WO2019114205A1 - Mxene-metal composite material and preparation method therefor - Google Patents

Abstract

The present invention relates to an MXene-metal composite material and a preparation method therefor. The technical solution used by the present invention involves: (1) mixing metal salt particles with hydrofluoric acid to formulate a solution, further placing an MAX raw material into the solution and stirring same; and (2) after a reaction is complete, centrifuging the reaction solution in step 1), and washing and vacuum drying a solid resulting from the centrifugalization to obtain an MXene-metal composite electrode material. The present invention fully utilizes waste hydrogen gas in the process of the preparation of MXene by using MAX, and the prepared MXene-metal composite electrode material has the advantages of uniform dispersion, a high specific energy, a good circularity, a simple process, etc.; furthermore, waste gas generated during the process of reaction is effectively utilized, thereby reducing production procedures and costs, resulting in a high production efficiency, and same can better meet requirements for industrial production and realize large-scale production, so that same has great application prospects.

Description

MXene-metal composite material and preparation method thereof Technical field

The invention belongs to the technical field of lithium ion batteries, and in particular relates to an MXene-metal composite material and a preparation method thereof.

Background technique

At present, the anode material of lithium ion battery is mainly graphite electrode material, and its theoretical specific energy is only 372 mAh/g, which limits the improvement of the overall performance of lithium battery, and urgently needs to develop a new high specific energy negative electrode material system; and due to the embedded lithium battery of graphite The position is relatively low, which easily leads to decomposition of the electrolyte and precipitation of dendritic lithium, which causes a series of safety problems. Therefore, it is necessary to find a new negative electrode material which is higher in lithium insertion potential than carbon material, cheap and easy to obtain, safe and reliable. MXene is a new type of transition metal carbon (nitrogen) two-dimensional crystal with a similar structure to graphene, the chemical formula is M _n+1 X _n , where n=1, 2 or 3, M is an early transition metal element, X For carbon or nitrogen, this kind of material can be obtained by hydrofluoric acid dissociation layered ceramic material MAX (A main element), which is very suitable as a negative electrode material for lithium ion battery or sodium ion battery.

At present, the MXene material has been reported as a negative electrode material for a lithium battery. For example, the patent CN106025236A discloses a preparation method of an S-SnO ₂ /Ti ₃ C ₂ two-dimensional nano-particle ion battery anode material. S-SnO ₂ /Ti ₃ C _{2 was} prepared by using Ti ₃ AlC ₂ , SnCl ₄ ·5H ₂ O and thioacetamide as raw materials, by hydrofluoric acid etching, ultrasonic mixing, rapid stirring, water washing and drying, etc. The nanocomposite material effectively increases the capacitance, but the preparation process is complicated and the cost is high.

Patent CN106025200A discloses a preparation method of a nitrogen-doped MXene battery anode material, which adopts a nitrogen source such as Ti ₃ AlC ₂ and N ₂ as a raw material, and is made of nitrogen-doped MXene by hydrofluoric acid etching and nitrogen source heat treatment. Battery anode material. This method makes the MXene surface have a large number of defects, and the capacity is further improved. Compared with the MXene material which is not doped with nitrogen, the specific capacity can be increased by 45%; but after a plurality of cycles, the specific capacity is only about 300 mAh/g. The cycle performance has yet to be further improved.

Patent CN107161999A discloses a preparation method of a battery electrode material based on Ti ₂ C MXene, which is prepared by a process of hydrofluoric acid etching, stirring and drying, using an intercalation agent such as Ti ₃ AlC ₂ and ferric chloride. The Ti ₂ C MXene film material was obtained; however, the volume specific capacity after repeated cycles was only 290-315 mAh/g.

In addition, the metal elements Sb and Bi can also be used in lithium batteries, generally in the form of thin films or fine particles distributed in the anode material or to form intermetallic compounds or alloys into battery anode materials, because the two metal elements have potential charge and discharge characteristics. The reversible capacity is ideal, the conductivity is excellent, and the lithium insertion ability is higher than that of graphite, which is beneficial to improve the safety performance of the battery. However, when the 锑/铋 is present in the above form, the problem of pulverization or agglomeration is easily caused, which affects the performance of the lithium battery.

