A morphology-controllable cobalt boride nanopowder and its preparation method

Abstract

This invention discloses a morphology-controllable cobalt boride nanoparticle and its preparation method, belonging to the field of nanomaterial preparation technology. The powder is amorphous cobalt boride nanoparticles that can exhibit nanospherical or flower-like structures. The specific preparation steps include: first, dissolving a reducing agent in deionized water and purging with an inert gas to remove dissolved oxygen, while simultaneously purging a soluble cobalt salt solution with an inert gas for protection; both solutions are stored at low temperature. Second, reacting the soluble cobalt salt solution and the reducing agent solution in different ways, and depending on the feeding method, cobalt boride nanoparticles with different morphologies can be obtained, achieving morphology controllability. The preparation conditions of this invention are mild, the product purity is high, the controllability is strong, the preparation process is simple, and the manufacturing cost is low, enabling the mass production of cobalt boride materials.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation technology, and more specifically, to a morphology-controllable nano-cobalt boride powder and its preparation method. Background Technology

[0002] The rapid development of the new energy vehicle market has placed increasingly higher demands on the energy density and cycle life of lithium-ion batteries. Due to their crucial role in improving the energy density and cycle life of lithium-ion batteries, ternary cathode materials have attracted significant market attention.

[0003] In high-nickel ternary materials, the thermal decomposition temperature decreases and thermal stability deteriorates with increasing nickel content. During charge and discharge, partial transformation to spinel-type and NiO-type rock salt phases and the formation of pores lead to irreversible structural damage. Furthermore, the reaction between the electrode and the electrolyte generates gas, causing heat dissipation and a series of safety issues.

[0004] By coating the cathode material with specific materials, the structural stability of the material can be significantly improved, and the reactivity between the material surface and the electrolyte can be reduced. Cobalt boride (CoB), as a metallic compound, contains no oxygen and can form stable and effective bonds with the surface of the cathode material, thus significantly improving the cycle stability of the cathode material.

[0005] As a coating agent, cobalt boride is required to have the smallest possible particle size and the narrowest possible particle size distribution to achieve full coating of the cathode material. Currently, the main methods for preparing cobalt boride include ball milling, vapor deposition, thermal decomposition, and electrodeposition. These methods suffer from high energy consumption, poor controllability, environmental pollution, and are not conducive to large-scale production. Furthermore, the materials produced have large particle sizes, wide particle size distributions, poor controllability, and high costs, which severely limit the widespread application of cobalt boride. Therefore, exploring novel synthesis methods to achieve controllable preparation of cobalt boride under mild conditions and with simple equipment is of great significance for advancing the practical application of cobalt boride materials. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing morphology-controllable nano-cobalt boride powder, so as to solve the problems of high energy consumption, poor controllability, easy environmental pollution, unfavorable to large-scale production, large particle size, wide particle size distribution, poor controllability and high cost of the existing preparation methods.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing morphology-controllable cobalt boride nanoparticles, comprising the following steps:

[0008] S1: Weigh the reducing agent and add it to the solvent while stirring. During the stirring process, continuously introduce inert gas into the solution to obtain solution A and store it. The reducing agent includes one of lithium borohydride, sodium borohydride, and potassium borohydride.

[0009] Weigh out a soluble cobalt salt aqueous solution, dilute it, add a complexing agent and stir. Adjust the pH of the solution to 5-6, and continuously purge the solution with inert gas to obtain solution B and store it.

[0010] S2: Add the A liquid and B liquid prepared in step S1 into the reaction vessel, start the stirring and cooling cycle, so that the A liquid and B liquid begin to react, and during the reaction process, the temperature of the reaction system is maintained below 5°C;

[0011] S3: After the reaction in step S2 is completed, continue stirring until no more bubbles are generated in the slurry. Then, perform solid-liquid separation on the slurry after the reaction. After the filter cake is processed, the morphology-controllable nano-cobalt boride powder material is obtained.

[0012] In one possible implementation, in step S1, the inert gas is one or both of argon and nitrogen, and the storage temperature for obtaining and storing liquid A and obtaining and storing liquid B is below 5°C.

