Composite lithium supplement material and preparation method thereof, positive plate, battery and electric equipment

Abstract

The invention provides a composite lithium supplement material and a preparation method thereof, a positive plate, a battery and electric equipment wherein the composite lithium supplement material comprises an inner core, a first coating layer and a second coating layer, the first coating layer is arranged on at least part of the surface of the inner core, and the second coating layer is arranged on the surface of the inner core. The second coating layer is arranged on the surface of the first coating layer, or the surface of the first coating layer and the surface of the inner core; the inner core comprises a lithium-rich lithium-supplementing material doped with a chlorine element, the first coating layer comprises a carbon material doped with the chlorine element, and the second coating layer comprises a metal oxide and / or a metal nitride. The composite lithium supplementing material has relatively high conductivity and air stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries and relates to a composite lithium supplement material, in particular to a composite lithium supplement material and a preparation method thereof, a positive electrode sheet, a battery and an electrical device. Background Art

[0002] Lithium-ion batteries, due to their long cycle life, low self-discharge rate, lack of memory effect, strong adaptability to high and low temperatures, and environmental friendliness, are widely used in various fields, such as electric vehicles, consumer electronics, energy storage, aerospace, and medical equipment. The continuous development of lithium-ion batteries has placed higher demands on battery endurance, which is closely related to the battery's energy density. However, during the battery's initial charge and discharge, irreversible lithium ion loss inevitably occurs, resulting in a decrease in the battery's initial coulombic efficiency and, in turn, influencing its capacity. This is because the formation of the solid electrolyte interface film (SEI) on the negative electrode surface consumes some of the lithium ions that migrate from the positive electrode to the negative electrode. Therefore, lithium replenishment technology has emerged to compensate for this irreversible lithium loss.

[0003] Currently, lithium replenishment technologies are mainly divided into negative electrode replenishment and positive electrode replenishment. Compared with negative electrode replenishment technology, positive electrode replenishment technology has the advantages of simple process, low cost, and better safety. Therefore, it has been widely used in fields that pursue high cost performance and high safety. Positive electrode replenishment technology usually adds lithium replenishment materials during the preparation of positive electrode active slurry, without changing the battery process and equipment, and can effectively compensate for the loss of lithium ions during the initial charge and discharge. However, the commonly used lithium-rich lithium replenishment materials currently have defects such as poor conductivity or poor air stability, which cannot significantly improve the initial coulombic efficiency of the battery.

[0004] Therefore, it is necessary to further improve the conductivity and air stability of lithium-supplementing materials. Summary of the Invention

[0005] In view of the above-mentioned defects, the present invention provides a composite lithium-supplementing material, which has high conductivity and air stability.

[0006] The present invention also provides a method for preparing the composite lithium-supplementing material. The composite lithium-supplementing material prepared by the method has high electrical conductivity and air stability.

[0007] The present invention also provides a positive electrode sheet, which includes the above-mentioned composite lithium-supplementing material or the composite lithium-supplementing material prepared by the above-mentioned preparation method. Therefore, applying the positive electrode sheet to a battery can effectively improve the first coulombic efficiency of the battery.

[0008] The present invention also provides a battery comprising the composite lithium-supplementing material, or the composite lithium-supplementing material prepared by the preparation method, or the positive electrode sheet, so that the battery has a high first coulombic efficiency.

[0009] The present invention also provides a battery pack comprising the above-mentioned battery, so that the battery pack can achieve a higher first coulombic efficiency.

[0010] The present invention also provides an electrical device comprising the above-mentioned battery or the above-mentioned battery pack, so that the electrical device has a longer service life.

[0011] A first aspect of the present invention provides a composite lithium supplement material, comprising a core, a first coating layer, and a second coating layer, wherein the first coating layer is disposed on at least a portion of the surface of the core, and the second coating layer is disposed on at least a portion of the surface of the first coating layer, or at least a portion of the surface of the first coating layer and at least a portion of the surface of the core;

[0012] The core includes a lithium-rich lithium-supplementing material doped with chlorine, the first coating layer includes a carbon material doped with chlorine, and the second coating layer includes a metal oxide and / or a metal nitride.

[0013] The composite lithium supplement material as described above, wherein the carbon material doped with chlorine is obtained by carbonizing a raw material including a chlorine-containing organic polymer; preferably, the carbonization temperature is 400° C. to 1000° C., and the carbonization time is 2 h to 16 h.

[0014] In the composite lithium supplement material as described above, the chlorine-containing organic polymer includes at least one of polyvinyl chloride, polypropylene chloride, polychloroprene, polyvinylidene chloride, chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and chlorosulfonated polyethylene.

[0015] The composite lithium-supplementing material as described above, wherein the lithium-rich lithium-supplementing material includes Li5FeO4 and / or Li2NiO2.

[0016] The composite lithium-supplementing material as described above, wherein the metal oxide includes at least one of Al2O3, SiO2, TiO2, NiO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, In2O3, SnO2, HfO2, and Ta2O5; and / or the metal nitride includes at least one of AlN, TiN, CoN, GaN, ZrN, NbN, MoN, InN, HfN, TaN, and WN.

[0017] The composite lithium supplement material as described above, wherein the thickness of the first coating layer is 0.01 μm to 1 μm, and / or the thickness of the second coating layer is 0.1 nm to 10 nm.

[0018] The composite lithium-supplementing material as described above, wherein the mass content of chlorine element in the composite lithium-supplementing material is 1000ppm~70000ppm.

[0019] The composite lithium-supplementing material as described above, wherein the particle size D99 of the composite lithium-supplementing material is 1 μm to 30 μm.

[0020] The second aspect of the present invention provides a method for preparing the composite lithium supplement material of the first aspect, comprising the following steps:

[0021] 1) Sintering a raw material comprising a lithium-rich lithium-supplementing material and a chlorine-containing organic polymer to obtain a coated product; the coated product comprises a core and a first coating layer coating at least a portion of the surface of the core, wherein the core comprises the lithium-rich lithium-supplementing material doped with chlorine, and the first coating layer comprises a carbon material doped with chlorine;

[0022] 2) placing the coated product into an atomic deposition device, introducing a metal oxide source and / or a metal nitride source into the atomic deposition device for reaction, and depositing a second coating layer on the surface of the coated product to obtain the composite lithium supplement material.

[0023] The method for preparing the composite lithium supplement material as described above, wherein, in step 1), the sintering temperature is 400°C to 1000°C and the time is 2h to 16h; and / or, in step 2), the reaction temperature in the atomic deposition equipment is 25°C to 400°C.

[0024] The preparation method of the composite lithium supplement material as described above, wherein the metal oxide source includes a first metal source and an oxygen source; the metal oxide source includes a first metal source and an oxygen source; the first metal source includes Al(NEt2)3, Al(NMe2)3, Al(OEt)3, AlCl3, AlEt3, AlMe2Cl, AlMe2H, AlMe3, Si(OEt)4, Si(OMe)4, Si2Cl6, Si2H6, SiCl2H2, SiCl3H, SiCl4, SiH(NMe2)3, SiH2(NEt2)2, SiH2(NMe2)2, SiH4, Ti(CpMe5)(OMe3), Ti(Et Cp)(NMe2)3, Ti(NEt2)4, Ti(NMe2)3(CpMe), Ti(NMe2)3(CpN), Ti(NMe2)4, Ti(NMeEt)4, Ti(OEt)4, Ti(OMe)4, TiCl4, TiF4, TiI4, Ni(CpEt)2, Ni(M eCp)2, NiCp2, Zn, Zn(OAc)2, ZnCl2, ZnEt2, ZnMe2, Ga2(NMe2)6, GaEt3, GaMe3, Y(CpBu)3, Y(CpEt)3, Y(CpMe)3, YCp3, Zr(Cp2CMe2)Me(OMe), Zr(Cp2 CMe2)Me2, Zr(CpEt)(NMe2)3, Zr(CpMe)(NMe2)3, Zr(CpMe)2Me(OMe), Zr(CpMe)2Me2, Zr(NEt2)4, Zr(NEtMe)4, Zr(NMe2)4, ZrCl4, ZrCp(NMe2)3, Z rCp2Cl2, ZrCp2Me(OMe), ZrCp2Me2, ZrI4, Nb(OEt)5, In(PrNMe2)Me2, InCl3, InEt3, InMe3, InMe3(NMe2Bu), Sn(NEtMe)4, Sn(NMe2)4, SnCl4, SnEt4 , SnI4, SnMe4, Hf(Cp)(NMe2)3, Hf(Cp2CMe2)Me(OMe), Hf(Cp2CMe2)Me2, Hf(CpMe)(NMe2)3, Hf(CpMe)2(OMe)Me, Hf(CpMe)2Me2, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Hf(ONEt2)4, HfCl4, HfCp2Cl2, HfCp2Me2, HfI4, Ta(NEt)(NEt2)3, Ta(NEt2)5, Ta(NMe2)5, Ta(OEt)5, TaCl5, TaF5, TaI5;The oxygen source includes at least one of O2, O3, H2O, H2O2, N2O, N2O4, MeOH, and EtOH.

