Lithium / sodium ion battery negative electrode carbon material and preparation method thereof
By using a self-assembly method with boric acid and nitrogen-containing water-soluble compounds, a carbon material for lithium/sodium-ion battery anodes with a pyridine NB and a nano-sandwich structure was prepared, solving the problems of low capacity and slow kinetics, and achieving efficient material preparation and performance improvement.
Patent Information
- Application Number
- CN202311505299.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-13
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2043-11-13
AI Technical Summary
Existing lithium-ion battery anode carbon materials suffer from low capacity and slow kinetics, and conventional processes for preparing nitrogen-doped carbon materials are complex and costly.
Using boric acid as the boron source template, biomass raw materials as the carbon source, and nitrogen-containing water-soluble compounds as the nitrogen source, carbon materials with pyridine NB and nano sandwich structures were prepared by ordered self-assembly through rapid water bath evaporation.
It effectively solves the aggregation problem of two-dimensional materials, improves the electrochemical performance of materials, and the preparation process is safe, environmentally friendly, simple, and low in cost.
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Figure CN117658100B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery electrode material technology, specifically relating to a carbon material for the negative electrode of a lithium / sodium-ion battery and its preparation method. Background Technology
[0002] With the development of science and technology, people have placed higher demands on new energy storage devices. Therefore, exploring new energy storage devices with higher energy density, power density, and ultra-long cycle life is of great significance. As two typical energy storage systems, lithium-ion batteries (LIBs) and supercapacitors (SCs) exhibit complementary characteristics and have been widely used in our daily lives. Lithium-ion batteries (LIBs) have high capacity but suffer from low power density and short cycle life, while supercapacitors (SCs) have high power density and long cycle life, but suffer from low energy density. This difference is due to the different energy storage mechanisms of these two types of energy storage devices. Therefore, to address this issue, lithium-ion capacitors (LICs) with a battery-type anode and a capacitor-type cathode have been proposed.
[0003] Electrode materials are a key factor affecting the electrochemical performance of lithium-ion capacitors. Currently, carbon materials are the most widely used electrode materials in the market due to their advantages such as large specific surface area, stable physicochemical properties, low cost, and abundant natural reserves. However, carbon materials suffer from low capacity and slow kinetics. Heteroelement doping and rational structural design are effective methods to address these problems. Nitrogen, as a heteroatom, can effectively improve the capacity and physicochemical properties of the material. Nitrogen doping exists in three main forms: pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen. Among them, pyridine nitrogen, as a nitrogen configuration, has the highest theoretical specific capacity. Two-dimensional carbon materials have good continuity, which can reduce contact resistance between materials. Compared with three-dimensional porous carbon, two-dimensional carbon materials do not have the charge diffusion resistance caused by deep pore structures, and their open structure allows for sufficient contact with the electrolyte. However, two-dimensional carbon materials can agglomerate during the preparation process. To solve this problem, people often add carbon nanoparticles, carbon nanotubes, etc. to the two-dimensional carbon materials or prepare sandwich structure materials through templates. However, conventionally prepared nitrogen-doped carbon materials have complex nitrogen configurations, and the process for preparing nitrogen with a single configuration is complicated and costly. Summary of the Invention
[0004] To address the aforementioned problems in existing technologies, the technical problem this invention aims to solve is to provide a method for preparing a lithium / sodium-ion battery anode carbon material. This method uses boric acid as a boron source template, biomass raw materials as a carbon source, and adds a nitrogen-containing water-soluble compound as a nitrogen source. Ordered self-assembly is achieved through rapid water bath evaporation, followed by a one-step preparation process under the confinement effect of the template formed by excess boric acid and the nitrogen source. Another technical problem this invention aims to solve is to provide a lithium / sodium-ion battery anode carbon material with a pyridine (NB) and nano-sandwich structure, exhibiting excellent electrochemical performance.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing a negative electrode carbon material for lithium / sodium-ion batteries involves dissolving water-soluble biomass raw materials, boric acid, and nitrogen-containing water-soluble compounds in water, inducing ordered self-assembly through rapid evaporation via water bath heating, drying the sample in an oven after the water has evaporated, carbonizing the dried sample in a tube furnace under a nitrogen atmosphere, naturally cooling to room temperature after carbonization, and then washing the obtained sample with water and ethanol to remove impurities and excess boric acid until the sample is neutral, and drying to obtain a carbon material rich in pyridine (NB) and a nano-sandwich structure.
[0007] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery involves a boric acid to nitrogen-containing water-soluble compound mass ratio of 16:1 to 4:1 and a boric acid to water-soluble biomass raw material mass ratio of 8:1 to 4:1. Boric acid is dissolved in water before the nitrogen-containing water-soluble compound and water-soluble biomass raw material are added. Preferably, the mass ratio of boric acid to nitrogen-containing water-soluble compound mass ratio is 8:1.5 and the mass ratio of boric acid to water-soluble biomass raw material mass ratio is 8:1.
[0008] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery involves heating in a water bath at a temperature of 60–90°C until no obvious liquid remains; preferably, the temperature for rapid evaporation in the water bath is 80°C.
[0009] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery involves drying the sample after rapid evaporation in a water bath in an oven at 80°C for 12-24 hours.
[0010] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery involves heating the dried sample to a pretreatment temperature of 600-900℃ at a heating rate of 2-10℃ / min and holding it at that temperature for 60-120min, and then carbonizing it under the confinement of a template; preferably, the carbonization temperature is 900℃.
[0011] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery involves washing the activated material with water at 50-100°C until the pH reaches 6-7, washing it with ethanol 1-2 times, and then drying it in an oven at 80°C for 5 hours.
[0012] The method for preparing the negative electrode carbon material of the lithium / sodium ion battery uses either sodium lignosulfonate or calcium lignosulfonate as the biomass raw material and either urea or ammonia water as the nitrogen source.
[0013] The carbon material for the negative electrode of lithium / sodium ion batteries prepared by the above method.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0015] (1) Using excess boric acid and nitrogen-containing water-soluble compounds to form templates for boron and nitrogen sources, pyridine NB-doped nano sandwich structures are prepared by rapid evaporation in a water bath, self-assembly, and confinement. The production process is safe, environmentally friendly, and pollution-free, and the preparation method is simple and the subsequent processing is simple.
[0016] (2) It effectively solves the agglomeration phenomenon that occurs during the preparation of two-dimensional materials, and the formed pyridine NB and nano sandwich structure effectively improves the electrochemical performance of the material. Attached Figure Description
[0017] Figure 1 These are scanning electron microscope (SEM) images of the materials obtained in Example 1(d) and Comparative Examples 1(a), 2(b), and 3(c);
[0018] Figure 2 XPS total spectrum of materials obtained in Example 1 and Comparative Examples 1, 2, and 3 (a) and XPS peaks of various types of nitrogen in activated carbon obtained in Example 1 (b), Comparative Example 1 (c), and 2 (d);
[0019] Figure 3 The graphs show the electrochemical performance of the materials obtained in Example 1 and Comparative Examples 1, 2, and 3. Detailed Implementation
[0020] The present invention will be further described below with reference to specific embodiments.
[0021] Comparative Example 1
[0022] 8g of boric acid was dissolved in 50ml of deionized water, then 1g of sodium lignosulfonate and 1.5g of urea were added. After stirring evenly, the mixture was placed in a freeze dryer at -40℃ for freeze drying. The dried sample was then placed in an oven at 80℃ for 12h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral. The sample was then dried at 80℃ for 5h.
[0023] Comparative Example 2
[0024] 8g of boric acid was dissolved in 50ml of deionized water, and then 1g of sodium lignosulfonate was added. After stirring evenly, the mixture was placed in a water bath at 90℃ for rapid evaporation. The dried sample was then placed in an oven at 80℃ for 12h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0025] Comparative Example 3
[0026] 1g of sodium lignosulfonate was dissolved in deionized water, and then 1.5g of urea was added. After stirring evenly, the mixture was placed in a water bath at 90℃ for rapid evaporation. The dried sample was then placed in an oven at 80℃ for 12 hours. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral. The sample was then dried at 80℃ for 5 hours.
[0027] Example 1
[0028] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0029] 8g of boric acid was dissolved in 50ml of deionized water, then 2g of urea and 1g of sodium lignosulfonate were added, stirred evenly, and then placed in a water bath at 90℃ for rapid evaporation. The evaporated sample was then placed in an oven and dried at 80℃ for 12h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 100 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0030] Example 2
[0031] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0032] 8g of boric acid was dissolved in 50ml of deionized water, then 1.5g of urea and 1g of sodium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 12h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0033] Example 3
[0034] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0035] 8g of boric acid was dissolved in 50ml of deionized water, then 1g of urea and 1g of sodium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 24h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0036] Example 4
[0037] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0038] 8g of boric acid was dissolved in 50ml of deionized water, then 1.5g of urea and 1g of sodium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 24h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 10℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0039] Example 5
[0040] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0041] 8g of boric acid was dissolved in 50ml of deionized water, then 1.5g of urea and 2g of sodium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 24h. The dried sample was then placed in a tube furnace and heated to 900℃ at a rate of 2℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 120 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0042] Example 6
[0043] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0044] 8g of boric acid was dissolved in 50ml of deionized water, then 1.5g of urea and 1g of sodium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 24h. The dried sample was then placed in a tube furnace and heated to 800℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 60 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0045] Example 7
[0046] A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, specifically comprising:
[0047] 8g of boric acid was dissolved in 50ml of deionized water, then 1.5g of urea and 1g of calcium lignosulfonate were added. After stirring evenly, the mixture was placed in a water bath at 80℃ for rapid evaporation. The evaporated sample was then placed in an oven at 80℃ for 24h. The dried sample was then placed in a tube furnace and heated to 700℃ at a rate of 5℃ / min under nitrogen gas (nitrogen flow rate of 150 ml / min). The temperature was maintained at this temperature for 60 minutes. After cooling to room temperature, the activated material was washed with water at 100℃ until the pH was neutral, and then dried at 80℃ for 5h.
