CN114725614A - Diaphragm coating material of lithium-sulfur battery and preparation method thereof - Google Patents

Diaphragm coating material of lithium-sulfur battery and preparation method thereof Download PDF

Info

Publication number
CN114725614A
CN114725614A CN202210455107.XA CN202210455107A CN114725614A CN 114725614 A CN114725614 A CN 114725614A CN 202210455107 A CN202210455107 A CN 202210455107A CN 114725614 A CN114725614 A CN 114725614A
Authority
CN
China
Prior art keywords
lithium
sulfur battery
polysulfide
diaphragm
inorganic salt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210455107.XA
Other languages
Chinese (zh)
Inventor
王天奕
唐发琳
陈鹏
王赪胤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yangzhou University
Original Assignee
Yangzhou University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yangzhou University filed Critical Yangzhou University
Priority to CN202210455107.XA priority Critical patent/CN114725614A/en
Publication of CN114725614A publication Critical patent/CN114725614A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a design of a diaphragm coating material of a lithium-sulfur battery and a preparation method thereof. The material is synthesized by a hydrothermal method from a plurality of sub-materials with different functions, wherein the sub-materials comprise a trapping layer with high specific surface area for blocking polysulfide from passing through a membrane, an adsorbent for limiting polysulfide emission and a catalyst for accelerating polysulfide conversion. According to the invention, the adsorbent and the catalyst are grown on the capturing layer through a hydrothermal reaction and coated on the diaphragm, so that the capturing layer is used for capturing free polysulfide firstly, then the polysulfide is fixed by the adsorbent, and the polysulfide is catalytically converted by the catalyst during reaction, thereby effectively inhibiting the shuttle effect of the polysulfide and improving the performance of the battery.

