MXene / h-moo3 electrode material for zinc ion battery and preparation method and application thereof

Abstract

The application relates to the field of electrochemistry, in particular to an MXene / h-MoO3 electrode material for a zinc ion battery and a preparation method and application thereof. x The preparation method comprises the following steps: preparing Ti3C2T x MXene material; the prepared liquid MXene is dropped into an ammonium molybdate and formic acid mixed solution, a uniform solution is obtained through ultrasonic stirring, the solid after centrifugation is washed with deionized water for multiple times, and MXene / h-MoO3 is obtained after drying. In the application, MXene is used as a framework, the active sites are more, the application in a zinc ion battery significantly improves the electrochemical performance, the prepared MXene / h-MoO3 composite material combines the advantages of MXene and h-MoO3, has good conductive performance, excellent electrochemical performance and strong overall stability, and the preparation process is simple and safe, and the application is expected to be widely applied in electrode materials of zinc ion batteries and even other energy storage devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemistry, in particular to a MXene / h-MoO3 electrode material for zinc ion batteries and a preparation method and application thereof. BACKGROUND

[0002] Zinc ion batteries are a new type of rechargeable batteries based on the storage and release of zinc ions. Compared with traditional lithium ion batteries, zinc ion batteries have higher energy density, lower cost and better safety performance. Zinc ion batteries have many significant advantages. Zinc material is relatively cheap and abundant, so the manufacturing cost of zinc ion batteries is low. Secondly, zinc ion batteries have higher energy density and can provide longer battery life. In addition, zinc ion batteries have better safety performance and are not prone to overheating or fire. Zinc ions have potential applications in many fields. First, it can be used as a battery for portable electronic devices, electric vehicles and energy storage systems. Because zinc ion batteries have lower cost and higher energy density, they can provide longer use time and higher performance. Secondly, zinc ion batteries can be used for renewable energy storage. Zinc ion batteries can store solar and wind energy and release them when needed, thereby balancing power supply and demand. In addition, zinc ion batteries can also be used for emergency power supplies and wireless sensor networks and other special applications. However, zinc ion batteries also have some challenges and problems, such as high manufacturing cost, difficulty in controlling the micro-morphology of electrode materials, poor stability, etc. Further research and development are needed to improve the performance and stability of zinc ion batteries. SUMMARY

[0003] The present application provides a MXene / h-MoO3 electrode material for zinc ion batteries and a preparation method and application thereof. The present application first etches titanium aluminum carbide with hydrochloric acid and lithium fluoride to obtain ultra-thin Ti3C2T x nanosheets, and then prepares a MXene / h-MoO3 composite material. The prepared MXene / h-MoO3 composite material combines the advantages of MXene and h-MoO3, has good conductivity, excellent electrochemical performance, and strong overall stability, and the preparation process is simple, has low energy consumption, and the process is safer. The present application provides a new idea and method for producing MXene-based electrode materials with good electrical properties, which is expected to be widely used in zinc ion battery electrode materials and even other energy storage devices.

[0004] In order to achieve the above application purposes, the present application adopts the following technical solutions:

[0005] The present application provides a preparation method of a MXene / h-MoO3 electrode material for zinc ion batteries, comprising the following steps:

[0006] (1) preparing Ti3C2T x MXene material;

[0007] (2) preparing MXene / h-MoO3 material:

[0008] The liquid-state MXene prepared in step (1) is dropped into an ammonium molybdate and formic acid mixed solution, and a uniform solution is obtained by ultrasonic stirring, and the solid after centrifugation is washed with deionized water for multiple times, and MXene / h-MoO3 is obtained after drying.

[0009] In the above technical solution, further, the mass ratio of the MXene, ammonium molybdate and formic acid is 0.5-1.5:1:1-1.2.

[0010] In the above technical solution, further, step (1) prepares Ti3C2T x The method for preparing the MXene material is: lithium fluoride is dissolved in a hydrochloric acid solution, stirring, adding titanium aluminum carbide, water bath stirring, centrifuging in a centrifuge, washing with hydrochloric acid and then continuing to wash with deionized water, then performing ultrasonic ice water bath for 1h, and then continuing to centrifuge to obtain ultra-thin Ti3C2T x nanosheets.

