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CN114447271A - Preparation method of electrode plate, electrode plate and lithium ion battery - Google Patents

Preparation method of electrode plate, electrode plate and lithium ion battery Download PDF

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Publication number
CN114447271A
CN114447271A CN202111649176.6A CN202111649176A CN114447271A CN 114447271 A CN114447271 A CN 114447271A CN 202111649176 A CN202111649176 A CN 202111649176A CN 114447271 A CN114447271 A CN 114447271A
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active material
electrode
electrode plate
electrode sheet
solvent
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CN114447271B (en
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张彩霞
吴子夏
李子坤
任建国
贺雪琴
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Shenzhen Beiteri New Energy Technology Research Institute Co ltd
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Shenzhen Beiteri New Energy Technology Research Institute Co ltd
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    • 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
    • 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
    • H01M4/139—Processes of manufacture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The application relates to the technical field of lithium ion batteries, in particular to a preparation method of an electrode plate, the electrode plate and the lithium ion battery. The electrode plate with the structure is beneficial to the transmission of lithium ions, the porosity of the lithium ion electrode plate can be improved under the same compaction density, the liquid absorption time of the lithium ion electrode plate can be obviously reduced, the lithium ion transmission rate is further improved, and the electrical property of a lithium ion battery is improved.

Description

Preparation method of electrode plate, electrode plate and lithium ion battery
Technical Field
The application relates to the technical field of lithium ion batteries, in particular to a preparation method of an electrode plate, the electrode plate and the lithium ion battery.
Background
With the continuous development of science and technology, the application field of lithium ion batteries is expanded from portable electronic products to the fields of electric automobiles, energy storage power supplies, aviation and the like. Especially, large-scale electric equipment such as an electric automobile needs to have a certain driving range and a cycle life matched with that of the electric automobile on the premise of ensuring safety, so that higher requirements on the energy density, the cycle life and the rate capability of the lithium ion battery are provided.
There are various ways to increase the energy density, for example, the energy density can be increased by increasing the thickness of the positive and negative electrode sheets, increasing the compaction density of the active material for tight assembly, and increasing the gram volume of the active material. In contrast, increasing the thickness of the electrode plate is the most direct method for improving the energy density of the battery, and compared with improving the compaction density, on one hand, the method can obviously reduce the use amount of the positive and negative current collectors and the diaphragm and save the material cost, and on the other hand, the method can obviously reduce the working procedure amount of battery production such as coating, drying, compaction, slitting, assembly and the like of the electrode plate and save the production cost. However, the increase in the thickness of the electrode sheet may cause problems of a decrease in the transmission rate of lithium ions and uneven wetting of the electrolyte.
The transmission dynamics of the electrode plate is closely related to the microstructure of the electrode plate, the pore structures in the electrode plate and on the surface of the electrode plate play an important role in the transmission speed of lithium ions, and particularly, under the condition that the thickness of the electrode reaches a certain degree, the problems of reduction of the transmission speed of the lithium ions and uneven soaking of electrolyte caused by the increase of the thickness of the electrode plate can be solved by obtaining an ideal pore structure. In the related art, reduced diffusion path lengths and ohmic resistance can be achieved using 3D microstructured electrodes, resulting in higher capacity and power density. However, 3D microstructured electrodes are expensive and involve additional complex manufacturing steps. There is also a method of adding an insoluble organic solvent, i.e., a secondary fluid, while dispersing graphite and a conductive agent in an aqueous binder solution, to form a capillary suspension across a sample network, thereby achieving the effect of producing a high-porosity microstructure, which requires the addition of an organic solvent, i.e., a secondary fluid, followed by removal by baking evaporation, which increases the cost and is not easily removed cleanly.
Disclosure of Invention
The application provides a preparation method of an electrode plate, the electrode plate and a lithium ion battery, and aims to solve the problems of complex manufacturing steps, high cost, organic solvent residue and the like existing in the conventional method for changing the pore structure of the electrode plate.
In a first aspect, the present application also provides a method for manufacturing an electrode sheet using a first active material and a second active material as raw materials, the first active material having a contact angle θ1The contact angle of the second active material is theta2Where 0 DEG < theta1≤40°，50°≤θ2≤90°。
In the scheme, the electrode plate is prepared by using two active materials with different contact angles, wherein the contact angle theta of the first active material1Greater than 0 DEG and less than or equal to 40 DEG, and a contact angle theta of the second active material2The contact angle of the first active material is small, the wettability is good, when the electrode plate is prepared, the first active material is preferentially soaked by a solvent, the contact angle of the second active material is large, the interfacial tension is large, when the electrode plate is prepared, liquid drops surrounded by particle clusters can be formed, a liquid bridging network is formed with the first active material, and the porous electrode plate with capillary pores distributed on the surface can be obtained after the suspension slurry with the liquid bridging network structure is coated and dried.