[0048] The morphology and surface properties of the samples prepared in Comparative Examples 1-3 and Example 1 were tested, and the test results are as follows: Figure 1 As shown. By Figure 1 As shown in (a) and 1(d), Comparative Example 1 and Example 1 were prepared by freeze-drying and rapid evaporation, respectively, followed by carbonization. Comparative Example 1 exhibited an irregular blocky structure, while Example 1 exhibited a sandwich structure, indicating that rapid evaporation played an important role in the structure formation process. Comparative Example 2 ( Figure 1(d) is a carbon material prepared by rapid evaporation and carbonization after dissolving boric acid and sodium lignosulfonate. Comparative Example 2 exhibits a layered structure, indicating that boric acid serves as a template for forming the layered structure. Comparative Example 3 ( Figure 1 (c) is a carbon material prepared by rapidly evaporating and carbonizing urea and sodium lignosulfonate after dissolving them. Comparative Example 3 shows an irregular granular structure. The carbon material obtained by rapidly evaporating sodium lignosulfonate, boric acid, and urea shows a nano-sandwich structure in which boric acid and urea are both essential.
[0049] Figure 2 (a) XPS spectra of the carbon materials obtained in Example 1 and Comparative Examples 1, 2, and 3. In Comparative Example 2, the boron content in the layered carbon material prepared by boric acid and sodium lignosulfonate was only 1.5%, with boric acid mainly acting as a template to regulate morphology. In Comparative Example 3, the nitrogen content in the carbon material prepared by urea and sodium lignosulfonate was only 2.99%, and the morphology of the prepared carbon material was irregular. In Comparative Example 1 and Example 1, both boron and nitrogen contents were significantly increased, indicating that boron-nitrogen co-doping can mutually promote the increase in doping amount.
[0050] Figure 2 (b), 2(c), and 2(d) are XPS peaks of various types of nitrogen in the activated carbon obtained in Example 1, Comparative Example 1, and Comparative Example 2. In Example 1 and Comparative Example 1, the nitrogen configuration is mainly pyridine N, while in Example 2, the nitrogen configuration is more complex. Excess boric acid on the surface can facilitate the transformation of nitrogen configuration into pyridine N.
[0051] Figure 3 For the half-cell performance testing of the carbon materials obtained in Example 1 and Comparative Examples 1, 2, and 3, the prepared carbon materials were mixed with binder and acetylene black in a ratio of 8:1:1 and coated onto copper foil. After drying, the mixture was cut into discs to be used as negative electrodes. Then, it was assembled with lithium sheets in a glove box to form a half-cell for testing. The test was conducted using a Blue Electric electrochemical workstation with a voltage window of 0–3V. Figure 3 The specific capacity of the carbon material prepared in Example 1 is higher than that of Comparative Examples 1, 2 and 3.
Claims
1. A method for preparing a carbon material for the negative electrode of a lithium / sodium ion battery, characterized in that, Water-soluble biomass raw materials, boric acid, and nitrogen-containing water-soluble compounds are dissolved in water. Self-assembly is induced by rapid evaporation through a water bath. After complete evaporation, the mixture is dried and then carbonized at 600-900℃. After carbonization, the mixture is washed until neutral and dried to obtain pyridine NB and nano-sandwich structured carbon materials. The water-soluble biomass raw material is either sodium lignosulfonate or calcium lignosulfonate. The mass ratio of boric acid to nitrogen-containing water-soluble compounds is 16:1 to 4:1, and the mass ratio of boric acid to water-soluble biomass raw materials is 8:1 to 4:
1. Boric acid is dissolved in deionized water, and then the nitrogen-containing water-soluble compounds and water-soluble biomass raw materials are added. The water bath heating temperature is 60-90℃. The nitrogen-containing water-soluble compounds are either urea or ammonia water.
2. The method for preparing the lithium / sodium ion battery negative electrode carbon material according to claim 1, characterized in that, After water bath drying, the samples were dried in an oven at 80℃ for 12-24 hours.
3. The method for preparing the lithium / sodium ion battery negative electrode carbon material according to claim 1, characterized in that, The carbonization process specifically involves heating the dried sample to the carbonization temperature at a heating rate of 2~10℃ / min and holding it at that temperature for 60~120min, carbonizing it under the confinement of the template.
4. The method for preparing the lithium / sodium ion battery negative electrode carbon material according to claim 1, characterized in that, After carbon activation, the activated material is washed with water at 50~100 ℃ until the pH is 6~7, then washed with ethanol, and then dried at 80 ℃ for 12h.
5. The lithium / sodium ion battery anode carbon material prepared by the method described in any one of claims 1 to 4.