[0025] The preparation method of the composite lithium supplement material as described above, wherein the metal nitride source includes a second metal source and a nitrogen source; the second metal source includes Al(NEt2)3, Al(NMe2)3, AlCl3, AlEt3, AlH2(NMe2), AlMe3, Ti(NEt2)4, Ti(NEtMe)4, Ti(NMe2)4, TiCl4, TiI4, CoCp2, Ga, GaCl3, GaEt3, GaMe3, Zn(NMe2)4, Zr(NEt2)4, Zr(NEt At least one of: Me)4, Zr(NMe2)4, ZrCp2(NMe2)2, NbCl5, MoCl5, In, InEtMe2, InMe3, Hf(Cp)(NMe2)3, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Ta(NEtMe)5, Ta(NMe2)5, TaBr5, TaCl5, TaF5, W2(NMe2)6, and WF6; and the nitrogen source includes at least one of NH3, N2H4, N2, and Me2NNH2.

[0026] A third aspect of the present invention provides a positive electrode sheet, which includes the composite lithium-supplementing material of the first aspect, or the composite lithium-supplementing material prepared by the preparation method of the second aspect.

[0027] A fourth aspect of the present invention provides a battery, which includes the composite lithium-supplementing material of the first aspect, or the composite lithium-supplementing material prepared by the preparation method of the second aspect, or the positive electrode sheet of the third aspect.

[0028] A fifth aspect of the present invention provides a battery pack comprising at least two batteries according to the fourth aspect.

[0029] A sixth aspect of the present invention provides an electrical device, which includes the battery of the fourth aspect or the battery pack of the fifth aspect.

[0030] The composite lithium-supplementing material of the present invention includes a core and a first coating layer and a second coating layer sequentially coated on the surface of the core. The core includes a lithium-rich lithium-supplementing material doped with chlorine, the first coating layer includes a carbon material doped with chlorine, and the second coating layer includes a metal oxide and / or metal nitride. The lattice of the lithium-rich lithium-supplementing material and the carbon material of the first coating layer are both doped with chlorine, which can effectively improve the lithium ion migration rate and electronic conductivity. At the same time, the metal oxide and / or metal nitride in the second coating layer can effectively improve the air stability and conductivity of the composite lithium-supplementing material. Therefore, the composite lithium-supplementing material of the present invention has high air stability and conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the composite lithium supplement material in one embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 1-first coating layer;

[0034] 2- second coating layer;

[0035] 3-Core. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] Currently, lithium-rich materials (such as Li5FeO4 and Li2NiO2) are commonly used to compensate for the irreversible lithium loss during the battery's initial charge and discharge cycles. While these materials' lithium-rich properties can compensate for lithium loss to a certain extent, the strong reducing properties of lithium and the instability of high-valent transition metals also lead to poor air stability. They are prone to reactions in air, leading to structural collapse and loss of effectiveness. Furthermore, the electronic conductivity of these materials is low, making it difficult to significantly improve the battery's initial coulombic efficiency.

[0038] In the existing technology, the electronic conductivity and air stability of lithium-rich lithium-supplementing materials are mainly improved by carbon coating or coating with other materials, but the improvement of material performance is limited; and in the coating process, high-temperature solid-phase sintering coating is usually adopted. This coating method cannot accurately control the uniformity and thickness of the coating layer, which will have a negative impact on the air stability and conductivity of the lithium-rich lithium-supplementing materials, and is not conducive to improving the first coulombic efficiency of the battery.

[0039] To address the above issues, the inventors have discovered that using a chlorine-containing organic polymer instead of conventional carbon coating can effectively improve the ion transport efficiency and electronic conductivity of lithium-rich supplementary materials. The inventors believe this may be due to the following: During the sintering process of the chlorine-containing organic polymer and the lithium-rich supplementary material, the chlorine-containing organic polymer undergoes carbonization and decomposition at high temperatures, generating carbon material and gases such as hydrogen, chlorine, and hydrogen chloride. The carbon material directly coats at least a portion of the surface of the lithium-rich supplementary material, forming a carbon coating layer. The gases then react with the carbon coating layer (hereinafter referred to as the first coating layer) and the lithium-rich supplementary material, becoming doped into the lattice structure of the carbon material and the lithium-rich supplementary material. Doping with chlorine can introduce additional charge carriers (electrons or holes), change the electronic structure and energy band structure inside the material, affect the material's electron transport ability, and promote the migration of lithium ions; in addition, chlorine has a high electronegativity and can easily form stable chemical bonds with other elements, thereby improving the overall structural stability of the material; at the same time, doping with chlorine can also change the surface properties of lithium-rich lithium-supplemented materials and carbon materials, making them hydrophobic to a certain extent, protecting them from moisture erosion in the air, thereby improving the material's air stability.

[0040] However, carbon coating of chlorine-containing organic polymers at high temperatures may result in uneven and incomplete coating layers, resulting in partial surface exposure of the lithium-rich lithium-supplementing material to the air, which is not conducive to improving the conductivity and air stability of the material. In order to solve the above problems, the inventors attempted to use an atomic deposition device to coat the outer surface of the lithium-rich lithium-supplementing material coated with chlorine-doped carbon material with another coating layer (hereinafter referred to as the second coating layer). During the coating process, the coating uniformity and coating layer thickness can be precisely controlled to improve the overall integrity and uniformity of the coating layer, and avoid the reduction in the proportion of active materials caused by excessive thickness, thereby reducing the loss of energy density. At the same time, the coating layer also includes metal oxides and / or metal nitrides, wherein the metal oxides can play an insulating role and improve the stability of the lithium-rich lithium-supplementing material, and the metal nitrides can improve the stability and electrical conductivity of the material.

[0041] Therefore, by doping the lithium-rich lithium-supplementing material with chlorine and coating its surface with a carbon material doped with chlorine to form a first coating layer, and coating the surface of the first coating layer with a second coating layer comprising metal oxide and / or metal nitride, the electronic conductivity, ion transmission rate and air stability of the lithium-rich lithium-supplementing material can be effectively improved.

[0042] Based on the above analysis, the first aspect of the present invention provides a composite lithium-supplementing material, which includes a core, a first coating layer and a second coating layer. The first coating layer is arranged on at least a portion of the surface of the core, and the second coating layer is arranged on at least a portion of the surface of the first coating layer, or at least a portion of the surface of the first coating layer and at least a portion of the surface of the core; the core includes a lithium-rich lithium-supplementing material doped with chlorine, the first coating layer includes a carbon material doped with chlorine, and the second coating layer includes a metal oxide and / or a metal nitride.

[0043] Figure 1 This is a schematic structural diagram of the composite lithium supplement material in one embodiment of the present invention. Figure 1 In the embodiment, the surface of the core 3 is covered with a first covering layer 1 , and the surface of the first covering layer 1 away from the core 3 is covered with a second covering layer 2 .

[0044] The composite lithium-replenishing material of the present invention comprises a core lithium-rich lithium-replenishing material, and a first coating layer (a carbon material doped with chlorine) and a second coating layer (a metal oxide and / or metal nitride) sequentially coated on the surface of the core. The chlorine-doped lithium-rich lithium-replenishing material and the first coating carbon material can alter the internal electronic structure and energy band structure of the material, affecting the material's electron transport capacity and promoting lithium ion migration. Chlorine also readily forms stable chemical bonds with other elements, enhancing the overall structural stability of the material. Furthermore, the chlorine doping can also enhance the material's hydrophobicity to a certain extent, protecting it from moisture erosion in air and improving its air stability. The metal oxide and / or metal nitride included in the second coating layer further enhances the material's air stability and electrical conductivity. Therefore, the composite lithium-replenishing material exhibits high air stability and electrical conductivity.

