, the transfer method in step A) is one of flat pressing, roll pressing, and isostatic pressing, and the transfer temperature is 20~80°C.

[0027] Therefore, the present invention has the following beneficial effects:

[0028] (1) The hydride solid electrolyte is selected as the main component of the solid electrolyte membrane, and its mass is lower than that of sulfide, oxide, and halide electrolytes under the same thickness, which helps to reduce the mass ratio of the solid electrolyte in the solid-state battery and improve the energy density of the solid-state battery.

[0029] (2) Hydroxyl-terminated polymers and binders are added to the solid electrolyte membrane. Utilizing the property that the negative hydrogen atoms of the hydride solid electrolyte and the positive hydrogen atoms of the hydroxyl-terminated polymer are prone to dehydrogenation and bonding reactions, the interaction between the hydride and the graft polymer is effectively strengthened. At the same time, combining the flexible characteristics of the graft polymer and the bonding effect of the binder effectively improves the flexibility and mechanical strength of the electrolyte membrane.

[0030] (3) Isostatic pressing treatment is carried out during the preparation of the solid electrolyte membrane, which can reduce the porosity of the electrolyte membrane and improve the density, helping to improve lithium-ion transport and simultaneously enhancing the volumetric energy density of the all-solid-state battery. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of the all-solid-state battery of the present invention; wherein, 1 - positive current collector; 2 - positive active material layer; 3 - hydride solid electrolyte membrane; 4 - negative active material layer; 5 - negative current collector.

[0032] Figure 2 is the first charge-discharge curve of the all-solid-state battery in Example 4 of the present invention; wherein, (a) charge curve; (b) discharge curve. Detailed Embodiments

[0033] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0034] In the present invention, unless otherwise specified, all devices and raw materials can be purchased from the market or are commonly used in this industry. The methods in the following embodiments, unless otherwise specified, are conventional methods in this field.

[0035] General Embodiment:

[0036] A hydride solid electrolyte membrane, in terms of mass percentage, the raw materials include: 80 - 95% of hydride solid electrolyte, 5 - 15% of hydroxyl-terminated polymer, and 0.1 - 10% of binder;

[0037] The hydroxyl-terminated polymer includes one or a combination of several of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polydimethylsiloxane, and hydroxyl-terminated polytetrahydrofuran.

[0038] As a specific embodiment, the thickness of the hydride solid electrolyte membrane is 50 - 150 μm.

[0039] As a specific embodiment, the hydride solid electrolyte includes one or a combination of several of borohydrides and their ionic substitution compounds, and carboranes; preferably, the borohydride is selected from LiBH4, LiB3H8, LiB 11 H 14 , Li2B 10 H 10 , Li2B 12 H 12 ; the ionic substitution compound of borohydride is selected from Li(BH4) a X 1-a (X = Cl and / or Br and / or I, 0 < a < 1), Li 7-b-c P (BH4) b S 6-b-c X c (X = Cl and / or Br and / or I, 0 < b < 2, 0 < c < 2), and the carborane is selected from LiCB9H 10 , LiCB 11 H 12 , LiCB 10 H 13 , LiC2B9H 12 .

[0040] As a specific embodiment, the binder includes one or a combination of several of styrene-butadiene rubber (SBR), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene block copolymer (SBS), and styrene-ethylene-butene-styrene block copolymer (SEBS); preferably, the binder is selected from SBR, PMMA, PTFE, and SEBS.

[0041] The preparation method of the above hydride solid electrolyte membrane includes the following steps:

[0042] (1) Add the hydride solid electrolyte to an inert solvent, mix evenly to obtain a first electrolyte slurry, and add a hydroxyl-terminated polymer to the first electrolyte slurry. After fully reacting and mixing evenly, a second electrolyte slurry is obtained;

[0043] (2) Add the binder to an inert solvent to obtain a glue solution, and then add the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry;

[0044] (3) Coat the third electrolyte slurry on the surface of the substrate material, dry it and perform isostatic pressing treatment to obtain the hydride solid electrolyte membrane.

