Preparation method of high-performance mass-producible vanadium oxide heterostructure cathode material for aqueous zinc-ion battery

Abstract

The present invention belongs to the field of new material technologies and discloses a preparation method of a high-performance mass-producible vanadium oxide heterostructure cathode material for aqueous zinc-ion batteries. First, the present invention prepares vanadium oxide bulk materials on a large scale through low-temperature pyrolysis. The vanadium oxide bulk materials have a layered structure and are covered with flaky substances on the surface. Then, the vanadium oxide bulk materials are subjected to plasma treatment to etch away the flaky substances on the surface. At the same time, the plasma introduces defects into the shallow surface layer of the bulk materials and increases their layer spacing. Finally, the samples after plasma treatment are dispersed in a solvent and peeled into vanadium oxide heterostructure nanosheets by ultrasonic waves.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to a preparation method of a high-performance and mass-producible vanadium oxide heterostructure cathode material for aqueous zinc-ion batteries. Background Art

[0002] Traditional lithium-ion batteries have poor safety and high costs, which limit their large-scale applications. Due to the use of aqueous electrolytes and zinc anodes, aqueous zinc-ion batteries have better safety and lower costs, making them ideal devices for future stationary energy storage. However, the lack of high-performance and mass-producible cathode materials restricts the development of aqueous zinc-ion batteries. In recent years, improving the performance of electrode materials by constructing heterostructures has been widely proven to be feasible. Benefiting from unique interfacial effects and reaction mechanisms, heterostructure electrodes often have higher specific capacities, better cycling performance, and faster kinetic properties.

[0003] Despite the above advantages of heterostructures, due to the different crystal structures of different component materials, different interfacial properties and reaction mechanisms, and the influence of factors such as morphology, constructing high-performance heterostructures still faces huge challenges. In addition, existing preparation methods (such as chemical vapor deposition, atomic layer deposition, mechanical / chemical exfoliation, multi-step wet chemical reactions, etc.) have high energy consumption, long cycles, and low yields, which greatly limit the efficient preparation of heterostructure materials and their applications in aqueous zinc-ion batteries. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a preparation method of a high-performance and mass-producible vanadium oxide heterostructure cathode material for aqueous zinc-ion batteries. In the present invention, first, vanadium oxide bulk is prepared by low-temperature pyrolysis on a large scale. It has a layered structure with flaky substances covering its surface. Then, the vanadium oxide bulk is subjected to plasma treatment to etch away the flaky substances on its surface. At the same time, the plasma introduces defects in the shallow surface layer of the bulk and increases its layer spacing. Finally, the plasma-treated sample is dispersed in a solvent and exfoliated into vanadium oxide heterostructure nanosheets by ultrasonic waves.

[0005] The present invention provides a preparation method of a high-performance and mass-producible vanadium oxide heterostructure cathode material for aqueous zinc-ion batteries, which specifically includes the following steps:

[0006] (1) Ammonium metavanadate is placed in a tube furnace and pyrolyzed under an inert atmosphere to obtain vanadium oxide bulk;

[0007] (2) The vanadium oxide bulk powder obtained in step (1) is spread flat in a container, subjected to a first plasma treatment, and then the powder is taken out and shaken evenly, and then subjected to a second plasma treatment;

[0008] (3) The sample after the plasma treatment in step (2) is dispersed in a solvent and placed in an ultrasonic instrument for ultrasonic stripping. The obtained precipitate is dried to obtain a vanadium oxide heterostructure positive electrode material.

[0009] In step (1), the inert atmosphere is nitrogen, argon or argon-hydrogen mixture, the pyrolysis temperature is 200-500°C, the heating rate is 1-10°C / min, and the heating time is 1-8 hours.

[0010] In step (2), the power of the two plasma treatments is 100 to 300 watts, and the treatment time for each treatment is 10 to 60 minutes.

[0011] In step (3), the solvent is water, an organic solvent, or a mixed solution of water and an organic solvent.

[0012] In step (3), the ultrasonic power is greater than 150 watts and the ultrasonic time is not less than 0.5 hours.

[0013] In step (3), the drying condition is freeze-drying at -90 to -50°C.

[0014] The heterogeneous structure of vanadium oxide obtained by the present invention is V3O7-V6O 13 、V3O7-V2O5、V3O7-VO2、V6O 13 -V2O5、V6O 13 -VO2, VO2-V2O5, V3O7-V6O 13 -VO2, V3O7-V6O 13 -One or more of V2O5.

[0015] The vanadium oxide heterostructure positive electrode material obtained by the present invention is used for preparing aqueous zinc ion batteries.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] First, low-temperature pyrolysis can be used to prepare vanadium oxide blocks on a large scale, effectively reducing energy consumption;

[0018] Second, plasma is the core technical method of the present invention. It not only quickly etches away the flaky material on the surface of the vanadium oxide block, but also introduces defects in the shallow surface layer of the block and increases the interlayer spacing, enabling it to be ultrasonically peeled into nanosheets.

