CN113764624A - Preparation method of high-performance lithium-sulfur battery positive plate with gradient structure - Google Patents

Preparation method of high-performance lithium-sulfur battery positive plate with gradient structure Download PDF

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CN113764624A
CN113764624A CN202111093108.6A CN202111093108A CN113764624A CN 113764624 A CN113764624 A CN 113764624A CN 202111093108 A CN202111093108 A CN 202111093108A CN 113764624 A CN113764624 A CN 113764624A
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positive plate
carbon
sulfur
lithium
gradient structure
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张卫华
姚大勇
周少华
王是杰
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Xian University of Technology
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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
    • H01M4/13—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
    • 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
    • H01M4/36—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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/10—Energy storage using batteries

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Abstract

The invention discloses a preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure, which takes conductive carbon as a conductive agent, a high-molecular polymer as a binder and an organic solvent or deionized water as a solvent to synthesize conductive carbon slurry; then coating the conductive carbon slurry on the surface of the S/C positive plate, and drying to obtain a carbon coating film; and then regulating and controlling the active sulfur sublimation and desublimation processes of the S/C layer of the positive plate by carrying out heat treatment on the S/C positive plate with the carbon coating layer film under certain atmosphere, temperature and time to prepare the lithium-sulfur battery positive plate with the gradient structure, wherein the sulfur carrying amount from the positive plate to the carbon coating layer is reduced in sequence. Through the preparation and heat treatment of the carbon coating film, the S/C interface combination is improved, the effective capacity of the electrolyte on the positive electrode side is improved, the dissolution loss of lithium polysulfide is inhibited, the reservation of the pore space of the conductive carbon network is realized, the volume expansion in the electrochemical reaction process is slowly released, and the high rate performance and the circulation capacity retention rate of the positive electrode material are obviously improved.

Description

Preparation method of high-performance lithium-sulfur battery positive plate with gradient structure
Technical Field
The invention belongs to the technical field of manufacturing of high-performance lithium-sulfur batteries, and particularly relates to a preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure.
Background
The theoretical specific capacity of active sulfur of the positive electrode of the lithium-sulfur battery reaches 1675mAh/g, the mass specific energy of the battery assembled with the lithium metal can reach 2500Wh/kg, and the lithium-sulfur battery has the characteristics of no toxicity, low price, environmental friendliness and the like, and is the most potential secondary battery energy storage system of the next generation. However, the commercialization process is hindered, and among them, the destruction of the positive electrode structure is most prominent due to the easy dissolution loss of lithium polysulfide, which is an intermediate product generated during charge and discharge, and the volume expansion of the intermediate product generated during electrochemical process.
The existing lithium-sulfur battery positive plate is prepared by adopting S/C positive electrode material powder, conductive carbon, a binder, a dispersing solvent and the like to prepare positive electrode slurry, coating the positive electrode slurry on the surface of a confluence plate of aluminum foil and the like, drying and compacting the mixture, wherein the thickness of the positive electrode material coating is about 10 mu m to 70 mu m, the effective active sulfur substance loading mass is 50 percent to 70 percent, and the mass density is 2mg/cm2～6mg/cm2Because the volume expansion of the active sulfur product phase is 40-79% in the electrochemical reaction process, the interface combination and the structure damage of the S/C positive electrode material are serious, and the polysulfide lithium product in the electrochemical reaction process is easy to dissolve in the electrolyte, so that the active sulfur component in the positive electrode plate area is lost, the SEI film on the surface of the negative electrode plate is rapidly increased, the electrochemical performances such as charge-discharge specific capacity, high rate performance, capacity retention rate and the like are rapidly deteriorated along with the cycle number, and the method becomes the biggest obstacle to the commercial application of the lithium-sulfur battery.
Therefore, a novel positive plate structure is designed, polysulfide lithium can be restrained on the positive side as far as possible, and meanwhile, a certain pore space is reserved in the positive carbon network to buffer the volume expansion of the active sulfur intermediate product in the electrochemical reaction process, so that the novel positive plate structure is an effective solution.
Disclosure of Invention
The invention aims to provide a preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure, which solves the problems that an intermediate product polysulfide lithium generated in the charging and discharging processes of the conventional lithium-sulfur battery positive plate is easy to dissolve and run off, and the volume expansion of the intermediate product in the electrochemical process causes the damage of a positive structure.
The technical scheme adopted by the invention is as follows: a preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure comprises the steps of synthesizing conductive carbon slurry by using conductive carbon as a conductive agent, using a high-molecular polymer as a binder and using organic solvent or deionized water as a solvent; then coating the conductive carbon slurry on the surface of the sulfur/carbon positive plate, and drying to obtain a uniform carbon coating film; and then regulating and controlling the sulfur sublimation and desublimation processes of the S/C layer of the positive plate by heat treatment of the sulfur/carbon positive plate with the carbon coating layer to prepare the lithium-sulfur battery positive plate with the gradient structure, wherein the sulfur carrying amount from the positive plate to the carbon coating layer is reduced sequentially.
The present invention is also characterized in that,
a preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure comprises the following specific operation steps:
step 1, preparing conductive carbon slurry:
mixing conductive carbon, a binder and a solvent according to a mass ratio of 1: (0.5-2): (5-20) uniformly mixing to obtain conductive carbon slurry with the viscosity of 2000-6000 mPa & s;
step 2, preparing a carbon coating film:
coating the conductive carbon slurry on the surface of the sulfur/carbon positive plate, and drying in the atmosphere or protective atmosphere environment to obtain a conductive carbon coating layer positive plate with a carbon coating layer film;
step 3, heat treatment of the electrode slice with the gradient structure:
and (3) carrying out heat treatment on the conductive carbon coating layer positive plate in the atmosphere or protective atmosphere environment to obtain the lithium-sulfur battery positive plate with the sulfur carrying amount sequentially reduced from the positive plate to the carbon coating layer film, namely the positive plate with the gradient structure.
The preparation method of the sulfur/carbon positive plate comprises the following steps: preparing coating slurry by taking a sulfur/carbon anode material as a main body, and preparing the anode sheet on an aluminum foil or a copper foil by spraying and roller coating methods; the sulfur/carbon anode material is obtained by dissolving or depositing an active sulfur material on a conductive carrier which is carbon materials such as porous carbon, graphene, carbon nano tubes, expanded graphite, acetylene black, Ketjen black and the like.
The step 1 specifically comprises the following steps: the conductive carbon comprises one or a combination of several of acetylene black, super p, Ketjen black, graphene and carbon nanotubes; the binder comprises polyvinylidene fluoride (PVDF), cellulose (CMC) and a high polymer material of CMC-Na; the solvent comprises N-methylpyrrolidone (NMP) and deionized water.
And 2, the drying temperature range is 60-90 ℃, and the film thickness of the fully dried carbon coating film is 5-30 mu m.
Step 3, the heat treatment temperature is 100-120 ℃, and the heat treatment time is 0.3-2 h; the protective atmosphere refers to negative pressure and nitrogen atmosphere.
The preparation process principle is as follows: coating and preparing a carbon coating film with a certain thickness on the surface of the conventional lithium-sulfur battery positive plate, and well combining the carbon coating film with the existing S/C coating of the positive plate; and then, through heat treatment, the sublimation-desublimation process of the active sulfur is regulated and controlled, so that the active sulfur in the S/C coating is partially sublimated to form a certain proportion of reserved space, and the sulfur sublimation gas phase is mainly adsorbed, diffused and desublimated by conductive carbon and a cross-linked network framework in the carbon coating film in the process of passing through the carbon coating film, thereby forming gradient distribution of sulfur carrying amount on the cross section.
The principle for improving the electrochemical performance of the lithium-sulfur battery anode material is that the carbon coating film has rich conductive carbon and a cross-linked network structure, and can hold more electrolyte on the anode side, so that the high-rate charge-discharge specific capacitance can be improved, and the loss of polysulfide lithium in the electrochemical reaction process can be inhibited; in addition, due to the sublimation and diffusion of the appropriate active sulfur in the S/C coating, a certain proportion of space reservation can be formed, the volume expansion of a sulfur product phase in the subsequent electrochemical reaction can be alleviated, and the conductive network structure in the positive plate is stabilized, so that the improvement of the circulating capacity retention rate of the positive electrode material of the lithium-sulfur battery is facilitated, and the novel positive plate structure of the high-performance lithium-sulfur battery is provided.
The beneficial effect of the invention is that,
(1) based on the existing lithium-sulfur battery positive plate production process, the carbon coating film preparation process and the heat treatment process are added, the method is a technical route with good universality, is completely compatible with the existing lithium-sulfur battery production process, and can form good interface combination of the carbon coating film and the S/C positive plate.
(2) The sublimation, desublimation and diffusion processes of active sulfur in the S/C anode material are regulated and controlled through heat treatment temperature, time and atmosphere, so that gradient distribution of sulfur carrying capacity along the cross section is formed, the gradient structure realizes that a certain proportion of volume space (1/4-1/2 is theoretically required and needs to be determined according to actual conditions in application) is reserved in the S/C anode material on one hand, and on the other hand, the sublimation-desublimation phase transformation of the active sulfur at high temperature ensures good S/C interface combination in the S/C anode material and the conductive carbon coating film. Thereby avoiding the interface combination damage of the S/C anode material and the damage of the conductive network structure and improving the electrochemical performance of the lithium-sulfur battery.
(3) The carbon coating film on the surface of the positive plate is a stable and uniform conductive carbon network, contains rich pore structures and conductive frameworks, can adsorb and contain more electrolyte on one side of the positive plate, inhibits the dissolution loss of the polysulfide lithium to a diaphragm-negative electrode region in the electrochemical reaction process through physical confinement, and extends the coating space of the conductive network on the positive plate side, thereby being beneficial to charge transfer and conversion efficiency in the electrochemical reaction process and improving the charge-discharge specific capacity.
(4) The carbon coating film structure on the surface of the positive plate has the advantages that the film thickness can be adjusted according to actual needs, the sublimation gas phase of active sulfur can be adsorbed and deposited to the maximum extent in the subsequent high-temperature heat treatment process, and the pollution of the sublimation gas phase of sulfur to the environment and the loss of the loading amount of the active sulfur in the positive plate are avoided.
Drawings
FIG. 1 is a schematic diagram of the principle of the preparation process of a high-performance lithium-sulfur battery positive plate with a gradient structure.
FIG. 2 is an SEM image of a lithium-sulfur battery positive plate with a gradient structure obtained in example 1 of the present invention and an EDS image thereof.
FIG. 3 is an SEM image of a lithium-sulfur battery positive plate with a gradient structure obtained in example 2 of the invention and an EDS image thereof.
FIG. 4 is a graph of the electrochemical impedance EIS of lithium sulfur button half cells of examples 1 and 2 of the present invention.
Fig. 5 is a discharge specific capacity cycle test curve diagram of lithium-sulfur button half cells in examples 1 and 2 of the present invention under different rate conditions.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The preparation method of the high-performance lithium-sulfur battery positive plate with the gradient structure comprises the following specific operation steps:
step 1, preparing conductive carbon slurry:
and uniformly mixing the conductive carbon, the binder and the dispersing solvent according to a certain proportion to obtain the conductive carbon slurry. Conductive carbon: adhesive: the mass ratio of the solvent is 1: (0.5-2): (5-20), and the viscosity of the prepared slurry is about 2000-6000 mPas.
The conductive carbon comprises high-conductivity carbon material powder such as acetylene black, super p, Ketjen black, graphene, carbon nano tube and the like, and can be used in combination with one or more of the carbon material powder in different proportions;
the binder comprises polyvinylidene fluoride (PVDF), cellulose (CMC) and other high polymer materials which have polymerization and crosslinking reaction capacities and can form a film;
the dispersion solvent includes N-methylpyrrolidone (NMP), deionized water, and the like having a dissolving and dispersing ability for the binder.
Step 2, preparing a carbon coating film: and coating the conductive carbon slurry on the surface of the S/C positive plate of the lithium-sulfur battery, and drying in the atmosphere or protective atmosphere environment to obtain the conductive carbon coating positive plate with the carbon coating film. The slurry coating equipment can adopt existing industrial equipment such as roller coating, spraying and the like.
The protective atmosphere is negative pressure (10-4000 Pa), nitrogen and other atmospheres, the drying temperature interval of the carbon coating film is 60-90 ℃, the drying time is 0.3-1 h, and the film thickness of the carbon coating film is 5-30 μm.
Step 3, heat treatment of the electrode slice with the gradient structure: and carrying out heat treatment on the conductive carbon coating layer positive plate in the atmosphere or protective atmosphere environment, and regulating and controlling the sublimation and desublimation processes of active sulfur in the S/C positive plate material to obtain the lithium sulfur battery positive plate-gradient structure positive plate with the sulfur carrying capacity sequentially reduced from the S/C positive plate to the carbon coating layer along the thickness section.
The heat treatment temperature is 100-120 ℃, and the heat treatment time is 0.3-2 h. The protective atmosphere refers to negative pressure (10-4000 Pa), nitrogen and other atmospheres and is used for regulating and controlling the sublimation-desublimation process of active sulfur of the S/C positive electrode material in the positive electrode plate.
In order to make the objects, technical solutions, contents and advantages of the present invention clearer, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.
Example 1
(1) The positive plate provided by enterprises is directly adopted.
(2) Acetylene black, PVDF and NMP were mixed in a mass ratio of 1: 0.5: and 5, uniformly mixing for 4 hours to obtain conductive carbon slurry, wherein the viscosity of the slurry is about 6000mPa & s.
(3) Coating the conductive carbon slurry on the surface of an existing S/C positive plate (the thickness of an S/C positive plate film is about 15 mu m, the loading mass of active sulfur is about 60-70%) of the lithium-sulfur battery by using roller coating equipment at room temperature, wherein the coating thickness is about 30 mu m, drying is carried out at a temperature interval of 60 ℃ for 0.5h, and then the conductive carbon coating positive plate with the carbon coating film is obtained, and the thickness of the dried carbon coating film is about 10 mu m.
(4) Putting the conductive carbon coating positive plate at N2And carrying out heat treatment at 110 ℃ for 1h under the protective atmosphere and normal pressure environment to obtain the positive plate with the gradient structure. As shown in the scanning electron microscope of fig. 2 and its elemental spectrum analysis, the light-colored dots, the bulk regions, represent the active sulfur material. After the active sulfur in the S/C material of the positive plate is subjected to heat treatment, an obvious gradient distribution structure is formed along the cross section through sublimation-desublimation phase change and diffusion adsorption, and meanwhile, reserved pores are formed in the original S/C material due to sublimation of the active sulfur. Through surface area statistical analysis, the volume fraction of active sulfur in the carbon coating film is about 35-0% in a gradient way, and the volume fraction of active sulfur in the sulfur/carbon positive pole piece is about 55-65%.
The impedance EIS curve of the button half cell is shown in FIG. 4, and the electrode transfer resistance RctAbout 45 omega compared to no carbon coatingThe reference sample, the impedance decreased by about 57%; the change of the discharge specific capacity of the variable rate is shown in fig. 5, the specific capacity of the 1C rate is about 850mAh/g, and compared with a reference sample without a carbon coating layer, the performance is improved by about 70%.
Example 2
(1) The method comprises the following steps of mixing S/C anode powder (wherein the mass ratio of active sulfur is 60%) provided by an enterprise, Ketjen black and PVDF according to the mass ratio of 90: 5: and 5, uniformly mixing and stirring for 8 hours, and using NMP as a solvent (the mass ratio of S/C positive electrode powder to NMP is about 1: 3) to prepare the positive electrode material coating slurry with the viscosity of about 3000mPa & S. An S/C anode coating is prepared by coating on an aluminum foil with the thickness of 25um by adopting a spraying method, and the thickness of the S/C anode film is about 13 mu m after drying for 1h at the temperature of 90 ℃ in a temperature interval, as shown in figure 3.
(2) Conductive carbon black Super P: CMC: deionized water according to the mass ratio of 1: 1: 8, uniformly mixing for 8 hours to obtain the conductive carbon slurry, and further regulating the viscosity of the conductive carbon slurry to be about 5000mPa & s by adopting deionized water.
(3) And (3) coating the conductive carbon slurry synthesized in the step (2) on the surface of the positive plate in the step (1) by adopting a roll coating method at room temperature, drying for 0.5h at the temperature range of 90 ℃ in the atmosphere and normal pressure environment, and then carrying out two-stage heat treatment at 100 ℃ for 2h to obtain the positive plate with the gradient structure.
As shown in the SEM and elementary spectrum of FIG. 3, the carbon coating was about 10 μm thick, with the light-colored dot areas representing the active sulfur material. After the sulfur in the S/C material of the positive plate is subjected to heat treatment, an obvious gradient distribution structure is formed along the cross section through sublimation-desublimation phase change and diffusion adsorption, and meanwhile, a reserved pore is formed in the original S/C material due to sublimation of active sulfur. Through surface area statistical analysis, the volume fraction of active sulfur in the carbon coating film is about 30-3% in a gradient way, and the volume fraction of active sulfur in the sulfur/carbon positive pole piece is about 50-55%.
The impedance EIS curve of the button half cell is shown in FIG. 4, and the electrode transfer resistance RctAbout 50 Ω, a decrease of about 52% in impedance compared to the reference sample without the carbon coating; the change of the specific discharge capacity of the coating with variable rate is shown in figure 5, the specific capacity of 1C rate is about 850mAh/g, compared with the carbon-free coatingThe performance is improved by about 70% over the sample.
Example 3
(1) The positive plate directly uses porous carbon as a sulfur/carbon positive electrode material.
(2) Acetylene black, PVDF and NMP were mixed in a mass ratio of 1: 2: 20, and uniformly mixing for 4 hours to obtain conductive carbon slurry, wherein the viscosity of the slurry is about 3000mPa & s.
(3) Coating the conductive carbon slurry on the surface of an existing S/C positive plate (the thickness of an S/C positive plate film is about 35 mu m, the loading mass of active sulfur is about 55-65%) of the lithium-sulfur battery by using roller coating equipment at room temperature, wherein the coating thickness is about 30 mu m, drying is carried out at a temperature interval of 90 ℃ for 0.5h to obtain the conductive carbon coating positive plate with the carbon coating film, and the thickness of the dried carbon coating film is about 30 mu m.
(4) Putting the conductive carbon coating positive plate at N2And carrying out heat treatment at 100 ℃ for 2 hours under the protective atmosphere and normal pressure environment to obtain the positive plate with the gradient structure.
Example 4
(1) The carbon nano tube is directly used as the anode plate made of the sulfur/carbon anode material.
(2) Acetylene black, PVDF and NMP were mixed in a mass ratio of 1: 1.5: 20, and uniformly mixing for 4 hours to obtain the conductive carbon slurry, wherein the viscosity of the slurry is about 2000 mPas.
(3) Coating the conductive carbon slurry on the surface of an existing S/C positive plate (the thickness of the S/C positive plate is about 15 mu m, the loading mass of active sulfur is about 60-65%) of the lithium-sulfur battery by using roller coating equipment at room temperature, wherein the coating thickness is about 30 mu m, drying is carried out at the temperature of 60 ℃ for 1h to obtain the conductive carbon coating positive plate with the carbon coating film, and the thickness of the dried carbon coating film is about 5 mu m.
(4) Putting the conductive carbon coating positive plate at N2And carrying out heat treatment at 120 ℃ for 0.3h under the protective atmosphere and normal pressure environment to obtain the positive plate with the gradient structure.
The invention develops a universal conductive carbon coating technology, which is coated and tightly combined on the surface of the existing S/C positive plate, and inhibits the loss of polysulfide lithium in the electrochemical reaction process by improving the holding and adsorption proportion of electrolyte on the positive plate side, thereby effectively improving the high-rate electrochemical performance of the lithium-sulfur battery; meanwhile, by the sulfur sublimation-desublimation regulation and control technology (namely, under a certain temperature, the sulfur sublimation speed is constant, the sublimation amount is increased along with time and is approximately linearly related, and the sublimation amount needs to be determined according to experimental conditions and a specific experiment of a preset value of the preset volume), the S/C positive plate forms a certain preset volume space, the damage of volume expansion of an active sulfur intermediate product to a positive electrode structure in the electrochemical reaction process is relieved, and the electrochemical properties such as the stability of the circulating capacity of the lithium-sulfur battery can be effectively improved. Has important significance for the industrialization and the commercialization of the high-performance lithium-sulfur battery.

Claims (6)

1. A preparation method of a high-performance lithium-sulfur battery positive plate with a gradient structure is characterized in that conductive carbon is used as a conductive agent, a high-molecular polymer is used as a binder, and an organic solvent or deionized water is used as a solvent to synthesize conductive carbon slurry; then coating the conductive carbon slurry on the surface of the sulfur/carbon positive plate, and drying to obtain a uniform carbon coating film; and then regulating and controlling the sulfur sublimation and desublimation processes of the S/C layer of the positive plate by heat treatment of the sulfur/carbon positive plate with the carbon coating layer to prepare the lithium-sulfur battery positive plate with the gradient structure, wherein the sulfur carrying amount from the positive plate to the carbon coating layer is reduced sequentially.
2. The preparation method of the high-performance lithium sulfur battery positive plate with the gradient structure according to claim 1 is characterized by comprising the following specific operation steps:
step 1, preparing conductive carbon slurry:
mixing conductive carbon, a binder and a solvent according to a mass ratio of 1: (0.5-2): (5-20) uniformly mixing to obtain conductive carbon slurry with the viscosity of 2000-6000 mPa & s;
step 2, preparing a carbon coating film:
coating the conductive carbon slurry on the surface of the sulfur/carbon positive plate, and drying in the atmosphere or protective atmosphere environment to obtain a conductive carbon coating layer positive plate with a carbon coating layer film;
step 3, heat treatment of the electrode slice with the gradient structure:
and (3) carrying out heat treatment on the conductive carbon coating layer positive plate in the atmosphere or protective atmosphere environment to obtain the lithium-sulfur battery positive plate with the sulfur carrying amount sequentially reduced from the positive plate to the carbon coating layer film, namely the positive plate with the gradient structure.
3. The method for preparing the positive plate of the lithium-sulfur battery with the gradient structure and the high performance according to claim 2, is characterized in that the method for preparing the positive plate of the sulfur/carbon battery is as follows: preparing coating slurry by taking a sulfur/carbon anode material as a main body, and preparing the anode sheet on an aluminum foil or a copper foil by spraying and roller coating methods; the sulfur/carbon anode material is obtained by dissolving or depositing an active sulfur material on a conductive carrier, wherein the conductive carrier is porous carbon, graphene, a carbon nano tube, expanded graphite, acetylene black or Ketjen black carbon material.
4. The method for preparing the positive plate of the lithium-sulfur battery with the gradient structure and high performance according to claim 2, wherein the step 1 specifically comprises the following steps: the conductive carbon comprises one or a combination of several of acetylene black, super p, Ketjen black, graphene and carbon nanotubes; the binder comprises polyvinylidene fluoride (PVDF), cellulose (CMC) and a high polymer material of CMC-Na; the solvent comprises N-methylpyrrolidone (NMP) and deionized water.
5. The method for preparing the positive plate of the lithium-sulfur battery with the gradient structure and the high performance according to claim 2, wherein the drying temperature range in the step 2 is 60-90 ℃, and the film thickness of the carbon coating film after being fully dried is 5-30 μm.
6. The method for preparing the positive plate of the lithium-sulfur battery with the gradient structure and the high performance according to claim 2, wherein the heat treatment temperature in the step 3 is 100-120 ℃, and the heat treatment time is 0.3-2 h; the protective atmosphere refers to negative pressure and nitrogen atmosphere.
CN202111093108.6A 2021-09-17 2021-09-17 Preparation method of high-performance lithium-sulfur battery positive plate with gradient structure Pending CN113764624A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114597411A (en) * 2022-03-02 2022-06-07 陕西科技大学 Acetylene black flexible sulfur fixation material, preparation method thereof, sulfur fixation method and lithium-sulfur battery positive electrode

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102163720A (en) * 2011-02-12 2011-08-24 中南大学 Lithium sulfide-porpous carbon compound positive material for lithium ion battery and preparation method thereof
CN104362294A (en) * 2014-12-05 2015-02-18 上海空间电源研究所 Porous sulfur anode used for lithium-sulfur battery and preparation method thereof as well as lithium-sulfur battery
CN104600251A (en) * 2014-12-26 2015-05-06 中南大学 Lithium-sulfur battery positive electrode and preparation method thereof
JP2015115119A (en) * 2013-12-09 2015-06-22 株式会社アルバック Method of forming positive electrode for lithium sulfur secondary battery and positive electrode for lithium sulfur secondary battery
CN104752682A (en) * 2015-03-16 2015-07-01 山东玉皇新能源科技有限公司 Preparation method of sulphur/carbon composite cathode material for lithium sulphur battery
WO2016107564A1 (en) * 2014-12-29 2016-07-07 中国地质大学（武汉） Composite positive material for lithium-sulphur battery with high rate performance and preparation method
US20160240840A1 (en) * 2015-02-18 2016-08-18 Hui He Alkali metal-sulfur secondary battery containing a pre-sulfurized cathode and production process
CN106207088A (en) * 2016-09-30 2016-12-07 上海空间电源研究所 A kind of lithium-sulphur cell positive electrode and preparation method thereof
CN106384828A (en) * 2016-10-19 2017-02-08 天津力神电池股份有限公司 Crosslinking porous composite lithium-sulfur battery anode and preparation method thereof
CN106410116A (en) * 2016-10-19 2017-02-15 天津力神电池股份有限公司 Graded porous composite lithium-sulfur battery cathode and preparation method thereof
CN112072067A (en) * 2020-09-18 2020-12-11 北京理工大学 Carbon-sulfur composite positive electrode for lithium-sulfur battery and preparation method thereof

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102163720A (en) * 2011-02-12 2011-08-24 中南大学 Lithium sulfide-porpous carbon compound positive material for lithium ion battery and preparation method thereof
JP2015115119A (en) * 2013-12-09 2015-06-22 株式会社アルバック Method of forming positive electrode for lithium sulfur secondary battery and positive electrode for lithium sulfur secondary battery
CN104362294A (en) * 2014-12-05 2015-02-18 上海空间电源研究所 Porous sulfur anode used for lithium-sulfur battery and preparation method thereof as well as lithium-sulfur battery
CN104600251A (en) * 2014-12-26 2015-05-06 中南大学 Lithium-sulfur battery positive electrode and preparation method thereof
WO2016107564A1 (en) * 2014-12-29 2016-07-07 中国地质大学（武汉） Composite positive material for lithium-sulphur battery with high rate performance and preparation method
US20160240840A1 (en) * 2015-02-18 2016-08-18 Hui He Alkali metal-sulfur secondary battery containing a pre-sulfurized cathode and production process
CN104752682A (en) * 2015-03-16 2015-07-01 山东玉皇新能源科技有限公司 Preparation method of sulphur/carbon composite cathode material for lithium sulphur battery
CN106207088A (en) * 2016-09-30 2016-12-07 上海空间电源研究所 A kind of lithium-sulphur cell positive electrode and preparation method thereof
CN106384828A (en) * 2016-10-19 2017-02-08 天津力神电池股份有限公司 Crosslinking porous composite lithium-sulfur battery anode and preparation method thereof
CN106410116A (en) * 2016-10-19 2017-02-15 天津力神电池股份有限公司 Graded porous composite lithium-sulfur battery cathode and preparation method thereof
CN112072067A (en) * 2020-09-18 2020-12-11 北京理工大学 Carbon-sulfur composite positive electrode for lithium-sulfur battery and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
王杰等: "多壁碳纳米管夹层抑制锂硫电池穿梭效应", 《化工进展》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114597411A (en) * 2022-03-02 2022-06-07 陕西科技大学 Acetylene black flexible sulfur fixation material, preparation method thereof, sulfur fixation method and lithium-sulfur battery positive electrode
CN114597411B (en) * 2022-03-02 2023-03-14 陕西科技大学 Acetylene black flexible sulfur fixation material, preparation method thereof, sulfur fixation method and lithium-sulfur battery positive electrode

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Application publication date: 20211207