With reference to the first aspect, in one possible embodiment, when the first active material and the second active material are both cathode materials, the oil absorption value of the first active material is 12 to 20mL/100g, and the oil absorption value of the second active material is 3 to 10mL/100 g; when the first active material and the second active material are both anode materials, the oil absorption value of the first active material is 45 to 80mL/100g, and the oil absorption value of the second active material is 30 to 39mL/100 g.
In combination with the first aspect, in one possible embodiment, the method of preparation comprises any one or combination of more of dosing, coating, drying, rolling.
In a possible embodiment, in combination with the first aspect, the compounding process is specifically to mix a mixture including the first active material, the second active material, the conductive agent, the binder, and the solvent uniformly.
With reference to the first aspect, in a possible implementation manner, the ingredient process specifically includes: uniformly mixing the first active material and the second active material to obtain an electrode active material; and uniformly mixing the electrode active material with a conductive agent, an adhesive and a solvent to prepare the electrode slurry.
In a possible embodiment in combination with the first aspect, the contact angle refers to a contact angle between the active material and the solvent.
With reference to the first aspect, in a possible embodiment, the production method satisfies at least one of the following features (1) to (4):
(1) the solvent is N-methyl pyrrolidone or water;
(2) the mass percentages of the first active material and the second active material are (10-80): (90-20);
(3) the first active material and the second active material respectively and independently comprise at least one of ternary materials, lithium iron phosphate, artificial graphite, natural graphite, silicon monoxide and silicon carbon;
(4) the mass ratio of the electrode active material, the conductive agent, the binder, and the solvent is 95-99: 1-3: 0.8-2.0: 30-48.
In a second aspect, the present application provides an electrode sheet obtained by the preparation method of the first aspect, wherein capillary holes are present in the electrode sheet, and at least a portion of the capillary holes extend from the surface of the electrode sheet to the interior of the electrode sheet.
In the above scheme, the electrode plate has pores, and at least a part of the pores can extend from the surface of the electrode plate to the interior of the electrode plate, so that the structure is favorable for lithium ion transmission. Under the same compaction density, the porosity of the lithium ion pole piece can be improved, the liquid absorption time of the lithium ion pole piece can be obviously reduced, the lithium ion transmission rate is further improved, and the electrical property of the lithium ion battery is improved.
In a possible embodiment in combination with the second aspect, the diameter of the capillary pores is 1 μm to 8 μm.
With reference to the second aspect, in a possible embodiment, the porosity of the lithium ion electrode sheet is greater than or equal to 35%.
In a third aspect, the application also provides a lithium ion battery, which comprises the electrode plate or the electrode plate prepared by the preparation method.
The technical scheme of the application has at least the following beneficial effects:
the preparation method of the electrode plate is prepared by using two active materials with different contact angles, wherein the contact angle theta of the first active material1Greater than 0 DEG and less than or equal to 40 DEG, and a contact angle theta of the second active material2The contact angle of the first active material is small, the wettability is good, when the electrode plate is prepared, the first active material is preferentially soaked by a solvent, the contact angle of the second active material is large, the interfacial tension is large, when the electrode plate is prepared, liquid drops surrounded by particle clusters can be formed, a liquid bridging network is formed with the first active material, and the porous electrode plate with capillary pores distributed on the surface can be obtained after the suspension slurry with the liquid bridging network structure is coated and dried.
According to the electrode plate, the capillary holes are formed in the electrode plate, and at least a part of the capillary holes can extend from the surface of the electrode plate to the inside of the electrode plate, so that the structure is favorable for transmission of lithium ions. Under the same compaction density, the porosity of the lithium ion pole piece can be improved, the liquid absorption time of the lithium ion pole piece can be obviously reduced, the lithium ion transmission rate is further improved, and the electrical property of the lithium ion battery is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
Fig. 1 is a scanning electron microscope image of an electrode sheet obtained in example 1 of the present application before rolling;
fig. 2 is a scanning electron microscope image of the electrode sheet obtained in example 1 of the present application after rolling;
FIG. 3 is a scanning electron micrograph of the electrode sheet obtained in comparative example 1 of the present application before rolling;
FIG. 4 is a scanning electron microscope image of the electrode sheet obtained in comparative example 1 of the present application after rolling;
FIG. 5 is a graph showing a comparison of pore size distributions of electrode sheets obtained in example 1 and comparative example 1 of the present application;
FIG. 6 is a drawing showing the liquid absorption test of the electrode sheet obtained in example 1 of the present application;
FIG. 7 is a drawing showing a liquid absorption test of an electrode sheet obtained in comparative example 1 of the present application;
fig. 8 is a graph comparing cycle performance of full cells manufactured from electrode sheets obtained in example 1 of the present application and comparative example 1.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
Detailed Description
While the following is a description of the preferred embodiments of the present invention, it should be noted that those skilled in the art can make various modifications and improvements without departing from the principle of the embodiments of the present invention, and such modifications and improvements are considered to be within the scope of the embodiments of the present invention.
