CN111403713A - Positive electrode material, positive plate and preparation method thereof, and lithium-sulfur battery - Google Patents

Positive electrode material, positive plate and preparation method thereof, and lithium-sulfur battery Download PDF

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CN111403713A
CN111403713A CN202010228474.7A CN202010228474A CN111403713A CN 111403713 A CN111403713 A CN 111403713A CN 202010228474 A CN202010228474 A CN 202010228474A CN 111403713 A CN111403713 A CN 111403713A
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oxide
sulfide
positive electrode
sulfur
electrode material
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吕伟
张玢
罗冲
杨全红
康飞宇
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Shenzhen International Graduate School of Tsinghua University
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Shenzhen International Graduate School of Tsinghua University
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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
    • H01M4/362—Composites
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0409—Methods of deposition of the material by a doctor blade method, slip-casting or roller coating
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0416—Methods of deposition of the material involving impregnation with a solution, dispersion, paste or dry powder
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of 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
    • H01M4/36—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
    • 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
    • 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

Abstract

A method for preparing a positive plate comprises the following steps: preparing an oxide/sulfide heterostructure by carrying out in-situ sulfidation reaction on an oxide and a sulfur source: the sulfur source is volatilized to form sulfur steam, and the sulfur steam is subjected to in-situ vulcanization reaction on the surface part of the oxide so as to vulcanize the surface part of the oxide into corresponding sulfide; uniformly mixing a conductive agent, a binder, a carbon-sulfur compound and an oxide/sulfide heterostructure to obtain a mixture; adding an organic solvent into the mixture, and uniformly mixing the mixture and the organic solvent to obtain a positive electrode material; and loading the positive electrode material on a current collector to obtain the positive electrode plate. The invention also relates to a positive electrode material, a positive plate and a lithium-sulfur battery. The positive electrode material, the positive plate, the preparation method of the positive plate and the lithium sulfur battery provided by the invention have good polysulfide adsorption performance, can promote polysulfide conversion, can finally improve the reaction kinetics and electrochemical performance of the lithium sulfur battery, and have simple synthesis process.

Description

Positive electrode material, positive plate and preparation method thereof, and lithium-sulfur battery
Technical Field
The invention relates to the field of lithium-sulfur batteries, in particular to a positive electrode material, a positive plate, a preparation method of the positive plate and a lithium-sulfur battery.
Background
Lithium sulfur batteries are expected to become the next generation of energy storage batteries because of their higher theoretical capacity, low cost of sulfur sources, and environmental friendliness. However, the lithium-sulfur battery has poor cycle performance and low sulfur utilization. The reason is that sulfur and lithium can generate polysulfide in the process of charge-discharge reaction, high-order multi-chain polysulfide can be dissolved in lithium-sulfur electrolyte, and the polysulfide is shuttled to the negative electrode through the diaphragm after being dissolved and reacts with the lithium to generate lithium sulfide, the sulfur source loss is caused by the polysulfide shuttle, and the utilization rate of sulfur is low. Low-order polysulfides are poorly conductive and coat the surface of the positive electrode material resulting in the appearance of "dead sulfur". These problems all result in poor cycle performance and poor high rate performance of lithium-sulfur batteries, and many researchers have developed many additives such as oxides, sulfides, phosphides, nitrides, and heterostructures of these materials in order to solve the above problems. These additives, particularly heterostructure additives, are capable of adsorbing polysulfides and accelerating the conversion of polysulfides, increasing the reaction kinetics of the cell. The existing synthesis process of the heterostructure additive is relatively complex.
Disclosure of Invention
In view of the above, the present invention provides a cathode material having good polysulfide adsorption performance and capable of promoting polysulfide conversion, and finally capable of improving reaction kinetics and electrochemical performance of a lithium sulfur battery, and having a simple synthesis process.
It is also necessary to provide a positive electrode sheet to which the positive electrode material as described above is applied.
It is also necessary to provide a method for producing the positive electrode sheet as described above.
There is also a need to provide a lithium sulfur battery using the positive electrode sheet as described above.
The positive electrode material comprises a conductive agent, a binder, a carbon-sulfur compound and an additive, wherein the additive is an oxide/sulfide heterostructure, the oxide/sulfide heterostructure is prepared from an oxide and a sulfur source through an in-situ vulcanization reaction, the sulfur source volatilizes to form sulfur vapor, and the sulfur vapor performs the in-situ vulcanization reaction on the surface part of the oxide to partially vulcanize the surface part of the oxide into a corresponding sulfide, so that the oxide/sulfide heterostructure is generated.
Further, the morphology of the oxide/sulfide heterostructure is granular or lamellar; the particle diameter of the oxide/sulfide heterostructure is 10nm-700 μm; in the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is from 1:20 to 20: 1.
Further, the additive accounts for 1-10% of the positive electrode material by mass, the carbon-sulfur compound accounts for 60-99.9% of the positive electrode material by mass, the conductive agent accounts for 0.1-20% of the positive electrode material by mass, and the binder accounts for 0.1-20% of the positive electrode material by mass.
Further, the oxide is at least one of tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide; the sulfide is at least one of tungsten sulfide, molybdenum sulfide, iron sulfide, titanium sulfide, cobalt sulfide, vanadium sulfide, manganese sulfide, tin sulfide, zirconium sulfide, magnesium sulfide, lanthanum sulfide, cesium sulfide, cerium sulfide and copper sulfide.
Further, the binder is at least one of polyvinylidene fluoride, polyethylene oxide, polyvinyl chloride, polyvinylidene fluoride-hexafluoropropylene, carboxymethyl cellulose, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium alginate and sodium polyacrylate; the conductive agent is a carbon material; the carbon in the carbon-sulfur compound is at least one of a one-dimensional carbon tube and two-dimensional graphene, the sulfur in the carbon-sulfur compound is elemental sulfur, and the elemental sulfur accounts for 50-98% of the carbon-sulfur compound by mass.
A positive electrode sheet comprising a current collector, said positive electrode sheet further comprising a positive electrode material as described above, said positive electrode material being supported on or in said current collector.
A method for preparing a positive plate comprises the following steps: preparing an oxide/sulfide heterostructure; the oxide/sulfide heterostructure is prepared by an in-situ sulfidation reaction of an oxide and a sulfur source, the sulfur source volatizes to form sulfur vapor, the sulfur vapor undergoes an in-situ sulfidation reaction at a surface portion of the oxide to sulfidize the surface portion of the oxide to a corresponding sulfide, thereby producing the oxide/sulfide heterostructure; the oxide/sulfide heterostructure is an additive; providing a conductive agent, a binder and a carbon-sulfur compound, and uniformly mixing the conductive agent, the binder and the carbon-sulfur compound with the oxide/sulfide heterostructure to obtain a mixture; adding an organic solvent into the mixture and uniformly mixing the mixture and the organic solvent to obtain a positive electrode material; and loading the positive electrode material on a current collector to obtain the positive electrode plate.
Further, preparing the oxide/sulfide heterostructure comprises the steps of: weighing an oxide and a sulfur source according to a certain mass ratio, and respectively placing the oxide and the sulfur source into a heat treatment container; vacuumizing the heat treatment container and filling protective atmosphere; the mass ratio of the oxide to the sulfur source is 1:10-10: 1; and heat-treating the oxide and the sulfur source in a vacuum environment and a protective atmosphere.
Further, the heat treatment process comprises the following steps: heating the heat treatment container to 250 ℃ and 400 ℃ at a heating rate of 1-10 ℃/min, and preserving the heat for 0.5-4 hours; heating to 400-700 ℃ at a heating rate of 1-10 ℃/min, and keeping the temperature for 0.5-4 hours to obtain the oxide/sulfide heterostructure material.
Further, the oxide is at least one of tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide; the sulfur source is at least one of sublimed sulfur powder, nano sulfur powder, thioacetamide, sodium sulfide or thiourea.
Further, the morphology of the oxide/sulfide heterostructure is granular or lamellar; the particle diameter of the oxide/sulfide heterostructure is 10nm-700 μm; in the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is 1:20 to 20: 1.
Further, the oxide/sulfide heterostructure accounts for 1-10% of the positive electrode material by mass, the carbon-sulfur composite accounts for 60-99.9% of the positive electrode material by mass, the conductive agent accounts for 0.1-20% of the positive electrode material by mass, and the binder accounts for 0.1-20% of the positive electrode material by mass.
Further, the loading manner includes at least one of knife coating, extrusion coating, dip coating, roll coating, spin coating, pouring, and injection.
A lithium-sulfur battery comprising a lithium negative electrode, a separator, an electrolyte and a battery case, said lithium-sulfur battery further comprising the positive plate of claim 6, said electrolyte being located in said battery case, said positive plate, said lithium negative electrode and said separator being immersed in said electrolyte, said separator being located between said positive plate and said lithium negative electrode.
According to the positive electrode material, the positive electrode plate, the preparation method of the positive electrode plate and the lithium-sulfur battery, 1) the surface part of oxide particles is vulcanized into corresponding sulfides by an in-situ vulcanization method to prepare an oxide sulfide heterostructure, the heterostructure with different shapes and structures and different mass ratios of oxides and sulfides can be prepared by controlling the conditions of vulcanization heat treatment and the mass ratio of a sulfur source to the oxides, and the preparation process is simple; 2) the oxide sulfide heterostructure is used as a catalyst of a positive electrode material, has a very good chemical adsorption effect on polysulfide generated in the charging and discharging processes of the lithium-sulfur battery, and can promote the conversion between sulfur and the polysulfide and between the polysulfide and lithium sulfide, so that the reaction kinetics and the electrochemical performance of the lithium-sulfur battery are improved finally.
Drawings
FIG. 1 shows WO provided by the present invention3、3WO3-1WS2、1WO3-2WS2、WS2A topography scan of.
FIG. 2 is WO3、3WO3-1WS2、1WO3-2WS2、WS2The phase analysis (X-ray diffraction) chart of (1).
FIG. 3 is WO3、3WO3-1WS2、1WO3-2WS2、WS2Rate diagram of lithium-sulfur battery as positive electrode material.
FIG. 4 is WO3、3WO3-1WS2、1WO3-2WS2、WS2Cycle performance of lithium-sulfur batteries as positive electrode materials.
Detailed Description
In order to further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description will be given to specific embodiments, structures, features and effects of the positive electrode material, the positive electrode sheet, the method for preparing the positive electrode sheet and the lithium-sulfur battery provided by the present invention in combination with preferred embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The invention provides a lithium-sulfur battery which comprises a lithium negative electrode, a positive plate, a diaphragm, electrolyte and a battery shell, wherein the electrolyte is positioned in the battery shell, the positive plate, the lithium negative electrode and the diaphragm are immersed in the electrolyte, and the diaphragm is positioned between the positive plate and the lithium negative electrode.
The positive plate comprises a current collector and a positive material, and the positive material is loaded on or in the current collector.
The positive electrode material comprises a conductive agent, a binder, a carbon-sulfur compound and an additive, wherein the additive is an oxide/sulfide heterostructure.
The oxide/sulfide heterostructure is prepared by carrying out in-situ vulcanization reaction on an oxide and a sulfur source in a vacuum-pumping environment and a protective atmosphere.
In particular, the sulfur source is gasified to sulfur vapor that undergoes an in situ sulfidation reaction at the surface of the oxide to partially sulfidize the oxide surface to the corresponding sulfide to produce the oxide/sulfide heterostructure.
The mass percentage of the additive in the positive electrode material is 1-10%, the mass percentage of the carbon-sulfur compound in the positive electrode material is 60-99.9%, the mass percentage of the conductive agent in the positive electrode material is 0.1-20%, and the mass percentage of the binder in the positive electrode material is 0.1-20%.
Wherein the oxide/sulfide heterostructure is granular or lamellar in morphology.
Wherein the particle diameter of the oxide/sulfide heterostructure is in the range of 10nm to 700 μm.
In the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is from 1:20 to 20: 1.
Wherein the oxide is in the form of particles or flakes. When the oxide is in the form of particles, the diameter of the oxide particles is 10nm to 300 nm.
Wherein the oxide is at least one of oxides such as tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide.
Wherein the sulfide is at least one of sulfides such as tungsten sulfide, molybdenum sulfide, iron sulfide, titanium sulfide, cobalt sulfide, vanadium sulfide, manganese sulfide, tin sulfide, zirconium sulfide, magnesium sulfide, lanthanum sulfide, cesium sulfide, cerium sulfide and copper sulfide.
Wherein the sulfur source is at least one of sublimed sulfur powder, nano sulfur powder, thioacetamide, sodium sulfide or thiourea and the like.
Wherein the binder is at least one of polyvinylidene fluoride, polyethylene oxide, polyvinyl chloride, polyvinylidene fluoride-hexafluoropropylene, carboxymethyl cellulose, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium alginate, sodium polyacrylate, etc.
Wherein the conductive agent is a carbon material. Specifically, the conductive agent is one of a carbon black conductive agent (Super P), a porous activated carbon conductive agent, a graphene conductive agent, a carbon nanotube conductive agent, and the like.
The carbon-sulfur compound is formed by compounding carbon and elemental sulfur through a hot melting method. Specifically, the temperature of the hot melting is 150-230 ℃.
The carbon in the carbon-sulfur compound can be a one-dimensional carbon tube, two-dimensional graphene or other carbon materials, and the sulfur in the carbon-sulfur compound is elemental sulfur.
Wherein the mass percentage of the elemental sulfur in the carbon-sulfur compound is 50-98%.
The invention also provides a preparation method of the oxide/sulfide heterostructure, which comprises the following steps:
step S1, weighing oxide and sulfur source in a certain mass ratio, respectively placing the oxide and sulfur source into a heat treatment container, vacuumizing the heat treatment container, and filling protective atmosphere into the heat treatment container.
Step S2, heat-treating the oxide and sulfur source in a vacuum environment and a protective atmosphere. Wherein during the heat treatment the sulphur source is volatilised to form sulphur vapour which undergoes an in situ sulphidation reaction at a surface portion of the oxide to sulphide the oxide surface portion to the corresponding sulphide to produce the oxide/sulphide heterostructure.
Wherein the reaction principle of the in-situ vulcanization reaction is as follows: the sulfur source is utilized to sublimate at a certain temperature to generate sulfur vapor, the sulfur vapor reacts with the oxide to generate corresponding sulfide, and the oxide is converted into the corresponding sulfide from outside to inside. By controlling the vulcanization temperature, time and the ratio of the sulfur source to the oxide, the heterostructure compounds with different morphologies and different mass ratios of oxide sulfides can be obtained.
Wherein, in step S1, the mass ratio of the oxide to the sulfur source is 1:10-10: 1.
In step S1, the oxide and the sulfur source are respectively loaded into a boat, and then the two boats loaded with the oxide and the sulfur source are placed in a tube furnace, and the tube furnace is sealed. Preferably, the tube furnace is a quartz tube furnace.
Wherein, in step S1, the evacuating occurs after sealing the tube furnace. In this embodiment, the evacuation and the filling of the protective atmosphere are repeated three times. In this embodiment, the protective atmosphere is argon. Wherein the evacuation prevents volatilization of sulfur vapor, thereby improving the utilization rate of the sulfur source.
Wherein the oxide is in the form of particles or flakes. When the oxide is in the form of particles, the diameter of the particles of the oxide is 10nm to 300 nm.
Wherein the oxide is at least one of oxides such as tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide.
Wherein the sulfur source is at least one of sublimed sulfur powder, nano sulfur powder, thioacetamide, sodium sulfide or thiourea and the like.
Wherein, in step S2, the heat treatment process is as follows: firstly, heating the heat treatment container to 250-400 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 0.5-4 hours (low-temperature heat preservation); secondly, heating to 400-700 ℃ at a heating rate of 1-10 ℃/min, and preserving the temperature for 0.5-4 hours to obtain the oxide/sulfide heterostructure material.
Wherein, in the heat treatment process, the low-temperature heat preservation is firstly carried out for a period of time, and the following advantages are achieved: during the low-temperature heat preservation process, the sulfur source can react with the oxide to form crystal nuclei, and during the subsequent temperature rise process, the crystal nuclei continue to grow, so that granular or lamellar sulfides are produced on the surface of the oxide through vulcanization. Therefore, the low-temperature heat preservation process ensures that crystal nuclei can be uniformly formed on the surface of the oxide, and further ensures that the sulfide crystal nuclei uniformly grow on the surface of the oxide in the subsequent temperature rise process.
In the heat treatment process, the relatively slow temperature rise rate (1-10 ℃/min) is adopted for temperature rise so as to ensure that sulfur vapor can fully react with oxides.
Wherein the oxide/sulfide heterostructure is granular or lamellar in morphology.
Wherein, when the oxide/sulfide heterostructure is in a granular form, the oxide/sulfide heterostructure has a particle diameter of 10nm to 700 μm.
Wherein, in the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is 1:20 to 20: 1.
Wherein the sulfide is at least one of sulfides such as tungsten sulfide, molybdenum sulfide, iron sulfide, titanium sulfide, cobalt sulfide, vanadium sulfide, manganese sulfide, tin sulfide, zirconium sulfide, magnesium sulfide, lanthanum sulfide, cesium sulfide, cerium sulfide and copper sulfide.
In this embodiment, the oxide/sulfide heterostructure is WO3/WS2A heterostructure.
Among them, the oxide/sulfide heterostructure prepared by in-situ sulfidation reaction has good adsorption capacity for polysulfide and can promote conversion between polysulfides.
The invention also provides a preparation method of the cathode material, which comprises the following steps:
step S21, an oxide/sulfide heterostructure is prepared by the above method of preparing an oxide/sulfide heterostructure.
Step S22, providing a conductive agent, a binder, and a carbon-sulfur composite, and uniformly mixing the conductive agent, the binder, the carbon-sulfur composite, and the oxide/sulfide heterostructure to obtain a mixture.
And step S23, adding an organic solvent into the mixture and uniformly mixing the mixture and the organic solvent to obtain a positive electrode material.
Wherein the oxide/sulfide heterostructure acts as an additive to the positive electrode material. When the oxide/sulfide heterostructure is used as an additive of the cathode material of the lithium sulfur battery, the oxide/sulfide heterostructure can improve the electrochemical redox kinetics of the lithium sulfur battery and improve the utilization rate of sulfur, thereby increasing the electrochemical performance of the cathode material.
In step S22, the oxide/sulfide heterostructure accounts for 1% to 10% by mass of the positive electrode material, the carbon-sulfur composite accounts for 60% to 99.9% by mass of the positive electrode material, the conductive agent accounts for 0.1% to 20% by mass of the positive electrode material, and the binder accounts for 0.1% to 20% by mass of the positive electrode material.
Wherein, in step S22, the binder is at least one of polyvinylidene fluoride, polyethylene oxide, polyvinyl chloride, polyvinylidene fluoride-hexafluoropropylene, carboxymethyl cellulose, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium alginate, and sodium polyacrylate.
Wherein, in step S22, the conductive agent is a carbon material. Specifically, the conductive agent is one of a carbon black conductive agent (Super P), a porous activated carbon conductive agent, a graphene conductive agent, a carbon nanotube conductive agent, and the like.
In step S22, the carbon-sulfur composite is formed by compounding carbon and elemental sulfur by a hot melting method. Specifically, the temperature of the hot melting is 150-230 ℃. The carbon in the carbon-sulfur compound can be a one-dimensional carbon tube, two-dimensional graphene or other carbon materials, and the sulfur in the carbon-sulfur compound is elemental sulfur. The mass percentage of the elemental sulfur in the carbon-sulfur compound is 50-98%.
In step S23, the solvent is an organic solvent such as N-methylpyrrolidone or dimethylformamide.
Wherein, in step S23, the mass ratio between the solvent and the mixture (the conductive agent, the binder, the carbon-sulfur composite and the oxide/sulfide heterostructure) is 1:100-100: 1.
In step S23, the mixture is stirred for 5 to 12 hours.
The invention also provides a preparation method of the positive plate, which comprises the following steps:
and step S31, preparing the cathode material by adopting the method for preparing the cathode material.
Step S32, the positive electrode material is loaded on a current collector.
And step S33, drying the current collector loaded with the positive electrode material to obtain the positive electrode plate.
Wherein, in step S32, the current collector is a metal current collector. In the present embodiment, an aluminum foil or a carbon-coated aluminum foil is used as the current collector.
In step S32, the loading method includes at least one of blade coating, extrusion coating, dip coating, roll coating, spin coating, pouring, and injection.
Wherein, in step S33, the drying time is 8-20 hours.
The invention also provides a preparation method of the lithium-sulfur battery, which comprises the following steps:
and step S41, preparing the positive plate by adopting the preparation method of the positive plate.
Step S42, providing a lithium negative electrode, a diaphragm, electrolyte and a battery case, putting the electrolyte into the battery case, immersing the positive plate, the lithium negative electrode and the diaphragm into the electrolyte, and positioning the diaphragm between the positive plate and the lithium negative electrode to obtain the lithium-sulfur battery.
Wherein, between the step S41 and the step S42, the method further comprises the following steps: the positive electrode sheet obtained in step S41 is die-cut into an appropriate size.
In step S42, the separator is made of polyethylene or polypropylene.
The present invention will be specifically described below with reference to examples and comparative examples.
Example 1:
this example is described in WO3/WS2Preparation of heterostructures is an example.
(1) Weighing 4g of thiourea powder into one corundum ark, and weighing 1g of tungsten oxide powder into the other corundum ark.
(2) And sequentially placing the thiourea ark and the tungsten oxide ark into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 400 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. The obtained powder was 3WO3-1WS2A heterostructure. The topography scan is as in FIG. 1b picture, phase analysis is 3WO in figure 23-1WS2。
(5) And mechanically and uniformly mixing the graphene and the sulfur powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Mixing the conductive carbon, the adhesive and the 3WO obtained in the step (4)3-1WS2Stirring the heterostructure powder and the carbon-sulfur compound obtained in the step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; among them, WO3/WS2The contents of the heterostructure, the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-3WO3-1WS2。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, lithium sulfur electrolyte and the like into a lithium sulfur battery, and carrying out electrochemical test on the lithium sulfur battery. The test results are shown in 3WO in FIGS. 3 and 43-1WS2。
Example 2:
this example is described in WO3/WS2Preparation of heterostructures is an example.
(1) Weighing 4g of thiourea powder into one corundum ark, and weighing 1g of tungsten oxide powder into the other corundum ark.
(2) And sequentially placing the thiourea ark and the tungsten oxide ark into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 500 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. To obtainIs 1WO3-2WS2A heterostructure. The topography scan is shown in fig. 1, panel c, and the phase analysis is shown in fig. 2, panel 1WO3-2WS2。
(5) And mechanically and uniformly mixing the graphene and the sulfur powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Mixing the conductive carbon, the adhesive and the 1WO obtained in the step (4)3-2WS2Stirring the heterostructure powder and the carbon-sulfur compound obtained in the step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; in which WO3/WS2The contents of the heterostructure, the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-1WO3-2WS2。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, lithium sulfur electrolyte and the like into a lithium sulfur battery, and carrying out electrochemical test on the lithium sulfur battery. The test results are shown in FIGS. 3 and 4 as 1WO3-2WS2。
Example 3:
this example illustrates the preparation of tungsten oxide.
(1) 1g of tungsten oxide powder was weighed into a corundum ark.
(2) And sequentially placing the tungsten oxide boats into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 600 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. The obtained powder was WO3. The topography scan is shown as a in FIG. 1, and the phase analysis is shown as WO in FIG. 23。
(5) And mechanically and uniformly mixing the graphene and the sulfur powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Mixing the conductive carbon, the binder and the WO obtained in the step (4)3Stirring the powder and the carbon-sulfur compound obtained in the step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; wherein the contents of the WO, the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-WO3。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, lithium sulfur electrolyte and the like into a lithium sulfur battery, and carrying out electrochemical test on the lithium sulfur battery. The test results are shown in WO of FIGS. 3 and 43。
Example 4:
in this example WS2The preparation of (2) is exemplified.
(1) 11g of thiourea powder was weighed into one corundum ark, and 1g of tungsten oxide powder was weighed into the other corundum ark.
(2) And sequentially placing the thiourea ark and the tungsten oxide ark into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 400 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. The powder obtained is WS2. The topography scan is shown as d in FIG. 1, and the phase analysis is shown as WS in FIG. 22。
(5) And mechanically and uniformly mixing the graphene powder and the thiourea powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Mixing the conductive carbon, the adhesive and the WS obtained in the step (4)2Stirring the powder and the carbon-sulfur compound obtained in the step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; wherein WS2The contents of the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-WS2。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, lithium sulfur electrolyte and the like into a lithium sulfur battery, and carrying out electrochemical test on the lithium sulfur battery. Test results are as WS in FIGS. 3 and 42。
Example 5:
this example is described in WO3/WS2Preparation of heterostructures is an example.
(1) 4g of sulfur powder is weighed and put into one corundum ark, and 1g of tungsten oxide powder is weighed and put into the other corundum ark.
(2) And sequentially placing the sulfur powder square boat and the tungsten oxide square boat into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 400 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. The powder obtained is WO3-WS2-5 heterostructure.
(5) And mechanically and uniformly mixing the graphene and the sulfur powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Mixing the conductive carbon, the binder and the WO obtained in the step (4)3-WS2-5 stirring the heterostructure powder and the carbon-sulfur complex obtained in step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; among them, WO3/WS2The contents of the heterostructure, the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-WO3-WS2-5。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, a lithium sulfur electrolyte and the like into the lithium sulfur battery.
Example 6:
this example is described in WO3/WS2Preparation of heterostructures is an example.
(1) 8g of sulfur powder is weighed and put into one corundum ark, and 1g of tungsten oxide powder is weighed and put into the other corundum ark.
(2) And sequentially placing the sulfur powder square boat and the tungsten oxide square boat into a central temperature area of the quartz tube.
(3) And vacuumizing by using a vacuum pump, filling argon, vacuumizing again, and vacuumizing the quartz tube to a vacuum state after repeating for three times.
(4) The tube furnace is heated to 350 ℃ at the heating rate of 2 ℃/min and is kept for 1.5 hours. Then heating to 400 ℃ at the heating rate of 10 ℃/min and preserving the heat for 1.5 hours. Finally, the tube furnace was purged with argon for thirty minutes. The powder obtained is WO3-WS2-6 heterostructure.
(5) And mechanically and uniformly mixing the graphene and the sulfur powder according to the mass ratio of 3:7, and preserving the heat of the mixed powder at 155 ℃ for 12 hours to obtain the carbon-sulfur compound.
(6) Will be provided withConductive carbon, binder and WO obtained in step (4)3-WS2-6 stirring the heterostructure powders and the carbon-sulfur complex obtained in step (5) together to obtain a mixture; then, dropwise adding an N-methyl pyrrolidone solvent into the mixture and stirring for 8 hours to obtain a positive electrode material; among them, WO3/WS2The contents of the heterostructure, the carbon-sulfur compound, the conductive carbon and the binder are respectively 5mg, 75mg, 10mg and 10mg, and the content of the solvent is 1 ml.
(7) Loading the positive electrode material obtained in the step (6) on a current collector in a blade coating mode to obtain a positive electrode plate, drying the positive electrode plate at 60 ℃ for 12 hours, punching the dried electrode plate into a proper size, and marking the punched positive electrode plate as S-WO3-WS2-6。
(8) And assembling the punched positive plate, a diaphragm, a lithium negative electrode, a lithium sulfur electrolyte and the like into the lithium sulfur battery.
Please refer to FIG. 1, FIG. 1 is WO3、3WO3-1WS2、1WO3-2WS2、WS2A topography scan of. As can be seen from fig. 1: after in-situ vulcanization, the surfaces of the tungsten oxide particles in the graph a are vulcanized into lamellar sulfides (see a b), the lamellar layers increase with the increase of the vulcanization degree (see a c), and all tungsten oxide is converted into tungsten sulfide when the vulcanization is complete (see a d).
Please refer to fig. 2, fig. 2 is WO3、3WO3-1WS2、1WO3-2WS2、WS2The phase analysis (X-ray diffraction) chart of (1). As can be seen from fig. 1: pure WO3After partial vulcanization, a (002) peak of tungsten disulfide appears obviously, which proves that the partial tungsten oxide structure is changed into tungsten sulfide, and then 3WO is formed3：1WS2Heterostructure, WS with increasing degree of sulfurization2The peak intensity of (A) becomes strong, and 1WO is produced3：2WS2Heterostructures, with increasing degree of sulfurization, WO3The peak of (A) was almost completely disappeared, and from this, WO3All being converted to WS2。
Please refer to fig. 3, fig. 3 is WO3、3WO3-1WS2、1WO3-2WS2、WS2Rate diagram of lithium-sulfur battery as positive electrode material. As can be seen from fig. 3: containing pure WO3The battery rate performance of (1) is the worst, and the battery rate performance of the best battery contains 3WO3：1WS2Of a partially vulcanized WO31WO with better rate capability and secondly most of vulcanization3：2WS2The properties may be reduced when the material is fully cured.
Please refer to FIG. 4, FIG. 4 is WO3、3WO3-1WS2、1WO3-2WS2、WS2Cycle performance of lithium-sulfur batteries as positive electrode materials. As can be seen from fig. 4: containing pure WO3The battery of (1) is the worst in cycle performance, and the best battery contains 3WO3：1WS2The battery of (1) demonstrates that the partially sulfided tungsten oxide has better cycle performance, followed by the mostly sulfided 1WO3：2WS2When the material is fully cured, the cycle performance may be reduced.
According to the positive electrode material, the positive electrode plate, the preparation method of the positive electrode plate and the lithium-sulfur battery, 1) the surface part of oxide particles is vulcanized into corresponding sulfides by an in-situ vulcanization method to prepare an oxide sulfide heterostructure, the heterostructure with different shapes and structures and different mass ratios of oxides and sulfides can be prepared by controlling the conditions of vulcanization heat treatment and the mass ratio of a sulfur source to the oxides, and the preparation process is simple; 2) the oxide sulfide heterostructure is used as a catalyst of a positive electrode material, has a very good chemical adsorption effect on polysulfide generated in the charging and discharging processes of the lithium-sulfur battery, and can promote the conversion between sulfur and the polysulfide and between the polysulfide and lithium sulfide, so that the reaction kinetics and the electrochemical performance of the lithium-sulfur battery are improved finally.
Although the present invention has been described with reference to the above preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (14)

1. A positive electrode material comprises a conductive agent, a binder, a carbon-sulfur compound and an additive, and is characterized in that the additive is an oxide/sulfide heterostructure, the oxide/sulfide heterostructure is prepared by an in-situ vulcanization reaction of an oxide and a sulfur source, the sulfur source volatilizes to form sulfur vapor, and the sulfur vapor carries out the in-situ vulcanization reaction on the surface part of the oxide to partially vulcanize the surface part of the oxide into a corresponding sulfide, so that the oxide/sulfide heterostructure is generated.
2. The positive electrode material according to claim 1, wherein the oxide/sulfide heterostructure is granular or lamellar in morphology; the particle diameter of the oxide/sulfide heterostructure is 10nm-700 μm; in the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is from 1:20 to 20: 1.
3. The positive electrode material according to claim 1, wherein the additive accounts for 1 to 10 mass% of the positive electrode material, the carbon-sulfur composite accounts for 60 to 99.9 mass% of the positive electrode material, the conductive agent accounts for 0.1 to 20 mass% of the positive electrode material, and the binder accounts for 0.1 to 20 mass% of the positive electrode material.
4. The positive electrode material according to claim 1, wherein the oxide is at least one of tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide; the sulfide is at least one of tungsten sulfide, molybdenum sulfide, iron sulfide, titanium sulfide, cobalt sulfide, vanadium sulfide, manganese sulfide, tin sulfide, zirconium sulfide, magnesium sulfide, lanthanum sulfide, cesium sulfide, cerium sulfide and copper sulfide.
5. The positive electrode material according to claim 1, wherein the binder is at least one of polyvinylidene fluoride, polyethylene oxide, polyvinyl chloride, polyvinylidene fluoride-hexafluoropropylene, carboxymethyl cellulose, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium alginate, and sodium polyacrylate; the conductive agent is a carbon material; the carbon in the carbon-sulfur compound is at least one of a one-dimensional carbon tube and two-dimensional graphene, the sulfur in the carbon-sulfur compound is elemental sulfur, and the elemental sulfur accounts for 50-98% of the carbon-sulfur compound by mass.
6. A positive electrode sheet comprising a current collector, characterized in that the positive electrode sheet further comprises a positive electrode material according to any one of claims 1 to 5, the positive electrode material being supported on or in the current collector.
7. A method for preparing a positive plate comprises the following steps:
preparation of oxide/sulfide heterostructures: the oxide/sulfide heterostructure is prepared by carrying out in-situ sulfidation reaction on an oxide and a sulfur source, wherein the sulfur source volatilizes to form sulfur vapor, and the sulfur vapor carries out in-situ sulfidation reaction on the surface part of the oxide to sulfide the surface part of the oxide into a corresponding sulfide, so that the oxide/sulfide heterostructure is generated; the oxide/sulfide heterostructure is an additive;
providing a conductive agent, a binder and a carbon-sulfur compound, and uniformly mixing the conductive agent, the binder and the carbon-sulfur compound with the oxide/sulfide heterostructure to obtain a mixture;
adding an organic solvent into the mixture and uniformly mixing the mixture and the organic solvent to obtain a positive electrode material; and
and loading the positive electrode material on a current collector to obtain the positive electrode plate.
8. The method for producing a positive electrode sheet according to claim 7, wherein the production of the oxide/sulfide heterostructure includes the steps of:
weighing an oxide and a sulfur source according to a certain mass ratio, and respectively placing the oxide and the sulfur source into a heat treatment container; vacuumizing the heat treatment container and filling protective atmosphere; the mass ratio of the oxide to the sulfur source is 1:10-10: 1; and
and heat treating the oxide and the sulfur source in a vacuum environment and a protective atmosphere.
9. The method for producing a positive electrode sheet according to claim 8, wherein the heat treatment is carried out by:
heating the heat treatment container to 250-400 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 0.5-4 hours;
heating to 400-700 ℃ at a heating rate of 1-10 ℃/min, and keeping the temperature for 0.5-4 hours to obtain the oxide/sulfide heterostructure material.
10. The method for producing a positive electrode sheet according to claim 8, wherein the oxide is at least one of tungsten oxide, molybdenum oxide, iron oxide, titanium oxide, cobalt oxide, vanadium oxide, manganese oxide, tin oxide, zirconium oxide, magnesium oxide, lanthanum oxide, cesium oxide, cerium oxide, and copper oxide; the sulfur source is at least one of sublimed sulfur powder, nano sulfur powder, thioacetamide, sodium sulfide or thiourea.
11. The method for producing a positive electrode sheet according to claim 8, wherein the morphology of the oxide/sulfide heterostructure is granular or lamellar; the particle diameter of the oxide/sulfide heterostructure is 10nm-700 μm; in the oxide/sulfide heterostructure, the mass ratio of the sulfide to the oxide is 1:20 to 20: 1.
12. The method for preparing the positive electrode sheet according to claim 8, wherein the oxide/sulfide heterostructure accounts for 1 to 10 mass% of the positive electrode material, the carbon-sulfur composite accounts for 60 to 99.9 mass% of the positive electrode material, the conductive agent accounts for 0.1 to 20 mass% of the positive electrode material, and the binder accounts for 0.1 to 20 mass% of the positive electrode material.
13. The method for producing a positive electrode sheet according to claim 8, wherein the supporting means includes at least one of knife coating, extrusion coating, dip coating, roll coating, spin coating, pouring, and injection.
14. A lithium-sulfur battery, comprising a lithium negative electrode, a diaphragm, electrolyte and a battery case, wherein the lithium-sulfur battery further comprises the positive plate of claim 6, the electrolyte is located in the battery case, the positive plate, the lithium negative electrode and the diaphragm are immersed in the electrolyte, and the diaphragm is located between the positive plate and the lithium negative electrode.
CN202010228474.7A 2020-03-27 2020-03-27 Positive electrode material, positive plate and preparation method thereof, and lithium-sulfur battery Pending CN111403713A (en)

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