CN109473677B - Lithium ion battery, silicon cathode water system binder and preparation method thereof - Google Patents
Lithium ion battery, silicon cathode water system binder and preparation method thereof Download PDFInfo
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- CN109473677B CN109473677B CN201811236784.2A CN201811236784A CN109473677B CN 109473677 B CN109473677 B CN 109473677B CN 201811236784 A CN201811236784 A CN 201811236784A CN 109473677 B CN109473677 B CN 109473677B
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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
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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Abstract
The invention discloses a lithium ion battery, a silicon cathode aqueous binder and a preparation method thereof, wherein the preparation method comprises the following steps: reacting inorganic nanoparticles with a silane coupling agent to obtain modified inorganic nanoparticles; ammonium salinization is carried out on the modified inorganic nano particles, and the modified inorganic nano particle colloid is obtained by dehydration and ethanol drying of the solution. Adding a certain amount of chain extender into oligomer polyol and isocyanate under a certain condition, reacting to obtain a polyurethane prepolymer, and adding water into the polyurethane prepolymer for emulsification to obtain the waterborne polyurethane oligomer. And reacting and crosslinking the aqueous polyurethane oligomer and the modified inorganic nano particle jelly with a polyacrylic acid solution to obtain the lithium ion battery silicon negative electrode material. The invention has the beneficial effects that: the hardness and brittleness of the negative plate are solved by introducing the waterborne polyurethane oligomer on the modified inorganic nano particles, the processing flexibility of the negative plate is improved, and the overall adhesive force of the adhesive is enhanced; and an ammonium cation group is introduced, so that the circulating capacity of the battery cell is improved.
Description
Technical Field
The invention relates to the field of new energy, in particular to a lithium ion battery, a silicon cathode aqueous binder and a preparation method thereof.
Background
The theoretical gram capacity of the silicon negative electrode is about 10 times of that of graphite, the energy density of the battery can be obviously improved, but the volume of the silicon negative electrode expands by more than 300 percent after lithium is embedded, and the periodic cyclic stress can lead silicon particles to be pulverized, so that the cycle capacity of the battery core is poor. In the prior art, a silicon-carbon negative electrode is used as a negative electrode of a lithium battery, the silicon-carbon negative electrode is a graphite and silicon monoxide or silicon particle composite material, a binder used by the current silicon-carbon negative electrode is mainly modified PAA and PI, the vitrification degree of the PAA is high, the binding force is low, a formed film is hard and brittle and is easy to be irreversibly broken, the PI needs to be baked at a high temperature of more than 200 ℃, the production cost is high, and the large-scale production is not facilitated.
Disclosure of Invention
The invention mainly aims to provide a lithium ion battery, a silicon cathode aqueous binder and a preparation method thereof, and solves the problems of film-forming hard brittleness, too low binding power and poor cycle performance of a PAA binder.
The invention provides a preparation method of a silicon cathode water system binder, which comprises the following steps:
reacting inorganic nanoparticles with a silane coupling agent at a certain temperature T1 for a certain time T1 to obtain modified inorganic nanoparticles;
ammonium salinization is carried out on the modified inorganic nano particles to obtain a solution of the modified inorganic nano particles, the solution is dehydrated and dealcoholized, and modified inorganic nano particle jelly is obtained after drying under certain conditions;
reacting the modified inorganic nano particle jelly with a waterborne polyurethane oligomer at a certain temperature T5 for a period of time T4 to obtain a polymer A solution with a certain viscosity, and reacting the polymer A solution with a polyacrylic acid solution with a certain molecular weight at a certain temperature T6 for a period of time T5 to obtain the silicon cathode water-based binder.
Preferably, the inorganic nanoparticles are SiO2、TiO2ZnO, graphene, carbon nanotubes and quantum dots or a mixture thereof.
Preferably, the aqueous polyurethane oligomer is prepared by the steps of,
weighing a certain amount of oligomer polyol and isocyanate, stirring the oligomer polyol and the isocyanate for a certain time T2 at a certain temperature T2 in the presence of inert gas, cooling to a certain temperature T3, adding acetone, adding a certain amount of chain extender, and reacting at a certain temperature T4 for a certain time T3 to obtain a polyurethane prepolymer;
and adding deionized water into the polyurethane prepolymer under the condition of a certain stirring speed, and removing acetone in a vacuum environment at 50 ℃ to obtain the waterborne polyurethane oligomer.