[0019] Third, the present invention can produce a variety of vanadium oxide heterostructured nanosheets with very impressive yields. The method used is simple, efficient, and pollution-free, making it fully feasible for industrial production.

[0020] Fourth, when used as the positive electrode of a zinc-ion battery, the present invention realizes the reversible transformation between vanadium oxide and zinc metavanadate based on a novel reversible transformation mechanism, and both can provide capacity. Therefore, it has a higher specific capacity and good rate performance.

[0021] Fifth, the application field of the present invention is not limited to the positive electrode material of aqueous zinc-ion batteries, and it can also be applied to other battery systems, as well as fields such as light, electricity, and catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Scanning electron microscope photograph of vanadium oxide bulk. (a) Before plasma treatment, the surface is covered with flaky substances; (b) After plasma treatment, the flaky substances on the surface disappear.

[0023] Figure 2 Scanning electron microscope photograph (a) and transmission electron microscope photograph (b) of vanadium oxide heterostructure nanosheets.

[0024] Figure 3 X-ray diffraction pattern of vanadium oxide heterostructure nanosheets.

[0025] Figure 4 Cyclic voltammogram of the battery, the scanning rate is 0.1 mV s -1 , and the voltage range is 0.2 - 1.4V. (a) Vanadium oxide heterostructure nanosheets; (b) Vanadium oxide bulk.

[0026] Figure 5 Comparison chart of rate performance of vanadium oxide heterostructure nanosheets and bulk. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0028] Example 1:

[0029] Load 0.5 g of ammonium metavanadate solid powder into a corundum crucible and place it in the middle position of a tube furnace. Evacuate the air in the furnace tube and introduce a high-purity argon-hydrogen mixed gas. Set the heating rate of the tube furnace to 1 °C per minute, the pyrolysis temperature to 400 °C, and the holding time to 1 hour. After the program ends, let the tube furnace cool naturally to room temperature and take out the sample and lay it flat in a petri dish. Place the petri dish in a plasma instrument, set the atmosphere to nitrogen, the power to 150 watts, and the treatment time to 0.5 hour. After the program ends, take out the petri dish and shake it carefully to turn the internal sample over. Put the petri dish into the plasma instrument and perform secondary treatment under the same atmosphere and program. Put the treated sample into a beaker containing 100 mL of ethanol and 100 mL of deionized water, perform ultrasonic treatment for 2 hours, collect the sample by centrifugation, and dry it in a freeze dryer for 8 hours to obtain the product V3O7-V6O 13 heterostructured nanosheets.

[0030] Figure 1 Figure 6 shows the scanning electron microscope images of the vanadium oxide bulk. (a) Before plasma treatment; (b) After plasma treatment. It can be seen from the figure that before plasma treatment, the surface of the bulk is covered with flaky substances and the interior is a layered structure; after plasma treatment, the flaky substances on the surface basically disappear.

[0031] Figure 2 Figure 10 shows the (a) scanning electron microscope image and (b) transmission electron microscope image of the vanadium oxide heterostructured nanosheets. It can be seen from the figure that after ultrasonic exfoliation, the bulk has been completely transformed into nanosheets with sizes concentrated between 100 and 300 nm. In addition, a large number of defects are formed at the edges of the nanosheets as can be seen from the inset in (b).

[0032] Figure 3 Figure 14 shows the X-ray diffraction pattern of the vanadium oxide heterostructured nanosheets. It can be seen from the figure that the product components are V3O7 and V6O 13 .

[0033] Fabricate the vanadium oxide heterostructured nanosheets and the bulk into the positive electrode of a zinc-ion battery and assemble a button battery to test its performance.

[0034] Figure 4 Figure 23 shows the cyclic voltammograms of the battery with a scanning rate of 0.1 mV s -1 , and the voltage range is 0.2 - 1.4 V. (a) Vanadium oxide heterostructured nanosheets; (b) Vanadium oxide bulk. It can be seen from the figure that a pair of redox peaks appear at 0.70 / 0.79 V for the vanadium oxide heterostructured nanosheets, corresponding to the reversible transformation between vanadium oxide and zinc pyrovanadate. However, this redox peak is not detected in the vanadium oxide bulk, indicating that this mechanism is unique to the nanosheets and is a new type of reversible transformation mechanism.

[0035] Figure 5 Comparison chart of the rate performance of vanadium oxide heterostructure nanosheets and bulk materials. The current densities are set to 0.1, 0.2, 0.5, 1.0, 2.0, 1.0, 0.5, and 0.2 A g -1 , and each current density is cycled 10 times; the voltage range is 0.2 - 1.4 V (vs Zn 2+ / Zn). It can be seen from the figure that the rate performance of the vanadium oxide heterostructure nanosheets is significantly better than that of the bulk materials. At a current density of 0.1 A g -1 , the specific capacity is higher than 400 mA h g -1 , and at a current density of 2.0 A g -1 , the specific capacity is higher than 200 mA h g -1 . The excellent electrochemical performance of the vanadium oxide heterostructure nanosheets stems from their unique and superior zinc ion storage mechanism.

