Preparation method of ethylene tar asphalt coated graphite material for potassium ion negative electrode material
Through the preparation method of ethylene tar asphalt coated graphite material, the problem of poor circulation and rate performance of the graphite anode material of potassium ion battery is solved, and the efficient preparation and performance of the material are achieved, which is suitable for potassium ion battery anode.
Patent Information
- Application Number
- CN202510795661.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-08-19
AI Technical Summary
The graphite anode material of potassium ion batteries is poor in terms of circulation and rate performance, and the existing coating methods are costly and take a long time to experiment, making it difficult to produce in large quantities.
Ethylene tar asphalt is used as the coating source, and ethylene tar asphalt is coated graphite material is prepared by ball milling, mixing, water bath stirring, drying and high-temperature treatment to improve the conductive properties and potassium storage ability of graphite materials.
The cyclic stability and rate performance of graphite materials are improved, and the capacity retention rate is between 61.5% and 78%, which is suitable for potassium ion battery negative electrode materials.
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Figure CN120504316A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of potassium ion battery negative electrode materials, and in particular relates to a method for preparing an ethylene tar pitch-coated graphite material for potassium ion negative electrode materials. Background Art
[0002] Potassium ion battery is an emerging secondary battery technology that mainly uses potassium ions (K + ) stores and releases energy during the intercalation and deintercalation processes between electrode materials. Compared with lithium-ion batteries, potassium-ion batteries have relatively abundant potassium resources, which makes them more sustainable and lower cost in terms of raw materials. However, potassium-ion batteries also have some challenges, such as lower electrochemical performance (especially energy density and cycle life). The research significance of potassium-ion batteries lies in that it provides the possibility for low-cost, high-resource-availability battery systems, especially in the field of large-scale energy storage, and has important application prospects. At present, the scientific community is actively studying how to achieve commercial applications through the electrochemical performance and stability of potassium-ion battery electrode materials. Among them, the development of graphite negative electrode materials with broad application prospects and low cost is the key to the development of potassium-ion batteries. Graphite anode materials for potassium-ion batteries have been studied, for example: He X, Zu X, Zhong L, et al. Carbon coating engineering enhances the stability of graphite anode in potassium-ion batteries [J]. Carbon, 2024, 230: 119588; Pan Q, Li B, Liu S, et al. Flower-like graphitic carbon derived from biomass for anode of potassium-ion battery [J]. Chemical Engineering Science, 2025, 304: 121043. However, due to the large radius of potassium ions, the diffusion energy barrier between graphite layers is high, resulting in low battery capacity. In addition, potassium ions cause significant expansion of the graphite material during charge and discharge, which can easily lead to structural damage and hinder its cyclic stability.
[0003] To address the above issues, several improvement methods have been proposed: first, by coating the surface of graphite with other materials to enhance the insertion / extraction performance of potassium ions; second, by using composite materials, such as combining graphite with conductive polymers, metal oxides, or carbon nanotubes, to enhance the structural stability and electrical conductivity of graphite; third, by developing new negative electrode materials, such as conductive carbon-based materials or alloy materials, to replace graphite to better adapt to the chemical properties of potassium ions, thereby improving the overall performance of the battery. Among them, surface coating has the advantages of low cost, simple preparation methods, and a wide range of raw material sources. Therefore, surface coating is the focus of research on improving graphite negative electrode materials.
[0004] Selecting the right coating source is a key research topic. Recent studies have shown that coating the surface of graphite with soft carbon materials that exhibit good conductivity and large interlayer spacing can effectively improve the conductivity and interlayer spacing of graphite, thereby enhancing the cycling stability and potassium storage capacity of graphite at high rates. However, previous literature has required complex experimental methods during the precursor preparation stage, resulting in high material costs, lengthy experiments, and demanding preparation conditions, making mass production difficult. Summary of the Invention
[0005] To overcome the deficiencies of the prior art, the present invention aims to provide a method for preparing an ethylene tar pitch-coated graphite material for potassium ion negative electrode materials, thereby solving the problem of poor cycle / rate performance when graphite material alone is used as the negative electrode material for potassium ion batteries.
