An electrode material with excellent expansion resistance and its preparation method and application

Abstract

The present invention discloses an electrode material with excellent anti-swelling performance, its preparation method and application, and the present invention belongs to the field of energy storage technology. The electrode material is an H2V3O8 / MXene / VO2 heterojunction material, and the lattice change rules of the two materials H2V3O8 and VO2 are opposite during the charge and discharge process. The present invention successfully synthesizes the H2V3O8 / MXene / VO2 heterojunction material through a one-step high-temperature mixed hydrothermal method, and the H2V3O8 / MXene / VO2 heterojunction material can slow down the volume expansion during the charge and discharge process. At the same time, the successful construction of the heterojunction material enables the redistribution of charges at the interface, and the formation of the built-in electric field accelerates the ion diffusion kinetics and induces more active sites. This material has a high reversible specific capacity, excellent rate performance, good cycle stability and anti-swelling performance when used as a cathode material for zinc-ion batteries.

Description

Technical Field

[0001] The present invention relates to an electrode material and a preparation method and application thereof, and in particular to an electrode material with excellent expansion resistance and a preparation method and application thereof. Background Art

[0002] In recent years, the massive consumption of traditional fossil fuels has increasingly aggravated environmental pollution. Therefore, the demand for clean energy is increasing, and there is an urgent need to develop safe and environmentally friendly electrochemical energy storage systems. Aqueous zinc-ion batteries (ZIBs) have low redox potential and high theoretical specific capacity (820 mAh g -1 ), low cost (low price of Zn) and easy assembly have attracted much attention. In addition, the aqueous electrolyte used in zinc-ion batteries is non-toxic and very environmentally friendly. However, the slow kinetics of zinc ions has always hindered its further development. Therefore, the development of positive electrode materials with high specific capacity and long cycle life is a top priority for zinc-ion batteries. To date, manganese-based oxides, Prussian blue, transition metal sulfides and vanadium oxides have been widely used as positive electrode materials for zinc-ion batteries. Among them, vanadium oxide materials have good adaptability in battery systems due to their advantages such as multiple redox states, open crystal structure and high theoretical specific capacity. However, their poor ion diffusion, slow kinetics and Zn 2+ The multiple insertion / extraction in the lattice induces the structural destruction of vanadium oxides, which greatly limits their further application in ZIBs. Therefore, it is very important to modify the vanadium oxide materials to improve their structural stability and cycle performance so that they meet the practical application conditions of ZIBs. Summary of the invention

[0003] Purpose of the invention: The first purpose of the present invention is to provide an electrode material with excellent expansion resistance; the second purpose of the present invention is to provide a one-step high-temperature mixed hydrothermal method for preparing the above-mentioned electrode material; the third purpose of the present invention is to provide the application of the above-mentioned electrode material as a positive electrode material in a zinc ion battery.

[0004] Technical solution: The electrode material with excellent expansion resistance described in the present invention is a H2V3O8 / MXene / VO2 heterojunction material. During the charge and discharge process, the lattice change rules of H2V3O8 / MXene and VO2 / MXene are opposite (during the discharge process, the volume of H2V3O8 / MXene shrinks, and the volume of VO2 / MXene expands; during the charge process, the volume of H2V3O8 / MXene expands, and the volume of VO2 / MXene shrinks), which fully alleviates the volume expansion of the heterojunction material during the charge and discharge process, so that it has excellent expansion resistance. The formation of the built-in electric field of the heterojunction accelerates the ion diffusion dynamics and induces more active sites.

[0005] Furthermore, nanorod-shaped H2V3O8 / MXene and VO2 / MXene are evenly distributed on the surface of MXene nanosheets to form H2V3O8 / MXene / VO2 heterojunction materials.

[0006] The method for preparing the electrode material with excellent expansion resistance of the present invention comprises the following steps:

[0007] (1) preparing H2V3O8 / MXene aqueous solution as liquid A and VO2 / MXene aqueous solution as liquid B;

[0008] (2) placing liquid A and liquid B in a hydrothermal reactor with different reaction chambers and heating them;

[0009] (3) When the temperature reaches the reaction temperature, the hydrothermal reactor is rotated to mix liquid A and liquid B. During the reaction, the reactor is always in a rotating state, and the target material is prepared after the reaction.

[0010] Furthermore, in step (1), the concentration of the H2V3O8 / MXene aqueous solution is 0.01 to 0.05 g / mL.

[0011] Furthermore, in step (2), the concentration of the VO2 / MXene aqueous solution is 0.01 to 0.05 g / mL.