[0045] The "lithium-rich lithium-supplementing material doped with chlorine" and the "carbon material doped with chlorine" in the present invention can be obtained by mixing and sintering raw materials including a chlorine-containing organic polymer and a lithium-rich lithium-supplementing material.

[0046] In a specific embodiment, the carbon material doped with chlorine is obtained by carbonizing a raw material including a chlorine-containing organic polymer; preferably, the carbonization temperature is 400° C. to 1000° C., and the carbonization time is 2 h to 16 h.

[0047] Illustratively, the temperature of the carbonization treatment can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, or a range consisting of any two values ​​therein; the time of the carbonization treatment can be 2h, 4h, 6h, 8h, 10h, 12h, 14h or 16h, or a range consisting of any two values ​​therein.

[0048] The "chlorine-containing organic polymer" in the present invention refers to an organic high molecular weight compound containing chlorine. The present invention does not specifically limit the molecular weight of the chlorine-containing organic polymer. In one embodiment, the number average molecular weight of the chlorine-containing organic polymer is 10,000 to 300,000.

[0049] The present invention does not specifically limit the source of the chlorine-containing organic polymer, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0050] Specifically, chlorine-containing organic compounds can also be screened to enhance the doping effect of the chlorine element, thereby enhancing the electrical conductivity, ion conductivity, and air stability of the composite lithium-supplementing material.

[0051] In a specific embodiment, the chlorine-containing organic polymer includes at least one of polyvinyl chloride, polypropylene chloride, polychloroprene, polyvinylidene chloride, chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and chlorosulfonated polyethylene.

[0052] When the chlorine-containing organic polymer comprises a plurality of the aforementioned specific compounds at the same time, the present invention does not impose any specific limitation on the ratio of the specific compounds.

[0053] Furthermore, the types of lithium-rich and lithium-supplementing materials can also be screened.

[0054] In one embodiment, the lithium-rich lithium supplement material includes Li5FeO4 and / or Li2NiO2. The theoretical charge capacity of Li5FeO4 is as high as 700 mAh / g. Using Li5FeO4 as the lithium supplement material can further improve the initial charge capacity of the battery.

[0055] Furthermore, metal oxides and metal nitrides can be screened to improve the conductivity and air stability of the composite lithium-supplementing materials.

[0056] In a specific embodiment, the metal oxide includes at least one of Al2O3, SiO2, TiO2, NiO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, In2O3, SnO2, HfO2, and Ta2O5.

[0057] When the metal oxide includes multiple specific compounds mentioned above at the same time, the present invention does not specifically limit the ratio of each specific compound.

[0058] The present invention does not specifically limit the source of the aforementioned metal oxides, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0059] In a specific embodiment, the metal nitride includes at least one of AlN, TiN, CoN, GaN, ZrN, NbN, MoN, InN, HfN, TaN, and WN.

[0060] When the metal nitride includes the aforementioned multiple specific compounds at the same time, the present invention does not specifically limit the ratio of each specific compound.

[0061] The present invention does not specifically limit the source of the aforementioned metal nitrides, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0062] Furthermore, the thickness of both the first and second coating layers affect the conductivity, air stability, and lithium replenishment effectiveness of the composite lithium-replenishing material. A moderate first coating layer thickness helps form a more uniform and complete coating, resulting in a higher overall conductivity for the material. It also avoids the extended lithium-ion diffusion path caused by excessive thickness, helping to improve the material's lithium-ion diffusion capacity. Furthermore, since both metal oxides and metal nitrides are inactive substances and do not participate in electrochemical reactions during battery operation, a suitable second coating layer thickness not only ensures air insulation but also reduces capacity loss.

[0063] In a specific embodiment, the thickness of the first coating layer is 0.01 μm to 1 μm. Within this range, the thickness of the first coating layer is relatively appropriate, and a balance between the conductivity and activity of the composite lithium supplement material can be achieved.

[0064] Illustratively, the thickness of the first coating layer may be 0.01 μm, 0.02 μm, 0.25 μm, 0.5 μm, 0.75 μm, 0.8 μm or 1 μm, or a range consisting of any two of these values.

[0065] In one embodiment, the thickness of the second coating layer is 0.1 nm to 10 nm. Within this range, the thickness of the second coating layer is moderate, which not only reduces the loss of activity but also improves the air stability of the material, thereby improving the initial charge specific capacity of the battery.

[0066] Illustratively, the thickness of the second cladding layer may be 0.1 nm, 0.5 nm, 1 nm, 2 nm, 4 nm, 6 nm, 8 nm or 10 nm, or a range consisting of any two of these values.

[0067] The “thickness of the first coating layer” and the “thickness of the second coating layer” in the present invention can be measured using a transmission electron microscope (TEM).

[0068] Furthermore, the mass content of chlorine in the composite lithium supplement material will also have a certain impact on the overall performance of the battery, so the content of chlorine also needs to be controlled.

[0069] In one embodiment, the chlorine content of the composite lithium-supplementing material is between 1,000 ppm and 70,000 ppm by mass. Within this range, the chlorine content of the composite lithium-supplementing material is moderate, effectively improving the conductivity and stability of the composite lithium-supplementing material while also reducing irreversible loss of active lithium and avoiding lattice distortion and phase separation, thereby effectively enhancing the lithium-supplementing effect.

[0070] For example, the mass content of chlorine in the lithium supplementing material may be 1000 ppm, 5000 ppm, 10000 ppm, 20000 ppm, 30000 ppm, 40000 ppm, 50000 ppm, 60000 ppm, 70000 ppm, or a range consisting of any two of these values.

[0071] The mass content of the chlorine element in the lithium-supplementing material of the present invention can be measured by inductively coupled plasma (ICP) technology.

[0072] In one embodiment, the particle size D99 of the composite lithium-supplementing material is between 1 μm and 30 μm. Within this range, the composite lithium-supplementing material has a relatively moderate particle size, which not only provides a high ion diffusion rate and mechanical strength, but also avoids the increase in battery internal resistance caused by an excessively small particle size, further enhancing the lithium-supplementing effect of the composite lithium-supplementing material.

[0073] For example, the particle size D99 of the composite lithium supplement material may be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, or a range consisting of any two of these values.

[0074] The "particle size D99" in the present invention refers to the particle size distribution of the lithium supplement material, in which 99% of the particles have a diameter less than or equal to this value, which can be obtained by testing with a laser particle size analyzer.

[0075] The second aspect of the present invention provides a method for preparing the composite lithium supplement material of the first aspect, comprising the following steps:

[0076] 1) sintering a raw material comprising a lithium-rich lithium-supplementing material and a chlorine-containing organic polymer to obtain a coated product; the coated product comprises a core and a first coating layer coating at least a portion of the surface of the core, wherein the core comprises the lithium-rich lithium-supplementing material doped with chlorine, and the first coating layer comprises a carbon material doped with chlorine;

[0077] 2) placing the coated product into an atomic deposition device, introducing a metal oxide source and / or a metal nitride source into the atomic deposition device for reaction, and depositing a second coating layer on the surface of the coated product to obtain a composite lithium supplement material.

[0078] Specifically, in step 1), a raw material of a lithium-rich lithium-supplementing material and a chlorine-containing organic polymer are uniformly mixed to obtain a mixed material; the mixed material is sintered; during the sintering process, the chlorine-containing organic polymer is carbonized to obtain a carbon material and gases such as hydrogen, chlorine, and hydrogen chloride, wherein the carbon material is directly coated on at least a portion of the surface of the lithium-rich lithium-supplementing material to form a first coating layer; the gases react with the first coating layer and the lithium-rich lithium-supplementing material, being doped into the carbon material and the lattice structure of the lithium-rich lithium-supplementing material to obtain a coated product. The coated product includes a core and a first coating layer coating at least a portion of the surface of the core, wherein the core includes the lithium-rich lithium-supplementing material doped with chlorine, and the first coating layer includes the carbon material doped with chlorine.

[0079] The present invention does not impose specific restrictions on the mass ratio of the lithium-rich lithium-supplementing material to the chlorine-containing organic polymer; it can be adjusted based on the coating structure of the composite lithium-supplementing material. Specifically, the thickness of the first coating layer can be adjusted by adjusting the mass ratio of the lithium-rich lithium-supplementing material to the chlorine-containing organic polymer. Preferably, the mass ratio of the lithium-rich lithium-supplementing material to the chlorine-containing organic polymer is (10-200):1. When the mass ratio is within this range, the thickness of the first coating layer is preferably between 0.01μm and 1μm.