Description

Diaphragm coating material of lithium-sulfur battery and preparation method thereof
Technical Field
The invention belongs to the technical field of lithium-sulfur batteries, and particularly relates to a diaphragm coating material of a lithium-sulfur battery and a preparation method thereof.
Background
The lithium-sulfur battery has higher theoretical specific capacity (1675 mAh g)-1) Meanwhile, the sulfur resource is rich, the cost is low, and the commercialization of the sulfur-containing material is facilitated. However, lithium-sulfur batteries also faceThere are various problems, such as (1) poor conductivity of charging and discharging products, sulfur and lithium sulfide, which are unfavorable for capacity release; (2) the intermediate polysulfide (Li 2Sn, 4. ltoreq. n.ltoreq.8) of the charge and discharge has a high solubility in ether electrolytes, so that it is produced from the sulfur side and dissolved in the electrolyte, driven by the electric field and the concentration gradient across the membrane, then passes through the membrane to the lithium side and is converted into Li2S and Li2S2 for permanent deposition. (3) During charging and discharging of the battery, the conversion of sulfur relates to the conversion of solid-liquid solid phase. I.e., both sulfur and lithium sulfide are poorly soluble in the electrolyte and thus are solid-phase, while polysulfide is readily soluble in the electrolyte, i.e., liquid-phase. The energy barrier for the conversion from liquid phase to solid phase is high, so that the conversion is difficult and the reaction kinetics is slow.
Conventional lithium sulfur batteries employ a commercial polyacrylonitrile membrane having a large number of pores on its surface to facilitate ion transport. But also allows polysulfides to pass through the pores to the metal side and be converted to permanent deposits of lithium sulfide, resulting in loss of sulfur.
Therefore, there is a need to find a relatively simple and efficient method for inhibiting the shuttling of polysulfides and accelerating the conversion of polysulfides to improve the performance of lithium sulfur batteries and promote their commercialization.
Disclosure of Invention
The invention aims to provide a diaphragm coating material of a lithium-sulfur battery and a preparation method thereof, and aims to solve the problems of slow shuttle and conversion of polysulfide in the conventional lithium-sulfur battery.
The technical scheme for realizing the purpose of the invention is as follows: a diaphragm coating material of a lithium-sulfur battery and a preparation method thereof comprise the following steps:
step 1, stirring a trapping layer material with a high specific surface area in a solvent to uniformly disperse the trapping layer material;
step 2, adding metal inorganic salt required for preparing the adsorbent and metal inorganic salt required for preparing the catalyst into the solution obtained in the step 1, and uniformly stirring;
and step 3: adding the auxiliary agent into the solution obtained in the step 2, and uniformly stirring;
and 4, step 4: carrying out hydrothermal reaction on the solution obtained in the step 3, and then cleaning, centrifuging and drying;
and 5: introducing gas into the solid obtained in the step 4 in a tubular furnace to perform high-temperature reaction;
step 6: and (3) mixing the solid obtained in the step (5) with an adhesive, adding an organic solvent to prepare slurry, coating the slurry on a lithium-sulfur battery diaphragm, and finally drying to obtain the diaphragm coating material of the lithium-sulfur battery.
Preferably, the solvent is one or more of deionized water, methanol, ethanol and the like, preferably deionized water, and the solvent accounts for 85% of the total volume of the reaction kettle for the hydrothermal reaction.
Preferably, the trapping layer material with high specific surface area can be, but is not limited to, any one of graphene, carbon nitride, carbon nanotube, and hollow carbon sphere.
Preferably, the metal inorganic salt required for preparing the adsorbent is an inorganic salt of divalent or trivalent iron ions; the metal inorganic salt required for preparing the catalyst can be any one of metal inorganic salts of cobalt, nickel, molybdenum, tungsten and the like, and divalent or trivalent cobalt metal inorganic salts are preferred.
Preferably, the adjuvant is one or more of glucose, urea, melamine and thiourea, and thiourea is preferred.
Preferably, in the obtained separator coating material for the lithium-sulfur battery, the mass ratio of the capture layer material to the adsorbent material to the catalyst material is 3: 4: 3.
preferably, in the step 4, the hydrothermal reaction temperature is 180 ℃ and the hydrothermal reaction time is 24 hours.
Preferably, before the hydrothermal reaction, an auxiliary agent ammonium fluoride is additionally added into the solution obtained in the step 3, and the mixture is stirred uniformly.
Preferably, in step 5, the gas introduced into the tube furnace is an inert gas, and the high-temperature reaction temperature is 550 to 650 ℃.
Preferably, in step 6, the binder is polyvinylidene fluoride, and the organic solvent is N-methylpyrrolidone.
Compared with the prior art, the invention provides a diaphragm coating material of a lithium-sulfur battery and a preparation method thereof. A material having a high specific surface area, an adsorbent material having a strong adsorption force to polysulfides, and a catalyst material accelerating the conversion of polysulfides are combined and coated on the separator. The method realizes capture-adsorption-catalysis of free polysulfide in the electrolyte in the charging and discharging processes of the lithium-sulfur battery, fundamentally inhibits shuttle of polysulfide and improves the battery capacity.
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
Drawings
Fig. 1 is a schematic structural diagram of a separator coating material design for a lithium sulfur battery.
Fig. 2 is an X-ray diffraction pattern of the graphene composite iron hepta-sulfur octa/cobalt disulfide heterojunction referred to in this example 5.
Fig. 3 is a scanning electron microscope image of the graphene composite iron heptasulfide octasulfide/cobalt disulfide heterojunction related to this embodiment 5.
Fig. 4 is a high-power transmission electron microscope image of the graphene composite iron heptasulfide octasulfide/cobalt disulfide heterojunction related to the embodiment 5.
Fig. 5 is a schematic lattice diagram of the graphene composite iron-heptasulfide-octasulfide/cobalt disulfide heterojunction related to this example 5.
