Ionically electronically conductive conductor and method of making same, and electrode material and method of making same

Abstract

The application provides an ion-electron composite conductor and a preparation method thereof, an electrode material and a method for preparing the electrode material, relates to the technical field of batteries, and the nano titanium aluminum lithium phosphate-nano carbon ion-electron composite conductor comprises titanium aluminum lithium phosphate nanoparticles and nano carbon material which is compounded with the titanium aluminum lithium phosphate nanoparticles; the titanium aluminum lithium phosphate comprises lithium elements, aluminum elements, titanium elements, oxygen elements and phosphorus elements; wherein the average particle size of primary particles of the nano titanium aluminum lithium phosphate-nano carbon ion-electron composite conductor is 30-100 nm. The application can be directly applied to surface coating treatment of electrode materials by obtaining a composite structure with uniform distribution of nano solid-state electrolyte and conductive carbon, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to an ion-electron composite conductor and a preparation method thereof, an electrode material and a method for preparing the same. BACKGROUND

[0002] Lithium ion secondary batteries have been increasingly popular and have been widely used in consumer electronics such as smart phones, tablets, smart watches, and in the fields of power and energy storage. Therefore, it is crucial to develop lithium ion batteries with high energy density and good cycle retention rate. High-voltage lithium cobalt oxide cathodes, high-nickel ternary cathodes, high-voltage spinel lithium nickel manganese oxide cathodes, lithium-rich manganese-based cathodes, and silicon-carbon anodes are widely used as mainstream electrode materials with high energy density.

[0003] However, the above materials usually have the problems of structural instability during electrochemical cycling and accelerated electrolyte decomposition, which leads to rapid capacity decay of the materials, especially at high current, and poor rate performance related to low electrical conductivity.

[0004] Electrode material surface modification, addition of modified materials in electrode slurry, and material morphology and size control are considered to be effective methods to improve the capacity decay of electrode materials during cycling and to improve the safety of batteries.

[0005] Currently, the common modified materials include electrochemically inert materials such as metal oxides, ion conductor materials, electronic conductor materials, and composite materials developed therefrom. Using ion-electron composite conductors with electrochemical activity as modifiers can form a protective layer on the surface of electrode materials, and it is also expected to build effective electron and ion transport channels inside the electrode, further improving the rate performance and stability of the battery. However, the particle size of the ion conductor in the current composite conductor material is usually large (close to or greater than 100 nm) and prone to agglomeration. When mixed with battery active materials, it is difficult to ensure uniform distribution of ion and electronic conductive materials on the surface of electrode materials and inside the electrode, which further makes it difficult to achieve uniform and effective surface coating of electrode materials, and greatly increases the impedance at the electrode interface, resulting in a decrease in battery stability. In addition, the electrode material changes its structure during battery cycling, which easily damages the ion-electron composite conductor structure that is not tightly combined, and thus cannot maintain continuous electron and ion transport channels, affecting the full play of electrochemical performance.

[0006] CN109713235A discloses a kind of conductive ion-conducting composite material and preparation method thereof, the scheme proposes a kind of conductive ion-conducting composite material, including conductive component and ion-conducting component, the conductive component and the ion-conducting component are combined together by chemical bond, the conductive component includes carbon material, the carbon material includes pure phase carbon material or carbon material containing doping element, the ion-conducting component includes fast ion conductor, the conductive ion-conducting composite material simultaneously has electronic channel and ion channel, the electronic channel is coupled with the ion channel.The conductive ion-conducting composite material simultaneously has high electron conduction and high ion conduction performance, and stable structure, when it is applied to the modification treatment of electrode material, the energy density of electrode material itself can be maximized, and the long cycle stability and safety of battery are improved.The scheme also provides the preparation method of the conductive ion-conducting composite material, and the modified electrode material based on the conductive ion-conducting composite material, its preparation method and energy storage device.

[0007] But the above scheme does not mention the particle size of the ion-conducting component in the conductive ion-conducting composite material; the preparation scheme mentions using conductive component and ion-conducting component to synthesize raw materials, or using ion-conducting component and conductive component to prepare raw materials, and using chemical compounding method to prepare conductive ion-conducting composite material, which is complex and difficult to ensure uniformity of component distribution.

[0008] CN119100356A discloses a nano-carbon composite titanium aluminum lithium phosphate conductive functional material, its preparation process and application, the scheme adopts the way of adding synthetic components step by step, so that the reaction is carried out according to the preset selectivity, improves the uniformity of mixing, controls the reaction rate, improves the utilization rate of raw materials, realizes large-scale production application without complex process control, synthesizes in-situ composite carbon layer nano-phosphate titanium aluminum lithium conductive functional material under inert gas, so that it is not limited to the category of being used alone as solid-state electrolyte, carbon composite nano-modification endows electron-insulating titanium aluminum lithium phosphate with higher electronic conductivity, and prepares nano-carbon composite titanium aluminum lithium phosphate conductive functional material and its slurry, which can be used as a modified material of lithium ion battery, solid-state or semi-solid battery electrode material, helps to passivate electrode material surface activity, reduces battery material interface side reaction, slows down material structure degradation in cycle, and is beneficial to enhancing overall safety of lithium ion battery.

[0009] But the scheme in-situ chemically composites each preparation raw material of titanium aluminum lithium phosphate with carbon source to form titanium aluminum lithium phosphate material with carbon layer, which is not conducive to controlling reaction process and uniform dispersion of product, and organic titanium source and organic solvent are used in the process, which is high in cost and poor in safety.

[0010] The lithium titanium aluminum phosphate / carbon composite material mentioned in the above prior art has two main preparation techniques: one part is to directly use lithium titanium aluminum phosphate particles and different carbon sources for physical mixing and dispersion, but (1) if dry mixing and dispersion is used, the sizes of the two materials are small, and uniform mixing and dispersion is difficult to achieve, which may cause excessive local lithium titanium aluminum phosphate coating and insufficient carbon coating when used for positive electrode material surface coating, thereby increasing the interface impedance and reducing the battery performance; if the carbon coating is excessive and the lithium titanium aluminum phosphate coating is insufficient, the lithium titanium aluminum phosphate cannot protect the material surface; (2) if wet mixing is used, the solid electrolyte particle density is higher than that of the nano carbon material, and sedimentation may occur in the solution, so that the distribution of the two in the slurry deviates from the design value, and thus the design ratio is deviated in the subsequent use. Excessive solid electrolyte particles and less conductive carbon coated on the surface of the electrode material may significantly reduce the electronic conductivity; less solid electrolyte particles and more conductive carbon coated on the surface of the electrode material may reduce the ionic conductivity, and the uneven coating deviating from the design may cause uneven coating of the electrode material; if used as an additive in the electrode material, the distribution of the solid electrolyte and the conductive agent in the electrode may also be uneven, which affects the battery performance. (3) Other methods mostly use organic reaction raw materials and organic solvents for in-situ reaction with carbon sources, which has high production cost and involves organic emissions, flammability and explosion, which is not conducive to large-scale production; the prepared material has large primary particle size and is easy to agglomerate and block, and uniform dispersion and mixing of the two nano materials are difficult to achieve.

