A method for encapsulation modification to improve the specific capacity of multi-layer Ti3C2T x ​

Abstract

The present invention discloses a coating modification method for improving the specific capacity of multi-layer Ti3C2T x , belonging to the field of electrochemistry technology. The method comprises the following steps: preparing multi-layer Ti3C2T x by using HF solution and Ti3AlC2 as raw materials; dissolving 1,1-dicarboxyferrocene and cobalt source in an organic solvent, fully mixing, and then adding the multi-layer Ti3C2T x , heating and stirring, centrifuging, precipitating, and vacuum drying to obtain the coated and modified Ti3C2T x (Ti3C2T x -b). The specific capacity of MXene can be effectively improved by using the method of the present invention.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology, and particularly relates to a method for improving the specific capacity of multi-layer Ti3C2T x by encapsulation modification. Background Art

[0002] As a new type of two-dimensional material, MXene has shown extraordinary potential in the field of energy storage due to its excellent ionic conductivity and fast ion diffusion rate. So far, more than 40 kinds of MXene have been developed. However, the problem of its low specific capacity limits its development in the field of energy storage, especially for multi-layer Ti3C2T x For example, its specific capacity is only 50-70 mAh / g, and even for single-layer Ti3C2T x , its specific capacity is only about 100 mAh / g.

[0003] To improve this problem, the most mainstream methods currently include surface modification, construction of heterojunctions, and layer expansion. Among them, surface modification optimizes the activity of surface functional groups of Ti3C2T x by chemical substitution or atomic doping, so that its specific capacity is increased to a certain extent. However, although this method can increase the specific capacity, the improvement amplitude is limited and it is difficult to meet the requirements of high energy density energy storage devices; the construction of heterojunctions utilizes the negative charge characteristics of Ti3C2T x to introduce positively charged metal ions or their oxides on the material surface through electrostatic adsorption or chemical bonding, and then carry out subsequent treatment to form a series of heterojunction materials based on Ti3C2T x . However, the construction of heterojunctions usually requires precise control of the material synthesis conditions and subsequent treatment parameters, the process is complex and difficult to mass-produce, and the construction of heterojunctions requires the tight combination of Ti3C2T x with other materials (such as metals or oxides), but the interfacial compatibility between different materials may be poor, resulting in an increase in contact resistance or insufficient interfacial stability; layer expansion is to graft organic long carbon chain functional groups at the end groups of Ti3C2T x , so that its layer spacing increases. Along with the introduction of new active sites, the specific capacity of Ti3C2T x will also be increased to a certain extent. However, it is difficult to precisely control in actual operation, which will lead to uneven layer spacing, and the structural stability of Ti3C2T x after layer expansion will be affected. Especially in the electrolyte environment or during long-term charge and discharge processes, it will cause the collapse of the interlayer structure or the shedding of functional groups. Summary of the Invention

[0004] In view of the above technical problems, the present invention proposes a method for improving the specific capacity of multi-layer Ti3C2T xMethod for modifying the specific capacity by encapsulation.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the objects of the present invention is to provide a method for modifying the specific capacity of multi-layer Ti3C2T x by encapsulation, comprising the following steps:

[0007] Prepare multi-layer Ti3C2T from HF solution and Ti3AlC2 as raw materials x ;

[0008] Dissolve 1,1-dicarboxyferrocene and cobalt source in an organic solvent, mix well, and then add the multi-layer Ti3C2T x , heat and stir, centrifuge, precipitate, and vacuum dry to obtain the modified multi-layer Ti3C2T after encapsulation modification x (denoted as: modified multi-layer Ti3C2T x -b).

[0009] The present invention first modifies Ti3AlC2 to obtain multi-layer Ti3C2T x , then preliminarily modifies ferrocene with cobalt element, and then utilizes the negative charge effect of the terminal functional groups of multi-layer Ti3C2T x to adsorb the modified ferrocene on its surface, so as to achieve the encapsulation effect. The rich functional groups of ferrocene provide a large number of active sites for the insertion and extraction of lithium ions, thus solving the problem of low specific capacity of the material. The introduction of Co element can replace the irreversible reaction of iron to a certain extent, thereby improving the cycle stability of the material. In addition, since the surface of Ti3C2T x is encapsulated by ferrocene, the stacking problem of the material itself during the cycle is inhibited, and the cycle stability of the material is further improved.

