Ionic conductive colloid with core-shell structure, preparation method of ionic conductive colloid and application of ionic conductive colloid in battery
By using core-shell structured ion-conducting colloids in lithium-ion and lithium-sulfur batteries, the problem of poor wettability at the interface between graphite anode and electrolyte was solved, enabling fast charging and improved charge-discharge performance of the batteries.
Patent Information
- Application Number
- CN202410638653.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-22
- Publication Date
- 2025-11-25
AI Technical Summary
The poor wettability of the graphite anode and electrolyte interface in existing lithium-ion and lithium-sulfur batteries results in poor electrochemical reaction kinetics, which limits the battery's fast-charging performance.
A core-shell structured ion-conducting colloid is adopted, with the core being styrene-butadiene rubber and the shell being a polymer formed by the polymerization of organic sulfonate monomers, nitrile monomers and acrylate monomers, forming a soft core and hard shell structure to enhance the interfacial compatibility between the electrode and the electrolyte.
It improves the electrode's ability to absorb and retain electrolyte, enhances ion conduction performance, reduces battery electrochemical polarization, and enables fast charging and improved charge-discharge cycle performance.
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Figure CN121005833A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of core-shell structure ion conductive colloidal and its preparation method and application in battery, belong to battery technical field. BACKGROUND
[0002] Electric vehicles develop rapidly and popularize in market, in addition to the battery with higher requirements of high energy density, high safety performance and long cycle life, also expect the battery to have fast charging performance, shorten the charging time, to meet the requirement of people travel.
[0003] Battery performance, especially the fast charge-discharge performance of battery is closely related to electrode electrochemical reaction kinetics performance, electrode material, composition, microstructure and material surface interface characteristics determine the electrochemical reaction kinetics performance of electrode.Lithium ion battery is composed of positive electrode, negative electrode, separator and non-aqueous electrolyte.Current commercial lithium ion battery mainly uses lithium cobaltate, nickel-manganese-cobalt lithium ternary material and lithium iron phosphate as positive material;Artificial graphite or natural graphite as negative material.According to the physical and chemical properties of positive and negative materials, and the wettability of material surface interface and electrolyte, the electrochemical reaction kinetics of graphite negative electrode in lithium ion battery is the main factor affecting the battery performance.
[0004] As we all know, graphite is a kind of non-polar substance with strong hydrophobicity.The battery electrolyte is composed of high dielectric constant organic solvent and LiPF6, which belongs to strong polar liquid.The non-polar characteristics of graphite and the strong polar characteristics of electrolyte lead to poor wettability of graphite negative electrode and electrolyte interface in battery.In addition, the adhesives used in graphite negative electrode are mainly polyacrylic acid copolymer PAA and styrene-butadiene emulsion SBR.PAA and SBR belong to non-ion conductive material, which can provide adhesion to graphite powder while shielding part of the surface area of graphite particles, reducing the effective surface area participating in electrochemical reaction.The poor wettability of electrolyte interface of graphite electrode and non-ion conductive PAA and SBR adhesive are the causes of poor electrochemical reaction kinetics performance of graphite negative electrode.
[0005] In addition, the sulfur electrode of lithium-sulfur battery is also non-polar and has strong hydrophobicity, which is incompatible with electrolyte, like graphite electrode, resulting in poor electrochemical reaction kinetics performance of lithium-sulfur battery.
[0006] Overcoming the above technical problems of graphite negative electrode or sulfur electrode to achieve fast charging has very wide market application value, however, there is no method that can overcome the above technical problems to achieve fast charging at present. SUMMARY
[0007] The first object of the present application is to provide a kind of core-shell structure ion conductive colloidal.
[0008] To achieve the first object of the present application, the core of the core-shell structure ion conductive colloid is styrene-butadiene rubber, and the shell is a polymer after polymerization of organic sulfonate monomers, nitrile monomers and acrylic monomers; the D50 particle size of the core-shell structure ion conductive colloid is in the range of 0.1-2.0 μm.
