A mxene composite material and a preparation method and application thereof

Abstract

The application belongs to the technical field of battery materials, and discloses a MXene composite material and a preparation method and application thereof.The MXene composite material comprises a phosphorus-doped Bi2Te3 / MXene material.The MXene composite material is doped with phosphorus, the doping of phosphorus atoms can introduce tellurium vacancies for Bi2Te3, and the introduction of bismuth telluride can effectively improve the specific surface area of the material, increase the active sites of potassium ions, and the unique layered structure of the MXene material can effectively relieve the pressure increase caused by the volume expansion of the negative electrode material due to the large size of potassium ions, thereby improving the electrochemical performance of the potassium ion battery.The MXene composite material greatly reduces the negative electrode volume expansion phenomenon occurring during the potassium ion extraction and embedding, and when applied as a negative electrode in a potassium ion battery, greatly improves the specific capacity and cycle stability of the potassium ion battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery materials, and particularly relates to a MXene composite material and a preparation method and application thereof. BACKGROUND

[0002] Lithium ion batteries currently dominate the energy storage field, and have advantages such as high energy density and long cycle life. However, with the increasing demand for energy storage, the limited resources, uneven distribution and high cost of lithium mines limit the development of lithium ion batteries. Therefore, people have begun to study new secondary alkali metal batteries that can replace lithium ion batteries.

[0003] Potassium resources are abundant, low in price, and have advantages such as a standard electrode potential close to that of lithium (K + about 2.93V, Li + about 3.04V) and the like, and potassium ion batteries have a similar 'rocking chair' working mechanism to lithium ion batteries. Therefore, under the condition that the development of lithium ion batteries is limited by multiple factors such as lithium mine resources and high cost, and the demand for energy storage is increasing, potassium ion batteries have attracted people's attention and become a potential replacement for lithium ion batteries. However, due to the larger radius of potassium ions Potassium ions are prone to cause huge volume expansion of the negative electrode during the cycle process, thereby resulting in poor electrochemical performance of the potassium ion battery. Therefore, it is necessary to develop a negative electrode material suitable for potassium ion batteries.

[0004] MXene material is a new type of two-dimensional material composed of transition metal M, group IIIA or group IVA element A and carbon and / or nitrogen element X. The preparation process of MXene material usually involves etching the A atomic layer with hydrofluoric acid to form a nanosheet material with functional groups such as hydroxyl, oxygen and fluorine. MXene material has multiple chemical compositions and rich functional groups, and has excellent mechanical properties and good electrical conductivity. In the field of energy storage, MXene material shows great potential. However, if MXene material is directly used as a potassium ion negative electrode material, the volume expansion of the negative electrode is large, resulting in poor cycle performance of the potassium ion battery, and the specific capacity is also low.

[0005] Since the performance of common potassium battery negative electrode materials cannot meet the requirements of practical applications, it is necessary to prepare potassium battery negative electrode materials with high performance and long service life. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a MXene composite material and a preparation method and application thereof. The MXene composite material according to the present application is obtained by growing Bi2Te3 on MXene material nanosheets. The growth of Bi2Te3 can expand the distance between the layers of the MXene material, prevent the stacking of the layers of the MXene material, thereby increasing the specific surface area thereof. The MXene composite material is doped with phosphorus. The doping of phosphorus atoms can introduce tellurium vacancies in Bi2Te3. The introduction of bismuth telluride can effectively increase the specific surface area of the material and increase the active sites of potassium ions. The unique layered structure of the MXene material can effectively alleviate the volume expansion of the negative electrode material caused by the large size of potassium ions, thereby improving the electrochemical performance of the potassium ion battery. The MXene composite material according to the present application greatly reduces the volume expansion of the negative electrode caused by the extraction and embedding of potassium ions. When used as a negative electrode in a potassium ion battery, the MXene composite material greatly improves the specific capacity and cycle stability of the potassium ion battery.