[0010] Further, the specific steps of the preparation method of the multi-layer Ti3C2T x are as follows: at 25-35 °C, add Ti3AlC2 to the HF solution and stir for 5-7 h, centrifuge and dry the obtained mixed solution to obtain multi-layer Ti3C2T x .

[0011] Furthermore, the dosage ratio of Ti3AlC2 to HF solution is 1 g∶20 mL; and / or

[0012] the process of adding Ti3AlC2 to the HF solution is completed within 3-5 min; and / or

[0013] the centrifugation conditions are: centrifuge at 5000 rpm for 5 min; and / or

[0014] The drying conditions are as follows: vacuum drying at 60 - 80°C for 6 - 12 h.

[0015] Further, the dosage ratio of 1,1 - dicarboxyl ferrocene, cobalt source, organic solvent and multi - layer Ti3C2T x is 0.33 g∶0.33 g∶50 mL∶0.2 g.

[0016] Furthermore, the cobalt source is selected from one of Co(NO3)2·6H2O, CoCl2 and CoSO4; and / or

[0017] the organic solvent is N,N - dimethylformamide.

[0018] Further, the conditions for heating and stirring are as follows: reacting at 120°C for 12 h; and / or, the conditions for centrifugation are as follows: centrifuging at 5000 rpm for 5 min; and / or, the drying conditions are as follows: drying at 60°C for 12 h.

[0019] The second object of the present invention is to provide a modified multi - layer Ti3C2T x -b obtained by the above - mentioned method.

[0020] The third object of the present invention is to provide an application of the modified multi - layer Ti3C2T x in battery preparation.

[0021] The fourth object of the present invention is to provide a battery electrode using the modified multi - layer Ti3C2T x .

[0022] The fifth object of the present invention is to provide a lithium - ion battery including the battery electrode.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] The specific capacity of the multi - layer Ti3C2T x prepared by the method of the present invention is increased from about 100 mAh / g to about 400 mAh / g; the alternating current impedance test shows that the modified Ti3C2T x -b shows a smaller diffusion impedance in the high - frequency region and a faster ion diffusion rate in the low - frequency region; after cycling 1000 times at a current density of 1 A / g, the Ti3C2T x -b still maintains a reversible specific capacity of 314.78 mAh / g; the modified Ti3C2T x -b can maintain a stable discharge specific capacity at different current densities. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 1 Scanning electron microscopy image of the multilayer Ti3C2T prepared in Example 1 x ;

[0027] Figure 2 SEM images of the modified multilayer Ti3C2T prepared in Example 1 x -b and the incompletely encapsulated and modified Ti3C2T prepared in Comparative Example 1 x -b; a is the incompletely encapsulated and modified Ti3C2T x -b after 3 h of reaction, b is the incompletely encapsulated and modified Ti3C2T x -b after 6 h of reaction, c is the SEM image of the modified multilayer Ti3C2T x -b, and d is the enlarged view of c;

[0028] Figure 3 XPS full spectrum of the modified multilayer Ti3C2T prepared in Example 1 x -b;

[0029] Figure 4 Charge-discharge cycling curves of the multilayer Ti3C2T x and the modified multilayer Ti3C2T x -b at 0.5 A / g;

[0030] Figure 5 Long-term cycling performance test of the modified multilayer Ti3C2T x -b in Example 1 and the modified single-layer Ti3C2T x -b in Comparative Example 2 at 0.1 A / g;

[0031] Figure 6 Rate performance test of the modified multilayer Ti3C2T x -b in Example 1;

[0032] Figure 7 AC impedance spectra of the Ti3C2T x before and after modification in Example 1;

[0033] Figure 8 SEM image of the modified single-layer Ti3C2T x -b in Comparative Example 2;

[0034] Figure 9 Charge-discharge cycling curves of Example 1 and Comparative Example 3 at a current density of 0.1 A / g. Detailed Embodiments

[0035] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as a limitation on the present invention, but rather as a more detailed description of certain aspects, features, and implementation manners of the present invention.

