CN113013412A - Negative electrode slurry, negative electrode sheet and lithium ion battery - Google Patents
Negative electrode slurry, negative electrode sheet and lithium ion battery Download PDFInfo
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- 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
- H01M4/624—Electric conductive fillers
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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
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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
- H01M10/058—Construction or manufacture
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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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- H—ELECTRICITY
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- 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
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Abstract
The invention discloses a negative electrode slurry, a negative electrode plate and a lithium ion battery. In a first aspect of the present application, there is provided a negative electrode slurry including a negative electrode active material and a polymer ion conductor which is a homopolymer formed of an oxygen-containing monomer. The negative electrode slurry according to the embodiment of the application has at least the following beneficial effects: after the polymer ion conductor with a specific composition is added into the negative electrode slurry, the viscosity promotion brought by the polymer ion conductor can inhibit the phenomena of fold cracking and the like in the coating and baking process of the pole piece, promote the wettability of the electrode to the electrolyte so as to improve the multiplying power performance of the battery, and can bring about very remarkable promotion to the high-temperature cycle performance of the battery to a great extent, thereby ensuring the service life of the lithium ion battery.
Description
Technical Field
The application relates to the technical field of lithium ion batteries, in particular to negative electrode slurry, a negative electrode plate and a lithium ion battery.
Background
A lithium ion battery is a secondary battery that mainly relies on reversible intercalation and deintercalation of lithium ions between positive and negative electrodes for operation. Compared with other types of batteries, lithium ion batteries have high power characteristics and long service lives, which also makes them widely used in various types of electronic products. Along with the continuous improvement of the market on the demand of the high-energy density lithium ion battery, the charging experience becomes the core pain point of consumers, the use experience of electronic products can be better improved by shortening the charging time, and the method has very important significance for improving the competitiveness of the electronic products. For this reason, various rapid charging techniques have been successively introduced by various manufacturers. However, the current fast charging technology still has many problems to be solved, one of which is the problem of battery heating. The battery heats rapidly in the process of quick charging, quickly reaches a critical value and starts a power reduction mechanism, so that the safety problem caused by continuous and rapid temperature rise is avoided. The power reduction mechanism is also partly set because the lithium ion battery cathode is easy to generate side reaction in the high-temperature cycle process, so that the cycle performance is reduced and the service life is shortened. Therefore, it is necessary to provide an anode slurry having better high-temperature cycle performance.
Disclosure of Invention
The present application is directed to solving at least one of the problems in the prior art. Therefore, the application provides a negative electrode slurry, a negative electrode sheet and a lithium ion battery with good high-temperature cycle performance.
In a first aspect of the present application, there is provided a negative electrode paste including a negative electrode active material and a polymer ion conductor including a homopolymer formed of an oxygen-containing monomer.
The negative electrode slurry according to the embodiment of the application has at least the following beneficial effects:
after the polymer ion conductor with a specific composition is added into the negative electrode slurry, the viscosity promotion brought by the polymer ion conductor can inhibit the phenomena of fold cracking and the like in the coating and baking process of the pole piece, promote the wettability of the electrode to the electrolyte so as to improve the multiplying power performance of the battery, and can bring about very remarkable promotion to the high-temperature cycle performance of the battery to a great extent, thereby ensuring the service life of the lithium ion battery.
In some embodiments of the present application, the homopolymer is a compound of formula (I):
wherein R is1Is an optional alkylene or silylene group, and n is an integer of 10 to 250000.
Wherein, alkylene means alkylene of an optional carbon number, and non-limiting examples thereof include unsubstituted alkylene such as methylene, ethylene, propylene and the like, and substituted alkylene such as isopropylene, diphenylmethylene and the like. The silylene group means an optionally substituted or unsubstituted silylene group, and non-limiting examples thereof include alkyl or aryl substituted silylene groups such as dimethylsilylene group, diphenylsilylene group, methylphenylsilylene group and the like.
In some of the embodiments, the number of carbon atoms of the alkylene group is an integer of 1 to 5; further, the alkylene group has 2 or 3 carbon atoms and is an ethylene group or a propylene group.
In some embodiments, the silylene group is a silylene group substituted with an alkyl group or an aryl group on a silicon atom, wherein the number of carbon atoms of the substituent group may be an integer between 1 and 12; further, the substituent is an alkyl group or a phenyl group.