[0013] In one possible implementation, in step S1, the reducing agent is sodium borohydride, the solution A is an aqueous solution of sodium borohydride, and the concentration of the aqueous solution of sodium borohydride is 0.5-3M.

[0014] In one possible implementation, in step S1, the soluble cobalt salt aqueous solution is one of cobalt chloride solution, cobalt nitrate solution, cobalt sulfate solution, and cobalt acetate solution, and the concentration of the soluble cobalt salt aqueous solution is 0.5-1.5M.

[0015] In one possible implementation, in step S1, the complexing agent is citric acid, sodium citrate, or ammonium citrate; the molar ratio of the soluble cobalt salt to the reducing agent is 1:(2-3); and the molar ratio of the complexing agent to the soluble cobalt salt is (0-1):4.

[0016] In one possible implementation, in step S2, liquid A and liquid B are added in the following manner:

[0017] S21: First, pour the B solution into the reaction vessel, then add the A solution to the reaction vessel by titration to react with the B solution; or:

[0018] S22: Liquid A and liquid B are simultaneously added to the reaction vessel by titration, so that both participate in the reaction;

[0019] The titration speed is 160-240 mL / min, and the stirring speed is 300-600 rpm.

[0020] In one possible implementation, when liquid A and liquid B are added in step S2 in the manner of S21, the nano-cobalt boride powder material in step S3 is spherical nano-cobalt boride powder; when liquid A and liquid B are added in the manner of S22, the nano-cobalt boride powder material in step S3 is flower-shaped nano-cobalt boride powder.

[0021] In one possible implementation, in step S3, the continuous stirring time is 1-2 hours, the stirring speed is 100-300 rpm, and the reaction temperature is kept below 5°C in step S3.

[0022] In one possible implementation, in step S3, the solid-liquid separation process is positive pressure filtration or negative pressure filtration; the filter cake treatment includes filtering, washing, and drying the filter cake, wherein the filtration is performed by separating the solid and liquid under positive or negative pressure to obtain the filter cake; the washing is performed by washing the filter cake multiple times with deionized water and anhydrous ethanol, wherein the water washing is performed 3-6 times and the ethanol washing is performed 1-3 times, and the water washing temperature is 40-80°C; the drying includes drying under inert gas protection or vacuum drying, the drying temperature is 60-100°C, and the drying time is 8-24 hours.

[0023] Compared with the prior art, the method for preparing morphology-controllable nano-cobalt boride powder disclosed in this application has the following advantages: This invention provides a method for preparing morphology-controllable nano-cobalt boride. This invention adopts a liquid chemical reduction method, and by controlling the addition of metal salt solution and reducing agent solution, cobalt boride powder with different morphologies can be selectively synthesized, and all of them are nanoscale primary crystal particles, thereby realizing the morphology-controllable preparation of cobalt boride nanomaterials.

[0024] In the preparation method of this invention, when solutions A and B are titrated simultaneously, and without a complexing agent, the growth of crystal nuclei tends to be isotropic, preferentially growing along a two-dimensional plane. As the nucleation concentration increases, the nanosheets self-assemble into a three-dimensional structure. When solution A is added to solution B, due to the complexation of cobalt ions, their reduction undergoes a "slow-release" process, resulting in a decrease in the nucleation concentration. The growth of crystal nuclei tends to be anisotropic, preferentially combining into granular morphology, ultimately growing into spherical particles. The methods reported in the prior art typically suffer from uncontrollable reactions due to the strong reducing properties of borohydrides and their intense reduction with metals. This results in most synthesized products exhibiting drawbacks such as large and uncontrollable particle size, severe particle agglomeration, wide particle size distribution, and small specific surface area. This invention, by controlling different feeding methods—either adding solution A to solution B or titrating solutions A and B simultaneously—not only can the morphology of the product be controlled, but the resulting product also possesses advantages such as small particles, minimal agglomeration, and narrow particle size distribution. When solution A is added dropwise to solution B, the reduction degree is controllable through the "slow release" of cobalt ions. When solutions A and B are added simultaneously, the reduction degree can also be controlled by maintaining the concentration of nucleating ions at a low level throughout the reaction system. In summary, the method of this invention effectively solves the problems of high energy consumption, poor controllability, environmental pollution, and difficulty in large-scale production in current cobalt boride preparation processes. This invention provides a method for preparing morphology-controllable nano-cobalt boride, which uses low-cost raw materials, has a simple process, and is pollution-free, offering significant guidance for the application of cobalt boride materials in various fields.