[0011] Therefore, it is necessary to develop a new product that is more conducive to the combination of lithium titanium aluminum phosphate nano material and carbon nano material. SUMMARY

[0012] In view of the deficiencies of the prior art, the purpose of the present application is to provide an ion-electron composite conductor and a preparation method thereof, an electrode material and a method for preparing the same. The ion-electron composite conductor has uniform distribution of lithium titanium aluminum phosphate particles and nano carbon material in a solid state, and the nano carbon material does not significantly agglomerate under the separation of the lithium titanium aluminum phosphate particles, so that it can be directly applied to the surface coating of the electrode material, and has wide application prospect.

[0013] To achieve this purpose, the present application adopts the following technical solutions:

[0014] In a first aspect, the present application provides a nano-titanium aluminum lithium phosphate-nano-carbon ionic and electronic composite conductor, which comprises titanium aluminum lithium phosphate and nano-carbon material compounded with the titanium aluminum lithium phosphate; the titanium aluminum lithium phosphate comprises lithium, aluminum, titanium, oxygen and phosphorus; the compounding comprises that the titanium aluminum lithium phosphate nanoparticles are tightly combined with the nano-carbon material, and / or the nano-carbon material forms a coating layer on the surface of the titanium aluminum lithium phosphate.

[0015] The average particle size of the primary particles of the nano-titanium aluminum lithium phosphate-nano-carbon ionic and electronic composite conductor is 30-100 nm.

[0016] The average particle size of the primary particles of the nano-titanium aluminum lithium phosphate-nano-carbon ionic and electronic composite conductor is 30-100 nm, for example, 30 nm, 38 nm, 46 nm, 54 nm, 62 nm, 69 nm, 77 nm, 85 nm, 93 nm or 100 nm, but is not limited to the listed values, and other values not listed in this range are also applicable. The nano-titanium aluminum lithium phosphate-nano-carbon ionic and electronic composite conductor provided by the present application comprises lithium ion conductor titanium aluminum lithium phosphate and nano-carbon material, wherein the nano-titanium aluminum lithium phosphate and the nano-carbon material can be uniformly dispersed and interact with each other to provide a continuous and stable ionic and electronic conduction network, which can be used for surface coating of liquid, solid or semi-solid lithium ion battery electrode materials. Taking the positive electrode material as an example, the composite conductor forms a surface coating layer on the positive electrode material, wherein the solid electrolyte part can protect the positive electrode from being eroded by the electrolyte, inhibit the interface side reaction between the positive electrode material and the electrolyte, and reduce the dissolution of transition metals; the uniformly coated electronic conductor structure can provide a good electronic channel for the positive electrode material; this scheme of simultaneously coating the ionic conductor and the electronic conductor layer on the surface of the positive electrode material in one coating can effectively reduce the internal polarization of the battery and effectively improve the surface stability / cycle stability of the positive electrode material.

[0017] Preferably, the molar ratio of lithium, aluminum, titanium and phosphorus in the titanium aluminum lithium phosphate is (1+x):x:(2-x):3, wherein x is 0-0.5, but not including 0, for example, 0.01, 0.02, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45 or 0.5, etc.

[0018] Preferably, the nanoparticles in the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor are dumbbell-shaped and have a porous structure. Moreover, the porous state of the dumbbell-shaped adhesion is easily crushed into primary particles under the mechanical action of the high mixer or fusion machine, and the surface of the positive electrode material is coated, and the carbon material is also uniformly coated on the surface of the positive electrode material, avoiding the process step of pre-selecting the solid electrolyte and carbon material, reducing the cost, and also increasing the uniformity of dispersion., at the same time, the secondary particle size of such material is large, which is also convenient to operate.

[0019] Preferably, the pore volume of the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is >0.1 cm 3 / g, for example, it can be 0.11 cm 3 / g, 0.12 cm 3 / g, 0.13 cm 3 / g, 0.14 cm 3 / g, 0.15 cm 3 / g, 0.16 cm 3 / g, 0.18 cm 3 / g, 0.19 cm 3 / g, 0.2 cm 3 / g, 0.22 cm 3 / g, or 0.25 cm 3 / g, etc., but not limited to the listed values, and other unlisted values within the range are also applicable.

[0020] Preferably, the average pore size of the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is <10 nm, for example, it can be 9.9 nm, 9.8 nm, 9.5 nm, 9.2 nm, 9.0 nm, 8.9 nm, 8.8 nm, 8.7 nm, 8.5 nm, 8.2 nm, 8.0 nm, 7.8 nm, 7.5 nm, 7.0 nm, 6.5 nm, 6.0 nm, 5.5 nm, or 5.0 nm, etc., but not limited to the listed values, and other unlisted values within the range are also applicable.

[0021] Preferably, the specific surface area of the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is 15-300 m 2 / g, for example, it can be 15 m 2 / g, 40 m 2 / g, 69 m 2 / g, 98 m 2 / g, 127 m 2 / g, 156 m 2 / g, 185 m 2 / g, 214 m2 / g, 243m 2 / g, 272m 2 / g or 300m 2 / g, etc., but not limited to the listed values, other unlisted values within the range are also applicable.

[0022] Preferably, the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor has obvious diffraction peaks of LiTi2(PO4)3 in the XRD spectrum, and the diffraction peaks are consistent with the standard PDF # 35-0754.

[0023] Preferably, the carbon content in the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is 1% to 15%, for example, it can be 1%, 2%, 3%, 5%, 8%, 10%, 12%, 14% or 15%, etc., but not limited to the listed values, other unlisted values within the range are also applicable.

[0024] Preferably, the mass ratio of unbound nano-carbon to nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor in the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is 0.005% to 0.069%, for example, it can be 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.06%, 0.062%, 0.065% or 0.069%, etc., but not limited to the listed values, other unlisted values within the range are also applicable.

[0025] The unbound nano-carbon in the present application refers to the nano-carbon that is separated from the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor to the solution after the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is placed in the solution and stirred and dispersed.