[0007] The first aspect of the present application provides a MXene composite material.

[0008] The MXene composite material comprises phosphorus-doped Bi2Te3 / MXene material. Bi2Te3 is loaded on the MXene material and is doped with phosphorus.

[0009] Preferably, in the MXene composite material, the doping amount of phosphorus is 0.1-20wt%; preferably 0.5-15wt%; further preferably 1.5-10wt%, 1.5-5wt% or 5-9wt%.

[0010] Preferably, the specific surface area of the MXene composite material is 95-118m 2 / g; further preferably, the specific surface area of the MXene composite material is 97.4-114.2m 2 / g.

[0011] The second aspect of the present application provides a preparation method of a MXene composite material.

[0012] Specifically, the preparation method of the MXene composite material comprises the following steps:

[0013] (1) mixing a non-ionic polymer compound, an alkali, a telluride, a MXene material and a solvent, heating under an inert gas atmosphere, then adding hydrazine hydrate, and reacting to obtain a mixture;

[0014] (2) adding a bismuth salt to the mixture, reacting, and separating to obtain a Bi2Te3 / MXene material;

[0015] (3) placing the phosphorus source and the Bi2Te3 / MXene material in a reaction device, then introducing an inert gas, heating and keeping warm to obtain the MXene composite material.

[0016] Preferably, in step (1), the weight ratio of the non-ionic high molecular compound, the base, the telluride and the MXene material is 0.1-0.8:(0.3-1.8):(0.1-1):0.05; preferably the weight ratio is 0.2-0.5:(0.6-1.5):(0.3-0.8):0.05.

[0017] Preferably, in step (1), the amount ratio of the MXene material to the solvent is 0.05-0.1 g:10-60 mL, preferably 0.05-0.1 g:20-40 mL.

[0018] Preferably, in step (1), the non-ionic high molecular compound includes polyvinylpyrrolidone (PVP).

[0019] Preferably, in step (1), the base is selected from sodium hydroxide or potassium hydroxide.

[0020] Preferably, in step (1), the telluride is an oxide of tellurium, preferably tellurium dioxide (TeO2).

[0021] Preferably, in step (1), the MXene material is selected from Ti3C2 and / or Ti3N2.

[0022] Further preferably, the surface of the MXene material further contains functional groups -O, -F or -OH.

[0023] Preferably, in step (1), the solvent is an alcohol solvent, preferably ethylene glycol.

[0024] Preferably, in step (1), the inert gas is nitrogen or argon.

[0025] Preferably, the flow rate of the inert gas is 50-200 mL / min, preferably 70-200 mL / min.

[0026] Preferably, in step (1), the heating temperature is 110-200°C, preferably 130-200°C. The heating mode is oil bath heating.

[0027] Preferably, in step (1), the reaction time is 0.5-3 hours, preferably 1-3 hours. The reaction temperature is 110-200°C.

[0028] Preferably, in step (2), the bismuth salt is bismuth nitrate or bismuth nitrate hydrate.

[0029] Preferably, in step (2), the bismuth salt is mixed with the solvent before being added; further preferably, 40-80 mg of bismuth salt is dissolved in 10-20 mL of ethylene glycol, mixed, and then added.

[0030] Preferably, in step (2), the reaction time is 0.5-3 hours, preferably 1-3 hours. The reaction temperature is 110-200℃.

[0031] Preferably, in step (2), the flow rate of the inert gas during the reaction is 90-200 mL / min, for example 150 mL / min.

[0032] Preferably, in step (2), the separation process is to collect the solution after the reaction, centrifuge and wash multiple times, and dry at 60-80℃ under vacuum for 10-12 hours to obtain the Bi2Te3 / MXene material.

[0033] Preferably, in step (3), the weight ratio of the phosphorus source to the Bi2Te3 / MXene material is 0.5-8:1, and the weight ratio is preferably 1-5:1.

