Electrode material, preparation method therefor and use thereof

Abstract

The application discloses an electrode material and a preparation method and application thereof in a lithium ion battery electrode material, and belongs to the field of lithium ion batteries. The electrode material is copper melloate doped with hydroxyl copper fluoride; the preparation method of the material comprises the following steps: (1) preparing hydroxyl copper fluoride powder; (2) preparing copper melloate doped with hydroxyl copper fluoride. The material provided by the application can be used in a lithium ion battery as a negative electrode material. Due to the doping of metal fluoride, a more stable SEI film can be formed on the electrode surface, so that the material exhibits good cycle stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the preparation and application of a lithium ion battery electrode material, in particular to an electrode material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, new energy technology is more and more widely used, among which the most mature lithium ion battery develops rapidly and occupies a large proportion in actual production and life. However, with the increasing complexity of market demand for new energy technology, the further development of lithium ion battery also faces severe challenges. One of the challenges is to develop an ideal negative electrode material with high capacity, safety performance and long life stability. Metal organic framework (MOF) has high specific capacity and is considered to be one of the most promising materials to replace graphite negative electrode. However, compared with carbon materials, the cycle stability of metal organic framework materials is usually poor.

[0003] The SEI film formed on the surface of the negative electrode material can improve the cycle stability of the lithium ion battery. Adding various additives to promote the formation of SEI film in electrolyte is a common means to improve the stability of lithium battery. LiF is one of the effective components in SEI film, and increasing the content of LiF in SEI film can significantly improve the cycle stability of lithium ion secondary battery. However, the fluorinated additives used in electrolyte are usually high in price, which is not conducive to large-scale production and application. SUMMARY

[0004] The present application aims to provide a hydroxyl copper fluoride doped copper mellitate electrode material with good cycle stability; another object of the present application is to provide a preparation method of the material, which replaces the addition of fluorine-containing additives in electrolyte by directly adding hydroxyl copper fluoride, thereby reducing the production cost; another object of the present application is to provide the application of the material as an electrode in lithium ion battery.

[0005] Technical scheme: the electrode material provided by the present application is copper mellitate doped with hydroxyl copper fluoride. It is prepared by the following two steps:

[0006] (1) preparing hydroxyl copper fluoride;

[0007] (2) ball milling to prepare hydroxyl copper fluoride doped copper mellitate.

[0008] Further, the step (1) comprises the following steps:

[0009] (11) heating and dissolving ammonium fluoride and copper nitrate in diethylene glycol respectively;

[0010] (12) slowly adding the above-mentioned copper nitrate solution to the ammonium fluoride solution and heating, stirring until a light green precipitate is produced;

[0011] (13) The hydroxyl copper fluoride powder is obtained by drying the precipitate after centrifugal washing with anhydrous ethanol.

[0012] Further, in step (11), the concentration of ammonium fluoride is 0.25-0.32 mol / L, the heating temperature is 50-100 ℃, the concentration of copper nitrate is 0.5-0.8 mol / L, the heating temperature is 50-100 ℃, and the molar ratio of ammonium fluoride to copper nitrate is 2-2.5:1; in step (12), the heating temperature is 100-150 ℃, and heating is performed until a green precipitate is produced; in step (13), the drying condition is vacuum drying, the drying temperature is 100-150 ℃, and the drying time is 8-12 h.

[0013] Further, step (2) comprises the following steps:

[0014] (21) At room temperature, resorcinol and copper acetate monohydrate are weighed into a ball mill jar, anhydrous ethanol is added, and the ball mill jar is placed on a ball mill for ball milling;

[0015] (22) Hydroxyl copper fluoride is added to the ball mill jar for ball milling, and drying.

[0016] Further, in step (21), the molar ratio of copper acetate monohydrate to resorcinol is 3:2, the ball milling time is 30-40 min, and the rotation speed is 500-600 rpm; in step (22), the mass of the hydroxyl copper fluoride is 5-15% of the total mass of the copper acetate monohydrate and resorcinol, the ball milling time is 3-5 min, the drying temperature is 100-150 ℃, and the drying time is 8-12 h. The electrode material can be applied to a lithium ion battery.

