Preparation method of potassium ion battery positive electrode material

Abstract

The invention provides a preparation method of a potassium ion battery positive electrode material, which comprises the following steps: S1, adding 25ml of concentrated hydrochloric acid into 75ml of deionized water, and stirring and mixing with a glass rod to obtain a cleaning solution; s2, putting the cut 1 * 1cm titanium mesh into a beaker, performing ultrasonic cleaning by using a cleaning solution, ethanol and deionized water in sequence, and then putting the beaker into a vacuum drying oven to be dried at 60 DEG C for 8 hours; and S3, the cleaned titanium mesh is immersed in the surface agent dispersion liquid. According to the preparation method of the positive electrode material of the potassium ion battery, provided by the invention, a primary oxidation film and oil stain impurities on the surface of a titanium mesh can be effectively removed through a precise cleaning process; meanwhile, graphite is introduced as a surface agent, after nitrogen protection calcination, a uniform Ti (X) conductive substrate is formed on the surface of the titanium mesh, direct contact between the titanium mesh and an electrolyte can be thoroughly isolated through high conductivity of the graphite, generation of a new oxide film is avoided, meanwhile, an efficient electron transmission channel is constructed, charge transfer impedance is effectively reduced, and the conductivity of the titanium mesh is improved. The core problem that an oxidation film hinders electron transmission is solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrochemical energy storage devices, in particular to a preparation method of a positive electrode material of a potassium ion battery. BACKGROUND

[0002] At present, with the continuous growth of global energy demand and the deep integration of sustainable development concepts, large-scale energy storage technology has become a key link to promote the transformation of energy structure. Aqueous potassium ion battery, with the advantages of rich potassium resource reserves, low cost, high safety and environmental friendliness, has shown great application potential in large-scale energy storage fields such as smart grid peak shaving and renewable energy grid connection, and has become one of the important candidate technologies to replace traditional lithium ion batteries.

[0003] As the positive electrode material of the aqueous potassium ion battery, layered manganese dioxide is widely considered to be a promising energy storage material due to its high theoretical specific capacity, abundant resource reserves and good environmental compatibility. Current research shows that layered manganese dioxide can be simply prepared by potassium permanganate hydrothermal reaction under suitable temperature and pressure conditions, which provides a basic condition for its practical application. However, traditional electrode preparation processes, such as grinding and coating method, usually require the use of polymer adhesives to fix the active material on the conductive substrate to ensure the stability of the electrode structure. However, this method has obvious drawbacks. The adhesives will form an insulating layer between the active material and the conductive substrate, resulting in increased contact resistance and reduced electron transport efficiency, which ultimately seriously affects the electrochemical performance of the electrode. To overcome this defect, adhesive-free electrode preparation technology has gradually become a research hotspot. Among them, the process of in-situ growth of layered MnO2 on the conductive substrate by hydrothermal method is widely explored. Existing researches mostly use foam nickel, carbon cloth or carbon nanotubes as the conductive substrate. In the aqueous electrolyte system, titanium metal is an ideal substrate material due to its high conductivity, chemical inertness and mechanical strength. For example, Liu et al. achieved effective compounding of Ti substrate and MnO2 by sodium hydroxide etching pretreatment process, and confirmed that the composite material has application potential in electrochemical energy storage. Although the in-situ growth process without adhesives optimizes the electrode performance to a certain extent, the existing technology still faces key problems when directly growing layered manganese dioxide on the titanium mesh by in-situ hydrothermal method to prepare adhesive-free Ti@MnO2 electrode. The titanium mesh surface is prone to form an oxide film.

[0004] This oxide film will increase the charge transfer impedance between the substrate and the active material and the electrolyte, hinder electron transport and interfacial electrochemical reaction, and thus seriously limit the electrochemical performance of the electrode. The cycle stability also needs to be improved. With the increasing demand for positive electrode performance, the modification scheme of the positive electrode material is becoming increasingly complex. Although the introduction of complex structure design and low-dimensional materials can increase the potassium storage capacity of the positive electrode material, the huge production cost seriously hinders the commercialization process.

[0005] Therefore, it is necessary to provide a preparation method of a potassium ion battery positive electrode material to solve the above technical problems. SUMMARY

[0006] The application provides a preparation method of a potassium ion battery positive electrode material, which solves the problems of large charge transfer impedance and blocked electron transmission caused by the oxide film, and the problems of complex modification scheme and high cost.

[0007] To solve the above technical problems, the application provides a preparation method of a potassium ion battery positive electrode material, which comprises the following steps: S1, 25ml of concentrated hydrochloric acid is added to 75ml of deionized water, and a glass rod is used to stir and mix to obtain a cleaning solution; S2, the cut 1*1cm titanium mesh is placed in a beaker, and is sequentially ultrasonically cleaned with the cleaning solution, ethanol and deionized water, and is then placed in a vacuum drying box and dried at 60 DEG C for 8h; S3, the cleaned titanium mesh is immersed in a surface agent dispersion liquid, and the surface agent is adsorbed on the surface of the titanium mesh through the surface tension of the surface agent, and the titanium mesh after adsorbing the surface agent is transferred to a 60 DEG C oven for 2h baking to remove the adsorbed water; S4, the dried titanium mesh with the adsorbed surface agent is further treated to obtain a Ti@X conductive substrate; S5, 0.158g of potassium permanganate is added to 60ml of deionized water, and a glass rod is used to stir until the solute is completely dissolved, and the solution is all transferred to a 100ml constant volume bottle, and deionized water is used to constant volume to 100ml, to obtain a purple precursor solution; S6, 0.2ml of 1M H2SO4 is added to the 60ml precursor solution; S7, the mixed solution of step S6 is placed in a 100ml polytetrafluoroethylene tank, and the Ti@X substrate is placed in the tank and transferred to a stainless steel autoclave for reaction at 200 DEG C for 30min; S8, the reacted pole piece is washed with deionized water and ethanol alternately for 3 times, and finally the pole piece is vacuum dried at 60 DEG C for 6 hours to obtain a binder-free Ti@X@MnO2 electrode; S9, in the preparation of the Ti@MnO2 electrode, the Ti@X substrate in the above step is replaced by a titanium mesh, and the rest of the conditions remain unchanged, and finally a Ti@MnO2 composite electrode is obtained.

[0008] Preferably, in step 3, the surface agent is graphite, and the amount of the surface agent is 100mg, and the amount of deionized water is 50ml.

[0009] Preferably, in step 4, the further treatment is high-temperature calcination, and the calcination conditions are 350 DEG C for 2 hours, and the heating rate is 2 DEG C / min.

[0010] Preferably, in step 7, the Ti@X substrate is placed vertically in the tank.

[0011] Preferably, in step S5, the potassium permanganate has an analytical purity (AR grade), and an electronic balance with an accuracy of 0.1 mg is used during the weighing process to ensure that the weighing error is ≤±0.5 mg.

[0012] Preferably, in step S7, the polytetrafluoroethylene tank is cleaned with concentrated nitric acid (65%) and deionized water for 15 minutes each before being dried in an oven at 120°C for 2 hours to ensure that there is no organic residue or moisture on the surface of the tank.

[0013] Preferably, in step S8, the deionized water used during the flushing process has a conductivity of ≤10 μS / cm, the ethanol is anhydrous ethanol (purity ≥99.7%), and the electrode piece is completely immersed and ultrasonically treated for 5 minutes each time.

[0014] Preferably, in step S9, the replacement operation is performed in a dust-free glove box (humidity ≤5%, oxygen content ≤1 ppm), and the titanium mesh is wiped with acetone before replacement.

[0015] Preferably, in step S3, the preparation temperature of the surface agent dispersion liquid is 25±2°C, and a magnetic stirrer is used to stir at a speed of 300 r / min for 30 minutes to ensure uniform dispersion of the graphite surface agent in deionized water.

[0016] Preferably, in step S4, the high-temperature calcination is performed in a nitrogen (purity ≥99.99%) protective atmosphere, and nitrogen is introduced at a flow rate of 50 mL / min during the heating process. After calcination, the sample is removed after the furnace cools to room temperature.

