CN112838271B - Preparation method and preparation system of electrolyte - Google Patents
Preparation method and preparation system of electrolyte Download PDFInfo
- Publication number
- CN112838271B CN112838271B CN202110408556.4A CN202110408556A CN112838271B CN 112838271 B CN112838271 B CN 112838271B CN 202110408556 A CN202110408556 A CN 202110408556A CN 112838271 B CN112838271 B CN 112838271B
- Authority
- CN
- China
- Prior art keywords
- solvent
- molecular sieve
- tank
- storage tank
- electrolyte
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D15/08—Selective adsorption, e.g. chromatography
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/70—Pre-treatment of the materials to be mixed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
- B01J20/16—Alumino-silicates
- B01J20/18—Synthetic zeolitic molecular sieves
- B01J20/186—Chemical treatments in view of modifying the properties of the sieve, e.g. increasing the stability or the activity, also decreasing the activity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The invention relates to a preparation method of electrolyte and an electrolyte preparation system. And treating an organic solvent in the electrolyte through a first molecular sieve column, mixing the organic solvent with the added components in the electrolyte in a stirring tank, passing through a second molecular sieve column, and then mixing the organic solvent with other components in the stirring tank to prepare the electrolyte. The invention provides a novel process flow system and a novel electrolyte preparation method, wherein the preparation method is matched with the process flow system. And the first molecular sieve column can be used for removing water and the like from the solvent, and the second molecular sieve column can be used for removing impurities, catalyzing and the like from the auxiliary agent and the like in the electrolyte, so that the prepared electrolyte has good coulombic efficiency and capacity retention rate. In addition, a novel auxiliary agent is developed and matched with the process flow system for application, and the effect is better.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a preparation method of electrolyte and an electrolyte preparation system.
Background
The secondary battery is a battery which is widely applied at present and can be repeatedly charged and discharged, and the application of the secondary battery relates to a plurality of fields. The secondary battery includes various types such as button battery, cylindrical battery, pouch battery, and prismatic battery, and is currently most widely used as a lithium ion battery. It is found that the addition of a small amount of additive to the electrolyte of a lithium ion battery can significantly improve the electrochemical performance of the electrolyte, and the electrolytic process is in a better state. Therefore, in the current electrolytic solution, additives have been indispensable additive components.
In regard to the preparation of the electrolyte, a conventional method is generally used, in which an organic solvent in the electrolyte is mixed with a desired lithium salt and additives and stirred. However, this method does not treat the raw material components, and therefore, the requirements for the raw material are relatively strict, for example, the water content of a solvent or the like needs to be high, and the like. This also results in high raw material costs and also requires strict and, with minor precautions, control of the charging and reaction processes, which may have an effect on the performance of the battery.
The invention designs a novel preparation process flow which can treat the solvent with high water content easily and can also treat additives and the like to a certain extent. It reduces the requirements for raw materials and also improves the comprehensive performance of the battery. In addition, the invention also develops an addition agent which can be matched with the novel process flow or the novel electrolyte preparation method, and the addition agent can further improve the effect of the battery.
Disclosure of Invention
The invention provides a preparation method of electrolyte and an electrolyte preparation system aiming at the defects of the prior art, which overcome some defects in the prior art.
The purpose of the invention is realized by the following technical scheme:
one invention point of the invention is to provide a preparation method of electrolyte, the electrolyte comprises an organic solvent, salt and an additive component, and the additive component comprises an additive and/or an auxiliary agent; the method comprises the following steps:
(1) the organic solvent enters a solvent tank; (2) the organic solvent enters a solvent storage tank from a solvent tank; (3) conveying the organic solvent in the solvent storage tank to a first molecular sieve column, returning the organic solvent to the solvent storage tank after flowing out of the first molecular sieve column, and testing the water content of the organic solvent; (4) conveying the organic solvent in the solvent storage tank to a stirring tank; (5) feeding the auxiliary agent into a stirring tank in a glove box, and mixing and stirring the auxiliary agent and the organic solvent to obtain a solution; after stirring, transferring the solution into a solvent treatment tank; (6) after the solution enters the solvent treatment tank, conveying the solution in the solvent treatment tank to a second molecular sieve column, and returning the solution to the solvent treatment tank after the solution flows out of the second molecular sieve column; controlling the flow rate of the second molecular sieve column to be 0.4V-3V L/min, wherein V is the volume of the molecular sieve in the second molecular sieve column; (7) conveying the solution in the solvent treatment tank to a storage tank; (8) the solution is conveyed into the stirring tank from the storage tank; (9) and after the solution is injected into a stirring tank, sequentially adding the raw materials except the auxiliary agent and the organic solvent in the electrolyte into the stirring tank in a glove box, and mixing and stirring the raw materials and the solution to obtain the electrolyte.
Further, the molecular sieve in the second molecular sieve column is a modified molecular sieve, and the flow rate of the molecular sieve flowing through the second molecular sieve is controlled to be 1.5V L/min.
Further, in step (3), if the water content in the organic solvent is greater than 15 ppm, the organic solvent can be circulated in the first molecular sieve column for a plurality of times to remove water, and when the water content of the organic solvent is reduced to <15 ppm.
Further, the organic solvent or the solution in the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column is conveyed to the next step by the pressure of the protective gas; in the electrolyte preparation process, the vacuum degree of the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank is 0-50 KPa, such as 0 KPa, 10 KPa, 20 KPa, 30 KPa, 40 KPa and 50 KPa.
Further, the raw materials of the auxiliary agent comprise a yellow blood salt and a ferric iron salt, and the yellow blood salt and the ferric iron salt can partially synthesize the Prussian blue.
Further, the additive includes a carbonate-based additive.
Further, the salt includes lithium salt, potassium salt, sodium salt.
Further, the organic solvent comprises at least one of dimethyl carbonate, methyl ethyl carbonate, ethyl acetate, methyl propionate and ethyl propionate solvents.
Further, the preparation method of the modified molecular sieve comprises the following steps: dissolving the modified compound in a solvent under a protective atmosphere, heating to the boiling point of the solvent after complete dissolution, adding molecular sieve powder into the solvent, adding alkali, stirring, reacting at the temperature for 0.5-2 hours, and performing suction filtration after the reaction is finished, wherein the pH value is 8-9; washing with weak acid for 1-3 times after suction filtration, and drying at 200 ℃ for 10-20 hours; washing with water for 1-2 times, drying at 500 deg.C for 3-6 hr, washing with alcohol, hot pressing at 200 deg.C, and drying to obtain the modified molecular sieve.
Further, the solvent is at least one of methyl acetate, ethyl acetate, propyl acetate and toluene.
Further, after rinsing with water, the drying temperature is increased at 5 ℃ to 8 ℃/min.
Further, the modified molecular sieve is a modified 4A molecular sieve, a modified 3A molecular sieve, a modified 5A molecular sieve, a modified 10Z molecular sieve, a modified 13Z molecular sieve, a modified Y-type molecular sieve, a modified MCM molecular sieve or a modified ZSM molecular sieve.
Further, the modifying compound is an alkyl compound or a silane compound.
