Battery cell and preparation method therefor, battery device and electric device

Abstract

Provided are a battery cell and a preparation method therefor, a battery device and an electric device. The battery cell comprises an electrode assembly, which comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet. The battery cell further comprises an interface modification layer, which is located between the separator and the negative electrode sheet. The interface modification layer comprises inorganic particles and a polymer, wherein the polymer is located on the surfaces of the inorganic particles and links same together; the inorganic particles have an electronic conductivity of less than 1 S / m at 25°C; and the polymer comprises one or more of polyurethane, polyurea, polyacrylate and polyamide. The battery cell has good cycling stability.

Description

Battery cells and their preparation methods, battery devices and electrical devices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411729882.5, filed on November 28, 2024, entitled “Battery cell and method of preparation thereof, battery device and power consumption device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a battery cell and its preparation method, a battery device, and an electrical device. Background Technology

[0004] Battery cells using lithium metal as the negative electrode material have a much higher energy density than lithium-ion battery cells, which is crucial for applications such as long-range electric vehicles, drones, and electric aircraft. However, the poor cycle capacity of these battery cells has hindered their commercialization. Summary of the Invention

[0005] This disclosure provides a battery cell and its preparation method, a battery device, and an electrical device, wherein the battery cell has good cycle stability.

[0006] In a first aspect, this disclosure provides a battery cell comprising an electrode assembly, the electrode assembly including a positive electrode, a negative electrode, and a separator, the separator being located between the positive electrode and the negative electrode. The battery cell further includes an interface modification layer located between the separator and the negative electrode, the interface modification layer comprising inorganic particles and a polymer, the polymer being located on the surface of the inorganic particles and connecting the inorganic particles, the inorganic particles having an electronic conductivity of less than 1 S / m at 25°C, and the polymer comprising one or more of polyurethane, polyurea, polyacrylate, and polyamide.

[0007] This disclosure discloses an interface modification layer between the separator and the negative electrode sheet. The interface modification layer includes inorganic particles. These inorganic particles exhibit good stability, can remain stably within the battery cell for a long period, and exhibit almost no side reactions with the electrolyte and lithium metal. This allows their morphology and chemical composition to remain stable during the charge-discharge process of the battery cell. Therefore, the inorganic particles act as uniform ion channels and uniform lithium ion distribution on the negative electrode side during the cyclic charge-discharge process of the battery cell, thereby uniformly morphologically depositing lithium metal on the negative electrode, reducing dendrite formation, and minimizing negative electrode volume expansion. Furthermore, the electronic conductivity of the inorganic particles at 25°C is less than 1 S / m, significantly lower than that of lithium metal, which further reduces the problem of lithium ion deposition on the surface of the inorganic particles. The interface modification layer includes a polymer, which is located on the surface of the inorganic particles and connects them. The polymer includes one or more of polyurethane, polyurea, polyacrylate, and polyamide. These polymers can improve the wettability of the electrolyte at the negative electrode interface and bind the electrolyte during the cyclic charge-discharge process of the battery cell.

[0008] In the later stages of battery cell cycling and after the rSEI layer is formed, some inorganic particles near the rSEI layer mix with broken rSEI layer, dead lithium and other substances, causing the interface modification layer to form a framework-like structure near the negative electrode. This can form a channel for electrolyte transport and promote the rapid deposition and stripping of lithium ions through the rSEI layer.

[0009] Therefore, the battery cell of this application can have good cycle stability.

[0010] In some embodiments, the polymer includes one or more of polyurethane and polyurea. Polyurethane and polyurea have structures similar to the solvents in the electrolyte, and polyurea and polyurethane can also interact with the polar functional groups in the electrolyte, thereby effectively binding the electrolyte; in addition, polyurea and polyurethane also have good encapsulation and adhesion properties.

[0011] In some embodiments, the polymer has a cross-linked structure. The cross-linked structure of the polymer prevents it from dissolving in the electrolyte and reduces its swelling in the electrolyte. This reduces the problems of a sharp increase in electrolyte viscosity and a sudden deterioration in electrolyte wettability at the negative electrode interface during long-term use of the battery cell, thereby enabling the battery cell to have long-term cycle stability.

[0012] In some embodiments, the polyurethane has -NHCOO- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional groups to the -NHCOO- functional groups is 0.01:1 to 0.5:1, optionally 0.02:1 to 0.1:1. The polyurethane has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0013] In some embodiments, the polyurethane has polyether segments. These polyether segments can give the polyurethane good flexibility, encapsulation, and adhesion.

[0014] In some embodiments, the polyurea has -NHCONH- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional groups to the -NHCONH- functional groups is from 0.01:1 to 0.5:1, optionally from 0.02:1 to 0.1:1. The polyurea has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0015] In some embodiments, the polyurea has polyether segments. These polyether segments can give the polyurea good flexibility, coating properties, and adhesiveness.

[0016] In some embodiments, the mass ratio of the polymer to the inorganic particles is 1:4 to 1:19, optionally 1:7 to 1:13. A mass ratio of polymer to inorganic particles within this range allows the interface modification layer to better achieve the functions of uniform negative electrode lithium metal deposition morphology, improved electrolyte wettability at the negative electrode interface, and electrolyte binding, thereby enhancing the cycle performance of the battery cell.

[0017] In some embodiments, the thickness of the interface modification layer is 0.8 μm-20 μm, optionally 2 μm-6 μm. This results in a higher number of inorganic particle stacks, which better facilitates the uniform distribution of lithium ions on the negative electrode side during battery cell cycling, leading to a more uniform lithium metal deposition morphology, reduced dendrite formation, and decreased negative electrode volume expansion. Furthermore, it allows the interface modification layer to form a framework-like structure near the negative electrode sheet in the later stages of battery cell cycling, promoting rapid lithium ion deposition and stripping through the rSEI layer.

[0018] In some embodiments, the volumetric particle size Dv50 of the inorganic particles is 0.02 μm-0.5 μm, optionally 0.1 μm-0.3 μm. The smaller particle size of the inorganic particles results in a greater number of stacked layers for the same coating thickness. This allows for better uniformity of ion channels and lithium-ion distribution on the negative electrode side during the cycle charging and discharging of the battery cell. Consequently, it leads to a more uniform lithium metal deposition morphology on the negative electrode, reducing dendrite formation and decreasing negative electrode volume expansion. Furthermore, it facilitates the formation of a framework-like structure near the negative electrode sheet in the later stages of battery cell cycling, promoting rapid lithium-ion deposition and stripping through the rSEI layer.

[0019] In some embodiments, the thickness of the interface modification layer is more than 6 times the volume distribution particle size Dv50 of the inorganic particles. This results in a higher number of inorganic particle stacks, which better facilitates the uniform distribution of lithium ions on the negative electrode side during the cycle charging and discharging of the battery cell. This leads to a more uniform lithium metal deposition morphology on the negative electrode, reducing dendrite formation and negative electrode volume expansion. Furthermore, it allows the interface modification layer to form a framework-like structure near the negative electrode sheet in the later stages of battery cell cycling, promoting rapid lithium ion deposition and stripping through the rSEI layer.

[0020] In some embodiments, the inorganic particles include one or more of ceramics and inorganic solid electrolyte materials.

[0021] In some embodiments, the inorganic particles include one or more of a solid structure, a porous structure, and a hollow structure.

[0022] In some embodiments, the inorganic particles have hydroxyl groups on their surface. These hydroxyl groups can anchor electrolyte anions, increasing the lithium-ion transference number.

[0023] In some embodiments, the negative electrode sheet includes a negative current collector, which is a metal foil or a composite current collector. The composite current collector includes a polymer material base layer and a metal material layer formed on at least one side of the polymer material base layer.

[0024] In some embodiments, the negative electrode sheet further includes a lithiophilic layer located on at least one side of the negative electrode current collector, and the interface modification layer is located between the separator and the lithiophilic layer.

[0025] In some embodiments, the negative electrode sheet includes a negative current collector and a lithium-based metal layer located on at least one side of the negative current collector, the interface modification layer is located between the separator and the lithium-based metal layer, the negative current collector is a metal foil or a composite current collector, and the composite current collector includes a polymer material base layer and a metal material layer formed on at least one side of the polymer material base layer.

[0026] In some embodiments, the separating membrane comprises a porous base membrane.

[0027] In some embodiments, the separator includes a porous base membrane and a heat-resistant coating located on at least one side of the porous base membrane, the interface modification layer is located between the heat-resistant coating and the negative electrode sheet, and the heat-resistant coating includes one or more of organic particles, inorganic particles, and organic-inorganic composite particles.

[0028] Secondly, this disclosure provides a method for preparing a battery cell, comprising the following steps: providing a positive electrode, a negative electrode, a separator, and an electrolyte; providing a slurry comprising a polymer, inorganic particles, and a solvent, wherein the inorganic particles have an electronic conductivity of less than 1 S / m at 25°C, and the polymer comprises one or more of polyurethane, polyurea, polyacrylate, and polyamide; coating the slurry onto the surface of the negative electrode and / or the separator, and drying it to form a negative electrode and / or the separator with an interface modification layer, wherein the interface modification layer comprises inorganic particles and a polymer, the polymer being located on the surface of the inorganic particles and connecting the inorganic particles; assembling the positive electrode, the negative electrode, the separator, and the electrolyte to obtain a battery cell, wherein the separator is located between the positive electrode and the negative electrode, and the negative electrode and / or the separator has the interface modification layer, and the interface modification layer is located between the separator and the negative electrode.

[0029] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent includes the following steps: reacting a first polyether polyol and a first polyisocyanate at a first temperature for a first time to obtain an NCO-terminated polyurethane prepolymer, and then adding a second polyether polyol and inorganic particles to obtain the slurry.

[0030] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent includes the following steps: reacting a third polyether polyol and a second polyisocyanate at a second temperature for a second time to obtain an OH-terminated polyurethane prepolymer, and then adding the third polyisocyanate and inorganic particles to obtain the slurry.

[0031] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles and a solvent includes the following steps: reacting a first polyether polyamine and a fourth polyisocyanate at a third temperature for a third time to obtain an NCO-terminated polyurea prepolymer, and then adding a second polyether polyamine and inorganic particles to obtain the slurry.

[0032] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent includes the following steps: reacting a third polyether polyamine and a fifth polyisocyanate at a fourth temperature for a fourth time to obtain an NH2-terminated polyurea prepolymer, and then adding a sixth polyisocyanate and inorganic particles to obtain the slurry.

[0033] In some embodiments, the molar ratio of the -OH functional group of the first polyether polyol to the molar ratio of the -NCO functional group of the first polyisocyanate is 1:1.01 to 1:1.3.

[0034] In some embodiments, the ratio of the molar amount of the -OH functional groups of the first polyether polyol and the sum of the molar amounts of the -OH functional groups of the second polyether polyol to the molar amount of the -NCO functional groups of the first polyisocyanate is from 1:1.01 to 1:1.5, optionally from 1:1.02 to 1:1.1. When the ratio of the molar amount of the -OH functional groups of the first polyether polyol and the sum of the molar amounts of the -OH functional groups of the second polyether polyol to the molar amount of the -NCO functional groups of the first polyisocyanate is within the above range, the prepared polyurethane has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0035] In some embodiments, the first temperature is 25°C-80°C.

[0036] In some embodiments, the first time is 3h-6h.

[0037] In some embodiments, the molar ratio of the -OH functional group of the third polyether polyol to the molar ratio of the -NCO functional group of the second polyisocyanate is 1.01:1 to 1.2:1.