Preferably, the oligomer polyol comprises one of polyester polyol, polyether polyol or a mixture thereof; the polyester polyol comprises one of or a mixture of polybutylene adipate diol, poly-caprolactone polyol, polyhexamethylene adipate diol and polyhexamethylene adipate neopentyl glycol ester diol, and the polyether polyol comprises one of or a mixture of polypropylene oxide diol, polypropylene oxide triol, polypropylene oxide tetraol, polypropylene oxide pentaol and polytetrahydrofuran diol.
Preferably, the temperature T1 is 70 to 80 ℃, the temperature T2 is 80 to 85 ℃, the temperature T3 is 40 to 45 ℃, the temperature T4 is 50 to 55 ℃, the temperature T5 is 70 to 95 ℃, the temperature T6 is 70 to 80 ℃, the time T1 is 72 to 80 hours, the time T2 is 2 to 2.5 hours, the time T3 is 2 to 2.5 hours, the time T4 is 2 to 3 hours, and the time T5 is 3 to 4 hours.
Preferably, the silicon anode water system binder is prepared by a mixture of the following components in percentage by mass, the sum of the following components in percentage by mass is 100%,
1 to 2 percent of modified inorganic nano particle jelly,
20 to 25 percent of polyacrylic acid solution,
75-80% of waterborne polyurethane oligomer.
The invention also provides a silicon cathode water-based binder, and the silicon cathode water-based binder prepared by the preparation method of the silicon cathode water-based binder.
Preferably, the viscosity of the silicon negative electrode aqueous binder ranges from 8000mPa · s to 20000mPa · s and the solid content ranges from 5% to 15%.
The invention also provides a lithium battery, and the negative plate of the lithium battery comprises the silicon negative electrode aqueous binder prepared by the preparation method of the silicon negative electrode aqueous binder.
Preferably, the negative electrode sheet is made of a mixture of the following components in percentage by mass, the sum of the following components in mass content is 100%,
92 to 97 percent of silicon carbon,
2 to 4 percent of silicon cathode aqueous binder,
2 to 4 percent of conductive agent.
The invention has the beneficial effects that: the introduced waterborne polyurethane oligomer chain segment is non-combustible and has good elasticity, the hard brittleness of a rigid binder PAA is solved, the processing flexibility of the negative plate is increased, the processing window is widened, and the processing performance is improved; the waterborne polyurethane oligomer has good cohesive force, and simultaneously, the carboxylate radical of the chain extender for synthesizing the waterborne polyurethane oligomer and the silicon surface radical have chemical action, so that the integral cohesive force of the binder is enhanced; the integral processing temperature is not high, the production cost is low, and the large-scale production is facilitated; ammonium cation groups are introduced, so that the adhesive has excellent lithium ion conductivity, and the cycle capacity of a battery cell is improved.
Drawings
Fig. 1 is a schematic flow chart of a method for preparing an aqueous binder for a silicon negative electrode according to an embodiment of the present invention;
FIG. 2 is a graph of viscosity of negative electrode slurry versus standing time for the aqueous binder for silicon negative electrodes of examples 1 to 3 of the present invention and comparative examples 1 to 3;
FIG. 3 is a drawing graph of a lithium battery negative electrode material corresponding to the aqueous binder for silicon negative electrodes of examples 1 to 3 of the present invention;
FIG. 4 is a graph showing the ratio discharge capacity retention ratios of examples 1 to 3 of the present invention and comparative examples 1 to 3;
FIG. 5 is a graph showing the rate charge capacity retention ratios of examples 1 to 3 of the present invention and comparative examples 1 to 3;
FIG. 6 is a graph showing the ratio high and low temperature capacity retention ratios of examples 1 to 3 of the present invention and comparative examples 1 to 3;
the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the description in the present invention as referring to "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
Referring to fig. 1, a method for preparing a silicon negative electrode aqueous binder according to an embodiment of the present invention includes the following steps:
s11, reacting the inorganic nanoparticles with a silane coupling agent at a certain temperature T1 for a certain time T1 to obtain modified inorganic nanoparticles;
and S12, ammonium salinizing the modified inorganic nano particle to obtain a solution, dehydrating the solution, adding ethanol, and drying to obtain a modified inorganic nano particle colloid.
And S21, adding a certain amount of chain extender into oligomer polyol and isocyanate under a certain condition, and reacting to obtain the polyurethane prepolymer.