[0025] Another technical problem to be solved by the present invention is to provide a morphology-controllable nano-cobalt boride powder, so as to solve the problems of large particle size, wide particle size distribution and poor controllability of existing nano-cobalt boride powder materials.

[0026] To address the aforementioned technical problems, this invention provides a morphology-controllable cobalt boride nanopowder, which is prepared using the method described above. Attached Figure Description

[0027] Figure 1 The X-ray diffraction pattern of the spherical cobalt boride nanoparticles prepared in Example 1 is shown below.

[0028] Figure 2 The X-ray diffraction pattern of the flower-shaped cobalt boride nanoparticles prepared in Example 2 is shown below.

[0029] Figure 3 This is a low-magnification scanning electron microscope image of the spherical cobalt boride nanoparticles prepared in Example 3;

[0030] Figure 4 This is a high-magnification scanning electron microscope image of the spherical cobalt boride nanoparticles prepared in Example 3;

[0031] Figure 5 This is a low-magnification scanning electron microscope image of the flower-shaped cobalt boride nanoparticles prepared in Example 4;

[0032] Figure 6 This is a high-magnification scanning electron microscope image of the flower-shaped cobalt boride nanoparticles prepared in Example 4;

[0033] Figure 7 XPS spectra of the spherical cobalt boride nanoparticles prepared in Example 5: (a) is the full spectrum, (b) is B1s, and (c) is Co 2P3 / 2. Detailed Implementation

[0034] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0035] This invention provides a morphology-controllable nano-cobalt boride powder and its preparation method, specifically including the following scheme:

[0036] In a first aspect, the present invention provides a method for preparing morphology-controllable cobalt boride nanoparticles, the method comprising the following steps:

[0037] S1. First, weigh a certain amount of reducing agent, add a certain amount of water, stir to dissolve and prepare an aqueous solution of reducing agent, and continuously pass inert gas to remove dissolved oxygen in the solution. Then, store the reducing agent solution at low temperature. This solution is designated as solution A.

[0038] Weigh a certain amount of soluble cobalt salt aqueous solution, dilute it with a certain amount of water, add a certain amount of complexing agent and stir to dissolve it. Then add alkali solution to adjust the pH to 5-6, and continuously pass inert gas to remove dissolved oxygen in the solution. After that, store the aqueous solution of cobalt salt complex at low temperature. This solution is numbered as solution B.

[0039] S2. Add liquid A and liquid B into the reactor in a certain way, start the stirring and cooling cycle, and let liquid A and liquid B start to react. The overall reaction temperature is maintained at a low temperature throughout the reaction process by cooling.

[0040] S3. After the reaction of liquid A and liquid B is complete, continue the reaction for a certain period of time, keeping the system at a low temperature until no more bubbles are generated in the slurry. Then, separate the solid and liquid components of the slurry after the reaction, and obtain nano-cobalt boride powder materials with different morphologies after processing the filter cake.

[0041] Further, the reducing agent in step S1 refers to lithium borohydride, sodium borohydride, or potassium borohydride, preferably sodium borohydride; the concentration of the sodium borohydride aqueous solution is 0.5-3M; the inert gas refers to argon, nitrogen, or a mixture of argon and nitrogen, preferably nitrogen; and the low-temperature storage refers to storing solution A in an environment below 5°C.

[0042] Further, in step S1, the soluble cobalt salt aqueous solution refers to a cobalt chloride solution, cobalt nitrate solution, cobalt sulfate solution, or cobalt acetate solution, preferably a cobalt chloride solution; the concentration of the cobalt salt is 0.5-1.5M; the molar ratio of the cobalt salt to the reducing agent sodium borohydride is 1:2-1:3; the complexing agent refers to citric acid, sodium citrate, or ammonium citrate, preferably sodium citrate; the amount of sodium citrate added is 0-1 / 4 of the molar amount of cobalt; the inert gas refers to argon, nitrogen, or a mixture of argon and nitrogen, preferably nitrogen; and the low-temperature storage refers to storing solution B in an environment below 5°C.