[0038] In some embodiments, the molar ratio of the -OH functional group of the third polyether polyol to the sum of the molar ratios of the -NCO functional groups of the second and third polyisocyanates is 1:1.01 to 1:1.5, optionally 1:1.02 to 1:1.1. When the molar ratio of the -OH functional group of the third polyether polyol to the sum of the molar ratios of the -NCO functional groups of the second and third polyisocyanates is within the above range, the prepared polyurethane has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0039] In some embodiments, the second temperature is 25°C-80°C.

[0040] In some embodiments, the second time is 3h-6h.

[0041] In some embodiments, the molar ratio of the -NH2 functional group of the first polyether polyamine to the molar ratio of the -NCO functional group of the fourth polyisocyanate is 1:1.01 to 1:1.3.

[0042] In some embodiments, the ratio of the molar amount of the -NH2 functional groups of the first polyether polyamine and the sum of the molar amounts of the -NH2 functional groups of the second polyether polyamine to the molar amount of the -NCO functional groups of the fourth polyisocyanate is from 1:1.01 to 1:1.5, optionally from 1:1.02 to 1:1.1. When the ratio of the molar amounts of the -NH2 functional groups of the first polyether polyamine and the sum of the molar amounts of the -NH2 functional groups of the second polyether polyamine to the molar amount of the -NCO functional groups of the fourth polyisocyanate is within the above range, the prepared polyurea has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0043] In some embodiments, the third temperature is 25°C-80°C.

[0044] In some embodiments, the third time is 3h-6h.

[0045] In some embodiments, the molar ratio of the -NH2 functional group of the third polyether polyamine to the molar ratio of the -NCO functional group of the fifth polyisocyanate is 1.01:1 to 1.2:1.

[0046] In some embodiments, the molar ratio of the -NH2 functional group of the third polyether polyamine to the sum of the molar ratios of the -NCO functional groups of the fifth polyisocyanate and the sixth polyisocyanate is 1:1.01 to 1:1.5, optionally 1:1.02 to 1:1.1. When the molar ratio of the -NH2 functional group of the third polyether polyamine to the sum of the molar ratios of the -NCO functional groups of the fifth and sixth polyisocyanates is within the above range, the prepared polyurea has an appropriate amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0047] In some embodiments, the fourth temperature is 25°C-80°C.

[0048] In some embodiments, the fourth time is 3h-6h.

[0049] In some embodiments, the viscosity of the first polyether polyol at 25°C is 10 mPa·s-100000 mPa·s.

[0050] In some embodiments, the weight-average molecular weight of the first polyether polyol is 400-5000.

[0051] In some embodiments, the first polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0052] In some embodiments, the functionality of the first polyether polyol is 2 to 4.

[0053] In some embodiments, the viscosity of the second polyether polyol at 25°C is 10 mPa·s-100000 mPa·s.

[0054] In some embodiments, the weight-average molecular weight of the second polyether polyol is 400-5000.

[0055] In some embodiments, the second polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0056] In some embodiments, the functionality of the second polyether polyol is 2 to 4.

[0057] In some embodiments, the viscosity of the third polyether polyol at 25°C is 10 mPa·s-100000 mPa·s.

[0058] In some embodiments, the weight-average molecular weight of the third polyether polyol is 400-5000.

[0059] In some embodiments, the third polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0060] In some embodiments, the functionality of the third polyether polyol is 2 to 4.

[0061] In some embodiments, the viscosity of the first polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s.

[0062] In some embodiments, the weight-average molecular weight of the first polyether polyamine is 200-8000.

[0063] In some embodiments, the viscosity of the second polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s.

[0064] In some embodiments, the weight-average molecular weight of the second polyether polyamine is 200-8000.

[0065] In some embodiments, the viscosity of the third polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s.

[0066] In some embodiments, the weight-average molecular weight of the third polyether polyamine is 200-8000.

[0067] In some embodiments, the functionality of the first polyether polyamine is 2 to 4.

[0068] In some embodiments, the functionality of the second polyether polyamine is 2 to 4.

[0069] In some embodiments, the functionality of the third polyether polyamine is 2 to 4.

[0070] In some embodiments, the viscosity of the first polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0071] In some embodiments, the functionality of the first polyisocyanate is 2 to 4.

[0072] In some embodiments, the viscosity of the second polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0073] In some embodiments, the functionality of the second polyisocyanate is 2 to 4.

[0074] In some embodiments, the viscosity of the third polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0075] In some embodiments, the functionality of the third polyisocyanate is 2 to 4.

[0076] In some embodiments, the viscosity of the fourth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0077] In some embodiments, the functionality of the fourth polyisocyanate is 2 to 4.

[0078] In some embodiments, the viscosity of the fifth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0079] In some embodiments, the fifth polyisocyanate has a functionality of 2 to 4.

[0080] In some embodiments, the viscosity of the sixth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

[0081] In some embodiments, the sixth polyisocyanate has a functionality of 2 to 4.

[0082] In some embodiments, the functionality of the second polyether polyol is greater than that of the first polyether polyol.

[0083] In some embodiments, the functionality of the first polyisocyanate is 2, the functionality of the first polyether polyol is 2, and the functionality of the second polyether polyol is 3 to 4. This allows the preparation of a polyurethane with a three-dimensional cross-linked structure. The polyurethane has a cross-linked structure, is insoluble in the electrolyte, and exhibits low swelling in the electrolyte. This reduces the problems of a sharp increase in electrolyte viscosity and a sudden deterioration in electrolyte wettability at the negative electrode interface during long-term use of the battery cell, thereby enabling the battery cell to have long-cycle stability. Furthermore, the prepared polyurethane also possesses good flexibility, encapsulation, and adhesion.

[0084] In some embodiments, the functionality of the third polyisocyanate is greater than that of the second polyisocyanate.

[0085] In some embodiments, the third polyether polyol has a functionality of 2, the second polyisocyanate has a functionality of 2, and the third polyisocyanate has a functionality of 3 to 4. This allows for the preparation of a polyurethane with a three-dimensional cross-linked structure. The polyurethane has a cross-linked structure, is insoluble in the electrolyte, and exhibits low swelling in the electrolyte. This reduces the problems of a sharp increase in electrolyte viscosity and a sudden deterioration in electrolyte wettability at the negative electrode interface during long-term use of the battery cell, thereby enabling the battery cell to have long-cycle stability. Furthermore, the prepared polyurethane also possesses good flexibility, encapsulation, and adhesion.

[0086] In some embodiments, the functionality of the second polyether polyamine is greater than that of the first polyether polyamine.

[0087] In some embodiments, the fourth polyisocyanate has a functionality of 2, the first polyether polyamine has a functionality of 2, and the second polyether polyamine has a functionality of 3 to 4. This allows for the preparation of a polyurea with a three-dimensional cross-linked structure. The polyurea has a cross-linked structure, is insoluble in the electrolyte, and exhibits low swelling in the electrolyte. This reduces the problems of a sharp increase in electrolyte viscosity and a sudden deterioration in electrolyte wettability at the negative electrode interface during long-term use of the battery cell, thereby enabling the battery cell to have long-cycle stability. Furthermore, the prepared polyurea also possesses good flexibility, coating properties, and adhesion.

[0088] In some embodiments, the sixth polyisocyanate has a greater functionality than the fifth polyisocyanate.

[0089] In some embodiments, the third polyether polyamine has a functionality of 2, the fifth polyisocyanate has a functionality of 2, and the sixth polyisocyanate has a functionality of 3 to 4. This allows for the preparation of a polyurea with a three-dimensional cross-linked structure. The polyurea has a cross-linked structure, is insoluble in electrolyte, and exhibits low swelling in electrolyte. This reduces the problems of rapid increase in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of the battery cell, thereby enabling the battery cell to have long-cycle stability. Furthermore, the prepared polyurea also possesses good flexibility, coating properties, and adhesion.

[0090] In some embodiments, the first polyether polyol includes one or more of N210, N220, N230, N240, N260, and 204.

[0091] In some embodiments, the second polyether polyol includes one or more of N330, N310, N3050, N3500, 330N, and 403.

[0092] In some embodiments, the third polyether polyol includes one or more of N210, N220, N230, N240, N260, 204, N330, N310, N3050, N3500, 330N, and 403.

[0093] In some embodiments, the first polyether polyamine includes one or more of D2000, D400, and D230.

[0094] In some embodiments, the second polyether polyamine includes one or more of D400, T5000, and T403.

[0095] In some embodiments, the third polyether polyamine includes one or more of D2000, D400, D230, T5000, and T403.

[0096] In some embodiments, the first polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0097] In some embodiments, the second polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0098] In some embodiments, the third polyisocyanate includes one or more of hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0099] In some embodiments, the fourth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0100] In some embodiments, the fifth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0101] In some embodiments, the sixth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0102] In some embodiments, the solvent of the slurry includes one or more of N-methylpyrrolidone and tetrahydrofuran.

[0103] In some embodiments, the viscosity of the slurry at 25°C is 100 mPa·s-1000 mPa·s.

[0104] In some embodiments, the solid content of the slurry is 10%-60%.

[0105] Thirdly, this disclosure provides a battery device comprising a plurality of battery cells according to the first aspect or a plurality of battery cells prepared by the preparation method of the second aspect.

[0106] Fourthly, this disclosure provides an electrical device comprising a battery cell according to the first aspect, or a battery cell prepared by the preparation method of the second aspect, or a battery device according to the third aspect. Attached Figure Description

[0107] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0108] Figure 1 shows a schematic diagram of a battery cell provided in some embodiments of this disclosure.

[0109] Figure 2 shows a schematic diagram of an electrical device provided in some embodiments of this disclosure.

[0110] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0111] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the battery cell, its preparation method, battery device, and power-consuming device of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0112] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0113] Unless otherwise specified, all embodiments and optional embodiments of this disclosure may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this disclosure.

[0114] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0115] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0116] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0117] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0118] In the description of the embodiments of this disclosure, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0119] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0120] The battery cells mentioned in the embodiments of this disclosure are capable of charging and discharging independently. The battery cells may be cylindrical, cuboid, or other shapes, and this disclosure does not limit this. Figure 1 shows an example of a cuboid battery cell.

[0121] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0122] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0123] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0124] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0125] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0126] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0127] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0128] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0129] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0130] The technical solutions described in this disclosure are applicable to various electrical devices that use battery cells or battery devices, such as, but not limited to, mobile devices (e.g., mobile phones, tablets, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. Battery cells and battery devices are used to store or provide electrical energy.

[0131] Figure 2 is a schematic diagram of an example electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0132] The battery cells provided in the embodiments of this disclosure can be lithium metal battery cells, negative electrode-free lithium metal battery cells, etc.

[0133] A negative electrode-free lithium metal battery cell typically refers to a battery cell in which no negative electrode active material layer is actively formed on the negative electrode side during the manufacturing process. For example, during the manufacturing process, a negative electrode active material layer formed of carbonaceous materials is not formed at the negative electrode through coating or deposition processes, and a lithium-based metal layer is not actively formed on the negative electrode side. During the first charge, ions gain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form lithium metal. During discharge, the lithium metal can be converted back into lithium ions and return to the positive electrode, achieving cyclic charging and discharging.

[0134] Lithium metal possesses a high theoretical specific capacity (3860 mAh / g) and a low reduction potential (-3.04 V vs. SHE), making it a highly promising anode material. However, lithium metal anodes operate on a deposition / stripping mechanism during charge and discharge, causing repeated volume expansion and contraction of the battery cell. Furthermore, this often results in poor electrolyte wetting in the central area of ​​the cell. Consequently, battery cells using lithium metal as the anode material typically exhibit poor long-cycle performance.