[0017] Advantages: Compared with the prior art, the present application has the following significant advantages: (1) low production cost, the present application directly adds hydroxyl copper fluoride to the electrode material instead of adding a fluorine-containing additive to the electrolyte to improve the cycle performance of the battery, the raw material hydroxyl copper fluoride is cheap and the amount used is small, which is more economical and practical compared with the relatively expensive fluorine-containing electrolyte additive; (2) good cycle stability of the electrode material, the hydroxyl copper fluoride contained in the copper resorcinolate can react with lithium ions during charging and discharging to form lithium fluoride, and lithium fluoride is one of the main components of the SEI film, so that the material can form a more stable SEI film during charging and discharging, thereby improving the cycle stability of the electrode and enabling the material to be applied to a lithium ion battery. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a scanning electron microscope image of the product of Example 2;

[0019] Figure 2 is an X-ray powder diffraction pattern of the products of Example 2 and the comparative example.

[0020] Figure 3 is a lithium cycling performance chart of the product of Example 2 and the comparative product. DETAILED DESCRIPTION

[0021] The technical solutions of the present application are further described below in conjunction with the drawings.

[0022] Example 1

[0023] The hydroxy copper fluoride doped copper mellenate electrode material, the hydroxy copper fluoride accounts for 5% of the total mass of copper acetate monohydrate and mellenate raw materials, and the preparation method is as follows:

[0024] 0.46 g (12.5 mmol) of ammonium fluoride was poured into 50 mL of diethylene glycol and heated to 50 °C to dissolve it. Then 1.21 g (5 mmol) of copper nitrate trihydrate was dissolved in 10 mL of diethylene glycol and heated to 50 °C to dissolve it into a transparent solution. At 50 °C, the solution was injected into the former solution and stirred, and the temperature was quickly raised to 100 °C during stirring and kept until a green precipitate was produced, and then naturally cooled to room temperature. The solid particles were collected by centrifugation, and then the solid particles were washed with ethanol and placed in a vacuum drying oven at 100 °C for 8 h to obtain hydroxy copper fluoride.

[0025] 1 g (5 mmol) of copper acetate monohydrate, 0.69 g (3.3 mmol) of mellenate and 1 mL of ethanol were weighed into a ball mill jar and ground at a speed of 500 rpm for 30 min. Then the ball mill jar was opened and 0.085 g (5%) of hydroxy copper fluoride powder was poured in and ball milled for another 3 min. The product was collected and then washed with ethanol three times by ultrasonic. Finally, the product was dried in a vacuum drying oven at 100 °C for 8 h to obtain the product of Example 1.

[0026] Example 2

[0027] The hydroxy copper fluoride doped copper mellenate electrode material, the hydroxy copper fluoride accounts for 5% of the total mass of copper acetate monohydrate and mellenate raw materials, and the preparation method is as follows:

[0028] Into 50 mL of diglycol was added 0.592 g (16 mmol) of ammonium fluoride and heated to 100 °C to dissolve. Separately, 1.93 g (8 mmol) of copper nitrate trihydrate was dissolved in 10 mL of diglycol and heated to 80 °C to make a clear solution. At 80 °C, this solution was injected into the former solution and stirred, the temperature was quickly raised to 120 °C while stirring and maintained until green precipitate was produced, allowed to cool to room temperature naturally. The solid particles were collected by centrifugation, then the solid particles were washed with ethanol, and put into a vacuum drying oven at 150 °C for 12 h to get hydroxyl copper fluoride.

[0029] Into a ball mill jar was placed 1.2 g (6 mmol) of copper acetate monohydrate, 0.84 g (4 mmol) of trimesic acid, and 1 mL of ethanol and milled at 600 rpm for 40 min. The ball mill jar was then opened and 0.102 g (5%) of hydroxyl copper fluoride powder was added and milled for another 5 min. The product was collected and then washed with ethanol by sonication three times. Finally, the product was dried in a vacuum drying oven at 150 °C for 12 h to get the product of Example 2.

[0030] Example 3

[0031] The hydroxyl copper fluoride doped copper trimesate electrode material, with hydroxyl copper fluoride being 10% of the total mass of copper acetate monohydrate and trimesic acid feed, was prepared as follows:

[0032] Into 50 mL of diglycol was added 0.592 g (16 mmol) of ammonium fluoride and heated to 100 °C to dissolve. Separately, 1.93 g (8 mmol) of copper nitrate trihydrate was dissolved in 10 mL of diglycol and heated to 80 °C to make a clear solution. At 80 °C, this solution was injected into the former solution and stirred, the temperature was quickly raised to 120 °C while stirring and maintained until green precipitate was produced, allowed to cool to room temperature naturally. The solid particles were collected by centrifugation, then the solid particles were washed with ethanol, and put into a vacuum drying oven at 150 °C for 12 h to get hydroxyl copper fluoride.

