Lithium ion battery conductive additive and preparation method thereof

Abstract

The invention discloses a lithium ion battery conductive additive and a preparation method thereof, and solves the technical problems of improving the conductive performance and cycle life of anode and cathode materials of a lithium ion battery. The lithium ion battery conductive additive is graphene, is black powder with grain size distribution of between 10 nanometers and 100 microns, and is a carbonaceous material consisting of single or 1,000 parallel or approximately parallel graphene lamellae. The preparation method comprises oxidization and stripping reduction. Compared with the prior art, the additive has higher electric conductivity; when the additive is applied to the electrode material, the performance of the conventional battery can be greatly improved only by a little amount; the material serving as the conductive additive has good conductive performance, is easy for dispersion, and can effectively enhance the conductive performance and the magnification charging and discharging performance of the electrode material of the lithium ion battery and prolong the cycle life; and the preparation method has low requirements for raw materials and equipment, is easy to control the process, and is suitable for industrialized production.

Description

technical field

[0001] The invention relates to a lithium-ion battery material and a preparation method thereof, in particular to a conductive additive for a lithium-ion battery material and a preparation method thereof. technical background

[0002] Graphene with a two-dimensional structure is the basic unit for forming various sp2 hybridized carbon materials. Graphite is a typical representative of sp2 hybridized carbon materials with a layered structure formed by stacking graphene sheets. Carbon nanotubes can also be seen It is graphene curled into a cylindrical shape. Since the layered structure of graphite was determined, along with the discovery of zero-dimensional fullerene materials, one-dimensional carbon nanotube materials, especially single-walled carbon nanotubes, people have been looking for two-dimensional ideal graphene sheets. It is of great interest whether layer materials can exist stably. In the past, it was always believed that strictly two-dimensional ...

Examples

preparation example Construction

[0024] The preparation method of the lithium ion battery conductive additive of the present invention adopts oxidation, stripping, reduction preparation process, comprises the following steps:

[0025]1. Oxidation of graphite: at room temperature, put a strong acidic solution in a container, use a DC-2006 low-temperature constant temperature bath from Ningbo Xinzhi Biotechnology Co., Ltd., and cool it to 0-4°C in a water bath, preferably 0°C, and place the graphite Add the mixture of powder and nitrate into the above strong acid solution, and use the JJ-1 timing electric mixer of Jincheng Guosheng Experimental Instrument Factory in Jintan City, Jiangsu Province to slowly add a strong oxidant at a stirring speed of 60-3000rpm, and wait until strong After the oxidant is added, continue to stir for 0.5-12h, then control the temperature of the mixture within the range of 32-38°C, continue to stir for 0.5-12h, then slowly add 0.5-4 times the volume, preferably 2 times the strength o...

Embodiment 1

[0050] The graphene powder that embodiment 1 prepares, after testing, specific surface area is 200-400m 2 / g, the conductivity is 5×10 4 -9×10 4 S / m. Such as figure 1 with figure 2 As shown, the particle size distribution is black powder between 5-50μm. Such as image 3 with Figure 4 As shown, it is a carbonaceous material composed of 5-500 layers of parallel or nearly parallel graphene sheets.

[0051] The graphene powder prepared in Example 1 is combined with the lithium iron phosphate positive electrode material, and the preparation method of the positive electrode sheet is as follows: lithium iron phosphate positive electrode material, conductive additive, and binder PVDF are in a mass ratio of 94:3: 3. Using NMP as a solvent, stir in a mixer at a speed of 2000rpm for 4 hours, apply the evenly mixed slurry on an aluminum foil, dry it at 120°C, and then roll it to obtain a positive pole piece; The diaphragm and the negative pole piece were wound, liquid injected, ...

Embodiment 2

[0059] The negative electrode sheets used in Example 2 and Comparative Example 2 are the same, and the manufacturing method is the same as that of the negative electrode sheets in Example 1 and Comparative Example 1. The electrical performance tests of Example 2 and Comparative Example 2 are shown in Table 3.

[0060] Table 3 embodiment 2 and comparative example 2 electrical performance test results

[0061]

[0062] Composite the graphene powder prepared in Example 3 with natural graphite, a negative electrode material for lithium-ion batteries, to make a negative electrode for the battery. The production method of the negative electrode sheet is as follows: graphite negative electrode material, conductive additive graphene powder, binder SBR, thickener CMC according to the mass ratio of 94:2:2.5:1.5, with water as the solvent, in the mixer with a speed of 1500rpm Stir for 3 hours, coat the uniformly mixed slurry on the copper foil, dry at 100°C, and then roll to obtain t...

technical field

[0001] The invention relates to a lithium-ion battery material and a preparation method thereof, in particular to a conductive additive for a lithium-ion battery material and a preparation method thereof. technical background

[0002] Graphene with a two-dimensional structure is the basic unit for forming various sp2 hybridized carbon materials. Graphite is a typical representative of sp2 hybridized carbon materials with a layered structure formed by stacking graphene sheets. Carbon nanotubes can also be seen It is graphene curled into a cylindrical shape. Since the layered structure of graphite was determined, along with the discovery of zero-dimensional fullerene materials, one-dimensional carbon nanotube materials, especially single-walled carbon nanotubes, people have been looking for two-dimensional ideal graphene sheets. It is of great interest whether layer materials can exist stably. In the past, it was always believed that strictly two-dimensional ...

Examples

preparation example Construction

[0024] The preparation method of the lithium ion battery conductive additive of the present invention adopts oxidation, stripping, reduction preparation process, comprises the following steps:

[0025]1. Oxidation of graphite: at room temperature, put a strong acidic solution in a container, use a DC-2006 low-temperature constant temperature bath from Ningbo Xinzhi Biotechnology Co., Ltd., and cool it to 0-4°C in a water bath, preferably 0°C, and place the graphite Add the mixture of powder and nitrate into the above strong acid solution, and use the JJ-1 timing electric mixer of Jincheng Guosheng Experimental Instrument Factory in Jintan City, Jiangsu Province to slowly add a strong oxidant at a stirring speed of 60-3000rpm, and wait until strong After the oxidant is added, continue to stir for 0.5-12h, then control the temperature of the mixture within the range of 32-38°C, continue to stir for 0.5-12h, then slowly add 0.5-4 times the volume, preferably 2 times the strength o...

Embodiment 1

[0050] The graphene powder that embodiment 1 prepares, after testing, specific surface area is 200-400m 2 / g, the conductivity is 5×10 4 -9×10 4 S / m. Such as figure 1 with figure 2 As shown, the particle size distribution is black powder between 5-50μm. Such as image 3 with Figure 4 As shown, it is a carbonaceous material composed of 5-500 layers of parallel or nearly parallel graphene sheets.

[0051] The graphene powder prepared in Example 1 is combined with the lithium iron phosphate positive electrode material, and the preparation method of the positive electrode sheet is as follows: lithium iron phosphate positive electrode material, conductive additive, and binder PVDF are in a mass ratio of 94:3: 3. Using NMP as a solvent, stir in a mixer at a speed of 2000rpm for 4 hours, apply the evenly mixed slurry on an aluminum foil, dry it at 120°C, and then roll it to obtain a positive pole piece; The diaphragm and the negative pole piece were wound, liquid injected, ...

Embodiment 2

[0059] The negative electrode sheets used in Example 2 and Comparative Example 2 are the same, and the manufacturing method is the same as that of the negative electrode sheets in Example 1 and Comparative Example 1. The electrical performance tests of Example 2 and Comparative Example 2 are shown in Table 3.

[0060] Table 3 embodiment 2 and comparative example 2 electrical performance test results

[0061]

[0062] Composite the graphene powder prepared in Example 3 with natural graphite, a negative electrode material for lithium-ion batteries, to make a negative electrode for the battery. The production method of the negative electrode sheet is as follows: graphite negative electrode material, conductive additive graphene powder, binder SBR, thickener CMC according to the mass ratio of 94:2:2.5:1.5, with water as the solvent, in the mixer with a speed of 1500rpm Stir for 3 hours, coat the uniformly mixed slurry on the copper foil, dry at 100°C, and then roll to obtain t...

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