In some embodiments herein, the homopolymer is selected from at least one of polyethylene oxide (PEO), polypropylene oxide (PPO), and Polyorganosiloxane (PSi).
In some embodiments of the present application, the homopolymer has a molecular weight of 500 to 10000000.
In some embodiments of the present application, the negative electrode slurry includes 0.01 to 5 parts by mass of the polymer ion conductor based on 100 parts by mass of the negative electrode active material. The content of the polymer ion conductor in the negative electrode slurry is not too small or too large. When the addition amount of the polymer ion conductor is less than 0.01 part by mass, the improvement on the ion conductivity, rate capability and high-temperature cycle performance of the prepared negative plate is not obvious; when the amount of the polymer ion conductor added is more than 5 parts by mass, the energy density of the finally obtained battery is limited. Therefore, the amount of the additive is controlled to 0.01 to 5 parts by mass.
In some embodiments of the present application, the negative active material includes, but is not limited to, carbon materials, non-limiting examples of which include materials such as natural graphite, artificial graphite, expanded graphite, carbon black, carbon nanotubes, activated carbon, carbon fibers, mesophase micro carbon sphere (MCMB) fullerenes, and the like; silicon materials, non-limiting examples of which include materials such as crystalline silicon, amorphous silicon, microcrystalline silicon, silicon oxygen composites, silicon carbon composites, and the like; metals capable of alloying with lithium and their compounds/alloys, non-limiting examples of which include metallic elements such as Al, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt, Ti, and the like, and non-limiting examples of compounds/alloys thereof include Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, and the like2Spinel-structured lithiated TiO2-Li4Ti5O12Li-Al alloy; others include, for example, lithium-containing nitrides and the like.
In some embodiments of the present application, the negative electrode paste further includes at least one of a binder and a conductive agent.
In order to tightly bind the negative active material to the current collector and to uniformly disperse the negative active material to form a good electron and ion conductive network, it is necessary to add a binder to the negative electrode slurry. Non-limiting examples of binders include polyacrylic acid (salt, ester), polyacrylonitrile, polyimide, polyvinyl alcohol, polyvinylidene fluoride, polyvinyl ether, styrene butadiene rubber, sodium carboxymethyl cellulose, sodium alginate, chitosan, guar gum, lignin, sericin, and the like. In addition, the addition of the conductive agent can improve the collection of micro-current between the negative active material and the current collector, and ensure that the negative electrode has good charge and discharge performance. The conductive agent is any conductive material that can be used for manufacturing an electrode, and is only required to satisfy the requirement of not causing chemical changes in the battery, and non-limiting examples thereof include conductive carbon black Super-P, natural graphite, artificial graphite, acetylene black, ketjen black, carbon nanotubes, graphene, graphdine, carbon fibers, and the like.
In some embodiments of the present application, the anode slurry may further include other additives such as a stabilizer, a flame retardant, a lubricant, an antioxidant, a plasticizer, a dispersant, an antistatic agent, and the like.
In addition, the negative electrode slurry may be prepared by dispersing the above-mentioned raw materials such as the negative electrode active material, the polymer ion conductor, and the like, with an aqueous dispersion medium such as water, a lower alcohol, a lower ketone, or a nonaqueous dispersion medium such as N-methylpyrrolidone.
In a second aspect of the present application, there is provided a negative electrode sheet comprising a current collector and a negative electrode active material layer on the current collector, the negative electrode active material layer being made of the negative electrode slurry described above.
Among them, the current collector material is arbitrarily selected from materials capable of increasing conductivity without causing chemical changes of the battery, and non-limiting examples thereof include copper, stainless steel, aluminum, nickel, titanium, aluminum-cadmium alloy, and the aforementioned materials subjected to surface treatment. Meanwhile, the current collector material may be used in the form of, for example, a film, a sheet, a foil, a net, a porous structure, a foam, a non-woven fabric, and the like. The manner of forming the anode active material layer from the anode slurry may be any process well known in the art, and specifically, a method such as direct coating and baking may be employed, and the specific manner of coating includes spin coating, spray coating, and the like.
In a third aspect of the present application, a lithium ion battery is provided, and the lithium ion battery includes the above negative electrode sheet.
In some embodiments of the present application, the lithium ion battery is any one of a lithium ion secondary battery and a lithium polymer secondary battery.
