Sodium-ion battery petroleum coke (green coke)-based hard carbon negative electrode material as well as preparation method and application thereof

Abstract

The invention discloses a sodium ion battery petroleum coke (green coke)-based hard carbon negative electrode material as well as a preparation method and application thereof, and relates to the technical field of new energy materials. According to the method, petroleum coke (green coke) and glucose are used as raw materials and are mixed according to a certain mass ratio, presintering and high-temperature carbonization are performed in an inert atmosphere to obtain a hard carbon material, and the hard carbon material is used for preparing the high-specific-capacity sodium ion battery. The method is simple in process, green and environment-friendly in raw material and suitable for batch production, and the prepared hard carbon material has excellent electrochemical performance and can be used as an ideal sodium ion battery negative electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy materials, and in particular to a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and a preparation method and application thereof. Background Art

[0002] Lithium-ion batteries are now widely used in energy storage systems, especially in electric vehicles and portable electronic products. The shortage of lithium resources has limited their application in large-scale power storage. Sodium-ion batteries and lithium-ion batteries have similar physical and chemical properties, and sodium resources are widely distributed and inexpensive, making sodium-ion batteries suitable for large-scale power storage. Electrode materials are particularly important in sodium-ion batteries, and many sodium-ion battery positive electrode materials have been developed at this stage. However, there is no suitable negative electrode material. Therefore, it is very important to study high-performance sodium-ion battery negative electrodes.

[0003] Hard carbon is considered as one of the choices for negative electrode materials of sodium ion batteries due to its rich defects and stable structure. Hard carbon is a carbon material that is difficult to graphitize, and the orientation of graphite crystallites is random. At the same time, the large number of defects contained inside are conducive to the storage of sodium ions.

[0004] At present, the production of hard carbon materials is mainly obtained by pyrolyzing biomass materials. However, due to the wide range of sources and different types of biomass materials, it is impossible to unify the raw materials and obtain consistent electrochemical performance during large-scale production.

[0005] Petroleum coke (green coke) is an industrial product obtained from petroleum raw materials. Untreated petroleum coke (green coke) easily forms a graphitized structure at high temperatures, and cannot be directly used in sodium-ion batteries due to factors such as its small interlayer spacing. However, due to its stable source and low price, petroleum coke (green coke) is processed through certain processes to prepare high-performance hard carbon materials, which can be used in sodium-ion batteries. Summary of the invention

[0006] The purpose of the present invention is to provide a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and its preparation method and application, aiming to solve the problems of high material cost and poor performance consistency of biomass carbon materials.

[0007] The present invention provides a sodium ion battery petroleum coke (green coke)-based hard carbon negative electrode material and a preparation method and application thereof. Glucose and petroleum coke (green coke) are mixed in a mass ratio of 9:1-1:9, pre-sintered in an inert atmosphere and carbonized at high temperature to obtain the hard carbon material.

[0008] In a first aspect, the preparation method of the hard carbon negative electrode material comprises the following steps:

[0009] Step 1): Glucose and petroleum coke (raw coke) are mixed to obtain a mixture powder, wherein the mass ratio of glucose to petroleum coke (raw coke) is 9:1-1:9.

[0010] Step 2): The mixture obtained in step 1) is heated to 150-700°C under an inert atmosphere, the pre-sintering time is 1-10h, the heating rate is 1-10°C / min, and the inert atmosphere is at least one of nitrogen or argon.

[0011] Step 3): The pre-sintered powder obtained in step 2) is heated to 800-1500°C under an inert atmosphere, the carbonization time is 1-10h, and the heating rate is 1-10°C / min to obtain the hard carbon material, and the inert atmosphere is at least one of nitrogen or argon.

[0012] In the second aspect, a petroleum coke (raw coke)-based hard carbon negative electrode material is prepared using the sodium ion battery petroleum coke (raw coke)-based hard carbon negative electrode material and its preparation method described in the first aspect.

[0013] In a third aspect, a negative electrode sheet for a sodium ion battery is provided.

[0014] It includes a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material as described in the second aspect.

[0015] A fourth aspect is a sodium ion secondary battery.

[0016] Includes the negative electrode sheet described in the third aspect.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) A sodium ion battery petroleum coke (green coke)-based hard carbon negative electrode material and its preparation method and application of the present invention, glucose and petroleum coke (green coke) are mixed in a certain mass ratio, and the mixture is pre-sintered under inert atmosphere conditions to obtain a pre-sintered powder, and the pre-sintered powder is carbonized at high temperature under inert atmosphere conditions to obtain a petroleum coke (green coke)-based hard carbon material; glucose is melted and infiltrated into the lattice spacing of petroleum coke (green coke) during the pre-sintering stage, and the glucose is prevented from further transforming into graphite at high temperature, thereby improving its ability to store sodium ions, thereby preparing a petroleum coke (green coke)-based hard carbon negative electrode material with excellent electrochemical properties;

[0019] (2) The present invention provides a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and its preparation method and application. The method is simple, low-cost, and can be used for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is the X-ray diffraction pattern (XRD) of the petroleum coke (raw coke) based hard carbon negative electrode material prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2.