[0080] Illustratively, the mass ratio of the lithium-rich lithium-supplementing material to the chlorine-containing organic polymer can be 10:1, 20:1, 40:1, 60:1, 80:1, 100:1, 120:1, 140:1, 160:1, 180:1 or 200:1, or a range consisting of any two values ​​therein.

[0081] The present invention does not impose any specific restrictions on the particle size D99 of the lithium-rich lithium-supplementing material. Preferably, the particle size D99 is 1 μm to 25 μm. Within this range, the particle size D99 of the composite lithium-supplementing material is preferably between 1 μm and 30 μm.

[0082] For example, the particle size D99 of the lithium-rich lithium-supplementing material may be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm or 25 μm, or a range consisting of any two of these values.

[0083] The present invention does not impose any specific restrictions on the sources of the lithium-rich lithium-supplementing material and the chlorine-containing organic polymer, which can be consistent with the above-mentioned restrictions and will not be elaborated here.

[0084] The chlorine-containing organic polymer in the present invention is preferably at least one of polyvinyl chloride, polypropylene chloride, polychloroprene, polyvinylidene chloride, chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and chlorosulfonated polyethylene.

[0085] The present invention does not impose any specific limitation on the heating rate during sintering, and a suitable heating rate can be selected according to actual conditions. In one embodiment, the heating rate is 1° C. / min to 10° C. / min.

[0086] The present invention does not impose any specific limitation on the mixing method of the lithium-rich lithium-supplementing material and the chlorine-containing organic polymer. It is sufficient that the two are uniformly mixed. For example, the mixing can be carried out by at least one of stirring mixing, oscillating mixing, and convection mixing.

[0087] In step 2), dry air is introduced into the atomic deposition device in advance to fill the reaction chamber of the atomic deposition device with air; then the coated product is placed in the atomic deposition device, quickly evacuated, and the temperature of the reaction chamber is raised to the set reaction temperature; then a metal oxide source and / or a metal nitride source is introduced into the atomic deposition device to react and deposit on the surface of the coated product to obtain a composite lithium supplement material.

[0088] The present invention does not impose any specific restrictions on the heating rate during the heating process of the reaction chamber and can be adjusted according to actual conditions. In one embodiment, the heating rate is 1°C / min to 10°C / min. Exemplarily, the heating rate is 1°C / min, 2°C / min, 4°C / min, 6°C / min, 8°C / min, or 10°C / min, or a range consisting of any two of these values.

[0089] It should be noted that when the second coating layer is a metal oxide, a metal oxide source is introduced into the atomic deposition equipment. The metal oxide source includes a first metal source and an oxygen source. The first metal source and the oxygen source react on the surface of the coated product. The resulting reaction product is the metal oxide, which is deposited on the surface of the coated product to form a second coating layer.

[0090] Specifically, in one embodiment, introducing a metal oxide source includes: first introducing a first metal source into the atomic deposition device for a first specified time, then introducing an inert gas into the atomic deposition device for a second specified time to remove excess first metal source in the reaction chamber, then introducing an oxygen source into the atomic deposition device for a third specified time to allow the oxygen source to react with the first metal source to generate metal oxide and deposit it on the surface of the coated product to form a second coating layer, and finally introducing an inert gas into the atomic deposition device for a fourth specified time to clean and remove excess oxygen source in the reaction chamber.

[0091] When the second coating layer is a metal nitride, a metal nitride source is introduced into the atomic deposition equipment. The metal nitride source includes a second metal source and a nitrogen source. The second metal source and the nitrogen source react on the surface of the coated product. The resulting reaction product is a metal nitride, which is deposited on the surface of the coated product to form a second coating layer.

[0092] Specifically, in one embodiment, introducing a metal nitride source includes: first introducing a second metal source into the atomic deposition device for a fifth specified time, then introducing an inert gas into the atomic deposition device for a sixth specified time to remove excess second metal source in the reaction chamber, then introducing a nitrogen source into the atomic deposition device for a seventh specified time to allow the nitrogen source to react with the second metal source to generate a metal nitride and deposit it on the surface of the coated product to form a second coating layer, and finally introducing an inert gas into the atomic deposition device for an eighth specified time for cleaning to remove excess nitrogen source in the reaction chamber.

[0093] The first to eighth designated times in the present invention may be the same or different, and appropriate times may be selected based on actual circumstances. In one embodiment, the first to eighth designated times are each independently 5 seconds to 30 seconds; illustratively, the first to eighth designated times may each independently be 5 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds, or 30 seconds, or a range consisting of any two of these values.

[0094] The present invention does not specifically limit the type of the inert gas. For example, the inert gas may be at least one of nitrogen, argon, helium, and neon.

[0095] When the second coating layer is a metal nitride and a metal oxide, a metal nitride source and a metal oxide source can be alternately introduced into the atomic deposition apparatus. The order of introducing the metal nitride source and the metal oxide source is not specifically limited and can be adjusted according to the coating layer structure of the composite lithium-supplementing material. The number of times the metal nitride source and the metal oxide source are alternately introduced is not specifically limited and can be adjusted according to the thickness of the second coating layer. For example, if the coating layer closest to the center of the composite lithium-supplementing material in the second coating layer is a metal oxide layer, then during the actual deposition process, the metal oxide can be introduced first and then the metal nitride source can be introduced; conversely, if the coating layer closest to the center of the composite lithium-supplementing material in the second coating layer is a metal nitride layer, then during the actual deposition process, the metal nitride source can be introduced first and then the metal oxide source can be introduced.

[0096] It can be understood that during the deposition process, the thickness of the metal nitride can be controlled by adjusting the number of times a metal nitride source is introduced into the atomic layer deposition apparatus to deposit a nitride layer; similarly, the thickness of the metal oxide can be controlled by adjusting the number of times a metal oxide source is introduced into the atomic layer deposition apparatus to deposit a metal oxide layer, and each deposition can achieve atomic-level thickness control of at least 0.1 nm. For example, the number of times a metal nitride source is introduced to deposit a nitride layer can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 times; the number of times a metal oxide source is introduced to deposit a metal oxide layer can also be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 times.

[0097] The preparation method of the composite lithium-supplementing material in the present invention is to first mix and sinter the lithium-rich lithium-supplementing material with a chlorine-containing organic polymer, and the chlorine-containing organic polymer is carbonized and decomposed at high temperature to generate carbon material and gases such as hydrogen, chlorine and hydrogen chloride, wherein the carbon material is directly coated on at least part of the surface of the lithium-rich lithium-supplementing material, and the chlorine-containing gas reacts with the carbon coating layer and the lithium-rich lithium-supplementing material, and is doped into the lattice structure of the carbon material and the lithium-rich lithium-supplementing material. The doping of chlorine elements can change the electronic structure and energy band structure inside the material, improve the electrical conductivity and ion transport performance of the material; at the same time, chlorine can also form stable chemical bonds with other elements, further improving the structural stability of the material; in addition, chlorine elements can also change the surface properties, give the material a certain hydrophobicity, and improve the air stability of the material. Subsequently, the above-mentioned coated product is secondary coated by atomic deposition technology, and metal oxides and / or metal nitrides are coated to further improve the air stability and conductivity of the material, and the thickness of the coating layer can be accurately controlled by the number of atomic depositions, thereby achieving a more uniform and complete coating.

[0098] Therefore, the composite lithium supplement material prepared by the above preparation method has high electrical conductivity, ion conductivity and air stability, and can effectively improve the lithium supplement effect.

[0099] In one embodiment, in step 1), the sintering temperature is 400°C to 1000°C and the sintering time is 2 hours to 16 hours. Within this range, the coating of the first coating layer and the doping of chlorine into the carbon material and the lithium-rich lithium-supplementing material are facilitated.

[0100] Illustratively, the sintering temperature is 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, or a range consisting of any two of these values; the sintering holding time is 2h, 4h, 6h, 8h, 10h, 12h, 14h or 16h, or a range consisting of any two of these values.

[0101] In a specific embodiment, the reaction temperature in the atomic deposition apparatus is 25° C. to 400° C. Within this range, not only can the uniformity and consistency of the second coating layer be improved, but also energy consumption can be reduced.