[0034] Preferably, in step (3), the phosphorus source and the Bi2Te3 / MXene material are added to two quartz boats, which are placed in a tube furnace. The quartz boat containing the phosphorus source is placed on the gas inlet side of the tube furnace, and the quartz boat containing the Bi2Te3 / MXene material is placed on the gas outlet side of the tube furnace.

[0035] Preferably, in step (3), the phosphorus source is at least one of potassium dihydrogen phosphate and sodium dihydrogen phosphate, and the mass purity of the phosphorus source is preferably 99.99%.

[0036] Preferably, in step (3), the flow rate of the inert gas is 70-200 mL / min, preferably 90-200 mL / min.

[0037] Preferably, in step (3), the temperature of the heating is 280-450℃, preferably 300-450℃.

[0038] Preferably, in step (3), the heating rate is 2-8℃ / min, preferably 3-7℃ / min.

[0039] Preferably, in step (3), the holding time is 2-7 hours, preferably 3-7 hours. After the holding time ends, the temperature is naturally cooled to room temperature.

[0040] The third aspect of the present application provides an application of the MXene composite material.

[0041] A kind of potassium ion battery, including negative electrode, positive electrode, electrolyte, diaphragm;The negative electrode includes the above-mentioned MXene composite material.I.e.the MXene composite material as active material in negative electrode.

[0042] Preferably, the negative electrode further includes conductive agent and adhesive.

[0043] Preferably, the mass ratio of the MXene composite material, conductive agent and adhesive is (6-11) :(1-3) :1, preferably 7:2:1.

[0044] The preparation method of the negative electrode is as follows: the MXene composite material is mixed with conductive carbon black and adhesive in a ratio (mass ratio) of (6-11) :(1-3) :1, N-methylpyrrolidone (NMP) solvent is added for mixing, a slurry is prepared, then the slurry is uniformly coated on a copper foil, dried in a vacuum drying box, and sliced using a slicer to prepare the negative electrode.

[0045] Preferably, the positive electrode is potassium sheet.

[0046] Preferably, the electrolyte is 0.6-0.8 mol / L KPF6, and the solvent in the electrolyte is ethylene carbonate and diethyl carbonate in a volume ratio of 1:1.

[0047] Compared with the prior art, the present application has the following advantages:

[0048] (1) The MXene composite material of the present application is Bi2Te3 grown on MXene material nanosheet, the growth of Bi2Te3 can expand the distance between the layers of MXene material, prevent the interlayer stacking of MXene material, thereby increasing its specific surface area, and the MXene composite material is doped with phosphorus, the doping of phosphorus atoms can introduce tellurium vacancies for Bi2Te3, and the introduction of bismuth telluride can effectively increase the specific surface area of the material, increase the active sites of potassium ions, and the unique layered structure of MXene material can effectively relieve the pressure increase caused by the volume expansion of the negative electrode material due to the large size of potassium ions, thereby improving the electrochemical performance of the potassium ion battery. The MXene composite material of the present application greatly reduces the negative electrode volume expansion phenomenon occurring during potassium ion extraction and insertion, and as a negative electrode applied in a potassium ion battery, greatly improves the specific capacity and cycle stability of the potassium ion battery.

[0049] (2) The preparation method of the present application is simple, safe and environmentally friendly, and is suitable for large-scale production and use. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a scanning electron microscope image of the MXene composite material in Example 1 of the present application.

