Hydride solid electrolyte membrane, all-solid-state battery and preparation method of all-solid-state battery

Abstract

The invention relates to the technical field of solid-state batteries, and discloses a hydride solid-state electrolyte membrane, an all-solid-state battery and a preparation method of the all-solid-state battery. The hydride solid electrolyte membrane comprises the following raw materials: 80-95% of a hydride solid electrolyte, 5-15% of a hydroxyl-terminated polymer and 0.1-10% of a binder. According to the hydride solid electrolyte membrane, the bonding force of all components in the hydride solid electrolyte membrane is effectively enhanced by combining the dehydrogenation bonding reaction with the bonding effect of the binder, the flexibility and mechanical strength of the electrolyte membrane are improved, the pulverization and fragmentation phenomena caused by the internal stress change of a solid battery in the circulation process are reduced, and the service life of the solid battery is prolonged. Therefore, the cycle performance of the battery is improved.

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] Solid electrolytes with high thermal stability have the function of blocking the contact between positive and negative electrodes and transmitting lithium ions. They can replace the separators and highly flammable electrolytes in liquid batteries and be assembled into all-solid-state batteries, thereby improving the energy density and thermal safety of the batteries.

[0003] At present, 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, so solid electrolyte membranes have been widely studied. For example, a solid electrolyte membrane disclosed in patent CN115498251A. In order to ensure the energy density advantage of solid-state batteries, the mass proportion of solid electrolyte membranes in solid-state batteries should be as low as possible, that is, the thickness of solid electrolyte membranes should be as thin as possible. However, the reduction in the thickness of the electrolyte membrane (<200μm) will increase the possibility of cracking of the electrolyte membrane, which will lead to micro-short circuits in solid-state batteries, affecting the cycle performance and safety of the battery. Therefore, it is still necessary to provide a solid electrolyte membrane that has the characteristics of low theoretical density, high mechanical strength, and good flexibility to ensure the processability and integration of the solid electrolyte membrane and the high energy density characteristics of solid-state batteries.

[0004] The atomic mass of the constituent elements of hydride solid electrolytes is low, and they have the characteristics of low theoretical density, especially borohydride and carborohydride solid electrolytes (such as LiBH4, which has a theoretical density of 0.68 g / cm 3 ). Based on the characteristics of low theoretical density, the mass of hydride electrolytes is lower than that of sulfide, oxide, and halide electrolytes at the same thickness, which helps to reduce the mass proportion of solid electrolytes in solid-state batteries and improve the energy density of solid-state batteries. However, in order to further improve the energy density of solid-state batteries, it is still necessary to solve the common problems of insufficient flexibility and mechanical strength of solid-state electrolyte membranes at low thickness. Summary of the invention

[0005] The present invention aims to overcome the problems of insufficient flexibility and mechanical strength of solid electrolyte membranes 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 with the bonding effect of the binder, the binding force of the components 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 caused by the internal stress changes of the solid-state battery during the cycle are reduced, thereby improving the cycle performance of the battery.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a hydride solid electrolyte membrane, wherein the raw materials include, by mass percentage: 80-95% hydride solid electrolyte, 5-15% hydroxyl-terminated polymer, and 0.1-10% binder; The hydroxyl-terminated polymer includes one or a combination of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polydimethylsiloxane, and hydroxyl-terminated polytetrahydrofuran.

[0007] The present invention uses 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. The mass is lower than that of sulfide, oxide, and halide electrolytes under the same thickness, which helps to reduce the mass proportion of solid electrolyte in solid-state batteries and improve the energy density of solid-state batteries. At the same time, the present invention also adds hydroxyl-terminated polymers and binders to the solid electrolyte membrane, and utilizes the characteristics that the negative hydrogen atoms of the hydride solid electrolyte and the positive hydrogen atoms of the hydroxyl-terminated polymer are prone to dehydrogenation bonding reactions, effectively strengthening the interaction between the hydride and the grafted polymer, and combining the flexible characteristics of the grafted polymer with the bonding effect of the binder, effectively improving the flexibility and mechanical strength of the electrolyte membrane, reducing the pulverization and fragmentation caused by the internal stress changes of the solid-state battery during the cycle, thereby improving the cycle performance of the battery.

