Vanadium oxide-based composite material, preparation method and application thereof, and lithium ion battery

Abstract

The application discloses a vanadium oxide-based composite material, a preparation method and application thereof, and a lithium ion battery, and belongs to the field of electrode materials. The average particle size of the vanadium oxide-based composite material is any value in a range from 1 to 50 mu m, the tap density is any value in a range from 0.8 to 2 g / cm 3 , and the specific surface area is not more than 50 m 2 / g. The application is applied to the lithium ion battery field, and solves the technical problem that the bulk ion transmission process of the existing large-size and high-density micron electrode material is slow, and this problem is particularly obvious at low temperature. The vanadium oxide-based composite material not only has high tap density, but also can realize the double fast transmission of ions and electrons in the bulk phase of the material, and has high rate performance and long cycle stability even at extremely low temperature (lower than -40 DEG C).

Description

Technical Field

[0001] This invention belongs to the field of electrode materials, and particularly relates to a vanadium oxide-based composite material, its preparation method, application and lithium-ion battery. Background Technology

[0002] With the increasing application of lithium-ion batteries in high-altitude, high-latitude, deep-space, and deep-sea environments, the performance requirements for lithium-ion batteries in extreme low-temperature environments are becoming increasingly stringent. However, the lithium-ion transport kinetics in lithium battery electrode materials deteriorate significantly at low temperatures, leading to severe polarization of the electrode materials and a sharp decline in lithium storage performance. This is a bottleneck problem restricting substantial breakthroughs in low-temperature lithium-ion batteries.

[0003] Most existing technologies employ a nanoscale strategy, controlling the particle size of electrode materials to a few hundred nanometers to shorten the transport distance of lithium ions in the electrode bulk phase, thereby promoting rapid electrochemical reactions. However, nanoelectrode materials have low packing density, large specific surface area, and severe surface side reactions. They also often require large amounts of conductive agents, binders, and electrolytes, resulting in low overall energy density and poor stability of the battery, making it difficult to meet practical application requirements. In contrast, large-size micron-scale electrode materials are advantageous for achieving high quality and volumetric energy density, meeting the miniaturization needs of future devices and thus possessing greater practical significance.

[0004] However, the bulk ion transport process of large-size, high-density micron electrode materials is slow, especially at low temperatures. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention solves the technical problem of slow bulk ion transport in existing large-size, high-density micron electrode materials, especially at low temperatures. It proposes a vanadium oxide-based composite material that not only has high tap density but also enables rapid dual transport of ions and electrons within the bulk phase, and maintains high rate performance and long cycle stability even at extremely low temperatures (below -40°C). The invention also describes its preparation method, applications, and lithium-ion batteries.

[0006] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a vanadium oxide-based composite material, wherein the average particle size of the vanadium oxide-based composite material is any value between 1 and 50 μm, and the tap density is 0.8-2 g / cm³. 3 For any value in the range, the specific surface area does not exceed 50m². 2 / g.

[0008] Preferably, the vanadium oxide-based composite material is a hybrid interlocking structure of vanadium oxide and carbon nanotubes, wherein the vanadium oxide and the carbon nanotubes are bonded by chemical bonds.

[0009] Preferably, the vanadium oxide-based composite material is based on vanadium oxide, with carbon nanotubes dispersed in the bulk phase of the vanadium oxide as a supporting framework, and the carbon nanotubes serving as electron channels at the grain boundaries of the vanadium oxide.

[0010] Preferably, the mass fraction of carbon nanotubes in the vanadium oxide-based composite material is any value between 0% and 10%.

[0011] Preferably, the vanadium oxide is selected from at least one of vanadium dioxide, vanadium pentoxide, vanadium trioxide, vanadium monoxide, and vanadium tridecyloxide; the diameter of the carbon nanotube is any value between 10-100 nm, and is selected from single-walled carbon nanotubes or multi-walled carbon nanotubes.

[0012] The present invention also provides a method for preparing vanadium oxide-based composite materials according to any of the above technical solutions, including a precursor preparation step and a calcination step;

[0013] The precursor preparation steps include: acidifying carbon nanotubes, dispersing them, adding vanadium-based raw materials and catalysts, and stirring thoroughly at 20-120°C to obtain a precursor solution;

[0014] The calcination step includes calcining the precursor solution after solvent removal at a temperature of 200-600℃.