[0045] As a specific embodiment, the inert solvents described in steps (1) and (2) include one or more of toluene, p-xylene, 1,3,5-trimethylbenzene, chlorobenzene, n-hexane, n-heptane, dichloromethane, and dichloroethane.

[0046] As a specific embodiment, the method of mixing evenly in step (1) is selected from one or more of mechanical stirring, mechanical vibration, ball milling, and ultrasonic dispersion, and the mixing time is 0.1 - 3 h.

[0047] As a specific embodiment, the substrate material described in step (3) is one of copper foil, aluminum foil, stainless steel foil, PET substrate, PE substrate, PI substrate, PTFE substrate, and release paper; preferably, the substrate material is one of aluminum foil, PET substrate, PTFE substrate, and release paper.

[0048] As a specific embodiment, the drying temperature in step (3) is 40 - 120 °C, and the drying time is 4 - 24 h; preferably, vacuum drying is used for the drying treatment, the drying temperature is 40 - 90 °C, and the drying time is 8 - 24 h.

[0049] As a specific embodiment, the pressure of the isostatic pressing treatment in step (3) is 100 - 600 MPa, and the pressure holding time is 5 - 60 min; preferably, the pressure of the isostatic pressing treatment is 100 - 300 MPa, and the pressure holding time is 5 - 30 min.

[0050] A all-solid-state battery comprising the above-mentioned hydride solid electrolyte membrane, as Figure 1 shown, includes a hydride solid electrolyte membrane 3, a positive electrode plate and a negative electrode plate respectively attached to both sides of the hydride solid electrolyte membrane. The positive electrode plate includes a positive current collector 1 and a positive active material layer 2 provided on the positive current collector, and the positive active material layer is attached to the hydride solid electrolyte membrane; the negative electrode plate includes a negative current collector 5 and a negative active material layer 4 provided on the negative current collector, and the negative active material layer is attached to the hydride solid electrolyte membrane.

[0051] The preparation method of the above all-solid-state battery includes the following steps:

[0052] A) Transfer the hydride solid electrolyte membrane to one side of the positive electrode plate or the negative electrode plate provided with the active material layer, and remove the substrate material to obtain the first battery inner core;

[0053] B) Attach the positive electrode plate or the negative electrode plate to the hydride electrolyte membrane of the first battery inner core, and perform isostatic pressing treatment to obtain the second battery inner core;

[0054] C) Weld the positive and negative electrode tabs on the second battery inner core, and vacuum package with an aluminum-plastic film to obtain the all-solid-state battery.

[0055] As a specific implementation manner, the transfer method in step A) is one of flat pressing, roll pressing, and isostatic pressing, and the transfer temperature is 20 to 80 °C.

[0056] Example 1:

[0057] A hydride solid electrolyte membrane is prepared by the following steps:

[0058] (1) Mix Li2B 12 H 12 with p-xylene evenly to obtain the first electrolyte slurry. Among them, the mass ratio of Li2B 12 H 12 to p-xylene is 22:78, and the mixing method is mechanical stirring for 1 h; Add monohydroxy-terminated polyethylene oxide (Maclean, Mn 600) to the evenly mixed first electrolyte slurry, and after full reaction and even mixing, obtain the second electrolyte slurry. Among them, the mass ratio of the first electrolyte slurry to the hydroxy-terminated polyethylene oxide is 100:2, and the mixing method is mechanical stirring for 3 h; Prepare a glue solution by mixing SBR and p-xylene at a mass ratio of 4:96, add the glue solution to the second electrolyte slurry and mix evenly to obtain the third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring for 1 h;

[0059] (2) Coating the third electrolyte slurry on a PET substrate by a wet coating method, vacuum drying at 80 °C for 8 h, and performing isostatic pressing treatment at 200 MPa for 10 min after drying to obtain a hydride solid electrolyte membrane with a thickness of 80 μm (Li2B 12 H 12 electrolyte membrane).