[0009] The core-shell structure colloid of the present application is a hard-shell soft-core colloidal particle, which maintains the spherical structure of the colloidal particle whether in film formation or in electrolyte immersion.
[0010] In a specific embodiment, the core-shell structure ion conductive colloid is immersed in electrolyte at 50°C for 48 hours, the electrolyte absorption rate of the gel film is ≤100%, and the ion conductivity of the gel film after absorbing electrolyte is 10 -5 ~10 -3 Scm -1 .
[0011] In a specific embodiment, the organic sulfonate monomers include any one or a mixture of more than one of sodium vinyl sulfonate, sodium allyl sulfonate, sodium methacryl sulfonate, 2-acrylamido-2-methylpropane sulfonic acid and sodium styrene sulfonate, and preferably include 2-acrylamido-2-methylpropane sulfonic acid monomers.
[0012] In a specific embodiment, the nitrile monomers include at least one of acrylonitrile, methacrylonitrile, allyl cyanide, 2-methyl-3-butenenitrile and N,N-diethyl cyanoacrylamide monomers, and preferably include N,N-diethyl cyanoacrylamide monomers.
[0013] In a specific embodiment, the acrylic monomers include at least one of the chemical formula CH2=CR1COOR2, wherein R1 is -H or -CH3, R2 is -(CH2) n CH3, and n is an integer in the range of 0-12; preferably, the acrylic monomers include at least one of methyl acrylate MA, ethyl acrylate EA, propyl acrylate PA, butyl acrylate BA, vinyl acetate VAC and ethylhexyl acrylate EHA.
[0014] In a specific embodiment, the mass ratio of the core-shell structure ion conductive colloid, the organic sulfonate monomers, the nitrile monomers and the acrylic monomers is 100:3-15:5-30:0-20; preferably, the mass ratio is 100:5-8:20-25:8-15; and more preferably, the mass ratio is 100:5-8:20-25:8-12.
[0015] The second object of the present application is to provide a preparation method of a core-shell structure ion conductive colloid.
[0016] To achieve the second object of the present application, the preparation method of the core-shell structure ion conductive colloid includes:
[0017] a. mixing the styrene butadiene rubber emulsion with deionized water, organic sulfonate monomer, nitrile monomer and acrylic ester monomer to obtain a mixed solution; preferably, the styrene butadiene rubber emulsion is first mixed with deionized water to obtain solution A, and then the organic sulfonate monomer, nitrile monomer and acrylic ester monomer are mixed with solution A to obtain the mixed solution;
[0018] b. heating the mixed solution of step a to 50-75℃, adding a water-soluble initiator to initiate polymerization for 6-48 hours; after the reaction is completed, adjusting the pH of the product to 6.5-7.5 with lye to obtain a core-shell structure colloidal emulsion; the water-soluble initiator is preferably ammonium persulfate.
[0019] The styrene butadiene rubber emulsion SBR in the preparation method is not particularly limited, and commercially available styrene butadiene rubber emulsion SBR with a solid content of 40-50% can be used.
[0020] In a specific embodiment, the amount of the organic sulfonate monomer is 3wt%-15wt% of the solid mass of the core-shell structure colloidal emulsion, preferably 5wt%-15wt%;
[0021] The amount of the nitrile monomer is preferably 5wt%-30wt% of the solid mass of the core-shell structure colloidal emulsion;
[0022] The amount of the acrylic ester monomer is preferably 0-20wt% of the solid mass of the core-shell structure colloidal emulsion.
[0023] In a specific embodiment, the content of nitrogen in the solid mass of the core-shell structure colloidal emulsion of step c is 1.0wt%-10.0wt%, and the solid content of the colloidal emulsion is 20wt%-45wt%.
[0024] A third object of the present application is to provide a core-shell structure ion conductive colloid or a preparation method of the core-shell structure ion conductive colloid, and the application of the core-shell structure ion conductive colloid in a battery.
[0025] To achieve the third object of the present application, the battery is a lithium ion battery or a sodium-lithium battery, or a sulfur-lithium battery.