It is another aspect of the invention to provide an electrolyte preparation system for use in a method according to any one of the preceding paragraphs, the system comprising: at least one solvent tank for holding solvent, at least one solvent storage tank, at least one solvent treatment tank, at least one holding tank, at least one agitation tank, at least one first molecular sieve column, at least one second molecular sieve column.
One end of the solvent tank is connected with a solvent source so that a solvent enters the solvent tank after being fed, and the other end of the solvent tank is communicated with the solvent storage tank so that the solvent enters the solvent storage tank; the outlet end of the solvent storage tank is respectively connected with the inlet end of the first molecular sieve column and the inlet end of the stirring tank so that the solvent in the solvent storage tank can selectively enter the first molecular sieve column or the stirring tank;
the outlet end of the first molecular sieve column is connected with the inlet end of the solvent storage tank so that the solvent passing through the first molecular sieve column enters the solvent storage tank;
the outlet end of the solvent treatment tank is respectively connected with the inlet end of the second molecular sieve column and the inlet end of the storage tank so that the solvent in the solvent treatment tank can selectively enter the second molecular sieve column or the storage tank;
the outlet end of the second molecular sieve column is connected with the inlet end of the solvent treatment tank so that the solvent passing through the second molecular sieve column enters the solvent treatment tank; the modified molecular sieve of any one of claims 1 to 3 is disposed in the second molecular sieve column;
the outlet end of the storage tank is connected with the inlet end of the stirring tank so that the liquid in the storage tank flows into the stirring tank;
the stirring tank is provided with a feed inlet and an outlet end connected with the inlet end of the storage tank.
Further, the feed port of the stirring tank is connected with a glove box so that the feeding is carried out in the glove box, and lithium salt, additive components, auxiliaries and the like can be added from the glove box.
Further, a 4A molecular sieve is arranged in the first molecular sieve column; the molecular sieve in the second molecular sieve column is the modified molecular sieve in any section above.
Further, the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column are all independently connected with a protective gas source; the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are all independently connected with a vacuum pumping pump.
Further, the solvent tank, the first molecular sieve column, the second molecular sieve column and the stirring tank are respectively connected with a protective gas source through a pipeline A, a pipeline E, a pipeline K and a pipeline I;
the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are respectively connected with a vacuum pumping pump through a pipeline C, a pipeline O, a pipeline P and a pipeline H;
the solvent tank is connected with the solvent storage tank through a pipeline B; the outlet end of the solvent storage tank is connected with the inlet end of the first molecular sieve column through a pipeline D; the outlet end of the first molecular sieve column is connected with the inlet end of the solvent storage tank through a pipeline F; the outlet end of the solvent storage tank is connected with the inlet end of the stirring tank through a pipeline G;
the outlet end of the solvent treatment tank is connected with the inlet end of the second molecular sieve column through a pipeline J; the outlet end of the second molecular sieve column is connected with the inlet end of the solvent treatment tank through a pipeline L; the outlet end of the solvent treatment tank is connected with the inlet end of the storage tank through a pipeline M;
the outlet end of the storage tank is connected with the inlet end of the stirring tank through a pipeline N; the outlet end of the stirring tank is connected with the inlet end of the solvent treatment tank through a pipeline Q.
The invention has the following main beneficial effects:
the invention provides a novel process flow system and a novel electrolyte preparation method, wherein the preparation method is matched with the process flow system. In the process flow system or the preparation method, the first molecular sieve column and the second molecular sieve column are added, the first molecular sieve column can be used for removing water and the like from a solvent, and the second molecular sieve column can be used for removing impurities, catalyzing and the like from an auxiliary agent and the like in the electrolyte, so that the prepared electrolyte has good coulombic efficiency and capacity retention rate.
And the application of the modified molecular sieve can supplement the electrolyte components and the process method in the application, so that a better comprehensive effect is realized.
In addition, a novel auxiliary agent is developed and can be matched with the process flow system or the preparation method in the application. The raw materials of the auxiliary agent are the yellow blood salt and the ferric iron salt, and the auxiliary agent is matched with the process flow system for application, so that the effect is better. The application of the molecular sieve column in the process flow system is beneficial to generating a very small amount of Prussian blue by the aid of the auxiliary raw material and removing the water and some impurities of the solvent. The auxiliary agent can be used as an additive and can also be mixed with a conventional additive for application. In the charging and discharging process, a small amount of Prussian blue is generated, so that a more stable and compact interface film can be generated on the surface of the electrode to a certain extent, the electrode is protected, and the further decomposition of the electrolyte or the organic solvent can be prevented to a certain extent.
Drawings
FIG. 1 is a process flow diagram for the preparation of the electrolyte of the present application.
FIG. 2 is a Transmission Electron Micrograph (TEM) of the surface of an electrode shown in test example 1 of example 8 of the present application.
Fig. 3 and 4 are Transmission Electron Micrographs (TEMs) of the electrode surface shown in experimental example 2 of example 4 of the present application.
Fig. 5 is a Scanning Electron Microscope (SEM) image of the surface of the negative electrode shown in experimental example 1 in example 8 of the present application.
Fig. 6 is a Scanning Electron Microscope (SEM) sectional view of the surface of the negative electrode shown in experimental example 1 in example 8 of the present application.
Fig. 7 is a Scanning Electron Microscope (SEM) image of the surface of the negative electrode shown in experimental example 2 in example 8 of the present application.
Fig. 8 is a Scanning Electron Microscope (SEM) sectional view of the surface of the negative electrode shown in experimental example 2 in example 8 of the present application.
Fig. 9 is a Scanning Electron Microscope (SEM) image of the surface of the negative electrode shown in experimental example 3 in example 8 of the present application.
FIG. 10 is a Scanning Electron Microscope (SEM) sectional view of the surface of a negative electrode shown in Experimental example 3 of example 8 of the present application.
Fig. 11 is a Scanning Electron Microscope (SEM) image of the surface of the negative electrode shown in experimental example 5 in example 8 of the present application.
Fig. 12 is a Scanning Electron Microscope (SEM) image of the surface of the negative electrode shown in experimental example 6 of example 8 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. 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.
Example 1
An electrolyte preparation process flow system, as shown in fig. 1, comprises at least one solvent tank 10 for storing solvent, at least one solvent storage tank 4, at least one solvent treatment tank 3, at least one storage tank 2, at least one stirring tank 1, at least one first molecular sieve column 5 and at least one second molecular sieve column 6.
One end of the solvent tank 10 is connected with a solvent source so that the solvent enters the solvent tank 10 after being fed, and the other end of the solvent tank 10 is communicated with the solvent storage tank 4 so that the solvent enters the solvent storage tank 4; the solvent tank 10 is also connected to a nitrogen source 7.
The outlet end of the solvent storage tank 4 is respectively connected with the inlet end of the first molecular sieve column 5 and the inlet end of the stirring tank 1 so that the solvent in the solvent storage tank can selectively enter the first molecular sieve column 5 or the stirring tank 1; the solvent storage tank 4 is connected with a vacuum pumping pump or a vacuum pumping pump group 8.
The outlet end of the first molecular sieve column 5 is connected with the inlet end of the solvent storage tank 4 so that the solvent passing through the first molecular sieve column 5 enters the solvent storage tank 4; the first molecular sieve column 5 is connected to a nitrogen gas source 7 so that the nitrogen gas pressure pushes the solvent flow in first molecular sieve column 5.