[0006] To achieve the above object, the present invention is implemented through the following technical solutions:
[0007] A method for preparing an ethylene tar pitch coated graphite material for a potassium ion negative electrode material comprises the following steps:
[0008] 1) ball milling the graphite material and sieving to obtain a graphite material with a uniform particle size of 200 to 300 meshes;
[0009] 2) heating the graphite material obtained in step 1) at a constant temperature of 300-500° C. for 1.5-2.5 hours, and cooling it to room temperature to obtain a treated graphite material;
[0010] 3) mixing the ethylene tar pitch material and the graphite material obtained in step 2) in ethylene glycol to obtain a mixed solution;
[0011] 4) Place the mixed solution in a water bath at 40-60°C, stir for 8-15 hours, and then transfer to the reactor;
[0012] 5) The reactor was placed in a forced air drying oven at a constant temperature of 150-200° C. for 8-12 hours, then cooled to room temperature, taken out and filtered, repeatedly rinsed with deionized water and dried to obtain a precursor material;
[0013] 6) placing the precursor material in a tube furnace, maintaining a constant temperature of 800-1400° C. for 1-3 hours under an inert atmosphere, and then cooling to room temperature to obtain an ethylene tar pitch-based material coated graphite material.
[0014] The graphite material described in step 2) is placed in a tubular furnace for heating.
[0015] The atmosphere in the tube furnace is oxygen or air.
[0016] In step 3), 1 to 2 g of graphite material is taken, and 20% to 60% of ethylene tar pitch material is weighed relative to the mass fraction of the graphite material, and the two are mixed in 60 to 80 mL of ethylene glycol to obtain a mixed solution.
[0017] The ethylene tar pitch material described in step 3) has a softening point of 140-280° C. and a coking value of 40%-60%.
[0018] The ethylene tar pitch material is ethylene tar pitch or water-soluble ethylene tar pitch.
[0019] The inert atmosphere in step 6) is nitrogen or argon atmosphere.
[0020] The graphite material in step 1) is artificial graphite and / or natural graphite.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The present invention uses ethylene tar pitch as a coating source to coat the graphite material. Since ethylene tar pitch has the properties of soft carbon, coating it on the surface of the graphite material can effectively improve the electrical conductivity of the material, and the more defects of the soft carbon material will also provide more potassium storage sites for the graphite material, which can effectively improve the cycle rate performance of the graphite material. The prepared ethylene tar pitch hard carbon material is applied to the negative electrode material of the potassium ion half-cell. The optimal potassium storage capacity is 288mAh / g at a current density of 0.1A / g. After 100 cycles, the capacity is 172.1~224.1mAh / g, and the capacity retention rate is 61.5%~78%, which shows that the ethylene tar pitch coated graphite material has considerable application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 This is a flow chart for the preparation of ethylene tar pitch coated graphite material.
[0024] Figure 21 is the XRD pattern of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example.
[0025] Figure 3 It is the Raman graph of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example.
[0026] Figure 4 These are SEM images of the ethylene tar pitch coated graphite materials prepared in Examples 1 to 5 and the comparative example.
[0027] Figure 5 This is the FT-IR test result of the material before and after coating.
[0028] Figure 6 This is the XPS graph of the material before and after coating.
[0029] Figure 7 (a) is a nitrogen adsorption / desorption curve diagram of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example; (b) is a pore size distribution diagram of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example.
[0030] Figure 8 3 is a cycle performance diagram of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example.
[0031] Figure 9 3 is a rate performance diagram of the ethylene tar pitch coated graphite material prepared in Examples 1 to 5 and the comparative example. DETAILED DESCRIPTION
[0032] The present invention will be described in detail below with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.
[0033] Example 1
[0034] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0035] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0036] 2) The graphite material obtained in step 1) (please provide the mass value; in subsequent examples, it is also best to provide the specific grams) is placed in a tube furnace, maintained at 400° C. for 2 hours under an air atmosphere, and cooled to room temperature to obtain a treated graphite material;
[0037] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 20% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0038] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0039] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0040] 6) The precursor material obtained by drying in step 5) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material, named HG@20%-1000.
[0041] Example 2
[0042] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0043] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0044] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0045] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 30% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0046] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0047] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0048] 6) The precursor material obtained by drying in step 5) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material, named HG@30%-1000.
[0049] Example 3
[0050] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0051] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0052] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0053] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 40% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0054] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0055] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0056] 6) The precursor material obtained by drying in step 5) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material, named HG@40%-1000.
[0057] Example 4
[0058] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0059] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0060] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0061] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0062] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0063] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0064] 6) The precursor material obtained by drying in step 5) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material, named HG@50%-1000.
[0065] Example 5
[0066] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0067] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0068] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0069] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 60% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0070] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0071] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0072] 6) The precursor material obtained by drying in step 5) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material, named HG@60%-1000.
