A type of N,P modified Ti3C2T x Preparation methods and applications of electrode materials

Abstract

A type of N,P modified Ti3C2T x The preparation method and application of electrode materials relate to the field of lithium-ion battery anode materials. The preparation steps are as follows: 1) Prepare Ti3C2T x The material was uniformly dispersed in deionized water, and then ultrasonically purified to obtain a homogeneous Ti3C2T. x 1) Dispersion; 2) Add N and P compound solution to the dispersion and stir to mix; 3) Pour the mixture obtained in 2) into the liner of a polytetrafluoroethylene reactor and carry out a solvothermal reaction. After cooling, wash the obtained sample with deionized water by centrifugation and vacuum drying to obtain N,P@Ti3C2T x Materials. This method uses one of urea phosphate, aminotrimethylene phosphonic acid, or N-bis(phosphohydroxymethyl)glycine as the N and P source, and employs a solvothermal method in Ti3C2T x The construction of N and P functional groups on the material surface effectively modulates the surface charge distribution, accelerates carrier transport and diffusion at the material interface, stabilizes the material structure, improves lithium-ion diffusion performance, and promotes the development of Ti3C2T. x Application of materials in lithium-ion battery anodes.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery anode materials, specifically relating to a method for rapidly hydrothermally modifying Ti3C2T using N and P compounds. x Methods for functional groups on material surfaces and their application in lithium-ion batteries. Background Technology

[0002] Rechargeable lithium-ion batteries (LIBs) offer advantages such as high energy density and long cycle life, making them the most promising electrochemical energy storage devices after traditional lead-acid, nickel-iron, and nickel-metal hydride batteries. They have broad application prospects in rail transportation, electric vehicles, mobile phones, and aerospace. Electrode materials are a key factor determining the overall performance of the battery, significantly influencing electrochemical potential and reaction kinetics. Improving the specific capacity of the negative electrode material is crucial for enhancing the energy density and power density of lithium-ion batteries.

[0003] MXene is a novel two-dimensional layered material with the general formula M. n+1 X n T x (n=1~4), where M represents a transition metal (Sc, Ti, Zr, Hf, V, Nb, Cr, Mo, etc.), X is carbon or nitrogen, and T is... x The presence of terminal groups (-O, -F, -Cl, -OH, etc.) and the conductive metal carbide core layer endow MXene materials with excellent electronic conductivity. Furthermore, the surface of MXene can be modified with functional groups; phosphorus and sulfur-containing functional groups created through surface functionalization provide abundant active sites for lithium-ion storage, thus improving the material's specific capacity. Simultaneously, the large specific surface area and nanolayer structure of MXene facilitate interlayer diffusion of ions, enhancing the material's rate performance and volumetric specific capacity. However, MXene materials resemble two-dimensional graphene structures. Interlayer van der Waals forces and hydrogen bonds cause material re-stacking during long-term cycling, hindering the diffusion and migration of lithium ions between material layers. Additionally, the complex surface end-group structures can react with the electrolyte, leading to irreversible electrolyte consumption and decomposition, passivating the material's surface structure, hindering carrier adsorption and diffusion, and severely deteriorating the material's high-rate electrochemical performance. Summary of the Invention

[0004] This invention aims to improve Ti3C2T x The electrochemical stability and rate performance of the material are improved by proposing the use of the thermal decomposition of N and P organic compounds in Ti3C2T. xA method for N and P co-doping the surface of materials involves the interaction of chemical bonds such as PO and NH bonds in P2O7 and NH2 functional groups generated after the pyrolysis of N and P compounds with Ti-O, Ti-OH, and Ti-F bonds in the bulk material, resulting in N-P co-doping in Ti3C2T. x Ti-P, Ti-OP, and Ti-N bonds are formed on the material surface to achieve Ti3C2T x Surface functional group modification optimizes the surface charge distribution and improves the electrochemical performance of materials. This invention introduces various N and P functional groups during synthesis to regulate the electron cloud structure of the material surface, effectively realizing the synthesis of Ti3C2T. x High-rate, long-life lithium storage applications of materials.

