CN114497548B - Nanoscale positive electrode material, preparation method and preparation device thereof and lithium ion battery - Google Patents

Nanoscale positive electrode material, preparation method and preparation device thereof and lithium ion battery Download PDF

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Publication number
CN114497548B
CN114497548B CN202210108299.7A CN202210108299A CN114497548B CN 114497548 B CN114497548 B CN 114497548B CN 202210108299 A CN202210108299 A CN 202210108299A CN 114497548 B CN114497548 B CN 114497548B
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depolymerization
collision
coating
nanoscale
cavity
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CN114497548A (en
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徐荣益
李亨利
孔令涌
李意能
刘其峰
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Foshan Dynanonic Technology Co ltd
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Foshan Dynanonic Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
    • H01M4/602—Polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy

Abstract

The invention provides a nanoscale anode material, a preparation method and a preparation device thereof and a lithium ion battery, wherein the preparation method comprises the following steps: the agglomerates of the positive electrode material are respectively ejected from opposite directions under high pressure for collision depolymerization, and then the depolymerized samples are obtained through particle size screening; and coating the depolymerized sample by an organic film to obtain the coated nanoscale anode material. The invention can depolymerize the agglomerated large particles into single small grains, and simultaneously coats an organic film on the outer surfaces of the small grains, so that the grains are dispersed, and the suspended state after depolymerization can be continuously screened and coated through the action of air flow, thereby improving the uniformity of the coating, and having great significance for improving the rate performance, low-temperature performance and high energy density brought by grading of the lithium battery.

Description

Nanoscale positive electrode material, preparation method and preparation device thereof and lithium ion battery
Technical Field
The invention relates to the technical field of preparation of lithium ion battery anode materials, in particular to a nanoscale anode material, a preparation method and a preparation device thereof and a lithium ion battery.
Background
The nano lithium iron phosphate crystal is synthesized by a hydrothermal method and a solvothermal method, so that the size and the morphology of crystal particles can be well controlled, but the method has the advantages of low yield, troublesome waste liquid treatment, potential safety hazard brought by a high-pressure environment and limitation of industrial application.
The solid phase synthesis method is a method commonly adopted in the current industrial production of lithium battery anode materials, is simple to operate and easy for large-scale production, but is easy to agglomerate into large particles among grains in the sintering process, so that nano-scale particles are difficult to obtain, and the charge and discharge performance is influenced. At present, the mode adopted in the industry is to crush agglomerated large particles through a material crusher, but the crushing precision is lower and is generally more than 0.1mm, the crushing is difficult to achieve the effect of depolymerizing into primary grains, and the multiplying power performance of the lithium battery is affected.
In addition, in the CVD coating process adopted by the carbon coating of some existing anode materials, the coating is carried out in a sagger or a tube furnace, and the uniformity of the coating in the upper, middle and lower materials is poor due to the accumulation of the materials, so that the charge-discharge performance and the stability performance of the lithium battery are affected.
Disclosure of Invention
In view of the problems in the prior art, the invention provides a nanoscale positive electrode material, a preparation method and a preparation device thereof, and a lithium ion battery, which can depolymerize phosphate positive electrode materials, solve the problem of reduced rate performance of the battery caused by agglomeration of active components in the preparation process of a solid-phase synthesis method, and have industrial application value.
To achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for preparing a depolymerized and enveloped integrated nanoscale cathode material, the method comprising:
the agglomerates of the positive electrode material are respectively ejected from opposite directions under high pressure for collision depolymerization, and then the depolymerized samples are obtained through particle size screening.
And coating the depolymerized sample by an organic film to obtain the coated nanoscale anode material.
In the preparation method provided by the invention, the agglomerated secondary particles (i.e. the agglomerates of the positive electrode material) are subjected to high-pressure spraying to collide, and the secondary particles are depolymerized into primary particles under the rigid collision of the solid particles; the depolymerized primary particles are coated by an organic film, so that a coated nano anode material can be obtained; compared with the traditional crushing method, the method provided by the invention can depolymerize the particles by adopting high-pressure injection, avoids the contact between the particles and the wall or crushing paddles by collision between the particles, almost has no carbonization and wall sticking of the particles, and the depolymerized particles are smaller, so that the method is applicable to the agglomeration of the anode material agglomerated into secondary particles, realizes the preparation of the nano anode material by a solid-phase synthesis method, and reduces the preparation cost of the nano anode material.
The average size of the nano-scale positive electrode material (final product) of the present invention is 100 to 800nm, and may be, for example, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 600nm, 700nm, 800nm, or the like.
Preferably, the nanoscale positive electrode material is a phosphate-based positive electrode active material. Further preferably, the nanoscale positive electrode material in the invention is a positive electrode material which is easy to form agglomerates when being roasted in a solid phase synthesis method, such as lithium iron phosphate, lithium manganese iron phosphate and the like, and is more suitable for the method of the invention.
Preferably, the preparation of the agglomerates comprises: and (3) roasting the precursor of the positive electrode material for one time to obtain an aggregate.
The preparation process of the positive electrode material precursor of the present invention is not particularly limited, and may be, for example, a liquid phase method or a commercially available conventional precursor, so long as the positive electrode material precursor is subsequently reacted by a solid phase synthesis method to obtain the positive electrode material.
Taking lithium iron phosphate as an example, the liquid phase method comprises: mixing a lithium source, an iron source and a phosphorus source, and reacting in a closed environment to obtain a positive electrode material precursor. The lithium source, the iron source and the phosphorus source are not particularly limited, and can be prepared into common materials for the skilled man in the art of preparing the anode material precursor, and can be adjusted conventionally according to actual conditions; wherein the lithium source may comprise, for example, at least one of lithium hydroxide, lithium oxide, lithium hydroxide monohydrate, lithium chloride, lithium nitrite, lithium nitrate, lithium oxalate, lithium carbonate, lithium acetate, lithium phosphate, lithium dihydrogen phosphate, or lithium dihydrogen phosphate; the iron source may include, for example, at least one of iron oxide, iron phosphate, iron chloride, iron sulfate heptahydrate, iron sulfate, iron hydroxide, iron nitrate, iron acetate, iron citrate, iron pyrophosphate, iron sulfate, iron phosphate, or iron oxalate; the phosphorus source may include, for example, at least one of phosphoric acid, diammonium phosphate, monoammonium phosphate, ammonium phosphate, iron phosphate, lithium phosphate, or lithium dihydrogen phosphate;
With lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X=0.01 to 0.8), the required raw materials further include a manganese source selected from at least one of manganese oxide, manganese acetate, manganese oxalate, manganese nitrate, manganese sulfate and manganese phosphate on the basis of the aforementioned lithium source, iron source and phosphorus source.
Preferably, a solvent is added to the liquid phase method, and the solvent contains an oxidizing substance, for example, the solvent may be an oxidizing solvent directly or a combination of a non-oxidizing solvent and an oxidizing agent, which is not particularly limited. Preferably, the solvent comprises an acidic solution, which may be, for example, hydrochloric acid, nitric acid, phosphoric acid, nitrous acid, sulfuric acid, acetic acid, hypochlorous acid, perchloric acid, or the like; when the acidic solution is a non-oxidizing solvent such as hydrochloric acid, phosphoric acid, acetic acid or hypochlorous acid, the oxidizing agent may be, for example, hydrogen peroxide and/or ozone water.