[0051] Figure 2A cycle performance graph of the MXene composite material in Example 1 of the present application as a working electrode of a potassium ion half battery at a current density of 200 mA / g;

[0052] Figure 3 A cycle performance graph of the Bi2Te3 / MXene material without phosphorus doping in Comparative Example 1 as a working electrode of a potassium ion half battery at a current density of 200 mA / g;

[0053] Figure 4 A cycle performance graph of the Bi2Te3 material in Comparative Example 2 as a working electrode of a potassium ion half battery at a current density of 200 mA / g. DETAILED DESCRIPTION

[0054] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0055] The raw materials, reagents or devices used in the following examples, if not specifically stated, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0056] Example 1

[0057] A preparation method of a MXene composite material, comprising the following steps:

[0058] (1) 0.2 g of polyvinylpyrrolidone (PVP), 0.6 g of sodium hydroxide (NaOH), 0.3 g of tellurium dioxide (TeO2) and 0.05 g of MXene material (Ti3C2) are dissolved in 20 mL of ethylene glycol solution, then poured into a three-necked flask, using nitrogen (N2) as a protective gas, the mixed liquid is heated to 160℃ using an oil bath;

[0059] (2) 2 mL of hydrazine hydrate is added to the above mixture, and the reaction is carried out for 1 hour;

[0060] (3) 40 mg of bismuth nitrate pentahydrate is dissolved in 10 mL of ethylene glycol, and added to the mixture of step (2) and reacted for 1 hour, then the solution is collected and centrifuged for 5 times, and dried at 60℃ under vacuum for 12 hours to obtain a Bi2Te3 / MXene material;

[0061] (4) The Bi2Te3 / MXene material and the phosphorus source (potassium dihydrogen phosphate) are added to two quartz boats respectively according to a mass ratio of 1:4;

[0062] (5) The two quartz boats are placed in a tube furnace, wherein the quartz boat containing the phosphorus source is located at the gas inlet side of the tube furnace, and the quartz boat containing the Bi2Te3 / MXene material is located at the gas outlet end of the tube furnace;

[0063] (6) heating at a temperature increasing rate of 5℃ / min to 300℃ under the protection of inert (N2) gas with a gas flow rate of 90mL / min, and naturally cooling to room temperature 25℃ after keeping for 4 hours;

[0064] (7) collecting the solid powder in the quartz boat on the gas outlet side to obtain the MXene composite material.

[0065] A potassium ion half battery comprises a working electrode, a counter electrode, an electrolyte and a separator.

[0066] The working electrode is prepared by mixing the MXene composite material prepared in the embodiment, conductive carbon black and a binder in a ratio (mass ratio) of 7:2:1, adding N-methyl pyrrolidone (NMP) solvent for mixing, uniformly coating on a copper foil, drying in a vacuum drying box, and slicing to obtain the working electrode;

[0067] The counter electrode is a potassium sheet;

[0068] The electrolyte is 0.6-0.8mol / L KPF6, and the solvent in the electrolyte is ethylene carbonate and diethyl carbonate in a volume ratio of 1:1;

[0069] The separator is a glass fiber membrane;

[0070] The working electrode, the counter electrode, the electrolyte and the separator are assembled to obtain the potassium ion half battery.

[0071] The MXene composite material prepared in the embodiment is a phosphorus-doped Bi2Te3 / MXene material, and the specific surface area of the MXene composite material is 114.2m 2 / g, which is much larger than the specific surface area (35.2m 2 / g) of the original Bi2Te3.

[0072] The specific capacity of the above potassium ion half battery after 100 cycles at a current density of 200mA / g is 332.9mAh / g, which is 1.29 times the specific capacity (258.6mAh / g) of the Bi2Te3 / MXene material without phosphorus doping as the working electrode of the potassium ion half battery, and 2.3 times the specific capacity (144.7mAh / g) of the original Bi2Te3 as the working electrode of the potassium ion half battery.

