Biomass-derived n / o co-doped carbon aerogel negative electrode material for sodium-ion batteries and preparation method thereof

Abstract

The application provides a biomass-derived N / O co-doped carbon aerogel negative electrode material for sodium ion batteries and a preparation method thereof. ‑1 The sodium ion battery assembled by using the carbon aerogel material as a negative electrode active material has a high reversible specific capacity and a good rate performance, a first discharge capacity is as high as 625 mAh g ‑1 at a current density of 50 mA g ‑1 , and the reversible capacity is still maintained at 361 mAh g ‑1 after 50 cycles, and has excellent electrochemical performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sodium ion batteries, in particular to a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material and a preparation method thereof. BACKGROUND

[0002] Large-scale application of renewable energy cannot be separated from a high-efficiency and safe energy storage system. Due to the high energy density, low cost, lightness and other characteristics, the rechargeable ion battery is a potential choice for the large-scale energy storage system. In addition to the currently booming lithium ion battery, the sodium ion battery has been listed as an advanced battery technology for 2030 in China and Europe. Compared with the low reserves and difficult mining of lithium resources, the abundant sodium resources on the earth make the sodium ion battery have unique competitiveness in low-cost energy storage.

[0003] Although the metal sodium itself has a high theoretical capacity of 1165 mAh g -1 , the instability of the sodium negative electrode and the electrolyte interface and the sodium dendrite growth make the sodium metal negative electrode have low energy efficiency and be unsafe in actual application. Similar to the graphite negative electrode of the lithium ion battery, the negative electrode side of the sodium ion battery needs to have a sodium ion host with a stable low potential charge and discharge platform. Due to the large size of the sodium ion, the graphite negative electrode suitable for lithium ion intercalation cannot accommodate the sodium ion, and the hard carbon with a larger interlayer spacing is one of the most promising negative electrode materials for the sodium ion battery. In 2000, Dahn et al. first proposed that the hard carbon is used as the negative electrode material of the sodium ion battery in High capacity anode materials for rechargeable sodium-ion batteries.

[0004] As a member of the hard carbon family, the carbon aerogel has the characteristics of ultra-low density, large surface area, high conductivity, thermal and chemical stability, good mechanical properties and the like, and can be used as a negative electrode material of a sodium ion battery. According to the different carbon precursors used, the carbon aerogel can be divided into phenolic resin-derived aerogels, other carbon allotrope-derived carbon aerogels and biomass-derived carbon aerogels. The biomass-derived carbon aerogel mainly uses biomass (such as ginkgo leaves, cattail, corn straw, reed straw, camphor tree bark, sugarcane residue and the like) as a precursor, and has unique characteristics such as abundant source, environmental friendliness and considerable economic value.

[0005] However, the biomass-derived carbon aerogel has not been used as a negative electrode material of a sodium ion battery at present, therefore, the application combines the sodium storage mechanism in the hard carbon and researches a biomass-derived N / O co-doped carbon aerogel negative electrode material of a sodium ion battery. SUMMARY

[0006] The application aims to provide a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material and a preparation method thereof.

[0007] According to a first aspect of the application, a preparation method of a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material is provided, which comprises the following steps:

[0008] S1, transferring the biomass precursor after treatment to a hydrothermal reactor for heat treatment to obtain a biomass hydrogel;

[0009] S2, soaking the biomass hydrogel obtained in step S1 in hot water to remove soluble impurities, and then freeze-drying to obtain a biomass aerogel;

[0010] S3, heating the biomass aerogel obtained in step S2 to a desired temperature under an inert atmosphere and keeping the temperature, to obtain a carbon aerogel;

[0011] S4, ultrasonic dispersing the carbon aerogel obtained in step S4 in a mixed solvent composed of deionized water and diethylene triamine, adding ammonium molybdate, stirring to obtain a suspension, transferring the suspension to a hydrothermal reactor for reaction, cooling after the reaction, washing and drying the cooled product, and heat treating the obtained solid powder in a nitrogen atmosphere to obtain an N / O co-doped carbon aerogel sodium ion battery negative electrode material.

[0012] As an optional embodiment, the biomass precursor is one or more of sugarcane, grapefruit peel, durian shell, and wax gourd.

[0013] As an optional embodiment, in step S1, the heat treatment temperature is 160-200℃, and the treatment time is 1h-48h.

