A method for preparing g-C3N4-doped CuO lithium-ion battery anode material with a sandwich-like morphology

Abstract

The application discloses a preparation method of a lithium ion battery negative electrode material of g-C3N4 doped with CuO with a sandwich-shaped morphology. Firstly, g-C3N4 is prepared by using a thermal polymerization method and calcining melamine as raw material; then, a CuO / C3N4 composite material is obtained by adding g-C3N4 in the process of preparing CuO by using a precipitation method. The preparation process is simple and convenient, and the cost is low. The negative electrode material prepared by the method has a high specific surface area, which is helpful to improve the specific capacity of the material. The g-C3N4 is inserted into the middle of CuO layers, which relieves the volume expansion of CuO during large-current charging and discharging. The CuO / C3N4 composite material has excellent rate performance and charging and discharging cycle stability as a lithium battery negative electrode material.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery anode material preparation, and relates to a method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4 doped with CuO. Background Technology

[0002] As human civilization develops, the demand for energy is increasing. Currently, fossil fuels are the primary source of energy for humanity, making them the most relied-upon resource in production and daily life. Among common chemical energy storage devices, lithium-ion batteries have several advantages, including high energy density, high power density, and good safety performance. However, current technological advancements are placing even higher demands on the performance of lithium-ion batteries.

[0003] The anode material of lithium-ion batteries has a significant impact on the basic characteristics of the battery. Currently, the mainstream anode material is graphite-based materials, and the application of other materials is rare. Graphite-based carbon materials have good charge-discharge cycle performance, but due to their lithium insertion / extraction mechanism, their theoretical specific capacity is very low, making it difficult to meet the high capacity requirements of batteries in some scenarios. In the research of other materials, metal oxides have received widespread attention in the field of lithium-ion battery anode materials due to their advantages of abundant reserves, low price and high specific capacity. However, while metal oxides have high specific capacity, they also have the disadvantage of rapid performance degradation during charge-discharge cycles, mainly due to their poor conductivity and severe volume expansion during charge-discharge.

[0004] CuO, as a negative electrode material for lithium-ion batteries, not only possesses high theoretical capacity, low preparation cost, and simple preparation process, but is also environmentally friendly and highly safe, meeting the future development requirements of lithium-ion batteries. However, it also suffers from the common drawbacks of metal oxides, limiting its application. To address these issues, a sandwich-structured composite material of CuO and g-C3N4 needs to be developed. The unique layered structure provides a large specific surface area, allowing for more thorough contact between the material and the electrolyte. Furthermore, the doping of g-C3N4 effectively improves the poor conductivity of CuO, alleviates the severe volume expansion problem, and enhances the electrochemical performance of the material, giving it greater application potential. Summary of the Invention

[0005] This invention aims to provide a method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4 doped with CuO. First, g-C3N4 is prepared by calcination of melamine using a thermal polymerization method. Then, g-C3N4 is added during the CuO preparation process using a precipitation method to obtain a CuO / C3N4 composite material. The preparation process is simple, convenient, and low in cost. The prepared CuO / C3N4 composite material has excellent rate performance and charge-discharge cycle stability, and has good application potential in the field of lithium battery anode materials.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a lithium-ion battery anode material with a sandwich-like morphology and doped with CuO by g-C3N4 comprises the following steps in sequence:

[0008] (1) Using melamine as the raw material for preparing g-C3N4, it was placed in a crucible and calcined in a muffle furnace by controlled temperature rise. The calcined material was then ground in a mortar to obtain g-C3N4, which was denoted as powder A.

[0009] (2) Dissolve CuSO4·5H2O in a mixed solution of ethanol and distilled water, and add powder A (g-C3N4) to form a mixed solution of CuSO4·5H2O and g-C3N4. Stir the solution magnetically for 1 hour in a constant temperature water bath at 45℃ to obtain solution B.

[0010] In this invention, the water bath heating temperature is crucial. A suitable temperature can prevent the aggregation of structures and avoid affecting the formation of subsequent structures.