[0102] Illustratively, the reaction temperature can be 25°C, 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C or 400°C, or a range consisting of any two of these values.

[0103] In a specific embodiment, the metal oxide source includes a first metal source and an oxygen source; the first metal source includes Al(NEt2)3, Al(NMe2)3, Al(OEt)3, AlCl3, AlEt3, AlMe2Cl, AlMe2H, AlMe3, Si(OEt)4, Si(OMe)4, Si2Cl6, Si2H6, SiCl2H2, SiCl3H, SiCl4, SiH(NMe2)3, SiH2(NEt2)2, SiH2(NMe2)2, SiH4, Ti(CpMe5)(OMe)3, Ti(EtCp)(NMe2)3, Ti(NEt2)4, Ti(NMe2)3(CpMe ), Ti(NMe2)3(CpN), Ti(NMe2)4, Ti(NMeEt)4, Ti(OEt)4, Ti(OMe)4, TiCl4, TiF4, TiI4, Ni(CpEt)2, Ni(MeCp)2, NiCp2, Zn, Zn(OAc)2, ZnCl2, ZnEt2, Z nMe2, Ga2(NMe2)6, GaEt3, GaMe3, Y(CpBu)3, Y(CpEt)3, Y(CpMe)3, YCp3, Zr(Cp2CMe2)Me(OMe), Zr(Cp2CMe2)Me2, Zr(CpEt)(NMe2)3, Zr(CpMe)(NMe2 )3. Zr(CpMe)2Me(OMe), Zr(CpMe)2Me2, Zr(NEt2)4, Zr(NEtMe)4, Zr(NMe2)4, ZrCl4, ZrCp(NMe2)3, ZrCp2Cl2, ZrCp2Me(OMe), ZrCp2Me2, ZrI4, Nb(OE t)5, In(PrNMe2)Me2, InCl3, InEt3, InMe3, InMe3(NMe2Bu), Sn(NEtMe)4, Sn(NMe2)4, SnCl4, SnEt4, SnI4, SnMe4, Hf(Cp)(NMe2)3, Hf(Cp2CMe2)Me(O Me), Hf(Cp2CMe2)Me2, Hf(CpMe)(NMe2)3, Hf(CpMe)2(OMe)Me, Hf(CpMe)2Me2, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Hf(ONEt2)4, HfCl4, HfCp2Cl2, HfCp2Me2, HfI4, Ta(NEt)(NEt2)3, Ta(NEt2)5, Ta(NMe2)5, Ta(OEt)5, TaCl5, TaF5, TaI5; the oxygen source includes at least one of O2, O3, H2O, H2O2, N2O, N2O4, MeOH, and EtOH.

[0104] The present invention does not specifically limit the sources of the first metal source and the oxygen source; commercially available products or products prepared by conventional preparation methods well known to those skilled in the art may be used.

[0105] In a specific embodiment, the metal nitride source includes a second metal source and a nitrogen source; the second metal source includes Al(NEt2)3, Al(NMe2)3, AlCl3, AlEt3, AlH2(NMe2), AlMe3, Ti(NEt2)4, Ti(NEtMe)4, Ti(NMe2)4, TiCl4, TiI4, CoCp2, Ga, GaCl3, GaEt3, GaMe3, Zn(NMe2)4, Zr(NEt2)4, Zr(NEtMe4), At least one of Zr(NMe2)4, ZrCp2(NMe2)2, NbCl5, MoCl5, In, InEtMe2, InMe3, Hf(Cp)(NMe2)3, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Ta(NEtMe)5, Ta(NMe2)5, TaBr5, TaCl5, TaF5, W2(NMe2)6, and WF6; the nitrogen source includes at least one of NH3, N2H4, N2, and Me2NNH2.

[0106] The present invention does not specifically limit the sources of the second metal source and the nitrogen source; commercially available products or products prepared by conventional preparation methods familiar to those skilled in the art may be used.

[0107] A third aspect of the present invention provides a positive electrode sheet comprising the composite lithium-supplementing material of the first aspect or the composite lithium-supplementing material prepared by the preparation method of the second aspect. Therefore, using the positive electrode sheet in a battery can effectively improve its initial coulombic efficiency.

[0108] The present invention does not specifically limit the structure and composition of the positive electrode sheet. In one embodiment, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer arranged on at least a portion of the surface of the positive electrode current collector. The positive electrode active layer includes a positive electrode active material and the composite lithium supplement material of the first aspect.

[0109] The present invention does not impose any specific limitation on the positive electrode current collector, which can be any conventional choice in the art, such as aluminum foil or nickel foil.

[0110] The present invention does not impose specific limitations on the positive electrode active material. It can be any of the positive electrode active materials commonly used in lithium-ion batteries, such as at least one composite oxide of lithium and a metal selected from the group consisting of cobalt, manganese, nickel, and combinations thereof. Specifically, it can be at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium iron phosphate (LFP), lithium nickel manganese oxide, and lithium-rich manganese-based materials.

[0111] It is understood that the positive electrode active layer also includes a binder and a conductive agent, which can be those commonly used in lithium-ion batteries. The conductive agent can be selected from at least one of carbon black, acetylene black, graphene, Ketjen black, and carbon fiber; and the binder can be selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyethylene, polypropylene, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polymers containing ethylene oxide, polyvinyl pyrrolidone, and polyurethane.

[0112] The present invention does not impose any specific restrictions on the ratio of the components in the positive electrode active layer, and a suitable ratio can be selected according to actual conditions.

[0113] The present invention does not specifically limit the preparation method of the positive electrode sheet. In one embodiment, the positive electrode sheet can be prepared by the following method:

[0114] The composite lithium supplement material, positive electrode active material, conductive agent and binder of the present invention are dispersed in an appropriate amount of N-methylpyrrolidone (NMP) solvent, and fully stirred and mixed to form a uniform positive electrode slurry; the positive electrode slurry is evenly coated on the positive electrode current collector, and the positive electrode sheet is obtained after drying, rolling and slitting.

[0115] A fourth aspect of the present invention provides a battery comprising the composite lithium-supplementing material of the first aspect, or the composite lithium-supplementing material prepared by the preparation method of the second aspect, or the positive electrode sheet of the third aspect. Thus, the battery has a high first coulombic efficiency.

[0116] It can be understood that in addition to the above-mentioned positive electrode sheet, the lithium-ion battery also includes a negative electrode sheet, an electrolyte and a separator.

[0117] The present invention does not specifically limit the composition and structure of the negative electrode sheet. In one embodiment, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least a portion of the surface of the negative electrode current collector, and the negative electrode active layer includes a negative electrode active material.

[0118] The present invention does not impose any specific limitation on the negative electrode current collector, which may be any conventional choice in the art, such as copper foil, nickel foam, or copper foam.

[0119] The present invention does not impose any particular limitation on the specific type of negative electrode active material, and it can be at least one of the negative electrode active materials commonly used in lithium-ion batteries, such as graphite, hard carbon, soft carbon, mesophase carbon microbeads, silicon-based negative electrode materials (mainly including silicon monoxide, silicon-carbon negative electrode), tin-based negative electrode materials (mainly including tin, tin alloys), etc.

[0120] It is conceivable that the negative electrode active layer also includes a binder and a conductive agent, which can be the binders and conductive agents commonly used in lithium-ion batteries. For example, the conductive agent can be selected from at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, and graphene. The binder can be selected from at least one of carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyvinyl alcohol, and sodium polyacrylate.

[0121] The present invention does not impose any specific restrictions on the ratio of the components in the negative electrode active layer, and a suitable ratio can be selected according to actual conditions.

[0122] The present invention does not specifically limit the preparation method of the negative electrode sheet. In one embodiment, the negative electrode sheet can be prepared by the following method:

[0123] The negative electrode active material, conductive agent and binder are dispersed in an appropriate amount of deionized water and fully stirred to form a uniform negative electrode slurry; the negative electrode slurry is evenly coated on the negative electrode collector, and the negative electrode sheet is obtained after drying, rolling and cutting.

[0124] The present invention does not specifically limit the composition of the electrolyte, and may include one or more solvents commonly used in lithium-ion battery electrolytes, as well as electrolyte lithium salts commonly used in lithium-ion electrolytes. For example, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), difluoroethylene carbonate (DFEC), dipropyl carbonate, ethyl methyl carbonate (EMC), ethyl acetate, ethyl propionate, propyl acetate, propyl propionate, sulfolane, and γ-butyrolactone; and the lithium salt may be selected from at least one of lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI).