[0026] Advantages:
[0027] The core-shell structure ion conductive colloid of the present application is a core-shell structure colloid with a soft core and a hard shell, and the surface of the colloid is rich in ionized sulfonate and lithium ions. Under the action of the electrostatic field on the surface of the colloid, the core-shell structure colloid still maintains the spherical structure after film formation, and the gel film still maintains the spherical structure of the core-shell structure colloid after being soaked in an electrolyte at 50℃ for 96 hours. This feature can ensure the stability of the structure of the core-shell structure colloid in the battery electrode.
[0028] The core-shell structure ion conductive colloid of the present application is used as an additive for enhancing the absorption and storage of electrolyte and ion conduction of negative electrode sheet, which can improve the electrolyte absorption and retention capacity of the electrode, enhance the ion transport performance of the electrode active material, reduce the electrochemical polarization of the battery, and thus improve the rate charge-discharge, low-temperature charge-discharge and charge-discharge cycle performance of the battery, and achieve fast charging. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 Figure is the colloidal emulsion particle size distribution test chart of Example 5.
[0030] Figure 2 Figure is the scanning electron microscope chart of the film formed by the core-shell structure colloid of Example 5 under the action of the electrostatic field on the surface of the colloid.
[0031] Figure 3 Figure is the scanning electron microscope chart of the film of Example 5 after being soaked in electrolyte at 50℃ for 96 hours. DETAILED DESCRIPTION
[0032] To achieve the first object of the present application, the core of the core-shell structure ion conductive colloid is styrene-butadiene rubber, and the shell is a polymer after the polymerization of organic sulfonate monomers, nitrile monomers and acrylate monomers; the D50 particle size of the core-shell structure ion conductive colloid is in the range of 0.1-2.0 μm.
[0033] The core-shell structure colloid of the present application is a soft core and hard shell colloidal particle, which still maintains the spherical structure of the colloidal particle whether it is film formation or film soaking in electrolyte.
[0034] In a specific embodiment, the core-shell structure ion conductive colloid is soaked in electrolyte at 50℃ for 48 hours, the liquid absorption rate of the film is ≤100%, and the ion conductivity of the film after absorbing electrolyte is 10 -5 ~10 -3 Scm -1 .
[0035] In a specific embodiment, the organic sulfonate monomers include any one or more of sodium vinyl sulfonate, sodium allyl sulfonate, sodium methacryl sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, and sodium styrene sulfonate, preferably including 2-acrylamido-2-methylpropane sulfonic acid monomer.
[0036] In a specific embodiment, the nitrile monomers include at least one of acrylonitrile, methacrylonitrile, allyl cyanide, 2-methyl-3-butenenitrile, and N,N-diethyl cyanoacrylamide monomers, preferably including N,N-diethyl cyanoacrylamide monomer.
[0037] In one embodiment, the acrylate monomer includes at least one of the chemical formula CH2=CR1COOR2, wherein R1 is -H or -CH3, R2 is -(CH2)nCH3, and n is an integer from 0 to 12. n Preferably, the acrylate monomer includes at least one of methyl acrylate (MA), ethyl acrylate (EA), propyl acrylate (PA), butyl acrylate (BA), vinyl acetate (VAC), and ethylhexyl acrylate (EHA).
[0038] In one embodiment, the mass ratio of the core-shell ion conductive colloid, the organic sulfonate monomer, the nitrile monomer, and the acrylate monomer is 100:3-15:5-30:0-20; preferably 100:5-8:20-25:8-15; and more preferably 100:5-8:20-25:8-12.
[0039] To achieve the second object of the present application, the preparation method of the core-shell ion conductive colloid includes:
[0040] a. mixing the styrene-butadiene rubber emulsion, deionized water, the organic sulfonate monomer, the nitrile monomer, and the acrylate monomer to obtain a mixed solution; preferably, first mixing the styrene-butadiene rubber emulsion and the deionized water to obtain solution A, and then mixing the organic sulfonate monomer, the nitrile monomer, and the acrylate monomer with solution A to obtain the mixed solution;
[0041] b. heating the mixed solution of step a to 50-75°C, adding a water-soluble initiator to initiate polymerization for 6-48 hours; adjusting the pH of the product to 6.5-7.5 with lye after the reaction is completed to obtain the core-shell colloidal emulsion; and the water-soluble initiator is preferably ammonium persulfate.