[0073] Example 6
[0074] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0075] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0076] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0077] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0078] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0079] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0080] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at 800° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0081] Example 7
[0082] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0083] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0084] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0085] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0086] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0087] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0088] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1200° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0089] Example 8
[0090] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0091] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0092] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0093] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0094] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0095] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0096] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1400° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0097] Example 9
[0098] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0099] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0100] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0101] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 160°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0102] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0103] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0104] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0105] Example 10
[0106] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0107] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0108] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0109] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 200°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0110] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0111] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0112] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0113] Example 11
[0114] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0115] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0116] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0117] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 280°C, coking value 40%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0118] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0119] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0120] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0121] Example 12
[0122] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0123] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0124] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0125] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 160°C, coking value 60%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0126] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0127] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0128] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0129] Example 13
[0130] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0131] 1) ball milling the untreated graphite material, and then passing it through a 150-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0132] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0133] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0134] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0135] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0136] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0137] Example 14
[0138] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0139] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0140] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an oxygen atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0141] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 70 mL of ethylene glycol to obtain a mixed solution;
[0142] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0143] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0144] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0145] Example 15
[0146] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0147] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0148] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 450° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0149] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 60 mL of ethylene glycol to obtain a mixed solution;
[0150] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0151] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0152] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0153] Example 16
[0154] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0155] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0156] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 1.5 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0157] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0158] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0159] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0160] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0161] Example 17
[0162] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0163] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0164] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0165] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0166] 4) The mixed solution in step 3) was placed in a 40°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0167] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0168] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0169] Example 18
[0170] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0171] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0172] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0173] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0174] 4) The mixed solution in step 3) was placed in a water bath at 60° C., stirred for 12 h, and then transferred to a reactor;
[0175] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0176] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0177] Example 19
[0178] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0179] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0180] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0181] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0182] 4) The mixed solution in step 3) was placed in a water bath at 50° C., stirred for 8 h, and then transferred to a reactor;
[0183] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0184] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0185] Example 20
[0186] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0187] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0188] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0189] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0190] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 14 hours, and then transferred to a reactor;
[0191] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 10 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0192] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0193] Example 21
[0194] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0195] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0196] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0197] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0198] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0199] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 150° C. for 10 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0200] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0201] Example 22
[0202] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0203] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0204] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0205] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0206] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0207] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 200° C. for 10 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0208] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0209] Example 23
[0210] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0211] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0212] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0213] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0214] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0215] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 8 h, then cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0216] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0217] Example 24
[0218] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0219] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0220] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0221] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0222] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0223] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 12 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0224] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under a nitrogen atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0225] Example 25
[0226] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0227] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0228] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0229] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0230] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0231] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 12 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0232] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 1 hour under a nitrogen atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0233] Example 26
[0234] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0235] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0236] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0237] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0238] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0239] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 12 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0240] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 3 hours under a nitrogen atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0241] Example 27
[0242] See Figure 1 A method for preparing an ethylene tar pitch coated graphite material comprises the following steps:
[0243] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0244] 2) placing the graphite material obtained in step 1) in a tube furnace, maintaining a constant temperature at 400° C. for 2 hours under an air atmosphere, and cooling to room temperature to obtain a treated graphite material;
[0245] 3) Weighing 1 g of the graphite material prepared in step 2) and then weighing 50% by mass of water-soluble ethylene tar pitch (softening point 240°C, coking value 50%) relative to the graphite material, and placing the two in 80 mL of ethylene glycol to obtain a mixed solution;
[0246] 4) The mixed solution in step 3) was placed in a 50°C water bath, stirred for 12 hours, and then transferred to a reactor;
[0247] 5) The reactor in step 4) was placed in a forced air drying oven at a constant temperature of 180° C. for 12 h, cooled to room temperature, taken out and filtered, rinsed repeatedly with deionized water and dried.
[0248] 6) The precursor material obtained by drying in step 5) is placed in a tube furnace, kept at a constant temperature of 1000° C. for 3 hours under a nitrogen atmosphere, and then cooled to room temperature to obtain an ethylene tar pitch coated graphite material.
[0249] Comparative Example
[0250] 1) ball milling the untreated graphite material, and then passing it through a 200-mesh sieve to obtain a graphite material with a small and uniform particle size;
[0251] 2) The graphite material obtained in step 1) was placed in a tube furnace, kept at a constant temperature of 1000° C. for 2 hours under an argon atmosphere, and cooled to room temperature to obtain a carbonized graphite material as a comparison material.