[0008] Preferably, the hydride solid electrolyte includes one or a combination of borohydride and its ion-substituted compounds, and carborohydride.

[0009] Preferably, the binder comprises one or a combination of styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene block copolymer, styrene-ethylene-butylene-styrene block copolymer.

[0010] In a second aspect, the present invention provides a method for preparing the above-mentioned hydride solid electrolyte membrane, comprising the following steps: (1) adding a hydride solid electrolyte to an inert solvent and mixing them uniformly to obtain a first electrolyte slurry, adding a hydroxyl-terminated polymer to the first electrolyte slurry, reacting them sufficiently and mixing them uniformly to obtain a second electrolyte slurry; (2) adding a binder to an inert solvent to obtain a glue solution, and then adding the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry; (3) The third electrolyte slurry is coated on the surface of the base material, and the hydride solid electrolyte membrane is obtained after drying and isostatic pressing.

[0011] When preparing the solid electrolyte membrane of the present invention, isostatic pressing treatment can reduce the porosity of the electrolyte membrane, increase the density, help improve lithium ion transmission, and at the same time increase the volume energy density of the all-solid-state battery.

[0012] Preferably, the inert solvent in steps (1) and (2) includes one or more of toluene, p-xylene, 1,3,5-trimethylbenzene, chlorobenzene, n-hexane, n-heptane, dichloromethane and dichloroethane.

[0013] Preferably, the base material in step (3) is one of copper foil, aluminum foil, stainless steel foil, PET substrate, PE substrate, PI substrate, PTFE substrate and release paper.

[0014] Preferably, the drying temperature of 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.

[0015] In a third aspect, the present invention provides an all-solid-state battery comprising the above-mentioned hydride solid electrolyte membrane.

[0016] Preferably, both sides of the hydride solid electrolyte membrane are respectively bonded to one side of the positive electrode sheet and the negative electrode sheet provided with the active material layer.

[0017] In a fourth aspect, the present invention provides a method for preparing the above-mentioned all-solid-state battery, comprising the following steps: A) transferring the hydride solid electrolyte membrane to the side of the positive electrode sheet or the negative electrode sheet provided with the active material layer, removing the base material, and obtaining a first battery core; B) attaching a positive electrode sheet or a negative electrode sheet to the hydride electrolyte membrane of the first battery core, and performing isostatic pressing to obtain a second battery core; C) welding the positive and negative electrode tabs on the second battery core, and vacuum packaging with aluminum-plastic film to obtain the all-solid-state battery.

[0018] Preferably, the transfer method in step A) is one of flat plate pressing, roller pressing and isostatic pressing, and the transfer temperature is 20-80°C.

[0019] Therefore, the present invention has the following beneficial effects: (1) Hydride solid electrolyte is selected as the main component of the solid electrolyte membrane. Its mass is lower than that of sulfide, oxide, and halide electrolytes at the same thickness, which helps to reduce the mass proportion of solid electrolyte in solid-state batteries and improve the energy density of solid-state batteries; (2) Hydroxyl-terminated polymers and binders are added to the solid electrolyte membrane. The negative hydrogen atoms of the hydride solid electrolyte and the positive hydrogen atoms of the hydroxyl-terminated polymer are easily dehydrogenated to form bonds, which effectively strengthens the interaction between the hydride and the grafted polymer. At the same time, the flexibility of the grafted polymer and the bonding effect of the binder are combined to effectively improve the flexibility and mechanical strength of the electrolyte membrane. (3) Isostatic pressing during the preparation of solid electrolyte membranes can reduce the porosity of the electrolyte membranes and increase their density, which helps improve lithium ion transport and increase the volume energy density of all-solid-state batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the all-solid-state battery of the present invention; wherein, 1-positive electrode current collector; 2-positive electrode active material layer; 3-hydride solid electrolyte membrane; 4-negative electrode active material layer; 5-negative electrode current collector.