[0011] In the above technical solution, further, the mass ratio of the titanium aluminum carbide, lithium fluoride and hydrochloric acid is 5:6-10:110-120; and the concentration of the hydrochloric acid solution is 11-13 mol / L. -1 .

[0012] In the above technical solution, further, the water bath stirring temperature is 40-50℃; the water bath stirring time is 46-50h; and the ultrasonic ice water bath time is 0.8-1.2h.

[0013] In the above technical solution, further, the centrifuge speed is 3500-4000rpm; and the deionized water washing solution pH is 6-7.

[0014] In the above technical solution, further, in step (2), the ultrasonic stirring time is 0.8-1.2h, and the ultrasonic reaction temperature is 50-70℃.

[0015] In the above technical solution, further, in step (2), the centrifuge speed is 3500-4000rpm; and the drying temperature is 60-80℃.

[0016] The application also provides a MXene / h-MoO3 electrode material, which is prepared by any one of the above methods.

[0017] The application also provides application of the aforementioned MXene / h-MoO3 electrode material in a zinc ion battery.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] (1) The application selects MXene as a precursor, and the raw material source is extensive and the cost is low, so that the preparation cost of the zinc ion battery can be significantly reduced, and the long-term goal of green environmental protection and sustainable development is met. Meanwhile, the MXene has a porous structure, and the prepared MXene contains rich macropores, mesopores and micropores, and has a large specific surface area, so that the overall performance of the electrode material prepared from the MXene is relatively excellent compared with other two-dimensional materials.

[0020] (2) The application prepares the MXene / h-MoO3 composite material, and the method is simple, the energy consumption is low, and the microstructure, particle size distribution and dispersity can be easily controlled.

[0021] (3) The MXene / h-MoO3 composite material prepared by the application combines the advantages of high specific capacitance of the transition metal compound and excellent conductivity of the MXene, the h-MoO3 can significantly improve the stacking condition between the MXene nanolayers, effectively improve the microstructure, and is beneficial to improving the electrochemical performance and cycle stability of the composite electrode material. The h-MoO3 provides a pseudo-capacitance, has good electrochemical reaction activity, and has high specific capacitance, so that the h-MoO3 and the MXene can be combined to fully combine the advantages of both. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an X-ray diffraction pattern of the MXene / h-MoO3 composite material prepared in Example 1 as an electrode material.

[0023] Figure 2 is a scanning electron microscope pattern of the MXene / h-MoO3 composite material prepared in Example 1 as an electrode material.

[0024] Figure 3 is a cyclic voltammogram of the MXene / h-MoO3 prepared in Example 1 as an electrode material in a 2 mol·L -1 Zn(OTF)2 electrolyte at different scanning speeds.

[0025] Figure 4 is a constant current charge-discharge curve of the MXene / h-MoO3 composite material prepared in Example 1 as an electrode material in a 2 mol·L -1 Zn(OTF)2 electrolyte at different current densities.

[0026] Figure 5is the AC impedance diagram of the MXene / h-MoO3 composite material prepared in Example 1 as an electrode material in a 2 mol·L -1 of Zn(OTF)2 electrolyte.

[0027] Figure 6 is the cycle performance and coulombic efficiency of the device of the MXene / h-MoO3 composite material prepared in Example 1 as an electrode material in a 2 mol·L -1 of Zn(OTF)2 electrolyte after 1000 cycles. DETAILED DESCRIPTION

[0028] The following examples are provided to better further understand the present application, and are not limited to the best mode, and do not limit the content and scope of protection of the present application, and any person under the inspiration of the present application or the combination of the present application with other prior art features, any product identical or similar to the present application falls within the scope of protection of the present application.

[0029] The specific experimental steps or conditions in the examples are operated or conditions according to the conventional experimental steps described in the literature in the art. The reagents or instruments used without specifying the manufacturer are conventional reagents that can be obtained by market purchase.

[0030] In order to more intuitively disclose the technical scheme of the present application and highlight the beneficial effects of the present application, the electrochemical performance of the present application based on MXene / h-MoO3 is described in combination with specific embodiments.