[0011] (3) Add surfactant PVP to solution B and continue magnetic stirring for 20 min to obtain solution C;

[0012] (4) Add the diluted ammonia solution dropwise to solution C and continue magnetic stirring for 40 minutes to obtain solution D;

[0013] (5) Prepare a KOH solution of a certain concentration, add the KOH solution dropwise to solution D, continue to stir magnetically for 1 hour, after stirring is completed, let the mixture stand at room temperature for 24 hours, and finally pour off the supernatant alkaline solution to obtain E;

[0014] (6) Wash E with deionized water by centrifugation 3-5 times to make the pH value neutral; then wash it with ethanol 3-5 times, put it in a drying oven for vacuum drying, and grind the obtained sample to obtain powder F after drying.

[0015] (7) Transfer F to a crucible and place it in a muffle furnace for calcination. The calcination is divided into three stages: the first stage is to raise the temperature from room temperature to 130°C and hold it for 0.5-1h; the second stage is to raise the temperature from 130°C to 150°C and hold it for 0.5-1h; the third stage is to raise the temperature from 150°C to 180°C and hold it for 4h. After calcination, place the calcined material in a mortar and grind it to obtain the negative electrode material CuO / C3N4.

[0016] As a limitation of this invention:

[0017] (i) In step (1), the calcination conditions in the muffle furnace are: heating to 550-600℃ at a rate of 5-8℃ / min and holding for 4 hours.

[0018] (ii) In step (2), the volume ratio of ethanol to distilled water in the mixed solution of ethanol and distilled water is 1:1.5, the mass ratio of CuSO4·5H2O and g-C3N4 is 12.5:1, and the concentration of CuSO4·5H2O is controlled to be 0.08-0.1mol / L.

[0019] This invention employs a preparation method that involves adding CuSO4·5H2O and g-C3N4 together to the reaction solution. When g-C3N4 is added, CuO has not yet been generated, so its precursor Cu(OH)2 can grow on the surface of g-C3N4 and then continuously stack up. Since g-C3N4 and Cu(OH)2 have different growth orientations, when they aggregate into clustered particles under the action of surfactant, they exhibit a sandwich structure with sheet-like Cu(OH)2 and g-C3N4 superimposed on each other.

[0020] In this invention, the concentration of CuSO4·5H2O has a significant impact on the formation of the lamellar structure of Cu(OH)2. When the concentration of CuSO4·5H2O in the solution is appropriate, Cu... 2+ If the concentration of CuSO4·5H2O is insufficient to form a large number of crystal nuclei, the Cu(OH)2 crystals will grow on the surface of a few seeds, forming an aggregated lamellar structure. The lamellar structure aggregates under the action of van der Waals forces. However, if the concentration of CuSO4·5H2O is too high, the product will lose its lamellar cluster structure and form a dispersed structure. Therefore, it is necessary to control the concentration of CuSO4·5H2O.

[0021] (iii) In step (3), the concentration of PVP is controlled to be 0.002-0.005 mol / L, and the mass ratio of PVP to g-C3N4 is 1:1-2.

[0022] The concentration of surfactant PVP has a certain influence on the microstructure of materials. Adding a small amount of PVP can better regulate the size of nanosheets and improve the aggregation phenomenon. However, excessive PVP concentration may increase the viscosity of the solution, causing the nanosheets to aggregate excessively and resulting in overly large particles.

[0023] (iv) In step (4), the mass fraction of the diluted ammonia solution is 10%-15%.

[0024] (v) In step (5), the concentration of the added KOH solution is 0.85-1.00 mol / L, and the mass ratio of the added ammonia solution, the added KOH solution, and the added g-C3N4 is 1:2:0.015-0.02.

[0025] When KOH is used as a precipitant, its concentration has a certain impact on the final microstructure of the material because OH... - The reaction affects the nucleation of Cu(OH)₂ grains, OH- Excessive concentration may rapidly generate a large number of crystal nuclei, forming too many dispersed crystals, thus affecting the final microstructure of the product. Therefore, it is necessary to control the concentration of KOH solution. Using a concentration within the range of this application will result in a better sandwich morphology of the prepared composite material.

[0026] (vi) In step (6), the centrifugation speed is 5000-7000 r / min, the centrifugation time is 3-5 min, the vacuum drying temperature is 60℃, and the drying time is 2 h.

[0027] (vii) In step (7), the calcination heating rate is: 10℃ / min for the first stage, 5℃ / min for the second stage, and 5℃ / min for the third stage.

