CN117525420A - Functional additive and battery positive electrode, battery negative electrode and lithium ion battery containing functional additive - Google Patents
Functional additive and battery positive electrode, battery negative electrode and lithium ion battery containing functional additive Download PDFInfo
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- CN117525420A CN117525420A CN202311624395.8A CN202311624395A CN117525420A CN 117525420 A CN117525420 A CN 117525420A CN 202311624395 A CN202311624395 A CN 202311624395A CN 117525420 A CN117525420 A CN 117525420A
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- negative electrode
- lithium ion
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- 239000013538 functional additive Substances 0.000 title claims abstract description 81
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 34
- 230000000694 effects Effects 0.000 claims abstract description 11
- 238000005259 measurement Methods 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 3
- 239000002033 PVDF binder Substances 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 15
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 7
- 238000001354 calcination Methods 0.000 claims description 6
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 6
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 6
- 239000000843 powder Substances 0.000 claims description 6
- 235000012239 silicon dioxide Nutrition 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 239000006258 conductive agent Substances 0.000 claims description 3
- 239000006104 solid solution Substances 0.000 claims description 3
- 239000002086 nanomaterial Substances 0.000 claims description 2
- 238000004537 pulping Methods 0.000 claims description 2
- 230000002035 prolonged effect Effects 0.000 abstract description 4
- 239000003795 chemical substances by application Substances 0.000 abstract description 2
- 239000012744 reinforcing agent Substances 0.000 abstract description 2
- 239000002105 nanoparticle Substances 0.000 abstract 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 19
- 229910052744 lithium Inorganic materials 0.000 description 19
- 239000006229 carbon black Substances 0.000 description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 14
- 239000011248 coating agent Substances 0.000 description 14
- 238000000576 coating method Methods 0.000 description 14
- 229910002804 graphite Inorganic materials 0.000 description 14
- 239000010439 graphite Substances 0.000 description 14
- 239000007774 positive electrode material Substances 0.000 description 12
- 238000005520 cutting process Methods 0.000 description 11
- 238000009826 distribution Methods 0.000 description 10
- 239000003792 electrolyte Substances 0.000 description 8
- 239000011149 active material Substances 0.000 description 7
- 239000007773 negative electrode material Substances 0.000 description 7
- 239000000654 additive Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000002048 multi walled nanotube Substances 0.000 description 6
- 239000002391 graphite-based active material Substances 0.000 description 4
- 238000005457 optimization Methods 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 239000006245 Carbon black Super-P Substances 0.000 description 1
- 229910008051 Si-OH Inorganic materials 0.000 description 1
- 229910006358 Si—OH Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- -1 homogenizing Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses a functional additive, a battery positive electrode, a battery negative electrode and a lithium ion battery containing the functional additive, wherein the functional additive comprises the chemical components of xLi 2 O·yLiF·zSiO 2 Wherein x, y and z are element measurement units respectively, and the range is as follows: x is 1.0-3.0, y is 1.0-5.0, and z is 1.0-3.0. The functional additive has nano-sized quantum effect and excellent ionic conductivity and structural stability, and can serve as an anode-cathode interface structure reinforcing agent or a repairing agent. The functional additive prepared by the invention has extremely excellent electrochemical performance in a battery, and through micro-use, the lithium ion battery containing the functional additive has outstanding cycle characteristics, especially under high-temperature cycle, the cycle life of the battery can be prolonged by 50% at maximum.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a functional additive, and a battery positive electrode, a battery negative electrode and a lithium ion battery containing the functional additive.
Background
Lithium ion batteries are a new era of pets in both consumer and power fields. Generally, the energy density of a lithium ion battery is inversely proportional to the cycle life, i.e., the higher the energy density, the worse the cycle life. At present, the cycle life can be prolonged to a certain extent through a series of optimization means such as electrolyte, anode and cathode materials and formula design, but the process system has poor adaptability, long optimization period, high technical requirements and insignificant lifting effect. It is therefore particularly important to develop a technique for rapidly optimizing lifetime.
The positive and negative electrode interface stability of the lithium ion battery is extremely important to the battery cycle performance. Similar series of interface optimization, such as negative electrode film forming additives and positive electrode film forming additives, can improve the cycle life of the lithium ion battery, but generally has no obvious effect, and is improved by about 5-15%. Therefore, research into novel functional additives is currently the focus.