[0012] Furthermore, in step (3), the rotation speed is controlled at 10-15 rpm, and the hydrothermal reaction temperature is 180-240°C.

[0013] Furthermore, after the reaction is completed, the reactor is continuously stirred and cooled to room temperature, and a black powder electrode material is obtained after filtration, washing and drying.

[0014] The present invention further protects the application of the electrode material as a positive electrode material in a zinc ion battery.

[0015] The preparation principle of the present invention is: using H2V3O8 / MXene and VO2 / MXene as raw materials, using water as solvent, and synthesizing a H2V3O8 / MXene / VO2 composite material with a heterogeneous structure through a one-step high-temperature mixed hydrothermal method. The high-temperature mixed hydrothermal method can effectively improve the crystallinity and purity of the product and avoid the generation of other impurities during the heating process. Through high-temperature rotary mixing technology, H2V3O8 / MXene and VO2 / MXene can be effectively compounded to form a heterogeneous structure. The successful construction of the heterojunction material enables the charge to be redistributed at the interface, and the formation of the built-in electric field accelerates the ion diffusion dynamics and induces more active sites. At the same time, the volume changes of the two raw materials H2V3O8 / MXene and VO2 / MXene during the charge and discharge process are opposite. Combining the two can fully alleviate the overall volume expansion of the positive electrode, so that it has excellent expansion resistance.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The electrode material has excellent expansion resistance. The present invention constructs a heterostructure of two materials with opposite volume changes during charging and discharging, which fully alleviates the volume expansion during charging and discharging, and makes it have excellent expansion resistance. At the same time, the formation of the built-in electric field of the heterojunction accelerates the ion diffusion dynamics and induces more active sites, effectively improving the conductivity and specific capacity of the electrode material; (2) The one-step high-temperature mixed hydrothermal method is used to synthesize the H2V3O8 / MXene / VO2 zinc ion battery positive electrode material, which not only simplifies the experimental process and reduces the experimental cost, but also improves the conductivity and structural stability of the material, alleviates the problem of volume expansion during charging and discharging, and provides an excellent positive electrode material for the application of aqueous zinc ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The preparation flow chart of H2V3O8 / MXene / VO2 electrode materials with heterostructure;

[0018] Figure 2 This is a SEM image of the H2V3O8 / MXene / VO2 electrode material prepared in Example 1;

[0019] Figure 3 TEM image of the H2V3O8 / MXene / VO2 electrode material prepared in Example 1;

[0020] Figure 4 The H2V3O8 / MXene / VO2 electrode in Example 1 and the positive electrode materials in Examples 2 and 3 are 0.1Ag -1 Cyclic performance diagram at current density of ;

[0021] Figure 5The H2V3O8 / MXene / VO2 electrode in Example 1 and the positive electrode materials in Examples 4 and 5 are 0.1Ag -1 Cyclic performance diagram at current density of ;

[0022] Figure 6 The H2V3O8 / MXene / VO2 electrode in Example 1 and the positive electrode materials in Comparative Examples 1 and 2 are 0.1Ag -1 Cyclic performance diagram at current density of ;

[0023] Figure 7 XRD diagram of the H2V3O8 / MXene / VO2 electrode prepared in Example 1 at different charge and discharge stages;

[0024] Figure 8 Schematic diagram of compounding two materials with opposite volume changes during the charge and discharge process. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] Example 1

[0027] A method for preparing a positive electrode material for a zinc ion battery with excellent expansion resistance, the preparation process is as follows Figure 1 As shown, the specific steps are as follows:

[0028] Step 1) Add 0.1 g H2V3O8 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution A (the preparation method of H2V3O8 / MXene is the same as that of Comparative Example 1, reference: Penghua Liang, Tengfei Xu, Kongjun Zhu, *etal. Heterogeneous interface-boosted zinc storage of H2V3O8 nanowire / Ti3C2T x MXene composite towards high-rate and long cycle lifespan aqueous zinc-ionbatteries, Energy Storage Materials, 2022, 50, 63-74.);

[0029] Step 2) Add 0.1 g VO2 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to prepare solution B (the preparation method of VO2 / MXene is the same as that of Comparative Example 2, see Penghua Liang, Kongjun Zhu*, Jiatao Chen et al. Oxygen vacancies and heterointerface co-boosted Zn 2+ (De)intercalationkinetics in VO2 for ultra-efficient aqueous zinc-ion batteries, Journal of Power Sources, 2023, 568, 232945.);

[0030] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml); seal the hydrothermal reactor and place it in an oven for heating. During the heating process, ensure that liquid A and liquid B do not come into contact before reaching the reaction temperature;

[0031] Step 4) When the reaction temperature in step 3) rises to 200°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and the reaction is carried out at 200°C for 1 hour.