In a first aspect, the present application provides a method for manufacturing an electrode sheet, the electrode sheet being manufactured using a first active material and a second active material as raw materials, a contact angle of the first active material being θ1The contact angle of the second active material is theta2Where 0 DEG < theta1≤40°，50°≤θ2≤90°。
Alternatively, the contact angle θ of the first active material1The angle may be 1 °, 5 °, 8 °, 10 °, 12 °, 15 °, 18 °, 20 °, 25 °, 30 °, 35 °, or 40 °, or may be other values within the above range, which is not limited herein. Contact angle θ of the second active material2The angle may be 50 °, 55 °, 60 °, 65 °, 70 °, 75 °, 80 °, or 90 °, or may be other values within the above range, and is not limited herein.
In the scheme, the electrode plate is prepared by using two active materials with different contact angles, wherein the contact angle theta of the first active material1Greater than 0 DEG and less than or equal to 40 DEG, and a contact angle theta of the second active material2The contact angle of the first active material is small, the wettability is good, when the electrode plate is prepared, the first active material is preferentially soaked by a solvent, the contact angle of the second active material is large, the interfacial tension is large, when the electrode plate is prepared, liquid drops surrounded by particle clusters can be formed, a liquid bridging network is formed with the first active material, and the porous electrode plate with capillary pores distributed on the surface can be obtained after the suspension slurry with the liquid bridging network structure is coated and dried.
The present solution is described in detail below:
with reference to the first aspect, in one possible embodiment, when the first active material and the second active material are both cathode materials, the first active material has an oil absorption value of 12 to 20mL/100g, such as 12mL/100g, 14mL/100g, 16mL/100g, 18mL/100g, 20mL/100g, and the second active material has an oil absorption value of 3 to 10mL/100g, such as 3mL/100g, 4mL/100g, 6mL/100g, 8mL/100g, 10mL/100 g; when the first active material and the second active material are both anode materials, the first active material has an oil absorption value of 45 to 80mL/100g, for example, 45mL/100g, 50mL/100g, 60mL/100g, 70mL/100g, 80mL/100g, and the second active material has an oil absorption value of 30 to 39mL/100g, for example, 30mL/100g, 32mL/100g, 34mL/100g, 36mL/100g, 39mL/100 g.
In the above embodiment, the oil absorption value measuring method includes the steps of:
(a) weighing a solid powder sample with a certain weight and putting the solid powder sample into a mixing chamber;
(b) dropping a solvent (e.g., any one of dibutyl phthalate (DBP), dioctyl phthalate (DOP), linseed oil, deionized water, N-methylpyrrolidone, absolute ethyl alcohol, and acetone) on a solid powder sample at a constant speed and stirring while driving a rotary wing with two motors;
(c) as the amount of solvent absorbed by the solid powder sample increases, the mixture changes from a free-flowing state to a semi-plastic agglomerate, during which the viscosity of the mixture gradually increases and peaks;
(d) the measurement endpoint is the weight of the dropwise added solvent when the torque generated by the change in the viscosity characteristics reaches a set value or reaches a constant percentage of the maximum torque obtained from the torque curve to calculate the oil absorption value (mL/100g) of the sample to the solvent, and the calculation formula is as follows:
Figure BDA0003446310310000051
d is as follows: oil absorption value in mL/100 g; v is: the volume of the solid powder sample absorbing the solvent is mL; m is: the mass of the solid powder sample is in g.
In the above embodiments, the cathode material includes at least one of a ternary material and lithium iron phosphate, and the anode material includes at least one of artificial graphite, natural graphite, silica and silicon carbon.
In the above embodiments, the oil absorption value of the active material is limited to a certain range, which is more favorable for sufficient wetting between the active material and the solvent to form pores.
As an alternative solution, the preparation method comprises any one or a combination of more of dosing, coating, drying and rolling.
Understandably, the electrode slurry can be obtained through the batching process in the preparation method, and the obtained electrode slurry is transferred to a coating machine for coating, then dried and finally rolled.
With reference to the first aspect, in a possible embodiment, the batching process specifically includes: the composite material comprises a first active material, a second active material, a conductive agent, a binder and a solvent which are mixed uniformly.
