Application of dual-ion conductors in improving the stability of interfacial layers in lithium-ion energy storage devices

Abstract

The present invention provides a use of a dual ion conductor in improving the stability of the interface layer of a lithium ion energy storage device, wherein the lithium ion energy storage device comprises a positive electrode, an electrolyte and a negative electrode, wherein the dual ion conductor is selected from metal halides, Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl, and Li7P2S8I, and the metal halide is selected from at least one of lithium halide, sodium halide, magnesium halide, and silver halide. The dual-ion conductor provided by the present invention achieves in-situ self-repair of the interface layer through the movement of anions during battery cycling, maintaining good contact between the electrolyte and the negative electrode interface, effectively alleviating mechanical damage caused by the negative electrode volume effect. The self-repaired interface layer also inhibits the growth of dendrites in the metal lithium negative electrode, thereby improving the cycle life of the solid-state battery.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage technology. Specifically, the present invention relates to the use of a dual ion conductor in improving the stability of the mechanical structure of the interface layer between the negative electrode and the electrolyte in a lithium ion energy storage device. Background Art

[0002] Solid-state batteries, as a new energy storage technology, are attracting widespread attention due to their potential to meet the high safety, high specific energy, and long life requirements of chemical power sources. However, solid-state batteries still face several key challenges before achieving large-scale application.

[0003] During the assembly of solid-state batteries, the interior and interlayer interfaces of key materials are solid / solid rigid interfaces, resulting in poor contact between key material layers and interlayer interface gaps. Secondly, during the battery cycle, the volume changes of high-energy-density electrode materials such as metallic lithium, silicon, and tin will cause a large number of pores to form inside the negative electrode and at the interface between the negative electrode and the electrolyte, ultimately leading to mechanical damage to the solid-state battery. The pores at the interface will further induce uneven lithium deposition, accelerate the formation of lithium dendrites, and seriously affect the cycle life of the solid-state battery.

[0004] The traditional approach involves pre-building a buffer layer at the interface between the electrode and the electrolyte, but this does not address the problem of numerous cracks and pores forming within the electrode due to the negative electrode volume effect during cycling. Alternatively, a three-dimensional skeleton structure can be constructed for the negative electrode to accommodate the active material to buffer the volume change of the negative electrode, but this significantly reduces the energy density of the battery. Therefore, methods that allow the battery to self-repair mechanical damage to the interface and within the electrode during cycling are of great significance for the practical application of solid-state batteries.

[0005] CN 109728342 B discloses a polymer-based solid-state battery self-repair method that uses an inorganic solid electrolyte and a self-repairing polymer to achieve the polymer's self-repair function for solid-state batteries. This patent addresses the issue of solid-solid contact between key materials during solid-state battery assembly. However, this method requires the addition of more than 50% polymer. This large amount of polymer addition affects the electrolyte's ionic conductivity and is unable to effectively repair pores and cracks within the electrode during battery cycling.

[0006] CN 112687971 A discloses a self-repairing functional interface layer for solid-state batteries. This layer uses a self-repairing polymer, an inorganic solid electrolyte, a lithium salt, and an ether composite. The polymer utilizes intermolecular and intramolecular hydrogen bonds to achieve self-repair of the electrolyte. However, this method cannot effectively repair pores and cracks within the electrode during battery cycling.

[0007] Therefore, there is an urgent need to develop an electrochemically driven self-repair technology to continuously repair the pores and cracks formed in the battery interface layer or inside the electrode during the cycle of solid-state batteries. Summary of the Invention

[0008] The present invention aims to provide a dual-ion conductor for improving the mechanical stability of the interface layer between the negative electrode and the electrolyte in lithium-ion energy storage devices. This method can achieve in-situ self-repair of the interface layer through the migration of anions during battery cycling, maintaining good contact between the electrolyte and the negative electrode, thereby improving the cycle life of solid-state batteries.

[0009] The above-mentioned object of the present invention is achieved through the following technical solutions.

