Preparation method and application of layered double hydroxide sodium-ion battery negative electrode material

Abstract

The application provides a preparation method of a layered double hydroxide sodium ion battery negative electrode material and application thereof, and belongs to the technical field of preparation of sodium ion battery negative electrode materials. The preparation method comprises the following steps: mixing magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and seven potassium hydrogen six tantalum nineteen oxygen cluster compounds, and then wet grinding to obtain an initial solid material; and washing, ultrasonicating and vacuum drying the initial solid material to obtain the layered double hydroxide sodium ion battery negative electrode material. + The Ta6 is inserted into the Mg3Al-LDH, the effect of expanding the interlayer spacing of the Mg3Al-LDH is achieved, the embedding and de-embedding of Na+ are facilitated, the stability of the structure of the negative electrode material is improved, and the discharge specific capacity and the cycle performance of the sodium ion battery are improved.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a layered double hydroxide sodium ion battery negative electrode material and application thereof, and belongs to the technical field of preparation of a sodium ion battery negative electrode material. BACKGROUND

[0002] Nowadays, the demand for lithium ion batteries is rapidly increasing in the fields of electronic products, electric vehicles, energy storage, etc. Sodium ion batteries are attracting attention due to their similar working principle to lithium ion batteries. The abundance of sodium in the earth's crust is 2.3%, much higher than that of lithium (0.0017%). Due to the wide distribution of sodium resources and low production cost, sodium ion batteries are expected to become one of the substitutes for lithium ion batteries in the field of energy storage.

[0003] Layered double hydroxides (LDHs) are hydrotalcite-like compounds or anionic clays, which are considered as a promising energy storage material. They are usually composed of positively charged host layers formed by divalent and trivalent metal cations and interlayers formed by charge-balancing anions and water molecules. LDHs have high ion exchange performance, memory effect, adjustable internal nanostructure, high surface area, etc. However, the current products have a small interlayer spacing, resulting in low capacity of LDHs, which limits their application in the field of energy storage.

[0004] Chinese patent document with publication number CN115893526A discloses a nickel-iron-manganese layered hydroxide precursor for sodium ion batteries, a preparation method and application. The method passes a mixed metal salt solution composed of nickel salt, ferrous salt and manganese salt, a precipitating agent and a complexing agent into a reaction kettle for co-precipitation reaction. Since the preparation method uses traditional reaction heating mode, it is easy to cause the collapse of the layered structure (smaller interlayer spacing), resulting in lower capacity. In addition, inert gas needs to be continuously passed during the reaction process, which is complicated to operate.

[0005] Chinese patent document with publication number CN119446800A discloses a sulfur-doped nickel-manganese layered double hydroxide electrode material, a preparation method and a capacitor. The method uses one-step hydrothermal method to grow sulfur-doped nickel-manganese layered double hydroxide on foamed nickel, with a reaction time of 10-16h and a reaction temperature of 100-180℃. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a layered double hydroxide sodium ion battery negative electrode material and application thereof, which has a short reaction time, low reaction temperature, large interlayer spacing and high capacity of the prepared layered double hydroxide sodium ion battery negative electrode material.

[0007] To achieve this purpose, the technical solution of the present application is as follows:

[0008] In one aspect, the application provides a preparation method of a layered double hydroxide sodium-ion battery negative electrode material, comprising the following steps:

[0009] The magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and K7HTa6O

[0010] Further, the molar ratio of the magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and K7HTa6O

[0011] Further, the wet grinding conditions are as follows: the zirconium oxide balls with a diameter of 10 mm are used, the ball-to-material mass ratio is 8-10:1, the wet grinding speed is 200-300 r / min, the wet grinding time is 20 min-1 h, deionized water is used as the initiator, and the molar ratio of the deionized water to the aluminum nitrate nonahydrate is 12-18:1.

[0012] Further, deionized water is used as the washing agent, the mass ratio of the deionized water to the initial solid material is 3-5:1, and the ultrasonic time is 30 min-1 h.

[0013] Further, the vacuum drying temperature is 40-60 DEG C, and the vacuum drying time is 10-24 h.

[0014] In another aspect, the application provides an application of the layered double hydroxide sodium-ion battery negative electrode material prepared by the above method, which is applied to a sodium-ion battery negative electrode.