The outlet end of the solvent treatment tank 3 is respectively connected with the inlet end of the second molecular sieve column 6 and the inlet end of the storage tank 2 so that the solvent in the solvent treatment tank can selectively enter the second molecular sieve column 6 or the storage tank 2; the solvent treatment tank 3 is connected with a vacuum pumping pump or a vacuum pumping pump group 8.
The outlet end of the second molecular sieve column 6 is connected with the inlet end of the solvent treatment tank 3 so that the solvent passing through the second molecular sieve column 6 enters the solvent treatment tank 3; the second molecular sieve columns 6 are all connected with a nitrogen source 7.
The outlet end of the storage tank 2 is connected with the inlet end of the stirring tank 1 so that the liquid in the storage tank flows into a solvent treatment tank 3; the storage tank 2 is connected with a vacuum pump or a vacuum pump group 8.
The stirring tank 1 is provided with a feed inlet and an outlet end connected with the inlet end of the storage tank 2. The stirring tank 1 is connected with a nitrogen source 7; meanwhile, the stirring tank 1 is also connected with a vacuum pump or a vacuum pumping pump group 8.
The inlet of the mixing tank 1 is connected to a glove box 9, and a user generally needs to feed the materials in the glove box 9.
In a preferred embodiment, the first molecular sieve column 5 contains molecular sieves, including 4A molecular sieves, 3A molecular sieves, 5A molecular sieves, 10Z molecular sieves, 13Z molecular sieves, Y-type molecular sieves, MCM molecular sieves or ZSM molecular sieves, and more preferably 4A molecular sieves.
In a preferred embodiment, the second molecular sieve column 6 is provided with a modified molecular sieve therein. The modified molecular sieve comprises a modified 4A molecular sieve, a modified 3A molecular sieve, a modified 5A molecular sieve, a modified 10Z molecular sieve, a modified 13Z molecular sieve, a modified Y-type molecular sieve, a modified MCM molecular sieve or a modified ZSM molecular sieve and the like; more preferably a modified 4A molecular sieve.
In a preferred embodiment, the solvent tank 10, the first molecular sieve column 5, the second molecular sieve column 6 and the stirring tank 1 are respectively connected with the nitrogen source 7 through a pipeline A, a pipeline E, a pipeline K and a pipeline I.
The solvent storage tank 4, the solvent treatment tank 3, the storage tank 2 and the stirring tank 1 are respectively connected with a vacuum pumping pump or a vacuum pumping pump group 8 through a pipeline C, a pipeline O, a pipeline P and a pipeline H.
The solvent tank 10 is connected with the solvent storage tank 4 through a pipeline B; the outlet end of the solvent storage tank 4 is connected with the inlet end of the first molecular sieve column 5 through a pipeline D; the outlet end of the first molecular sieve column 5 is connected with the inlet end of the solvent storage tank 4 through a pipeline F; the outlet end of the solvent storage tank 4 is connected with the inlet end of the stirring tank 1 through a pipeline G.
The outlet end of the solvent treatment tank 3 is connected with the inlet end of a second molecular sieve column 6 through a pipeline J; the outlet end of the second molecular sieve column 6 is connected with the inlet end of the solvent treatment tank 3 through a pipeline L; the outlet end of the solvent treatment tank 3 is connected with the inlet end of the storage tank 2 through a pipeline M.
The outlet end of the storage tank 2 is connected with the inlet end of the stirring tank 1 through a pipeline N; the outlet end of the stirring tank 1 is connected with the inlet end of the solvent treatment tank 3 through a pipeline Q.
In this embodiment, a novel system is provided, first molecular sieve post 5 and second molecular sieve post 6 have been added to this system, and first molecular sieve post 5 can carry out treatments such as dewatering to the solvent to can carry out certain processing to additive or auxiliary agent in the electrolyte, make the electrolyte effect of preparing better.
Example 2
On the basis of the embodiment 1, the preparation method of the modified molecular sieve comprises the following steps: dissolving the modified compound in a solvent under a protective atmosphere, heating to a temperature near the boiling point of the solvent after complete dissolution, adding the molecular sieve powder into the solvent, adding an alkali such as sodium hydroxide, wherein the alkali can activate the silicon hydroxyl on the surface of the molecular sieve, the pH value is 8-9, stirring, reacting at the temperature for 0.5-2 hours, simultaneously refluxing, and filtering after the reaction is finished. The solvent in this stage may be methyl acetate, ethyl acetate, propyl acetate, toluene, and the like.
Then oxalic acid or acetic acid is added for washing, alkali, salt or impurities and the like which may be contained in the molecular sieve are removed, the structure of the molecular sieve which is not alkylated or silylated has certain acidity, the molecular sieve is dried for 10-20 hours (such as 10 hours, 12 hours, 14 hours, 15 hours, 18 hours and 20 hours) at 100-200 ℃ (such as 100 ℃, 120 ℃, 140 ℃, 150 ℃, 180 ℃ and 200 ℃), the surface structure is stable, and the acid treatment is favorable for assisting the auxiliary agent to carry out catalytic reaction. Washing with deionized water to remove free acid, salt or impurities, drying at 500 deg.C (300 deg.C, 350 deg.C, 400 deg.C, 450 deg.C, 480 deg.C, 500 deg.C) at 300 deg.C to completely solidify the molecular sieve structure, and drying at 5-8 deg.C/min (5 deg.C/min, 6 deg.C/min, 7 deg.C/min, 8 deg.C/min) without any influence on the microstructure or molecular sieve stability.
Preferred embodiments, for purposes of this application, modified molecular sieves prepared using 4A molecular sieves and the like, are generally good at adsorbing impurities in solvents and are beneficial for some of the adjuvant raw materials, such as potassium ferrocyanide and ferric sulfate, to form prussian blue, as further described in the examples below.
In a preferred embodiment, the modifying compound is an alkyl compound or a silane compound.
In a preferred embodiment, the alkyl compound comprises t-butyl chloride, chloropropane, ethyl chloride, benzyl chloride.
In a preferred embodiment, the silane compound is silane or disilane, in which at least one halogen atom, such as chlorine, bromine, etc., is directly attached to silicon, and at least one first group is further directly attached to silicon, and the first group includes tert-butyl, phenyl, phenol or phenyl with alkyl/nitro/alkoxy substituents, such as tri-tert-butylchlorosilane, di-tert-butylethylchlorosilane, di-tert-butylmethylchlorosilane, diphenylmonomethylchlorosilane, p- (tert-butyl) phenylethyldimethylchlorosilane, diphenyltriethylmonochlorosilane, phenyldimethylchlorosilane, etc., and it has been found that if all silanes are small molecular groups (such as methyl, etc.), the modified molecular sieve has relatively strong adsorption capacity, and when in use, the requirements on flow rate, temperature and pressure are required, and relatively speaking, the conditions are strict, and as a result, the controllability is not strong, and the comprehensive effect is better when 2-3 large groups such as tertiary butyl, phenyl and the like are carried in the silane.