[0252] The prepared samples were made into electrode sheets, which were assembled into button batteries in the order of negative electrode shell, potassium sheet, diaphragm, negative electrode sheet, gasket, spring sheet, and positive electrode shell to test the electrochemical performance.
[0253] Depend on Figure 2 As can be seen, the two broad diffraction peaks at around 24° and 43° correspond to the (002) and (100) crystal planes. It is clear that the interlayer spacing of the coated material is slightly larger than that of the uncoated material. This is because the interlayer spacing of the carbonized ethylene tar pitch is larger than that of graphite, which causes the interlayer spacing of the coated material to slightly decrease with increasing coating amount. Furthermore, the intensity of the (002) characteristic peak of the coated material is significantly lower than that of the uncoated material, indicating that the degree of graphitization of the coated material gradually decreases.
[0254] See Figure 3 , by calculating the intensity ratio of G peak to D peak, that is, I G / I D It can more intuitively show the degree of graphitization of the material. G / I D The higher the value, the higher the graphitization degree of the material. After calculation, it can be seen that the graphitization degree of the coated material is lower than that of the uncoated material, and with the increase of the coating amount, the graphitization degree of the material gradually decreases, which is consistent with the analysis in XRD.
[0255] See Figure 4 Because ethylene tar pitch has a softening point of 240°C and has high viscosity and good wettability with carbon materials, it easily forms a coating on the surface of the carbon material during the carbonization process. It can be seen that the surface of the coated materials clearly exhibits varying degrees of layered structures, and the particle size of all materials has increased compared to the Graphite-1000 material, indicating that the ethylene tar pitch has been successfully coated on the surface of the graphite material.
[0256] See Figure 5 Since the aromatic rings of ethylene tar pitch begin to stack after carbonization at 1000℃, a graphite-like structure is formed, but the aromatic ring skeleton is still retained. Therefore, it can be clearly seen in the figure that the 611cm -1The vibration of the CH peak on the aromatic ring at 3450cm is detected, and its peak intensity increases with the increase of the ethylene tar pitch coating amount. In addition, with the increase of the ethylene tar pitch coating amount, the material -1 -OH vibration at 1730cm -1 C=O vibration at 1100 cm -1 The CO vibration peak intensity at gradually increases, which indicates that with the increase of ethylene tar pitch coating amount, the proportion of oxygen-containing functional groups in the material gradually increases. Figure 5 As can be seen, the specific surface area and pore volume of the material gradually decrease with increasing ethylene tar addition. This is likely because the ethylene tar pitch initially enters the material's pores, blocking them and reducing their specific surface area and pore volume. When the coating amount increases to 50%, the ethylene tar pitch completely coats the material surface. Therefore, when the coating amount is 50%, the HG@50%-1000 material has the largest specific surface area.
[0257] See Figure 6 , after 100 cycles, the potassium storage capacity of all materials is 172.1mAh / g, 181.3mAh / g, 212.6mAh / g, 224.1mAh / g, 201.9mAh / g and 207.5mAh / g in the above order, and the capacity retention rates are 61.5%, 64.7%, 71.2%, 78%, 71.8% and 68.2% respectively. It can be seen that when the ethylene tar pitch coating reaches 40%, the cycle stability of the material begins to improve. Among them, the @50%-1000 material has the highest potassium storage capacity and the best cycle stability after 100 cycles. This is due to the fact that the @50%-1000 material has a larger interlayer spacing, which provides a larger transmission path for potassium ions, which can effectively reduce the diffusion energy barrier of potassium ions during the charge and discharge process, thereby improving the cycle stability of the material. In addition, from Figure 6 It can be seen that the O1s peak intensity of the material coated with ethylene tar pitch increases, which indicates that its oxygen content increases. Figure 5 The analysis is consistent.
[0258] See Figure 7From the rate performance diagrams of the materials of Examples 1-5 and the comparative example at current densities of 0.05A / g, 0.1A / g, 0.2A / g, 0.3A / g, 0.5A / g, and 1A / g, it can be seen that the potassium storage capacity of the uncoated -1000 graphite material in the comparative example is 259.1mAh / g, 244.2mAh / g, 220.5mAh / g, 116.9mAh / g, 83.6mAh / g, and 23mAh / g, respectively, which indicates that when the current density exceeds 0.2A / g, the potassium storage capacity of the -1000 material is significantly reduced. This is because its smaller interlayer spacing causes the volume of the material to expand rapidly during the rapid deintercalation of potassium ions, resulting in drastic structural changes. Therefore, the material has poor potassium storage kinetics and cannot support its rapid charge and discharge. When the coating amount is less than 40% at a higher current density, the potassium storage capacity of the material is still low. However, when the coating amount reaches and exceeds 40%, the potassium storage capacity of the material at a higher current density is significantly improved. Among them, the @50%-1000 material has the best rate performance, with potassium storage capacities of 310.3mAh / g, 273.5mAh / g, 249.7mAh / g, 230.6mAh / g, 168.6mAh / g, and 91.2mAh / g, respectively, and the current density returns to 0.1A. -1 The latter material can still provide 267mAh g -1 This shows that an appropriate coating amount can support the rapid charging and discharging of potassium ions, thereby improving the potassium storage kinetics of the material and improving the rate performance of the material.
