A Phytochemical-Ti3C2MXene Composite Material and Its Preparation Method

Abstract

This invention relates to the field of battery electrode materials technology, and provides a phytic acid-Ti3C2MXene composite material and its preparation method. The preparation method includes: placing Ti3C2MXene, phytic acid, and a solubilizer in a solvent and stirring until a mixed solution is obtained; freezing with liquid nitrogen to obtain a solid product; freeze-drying the solid product under vacuum to obtain an aerogel; heat-treating the aerogel under an inert atmosphere and then cooling it to room temperature to obtain the phytic acid-Ti3C2MXene composite material. In the phytic acid-Ti3C2MXene composite material prepared by this method, phytic acid coats the outer surface of Ti3C2MXene and intercalates between the layers of Ti3C2MXene, effectively suppressing Ti3C2MXene stacking and volume expansion.

Description

Technical Field

[0001] This invention belongs to the field of battery electrode material technology, and more specifically, relates to a method for preparing an phytic acid-Ti3C2MXene composite material and its application. Background Technology

[0002] Lithium-ion batteries have been widely used in portable digital products, electric vehicles, and energy storage due to their advantages such as high open-circuit voltage, long cycle life, high energy density, and no memory effect. However, the low natural reserves and high price of lithium limit the further development of lithium-ion batteries in electric vehicles and large-scale energy storage. Potassium, abundant in nature and inexpensive, has become an ideal alternative to lithium. To meet the sustainable demand for high-energy-density potassium-ion batteries, improving the specific capacity and cycle stability of potassium-ion battery anode materials has become an important research direction for potassium-ion batteries.

[0003] MXene materials, possessing metallic conductivity and complex surface chemistry, are promising emerging materials in the field of energy storage. Ti3C2 MXene, in particular, offers numerous advantages for potassium-ion battery anode materials. It can be exfoliated from top to bottom into a two-dimensional layered structure with good conductivity and a high specific surface area. Furthermore, Ti3C2 MXene exhibits both high conductivity and a high specific surface area. Additionally, its performance can be further enhanced through doping and surface modification. However, Ti3C2 MXene has a small interlayer spacing, and during charge-discharge cycling, it is prone to volume expansion and layered stacking, which is detrimental to potassium ion insertion / extraction. Therefore, the aim is to develop a Ti3C2 MXene anode material for potassium-ion batteries with further improved electrochemical performance. Summary of the Invention

[0004] To address the aforementioned deficiencies in the prior art, the present invention aims to provide a method for preparing a phytic acid-Ti3C2MXene composite material. The phytic acid-Ti3C2MXene composite material prepared by this method exhibits high specific capacity, rate performance, and cycle stability as an electrode material for potassium-ion batteries.

[0005] Another object of the present invention is to provide a phytic acid-Ti3C2 MXene composite material.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0008] S1. Place Ti3C2 Mxene, phytic acid and a co-solvent in a solvent and stir until homogeneous to obtain a mixed solution;

[0009] S2. Freeze the mixed solution obtained in step S1 with liquid nitrogen to obtain a solid product;

[0010] S3. The solid product obtained in step S2 is freeze-dried under vacuum to obtain an aerogel;

[0011] S4. The aerogel obtained in step S3 is heat-treated under an inert atmosphere and then cooled to room temperature to obtain phytic acid-Ti3C2MXene composite material;

[0012] In step S1, the mass ratio of Ti3C2 Mxene to phytic acid is 1:1.5 to 5.

[0013] This invention first involves mixing Ti3C2 MXene, phytic acid, and a co-solvent. Part of the phytic acid etches the Ti3C2 MXene material, increasing its specific surface area and facilitating full contact between the electrode and the electrolyte, exposing more active sites and thus improving the electrode material's specific capacity. The other part of the phytic acid fully penetrates the interlayer space of the Ti3C2 MXene material, increasing its interlayer spacing and preventing interlayer stacking after repeated potassium ion insertion and extraction. This optimizes the potassium ion diffusion channels, improves the lithium ion diffusion rate, and effectively enhances the material's rate performance.