Preferably, the size of the agglomerates is not greater than 100 μm, and may be, for example, 800nm, 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 100 μm, or the like. It is further preferable to control the size of the agglomerate within the above range, which is more advantageous for collision and depolymerization.
Preferably, the primary calcination is performed in a protective atmosphere.
Preferably, the protective atmosphere comprises nitrogen.
The primary baking temperature is preferably 300 to 700 ℃, and may be, for example, 300 ℃, 400 ℃, 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 610 ℃, 630 ℃, 650 ℃, 670 ℃, 700 ℃, or the like, but is not limited to the values recited, and other values not recited in the range are equally applicable.
The time for the primary baking is preferably 8 to 30 hours, and may be, for example, 4 hours, 8 hours, 11 hours, 13 hours, 16 hours, 18 hours, 21 hours, 23 hours, 26 hours, 28 hours, or 30 hours, etc., but not limited to the recited values, and other values not recited in the range are equally applicable.
The pressure of the high-pressure injection is preferably in the range of 0.65 to 0.75MPa, and may be, for example, 0.65MPa, 0.67MPa, 0.68MPa, 0.69MPa, 0.7MPa, 0.71MPa, 0.72MPa, 0.73MPa, 0.74MPa, or 0.75MPa, etc., but is not limited to the values recited, and other values not recited in the range are equally applicable.
Preferably, the particle density of the agglomerates in the high-pressure jet air stream is 25 to 100g/m 3 For example, 25g/m 3 、30g/m 3 、40g/m 3 、50g/m 3 、60g/m 3 、70g/m 3 、80g/m 3 Or 100g/m 3 And the like, but are not limited to the recited values, and other non-recited values within this range are equally applicable.
The temperature of the agglomerate at the time of collision depolymerization is preferably 60 to 160 ℃, and may be 60 ℃, 70 ℃, 80 ℃, 100 ℃, 120 ℃, 150 ℃, 160 ℃ or the like, for example, but is not limited to the values recited, and other values not recited in the range are equally applicable.
In the present invention, the temperature of the agglomerate at the time of collision depolymerization is preferably controlled by the temperature of the first gas flow in the above range, and the depolymerization can be performed more favorably.
Preferably, the gas stream is preheated and then compressed to form a high pressure jet of gas.
The invention further preferably carries out preheating on the air flow, then compresses the air flow to form high-pressure jet air flow with temperature, and then carries out conveying and jetting of the agglomerates, thereby being more beneficial to ensuring that the temperature of the agglomerates is in the range of 60-160 ℃ during collision depolymerization.
The temperature of the high-pressure jet air flow is preferably 60 to 160 ℃, and may be 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 120 ℃, 140 ℃, 150 ℃, 160 ℃ or the like, for example, but is not limited to the values recited, and other values not recited in the range are equally applicable.
Preferably, the organic film coating method comprises a chemical vapor deposition method.
Preferably, the chemical vapor deposition method is a chemical vapor deposition method in a state of suspended particles. The invention further carries out chemical vapor deposition on the particles in a suspension state, which is more beneficial to improving the uniformity of the coating and further improving the multiplying power performance of the final battery.
Preferably, the organic film-coated organic material includes any one or a combination of at least two of paraffin, ethanol, polyethylene glycol, and polyvinylidene fluoride, wherein typical but non-limiting combinations are a combination of paraffin and ethanol, a combination of paraffin and polyvinylidene fluoride, a combination of polyvinylidene fluoride and ethanol, and a combination of ethanol and polyethylene glycol.
Preferably, the preparation method further comprises: and (3) carrying out secondary roasting on the coated nanoscale anode material to obtain a nanoscale anode material product.
Preferably, the secondary calcination is performed in a protective atmosphere.
Preferably, the protective atmosphere comprises nitrogen.
The temperature of the secondary baking is preferably 500 to 700 ℃, and may be 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 610 ℃, 630 ℃, 650 ℃, 670 ℃, 700 ℃, or the like, for example, but the secondary baking is not limited to the above-mentioned values, and other values not mentioned in the above range are equally applicable.
The secondary baking time is preferably 4 to 24 hours, and may be, for example, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours, etc., but is not limited to the recited values, and other values not recited in the range are equally applicable.
The present invention is not particularly limited, and any means and method known to those skilled in the art for roasting can be used, and may be adjusted according to the actual process, for example, constant temperature roasting, staged roasting or temperature programmed roasting, or the like, or may be a combination of different methods.
Preferably, the collision deagglomeration is performed in a collision deagglomeration chamber.
Preferably, the depolymerized sample enters the coating cavity after being subjected to particle size screening under the action of a first air flow introduced by a first air flow inlet, and is conveyed to a coating area of the coating cavity to be coated by an organic film under the action of a second air flow introduced by a second air flow inlet, so that the coated nanoscale anode material is obtained.
The invention preferably carries out depolymerization, screening and coating continuously through the airflow conveying and communicating collision depolymerization cavity and coating cavity, wherein the particle size of the primary particles after depolymerization is reduced, the primary particles can be upwards conveyed into the coating cavity under the action of the airflow introduced by the first airflow inlet, and can be continuously conveyed into a coating area (an area introduced with organic matters) for organic film coating under the action of the second airflow introduced by the second airflow inlet, so that the coated nano anode material can be obtained; the method integrates depolymerization, sorting and coating, avoids the problem of re-agglomeration in the process of re-stacking or conveying particles after conventional depolymerization, directly realizes CVD deposition in a suspension state, and further improves the uniformity of coating.
Preferably, the depolymerized sample passes through a particle size screening part and then is subjected to particle size screening, and enters a coating cavity to be coated with an organic film.
Preferably, the undeployed sample continues to undergo collisional depolymerization in the collisional depolymerization chamber under the influence of the first gas flow.
Preferably, the buoyancy generated by the first air flow at the depolymerization site of the collision depolymerization cavity corresponds to the gravity of the sample that is not depolymerized.
Preferably, the buoyancy generated by the first air flow at the upper part of the depolymerization part is smaller than the gravity of the sample which is not depolymerized and larger than the gravity of the sample after depolymerization.
Preferably, the buoyancy generated by the first gas flow at the lower part of the deagglomeration site is greater than the gravity of the sample that has not been deagglomerated.
In the present invention, it is preferable that the force generated by the first air flow at the depolymerization site (i.e., the high-pressure jet corresponding site) of the collision depolymerization cavity corresponds to the gravity of the undeployed sample, the undeployed sample is downward from the depolymerization site, the force generated by the air flow is greater than the gravity, and the undeployed sample is upward carried; the gravity is larger than the force generated by the airflow and falls downwards when the sample leaves the depolymerization part upwards, so that the sample which is not depolymerized is kept at the depolymerization part to continue collision depolymerization. The force generated by the first air flow when the sample is at the depolymerization position after depolymerization is greater than the gravity of the sample after depolymerization, and the sample is carried upwards to realize separation from the sample which is not depolymerized.