[0021] Figure 2 1 is the first cycle charge and discharge curve of the all-solid-state battery in Example 4 of the present invention; wherein, (a) is the charge curve; and (b) is the discharge curve. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art.

[0024] Overall embodiment: A hydride solid electrolyte membrane, wherein the raw materials include, by mass percentage: 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.

[0025] As a specific implementation, the thickness of the hydride solid electrolyte membrane is 50-150 μm.

[0026] As a specific embodiment, the hydride solid electrolyte includes one or a combination of borohydride and its ion-substituted compounds, and carborohydride; preferably, the borohydride is selected from LiBH4, LiB3H8, LiB 11 H 14 、Li2B 10 H 10 、Li2B 12 H12 ; The borohydride ion substitution compound 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), the carbohydride is selected from LiCB9H 10 、LiCB 11 H 12 、LiCB 10 H 13 、LiC2B9H 12 .

[0027] As a specific implementation, the binder includes one or a combination 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), styrene-ethylene-butylene-styrene block copolymer (SEBS); preferably, the binder is selected from SBR, PMMA, PTFE, SEBS.

[0028] The method for preparing the above-mentioned hydride solid electrolyte membrane comprises the following steps: (1) adding a hydride solid electrolyte to an inert solvent and mixing them uniformly to obtain a first electrolyte slurry, adding a hydroxyl-terminated polymer to the first electrolyte slurry, reacting them sufficiently and mixing them uniformly to obtain a second electrolyte slurry; (2) adding a binder to an inert solvent to obtain a glue solution, and then adding the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry; (3) The third electrolyte slurry is coated on the surface of the base material, and the hydride solid electrolyte membrane is obtained after drying and isostatic pressing.

[0029] As a specific implementation, the inert solvent in steps (1) and (2) includes one or more of toluene, p-xylene, 1,3,5-trimethylbenzene, chlorobenzene, n-hexane, n-heptane, dichloromethane, and dichloroethane.

[0030] As a specific implementation manner, the uniform mixing method in step (1) is selected from one or more of mechanical stirring, mechanical shaking, ball milling and ultrasonic dispersion, and the uniform mixing time is 0.1 to 3 hours.

[0031] As a specific implementation, the base 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 base material is one of aluminum foil, PET substrate, PTFE substrate, and release paper.

[0032] As a specific implementation, the drying temperature of step (3) is 40-120°C, and the drying time is 4-24 hours; preferably, the drying treatment is vacuum drying, the drying temperature is 40-90°C, and the drying time is 8-24 hours.

[0033] As a specific implementation manner, the pressure of the isostatic pressing treatment in step (3) is 100-600 MPa, and the holding time is 5-60 min; preferably, the pressure of the isostatic pressing treatment is 100-300 MPa, and the holding time is 5-30 min.

[0034] An all-solid-state battery comprising the above-mentioned hydride solid electrolyte membrane, such as Figure 1 As shown, it includes a hydride solid electrolyte membrane 3 and a positive electrode sheet and a negative electrode sheet respectively bonded to the two sides of the hydride solid electrolyte membrane, the positive electrode sheet includes a positive electrode collector 1 and a positive electrode active material layer 2 arranged on the positive electrode collector, and the positive electrode active material layer is bonded to the hydride solid electrolyte membrane; the negative electrode sheet includes a negative electrode collector 5 and a negative electrode active material layer 4 arranged on the negative electrode collector, and the negative electrode active material layer is bonded to the hydride solid electrolyte membrane.