In a preferred embodiment, the addition amount of the modifying compound is 1/30-1/10 of the mass of the molecular sieve raw material, for example 1/20, too much is not beneficial to the catalytic reaction of the auxiliary agent in the later period, and too little is too large the prussian blue production amount, or has certain adsorption capacity for the auxiliary agent of the application.
Example 3
On the basis of embodiment 1 or 2, a method for preparing an electrolyte comprising an organic solvent, a salt and an additive component, the additive component comprising an additive and an auxiliary agent; the method comprises the following steps:
(1) solvent entering solvent tank 10: the organic solvent at the solvent source enters the solvent tank 10;
(2) the solvent enters the solvent storage tank 4 from the solvent tank 10: opening a nitrogen gas valve, enabling high-purity nitrogen gas flow to enter a solvent tank 10 through a pipeline A, installing a one-way valve and a flowmeter on the pipeline A, enabling the gas flow pressure to be 0-0.6 MPa, and conveying the organic solvent to a solvent storage tank 4 through a pipeline B and a valve by using the nitrogen gas pressure;
simultaneously opening a valve, vacuumizing the solvent storage tank 4 through a pipeline C, configuring a weighing wagon balance for the solvent storage tank 4, and setting the total weight;
(3) first molecular sieve column 5 treatment: opening a valve at the bottom of a solvent storage tank 4, conveying the organic solvent in the solvent storage tank 4 into a first molecular sieve column 5 through a three-way valve and a pipeline D by a magnetic pump, simultaneously introducing high-purity nitrogen flow through a pipeline E and the valve, allowing the organic solvent to flow through the first molecular sieve from bottom to top under the action of the nitrogen flow, removing moisture, and then returning the organic solvent to the solvent storage tank 4 through a pipeline F and the valve to finish one-time water removal operation; the valve at the bottom of the solvent storage tank 4 can be used for taking the organic solvent 1 in the solvent storage tank 4 to detect the water content of the organic solvent.
(4) Entering a stirring tank 1 from a solvent storage tank 4: the organic solvent in the step (3) can be circularly removed in the first molecular sieve column 5 for a plurality of times, when the moisture content of the solvent is reduced to a specified value (such as <15 ppm), the three-way valve is adjusted, so that the organic solvent in the solvent storage tank 4 is conveyed to the operation end of the stirring tank 1 through the valve, the magnetic pump, the three-way valve and the pipeline G, and is injected into the stirring tank 1 through the valve.
(5) Adding an auxiliary raw material into a solvent, and conveying the solvent to a solvent treatment tank 3: before the organic solvent is injected into the stirring tank 1, the stirring tank 1 is first vacuumized through the pipe H. After the solvent is injected, an operator feeds the auxiliary raw materials into the stirring tank 1 through the feed inlet shutoff valve in proportion in the glove box 9 to be mixed and stirred with the solvent at the rotating speed: 0-100 rpm, paddle type: anchor oar + impulse type, the material: SS304 to obtain a solution.
After stirring, high-purity argon is injected into the stirring tank 1 through the pipeline I, a one-way valve at the bottom of the stirring tank 1 is opened, and the solution is transferred into the solvent treatment tank 3 through the pipeline Q by nitrogen pressure. The stirring tank 1 is provided with a temperature control system, the temperature of materials in the tank can be monitored in real time, the stirring tank 1 is provided with a jacket, cold water and hot water or other freezing media can be introduced, and the pressure resistance of the jacket is 0.4 MPa.
(6) And (3) treating in a second molecular sieve column 6: before the solution enters the solvent treatment tank 3, the solvent treatment tank 3 is vacuumized by a pipe O. After the solution enters, a valve at the bottom of the solvent treatment tank 3 is opened, the solution in the solvent treatment tank 3 is conveyed to a second molecular sieve column 6 through a three-way valve and a pipeline J by a magnetic pump, meanwhile, high-purity nitrogen flow is introduced through a pipeline K and the valve, the solution flows through the second molecular sieve column 6 from bottom to top under the action of the nitrogen flow, and then the solution returns to the solvent treatment tank 3 through a pipeline L and the valve; controlling the flow rate of the second molecular sieve to be 0.4V-3V L/min, such as 0.4V L/min, 0.5V L/min, 0.8V L/min, 1V L/min, 1.5V L/min, 1.8V L/min, 2V L/min, 2.5V L/min and 3V L/min; where V is the volume of molecular sieve in second molecular sieve column 6.
(7) Entering the storage tank 2 from the solvent treatment tank 3: before the solution enters the storage tank 2, the storage tank 2 is vacuumized through a pipeline P; the three-way valve is then adjusted so that the solution in the solvent treatment tank 3 is transferred to the storage tank 2 through the valve, the magnetic pump, the three-way valve and the pipe M.
(8) Conveyed from the storage tank 2 to the stirring tank 1: the one-way valve at the bottom of the storage tank 2 is opened, so that the solution in the storage tank 2 is conveyed to the stirring tank 1 through the valve, the magnetic pump and the pipeline N.
(9) Adding materials and stirring to finish preparation: before the solution is injected into the stirring tank 1, the stirring tank 1 is first vacuumized through the pipe H. After the solution is injected, the other components (the other components generally refer to lithium salt or lithium salt and additives, the additives herein refer to conventional additives, and generally do not include the additives described herein) to be added to the electrolyte are fed into the stirring tank 1 through the feed port shutoff valve in proportion by the operator in the glove box 9, and mixed and stirred with the solution at the following rotation speed: 0-100 rpm, paddle type: anchor oar + impulse type, the material: and an SS 304. After stirring, inject high-purity argon gas into agitator tank 1 by pipeline I to open the check valve of agitator tank 1 bottom, transfer electrolyte to annotate in the liquid machine through nitrogen pressure. The stirring tank 1 is provided with a temperature control system, the temperature of materials in the tank can be monitored in real time, the stirring tank 1 is provided with a jacket, cold water and hot water or other freezing media can be introduced, and the pressure resistance of the jacket is 0.4 MPa.
In a preferred embodiment, the molecular sieve in first molecular sieve column 5 is a commercially available conventional molecular sieve, as described in example 1. The molecular sieve in the second molecular sieve column 6 is a modified molecular sieve, as described in example 1 or 2, and is not described herein again.
In step (4), the organic solvent in the solvent storage tank 4 can be taken out, the water content of the organic solvent is detected, if the water content is high, the water can be circularly removed in the first molecular sieve column 5 for many times, and the water content of the solvent is reduced to a specified value (15 ppm). After passing through the second molecular sieve column 6, further water removal is also possible, typically to <10 ppm.
In a preferred embodiment, in step (5), the adjuvant raw materials include a yellow blood salt and a ferric salt, and the yellow blood salt and the ferric salt can partially generate the prussian blue.
In a preferred embodiment, in step (5), the auxiliary agents are sequentially added to the organic solvent, typically the xanthate is added first, and after dissolution, the ferric salt is added. The organic solvent added with the auxiliary agent is put into a second molecular sieve column 6, and the modified molecular sieve has certain catalytic assistance to Prussian blue generated by the xanthate and the ferric salt, and the generated amount is very small.