[0135] Based on this, the present disclosure provides a single battery cell with good cycle stability.

[0136] The battery cell disclosed herein includes an electrode assembly comprising a positive electrode, a negative electrode, and a separator, wherein the separator is located between the positive and negative electrode. The battery cell also includes an interface modification layer located between the separator and the negative electrode. The interface modification layer comprises inorganic particles and a polymer, wherein the polymer is located on the surface of the inorganic particles and connects the inorganic particles, the inorganic particles having an electronic conductivity of less than 1 S / m at 25°C, and the polymer comprising one or more of polyurethane, polyurea, polyacrylate, and polyamide.

[0137] The ion channels on the surface of the separator are usually unevenly distributed, and the surface of the negative electrode is usually rough and uneven. This can easily lead to uneven deposition of lithium metal on the negative electrode, which in turn can cause dendrite growth. In addition, with the volume expansion / contraction of the negative electrode, the solid electrolyte interphase (SEI) film of the negative electrode will repeatedly break and regenerate, forming a rSEI layer. This rSEI layer is relatively dense and has poor wettability to the electrolyte, which is not conducive to the rapid deposition and stripping of lithium ions through the rSEI layer.

[0138] This disclosure discloses an interface modification layer between the separator and the negative electrode sheet. The interface modification layer includes inorganic particles. These inorganic particles exhibit good stability, can remain stably within the battery cell for a long period, and exhibit almost no side reactions with the electrolyte and lithium metal. This allows their morphology and chemical composition to remain stable during the charge-discharge process of the battery cell. Therefore, the inorganic particles act as uniform ion channels and uniform lithium ion distribution on the negative electrode side during the cyclic charge-discharge process of the battery cell, thereby uniformly morphologically depositing lithium metal on the negative electrode, reducing dendrite formation, and minimizing negative electrode volume expansion. Furthermore, the electronic conductivity of the inorganic particles at 25°C is less than 1 S / m, significantly lower than that of lithium metal, which further reduces the problem of lithium ion deposition on the surface of the inorganic particles. The interface modification layer includes a polymer, which is located on the surface of the inorganic particles and connects them. The polymer includes one or more of polyurethane, polyurea, polyacrylate, and polyamide. These polymers can improve the wettability of the electrolyte at the negative electrode interface and bind the electrolyte during the cyclic charge-discharge process of the battery cell.

[0139] In the later stages of battery cell cycling and after the rSEI layer is formed, some inorganic particles near the rSEI layer mix with broken rSEI layer, dead lithium and other substances, causing the interface modification layer to form a framework-like structure near the negative electrode. This can form a channel for electrolyte transport and promote the rapid deposition and stripping of lithium ions through the rSEI layer.

[0140] Therefore, the battery cell of this application can have good cycle stability.

[0141] In some embodiments, the polymer may include one or more of polyurethane and polyurea.

[0142] Polyurethane and polyurea have similar structures to the solvents in the electrolyte. Polyurea and polyurethane can also interact with the polar functional groups in the electrolyte, thereby effectively binding the electrolyte. In addition, polyurea and polyurethane also have good coating and adhesion properties.

[0143] In some embodiments, the polymer has a cross-linked structure.

[0144] The polymer has a cross-linked structure, which makes it insoluble in the electrolyte and has a small degree of swelling in the electrolyte. This can reduce the problems of rapid increase in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of battery cells, thereby enabling battery cells to have long-cycle stability.

[0145] In some embodiments, the polyurethane has a cross-linked structure.

[0146] In some embodiments, the polyurea has a cross-linked structure.

[0147] It is understood that polyurethane has a -NHCOO- functional group, which is obtained through the reaction of a -NCO functional group and a -OH functional group. Optionally, polyurethane may also have unreacted -NCO functional groups and / or -OH functional groups.

[0148] In some embodiments, the polyurethane has -NHCOO- functional groups and -NCO functional groups, and the ratio of the molar amount of -NCO functional groups to the molar amount of -NHCOO- functional groups is greater than 0:1 and less than or equal to 0.5:1.

[0149] Polyurethane has a suitable amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further crosslinking.

[0150] Optionally, the molar ratio of the -NCO functional group to the -NHCOO- functional group can be from 0.01:1 to 0.5:1, for example, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.12:1, 0.14:1. 0.16:1, 0.18:1, 0.2:1, 0.22:1, 0.24:1, 0.26:1, 0.28:1, 0.3:1, 0.32:1, 0.34:1, 0.36:1, 0.38:1, 0.4:1, 0.42:1, 0.44:1, 0.46:1, 0.48:1, 0.5:1, or any range of the above values.

[0151] Optionally, the molar ratio of the -NCO functional group to the -NHCOO- functional group can be 0.02:1 to 0.4:1, 0.02:1 to 0.3:1, 0.02:1 to 0.2:1, 0.02:1 to 0.18:1, 0.02:1 to 0.16:1, 0.02:1 to 0.14:1, 0.02:1 to 0.12:1, 0.02:1 to 0.1:1, 0.04:1 to 0.4:1, 0.04:1 to 0.3:1, 0.04:1 to 0.2:1, 0.04:1 to 0.18:1, 0.04:1 to 0.16:1, 0.04:1 to 0.14:1, 0.04:1 to 0.12:1, or 0.04:1 to 0.1:1.

[0152] In some embodiments, the polyurethane has polyether segments. The polyether segments can give the polyurethane good flexibility, encapsulation, and adhesion.

[0153] It is understood that polyurea has a -NHCONH- functional group, which is obtained through the reaction of a -NCO functional group and a -NH2 functional group. Optionally, polyurea may also have unreacted -NCO functional groups and / or -NH2 functional groups.

[0154] In some embodiments, the polyurea has -NHCONH- functional groups and -NCO functional groups, and the ratio of the molar amount of -NCO functional groups to the molar amount of -NHCONH- functional groups is greater than 0:1 and less than or equal to 0.5:1.

[0155] Polyurea has a suitable amount of unreacted -NCO functional groups, which can react with trace amounts of water in the environment and undergo further cross-linking.

[0156] Optionally, the molar ratio of the -NCO functional group to the -NHCONH- functional group can be from 0.01:1 to 0.5:1, for example, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.12:1, 0.14: 1. 0.16:1, 0.18:1, 0.2:1, 0.22:1, 0.24:1, 0.26:1, 0.28:1, 0.3:1, 0.32:1, 0.34:1, 0.36:1, 0.38:1, 0.4:1, 0.42:1, 0.44:1, 0.46:1, 0.48:1, 0.5:1, or any range of the above values.

[0157] Optionally, the molar ratio of the -NCO functional group to the -NHCONH- functional group can be 0.02:1 to 0.4:1, 0.02:1 to 0.3:1, 0.02:1 to 0.2:1, 0.02:1 to 0.18:1, 0.02:1 to 0.16:1, 0.02:1 to 0.14:1, 0.02:1 to 0.12:1, 0.02:1 to 0.1:1, 0.04:1 to 0.4:1, 0.04:1 to 0.3:1, 0.04:1 to 0.2:1, 0.04:1 to 0.18:1, 0.04:1 to 0.16:1, 0.04:1 to 0.14:1, 0.04:1 to 0.12:1, or 0.04:1 to 0.1:1.

[0158] In some embodiments, the polyurea has polyether segments. The polyether segments can give the polyurea good flexibility, coating properties, and adhesiveness.

[0159] In some embodiments, the mass ratio of polymer to inorganic particles can be from 1:4 to 1:19, for example, it can be 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, or any range of the above values.

[0160] Inorganic particles play a role in uniformly distributing ion channels and lithium ions on the negative electrode side during battery cell cycle charging and discharging, thereby achieving a uniform lithium metal deposition morphology, reducing dendrite formation, and minimizing negative electrode volume expansion. Polymers improve electrolyte wettability and electrolyte binding at the negative electrode interface during cycle charging and discharging. When the polymer-to-inorganic particle mass ratio is within the aforementioned range, the interface modification layer can better achieve the combined effects of uniform lithium metal deposition morphology, improved electrolyte wettability, and electrolyte binding, thus enhancing the cycle performance of the battery cell.

[0161] Optionally, the mass ratio of polymer to inorganic particles can be 1:4 to 1:17, 1:5 to 1:17, 1:6 to 1:17, 1:7 to 1:17, 1:4 to 1:15, 1:5 to 1:15, 1:6 to 1:15, 1:7 to 1:15, 1:4 to 1:13, 1:5 to 1:13, 1:6 to 1:13, or 1:7 to 1:13.

[0162] The mass ratio of polymer to inorganic particles can be determined by thermogravimetric analysis.

[0163] In some embodiments, inorganic particles may include one or more of ceramics and inorganic solid electrolyte materials.

[0164] In some embodiments, inorganic particles may include one or more of the following: spherical, near-spherical, and irregular shapes.

[0165] In some embodiments, inorganic particles may include one or more of the following: solid structure, porous structure, and hollow structure.

[0166] Alternatively, the porous structure can be a mesoporous structure, such as a mesoporous sphere.

[0167] Optionally, the hollow structure may include a solid hollow structure or a porous hollow structure. Optionally, the porous hollow structure may be a mesoporous hollow structure, such as a mesoporous hollow sphere.

[0168] In some embodiments, the volume distribution particle size Dv50 of the inorganic particles can be 0.02μm-0.5μm, for example, it can be 0.02μm, 0.04μm, 0.06μm, 0.08μm, 0.1μm, 0.12μm, 0.14μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.26μm, 0.28μm, 0.3μm, 0.32μm, 0.34μm, 0.36μm, 0.38μm, 0.4μm, 0.42μm, 0.44μm, 0.46μm, 0.48μm, 0.5μm, or any range of the above values.

[0169] Inorganic particles have small particle sizes, and with the same coating thickness, they can accumulate more layers. This allows them to better serve as uniform ion channels and lithium-ion distribution on the negative electrode side during the cycle charging and discharging of a single battery cell. Consequently, they can better uniformize the lithium metal deposition morphology on the negative electrode, reduce dendrite formation, and decrease negative electrode volume expansion. Furthermore, they can better form a framework-like structure near the negative electrode sheet in the later stages of battery cell cycling, promoting rapid lithium-ion deposition and stripping through the rSEI layer.

[0170] Optionally, the volume distribution particle size Dv50 of the inorganic particles can be 0.06μm-0.4μm, 0.08μm-0.4μm, 0.1μm-0.4μm, 0.06μm-0.36μm, 0.08μm-0.36μm, 0.1μm-0.36μm, 0.06μm-0.32μm, 0.08μm-0.32μm, 0.1μm-0.32μm, 0.06μm-0.3μm, 0.08μm-0.3μm, or 0.1μm-0.3μm.

[0171] In some embodiments, the surface of the inorganic particles may have hydroxyl groups. These hydroxyl groups can anchor electrolyte anions, thereby increasing the lithium-ion transference number.

[0172] In some embodiments, the ceramic may include one or more of SiO2, Al2O3, TiO2, ZrO2, SiC, CaO, MgO, AlF3, Li2O, and Na2O.

[0173] Optionally, the ceramic may include one or both of SiO2 and Al2O3.

[0174] SiO2 and Al2O3 can exist stably in both the electrolyte and the negative electrode, and their surfaces are rich in hydroxyl groups, which can anchor anions and increase the lithium-ion transference number.

[0175] Alternatively, Al2O3 can be α-Al2O3.

[0176] In some embodiments, inorganic solid electrolyte materials may include one or more of oxide solid electrolyte materials, halide solid electrolyte materials, and sulfide solid electrolyte materials.

[0177] Optionally, the oxide solid electrolyte material may include one or more of the following: NASICON-type solid electrolyte, LISICON-type solid electrolyte, perovskite-type solid electrolyte, and garnet-type solid electrolyte. As an example, the oxide solid electrolyte material may include, but is not limited to, Li5La3Ti2O. 12 Li7La3Zr2O 12 Li4Ti5O 12 Li 14 Zn(GeO4)4, LiTi2(PO4)3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+y Al y Ge 2-y One or more of (PO4)3, 0 < x < 2, 0 < y < 2.

[0178] Optionally, the halide solid electrolyte material may be one or more of Li3YCl6, Li3YBr6, Li3ErCl6, Li3InCl6, and Li3InBr6, including but not limited to.

[0179] Optionally, the sulfide solid electrolyte material may include one or more of the following: silver-germanium sulfide type, LGPS type, Li₂S-GeS₂ type, Li₂S-P₂S₅ type, Li₂S-SiS₂ type, and Li₂S-MeS-P₂S₅ type sulfide solid electrolyte materials. Me may include one or more of Si, Ge, Sn, and Al. Optionally, the silver-germanium sulfide type sulfide solid electrolyte material may include materials with the chemical formula Li 6±s P 1-j A j S 5±s-t B t X 1±s The material has the following properties: 0≤j<1, 0≤t<1, 0≤s<1. A includes one or more elements selected from Ge, Si, Sn, and Sb; B includes one or more elements selected from O, Se, and Te; and X includes one or more elements selected from Cl, Br, I, and F. Optionally, LGPS-type sulfide solid electrolyte materials may include those with the chemical formula Li. 10±δ5 Ge 1-g G g P 2-q Q q S 12-w W w The material has the following properties: 0 ≤ δ5 < 1, 0 ≤ g ≤ 1, 0 ≤ q ≤ 2, 0 ≤ w < 1, G includes one or two elements selected from Si and Sn, Q includes Sb, and W includes one or more elements selected from O, Se, Te, Cl, Br, I, and F. As an example, sulfide solid electrolyte materials may include, but are not limited to, Li6PS5Cl, Li6PS5Br, and Li... 10 GeP2S 12 Li3PS4, Li7P3S 11 One or more of them.

[0180] In some embodiments, the thickness of the interface modification layer can be 0.8μm-20μm, for example, it can be 0.8μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, or any range of the above values.

[0181] When the thickness of the interface modification layer is within the above range, the number of inorganic particle stacking layers is large, which can better play the role of uniform ion channels and uniform lithium ion distribution on the negative electrode side during the cycle charging and discharging of the battery cell. This can better uniformize the lithium metal deposition morphology on the negative electrode, reduce dendrite formation and reduce negative electrode volume expansion. It can also better form a framework-like structure near the negative electrode sheet in the later stage of battery cell cycling, promoting the rapid deposition and stripping of lithium ions through the rSEI layer.

[0182] Optionally, the thickness of the interface modification layer can be 1μm-16μm, 1μm-12μm, 1μm-10μm, 1μm-8μm, 1μm-6μm, 2μm-16μm, 2μm-12μm, 2μm-10μm, 2μm-8μm, or 2μm-6μm.

[0183] In some embodiments, the thickness of the interface modification layer can be more than 6 times the volume distribution particle size Dv50 of the inorganic particles.

[0184] The thickness of the interface modification layer is more than 6 times the volume distribution particle size Dv50 of the inorganic particles. At this time, the number of inorganic particle stacking layers is large, which can better play the role of uniform ion channels and uniform lithium ion distribution on the negative electrode side during the cycle charge and discharge of the battery cell. This can better uniformize the lithium metal deposition morphology on the negative electrode, reduce dendrite formation and reduce negative electrode volume expansion. It can also better form a framework-like structure near the negative electrode sheet in the later stage of battery cell cycle, promoting the rapid passage of lithium ions through the rSEI layer for deposition and stripping.

[0185] Optionally, the thickness of the interface modification layer can be more than 10 times the volume distribution particle size Dv50 of the inorganic particles.

[0186] In some embodiments, the negative electrode sheet includes a negative current collector, which may be a metal foil or a composite current collector. The composite current collector may include a polymer material substrate and a metal material layer formed on at least one side of the polymer material substrate.

[0187] Alternatively, as an example, the metal foil may be copper foil, copper alloy foil, nickel foil, nickel alloy foil, aluminum foil, or aluminum alloy foil.

[0188] Optionally, as an example, the metallic material layer may include, but is not limited to, one or more of copper, copper alloys, aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Optionally, as an example, the polymeric material base layer may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0189] In some embodiments, the negative electrode may further include a lithiophilic layer located on at least one side of the negative electrode current collector, and an interface modification layer located between the separator and the lithiophilic layer.

[0190] In some embodiments, the lithiophilic layer may include one or more of a lithiophilic metal, a lithiophilic alloy, and a lithiophilic oxide.

[0191] Optionally, the lithiophilic layer may include one or more of the following: gold (Au), silver (Ag), indium (In), bismuth (Bi), zinc (Zn), tin (Sn), gallium (Ga), and germanium (Ge), in its elemental form, alloy, or oxide.

[0192] In some embodiments, the thickness of the lithiophilic layer can be 20nm-1000nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, or any range of the above values.

[0193] Alternatively, the lithiophilic layer can be formed by an evaporation process or a sputtering process.

[0194] In some embodiments, the negative electrode sheet may include a negative current collector and a lithium-based metal layer located on at least one side of the negative current collector, with an interface modification layer located between the separator and the lithium-based metal layer. The negative current collector may be a metal foil or a composite current collector, and the composite current collector may include a polymer material base layer and a metal material layer formed on at least one side of the polymer material base layer.

[0195] Alternatively, the lithium-based metal layer may include lithium or a lithium alloy.

[0196] In some embodiments, the separator may include a porous base membrane.

[0197] The porous base membrane can be made of one or more of the following materials, including but not limited to glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The porous base membrane can be a single-layer film or a multi-layer composite film. When the porous base membrane is a multi-layer composite film, the materials of each layer may be the same or different.

[0198] In some embodiments, the separator may include a porous base membrane and a heat-resistant coating located on at least one side of the porous base membrane, with an interface modification layer located between the heat-resistant coating and the negative electrode. For example, the interface modification layer may be located between the heat-resistant coating and the lithiophilic layer of the negative electrode, or the interface modification layer may be located between the heat-resistant coating and the lithium-based metal layer of the negative electrode.

[0199] Optionally, the heat-resistant coating may include one or more of organic particles, inorganic particles, and organic-inorganic composite particles.

[0200] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer located on at least one side of the positive current collector, the positive electrode film layer including a positive active material. The positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0201] In some embodiments, the positive electrode active material may include one or more of lithium transition metal oxides and their modified forms, lithium phosphates and their modified forms.

[0202] Optionally, examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and lithium-rich manganese-based materials.

[0203] Optionally, examples of lithium phosphates may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0204] In some embodiments, to further improve the energy density of a single battery cell, the positive electrode active material may include materials of the general formula Li. a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified materials. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M may include one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A may include one or more of N, F, S and Cl.

[0205] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.83 Mn 0.08 Co 0.07 O2 (abbreviated as Ni83), LiNi 0.90 Mn 0.05 Co 0.05 O2 (abbreviated as Ni90), LiNi 0.94 Mn 0.03 Co 0.03 O2 (abbreviated as Ni94), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 One or more of O2, LiFePO4, LiMnPO4 and their respective modified materials.

[0206] During the charging and discharging process, lithium (Li) undergoes insertion / extraction and consumption within a single battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before material addition. As the positive electrode active material is applied to the battery cell, the molar Li content changes after charge-discharge cycles. Similarly, the molar O content in the examples of positive electrode active materials in this disclosure is only a theoretical value. Oxygen release from the crystal lattice causes changes in the molar O content, leading to fluctuations in the actual molar O content.

[0207] The modified materials for the above-mentioned positive electrode active materials can be doped and / or surface coated.

[0208] In some embodiments, the positive electrode film layer may further include a positive electrode binder, which may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0209] In some embodiments, the positive electrode film may further include a positive electrode conductive agent, which may include, but is not limited to, one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers, and vapor-grown carbon fibers (VGCF).

[0210] In some embodiments, the positive current collector may be a metal foil or a composite current collector. Examples of metal foils include carbon-coated aluminum foil, aluminum foil, nickel foil, and titanium foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. Examples of metal materials include, but are not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymer substrates include, but are not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0211] In some embodiments, the battery cell includes an electrolyte. The electrolyte may be a liquid electrolyte, i.e., an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0212] In some embodiments, the electrolyte salt may be one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0213] In some embodiments, the solvent may include, but is not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0214] In some embodiments, the electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve overcharge performance, additives that improve high-temperature performance, additives that improve low-temperature performance, etc.

[0215] In some embodiments, the battery cell includes an outer packaging for housing the electrode assembly and electrolyte. The outer packaging can be a rigid shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging can also be a flexible package, such as a pouch. The flexible package can be made of plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0216] This disclosure also provides a method for preparing the battery cell of this disclosure.

[0217] The method for preparing a battery cell includes the following steps: providing a positive electrode, a negative electrode, a separator, and an electrolyte; providing a slurry comprising a polymer, inorganic particles, and a solvent, wherein the electronic conductivity of the inorganic particles at 25°C is less than 1 S / m, and the polymer includes one or more of polyurethane, polyurea, polyacrylate, and polyamide; coating the slurry onto the surface of the negative electrode and / or separator, and drying it to form a negative electrode and / or separator with an interface modification layer, wherein the interface modification layer comprises inorganic particles and a polymer, the polymer being located on the surface of the inorganic particles and connecting the inorganic particles; assembling the positive electrode, negative electrode, separator, and electrolyte to obtain a battery cell, wherein the separator is located between the positive electrode and the negative electrode, and the negative electrode and / or separator has an interface modification layer located between the separator and the negative electrode.

[0218] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent may include the following steps: reacting a first polyether polyol and a first polyisocyanate at a first temperature for a first time to obtain an NCO-terminated polyurethane prepolymer, and then adding a second polyether polyol and inorganic particles to obtain the slurry.

[0219] The first polyether polyol and the first polyisocyanate react at a first temperature for a first time to obtain an NCO-terminated polyurethane prepolymer through prepolymerization and chain extension. The NCO-terminated polyurethane prepolymer continues to react with the second polyether polyol during slurry preparation, coating, and drying to obtain polyurethane. The polyurethane possesses polyether segments, thus exhibiting good flexibility, encapsulation, and adhesion.

[0220] In some embodiments, the molar ratio of the -OH functional group of the first polyether polyol to the molar ratio of the -NCO functional group of the first polyisocyanate can be from 1:1.01 to 1:1.3, for example, it can be 1:1.01, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, or any range of the above values.

[0221] When the molar ratio of the -OH functional group of the first polyether polyol to the -NCO functional group of the first polyisocyanate is within the above range, the prepared polyurethane can have good flexibility, encapsulation and adhesion.

[0222] In some embodiments, the ratio of the molar amount of the -OH functional group of the first polyether polyol to the molar amount of the sum of the -OH functional groups of the second polyether polyol and the molar amount of the -NCO functional group of the first polyisocyanate (i.e., -OH: -NCO) can be from 1:1 to 1:1.5, for example, 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1... 1:1.09, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48, 1:1.5, or any range of the above values.

[0223] Optionally, the ratio of the molar amount of the -OH functional group of the first polyether polyol to the molar amount of the sum of the -OH functional groups of the second polyether polyol and the molar amount of the -NCO functional group of the first polyisocyanate can be 1:1.01 to 1:1.5, 1:1.02 to 1:1.4, 1:1.02 to 1:1.3, 1:1.02 to 1:1.2, 1:1.02 to 1:1.18, or 1:1.02 to 1:1.16. 1:1.02 to 1:1.14, 1:1.02 to 1:1.12, 1:1.02 to 1:1.1, 1:1.04 to 1:1.4, 1:1.04 to 1:1.3, 1:1.04 to 1:1.2, 1:1.04 to 1:1.18, 1:1.04 to 1:1.16, 1:1.04 to 1:1.14, 1:1.04 to 1:1.12, 1:1.04 to 1:1.1.

[0224] The -NCO functional group reacts with the -OH functional group to obtain the -NHCOO- functional group. When the ratio of the molar amount of the -OH functional group of the first polyether polyol to the molar amount of the sum of the molar amounts of the -OH functional groups of the second polyether polyol and the molar amount of the -NCO functional group of the first polyisocyanate is within the above-mentioned range, the prepared polyurethane has an appropriate amount of unreacted -NCO functional groups. These -NCO functional groups can react with trace amounts of water in the environment and undergo further crosslinking.

[0225] In some embodiments, the viscosity of the first polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0226] In some embodiments, the functionality of the first polyisocyanate may be 2 to 4, optionally 2.

[0227] In some embodiments, the first polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0228] Optionally, the first polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0229] In some embodiments, the viscosity of the first polyether polyol at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0230] Optionally, the viscosity of the first polyether polyol at 25°C can be 1000 mPa·s-30000 mPa·s.

[0231] In some embodiments, the first polyether polyol may include ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0232] In some embodiments, the weight-average molecular weight of the first polyether polyol can be 400-5000.

[0233] In some embodiments, the functionality of the first polyether polyol may be 2 to 4.

[0234] In some embodiments, the first polyether polyol may include one or more of polypropylene glycol, polyethylene glycol, polytetrahydrofuran ether glycol, polypropylene triol, polyethylene triol, polypropylene tetraol, and polyethylene tetraol.

[0235] In some embodiments, the viscosity of the second polyether polyol at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0236] Optionally, the viscosity of the second polyether polyol at 25°C can be 1000 mPa·s-30000 mPa·s.

[0237] In some embodiments, the second polyether polyol may include ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0238] In some embodiments, the weight-average molecular weight of the second polyether polyol can be 400-5000.

[0239] In some embodiments, the functionality of the second polyether polyol may be 2 to 4.

[0240] In some embodiments, the second polyether polyol may include one or more of polypropylene glycol, polyethylene glycol, polytetrahydrofuran ether glycol, polypropylene triol, polyethylene triol, polypropylene tetraol, and polyethylene tetraol.

[0241] In some embodiments, the functionality of the second polyether polyol may be greater than that of the first polyether polyol.

[0242] In some embodiments, the functionality of the first polyisocyanate may be 2, the functionality of the first polyether polyol may be 2, and the functionality of the second polyether polyol may be 3 to 4.

[0243] This allows for the preparation of polyurethane with a three-dimensional cross-linked structure. The cross-linked structure of polyurethane prevents it from dissolving in the electrolyte and reduces its swelling in the electrolyte. This mitigates the problems of rapid increases in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of battery cells, thereby enhancing the long-cycle stability of the battery cells. Furthermore, the prepared polyurethane also exhibits good flexibility, encapsulation, and adhesion.

[0244] In some embodiments, the first polyether polyol may include one or more of polypropylene glycol, polyethylene glycol, and polytetrahydrofuran ether glycol. Optionally, the first polyether polyol may include one or more of N210, N220, N230, N240, N260, and 204.

[0245] In some embodiments, the second polyether polyol may include one or more of polypropylene triol, polyethylene triol, polypropylene tetraol, and polyethylene tetraol. Optionally, the second polyether polyol may include one or more of N330, N310, N3050, N3500, 330N, and 403.

[0246] In some embodiments, the first temperature can be 25°C-80°C.

[0247] In some embodiments, the first time can be 3h-6h.

[0248] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent may include the following steps: reacting a third polyether polyol and a second polyisocyanate at a second temperature for a second time to obtain an OH-terminated polyurethane prepolymer, and then adding the third polyisocyanate and inorganic particles to obtain the slurry.

[0249] The third polyether polyol and the second polyisocyanate react at a second temperature for a second time to obtain an OH-terminated polyurethane prepolymer through prepolymerization and chain extension. The OH-terminated polyurethane prepolymer continues to react with the third polyisocyanate during slurry preparation, coating, and drying to produce polyurethane. Polyurethane possesses polyether segments, thus exhibiting good flexibility, coating properties, and adhesion.

[0250] In some embodiments, the molar ratio of the -OH functional group of the third polyether polyol to the molar ratio of the -NCO functional group of the second polyisocyanate can be from 1.01:1 to 1.2:1, for example, it can be 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1, 1.1:1, 1.11:1, 1.12:1, 1.13:1, 1.14:1, 1.15:1, 1.16:1, 1.17:1, 1.18:1, 1.19:1, 1.2:1, or any range of the above values.

[0251] When the molar ratio of the -OH functional group of the third polyether polyol to the -NCO functional group of the second polyisocyanate is within the above range, the prepared polyurethane can have good flexibility, encapsulation and adhesion.

[0252] In some embodiments, the ratio of the molar amount of the -OH functional group of the third polyether polyol to the sum of the molar amounts of the -NCO functional groups of the second polyisocyanate and the -NCO functional groups of the third polyisocyanate (i.e., -OH: -NCO) can be from 1:1 to 1:1.5, for example, 1:1, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, or 1:1. 09, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48, 1:1.5, or any range of the above values.

[0253] Optionally, the ratio of the molar amount of the -OH functional group of the third polyether polyol to the sum of the molar amounts of the -NCO functional groups of the second polyisocyanate and the -NCO functional groups of the third polyisocyanate can be 1:1.01 to 1:1.5, 1:1.02 to 1:1.4, 1:1.02 to 1:1.3, 1:1.02 to 1:1.2, 1:1.02 to 1:1.18, or 1:1.02 to 1:1.16. , 1:1.02 to 1:1.14, 1:1.02 to 1:1.12, 1:1.02 to 1:1.1, 1:1.04 to 1:1.4, 1:1.04 to 1:1.3, 1:1.04 to 1:1.2, 1:1.04 to 1:1.18, 1:1.04 to 1:1.16, 1:1.04 to 1:1.14, 1:1.04 to 1:1.12, 1:1.04 to 1:1.1.

[0254] The -NCO and -OH functional groups react to form the -NHCOO- functional group. When the molar ratio of the -OH functional group of the third polyether polyol to the sum of the molar ratios of the -NCO functional groups of the second and third polyisocyanates is within the above range, the prepared polyurethane has an appropriate amount of unreacted -NCO functional groups. These -NCO functional groups can react with trace amounts of water in the environment and undergo further crosslinking.

[0255] In some embodiments, the viscosity of the third polyether polyol at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0256] Optionally, the viscosity of the third polyether polyol at 25°C can be 1000 mPa·s-30000 mPa·s.

[0257] In some embodiments, the third polyether polyol may include ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or a water-based polyether polyol.

[0258] In some embodiments, the weight-average molecular weight of the third polyether polyol can be 400-5000.

[0259] In some embodiments, the functionality of the third polyether polyol can be 2 to 4, optionally 2.

[0260] In some embodiments, the second polyether polyol may include one or more of polypropylene glycol, polyethylene glycol, polytetrahydrofuran ether glycol, polypropylene triol, polyethylene triol, polypropylene tetraol, and polyethylene tetraol.

[0261] In some embodiments, the third polyether polyol may include one or more of N210, N220, N230, N240, N260, 204, N330, N310, N3050, N3500, 330N, and 403.

[0262] Optionally, the third polyether polyol may include one or more of polypropylene glycol, polyethylene glycol, and polytetrahydrofuran ether glycol. Optionally, the third polyether polyol may include one or more of N210, N220, N230, N240, N260, and 204.

[0263] In some embodiments, the viscosity of the second polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0264] In some embodiments, the functionality of the second polyisocyanate may be 2 to 4.

[0265] In some embodiments, the viscosity of the third polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0266] In some embodiments, the functionality of the third polyisocyanate can be 2 to 4.

[0267] In some embodiments, the functionality of the third polyisocyanate may be greater than that of the second polyisocyanate.

[0268] In some embodiments, the functionality of the third polyether polyol may be 2, the functionality of the second polyisocyanate may be 2, and the functionality of the third polyisocyanate may be 3 to 4.

[0269] This allows for the preparation of polyurethane with a three-dimensional cross-linked structure. The cross-linked structure of polyurethane prevents it from dissolving in the electrolyte and reduces its swelling in the electrolyte. This mitigates the problems of rapid increases in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of battery cells, thereby enhancing the long-cycle stability of the battery cells. Furthermore, the prepared polyurethane also exhibits good flexibility, encapsulation, and adhesion.

[0270] In some embodiments, the second polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0271] In some embodiments, the third polyisocyanate may include one or more of hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0272] In some embodiments, the second temperature can be 25°C-80°C.

[0273] In some embodiments, the second time may be 3h-6h.

[0274] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent may include the following steps: reacting a first polyether polyamine and a fourth polyisocyanate at a third temperature for a third time to obtain an NCO-terminated polyurea prepolymer, and then adding a second polyether polyamine and inorganic particles to obtain the slurry.

[0275] The first polyether polyamine and the fourth polyisocyanate react at a third temperature for a third time to obtain an NCO-terminated polyurea prepolymer through prepolymerization and chain extension. The NCO-terminated polyurea prepolymer then reacts with the second polyether polyamine during slurry preparation, coating, and drying to produce a polyurea. The polyurea possesses polyether segments, thus exhibiting good flexibility, coating properties, and adhesion.

[0276] In some embodiments, the molar ratio of the -NH2 functional group of the first polyether polyamine to the molar ratio of the -NCO functional group of the fourth polyisocyanate can be from 1:1.01 to 1:1.3, for example, it can be 1:1.01, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, or any range of the above values.

[0277] When the ratio of the molar amount of the -NH2 functional group of the first polyether polyamine to the molar amount of the -NCO functional group of the fourth polyisocyanate is within the above range, the prepared polyurea can have good flexibility, coating and adhesion.

[0278] In some embodiments, the ratio of the molar amount of the -NH2 functional group of the first polyether polyamine and the sum of the molar amounts of the -NH2 functional groups of the second polyether polyamine to the molar amount of the -NCO functional group of the fourth polyisocyanate (i.e., -NH2:-NCO) can be from 1:1 to 1:1.5, for example, it can be 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48, 1:1.5, or any range of the above values.

[0279] Optionally, the ratio of the molar amount of the -NH2 functional group of the first polyether polyamine to the molar amount of the -NH2 functional group of the second polyether polyamine to the molar amount of the -NCO functional group of the fourth polyisocyanate can be 1:1.01 to 1:1.5, 1:1.02 to 1:1.4, 1:1.02 to 1:1.3, 1:1.02 to 1:1.2, 1:1.02 to 1:1.18, or 1:1.02 to 1:1.16. , 1:1.02 to 1:1.14, 1:1.02 to 1:1.12, 1:1.02 to 1:1.1, 1:1.04 to 1:1.4, 1:1.04 to 1:1.3, 1:1.04 to 1:1.2, 1:1.04 to 1:1.18, 1:1.04 to 1:1.16, 1:1.04 to 1:1.14, 1:1.04 to 1:1.12, 1:1.04 to 1:1.1.

[0280] The -NCO and -NH2 functional groups react to form the -NHCONH- functional group. When the ratio of the sum of the molar amounts of the -NH2 functional groups of the first polyether polyamine and the second polyether polyamine to the molar amount of the -NCO functional group of the fourth polyisocyanate is within the above range, the prepared polyurea has an appropriate amount of unreacted -NCO functional groups. These -NCO functional groups can react with trace amounts of water in the environment and undergo further crosslinking.

[0281] In some embodiments, the viscosity of the fourth polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0282] In some embodiments, the functionality of the fourth polyisocyanate can be 2 to 4, optionally 2.

[0283] In some embodiments, the fourth polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0284] Optionally, the fourth polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0285] In some embodiments, the viscosity of the first polyether polyamine at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0286] Optionally, the viscosity of the first polyether polyamine at 25°C can be 1000 mPa·s-30000 mPa·s.

[0287] In some embodiments, the weight-average molecular weight of the first polyether polyamine can be 200-8000.

[0288] In some embodiments, the functionality of the first polyether polyamine can be 2 to 4.

[0289] In some embodiments, the viscosity of the second polyether polyamine at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0290] Optionally, the viscosity of the second polyether polyamine at 25°C can be 1000 mPa·s-30000 mPa·s.

[0291] In some embodiments, the weight-average molecular weight of the second polyether polyamine can be 200-8000.

[0292] In some embodiments, the functionality of the second polyether polyamine can be 2 to 4.

[0293] In some embodiments, the functionality of the second polyether polyamine may be greater than that of the first polyether polyamine.

[0294] In some embodiments, the functionality of the fourth polyisocyanate may be 2, the functionality of the first polyether polyamine may be 2, and the functionality of the second polyether polyamine may be 3 to 4.

[0295] This allows for the preparation of polyurea with a three-dimensional cross-linked structure. The cross-linked structure of polyurea prevents it from dissolving in the electrolyte and reduces its swelling in the electrolyte. This mitigates the problems of rapid increases in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of battery cells, thus enhancing the long-cycle stability of the battery cells. Furthermore, the prepared polyurea also exhibits good flexibility, coating properties, and adhesion.

[0296] In some embodiments, the first polyether polyamine may include one or more of D2000, D400, and D230.

[0297] In some embodiments, the second polyether polyamine may include one or more of T5000 and T403.

[0298] In some embodiments, the third temperature can be 25°C-80°C.

[0299] In some embodiments, the third time can be 3h-6h.

[0300] In some embodiments, the step of providing a slurry comprising a polymer, inorganic particles, and a solvent may include the following steps: reacting a third polyether polyamine and a fifth polyisocyanate at a fourth temperature for a fourth time to obtain an NH2-terminated polyurea prepolymer, and then adding a sixth polyisocyanate and inorganic particles to obtain the slurry.

[0301] The third polyether polyamine and the fifth polyisocyanate are reacted at a fourth temperature for a fourth time to obtain an NH2-terminated polyurea prepolymer through prepolymerization and chain extension. The NH2-terminated polyurea prepolymer is then reacted with the sixth polyisocyanate during slurry preparation, coating, and drying to produce polyurea. Polyurea possesses polyether segments, thus exhibiting good flexibility, coating properties, and adhesion.

[0302] In some embodiments, the molar ratio of the -NH2 functional group of the third polyether polyamine to the molar ratio of the -NCO functional group of the fifth polyisocyanate can be from 1.01:1 to 1.2:1, for example, it can be 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1, 1.1:1, 1.11:1, 1.12:1, 1.13:1, 1.14:1, 1.15:1, 1.16:1, 1.17:1, 1.18:1, 1.19:1, 1.2:1, or any range of the above values.

[0303] When the molar ratio of the -NH2 functional group of the third polyether polyamine to the -NCO functional group of the fifth polyisocyanate is within the above range, the prepared polyurea can have good flexibility, coating and adhesion.

[0304] In some embodiments, the ratio of the molar amount of the -NH2 functional group of the third polyether polyamine to the sum of the molar amounts of the -NCO functional groups of the fifth and sixth polyisocyanates (i.e., -NH2:-NCO) can be from 1:1 to 1:1.5, for example, 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48, 1:1.5, or any range of the above values.

[0305] Optionally, the ratio of the molar amount of the -NH2 functional group of the third polyether polyamine to the sum of the molar amounts of the -NCO functional groups of the fifth and sixth polyisocyanates can be 1:1.01 to 1:1.5, 1:1.02 to 1:1.4, 1:1.02 to 1:1.3, 1:1.02 to 1:1.2, 1:1.02 to 1:1.18, or 1:1.02 to 1:1.16. , 1:1.02 to 1:1.14, 1:1.02 to 1:1.12, 1:1.02 to 1:1.1, 1:1.04 to 1:1.4, 1:1.04 to 1:1.3, 1:1.04 to 1:1.2, 1:1.04 to 1:1.18, 1:1.04 to 1:1.16, 1:1.04 to 1:1.14, 1:1.04 to 1:1.12, 1:1.04 to 1:1.1.

[0306] The -NCO and -NH2 functional groups react to form the -NHCONH- functional group. When the ratio of the molar amount of the -NH2 functional group in the third polyether polyamine to the sum of the molar amounts of the -NCO functional groups in the fifth and sixth polyisocyanates is within the above range, the prepared polyurea has an appropriate amount of unreacted -NCO functional groups. These -NCO functional groups can react with trace amounts of water in the environment and undergo further crosslinking.

[0307] In some embodiments, the viscosity of the third polyether polyamine at 25°C can be between 10 mPa·s and 100,000 mPa·s, for example, it can be 10 mPa·s, 100 mPa·s, 500 mPa·s, 1000 mPa·s, 2000 mPa·s, 4000 mPa·s, 6000 mPa·s, 8000 mPa·s, 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 16000 mPa·s, 18000 mPa·s, 20000 mPa·s, 22000 mPa·s. 24000 mPa·s, 26000 mPa·s, 28000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 100000 mPa·s, or any range of the above values.

[0308] Optionally, the viscosity of the third polyether polyamine at 25°C can be 1000 mPa·s-30000 mPa·s.

[0309] In some embodiments, the weight-average molecular weight of the third polyether polyamine can be 200-8000.

[0310] In some embodiments, the functionality of the third polyether polyamine can be 2 to 4, optionally 2.

[0311] In some embodiments, the third polyether polyamine may include one or more of D2000, D400, D230, T5000, and T403.

[0312] Optionally, the third polyether polyamine may include one or more of D2000, D400, and D230.

[0313] In some embodiments, the viscosity of the fifth polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0314] In some embodiments, the functionality of the fifth polyisocyanate can be 2 to 4.

[0315] In some embodiments, the viscosity of the sixth polyisocyanate at 25°C can be between 10 mPa·s and 1000 mPa·s, for example, 10 mPa·s, 20 mPa·s, 40 mPa·s, 60 mPa·s, 80 mPa·s, 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s. 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0316] In some embodiments, the functionality of the sixth polyisocyanate can be 2 to 4.

[0317] In some embodiments, the functionality of the sixth polyisocyanate may be greater than that of the fifth polyisocyanate.

[0318] In some embodiments, the functionality of the third polyether polyamine may be 2, the functionality of the fifth polyisocyanate may be 2, and the functionality of the sixth polyisocyanate may be 3 to 4.

[0319] This allows for the preparation of polyurea with a three-dimensional cross-linked structure. The cross-linked structure of polyurea prevents it from dissolving in the electrolyte and reduces its swelling in the electrolyte. This mitigates the problems of rapid increases in electrolyte viscosity and sudden deterioration of electrolyte wettability at the negative electrode interface during long-term use of battery cells, thus enhancing the long-cycle stability of the battery cells. Furthermore, the prepared polyurea also exhibits good flexibility, coating properties, and adhesion.

[0320] In some embodiments, the fifth polyisocyanate may include one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate.

[0321] In some embodiments, the sixth polyisocyanate may include one or more of hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

[0322] In some embodiments, the fourth temperature can be 25°C-80°C.

[0323] In some embodiments, the fourth time may be 3h-6h.

[0324] In some embodiments, the solvent for the slurry may include one or more of N-methylpyrrolidone (NMP) and tetrahydrofuran (THF).

[0325] In some embodiments, the viscosity of the slurry at 25°C can be between 100 mPa·s and 1000 mPa·s, for example, it can be 100 mPa·s, 120 mPa·s, 140 mPa·s, 160 mPa·s, 180 mPa·s, 200 mPa·s, 220 mPa·s, 240 mPa·s, 260 mPa·s, 280 mPa·s, 300 mPa·s, 320 mPa·s, 340 mPa·s, 360 mPa·s, 380 mPa·s, 400 mPa·s, 420 mPa·s, 440 mPa·s, 460 mPa·s, 480 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, 900 mPa·s, 1000 mPa·s, or any range of the above values.

[0326] Optionally, the viscosity of the slurry at 25°C can be 200 mPa·s-500 mPa·s.

[0327] In some embodiments, the solid content of the slurry can be 10%-60%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any range of the above values.

[0328] Optionally, the solid content of the slurry can be 20%-50%.

[0329] Example

[0330] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0331] Example 1

[0332] Preparation of positive electrode sheet

[0333] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, polyvinylidene fluoride (PVDF) as the positive electrode binder, and acetylene black as the positive electrode conductive agent are mixed in a mass ratio of 98:1:1, and N-methylpyrrolidone (NMP) is added and stirred to form a uniform positive electrode slurry. The positive electrode slurry is then uniformly coated on both surfaces of the positive electrode current collector aluminum foil, with a positive electrode active material loading of 25 mg / cm³. 2 After drying and cold pressing, the material is cut into rectangular plates of 40mm×50mm to serve as positive electrode plates.

[0334] Preparation of negative electrode sheet

[0335] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0336] Add 91.21g of polyether polyol N230 (0.0304mol) and 8.79g of isophorone diisocyanate IPDI (0.0395mol) to 100g In N-methylpyrrolidone (NMP), nitrogen gas was passed through the liquid surface for 1 hour, and then the gas tube was removed. The mixture was heated to 70°C and reacted for 4 hours to obtain an NCO-terminated polyurethane prepolymer solution. After removing the NCO-terminated polyurethane prepolymer solution, 1144.4 g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2 μm and 14.44 g of polyether polyol N330 (0.0047 mol) were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60°C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer with a thickness of 4 μm.

[0337] Preparation of the separating membrane

[0338] A porous polypropylene membrane with a thickness of 12μm was used, and then cut into 44mm×54mm sheets as a separator.

[0339] Preparation of electrolyte

[0340] The electrolyte solvent is a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7, and the lithium salt is lithium hexafluorophosphate (LiPF6) with a concentration of 1 mol / L.

[0341] Preparation of battery cells

[0342] One cut positive electrode sheet and two negative electrode sheets are matched, and two separator films are placed between the positive and negative electrodes to isolate them. Then, the positive and negative electrodes are welded together and wrapped in an outer aluminum-plastic film bag. After that, 0.3g of electrolyte is injected, and the aluminum-plastic film is vacuum heat-pressed and sealed. Then, it is left to stand at 25°C for 8 hours to obtain a single battery cell with a capacity of 140mAh.

[0343] Comparative Example 1

[0344] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0345] Preparation of negative electrode sheet

[0346] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrodes of 42mm×52mm to serve as negative electrodes.

[0347] Comparative Example 2

[0348] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0349] Preparation of negative electrode sheet

[0350] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0351] 91.21 g of polyether polyol N230 (0.0304 mol) and 8.79 g of isophorone diisocyanate IPDI (0.0395 mol) were added to 100 g of N-methylpyrrolidone (NMP). Nitrogen gas was passed through the liquid for 1 hour, and then the gas tube was removed. The mixture was heated to 70 °C and reacted for 4 hours to obtain an NCO-terminated polyurethane prepolymer solution. The NCO-terminated polyurethane prepolymer solution was removed and 14.44 g of polyether polyol N330 (0.0047 mol) was added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60 °C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer of 4 μm thickness.

[0352] Comparative Example 3

[0353] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0354] Preparation of negative electrode sheet

[0355] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0356] Inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2 μm and polyvinylidene fluoride were mixed evenly at a mass ratio of 95:5. An appropriate amount of N-methylpyrrolidone (NMP) was added and stirred evenly to obtain a slurry with a viscosity of 300 mPa·s. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in an oven at 60℃ for 12 h to obtain a negative electrode sheet with an interface modification layer with a thickness of 4 μm.

[0357] Performance testing

[0358] Cyclic performance tests were conducted on individual battery cells at 25°C using a 0.2C (28mA) charge and a 1C (140mA) discharge rate. Specifically, the battery cells were charged at a constant current rate of 0.2C to 4.3V, followed by constant voltage charging until the current decayed to 0.15C; then discharged at a constant current rate of 1C to a voltage of 2.8V to obtain the first discharge capacity; subsequent charge-discharge cycles were performed following the same steps.

[0359] Table 1

[0360] The test results above show that the battery cell of this disclosure still has a high discharge capacity after 100 cycles. This is because the interface modification layer includes inorganic particles and polymers. The inorganic particles can act as uniform ion channels on the negative electrode side, improving the uniform distribution of lithium ions on the negative electrode side, thereby uniformly morphologically depositing lithium metal on the negative electrode, reducing dendrite formation and decreasing negative electrode volume expansion. The polymer can improve the wettability of the electrolyte at the negative electrode interface and bind the electrolyte. Therefore, the battery cell of this disclosure can have good cycle stability.

[0361] In Comparative Example 2, no inorganic particles were added to the interface modification layer, resulting in poor lithium metal deposition morphology and large volume expansion in the negative electrode, which led to a low discharge capacity of the battery cell after 100 cycles.

[0362] The polymer polyvinylidene fluoride used in the interface modification layer of Comparative Example 3 could not effectively improve the wettability of the electrolyte at the negative electrode interface and the binding of the electrolyte, resulting in a low discharge capacity of the battery cell after 100 cycles.

[0363] Example 2

[0364] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0365] Preparation of negative electrode sheet

[0366] The thickness of the interface modification layer is 2μm.

[0367] Example 3

[0368] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0369] Preparation of negative electrode sheet

[0370] The thickness of the interface modification layer is 6μm.

[0371] Table 2

[0372] As can be seen from the test results of Examples 1 to 3, further adjusting the thickness of the interface modification layer can further improve the cycle capacity of lithium metal battery cells.

[0373] Example 4

[0374] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0375] Preparation of negative electrode sheet

[0376] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0377] Add 94.18g of polyether polyol N230 (0.0314mol) and 5.82g of isophorone diisocyanate IPDI (0.0262mol) to 100g In N-methylpyrrolidone (NMP), nitrogen gas was passed through the liquid surface for 1 hour, and then the gas tube was removed. The mixture was heated to 70°C and reacted for 4 hours to obtain a polyurethane prepolymer solution with OH-terminated ends. After removing the polyurethane prepolymer solution with OH-terminated ends, 1022.8 g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 200 nm and 2.28 g of hexamethylene diisocyanate (HDI) trimer (0.0045 mol) were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60°C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer with a thickness of 4 μm.

[0378] Example 5

[0379] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0380] Preparation of negative electrode sheet

[0381] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0382] 94.18 g of polyether polyol N230 (0.0314 mol) and 5.82 g of isophorone diisocyanate IPDI (0.0262 mol) were added to 100 g of N-methylpyrrolidone (NMP). Nitrogen gas was passed through the liquid for 1 hour, and then the gas tube was removed. The mixture was heated to 70 °C and reacted for 4 hours to obtain an OH-terminated polyurethane prepolymer solution. After removing the OH-terminated polyurethane prepolymer solution, 1000 g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2 μm were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60 °C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer of 4 μm thickness.

[0383] Example 6

[0384] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0385] Preparation of negative electrode sheet

[0386] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0387] Add 91.21g of polyether polyol N230 (0.0304mol) and 8.79g of isophorone diisocyanate IPDI (0.0395mol) to 100g In N-methylpyrrolidone (NMP), nitrogen gas was passed through the liquid surface for 1 hour, and then the gas tube was removed. The mixture was heated to 70°C and reacted for 4 hours to obtain an NCO-terminated polyurethane prepolymer solution. After removing the NCO-terminated polyurethane prepolymer solution, 1183g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2μm and 18.3g of polyether polyol N330 (0.0061mol) were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60°C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer of 4μm thickness.

[0388] Example 7

[0389] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0390] Preparation of negative electrode sheet

[0391] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0392] Add 91.21g of polyether polyol N230 (0.0304mol) and 8.79g of isophorone diisocyanate IPDI (0.0395mol) to 100g In N-methylpyrrolidone (NMP), nitrogen gas was passed through the liquid surface for 1 hour, and then the gas tube was removed. The mixture was heated to 70°C and reacted for 4 hours to obtain an NCO-terminated polyurethane prepolymer solution. After removing the NCO-terminated polyurethane prepolymer solution, 1050.3 g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2 μm and 5.03 g of polyether polyol N330 (0.0017 mol) were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60°C oven for 12 hours to obtain a negative electrode sheet with an interface modification layer of 4 μm thickness.

[0393] Example 8

[0394] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0395] Preparation of negative electrode sheet

[0396] Two 50μm thick lithium foils are combined with copper foil by rolling, and then cut into rectangular electrode sheets of 42mm×52mm.

[0397] 12.16g of polyether polyamine D400 (0.0304mol) and 8.79g of isophorone diisocyanate IPDI (0.0395mol) were added to 21g of [amount missing]. In N-methylpyrrolidone (NMP), nitrogen gas was passed through the liquid surface for 1 hour, then the gas tube was removed, and the reaction was carried out at room temperature (25℃) for 3 hours, followed by a reaction at 60℃ for 1 hour to obtain an NCO-terminated polyurea prepolymer solution. After removing the NCO-terminated polyurea prepolymer solution, 446.2 g of inorganic particles SiO2 with a volume distribution particle size Dv50 of 0.2 μm and 23.67 g of polyether polyamine T5000 (0.0047 mol) were added and mixed evenly. Then, an appropriate amount of N-methylpyrrolidone (NMP) was added to dilute to the target viscosity of 300 mPa·s to obtain a slurry. An appropriate amount of the slurry was then coated onto the surface of a lithium foil and dried in a 60℃ oven for 12 hours to obtain a negative electrode sheet with an interface modification layer of 4 μm thickness.

[0398] Table 3

[0399] As can be seen from the test results of Examples 1, 4 to 8, the polymer with cross-linked structure can enable the battery cell to have high discharge capacity after 100 cycles, and enable the battery cell to have long cycle stability.

[0400] The test results above show that polyurethane or polyurea, with an appropriate amount of unreacted -NCO functional groups, can enable battery cells to have higher discharge capacity after 100 cycles, thus providing long-term cycle stability. This is because the -NCO functional groups can react with trace amounts of water in the environment and undergo further cross-linking, enhancing the stability of the polymer.

[0401] Example 9

[0402] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0403] Preparation of negative electrode sheet

[0404] The inorganic particles SiO2 were replaced with α-Al2O3, and the volume distribution particle size Dv50 was 0.3 μm.

[0405] Example 10

[0406] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0407] Preparation of negative electrode sheet

[0408] The inorganic particles SiO2 were replaced with ZrO2, and the volume distribution particle size Dv50 was 0.3 μm.

[0409] Table 4

[0410] The test results of Examples 1, 9, and 10 show that different types of inorganic particles have different effects on improving the cycle performance of battery cells.

[0411] Example 11

[0412] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0413] Preparation of negative electrode sheet

[0414] The amount of inorganic particles used was 1487.7g, and the mass ratio of inorganic particles to polymer was 13:1.

[0415] Example 12

[0416] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0417] Preparation of negative electrode sheet

[0418] The amount of inorganic particles used was 1831.04g, and the mass ratio of inorganic particles to polymer was 16:1.

[0419] Example 13

[0420] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0421] Preparation of negative electrode sheet

[0422] The amount of inorganic particles used is 801.1g, and the mass ratio of inorganic particles to polymer is 7:1.

[0423] Example 14

[0424] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0425] Preparation of negative electrode sheet

[0426] The amount of inorganic particles used is 572.2g, and the mass ratio of inorganic particles to polymer is 5:1.

[0427] Table 5

[0428] As can be seen from the test results of Examples 1 and 11 to 14, further adjusting the mass ratio of inorganic particles and polymers in the interface modification layer can further improve the cycle capacity of lithium metal battery cells.

[0429] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this disclosure are included within the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included within the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A battery cell, comprising an electrode assembly, the electrode assembly including a positive electrode, a negative electrode, and a separator, the separator being located between the positive electrode and the negative electrode, wherein, The battery cell further includes an interface modification layer located between the separator and the negative electrode. The interface modification layer includes inorganic particles and a polymer. The polymer is located on the surface of the inorganic particles and connects the inorganic particles. The inorganic particles have an electronic conductivity of less than 1 S / m at 25°C. The polymer includes one or more of polyurethane, polyurea, polyacrylate, and polyamide.

2. The battery cell of claim 1, wherein, The polymer includes one or more of polyurethane and polyurea.

3. The battery cell of any one of claims 1-2, wherein, The polymer has a cross-linked structure.

4. The battery cell according to any one of claims 1-3, wherein, The polyurethane satisfies one or more of the following conditions (1) to (2): (1) The polyurethane has -NHCOO- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional group to the -NHCOO- functional group is 0.01:1 to 0.5:

1. (2) The polyurethane has polyether segments; The polyurea satisfies one or more of the following conditions (3) to (4): (3) The polyurea has -NHCONH- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional group to the -NHCONH- functional group is 0.01:1 to 0.5:

1. (4) The polyurea has polyether segments.

5. The battery cell according to claim 4, wherein, The polyurethane has -NHCOO- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional groups to the -NHCOO- functional groups is 0.02:1 to 0.1:1; and / or, The polyurea has -NHCONH- functional groups and -NCO functional groups, and the molar ratio of the -NCO functional group to the -NHCONH- functional group is 0.02:1 to 0.1:

1.

6. The battery cell according to any one of claims 1-5, wherein, The mass ratio of the polymer to the inorganic particles is 1:4 to 1:

19.

7. The battery cell according to claim 6, wherein, The mass ratio of the polymer to the inorganic particles is 1:7 to 1:

13.

8. The battery cell according to any one of claims 1-7, wherein, The thickness of the interface modification layer is 0.8 μm-20 μm; and / or, The inorganic particles have a volume distribution particle size Dv50 of 0.02 μm-0.5 μm; and / or, The thickness of the interface modification layer is more than 6 times the volume distribution particle size Dv50 of the inorganic particles.

9. The battery cell according to claim 8, wherein, The thickness of the interface modification layer is 2μm-6μm; and / or, The inorganic particles have a volume distribution particle size Dv50 of 0.1 μm-0.3 μm.

10. The battery cell according to any one of claims 1-9, wherein, The inorganic particles include one or more of ceramics and inorganic solid electrolyte materials; and / or, The inorganic particles include one or more of the following: solid structure, porous structure, and hollow structure; and / or, The inorganic particles have hydroxyl groups on their surface.

11. The battery cell according to any one of claims 1-10, wherein, The negative electrode sheet includes a negative current collector, which is a metal foil or a composite current collector. The composite current collector includes a polymer material base layer and a metal material layer formed on at least one side of the polymer material base layer.

12. The battery cell according to claim 11, wherein, The negative electrode sheet further includes a lithiophilic layer located on at least one side of the negative electrode current collector, and the interface modification layer is located between the separator and the lithiophilic layer.

13. The battery cell according to any one of claims 1-10, wherein, The negative electrode sheet includes a negative current collector and a lithium-based metal layer located on at least one side of the negative current collector. The interface modification layer is located between the separator and the lithium-based metal layer. The negative current collector is a metal foil or a composite current collector. The composite current collector includes a polymer material base layer and a metal material layer formed on at least one side of the polymer material base layer.

14. The battery cell according to any one of claims 1-13, wherein, The isolation membrane comprises a porous base membrane.

15. The battery cell according to any one of claims 1-13, wherein, The separator includes a porous base membrane and a heat-resistant coating located on at least one side of the porous base membrane. The interface modification layer is located between the heat-resistant coating and the negative electrode sheet. The heat-resistant coating includes one or more of organic particles, inorganic particles, and organic-inorganic composite particles.

16. A method for preparing a single battery cell, comprising the following steps: We provide positive electrode plates, negative electrode plates, separator membranes, and electrolytes. A slurry comprising a polymer, inorganic particles, and a solvent is provided, wherein the inorganic particles have an electronic conductivity of less than 1 S / m at 25°C, and the polymer comprises one or more of polyurethane, polyurea, polyacrylate, and polyamide. The slurry is coated on the surface of the negative electrode sheet and / or the separator, and after drying, a negative electrode sheet and / or separator with an interface modification layer is formed. The interface modification layer includes inorganic particles and a polymer, and the polymer is located on the surface of the inorganic particles and connects the inorganic particles. The positive electrode, the negative electrode, the separator, and the electrolyte are assembled to form a battery cell. The separator is located between the positive electrode and the negative electrode. The negative electrode and / or the separator has the interface modification layer, and the interface modification layer is located between the separator and the negative electrode.

17. The preparation method according to claim 16, wherein, The steps for providing a slurry comprising polymers, inorganic particles, and solvents include the following: The first polyether polyol and the first polyisocyanate are reacted at a first temperature for a first time to obtain an NCO-terminated polyurethane prepolymer. Then, the second polyether polyol and inorganic particles are added to obtain a slurry. Alternatively, the third polyether polyol and the second polyisocyanate are reacted at a second temperature for a second time to obtain an OH-terminated polyurethane prepolymer, and then the third polyisocyanate and inorganic particles are added to obtain a slurry; Alternatively, the first polyether polyamine and the fourth polyisocyanate are reacted at a third temperature for a third time to obtain an NCO-terminated polyurea prepolymer, and then the second polyether polyamine and inorganic particles are added to obtain a slurry. Alternatively, the third polyether polyamine and the fifth polyisocyanate are reacted at a fourth temperature for a fourth time to obtain an NH2-terminated polyurea prepolymer, and then a sixth polyisocyanate and inorganic particles are added to obtain a slurry.

18. The preparation method according to claim 17, wherein, The step of providing a slurry comprising a polymer, inorganic particles and a solvent satisfies one or more of the following conditions (1) to (16): (1) The molar ratio of the -OH functional group of the first polyether polyol to the molar ratio of the -NCO functional group of the first polyisocyanate is 1:1.01 to 1:1.3; (2) The ratio of the sum of the molar amounts of the -OH functional groups of the first polyether polyol and the -OH functional groups of the second polyether polyol to the molar amounts of the -NCO functional groups of the first polyisocyanate is 1:1.01 to 1:1.5, and optionally 1:1.02 to 1:1.

1. (3) The first temperature is 25℃-80℃; (4) The first time period is 3h-6h; (5) The molar ratio of the -OH functional group of the third polyether polyol to the molar ratio of the -NCO functional group of the second polyisocyanate is 1.01:1 to 1.2:1; (6) The ratio of the molar amount of the -OH functional group of the third polyether polyol to the sum of the molar amounts of the -NCO functional group of the second polyisocyanate and the -NCO functional group of the third polyisocyanate is 1:1.01 to 1:1.5, and optionally 1:1.02 to 1:1.

1. (7) The second temperature is 25℃-80℃; (8) The second time is 3h-6h; (9) The molar ratio of the -NH2 functional group of the first polyether polyamine to the molar ratio of the -NCO functional group of the fourth polyisocyanate is 1:1.01 to 1:1.3; (10) The ratio of the sum of the molar amounts of the -NH2 functional groups of the first polyether polyamine and the -NH2 functional groups of the second polyether polyamine to the molar amounts of the -NCO functional groups of the fourth polyisocyanate is 1:1.01 to 1:1.5, and optionally 1:1.02 to 1:1.

1. (11) The third temperature is 25℃-80℃; (12) The third time period is 3h-6h; (13) The molar ratio of the -NH2 functional group of the third polyether polyamine to the molar ratio of the -NCO functional group of the fifth polyisocyanate is 1.01:1 to 1.2:1; (14) The ratio of the molar amount of the -NH2 functional group of the third polyether polyamine to the sum of the molar amounts of the -NCO functional groups of the fifth polyisocyanate and the -NCO functional groups of the sixth polyisocyanate is 1:1.01 to 1:1.5, and optionally 1:1.02 to 1:1.

1. (15) The fourth temperature is 25℃-80℃; (16) The fourth time is 3h-6h.

19. The preparation method according to any one of claims 17-18, wherein, The step of providing a slurry comprising a polymer, inorganic particles and a solvent satisfies one or more of the following conditions (1) to (18): (1) The viscosity of the first polyether polyol at 25°C is 10 mPa·s-100000 mPa·s; (2) The weight-average molecular weight of the first polyether polyol is 400-5000; (3) The viscosity of the second polyether polyol at 25°C is 10 mPa·s-100000 mPa·s; (4) The weight-average molecular weight of the second polyether polyol is 400-5000; (5) The viscosity of the third polyether polyol at 25°C is 10 mPa·s-100000 mPa·s; (6) The weight-average molecular weight of the third polyether polyol is 400-5000; (7) The viscosity of the first polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s; (8) The weight-average molecular weight of the first polyether polyamine is 200-8000; (9) The viscosity of the second polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s; (10) The weight-average molecular weight of the second polyether polyamine is 200-8000; (11) The viscosity of the third polyether polyamine at 25°C is 10 mPa·s-100000 mPa·s; (12) The weight-average molecular weight of the third polyether polyamine is 200-8000; (13) The viscosity of the first polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s; (14) The viscosity of the second polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s; (15) The viscosity of the third polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s; (16) The viscosity of the fourth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s; (17) The viscosity of the fifth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s; (18) The viscosity of the sixth polyisocyanate at 25°C is 10 mPa·s-1000 mPa·s.

20. The preparation method according to any one of claims 17-19, wherein, The step of providing a slurry comprising a polymer, inorganic particles and a solvent satisfies one or more of the following conditions (1) to (15): (1) The first polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or water-based polyether polyol; (2) The functionality of the first polyether polyol is 2 to 4; (3) The second polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or water-based polyether polyol; (4) The functionality of the second polyether polyol is 2 to 4; (5) The third polyether polyol includes ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, glucose, sucrose, toluene diamine, ethylenediamine, or water-based polyether polyols. (6) The functionality of the third polyether polyol is 2 to 4; (7) The functionality of the first polyether polyamine is 2 to 4; (8) The functionality of the second polyether polyamine is 2 to 4; (9) The functionality of the third polyether polyamine is 2 to 4; (10) The functionality of the first polyisocyanate is 2 to 4; (11) The functionality of the second polyisocyanate is 2 to 4; (12) The functionality of the third polyisocyanate is 2 to 4; (13) The functionality of the fourth polyisocyanate is 2 to 4; (14) The functionality of the fifth polyisocyanate is 2 to 4; (15) The sixth polyisocyanate has a functionality of 2 to 4.

21. The preparation method according to any one of claims 17-20, wherein, The step of providing a slurry comprising a polymer, inorganic particles and a solvent satisfies one or more of the following conditions (1) to (8): (1) The functionality of the second polyether polyol is greater than that of the first polyether polyol. (2) The first polyisocyanate has a functionality of 2, the first polyether polyol has a functionality of 2, and the second polyether polyol has a functionality of 3 to 4. (3) The functionality of the third polyisocyanate is greater than that of the second polyisocyanate; (4) The third polyether polyol has a functionality of 2, the second polyisocyanate has a functionality of 2, and the third polyisocyanate has a functionality of 3 to 4. (5) The functionality of the second polyether polyamine is greater than that of the first polyether polyamine. (6) The fourth polyisocyanate has a functionality of 2, the first polyether polyamine has a functionality of 2, and the second polyether polyamine has a functionality of 3 to 4. (7) The functionality of the sixth polyisocyanate is greater than that of the fifth polyisocyanate; (8) The third polyether polyamine has a functionality of 2, the fifth polyisocyanate has a functionality of 2, and the sixth polyisocyanate has a functionality of 3 to 4.

22. The preparation method according to any one of claims 17-21, wherein, The step of providing a slurry comprising a polymer, inorganic particles and a solvent satisfies one or more of the following conditions (1) to (12): (1) The first polyether polyol includes one or more of N210, N220, N230, N240, N260, and 204; (2) The second polyether polyol includes one or more of N330, N310, N3050, N3500, 330N, and 403; (3) The third polyether polyol includes one or more of N210, N220, N230, N240, N260, 204, N330, N310, N3050, N3500, 330N, and 403; (4) The first polyether polyamine includes one or more of D2000, D400, and D230; (5) The second polyether polyamine includes one or more of D400, T5000, and T403; (6) The third polyether polyamine includes one or more of D2000, D400, D230, T5000, and T403; (7) The first polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate; (8) The second polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylmethylene diisocyanate (PDI), and L-lysine diisocyanate. (9) The third polyisocyanate includes one or more of the following: hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate; (10) The fourth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), L-lysine diisocyanate, hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate; (11) The fifth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (HMDI), terephthalic diisocyanate (PPDI), pentamethylene diisocyanate (PDI), and L-lysine diisocyanate; (12) The sixth polyisocyanate includes one or more of hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI) trimer, diphenylmethane diisocyanate (MDI) trimer, toluene diisocyanate (TDI) trimer, pentamethylene diisocyanate (PDI) trimer, triphenylmethane triisocyanate, and L-lysine triisocyanate.

23. The preparation method according to any one of claims 16-22, wherein, The solvent for the slurry includes one or more of N-methylpyrrolidone and tetrahydrofuran; and / or, The slurry has a viscosity of 100 mPa·s-1000 mPa·s at 25°C; and / or, The solid content of the slurry is 10%-60%.

24. A battery device comprising a plurality of battery cells as described in any one of claims 1-15 or a plurality of battery cells prepared by the preparation method described in any one of claims 16-23.

25. An electrical device comprising a battery cell according to any one of claims 1-15, or a battery cell prepared by any one of claims 16-23, or a battery device according to claim 24.

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