[0031] Example 1

[0032] The MXene / h-MoO3 sample material is prepared, including the following steps:

[0033] (1) Preparation of MXene material: take lithium fluoride 1.6 g, 12 M hydrochloric acid 20 ml, stirring for 15 min, add 1 g titanium aluminum carbide, 45℃ water bath stirring for 48 h; the sample after stirring is put into the centrifuge 4000 rpm, washed with 2M hydrochloric acid and then with deionized water to neutral; after washing, the obtained sample is subjected to ultrasonic ice water bath for 1 h; the sample is centrifuged for 1 h to obtain liquid ultrathin Ti3C2T x nanosheet;

[0034] (2) Preparation of MXene / h-MoO3: The liquid MXene obtained in the above step was dropped into a mixed solution of ammonium molybdate and formic acid using a rubber bulb dropper, and a uniform solution was obtained by stirring at 60°C for 1h, 100mg of MXene, 100mg of ammonium molybdate, and 100mg of formic acid. The solid after centrifugation was washed with deionized water several times, and dried at 80°C to obtain a MXene / h-MoO3 sample.

[0035] The electrode preparation method of MXene / h-MoO3 for zinc ion batteries comprises:

[0036] (1) Processing the current collector, cutting the conductive substrate foam nickel into a 1cm 2 square shape, and then sequentially ultrasonically cleaning with acetone, 3mol L -1 of hydrochloric acid, anhydrous ethanol, and deionized water for 15min, and finally drying at 60°C for 12h for standby.

[0037] (2) The active material (MXene / h-MoO3), conductive agent (acetylene black), and binder (polytetrafluoroethylene concentrate (10wt%)) were weighed in a mass ratio of 80:10:10, mixed into a uniform solid with anhydrous ethanol, coated on a clean and dry foam nickel (the coating amount of the active material is generally about 3mg), and then vacuum dried at 60°C for 12h, and then pressed into a sheet at 10MPa to obtain the working electrode.

[0038] The material prepared by the method of Example 1 was detected and electrochemically tested, and the results are shown in the accompanying drawings; and the electrochemical performance results of the following examples and comparative examples are shown in Table 1.

[0039] wherein, Figure 1 is the X-ray diffraction pattern of the MXene / h-MoO3 prepared in Example 1, and by comparison with the standard PDF card (h-MoO3), the test results show obvious h-MoO3 diffraction peaks, indicating that the MXene / h-MoO3 composite material is successfully synthesized.

[0040] Figure 2 is the scanning electron microscope pattern of the MXene / h-MoO3 prepared in Example 1, and the figure shows that MXene exhibits a rich three-dimensional layered porous structure, and irregularly aggregated h-MoO3 nanoparticles are randomly arranged and distributed on the surface and inside of MXene. MXene acts as a substrate to carry h-MoO3, and at the same time, h-MoO3 can also prevent MXene from self-stacking behavior. The electrolyte can easily diffuse in the stable MXene, thereby significantly improving the electrochemical performance.

[0041] Figure 3The cyclic voltammograms of MXene / h-MoO3 prepared in Example 1 at different scanning rates showed obvious redox peaks as the scanning rate increased, indicating good electrochemical performance.

[0042] Figure 4 The charge-discharge profiles of MXene / h-MoO3 prepared in Example 1 at different scanning current densities showed approximately symmetric characteristic shapes, indicating excellent reversibility and good coulombic efficiency of the electrode.

[0043] Figure 5 The impedance spectrogram of MXene / h-MoO3 prepared in Example 1 showed that the charge transfer resistance of the composite was very small, indicating a fast electron charge transport process.

[0044] Figure 6 The cycle performance and coulombic efficiency of the device using MXene / h-MoO3 prepared in Example 1 as electrode material in a 2 mol·L -1 Zn(OTF)2 electrolyte after 1000 cycles. The device showed excellent cycle stability with a capacity retention rate of 96.08%. The corresponding coulombic efficiency was calculated to be about 99%, indicating good reversibility of the device.

[0045] Example 2

[0046] The difference from Example 1 is only that MXene 120 mg, ammonium molybdate 80 mg, and formic acid 80 mg are mixed, and the others are the same as Example 1.

[0047] Example 3

[0048] The difference from Example 1 is only that MXene 80 mg, ammonium molybdate 120 mg, and formic acid 120 mg are mixed, and the others are the same as Example 1.