In the preferred embodiment, the flow rate through the second molecular sieve is typically controlled to 1.5V L/min. Of course, the flow rate can be determined according to the electrolyte composition, and is generally within the range described in step (6). The flow rate is important for the reaction of the catalyst promoter and, therefore, for the quality of the electrolyte product.
In a preferred embodiment, if there are multiple solvents, several sets of solvent tank, solvent storage tank and first molecular sieve column may be provided for the treatment, such as solvent (two) is treated by solvent tank (two), solvent storage tank (two) and first molecular sieve column (two), and solvent (three) is treated by solvent tank (three), solvent storage tank (three) and first molecular sieve column (three); the solvent tank (II) and the solvent tank (III) are also connected to the stirring tank 1. Whether the second molecular sieve treatment or the addition of an auxiliary agent, an additive component, a salt and the like is needed, and the like, and the specific operation can be carried out according to the type of the solvent and the actual requirement.
In a preferred embodiment, the organic solvent or solution in the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column is transported to the next step by the pressure of the protective gas. In the electrolyte preparation process, the vacuum degrees of the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are 0-50 KPa.
The acidity of the electrolyte prepared by the embodiment is controlled to be about 20 ppm; the water content is less than or equal to 10ppm, the acidity is less than or equal to 30ppm, and the turbidity is less than or equal to 3 NTU. The shelf life of the electrolyte prepared by the method is generally less than 6 months, and is preferably 1-2 months. The modified molecular sieve has weak adsorption to solvents, additives, auxiliaries and the like in the application and can be ignored.
The organic solvent of the invention adopts molecular sieve treatment, so the requirement of the application on the water content of the raw materials is low, the purchase of the raw materials is not strict, and the raw materials with low price can be selected.
Example 4
On the basis of example 3, the raw materials of the auxiliary agent are yellow blood salt and ferric salt, and the Prussian blue is generated by the yellow blood salt and the ferric salt when the yellow blood salt and the ferric salt pass through the modified molecular sieve and/or during the charging and discharging processes of the battery.
In a preferred embodiment, the auxiliary agent is 0.1 to 1%, preferably 0.15 to 0.7%, such as 0.15%, 0.2%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7% of the total electrolyte mass. The molar ratio of the addition amount of the xanthate to the trivalent ferric salt is 1 (1-2), such as 1: 1, 1: 1.5 and 1: 2.
In a preferred embodiment, the electrolyte of the present application contains prussian blue in an amount of 0 to 0.5%, preferably 0.05 to 0.15%, such as 0.05%, 0.1%, 0.15% by mass of the whole electrolyte, and the amount of prussian blue is not higher than the amount of the added xanthate or ferric salt. As the system, the conditions, the raw materials and the like in the application are all the optimal conditions for non-synthesis of Prussian blue, the auxiliary agents in the system can not be completely converted into Prussian blue, and are basically within 0.5 percent, and the final amount of the electrolyte prepared according to the process and the amount in the application is basically 0.05 to 0.15 percent.
In a preferred embodiment, the xanthate comprises at least one of potassium xanthate, lithium xanthate and sodium xanthate; the ferric salt comprises at least one of ferric sulfate, ferric carbonate and ferric chloride; preferably, the xanthate is potassium xanthate, lithium xanthate or sodium xanthate; the ferric salt is ferric sulfate or ferric carbonate. It has been found by practice that in the system of the present application these components are capable of forming prussian blue in part, but not in whole, in particular iron sulphate, the results obtained being optimal for the present application.
In a preferred embodiment, when the electrolyte is used, i.e. during charging and discharging, the prussian blue and the auxiliary raw material dissolved in the electrolyte are partially precipitated as prussian blue, which is a cell-shaped structure. The production of the Prussian blue in the application can help to improve the uniformity and stability of the interface film on the surface of the electrode, and a compact film can be formed more easily through the structural coordination of the crystal cell structure, the residual auxiliary agent, the additive, the metal ions and the like, so that the stability of the whole body, the capacity of a battery and the like are benefited.
In a preferred embodiment, the organic solvent solution added with the auxiliary agent is an organic solvent solution after molecular sieve treatment, and preferably a modified molecular sieve is used. See the examples below for methods of modification.
The electrolyte can be used for preparing button batteries, cylindrical batteries, soft package batteries, square batteries and the like. The additive in the embodiment has the advantages of easily obtained raw materials, low cost and good effect, and can be used as a novel additive. In addition, the molecular sieve treatment is adopted in the embodiment, so the requirement of the application on the water content of the raw material is low, the purchase of the raw material is not strict, and the raw material with low price can be selected. In addition, in the present example, under the conditions of the present invention, prussian blue was produced from 20 to 70% of the auxiliary, generally about 35 to 60%.
The auxiliary agent in the embodiment has the advantages of easily available raw materials, low cost and good effect, and can be used as a novel additive.
Example 5
In addition to examples 3 and 4, the above-mentioned additives are preferably carbonate additives, such as fluoroethylene carbonate (FEC) and Vinylene Carbonate (VC), and may be boron-containing additives such as Tetramethylborate (TMB), Trimethyl Borate (TB), tris (trimethylsilane) borate (TMSB), and trimethylcyclotriboroxane.
In preferred embodiments, the salts include lithium, potassium, and sodium salts, such as lithium hexafluorophosphate LiPF6Lithium tetrafluoroborate (LiBF)4Lithium bis (oxalato) borate LiBOB, lithium difluorophosphate LiDFP, lithium difluorooxalato borate LiDFOB or LiODFB, lithium difluorooxalato phosphate LiDFOP, lithium tetrafluorooxalato phosphate LiTFOP, lithium tris (oxalato) phosphate LiTOP, lithium bis (trifluoromethylsulfonyl) imide LiTFSI, lithium bis (fluorosulfonyl) imide LiFSI, lithium carbonate Li2CO3And lithium fluoride, and the lithium in this case may be adjusted to potassium, sodium, or the like as needed.
The organic solvent comprises at least one of dimethyl carbonate, methyl ethyl carbonate, ethyl acetate, methyl propionate and ethyl propionate solvents.
In this embodiment, the additive can be used as an additive component of an electrolyte in combination with an additive, and the electrolyte prepared by the method of the present invention has excellent effects.
Example 6
A battery as in any one of embodiments 3 to 5, comprising a positive electrode, a negative electrode, a separator disposed between the positive and negative electrodes, and the electrolyte as described in any one of embodiments 1 to 5.
The positive electrode, the negative electrode, and the separator may be made of any materials that are conventional in the art, for example, the positive electrode may be made of lithium cobaltate, a ternary material, or a lithium-rich manganese-based material, the negative electrode may be made of metal lithium, a lithium-based composite material (e.g., lithium-carbon, lithium-silicon-carbon, lithium-SiOx-carbon), and the separator may be a polyethylene film, a polypropylene film, or the like.
Example 7
Preparation of modified molecular sieves: under the protection atmosphere, adopting ethyl acetate (which can be replaced by toluene) to dissolve 0.6kg of tri-tert-butylchlorosilane, heating to the vicinity of the boiling point of the solvent after complete dissolution, adding 10kg of 4A molecular sieve powder into the solvent, adding sodium hydroxide to enable the pH value to be 8.5, stirring, reacting for 1.5 hours at the temperature, simultaneously refluxing, and filtering after the reaction is finished. Then adding 1L oxalic acid for washing, drying at 150 ℃ for 15 hours, washing with deionized water, heating to 400 ℃ at the speed of 6 ℃/min, drying for 5 hours, washing with ethanol once, hot-pressing at 150 ℃, and drying to obtain the modified 4A molecular sieve.