In summary, there are still many problems to be solved in the preparation of MXene anode materials in the prior art: (1) complicated preparation method, high cost, low efficiency, and difficult to scale production; (2) low discharge capacity and small specific capacity of the electrode The reversibility is poor after the first cycle; (3) the hydrogen exhaust gas generated during the process of preparing MXene by MAX is not utilized. Therefore, it is necessary to explore a simple process, low cost, good performance MXene material and its preparation method, and its use in the anode material of lithium ion battery is of great significance for further improvement of lithium battery performance.

Summary of the invention

In view of the above problems in the prior art, an object of the present invention is to provide an MXene-metal composite material and a preparation method thereof, and the MXene-metal composite electrode material prepared by the invention has uniform dispersion, compared with the prior art. The utility model has the advantages of high specific capacity, good cycle performance, good rate performance, simple process, high efficiency and low time consumption. Meanwhile, the invention uses hydrogen waste gas generated in the reaction process to reduce metal, and effectively utilizes hydrogen exhaust gas to reduce The production process and cost can better meet the needs of industrial production, achieve large-scale production, and have great application prospects.

One of the objects of the present invention is to provide a MXene-metal composite.

Another object of the present invention is to provide a method for preparing a MXene-metal composite.

A third object of the present invention is to provide the use of the above MXene-metal composite material and a preparation method thereof.

In order to achieve the above object, the present invention discloses the following technical solutions:

First, the present invention discloses an MXene-metal composite material composed of a MXene material and metal particles uniformly coated on the surface of the MXene material, the metal particles being a simple substance of Sb and/or Bi.

Secondly, the present invention discloses a method for preparing a MXene-metal composite material. Specifically, the preparation method comprises the following steps:

1) Mix the metal salt particles with hydrofluoric acid to form a solution, and then put the MAX powder into the solution and stir.

2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid product obtained after centrifugation is washed and vacuum dried to obtain a MXene-metal composite material.

In the step 1), the metal salt particles are one or more of a phosphonium salt and a phosphonium salt.

Preferably, the onium salt is one or more of barium chloride, barium nitrate, and barium fluoride.

Preferably, the onium salt is one or more of barium chloride and barium nitrate.

In the step 1), the MAX powder comprises: Ti ₃ AlC ₂ , Ti ₂ AlC, Ta ₄ AlC ₃ , TiNbAlC, (V _0.5 Cr _0.5 ) ₃ AlC ₂ , V ₂ AlC, Nb ₂ AlC, Nb ₄ AlC ₃ , Ti ₃ AlCN, Ti ₃ SiC ₂ , Ti ₂ SiC, Ta ₄ SiC ₃ , TiNbSiC, (V _0.5 Cr _0.5 ) ₃ SiC ₂ , V ₂ SiC, Nb ₂ SiC, Nb ₄ SiC ₃ , Ti ₃ SiCN, or the like.

Preferably, the MAX powder is Ti ₃ AlC ₂ , Ti ₂ AlC, Ti ₃ AlCN, Ti ₂ SiC.

In the step 1), the hydrofluoric acid mass fraction is 30% to 48%.

In the step 1), the mass ratio of the metal salt to the MAX is 1:1 to 1:10.

In the step 1), the reaction temperature and time are respectively 15 to 40 ° C, 10-18 h.

In step 2), the vacuum drying temperature is 80 °C.

In step 2), the vacuum drying time is 12-16 h.

In the step 2), the metal in the MXene-metal composite material is one or more of Sb and Bi.

Finally, the present invention discloses the use of MXene-metal composites prepared by the above methods, including in lithium batteries or other energy storage materials.

