CN113871799B - Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery - Google Patents

Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery Download PDF

Info

Publication number
CN113871799B
CN113871799B CN202111254707.1A CN202111254707A CN113871799B CN 113871799 B CN113871799 B CN 113871799B CN 202111254707 A CN202111254707 A CN 202111254707A CN 113871799 B CN113871799 B CN 113871799B
Authority
CN
China
Prior art keywords
film layer
lithium
sulfur battery
battery
layer
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
Application number
CN202111254707.1A
Other languages
Chinese (zh)
Other versions
CN113871799A (en
Inventor
唐晶晶
高辛龙
杨娟
周向阳
邹建勋
梁家浩
苏帆雲
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Central South University
Original Assignee
Central South University
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Central South University filed Critical Central South University
Priority to CN202111254707.1A priority Critical patent/CN113871799B/en
Publication of CN113871799A publication Critical patent/CN113871799A/en
Application granted granted Critical
Publication of CN113871799B publication Critical patent/CN113871799B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)

Abstract

The invention belongs to the technical field of lithium-sulfur battery materials, and particularly relates to a lithium-sulfur battery functional diaphragm which comprises a first film layer and a second film layer, wherein a film gap exists between the first film layer and the second film layer; the second film layer comprises a polymer matrix, and lithium salt and additives distributed in the matrix, wherein the additives are Li 7‑x‑ 3y La 3 Zr 2‑x‑z A y B x C z O 12 . The invention also provides preparation and application of the material, and the prepared lithium-sulfur battery and the battery core thereof. According to the invention, PVDF-HFP is used as a matrix in the second film layer, and lithium salt and the additive are dispersed, and then the second film layer is combined with the first film layer, so that the second film layer is further matched with the first film layer in a clearance fit manner, the cooperation can be generated, the shuttle problem of polysulfide can be effectively improved, and the volume expansion effect can be relieved and the structural stability can be enhanced.