[0021] Figure 2 This is a scanning electron microscope image (SEM) of the petroleum coke (green coke) based hard carbon negative electrode material prepared in Example 1.

[0022] Figure 3 This is a scanning electron microscope image (SEM) of the petroleum coke (raw coke) based hard carbon negative electrode material prepared in Example 2.

[0023] Figure 4 This is a scanning electron microscope image (SEM) of the petroleum coke (raw coke) based hard carbon negative electrode material prepared in Example 3.

[0024] Figure 5 This is a scanning electron microscope (SEM) image of the petroleum coke (raw coke) based hard carbon negative electrode material prepared in Comparative Example 1.

[0025] Figure 6 This is a scanning electron microscope (SEM) image of the petroleum coke (raw coke) based hard carbon negative electrode material prepared in Comparative Example 2.

[0026] Figure 7 It is a 0.2C cycle performance diagram of Example 1, Comparative Example 1 and Comparative Example 2 in a sodium ion battery.

[0027] Figure 8 It is a 0.2C cycle performance diagram of Example 2, Comparative Example 1 and Comparative Example 2 in a sodium ion battery.

[0028] Fig. 9 It is a 0.2C cycle performance diagram of Example 3, Comparative Example 1 and Comparative Example 2 in a sodium ion battery. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and its preparation method and application

[0032] The preparation steps are as follows: glucose and petroleum coke (green coke) are weighed in a mass ratio of 9:1 and then uniformly mixed; the resulting mixture is heated to 160°C in an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours to obtain a pre-sintered material; the pre-sintered material is heated to 1000°C in an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours to obtain a petroleum coke (green coke)-based hard carbon negative electrode material. The XRD spectrum of the prepared petroleum coke (green coke)-based hard carbon negative electrode material is shown in FIG. Figure 1 As shown, the appearance is Figure 2 shown.

[0033] Assembly and electrochemical performance test of button batteries:

[0034] The prepared petroleum coke (raw coke)-based hard carbon negative electrode material was mixed with Super P and PVDF in a mass ratio of 80:10:10, and an appropriate amount of N-methyl-2-pyrrolidone NMP was added to the mixed sample, stirred to form a uniform slurry, and the obtained slurry was coated on a copper foil, vacuum dried at 100°C for 12 hours, and cut to obtain a negative electrode sheet with a diameter of 11 mm; metallic sodium was used as the counter electrode, a glass fiber filter membrane (Whatman GF / C) was used as the diaphragm, a 1 mol / L NaPF6 solution of ethylene glycol dimethyl ether (DME) was used as the electrolyte, and a stainless steel shell was used as the shell to assemble a 2025 button battery; the charge and discharge test was completed under the Xinwei battery system, the test voltage range was 0.01-2.6V, the test temperature was room temperature, the test current density of the first 3 cycles was 0.1C (1C=300mA / g), and then the charge and discharge test was carried out for 50 cycles at a current density of 0.2C.

[0035] Experimental results: The first cycle discharge capacity is 330.92mAh / g, and the discharge capacity after 50 cycles is 151.98mAh / g ( Figure 7 ).

[0036] Example 2

[0037] This embodiment provides a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and its preparation method and application

[0038] The preparation steps are as follows: glucose and petroleum coke (green coke) are weighed in a mass ratio of 8:2 and then uniformly mixed, the resulting mixture is heated to 160°C under an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours, the pre-sintered material is heated to 1000°C under an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours to obtain a petroleum coke (green coke)-based hard carbon negative electrode material. The XRD spectrum of the prepared petroleum coke (green coke)-based hard carbon negative electrode material is shown in FIG. Figure 1 As shown, the appearance is Figure 3 shown.

[0039] As in Example 1, the electrodes were prepared, the battery was assembled, and electrochemical tests were performed.

[0040] Experimental results: The first cycle discharge capacity is 386.15mAh / g, and the discharge capacity after 50 cycles is 205.18mAh / g ( Figure 8 ).