It should be noted that, in the present invention, the soluble salt of Sb and Bi is mixed with hydrofluoric acid, and after the metal salt is dissolved, Sb ³⁺ and Bi ^{3+ are} ionized, and then the MAX powder is added to the mixed solution, and Al in the MAX powder. The Si element reacts with hydrofluoric acid to generate hydrogen gas. At the same time as the hydrogen gas is generated, the Sb ³⁺ and Bi ³⁺ attached to the MAX surface can be reduced in situ, so that Sb and Bi form a metal element, and finally The obtained surface is covered with Sb, Bi MXene-metal composite material, and the metal element obtained by in-situ reduction can form a good bonding force with the MAX surface, and is not easy to fall off, and greatly improves the conductivity of MXene, due to Sb, Bi itself has the characteristics of accommodating a certain capacity, and can further increase the specific capacity of MXene. It can be seen that the present invention solves a plurality of technical problems by fully utilizing the hydrogen generated by the reaction of MAX powder and hydrofluoric acid, and A good technical effect has been achieved.

The MXene-metal composite described in the present invention is used as a negative electrode material for a lithium ion battery. The electrolyte of the lithium ion battery is ethylene carbonate, dimethyl carbonate, ethylene carbonate, diethyl carbonate, biphenyl (BP), vinylene carbonate (VC), ethylene carbonate (VEC), fluorine. Vinyl carbonate (FEC), 1,3-propane sultone (PS), 1,4-butane sultone (BS), 1,3-(1-propene) sultone (PST), Any one or more of vinyl sulfite (ESI), vinyl sulfate (ESA), cyclohexylbenzene (CHB), tert-butylbenzene (TBB), t-amylbenzene (TPB), and dicyandiyl (SN) A mixture of lithium salts. The lithium salt may be a mixture of one or more of the following formulas: lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), lithium bistrifluorosulfonamide (LiN(SO2CF3)2), difluorosulfonamide Lithium (LiFSI), lithium bis(oxalate)borate (LiBOB), lithium trifluoromethanesulfonate (LiSO3CF3), etc., and the concentration of the lithium salt is 0.5 to 2.5 mol/L. The positive electrode is lithium cobaltate, lithium manganate, lithium iron phosphate, lithium nickel cobalt oxide, lithium nickel cobalt manganese oxide or the like.

Compared with the prior art, the present invention achieves the following beneficial effects:

(1) The invention fully utilizes the hydrogen exhaust gas in the process of preparing MXene by MAX, and obtains a negative electrode material of lithium ion battery with excellent performance while turning waste into treasure.

(2) The MXene-metal composite prepared by the invention has the advantages of uniform dispersion, high specific energy, good cycleability and the like.

(3) The surface of the MXene prepared by the invention is coated with a metal element, which further improves the electrical conductivity of the MXene.

(4) In the present invention, the ruthenium and iridium metal coated on the surface of MXene itself have a property of accommodating a certain electric capacity, and coating it on the surface of MXene can further improve the specific energy of the MXene-metal composite prepared by the present invention.

DRAWINGS

The accompanying drawings, which are incorporated in the claims of the claims

Figure 1 is a graph showing the cycle efficiency of a sample prepared in Example 1 of the present invention.

Detailed ways

It should be noted that the following detailed description is illustrative and is intended to provide a further description of the application. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise indicated.

It is to be noted that the terminology used herein is for the purpose of describing particular embodiments, and is not intended to limit the exemplary embodiments. As used herein, the singular " " " " " " There are features, steps, operations, devices, components, and/or combinations thereof.

As described in the background art, the preparation of the existing MXene anode material also has the problems of complicated preparation method, high cost, low efficiency, poor performance, and lack of utilization of hydrogen exhaust gas. Therefore, the present invention proposes an MXene-metal composite material and The preparation method thereof will now be further described with reference to the examples.

Example 1:

1) The metal salt particles are dispersed in a hydrofluoric acid solution, and MAX is placed in the above solution and stirred.

2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.3 g of antimony trichloride.

In step 1), the MAX used is 0.5 g Ti ₃ AlC ₂ .

In step 1), the hydrofluoric acid mass fraction is 40%.

In the step 1), the reaction temperature and time are respectively: 20 ° C, 10 h.

In step 2), the vacuum drying temperature is 80 °C.

In step 2), the vacuum drying time is 14 h, that is, a Ti ₃ C ₂ -Sb composite electrode material is obtained.

Example 2:

Step 1): Disperse the metal salt particles in a hydrofluoric acid solution, and place MAX in the above solution and stir.

Step 2): After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.4 g of antimony trichloride.

In step 1), the MAX is 0.5 g Ti ₂ AlC.

In step 1), the hydrofluoric acid mass fraction is 30%.

In step 1), the reaction temperature and time are: 15 ° C, 14 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time is 12 h, that is, a Ti ₂ C-Bi composite electrode material is obtained.

Example 3:

Step 1): Disperse the metal salt particles in a hydrofluoric acid solution, and place MAX in the above solution and stir.

Step 2): After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.2 g of cesium fluoride.

In the step 1), MAX used was 0.5 g Ti ₃ AlCN.

In the step 1), the hydrofluoric acid mass fraction is 48%.

In the step 1), the reaction temperature and time were respectively: 40 ° C, 16 h.

In the step 2), the vacuum drying temperature was 80 °C.

In the step 2), the vacuum drying time is 16 h, that is, the Ti ₃ CN-Sb composite electrode material is obtained.

Example 4:

1) The metal salt particles are dispersed in a hydrofluoric acid solution, and MAX is placed in the above solution and stirred.

2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.5 g of antimony trichloride.

In step 1), the MAX used is 0.5 g Ta ₄ AlC ₃ .

In step 1), the hydrofluoric acid mass fraction is 40%.

In the step 1), the reaction temperature and time are respectively: 20 ° C, 10 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time was 14 h, that is, a Ta ₄ C ₃ -Sb composite electrode material was obtained.

Example 5:

Step 1): Disperse the metal salt particles in a hydrofluoric acid solution, and place MAX in the above solution and stir.

Step 2): After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.5 g of cerium nitrate.

In step 1), the MAX is 5 g (V _0.5 Cr _0.5 ) ₃ AlC ₂ .

In step 1), the hydrofluoric acid mass fraction is 30%.

In the step 1), the reaction temperature and time were respectively: 25 ° C, 18 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time is 12 h, that is, a (V _0.5 Cr _0.5 ) ₃ C ₂ -Bi composite electrode material is obtained.

Example 6

Step 1): Disperse the metal salt particles in a hydrofluoric acid solution, and place MAX in the above solution and stir.

Step 2): After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.5 g of cerium nitrate.

In step 1), the MAX is 5 g Ti ₃ SiCN.

In step 1), the hydrofluoric acid mass fraction is 30%.

In the step 1), the reaction temperature and time were respectively: 35 ° C, 15 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time is 12 h, that is, the Ti ₃ CN-Bi composite electrode material is obtained.

Example 7

1) The metal salt particles are dispersed in a hydrofluoric acid solution, and MAX is placed in the above solution and stirred.

2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.5 g of antimony trichloride.

In step 1), the MAX used is 0.5 g TiNbSiC.

In step 1), the hydrofluoric acid mass fraction is 40%.

In the step 1), the reaction temperature and time are respectively: 30 ° C, 10 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time is 14 h, that is, the TiNbC-Sb composite electrode material is obtained.

Example 8

1) The metal salt particles are dispersed in a hydrofluoric acid solution, and MAX is placed in the above solution and stirred.

2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid obtained after centrifugation is washed and vacuum dried to obtain an MXene-metal composite electrode material.

In the step 1), the metal salt particles are 0.5 g of antimony trichloride and 0.5 g of antimony nitrate.

In step 1), the MAX used is 1.5 g (V _0.5 Cr _0.5 ) ₃ SiC ₂ .