[0036] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0038] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0039] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0040] An embodiment of the present invention provides a method for wrapping and modifying to improve the specific capacity of multi-layer Ti3C2T x The method includes the following steps:

[0041] 1) Preparation of multi-layer Ti3C2T x Using HF solution (9M, AR) and Ti3AlC2 (400 mesh, AR) as raw materials to prepare multi-layer Ti3C2T x ;

[0042] 2) Dissolve 1,1-dicarboxyferrocene (AR) and a cobalt source in an organic solvent, mix well and then ultrasonicate for 1 h so that the cobalt element in the solution can fully react with ferrocene, and then add the multi-layer Ti3C2T x, heat and stir, centrifuge, precipitate, and vacuum dry to obtain the modified Ti3C2T x -b.

[0043] In some embodiments of the present invention, the preparation method of the multi-layer Ti3C2T x is as follows: at 25 - 35 °C, slowly add Ti3AlC2 to the HF solution and stir for 5 - 7 h. Put the obtained mixed solution into a centrifuge for centrifugation. After pouring out the supernatant, add deionized water to the precipitate and repeat centrifugation until the pH of the poured out supernatant is ≥ 6. Stop centrifugation, take down the precipitate for drying to obtain the multi-layer Ti3C2T x .

[0044] In some embodiments of the present invention, the dosage ratio of Ti3AlC2 to the HF solution is 1 g∶20 mL; the process of adding Ti3AlC2 to the HF solution is completed within 3 - 5 min; the conditions for centrifugation are: centrifuge at 5000 rpm for 5 min;

[0045] The conditions for drying are: vacuum dry at 80 °C for 6 h, or vacuum dry at 60 °C for 12 h.

[0046] In some embodiments of the present invention, the dosage ratio of 1,1-dicarboxyferrocene, cobalt source, organic solvent, and multi-layer Ti3C2T x is 0.33 g∶0.33 g∶50 mL∶0.2 g.

[0047] In some alternative embodiments, the cobalt source is one of Co(NO3)2·6H2O(AR), CoCl2(AR), and CoSO4(AR).

[0048] In some alternative embodiments, the organic solvent is N,N-dimethylformamide(AR).

[0049] In some alternative embodiments, the conditions for heating and stirring are: react at 120 °C for 12 h.

[0050] In some alternative embodiments, the conditions for centrifugation are: centrifuge at 5000 rpm for 5 min.

[0051] In some alternative embodiments, the conditions for drying are: vacuum dry at 60 °C for 12 h.

[0052] The embodiments of the present invention also provide a modified Ti3C2T x -b obtained by the above method. After modification, the multi-layer Ti3C2T xThe specific capacity is increased from about 100 mAh / g originally to about 400 mAh / g; the alternating current impedance test shows that the modified Ti3C2T x -b exhibits smaller diffusion impedance in the high-frequency region and faster ion diffusion rate in the low-frequency region; after cycling 1000 times at a current density of 1 A / g, the modified Ti3C2T x -b still maintains a reversible specific capacity of 314.78 mAh / g; the modified Ti3C2T x -b can maintain a stable discharge specific capacity at different current densities.

[0053] The embodiment of the present invention also provides an application of the modified multi-layer Ti3C2T x -b in battery preparation.

[0054] The embodiment of the present invention also provides a battery electrode, the raw materials of which include the modified multi-layer Ti3C2T x -b.

[0055] The embodiment of the present invention also provides a lithium-ion battery, including the battery electrode.

[0056] In the present invention, "room temperature" refers to 25 - 35 °C unless otherwise specified.

[0057] All raw materials used in the present invention are obtained by purchasing on the market.

[0058] The technical solution of the present invention will be further described below through examples.

