Preparation method of vanadium oxide phosphate nanosheet and application thereof
By preparing ordered mesoporous vanadium oxyphosphate nanosheets, the problem of insufficient capacity and power density of lithium-ion battery cathode materials has been solved, achieving high energy density and high power density lithium-ion battery performance, which has broad application prospects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2022-11-23
- Publication Date
- 2026-06-09
Smart Images
Figure CN118062815B_ABST
Abstract
Description
Technical Field
[0001] This application relates to a method for preparing vanadium oxyphosphate nanosheets and their applications, belonging to the field of materials preparation. Background Technology
[0002] Lithium metal anodes have extremely high theoretical specific capacity (3860 mAh g). -1 Its extremely low electrochemical potential (-3.04V vs. standard hydrogen electrode) makes it the preferred anode material for next-generation high-energy-density lithium batteries. With the development of large electronic devices such as electric vehicles, further improving the energy density and power density of lithium-ion batteries has become a top priority. However, the currently widely used cathode materials are mainly lithium transition metal oxides, with actual capacities typically ranging from 140 to 170 mAh g⁻¹. -1 Furthermore, the rapid capacity decay during high-current charging and discharging is a major factor limiting battery capacity density and power density. Innovating electrode materials and replacing traditional materials with those possessing unique electrochemical properties is one of the important ways to improve battery capacity or voltage.
[0003] To address the aforementioned issues, there is an urgent need to develop materials with multi-electron reaction properties as cathode materials to enable the insertion and extraction of multiple lithium ions, thereby achieving higher specific capacity and subsequently improving energy density. Summary of the Invention
[0004] The purpose of this application is to provide an ordered mesoporous vanadium oxyphosphate nanosheet material. The presence of ordered mesopores in this ordered mesoporous vanadium oxyphosphate nanosheet material effectively improves the lithium-ion transport rate, thereby achieving high specific capacity and high rate performance, and improving the cycle reversibility and stability of multi-electron reactions.
[0005] According to one aspect of this application, a method for preparing vanadium oxyphosphate nanosheets is provided, comprising the following steps:
[0006] A) Dissolve the phosphate anionic surfactant in a mixed solution of ethanol and water to obtain solution I;
[0007] B) Mix the vanadium-containing compound with the solution I and stir. Place the stirred product in a sealed container for reaction, centrifugation, freezing, drying and annealing to obtain ordered mesoporous vanadium oxyphosphate nanosheets.
[0008] The valence state of the vanadium ion is selected from at least one of divalent, trivalent, tetravalent, and pentavalent.
[0009] Optionally, the vanadium-containing compound is selected from at least one of ammonium metavanadate, vanadium oxalate, vanadium oxysulfate, vanadium dichloride, and vanadium nitrate.
[0010] Optionally, the phosphate anionic surfactant is selected from at least one of tetradecyl phosphoric acid, octadecyl phosphoric acid, dodecyl phosphoric acid, and dodecyl dimethyl phosphoric acid.
[0011] Optionally, the concentration of vanadium ions in the vanadium-containing compound is 1–100 mg / mL.
[0012] Optionally, the concentration of vanadium ions in the vanadium-containing compound is any value or a range between two of the following: 1 mg / mL, 10 mg / mL, 25 mg / mL, 50 mg / mL, 75 mg / mL, and 100 mg / mL.
[0013] Optionally, the concentration of the phosphate anionic surfactant in solution I is 0.5–100 mg / mL.
[0014] Optionally, the concentration of the phosphate anionic surfactant in solution I is any value or a range between two values from 0.5 mg / mL, 1 mg / mL, 10 mg / mL, 25 mg / mL, 50 mg / mL, 75 mg / mL, and 100 mg / mL.
[0015] Optionally, the mass ratio of ethanol to water in solution I is 1:0.2 to 5.
[0016] Optionally, the mass ratio of ethanol to water in solution I is any ratio or a range between two ratios from 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, and 1:5.