[0035] The method for preparing the above-mentioned all-solid-state battery comprises the following steps: A) transferring the hydride solid electrolyte membrane to the side of the positive electrode sheet or the negative electrode sheet provided with the active material layer, removing the base material, and obtaining a first battery core; B) attaching a positive electrode sheet or a negative electrode sheet to the hydride electrolyte membrane of the first battery core, and performing isostatic pressing to obtain a second battery core; C) welding the positive and negative electrode tabs on the second battery core, and vacuum packaging with aluminum-plastic film to obtain the all-solid-state battery.

[0036] As a specific implementation manner, the transfer method in step A) is one of flat plate pressing, roller pressing, and isostatic pressing, and the transfer temperature is 20-80°C.

[0037] Embodiment 1: A hydride solid electrolyte membrane is prepared by the following steps: (1) Li2B 12 H 12 and p-xylene to obtain a first electrolyte slurry, wherein Li2B 12 H 12The mass ratio of SBR to p-xylene is 22:78, and the mixing method is mechanical stirring for 1 hour; monohydroxy-terminated polyethylene oxide (McLean, Mn 600) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein 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 hours; SBR and p-xylene are prepared into a glue solution at 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, wherein the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring for 1 hour; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 80°C for 8 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane (Li2B) with a thickness of 80 μm. 12 H 12 electrolyte membrane).

[0038] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the preparation steps are as follows: A) The hydride solid electrolyte membrane (Li2B 12 H 12 The electrolyte membrane) together with the base material (PET) is aligned with the negative electrode sheet, and the base material is removed after flat plate pressure transfer at 70°C to obtain the first battery core; wherein one side of the hydride solid electrolyte membrane is in contact with one side of the active material layer of the negative electrode sheet; in the negative electrode active material layer, the negative electrode active material is silicon, and the electrolyte is Li2B 12 H 12 The conductive agent is carbon nanotubes CNT, the binder is SBR, and the mass ratio is 20:70:5:5; the flat plate pressure transfer time is 3 minutes, and the pressure is 15 MPa.

[0039] B) attaching a positive electrode sheet to one side of the hydride electrolyte membrane of the first battery core, and isostatic pressing to obtain a second battery core; wherein, 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, and the mass ratio is 60:32:4:4; the isostatic pressing time is 10 min, and the pressure is 400 MPa; C) welding the positive and negative electrode tabs to the second battery core, and vacuum packaging with aluminum-plastic film to obtain an all-solid-state battery.

[0040] Embodiment 2: A hydride solid electrolyte membrane is prepared by the following steps: (1) Li2B 12 H12 and p-xylene to obtain a first electrolyte slurry, wherein Li2B 12 H 12 The mass ratio of SBR to p-xylene is 22:78, and the mixing method is mechanical ball milling, and the ball milling time is 1 hour; monohydroxy-terminated polydimethylsiloxane (McLean, Mn 550) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein 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 hours; SBR and p-xylene are prepared into a glue solution at 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, wherein 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 hour; (2) The third electrolyte slurry is coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h. After drying, it is subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0041] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0042] Embodiment 3: A hydride solid electrolyte membrane is prepared by the following steps: (1) The hydride solid electrolyte and p-xylene are uniformly mixed to obtain a first electrolyte slurry, wherein the hydride solid electrolyte is LiBH4 and Li2B in a mass ratio of 1:2. 12 H 12 , the mass ratio of the hydride solid electrolyte to p-xylene is 22:78, and the mixing method is mechanical ball milling for 1 hour; monohydroxyl-terminated polytetrahydrofuran (McLean, Mn 650) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the mass ratio of the first electrolyte slurry to the hydroxyl-terminated polytetrahydrofuran is 100:2, and the mixing method is ultrasonic dispersion, and the ultrasonic dispersion time is 3 hours; SBR and p-xylene are prepared into a glue solution at 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, wherein 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 hour; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 100 μm.

