CN116072877A - Battery and battery preparation method - Google Patents

Battery and battery preparation method Download PDF

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Publication number
CN116072877A
CN116072877A CN202310233212.3A CN202310233212A CN116072877A CN 116072877 A CN116072877 A CN 116072877A CN 202310233212 A CN202310233212 A CN 202310233212A CN 116072877 A CN116072877 A CN 116072877A
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positive electrode
battery
mixture
smear
tantalum disulfide
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Inventor
陈东旭
刘国锋
窦笠
吴晓梅
杨慧
王碧琼
高健
郭松峰
王旭
李丙涛
张仕琳
岳宇昂
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China Tower Co Ltd
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China Tower Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
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  • Manufacturing & Machinery (AREA)
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  • Condensed Matter Physics & Semiconductors (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a battery and a battery preparation method, and relates to the technical field of batteries, the battery comprises a battery core and electrolyte, the battery core comprises a positive pole piece, a negative pole piece and a diaphragm matrix arranged between the positive pole piece and the negative pole piece, the positive pole piece, the negative pole piece and the diaphragm matrix form a stacked structure or a winding structure, wherein the positive pole piece comprises: the positive electrode current collector is used for transmitting electrons; the positive electrode smear is coated on the surface of the positive electrode current collector and comprises nano sulfur and tantalum disulfide. According to the invention, the volume energy density of the battery is improved by adding nano sulfur and tantalum disulfide into the positive electrode smear.

Description

Battery and battery preparation method
Technical Field
The invention relates to the technical field of batteries, in particular to a battery and a battery preparation method.
Background
Lithium batteries have high energy density characteristics and are widely used in the field of electronic devices or automobiles. In the related art, the energy density of a battery is increased by adding conductive carbon to a positive electrode tab of the battery and rolling the positive electrode tab. But the positive plate hole after rolling is reduced, the contact of the electrolyte and the sulfur ions of the positive plate is reduced, the sulfur ions cannot fully react, the transmission of lithium ions and electrons is blocked, and the volume energy density of the battery is low.
As can be seen, the related art has a problem in that the volumetric energy density of the battery is low.
Disclosure of Invention
The embodiment of the invention provides a battery and a battery preparation method, which are used for solving the problem of low volume energy density of the battery in the related technology.
To solve the above problems, the present invention is achieved as follows:
in a first aspect, an embodiment of the present invention provides a battery, including an electrical core and an electrolyte, where the electrical core includes a positive electrode sheet, a negative electrode sheet, and a separator matrix between the positive electrode sheet and the negative electrode sheet, where the positive electrode sheet, the negative electrode sheet, and the separator matrix form a stacked structure or a wound structure,
the positive electrode sheet includes:
the positive electrode current collector is used for transmitting electrons;
the positive electrode smear is coated on the surface of the positive electrode current collector and comprises nano sulfur and tantalum disulfide.
Alternatively, the positive electrode smear is a rolled smear, and the thickness of the positive electrode smear before rolling is 50 μm to 300 μm.
Optionally, the load of the positive electrode current collector before rolling the positive electrode smear is 2mg/cm 2 To 6mg/cm 2 。
Optionally, the positive electrode smear further comprises a conductive additive, an adhesive, and a solvent, wherein,
the conductive additive comprises one of acetylene black, ketjen black and carbon nanotubes;
the adhesive comprises one of polyvinylidene fluoride, polyethylene oxide, polyacrylic acid and polyvinyl alcohol;
the solvent comprises dimethylformamide or N-methylpyrrolidone.
Optionally, the ratio of the mass of the mixed nano sulfur and the mass of the tantalum disulfide to the mass of the conductive additive and the mass of the adhesive is 8:1:1.
Alternatively, the nano sulfur is obtained by the following method:
ball milling sodium thiosulfate and the multilayer graphene sheets;
soaking the ball-milled mixture in hydrochloric acid with the concentration of 1-30wt%;
wherein the mass ratio of the sodium thiosulfate to the multilayer graphene sheet is 10:1 to 250:1.
Optionally, the tantalum disulfide is flaky tantalum disulfide powder, and the flaky tantalum disulfide powder is obtained by the following steps:
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying;
wherein the concentration of the tantalum disulfide in the absolute ethyl alcohol is 0.2g/mL to 40g/mL.