[0060] The above-prepared hydride solid electrolyte membrane is made into a all-solid-state battery, and the preparation steps are as follows:

[0061] A) Align the hydride solid electrolyte membrane (Li2B 12 H 12 electrolyte membrane), together with the substrate material (PET), with the negative electrode plate, and after flat pressing transfer at 70 °C, remove the substrate to obtain the first battery inner core; Among them, one side of the hydride solid electrolyte membrane is in contact with the active material layer side of the negative electrode plate; In the negative electrode active material layer, the negative electrode active material is silicon, the electrolyte is Li2B 12 H 12 , the conductive agent is carbon nanotube CNT, and the binder is SBR, with a mass ratio of 20:70:5:5; The time of flat pressing transfer is 3 min, and the pressure is 15 MPa.

[0062] B) Attach the positive electrode tab on one side of the hydride electrolyte membrane of the first battery inner core, and obtain the second battery inner core after isostatic pressing; among them, in the positive electrode active material layer, the positive electrode active material is NCM811, the electrolyte is Li6PS5Cl, the conductive agent is VGCF, and the binder is PVDF, with a mass ratio of 60:32:4:4; the isostatic pressing time is 10 min and the pressure is 400 MPa;

[0063] C) Weld the positive and negative electrode tabs on the second battery inner core, and vacuum package it with an aluminum-plastic film to obtain a all-solid-state battery.

[0064] Example 2:

[0065] A kind of hydride solid electrolyte membrane is prepared by the following steps:

[0066] (1) Mix Li2B 12 H 12 with p-xylene evenly to obtain the first electrolyte slurry. Among them, the mass ratio of Li2B 12 H 12 to p-xylene is 22:78, and the mixing method is mechanical ball milling, and the ball milling time is 1 h; add monohydroxy-terminated polydimethylsiloxane (Maclean, Mn 550) to the evenly mixed first electrolyte slurry, and obtain the second electrolyte slurry after fully reacting and mixing evenly. Among them, the mass ratio of the first electrolyte slurry to the hydroxy-terminated polydimethylsiloxane is 100:2, and the mixing method is ultrasonic dispersion, and the ultrasonic dispersion time is 3 h; prepare a glue solution with SBR and p-xylene at a mass ratio of 4:96, and add the glue solution to the second electrolyte slurry and mix evenly to obtain the third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring, and the stirring time is 1 h;

[0067] (2) Coating the third electrolyte slurry on the PET substrate by wet coating method, and vacuum drying at 80 °C for 8 h, and performing isostatic pressing treatment at 200 MPa for 10 min after drying to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0068] The prepared hydride solid electrolyte membrane is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0069] Example 3:

[0070] A kind of hydride solid electrolyte membrane is prepared by the following steps:

[0071] (1) Mix the hydride solid electrolyte with p-xylene evenly to obtain the first electrolyte slurry. Among them, the hydride solid electrolyte is LiBH4 and Li2B with a mass ratio of 1:2 12 H 12, the mass ratio of the hydride solid electrolyte to p-xylene is 22:78, the mixing method is mechanical ball milling, and the ball milling time is 1 h; mono-hydroxy-terminated polytetrahydrofuran (Macklin, Mn 650) is added to the uniform first electrolyte slurry, and after sufficient reaction and uniform mixing, a second electrolyte slurry is obtained. Among them, the mass ratio of the first electrolyte slurry to the hydroxy-terminated polytetrahydrofuran is 100:2, the mixing method is ultrasonic dispersion, and the ultrasonic dispersion time is 3 h; SBR and p-xylene are formulated into a glue solution with a mass ratio of 4:96, and the glue solution is added to the second electrolyte slurry and mixed evenly to obtain a third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring, and the stirring time is 1 h;

[0072] (2) Coating the third electrolyte slurry on a PET substrate by a wet coating method, vacuum drying at 80 °C for 8 h, and performing isostatic pressing treatment at 200 MPa for 10 min after drying to obtain a hydride solid electrolyte membrane with a thickness of 100 μm.