[0026] Preferably, the secondary particle size D50 of the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor is 1 to 30 μm, for example, it can be 1 μm, 2 μm, 5 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 28 μm or 30 μm, etc., but not limited to the listed values, other unlisted values within the range are also applicable. In the second aspect, the present application provides a preparation method of the nano-titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor of the first aspect, the preparation method comprises:

[0027] (1) mixing lithium aluminum titanium phosphate precursor particles with a particle size of 5 to 30 nm and water, and dispersing to obtain a lithium aluminum titanium phosphate precursor aqueous slurry; wherein the lithium aluminum titanium phosphate precursor particles comprise lithium element, aluminum element, titanium element, oxygen element, hydrogen element and phosphorus element;

[0028] (2) mixing the carbon source and the titanium aluminum lithium phosphate precursor aqueous slurry, and sequentially stirring, drying and calcining to obtain the nano titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor.

[0029] The preparation method provided by the application mixes the 5-30 nm ultrafine solid-state electrolyte titanium aluminum lithium phosphate precursor particles with water to obtain a high-dispersion titanium aluminum lithium phosphate precursor dispersion slurry, which is mixed with a carbon source as a reaction raw material, so that the two kinds of nano ionic and electronic conductor materials can be uniformly dispersed to obtain a high-dispersion ionic electronic composite conductor aqueous slurry. After being mixed with the carbon source, the slurry is dried and sintered in an inert gas atmosphere such as nitrogen or argon to obtain a nano titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor material in which the titanium aluminum lithium phosphate particles and the nano carbon are uniformly distributed and the mass ratio can be adjusted, and the size of the titanium aluminum lithium phosphate particles is below 100 nm, and even below 50 nm.

[0030] The process method of the application is simple to synthesize and easy to operate, and is beneficial to large-scale production. The small-particle-size titanium aluminum lithium phosphate precursor is used as a raw material, and the ionic electronic composite conductor based on different particle sizes of titanium aluminum lithium phosphate can be obtained by controlling the calcination conditions. Moreover, the titanium aluminum lithium phosphate particles are generated in situ, which helps to stabilize the ionic electronic composite structure, avoids the destruction of the structure under long cycle and high rate of the battery, maintains excellent ionic electronic conductivity, and reduces the impedance at the electrode interface.

[0031] The preparation method of the nano titanium aluminum lithium phosphate-nano carbon ionic electronic composite conductor provided by the application prepares the composite material by mixing and calcining, does not need subsequent wet grinding and dispersion, can obtain a composite structure in which the nano solid-state electrolyte and the conductive carbon are uniformly distributed, and can be directly applied to the surface coating treatment of the positive electrode material. In addition, because the solid-state electrolyte particles and the nano carbon material are combined with each other, they have a stronger combination with the surface of the positive electrode material, are not easy to fall off from the surface of the positive electrode material during the electrode material mixing process, and can form a stable coating.

[0032] The drying in the above process is not particularly limited, and any device and mode that can be used for drying known to those skilled in the art can be used, and the actual process can be adjusted, for example, air drying, vacuum drying, oven drying or freeze drying, or a combination of different modes.

[0033] Preferably, after the calcination, the preparation method further includes appropriate crushing.

[0034] The present application also does not have special restrictions on the crushing in the above process. Any device and method known to those skilled in the art that can be used for crushing can be used, and the actual process can also be adjusted. For example, it can be grinding, extrusion crushing, splitting crushing, or impact crushing, etc. It can also be a combination of different methods.

[0035] Preferably, in the XRD spectrum of the lithium aluminum titanium phosphate precursor particles in step (1), the peak intensity ratio of the first strong diffraction peak and the second strong diffraction peak is 0.5-2.0, for example, it can be 0.5, 0.7, 0.9, 1, 1.2, 1.4, 1.5, 1.7, 1.9 or 2.0, etc. but not limited to the listed values, other values not listed in this range are also applicable, the half-height width of the first strong diffraction peak and the second strong diffraction peak is independently 0.3-0.8°, for example, it can be 0.3°, 0.4°, 0.5°, 0.6°, 0.7° or 0.8°, etc. but not limited to the listed values, other values not listed in this range are also applicable. The peak position of the first strong diffraction peak is in the range of 26.5-27.5°, and the peak position of the second strong diffraction peak is in the range of 27.5-28.5°.

[0036] Preferably, the lithium aluminum titanium phosphate precursor particles use the lithium aluminum titanium phosphate precursor particles described in CN116914237A as the reaction raw material. The precursor particles have small particle size, uniform particle size distribution, and are easy to disperse, which is beneficial to the uniform mixing and high dispersion of nano lithium aluminum titanium phosphate and nano carbon material. In addition, the reaction process is simple and easy to operate, the reaction raw materials are cheap and easy to obtain, and it is suitable for industrial production.

[0037] Preferably, the specific surface area of the lithium aluminum titanium phosphate precursor particles is 60-150m 2 / g, for example, it can be 60m 2 / g, 70m 2 / g, 80m 2 / g, 90m 2 / g, 100m 2 / g, 110m 2 / g, 120m 2 / g, 130m 2 / g, 140m 2 / g, or 150m 2 / g, etc. but not limited to the listed values, other values not listed in this range are also applicable.

[0038] Preferably, the molar ratio of lithium element, aluminum element, titanium element and phosphorus element in the lithium aluminum titanium phosphate precursor particles is (1+x):x:(2-x):3, where x is 0-0.5, but not including 0, for example, it can be 0.1, 0.12, 0.13, 0.15, 0.18, 0.2, 0.22, 0.23, 0.25, 0.28, 0.30, 0.32, 0.33, 0.35, 0.38, 0.40, 0.42, 0.45, 0.48 or 0.5, etc.

[0039] Preferably, in the XRD spectrum of the lithium aluminum titanium phosphate precursor particles, diffraction peaks exist at 2θ of 16.8-17.3°, 18.3-18.9° and 24.5-25.0°, respectively.

[0040] Preferably, the solid content of the lithium aluminum titanium phosphate precursor aqueous slurry in step (1) is 5-30wt%, for example, it can be 5wt%, 8wt%, 11wt%, 14wt%, 17wt%, 19wt%, 22wt%, 25wt%, 28wt% or 30wt%, etc., but is not limited to the listed values, other unlisted values within this range are also applicable.

[0041] Preferably, the dispersion includes any one or a combination of at least two of sand mill dispersion, ball mill dispersion, high-speed shear dispersion or defoamer mixer stirring dispersion, wherein a typical but non-limiting combination is a combination of sand mill dispersion and ball mill dispersion, a combination of high-speed shear dispersion and ball mill dispersion, a combination of sand mill dispersion and high-speed shear dispersion, a combination of defoamer mixer stirring dispersion and ball mill dispersion, a combination of sand mill dispersion and defoamer mixer stirring dispersion.