[0049] Comparative Example 1

[0050] In this comparative example, commercial polystyrene is compounded with h-MoO3, and the preparation steps are as follows:

[0051] Polystyrene 100 mg, ammonium molybdate 100 mg, and formic acid 100 mg are mixed in a mass ratio, and a uniform solution is obtained by ultrasonic stirring. The solid after centrifugation is washed with deionized water several times, and the dried polystyrene / h-MoO3 sample is obtained.

[0052] A method for preparing a finished electrode of polystyrene / h-MoO3 for a zinc ion battery, comprising:

[0053] (1) The preparation process is the same as Example 1.

[0054] (2) The active material is polystyrene / h-MoO3, and the other preparation processes are the same as in Example 1.

[0055] Comparative Example 2

[0056] In this comparative example, commercial V2O5 is compounded with h-MoO3.

[0057] V2O5100 mg, ammonium molybdate 100 mg, and formic acid 100 mg are mixed in a mass ratio, ultrasonic stirring is performed for 1 h to obtain a uniform solution, the solid after centrifugation is washed with deionized water for multiple times, and polystyrene / h-MoO3 samples are obtained after drying.

[0058] A preparation method of a V2O5 / h-MoO3 electrode for a zinc ion battery, comprising:

[0059] (1) The preparation process is the same as in Example 1.

[0060] (2) The active material is V2O5 / h-MoO3, and the other preparation processes are the same as in Example 1.

[0061] Comparative Example 3

[0062] In this comparative example, a MXene / 2D bismuth sample material is prepared, and the preparation method is as follows:

[0063] (1) The MXene material is prepared, and the preparation process is the same as in Example 1.

[0064] (2) The MXene / 2D bismuth is prepared: 0.1 mol of C 10 H 14 N2Na2O8·2H2O and 0.05 mol of Bi(NO3)3·5H2O are taken and added to 40 mL of deionized water; ultrasonic treatment is performed for 1 h, and the solid after centrifugation is washed with deionized water and ethanol for multiple times, and dried in a vacuum oven at 60°C for 6 hours. Then, 0.05 mol of MXene is dropped into the above product, 40 mL of deionized water is added, and a uniform mixed solution is obtained after ultrasonic treatment for 30 min. The solid after centrifugation is washed with deionized water for multiple times, and dried to obtain a MXene / 2D bismuth sample.

[0065] A preparation method of a finished electrode of MXene / 2D bismuth for a zinc ion battery, comprising:

[0066] (1) The preparation process is the same as in Example 1.

[0067] (2) The active material is MXene / 2D bismuth, and the other preparation processes are the same as in Example 1.

[0068] Comparative Example 4

[0069] In this comparative example, a MXene / graphene oxide is prepared, and the preparation method is as follows:

[0070] (1) Preparation of graphene oxide: 2 g of graphene raw material was placed in a 500 mL beaker, 35 mL of concentrated sulfuric acid (concentration of 98%) was added to the beaker, and stirred for 2 h; 8 g of potassium permanganate (analytical pure) was weighed, then slowly added to the above mixed solution while stirring, after the end, the beaker was placed in a 35°C constant temperature water bath for 6 h, then 100 mL of deionized water was added, and stirred for 30 min, then 20 mL of 30% hydrogen peroxide was added, stirred for 30 min, finally 30 mL of concentrated hydrochloric acid and 200 mL of deionized water were added, stirred for 30 min, and the residual substances in the solution were removed; washed with deionized water until neutral, and then the obtained precipitate was frozen and dried in a refrigerator for 24 h to obtain graphene oxide powder.

[0071] (2) Preparation of MXene / graphene oxide: the material obtained in the above step was mixed in a mass ratio of MXene 100 mg and graphene oxide 100 mg, ultrasonic stirring was carried out for 1 h to obtain a uniform solution, the solid after centrifugation was washed with deionized water for several times, and then dried to obtain a MXene / graphene oxide sample.

[0072] A method for preparing a finished electrode of MXene / graphene oxide for a supercapacitor, comprising:

[0073] (1) The preparation process is the same as that of Example 1.

[0074] (2) The active material is MXene / graphene oxide, and the other preparation processes are the same as those of Example 1.