[0017] Compared with the related art, the preparation method of the positive electrode material of the potassium ion battery has the following beneficial effects: The preparation method of the positive electrode material of the potassium ion battery provided by the application can effectively remove the native oxide film and oil impurities on the surface of the titanium mesh through a precise cleaning process. Meanwhile, graphite is introduced as a surface agent, and a uniform Ti@X conductive substrate is formed on the surface of the titanium mesh after nitrogen protection calcination. The high conductivity of the graphite can completely isolate the titanium mesh from direct contact with the electrolyte, avoid the generation of new oxide films, and construct an efficient electron transmission channel, effectively reducing the charge transfer impedance and solving the core problem of the oxide film hindering electron transmission. The method does not need complex structure design or expensive materials, and only through a simple process of cleaning, graphite surface modification and hydrothermal growth, the performance can be improved: the graphite surface agent is widely available and low in cost; the hydrothermal reaction condition is mild, without high temperature and high pressure or special equipment; and no polymer adhesive is used throughout, which not only reduces the material cost, but also avoids the insulation problem caused by the adhesive, and is suitable for commercial application process. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 SEM images of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application; Figure 2 The cycle performance of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application at 5 Ag -1 Current density is compared with the cycle performance of the traditional coated Ti / binder / KMO electrode; Figure 3 The rate performance comparison chart of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application and the traditional coated Ti / binder / KMO electrode; Figure 4 The AC impedance comparison chart of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application and the traditional coated Ti / binder / KMO electrode. DETAILED DESCRIPTION

[0019] The application will be further described below in combination with the drawings and embodiments.

[0020] Example 1 Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 Among them, Figure 1 SEM images of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application; Figure 2 The cycle performance of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application at 5 Ag -1 Current density is compared with the cycle performance of the traditional coated Ti / binder / KMO electrode; Figure 3 The rate performance comparison chart of the Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrodes prepared by the hydrothermal method provided by the application and the traditional coated Ti / binder / KMO electrode; Figure 4The application provides a Ti@X@MnO2 and Ti@MnO2 potassium ion battery electrode prepared based on a hydrothermal method and a traditional Ti / binder / KMO electrode alternating current impedance comparison chart.

[0021] A preparation method of a potassium ion battery positive electrode material, comprising the following steps: S1, 25ml of concentrated hydrochloric acid is added into 75ml of deionized water, and a glass rod is used to stir and mix to obtain a cleaning solution; S2, the cut 1*1cm titanium mesh is placed in a beaker, and is sequentially ultrasonically cleaned with the cleaning solution, ethanol and deionized water, and then is placed in a vacuum drying box and dried at 60 DEG C for 8h; S3, the cleaned titanium mesh is immersed into a surface agent dispersion liquid, the surface agent is adsorbed on the surface of the titanium mesh through the surface tension of the surface agent, and the titanium mesh after adsorbing the surface agent is transferred to a 60 DEG C oven for 2h baking to remove the adsorbed water; S4, the dried titanium mesh after adsorbing the surface agent is further treated to obtain a Ti@X conductive substrate; S5, 0.158g of potassium permanganate is added into 60ml of deionized water, and a glass rod is used to stir until the solute is completely dissolved, the solution is all transferred into a 100ml constant volume bottle, and deionized water is used to constant volume to 100ml, and a purple precursor solution is obtained; S6, 0.2ml of 1M H2SO4 is added into the 60ml precursor solution; S7, the mixed solution of step S6 is placed in a 100ml polytetrafluoroethylene tank body, the Ti@X substrate is placed in the tank body and is transferred to a stainless steel autoclave for reaction at 200 DEG C for 30min; S8, the pole piece after reaction is washed with deionized water and ethanol alternately for 3 times, finally the pole piece is vacuum dried at 60 DEG C for 6 hours, and a binder-free Ti@X@MnO2 electrode is obtained; S9, in the preparation of the Ti@MnO2 electrode, the Ti@X substrate in the above step is replaced by a titanium mesh, and the rest conditions are unchanged, and finally a Ti@MnO2 composite electrode is obtained.

[0022] In step 3, the surface agent is graphite, and the amount of the surface agent is 100mg, and the deionized water is 50ml.

[0023] In step 4, the further treatment is high-temperature calcination, the calcination condition is 350 DEG C for 2 hours, and the temperature rising rate is 2 DEG C / min.