FIG. 6 shows a graph of the lithium-sulfur battery using graphene composite iron hepta-sulfur octa/cobalt disulfide heterojunction modified membrane and a comparison graph of 1A g in example 5-1Long cycle performance plot at current density.
FIG. 7 shows the results of 1A g of the lithium sulfur battery using the heterojunction modified separator according to examples 1 to 5-1Long cycle performance plot at current density of (a).
Description of reference numerals:
1-trapping layer material, 2-adsorbent material, 3-catalyst material, 11-redox graphene sheets (rGO), 21-iron heptasulfur eight (Fe 7S 8), 31-cobalt disulfide (CoS 2), 101-nitrogen doped redox graphene composite iron heptasulfur eight/cobalt disulfide heterojunction (CoS 2/Fe7S 8/NG) modified membrane cell performance data, 102-nitrogen doped redox graphene composite cobalt disulfide (CoS 2/NG) modified membrane cell performance data, 103-nitrogen doped redox graphene composite iron heptasulfur eight modified membrane cell performance data (Fe 7S 8/NG), 104-nitrogen doped redox graphene modified membrane cell performance data (NG), 105-conventional membrane lithium sulfur cell performance data.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Generally, a lithium sulfur battery is composed of a sulfur positive electrode, a separator, a lithium negative electrode, an electrolyte, and a current collector. The charge-discharge principle is the conversion of sulfur to polysulfide to lithium sulfide.
A diaphragm: the electrolyte is positioned between the anode and the cathode, plays a role in blocking electron transmission and conducting ions, and needs certain electrolyte wettability. In general, a polypropylene (PP) separator is used as a separator of a lithium sulfur battery.
A trapping layer: during the charging and discharging processes of the lithium-sulfur battery, a large amount of polysulfide dissolved in the electrolyte exists in the electrolyte on the whole sulfur positive electrode side, and the polysulfide penetrates through the diaphragm to the lithium metal side under the action of an electric field and a concentration gradient. It is therefore necessary to establish a "net" on the side of the membrane facing the sulfur anode to capture polysulfides so that they pass through the membrane more difficultly. Therefore, a material with a large specific surface area is required to act as a mesh, wherein graphene, carbon nitride and the like have a large specific surface area due to a two-dimensional lamellar structure, and a large number of folds exist on the lamellar structure, so that adsorption sites for polysulfide can be increased, and difficulty in dissipation of the polysulfide can be increased.
Adsorbent: polysulfide is a polar material, but conventional carbon materials are difficult to adsorb polysulfide, and researches show that iron compounds have a strong adsorption effect on polysulfide and can effectively limit shuttling of polysulfide. However, iron-based compounds are mostly formed into nanoparticles, and it is difficult to adsorb free polysulfides on the whole surface.
Catalyst: the principle of charging and discharging of the lithium-sulfur battery is as follows: the back and forth conversion of sulfur to polysulfide to lithium sulfide involves the conversion of solid-liquid to solid phase, wherein the liquid phase is changed to solid phase, and the product is sulfur or lithium sulfide with poor conductivity, so the reaction is slow and the conversion is incomplete. Therefore, cobalt, nickel, molybdenum, tungsten and other metal compounds are needed to perform catalytic conversion on the catalyst, so as to accelerate the reaction process. But relatively ineffective in adsorbing polysulfides and thus not in time to adsorb and convert them.
Auxiliary agents: some auxiliary reagents in material synthesis, such as nitrogen doping, melamine and urea are adopted, and thiourea is added for generating metal sulfide.
Auxiliary agent: in the hydrothermal process, the material is made to grow towards the reagents required for a particular situation.
Heterojunction: a special composite material structure is prepared from two or more materials through compounding and growing to obtain two characteristics and special effect. It is worth mentioning that the final composition is not a single substance, nor is it a simple mechanical mixture of the two raw materials.
According to the invention, the diaphragm is modified, so that polysulfide dissociated in the electrolyte is firmly bound in the diaphragm modification layer, and the polysulfide is subjected to catalytic conversion by the catalyst (3) in the charge-discharge process, so that the capacity of the lithium-sulfur battery is fully released.
Referring to fig. 1, fig. 1 shows that sorbent material 2 and catalyst material 3 are grown on the surface of trapping layer material 1.
The design of the invention can bring the following advantages:
(a) the specific surface area of the trapping layer material 1 is large, so that the adsorbent material 2 and the catalyst material 3 can be effectively and uniformly distributed on the trapping layer material, more adsorption and catalysis sites are exposed, and trapping-adsorption-catalysis of polysulfide is facilitated;
(b) the adsorbent material 2 and the catalyst material 3 are grown on the capture layer material 1 in a hydrothermal process, which can better adhere to the capture layer material and bring more defect sites to the capture layer material 1 than conventional mixing, so that it can better adsorb and catalyze polysulfides;
(c) the adsorbent material 2 and the catalyst material 3 grow on the capture layer simultaneously in the hydrothermal process, and the growth process is accompanied with the change of valence, so that the adsorbent material 2 and the catalyst material 3 can form a heterojunction more easily, the catalytic capability of the adsorbent material 2 is improved, and the adsorption effect of the catalyst material 3 is improved.
(d) The heterojunction formed by the adsorbent material 2 and the catalyst material 3 can form a special interface at the interface of the two materials, so that the adsorption and catalysis effects are further improved.
Example 1
The invention relates to a preparation method of a diaphragm coating material of a lithium-sulfur battery, which comprises the following steps:
step 1: uniformly stirring 60mg of graphene oxide in 60ml of deionized water;
and 2, step: adding 117mg of ferric chloride hexahydrate and 48mg of cobalt nitrate hexahydrate into 10ml of deionized water, ultrasonically stirring uniformly, and then pouring into the graphene oxide solution obtained in the step 1;