[0005] This invention is achieved through the following technical solution:

[0006] A type of N,P modified Ti3C2T x The method for preparing electrode materials is characterized by comprising the following steps:

[0007] (1) Prepare Ti3C2T x The material was uniformly dispersed in deionized water and ultrasonically purified to obtain a homogeneous Ti3C2T. x Dispersion;

[0008] (2) Dissolve a certain mass of N and P compounds in deionized water and obtain a homogeneous N and P compound solution by magnetic stirring;

[0009] (3) Slowly add the corresponding volume of N and P compound solution to the dispersion, and mix the N and P compound solution and the dispersion thoroughly and evenly under magnetic stirring.

[0010] (4) The uniform dispersion obtained in step (3) is poured into the liner of a polytetrafluoroethylene reactor and reacted with solvent thermally at a certain temperature for a certain time. Then, the product is washed by centrifugation with deionized water and further dried under vacuum to obtain the target product N,P@Ti3C2T x Material.

[0011] Furthermore, in step (1), the volume of deionized water is 120 mL, and the dispersed Ti3C2T x The material weighs 30mg.

[0012] Furthermore, in step (2), the volume of deionized water is 120 mL, and the dissolved N and P compounds are the same as those dispersed in step (1) as Ti3C2T. x The material mass ratios are 5:1, 10:1, and 15:1.

[0013] Furthermore, in step (3), the volume of the corresponding solution added is 120 ml, and the N and P compound solutions are one of urea phosphate solution, aminotrimethylene phosphonic acid solution, and N-bis(phosphohydroxymethyl)glycine solution.

[0014] Furthermore, in step (4), the solvothermal reaction temperature is 100–140 °C, the solvothermal reaction time is 4–8 h, the vacuum drying temperature is 80 °C, and the vacuum drying time is 12 h.

[0015] N,P modified Ti3C2T prepared according to the method described above x The electrode material is used in the negative electrode of lithium-ion batteries, characterized by the use of a solvothermal method in Ti3C2T. x The construction of N and P functional groups on the material surface effectively modulates the surface charge distribution, accelerates carrier transport and diffusion at the material interface, stabilizes the material structure, and improves the lithium-ion diffusion performance. Lithium-ion batteries assembled using this material significantly improve the initial discharge specific capacity and charge specific capacity, thus advancing the development of Ti3C2T. x Application of materials in lithium-ion battery anodes.

[0016] The mechanism of this invention is as follows:

[0017] The urea phosphate (chemical formula CO(NH2)2·H3PO4) and aminotrimethylenephosphonic acid (chemical formula C3H) used in this invention 12 NO9P3), N-bis(phosphohydroxymethyl)glycine (chemical formula C4H) 11 In a solvothermal reaction, the N and P compounds begin to decompose when the system temperature reaches above 120°C. The reaction is more rapid when the temperature reaches above 160°C. During the reaction, the N and P compound molecules decompose to produce substances containing P2O7, NH2, etc. The PO and NH bonds in the decomposition products will react with Ti3C2T. x The C-Ti-O or C-Ti-OH bonds in the outer Ti atomic layer of the material react to form chemical bonds such as Ti-OP, Ti-P, Ti-N, and P=O. These Ti-OP, Ti-P, and Ti-N bonds facilitate surface charge transfer, increase interlayer spacing, and improve the electrochemical kinetics of the material, thereby achieving Ti3C2T. x High power density applications of materials.

[0018] The innovation of this invention lies in:

[0019] The urea phosphate, aminotrimethylene phosphonic acid, and N-bis(phosphonohydroxymethyl)glycine used in this invention are commonly used phosphate fertilizers and industrial additives. These three substances serve as nitrogen and phosphorus sources, and are used in Ti3C2T... xIntroducing -N and -P end groups into the material surface can form Ti-OP, Ti-P, and Ti-N chemical bonds, which can expand the interlayer spacing, improve the electronic structure of the material surface, provide more lithium-ion adsorption sites, and increase the lithium storage capacity of the material. At the same time, the introduction of N and P functional groups can also provide support for the material during cycling, effectively improving the problem of re-stacking in long-term cycling, so that the modified material has excellent rate performance and cycling stability.

