Preparation method of vanadium oxide positive electrode with large interplanar spacing and high conductivity

Abstract

The invention discloses a method for preparing vanadium oxide nanoparticle microspheres with large interplanar spacing and high conductivity. The method mainly comprises the following steps: S1, by taking vanadium oxide as a vanadium ion source and hydrogen peroxide as an oxidizing agent, uniformly mixing the vanadium oxide ion source and a copper ion source with the hydrogen peroxide, putting the mixture into a hydrothermal reaction kettle, and reacting for 5-7 hours at 100-140 DEG C to obtain a reaction solution; copper ion embedded vanadium oxide (CuVO) nano particle microspheres containing oxygen vacancies are obtained; cuVO is used as a precursor, aniline is used as a monomer of a polymer, polyaniline is polymerized on the surface of CuVO in situ, and CuVO-coated PANI nano particle microspheres are obtained. The method is simple and mild and can be applied on a large scale. The CuVO-coated PANI keeps a large interplanar spacing of 1.61 nm, and also has high conductivity (the resistance is 9.6 ohm) which is far greater than the conductivity (the resistance is 93.4 ohm) of CuVO. The newly prepared CuVO-coated PANI has the 3D morphology of nano particle microspheres, and high specific surface area and conductivity are realized.

Description

Technical Field

[0001] This invention belongs to the field of new energy battery technology, and relates to an aqueous zinc-ion battery, specifically to a method for preparing a vanadium oxide cathode that combines large crystal interplanar spacing and high conductivity. Background Technology

[0002] The advantages of aqueous zinc-ion batteries (ZIBs) are mainly reflected in their high safety, low cost, environmental friendliness, and excellent rate performance and cycle stability. These batteries use water as the electrolyte, combining the advantages of safety (no risk of explosion or combustion), low raw material cost, and simple manufacturing process. Furthermore, technological innovation has achieved high specific capacity and long cycle life, making them promising for applications in energy storage, new energy, and other fields.

[0003] The electrochemical performance of the cathode material determines the energy density of ZnI. Currently, commonly used cathode materials mainly include manganese oxide, vanadium oxide, and Prussian blue analogues. Among them, vanadium oxide has attracted much attention due to its unique layered structure and diverse valence states. However, its small interplanar spacing (0.44 nm) and poor conductivity hinder the development of ZnI. 2+ The dynamic reaction process of transport limits the development of ZIB.

[0004] Existing technologies mainly utilize intercalation of cations (such as Na) between layers. + NH4 + Increase the interplanar spacing to 0.6–0.9 nm (e.g., NH4V4O) 10 However, the electronic conductivity of the intercalated materials is generally lower than 10. -3 The low S / cm ratio limits rate performance (capacity <200 mAh / g at 1 A / g). Furthermore, ion-intercalated vanadium oxide is prone to structural collapse, resulting in significant vanadium dissolution during cycling and poor cycle stability. While existing modification methods (carbon coating, metal doping) can partially improve conductivity, they sacrifice interlayer spacing advantages, making it difficult to balance energy density and cycle stability. Additionally, physically coating conductive materials onto the vanadium oxide surface can partially improve conductivity, but the carbon layer blocks ion channels and lacks the stabilizing effect of chemical bonds, leading to decreased cycle stability.

[0005] Current research on the modification of vanadium oxide cathode materials mainly focuses on two directions: interplanar spacing control and conductivity improvement. Regarding interplanar spacing control, this is primarily achieved through metal ion embedding into the interlayer of vanadium oxide (0.9-1.2 nm), but this method generally suffers from insufficient conductivity (conductivity <10). - ³ S / cm). Conductivity enhancement technologies mainly utilize carbon coating and conductive polymer modification, which can increase conductivity to 10. -¹ The efficiency is on the order of S / cm, but this often sacrifices the interlayer spacing advantage of the material. Existing technologies have two key problems: 1) poor bonding stability between dopant ions and the matrix; 2) weak interfacial bonding between the conductive modification layer and vanadium oxide, leading to structural collapse during charging and discharging. Summary of the Invention

[0006] To address the issues of small interplanar spacing and low conductivity in vanadium oxide, this invention provides a method for preparing vanadium oxide nanoparticles / microspheres that simultaneously possess large interplanar spacing and high conductivity. This method primarily utilizes a combination of hydrothermal synthesis and in-situ polymerization of conductive polymers. This approach is simple, mild, and suitable for large-scale application.