[0015] Preferably, the vanadium-based raw material is selected from at least one of amine metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium acetylacetonate, vanadium oxalate, vanadium pentoxide, vanadium dioxide, and vanadium trioxide; the catalyst is selected from at least one of oxalic acid, sulfuric acid, phosphoric acid, hydrochloric acid, and acetic acid; and the mass ratio of the vanadium-based raw material to the carbon nanotubes is 0.1:1-100:1.

[0016] Preferably, the method for solvent removal and drying of the precursor includes freeze drying, stirred evaporation drying, rotary evaporation, and static natural drying; the calcination atmosphere of the calcination step is air, nitrogen, argon, argon-hydrogen mixture, or vacuum.

[0017] In another aspect, the present invention provides the application of the vanadium oxide-based composite material described in any of the above technical solutions in electrode materials.

[0018] The present invention also provides a lithium-ion battery, wherein the electrode material of the lithium-ion battery comprises the vanadium oxide-based composite material described in any of the above technical solutions.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention provides a vanadium oxide-based composite material. This vanadium oxide-based composite electrode material has a large size and a structure featuring a hybrid inlay of vanadium oxide and carbon nanotube networks. It has dual fast ion-electron transport channels and can integrate the advantages of high tap density, low specific surface area, and fast ion transport to achieve excellent lithium storage performance at low temperatures, especially in extremely low temperature environments (below -40°C).

[0021] This invention provides a method for preparing vanadium oxide-based composite materials. In the precursor preparation step, carbon nanotubes are first acidified to improve their dispersibility. By limiting the treatment temperature, a chemical reaction occurs between the raw materials, and the adsorption of vanadium oxide precursor molecules is improved through chemical bonding. This method has the advantages of simple process and low preparation cost.

[0022] This invention provides a lithium-ion battery that uses vanadium oxide-based composite material as the electrode material and can be used in extreme environments such as extreme cold and high altitude. Attached Figure Description

[0023] Figure 1 This is a SEM image of the vanadium oxide-based composite material provided in Example 1 of the present invention;

[0024] Figure 2 This is a partially enlarged SEM image of the vanadium oxide-based composite material provided in Example 1 of the present invention;

[0025] Figure 3 The rate performance diagrams of the vanadium oxide-based composite material provided in Example 1 of this invention at room temperature and low temperature are shown.

[0026] Figure 4 This is a graph showing the high-current cycling performance of the vanadium oxide-based composite material provided in Example 1 of the present invention at low temperatures;

[0027] Figure 5 This is a SEM image of the vanadium oxide-based composite material provided in Comparative Example 1 of the present invention;

[0028] Figure 6 This is a partially enlarged SEM image of the vanadium oxide-based composite material provided in Comparative Example 1 of the present invention.

[0029] Figure 7 This is a rate performance diagram of the vanadium oxide-based composite material provided in Comparative Example 1 of the present invention at room temperature and low temperature.

[0030] Figure 8 This is a SEM image of the vanadium oxide-based composite material provided in Comparative Example 2 of the present invention;

[0031] Figure 9This is a partially enlarged SEM image of the vanadium oxide-based composite material provided in Comparative Example 2 of the present invention;

[0032] Figure 10 The graph shows the rate performance of the vanadium oxide-based composite material provided in Comparative Example 2 of this invention at room temperature and low temperature. Detailed Implementation

[0033] The technical solutions in specific embodiments of the present invention will now be described in detail and completely with reference to the accompanying drawings. Obviously, the described embodiments are merely some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0034] This invention provides a vanadium oxide-based composite material, wherein the average particle size of the vanadium oxide-based composite material is any value between 1 and 50 μm, and the tap density is 0.8-2 g / cm³. 3 For any value in the range, the specific surface area does not exceed 50m². 2 / g. This vanadium oxide-based composite electrode material possesses large size, high tap density, and low specific surface area, ensuring excellent lithium storage performance at low temperatures, especially in extremely low-temperature environments (below -40℃). It is understood that the average particle size of the vanadium oxide-based composite material can also be any value within the range of 5, 10, 15, 20, 25, 30, 35, 40, 45 μm; the tap density can also be 1.0, 1.2, 1.4, 1.6, 1.8 g / cm³. 3 and any point value within its range.