[0017] Optionally, the molar ratio of the phosphate anionic surfactant to the vanadium-containing compound is 1:1.
[0018] Optionally, the stirring method is as follows: stirring under magnetic stirring for 0.5 to 8 hours.
[0019] Optionally, the reaction conditions are: temperature 120–220°C, time 2–48 h;
[0020] Optionally, the reaction temperature is any value or a range between two of 120°C, 140°C, 180°C, 220°C, and 220°C.
[0021] Optionally, the reaction time is any value among 2h, 10h, 24h, 36h, and 48h, or a range between two values.
[0022] Optionally, the centrifugation speed is 100-1000 r / min, and the centrifugation time is 1-10 min.
[0023] Optionally, the centrifugation speed is any value among 100 r / min, 300 r / min, 500 r / min, 700 r / min, and 1000 r / min, or a range between two values.
[0024] Optionally, the centrifugation time is any value among 1 min, 3 min, 5 min, 7 min, and 10 min, or a range between two values.
[0025] Optionally, the freezing conditions are: temperature -45 to -10°C, time 1 min to 3 h.
[0026] Optionally, the freezing temperature is any value among -45℃, -35℃, -25℃, and -10℃, or a range between two values.
[0027] Optionally, the freezing time is any value among 1 min, 1 h, 2 h, and 3 h, or a range between two values.
[0028] Optionally, the drying conditions are: temperature 40–80°C, time 24–72 h.
[0029] Optionally, the drying temperature is any value among 40°C, 50°C, 60°C, 70°C, and 80°C, or a range between two values.
[0030] Optionally, the drying time is any value among 24h, 48h, and 72h, or a range between two values.
[0031] Optionally, the drying method is any one of freeze drying, room temperature drying, vacuum drying, heating drying, and supercritical drying, wherein the drying medium is water or ethanol.
[0032] Optionally, the annealing conditions are: temperature 200–450°C, time 0.5–5 h, and heating rate 1–10°C / min.
[0033] Optionally, the annealing temperature is any value among 200℃, 250℃, 300℃, 400℃, and 450℃, or a range between two values.
[0034] Optionally, the annealing time is any value among 0.5h, 1h, 2.5h, 3.5h, 4.5h, and 5h, or a range between two values.
[0035] According to another aspect of this application, a vanadium oxyphosphate nanosheet is provided, which is obtained according to the above preparation method, and the vanadium oxyphosphate nanosheet has ordered mesopores.
[0036] Optionally, the vanadium oxyphosphate nanosheets are amorphous vanadium oxyphosphate and / or crystalline vanadium oxyphosphate, and the vanadium oxyphosphate nanosheets include sheet-like and / or ribbon-like shapes.
[0037] According to another aspect of this application, the application of vanadium oxyphosphate nanosheets in high-energy, high-density, and high-power-density lithium-ion battery cathodes is provided, wherein the high energy density ranges from 100 to 400 Wh / kg. -1 The high power density range is 1–10 Wh / kg. -1 .
[0038] Optionally, the method for preparing the positive electrode sheet of the lithium-ion battery includes the following steps:
[0039] a) A mixture containing vanadium oxyphosphate nanosheets, a conductive agent, a binder, and solvent I is ground to obtain a uniform slurry;
[0040] b) Coat the uniform slurry prepared in step a) onto the positive electrode sheet, pre-dry it, and then vacuum dry it to obtain the positive electrode sheet of the lithium-ion battery.
[0041] Optionally, the mass ratio of the vanadium oxyphosphate nanosheets, conductive agent, binder, and solvent I is 1:(0.1-0.2):(0.1-0.2):(0.1-0.4).
[0042] The conductive agent is selected from at least one of acetylene black, Ketjen black, and carbon nanotubes.