[0024] In step 7, the Ti@X substrate is placed in the tank body, and the placing mode is vertical placement.

[0025] In the step S5, the purity of potassium permanganate is analytical reagent (AR grade), and an electronic balance with an accuracy of 0.1 mg is used in the weighing process to ensure that the weighing error is ≤±0.5 mg.

[0026] In the step S7, the polytetrafluoroethylene tank is sequentially cleaned with concentrated nitric acid (65%) and deionized water for 15 minutes each under ultrasonic, and then dried in an oven at 120°C for 2 hours to ensure that there is no organic residue and moisture on the surface of the tank.

[0027] In the step S8, the conductivity of the deionized water used in the flushing process is ≤10 μS / cm, the ethanol is anhydrous ethanol (purity ≥99.7%), and the electrode plate needs to be completely immersed and ultrasonically treated for 5 minutes each time.

[0028] In the step S9, the replacement operation needs to be carried out in a dust-free glove box (humidity ≤5%, oxygen content ≤1 ppm), and the titanium mesh needs to be wiped with acetone before replacement to remove surface grease.

[0029] In the step S3, the preparation temperature of the surface agent dispersion liquid is 25±2°C, and a magnetic stirrer is used to stir at a speed of 300 r / min for 30 minutes to make the graphite surface agent uniformly dispersed in deionized water.

[0030] In the step S4, high-temperature calcination needs to be carried out in a nitrogen (purity ≥99.99%) protective atmosphere, and nitrogen is passed at a flow rate of 50 mL / min during the heating process. After calcination, the sample is taken out after the furnace is cooled to room temperature.

[0031] Through the hydrothermal in-situ growth process of steps S7-S8, the MnO2 active material is directly attached to the surface of the Ti@X conductive substrate to form a binder-free Ti@X@MnO2 electrode. On the one hand, the interface bonding force between the substrate and the active material is stronger, avoiding the shedding of the active material during the cycle process. On the other hand, the binder-free structure can increase the contact area of the active material and the electrolyte, improve the ion diffusion efficiency, and the Ti@X@MnO2 electrode still maintains a high capacity at a high rate (such as 10 A / g), which proves that it has excellent large-current charging and discharging capacity, fully meeting the demand for electrode stability and high power performance in large-scale energy storage scenarios such as smart grid peak shaving and renewable energy grid connection; The process is precisely controllable, ensuring product consistency and facilitating large-scale production. This method strictly controls the parameters of key steps (such as the weighing error of potassium permanganate in S5 ≤±0.5 mg, the preparation temperature of the surface agent dispersion liquid in S3 25±2°C, and the pretreatment process of the polytetrafluoroethylene tank in S7), ensuring that the performance of each batch of electrodes is stable and consistent. For example, in S5, 0.1 mg precision electronic balance is used to weigh potassium permanganate, and 100 ml constant volume operation is matched to accurately control the precursor concentration; in S7, the vertical placement of the substrate can ensure the uniform growth of MnO2 on the substrate surface; this standardized and reproducible process design avoids human errors in traditional manual coating method, lays a foundation for subsequent large-scale production, and further solves the problem of batch production of high-performance electrodes in the prior art.