Preferably, the first gas flow flows from bottom to top.
The temperature of the first air flow is preferably 90 to 190 ℃, and may be, for example, 90 ℃, 100 ℃, 120 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, or the like, but is not limited to the values recited, and other values not recited in the range are equally applicable.
The invention preferably heats the first airflow and then introduces the heated airflow into the collision depolymerization cavity, thereby providing proper temperature for depolymerization, being more beneficial to the collision depolymerization and improving the depolymerization effect.
The invention preferably controls the temperature of the agglomerate during collision depolymerization at 60-160 ℃ by adjusting the temperature of the first air flow and/or the high-pressure jet air flow, and the collision depolymerization effect is better.
Preferably, the first gas stream comprises a nitrogen gas stream.
The preparation method of the depolymerization and coating integrated nanoscale anode material has no special requirements on the adopted device, but is preferably carried out by adopting the preparation device in the second aspect, so that depolymerization, screening and coating can be integrated, re-stacking agglomeration is avoided, coating uniformity is improved in a suspension state, integrated continuous operation is realized, and industrial production is facilitated.
In a second aspect, the invention provides a preparation device for a depolymerization and coating integrated nanoscale cathode material, wherein the preparation device comprises a coating cavity and a collision depolymerization cavity which are communicated from top to bottom; the collision depolymerization cavity is arranged at the lower part of one side of the cladding cavity;
the bottom of the collision depolymerization cavity is provided with a first gas inflow port; at least one group of opposite material inlets are arranged at the opposite positions of the side wall of the collision depolymerization cavity; the material inlet is connected with a material conveying device which is a high-pressure pneumatic conveying device;
And one end of the cladding cavity, which is close to the collision depolymerization cavity, is provided with a second air flow inlet which is horizontally introduced.
According to the preparation device for the depolymerization and coating integrated nanoscale anode material, provided by the first aspect of the invention, depolymerization and coating can be realized in the same device, and due to the effect of air flow introduced into the first air flow inlet, the distinction between a depolymerized sample and a sample which is not depolymerized can be realized, the depolymerized sample is coated, and the sample which is not depolymerized can be continuously depolymerized, so that the preparation device is beneficial to industrial production.
According to the invention, at least one group of opposite material inlets are arranged at opposite positions of the side wall of the collision depolymerization cavity, and depolymerization among agglomerated particles is realized through rigid collision among moving solid particles and solid particles; the particles after depolymerization of the third invention are smaller than the particles obtained by the crusher, so that the preparation of the nano-scale anode material can be realized.
Preferably, the second air flow inlet is directly connected with the cladding cavity.
The invention is not limited in particular to the structural design of the material inlet nozzle and the like, and the material inlet nozzle can be properly adjusted according to actual conditions by adopting a structure well known to a person skilled in the art.
Preferably, the high-pressure pneumatic conveying device comprises a material transfer box and an air compressor.
Preferably, the high-pressure air conveying device further comprises an air preheating device connected with the air compressor.
The invention further preferably preheats the air and then compresses the air to form high-pressure airflow with temperature, which is beneficial to guaranteeing the temperature of the agglomerate during collision depolymerization and improving the effect of collision depolymerization.
Preferably, the first gas flow inlet and the second gas flow inlet are connected to a gas supply device separately or together.
In the present invention, it is further preferable that a flow rate control means is provided between the gas supply device and the first gas flow inlet and the second gas flow inlet, and the flow rate control means is not particularly limited, and a means capable of controlling the flow rate of the gas, which is well known to those skilled in the art, may be employed, for example, a mass flow rate controller or the like, and the accuracy thereof may be adjusted and selected according to actual needs, and the flow rate control means is not limited.
Preferably, an organic carbon source inlet is arranged at one side of the upper part of the coating cavity, and the organic carbon source inlet is arranged at one side far away from the collision depolymerization cavity.
Preferably, an exhaust pipe is arranged in the cladding cavity.
Preferably, the exhaust pipe extends into the lower portion of the cladding cavity. So that the organic gas source and nitrogen are preferably vented.
Preferably, the organic carbon source inlet is connected with an organic carbon source gasification device and/or an organic carbon source atomization device.
Preferably, a flow control valve is provided at the organic carbon source inlet.
Preferably, a particle size screening member is provided between the coating chamber and the collision deagglomeration chamber.
Preferably, the particle size screening means comprises a screen.
The size of the screen is not particularly limited in the present invention, and may be designed and adjusted according to the size of the primary particles before the initial agglomeration.
Preferably, a gas injection port is provided above the particle size screening member, and the gas injection port is connected to a gas conveying device. In the present invention, it is further preferable that the gas injection port is provided at the top of the coating chamber and located directly above the particle diameter screening member.
Preferably, the gas conveying device can jet high-pressure nitrogen so as to blow out the blocked particles, and the regular cleaning of the particle size screening component is realized.
Preferably, a first connection is provided on the wall between the cladding cavity and the collision deagglomeration cavity.
Preferably, the particle size screening member is detachably connected to the first connecting portion through the second connecting portion.
The present invention is not particularly limited to the first connecting portion and the second connecting portion, and any means or device for detachable connection known to those skilled in the art may be used, for example, the first connecting portion may be a protrusion, and the second connecting portion may be a groove provided on the circumference of the particle size screening means in matching with the protrusion of the snap ring; the shape of the protrusion and the groove can realize fixed connection and disassembly; or for example, the first connecting portion is a first thread, the second connecting portion is a second thread which is matched with the first thread and is arranged on the periphery side of the particle size screening component, and the first thread and the second thread can be detachably connected through a screw.
Preferably, the preparation device further comprises a collecting component communicated with one side of the lower part of the coating cavity.
The invention is further provided with a collecting component, so that the collection of the coated nanoscale anode material can be effectively realized.
Preferably, the collection means comprises a collection bin.
Preferably, the collecting box is provided with an exhaust port. It is preferable to be able to discharge the excess gas.
Preferably, the collecting member is detachably connected to the lower portion of the covering chamber. The detachable connection mode is not particularly limited, and can be connected by a flange and other parts commonly used by those skilled in the art.
Preferably, the collecting member is disposed in communication with a lower side of the organic carbon source inlet.
Preferably, a gas phase outlet is provided at one side of the upper portion of the collecting member for the discharge of the gas stream and the organic gas.
In a third aspect, the invention provides a nanoscale positive electrode material, which is prepared by the preparation method of the depolymerization and coating integrated nanoscale positive electrode material in the first aspect.
The nanoscale positive electrode material provided by the third aspect of the invention has small particle size, uniform coating, capability of industrial production and wide application prospect.
In a fourth aspect, the present invention provides a lithium ion battery comprising the nanoscale cathode material according to the third aspect.
The lithium ion battery provided by the invention has higher multiplying power performance and stability performance because the lithium ion battery contains the nanoscale anode material.
The negative electrode material, the electrolyte, the current collector and the like in the lithium ion battery are not particularly limited, and any negative electrode material, electrolyte and current collector which are well known to those skilled in the art and can be used for the lithium ion battery can be adopted, and the invention can also be adjusted according to actual technology.
