Application of asphaltene in preparation of sodium ion battery hard carbon negative electrode material, negative electrode material and negative electrode plate

Abstract

The invention relates to the technical field of asphaltene recycling, and discloses application of asphaltene in preparation of a sodium ion battery hard carbon negative electrode material, the negative electrode material and a negative electrode plate. Wherein asphaltene is used for preparing the sodium-ion battery hard carbon negative electrode material, and the preparation method of the sodium-ion battery hard carbon negative electrode material comprises the following steps: putting asphaltene powder in an air atmosphere for pre-oxidation treatment to obtain an intermediate product; the temperature of the pre-oxidation treatment is 200 to 350 DEG C; and performing carbonization treatment on the intermediate product in an inert atmosphere to obtain the sodium-ion battery hard carbon negative electrode material. According to the preparation method, asphaltene which is originally used as industrial waste is subjected to modification treatment through air pre-oxidation, and the asphaltene is modified into a potentially applicable hard carbon negative electrode material of the sodium ion battery through high-temperature carbonization in an inert atmosphere. The application scene of asphaltene is further widened, and the purpose of recycling waste resources is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of asphaltene recovery and reuse, and in particular to an application of asphaltene in preparing a hard carbon negative electrode material for a sodium ion battery, a negative electrode material, and a negative electrode sheet. Background Art

[0002] Asphaltene is a high-molecular compound derived from fossil petroleum through pyrolysis or chemical treatment. While abundant, inexpensive, and guaranteed to be in constant supply, as an industrial waste, asphaltene has not been properly utilized, and there are virtually no reports of its high-value utilization. This results in a waste of resources and damage to the ecological environment.

[0003] Therefore, the existing technology needs to be further improved and enhanced. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide an application of asphaltene in the preparation of a hard carbon negative electrode material for sodium ion batteries, a negative electrode material, and a negative electrode sheet, aiming to solve the problem of insufficient utilization of existing asphaltene, resulting in waste of resources.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions: an application of asphaltene in the preparation of hard carbon negative electrode materials for sodium ion batteries;

[0006] The preparation method of the hard carbon negative electrode material for sodium ion batteries comprises the following steps:

[0007] The asphaltene powder is placed in an air atmosphere for pre-oxidation treatment to obtain an intermediate product; the pre-oxidation treatment temperature is 200 to 350°C;

[0008] The intermediate product is carbonized in an inert atmosphere to obtain a hard carbon negative electrode material for a sodium ion battery.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0010] As a preferred technical solution, the sodium asphaltene is used in the preparation of a hard carbon negative electrode material for a sodium ion battery, wherein the pre-oxidation treatment time is 1 to 8 hours and the heating rate is 5 to 15°C / min.

[0011] As a preferred technical solution, the asphaltene is used in the preparation of a hard carbon negative electrode material for a sodium ion battery, wherein the carbonization treatment temperature is 800-1500°C, the carbonization time is 2-10h, and the heating rate is 1-2°C / min.

[0012] As a preferred technical solution, the use of asphaltene in preparing a hard carbon negative electrode material for a sodium ion battery, wherein the preparation method of the asphaltene powder comprises:

[0013] The solid soft-based carbon material is dissolved in a solution, and is sequentially centrifuged, vacuum dried, and crushed to obtain the asphaltene powder; the solid soft-based carbon material is a dark brown mixture of hydrocarbons of different molecular weights and their non-metallic derivatives.

[0014] As a preferred technical solution, the asphaltene is used in the preparation of a hard carbon negative electrode material for a sodium ion battery, wherein the solution is a combination of any two of toluene, n-heptane, n-octane, methanol, tetrahydrofuran, water, dichloromethane, n-hexane, isooctane, isopropanol and acetonitrile.

[0015] As a preferred technical solution, the asphaltene is used in the preparation of a hard carbon negative electrode material for a sodium ion battery, wherein the particle size of the asphaltene powder is less than 30 μm.