[0043] Further, in step S2, adding liquid A and liquid B to the reaction vessel in a certain manner means that liquid B can be poured into the reaction vessel first, and then liquid A can be added to the reaction vessel by titration to react with liquid B, or liquid A and liquid B can be added to the reaction vessel simultaneously by titration so that both participate in the reaction; the dropping rate is 160-240 mL / min, preferably 180-200 mL / min; the stirring speed is 300-600 rpm; the reaction is carried out at low temperature throughout the process means that the temperature of the reaction system is maintained below 5°C by cooling; the cooling method can be to cool the reaction vessel by circulating a coolant.

[0044] Furthermore, in step S2 above, by adding liquid B dropwise from liquid A, spherical cobalt boride nanoparticles can be obtained in step S3; by adding liquid A and liquid B dropwise simultaneously, flower-shaped cobalt boride nanoparticles can be obtained in step S3.

[0045] Further, in step S3, continuing the reaction for a certain period of time after the reaction of liquid A and liquid B is complete refers to continuing the stirring reaction for 1-2 hours; maintaining the system at a low temperature during this period means keeping the reaction system below 5°C; the cooling method can be to cool the reaction vessel by circulating a coolant; the stirring speed is 100-300 rpm; the solid-liquid separation method of the slurry can be positive pressure filtration or negative pressure filtration, preferably positive pressure filtration; the filter cake treatment method includes filtration, washing, and drying processes; the filtration... This refers to separating solids and liquids using positive or negative pressure to obtain a filter cake; the washing refers to washing several times with deionized water and anhydrous ethanol, wherein the water washing is performed 3-6 times and the ethanol washing is performed 1-3 times, preferably 4 times with water and 1 time with ethanol, and the water washing temperature is 40-80℃, preferably 60-80℃; the drying refers to drying under inert gas protection or vacuum drying, preferably vacuum drying; the drying temperature is 60-100℃, preferably 80-100℃; the drying time is 8-24h, preferably 12-24h.

[0046] Secondly, the present invention provides nano-cobalt boride powder with controllable morphology prepared by the above method.

[0047] The technical solution of the present invention will be explained in detail below with reference to specific experimental conditions, including specific weight, time, temperature, pH value, etc.:

[0048] Example 1

[0049] A morphology-controllable cobalt boride nanopowder and its preparation method, comprising the following steps:

[0050] S1. First, weigh 1891.5g of sodium borohydride, add 20kg of deionized water, stir to dissolve and prepare an aqueous solution of sodium borohydride, and continuously purge nitrogen gas to remove dissolved oxygen in the solution. Then, store the sodium borohydride solution at 0℃. This solution is designated as solution A.

[0051] Weigh 9881g of a cobalt chloride solution with a cobalt content of 11.928%, then dilute it with 12.31kg of deionized water, add 645g of anhydrous sodium citrate and stir to dissolve, then add 20% ammonia water to adjust the pH to 6, and continuously purge nitrogen gas to remove dissolved oxygen from the solution. Then store the solution at 0℃ and label it solution B.

[0052] S2. After injecting solution B into the 50L reactor, pre-cool it to 0℃ and start stirring at 450rpm. Then, drop solution A into the reactor at a flow rate of 200mL / min to start the reaction between solution A and solution B. The overall reaction temperature is maintained below 5℃ throughout the reaction process by cooling.

[0053] S3. After the addition of solution A is complete, continue the reaction for 1 hour, keeping the system below 5°C until no more bubbles are generated in the slurry. Then, filter the slurry after the reaction. Wash the filter cake 4 times with water at 60°C and once with anhydrous ethanol before vacuum drying at 80°C for 20 hours.

[0054] Figure 1 The image shows the XRD pattern of the spherical cobalt boride nanoparticles prepared in Example 1. As can be seen from the image, the material has the typical XRD pattern of an amorphous substance. There are no obvious characteristic peaks in the XRD pattern, and only a broadened diffraction peak appears near 2θ = 45°, indicating that the prepared cobalt boride is an amorphous substance.