Compared with the prior art, the invention has at least the following beneficial effects:
(1) The preparation device of the depolymerization and coating integrated nanoscale anode material provided by the invention has a simple structure, can integrate depolymerization, separation and coating, and is beneficial to the industrial production of the nanoscale anode material;
(2) According to the preparation method of the depolymerization and coating integrated nanoscale anode material, rigid collision among solid particles in motion is realized by utilizing a high-pressure injection mode, so that the effect of converting secondary particles into primary particles is achieved, the particle size is small, and the average particle size is within 400 nm;
(3) According to the preparation method of the depolymerization and coating integrated nanoscale anode material, chemical vapor deposition coating is realized after depolymerization, and coating is carried out in a suspension state, so that the uniformity of the coating is improved, and the electrical property of the anode material is further improved; the difference of the average film thickness of the upper, middle and lower parts of the quartz boat/collecting box is preferably within 0.07nm, the preferred difference of the 0.1C discharge capacity of the upper, middle and lower parts of the quartz boat/collecting box is preferably within 0.9mAh/g, and the depolymerization, the separation and the coating are continuously carried out, so that the depolymerized positive electrode materials can be effectively prevented from being agglomerated again;
(4) The positive electrode material prepared by the preparation method of the depolymerization and coating integrated nanoscale positive electrode material provided by the invention has high rate performance, wherein 10C discharge capacity is more than 130.1mAh/g, 3C discharge capacity is more than 142.5mAh/g, 1C discharge capacity is more than 151.6mAh/g, 0.1C discharge capacity is more than 155.9mAh/g, 10C discharge capacity is preferably more than 135.2mAh/g, 3C discharge capacity is preferably more than 149.5mAh/g, 1C discharge capacity is more than 154.1mAh/g, and 0.1C discharge capacity is more than 158.4 mAh/g.
Drawings
Fig. 1 is a diagram of an apparatus for preparing a depolymerized and enveloped integrated nanoscale cathode material according to example 1 of the present invention.
Fig. 2 is a diagram of a device for preparing a depolymerized and enveloped integrated nanoscale cathode material according to example 2 of the present invention.
FIG. 3 shows LiMn in application example 1 of the present invention 0.03 Fe 0.97 PO 4 XRD patterns of the products.
FIG. 4 shows LiMn in application example 1 of the present invention 0.03 Fe 0.97 PO 4 SEM image of the product.
FIG. 5 shows LiMn in application example 2 of the present invention 0.3 Fe 0.7 PO 4 XRD patterns of the products.
FIG. 6 shows LiMn in application example 2 of the present invention 0.3 Fe 0.7 PO 4 SEM image of the product.
In the figure: 1-cladding the cavity; 2-collision deagglomeration chamber; 3-a collection member; 4-a particle size screening means; 5-a first gas flow inlet; 6-a second gas flow inlet; 7-an organic carbon source inlet; 8-material inlet; 9-gas injection port; 10-exhaust pipe.
Detailed Description
The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.
The present invention will be described in further detail below. The following examples are merely illustrative of the present invention and are not intended to represent or limit the scope of the invention as defined in the claims.
It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature.
It should be noted that, in the description of the present invention, unless explicitly specified and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
It will be appreciated by those skilled in the art that the present invention necessarily includes the necessary piping, conventional valves and general pumping equipment for achieving the process integrity, but the foregoing is not a major inventive aspect of the present invention, and that the present invention is not particularly limited thereto as the layout may be added by themselves based on the process flow and the equipment configuration options.
Example 1
The embodiment provides a preparation device of a depolymerization and coating integrated nanoscale anode material, which comprises a coating cavity 1 and a collision depolymerization cavity 2 which are communicated from top to bottom as shown in fig. 1; the collision depolymerization cavity 2 is arranged at the lower left side of the cladding cavity 1;
The bottom of the collision depolymerization cavity 2 is provided with a first gas inflow port 5; the side wall of the collision deagglomeration chamber 2 is provided with a set of opposed material inlets 8 (i.e. two material inlets) in opposite positions. The material inlet 8 is connected with a material conveying device, and the material conveying device is a high-pressure pneumatic conveying device which is used for providing and controlling conveying pressure. Preferably, the high-pressure conveying device comprises a material transfer box and an air compressor, the air compressor is connected with an air preheating device, the material to be coated is conveyed into the material transfer box in batches, and the air preheated by the air preheating device provides high-pressure gas with temperature from the air compressor into the material transfer box, so that agglomerates of the positive electrode material enter the collision depolymerization cavity 2 from the material inlet 8 in a high-speed injection mode.
The left end of the cladding cavity 1, which is close to the collision depolymerization cavity 2, is provided with a second air flow inlet 6 which is horizontally introduced. The second air inlet 6 is directly connected with the cladding cavity 1. The first gas flow inlet 5 and the second gas flow inlet 6 are connected with the same gas supply device together; a flow rate control means is provided between the gas supply means and the first and second gas flow inlets 5 and 6 to control the flow rates of the two gas flow inlets, respectively. An exhaust pipe 10 is arranged in the cladding cavity 1. The exhaust pipe 10 extends into the lower part of the cladding cavity 1, and the exhaust pipe 10 is used for exhausting gas.
An organic carbon source inlet 7 is arranged on the right side of the upper part of the coating cavity 1, and the organic carbon source inlet 7 is arranged on one side far away from the collision depolymerization cavity 2; the organic carbon source inlet 7 is connected with an organic carbon source gasification device. And a flow control valve is arranged at the organic carbon source inlet 7 and used for controlling the conveying flow rate of the gasified organic carbon source.
A particle size screening component 4 is arranged between the coating cavity 1 and the collision depolymerization cavity 2; the particle size screening means 4 comprises a screen; a gas injection port 9 is provided above the particle size screening member 4, and a gas delivery device (not shown) is connected to the gas injection port 9. The gas conveying device can spray high-pressure nitrogen, so that blocked particles can be blown out, and the particle size screening component can be cleaned at regular time. A first connecting part is arranged on the wall between the cladding cavity 1 and the collision depolymerization cavity 2; the particle size screening component 4 is detachably connected with the first connecting part through the second connecting part; the first connecting portion is protruding, the second connecting portion for with protruding assorted recess of snap ring setting in particle diameter screening part 4 week side, dismantle and wash particle diameter screening part 4 after long-time operation through detachable part.
The preparation device also comprises a detachable collecting component 3 (which is detachably connected through a flange and is convenient for maintenance and cleaning after long-time operation) which is communicated with the right side of the lower part of the cladding cavity 1; the collecting member 3 is disposed at a lower side corresponding to the organic carbon source inlet 7. A gas phase outlet (not shown) is provided at one side of the upper portion of the collecting member 3 for discharging the gas stream and the organic gas; the collecting member 3 is a collecting tank.