Description

Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery
Technical Field
The application belongs to the field of battery materials of lithium-sulfur batteries, and relates to a preparation method of a polymer interlayer material of a lithium-sulfur battery, and the preparation method is applied to the lithium-sulfur battery.
Background
With the increasing demand in the energy field, the development of energy storage devices with high energy density, new energy markets have increased the demand for electrochemical energy storage devices. However, the lithium ion battery with the widest current application range has the defects of insufficient energy density and high cost, so that the development of energy storage equipment with high power density, high energy density and low cost is critical.
Lithium sulfur batteries are considered to be the most likely next generation commercial large-scale energy storage system due to their high theoretical specific capacity (1675 mAh/g) and theoretical energy density (2600 Wh/kg) that are of interest, while elemental sulfur is inexpensive and environmentally friendly.
However, lithium sulfur batteries still have some drawbacks, (1) elemental sulfur as a positive electrode material has low electron conductivity, and the poor conductivity itself limits the application of the active material, thus resulting in low specific discharge capacity and low rate capability. (2) The shuttle effect, during the charge and discharge of lithium sulfur batteries, can generate a large amount of intermediate products, namely lithium polysulfide, and meanwhile, the lithium polysulfide can have higher solubility in ether electrolyte, so that a large amount of active substances are irreversibly lost and the coulombic efficiency is low. (3) The volume expansion, because the sulfur can generate insoluble lithium sulfide in the charging process, the density of the lithium sulfide is smaller than that of the sulfur, the volume expansion occurs at the positive electrode, the volume expansion rate can reach 80% at maximum, and the cycle performance of the battery is influenced to a certain extent.
In order to solve the problems, researchers put forward a multi-layer and multi-angle solution, and the problem of poor conductivity can be solved by compounding elemental sulfur with a carbon material with better conductivity, so that the volume expansion can be relieved to a certain extent by improving the pore structure of the carbon material, and the shuttle effect is restrained by adopting a mode of loading nitrogen on a positive electrode material and the like through physical adsorption or chemical adsorption. However, these problems still remain to be solved completely, or the preparation method is difficult and is not easy to prepare in large scale.
Disclosure of Invention
In order to solve the defects in the prior art, a first object of the invention is to provide a lithium sulfur battery functional separator, which aims to improve shuttle and structure stability of polysulfide of a lithium sulfur battery.
The second object of the invention is to provide a method for preparing the functional membrane.
The third object of the present invention is to provide a lithium-sulfur battery cell, a lithium-sulfur battery, and an assembling method thereof, which are equipped with the functional separator.
A lithium sulfur battery functional diaphragm comprises a first film layer and a second film layer, wherein a film gap exists between the first film layer and the second film layer;
the second film layer comprises a polymer matrix, and lithium salt and additives distributed in the matrix, wherein the additives are compounds with chemical expression of formula 1:
Li 7-x-3y La 3 Zr 2-x-z A y B x C z O 12 ；
1 (1)
Wherein A is selected from at least one of Al, ga and Nb, B is selected from at least one of Ta and Nb, and C is selected from at least one of Ge and Ti; x is more than 0 and less than or equal to 1, y is 0-0.4, and z is 0-1;
the polymer matrix material of the second membrane layer is PVDF-HFP.
According to the invention, PVDF-HFP is used as a matrix in the second film layer, and lithium salt and the additive are dispersed, and then the second film layer is combined with the first film layer, so that the second film layer is further matched with the first film layer in a clearance fit manner, the cooperation can be generated, the shuttle problem of polysulfide can be unexpectedly improved, and the volume effect and the structural stability can be relieved. According to research, through the synergistic combination of the substance and the structural functional membrane, various performances of the lithium-sulfur battery, such as capacity, multiplying power and cycling stability, can be effectively improved.
In the invention, the first film layer is a polymer film layer;
preferably, the polymer of the first film layer is at least one of polypropylene, polyethylene oxide and polyvinylidene fluoride;
preferably, the thickness of the first film layer is 20-40 μm, preferably 25-38 μm. The porosity is preferably 35 to 45%, preferably 39 to 45%, and the average pore diameter is preferably 0.028 to 0.043. Mu.m.
According to the invention, PVDF-HFP is used as a matrix of the second film layer, so that the PVDF-HFP can be cooperated with an additive and lithium salt in the film, the cooperativity of the first film layer in clearance fit can be further improved, and the performance of the PVDF-HFP in a lithium-sulfur battery can be further improved.
In the present invention, the molecular weight of PVDF-HFP is not particularly limited, and may be, for example, 30 to 50 ten thousand, preferably 40 to 45.5 ten thousand, which satisfies the film-forming requirement.
The research of the invention also discovers that the control of the lattice hybridization type and the content of the additive is helpful to further improve the synergistic effect of the first film layer and the second film layer.
In the additive, the x is preferably 0.2-0.8; more preferably 0.4 to 0.6. Y is preferably 0 to 0.4; more preferably 0.2 to 0.4. The preferable range is 0 to 0.5; more preferably 0 to 0.2.
Preferably, in the additive, B comprises Ta, wherein x is 0.4 to 0.6, and y and z=0.
Preferably, a comprises Al and B comprises Ta; wherein x is 0.4-0.6, y is 0.2-0.4, and z is 0. It has been unexpectedly found that by Ta and Al double site lattice hybridization, it helps to further unexpectedly improve the electrochemical performance of the resulting material in lithium sulfur batteries.
The additive can be obtained based on mixed ball milling sintering of raw materials of elements. For example, the raw material of each element is at least one of an oxide, hydroxide, carbonate, organic acid salt (such as acetate) and nitrate of each element. The elements are fed according to the stoichiometric ratio. The ball milling is, for example, dry ball milling or wet ball milling. The firing temperature is, for example, 850 to 1150℃and preferably 900 to 1000 ℃. The sintering time is, for example, 5 to 20 hours, preferably 6 to 10 hours. The sintered material can be further subjected to ball milling activation treatment.
Preferably, in the second film layer, the lithium salt is one or more of lithium bis (trifluoromethylsulfonyl) imide, lithium difluoromethyl imide and lithium tetrafluoroborate; LITFSI is preferred.
Preferably, the content of lithium salt in the second film layer is 30-50wt%; the content of the additive is 5-15 wt%.
Preferably, the thickness of the second film layer is 10 to 45 μm, preferably 20 to 40 μm. The porosity is preferably 30% -45%, and the average pore diameter is preferably 0.030-0.056 μm.
In the invention, the first film layer and the second film layer are mutually independent.
In the invention, the membrane gap can infiltrate electrolyte.