[0043] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0044] Embodiment 4: A hydride solid electrolyte membrane is prepared by the following steps: (1) Li(BH4) 0.75 I 0.25 and p-xylene to obtain a first electrolyte slurry, wherein Li(BH4) 0.75 I 0.25 The mass ratio of SBR to p-xylene is 22:78, and the mixing method is mechanical ball milling, and the ball milling time is 1 hour; a hydroxyl-terminated polymer is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the hydroxyl-terminated polymer is monohydroxy-terminated polyethylene oxide (McLean, Mn 600) and monohydroxy-terminated polydimethylsiloxane (McLean, Mn 550) in a mass ratio of 1:1, and the mass ratio of the first electrolyte slurry to the hydroxyl-terminated polymer is 100:2, and the mixing method is ultrasonic dispersion, and the ultrasonic dispersion time is 3 hours; SBR and p-xylene are prepared into a glue solution in 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, wherein 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 hour; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 70 μm.

[0045] The hydride solid electrolyte membrane prepared above was made into an all-solid-state battery, and the steps were the same as those in Example 1; its first cycle charge and discharge curve was as follows: Figure 2 as shown in .

[0046] Embodiment 5: A hydride solid electrolyte membrane is prepared by the following steps: (1) LiCB 11 H 12 and 1,3,5-trimethylbenzene to obtain a first electrolyte slurry, wherein LiCB 11 H 12The mass ratio of PMMA to 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling for 0.5 h; monohydroxy-terminated polyethylene oxide (McLean, Mn 600) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the mass ratio of the first electrolyte slurry to the hydroxy-terminated polydimethylsiloxane is 100:2.5, and the mixing method is mechanical stirring for 3 h; PMMA and 1,3,5-trimethylbenzene are prepared into a glue solution at a mass ratio of 2:98, and the glue solution is added to the second electrolyte slurry and mixed evenly to obtain a third electrolyte slurry, wherein 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; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 60° C. for 12 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0047] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0048] Embodiment 6: A hydride solid electrolyte membrane is prepared by the following steps: (1) LiCB 11 H 12 and 1,3,5-trimethylbenzene to obtain a first electrolyte slurry, wherein LiCB 11 H 12 The mass ratio of SEBS to 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling for 0.5h; monohydroxy-terminated polyethylene oxide (McLean, Mn 600) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the mass ratio of the first electrolyte slurry to the hydroxy-terminated polydimethylsiloxane is 100:2.5, and the mixing method is mechanical stirring for 3h; SEBS and 1,3,5-trimethylbenzene are prepared into a glue solution at a mass ratio of 2:98, and the glue solution is added to the second electrolyte slurry and mixed evenly to obtain a third electrolyte slurry, wherein the mass ratio of the second electrolyte slurry to the glue solution is 102.5:25, and the mixing method is mechanical stirring for 1h; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 60° C. for 12 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0049] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the preparation steps are as follows: A) Align the hydride solid electrolyte membrane with the substrate material (PET) and the negative electrode sheet, and remove the substrate after flat plate pressure transfer at 70°C to obtain the first battery core; wherein one side of the hydride solid electrolyte membrane is in contact with one side of the active material layer of the negative electrode sheet; in the negative electrode active material layer, the negative electrode active material is silicon, and the electrolyte is Li2B 12 H 12 The conductive agent is carbon nanotubes CNT, the binder is SBR, and the mass ratio is 20:70:5:5; the flat plate pressure transfer time is 3 minutes, and the pressure is 15 MPa.

[0050] B) attaching a positive electrode sheet to one side of the hydride electrolyte membrane of the first battery core, and isostatic pressing to obtain a second battery core; wherein, in the positive electrode active material layer, the positive electrode active material is NCM811, the electrolyte is Li3InCl6, the conductive agent is VGCF, and 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; C) welding the positive and negative electrode tabs to the second battery core, and vacuum packaging with aluminum-plastic film to obtain an all-solid-state battery.

