Diaphragm and battery

Abstract

The invention relates to the technical field of batteries, in particular to a diaphragm and a battery comprising the diaphragm. The diaphragm comprises a carrier layer and a first adhesive layer, the first adhesive layer is located on at least one side surface of the carrier layer, the first adhesive layer is of a porous structure, and the surface of the first adhesive layer comprises a synaptic structure; the carrier layer comprises a base material layer and a coating located on the surface of one side or two sides of the base material layer, the coating comprises a nitrogen-containing condensed ring organic matter, and the molecular structure of the nitrogen-containing condensed ring organic matter comprises a nitrogen-containing condensed ring. According to the diaphragm disclosed by the invention, a gap channel can be provided between the diaphragm and the pole piece, so that the liquid storage amount between the diaphragm and the pole piece is improved, the heat dissipation of an interface between the diaphragm and the pole piece in a thermal abuse test is improved, the side reaction of a positive electrode active material and an electrolyte can be reduced, and the dissolution of metal ions of the positive electrode active material is reduced or even inhibited; and the battery has relatively high high-temperature cycle performance and relatively high furnace temperature passing rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a separator and a battery comprising the same. BACKGROUND

[0002] In order to meet the performance requirements of long endurance and fast charging of electronic devices, lithium ion batteries are iteratively developed towards higher energy density and higher rate design. By using a negative electrode sheet containing silicon-based material, the energy density of the battery can be effectively improved. However, due to the huge volume change of silicon-based material during lithium extraction and insertion, the stress generated by this huge volume change will cause extrusion to the electrode sheet and the separator, resulting in a decrease in the gap between the separator and the electrode sheet, a decrease in the storage capacity of the electrolyte between the separator and the electrode sheet, and a significant deterioration of the high-temperature cycle performance. At the same time, the flow channel of gas is reduced in the thermal abuse test, and local heat is easily accumulated, and the oven temperature safety performance of the battery is significantly reduced.

[0003] Therefore, it is very important to invent a battery that can improve the liquid storage space and interface heat dissipation of the separator and the electrode sheet, and has higher high-temperature cycle performance and higher oven temperature passing rate. SUMMARY

[0004] It is found through research that the dissolved cobalt ions in the positive active material can damage the SEI film, increase the consumption of lithium ions and electrolyte, and cause the capacity attenuation of the battery to be large, especially at high temperature, which can further deteriorate the high-temperature cycle performance of the battery.

[0005] In order to improve the problems of insufficient liquid storage space and poor interface heat dissipation of the separator and the electrode sheet, which leads to a decrease in the oven temperature passing rate and the high-temperature cycle performance, and the damage of cobalt ions to the SEI film, which further deteriorates the high-temperature cycle performance of the battery, the present application provides a separator and a battery comprising the same. The separator of the present application not only can provide a gap channel between the separator and the electrode sheet, thereby improving the liquid storage capacity between the separator and the electrode sheet and improving the heat dissipation of the interface between the separator and the electrode sheet in the thermal abuse test, but also can reduce the side reaction of the positive active material and the electrolyte, and reduce or even inhibit the dissolution of metal ions (such as cobalt ions) of the positive active material, so that the battery has higher high-temperature cycle performance and higher oven temperature passing rate.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a separator, which comprises a carrier layer and a first adhesive layer, the first adhesive layer is located on at least one side surface of the carrier layer, the first adhesive layer has a porous structure, and the surface of the first adhesive layer comprises a synapse structure; the carrier layer comprises a substrate layer and a coating layer located on one side or both sides of the substrate layer, and the coating layer comprises a nitrogen-containing condensed ring organic matter, and the molecular structure of the nitrogen-containing condensed ring organic matter comprises a nitrogen-containing condensed ring.

[0007] The second aspect of the present application provides a battery, comprising a positive electrode sheet, a negative electrode sheet and the separator of the first aspect of the present application, the separator being located between the positive electrode sheet and the negative electrode sheet.

[0008] Compared with the prior art, the present application has at least the following advantages: In the separator of the present application, the synapse structure on the surface of the first adhesive layer can form a certain gap channel between the electrode sheet and the separator, thereby improving the electrolyte storage capacity and flowability of the interface between the electrode sheet and the separator, improving the high-temperature cycle performance of the battery, and also improving the interface heat dissipation between the separator and the electrode sheet in the thermal abuse test, reducing the risk of local heat accumulation, improving the oven temperature pass rate of the battery, and also absorbing and relieving the expansion stress of the silicon-based material when the silicon-based material expands, so that the separator maintains a good pore structure, improves the local liquid retention capacity of the separator, and still maintains a stable lithium ion transmission channel even if the separator is subjected to the extrusion effect of the expansion stress of the silicon-based material, further improving the high-temperature cycle performance of the battery. Moreover, the nitrogen-containing condensed ring organic matter in the coating can be complexed to the positive active surface to form a dense and strong physical barrier on the surface of the positive active material, reduce or even inhibit the side reaction of the positive active material with the electrolyte, reduce or even inhibit the dissolution of metal ions (such as cobalt ions) in the positive active material, and further improve the high-temperature cycle stability of the battery.

[0009] In summary, the separator of the present application cooperates the synapse structure on the surface of the first adhesive layer and the nitrogen-containing condensed ring organic matter in the coating, not only improves the liquid storage space and interface heat dissipation of the separator and the electrode sheet, and can absorb and relieve the expansion stress of the silicon-based material, so that the separator maintains a good pore structure, and the separator still maintains a stable lithium ion transmission channel even if it is subjected to the extrusion effect of the expansion stress of the silicon-based material, but also can form a dense and strong physical barrier on the surface of the positive active material, reduce or even inhibit the side reaction of the positive active material with the electrolyte, reduce or even inhibit the dissolution of metal ions (such as cobalt ions) in the positive active material, reduce or even avoid the damage of the dissolved metal ions (such as cobalt ions) in the positive active material to the SEI film, so that the battery has high high-temperature cycle performance and high oven temperature pass rate.

[0010] Other features and advantages of the present application will be described in detail in the following specific embodiments.

[0011] The endpoints of the ranges and any values disclosed in this document are not limited to the precise values recited as exactly that endpoint. Any values that fall within common interpretations of the endpoints should be considered as if explicitly written herein. For values that are presented as a range, the endpoints of the range are included as well as individual points within the range. For values that are presented as a maximum and a minimum, the maximum and minimum values are included as well as individual points in between the maximum and minimum values. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Fig. 1 shows a schematic diagram of the structure of the diaphragm of the present application.

[0013] Figure 2 Fig. 2 shows another schematic diagram of the structure of the diaphragm of the present application.

[0014] Figure 3 Fig. 3 shows a third schematic diagram of the structure of the diaphragm of the present application.

[0015] Figure 4 Fig. 4 shows a schematic diagram of the stripe coating in the first adhesive layer of the diaphragm of the present application.

[0016] Figure 5 Fig. 5 shows another schematic diagram of the stripe coating in the first adhesive layer of the diaphragm of the present application.

[0017] Figure 6 Fig. 6 shows a third schematic diagram of the stripe coating in the first adhesive layer of the diaphragm of the present application.

[0018] Figure 7 Fig. 7 shows a cross-sectional SEM image of the first adhesive layer of the diaphragm of the present application. DETAILED DESCRIPTION

[0019] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and explanatory and are not intended to limit the present application. In this text, the data range includes the end points unless otherwise specified.

[0020] It should be noted that the "first", "second" and the like numerical designations in the present application are only used to distinguish different substances or usage manners, and do not represent the difference in order.

[0021] The first aspect of the present application provides a diaphragm, wherein the diaphragm comprises a carrier layer and a first adhesive layer, the first adhesive layer is located on at least one side surface of the carrier layer, the first adhesive layer has a porous structure, and the surface of the first adhesive layer comprises a synaptic structure; the carrier layer comprises a substrate layer and a coating layer located on one side or both sides of the substrate layer, and the coating layer comprises a nitrogen-containing condensed ring organic matter, and the molecular structure of the nitrogen-containing condensed ring organic matter comprises a nitrogen-containing condensed ring.

[0022] The present application provides a diaphragm, which comprises a carrier layer, a first glue layer and a second glue layer, the first glue layer is located on one side surface of the carrier layer, the second glue layer is located on the other side surface of the carrier layer, the first glue layer and the second glue layer have a porous structure, and the surface of at least one of the first glue layer and the second glue layer comprises a synapse structure; the carrier layer comprises a substrate layer and a coating layer located on one side or both sides of the substrate layer, and the coating layer comprises a nitrogen-containing condensed ring organic matter, and the molecular structure of the nitrogen-containing condensed ring organic matter comprises a nitrogen-containing condensed ring.

[0023] In some specific embodiments, as shown in FIG. 1, the diaphragm 1 comprises a substrate layer 11, a coating layer 12, a first glue layer 131 and a second glue layer 132, the coating layer 12 is located on one side surface of the substrate layer 11, the first glue layer 131 is located on the surface of the coating layer 12, the second glue layer 132 is located on the other side surface of the substrate layer 11, and the surface of the first glue layer 131 comprises synapse structures 1311 and 1312. Figure 1 In some specific embodiments, as shown in FIG. 2, the diaphragm 1 comprises a substrate layer 11, a coating layer 12 and a first glue layer 131, the coating layer 12 is located on one side surface of the substrate layer 11, the first glue layer 131 is located on the surface of the coating layer 12 and the other side surface of the substrate layer 11, and the surface of the first glue layer 131 comprises synapse structures 1311 and 1312.