[0028] The main purpose of calcination in this step is to convert Cu(OH)2 into the final desired CuO through thermal decomposition. The calcination temperature, heating rate, and holding time in this step have a crucial impact on the final microstructure and properties of the material. The first stage of calcination involves heating from room temperature to 130℃ and holding for 0.5-1 hour. This stage is the hidden period of the solid-phase decomposition reaction. A rapid heating rate of 10℃ / min is used in this stage to quickly evaporate impurities and enhance the particle activity of the reactants. The second stage of calcination involves heating from 130℃ to 150℃ and holding for 0.5-1 hour. This stage is the activation period and nucleation period of the reaction. The heating rate is 5℃ / min. The reactants are further activated, and the stability of the Cu(OH)2 structure is gradually destroyed at this stage. The hydrogen bonds between the crystal planes break and dehydration begins. The rapid heating rate helps to accelerate the dehydration rate, which promotes the rapid transformation of the orthorhombic Cu(OH)2 into the monoclinic CuO. The product CuO begins to nucleate at this stage. The third stage of calcination involves heating from 150℃ to 180℃ and holding for 4 hours. This stage is the crystal growth period, with a heating rate of 5℃ / min. During this stage, the CuO crystal nuclei grow rapidly, and the decomposition rate of Cu(OH)2 reaches its maximum, forming a lamellar structure of CuO, thus forming the final product CuO / C3N4 composite material. The appropriate temperature in this step can promote the contact between the materials, making the bond between CuO and g-C3N4 sheets stronger through van der Waals forces, and can evaporate the moisture in the materials, making the material structure more stable and helping to improve the capacity performance and cycle stability of the electrode material. However, excessively high calcination temperature may damage the sheet structure of the material. Therefore, the control of the conditions in this step has a great influence on the microstructure of the material and is closely related to the electrochemical performance of the final product.

[0029] In another aspect, the present invention specifies that the negative electrode material is a material formed by inserting sheet-like g-C3N4 into the middle of the layered CuO sheets. The layered CuO has a suitable specific surface area. The insertion of g-C3N4 nanosheets and the doping of nitrogen can generate more electrode / electrolyte contact surfaces and active sites. At the same time, the sandwich structure formed by g-C3N4 and CuO can alleviate the volume expansion during high current charging and discharging and improve its cycle stability.

[0030] The preparation method of this invention is an integral and inseparable whole. Each step must be performed sequentially to obtain the sandwich-shaped CuO / C3N4 product described in this invention. When the sandwich-shaped CuO / C3N4 composite material obtained by this invention is used as a negative electrode material for lithium-ion batteries, its specific capacity decreases from about 704 mAh / g to about 405 mAh / g at a current density ranging from 67 mA / g to 1.3 A / g. When the current density recovers from 1.3 A / g to 67 mA / g, its specific capacity recovers to about 620 mAh / g, showing good rate performance. After 200 charge-discharge cycles at a current density of 500 mA / g, the specific capacity of this material is about 790 mAh / g.

[0031] The technical effects achieved by adopting the above-described technical solution are as follows:

[0032] (1) The size of the sandwich-shaped particles of the active material (CuO / C3N4) obtained by the present invention is appropriate, about 1.5-2μm, and the thickness of each CuO nanosheet is about 30nm. The nanosheets support each other, giving it good structural stability and facilitating the diffusion of Li+ ions, thus promoting the reaction.

[0033] (2) In the active material (CuO / C3N4) obtained by the present invention, the g-C3N4 layered structure is inserted into the gap between CuO layers, which alleviates the volume expansion of the electrode material and improves the cycle performance of the material.

[0034] (3) The active material (CuO / C3N4) nanosheets obtained by the present invention have a large specific surface area, which can enable the electrode material and electrolyte to fully contact and wet, which is beneficial to the penetration of electrolyte and can effectively improve the electrochemical performance of the material.

[0035] (4) The preparation process of this invention is simple, easy to operate and easy to control. The reaction process is green and environmentally friendly. The raw materials are cheap and readily available. The cost is low. The reaction products are stable and easy to store.

[0036] (5) The material prepared by the present invention has high specific capacity and coulombic efficiency, and has good application potential in the field of lithium battery, and is suitable for industrial production and application.