[0014] Subsequently, the material was rapidly frozen with liquid nitrogen to obtain a fluffy aerogel, which can increase the porosity between material layers and facilitate the diffusion rate of potassium ions. In addition, the use of liquid nitrogen freezing can maximize the preservation of the layered structure of Ti3C2 Mxene and the structure of phytic acid adhering to the surface of Ti3C2 Mxene. Then, the material was freeze-dried, which can remove moisture from the material while ensuring that the material structure remains unchanged, thus keeping the interlayer spacing unchanged. Sintering then promotes the full composite of the material, which is conducive to the bonding and tight adhesion of phytic acid and Ti3C2 MXene material to the surface of Ti3C2 MXene material, resulting in a phytic acid-Ti3C2 Mxene composite material (P@TC).

[0015] Phytic acid, rich in hydroxyl groups, effectively enhances the hydrogen bonding interaction between P and Ti3C2 Mxene layers, ensuring their efficient combination. Phytic acid has a structure of six phosphate groups symmetrically linked to a cyclohexanehexaol ring. Each phosphate group can dissociate and provide two protons. Phytic acid exhibits a spatially stable conformation with one phosphate group at the axial carbon 2 position and five phosphate groups at the equatorial position. This structure readily interacts with positively charged metal ions. Therefore, the phytic acid-Ti3C2 Mxene composite material prepared in this invention provides more opportunities for potassium ion intercalation, significantly improving the capacity of potassium-ion batteries when applied as a negative electrode.

[0016] Furthermore, in step S1, the mass ratio of Ti3C2 Mxene to phytic acid is 1:1.5 to 2.5.

[0017] Furthermore, the heat treatment in step S4 involves heating from the ambient temperature to 500-600°C at a heating rate of 1-10°C / min and then holding at that temperature.

[0018] Calcination within this temperature range is conducive to the formation of disordered carbon structures. The increase in disordered carbon structures gives the prepared phytic acid-Ti3C2 Mxene composite material more active sites and provides more defects, which is conducive to the insertion and extraction of potassium ions, thereby improving the rate performance of the electrode material.

[0019] Furthermore, the heat treatment holding time in step S4 is 1 to 3 hours.

[0020] Furthermore, the inert atmosphere in step S4 is nitrogen and / or argon, preferably argon.

[0021] Further, the co-solvent in step S1 is one or more of polyethylene glycol, N,N-dimethylformamide, and dimethyl sulfoxide. Preferably, the co-solvent is polyethylene glycol, wherein the molecular weight of the polyethylene glycol is 400. The addition of the co-solvent facilitates the entry of phytic acid molecules into the interlayer of the Ti3C2 MXene material.

[0022] Furthermore, in step S1, the mass ratio of the co-solvent to phytic acid is 1:60 to 200.

[0023] Furthermore, the solvent in step S1 is deionized water and / or N-methylpyrrolidone.

[0024] Furthermore, the stirring time in step S1 is 1 to 3 hours.

[0025] Furthermore, the temperature of liquid nitrogen freezing in step S2 is -160 to -200°C.

[0026] Furthermore, the liquid nitrogen freezing time in step S2 is 5 to 20 minutes.

[0027] Furthermore, the freeze-drying time in step S3 is 48–96 hours.

[0028] Furthermore, the freeze-drying in step S3 is carried out in a freeze dryer.

[0029] Furthermore, the present invention also provides an electrode comprising the phytic acid-Ti3C2MXene composite material prepared by the above preparation method.

[0030] Furthermore, the phytic acid-Ti3C2 MXene composite material accounts for 65-75% of the weight percentage in the electrode.

[0031] Furthermore, the present invention also provides a method for preparing an electrode: the phytic acid-Ti3C2Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF, and N-methylpyrrolidone is added and stirred to form a uniform slurry which is coated on copper foil and then vacuum dried to obtain an electrode sheet.

[0032] Furthermore, the present invention also provides a potassium-ion battery comprising the electrode prepared as described above.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the phytic acid-Ti3C2Mxene composite material prepared in this invention, phytic acid coats the outer surface of Ti3C2Mxene and intercalates between the Ti3C2Mxene layers. The synergistic effect of these two components allows the prepared phytic acid-Ti3C2Mxene composite material to maintain its layered structure while increasing the interlayer spacing, thus broadening the diffusion and charge transport pathways of potassium ions and effectively suppressing Ti3C2Mxene stacking and volume expansion. This significantly improves the material's rate performance and cycle stability. Furthermore, because phytic acid readily interacts with positively charged metal ions, it provides more active sites for potassium ion intercalation, further enhancing the material's capacity. Attached Figure Description

[0035] Figure 1 The image shows the XRD pattern of the phytic acid-Ti3C2 Mxene composite material obtained in Example 1 of this invention.