And S22, adding deionized water into the polyurethane prepolymer under the condition of strong stirring, and removing acetone in a vacuum environment at 50 ℃ to obtain the waterborne polyurethane oligomer.
And S3, mixing the aqueous polyurethane oligomer, the modified inorganic nanoparticle jelly and a polyacrylic acid solution according to a certain proportion, and reacting to obtain the silicon cathode aqueous binder.
The embodiment of the invention improves the adhesive in the negative electrode material of the lithium ion battery, endows the PAA (polyacrylic acid solution) binder with the performances of flexibility and elasticity by introducing the aqueous polyurethane oligomer chain segment into the binder, solves the problem of hard brittleness of the PAA binder, improves the overall binder of the binder, and ensures that the inorganic nano particles are ammonium-salted and ammonium cationic groups are introduced, so that the binder has excellent lithium ion conductivity.
Further, the inorganic nanoparticles are SiO2、TiO2ZnO, graphene, carbon nanotubes and quantum dots or mixtures thereof.
Further, the oligomeric polyol includes polyester polyol, polyether polyol, or mixtures thereof.
Further, the polyester polyol includes polybutylene adipate diol, poly-caprolactone diol, polyhexamethylene adipate neopentyl glycol diol, or a mixture thereof, and the polyether polyol includes polyoxypropylene diol, polyoxypropylene triol, polyoxypropylene tetraol, polyoxypropylene pentaol, and polytetrahydrofuran diol, or a mixture thereof.
Further, the isocyanate includes diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, 1, 5-naphthalene diisocyanate, or a mixture thereof.
Further, chain extenders include tertiary nitrogen atom containing diols, and other polyols and polyamines. Including dimethylolpropionic acid, N-methyldiethanolamine, N-ethyldiethanolamine, diethylenetriamine, triethylenetetramine, propylene glycol, butylene glycol, diethylene glycol and mixtures thereof.
Further, the silicon cathode water-based binder is prepared from a mixture of the following components in percentage by mass, wherein the total mass content of the following components is 100%, the modified inorganic nanoparticle colloid is 1% -2%, the polyacrylic acid solution is 20% -25%, and the aqueous polyurethane oligomer is 75% -80%. .
In this embodiment, the silane coupling agent is propyl trimethoxy silicon, and the inorganic nanoparticles are SiO2The oligomer polyol is poly (butylene adipate) glycol, the isocyanate is 4, 4-diphenylmethane diisocyanate, and the chain extender is 2, 2-dimethylolpropionic acid.
Concretely, silane coupling agent propyl trimethoxy silicon and SiO are weighed2Dissolving the aqueous solution (15 percent by weight) with ethanol, and reacting for 24 hours at the temperature of 70-80 ℃ under the protection of inert gas to obtain the activated nano silicon dioxide particles.
Specifically, according to the molar ratio of the silane coupling agent to the tri-n-butylamine and the concentrated hydrochloric acid of 1: 1:1, weighing tri-n-butylamine and concentrated hydrochloric acid, adding into the solvent after the reaction, and continuing the reaction for 20 to 26 hours at a temperature of between 65 and 75 ℃. Dehydrating the solution, drying with ethanol to obtain modified inorganic nano particle jelly, and storing for later use.
Specifically, polyester polyol and isocyanate are weighed according to the molar ratio of 1: 1.05-1: 1.08, in the embodiment, polybutylene adipate glycol (molecular chain 1000) and 4, 4-diphenylmethane diisocyanate are weighed and added into a three-neck flask, the mixture is stirred under the protection of nitrogen at the temperature of 80-85 ℃, and the condensation reflux reaction is carried out for 2-2.5 hours; then cooling to 40-45 ℃, adding solvent acetone, adding 2, 2-dimethylolpropionic acid chain extender, heating to 50-55 ℃, and continuing to react for 2-2.5 h to obtain the polyurethane prepolymer with the molecular weight of 1-2 ten thousand. After the reaction was complete, a quantitative amount of deionized water was added with vigorous stirring. And finally removing acetone at the temperature of 50 ℃ in a vacuum environment to obtain the transparent waterborne polyurethane oligomer with the solid content of 15-25 wt%.
Specifically, weighing and reacting the waterborne polyurethane oligomer with the modified inorganic nanoparticle jelly for 2 hours at 70-80 ℃ to obtain a polymer A solution with the viscosity of 5000-8500 mPa & s.