[0035] In a preferred embodiment, the vanadium oxide-based composite material is a hybrid embedded structure of vanadium oxide and carbon nanotubes, with the vanadium oxide and carbon nanotubes bonded by chemical bonds. The vanadium oxide and carbon nanotubes in this composite material are chemically bonded and interwoven, forming a structure similar to reinforced concrete. The vanadium oxide-based composite material is predominantly vanadium oxide, with carbon nanotubes acting as a supporting framework dispersed within the bulk phase of the vanadium oxide. The carbon nanotubes serve as electron channels at the grain boundaries of the vanadium oxide. This vanadium oxide-based composite electrode material features a large-size structure with a hybrid embedded network of vanadium oxide and carbon nanotubes, providing dual rapid ion-electron transport channels. It integrates high tap density, low specific surface area, and rapid ion transport advantages, achieving excellent lithium storage performance at low temperatures, especially in extremely low-temperature environments (below -40°C), making it suitable for applications in extreme environments such as frigid and high-altitude conditions.

[0036] In a preferred embodiment, the mass fraction of carbon nanotubes in the vanadium oxide-based composite material is any value between 0% and 10%. This technical solution specifically limits the mass fraction of carbon nanotubes in the vanadium oxide-based composite material because carbon nanotubes play a role in electronic conductivity in the composite material but do not possess lithium storage activity; too high a content would affect the overall capacity and energy density of the composite material. It is understood that this mass fraction can also be any value within the range of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%.

[0037] In a preferred embodiment, the vanadium oxide is selected from at least one of vanadium dioxide, vanadium pentoxide, vanadium trioxide, vanadium monoxide, and vanadium tridecyloxide; the diameter of the carbon nanotube is any value between 10-100 nm, and is selected from single-walled carbon nanotubes or multi-walled carbon nanotubes.

[0038] The present invention also provides a method for preparing vanadium oxide-based composite materials according to any of the above technical solutions, including a precursor preparation step and a calcination step;

[0039] The precursor preparation steps include: acidifying and dispersing carbon nanotubes, adding vanadium-based raw materials and catalysts, and stirring thoroughly at 20-120℃ to obtain a precursor solution, namely, a vanadium oxide-based composite sol. Specifically, this involves: ultrasonically dispersing the acidified carbon nanotubes, then adding vanadium-based raw materials and catalysts, and stirring thoroughly at 20-120℃ for 0.5-12 hours to ensure uniform mixing. This step uses a redox reaction to prepare the vanadium oxide-based composite sol. Acidification of the carbon nanotubes improves their dispersibility, and the hydroxyl and carboxyl functional groups modified on the surface of the carbon nanotubes facilitate the adsorption of vanadium oxide precursor molecules.

[0040] The calcination step includes calcining the precursor solution after solvent removal at a temperature of 200-600℃. Optionally, the heating rate is 1-10℃ / min, and the calcination time is 1-12h.

[0041] It should be noted that the above preparation method also includes a precursor freeze-drying step, specifically: freeze-drying the precursor solution to remove the solvent for 24-72 hours. It should be noted that the freeze-drying method used in this invention not only removes the solvent, but also, due to the synergistic effect of freeze-drying and the support of the carbon nanotube framework, induces the formation of large-size vanadium oxide-based composite materials, resulting in materials with high tap density and high energy density. In this preparation method, the conductive carbon network combined with the microporous ion transport channels generated by pyrolysis simultaneously achieves good electronic conductivity and rapid ion transport at low temperatures. The material synthesis operation is simple, time-saving, and energy-efficient, enabling low-cost mass production.

[0042] In a preferred embodiment, the vanadium-based raw material is selected from at least one of amine metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium acetylacetonate, vanadium oxalate, vanadium pentoxide, vanadium dioxide, and vanadium trioxide; the catalyst is selected from at least one of oxalic acid, sulfuric acid, phosphoric acid, hydrochloric acid, and acetic acid; and the mass ratio of the vanadium-based raw material to the carbon nanotubes is 0.1:1-100:1.

[0043] In a preferred embodiment, the calcination atmosphere during the calcination step is air, nitrogen, argon, an argon-hydrogen mixture, or vacuum. Optionally, the background gas flow rate is 10-50 mL / min or the vacuum degree is 10. -7 -10 -5 Pa.

[0044] In another aspect, this invention provides the application of the vanadium oxide-based composite material described in any of the above-mentioned technical solutions in electrode materials. This vanadium oxide-based composite material features large size, high tap density, and low specific surface area, ensuring excellent lithium storage performance at low temperatures, especially in extremely low temperature environments (below -40°C), when used as an electrode material.

[0045] This invention also provides a lithium-ion battery, wherein the electrode material of the lithium-ion battery comprises the vanadium oxide-based composite material described in any of the above-mentioned technical solutions. This lithium-ion battery can be used in extreme environments such as frigid conditions and high altitudes, and can still achieve efficient and stable lithium-ion storage even in extreme environments.