Disclosure of Invention
The invention aims to solve the problems and provide a novel functional additive, a battery positive electrode, a battery negative electrode and a lithium ion battery containing the functional additive, and the cycle life of the battery is greatly prolonged.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
a functional additive for adding in a battery comprises the chemical components of xLi 2 O·yLiF·zSiO 2 Wherein x, y and z are element measurement units respectively, and the range is as follows: x is 1.0-3.0, y is 1.0-5.0, and z is 1.0-3.0.
The functional additive is a solid solution material.
The functional additive is a nano material with quantum effect, and the single particle size is distributed between 5.0nm and 50nm.
The functional additive has some dangling bonds and hydrogen bonds on the surface.
The invention also protects the preparation method of the functional additive, which comprises the following steps: mixing a certain proportion of lithium carbonate, silicon dioxide and PVDF, and then calcining at high temperature to obtain the target product.
Wherein the mass ratio of the lithium carbonate to the silicon dioxide to the PVDF is 100-50:50-10:75-15:25-5; the high temperature range is 500-1200 ℃, and the calcination time is 0.5-2.0 h.
The invention also protects a battery anode, which contains the functional additive, and the addition amount is controlled to be 0.01-1.5% w/w.
The invention also protects a battery cathode which contains the functional additive, and the addition amount is controlled to be 0.01-1.5% w/w.
The invention also protects a lithium ion battery, wherein the lithium ion battery contains the functional additive; the lithium ion battery is subjected to a high-temperature formation stage, and the formation temperature is 45-85 ℃.
The functional additive is directly added into the positive electrode and/or the negative electrode used in the lithium ion battery in the pulping process for carrying out uniform dry powder mixing, or the powder conductive agent of the positive electrode and/or the negative electrode and the functional additive are physically and uniformly mixed in advance and then are added into the positive electrode or the negative electrode dry powder together as a conductive mixture.
Compared with the prior art, the invention has the beneficial effects that:
the functional additive is directly mixed into the active material of the positive electrode or the negative electrode plate, the operation is simple, the cycle life of the battery can be maximally prolonged by 50% in terms of performance, and the effect is quite obvious. In addition, the method is wide in practicability and strong in compatibility, and is not only applicable to all positive electrode material systems of the current lithium ion battery, but also applicable to all negative electrode systems.
The additive prepared by the invention has extremely excellent electrochemical performance in a battery, and provides an important development direction for optimizing the performance of a lithium ion battery.
In particular, compared with the prior art,
firstly, the functional additive has four element components, is rich in functionality, has a nanoscale quantum effect, and shows high ionic conductivity;
secondly, the functional additive has dangling bonds (such as Si-OH bonds) and hydrogen bonds, has good dispersibility in water or oil system media, strong compatibility and low ion resistance attribute, and the dangling bonds or the hydrogen bonds can stabilize edge sites and bond other functional groups, so that the functional additive has the function of stabilizing a structure;
thirdly, the functional additive has stable structure, plays a role in stability and repairability in the process of an anode interface or a cathode interface, can serve as an anode-cathode interface structure reinforcing agent or a repairing agent, enhances SEI or CEI, and achieves the purpose of optimizing cycle performance;
fourth, the functional additive can realize about 50% of cycle performance optimization at maximum under the condition of micro use, especially under high temperature cycle, and the improvement effect is advanced in the industry when the functional additive is applied to lithium ion batteries.
Drawings
Fig. 1: xLi prepared by the present invention 2 O·yLiF·zSiO 2 Is a lens image of the lens.
Fig. 2: normal temperature cycle life graph of example 3.
Fig. 3: high temperature cycle life graph of example 3.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects solved by the invention more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The present embodiment exemplifies only a flexible package battery, but is also applicable to batteries of other cases and structures, such as square steel cases, cylindrical batteries, and the like.
xLi of the present invention 2 O·yLiF·zSiO 2 The preparation method of (2) comprises the following steps: mixing lithium carbonate, silicon dioxide and PVDF in a certain proportion, and calcining at high temperature to obtain the target product, wherein the functional additive is a solid solution material, and not simply and physically mixing the components.
Wherein the mass ratio of the lithium carbonate to the silicon dioxide to the PVDF is 100-50:50-10:75-15:25-5; the high temperature range is 500-1200 ℃, and the calcination time is 0.5-2.0 h.
In the scheme of the invention xLi 2 O·yLiF·zSiO 2 The values of x, y and z have a certain influence on the cycle performance, and only some preferred examples are listed in the detailed description.
Typical battery manufacturing instructions:
preparing a positive electrode plate: the preparation method comprises the steps of adding a positive active material (lithium cobalt oxide LCO, ternary material NCM or other positive materials), an adhesive polyvinylidene fluoride (PVDF) and a conductive agent Super-P (a part of positive pole pieces are added with functional additives in the embodiment of the invention), stirring and homogenizing the mixture into positive slurry according to a certain mass ratio, then coating the positive slurry on a positive current collector in double sides, and drying, compacting, cutting, tabletting and welding lugs to obtain the positive pole pieces.
Preparing a negative electrode plate: the negative electrode active material (artificial graphite, silicon carbon material or other negative electrode materials), an adhesive and a dispersing agent (a part of negative electrode pieces are added with functional additives in the embodiment of the invention), the negative electrode active material is added into deionized water according to the required weight ratio, the deionized water is stirred and homogenized to prepare negative electrode slurry, then the negative electrode slurry is coated on the negative electrode current collector in double sides, and the negative electrode pieces are obtained after drying, compacting, slitting, tabletting and lug welding.
Preparation of a lithium ion battery: and assembling the negative electrode plate, the positive electrode plate and the diaphragm, which are prepared according to the process, to prepare a battery core, loading the battery core into an outer package, adding electrolyte, standing at a high temperature, performing hot-pressing pre-charging, and forming to obtain the lithium ion secondary battery.
In one embodiment, a lithium ion battery is fabricated with a capacity of 5.0Ah, a charge voltage of 4.48V, and a discharge cutoff voltage of 3.0V.
In the invention, the lithium ion battery added with the functional additive needs to undergo a high-temperature formation stage, the formation temperature is 45-85 ℃, the effect is better, the formation is preferably 80 ℃, the formation is more sufficient, the circulation is ensured not to be deformed, the high-temperature performance is better, and otherwise, the circulation failure is easy to be caused by deformation.
Example 1:
2Li with particle size distribution of 5.0-40.0nm 2 O·LiF·2SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the positive electrode active material lithium cobaltate, wherein the adding amount of the functional additive is 0.04% of the mass of the positive electrode lithium cobaltate active material, and then the positive electrode active material lithium cobaltate is prepared by the following steps: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, coating and cutting to obtain the positive electrode plate. Homogenizing and mixing negative graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1 to prepare the negative pole piece. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through 45 ℃ formation.
Example 2:
2Li with particle size distribution of 5.0-40.0nm 2 O·LiF·2SiO 2 And uniformly mixing the functional additive with a certain amount of SP carbon black, adding the mixture into the graphite serving as a negative electrode active material, wherein the adding amount of the functional additive is 0.05% of that of the negative electrode lithium cobaltate active material, homogenizing, coating and cutting the graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1 to obtain the negative electrode plate. Mixing the positive lithium cobalt oxide, the SP, the PVDF and the CNT according to the mass ratio of 98.0:0.5:1.0:0.5, homogenizing, coating and cutting to obtain the positive pole piece. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 60 ℃.
Example 3:
2Li with particle size distribution of 5.0-40.0nm 2 O·LiF·2SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the positive electrode active material lithium cobaltate, wherein the addition amount of the functional additive is 0.05% of the positive electrode lithium cobaltate active material, and then the positive electrode active material lithium cobaltate: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, and then coating and cutting to obtain the positive electrode plate. 2Li with particle size distribution of 5.0-20.0nm 2 O·LiF·2SiO 2 Uniformly mixing the functional additive and a certain amount of SP carbon black, adding the mixture into the graphite serving as a negative electrode active material, wherein the adding amount of the functional additive is 0.05% of that of the negative electrode graphite active material, homogenizing graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1, coating and cutting the homogenized graphite, CMC and SBRAnd obtaining the negative electrode plate. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 80 ℃.
Example 4:
li with particle size distribution of 5.0-40.0nm 2 O·2LiF·2SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the positive electrode active material lithium cobaltate, wherein the addition amount of the functional additive is 0.06% of that of the positive electrode lithium cobaltate active material, and then the positive electrode active material lithium cobaltate: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, coating and cutting to obtain the positive electrode plate. Li with particle size distribution of 5.0-20.0nm 2 O·2LiF·2SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the graphite serving as the anode active material, wherein the adding amount of the functional additive is 0.06% of that of the anode graphite active material, and then the graphite, CMC and SBR are homogenized according to the mass ratio of 98.0:0.9:1.1, and the anode electrode plate is obtained by coating and slitting. The positive electrode and the negative electrode are wound together with the diaphragm, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 85 ℃.
Example 5:
li with particle size distribution of 5.0-40.0nm 2 O·4LiF·2SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the positive electrode active material lithium cobaltate, wherein the addition amount of the functional additive is 0.07% of the positive electrode lithium cobaltate active material, and then the positive electrode active material lithium cobaltate: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, and then coating and cutting to obtain the positive electrode plate. Li with particle size distribution of 5.0-20.0nm 2 O·4LiF·2SiO 2 And uniformly mixing the functional additive with a certain amount of SP carbon black, adding the mixture into the graphite serving as the negative electrode active material, wherein the adding amount of the functional additive is 0.07% of that of the negative electrode graphite active material, homogenizing graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1, and coating and slitting to obtain the negative electrode plate. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 80 ℃.
Example 6:
li with particle size distribution of 5.0-40.0nm 2 O·4LiF·SiO 2 The functional additive and a certain amount of SP carbon black are uniformly mixed and then added into the positive electrode active material lithium cobaltate, wherein the addition amount of the functional additive is 0.08% of the positive electrode lithium cobaltate active material, and then the positive electrode active material lithium cobaltate: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, and then coating and cutting to obtain the positive electrode plate. Li with particle size distribution of 5.0-20.0nm 2 O·4LiF·SiO 2 And uniformly mixing the functional additive with a certain amount of SP carbon black, adding the mixture into the graphite serving as the negative electrode active material, wherein the adding amount of the functional additive is 0.08% of that of the negative electrode graphite active material, homogenizing graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1, and coating and slitting to obtain the negative electrode plate. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 80 ℃.
Comparative example:
lithium cobaltate: SP carbon black: PVDF: homogenizing the multiwall carbon nanotubes according to the mass ratio of 98.0:0.5:1.0:0.5, and then coating and cutting to obtain the positive electrode plate. Homogenizing graphite, CMC and SBR according to the mass ratio of 98.0:0.9:1.1, coating and cutting to obtain the negative electrode plate. The positive electrode, the negative electrode and the diaphragm are wound together, and after the electrolyte is added, the lithium ion secondary battery is obtained through formation at 80 ℃. Examples test results description:
the measurement was carried out for each example, and the measurement results are shown in Table 1:
TABLE 1
Analysis of experimental results:
the test conditions in Table 1 above were all conducted at normal atmospheric pressure at room temperature, and it can be seen that the functional additive prepared in each example was added in an amount of 0.04% to 0.08%, and the capacity of each example was hardly changed after the functional additive was added compared with the comparative group, indicating that the functional additive had no significant effect on the capacity, which can ensure a high energy density design. However, in terms of internal resistance and voltage plateau, the additive is added to the positive electrode and the negative electrode at the same time, so that a slightly high internal resistance and a slightly low voltage plateau are displayed, and when the addition amount is increased from 0.04% to 0.08%, obvious increase and decrease of the internal resistance and the voltage plateau occur, so that the additive is not suitable for being used more. It is evident in terms of cycle performance that the addition of the functional additive to both the positive and negative electrode sheets is more pronounced to enhance cycle performance than if the functional additive was introduced only to the positive or negative electrode. Example 3 the normal temperature cycle was improved by nearly 50% compared to the control group and was extremely shocked. For high temperature cycle, when the functional additive is added from 0.06% -0.08% to the positive and negative electrodes at the same time, compared with example 3, normal temperature cycle and high temperature cycle decrease trend begin to appear, but the comparative group still shows about 40% life improvement, and the same effect is extremely obvious. Therefore, the optimum addition amount can be considered to be 0.05% by combining the results of the respective parameters.