[0037] This invention is applicable to the preparation of lithium-ion battery anode materials.

[0038] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0039] Instruction manual illustrations

[0040] Figure 1 The X-ray diffraction pattern of the CuO / C3N4 composite material synthesized in Example 1 of this invention;

[0041] Figure 2 This is a rate performance diagram of the CuO / C3N4 composite material synthesized in Example 1 of the present invention when used as a negative electrode material for lithium-ion batteries;

[0042] Figure 3 The cycle life diagram of the CuO / C3N4 composite material synthesized in Example 1 of the present invention as a negative electrode material for lithium-ion batteries is shown.

[0043] Figure 4 The image shows the TEM spectrum of the CuO / C3N4 composite material synthesized in Example 1 of this invention.

[0044] Figure 5 This is the SEM image of the CuO / C3N4 composite material synthesized in Example 1 of this invention. Detailed Implementation

[0045] Unless otherwise specified, all reagents used in the following embodiments are commercially available reagents, and all experimental and detection methods used in the following embodiments are existing experimental and detection methods.

[0046] Example 1: A method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO.

[0047] This embodiment describes a method for preparing a lithium-ion battery anode material with a sandwich-like morphology, consisting of g-C3N4 doped CuO, and is carried out in the following order:

[0048] (1) Using melamine as the raw material for preparing g-C3N4, it was placed in a crucible and calcined in a muffle furnace by programmed temperature control. The calcination conditions of the muffle furnace were set as follows: heating to 550℃ at a rate of 5℃ / min and holding for 4h. The calcined material was then ground in a mortar to obtain g-C3N4, which was denoted as powder A1.

[0049] (2) Dissolve CuSO4·5H2O in a mixed solution of ethanol and distilled water (volume ratio of 1:1.5), and add a certain amount of powder A1 (controlling the concentration of CuSO4·5H2O in the solution to 0.08 mol / L, and controlling the mass ratio of CuSO4·5H2O to g-C3N4 to 12.5:1) to form a mixed solution of CuSO4·5H2O and g-C3N4. Stir the solution magnetically for 1 h in a constant temperature water bath at 45℃ to obtain solution B1.

[0050] (3) Add surfactant PVP to solution B1, control the concentration of PVP to be 0.002 mol / L, and the mass ratio of PVP to g-C3N4 to be 1:2. Continue to stir magnetically for 20 min to obtain solution C1.

[0051] (4) Add the diluted 10% ammonia solution dropwise to solution C1 and continue to stir magnetically for 40 minutes to obtain solution D1;

[0052] (5) Prepare a 0.85 mol / L KOH solution. Add the KOH solution dropwise to solution D1, and control the mass ratio of the added ammonia solution (10 wt.%), the added KOH solution, and the added g-C3N4 to be 1:2:0.015. Continue to stir magnetically for 1 hour. After stirring, let the mixture stand at room temperature for 24 hours. Finally, discard the supernatant alkali solution to obtain E1.

[0053] (6) Wash E1 with deionized water by centrifugation 3-5 times to make the pH value neutral; then wash it with ethanol 3-5 times. The centrifugation speed is set to 6000 r / min and the centrifugation time is 5 min. Place it in a drying oven for vacuum drying at 60℃ for 2 h. After drying, grind the obtained sample to obtain powder F1.

[0054] (7) Transfer F1 to a crucible and place it in a muffle furnace for calcination. The calcination is divided into three stages: the first stage is to raise the temperature from room temperature to 130°C at a rate of 10°C / min and hold for 1 hour; the second stage is to raise the temperature from 130°C to 150°C at a rate of 5°C / min and hold for 1 hour; the third stage is to raise the temperature from 150°C to 180°C at a rate of 5°C / min and hold for 4 hours. After calcination, place the calcined material in a mortar and grind it to obtain the negative electrode material CuO / C3N4.

[0055] The product prepared in this embodiment was subjected to XRD, TEM, and SEM tests, as shown below. Figure 1 , Figure 4 and Figure 5 As shown, the prepared product is a CuO / C3N4 composite material with a sandwich morphology.