[0059] Example 1

[0060] A method for encapsulating and modifying to improve the specific capacity of multi-layer Ti3C2T x includes the following steps:

[0061] 1) At 25 - 35 °C, slowly add 1 g of Ti3AlC2 to 20 mL of HF solution (concentration 40 wt%) (this step is completed within 4 min), stir for 6 h, put the obtained mixed solution into a centrifuge and centrifuge at 5000 rmp for 5 min. After pouring out the supernatant, add deionized water to the precipitate, repeat centrifugation until the pH of the poured out supernatant ≥ 6, then stop centrifugation, take down the precipitate and dry it at 80 °C for 6 h to obtain multi-layer Ti3C2T x ;

[0062] 2) Dissolve 0.33 g of 1,1-dicarboxyferrocene and 0.33 g of Co(NO3)2·6H2O in 50 mL of N,N-dimethylformamide (DMF), fully mix and then ultrasonicate for 1 h to enable the cobalt element in the solution to fully react with ferrocene, and then add 0.2 g of the multi-layer Ti3C2T prepared in step 1) x, stir at 120 °C for 12 h. After the reaction, place the solution in a centrifuge and centrifuge at 5000 rmp for 5 min. Take out the precipitate and dry it at 60 °C for 12 h to obtain the modified Ti3C2T x , namely the modified multi-layer Ti3C2T x -b.

[0063] Comparative Example 1

[0064] Prepare incompletely coated Ti3C2T x , and the method includes the following steps:

[0065] 1) At 25 - 35 °C, slowly add 1 g of Ti3AlC2 to 20 mL of HF solution (concentration 40 wt%) (this step is completed within 4 min), stir for 6 h, place the obtained mixed solution in a centrifuge and centrifuge at 5000 rmp for 5 min. After pouring out the supernatant, add deionized water to the precipitate and repeat centrifugation until the pH of the poured out supernatant ≥ 6, then stop centrifugation. Take down the precipitate and dry it at 80 °C for 6 h to obtain multi-layer Ti3C2T x ;

[0066] 2) Dissolve 0.33 g of 1,1-dicarboxyferrocene and 0.33 g of Co(NO3)2·6H2O in 50 mL of N,N-dimethylformamide (DMF), mix well and ultrasonic for 1 h to enable the cobalt element in the solution to fully react with ferrocene, then add 0.2 g of the multi-layer Ti3C2T prepared in step 1 x , stir at 120 °C for 3 h and 6 h respectively. After the reaction, place the solution in a centrifuge and centrifuge at 5000 rmp for 5 min. Take out the precipitate and dry it at 60 °C for 12 h to obtain incompletely coated Ti3C2T x , namely incompletely coated Ti3C2T x -b.

[0067] Comparative Example 2

[0068] 1) At 35 °C, add 3.2 g of LiF to 40 mL of HCl solution (concentration 9 M), stir for 10 min to fully dissolve it, then slowly add 2 g of Ti3AlC2 (this step is completed within 5 - 10 min), and stir at a constant temperature of 400 rmp for 24 h for etching; after the etching is completed, centrifuge the obtained mixture at 5000 rmp for 1 min, pour out the supernatant and add deionized water to repeat the above steps until the supernatant is black (at this time, the supernatant has an obvious Tyndall effect); then shake the solution well and place it in an ultrasonic cleaner for ice-water ultrasonic for 1 h. After the ultrasonic is over, centrifuge at 3500 rmp for 15 min again. After centrifugation is completed, freeze-dry the obtained black supernatant to obtain single-layer Ti3C2Tx ;

[0069] 2) Dissolve 0.33 g of 1,1 - dicarboxyferrocene and 0.33 g of Co(NO3)2·6H2O in 50 mL of N,N - dimethylformamide (DMF). After thorough mixing, sonicate for 1 h to enable the cobalt element in the solution to fully react with ferrocene. Then add 0.2 g of monolayer Ti3C2T x , stir at 120 °C for 12 h. After the reaction, place the solution in a centrifuge and centrifuge at 5000 rmp for 5 min. Take out the precipitate and dry it in vacuo at 60 °C for 12 h to obtain the modified monolayer Ti3C2T x , that is, modified monolayer Ti3C2T x - b.

[0070] Comparative Example 3

[0071] Same as Example 1, except that N,N - dimethylformamide was replaced with an equal volume of dimethylacetamide (DMAC).

[0072] Figure 1 The SEM image of the multi - layer Ti3C2T x prepared in Example 1. It can be seen from Figure 1 that the prepared multi - layer Ti3C2T x exhibits an accordion - like multi - layer structure under the scanning electron microscope.