[0043] The adhesive is selected from at least one of sodium carboxymethyl cellulose, sodium alginate, polytetrafluoroethylene, and polyvinylidene fluoride;
[0044] Solvent I is selected from water and / or N-methylpyrrolidone.
[0045] Optionally, the positive electrode is selected from aluminum foil or carbon-coated aluminum foil.
[0046] Optionally, the coating thickness is 50–1000 μm.
[0047] Optionally, the pre-drying temperature is 40–80°C, and the pre-drying time is 1–10 hours.
[0048] Optionally, the vacuum drying temperature is 100–120°C, and the vacuum drying time is 10–24 hours.
[0049] The beneficial effects that this application can produce include:
[0050] 1) The method for preparing vanadium oxyphosphate nanosheets provided in this application adopts ion adsorption and constructs an ultrafast lithium-ion transport structure based on the ordered mesoporous structure of vanadium oxyphosphate, which increases the active sites, shortens the electron-ion transport distance, and has excellent electrochemical performance.
[0051] 2) The method for preparing vanadium oxyphosphate nanosheets provided in this application is low in cost, simple to operate, and conducive to industrialization.
[0052] 3) The lithium-ion battery positive electrode sheet provided in this application has excellent rate performance, high battery quality, good performance, and a wide range of applications. Attached Figure Description
[0053] Figure 1 The image shown is a scanning electron microscope (TEM) image of the ordered mesoporous vanadium oxyphosphate nanosheet material in Example 1 of this application.
[0054] Figure 2 These are scanning probe atomic force microscopy (AFM) images of the ordered mesoporous vanadium oxyphosphate nanosheets in Example 1 of this application;
[0055] Figure 3 The charge-discharge curves of the ordered mesoporous vanadium oxyphosphate nanosheets used as a cathode material in lithium-ion batteries in Example 1 of this application are shown.
[0056] Figure 4 The rate performance of the ordered mesoporous vanadium oxyphosphate nanosheet material used as a cathode material in lithium-ion batteries is shown in Example 1 of this application. Detailed Implementation
[0057] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0058] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0059] The analysis method in the embodiments of this application is as follows:
[0060] Under vacuum conditions, scanning electron microscopy (TEM) images of vanadium oxyphosphate / graphene two-dimensional heterojunction materials were obtained using an HT7700.
[0061] Scanning probe atomic force microscopy (AFM) images of vanadium oxyphosphate / graphene two-dimensional heterojunction materials were obtained using NanoWizard under air conditions.
[0062] The charge-discharge curves of vanadium oxyphosphate / graphene two-dimensional heterojunction material used as a cathode material in lithium-ion batteries were analyzed using the LAND battery testing system.
[0063] The rate performance of vanadium oxyphosphate / graphene two-dimensional heterojunction material used as a cathode material in lithium-ion batteries was analyzed using the LAND battery testing system.
[0064] As a specific implementation method, a vanadium-containing compound and a solution containing a phosphate anionic surfactant are used as raw materials. Vanadium ions are electrostatically adsorbed onto the surface of the phosphate anionic surfactant, which self-assembles into nanosheets, via ion adsorption. The resulting material is then subjected to hydrothermal treatment, centrifugation, freeze-drying, and annealing to obtain ordered mesoporous vanadium oxyphosphate nanosheets. The ion adsorption method involves stirring under magnetic stirring for varying times, ranging from 0.5 to 8 hours.
[0065] A method for preparing ordered mesoporous vanadium oxyphosphate nanosheets as positive electrode material for lithium-ion batteries, characterized in that the method includes the following steps:
[0066] (1) The ordered mesoporous vanadium oxyphosphate nanosheets, conductive agent, and binder are ground into a uniform slurry using solvent I;
[0067] (2) Apply the slurry to aluminum foil / carbon-coated aluminum foil with a scraper to a thickness of 50-1000 micrometers;
[0068] (3) After pre-baking the coated aluminum foil / carbon-coated aluminum foil for 1-5 hours, heat up and vacuum dry for 10-24 hours, then cut it into electrode sheets with a diameter of 10 mm or 12 mm.