[0056] The product was used as a lithium battery anode material for electrochemical performance testing. Figure 2 The graph shows the rate performance of the CuO / C3N4 composite material. At current densities ranging from 67 mA / g to 1.3 A / g, the specific capacity of this composite material decreases from approximately 704 mAh / g to approximately 405 mAh / g. When the current density recovers from 1.3 A / g to 67 mA / g, the capacity recovers to approximately 620 mAh / g, indicating good rate performance.

[0057] Figure 3 The diagram shows the cycle life of the CuO / C3N4 composite material. After 200 charge-discharge cycles at a current density of 500 mA / g, its charge-discharge specific capacity is approximately 790 mAh / g.

[0058] Examples 2-4: Preparation method of g-C3N4-doped CuO lithium-ion battery anode material with sandwich morphology

[0059] This embodiment describes a method for preparing a lithium-ion battery anode material with a sandwich-like morphology, g-C3N4 doped with CuO. The preparation steps are similar to those in Example 1, except that the corresponding technical parameters in the preparation process are different, as shown in the table below.

[0060]

[0061]

[0062] Example 5 Comparative Example 1

[0063] To investigate the effect of g-C3N4 doping on the material's performance, this embodiment uses a precipitation method similar to that in Example 1 to prepare a layered pure CuO anode material without g-C3N4 doping. The experimental steps are as follows.

[0064] (1) Dissolve CuSO4·5H2O directly in a mixed solution of ethanol and distilled water in a volume ratio of 1:1.5 (control the concentration of CuSO4·5H2O in the solution to be 0.08 mol / L), and stir the solution magnetically for 1 h in a constant temperature water bath at 45℃.

[0065] (2) Add surfactant PVP to the above solution, control the concentration of PVP to 0.002 mol / L, and continue to stir magnetically for 20 min;

[0066] (3) Add the diluted 10% ammonia solution dropwise to the above solution and continue magnetic stirring for 40 min;

[0067] (4) Prepare a 0.85 mol / L KOH solution. Add the KOH solution dropwise to the above solution, and control the mass ratio of the added ammonia solution (10 wt.%) to the added KOH solution to 1:2. Continue to stir magnetically for 1 hour. After stirring, let the mixture stand at room temperature for 24 hours. Finally, discard the supernatant alkali solution.

[0068] (5) Wash the precipitate with deionized water by centrifugation 3-5 times to make the pH value neutral; then wash it with ethanol 3-5 times, set the centrifugation speed to 6000 r / min, centrifugation time to 5 min, put it in a drying oven for vacuum drying, drying temperature to 60℃, drying time to 2 h, and grind the obtained sample to obtain a powder.

[0069] (6) The powder was transferred to a crucible and placed in a muffle furnace for calcination. The calcination was divided into three stages: the first stage was to raise the temperature from room temperature to 130°C at a rate of 10°C / min and hold for 1 hour; the second stage was to raise the temperature from 130°C to 150°C at a rate of 5°C / min and hold for 1 hour; the third stage was to raise the temperature from 150°C to 180°C at a rate of 5°C / min and hold for 4 hours. After calcination, the calcined material was ground in a mortar to obtain pure CuO anode material.

[0070] The morphology and performance of the anode material prepared in this embodiment were tested. The results showed that the number of nanosheets in the clusters of the lamellar CuO particles prepared in this embodiment was significantly less than that of the CuO / C3N4 composite material. The closely spaced sheets tended to overlap to form thicker nanosheets, thus affecting the specific surface area. The remaining sheets were spaced further apart, and the uniformity of their shape was worse than that of the CuO / C3N4 composite material. Electrochemical performance tests were conducted on the anode material. At current densities of 67 mA / g and 1.3 A / g, the discharge capacities were approximately 406 mAh / g and 167 mAh / g, respectively. In comparison, the specific capacity of pure CuO was lower than that of the CuO / C3N4 composite material, indicating that the doping of g-C3N4 improved the rate performance of the lamellar pure CuO.

[0071] Example 6 Comparative Example 2

[0072] To further investigate the influence of different technical parameters on the product during the preparation of CuO / C3N4, the following experiments were conducted in this embodiment.

[0073] Group A: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (2), the solution added to CuSO4·5H2O and g-C3N4 was distilled water.

[0074] Group B: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (2), the concentration of CuSO4·5H2O was controlled to be 0.2 mol / L.