With reference to the first aspect, in a possible embodiment, the batching process specifically includes: uniformly mixing the first active material and the second active material to obtain an electrode active material; and uniformly mixing the electrode active material with a conductive agent, an adhesive and a solvent to prepare the electrode slurry.
Optionally, the conductive agent may be at least one selected from graphite, carbon black, graphene, carbon nanotube conductive fibers, metal powder, conductive whiskers, conductive metal compounds, and conductive polymers. Specifically, the conductive agent may include Ketjen black (ultra fine conductive carbon black having a particle size of 30-40nm), SP (Super P, small conductive carbon black having a particle size of 40-50nm), S-O (ultra fine graphite powder having a particle size of 0.5-2 μm), KS-6 (large graphite powder having a particle size of 3 μm), acetylene black, VGCF (vapor grown carbon fiber having a tube diameter of 100-300 nm).
Alternatively, the binder may be selected from one of polyvinyl alcohol (PVA), Polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), polyolefins (such as PP, PE, and other copolymers), polyvinylidene fluoride (PVDF), modified SBR rubber.
Alternatively, the type of the solvent may be selected according to the kind of the active material, and particularly, the solvent may be selected from N-methylpyrrolidone or water.
Specifically, the electrode active material, the conductive agent and the adhesive can be mixed in proportion, added into the solvent, and stirred for 5-8 h by a double-planet vacuum stirrer at the rotating speed of 800-1200 r/min to obtain the electrode slurry.
In combination with the second aspect, in one possible embodiment, the contact angle refers to the contact angle between the active material and the solvent.
Understandably, the contact angle θ1Is the contact angle between the first active material and the solvent. Contact angle theta2Is the contact angle between the second active material and the solvent.
In a possible embodiment in combination with the second aspect, the solvent is N-methylpyrrolidone (NMP) or water.
Alternatively, the water may be deionized water. It is understood that the solvent is N-methylpyrrolidone when the electrode active material is used as a cathode active material, and the solvent is water when the electrode active material is used as an anode active material.
With reference to the second aspect, in some embodiments, the mass percentages of the first active material and the second active material are (10-80): (90-20).
In some embodiments, the first active material and the second active material each independently comprise one of a ternary material, lithium iron phosphate, artificial graphite, natural graphite, silica oxide, or silicon carbon.
In some embodiments, the mass ratio of the electrode active material, the conductive agent, the binder, and the solvent is 95 to 99: 1-3: 0.8-2.0: 30-48.
Alternatively, the mass percentage of the first active material to the second active material may be 80: 20. 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, etc., but it is not limited thereto, and may be other values within the above range. Understandably, by reasonably selecting the mass percentages of the first active material and the second active material in the electrode active material, the obtained electrode active material and a solvent can form a more stable liquid bridging network structure in the process of preparing the electrode plate, and further, the porous electrode plate obtained by coating and drying the suspension slurry with the liquid bridging network structure has an ideal capillary pore structure.
Optionally, the first active material is one of a ternary material, lithium iron phosphate, artificial graphite, natural graphite, silicon monoxide or silicon carbon; the second active material is one of ternary material, lithium iron phosphate, artificial graphite, natural graphite, silicon monoxide or silicon carbon.
The first active material may be a polycrystalline high nickel ternary material, optionally having the chemical formula Lia1(Nix1Coy1Mnz1)O2-b1Nb1Wherein a1 is more than or equal to 0.95 and less than or equal to 1.2, x1 is more than 0.5 and less than 1, y1 is more than 0 and less than 1, x1+ y1+ z1 is 1, b1 is more than or equal to 0 and less than or equal to 1, and N isb1F, P, S, and the polycrystalline high nickel ternary material can be NCM622, NCA811, and NCM 88. The second active material may be a single crystal high nickel ternary material, optionally having the chemical formula Lia2(Nix2Coy2Mnz2)O2-b2Nb2Wherein a2 is more than or equal to 0.95 and less than or equal to 1.2, x2 is more than 0 and less than 1, y2 is more than 0 and less than 1, x2+ y2+ z2 is 1, b2 is more than or equal to 0 and less than or equal to 1, and N isb2One or more selected from F, P, S. Specifically, the single crystal high nickel ternary material may be commercially available NCM622-S, NCM811-S, NCM 88-S.
Alternatively, the mass ratio of the electrode active material, the conductive agent, the binder, and the solvent may be 95:1:0.8:30, 96:2:1:35, 98:3:1.2:40, or 99:1:2.0:48, etc., and may be other values within the above range, which is not limited herein. It can be understood that by reasonably selecting the mass ratio of the electrode active material, the conductive agent, the binder and the solvent, the porous electrode slurry with better rheological property, more uniform pore distribution and more uniform dispersion can be obtained.