The lithium ion battery is characterized in that a positive plate and a negative plate are mutually separated by a diaphragm, and ions are transported and current is conducted through electrolyte so as to realize repeated charging and discharging processes. The lithium ion secondary battery refers to a lithium ion battery in which an electrolyte exists in the form of a liquid solution, and the lithium polymer secondary battery refers to a lithium ion battery in which an electrolyte exists in the form of a high molecular polymer.
The positive electrode sheet also includes a positive electrode current collector and a positive electrode active material layer made of a positive electrode slurry including a positive electrode active material, similarly to the negative electrode sheet, and the positive electrode slurry may further contain other additives such as a positive electrode binder and a positive electrode conductive agent, as necessary. The selection of the materials of the positive electrode current collector, the positive electrode binder and the positive electrode conductive agent can refer to the relevant materials of the corresponding negative electrode sheet, or other common materials well known in the art can be adopted.
In some embodiments of the present application, to achieve higher energy density, the positive electrode active material is typically a lithium-containing compound. Non-limiting examples of the lithium-containing compound include lithium transition metal complex oxides, lithium transition metal phosphate compounds, and the like. Wherein the lithium transition metal composite oxide is an oxide containing lithium and one or more transition metal elements as constituent elements. The lithium transition metal phosphate compound is a phosphate compound containing lithium and one or more transition metal elements as constituent elements.
The chemical formulas of the lithium transition metal composite oxide and the lithium transition metal phosphate compound are respectively LiaM1O2Or LibM2PO4. In the formula, M1And M2Respectively, one or more transition metal elements such as Co, Ni, Mn, Fe. The values of a and b vary depending on the charge-discharge state, and are generally in the ranges of 0.05. ltoreq. a.ltoreq.1.10 and 0.05. ltoreq. b.ltoreq.1.10.
Further, non-limiting examples of the lithium transition metal composite oxide include LiCoO2、LiNiO2And LiNi1-x-yMn(Al)xCoyO2(in the formula 0)<x+y<1, and 0<x<1、0<y<1) And the like. Non-limiting examples of lithium transition metal phosphate compounds include LiFePO4、LiCoPO4、LiFe1-uMnuPO4(in the formula 0)<u<1). When the above compound is selected as the positive electrode active material, a high battery capacity and excellent cycle characteristics can be obtained for the battery.
In some embodiments of the present application, the surface of the positive electrode active material layer is provided with a coating layer, or the positive electrode slurry may be mixed with another compound having a coating layer. The coating can be prepared from at least one of an oxide, hydroxide, oxyhydroxide, carbonate, hydroxycarbonate of the coating element. The coating element may be selected from at least one of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr.
In some embodiments of the present application, the separator may be any material capable of separating the positive electrode sheet and the negative electrode sheet and having lithium ion permeability and electronic insulation, such as polyethylene, polypropylene, polyethylene terephthalate, polyimide, aramid, and the like. Among them, polyethylene and polypropylene have a good effect of preventing short circuits, and the stability of the battery can be improved by the shutdown effect. Further, the polyethylene may be at least one of high density polyethylene, low density polyethylene, and ultra high molecular weight polyethylene.
In some embodiments of the present application, at least one surface of the separator is provided with a porous layer. The porous layer can improve the heat resistance, the oxidation resistance and the electrolyte infiltration performance of the diaphragm and enhance the adhesion between the diaphragm and the pole piece.
In some embodiments of the present application, the porous layer comprises inorganic particles and a binder. Non-limiting examples of inorganic particles include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, cerium oxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium sulfate, and the like. Non-limiting examples of binders include polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and the like.
In some embodiments of the present application, the lithium ion battery is a lithium ion secondary battery, which further includes a positive electrode sheet, an electrolyte, and a separator.
In some embodiments of the present application, the electrolyte includes an organic solvent and a lithium salt, and further includes additives such as a film forming additive, an overcharge protection additive, and the like.
The organic solvent may be a cyclic carbonate, a linear carbonate, a carboxylic ester, or the like. Among them, the cyclic carbonate may be, for example, Ethylene Carbonate (EC), Propylene Carbonate (PC), etc., the linear carbonate may be, for example, dimethyl carbonate (DMC), Ethyl Methyl Carbonate (EMC), diethyl carbonate (DEC), etc., and the carboxylic acid ester may be, for example, Propyl Propionate (PP), Ethyl Propionate (EP), Methyl Propionate (MP), etc.
Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPF)6) Lithium perchlorate (LiClO)4) Lithium hexafluoroarsenate (LiAsF)6) Lithium bis (fluorosulfonyl) imide (LiFSI), lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), and the like.
Non-limiting examples of additives include fluoroethylene carbonate (FEC), Vinylene Carbonate (VC), Vinyl Ethylene Carbonate (VEC), 1, 3-Propane Sultone (PS), Hexanetricarbonitrile (HTCN), and the like.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
Fig. 1 is a photograph of the morphology of a negative electrode sheet produced from the negative electrode slurry of example 5 of the present application.
Fig. 2 is a photograph of the morphology of a negative electrode sheet prepared from the negative electrode slurry of comparative example 1 of the present application.
Detailed Description
The conception and the resulting technical effects of the present application will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all embodiments, and other embodiments obtained by those skilled in the art without inventive efforts based on the embodiments of the present application belong to the protection scope of the present application.
The following detailed description of embodiments of the present application is provided for the purpose of illustration only and is not intended to be construed as a limitation of the application.
In the description of the present application, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present number, and the above, below, within, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present application, unless otherwise expressly limited, terms such as set, mounted, connected and the like should be construed broadly, and those skilled in the art can reasonably determine the specific meaning of the terms in the present application by combining the detailed contents of the technical solutions.
In the description of the present application, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Example 1
The present example provides a negative electrode slurry including graphite and SiO used as negative electrode active materialsm(0<m<2) The conductive carbon black Super P used as a conductive agent, the sodium carboxymethyl cellulose and the styrene-butadiene rubber used as a binder, the polymer ion conductor and a proper amount of water, wherein the polymer ion conductor in the embodiment is selected from polyorganosiloxane, the chemical formula of which is shown in the specification, and the molecular weight of the polyorganosiloxane is 500-107：
Wherein, in the negative active material, the content of graphite is 85 percent and SiO ismThe content of (A) is 15%;
in the negative electrode slurry, negative electrode active material: conductive agent: sodium carboxymethylcellulose: styrene-butadiene rubber: the mass ratio of the polyorganosiloxane is 90: 4: 2: 4: 0.475. that is, the amount of the polyorganosiloxane added was 0.5% by mass of the negative electrode active material.
The present embodiment also provides a lithium ion secondary battery, which is prepared by the following steps:
1. preparation of the negative electrode
Uniformly mixing the raw materials in a vacuum stirrer according to the proportion to obtain cathode slurry with the solid content of 50 wt%; and uniformly coating the negative electrode slurry on a copper foil of a negative current collector, and drying to obtain a negative plate.
2. Preparation of the Positive electrode
LiNi serving as a positive electrode active material0.8Co0.15Al0.05O2(NCA), a conductive agent Super P, a binder polyvinylidene fluoride according to a weight ratio of 96: 2: 2, mixing, adding a proper amount of dispersion medium N-methyl pyrrolidone, and uniformly stirring under the action of a vacuum stirrer to obtain anode slurry with the solid content of 70 wt%; and (3) uniformly coating the positive slurry on a positive current collector aluminum foil, and drying to obtain the positive plate.
3. Preparation of the electrolyte
In a dry argon atmosphere glove box, organic solvents of ethylene carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate are added according to the weight ratio of 25: 10: 20: 45, followed by the addition of additives: 1, 3-propane sultone (2 wt%), vinylene carbonate (0.5 wt%), fluoroethylene carbonate (8 wt%), dissolved and fully stirred, and added with lithium salt LiPF with final concentration of 1.1mol/L6And mixing uniformly to obtain the electrolyte.
4. Preparation of lithium ion secondary battery
A 15 μm thick polyethylene separator was used. And sequentially stacking the positive plate, the diaphragm and the negative plate to enable the isolating film to be positioned between the positive plate and the negative plate to play an isolating role, then winding and welding the tabs, then placing the tabs into an outer packaging foil aluminum-plastic film, drying, injecting prepared electrolyte, and carrying out vacuum packaging, standing, formation, shaping, capacity test and other procedures to obtain the lithium ion secondary battery.
Example 2
This example provides a negative electrode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polypropylene oxide.