Specifically, the polymer A solution, the conductive agent and the polyacrylic acid solution (molecular weight of 300000-600000) are mixed for 3h to 4h at 70 ℃ to 80 ℃ according to the mass ratio of 95:3:1 or 94:3:3 or 93:3:4 to obtain the silicon negative electrode aqueous binder with the viscosity of 8000mPa & s to 20000mPa & s and the solid content of 5% to 15%.
Specifically, the silicon cathode aqueous binder is placed in a vacuum oven and baked for 2 to 3 hours at the temperature of between 110 and 125 ℃ to obtain the silicon cathode material (SiO) of the lithium ion battery2@PAA-PU)。
Specifically, the silicon negative electrode material of the lithium ion battery is made into a lithium battery negative electrode sheet, and then the corresponding lithium battery is obtained.
The invention also provides a silicon cathode water-based binder which is prepared by the preparation method of the silicon cathode water-based binder, the viscosity range of the silicon cathode water-based binder is 8000mPa & s-20000mPa & s, and the solid content range is 5% -15%.
The invention also provides a lithium battery, wherein the negative plate comprises the silicon negative electrode aqueous binder prepared by the preparation method of the silicon negative electrode aqueous binder, the negative plate is prepared from the following mixture of components in percentage by mass, the total mass content of the following components is 100%,
92 to 97 percent of silicon carbon,
2 to 4 percent of silicon cathode aqueous binder,
2 to 4 percent of conductive agent.
The invention proposes the following specific embodiments:
example 1
Mixing the polymer A solution, the conductive agent and a polyacrylic acid solution (PAA) (molecular weight of 300000-600000) at a mass ratio of 95:3:1 at 70-80 ℃ for 3-4 h to obtain the silicon negative electrode water-based binder with the viscosity of 8000-20000 mPa-s and the solid content of 5-15%.
And placing the silicon cathode aqueous binder in a vacuum oven, and baking for 2-3h at 110-125 ℃ to obtain the lithium ion battery silicon cathode material.
And manufacturing the silicon negative electrode material of the lithium ion battery into a lithium battery negative electrode sheet so as to obtain the corresponding lithium battery.
Example 2
Mixing the polymer A solution, the conductive agent and a polyacrylic acid solution (PAA) (molecular weight of 300000-600000) at a mass ratio of 94:3:3 at 70-80 ℃ for 3-4 h to obtain the silicon negative electrode water-based binder with the viscosity of 8000-20000 mPa-s and the solid content of 5-15%.
And placing the silicon cathode aqueous binder in a vacuum oven, and baking for 2-3h at 110-125 ℃ to obtain the lithium ion battery silicon cathode material.
And manufacturing the silicon negative electrode material of the lithium ion battery into a lithium battery negative electrode sheet so as to obtain the corresponding lithium battery.
Example 3
Mixing the polymer A solution, the conductive agent and a polyacrylic acid solution (PAA) (molecular weight of 300000-600000) at a mass ratio of 93:3:4 at 70-80 ℃ for 3-4 h to obtain the silicon negative electrode aqueous binder with the viscosity of 8000-20000 mPa-s and the solid content of 5-15%.
And placing the silicon cathode aqueous binder in a vacuum oven, and baking for 2-3h at 110-125 ℃ to obtain the lithium ion battery silicon cathode material.
And manufacturing the silicon negative electrode material of the lithium ion battery into a lithium battery negative electrode sheet so as to obtain the corresponding lithium battery.
Comparative example 1
Comparative example 1 is the same as example 1 except that polyacrylic acid (PAA) commercially available from a company is used in combination as the binder. Silicon carbon: conductive agent SP: PAA is 92:3: 5.
Comparative example 2
Comparative example 2 is the same as example 1 except that styrene-butadiene rubber (SBR) commercially available from a company is used in combination with polyacrylic acid (PAA) as a binder. Silicon carbon: the conductive agent SP, SBR and PAA are respectively 92:3:1: 4.
Comparative example 3
Comparative example 3 is the same as example 1 except that polyacrylic acid (PAA) commercially available from a company is used in combination with sodium carboxymethylcellulose (CMC) as a binder. The difference is that silicon carbon: conductive agent SP: CMC: PAA is 92:3:1: 4.
the lithium batteries prepared from the above examples 1-3 and comparative examples 1-3 were tested, and specifically, the lithium batteries were placed in a vacuum oven and baked at 125 ℃ for 2-3h at 110-.