[0010] The present invention provides a use of a dual ion conductor in improving the stability of the mechanical structure of the interface layer between the negative electrode and the electrolyte in a lithium ion energy storage device, wherein the lithium ion energy storage device comprises a positive electrode, an electrolyte and a negative electrode, wherein the dual ion conductor is selected from metal halides, Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I, and the metal halide is selected from at least one of lithium halide, sodium halide, magnesium halide and silver halide.

[0011] The inventors of this application unexpectedly discovered that by adding the dual-ion conductor of the present invention to an energy storage device, the mechanical stability of the interface layer between the negative electrode and the electrolyte in a lithium-ion energy storage device can be improved. Without wishing to be bound by theory, this may be attributed to the fact that the anions of the dual-ion conductor migrate in opposite directions to the cations during battery cycling and become anchored at the interface layer between the negative electrode and the electrolyte, repairing mechanical damage such as cracks and pores caused by volume effects between the metallic lithium negative electrode and the alloy negative electrode, such as silicon or tin.

[0012] Preferably, in the use described in the present invention, the metal halide is lithium halide and / or sodium halide.

[0013] Preferably, in the use described in the present invention, the metal halide is at least one selected from lithium iodide, lithium bromide and sodium bromide.

[0014] Preferably, in the use described in the present invention, the dual ion conductor is selected from Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I, and the dual ion conductor is an electrolyte, or is uniformly dispersed in the positive electrode, the electrolyte or the interface layer between the electrolyte and the negative electrode as an additive.

[0015] Preferably, in the use described in the present invention, the dual ion conductor is selected from at least one of lithium halide, sodium halide, magnesium halide and silver halide, and the dual ion conductor is uniformly dispersed in the positive electrode, electrolyte or the interface layer between the electrolyte and the negative electrode as an additive.

[0016] Preferably, in the use of the present invention, the dual ion conductor is used in combination with another non-ionic conductor, wherein the mass fraction of the non-ionic conductor in the total mass of the dual ion conductor and the non-ionic conductor is less than 50%, preferably less than 20%.

[0017] Preferably, in the use described in the present invention, when the dual ion conductor is uniformly dispersed in the positive electrode, the electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive, the metal halide accounts for 0.1 wt % to 50 wt %, preferably 0.1 wt % to 30 wt % of the interface layer between the positive electrode, the electrolyte, or the electrolyte and the negative electrode.

[0018] Preferably, in the use of the present invention, when the dual ion conductor is uniformly dispersed in the positive electrode, the electrolyte or the interface layer between the electrolyte and the negative electrode as an additive, the dual ion conductor Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I account for 0.1 wt%-50 wt% of the positive electrode and more than 10 wt% of the electrolyte or the interface layer between the electrolyte and the negative electrode.

[0019] Preferably, in the use described in the present invention, the anions of the dual ion conductor move in the opposite direction to the cations during the battery cycle and are anchored in the interface layer between the negative electrode and the electrolyte to repair the mechanical damage of the negative electrode caused by the volume effect.

[0020] In a specific embodiment of the present invention, the dual-ion conductor of the present invention can be applied to solid-state batteries with currently common polymer, oxide, chloride, and sulfide electrolyte systems. During the battery cycle, the in-situ self-repair of the interface layer is achieved through the movement of anions, maintaining good contact between the electrolyte and the negative electrode interface, and effectively alleviating mechanical damage caused by the large volume effect of the high-specific-capacity negative electrode. For the metallic lithium negative electrode, the interface layer formed by self-repair can also inhibit the growth of metallic lithium negative electrode dendrites, thereby improving the cycle life of the solid-state battery.

[0021] In a specific embodiment of the present invention, the dual ion conductor can be used in combination with other commonly used solid electrolytes, for example, by the following method:

[0022] Add 100 mL of acetonitrile to a mixing tank and evenly mix the polymer electrolyte, lithium salt, and dual-ion conductor in a mortar. Weigh 3 g of the mixture into a mixing tank and stir until evenly dispersed. The slurry is evenly coated on a PTFE template and then dried in a 55°C oven for 6 hours. After the temperature cools to room temperature, punch the dried electrolyte membrane into 16 mm diameter discs and quickly transfer them to an argon-filled glove box for storage, resulting in a polymer electrolyte sheet containing the self-healing additive.