[0073] Embodiment 2

[0074] A preparation method of a MXene composite material comprises the following steps:

[0075] (1) 0.3 g of polyvinylpyrrolidone (PVP), 0.7 g of sodium hydroxide (NaOH), 0.4 g of tellurium dioxide (TeO2) and 0.05 g of MXene material (Ti3N2) were dissolved in 20 mL of ethylene glycol solution, and then poured into a three-necked flask. Nitrogen (N2) was used as a protective gas, and the mixed liquid was heated to 150°C using an oil bath;

[0076] (2) 2 mL of hydrazine hydrate was added to the above mixture, and the reaction was carried out for 1 hour;

[0077] (3) After 40 mg of bismuth nitrate pentahydrate was dissolved in 10 mL of ethylene glycol and added to the mixture of step (2) and reacted for 1 hour, the solution was collected and centrifuged and washed 3 times, and dried at 60°C under vacuum for 12 hours to obtain a Bi2Te3 / MXene material;

[0078] (4) The Bi2Te3 / MXene material and the phosphorus source (potassium dihydrogen phosphate) were added to two quartz boats in a mass ratio of 1:2, respectively;

[0079] (5) The two quartz boats were placed in a tube furnace, wherein the quartz boat containing the phosphorus source was placed at the gas inlet side of the tube furnace, and the quartz boat containing the Bi2Te3 / MXene material was placed at the gas outlet side of the tube furnace;

[0080] (6) Under the protection of inert (N2) gas with a gas flow rate of 110 mL / min, the temperature was raised to 300°C at a rate of 5°C / min, and after holding for 4 hours, it was naturally cooled to room temperature 25°C;

[0081] (7) The solid powder in the quartz boat at the gas outlet side was collected, and the MXene composite material was obtained.

[0082] A potassium ion half-cell was prepared according to the same method as in Example 1, except that the MXene composite material prepared in this example was used instead of the MXene composite material in Example 1.

[0083] The MXene composite material prepared in this example is a phosphorus-doped Bi2Te3 / MXene material, and the specific surface area of the MXene composite material is 109.3 m 2 / g, which is much larger than the specific surface area of the original Bi2Te3 (35.2 m 2 / g).

[0084] The specific capacity of the above potassium ion half battery after 100 cycles at a current density of 200 mA / g is 312.3 mAh / g, which is 1.21 times the specific capacity (258.6 mAh / g) of the Bi2Te3 / MXene material without phosphorus doping as the working electrode of the potassium ion half battery and 2.16 times the specific capacity (144.7 mAh / g) of the original Bi2Te3 as the working electrode of the potassium ion half battery.

[0085] Example 3

[0086] A method for preparing a MXene composite material, comprising the following steps:

[0087] (1) 0.2 g of polyvinylpyrrolidone (PVP), 0.6 g of sodium hydroxide (NaOH), 0.3 g of tellurium dioxide (TeO2), and 0.05 g of MXene material (Ti3C2) are dissolved in 20 mL of ethylene glycol solution, then poured into a three-necked flask, nitrogen (N2) is used as the protective gas, and the mixed liquid is heated to 140°C using an oil bath;

[0088] (2) 2 mL of hydrazine hydrate is added to the above mixture, and the reaction is carried out for 1 hour;

[0089] (3) 40 mg of bismuth nitrate pentahydrate is dissolved in 10 mL of ethylene glycol, then added to the mixture of step (2) and reacted for 1 hour, then the solution is collected and centrifuged for 4 times, and dried at 60°C under vacuum for 12 hours to obtain a Bi2Te3 / MXene material;

[0090] (4) The Bi2Te3 / MXene material and the phosphorus source (sodium dihydrogen phosphate) are added to two quartz boats in a mass ratio of 1:1, respectively;

[0091] (5) The two quartz boats are placed in a tube furnace, wherein the quartz boat containing the phosphorus source is located at the gas inlet side of the tube furnace, and the quartz boat containing the Bi2Te3 / MXene material is located at the gas outlet side of the tube furnace;

[0092] (6) Under the protection of inert (N2) gas with a flow rate of 120 mL / min, the temperature is raised to 300°C at a rate of 5°C / min, and after holding for 4 hours, it is naturally cooled to room temperature 25°C;

[0093] (7) The solid powder in the quartz boat at the gas outlet side is collected, and the MXene composite material is obtained.

