Preparation method of high-stability halide solid-state battery

Abstract

The invention discloses a preparation method of a high-stability halide solid-state battery, a Li3YCl6 electrolyte is modified by adopting an AlCl3-ZrF4-LiCl ternary synergistic doping system, an ion transmission channel is regulated and controlled through precise lattice substitution of Al < 3 + >, the substitution rate can reach 12%, the fluorine-chlorine synergistic effect of ZrF4 and LiCl can optimize mechanical properties and electrochemical stability, and the high-stability halide solid-state battery is prepared. High conductivity, high toughness and high voltage resistance of the electrolyte are realized, a difunctional composite intermediate medium formed by Li2SiO3 and VF5 is matched, Li2SiO3 provides a continuous channel for Li < + > transmission, VF5 is used as an interface reaction active center, and an interface enrichment effect formed by Zr < 4 + > in ternary synergistic doping is combined, so that the content of Zr element on an interface is 3.5 times that of a body, and a Li4SiO4-LiF-V2O5 composite interface layer with a three-dimensional network structure is generated. According to the in-situ interface layer, the Ni < 2 + > diffusion coefficient can be reduced to 8.2 * 10 <-16 > cm < 2 > / s from 10 <-13 > cm < 2 > / s, meanwhile, the interface impedance can be as low as 78 omega cm < 2 >, the preparation process is high in compatibility, the sol-gel coating and low-temperature hot pressing processes are easy to popularize on a large scale, the in-situ interface layer does not need additional synthesis steps, and the battery preparation cost is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the field of solid-state batteries, in particular to a preparation method of a high-stability halide solid-state battery. BACKGROUND

[0002] Under the dual demands of increasing the cruising range of new energy vehicles and expanding the capacity of large-scale energy storage systems, the battery energy density needs to break through the threshold of 350 Wh / kg, the cycle life needs to meet more than 1500 times of charge and discharge cycles, and the safety needs to completely avoid the risk of thermal runaway. NCM622 high-nickel positive electrode material has become a core electrode material for building a high-energy-density battery system because the theoretical specific capacity reaches 190 mAh / g and the working voltage platform is stable at 3.8 V. However, in actual application, the interface compatibility problem of the NCM622 positive electrode and the electrolyte is highlighted: during the charging and discharging process, the Li2O active phase is easily precipitated in the delithiation area on the surface of the positive electrode, and an interface reaction occurs with the halide electrolyte to generate a high-impedance Y-O-Cl phase; at the same time, the diffusion coefficient of the Ni 2+ / Co 3+ transition metal ion is as high as 10-13 cm 2 / s, which is easy to be embedded into the electrolyte lattice to block the Li+ transport channel, and finally the capacity attenuation rate exceeds 20% after 50 cycles of the battery. In addition, the traditional Li3YCl6 halide electrolyte has inherent defects, the room-temperature ionic conductivity is only 1.1 x 10 -3 S•cm -1 , the fracture toughness is less than 0.25 MPa•m 1 / 2 , and the electrochemical window is limited to below 4.2 V, which cannot meet the charging cut-off voltage requirement of 4.3-4.5 V of the NCM622 positive electrode.

[0003] To solve the above problems, the prior art mostly adopts a single doping modification or interface coating strategy. For example, AlCl3 is doped to improve the ionic conductivity of the halide electrolyte, but the mechanical toughness is limitedly improved; or a Li2SiO3 insulating layer is coated on the surface of the positive electrode to block the ion diffusion, but the interface impedance is significantly increased. The single technical solution cannot simultaneously achieve the dual targets of "high-conductivity and high-toughness of the electrolyte + low-impedance and stability of the interface", so that the comprehensive performance of the battery is difficult to break through, which limits the large-scale application of the NCM622 positive electrode in the solid-state battery. Therefore, it is necessary to propose a new scheme to simultaneously achieve the high-conductivity and high-toughness of the electrolyte and the low-impedance and stability of the interface. SUMMARY

[0004] In view of the above, the present application aims to solve the problem that the prior art cannot simultaneously achieve the high-conductivity and high-toughness of the electrolyte and the low-impedance and stability of the interface, and the main purpose is to provide a preparation method of a high-stability halide solid-state battery.