[0055] Example 2

[0056] A morphology-controllable cobalt boride nanopowder and its preparation method, comprising the following steps:

[0057] S1. First, weigh 1891.5g of sodium borohydride, add 20kg of deionized water, stir to dissolve and prepare an aqueous solution of sodium borohydride, and continuously purge nitrogen gas to remove dissolved oxygen in the solution. Then, store the sodium borohydride solution at 0℃. This solution is designated as solution A.

[0058] Weigh 9881g of a cobalt chloride solution with a cobalt content of 11.928%, then dilute it with 12.31kg of deionized water, then add 20% ammonia water to adjust the pH to 6, and continuously purge nitrogen gas to remove dissolved oxygen from the solution. After that, store the solution at 0℃. This solution is designated as solution B.

[0059] S2. Add solution A and solution B dropwise into a 50L reactor simultaneously to participate in the reaction. The drop rate of solution A is 200mL / min and the drop rate of solution B is 180mL / min. The stirring speed is 450rpm. The overall reaction temperature is maintained below 5℃ throughout the reaction process by cooling.

[0060] S3. After both solutions A and B have been added, continue the reaction for 1 hour, keeping the system below 5°C until no more bubbles are generated in the slurry. Then, filter the slurry after the reaction. Wash the filter cake 4 times with water at 60°C and once with anhydrous ethanol before vacuum drying at 80°C for 20 hours.

[0061] Figure 2 The image shows the XRD pattern of the spherical cobalt boride nanoparticles prepared in Example 2. As can be seen from the image, the material has the typical XRD pattern of an amorphous substance. There are no obvious characteristic peaks in the XRD pattern, and only a broadened diffraction peak appears near 2θ = 45°, indicating that the prepared cobalt boride is an amorphous substance.

[0062] Example 3:

[0063] A morphology-controllable cobalt boride nanopowder and its preparation method, comprising the following steps:

[0064] S1. First, weigh 1664.5g of sodium borohydride, add 20kg of deionized water, stir to dissolve and prepare an aqueous solution of sodium borohydride, and continuously purge nitrogen gas to remove dissolved oxygen in the solution. Then, store the sodium borohydride solution at 0℃. This solution is designated as solution A.

[0065] Weigh 9881g of a cobalt chloride solution with a cobalt content of 11.928%, then dilute it with 12.31kg of deionized water, add 645g of anhydrous sodium citrate and stir to dissolve, then add 20% ammonia water to adjust the pH to 6, and continuously purge nitrogen gas to remove dissolved oxygen from the solution. Then store the solution at 0℃ and label it solution B.

[0066] S2. After injecting solution B into the 50L reactor, pre-cool it to 0℃ and start stirring at 600rpm. Then, drop solution A into the reactor at a flow rate of 180mL / min to start the reaction between solution A and solution B. The overall reaction temperature is maintained below 5℃ throughout the reaction process by cooling.

[0067] S3. After the addition of solution A is complete, continue the reaction for 1 hour, keeping the system below 5°C until no more bubbles are generated in the slurry. Then, filter the slurry after the reaction. Wash the filter cake 4 times with water at 60°C and once with anhydrous ethanol before vacuum drying at 100°C for 12 hours.

[0068] Figure 3 The image shows a low-magnification scanning electron microscope image of cobalt boride prepared in Example 3. As can be seen from the image, the obtained cobalt boride is a uniformly dispersed spherical nanoparticle with small and uniformly distributed particles, a narrow particle size distribution, and no obvious agglomeration. Figure 4 The image shows a high-magnification scanning electron microscope image of the spherical cobalt boride nanoparticles prepared in Example 3. As can be seen from the image, the original crystals of the prepared cobalt boride powder are around 50 nm.

[0069] Example 4

[0070] A morphology-controllable cobalt boride nanopowder and its preparation method, comprising the following steps:

[0071] S1. First, weigh 1664.5g of sodium borohydride, add 20kg of deionized water, stir to dissolve and prepare an aqueous solution of sodium borohydride, and continuously purge nitrogen gas to remove dissolved oxygen in the solution. Then, store the sodium borohydride solution at 0℃. This solution is designated as solution A.