[0051] Comparative Example 1 (Example 1 does not add hydroxyl-terminated polymer): A hydride solid electrolyte membrane is prepared by the following steps: (1) Li2B 12 H 12 and p-xylene to obtain a first electrolyte slurry, wherein Li2B 12 H 12 The mass ratio of SBR to p-xylene is 22:78, and the mixing method is mechanical stirring for 1 hour; the SBR and p-xylene are prepared into a glue solution at a mass ratio of 4:96, and the glue solution is added to the first electrolyte slurry and mixed evenly to obtain a second electrolyte slurry, wherein Li2B in the second electrolyte slurry 12 H 12 The mass ratio of SBR is 96:4, and the mixing method is mechanical stirring, and the stirring time is 1h; (2) The second electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0052] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0053] Comparative Example 2 (Example 1 is not subjected to isostatic pressing): A hydride solid electrolyte membrane is prepared by the following steps: (1) Li2B 12 H 12 and p-xylene to obtain a first electrolyte slurry, wherein Li2B 12 H 12 The mass ratio of SBR to p-xylene is 22:78, the mixing method is mechanical stirring, and the stirring time is 1h; monohydroxy-terminated polyethylene oxide (same as in Example 1) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the mass ratio of the first electrolyte slurry to the hydroxy-terminated polyethylene oxide is 100:2, and the mixing method is mechanical stirring, and the stirring time is 3h; SBR and p-xylene are prepared into a glue solution at 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, wherein 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 1h; (2) The third electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h to obtain a hydride solid electrolyte membrane with a thickness of 120 μm.

[0054] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0055] Comparative Example 3 (the polymer of Example 2 is not hydroxyl terminated): A hydride solid electrolyte membrane is prepared by the following steps: (1) Li2B 12 H 12 and p-xylene to obtain a first electrolyte slurry, wherein Li2B 12 H 12 The mass ratio of SBR to p-xylene is 22:78, and the mixing method is mechanical stirring for 1 hour; hydride-terminated polydimethylsiloxane (McLean, Mn580) is added to the uniform first electrolyte slurry, and the second electrolyte slurry is obtained after sufficient reaction and mixing, wherein the mass ratio of the first electrolyte slurry to polyethylene oxide is 100:2, and the mixing method is mechanical stirring for 3 hours; SBR and p-xylene are prepared into a glue solution at 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, wherein the mass ratio of the second electrolyte slurry to the glue solution is 102:25, and the mixing method is mechanical stirring for 1 hour; (2) The third electrolyte slurry is coated on a PET substrate by wet coating, and vacuum dried at 80° C. for 8 h. After drying, it is subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0056] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0057] Comparative Example 4 (Example 5 without adding hydroxyl-terminated polymer): A hydride solid electrolyte membrane is prepared by the following steps: (1) LiCB 11 H 12 and 1,3,5-trimethylbenzene to obtain a first electrolyte slurry, wherein LiCB 11 H 12 The mass ratio of PMMA to 1,3,5-trimethylbenzene is 22:78, and the mixing method is mechanical ball milling, and the ball milling time is 0.5h; PMMA and 1,3,5-trimethylbenzene are prepared into a glue solution with a mass ratio of 2:98, and the glue solution is added to the first electrolyte slurry and mixed evenly to obtain a second electrolyte slurry, wherein LiCB in the second electrolyte slurry 11 H 12 The mass ratio of MgO to PMMA was 98:2, and the mixing method was mechanical stirring for 1 h; (2) The second electrolyte slurry was coated on a PET substrate by wet coating, and vacuum dried at 60° C. for 12 h. After drying, it was subjected to isostatic pressing at 200 MPa for 10 min to obtain a hydride solid electrolyte membrane with a thickness of 80 μm.

[0058] The hydride solid electrolyte membrane prepared above is made into an all-solid-state battery, and the steps are the same as those in Example 1.