[0073] Figure 2 The SEM images of the modified multi - layer Ti3C2T x - b prepared in Example 1 and the incompletely wrapped and modified Ti3C2T x - b prepared in Comparative Example 1. It can be seen from a in Figure 2 that when the reaction time is 3 h, partial coating layers begin to appear on the surface of Ti3C2T x - b. It can be seen from b in Figure 2 that when the reaction time is 6 h, the Ti3C2T x - b on both sides is wrapped by ferrocene, and an obvious layered structure is presented in the middle, but it is not completely wrapped. It can be seen from c and the enlarged view d in Figure 2 that when the reaction time is 12 h, the multi - layer Ti3C2T x has been completely wrapped, and the layered structure belonging to the multi - layer Ti3C2T x can be seen in the gaps of the modified multi - layer Ti3C2T x - b.

[0074] Figure 3 The full XPS spectrum of the modified multi - layer Ti3C2T x - b prepared in Example 1. It can be seen fromFigure 3 It can be seen that the wrapped material contains the characteristic element (Ti) of Ti3C2T x , as well as the characteristic elements (Fe, Co, and N) of the wrapping material. In addition, a large amount of C and O were also found in the full spectrum. Among them, C is mainly provided by the carbon skeleton in ferrocene and Ti3C2T x , while the O element is provided by the end groups of Ti3C2T x .

[0075] Application Example 1

[0076] The raw materials in Example 1 and Comparative Examples 1-3, as well as the prepared products, were used as active materials for battery assembly. The assembly method of the button battery is as follows:

[0077] 1) Preparation of the electrode sheet: 0.08 g of active material, 0.01 g of carbon black (acetylene black), and 0.01 g of polyvinylidene fluoride (PVDF) were mixed evenly and ground. After grinding, N-methylpyrrolidone (NMP) was slowly added dropwise, and after stirring into a paste, it was evenly coated on a copper foil (the size of the copper foil was 14 mm × 14 mm, the coating thickness was 100 µm, ensuring that the loading amount of each copper foil was between 2 - 2.5 mg, and the mass of the active substance was between 1.6 - 2 mg). After the copper foil was vacuum dried at 80 °C for 6 h, it was cut into a circular positive electrode sheet with a size of 14 × 14 mm using a cutter to obtain an electrode sheet with active components;

[0078] 2) Battery assembly: The electrode sheet with active substances prepared in step 1) was placed into a CR2025 battery case, then a PP separator (18 × 18 mm) was placed, 30 µL of a lithium secondary battery electrolyte (LB - 002) was slowly added dropwise to completely soak the electrode sheet, and then a lithium sheet (14 × 14 mm), nickel foam (14 × 14 mm), and a CR2025 battery case cover were placed in sequence. Then, it was pressed with a tablet press at a pressure of 50 Mpa for 5 s to obtain a button battery.

[0079] Figure 4 For the charge-discharge cycle curves of multilayer Ti3C2T x and modified multilayer Ti3C2T x -b at 0.5 A / g. It can be seen from the figure that the specific capacity of multilayer Ti3C2T x has been maintained below 100 mAh / g during 500 cycles, while the specific capacity of modified multilayer Ti3C2T x -b has increased to about 400 mAh / g. Before wrapping, the charge-discharge efficiency of multilayer Ti3C2T x in the first few cycles was much higher than 100%, indicating that at this time, multilayer Ti3C2T xDuring the charge and discharge process, there is irreversible intercalation / deintercalation of lithium ions. However, the material after coating modification maintains a 100% charge-discharge efficiency throughout the entire cycle, indicating that the material after coating modification has good cycling performance.

[0080] Figure 5 For the long cycling performance test of the modified multi-layer Ti3C2T x -b in Example 1 and the modified single-layer Ti3C2T x -b in Comparative Example 2 at 01 A / g. It can be seen from the figure that after cycling 1000 times at a current density of 1 A / g, the modified multi-layer Ti3C2T x -b still maintains a reversible specific capacity of 314.78 mAh / g. While the specific capacity of the modified single-layer Ti3C2T x -b is only 150.71 mAh / g after 1000 cycles. And it can be seen that the modified multi-layer Ti3C2T x -b maintains a relatively stable charge-discharge efficiency throughout the entire cycle, while the charge-discharge efficiency of the modified single-layer Ti3C2T x -b is not so stable.