[0020] The method of this invention uses one of urea phosphate, aminotrimethylene phosphonic acid, and N-bis(phosphohydroxymethyl)glycine as the N and P source, and employs a solvothermal method in Ti3C2T x The construction of N and P functional groups on the material surface effectively modulates the surface charge distribution, accelerates carrier transport and diffusion at the material interface, stabilizes the material structure, and improves the lithium-ion diffusion performance. Lithium-ion batteries assembled using this material significantly improve the initial discharge specific capacity and charge specific capacity, thus advancing the development of Ti3C2T. x Application of materials in lithium-ion battery anodes. Attached Figure Description

[0021] Figure 1 These are the X-ray diffraction (XRD) patterns of the materials prepared in Example 2 and the comparative example.

[0022] Figure 2 Initial Ti3C2T prepared in a comparative manner x Scanning electron microscope (SEM) image of the material.

[0023] Figure 3 It is the N,P-Ti3C2T prepared in Example 2 x Scanning electron microscope (SEM) image of the material.

[0024] Figure 4 (a) is the N,P-Ti3C2T prepared in Example 2. x The energy dispersive spectroscopy (EDS) spectrum of phosphorus in the material. Figure 4 (b) is the N,P-Ti3C2T prepared in Example 2. x Nitrogen energy dispersive spectroscopy (EDS) of the material.

[0025] Figure 5 These are the first charge-discharge performance curves of the materials prepared in Examples 1, 2, 3 and Comparative Example 11.

[0026] Figure 6 The graphs show the low current density cycling performance of the half-cell materials prepared in Example 2 and the comparative example.

[0027] Figure 7 The graphs show the high current density cycling performance of the half-cells of the materials prepared in Example 2 and the comparative example.

[0028] Figure 8 The graphs show the half-cell rate performance of the materials prepared in Example 2 and the comparative example.

[0029] Figure 9 The graphs show the half-cell rate performance of the materials prepared in Example 9 and the comparative example.

[0030] Figure 10 The graph shows the rate performance of the half-cells of the materials prepared in Example 10 and the comparative example. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] Example 1: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0033] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0034] (2) Disperse 1.5g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0035] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0036] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 120°C for 6 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0037] Example 2: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0038] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0039] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0040] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0041] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 120°C for 6 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0042] Example 3: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0043] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0044] (2) Disperse 4.5g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0045] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0046] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 120°C for 6 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0047] Example 4: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0048] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0049] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0050] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0051] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 100°C for 6 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0052] Example 5: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0053] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0054] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0055] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0056] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 140°C for 6 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0057] Example 6: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0058] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0059] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0060] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0061] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 160°C for 6 hours. The hydrothermal product was washed with deionized water by vacuum filtration and dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0062] Example 7: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0063] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0064] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0065] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0066] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal environment at 120°C for 4 hours. The hydrothermal product was washed with deionized water and then vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0067] Example 8: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0068] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0069] (2) Disperse 3g of urea phosphate evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain a urea phosphate solution;

[0070] (3) Slowly add the urea phosphate solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0071] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 160°C for 8 hours. The hydrothermal product was washed with deionized water by vacuum filtration and dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0072] Example 9: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0073] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0074] (2) Disperse 3g of aminotrimethylenephosphonic acid evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain an aminotrimethylenephosphonic acid solution;

[0075] (3) Slowly add the aminotrimethylenephosphonic acid solution prepared in (2) to the Ti3C2T solution prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0076] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 120°C for 8 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0077] Example 10: A method for preparing an N, P modified Ti3C2Tx electrode material, comprising the following steps:

[0078] (1) 0.3g of prepared Ti3C2T x The material was uniformly dispersed in 120 mL of deionized water and sonicated for 30 min to obtain homogeneous Ti3C2T. x Dispersion;

[0079] (2) Disperse 3g of N-bis(phosphohydroxymethyl)glycine evenly in 120mL of deionized water and stir with a magnetic stirrer for 30min to obtain an N-bis(phosphohydroxymethyl)glycine solution;

[0080] (3) Slowly add the N-bis(phosphohydroxymethyl)glycine solution prepared in (2) to the Ti3C2T prepared in (1). x In the dispersion, the solution and dispersion were then thoroughly mixed using a magnetic stirrer;

[0081] (4) The dispersion obtained in step (3) was uniformly transferred into the liners of four polytetrafluoroethylene reactors. The reactors were then placed in a hydrothermal reaction at 120°C for 8 hours. The hydrothermal product was washed with deionized water and vacuum dried at 80°C for 12 hours to obtain the target product N,P@Ti3C2T. x Material.

[0082] Comparative Example: A Ti3C2T x The method for preparing the material includes the following steps:

[0083] (1) 2 g of Ti3AlC2 precursor was slowly added to 32 mL of 40% hydrofluoric acid and stirred at room temperature for 48 h.

[0084] (2) After the reaction is complete, the mixture is washed by centrifugation with deionized water, first at 10000 r / min. –1 Centrifuge at 3500 rpm for 5 min to remove reacting acids and products, then centrifuge at 3500 rpm for 5 min. –1 Centrifuge at a speed of 5 min for 5 min, and repeat several times until the pH of the supernatant is 6;

[0085] (3) The precipitate was washed by vacuum filtration with deionized water and dried under vacuum at 80 °C for 12 h to finally obtain Ti3C2T x Material.

[0086] Test example:

[0087] Half-cell assembly: The N,P@Ti3C2T cells prepared in Examples 1, 2, and 3 were used... x Materials and Comparative Examples of Ti3C2T x The materials were mixed with Super P and PVDF in a mass ratio of 80:10:10 and coated, and then punched to obtain electrode sheets with a diameter of 12 mm. Using lithium metal as the negative electrode and LIB-111 high-voltage resistant electrolyte from Suzhou Duoduo Chemical Technology Co., Ltd. as the electrolyte, half-cells were assembled in an argon atmosphere glove box.

[0088] Charge-discharge testing: The charge-discharge voltage range of the coin cell half-cell is 3.0–0.01 V. Before the cycle test, three activation tests were performed at a current density of 15 mA / g, followed by charge-discharge cycle tests at current densities of 150 mA / g and 750 mA / g within the same voltage range. All electrochemical performance tests were conducted at 30 °C.

[0089] Figure 1 These are the XRD patterns of Example 2 and the comparative example. By comparison, it can be found that P-modified Ti3C2T x The sample still possesses good Ti3C2T properties x The sample exhibits a layered structure, with the (002) crystal plane diffraction peak corresponding to the layered structure along the c-axis. The modified sample shows a leftward shift in the (002) peak position, indicating an increase in the interlayer spacing. This promotes interlayer diffusion of lithium-ion materials and is beneficial for improving the electrochemical performance of the modified sample.

[0090] contrast Figure 2 , 3 The SEM images shown correspond to the comparative example and Example 2, revealing that the P-modified material still exhibits an accordion-like layered structure under the scanning electron microscope. Figure 3 );at the same time Figure 4 EDS testing of nitrogen and phosphorus elements in Example 2 showed that nitrogen and phosphorus elements were uniformly distributed in N,P-Ti3C2Tx, indicating that nitrogen and phosphorus elements were successfully incorporated into the material.

