Gold-loaded porous silicon-coated carbon nitride negative electrode material as well as preparation method and application thereof
The gold-loaded porous silicon@carbon nitride anode material addresses the structural instability of silicon-based anodes by stabilizing volume changes and enhancing conductivity, resulting in high capacity and stable performance for lithium-ion batteries.
Patent Information
- Application Number
- CN202510478147.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-07-15
AI Technical Summary
The theoretical capacity limitation of traditional graphite negative electrode materials cannot meet the needs of modern society. At the same time, the structural damage and electrode failure of silicon-based negative electrode materials during charging and discharging are caused by volume changes.
The gold-loaded porous silicon @ carbon nitride negative electrode material is used to regulate the volume change of the silo through gold loading and carbon nitride coating, and improve conductivity, and combine the porous nanostructure to increase the specific surface area to improve electrochemical performance.
It has achieved high specific capacity and cycle stability, met the energy storage needs of modern society, and has broad commercial prospects.
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of nano lithium battery anode materials, and more specifically, it relates to a gold-loaded porous silicon@carbon nitride anode material, its preparation method and application. Background Art
[0002] Lithium-ion batteries are a type of efficient and rechargeable secondary battery. Through the reversible insertion and extraction of lithium ions between the positive and negative electrodes, energy storage and release are achieved, and they are widely used in fields such as consumer electronics, electric vehicles, aerospace, and renewable energy storage.
[0003] Traditional lithium-ion batteries are rechargeable battery systems based on graphite as the anode, transition metal oxides as the cathode, and liquid organic electrolytes. Their technology maturity is high, and they are widely used in fields such as consumer electronics, power tools, and early electric vehicles. However, due to the limitation of the theoretical capacity (372 mAh / g) of traditional graphite anodes, they can no longer meet the needs of modern society.
[0004] Silicon-based anode materials are new lithium-ion battery anode materials with silicon as the main active substance, and energy storage is achieved through the alloying / dealloying reaction between silicon and lithium ions. Currently, the theoretical capacity of silicon-based anode materials is as high as 4200 mAh / g, which is more than 10 times that of traditional graphite anodes (372 mAh / g), and is regarded as the key material to break through the energy density bottleneck of lithium-ion batteries.
[0005] Although silicon has a high theoretical capacity, it will undergo a huge volume change (>300%) during the charge and discharge process. This change will cause the destruction of the material structure and particle pulverization, and then lead to rapid attenuation of the electrode capacity and electrode failure. Summary of the Invention
[0006] In order to improve the stability of silicon-based anode materials during the charge and discharge process, this application provides a gold-loaded porous silicon@carbon nitride anode material, its preparation method and application.
[0007] In the first aspect, this application provides a preparation method of a gold-loaded porous silicon@carbon nitride anode material, adopting the following technical solution: A preparation method of a gold-loaded porous silicon@carbon nitride anode material, comprising the following steps: (1) Mix chloroauric acid, organosilicon, and an oxalic acid aqueous solution, and stir and react at 60-80 °C for 1-2 h to obtain a silicon-containing precursor; (2) Mix the template agent and the solvent, add the silicon-containing precursor and carbon nitride nanosheets, first stir and mix for 2-3 h, then cast on a petri dish, and finally age at 100-120 °C for 36-48 h to obtain a uniform thin film; (3) Under inert gas conditions, heat the uniform thin film at 400 - 500 °C for 5 - 7 h to obtain gold-loaded porous silica@carbon nitride; (4) Under inert atmosphere conditions, heat gold-loaded porous silica@carbon nitride and a reducing agent from 20 - 25 °C to 700 - 850 °C at a heating rate of 0.5 - 1.0 °C / min and calcine for 4 - 6 h to obtain gold-loaded porous silicon@carbon nitride.
[0008] By adopting the above technical solutions, first prepare gold-loaded porous silica through droplet template orientation control, then prepare gold-loaded porous silica@carbon nitride through coating, and finally prepare gold-loaded porous silicon@carbon nitride by reduction method. On the one hand, the gold loading and the coating of carbon nitride can reduce the silicon content in the anode material, effectively control the volume change of the anode material during charge and discharge, and improve the stability of the anode material; on the other hand, the gold loading and the coating of carbon nitride can increase the conductivity of the anode material. At the same time, the porous nanostructure of silicon can increase the specific surface area of the anode material, increase the contact area between the anode material and the electrolyte, increase the reaction sites of the anode material, and thus improve the electrochemical performance of the material.