Example 2
The embodiment provides a preparation device of a depolymerization and coating integrated nanoscale anode material, which comprises a coating cavity 1 and a collision depolymerization cavity 2 which are communicated from top to bottom as shown in fig. 2; the collision depolymerization cavity 2 is arranged at the lower right side of the cladding cavity 1;
the bottom of the collision depolymerization cavity 2 is provided with a first gas inflow port 5; two groups of opposite material inlets 8 (namely 4 material inlets) are arranged at the opposite positions of the side wall of the collision depolymerization cavity 2; the material inlet 8 is connected with a material conveying device, the material conveying device is a high-pressure pneumatic conveying device, and the high-pressure pneumatic conveying device can be used for controlling conveying pressure. The high-pressure pneumatic conveying device is used for providing and controlling conveying pressure. Preferably, the high-pressure conveying device comprises a material transfer box and an air compressor, the air compressor is connected with an air preheating device, aggregates of the positive electrode material are conveyed into the material transfer box in batches, and air preheated by the air preheating device provides high-pressure gas with temperature from the air compressor into the material transfer box, so that the material to be coated enters the collision depolymerization cavity 2 from the material inlet 8 in a high-speed injection mode.
The right end of the cladding cavity 1, which is close to the collision depolymerization cavity 2, is provided with a second air flow inlet 6 which is horizontally introduced. The second air inlet 6 is directly connected with the cladding cavity 1. The first gas flow inlet 5 and the second gas flow inlet 6 are respectively connected with two gas supply devices; flow rate control means are provided between the gas supply means and the first and second gas flow inlets 5, 6, respectively, for controlling the flow rates of the two gas flow inlets, respectively. An exhaust pipe 10 is arranged in the cladding cavity 1. The exhaust pipe 10 extends into the lower part of the cladding cavity 1, and the exhaust pipe 10 is used for exhausting gas.
An organic carbon source inlet 7 is arranged at the left side of the upper part of the coating cavity 1, and the organic carbon source inlet 7 is arranged at one side far away from the collision depolymerization cavity 2; the organic carbon source inlet 7 is connected with an organic carbon source atomizing device. And a flow control valve is arranged at the organic carbon source inlet 7 and used for controlling the conveying flow rate of the gasified organic carbon source.
A particle size screening component 4 is arranged between the coating cavity 1 and the collision depolymerization cavity 2; the particle size screening means 4 comprises a screen; a gas injection port 9 is provided above the particle size screening member 4, and a gas delivery device (not shown) is connected to the gas injection port 9. The gas conveying device can spray high-pressure nitrogen, so that blocked particles can be blown out, and the particle size screening component can be cleaned at regular time. A first connecting part is arranged on the wall between the cladding cavity 1 and the collision depolymerization cavity 2; the particle size screening component 4 is detachably connected with the first connecting part through the second connecting part; the first connecting part is a first thread, the second connecting part is a second thread which is matched with the first thread and is arranged on the periphery side of the particle size screening part 4, and the first thread and the second thread can be detachably connected through screws
The preparation device also comprises a detachable collecting part 3 (which is detachably connected through a clamping ring and is convenient for maintenance and cleaning after long-time operation) which is communicated with the left side of the lower part of the cladding cavity 1; the collecting member 3 is disposed at a lower side corresponding to the organic carbon source inlet 7. A gas phase outlet (not shown) is provided at one side of the upper portion of the collecting member 3 for discharging the gas stream and the organic gas; the collecting member 3 is a collecting tank.
Application example 1
The application example provides a preparation method of a depolymerization and coating integrated nanoscale anode material, which comprises the following steps:
(1) 74.34g Li 2 CO 3 、155.84g Fe 2 O 3 、300g(NH 4 ) 3 PO 4 、5.25g MnO 2 And 130g of 48% (weight percentage) nitric acid and 300g of water are uniformly mixed, the air pressure and the reaction temperature are monitored under a high-pressure closed environment, the pressure is relieved when the air pressure is increased to 0.3MPa, the liquid phase reaction is completed, and the raw material solid mixture LiMn is prepared 0.03 Fe 0.97 PO 4 A precursor;
(2) The LiMn 0.03 Fe 0.97 PO 4 Roasting the precursor for 12 hours at 500 ℃ in a nitrogen atmosphere to obtain an aggregate with the maximum secondary particle size of 100 mu m;
(3) The preparation apparatus of example 1 was used, the agglomerates being transported by means of a high-pressure pneumatic conveyor with a particle density of 50g/m of agglomerates in the gas stream 3 Respectively jetting the materials from opposite directions into a collision depolymerization cavity under high pressure to carry out collision depolymerization, and controlling the temperature of the aggregates during the collision depolymerization to be 100 ℃ through the temperature of a first airflow (the temperature is 120 ℃) and a high-pressure airflow (the temperature is 100 ℃) to obtain a depolymerized sample; the pressure of the high-pressure injection was 0.75MPa.
The depolymerized sample is carried out of a 50000-mesh screen from bottom to top under the action of a first air flow (nitrogen) introduced by a first air flow inlet and enters a coating cavity, and is conveyed to a coating area filled with paraffin steam under the action of a second air flow (nitrogen) introduced by a second air flow inlet to be coated by paraffin films, the residence time is 3-5 s, and a coated nanoscale anode material coated with a 5nm thick paraffin layer is collected from a collecting box;
the undeployed sample can not pass through a 50000 mesh screen, and is driven by a first airflow to continue collision depolymerization in a collision depolymerization cavity to form single grains;
(4) Directly placing a collecting box for collecting the coated nanoscale anode material in a nitrogen atmosphere, and carrying out secondary roasting at 600 ℃ for 4 hours (the distribution of the nanoscale anode material in the collecting box is not disturbed, so that the coating condition of the nanoscale anode material at the upper, middle and lower layers of the collecting box is conveniently analyzed) to obtain the nanoscale LiMn 0.03 Fe 0.97 PO 4 And (5) a product.
Nanoscale LiMn prepared in this example 0.03 Fe 0.97 PO 4 The XRD characterization pattern of the product is shown in FIG. 3, and it can be seen from FIG. 3 that LiMn of the present example 0.03 Fe 0.97 PO 4 The product is basically matched with a standard card, and a hetero-phase peak is not introduced; the SEM characterization results are shown in FIG. 4, and it can be seen from FIG. 4 that the primary particle size distribution is relatively uniform, with an average of 300nm.
Application example 2
The application example provides a preparation method of a depolymerization and coating integrated nanoscale anode material, which comprises the following steps:
(1) 99.12g Li 2 CO 3 、149.95g Fe 2 O 3 、400g(NH 4 ) 3 PO 4 、69.97g MnO 2 And 90g of 40% (weight percentage) hydrochloric acid are uniformly mixed, the air pressure and the reaction temperature are monitored under a high-pressure closed environment, the pressure is relieved when the air pressure is increased to 0.2MPa, the liquid phase reaction is completed, and the raw material solid mixture LiMn is prepared 0.3 Fe 0.7 PO 4 A precursor;
(2) The LiMn 0.3 Fe 0.7 PO 4 Roasting the precursor for 24 hours at 300 ℃ in a nitrogen atmosphere to obtain an aggregate with the maximum secondary particle size of 100 mu m;
(3) The preparation apparatus of example 2 was used, the agglomerates being transported by means of a high-pressure pneumatic conveyor with a particle density of 100g/m of agglomerates in the gas stream 3 Respectively jetting the materials from opposite directions into a collision depolymerization cavity under high pressure to carry out collision depolymerization, and controlling the temperature of the aggregates to 160 ℃ during the collision depolymerization through the temperature of a first air flow (temperature 190 ℃) and a high-pressure air flow (temperature 160 ℃) to obtain a depolymerized sample; the pressure of the high-pressure injection was 0.70MPa.
The depolymerized sample is carried out of a 100000-mesh screen from bottom to top under the action of a first air flow (nitrogen) introduced by a first air flow inlet and enters a coating cavity, and is conveyed to a coating area filled with polyethylene glycol steam under the action of a second air flow (nitrogen) introduced by a second air flow inlet to be coated by a polyethylene glycol film, the residence time is 6-9 s, and the coated nanoscale anode material coated with an 8nm thick polyethylene glycol layer is collected from a collecting box;
The undeployed sample cannot pass through a 100000-mesh screen, and is driven by a first airflow to continue collision depolymerization in a collision depolymerization cavity to form single grains;
(4) Directly placing a collecting box for collecting the coated nanoscale anode material in a nitrogen atmosphere, and carrying out secondary roasting at 500 ℃ for 6 hours (the distribution of the nanoscale anode material in the collecting box is not disturbed, so that the coating condition of the nanoscale anode material at the upper, middle and lower layers of the collecting box is conveniently analyzed) to obtain the nanoscale LiMn 0.3 Fe 0.7 PO 4 And (5) a product.
Nanoscale LiMn prepared in this example 0.3 Fe 0.7 PO 4 The XRD characterization of the product is shown in FIG. 5, and it can be seen from FIG. 5 that LiMn of the present example 0.3 Fe 0.7 PO 4 The product is basically matched with a standard card, and a hetero-phase peak is not introduced; the SEM characterization results are shown in FIG. 6, and it can be seen from FIG. 6 that the particle size distribution is relatively uniform, with an average of 150nm.
Application example 3
(1) 138.74g LiNO is taken 3 、195.83g FeCl 3 、300g(NH 4 ) 2 HPO 4 、345.55g Zr(NO 3 ) 2 60g of 60% (weight percentage) nitric acid and 250g of water are uniformly mixed, the air pressure and the reaction temperature are monitored under a high-pressure closed environment, the pressure is relieved when the air pressure is increased to 0.3MPa, the liquid phase reaction is completed, and the raw material solid mixture LiZr is prepared 0.4 Fe 0.6 PO 4 A precursor;
(2) The LiZr 0.4 Fe 0.6 PO 4 Roasting the precursor for 30 hours at 200 ℃ in a nitrogen atmosphere to obtain an aggregate with the average secondary particle diameter of 100 mu m at maximum;
(3) The preparation apparatus of example 2 was used, the agglomerates being transported by means of a high-pressure pneumatic conveyor with a particle density of 25g/m of agglomerates in the gas stream 3 Respectively injecting the materials from opposite directions into a collision depolymerization cavity for collision depolymerization, and controlling the temperature of the agglomerates at 60 ℃ during collision depolymerization by the temperature of a first air flow (temperature 90 ℃) and a high-pressure air flow (temperature 60 ℃) to obtainTo depolymerized samples; the pressure of the high-pressure injection was 0.68MPa.
The depolymerized sample is carried out of a 160000 mesh screen from bottom to top under the action of a first air flow (nitrogen) introduced by a first air flow inlet and enters a coating cavity, and is conveyed to a coating area filled with polyvinylidene fluoride steam under the action of a second air flow (nitrogen) introduced by a second air flow inlet to be coated by a polyvinylidene fluoride film, the residence time is 2-5 s, and the nano-scale anode material coated with a 4nm thick polyvinylidene fluoride layer is collected from a collecting box;
the undeployed sample cannot pass through a 160000 mesh screen, and is driven by a first airflow to continue collision depolymerization into single grains in a collision depolymerization cavity;
(4) Directly placing a collecting box for collecting the coated nanoscale anode material in a nitrogen atmosphere, and carrying out secondary roasting at 700 ℃ for 15 hours (the distribution of the nanoscale anode material in the collecting box is not disturbed, so that the coating condition of the nanoscale anode material at the upper, middle and lower layers of the collecting box is conveniently analyzed), thereby obtaining the nanoscale LiZr 0.4 Fe 0.6 PO 4 The product has uniform particle size distribution and average particle size of 90nm.
Application example 4
The application example provides a preparation method of a depolymerization and coating integrated nanoscale anode material, which comprises the following steps:
(1) 73.32g LiOH and 612.12g Fe are taken 2 (SO 4 ) 3 、300g H 3 PO 4 50g of 20% (weight percentage) nitrous acid and 150g of water are uniformly mixed, the air pressure and the reaction temperature are monitored under a high-pressure closed environment, the pressure is relieved when the air pressure is increased to 0.6MPa, the liquid phase reaction is completed, and the raw material solid mixture LiFePO is prepared 4 A precursor;
(2) The LiFePO 4 Roasting the precursor for 8 hours at 500 ℃ in a nitrogen atmosphere to obtain an aggregate with the maximum secondary particle size of 100 mu m;
(3) The preparation apparatus of example 2 was used, the agglomerates being transported by means of a high-pressure pneumatic conveyor with a particle density of 55g/m of agglomerates in the gas stream 3 Respectively from opposite direction high pressure jet into collision depolymerization cavity to make collision depolymerization, pass throughControlling the temperature of the agglomerate to 120 ℃ during collision depolymerization by the temperature of a gas flow (temperature 140 ℃) and a high-pressure gas flow (temperature 120 ℃) to obtain a depolymerized sample; the pressure of the high-pressure injection was 0.73MPa.
The depolymerized sample is carried out of a 60000 mesh screen from bottom to top under the action of a first air flow (nitrogen) introduced by a first air flow inlet and enters a coating cavity, and is conveyed to a coating area filled with paraffin steam under the action of a second air flow (nitrogen) introduced by a second air flow inlet to be coated by paraffin film, the residence time is 4-6 s, and the coated nanoscale anode material coated with a 6nm thick paraffin layer is collected from a collecting box;
The undeployed sample cannot pass through a 60000 mesh screen, and is driven by a first airflow to continue collision depolymerization in a collision depolymerization cavity to form single grains;
(4) Directly placing a collecting box for collecting the coated nanoscale anode material in a nitrogen atmosphere, and performing secondary roasting at 500 ℃ for 18 hours (the distribution of the nanoscale anode material in the collecting box is not disturbed, so that the coating condition of the nanoscale anode material at the upper, middle and lower layers of the collecting box is conveniently analyzed) to obtain nanoscale LiFePO 4 The product has uniform particle size distribution and average particle size of 250nm.
Application example 5
The application example provides a preparation method of a depolymerized and coated nanoscale cathode material, which is different from application example 1 only in that: the device provided in example 1 is not adopted, the agglomerate obtained by the primary sintering of the precursor is subjected to high-pressure injection depolymerization, the mixture obtained after depolymerization is taken out to be screened independently, and then the coating and secondary sintering are carried out independently.
The specific step (3) is as follows: the agglomerates are respectively ejected into a collision depolymerization cavity from opposite directions under high pressure to carry out collision depolymerization, so that a depolymerized mixed sample is obtained; the pressure of the high-pressure injection was 0.75MPa.
The mixed sample is sieved by a 50000-mesh screen to obtain depolymerized particles with smaller particle size, and the depolymerized particles are placed in a quartz boat; the particles with larger particle diameters after sieving are continuously sprayed into a collision depolymerization cavity from opposite directions under high pressure to carry out collision depolymerization;
And (3) placing the quartz boat containing the depolymerized particles with smaller particle size into a coating device, and coating the quartz boat with paraffin film in the coating device filled with paraffin vapor for 3-5 s to obtain the coated nanoscale anode material coated with the paraffin film with the thickness of 5 nm. And directly performing secondary sintering on the materials in the quartz boat after the film coating is finished.
The application example realizes depolymerization and coating, but compared with application example 1, the process is divided into three sections, the operation is complex, and the high-pressure injection depolymerization is required to be repeatedly carried out on the large particles after screening, so that the energy consumption is large, the partial agglomeration condition exists when the depolymerized particles with smaller particle size are transferred into a coating device, and the average particle size obtained finally is larger than that of application example 1, and the average particle size is 400nm; the disaggregated particles were stacked in a coating apparatus to be coated, and the uniformity of the coated film was lower than that in the suspension state of application example 1.
Application example 6
The application example provides a preparation method of a depolymerized and coated nanoscale cathode material, which is different from application example 1 only in that: the temperature of the agglomerate during collision depolymerization is 30 ℃, and the average particle size of the obtained product is 330nm.
Application example 7
The application example provides a preparation method of a depolymerized and coated nanoscale cathode material, which is different from application example 1 only in that: the temperature of the agglomerate during collision depolymerization is 180 ℃, and the average grain diameter of the obtained product is 260nm.
Comparative example 1
This comparative example provides a method for preparing a depolymerized and coated nanoscale cathode material, which differs from application example 1 only in that: the high pressure jet is replaced by a stirring crusher for crushing.
Compared with the application example 1, the process is still three sections, the process is complex, the materials are smashed by collision of the stirring component and the materials in the smashing process of the stirring crusher, for solid materials, the stirring component continuously impacts the materials to generate a large amount of heat so that the materials are carbonized and are not easy to fall off due to wall sticking, and finally, hard blocks are formed on the stirring component, so that the finally obtained nano-scale anode material is doped with impurities and the yield is reduced; in addition, the depolymerization is more thorough in application example 1, so that the material is in a suspension state, secondary agglomeration is avoided, and the nano-scale anode material can be obtained.
Comparative example 2
This comparative example provides a method of preparing a nanoscale positive electrode material using a hydrothermal preparation method, specifically example 1 of CN 104600294B.
Comparative example 3
This comparative example provides a method for preparing a micro-nano structured lithium iron manganese phosphate positive electrode material, specifically, example 1 of CN 104167549B.
Comparative example 4
This comparative example provides a method of preparing a nanoscale positive electrode material, specifically example 1 of CN 103762362B.
The comparative examples 2 to 4 were each carried out by a hydrothermal method or a solvothermal method, and although nano-sized particles could be produced, the productivity was low, the waste liquid treatment was difficult, and the potential safety hazard was brought about in a high-pressure environment, and the industrial application was difficult.
The invention takes application example 1 as an example to prepare a lithium battery and test the multiplying power performance. The present invention is not particularly limited to the practical application of the positive electrode material, and only the preparation and test process of the detailed button cell is given for the performance test. The method comprises the following steps:
and (3) manufacturing a button cell: 800g of nano-scale LiMn 0.3 Fe 0.7 PO 4 Active components (nano LiMn on the upper, middle and lower parts of quartz boat/collection box) 0.3 Fe 0.7 PO 4 Collecting and uniformly mixing all active components, taking 800 g), 100g of conductive agent acetylene black and 100g of binder polyvinylidene fluoride (PVDF), adding into 800g of N-methylpyrrolidone solution (NMP solution), and stirring in a vacuum stirrer for 2 hours to prepare anode slurry; the slurry is uniformly coated on an aluminum foil, and then the aluminum foil is placed in a vacuum drying oven for drying at 120 ℃ for 12 hours, and a wafer with the diameter of 14mm is punched after rolling to be used as a positive plate. The positive electrode sheet, the negative electrode sheet (metal lithium sheet with the diameter of 14.5 mm) and the diaphragm (Celgard 2400 micropore) The polypropylene film) and the electrolyte (1 mo1/LLiPF6/EC+DMC (volume ratio 1:1) were assembled into a CR2025 button lithium ion battery in a glove box filled with hydrogen.
And (3) charge and discharge testing: and (3) carrying out charge and discharge test on the manufactured test battery by using a lithium ion battery charge and discharge test system under the conditions of 25+/-0.5 ℃ and the charge and discharge conditions: a charge termination voltage of 3.75V; a discharge termination voltage of 2.00V; charge-discharge current density: 0.1C, 1C, 3C and 10C. Film coating uniformity test: the thickness and uniformity of the film of the coated nanoscale positive electrode material were examined by sample TEM.
Application examples 2 to 7 and comparative example 1 were carried out by referring to the test method of application example 1, and the test results are shown in tables 1 and 2.
TABLE 1
TABLE 2
From table 1, the following points can be seen:
(1) The comprehensive application examples 1-4 show that the preparation method of the depolymerization and coating integrated nanoscale positive electrode material can prepare the nanoscale positive electrode material, wherein the average particle size of the prepared nanoscale positive electrode material is within 300 nm; the coating of the nano-scale anode material is uniform, and the difference of the average film thickness of the quartz boat/collecting box is within 0.07 nm; the rate performance is high, the 10C discharge capacity is more than 133.2mAh/g, and the 3C discharge capacity is more than 147.8 mAh/g;
(2) As can be seen from the comprehensive application examples 1 and 5, application example 1 is performed by using the device provided in example 1, and coating is performed in a suspension state, compared with application example 5 in which the coating is performed in a depolymerization state and then in a separate stacking state, the average particle size of the product in application example 1 is 300nm, the discharge capacities of 1C, 3C and 10C in application example 1 are higher than those in application example 5, the coating is uniform, the difference between the upper average film thickness and the lower average film thickness in a quartz boat/collecting box is only 0.07nm, the difference between the discharge capacities of 0.1C and the lower average film thickness is 0.8mAh/g, and application example 5 is not only up to 400nm, but also the coating is not uniform, and the difference between the upper average film thickness and the lower average film thickness in the quartz boat/collecting box is up to 0.29nm, so that the difference between the discharge capacities of 0.1C is up to 9.4mAh/g, thereby showing that the invention avoids secondary agglomeration of particles in a stacking state and the coating is more uniform, and the rate performance and stability performance of the battery are higher by adopting the integrated depolymerization and coating;
(3) As can be seen from the combination of application examples 1 and application examples 6 to 7, the temperature of the agglomerates in application example 1 was controlled to be 100 ℃ and the average particle size of the product in application example 1 was 300nm as compared with the temperatures in application examples 6 to 7 being controlled to be 30 ℃ and 180 ℃ respectively, and although the average particle sizes in application examples 6 to 7 were 330nm and 260nm respectively due to the presence of the screen, the 10C discharge capacities in application examples 6 to 7 were only 133.9mAh/g and 130.9mAh/g respectively, and the rate performance was lowered as compared with application example 1, thereby showing that the invention improves the rate performance of the nano-scale positive electrode material by optimizing the specific temperature range of the agglomerates in the collision depolymerization;
(4) As can be seen from the combination of application example 1 and comparative example 1, in application example 1, in a high-pressure jet depolymerization manner, compared with the crushing manner of the comparative example 1 by using a stirring crusher, the average particle diameter in application example 1 is as low as 300nm, and the average particle diameter in comparative example 1 is as high as more than 1 μm, and depolymerization of the cathode material is difficult to realize, wherein the 10C discharge capacity of comparative example 1 is only 128.6mAh/g, so that the invention is shown to remarkably improve the rate capability of the cathode material to prepare a battery by performing depolymerization by using the high-pressure jet manner and combining with CVD coating.
The detailed structural features of the present invention are described in the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope of the present invention and the scope of the disclosure.

Claims (40)

1. The preparation method of the depolymerization and coating integrated nanoscale cathode material is characterized by comprising the following steps of:
The aggregate of the anode material is respectively subjected to collision depolymerization by high-pressure injection from opposite directions, and after depolymerization, the sample is subjected to particle size screening under the action of a first air flow, is conveyed under the action of a second air flow and is coated by an organic film in a suspension state, so that the coated nanoscale anode material is obtained; the undeployed sample continues to undergo impact depolymerization under the influence of the first gas flow.
2. The method of claim 1, wherein the nanoscale positive electrode material comprises a phosphate-based positive electrode material.
3. The preparation method according to claim 1 or 2, wherein the preparation of the agglomerates comprises: and (3) roasting the precursor of the positive electrode material for one time to obtain an aggregate.
4. A method of preparation according to claim 3 wherein the agglomerates have a particle size of no more than 100 μm.
5. A method of preparation according to claim 3, wherein the primary calcination is carried out in a protective atmosphere.
6. The method of claim 5, wherein the protective atmosphere comprises nitrogen.
7. The method according to claim 3, wherein the primary baking temperature is 300-700 ℃.
8. The method according to claim 3, wherein the time of the primary baking is 4 to 30 hours.
9. The method according to claim 1 or 2, wherein the high-pressure injection pressure is in the range of 0.65 to 0.75mpa.
10. The method according to claim 1, wherein the particle density of the agglomerates in the high-pressure jet air stream is 25 to 100g/m 3 。
11. The method according to claim 1, wherein the temperature of the agglomerates during collision depolymerization is 60 to 160 ℃.
12. The method according to claim 1, wherein the organic film is coated by chemical vapor deposition.
13. The method according to claim 1, wherein the organic matter covered with the organic film comprises any one or a combination of at least two of paraffin, ethanol, polyethylene glycol, and polyvinylidene fluoride.
14. The production method according to claim 1 or 2, characterized in that the production method further comprises: and (3) carrying out secondary roasting on the coated nanoscale anode material to obtain a nanoscale anode material product.
15. The method of claim 14, wherein the secondary firing is performed in a protective atmosphere.
16. The method of claim 15, wherein the protective atmosphere comprises nitrogen.
17. The method according to claim 14, wherein the secondary baking temperature is 500-700 ℃.
18. The method according to claim 14, wherein the secondary baking time is 4 to 20 hours.
19. The method of preparation according to claim 1 or 2, characterized in that the collision deagglomeration is performed in a collision deagglomeration chamber.
20. The method according to claim 19, wherein the depolymerized sample is subjected to particle size screening under the action of a first air flow introduced from a first air flow inlet, enters a coating cavity, is conveyed to a coating area under the action of a second air flow introduced from a second air flow inlet, and is coated by an organic film, so as to obtain the coated nanoscale cathode material.
21. The method according to claim 20, wherein the depolymerized sample is subjected to particle size screening by the particle size screening means and then enters the coating chamber for organic film coating.
22. The method of claim 19, wherein the undeployed sample continues to undergo collisional depolymerization in the collisional depolymerization chamber under the influence of the first gas flow.
23. The method of claim 1, wherein the first gas stream flows from bottom to top.
24. The method of claim 1, wherein the first gas stream has a temperature of 90-190 ℃.
25. The method of manufacturing according to claim 1, wherein the first gas stream comprises a nitrogen gas stream.
26. The method of manufacturing according to claim 1, wherein the second gas stream comprises a nitrogen gas stream.
27. The preparation device of the depolymerization and coating integrated nanoscale anode material is characterized by comprising a coating cavity and a collision depolymerization cavity which are communicated from top to bottom; the collision depolymerization cavity is arranged at the lower part of one side of the cladding cavity;
the bottom of the collision depolymerization cavity is provided with a first gas inflow port; at least one group of opposite material inlets are arranged at the opposite positions of the side wall of the collision depolymerization cavity;
the material inlet is connected with a material conveying device which is a high-pressure pneumatic conveying device;
and one end of the cladding cavity, which is close to the collision depolymerization cavity, is provided with a second air flow inlet which is horizontally introduced.
28. The apparatus of claim 27, wherein the high pressure pneumatic conveying means comprises a material transfer box and an air compressor.
29. The apparatus according to claim 27, wherein an organic carbon source inlet is provided at an upper side of the coating chamber, and the organic carbon source inlet is provided at a side remote from the collision deagglomeration chamber.
30. The apparatus of claim 27, wherein an exhaust pipe is disposed within the cladding chamber.
31. The manufacturing apparatus of claim 30, wherein the exhaust pipe extends into a lower portion of the cladding cavity.
32. The apparatus according to claim 27, wherein a particle size screening means is provided between the coating chamber and the collision deagglomeration chamber.
33. The apparatus of claim 32, wherein the particle size screening means comprises a screen.
34. The apparatus according to claim 32, wherein a gas injection port is provided above the particle size screening member, and the gas injection port is connected to a gas delivery device.
35. The apparatus according to claim 27, further comprising a collecting member provided at a lower side of the covering chamber.
36. The manufacturing apparatus of claim 35 wherein the collection means comprises a collection tank.
37. The apparatus of claim 36, wherein the collection tank is provided with an exhaust port.
38. The apparatus according to claim 35, wherein the collecting member is provided at a lower side corresponding to the organic carbon source inlet.
39. A nanoscale positive electrode material, characterized in that the preparation method of the depolymerization and coating integrated nanoscale positive electrode material is adopted.
40. A lithium ion battery comprising the nanoscale positive electrode material of claim 39.
CN202210108299.7A 2022-01-28 2022-01-28 Nanoscale positive electrode material, preparation method and preparation device thereof and lithium ion battery Active CN114497548B (en)

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