and step 3: adding 1008mg of urea into 15ml of deionized water, uniformly stirring by ultrasonic waves, and then pouring into the solution obtained in the step 2;
and 4, step 4: the mixed solution obtained in step 3 was poured into a new 100ml reaction vessel and heated under water at 180 ℃ for 24 hours.
And 5: after the hydrothermal process is finished, washing and centrifuging the material for many times, and freeze-drying the material;
step 6: freeze drying the materialPutting the mixture into a tube furnace, introducing nitrogen atmosphere, raising the temperature to 600 ℃ at a speed of 4 ℃/min, and preserving the temperature for 2 hours to obtain a final product, namely a nitrogen-doped redox graphene composite ferroferric oxide/cobaltosic oxide heterojunction (Co)3O4/Fe3O4/NG）。
And 7: mixing the obtained Co3O4/Fe3O4The mass ratio of/NG to the adhesive polyvinylidene fluoride is 9: 1, mixing, then pouring N-methyl pyrrolidone solvent, and uniformly mixing to form slurry.
And 8: and (4) coating the slurry obtained in the step (7) on a polypropylene diaphragm for the lithium-sulfur battery by using a scraper, and then drying in vacuum.
And step 9: the obtained pole piece is cut into a circular shape with the diameter of 19, and then the lithium-sulfur battery is assembled, wherein the modified side of the diaphragm is the side facing the sulfur positive electrode.
In this embodiment, nitrogen-doped graphene (NG) serves to capture free polysulfides, while Fe3O4Acting to adsorb and anchor free polysulphides, Co3O4Can effectively catalyze polysulfide to improve the performance of the lithium-sulfur battery.
Example 2
The invention relates to a preparation method of a diaphragm coating material of a lithium-sulfur battery, which comprises the following steps:
step 1: uniformly stirring 60mg of graphene oxide in 60ml of deionized water;
step 2: adding 117mg of ferric chloride hexahydrate and 48mg of cobalt nitrate hexahydrate into 10ml of deionized water, stirring uniformly by ultrasonic waves, and pouring into the solution obtained in the step (1);
and step 3: adding 1008mg of urea into 15ml of deionized water, uniformly stirring by ultrasonic waves, and then pouring into the solution obtained in the step 2;
and 4, step 4: the mixed solution obtained in step 3 was poured into a new 100ml reaction vessel and heated under water at 180 ℃ for 24 hours.
And 5: after the hydrothermal process is finished, washing and centrifuging the material for many times, and freeze-drying the material;
step 6: putting the freeze-dried material into a tube furnace, and introducingRaising the temperature to 600 ℃ at a speed of 4 ℃/min in an ammonia atmosphere, and preserving the temperature for 2 hours to obtain a final product, namely the nitrogen-doped redox graphene composite iron nitride/cobalt nitride heterojunction (CoN/Fe)2N/NG）。
And 7: the obtained CoN/Fe2The mass ratio of N/NG to adhesive polyvinylidene fluoride is 9: 1, mixing, then pouring N-methyl pyrrolidone solvent, and uniformly mixing to form slurry.
And 8: and (4) coating the slurry obtained in the step (7) on a polypropylene diaphragm for the lithium-sulfur battery by using a scraper, and then drying in vacuum.
And step 9: the obtained pole piece is cut into a circular shape with the diameter of 19, and then the lithium-sulfur battery is assembled, wherein the modified side of the diaphragm is the side facing the sulfur positive electrode.
In this embodiment, nitrogen-doped graphene (NG) serves to capture free polysulfides, while Fe2N plays a role in adsorbing and anchoring free polysulfide, and CoN can effectively catalyze polysulfide to improve the performance of the lithium-sulfur battery.
Example 3
The invention relates to a preparation method of a diaphragm coating material of a lithium-sulfur battery, which comprises the following steps:
step 1: uniformly stirring 60mg of carbon nitride in 60ml of deionized water;
step 2: adding 117mg of ferric chloride hexahydrate and 48mg of cobalt nitrate hexahydrate into 10ml of deionized water, stirring uniformly by ultrasonic waves, and pouring into the solution obtained in the step (1);
and step 3: adding 608mg of thiourea into 15ml of deionized water, stirring uniformly by ultrasonic, and pouring into the solution obtained in the step 2;
and 4, step 4: the mixed solution obtained in step 3 was poured into a new 100ml reaction vessel and heated under water at 180 ℃ for 24 hours.
And 5: after the hydrothermal process is finished, washing and centrifuging the material for many times, and freeze-drying the material;
step 6: putting the freeze-dried material into a tube furnace, introducing nitrogen atmosphere, raising the temperature to 550 ℃ at a speed of 4 ℃/min, and preserving the heat for 2 hours to obtain a final product, namely the carbon nitride composite iron heptasulfide octasulfide/cobalt disulfide heterojunction (CoS)2/Fe7S8/C3N4）。
And 7: the obtained CoS2/Fe7S8/C3N4And adhesive polyvinylidene fluoride according to the mass ratio of 9: 1, mixing, then pouring N-methyl pyrrolidone solvent, and uniformly mixing to form slurry.
And step 8: and (4) coating the slurry obtained in the step (7) on a polypropylene diaphragm for the lithium-sulfur battery by using a scraper, and then drying in vacuum.
And step 9: the obtained pole piece is cut into a circular shape with the diameter of 19, and then the lithium-sulfur battery is assembled, wherein the modified side of the diaphragm is the side facing the sulfur positive electrode.
In this embodiment, carbon nitride acts to trap free polysulfides, while Fe7S8Acts to adsorb and anchor free polysulfides, CoS2Can effectively catalyze polysulfide to improve the performance of the lithium-sulfur battery.
Example 4
The invention relates to a preparation method of a diaphragm coating material of a lithium-sulfur battery, which comprises the following steps:
step 1: uniformly stirring 60mg of graphene oxide in 60ml of deionized water;
and 2, step: adding 117mg of ferric chloride hexahydrate and 48mg of cobalt nitrate hexahydrate into 10ml of deionized water, uniformly stirring by ultrasonic waves, and pouring into the solution obtained in the step (1);
and step 3: adding 608mg of thiourea into 15ml of deionized water, uniformly stirring by ultrasonic waves, and pouring into the solution obtained in the step 2;
and 4, step 4: the mixed solution obtained in step 3 was poured into a new 100ml reaction vessel and heated under water at 180 ℃ for 24 hours.
