CN114464463A - Negative pole piece, preparation method thereof and lithium ion capacitor based on negative pole piece - Google Patents
Negative pole piece, preparation method thereof and lithium ion capacitor based on negative pole piece Download PDFInfo
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- 239000003990 capacitor Substances 0.000 title claims abstract description 25
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims description 26
- 229910001416 lithium ion Inorganic materials 0.000 title claims description 25
- 238000002360 preparation method Methods 0.000 title claims description 17
- 239000011149 active material Substances 0.000 claims abstract description 58
- 239000013543 active substance Substances 0.000 claims abstract description 40
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 8
- 239000010439 graphite Substances 0.000 claims abstract description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 4
- 229910021385 hard carbon Inorganic materials 0.000 claims abstract description 4
- 239000004966 Carbon aerogel Substances 0.000 claims abstract description 3
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910021389 graphene Inorganic materials 0.000 claims abstract description 3
- 229910021384 soft carbon Inorganic materials 0.000 claims abstract description 3
- 239000006258 conductive agent Substances 0.000 claims description 23
- 239000011230 binding agent Substances 0.000 claims description 20
- 239000002562 thickening agent Substances 0.000 claims description 18
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 15
- 238000004898 kneading Methods 0.000 claims description 13
- 238000005096 rolling process Methods 0.000 claims description 13
- 239000002002 slurry Substances 0.000 claims description 12
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 238000007873 sieving Methods 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 6
- 239000011267 electrode slurry Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 4
- 239000000853 adhesive Substances 0.000 claims description 4
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 4
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 239000011889 copper foil Substances 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 2
- 239000006230 acetylene black Substances 0.000 claims description 2
- 239000002134 carbon nanofiber Substances 0.000 claims description 2
- 239000002041 carbon nanotube Substances 0.000 claims description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 2
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 claims description 2
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 claims description 2
- 239000003273 ketjen black Substances 0.000 claims description 2
- 229920000609 methyl cellulose Polymers 0.000 claims description 2
- 239000001923 methylcellulose Substances 0.000 claims description 2
- 235000010981 methylcellulose Nutrition 0.000 claims description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- LNAZSHAWQACDHT-XIYTZBAFSA-N (2r,3r,4s,5r,6s)-4,5-dimethoxy-2-(methoxymethyl)-3-[(2s,3r,4s,5r,6r)-3,4,5-trimethoxy-6-(methoxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6r)-4,5,6-trimethoxy-2-(methoxymethyl)oxan-3-yl]oxyoxane Chemical compound CO[C@@H]1[C@@H](OC)[C@H](OC)[C@@H](COC)O[C@H]1O[C@H]1[C@H](OC)[C@@H](OC)[C@H](O[C@H]2[C@@H]([C@@H](OC)[C@H](OC)O[C@@H]2COC)OC)O[C@@H]1COC LNAZSHAWQACDHT-XIYTZBAFSA-N 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 8
- 230000010287 polarization Effects 0.000 abstract description 4
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 30
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 11
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 11
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 9
- 238000004146 energy storage Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000007600 charging Methods 0.000 description 4
- 239000002356 single layer Substances 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 238000001291 vacuum drying Methods 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000006256 anode slurry Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010280 constant potential charging Methods 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/32—Carbon-based
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/32—Carbon-based
- H01G11/36—Nanostructures, e.g. nanofibres, nanotubes or fullerenes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
- H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nanotechnology (AREA)
- Electric Double-Layer Capacitors Or The Like (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The scheme discloses a negative pole piece in the field of capacitors, which comprises a negative pole current collector, and a first active material layer and a second active material layer which are sequentially coated on the negative pole current collector, wherein the first active material layer comprises a first active material, and the second active material layer comprises a second active material; the first active substance is at least one of soft carbon, hard carbon, graphite and silicon carbon materials; the second active substance is at least one of graphene, activated carbon, carbon foam and carbon aerogel. The scheme combines the first active material layer and the second active material layer, can effectively relieve the transmission pressure of the electrolyte under high power, reduces polarization internal resistance, and reduces the cycle attenuation caused by insufficient electrolyte.
Description
Technical Field
The invention belongs to the field of lithium ion capacitors, and particularly relates to a negative electrode plate, a preparation method of the negative electrode plate and a lithium ion capacitor based on the negative electrode plate.
Background
Lithium ion batteries and supercapacitors are two representative types of energy storage devices with different and characteristic energy storage principles. Lithium batteries have high energy density but low power density, while supercapacitors have high power density but low energy density. Beyond the energy storage limits of the two types of energy storage devices, the development of energy storage devices with high energy density and high power density is a very challenging problem in the field of chemical energy storage. According to the technical principle, the charging and discharging mechanisms of the lithium ion battery and the super capacitor are different, and how to reasonably design and reasonably fuse the two types is achieved, so that a novel lithium ion capacitor is obtained, and the method is a research hotspot and an industrial problem.
For example, patent with application number CN201910518641.9 proposes a composite negative electrode plate and a preparation method thereof, which is to coat a layer of lithium titanate material in the traditional graphite negative electrode coating, and the material inhibits the loss of active lithium caused by the continuous decomposition and generation of SEI in the continuous charging and discharging process of the conventional graphite negative electrode through lithium titanate, thereby slightly improving the cycle life of the battery. However, the two materials of the negative electrode plate are both lithium battery negative electrode materials, and the battery property of the materials is mainly exerted, so that the dynamic performance limit of the lithium ion battery in the charging and discharging process cannot be broken through.
Disclosure of Invention
The invention aims to provide a negative pole piece to improve the dynamic performance, the mass specific energy and the high-rate charge-discharge cycle performance of the negative pole piece.
The negative pole piece comprises a negative pole current collector, and a first active material layer and a second active material layer which are sequentially coated on the negative pole current collector, wherein the first active material layer comprises a first active material, and the second active material layer comprises a second active material; the first active substance is at least one of soft carbon, hard carbon, graphite and silicon carbon material; the second active substance is at least one of graphene, activated carbon, carbon foam and carbon aerogel.
The beneficial effect of this scheme: the first active material in the scheme has high gram specific capacity, so that the negative pole piece has the battery characteristic, a larger surface area adhesion surface can be improved, and the using amount of the binder is reduced. The second active material has a high capacitance characteristic, can rapidly adsorb lithium ions, and has a high electrolyte adsorption capacity. Through the combination of the first active material layer and the second active material layer, the transmission pressure of the electrolyte under high power can be effectively relieved, the polarization internal resistance is reduced, and the cycle attenuation caused by insufficient electrolyte is reduced.
Further, the first active material D90Less than 10 μm.
Further, the second active material D90Less than 10 μm, and specific surface area greater than 200m2/g。
Further, the thicknesses of the first active material and the second active material are d1 and d2, respectively; d of the first active substance90< D1, D of the second active substance90＜d2。
The application also provides a preparation method of the negative pole piece, which comprises the following steps:
step one, preparing a first active substance, a conductive agent, a binder and a thickening agent; dissolving a thickening agent in deionized water, adding a first active substance and a conductive agent for kneading, and kneading until the fineness is the particle size D of the first active substance90Adding a binder, and sieving to obtain negative electrode slurry A;
step two, preparing a second active substance, a conductive agent, a binder and a thickening agent; dissolving a thickening agent in deionized water, adding a second active substance and a conductive agent for kneading, kneading until the fineness is the particle size D90 of the second active substance, adding a binder, and sieving to obtain negative electrode slurry B;
coating the slurry A on a copper foil, drying to obtain a first active material layer, coating the slurry B on the surface of the first active material layer, and drying to obtain a second active material layer; rolling the second active material layer to a specified thickness twice, wherein the first rolling rate is 85-99%, and the second rolling rate is 50-95%; and then slitting to obtain the negative pole piece.
Further, the thickness of the first active material layer is 5-100 μm, and the thickness of the second active material layer is 5-100 μm.
Further, the mass ratio of the first active substance to the conductive agent to the adhesive to the thickening agent is 85-98: 0-5: 0.5-8; the mass ratio of the second active substance to the conductive agent to the adhesive to the thickening agent is 85-98: 0 to 5:0.5 to 8.
Further, the conductive agent is one or more of conductive carbon black, conductive graphite, acetylene black, ketjen black, carbon nanofibers and carbon nanotubes, the binder is one or more of SBR, HPMC, PTFE, PEO or PVA, and the thickener is one or more of sodium carboxymethylcellulose (CMC), methylcellulose and sodium carboxymethylcellulose.
The scheme has the advantages that: the first active material layer with the battery characteristic and the second active material layer with the high-capacitance characteristic are reasonably cooperated, and the second active material layer has the characteristic of high pore specific surface area, so that the compaction density is low, the electrolyte adsorption capacity is high, the electrolyte transmission pressure under high power can be effectively relieved, the polarization internal resistance is reduced, and the cycle attenuation caused by insufficient electrolyte is reduced. The prepared lithium ion capacitor has the characteristics of double layers of battery and capacitor, and has the characteristics of high specific energy, high dynamics and high cycle performance.
Based on the negative pole piece, this application still provides a lithium ion capacitor who contains above-mentioned negative pole piece.
Detailed Description
The following is a detailed description of the embodiments of the present invention, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are included in the scope of the present invention as claimed in the claims.
The lithium ion capacitors 1 to 2 of the examples 1 to 3 and the comparative examples were prepared in the following manner
(1) Preparation of positive pole piece
LiCO serving as a positive electrode active material2The conductive agent SP and the binder PVDF are mixed according to the mass ratio of 90: 5:5, adding solvent NMP, stirring in a double-planet stirrer, sieving to obtain uniform anode slurry, coating, vacuum drying, rolling and cutting to obtain the anode piece.
(2) Preparation of negative pole piece
Preparation of i Single layer Battery type active Material layer negative Pole piece (comparative example 1 negative Pole piece is prepared according to the Single layer Battery type active Material layer negative Pole piece)
The negative electrode sheet of comparative example 1 was prepared with reference to the proportions of table 1:
preparing a first active substance, a conductive agent SP, a binder SBR and a thickening agent CMC according to the mass ratio of 95:1:2:2, dissolving the CMC in deionized water, adding the first active substance and the conductive agent SP, kneading until the fineness of the slurry is reached to the particle size D of the first active substance90Adding a binder SBR, sieving to obtain uniform non-agglomerated negative pole slurry, coating, vacuum drying, rolling to a specified thickness for one time, and slitting to obtain a negative pole piece.
ii preparation of Single-layer capacitive active substance layer negative electrode sheet (comparative example 2 negative electrode sheet preparation according to Single-layer Battery capacitive active substance layer negative electrode sheet)
The negative electrode sheet of comparative example 2 was prepared with reference to the proportions of table 1:
preparing a second active substance, a conductive agent SP, a binder SBR and a thickening agent CMC according to a mass ratio of 89:1:5:5, mixing according to a mass ratio, dissolving the CMC in a deionized water system, adding the second active substance and the conductive agent SP, kneading and kneading until the fineness of the slurry reaches the fineness of a second active substance D90Adding a binder SBR, sieving to obtain uniform non-agglomerated negative pole slurry, coating, vacuum drying, rolling to a specified thickness for one time, and slitting to obtain a negative pole piece.
iii preparation of negative electrode sheet with double active material layer (examples 1 to 3 preparation of negative electrode sheet with double active material layer)
The negative electrode pieces of examples 1 to 3 were prepared with reference to the formulation of table 1:
preparing a first active substance, a conductive agent SP, a binder SBR and a thickening agent CMC according to a mass ratio of 93:1:3:3, dissolving the CMC in deionized water, adding the first active substance and the conductive agent SP, kneading until the slurry fineness reaches a first active substance D, wherein the mass ratio of the CMC to the deionized water is 1:4090Adding a binder SBR, and sieving to obtain uniform non-agglomerated negative electrode slurry A.
Preparing a second active substance, a conductive agent SP, a binder SBR and a thickening agent CMC according to the mass ratio of 92:2:3:3, dissolving the CMC in deionized water, wherein the mass ratio of the CMC to the deionized water is 1:40, adding the second active substance and the conductive agent SP, kneading the slurry until the fineness of the second active substance D is reached90And adding a binder SBR, and sieving to obtain uniform non-agglomerated negative electrode slurry B.
Coating the slurry A on a copper foil, drying to obtain a first active material layer, coating the slurry B on the surface of the first active material layer, and drying to obtain a second active material layer; rolling the second active material layer twice to a specified thickness rolling rate, wherein the first rolling rate of the pole piece is 85-99%, and the second rolling rate of the pole piece is 50-95%.
(3) Lithium ion capacitor preparation
And assembling the negative pole piece into a soft-package laminated lithium ion capacitor according to the prior art.
The lithium ion capacitor test method comprises the following steps:
(1) a mass specific energy test method;
at normal temperature, a lithium ion capacitor 1C is manufactured, constant-current and constant-voltage charging is carried out until the voltage is 4.2V, the cut-off current is 0.05C, the discharge termination voltage is 2V, the theoretical energy is recorded, and the energy is divided by the mass of the lithium ion capacitor, so that the mass specific energy of the lithium ion capacitor is obtained;
(2) a specific power test method;
and charging to 4.2V, testing the internal resistance R of the energy storage device by using an internal resistance instrument, wherein I is (4.2-2)/R is 2.2/R, recording the maximum power by using an IA constant current pulse, and dividing the maximum power by the mass of the lithium ion capacitor to obtain the actual specific power of the lithium ion capacitor.
And calculating the limit specific power according to the standard of the super capacitor for the vehicle (QC/T741-2014).
(3) A cyclic test method;
and (5) performing a 10C/20C charge and discharge performance test, stopping the test when the capacity retention rate is lower than 80%.