Example 3
This example provides an anode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyethylene oxide, and the amount of polyethylene oxide added is 0.01% by mass of the anode active material.
Example 4
This example provides an anode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyethylene oxide, and the amount of polyethylene oxide added is 0.1% by mass of the anode active material.
Example 5
This example provides an anode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyethylene oxide, and the amount of polyethylene oxide added is 0.5% by mass of the anode active material.
Example 6
This example provides an anode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyethylene oxide, and the amount of polyethylene oxide added is 1% by mass of the anode active material.
Example 7
This example provides an anode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyethylene oxide, and the amount of polyethylene oxide added is 5% by mass of the anode active material.
Performance test
Comparative example 1
This example provides a negative electrode paste, which is different from example 1 in that no polymer ion conductor is added.
Comparative example 2
This example provides a negative electrode slurry, which differs from example 1 in that the polyorganosiloxane is replaced with polyoxyethylene-b-polystyrene.
And (3) preparing a negative plate from the negative electrode slurry of the examples 1-7 and the negative electrode slurry of the comparative examples 1-2 according to the method in the example 1, and further assembling to obtain the lithium ion battery. The prepared lithium ion battery is taken to carry out rate performance, normal temperature and high temperature cycle performance tests, and the specific method comprises the following steps:
test of ordinary temperature cycle Performance
And (3) placing the lithium ion battery in a constant temperature box at 25 ℃, and standing for 30 minutes to keep the temperature of the lithium ion battery constant. The lithium ion battery, which reached a constant temperature, was charged at a constant current of 0.5C (25 ℃) to a voltage of 4.2V, then charged at a constant voltage of 4.2V to a current of 0.05C, and then discharged at a constant current of 0.5C (25 ℃) to a voltage of 2.75V, which was a charge-discharge cycle, and its initial capacity was recorded. After repeating 300 cycles, the discharge capacity was recorded. The ratio of the discharge capacity to the initial capacity is a capacity retention rate at a normal temperature cycle.
Rate capability test
And (3) placing the lithium ion battery in a constant temperature box at 25 ℃, and standing for 30 minutes to keep the temperature of the lithium ion battery constant. The lithium ion battery which reached a constant temperature was charged at a constant current of 0.5C (25 ℃) to a voltage of 4.2V, then charged at a constant voltage of 4.2V to a current of 0.05V, and then discharged at a constant current of 0.5C (25 ℃) to a voltage of 2.75V, and its 0.5C discharge capacity was recorded. The lithium ion battery, which reached a constant temperature, was charged at a constant current of 0.5C (25 ℃) to a voltage of 4.2V, then charged at a constant voltage of 4.2V to a current of 0.05C, and then discharged at a constant current of 3C (25 ℃) to a voltage of 2.75V, and the 3C discharge capacity was recorded. The ratio of the 3C discharge capacity to the 0.5C discharge capacity is the rate discharge capacity retention rate.
High temperature cycle performance test
And (3) placing the lithium ion battery in a constant temperature box at 45 ℃, and standing for 30 minutes to keep the temperature of the lithium ion battery constant. The lithium ion battery, which reached a constant temperature, was charged at a constant current of 1C (45 ℃) to a voltage of 4.2V, then charged at a constant voltage of 4.2V to a current of 0.05C, and then discharged at a constant current of 1C (45 ℃) to a voltage of 2.75V, which is a charge-discharge cycle, and its initial capacity was recorded. After repeating 100 cycles, the discharge capacity was recorded. The ratio of the discharge capacity to the initial capacity is the capacity retention rate at high temperature cycles.
The test results are shown in table 1:
TABLE 1 Performance test results
The appearances of the negative electrode sheets of the embodiment 5 and the comparative example 1 are respectively shown in fig. 1 and fig. 2, and it can be seen from the experimental results of fig. 1 and fig. 2 in combination with table 1 that the negative electrode sheet without the polymer ion conductor introduced has an obvious cracking phenomenon after coating is completed, and the viscosity increase brought by the embodiment after the polymer ion conductor is introduced enables the negative electrode active material and the like in the negative electrode slurry to be more uniformly and tightly bonded to the current collector, thereby effectively avoiding the occurrence of the cracking phenomenon and the like.