[0023] In a specific embodiment of the present invention, the dual ion conductor is thoroughly mixed with a sulfide electrolyte, a chloride electrolyte or an oxide electrolyte by hand milling or ball milling to obtain an inorganic electrolyte with self-healing function.

[0024] In a specific embodiment of the present invention, the dual ion conductor can be uniformly dispersed in the positive electrode. Specifically, the dual ion conductor can be combined with PVDF as a binder, or the dual ion conductor can be combined with a C-containing material as a conductive agent and applied to the positive electrode. Furthermore, for example, this can be done by a method comprising the following steps:

[0025] The dual-ion conductor was added to the PVDF dispersion and stirred thoroughly to completely dissolve. After freeze-drying to completely remove moisture, the mixture was placed in a vacuum oven and kept at 120°C for 6 hours. Once the temperature dropped to room temperature, the composite self-healing additive was quickly transferred to an argon-filled glove box for storage, resulting in a self-healing binder. This binder was then applied to the positive electrode.

[0026] Alternatively, a conductive agent precursor is mixed with a dual-ion conductor, placed in a tube furnace, and calcined at 700°C for 6 hours under argon to obtain a self-healing conductive agent, which is then applied to the positive electrode. Preferably, the conductive agent precursor can be selected from at least one of a conductive polymer monomer, a sugar, asphalt, coke, an alkane gas, and an olefin gas. More preferably, the conductive agent precursor is selected from at least one of aniline monomer, sucrose, glucose, paraffin oil, methane, acetylene, and ethylene.

[0027] Furthermore, in the self-repairing additive of the dual ion conductor and the binder or conductive agent composite of the present invention, the mass fraction of the dual ion conductor is greater than 50%, preferably greater than 80%.

[0028] The present invention has the following beneficial effects:

[0029] The dual-ion conductor provided by the present invention can be applied to solid-state batteries with currently common polymer, oxide, chloride, and sulfide electrolyte systems. During the battery cycle, the movement of anions can achieve in-situ self-repair of the interface layer, maintaining good contact between the electrolyte and the negative electrode interface, and can effectively alleviate the mechanical damage caused by the negative electrode volume effect. At the same time, the interface layer formed by self-repair can also inhibit the growth of metal lithium negative electrode dendrites, thereby improving the cycle life of the solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which:

[0031] Figure 1A The initial impedance spectrum and the impedance spectrum after 50 cycles of the battery numbered a2 according to an embodiment of the present invention are shown;

[0032] Figure 1B The initial impedance spectrum and the impedance spectrum after 50 cycles of the battery number f1 of the control example of the present invention;

[0033] Figure 2 This is a cross-sectional electron micrograph of the interface layer between the negative electrode and the electrolyte of the F1 battery prepared as a control example of the present invention after 50 cycles;

[0034] Figure 3 This is a cross-sectional electron micrograph of the interface layer between the negative electrode and the electrolyte of the A2 battery prepared in accordance with an embodiment of the present invention after 50 cycles. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with specific embodiments. The examples given are only for illustrating the present invention, not for limiting the scope of the present invention.

[0036] Example 1

[0037] In this embodiment, NaI, LiBr, Li6PS5Cl, Li 2.8 PS 3.8 Br 0.2 With Li7P2S8I and AgI as dual ion conductors. These dual ion conductors are evenly dispersed into Li7P3S 11 or PEO solid electrolyte, and Li4Ti5O 12 Solid-state batteries are assembled using silicon as the positive electrode active material and metallic Li as the negative electrode.

[0038] 1. Li7P3S 11 Mix Li4Ti5O with NaI in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive.12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a1.

[0039] 2. Li7P3S 11 Mix LiBr with Li4Ti5O in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a 10 mm diameter PTFE sleeve, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a2.