[0007] The objective of this invention is achieved through the following technical solution: A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 100℃-140℃ for 5-7 hours to obtain vanadium oxide (CuVO) nanoparticles containing copper ions with oxygen vacancies. S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline was polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres.

[0008] In the above-mentioned method for preparing vanadium oxide cathodes that combine large interplanar spacing and high conductivity, the copper source in step S1 is any one of copper chloride, copper nitrate, or copper sulfate.

[0009] In the above-mentioned method for preparing vanadium oxide cathode with both large interplanar spacing and high conductivity, in step S1, the molar ratio of copper ions: vanadium ions: hydrogen peroxide is (1-2): (2-4): (0.02-0.04), and the reaction is carried out at 120℃ for 6 hours to obtain vanadium oxide (CuVO) nanoparticles microspheres containing copper ions embedded with oxygen vacancies.

[0010] In the above-mentioned method for preparing vanadium oxide cathode with both large interplanar spacing and high conductivity, in step S2, the molar ratio of the precursor to the monomer of the polymer is (40-50): (0.03-0.04).

[0011] Compared with the prior art, the present invention has the following technical effects: 1. Research has found that the interplanar spacing of CuVO increases to 1.61 nm, which is much larger than the interplanar spacing of pure V₂O₅ (0.44 nm), accelerating the Zn crystallization process. 2+The transport kinetics process. CuVO@PANI maintains a large interplanar spacing of 1.61 nm and also has high conductivity (resistance of 9.6 Ω), which is much greater than that of CuVO (resistance of 93.4 Ω).

[0012] 2. The newly prepared CuVO@PANI has a 3D morphology of nanoparticle microspheres, achieving high specific surface area and conductivity.

[0013] 3. The CuVO@PANI structure contains abundant Cu-NO chemical bonds, which enable PANI polyaniline to be chemically bonded to the CuVO surface, improving structural stability, enhancing interfacial electronic coupling, and constructing a fast electron transport channel.

[0014] 4. CuVO@PANI electrode at 0.1 A g -1 672.2 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a yield of 269.2 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0015] 5. CuVO@PANI electrode yielded 672.2 mAh g⁻¹ -1 Its ultra-high specific capacity.

[0016] 6. This invention utilizes a combination of hydrothermal method and in-situ polymerization of conductive polymers. This method is simple, mild, and can be applied on a large scale. Attached Figure Description

[0017] Figure 1 This is a morphology diagram of the CuVO@PANI nanoparticle microspheres of the present invention.

[0018] Figure 2 This is the XRD curve of CuVO@PANI, CuVO-PANI, and CuVO of the present invention.

[0019] Figure 3 This is a resistance value diagram of CuVO@PANI, CuVO-PANI, and CuVO of the present invention.

[0020] Figure 4 The present invention relates to CuVO@PANI, CuVO-PANI, and CuVO electrodes in 0.1Ag. -1 Cyclic stability ratio diagram.

[0021] Figure 5 The CuVO@PANI electrode of this invention is at 6 A g -1 Cyclic stability ratio diagram. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Example 1 A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 100℃-140℃ for 5-7 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies. The copper source is any one of copper chloride, copper nitrate, or copper sulfate. The molar ratio of copper ions:vanadium ions:hydrogen peroxide is (1-2):(2-4):(0.02-0.04). The mixture is reacted at 120℃ for 6 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies.

[0025] S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline is polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres. The molar ratio of the precursor to the polymer monomer is (40-50): (0.03-0.04).

[0026] The CuVO@PANI structure contains abundant Cu-NO chemical bonds, enhancing interfacial electronic coupling and constructing a rapid electron transport channel. The CuVO@PANI electrode at 0.1 A g... -1 672.2 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a yield of 269.2 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0027] Example 2 A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and the copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 120°C for 6 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies. The copper source is copper chloride, and the molar ratio of copper ions:vanadium ions:hydrogen peroxide is 1.5:3:0.03. The mixture is reacted at 120°C for 6 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies.