[0059] The raw materials and thicknesses of the hydride solid electrolyte membranes in the above-mentioned embodiments and comparative examples are shown in Table 1.

[0060] Table 1: Hydride solid electrolyte membrane raw materials

[0061] The cycle performance of the all-solid-state batteries prepared in the above embodiments and comparative examples was tested, and the results are shown in Table 2. The test temperature was 60° C., the test current was 0.1 C, and the test pressure was 10 MPa.

[0062] Table 2: All-solid-state battery cycle performance test results

[0063] By comparing Example 1 and Comparative Example 1, and Example 5 and Comparative Example 4, it can be found that the introduction of the hydroxyl-terminated polymer in the embodiment of the present invention effectively improves the flexibility and mechanical strength of the hydride electrolyte membrane under low thickness conditions, and reduces the pulverization and fragmentation caused by the internal stress changes 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 while ensuring good cycle performance. At the same time, it can be seen from the data comparison of Example 2 and Comparative Example 3 that since the end capping of polydimethylsiloxane is a hydrogen atom and is directly connected to the silicon atom, the difference in electronegativity between the two atoms is small, and the degree of displacement of the shared electron pair is low. The end capping does not interact / react with the hydride electrolyte, resulting in a weak interaction force between the polymer and the hydride electrolyte, poor film-forming mechanical strength, and thus poor cycle stability.

[0064] By comparing Example 1 and Comparative Example 2, it can be found that isostatic pressing is beneficial to reducing the thickness of the solid electrolyte membrane, effectively improving the density of the hydride electrolyte membrane, and improving the ion transfer efficiency, thereby improving the coulombic efficiency and cycle capacity retention rate of the battery.

[0065] The above is a detailed introduction to a hydride solid electrolyte membrane, a preparation method and an all-solid-state battery manufacturing method provided in the embodiments 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 protection of the present invention. Based on the embodiments of the present invention, simple modifications made to the present invention by those skilled in the art without making creative work are all within the scope of protection of the present invention.

Claims

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

2. The hydride solid electrolyte membrane according to claim 1, characterized in that: The hydride solid electrolyte includes one or a combination of borohydride, its ion-substituted compound, and carborohydride.

3. The hydride solid electrolyte membrane according to claim 2, 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, styrene-ethylene-butylene-styrene block copolymer.

4. A method for preparing a hydride solid electrolyte membrane according to any one of claims 1 to 3, characterized in that: The steps include: (1) adding a hydride solid electrolyte to an inert solvent and mixing them uniformly to obtain a first electrolyte slurry, adding a hydroxyl-terminated polymer to the first electrolyte slurry, reacting them sufficiently and mixing them uniformly to obtain a second electrolyte slurry; (2) adding a binder to an inert solvent to obtain a glue solution, and then adding the glue solution to the second electrolyte slurry to obtain a third electrolyte slurry; (3) The third electrolyte slurry is coated on the surface of the base material, and the hydride solid electrolyte membrane is obtained after drying and isostatic pressing.

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

6. The method for preparing a hydride solid electrolyte membrane according to claim 4, 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.

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

8. An all-solid-state battery, characterized in that: Comprising the hydride solid electrolyte membrane as described in any one of claims 1 to 3 or the hydride solid electrolyte membrane prepared by the preparation method as described in any one of claims 4 to 7.

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

10. A method for preparing an all-solid-state battery as claimed in claim 8 or 9, characterized in that: The steps include: A) transferring the hydride solid electrolyte membrane to the side of the positive electrode sheet or the negative electrode sheet provided with the active material layer, removing the base material, and obtaining a first battery core; B) attaching a positive electrode sheet or a negative electrode sheet to the hydride electrolyte membrane of the first battery core, and performing isostatic pressing to obtain a second battery core; C) welding the positive and negative electrode tabs on the second battery core, and vacuum packaging with aluminum-plastic film to obtain the all-solid-state battery.

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