[0016] As a preferred technical solution, the asphaltene is used in the preparation of a hard carbon negative electrode material for a sodium ion battery, wherein the vacuum drying temperature is 60 to 110°C.

[0017] In a second aspect, a negative electrode material is provided, wherein the negative electrode material is the hard carbon negative electrode material for sodium ion batteries described above.

[0018] In a third aspect, a negative electrode sheet is provided, wherein the negative electrode sheet comprises the sodium ion battery hard carbon negative electrode material described in the second aspect.

[0019] As a preferred technical solution, the negative electrode sheet, wherein the preparation method of the negative electrode sheet includes:

[0020] Grinding the sodium ion battery hard carbon negative electrode material into powder, and mixing the powder with a conductive agent, a binder, and deionized water or N-methylpyrrolidone to obtain a slurry;

[0021] The slurry is coated on the surface of the negative electrode current collector of the sodium ion battery, and the negative electrode sheet is obtained after drying.

[0022] Beneficial Effects: Compared to existing technologies, this invention transforms asphaltene, previously considered industrial waste, into a potential hard carbon anode material for sodium-ion batteries by pre-oxidizing it with air and then carbonizing it in an inert atmosphere at high temperature. This further broadens the application of asphaltene and achieves the goal of recycling waste resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1The first week charge and discharge curve of the hard carbon negative electrode material prepared in Example 1 for sodium ion battery;

[0024] Figure 2 This is a rate performance diagram of the hard carbon negative electrode material prepared in Example 1 for sodium ion batteries;

[0025] Figure 3 This is the X-ray diffraction pattern of the hard carbon negative electrode material prepared in Example 1. DETAILED DESCRIPTION

[0026] The present invention provides the use of asphaltene in preparing a hard carbon anode material for sodium ion batteries, anode materials, and anode sheets. To further clarify the objectives, technical solutions, and effects of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0027] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various orders in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary order unless otherwise specified that a certain order must be followed. The serial numbers themselves, such as "first", "second", etc., assigned to the components herein are only used to distinguish the objects described and do not have any order or technical meaning.

[0028] The present invention provides an application of asphaltene in preparing a hard carbon negative electrode material for a sodium ion battery. The preparation method of the hard carbon negative electrode material for a sodium ion battery comprises the following steps:

[0029] The asphaltene powder is placed in an air atmosphere for pre-oxidation treatment to obtain an intermediate product; the temperature of the pre-oxidation treatment is 200-350° C.; the intermediate product is carbonized in an inert atmosphere to obtain a sodium ion battery hard carbon negative electrode material.

[0030] The pre-oxidized asphaltene in the present invention has introduced more oxygen functional groups and defects, expanded the interlayer spacing, and formed a large number of open pores, effectively improving the sodium storage capacity. The introduction of air pre-oxidation to treat asphaltene can minimize the use of acidic and alkaline chemical reagents in the production process, reduce energy consumption and save time costs. In the subsequent final carbonization process, the carbon layer structure cannot be arranged in order due to the large number of carbon-oxygen bonds formed, accompanied by the shrinkage of the open pores, and finally a high-capacity, high-closed micropore density sodium ion battery hard carbon negative electrode material is prepared in the asphaltene precursor, turning the original industrial waste or waste into hard carbon with application value, realizing the reuse of asphaltene.

[0031] In the present invention, asphaltene powder can be obtained by dissolving petroleum asphalt in a solvent, extracting asphaltene from it by industrial extraction, and crushing and sieving the asphaltene to obtain asphaltene powder. The particle size of the powder should be less than 30 μm to improve the oxidation efficiency in the air, and the particle size requirement is easy to achieve in ball milling. The solution used can be a mixture of toluene, n-heptane, n-octane, methanol, tetrahydrofuran, water, dichloromethane, n-hexane, isooctane, isopropanol and acetonitrile, or it can be a single type of solvent. For example, toluene / methanol = 9:1, tetrahydrofuran (THF) / water = 7:3, dichloromethane / methanol = 8:2, n-hexane / toluene = 7:3, isooctane / methanol = 6:4, toluene / acetonitrile = 8:2, tetrahydrofuran / isopropanol = 5:5, n-heptane (100%), toluene (100%), toluene / n-heptane / methanol

[0032] =5:3:2, isooctane / methanol / isopropanol =4:5:1, tetrahydrofuran / isopropanol / acetonitrile / water

[0033] =5:3:1:1. It should be noted that it is possible to adjust the proportion of each solvent from 1% to 100%.