[0042] In the preparation method, the styrene-butadiene rubber emulsion SBR is not particularly limited, and commercially available styrene-butadiene rubber emulsion SBR can be used, with a solid content of 40-50%.
[0043] In one embodiment, the amount of the organic sulfonate monomer is 3wt%-15wt% of the solid content of the core-shell colloidal emulsion, preferably 5wt%-15wt%.
[0044] The amount of the nitrile monomer is preferably 5wt%-30wt% of the solid content of the core-shell colloidal emulsion.
[0045] The amount of the acrylate monomer is preferably 0-20wt% of the solid content of the core-shell colloidal emulsion.
[0046] In one specific embodiment, the content of nitrogen in the solid mass of the core-shell structure colloidal emulsion of step c is 1.0wt% to 10.0wt%, and the content of the solid mass of the colloidal emulsion is 20wt% to 45wt%.
[0047] A third object of the present application is to provide the above-mentioned core-shell structure ion-conducting colloidal, the preparation method of the above-mentioned core-shell structure ion-conducting colloidal, and the application of the core-shell structure ion-conducting colloidal in batteries.
[0048] To achieve the third object of the present application, the battery is a lithium ion battery or a sodium-lithium battery, or a sulfur-lithium battery.
[0049] The specific embodiments of the present application are further described below in conjunction with examples, and the present application is not limited in the scope of the described examples.
[0050] The method for measuring the liquid absorption rate of the core-shell structure gel film is as follows: the colloidal emulsion is poured into a plastic container, and the water is first dried in an air oven at 80-90℃, and then transferred to a vacuum oven for vacuum drying at 85-90℃ for 48 hours. The sample after vacuum drying is weighed, and then immersed in an electrolyte, and the sample is soaked at 50℃ for 48 hours, and then weighed again. The liquid absorption rate of the sample is:
[0051] The liquid absorption rate % = (the weight after soaking - the weight before soaking) / the weight before soaking x 100%.
[0052] The method for measuring the conductivity of the core-shell structure gel film is as follows: the colloidal emulsion is poured into a plastic container, and the water is first dried in an air oven at 80-90℃, and then transferred to a vacuum oven for vacuum drying at 85-90℃ for 48 hours. The sample after vacuum drying is soaked in an electrolyte at 50℃ for 48 hours, and then taken out to absorb the electrolyte, and the ion conductivity of the gel film is measured using a resistance bridge instrument. The conductivity test conditions are as follows: frequency 20 kilohertz, and level 100 millivolts.
[0053] The colloidal emulsion particle size distribution, scanning electron microscope, and battery performance of the core-shell structure gel film of the present application are tested and characterized according to the test methods familiar to those skilled in the art.
[0054] Example 1
[0055] Into a glass reaction flask equipped with stirring, heating and condensing devices, 210 g of SBR emulsion with solid content of 50% and 230 g of deionized water were added, then 8.0 g of 2-acrylamido-2-methylpropanesulfonic acid monomer was added, 1.7 g of LiOH was added to neutralize the sulfonic acid monomer, and finally 35 g of acrylonitrile monomer was added. The reaction flask was heated under stirring, and after the temperature reached 55°C, 4 g of 10% ammonium persulfate aqueous solution was added to initiate polymerization, and the temperature was kept constant for 36 hr. After the reaction was completed, the pH of the product was adjusted to 6.5-7.5 with a small amount of LiOH aqueous solution, and a core-shell structure colloidal emulsion with a solid content of about 30% was obtained. The colloidal particle size D50 of the colloidal emulsion of this example is shown in Table 1.
[0056] 5 g of the core-shell structure colloidal emulsion was weighed into a plastic container, the water was dried in an air oven at 80-90°C, then transferred to a vacuum oven and dried at 85-90°C for 48 hr, and then the sample with a thickness of about 0.2 mm was immersed in the electrolyte solution commonly used in lithium ion batteries, and the electrolyte absorption rate and conductivity of the colloidal film were measured after immersion in the electrolyte solution at 50°C for 48 hr, and the results are shown in Table 1.