[0024] Figure 2 In some specific embodiments, as shown in FIG. 3, the diaphragm 1 comprises a substrate layer 11, a coating layer 12 and a first glue layer 131, the coating layer 12 is located on one side surface of the substrate layer 11, the first glue layer 131 is located on the surface of the coating layer 12 and the other side surface of the substrate layer 11, and the surface of the first glue layer 131 comprises synapse structures 1311 and 1312.

[0025] In some specific embodiments, as shown in FIG. 4, the diaphragm 1 comprises a substrate layer 11, a coating layer 12, a first glue layer 131 and a second glue layer 132, the coating layer 12 is located on both side surfaces of the substrate layer 11, the first glue layer 131 and the second glue layer 132 are respectively located on the surfaces of the coating layer 12 on both sides, and the surface of the first glue layer 131 comprises synapse structures 1311 and 1312. Figure 3 As shown in FIG. 5, the synapse structure in the blue circle.

[0026] Figure 7 As shown in FIG. 5, the synapse structure in the blue circle.

[0027] In the diaphragm of the present application, the coating layer comprises a nitrogen-containing condensed ring organic matter, the molecular structure of the nitrogen-containing condensed ring organic matter comprises a nitrogen-containing condensed ring, and at least one side surface of the carrier layer is provided with a first glue layer whose surface comprises a synapse structure.

[0028] ​​The surface of the first adhesive layer comprises a synapse structure, which can form a certain gap channel between the pole piece and the separator, on the one hand, can improve the storage capacity and flowability of the electrolyte between the separator and the pole piece, and improve the interface heat dissipation between the separator and the pole piece in the thermal abuse test, reduce the risk of local heat accumulation, improve the high-temperature cycle performance and oven temperature passing rate of the battery, on the other hand, the synapse structure can be compressed when the silicon-based material expands, and can absorb and relieve the expansion stress of the silicon-based material, so that the separator maintains a good pore structure, improves the local liquid retention capacity of the separator, and even under the extrusion effect of the expansion stress of the silicon-based material, the stable lithium ion transmission channel of the separator can be maintained, thereby further improving the high-temperature cycle performance of the battery.

[0029] Moreover, the nitrogen-containing condensed ring organic matter in the coating has a certain coordination ability, the lone pair electrons in the nitrogen-containing condensed ring organic matter can act as a ligand, and the nitrogen-containing condensed ring has a large planar conjugated pi bond system, which can be complexed to the surface of the positive active material, forming a dense and firm physical barrier on the surface of the active positive active material (for example, lithium cobaltate), reducing or even blocking the direct contact of the electrolyte with the high-activity positive active material, reducing or even inhibiting the oxidative decomposition of the electrolyte under high pressure and high temperature, reducing the interface impedance growth, and reducing or even inhibiting the dissolution of metal ions (such as cobalt ions) in the positive active material, reducing or even avoiding the damage of the metal ions (such as cobalt ions) dissolved from the positive active material to the SEI film, improving the stability of the positive active material and the negative active material under high temperature, and further improving the high-temperature cycle stability of the battery, that is, when the battery is subjected to thermal abuse test, due to the improvement of the high-temperature stability of the battery, the passing rate of the thermal abuse test is also significantly improved.

[0030] Therefore, in the separator of the present application, through the synergistic effect of the synapse structure on the surface of the first adhesive layer and the nitrogen-containing condensed ring organic matter in the coating, not only can the liquid storage space and the interface heat dissipation between the separator and the pole piece be improved, the expansion stress of the silicon-based particles can be absorbed and relieved, the high-temperature cycle performance and the oven temperature passing rate of the battery can be improved, but also a dense and firm physical barrier can be formed on the surface of the positive active material, the side reaction between the positive active material and the electrolyte can be reduced or even inhibited, the dissolution of metal ions (such as cobalt ions) can be reduced or even inhibited, the stability of the positive active material and the negative active material under high temperature can be improved, and the high-temperature cycle stability of the battery can be further improved, so that the battery has high high-temperature cycle performance and high oven temperature passing rate.

[0031] In this invention, by providing a gel layer including synaptic structures on at least one surface of the separator, and simultaneously adding a nitrogen-containing fused-ring organic compound to the coating, compared with the prior art, it is possible to improve the liquid storage space and interfacial heat dissipation between the separator and the electrode, enhance the stability of the positive and negative electrode active materials at high temperatures, and enable the battery to possess both high-temperature cycle performance and high furnace temperature throughput. To further improve the effect, one or more of the technical features can be further optimized.

[0032] In some instances, the first adhesive layer is located on one side surface of the carrier layer, and the diaphragm further includes a second adhesive layer located on the other side surface of the carrier layer, the second adhesive layer having a porous structure.

[0033] In some instances, the second adhesive layer includes a third polymer and optionally (“optionally” means that it may or may not be present) a fourth particle, the third polymer forming a porous structure of the second adhesive layer.

[0034] In some instances, the third polymer includes one or more of the following: fluoropolymers, polyacrylonitrile, acrylate polymers, polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl acetate, polyacrylamide, epoxy resin, ethylene-vinyl acetate copolymer, multi-component acrylic copolymer, lithium polystyrene sulfonate, polyethylene oxide, cyanoethyl polyvinyl alcohol, butadiene-acrylonitrile copolymer and its derivatives, aramid, phenolic resin, modified phenolic resin, polyimide, polyetherimide, and modified polyimide.

[0035] In some instances, the fourth particle comprises one or more of the following: boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, aluminum nitride, boron nitride, zirconium titanate, barium titanate, magnesium fluoride, melamine cyanurate, 1,3,5-triazine-2,4,6-triamine, melamine thiocyanate, uracil, cytosine, guanine, N,N'-di(β-naphthyl)-p-phenylenediamine, 4-amino-2,6-dihydroxypyrimidine, 2-mercaptobenzimidazole, and 2-mercaptobenzimidazole derivatives.

[0036] In some instances, the weight percentage of the fourth particle in the second adhesive layer is 0-70% (e.g., 0, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or any two of the above values). When the weight percentage of the fourth particle in the second adhesive layer is 0, it indicates that the fourth particle is not present.

[0037] In some instances, the second adhesive layer has a porous structure, and the second adhesive layer is continuously or discontinuously coated on the surface of the carrier layer. Discontinuous coating can be a striped coating.

[0038] In some instances, the first adhesive layer is located on one side surface of the carrier layer, and the diaphragm further includes a second adhesive layer located on the other side surface of the carrier layer, the second adhesive layer comprising third particles.

[0039] In some instances, the third particle includes a fourth polymer.

[0040] In some instances, the third particle can be an aggregated particle formed by the aggregation of small particles, or it can be a non-aggregated particle.

[0041] In some instances, the fourth polymer includes one or more of the following: fluoropolymers, polyacrylonitrile, acrylate polymers, polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl acetate, polyacrylamide, epoxy resin, ethylene-vinyl acetate copolymer, multi-component acrylic copolymer, lithium polystyrene sulfonate, polyethylene oxide, cyanoethyl polyvinyl alcohol, butadiene-acrylonitrile copolymer and its derivatives, aramid, phenolic resin, modified phenolic resin, polyimide, polyetherimide, and modified polyimide.

[0042] In some instances, the nitrogen-containing fused heterocycle is an unsubstituted or substituted nitrogen-containing fused heterocycle.

[0043] In some instances, the nitrogen-containing fused heterocycle includes one or more of the following: an unsubstituted or substituted benzimidazole ring, an unsubstituted or substituted imidazopyridine ring, an unsubstituted or substituted imidazopyrazine ring, an unsubstituted or substituted pyrrolopyrimidine ring, an unsubstituted or substituted quinoline ring, and an unsubstituted or substituted pteridine ring. More preferably, the nitrogen-containing fused heterocycle is an unsubstituted or substituted benzimidazole ring.

[0044] In some instances, the characteristic group is selected from one or more of the following: unsubstituted or substituted with substituent R, consisting of C1-C6 alkyl, C1-C6 alkoxy, hydroxyl, amino, carboxyl, cyano, halogen substituent, sulfonic acid, mercapto, and nitro groups, wherein the substituent R is selected from one or more of hydroxyl, amino, and carboxyl groups. It is understood that “C1-C6 alkyl” refers to an alkyl group containing 1 to 6 carbon atoms (e.g., 1, 2, 3, 4, 5, or 6), and “C1-C6 alkoxy” refers to an alkoxy group containing 1 to 6 carbon atoms (e.g., 1, 2, 3, 4, 5, or 6).

[0045] The C1-C6 alkyl group may be selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, 2,2-dimethylpropyl, 1-ethylpropyl, 1-methylbutyl, 2-methylbutyl, n-hexyl, isohexyl, 2-hexyl, and 3-hexyl.

[0046] The C1-C6 alkoxy group may be selected from one or more of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, tert-pentoxy, neopentoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, 1-methylbutoxy, 2-methylbutoxy, n-hexoxy, isohexoxy, 2-hexoxy, and 3-hexoxy.