Preferably, the first film layer and the second film layer are laminated.
The invention also provides a preparation method of the lithium-sulfur battery functional diaphragm, which is used for obtaining a first film layer and a second film layer; and then superposing the first film layer and the second film layer to obtain the adhesive.
In the invention, the second film layer and the first film layer are independently formed into films, and then are overlapped to obtain the functional diaphragm. The invention discovers that the clearance fit functional membrane obtained by the method can unexpectedly further improve the synergistic effect between the first membrane layer structure and the additive and can unexpectedly further improve the electrochemical performance of the prepared material in a lithium-sulfur battery.
In the present invention, the first film layer and the second film layer may be formed independently based on the existing means. For example, the respective film layers may be formed by coating or the like.
For example, the preparation process of the second film layer is as follows: and adding PVDF-HFP into a solvent for dissolution, adding lithium salt and an additive, stirring uniformly, removing bubbles, then placing on a template with a flat surface, rounding by means of the surface tension of the polymer solution, and vacuum drying to obtain a second film layer. The organic solvent used for slurrying is a solvent capable of dissolving the polymeric substrate, e.g., including one or more of acetone, acetonitrile, butanone, N-methylpyrrolidone.
In the present invention, the first film layer may be a commercially available separator product.
The invention also provides a lithium sulfur battery cell structure, which comprises an anode, a cathode and a diaphragm for dividing the anode and the cathode, wherein the diaphragm is the functional diaphragm, and the second diaphragm layer is close to the anode side.
According to the invention, the electrochemical performance of the lithium-sulfur battery can be unexpectedly improved through the cooperation of the components of the first film layer and the second film layer of the functional diaphragm and the gap setting characteristics.
Preferably, the second membrane layer is also allowed to be arranged between the negative electrode and the first membrane layer of the functional separator.
In the present invention, the materials of the positive electrode, the negative electrode, the electrolyte and the like may be any materials known in the lithium sulfur battery field, for example, the positive electrode is at least one of elemental sulfur, a porous composite material compounded with elemental sulfur, or polymer sulfur. The negative electrode is at least one of simple substance lithium and lithium alloy. The electrolyte comprises, for example, lithium sulfur battery organic solvents, lithium salts, and other auxiliary components, such as film forming additives, stability modifiers, and the like, are also allowed to be added.
The invention also provides a lithium sulfur battery, which comprises a battery shell, a battery core arranged in the battery shell and electrolyte infiltrating the battery core, wherein the battery core is the battery core of the invention.
The invention also provides a preparation method of the lithium-sulfur battery, which comprises the steps of superposing the layers according to the sequence of the anode, the first film layer, the second film layer and the anode to form a battery core, placing the battery core in a battery shell, injecting electrolyte and sealing;
or, the anode, the first film layer, the second film layer and the anode are soaked by electrolyte layer by layer, then stacked and placed in a battery shell for sealing, thus obtaining the battery.
Advantageous effects
According to the invention, PVDF-HFP is used as a matrix, and lithium salt and the additive are dispersed in the matrix, so that intramembrane cooperation can be realized, the membrane has good lithium ion conductivity at room temperature, the crystallinity of the polymer can be reduced, and meanwhile, an additional lithium ion migration channel can be provided, and the lithium ion migration number can be increased. The novel composite material is combined with the first film layer, and is further matched with the structural characteristics of clearance fit of the first film layer and the second film layer, so that cooperation can be generated, shuttle problems of polysulfide can be unexpectedly improved, and volume effect and structural stability can be relieved. According to research, through the synergistic combination of the substance and the structural functional membrane, various performances of the lithium-sulfur battery, such as capacity, multiplying power and cycling stability, can be effectively improved.
(2) The functional diaphragm is assembled according to the method of the invention, so that the shuttle effect of the polysulfide can be effectively blocked, the cycle performance of the lithium-sulfur battery is improved, and in addition, the clearance setting method of the diaphragm layer can further improve the infiltration of electrolyte and the mechanical performance of materials, thereby being beneficial to further synergistically improving the performance.
(3) The preparation method is simple, the cost is low, and the preparation method is easy for mass production and use.
Drawings
Figure 1 is an XRD pattern for the additive of example 1.
FIG. 2 is a graph of particle size analysis of the additive of example 1.
Fig. 3 is a schematic structural diagram of the lithium sulfur battery prepared in example 1.
Fig. 4 is a graph showing the cycle performance test of the lithium sulfur battery of example 1.
Detailed Description
In the following cases, unless specifically stated otherwise, the PVDF-HFP are 45.5 ten thousand molecular weight, CAS9011-17-0; the first film layers are Celgrad2400 films, and the thickness is 25 mu m.
Example 1:
the first step: preparation of Li 6.4 La 3 Ta 0.6 Zr 1.4 O 12 Additive:
mixing lithium source, zirconium dioxide, lanthanum oxide and tantalum oxide according to element metering ratio (Li 6.4 La 3 Ta 0.6 Zr 1.4 O 12 Setting the amount to be 0.02 mol), adding 30ml of isopropanol, ball milling the ball with 100g of ball milling weight, ball milling for 6 hours and rotating at 350r/min; taking outDrying the materials in an oven at 80 ℃ for 12 hours after the materials are discharged, taking out the dried materials, heating the materials in a muffle furnace, preserving heat for 8 hours at 950 ℃, putting the presintered materials into a ball mill again, adding isopropanol into the ball mill for wet milling to grind the materials, drying the materials at 80 ℃ for 12 hours at the rotating speed of 350r/min, and taking out the materials for vacuum preservation; as can be seen from XRD patterns, li 6.4 La 3 Ta 0.6 Zr 1.4 O 12 And is in a cubic crystal form. As can be seen from the particle size analysis, the D50 is 287nm;
and a second step of: process for preparing polymers
0.3g PVDF-HFP (45.5 g molecular weight, CAS 9011-17-0) was added to 3g NMP solvent, magnetically stirred for 1h to dissolve, followed by 0.13g lithium salt (LITFSI) and 0.03g Li of example 1 6.4 La 3 Ta 0.6 Zr 1.4 O 12 Stirring for 12h to obtain uniform mixed solution, and standing for 6h until bubbles disappear;
and a third step of: method for producing a polymer intermediate layer
Sucking the obtained mixed solution by a disposable dropper, uniformly dripping the mixed solution into a 17mm circular mold borne by a wood board, and vacuum drying at 60 ℃ for 6 hours to obtain a polymer intermediate layer (a second film layer with the thickness of 27.5 mu m, the porosity of 35% and the average pore diameter of 0.039 mu m);
to test the performance of the intermediate layer, a lithium sulfur battery was prepared.