[0042] Preferably, the carbon source in step (2) includes nano-carbon material and / or organic carbon source.

[0043] Wherein, the nano-carbon material is generally first prepared into an aqueous dispersion slurry, or a commercial conductive carbon slurry is used, wherein the dispersion medium in the conductive carbon slurry is water, and the carbon material is one or more of carbon nanotubes, graphite, graphene, hard carbon, Ketjen black, acetylene black, Super P, vapor grown carbon fiber; the organic carbon source is a water-soluble organic material that can produce carbon under a protective atmosphere such as nitrogen atmosphere, such as one or more of glucose, sucrose or starch, and one or more of polymer dispersants such as styrene maleic acid copolymer solution or modified polyethylene glycol can also be used.

[0044] Preferably, the mass ratio of the lithium aluminum titanium phosphate precursor particles to the carbon element in the carbon source is 18.5:3~114.6:1, for example, it can be 18.5:3, 38.5:3, 19.5:1, 39.5:1, 59.5:1, 79.5:1, 99.5:1 or 114.6:1, etc., but not limited to the listed values, other unlisted values within the range are also applicable. When using nano-carbon materials, the amount used is 1%~15% because nano-carbon does not decompose in the atmosphere; when using organic carbon sources, the amount used is 4.8%~54.1% because the carbon yield after pyrolysis of the general organic carbon source is 15%~20%; in summary, because there are also cases where nano-carbon sources + organic carbon sources are used together. Here, the carbon content in the final product is calculated, and the C: LATP in the finished product is generally 1:99~3:17.

[0045] Preferably, the inorganic carbon source includes a water-based dispersed carbon slurry.

[0046] Preferably, the carbon material in the dispersed carbon slurry includes any one or a combination of at least two of carbon nanotubes, graphite, graphene, hard carbon, Ketjen black, acetylene black, Super P or vapor grown carbon fiber, wherein typical but non-limiting combinations are a combination of carbon nanotubes and graphite, a combination of graphene and graphite, a combination of carbon nanotubes and graphene, a combination of hard carbon and graphite, a combination of carbon nanotubes and hard carbon, a combination of Ketjen black and graphite, a combination of acetylene black and Ketjen black, a combination of Super P and vapor grown carbon fiber.

[0047] Preferably, the organic carbon source includes a water-soluble organic material that can be cracked to produce carbon in a protective atmosphere.

[0048] Preferably, the organic material includes any one or a combination of at least two of glucose, sucrose, starch, styrene maleic acid copolymer or modified polyethylene glycol, wherein typical but non-limiting combinations are a combination of glucose and sucrose, a combination of starch and sucrose, a combination of glucose and starch, a combination of styrene maleic acid copolymer and sucrose, a combination of glucose and styrene maleic acid copolymer, a combination of modified polyethylene glycol and sucrose, a combination of glucose and modified polyethylene glycol.

[0049] The modified polyethylene glycol in the present application can use the modified polyethylene glycol for precursors well known to those skilled in the art, for example, it can be Sinonar LD1280-50W.

[0050] Preferably, the calcination is carried out in a protective atmosphere. Wherein, the protective atmosphere includes a nitrogen and / or argon atmosphere.

[0051] Preferably, the calcination temperature is 400-900℃, for example, it can be 400℃, 456℃, 512℃, 567℃, 623℃, 678℃, 734℃, 789℃, 845℃ or 900℃, etc., but not limited to the listed values, other values in the range not listed are also applicable, preferably 750-900℃; and / or, the calcination time is 1-4h, for example, it can be 1h, 1.4h, 1.7h, 2h, 2.4h, 2.7h, 3h, 3.4h, 3.7h or 4h, etc., but not limited to the listed values, other values in the range not listed are also applicable.

[0052] The application also provides the application of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor of the first aspect, which is applied in the field of batteries, especially in electrodes.

[0053] For example, the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor is used as a surface coating layer of an electrode material.

[0054] In a third aspect, the application provides an electrode material, which comprises an electrode powder and an electrode coating layer coated on the outside of the electrode powder; the material of the electrode coating layer comprises the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor of the first aspect.

[0055] The electrode material provided in the third aspect of the application coats the surface of the electrode powder with the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, which improves the overall performance of the electrode.

[0056] Preferably, the material of the electrode powder comprises any one or a combination of at least two of lithium cobalt oxide, spinel lithium manganate, spinel lithium nickel manganate, ternary material or lithium-rich manganese-based material.

[0057] Preferably, the average particle size of the electrode powder is >2µm, for example, it can be 2.1µm, 2.2µm, 2.3µm, 2.4µm, 2.5µm, 2.6µm, 2.7µm, 2.8µm, 2.9µm, 3.0µm, 3.2µm, 3.5µm, 4.0µm or 4.5µm, etc.

[0058] Preferably, the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor accounts for 0.01-5wt% of the mass of the electrode material, for example, it can be 0.01wt%, 0.57wt%, 1.12wt%, 1.68wt%, 2.23wt%, 2.79wt%, 3.34wt%, 3.9wt%, 4.45wt% or 5wt%, etc., but not limited to the listed values, other values in the range not listed are also applicable.

[0059] The application can mix the nano-phosphor titanium aluminum lithium-carbon ion electronic composite conductor and the lithium ion battery electrode material by using the dry coating process, form a coating layer on the electrode surface, and then perform simple calcination to obtain the electrode material with thin coating layer, which can stabilize the electrode material structure, reduce the electrode / electrolyte interface side reaction, stabilize the uniform ion electronic composite conductor structure, improve the ion and electron conductivity, promote the transfer of ions and electrons, and improve the overall performance of the lithium ion battery.

[0060] In a fourth aspect, the application provides a method for preparing the electrode material of the third aspect, which comprises mixing the electrode powder and the nano-phosphor titanium aluminum lithium-carbon ion electronic composite conductor, and sequentially sintering and cooling to obtain the coated electrode material.

[0061] Preferably, the sintering temperature is 200-600℃, for example, it can be 200℃, 267℃, 334℃, 350℃, 380℃, 400℃, 420℃, 450℃, 467℃, 500℃, 520℃, 534℃, 550℃, 580℃ or 600℃, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable. The sintering time is 1-4h, for example, it can be 1h, 1.4h, 1.7h, 2h, 2.4h, 2.7h, 3h, 3.4h, 3.7h or 4h, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0062] Preferably, the cooling is to room temperature.

[0063] Preferably, in the preparation process of the electrode material, the mixing step is performed in a high-speed mixer or a mechanical fusion machine.