[0057] The electrolyte absorption rate of the core-shell structure colloidal film was measured as follows:
[0058] The vacuum-dried sample was weighed and immersed in the electrolyte solution commonly used in lithium ion batteries, and then taken out and weighed after immersion at 50°C for 48 hr. The sample absorption rate was:
[0059] The electrolyte absorption rate of the core-shell structure colloidal film was measured as follows:
[0060] The conductivity of the core-shell structure colloidal film was measured as follows: The colloidal film that had absorbed the electrolyte was measured for ionic conductivity using a resistance bridge instrument.
[0061] Example 2
[0062] The preparation method and composition ratio of the core-shell structure colloidal emulsion of this example were the same as those of Example 1, except that N,N-diethyl cyanoacrylamide monomer was used instead of acrylonitrile monomer, the reaction temperature was adjusted to 70°C, and the reaction time was shortened to 6 hr. The colloidal particle size D50, the electrolyte absorption rate and the conductivity of the colloidal film measured in this example are shown in Table 1.
[0063] Example 3
[0064] A glass reaction flask equipped with stirring, heating and condensing devices was charged with 200 g of SBR emulsion with solid content of 50%, 230 g of deionized water, 8.0 g of 2-acrylamido-2-methylpropanesulfonic acid monomer, 1.7 g of LiOH to neutralize the sulfonic acid monomer, 20 g of N,N-diethylcyanoacrylamide and 20 g of propylene isooctyl ester monomer. The reaction flask was heated under stirring until the temperature reached 70°C, 4 g of 10% ammonium persulfate aqueous solution was added to initiate polymerization, and the reaction was kept at constant temperature for 6 hours. After the reaction was completed, the pH of the product was adjusted to 6.5-7.5 with a small amount of LiOH aqueous solution, and a core-shell structure colloidal emulsion with solid content of about 30% was obtained. The colloidal particle size D50, liquid absorption rate and conductivity of the film measured in this example are shown in Table 1.
[0065] Example 4
[0066] The preparation method and components of the core-shell structure colloidal emulsion in this example were the same as in Example 3, except that the weight of N,N-diethylcyanoacrylamide and propylene isooctyl ester monomer was adjusted from 20 g:20 g to 28 g:12 g. The colloidal particle size D50, liquid absorption rate and conductivity of the film measured in this example are shown in Table 1.
[0067] Example 5
[0068] The preparation method and components of the core-shell structure colloidal emulsion in this example were the same as in Example 3, except that the weight of SBR emulsion, N,N-diethylcyanoacrylamide and propylene isooctyl ester monomer was adjusted from 200:20 g:20 g to 180:35 g:15 g. The colloidal particle size D50, liquid absorption rate and conductivity of the film measured in this example are shown in Table 1.
[0069] Example 6
[0070] The preparation method and components of the core-shell structure colloidal emulsion in this example were the same as in Example 5, except that sodium styrene sulfonate was used instead of lithium 2-acrylamido-2-methylpropanesulfonic acid monomer. The colloidal particle size D50, liquid absorption rate and conductivity of the film measured in this example are shown in Table 1.
[0071] Example 7
[0072] The preparation method and components of the core-shell structure colloidal emulsion in this example were the same as in Example 4, except that methyl acrylate was used instead of propylene isooctyl ester. The colloidal particle size D50, liquid absorption rate and conductivity of the film measured in this example are shown in Table 1.
[0073] Example 8
[0074] A glass reaction flask equipped with stirring, heating and condensing devices was charged with 184 g of SBR emulsion with solid content of 50%, 250 g of deionized water, 8.0 g of 2-acrylamido-2-methylpropanesulfonic acid monomer, 1.7 g of LiOH to neutralize the sulfonic acid monomer, 24 g of N,N-diethylcyanoacrylamide, 8 g of propyl isooctyl ester monomer and 16 g of methyl acrylate. The reaction flask was heated under stirring until the temperature reached 70°C, 4 g of 10% ammonium persulfate aqueous solution was added to initiate polymerization, and the reaction was kept at constant temperature for 6 hours. After the reaction was completed, the pH of the product was adjusted to 6.5-7.5 with a small amount of LiOH aqueous solution, and a core-shell structure colloidal emulsion with solid content of about 30% was obtained. The colloidal particle size D50, the liquid absorption rate and the conductivity of the film of the core-shell structure colloidal emulsion of the present example were measured, and the results are shown in Table 1.
[0075] Comparative Example 1
[0076] A commercially available SBR was measured for the emulsion particle size D50, the liquid absorption rate and the conductivity of the film under the same method and conditions, and the test results are shown in Table 1.
[0077] Table 1: Colloidal particle size D50, the liquid absorption rate and the conductivity of the film of the core-shell structure colloidal emulsion of the present example
[0078] Example Colloidal particle size D50 μm Electrolyte uptake % Conductivity Scm -1 ]] Example 1 0.832 96.4 1.2 x 10 -4 ]]> Example 2 0.341 87.2 9.7 x 10 -5 ]]> Example 3 0.187 55.3 1.1 x 10 -5 ]]> Example 4 0.186 66.5 3.1 x 10 -5 ]]> Example 5 0.188 72.5 7.4 x 10 -5 ]] Example 6 0.180 70.2 8.9 x 10 -5 ]] Example 7 1.634 69.7 1.6 x 10 -4 ]]> Example 8 1.483 86.9 2.7 x 10 -4 ]] Comparative Example 1 0.170 31.3 2.9 x 10 -8 ]]
[0079] Table 1 is the particle size D50, the liquid absorption rate and the conductivity of the film of the core-shell structure colloidal emulsion of the present example and the SBR of the comparative example. As can be seen from the table, the reactive monomer is polymerized in the SBR colloidal particle emulsion, and the D50 particle size of the reaction product is larger than the SBR colloidal seed particle size 0.170 μm, which conforms to the general rule of preparing a core-shell structure colloidal emulsion with polymer emulsion seed particles, and the typical feature of this core-shell colloidal preparation method is that the colloidal particle size becomes larger. In addition, the SBR emulsion film forming process will generally cause coagulation and demulsification, and the colloidal spherical structure is lost. The present application prepares a core-shell structure colloidal emulsion with soft core and hard shell, and the colloidal surface is rich in ionized sulfonate and lithium ions. Under the action of the electrostatic field on the colloidal surface, the core-shell structure colloidal film still maintains the spherical structure of the colloidal as shown in the scanning electron microscope photograph Figure 2 as shown in Figure 3 , and still maintains the core-shell structure colloidal spherical structure after the film is soaked in electrolyte at 50°C for 96 hours. This feature can ensure the stability of the structure of the core-shell structure colloidal in the battery electrode sheet.
[0080] Example 9
[0081] A negative electrode slurry was prepared by mixing 9.6 g of graphite, 0.1 g of conductive acetylene black, 0.15 g of ES218 aqueous binder, 0.05 g of carboxymethyl cellulose sodium, 0.10 g of the ion conductive gel of Example 3, and an appropriate amount of water. The slurry was uniformly coated on a copper foil, which was then dried at 120°C, rolled, and punched to form a circular electrode with a radius of 14 mm. The electrode was vacuum dried at 80°C for 16 h and then assembled into a Li / graphite electrode button cell with a lithium metal electrode in a dry argon glove box. The electrolyte was a commercially available electrolyte for lithium ion batteries, and the separator was a polypropylene microporous membrane.
[0082] The test conditions for the lithium insertion / extraction capacity of the button cell graphite electrode were as follows: the lithium extraction capacity was measured at a rate of 0.2 C, and the cutoff voltage was 1.5 V; the lithium insertion capacity was measured at a certain rate, followed by a 10 min rest, and then at a rate of 0.1 C, and the cutoff voltage was 0.05 V. The lithium insertion capacity at a certain rate / the total lithium insertion capacity of the graphite electrode was the lithium insertion ratio at a certain rate, and the test results are shown in Table 2.
[0083] Example 10
[0084] The graphite electrode composition, button cell preparation, and test conditions of this example were the same as those of Example 9, except that the ion conductive gel of Example 5 was used instead of the ion conductive gel of Example 3. The lithium insertion ratios of the graphite electrode at different rates measured in this example are shown in Table 2.
[0085] Comparative Example 2
[0086] The electrode composition, button cell preparation, and test conditions were the same as those of Example 9, except that there was no ion conductive gel component, and the amount of ES218 aqueous binder was adjusted to 0.25 g. The test results are shown in Table 2.
[0087] Table 2: Lithium insertion ratios of graphite electrodes at different rates
[0088] Example 0.2 C lithium insertion ratio % 0.5 C lithium insertion ratio % 1.0 C lithium insertion ratio % Example 9 98.3 89.0 53.9 Example 10 97.6 92.2 65.1 Comparative Example 2 97.1 79.6 38.9
[0089] Table 2 shows the lithium insertion ratios of the graphite electrodes of the button cells of Example 9, Example 10, and Comparative Example 2. The greater the lithium insertion ratio, the smaller the electrochemical polarization of the lithium insertion reaction of the electrode. The data in Table 2 show that the lithium insertion ratio of the graphite electrode containing the ion conductive gel is higher than that of the graphite electrode of the comparative example at rates of 0.5 C and 1.0 C, indicating that the ion conductive gel as an electrode component is beneficial to reducing the electrochemical polarization and improving the electrochemical reaction kinetics of the battery.
[0090] Example 11
[0091] A homogeneous slurry of sulfur electrode was prepared by mixing 9.0 g of 75% sulfur-carbon composite, 0.5 g of conductive acetylene black, 0.3 g of AM50 aqueous binder, and 0.2 g (as solid) of the ionically conductive gel of Example 5 with an appropriate amount of water. The slurry was uniformly coated on an aluminum foil, then dried at 80°C, rolled, and punched to make a circular electrode with a radius of 14 mm, and a sulfur loading of 2.45 mg / cm 2 The sulfur electrode was vacuum dried at 60°C for 48 hr, then assembled into a Li / sulfur button cell with lithium metal in a dry argon glove box. The electrolyte was a commercially available electrolyte for lithium-sulfur batteries, and the separator was a polypropylene microporous membrane. The lithium-sulfur battery was tested under the following conditions: galvanostatic charge-discharge at a current of 0.5 mA, and a charge-discharge cutoff voltage of 1.6-2.7 V.
[0092] Comparative Example 3
[0093] A homogeneous slurry of sulfur electrode was prepared by mixing 9.2 g of 75% sulfur-carbon composite, 0.5 g of conductive acetylene black, and 0.3 g of AM50 aqueous binder with an appropriate amount of water. The slurry was uniformly coated on an aluminum foil, then dried at 80°C, rolled, and punched to make a circular electrode with a radius of 14 mm, and a sulfur loading of 2.68 mg / cm 2 The sulfur electrode was vacuum dried at 60°C for 48 hr, then assembled into a Li / sulfur button cell with lithium metal in a dry argon glove box. The electrolyte was a commercially available electrolyte for lithium-sulfur batteries, and the separator was a polypropylene microporous membrane. The lithium-sulfur battery was tested under the following conditions: galvanostatic charge-discharge at a current of 0.5 mA, and a charge-discharge cutoff voltage of 1.6-2.7 V.
[0094] Table 3. Charge-discharge cycling data for lithium-sulfur batteries (mAh / g)
[0095]
[0096] Table 3 is the charge-discharge cycling data for lithium-sulfur batteries of Example 11 and Comparative Example 3. The test results show that the addition of 2.0% of the ionically conductive gel to the sulfur battery can increase the capacity of the sulfur electrode by about 150 mAh / g. The increase in the capacity of the sulfur electrode is due to the ionically conductive gel reducing the electrochemical polarization of the electrode and enhancing the electrochemical reaction kinetics.
Claims
1. A core-shell ion-conducting colloid, characterized in that, The core of the core-shell structure ion conductive colloid is styrene-butadiene rubber, and the shell is a polymer after polymerization of an organic sulfonate monomer, a nitrile-based monomer, and an acrylic ester monomer; the D50 particle size of the core-shell structure ion conductive colloid ranges from 0.1 to 2.0 μm.
2. The core-shell structured ionically conductive colloid of claim 1, wherein, The core-shell structure ion conductive colloid is soaked in electrolyte at 50℃ for 48 hours, the liquid absorption rate of the gel film is ≤100%, and the ion conductivity of the gel film after absorbing electrolyte is 10 -5 ~10 -3 Scm -1 .
3. The core-shell structured ionically conductive colloid according to claim 1 or 2, wherein The organic sulfonate monomer includes any one or a mixture of multiple of sodium vinyl sulfonate, sodium allyl sulfonate, sodium methacryl sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, and sodium styrene sulfonate, and preferably includes 2-acrylamido-2-methylpropanesulfonic acid monomer.
4. The core-shell structured ion conductive colloidal according to claim 1 or 2, wherein, The nitrile-based monomer includes at least one of acrylonitrile, methacrylonitrile, allyl cyanide, 2-methyl-3-butenenitrile, and N,N-diethyl cyanoacrylamide monomer, and preferably includes N,N-diethyl cyanoacrylamide monomer.
5. The core-shell structured ion conductive colloidal according to claim 1 or 2, wherein, The acrylic monomer includes at least one of the chemical formula CH2=CR1COOR2, wherein R1 is -H or -CH3, R2 is -(CH2) n CH3, n is an integer from 0 to 12; preferably the acrylic monomer includes at least one of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, vinyl acetate, and isooctyl acrylate.
6. The core-shell structured ion conductive colloidal according to claim 1 or 2, wherein, The mass ratio of the core-shell structure ion conductive colloid, the organic sulfonate monomer, the nitrile-based monomer, and the acrylic ester monomer is 100:3-15:5-30:0-20; preferably 100:5-8:20-25:8-15; and more preferably 100:5-8:20-25:8-12.
7. The method of producing a core-shell structured ion conductive colloidal according to any one of claims 1 to 6, wherein The method comprises: a. mixing styrene-butadiene rubber emulsion with deionized water, an organic sulfonate monomer, a nitrile-based monomer, and an acrylic ester monomer uniformly to obtain a mixed solution; preferably, the styrene-butadiene rubber emulsion is first mixed with deionized water uniformly to obtain solution A, and then the organic sulfonate monomer, the nitrile-based monomer, and the acrylic ester monomer are mixed with solution A uniformly to obtain the mixed solution; b. heating the mixed solution of step a to 50-75 °C, adding a water-soluble initiator to initiate polymerization for 6-48 hours; adjusting the pH of the product to 6.5-7.5 with lye after the reaction is completed to obtain a core-shell structure colloid emulsion; and the water-soluble initiator is preferably ammonium persulfate.
8. The method for preparing the core-shell structured ion-conducting colloid according to claim 7, characterized in that, The amount of the organic sulfonate monomer is 3wt%-15wt% of the solid mass of the core-shell structure colloid emulsion, and preferably 5wt%-15wt%; The amount of the nitrile-based monomer is preferably 5wt%-30wt% of the solid mass of the core-shell structure colloid emulsion; The amount of the acrylic ester monomer is preferably 0-20wt% of the solid mass of the core-shell structure colloid emulsion.
9. The method of producing a core-shell structured ion conductive colloid according to claim 7 or 8, wherein The nitrogen content in the solid mass of the core-shell structure colloid emulsion of step b is 1.0wt%-10.0wt%, and the solid content of the colloid emulsion is 20wt%-45wt%.
10. Application of the core-shell structure ion conductive colloid prepared by the method of any one of claims 1-6 or 7-9 in a battery, wherein the battery is a lithium ion battery or a sodium-lithium sub-battery, or a lithium-sulfur battery.