The prepared polymer interlayer is used for assembling a lithium-sulfur battery, a sulfur/mesoporous carbon composite material is adopted as a positive electrode material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is adopted as an electrolyte by dissolving 1, 3-dioxolane and ethylene glycol dimethyl ether, and 1% LiNO is dissolved in the electrolyte 3 The electrolyte is dripped on both sides of the separator (Celgrad 2400, first film layer), and the assembly sequence of the battery is positive electrode/middle layer/separator/negative electrode, i.e. the middle layer is placed between the positive electrode and the separator of the battery (during the assembly process, the next layer is stacked after being wetted layer by layer with electrolyte according to the sequence). At room temperature of 25 ℃, the charge-discharge rate cycle test is carried out by using 0.5C. The initial capacity of the battery reaches 1301mAh/g, the battery capacity after 100 circles is 1013mAh/g, and the battery capacity after 200 circles is 953mAh/g.
Example 2:
the only difference compared with example 1 is that the additive is Li 6.6 La 3 Ta 0.4 Zr 1.6 O 12 The additive comprises the following steps:
the first step: preparation of Li 6.6 La 3 Ta 0.4 Zr 1.6 O 12 Additive:
the lithium source, zirconium dioxide, lanthanum oxide and tantalum oxide are dosed in the stoichiometric ratio (Li 6.6 La 3 Ta 0.4 Zr 1.6 O 12 Setting the amount to be 0.02 mol), adding 30ml of isopropanol, ball milling with the ball mass of 100g, ball milling for 6h and rotating at the speed of 350r/min; taking out, drying in an oven at 80 ℃ for 12 hours to remove the solvent, taking out the dried material, heating in a muffle furnace at 950 ℃ for 8 hours, placing the presintered material into ball milling again, adding isopropanol for wet milling, taking out the material for vacuum preservation after drying at 80 ℃ for 12 hours at the rotating speed of 350r/min;
and a second step of: preparation of the Polymer
Adding 0.3g PVDF-HFP (45.5 g molecular weight, CAS 9011-17-0) into 3g NMP solvent, magnetically stirring for 1h to dissolve, and sequentially adding 0.13g lithium salt (LITFSI) and 0.03g Li obtained in the first step 6.6 La 3 Ta 0.4 Zr 1.6 O 12 Stirring for 12h to obtain uniform mixed solution, and standing for 6h until bubbles disappear;
and a third step of: preparation of a Polymer interlayer
Sucking the obtained mixed solution by a disposable dropper, uniformly dripping the mixed solution into a 17mm circular mold borne by a wood board, and vacuum drying at 60 ℃ for 6 hours to obtain a polymer intermediate layer (a second film layer with the thickness of 27.5 mu m);
to test the performance of the intermediate layer, a lithium sulfur battery was prepared.
The prepared polymer interlayer is used for assembling a lithium-sulfur battery, a sulfur/mesoporous carbon composite material is adopted as a positive electrode material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is adopted as an electrolyte by dissolving 1, 3-dioxolane and ethylene glycol dimethyl ether, and 1% LiNO is dissolved in the electrolyte 3 The electrolyte is dripped on two sides of the diaphragm (the first film layer), and the assembly sequence of the battery is positive electrode/middle layer/diaphragm/negative electrodeI.e. the intermediate layer is placed between the positive electrode and the separator of the battery (during assembly, the next layer is stacked after being wetted layer by layer with electrolyte in the order described). At room temperature of 25 ℃, the initial capacity of the battery reaches 1253mAh/g by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 938mAh/g, and the battery capacity after 200 circles is 803mAh/g.
Example 3:
the only difference compared with example 1 is that the additive is Li 6 La 3 Zr 1.6 Al 0.2 Ta 0.4 O 12 The method comprises the following steps:
the first step: preparation of Li 6 La 3 Zr 1.6 Al 0.2 Ta 0.4 O 12 Additive:
mixing a lithium source, zirconium dioxide, lanthanum oxide, aluminum oxide and tantalum oxide according to stoichiometric ratio (Li 6.2 La 3 Zr 1.8 Al 0.2 Ta 0.2 O 12 Setting the amount to be 0.02 mol), adding 30ml of isopropanol, ball milling with the ball mass of 100g, ball milling for 6h and rotating at the speed of 350r/min; taking out, drying in an oven at 80 ℃ for 12 hours to remove the solvent, taking out the dried material, heating in a muffle furnace at 950 ℃ for 8 hours, placing the presintered material into ball milling again, adding isopropanol for wet milling, taking out the material for vacuum preservation after drying at 80 ℃ for 12 hours at the rotating speed of 350r/min;
and a second step of: preparation of the Polymer
Adding 0.3g PVDF-HFP (45.5 g molecular weight, CAS 9011-17-0) into 3g NMP solvent, magnetically stirring for 1h to dissolve, and sequentially adding 0.13g lithium salt (LITFSI) and 0.03. 0.03gLi 6 La 3 Zr 1.6 Al 0.2 Ta 0.4 O 12 Stirring for 12h to obtain uniform mixed solution, and standing for 6h until bubbles disappear;
and a third step of: preparation of a Polymer interlayer
Sucking the obtained mixed solution by a disposable dropper, uniformly dripping the mixed solution into a 17mm circular mold borne by a wood board, and vacuum drying at 60 ℃ for 6 hours to obtain a polymer intermediate layer (a second film layer with the thickness of 27.5 mu m);
to test the performance of the intermediate layer, a lithium sulfur battery was prepared.
The prepared polymer interlayer is used for assembling a lithium-sulfur battery, a sulfur/mesoporous carbon composite material is adopted as a positive electrode material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is adopted as an electrolyte by dissolving 1, 3-dioxolane and ethylene glycol dimethyl ether, and 1% LiNO is dissolved in the electrolyte 3 The electrolyte is dripped on two sides of the diaphragm, and the assembly sequence of the battery is positive electrode/middle layer/diaphragm/negative electrode, namely the middle layer is arranged between the positive electrode and the diaphragm of the battery (in the assembly process, the electrolyte is used for wetting layer by layer and then the next layer is overlapped. And under the condition of room temperature of 25 ℃, the initial capacity of the battery reaches 1335mAh/g by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 1138mAh/g, and the battery capacity after 200 circles is 1006mAh/g.
Examples: 4
The only difference compared to example 1 is the content of the components in the film, the third step of the difference being: PVDF-HFP is 0.3g, and the content of lithium salt is 50wt% based on the total weight of PVDF-HFP, lithium salt and additives; the content of the additive is 15wt%. Other steps and parameters were the same as in example 1.
Electrochemical performance data: the initial capacity of the battery reaches 1268mAh/g, the battery capacity after 100 circles is 982mAh/g, and the battery capacity after 200 circles is 887mAh/g.
Examples: 5
The only difference compared to example 1 is the content of the components in the film, the third step of the difference being: PVDF-HFP is 0.3g, and the content of lithium salt is 30wt% based on the total weight of PVDF-HFP, lithium salt and additives; the content of the additive was 5Wt%. Other steps and parameters were the same as in example 1.
Electrochemical performance data: the initial capacity of the battery reaches 1275mAh/g, the battery capacity after 100 circles is 1001mAh/g, and the battery capacity after 200 circles is 939mAh/g.
Example 6:
the difference compared to example 1 is only that in the third step, the second film layer obtained has a thickness of 20 μm.
Electrochemical performance data: the initial capacity of the battery reaches 1198mAh/g, the battery capacity after 100 circles is 977mAh/g, and the battery capacity after 200 circles is 845mAh/g.
Example 7:
the difference compared to example 1 is only that in the third step, the second film layer obtained has a thickness of 40 μm.
Electrochemical performance data: the initial capacity of the battery reaches 1216mAh/g, the battery capacity after 100 circles is 976mAh/g, and the battery capacity after 200 circles is 852mAh/g.
Comparative example 1:
the only difference compared to example 1 is that the second film layer is not stacked:
the positive electrode material adopts a sulfur/mesoporous carbon composite material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is dissolved in 1, 3-dioxolane and ethylene glycol dimethyl ether as electrolyte, and 1% LiNO is dissolved in the electrolyte 3 Electrolyte is dripped on two sides of the diaphragm, and the assembly sequence of the battery is positive electrode/diaphragm/negative electrode.
The initial capacity of the battery reaches 1064mAh/g under the condition of room temperature and 25 ℃ and the battery capacity decays to 632mAh/g after 100 circles by using a 0.5C charge-discharge rate cycle test.
Comparative example 2:
the only difference compared to example 1 is that no additives are added to the second film layer: the second step of distinction is:
adding 0.3g PVDF-HFP into 3g NMP solvent, magnetically stirring for 1h for dissolution, adding 0.13g lithium salt, stirring for 12h to obtain a uniform mixed solution, and standing for 6h until bubbles disappear; other steps and operation processes were the same as in example 1.
The electrochemical performance is as follows: the initial capacity of the battery reaches 1088mAh/g, the battery capacity is 826mAh/g after 100 circles, and the battery capacity is 624mAh/g after 200 circles.
Comparative example 3:
the difference compared to example 1 is only that the thickness of the second film layer is regulated to 53.8 μm. The third step of distinction is:
sucking the obtained mixed solution by a disposable dropper, uniformly dripping the mixed solution into a 17mm circular mold borne by a wood board, and vacuum drying at 60 ℃ for 6 hours to obtain a polymer intermediate layer (a second film layer with the thickness of 53.8 mu m); other steps and operation processes were the same as in example 1.
The initial capacity of the battery reaches 989mAh/g under the condition of room temperature 25 ℃ and by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 756mAh/g, and the battery capacity after 200 circles is 643mAh/g.
Comparative example 4:
the only difference compared to example 1 is that the PVDF is converted to replace PVDF-HFP as the polymer matrix of the second membrane layer, the second step of the difference being: and a second step of: preparation of the Polymer
Adding 0.3g of polyvinylidene fluoride (PVDF) into 3g of NMP solvent, magnetically stirring for 1h for dissolution, sequentially adding 0.13g of lithium salt and 0.03g of additive, stirring for 12h to obtain a uniform mixed solution, and standing for 6h until bubbles disappear; other steps and processes were the same as in example 1.
At room temperature of 25 ℃, the initial capacity of the battery reaches 975mAh/g by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 801mAh/g, and the battery capacity after 200 circles is 595mAh/g.
Comparative example 5:
the only difference compared to example 1 is that the first film layer is not used, the assembly process is:
the prepared polymer interlayer (second film layer) is used for assembling a lithium-sulfur battery, the anode material adopts a sulfur/mesoporous carbon composite material, a metal lithium sheet is used as a negative electrode, the assembling sequence of the battery is positive electrode/interlayer/negative electrode (in the assembling process, the next layer is stacked after being wetted by electrolyte layer by layer according to the sequence), namely, the interlayer is arranged between the positive electrode and the negative electrode of the battery. The initial capacity of the battery reaches 735mAh/g under the condition of room temperature 25 ℃ and by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 523mAh/g, and the battery capacity after 200 circles is 363mAh/g.
Comparative example 6:
the only difference compared to example 1 is that the first film layer and the second film layer are not stacked, but the second film layer is coated on the first film layer, and the third step is that:
uniformly coating the obtained mixed solution on the surface of a diaphragm by using a scalpel blade, and drying at 60 ℃ in vacuum for 6 hours to obtain a polymer intermediate layer which takes the diaphragm as a support, namely a diaphragm@intermediate layer;
the prepared diaphragm-supported polymer interlayer is used for assembling a lithium-sulfur battery, a sulfur/mesoporous carbon composite material is adopted as a positive electrode material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is dissolved in 1, 3-dioxolane and ethylene glycol dimethyl ether as electrolyte, and 1% LiNO is dissolved in the electrolyte 3 Electrolyte is dripped on two sides of the diaphragm@middle layer, the assembly sequence of the battery is positive electrode/diaphragm@middle layer/negative electrode (the coated middle layer faces the positive electrode, and in the assembly process, the next layer is stacked after being wetted by electrolyte layer by layer according to the sequence). At room temperature of 25 ℃, the initial capacity of the battery reaches 1057mAh/g by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 764mAh/g, and the battery capacity after 200 circles is 617mAh/g.
Comparative example 7:
the difference compared to example 1 is that the second layer is placed between the separator and the negative electrode, the difference steps are:
the prepared polymer interlayer is used for assembling a lithium-sulfur battery, a sulfur/mesoporous carbon composite material is adopted as a positive electrode material, a metal lithium sheet is used as a negative electrode, lithium bistrifluoromethylsulfonylimide is adopted as an electrolyte by dissolving 1, 3-dioxolane and ethylene glycol dimethyl ether, and 1% LiNO is dissolved in the electrolyte 3 The electrolyte is dripped on two sides of the separator, and the assembly sequence of the battery is positive electrode/separator/middle layer/negative electrode, namely the middle layer is arranged between the negative electrode of the battery and the separator. And under the condition of room temperature of 25 ℃, the initial capacity of the battery reaches 1019mAh/g by using a 0.5C charge-discharge rate cycle test, the battery capacity after 100 circles is 812mAh/g, and the battery capacity after 200 circles is 637mAh/g.
Comparative example 8
The only difference compared to example 1 is that the second film layer is replaced by a first film layer of equal thickness. Other operations and steps were the same as in example 1.
And under the condition of room temperature of 25 ℃, the initial capacity of the battery reaches 1132mAh/g by using a 0.5C charge-discharge rate cycle test, and the capacity of the battery after 100 circles is 751mAh/g.
Comparative example 9
The only difference compared to example 1 is that the first film layer is replaced by a second film layer of equal thickness. Other operations and steps were the same as in example 1.
The initial capacity of the battery reaches 956mAh/g and the battery capacity after 100 circles is 579mAh/g under the condition of room temperature and 25 ℃ and by using a 0.5C charge-discharge rate cycle test.
The above embodiments are merely for illustrating the design concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, the scope of the present invention is not limited to the above embodiments. Some modifications and variations of the present application shall fall within the scope of the present application.