[0028] S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline is polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres, wherein the molar ratio of the precursor to the polymer monomer is 45:0.035.

[0029] The CuVO@PANI structure contains abundant Cu-NO chemical bonds, enhancing interfacial electronic coupling and constructing a rapid electron transport channel. The CuVO@PANI electrode at 0.1 A g... -1 672.2 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a yield of 269.2 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0030] Example 3 A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 100°C for 5 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies. The copper source is copper nitrate, and the molar ratio of copper ions:vanadium ions:hydrogen peroxide is 1:2:0.02. The mixture is reacted at 120°C for 6 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies.

[0031] S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline is polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres, wherein the molar ratio of the precursor to the polymer monomer is 40:0.03.

[0032] The CuVO@PANI structure contains abundant Cu-NO chemical bonds, enhancing interfacial electronic coupling and constructing a rapid electron transport channel. The CuVO@PANI electrode at 0.1 A g... -1 676.8 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a yield of 275.4 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0033] Example 4 A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 110°C for 5.5 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies. The copper source is copper sulfate, and the molar ratio of copper ions:vanadium ions:hydrogen peroxide is 1.2:2.2:0.03.

[0034] S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline is polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres. The molar ratio of the precursor to the polymer monomer is 44:0.035.

[0035] The CuVO@PANI structure contains abundant Cu-NO chemical bonds, enhancing interfacial electronic coupling and constructing a rapid electron transport channel. The CuVO@PANI electrode at 0.1 A g... -1 656.7 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a yield of 264.3 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0036] Example 5 A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 130°C for 6.5 hours to obtain vanadium oxide (CuVO) nanoparticles with copper ion embedding containing oxygen vacancies. The copper source is copper chloride, and the molar ratio of copper ions:vanadium ions:hydrogen peroxide is 1.8:3.5:0.035.

[0037] S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline is polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres. The molar ratio of the precursor to the polymer monomer is 48:0.035.

[0038] The CuVO@PANI structure contains abundant Cu-NO chemical bonds, enhancing interfacial electronic coupling and constructing a rapid electron transport channel. The CuVO@PANI electrode at 0.1 A g... -1 668.9 mAh g -1 The ultra-high specific capacity, and at 6 A g -1 It still maintains a capacity of 259.3 mAh g after 2000 cycles. -1 Its high specific capacity enables ultra-high rate capability.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a vanadium oxide cathode that combines large interplanar spacing and high conductivity, characterized in that, Includes the following steps: S1. Using vanadium oxide as the vanadium ion source and hydrogen peroxide as the oxidant, the vanadium oxide ion source and copper ion source are mixed evenly with hydrogen peroxide and placed in a hydrothermal reactor. The mixture is reacted at 100℃-140℃ for 5-7 hours to obtain vanadium oxide (CuVO) nanoparticles containing copper ions with oxygen vacancies. S2. Using CuVO as a precursor and aniline as a polymer monomer, polyaniline was polymerized in situ onto the surface of CuVO to obtain CuVO@PANI nanoparticle microspheres.

2. The method for preparing a vanadium oxide cathode with both large interplanar spacing and high conductivity according to claim 1, characterized in that, In step S1, the copper source is any one of copper chloride, copper nitrate, or copper sulfate.

3. The method for preparing a vanadium oxide cathode with both large interplanar spacing and high conductivity according to claim 1, characterized in that, In step S1, the molar ratio of copper ions: vanadium ions: hydrogen peroxide is (1-2): (2-4): (0.02-0.04). The reaction is carried out at 120°C for 6 hours to obtain vanadium oxide (CuVO) nanoparticles containing copper ions with oxygen vacancies.

4. The method for preparing a vanadium oxide cathode with both large interplanar spacing and high conductivity according to claim 1, characterized in that: In step S2, the molar ratio of the precursor to the polymer monomer is (40-50): (0.03-0.04).

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