CN112703051A

CN112703051A - Micro-channel reactor and method for preparing precursor micro-nano particles of lithium battery anode material and cathode material

Info

Publication number: CN112703051A
Application number: CN201980009425.XA
Authority: CN
Inventors: 于志远; 佘玥欣; 刘于航
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2021-04-23
Anticipated expiration: 2039-08-22
Also published as: CN112703051B; WO2021031201A1

Abstract

A microchannel reactor, comprising: the upper sealing plate (1), the first substrate (2), the second substrate (3) and the lower sealing plate (4) are sequentially attached from top to bottom; a first feeding main channel and a first feeding branch channel are formed between the upper sealing plate (1) and the first base plate (2); one end of the feeding branch channel I is communicated with the feeding main channel I, and the other end of the feeding branch channel I is closed; a second feeding main channel and a second feeding branch channel are formed between the second base plate (3) and the lower sealing plate (4); the through hole (2-3) is communicated with the feeding branch channel I and the feeding branch channel II; one end of the feeding branch channel II is communicated with the feeding main channel II, and the other end of the feeding branch channel II extends to the outer edge of the substrate II (3). The microchannel reactor can be used for preparing metal and metal compound particles with uniform and controllable particle size and shape or metal and metal compound particles coated by other materials.

Description

Micro-channel reactor and method for preparing precursor micro-nano particles of lithium battery anode material and cathode material

Technical Field

The invention relates to the technical field of chemistry and chemical engineering, in particular to a microchannel reactor and a method for preparing precursor micro-nano particles of a lithium battery anode material and a lithium battery cathode material.

Background

In recent years, global energy and environmental protection awareness is rising, and electric vehicles are promoted by most countries, so that the market of the global electric vehicles is developed vigorously. The lithium battery mainly comprises a positive electrode material, a negative electrode material, a diaphragm, an electrolyte and a battery shell. The positive electrode material and the negative electrode material are decisive factors of the electrochemical performance of the lithium battery, directly determine the energy density and the safety of the battery, and further influence the comprehensive performance of the battery.

The lithium battery positive electrode material mainly comprises ternary materials (NCM and NCA), lithium iron phosphate (LFP), Lithium Cobaltate (LCO) and Lithium Manganate (LMO), and the four materials are applied to different markets due to respective characteristic differences. Under the rapid growth of power batteries for vehicles, batteries for electric tools, batteries for electric bicycles and the like and the influence of low cobalt of 3C batteries, the NCM ternary cathode material has replaced lithium iron phosphate in 2017 and becomes the largest lithium battery cathode material in China.

The precursor of the ternary cathode material directly determines the core physical and chemical properties of the ternary cathode material. The ternary precursor is a key material for producing the ternary cathode, is prepared into the ternary cathode by mixing and sintering with a lithium source, and the core physical and chemical properties of the ternary cathode material are directly determined by the properties, and are specifically represented as follows: 1) precursor impurities can be brought into the anode material to influence the content of the anode impurities; 2) the particle size and the particle size distribution of the precursor directly determine the particle size and the particle size distribution of the ternary positive electrode; 3) the specific surface area and the morphology of the ternary precursor directly determine the specific surface area and the morphology of the ternary anode; 4) the proportion of the ternary precursor elements directly determines the proportion of the ternary anode elements and the like. The physicochemical properties of the ternary positive electrode, such as particle size, morphology, element proportion, impurity content and the like, influence the core electrochemical properties of the lithium battery, such as energy density, rate capability, cycle life and the like. In addition, the application and popularization of the novel anode material such as the ternary anode with the gradient and core-shell structure depend on the research and development breakthrough of the corresponding precursor.

The common ternary cathode material has limitations. The common ternary anode is spherical or quasi-spherical secondary particles formed by aggregating primary single crystal particles, is formed by combining a plurality of particles, and has wider particle size distribution. The main defects are as follows: (1) poor fastness: the structural firmness of the secondary ball is poor, the compaction density is generally 3.4g/cm 3-3.7 g/cm3, and under high compaction, the secondary ball is broken, so that particles in the material are exposed, side reactions are increased, metal ions are dissolved out rapidly, and the electrical performance is reduced; (2) the structural defects are many: the primary particle diameters of the inside and the outside of the secondary ball are small, the structural defects are many, and structural collapse is easy to occur under the high-voltage charging and discharging conditions; (3) the coating property is poor: the interior of the secondary spherical particles is difficult to be coated, and interface side reaction is difficult to inhibit in the high-voltage charging and discharging process, so that the material structure is damaged; (4) easy flatulence: the secondary spherical particles easily cause problems such as ballooning. At present, most manufacturers adopt a continuous method to prepare the ternary precursor material with the conventional particle size (10-15 mu m), and the method has high yield and good batch stability. However, when the ternary precursor material with small particle size (3-5 μm) is prepared, the particle size distribution is difficult to control by adopting a continuous method, so that the particle size error is large.

The silicon-carbon cathode is used as a novel lithium ion battery cathode material and is more efficient than the current graphite cathode in the aspect of improving the energy density of the battery. Tesla has applied silicon-carbon negative electrodes to power batteries for vehicles, the application prospect of silicon-carbon negative electrode materials is more and more bright, and the silicon-carbon negative electrode materials are likely to become outstanding in negative electrode materials in the future.

The theoretical specific capacity of the graphite is 372mAh/g, and the theoretical specific capacity of the silicon negative electrode is up to 4200 mAh/g. Graphite is a well developed negative electrode material, and its energy density is almost fully developed, and it is a good way to combine with silicon in order to improve the energy density.

In the aspect of silicon-based negative electrodes, the research industry considers that the practical application effect of the silicon oxide-carbon composite material is better than that of a pure silicon-carbon composite material, particularly in the aspects of battery cyclability and stability, and the silicon oxide-carbon composite material is another research focus in the aspect of high-energy negative electrode materials in the industry.

Disclosure of Invention

In view of the above, the present invention provides a microchannel reactor, which mainly aims to prepare metal and metal compound particles with uniform and controllable particle size and morphology or metal and metal compound particles coated with other materials;

the invention provides a method for preparing precursor micro-nano particles of a lithium battery anode material, and mainly aims to prepare precursor micro-nano particles suitable for the lithium battery anode material, which are uniform and controllable in particle size and shape, continuous in process and suitable for large-scale production.

The invention provides a method for preparing precursor micro-nano particles of a negative electrode material, and mainly aims to prepare the precursor micro-nano particles suitable for the negative electrode material of a lithium battery, wherein the particle size and the shape are uniform and controllable, the process is continuous, and the method is suitable for large-scale production.

In order to achieve the purpose, the invention mainly provides the following technical scheme:

in one aspect, embodiments of the present invention provide a microchannel reactor, including: the device comprises an upper sealing plate, a first substrate, a second substrate and a lower sealing plate;

the upper sealing plate, the first substrate, the second substrate and the lower sealing plate are sequentially attached from top to bottom;

a feeding main groove I and a feeding branch groove I are formed in the lower side surface of the upper sealing plate;

a feeding main groove II and a feeding branch groove II are formed in the upper side surface of the substrate I;

the upper sealing plate and the first substrate are mutually sealed, attached and fixed; the first feeding main groove corresponds to the second feeding main groove to form a first feeding main channel; the feeding branch groove I and the feeding branch groove II correspond to each other to form a feeding branch channel I; one end of the feeding branch channel I is communicated with the feeding main channel I, and the other end of the feeding branch channel I is closed; the first feeding branch channel is multiple; a plurality of said feed branch channels are regularly distributed;

a feeding main groove III and a feeding branch groove III are formed in the lower side surface of the base plate II;

a through hole is formed between the feeding branch groove II and the feeding branch groove III; the through hole is communicated with the feeding branch groove II and the feeding branch groove III;

a feeding main groove IV and a feeding branch groove IV are formed in the upper side surface of the lower sealing plate;

the lower sealing plate and the substrate are mutually sealed, attached and fixed; the feeding main groove III and the feeding main groove IV correspond to each other to form a feeding main channel II; the feeding branch groove III and the feeding branch groove IV correspond to each other to form a feeding branch channel II; one end of the feeding branch channel II is communicated with the feeding main channel II, and the other end of the feeding branch channel II extends to the outer edge of the substrate II; the feeding branch channel II is multiple; the second feeding branch channel and the first feeding branch channel are distributed correspondingly.