[0009] Preferably, in the step (1), the molar ratio of the chloroauric acid and the organosilicon is (0.01 - 0.05):3.
[0010] By adopting the above technical solutions, by regulating the gold loading amount, the distribution of gold on the silicon surface can be effectively adjusted, thereby affecting its conductivity.
[0011] Preferably, in the step (1), the chloroauric acid is one or more of chloroauric acid, fluoroauric acid and bromoauric acid.
[0012] Preferably, in the step (1), the organosilicon is one or two of tetraethyl orthosilicate and tetrabutyl orthosilicate.
[0013] Preferably, in the step (1), the preparation method of carbon nitride is: calcine melamine at 500 - 600 °C for 4 - 6 h, cool to obtain carbon nitride; mix carbon nitride and hydrochloric acid, and carry out hydrothermal reaction at 120 - 140 °C for 4 - 6 h to obtain carbon nitride nanosheets.
[0014] Preferably, in the step (2), the template agent is polyvinylpyrrolidone, and the solvents are ethylene glycol and tetrahydrofuran.
[0015] Preferably, the molar ratio of the silicon-containing precursor and the carbon nitride nanosheets is 30:(0.6 - 2); the volume ratio of polyvinylpyrrolidone, ethylene glycol and tetrahydrofuran is (10 - 12):1:1.
[0016] By adopting the above technical solutions, by regulating the molar ratio of the silicon precursor to carbon nitride, the coating amount of carbon nitride on silicon can be adjusted, thereby affecting the conductivity and electrochemical performance of the material. At the same time, by using polyvinylpyrrolidone as a template agent and controlling its dosage, a uniform thin film with uniform pores can be formed after aging, which is beneficial to improving the conductivity and electrochemical performance of the material.
[0017] Preferably, in the steps (3) and (4), the inert gas is one or both of argon or nitrogen.
[0018] Preferably, in the step (4), the reducing agent is one or more of magnesium powder, aluminum powder and boron.
[0019] In a second aspect, the present application provides a gold-loaded porous silicon@carbon nitride anode material, adopting the following technical solution: A gold-loaded porous silicon@carbon nitride anode material is prepared by the preparation method of the above gold-loaded porous silicon@carbon nitride anode material.
[0020] By adopting the above technical solutions, the gold-loaded porous silicon@carbon nitride prepared by the present application enables the silicon-carbon material to exhibit a high specific capacity while ensuring the stability during the cycling process, and has broad commercial prospects.
[0021] In a third aspect, the present application provides an application of a gold-loaded porous silicon@carbon nitride anode material, adopting the following technical solution: An application of a gold-loaded porous silicon@carbon nitride anode material in a lithium battery anode.
[0022] By adopting the above technical solutions, the gold-loaded porous silicon@carbon nitride of the present application has both a high specific capacity and high stability, can be applied in a lithium battery anode, realizes energy storage and release, meets the needs of modern society, and has broad commercial prospects.
[0023] In summary, the present application has the following beneficial effects: The present application first uses gold-loaded porous silicon and then coats it with carbon nitride, enabling the silicon-carbon material to exhibit a high specific capacity while ensuring the stability during the cycling process; at the same time, the porous nano-structure of the porous silicon can increase the specific surface area of the anode material, increase the contact area between the anode material and the electrolyte, increase the reaction sites of the anode material, and thus improve the electrochemical performance of the anode material. Description of the Drawings
[0024] Figure 1 It is the cycling life diagram of the gold-loaded porous silicon@carbon nitride anode material in Example 1; Figure 2 It is the cycling life diagram of the gold-loaded porous silicon@carbon nitride anode material in Example 2; Figure 3 Cycling life graph of the Au-loaded porous silicon@carbon nitride anode material for Example 3. Detailed implementation manners
[0025] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments.