[0036] Example 2:

[0037] Load 2.0 grams of ammonium metavanadate solid powder into a corundum crucible and place it in the middle position of a tube furnace. Evacuate the air in the furnace tube and introduce high-purity nitrogen. Set the heating rate of the tube furnace to 2 °C / minute, the pyrolysis temperature to 500 °C, and the holding time to 2 hours. After the program ends, let the tube furnace cool naturally to room temperature, take out the sample and spread it flat in a petri dish. Place the petri dish in a plasma instrument, set the atmosphere to nitrogen, the power to 140 watts, and the treatment time to 1 hour. After the program ends, take out the petri dish and shake it carefully to turn the internal sample over. Put the petri dish into the plasma instrument and perform secondary treatment under the same atmosphere and program. Put the treated sample into a beaker containing 200 ml of ethanol and 200 ml of deionized water, ultrasonically treat it for 1.5 hours, collect the sample by centrifugation, and dry it in a freeze dryer for 6 hours. The structure and performance of the prepared vanadium oxide heterostructure nanosheets are similar to those in Example 1, and the product obtained is V3O7-V2O5.

[0038] Example 3:

[0039] 3.0 g of ammonium metavanadate solid powder was loaded into a corundum crucible and placed at the middle position of a tubular furnace. The air in the furnace tube was evacuated, and a high-purity argon-hydrogen mixed gas was introduced. The heating rate of the tubular furnace was set at 1.5 °C / min, the pyrolysis temperature was 450 °C, and the holding time was 1.5 h. After the program ended, the tubular furnace was naturally cooled to room temperature, and the sample was taken out and laid flat in a petri dish. The petri dish was placed in a plasma instrument, the atmosphere was set as nitrogen, the power was 160 W, and the treatment time was 1 h. After the program ended, the petri dish was taken out and carefully shaken to turn the internal sample over. The petri dish was put into the plasma instrument for secondary treatment under the same atmosphere and program. The treated sample was put into a beaker containing 300 mL of ethanol and 300 mL of deionized water, ultrasonically treated for 2.5 h, the sample was collected by centrifugation, and then put into a freeze dryer for drying for 5 h. The structure and properties of the prepared vanadium oxide heterostructure nanosheets were similar to those in Example 1, and the product V3O7-VO2 was obtained.

[0040] The above embodiments are the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any obvious improvements, substitutions or modifications that those skilled in the art can make all fall within the protection scope of the present invention.

Claims

1. A preparation method of a high-performance and mass-producible vanadium oxide heterostructure cathode material for an aqueous zinc-ion battery, characterized in that, It includes the following steps: (1) Place ammonium metavanadate in a tubular furnace and pyrolyze it under an inert atmosphere to obtain a vanadium oxide bulk; In step (1), the inert atmosphere is nitrogen, argon or an argon-hydrogen mixture, the pyrolysis temperature is 200-500 °C, the heating rate is 1-10 °C / minute, and the heating time is 1-8 hours; (2) Spread the vanadium oxide bulk powder obtained in step (1) flat in a vessel, perform a first plasma treatment, then take out the powder, shake it evenly, and perform a second plasma treatment; In step (2), the power of both plasma treatments is 100-300 watts, the treatment time for each time is 10-60 minutes, and the atmosphere is nitrogen; (3) Disperse the sample after plasma treatment in step (2) in a solvent, place it in an ultrasonic instrument for ultrasonic exfoliation into nanosheets. After the obtained precipitate is dried, it is the vanadium oxide heterostructure cathode material; the obtained vanadium oxide heterostructure is V3O7-V6O 13 , V3O7-V2O5, V3O7-VO2, V6O 13 -V2O5, V6O 13 -VO2, VO2-V2O5, V3O7-V6O 13 -VO2, V3O7-V6O 13 -V2O5, or one or more of them; In step (3), the power of the ultrasonic treatment is greater than 150 watts, and the ultrasonic treatment time is not less than 0.5 hours.

2. The preparation method according to claim 1, characterized in that, In step (3), the solvent is water, an organic solvent, or a mixed solution of water and an organic solvent.

3. The preparation method according to claim 1, characterized in that, In step (3), the drying condition is freeze-drying at -90~-50 °C.

4. Vanadium oxide heterostructure cathode material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 3, and the obtained vanadium oxide heterostructure is V3O7-V6O 13 , V3O7-V2O5, V3O7-VO2, V6O 13 -V2O5, V6O 13 -VO2, VO2-V2O5, V3O7-V6O 13 -VO2, V3O7-V6O 13 -one or more of V2O5.

5. Use of the vanadium oxide heterostructure cathode material according to claim 4 for preparing an aqueous zinc-ion battery.

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