[0033] Into a ball mill jar was placed 1.4 g (7 mmol) of copper acetate monohydrate, 0.99 g (4.7 mmol) of trimesic acid, and 1 mL of ethanol and milled at 500 rpm for 40 min. The ball mill jar was then opened and 0.24 g (10%) of hydroxyl copper fluoride powder was added and milled for another 3 min. The product was collected and then washed with ethanol by sonication three times. Finally, the product was dried in a vacuum drying oven at 120 °C for 10 h to get the product of Example 3.

[0034] Example 4

[0035] The hydroxy copper fluoride doped copper molybdate electrode material, hydroxy copper fluoride is 10% of the total mass of copper acetate monohydrate and molybdic acid feedstock, is prepared as follows:

[0036] Pour 0.56 g (15 mmol) of ammonium fluoride into 50 mL of diethylene glycol and heat to 80 °C to dissolve. Dissolve 1.7 g (7 mmol) of copper nitrate trihydrate in another 10 mL of diethylene glycol and heat to 60 °C to make a clear solution. At 80 °C, inject this solution into the former solution and stir, quickly raising the temperature to 130 °C while stirring and hold until a green precipitate is produced, cool to room temperature naturally. Collect the solid particles by centrifugation, then wash the solid particles with ethanol, and place in a vacuum drying oven at 110 °C for 10 h to obtain hydroxy copper fluoride.

[0037] Weigh 1.6 g (8 mmol) of copper acetate monohydrate, 1.1 g (5.3 mmol) of molybdic acid, and 1 mL of ethanol into a ball mill jar and mill at 600 rpm for 30 min. Then open the ball mill jar and pour in 0.27 g (10%) of hydroxy copper fluoride powder and mill for another 4 min. Collect the product, then ultrasonically wash the product in ethanol three times. Finally, dry the product in a vacuum drying oven at 130 °C for 9 h to obtain the product of Example 4.

[0038] Example 5

[0039] The hydroxy copper fluoride doped copper molybdate electrode material, hydroxy copper fluoride is 15% of the total mass of copper acetate monohydrate and molybdic acid feedstock, is prepared as follows:

[0040] Pour 0.63 g (17 mmol) of ammonium fluoride into 50 mL of diethylene glycol and heat to 100 °C to dissolve. Dissolve 1.93 g (8 mmol) of copper nitrate trihydrate in another 10 mL of diethylene glycol and heat to 50 °C to make a clear solution. At 100 °C, inject this solution into the former solution and stir, quickly raising the temperature to 120 °C while stirring and hold until a green precipitate is produced, cool to room temperature naturally. Collect the solid particles by centrifugation, then wash the solid particles with ethanol, and place in a vacuum drying oven at 150 °C for 8 h to obtain hydroxy copper fluoride.

[0041] Weigh 1.2 g (6 mmol) of copper acetate monohydrate, 0.84 g (4 mmol) of trimellitic acid, and 1 mL of ethanol into a ball mill jar and grind at 550 rpm for 35 min. Then, open the ball mill jar, pour in 0.306 g (15%) of copper hydroxyfluoride powder, and ball mill for another 3 min. Collect the product and then ultrasonically wash it three times in ethanol. Finally, dry the product in a vacuum drying oven at 100 °C for 8 h to obtain the product of Example 5.

[0042] Example 6

[0043] The copper hydroxyfluoride-doped copper pyromellitic acid electrode material, wherein the copper hydroxyfluoride accounts for 15% of the total mass of copper acetate monohydrate and pyromellitic acid, is prepared as follows:

[0044] 0.46 g (12.5 mmol) of ammonium fluoride was dissolved in 50 mL of diethylene glycol and heated to 50 °C. Separately, 1.21 g (5 mmol) of copper nitrate trihydrate was dissolved in 10 mL of diethylene glycol and heated to 100 °C to form a clear solution. This solution was injected into the first solution at 50 °C with stirring. While stirring, the temperature was rapidly increased to 100 °C and maintained until a green precipitate formed. The solution was then allowed to cool naturally to room temperature. The solid particles were collected by centrifugation, washed with ethanol, and dried in a vacuum oven at 130 °C for 12 h to obtain copper hydroxyfluoride.

[0045] Weigh 1.4 g (7 mmol) of copper acetate monohydrate, 0.99 g (4.7 mmol) of trimellitic acid, and 1 mL of ethanol into a ball mill jar and grind at 550 rpm for 35 min. Then, open the ball mill jar, add 0.36 g (15%) of copper hydroxyfluoride powder, and ball mill for another 5 min. Collect the product and then ultrasonically wash it three times in ethanol. Finally, dry the product in a vacuum drying oven at 140 °C for 12 h to obtain the product of Example 6.

[0046] Comparative Example

[0047] Weigh 1.2 g (6 mmol) of copper acetate monohydrate, 0.8 g (4 mmol) of trimellitic acid, and 1 mL of ethanol and place them in a ball mill jar. Grind the mixture at 600 rpm for 40 min. Collect the product, then ultrasonically wash it three times in ethanol. Finally, dry the product in a vacuum drying oven at 150 °C for 12 h to obtain the comparative product.

[0048] Application Examples

[0049] like Figure 1 As shown, the microstructure of the copper hydroxyfluoride-doped copper pyromellitic acid obtained in Example 2 consists of micron-sized irregular particles.Figure 2 X-ray powder diffraction patterns of the products of Example 2 and the comparative example, from which it can be seen that Example 2 and the comparative example have diffraction peaks at 9.64, 11.69, 13.48, 19.08, 26.18 and 29.45 °, corresponding to the copper resorcinol phase, indicating that adding a small amount of hydroxyl copper fluoride to copper resorcinol does not affect the phase structure of copper resorcinol. Figure 3 Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1 The Li cycling performance of Example 2 and the comparative example at a current density of 100 mA g -1 -1 -1

Claims

1. An electrode material, characterized by, The electrode material is copper hydroxy fluoride doped in copper trimesate; the electrode material is applied in lithium ion battery, and the copper hydroxy fluoride reacts with lithium ion to form lithium fluoride during the charging and discharging process of the battery. The preparation method of the electrode material comprises the following steps: (1) preparing copper hydroxy fluoride; (2) preparing copper hydroxy fluoride doped copper trimesate; The step (1) comprises the following steps: (11) adding ammonium fluoride and copper nitrate into diethylene glycol respectively and heating to dissolve; (12) slowly injecting the above-mentioned copper nitrate solution into the ammonium fluoride solution and heating, stirring until a light green precipitate is generated; (13) centrifugally washing the above-mentioned precipitate with anhydrous ethanol and drying to obtain copper hydroxy fluoride powder; The step (2) comprises the following steps: (21) weighing copper trimesate and copper acetate monohydrate at room temperature, adding anhydrous ethanol into a ball mill jar, and placing the ball mill jar on a ball mill for ball milling; the molar ratio of the copper acetate monohydrate and the copper trimesate is 3:2; (22) adding copper hydroxy fluoride into the ball mill jar and ball milling again, and drying; the mass of the copper hydroxy fluoride is 5-15% of the total mass of the raw materials.

2. The method of claim 1, wherein the method further comprises: In the step (11), the concentration of the ammonium fluoride is 0.25-0.32 mol / L, and the heating temperature is 50-100 ℃; the concentration of the copper nitrate is 0.5-0.8 mol / L, and the heating temperature is 50-100 ℃; the molar ratio of the ammonium fluoride and the copper nitrate is 2-2.5:

1.

3. The method of claim 1, wherein the method further comprises: In the step (12), the heating temperature is 100-150 ℃, and the heating is performed until a green precipitate is generated.

4. The method of claim 1, wherein the method further comprises: In the step (13), the drying condition is vacuum drying, the drying temperature is 100-150 ℃, and the drying time is 8-12 h.

5. The method of claim 1, wherein the electrode material is prepared by a process comprising: In the step (21), the ball milling time is 30-40 min, and the rotating speed is 500-600 rpm.

6. The method of claim 1, wherein the electrode material is prepared by a method comprising: In the step (22), the ball milling time is 3-5 min, the drying temperature is 100-150 ℃, and the drying time is 8-12 h.

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