[0040] 3. Li7P3S 11 Mix Li6PS5Cl in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a3.

[0041] 4. Li7P3S 11 Mix Li4Ti5O with LiF in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11, Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a4.

[0042] 5. Li7P3S 11 With Li 2.8 PS 3.8 Br 0.2 Mix Li7P2S8I with Li4Ti5O in a mortar at a mass ratio of 19:0.5:0.5, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and keep it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a5.

[0043] 6. Add 100mL of acetonitrile to a mixing tank, mix PEO, LiTFSI, and NaI in a mortar at a mass ratio of 30:10:1, weigh 3g and place it in the mixing tank. Stir until evenly dispersed, then evenly coat the slurry on a PTFE template and dry it in a 55°C oven for 6 hours. After the temperature drops to room temperature, punch the dried electrolyte membrane into 16mm diameter discs and quickly transfer them to an argon-filled glove box for storage. Li4Ti5O 12 The electrode is used as the positive electrode and metal Li is used as the negative electrode. The resulting battery is denoted as a6.

[0044] 7. Li7P3S 11 Mix LiBr with Li4Ti5O in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a 10 mm diameter PTFE sleeve, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and the Si electrode was placed on the other side of the electrolyte sheet as the negative electrode, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a7.

[0045] 8. Li7P3S 11 Mix it with AgI in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and keep it under a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing self-healing additives. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as a8.

[0046] Table 1

[0047]

[0048] Example 2

[0049] In this embodiment, LiBr is used as a dual ion conductor, and is uniformly mixed or microstructured with non-ionic conductors such as PVDF and carbon as a self-repairing additive, and is evenly dispersed in the Li4Ti5O 12 In the positive electrode, Li7P3S 11 As a solid electrolyte, metallic Li is used as the negative electrode to assemble the solid-state battery.

[0050] 1. Weigh 5g of 40% PVDF dispersion into a beaker, add 3g of LiBr to the dispersion, stir thoroughly to dissolve the LiBr completely, freeze-dry to completely remove moisture, transfer to a vacuum oven at 120°C for 6 hours, and after the temperature drops to room temperature, quickly transfer the composite self-healing additive to an argon-filled glove box for storage. Weigh Li7P3S 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P, and composite self-healing additive LiBr-PVDF were mixed evenly in a mortar at a mass ratio of 4.5:4:1:0.5 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. A metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as c1.

[0051] 2. Weigh 2.5g of 40% PVDF dispersion into a beaker, add 4g of LiBr to the dispersion, stir thoroughly to dissolve the LiBr completely, freeze-dry to completely remove moisture, transfer to a vacuum oven at 120°C for 6h, and after the temperature drops to room temperature, quickly transfer the composite self-healing additive to an argon-filled glove box for storage. Weigh Li7P3S 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P, and composite self-healing additive LiBr-PVDF were mixed evenly in a mortar at a mass ratio of 4.5:4:1:0.5 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. The metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as c2.

[0052] 3. Add 5g C6H 12 After mixing O6 and 3g LiBr, the mixture was placed in a tube furnace and fired at 700℃ with argon for 6h to obtain the carbon-coated self-healing additive LiBr@C. 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 The composite self-healing additive LiBr@C was mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. The metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as c3.

[0053] 4. Add 2.5g C6H 12 After mixing O6 and 4g LiBr, the mixture was placed in a tube furnace and fired at 700℃ with argon for 6h to obtain the carbon-coated self-healing additive LiBr@C. 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11The composite self-healing additive LiBr@C was mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. The metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as c4.

[0054] Table 2

[0055]

[0056] Example 3

[0057] In this embodiment, Li7P2S8Br is used as a self-repairing additive, and it is used as an electrolyte or a negative electrode interface layer, or is evenly dispersed into Li4Ti5O 12 Positive electrode, Li7P3S 11 , PEO, and LLZTO solid electrolytes, with metallic Li as the negative electrode, to assemble solid-state batteries.