[0094] A potassium ion half battery, the preparation method of the potassium ion half battery is the same as that of Example 1, the difference is only that the MXene composite material prepared in this embodiment is used instead of the MXene composite material in Example 1.

[0095] The MXene composite material prepared in the embodiment is a phosphorus-doped Bi2Te3 / MXene material, and the specific surface area of the MXene composite material is 97.4 m 2 / g, which is much larger than the specific surface area (35.2 m 2 / g) of the original Bi2Te3.

[0096] The specific capacity of the above potassium ion half battery after 100 cycles at a current density of 200 mA / g is 278.6 mAh / g, which is 1.08 times the specific capacity (258.6 mAh / g) of the Bi2Te3 / MXene material without phosphorus doping as the working electrode of the potassium ion half battery and 1.93 times the specific capacity (144.7 mAh / g) of the original Bi2Te3 as the working electrode of the potassium ion half battery.

[0097] Comparative Example 1

[0098] A method for preparing a Bi2Te3 / MXene material without phosphorus doping includes the following steps:

[0099] (1) 0.2 g of polyvinylpyrrolidone (PVP), 0.6 g of sodium hydroxide (NaOH), 0.3 g of tellurium dioxide (TeO2), and 0.05 g of MXene material (Ti3C2) were dissolved in 20 mL of ethylene glycol solution, and then poured into a three-necked flask. Nitrogen (N2) was used as a protective gas, and the mixed liquid was heated to 160°C using an oil bath;

[0100] (2) 2 mL of hydrazine hydrate was added to the above mixture, and the reaction was carried out for 1 hour;

[0101] (3) After 40 mg of bismuth nitrate pentahydrate was dissolved in 10 mL of ethylene glycol and added to the mixture of step (2) and reacted for 1 hour, the solution was collected, centrifuged and washed 5 times, and dried at 60°C under vacuum for 12 hours to obtain a Bi2Te3 / MXene material.

[0102] The specific surface area of the Bi2Te3 / MXene material prepared in the comparative example is 87.3 m 2 / g, which is greater than the specific surface area (35.2 m 2 / g) of the original Bi2Te3.

[0103] According to the method of Example 1, the Bi2Te3 / MXene material prepared in the comparative example was used as the working electrode of the potassium ion half battery, and the specific capacity of the obtained potassium ion half battery after 100 cycles at a current density of 200 mA / g was 258.6 mAh / g.

[0104] Comparative Example 2

[0105] A preparation method of a Bi2Te3 material, comprising the following steps:

[0106] (1) 0.2 g of polyvinylpyrrolidone (PVP), 0.6 g of sodium hydroxide (NaOH), and 0.3 g of tellurium dioxide (TeO2) were dissolved in 20 mL of ethylene glycol solution, and then poured into a three-necked flask. Nitrogen (N2) was used as a protective gas, and the mixed liquid was heated to 160°C using an oil bath;

[0107] (2) 2 mL of hydrazine hydrate was added to the above mixture, and reacted for 1 hour;

[0108] (3) After 40 mg of bismuth nitrate pentahydrate was dissolved in 10 mL of ethylene glycol and added to the mixture of step (2) and reacted for 1 hour, the solution was collected, centrifuged and washed 5 times, and dried at 60°C under vacuum for 12 hours to obtain a Bi2Te3 material.

[0109] The specific surface area of the Bi2Te3 material prepared in this comparative example was 35.2 m 2 / g.

[0110] According to the method of Example 1, the Bi2Te3 material prepared in this comparative example was used as the working electrode of the potassium ion half-cell, and the specific capacity of the obtained potassium ion half-cell after 100 cycles at a current density of 200 mA / g was 144.7 mAh / g.

[0111] Product effect test

[0112] The performance of the materials prepared in Examples 1-3 and Comparative Examples 1-2, and the specific capacity of the corresponding potassium ion half-cell working electrode after 100 cycles at a current density of 200 mA / g are shown in Table 1.