Optionally, the electrolyte comprises 1,3 dioxolane, ethylene glycol dimethyl ether, lithium bistrifluoromethane sulfonyl imide and lithium nitrate, wherein,
the mass ratio of the 1,3 dioxolane to the ethylene glycol dimethyl ether is 1:1;
the content of the lithium bistrifluoro-methylsulfonyl imide is 1mol/L;
the content of the lithium nitrate is 0.2wt%.
Optionally, the membrane substrate is a polyethylene membrane or a polypropylene membrane.
In a second aspect, an embodiment of the present invention further provides a method for preparing a battery, including:
ball milling sodium thiosulfate and the multilayer graphene sheets to obtain a first mixture;
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying to obtain flaky tantalum disulfide powder;
soaking the first mixture in hydrochloric acid to obtain a second mixture, wherein the second mixture comprises nano sulfur;
mixing the second mixture with the flaky tantalum disulfide powder, and cleaning the mixture by distilled water to obtain a third mixture, wherein the third mixture comprises the flaky tantalum disulfide powder and the nano sulfur;
uniformly mixing the third mixture with a conductive additive and a binder, adding a solvent, and ball-milling and stirring in a vacuum environment to obtain an anode smear;
coating the positive electrode smear on a positive electrode current collector, and heating and drying under vacuum to obtain an initial positive electrode plate;
rolling the initial positive electrode plate to obtain a target positive electrode plate;
stacking or convoluting the target positive pole piece, the target negative pole piece and the diaphragm matrix to obtain an electric core;
and preparing the battery according to the battery core and the electrolyte.
In the embodiment of the invention, the positive electrode smear comprising nano sulfur and tantalum disulfide is coated on the surface of the positive electrode current collector, wherein the nano sulfur has larger specific surface area, so that the surface area of the sulfur in contact with electrolyte can be increased, sulfide ions can fully react, and the obstruction of electron transmission is reduced; meanwhile, tantalum disulfide has higher lithium ion conductivity, can effectively improve the transmission rate of lithium ions, improve the transmission rate of lithium ions and electrons, slow down the capacity fading rate of a battery and improve the volume energy density of the battery.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.
Fig. 1 is a schematic structural view of a battery according to an embodiment of the present invention;
fig. 2 is a flowchart of a battery preparation method provided in an embodiment of the present invention;
FIG. 3 is a graph of charge and discharge for different turns provided by an embodiment of the present invention;
fig. 4 is a first-turn charge-discharge graph provided by an embodiment of the present invention;
fig. 5 is a graph of 100 cycles provided by an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a battery according to an embodiment of the present invention, as shown in fig. 1, the battery includes a battery cell 10 and an electrolyte 20, the battery cell 10 includes a positive electrode sheet 101, a negative electrode sheet 102, and a separator substrate 103 located between the positive electrode sheet 101 and the negative electrode sheet 102, the positive electrode sheet 101, the negative electrode sheet 102 and the separator substrate 103 form a stacked structure or a wound structure, wherein,
the positive electrode sheet 101 includes:
a positive current collector 1011, the positive current collector 1011 for transporting electrons;
a positive electrode smear 1012, wherein the positive electrode smear 1012 is coated on the surface of the positive electrode current collector 1011, and the positive electrode smear 1012 comprises nano sulfur and tantalum disulfide.
The nano sulfur is in-situ generated nano sulfur, and the particle size of the nano sulfur is smaller, so that the nano sulfur has larger specific surface area, the conductive additive and tantalum disulfide are more tightly adhered in the positive electrode smear 1012, the surface area of the sulfur contacted with the electrolyte 20 is increased in the battery circulation process, sulfide ions can fully react, and the obstruction of electron transmission is reduced.
The tantalum disulfide has a layered structure and high ionic conductivity, so that the lithium ion conductivity of the battery positive electrode plate 101 can be effectively improved, and the rapid capacity degradation caused by poor wettability of the electrolyte 20 due to volume reduction can be alleviated.
Further, tantalum disulfide has a tantalum-sulfur bond, which can specifically accelerate the conversion of polysulfide in a lithium-sulfur battery, catalyze electrochemical reactions, promote reaction kinetics, and further improve the cycle performance of the battery.