[0015] The application has the following advantages:

[0016] The layered double hydroxide Mg3Al-LDH-Ta6 negative electrode material is prepared by the wet grinding method, compared with the LDH materials prepared by the hydrothermal method and the precipitation method, the preparation method can be completed by one-step wet grinding, the material particles can be dispersed more uniformly by adding an appropriate amount of deionized water as an initiator for wet grinding, the refining effect is increased, and the formation of the layered structure and the pores is facilitated.

[0017] The magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and K7HTa6O 19 The K7HTa6O 19The metal cluster of 13H2O is composed of six Ta and 19 O. Since the diameter of Ta6 is usually above 1 nm, the introduction of Ta6 anion can achieve the effect of expanding the interlayer spacing, and the Coulomb force is weaker than that of pure layered double hydroxide, which is beneficial to the embedding / de-embedding reaction of Na + . Meanwhile, the interlayer spacing is increased, the contact surface area between layers is increased, the specific surface area of the material is improved, a large number of pore structures are formed in the material, and the rich void structure provides more active sites for electrochemical reaction, thereby improving the discharge specific capacity of the sodium ion battery. On the other hand, since Ta6 is a metal cluster structure formed by multiple metals, the addition of Ta6 can not only improve the electrical activity of metal ions, but also support the layered skeleton, improve the structural stability of the layered double hydroxide, and further improve the cycle performance of the sodium ion battery.

[0018] The prepared layered double hydroxide Mg3Al-LDH-Ta6 sodium ion battery negative material has a discharge specific capacity of 335.85-358.50 mAhg -1 under a current density of 0.5 Ag -1 , and a capacity retention rate of 85.6-93.7% after 300 cycles without obvious attenuation, which provides a possibility for preparing a sodium ion battery with high cycle life. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The infrared spectrum of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure;

[0020] Figure 2 The X-ray powder diffraction pattern of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure;

[0021] Figure 3 The scanning electron microscope image of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure;

[0022] Figure 4 The cycle performance graph of the layered double hydroxide sodium ion battery negative material of Example 1 under a current density of 0.5 Ag -1 . DETAILED DESCRIPTION

[0023] The present application will be further described below in combination with the drawings and specific examples, so that those skilled in the art can better understand the implementation of the present application, but the protection scope of the present application is not limited thereto. K7HTa6O 19 13H2O (thirteen water seven potassium hydrogen six tantalum nineteen oxygen cluster compound) can be purchased on the market, of course, in the following various embodiments, K7HTa6O 19• 13H2O was made in the lab. The preparation method was as follows: 0.05 mol Ta2O5 and 0.46 mol KOH were mixed and then added to a nickel crucible. The mixture was heated in a tube furnace (under N2 atmosphere) at 380 °C for 30 min, and then the reacted mixture was slowly cooled to room temperature and poured into 100 mL of deionized boiling water. The above mixture was filtered, and the filtrate was placed in a 0 °C refrigerator for 12 h to obtain needle-like solids, which were collected and washed with ethanol-water (ethanol to water in a volume ratio of 1:1) five times. Finally, the above solids were dried at 40 °C under vacuum for 24 h to obtain K7HTa6O 19 • 13H2O solid. Example 1

[0024] (1) 5.6 g of magnesium nitrate hexahydrate, 3.5 g of aluminum nitrate nonahydrate, 5 g of sodium hydroxide, and 3 g of K7HTa6O 19 • 13H2O (thirteen-potassium hydrogen six-potassium nineteen- oxygen cluster compound) were respectively put into 25 mL stainless steel grinding pots;

[0025] (2) The starting material powder was wet-milled for 30 min at a rotation speed of 250 r / min using zirconia balls with a diameter of 10 mm and a ball-to-material mass ratio of 8:1, and 0.13 mol of deionized water as an initiator to obtain the initial solid material;

[0026] (3) The initial solid material was washed with 97 g of deionized water and ultrasonically treated for 30 min;

[0027] (4) The above product was dried at a temperature of 40 °C and a vacuum degree of -0.1 MPa for 24 h to obtain a layered double hydroxide sodium-ion battery negative electrode material; named Mg3Al-LDH-Ta6-1. Example 2

[0028] (1) 4.62 g of magnesium nitrate hexahydrate, 3.5 g of aluminum nitrate nonahydrate, 4 g of sodium hydroxide, and 4 g of K7HTa6O 19 • 13H2O were respectively put into 25 mL stainless steel grinding pots;