Assembling the full cell: and winding the positive and negative pole pieces and the ceramic diaphragm to obtain the bare cell. And then carrying out hot-pressing shaping, top side sealing, baking, electrolyte injection, vacuum packaging, formation, secondary sealing and capacity grading to obtain the 3.5Ah soft package battery.
FIG. 2 is a graph showing the relationship between the viscosity of the negative electrode slurry of examples 1 to 3 and comparative examples 1 to 3 and the standing time, measured by using a 250mL glass to hold the slurry and measuring the change in viscosity of the slurry after the slurry is taken out of the pot for 24 hours by using a rotational viscometer. In the figure, curves 1 to 6 are examples 1 to 3 and comparative examples 1 to 3, respectively, namely curve 1 corresponds to example 1, curve 2 corresponds to example 2, curve 3 corresponds to example 3, curve 4 corresponds to comparative example 1, curve 5 corresponds to comparative example 2, and curve 6 corresponds to comparative example 3, and it can be seen from the figure that the viscosity change range of examples 1 to 3 is lower than that of comparative examples 1 to 3 with the increase of the standing time, which shows that the stability of the components in the examples is higher than that of the comparative examples.
FIG. 3 shows the silicon cathode material (SiO) of lithium ion battery2@ PAA-PU) by coating SiO2@ PAA-PU solution on a polytetrafluoroethylene plate, drying to form a film, and then drying in vacuum at 120 ℃ for 2h to ensure full crosslinking. Then, a 5cm × 1cm piece was cut out and subjected to a tensile test on a tensile machine. The drawing rate was 50 mm/min. In the figure, curves 1-6 are examples 1-3 and comparative examples 1-3 respectively, namely curve 1 corresponds to example 1, curve 2 corresponds to example 2, curve 3 corresponds to example 3, curve 4 corresponds to comparative example 1, curve 5 corresponds to comparative example 2, and curve 6 corresponds to comparative example 3, and it can be seen from the figure that when the elongation rate is close to 50%, the tensile strength reaches the maximum value, and the tensile strength is reduced slowly when the elongation rate is 50% -200%, and still has a certain tensile strength, which indicates that the tensile strength is good, the material is not easy to break, and indicates that the material has excellent tensile strength and is suitable for large volume expansion of a silicon cathode system of a lithium ion battery.
The performance of the electrode materials of examples 1-3 and comparative examples 1-3 were now compared by testing the stability index of the negative electrode slurry with a Turbscan backscattering meter over a period of four hours.
As can be seen from the above table, the slurries of examples 1-3 all had higher stability than comparative examples 1-3, higher peel strength than comparative examples 1-3, no cracking of the coatings of examples 1-3, cracking of the coatings of comparative examples 1 and 3, and lower rebound rates for fully charged sheets than comparative examples 1-3.
FIGS. 4 and 5 are graphs of the rate discharge capacity retention rate distribution of examples 1-3 and comparative examples 1-3 and the rate charge capacity retention rate distribution of examples 1-3 and comparative examples 1-3, respectively, and the rate charge capacity of the full cell at 0.33C, 0.5C, 1, 2C was tested; and rate discharge capacity of full cell at 0.33C, 0.5C, 1C, 2C, 3C, 4C. It can be seen that, as shown in the graphs, curves 1 to 6 correspond to examples 1 to 3 and comparative examples 1 to 3, respectively, i.e., curve 1 corresponds to example 1, curve 2 corresponds to example 2, curve 3 corresponds to example 3, curve 4 corresponds to comparative example 1, curve 5 corresponds to comparative example 2, and curve 6 corresponds to comparative example 3, the capacity retention rates of examples 1 to 3 in the case of rate discharge and rate charge are higher than those of comparative examples 1 to 3, the lithium ion conductivity of ammonium cations, and PU itself has a certain liquid absorption rate, so that the capacity retention rates of example 1 to 3 in the case of rate discharge and rate charge are higher than those of comparative examples 1 to 3.