[0046] To provide a clearer and more detailed description of the vanadium oxide-based composite material, its preparation method, applications, and lithium-ion batteries provided in the embodiments of the present invention, specific embodiments will be described below.

[0047] Example 1

[0048] Precursor preparation: Weigh 200 mg of carbon nanotubes and ultrasonically disperse them in 10 ml of deionized water. Add 30 mmol of oxalic acid and stir for 10 min to mix evenly. Add 10 mmol of vanadium pentoxide to the above solution and stir for 10 min to mix evenly. Place the above mixed solution in an oil bath at 80 °C and stir for 1 h to obtain a mixture of vanadium oxalate and carbon nanotubes. Freeze-dry the above mixed solution for 48 h.

[0049] Calcination step: After the above precursor is fully ground, it is placed in a muffle furnace and heated to 300°C at a heating rate of 5°C / min and calcined for 3 hours to finally obtain the vanadium oxide-based composite electrode material of this embodiment.

[0050] Structural characterization and performance test results:

[0051] like Figure 1As shown, the prepared vanadium oxide-based composite electrode material exhibits a blocky morphology with particle sizes of tens of micrometers; for example... Figure 2 As shown, the carbon nanotube network is distributed in the vanadium oxide particles, exhibiting a mixed mosaic structure.

[0052] Test results show that the vanadium oxide-based composite electrode material of this embodiment exhibits excellent low-temperature lithium storage performance: at room temperature, it has a specific capacity of 280 mAh / g; at -40°C, it has a specific capacity of 200 mAh / g (50 mA / g current density) and a specific capacity of 95 mAh / g (1000 mA / g current density), and the capacity retention is close to 100% after 300 cycles. Figure 3 and Figure 4 ).

[0053] Example 2

[0054] Precursor preparation: Weigh 50 mg of carbon nanotubes and ultrasonically disperse them in 10 ml of deionized water. Add 30 mmol of oxalic acid and stir for 10 min to mix evenly. Add 10 mmol of vanadium pentoxide to the above solution and stir for 10 min to mix evenly. Place the above mixed solution in an oil bath at 80 °C and stir for 1 h to obtain a mixture of vanadium oxalate and carbon nanotubes. Freeze-dry the above mixed solution for 48 h.

[0055] Calcination step: After the above precursor is fully ground, it is placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min and calcined for 2 hours to finally obtain the vanadium oxide-based composite electrode material of this embodiment.

[0056] Structural characterization and performance test results:

[0057] The prepared vanadium oxide-based composite electrode material exhibits a blocky morphology and particle size similar to that of Example 1;

[0058] Test results show that the specific capacity, rate capability, and cycle stability of the vanadium oxide-based composite electrode material obtained in this embodiment are close to those of Example 1.

[0059] Example 3

[0060] Precursor preparation: Weigh 100 mg of carbon nanotubes and ultrasonically disperse them in 20 ml of deionized water. Add 30 mmol of oxalic acid and stir for 10 min to mix evenly. Add 10 mmol of vanadium pentoxide to the above solution and stir for 10 min to mix evenly. Place the above mixed solution in an oil bath at 80 °C and stir for 1 h to obtain a mixture of vanadium oxalate and carbon nanotubes. Freeze-dry the above mixed solution for 48 h.

[0061] Calcination step: After the above precursor is fully ground, it is placed in a muffle furnace and heated to 250°C at a heating rate of 5°C / min and calcined for 3 hours to finally obtain the vanadium oxide-based composite electrode material of this embodiment.

[0062] Structural characterization and performance test results:

[0063] The prepared vanadium oxide-based composite electrode material exhibits a blocky morphology and particle size similar to that of Example 1;

[0064] Test results show that the specific capacity, rate capability, and cycle stability of the vanadium oxide-based composite electrode material obtained in this embodiment are close to those of Example 1.

[0065] Example 4

[0066] Precursor preparation: Add 30 mmol of oxalic acid to 10 ml of deionized water and stir for 10 min to mix evenly; add 10 mmol of vanadium pentoxide to the above solution and stir for 10 min to mix evenly; place the above mixed solution in an oil bath at 80 °C and stir for 1 h to obtain vanadium oxalate precursor solution; freeze-dry the above solution for 48 h.