[0026] The initial discharge specific capacity and the discharge specific capacity after 100 cycles of the Au-loaded porous silicon@carbon nitride anode material prepared in the embodiments of the present application and the silicon anode material prepared in the comparative example are detected, and the capacity retention rate is calculated.
[0027] The detection method is as follows: Constant current charge-discharge test, under the condition of a current density of 1 A / g, the charge-discharge voltage window is 0.005 - 2 V.
[0028] The calculation formula of the capacity retention rate is: Capacity retention rate = (discharge specific capacity after 100 cycles / initial discharge specific capacity) × 100%. Embodiments
[0029] Embodiment 1 A preparation method of an Au-loaded porous silicon@carbon nitride anode material, comprising the following steps: (1) Add oxalic acid (0.9 g, 0.01 mol) to deionized water (30 mL), stir and mix at 60 °C for 2 h to obtain an oxalic acid aqueous solution; add chloroauric acid (0.118 g, 0.3 mmol) and tetraethyl orthosilicate (0.067 mL, 0.03 mol) to the oxalic acid aqueous solution, stir and mix at 60 °C for 2 h, and then cool to room temperature to obtain a silicon-containing precursor.
[0030] Calcine melamine (1 g, 7.94 mmol) at 500 °C for 6 h, and cool to room temperature to obtain carbon nitride (0.3807 g, 3.96 mmol); carry out a hydrothermal reaction of carbon nitride (0.1158 g, 1.2 mmol) with hydrochloric acid (1 mmol) at 120 °C for 6 h to obtain a reaction solution; cool the reaction solution to room temperature, centrifuge it, wash it 5 times with ethanol and deionized water, and dry it at 80 °C for 12 hours to obtain carbon nitride nanosheets.
[0031] (2) Mix polyvinylpyrrolidone (20 mL), ethylene glycol (2 mL) and tetrahydrofuran (2 mL) to obtain a mixed solution; add the silicon-containing precursor (0.03 mol) and carbon nitride nanosheets (0.1158 g, 1.2 mmol) to the mixed solution, stir and mix for 3 h, then cast it on a petri dish with a diameter of 90 mm, and then age it at 120 °C for 36 h to obtain a uniform thin film.
[0032] (3) Under nitrogen atmosphere, the uniform film was heated at 400 °C for 7 h to obtain Au-loaded porous silica@carbon nitride.
[0033] (4) Under nitrogen atmosphere, Au-loaded porous silica@carbon nitride (0.03 mol) and reducing agent magnesium powder (0.729 g, 0.03 mol) were heated from room temperature of 25 °C to 700 °C at a heating rate of 0.5 °C / min and calcined for 6 h to obtain Au-loaded porous silicon@carbon nitride.
[0034] It can be seen from Figure 1 that at a current density of 1 A / g, the initial discharge specific capacity is 2468 mAh / g. After 100 cycles, the discharge specific capacity is 2248 mAh / g, and the capacity retention rate is 91.1%.
[0035] Example 2 A preparation method of an Au-loaded porous silicon@carbon nitride anode material includes the following steps: (1) Oxalic acid (0.9 g, 0.01 mol) was added to deionized water (30 mL), and the mixture was stirred and mixed at 80 °C for 1 h to obtain an oxalic acid aqueous solution; chloroauric acid (0.0466 g, 0.9 mmol) and tetraethyl orthosilicate (0.067 mL, 0.03 mol) were added to the oxalic acid aqueous solution, and the mixture was stirred and mixed at 80 °C for 2 h and then cooled to room temperature to obtain a silicon-containing precursor.
[0036] Melamine (1 g, 7.94 mmol) was calcined at 600 °C for 4 h and cooled to room temperature to obtain carbon nitride (0.3807 g, 3.96 mmol); carbon nitride (0.0579 g, 0.6 mmol) and hydrochloric acid (0.5 mmol) were subjected to hydrothermal reaction at 140 °C for 4 h to obtain a reaction solution; the reaction solution was cooled to room temperature, centrifuged, washed 5 times with ethanol and deionized water, and dried at 80 °C for 12 h to obtain carbon nitride nanosheets.