[0073] The prepared hydride solid electrolyte membrane is made into a all-solid-state battery, and the steps are the same as those in Example 1.

[0074] Example 4:

[0075] A hydride solid electrolyte membrane is prepared by the following steps:

[0076] (1) Mix Li(BH4) 0.75 I 0.25 with p-xylene to obtain a first electrolyte slurry. Among them, the mass ratio of Li(BH4) 0.75 I 0.25 to p-xylene is 22:78, the mixing method is mechanical ball milling, and the ball milling time is 1 h; a hydroxy-terminated polymer is added to the uniform first electrolyte slurry, and after sufficient reaction and uniform mixing, a second electrolyte slurry is obtained. Among them, the hydroxy-terminated polymer is a 1:1 mass ratio of mono-hydroxy-terminated polyethylene oxide (Macklin, Mn 600) and mono-hydroxy-terminated polydimethylsiloxane (Macklin, Mn 550), and the mass ratio of the first electrolyte slurry to the hydroxy-terminated polymer is 100:2, the mixing method is ultrasonic dispersion, and the ultrasonic dispersion time is 3 h; SBR and p-xylene are formulated into a glue solution with a mass ratio of 4:96, and the glue solution is added to the second electrolyte slurry and mixed evenly to obtain a third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring, and the stirring time is 1 h;

[0077] (2) Coating the third electrolyte slurry on a PET substrate by wet coating, and vacuum drying at 80 °C for 8 h, followed by isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 70 μm.

[0078] Fabricate a all-solid-state battery using the above-prepared hydride solid electrolyte membrane, the steps are the same as in Example 1; its first-cycle charge-discharge curve is as Figure 2 shown in

[0079] Example 5:

[0080] A hydride solid electrolyte membrane is prepared by the following steps:

[0081] (1) Mix LiCB 11 H 12 with 1,3,5-trimethylbenzene to obtain a first electrolyte slurry. Among them, the mass ratio of LiCB 11 H 12 to 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling for 0.5 h; Add monohydroxy-terminated polyethylene oxide (Maclean, Mn 600) to the uniformly mixed first electrolyte slurry, and after full reaction and uniform mixing, a second electrolyte slurry is obtained. Among them, the mass ratio of the first electrolyte slurry to hydroxy-terminated polydimethylsiloxane is 100:2.5, and the mixing method is mechanical stirring for 3 h; Prepare a glue solution with PMMA and 1,3,5-trimethylbenzene in a mass ratio of 2:98, add the glue solution to the second electrolyte slurry and mix uniformly to obtain a third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102.5:25, and the mixing method is mechanical stirring for 1 h;

[0082] (2) Coating the third electrolyte slurry on a PET substrate by wet coating, and vacuum drying at 60 °C for 12 h, followed by isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0083] Fabricate a all-solid-state battery using the above-prepared hydride solid electrolyte membrane, the steps are the same as in Example 1.

[0084] Example 6:

[0085] A hydride solid electrolyte membrane is prepared by the following steps:

[0086] (1) Mix LiCB 11 H 12 with 1,3,5-trimethylbenzene to obtain a first electrolyte slurry. Among them, the mass ratio of LiCB 11 H 12The mass ratio with 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling with a ball milling time of 0.5 h; in the homogeneous first electrolyte slurry, monohydroxy-terminated polyethylene oxide (Macklin, Mn 600) is added, and after sufficient reaction and uniform mixing, a second electrolyte slurry is obtained. Among them, the mass ratio of the first electrolyte slurry to the hydroxy-terminated polydimethylsiloxane is 100:2.5, and the mixing method is mechanical stirring with a stirring time of 3 h; SEBS and 1,3,5-trimethylbenzene are formulated into a glue solution at a mass ratio of 2:98, and the glue solution is added to the second electrolyte slurry and mixed uniformly to obtain a third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102.5:25, and the mixing method is mechanical stirring with a stirring time of 1 h;

