High-capacity sodium-ion battery anode material, method for preparing same, and battery

Abstract

The application discloses a high-capacity sodium ion battery negative electrode material and a preparation method and battery thereof, and relates to the technical field of battery materials, in particular to a high-capacity sodium ion battery negative electrode material, a preparation method and battery thereof. The negative electrode material comprises a porous carbon layer, a plurality of micropores are arranged in the porous carbon layer, and the micropores are filled with graphite-like layer carbon microcrystals. The preparation method of the negative electrode material comprises the steps of template method deposition preparation of the porous carbon layer and graphite-like layer carbon microcrystal heat treatment preparation. The high-capacity sodium ion battery negative electrode material, the preparation method and the battery thereof have the characteristics of large sodium storage capacity, high first cycle coulomb efficiency, good cycle performance and excellent rate performance.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, specifically to a high-capacity sodium-ion battery anode material, its preparation method, and the battery thereof. Background Technology

[0002] The rapid development of new energy sources has greatly boosted the demand for large-scale energy storage technologies. Sodium-ion batteries, as a novel type of rechargeable battery, have attracted widespread attention in the field of large-scale energy storage due to the abundance and low cost of sodium resources. In sodium-ion battery systems, the anode material is one of the key factors determining battery performance. Therefore, to promote the industrialization of sodium-ion batteries, it is essential to develop high-performance, low-cost, and easily mass-producible sodium-ion battery anode materials. However, hard carbon materials, currently considered the most promising for application, still face many challenges in practical applications, including low sodium storage capacity, low initial coulombic efficiency, and poor cycle stability.

[0003] In response to this, Chinese invention patent CN114335523A discloses a method for preparing a hard carbon anode for high-energy-density sodium-ion batteries with excellent sodium storage performance. The hard carbon anode comprises porous carbon and chemical vapor deposition carbon for adjusting the surface pore size; the hard carbon anode retains the continuous pore structure inside the porous carbon. This invention designs a carbon-carbon composite structure with carbon coating through chemical vapor deposition, achieving control over the pore size of the porous carbon surface. Simultaneously, by combining the influence of precursor particle size, specific surface area, pore size, gas source concentration, and catalyst on sodium storage performance, a hard carbon anode with excellent initial coulombic efficiency, rate performance, and plateau capacity is designed, which has guiding significance for promoting the commercialization of high-energy-density sodium-ion batteries. However, it must be recognized that this hard carbon anode uses a structure where porous carbon particles are coated with deposited carbon. The amount of deposited carbon, the uniformity of coating, the deposition time, and the deposition rate all significantly affect its performance, resulting in poor process controllability. Furthermore, regarding the pore size of porous carbon, which ranges from 0.5 to 9 nm, its structural defects cause significant variability in size. Larger pore sizes can lead to increased metallicity of deposited sodium, increasing the risk of short circuits and reducing the specific surface area of ​​the material, thus decreasing sodium storage capacity. Smaller pore sizes, on the other hand, affect ion transport in the solid phase, leading to losses in rate performance and sodium storage capacity. Moreover, the deposition potential of porous sodium is very close to the deposition potential of metallic sodium. Therefore, during actual battery use, sodium dendrites are easily generated due to polarization, leading to short circuits and continuous capacity decay, which is detrimental to safety and battery performance. Summary of the Invention

[0004] The purpose of this invention is to provide a high-capacity sodium-ion battery anode material, its preparation method, and the battery itself, which features large sodium storage capacity, high first-cycle coulombic efficiency, good cycle performance, and excellent rate performance.

[0005] This invention can be achieved through the following technical solutions:

[0006] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, characterized in that: the micropores are filled with graphite-like carbon microcrystals.

[0007] The charge-discharge curve of hard carbon consists of a high-potential ramp region (>0.1 V vs. Na / Na+) and a low-potential plateau region (<0.1 V vs. Na / Na+), with the latter being particularly important for the energy density of sodium-ion batteries. The sodium storage performance of hard carbon is closely related to its microstructure. The capacity of the low-potential plateau region mainly comes from the combined contribution of graphite-like carbon microcrystals with suitable interlayer spacing and micropores with suitable pore size within the hard carbon microstructure. Therefore, this invention enhances the capacity of the plateau region by increasing the presence of graphite-like carbon microcrystals with suitable interlayer spacing and pore structures with suitable pore size in the hard carbon material, thereby improving the battery's energy density. Compared to existing pore-forming strategies, such as carbon oxide precursors, tightening the pore inlets of porous carbon, and using pore-forming agents (e.g., MgO particles, ethanol, etc.), the strategy of constructing graphite-like carbon microcrystals filling the microporous structure in this invention can effectively improve the sodium storage capacity of hard carbon materials, thereby increasing the battery's energy density.

[0008] Furthermore, the porous carbon includes microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 .

[0009] Furthermore, the volume of graphite-like carbon microcrystals filling the porous carbon accounts for 50-80% of the total pore volume, with the remaining unfilled pore volume being micropores. Compared to existing technologies, graphite-like microcrystals exhibit a higher sodium storage potential, but their theoretical capacity is limited (NaC8, 279 mAh g⁻¹). -1 Regarding sodium storage in porous layers, while the capacity limit is high, the sodium storage potential is close to the deposition potential of sodium metal. This makes the battery prone to sodium deposition during cycling, leading to capacity decay and safety hazards. Therefore, this invention addresses the shortcomings of using either graphite-like microcrystals alone by controlling the filling volume ratio of the porous layer, thus creating a complementary technology. This allows hard carbon to possess both a high sodium storage potential and a high sodium storage capacity, achieving safe and high-performance operation.

[0010] Furthermore, the carbon microcrystals filled with graphite-like layers have a pyrolytic carbon source of one or more of benzene, toluene, trimethylbenzene, acetylene, ethanol, formaldehyde, thiophene, pyridine, and / or sulfides.

[0011] Another aspect of the present invention relates to a method for preparing the above-mentioned high-energy-density sodium-ion battery anode material, comprising the following steps:

[0012] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0013] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0014] Further, in step S1, the inert carrier gas is nitrogen and / or argon, the carrier gas flow rate is 20-300 sccm, the controlled rise rate is 1-20℃ / min, the filling temperature is 600-1000℃, and the filling time is 0.5-5 h. These preparation conditions affect the filling rate, filling depth, and filling amount of graphite-like microcrystals. Specifically, increasing the carrier gas flow rate and filling temperature accelerates the filling rate while reducing the filling depth and amount of graphite-like microcrystals in the porous carbon pores, resulting in a lower graphite-like microcrystal content and a higher micropore volume. A longer filling time increases the content of filled graphite-like microcrystals and reduces the micropore volume. Therefore, these preparation conditions must be comprehensively considered to ensure that the material has optimal performance.

[0015] Further, in step S2, the inert carrier gas is nitrogen and / or argon, the heating rate is 1–10 °C, the heat treatment temperature is 800–1600 °C, and the heat treatment time is 0.5–8 h. Similarly, these preparation conditions also affect the graphitization degree of hard carbon materials. Specifically, a lower heating rate, a higher heat treatment temperature, and a longer heat treatment time will increase the content of graphite-like microcrystals in hard carbon materials, but this is not conducive to large-scale production in practice. Optimal preparation conditions need to be determined by comprehensively considering performance, cost, and energy consumption.

[0016] Another aspect of the present invention is to protect the negative electrode sheet of a sodium-ion battery, specifically, it is prepared using the above-mentioned negative electrode material.

[0017] Another aspect of the present invention is to protect sodium-ion batteries, specifically, batteries prepared using the aforementioned negative electrode material.

[0018] This invention discloses a high-capacity sodium-ion battery anode material, its preparation method, and the battery itself, which have the following beneficial effects:

[0019] The sodium-ion battery anode material of the present invention has the characteristics of controllable graphite nanodomains and pore structure, and can be used as a sodium-ion battery anode material. It exhibits extremely high sodium storage capacity (430 mAh / g), high first-cycle coulombic efficiency (88%) and good cycle stability (the capacity hardly decays after 100 cycles at a current density of 50 mA / g, and the capacity retention rate is as high as 80% after 1000 cycles at a current density of 500 mA / g). At the same time, it avoids the safety hazards caused by sodium dendrites and has obvious performance advantages. Attached Figure Description

[0020] Figure 1 This is a SEM image of the porous carbon template used in Example 1.

[0021] Figure 2 This is a TEM image of the porous carbon template used in Example 1.

[0022] Figure 3 The images show the XRD patterns of porous carbon, filled carbon, and high-temperature graphitized filled carbon from Application Example 1.

[0023] Figure 4 Raman diagrams of porous carbon, filled carbon, and high-temperature graphitized filled carbon from Application Example 1.

[0024] Figure 5 This is a SEM image of the carbon-filled material after high-temperature graphitization in Application Example 1.

[0025] Figure 6 This is a TEM image of the carbon-filled material after high-temperature graphitization in Application Example 1.

[0026] Figure 7 The graph shows the cycling performance of the high-temperature graphitized filled carbon obtained in Example 1 at a current density of 50 mA / g.

[0027] Figure 8 The graph shows the cycling performance of the high-temperature graphitized filled carbon obtained in Example 1 at a current density of 500 mA / g.

[0028] Figure 9 This is a rate performance diagram of the high-temperature graphitized filled carbon from Application Example 1. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solution of the present invention, the product of the present invention will be further described in detail below with reference to embodiments and accompanying drawings.

[0030] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, and the micropores are filled with graphite-like carbon microcrystals.

[0031] Furthermore, the porous carbon includes microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 .

[0032] Furthermore, the volume of graphite-like carbon microcrystals filling the porous carbon accounts for 50-80% of the total pore volume of the porous carbon, while the remaining unfilled pore volume is micropores.

[0033] Furthermore, the carbon microcrystals filled with graphite-like layers have a pyrolytic carbon source of one or more of benzene, toluene, trimethylbenzene, acetylene, ethanol, formaldehyde, thiophene, pyridine and / or sulfides.

[0034] Another aspect of the present invention relates to a method for preparing the above-mentioned high-energy-density sodium-ion battery anode material, comprising the following steps:

[0035] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0036] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0037] Further, in step S1, the inert carrier gas is nitrogen and / or argon, the carrier gas flow rate is 20-300 Sccm, the controlled rise rate is 1-20℃ / min, the filling temperature is 600-1000℃, and the filling time is 0.5-5 h.

[0038] Further, in step S2, the inert carrier gas is nitrogen and / or argon, the heating rate is 1-10℃, the heat treatment temperature is 800-1600℃, and the heat treatment time is 1-8h.

[0039] Another aspect of the present invention is to protect the negative electrode sheet of a sodium-ion battery, specifically, it is prepared using the above-mentioned negative electrode material.

[0040] Another aspect of the present invention is to protect sodium-ion batteries, specifically, batteries prepared using the aforementioned negative electrode material. Example 1

[0041] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, and the micropores are filled with graphite-like carbon microcrystals.

[0042] In this embodiment, the porous carbon is microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 The volume of graphite-like carbon microcrystals filling porous carbon accounts for 50-80% of the total pore volume of porous carbon, while the remaining unfilled pore volume is micropores.

[0043] Specifically, the carbon microcrystals filled with graphite-like layers have benzene, toluene, and trimethylbenzene as their pyrolytic carbon sources. Example 2

[0044] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, and the micropores are filled with graphite-like carbon microcrystals.

[0045] In this embodiment, the porous carbon is microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 The volume of graphite-like carbon microcrystals filling porous carbon accounts for 50-80% of the total pore volume of porous carbon, while the remaining unfilled pore volume is micropores.

[0046] Specifically, the graphite-like carbon microcrystals filled with pyrolysis carbon sources are acetylene, ethanol, formaldehyde, thiophene, pyridine, and sulfides. Example 3

[0047] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, and the micropores are filled with graphite-like carbon microcrystals.

[0048] In this embodiment, the porous carbon is microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 The volume of graphite-like carbon microcrystals filling porous carbon accounts for 50-80% of the total pore volume of porous carbon, while the remaining unfilled pore volume is micropores.

[0049] Specifically, the carbon microcrystals filled with graphite-like layers have pyrolytic carbon sources of benzene, toluene, formaldehyde, thiophene, pyridine, and sulfides. Example 4

[0050] The high-capacity sodium-ion battery anode materials of Examples 1-3 can be prepared using the following methods:

[0051] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0052] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0053] Specifically, in step S1, the inert carrier gas is nitrogen and argon, the carrier gas flow rate is 300 Sccm, the controlled rise rate is 10℃ / min, the filling temperature is 600℃, and the filling time is 5 h.

[0054] Specifically, in step S2, the inert carrier gas is nitrogen and argon, the heating rate is 10°C, the heat treatment temperature is 1300°C, and the heat treatment time is 1 hour. Example 5

[0055] The high-capacity sodium-ion battery anode materials of Examples 1-3 can be prepared using the following methods:

[0056] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0057] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0058] Specifically, in step S1, the inert carrier gas is nitrogen, the carrier gas flow rate is 200 Sccm, the controlled rise rate is 2℃ / min, the filling temperature is 1000℃, and the filling time is 3 h.

[0059] Specifically, in step S2, the inert carrier gas is nitrogen and / or argon, the heating rate is 5°C, the heat treatment temperature is 1100°C, and the heat treatment time is 8 hours. Example 6

[0060] The high-capacity sodium-ion battery anode materials of Examples 1-3 can be prepared using the following methods:

[0061] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0062] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0063] Specifically, in step S1, the inert carrier gas is argon, the carrier gas flow rate is 20 Sccm, the controlled rise rate is 20℃ / min, the filling temperature is 800℃, and the filling time is 0.5 h.

[0064] Specifically, in step S2, the inert carrier gas is nitrogen, the heating rate is 2°C, the heat treatment temperature is 1600°C, and the heat treatment time is 4 hours. Example 7

[0065] The high-capacity sodium-ion battery anode materials of Examples 1-3 can be prepared using the following methods:

[0066] S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to carry in the pyrolytic carbon source for heating treatment to obtain filling carbon with pyrolytic carbon inside the porous carbon.

[0067] S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to graphitize and regulate the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

[0068] Specifically, in step S1, the inert carrier gas is nitrogen and argon, the carrier gas flow rate is 160 Sccm, the controlled rise rate is 10℃ / min, the filling temperature is 800℃, and the filling time is 3 h.

[0069] Specifically, in step S2, the inert carrier gas is nitrogen and argon, the heating rate is 4°C, the heat treatment temperature is 1200°C, and the heat treatment time is 6 hours. Example 8

[0070] Another aspect of the present invention is to protect the negative electrode sheet of a sodium-ion battery, specifically, it is prepared using the above-mentioned negative electrode material. Example 9

[0071] Another aspect of the present invention is to protect sodium-ion batteries, specifically, batteries prepared using the aforementioned negative electrode material.

[0072] Application Example 1

[0073] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon contains a plurality of micropores, and the micropores are filled with graphite-like carbon microcrystals. Its preparation and testing include the following steps:

[0074] S11: Place activated carbon in a tube furnace and pass nitrogen gas through it at a flow rate of 100 Sccm to carry benzene vapor in.

[0075] Specifically, the S11 activated carbon is the commercially available activated carbon YEC-8A, with a specific surface area of ​​1600 m². 2 / g, with an average pore size of 0.9nm. The measured true density is 2.16 cm³. 3 / g. Its SEM and TEM results are as follows: Figure 1 and 2 As shown in the image, the TEM image reveals that almost no graphite-like carbon microcrystalline regions are present in the activated carbon template. Its XRD and Raman spectra are as follows. Figure 3 and Figure 4 As shown.

[0076] S12: Heated to 700℃ at a heating rate of 5℃ / min, held at that temperature for 3 hours, and then allowed to cool naturally to room temperature. The measured true density was 1.80 cm³. 3 / g indicates the formation of internal pores within the filled carbon, leading to a decrease in true density. Its XRD and Raman spectra are as follows: Figure 3 and Figure 4 As shown.

[0077] S13: The filled carbon obtained in S12 was placed in a tube furnace and heated to 1300℃ at a heating rate of 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and then cooled to room temperature at a programmed cooling rate of 5℃ / min. This further graphitized the filled carbon, yielding the high-temperature graphitized filled carbon. Its SEM and TEM images are shown below. Figure 5 and 6 As shown. Its XRD and Raman spectra are as follows. Figure 3 and Figure 4 As shown in the image, the TEM image reveals that the activated carbon template is filled with a large number of graphite-like carbon microcrystalline regions, as well as numerous microporous regions. The full width at half maximum (FWHM) of the XRD patterns of porous carbon, filled carbon, and high-temperature graphitized filled carbon decreases sequentially, while the I0.05 in the Raman spectrum also increases. D / I G The decreasing order indicates an increase in the degree of graphitization of the material and an increase in the size of the graphite-like microcrystals, which in turn suggests that the graphite-like microcrystals are being filled into the pores of the active porous carbon.

[0078] S14: Nitrogen adsorption-desorption tests and He gas true density tests were performed on the activated carbon, materials obtained from S12 and S13. The open pore volume and closed pore volume were calculated, and then the total pore volume was obtained. The total pore volumes of porous carbon, filled carbon, and high-temperature graphitized filled carbon were 0.86, 0.18, and 0.24 cm³, respectively. 3 / g indicates that some pores were filled with graphite-like microcrystals, while some pores were left unfilled.

[0079] S15: Using the material obtained in S13 as the active material, CMC and SBR as binders, and SP as conductive carbon, a film was coated with an active material:CMC:SBR:SP ratio of 95:1.5:2:1.5. After drying, the film was sliced ​​and assembled into 2032 coin cells in a glove box. Cyclic performance tests were performed using Neware software. Its electrochemical performance is as follows: Figure 7-9 As shown, the obtained material exhibits extremely high sodium storage capacity (430 mAh / g) and high first-cycle coulombic efficiency (88%). It also demonstrates excellent cycling performance, with almost no capacity decay after 100 cycles at a current density of 50 mA / g. Figure 7 After cycling for 1000 cycles at a current density of 500 mA / g, the capacity retention is as high as 80%. Figure 8 It also exhibits good rate performance, maintaining a capacity of 290.7 mAh / g at a current density of 1 A / g. Figure 9 This material exhibits leading sodium storage performance among hard carbon materials. Compared to the preparation method disclosed in Chinese invention patent CN114335523A, the amount, uniformity, and consistency of deposited carbon are more controllable in this method. Furthermore, interlayer sodium storage via graphite-like microcrystalline intercalation exhibits a higher sodium storage potential compared to pore-deposited sodium storage, reducing the problems of short circuits and capacity decay caused by sodium metal precipitation during battery use, and thus facilitating the commercial application of hard carbon anode materials for sodium-ion batteries.

[0080] Application Example 2

[0081] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon contains a plurality of micropores, and the micropores are filled with graphite-like carbon microcrystals. Its preparation and testing include the following steps:

[0082] S11: Place porous carbon in a tube furnace and introduce nitrogen gas at a flow rate of 100 Sccm to carry in pyridine vapor as a carrier gas.

[0083] Specifically, the S11 porous carbon is the commercially available activated carbon YEC-8A, with a specific surface area of ​​1600 m². 2 / g, with an average pore size of 0.9nm and a true density of 2.16 cm3 / g.

[0084] S12: Heat to 700℃ at a heating rate of 5℃ / min, hold at that temperature for 3 hours, and then allow to cool naturally to room temperature.

[0085] S13: The carbon filler obtained in S12 is placed in a tube furnace and heated to 1300℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. The temperature is held for 2 hours and then cooled to room temperature at a cooling rate of 5℃ / min. The carbon filler is further graphitized to obtain high-temperature graphitized carbon filler.

[0086] S14: Using the material obtained in S13 as the active material, CMC and SBR as binders, and SP as conductive carbon, a film was coated with active material:CMC:SBR:SP in a ratio of 95:1.5:2:1.5. After drying, the film was sliced ​​and assembled into 2032 coin cells in a glove box. Cycle performance tests were performed using Neware software.

[0087] Application Example 3

[0088] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon contains a plurality of micropores, and the micropores are filled with graphite-like carbon microcrystals. Its preparation and testing include the following steps:

[0089] S11: Place activated carbon in a tube furnace and introduce nitrogen gas at a flow rate of 100 Sccm to carry in thiophene vapor.

[0090] Specifically, the porous carbon used in step one is commercially available activated carbon YEC-8A, with a specific surface area of ​​1600 m². 2 / g, average pore size 0.9nm, true density 2.16 cm³ / g 3 / g.

[0091] S12: Heat to 700℃ at a heating rate of 5℃ / min, hold at that temperature for 3 hours, and then allow to cool naturally to room temperature.

[0092] S13: The carbon filler obtained in S12 is placed in a tube furnace and heated to 1300℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. The temperature is held for 2 hours and then cooled to room temperature at a cooling rate of 5℃ / min. The carbon filler is further graphitized to obtain high-temperature graphitized carbon filler.

[0093] S14: Using the material obtained in S13 as the active material, CMC and SBR as binders, and SP as conductive carbon, a film was coated with active material:CMC:SBR:SP in a ratio of 95:1.5:2:1.5. After drying, the film was sliced ​​and assembled into 2032 coin cells in a glove box. Cycle performance tests were performed using Neware software.

[0094] Application Example 4

[0095] This invention discloses a high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon contains a plurality of micropores, and the micropores are filled with graphite-like carbon microcrystals. Its preparation and testing include the following steps:

[0096] S11: Place porous carbon in a tube furnace and introduce acetylene gas at a flow rate of 100 Sccm.

[0097] Specifically, the porous carbon used in step one is commercially available activated carbon YEC-8A, with a specific surface area of ​​1600 m². 2 / g, with an average pore size of 0.9nm and a true density of 2.16 cm3 / g.

[0098] S12: Heat to 700℃ at a heating rate of 5℃ / min, hold at that temperature for 3 hours, and then allow to cool naturally to room temperature.

[0099] S13: The carbon filler obtained in S12 is placed in a tube furnace and heated to 1300℃ at a heating rate of 5℃ / min under a nitrogen atmosphere. The temperature is held for 2 hours and then cooled to room temperature at a cooling rate of 5℃ / min. The carbon filler is further graphitized to obtain high-temperature graphitized carbon filler.

[0100] S14: Using the material obtained in step three as the active material, CMC and SBR as binders, and SP as conductive carbon, a film is coated with active material:CMC:SBR:SP in a ratio of 95:1.5:2:1.5. After drying, the film is sliced ​​and assembled into 2032 coin cells in a glove box. Cycle performance tests are performed using Neware software.

[0101] The above embodiments are merely specific examples of the present invention, and their descriptions are quite specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these obvious substitutions all fall within the protection scope of the present invention.

Claims

1. A high-capacity sodium-ion battery anode material, comprising porous carbon, wherein the porous carbon has a plurality of micropores inside, characterized in that: The micropores are filled with graphite-like carbon microcrystals. The volume of the graphite-like carbon microcrystals filling the porous carbon accounts for 50-80% of the total pore volume of the porous carbon, and the remaining unfilled pore volume is micropores. The pyrolysis carbon source for graphite-like carbon microcrystals is one or more of benzene, toluene, trimethylbenzene, acetylene, ethanol, formaldehyde, thiophene, pyridine and / or sulfides; The preparation method of this negative electrode material includes the following steps: S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to bring in the pyrolytic carbon source. The carbon is heated to prepare filling carbon with pyrolytic carbon inside the porous carbon. The filling temperature is 600-1000℃. S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to perform graphite-like conditioning of the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals. The heat treatment temperature is 800-1600℃ to obtain the final anode material.

2. The high-capacity sodium-ion battery anode material according to claim 1, characterized in that: The porous carbon is microporous carbon and mesoporous carbon, with an average pore size of 0.4-4 nm and a specific surface area of ​​1000-3000 m². 2 g -1 .

3. A method for preparing the high-capacity sodium-ion battery anode material according to claim 1 or 2, characterized in that... Includes the following steps: S1. Preparation of filling carbon: Using porous carbon as a template, it is placed in a high-temperature furnace, and an inert gas is introduced as a carrier gas to bring in the pyrolytic carbon source. The carbon is heated to prepare filling carbon with pyrolytic carbon inside the porous carbon. S2. High-temperature preparation of graphite-like carbon microcrystals: The filled carbon obtained in step S1 is placed in a tube furnace and heated under an inert gas to perform graphite-like conditioning of the pyrolytic carbon inside the filled carbon to form graphite-like carbon microcrystals, thus obtaining the final anode material.

4. The method for preparing the high-capacity sodium-ion battery anode material according to claim 3, characterized in that: In step S1, the inert gas is nitrogen and / or argon, the carrier gas flow rate is 20-300 Sccm, the heating rate is controlled at 1-20℃ / min, and the filling time is 0.5-5 h.

5. The method for preparing the high-capacity sodium-ion battery anode material according to claim 3, characterized in that: In step S2, the inert gas is nitrogen and / or argon, the heating rate is 1-10℃, and the heat treatment time is 0.5-8h.

6. A sodium-ion battery negative electrode sheet, characterized in that: It is prepared using the negative electrode material described in claim 1 or 2.

7. A sodium-ion battery, characterized in that: It is prepared using the negative electrode material described in claim 1 or 2.

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