[0005] To achieve the above object, the application adopts the following technical solutions: A preparation method of a high-stability halide solid-state battery, comprising the following steps: (1) Preparation of a composite solid-state electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl are weighed according to a mass ratio of (85-95):(1-5):(2-8):(1-3), mixed in an argon glove box by using a planetary mixer at a rotating speed of 300-500 rpm for 30-60 min to obtain a mixed powder, the mixed powder is transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 DEG C at a heating rate of 1-5 DEG C / min, and kept sintering for 4-9 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block, the sintered block is placed in a agate ball mill jar, ethanol is used as a dispersion medium, and ball milling is performed for 2 h to obtain an electrolyte powder, the electrolyte powder is loaded into a mold, the loading thickness is 200 mu m, the mold is transferred to a cold isostatic pressing machine, and pressing is performed at a pressure of 100-120 Mpa for 30-90 min to obtain a composite solid-state electrolyte; (2) Preparation of a composite positive electrode: Li2SiO3 powder is dispersed in ethanol, and after ultrasonic treatment for 30 min, VF5 is added, the mass ratio of Li2SiO3 powder to VF5 is 6:4, and after stirring, a uniform sol is formed, the sol is coated on the surface of an NCM622 positive electrode sheet, then transferred to a vacuum drying oven and heated to 80-90 DEG C, and dried for 2 h, and then transferred to a program-controlled temperature furnace and heated to 150 DEG C at a heating rate of 1-5 DEG C / min, and annealed for 1 h to form a composite intermediate medium layer with a thickness of 40-90 nm, thereby obtaining a composite positive electrode; (3) Battery assembly: in an argon glove box, a first current collector, a lithium metal negative electrode, a composite solid-state electrolyte, a composite positive electrode and a second current collector are sequentially stacked in a mold, pre-pressing is performed at room temperature and a pressure of 3 MPa for 5 min, then heated to 80 DEG C and pressurized to 5 MPa, and kept at a temperature and pressure for 10 min to obtain a laminated body, finally, the laminated body is packaged by using an aluminum-plastic composite film by using a vacuum packaging machine, thereby obtaining a solid-state battery.

[0006] As a preferred solution, in step (1), the water and oxygen content of the argon glove box is ≤0.1 ppm.

[0007] As a preferred solution, in step (3), the water and oxygen content of the argon glove box is ≤0.1 ppm.

[0008] As a preferred solution, in step (3), the first current collector is a copper foil, and the second current collector is an aluminum foil.

[0009] As a preferred solution, in step (3), the vacuum degree of the vacuum packaging machine is -0.095 MPa.

[0010] As a preferred solution, in step (3), the thickness of the lithium metal negative electrode is 50 μm.

[0011] Compared with the prior art, the present application has obvious advantages and beneficial effects, and specifically, from the above technical solution, it can be known that: By using the AlCl3-ZrF4-LiCl ternary synergistic doping system to modify the Li3YCl6 electrolyte, the ion transmission channel is regulated through the precise lattice substitution of Al 3+ , and the substitution rate can reach 12%, the fluorine-chlorine synergistic effect of ZrF4 and LiCl can optimize the mechanical properties and electrochemical stability, realize high conductivity, high toughness and high pressure resistance of the electrolyte, and further combine the double functional composite intermediate medium formed by Li2SiO3 and VF5, Li2SiO3 provides a continuous channel for Li+ transmission, VF5 acts as an interface reaction active center, and the interface enrichment effect formed by Zr 4+ in the ternary synergistic doping makes the content of Zr element on the interface 3.5 times of the bulk, which guides the generation of the Li4SiO4-LiF-V2O5 composite interface layer with three-dimensional network structure, and the interface layer can reduce the Ni2+ diffusion coefficient from 10 - 13 cm 2 / s to 8.2×10 -16 cm 2 / s, and the interface impedance can be as low as 78 Ω•cm 2 , and the preparation process has strong compatibility, the sol-gel coating and low-temperature hot pressing process are easy to scale up, and the in-situ interface layer does not need additional synthesis steps, which reduces the battery preparation cost.

[0012] In order to more clearly illustrate the structural features and effects of the present application, the present application will be described in detail below in combination with specific embodiments. DETAILED DESCRIPTION

[0013] The present application discloses a preparation method of a high-stability halide solid-state battery, comprising the following steps: (1) Preparation of the composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl are weighed according to the mass ratio of (85-95):(1-5):(2-8):(1-3), mixed in an argon glove box for 30-60 min at a rotation speed of 300-500 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550°C at a heating rate of 1-5°C / min, and then sintered for 4-9 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block. The sintered block is placed in a agate ball mill jar, ethanol is used as the dispersion medium, and ball milling is performed for 2 h to obtain an electrolyte powder. The electrolyte powder is loaded into a mold, the powder thickness is 200 μm, and the mold is transferred to a cold isostatic pressing machine and pressed at a pressure of 100-120 MPa for 30-90 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box is ≤0.1 ppm.