In the embodiment of the invention, the positive electrode smear 1012 comprising nano sulfur and tantalum disulfide is coated on the surface of the positive electrode current collector 1011, wherein the nano sulfur has larger specific surface area, so that the surface area of the sulfur in contact with the electrolyte 20 can be increased, sulfide ions can fully react, and the obstruction of electron transmission is reduced; meanwhile, tantalum disulfide has higher lithium ion conductivity, can effectively improve the lithium ion conduction rate, and slows down the capacity fading rate of the battery, so that the volume energy density of the battery is improved.
In one embodiment, the positive electrode smear 1012 is a rolled smear, and the positive electrode smear 1012 has a thickness of 50 μm to 300 μm before rolling.
It will be appreciated that rolling the positive electrode smear 1012 reduces the thickness of the positive electrode smear 1012, thereby reducing the thickness of the positive electrode sheet 101, resulting in an increase in volumetric energy density of the battery. However, in the related art, after the positive electrode smear 1012 is rolled, the hole measured on the positive electrode after rolling will be significantly collapsed, and due to the insulating property of sulfur and poor lithium ion transmission capability, the infiltration capability of the electrolyte 20 will be significantly reduced due to the lack of the positive electrode sheet with holes under high compaction density, the transmission of electrons and lithium ions will be blocked, the sulfur ions will not perform sufficient oxidation-reduction reaction, and the polarization phenomenon of the battery will be more obvious, thereby causing a rapid decrease in unit capacity and cycle performance.
In this embodiment, the positive electrode smear 1012 includes tantalum disulfide, and the tantalum disulfide has better ductility, and can be used as an interlayer lubricant in the compaction process to reduce the cracking of the electrode sheet, so that the porosity of the positive electrode smear 1012 is kept at a higher level, the electrolyte 20 and the positive electrode sheet 101 can be fully infiltrated, so that the sulfide ions can fully react with electrons, and the unit capacity and the cycle performance of the battery are improved.
Preferably, the positive electrode smear 1012 has a thickness after rolling of 40% to 80% of the thickness before rolling.
In one embodiment, the positive electrode current collector 1011 has a load of 2mg/cm before the positive electrode smear 1012 is rolled 2 To 6mg/cm 2 。
It should be appreciated that the positive electrode smear 1012 had a load of 2mg/cm before rolling 2 To 6mg/cm 2 The thickness of the positive electrode smear 1012 after rolling becomes 40% -80% before rolling, so that the load of the positive electrode smear 1012 after rolling is more than 6mg/cm 2 To improve the battery in a high load stateIs a high energy density.
Further, the inclusion of tantalum disulfide in the positive electrode smear 1012 reduces polarization of the positive electrode smear 1012 under high load conditions, thereby improving the stability of the battery.
In one embodiment, the positive electrode smear 1012 further comprises conductive additives, adhesives, and solvents, wherein,
the conductive additive comprises one of acetylene black, ketjen black and carbon nanotubes;
the adhesive comprises one of polyvinylidene fluoride, polyethylene oxide, polyacrylic acid and polyvinyl alcohol;
the solvent comprises dimethylformamide or N-methylpyrrolidone.
The above-described conductive additives are used to increase the ability of the positive electrode smear 1012 to transport electrons, thereby increasing the conductivity of the positive electrode smear 1012. The conductive additive can be one of acetylene black, ketjen black and carbon nano tubes, or a mixture of a plurality of acetylene black, ketjen black and carbon nano tubes. Acetylene black, ketjen black and carbon nanotubes have good conductivity, and the conductive additive comprises one of acetylene black, ketjen black and carbon nanotubes, so that the conductivity of the positive electrode smear 1012 can be effectively improved.
The adhesive is used for adhering and fixing nano sulfur, tantalum disulfide and a conductive additive on the surface of the positive current collector 1011, so as to prepare the positive electrode plate 101. The adhesive comprises one of polyvinylidene fluoride, polyethylene oxide, polyacrylic acid and polyvinyl alcohol, can be tightly combined with tantalum disulfide, nano sulfur and a conductive additive, and can be fixed on the surface of the positive current collector 1011 after being dried by coating on the positive current collector 1011.
