WO2020078444A1

WO2020078444A1 - Method and device for producing nano-scale clad material

Info

Publication number: WO2020078444A1
Application number: PCT/CN2019/111810
Authority: WO
Inventors: 邱新平; 张文广
Original assignee: 清华大学; 北京清创硅谷科技有限公司
Priority date: 2018-10-19
Filing date: 2019-10-18
Publication date: 2020-04-23
Also published as: CN111072051A; CN111072051B

Abstract

Disclosed are a method and device for producing a nano-scale clad material. The method comprising: steps 1-3: conducting preheating to make a core material, precursors of a housing material and fluidized gas reach different temperatures; steps 4-6: adding the preheated raw material and fluidized gas to a reactor (1) for reaction, and feeding a reaction mixture into a first cyclone separator (2) and a second cyclone separator (3) sequentially, such that gas substances and solid substances respectively return to the reactor (1) through circulation pipelines; and step 7: discharging the generated uniform and compact clad material under the action of the fluidized gas. The reaction mixture flows among the reactor (1), the first cyclone separator (2), and the second cyclone separator (3) under the action of the fluidized gas and is dispersed uniformly, such that the problem of nano-particles tending to agglomerate is solved. In the above reaction, the thickness and compactness of the clad material can be accurately controlled by controlling circulation time, such that the physical property of the material can be accurately controlled.

Description

Method and device for producing nano-coated material

Technical field

The present disclosure relates to a method and device for producing nano-coated materials. In particular, the present disclosure particularly relates to a method and device for mass production of nano-clad materials for electrodes of electrochemical devices, and in particular to a method and device for mass production of nano-silicon materials for electrochemical devices.

Background technique

In the field of lithium ion batteries, in order to increase energy density, it is necessary to develop electrode materials with high specific capacities. The anode material used in the existing commercial lithium-ion battery is graphite, and the actual specific capacity is close to the theoretical limit, and finding a new high-capacity anode material has become an urgent problem to be solved.

Among the many choices of anode materials, silicon materials have the highest theoretical specific capacity, and are widely concerned and valued by R & D workers. There have been many reports on the research of nano-silicon particles and composite materials, but they have not solved the problem of thickening of the solid electrolyte interface film (SEI film); the silicon material with nano-hollow structure proposed by the Chinese patent application with the publication number CN105705460A It can solve the SEI film thickening, but it is still at the laboratory preparation level (gram level: g / time).

Therefore, there is still a need for a commercially available method and device for mass production of nano-coated materials.

Summary of the invention

Therefore, an object of the present disclosure is to provide a method for producing nano-clad materials.

An object of the present disclosure is to provide a device for producing nano-coated materials.

According to an embodiment of the present disclosure, it provides a method of producing a nano-clad material, the method including:

The first step: the temperature of the nuclear material reaches the first temperature by preheating;

The second step: the temperature of the precursor of the shell material reaches the second temperature by preheating;

The third step: the temperature of the fluidizing gas reaches the third temperature through preheating;

Where, when the reaction temperature of the precursor of the shell material is T ₀ , the first temperature is T ₀ + 100 ° C to T ₀ + 150 ° C,

The second temperature is T ₀ -100 ° C to T ₀ -50 ° C,

The third temperature is T ₀ -50 ° C to T ₀ + 150 ° C;

The fourth step: adding the preheated core material to the reactor, and continuously feeding the fluidizing gas and the precursor of the shell material so that the precursor of the shell material reacts on the surface of the core material to generate the coating material, while , At least part of the reacted first mixture containing the generated coating material moves to the first cyclone separator under the action of the air flow;

Fifth step: At least part of the first mixture moved to the first cyclone separator in the fourth step is separated therein, wherein at least part of the solid material of the generated coating material and unreacted nuclear material is in the first Settling in the cyclone separator, heated again, and then returned to the reactor, at least part of the second mixture treated in the first cyclone separator is sent to the second cyclone separator;

Sixth step: In the fifth step, at least part of the solid matter of the second mixture sent to the second cyclone settles in it and is heated again, and then returns to the reactor and is sent to the second After filtering at least part of the gaseous substance of the second mixture of the cyclone separator, it is returned to the circulation gas inlet of the reactor through the circulation line,

Seventh step: The generated coating material is discharged through the outlet of the reactor.

In some embodiments of the present disclosure, in the seventh step, when the generated coating material satisfies a predetermined condition, the generated coating material is discharged under the action of the air flow;

The predetermined condition is, for example, that the thickness of the cladding layer reaches 10-30 nm or more.

Before performing the seventh step, the circulation of the reaction mixture in the fourth step, the fifth step, and the sixth step is performed at least twice.

In some embodiments of the present disclosure, in the sixth step, at least part of the gaseous substance of the filtered second mixture is pressurized on the circulation line.

In some embodiments of the present disclosure, the fourth to sixth steps are repeatedly performed, and

The fourth step includes: without evacuating the reactor, adding new nuclear material heated to the first temperature to the reactor for continuous production.

In some embodiments of the present disclosure, in this method: the core material may or may not participate in the reaction; the shell material may be obtained by a decomposition reaction of a single precursor, or may be reacted by two or more precursors get.

In some embodiments of the present disclosure, the temperature of the reactor wall is controlled below the reaction temperature of the shell material precursor to prevent the shell material precursor from reacting on the reactor wall, thereby preventing reactor fouling.

In the method for preparing the coating material described above, in some embodiments of the present disclosure, the particle diameter of the core material is 1 nm to 1 μm, 10 nm to 200 nm, or 30 nm to 80 nm.

In some embodiments of the present disclosure, in order to obtain a shell material with a thickness of 10-30 nm, the time for flowing the fluidizing gas is 0.5h-5h, and the fluidizing gas rate is 5L / min · cm ² -25L / min · Cm ² ; the time to pass into the shell material precursor is 0.1h-3h, and the rate of the precursor is 0.2L / min · cm ² -1.5L / min · cm ² .

The fluidizing gas is any suitable gas that does not react with the core material and / or the precursor of the shell material and / or the shell material under the temperature / pressure conditions in the reactor, in this disclosure In some embodiments, the fluidizing gas initially introduced (that is, before the gas generated during the reaction has not been recycled as the fluidizing gas) may be an inert gas. The fluidizing gas may also be nitrogen.

In some embodiments of the present disclosure, the core material is a metal carbonate of nanometer or micrometer scale, and the precursor of the shell material refers to a compound or mixture including silicon-containing elements, including: silane, trichlorosilane , Silicon dichloride, silicon tetrachloride, and at least one or a combination of their mixtures with hydrogen.

In some embodiments of the present disclosure, the core material refers to metal carbonate, including at least one of lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate, or a combination thereof, as long as the particle size of the core material is ensured The distribution can be sufficiently uniform, and the particle size is between 10 nm and 200 nm.

In some embodiments of the present disclosure, the shell material precursor is selected from silane, the initial fluidizing gas is selected from nitrogen or argon, the temperature of the original silane gas after preheating is controlled between 300 ° C and 350 ° C, and the initial fluidization The temperature of the gas is controlled between 400 ° C and 500 ° C.

In some embodiments of the present disclosure, the temperature of the metal carbonate is between 410 ° C and 850 ° C, preferably between 450 ° C and 550 ° C.

When the silane gas is in contact with the carbonate, heat exchange is performed immediately, so that the temperature of the silane gas reaches the decomposition temperature in a short time, thereby forming a coating layer. When the temperature of the pre-heated silane gas is higher than 400 ° C, it may cause the silane to decompose earlier and generate solid silicon particles.

According to another aspect of the present disclosure, it provides a device for preparing a nano-clad material, the cladding material cladding a shell material on the surface of a core material, characterized in that the device includes:

The reactor includes a first inlet, a first inlet, a second inlet, a third inlet, a first outlet, a first outlet, and a second inlet, the first inlet The material port is located above the first air inlet, the second air inlet and the third air inlet;

A first cyclone separator, which includes a fourth air inlet, a second outlet, a third outlet, and a filter device, the fourth air inlet is connected to the first outlet of the reactor, the filter device is provided in the State the third exit;

A second cyclone separator, which includes a fifth air inlet, a fourth outlet, a fifth outlet, and a filtering device, the fifth air inlet is connected to a third outlet of the first cyclone, the filtering device Set at the fifth exit;

The filtering device of the first cyclone and the filtering device of the second cyclone are respectively provided at the third outlet of the first cyclone and the fifth outlet of the second cyclone,

A first circulation line connecting the fifth outlet of the second cyclone and the third air inlet of the reactor,

A second circulation line connected to the second inlet of the reactor, the second outlet of the first cyclone, and the fourth outlet of the second cyclone,

A heating device provided on at least part of the first cyclone separator, the second cyclone separator, and the lower circulation line.

In some embodiments of the present disclosure, the device further includes a gas boosting device, the gas boosting device is located on the first circulation line, such that the first circulation line is connected to the The fifth outlet of the second cyclone and the third air inlet of the reactor.

In some embodiments of the present disclosure, the reactor further includes a gas distribution plate, and the gas distribution plate is disposed at the bottom of the reactor;

In some embodiments of the present disclosure, the first air inlet is located above the gas distribution plate, and the second air inlet and the third air inlet are located below the gas distribution plate.

The preparation device of the particulate material according to the present disclosure may further include pipes, valves, pumps, flow meters, thermometers, pressure gauges, raw material tanks, and other components conventionally used in the art, and their structures and functions are the same as in the prior art. This will not be repeated here.

In the above method according to the present disclosure, the precursor of the shell material in contact with the fluidized core material in the reactor will preferentially decompose on the surface of the core material to form the shell material after reaching the reaction temperature, rather than in the gas itself. Nucleation (this “nucleation” refers to the formation of crystal nuclei, which is not the same concept as the nuclei of the aforementioned “nuclear material”) and crystallization, whereby a uniform coating material of fine particles can be obtained.

Beneficial effect

The reaction mixture of the present disclosure is circulated and uniformly dispersed between the reactor, the first cyclone separator, and the second cyclone separator under the action of the fluidizing gas, which solves the problem that the nano particles are easily agglomerated during the transportation process. In the reaction of the present disclosure, the thickness and density of the coating material can be accurately controlled by controlling the cycle time, so that the physical properties of the material can be accurately controlled.

In addition, by accurately controlling the temperature of the core material, the precursor of the shell material, and the inner wall of the reactor, the precursor of the shell material can be generated only on the surface of the core material, avoiding the problem of reactor fouling.

In the reaction process of the present disclosure, since the temperature of the reactants is controlled separately, the second batch of preheated nuclear materials can be directly introduced after the reactants are discharged, so that there is almost no need to adjust the atmosphere and temperature of the reactor, so as to achieve Continuous production of different batches.

By introducing a gas pressurizing device, the gas in the reaction mixture can be smoothly returned to the reactor through the circulation line without causing counterflow.

BRIEF DESCRIPTION

FIG. 1 is a flowchart of a method according to an embodiment of the present invention.

2 is a schematic diagram of a reaction device according to an embodiment of the present invention.

3 is a schematic diagram of a reaction device according to another embodiment of the present invention.

4 and 5 are a scanning electron microscope photograph and a transmission electron microscope photograph of hollow silicon particles prepared according to an embodiment of the present invention.

6 is a graph of the cycle performance of a battery including the hollow silicon particles of the present invention prepared according to an embodiment of the present invention.

7 is a scanning electron micrograph of hollow silicon particles prepared according to another embodiment of the present invention.

8 is a schematic diagram of a reaction device according to yet another embodiment of the present invention.

detailed description

In order to enable those with ordinary knowledge in the art to understand the features and effects of the present invention, the following is a general description and definition of the terms and terms mentioned in the description and patent application. Unless otherwise specified, all technical and scientific words used in the text have the usual meanings understood by those skilled in the art to the present invention. In case of conflict, the definition in this specification shall prevail.

In this article, the terms "include", "include", "have", "contain" or any other similar terms are open-ended transitional phrases, which are intended to cover non-exclusive inclusions. For example, a composition or article containing a plurality of elements is not limited to those listed herein, but may also include other elements that are not explicitly listed but are generally inherent to the composition or article. In addition, unless explicitly stated to the contrary, the term "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following conditions satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), Both A and B are true (or exist). In addition, in this article, the interpretation of the terms "including", "including", "having" and "containing" shall be deemed to have been specifically disclosed and cover both "consisting of" and "substantially consisting of" Or semi-closed conjunctions.

In this article, unless otherwise stated, "first", "second", etc. are only used to distinguish different units, steps, etc., and do not limit their order. Without departing from the gist of the invention, they Can be replaced.

In this article, all the features or conditions defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values within the ranges, especially integer numerical values. For example, the range description of "1 to 8" should be considered as having specifically disclosed all sub-ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., in particular It is a sub-range defined by all integer values, and should be regarded as individual values within 1, 2, 3, 4, 5, 6, 7, 8 etc. that have been specifically disclosed. Unless otherwise specified, the foregoing interpretation method is applicable to all contents of the entire text of the present invention, regardless of its broad scope.

If a quantity or other numerical value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that the upper limit or preferred value of the range and the lower limit of the range have been specifically disclosed herein Or all ranges formed by the preferred values, regardless of whether these ranges are disclosed separately. In addition, when a range of values is mentioned herein, unless otherwise stated, the range should include the endpoints and all integers and fractions within the range.

Herein, on the premise that the purpose of the invention can be achieved, the numerical value should be understood as having the accuracy of the effective number of digits of the numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

The following specific embodiments are merely exemplary in nature, and are not intended to limit the present invention and its uses. In addition, this document is not limited by any theory described in the foregoing prior art or content of the invention or the following specific embodiments or examples.

As shown in FIG. 1, the method for producing a nano-clad material according to an embodiment of the present disclosure may include:

The second temperature is T ₀ -100 ° C to T ₀ -50 ° C,

The third temperature is T ₀ -50 ° C to T ₀ + 150 ° C;

In the above method, the first and second cyclone separators can fully disperse the coating material to be generated, thereby obtaining a product with a small particle size and a uniform dispersion.

According to an embodiment of the present disclosure, in the seventh step, when the generated coating material satisfies a predetermined condition, the generated coating material is discharged under the action of the air flow; before the seventh step is performed, The circulation of the reaction mixture in the fourth step, the fifth step and the sixth step is performed at least twice. The predetermined condition is, for example, that the thickness of the cladding layer reaches 10-30 nm or more, and it can be preset according to the requirements for the cladding layer in actual processing, thereby directly obtaining the cladding material that meets the processing requirements. In the above method, by performing the above steps cyclically, for example, at least twice, a densely coated coating material can be obtained.

According to an embodiment of the present disclosure, in the sixth step, at least part of the gaseous substance of the filtered second mixture is pressurized on the circulation line. By pressurizing, the pressure in each container can be more effectively controlled, thereby controlling the flow direction of solid products and gaseous products, which is beneficial to the generation of coating materials.

According to an embodiment of the present disclosure, the fourth step to the sixth step are repeatedly performed, and the fourth step includes: new nuclear material to be heated to the first temperature without emptying the reactor Add to the reactor for continuous production. In this way, the waste of energy and carrier gas due to repeated changes in the atmosphere and temperature in the reactor can be greatly reduced.

According to an embodiment of the present disclosure, in this method: the core material can participate in or not participate in the reaction; the shell material can be obtained from the decomposition reaction of a single precursor, or can be obtained from the reaction between two or more precursors .

According to an embodiment of the present disclosure, the method further includes controlling the temperature of the wall of the reactor below the reaction temperature of the precursor of the shell material. In this way, it is possible to prevent the precursor of the shell material from reacting on the reactor wall to cause fouling of the reactor.

According to an embodiment of the present disclosure, the particle size of the core material is between 1 nm and 1 μm.

When the particle size of the core material is within this range, the resulting coating material has moderate activity, that is, it can be used more advantageously for subsequent applications and can reduce the generation of particle agglomeration.

According to one embodiment of the present disclosure, the time for flowing fluidizing gas is 0.5h-5h, and the rate of the fluidizing gas is 5L / min · cm ² -25L / min · cm ² ; It is 0.1h-3h, and the rate of the precursor is 0.2L / min · cm ² -1.5L / min · cm ² .

Using the above process can effectively obtain a uniform and dense coating material.

According to an embodiment of the present disclosure, the fluidizing gas is an inert gas or nitrogen, the core material is a nano- or micro-scale metal carbonate, and the precursor of the shell material is selected from silane, trichlorosilane, At least one or a combination of silicon dichloride, silicon tetrachloride, and their mixture with hydrogen.

According to an embodiment of the present disclosure, the core material includes at least one of lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate, or a combination thereof, and the particle size is between 10 nm and 200 nm, and the shell material The precursor is silane, and the fluidizing gas is nitrogen or argon. The temperature of the original silane gas after preheating is controlled between 300 ° C and 350 ° C, and the temperature of the initial fluidizing gas is controlled between 400 ° C and 500 ° C. The temperature of the metal carbonate is between 410 ° C and 850 ° C.

Using the above-mentioned materials can effectively obtain a coating material that can be used for an electrode of a lithium ion battery.

As shown in FIG. 2, the apparatus for preparing a nano-clad material according to an embodiment of the present disclosure may include:

Reactor 1, which includes a first feed port 10, a first gas inlet 11, a second gas inlet 12, a third gas inlet 13, a first outlet 14, a first outlet 15 and a second feed Port 16, the first feed port 10 is located above the first air inlet 11, the second air inlet 12, and the third air inlet 13;

The first cyclone 2 includes a fourth air inlet 21, a second outlet 22, a third outlet 23, and a filtering device 24, the fourth air inlet 21 is connected to the first outlet 15 of the reactor 1 , The filtering device 24 is provided at the third outlet 23;

The second cyclone 3 includes a fifth air inlet 31, a fourth outlet 32, a fifth outlet 33 and a filter device 34, the fifth air inlet 31 is connected to the third of the first cyclone Outlet 23, the filtering device 34 is provided at the fifth outlet 33;

A first circulation line 4, the first circulation line 4 connects the fifth outlet 33 of the second cyclone and the third air inlet 13 of the reactor 1;

The second circulation line 5 is connected to the second feed port 16 of the reactor 1, the second outlet 22 of the first cyclone 2 and the second cyclone 3's fourth exit 32;

The heating device 7 is provided on at least part of the first cyclone 2, the second cyclone 3 and the lower circulation line 5.

According to the above preparation device, the first and second cyclone separators can fully disperse the coating material to be generated, thereby obtaining a product with small particle size and uniform dispersion.

According to an embodiment of the present disclosure, the device further includes a gas pressurizing device 8 that is located on the first circulation line 4.

The gas pressurizing device can more effectively control the pressure in each container, thereby controlling the flow direction of solid products and gaseous products, which is beneficial to the generation of coating materials.

According to an embodiment of the present disclosure, the reactor 1 further includes a gas distribution plate 17 that is disposed at the bottom of the reactor 1. The gas distribution plate can effectively disperse the raw materials, fluidizing gas, circulating gas and other gases entering the preparation device.

According to an embodiment of the present disclosure, the first air inlet 11 is located above the gas distribution plate 17, and the second air inlet 12 and the third air inlet 13 are located below the gas distribution plate 17. Due to the pressure difference between the upper and lower sides of the gas distribution plate, through the above settings, the pressure distribution in each container can be controlled more accurately, thereby controlling the gas flow direction.

With the preparation device of FIG. 3, the specific process implemented may have the following flow.

The solid core material preheated to the first temperature (higher than the reaction temperature of the precursor of the shell material) is added to the reactor through the first feed port 10 of the reactor 1, and preheated to the third temperature (higher than the shell material) The reaction temperature of the precursor of the precursor) is added to the reactor through the second gas inlet 12 of the reactor 1, the fluidized gas is evenly distributed under the action of the gas distribution plate 17, and the solid nuclear material is fluidized and maintained The temperature is higher than the reaction temperature of the precursor of the shell material. The precursor of the shell material preheated to the second temperature (lower than the reaction temperature of the precursor of the shell material) is added to the reactor through the first gas inlet 11 of the reactor 1, so that the precursor is on the surface of the core material Reaction to obtain core-shell structured nano-coated particles.

The reaction mixture is sent to the first cyclone separator 2 through the first outlet of the reactor 1 under the action of fluidizing gas. In the first cyclone separator 2, most of the solid particles settle and pass through the second circulation line 5 The second feed port of the reactor 1 returns to the reactor 1, and most of the gas and a small amount of fine solid particles are sent to the second cyclone 3 through the filtering device 24 of the first cyclone 2.

In the second cyclone 3, the mixture is further separated, the solid particles settle and return to the reactor 1 from the second feed port of the reactor 1 via the second circulation line 5, and the gas component passes through the second cyclone 2 The filtering device 34 is sent to the third gas inlet of the reactor 1 through the first circulation line, and is sent into the reactor 1 through the gas distribution plate 17 together with the fluidizing gas.

Thus, the reaction mixture circulates in the reactor, the first cyclone separator, and the second cyclone separator and gradually reacts to form a uniform and dense coating material. After a predetermined time, the coating material passes through the reactor 1 The first discharge port 14 is discharged under the action of the air flow.

Although FIG. 2 and FIG. 3 show an exemplary structure of the preparation device of the present invention, those skilled in the art can understand that the positions of components of these devices are not limited by the specific structure.

Specifically, in FIG. 2, the lower air inlet 11 of the precursor for feeding the preheated shell material is below the gas distribution plate 17 and communicates with the bottom air inlet 12 and the bypass circulation air inlet 13 . However, the lower gas inlet can also be provided at other positions in the lower part of the reactor 1.

For example, as shown in FIG. 8, the lower air inlet 11 of the precursor of the shell material is provided above the gas distribution plate, and one is provided at each symmetrical position. The air inlet can also be evenly arranged on the outer circumference of the reactor at the same height.

The other components of FIG. 8 are the same as the connection relationship of FIG. 1 and will not be repeated here.

Examples

The present invention will be described below through specific examples. Those skilled in the art can understand that the following embodiments are for illustrative purposes only, and do not limit the scope of the present invention in any way.

Example 1

In the device shown in Figure 1, nano-calcium carbonate particles are used as the core material, after preheating it to 500 ° C, it is added to the reactor through the upper feed port 10 of the reactor, and the temperature of the reactor wall is maintained at 350 ° C .

Nitrogen was used as the fluidizing gas, which was preheated to 390 ° C, passed through the gas inlet 12 at the bottom of the reactor 1, passed through the gas distribution plate 17, and evenly dispersed into the reactor 1 to fluidize the solid calcium carbonate.

The silane (SiH ₄ ) as the precursor of the shell material is preheated to 350 ° C. and then introduced into the reactor 1 through the gas inlet plate 11 of the lower inlet of the reactor 1 through the gas distribution plate 17. , It will decompose on its surface to form a coated silicon layer. The fluidized reaction mixture is sent together to the first cyclone 2 under the action of a high-speed gas flow.

In the first cyclone separator 2, most of the solid particles in the mixture settle and return to the reactor 1 through the lower circulation line, and the gas and a small amount of nanoparticles are sent to the second cyclone separator 3 through the filter device 24 Inside.

In the second cyclone 3, the mixture is further separated, the solid particles settle and return to the reactor 1 through the lower circulation line, and the gas passes through the filter device 34 and returns to the reaction through the gas pressurization device 8 through the upper circulation line 4 Reactor 1 circulates.

A heating device 7 is provided on the first cyclone 2, the second cyclone 3, and the lower circulation line to heat the settled nanoparticles to 500 ° C again.

After 60 minutes of reaction, a uniform and dense silicon layer was formed on the surface of the nano-calcium carbonate particles with multiple cycles. At this time, the bottom outlet 14 of the reactor 1 was opened to discharge the product.

After the product is discharged, the bottom outlet 14 of the reactor 1 is closed, and a new batch of nano-calcium carbonate particles is thrown in, so that continuous production can be performed without changing the state of the reactor.

Experimental Example 1

The coating material prepared in Example 1 was placed in a reaction kettle and reacted with 8% wt dilute hydrochloric acid for 4h, then washed with ethanol, centrifuged, and dried to obtain nanometer-sized hollow silicon particles. As shown in Figure 2, Figure 3.

The prepared hollow silicon material, conductive carbon black, binder sodium carboxymethylcellulose (CMC) and graphite are mixed evenly according to the mass ratio of 10: 2: 4: 84, and deionized water is used as a solvent to disperse it uniformly. The negative electrode slurry was obtained, then coated on copper foil, and dried under vacuum at 100 ° C for 24 hours to obtain pole pieces.