[0259] The ethylene tar pitch coated graphite material prepared in each example is applied to the negative electrode material of the potassium ion half-cell. The capacity and capacity retention after 100 cycles at a current density of 1 A / g are shown in Table 1.
[0260] Table 1
[0261]
[0262]
[0263] The above electrochemical experimental results show that the ethylene tar pitch was selected as the coating source to coat the graphite material and prepare the ethylene tar pitch coated graphite material. The coated material effectively increases the interlayer spacing of the material and accelerates the diffusion rate of potassium ions, thereby improving its electrochemical cycle rate performance. Among them, the best performance material is at 0.1Ag -1 The potassium storage capacity is 277.1 mAh g -1 After 100 cycles, the potassium storage capacity is 224.1 mAh g -1, with a capacity retention rate of 78%. In summary, coating graphite with ethylene tar pitch can effectively increase the interlayer spacing and conductivity of the material, reduce the diffusion barrier of potassium ions, and effectively improve the potassium storage kinetics of the material, thereby significantly improving the cycle stability and rate performance, and proposing a new direction for the large-scale production of low-cost, high-performance potassium ion battery anode materials.
Claims
1. A method for preparing an ethylene tar pitch coated graphite material for potassium ion negative electrode material, characterized in that: The following steps are involved: 1) ball milling the graphite material and sieving to obtain a graphite material with a uniform particle size of 200 to 300 meshes; 2) heating the graphite material obtained in step 1) at a constant temperature of 300-500° C. for 1.5-2.5 hours, and cooling it to room temperature to obtain a treated graphite material; 3) mixing the ethylene tar pitch material and the graphite material obtained in step 2) in ethylene glycol to obtain a mixed solution; 4) Place the mixed solution in a water bath at 40-60°C, stir for 8-15 hours, and then transfer to the reactor; 5) The reactor was placed in a forced air drying oven at a constant temperature of 150-200° C. for 8-12 hours, then cooled to room temperature, taken out and filtered, repeatedly rinsed with deionized water and dried to obtain a precursor material; 6) placing the precursor material in a tube furnace, maintaining a constant temperature of 800-1400° C. for 1-3 hours under an inert atmosphere, and then cooling to room temperature to obtain an ethylene tar pitch-based material coated graphite material.
2. The method for preparing an ethylene tar pitch coated graphite material for a potassium ion negative electrode material according to claim 1, wherein: The graphite material described in step 2) is placed in a tubular furnace for heating.
3. The method for preparing an ethylene tar pitch coated graphite material for a potassium ion negative electrode material according to claim 2, wherein: The atmosphere in the tube furnace is oxygen or air.
4. The method for preparing an ethylene tar pitch coated graphite material for a potassium ion negative electrode material according to claim 1, wherein: In step 3), 1 to 2 g of graphite material is taken, and 20% to 60% of ethylene tar pitch material is weighed relative to the mass fraction of the graphite material, and the two are mixed in 60 to 80 mL of ethylene glycol to obtain a mixed solution.
5. The method for preparing an ethylene tar pitch coated graphite material for potassium ion negative electrode material according to claim 1, characterized in that: The ethylene tar pitch material described in step 3) has a softening point of 140-280° C. and a coking value of 40%-60%.
6. The method for preparing an ethylene tar pitch coated graphite material for potassium ion negative electrode material according to claim 1, characterized in that: The ethylene tar pitch material is ethylene tar pitch or water-soluble ethylene tar pitch.
7. The method for preparing an ethylene tar pitch coated graphite material for potassium ion negative electrode material according to claim 1, characterized in that: The inert atmosphere in step 6) is nitrogen or argon atmosphere.
8. The method for preparing an ethylene tar pitch coated graphite material for potassium ion negative electrode material according to claim 1, characterized in that: The graphite material in step 1) is artificial graphite and / or natural graphite.