The performance of the batteries prepared from the electrode materials of examples 1 to 3 and comparative examples 1 to 3 was now compared
From the table above, the capacity exertion and the capacity-dividing first-effect of the positive electrodes of the examples 1-3 are higher than those of the comparative examples 1-3, and under the cycles of 500 circles and 1000 circles at 25 ℃ and 45 ℃, the capacity retention rates of the examples 1-3 are higher than those of the comparative examples 1-3 and are all more than 80%, which shows that the silicon negative electrode material of the lithium ion battery prepared by the scheme has good beneficial effects on the application of the battery.
FIG. 6 is a graph showing the high and low temperature capacity retention ratios of examples 1 to 3 and comparative examples 1 to 3, in which the charge and discharge properties of the full cell at-25 deg.C, 0 deg.C, 25 deg.C, and 45 deg.C were measured under the conditions of 0.5C charge and 0.5C discharge. In the figure, curves 1 to 6 are respectively shown as examples 1 to 3 and comparative examples 1 to 3, namely the curve 1 corresponds to the example 1, the curve 2 corresponds to the example 2, the curve 3 corresponds to the example 3, the curve 4 corresponds to the comparative example 1, the curve 5 corresponds to the comparative example 2, the curve 6 corresponds to the comparative example 3, the lithium ion battery silicon negative electrode material prepared by the water-based binder SiO2@ PAA-PU in the examples 1 to 3 has obviously improved high and low temperature charging performance, the capacity retention rate can reach 88% at-20 ℃, and the synthesized binder has good low temperature dynamic performance, which indicates that the ammonium cations contained in the binder can increase the low temperature conductivity to a certain extent.
The invention has the beneficial effects that: the introduced waterborne polyurethane oligomer chain segment is non-combustible and has good elasticity, the hard brittleness of a rigid binder PAA is solved, the processing flexibility of the negative plate is increased, the processing window is widened, and the processing performance is improved; the waterborne polyurethane oligomer has good cohesive force, and simultaneously, the carboxylate radical of the chain extender for synthesizing the waterborne polyurethane oligomer and the silicon surface radical have chemical action, so that the integral cohesive force of the binder is enhanced; the integral processing temperature is not high, the production cost is low, and the large-scale production is facilitated; ammonium cation groups are introduced, so that the adhesive has excellent lithium ion conductivity, and the cycle capacity of a battery cell is improved.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A preparation method of a silicon negative electrode water system binder is characterized by comprising the following steps:
reacting inorganic nanoparticles with a silane coupling agent at a certain temperature T1 for a certain time T1 to obtain modified inorganic nanoparticles;
ammonium salinization is carried out on the modified inorganic nano particles to obtain a solution of the modified inorganic nano particles, the solution is dehydrated and dealcoholized, and modified inorganic nano particle jelly is obtained after drying under certain conditions;
reacting the modified inorganic nano particle jelly with a waterborne polyurethane oligomer at a certain temperature T5 for a period of time T4 to obtain a polymer A solution with a certain viscosity, and reacting the polymer A solution with a polyacrylic acid solution with a certain molecular weight at a certain temperature T6 for a period of time T5 to obtain a silicon cathode water-based binder;
the molecular weight of the polyacrylic acid includes 300000-600000.
2. The method of preparing the aqueous binder for silicon negative electrode of claim 1, wherein the inorganic nanoparticles are SiO2、TiO2、ZnO、One or a mixture of graphene, carbon nanotubes and quantum dots.
3. The method for preparing the aqueous binder for silicon negative electrode of claim 1, wherein the aqueous polyurethane oligomer is prepared by the steps of,
weighing a certain amount of oligomer polyol and isocyanate, stirring the oligomer polyol and the isocyanate for a certain time T2 at a certain temperature T2 in the presence of inert gas, cooling to a certain temperature T3, adding acetone, adding a certain amount of chain extender, and reacting at a certain temperature T4 for a certain time T3 to obtain a polyurethane prepolymer;
and adding deionized water into the polyurethane prepolymer under the condition of a certain stirring speed, and removing acetone in a vacuum environment at 50 ℃ to obtain the waterborne polyurethane oligomer.
4. The method for preparing the silicon negative electrode aqueous binder according to claim 3, wherein the oligomer polyol comprises one of polyester polyol, polyether polyol or a mixture thereof; the polyester polyol comprises one of or a mixture of polybutylene adipate diol, poly-caprolactone polyol, polyhexamethylene adipate diol and polyhexamethylene adipate neopentyl glycol ester diol, and the polyether polyol comprises one of or a mixture of polypropylene oxide diol, polypropylene oxide triol, polypropylene oxide tetraol, polypropylene oxide pentaol and polytetrahydrofuran diol.
5. The method for preparing the aqueous binder for silicon negative electrode of claim 3, wherein the temperature T1 is 70 to 80 ℃, the temperature T2 is 80 to 85 ℃, the temperature T3 is 40 to 45 ℃, the temperature T4 is 50 to 55 ℃, the temperature T5 is 70 to 95 ℃, the temperature T6 is 70 to 80 ℃, the time T1 is 72 to 80 hours, the time T2 is 2 to 2.5 hours, the time T3 is 2 to 2.5 hours, the time T4 is 2 to 3 hours, and the time T5 is 3 to 4 hours.
6. The method for producing the silicon anode water-based binder according to claim 3, wherein the silicon anode water-based binder is produced from a mixture of the following components in mass percentage, the sum of the following components being 100%,
1 to 2 percent of modified inorganic nano particle jelly,
20 to 25 percent of polyacrylic acid solution,
75-80% of waterborne polyurethane oligomer.
7. A silicon negative electrode water-based binder, characterized by being produced by the method for producing a silicon negative electrode water-based binder according to any one of claims 1 to 6.
8. The aqueous binder for a silicon negative electrode as claimed in claim 7, wherein the aqueous binder for a silicon negative electrode has a viscosity ranging from 8000 to 20000 mPa-s and a solid content ranging from 5 to 15%.
9. A lithium ion battery, characterized in that the negative plate comprises the aqueous binder of silicon negative electrode prepared by the method for preparing the aqueous binder of silicon negative electrode according to any one of claims 1 to 6.
10. The lithium ion battery of claim 9, wherein the negative electrode sheet is made of a mixture of the following components in mass percentage, the sum of the mass contents of the following components being 100%,
92 to 97 percent of silicon carbon,
2 to 4 percent of silicon cathode aqueous binder,
2 to 4 percent of conductive agent.
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| CN110364734A (en) * | 2019-06-06 | 2019-10-22 | 华南理工大学 | High-performance water-based compounding negative electrode of lithium ion battery binder and preparation method and application |
| CN110676456B (en) * | 2019-09-20 | 2021-10-26 | 南方科技大学 | Three-dimensional network structure binder and preparation method and application thereof |
| CN111180733B (en) * | 2020-01-03 | 2021-10-08 | 南方科技大学 | Three-dimensional network water-based composite binder and application thereof in lithium ion battery |
| CN111653787B (en) * | 2020-06-30 | 2021-09-28 | 陕西煤业化工技术研究院有限责任公司 | Silicon-based negative electrode three-dimensional network polyacrylic acid binder and preparation method thereof |
| CN113299916B (en) * | 2021-05-17 | 2023-11-28 | 珠海冠宇动力电池有限公司 | Adhesive, negative plate containing adhesive and lithium ion battery |
| CN117363304A (en) * | 2023-10-31 | 2024-01-09 | 南开大学 | Polyurethane binder for lithium ion battery pole piece, and preparation method and application thereof |
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| CN102760883A (en) * | 2012-07-13 | 2012-10-31 | 中国科学院广州能源研究所 | Novel chitosan used for lithium ion cell and derivative water-based binder of chitosan |
| CN103074007A (en) * | 2012-12-27 | 2013-05-01 | 上海交通大学 | Water-based adhesive used in silicon anode of lithium ion battery and preparation method of silicon anode |
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| CN105449220A (en) * | 2015-12-31 | 2016-03-30 | 天津市捷威动力工业有限公司 | Aqueous binder used for lithium ion battery and lithium ion battery thereby |
| CN105732940A (en) * | 2016-05-11 | 2016-07-06 | 江南大学 | Preparation method of waterborne polyurethane-silicon dioxide nano composite emulsion |
| CN108342181A (en) * | 2018-02-28 | 2018-07-31 | 佛山市三水日邦化工有限公司 | A kind of single-component water-based polyurethane adhesive of water resistant, high temperature resistant and preparation method thereof |
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| CN102760883A (en) * | 2012-07-13 | 2012-10-31 | 中国科学院广州能源研究所 | Novel chitosan used for lithium ion cell and derivative water-based binder of chitosan |
| CN103074007A (en) * | 2012-12-27 | 2013-05-01 | 上海交通大学 | Water-based adhesive used in silicon anode of lithium ion battery and preparation method of silicon anode |
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