[0125] The present invention does not impose any specific restrictions on the material selection of the diaphragm, and it can be any diaphragm material commonly used in lithium-ion batteries; for example, it can be selected from polypropylene diaphragm (PP), polyethylene diaphragm (PE), polypropylene / polyethylene double-layer composite film (PP / PE), polyimide electrospun diaphragm (PI), polypropylene / polyethylene / polypropylene three-layer composite film (PP / PE / PP), cellulose non-woven fabric diaphragm, and any one of diaphragms with ceramic coating.

[0126] The present invention does not specifically limit the preparation method of the lithium ion battery, and it can be prepared by conventional methods in the art; in one embodiment, it can be prepared by the following method:

[0127] The positive electrode sheet, separator and negative electrode sheet are wound or stacked to obtain a bare battery cell, and the bare battery cell is packaged in a pre-stamped aluminum-plastic film bag; after the packaged battery is dried to remove moisture, the electrolyte is injected into the dry battery, and the battery is shelved, formed and sealed for the second time to complete the preparation of the lithium-ion battery.

[0128] A fifth aspect of the present invention provides a battery pack comprising at least two batteries according to the fourth aspect. The battery pack has the same effects as the batteries described above, which will not be described in detail here.

[0129] It should be noted that the battery cells constituting the battery pack may be electrically connected by conventional methods in the art, such as series connection, parallel connection, or a combination of these connection methods, and there is no particular limitation thereto.

[0130] A sixth aspect of the present invention provides an electrical device, which includes the battery of the fourth aspect or the battery pack of the fifth aspect, so that the electrical device has a longer service life.

[0131] In the present invention, there are no particular limitations on the electrical devices that utilize the above-described batteries or battery packs. For example, such devices include, but are not limited to, mobile phones, laptops, tablet computers, cameras, televisions, radios, wearable devices (such as smart watches, smart bracelets, stereo headsets, Bluetooth headsets), electric vehicles (such as new energy vehicles and electric bicycles), electric toys, backup power supplies, and large household batteries.

[0132] Hereinafter, the composite lithium-supplementing material and the battery comprising the composite lithium-supplementing material provided by the present invention will be described in detail through specific examples.

[0133] Example 1

[0134] 1) Li5FeO4 material powder (particle size D99: 22 μm) and polyvinyl chloride (number average molecular weight: 40,000) were mixed at a mass ratio of 20:1. After the mixture was evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 500°C at a heating rate of 10°C / min, sintered at this temperature for 6 hours, and then cooled naturally to obtain a coated product.

[0135] 2) Place the coated product into a reaction chamber of an atomic layer deposition apparatus pre-filled with dry air, quickly evacuate the chamber, and increase the temperature of the chamber at a rate of 10°C / min to maintain the chamber temperature at 300°C.

[0136] 3) TiCl4 was introduced into the reaction chamber for 5 seconds, and then argon was introduced into the reaction chamber for 30 seconds to purge the reaction chamber to remove excess TiCl4;

[0137] 4) Then, N2H4 was introduced into the reaction chamber for 7 seconds, and then argon was introduced into the reaction chamber for 25 seconds to purge the reaction chamber and remove excess N2H4;

[0138] 5) Repeat steps 3) and 4) thirty times to obtain the composite lithium supplement material of this embodiment;

[0139] TEM testing showed that the thickness of the first coating layer in the composite lithium-supplementing material was 0.18 μm, and the thickness of the second coating layer TiN layer was 3 nm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 22.37 μm; ICP testing showed that the mass content of chlorine in the composite lithium-supplementing material was 27047 ppm.

[0140] Example 2

[0141] 1) Li5FeO4 material powder (particle size D99: 12 μm) and polypropylene chloride (number average molecular weight: 80,000) were mixed at a mass ratio of 100:1. After the mixture was evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 600°C at a heating rate of 5°C / min, sintered at this temperature for 8 hours, and then cooled naturally to obtain a coated product.

[0142] 2) Place the coated product into a reaction chamber of an atomic layer deposition apparatus pre-filled with dry air, quickly evacuate the chamber, and increase the temperature of the chamber at a rate of 8°C / min to maintain the chamber temperature at 250°C.

[0143] 3) AlMe3 was introduced into the reaction chamber for 12 seconds, and then nitrogen was introduced into the reaction chamber for 15 seconds to purge the reaction chamber to remove excess AlMe3;

[0144] 4) NH3 was then introduced into the reaction chamber for 9 seconds, followed by nitrogen purge for 20 seconds to remove excess NH3.

[0145] 5) Repeat steps 3) and 4) ten times to obtain the composite lithium supplement material of this embodiment;

[0146] TEM testing showed that the thickness of the first coating layer in the composite lithium-replenishing material was 0.02 μm, and the thickness of the second coating layer TiN layer was 1 nm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-replenishing material was 12.04 μm; ICP testing showed that the mass content of chlorine in the composite lithium-replenishing material was 4594 ppm.

[0147] Example 3

[0148] 1) Li5FeO4 material powder (particle size D99: 18 μm) and polychloroprene (number average molecular weight: 200,000) were mixed at a mass ratio of 50:1. After the mixture was evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 700°C at a heating rate of 7°C / min, sintered at this temperature for 3 hours, and then cooled naturally to obtain a coated product.

[0149] 2) Place the coated product into the reaction chamber of an atomic layer deposition apparatus pre-filled with dry air, quickly evacuate the chamber, and increase the temperature of the chamber at a rate of 6°C / min to maintain the chamber temperature at 80°C.

[0150] 3) SiCl2H2 was introduced into the reaction chamber for 13 seconds, and then nitrogen was introduced into the reaction chamber for 20 seconds to purge the reaction chamber to remove excess SiCl2H2;

[0151] 4) O3 is then introduced into the reaction chamber for 6 seconds, followed by nitrogen purge for 25 seconds to remove excess O3.

[0152] 5) Repeat steps 3) and 4) ninety times to obtain the composite lithium supplement material of this embodiment;

[0153] TEM testing showed that the thickness of the first coating layer in the composite lithium-replenishing material was 0.06 μm, and the thickness of the second coating layer TiN layer was 9 nm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-replenishing material was 18.14 μm; ICP testing showed that the mass content of chlorine in the composite lithium-replenishing material was 11137 ppm.

[0154] Example 4

[0155] 1) Li5FeO4 material powder (particle size D99: 19 μm) and polyvinylidene chloride (number average molecular weight: 130,000) were mixed at a mass ratio of 140:1. After uniform mixing, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 550°C at a heating rate of 8°C / min, sintered at this temperature for 12 hours, and then cooled naturally to obtain a coated product.

[0156] 2) Place the coated product into the reaction chamber of an atomic layer deposition apparatus pre-filled with dry air, quickly evacuate the chamber, and increase the temperature of the chamber at a rate of 9°C / min to maintain the chamber temperature at 170°C.

[0157] 3) Hf(NMe2)4 was introduced into the reaction chamber for 7 seconds, and then nitrogen was introduced into the reaction chamber for 10 seconds to purge the reaction chamber to remove excess Hf(NMe2)4;

[0158] 4) O3 is then introduced into the reaction chamber for 8 seconds, followed by nitrogen purge for 20 seconds to remove excess O3.

[0159] 5) Finally, H2O was introduced into the reaction chamber for 11 seconds, followed by nitrogen purge for 15 seconds to remove excess H2O.

[0160] 6) Repeat steps 3) and 4) fifty times to obtain the composite lithium supplement material of this embodiment;

[0161] TEM testing showed that the thickness of the first coating layer in the composite lithium-supplementing material was 0.02 μm, and the thickness of the second coating layer TiN layer was 5 nm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 19.06 μm; ICP testing showed that the mass content of chlorine in the composite lithium-supplementing material was 5191 ppm.

[0162] Example 5

[0163] The preparation method of the composite lithium-supplementing material in this embodiment is basically the same as that in Example 1, except that the mass ratio of Li5FeO4 material powder to polyvinyl chloride is 400:1; the thickness of the first coating layer in the composite lithium-supplementing material in this embodiment is 0.009 μm, and the particle size D99 is 22.02 μm; and ICP testing shows that the mass content of chlorine in the composite lithium-supplementing material is 1416 ppm.