[0069] The ordered mesoporous vanadium oxyphosphate nanosheet material comprises a two-dimensional amorphous or crystalline vanadium oxyphosphate nanosheet structure. When used as a cathode material for lithium-ion batteries, this ordered mesoporous vanadium oxyphosphate nanosheet material exhibits ultra-high specific capacity and excellent rate performance. This preparation method utilizes inexpensive raw materials, is easily scaled up, requires simple equipment, is highly efficient, and has a high reproducibility rate, making the prepared lithium-ion batteries promising for future applications.
[0070] Example 1
[0071] Ammonium metavanadate was prepared into a 1 mol / L aqueous solution. The precursor solution and an ethanol / water solution of 0.5 mol / L dodecylphosphonic acid (ethanol to water volume ratio of 1:2) were magnetically stirred for 3 h at a volume ratio of 1:2. The mixed solution was placed in a 100 mL hydrothermal reactor and kept at 180 °C for 24 h. After centrifugation, the solution was freeze-dried and then annealed in air at a heating rate of 5 °C / min for 2 h to obtain crystalline ordered mesoporous vanadium oxyphosphate nanosheets.
[0072] Ordered mesoporous vanadium oxyphosphate nanosheets (mass ratio 1:0.1:0.1:0.3), conductive agent acetylene black, and binder polyvinylidene fluoride were ground into a uniform slurry using N-methylpyrrolidone as solvent. The slurry was then coated onto aluminum foil / carbon-coated aluminum foil to a thickness of 100 micrometers using a doctor blade. The coated aluminum foil / carbon-coated aluminum foil was pre-baked at 70°C for 3 hours, then heated to 100°C under vacuum for 10 hours to dry completely before being cut into electrode sheets with a diameter of 12 mm. This positive electrode sheet was then assembled with a lithium-ion cell to form a lithium-ion battery.
[0073] The resulting lithium-ion battery can operate stably within a voltage range of 1.5-4.5V, exhibiting extremely high rate capability and good cycle life.
[0074] Example 2
[0075] Vanadium oxalate was prepared into a 2 mol / L aqueous solution. The precursor solution and a 1 mol / L tetradecylphosphonic acid ethanol / water solution (ethanol to water volume ratio of 1:3) were magnetically stirred at a volume ratio of 1:2 for 3 h. The mixed solution was placed in a 100 mL hydrothermal reactor and kept at 180 °C for 24 h. After centrifugation, the solution was freeze-dried and then annealed in air at a heating rate of 5 °C / min for 2 h to obtain crystalline ordered mesoporous vanadium oxalate nanosheets.
[0076] Ordered mesoporous vanadium oxyphosphate nanosheets (mass ratio 1:0.1:0.1:0.3), conductive agent acetylene black, and binder polyvinylidene fluoride were ground into a uniform slurry using N-methylpyrrolidone as solvent. The slurry was then coated onto aluminum foil / carbon-coated aluminum foil to a thickness of 100 micrometers using a doctor blade. The coated aluminum foil / carbon-coated aluminum foil was pre-baked at 70°C for 3 hours, then heated to 100°C under vacuum for 10 hours to dry completely before being cut into electrode sheets with a diameter of 12 mm. This positive electrode sheet was then assembled with a lithium-ion cell to form a lithium-ion battery.
[0077] The resulting lithium-ion battery can operate stably within a voltage range of 1.5-4.5V, exhibiting extremely high rate capability and good cycle life.
[0078] Example 3
[0079] Vanadium pentoxide was dissolved in hydrogen peroxide to prepare a 1 mol / L aqueous solution. The precursor solution and an ethanol / water solution of 1 mol / L octadecylphosphonic acid (ethanol to water volume ratio of 1:3) were magnetically stirred at a volume ratio of 1:1 for 3 h. The mixed solution was placed in a 100 mL hydrothermal reactor and kept at 180 °C for 24 h. After centrifugation, the solution was freeze-dried and then annealed in air at a heating rate of 5 °C / min for 2 h to obtain crystalline ordered mesoporous vanadium oxyphosphate nanosheets.
