CN111063867B - Metal thio compound @ S composite material, preparation thereof and application thereof in lithium-sulfur battery - Google Patents
Metal thio compound @ S composite material, preparation thereof and application thereof in lithium-sulfur battery Download PDFInfo
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Abstract
The invention relates to a metal thio compound @ S composite material, a preparation method thereof and application thereof in a lithium-sulfur battery, which are characterized by comprising a core and a coating material for coating the core; the material of the core is elemental sulfur; the coating material is at least one metal thio compound with a structural formula shown on the right;
Description
Technical Field
The invention relates to a preparation method and application of a lithium-sulfur battery positive electrode material, and belongs to the field of lithium-sulfur secondary batteries.
Background
With the development of society, on one hand, the performance requirements of the public on portable electronic products are continuously improved; on the other hand, people have increased environmental awareness and knowledge of non-renewable resources, so that energy storage power stations, electric vehicles and smart power grids of various scales begin to develop rapidly. The two reasons are that the requirements on the energy density and the power density of the lithium ion battery are higher and higher, but the lithium ion battery system with the best comprehensive performance at present is difficult to meet the requirements on high specific energy in the future society due to the limitation of the theoretical lithium storage capacity of the battery system and the electrode material.
Lithium-sulfur batteries are the most promising alternatives to lithium-ion batteries because their theoretical energy density (2500Wh/kg) is much higher than the energy density of existing lithium ions (200 Wh/kg). However, during the lithiation/delithiation process of the Li-S battery, polysulfide which is an intermediate product of the sulfur positive electrode reaction is dissolved in the ether electrolyte and migrates out from the positive electrode, and then disproportionation reaction is carried out on the negative electrode or other parts of the battery to form insoluble Li2S or Li2S2Li deposited on the negative electrode or other non-conducting region2S or Li2S2It loses activity, resulting in continuous loss of active material and degradation of battery capacity.
In order to solve the problem of lithium polysulfide shuttling of lithium-sulfur batteries, the most common strategy is to use a nano-structured carbon material with a high specific surface area to adsorb sulfur in pores of the carbon material, and prevent polysulfide shuttling by physical adsorption and restriction. For example, patent CN201410256653 discloses a nitrogen-doped graphene-coated nano sulfur positive electrode composite material, and nano sulfur particles are uniformly coated by nitrogen-doped graphene sheet layers, so that the dissolution and shuttle effects of polysulfides in a lithium sulfur battery are effectively inhibited, and the cycle stability of the battery is improved. In patent CN102208645A, amorphous carbon is coated on the surface of the sulfur-based cathode active material, the particles of the cathode material are 10 nm-10 μm, and the thickness of the amorphous carbon layer is 1-5 nm, which significantly improves the conductivity of the cathode material. The carbon material coating has a certain effect on inhibiting polysulfide shuttling, but with repeated dissolution and deposition of sulfur in the charging and discharging processes, sulfur active substances gradually migrate from the interior of the carbon to the surface, so that the carbon material loses the effect. In order to achieve better reduction of polysulfide dissolution, a thicker carbon material coating is often required, and although better conductivity is ensured, lithium ion transport is significantly inhibited. In addition, some researchers coat the surface of sulfur particles with an organic conductive polymer or metal nitrogen and sulfide with polarity, for example, patent CN102447113A proposes a lithium battery using a polymer-coated sulfur/carbon composite material as an anode, the composite material is dispersed in a solution, a polymer monomer is added, then an oxidant is added under the protection of inert gas at a low temperature to initiate polymerization, centrifugation, washing and drying are performed to obtain a polymer-coated elemental sulfur/carbon composite material, CN201711394697 coats molybdenum disulfide on the outer layer of a sulfur-containing hollow microsphere, the polar molybdenum disulfide can effectively adsorb polysulfide molecules which are also polar, the dissolution of the polysulfide molecules in an electrolyte is inhibited to a certain extent, the utilization rate of elemental sulfur is improved, and the shuttle effect is inhibited.
Disclosure of Invention
In order to solve the technical defects that the lithium conducting performance of the existing lithium-sulfur battery coated positive electrode material is poor and the electrical performance is not ideal, the invention provides a metal thio compound @ S composite material (the invention is also called as the composite material for short) and aims to improve the lithium conducting and electron conducting performance of the sulfur coated material and improve the electrical performance of the positive electrode active material of the lithium-sulfur battery.