[0087] (2)The third electrolyte slurry is coated on a PET substrate by a wet coating method, vacuum dried at 60 °C for 12 h, and then isostatically pressed at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0088] The prepared hydride solid electrolyte membrane is made into a all-solid-state battery, and the preparation steps are as follows:

[0089] A) Align the hydride solid electrolyte membrane together with the substrate material (PET) with the negative electrode plate, and after flat pressing and transferring at 70 °C, remove the substrate to obtain the first battery inner core; among them, one side of the hydride solid electrolyte membrane is in contact with the active material layer side of the negative electrode plate; in the negative electrode active material layer, the negative electrode active material is silicon, the electrolyte is Li2B 12 H 12 , the conductive agent is carbon nanotube CNT, the binder is SBR, and the mass ratio is 20:70:5:5; the time of flat pressing and transferring is 3 min, and the pressure is 15 MPa.

[0090] B) Attach the positive electrode plate on one side of the hydride electrolyte membrane of the first battery inner core, and after isostatic pressing, obtain the second battery inner core; among them, in the positive electrode active material layer, the positive electrode active material is NCM811, the electrolyte is Li3InCl6, the conductive agent is VGCF, the binder is PVDF, and the mass ratio is 60:32:4:4; the isostatic pressing time is 5 min, and the pressure is 550 MPa;

[0091] C) Weld the positive and negative electrode tabs on the second battery inner core, and vacuum package with an aluminum-plastic film to obtain a all-solid-state battery.

[0092] Comparative Example 1 (without adding hydroxy-terminated polymer in Example 1):

[0093] A hydride solid electrolyte membrane is prepared by the following steps:

[0094] (1) Mix Li₂B 12 H 12 uniformly with p - xylene to obtain the first electrolyte slurry. Among them, the mass ratio of Li₂B 12 H 12 to p - xylene is 22:78, and the mixing method is mechanical stirring for 1 h; Prepare a glue solution with SBR and p - xylene at a mass ratio of 4:96. Add the glue solution to the first electrolyte slurry and mix uniformly to obtain the second electrolyte slurry. Among them, the mass ratio of Li₂B 12 H 12 to SBR in the second electrolyte slurry is 96:4, and the mixing method is mechanical stirring for 1 h;

[0095] (2) Coat the second electrolyte slurry on the PET substrate by wet coating, and vacuum dry it at 80 °C for 8 h. After drying, perform isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0096] Make the obtained hydride solid electrolyte membrane into a all - solid - state battery, and the steps are the same as those in Example 1.

[0097] Comparative Example 2 (Example 1 without isostatic pressing treatment):

[0098] A hydride solid electrolyte membrane is prepared by the following steps:

[0099] (1) Mix Li₂B 12 H 12 uniformly with p - xylene to obtain the first electrolyte slurry. Among them, the mass ratio of Li₂B 12 H 12 to p - xylene is 22:78, and the mixing method is mechanical stirring for 1 h; Add monohydroxy - terminated polyethylene oxide (the same as in Example 1) to the uniformly mixed first electrolyte slurry. After fully reacting and mixing uniformly, obtain the second electrolyte slurry. Among them, the mass ratio of the first electrolyte slurry to hydroxy - terminated polyethylene oxide is 100:2, and the mixing method is mechanical stirring for 3 h; Prepare a glue solution with SBR and p - xylene at a mass ratio of 4:96. Add the glue solution to the second electrolyte slurry and mix uniformly to obtain the third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring for 1 h;

[0100] (2) Coat the third electrolyte slurry on the PET substrate by wet coating, and vacuum dry it at 80 °C for 8 h to obtain a hydride solid electrolyte membrane with a thickness of 120 μm.