10L of ethyl methyl carbonate (water content: 34ppm) as an organic solvent was charged, and the material was pressure-fed into a solvent tank by means of nitrogen. Then opening a nitrogen gas valve, enabling high-purity nitrogen gas flow to enter a solvent tank through a pipeline A, installing a one-way valve and a flowmeter on the pipeline A, enabling the gas flow pressure to basically float around 0.3 MPa, and conveying the organic solvent to a solvent storage tank through a pipeline B and a valve by the nitrogen pressure; while conveying, opening a valve, and vacuumizing the solvent storage tank through a pipeline C; then opening a valve at the bottom of the solvent storage tank, conveying the organic solvent in the solvent storage tank into the first molecular sieve column through a three-way valve and a pipeline D by a magnetic pump, simultaneously introducing high-purity nitrogen flow through a pipeline E and the valve, allowing the organic solvent to flow through the first molecular sieve from bottom to top under the action of the nitrogen flow, removing moisture, and then returning the organic solvent to the solvent storage tank through a pipeline F and the valve to finish primary water removal operation; the valve at the bottom of the solvent storage tank can be used for taking the organic solvent 1 in the solvent storage tank to detect the water content of the organic solvent, and the water content is 14 ppm. Then, the three-way valve is adjusted so that the organic solvent in the solvent storage tank is transported to the operation end of the stirring tank through the magnetic pump, the three-way valve and the pipeline G, and is injected into the stirring tank through the valve. Before the organic solvent is injected into the stirring tank, the stirring tank is first vacuumized through a pipeline H. After the solvent is injected, feeding the auxiliary raw materials into a stirring tank through a feed inlet shutoff valve by an operator in a glove box according to a proportion, and mixing and stirring the auxiliary raw materials with the solvent at a rotating speed: 40 rpm, paddle type: anchor oar + impulse type, the material: SS304 to obtain a solution. After stirring, high-purity argon is injected into the stirring tank through a pipeline I, a one-way valve at the bottom of the stirring tank is opened, and the solution is transferred into the solvent treatment tank through a pipeline Q by nitrogen pressure. Before the solution enters the solvent treatment tank, the solvent treatment tank is vacuumized through a pipeline O. After the solution enters, a valve at the bottom of the solvent treatment tank is opened, the solution in the solvent treatment tank is conveyed to a second molecular sieve column through a three-way valve and a pipeline J by a magnetic pump, meanwhile, a high-purity nitrogen flow is introduced through a pipeline K and the valve, the solution flows through the second molecular sieve column from bottom to top under the action of the nitrogen flow, and then the solution returns to the solvent treatment tank through a pipeline L and the valve, wherein the water content is 8 ppm; the flow rate through the second molecular sieve was controlled at 1.5V L/min. Before the solution enters the storage tank, the storage tank is vacuumized by a pipeline P; the three-way valve is then adjusted so that the solution in the solvent treatment tank is delivered to the holding tank through the valve, magnetic pump, three-way valve and line M. And opening a one-way valve at the bottom of the storage tank, so that the solution in the storage tank is conveyed into the stirring tank through the valve, the magnetic pump and the pipeline N. Before the solution is injected into the stirring tank, the stirring tank is vacuumized by a pipeline H, and the vacuum degree is kept in dynamic balance of 30-50 KPa. After the solution is injected, an operator adds lithium salt and an additive in a glove box, the lithium salt is added according to the amount of 1 mol per liter of solvent, and after the solution is completely stirred, the electrolyte is transferred to an electrolyte injection machine through nitrogen pressure to obtain the electrolyte. The above operations are all carried out at normal temperature.
Then, the electrolyte, the positive electrode, the negative electrode and the diaphragm are made into a soft package battery according to a conventional method, and in the batteries of the following test examples, other components and contents are the same, namely, the positive electrode is lithium cobaltate, the negative electrode is lithium-carbon, the diaphragm is a polyethylene film, and the lithium salt is lithium bis (trifluoromethylsulfonyl) imide. The difference points are only described in the following experimental examples and comparative examples, and then room temperature cycle tests were performed on the experimental examples and comparative examples, and the main results are shown in table 1. The moisture content of the raw materials used in this example were all <50 ppm.
Experimental example: the auxiliary agent is added with the raw materials of lithium ferrocyanide and ferric sulfate, the mass of the auxiliary agent is 0.4 percent of the mass of the electrolyte, and the molar ratio of the lithium ferrocyanide to the ferric sulfate is 1: 2; the additive is FEC, and the mass of FEC is 0.4% of the mass of electrolyte;
comparative example: the organic solvent ethyl methyl carbonate is directly added into a stirring tank, then the auxiliary agent, the additive, the salt and the like are added into the stirring tank from a glove box, the specific type and the addition amount are consistent with those of the experimental example, and the operation is carried out at normal temperature.
Coulombic efficiency and capacity retention ratio (0.1C/0.1C 100 weeks) of the experimental examples and the comparative examples were measured, and the results are shown below.
As can be seen from the above, the first coulombic efficiency of the battery and the capacity retention rate of the battery are significantly reduced because the same raw materials and the like are not used in the method of the present application.
Example 8
The action of the auxiliaries in the present application is further illustrated by the following test examples, using the method in example 7.
Test example 1: in agreement with the experimental example in example 7;
test example 2: adding an auxiliary agent without adding an additive, wherein the auxiliary agent is added raw materials of lithium ferrocyanide and ferric sulfate, the mass of the auxiliary agent is 0.8% of the mass of the electrolyte, and the molar ratio of the lithium ferrocyanide to the ferric sulfate is 1: 2;
test example 3: adding an additive without an auxiliary agent, wherein the additive is FEC, and the mass of the FEC is 0.8% of that of the electrolyte;
test example 4: no additives and auxiliaries are added.
Test example 5: the mass of the Prussian blue added is 0.8 percent of the mass of the electrolyte, and other additives and additives are not added.
Test example 6: the mass of the added lithium xanthate accounts for 0.8 percent of the mass of the electrolyte, and other additives and additives are not added.
Test example 7: the weight of the added ferric sulfate is 0.8 percent of the weight of the electrolyte, and other auxiliary agents and additives are not added.