The solvent is used for dissolving tantalum disulfide, nano sulfur, a conductive additive and an adhesive, so that the tantalum disulfide, the nano sulfur, the conductive additive and the adhesive can be fully dispersed and mixed in the solvent, ball milling and stirring are carried out in a vacuum environment, a uniform mixture of the positive electrode smear 1012 is obtained, and the mixture is coated on the surface of the positive electrode current collector 1011 and dried to obtain the positive electrode sheet 101. Wherein the solvent comprises dimethylformamide or N-methylpyrrolidone, and tantalum disulfide, nano sulfur, a conductive additive and an adhesive are effectively dispersed through ultrasonic energy; and simultaneously can volatilize in the drying process after coating to remove redundant dimethylformamide or N-methylpyrrolidone.
In an embodiment of the present invention, the positive electrode smear 1012 includes a conductive additive, an adhesive, and a solvent, the conductive additive enhancing the conductive performance of the positive electrode smear 1012; the adhesive is used for adhering and fixing nano sulfur, tantalum disulfide and a conductive additive on the surface of the positive current collector 1011 so as to prepare a positive electrode plate 101; the solvent is used for dissolving tantalum disulfide, nano sulfur, a conductive additive and an adhesive, so that the tantalum disulfide, the nano sulfur, the conductive additive and the adhesive can be fully dispersed and mixed in the solvent, ball milling and stirring are carried out in a vacuum environment, a uniform mixture of the positive electrode smear 1012 is obtained, and the mixture is coated on the surface of the positive electrode current collector 1011 and dried, so that the positive electrode sheet 101 is obtained. By adding conductive additives, adhesives, and solvents to the positive electrode smear 1012, the electrical cycle performance of the positive electrode sheet 101 is improved.
In one embodiment, the ratio of the mass of the mixed nano sulfur and tantalum disulfide to the mass of the conductive additive and the mass of the binder is 8:1:1.
It should be appreciated that the main components of the positive electrode smear 1012 are nano sulfur and tantalum disulfide for improving the electrical cycle performance of the positive electrode sheet 101. The conductive additive is used for increasing the electron transmission capability of the positive electrode smear 1012, the adhesive is used for bonding tantalum disulfide, nano sulfur and the conductive additive, the conductive additive plays an auxiliary role in the positive electrode smear 1012, the electric circulation performance of the positive electrode sheet 101 is poor easily caused by the higher content in the positive electrode smear 1012, and the positive electrode smear 1012 is separated from the positive electrode current collector 1011 easily caused by the lower content in the positive electrode smear 1012, so that the damage of the battery is caused. Therefore, in the embodiment, the ratio of the mass of the mixed nano sulfur and tantalum disulfide to the mass of the conductive additive to the mass of the adhesive is 8:1:1, so that the prepared positive electrode smear 1012 can be tightly fixed on the surface of the positive electrode current collector 1011, and has better electrical circulation performance.
In one embodiment, the nanosulfur is obtained by:
ball milling sodium thiosulfate and the multilayer graphene sheets;
soaking the ball-milled mixture in hydrochloric acid with the concentration of 1-30wt%;
wherein the mass ratio of the sodium thiosulfate to the multilayer graphene sheet is 10:1 to 250:1.
The nano sulfur is generated in situ and is obtained by reacting sodium thiosulfate with dilute hydrochloric acid. Specifically, ball-milling a plurality of layers of graphene sheets of sodium thiosulfate, soaking the ball-milled mixture in hydrochloric acid with the concentration of 1-30wt%, and reacting for a period of time to generate nano sulfur particles in situ.
The mass ratio of the sodium thiosulfate to the multilayer graphene sheets is 10:1-250:1, and the ball milling time is 30-60 minutes, so that the sodium thiosulfate can be fully ball-milled, and can be uniformly reacted with dilute hydrochloric acid in the reaction process to generate nano sulfur in situ.
In one embodiment, the tantalum disulfide is a flaky tantalum disulfide powder obtained by:
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying;
wherein the concentration of the tantalum disulfide in the absolute ethyl alcohol is 0.2g/mL to 40g/mL.
The tantalum disulfide is obtained by ultrasonic dispersion in absolute ethyl alcohol and drying, wherein the concentration of the tantalum disulfide in the absolute ethyl alcohol is 0.2g/mL to 40g/mL, and the drying temperature after ultrasonic treatment is 50 ℃ to 70 ℃ so that the tantalum disulfide is in a flaky shape.