[0036] Figure 2 a and Figure 2 b corresponds to the SEM images of Ti3C2Mxene material and the phytic acid-Ti3C2Mxene composite material of Example 1 of this invention, respectively.

[0037] Figure 3 a and Figure 3 b are TEM images of Ti3C2Mxene material and phytic acid-Ti3C2Mxene composite material of Example 1 of this invention, respectively.

[0038] Figure 4 Button batteries made from the phytic acid-Ti3C2 MXene composite material of Example 1 and the Ti3C2 MXene material used in Comparative Example 1, at 100 mAg -1 Charging and discharging cycle performance at current density.

[0039] Figure 5 A button cell made from the phytic acid-Ti3C2 Mxene composite material of Example 1 of this invention was tested at 1000 mAg. -1 Charging and discharging cycle performance at current density.

[0040] Figure 6 The phytic acid-Ti3C2 MXene composite material of Example 1 and the Ti3C2 MXene material used in Comparative Example 1 were used to fabricate button cells with an energy density of 100–1000 mAg. -1 Charging / discharging rate performance at current density. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in this embodiment are conventional reagents, methods and equipment in this technical field.

[0042] The Ti3C2 Mxene material described in this invention was purchased from Suzhou Beike Nanotechnology Co., Ltd., CAS No.: 12363-89-2.

[0043] Example 1

[0044] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0045] S1. Weigh 0.2g Ti3C2 Mxene, 0.3g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0046] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0047] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 96 hours to obtain a fluffy aerogel.

[0048] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 500°C at a heating rate of 5°C / min under an inert atmosphere and held for 3 hours. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0049] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0050] Example 2

[0051] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0052] S1. Weigh 0.2g Ti3C2 Mxene, 0.5g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0053] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0054] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 96 hours to obtain a fluffy aerogel.

[0055] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 500°C at a heating rate of 5°C / min under an inert atmosphere and held for 3 hours. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0056] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0057] Example 3

[0058] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0059] S1. Weigh 0.2g Ti3C2 Mxene, 0.3g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0060] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0061] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 72 hours to obtain a fluffy aerogel.

[0062] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 600°C at a heating rate of 1°C / min under an inert atmosphere and held for 2 hours. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0063] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.5:1.25:1.25, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0064] Example 4

[0065] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0066] S1. Weigh 0.2g Ti3C2 Mxene, 0.3g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0067] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0068] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 72 hours to obtain a fluffy aerogel.

[0069] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 500°C at a heating rate of 10°C / min under an inert atmosphere and held for 2 hours. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0070] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 6.5:1.75:1.75, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0071] Example 5

[0072] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0073] S1. Weigh 0.2g Ti3C2 Mxene, 0.3g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0074] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0075] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 96 hours to obtain a fluffy aerogel.

[0076] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 550°C at a heating rate of 5°C / min under an inert atmosphere and held for 1.2 h. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0077] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0078] Example 6

[0079] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0080] S1. Weigh 0.2g Ti3C2 Mxene, 1.0g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0081] S2. Freeze the mixed solution obtained in step S1 at -200°C using liquid nitrogen for 10 min to obtain a solid product;

[0082] S3. The solid product obtained by freezing with liquid nitrogen in step S2 was freeze-dried under vacuum for 96 hours to obtain a fluffy aerogel.

[0083] S4. The aerogel obtained in step S3 is ground and heated from 25°C to 550°C at a heating rate of 5°C / min under an inert atmosphere and held for 1.2 h. It is then naturally cooled to room temperature to obtain the target product, phytic acid-Ti3C2 MXene composite material.

[0084] This embodiment also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material (P@TC) obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto a copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0085] Comparative Example 1

[0086] This comparative example also provides a method for preparing the negative electrode sheet: Ti3C2 Mxene, acetylene black, and binder PVDF are mixed in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto copper foil and dried in a vacuum drying oven for 12 hours to obtain the negative electrode sheet.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that the amount of phytic acid in step S1 is 0.15g.

[0089] Comparative Example 3

[0090] A method for preparing a phytic acid-Ti3C2 MXene composite material includes the following steps:

[0091] S1. Weigh 0.2g Ti3C2 Mxene, 0.3g phytic acid and 0.005g polyethylene glycol (400) and place them in pure water and stir for 2 hours;

[0092] S2. Place the mixed solution obtained in step S1 in a vacuum drying oven and dry it at 120°C for 48 hours to obtain a black solid.