[0058] 1. Weigh 150 mg of Li7P2S8Br and place it in a 10 mm diameter PTFE sleeve. Keep it at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as d1.

[0059] 2. Weigh 150mg Li7P3S 11 The solid electrolyte was placed in a PTFE sleeve with a diameter of 10 mm and maintained at a pressure of 360 MPa for 10 min. Then 20 mg of Li7P2S8Br was weighed and added to the electrolyte sheet and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet with a Li7P2S8Br interface layer to form a Li7P2S8Br interface layer / Li7P3S 11 Electrolyte sheet composite structure. Li4Ti5O 12 、Li7P3S 11 , Super-P in a mortar at a mass ratio of 5:4:1 and mixed evenly as a composite positive electrode. 5 mg was weighed and placed in the above electrolyte sheet Li7P3S 11The opposite side of the Li7P2S8Br interface layer was maintained at 360 MPa for 10 min to form a Li7P2S8Br interface layer / Li7P3S 11 Electrolyte sheet / composite cathode composite structure. A 100μm-thick lithium foil was cut into a 9mm-diameter disc and placed on one side of the Li7P2S8Br interface layer. The cell was maintained at a pressure of 120MPa for 5 minutes. The resulting cell was designated d2.

[0060] 3. Weigh Li7P3S 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P, and self-healing additive Li7P2S8Br were mixed evenly in a mortar at a mass ratio of 4.5:4:1:0.5 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. The metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as d3.

[0061] 4. Li7P3S 11 Mix Li7P2S8Br in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a 10 mm diameter PTFE sleeve, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as d4.

[0062] 5. Add 100mL of acetonitrile to a mixing tank, mix PEO, LiTFSI, and Li7P2S8Br in a mortar at a mass ratio of 30:10:3, weigh 3g and place it in the mixing tank, stir until evenly dispersed, and evenly coat the slurry on a PTFE template. Place it in a 55℃ oven and dry it for 6 hours. After the temperature drops to room temperature, punch the dried electrolyte membrane into a 16mm diameter disc and quickly transfer it to an argon-filled glove box for storage. Li4Ti5O 12 The electrode is used as the positive electrode and metallic Li is used as the negative electrode. The resulting battery is designated as d5.

[0063] 6. LLZTO and Li7P2S8Br were uniformly mixed in a mortar at a mass ratio of 19:1, 150 mg was weighed and placed in a 10 mm diameter PTFE sleeve, maintained at a pressure of 360 MPa for 10 minutes, and sintered at a high temperature of 1150 ° C for 1 hour to obtain an electrolyte sheet containing a self-healing additive. 12 , LLZTO, and Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. A metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as d6.

[0064] Table 3

[0065]

[0066] Example 4

[0067] In this embodiment, LiBr is used as a dual ion conductor and is uniformly dispersed into Li7P3S by grinding, ball milling, and liquid phase compounding. 11 , LLZTO solid electrolyte, Li4Ti5O 12 As the positive electrode active material, metallic Li is used as the negative electrode to assemble a solid-state battery.

[0068] 1. Li7P3S 11 Mix LiBr with Li4Ti5O in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a 10 mm diameter PTFE sleeve, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as e1.

[0069] 2. Li7P3S 11 The electrolyte sheet containing the self-healing additive was obtained by ball milling Li4Ti5O with LiBr at a mass ratio of 19:1 at 400 rpm for 36 hours, and 150 mg was weighed and placed in a 10 mm diameter PTFE sleeve, and maintained at a pressure of 360 MPa for 10 minutes. 12 、Li7P3S 11, Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as e2.

[0070] 3. Add 3.8g LLZTO and 0.2g LiBr to 10ml ethanol, stir thoroughly and ultrasonically to dissolve the LiBr completely and disperse the LLZTO evenly. After drying at 120℃ in vacuum for 6h, weigh 150mg and place it in a 10mm diameter PTFE sleeve. Keep it at 360MPa pressure for 10min and sinter it at 1150℃ for 1h to obtain an electrolyte sheet containing self-healing additives. 12 , LLZTO, and Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. A metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as e3.