[0075] The electrochemical performance of the above examples and comparative examples is shown in Table 1. From the results in Table 1, it can be seen that the prepared MXene / h-MoO3 (Example 1) has a higher specific capacitance and excellent electrochemical performance. This is mainly due to the addition of h-MoO3 which can provide a larger specific surface area, which can significantly improve the self-stacking of MXene and is beneficial to improve the electrochemical performance of the composite electrode material. In addition, alkali metal oxides have more energy storage active sites in the process of electrochemical energy storage, and also provide more transmission channels for electron transfer, so alkali metal oxides often have higher specific capacity than other metal oxides. The method involved in the present application has simple preparation process, low energy consumption and safer process. Since the synthesis of MXene nanosheets, this new type of two-dimensional material has become a huge demand in many research fields due to its large specific surface area, good surface chemical properties, good hydrophilicity and excellent electrical conductivity. In addition, the change of the amount of MXene added in Examples 2 and 3 affects the level of specific capacitance, but still has excellent electrochemical performance in a relatively high range.

[0076] Table 1: Electrochemical performance list of Examples 1-4

[0077] Electrode material Electrolyte Specific capacitance (F / g) Example 1 MXene / h-MoO3 2M Zn(OTF)2 395 Example 2 MXene / h-MoO3 2M Zn(OTF)2 352 Example 3 MXene / h-MoO3 2M Zn(OTF)2 329 Comparative Example 1 polystyrene / h-moo3 2M ZnSO4+ 0.1M MnSO4 280 Comparative Example 2 [V2O5 / h-MoO3] 2M Zn(OTF)2 275 Comparative Example 3 MXene / 2D bismuth 2M ZnSO4 178 Comparative Example 4 MXene / graphene oxide 3M H2SO4 220

[0078] Those skilled in the art will appreciate that various modifications and changes can be made to the present application without departing from the spirit or scope of the application. Accordingly, it is intended that all such modifications and changes be included within the scope of the application as long as they fall within the scope of the appended claims and their equivalents.

Claims

1. A method for preparing MXene / h-MoO3 electrode material for zinc ion batteries, characterized in that, It comprises the following steps: (1) Preparation of Ti3C2T x MXene material; (2) preparing MXene / h-MoO3 material: Dropping liquid MXene into a mixed solution of ammonium molybdate and formic acid, ultrasonic stirring to obtain a uniform solution, washing the solid after centrifugation with deionized water for multiple times, and drying to obtain MXene / h-MoO3.

2. The method according to claim 1, characterized in that, The mass ratio of the MXene, ammonium molybdate and formic acid is 0.5-1.5:1:1-1.

2.

3. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 1, characterized in that, Step (1) Preparation of Ti3C2T x The method of MXene material is: dissolving lithium fluoride in hydrochloric acid solution, adding titanium aluminum carbide, water bath stirring, centrifuging, washing with hydrochloric acid and then washing with deionized water, then carrying out ultrasonic ice water bath for 1h, and then carrying out centrifuging to obtain ultra-thin Ti3C2T x nanosheet.

4. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 3, characterized in that, The mass ratio of the titanium aluminum carbide, lithium fluoride and hydrochloric acid is 5:6-10:110-120; the concentration of the hydrochloric acid solution is 11-13 mol / L -1 .

5. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 3, characterized in that, The water bath stirring temperature is 40-50℃; the water bath stirring time is 46-50h; and the ultrasonic ice water bath time is 0.8-1.2h.

6. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 3, characterized in that, The centrifuge speed is 3500-4000rpm; and the solution pH after washing with deionized water is 6-7.

7. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 1, characterized in that, In the step (2), the ultrasonic stirring time is 0.8-1.2h, and the ultrasonic reaction temperature is 50-70℃.

8. The method for preparing an MXene / h-MoO3 electrode material for zinc-ion batteries according to claim 1, characterized in that, In the step (2), the centrifuge speed is 3500-4000rpm; and the drying temperature is 60-80℃.

9. A MXene / h-MoO3 electrode material, characterized in that, Prepared by the method of any one of the above claims 1-8.

10. Application of the MXene / h-MoO3 electrode material of claim 9 in a zinc ion battery.

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