In a second aspect, the present application also provides an electrode sheet obtained by using the preparation method of the first aspect, wherein capillary holes are present on the electrode sheet, and at least a portion of the capillary holes extend from the surface of the electrode sheet to the interior of the electrode sheet.
In the scheme, the electrode plate is provided with the capillary holes, and the capillary holes can extend from the surface of the electrode plate to the interior of the electrode plate, so that the structure is favorable for the transmission of lithium ions. Under the same compaction density, the porosity of the lithium ion pole piece can be improved, the liquid absorption time of the lithium ion pole piece can be obviously reduced, the lithium ion transmission rate is further improved, and the electrical property of the lithium ion battery is improved.
The present solution is described in detail below:
as an optional technical scheme of the application, the diameter of the capillary hole is 1-8 μm.
Alternatively, the diameter of the capillary pores may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or the like, or may be other values within the above range, which is not limited herein. It can be understood that when the diameter of the capillary is less than 1 μm, the diameter of the capillary is too small, the porosity of the electrode plate is not significantly increased, so that the lithium ion transport rate is not increased, and when the diameter of the capillary is greater than 8 μm, the diameter of the capillary is too large, which may cause a "foil leakage" phenomenon, and the lithium precipitation of the manufactured battery may occur, which may affect the battery safety.
In combination with the second aspect, in one possible embodiment, the electrode sheet has a porosity of 35% or more.
Alternatively, the porosity of the electrode sheet may be 35%, 40%, 45%, 50%, 55%, or the like, and may be other values within the above range, which is not limited herein. The porosity in the range can obviously reduce the liquid absorption time of the electrode plate, ensure that the liquid absorption time can be shortened by more than 10 percent, improve the transmission rate of lithium ions and improve the electrical property of the lithium ion battery.
In a third aspect, the application also provides a lithium ion battery, which comprises the electrode plate and the electrode plate prepared by the preparation method.
The following examples are given for the purpose of illustration only. The present embodiments are not limited to the following specific examples. The present invention can be modified as appropriate within the scope of protection.
Example 1
The preparation method of the electrode slice comprises the following steps:
selecting a polycrystalline high-nickel ternary material LiNi0.88Co0.06 Mn0.06O2As a first active material, a single crystal high nickel ternary material LiNi0.88Co0.06 Mn0.06O2Mixing a first active material and a second active material according to a mass percentage of 70:30 to obtain an electrode active material as a second active material, wherein the contact angle theta of the first active material and a solvent NMP1Is 18 DEG, and the contact angle theta of the second active material and the solvent NMP2Is 82 deg.. Wherein the contact angle theta1And theta2The method is characterized by adopting an in-situ contact angle test method, wherein the in-situ contact angle test method comprises the following steps: automatically dripping a liquid sample out through an injection system, dripping liquid drops on the surface of the solid sample, obtaining an outline image of the liquid drops through a microscope lens and a camera, and calculating the contact angle of the liquid drops in the image by using a digital image and mathematical operation. The instrument name: OCA15EC video optical contact angle gauge.
The obtained electrode active material was mixed with a conductive agent SP, a binder PVDF5130, and NMP in a proportion of 97.0: 2.0: 1.2: mixing at the ratio of 38.8, and blending by using a double-planet vacuum stirrer to obtain the qualified cathode slurry with the solid content of 72.1% and the viscosity of 5600 mPa.s.
Transferring the qualified slurry to a coating machine for coating and drying to obtain an electrode plate with pores, carrying out scanning electron microscope test on the obtained electrode plate, wherein the test result is shown in figure 1, then rolling to obtain the electrode plate with certain compaction density, and carrying out scanning electron microscope test on the obtained electrode plate, wherein the test result is shown in figure 2.
Example 2
Compared with example 1, except that the contact angle θ of the first active material with the solvent NMP among the electrode active materials1Is 1 DEG, and the contact angle theta of the second active material and the solvent2Is 90 deg., otherwise the same as in example 1.
Example 3
Compared with example 1, except that the contact angle θ of the first active material with the solvent NMP among the electrode active materials1Is 40 DEG, and the contact angle theta of the second active material and the solvent250 deg. and the same as example 1.
Example 4
Compared with example 1, except that the contact angle θ of the first active material with the solvent NMP among the electrode active materials1Is 25 DEG, and the contact angle theta of the second active material and the solvent2Is 75 deg., and is otherwise the same as in example 1.
Example 5
Compared with example 1, except that the contact angle θ of the first active material with the solvent NMP in the electrode active material1Is 32 DEG, and the contact angle theta of the second active material and the solvent2Is 82 deg., and the other is the same as example 1.