[0029] (2) The starting material powder was wet-milled for 1 h at a rotation speed of 300 r / min using zirconia balls with a diameter of 10 mm and a ball-to-material mass ratio of 9:1, and 0.11 mol of deionized water as an initiator to obtain the initial solid material;

[0030] (3) The initial solid material was washed with 73 g of deionized water and ultrasonically treated for 1 h;

[0031] (4) The above product is dried under the conditions of a temperature of 50°C and a vacuum degree of -0.1 MPa for 20 h to obtain a layered double hydroxide sodium-ion battery negative electrode material; named as Mg3Al-LDH-Ta6-2. Example 3

[0032] (1) 5.13 g of magnesium nitrate hexahydrate, 3.5 g of aluminum nitrate nonahydrate, 3 g of sodium hydroxide, and 2 g of K7HTa6O 19 ·13H2O are respectively put into 25 mL stainless steel grinding pots;

[0033] (2) Zirconium oxide balls with a diameter of 10 mm are used, the ball-to-material mass ratio is 10:1, 0.15 mol of deionized water is used as an initiator, and the starting material powder is wet-milled at a speed of 200 r / min for 40 min to obtain an initial solid material;

[0034] (3) The initial solid material is washed with 49 g of deionized water and ultrasonically treated for 40 min;

[0035] (4) The above product is dried under the conditions of a temperature of 60°C and a vacuum degree of -0.1 MPa for 10 h to obtain a layered double hydroxide sodium-ion battery negative electrode material; named as Mg3Al-LDH-Ta6-3. Example 4

[0036] (1) 5.90 g of magnesium nitrate hexahydrate, 3.5 g of aluminum nitrate nonahydrate, 4 g of sodium hydroxide, and 3 g of K7HTa6O 19 ·13H2O are respectively put into 25 mL stainless steel grinding pots;

[0037] (2) Zirconium oxide balls with a diameter of 10 mm are used, the ball-to-material mass ratio is 9:1, 0.17 mol of deionized water is used as an initiator, and the starting material powder is wet-milled at a speed of 200 r / min for 20 min to obtain an initial solid material;

[0038] (3) The initial solid material is washed with 97 g of deionized water and ultrasonically treated for 50 min;

[0039] (4) The above product is dried under the conditions of a temperature of 40°C and a vacuum degree of -0.1 MPa for 15 h to obtain a layered double hydroxide sodium-ion battery negative electrode material; named as Mg3Al-LDH-Ta6-4. Comparative Example 1

[0040] The difference between Comparative Example 1 and Example 1 is that the amount of K7HTa6O 19 ·13H2O in step (1) is 0.8 g, and the others are unchanged. Comparative Example 2

[0041] Comparative Example 2 differs from Example 1 in that the zirconium oxide ball diameter in step (2) is 50 mm, and the rest is the same. Comparative Example 3

[0042] Comparative Example 3 differs from Example 1 in that ethanol is used as an initiator in step (2), and the rest is the same. Comparative Example 4

[0043] Comparative Example 4 differs from Example 1 in that the amount of deionized water in step (2) is 0.4 mol, and the rest is the same.

[0044] Application Example 1

[0045] The layered double hydroxide sodium ion battery negative electrode material obtained in Examples 1-4 and Comparative Examples 1-4 is used as the sodium ion battery negative electrode, a glass fiber membrane (Whatman GF / D) is used as the separator, a sodium sheet is used as the counter electrode, and an electrolyte (1M NaPF6+EC / DEC+5% FEC) is used to assemble a button cell in a glove box filled with an inert atmosphere. The battery is tested for electrochemical cycle performance on a CT3002A system at a test voltage of 0.01-3.0V, and the test results are shown in Table 1.

[0046] Table 1 Electrochemical cycle performance test results of Examples 1-4 and Comparative Examples 1-4 at a current density of 0.5 Ag -1

[0047]

[0048] As can be seen from Table 1 and Figure 4 , the first discharge specific capacity of Example 1 at a current density of 0.5 Ag -1 is 358.50 mAhg -1 , and after 300 cycles, the capacity is maintained at 335.91 mAhg -1 , the average cycle capacity decay rate is 0.021%, the capacity retention rate is 93.7%, and it has good initial specific capacity, cycle stability and low capacity decay rate. Compared with Example 1, Comparative Example 1 exhibits poor cycle stability and higher capacity decay rate under the same conditions. The main reason for this performance advantage is that after adding an appropriate amount of Ta6, Ta6 as an interlayer anion can expand the interlayer space of Mg3Al-LDH, promoting the diffusion of Na + ​The insertion and de-insertion of Ta6, while increasing the specific surface area of the material, forms a large number of pore structures inside the material, the rich pore structure provides more active sites for electrochemical reaction, more ions can react on the electrode surface, and the initial specific discharge capacity is improved. On the other hand, the stability of the material is improved, and the cycle performance is improved. In Comparative Example 1, due to the reduction of the amount of Ta6, the material layer spacing changes little, and the void is small, the layered structure is unstable, and thus the electrochemical performance is reduced. As can be seen from Example 1 and Comparative Example 2, when the diameter of the zirconium oxide ball increases, the wet grinding degree is not sufficient, Ta6 cannot be well inserted into the layered double hydroxide, and the performance is reduced. As can be seen from Example 1 and Comparative Example 3, when ethanol is used as an initiator, because the polarity of ethanol is lower than that of water, the raw materials cannot be effectively combined to form a layered structure and the layer spacing is small, and thus the performance is reduced. As can be seen from Example 1 and Comparative Example 4, when the amount of deionized water is too much during wet grinding, the viscosity of the raw materials is reduced, the collision energy between the grinding balls and the raw materials is weakened, the mechanical force transmission efficiency is reduced, the refinement effect is reduced, and the layered material cannot be well formed. At the same time, too much deionized water will also dilute the concentration of the raw materials, affect the surface charge distribution and particle stability of the materials, and reduce the electrochemical performance.

[0049] Figure 1 The infrared spectrum of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure. As can be seen from the figure, the Mg3Al-LDH-Ta6 has an absorption peak at 500-1000 cm -1 of the absorption peak of Ta6 cluster, indicating that the guest anion Ta6 oxygen cluster has been successfully inserted into the LDH.

[0050] Figure 2 The X-ray powder diffraction pattern of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure. As can be seen from the figure, the (003) diffraction peak of Mg3Al-LDH-Ta6 is split into two peaks, one peak moves to the lower angle region of 9.9°, which retains the characteristic peak of hydrotalcite and the characteristic peak of Ta6 oxygen cluster, which strongly proves that Ta6 cluster has been inserted into the LDH layer, which is consistent with the FT-IR analysis result.

[0051] Figure 3 The scanning electron microscope image of the layered double hydroxide sodium ion battery negative material of Example 1 is shown in the figure. The typical nanosheet morphology of LDH is shown.

[0052] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a layered double hydroxide sodium-ion battery anode material, characterized in that, The method comprises the following steps: mixing magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and seven potassium hydrogen six tantalum nineteen oxygen cluster hydrate thirteen hydrate, and wet grinding to obtain an initial solid material; and washing, ultrasonicating and vacuum drying the initial solid material to obtain a layered double hydroxide sodium-ion battery negative electrode material. The molar ratio of the magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide, and seven potassium hydrogen six tantalum nineteen oxygen cluster of thirteen hydrates is 1.9-2.5:1:8-13.5:0.11-0.23; the chemical formula of the seven potassium hydrogen six tantalum nineteen oxygen cluster of thirteen hydrates is K7HTa6O 19 • 13H2O; The wet grinding conditions are as follows: the zirconium oxide ball has a diameter of 10 mm, the ball-to-material mass ratio is 8-10:1, the wet grinding speed is 200-300 r / min, the wet grinding time is 20 min-1 h, deionized water is used as an initiator, and the molar ratio of deionized water to aluminum nitrate nonahydrate is 12-18:

1.

2. The method for preparing the layered double hydroxide sodium-ion battery anode material according to claim 1, characterized in that, Deionized water is used as a washing agent, the mass ratio of deionized water to the initial solid material is 3-5:1, and the ultrasonicating time is 30 min-1 h.

3. The method for preparing the layered double hydroxide sodium-ion battery anode material according to claim 1, characterized in that, The vacuum drying temperature is 40-60 DEG C, and the vacuum drying time is 10-24 h.

4. Use of a layered double hydroxide sodium-ion battery anode material prepared according to the method of any one of claims 1 to 3, characterized in that, The layered double hydroxide sodium-ion battery negative electrode material is applied to a sodium-ion battery negative electrode.

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