[0072] Weigh 9881g of a cobalt chloride solution with a cobalt content of 11.928%, then dilute it with 12.31kg of deionized water, then add 20% ammonia water to adjust the pH to 6, and continuously purge nitrogen gas to remove dissolved oxygen from the solution. After that, store the solution at 0℃. This solution is designated as solution B.

[0073] S2. Add solution A and solution B dropwise into a 50L reactor simultaneously to participate in the reaction. The drop rate of solution A is 200mL / min and the drop rate of solution B is 180mL / min. The stirring speed is 450rpm. The overall reaction temperature is maintained below 5℃ throughout the reaction process by cooling.

[0074] S3. After both solutions A and B have been added, continue the reaction for 1 hour, keeping the system below 5°C until no more bubbles are generated in the slurry. Then, filter the slurry after the reaction. Wash the filter cake 4 times with water at 60°C and once with anhydrous ethanol before vacuum drying at 80°C for 20 hours.

[0075] Figure 5 The image shows a low-magnification scanning electron microscope image of the flower-shaped cobalt boride prepared in Example 4. As can be seen from the image, the obtained cobalt boride is a uniformly dispersed flower-shaped nanoparticle with fine and uniformly distributed particles, a narrow particle size distribution, and no obvious agglomeration. Figure 6 The image shows a high-magnification scanning electron microscope image of the flower-shaped cobalt boride nanoparticles prepared in Example 4. As can be seen from the image, the original crystals of the prepared flower-shaped cobalt boride powder are around 100 nm.

[0076] Example 5:

[0077] A spherical nano-cobalt boride powder and its preparation method, comprising the following steps:

[0078] S1. First, weigh 1891.5g of sodium borohydride, add 22.5kg of deionized water, stir to dissolve and prepare an aqueous solution of sodium borohydride, and continuously purge nitrogen gas to remove dissolved oxygen in the solution. Then, store the sodium borohydride solution at 0℃. This solution is designated as solution A.

[0079] Weigh 9881g of cobalt chloride solution with a cobalt content of 11.928%, then dilute it with 9.31kg of deionized water, add 950g of anhydrous sodium citrate and stir to dissolve, then add 20% ammonia water to adjust the pH to 6, and continuously purge nitrogen to remove dissolved oxygen from the solution. Then store the solution at 0℃ and label it solution B.

[0080] S2. After injecting solution B into the 50L reactor, pre-cool it to 0℃ and start stirring at 450rpm. Then, drop solution A into the reactor at a flow rate of 180mL / min to start the reaction between solution A and solution B. The overall reaction temperature is maintained below 5℃ throughout the reaction process by cooling.

[0081] S3. After the addition of solution A is complete, continue the reaction for 1 hour, keeping the system below 5°C until no more bubbles are generated in the slurry. Then, filter the slurry after the reaction. Wash the filter cake 4 times with water at 60°C and once with anhydrous ethanol before vacuum drying at 100°C for 14 hours.

[0082] Figure 7 The XPS spectra of the spherical cobalt boride nanoparticles prepared in Example 5 are shown in Figure (a). The surface elemental valence state characterization diagram shows the presence of cobalt, boron, carbon, and oxygen on the surface. The high presence of carbon and oxygen is due to the introduction of foreign carbon for charge correction during the testing process and the inevitable oxidation of the material surface. Figure (b) shows the XPS spectrum of B1s. The peak at 187.8 eV can be attributed to the interaction between boron and cobalt, while the peak at 191.8 eV corresponds to boron-oxygen compounds, which is due to surface oxidation of CoB during synthesis or exposure to the atmosphere. Figure (c) shows the XPS spectrum of Co 2p. The peak at 778.2 eV corresponds to Co in CoB. 0 The additional peak at 781.3 eV indicates that Co is generated due to spontaneous oxidation of the surface. 2+ The substance. Notably, compared to pure boron, boron has a positive chemical shift of 0.6 eV, indicating that element boron does not exist in a free state but is bonded to the metal Co. Some of the electrons of boron are transferred to Co through hybridization of the 2p state of boron with the d orbitals of the metal, occupying the d orbitals of Co. This makes boron electron-deficient and the metal electron-rich, which enhances its electrochemical performance.