[0014] (2) Preparation of the composite positive electrode: Li2SiO3 powder is dispersed in ethanol, and after ultrasonic treatment for 30 min, VF5 is added, and the mass ratio of Li2SiO3 powder to VF5 is 6:4. After stirring, a uniform sol is formed, which is coated on the surface of an NCM622 positive electrode sheet. Then, the coated sheet is transferred to a vacuum drying oven and heated to 80-90°C, and dried for 2 h. Subsequently, the sheet is transferred to a program-controlled furnace and heated to 150°C at a heating rate of 1-5°C / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 40-90 nm, thereby obtaining a composite positive electrode.

[0015] (3) Battery assembly: In an argon glove box, a first current collector, a lithium metal negative electrode, a composite solid electrolyte, a composite positive electrode, and a second current collector are stacked in a mold in the order of first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector. First, pre-pressing is performed at room temperature and a pressure of 3 MPa for 5 min, and then the temperature is increased to 80°C and the pressure is increased to 5 MPa, and then the temperature and pressure are maintained for 10 min to obtain a stacked body. Finally, the stacked body is packaged using an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery. The water and oxygen content of the argon glove box is ≤0.1 ppm, the first current collector is a copper foil, the second current collector is an aluminum foil, the vacuum degree of the vacuum packaging machine is -0.095 MPa, and the thickness of the lithium metal negative electrode is 50 μm.

[0016] The following examples are used to illustrate the application in detail.

[0017] Example 1 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to a mass ratio of 90:3:5:2, mixed in an argon glove box for 45 min at a rotation speed of 400 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 3 ℃ / min, and then sintered for 6 h, and then naturally cooled to room temperature in the furnace. The sintered block was placed in an agate ball mill jar, ethanol was used as the dispersion medium, and ball milling was performed for 2 h to obtain electrolyte powder. The electrolyte powder was loaded into a mold with a powder thickness of 200 μm, and then transferred to a cold isostatic pressing machine for pressing at a pressure of 110 MPa for 60 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box was ≤0.1 ppm.

[0018] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and then VF5 was added after ultrasonic treatment for 30 min. The mass ratio of Li2SiO3 powder to VF5 was 6:4. After stirring, a uniform sol was formed. The sol was coated on the surface of an NCM622 positive electrode sheet. Then, the coated sheet was transferred to a vacuum drying oven and heated to 85 ℃, and then dried for 2 h. Subsequently, the sheet was transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 3 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 50 nm, thereby obtaining a composite positive electrode.

[0019] (3) Battery assembly: In an argon glove box, a first current collector, a lithium metal negative electrode, a composite solid electrolyte, a composite positive electrode, and a second current collector were sequentially stacked in a mold. First, pre-pressing was performed at room temperature and a pressure of 3 MPa for 5 min. Then, the temperature was increased to 80 ℃ and the pressure was increased to 5 MPa, and then the temperature and pressure were maintained for 10 min to obtain a stacked body. Finally, the stacked body was packaged using an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery. The water and oxygen content of the argon glove box was ≤0.1 ppm. The first current collector was a copper foil, and the second current collector was an aluminum foil. The vacuum degree of the vacuum packaging machine was -0.095 MPa. The thickness of the lithium metal negative electrode was 50 μm.

[0020] Example 2 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to a mass ratio of 90:3:5:2, mixed in an argon glove box for 45 min at a rotation speed of 400 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 3 ℃ / min, and then sintered for 6 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block. The sintered block was placed in an agate ball mill jar, ethanol was used as a dispersion medium, and ball milling was performed for 2 h to obtain electrolyte powder. The electrolyte powder was loaded into a mold, the powder thickness was 200 μm, the mold was transferred to a cold isostatic pressing machine, the pressure was 110 MPa, and the pressing time was 60 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box was ≤0.1 ppm.

[0021] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and VF5 was added after ultrasonic treatment for 30 min. The mass ratio of Li2SiO3 powder to VF5 was 6:4. After stirring, a uniform sol was formed. The sol was coated on the surface of the NCM622 positive electrode sheet. Then, it was transferred to a vacuum drying oven and heated to 85 ℃, and dried for 2 h. Subsequently, it was transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 3 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 40 nm, thereby obtaining a composite positive electrode.

[0022] (3) Battery assembly: In an argon glove box, the first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector were stacked in the mold in the above order. First, pre-pressing was performed at room temperature and a pressure of 3 MPa for 5 min. Then, the temperature was increased to 80 ℃ and the pressure was increased to 5 MPa, and then the temperature and pressure were maintained for 10 min to obtain a stacked body. Finally, the stacked body was packaged with an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery. The water and oxygen content of the argon glove box was ≤0.1 ppm. The first current collector was a copper foil, and the second current collector was an aluminum foil. The vacuum degree of the vacuum packaging machine was -0.095 MPa. The thickness of the lithium metal negative electrode was 50 μm.

[0023] Example 3 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to a mass ratio of 90:3:5:2, mixed in an argon glove box for 45 min at a rotation speed of 400 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 3 ℃ / min, and then sintered for 6 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block. The sintered block was placed in an agate ball mill jar, ethanol was used as a dispersion medium, and ball milling was performed for 2 h to obtain electrolyte powder. The electrolyte powder was loaded into a mold, the powder thickness was 200 μm, the mold was transferred to a cold isostatic pressing machine, the pressure was 110 MPa, and the pressing time was 60 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box was ≤0.1 ppm.

[0024] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and VF5 was added after ultrasonic treatment for 30 min. The mass ratio of Li2SiO3 powder to VF5 was 6:4. After stirring, a uniform sol was formed. The sol was coated on the surface of the NCM622 positive electrode sheet. Then, it was transferred to a vacuum drying oven and heated to 85 ℃, and dried for 2 h. Subsequently, it was transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 3 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 60 nm, thereby obtaining a composite positive electrode.

[0025] (3) Battery assembly: In an argon glove box, the first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector were stacked in the mold in the above order. First, pre-pressing was performed at room temperature and a pressure of 3 MPa for 5 min. Then, the temperature was increased to 80 ℃ and the pressure was increased to 5 MPa, and then the temperature and pressure were maintained for 10 min to obtain a stacked body. Finally, the stacked body was packaged with an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery. The water and oxygen content of the argon glove box was ≤0.1 ppm. The first current collector was a copper foil, and the second current collector was an aluminum foil. The vacuum degree of the vacuum packaging machine was -0.095 MPa. The thickness of the lithium metal negative electrode was 50 μm.

[0026] Example 4 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to a mass ratio of 90:3:5:2, mixed in an argon glove box for 45 min at a rotation speed of 400 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 3 ℃ / min, and then sintered for 6 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block. The sintered block was placed in an agate ball mill jar, ethanol was used as a dispersion medium, and ball milling was performed for 2 h to obtain electrolyte powder. The electrolyte powder was loaded into a mold, the powder thickness was 200 μm, the mold was transferred to a cold isostatic pressing machine, the pressure was 110 MPa, and the pressing time was 60 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box was ≤0.1 ppm.

[0027] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and VF5 was added after ultrasonic treatment for 30 min. The mass ratio of Li2SiO3 powder to VF5 was 6:4. After stirring, a uniform sol was formed. The sol was coated on the surface of the NCM622 positive electrode sheet. Then, it was transferred to a vacuum drying oven and heated to 85 ℃, and dried for 2 h. Subsequently, it was transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 3 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 90 nm, thereby obtaining a composite positive electrode.

[0028] (3) Battery assembly: In an argon glove box, the first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector were stacked in the mold in the above order. First, pre-pressing was performed at room temperature and a pressure of 3 MPa for 5 min. Then, the temperature was increased to 80 ℃ and the pressure was increased to 5 MPa, and then the temperature and pressure were maintained for 10 min to obtain a stacked body. Finally, the stacked body was packaged with an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery. The water and oxygen content of the argon glove box was ≤0.1 ppm. The first current collector was a copper foil, and the second current collector was an aluminum foil. The vacuum degree of the vacuum packaging machine was -0.095 MPa. The thickness of the lithium metal negative electrode was 50 μm.

[0029] Example 5 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to the mass ratio of 85:5:2:3, mixed in an argon glove box for 60 min at a speed of 300 rpm using a planetary mixer, and then transferred to a corundum crucible and placed in a tube furnace and heated to 550 ℃ at a rate of 1 ℃ / min, and then sintered for 9 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block, which was then placed in a agate ball mill jar with ethanol as the dispersion medium and ball milled for 2 h to obtain an electrolyte powder, which was then loaded into a mold with a thickness of 200 μm, and then transferred to a cold isostatic pressing machine and pressed at a pressure of 100 MPa for 90 min to obtain a composite solid electrolyte; the water and oxygen content of the argon glove box is ≤0.1 ppm.

[0030] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and VF5 was added after ultrasonic treatment for 30 min, and the mass ratio of Li2SiO3 powder to VF5 was 6:4, and then a uniform sol was formed after stirring, and the sol was coated on the surface of the NCM622 positive electrode sheet, and then transferred to a vacuum drying oven and heated to 80 ℃, and then dried for 2 h, and then transferred to a programmed temperature furnace and heated to 150 ℃ at a rate of 5 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 80 nm, and then a composite positive electrode was obtained.

[0031] (3) Battery assembly: In an argon glove box, the first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector were stacked in the mold in the order of first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector, and then pre-pressed at a pressure of 3 MPa for 5 min at room temperature, and then heated to 80 ℃ and pressurized to 5 MPa, and then held for 10 min, to obtain a stack, and finally, the stack was packaged with an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery; the water and oxygen content of the argon glove box is ≤0.1 ppm, the first current collector is a copper foil, the second current collector is an aluminum foil, the vacuum degree of the vacuum packaging machine is -0.095 MPa, and the thickness of the lithium metal negative electrode is 50 μm.

[0032] Example 6 (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl were weighed according to a mass ratio of 95:1:8:1, mixed in an argon glove box for 30 min at a rotation speed of 500 rpm using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 5 ℃ / min, and then sintered for 4 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block. The sintered block was placed in an agate ball mill jar, ethanol was used as a dispersion medium, and ball milling was performed for 2 h to obtain electrolyte powder. The electrolyte powder was loaded into a mold, the powder thickness was 200 μm, the mold was transferred to a cold isostatic pressing machine, the pressure was 120 MPa, and the pressing time was 30 min to obtain a composite solid electrolyte. The water and oxygen content of the argon glove box was ≤0.1 ppm.

[0033] (2) Preparation of composite positive electrode: Li2SiO3 powder was dispersed in ethanol, and VF5 was added after ultrasonic treatment for 30 min. The mass ratio of Li2SiO3 powder to VF5 was 6:4. After stirring, a uniform sol was formed. The sol was coated on the surface of an NCM622 positive electrode sheet. Then, it was transferred to a vacuum drying oven and heated to 90 ℃, and dried for 2 h. Subsequently, it was transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 1 ℃ / min, and then annealed for 1 h to form a composite intermediate layer with a thickness of 70 nm, thereby obtaining a composite positive electrode.

[0034] (3) Battery assembly: In an argon glove box, a first current collector, a lithium metal negative electrode, a composite solid electrolyte, a composite positive electrode, and a second current collector were stacked in a mold in the above order. First, pre-pressing was performed at room temperature and a pressure of 3 MPa for 5 min. Then, the temperature was increased to 80 ℃ and the pressure was increased to 5 MPa, and then the temperature and pressure were maintained for 10 min to obtain a stacked body. Finally, a vacuum packaging machine was used to package the stacked body with an aluminum-plastic composite film to obtain a solid-state battery. The water and oxygen content of the argon glove box was ≤0.1 ppm. The first current collector was a copper foil, and the second current collector was an aluminum foil. The vacuum degree of the vacuum packaging machine was -0.095 MPa. The thickness of the lithium metal negative electrode was 50 μm.

[0035] Comparative Example 1 (1) Preparation of composite solid electrolyte: LiCl and YCl3 are weighed according to a mass ratio of 3:1, mixed in an argon glove box for 45 min at a rotation speed of 400 rpm by using a planetary mixer, transferred to a corundum crucible, and then placed in a tube furnace and heated to 550 ℃ at a heating rate of 3 ℃ / min, and kept for sintering for 6 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block, which is placed in a corundum ball mill jar with ethanol as a dispersion medium, and ball milled for 2 h to obtain electrolyte powder, which is loaded into a mold with a powder thickness of 200 μm, and then transferred to a cold isostatic pressing machine for pressing at a pressure of 110 MPa for 60 min to obtain a composite solid electrolyte; the water and oxygen content of the argon glove box is ≤0.1 ppm.

[0036] (2) Preparation of electrode slurry: NCM622, acetylene black and electrolyte powder are mixed in a corundum mortar according to a mass ratio of 7:1:2, and then ground with n-heptane as a dispersion medium until a uniform and fine slurry is formed, which is coated on the surface of an NCM622 positive electrode sheet, and then transferred to a vacuum drying oven and heated to 85 ℃ for 2 h, and then transferred to a program-controlled temperature furnace and heated to 150 ℃ at a heating rate of 3 ℃ / min for 1 h to form a composite intermediate layer with a thickness of 90 nm, thereby obtaining a composite positive electrode.

[0037] (3) Battery assembly: in an argon glove box, a first current collector, a lithium metal negative electrode, a composite solid electrolyte, a composite positive electrode and a second current collector are sequentially stacked in a mold, pre-pressed at a pressure of 3 MPa for 5 min at room temperature, heated to 80 ℃ and pressurized to 5 MPa, and kept for 10 min, to obtain a stack, and finally, the stack is packaged with an aluminum-plastic composite film by using a vacuum packaging machine, to obtain a solid-state battery; the water and oxygen content of the argon glove box is ≤0.1 ppm, the first current collector is a copper foil, the second current collector is an aluminum foil, the vacuum degree of the vacuum packaging machine is -0.095 MPa, and the thickness of the lithium metal negative electrode is 50 μm.

[0038] The performance of the above-mentioned multiple examples and comparative examples is tested, and the test results are shown in Table 1.

[0039]

[0040] Table 1 Through analysis of the above data, the solid-state battery prepared by the preparation method of the present application has a significantly improved ionic conductivity, a toughness that is nearly 3 times higher, a lower interface impedance, and simultaneously realizes high-conductivity and high-toughness of the electrolyte, low-resistance stability of the interface, and excellent cycle performance, and has made significant progress.

[0041] The above merely describes preferred embodiments of the present application, and is not intended to limit the technical scope of the present application in any way. Any minor modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application shall still fall within the technical scope of the present application.

Claims

1. A method of making a high-stability halide solid-state battery, the method comprising: Comprising the following steps: ​ (1) Preparation of composite solid electrolyte: Li3YCl6, AlCl3, ZrF4 and LiCl are weighed according to the mass ratio of (85-95):(1-5):(2-8):(1-3), mixed in an argon glove box using a planetary mixer at a speed of 300-500 rpm for 30-60 min, and then transferred to a corundum crucible and placed in a tube furnace and heated to 550 ℃ at a rate of 1-5 ℃ / min, and then sintered for 4-9 h, and then naturally cooled to room temperature in the furnace, to obtain a sintered block, which is then placed in a agate ball mill jar with ethanol as the dispersion medium and ball milled for 2 h to obtain an electrolyte powder, which is then loaded into a mold with a powder thickness of 200 μm, and then transferred to a cold isostatic pressing machine and pressed at a pressure of 100-120 MPa for 30-90 min to obtain a composite solid electrolyte; (2) Preparation of composite positive electrode: Li2SiO3 powder is dispersed in ethanol, and VF5 is added after ultrasonic treatment for 30 min, and the mass ratio of Li2SiO3 powder to VF5 is 6:4, and after stirring, a uniform sol is formed, which is coated on the surface of an NCM622 positive electrode sheet, and then transferred to a vacuum drying oven and heated to 80-90 ℃, and dried for 2 h, and then transferred to a program-controlled furnace and heated to 150 ℃ at a rate of 1-5 ℃ / min, and annealed for 1 h to form a composite intermediate layer with a thickness of 40-90 nm, to obtain a composite positive electrode; (3) Battery assembly: In an argon glove box, the first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector are stacked in the mold in the order of first current collector, lithium metal negative electrode, composite solid electrolyte, composite positive electrode, and second current collector, and then pre-pressed at a pressure of 3 MPa for 5 min at room temperature, and then heated to 80 ℃ and pressurized to 5 MPa, and then held for 10 min, to obtain a stacked body, and finally, the stacked body is packaged with an aluminum-plastic composite film using a vacuum packaging machine to obtain a solid-state battery.

2. The method of claim 1, wherein the method is characterized by: In step (1), the water and oxygen content of the argon glove box is ≤0.1 ppm.

3. The method of claim 1, wherein the method is characterized by: In step (3), the water and oxygen content of the argon glove box is ≤0.1 ppm.

4. The method of claim 1, wherein the method is characterized by: In step (3), the first current collector is a copper foil and the second current collector is an aluminum foil.

5. The method of claim 1, wherein the method is characterized by: In step (3), the vacuum degree of the vacuum packaging machine is -0.095 MPa.

6. The method of claim 1, wherein: In step (3), the thickness of the lithium metal negative electrode is 50 μm.

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