Cobalt phosphoselenide@carbon hollow nanocube box composites, preparation and applications thereof

Abstract

The application discloses a cobalt phosphorous selenide@carbon hollow nanometer cubic box composite material and a preparation method and application thereof in preparation of a lithium ion battery negative electrode. The composite material is in a cubic shape and hollow inside; the composite material comprises a carbon hollow nanometer cubic box shell and cobalt phosphorous selenide particles encapsulated on the inner wall of the carbon hollow nanometer cubic box shell. The preparation method comprises the following steps: first, synthesizing a solid Co-Co PBA precursor; then, coating polydopamine on the surface of the Co-Co PBA precursor; then, carbonizing the Co-Co PBA precursor; in the carbonizing process, the polydopamine is decomposed to form a carbon hollow nanometer cubic box, and the Co-Co PBA is decomposed into cobalt particles; finally, synchronously gas-phase phosphorous selenization is carried out to obtain the CoPSe@carbon hollow nanometer cubic box composite material. The composite material has the characteristics of stable cycle performance, high specific capacity and excellent rate performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and in particular to a cobalt selenide phosphide (CoPSe)@carbon (C) hollow nanocube box composite material, its preparation, and its application in preparing a negative electrode of a lithium-ion battery. Background Art

[0002] Lithium-ion batteries are currently the best energy storage system and are widely used in various portable devices, electric vehicles, and smart grids. However, commercial graphite, the mainstream negative electrode material, has reached its performance limit (372mAh g -1 ), which cannot meet the increasingly higher power and energy density, rate performance and safety requirements of lithium-ion batteries.

[0003] Transition metal selenides / phosphides have the advantages of high theoretical capacity and low cost, and have become a lithium-ion battery negative electrode material that has attracted much attention in recent years. People have improved the lithium storage performance of transition metal selenides / phosphides through methods such as nanostructure engineering, composite carbon materials, and ion doping. However, these works mainly focus on binary materials. For example, the invention patent with publication number CN114744191A discloses a cobalt phosphide negative electrode material, and the invention patent with publication number CN114229805A discloses a nitrogen-doped porous carbon-coated cobalt diselenide composite material.

[0004] However, the application of single-phase ternary materials in lithium-ion batteries has been rarely reported. Single-phase ternary materials contain two different anions. Within the material, the two anions are uniformly mixed, forming a large number of atomic-level interfaces. The coexistence of the two anions can further modulate the material's electronic structure and influence its physical and chemical properties. In addition, due to the different redox potentials, the asynchronous reactions triggered by the different redox potentials of the two anions can effectively buffer the internal stress caused by lithium-ion insertion and deinsertion, which is beneficial for improving the cycling performance of lithium-ion batteries.

[0005] Currently, there is little research on the synthesis methods, composite material structure design, and application of CoPSe in lithium-ion batteries. Yang JH has published a report on sodium-ion / potassium-ion batteries (Adv. Mater. 2021, 33, 2007262), which discloses a composite material with CoPSe nanoparticles embedded in a nitrogen-doped carbon matrix derived from a layered metal-organic framework material. Summary of the Invention

[0006] In response to the technical problems existing in this field, the present invention provides a CoPSe@C hollow nanocube box composite material with the characteristics of unique structure, excellent performance and simple synthesis process.

[0007] The present invention is achieved through the following technical solutions:

[0008] A cobalt selenide phosphide@carbon hollow nanocube box composite material is cube-shaped and hollow inside. The cobalt selenide phosphide@carbon hollow nanocube box composite material comprises a carbon hollow nanocube box-shaped shell and cobalt selenide phosphide particles encapsulated on the inner wall of the carbon hollow nanocube box-shaped shell, and the carbon hollow nanocube box-shaped shell also has gaps inside.

[0009] Preferably, the box-shaped shell of the carbon hollow nanocube is formed by carbonizing polydopamine.

[0010] Preferably, the cobalt selenide phosphide particles are formed by carbonizing and phosphoselenizing a Co-Co PBA precursor.

[0011] Preferably, the preparation method of the Co-Co PBA precursor is: dissolving Co(NO3)2·6H2O and sodium citrate dihydrate in deionized water to obtain solution A; dissolving K3[Co(CN)6] in deionized water to obtain solution B; injecting solution B into solution A, stirring the resulting solution uniformly at room temperature, and aging for 10-30 hours; centrifuging the product obtained after aging, washing, and drying to obtain the Co-Co PBA precursor.

[0012] Preferably, the diameter of the cobalt selenide phosphide particles is 10-300 nm.

[0013] Preferably, the side length of the box-shaped shell of the hollow carbon nanocube is 50-1000 nm, and the wall thickness is 10-150 nm.

[0014] Preferably, in the cobalt selenide phosphide@carbon hollow nanocube box composite material, the mass proportion of the cobalt selenide phosphide particles is 10-95%, and the rest is carbon.

[0015] The present invention also provides a method for preparing the CoPSe@carbon hollow nanocube box composite material. The preparation method has a reliable route and a simple operation process.

[0016] A method for preparing the cobalt selenide phosphide@carbon hollow nanocube box composite material is characterized by comprising the steps of:

[0017] (1) Prepare solution A: Dissolve Co(NO3)2·6H2O and sodium citrate dihydrate in deionized water;

[0018] Prepare solution B: dissolve K3[Co(CN)6] in deionized water;

[0019] Solution B was injected into solution A, and the resulting solution was stirred uniformly at room temperature and aged for 10-30 hours; the product obtained after aging was centrifuged, washed, and dried to obtain a Co-Co PBA precursor;

[0020] (2) Dispersing the Co-Co PBA precursor obtained in step (1) in deionized water; adding tris(hydroxymethyl)aminomethane, stirring and dispersing thoroughly, and then adding dopamine hydrochloride, stirring for 3-10 hours; centrifuging the obtained product, washing, and drying to obtain Co-Co PBA@PDA; heating the obtained Co-Co PBA@PDA to 400-600°C under an argon atmosphere and keeping the temperature for 1-3 hours to obtain Co@carbon hollow nanocube boxes;

[0021] (3) The Co@carbon hollow nanocube box, red phosphorus and selenium powder obtained in step (2) are ground evenly in a mass ratio of 1.25:1:2, and the resulting mixture is heated to 550-650°C in a sealed vacuum environment for vapor phase phosphorus selenization, and kept warm for 3-10 hours to remove excess P and Se to obtain the CoPSe@carbon hollow nanocube box composite material.

[0022] The preparation method provided by the present invention first synthesizes solid Co-Co Prussian blue cubes (Co-Co PBA precursor), then coats their surface with a layer of polydopamine. This is followed by carbonization. During the carbonization process, the polydopamine decomposes to form hollow carbon nanocube boxes. The Co-Co Prussian blue cubes decompose into metallic cobalt particles, which are encapsulated on the inner walls of the hollow nanocube boxes. Finally, through a simultaneous vapor-phase phosphoselenide method, isoproton and selenium infiltration is performed to obtain the CoPSe@carbon hollow nanocube box composite material. This method can improve the specific capacity and cycle performance of CoPSe.

[0023] Preferably, in step (1), when preparing solution A, the ratio of the amount of Co(NO3)2·6H2O, sodium citrate dihydrate and deionized water is 0.06-0.9 mmol:0.09-1.35 mmol:20 mL.

[0024] Preferably, in step (1), when preparing solution B, the ratio of K3[Co(CN)6] to deionized water is 0.04-0.6 mmol:20 mL.

[0025] Preferably, in step (2), relative to 120 mg of the Co-Co PBA precursor, the amount of deionized water used is 144 mL, the amount of tris(hydroxymethyl)aminomethane used is 35-261 mg, and the amount of dopamine hydrochloride used is 7.2-54 mg.

[0026] Preferably, in step (2), the obtained Co-Co PBA@PDA is placed in a tube furnace and heated at 2°C·min in flowing argon. -1 The temperature was raised to 400-600℃ at a rate of 1-3h and kept at that temperature to obtain Co@carbon hollow nanocube boxes.

[0027] Preferably, in step (3), the obtained mixture is sealed in a quartz tube (length 170 mm, inner diameter 13 mm), vacuum-sealed, and the quartz tube is heated to 600°C and kept warm for 3-10 hours at a heating rate of 2°C min -1 .

[0028] Preferably, in step (3), after the reaction is carried out by heat preservation, the obtained product is placed in a tube furnace and heated to 400-600° C. in flowing argon and kept warm for 0.5-2 h to remove excess P and Se.

[0029] The present invention also provides the use of the CoPSe@carbon hollow nanocube box composite material in preparing a negative electrode of a lithium ion battery.

[0030] In one preferred embodiment, the CoPSe@C hollow nanocube box composite material of the present invention is used to prepare a lithium-ion battery negative electrode: the CoPSe@C hollow nanocube box composite material, acetylene black conductive agent, and PVDF binder are weighed at a mass ratio of 7:1.5:1.5, PVDF is dissolved in an appropriate amount of N-methylpyrrolidone and stirred until completely dissolved. The ground active material and acetylene black are then added to the solution, and stirring is continued to ensure that the slurry is uniformly mixed. The slurry is then evenly coated on a circular copper foil (diameter 12 mm), dried in a vacuum oven at 100°C, and finally flattened on a tablet press at a pressure of 10 MPa to produce an electrode sheet.

[0031] In a glove box filled with high-purity argon, the prepared electrode sheet, lithium sheet, and separator were assembled into a CR2025 button-type lithium-ion battery. The electrolyte was an EC / DMC solution containing 1 mol / L LiPF6. The charge-discharge and cycling performance of the lithium-ion battery was tested using a Xinwei battery testing system.

[0032] The present invention can obtain a CoPSe@C hollow nanocube box composite material with high specific capacity, excellent cycle performance and excellent rate performance.

[0033] Compared with the prior art, the present invention has the following significant technical effects:

[0034] 1) Since the cobalt particles decomposed after the carbonization of Co-Co Prussian blue are adhered to the inner wall of the polydopamine-derived carbon box, the CoPSe generated thereafter is also attached to the inner surface of the carbon wall. The combination of carbon and CoPSe significantly improves the conductivity of CoPSe. At the same time, the CoPSe particles hanging on the inner surface of the carbon wall can expand and contract toward the internal voids, and have high cycle stability. In addition, the CoPSe particles hanging on the inner surface of the carbon wall have a large amount of external surface exposed, which can maximize the surface area in contact with the electrolyte, which significantly increases the number of electrochemically active sites of the material, which is beneficial to improving the electrochemical reaction ability and specific capacity of CoPSe. This unique structure takes into account the improvement of the conductivity, structural stability and electrochemical activity of CoPSe, which is a new feature that the CoPSe reported by Yang JH that is tightly embedded in the carbon nanosheet does not have.

[0035] 2) This invention achieves the equal penetration of P and Se into the interior of the amorphous carbon box, where they successfully combine with metallic cobalt to form CoPSe particles. The difficulty of gaseous P and Se penetrating the amorphous carbon wall and combining with metallic cobalt in equal proportions within the confines of the hollow carbon box to form CoPSe is greater than that of simple phosphiding and selenidation. If the concentrations of P and Se within the carbon box differ significantly, single-phase CoPSe cannot be formed, but instead a mixture of CoSe2 and CoP is formed.

[0036] On the one hand, the amorphous carbon wall derived from different raw materials and its thickness have a great influence on the transmittance of gas-phase P and Se. This study found that the amorphous carbon decomposed from polydopamine, combined with appropriate carbon wall thickness control and carbon hollow cube box internal space size control, under the combined effect of the above-mentioned process factors, can achieve the penetration of gas-phase P and Se and successfully synthesize CoPSe.

[0037] Furthermore, the initial mass ratio of elemental P and Se also affects the ratio of gas-phase P and Se permeating the amorphous carbon walls. The mass ratio of elemental P and Se powder to the Co@C nanocubes influences the ratio of Co, P, and Se in the cobalt phosphoselenide product. The present invention specifically states that a mass ratio of elemental P and Se powder of 1:2, and a mass ratio of 1.25:1:2 for the Co@C hollow nanocubes, red phosphorus, and selenium powder, allows for equal permeation of P and Se through the carbon walls and their combination with cobalt to form CoPSe.

[0038] 3) During the phosphoselenization process, the original large metal cobalt particles will decompose into small nanoparticles. This makes the particle size of CoPSe smaller than that of metal cobalt particles, shortening the lithium ion insertion and extraction path and accelerating the electrochemical reaction kinetics. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a scanning electron microscope (SEM) photograph of the Co-Co Prussian blue prepared in Example 1;

[0040] Figure 2 This is the SEM image of Co-Co PBA@PDA prepared in Example 1;

[0041] Figure 3 This is the SEM image of the Co@carbon hollow nanocube box prepared in Example 1;

[0042] Figure 4 TEM image of the Co@carbon hollow nanocube box prepared in Example 1;

[0043] Figure 5 This is the SEM image of the CoPSe@carbon hollow nanocube box prepared in Example 1;

[0044] Figure 6 TEM image of the CoPSe@carbon hollow nanocube box prepared in Example 1;

[0045] Figure 7 HRTEM image of the CoPSe@carbon hollow nanocube box prepared in Example 1;

[0046] Figure 8 This is the XRD pattern of the CoPSe@carbon hollow nanocube box prepared in Example 1;

[0047] Figure 9 This is the thermogravimetric curve of the CoPSe@carbon hollow nanocube box prepared in Example 1 under air;

[0048] Figure 10 The CoPSe@carbon hollow nanocube box prepared in Example 1 was heated to a current density of 1A g -1 Cycle performance diagram. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are intended to illustrate the present invention and are not intended to limit the scope of the invention. The operating methods in the following examples where no specific conditions are specified are generally performed under conventional conditions or as recommended by the manufacturer.

[0050] Example 1

[0051] (1) 0.6 mmol Co(NO3)2·6H2O and 0.9 mmol sodium citrate dihydrate were dissolved in 20 ml of deionized water and stirred at room temperature for 10 min to form solution A. 0.4 mmol K3[Co(CN)6] was dissolved in 20 ml of deionized water to form solution B. Solution B was quickly poured into solution A. The mixed solution was stirred at room temperature for 5 min and then allowed to stand for 20 h. The product was separated by centrifugation, rinsed twice with deionized water and ethanol, and dried at 60°C to obtain Co-Co Prussian blue (PBA).

[0052] (2) Take 120 mg of Co-Co PBA precursor prepared in step (1) and disperse it in 144 ml of deionized water. Add 174 mg of tris(hydroxymethyl)aminomethane and ultrasonicate for 10 min. Then add 36 mg of dopamine hydrochloride and stir for 6 h. Finally, centrifuge the black precipitate, wash with deionized water and ethanol, and dry at 60 ° C. The product (Co-Co PBA@PDA) is placed in a tube furnace and heated at 2 ° C min in flowing Ar. -1 The temperature was raised to 500 °C at a rate of 100 °C, kept at this temperature for 2 h, and then cooled to room temperature to obtain black Co@C hollow nanocube boxes.

[0053] (3) Grind 50 mg of the Co@C hollow nanocube box prepared in step (2) with 40 mg of red phosphorus and 80 mg of selenium powder. Then, seal the mixed material in a quartz tube (length 170 mm, inner diameter 13 mm), evacuate and seal, and heat the quartz tube to 600 °C for 6 h at a heating rate of 2 °C min -1 After the product was taken out of the quartz tube, it was placed in a tube furnace and heated to 500°C under argon protection for 1 hour to remove excess P and Se, obtaining CoPSe@C hollow nanocube boxes.

[0054] Figure 1 This is the SEM image of Co-Co PBA, showing a typical solid cubic structure with a cube side length of 600-900nm.

[0055] Figure 2 This is the SEM image of Co-Co PBA@PDA. The cubic morphology remains unchanged, but the edges become rounded.

[0056] Figure 3 This is an SEM photo of a Co@C hollow nanocube box. After carbonization, all the cube structures are intact and undamaged. You can see a seemingly transparent film on the surface of the cube, with many nanoparticles adhered underneath.

[0057] Figure 4This is a TEM image of a Co@C hollow nanocube box, showing the hollow interior of the cube. PDA is carbonized to form a thin carbon wall, approximately 40 nm thick. Numerous metallic cobalt nanoparticles, formed by the decomposition of Co-CoPBA, are adhered to the inner surface of the carbon wall. These metallic cobalt nanoparticles range in size from 20 to 170 nm.

[0058] Figure 5 This is an SEM image of a CoPSe@C hollow nanocube box. After simultaneous vapor-phase phosphorus selenide treatment, the particles under the transparent carbon wall become coarser.

[0059] Figure 6 This is its TEM photo. The original large metal cobalt particles decompose into small particles with a size of about 50-120nm after phosphoselenization. The remaining trace phosphorus and selenium aggregate the CoPSe together.

[0060] Figure 7 is a HRTEM image of a CoPSe@C hollow nanocube box, showing disordered amorphous carbon and particles with lattice fringes with a lattice spacing of 0.56 nm. The fringes correspond to the (002) crystal plane of cubic phase CoPSe, proving the formation of CoPSe.

[0061] Figure 8 This is the XRD spectrum of the CoPSe@C hollow nanocube box. All diffraction peaks correspond well to the fitted spectrum of CoPSe. There are no diffraction peaks corresponding to cobalt selenide, cobalt phosphide, Co-Co PBA, or metallic cobalt, once again proving the successful synthesis of CoPSe.

[0062] Figure 9 This is the thermogravimetric curve result of CoPSe@C hollow nanocube box in air. It can be calculated that the content of CoPSe in the composite is 86.96%.

[0063] The CoPSe@C hollow nanocube box composite material of the present invention was used to make a lithium-ion battery negative electrode: the CoPSe@C hollow nanocube box composite material, acetylene black conductive agent, and PVDF binder were weighed at a mass ratio of 7:1.5:1.5. The PVDF was dissolved in an appropriate amount of N-methylpyrrolidone and stirred until completely dissolved. The ground active material and acetylene black were then added to the solution, and stirring was continued to ensure a uniform slurry. The slurry was then evenly coated onto a circular copper foil (12 mm diameter), dried in a vacuum oven at 100°C, and finally flattened on a tablet press at a pressure of 10 MPa to produce an electrode sheet.

[0064] In a glove box filled with high-purity argon, the prepared electrode sheet, lithium sheet, and separator were assembled into a CR2025 button-type lithium-ion battery. The electrolyte was an EC / DMC solution containing 1 mol / L LiPF6. The charge-discharge and cycling performance of the lithium-ion battery was tested using a Xinwei battery testing system.

[0065] Figure 10 The CoPSe@C hollow nanocube box prepared in Example 1 was heated to a current density of 1 A g -1 The cycling performance of the CoPSe@C hollow nanocube box is stable, with a discharge capacity of 885 mAh g at the 1000th cycle. -1 .

[0066] The Co@C hollow nanocube boxes were phosphated separately to obtain CoP@C hollow nanocube boxes and the CoSe2@C hollow nanocube boxes were selenized separately. The only difference between the preparation process and the CoPSe@C hollow nanocube boxes prepared in Example 1 is that selenium and phosphorus were not added.

[0067] Under the same test conditions, their discharge capacities were only 152 and 157 mAh g -1 The specific capacity of the CoPSe@C hollow nanocube box is several times that of the CoP@C hollow nanocube box and the CoSe2@C hollow nanocube box, and its performance is better.

[0068] In addition, the specific capacity and cycle performance of the CoPSe@C hollow nanocube box are also better than those of a cobalt phosphide negative electrode material reported in the invention patent publication number CN114744191A at a current density of 0.5A g -1 Discharge capacity after 300 cycles <100mAh g -1 , which is also better than the carbon nanotube nitrogen-carbon doped cobalt phosphide nanocube material reported in the invention patent publication number CN114229832A at a current density of 0.1A g -1 The discharge capacity after 100 cycles is 494.68 mAh g -1 , which is better than the nitrogen-doped porous carbon-coated cobalt diselenide composite material reported in the invention patent with publication number CN114229805A at a current density of 0.2Ag -1 Discharge capacity after 300 cycles: 644 mAh g -1 , which is better than the transition metal selenide-carbon composite material reported in the invention patent with publication number CN113666344A at a current density of 0.05Ag -1 , the first week discharge capacity is 740mAh g -1 , less than 200mAh g after 180 cycles -1 .

[0069] Example 2

[0070] (1) 0.6 mmol Co(NO3)2·6H2O and 0.9 mmol sodium citrate dihydrate were dissolved in 20 ml of deionized water and stirred at room temperature for 10 min to form solution A. 0.4 mmol K3[Co(CN)6] was dissolved in 20 ml of deionized water to form solution B. Solution B was quickly poured into solution A. The mixed solution was stirred at room temperature for 5 min and then allowed to stand for 20 h. The product was separated by centrifugation, rinsed twice with deionized water and ethanol, and dried at 60°C to obtain Co-Co Prussian blue (PBA).

[0071] (2) Take 120 mg of Co-Co PBA precursor prepared in step (1) and disperse it in 144 ml of deionized water. Add 139 mg of tris(hydroxymethyl)aminomethane and ultrasonicate for 10 min. Then add 29 mg of dopamine hydrochloride and stir for 6 h. Finally, centrifuge the black precipitate, wash with deionized water and ethanol, and dry at 60 ° C. The product (Co-Co PBA@PDA) is placed in a tube furnace and heated at 2 ° C min in flowing Ar. -1 The temperature was raised to 500 °C at a rate of 100 °C, kept at this temperature for 2 h, and then cooled to room temperature to obtain black Co@C hollow nanocube boxes.

[0072] The subsequent process is the same as that in Example 1.

[0073] The structure of the product CoPSe@C hollow nanocube box is similar to that of Example 1, with the main difference being that the carbon wall thickness of the C hollow nanocube box becomes about 30 nm, and the mass proportion of CoPSe in the composite material increases to 89%.

[0074] Example 3

[0075] (1) 0.4 mmol Co(NO3)2·6H2O and 0.6 mmol sodium citrate dihydrate were dissolved in 20 ml of deionized water and stirred at room temperature for 10 min to form solution A. 0.27 mmol K3[Co(CN)6] was dissolved in 20 ml of deionized water to form solution B. Solution B was quickly injected into solution A. The mixed solution was stirred at room temperature for 5 min and then allowed to stand for 20 h. The product was separated by centrifugation, rinsed twice with deionized water and ethanol, and dried at 60°C to obtain Co-Co PBA.

[0076] The subsequent process is the same as that in Example 1.

[0077] The structure of the product CoPSe@C hollow nanocube box is similar to that of Example 1, with the main difference being that the C hollow nanocube box becomes smaller, with a side length of 400-650 nm and a carbon wall thickness of approximately 50 nm; the mass proportion of CoPSe in the composite material is reduced to 81%.

[0078] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. Application of a cobalt selenide phosphide@carbon hollow nanocube box composite material in preparing a negative electrode for a lithium ion battery, characterized in that: The cobalt selenide phosphide@carbon hollow nanocube box composite material is in a cubic shape and hollow inside; The cobalt selenide phosphide@carbon hollow nanocube box composite material comprises a carbon hollow nanocube box-shaped shell and cobalt selenide phosphide particles encapsulated on the inner wall of the carbon hollow nanocube box-shaped shell, and the carbon hollow nanocube box-shaped shell also has gaps left inside; the diameter of the cobalt selenide phosphide particles is 10-300 nm; In the cobalt selenide phosphide@carbon hollow nanocube box composite material, the mass proportion of the cobalt selenide phosphide particles is 10-95%, and the rest is carbon; The preparation method of the cobalt selenide phosphide@carbon hollow nanocube box composite material comprises the following steps: (1) Prepare solution A: Dissolve Co(NO3)2·6H2O and sodium citrate dihydrate in deionized water; Prepare solution B: dissolve K3[Co(CN)6] in deionized water; Solution B was injected into solution A, and the resulting solution was stirred uniformly at room temperature and aged for 10-30 hours; the product obtained after aging was centrifuged, washed, and dried to obtain a Co-Co PBA precursor; (2) dispersing the Co-Co PBA precursor obtained in step (1) in deionized water; Tris(hydroxymethyl)aminomethane) was added, stirred and dispersed thoroughly, and then dopamine hydrochloride was added and stirred for 3-10 hours. The resulting product was centrifuged, washed, and dried to obtain Co-Co PBA@PDA. The obtained Co-Co PBA@PDA was heated to 400-600°C under an argon atmosphere and kept warm for 1-3 hours to obtain Co@carbon hollow nanocube boxes. (3) The Co@carbon hollow nanocube box, red phosphorus and selenium powder obtained in step (2) are ground evenly in a mass ratio of 1.25:1:2, and the resulting mixture is heated to 550-650°C in a sealed vacuum environment for vapor phase phosphorus selenization, and kept warm for 3-10 hours to remove excess P and Se to obtain a CoPSe@carbon hollow nanocube box composite material.

2. The use according to claim 1, characterized in that The side length of the box-shaped shell of the hollow carbon nanocube is 50-1000 nm, and the wall thickness is 10-150 nm.

3. The use according to claim 1, characterized in that In step (1): When preparing solution A, the ratio of the amount of Co(NO3)2·6H2O, sodium citrate dihydrate and deionized water is 0.06-0.9 mmol:0.09-1.35 mmol:20 mL; When preparing solution B, the ratio of K3[Co(CN)6] to deionized water is 0.04-0.6 mmol:20 mL.

4. The use according to claim 1, characterized in that In step (2), relative to 120 mg of the Co-CoPBA precursor, the amount of deionized water used is 144 mL, the amount of tris(hydroxymethyl)aminomethane used is 35-261 mg, and the amount of dopamine hydrochloride used is 7.2-54 mg.

Images