[0101] The obtained hydride solid electrolyte membrane is made into a all-solid-state battery, and the steps are the same as those in Example 1.

[0102] Comparative Example 3 (the polymer in Example 2 is not hydroxy-terminated):

[0103] A hydride solid electrolyte membrane is prepared by the following steps:

[0104] (1) Mix Li2B 12 H 12 uniformly with p-xylene to obtain a first electrolyte slurry. Among them, the mass ratio of Li2B 12 H 12 to p-xylene is 22:78, and the mixing method is mechanical stirring for 1 h; add hydride-terminated polydimethylsiloxane (Macklin, Mn580) to the uniformly mixed first electrolyte slurry, and after fully reacting and mixing uniformly, a second electrolyte slurry is obtained. Among them, the mass ratio of the first electrolyte slurry to polyethylene oxide is 100:2, and the mixing method is mechanical stirring for 3 h; prepare a glue solution by mixing SBR and p-xylene at a mass ratio of 4:96, and add the glue solution to the second electrolyte slurry and mix uniformly to obtain a third electrolyte slurry. Among them, the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring for 1 h;

[0105] (2) Coating the third electrolyte slurry on a PET substrate by a wet coating method, vacuum drying at 80 °C for 8 h, and performing isostatic pressing treatment at 200 MPa for 10 min after drying to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0106] The obtained hydride solid electrolyte membrane is made into a all-solid-state battery, and the steps are the same as those in Example 1.

[0107] Comparative Example 4 (no hydroxy-terminated polymer is added in Example 5):

[0108] A hydride solid electrolyte membrane is prepared by the following steps:

[0109] (1) Mix LiCB 11 H 12 uniformly with 1,3,5-trimethylbenzene to obtain a first electrolyte slurry. Among them, the mass ratio of LiCB 11 H 12 to 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling for 0.5 h; prepare a glue solution by mixing PMMA and 1,3,5-trimethylbenzene at a mass ratio of 2:98, and add the glue solution to the first electrolyte slurry and mix uniformly to obtain a second electrolyte slurry. Among them, in the second electrolyte slurry, LiCB 11 H12 The mass ratio with PMMA is 98:2, the mixing method is mechanical stirring, and the stirring time is 1 h;

[0110] (2) Coating the second electrolyte slurry on the PET substrate by wet coating, vacuum drying at 60 °C for 12 h, and performing isostatic pressing at 200 MPa for 10 min after drying to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0111] Fabricate a all-solid-state battery with the above-prepared hydride solid electrolyte membrane, and the steps are the same as those in Example 1.

[0112] The raw materials and thicknesses of the hydride solid electrolyte membranes in the above examples and comparative examples are shown in Table 1.

[0113] Table 1: Raw materials of hydride solid electrolyte membrane

[0114]

[0115] Test the cycle performance of the all-solid-state batteries prepared in the above examples and comparative examples, and the results are shown in Table 2. The test temperature is 60 °C, the test current is 0.1 C, and the test pressure is 10 MPa.

[0116] Table 2: Test results of cycle performance of all-solid-state batteries

[0117]

[0118] Comparing Example 1 and Comparative Example 1, Example 5 and Comparative Example 4, it can be found that the introduction of the hydroxyl-terminated polymer in the examples of the present invention effectively improves the flexibility and mechanical strength of the hydride electrolyte membrane at low thickness, reduces the pulverization and fragmentation phenomena caused by the internal stress change of the solid-state battery during the cycle, thereby improving the cycle performance of the battery. The thickness of the electrolyte membrane can be reduced to a lower level on the premise of ensuring good cycle performance. At the same time, from the data comparison between Example 2 and Comparative Example 3, it can be seen that since the end group of polydimethylsiloxane is a hydrogen atom and is directly connected to the silicon atom, the electronegativity difference between the two atoms is small, and the degree of deviation of the shared electron pair is low. This end group does not interact / react with the hydride electrolyte, resulting in weak interaction force between the polymer and the hydride electrolyte and poor film-forming mechanical strength, thus leading to poor cycle stability.