[0041] Example 3

[0042] This embodiment provides a sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material and its preparation method and application

[0043] The preparation steps are as follows: glucose and petroleum coke (green coke) are weighed in a mass ratio of 7:3 and then uniformly mixed, the resulting mixture is heated to 160°C in an argon atmosphere at a heating rate of 3°C / min, and kept warm for 3 hours to obtain a pre-sintered material, and then heated to 1000°C in an argon atmosphere at a heating rate of 3°C / min and a holding time of 3 hours to obtain a petroleum coke (green coke)-based hard carbon negative electrode material. The XRD spectrum of the prepared petroleum coke (green coke)-based hard carbon negative electrode material is shown in Figure 1 As shown, the appearance is Figure 4 shown.

[0044] As in Example 1, the electrodes were prepared, the battery was assembled, and electrochemical tests were performed.

[0045] Experimental results: The first cycle discharge capacity is 402.77mAh / g, and the discharge capacity after 50 cycles is 190.12mAh / g ( Fig. 9 ).

[0046] Comparative Example 1

[0047] This comparative example provides biomass glucose-based hard carbon and its preparation method and application

[0048] The preparation steps are as follows: heating glucose to 160°C in an argon atmosphere at a heating rate of 3°C / min and keeping the temperature for 3 hours to obtain a pre-sintered material, and then heating it to 1000°C in an argon atmosphere at a heating rate of 3°C / min and keeping the temperature for 3 hours to obtain biomass glucose-based hard carbon. The XRD spectrum of the prepared biomass glucose-based hard carbon is shown in Figure 1 As shown, the appearance is Figure 5 shown.

[0049] As in Example 1, the electrodes were prepared, the battery was assembled, and electrochemical tests were performed.

[0050] Experimental results: The first cycle discharge capacity is 281.48 mAh / g, and the discharge capacity after 50 cycles is 67.96 mAh / g ( Figure 7-9 ).

[0051] Comparative Example 2

[0052] This comparative example provides a sodium ion battery petroleum coke (raw coke) based carbon negative electrode material and its preparation method and application

[0053] The preparation steps are as follows: petroleum coke (green coke) is heated to 160°C in an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours to obtain a pre-sintered material, and then heated to 1000°C in an argon atmosphere at a heating rate of 3°C / min and kept warm for 3 hours to obtain a petroleum coke (green coke)-based carbon negative electrode material. The XRD spectrum of the prepared petroleum coke (green coke)-based carbon is as follows: Figure 1 As shown, the appearance is Figure 6 shown.

[0054] As in Example 1, the electrode pieces were prepared, the battery was assembled, and the electrochemical test was performed.

[0055] Experimental results: The first cycle discharge capacity is 379.41mAh / g, and the discharge capacity after 50 cycles is 179.79mAh / g ( Figure 7-9 ).

Claims

1. A sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material, characterized in that: Glucose and petroleum coke (green coke) are used as carbon sources, mixed in a certain mass ratio, pre-sintered in an inert atmosphere and carbonized at high temperature to obtain a hard carbon material.

2. The sodium ion battery petroleum coke (raw coke) based hard carbon negative electrode material according to claim 1, characterized in that: The following steps are involved: Glucose and petroleum coke (raw coke) are mixed in a certain mass ratio, pre-sintered in an inert atmosphere, and carbonized at high temperature to obtain a hard carbon negative electrode material.

3. The preparation method according to claim 2, characterized in that: The mass ratio of glucose to petroleum coke (raw coke) is 9:1-1:9, preferably 9:1-5:

5.

4. The preparation method according to claim 2, characterized in that: The pre-sintering temperature under inert atmosphere is 150-700°C, preferably 160-400°C; the time is 1-10h, preferably 2-4h; the heating rate is 1-10°C / min, preferably 2-5°C / min; the inert atmosphere is at least one of nitrogen or argon.

5. The preparation method according to claim 2, characterized in that: The high-temperature carbonization temperature is 800-1500°C, preferably 900-1200°C; the carbonization time is 1-10h, preferably 2-4h; the heating rate is 1-10°C / min, preferably 2-5°C / min; and the inert atmosphere is at least one of nitrogen or argon.

6. Use of a sodium ion battery petroleum coke (green coke) based hard carbon negative electrode material as claimed in claim 1, or a petroleum coke (green coke) based hard carbon prepared by the method described in any one of claims 2 to 4 as a sodium ion battery negative electrode material.

7. A negative electrode plate for a sodium ion battery, comprising: A current collector, a binder coated on the current collector, a conductive agent and the petroleum coke (green coke) based hard carbon negative electrode material according to claim 1, or a sodium ion battery petroleum coke (green coke) based hard carbon negative electrode material prepared by the method described in any one of claims 2-4.

8. A sodium ion secondary battery comprising the negative electrode sheet of the sodium ion battery according to claim 6.

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