Fig. 2 is a graph of normal temperature cycle life of example 3 and a comparative group, and it can be seen that the prepared lithium ion battery exhibits an excellent cycle life by introducing 0.05% of the functional additive to the positive electrode and the negative electrode according to the present embodiment. After 1400 weeks of 1.0C charge-discharge cycle at 4.0C pulse, still exhibiting a cycle life of higher than 88.0%, significantly higher than 82.3% of the comparative group (1400 cycles), the excellent cycle performance is mainly attributed to the excellent film-forming properties of the additives.
Fig. 3 is a high temperature cycle life curve of example 3 and a comparative group, and it can be seen that the prepared battery exhibits superior high temperature cycle life by introducing 0.08% of the functional additive to the positive and negative electrodes according to the present scheme. Example 3 still exhibited a cycle life of greater than 81.2% after 1.0C charge 1.0C discharge cycle of 900 weeks; the contrast group has almost capacity attenuated to 80% after 620 circles, and the difference is very obvious, which mainly shows that the positive and negative electrodes, especially the positive electrode, have good film forming temperature resistance, stable interface and good high temperature stability under the high temperature condition by introducing the functional additive.
The method for rapidly optimizing the cycle life is not only suitable for a ternary positive electrode, a lithium cobaltate system, a lithium iron phosphate system, a lithium manganese iron phosphate system or a lithium manganate system, but also suitable for a graphite negative electrode, a silicon-oxygen negative electrode, a silicon-carbon negative electrode or a lithium titanate system.
The present invention is not limited to the preferred embodiments, and any simple modification, equivalent replacement, and improvement made to the above embodiments by those skilled in the art without departing from the technical scope of the present invention, will fall within the scope of the present invention.
Claims (10)
1. A functional additive characterized by: the functional additive is used for being added into a battery, and the chemical component of the functional additive is xLi 2 O·yLiF·zSiO 2 Wherein x, y and z are element measurement units respectively, and the range is as follows: x is 1.0-3.0, y is 1.0-5.0, and z is 1.0-3.0.
2. The functional additive according to claim 1, characterized in that: the functional additive is a solid solution material.
3. The functional additive according to claim 1, characterized in that: the functional additive is a nano material with quantum effect, and the single particle size is distributed between 5.0nm and 50nm.
4. The functional additive according to claim 1, characterized in that: the method is characterized in that: the functional additive has some dangling bonds and hydrogen bonds on the surface.
5. A process for the preparation of a functional additive as claimed in any one of claims 1 to 4, characterized in that: mixing a certain proportion of lithium carbonate, silicon dioxide and PVDF, and then calcining at high temperature to obtain the target product.
6. The method for preparing the functional additive according to claim 5, wherein: the mass ratio of the lithium carbonate to the silicon dioxide to the PVDF is 100-50:50-10:75-15:25-5; the high temperature range is 500-1200 ℃, and the calcination time is 0.5-2.0 h.
7. A battery positive electrode, characterized in that: the functional additive according to any one of claims 1 to 4, wherein the addition amount is controlled to be 0.01 to 1.5% w/w.
8. A battery negative electrode, characterized by: the functional additive according to any one of claims 1 to 4, wherein the addition amount is controlled to be 0.01 to 1.5% w/w.
9. A lithium ion battery, characterized in that: the lithium ion battery contains the functional additive as defined in any one of claims 1-4; the lithium ion battery is subjected to a high-temperature formation stage, and the formation temperature is 45-85 ℃.
10. The lithium ion battery of claim 9, wherein: the functional additive is directly added into the positive electrode and/or the negative electrode used in the lithium ion battery in the pulping process for carrying out uniform dry powder mixing, or the powder conductive agent of the positive electrode and/or the negative electrode and the functional additive are physically and uniformly mixed in advance and then are added into the positive electrode or the negative electrode dry powder together as a conductive mixture.
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| CN202311624395.8A CN117525420A (en) | 2023-11-30 | 2023-11-30 | Functional additive and battery positive electrode, battery negative electrode and lithium ion battery containing functional additive |
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