In addition, for the experimental examples 1 to 3, the thin film on the surface of the electrode is obviously formed, and the experimental examples 1 and 2, prussian blue is obviously concentrated in the thin film on the surface of the electrode, and the uniformity of the film is better, the transmission diagram of the surface of the positive electrode of the experimental example 1 is shown in fig. 2, the experimental example 2 is shown in fig. 3 and 4, the number of nanometer units in the diagram is a scale, the thin film with good uniformity is obviously provided in the diagram, and the inner side of the thin film is the electrode. As shown in fig. 5 and 6 for the negative electrode SEM images of test example 1, fig. 7 and 8 for the negative electrode SEM images of test example 2, and fig. 9 and 10 for the negative electrode SEM images of test example 3, it can be seen that all of test examples 1 to 3 are excellent in effect, the surface of lithium metal is flat after many charge and discharge cycles, lithium dendrites hardly appear on the surface of test example 1, lithium dendrites hardly appear on the surfaces of fig. 7 and 8, and lithium dendrite phenomenon hardly appears in fig. 9. The film contains Prussian blue, carbonate, ferrocyanide, sulfate, methoxide, lithium ethoxide, carbon monoxide, methane, ethane, etc. The thin film formation was not evident in test examples 4 to 7. In addition, in test example 5, prussian blue was additionally added, which has poor solubility in the organic solvent system of the present application, requires heating and stirring for a long time, and is not dissolved partially, and during charging and discharging, it was not significantly concentrated on the electrode surface to form a thin film, and after many cycles, severe lithium dendrites appeared on the electrode surface, as shown in fig. 11. Further, test examples 6 and 7 also exhibited severe lithium dendrites, and the test is shown in fig. 12, for example.
From the above, the additive in the application has a good effect, and basically keeps the level of the additive in the prior art. Furthermore, it was found from the cycling curves that the cell made in test example 1 exhibited a distinct and stable interfacial film on the electrode surface after the first cycle of cycling. But none of the test examples 4 to 7.
In addition, the addition of the additive and/or the auxiliary agent in the solution improves the interface stability of the lithium metal cathode, simultaneously contributes to promoting the uniform deposition of Li & lt + & gt on the surface of the cathode, inhibits the growth of lithium dendrites, and ensures that the surface of the lithium metal is smooth after multiple charge-discharge cycles without obvious lithium dendrites and the battery is safer.
Example 9
The test example 2 of example 8 was subjected to 4A molecular sieve treatment, 4A molecular sieve modified in the present application (purchased from carbofuran), and no molecular sieve treatment, respectively, and then tested for performance, with the results shown below.
From the above results, although the battery performance is improved to a greater or lesser extent in all three cases, the thin film is more easily dense and uniform by the modified molecular sieve treatment, and the first coulombic efficiency and the capacity retention rate are both good. And only through the treatment of the molecular sieve purchased in the market without modification or the treatment of the molecular sieve, the composite membrane is not easy to form an interface membrane and an interface film, and has uneven thickness and poorer comprehensive effect.
Example 10
In test example 1 of example 8, if each of the molecular sieves modified with benzyl chloride and chlorotrimethylsilane was used, the results obtained are as follows, except that the conditions were the same as those of example 8. The comprehensive effect of the trimethylchlorosilane is poor.
In the application, when the organic solvent containing the auxiliary raw material passes through the modified molecular sieve, a small amount of Prussian blue is generated under the catalysis of the modified molecular sieve, is generated in situ in the solvent, is small in amount, and can be excellently fused with the solvent into a whole. In the charging and discharging process, the obvious Prussian blue appears in the electrolyte, namely part of Prussian blue is further generated by the aid raw material in the electrolyte, the Prussian blue is separated out on the electrolytic surface in the charging and discharging process, the Prussian blue molecules generated in the charging and discharging process are similar to unit cell-shaped molecules and can be uniformly distributed on the surface of an electrode, and other components can be positioned in or out of the electrode, so that the film uniformity is good, and the overall effect of the battery is good. In the prior art, the Prussian blue is only used for preparing the electrode and is only in a research stage, and the Prussian blue is indirectly used in the electrolyte and is matched with the auxiliary raw materials and other components of the electrolyte to improve the overall effect.
The method avoids the defects of poor dissolubility, poor effect and the like caused by directly adding the Prussian blue by adding the raw material auxiliary agent.
Finally, it should be noted that: the above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. A preparation method of electrolyte is characterized by comprising the following steps: the electrolyte comprises an organic solvent, salt and an additive component, wherein the additive component comprises an additive and/or an auxiliary agent; the method comprises the following steps:
(1) the organic solvent enters a solvent tank;
(2) the organic solvent enters a solvent storage tank from a solvent tank;
(3) conveying the organic solvent in the solvent storage tank to a first molecular sieve column, returning the organic solvent to the solvent storage tank after flowing out of the first molecular sieve column, and testing the water content of the organic solvent; if the water content in the organic solvent is more than 15 ppm, the organic solvent can be circularly removed in the first molecular sieve column for a plurality of times until the water content of the organic solvent is reduced to less than 15 ppm;
(4) conveying the organic solvent in the solvent storage tank to a stirring tank;
(5) feeding the auxiliary agent into a stirring tank in a glove box, and mixing and stirring the auxiliary agent and the organic solvent to obtain a solution; after stirring, transferring the solution into a solvent treatment tank;
(6) after entering the solvent treatment tank, the solution is conveyed into the second molecular sieve column from the solvent treatment tank, flows out of the second molecular sieve column and returns to the solvent treatment tank; controlling the flow rate of the second molecular sieve column to be 0.4V-3V L/min, wherein V is the volume of the molecular sieve in the second molecular sieve column;
(7) conveying the solution treated in the solvent treatment tank in the step (6) to a storage tank;
(8) the solution is conveyed into the stirring tank from the storage tank;
(9) after the solution is injected into a stirring tank, adding the raw materials except the auxiliary agent and the organic solvent in the electrolyte into the stirring tank in a glove box, and mixing and stirring the raw materials and the solution to obtain an electrolyte;
the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column are all independently connected with a protective gas source; the organic solvents or solutions in the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column are all conveyed to the next step by the pressure of protective gas; the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are all independently connected with a vacuum pumping pump; in the electrolyte preparation process, the vacuum degrees of the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are 0-50 KPa.
2. The method for preparing the electrolyte according to claim 1, characterized in that: the molecular sieve in the second molecular sieve column is a modified molecular sieve;
the flow rate of the solution through the second molecular sieve column was controlled at 1.5V L/min.
3. The method for preparing the electrolyte according to claim 1, characterized in that: the raw materials of the auxiliary agent comprise yellow blood salt and ferric iron salt, wherein the yellow blood salt and the ferric iron salt can partially generate Prussian blue.
4. The method for preparing the electrolyte according to claim 1, characterized in that: the additive comprises a carbonate additive;
the salt comprises lithium salt, potassium salt and sodium salt;
the organic solvent comprises at least one of dimethyl carbonate, methyl ethyl carbonate, ethyl acetate, methyl propionate and ethyl propionate solvents.
5. The method for preparing the electrolyte according to claim 2, characterized in that: the preparation method of the modified molecular sieve comprises the following steps: dissolving the modified compound in a solvent under a protective atmosphere, heating to the boiling point of the solvent after complete dissolution, adding molecular sieve powder into the solvent, adding alkali, stirring, reacting at the temperature of the boiling point of the solvent for 0.5-2 hours, and performing suction filtration after the reaction is finished;
washing with weak acid for 1-3 times after suction filtration, and drying at 200 ℃ for 10-20 hours; washing with water for 1-2 times, drying at 500 deg.C for 3-6 hr, washing with alcohol, hot pressing at 200 deg.C, and drying to obtain the modified molecular sieve.