[0113] Table 1

[0114]

[0115] As can be seen from Table 1, the specific surface area of the MXene composite material prepared in Examples 1-3 is significantly larger than that of Comparative Examples 1-2, and the specific capacity of the potassium ion half-cell prepared from the MXene composite material prepared in Examples 1-3 after 100 cycles at a current density of 200 mA / g is also significantly larger than that of Comparative Examples 1-2.

[0116] Figure 1 SEM image of the MXene composite material in Example 1 of the present application; Figure 2 Cycle performance graph of the MXene composite material in Example 1 of the present application as the working electrode of the potassium ion half-cell at a current density of 200 mA / g; Figure 3The cycle performance diagram of the Bi2Te3 / MXene material without doping phosphorus in Comparative Example 1 as a working electrode of a potassium ion half-battery at a current density of 200 mA / g; Figure 4 The cycle performance diagram of the Bi2Te3 material in Comparative Example 2 as a working electrode of a potassium ion half-battery at a current density of 200 mA / g.

[0117] From Figure 1 It can be seen that the MXene composite material prepared in Example 1 has a larger interlayer spacing.

[0118] From Figures 2-4 It can be seen that the MXene composite material prepared in Example 1 has a larger interlayer spacing.

Claims

1. A MXene composite material, characterized in that, The MXene composite material comprises a phosphorus-doped Bi2Te3 / MXene material; The MXene composite material is prepared by the following steps: (1) mixing a non-ionic polymer compound, a base, a telluride, a MXene material, and a solvent, then pouring into a three-necked flask, heating under an inert gas atmosphere, then adding hydrazine hydrate, and reacting to obtain a mixture; (2) adding a bismuth salt to the mixture, reacting, and separating to obtain a Bi2Te3 / MXene material; (3) placing a phosphorus source and the Bi2Te3 / MXene material in a reaction device, then passing an inert gas, warming, and keeping warm to obtain the MXene composite material; In step (1), the non-ionic polymer compound comprises polyvinylpyrrolidone; and the telluride is an oxide of tellurium. In step (3), the phosphorus source and the Bi2Te3 / MXene material are respectively added into two quartz boats, and the two quartz boats are placed in a tube furnace, wherein the quartz boat containing the phosphorus source is located at the gas inlet side of the tube furnace, and the quartz boat containing the Bi2Te3 / MXene material is located at the gas outlet end of the tube furnace.

2. The MXene composite of claim 1, wherein, In the MXene composite material, the doping amount of phosphorus is 0.1-20wt%.

3. The MXene composite of claim 1, wherein, The specific surface area of the MXene composite is 95-118 m 2 / g.

4. The MXene composite of claim 1, wherein, In step (1), the weight ratio of the non-ionic polymer compound, the base, the telluride, and the MXene material is 0.1-0.8: (0.3-1.8): (0.1-1): 0.

05.

5. The MXene composite of claim 1, wherein, In step (1), the base is selected from sodium hydroxide or potassium hydroxide; and the MXene material is selected from Ti3C2 and / or Ti3N2.

6. The MXene composite of claim 1, wherein, In step (1), the heating temperature is 110-200℃.

7. The MXene composite of claim 1, wherein, In step (2), the bismuth salt is bismuth nitrate or bismuth nitrate hydrate; and in step (2), the reaction time is 0.5-3 hours, and the reaction temperature is 110-200℃.

8. The MXene composite of claim 7, wherein, In step (2), the reaction time is 1-3 hours.

9. The MXene composite of claim 1, wherein, In step (3), the weight ratio of the phosphorus source and the Bi2Te3 / MXene material is 0.5-8:

1.

10. A potassium-ion battery, characterized in that, The battery comprises a negative electrode, a positive electrode, an electrolyte, and a separator; and the negative electrode comprises the MXene composite material according to any one of claims 1-9.

Images