Preparation method of manganese cobalt oxide nitride negative electrode material, product and application

Abstract

The invention discloses a preparation method of a manganese cobalt oxide nitride negative electrode material as well as a product and application thereof. Manganese salt and oxalic acid are dissolved in distilled water as A; cobalt salt and oxalic acid are dispersed in the organic solvent as B; slowly dropwise adding A into B to form C; adding ammonium fluoride into C, stirring to form a transparent solution, transferring the transparent solution into a Teflon lining high-pressure sterilizer, heating, washing, filtering, and carrying out vacuum drying to obtain a manganese cobaltate precursor; calcining the manganese cobaltate precursor to obtain manganese cobaltate; and heating the manganese cobalt oxide in an Ar / NH3 mixed atmosphere to obtain the nitrided manganese cobalt oxide. When the manganese cobalt oxide nitride is used as the lithium battery negative electrode material, under the condition of 500 mA / g current density, the first discharge specific capacity is 1560 mAh / g, the third discharge specific capacity is 889 mAh / g to the 50th discharge specific capacity is 822 mAh / g, and compared with the third discharge specific capacity, the capacity retention ratio is 92.5%.

Description

Technical Field

[0001] The present invention relates to a method for preparing a negative electrode material for a lithium battery, and in particular to a method for preparing a negative electrode material of manganese cobalt nitride oxide, and a product and application thereof. Background Art

[0002] With the development of society, lithium-ion batteries have attracted much attention. Lithium-ion batteries are currently the most ideal rechargeable batteries in the world. They not only have the advantages of high energy density, long cycle life, no memory effect and low pollution, but also have the advantages of high energy density, long cycle life, no memory effect and low pollution. With the advancement of technology, lithium-ion batteries will be widely used in electric vehicles, aerospace, biomedicine and other fields. Therefore, the research and development of power lithium-ion batteries and related materials is of great significance. For power lithium-ion batteries, the key is to improve power density and energy density, and the fundamental to improve power density and energy density is the improvement of electrode materials, especially negative electrode materials.

[0003] Since the early 1990s, Japanese scientists have developed layered carbon materials. Carbon materials are the earliest materials studied and applied to the commercialization of lithium-ion batteries. They are still one of the focuses of attention and research. However, carbon negative electrode materials have some defects: when the battery is formed, it reacts with the electrolyte to form an SEI film, resulting in electrolyte consumption and low initial coulombic efficiency; when the battery is overcharged, metallic lithium may precipitate on the surface of the carbon electrode to form lithium dendrites, causing a short circuit, resulting in temperature rise and battery explosion; in addition, the diffusion coefficient of lithium ions in carbon materials is small, resulting in the battery being unable to achieve large current charging and discharging, thereby limiting the application range of lithium-ion batteries.

[0004] Mn2CoO4 is a spinel structured composite oxide, a widely used magnetic material, commonly used as a fuel cell material, and currently also used as a negative electrode material for lithium-ion batteries, with a high Li+ storage capacity through conversion and alloying reactions. This material is considered to be a promising lithium-ion negative electrode material.

[0005] The present invention provides a method for preparing a nitrided cobalt manganese oxide negative electrode material, wherein the nitrided cobalt manganese oxide negative electrode material is prepared by nitridation using a chemical solution method and an argon / ammonia mixed atmosphere, wherein the nitridation treatment improves the conductivity of the cobalt manganese oxide and further improves the electrochemical performance of the material. The preparation process is relatively simple and easy to operate. Summary of the invention

[0006] In order to overcome the shortcomings of the existing manganese cobalt oxide that the electrochemical performance is not high enough, the purpose of the present invention is to provide a method for preparing a nitride manganese cobalt oxide negative electrode material.

[0007] Another object of the present invention is to provide a manganese cobalt oxide nitride negative electrode material product obtained by the above method.

[0008] Another object of the present invention is to provide an application of the above product.

[0009] The object of the present invention is achieved by the following scheme: A method for preparing a manganese cobalt oxide nitride negative electrode material, characterized in that the manganese cobalt oxide nitride negative electrode material is prepared by nitridation using a chemical solution method and an argon / ammonia mixed atmosphere, and the specific steps of the method are: (1) Dissolve 4 mmol of soluble manganese salt and 16 mmol of oxalic acid in 50 mL of distilled water and label it as solution A.

[0010] (2) Disperse 2 mmol of soluble cobalt salt and 6 mmol of oxalic acid in 20 mL of organic solvent, labeled as solution B. Slowly add solution A dropwise into solution B to form solution C.

[0011] (3) Add 12 mmol of ammonium fluoride to solution C and stir for 100-150 min to form a transparent solution. Then, transfer solution C to a 100 mL Teflon-lined autoclave, heat at 160°-180°C for 12-18 h, wash with ethanol 3-5 times, filter, and dry in a vacuum oven at 60°-80°C for 10-20 h to obtain a manganese cobalt oxide precursor.

[0012] (4) Heat the manganese cobalt oxide precursor in a tube furnace at 600-750°C, 2-5°C min -1 The mixture is calcined at a heating rate of 4 to 8 h to obtain manganese cobaltate.

[0013] (5) Heating manganese cobalt oxide in an Ar / NH3 mixed atmosphere at 700-750°C for 1-1.5 h to obtain manganese cobalt oxide nitride.

[0014] Preferably, in step (1), the manganese salt is one or a combination of manganese acetate, manganese nitrate or manganese chloride.

[0015] Preferably, in step (2), the cobalt salt is one or a combination of cobalt acetate, cobalt nitrate or cobalt chloride.

[0016] Preferably, in step (2), the organic solvent is one or a combination of ethanol, methanol or propanol.

[0017] The present invention provides a manganese cobalt oxide nitride negative electrode material, which is prepared according to any of the above methods.

[0018] The present invention provides an application of a manganese cobalt oxide nitride negative electrode material in a lithium battery negative electrode material.

[0019] The present invention provides a method for preparing a nitrided cobalt manganese oxide negative electrode material, wherein the nitrided cobalt manganese oxide negative electrode material is prepared by nitridation using a chemical solution method and an argon / ammonia mixed atmosphere, wherein the nitridation treatment improves the conductivity of the cobalt manganese oxide and further improves the electrochemical performance of the material. The preparation process is relatively simple and easy to operate.

[0020] Under the current density of 500 mA / g, the first discharge capacity is 1560 mAh / g, the third discharge capacity is 889 mAh / g and the 50th discharge capacity is 822 mAh / g. Compared with the third discharge capacity, the capacity retention rate is 92.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cycle life diagram of manganese cobalt oxide nitride in Example 1. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1 A manganese cobalt oxide nitride negative electrode material is prepared by nitridation using a chemical solution method and an argon / ammonia mixed atmosphere, and is prepared according to the following steps: (1) Dissolve 4 mmol of soluble manganese acetate and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt acetate and 6 mmol of oxalic acid in 20 mL of organic solvent ethanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 100 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 160 °C for 18 h, wash with ethanol three times, filter, and dry in a vacuum oven at 80 °C for 10 h to obtain a manganese cobalt oxide precursor. (4) Place the cobalt oxide precursor in a tube furnace at a heating rate of 2~5℃min -1 , calcined at 600℃ for 8 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 700 °C for 1.5 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

[0024] Figure 1This is the cycle life graph of manganese cobalt oxide nitride. Under the current density of 500 mA / g, the first discharge capacity is 1560 mAh / g, the third discharge capacity is 889 mAh / g and the 50th discharge capacity is 822 mAh / g. Compared with the third discharge capacity, the capacity retention rate is 92.5%.

[0025] Example 2 A manganese cobalt oxide nitride negative electrode material is prepared similarly to Example 1 by the following steps: (1) Dissolve 4 mmol of soluble manganese nitrate and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt nitrate and 6 mmol of oxalic acid in 20 mL of organic solvent methanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 120 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 180 °C for 12 h, wash with ethanol three times, filter, and dry in a vacuum oven at 60 °C for 20 h to obtain a manganese cobalt oxide precursor. (4) The cobalt manganese oxide precursor was heated in a tube furnace at 750 °C and 2 °C min -1 Calcination at a heating rate of 4 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 750 °C for 1 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

[0026] Example 3 A manganese cobalt oxide nitride negative electrode material is prepared similarly to Example 1 by the following steps: (1) Dissolve 4 mmol of soluble manganese chloride and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt chloride and 6 mmol of oxalic acid in 20 mL of organic solvent ethanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 150 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 180 °C for 12 h, wash with ethanol three times, filter, and dry in a vacuum oven at 60 °C for 20 h to obtain a manganese cobalt oxide precursor. (4) The cobalt manganese oxide precursor was heated in a tube furnace at 750 °C and 2 °C min -1 Calcinate at a heating rate of 6 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 750 °C for 1 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

Claims

1. A method for preparing a manganese cobalt oxide nitride negative electrode material, characterized in that: The nitrided manganese cobalt oxide negative electrode material is prepared by nitridation in a chemical solution method and an argon / ammonia mixed atmosphere, including the following steps: (1) Dissolve 4 mmol of soluble manganese salt and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt salt and 6 mmol of oxalic acid in 20 mL of organic solvent, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 100-150 min to form a transparent solution. Then, transfer solution C to a 100 mL Teflon-lined autoclave, heat at 160-180 °C for 12-18 h, wash with ethanol 3-5 times, filter, and dry in a vacuum oven at 60-80 °C for 10-20 h to obtain a manganese cobalt oxide precursor. (4) Heat the manganese cobalt oxide precursor in a tube furnace at 600-750°C, 2-5°C min -1 Calcine at a heating rate of 4 to 8 h to obtain manganese cobaltate; (5) Heating manganese cobalt oxide in an Ar / NH3 mixed atmosphere at 700-750°C for 1-1.5 h to obtain manganese cobalt oxide nitride.

2. The method for preparing a cobalt manganese nitride negative electrode material according to claim 1, characterized in that The manganese salt is one of manganese acetate, manganese nitrate and manganese chloride or a combination thereof.

3. The method for preparing a cobalt manganese nitride negative electrode material according to claim 1, characterized in that The cobalt salt is one of cobalt acetate, cobalt nitrate and cobalt chloride or a combination thereof.

4. The method for preparing a cobalt manganese nitride oxide negative electrode material according to claim 1, characterized in that The organic solvent is one of ethanol, methanol or propanol or a combination thereof.

5. The method for preparing a cobalt manganese nitride oxide negative electrode material according to any one of claims 1 to 4, characterized in that Prepare as follows: (1) Dissolve 4 mmol of soluble manganese acetate and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt acetate and 6 mmol of oxalic acid in 20 mL of organic solvent ethanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 100 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 160 °C for 18 h, wash with ethanol three times, filter, and dry in a vacuum oven at 80 °C for 10 h to obtain a manganese cobalt oxide precursor. (4) Place the cobalt oxide precursor in a tube furnace at a heating rate of 2~5℃min -1 , calcined at 600℃ for 8 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 700 °C for 1.5 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

6. The method for preparing a cobalt manganese nitride oxide negative electrode material according to any one of claims 1 to 4, characterized in that Prepare as follows: (1) Dissolve 4 mmol of soluble manganese nitrate and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt nitrate and 6 mmol of oxalic acid in 20 mL of organic solvent methanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 120 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 180 °C for 12 h, wash with ethanol three times, filter, and dry in a vacuum oven at 60 °C for 20 h to obtain a manganese cobalt oxide precursor. (4) The cobalt manganese oxide precursor was heated in a tube furnace at 750 °C and 2 °C min -1 Calcinate at a heating rate of 4 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 750 °C for 1 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

7. The method for preparing a manganese cobalt oxide negative electrode material according to any one of claims 1 to 4, characterized in that Prepare as follows: (1) Dissolve 4 mmol of soluble manganese chloride and 16 mmol of oxalic acid in 50 mL of distilled water, labeled as solution A. (2) Disperse 2 mmol of soluble cobalt chloride and 6 mmol of oxalic acid in 20 mL of organic solvent ethanol, labeled as solution B, and slowly add solution A to solution B to form solution C; (3) Add 12 mmol of ammonium fluoride to solution C and stir for 150 min to obtain a transparent solution. Then, transfer the transparent solution to a 100 mL Teflon-lined autoclave, heat at 180 °C for 12 h, wash with ethanol three times, filter, and dry in a vacuum oven at 60 °C for 20 h to obtain a manganese cobalt oxide precursor. (4) The cobalt manganese oxide precursor was heated in a tube furnace at 750 °C and 2 °C min -1 Calcinate at a heating rate of 6 h to obtain manganese cobaltate; (5) Manganese cobalt oxide is heated at 750 °C for 1 h in an Ar / NH3 mixed atmosphere to obtain manganese cobalt oxide nitride.

8. A cobalt manganese nitride negative electrode material, characterized in that Prepared according to any one of claims 1 to 7.

9. Use of the manganese cobalt oxide nitride according to claim 8 in a lithium battery negative electrode material.

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