[0093] S3. The solid obtained in step S3 is ground and heated from 25°C to 500°C at a heating rate of 5°C / min under an inert atmosphere and held for 3 hours. It is then naturally cooled to room temperature to obtain phytic acid-Ti3C2 MXene composite material.

[0094] This comparative example also provides a method for preparing the electrode sheet: the phytic acid-Ti3C2 Mxene composite material obtained above is mixed with acetylene black and binder PVDF in a mass ratio of 7.0:1.5:1.5, and N-methylpyrrolidone is added and stirred to form a uniform slurry. This slurry is then coated onto copper foil and dried in a vacuum drying oven for 12 hours to obtain the electrode sheet.

[0095] Performance testing

[0096] The phytic acid-Ti3C2 MXene composite material and Ti3C2 Mxene material prepared in this invention were analyzed by XRD, SEM, and TEM. The results are as follows: Figure 1-3As shown.

[0097] Battery assembly: The battery was assembled in an argon-filled glove box, using the negative electrode obtained in the examples and comparative examples as the working electrode, a potassium metal sheet as the counter electrode, glass fiber as the separator, and KPF6 as the electrolyte to form a coin cell for electrochemical performance testing.

[0098] Charge / discharge test: The charging / discharging voltage range of the button cell battery is 0.1–3V, and the discharge rate is 100–1000 mAg within this voltage range. -1 The current density was used for charge-discharge cycle testing, and the test results are shown in Table 1 and 2. Figures 4-6 As shown.

[0099] Figure 1 The XRD patterns of Example 1 and Comparative Example 1 show that the diffraction peaks of the phytic acid-Ti3C2MXene composite material and the Ti3C2MXene material are basically consistent, indicating that phytic acid does not change the phase structure of the layered Ti3C2MXene material. At the same time, a large peak appears at around 27°, indicating that the uncrystallized components in the material have increased, representing the presence of more disordered structures, such as disordered carbon.

[0100] Figure 2 a and Figure 2 b are SEM images of Ti3C2Mxene material and phytic acid-Ti3C2Mxene composite material of Example 1 of the present invention, respectively. By comparison, it can be found that the phytic acid-Ti3C2Mxene composite material prepared by the present invention is still a layered structure, and phytic acid forms an obvious coating layer on the surface of Ti3C2Mxene. This makes it possible to improve the structural stability of phytic acid-Ti3C2Mxene composite material and suppress the volume expansion of Ti3C2Mxene when the composite material of the present invention is used as a negative electrode material for potassium-ion batteries, thereby effectively improving the cycle performance of potassium-ion batteries.

[0101] Figure 3 a and Figure 3 b are TEM images of Ti3C2Mxene material and phytic acid-Ti3C2Mxene composite material of Example 1 of the present invention, respectively. By comparison, it can be found that the interlayer spacing of phytic acid-Ti3C2Mxene composite material prepared in the present invention is increased compared with Ti3C2Mxene.

[0102] Figure 4 Button batteries made from the phytic acid-Ti3C2MXene composite material of Example 1 and the Ti3C2MXene material of Comparative Example 1 were tested at 100 / Ag. -1 Charge-discharge cycle performance at current density. (From...) Figure 4It can be seen that the initial discharge specific capacity of the phytic acid-Ti3C2 Mxene composite material prepared in Example 1 is 742.2 / Ahg. -1 After 100 cycles, the specific capacity was 185.5 / Ahg. -1 The initial discharge specific capacity of Ti3C2 MXene material is 248.3 Ahg. -1 After 100 cycles, the specific capacity is only 90 / Ahg. -1 The results above show that using phytic acid composite Ti3C2 MXene can effectively improve the reversible capacity and cycle stability of the material.

[0103] Figure 5 The phytic acid-Ti3C2 Mxene composite material used in Example 1 of this invention was used to fabricate a button cell at 1000 / Ag. -1 Charge-discharge cycle performance at current density. (From...) Figure 5 It can be seen that the phytic acid-Ti3C2 Mxene composite material prepared in Example 1 has an initial discharge specific capacity of 543.1 / Agh. -1 After 500 cycles, the specific capacity remained at 128.8 / Ahg. -1 This demonstrates that the phytic acid-Ti3C2 Mxene composite material prepared by this invention still exhibits good long-term cycling stability and structural stability under high-power charge-discharge conditions.