[0064] Compared with the prior art, the application has at least the following beneficial effects:

[0065] (1) The nano-phosphor titanium aluminum lithium-carbon ion electronic composite conductor provided by the application has a particle size of less than 100nm, and even less than 50nm, and the average particle size of the primary particles is 30-100nm, so that a small-size ion electronic composite conductor is obtained.

[0066] (2) The preparation method of the nano-phosphor titanium aluminum lithium-carbon ion electronic composite conductor is simple and easy to operate, and is beneficial to large-scale production. Using small-particle-size phosphor titanium aluminum lithium precursor as raw material, ion electronic composite conductors based on different particle sizes of phosphor titanium aluminum lithium can be obtained by controlling the calcination conditions. Moreover, the phosphor titanium aluminum lithium particles are generated by in-situ reaction, which helps to stabilize the ion electronic composite structure, avoids the destruction of the structure under long cycle and high rate of the battery, maintains excellent ion electronic conductivity, and reduces the impedance at the electrode interface.

[0067] (3) The electrode material provided by the application adopts nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor to coat electrode powder. Since small-size titanium aluminum lithium phosphate particles and nanometer carbon material are uniformly distributed and can form a stable structure of composite, it is helpful to build a continuous and stable ion / electron transmission channel on the electrode surface, thereby promoting the full play of the electrochemical performance of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 Figure 1 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 1 of the application.

[0069] Figure 2 Figure 2 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 1 of the application.

[0070] Figure 3 Figure 3 is an XRD image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 1 of the application.

[0071] Figure 4 Figure 4 is a SEM image of the dry-mixed dry-mixed material in Application Example 1-1 of the application.

[0072] Figure 5 Figure 5 is a SEM image of the material after calcination after dry-mixing in Application Example 1-1 of the application.

[0073] Figure 6 Figure 6 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 2 of the application.

[0074] Figure 7 Figure 7 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 2 of the application.

[0075] Figure 8 Figure 8 is an XRD image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 2 of the application.

[0076] Figure 9 Figure 9 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 3 of the application.

[0077] Figure 10 Figure 10 is a SEM image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 3 of the application.

[0078] Figure 11 Figure 11 is an XRD image of the nanometer titanium aluminum lithium phosphate-nanometer carbon ion-electron composite conductor prepared in Example 3 of the application.

[0079] Figure 12 SEM image of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in Inventive Comparative Example 1.

[0080] Figure 13 XRD image of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in Inventive Comparative Example 1.

[0081] Figure 14 SEM image of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in Inventive Comparative Example 2.

[0082] Figure 15 XRD image of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in Inventive Comparative Example 2. DETAILED DESCRIPTION

[0083] In order to facilitate the understanding of the present application, the present application is illustrated as follows. It should be understood by those skilled in the art that the examples are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0084] Example 1

[0085] The present embodiment provides a preparation method of a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor, which comprises the following steps:

[0086] (1) Lithium titanium aluminum phosphate precursor particles (solid-state electrolyte lithium titanium aluminum phosphate precursor obtained in Example 1 in CN118637585A) with a molar ratio of lithium element, aluminum element, titanium element and phosphorus element of 1.3:0.3:1.7:3 and a primary particle size of 15 nm are used as reaction raw materials. 32 g of lithium titanium aluminum phosphate precursor particles, 288 g of deionized water and zirconium beads with a diameter of 0.1 mm are loaded into a grinding cavity, and then sand grinding is carried out at a speed of 2000 rpm for 1 h. The material liquid and zirconium beads are separated by a suction filtration device, and a uniform and stable lithium titanium aluminum phosphate precursor aqueous slurry with a solid content of 10 wt% is prepared.

[0087] (2) According to the mass ratio of lithium titanium aluminum phosphate precursor particles to carbon nanotubes of 6.5:1, lithium titanium aluminum phosphate precursor aqueous slurry and carbon nanotube slurry (the solvent in the carbon nanotube slurry is water, and the solid content is 4.01 wt%) are weighed and added into a homogenizing emulsifying tank. High-speed stirring is carried out at a speed of 10000 rpm for 20 min to obtain paste-like composite conductor slurry uniformly mixed with lithium titanium aluminum phosphate precursor and carbon nanotubes. The paste-like composite conductor slurry is placed in a vacuum drying box at 90°C and ≤1 kPa for 3 h, and then fully ground by an agate rod. In a tube furnace, nitrogen gas is introduced at 800°C for 2 h to obtain a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor.

[0088] The embodiment also provides the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor prepared by the preparation method, and the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor comprises titanium aluminum lithium phosphate and nano-carbon material compounded with the titanium aluminum lithium phosphate; the titanium aluminum lithium phosphate comprises lithium, aluminum, titanium, oxygen and phosphorus; wherein the average particle size of the primary particles of the titanium aluminum lithium phosphate is 50 nm. Figure 1 and Figure 2 Figure 1 is an SEM image of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor prepared in Embodiment 1. Figure 3 Figure 2 is an XRD spectrum of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor prepared in Embodiment 1.

[0089] The molar ratio of lithium, aluminum, titanium and phosphorus in the titanium aluminum lithium phosphate is 1.3:0.3:1.7:3; the specific surface area of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor is 77 m 2 / g; the XRD spectrum of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor has obvious diffraction peaks of LiTi2(PO4)3, which is consistent with the standard PDF # 35-0754; and the carbon content in the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor is 14%.

[0090] Application Example 1

[0091] The application example provides an electrode material, and a preparation method of the electrode material comprises the following steps: loading lithium cobaltate and the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor prepared in Embodiment 1 into a special mixing tank of a high-speed mixer, wherein the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor accounts for 0.5 wt% of the sum of the mass of the lithium cobaltate and the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, and high-speed mixing is performed at a speed of 2000 rpm for 5 min to obtain a dry mixing material, and an SEM image of the dry mixing material is as shown in Figure 3; and the dry mixing material is calcined at 250 DEG C for 2 h to obtain lithium cobaltate coated with the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, and an SEM image of the lithium cobaltate coated with the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor is as shown in Figure 4. Figure 3 Figure 4

[0092] Embodiment 2

[0093] The embodiment provides a preparation method of a nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, and the preparation method is the same as that in Embodiment 1, except that the mixing of the titanium aluminum lithium phosphate precursor particles and the carbon nanotubes is performed at a mass ratio of 11:1 in step (2).

[0094] ​​The embodiment provides a nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, which is the same as that in the embodiment 1 except that the carbon content is 9wt%.

[0095] Figure 5 and Figure 6 The SEM image and the XRD pattern of the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor prepared in the embodiment are shown in the following.

