Modified lithium ion battery negative electrode material and preparation method and application thereof

Abstract

The application discloses a modified lithium ion battery negative electrode material and a preparation method and application thereof, and relates to the technical field of battery materials.The preparation method disclosed by the application comprises the following steps: S1: polyvinylidene fluoride is dissolved in NMP, after stirring and dissolving, acetylene black and an active material are continuously added, and stirring is uniformly conducted to obtain a slurry; S2: the slurry is coated on the surface of a copper foil, vacuum drying is conducted, and a coated copper foil is obtained; and S3: the coated copper foil is punched to obtain a negative electrode material.The lithium ion battery negative electrode material prepared by the application has good conductivity and excellent rate performance, can meet the requirements of the industry, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, specifically to a modified lithium-ion battery anode material, its preparation method, and its application. Background Technology

[0002] The high energy density, cleanliness, and convenience of lithium-ion batteries have made them increasingly popular among consumers, with their market share far exceeding that of other battery products. The negative electrode is a crucial component of lithium-ion batteries. However, the theoretical capacity of commercially available graphite negative electrode materials is only 372 mAh / g, significantly limiting their application in negative electrode materials. While transition metal oxides with spinel structures possess theoretical specific capacity and can undergo reversible lithium insertion / extraction reactions with lithium, and exhibit high energy density, they also suffer from characteristics such as easy volume expansion during charge / discharge processes leading to electrode damage and poor conductivity, thus hindering their further practical application.

[0003] Carbon, the 12th element in the periodic table, has very stable physical and chemical properties. Carbon materials, as anode materials, have excellent electrochemical performance and have long been favored by the battery market. They not only have high specific capacity (200-400mAh / g), but also a low potential very close to that of lithium, and good cycle stability. Carbon materials with a loose and porous structure have relatively high potentials for lithium ion insertion and extraction during charging and discharging, resulting in good cycle stability and rate performance. Summary of the Invention

[0004] The purpose of this invention is to provide a modified lithium-ion battery anode material, its preparation method, and its application, thereby solving the following technical problems:

[0005] Existing transition metal oxides are prone to volume expansion during charging and discharging, which can damage the electrodes and result in poor conductivity.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a modified lithium-ion battery anode material includes the following steps:

[0008] S1: Dissolve polyvinylidene fluoride in NMP, stir until dissolved, then add acetylene black and active material, stir until uniform, and obtain slurry;

[0009] S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil;

[0010] S3: Copper foil is deposited and stamped to obtain the negative electrode material.

[0011] As a further aspect of the present invention: the mass ratio of polyvinylidene fluoride, acetylene black, and active material in S1 is 1:1:8.

[0012] As a further aspect of the present invention, the preparation method of the active material includes the following steps:

[0013] A1: Anhydrous zinc chloride and dimethyldibenzonitrile silane were added to a reaction flask, calcined in a muffle furnace under vacuum, washed and dried to obtain component one;

[0014] A2: Add component one and deionized water to the reactor, then add cobalt nitrate hexahydrate, cetyltrimethylammonium bromide and urea, heat to 150-170℃ and keep warm for 1-2 hours to obtain component two;

[0015] A3: The components diethanolamine and triethanolamine are placed in a reactor, ignited and burned to obtain the active material.

[0016] As a further aspect of the present invention: the mass ratio of anhydrous zinc chloride to dimethyldibenzonitrile silane in A1 is 4-8:1.

[0017] As a further aspect of the present invention: the muffle furnace calcination in A1 is specifically carried out at 400-500℃ for 18-24 hours.

[0018] As a further embodiment of the present invention: the mass ratio of component A2, deionized water, cobalt nitrate hexahydrate, cetyltrimethylammonium bromide, and urea is 2-5:300-600:15-20:7.5-10:10-15.

[0019] As a further aspect of the present invention: the mass ratio of component 2 to triethanolamine in A3 is 1:1-1.5.

[0020] A modified lithium-ion battery anode material, characterized in that it is prepared by any one of the above-mentioned preparation methods.

[0021] Application of modified lithium-ion battery anode materials in electrode materials.

[0022] The beneficial effects of this invention are:

[0023] This invention uses dimethyldibenzonitrile silane as a raw material to prepare component one, which is a silicon-containing porous polymer. The silicon-containing porous polymer contains silicon and nitrogen. Using component one as a matrix and cobalt nitrate hexahydrate as a cobalt source, this invention prepares transition metal oxides of cobalt oxide and cobalt tetroxide in a myricetite-like structure. Component one is added during the preparation of the transition metal oxides, which are deposited on the surface and in the pores of component one, thus preparing a modified lithium-ion battery anode material. Component one prepared by this invention has a high specific surface area and abundant porous structure. The doping of silicon and nitrogen elements into the carbon skeleton of component one not only increases the specific surface area of ​​the carbon material, exposing more edge defects in the carbon skeleton to provide more reaction sites, but also enhances the lithium storage capacity of the battery, significantly improving the electrochemical performance of the battery.

[0024] In the preparation of the transition metal oxide of this invention, a first component is added, and the transition metal oxide is deposited on the surface and in the channels of the first component. The transition metal oxide prepared by this invention effectively solves the problem of volume expansion during lithium insertion and shortens the lithium ion migration distance during lithium insertion or de-lithiation. The deposition of the transition metal oxide on the first component not only improves the conductivity of the anode material but also reduces the agglomeration of the transition metal oxide. The uniformly dispersed transition metal oxide and the unique porous matrix prepared in this application provide a continuous conductive network, which greatly promotes the rapid transfer of ions and electrons and effectively reduces the volume fluctuation effect of the transition metal oxide during charge and discharge. The modified lithium-ion battery anode material prepared by this invention has good cycle stability and high conductivity. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] The preparation method of active materials includes the following steps:

[0028] A1: Add 80g of anhydrous zinc chloride and 20g of dimethyldibenzonitrile silane to a reaction flask, heat the mixture to 400℃ in a muffle furnace under vacuum and calcine for 18h, then wash and dry to obtain component one;

[0029] A2: Add 12g of component one and 1800mL of deionized water to the reaction vessel, then add 90g of cobalt nitrate hexahydrate, 45g of cetyltrimethylammonium bromide and 60g of urea. Heat to 150℃ and keep warm for 1h to obtain component two.

[0030] A3: Place 10g of component II and 10g of triethanolamine in a reactor, ignite and burn to obtain the active material.

[0031] Example 2

[0032] The preparation method of active materials includes the following steps:

[0033] A1: Add 120g of anhydrous zinc chloride and 20g of dimethyldibenzonitrile silane to a reaction flask, heat the mixture to 400℃ in a muffle furnace under vacuum and calcine for 24h, then wash and dry to obtain component one;

[0034] A2: Add 12g of component one and 1500mL of deionized water to the reactor, then add 50g of cobalt nitrate hexahydrate, 25g of cetyltrimethylammonium bromide and 40g of urea. Heat to 160℃ and keep warm for 1.5h to obtain component two.

[0035] A3: Place 10g of component II and 12g of triethanolamine in a reactor, ignite and burn to obtain the active material.

[0036] Example 3

[0037] The preparation method of active materials includes the following steps:

[0038] A1: Add 160g of anhydrous zinc chloride and 20g of dimethyldibenzonitrile silane to a reaction flask, heat to 500℃ in a muffle furnace under vacuum and calcine for 24h, wash and dry to obtain component one;

[0039] A2: Add 15g of component one and 1800mL of deionized water to the reaction vessel, then add 60g of cobalt nitrate hexahydrate, 30g of cetyltrimethylammonium bromide and 45g of urea. Heat to 170℃ and keep warm for 2 hours to obtain component two.

[0040] A3: Place 10g of component II and 15g of triethanolamine in a reactor, ignite and burn to obtain the active material.

[0041] Example 4

[0042] A method for preparing a modified lithium-ion battery anode material includes the following steps:

[0043] S1: Dissolve 1g of polyvinylidene fluoride in NMP, stir until dissolved, then add 1g of acetylene black and 8g of the active material prepared in Example 1, stir until uniform, and obtain a slurry;

[0044] S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil;

[0045] S3: Copper foil is deposited and stamped to obtain the negative electrode material.

[0046] Example 5

[0047] A method for preparing a modified lithium-ion battery anode material includes the following steps:

[0048] S1: Dissolve 1g of polyvinylidene fluoride in NMP, stir until dissolved, then add 1g of acetylene black and 8g of the active material prepared in Example 2, stir until uniform, and obtain a slurry;

[0049] S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil;

[0050] S3: Copper foil is deposited and stamped to obtain the negative electrode material.

[0051] Example 6

[0052] A method for preparing a modified lithium-ion battery anode material includes the following steps:

[0053] S1: Dissolve 1g of polyvinylidene fluoride in NMP, stir until dissolved, then add 1g of acetylene black and 8g of the active material prepared in Example 2, stir until uniform, and obtain a slurry;

[0054] S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil;

[0055] S3: Copper foil is deposited and stamped to obtain the negative electrode material.

[0056] Comparative Example 1

[0057] The preparation method of active materials includes the following steps:

[0058] A1: Add 12g of porous carbon and 1800mL of deionized water to the reactor, then add 90g of cobalt nitrate hexahydrate, 45g of cetyltrimethylammonium bromide and 60g of urea. Heat to 150℃ and keep warm for 1h to obtain component one.

[0059] A2: Place 10g of component one and 10g of triethanolamine in a reactor, ignite and burn to obtain the active material.

[0060] Comparative Example 2

[0061] A method for preparing a modified lithium-ion battery anode material includes the following steps:

[0062] S1: Dissolve 1g of polyvinylidene fluoride in NMP, stir until dissolved, then add 1g of acetylene black and 8g of the active material prepared in Comparative Example 1, stir until uniform, and obtain a slurry;

[0063] S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil;

[0064] S3: Copper foil is deposited and stamped to obtain the negative electrode material.

[0065] Experimental content

[0066] Electrode materials were prepared according to the components and methods of Examples 4-6 and Comparative Example 2, respectively.

[0067] Battery assembly: Coin cells were assembled in an argon-filled glove box, with lithium metal sheets used as the reference and counter electrodes. The electrolyte was 1.0M LiPF6 / EC+DMC+EMC (volume ratio 1:1:1), and the separator was a Celgard 2300 polypropylene-polyethylene porous membrane.

[0068] Cyclic voltammetry testing: Cyclic voltammetry testing was performed on the battery using a CHI 760E electrochemical workstation at room temperature. The test temperature was room temperature, the voltage range was 0.01-3V, the voltage scan rate was 0.2mV / s, and the number of scans was 6. The results are shown in Table 1.

[0069] Table 1: Performance Test Data Statistics of Examples 4-6 and Comparative Example 2

[0070]

[0071] As shown in Table 1, the lithium-ion battery anode materials prepared in Examples 4-6 of this invention exhibit good conductivity and excellent rate performance. They meet industry requirements and have promising application prospects.

[0072] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing a modified lithium-ion battery anode material, characterized in that, Includes the following steps: S1: Dissolve polyvinylidene fluoride in NMP, stir until dissolved, then add acetylene black and active material, stir until uniform, and obtain slurry; S2: The paste is coated onto the surface of the copper foil and dried under vacuum to obtain the coated copper foil; S3: Copper foil is deposited and stamped to obtain the negative electrode material; The preparation method of the active material includes the following steps: A1: Anhydrous zinc chloride and dimethyldibenzonitrile silane were added to a reaction flask, calcined in a muffle furnace under vacuum, washed and dried to obtain component one; A2: Add component one and deionized water to the reactor, then add cobalt nitrate hexahydrate, cetyltrimethylammonium bromide and urea, heat to 150-170℃ and keep warm for 1-2 hours to obtain component two; A3: The components diethanolamine and triethanolamine are placed in a reactor, ignited and burned to obtain the active material.

2. The method for preparing a modified lithium-ion battery anode material according to claim 1, characterized in that, In S1, the mass ratio of polyvinylidene fluoride, acetylene black, and active material is 1:1:

8.

3. The method for preparing a modified lithium-ion battery anode material according to claim 1, characterized in that, The mass ratio of anhydrous zinc chloride to dimethyldibenzonitrile silane in A1 is 4-8:

1.

4. The method for preparing a modified lithium-ion battery anode material according to claim 1, characterized in that, The specific calcination process in the muffle furnace for A1 is: 400-500℃, calcination for 18-24 hours.

5. The method for preparing a modified lithium-ion battery anode material according to claim 1, characterized in that, In component A2, the mass ratio of deionized water, cobalt nitrate hexahydrate, cetyltrimethylammonium bromide, and urea is 2-5:300-600:15-20:7.5-10:10-15.

6. The method for preparing a modified lithium-ion battery anode material according to claim 1, characterized in that, In A3, the mass ratio of component 2 to triethanolamine is 1:1-1.

5.

7. A modified lithium-ion battery anode material, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

8. The application of the modified lithium-ion battery anode material according to claim 7 in electrode materials.

Images