[0164] Example 6

[0165] The preparation method of the composite lithium-supplementing material in this embodiment is basically the same as that in Example 1, except that the mass ratio of Li5FeO4 material powder to polyvinyl chloride is 7:1; the thickness of the first coating layer in the composite lithium-supplementing material in this embodiment is 0.50 μm, and the particle size D99 is 23.01 μm; and the ICP test shows that the mass content of chlorine element in the composite lithium-supplementing material is 71000.

[0166] Example 7

[0167] The preparation method of the composite lithium-supplementing material in this embodiment is basically the same as that in Example 1, except that the composite lithium-supplementing material of this embodiment is obtained after repeating steps 3) and 4) one hundred and fifty times; the thickness of the second coating layer in the composite lithium-supplementing material is 15 nm, and the particle size D99 is 22.39 μm; and ICP testing shows that the mass content of chlorine in the composite lithium-supplementing material is 27010 ppm.

[0168] Example 8

[0169] The preparation method of the composite lithium-supplementing material in this embodiment is basically the same as that in Example 1, except that the particle size D99 of the Li5FeO4 material powder is 30 μm; the particle size D99 of the prepared composite lithium-supplementing material is 30.50 μm; and the ICP test shows that the mass content of chlorine in the composite lithium-supplementing material is 26988 ppm.

[0170] Example 9

[0171] The preparation method of the composite lithium-replenishing material in this embodiment is basically the same as that in Example 1, except that the Li5FeO4 material is replaced by Li2NiO2 material, and the particle size D99 is 23 μm; the thickness of the first coating layer of the prepared composite lithium-replenishing material is 0.19 μm, and the thickness of the second coating layer TiN layer is 3 nm; the particle size D99 of the composite lithium-replenishing material is 22.38 μm as measured by a laser particle size analyzer; and the mass content of chlorine in the composite lithium-replenishing material is 27065 ppm as measured by ICP testing.

[0172] Comparative Example 1

[0173] The preparation method of the composite lithium supplement material in this comparative example is basically the same as that in Example 1, except that the Li5FeO4 material powder in this comparative example is not subjected to any coating treatment.

[0174] Comparative Example 2

[0175] Li5FeO4 material powder (particle size D99: 22 μm) and carbon nanotubes were mixed in a mass ratio of 20:1, and after being evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 600°C at a heating rate of 10°C / min, sintered at this temperature for 6 hours, and then cooled naturally to obtain the composite lithium supplement material of this comparative example.

[0176] TEM testing showed that the thickness of the first coating layer in the composite lithium-supplementing material was 0.18 μm; and laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 22.36 μm.

[0177] Comparative Example 3

[0178] 1) Li5FeO4 material powder (particle size D99: 22 μm) and polyvinyl chloride (number average molecular weight: 40,000) were mixed at a mass ratio of 20:1. After the mixture was evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 500°C at a heating rate of 10°C / min, sintered at this temperature for 6 hours, and then cooled naturally to obtain a coated product.

[0179] 2) The coated product was mixed evenly with titanium powder at a mass ratio of 500:1, placed in a sintering furnace reaction chamber, and the temperature of the reaction chamber was raised to 1000°C at a heating rate of 10°C / min. The mixture was sintered under a nitrogen atmosphere for 2 hours to obtain the composite lithium supplement material of this comparative example;

[0180] TEM testing showed that the thickness of the first coating layer in the composite lithium-replenishing material was 0.18 μm, and the thickness of the second coating layer TiN layer was 19 nm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-replenishing material was 22.40 μm; ICP testing showed that the mass content of chlorine in the composite lithium-replenishing material was 26996 ppm.

[0181] Comparative Example 4

[0182] Li5FeO4 material powder (particle size D99: 22 μm) and polyvinyl chloride (number average molecular weight: 40,000) were mixed at a mass ratio of 20:1, and after being evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 500°C at a heating rate of 10°C / min, sintered at this temperature for 6 hours, and then cooled naturally to obtain the composite lithium supplement material of this comparative example.

[0183] TEM testing showed that the thickness of the first coating layer in the composite lithium-supplementing material was 0.18 μm; laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 22.36 μm; and ICP testing showed that the mass content of chlorine in the composite lithium-supplementing material was 27133 ppm.

[0184] Comparative Example 5

[0185] 1) Li5FeO4 material powder (particle size D99: 22 μm) was placed in the reaction chamber of an atomic layer deposition apparatus pre-filled with dry air. The chamber was quickly evacuated and the temperature was increased at a rate of 10°C / min to maintain the chamber temperature at 300°C.

[0186] 2) TiCl4 was introduced into the reaction chamber for 5 seconds, and then argon was introduced into the reaction chamber for 30 seconds to purge the reaction chamber to remove excess TiCl4;

[0187] 3) Then, N2H4 was introduced into the reaction chamber for 7 seconds, and then argon was introduced into the reaction chamber for 25 seconds to purge the reaction chamber and remove excess N2H4;

[0188] 4) Repeating steps 2) and 3) thirty times, thereby obtaining the composite lithium supplement material of this comparative example;

[0189] TEM testing showed that the thickness of the first coating layer TiN layer in the composite lithium-supplementing material was 3 nm; and laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 22.00 μm.

[0190] Comparative Example 6

[0191] 1) Li5FeO4 material powder (particle size D99: 22 μm) and polyethylene (number average molecular weight: 40,000) were mixed at a mass ratio of 20:1. After the mixture was evenly mixed, the mixture was placed in a sintering furnace reaction chamber, and the furnace was quickly evacuated. The reaction chamber was heated to 500°C at a heating rate of 10°C / min, sintered at this temperature for 6 hours, and then cooled naturally to obtain a coated product.

[0192] 2) Place the coated product into a reaction chamber of an atomic layer deposition apparatus pre-filled with dry air, quickly evacuate the chamber, and increase the temperature of the chamber at a rate of 10°C / min to maintain the chamber temperature at 300°C.

[0193] 3) TiCl4 was introduced into the reaction chamber for 5 seconds, and then argon was introduced into the reaction chamber for 30 seconds to purge the reaction chamber to remove excess TiCl4;

[0194] 4) Then, N2H4 was introduced into the reaction chamber for 7 seconds, and then argon was introduced into the reaction chamber for 25 seconds to purge the reaction chamber and remove excess N2H4;

[0195] 5) Repeat steps 3) and 4) thirty times to obtain the composite lithium supplement material of this comparative example;

[0196] TEM testing showed that the thickness of the first coating layer in the composite lithium-supplementing material was 0.18 μm, and the thickness of the second coating layer TiN layer was 3 nm. Laser particle size analyzer testing showed that the particle size D99 of the composite lithium-supplementing material was 22.37 μm.

[0197] Test example

[0198] 1. The composite lithium supplement material prepared in the above embodiment and comparative example is applied to a battery, and the initial charge specific capacity and the initial discharge specific capacity of the battery are tested, specifically comprising the following steps:

[0199] The composite lithium supplement materials prepared in the above examples and comparative examples were divided into two groups, wherein the first group was exposed to air at a temperature of 25° C. and a humidity of 40% for 24 hours, and the other group was not subjected to any treatment.

[0200] The above two groups of composite lithium supplement materials were used as positive electrode active materials to prepare button batteries, including the following steps: dispersing the composite lithium supplement material, conductive carbon black, and polyvinylidene fluoride in N-methylpyrrolidone at a mass ratio of 8:1:1, and uniformly mixing to obtain a positive electrode active slurry; coating the prepared positive electrode active slurry on one side of an aluminum foil, and drying and rolling to obtain a positive electrode sheet with a surface density of 15g / m 2 , compacted density is 3g / cm 3 A lithium metal sheet was used as the negative electrode, a Celgard 2400 polypropylene film was used as the separator, and a mixed solution of ethylene carbonate and dimethyl carbonate (volume ratio of 1:1) containing 1 mol / L lithium hexafluorophosphate was used as the electrolyte. The battery was assembled in an argon-filled glove box with the prepared positive electrode sheet.

[0201] Testing the initial charge specific capacity and initial discharge specific capacity of the button battery prepared above comprises the following steps:

[0202] The LAND battery test system was used with a charge cut-off voltage of 4.5 V, a discharge cut-off voltage of 2.0 V, and a charge and discharge rate of 0.1 C. The first charge specific capacity and first discharge specific capacity of the battery were recorded respectively. The test results are shown in Table 1.