Further, after the flaky tantalum disulfide is obtained, adding the flaky tantalum disulfide into the dried nano sulfur mixture, adding hydrochloric acid, mixing and stirring, then washing with distilled water for a plurality of times, removing hydrochloric acid and unreacted sodium thiosulfate, and then heating and drying in a vacuum environment to finally obtain the mixture of tantalum disulfide and nano sulfur.
In the embodiment of the invention, the tantalum disulfide is added into the absolute ethyl alcohol, and then is subjected to ultrasonic dispersion and drying to obtain the flaky tantalum disulfide, and the flaky structure is beneficial to the transmission of lithium ions, so that the electric cycle performance of the battery is improved.
In one embodiment, the electrolyte 20 includes 1,3 dioxolane, ethylene glycol dimethyl ether, lithium bistrifluoro methanesulfonimide, and lithium nitrate, wherein,
the mass ratio of the 1,3 dioxolane to the ethylene glycol dimethyl ether is 1:1;
the content of the lithium bistrifluoro-methylsulfonyl imide is 1mol/L;
the content of the lithium nitrate is 0.2wt%.
The electrolyte 20 is used for transporting lithium ions to complete an electric cycle, so that the electrolyte 20 has a large amount of lithium ions. In the embodiment, lithium ions are provided by the lithium bistrifluoro methanesulfonimide and the lithium nitrate, and meanwhile, the 1,3 dioxolane and the ethylene glycol dimethyl ether are used as solvents to efficiently transmit the lithium ions, so that the battery has higher electric cycle performance.
The mass ratio of the 1,3 dioxolane to the ethylene glycol dimethyl ether is 1:1, the content of the lithium bistrifluoromethane sulfonyl imide is 1mol/L, and the content of the lithium nitrate is 0.2wt%, so that the electrolyte 20 can rapidly conduct lithium ions while containing more lithium ions, and the battery can maintain a higher electric cycle performance level.
In one embodiment, the membrane substrate 103 is a polyethylene membrane or a polypropylene membrane.
The separator substrate 103 is located between the positive electrode plate 101 and the negative electrode plate 102, and lithium ions need to pass through the separator substrate 103 to perform electric circulation during the battery cycle, so the separator substrate 103 needs to have better capability of passing through lithium ions. The separator substrate 103 is a polyethylene separator or a polypropylene separator, so that lithium ions can efficiently pass through the separator substrate 103 during the battery cycle, and the battery can maintain a high level of electrical cycle performance.
Referring to fig. 2, fig. 2 is a flowchart of a method for preparing a battery according to the present invention, as shown in fig. 2, the method includes:
ball milling sodium thiosulfate and the multilayer graphene sheets to obtain a first mixture;
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying to obtain flaky tantalum disulfide powder;
soaking the first mixture in hydrochloric acid to obtain a second mixture, wherein the second mixture comprises nano sulfur;
mixing the second mixture with the flaky tantalum disulfide powder, and cleaning the mixture by distilled water to obtain a third mixture, wherein the third mixture comprises the flaky tantalum disulfide powder and the nano sulfur;
uniformly mixing the third mixture with a conductive additive and a binder, adding a solvent, and ball-milling and stirring in a vacuum environment to obtain an anode smear;
coating the positive electrode smear on a positive electrode current collector, and heating and drying under vacuum to obtain an initial positive electrode plate;
rolling the initial positive electrode plate to obtain a target positive electrode plate;
stacking or convoluting the target positive pole piece, the target negative pole piece and the diaphragm matrix to obtain an electric core;
and preparing the battery according to the battery core and the electrolyte.
Various examples can be prepared for comparison by the above method to show improvements in the cycle performance of the battery. The method comprises the following specific steps:
the battery of example 1 was prepared:
mixing 2g of sodium thiosulfate and 40mg of the multilayer graphene sheets, and ball-milling for 30 minutes to ensure uniform mixing of the two materials, wherein the ball-milled materials are called a mixture A;
dispersing 500mg tantalum disulfide in 1000ml alcohol by ultrasonic for 1 hour to obtain uniform tantalum disulfide powder in a flake form, and then drying in vacuum at 60 ℃;
completely soaking the mixture A in 50ml of dilute hydrochloric acid (the concentration of hydrochloric acid is 15 wt%) to make the mixture A fully react for 6 hours, and utilizing the reaction of sodium thiosulfate and hydrochloric acid to make in-situ generation of nano sulfur particles so as to obtain a mixture B;
the dried tantalum disulfide powder was added while adding 5ml of diluted hydrochloric acid (hydrochloric acid concentration 5 wt%) again, and mixed for 6 hours with stirring to thoroughly mix tantalum disulfide with the mixture B, followed by washing with distilled water several times to completely remove hydrochloric acid and unreacted sodium thiosulfate. Then drying for 6 hours at 80 ℃ in a vacuum environment to finally obtain a mixture C;
16mg of mixture C, 2mg of acetylene black and 2mg of polyvinylidene fluoride were uniformly mixed, and 1ml of N-methylpyrrolidone was added. Ball milling and stirring for 3 hours in a vacuum environment to obtain uniform and viscous slurry;
uniformly coating the slurry on the surface of an aluminum current collector, wherein the coating thickness is 200 mu m, and the load is 3mg/cm 2 Vacuum drying at 80 ℃ for 8 hours to obtain a preliminary positive electrode plate;
and rolling the preliminary positive pole piece to finally obtain a rolled pole piece with the thickness of 80% of the original thickness, and naming the rolled pole piece as a tantalum disulfide/sulfur positive pole piece.
The lithium-sulfur battery corresponding to example 1 was assembled in a glove box using tantalum disulfide/sulfur positive electrode sheets, the negative electrode was a lithium sheet, the separator matrix was a polyethylene separator, and the electrolyte was 1,3 dioxolane: ethylene glycol dimethyl ether, 1mol/L lithium bistrifluoro methanesulfonimide, 0.2wt% lithium nitrate.
The battery of example 2 was prepared:
mixing 4g of sodium thiosulfate and 60mg of a conductive additive, and ball milling for 60 minutes to ensure uniform mixing of the two materials, wherein the ball-milled materials are called a mixture A;
ultrasonic dispersing 250mg tantalum disulfide in 200ml alcohol for 1 hour to obtain uniform tantalum disulfide powder in a flake form, followed by vacuum drying at 60 ℃;
completely soaking the mixture A in 75ml of dilute hydrochloric acid (the concentration of hydrochloric acid is 30 wt%) to make the mixture A fully react for 12 hours, and utilizing the reaction of sodium thiosulfate and hydrochloric acid to make in-situ generation of nano sulfur particles so as to obtain a mixture B;
the dried tantalum disulfide powder was added while adding 7ml of diluted hydrochloric acid (hydrochloric acid concentration 10 wt%) again, and mixed for 6 hours with stirring to thoroughly mix tantalum disulfide with the mixture B, followed by washing with distilled water several times to completely remove hydrochloric acid and unreacted sodium thiosulfate. Then drying for 6 hours at 80 ℃ in a vacuum environment to finally obtain a mixture C;
40mg of mixture C, 4mg of ketjen black and 4mg of polyacrylic acid were uniformly mixed, and 2ml of dimethylformamide was added. Ball milling and stirring for 3 hours in a vacuum environment to obtain uniform and viscous slurry;
uniformly coating the slurry on the surface of an aluminum current collector, wherein the coating thickness is 400 mu m, and the load is 6mg/cm 2 Vacuum drying at 80deg.C for 12 hr;
and rolling the pole piece to finally obtain the rolled pole piece with the thickness of 60% of the original thickness, and the rolled pole piece is named as tantalum disulfide/sulfur positive pole piece.
The lithium-sulfur battery corresponding to example 2 was assembled in a glove box using tantalum disulfide/sulfur positive electrode sheet, the negative electrode was a lithium sheet, the separator matrix was a polyethylene separator, and the electrolyte was 1,3 dioxolane: ethylene glycol dimethyl ether, 1mol/L lithium bistrifluoro methanesulfonimide, 0.2wt% lithium nitrate.
The battery of comparative example 1 was prepared:
mixing 20mg of elemental sulfur, acetylene black and polyvinylidene fluoride according to a mass ratio of 8:1:1, adding 300 mu l of N-methylpyrrolidone, grinding for 30min at a temperature of 20 ℃, uniformly coating the mixture on an aluminum foil, and drying the mixture in a vacuum drying box at a temperature of 60 ℃ for 24h. And rolling the pole piece to finally obtain the rolled pole piece with the thickness of 80% of the original thickness, and the rolled pole piece is named as a carbon/sulfur positive pole piece. The lithium sulfur battery corresponding to comparative example 1 was assembled and tested in the same manner as in example 1.
A battery of comparative example 2 was prepared:
mixing 20mg of elemental sulfur, acetylene black and polyvinylidene fluoride according to a mass ratio of 8:1:1, adding 300 mu l of N-methylpyrrolidone, grinding for 30min at a temperature of 20 ℃, uniformly coating the mixture on an aluminum foil, and drying the mixture in a vacuum drying box at a temperature of 60 ℃ for 24h. And rolling the pole piece to finally obtain the rolled pole piece with the thickness of 60% of the original thickness, and the rolled pole piece is named as a carbon/sulfur positive pole piece. The lithium sulfur battery corresponding to comparative example 2 was assembled and tested in the same manner as in example 1.
The batteries corresponding to example 1, example 2, comparative example 1 and comparative example 2 were charged and dischargedElectrical testing resulted in the test results shown in fig. 3, 4 and 5. Among them, fig. 3 is a charge-discharge graph of example 1 and comparative example 1 at different turns. Specifically, FIG. 3 shows the current density of the lithium sulfur battery obtained in example 1 and comparative example 1 of the present invention at 2mAcm -2 Charge and discharge curves after 1 and 100 cycles, respectively. As can be seen from the graph, compared with the carbon/sulfur anode prepared by the traditional method, the first circle of capacity of the tantalum disulfide/sulfur anode can reach 1300mAh/g after being compressed, and the tantalum disulfide/sulfur anode still has a considerable capacity of 1100mAh/g after 100 times of circulation, and has obvious improvement compared with the common carbon/sulfur anode (100 circles only remain less than 600 mAh/g). This is mainly due to the rapid ion conductivity of tantalum disulfide, which still ensures lithium ion transport even in the absence of voids, avoiding loss of overall capacity.
Among them, fig. 4 is a graph of the first charge and discharge of example 2 and comparative example 2 of the present invention before and after rolling. As can be seen from the figure, the lithium sulfur battery prepared in example 2 effectively avoids the decrease of the battery capacity before and after rolling, and ensures the stability of the overall capacity; in contrast, in the lithium sulfur battery obtained in comparative example 2, the electrolyte is difficult to infiltrate due to the rapid decrease in porosity of the rolled electrode sheet, and the unit capacity of the battery shows a significant decrease trend after rolling, which also results in rapid degradation of the battery cycle. From experimental data, it can be found that tantalum disulfide/sulfur positive electrodes are better able to resist capacity fade caused by volume compression.
Wherein, fig. 5 is a cycle curve of the lithium sulfur battery obtained in example 2 after 100 times, for the tantalum disulfide/sulfur positive electrode sheet, a considerable unit capacity of 1370mAh/g (the carbon/sulfur positive electrode sheet is only 990 mAh/g) can still be obtained after compacting, and in particular, after 100 times of cycle, the tantalum disulfide/sulfur positive electrode sheet still maintains a unit capacity of 920mAh/g, which is far higher than 360mAh/g of the carbon/sulfur positive electrode sheet. This is mainly due to the better contact area of the in-situ generated nano sulfur with the conductive additive and the rapid lithium ion transport capability of tantalum disulfide.
In summary, the battery made of the tantalum disulfide/sulfur positive plate obtained by the embodiment of the invention has better lithium ion transmission capacity, thereby improving the electrical cycle performance of the battery.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.

Claims (10)

1. A battery is characterized by comprising an electric core and electrolyte, wherein the electric core comprises a positive pole piece, a negative pole piece and a diaphragm matrix positioned between the positive pole piece and the negative pole piece, the positive electrode plate, the negative electrode plate and the diaphragm matrix form a stacked structure or a winding structure, wherein,
the positive electrode sheet includes:
the positive electrode current collector is used for transmitting electrons;
the positive electrode smear is coated on the surface of the positive electrode current collector and comprises nano sulfur and tantalum disulfide.
2. The battery according to claim 1, wherein the positive electrode smear is a rolled smear having a thickness of 50 μm to 300 μm before rolling.
3. The battery of claim 2, wherein the positive electrode current collector has a load of 2mg/cm before the positive electrode smear roll-in 2 To 6mg/cm 2 。
4. The battery according to any one of claims 1 to 3, wherein the positive electrode smear further comprises a conductive additive, a binder and a solvent, wherein,
the conductive additive comprises one of acetylene black, ketjen black and carbon nanotubes;
the adhesive comprises one of polyvinylidene fluoride, polyethylene oxide, polyacrylic acid and polyvinyl alcohol;
the solvent comprises dimethylformamide or N-methylpyrrolidone.
5. The battery of claim 4, wherein the ratio of the mass of the mixed nano sulfur and tantalum disulfide to the mass of the conductive additive and the mass of the binder is 8:1:1.
6. A battery according to any one of claims 1 to 3, characterized in that the nanosulfur is obtained by:
ball milling sodium thiosulfate and the multilayer graphene sheets;
soaking the ball-milled mixture in hydrochloric acid with the concentration of 1-30wt%;
wherein the mass ratio of the sodium thiosulfate to the multilayer graphene sheet is 10:1 to 250:1.
7. A battery according to any one of claims 1 to 3, wherein the tantalum disulfide is a flaky tantalum disulfide powder obtained by:
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying;
wherein the concentration of the tantalum disulfide in the absolute ethyl alcohol is 0.2g/mL to 40g/mL.
8. The battery according to any one of claims 1 to 3, wherein the electrolyte comprises 1,3 dioxolane, ethylene glycol dimethyl ether, lithium bistrifluoromethane sulfonyl imide and lithium nitrate, wherein,
the mass ratio of the 1,3 dioxolane to the ethylene glycol dimethyl ether is 1:1;
the content of the lithium bistrifluoro-methylsulfonyl imide is 1mol/L;
the content of the lithium nitrate is 0.2wt%.
9. A battery according to any one of claims 1 to 3, wherein the separator substrate is a polyethylene separator or a polypropylene separator.
10. A method of making a battery comprising:
ball milling sodium thiosulfate and the multilayer graphene sheets to obtain a first mixture;
adding tantalum disulfide into absolute ethyl alcohol, performing ultrasonic dispersion, and drying to obtain flaky tantalum disulfide powder;
soaking the first mixture in hydrochloric acid to obtain a second mixture, wherein the second mixture comprises nano sulfur;
mixing the second mixture with the flaky tantalum disulfide powder, and cleaning the mixture by distilled water to obtain a third mixture, wherein the third mixture comprises the flaky tantalum disulfide powder and the nano sulfur;
uniformly mixing the third mixture with a conductive additive and a binder, adding a solvent, and ball-milling and stirring in a vacuum environment to obtain an anode smear;
coating the positive electrode smear on a positive electrode current collector, and heating and drying under vacuum to obtain an initial positive electrode plate;
rolling the initial positive electrode plate to obtain a target positive electrode plate;
stacking or convoluting the target positive pole piece, the target negative pole piece and the diaphragm matrix to obtain an electric core;
and preparing the battery according to the battery core and the electrolyte.
CN202310233212.3A 2023-03-13 2023-03-13 Battery and battery preparation method Pending CN116072877A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103650215A (en) * 2011-07-11 2014-03-19 巴斯夫欧洲公司 Electrode material comprising metal sulfide
CN105826556A (en) * 2016-03-27 2016-08-03 华南理工大学 Ultrathin-layered NbS2, preparing method thereof and application of ultrathin-layered NbS2 to lithium/sodium-ion battery
CN107785554A (en) * 2017-10-26 2018-03-09 陕西聚洁瀚化工有限公司 The preparation method of lithium-sulfur cell graphene nano sulphur composite positive pole
CN112038589A (en) * 2019-06-04 2020-12-04 中国科学院物理研究所 High energy density aluminum secondary battery, positive electrode material thereof and preparation method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103650215A (en) * 2011-07-11 2014-03-19 巴斯夫欧洲公司 Electrode material comprising metal sulfide
CN105826556A (en) * 2016-03-27 2016-08-03 华南理工大学 Ultrathin-layered NbS2, preparing method thereof and application of ultrathin-layered NbS2 to lithium/sodium-ion battery
CN107785554A (en) * 2017-10-26 2018-03-09 陕西聚洁瀚化工有限公司 The preparation method of lithium-sulfur cell graphene nano sulphur composite positive pole
CN112038589A (en) * 2019-06-04 2020-12-04 中国科学院物理研究所 High energy density aluminum secondary battery, positive electrode material thereof and preparation method

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