Further, the first substrate and the second substrate are integrated plates;

the number of the plate pieces is multiple; a plurality of plates are overlapped, sealed and attached up and down;

the plates are bonded through high temperature.

Further, the through holes are multiple; the through holes are arranged at intervals along the direction of the first feeding branch channel;

the diameter of the through hole is gradually increased along the flow direction of the first feeding branch channel.

Further, the upper sealing plate is made of one of sapphire material, ceramic material and alloy material;

the first base plate, the second base plate, the lower sealing plate and the upper sealing plate are made of the same material.

In another aspect, embodiments of the present invention provide a method for preparing precursor micro-nanoparticles of a negative electrode material for a lithium battery,

(1) heating high-purity silicon tetrachloride or trichlorosilane to 1000 ℃;

(2) heating high-purity hydrogen to 1000 ℃;

(3) respectively conveying high-purity silicon tetrachloride and high-purity hydrogen or trichlorosilane and high-purity hydrogen to a feeding main channel I and a feeding main channel II of a micro-channel reactor; the microchannel reactor is at a constant temperature of 1380 ℃; the molar ratio of the silicon tetrachloride to the hydrogen is 1: 2-1: 2.5;

or conveying the trichlorosilane and the high-purity hydrogen to a feeding main channel I and a feeding main channel II of the microchannel reactor respectively; the microchannel reactor is at a constant temperature of 1100 ℃; the molar ratio of trichlorosilane to hydrogen is 1: 1-1: 1.2;

(4) reacting the gas at high temperature in a microchannel reactor to generate nano silicon and hydrogen chloride gas;

(5) the nano silicon and the hydrogen chloride gas are subjected to rapid cooling and gas-solid separation to obtain high-purity nano silicon particles.

In another aspect, embodiments of the present invention provide a method for preparing precursor micro-nano particles of a negative electrode material for a lithium battery,

(1) preparing a suspension of nano silicon and sodium silicate solution;

(2) preparing a precipitator; the precipitating agent is an aqueous solution of chloride, sulfate and nitrate, and the aqueous solution can enable a sodium silicate solution to generate a chemical precipitation reaction to generate a silicate precipitate; the precipitator is an acid solution which is generated by the chemical precipitation reaction of any one of hydrochloric acid, sulfuric acid, nitric acid, carbonic acid and oxalic acid and sodium silicate;

(3) respectively inputting the suspension and the precipitant into a first feeding main channel and a second feeding main channel of the microchannel reactor; the suspension and the precipitator are intersected in the microchannel reactor to carry out precipitation reaction, the precipitation reaction takes nano silicon as seed crystal, and silicate or silicon dioxide is precipitated on the surface of the nano silicon; the mol ratio of the sodium silicate to the precipitator is 1: 1;

(4) carrying out solid-liquid separation, cleaning and drying on reactants;

(5) slowly heating and calcining at 500-1200 ℃ to obtain the high-dispersion nano-silicon particles coated with metasilicate and monoxygen or the high-dispersion nano-silicon particles coated with silicon dioxide and monoxygen.

Further, the method for preparing the precursor micro-nano particles of the lithium battery cathode material adopts any one of the microchannel reactors to operate; the above method prepares nano silicon particles.

On the other hand, the embodiment of the invention provides a method for preparing precursor micro-nano particles of a lithium battery anode material, wherein the lithium battery anode material comprises a ternary anode material, a lithium-rich manganese-based anode material and a lithium iron phosphate anode material, and the preparation method comprises the following steps:

(1) preparing a mixed salt solution:

completely dissolving metal salt in water to prepare a salt solution with the metal ion concentration of 0.25-2mol/L to obtain a mixed salt solution; the metal salt is nickel salt, cobalt salt and aluminum salt, or nickel salt, cobalt salt, aluminum salt and lithium salt, or nickel salt, cobalt salt and manganese salt, or nickel salt, cobalt salt, manganese salt and lithium salt;

when the micro-nano positive electrode material of the lithium battery is a ternary positive electrode material, the molar ratio of metal ions in the nickel salt, the cobalt salt, the aluminum salt or the manganese salt is Ni: co: al or Mn ═ 5-9: 0.05-3: 0.05 to 3; or Ni, Co, Mn, 5-9: 0.05-3: 0.05 to 3; wherein Ni + Co + Al is 10 or Ni + Co + Mn is 10; the molar ratio of the lithium salt to the metal ions in the metal salts other than the lithium salt is Li: ni + Co + Al or Mn 1-1.2: 1;

when the lithium battery micro-nano positive electrode material is a lithium-rich manganese-based positive electrode material, the molar ratio of metal ions in the metal salt is Li: mn + Ni + Co ═ 3:2, Mn: ni + Co ═ 5-9: 1-5;

(2) preparing an alkali solution:

completely dissolving soluble alkali in water to prepare a solution with the solubility of the soluble alkali being 1-5mol/L, thus obtaining an alkali solution; the soluble alkali is one of ammonium bicarbonate, sodium hydroxide, 8-hydroxyquinoline, sodium carbonate, ammonia water and potassium hydroxide;

(3) injecting the mixed salt solution and the alkali solution into a first feeding main channel and a second feeding main channel of the microchannel reactor at the temperature of 10-80 ℃; the mixed salt solution and the alkali solution are converged in the microchannel reactor to generate a precipitation reaction, the precipitation reaction is carried out from the generation of the seed crystal to the growth of the crystal, when the crystal grows to a certain degree, the fluid of the mixed reaction timely flows out of the microchannel reactor, flows into the tubular reactor to be heated continuously to accelerate the reaction, and flows into an aging tank to be stirred and aged for 2-10 hours under normal pressure when the crystal grows to the design requirement, so as to obtain a coprecipitation reaction mixture;

(4) after solid-liquid separation is carried out on the precipitation reaction mixture, washing the solid matter for 3-4 times, and drying to obtain a precursor;

(5) the lithium battery micro-nano positive electrode material is a ternary positive electrode material, and when the mixed salt solution contains lithium salt, the precursor is subjected to high-temperature curing reaction to obtain the ternary positive electrode material, namely the lithium battery micro-nano positive electrode material;

when no lithium salt is included in the mixed salt solution: uniformly mixing the precursor with lithium salt, wherein the molar ratio of the precursor to metal elements in the lithium salt is 1:1-1.2, and carrying out high-temperature curing reaction to obtain a ternary cathode material, namely the micro-nano cathode material of the lithium battery;

when the lithium battery micro-nano positive electrode material is a lithium-rich manganese-based positive electrode material, uniformly mixing a precursor with a lithium salt, wherein the molar ratio of metal elements in the precursor except lithium elements to metal elements in the lithium salt is 1:1-1.2, and carrying out high-temperature curing reaction to obtain the lithium-rich manganese-based positive electrode material, namely the lithium battery micro-nano positive electrode material.

Further, in the step (1), the metal salt is a sulfate, a nitrate, an acetate, or a hydrochloride;

in the step (2), the soluble alkali is ammonium bicarbonate, sodium hydroxide, 8-hydroxyquinoline, sodium carbonate, ammonia water and potassium hydroxide; (ii) a

In the step (5), the lithium salt is at least one of lithium hydroxide, lithium acetate, lithium oxalate and lithium carbonate;

the molar ratio of metal ions in the nickel salt, the cobalt salt and the manganese salt is 5-8:2-1: 3-1;

the molar ratio of metal ions in the nickel salt, the cobalt salt and the aluminum salt is 5-8:3-1.5: 2-0.5.

Further, the method for preparing the precursor micro-nano particles of the lithium battery anode material adopts any one of the microchannel reactors to operate.

By the technical scheme, the microchannel reactor and the method for preparing the precursor micro-nano particles of the lithium battery anode material and the lithium battery cathode material have the advantages that:

the method can prepare precursor micro-nano particles suitable for the anode material and the cathode material of the lithium battery, has uniform and controllable particle size and shape, is continuous in process, and is suitable for large-scale production.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of a microchannel reactor according to an embodiment of the invention when a first substrate and a second substrate are attached to each other;

FIG. 2 is a schematic diagram of a microchannel reactor with a first substrate and a second substrate separated according to an embodiment of the invention;

FIG. 3 is a schematic diagram of a microchannel reactor according to an embodiment of the invention, when a first substrate and a second substrate are integrally disposed;

FIG. 4 is a schematic view of a microchannel reactor according to another embodiment of the present invention;

FIG. 5 is a schematic diagram of a microchannel reactor according to yet another embodiment of the invention;

FIG. 6 is a schematic view of an upper sealing plate of a microchannel reactor according to an embodiment of the present invention;

FIG. 7 is a schematic view of a first substrate in a microchannel reactor according to an embodiment of the invention; (ii) a

FIG. 8 is a schematic diagram of a second substrate in a microchannel reactor according to an embodiment of the invention;

FIG. 9 is a schematic view of a lower sealing plate of a microchannel reactor according to an embodiment of the present invention;

fig. 10 is a process flow chart of preparing nano silicon particles in a method for preparing precursor micro/nano particles of a lithium battery anode material according to an embodiment of the present invention;

fig. 11 is a process flow chart of preparing a high-dispersion nano-silicon particle coated with a metasilicate and silica oxide or a high-dispersion nano-silicon particle coated with a silica and silica oxide in a method for preparing a precursor micro-nano particle of a negative electrode material of a lithium battery according to an embodiment of the present invention;

FIG. 12 is a process flow diagram of the present invention for preparing a ternary cathode material and a lithium-rich manganese-based cathode material without the addition of a lithium salt in the preparation of a mixed salt solution;

FIG. 13 is a flow chart of a process for preparing a ternary cathode material by adding a lithium salt during the preparation of a mixed salt solution according to the present invention;

FIG. 14 is a microchannel reactor, aging tube reactor, and aging tank.

Shown in the figure:

1 is an upper sealing plate, 1-1 is a feeding main groove I, 1-2 is a feeding branch groove I, 2 is a base plate I, 2-1 is a feeding main groove II, 2-2 is a feeding branch groove II, 2-3 is a through hole, 3 is a base plate II, 3-1 is a feeding main groove III, 3-2 is a feeding branch groove III, 3-3 is a connecting hole, 4 is a lower sealing plate, 4-1 is a feeding main groove IV, and 4-2 is a feeding branch groove IV

Detailed Description

To further explain the technical means and effects of the present invention adopted to achieve the predetermined object, the following detailed description of the embodiments, structures, features and effects according to the present invention will be made with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "an embodiment" refers to not necessarily the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As shown in fig. 1 to 9, in one aspect, an embodiment of the present invention provides a microchannel reactor, including: the device comprises an upper sealing plate 1, a first substrate 2, a second substrate 3 and a lower sealing plate 4;

the upper sealing plate 1, the first substrate 2, the second substrate 3 and the lower sealing plate 4 are sequentially attached from top to bottom; a feeding main groove I1-1 and a feeding branch groove I1-2 are arranged on the lower side surface of the upper sealing plate 1; a feeding main groove II 2-2 and a feeding branch groove II 2-2 are arranged on the upper side surface of the substrate I2; the upper sealing plate 1 and the first substrate 2 are mutually sealed, attached and fixed; the feeding main groove I1-1 and the feeding main groove II 2-2 correspond to each other to form a feeding main channel I; the feeding branch groove I1-2 and the feeding branch groove II 2-2 correspond to each other to form a feeding branch channel I; one end of the feeding branch channel I is communicated with the feeding main channel I, and the other end of the feeding branch channel I is closed; the first feeding branch channel is multiple; a plurality of feeding branch channels are regularly distributed;

a feeding main groove III 3-1 and a feeding branch groove III 3-2 are formed in the lower side surface of the base plate II 3; a through hole 2-3 is arranged between the feeding branch groove II 2-2 and the feeding branch groove III 3-2; the through hole 2-3 is communicated with the feeding branch groove II 2-2 and the feeding branch groove III 3-2; the through hole 2-3 is punched in a laser punching mode; the upper side surface of the lower sealing plate 4 is provided with a feeding main groove IV 4-1 and a feeding branch groove IV 4-2; the feeding branch groove III 3-2 can penetrate through the thickness direction of the substrate II 3, and the through hole 2-3 is communicated with the feeding branch groove III 3-2; the third feeding support does not penetrate through the thickness direction of the second substrate 3, and a connecting hole 3-3 is additionally arranged on the second substrate 3, wherein the connecting hole 3-3 is arranged corresponding to the through hole 2-3; preferably, the connecting hole 3-3 is coaxially arranged with the through hole 2-3, having the same diameter.

The lower sealing plate 4 and the second substrate 3 are mutually sealed, attached and fixed; the feeding main groove III 3-1 and the feeding main groove IV 4-1 correspond to each other to form a feeding main channel II; the feeding branch groove III 3-2 and the feeding branch groove IV 4-2 correspond to each other to form a feeding branch channel II; one end of the feeding branch channel II is communicated with the feeding main channel II, and the other end of the feeding branch channel II extends to the outer edge of the substrate II 3; the feeding branch channels II are multiple; the second feeding branch channel and the first feeding branch channel are distributed correspondingly. The upper sealing plate 1 and the lower sealing plate 4 are preferably double-sided polishing plates; when a feeding main groove I1-1, a feeding main groove II 2-2, a feeding main groove III 3-1, a feeding main groove IV 4-1, a feeding branch groove I1-2, a feeding branch groove II 2-2, a feeding branch groove III 3-2 and a feeding branch groove IV 4-2 are machined, a groove with the width smaller than 2mm is etched by laser and assisted by wet etching, and a groove with the width larger than 2mm is machined by a diamond grinding head of a numerical control machine tool and assisted by wet etching.

The feeding branch groove two 2-2 of base plate one 2 degree of depth 100um-1000um, width depth ratio 1: 1-1.5: 1; the thickness of the first substrate 2 is preferably 2-5 times of the depth of the second feeding branch groove 2-2; preferably, the feeding branch groove II 2-2 is a groove with a semicircular section;

three 3-2 degree of depth 100um-1000um of feeding tributary slot of base plate two 3, width 100um-1000um, width depth ratio 1: 1-1.5: 1; the thickness of the second substrate 3 is preferably 2-5 times of the depth of the third feeding branch groove 3-2; preferably, the feeding branch groove III 3-2 is a groove with a semicircular section;

the upper sealing plate 1, the first substrate 2, the second substrate 3 and the lower sealing plate 4 are hermetically bonded, and the sealing bonding method is 1500-2000 ℃ high-temperature bonding. The edges of the upper sealing plate 1, the first substrate 2, the second substrate 3 and the lower sealing plate 4 are welded by covering and melting with laser or oxyhydrogen flame at about 2050 ℃ and are assisted by nano high-purity alumina as a solder, so that secondary pollution to reactants is avoided in high-temperature and strong acid-base environments.

The microchannel reactor provided by the embodiment of the invention has obvious advantages in material synthesis: the reaction fluid can be quickly mixed, the mixing time is shorter than the reaction time, a stable and uniform reaction environment is formed, back mixing is avoided, the particle size distribution of the obtained micro-nano particles is narrow, the materials are mixed according to the stoichiometric ratio of molecular or atomic linear degree, and products can be removed in time, so that agglomeration is reduced.

As a preference of the above embodiment, the first substrate 2 and the second substrate 3 are an integrated plate; namely, a feeding main groove II 2-2 and a feeding branch groove II 2-2 are processed on the upper side surface of the plate; a feeding main groove III 3-1 and a feeding branch groove III 3-2 are machined on the lower side surface of the plate; the upper side surface of the plate is attached to the upper sealing plate 1; the lower side surface of the plate is attached to the lower closing plate 4.

The number of the plate members is multiple; a plurality of plates are overlapped, sealed and attached up and down; so as to form a plurality of channels and simultaneously operate, thereby improving the operation efficiency. The plates are bonded at high temperature, so that the structure is reliable and sealing is realized.

Of course, the first substrate 2 and the second substrate 3 may be independently disposed, and the first substrate 2 and the second substrate 3 may be bonded at a high temperature.

As a preference of the above embodiment, the through-holes 2 to 3 are plural; the through holes 2-3 are arranged at intervals along the first feeding branch channel; in order to make the flow rate of the plurality of through holes 2-3 equal to the flow rate of the first branch passage, the area sum of the plurality of through holes 2-3 is the same as the cross-sectional area of the first branch passage. The number of the through holes 2-3 is preferably 2-20. The diameter of the through hole 2-3 is gradually increased along the flowing direction of the feeding branch channel I, so that the flow of each through hole 2-3 can be uniform, the fluid in the branch channel I is subjected to mixing reaction with the fluid in the branch channel II in a gradient manner, and the purposes of seed crystal generation, crystal growth and crystal forming are achieved.

The fluid in the branch channel I reacts with the fluid in the branch channel II through the through holes 2-3, the fluid is arranged at intervals in the plurality of channels and is melted into the branch channel II at intervals, so that the seed crystal can react with the fluid flowing in the through holes 2-3 when passing through the plurality of through holes 2-3, and the crystal can be gradually grown.

Preferably, the upper sealing plate 1 is made of one of sapphire, ceramic and alloy; the first base plate 2, the second base plate 3 and the lower sealing plate 4 are made of the same material as the upper sealing plate 1. The base plate I2, the base plate II 3, the lower sealing plate 4 and the upper sealing plate 1 are preferably made of sapphire materials; the sapphire material is high temperature resistant and corrosion resistant, does not need to be subjected to corrosion protection treatment, does not generate secondary pollution to products, and is very suitable for production to meet the requirements of high-purity materials such as lithium batteries, electronic materials, nano whisker materials, electromagnetism, advanced ceramics and the like. In the aspect of improving the material performance by coating the oxide or the carbon material on the lithium battery anode material precursor and the lithium battery cathode material nano-silicon, the microchannel reactor provided by the embodiment of the invention can realize accurate control under a microscopic condition, accurately control the thickness of the coating, enable the coating material to have high consistency and high dispersibility without agglomeration, and avoid grinding and grading the lithium battery coated precursor and the nano-silicon at the front end of a later lithium adding calcination stage, thereby avoiding damaging the coated precursor and the nano-silicon mechanism and influencing the performance of the lithium battery anode material and the silicon-carbon composite material.

The lithium battery has very high requirements on materials, the positive electrode material and the negative electrode material have very high requirements on the content of impurities influencing the performance of the battery, the impurity sources mainly have two ways, and raw materials are brought into and cause secondary pollution to production equipment. The micro-channel reactor provided by the embodiment of the invention is processed by a sapphire material resistant to strong acid and alkali, and can completely avoid pollution of production equipment in a strong acid and alkali environment, particularly pollution of magnetic impurities.

The technical process of the microchannel reactor provided by the embodiment of the invention has great technical and cost advantages in the preparation, doping and coating of precursors of single crystals, high-nickel and lithium-rich manganese-based anode materials and silicon-carbon composite cathode materials.

Further preferably, the upper sealing plate 1 and the lower sealing plate 4 have the same thickness; the thickness of the first substrate 2 is the same as that of the second substrate 3, so that the processing and the manufacturing are convenient; the thickness of the upper sealing plate 1 or the lower sealing plate 4 is 2-5 times that of the first substrate 2 or the second substrate 3, so that the overall strength and stability of the microchannel reactor are guaranteed.

On the other hand, the embodiment of the invention provides a method for preparing precursor micro-nano particles of a lithium battery anode material, and the process flow refers to fig. 10,

(1) heating high-purity silicon tetrachloride or trichlorosilane to 1000 ℃;

(2) heating high-purity hydrogen to 1000 ℃;

(4) reacting the gas at high temperature in a microchannel reactor to generate nano silicon and hydrogen chloride gas; and (3) selecting the pore diameters of the feeding branch channel I and the feeding branch channel II to obtain the nano silicon particles with different sizes.

The embodiment of the invention provides a method for preparing precursor micro-nano particles of a lithium battery cathode material, and the produced high-purity nano silicon particles are uniform in appearance, accurate in size control and free of secondary pollution, and are really nano-structure particles with nano characteristics.

As a preferred embodiment of the present invention, the method for preparing the precursor micro-nano particles of the negative electrode material of the lithium battery provided in the embodiment of the present invention uses the microchannel reactor to perform operations.

The embodiment of the invention provides a method for preparing precursor micro-nano particles of a lithium battery cathode material, wherein a microchannel reactor is controlled in a gradient manner from small to large through the number of through holes 2-3 and the aperture of the through holes 2-3, so that the formation of a crystal seed and the growth of a crystal are controlled; in order to avoid the blockage of the feeding branch channel I and the feeding branch channel II, the crystal grows to a certain size, the reactant flows out of the feeding branch channel II, the temperature is rapidly reduced, and gas-solid separation is carried out to obtain the high-purity nano silicon particles.

In another aspect, an embodiment of the present invention provides a method for preparing precursor micro-nano particles of a lithium battery anode material, and the process flow refers to fig. 11,

(1) preparing a suspension of nano silicon and sodium silicate solution; the preparation of the nano silicon can adopt the method.

(4) carrying out solid-liquid separation, cleaning and drying on reactants;

The embodiment of the invention provides a method for preparing precursor micro-nano particles of a lithium battery cathode material, wherein a microchannel reactor is controlled in a gradient manner from small to large through the number of through holes 2-3 and the aperture of the through holes 2-3, so that the formation of a crystal seed and the growth of a crystal are controlled; in order to avoid the blockage of the feeding branch channel I and the feeding branch channel II, the crystal grows to a certain size, the reactant flows out of the feeding branch channel II, and the reaction product is rapidly cooled and subjected to gas-solid separation to obtain the high-dispersion nano-silicon particles coated by the metasilicate and the silicon oxide or the high-dispersion nano-silicon particles coated by the silicon dioxide and the silicon oxide.

The method for preparing the precursor micro-nano particles of the lithium battery cathode material has the advantages of simple process and continuous process, prepares the cathode material precursor with high capacity, high multiplying power and high consistency, and has the advantages of good particle size and appearance consistency of the cathode material precursor, no agglomeration, high particle yield, good consistency of batch products and stable result repetition.

According to the method for preparing the precursor micro-nano particles of the lithium battery cathode material, micro-nano particles with different particle sizes can be produced by changing parameters such as the flow rate and the injection pressure of liquid flowing into each inlet of a microchannel reactor, the inner diameter and the length of a microchannel reaction channel and the like.

Example 1.

(1) Modifying the nano silicon, preparing slurry with a sodium silicate solution, and keeping a certain stirring speed to uniformly distribute the nano silicon in the sodium silicate solution to form a suspension of the nano silicon and the sodium silicate solution;

(2) preparing a precipitator; the precipitant consists of aqueous solutions of chloride, sulfate and nitrate of magnesium, or aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, carbonic acid and the like;

(4) carrying out solid-liquid separation, cleaning and drying on reactants;

(5) slowly heating and calcining at 500-1200 ℃ to obtain the high-dispersion nano-silicon particles coated with metasilicate and monoxygen or the high-dispersion nano-silicon particles coated with silicon dioxide and monoxygen. The coated nano silicon material is compounded with a carbon material to form the silicon-carbon composite lithium battery cathode material.

(1) preparing a mixed salt solution:

completely dissolving metal salt in water to prepare a salt solution with the metal ion concentration of 0.25-2mol/L to obtain a mixed salt solution; the metal salt is nickel salt, cobalt salt, aluminum salt, or nickel salt, cobalt salt, aluminum salt, lithium salt, or nickel salt, cobalt salt, manganese salt, lithium salt;

when the micro-nano positive electrode material of the lithium battery is a ternary positive electrode material, the molar ratio of metal ions in nickel salt, cobalt salt, aluminum salt or manganese salt is Ni: co: al or Mn ═ 5-9: 0.05-3: 0.05 to 3; or Ni, Co, Mn, 5-9: 0.05-3: 0.05 to 3; wherein Ni + Co + Al is 10 or Ni + Co + Mn is 10; the molar ratio of the lithium salt to the metal ions in the metal salt other than the lithium salt is Li: ni + Co + Al or Mn 1-1.2: 1;

(2) preparing an alkali solution:

According to the method for preparing the precursor micro-nano particles of the lithium battery anode material, provided by the invention, the pre-synthesis of seed crystals is not needed, the reaction condition is mild, a water phase system is adopted, the process is simple, the process is continuous, the anode material precursor with high capacity, high multiplying power and high consistency is prepared, the particle size and the appearance consistency of the anode material precursor are good, the material is mixed according to the molecular or atomic linear stoichiometric ratio, the agglomeration is avoided, the particle yield is high, the consistency of batch products is good, and the result is stable and repeatable.

According to the method for preparing the precursor micro-nano particles of the lithium battery anode material, micro-nano particles with different particle sizes can be produced by changing parameters such as the flow rate of liquid flowing into each inlet of a microchannel reactor, the injection pressure, the inner diameter and the length of a microchannel reaction channel.

According to the method for preparing the precursor micro-nano particles of the lithium battery anode material, the prepared anode material precursor can be classified into micro-particles and nano-silicon particles, the micro-particle size range is 0.1-500 um, and the nano-silicon particle size range is 10-1000 nm.

As a preference of the above embodiment, in the step (1), the metal salt is a sulfate, a nitrate, an acetate, or a hydrochloride;

As a preferred embodiment of the foregoing embodiment, the method for preparing the precursor micro-nano particles of the lithium battery positive electrode material provided in the embodiment of the present invention uses a microchannel reactor to perform operations.

In the preparation of the mixed salt solution, the metal salt is soluble metal salt, and the manganese salt can be one or the mixed salt of manganese sulfate, manganese nitrate, manganese chloride and manganese acetate; the nickel salt can be one or a mixture of nickel sulfate, nickel nitrate, nickel chloride and nickel acetate; the cobalt salt is one or a mixture of cobalt sulfate, cobalt nitrate and cobalt chloride.

When the lithium battery micro-nano positive electrode material is a ternary positive electrode material, lithium salt is added in two ways: firstly, adding lithium salt during preparation of a salt solution, and then directly carrying out high-temperature curing reaction after preparing a precursor; ② lithium salt is added after preparing precursor.

When the lithium battery micro-nano positive electrode material is a lithium-rich manganese-based positive electrode material, lithium salt is added when a salt solution is prepared, wherein the ratio of Li: the molar ratio of Mn + Ni + Co is 3:2, and Mn element accounts for 50-90% of (Mn + Ni + Co) element; after the precursor is prepared, lithium salt is added for high-temperature curing reaction.

FIG. 14 is a microchannel reactor, aging tube reactor, and aging tank of the present application. In the figure, A is a liquid inlet channel I, B is a liquid inlet channel II, C is a reaction channel, D is an aging tubular reactor, E is an aging tank, and F is a microchannel reactor unit.

With the above methods and the like understood, the method for preparing the lithium battery micro-nano positive electrode material of the present invention will be further described in detail with reference to the specific embodiment and fig. 12 and 14:

example 1.

The process flow is shown in fig. 12, and the specific operation steps are as follows:

(1) preparing a mixed salt solution:

nickel nitrate, cobalt nitrate, aluminum sulfate (Al2(SO4)3) were mixed as follows: mixing aluminum in a molar ratio of 8:1.5:0.05, completely dissolving the mixture in water, and preparing a mixed salt solution with the metal ion concentration of 0.25 mol/L;

(2) preparing an alkali solution:

completely dissolving ammonium bicarbonate in water to prepare 1mol/L aqueous alkali;

(3) respectively injecting the mixed salt solution and the alkali solution into a microchannel reactor for reaction at 25 ℃, continuously reacting through an aging tubular reactor, flowing into an aging tank, stirring and aging for 2 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

Because the lithium salt, the nickel salt, the cobalt salt and the like, as well as the precipitator, the complexing agent and the oxidant which are raw materials in the production of the lithium battery anode material are strong acid and strong alkali, the substrate of the microchannel reactor is corrosion-resistant sapphire, ceramics, alloy and glass, and is preferably sapphire. The substrate of this example is sapphire. The microchannel reactor comprises two close plates and 1-100 microchannel plates, wherein 2-1000 microchannels are arranged on the microchannel plates.

The microchannel reactor is a T-shaped microchannel reactor (as shown in figure 14), and comprises a liquid inlet channel I, a liquid inlet channel II and a reaction channel, wherein the outlet end of the reaction channel is communicated with the aging tubular reactor; the diameter of the liquid inlet channel is 1 mm; the inner diameter of the reaction channel is 1mm, and the length of the reaction channel is 10 mm; the length of the aging tube reactor was 50 mm. The invention selects the T-shaped microchannel reactor, limits the sizes of the liquid inlet channel, the reaction channel and the aging tubular reactor, can effectively avoid back mixing of reaction liquid, avoids pipeline blockage and simultaneously ensures complete reaction.

By adopting a microchannel reactor coprecipitation method to prepare the ternary cathode material precursor, the physical and chemical properties of the ternary cathode material precursor are improved, and the stacking density and the cycle performance of the nickel-cobalt-aluminum ternary cathode material can be improved.

(4) After solid-liquid separation is carried out on the precipitation reaction mixture, the solid matter is washed for 4 times by deionized water and then is placed in a drying oven to be dried for 24 hours in vacuum at the temperature of 80-200 ℃ to obtain a precursor of the ternary cathode material;

(5) uniformly mixing a ternary positive electrode material precursor with lithium hydroxide, wherein the molar ratio of Li (Ni + Co + Al) is 1.2:1, presintering for 5h at 500 ℃ in an oxygen atmosphere, and calcining for 24h at 900 ℃ to obtain a positive electrode material LiNi0.8Co0.15Al0.05O2, namely NCA811 for short, namely the lithium battery micron positive electrode material.

The product prepared in this example was in the form of microparticles with a 10um particle size yield of 91%.

The yield of 10um micron particles in the product prepared by the conventional preparation method is 32%, and the product needs to be further ground, crushed and sieved.

The preparation method of the lithium battery micron cathode material provided by the embodiment of the invention can be used for continuously preparing the lithium battery cathode material precursor micro-nano particles, is mild in condition, adopts a water phase system, is simple in process, is controllable in shape of the lithium battery cathode material precursor, is high in particle yield, is good in batch product consistency, is continuous in process, and is suitable for large-scale production.

Example 2.

The specific operation steps are as follows:

(1) preparing a mixed salt solution:

nickel sulfate (NiSO4), cobalt sulfate (CoSO4) and manganese sulfate (MnSO4) are mixed according to the molar ratio of Ni to Co to Mn of 8 to 1, and are completely dissolved in water to prepare a mixed salt solution with the metal ion concentration of 1 mol/L.

(2) Preparing an alkali solution:

sodium hydroxide was completely dissolved in water to prepare a 2mol/L aqueous alkali.

(3) Injecting the mixed salt solution and the alkali solution into a microchannel reactor for reaction at 50 ℃, then continuously reacting through an aging tubular reactor, flowing into an aging tank, stirring and aging for 3 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

The substrate of the microchannel reactor is made of corrosion-resistant ceramic and comprises two close plates and 5-20 microchannel plates, and 20-100 microchannels are arranged on the microchannel plates.

The microchannel reactor is a T-shaped microchannel reactor (as shown in fig. 14), and comprises a liquid inlet channel I, a liquid inlet channel II and a reaction channel, wherein the outlet end of the reaction channel is communicated with the aging tubular reactor. The diameter of a reaction channel in the microchannel reactor is the same as that of an inlet channel, and the diameter of a liquid inlet channel is 0.01-1 mm; the inner diameter of the reaction channel is 0.01-1.5mm, and the length is 10-200 mm; the length of the aging tubular reactor is 50-5000mm, and a proper micro-channel design is selected according to the particle size and the appearance of a required product. The invention selects the T-shaped microchannel reactor, limits the sizes of the liquid inlet channel, the reaction channel and the aging tubular reactor, can effectively avoid back mixing of reaction liquid, avoids pipeline blockage and simultaneously ensures complete reaction.

(4) And (3) carrying out solid-liquid separation on the precipitation reaction mixture, washing the solid matter with deionized water for 3 times, then placing the solid matter in a drying oven, and carrying out vacuum drying for 12 hours at the temperature of 200 ℃ to obtain a precursor of the ternary cathode material.

(5) Uniformly mixing a ternary positive electrode material precursor with lithium hydroxide (LiOH) according to the molar ratio of Li (Ni + Co + Mn) of 1.1:1, presintering the mixture for 20 hours at 300 ℃ in an oxygen atmosphere, and calcining the mixture for 40 hours at 700 ℃ to obtain an uncoated positive electrode material LiNi0.8Co0.1Mn0.1, namely NCM811 for short, namely the lithium battery micron positive electrode material.

The product prepared in this example was a microparticle with a yield of 92% microparticles of 5um size.

The yield of the micron particles with the particle size of 5um in the product prepared by the conventional preparation method is 31 percent, and the product needs to be further ground, crushed and sieved.

Example 3.

The specific operation steps are as follows:

(1) preparing a mixed salt solution:

nickel sulfate (NiSO4), cobalt sulfate (CoSO4) and manganese sulfate (MnSO4) are mixed according to the molar ratio of Ni to Co to Mn of 6 to 2, and are completely dissolved in water to prepare a mixed salt solution with the metal ion concentration of 2 mol/L.

(2) Preparing an alkali solution:

the potassium hydroxide is completely dissolved in water to prepare 5mol/L alkali solution.

(3) Injecting the mixed salt solution and the alkali solution into a microchannel reactor for reaction at the temperature of 80 ℃, then continuously reacting through an aging tubular reactor, flowing into an aging tank, stirring and aging for 10 hours at normal pressure, and obtaining a coprecipitation reaction mixture.

The substrate of the microchannel reactor is corrosion-resistant glass and comprises two close plates and 1-100 microchannel plates, wherein 2-1000 microchannels are arranged on the microchannel plates; preferably, the microchannel reactor comprises 5-20 microchannel plates, and 20-100 microchannels are arranged on the microchannel plates.

The microchannel reactor is a T-shaped microchannel reactor (as shown in fig. 14), and comprises a liquid inlet channel I, a liquid inlet channel II and a reaction channel, wherein the outlet end of the reaction channel is communicated with the aging tubular reactor. The diameter of a reaction channel in the microchannel reactor is the same as or different from that of an inlet channel, and the diameter of a liquid inlet channel is 0.01-1 mm; the inner diameter of the reaction channel is 0.01-1.5mm, and the length is 10-200 mm; the length of the aging tubular reactor is 50-5000 mm.

(4) And (3) carrying out solid-liquid separation on the precipitation reaction mixture, washing the solid matter with deionized water for 4 times, then placing the solid matter in a drying oven, and carrying out vacuum drying for 18h at the temperature of 150 ℃ to obtain a precursor of the ternary cathode material.

(5) Uniformly mixing a ternary positive electrode material precursor with lithium acetate, wherein the molar ratio of Li (Ni + Co + Mn) is 1.1:1, pre-sintering at 500 ℃ for 5h in an oxygen atmosphere, and then calcining at 900 ℃ for 24h to obtain an uncoated positive electrode material LiNi0.6Co0.2Mn0.2O2, namely NCM622, namely the lithium battery nano positive electrode material.

The product prepared in this example was nanoparticles, with a yield of 94% nanoparticles of 400nm size.

The yield of the nano particles with the particle size of 400nm in the product prepared by the conventional preparation method is 35%, and further grinding, crushing and screening are needed.

The preparation method of the lithium battery cathode material provided by the embodiment of the invention can be used for continuously preparing the lithium battery cathode material precursor micro-nano particles, is mild in condition, adopts a water phase system, is simple in process, is controllable in shape of the lithium battery cathode material precursor, is high in particle yield, is good in batch product consistency, is continuous in process, and is suitable for large-scale production.

Example 4 lithium iron phosphate cathode Material

The specific operation steps are as follows:

(1) preparing a mixed solution of ferric sulfate solution and phosphoric acid:

the battery-grade ferric sulfate is completely dissolved in water to prepare a mixed solution with the metal ion concentration of 2 mol/L. The molar ratio of the ferric phosphate to the phosphoric acid is 1: 2;

(2) preparation of a precipitation solution:

sodium hydroxide was completely dissolved in water to prepare a 3mol/L aqueous alkali.

(3) Injecting the mixed salt solution and the alkali solution into a microchannel reactor at 50 ℃ for reaction, then flowing into an aging tank, stirring and aging for 5 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

The substrate of the microchannel reactor of the embodiment is a sapphire substrate

(4) And (3) carrying out solid-liquid separation on the precipitation reaction mixture, washing the solid matter with deionized water for 4 times, then placing the solid matter in an oven, and carrying out vacuum drying for 12 hours at 120 ℃ to obtain precursor ferric phosphate of the nano lithium iron phosphate cathode material.

(5) And uniformly mixing the precursor of the nano lithium iron phosphate positive electrode material with lithium carbonate, wherein the molar ratio of Li to Fe is 1:1, pre-sintering at 600 ℃ for 2h, and then calcining at 900 ℃ for 2h to obtain the nano lithium iron phosphate positive electrode material, namely the nano positive electrode material of the lithium battery.

The product prepared in this example was nanoparticles, with a 50nm particle size microparticle yield of 90%.

The yield of 50nm micron particles in the product prepared by the conventional preparation method is 40%, and the product needs to be further ground, crushed and sieved.

The preparation method of the lithium battery nanometer positive electrode material can be used for continuously preparing the lithium battery lithium iron phosphate positive electrode material precursor iron phosphate nanoparticles, is mild in condition, adopts a water phase system, is simple in process, is controllable in shape of the lithium battery positive electrode material precursor, is high in particle yield, is good in batch product consistency, is continuous in process, and is suitable for large-scale production.

Example 5 alumina coated NCM811

The specific operation steps are as follows:

(1) preparing a sodium aluminate solution:

adding aluminum hydroxide into a sodium hydroxide solution at the temperature of 50-90 ℃, wherein the molar ratio of sodium hydroxide to aluminum hydroxide is 1:1, preparing a sodium aluminate solution with the concentration of 2 mol/L.

(2) Preparing a suspension solution:

adding the nano nickel-cobalt-manganese powder as the precursor of the anode material into a sodium aluminate solution, and stirring to form a homogeneous suspension.

(3) Preparation of the precipitation solution

The ammonium bicarbonate is completely dissolved in water to prepare 2mol/L alkali solution.

(4) And at the temperature of 60 ℃, filtering the mixed suspension solution, injecting the filtered mixed suspension solution and an alkali solution into a microchannel reactor for reaction, taking nickel-cobalt-manganese nano particles as seed crystals, precipitating a layer of aluminum hydroxide precipitate on the surface, flowing into an aging tank, stirring and aging for 8 hours under normal pressure, and obtaining the aluminum hydroxide coated nickel-cobalt-manganese precursor mixture.

The substrate of the microchannel reactor was corrosion resistant sapphire, and the rest was the same as the microchannel reactor of example 3.

(4) After solid-liquid separation of the precipitation reaction mixture, washing the solid substance with deionized water for 4 times, then placing the solid substance in an oven, and carrying out vacuum drying for 18h at 200 ℃ to obtain an alumina-coated nickel-cobalt-manganese ternary cathode material precursor;

(5) uniformly mixing the precursor of the nickel-cobalt-manganese ternary positive electrode material coated by the aluminum oxide with lithium carbonate, wherein the molar ratio of Li (Ni + Co + Mn) is 1.2:1, pre-sintering at 500 ℃ for 8h in an oxygen atmosphere, and calcining at 800 ℃ for 20h to obtain the nickel-cobalt-manganese nanometer positive electrode material coated by the aluminum oxide of the lithium battery.

The product prepared in this example was in the form of microparticles with a yield of 95% microparticles at 100 nm.

The yield of micron particles with the particle size of 100nm in the product prepared by the conventional preparation method is 36 percent, and the product needs to be further ground, crushed and sieved.

The preparation method of the lithium battery anode material coated with the aluminum oxide can continuously prepare the lithium battery anode material precursor aluminum oxide coated nano particles, has mild conditions, adopts a water phase system, has simple process, controllable shape of the lithium battery anode material coated precursor, high particle yield, good consistency of batch products, continuous process and suitability for large-scale production.

Example 6.

The process flow is shown in fig. 13, and the specific operation steps are as follows:

(1) preparing a mixed salt solution:

lithium acetate, nickel chloride, cobalt chloride and aluminum chloride are mixed according to the weight ratio of Li to Ni: co: 12 for Al: mixed in a molar ratio of 8.5:1.45:0.05, and completely dissolved in water to prepare a mixed salt solution with a metal ion concentration of 1 mol/L.

(2) Preparing an alkali solution:

sodium carbonate is completely dissolved in water to prepare 2mol/L alkali solution.

(3) Injecting the mixed salt solution and the alkali solution into a microchannel reactor for reaction at 50 ℃, then continuously reacting through an aging tubular reactor, flowing into an aging tank, stirring and aging for 8 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

(4) After solid-liquid separation is carried out on the precipitation reaction mixture, the solid matter is washed for 4 times by deionized water and then is placed in a drying oven to be dried for 18 hours in vacuum at the temperature of 110 ℃ to obtain a precursor of the ternary cathode material;

(5) and pre-sintering the precursor of the ternary cathode material in an oxygen atmosphere at 500 ℃ for 8h, and then calcining at 700 ℃ for 20h to obtain the ternary cathode material, namely the micron cathode material of the lithium battery.

The product prepared in this example was in the form of microparticles with a 3um particle size yield of 94%.

The yield of the micron particles with the particle size of 3um in the product prepared by the conventional preparation method is 38 percent, and the product needs to be further ground, crushed and sieved.

Example 7.

The process flow is shown in fig. 14, and the specific operation steps are as follows:

(1) preparing a mixed salt solution:

lithium acetate, cobalt acetate, nickel acetate and manganese acetate are mixed according to the weight ratio of Li: ni: co: mn was mixed at a molar ratio of 1.20:0.13:0.13:0.54, and completely dissolved in water to prepare a mixed salt solution having a metal ion concentration of 1 mol/L.

(2) Preparing an alkali solution:

(3) Injecting the mixed salt solution and the alkali solution into a microchannel reactor for reaction at 60 ℃, then continuing the reaction through an aging tubular reactor, flowing into an aging tank, stirring and aging for 7 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

(4) After solid-liquid separation of the precipitation reaction mixture, washing the solid matter with deionized water for 3 times, then placing the solid matter in a drying oven, and carrying out vacuum drying for 16 hours at the temperature of 140 ℃ to obtain a precursor;

(5) and (2) uniformly mixing the precursor with lithium carbonate, wherein the molar ratio of metal elements in the precursor except the lithium element to the metal elements in the lithium salt is 1:1.2, presintering the mixture in an oxygen atmosphere at 500 ℃ for 8 hours, and calcining the mixture at 800 ℃ for 20 hours to obtain the lithium-rich manganese-based positive electrode material, namely the lithium battery nano positive electrode material.

The product prepared in this example was nanoparticles, with a nanoparticle yield of 93% at 800 nm.

The yield of the nano particles with the particle size of 800nm in the product prepared by the conventional preparation method is 34 percent, and the product needs to be further ground, crushed and sieved.

Example 8.

(1) preparing a mixed salt solution:

lithium acetate, cobalt acetate, nickel acetate and manganese chloride are mixed according to the weight ratio of Li: ni: co: al 15: mixing the components in a molar ratio of 1:1:8, and completely dissolving the components in water to prepare a mixed salt solution with the metal ion concentration of 1 mol/L.

(2) Preparing an alkali solution:

(5) and (2) uniformly mixing the precursor with lithium carbonate, wherein the molar ratio of metal elements in the precursor except the lithium element to the metal elements in the lithium salt is 1:1, presintering the mixture in an oxygen atmosphere at 400 ℃ for 8 hours, and calcining the mixture at 800 ℃ for 20 hours to obtain the lithium-rich manganese-based positive electrode material, namely the lithium battery micron positive electrode material.

The product prepared in this example was a microparticle with a 4um particle size yield of 92%.

The yield of the micron particles with the particle size of 4um in the product prepared by the conventional preparation method is 32 percent, and the product needs to be further ground, crushed and sieved.

Example 9: nano titanium oxide

(1) Preparing titanyl sulfate solution, adding titanium oxide into dilute sulfuric acid solution to prepare titanyl sulfate solution with titanium ion concentration of 2 mol/L.

(2) Preparing a precipitator and preparing 4mol/L ammonia water solution.

(3) At normal temperature, titanyl sulfate solution and precipitator ammonia water solution are injected into a microchannel reactor for precipitation reaction, and the reaction speed is controlled to ensure that precipitate crystals form specific size and shape. The reaction mixture flowed out of the microchannel reactor into an aging tank for aging for 4 hours.

And (3) after solid-liquid separation of the precipitation reaction mixture, washing the solid matter with deionized water for 3 times, then placing the solid matter in a drying oven, and carrying out vacuum drying for 6 hours at the temperature of 140 ℃ to obtain the nano titanium oxide particles.

Example 10: preparation of nano ferrite

(1) Preparing a salt solution, namely mixing ferric sulfate, manganese sulfate, zinc sulfate or ferrite components combined by ferric sulfate, nickel sulfate, zinc sulfate and the like, and dissolving the mixture into deionized water according to a certain molar ratio to obtain a mixed solution with the concentration of metal ion liquid of 2 mol/L.

(2) Preparing a precipitation solution, dissolving a soluble alkali solution such as sodium hydroxide, ammonium bicarbonate and the like in deionized water, wherein the concentration of alkali ions is 2 mol/L.

(3) Injecting the mixed salt solution and the precipitation solution into a microchannel reactor for reaction at the temperature of between 10 and 80 ℃, continuously reacting through an aging tubular reactor, flowing into an aging tank, stirring and aging for 2 hours under normal pressure, and obtaining a coprecipitation reaction mixture.

(4) And (3) after solid-liquid separation is carried out on the precipitation reaction mixture, washing the solid matter for 3 times by using deionized water, then placing the solid matter in a drying oven, and carrying out vacuum drying for 16h at the temperature of 140 ℃ to obtain the micro-nano ferrite powder particles with high dispersion and high consistency.

Further still, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, with such terms being used only to distinguish one element from another. Without departing from the scope of the exemplary embodiments. Similarly, the terms first, second, etc. do not denote any order or order, but rather the terms first, second, etc. are used to distinguish one element from another. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.

Claims

A microchannel reactor, comprising: the device comprises an upper sealing plate, a first substrate, a second substrate and a lower sealing plate;

the upper sealing plate, the first substrate, the second substrate and the lower sealing plate are sequentially attached from top to bottom;

a feeding main groove I and a feeding branch groove I are formed in the lower side surface of the upper sealing plate;

a feeding main groove II and a feeding branch groove II are formed in the upper side surface of the substrate I;

the upper sealing plate and the first substrate are mutually sealed, attached and fixed; the first feeding main groove corresponds to the second feeding main groove to form a first feeding main channel; the feeding branch groove I and the feeding branch groove II correspond to each other to form a feeding branch channel I; one end of the feeding branch channel I is communicated with the feeding main channel I, and the other end of the feeding branch channel I is closed; the first feeding branch channel is multiple; a plurality of said feed branch channels are regularly distributed;

a feeding main groove III and a feeding branch groove III are formed in the lower side surface of the base plate II;

a through hole is formed between the feeding branch groove II and the feeding branch groove III; the through hole is communicated with the feeding branch groove II and the feeding branch groove III;

a feeding main groove IV and a feeding branch groove IV are formed in the upper side surface of the lower sealing plate;

the lower sealing plate and the substrate are mutually sealed, attached and fixed; the feeding main groove III and the feeding main groove IV correspond to each other to form a feeding main channel II; the feeding branch groove III and the feeding branch groove IV correspond to each other to form a feeding branch channel II; one end of the feeding branch channel II is communicated with the feeding main channel II, and the other end of the feeding branch channel II extends to the outer edge of the substrate II; the feeding branch channel II is multiple; the second feeding branch channel and the first feeding branch channel are distributed correspondingly.
The microchannel reactor of claim 1,

the first substrate and the second substrate are integrated plates;

the number of the plate pieces is multiple; a plurality of plates are overlapped, sealed and attached up and down;

the plates are bonded through high temperature.
The microchannel reactor of claim 1,

the number of the through holes is multiple; the through holes are arranged at intervals along the direction of the first feeding branch channel;

the diameter of the through hole is gradually increased along the flow direction of the first feeding branch channel.
The microchannel reactor of claim 1,

the upper sealing plate is made of one of sapphire material, ceramic material and alloy material;

the first base plate, the second base plate, the lower sealing plate and the upper sealing plate are made of the same material.
A method for preparing precursor micro-nano particles of a lithium battery cathode material is characterized in that,

(1) heating high-purity silicon tetrachloride or trichlorosilane to 1000 ℃;

(2) heating high-purity hydrogen to 1000 ℃;

(3) respectively conveying high-purity silicon tetrachloride and high-purity hydrogen or trichlorosilane and high-purity hydrogen to a feeding main channel I and a feeding main channel II of a micro-channel reactor; the microchannel reactor is at a constant temperature of 1380 ℃; the molar ratio of the silicon tetrachloride to the hydrogen is 1: 2-1: 2.5;

or conveying the trichlorosilane and the high-purity hydrogen to a feeding main channel I and a feeding main channel II of the microchannel reactor respectively; the microchannel reactor is at a constant temperature of 1100 ℃; the molar ratio of trichlorosilane to hydrogen is 1: 1-1: 1.2;

(4) reacting the gas at high temperature in a microchannel reactor to generate nano silicon and hydrogen chloride gas;

(5) and (3) rapidly cooling the nano silicon and the hydrogen chloride gas, and carrying out gas-solid separation to obtain nano silicon particles.
A method for preparing precursor micro-nano particles of a lithium battery cathode material is characterized in that,

(1) preparing a suspension of nano silicon and sodium silicate solution;

(2) preparing a precipitator; the precipitating agent is an aqueous solution of chloride, sulfate and nitrate, and the aqueous solution can enable a sodium silicate solution to generate a chemical precipitation reaction to generate a silicate precipitate; the precipitator is an acid solution which is generated by the chemical precipitation reaction of any one of hydrochloric acid, sulfuric acid, nitric acid, carbonic acid and oxalic acid and sodium silicate;

(3) respectively inputting the suspension and the precipitant into a first feeding main channel and a second feeding main channel of the microchannel reactor; the suspension and the precipitator are intersected in the microchannel reactor to carry out precipitation reaction, the precipitation reaction takes nano silicon as seed crystal, and silicate or silicon dioxide is precipitated on the surface of the nano silicon; the mol ratio of the sodium silicate to the precipitator is 1: 1;

(4) carrying out solid-liquid separation, cleaning and drying on reactants;

(5) slowly heating and calcining at 500-1200 ℃ to obtain the high-dispersion nano-silicon particles coated with metasilicate and monoxygen or the high-dispersion nano-silicon particles coated with silicon dioxide and monoxygen.
The method for preparing the precursor micro-nano particles for the negative electrode material of the lithium battery as claimed in claim 6,

operating with the microchannel reactor of any one of claims 1-4;

the method of claim 5 is used to produce nano-silicon particles.
A method for preparing precursor micro-nano particles of a lithium battery anode material is characterized in that the lithium battery anode material comprises a ternary anode material, a lithium-rich manganese-based anode material and a lithium iron phosphate anode material, and the preparation method comprises the following steps:

(1) preparing a mixed salt solution:

completely dissolving metal salt in water to prepare a salt solution with the metal ion concentration of 0.25-2mol/L to obtain a mixed salt solution; the metal salt is nickel salt, cobalt salt and aluminum salt, or nickel salt, cobalt salt, aluminum salt and lithium salt, or nickel salt, cobalt salt and manganese salt, or nickel salt, cobalt salt, manganese salt and lithium salt;

when the micro-nano positive electrode material of the lithium battery is a ternary positive electrode material, the molar ratio of metal ions in the nickel salt, the cobalt salt, the aluminum salt or the manganese salt is Ni: co: al or Mn ═ 5-9: 0.05-3: 0.05 to 3; or Ni, Co, Mn, 5-9: 0.05-3: 0.05 to 3; wherein Ni + Co + Al is 10 or Ni + Co + Mn is 10; the molar ratio of the lithium salt to the metal ions in the metal salts other than the lithium salt is Li: ni + Co + Al or Mn 1-1.2: 1;

when the lithium battery micro-nano positive electrode material is a lithium-rich manganese-based positive electrode material, the molar ratio of metal ions in the metal salt is Li: mn + Ni + Co ═ 3:2, Mn: ni + Co ═ 5-9: 1-5;

(2) preparing an alkali solution:

completely dissolving soluble alkali in water to prepare a solution with the solubility of the soluble alkali being 1-5mol/L, thus obtaining an alkali solution; the soluble alkali is one of ammonium bicarbonate, sodium hydroxide, 8-hydroxyquinoline, sodium carbonate, ammonia water and potassium hydroxide;

(3) injecting the mixed salt solution and the alkali solution into a first feeding main channel and a second feeding main channel of the microchannel reactor at the temperature of 10-80 ℃; the mixed salt solution and the alkali solution are converged in the microchannel reactor to generate a precipitation reaction, the precipitation reaction is carried out from the generation of the seed crystal to the growth of the crystal, when the crystal grows to a certain degree, the fluid of the mixed reaction timely flows out of the microchannel reactor, flows into the tubular reactor to be heated continuously to accelerate the reaction, and flows into an aging tank to be stirred and aged for 2-10 hours under normal pressure when the crystal grows to the design requirement, so as to obtain a coprecipitation reaction mixture;

(4) after solid-liquid separation is carried out on the precipitation reaction mixture, washing the solid matter for 3-4 times, and drying to obtain a precursor;

(5) the lithium battery micro-nano positive electrode material is a ternary positive electrode material, and when the mixed salt solution contains lithium salt, the precursor is subjected to high-temperature curing reaction to obtain the ternary positive electrode material, namely the lithium battery micro-nano positive electrode material;

when no lithium salt is included in the mixed salt solution: uniformly mixing the precursor with lithium salt, wherein the molar ratio of the precursor to metal elements in the lithium salt is 1:1-1.2, and carrying out high-temperature curing reaction to obtain a ternary cathode material, namely the micro-nano cathode material of the lithium battery;

when the lithium battery micro-nano positive electrode material is a lithium-rich manganese-based positive electrode material, uniformly mixing a precursor with a lithium salt, wherein the molar ratio of metal elements in the precursor except lithium elements to metal elements in the lithium salt is 1:1-1.2, and carrying out high-temperature curing reaction to obtain the lithium-rich manganese-based positive electrode material, namely the lithium battery micro-nano positive electrode material.
The method for preparing precursor micro-nano particles for a positive electrode material of a lithium battery according to claim 7,

in the step (1), the metal salt is sulfate, nitrate, acetate or hydrochloride;

in the step (2), the soluble alkali is ammonium bicarbonate, sodium hydroxide, 8-hydroxyquinoline, sodium carbonate, ammonia water and potassium hydroxide;

in the step (5), the lithium salt is at least one of lithium hydroxide, lithium acetate, lithium oxalate and lithium carbonate;

the molar ratio of metal ions in the nickel salt, the cobalt salt and the manganese salt is 5-8:2-1: 3-1;

the molar ratio of metal ions in the nickel salt, the cobalt salt and the aluminum salt is 5-8:3-1.5: 2-0.5.
The method for preparing precursor micro-nano particles of a lithium battery positive electrode material according to any one of claims 8 to 9, characterized in that the microchannel reactor according to any one of claims 1 to 4 is used for operation.