[0203] Table 1

[0204]

[0205] From Table 1 we can see that:

[0206] Compared to Comparative Examples 1 through 6, Examples 1 through 9 all exhibited higher initial charge specific capacities. Specifically, the battery prepared from the composite lithium-supplementing material prepared in Example 1 (unexposed) exhibited an initial charge specific capacity that was 654.6 mAh / g higher. The battery prepared from the exposed composite lithium-supplementing material maintained an initial charge specific capacity of 648.1 mAh / g, a change of only 6.5 mAh / g. This demonstrates that the composite lithium-supplementing material of the present invention exhibits high electrical conductivity and air stability.

[0207] The battery prepared from the composite lithium-supplementing material (unexposed) prepared in Example 9 exhibited a lower initial charge specific capacity. This is primarily due to the Li₂NiO₂ core of the composite lithium-supplementing material, which inherently has a low capacity. However, as shown in Table 1, the initial charge specific capacity of the battery prepared from the exposed composite lithium-supplementing material differed by only 3.3 mAh / g compared to the unexposed composite lithium-supplementing material.

[0208] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite lithium supplement material, characterized in that: The lithium supplement material includes a core, a first coating layer and a second coating layer, wherein the first coating layer is disposed on at least a portion of the surface of the core, and the second coating layer is disposed on at least a portion of the surface of the first coating layer, or at least a portion of the surface of the first coating layer and at least a portion of the surface of the core; The core includes a lithium-rich lithium-supplementing material doped with chlorine, the first coating layer includes a carbon material doped with chlorine, and the second coating layer includes a metal oxide and / or a metal nitride.

2. The composite lithium supplement material according to claim 1, characterized in that The carbon material doped with chlorine is obtained by carbonizing a raw material including a chlorine-containing organic polymer; preferably, the temperature of the carbonization treatment is 400° C. to 1000° C., and the time of the carbonization treatment is 2 h to 16 h.

3. The composite lithium supplement material according to claim 2, characterized in that The chlorine-containing organic polymer includes at least one of polyvinyl chloride, polypropylene chloride, polychloroprene, polyvinylidene chloride, chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and chlorosulfonated polyethylene.

4. The composite lithium supplement material according to any one of claims 1 to 3, characterized in that: The lithium-rich lithium-supplementing material includes Li5FeO4 and / or Li2NiO2.

5. The composite lithium supplement material according to any one of claims 1 to 4, characterized in that: The metal oxide includes at least one of Al2O3, SiO2, TiO2, NiO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, In2O3, SnO2, HfO2, and Ta2O5; and / or the metal nitride includes at least one of AlN, TiN, CoN, GaN, ZrN, NbN, MoN, InN, HfN, TaN, and WN.

6. The composite lithium supplement material according to any one of claims 1 to 5, characterized in that: The thickness of the first coating layer is 0.01 μm to 1 μm, and / or the thickness of the second coating layer is 0.1 nm to 10 nm.

7. The lithium supplement material according to any one of claims 1 to 6, characterized in that: The mass content of chlorine element in the composite lithium supplement material is 1000ppm~70000ppm.

8. The composite lithium supplement material according to any one of claims 1 to 7, characterized in that: The particle size D99 of the composite lithium supplement material is 1 μm to 30 μm.

9. A method for preparing the composite lithium supplement material according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Sintering a raw material comprising a lithium-rich lithium-supplementing material and a chlorine-containing organic polymer to obtain a coated product; The coated product includes a core and a first coating layer coated on at least a portion of the surface of the core, the core includes a lithium-rich lithium-supplementing material doped with chlorine, and the first coating layer includes a carbon material doped with chlorine; 2) placing the coated product into an atomic deposition device, introducing a metal oxide source and / or a metal nitride source into the atomic deposition device for reaction, and depositing a second coating layer on the surface of the coated product to obtain the composite lithium supplement material.

10. The method for preparing the composite lithium supplement material according to claim 9, characterized in that: In step 1), the sintering temperature is 400° C. to 1000° C., and the sintering time is 2 h to 16 h; and / or, in step 2), the reaction temperature in the atomic deposition device is 25° C. to 400° C.

11. The method for preparing a composite lithium supplement material according to claim 9 or 10, characterized in that: The metal oxide source includes a first metal source and an oxygen source; the first metal source includes Al(NEt2)3, Al(NMe2)3, Al(OEt)3, AlCl3, AlEt3, AlMe2Cl, AlMe2H, AlMe3, Si(OEt)4, Si(OMe)4, Si2Cl6, Si2H6, SiCl2H2, SiCl3H, SiCl4, SiH(NMe2)3, SiH2(NEt2)2, SiH2(NMe2)2, SiH4, Ti(CpMe5)(OMe)3, Ti(EtCp)(NMe2)3, Ti(NEt2)4, Ti(NMe2)3(CpMe), Ti(N Me2)3(CpN), Ti(NMe2)4, Ti(NMeEt)4, Ti(OEt)4, Ti(OMe)4, TiCl4, TiF4, TiI4, Ni(CpEt)2, Ni(MeCp)2, NiCp2, Zn, Zn(OAc)2, ZnCl2, ZnEt2, ZnMe2, Ga2(NMe2)6, GaEt3, GaMe3, Y(CpBu)3, Y(CpEt)3, Y(CpMe)3, YCp3, Zr(Cp2CMe2)Me(OMe), Zr(Cp2CMe2)Me2, Zr(CpEt)(NMe2)3, Zr(CpMe)(NMe2)3, Zr (CpMe)2Me(OMe), Zr(CpMe)2Me2, Zr(NEt2)4, Zr(NEtMe)4, Zr(NMe2)4, ZrCl4, ZrCp(NMe2)3, ZrCp2Cl2, ZrCp2Me(OMe), ZrCp2Me2, ZrI4, Nb(OEt)5, In(PrNMe2)Me2, InCl3, InEt3, InMe3, InMe3(NMe2Bu), Sn(NEtMe)4, Sn(NMe2)4, SnCl4, SnEt4, SnI4, SnMe4, Hf(Cp)(NMe2)3, Hf(Cp2CMe2)Me(OMe) , Hf(Cp2CMe2)Me2, Hf(CpMe)(NMe2)3, Hf(CpMe)2(OMe)Me, Hf(CpMe)2Me2, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Hf(ONEt2)4, HfCl4, HfCp2Cl2, HfCp2Me2, HfI4, Ta(NEt)(NEt2)3, Ta(NEt2)5, Ta(NMe2)5, Ta(OEt)5, TaCl5, TaF5, TaI5; the oxygen source includes at least one of O2, O3, H2O, H2O2, N2O, N2O4, MeOH, and EtOH.

12. The method for preparing a composite lithium supplement material according to any one of claims 9 to 11, characterized in that: The metal nitride source includes a second metal source and a nitrogen source; the second metal source includes Al(NEt2)3, Al(NMe2)3, AlCl3, AlEt3, AlH2(NMe2), AlMe3, Ti(NEt2)4, Ti(NEtMe)4, Ti(NMe2)4, TiCl4, TiI4, CoCp2, Ga, GaCl3, GaEt3, GaMe3, Zn(NMe2)4, Zr(NEt2)4, Zr(NEtMe)4, Zr(NM e2)4, ZrCp2(NMe2)2, NbCl5, MoCl5, In, InEtMe2, InMe3, Hf(Cp)(NMe2)3, Hf(NEt2)4, Hf(NEtMe)4, Hf(NMe2)4, Ta(NEtMe)5, Ta(NMe2)5, TaBr5, TaCl5, TaF5, W2(NMe2)6, WF6; the nitrogen source includes at least one of NH3, N2H4, N2, Me2NNH2.

13. A positive electrode sheet, characterized in that: The positive electrode sheet comprises the composite lithium-supplementing material according to any one of claims 1 to 8, or the composite lithium-supplementing material prepared by the preparation method according to any one of claims 9 to 12.

14. A battery, characterized in that: The battery comprises the composite lithium-supplementing material according to any one of claims 1 to 8, or the composite lithium-supplementing material prepared by the preparation method according to any one of claims 9 to 12, or the positive electrode sheet according to claim 13.

15. A battery pack, characterized in that: The battery pack comprises at least two batteries according to claim 14.

16. An electrical device, characterized in that: The electrical device includes the battery according to claim 14 or the battery pack according to claim 15.

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