And 5: after the hydrothermal process is finished, washing and centrifuging the material for many times, and freeze-drying the material;
and 6: putting the freeze-dried material into a tube furnace, introducing nitrogen atmosphere, raising the temperature to 600 ℃ at a rate of 4 ℃/min, and preserving the heat for 2 hours to obtain a final product, namely a nitrogen-doped redox graphene composite iron hepta-sulfur octa-cobalt disulfide heterojunction (CoS)2/Fe7S8/NG）。
And 7: the obtained CoS2/Fe7S8The mass ratio of the/NG to the adhesive polyvinylidene fluoride is 9: 1, mixing, then pouring N-methyl pyrrolidone solvent, and uniformly mixing to form slurry.
And 8: and (4) coating the slurry obtained in the step (7) on a polypropylene diaphragm for the lithium-sulfur battery by using a scraper, and then drying in vacuum.
And step 9: the obtained pole piece is cut into a circular shape with the diameter of 19, and then the lithium-sulfur battery is assembled, wherein the modified side of the diaphragm is the side facing the sulfur positive electrode.
In this embodiment, nitrogen-doped graphene (NG) serves to capture free polysulfides, while Fe7S8Acts to adsorb and anchor free polysulfides, CoS2Can effectively catalyze polysulfide to improve the performance of the lithium-sulfur battery.
Example 5
The invention relates to a preparation method of a diaphragm coating material of a lithium-sulfur battery, which comprises the following steps:
step 1: uniformly stirring 60mg of graphene oxide in 60ml of deionized water;
step 2: adding 117mg of ferric chloride hexahydrate and 48mg of cobalt nitrate hexahydrate into 10ml of deionized water, uniformly stirring by ultrasonic waves, and pouring into the solution obtained in the step (1);
and step 3: adding 608mg of thiourea and 10mg of ammonium fluoride into 15ml of deionized water, uniformly stirring by ultrasonic waves, and pouring into the solution obtained in the step 2;
and 4, step 4: the mixed solution obtained in step 3 was poured into a new 100ml reaction vessel and heated under water at 180 ℃ for 24 hours.
And 5: after the hydrothermal process is finished, washing and centrifuging the material for many times, and freeze-drying the material;
step 6: putting the freeze-dried material into a tube furnace, introducing nitrogen atmosphere, raising the temperature to 600 ℃ at a rate of 4 ℃/min, and preserving the heat for 2 hours to obtain a final product, namely the nitrogen-doped redox graphene composite iron heptasulfide octasulfide/cobalt disulfide heterojunction (CoS)2/Fe7S8/NG）；
And 7: the obtained CoS2/Fe7S8The mass ratio of the/NG to the adhesive polyvinylidene fluoride is 9: 1, then pouring N-methyl pyrrolidone solvent, and uniformly mixing to form slurry.
And 8: and (4) coating the slurry obtained in the step (7) on a polypropylene diaphragm for the lithium-sulfur battery by using a scraper, and then drying in vacuum.
And step 9: the obtained pole piece is cut into a circular shape with the diameter of 19, and then the lithium-sulfur battery is assembled, wherein the modified side of the diaphragm is the side facing the sulfur positive electrode.
In this embodiment, nitrogen-doped graphene (NG) serves to capture free polysulfides, while Fe7S8Acts to adsorb and anchor free polysulfides, CoS2Can effectively catalyze polysulfide to improve the performance of the lithium-sulfur battery.
Comparative example 1
The comparative example is Fe prepared by the same method without adding cobalt nitrate in step 27S8/NG。
Comparative example 2
This comparative example is CoS prepared by the same method without adding ferric chloride in step 22/NG。
Comparative example 3
The comparative example is NG prepared in the same manner without adding cobalt nitrate and ferric chloride in step 2.
FIGS. 2 to 5 show CoS prepared in example 52/Fe7S8Structural characterization of/NG, respectively as follows:
referring to FIG. 2, FIG. 2 illustrates the synthesis of CoS by characterization of the material's crystal lattice using X-rays2/Fe7S8/NG。
Referring to FIG. 3, FIG. 3 is derived by scanning Electron microscopy, CoS2/Fe7S8the/NG nano-particles grow on the graphene sheet layers, the particles are small, and a large number of folds exist on the redox graphene sheet layers.
Referring to FIG. 4, FIG. 4 shows CoS by high power transmission electron microscopy2/Fe7S8the/NG nano-particles grow onOn the graphene sheet layer, the particles are small, and a large number of folds exist on the redox graphene sheet layer.
Referring to fig. 5, fig. 5 shows that there are many different crystal lattices on one particle by high power transmission electron microscopy, and 21 is measured to be the corresponding crystal lattice of Fe7S8, 31 is the corresponding crystal lattice of CoS2, and 11 is measured to be the crystal lattice of graphene oxide. The lattices are staggered with each other, and the material can be obtained to form a heterojunction of CoS2/Fe7S 8.
Referring to FIG. 6, FIG. 6 shows that at a current density of 1 Ag-1:
101-based on CoS2/Fe7S8The specific capacity and the cycling stability of the lithium-sulfur battery with/NG modified diaphragm are the best, and the lithium-sulfur battery benefits from the capture of free polysulfide, Fe, by NG7S8Adsorption of polysulfides, CoS2The catalytic effect on polysulfide conversion and the synergistic effect of the three components lead to the effect that 1+1+1 is more than 3;
102-CoS prepared based on comparative example 22The cycle stability of the lithium-sulfur battery with the/NG modified diaphragm is poor due to the lack of sufficient adsorption capacity;
103-Fe prepared based on comparative example 17S8The lithium-sulfur battery with the/NG modified diaphragm has low capacity and poor stability due to lack of sufficient catalytic capability;
104-the lithium sulfur battery based on the NG modified separator prepared in comparative example 3, had a low capacity in the early stage but a good stability but a very rapid decay in the later stage due to lack of sufficient adsorption and catalytic capabilities;
105-lithium sulfur cells with conventional separators (Celgard 2500 separator) without the aid of trapping layers, adsorbents and catalysts, resulting in lower capacity and less stability.
Referring to FIG. 7, FIG. 7 shows that at a current density of 1 Ag-1: compare the performance profiles of examples 1-4 and example 5. It can be seen that Co is contained in the embodiments 1 to 43O4/Fe3O4/NG、CoN/Fe2N/NG、CoS2/Fe7S8/C3N4、CoS2/Fe7S8After the/NG modified diaphragm, the performance of the battery is better than that of the unmodified diaphragm. However, the battery performance in the embodiment 5 is superior to the embodiments 1 to 4.

Claims (10)

1. A preparation method of a diaphragm coating material of a lithium-sulfur battery is characterized by comprising the following steps:
step 1, stirring a trapping layer material with a high specific surface area in a solvent to uniformly disperse the trapping layer material;
step 2, adding metal inorganic salt required for preparing the adsorbent and metal inorganic salt required for preparing the catalyst into the solution obtained in the step 1, and uniformly stirring;
and step 3: adding the auxiliary agent into the solution obtained in the step 2 and stirring uniformly;
and 4, step 4: carrying out hydrothermal reaction on the solution obtained in the step 3, then cleaning, centrifuging and drying;
and 5: introducing gas into the solid obtained in the step 4 in a tubular furnace to perform high-temperature reaction;
step 6: and (3) mixing the solid obtained in the step (5) with an adhesive, adding an organic solvent to prepare slurry, coating the slurry on a lithium-sulfur battery diaphragm, and drying to obtain the diaphragm coating material of the lithium-sulfur battery.
2. The method of claim 1, wherein the solvent is one or more of deionized water, methanol and ethanol, preferably deionized water, and the solvent accounts for 85% of the total volume of the reaction kettle for the hydrothermal reaction.
3. The method of claim 1, wherein the trapping layer with high specific surface area is any one of graphene, carbon nitride, carbon nanotube, and hollow carbon sphere.
4. The method of claim 1, wherein the inorganic salt of a metal required for the preparation of the adsorbent is an inorganic salt of a divalent or trivalent iron ion; the metal inorganic salt required for preparing the catalyst can be any one of cobalt, nickel, molybdenum and tungsten metal inorganic salt, and divalent or trivalent cobalt metal inorganic salt is preferred.
5. The method according to claim 1, wherein the adjuvant is one or more of glucose, urea, melamine, thiourea, preferably thiourea.
6. The method according to claim 1, wherein in the step 4, the hydrothermal reaction temperature is 180 ℃ and the hydrothermal reaction time is 24 h.
7. The method of claim 1, wherein the adjuvant and the auxiliary agent ammonium fluoride are added to the solution obtained in step 2 and stirred uniformly.
8. The method according to claim 1, wherein in the step 5, the gas introduced into the tube furnace is inert gas, and the high-temperature reaction temperature is 550-650 ℃.
9. The method of claim 1, wherein in step 6, the binder is polyvinylidene fluoride and the organic solvent is N-methylpyrrolidone.
10. The method according to claim 1, wherein the mass ratio of the trapping layer material, the adsorbent material and the catalyst material in the membrane coating material of the lithium-sulfur battery is 3: 4: 3.
CN202210455107.XA 2022-04-24 2022-04-24 Diaphragm coating material of lithium-sulfur battery and preparation method thereof Pending CN114725614A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210455107.XA CN114725614A (en) 2022-04-24 2022-04-24 Diaphragm coating material of lithium-sulfur battery and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210455107.XA CN114725614A (en) 2022-04-24 2022-04-24 Diaphragm coating material of lithium-sulfur battery and preparation method thereof

Publications (1)

Publication Number Publication Date
CN114725614A true CN114725614A (en) 2022-07-08

Family

ID=82246568

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210455107.XA Pending CN114725614A (en) 2022-04-24 2022-04-24 Diaphragm coating material of lithium-sulfur battery and preparation method thereof

Country Status (1)

Country Link
CN (1) CN114725614A (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106848161A (en) * 2017-01-05 2017-06-13 清华大学深圳研究生院 Lithium-sulfur cell barrier film and the lithium-sulfur cell comprising the barrier film
CN108091868A (en) * 2017-12-29 2018-05-29 东南大学 A kind of multidimensional composite high-performance lithium ion battery negative material and preparation method thereof
CN109755442A (en) * 2019-02-28 2019-05-14 大连理工大学 A kind of preparation method of network-like carbon load iron base compound material and its application on lithium-sulfur cell
CN109904369A (en) * 2019-01-30 2019-06-18 天津大学 Heterojunction nano material diaphragm for lithium-sulfur battery and preparation method thereof
CN111068726A (en) * 2019-11-26 2020-04-28 浙江大学 Preparation method of iron-doped nickel phosphide composite nitrogen-doped reduced graphene oxide electrocatalytic material
CN111211273A (en) * 2020-01-13 2020-05-29 吉林大学 Lithium-sulfur battery with iron nitride nanoparticles growing in situ on reduced graphene oxide as modified diaphragm material and preparation method thereof
CN112531281A (en) * 2020-09-25 2021-03-19 山东大学 Preparation method of modified diaphragm for lithium-sulfur battery based on nano metal hydroxide-carbon composite material

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106848161A (en) * 2017-01-05 2017-06-13 清华大学深圳研究生院 Lithium-sulfur cell barrier film and the lithium-sulfur cell comprising the barrier film
CN108091868A (en) * 2017-12-29 2018-05-29 东南大学 A kind of multidimensional composite high-performance lithium ion battery negative material and preparation method thereof
CN109904369A (en) * 2019-01-30 2019-06-18 天津大学 Heterojunction nano material diaphragm for lithium-sulfur battery and preparation method thereof
CN109755442A (en) * 2019-02-28 2019-05-14 大连理工大学 A kind of preparation method of network-like carbon load iron base compound material and its application on lithium-sulfur cell
CN111068726A (en) * 2019-11-26 2020-04-28 浙江大学 Preparation method of iron-doped nickel phosphide composite nitrogen-doped reduced graphene oxide electrocatalytic material
CN111211273A (en) * 2020-01-13 2020-05-29 吉林大学 Lithium-sulfur battery with iron nitride nanoparticles growing in situ on reduced graphene oxide as modified diaphragm material and preparation method thereof
CN112531281A (en) * 2020-09-25 2021-03-19 山东大学 Preparation method of modified diaphragm for lithium-sulfur battery based on nano metal hydroxide-carbon composite material

Similar Documents

Publication Publication Date Title
Shen et al. Metal-organic frameworks (MOFs) and their derivative as electrode materials for lithium-ion batteries
CN109873158B (en) Carbon material for lithium-sulfur battery and preparation and application thereof
CN112688021B (en) Preparation method and application of metal organic framework MOF-808 film-based functional interlayer material
CN110323425B (en) Hollow flaky zinc oxide/cobaltosic oxide heterojunction, electrode, lithium ion battery and preparation method thereof
CN112421045B (en) Preparation method and application of graphene-loaded high-conductivity molybdenum sulfide nanoflower material
CN111864156A (en) Preparation method of metal nitride-metal oxide heterojunction modified diaphragm for lithium-sulfur battery and lithium-sulfur battery comprising diaphragm
CN111463414A (en) Interlayer material and preparation method and application thereof
Ye et al. MOF-related electrocatalysts for sulfur reduction/evolution reactions: Composition modulation, structure design, and mechanism research
CN113178659B (en) Modified diaphragm, preparation method thereof and lithium-sulfur battery
CN110492065B (en) S/Co/CNF composite material based on waste cigarette ends and preparation method and application thereof
CN114639819B (en) Sodium-rich manganese-based oxide composite substrate metal oxide self-supporting binary anode material and preparation method thereof
CN114725614A (en) Diaphragm coating material of lithium-sulfur battery and preparation method thereof
CN114864939A (en) Lithium-sulfur battery anode catalytic material and preparation method and application thereof
CN114069159A (en) Membrane based on nitrogen-enriched column layer structure MOF and preparation method and application thereof
Li et al. Efficient immobilization and bidirectional catalysis of polysulfide conversion by FeCoP quantum dots for lithium–sulfur batteries
CN114464807A (en) Oxygen-deficient metal oxide catalyst, in-situ preparation method thereof and lithium-sulfur battery
CN111293293A (en) Molybdenum disulfide nanotube/sulfur composite cathode material with increased interlayer spacing and preparation method and application thereof
CN115513468B (en) Preparation method of CNTs/OMC ordered microporous carbon nanospheres and application method of CNTs/OMC ordered microporous carbon nanospheres in lithium-sulfur battery
CN114149028B (en) Method for doping molybdenum disulfide with oxygen induced by ethylene glycol and application of method in lithium-sulfur battery
CN114204214B (en) Functionalized modified diaphragm and preparation method and application thereof
CN114976484B (en) Loaded with Ni 2 P-Co Schottky junction active site echinoid carbon material electrocatalyst, preparation method and application thereof
CN114229823B (en) Preparation of cobalt-nickel catalyzed melamine foam synthesized porous carbon and application of porous carbon in lithium-sulfur battery
CN114368788B (en) Composite material and battery composite diaphragm
CN114853085B (en) Preparation method of cobalt vanadium sulfide and application of cobalt vanadium sulfide as negative electrode material of sodium ion battery
CN117117192A (en) Carbon-supported CeO 2 Co heterojunction active site electrocatalyst, preparation method and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination