Preparation method and application of mica modified graphite negative electrode material
By introducing mica powder into the graphite matrix to form an optimized SEI layer, the interfacial instability problem of graphite anode materials is solved, and the performance of potassium-ion batteries is improved, especially in terms of initial coulombic efficiency, rate performance and cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-05
- Publication Date
- 2026-03-31
AI Technical Summary
When graphite is used as a negative electrode material for potassium-ion batteries, it suffers from low initial coulombic efficiency, poor rate performance, and insufficient cycle stability. This is mainly due to the unstable formation of an undesirable solid electrolyte interphase (SEI) layer at the graphite/electrolyte interface, which leads to problems such as poor electronic insulation, increased interfacial impedance, and delayed potassium ion transport.
By introducing mica powder into a graphite matrix, its high dielectric properties and surface adsorption capacity are utilized to form a thin and dense SEI layer rich in inorganic components. This weakens the interfacial electric field, removes trace amounts of water and HF from the electrolyte, enhances the mechanical stability of the SEI, and optimizes interfacial kinetics.
It significantly improves the initial coulombic efficiency, rate performance, and cycle stability of potassium-ion batteries, enhances the adsorption and desorption capacity of potassium ions, and improves electrochemical performance.
Smart Images
Figure CN121769018A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to a method for preparing and applying a mica-modified graphite anode material. Background Technology
[0002] When graphite is used as an anode material in potassium-ion batteries, it faces challenges such as low initial coulombic efficiency (approximately 71%) and poor rate performance (e.g., at 500 mA g). -1 The capacity is only 100.1 mAh g. -1 Issues such as insufficient cycle stability (failure after 50 cycles) arise. These challenges mainly stem from the formation and dynamic evolution of an undesirable solid electrolyte interphase (SEI) layer at the graphite / electrolyte interface, specifically manifested as: 1) Formation and persistent instability of non-ideal SEI layer: Traditional KPF6-based electrolytes continuously decompose on the graphite surface, easily forming a thick, porous SEI layer rich in organic components. This SEI layer has poor electronic insulation, easily decomposes and consumes electrolyte and active potassium ions, resulting in low initial coulombic efficiency, continuously increasing interfacial impedance, and its fragility makes it unable to effectively protect the electrode.
[0003] 2) The SEI layer is susceptible to electrolyte corrosion and lacks sufficient mechanical strength: Trace amounts of water and HF in the electrolyte are the main causes of SEI chemical instability, which can accelerate the dissolution and destruction of the SEI. At the same time, the volume expansion and contraction of graphite during potassium ion insertion / extraction will subject the SEI layer to huge mechanical stress. If the SEI strength is insufficient, it is easy to crack and peel off, exposing the fresh electrode surface and further aggravating electrolyte decomposition.
[0004] 3) Delayed interfacial dynamics: The disordered and complex composition of traditional SEI layer structures hinders the rapid transport of potassium ions. In addition, the non-uniform electric field distribution at the graphite interface may also affect the desolvation and efficient intercalation of potassium ions, resulting in a sluggish overall charge transfer dynamics and affecting rate performance.
[0005] While current solutions include high-concentration electrolytes, artificial SEI layers, or complex carbon-based composite material modifications, these often suffer from drawbacks such as high cost, complex processes, poor compatibility, or difficulty in achieving multi-dimensional synergistic optimization. Therefore, there is an urgent need for a low-cost, simple, and efficient interface control technology to precisely guide the SEI formation process, achieve multi-dimensional synergistic stabilization, and comprehensively optimize interface dynamics. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a method for preparing mica-modified graphite anode materials with low process cost and simple operation.
[0007] Another technical problem to be solved by the present invention is to provide the application of the mica-modified graphite anode material.
[0008] To address the aforementioned problems, the present invention provides a method for preparing a mica-modified graphite anode material, characterized in that: the method involves mixing and dispersing mica powder, graphite material, conductive agent, and binder in an N-methylpyrrolidone (NMP) solvent at a mass ratio of 1:16:2:2 to obtain an anode slurry with a concentration of 262.5 g / L; the anode slurry is coated onto a current collector, and after drying and cutting, the mica-modified graphite anode material is obtained.
[0009] The mica powder is ground natural muscovite powder with a specification of 3000 mesh and an average particle size of 5~6μm.
[0010] The graphite material is at least one of natural graphite, artificial graphite, graphene, carbon nanotubes, or hard carbon.
[0011] The conductive agent is at least one of acetylene black, Ketjen black, and conductive carbon black; the binder is at least one of polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC).
[0012] The mixing method is at least one of mechanical stirring and ball milling, and the mixing time is 6 to 12 hours.
[0013] The drying conditions refer to drying at 80~120℃ for 10~24 hours using one of the following methods: vacuum drying, oven drying, or freeze drying.
[0014] A mica-modified graphite anode material prepared by the method described above.
[0015] The application of the mica-modified graphite anode material described above is characterized in that: the mica-modified graphite anode material is used in the preparation of potassium-ion or lithium-ion secondary batteries.
[0016] The potassium-ion secondary battery is prepared by the following method: Step S1: By mass, mix 6-8 parts of active PB, 2-3 parts of conductive agent and 1-2 parts of binder in N-methylpyrrolidone (NMP) and stir overnight to obtain a positive electrode slurry with a concentration of 200 g / L; coat the positive electrode slurry onto an aluminum foil current collector, and after drying and cutting, obtain the positive electrode sheet; Step S2: By mass, mix 7-8 parts of mica-modified graphite anode material, 1-2 parts of conductive agent and 1-2 parts of binder in N-methylpyrrolidone (NMP) and stir overnight to obtain an anode slurry with a concentration of 262.5 g / L; coat the anode slurry onto a copper foil current collector, and after drying and cutting, obtain the anode sheet; Step S3: Assemble and encapsulate the negative electrode, positive electrode, separator, and KPF6-based electrolyte to obtain a potassium-ion secondary battery.
[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention introduces mica into a graphite matrix, utilizing its high dielectric properties and surface adsorption capacity to achieve precise control of the graphite / electrolyte interface. Specifically, mica effectively weakens the interfacial electric field, guiding the formation of a thin, dense, inorganic-rich solid electrolyte interphase (SEI) layer, thereby reducing irreversible potassium ion depletion and improving the initial coulombic efficiency. Simultaneously, mica efficiently removes trace amounts of water and HF from the electrolyte, inhibiting the continuous decomposition of the SEI and electrode corrosion at the source, and enhancing the mechanical stability of the SEI to cope with graphite volume changes, thus significantly improving the material's adsorption and desorption capacity for potassium ions.
[0018] 2. This invention prepares electrodes by simply mixing mica powder with materials such as graphite in one step. The process is low-cost and easy to operate, avoiding multi-step chemical synthesis and complex coating processes, thereby optimizing the surface interface dynamics of carbon materials and making it easy to industrialize.
[0019] 3. Using the mica-modified graphite anode material prepared according to this invention as the anode material for potassium-ion secondary batteries can significantly improve a series of performance characteristics, including the initial coulombic efficiency, rate performance, cycle stability, and potassium-ion diffusion kinetics. Tests showed that the potassium-ion secondary battery prepared based on this composite material achieved good performance at 0.2 C (1 C = 279 mAh g⁻¹). -1 At the specified current density, the KPF6-based electrolyte exhibited a capacity of 270 mAh g⁻¹. -1 It has a high capacity, a stable capacity retention of 74% after 800 cycles, and also exhibits excellent rate performance. Attached Figure Description
[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0021] Figure 1 This is a schematic diagram illustrating the mechanism of action of the nano-graphite material provided in Comparative Example 1 of the present invention.
[0022] Figure 2 This is a schematic diagram illustrating the mechanism of action of the mica-modified graphite composite material provided in Embodiment 1 of the present invention.
[0023] Figure 3 The left image shows the Comsol simulation diagram of the electric field distribution of the nano-graphite material provided in Comparative Example 1 of this invention, and the right image shows a schematic diagram of the electric field action. Figure 4The left image shows the Comsol simulation diagram of the electric field distribution of the mica-modified graphite composite material provided in Embodiment 1 of the present invention, and the right image shows the electric field effect.
[0024] Figure 5 The images show the SEI characterization diagrams and interface and bulk dynamics analysis diagrams of the mica-modified graphite composite material ||K battery provided in Example 1 and the graphite ||K battery provided in Comparative Example 1. Specifically: (a) is a schematic diagram of the SEI insulation performance test of the batteries provided in Example 1 and Comparative Example 1 after 5 cycles; (b) is a data graph of the SEI insulation performance of the batteries provided in Example 1 and Comparative Example 1 after 5 cycles; (c) is a high-resolution transmission electron microscope image of the negative electrode obtained from the mica-modified graphite composite material and nano-graphite material after 5 cycles of the battery provided in Example 1; (d) shows the effect of mica decomposition on in-situ SEI formation during the cycling process of the batteries provided in Example 1 and Comparative Example 1; (e) shows the Si2p and Al content of the two graphite negative electrodes after 5 cycles of the batteries provided in Example 1 and Comparative Example 1. (f) The content of 2p, C1s, and O1s varies with sputtering depth; (g) High-resolution XPS spectra of Si2p, Al2p, C1s, and F1s of the two graphite anodes after 5 cycles of the batteries provided in Example 1 and Comparative Example 1; (g) 3D time-of-flight secondary ion mass spectrometry fragment reconstruction diagrams of the batteries provided in Example 1 and Comparative Example 1 after 5 cycles; (h) Comparison of activation energy of the anodes of the batteries provided in Example 1 and Comparative Example 1; (i) Impedance spectra of the battery provided in Example 1 at different voltages during cycling; (j) Distributed relaxation time data of the battery provided in Example 1 at different voltages during cycling.
[0025] Figure 6 The figures show the electrochemical performance of the half-cell systems provided in Example 1 and Comparative Example 1 of this invention. Specifically: (a) shows the cyclic voltammetry curves of the mica-modified graphite composite material and the nano-graphite material at a scan rate of 0.05 mV / s within a voltage range of 0–3 V; (b) shows the cyclic voltammetry curves of the mica-modified graphite composite material and the nano-graphite material at 0.2 C (1C = 279 mAh g⁻¹). -1 (c) is the charge-discharge curve of the first cycle at a certain rate; (d) is the rate performance of mica-modified graphite composite material and nano-graphite material in the current density range of 0.2 C to 2 C; (e) is the cycle stability of the half-cell system at a rate of 0.2 C; (f) is the cycle stability curve of the half-cell system at a rate of 0.4 C. Detailed Implementation
[0026] A method for preparing mica-modified graphite anode material is disclosed. The method involves mixing and dispersing mica powder, graphite material, conductive agent, and binder in a mass ratio of 1:16:2:2 (in g) in N-methylpyrrolidone (NMP) solvent. The mixing method is at least one of mechanical stirring and ball milling, and the mixing time is 6-12 hours to ensure uniform dispersion of the components. After mixing, a negative electrode slurry with a concentration of 262.5 g / L is obtained. The negative electrode slurry is coated onto a current collector and dried at 80-120℃ for 10-24 hours using one of vacuum drying, oven drying, or freeze drying, preferably oven drying. The material is then cut to obtain the mica-modified graphite anode material.
[0027] Among them, the mica powder is natural white mica powder that has been ground, with a specification of 3000 mesh and an average particle size of 5~6μm, in order to ensure uniform dispersion and interface control effect.
[0028] The graphite material is at least one of natural graphite, artificial graphite, graphene, carbon nanotubes or hard carbon, preferably natural graphite or artificial graphite.
[0029] The conductive agent is at least one of acetylene black, Ketjen black, and conductive carbon black; the binder is at least one of polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC).
[0030] The amount of mica modification used in this invention needs to be strictly controlled. If the amount added is too low, the interface regulation effect will not be obvious; if the amount added is too high, it may affect the conductivity and ion diffusion of the electrode, and increase the cost of the electrode.
[0031] An application of a mica-modified graphite anode material, which is used in the preparation of potassium-ion or lithium-ion secondary batteries.
[0032] Potassium-ion secondary batteries are prepared by the following method: Step S1: By mass, mix 6-8 parts of active PB, 2-3 parts of conductive agent and 1-2 parts of binder in N-methylpyrrolidone (NMP) and stir overnight to obtain a positive electrode slurry with a concentration of 200 g / L; coat the positive electrode slurry onto an aluminum foil current collector, and after drying and cutting, obtain the positive electrode sheet; Step S2: By mass, mix 7-8 parts of mica-modified graphite anode material, 1-2 parts of conductive agent and 1-2 parts of binder in N-methylpyrrolidone (NMP) and stir overnight to obtain an anode slurry with a concentration of 262.5 g / L; coat the anode slurry onto a copper foil current collector, and after drying and cutting, obtain the anode sheet; Step S3: Assemble and encapsulate the negative electrode, positive electrode, separator, and KPF6-based electrolyte to obtain a potassium-ion secondary battery.
[0033] Example 1 Preparation of mica-modified graphite anode materials: 10 g mica powder, 160 g graphite powder, 20 g conductive agent and 20 g binder were mixed and dispersed in 0.8 L NMP (AR, 99%, Aladdin) solution and stirred overnight with a magnetic stirrer for 12 hours to obtain the negative electrode slurry. The negative electrode slurry was uniformly coated on a copper foil current collector and then dried in an oven at 80℃ for 24 hours. It was then cut into circular negative electrode sheets with a diameter of 1.2 cm to obtain the mica-modified graphite negative electrode material.
[0034] A potassium metal || mica-modified graphite composite material is prepared by combining mica-modified graphite electrodes, potassium metal electrodes, glass fiber diaphragms, and 0.8 M KPF6 / EC:DEC electrolyte, and then encapsulated.
[0035] Comparative Example 1 Commercial nanographite materials were obtained using commercially pure graphite without any processing.
[0036] The corresponding potassium metal || commercial nano-graphite material was prepared using this nano-graphite material, and the preparation method was the same as in Example 1.
[0037] Electrochemical characterization was performed on batteries prepared using the composite material obtained in Example 1 and the nano-graphite material obtained in Comparative Example 1 as negative electrodes. The results are shown in [reference needed]. Figures 1-6 .
[0038] like Figure 1 As shown, from an electrochemical perspective, pure nano-graphite materials used as anodes typically exhibit the following characteristics: Graphite itself lacks control over the interfacial electric field and the chemical environment of the electrolyte. Under extremely strong electronic fields, the SEI layer formed on the graphite surface is usually thick, uneven, and rich in organic matter, resulting in poor mechanical stability and easy breakage and repair during cycling, consuming active cations. Trace amounts of water, HF, and other impurities in the electrolyte continuously corrode the graphite surface and SEI, leading to reduced coulombic efficiency and shorter cycle life. Simultaneously, the graphite surface has a high adsorption / desorption energy barrier for ions, resulting in poor interfacial charge transfer kinetics.
[0039] Electrodes were prepared by simply mixing mica powder with pristine nanographite sheets, such as... Figure 2As shown, mica, as a low-cost and readily available natural mineral, effectively weakens the original interfacial electric field by forming a reverse polarization electric field on the graphite surface through its unique high dielectric properties. This electric field modulation can guide the electrolyte to reduce and generate a thinner, denser, inorganic-rich, and mechanically stable SEI layer. On the other hand, mica has excellent adsorption properties, which can efficiently remove trace amounts of water and HF from the electrolyte, inhibiting the chemical decomposition of the SEI and electrode corrosion at the source, while generating excellent SEI components, greatly enhancing the chemical and mechanical stability of the SEI. This synergistic strategy of "physical field modulation and chemical environment management" can effectively regulate the electronic structure and interfacial dynamics of graphite: the thin, dense, and inorganic-rich SEI layer can effectively prevent direct contact between the internal active graphite and the electrolyte, inhibit the occurrence of side reactions, and reduce irreversible capacity loss. This inhibitory effect helps to improve the coulombic efficiency of the battery and improve the overall electrochemical performance. Furthermore, this SEI layer also helps to form a high potassium ion conductivity and strong electronic insulation SEI film.
[0040] To understand the mechanism by which mica regulates the graphite / electrolyte interface at the atomic / electronic level, Comsol simulations were used to plot the two-dimensional electric field distribution near the interface. In the nano-graphite system, the electric field lines are highly concentrated on the graphite surface, exhibiting extremely strong field strength, such as... Figure 3 As shown on the left. This causes potassium ions and anions to repel each other, leading the anions to move away from the interface, as... Figure 3 As shown on the right.
[0041] In contrast, in the mica-graphite composite system, mica acts as a buffer medium, dispersing and absorbing some of the electric field lines, making the local electric field acting on the electrolyte interface smoother and more uniform, such as... Figure 4 As shown on the left. This weakens the electric field that causes potassium ions and anions to repel each other, allowing anions to approach the interface and have a greater chance of participating in the formation of the SEI, such as... Figure 4 As shown on the right.
[0042] This weakened interfacial electric field has a crucial impact on the behavior of potassium ions. Figure 5 (ab) shows the schematic diagram and data graph of the SEI insulation performance generated after cycling of mica-modified graphite composite material and nano-graphite material. The results show that the SEI resistance of mica-modified graphite is as high as 103.4 MΩ, which is much higher than the 5.54 MΩ of the SEI formed by nano-graphite material, indicating that mica-modified graphite generates a strong electronically insulating SEI. Figure 5 (c) According to HRTEM studies, after 5 repeated charge-discharge cycles, a uniform interface layer with a thickness of ~10 nm was observed on mica-modified graphite. Figure 5(d) This intuitively demonstrates that mica-modified graphite can not only actively decompose and generate SEI in situ, but also remove trace amounts of water and HF generated by anion hydrolysis. In contrast, the SEI generated by ordinary nano-graphite electrodes will be destroyed by HF, causing continuous electrolyte decomposition. Characterizing the interface of the graphite anode is crucial for elucidating the relationship between graphite and potassium storage performance. For example... Figure 5 As shown in (e), the mica-modified graphite composite material exhibited a weaker C signal and higher Al and Si content with increasing etching depth, indicating that the mica-modified graphite composite material forms an SEI rich in inorganic components. This is attributed to the mica regulation on the graphite surface, which prevents the electrolyte from contacting the graphite and effectively inhibits electrolyte decomposition. To further analyze the differences in chemical composition and atomic bonding characteristics between the two negative electrodes, XPS fine spectroscopy was performed, and the results are shown below. Figure 5 As shown in (f), the Si 2p and Al 2p spectra indicate that mica participated in the SEI formation. Figure 5 As shown in (g), the TOF-SIMS images reveal the same results as XPS, indicating that the presence of these components in the SEI of the mica-modified graphite composite synergistically enhances the rapid migration of K at the interface, improves interfacial stability, and avoids continuous electrolyte decomposition and side reactions. These results strongly suggest that the microstructure modulation of graphite by the mica modification layer can produce a high-potassium-ion-conductive SEI film, thereby contributing to the rapid reaction kinetics of potassium ions. The activation energy during the interfacial desolvation / migration reaction was calculated according to the classical Arrhenius law, such as... Figure 5 As shown in (h). Mica-modified graphite composites via SEI K + The diffusion activation energy is 47.59 kJ·mol⁻¹. -1 It is far lower than the 55.32 kJ / mol of original graphite. -1 The result is consistent with Figure 5 The DRT results in (ij) are in excellent agreement, indicating the ability of the mica-modified graphite electrode system to rapidly transfer charge, which is also the reason for its excellent rate and cycle performance.
[0043] Figure 6 The cyclic voltammetry (CV) curves in (a) show that no obvious redox peaks were observed in mica itself during potassium storage, confirming that it does not provide additional capacity but rather acts as an interface modifier. The corresponding initial charge-discharge curves are shown below. Figure 6 As shown in (b), this conclusion is further verified. Thanks to the optimized interface described above, the mica-modified graphite anode exhibits excellent rate performance ( Figure 6 c). Its reversible capacity at all current densities is significantly higher than that of pure graphite anodes, demonstrating rapid potassium storage kinetics. Most importantly, when the current density reverts from high rate to 50 mA g... -1Upon completion, the capacity was fully recovered, highlighting the robustness of the electrode structure. This significant performance advantage confirms that the mica-induced inorganic SEI effectively promotes charge transfer and ensures Kc... + Highly efficient migration. Excellent rate performance ultimately translates into long-term cycling stability. Figure 6 d). At a rate of 0.2C, the mica-modified graphite anode maintained 74% of its capacity after 800 cycles, demonstrating excellent cycle life. In stark contrast, the pure graphite anode experienced a rapid capacity decay and failure after only 200 cycles. At a rate of 0.4C, the mica-modified graphite anode could cycle stably for 160 cycles, while the nano-graphite anode rapidly decayed in capacity until failure. Figure 6 e). This result strongly demonstrates that mica, by constructing a stable interfacial phase, significantly inhibits the failure of active materials and the continuous decomposition of electrolytes during cycling, thereby achieving a substantial performance improvement.
[0044] In summary, this invention modulates the interfacial dynamics of the graphite anode through a mica modification layer. Mica successfully improves potassium ion transport efficiency, reduces initial capacity loss, and enhances stability. With the optimized structure, the mica-modified graphite composite exhibits a higher affinity for potassium ions, thereby improving rate performance. Furthermore, mica inhibits solvent decomposition, promotes the formation of a thin and uniform solid electrolyte interphase (SEI) film, and lowers the potassium ion migration barrier. Thanks to these significant advantages, the mica-modified graphite composite anode exhibits excellent cycling stability (74% capacity retention after 800 cycles) and high rate performance (173 mAh g⁻¹ at 2C) in conventional electrolytes. -1 ).
[0045] Example 2: A corresponding PB||mica-modified graphite composite full cell was prepared using the mica-modified graphite anode material obtained in Example 1. The process is as follows: Step S1: Mix 7g of active PB, 2g of conductive carbon black and 1g of PVDF binder in 40mL of NMP (AR, 99%, Aladdin) solution and stir overnight to obtain the positive electrode slurry; coat the positive electrode slurry onto an aluminum foil current collector, and then dry it at 80℃ for 24 hours, and cut it into circular PB positive electrodes with a diameter of 1.2 cm; Step S2: Mix 8g of mica-modified graphite anode material, 1g of conductive carbon black and 1g of PVDF binder in 30mL of NMP (AR, 99%, Aladdin) solution and stir overnight to obtain anode slurry; coat the anode slurry onto copper foil current collector, then dry at 80℃ for 24 hours, and cut into circular mica-modified graphite anode sheets with a diameter of 1.2 cm; Step S3: Combine the mica-modified graphite negative electrode, PB positive electrode, glass fiber separator, and 0.8 M KPF6 / EC:DEC electrolyte to form PB||mica-modified graphite composite material, and encapsulate it to obtain the final product.
Claims
1. A method for preparing a mica-modified graphite anode material, characterized in that: The method is that mica powder, graphite material, conductive agent and binder are mixed and dispersed in N-methyl pyrrolidone solvent according to a mass ratio of 1:16:2:2, so that a negative electrode slurry with a concentration of 262.5 g / L is obtained; the negative electrode slurry is coated on a current collector, and after drying and cutting, a mica modified graphite negative electrode material is obtained.
2. The method for preparing mica modified graphite negative material according to claim 1, characterized in that: The mica powder is a ground natural white mica powder with a specification of 3000 meshes and an average particle size of 5-6 μm.
3. The method for preparing mica modified graphite negative material according to claim 1, characterized in that: The graphite material is at least one of natural graphite, artificial graphite, graphene, carbon nanotube or hard carbon.
4. The method for preparing mica modified graphite negative material according to claim 1, characterized in that: The conductive agent is at least one of acetylene black, ketjen black and conductive carbon black; and the binder is at least one of polyvinylidene fluoride and sodium carboxymethyl cellulose.
5. The method for preparing mica modified graphite negative material according to claim 1, characterized in that: The mixing mode is at least one of mechanical stirring and ball milling, and the mixing time is 6-12 hours.
6. The method for preparing mica modified graphite negative material according to claim 1, characterized in that: The drying condition is that one of vacuum drying, oven drying or freeze drying is adopted at 80-120 ℃ for 10-24 hours.
7. A mica modified graphite negative electrode material prepared by the method of any one of claims 1-7.
8. The use of a mica-modified graphite negative electrode material according to claim 7, characterized in that: The mica modified graphite negative electrode material is used in the preparation of a potassium ion or lithium ion secondary battery.
9. The use of a mica-modified graphite negative electrode material according to claim 8, characterized in that: The potassium ion secondary battery is prepared by the following method: Step S1, 6-8 parts of active PB, 2-3 parts of conductive agent and 1-2 parts of binder are mixed and stirred in N-methyl pyrrolidone overnight according to mass fraction, so that a positive electrode slurry with a concentration of 200 g / L is obtained; the positive electrode slurry is coated on an aluminum foil current collector, and after drying and cutting, a positive electrode sheet is obtained; Step S2, 7-8 parts of mica modified graphite negative electrode material, 1-2 parts of conductive agent and 1-2 parts of binder are mixed and stirred in N-methyl pyrrolidone overnight according to mass fraction, so that a negative electrode slurry with a concentration of 262.5 g / L is obtained; the negative electrode slurry is coated on a copper foil current collector, and after drying and cutting, a negative electrode sheet is obtained; Step S3, the negative electrode sheet, the positive electrode sheet, the separator and the KPF6-based electrolyte are assembled and packaged, so that a potassium ion secondary battery is obtained.