Claims (19)

1. The lithium-sulfur battery functional diaphragm is characterized by comprising a first film layer and a second film layer, wherein a film gap exists between the first film layer and the second film layer;
the second film layer comprises a polymer matrix, and lithium salt and additives distributed in the matrix, wherein the additives are compounds with chemical expression of formula 1:
Li 7-x-3y La 3 Zr 2-x-z A y B x C z O 12 1 (1)
Wherein A is selected from at least one of Al and Ga, B is selected from at least one of Ta and Nb, and C is selected from at least one of Ge and Ti; x is more than 0 and less than or equal to 1, y is 0-0.4, and z is 0-1;
the polymer matrix material of the second membrane layer is PVDF-HFP.
2. The lithium sulfur battery functional separator of claim 1 wherein the first film layer is a polymeric film layer.
3. The lithium sulfur battery functional separator of claim 1 wherein the polymer of the first film layer is at least one of polypropylene, polyethylene oxide, polyvinylidene fluoride.
4. The lithium sulfur battery functional separator of claim 1 wherein the first film layer has a thickness of 20 to 40 μm; the porosity is 35-45%, and the average pore diameter is 0.028-0.043 μm.
5. The lithium sulfur battery functional separator of claim 1 wherein B comprises Ta, x is 0.4 to 0.6, and y, z = 0.
6. The lithium sulfur battery functional separator of claim 1 wherein a comprises Al and B comprises Ta; wherein x is 0.4-0.6, y is 0.2-0.4, and z is 0.
7. The lithium sulfur battery functional separator as in claim 1 wherein, of said additives,
the lithium salt is one or more of lithium bis (trifluoromethylsulfonyl) imide, lithium difluoromethyl imide and lithium tetrafluoroborate.
8. The lithium-sulfur battery functional separator according to claim 1, wherein the content of lithium salt in the second film layer is 30-50wt%; the content of the additive is 5-15 wt%.
9. The lithium sulfur battery functional separator of claim 1 wherein the second film layer has a thickness of 10 to 45 μm.
10. The lithium sulfur battery functional separator of claim 9, wherein the second film layer has a thickness of 20 to 40 μm.
11. The lithium sulfur battery functional separator of claim 1 wherein the second membrane layer has a porosity of 30% to 45% and an average pore size of 0.030 to 0.056 μm.
12. The lithium sulfur battery functional separator of claim 1 wherein the membrane gap is permeable to electrolyte.
13. The lithium sulfur battery functional separator of claim 1 wherein the first film layer and the second film layer are independent of each other.
14. The lithium sulfur battery functional separator of claim 1, wherein the lithium sulfur battery functional separator is formed by laminating a first film layer and a second film layer.
15. A method for preparing the lithium-sulfur battery functional separator according to any one of claims 1 to 14, characterized in that a first film layer and a second film layer are obtained; and then superposing the first film layer and the second film layer to obtain the adhesive.
16. The lithium-sulfur battery cell structure comprises a positive electrode, a negative electrode and a diaphragm for dividing the positive electrode and the negative electrode, and is characterized in that the diaphragm is the functional diaphragm according to any one of claims 1-14, wherein the second diaphragm layer is close to the positive electrode side.
17. The lithium sulfur battery cell structure of claim 16, wherein the second membrane layer is also allowed between the negative electrode and the first membrane layer of the functional separator.
18. A lithium-sulfur battery comprising a battery shell, a battery core arranged in the battery shell and electrolyte for infiltrating the battery core, wherein the battery core is the battery core as claimed in claim 16 or 17.
19. A method for preparing a lithium-sulfur battery according to claim 18, wherein the steps of stacking the layers in the order of the negative electrode, the first film layer, the second film layer and the positive electrode to form a battery cell, placing the battery cell in a battery shell, injecting electrolyte, and sealing;
or, the anode, the first film layer, the second film layer and the anode are soaked by electrolyte layer by layer, then stacked and placed in a battery shell for sealing, thus obtaining the battery.
CN202111254707.1A 2021-10-27 2021-10-27 Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery Active CN113871799B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111254707.1A CN113871799B (en) 2021-10-27 2021-10-27 Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111254707.1A CN113871799B (en) 2021-10-27 2021-10-27 Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery

Publications (2)

Publication Number Publication Date
CN113871799A CN113871799A (en) 2021-12-31
CN113871799B true CN113871799B (en) 2024-01-30

Family

ID=78997928

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111254707.1A Active CN113871799B (en) 2021-10-27 2021-10-27 Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur battery

Country Status (1)

Country Link
CN (1) CN113871799B (en)

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015050071A (en) * 2013-09-02 2015-03-16 日本碍子株式会社 Solid electrolyte ceramics material
KR20160057014A (en) * 2014-11-12 2016-05-23 한국기술교육대학교 산학협력단 High energy density lithium-sulfur battery having separator incorporated with active materials
JP2016115417A (en) * 2014-12-11 2016-06-23 株式会社リコー Positive electrode used for lithium sulfur secondary battery, and lithium sulfur secondary battery
WO2016184750A1 (en) * 2015-05-21 2016-11-24 Basf Se Glass-ceramic electrolytes for lithium-sulfur batteries
CN107369797A (en) * 2016-05-13 2017-11-21 中南大学 A kind of preparation method of lithium-sulfur cell barrier film
CN107579276A (en) * 2017-07-25 2018-01-12 华南理工大学 A kind of solid polymer electrolyte membrane and preparation method thereof and the application as lithium ion battery barrier film
KR101939142B1 (en) * 2017-07-28 2019-01-16 한국생산기술연구원 ALL SOLID LITHIUM SECONDARY BATTERY INCLUDING Ga-DOPED LLZO SOLID ELECTROLYTE AND MANUFACTURING METHOD FOR THE SAME
CN109742299A (en) * 2019-01-14 2019-05-10 上海大学(浙江·嘉兴)新兴产业研究院 A kind of diaphragm and preparation method thereof of multistage functional module coupling and complementing
CN109888372A (en) * 2019-02-25 2019-06-14 蜂巢能源科技有限公司 Electrolyte compound film for solid and its application
CN109888374A (en) * 2019-01-22 2019-06-14 华南理工大学 A kind of garnet-type solid electrolyte material and preparation method thereof adulterated more
CN113036073A (en) * 2019-12-09 2021-06-25 中国科学院上海硅酸盐研究所 Composite positive electrode for solid-state lithium-sulfur battery and preparation method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2016270820A1 (en) * 2015-06-01 2018-01-04 Pneumaticoat Technologies Llc Nano-engineered coatings for anode active materials, cathode active materials, and solid-state electrolytes and methods of making batteries containing nano-engineered coatings
CN111952551A (en) * 2019-05-17 2020-11-17 康宁股份有限公司 Improved composite positive electrode for solid-state lithium-sulfur battery and preparation method thereof
DE102020111624A1 (en) * 2020-04-29 2021-11-04 Schott Ag Aluminum-doped lithium ion conductor based on a garnet structure