[0034] In one implementation of the present invention, asphaltene powder is pre-oxidized in an air atmosphere, and the pre-oxidation temperature can be 200° C. to 220° C., 220° C. to 240° C., 240° C. to 260° C., 260° C. to 280° C., 280° C. to 300° C., 300° C. to 320° C., or 320° C. to 350° C. By controlling the pre-oxidation temperature, more oxygen functional groups are introduced into the asphaltene, the spacing between layers is expanded, and a large number of open pores are formed. During the final carbonization process, the open pores shrink into closed or semi-closed micropores, thereby increasing the sodium storage capacity. When the hard carbon is prepared and used as the negative electrode of a sodium ion battery, the sodium ion battery has a higher first coulombic efficiency and more stable long-cycle performance.

[0035] Furthermore, the pre-oxidation treatment time is 1 to 8 hours, and the heating rate is 5 to 15° C. / min. Controlling the time and heating rate can avoid insufficient oxidation and prevent the size (pore diameter) and density of the synthesized open pores from being inappropriate.

[0036] In one implementation of the present invention, the oxidized asphaltene is subjected to high-temperature carbonization in an inert atmosphere. The high-temperature carbonization temperature may be 800° C. to 900° C., 900° C. to 1000° C., 1000° C. to 1100° C., 1100° C. to 1200° C., 1200° C. to 1300° C., 1300° C. to 1400° C., or 1400° C. to 1500° C. The carbonization time is 2 h to 3 h, 3 h to 4 h, 4 h to 5 h, 5 h to 6 h, 6 h to 7 h, 7 h to 8 h, 8 h to 9 h, or 9 h to 10 h. The inert gas may be nitrogen or argon.

[0037] Based on the same inventive concept, the present invention also provides a negative electrode material, wherein the negative electrode material is the above-mentioned hard carbon negative electrode material for sodium ion batteries.

[0038] Based on the same inventive concept, the present invention also provides a negative electrode sheet, wherein the negative electrode sheet includes the above-mentioned sodium ion battery hard carbon negative electrode material.

[0039] Specifically, the sodium ion battery negative electrode material is used to prepare the sodium ion battery negative electrode plate, and the steps are as follows:

[0040] The prepared sodium-ion battery negative electrode material is crushed and sieved to a particle size of 1-20 μm. A conductive agent, a binder (CMC / SBR), and deionized water are added, mixed, and coated on the surface of the sodium-ion battery negative electrode current collector. The cut pieces are dried to obtain sodium-ion battery negative electrode sheets, which can be used in sodium-ion half-cells. The mass ratio of the sodium-ion battery hard carbon negative electrode material, the conductive agent, the binder, and deionized water or N-methylpyrrolidone is 80-90:5-10:2.5-5:4-6. Carbon-coated copper foil or carbon-coated aluminum foil can be used for the sodium-ion battery negative electrode current collector. The drying temperature of the sodium-ion battery negative electrode sheet is 90-120°C, and the drying time is 8-18 hours. It should be noted that when the solvent is or N-methylpyrrolidone, the binder is PVDF.

[0041] The technical solution provided by the present invention is further explained below through specific preparation examples.