[0014] As an optional embodiment, in step S2, the hot water soaking temperature is 60-80℃, and the soaking time is 10h-48h.

[0015] As an optional embodiment, in step S2, the freeze-drying temperature is -48℃ to -80℃, and the freeze-drying time is 1-5 days.

[0016] As an optional embodiment, in step S3, the temperature is raised to 600-1200℃ at a temperature raising rate of 1° / min-5° / min, and the temperature is kept for 1h-2h to obtain a carbon aerogel.

[0017] As an optional implementation, in the step S4, the mass ratio of the carbon aerogel and the ammonium molybdate in the suspension is 1:(10-20), and the volume ratio of the deionized water and the diethylene triamine is 9:5.

[0018] As an optional implementation, in the step S4, the treatment condition of the suspension in the hydrothermal reactor is that the temperature is kept at 160-200 ℃ for 12-48 h.

[0019] As an optional implementation, in the step S4, the process of the heat treatment of the solid powder in the nitrogen atmosphere is that the temperature is raised to 600-1000 ℃ at a temperature raising rate of 1-3 ° / min, and the temperature is kept for 1-3 h.

[0020] According to a second aspect of the object of the present application, a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material is provided, which is prepared by the above method.

[0021] As can be seen from the technical solutions of the present application, the biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material is prepared by using biomass as raw material and doping heteroatoms in the carbon-based material, and the interlayer spacing of the obtained carbon aerogel material is higher than the critical interlayer spacing of the intercalation hard carbon layer. + The critical interlayer spacing of the intercalation hard carbon layer has a high electrochemical active site, improves the electrical conductivity, and has a high specific surface area and pore volume, which is beneficial to the infiltration of the electrolyte and the rapid transmission of the ions, so that the sodium ion battery assembled by using the carbon aerogel material as the negative active material is beneficial to the embedding and de-embedding of Na + , and has a high reversible specific capacity and a good rate performance, and can be used as a sodium ion battery negative electrode material.

[0022] The preparation method of the present application uses biomass as raw material, has the characteristics of wide raw material source and low cost, and has the characteristics of simple preparation process, easy operation and easy industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the X-ray diffraction pattern of the sample of Example 1 of the present application.

[0024] Figure 2 is the field emission scanning electron microscope image (a, b, c, d) and the corresponding energy spectrum element mapping image (e, f, g) of the sample of Example 1 of the present application.

[0025] Figure 3 is the X-ray photoelectron spectrogram of the sample of Example 1 of the present application; wherein a is the full spectrum; b is the C1s fine spectrum; c is the O1s fine spectrum; d is the N1s fine spectrum.

[0026] Figure 4is the nitrogen adsorption-desorption curve (a) and the corresponding pore size distribution graph (b) of the sample of embodiment 1 of the present application.

[0027] Figure 5 is the cycle stability curve of the sample of embodiment 1 of the present application and the sample of the comparative example, wherein the abscissa is the discharge capacity (mAh g -1 ), the ordinate is the cycle number (n), and the current density is 50 mA g -1 .

[0028] Figure 6 is the rate performance curve of the sample of embodiment 1 of the present application and the sample of the comparative example, wherein the abscissa is the discharge capacity (mAh g -1 ), the ordinate is the cycle number (n), and the current density is 25, 50, 100, 200, 500, 1000 mA g -1 . DETAILED DESCRIPTION

[0029] In order to better understand the technical content of the present application, specific embodiments are described below with reference to the accompanying drawings.

[0030] Aspects of the present application are described in the disclosure by reference to the accompanying drawings, which show many illustrative embodiments. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present application. It should be understood that the various concepts and embodiments introduced above, and those described in more detail below, can be implemented in any of numerous ways.

[0031] Through the study of sodium storage mechanism in hard carbon material, it is known that hard carbon material has several different ion storage sites, including (1) intercalation between graphene sheets; (2) storage in closed micropores; (3) surface and defect adsorption.

[0032] Based on this, the present application aims to design a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material, and to construct a preparation method of a biomass-derived carbon aerogel material for sodium ion battery negative electrode. The prepared biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material has a large interlayer spacing, abundant defect sites and pore structure, can be used for sodium ion battery negative electrode material, and has excellent electrochemical performance.

[0033] In an exemplary embodiment of the present application, a preparation method of a biomass-derived N / O co-doped carbon aerogel sodium ion battery negative electrode material is provided, comprising the following steps:

[0034] Step 1, the biomass precursor bought from the market is treated and cut into blocks of appropriate size, and the blocky biomass precursor is transferred to a hydrothermal reactor for hydrothermal treatment.

[0035] Step 2, the biomass hydrogel obtained in step 1 is soaked in hot water at a certain temperature for a certain time to remove some soluble impurities.

[0036] Step 3, the biomass hydrogel obtained in step 2 is further freeze-dried at a certain temperature for several days to obtain a biomass aerogel.

[0037] Step 4, the biomass aerogel obtained in step 3 is heated to a certain temperature at a certain heating rate in an inert atmosphere, and the temperature is kept constant to obtain a carbon aerogel.

[0038] Step 5, the carbon aerogel obtained in step 4 is ultrasonically dispersed in a mixed solvent composed of deionized water and diethylene triamine, a certain amount of ammonium molybdate is added, after stirring for 10 min, the obtained suspension is transferred to a hydrothermal reactor for reaction, after cooling, washed with anhydrous ethanol and deionized water several times, then dried in a vacuum drying oven, the dried solid powder is heat treated in an inert atmosphere to obtain an N / O co-doped carbon aerogel material.

[0039] As an optional embodiment, the biomass precursor is one or more of a mixture of sugarcane, pomelo peel, durian shell, and wax gourd.

[0040] As an optional embodiment, in the aforementioned step 1, the heat treatment temperature is 160-200°C, and is particularly preferably 180°C; the treatment time is 1-48h.

[0041] As an optional embodiment, in the aforementioned step 2, the hot water soaking temperature is 60-80°C, and the soaking time is 10-48h.

[0042] As an optional embodiment, in the aforementioned step 3, the freeze-drying temperature is -48 to -80°C, and the freeze-drying time is 1-5 days.

[0043] As an optional embodiment, in the aforementioned step 4, the temperature is raised to 600-1200°C at a heating rate of 1-5°C / min, and the temperature is kept constant for 1-2h to obtain a carbon aerogel.

[0044] As an optional embodiment, in the aforementioned step 4, the inert atmosphere is one of argon, nitrogen, and helium.

[0045] As an optional embodiment, in the aforementioned step 5, in the suspension, the mass ratio of carbon aerogel to ammonium molybdate is 1:(10-20), and the volume ratio of deionized water to diethylene triamine is 9:5.

[0046] As an optional embodiment, in the aforementioned step 5, the treatment conditions of the suspension in the hydrothermal reactor are as follows: the temperature is kept constant at 160-200°C for 12-48h, and is particularly preferably kept constant at 200°C for 24h.

[0047] As an optional embodiment, in the aforementioned step 5, the process of heat treatment of the solid powder in a nitrogen atmosphere is as follows: heating to 600-1000℃ at a heating rate of 1-3° / min, and maintaining the temperature for 1-3h; and more preferably, heating to 850℃ at a heating rate of 2° / min, and maintaining the temperature for 2h.

[0048] In another exemplary embodiment of the present application, a biomass-derived N / O co-doped carbon aerogel negative electrode material for sodium ion batteries is also provided, which is prepared by the aforementioned method. When assembled into a sodium ion battery, the N / O co-doped carbon aerogel electrode has a first discharge capacity of up to 625mAh g-1 at a current density of 50mA g-1, and a reversible capacity of 361mAh g-1 after 50 cycles, showing excellent electrochemical performance. -1 -1 -1

[0049] For better understanding, the present application is further described below in conjunction with several specific examples, but the preparation process is not limited thereto, and the content of the present application is not limited thereto.

[0050] Unless otherwise specified, the materials in the examples are prepared according to existing methods, or directly purchased from the market.

[0051] Example 1

[0052] Sugarcane purchased from the market is treated and cut into appropriate size blocks, and the blocky sugarcane is transferred to a hydrothermal reactor, and treated at 180℃ for 12h. The obtained biomass hydrogel is soaked in hot water at 80℃ for 10h to remove some soluble impurities, and then frozen at -56℃ for 5 days to obtain a sugarcane aerogel. The sugarcane aerogel is heated to 1200℃ at a heating rate of 5℃ / min under a nitrogen atmosphere, and maintained at 1200℃ for 2h to obtain a carbon aerogel. -1

[0053] 0.1g of the carbon aerogel is ultrasonically dispersed in a mixed solvent composed of 45mL of deionized water and 25mL of diethylene triamine, and 1g of ammonium molybdate is added. After stirring for 10min, the obtained suspension is transferred to a hydrothermal reactor, and maintained at 200℃ for 24h. After cooling, the solid powder is dried in a vacuum drying oven, and then heated to 850℃ at a heating rate of 2℃ / min under an inert atmosphere, and maintained at 850℃ for 2h to obtain an N / O co-doped carbon aerogel material. -1

[0054] Example 2

[0055] ​​​​​The market-purchased pomelo peel was treated and cut into appropriate size pieces. The piece-shaped pomelo peel was transferred into a hydrothermal reactor, and hydrothermally treated at 180 °C for 48 h. The obtained biomass hydrogel was soaked in hot water at 60 °C for 48 h to remove some soluble impurities. The pomelo peel aerogel was obtained by freeze-drying at -56 °C for 3 days. The pomelo peel aerogel was dried in an inert atmosphere at 2 °C / min -1 Heating to 1000 °C and keeping for 1 h, the carbon aerogel was obtained.

[0056] 0.1 g of the carbon aerogel was ultrasonically dispersed in a mixed solvent composed of 45 mL of deionized water and 25 mL of diethylene triamine, 1 g of ammonium molybdate was added, and after stirring for 10 min, the obtained suspension was transferred into a hydrothermal reactor, and kept at 200 °C for 24 h. After cooling, it was washed several times with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven. The dried solid powder was dried in an inert atmosphere at 2 °C / min -1 Heating to 850 °C and keeping for 2 h, the N / O co-doped carbon aerogel material was obtained.

[0057] Example 3

[0058] The market-purchased durian shell was treated and cut into appropriate size pieces. The piece-shaped durian shell was transferred into a hydrothermal reactor, and hydrothermally treated at 180 °C for 1 h. The obtained biomass hydrogel was soaked in hot water at 60 °C for 48 h to remove some soluble impurities. The durian shell aerogel was obtained by freeze-drying at -80 °C for 1 day. The durian shell aerogel was dried in an inert atmosphere at 1 °C / min -1 Heating to 600 °C and keeping for 2 h, the carbon aerogel was obtained.

[0059] 0.1 g of the carbon aerogel was ultrasonically dispersed in a mixed solvent composed of 45 mL of deionized water and 25 mL of diethylene triamine, 1 g of ammonium molybdate was added, and after stirring for 10 min, the obtained suspension was transferred into a hydrothermal reactor, and kept at 200 °C for 24 h. After cooling, it was washed several times with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven. The dried solid powder was dried in an inert atmosphere at 2 °C / min -1 Heating to 850 °C and keeping for 2 h, the N / O co-doped carbon aerogel material was obtained.

[0060] Example 4

[0061] The market-purchased wax gourd was treated and cut into appropriate size pieces. The piece-shaped wax gourd was transferred into a hydrothermal reactor, and hydrothermally treated at 180 °C for 12 h. The obtained biomass hydrogel was soaked in hot water at 70 °C for 24 h to remove some soluble impurities. The wax gourd aerogel was obtained by freeze-drying at -48 °C for 5 days. The wax gourd aerogel was dried in an inert atmosphere at 2 °C / min -1Heating to 800℃ and holding for 1 hour yields carbon aerogel.

[0062] 0.1 g of carbon aerogel was ultrasonically dispersed in a mixed solvent consisting of 45 mL of deionized water and 25 mL of diethylenetriamine. 2 g of ammonium molybdate was added, and the mixture was stirred for 10 min. The resulting suspension was transferred to a hydrothermal reactor and kept at 200 °C for 24 h. After cooling, the suspension was washed several times with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven. The dried solid powder was then subjected to an inert atmosphere at 2 °C for [time missing]. -1 The temperature was raised to 850℃ and held for 2 hours to obtain N / O co-doped carbon aerogel material.

[0063] Comparative Example

[0064] Sugarcane purchased from the market was processed and cut into appropriately sized pieces. The sugarcane pieces were transferred to a hydrothermal reactor and hydrothermally treated at 180℃ for 12 hours. The resulting biomass hydrogel was then soaked in 80℃ hot water for 10 hours to remove some soluble impurities. The hydrogel was then freeze-dried at -56℃ for 5 days to obtain sugarcane aerogel. The sugarcane aerogel was then subjected to nitrogen atmosphere for 5 minutes. -1 Heating to 1200℃ and holding for 2 hours yields carbon aerogel.

[0065] The following is in conjunction with the appendix Figures 1-5 As shown, the performance test results of the N / O co-doped carbon aerogel material prepared in Example 1 are further explained.

[0066] XRD

[0067] like Figure 1 As shown, two significant broad peaks were observed in the N / O co-doped carbon aerogel at approximately 23° and 43°, corresponding to the (002) diffraction peak and (101) diffraction peak of the graphite structure, respectively. These relatively broad diffraction peaks indicate that the N / O co-doped carbon aerogel has a low degree of graphitization. Based on the Bragg equation, the interlayer spacing d of the (002) crystal planes of the N / O co-doped carbon aerogel is 0.39 nm, exceeding the critical insertion size of sodium ions at 0.37 nm.

[0068] Field emission scanning electron microscope images and corresponding energy dispersive elemental mapping images

[0069] like Figure 2 As shown in a and 2b, the N / O co-doped carbon aerogel has a network structure with a pore size of approximately 1 μm; further magnification reveals... Figure 2 As can be seen from c and 2d, the N / O co-doped carbon aerogel also contains a large number of mesopores.

[0070] Through the corresponding energy spectrum element mapping image ( Figure 2e-2g) It can be found that N and O elements are uniformly distributed on the carbon aerogel.

[0071] X-ray photoelectron spectroscopy

[0072] The surface composition and element chemical state of the N / O co-doped carbon aerogel were studied by X-ray photoelectron spectroscopy.

[0073] From Figure 3 a) It can be seen that the N / O co-doped carbon aerogel is composed of C, O and N elements, and the atomic percentage contents thereof are 88.65%, 9.24% and 2.11%, respectively.

[0074] As Figure 3 b) shows that the C1s spectrum of the N / O co-doped carbon aerogel can be divided into four individual component peaks, which correspond to C-C at 284.5 eV, C-N at 285.5 eV, COOH at 288.8 eV and O=C-O at 290.6 eV, respectively.

[0075] Figure 3 c) shows the O1s spectrum of the N / O co-doped carbon aerogel, which has three fitted peaks, corresponding to O-I (C=O, 530.5 eV), O-II (C-OH / C-O-C, 531.2 eV) and O-III (COOH, 534.2 eV), respectively.

[0076] As Figure 3 d) shows that the N1s spectrum of the sample shows three peaks at 398.2 (N-6), 400.1 (N-5) and 402.25 eV (N-Q), which can be attributed to pyridinic nitrogen, pyrrolic nitrogen and graphitic nitrogen, respectively.

[0077] Specific surface area and pore volume

[0078] Figure 4 a) is the adsorption-desorption curve of the N / O co-doped carbon aerogel, and the specific surface area and pore volume of the N / O co-doped carbon aerogel are calculated to be 410 m 2 g -1 and 0.23 cm 3 g -1 , respectively.

[0079] Figure 4 b) is the pore size distribution graph of the N / O co-doped carbon aerogel, and it can be seen that the sample has rich pore structure at 0-10 nm.

[0080] It can be proved from the above tests that the biomass-derived N / O co-doped carbon aerogel negative electrode material for sodium ion batteries is successfully prepared, and the material has a larger interlayer spacing, more electrochemically active sites, and a higher specific surface area and pore volume.

[0081] Electrochemical performance testing

[0082] The material of Example 1 (N / O co-doped carbon aerogel) and the comparative example (carbon aerogel) were tested for electrochemical performance, which was determined according to the following method:

[0083] Firstly, 0.1 g of PVDF was dissolved in NMP, then 0.7 g of carbon aerogel material (material of Example 1 or Comparative Example 1) and 0.2 g of conductive additive carbon black were added to the solution after being ground, and the obtained slurry was coated on a copper foil, then dried at 80°C for 24 h in vacuum, and the dried film was punched into an electrode sheet with a diameter of 12 mm. In a glove box filled with high-purity argon (H2O and O2 were both lower than 1 ppm), a metal sodium was used as the counter electrode and reference electrode, 1 mol / L NaPF6 / diethylene glycol dimethyl ether was used as the electrolyte, Celgard 2400 was used as the separator, and a CR2032 type button cell was assembled. Constant current charging and discharging was used, and the voltage range was 0-3 V.