[0071] Table 4

[0072]

[0073] Comparative Example 1

[0074] In this comparative example, Li3N, Li3PS4, and LiBr are used as dual ion conductors, which are uniformly mixed with PVDF as self-repairing additives and uniformly dispersed into Li7P3S 11 Solid electrolyte, or Li7P3S 11 , PEO, LLZTO as electrolyte without self-repairing additives, Li4Ti5O 12 As the positive electrode active material, metallic Li is used as the negative electrode to assemble a solid-state battery.

[0075] 1. Li7P3S 11 Weigh 150 mg and place it in a 10 mm diameter PTFE sleeve and keep it at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11, Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f1.

[0076] 2. Add 100mL of acetonitrile to a mixing tank, mix PEO and LiTFSI in a mortar at a mass ratio of 3:1, weigh 3g and place it in the mixing tank, stir until evenly dispersed, and evenly coat the slurry on a PTFE template. Place it in a 55℃ oven and dry it for 6 hours. After the temperature drops to room temperature, punch the dried electrolyte membrane into a 16mm diameter disc and quickly transfer it to an argon-filled glove box for storage. Li4Ti5O 12 The electrode is used as the positive electrode and the metal Li is used as the negative electrode. The resulting battery is recorded as f2.

[0077] 3. Weigh 150 mg of LLZTO and place it in a 10 mm diameter PTFE sleeve, maintain it under a pressure of 360 MPa for 10 min, and sinter it at 1150 ° C for 1 h to obtain an electrolyte sheet. 12 , LLZTO, and Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. A metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f3.

[0078] 4. Li7P3S 11 Mix Li3N with Li4Ti5O in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f4.

[0079] 5. Weigh 10g of 40% PVDF dispersion into a beaker, add 1g of LiBr to the dispersion, stir thoroughly to dissolve the LiBr completely, freeze-dry to completely remove moisture, transfer to a vacuum oven at 120°C for 6h, and after the temperature drops to room temperature, quickly transfer the composite self-healing additive to an argon-filled glove box for storage. Weigh Li7P3S 11 150 mg of solid electrolyte was placed in a 10 mm diameter PTFE sleeve and maintained at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P, and composite self-healing additive LiBr-PVDF were mixed evenly in a mortar at a mass ratio of 4.5:4:1:0.5 as a composite positive electrode. 5 mg was weighed and placed on one side of the electrolyte sheet and maintained at a pressure of 360 MPa for 10 minutes. The metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f5.

[0080] 6. Li7P3S 11 Weigh 150 mg and place it in a 10 mm diameter PTFE sleeve and keep it at a pressure of 360 MPa for 10 min to obtain an electrolyte sheet. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, a metal lithium foil with a thickness of 100 μm was cut into discs with a diameter of 9 mm and placed on the other side of the electrolyte sheet, 20 mg LiBr was weighed and added to the metal lithium side, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f6.

[0081] 7. Li7P3S 11 Mix Li3PS4 with Li4Ti5O in a mortar at a mass ratio of 19:1, weigh 150 mg and place it in a PTFE sleeve with a diameter of 10 mm, and maintain it at a pressure of 360 MPa for 10 minutes to obtain an electrolyte sheet containing a self-healing additive. 12 、Li7P3S 11 , Super-P were mixed evenly in a mortar at a mass ratio of 5:4:1 as a composite positive electrode, 5 mg was weighed and placed on one side of the electrolyte sheet, and maintained at a pressure of 360 MPa for 10 minutes, and a metal lithium foil with a thickness of 100 μm was cut into a disc with a diameter of 9 mm and placed on the other side of the electrolyte sheet, and maintained at a pressure of 120 MPa for 5 minutes. The resulting battery was recorded as f7.

[0082] Table 5

[0083]

[0084] f1: Using Li7P3S 11 (Commonly used sulfide electrolyte) as the electrolyte, without adding the dual ion conductor component with self-repair function, the impedance increases rapidly and the battery life is short;

[0085] f2: Using PEO (common polymer electrolyte) as the electrolyte without adding the dual ion conductor component with self-healing function, the impedance increases rapidly and the battery life is short;

[0086] f3: Using LLZTO (a commonly used oxide electrolyte) as the electrolyte without adding a dual ion conductor component with self-healing function, the impedance increases rapidly and the battery life is short;

[0087] f4: Adding Li3N to Li7P3S 11 In the electrolyte (commonly used sulfide electrolyte), since Li3N is not a dual-ion conductor component with self-healing function, the impedance increases rapidly and the battery life is short;

[0088] f5: LiBr and PVDF are compounded in a solution at a mass ratio of 1:4 and then added to Li7P3S 11 In the electrolyte (commonly used sulfide electrolyte), excessive PVDF blocks the migration path of Br ions, failing to achieve the self-repair function of the dual-ion conductor, resulting in a rapid increase in impedance and a short battery life.

[0089] f6: LiBr was added to the current collector side of the metallic lithium negative electrode, but the self-repair function of the dual-ion conductor could not be realized, the impedance increased rapidly, and the battery life was short.

[0090] f7: Add Li3PS4 to Li7P3S 11 In the (commonly used sulfide electrolyte) electrolyte, since Li3PS4 is not a dual-ion conductor component with self-healing function, the impedance increases rapidly and the battery life is short.

Claims

1. Use of a dual ion conductor in improving the stability of the mechanical structure of the interface layer between the negative electrode and the electrolyte in a lithium ion energy storage device, wherein the lithium ion energy storage device comprises a positive electrode, an electrolyte and a negative electrode, wherein: The dual ion conductor is selected from metal halides, Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I, and the metal halide is selected from at least one of lithium halide, sodium halide, magnesium halide and silver halide; The anions of the dual ion conductor move in opposite directions to the cations during battery cycling and are anchored at the interface between the negative electrode and the electrolyte to repair the mechanical damage to the negative electrode caused by the volume effect. The negative electrode is lithium, silicon or tin; The electrolyte is an oxide, chloride or sulfide electrolyte; The dual ion conductor is selected from Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I and the dual ion conductor is an electrolyte, or is uniformly dispersed in the positive electrode, the electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive; or, the dual ion conductor is selected from at least one of lithium halide, sodium halide, magnesium halide and silver halide and the dual ion conductor is uniformly dispersed in the positive electrode, the electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive; When the dual ion conductor is uniformly dispersed into the electrolyte as an additive, the uniform dispersion is carried out by the following steps: the dual ion conductor is fully mixed with a sulfide electrolyte, a chloride electrolyte or an oxide electrolyte by hand grinding, ball milling or liquid phase compounding to obtain an inorganic electrolyte with self-healing function.

2. The use according to claim 1, wherein The metal halide is lithium halide and / or sodium halide.

3. The use according to claim 1, wherein The metal halide is selected from at least one of lithium iodide, lithium bromide and sodium bromide.

4. The use according to claim 1, wherein The dual ion conductors are used in combination with additional non-ionic conductors.

5. The use according to claim 1, wherein When the dual ion conductor is uniformly dispersed in the positive electrode, electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive, the metal halide accounts for 0.1 wt % to 50 wt % of the positive electrode, electrolyte, or the interface layer between the electrolyte and the negative electrode.

6. The use according to claim 5, wherein When the dual ion conductor is uniformly dispersed in the positive electrode, electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive, the metal halide accounts for 0.1 wt % to 30 wt % of the positive electrode, electrolyte, or the interface layer between the electrolyte and the negative electrode.

7. The use according to claim 1, wherein When the dual ion conductor is uniformly dispersed into the positive electrode, electrolyte, or the interface layer between the electrolyte and the negative electrode as an additive, the dual ion conductor Na 2.8 PS 3.8 Br 0.2 , Li6PS5Cl and Li7P2S8I account for 0.1 wt%-50 wt% of the positive electrode and more than 10 wt% of the electrolyte or the interface layer between the electrolyte and the negative electrode.

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