[0096] Embodiment 3

[0097] The embodiment provides a preparation method of a nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, which comprises the following steps.

[0098] (1) A lithium element, an aluminum element, a titanium element and a phosphorus element are used as reaction raw materials, and the molar ratio of the lithium element, the aluminum element, the titanium element and the phosphorus element is 1.3:0.3:1.7:3, and the primary particle size of a lithium aluminum titanium phosphate precursor particle (a solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment 1 in CN118637585A) is 15 nm; 64 g of the lithium aluminum titanium phosphate precursor particle, 256 g of deionized water and zirconium beads with a diameter of 0.1 mm are loaded into a grinding cavity, and then sand grinding is performed at a speed of 2000 rpm for 1 h; the material liquid and the zirconium beads are separated by using a suction filtration device, and a uniform and stable lithium aluminum titanium phosphate precursor aqueous slurry with a solid content of 20wt% is prepared.

[0099] (2) According to the modification polyethylene glycol accounting for 25% of the mass of the lithium aluminum titanium phosphate precursor particle, the lithium aluminum titanium phosphate precursor aqueous slurry is mixed with a modified polyethylene glycol suspension liquid with a solid content of 50wt% (the modified polyethylene glycol is Xinnuo LD1280-50W), and high-speed mixing is performed, the speed is 2400 rpm, and the mixing time is 5 min, to obtain a composite conductor slurry in which the lithium aluminum titanium phosphate precursor and the modified polyethylene glycol are uniformly mixed. The composite conductor slurry is placed in a rotary evaporator for drying at 70°C for 2 h, and then fully ground by using a jasper rod; in a tube furnace, argon gas is introduced, and the nano-lithium aluminum titanium phosphate-nano-carbon ionic electronic composite conductor is calcined at 900°C for 1 h.

[0100] The embodiment also provides the nano-lithium aluminum titanium phosphate-nano-carbon ionic electronic composite conductor prepared by using the preparation method, the nano-lithium aluminum titanium phosphate-nano-carbon ionic electronic composite conductor comprises lithium aluminum titanium phosphate and a nano-carbon material which is compounded with the lithium aluminum titanium phosphate; and the lithium aluminum titanium phosphate comprises a lithium element, an aluminum element, a titanium element, an oxygen element and a phosphorus element. Figure 7 and Figure 8 The SEM image and the XRD pattern of the nano-lithium aluminum titanium phosphate-nano-carbon ionic electronic composite conductor prepared in the embodiment 3 are shown in the following.

[0101] The molar ratio of lithium element, aluminum element, titanium element and phosphorus element in the lithium aluminum titanium phosphate is 1.3:0.3:1.7:3; the specific surface area of the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor is 42 m 2 / g; the XRD spectrum of the lithium aluminum titanium phosphate has obvious diffraction peaks of LiTi2(PO4)3, which is consistent with the standard PDF # 35-0754; the carbon content in the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor is 5%.

[0102] Embodiment 4

[0103] The embodiment provides a preparation method of a nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor, and the preparation method comprises the following steps:

[0104] (1) The lithium aluminum titanium phosphate precursor particles (solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in embodiment 2 in CN118637585A) with a molar ratio of lithium element, aluminum element, titanium element and phosphorus element of 1.5:0.5:1.5:3 and a primary particle size D50 of 5 nm are used as reaction raw materials, 90g of the lithium aluminum titanium phosphate precursor particles and 210g of deionized water are mixed, and high-speed shearing dispersion is performed, wherein the rotation speed of the high-speed shearing dispersion is 150000r / min, the time is 30min, and a uniform and stable lithium aluminum titanium phosphate precursor aqueous slurry with a solid content of 30wt% is prepared.

[0105] (2) According to the mass ratio of the lithium aluminum titanium phosphate precursor particles to the graphene of 8.5:1, the lithium aluminum titanium phosphate precursor aqueous slurry and the graphene slurry (the solvent in the graphene slurry is water, and the solid content is 5wt%) are weighed and added into a homogenizing emulsifying tank, high-speed stirring is performed at a rotation speed of 9000rpm for 30min, the paste-shaped composite conductor slurry of the lithium aluminum titanium phosphate precursor and the carbon nanotube is obtained. The paste-shaped composite conductor slurry is dried in a vacuum drying box at 95℃ and under a vacuum of ≤1kPa for 2.5h, is fully ground by a jade bar, and is calcined in a tube furnace in an argon atmosphere at 900℃ for 1h, to obtain the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor.

[0106] The embodiment also provides the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor prepared by the preparation method, the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor comprises lithium aluminum titanium phosphate and nano carbon material which is compounded with the lithium aluminum titanium phosphate; the lithium aluminum titanium phosphate comprises lithium element, aluminum element, titanium element, oxygen element and phosphorus element; wherein the particle size of the lithium aluminum titanium phosphate is 30nm.

[0107] The molar ratio of lithium element, aluminum element, titanium element and phosphorus element in the lithium aluminum titanium phosphate is 1.5:0.5:1.5:3; the specific surface area of the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor is 210m2 / g; the XRD spectrum of the lithium aluminum titanium phosphate has obvious diffraction peaks of LiTi2(PO4)3, which is consistent with the standard PDF # 35-0754; the carbon content in the nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor is 11%.

[0108] Example 5

[0109] The embodiment provides a preparation method of a nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor, wherein the preparation method is different from the method in the embodiment 1 in that the step (1) is not performed, and the lithium aluminum titanium phosphate precursor particles and the carbon nanotubes are directly mixed according to a mass ratio of 6.5:1, the slurry of the lithium aluminum titanium phosphate precursor particles and the carbon nanotubes (the solvent in the carbon nanotube slurry is water, and the solid content is 4.01wt%) is added into the inner and outer parts of the homogenizing emulsifying tank, and the rest is the same as the embodiment 1.

[0110] If the lithium aluminum titanium phosphate precursor particles are not pre-dispersed and directly mixed with the carbon nanotube slurry, partial agglomeration may occur, it is difficult to form a uniform composite structure, the continuity of the conductive network is reduced, the electron / ion transmission path is blocked, and the weak interface combination is easy to cause the particles to fall off in the charging and discharging process, and the capacity attenuation is accelerated.

[0111] Example 6

[0112] The embodiment provides a preparation method of a nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor, wherein the preparation method comprises the following steps: the lithium aluminum titanium phosphate precursor particles (the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment 1 in CN118637585A) and the carbon nanotubes are directly mixed according to a mass ratio of 6.5:1, 15% of a dispersant is added, and ball milling is performed at 350r / min for 80min; then the solid-phase mixture is dried in a vacuum drying box at 90℃ and under a vacuum of ≤1kPa for 3h, is fully ground by a jade bar, is calcined in a tube furnace in a nitrogen atmosphere at 800℃ for 2h, and the nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor is obtained.

[0113] The carbon nanotubes are easy to agglomerate, if the stable slurry is not formed by pre-dispersion, direct dry mixing may cause uneven distribution of the carbon nanotubes in the system, local conductive network is missing, and the difference in density between the free lithium aluminum titanium phosphate particles and the carbon nanotubes in the nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor may cause the mixed slurry to be stratified during storage or coating, and the performance is further deteriorated.

[0114] Example 7

[0115] The embodiment provides a preparation method of a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor, wherein, in step (2), the subsequent mixing is performed according to a mass ratio of lithium titanium aluminum phosphate precursor particles to carbon nanotubes of 1:1, and the rest is the same as in the embodiment 1.

[0116] If the mass ratio of the lithium titanium aluminum phosphate precursor particles to the carbon nanotubes is low, that is, the proportion of the nano lithium titanium aluminum phosphate in the nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor is too low, the protection of the nano lithium titanium aluminum phosphate on the electrode is weakened, the electrode / electrolyte interface side reaction is intensified, and the electrode structure stability is difficult to maintain; in addition, an effective ion transmission path cannot be constructed, and the battery failure is accelerated.

[0117] Embodiment 8

[0118] The embodiment provides a preparation method of a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor, wherein, in step (2), the subsequent mixing is performed according to a mass ratio of lithium titanium aluminum phosphate precursor particles to carbon nanotubes of 130:1, and the rest is the same as in the embodiment 1.

[0119] If the mass ratio of the lithium titanium aluminum phosphate precursor particles to the carbon nanotubes is high, that is, the proportion of the nano carbon in the nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor is too low, a continuous electronic conductive network is difficult to form, the electronic transmission path is blocked, and especially under high current density, the battery capacity is easily attenuated, and the rate performance is reduced.

[0120] Embodiment 9

[0121] The embodiment provides a preparation method of a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor, wherein, in step (2), the calcination temperature is 1000 DEG C, and the rest is the same as in the embodiment 1.

[0122] If the calcination temperature is high, the nano lithium titanium aluminum phosphate particle size is large and unevenly distributed, so that the electrode material surface cannot be uniformly and effectively coated.

[0123] Embodiment 10

[0124] The embodiment provides a preparation method of a nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor, wherein, in step (2), the calcination temperature is 300 DEG C, and the rest is the same as in the embodiment 1.

[0125] If the calcination temperature is low, the generated nano lithium titanium aluminum phosphate phase is impure, and the lithium ion conductivity is reduced.

[0126] Comparative example 1

[0127] The comparative example provides a preparation method of a lithium titanium aluminum phosphate-carbon ionic electronic composite conductor, which is the same as that of Example 6 except that the lithium titanium aluminum phosphate precursor particles in step (1) are replaced by lithium titanium aluminum phosphate precursor particles calcined at 800 DEG C for 2h to obtain lithium titanium aluminum phosphate (the particle size of the primary particles after calcination is 80nm).

[0128] Figure 9 and Figure 10 The SEM image and XRD pattern of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in the comparative example are shown in the following.

[0129] Comparative Example 2

[0130] The comparative example provides a preparation method of a lithium titanium aluminum phosphate-carbon ionic electronic composite conductor, which is the same as that of Example 6 except that the lithium titanium aluminum phosphate precursor particles in step (1) are replaced by the solid electrolyte lithium titanium aluminum phosphate precursor obtained in Example 7 of CN118637585A.

[0131] Figure 11 and Figure 12 The SEM image and XRD pattern of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in the comparative example are shown in the following.

[0132] The lithium titanium aluminum phosphate-carbon ionic electronic composite conductor prepared in the above examples is subjected to SEM detection, and the particle size of the particles is tested by the SEM image.

[0133] The binding strength between the nano lithium titanium aluminum phosphate and the nano carbon in the nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor is evaluated: 10g of the lithium titanium aluminum phosphate-carbon ionic electronic composite conductor sample (the content of carbon in the composite conductor is denoted as a%) in Examples 1-10 and Comparative Examples 1-2 is respectively dispersed in 200g of ethanol by mechanical stirring for 0.5h, and after centrifugal separation, the upper liquid is dried and weighed. The ratio of the unbound nano carbon mass (y) separated from the nano lithium titanium aluminum phosphate-nano carbon ionic electronic composite conductor to the total sample mass is measured, and if y / total sample mass x 100% <0.01x a%, it indicates that the binding strength between the nano lithium titanium aluminum phosphate and the nano carbon is strong.

[0134] The test results of the above examples and comparative examples are shown in Table 1.

[0135] Table 1

[0136]

[0137] As can be seen from Table 1, the binding strength between the nano lithium aluminum titanium phosphate and the nano carbon in the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor in Examples 1-4 and Examples 7-8 is strong, and the binding strength between the nano lithium aluminum titanium phosphate and the nano carbon in the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor in Examples 5-6, Examples 9-10 and Comparative Examples 1-2 is weak.

[0138] Application Examples 2-3, Application Examples 5-10 and Application Comparative Examples 1-2

[0139] Application Examples 2-3, Application Examples 5-10 and Application Comparative Examples 1-2 provide an electrode material, which is the same as Application Example 1 except that the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor prepared by using Examples 2-3, 5-10 and Comparative Examples 1-2, respectively, is used, and details are not repeated here.

[0140] Application Example 4

[0141] The application example provides an electrode material, and a preparation method of the electrode material comprises: loading lithium cobaltate and the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor prepared by Example 4 into a special mixing tank of a high-speed mixer, wherein the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor accounts for 0.01wt% of the sum of the mass of the lithium cobaltate and the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor, and high-speed mixing is performed at a speed of 1500 rpm for 2 min to obtain a dry mixing material; and calcining the dry mixing material at 200°C for 4h to obtain lithium cobaltate coated with the nano lithium aluminum titanium phosphate-nano carbon ionic electronic composite conductor.

[0142] The discharge test: the coated positive electrode sample in Application Examples 1-10 and Application Comparative Examples 1-2, the conductive agent SuperP and the binder polyvinylidene fluoride (PVDF) are dispersed in NMP at a mass ratio of 95:3:2, mixed by a defoaming machine at a speed of 2000 rpm / min for 0.5h to obtain a uniformly mixed positive electrode slurry. The slurry is uniformly coated on the surface of an aluminum foil, and the coated electrode piece is placed in an oven and dried at 80°C for 3h, and then transferred to a vacuum drying oven and dried at 100°C for 12h to obtain a positive electrode piece. The positive electrode material piece is cut into a diameter of 14mm by a slicing machine, and the mass of the electrode piece is accurately weighed, with lithium metal as the negative electrode, PP separator, electrolyte 1M LiPF6 / DEC+EC+EMC, and the volume ratio of the solvents is 1:1:1, and CR2025 type button cells are assembled, wherein the assembly of the battery needs to be carried out in an argon glove box.

[0143] Cycling performance test: at room temperature 25℃, charge at 0.5C rate, then discharge at 1C rate, voltage range 2.7-4.5V, test discharge specific capacity, reciprocating cycle 100 times, test capacity retention rate after 100 cycles. Capacity retention rate = discharge specific capacity after 100 cycles / initial discharge specific capacity x 100%.

[0144] 4C rate discharge capacity ratio: the ratio of the capacity released by the battery at 4C rate to the capacity released by the battery at 0.1C rate in the activation stage.

[0145] The test results of the above application examples and application comparative examples are shown in Table 2.

[0146] Table 2

[0147]

[0148] From Table 2, the following points can be seen: the electrode materials provided by application examples 1-3 can improve the capacity retention rate of the batteries after the batteries are formed into button cells, and the initial discharge specific capacity is also considered; and the rate performance is excellent, and the 4C rate discharge capacity ratio is above 0.75.

[0149] In application comparative example 1 and application comparative example 2, the electrode materials formed into button cells not only have low initial discharge specific capacity, but also have significantly decreased cycling performance and rate performance compared with application example 1.

[0150] The above embodiments illustrate the detailed features of the present application, but the present application is not limited to the above detailed features, i.e. it does not mean that the present application must rely on the above detailed features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the technical features selected by the present application, addition of auxiliary technical features, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor, characterized in that, The nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor comprises nano-phosphor titanium aluminum lithium particles and nano-carbon material compounded with the nano-phosphor titanium aluminum lithium; the nano-phosphor titanium aluminum lithium comprises lithium, aluminum, titanium, oxygen and phosphorus; The compounding comprises close combination of the nano-phosphor titanium aluminum lithium and the nano-carbon material, and / or the nano-carbon material forms a coating layer on the surface of the nano-phosphor titanium aluminum lithium; The average primary particle size of the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor is 30-100 nm; The nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor has a dumbbell-shaped adhesion of nano-particles and a porous structure; the mass percentage of uncombined nano-carbon in the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor is 0.005-0.069%; The carbon content in the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor is 1%-15%.

2. The nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor according to claim 1, characterized in that, The molar ratio of lithium, aluminum, titanium and phosphorus in the nano-phosphor titanium aluminum lithium is (1+x):x:(2-x):3, wherein x is 0-0.5, but 0 is excluded; The nanoporous titanium aluminum lithium phosphate-nanocarbon ionic electronic composite conductor has a pore volume > 0.1 cm3 / g 3 / g; The average pore size of the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor is <10 nm; The specific surface area of the nano-titanium aluminum lithium phosphate-nano carbon ion electron composite conductor is 15-300 m 2 / g; The XRD spectrum of the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor has obvious diffraction peaks of LiTi2(PO4)3; The secondary particle size D50 of the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor is 1-30 μm.

3. A method of producing the nano-titanium aluminum lithium phosphate-nano-carbon ionic electronic composite conductor according to claim 1 or 2, characterized by, The preparation method comprises: (1) mixing lithium aluminum titanium phosphate precursor particles with a particle size of 5-30 nm and water, and dispersing to obtain a lithium aluminum titanium phosphate precursor aqueous slurry; wherein the lithium aluminum titanium phosphate precursor particles comprise lithium, aluminum, titanium, oxygen, hydrogen and phosphorus; (2) mixing a carbon source and the lithium aluminum titanium phosphate precursor aqueous slurry, and sequentially stirring, mixing, drying and calcining to obtain the nano-phosphor titanium aluminum lithium-nano-carbon ionic electronic composite conductor.

4. The production method according to claim 3, characterized by, In step (1), the peak intensity ratio of the first strong diffraction peak to the second strong diffraction peak in the XRD spectrum of the lithium aluminum titanium phosphate precursor particles is 0.5-2.0, and the half-height width of the first strong diffraction peak and the second strong diffraction peak ranges independently from 0.3 to 0.8°; wherein the peak position of the first strong diffraction peak is in the range of 26.5-27.5°, and the peak position of the second strong diffraction peak is in the range of 27.5-28.5°; The specific surface area of the lithium titanium aluminum phosphate precursor particles is 60-150 m 2 / g; The molar ratio of lithium, aluminum, titanium and phosphorus in the lithium aluminum titanium phosphate precursor particles is (1+x):x:(2-x):3, wherein x is 0-0.5, but 0 is excluded.

5. The production method according to claim 3 or 4, characterized by, The solid content of the lithium aluminum titanium phosphate precursor aqueous slurry in step (1) is 5-30 wt%; The dispersing comprises any one or a combination of at least two of sand mill dispersion, ball mill dispersion, high-speed shearing dispersion or defoaming machine stirring dispersion.

6. The production method according to claim 3 or 4, characterized by, In step (2), the carbon source comprises nano-carbon material and / or organic carbon source; The mass ratio of the lithium aluminum titanium phosphate precursor particles to carbon elements in the carbon source is 18.5:3-114.6:1; The calcination is performed in a protective atmosphere; The temperature of the calcination is 400-900°C; and the time of the calcination is 1-4h.

7. An electrode material, characterized by The electrode material comprises electrode powder and an electrode coating layer coated on the outside of the electrode powder; The material of the electrode coating layer comprises the nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor according to claim 1 or 2.

8. The electrode material of claim 7, wherein, The material of the electrode powder comprises any one or a combination of at least two of lithium cobalt oxide, spinel lithium manganate, spinel lithium nickel manganate, ternary material or lithium-rich manganese-based material; The average particle size of the electrode powder is greater than 2µm; The nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor accounts for 0.01-5wt% of the mass of the electrode material.

9. A method of producing the electrode material of claim 7 or 8, characterized in that, The method comprises mixing the electrode powder and the nano lithium aluminum titanium phosphate-nano carbon ion-electron composite conductor, and sequentially sintering and cooling to obtain the coated electrode material.

10. The method of claim 9, wherein, The temperature of the sintering is 200-600°C, and the time of the sintering is 1-4h; In the preparation process of the electrode material, the mixing step is performed in a high-speed mixer or a mechanical fusion machine.

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