Comparing the battery performance data of the above example and comparative example 1, it can be seen that the rate performance, the normal temperature cycle performance and the high temperature cycle performance of the example are all significantly improved after the polymer ion conductor is introduced. Further comparing the data of the rate discharge and the normal temperature cycle performance of the examples 1, 2, 5 and the comparative examples 1, 2, it can be seen that when the added polymer ion conductor is a block copolymer, the rate performance and the normal temperature cycle performance of the battery are improved to some extent, but the performance improvement is obviously much worse than that brought by adding the polymer ion conductor selected from the oxygen-containing group homopolymer in the examples. In contrast, the high-temperature cycle performance data of comparative examples 1, 2, and 5 and comparative examples 1 and 2 show that the high-temperature cycle performance of the battery is not significantly improved when the polymer ion conductor is a block copolymer, while the high-temperature cycle capacity retention rate is significantly improved when the oxygen-containing group homopolymer in the embodiment of the present application is selected. This is obviously an effect improvement unique to the embodiments of the present application.
The present application has been described in detail with reference to the embodiments, but the present application is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present application. Furthermore, the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
Claims (10)
1. An anode slurry comprising an anode active material and a polymer ion conductor comprising a homopolymer formed from an oxygen-containing monomer.
2. The negative electrode slurry according to claim 1, wherein the homopolymer is a compound represented by formula (i):
wherein R is1Is an optional alkylene or silylene group, and n is an integer of 10 to 250000.
3. The negative electrode slurry according to claim 1, wherein the homopolymer is at least one selected from the group consisting of polyethylene oxide, polypropylene oxide, and polyorganosiloxane.
4. The negative electrode slurry according to claim 1, wherein the homopolymer has a molecular weight of 500 to 10000000.
5. The negative electrode slurry according to any one of claims 1 to 4, wherein the negative electrode slurry contains the polymer ion conductor in an amount of 0.01 to 5 parts by mass based on 100 parts by mass of the negative electrode active material.
6. The negative electrode paste according to any one of claims 1 to 4, wherein the negative electrode paste further comprises at least one of a binder and a conductive agent.
7. A negative electrode sheet comprising a current collector and a negative electrode active material layer on the current collector, the negative electrode active material layer being made of the negative electrode slurry according to any one of claims 1 to 6.
8. A lithium ion battery comprising the negative electrode sheet according to claim 7.
9. The lithium ion battery according to claim 8, wherein the lithium ion battery is any one of a lithium ion secondary battery and a lithium polymer secondary battery.
10. The lithium ion battery according to claim 9, wherein the lithium ion battery is a lithium ion secondary battery further comprising a positive electrode sheet, an electrolyte, and a separator.
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| CN202110210597.2A CN113013412A (en) | 2021-02-25 | 2021-02-25 | Negative electrode slurry, negative electrode sheet and lithium ion battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114050260A (en) * | 2021-10-22 | 2022-02-15 | 深圳市研一新材料有限责任公司 | Positive electrode film additive composition, positive electrode film additive, positive electrode plate and secondary battery |
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| CN101760154A (en) * | 2009-11-09 | 2010-06-30 | 南京双登科技发展研究院有限公司 | Binding agent for super capacitor electrode paste |
| CN106654276A (en) * | 2016-11-22 | 2017-05-10 | 上海空间电源研究所 | Preparation method of solid-state lithium ion battery electrode taking PEO (Polyethylene Oxide) as binding agent |
| CN108232156A (en) * | 2018-01-03 | 2018-06-29 | 清陶（昆山）能源发展有限公司 | A kind of silicon-carbon composite cathode of solid state battery and preparation method thereof |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101760154A (en) * | 2009-11-09 | 2010-06-30 | 南京双登科技发展研究院有限公司 | Binding agent for super capacitor electrode paste |
| CN106654276A (en) * | 2016-11-22 | 2017-05-10 | 上海空间电源研究所 | Preparation method of solid-state lithium ion battery electrode taking PEO (Polyethylene Oxide) as binding agent |
| CN108232156A (en) * | 2018-01-03 | 2018-06-29 | 清陶（昆山）能源发展有限公司 | A kind of silicon-carbon composite cathode of solid state battery and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114050260A (en) * | 2021-10-22 | 2022-02-15 | 深圳市研一新材料有限责任公司 | Positive electrode film additive composition, positive electrode film additive, positive electrode plate and secondary battery |
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