[0037] (2) Polyvinylpyrrolidone (24 mL), ethylene glycol (2 mL) and tetrahydrofuran (2 mL) were mixed to obtain a mixed solution; the silicon-containing precursor (0.03 mol) and carbon nitride nanosheets (0.6 mmol) were added to the mixed solution, stirred and mixed for 3 h, then cast on a petri dish with a diameter of 90 mm, and aged at 100 °C for 48 h to obtain a uniform film.
[0038] (3) Under argon atmosphere, the uniform film was heated at 500 °C for 5 h to obtain Au-loaded porous silica@carbon nitride.
[0039] (4) Under argon atmosphere, gold-loaded porous silica@carbon nitride (0.03 mol) and reducing agent aluminum powder (0.809 g, 0.03 mol) were heated from room temperature of 25 °C to 800 °C at a heating rate of 1.0 °C / min and calcined for 5 h to obtain gold-loaded porous silicon@carbon nitride.
[0040] It can be seen from Figure 2 that under the current density of 1 A / g, the initial discharge specific capacity is 2566 mAh / g. After 100 cycles, the discharge specific capacity is 2252 mAh / g, and the capacity retention rate is 87.8%.
[0041] Example 3 A preparation method of a gold-loaded porous silicon@carbon nitride anode material, comprising the following steps: (1) Oxalic acid (0.9 g, 0.01 mol) was added to deionized water (30 mL), and the mixture was stirred and mixed at 80 °C for 2 h to obtain an oxalic acid aqueous solution; fluoroauric acid (0.411 g, 1.5 mmol) and tetraethyl orthosilicate (0.067 mL, 0.03 mol) were added to the oxalic acid aqueous solution, and the mixture was stirred and mixed at 80 °C for 1 h and then cooled to room temperature to obtain a silicon-containing precursor.
[0042] Melamine (1 g, 7.94 mmol) was calcined at 600 °C for 4 h and cooled to room temperature to obtain carbon nitride (0.3807 g, 3.96 mmol); carbon nitride (0.166 g, 1.8 mmol) and hydrochloric acid (1.5 mmol) were subjected to hydrothermal reaction at 140 °C for 4 h to obtain a reaction solution; the reaction solution was cooled to room temperature, centrifuged, washed 5 times with ethanol and deionized water, and dried at 80 °C for 12 hours to obtain carbon nitride nanosheets.
[0043] (2) Polyvinylpyrrolidone (24 mL), ethylene glycol (2 mL) and tetrahydrofuran (2 mL) were mixed to obtain a mixed solution; the silicon-containing precursor (0.03 mol) and carbon nitride nanosheets (0.06 mmol) were added to the mixed solution, stirred and mixed for 3 h, then cast on a petri dish with a diameter of 90 mm, and aged at 100 °C for 42 h to obtain a uniform thin film.
[0044] (3) Under argon atmosphere, the uniform thin film was heated at 450 °C for 6 h to obtain gold-loaded porous silica@carbon nitride.
[0045] (4) Under argon atmosphere, gold-loaded porous silica@carbon nitride (0.03 mol) and reducing agent boron (0.324 g, 0.03 mol) were heated from room temperature of 25 °C to 850 °C at a heating rate of 0.5 °C / min and calcined for 4 h to obtain gold-loaded porous silicon@carbon nitride.
[0046] It can be seen from Figure 3It can be seen that at a current density of 1 A / g, the initial discharge specific capacity is 2575 mAh / g. After 100 cycles, the discharge specific capacity is 2230 mAh / g, and the capacity retention rate is 86.6%.
[0047] Comparative example Comparative example 1 A silicon negative electrode material, comprising the following steps: (1) Add oxalic acid (0.9 g, 0.01 mol) to deionized water (30 mL), stir and mix at 60 °C for 2 h to obtain an oxalic acid aqueous solution; add chloroauric acid (0.118 g, 0.3 mmol) and tetraethyl orthosilicate (0.067 mL, 0.03 mol) to the oxalic acid aqueous solution, stir and mix at 50 °C for 3 h, and then cool to room temperature to obtain a silicon-containing precursor.
[0048] Calcine melamine (1 g, 7.94 mmol) at 500 °C for 6 h, and cool to room temperature to obtain carbon nitride (0.3807 g, 3.96 mmol); carry out a hydrothermal reaction of carbon nitride (0.1158 g, 1.2 mmol) with hydrochloric acid (1 mmol) at 120 °C for 6 h to obtain a reaction solution; cool the reaction solution to room temperature, centrifuge it, wash it 5 times with ethanol and deionized water, and dry it at 80 °C for 12 hours to obtain carbon nitride nanosheets.
[0049] (2) Mix polyvinylpyrrolidone (20 mL), ethylene glycol (2 mL) and tetrahydrofuran (2 mL) to obtain a mixed solution; add the silicon-containing precursor (0.03 mol) and carbon nitride nanosheets (0.1158 g, 1.2 mmol) to the mixed solution, stir and mix for 4 h, then cast it on a petri dish with a diameter of 90 mm, and then age it at 90 °C for 60 h to obtain a uniform film.
[0050] (3) Under nitrogen conditions, heat the uniform film at 350 °C for 8 h to obtain gold-loaded porous silica@carbon nitride.
[0051] (4) Under nitrogen conditions, heat gold-loaded porous silica@carbon nitride (0.03 mol) and reducing agent magnesium powder (0.729 g, 0.03 mol) from room temperature of 25 °C to 700 °C at a heating rate of 0.5 °C / min and calcine for 6 h to obtain a silicon negative electrode material.
[0052] At a current density of 1 A / g, the initial discharge specific capacity is 2355 mAh / g. After 100 cycles, the discharge specific capacity is 1965 mAh / g, and the capacity retention rate is 83.44%.
[0053] Comparative example 2 A silicon negative electrode material, comprising the following steps: (1) Oxalic acid (0.9 g, 0.01 mol) was added to deionized water (30 mL), and the mixture was stirred at 60 °C for 2 h to obtain an oxalic acid aqueous solution. Chloroauric acid (0.118 g, 0.3 mmol) and tetraethyl orthosilicate (0.067 mL, 0.03 mol) were added to the oxalic acid aqueous solution, and the mixture was stirred at 80 °C for 1 h and then cooled to room temperature to obtain a silicon-containing precursor.
[0054] Melamine (1 g, 7.94 mmol) was calcined at 500 °C for 6 h and cooled to room temperature to obtain carbon nitride (0.3807 g, 3.96 mmol). Carbon nitride (0.1158 g, 1.2 mmol) and hydrochloric acid (1 mmol) were subjected to a hydrothermal reaction at 120 °C for 6 h to obtain a reaction solution. The reaction solution was cooled to room temperature, centrifuged, washed 5 times with ethanol and deionized water, and dried at 80 °C for 12 h to obtain carbon nitride nanosheets.
[0055] (2) Polyvinylpyrrolidone (20 mL), ethylene glycol (2 mL) and tetrahydrofuran (2 mL) were mixed to obtain a mixed solution. The silicon-containing precursor (0.03 mol) and carbon nitride nanosheets (0.1158 g, 1.2 mmol) were added to the mixed solution, stirred for 1 h, cast on a petri dish with a diameter of 90 mm, and then aged at 130 °C for 29 h to obtain a uniform film.
[0056] (3) Under nitrogen conditions, the uniform film was heated at 550 °C for 4 h to obtain Au-loaded porous silica@carbon nitride.
[0057] (4) Under nitrogen conditions, Au-loaded porous silica@carbon nitride (0.03 mol) and reducing agent magnesium powder (0.729 g, 0.03 mol) were heated from room temperature of 25 °C to 700 °C at a heating rate of 0.5 °C / min and calcined for 6 h to obtain a silicon negative electrode material.
[0058] At a current density of 1 A / g, the initial discharge specific capacity was 2310 mAh / g. After 100 cycles, the discharge specific capacity was 1902 mAh / g, and the capacity retention rate was 82.3%.
[0059] The initial discharge specific capacity, the discharge specific capacity after 100 cycles, and the capacity retention rate of the Au-loaded porous silicon@carbon nitride prepared in Examples 1-3 of this application and the silicon negative electrode materials prepared in Comparative Examples 1-2 are shown in the following table.
[0060] By analyzing the data in the above table, it can be seen that for the gold-loaded porous silicon@carbon nitride prepared in Examples 1 to 3, the initial discharge specific capacity is as high as 2468-2575 mAh / g, and after 100 cycles, the capacity retention rate is as high as 86.6-91.09%. This shows that the gold-loaded porous silicon@carbon nitride prepared in Examples 1 to 3 of this application has excellent conductivity and stability.
[0061] At the same time, compared with Comparative Examples 1 and 2, the initial discharge specific capacity of Example 1 is relatively increased by 4.80-6.84%, and after 100 cycles, the capacity retention rate is relatively increased by 14.40-18.19%. This shows that in the preparation method of the gold-loaded porous silicon@carbon nitride of this application, by controlling the process conditions of step (1), step (2) and step (3), the electrochemical performance of the finally prepared gold-loaded porous silicon@carbon nitride can be improved. The reason for this analysis may be that under the process conditions of this application, the distribution of gold on the silicon surface and the pore structure of the uniform thin film can be adjusted to obtain gold-loaded porous silica@carbon nitride with a high specific surface area, thereby improving the electrochemical performance of the gold-loaded porous silicon@carbon nitride.
[0062] This specific embodiment is only an interpretation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as they are within the scope of the claims of this application, they are protected by the patent law.
Claims
1. A preparation method of a gold-loaded porous silicon@carbon nitride anode material, characterized in that, It includes the following steps: (1) Mix chloroauric acid, organosilicon and oxalic acid aqueous solution, and stir and react at 60 - 80 °C for 1 - 2 h to obtain a silicon-containing precursor; (2) Mix the template agent and the solvent, add the silicon-containing precursor and carbon nitride nanosheets, first stir and mix for 2 - 3 h, then cast on a petri dish, and finally age at 100 - 120 °C for 36 - 48 h to obtain a uniform film; (3) Under an inert gas condition, heat the uniform film at 400 - 500 °C for 5 - 7 h to obtain gold-loaded porous silica@carbon nitride; (4) Under an inert atmosphere condition, heat gold-loaded porous silica@carbon nitride and a reducing agent from 20 - 25 °C to 700 - 850 °C at a heating rate of 0.5 - 1.0 °C / min and calcine for 4 - 6 h to obtain gold-loaded porous silicon@carbon nitride.
2. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 1, characterized in that, In the step (1), the molar ratio of chloroauric acid to organosilicon is (0.01 - 0.05):
3.
3. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 1, characterized in that, In the step (1), the chloroauric acid is one or more of chloroauric acid, fluoroauric acid and bromoauric acid.
4. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 1, characterized in that, In the step (1), the organosilicon is one or two of tetraethyl orthosilicate and tetrabutyl orthosilicate.
5. The preparation method of the gold-loaded porous silicon@carbon nitride negative electrode material according to claim 1, characterized in that, In the step (1), the preparation method of the carbon nitride nanosheets is: calcine melamine at 500 - 600 °C for 4 - 6 h, cool to obtain carbon nitride; mix the carbon nitride and hydrochloric acid, and carry out hydrothermal reaction at 120 - 140 °C for 4 - 6 h to obtain carbon nitride nanosheets.
6. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 1, characterized in that In the step (2), the template agent is polyvinylpyrrolidone, and the solvent is ethylene glycol and tetrahydrofuran.
7. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 6, wherein, In the step (2), the molar ratio of the silicon-containing precursor to the carbon nitride nanosheets is 30:(0.6 - 2); the volume ratio of polyvinylpyrrolidone, ethylene glycol and tetrahydrofuran is (10 - 12):1:
1.
8. The preparation method of the gold-loaded porous silicon@carbon nitride anode material according to claim 1, characterized in that, In the step (4), the reducing agent is one or more of magnesium powder, aluminum powder and boron.
9. A gold-loaded porous silicon@carbon nitride anode material is prepared by the preparation method of the gold-loaded porous silicon@carbon nitride anode material according to any one of claims 1 - 8.
10. Application of a gold-loaded porous silicon@carbon nitride anode material in a lithium battery anode.