Using analytically pure metal lithium sheet as counter electrode, together with the pole piece prepared above, 1M LiPF6 ethylene carbonate (EC) / dimethyl carbonate (DMC) (volume ratio is 1: 1) solution as conductive medium , Using Celgard-2320 (microporous polypropylene film) as the battery separator to assemble CR2025 button cell, the assembly process was carried out in a glove box filled with argon gas. The button battery was subjected to a capacity cycle test at a current density of 140 mA / g, and the capacity was stable at 696 mAh / g, and the capacity decayed little after 100 cycles, as shown in FIG. 4.

Example 2

Except that the reaction time was changed from 60 min to 30 min, it was prepared in the same manner as in Example 1 to obtain a nano-clad material.

Experimental Example 2

The coating material prepared in Example 2 was placed in a reaction kettle and reacted with 8% wt dilute hydrochloric acid for 4h, then washed with ethanol, centrifuged, and dried to obtain nano-sized hollow silicon particles. The scanning electron micrograph is shown in Figure 5. .

It can be seen from the comparison between Fig. 3 and Fig. 5 that the wall thickness of the nano-hollow silicon in Fig. 3 is about 30 nm, and the wall thickness of the nano-hollow silicon in Fig. 5 is about 16 nm. Therefore, the thickness of the nano-hollow silicon wall can be effectively adjusted by controlling the time for the introduction of silane gas.

Example 3

As shown in FIG. 8, the position of the SiH ₄ gas inlet 11 in the reactor 1 is changed, that is, the SiH ₄ gas inlet is designed above the gas distribution plate, and one is provided at each symmetrical position. Except for replacing the device shown in FIG. 1 with the device shown in FIG. 8, the reaction was performed according to the procedure of Example 1 to obtain a nano-clad material.

Compared with Example 1, after the SiH ₄ gas inlet is changed, the temperature adjustment range of the circulating fluidized gas fed from the gas inlet of the bottom 12 of the reactor 1 is larger. The calcium carbonate powder can be heated by increasing the temperature of the circulating fluidizing gas, while avoiding the decomposition of the SiH ₄ gas before the powder is in contact with the powder due to the heating of the circulating gas above T ₀ .

The above-mentioned embodiments are merely auxiliary explanations in nature, and are not intended to limit the examples of applications or the applications or uses of these examples. In this article, the term "exemplary" means "as an example, example, or illustration". Any one of the exemplary embodiments herein is not necessarily interpreted as preferred or more advantageous than other embodiments.

In addition, although at least one illustrative example or comparative example has been proposed in the foregoing embodiments, it should be understood that the present invention may still have a large number of changes. It should also be understood that the embodiments described herein are not intended to limit the scope, use, or configuration of the requested application target in any way. On the contrary, the foregoing embodiments will provide a simple guide for those of ordinary skill in the art to implement one or more of the described embodiments. Furthermore, various changes can be made to the function and arrangement of elements without departing from the scope defined by the scope of patent application, and the scope of patent application includes known equivalents and all foreseeable equivalents at the time of filing the application .

Claims

A method for producing nano-coated materials, characterized in that the method includes:

The first step: the temperature of the nuclear material reaches the first temperature by preheating;

The second step: the temperature of the precursor of the shell material reaches the second temperature by preheating;

The third step: the temperature of the fluidizing gas reaches the third temperature through preheating;

Where, when the reaction temperature of the precursor of the shell material is T 0 , the first temperature is T 0 + 100 ° C to T 0 + 150 ° C,

The second temperature is T 0 -100 ° C to T 0 -50 ° C,

The third temperature is T 0 -50 ° C to T 0 + 150 ° C;

The fourth step: adding the preheated core material to the reactor, and continuously feeding the fluidizing gas and the precursor of the shell material so that the precursor of the shell material reacts on the surface of the core material to generate the coating material, while , At least part of the reacted first mixture containing the generated coating material moves to the first cyclone separator under the action of the air flow;

Fifth step: At least part of the first mixture moved to the first cyclone separator in the fourth step is separated therein, wherein at least part of the solid material of the generated coating material and unreacted nuclear material is in the first Settling in the cyclone separator, heated again, and then returned to the reactor, at least part of the second mixture treated in the first cyclone separator is sent to the second cyclone separator;

Sixth step: In the fifth step, at least part of the solid matter of the second mixture sent to the second cyclone settles in it and is heated again, and then returns to the reactor and is sent to the second After filtering at least part of the gaseous substance of the second mixture of the cyclone separator, it is returned to the circulation gas inlet of the reactor through the circulation line,

Seventh step: The generated coating material is discharged through the outlet of the reactor.
The method of claim 1, wherein:

In the seventh step, when the generated coating material satisfies a predetermined condition, the generated coating material is discharged under the action of the air flow;

Before performing the seventh step, the circulation of the reaction mixture in the fourth step, the fifth step, and the sixth step is performed at least twice.
The method of claim 1, wherein:

In the sixth step, at least part of the gaseous substance of the filtered second mixture is pressurized on the circulation line.
The method of claim 1, wherein:

The fourth step to the sixth step are repeatedly performed, and

The fourth step includes: without evacuating the reactor, adding new nuclear material heated to the first temperature to the reactor for continuous production.
The method according to claim 1, wherein in the method:

The core material can participate or not participate in the reaction; the shell material can be obtained by a decomposition reaction of a single precursor, or can be obtained by reacting two or more precursors with each other.
The method according to claim 1, further comprising: controlling the temperature of the wall of the reactor below the reaction temperature of the precursor of the shell material.
The method according to claim 1, wherein the particle size of the core material is between 1 nm and 1 μm.
The method according to claim 1, characterized in that the time for introducing fluidizing gas is 0.5h-5h, and the rate of the fluidizing gas is 5L / min · cm 2 -25L / min · cm 2 ; The time of the material precursor is 0.1h-3h, and the rate of the precursor is 0.2L / min · cm 2 -1.5L / min · cm 2 .
The method according to claim 1, wherein the fluidizing gas is an inert gas or nitrogen,

The core material is nano- or micro-scale metal carbonate,

The precursor of the shell material is selected from at least one or a combination of silane, trichlorosilane, dichlorosilane, silicon tetrachloride, and a mixture thereof with hydrogen.
The method according to claim 1, wherein the core material comprises at least one of lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate, or a combination thereof, and the particle size is between 10 nm and 200 nm ,

The precursor of the shell material is silane, the fluidizing gas is nitrogen or argon, the temperature of the original silane gas after preheating is controlled between 300 ° C and 350 ° C, and the temperature of the initial fluidizing gas is controlled between 400 ° C and 500 The temperature of the metal carbonate is between 410 ° C and 850 ° C.
A device for producing nano-coated material, the coating material is coated with a shell material on the surface of the core material, and is characterized in that the device includes:

Reactor (1), which includes a first inlet (10), a first inlet (11), a second inlet (12), a third inlet (13), and a first outlet ( 14), a first outlet (15) and a second inlet (16), the first inlet (10) is located in the first inlet (11), the second inlet (12) and Above the third air inlet (13);

The first cyclone separator (2) includes a fourth air inlet (21), a second outlet (22), a third outlet (23) and a filtering device (24), the fourth air inlet (21) Connected to the first outlet (15) of the reactor (1), the filtering device (24) is provided at the third outlet (23);

The second cyclone separator (3) includes a fifth air inlet (31), a fourth outlet (32), a fifth outlet (33) and a filtering device (34), the fifth air inlet (31) Connected to the third outlet (23) of the first cyclone, the filtering device (34) is provided at the fifth outlet (33);

A first circulation line (4), the first circulation line (4) connecting the fifth outlet (33) of the second cyclone and the third air inlet (13) of the reactor (1) );

A second circulation line (5) connected to the second feed port (16) of the reactor (1) and the second of the first cyclone (2) An outlet (22) and a fourth outlet (32) of the second cyclone separator (3);

A heating device (7) provided on at least part of the first cyclone separator (2), the second cyclone separator (3) and the lower circulation line (5).
The device according to claim 11, characterized in that

The device further includes a gas pressurizing device (8), which is located on the first circulation line (4).
The device according to claim 11, characterized in that

The reactor (1) further includes a gas distribution plate (17), and the gas distribution plate (17) is disposed at the bottom of the reactor (1).
The device according to claim 13, characterized in that

The first inlet (11) is located above the gas distribution plate (17), and the second inlet (12) and the third inlet (13) are located on the gas distribution plate (17) Below.