[0032] The working principle of the preparation method of the positive electrode material of the potassium ion battery provided by the application is as follows: Cleaning the titanium mesh: a cleaning solution is prepared by mixing concentrated hydrochloric acid and deionized water in a certain proportion, and the titanium mesh is ultrasonically cleaned, which can effectively remove the original oxide film and oil stains on the surface of the titanium mesh, providing a clean substrate for subsequent processing; Surface agent adsorption and treatment: after cleaning, the titanium mesh is immersed in a dispersion liquid with graphite as a surface agent, and the surface tension of the surface agent is used to make it adsorb on the surface of the titanium mesh; then, baking is performed to remove adsorbed water, and then high-temperature calcination (in a nitrogen protective atmosphere, 350℃ for 2 hours, with a heating rate of 2℃ / min) is performed, to form a uniform Ti@X conductive substrate on the surface of the titanium mesh; the high conductivity of graphite can isolate the titanium mesh from direct contact with the electrolyte, avoid the generation of new oxide film, and at the same time, build an efficient electron transmission channel; Preparation of precursor solution: accurately weigh the analytically pure potassium permanganate, dissolve it in deionized water and constant volume, to obtain a purple precursor solution, and then add sulfuric acid for adjustment, to provide a suitable solution environment for subsequent hydrothermal reaction; Hydrothermal reaction to grow MnO2: the mixed solution is placed in a polytetrafluoroethylene tank, the Ti@X substrate is vertically placed, and then the high-pressure kettle is placed in the tank, and the reaction is carried out at 200℃ for 30min, to make the MnO2 grow in situ on the Ti@X substrate, to form a Ti@X@MnO2 electrode without binder; Preparation of comparative electrode: replace the Ti@X substrate with a titanium mesh, and other conditions remain unchanged, to prepare a Ti@MnO2 composite electrode, which is used for performance comparison with the Ti@X@MnO2 electrode; Performance improvement principle: the graphite in the Ti@X conductive substrate isolates the titanium mesh from the electrolyte, prevents the generation of oxide film, reduces the charge transfer impedance, and optimizes the electron transmission; the binder-free design avoids the formation of an insulating layer by the adhesive, reduces the contact resistance, improves the electron transmission efficiency, and thus improves the electrochemical performance of the electrode.

[0033] Compared with related technologies, the preparation method of the positive electrode material of the potassium ion battery provided by the application has the following beneficial effects: Through the precise cleaning process, the original oxide film and oil impurities on the surface of the titanium mesh can be effectively removed; at the same time, graphite is introduced as a surface agent, and after calcination under nitrogen protection, a uniform Ti@X conductive substrate is formed on the surface of the titanium mesh. The high conductivity of graphite can completely isolate the direct contact between the titanium mesh and the electrolyte, avoid the generation of new oxide film, and at the same time, build an efficient electron transport channel, effectively reduce the charge transfer impedance, and solve the core problem of the oxide film hindering electron transport; The method does not require complex structure design or expensive materials, and only through a simple process of cleaning, graphite surface modification and hydrothermal growth, the performance can be improved: the graphite surface agent is widely available and low in cost; the hydrothermal reaction conditions are mild, without high temperature and pressure or special equipment; and no polymer adhesive is used throughout, which not only reduces the material cost, but also avoids the insulation problem caused by the adhesive, and is suitable for commercial application process.

[0034] Example 2 A preparation method of an in-situ grown potassium ion battery positive electrode material based on a hydrothermal method, comprising the following steps: S1, 25ml of concentrated hydrochloric acid is added to 75ml of deionized water, stirred and mixed with a glass rod to obtain a cleaning solution; S2, cut 1*1cm titanium mesh into a beaker, sequentially ultrasonic cleaned with the cleaning solution, ethanol and deionized water, and then placed in a vacuum drying oven at 60°C for 8h; S3, the cleaned titanium mesh is immersed in the surface agent dispersion liquid, and the surface agent is adsorbed on the surface of the titanium mesh through the surface tension of the surface agent. The titanium mesh with adsorbed surface agent is transferred to a 60°C oven for 2h baking to remove adsorbed water; S4, the dried titanium mesh with adsorbed surface agent is further treated to obtain a Ti@X conductive substrate; S5, 0.158g of potassium permanganate is added to 60ml of deionized water, and stirred with a glass rod until the solute is completely dissolved. The solution is transferred to a 100ml constant volume bottle, and deionized water is added to 100ml to obtain a purple precursor solution; S6, 0.2ml of 1M H2SO4 is added to the 60ml precursor solution; S7, the mixed solution of S6 is placed in a 100ml polytetrafluoroethylene tank, and the Ti@X substrate is placed in the tank and transferred to a stainless steel autoclave for reaction at 200°C for 30min; S8, the reacted electrode is washed with deionized water and ethanol alternately for 3 times, and finally the electrode is vacuum dried at 60°C for 6 hours to obtain a binder-free Ti@X@MnO2 electrode; S9, the Ti@MnO2 electrode is prepared by replacing the Ti@X substrate in the above steps with a titanium mesh, and the rest of the conditions remain unchanged, and finally a Ti@MnO2 composite electrode is obtained; The potassium ion battery electrode prepared in Example 2 was used as a working electrode in a three-electrode system to complete electrochemical tests, the reference electrode was Ag / AgCl, a platinum black electrode was used as an auxiliary electrode, and 0.5M K2SO4 was used as an electrolyte. The cycle performance and rate performance are shown in the following table and FIG. 2. Figure 3 -Appendix Figure 4 .

[0035] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. A method for preparing a potassium-ion battery cathode material, characterized in that, Includes the following steps: S1. Take 25ml of concentrated hydrochloric acid and add it to 75ml of deionized water. Stir with a glass rod to mix and obtain a cleaning solution. S2. Place the cut 1×1cm titanium mesh into a beaker, and clean it with cleaning solution, ethanol and deionized water in sequence by ultrasonic cleaning. Then place it in a vacuum drying oven at 60℃ for 8 hours. S3. Immerse the cleaned titanium mesh in the surface agent dispersion. The surface agent is adsorbed onto the surface of the titanium mesh by the surface tension of the surface agent. Transfer the titanium mesh after adsorbing the surface agent to a 60℃ oven for 2 hours to bake and remove the adsorbed water. S4. Further process the dried titanium mesh with adsorbed surface agent to obtain Ti@X conductive substrate; S5. Take 0.158g of potassium permanganate and add it to 60ml of deionized water. Stir with a glass rod until the solute is completely dissolved. Transfer the solution to a 100ml volumetric flask and dilute to 100ml with deionized water to obtain a purple precursor solution. S6. Add 0.2 ml of 1 M H₂SO₄ to 60 ml of the precursor solution; S7. Place the mixed solution from step S6 into a 100ml polytetrafluoroethylene container, then place the Ti@X substrate into the container and transfer it to a stainless steel autoclave to react at 200℃ for 30min. S8. Rinse the reacted electrode three times alternately with deionized water and ethanol, and finally dry the electrode under vacuum at 60°C for 6 hours to obtain a binder-free Ti@X@MnO2 electrode. S9. Preparation of Ti@MnO2 electrode: In the above steps, the Ti@X substrate is replaced with a titanium mesh, and the other conditions remain unchanged, finally obtaining the Ti@MnO2 composite electrode.

2. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step 3, the surface agent is graphite, the amount of surface agent used is 100mg, and the amount of deionized water is 50ml.

3. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step 4, the further treatment is high-temperature calcination, with the calcination conditions being 350℃ for 2 hours and a heating rate of 2℃ / min.

4. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step 7, the Ti@X substrate is placed in the tank, and the placement method is vertical.

5. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S5, the potassium permanganate is of analytical grade (AR grade), and an electronic balance with an accuracy of 0.1 mg must be used during the weighing process to ensure that the weighing error is ≤ ±0.5 mg.

6. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S7, the polytetrafluoroethylene tank needs to be ultrasonically cleaned with concentrated nitric acid (65%) and deionized water for 15 minutes each before use, and then dried in an oven at 120°C for 2 hours to ensure that there is no organic residue or moisture on the surface of the tank.

7. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S8, the deionized water used in the rinsing process has a conductivity of ≤10μS / cm, the ethanol is anhydrous ethanol (purity ≥99.7%), and the electrode must be completely immersed and ultrasonically treated for 5 minutes each time it is rinsed.

8. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S9, the replacement operation must be carried out in a clean glove box (humidity ≤5%, oxygen content ≤1ppm), and the surface grease must be wiped off with acetone before the titanium mesh is replaced.

9. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S3, the preparation temperature of the surface agent dispersion is 25±2℃, and a magnetic stirrer is used to stir at a speed of 300r / min for 30min during dispersion to ensure that the graphite surface agent is uniformly dispersed in deionized water.

10. The method for preparing a potassium-ion battery cathode material according to claim 1, characterized in that, In step S4, the high-temperature calcination must be carried out in a nitrogen atmosphere (purity ≥99.99%). During the heating process, nitrogen is introduced at a flow rate of 50 mL / min. After the calcination is completed, the sample is cooled to room temperature in the furnace before being taken out.

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