[0080] Ordered mesoporous vanadium oxyphosphate nanosheets (mass ratio 1:0.1:0.1:0.3), conductive agent acetylene black, and binder polyvinylidene fluoride were ground into a uniform slurry using N-methylpyrrolidone as solvent. The slurry was then coated onto aluminum foil / carbon-coated aluminum foil to a thickness of 100 micrometers using a doctor blade. The coated aluminum foil / carbon-coated aluminum foil was pre-baked at 70°C for 3 hours, then heated to 100°C under vacuum for 10 hours to dry completely before being cut into electrode sheets with a diameter of 12 mm. This positive electrode sheet was then assembled with a lithium-ion cell to form a lithium-ion battery.
[0081] The resulting lithium-ion battery can operate stably within a voltage range of 1.5-4.5V, exhibiting extremely high rate capability and good cycle life.
[0082] Example 4
[0083] Vanadium oxalate was prepared into a 2 mol / L aqueous solution. The precursor solution and a 1 mol / L tetradecylphosphonic acid ethanol / water solution (ethanol to water volume ratio of 1:3) were magnetically stirred at a volume ratio of 1:2 for 3 h. The mixed solution was placed in a 100 mL hydrothermal reactor and kept at 180 °C for 24 h. After centrifugation, the solution was freeze-dried and then annealed in air at a heating rate of 5 °C / min for 2 h to obtain amorphous ordered mesoporous vanadium oxalate nanosheets.
[0084] Ordered mesoporous vanadium oxyphosphate nanosheets (mass ratio 1:0.1:0.1:0.3), conductive agent acetylene black, and binder polyvinylidene fluoride were ground into a uniform slurry using N-methylpyrrolidone as solvent. The slurry was then coated onto aluminum foil / carbon-coated aluminum foil to a thickness of 100 micrometers using a doctor blade. The coated aluminum foil / carbon-coated aluminum foil was pre-baked at 70°C for 3 hours, then heated to 100°C under vacuum for 10 hours to dry completely before being cut into electrode sheets with a diameter of 12 mm. This positive electrode sheet was then assembled with a lithium-ion cell to form a lithium-ion battery.
[0085] The resulting lithium-ion battery can operate stably within a voltage range of 1.5-4.5V, exhibiting extremely high rate capability and good cycle life.
[0086] Figure 1 The image shown is a transmission electron microscopy (TEM) image of the mesoporous vanadium oxyphosphate nanosheets prepared in Example 1, i.e., a transmission electron microscopy (TEM) image of the mesoporous vanadium oxyphosphate nanosheets, according to... Figure 1 It can be seen that the surface of the nanosheet has uniformly distributed mesopores with a size of about 7 nm.
[0087] Figure 2 The image shown is a scanning probe atomic force microscope (AFM) image of mesoporous vanadium oxyphosphate nanosheets from Example 1. Figure 2 It can be determined that the thickness of the mesoporous nanosheet is approximately 2 nm.
[0088] Figure 3 The charge-discharge curves of the mesoporous vanadium oxyphosphate nanosheets used as a cathode material in Example 1 are shown below. Figure 3 It can be seen that the nanosheet has two discharge ramps at around 2V and 3.7V.
[0089] Figure 4 The rate performance of the mesoporous vanadium oxyphosphate nanosheets used as a cathode material in Example 1 for lithium-ion batteries is based on... Figure 4 It can be seen that the nanosheet has a good rate capability when used as a positive electrode material.
[0090] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing vanadium oxyphosphate nanosheets, characterized in that, Includes the following steps: A) Dissolve the phosphate anionic surfactant in a mixed solution of ethanol and water to obtain solution I; B) Mix the vanadium-containing compound with the solution I and stir. Place the stirred product in a sealed container for reaction, centrifugation, freezing, drying and annealing to obtain vanadium oxyphosphate nanosheets with ordered mesoporous structures. The valence state of the vanadium ion is selected from at least one of divalent, trivalent, tetravalent, and pentavalent. The phosphate anionic surfactant is selected from at least one of tetradecylphosphonic acid, octadecylphosphonic acid, dodecylphosphonic acid, and dodecyl dimethylphosphonic acid.
2. The preparation method according to claim 1, characterized in that, The vanadium-containing compound is selected from at least one of ammonium metavanadate, vanadium oxalate, vanadium oxalate sulfate, vanadium dichloride, vanadium nitrate, and vanadium trichloride.
3. The preparation method according to claim 1, characterized in that, The concentration of vanadium ions in the vanadium-containing compound is 1~100 mg / mL.
4. The preparation method according to claim 1, characterized in that, The concentration of the phosphate anionic surfactant in solution I is 0.5~100 mg / mL.
5. The preparation method according to claim 1, characterized in that, The mass ratio of ethanol to water in solution I is 1:0.2~5.
6. The preparation method according to claim 1, characterized in that, The molar ratio of the phosphate anionic surfactant to the vanadium-containing compound is 1:
1.
7. The preparation method according to claim 1, characterized in that, The stirring method is as follows: stirring under magnetic stirring for 0.5~8 hours.
8. The preparation method according to claim 1, characterized in that, The reaction conditions are: temperature 120~220℃, time 2~48h.
9. The preparation method according to claim 1, characterized in that, The centrifugation speed is 100~1000 r / min, and the centrifugation time is 1~10 min.
10. The preparation method according to claim 1, characterized in that, The freezing conditions are: temperature -45~-10℃, time 1min~3h.
11. The preparation method according to claim 1, characterized in that, The drying conditions are: temperature 40~80℃, time 24~72h.
12. The preparation method according to claim 1, characterized in that, The annealing conditions are: temperature 200~450℃, time 0.5~5h, and heating rate 1~10℃ / min.
13. A vanadium oxyphosphate nanosheet obtained by the preparation method according to any one of claims 1 to 12, characterized in that, The vanadium oxyphosphate nanosheets have ordered mesopores.
14. The application of the vanadium oxyphosphate nanosheets according to claim 13 in the positive electrode of a lithium-ion battery.
15. The application according to claim 14, characterized in that, The method for preparing the positive electrode sheet of the lithium-ion battery includes the following steps: a) A mixture containing vanadium oxyphosphate nanosheets, a conductive agent, a binder, and solvent I is ground to obtain a uniform slurry; b) Coat the uniform slurry prepared in step a) onto the positive electrode sheet, pre-dry it, and then vacuum dry it to obtain the positive electrode sheet of the lithium-ion battery.
16. The application according to claim 15, characterized in that, The mass ratio of the vanadium oxyphosphate nanosheets, conductive agent, binder, and solvent I is 1:(0.1~0.2):(0.1~0.2):(0.1~0.4). The conductive agent is selected from at least one of acetylene black, Ketjen black, and carbon nanotubes. The adhesive is selected from at least one of sodium carboxymethyl cellulose, sodium alginate, polytetrafluoroethylene, and polyvinylidene fluoride; Solvent I is selected from water and / or N-methylpyrrolidone.
17. The application according to claim 15, characterized in that, The positive electrode is selected from aluminum foil or carbon-coated aluminum foil.
18. The application according to claim 15, characterized in that, The coating thickness is 50~1000μm.
19. The application according to claim 15, characterized in that, The pre-drying temperature is 40~80℃, and the pre-drying time is 1~10h.
20. The application according to claim 15, characterized in that, The vacuum drying temperature is 100~120℃, and the vacuum drying time is 10~24h.