[0081] Figure 6 For the rate performance test of the modified multi-layer Ti3C2T x -b in Example 1. It can be seen from the figure that regardless of the current density, the Ti3C2T x -b x material maintains a relatively stable discharge specific capacity, indicating that the coated Ti3C2T x -b has good rate performance.

[0082] Figure 7 For the AC impedance spectra of the multi-layer Ti3C2T x before and after modification in Example 1. It can be seen from the figure that in the high-frequency region, Ti3C2T x -b shows a smaller diffusion impedance and a faster ion diffusion rate in the low-frequency region.

[0083] Figure 8 For the SEM image of the modified single-layer Ti3C2T x -b in Comparative Example 2. It can be seen from the figure that the modified single-layer Ti3C2T x is also coated with ferrocene, but the thickness and density of its coating layer are far less than those of the modified multi-layer Ti3C2T x -b. This may be due to the insufficient electrostatic attraction generated by the negatively charged functional groups on its surface.

[0084] Figure 9Fig. 0 shows the charge-discharge cycling curves of Example 1 and Comparative Example 3 at a current density of 0.1 A / g. It can be seen that the specific capacity of the modified multi-layer Ti3C2T x -b treated with DMF is much higher than that treated with DMAC. And when the current density is increased to 1 A / g, the modified multi-layer Ti3C2T x -b treated with DMAC has almost no specific capacity.

[0085] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method to improve the performance of multilayer Ti3C2T x The method for modifying the specific capacity by encapsulation is characterized in that: The following steps are involved: Multilayer Ti3C2T was prepared using HF solution and Ti3AlC2 as raw materials. x ; Dissolve 1,1-dicarboxyferrocene and a cobalt source in an organic solvent, mix thoroughly, and then add the multilayer Ti3C2T x , heated and stirred for 12 h, centrifuged, precipitated, and vacuum dried to obtain the encapsulated modified Ti3C2T x ; The organic solvent is N,N-dimethylformamide.

2. The method for improving the multilayer Ti3C2T according to claim 1 x The method for modifying the specific capacity by encapsulation is characterized in that: The multilayer Ti3C2T x The specific steps of the preparation method are as follows: adding Ti3AlC2 to HF solution at 25-35°C and stirring for 5-7h, centrifuging and drying the obtained mixed solution to obtain multilayer Ti3C2T x .

3. The method for improving the multilayer Ti3C2T according to claim 2 x The method for modifying the specific capacity by encapsulation is characterized in that: The amount ratio of the Ti3AlC2 and HF solution is 1g:20mL; and / or The process of adding Ti3AlC2 into the HF solution is completed within 3-5 minutes; and / or The centrifugal conditions are: centrifugation at 5000 rpm for 5 min; and / or The drying conditions are: vacuum drying at 60-80°C for 6-12h.

4. The method for improving the multilayer Ti3C2T according to claim 1 x The method for modifying the specific capacity by encapsulation is characterized in that: 1,1 dicarboxyferrocene, cobalt source, organic solvent and multilayer Ti3C2T x The dosage ratio is 1.2mmol:1.1mmol:50mL:0.2g.

5. The method for improving the multilayer Ti3C2T according to claim 4 x The method for modifying the specific capacity by encapsulation is characterized in that: The cobalt source is selected from one of Co(NO3)2·6H2O, CoCl2 and CoSO4.

6. The method for improving the multilayer Ti3C2T according to claim 1 x The method for modifying the specific capacity by encapsulation is characterized in that: The heating and stirring conditions are: reacting at 120° C. for 12 hours; and / or The centrifugal conditions are: centrifugation at 5000 rpm for 5 min; and / or The drying conditions are: vacuum drying at 60° C. for 12 h.

7. A modified multilayer Ti3C2T obtained by the encapsulation modification method according to any one of claims 1 to 6 x .

8. A modified multilayer Ti3C2T as claimed in claim 7 x Application in battery preparation.

9. A battery electrode, characterized in that: The raw material includes the modified multilayer Ti3C2T x .

10. A lithium ion battery, characterized in that: Comprising the battery electrode as claimed in claim 9.

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