Example 6
Compared with example 1, the method is the same as example 1 except that the weight percentage of the first active material to the second active material in the electrode active material is 80: 20.
Example 7
Compared with example 1, the present invention is the same as example 1 except that the weight percentage of the first active material to the second active material in the electrode active material is 10: 90.
Example 8
Compared with example 1, the method is the same as example 1 except that the weight percentage of the first active material to the second active material in the electrode active material is 40: 60.
Example 9
Compared to example 1, except that the electrode active material was mixed with the conductive agent SP, the binders PVDF5130, NMP in a ratio of 95.0: 3.0: 2.0: the mixture was mixed at a ratio of 48.0, and the rest was the same as in example 1.
Example 10
The preparation method of the electrode slice comprises the following steps:
selecting artificial graphite 1 as a first active material and artificial graphite 2 as a second active material, and mixing the first active material and the second active material according to the mass percentage of 60:40 to obtain an electrode active material, wherein the contact angle theta of the first active material and solvent water is1Is 18 degrees, and the contact angle theta of the second active material and the solvent water2Is 56 degrees.
Mixing the obtained electrode active material with a conductive agent SP, a binder CMC, SBR and deionized water according to a weight ratio of 97.0: 1.0:1.4: 1.8: 140.0, and adopting a double-planet vacuum stirrer to prepare the materials to obtain the qualified anode slurry with the solid content of 41.7 percent and the viscosity of 3100 mPa.s.
And transferring the qualified slurry to a coating machine for coating, drying and rolling to obtain the electrode plate with certain compacted density.
Comparative example 1
Compared with example 1, the same as example 1 except that the electrode active material was the first active material. And (3) carrying out scanning electron microscope testing on the electrode sheet before rolling, wherein the testing result is shown in fig. 3, then rolling to obtain the electrode sheet with certain compaction density, and carrying out scanning electron microscope testing on the obtained electrode sheet, wherein the testing result is shown in fig. 4.
Comparative example 2
Compared with example 1, the same as example 1 except that the electrode active material was the second active material.
Comparative example 3
Example 1 was compared with example 1 except that the electrode active material was the second active material and the contact angle of the second active material with the solvent was 95 °.
Comparative example 4
The same as example 10 except that the contact angle θ of the second active material was 32 ° as compared with example 10.
Effect analysis
The electrode sheets obtained in the above examples and comparative examples were subjected to the following performance tests:
1. and (3) testing pore size distribution: porosity test method (refer to GB/T21650.1-2008 mercury porosimetry method and gas adsorption method for determining solid material pore size distribution and porosity part 1), wherein the name of the apparatus is an AutoPore9510 mercury porosimeter and the model is Micromeritics AutoPore 9510. The test method is as follows:
(1) preparing a sample: drying the sample at high temperature, wherein the specific temperature and time are selected according to the material characteristics and the requirements of customers;
(2) weighing a sample: 2.25 +/-0.05 g of a double-sided positive plate, 0.15 +/-0.05 g of a double-sided negative plate, and cutting the width of the plate to be about 10 mm;
(3) loading a sample: placing the sample in a dilatometer;
(4) sealing the dilatometer: sealing the head ground sealing glass surface with an Abies real volume sealing ester;
(5) installing an expansion meter for low-pressure analysis;
(6) and (4) high-pressure analysis. The dilatometer was removed from the low pressure station port and installed into the high pressure chamber for high pressure analysis.
2. Liquid absorption test: the instrument name is pipette P100(10-100 uL). Rolling the pole piece according to the process compaction density requirement, and cutting the pole piece into a rectangle with the length of 200mm and the width of 30 mm; sucking the calibrated pipettor into electrolyte (10uL) and vertically dropping the pipettor onto the surface of the pole piece, and simultaneously pressing a stopwatch to start timing; and stopping after the electrolyte is completely diffused, and recording the total time as the liquid absorption time of the pole piece.
3. And (3) testing the cycle performance: matching the electrode plates obtained in the above examples 1-9 and comparative examples 1-3 with a conventional graphite anode plate (prepared from artificial graphite, SP, CMC and SBR according to the proportion of 96.0:1.0:1.4: 1.6) to carry out battery assembly, liquid injection, formation and capacity grading to obtain a battery; the electrode sheets obtained in example 10 and comparative example 4 were used together with a conventional cathode sheet (made of LiNi)0.88Co0.06 Mn0.06O2SP, CNT and PVDF are prepared according to the proportion of 97.3:1.0:0.5: 1.2) and are matched to carry out battery assembly, liquid injection, formation and capacity grading to obtain a battery; the electrochemical performance of the battery is tested by adopting a new Wille 5V6A battery test cabinet, the voltage range is 3.0-4.2V, the charge-discharge current is 1C, the 1500-cycle retention rate is 1500 th discharge specific capacity/first discharge specific capacity, the gram capacity (test parameter) is battery capacity/active material weight, and the active material weight comprises the total weight of the first active material and the second active material.