[0032] Step 5) The reactor is continuously stirred and cooled to room temperature, and black powder of H2V3O8 / MXene / VO2 heterojunction material is obtained after filtration, washing and drying.

[0033] See also Figure 2 It can be seen that the morphology of the prepared H2V3O8 / MXene / VO2 electrode is a composite structure of H2V3O8, VO2 nanorods and MXene nanosheets. Figure 3 , the composite of MXene nanosheets and nanorods of different thicknesses can be seen more clearly.

[0034] Example 2

[0035] Step 1) Add 0.2 g H2V3O8 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution A;

[0036] Step 2) Add 0.1 g VO2 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution B;

[0037] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml); seal the hydrothermal reactor and place it in an oven for heating. During the heating process, ensure that liquid A and liquid B do not come into contact before reaching the reaction temperature;

[0038] Step 4) When the reaction temperature in step 3) rises to 200°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and the reaction is carried out at 200°C for 1 hour.

[0039] Step 5) The reactor is continuously stirred and cooled to room temperature, and black powder of H2V3O8 / MXene / VO2 heterojunction material is obtained after filtration, washing and drying.

[0040] Example 3

[0041] Step 1) Add 0.1 g H2V3O8 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution A;

[0042] Step 2) Add 0.2 g VO2 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution B;

[0043] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml); seal the hydrothermal reactor and place it in an oven for heating. During the heating process, ensure that liquid A and liquid B do not come into contact before reaching the reaction temperature;

[0044] Step 4) When the reaction temperature in step 3) rises to 200°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and the reaction is carried out at 200°C for 1 hour.

[0045] Step 5) The reactor is continuously stirred and cooled to room temperature, and black powder of H2V3O8 / MXene / VO2 heterojunction material is obtained after filtration, washing and drying.

[0046] Example 4

[0047] Step 1) Add 0.1 g H2V3O8 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution A;

[0048] Step 2) Add 0.1 g VO2 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution B;

[0049] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml); seal the hydrothermal reactor and place it in an oven for heating. During the heating process, ensure that liquid A and liquid B do not come into contact before reaching the reaction temperature;

[0050] Step 4) When the reaction temperature in step 3) rises to 180°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and reacted at 180°C for 1 hour.

[0051] Step 5) The reactor is continuously stirred and cooled to room temperature, and black powder of H2V3O8 / MXene / VO2 heterojunction material is obtained after filtration, washing and drying.

[0052] Example 5

[0053] Step 1) Add 0.1 g H2V3O8 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution A;

[0054] Step 2) Add 0.1 g VO2 / MXene to 10 mL aqueous solution and ultrasonically treat for 10 min to obtain solution B;

[0055] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml); seal the hydrothermal reactor and place it in an oven for heating. During the heating process, ensure that liquid A and liquid B do not come into contact before reaching the reaction temperature;

[0056] Step 4) When the reaction temperature in step 3) rises to 220°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and the reaction is carried out at 220°C for 1 hour.

[0057] Step 5) The reactor is continuously stirred and cooled to room temperature, and black powder of H2V3O8 / MXene / VO2 heterojunction material is obtained after filtration, washing and drying.

[0058] Comparative Example 1

[0059] Step 1) Prepare 12 mL of 2.4 mol L -1 The V2O5 aqueous solution is used as liquid A;

[0060] Step 2) Prepare 12 mL of 0.01 mol L -1 Glucose solution was used as liquid B, and 0.01 g MXene (0.83 g L -1 ) was added to solution B and ultrasonicated for 1 h;

[0061] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml), seal the hydrothermal reactor and heat it in an oven. During the heating process, ensure that liquid A and liquid B do not come into contact before the reaction temperature is reached;

[0062] Step 4) When the reaction temperature in step 3) rises to 240°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and reacted at 240°C for 1 hour.

[0063] Step 5) The reactor is continuously stirred and cooled to room temperature, and H2V3O8 / MXene black powder is obtained after filtration, washing and drying.

[0064] Comparative Example 2

[0065] Step 1) Prepare 12 mL of 2.4 mol L -1 The V2O5 aqueous solution is used as liquid A;

[0066] Step 2) Prepare 12 mL of 0.01 mol L -1 Glucose solution was used as liquid B, and 0.03 g MXene (1.25 g L -1 ) was added to solution B and ultrasonicated for 1 h;

[0067] Step 3) Place liquid A and liquid B in a hydrothermal reactor with different reaction chambers (total volume 60 ml), seal the hydrothermal reactor and heat it in an oven. During the heating process, ensure that liquid A and liquid B do not come into contact before the reaction temperature is reached;

[0068] Step 4) When the reaction temperature in step 3) rises to 240°C, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is kept rotating and reacted at 240°C for 1 hour.

[0069] Step 5) The reactor is continuously stirred and cooled to room temperature, and VO2 / MXene black powder is obtained after filtration, washing and drying.

[0070] Table 1 Test results

[0071]

[0072]

[0073] It can be seen from Table 1 that when the addition amount of H2V3O8 / MXene is 0.1g, the addition amount of VO2 / MXene is 0.1g, and the hydrothermal reaction temperature is 200℃, the material -1 The specific capacity at a current density of 457 mAh g -1 .

[0074] Among them, the H2V3O8 / MXene / VO2 electrodes prepared in Examples 1-5, the H2V3O8 / MXene electrodes prepared in Comparative Example 1, and the VO2 / MXene electrodes prepared in Comparative Example 2 were 0.1Ag -1 The cycling performance diagram at the current density is shown in Figure 4-6 As shown. Figure 6 As shown, the H2V3O8 / MXene / VO2 heterojunction electrode (457 mAh g -1 ) has a significantly higher cycling performance than the single H2V3O8 / MXene electrode (381 mAh g -1 ) and VO2 / MXene electrode (312mAh g-1 ). The interaction between the multiphases of heterojunction materials enhances the structural stability. At the same time, the successful construction of the heterojunction enables the redistribution of charges at the interface, and the formation of a built-in electric field accelerates the ion diffusion dynamics and induces more active sites.

[0075] Depend on Figure 7 It can be seen that the peak of the (200) crystal plane at 10.6° represents H2V3O8 / MXene. During the discharge process, the peak shifted to the right, the lattice shrank, the volume decreased, and gradually recovered during the charging process; while the peak of the (110) crystal plane at 25.3° represents VO2 / MXene. During the discharge process, the peak shifted to the left, the lattice expanded, the volume increased, and gradually recovered during charging. The schematic diagram is shown in Figure 8 As shown. It can be found that the volume changes of the two materials are opposite in different charge and discharge stages. Therefore, after the two are combined, the volume expansion of the electrode material during charge and discharge is greatly alleviated, and the expansion resistance of the material is effectively improved. Therefore, when used in the positive electrode of zinc ion batteries, it exhibits excellent electrochemical performance.

Claims

1. An electrode material having excellent expansion resistance, characterized in that: It is a H2V3O8 / MXene / VO2 heterojunction material. During the discharge process, the volume of H2V3O8 / MXene shrinks and the volume of VO2 / MXene expands; during the charging process, the volume of H2V3O8 / MXene expands and the volume of VO2 / MXene shrinks; nanorod-shaped H2V3O8 / MXene and VO2 / MXene are evenly distributed on the surface of MXene nanosheets, forming a H2V3O8 / MXene / VO2 heterojunction material.

2. A method for preparing the electrode material with excellent expansion resistance according to claim 1, characterized in that: The following steps are involved: (1) Prepare H2V3O8 / MXene aqueous solution as liquid A and VO2 / MXene aqueous solution as liquid B; (2) placing liquid A and liquid B in hydrothermal reactors with different reaction chambers and heating them; (3) When the temperature reaches the reaction temperature, the hydrothermal reactor is rotated to mix liquid A and liquid B. The reactor is always in a rotating state during the reaction, and the target material is prepared after the reaction.

3. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: During the heating process, ensure that liquid A and liquid B do not come into contact, and mix the samples when the temperature rises to the reaction temperature.

4. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: In step (1), the concentration of the H2V3O8 / MXene aqueous solution is 0.01~0.05 g / mL.

5. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: In step (2), the concentration of the VO2 / MXene aqueous solution is 0.01~0.05 g / mL.

6. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: In step (3), the reaction temperature is 180-240°C and the reaction time is 1-3 h.

7. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: In step (3), the rotation speed is controlled at 10-15 rpm.

8. The method for preparing an electrode material having excellent expansion resistance according to claim 2, characterized in that: After the reaction is completed, the reactor is continuously stirred and cooled to room temperature, and a black powder electrode material is obtained after filtration, washing and drying.

9. Use of the electrode material with excellent expansion resistance according to claim 1 as a positive electrode material in a zinc ion battery.

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