[0067] Calcination step: After the above precursor is fully ground, it is placed in a muffle furnace and heated to 300°C at a heating rate of 5°C / min and calcined for 2 hours to finally obtain the vanadium oxide-based composite electrode material of this embodiment.

[0068] Structural characterization and performance test results:

[0069] The prepared vanadium oxide-based composite electrode material exhibits a blocky morphology and particle size similar to that of Example 1;

[0070] Test results show that the specific capacity, rate capability, and cycle stability of the vanadium oxide-based composite electrode material obtained in this embodiment are close to those of Example 1.

[0071] Comparative Example 1

[0072] The preparation method is the same as in Example 1, except that the carbon nanotubes are not acidified during the preparation of the precursor.

[0073] The characterization and experimental results are as follows:

[0074] like Figure 5 , 6 As shown, the prepared vanadium oxide-based composite electrode material exhibits a blocky morphology with particle sizes of tens of micrometers. However, compared to Example 1, the particles are loose and porous, not dense enough, and show obvious nanoparticles; as Figure 7 As shown, compared with Example 1, the rate performance at low temperature is poor and the capacity is low.

[0075] Comparative Example 2

[0076] The preparation method is the same as in Example 1, except that hot air drying is used to remove the solvent from the mixture of vanadium oxalate and carbon nanotubes.

[0077] The characterization and experimental results are as follows:

[0078] like Figure 8 , 9 As shown, the vanadium oxide-based composite electrode material prepared in Example 1 has less dense particles and exhibits obvious nanoparticle agglomeration; Figure 10 As shown, the rate performance at low temperatures is slightly worse compared to Example 1.

Claims

1. A vanadium oxide-based composite material, characterized in that, For lithium storage at temperatures below -40°C, the vanadium oxide-based composite material has an average particle size of any value between 15 and 50 μm and a tap density of 0.8-2 g / cm³. 3 For any value in the range, the specific surface area does not exceed 50 m². 2 / g; The vanadium oxide-based composite material is a hybrid embedded structure of vanadium oxide and carbon nanotubes, wherein the vanadium oxide and the carbon nanotubes are bonded by chemical bonds. The vanadium oxide-based composite material is based on vanadium oxide, with carbon nanotubes as a supporting framework dispersed in the bulk phase of vanadium oxide. The carbon nanotubes serve as electron channels at the grain boundaries of vanadium oxide. The preparation method of the vanadium oxide-based composite material includes a precursor preparation step and a calcination step; The precursor preparation steps include: acidifying carbon nanotubes, dispersing them, adding vanadium-based raw materials and catalysts, stirring thoroughly at 20-120 °C to obtain a precursor solution, and then desolventizing and drying the precursor to obtain the precursor. The method for desolventizing and drying the precursor includes freeze drying.

2. The vanadium oxide-based composite material according to claim 1, characterized in that, The mass fraction of carbon nanotubes in the vanadium oxide-based composite material is any value between 1% and 10%.

3. The vanadium oxide-based composite material according to claim 1, characterized in that, The vanadium oxide is selected from at least one of vanadium dioxide, vanadium pentoxide, vanadium trioxide, vanadium monoxide, and vanadium tridecyloxide; the diameter of the carbon nanotube is any value between 10 and 100 nm, and is selected from single-walled carbon nanotubes or multi-walled carbon nanotubes.

4. The method for preparing the vanadium oxide-based composite material according to any one of claims 1-3, characterized in that, This includes the precursor preparation step and the calcination step; The precursor preparation steps include: acidifying carbon nanotubes, dispersing them, adding vanadium-based raw materials and catalysts, stirring thoroughly at 20-120 °C to obtain a precursor solution, and then desolventizing and drying the precursor to obtain the precursor. The calcination step includes calcining the precursor after solvent removal at a temperature of 200-800℃.

5. The method for preparing the vanadium oxide-based composite material according to claim 4, characterized in that, The vanadium-based raw material is selected from at least one of amine metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium acetylacetonate, vanadium oxalate, vanadium pentoxide, vanadium dioxide, and vanadium trioxide; the catalyst is selected from at least one of oxalic acid, sulfuric acid, phosphoric acid, hydrochloric acid, and acetic acid; the mass ratio of the vanadium-based raw material to the carbon nanotubes is 0.1:1-100:

1.

6. The application of the vanadium oxide-based composite material according to any one of claims 1-3 in electrode materials.

7. A lithium-ion battery, characterized in that, The electrode material of the lithium-ion battery includes the vanadium oxide-based composite material described in any one of claims 1-3.

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