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015050071A (en) * 2013-09-02 2015-03-16 日本碍子株式会社 Solid electrolyte ceramics material
KR20160057014A (en) * 2014-11-12 2016-05-23 한국기술교육대학교 산학협력단 High energy density lithium-sulfur battery having separator incorporated with active materials
JP2016115417A (en) * 2014-12-11 2016-06-23 株式会社リコー Positive electrode used for lithium sulfur secondary battery, and lithium sulfur secondary battery
WO2016184750A1 (en) * 2015-05-21 2016-11-24 Basf Se Glass-ceramic electrolytes for lithium-sulfur batteries
CN107369797A (en) * 2016-05-13 2017-11-21 中南大学 A kind of preparation method of lithium-sulfur cell barrier film
CN107579276A (en) * 2017-07-25 2018-01-12 华南理工大学 A kind of solid polymer electrolyte membrane and preparation method thereof and the application as lithium ion battery barrier film
KR101939142B1 (en) * 2017-07-28 2019-01-16 한국생산기술연구원 ALL SOLID LITHIUM SECONDARY BATTERY INCLUDING Ga-DOPED LLZO SOLID ELECTROLYTE AND MANUFACTURING METHOD FOR THE SAME
CN109742299A (en) * 2019-01-14 2019-05-10 上海大学(浙江·嘉兴)新兴产业研究院 A kind of diaphragm and preparation method thereof of multistage functional module coupling and complementing
CN109888374A (en) * 2019-01-22 2019-06-14 华南理工大学 A kind of garnet-type solid electrolyte material and preparation method thereof adulterated more
CN109888372A (en) * 2019-02-25 2019-06-14 蜂巢能源科技有限公司 Electrolyte compound film for solid and its application
CN113036073A (en) * 2019-12-09 2021-06-25 中国科学院上海硅酸盐研究所 Composite positive electrode for solid-state lithium-sulfur battery and preparation method thereof

Also Published As

Publication number Publication date
CN113871799A (en) 2021-12-31

Similar Documents

Publication Publication Date Title
US8953303B2 (en) Cathode active material for a lithium ion capacitor, and method for producing the cathode active material
US20220263121A1 (en) Al-doped sheet llzo composite solid-state electrolyte and preparation method and application thereof
US20120015256A1 (en) Sodium ion secondary battery
WO2020006788A1 (en) Method for preparing composite material of metal-organic frameworks and carbon nanotubes
KR20200030482A (en) Methods for preparing negative electrode for lithium secondary battery and lithium secondary battery
CN109704302B (en) Phosphorus-doped porous carbon material, preparation thereof and application thereof in coating diaphragm for lithium-sulfur battery
CN108933237B (en) Preparation method and application of lithium ion battery positive electrode material
CN109659528B (en) Potassium ion battery negative electrode active material, potassium ion battery negative electrode, potassium ion battery and application thereof
CN106207130A (en) A kind of lithium battery nickelic positive electrode of surface modification and preparation method thereof
CN107546357B (en) Lithium-sulfur battery, assembly thereof and application of functional material layer in lithium-sulfur battery
CN108258241A (en) A kind of cathode of lithium battery for inhibiting lithium dendrite growth using ZIF-8 porous carbon materials
CN109616698B (en) Lithium-sulfur battery electrolyte and preparation method thereof
KR102342216B1 (en) Anode layer and all solid state battery
CN114597532A (en) Method for directly regenerating failed lithium cobaltate positive electrode into high-voltage lithium cobaltate positive electrode and product
KR101295974B1 (en) Method for preparing lithium manganese oxide positive active material for lithium ion secondary battery, positive active material prepared thereby, and lithium ion secondary battery including the same
CN116216746A (en) Preparation method and application of Prussian blue material with high thermal stability
KR101646994B1 (en) Positive active material for rechargeable lithium battery, method for manufacturing the same, and rechargeable lithium battery including the same
CN109830656B (en) Preparation method of metal lithium cathode with solid-liquid composite interface layer
KR102343176B1 (en) Negative electrode active material for secondary battery, negative electrode including same and manufacturing method thereof
CN110571423A (en) Preparation method of nitrogen-carbon-coated nano titanium niobate electrode material
CN112952102B (en) Preparation method and application of composite metal oxide surface-modified lithium metal battery negative electrode current collector
JP2017033928A (en) Battery positive electrode material and lithium ion battery
CN105591107A (en) Ultrathin layered V5S8, preparing method of ultrathin layered V5S8 and application of ultrathin layered V5S8 to lithium-ion/sodium-ion battery
CN108767175A (en) A kind of preparation method of lithium-sulfur cell diaphragm
CN113871799B (en) Functional diaphragm, preparation method thereof and application of functional diaphragm in lithium-sulfur 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