TABLE 1 comparison table of basic properties of electrode sheets obtained in examples and comparative examples
Figure BDA0003446310310000121
Table 2 comparison table of basic properties of all batteries manufactured by electrode sheets obtained in examples and comparative examples
Figure BDA0003446310310000122
Figure BDA0003446310310000131
As can be seen from the experimental results obtained in examples 1 to 10 and comparative examples 1 to 4 of table 1, in conjunction with fig. 5, the porosity of the electrode sheet prepared by the preparation method of the present application is up to 35% or more, and the pore size distribution is in the range of 1 μm to 8 μm, whereas the porosity of the electrode sheet prepared by using a single first active material as an electrode active material is 32%, which is significantly lower than the porosity of the electrode sheet of the present application, and the pore size distribution is in the range of 0 to 1 μm, which is smaller than the pore size distribution range of the electrode sheet of the present application. The porosity of the electrode plate prepared by using a single second active material as an electrode active material can reach 43.5 percent, which is obviously higher than that of the electrode plate, but the pore size distribution is within the range of 2-15 mu m and is larger than that of the electrode plate, so that the phenomenon of foil leakage can be caused, and lithium precipitation of the prepared battery can be caused, and the safety of the battery is influenced. When the contact angle of the selected electrode active material with the solvent is greater than 90 °, the prepared slurry is not well wetted with the solvent, resulting in the precipitation of the slurry. When two kinds of artificial graphite with contact angles within the range of 0-40 degrees but different specific contact angle values are selected to prepare the anode piece, the obtained anode piece has no capillary phenomenon, the porosity is obviously low, the first effect and the gram capacity of the anode are lower than those of the embodiment of the invention, and the cycle life at normal temperature is shortened. As can be seen from the experimental results of examples 1 to 10 of table 2, the full cell capacity, the first efficiency and the battery cycle performance prepared from the electrode sheet of the present application are excellent. As can be seen from the experimental results of example 1 and comparative examples 1 to 3, the full cell capacity, the first efficiency and the battery cycle performance prepared by the electrode sheet of the present application are significantly superior to those of the electrode sheet prepared by using a single first active material or a single second active material as an electrode active material, which indicates that the electrode sheet of the present application can effectively improve the electrical properties of the full cell.
As can be seen from the scanning electron microscope images shown in fig. 1 to 4, when the electrode sheet obtained in embodiment 1 of the present application is not rolled, pores are distributed on the surface of the electrode sheet, the pores are uniformly distributed, and the pores on the surface of the electrode sheet after rolling are clearly visible. When the electrode sheet obtained in comparative example 1 is not rolled, no obvious capillary pores are observed on the surface of the electrode sheet, and a plurality of capillary pores are observed on the surface of the electrode sheet after rolling, wherein the number of the capillary pores is obviously less than that of the electrode sheet obtained in example 1.
By performing the liquid absorption tests on the electrode sheets obtained in example 1 of the present application and the electrode sheet obtained in comparative example 1, respectively, it was found that the liquid had spread uniformly around the electrode sheet obtained in example 1 of the present application at a liquid absorption time of 120 seconds, as shown in fig. 6. In contrast, the electrode sheet obtained in comparative example 1 of the present application still had uneven liquid diffusion at a liquid suction time of 220 seconds, as shown in fig. 7. From this can derive, adopt the electrode active material of this application to prepare the electrode slice, can shorten the imbibition time of electrode slice, and then can improve the imbibition speed of electrode slice for battery capacity increases, and battery cycle life improves.
As can be seen from the comparison of cycle performance of the full cells of fig. 8, the full cells prepared using the electrode sheets of the examples of the present application had excellent electrical cycle performance.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. The preparation method of the electrode plate is characterized in that the electrode plate is prepared by using a first active material and a second active material as raw materials, and the contact angle of the first active material is theta1The contact angle of the second active material is theta2Where 0 DEG < theta1≤40°，50°≤θ2≤90°。
2. The production method according to claim 1, wherein when the first active material and the second active material are both cathode materials, the oil absorption value of the first active material is 12 to 20mL/100g, and the oil absorption value of the second active material is 3 to 10mL/100 g; when the first active material and the second active material are both anode materials, the oil absorption value of the first active material is 45-80mL/100g, and the oil absorption value of the second active material is 30-39mL/100 g.