[0047] In some instances, the substituent is selected from one or more of methyl, methoxy, ethoxy, hydroxy, amino, cyano, halogen substituent, sulfonic acid, carboxyl, and nitro groups.

[0048] The halogen substituent may be selected from one or more of F, Cl, Br and I.

[0049] In some instances, the nitrogen-containing fused-ring organic compound includes 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-5-methoxybenzimidazole, 2-mercapto-5-ethoxybenzimidazole, 2-mercapto-5-hydroxybenzimidazole, 2-mercapto-5-aminobenzimidazole, 2-mercapto-5-chlorobenzimidazole, 2-mercapto-5-sulfonic acid benzimidazole, 2-mercapto-5-carboxybenzimidazole, 2-mercapto-5-nitrobenzimidazole, 2 One or more of the following: lithium 2-thiolbenzimidazole, sodium 2-thiolbenzimidazole, potassium 2-thiolbenzimidazole, calcium 2-thiolbenzimidazole, magnesium 2-thiolbenzimidazole, aluminum 2-thiolbenzimidazole, ammonium 2-thiolbenzimidazole, imidazopyridine-6-methylamine, 7-chloro-imidazopyridine, 5-bromoimidazopyrazine, 2-amino-7H-pyrrolopyrimidine, 5-aminoquinoline, pteridine-2-amine, and pteridine-2-thiol.

[0050] In some instances, the nitrogen-containing fused-ring organic compound includes one or more of the following: 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-5-methoxybenzimidazole, 2-mercapto-5-ethoxybenzimidazole, 2-mercapto-5-hydroxybenzimidazole, 2-mercapto-5-aminobenzimidazole, 2-mercapto-5-chlorobenzimidazole, 2-mercapto-5-sulfonic acid benzimidazole, 2-mercapto-5-carboxybenzimidazole, 2-mercapto-5-nitrobenzimidazole, lithium salt of 2-thiolbenzimidazole, sodium salt of 2-thiolbenzimidazole, potassium salt of 2-thiolbenzimidazole, calcium salt of 2-thiolbenzimidazole, magnesium salt of 2-thiolbenzimidazole, aluminum salt of 2-thiolbenzimidazole, and ammonium salt of 2-thiolbenzimidazole. When the nitrogen-containing fused-ring organic compound is the aforementioned substance, the thiol group linked to the nitrogen-containing fused ring can not only neutralize trace amounts of acidic impurities such as HF in the electrolyte, breaking the vicious cycle of HF corroding the positive electrode active material and accelerating the dissolution of metal ions, reducing the corrosion of the positive electrode active material by acidic impurities, and further reducing or even inhibiting the dissolution of metal ions (such as cobalt ions) in the positive electrode active material, but also complex the metal ions (such as cobalt ions) dissolved in the positive electrode material, reducing or even preventing their migration to the negative electrode sheet and damaging the SEI film, reducing or even avoiding the vicious cycle of continuous repair and thickening of the SEI film, thereby reducing the consumption of lithium ions and electrolyte, improving the stability of the SEI film, and further improving the high-temperature cycle performance and furnace temperature pass rate of the battery.

[0051] In some instances, the coating comprises organic particles, which include nitrogen-containing fused-ring organic compounds.

[0052] In some instances, the Dv10 of the organic particles is 0.2 μm-0.9 μm (e.g., 0.2 μm, 0.23 μm, 0.25 μm, 0.28 μm, 0.3 μm, 0.33 μm, 0.35 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.9 μm, or within any two of the above values). Controlling the Dv10 of the organic particles within the above range is beneficial for the trace dissolution of the organic particles. Simultaneously, the smaller particle size of the organic particles results in a larger specific surface area, which increases the contact area between the organic particles and the electrolyte. This is beneficial for the nitrogen-containing fused-ring organic compounds in the organic particles to neutralize acidic impurities (e.g., HF) in the electrolyte, as well as for complexing cobalt ions (Co) dissolved from the positive electrode active material in the electrolyte. 2+The organic particles have a smaller specific surface area and less contact area with the electrolyte, which reduces their neutralization efficiency for acidic impurities (such as HF) in the electrolyte and their adsorption efficiency for cobalt ions dissolved from the positive electrode active material. This is detrimental to further improving the high-temperature cycle performance and furnace temperature throughput of the battery. When the Dv10 of the organic particles is lower than 0.2 μm, the organic particles are over-dissolved in the electrolyte, which is detrimental to the stability of the coating. In addition, the smaller particle size results in denser packing, reducing the porosity of the coating and compressing the space between the organic particles. This is not conducive to further improving the storage and wetting diffusion of the electrolyte, leading to localized capture of Co ions dissolved from the positive electrode active material. 2+ The reduced efficiency of ions is detrimental to further improving the high-temperature cycle performance and furnace temperature pass rate of the battery.

[0053] In some instances, the Dv10 of the organic particles is 0.2 μm to 0.35 μm.

[0054] In this invention, the Dv10 of the organic particles is the particle size corresponding to 10% of the cumulative particle size distribution in the volumetric particle size distribution of the organic particles. In this invention, the volumetric particle size distribution of the organic particles can be obtained by measuring and statistically processing SEM images of the coating surface using image analysis software (e.g., ImageJ, NanoMeasurer, Matlab, etc.). The Dv10 of the organic particles can also be obtained by testing with a laser particle size analyzer. For example, before preparing the diaphragm, the Dv10 of the organic particles can be measured using a laser particle size analyzer within 5 minutes after thorough stirring.

[0055] In some instances, when the surface of the coating is observed at 20K magnification, the number of organic particles with a diameter less than 0.1 μm is less than or equal to 200 (e.g., 200, 190, 180, 170, 160, 150, 140, 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10) within an area of ​​optionally 5 μm × 5 μm. Studies have found that a large number of small-diameter organic particles can lead to uneven dispersion, resulting in excessively high local packing density and excessively small local pores. This is detrimental to lithium-ion transport and reduces the uniformity of lithium-ion transport channels within the coating. Controlling the number of organic particles smaller than 0.1 μm within an optional 5 μm × 5 μm area within the specified range helps improve the uniformity of organic particle dispersion. Simultaneously, it prevents excessively small local pores in the coating, improving the uniformity of the separator's pore structure. During battery charging and discharging, the lithium-ion flow becomes more uniform. Furthermore, a uniform coating provides an effectively homogenized ion transport channel during charging and discharging, reducing uneven local current density distribution, lowering interfacial impedance, inhibiting lithium dendrite growth, improving battery safety and stability, and reducing the risk of thermal runaway. If the number of organic particles with a diameter less than 0.1 μm is greater than 200 within an area of ​​5 μm × 5 μm, the risk of uneven dispersion of organic particles increases. Due to the uneven dispersion of organic particles, during the charging and discharging process of the battery, lithium ions will preferentially pass through areas with low resistance (thin coating or large pores), resulting in excessively high local current density, which will drastically increase the risk of lithium dendrites formed by the precipitation of metallic lithium.

[0056] In some instances, when the surface of the coating was observed at 1K magnification, the number of organic particles larger than 7 μm in diameter within an area of ​​optionally 100 μm × 80 μm was less than or equal to 50 (e.g., 0, 1, 3, 5, 10, 15, 20, 25, 50). Studies have found that a large number of large-diameter organic particles can lead to uneven dispersion, resulting in localized loose packing and excessively large pores. This reduces the uniformity of lithium-ion transport channels within the coating. Controlling the number of particles within the aforementioned range helps improve the uniformity of organic particle dispersion.

[0057] In some specific embodiments, in some examples, when the surface of the coating is observed at a 20K magnification, the number of organic particles with a diameter less than 0.1 μm is less than or equal to 200 within an area of ​​optionally 5 μm × 5 μm, and when the surface of the coating is observed at a 1K magnification, the number of organic particles with a diameter greater than 7 μm is less than or equal to 50 within an area of ​​optionally 100 μm × 80 μm. Controlling the organic particles in the coating to meet the above ranges can further improve the dispersion uniformity of the organic particles, thereby further reducing the risk of thermal runaway in the battery and improving battery safety performance.

[0058] In some instances, the organic particles in the coating constitute 70%-98% by weight (e.g., 70%, 73%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 93%, 95%, 98%, or within any two of the above values).

[0059] In some instances, the organic particles in the coating constitute 90%-98% by weight.

[0060] In some instances, the coating also includes filler particles.

[0061] In some instances, the filler particles are composed of one or more of the following: boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, aluminum nitride, boron nitride, zirconium titanate, barium titanate, magnesium fluoride, melamine cyanurate, 1,3,5-triazine-2,4,6-triamine, melamine thiocyanate, uracil, cytosine, guanine, N,N'-di(β-naphthyl)-p-phenylenediamine, 4-amino-2,6-dihydroxypyrimidine, and phenolic resin.

[0062] In some instances, the filler particles in the coating comprise 1%-26% by weight (e.g., 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 26%, or any combination of the above values).

[0063] In some instances, the coating also includes a first adhesive.

[0064] In some instances, the first adhesive comprises one or more of polyvinyl alcohol, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, sodium carboxymethyl cellulose, polyvinylpyrrolidone, styrene-acrylic latex, polyacrylonitrile, acrylate polymers, polyvinyl acetate, acrylic polymers, polyurethane, fluoropolymers, or copolymers derived from the above polymers.

[0065] In this invention, the acrylic polymers include one or more of polymethyl acrylate, polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, and polyethyl methacrylate.

[0066] In some instances, the weight percentage of the first adhesive in the coating is 1%-15% (e.g., 1%, 3%, 5%, 8%, 10%, 13%, 15%, or within any two of the above values).

[0067] In some instances, the coating does not include filler particles, and the organic particles in the coating constitute 90%-98% by weight (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or any two of the above values), and the first binder in the coating constitutes 2%-10% by weight (e.g., 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of the above values).

[0068] In some examples, the coating thickness is 0.2 μm-5 μm (e.g., 0.2 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or within any two of the above values). Controlling the coating thickness within the above range can further enhance the complexation of metal ions (such as cobalt ions) dissolved from the positive electrode active material in the electrolyte, including the organic particles, while neutralizing trace amounts of acidic impurities such as HF in the electrolyte. When the coating thickness is less than 0.2 μm, the coating thickness is too small, resulting in a smaller amount of complexed metal ions (such as cobalt ions) and a smaller amount of neutralized acidic impurities such as HF, which is not conducive to further improving the high cycle performance and furnace temperature pass rate of the battery. When the coating thickness is greater than 5 μm, the coating thickness is too thick, which will affect the energy density of the battery.

[0069] In some instances, the coating thickness is 0.5 μm to 3 μm.

[0070] In this invention, the thickness of the coating is the average thickness of the coating. The thickness of the coating can be tested by the following method: 10 test sites are selected at equal intervals along the length of the diaphragm, and the thickness of the coating at each of the 10 test sites is measured. The average value is taken as the test result of the coating thickness. "Equal intervals" means that the distance between two adjacent test sites is equal.

[0071] In some instances, the synaptic structure protrudes partially or entirely from the surface of the first adhesive layer. It is understood that saying the synaptic structure protrudes partially or entirely from the surface of the first adhesive layer means that a single synaptic structure may be partially embedded in the first adhesive layer and partially located on the surface of the first adhesive layer (e.g., Figure 1 , Figure 2 and Figure 3 (e.g., 1311), or a single synaptic structure located entirely on the surface of the first adhesive layer (e.g., ...). Figure 1 , Figure 2 and Figure 3(1312 in the text). All synaptic structures located on the surface of the first adhesive layer may be the same or different. For example, all synaptic structures on the surface of the first adhesive layer may protrude entirely from the surface of the first adhesive layer, all may protrude partially from the surface of the first adhesive layer, or some synaptic structures may protrude entirely from the surface of the first adhesive layer and some synaptic structures may protrude partially from the surface of the first adhesive layer. For ease of understanding, in Figure 1 , Figure 2 and Figure 3 In the image, the outline of the portion of the synaptic structure 1311 embedded in the first adhesive layer, which is located on the surface of the first adhesive layer, is drawn with a red dashed line.

[0072] In some examples, the average height of the synaptic structure is 0.1 μm-30 μm (e.g., 0.1 μm, 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, 20 μm, 23 μm, 25 μm, 28 μm, 30 μm, or within any two of the above values). Controlling the average height of the synaptic structure within the above range can, on the one hand, create sufficient liquid storage space and heat dissipation channels between the separator and the electrode, further improving the high-temperature cycle performance and furnace temperature throughput of the battery. On the other hand, it can solve the problem of pore structure collapse of the separator under stress due to the expansion of the negative electrode active material, while ensuring that the separator can still maintain a good pore structure when the negative electrode active material expands, so that the battery can have good dynamic performance, thereby achieving high rate performance and good cycle performance. When the average height of the synaptic structure is higher than 30 μm, the height of the synaptic structure is too high, which increases the lithium-ion transport path, affects the rapid migration of lithium ions, and affects the rate performance of the battery.

[0073] In some instances, the average height of the synaptic structure is 2 μm-10 μm.

[0074] In this invention, the average height of the synaptic structure refers to the average height of the synaptic structure, such as... Figure 1 As shown, the height H of a single synaptic structure 0 This refers to the height of the synaptic structure protruding from the surface of the first adhesive layer, i.e., the size of the portion of the synaptic structure on the surface of the first adhesive layer. The average height of the synaptic structure can be tested using the following method: In the SEM image of the diaphragm cross-section obtained by scanning with a scanning electron microscope, take any 100μm × 100μm area on the surface of the first adhesive layer, and measure the height of any 10 synaptic structures in this area. The average height of any 10 synaptic structures is the average height. Repeat the above operation 5 times, and take the average of the 5 test results as the average height of the synaptic structure protruding from the surface of the first adhesive layer. If the number of synaptic structures is less than 10, change the location and continue measuring until there are 10.

[0075] In some instances, the number of synaptic structures on the surface of the first adhesive layer is greater than 10 (e.g., 100, 500, 1000, 3000, 5000, 8000, 10000, 13000, 15000, 18000, 2000) within an area of ​​500 μm × 500 μm, and the number of synaptic structures is less than 700 (e.g., 699, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 50, 10) within an area of ​​100 μm × 100 μm. Research has shown that controlling the number of synaptic structures within a larger area can maintain the stability of the separator structure while minimizing the impact on lithium-ion transport paths caused by increased distance between the separator and the electrode, thereby reducing lithium-ion transport obstacles caused by structural changes. Controlling the number of synaptic structures within a smaller area can alleviate the problem of excessively large local gaps, preventing insufficient lithium intercalation in the negative electrode due to insufficient electrolyte in the later stages of battery cycling. By controlling the number of synaptic structures on the surface of the first adhesive layer within the above-mentioned range, the stress buffering characteristics of the separator can be further improved. When the battery is charged and discharged, as the negative electrode active material expands, the separator can absorb and alleviate the stress generated by the expansion of the negative electrode active material through compression, further reducing the risk of separator pore structure collapse, providing a smooth channel for lithium-ion transport, and taking into account battery dynamics performance, thus enabling the battery to have better rate performance and cycle performance.

[0076] In some instances, the synaptic structure includes a first particle, which comprises a first polymer.

[0077] In some instances, the first particle can be an aggregated particle formed by the aggregation of small particles, or it can be a non-aggregated particle.

[0078] In some instances, the first polymer includes one or more of the following: fluoropolymers, polyacrylonitrile, acrylate polymers, polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl acetate, polyacrylamide, epoxy resin, ethylene-vinyl acetate copolymer, multi-component acrylic copolymer, lithium polystyrene sulfonate, polyethylene oxide, cyanoethyl polyvinyl alcohol, butadiene-acrylonitrile copolymer and its derivatives, aramid, phenolic resin, modified phenolic resin, polyimide, polyetherimide, and modified polyimide.

[0079] In this invention, the acrylate polymers include one or more of the following: polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymer, acrylate monomer-ethylene copolymer, acrylate monomer-acrylonitrile-ethylene copolymer, styrene-acrylate monomer-acrylonitrile copolymer, ethylhexyl acrylate-methyl methacrylate copolymer, butyl acrylate-methyl methacrylate copolymer, methyl acrylate-N,N-dimethylacrylamide copolymer, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymer, ethyl acrylate-N,N-diethylacrylamide copolymer, and ethyl acrylate-2-(diethylamino)ethyl acrylate.

[0080] In this invention, the acrylate monomers include one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate.

[0081] In this invention, the fluoropolymer includes one or more of the following: polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trichloroethylene, polyvinylidene fluoride-chlorotrifluoroethylene, acrylic acid-vinylidene fluoride copolymer, and acrylonitrile-vinylidene fluoride copolymer.

[0082] In some instances, the first adhesive layer includes a second polymer and optionally (“optionally” means that it may or may not be present) second particles, the second polymer forming a porous structure of the first adhesive layer.

[0083] In some instances, the second polymer includes one or more of the following: fluoropolymers, polyacrylonitrile, acrylate polymers, polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl acetate, polyacrylamide, epoxy resin, ethylene-vinyl acetate copolymer, multi-component acrylic copolymer, lithium polystyrene sulfonate, polyethylene oxide, cyanoethyl polyvinyl alcohol, butadiene-acrylonitrile copolymer and its derivatives, aramid, phenolic resin, modified phenolic resin, polyimide, polyetherimide, and modified polyimide.

[0084] In some instances, the first polymer, the second polymer, the third polymer, and the fourth polymer may be the same or different.

[0085] In some instances, the second particle comprises one or more of the following: boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, aluminum nitride, boron nitride, zirconium titanate, barium titanate, magnesium fluoride, melamine cyanurate, 1,3,5-triazine-2,4,6-triamine, melamine thiocyanate, uracil, cytosine, guanine, N,N'-di(β-naphthyl)-p-phenylenediamine, 4-amino-2,6-dihydroxypyrimidine, 2-mercaptobenzimidazole, and 2-mercaptobenzimidazole derivatives.

[0086] In some instances, the second and fourth particles may have the same or different compositions.

[0087] In some instances, the 2-mercaptobenzimidazole derivatives include one or more of the following: 2-mercapto-5-methylbenzimidazole, 2-mercapto-5-methoxybenzimidazole, 2-mercapto-5-ethoxybenzimidazole, 2-mercapto-5-hydroxybenzimidazole, 2-mercapto-5-aminobenzimidazole, 2-mercapto-5-chlorobenzimidazole, 2-mercapto-5-sulfonic acid benzimidazole, 2-mercapto-5-carboxybenzimidazole, 2-mercapto-5-nitrobenzimidazole, lithium salt of 2-thiolbenzimidazole, sodium salt of 2-thiolbenzimidazole, potassium salt of 2-thiolbenzimidazole, calcium salt of 2-thiolbenzimidazole, magnesium salt of 2-thiolbenzimidazole, aluminum salt of 2-thiolbenzimidazole, and ammonium salt of 2-thiolbenzimidazole.

[0088] In some instances, the weight percentage of the second particles in the first adhesive layer is 0-70% (e.g., 0, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or any two of the above values). When the weight percentage of the second particles in the first adhesive layer is 0, it indicates that the second particles are not present.

[0089] In some instances, the first adhesive layer is applied continuously or discontinuously to the surface of the carrier layer. Discontinuous application can be striped application (e.g.,...). Figure 4 , Figure 5 and Figure 6 (As shown).

[0090] In some instances, the first adhesive layer includes a synaptic structure and comprises a first particle and a second polymer; the second adhesive layer does not include a synaptic structure, is a porous structure, and comprises a third polymer.

[0091] In some instances, the first adhesive layer includes a synaptic structure and comprises a first particle and a second polymer; the second adhesive layer does not include a synaptic structure, is a porous structure, and comprises a third polymer and a fourth particle.

[0092] In some instances, the first adhesive layer includes a synaptic structure, comprising a first particle, a second polymer, and a second particle; the second adhesive layer does not include a synaptic structure, is porous, and comprises a third polymer.

[0093] In some instances, the first adhesive layer includes a synaptic structure, comprising a first particle, a second polymer, and a second particle; the second adhesive layer does not include a synaptic structure, is a porous structure, and comprises a third polymer and a fourth particle.

[0094] In some instances, the first adhesive layer includes synaptic structures, and the first adhesive layer includes first particles and a second polymer; the second adhesive layer includes third particles.

[0095] In some instances, the first adhesive layer includes synaptic structures, and the first adhesive layer includes first particles, a second polymer, and a second particle; the second adhesive layer includes a third particle.

[0096] In some instances, the first adhesive layer includes a synaptic structure and comprises a first particle and a second polymer; the second adhesive layer has a porous structure and comprises a third polymer.

[0097] In some instances, when the first adhesive layer is located only on one side of the carrier layer, the first adhesive layer is intended to face the positive electrode.

[0098] In some instances, the thickness of the first adhesive layer is 0.5 μm to 5 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or within any two of the above values. The thickness of the first adhesive layer does not include the height of the portion of the synaptic structure protruding from the surface of the first adhesive layer, such as... Figure 1 The value of D in the figure represents the thickness of the first adhesive layer.

[0099] In this invention, the synaptic structure on the surface of the first adhesive layer can be achieved in the following ways.

[0100] In some instances, a first particle, a second polymer, and optionally a second particle are dispersed in an organic solvent to form a first adhesive slurry. This first adhesive slurry is then coated onto the surface of a carrier layer to form a first adhesive layer with a synaptic structure. It is understood that the synaptic structure can be formed from first particles that are not dissolved in the organic solvent. This undissolved state can be due to the first particle itself being insoluble in the organic solvent, or it can be due to first particles that have not completely dissolved before the formation of the first adhesive layer. This can be achieved by controlling the size of the first particles, the order of addition, and the dispersion process (e.g., dispersion time).

[0101] In some instances, the organic solvent includes at least one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), and acetone.

[0102] In other examples, a second polymer and optionally second particles are dispersed in a first solvent to form a first adhesive slurry A. The first adhesive slurry A is then coated onto the surface of a carrier layer to form a porous adhesive layer A. The first particles are dispersed in a second solvent to form a first adhesive slurry B. The first adhesive slurry B is then coated onto the surface of the porous adhesive layer A to form a first adhesive layer. The coating method for the first adhesive slurry A can be continuous or stripe coating. The coating method for the adhesive slurry B can be gravure coating, dot matrix coating, or spray coating. The distribution of the synaptic structures in the adhesive layer can be regular or irregular, and can be achieved through coating roller design or spray coating processes.

[0103] In some instances, the first solvent includes at least one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), and acetone.

[0104] In some instances, the second solvent includes at least one of water, N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), and acetone.

[0105] In some instances, the thickness of the substrate layer is 3μm-16μm (e.g., 3.5μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm or within any two of the above values).

[0106] In some instances, the thickness of the substrate layer is 4 μm-9 μm.

[0107] In some instances, the porosity of the substrate layer is 30%-75% (e.g., 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or within any two of the above values).

[0108] In some instances, the porosity of the substrate layer is 38%-55%.

[0109] In this invention, the porosity of the substrate layer is measured by the following method: the battery is disassembled, the separator is removed, and the coating on the surface of the substrate layer is removed. When the residual amount of coating on the surface of the substrate layer is less than 5%, it is considered as obtaining a test sample of the substrate layer. Alternatively, the original substrate layer without coating is used as a test sample. The test sample is tested in accordance with the standard "GB / T-36363-2018 Polyolefin Separator for Lithium-ion Batteries" to obtain the porosity of the substrate layer.

[0110] In some instances, the average pore size of the substrate layer is 30nm-55nm (e.g., 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, or within any two of the above values).

[0111] In some instances, the substrate layer comprises one or more of the following polymer derivatives: polyolefin, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyethylene terephthalate, polybutylene terephthalate, poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), or poly(m-phenylene isophthalamide).

[0112] A second aspect of the present invention provides a battery comprising a positive electrode, a negative electrode, and a separator as described in the first aspect of the present invention, wherein the separator is located between the positive electrode and the negative electrode.

[0113] In some instances, the positive electrode sheet includes a positive current collector and a positive active layer located on one or both sides of the surface of the positive current collector. The positive active layer includes positive active particles. The battery satisfies the following relationship: 0.2 < d / H < 10 (e.g., 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9.5, 9.9, or within any two of the above values), where d is the Dv50 of the positive active particles in μm, and H is the average height of the synaptic structure in μm.

[0114] When d / H ≤ 0.2, the particle size of the positive electrode active particles is small, the particle packing is dense, the gaps between the positive electrode active particles are small, the surface of the positive electrode active layer is relatively flat, and the liquid retention capacity of the positive electrode active layer is weak. At this time, if a larger synaptic structure is selected, the gap between the separator and the positive electrode sheet will be too large, the diffusion path of lithium ions will be long, and as the battery charge and discharge process proceeds, the remaining electrolyte will not be consumed in time, which will easily lead to an increase in local interfacial impedance, and lithium ions will not be able to insert and extract in time, thus deteriorating the rate performance of the battery. When d / H ≥ 10, the particle size of the positive electrode active particles is large, and the particle packing is relatively loose. At this time, if a smaller synaptic structure is selected, the synaptic structure is easy to embed between the positive electrode active particles, resulting in a small gap between the separator and the positive electrode sheet. This is not conducive to absorbing and relieving the expansion stress of silicon-based particles. As the battery charge and discharge process proceeds, the separator at the arc is easily squeezed, which will lead to local lithium ion transport obstruction and liquid shortage, and increase the interfacial impedance, which is not conducive to improving the lithium plating at the arc of the battery. Therefore, controlling the battery to satisfy the above relationship can further improve both the arc-shaped lithium plating of the battery and the rate performance of the battery.

[0115] In some instances, the Dv50 of the positive electrode active particles is 2μm-20μm (e.g., 2μm, 5μm, 7μm, 10μm, 12μm, 15μm, 17μm, 20μm or within any two of the above values).

[0116] In this invention, the Dv50 of the positive electrode active particles is the particle size corresponding to 50% of the cumulative particle size distribution in the volumetric particle size distribution of the positive electrode active particles. The Dv50 of the positive electrode active particles in this invention can be obtained by testing with a laser particle size analyzer, or by measurement and statistical processing using SEM combined with graphical analysis software (e.g., ImageJ, NanoMeasurer, Matlab, etc.).

[0117] In some instances, the positive electrode active particles are composed of one or more of lithium nickel oxide, lithium titanate, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide.

[0118] In some instances, the average height H of the synaptic structure is 0.1 μm to 30 μm (e.g., 0.1 μm, 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, 20 μm, 23 μm, 25 μm, 28 μm, 30 μm or within any two of the above values).

[0119] In some instances, the average height H of the synaptic structure is 2 μm-10 μm.

[0120] According to some specific implementation methods, d is 2-20, H is 0.1-30, and the battery satisfies the following relationship: 0.2 < d / H < 10.

[0121] According to some specific implementation methods, d is 2-20, H is 2-10, and the battery satisfies the following relationship: 0.2 < d / H < 10.

[0122] In some instances, the negative electrode sheet includes a negative current collector and a negative active layer located on one or both sides of the surface of the negative current collector.

[0123] In some instances, the negative electrode active layer comprises a silicon-based material, which includes one or more of elemental silicon particles, silicon oxide particles, silicon-carbon composite particles, silicon-nitrogen composite particles, and silicon alloy particles.

[0124] In some instances, the average particle size of the silicon-carbon composite particles is 5 μm to 12 μm (e.g., 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm or within any two of the above values).

[0125] In this invention, the average particle size of the silicon-carbon particles can be obtained by the following method: On a scanned image of the surface of the negative electrode active layer, draw the smallest square or rectangle that completely surrounds one silicon-carbon particle, i.e., draw a square or rectangle whose edge of the silicon-carbon particle is connected to the four sides of the square or rectangle. The length of one side of the square or the length of the long side of the rectangle is the particle size of the silicon-carbon particle. The average particle size is the number of particle sizes of any 100 silicon-carbon particles on the surface of the negative electrode active layer. Repeat the above operation 5 times and take the average value as the average particle size of the silicon-carbon particles. It should be noted that when 100 silicon-carbon particles can be observed in the captured image, the average particle size of any 100 silicon-carbon particles in the image is taken as the average particle size of the silicon-carbon particles. When no 100 silicon-carbon particles are observed in the image, take multiple images and take the average particle size of the total number of 100 silicon-carbon particles as the average particle size. The average particle size of the silicon-carbon particles can also be obtained by testing with a laser particle size analyzer. For example, before preparing the negative electrode, the average particle size of the silicon-carbon particles can be obtained by measuring the silicon-carbon particles with a laser particle size analyzer.

[0126] In some instances, the negative electrode active layer further includes a carbon-based material, which includes one or more of natural graphite and artificial graphite.

[0127] In some instances, the negative electrode active layer comprises a negative electrode active material, which includes silicon-based materials and optionally ("optionally" means that it may or may not be present) carbon-based materials.

[0128] In some instances, the carbon-based materials include synthetic graphite and natural graphite.

[0129] In some instances, the negative electrode active material is a silicon-based material.

[0130] In some instances, based on the total weight of the negative electrode active layer, the weight percentage of silicon-based material can be in the range of 0%-99% (e.g., 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or within any two of the above values), and the weight percentage of carbon-based material can be in the range of 99%-0% (e.g., 99%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 1%, 0%, or within any two of the above values).

[0131] In some instances, the negative electrode active material layer also includes a negative electrode conductive agent and a negative electrode binder.

[0132] In some instances, the negative electrode conductive agent includes one or more of conductive carbon black, graphene, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, and carbon nanotubes.

[0133] In some instances, the negative electrode binder includes one or more of polyurethane, polyacrylic acid, acrylic-acrylonitrile copolymer, acrylate polymers, sodium carboxymethyl cellulose, styrene-butadiene latex, and fluoropolymers.

[0134] In some instances, based on the total weight of the negative electrode active layer, the weight percentage of the negative electrode active material is 80%-99% (e.g., 80%, 83%, 85%, 88%, 90%, 93%, 95%, 97%, 99%, or within any two of the above values), the weight percentage of the negative electrode conductive agent is 0.5%-10% (e.g., 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or within any two of the above values), and the weight percentage of the negative electrode binder is 0.5%-10% (e.g., 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or within any two of the above values).

[0135] In some instances, the battery also includes an electrolyte.

[0136] In some instances, the electrolyte comprises a lithium salt, a solvent, and additives. The solvent includes polar solvents.

[0137] In some instances, the electrolyte includes a polar solvent selected from at least one of 2,2-difluoroethyl acetate, ethyl 2,2-difluoroacetate, propyl propionate, ethyl propionate, diethyl carbonate, propylene carbonate, and ethylene carbonate.

[0138] In some instances, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, lithium tetrafluoroborate, lithium di(oxalate)borate, lithium di(fluorooxalate)borate, and lithium di(fluorobis(oxalate))phosphate.

[0139] In some instances, the additives can be selected based on battery performance requirements and in conjunction with industry-standard technologies.

[0140] In some instances, the solvent may also include organic solvents other than the aforementioned polar solvents.

[0141] In some instances, the lithium salt accounts for 5%-35% of the total weight of the electrolyte (e.g., 5%, 10%, 15%, 20%, 25%, 30%, or 35%), the solvent accounts for 30%-80% of the total weight of the electrolyte (e.g., 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%), and the additives account for 3%-35% of the total weight of the electrolyte (e.g., 3%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%).

[0142] In some instances, the battery is a lithium-ion rechargeable battery.

[0143] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0144] The following examples illustrate the separator and battery of the present invention.

[0145] Example 1 (1) Diaphragm 94 parts by weight of organic particles (2-mercaptobenzimidazole, with a Dv10 of 0.25 μm) and 6 parts by weight of the first binder (polyacrylic acid) were mixed in water and stirred thoroughly to obtain a coating slurry with a solid content of 25%. The coating slurry was applied to one side of a substrate layer (polyethylene) with a thickness of 5 μm and a porosity of 40% using a gravure roller. After drying in a multi-section oven at 60°C, a coating with a thickness of 1.5 μm was formed.

[0146] The first granule (PMMA) and DMAC are mixed and thoroughly stirred until dissolved. Then, the second granule (alumina) and the second polymer (PVDF) are added and stirred until uniformly dispersed to obtain a first adhesive slurry with a solid content of 8%. The first adhesive slurry is then coated onto the surface of the coating layer using a gravure roller. The mass ratio of the second polymer, the second granule, and the first granule is 4:5:1. The first granule (PMMA) is formed by copolymerization of styrene, acrylonitrile, and acrylate monomers, with a molar ratio of styrene:acrylonitrile:acrylate of 4:3:3. The thickness of the first adhesive layer is 1 μm, and the average synaptic height H is 2.7 μm. On the surface of the first adhesive layer, optionally within an area of ​​500 μm × 500 μm, the number of synaptic structures is 4922; optionally within an area of ​​100 μm × 100 μm, the number of synaptic structures is 226. The first adhesive layer is continuously coated.

[0147] The third polymer (PVDF) and DMAC are mixed and stirred until dissolved. Then, the fourth particle (alumina) is added and stirred until evenly dispersed to obtain a second adhesive slurry with a solid content of 8%. The second adhesive slurry is coated onto the other side of the substrate layer using a gravure roller. The mass ratio of the third polymer to the fourth particle is 1:1, and the second adhesive layer is continuously coated.

[0148] The diaphragm coated with adhesive slurry on both sides is pore-forming by extracting organic solvent in a water bath, and then dried in a multi-section oven at 60°C to form a diaphragm with a second adhesive layer thickness of 1μm.

[0149] (2) Preparation of positive electrode sheet Lithium cobalt oxide (Dv50 of 15 μm), polyvinylidene fluoride (PVDF 500) binder, and conductive material (Super P: carbon nanotubes = 2:1) were mixed in N-methylpyrrolidone (NMP) solvent at a weight ratio of 98:1:1 and continuously stirred under the action of a stirrer to form a homogeneous and fluid positive electrode slurry. Subsequently, the positive electrode slurry was coated on both sides of an aluminum foil with a thickness of 10 μm and dried in a vacuum oven at 120°C for 6 hours. Then, it was rolled and slit to obtain the positive electrode sheet.

[0150] (3) Preparation of negative electrode sheet Graphite, silicon carbide (Dv50=7μm), conductive material (carbon black: carbon nanotubes = 1:1), sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber were mixed in an aqueous solvent at a weight ratio of 89:8:1:0.5:1.5 and continuously stirred under the action of a stirrer to form a homogeneous and fluid negative electrode slurry. Subsequently, the slurry was coated on both sides of a 10μm thick current collector copper foil and dried in a vacuum oven at 120℃ for 6 hours. Then, it was rolled and slit to obtain the negative electrode sheet.

[0151] (4) Preparation of electrolyte In an argon-filled glove box (moisture content <1 ppm, oxygen content <1 ppm), ethylene carbonate, propylene carbonate, propyl propionate, and ethyl propionate solvents were mixed in a volume ratio of 15:15:50:20 to form a homogeneous solvent. Then, 16 wt% LiPF6, 3 wt% 1,3,6-hexanetrionitrile, and 20 wt% fluoroethylene carbonate (based on the total mass of the electrolyte) were slowly added and stirred until homogeneous to obtain the electrolyte.

[0152] (5) Preparation of lithium-ion batteries The positive electrode sheet obtained in step (2), the separator obtained in step (1), and the negative electrode sheet obtained in step (3) are wound together to form a bare battery cell. Then, the bare battery cell is placed in an aluminum-plastic film, and the electrolyte obtained in step (4) is injected into the dried bare battery cell. After vacuum sealing, room temperature standing, and high temperature formation, a lithium-ion battery is obtained. The positive electrode sheet corresponds to the side of the separator with the first adhesive layer, and the negative electrode sheet corresponds to the side of the separator with the second adhesive layer.

[0153] Example 2 group Example 2a The procedure is carried out in accordance with Example 1, except that the positive electrode plate and the side of the separator with the second adhesive layer are opposite to each other, and the negative electrode plate and the side of the separator with the first adhesive layer are opposite to each other.

[0154] Example 2b The procedure was carried out in accordance with Example 1, except that the first adhesive layer did not include the second particle, and the second adhesive layer did not include the fourth particle.

[0155] Example 2c The procedure was carried out in accordance with Example 1, except that the first particle (PMMA) and DMAC were mixed and thoroughly stirred to dissolve. Then, the second particle (alumina) and the second polymer (PVDF) were added and stirred to disperse evenly, resulting in a first adhesive slurry with a solid content of 8%. The first adhesive slurry was then coated onto the surface of the coating layer and the other side of the substrate layer using a gravure roller. The mass ratio of the second polymer, the second particle, and the first particle was 4:5:1. The average synaptic height H was 2.2 μm. On the surface of the first adhesive layer, optionally within an area of ​​500 μm × 500 μm, the number of synaptic structures was 4561, and optionally within an area of ​​100 μm × 100 μm, the number of synaptic structures was 151. The first adhesive layer was continuously coated.

[0156] Example 2d The procedure was carried out in accordance with Example 1, except that both the first and second adhesive layers were coated with stripes. On the surface of the first adhesive layer, optionally within an area of ​​500 μm × 500 μm, the number of synaptic structures was 1445, and optionally within an area of ​​100 μm × 100 μm, the number of synaptic structures was 78.

[0157] Example 2e The procedure was carried out in accordance with Example 1, except that the third particle (PMMA) was dispersed in water and stirred until uniformly dispersed to obtain a second adhesive slurry with a solid content of 8%. The second adhesive slurry was then coated onto the other side of the substrate layer using a gravure roller. The third particle was a dispersed particle with an average particle size of 0.8 μm.

[0158] Example 3 Group This set of examples illustrates the effects of changes in the Dv10 of organic particles.

[0159] This embodiment group is based on Example 1, except that the Dv10 of the organic particles is changed, as detailed in Table 1-1.

[0160] Example 4 group This embodiment group is based on Embodiment 1, except that one or more of the following are changed: the number of organic particles with a diameter less than 0.1 μm in an area of ​​5 μm × 5 μm, and the number of organic particles with a diameter greater than 7 μm in an area of ​​80 μm × 100 μm, as detailed in Table 1-1.

[0161] Table 1-1 Example 5 group Example 5a The process was carried out in accordance with Example 1, except that the weight percentage of organic particles in the coating was 90%, the weight percentage of the first binder in the coating was 10%, and the thickness of the coating was 0.5 μm.

[0162] Example 5b The process was carried out in accordance with Example 1, except that the weight percentage of organic particles in the coating was 98%, the weight percentage of the first binder in the coating was 2%, and the thickness of the coating was 3 μm.

[0163] Example 5c The process was carried out in accordance with Example 1, except that filler particles were added to the coating. The filler particles were composed of phenolic resin. Based on the total weight of the coating, the weight percentage of organic particles was 93%, the weight percentage of filler particles was 1%, and the weight percentage of the first binder was 6%. The thickness of the coating was 3 μm.

[0164] Example 5d The process was carried out in accordance with Example 1, except that filler particles were added to the coating. The filler particles were composed of alumina. Based on the total weight of the coating, the weight percentage of organic particles was 70%, the weight percentage of filler particles was 26%, and the weight percentage of the first binder was 4%. The thickness of the coating was 0.5 μm.

[0165] Example 6 group This set of examples illustrates the effects of changes in d / H.

[0166] This embodiment group is carried out with reference to Embodiment 1, except that d / H is changed, as detailed in Tables 1-2.

[0167] Table 1-2 Example 7 group Example 7a The procedure is carried out with reference to Example 1, except that, on the surface of the first adhesive layer, the number of synaptic structures is 25 in an area of ​​500μm × 500μm, and the number of synaptic structures is 6 in an area of ​​100μm × 100μm.

[0168] Example 7b The procedure was carried out with reference to Example 1, except that, on the surface of the first adhesive layer, the number of synaptic structures was 12,223 in an area of ​​500 μm × 500 μm, and the number of synaptic structures was 689 in an area of ​​100 μm × 100 μm.

[0169] Example 7c The procedure is carried out with reference to Example 1, except that, on the surface of the first adhesive layer, the number of synaptic structures is 8 in an area of ​​500μm × 500μm, and the number of synaptic structures is 1 in an area of ​​100μm × 100μm.

[0170] Example 7d The procedure was carried out with reference to Example 1, except that, on the surface of the first adhesive layer, the number of synaptic structures was 18,432 in an area of ​​500 μm × 500 μm, and the number of synaptic structures was 754 in an area of ​​100 μm × 100 μm.

[0171] Example 8 group This embodiment group is based on Example 1, except that the specific selection of the nitrogen-containing fused-ring organic compound, the composition of the first particle, the specific selection of the second polymer, and one or more of the number of synaptic structures in an area of ​​500μm×500μm or in an area of ​​100μm×100μm on the surface of the first adhesive layer are changed, as detailed in Tables 1-3.

[0172] Table 1-3 Comparative Example 1 The procedure was carried out in accordance with Example 1, except that the organic particles were replaced with the same amount of alumina particles by weight.

[0173] Comparative Example 2 The procedure was carried out in accordance with Example 1, except that the components of the organic particles were replaced with 2-mercaptoimidazole and tetramercaptobenzene.

[0174] Test case The batteries prepared by the examples and comparative examples were tested as follows.

[0175] 1. High-temperature cycling performance test The lithium-ion battery was placed at 45℃±3℃, discharged at 0.2C to 3V, allowed to rest for 5 minutes, then charged at a constant current of 0.2C to the upper limit voltage (4.53V), then charged at a constant voltage of 4.53V to 0.025C, allowed to rest for 5 minutes; next, it was discharged at a constant current of 0.2C to 3V, and the discharge capacity at this point was recorded as Q1, allowed to rest for 5 minutes. The battery was then charged at 2.8C to 4.3V, 2C to 4.45V, and 1C to 4.53V (0.2C cutoff), allowed to rest for 5 minutes, and then discharged at 0.7C to 3.0V; allowed to rest for 5 minutes. This constitutes one charge-discharge cycle. After 600 such charge / discharge cycles, the discharge capacity Q2 of the lithium-ion battery at 600T cycles was recorded. The capacity retention rate (%) is calculated as (Q2 / Q1)×100%.

[0176] After the cycle is completed, the battery is disassembled to check the lithium plating on the negative electrode. A value of "0" indicates that the lithium plating area accounts for less than 3% of the total negative electrode area; "1" indicates that the lithium plating area accounts for 3%-10% of the total negative electrode area; "2" indicates that the lithium plating area accounts for more than 10% but less than 20% of the total negative electrode area; "3" indicates that the lithium plating area accounts for 20% or more but less than 35% of the total negative electrode area; "4" indicates that the lithium plating area accounts for 35% or more but less than 50% of the total negative electrode area; and "5" indicates that the lithium plating area accounts for 50% or more of the total negative electrode area.

[0177] 2. Hot Box Test The lithium-ion batteries were heated in a convection air chamber at an initial temperature of (25±3)℃ with a temperature change rate of (5±2)℃ / min, and then heated to (132±1)℃ and (135±1)℃ respectively. The temperature was maintained for 60 minutes before the test was ended, and the battery status was recorded. Ten battery samples were tested for each example and comparative example. If the battery did not explode and / or catch fire, it was considered "passed". If it exploded or caught fire, it was considered "failed". The result was expressed as "number of passes / 10pass". For example, "10 / 10pass" means all passed, and "5 / 10pass" means 5 out of 10 batteries passed.

[0178] 3. Room temperature rate performance test At 25℃±2℃, the battery was discharged to 3V at a constant current of 0.2C, allowed to stand for 10 minutes, then fully charged at 0.7C (100% SOC) with a cutoff current of 0.025C, allowed to stand for 10 minutes, and then discharged to 3V at a rate of 0.5C, allowed to stand for 10 minutes. The discharge capacity at this point was recorded as Q. 1 After standing for 10 minutes, fully charge at 0.7C (100% SOC), with a cutoff current of 0.025C. After standing for 10 minutes, discharge to 3V at a 3C rate. Record the discharge capacity at this point as Q. 2 Rate discharge capacity retention rate: Q 2 / Q 1 ×100%.

[0179] The results are recorded in Table 2.

[0180] Table 2 As can be seen from Table 2, by comparing the comparative examples and the embodiments, the high-temperature cycle capacity retention rate, furnace temperature pass rate, room temperature rate capacity retention rate, and lithium plating of the battery prepared by the embodiments are significantly improved. This indicates that by setting synaptic structures on the surface of at least one adhesive layer in the separator and adding nitrogen-containing fused-ring organic matter to the coating, the battery has both high high-temperature cycle performance and high furnace temperature pass rate.

[0181] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A diaphragm, characterized by The diaphragm comprises a carrier layer and a first adhesive layer, the first adhesive layer is located on at least one side surface of the carrier layer, the first adhesive layer has a porous structure, and the surface of the first adhesive layer comprises a synapse structure; the carrier layer comprises a substrate layer and a coating layer located on one side or both sides of the substrate layer, and the coating layer comprises a nitrogen-containing fused ring organic matter, and the molecular structure of the nitrogen-containing fused ring organic matter comprises a nitrogen-containing fused ring.

2. The septum of claim 1, wherein, The first adhesive layer is located on one side surface of the carrier layer, and the diaphragm further comprises a second adhesive layer, the second adhesive layer is located on the other side surface of the carrier layer, the second adhesive layer has a porous structure or the second adhesive layer comprises third particles; And / or, the thickness of the coating layer is 0.2-5μm, preferably 0.5-3μm; And / or, the coating layer comprises organic particles, and the organic particles comprise a nitrogen-containing fused ring organic matter; And / or, the nitrogen-containing fused heterocyclic ring is a nitrogen-containing fused heterocyclic ring which is unsubstituted or substituted with a characteristic group; Preferably, the nitrogen-containing fused heterocyclic ring comprises one or more of an unsubstituted or substituted benzimidazole ring, an unsubstituted or substituted imidazopyridine, an unsubstituted or substituted imidazopyrazine, an unsubstituted or substituted pyrrolopyrimidine ring, an unsubstituted or substituted quinoline ring and an unsubstituted or substituted cinnoline ring, more preferably, the nitrogen-containing fused heterocyclic ring is an unsubstituted or substituted benzimidazole ring. More preferably, the characteristic group is selected from one or more of C1-C6 alkyl, C1-C6 alkoxy, hydroxyl, amino, carboxyl, cyano, halogen substituent, sulfonic acid group, mercapto and nitro which are unsubstituted or substituted with a substituent R, and the substituent R is selected from one or more of hydroxyl, amino and carboxyl.

3. The septum of claim 2, wherein, The Dv10 of the organic particles is 0.2-0.9μm; And / or, the weight percentage of the organic particles in the coating layer is 70%-98%, preferably 90%-98%; And / or, the surface of the coating layer is observed at a magnification of 20K, and within an optional area of 5μm×5μm, the number of organic particles with a particle size less than 0.1μm is less than or equal to 200. and / or, the nitrogen-containing fused ring organic compound comprises one or more of 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-5-methoxybenzimidazole, 2-mercapto-5-ethoxybenzimidazole, 2-mercapto-5-hydroxybenzimidazole, 2-mercapto-5-aminobenzimidazole, 2-mercapto-5-chlorobenzimidazole, 2-mercapto-5-sulfonic acid benzimidazole, 2-mercapto-5-carboxybenzimidazole, 2-mercapto-5-nitrobenzimidazole, 2-mercapto benzimidazole lithium salt, 2-mercapto benzimidazole sodium salt, 2-mercapto benzimidazole potassium salt, 2-mercapto benzimidazole calcium salt, 2-mercapto benzimidazole magnesium salt, 2-mercapto benzimidazole aluminum salt, 2-mercapto benzimidazole ammonium salt, imidazopyridine-6-methylamine, 7-chloro-imidazopyridine, 5-bromoimidazopyrazine, 2-amino-7H-pyrrolopyrimidine, 5-aminoquinoline, cinnoline-2-thiol, and / or cinnoline-2-amine; or, the second adhesive layer comprises a third polymer and optionally a fourth particle, the third polymer forming a porous structure of the second adhesive layer; or, the third particle comprises a fourth polymer.

4. The septum of claim 1, wherein, The average height of the synaptic structure is 0.1 μm-30 μm, preferably 2 μm-10 μm; and / or, the number of synaptic structures in an area of 500 μm×500 μm of the surface of the first adhesive layer is greater than 10, and the number of synaptic structures in an area of 100 μm×100 μm of the surface of the first adhesive layer is less than 1000; and / or, the first adhesive layer is used on the side of the positive electrode sheet; and / or, the synaptic structure comprises a first particle, the first particle comprising a first polymer; and / or, the synaptic structure partially or entirely protrudes from the surface of the first adhesive layer; and / or, the first adhesive layer comprises a second polymer and optionally a second particle, the second polymer forming a porous structure of the first adhesive layer; and / or, the coating further comprises a first binder, the weight percentage of the first binder in the coating is 1%-15%; and / or, the coating further comprises filler particles, the weight percentage of the filler particles in the coating is 1%-26%.

5. The septum of claim 3 or 4, wherein, The first polymer, the second polymer, the third polymer and the fourth polymer each independently comprise one or more of fluorine-containing polymer, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl acetate, polyacrylamide, epoxy resin, ethylene-vinyl acetate copolymer, polyacrylic acid copolymer, lithium polystyrene sulfonate, polyvinylidene fluoride-trichloroethylene, polyvinylidene fluoride-chlorotrifluoroethylene, polyethylene oxide, cyanoethyl polyvinyl alcohol, butadiene-acrylonitrile copolymer and its derivatives, aramid, phenolic resin, modified phenolic resin, polyimide, polyetherimide, modified polyimide. and / or, the second particles and the fourth particles each independently comprise one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silica, tin dioxide, titanium oxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, aluminum nitride, boron nitride, zirconium titanate, barium titanate, magnesium fluoride, melamine cyanurate, 1,3,5-triazine-2,4,6-triamine, melamine trimer thiocyanate, uracil, cytosine, guanine, N,N'-di(β-naphthyl)para-phenylenediamine, 4-amino-2,6-dihydroxypyrimidine, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole derivatives; and / or, the second particles in the first adhesive layer account for 0-70% by weight; and / or, the first adhesive comprises one or more of polyvinyl alcohol, styrene butadiene rubber, ethylene-vinyl acetate copolymer, sodium carboxymethyl cellulose, polyvinyl pyrrolidone, styrene-acrylate latex, polyacrylonitrile, acrylate polymer, polyvinyl acetate, acrylic polymer, polyurethane, fluoropolymer, or a copolymer system derived from the above polymers; and / or, the filler particles comprise one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silica, tin dioxide, titanium oxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, aluminum nitride, boron nitride, zirconium titanate, barium titanate, melamine cyanurate, 1,3,5-triazine-2,4,6-triamine, melamine trimer thiocyanate, uracil, cytosine, guanine, N,N'-di(β-naphthyl)para-phenylenediamine, 4-amino-2,6-dihydroxypyrimidine, phenolic resin.

6. The septum of claim 5, wherein, The acrylate polymer comprises one or more of polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymer, acrylate monomer-ethylene copolymer, acrylate monomer-acrylonitrile-ethylene copolymer, styrene-acrylate monomer-acrylonitrile copolymer, ethylhexyl acrylate-methyl methacrylate copolymer, butyl acrylate-methyl methacrylate copolymer, methyl acrylate-N,N-dimethyl acrylamide copolymer, ethyl acrylate-acrylic acid-2-(diethylamino)ethyl acrylate copolymer, ethyl acrylate-acrylic acid-N,N-diethyl acrylamide copolymer, ethyl acrylate-acrylic acid-2-(diethylamino)ethyl acrylate, and preferably, the acrylate monomer comprises one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate; And / or, the 2-mercapto benzimidazole derivatives include one or more of 2-mercapto-5-methyl benzimidazole, 2-mercapto-5-methoxy benzimidazole, 2-mercapto-5-ethoxy benzimidazole, 2-mercapto-5-hydroxy benzimidazole, 2-mercapto-5-amino benzimidazole, 2-mercapto-5-chloro benzimidazole, 2-mercapto-5-sulfonic acid benzimidazole, 2-mercapto-5-carboxyl benzimidazole, 2-mercapto-5-nitro benzimidazole, 2-mercapto benzimidazole lithium salt, 2-mercapto benzimidazole sodium salt, 2-mercapto benzimidazole potassium salt, 2-mercapto benzimidazole calcium salt, 2-mercapto benzimidazole magnesium salt, 2-mercapto benzimidazole aluminum salt, 2-mercapto benzimidazole ammonium salt.

7. The separator of any one of claims 1-6, wherein, The thickness of the first adhesive layer is 0.5-5 μm; And / or, the first adhesive layer is continuously coated or discontinuously coated on the surface of the carrier layer; And / or, the thickness of the substrate layer is 3-16 μm, preferably 4-9 μm; And / or, the porosity of the substrate layer is 30-75%, preferably 38-55%; And / or, the average pore size of the substrate layer is 30-55 nm; And / or, the components of the substrate layer include one or more of polyolefin, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyethylene terephthalate, polybutylene terephthalate, poly(m-phenylene terephthalamide), or derivatives of the above polymers.

8. A battery, characterized by The battery comprises a positive electrode sheet, a negative electrode sheet, an electrolyte, and the separator of any one of claims 1-7, the separator being located between the positive electrode sheet and the negative electrode sheet.

9. The battery of claim 8, wherein, The positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer located on one side or both sides of the positive electrode current collector, the positive electrode active layer comprising positive electrode active particles, and the battery satisfies the following relationship: 0.2 And / or, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer located on one side or both sides of the negative electrode current collector, the negative electrode active layer comprising a silicon-based material, the silicon-based material comprising one or more of elemental silicon particles, silicon oxide particles, silicon-carbon composite particles, silicon-nitrogen composite particles, and silicon alloy particles; And / or, the electrolyte comprises a polar solvent selected from at least one of 2,2-difluoroethyl acetate, ethyl 2,2-difluoroacetate, propyl propionate, ethyl propionate, diethyl carbonate, propylene carbonate, and ethylene carbonate.

10. The battery of claim 9, wherein, The Dv50 of the positive electrode active particles is 2-20 μm; And / or, the average height H of the synaptic structure is 0.1-30 μm, preferably 2-10 μm; And / or, the components of the positive electrode active particles include one or more of lithium nickelate, lithium titanate, lithium cobaltate, lithium nickel-cobalt-manganese oxide, lithium nickel-cobalt-aluminum oxide, lithium iron phosphate, and lithium manganate. And / or, the average particle size of the silicon-carbon composite particles is 5 μm to 12 μm. And / or, the average particle size of the silicon-carbon composite particles is 5 μm to 12 μm.

Images