The second purpose of the invention is to provide a preparation method of the composite material.
The third purpose of the invention is to provide the application of the composite material in a lithium-sulfur battery.
The fourth purpose of the invention is to provide a lithium-sulfur battery positive electrode containing the composite material.
A fifth object of the present invention is to provide a lithium-sulfur battery equipped with the positive electrode.
A metal thio compound @ S composite comprising a core and a cladding material cladding the core; the material of the core is elemental sulfur; the coating material is at least one metal thio compound with a structural formula of formula 1;
r is a hydrocarbon group, a tertiary amino group or an ether group; m is a metal element; preferably Li, Na, K, Zn, Cu, Cd, Ca, Bi, Pb, Ni, Sn, Fe, Co or Ag, and n is the valence of M.
The invention innovatively provides a metal thio compound @ S composite material, and the thickness of a coating layer can be reduced by adopting the metal thio compound with the structural formula as a coating material. The coating material has good lithium ion transmission capability, ensures the lithium ion transmission under the condition of tight coating, and can provide certain electronic conductivity; in addition, the coating has good elasticity, and the cracking and falling of the coating layer caused by volume change in the charge and discharge process of elemental sulfur can be relieved. Moreover, the structural formula of the coating material can provide certain capacity, and the electrical performance of the composite material can be synergistically improved through multiple functions.
The compounds of formula 1 can also be described as
It was found that-CSS-and the bound M-metal in the clad material are critical to give the composite material good electrical performance. In addition, the selection of the group of R is helpful for further synergistically improving the electrical properties of the composite material.
In R, the hydrocarbyl is preferably C1-C6 alkyl, C2-C6 alkenyl or alkynyl or C6-C12 aryl.
The structural formula of the tertiary amino is R1R2N-, in which R1、R2Independently C1-C6 alkyl.
SaidThe structural formula of the ether group is R3O-, in which R3Is C1-C6 alkyl or C6-C12 aryl.
Researches show that the electrical property of the composite material with the R as the tertiary amino group is better; further, when R is selected to be a smaller substituent, the electrical properties can be further improved.
Further preferably, the metallothio compound has the structural formula 1-A.
Preferably, the mass percentage of the sulfur elementary substance in the positive electrode material is 60-90%.
Preferably, the particle diameter of the core (elemental sulfur particles) is 1nm to 150 um.
Preferably, the thickness of the coating material is 1nm to 5 μm.
The invention also provides a preparation method of the metal thio compound @ S composite material, which is characterized by comprising the following steps of: comprises the following preparation steps of the preparation method,
step (1): carrying out complex reaction on an aqueous solution containing elemental sulfur, a water-soluble thio compound with a structural formula of formula 2 and a surfactant;
step (2): adding M metal salt into the complex reaction liquid obtained in the step (1) for reaction to prepare the metal thio compound @ S composite material;
M1is H, Na, K or NH4。
More preferably, the water-soluble thio compound is one or more of dimethyldithiocarbamate, sodium dimethyldithiocarbamate, potassium dimethyldithiocarbamate and ammonium dimethyldithiocarbamate.
Preferably, the molar ratio of the sulfur simple substance to the water-soluble thio compound is (1-5): 1.
The concentration of the water-soluble thio compound in the initial water solution of the complexation reaction is 0.01-1 mol/L.
The surfactant is used for improving the wetting effect between elemental sulfur particles and a water-soluble thio compound, and is beneficial to forming a uniform and compact coating layer so as to improve the electrical property.
The surfactant is at least one of cationic surfactant, anionic surfactant and nonionic surfactant.
Preferably, the surfactant is a surfactant having a complexing action.
More preferably, the surfactant is one or more of 3-sulfopropyl hexadecyl dimethyl ammonium, polyethylene glycol, sodium dodecyl benzene sulfonate, sodium lauryl sulfate and N-polyvinylpyrrolidone.
Preferably, the concentration of the surfactant in the initial aqueous solution of the complexation reaction is 0.01-0.5 mol/L.
In the invention, the water-soluble thio compound, the surfactant and the elemental sulfur are mixed, and are subjected to hydrothermal complex reaction after being subjected to ultrasonic dispersion in an aqueous solution to be dissolved to form a solution or sol.
Preferably, the temperature in the complexation reaction is 40-90 ℃. The reaction time is 2-24 h. The reaction pH is 3-13.
And (2) adding M metal salt into the solution or sol obtained in the step (1) to obtain the composite material.
The M metal salt is preferably a water-soluble salt of M metal.
Preferably, the cation of the M metal salt is one or more metal ions selected from Li, Zn, Cu, Cd, Ca, Bi, Pb, Ni, Sn, Fe, Co and Ag; the anion being Cl-、SO4 2-、NO3 -、CH3COO-One or more than two of them.
The M metal salt is preferably added to the solution or sol of step (1) in the form of an aqueous solution.
Preferably, the solute concentration in the M metal salt-containing solution is 0.01 to 1mol/L, preferably 0.05 to 0.1 mol/L.
In the step (2), after the reaction is finished, carrying out solid-liquid separation, washing and drying the obtained solid to obtain the metal thio compound @ S composite material;
the washing process comprises a water washing process and an organic solvent washing process which are carried out in advance; the organic solvent is absolute ethyl alcohol or carbon tetrachloride.
The invention relates to a preferable preparation method, which comprises the following specific steps:
step (1): mixing a sulfur simple substance, a water-soluble thio compound and a surfactant, ultrasonically dispersing in a water solution, transferring to a reaction kettle, and dissolving by utilizing a hydrothermal complexation reaction to form a solution or a sol; the water-soluble thio compound is water-soluble dimethyl dithiocarbamate or dimethyl dithiocarbamate, and is preferably one or more of dimethyl dithiocarbamate, sodium dimethyl dithiocarbamate, potassium dimethyl dithiocarbamate and ammonium dimethyl dithiocarbamate;
the time of ultrasonic dispersion is preferably 0.5-3 h;
the temperature of the hydrothermal complexation reaction is 40-90 ℃, the reaction time is 2-24h, and the reaction pH is 3-13.
Step (2): slowly adding a solution containing one or more than two metal ions of Li, Zn, Cu, Cd, Ca, Bi, Pb, Ni, Sn, Fe, Co or Ag, naturally cooling after the reaction is completed, centrifuging, alternately washing a solid product by deionized water and an organic solvent, and drying to obtain the sulfur cathode material coated by the organic metal thio-compound.
The organic solvent used in the washing process is absolute ethyl alcohol or carbon tetrachloride.
The invention also provides an application of the metal thio compound @ S composite material, and the metal thio compound @ S composite material is used as a positive active material of a lithium-sulfur battery.
Preferably, the metal thio compound @ S composite material, the conductive agent and the binder are mixed to prepare the positive electrode material of the lithium-sulfur battery. The conductive agent and binder may be any materials known to those skilled in the art.
In the positive electrode material, the mass ratio of the metal thio compound @ S composite material, the conductive agent and the binder can be reasonably adjusted according to the use requirement.
Preferably, the lithium-sulfur battery positive electrode material is slurried by a solvent, coated on a positive electrode current collector and dried to obtain the lithium-sulfur battery positive electrode.
Still more preferably, the lithium sulfur battery positive electrode and the lithium negative electrode, the separator and the electrolyte are assembled into a lithium sulfur battery.
The invention also provides a lithium-sulfur battery anode, which comprises an anode current collector and an anode material compounded on the surface of the anode current collector; the positive electrode material comprises a conductive agent, a binder and the metal thio compound @ S composite material.
The invention also provides a lithium-sulfur battery, which comprises a positive electrode, a negative electrode, a diaphragm for separating the positive electrode and the negative electrode, and electrolyte for soaking the positive electrode and the negative electrode; the positive electrode is the positive electrode for a lithium-sulfur battery according to claim 9.
In the lithium-sulfur battery, the negative electrode, the diaphragm and the electrolyte can be materials which are well known to a person skilled in the lithium-sulfur battery industry.
Preferably, the negative electrode is a metallic lithium or lithium boron alloy negative electrode.
The electrolyte includes a solvent, a lithium salt, and an additive. The solvent is one or a mixture of more of DOL, DME, PEGDME, DMSO, MiPS, EMS, TMS, FEC, EC and DMC; the lithium salt is LiTFSI, LiFSI, LiDFOB, LiDFBOP, LiBOB, LiBETI or LiPF6、LiBF4、LiAsF6、LiClO4One or more of the above; the additive is LiNO3、NH4TFSI、LiI、AlI3、P2S5VC, EDOT, chloridized-1, 3-dimethyl imidazole ionic liquid, dibenzothiazyl disulfide, iodonitrobenzene and triphenyl phosphine.
The technical scheme of the invention has the following beneficial effects:
1) the organic metal thio compound has good lithium ion transmission capability, ensures the lithium ion transmission under the condition of tight cladding, and can provide certain electronic conductivity;
2) compared with the existing inorganic coating layer, the coating layer provided by the invention has elasticity, and can relieve the cracking and falling off of the coating layer caused by volume change in the charge and discharge process of elemental sulfur.
3) The organometallic thio compound itself may provide some capacity.
4) The coating of the organic metal thio compound on the surface of the elemental sulfur can be realized in a mild chemical environment, and the method is simple and easy to implement and low in cost.
Drawings
Fig. 1 is a battery cycle stability performance diagram of the cathode material prepared in example 1;
fig. 2 is a battery cycle stability performance diagram of the cathode material prepared in example 2;
fig. 3 is a battery cycle stability performance diagram of the cathode material prepared in comparative example 1;
Detailed Description
The following examples are intended to illustrate the invention in further detail; and the scope of the claims of the present invention is not limited by the examples.
In the following examples and comparative examples, the particles of elemental S are 1-50 μm.
Example 1
Preparing a positive electrode material: 1.6g of simple substance S, 3.58g of dimethyl ammonium dimethyldithiocarbamate and 0.348g of sodium dodecyl benzene sulfonate are weighed and placed in 100mL of deionized water for ultrasonic dispersion for 1 h. And transferring the mixture into a water bath kettle after the ultrasonic treatment, setting the heating temperature to be 70 ℃, slowly dropwise adding the prepared 0.05mol/L silver nitrate solution, reacting for 12 hours, and naturally cooling. And placing the reacted solution in a centrifugal tube for centrifugation, adjusting the rotating speed to 8000r/min, alternately washing filter residues obtained by centrifugation with deionized water and ethanol for three times, and drying at 60 ℃ for 24 hours to obtain the cathode material.
Lithium sulfur battery assembly and testing: elemental sulfur, acetylene black and PVDF coated with organometallic thio compoundPreparing slurry according to the ratio of 6:3:1, coating the slurry on a carbon-coated aluminum foil to prepare a positive electrode, punching and cutting the prepared positive electrode into a circular electrode piece with the diameter of 13mm, and drying the circular electrode piece in a drying oven at the temperature of 55 ℃ for 1 hour. In argon atmosphere, a metal lithium sheet is taken as a negative electrode, a polypropylene microporous membrane with the model of Celgard 2400 is selected as a diaphragm, and 1.0M LiTFSI DOL electrolyte, namely DME, 1:1(V: V) +0.2M LiNO is selected as electrolyte3And assembling the button cell.
Example 2
Preparing a positive electrode material: 1.6g of simple substance S, 3.32g of sodium dimethyldithiocarbamate and 0.56g N-polyvinylpyrrolidone are weighed and placed in 80mL of deionized water for ultrasonic dispersion for 1 h. And transferring the mixture into a water bath kettle after the ultrasonic treatment, setting the heating temperature to be 70 ℃, slowly dropwise adding the prepared 0.05mol/L lithium acetate solution, reacting for 12 hours, and naturally cooling. And placing the reacted solution in a centrifugal tube for centrifugation, adjusting the rotating speed to 8000r/min, alternately washing filter residues obtained by centrifugation with deionized water and ethanol for three times, and drying at 60 ℃ for 24 hours to obtain the cathode material.
Lithium sulfur battery assembly and testing: preparing slurry by mixing an organic metal thio compound coated sulfur simple substance, acetylene black and PVDF according to the ratio of 6:3:1, coating the slurry on a carbon-coated aluminum foil to prepare a positive electrode, punching and cutting the prepared positive electrode into a circular electrode piece with phi 13mm, and drying the circular electrode piece in a drying oven at the temperature of 55 ℃ for 1 hour. In argon atmosphere, a metal lithium sheet is taken as a negative electrode, a polypropylene microporous membrane with the model of Celgard 2400 is selected as a diaphragm, and 1.0M LiTFSI DOL electrolyte, namely DME, 1:1(V: V) +0.2M LiNO is selected as electrolyte3And assembling the button cell.
Example 3
Preparing a positive electrode material: 1.6g of simple substance S, 3.32g of sodium dimethyldithiocarbamate and 0.56g of sodium dodecyl benzene sulfonate are weighed and placed in 80mL of deionized water for ultrasonic dispersion for 1 h. And transferring the mixture into a water bath kettle after the ultrasonic treatment, setting the heating temperature to be 70 ℃, slowly dropwise adding the prepared 0.02mol/L copper chloride solution, reacting for 12 hours, and naturally cooling. And placing the reacted solution in a centrifugal tube for centrifugation, adjusting the rotating speed to 8000r/min, alternately washing filter residues obtained by centrifugation with deionized water and ethanol for three times, and drying at 60 ℃ for 24 hours to obtain the cathode material.
Lithium sulfur battery assembly and testing: preparing slurry by mixing an organic metal thio compound coated sulfur simple substance, acetylene black and PVDF according to the ratio of 6:3:1, coating the slurry on a carbon-coated aluminum foil to prepare a positive electrode, punching and cutting the prepared positive electrode into a circular electrode piece with phi 13mm, and drying the circular electrode piece in a drying oven at the temperature of 55 ℃ for 1 hour. And (3) in an argon atmosphere, using a metal lithium sheet as a negative electrode, selecting a polypropylene microporous membrane of a Celgard 2400 model as a diaphragm, and assembling the button cell by using 1.0M LiTFSI DOL of electrolyte, namely DME (1: 1(V: V) +0.2M LiNO 3.
Example 4
Preparing a positive electrode material: 1.6g of elemental S and 1.88g of potassium butylxanthate (C) are weighed out5H9KOS2R is CH3CH2CH2CH2O-) and 0.56g of N-polyvinylpyrrolidone are placed in 80mL of deionized water for ultrasonic dispersion for 1 h. And transferring the mixture into a water bath kettle after the ultrasonic treatment, setting the heating temperature to be 70 ℃, slowly dropwise adding the prepared 0.05mol/L lithium acetate solution, reacting for 12 hours, and naturally cooling. And placing the reacted solution in a centrifugal tube for centrifugation, adjusting the rotating speed to 8000r/min, alternately washing filter residues obtained by centrifugation with deionized water and ethanol for three times, and drying at 60 ℃ for 24 hours to obtain the cathode material.
Lithium sulfur battery assembly and testing: preparing slurry by mixing an organic metal thio compound coated sulfur simple substance, acetylene black and PVDF according to the ratio of 6:3:1, coating the slurry on a carbon-coated aluminum foil to prepare a positive electrode, punching and cutting the prepared positive electrode into a circular electrode piece with phi 13mm, and drying the circular electrode piece in a drying oven at the temperature of 55 ℃ for 1 hour. In argon atmosphere, a metal lithium sheet is taken as a negative electrode, a polypropylene microporous membrane with the model of Celgard 2400 is selected as a diaphragm, and 1.0M LiTFSI DOL electrolyte, namely DME, 1:1(V: V) +0.2M LiNO is selected as electrolyte3And assembling the button cell.
Comparative example 1
Elemental sulfur powder, acetylene black, PVDF (polyvinylidene fluoride) are mixed according to the weight ratio of 6:3:1, coating the prepared slurry on a carbon-coated aluminum foil, and drying the carbon-coated aluminum foil in an oven at 80 ℃ for 8 hours until NMP is completely volatilized. And punching the dried sulfur pole piece into a round pole piece with the diameter of 13mm, and drying in an oven at the temperature of 55 ℃ for 1 hour. In argon atmosphere, a metal lithium sheet is taken as a negative electrode, a polypropylene microporous membrane with the model of Celgard 2400 is selected as a diaphragm, and 1.0M LiTFSI DOL electrolyte, namely DME, 1:1(V: V) +0.2M LiNO is selected as electrolyte3And assembling the button cell.
Comparative example 2
Preparing a positive electrode material: 3.32g of sodium dimethyldithiocarbamate and 0.56g of sodium dodecyl benzene sulfonate are placed in 80mL of deionized water for ultrasonic dispersion for 1 h. And transferring the mixture into a water bath kettle after the ultrasonic treatment, setting the heating temperature to be 70 ℃, slowly dropwise adding the prepared 0.02mol/L copper chloride solution, reacting for 12 hours, naturally cooling, adding 1.6g of elemental sulfur powder into the reaction precipitate obtained by centrifuging, filtering and drying, and ball-milling for 10 minutes to obtain the uniformly mixed anode material.
Lithium sulfur battery assembly and testing: the elemental sulfur, the acetylene black and the PVDF which are uniformly mixed with the organic metal thio compound are prepared into slurry according to the ratio of 6:3:1, the slurry is coated on a carbon-coated aluminum foil to prepare a positive electrode, the prepared positive electrode sheet is cut into a circular pole piece with phi of 13mm, and the circular pole piece is dried in a drying oven at the temperature of 55 ℃ for 1 hour. In argon atmosphere, a metal lithium sheet is taken as a negative electrode, a polypropylene microporous membrane with the model of Celgard 2400 is selected as a diaphragm, and 1.0M LiTFSI DOL electrolyte, namely DME, 1:1(V: V) +0.2M LiNO is selected as electrolyte3And assembling the button cell.
The battery prepared by various methods is subjected to charge-discharge cycle test on a blue charge-discharge tester under the test conditions of constant current 0.2C charge-discharge, a potential interval of 1.7-3.0V and 150 cycles, and the test results are shown in the following table.
Research shows that the electrical property of the composite material can be remarkably improved by coating the elemental sulfur with the coating material provided by the invention.
Claims (20)
1. A metal thio compound @ S composite comprising a core and a cladding material cladding the core; the material of the core is sulfur elementary substance; the coating material is at least one metal thio compound with a structural formula of formula 1;
r is alkyl, tertiary amino or ether group, M is metal element of Li, Na, K, Zn, Cu, Cd, Ca, Bi, Pb, Ni, Sn, Fe, Co or Ag, and n is the chemical valence value of M.
2. The metal thio compound @ S composite material as claimed in claim 1, wherein in R, the hydrocarbyl group is an alkyl group of C1-C6, an alkenyl or alkynyl group of C2-C6, or an aromatic group of C6-C12.
3. The metallothio compound @ S composite of claim 1, wherein the tertiary amino group has the formula R1R2N-, in which R1、R2Independently C1-C6 alkyl.
4. The metal thio compound @ S composite of claim 1, wherein the ether group has the formula R3O-, in which R3Is C1-C6 alkyl or C6-C12 aryl.
5. The metal thio compound @ S composite material of claim 1, wherein the elemental sulfur is present in the composite material in an amount of 60% to 90% by weight.
6. The metallothio compound @ S composite of claim 1, wherein the core has a particle size of from 1nm to 150 μm.
7. The metal thio compound @ S composite of claim 1, wherein the cladding material has a thickness of from 1nm to 5 μm.
8. A process for the preparation of the metal thio compound @ S composite material as claimed in any one of claims 1 to 7, characterized in that: comprises the following preparation steps of the preparation method,
step (1): carrying out complex reaction on an aqueous solution containing elemental sulfur, a water-soluble thio compound with a structural formula of formula 2 and a surfactant;
step (2): adding M metal salt into the complex reaction liquid obtained in the step (1) for reaction to prepare the metal thio compound @ S composite material;
M1is H, Na, K or NH4。
9. The method of claim 8, wherein: the water-soluble thio compound is one or more than two of dimethyl dithiocarbamate, sodium dimethyl dithiocarbamate, potassium dimethyl dithiocarbamate and ammonium dimethyl dithiocarbamate.
10. The method of claim 9, wherein: the molar ratio of the sulfur simple substance to the water-soluble thio compound is (1-5) to 1;
the concentration of the water-soluble thio compound in the initial water solution of the complexation reaction is 0.01-1 mol/L.
11. The method of claim 8, wherein: the surfactant is at least one of cationic surfactant, anionic surfactant and nonionic surfactant.
12. The method of claim 11, wherein: the surfactant is one or more than two of 3-sulfopropyl hexadecyl dimethyl ammonium, polyethylene glycol, sodium dodecyl benzene sulfonate, sodium lauryl sulfate and N-polyvinylpyrrolidone.
13. The method of claim 8, wherein: in the initial water solution of the complexation reaction, the concentration of the surfactant is 0.01-0.5 mol/L.
14. The method of claim 8, wherein: in the complex reaction, the temperature is 40-90 ℃, the reaction time is 2-24h, and the reaction pH is 3-13;
in the step (2), after the reaction is finished, carrying out solid-liquid separation, washing and drying the obtained solid to obtain the metal thio compound @ S composite material;
the washing process comprises a water washing process and an organic solvent washing process which are carried out in advance; the organic solvent is absolute ethyl alcohol or carbon tetrachloride.
15. Use of the metal thio compound @ S composite material as defined in any one of claims 1 to 7 or the metal thio compound @ S composite material as defined in any one of claims 8 to 14, wherein: it is used as a positive active material for a lithium-sulfur battery.
16. The use of claim 15, wherein: and mixing the metal thio compound @ S composite material, a conductive agent and a binder to prepare the lithium-sulfur battery positive electrode material.
17. The use of claim 16, wherein: and slurrying the lithium-sulfur battery positive electrode material with a solvent, coating the slurried material on a positive current collector, and drying to obtain the lithium-sulfur battery positive electrode.
18. The use of claim 17, wherein: and assembling the lithium-sulfur battery positive electrode, the lithium negative electrode, the diaphragm and the electrolyte into the lithium-sulfur battery.
19. The positive electrode of the lithium-sulfur battery comprises a positive electrode current collector and a positive electrode material compounded on the surface of the positive electrode current collector; the cathode material comprises a conductive agent, a binder and the metal thio compound @ S composite material as defined in any one of claims 1-7.
20. A lithium-sulfur battery comprises a positive electrode, a negative electrode, a diaphragm for separating the positive electrode and the negative electrode, and electrolyte for soaking the positive electrode and the negative electrode; wherein the positive electrode is the positive electrode for a lithium-sulfur battery according to claim 19;
the negative electrode is a metallic lithium or lithium boron alloy negative electrode; the electrolyte comprises a solvent, a lithium salt and an additive; the solvent is one or a mixture of more of DOL, DME, PEGDME, DMSO, MiPS, EMS, TMS, FEC, EC and DMC; the lithium salt is LiTFSI, LiFSI, LiDFOB, LiDFBOP, LiBOB, LiBETI or LiPF6、LiBF4、LiAsF6、LiClO4One or more of the above; the additive is LiNO3、NH4TFSI、LiI、AlI3、P2S5VC, EDOT, chloridized-1, 3-dimethyl imidazole ionic liquid, dibenzothiazyl disulfide, iodonitrobenzene and triphenyl phosphine.
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| CN104201339A (en) * | 2014-09-18 | 2014-12-10 | 厦门大学 | Battery positive-electrode as well as preparation method and application thereof in lithium-sulfur batteries |
| CN104600316A (en) * | 2015-01-07 | 2015-05-06 | 上海大学 | Sulfur/polymer/graphene ternary composite and preparation method thereof |
| CN104795544A (en) * | 2015-04-10 | 2015-07-22 | 北京理工大学 | Lithium-sulfur battery positive pole material and preparation method thereof |
| CN106953092A (en) * | 2017-04-14 | 2017-07-14 | 哈尔滨工业大学 | A kind of preparation method of positive material for lithium-sulfur battery |
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| CN104201339A (en) * | 2014-09-18 | 2014-12-10 | 厦门大学 | Battery positive-electrode as well as preparation method and application thereof in lithium-sulfur batteries |
| CN104600316A (en) * | 2015-01-07 | 2015-05-06 | 上海大学 | Sulfur/polymer/graphene ternary composite and preparation method thereof |
| CN104795544A (en) * | 2015-04-10 | 2015-07-22 | 北京理工大学 | Lithium-sulfur battery positive pole material and preparation method thereof |
| CN106953092A (en) * | 2017-04-14 | 2017-07-14 | 哈尔滨工业大学 | A kind of preparation method of positive material for lithium-sulfur battery |
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