[0075] Group C: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (2), the mass ratio of CuSO4·5H2O and g-C3N4 was controlled to be 8:1.

[0076] Group D: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (3), the concentration of PVP was controlled to be 0.01 mol / L.

[0077] Group E: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (5), the concentration of the added KOH solution was 1.5 mol / L.

[0078] Group F: CuO / C3N4 was prepared. The preparation process was similar to that in Example 1, except that in step (7), the muffle furnace calcination conditions were set to heat up to 200°C at a rate of 5°C / min and hold for 4 hours.

[0079] Group G: Pure g-C3N4 was prepared as a negative electrode material for lithium batteries. The preparation process was to prepare g-C3N4 material according to the method described in step (1) of Example 1, and to use it as a negative electrode material for electrochemical performance testing. The purpose was to compare its performance difference with that of CuO / C3N4 composite material.

[0080] The products prepared by the above AG group and their electrochemical performance as negative electrode materials are shown in the table below.

[0081]

[0082] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4 doped with CuO, characterized in that, Follow these steps in sequence: (1) Using melamine as the raw material for preparing g-C3N4, it was placed in a crucible and calcined in a muffle furnace by controlled temperature rise. The calcined material was then ground in a mortar to obtain g-C3N4, which was denoted as powder A. (2) Dissolve CuSO4·5H2O in a mixed solution of ethanol and distilled water, and add powder A and stir evenly to form a mixed solution of CuSO4·5H2O and g-C3N4. The volume ratio of ethanol to distilled water in the mixed solution of ethanol and distilled water is 1:1.5, the mass ratio of CuSO4·5H2O and g-C3N4 is 12.5:1, and the concentration of CuSO4·5H2O is 0.08-0.1 mol / L. Stir the solution magnetically for 1 h in a constant temperature water bath at 45℃ to obtain solution B. (3) Add surfactant PVP to solution B, control the concentration of PVP to be 0.002-0.005 mol / L, and the mass ratio of PVP to g-C3N4 to be 1:1-2. Continue to stir magnetically for 20 min to obtain solution C. (4) Add the diluted ammonia solution dropwise to solution C and continue magnetic stirring for 40 minutes to obtain solution D; (5) Add KOH solution dropwise to solution D and continue to stir magnetically for 1 hour. After stirring, let the mixture stand at room temperature for 24 hours. Finally, discard the supernatant alkali solution to obtain E. (6) Wash E with deionized water by centrifugation 3-5 times to make the pH value neutral; then wash with ethanol 3-5 times, put it in a drying oven for vacuum drying, and grind the obtained sample to obtain powder F. (7) Transfer F to a crucible and place it in a muffle furnace for calcination. The calcination is divided into three stages: the first stage is to raise the temperature from room temperature to 130°C and hold it for 0.5-1h; the second stage is to raise the temperature from 130°C to 150°C and hold it for 0.5-1h; the third stage is to raise the temperature from 150°C to 180°C and hold it for 4h. After calcination, the calcined material is placed in a mortar and ground to obtain the negative electrode material CuO / C3N4. The negative electrode material is a material formed by inserting sheet-like g-C3N4 into the middle of the layered CuO sheets.

2. The method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO according to claim 1, characterized in that, In step (1), the calcination in the muffle furnace is carried out at a rate of 5-8℃ / min to 550-600℃ and held for 4 hours.

3. The method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO according to claim 1, characterized in that, In step (4), the mass fraction of the diluted ammonia solution is 10%-15%.

4. The method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO according to claim 1, characterized in that, In step (5), the concentration of the KOH solution is 0.85-1.00 mol / L, and the mass ratio of the diluted ammonia solution, KOH solution, and g-C3N4 is 1:2:0.015-0.

02.

5. The method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO according to claim 1, characterized in that, In step (6), the centrifugation speed is 5000-7000 r / min, the centrifugation time is 3-5 min, the vacuum drying temperature is 60℃, and the drying time is 2 h.

6. The method for preparing a lithium-ion battery anode material with a sandwich-like morphology of g-C3N4-doped CuO according to claim 1, characterized in that, In step (7), the calcination heating rate is: 10℃ / min for the first stage, 5℃ / min for the second stage, and 5℃ / min for the third stage.

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