[0084] Figure 5 The cycle performance of carbon aerogel and N / O co-doped carbon aerogel at a current density of 50 mA g -1 was shown. The first discharge capacity of N / O co-doped carbon aerogel was 625 mAh g -1 , which was much higher than that of carbon aerogel (353 mAh g -1 ). After 50 cycles, the discharge capacity of N / O co-doped carbon aerogel remained at 361 mAh g -1 , which was higher than that of carbon aerogel (240 mAh g -1 ).

[0085] Figure 6 The rate performance of carbon aerogel and N / O co-doped carbon aerogel electrodes was shown. The discharge capacity of N / O co-doped carbon aerogel at 25, 50, 100, 200, 500 and 1000 mA g -1 was 395, 387, 374, 353, 300 and 228 mAh g -1 , respectively. When the current density returned to 25 mA g -1 , the discharge capacity could return to 430 mAh g -1 , which showed excellent rate performance compared with the undoped carbon aerogel electrode.

[0086] While the application has been described by way of example with reference to preferred embodiments, it is to be understood that this application is not limited to the embodiments disclosed, but is intended to cover modifications and variations within the spirit and scope of the application. Therefore, the scope of the application is defined not by the detailed description of the application but by the following claims, wherein reference to an alternative embodiment includes reference to all features describing that embodiment.

Claims

1. A method for preparing a biomass-derived N / O co-doped carbon aerogel sodium-ion battery anode material, characterized in that, Includes the following steps: S1. After processing the biomass precursor, it is transferred to a hydrothermal reactor for heat treatment to obtain biomass hydrogel. S2. The biomass hydrogel obtained in step S1 is soaked in hot water to remove soluble impurities, and then freeze-dried to obtain biomass aerogel. S3. The biomass aerogel obtained in step S2 is heated to the required temperature under an inert atmosphere and then kept at that temperature to obtain carbon aerogel. S4. The carbon aerogel obtained in step S3 is ultrasonically dispersed in a mixed solvent composed of deionized water and diethylenetriamine, and ammonium molybdate is added. The mixture is stirred to obtain a suspension. The suspension is transferred to a hydrothermal reactor for reaction. After the reaction is completed, the mixture is cooled, and the cooled product is washed and dried. The obtained solid powder is then heat-treated under a nitrogen atmosphere to obtain N / O co-doped carbon aerogel sodium-ion battery anode material. In the suspension, the mass ratio of carbon aerogel to ammonium molybdate is 1:(10~20), and the volume ratio of deionized water to diethylenetriamine is 9:

5. The treatment conditions of the suspension in the hydrothermal reactor are: holding at 160~200 ℃ for 12~48 h. The heat treatment process of the solid powder under a nitrogen atmosphere is: heating to 600~1000 ℃ at a heating rate of 1~3° / min and holding for 1~3 h. The interlayer spacing of the N / O co-doped carbon aerogel sodium-ion battery anode material is higher than that of Na. + The critical interlayer spacing between hard carbon layers is beneficial for Na + Embedding and extraction.

2. The preparation method according to claim 1, characterized in that, The biomass precursor is one or more of the following: sugarcane, grapefruit peel, durian shell, and winter melon.

3. The preparation method according to claim 1, characterized in that, In step S1, the heat treatment temperature is 160~200℃ and the treatment time is 1 h~48 h.

4. The preparation method according to claim 1, characterized in that, In step S2, the hot water soaking temperature is 60~80℃, and the soaking time is 10 h~48 h.

5. The preparation method according to claim 1, characterized in that, In step S2, the freeze-drying temperature is -48℃ to -80℃, and the freeze-drying time is 1 to 5 days.

6. The preparation method according to claim 1, characterized in that, In step S3, the temperature is increased to 600-1200 °C at a heating rate of 1° / min to 5° / min, and held for 1-2 h to obtain carbon aerogel.

7. A biomass-derived N / O co-doped carbon aerogel sodium-ion battery anode material prepared by the method according to any one of claims 1-6.

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