In step 1), the hydrofluoric acid mass fraction is 40%.

In the step 1), the reaction temperature and time were respectively: 35 ° C, 17 h.

In step 2), the vacuum drying temperature is 80 °C.

In the step 2), the vacuum drying time is 14 h, that is, a Bi-(V _0.5 Cr _0.5 ) ₃ C ₂ -Sb composite electrode material is obtained.

Performance Testing:

The Ti ₃ C ₂ -Sb composite electrode material obtained in Example 1 was made into a negative electrode of a lithium ion battery, and the above negative electrode was subjected to charge and discharge test at a rate of 0.5 C. The result is shown in FIG. It can be seen that the specific discharge capacity of the first week reaches 711 mAh/g. After 22 weeks of cycle, the specific discharge capacity can still reach 497 mAh/g, compared with the electrochemical performance of the MXene anode material in the background section, regardless of the discharge specific capacity. It is also cyclical, which has been greatly improved. This shows that the use of hydrogen gas in the surface of MXene coated with metal element makes the electrochemical performance of MXene effectively improved.

The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and various changes and modifications may be made to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application are intended to be included within the scope of the present application.

Claims (10)

1. An MXene-metal composite material characterized in that the MXene-metal composite material is composed of an MXene material and metal particles uniformly coated on the surface of the MXene material, and the metal particles are simple substances of Sb and/or Bi.
2. A method of preparing a MXene-metal composite according to claim 1, wherein the preparation method comprises the following steps:

   1) mixing the metal salt particles with hydrofluoric acid to form a solution, and then adding the MAX powder to the solution for stirring;

   2) After the reaction is completed, the reaction liquid in the step 1) is centrifuged, and the solid product obtained after centrifugation is washed and vacuum dried to obtain a MXene-metal composite material.
3. The method for preparing a MXene-metal composite according to claim 2, wherein in the step 1), the metal salt particles are one or more of a cerium salt and a cerium salt;

   Preferably, the onium salt is one or more of barium chloride, barium nitrate, and barium fluoride;

   Preferably, the onium salt is one or more of barium chloride and barium nitrate.
4. The method for preparing a MXene-metal composite according to claim 2 or 3, wherein in the step 1), the MAX powder comprises: Ti ₃ AlC ₂ , Ti ₂ AlC, Ta ₄ AlC ₃ , TiNbAlC, ( V _0.5 Cr _0.5 ) ₃ AlC ₂ , V ₂ AlC, Nb ₂ AlC, Nb ₄ AlC ₃ , Ti ₃ AlCN, Ti ₃ SiC ₂ , Ti ₂ SiC, Ta ₄ SiC ₃ , TiNbSiC, (V _0.5 Cr _0.5 ) ₃ SiC ₂ , V ₂ SiC, Nb ₂ SiC, Nb ₄ SiC ₃ /Ti ₃ SiCN, etc.; preferably, the MAX powder is Ti ₃ AlC ₂ , Ti ₂ AlC, Ti ₃ AlCN, Ti ₂ SiC.
5. The method for preparing a MXene-metal composite according to claim 4, wherein in the step 1), the mass ratio of the metal salt to the MAX is 1:1 to 1:10.
6. The method for preparing a MXene-metal composite according to claim 4, wherein in the step 1), the hydrofluoric acid mass fraction is 30% to 48%.
7. The method for preparing a MXene-metal composite according to claim 5, wherein in the step 1), the reaction temperature and time are respectively 15 to 40 ° C, 10 to 18 h.
8. The method for preparing a MXene-metal composite according to claim 7, wherein in the step 2), the vacuum drying temperature is 80 ° C; and the vacuum drying time is 12-16 h.
9. The method for preparing a MXene-metal composite according to claim 8, wherein in the step 2), the metal in the MXene-metal composite material is one or more of Sb and Bi.
10. The use of the MXene-metal composite according to claim 1 and/or the preparation method of the MXene-metal composite according to any one of claims 2-3 in a lithium battery or other energy storage material.

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