[0104] Figure 5 Button batteries made from the phytic acid-Ti3C2MXene composite material of Example 1 and the Ti3C2MXene material of Comparative Example 1 have an efficiency of 100-1000 Ag. -1 Charge-discharge rate performance at current density. (From...) Figure 5 It can be seen that the phytic acid-Ti3C2 Mxene composite material prepared in Example 1 exhibits good performance at 100, 200, 300, 500, and 1000 g / Ag. -1 The reversible capacities obtained at the given current densities were 144.8, 92.3, 57.4, 52.3, and 43.3 / Ahg. -1 However, the capacities of Ti3C2 MXene materials at the same rate current density are 50.0, 45.0, 38.0, 30.0, and 22.0 / Ahg. -1 The results above show that the phytic acid-Ti3C2Mxene composite material prepared in this invention can effectively improve the specific capacity and rate performance of the material under high current density.

[0105] The electrode sheets obtained in the embodiments and comparative examples of the present invention were used to fabricate a button cell at a current density of 100 / Ahg. -1 Under the conditions, charge-discharge cycle tests were conducted, and the results are shown in Table 1.

[0106] Table 1

[0107]

[0108]

[0109] As shown in Table 1, the phytic acid-Ti3C2 Mxene composite material prepared in this invention achieves an initial discharge specific capacity of 717.2 / Ahg. -1 The discharge specific capacity can reach 125.3 Ahg after 500 cycles. -1 The initial coulombic efficiency (initial charge specific capacity / initial discharge specific capacity) reached over 57.8%. As can be seen from Example 1 and Comparative Example 1, the phytic acid-Ti3C2 Mxene composite material prepared in this invention exhibits significantly improved cycle stability and specific capacity compared to Ti3C2 Mxene material. Example 1 and Comparative Example 2 show that the phytic acid content can affect the material's capacity and cycle stability. Insufficient phytic acid content makes it difficult for a coating layer to form on the Ti3C2 Mxene surface, leading to volume expansion during charge-discharge cycles and reducing the number of active sites, thereby decreasing the material's cycle stability and capacity. Example 1 and Comparative Example 3 demonstrate that the rapid freezing with liquid nitrogen in this invention effectively maintains the structural integrity of the phytic acid intercalation in the Ti3C2 Mxene material, preventing structural collapse and improving the material's capacity and cycle stability.

[0110] The above embodiments are preferred experimental methods of the present invention, but the implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a phytic acid-Ti3C2 MXene composite material, characterized in that, Includes the following steps: S1. Ti3C2 Mxene, phytic acid, and a co-solvent are placed in a solvent and stirred until homogeneous to obtain a mixed solution; the co-solvent in step S1 is one or more of polyethylene glycol, N,N-dimethylformamide, and dimethyl sulfoxide. S2. Freeze the mixed solution obtained in step S1 with liquid nitrogen to obtain a solid product; the liquid nitrogen freezing time is 5 to 20 minutes. S3. The solid product obtained in step S2 is freeze-dried under vacuum to obtain an aerogel; S4. The aerogel obtained in step S3 is heat-treated under an inert atmosphere and then cooled to obtain phytic acid-Ti3C2 MXene composite material; the heat treatment in step S4 is to heat from the ambient temperature to 500-600℃ at a heating rate of 1~10℃ / min and then hold at that temperature. In step S1, the mass ratio of Ti3C2 Mxene to phytic acid is 1:1.5~5.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of Ti3C2 Mxene to phytic acid is 1:1.5~2.

5.

3. The preparation method according to claim 1, characterized in that, The heat preservation time is 1 to 3 hours.

4. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the co-solvent to phytic acid is 1:60~200.

5. A phytic acid-Ti3C2 MXene composite material prepared according to any one of claims 1 to 4.

6. An electrode, characterized in that, The electrode comprises the phytic acid-Ti3C2 MXene composite material as described in claim 5.

7. The electrode according to claim 6, characterized in that, The phytic acid-Ti3C2 MXene composite material accounts for 65-75% of the weight of the electrode.

8. A potassium-ion battery, characterized in that, The potassium-ion battery comprises the electrode as described in claim 6 or 7.

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