[0083] The above-described embodiments and experiments further demonstrate that the present invention provides a method for preparing morphology-controllable nano-cobalt boride powder with mild preparation conditions, high product purity, strong controllability, simple preparation process, low manufacturing cost, and the ability to achieve mass production of cobalt boride materials. Moreover, the morphology of the prepared nano-cobalt boride powder is controllable, which has high commercial value and promotion value.

[0084] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a morphology-controllable cobalt boride nanopowder, characterized in that, Includes the following steps: S1: Weigh the reducing agent and add it to the solvent while stirring. During the stirring process, continuously introduce inert gas into the solution to obtain solution A and store it. The reducing agent includes one of lithium borohydride, sodium borohydride, and potassium borohydride. Weigh out a soluble cobalt salt aqueous solution, dilute it, add a complexing agent and stir. Adjust the pH of the solution to 5-6, and continuously purge the solution with inert gas to obtain solution B and store it. The storage temperature for obtaining and storing liquid A and obtaining and storing liquid B is below 5°C. S2: Add the A liquid and B liquid prepared in step S1 into the reaction vessel, start the stirring and cooling cycle, so that the A liquid and B liquid begin to react, and during the reaction process, the temperature of the reaction system is maintained below 5°C; S3: After the reaction in step S2 is completed, continue stirring until no more bubbles are generated in the slurry. Then, perform solid-liquid separation on the slurry after the reaction. After the filter cake is processed, the morphology-controllable nano-cobalt boride powder material is obtained. In step S3, the reaction temperature is kept below 5°C. In step S1, the reducing agent is sodium borohydride, the solution A is an aqueous solution of sodium borohydride, and the concentration of the aqueous solution of sodium borohydride is 0.5-3 M. In step S1, the soluble cobalt salt aqueous solution is one of cobalt chloride solution, cobalt nitrate solution, cobalt sulfate solution, and cobalt acetate solution, and the concentration of the soluble cobalt salt aqueous solution is 0.5-1.5 M. In step S1, the complexing agent is citric acid, sodium citrate, or ammonium citrate; the molar ratio of the soluble cobalt salt to the reducing agent is 1:(2-3); the molar ratio of the complexing agent to the soluble cobalt salt is (0-1):

4. In step S2, liquid A and liquid B are added in the following manner: S21: When liquid B is first poured into the reaction vessel, and then liquid A is added to the reaction vessel by titration to react with liquid B, the nano-cobalt boride powder material in step S3 is spherical nano-cobalt boride powder; or: S22: When liquid A and liquid B are simultaneously added to the reaction vessel by titration, the nano-cobalt boride powder material in step S3 is flower-shaped nano-cobalt boride powder.

2. The method according to claim 1, wherein the method is characterized by, In step S1, the inert gas is one or both of argon and nitrogen.

3. The method according to claim 1, wherein the method is characterized by, In steps S21 and S22, the titration rate is 160-240 mL / min; in step S2, the stirring speed is 300-600 rpm.

4. The method according to claim 1, wherein the method is characterized by, In step S3, the continuous stirring time is 1-2 hours, and the stirring speed is 100-300 rpm.

5. The method for preparing morphology-controllable nano-cobalt boride powder according to claim 1, characterized in that, In step S3, the solid-liquid separation process is positive pressure filtration or negative pressure filtration; the filter cake treatment includes filtering, washing, and drying the filter cake, and the filtration is to separate the solid and liquid by positive or negative pressure to obtain the filter cake; the washing is to wash the filter cake multiple times with deionized water and anhydrous ethanol, wherein the water washing is 3-6 times and the ethanol washing is 1-3 times, and the water washing temperature is 40-80℃; the drying includes drying under inert gas protection or vacuum drying, the drying temperature is 60-100℃, and the drying time is 8-24 h.

6. A morphology-controllable nano-cobalt boride powder, characterized in that, The nano-cobalt boride powder is prepared by the preparation method described in any one of claims 1-5.

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