[0091] Figure 5 The figures show the first charge-discharge curves of the assembled half-cells in Examples 1, 2, 3, and the comparative example. It can be seen that the first charge-discharge specific capacity of the materials in Examples 2 and 3 is significantly improved. Specifically, the first discharge specific capacity of Example 2 is 799.8 mAh / g and the charging specific capacity is 342.1 mAh / g, while the first discharge specific capacity of Example 3 is 788.8 mAh / g and the charging specific capacity is 309.2 mAh / g. In contrast, the first discharge specific capacity of the comparative example is 459.6 mAh / g and the charging specific capacity is only 251.1 mAh / g.

[0092] Figure 6 The graph shows the cycling performance of the half-cells assembled in Example 2 and the comparative example after 300 cycles at a current density of 150 mA / g. After 300 cycles, the capacity of Example 2 is 193.1 mAh / g, with a capacity retention of 97.0%, while the capacity of the comparative example is only 117.3 mAh / g, with a capacity retention of 94.7%. Figure 7The graph shows the cycling performance of the half-cells assembled in Example 2 and the comparative example after 500 cycles at a current density of 750 mA / g. After 500 cycles, the capacity of Example 2 is 151.9 mAh / g, with a capacity retention of 97.7%, while the capacity of the comparative example is only 78.7 mAh / g, with a capacity retention of only 87.0%. Figure 8 The graph shows the rate performance of the half-cells assembled in Example 2 and the comparative example. Example 2 has a charge specific capacity of 160.9 mAh / g at a current density of 3000 mA / g, while the comparative example only shows a charge specific capacity of 54.8 mAh / g.

[0093] Figure 9 The graph shows the rate performance of the half-cells assembled in Example 9 and the comparative example. Example 9 exhibits a charge specific capacity of 235.3 mAh / g at a current density of 30 mA / g, which is significantly higher than the 194.4 mAh / g of the comparative example. Example 2 has a charge specific capacity of 126.9 mAh / g at a current density of 3000 mA / g, while the comparative example only exhibits a charge specific capacity of 54.8 mAh / g. Figure 10 The graph shows the rate performance of the half-cell assembled in Example 10 and the comparative example. Example 10 exhibits a charge specific capacity of 246.6 mAh / g at a current density of 30 mA / g, which is significantly higher than the 194.4 mAh / g of the comparative example.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An N,P modified Ti3C2T x The method for preparing electrode materials is characterized by, Includes the following steps: (1) Prepare Ti3C2T x The material was uniformly dispersed in deionized water and ultrasonically purified to obtain a homogeneous Ti3C2T. x Dispersion; (2) Dissolve a certain mass of N and P compounds in deionized water and obtain a homogeneous N and P compound solution by magnetic stirring; (3) Slowly add the corresponding volume of N and P compound solution to the dispersion, and mix the N and P compound solution and the dispersion thoroughly and evenly under magnetic stirring. The volume of the corresponding solution added is 120 ml, and the N and P compound solutions are one of the following: urea phosphate solution, aminotrimethylene phosphonic acid solution, and N,N-bis(phosphohydroxymethyl)glycine solution; (4) The uniformly dispersed liquid obtained in step (3) is poured into the liner of a polytetrafluoroethylene reactor and subjected to a solvothermal reaction at a certain temperature for a certain time. The solvothermal reaction temperature is 100-140 °C and the solvothermal reaction time is 4-8 h. The product is then washed by centrifugation with deionized water and further dried under vacuum to obtain the target product N,P@Ti3C2T x The material is vacuum dried at a temperature of 80 °C for 12 h.

2. The N, P modified Ti3C2T according to claim 1 x The method for preparing electrode materials is characterized by, In step (1), the volume of deionized water is 120 mL, and the dispersed Ti3C2T x The material weighs 30mg.

3. The N, P modified Ti3C2T according to claim 1 x The method for preparing electrode materials is characterized by, In step (2), the volume of deionized water is 120 mL, and the dissolved N and P compounds are the same as the Ti3C2T dispersed in step (1). x The material mass ratios are 5:1, 10:1, and 15:

1.

4. The N,P modified Ti3C2T prepared by the method according to claim 1 x Electrode materials are used in the negative electrode of lithium-ion batteries.

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