3. The method of claim 1, comprising any one or more of compounding, coating, baking, and rolling in combination.
4. The preparation method according to claim 3, wherein the compounding process specifically comprises: and uniformly mixing a mixture containing the first active material, the second active material, a conductive agent, a binder and a solvent.
5. The preparation method according to claim 3, wherein the compounding process specifically comprises: uniformly mixing the first active material and the second active material to obtain an electrode active material; and uniformly mixing the electrode active material with a conductive agent, an adhesive and a solvent to prepare the electrode slurry.
6. The production method according to claim 5, characterized by satisfying at least one of the following features (1) to (4):
(1) the solvent is N-methyl pyrrolidone or water;
(2) the mass percentages of the first active material and the second active material are (10-80): (90-20);
(3) the first active material and the second active material respectively and independently comprise at least one of ternary materials, lithium iron phosphate, artificial graphite, natural graphite, silicon monoxide and silicon carbon;
(4) the mass ratio of the electrode active material, the conductive agent, the binder, and the solvent is 95-99: 1-3: 0.8-2.0: 30-48.
7. An electrode sheet obtained by the production method according to any one of claims 1 to 6, wherein capillary holes are present in the electrode sheet, and at least a part of the capillary holes extend from the surface of the electrode sheet to the inside of the electrode sheet.
8. The electrode sheet according to claim 7, wherein the diameter of the capillary pores is 1 μm to 8 μm.
9. The electrode sheet according to claim 7, wherein the porosity of the electrode sheet is not less than 35%.
10. A lithium ion battery comprising an electrode sheet produced by the production method according to any one of claims 1 to 6 or an electrode sheet according to any one of claims 7 to 9.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004022507A (en) * 2002-06-20 2004-01-22 Sony Corp Electrode and battery using it
JP2013065468A (en) * 2011-09-16 2013-04-11 Panasonic Corp Lithium ion secondary battery
CN103050700A (en) * 2011-10-17 2013-04-17 中国科学院大连化学物理研究所 Positive electrode material for lithium-air battery or lithium-oxygen battery
CN106229479A (en) * 2016-08-18 2016-12-14 深圳市贝特瑞新能源材料股份有限公司 A kind of lithium ion battery activated carbon composite negative pole material, preparation method and lithium ion battery
CN110085865A (en) * 2018-01-26 2019-08-02 财团法人工业技术研究院 Water-soluble lithium ion battery and be used for electrode therein
CN110741493A (en) * 2017-11-24 2020-01-31 株式会社Lg化学 Negative electrode of lithium secondary battery and lithium secondary battery including the same
CN112467079A (en) * 2020-12-03 2021-03-09 珠海冠宇电池股份有限公司 Silicon-containing negative plate and lithium ion battery comprising same
CN112542571A (en) * 2019-09-23 2021-03-23 珠海冠宇电池股份有限公司 Novel lithium ion battery positive pole piece and preparation method and application thereof
CN112968148A (en) * 2021-03-29 2021-06-15 欣旺达电动汽车电池有限公司 Lithium ion battery negative plate and lithium ion battery
CN113614941A (en) * 2020-10-19 2021-11-05 宁德新能源科技有限公司 Electrochemical device and electronic device comprising same

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004022507A (en) * 2002-06-20 2004-01-22 Sony Corp Electrode and battery using it
JP2013065468A (en) * 2011-09-16 2013-04-11 Panasonic Corp Lithium ion secondary battery
CN103050700A (en) * 2011-10-17 2013-04-17 中国科学院大连化学物理研究所 Positive electrode material for lithium-air battery or lithium-oxygen battery
CN106229479A (en) * 2016-08-18 2016-12-14 深圳市贝特瑞新能源材料股份有限公司 A kind of lithium ion battery activated carbon composite negative pole material, preparation method and lithium ion battery
CN110741493A (en) * 2017-11-24 2020-01-31 株式会社Lg化学 Negative electrode of lithium secondary battery and lithium secondary battery including the same
CN110085865A (en) * 2018-01-26 2019-08-02 财团法人工业技术研究院 Water-soluble lithium ion battery and be used for electrode therein
CN112542571A (en) * 2019-09-23 2021-03-23 珠海冠宇电池股份有限公司 Novel lithium ion battery positive pole piece and preparation method and application thereof
CN113614941A (en) * 2020-10-19 2021-11-05 宁德新能源科技有限公司 Electrochemical device and electronic device comprising same
CN112467079A (en) * 2020-12-03 2021-03-09 珠海冠宇电池股份有限公司 Silicon-containing negative plate and lithium ion battery comprising same
CN112968148A (en) * 2021-03-29 2021-06-15 欣旺达电动汽车电池有限公司 Lithium ion battery negative plate and lithium ion battery

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