TABLE 1 relevant parameters of negative electrode sheets provided in examples 1-3 and comparative examples 1-2
TABLE 2 test structures of lithium ion capacitors prepared in examples 1-3 and comparative examples 1-2
As can be seen from example 1 and comparative example 1 of table 2: the actual test specific power of the pure lithium ion material is far lower than the calculated specific power, the test specific power of the double-layer designed negative pole piece is close to the calculated specific power, and the limit discharge almost has no polarization resistance.
As can be seen from examples 1 to 3 in table 2, the same tendency is observed when the first active material is graphite or a hard carbon material and the second active material is activated carbon or a gel thereof.
As can be seen from example 1 and comparative example 2 of table 2: the addition of the first active material (the battery type active layer) can greatly improve the specific surface gram capacity of the negative electrode, can greatly improve the mass specific energy of the lithium ion capacitor, has a superposition effect on the double-layer negative electrode, greatly reduces the weight of the inactive material, and can also greatly provide the specific power. The lithium ion capacitor prepared by the method has discharge non-polarized internal resistance, so that the lithium ion capacitor has better dynamic performance, higher mass specific energy and high rate cycle performance.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A negative pole piece is characterized in that: the negative electrode current collector comprises a negative electrode current collector body, and a first active material layer and a second active material layer which are sequentially coated on the negative electrode current collector body, wherein the first active material layer comprises a first active material, and the second active material layer comprises a second active material; the first active substance is at least one of soft carbon, hard carbon, graphite and silicon carbon material; the second active substance is at least one of graphene, activated carbon, carbon foam and carbon aerogel.
2. The negative electrode tab of claim 1, wherein: the first active material D90Less than 10 μm.
3. The negative electrode tab of claim 2, wherein: the second active material D90Less than 10 μm, and specific surface area greater than 200m2/g。
4. The negative electrode tab of claim 3, wherein: the thicknesses of the first active material and the second active material are d1 and d2, respectively; d of the first active substance90< D1, D of the second active substance90＜d2。
5. The preparation method of the negative pole piece according to claim 4, characterized in that: the method comprises the following steps:
step one, preparing a first active substance, a conductive agent, a binder and a thickening agent; dissolving a thickening agent in deionized water, adding a first active substance and a conductive agent for kneading, and kneading until the fineness is the particle size D of the first active substance90Adding a binder, and sieving to obtain negative electrode slurry A;
step two, preparing a second active substance, a conductive agent, a binder and a thickening agent; dissolving a thickening agent in deionized water, adding a second active substance and a conductive agent for kneading, kneading until the fineness is the particle size D90 of the second active substance, adding a binder, and sieving to obtain negative electrode slurry B;
coating the slurry A on a copper foil, drying to obtain a first active material layer, coating the slurry B on the surface of the first active material layer, and drying to obtain a second active material layer; rolling the second active material layer to a specified thickness twice, wherein the first rolling rate is 85-99%, and the second rolling rate is 50-95%; and then slitting to obtain the negative pole piece.
6. The preparation method of the negative pole piece according to claim 5, characterized in that: the thickness of the first active material layer is 5-100 μm, and the thickness of the second active material layer is 5-100 μm.
7. The preparation method of the negative pole piece according to claim 6, characterized in that: the mass ratio of the first active substance to the conductive agent to the adhesive to the thickening agent is 85-98: 0-5: 0.5-8; the mass ratio of the second active substance to the conductive agent to the adhesive to the thickening agent is 85-98: 0 to 5:0.5 to 8.
8. The preparation method of the negative pole piece according to claim 7, characterized in that: the conductive agent is one or a combination of more of conductive carbon black, conductive graphite, acetylene black, Ketjen black, carbon nanofibers and carbon nanotubes, the binder is one or a combination of more of SBR, HPMC, PTFE, PEO or PVA, and the thickening agent is one or a combination of more of sodium carboxymethylcellulose, methylcellulose and sodium carboxymethylcellulose.
9. A lithium ion capacitor, characterized in that: the negative electrode plate comprises the negative electrode plate of any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210058978.8A CN114464463A (en) | 2022-01-17 | 2022-01-17 | Negative pole piece, preparation method thereof and lithium ion capacitor based on negative pole piece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210058978.8A CN114464463A (en) | 2022-01-17 | 2022-01-17 | Negative pole piece, preparation method thereof and lithium ion capacitor based on negative pole piece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114464463A true CN114464463A (en) | 2022-05-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210058978.8A Pending CN114464463A (en) | 2022-01-17 | 2022-01-17 | Negative pole piece, preparation method thereof and lithium ion capacitor based on negative pole piece |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114464463A (en) |
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- 2022-01-17 CN CN202210058978.8A patent/CN114464463A/en active Pending
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