[0042] Example 1

[0043] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0044] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0045] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0046] Example 2

[0047] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0048] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 250°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0049] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0050] Example 3

[0051] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0052] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 220°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0053] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0054] Example 4

[0055] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0056] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 310°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0057] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0058] Example 5

[0059] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0060] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 6 hours to obtain intermediate product B;

[0061] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0062] Example 6

[0063] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0064] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 9 hours to obtain intermediate product B;

[0065] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0066] Example 7

[0067] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0068] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 12 hours to obtain intermediate product B;

[0069] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0070] Example 8

[0071] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0072] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 2 hours to obtain intermediate product B;

[0073] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0074] Example 9

[0075] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0076] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 1 hour to obtain intermediate product B;

[0077] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0078] Example 10

[0079] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0080] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0081] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1300°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0082] Example 11

[0083] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0084] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0085] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1400°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0086] Example 12

[0087] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0088] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0089] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1100°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0090] Example 13

[0091] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0092] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0093] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 6 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0094] Example 14

[0095] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0096] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0097] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 9 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0098] Example 15

[0099] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-heptane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0100] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0101] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min and a holding time of 1 hour to obtain an asphaltene-derived sodium ion battery hard carbon negative electrode material.

[0102] Example 16

[0103] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-hexane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0104] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0105] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0106] Example 17

[0107] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of isooctane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0108] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0109] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0110] Example 18

[0111] (1) Take 5 g of petroleum asphalt precursor material, dissolve it in 20 ml of toluene and 20 ml of n-pentane in a ratio of 1:1, stir for 3 hours, centrifuge at 5000 rpm, remove the supernatant, and take the centrifuged product and dry it in vacuum at 80 degrees for 12 hours to obtain intermediate product A.

[0112] (2) Intermediate product A was crushed and sieved to control the particles to be less than 30 μm, and then pre-oxidized in an air atmosphere, heated to 280°C at a heating rate of about 10°C / min, and kept at this temperature for 3 hours to obtain intermediate product B;

[0113] (3) The intermediate product B was taken and placed in an inert atmosphere and heated to 1200°C at a heating rate of about 1.5°C / min for 3 hours to obtain an asphaltene-derived hard carbon negative electrode material for sodium ion batteries.

[0114] The electrochemical performance of the obtained materials was tested according to the following method:

[0115] The prepared sodium ion battery hard carbon / soft carbon negative electrode material, Super P, CMC and SBR were mixed in a mass ratio of 80:10:5:5, and 450 μL of deionized water was added to mix into a slurry. The electrode slurry was evenly coated on the carbon-coated aluminum foil using a 100 μm four-sided preparation device, and then vacuum dried in an oven at 100 ° C for 12 hours. The electrode sheet was cut into discs with a diameter of 12 mm using a punching machine, and metallic sodium was used as the counter electrode, 1 mol / L NaClO4TETRAGLYME as the electrolyte, and glass fiber as the diaphragm. CR2032 button batteries were assembled in a glove box. The above button battery was subjected to constant current charge and discharge tests with a current density of 20 mA g -1 , the voltage range is 3 to 0.002 V. The electrode materials prepared in Examples 1-15 were assembled into CR 2032 button batteries for electrochemical performance testing. The results are shown in Table 1.

[0116] Table 1 Electrochemical performance of Examples 1-15

[0117]

[0118] From the comparison in Table 1 above, it can be seen that the asphaltene-derived sodium ion battery hard carbon negative electrode material prepared in Example 1 has a higher first coulombic efficiency, a larger first-week charging specific capacity, and a better capacity retention rate compared with the sodium ion battery hard carbon negative electrode of other examples, which shows that the asphaltene air pre-oxidation defined in the present invention can prepare a sodium ion battery hard carbon negative electrode with a high specific capacity.

[0119] like Figures 1 to 3 Shown are the charge and discharge curve diagram, rate performance diagram, and X-ray diffraction spectrum of the hard carbon negative electrode material of Sample Example 1.

[0120] Figure 1 The horizontal axis is the specific capacity (unit: mAh g -1 ), the vertical axis is voltage (unit: V); during discharge, the voltage starts to decrease from a high potential (about 3V) and ends when the discharge reaches 0.002V. The charging process is the opposite, from 0.002V to 3V.

[0121] Figure 2 In the figure, the horizontal axis is the cycle number, and 10 cycles are performed at each gradually increasing current density. The vertical axis on the left is the specific capacity (unit: mAh g -1 ), the right axis vertical axis is the coulomb efficiency (unit: %). From left to right, every 10 cycles is a section, and the current density is: 20mAg -1 , 30mAg -1, 50mAg -1 , 100mAg -1 and 50mAg -1 After the current density fluctuation and high current rapid charge and discharge, the battery rate performance is tested by charging and discharging with a relatively small current. -1 When charged and discharged at a current density of , the specific capacity and coulombic efficiency of Example 1 fluctuate very little, indicating that the prepared asphaltene precursor-derived sodium ion battery hard carbon negative electrode material has good electrochemical charge and discharge rate performance.

[0122] Figure 3 In the figure, the abscissa is the diffraction angle (twice the X-ray incident angle, unit: degrees), and the ordinate is the diffraction peak intensity (unit: au). The characteristic peaks of the prepared asphaltene precursor-derived sodium-ion battery hard carbon anode material appear at 23.8° and 43.2°, respectively. These broad diffraction peaks represent an amorphous state and correspond to the 002 and 100 crystal planes of the hard carbon material, indicating sufficient carbonization and the prepared hard carbon material exhibits the characteristics of amorphous carbon.

[0123] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. Application of asphaltene in the preparation of hard carbon negative electrode materials for sodium ion batteries; The preparation method of the hard carbon negative electrode material for sodium ion batteries comprises the following steps: The asphaltene powder is placed in an air atmosphere for pre-oxidation treatment to obtain an intermediate product; the pre-oxidation treatment temperature is 200 to 350°C; The intermediate product is carbonized in an inert atmosphere to obtain a hard carbon negative electrode material for a sodium ion battery.

2. The use of asphaltene according to claim 1 in preparing a hard carbon negative electrode material for sodium ion batteries, characterized in that: The pre-oxidation treatment time is 1 to 8 hours, and the heating rate is 5 to 15° C. / min.

3. The use of asphaltene according to claim 1 in preparing a hard carbon negative electrode material for sodium ion batteries, characterized in that: The temperature of the carbonization treatment is 800-1500° C., the carbonization time is 2-10 hours, and the heating rate is 1-2° C. / min.

4. The use of asphaltene in preparing a hard carbon negative electrode material for sodium ion batteries according to claim 1, characterized in that: The preparation method of the asphaltene powder comprises: The solid soft-based carbon material is dissolved in a solution, and is sequentially centrifuged, vacuum dried, and crushed to obtain the asphaltene powder; the solid soft-based carbon material is a dark brown mixture of hydrocarbons of different molecular weights and their non-metallic derivatives.

5. The use of asphaltene in preparing a hard carbon negative electrode material for sodium ion batteries according to claim 4, characterized in that: The solution is selected from one or more combinations of toluene, n-heptane, n-octane, methanol, tetrahydrofuran, water, dichloromethane, n-hexane, isooctane, isopropanol and acetonitrile.

6. The use of asphaltene in preparing a hard carbon negative electrode material for sodium ion batteries according to claim 1, characterized in that: The particle size of the asphaltene powder is less than 30 μm.

7. The use of asphaltene in preparing a hard carbon negative electrode material for sodium ion batteries according to claim 4, characterized in that: The vacuum drying temperature is 60-110°C.

8. A negative electrode material, characterized in that The negative electrode material is the hard carbon negative electrode material for sodium ion batteries according to claim 1.

9. A negative electrode sheet, characterized in that: The negative electrode sheet comprises the sodium ion battery hard carbon negative electrode material according to claim 8.

10. The negative electrode sheet according to claim 9, characterized in that: The method for preparing the negative electrode sheet includes: The sodium ion battery hard carbon negative electrode material is crushed into powder, and the powder is mixed with a conductive agent, a binder and a solvent to obtain a slurry; the solvent is deionized water or N-methylpyrrolidone; The slurry is coated on the surface of the negative electrode current collector of the sodium ion battery, and the negative electrode sheet is obtained after drying.

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