[0119] Comparing Example 1 and Comparative Example 2, it can be found that by means of isostatic pressing, it is beneficial to reduce the thickness of the solid electrolyte membrane, effectively improve the density of the hydride electrolyte membrane, improve the ion transport efficiency, and thus improve the Coulomb efficiency and cycle capacity retention rate of the battery.

[0120] The above has introduced in detail a hydride solid electrolyte membrane, a preparation method thereof, and a manufacturing method of an all-solid-state battery provided by an embodiment of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application, and does not represent or limit the scope of the patent protection of the present invention. Based on the embodiments of the present invention, simple modifications made by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

Claims

1. A hydrogenated solid electrolyte membrane, characterized in that, In terms of mass percentage, the raw materials include: 80-95% of hydride solid electrolyte, 5-15% of hydroxyl-terminated polymer, and 0.1-10% of binder; The hydroxyl-terminated polymer includes one or a combination of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polydimethylsiloxane, and hydroxyl-terminated polytetrahydrofuran; The hydride solid electrolyte includes one or a combination of borohydrides and their ion-substituted compounds, and carboranes.

2. The hydrogenated solid electrolyte membrane according to claim 1, characterized in that, The binder includes one or a combination of styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene block copolymer, and styrene-ethylene-butene-styrene block copolymer.

3. A method for preparing a hydride solid electrolyte membrane as described in claim 1 or 2, characterized in that, It includes the following steps: (1) Add the hydride solid electrolyte to an inert solvent, mix evenly to obtain a first electrolyte slurry, and add the hydroxyl-terminated polymer to the first electrolyte slurry. After fully reacting and mixing evenly, a second electrolyte slurry is obtained; (2) Add the binder to an inert solvent to obtain a glue solution, and then add the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry; (3) Coating the third electrolyte slurry on the surface of the substrate material, drying and isostatic pressing to obtain the hydride solid electrolyte membrane.

4. The method for preparing a hydride solid electrolyte membrane according to claim 3, wherein The inert solvents described in steps (1) and (2) include one or several of toluene, p-xylene, 1,3,5-trimethylbenzene, chlorobenzene, n-hexane, n-heptane, dichloromethane, and dichloroethane.

5. The preparation method of the hydride solid electrolyte membrane according to claim 3, characterized in that, The substrate material described in step (3) is one of copper foil, aluminum foil, stainless steel foil, PET substrate, PE substrate, PI substrate, PTFE substrate, and release paper.

6. The method for preparing a hydride solid electrolyte membrane according to claim 3 or 5, characterized in that, The drying temperature in step (3) is 40-120 °C, and the drying time is 4-24 h; the pressure of the isostatic pressing treatment is 100-600 MPa, and the holding time is 5-60 min.

7. A all-solid-state battery, characterized in that, It includes the hydride solid electrolyte membrane described in claim 1 or 2, or the hydride solid electrolyte membrane prepared by the preparation method described in any one of claims 3-6.

8. The all-solid-state battery according to claim 7, characterized in that, Both sides of the hydride solid electrolyte membrane are respectively attached to the side of the positive electrode plate and the side of the negative electrode plate provided with the active material layer.

9. A method for preparing an all-solid-state battery as claimed in claim 7 or 8, characterized in that, It includes the following steps: A) Transfer the hydride solid electrolyte membrane to the side of the positive electrode plate or the negative electrode plate provided with the active material layer, and remove the substrate material to obtain a first battery inner core; B) Attach the positive electrode plate or the negative electrode plate to the hydride electrolyte membrane of the first battery inner core, and perform isostatic pressing treatment to obtain a second battery inner core; C) Weld the positive and negative electrode tabs on the second battery inner core, and vacuum package with an aluminum-plastic film to obtain the all-solid-state battery.

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