Red reed-shaped self-assembly layered structure Na0. 64V2O5 zinc ion battery positive electrode material and preparation method thereof

Abstract

The invention relates to a reed-shaped self-assembly layered structure Na0. 64V2O5 zinc ion battery positive electrode material and a preparation method thereof. The preparation method comprises the following steps: uniformly dissolving NH4VO3 in a mixed solvent of water and ethylene glycol, and recording the solution as a solution A; adding sodium carboxymethyl cellulose and sodium alginate into the solution A to obtain a solution B, heating and uniformly stirring the solution B until the solution is light yellow, then adjusting the pH value, placing the solution in a reaction kettle, and reacting at high temperature to obtain a suspension; and naturally cooling the suspension to room temperature, carrying out vacuum suction filtration, alternately cleaning with water and ethanol to obtain a black precipitate, and carrying out vacuum drying to obtain the Na0. 64V2O5 zinc ion battery positive electrode material. Na in sodium carboxymethyl cellulose and sodium alginate is used for replacing NH4 < + >, through assistance of ethylene glycol, the viscosity of a mixed solution is increased, nucleation and growth of crystal grains are promoted, the needed morphology is obtained, the prepared electrode material Na0. 64V2O5 increases the interlayer spacing of the electrode material, active sites for deintercalation of zinc ions are increased, and the electrochemical performance of the electrode material is improved. And the specific capacity and the rate capability of the electrode material are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc ion battery positive electrode materials, and particularly relates to a reed-like self-assembled layered structure Na 0.64 V2O5 zinc ion battery positive electrode material and preparation method thereof. Background Art

[0002] While traditional fossil fuels (coal, oil, and natural gas) remain the primary energy source in today's society, the greenhouse gases they produce exacerbate global warming. Overreliance on fossil fuels also poses challenges such as air pollution and resource depletion. Against this backdrop, renewable energy sources, such as wind and solar, are attracting significant attention due to their cleanliness and sustainability. However, the utilization of renewable energy sources places higher demands on energy storage technology, necessitating the development of high-energy-density, long-life, and low-cost energy storage systems to ensure a stable energy supply.

[0003] Among the many energy storage technologies, rechargeable batteries have become a research focus due to their high energy conversion efficiency and flexible application scenarios. Lithium-ion batteries (LIBs) dominate the market due to their high energy density (>200Wh / kg) and mature industrial chain. However, the scarcity of lithium resources, the flammability of organic electrolytes, and the growth of lithium dendrites have limited their large-scale energy storage applications. In recent years, aqueous zinc-ion batteries (AZIBs) have attracted widespread attention due to their unique advantages: the theoretical specific capacity of the zinc anode is as high as 820mAh g-1, the redox potential is low (relative to the standard hydrogen electrode, the voltage is -0.76V), and the aqueous electrolyte has no risk of explosion and is environmentally friendly, making it show great potential in the field of large-scale energy storage. However, the performance of zinc-ion batteries is highly dependent on the structural stability and ion transfer efficiency of the cathode material. Currently, the development of high-performance cathode materials that match the zinc anode has become a hot topic for researchers.

[0004] The current mainstream cathode materials include manganese-based oxides, vanadium-based compounds, Prussian blue analogs and organic sulfides. Among them, vanadium-based materials have a variety of oxidation states (V 2+ / V 3+ V 4+ / V 5+ ) and an open framework structure, exhibiting a high theoretical specific capacity (~300 mAh g -1 For example, the layered structure of V2O5 can be formed by Zn 2+ The insertion / extraction of Zn realizes charge storage, but the multivalent Zn 2+ The strong electrostatic interaction between vanadium and V2O5 crystal structure leads to slow ion diffusion kinetics, and interlayer collapse and by-product generation are prone to occur during the cycle, resulting in rapid capacity decay. In addition, the electronic conductivity of vanadium-based materials is low (~10 -6S cm -1 ) further limits their rate performance. Balancing long-cycle stability and high-rate performance in vanadium-based materials remains challenging. In summary, developing vanadium-based cathode materials that combine high specific capacity, fast ion transport, and structural stability is key to breaking through the technological bottleneck of zinc-ion batteries. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a reed-like self-assembled layered structure Na 0.64 V2O5 zinc ion battery positive electrode material and its preparation method solve the problems of poor structural stability and low conductivity of vanadium-based compounds in the prior art. The prepared Na 0.64 V2O5 zinc ion battery positive electrode material has the characteristics of good electrochemical performance, high rate performance, good cycle stability and high specific capacity.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A reed-like self-assembled layered structure Na 0.64 The preparation method of V2O5 zinc ion battery positive electrode material comprises the following steps:

[0008] Step 1, dissolve NH4VO3 uniformly in a mixed solvent of water and ethylene glycol to obtain NH4 + NH4VO3 solution with a concentration of 0.02-0.08 mol / L, marked as solution A;

[0009] Step 2: Take 80 mL of solution A, add 0.01-0.1 g of sodium carboxymethyl cellulose and 0.005-0.02 g of sodium alginate to obtain solution B;

[0010] Step 3, heating the B solution at 60-80° C. and stirring uniformly until the solution turns light yellow;

[0011] Step 4, adjusting the pH value of the light yellow solution obtained in step 3 to 3-5;

[0012] Step 5: placing the solution obtained in step 4 in a reaction kettle and reacting at a hydrothermal temperature of 160-180° C. for 6-24 hours to obtain a suspension;

[0013] Step 6: After the suspension is naturally cooled to room temperature, vacuum filtration is performed, and the suspension is alternately washed with water and ethanol to obtain a black precipitate. The black precipitate is vacuum dried at 60-80° C. to obtain a reed-like self-assembled layered structure sodium vanadate zinc ion battery positive electrode material.

[0014] Furthermore, in the mixed solvent of step 1, the volume ratio of ethylene glycol to water is (0.5-3): (7-9.5).

[0015] Furthermore, the temperature of the mixed solvent in step 1 is 60-80°C.

[0016] Furthermore, the viscosity of the sodium carboxymethyl cellulose in step 2 is 300 to 800 mPa·s.

[0017] Furthermore, in step 2, 0.005 to 0.02 g of a surfactant is added, and the surfactant is specifically one or more of sodium lauryl sulfate, chitosan quaternary ammonium salt, sodium dodecylbenzenesulfonate, sodium octadecyl sulfate or sodium stearate.

[0018] Furthermore, the heating method in step 3 is water bath heating, and the heating and stirring time is 15 to 30 minutes.

[0019] Furthermore, in step 4, dilute hydrochloric acid with a concentration of 0.2 to 1 mol / L is added to adjust the pH value.

[0020] Furthermore, in step 6, the vacuum filtration is performed using a 0.2 μm organic nylon filter membrane.

[0021] Furthermore, the vacuum drying in step 6 adopts an electric vacuum drying oven.

[0022] A reed-like self-assembled layered structure Na 0.64 Na with reed-like self-assembled layered structure prepared by the preparation method of V2O5 zinc ion battery positive electrode material 0.64 V2O5 zinc ion battery positive electrode material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention generates a hydrothermal reaction in a mixed solvent of water and ethylene glycol, and introduces Na into NH4VO3 through sodium carboxymethyl cellulose and sodium alginate to replace NH4 + . Adjusting the pH to 3-5 can improve the crystallinity of the material and promote crystal growth. Under acidic conditions, sodium alginate can also coordinate with vanadium through its carboxylic acid group to regulate the morphology and dispersibility of the nanoparticles. The addition of ethylene glycol can increase the viscosity of the mixed solution and accelerate the nucleation rate of the material. At the same time, ethylene glycol will adhere to specific crystal surfaces and promote the preferential growth of the material, solving the problem of uneven growth and irregular morphology of the material due to the high fluidity and surface tension of water during hydrothermal synthesis of a single aqueous solution. In this way, Na nanoparticles with reed-like nanowire self-assembly layered morphology are prepared. 0.64V2O5 electrode material expands the material interlayer spacing, thereby increasing the contact area between the electrolyte and the electrode active material, increasing the material's active sites, improving the material's specific capacity as a positive electrode material for zinc-ion batteries, and enhancing the battery's charge and discharge capabilities. The preparation process is simple and easy to control, with low cost and little impact on the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The Na prepared in Example 1 of the present invention 0.64 XRD pattern of V2O5;

[0026] Figure 2 The Na prepared in Example 1 of the present invention 0.64 SEM image of V2O5;

[0027] Figure 3 This is a rate performance diagram of a CR2032 button cell assembled from a sample prepared in Example 1 of the present invention;

[0028] Figure 4 This is a cycle performance diagram of a CR2032 button battery assembled with samples prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described in further detail below with reference to the accompanying drawings.

[0030] In each embodiment, the heating and stirring in step 3 needs to use a DF-101S heat-collecting constant temperature heating magnetic stirrer, the vacuum filtration in step 5 needs to use a 0.2um organic nylon filter membrane for filtration, and the vacuum drying needs to use an electric vacuum drying oven.

[0031] Example 1:

[0032] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 80°C, wherein the volume of ethylene glycol is 160 mL and the volume of water is 640 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.0625 mol / L, marked as solution A;

[0033] Step 2: Take 80 mL of solution A, add 0.02 g of sodium carboxymethyl cellulose with a viscosity of 300 mPa·s and 0.005 g of sodium alginate to obtain solution B;

[0034] Step 3, heating the B solution to 80° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stirring for 30 minutes;

[0035] Step 4: Add 0.2 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 3;

[0036] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 180° C. for 24 hours to obtain a suspension;

[0037] Step 6: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 80°C for 24 hours to obtain a flaky Na 0.64 V2O5 zinc ion battery electrode material.

[0038] from Figure 1 The XRD patterns shown in FIG. 0.64 V2O5 crystal material has good crystallinity, high purity, and no other impurities appear; Figure 2 The SEM photos shown in FIG. 0.64 The V2O5 sample presents a large number of nanowire morphologies, and the nanowires self-assemble into sheets with clear edges and compact structures. Numerous nanowires gather together, and the morphology is similar to that of reeds.

[0039] The sample of the present invention is named Na 0.64 V2O5-EG, combined with zinc sheet to form a half-cell, the electrolyte is 3MZn(CF3SO3)2, and 1wt% glycine is added. The positive electrode material of the comparative battery is Na 0.64 V2O5, other conditions remain unchanged. Figure 3 As shown in the rate performance diagram, at a current density of 0.1A g -1 The specific capacity reaches 399 mAh g -1 , at 0.2, 0.5, 1 and 2A g -1 , the specific capacities are 335, 255, 215, and 168 mAh g -1 When the current density drops to 0.1 A g -1 When the capacity is restored to 345mAh g -1 At each current density, the specific capacity is better than that of Na 0.64 The V2O5 sample has excellent rate performance. This indicates that the material has a stable crystal structure and strong electrochemical reversibility under high current. Figure 4 The cycle performance diagram shown in the figure shows that the current density is 1A g -1 When the material is activated gradually, the specific capacity reaches 296.57 mAh g -1 , significantly higher than Na 0.64 220mAh g of V2O5 -1 , and the coulombic efficiency is still 100% after 600 cycles, indicating that the material has good cycle performance and the structure will not collapse during charge and discharge. Figure 3 、4 It can be seen that the reed-like self-assembled layered structure Na 0.64 V2O5 can provide more active sites and better contact with the electrolyte, thereby achieving an increase in specific capacity and improved rate performance. For both batteries, glycine can adsorb on the surface of the zinc anode to form a ZnS-rich SEI layer, inhibiting dendrite growth and HER.

[0040] Example 2:

[0041] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 60°C, wherein the volume of ethylene glycol is 40 mL and the volume of water is 760 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.02 mol / L, marked as solution A;

[0042] Step 2: Take 80 mL of solution A and add 0.04 g of sodium carboxymethyl cellulose with a viscosity of 400 mPa·s, 0.01 g of sodium alginate, and 0.02 g of chitosan quaternary ammonium salt to obtain solution B;

[0043] Step 3, heating the B solution to 60° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stirring for 25 minutes;

[0044] Step 4, adding 0.3 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 4;

[0045] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 160° C. for 18 hours to obtain a suspension;

[0046] Step 5: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 60°C for 24 hours to obtain flaky Na 0.64 V2O5 zinc ion battery electrode material.

[0047] Example 3:

[0048] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 65°C, wherein the volume of ethylene glycol is 80 mL and the volume of water is 720 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.04 mol / L, marked as solution A;

[0049] Step 2: Take 80 mL of solution A and add 0.01 g of sodium carboxymethyl cellulose with a viscosity of 500 mPa·s, 0.015 g of sodium alginate, and 0.005 g of sodium lauryl sulfate to obtain solution B;

[0050] Step 3: Heat the above solution B to 65° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stir for 20 minutes;

[0051] Step 4: Add 0.4 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 4.5;

[0052] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 165° C. for 10 hours to obtain a suspension;

[0053] Step 6: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 65°C for 24 hours to obtain a flaky Na 0.64 V2O5 zinc ion battery electrode material.

[0054] Example 4:

[0055] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 70°C, wherein the volume of ethylene glycol is 240 mL and the volume of water is 560 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.05 mol / L, marked as solution A;

[0056] Step 2: 80 mL of solution A was added with 0.1 g of sodium carboxymethyl cellulose having a viscosity of 600 mPa·s, 0.02 g of sodium alginate, and 0.01 g of sodium octadecyl sulfate to obtain solution B;

[0057] Step 3, heating the B solution to 70° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stirring for 17 minutes;

[0058] Step 4: Add 0.6 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 3.5;

[0059] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 170° C. for 16 hours to obtain a suspension;

[0060] Step 6: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 70°C for 24 hours to obtain a flaky Na 0.64 V2O5 zinc ion battery electrode material.

[0061] Example 5:

[0062] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 75°C, wherein the volume of ethylene glycol is 120 mL and the volume of water is 680 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.07 mol / L, marked as solution A;

[0063] Step 2: Take 80 mL of solution A and add 0.08 g of sodium carboxymethyl cellulose with a viscosity of 800 mPa·s, 0.012 g of sodium alginate, 0.007 g of sodium dodecylbenzenesulfonate and sodium octadecyl sulfate to obtain solution B;

[0064] Step 3, heating the B solution to 75° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stirring for 15 minutes;

[0065] Step 4: Add 0.8 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 5;

[0066] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 175° C. for 14 hours to obtain a suspension;

[0067] Step 6: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 75°C for 24 hours to obtain a flaky Na 0.64 V2O5 zinc ion battery electrode material.

[0068] Example 6:

[0069] Step 1: Dissolve NH4VO3 uniformly in a mixed solution of water and ethylene glycol at 80°C, wherein the volume of ethylene glycol is 200 mL and the volume of water is 600 mL, to obtain NH4 + NH4VO3 solution with a concentration of 0.08 mol / L, marked as solution A;

[0070] Step 2: Take 80 mL of solution A and add 0.02 g of sodium carboxymethyl cellulose with a viscosity of 700 mPa·s, 0.008 g of sodium alginate, and 0.015 g of sodium stearate to obtain solution B;

[0071] Step 3: heating the solution B to 80° C. in a DF-101S heat-collecting constant temperature heating magnetic stirrer and stirring for 15 minutes;

[0072] Step 4: Add 1 mol / L dilute hydrochloric acid to the solution obtained in step 3 to adjust the pH to 3.8;

[0073] Step 5: placing the solution obtained in step 4 in a reaction kettle lined with polytetrafluoroethylene, and reacting at a hydrothermal temperature of 180° C. for 6 hours to obtain a suspension;

[0074] Step 6: After the reaction is completed, the suspension is naturally cooled to room temperature, and the suspension is vacuum filtered. The suspension is washed alternately with water and ethanol to obtain a black precipitate, which is then vacuum dried at 80°C for 12 hours to obtain flaky Na 0.64 V2O5 zinc ion battery electrode material.

Claims

1. A reed-like self-assembled layered structure Na 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: The following steps are involved: Step 1, dissolve NH4VO3 uniformly in a mixed solvent of water and ethylene glycol to obtain NH4 + NH4VO3 solution with a concentration of 0.02-0.08 mol / L, marked as solution A; Step 2: Take 80 mL of solution A, add 0.01-0.1 g of sodium carboxymethyl cellulose and 0.005-0.02 g of sodium alginate to obtain solution B; Step 3, heating the B solution at 60-80° C. and stirring uniformly until the solution turns light yellow; Step 4, adjusting the pH value of the light yellow solution obtained in step 3 to 3-5; Step 5: placing the solution obtained in step 4 in a reaction kettle and reacting at a hydrothermal temperature of 160-180° C. for 6-24 hours to obtain a suspension; Step 6: After the suspension is naturally cooled to room temperature, vacuum filtration is performed, and the suspension is alternately washed with water and ethanol to obtain a black precipitate. The black precipitate is vacuum dried at 60-80° C. to obtain a reed-like self-assembled layered structure sodium vanadate zinc ion battery positive electrode material.

2. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: In the mixed solvent of step 1, the volume ratio of ethylene glycol to water is (0.5-3): (7-9.5).

3. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: The temperature of the mixed solvent in step 1 is 60-80°C.

4. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: The viscosity of the sodium carboxymethyl cellulose in step 2 is 300 to 800 mPa·s.

5. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: In step 2, 0.005 to 0.02 g of a surfactant is further added, wherein the surfactant is specifically one or more of sodium lauryl sulfate, chitosan quaternary ammonium salt, sodium dodecylbenzenesulfonate, sodium octadecyl sulfate or sodium stearate.

6. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: The heating method in step 3 is water bath heating, and the heating and stirring time is 15 to 30 minutes.

7. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: In step 4, dilute hydrochloric acid with a concentration of 0.2 to 1 mol / L is added to adjust the pH value.

8. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: In step 6, the vacuum filtration is performed using a 0.2 μm organic nylon filter membrane.

9. The reed-like self-assembled layered structure Na according to claim 1 0.64 The preparation method of V2O5 zinc ion battery positive electrode material is characterized in that: The vacuum drying in step 6 adopts an electric vacuum drying oven.

10. A Na with a reed-like self-assembled layered structure obtained by the preparation method according to any one of claims 1 to 9 0.64 V2O5 zinc ion battery positive electrode material.

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