6. The method for preparing the electrolyte according to claim 5, characterized in that: the solvent is at least one of methyl acetate, ethyl acetate, propyl acetate and toluene;
after rinsing with water, the drying temperature is raised by 5 to 8 ℃/min.
7. The method for preparing the electrolyte according to claim 5, characterized in that: the modified molecular sieve is a modified 4A molecular sieve, a modified 3A molecular sieve, a modified 5A molecular sieve, a modified 10Z molecular sieve, a modified 13Z molecular sieve, a modified Y-type molecular sieve, a modified MCM molecular sieve or a modified ZSM molecular sieve;
the modified compound is an alkyl compound or a silane compound.
8. An electrolyte preparation system, its characterized in that: the system for preparing the electrolyte of any one of claims 1-7, the system comprising: at least one solvent tank, at least one solvent storage tank, at least one solvent treatment tank, at least one holding tank, at least one agitation tank, at least one first molecular sieve column, and at least one second molecular sieve column;
one end of the solvent tank is connected with a solvent source so that a solvent enters the solvent tank after being fed, and the other end of the solvent tank is communicated with the solvent storage tank so that the solvent enters the solvent storage tank;
the outlet end of the solvent storage tank is respectively connected with the inlet end of the first molecular sieve column and the inlet end of the stirring tank so that the solvent in the solvent storage tank can selectively enter the first molecular sieve column or the stirring tank;
the outlet end of the first molecular sieve column is connected with the inlet end of the solvent storage tank so that the solvent passing through the first molecular sieve column enters the solvent storage tank again;
the outlet end of the solvent treatment tank is respectively connected with the inlet end of the second molecular sieve column and the inlet end of the storage tank so that the solvent in the solvent treatment tank can selectively enter the second molecular sieve column or the storage tank;
the outlet end of the second molecular sieve column is connected with the inlet end of the solvent treatment tank so that the solvent passing through the second molecular sieve column enters the solvent treatment tank again;
the outlet end of the storage tank is connected with the inlet end of the stirring tank so that the solution in the storage tank flows into the stirring tank;
the solvent tank, the stirring tank, the first molecular sieve column and the second molecular sieve column are all independently connected with a protective gas source; the solvent storage tank, the solvent treatment tank, the storage tank and the stirring tank are all independently connected with a vacuum pumping pump.
9. The electrolyte preparation system of claim 8, wherein: the stirring tank is provided with a feed inlet, and the feed inlet is connected with the glove box so that feeding can be carried out in the glove box;
a 4A molecular sieve is arranged in the first molecular sieve column; the molecular sieve in the second molecular sieve column is the modified molecular sieve of any one of claims 2 or 5 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110408556.4A CN112838271B (en) | 2021-04-16 | 2021-04-16 | Preparation method and preparation system of electrolyte |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110408556.4A CN112838271B (en) | 2021-04-16 | 2021-04-16 | Preparation method and preparation system of electrolyte |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112838271A CN112838271A (en) | 2021-05-25 |
| CN112838271B true CN112838271B (en) | 2021-07-06 |
Family
ID=75929841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110408556.4A Active CN112838271B (en) | 2021-04-16 | 2021-04-16 | Preparation method and preparation system of electrolyte |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112838271B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101759246A (en) * | 2010-01-15 | 2010-06-30 | 马军 | Method for treatment of waste water containing organic solvents and treatment device |
| CN103378370A (en) * | 2012-04-24 | 2013-10-30 | 张家港市国泰华荣化工新材料有限公司 | Lithium iodide organic electrolyte for lithium iron battery and preparation method thereof |
| CN108288728A (en) * | 2018-01-23 | 2018-07-17 | 广东卡达克汽车科技有限公司 | It is a kind of adaptation silicon carbon material lithium-ion battery electrolytes and its application |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102050458B (en) * | 2009-10-30 | 2012-08-08 | 中国石油天然气股份有限公司 | Modified molecular sieve capable of improving sodium pollution resisting capability and preparation method of modified molecular sieve |
-
2021
- 2021-04-16 CN CN202110408556.4A patent/CN112838271B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101759246A (en) * | 2010-01-15 | 2010-06-30 | 马军 | Method for treatment of waste water containing organic solvents and treatment device |
| CN103378370A (en) * | 2012-04-24 | 2013-10-30 | 张家港市国泰华荣化工新材料有限公司 | Lithium iodide organic electrolyte for lithium iron battery and preparation method thereof |
| CN108288728A (en) * | 2018-01-23 | 2018-07-17 | 广东卡达克汽车科技有限公司 | It is a kind of adaptation silicon carbon material lithium-ion battery electrolytes and its application |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112838271A (en) | 2021-05-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Ionothermal synthesis and lithium storage performance of core/shell structured amorphous@ crystalline Ni–P nanoparticles | |
| CA2875732A1 (en) | Method of manufacturing reaction agglomerated particles, method of manufacturing cathode active material for lithium ion battery, and method of manufacturing lithium ion battery containing cathode active material for lithium ion battery | |
| CN107628594B (en) | Solvothermal preparation method of 3D flower-shaped lithium iron phosphate cathode material assembled by two-dimensional nanosheets | |
| CN109962234B (en) | Concentration gradient single crystal anode material and preparation method thereof | |
| CN103187565B (en) | A kind of preparation method of the rich lithium Mn base anode material presomas of lithium ion battery | |
| CN111725564A (en) | Formation method of lithium ion battery | |
| CN115321507B (en) | Method for preparing ferric manganese phosphate by coprecipitation and application thereof | |
| JPH09245834A (en) | Electrolytic solution for lithium secondary battery | |
| WO2013111487A1 (en) | Method for manufacturing metallic agglomerated particles, method for manufacturing positive-electrode active material for lithium ion battery, method for manufacturing lithium ion battery, and lithium ion battery | |
| CN109167063A (en) | A kind of lithium anode and its preparation method and application of artificial solid electrolyte interface layer protection | |
| CN112838271B (en) | Preparation method and preparation system of electrolyte | |
| CN115650253A (en) | Spherical-like single crystal Prussian white positive electrode material, preparation method thereof and sodium ion battery | |
| CN104752720B (en) | A kind of iron manganese phosphate for lithium and its preparation method and application | |
| CN113213545B (en) | Spherical manganese iron carbonate and preparation method thereof | |
| JP2013151383A5 (en) | ||
| CN105489875A (en) | Preparation method of nickel-cobalt-manganese hydroxide for ternary polymer battery | |
| CN112803073B (en) | Additive, electrolyte and battery | |
| CN103258993B (en) | A kind of preparation method of the LiFePO 4 powder for anode material for lithium-ion batteries | |
| CN111689918B (en) | Functional diaphragm coating material for protecting lithium metal negative electrode and preparation method and application thereof | |
| CN105261737A (en) | Preparation method of ternary cathode material | |
| WO2024036906A1 (en) | Lithium-ion battery positive electrode material and preparation method therefor | |
| CN108808086B (en) | Lithium ion battery non-aqueous electrolyte and lithium ion battery | |
| CN106006723A (en) | Simple preparing method of lithium titanate | |
| CN106920961B (en) | Modification method of ternary material for lithium ion battery | |
| EP3503272B1 (en) | Active material for negative electrode, negative electrode piece, and secondary battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |