CN113937418B - Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery - Google Patents
Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery Download PDFInfo
- Publication number
- CN113937418B CN113937418B CN202111180708.6A CN202111180708A CN113937418B CN 113937418 B CN113937418 B CN 113937418B CN 202111180708 A CN202111180708 A CN 202111180708A CN 113937418 B CN113937418 B CN 113937418B
- Authority
- CN
- China
- Prior art keywords
- solvent
- lithium
- carbon
- carbon fiber
- sulfur battery
- 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.)
- Active
Links
- JDZCKJOXGCMJGS-UHFFFAOYSA-N [Li].[S] Chemical compound [Li].[S] JDZCKJOXGCMJGS-UHFFFAOYSA-N 0.000 title claims abstract description 91
- 238000002360 preparation method Methods 0.000 title claims abstract description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 73
- 229920000049 Carbon (fiber) Polymers 0.000 claims abstract description 72
- 239000004917 carbon fiber Substances 0.000 claims abstract description 72
- 229910021393 carbon nanotube Inorganic materials 0.000 claims abstract description 70
- 239000002041 carbon nanotube Substances 0.000 claims abstract description 70
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 67
- 238000000034 method Methods 0.000 claims abstract description 54
- 238000010438 heat treatment Methods 0.000 claims abstract description 46
- 239000002131 composite material Substances 0.000 claims abstract description 36
- 239000011248 coating agent Substances 0.000 claims abstract description 23
- 238000000576 coating method Methods 0.000 claims abstract description 23
- 239000000758 substrate Substances 0.000 claims abstract description 23
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 98
- 239000002904 solvent Substances 0.000 claims description 49
- USIUVYZYUHIAEV-UHFFFAOYSA-N diphenyl ether Chemical compound C=1C=CC=CC=1OC1=CC=CC=C1 USIUVYZYUHIAEV-UHFFFAOYSA-N 0.000 claims description 40
- 238000001035 drying Methods 0.000 claims description 37
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 31
- 239000002105 nanoparticle Substances 0.000 claims description 28
- 239000007788 liquid Substances 0.000 claims description 21
- CCCMONHAUSKTEQ-UHFFFAOYSA-N octadecene Natural products CCCCCCCCCCCCCCCCC=C CCCMONHAUSKTEQ-UHFFFAOYSA-N 0.000 claims description 21
- 239000012046 mixed solvent Substances 0.000 claims description 20
- 239000011259 mixed solution Substances 0.000 claims description 19
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 18
- 150000001875 compounds Chemical class 0.000 claims description 18
- 238000002156 mixing Methods 0.000 claims description 18
- HOIQWTMREPWSJY-GNOQXXQHSA-K iron(3+);(z)-octadec-9-enoate Chemical compound [Fe+3].CCCCCCCC\C=C/CCCCCCCC([O-])=O.CCCCCCCC\C=C/CCCCCCCC([O-])=O.CCCCCCCC\C=C/CCCCCCCC([O-])=O HOIQWTMREPWSJY-GNOQXXQHSA-K 0.000 claims description 17
- 239000006255 coating slurry Substances 0.000 claims description 14
- 239000012153 distilled water Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 239000002033 PVDF binder Substances 0.000 claims description 10
- -1 polypropylene Polymers 0.000 claims description 10
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 10
- 238000005406 washing Methods 0.000 claims description 10
- BCKXLBQYZLBQEK-KVVVOXFISA-M Sodium oleate Chemical compound [Na+].CCCCCCCC\C=C/CCCCCCCC([O-])=O BCKXLBQYZLBQEK-KVVVOXFISA-M 0.000 claims description 9
- 238000009835 boiling Methods 0.000 claims description 9
- 239000006258 conductive agent Substances 0.000 claims description 9
- 239000011230 binding agent Substances 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 238000010992 reflux Methods 0.000 claims description 8
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 claims description 7
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 claims description 7
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 claims description 7
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 claims description 7
- 239000005642 Oleic acid Substances 0.000 claims description 7
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 claims description 7
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 claims description 7
- HFDVRLIODXPAHB-UHFFFAOYSA-N 1-tetradecene Chemical compound CCCCCCCCCCCCC=C HFDVRLIODXPAHB-UHFFFAOYSA-N 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 6
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 5
- 239000004743 Polypropylene Substances 0.000 claims description 5
- 239000003054 catalyst Substances 0.000 claims description 5
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 5
- XTAZYLNFDRKIHJ-UHFFFAOYSA-N n,n-dioctyloctan-1-amine Chemical compound CCCCCCCCN(CCCCCCCC)CCCCCCCC XTAZYLNFDRKIHJ-UHFFFAOYSA-N 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 229940095068 tetradecene Drugs 0.000 claims description 3
- 229920001021 polysulfide Polymers 0.000 abstract description 24
- 239000005077 polysulfide Substances 0.000 abstract description 24
- 150000008117 polysulfides Polymers 0.000 abstract description 24
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 20
- 229910052744 lithium Inorganic materials 0.000 abstract description 20
- 238000006243 chemical reaction Methods 0.000 abstract description 6
- 238000005580 one pot reaction Methods 0.000 abstract description 5
- 239000010410 layer Substances 0.000 description 17
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 16
- 230000000694 effects Effects 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 239000011593 sulfur Substances 0.000 description 13
- 229910052717 sulfur Inorganic materials 0.000 description 13
- 230000001351 cycling effect Effects 0.000 description 10
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 239000011159 matrix material Substances 0.000 description 5
- 239000007774 positive electrode material Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 239000011267 electrode slurry Substances 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- 239000012300 argon atmosphere Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000011229 interlayer Substances 0.000 description 3
- 229910001416 lithium ion Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- 238000000498 ball milling Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 2
- 239000011807 nanoball Substances 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000002346 layers by function Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
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
- H01M50/409—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
- 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
- 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
- H01M50/44—Fibrous 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
-
- 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
- H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing 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
- H01M50/454—Separators, membranes or diaphragms characterised by the material having a layered structure comprising a non-fibrous layer and a fibrous layer superimposed on one another
-
- 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)
- Cell Separators (AREA)
Abstract
The invention provides a lithium-sulfur battery diaphragm, a preparation method thereof and a lithium-sulfur battery, wherein the lithium-sulfur battery diaphragm comprises a diaphragm substrate and a diaphragm coating arranged on the surface of the diaphragm substrate, and the diaphragm coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite. The lithium sulfur battery diaphragm is prepared by a one-pot method and heat treatment, the preparation method is simple, the cost is low, the prepared lithium sulfur battery diaphragm has good conductivity, can effectively adsorb lithium polysulfide, provides a large number of active sites, efficiently catalyzes conversion between lithium polysulfide, and improves the cycle stability of the lithium sulfur battery.
Description
Technical Field
The invention belongs to the technical field of lithium batteries, and relates to a lithium-sulfur battery diaphragm, a preparation method thereof and a lithium-sulfur battery.
Background
Currently, with the continuous development and progress of society, people's life is increasingly dependent on portable electronic equipment, electric vehicles and other energy storage devices, and although lithium ion battery technology is very popular and applied at present, the lithium ion battery technology cannot meet the needs of people due to low specific capacity. Lithium sulfur battery due to its high contentTheoretical energy Density (2567 Wh kg) -1 ) High theoretical specific capacity (1675 mAh g) -1 ) Lower cost and environmental friendliness are considered to be one of the most promising energy storage systems. However, with the intensive research, slow redox kinetics of intermediate polysulfides during battery charging and discharging cause a decrease in coulombic efficiency; in addition, the lithium-sulfur battery has a shuttle effect of polysulfide in the charge and discharge process, and the shuttle effect has serious corrosion effect on a lithium anode, and further causes sulfur loss, so that the battery performance is seriously influenced.
CN109346678A provides a high sulfur-loaded lithium sulfur battery positive electrode material, which is prepared by performing nano ball milling on a carbon material and sulfur, heating and melting to obtain a carbon-sulfur composite positive electrode material, and then performing nano ball milling on a conductive agent, an adhesive and the carbon-sulfur composite positive electrode material to obtain a lithium sulfur battery positive electrode material, wherein carbon has a fixing effect on sulfur; the method has the advantages of low raw material cost, simple process, controllable process and high sulfur load. CN109950472B discloses a positive electrode material of lithium-sulfur battery and a preparation method thereof, which is obtained by melting sulfur powder and organic matters, wherein the organic matters have a sulfur fixation effect, the material has higher sulfur content, and the energy density of the battery is improved. CN111933948A discloses a lithium sulfur battery, which is prepared by mixing and heating graphene oxide and lithium powder as a negative electrode material, and has higher energy density and charge-discharge efficiency.
The current research on lithium sulfur batteries is focused on improving the sulfur fixing performance of the anode material and the cathode material of the batteries, but the addition of sulfur fixing substances into the battery materials can reduce the energy density of the batteries to a certain extent, so that the research on the sulfur fixing performance of the battery separator is very important. The problems of poor polysulfide shuttle inhibiting effect, high cost, unfavorable mass production and the like still exist in the improvement of the diaphragm in the prior art, and the further application of the lithium sulfur battery is limited.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a lithium-sulfur battery diaphragm, a preparation method thereof and a lithium-sulfur battery. The lithium sulfur battery diaphragm is prepared by a one-pot method and heat treatment, the preparation method is simple, the cost is low, the prepared lithium sulfur battery diaphragm has good conductivity, can effectively adsorb lithium polysulfide, provides a large number of active sites, efficiently catalyzes conversion between lithium polysulfide, and improves the cycle stability of the lithium sulfur battery.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the invention provides a lithium-sulfur battery separator, which comprises a separator substrate and a separator coating arranged on the surface of the separator substrate, wherein the separator coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite.
The invention uses Fe 3 O 4 The compound of the carbon nano tube and the carbon fiber is loaded on the surface of the diaphragm matrix and Fe is utilized 3 O 4 The synergistic effect among the carbon nano tube and the carbon fiber suppresses the shuttle effect of lithium polysulfide and improves the conductivity and the cycling stability of the lithium sulfur battery. The technical principle is as follows: first, fe 3 O 4 Can effectively adsorb the lithium polysulfide and catalyze the conversion of the lithium polysulfide; the second, carbon nanotube and carbon fiber have good conductivity, the branch-shaped structure that both present can shorten the lithium ion transmission path effectively, combine the two can form the three-dimensional conductive network at the same time, prevent the gathering of the carbon nanotube, help electrolyte to store and ion migration, can also be Fe 3 O 4 The method provides more loading space, combines the factors, can effectively anchor and catalyze the lithium polysulfide chemically, provides a large number of active sites on the surface of the diaphragm, and effectively catalyzes the conversion between the lithium polysulfide.
In comparison with the addition of sulfur-fixing substances to electrode materials, the invention is prepared by adding a catalyst containing Fe 3 O 4 The membrane coating of the carbon nano tube/carbon fiber composite is combined with the membrane matrix, so that physical separation and chemical adsorption can be simultaneously carried out, and the shuttle effect of lithium polysulfide is reduced to a greater extent. Meanwhile, compared with the electrode material, the lithium sulfur battery diaphragm provided by the invention can provide more anchoring sites for sulfur, so that the existence of dead sulfur is greatly reduced.
Preferably, with the Fe 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the Fe is as follows 3 O 4 The content of (2) is 30 to 75%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc., preferably 50 to 70%.
Preferably, with the Fe 3 O 4 The carbon nanotube/carbon fiber composite has a mass of 20 to 60%, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%, and preferably 25 to 45%, based on 100%.
Preferably, with the Fe 3 O 4 The carbon fiber content is 1-20%, for example, 1%, 2%, 3%, 5%, 8%, 10%, 12%, 15% or 20%, etc., preferably 5-10%, based on 100% of the mass of the carbon nanotube/carbon fiber composite. Fe of the present invention 3 O 4 The higher and lower carbon fiber content in the carbon nanotube/carbon fiber composite can have an effect on the electrochemical performance of the lithium sulfur battery.
Preferably, the Fe 3 O 4 Is Fe 3 O 4 Nanoparticles, fe 3 O 4 Nanoparticle at Fe 3 O 4 The dispersibility in the carbon nano tube/carbon fiber composite is better, and the proper particle size is more favorable for adsorbing lithium polysulfide.
Preferably, the membrane substrate is a polypropylene membrane.
Preferably, the separator coating further comprises a binder and a conductive agent.
Preferably, the binder comprises PVDF.
Preferably, the conductive agent includes conductive carbon black.
In a second aspect, the present invention provides a method for preparing a lithium sulfur battery separator according to the first aspect, the method comprising the steps of:
(1) Fe is added to 3 O 4 Mixing carbon nanotubes and carbon fibers in a solvent to obtain a mixed solution;
(2) Drying the mixed solution obtained in the step (1) and then performing heat treatment to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(3) Subjecting the Fe of step (2) 3 O 4 And (3) adding the carbon nano tube/carbon fiber composite into a solvent to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying to obtain the lithium-sulfur battery diaphragm.
The invention is implemented by mixing Fe 3 O 4 The carbon nano tube and the carbon fiber are mixed in the solvent, and the mixture is subjected to heat treatment and coated on the surface of the diaphragm matrix to obtain the lithium-sulfur battery diaphragm, and the one-pot method is simple and easy to operate, can reduce the cost to a great extent, and is beneficial to large-scale production; at the same time, heat treatment causes Fe to 3 O 4 Uniformly anchored on a three-dimensional network built by the carbon nano tube and the carbon fiber, and the three are good in combination property, and can be used as a carrier for absorbing polysulfide, so that the shuttle effect is more effectively inhibited, and the cycling stability of the lithium-sulfur battery is improved.
Preferably, the Fe of step (1) 3 O 4 Is Fe 3 O 4 And (3) nanoparticles.
Preferably, the Fe 3 O 4 The preparation method of the nano-particles comprises the following steps:
(a) Dissolving an iron source and sodium oleate in a solvent, heating and refluxing to obtain a layering liquid;
(b) Drying the upper layer liquid of the layering liquid to obtain ferric oleate;
(c) Mixing the iron oleate and oleic acid in a compound solvent, heating and drying to obtain Fe 3 O 4 A nanoparticle;
the compound solvent is a mixed solvent of at least two of tetradecene, octadecene, trioctylamine or diphenyl ether, for example, a mixed solvent of tetradecene and octadecene, a mixed solvent of octadecene and trioctylamine, a mixed solvent of trioctylamine and diphenyl ether, a mixed solvent of octadecene and diphenyl ether, or a mixed solvent of octadecene, trioctylamine and diphenyl ether, and the like, and is preferably a mixed solvent of octadecene and diphenyl ether.
Synthesis of Fe using a Mixed solvent of octadecene and diphenyl ether 3 O 4 The nano particles can improve the uniformity of the particle size, so that the nano particles are loaded on a lithium-sulfur battery diaphragm to show more excellent sulfur fixation and catalysis effects, and further the electrochemical performance of the lithium-sulfur battery is improved.
Preferably, in the mixed solvent of the octadecene and the diphenyl ether, the volume ratio of the octadecene to the diphenyl ether is (1-3): 1, for example, 1:1, 1.1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.3:1, 2.5:1, 2.8:1, 3:1 or the like can be adopted.
Preferably, the iron source of step (a) is ferric chloride.
Preferably, the molar ratio of the iron source to sodium oleate in step (a) is 1 (2.5-3), and may be, for example, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, or the like.
Preferably, the solvent in the step (a) is any one or a mixture solution of at least two of ethanol, distilled water or n-hexane, for example, a mixture solution of ethanol and distilled water, a mixture solution of distilled water and n-hexane, or a mixture solution of ethanol, distilled water and n-hexane, etc., preferably a mixture solution of ethanol, distilled water and n-hexane.
Preferably, the heating temperature in step (a) is 60-70deg.C, and may be, for example, 60deg.C, 61 deg.C, 62 deg.C, 63 deg.C, 65 deg.C, 68 deg.C or 70deg.C.
Preferably, the reflux time in step (a) is 3-6h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc.
Preferably, the temperature of the drying in the step (b) is 50-60 ℃, for example, 50 ℃, 51 ℃, 52 ℃, 53 ℃, 55 ℃, 58 ℃ or 60 ℃, etc., and the time is 12-24 hours, for example, 12 hours, 13 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours, etc.
Preferably, the heating in step (c) is performed by: the temperature is raised to 100-120 ℃ and kept for 1-3h, then the temperature is raised to the boiling point of the compound solvent and kept for 0.5-2h, wherein the temperature is raised to 100-120 ℃ and can be 100 ℃, 101 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃, and the like, the temperature is kept for 1-3h and can be h, 1.5h, 2h, 2.5h or 3h, and the temperature is raised to the boiling point of the compound solvent and kept for 0.5-2h and can be 0.5h, 0.8h, 1h, 1.5h or 2h, and the like.
In an alternative embodiment, step (c) is followed by heating and before drying, the preparation process further comprising the step of washing and centrifuging the heated product. For example, washing with n-hexane and acetone may be performed.
Preferably, the mixing of step (1) is: fe is added to 3 O 4 Dispersing in solvent, adding carbon nanotube and carbon fiber, and stirring.
Preferably, the mixing time in step (1) is 24-72h, for example 24h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h or 72h, etc.
Preferably, the solvent of step (1) is n-hexane.
Preferably, the temperature of the drying in the step (2) is 50-70 ℃, and may be, for example, 50 ℃, 51 ℃, 53 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, or the like.
Preferably, the temperature of the heat treatment in the step (2) is 500-700 ℃, for example, 500 ℃, 510 ℃, 530 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃ or the like, and the time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or the like.
Preferably, the heating rate of the heat treatment in the step (2) is 1-3 ℃/min, for example, 1 ℃/min, 1.5 ℃/min, 2 ℃/min, 2.5 ℃/min or 3 ℃/min, etc.
Preferably, in step (3), the Fe of step (2) 3 O 4 In the process of adding the carbon nano tube/carbon fiber compound into the solvent, the conductive agent and the binder are added into the solvent together.
Preferably, the solvent of step (3) is N-methylpyrrolidone.
Preferably, the temperature of the drying in the step (3) is 50-70 ℃, for example, 50 ℃, 51 ℃, 53 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃ or the like, and the time is 10-20 hours, for example, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours or the like.
As a preferable technical scheme of the preparation method, the preparation method comprises the following steps:
(1) Iron source is treatedAnd sodium oleate are dissolved in a solvent, heated and refluxed for 3-6 hours at 60-70 ℃ to obtain a layering liquid, the upper layer liquid of the layering liquid is taken and dried for 12-24 hours at 50-60 ℃ to obtain ferric oleate, the ferric oleate and the oleic acid are dissolved in a compound solvent, the temperature is raised to 100-120 ℃ and kept for 1-3 hours, then the temperature is raised to the boiling point of the compound solvent and kept for 0.5-2 hours, and Fe is obtained after washing, centrifugation and drying 3 O 4 A nanoparticle;
(2) Subjecting the Fe of step (1) 3 O 4 Dispersing the nano particles in a solvent, adding the carbon nano tubes and the carbon fibers, and mixing for 24-72 hours to obtain a mixed solution;
(3) Drying the mixed solution obtained in the step (2) at 50-70 ℃, and performing heat treatment at 500-700 ℃ for 1-3h to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(4) The Fe of the step (3) 3 O 4 Adding the carbon nano tube/carbon fiber composite, the conductive agent and the binder into a solvent to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying at 50-70 ℃ for 10-20 hours to obtain the lithium-sulfur battery diaphragm.
In a third aspect, the invention provides a lithium sulfur battery, comprising a positive electrode, a negative electrode and a separator, wherein the separator is the lithium sulfur battery separator according to the first aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention loads the compound of the three on the surface of the diaphragm matrix and utilizes Fe 3 O 4 The synergistic effect of the carbon nano tube and the carbon fiber can effectively anchor and catalyze the lithium polysulfide chemically, and provide a large number of active sites on the surface of the diaphragm to catalyze the conversion between the lithium polysulfide efficiently, inhibit the shuttle effect of the lithium polysulfide and improve the conductivity and the cycling stability of the lithium sulfur battery.
(2) The lithium-sulfur battery diaphragm is prepared by a one-pot method and heat treatment, the preparation method is simple, the cost is low, and meanwhile, fe is caused by heat treatment 3 O 4 Uniformly anchored on the carbon nano tube and the carbon fiber, and the three have good combination property and are used as carriers for absorbing polysulfide, thereby being more convenientThe shuttle effect is effectively inhibited, and the cycling stability of the lithium-sulfur battery is improved.
Drawings
Fig. 1 is a front SEM image of a lithium sulfur battery separator in example 1.
Fig. 2 is a cross-sectional SEM image of the lithium sulfur battery separator in example 1.
Fig. 3 is a graph of the cycle performance of the lithium sulfur battery separator in example 1 in a lithium sulfur battery.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides a lithium sulfur battery diaphragm, the front SEM (scanning electron microscope) diagram of which is shown in fig. 1, the cross-section SEM diagram of which is shown in fig. 2, the lithium sulfur battery diaphragm comprises a diaphragm substrate and a diaphragm coating arranged on the surface of the diaphragm substrate, and the diaphragm coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite, PVDF and conductive carbon black, with Fe as described 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the Fe is as follows 3 O 4 The content of the carbon nano tube is 60%, the content of the carbon nano tube is 35%, the content of the carbon fiber is 5%, and the diaphragm substrate is a polypropylene diaphragm (celgard 2500).
The preparation method of the lithium sulfur battery diaphragm comprises the following steps:
(1) Dissolving ferric chloride and sodium oleate in a mixed solvent of ethanol, distilled water and n-hexane in a volume ratio of 4:3:7 according to a molar ratio of 1:2.9, putting into a magnetic rotor, heating and refluxing for 6 hours at 70 ℃ to obtain a layered liquid with a brownish red upper layer and a colorless and transparent lower layer, removing the colorless and transparent lower layer, washing the brownish red upper layer liquid with distilled water for a plurality of times, removing excessive solvent in the upper layer liquid by using a rotary evaporator, putting the obtained viscous oily brownish red ferric oleate into a vacuum oven, drying for 24 hours at 60 ℃ to obtain ferric oleate, and dissolving the ferric oleate and oleic acid in octadecene in a volume ratio of 2:1 according to a molar ratio of 6.4:1And diphenyl ether, raising the temperature to 120 ℃ and preserving heat for 1.5 hours, raising the temperature to the boiling point of the compound solvent and preserving heat for 1 hour, raising the temperature to 4 ℃/min, washing with a mixed solution of normal hexane and acetone with the volume ratio of 1:5, centrifuging and drying to obtain Fe 3 O 4 A nanoparticle;
(2) Subjecting the Fe of step (1) 3 O 4 Dispersing the nano particles in n-hexane, adding the carbon nano tubes and the carbon fibers, and stirring for 50 hours to obtain a mixed solution;
(3) Drying the mixed solution in the step (2) in a blast drying oven at 60 ℃ to remove redundant solvent, and then performing heat treatment for 2 hours at 600 ℃ at a heating rate of 2 ℃/min under an argon atmosphere to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(4) The Fe of the step (3) 3 O 4 Mixing the carbon nano tube/carbon fiber compound, the conductive carbon black and PVDF in a mass ratio of 8:1:1, adding N-methyl pyrrolidone to adjust viscosity to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying at 60 ℃ for 12 hours to obtain the lithium sulfur battery diaphragm, wherein the surface density of an interlayer material in the lithium sulfur battery diaphragm is 0.5mg cm -2 。
The cycling performance of the lithium sulfur battery separator according to this example is shown in fig. 3.
Example 2
The embodiment provides a lithium sulfur battery diaphragm, which comprises a diaphragm substrate and a diaphragm coating arranged on the surface of the diaphragm substrate, wherein the diaphragm coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite, PVDF and conductive carbon black, with Fe as described 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the Fe is as follows 3 O 4 70%, 25% of carbon nanotubes, 5% of carbon fibers, and the separator matrix is a polypropylene separator (celgard 2500).
The preparation method of the lithium sulfur battery diaphragm comprises the following steps:
(1) Ferric chloride and sodium oleate are dissolved in the volume ratio of 1:2.5 by mol ratioAdding the mixture of ethanol, distilled water and normal hexane in a ratio of 4:3:7 into a magnetic rotor, heating and refluxing for 6 hours at 60 ℃ to obtain a layered liquid with a brownish red upper layer and a colorless and transparent lower layer, removing the colorless and transparent lower layer, washing the brownish red upper layer liquid with distilled water for several times, removing redundant solvent in the upper layer liquid by a rotary evaporator, placing the obtained viscous oily brownish red ferric oleate in a vacuum oven, drying for 24 hours at 50 ℃ to obtain ferric oleate, dissolving the ferric oleate and oleic acid in a mixed solvent of octadecene and diphenyl ether in a volume ratio of 3:1 in a molar ratio of 6.4:1, heating to 100 ℃ for 3 hours, then heating to the boiling point of the compound solvent for 0.5 hours, heating rate for 3 ℃/min, washing by the mixed solution of normal hexane and acetone in a volume ratio of 1:8, centrifuging and drying to obtain Fe 3 O 4 A nanoparticle;
(2) Subjecting the Fe of step (1) 3 O 4 Dispersing the nano particles in n-hexane, adding the carbon nano tubes and the carbon fibers, and stirring for 30 hours to obtain a mixed solution;
(3) Drying the mixed solution in the step (2) in a 70 ℃ forced air drying box to remove redundant solvent, and then carrying out heat treatment for 1h at 700 ℃ at a heating rate of 3 ℃/min under an argon atmosphere to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(4) The Fe of the step (3) 3 O 4 Mixing the carbon nano tube/carbon fiber compound, the conductive carbon black and PVDF in a mass ratio of 8:1:1, adding N-methyl pyrrolidone to adjust viscosity to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying at 70 ℃ for 10 hours to obtain the lithium sulfur battery diaphragm, wherein the surface density of an interlayer material in the lithium sulfur battery diaphragm is 0.4mg cm -2 。
Example 3
The embodiment provides a lithium sulfur battery diaphragm, which comprises a diaphragm substrate and a diaphragm coating arranged on the surface of the diaphragm substrate, wherein the diaphragm coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite, PVDF and conductive carbon black, with Fe as described 3 O 4 Carbon nanotube/carbon fiber compositeThe mass of Fe is 100 percent 3 O 4 The content of the carbon nano tube is 40%, the content of the carbon nano tube is 50%, the content of the carbon fiber is 10%, and the diaphragm substrate is a polypropylene diaphragm (celgard 2500).
The preparation method of the lithium sulfur battery diaphragm comprises the following steps:
(1) Dissolving ferric chloride and sodium oleate in a mixed solvent of ethanol, distilled water and normal hexane in a volume ratio of 4:3:7 in a molar ratio of 1:3, putting into a magnetic rotor, heating and refluxing for 3h at 70 ℃ to obtain a layered liquid with a brownish red upper layer and a colorless and transparent lower layer, removing the colorless and transparent lower layer, washing the brownish red upper layer liquid with distilled water for several times, removing excessive solvent in the upper layer liquid by using a rotary evaporator, putting the obtained viscous oily brownish red ferric oleate into a vacuum oven, drying for 12h at 60 ℃ to obtain ferric oleate, dissolving the ferric oleate and oleic acid in a mixed solvent of octadecene and diphenyl ether in a volume ratio of 1.5:1 in a molar ratio of 6.4:1, keeping the temperature at 120 ℃ for 1.5h, then raising the temperature to the boiling point of the compound solvent for 2h, heating rate of 5 ℃/min, washing by using a mixed solution of normal hexane and acetone in a volume ratio of 1:4, centrifuging and drying to obtain Fe 3 O 4 A nanoparticle;
(2) Subjecting the Fe of step (1) 3 O 4 Dispersing the nano particles in n-hexane, adding the carbon nano tubes and the carbon fibers, and stirring for 60 hours to obtain a mixed solution;
(3) Drying the mixed solution in the step (2) in a blast drying oven at 55 ℃ to remove redundant solvent, and then performing heat treatment for 3 hours at 500 ℃ at a heating rate of 1 ℃/min under an argon atmosphere to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(4) The Fe of the step (3) 3 O 4 Mixing the carbon nano tube/carbon fiber compound, the conductive carbon black and PVDF in a mass ratio of 8:1:1, adding N-methyl pyrrolidone to adjust viscosity to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying at 65 ℃ for 15 hours to obtain the lithium sulfur battery diaphragm, wherein the surface density of an interlayer material in the lithium sulfur battery diaphragm is 0.7mg cm -2 。
Example 4
This example provides a lithium sulfur battery separator and a method for preparing the same, except Fe 3 O 4 The procedure of example 1 was repeated except that the carbon fiber content of the carbon nanotube/carbon fiber composite was 1%.
Example 5
This example provides a lithium sulfur battery separator and a method for preparing the same, except Fe 3 O 4 The procedure of example 1 was repeated except that the carbon fiber content of the carbon nanotube/carbon fiber composite was 20%.
Example 6
This example provides a lithium sulfur battery separator and a method for preparing the same, except for the absence of step (1) in the method for preparing, i.e., the commercial Fe is directly used 3 O 4 (I104317) preparation of lithium sulfur battery separator.
Example 7
The present example provided a lithium sulfur battery separator and a method for preparing the same, except that the mixing ratio of the mixed solvent of octadecene and diphenyl ether in step (1) was 0.9:1, the rest was the same as in example 1.
Example 8
This example provides a lithium sulfur battery separator and a method for producing the same, except that the mixed solvent of octadecene and diphenyl ether in step (1) was replaced with octadecene, the rest was the same as in example 1.
Example 9
This example provides a lithium sulfur battery separator and a method for producing the same, except that the mixed solvent of octadecene and diphenyl ether in step (1) was replaced with diphenyl ether, the remainder was the same as in example 1.
Comparative example 1
The comparative example provides a lithium-sulfur battery separator and a method for preparing the same, except that the separator coating of the lithium-sulfur battery separator does not contain Fe 3 O 4 Except for this, the procedure was the same as in example 1.
Comparative example 2
This comparative example provides a lithium sulfur battery separator and a method for preparing the same as in example 1 except that carbon nanotubes are not contained in the separator coating layer of the lithium sulfur battery separator.
Comparative example 3
This comparative example provides a lithium sulfur battery separator and a method for preparing the same as in example 1 except that carbon fiber is not contained in the separator coating layer of the lithium sulfur battery separator.
Comparative example 4
This comparative example provides a lithium sulfur battery separator and a method for preparing the same as in example 1 except that the heat treatment is not performed in step (3).
The lithium sulfur battery separators of examples 1 to 9 and comparative examples 1 to 4 were assembled into coin cells in a glove box, and the cycle performance of the cells was tested.
Assembling a button cell: physically mixing sublimed sulfur, conductive carbon black and PVDF in a ratio of sublimed sulfur to conductive carbon black of PVDF=7:2:1 to obtain positive electrode slurry, adding a proper amount of N-methyl pyrrolidone to adjust the viscosity of the positive electrode slurry, scraping active components in the positive electrode slurry on a carbon-coated aluminum foil after the active components are uniformly dispersed, and putting the positive electrode slurry into a vacuum oven for drying at 60 ℃ for 12 hours to obtain a positive electrode plate; cutting the dried positive electrode plate film into positive electrode plates with the diameter of d=12mm by using a cutting machine with the diameter of phi=12mm, selecting positive electrode plates with the same mass, and weighing to serve as the positive electrode of the button cell; positive electrode, lithium sheet negative electrode, lithium sulfur electrolyte containing 2% lini 3 were assembled with lithium sulfur battery separators of examples 1 to 9 and comparative examples 1 to 4 to obtain coin cells.
And (3) testing the cycle performance: the prepared coin cell was allowed to stand for 12 hours, circulated for 600 cycles at a high current of 1C, and the specific discharge capacity and the capacity attenuation rate of the cell after 600 cycles were recorded, wherein the average capacity attenuation rate per cycle= (specific discharge capacity of the first cycle-specific discharge capacity after 600 cycles)/600 specific discharge capacities of the first cycle, and the test results are shown in table 1.
TABLE 1
According to the embodiment 1-9, the lithium sulfur battery diaphragm is prepared by a one-pot method and heat treatment, the preparation method is simple, the cost is low, the prepared lithium sulfur battery diaphragm has good conductivity, can effectively adsorb lithium polysulfide, provides a large number of active sites, efficiently catalyzes conversion between lithium polysulfide, improves the cycling stability of the lithium sulfur battery, and meanwhile, the battery has higher first-turn discharge specific capacity.
As can be seen from a comparison of example 1 with examples 4 to 5, fe 3 O 4 The carbon fiber content in the carbon nanotube/carbon fiber composite can influence the performance of the prepared lithium sulfur battery diaphragm, and the higher or lower carbon fiber content can influence the cycle stability of the prepared lithium sulfur battery, so that the discharge specific capacity after 600 circles of examples 4-5 is lower than that of example 1, and the average capacity attenuation rate per circle is slightly higher than that of example 1.
As can be seen from a comparison of example 1 with example 6, the present invention preferably provides Fe 3 O 4 The preparation method of the nano particles is more beneficial to improving the cycling stability of the lithium-sulfur battery diaphragm, and the Fe prepared in the embodiment 1 3 O 4 The nanoparticles have the advantages of small particle size, good monodispersity and the like, so that the cycling stability of the embodiment 1 is higher than that of the embodiment 6.
As can be seen from a comparison of example 1 with examples 7 to 9, fe was produced in the present invention 3 O 4 When the nano particles are prepared, the selection and the proportion of the compound solvent can influence Fe 3 O 4 Nanoparticles, thereby affecting the cycling stability of lithium sulfur batteries; in example 1, a mixed solvent of octadecene and diphenyl ether was used, and the two solvents were mixed and mixed at the same time to synthesize Fe at a proper mixing ratio 3 O 4 The nanoparticles are more suitable for the preparation of lithium sulfur battery separators, and thus the cycling stability of example 1 is higher than examples 7-9.
As can be seen from a comparison of example 1 with comparative examples 1 to 3, fe in the present invention 3 O 4 The carbon nano tube and the carbon fiber play a role inThe synergistic effect of the three components is not achieved, and the Fe is absent 3 O 4 The adsorption and catalytic performance of polysulfide can be greatly weakened, the enhancement of polysulfide redox reaction kinetics is not facilitated, and the battery can not realize longer circulation; the lack of carbon nanotubes causes Fe to be 3 O 4 No carrier is present, resulting in Fe 3 O 4 The agglomeration of the active exposed sites is greatly reduced; the lack of carbon fibers reduces the functional layer conductivity such that the ion transport rate and electron conduction rate do not correspond well.
As is clear from a comparison of example 1 and comparative example 4, the heat treatment of the present invention affects the electrochemical properties of the prepared lithium sulfur battery separator, and comparative example 4, in which no heat treatment is performed, fe 3 O 4 The nano particles cannot be successfully anchored on the carbon nano tubes and the carbon fibers, and the effects of uniform dispersion and strong binding force cannot be realized, so that the problems of short circuit and the like of the battery are very easy to occur in the charging and discharging process of the battery, and longer circulation cannot be performed; prepared using heat treatment in example 1, fe 3 O 4 The nano particles, the carbon nano tubes and the carbon fibers have good binding property, the carbon nano tubes and the carbon fiber skeletons have the characteristic of high graphitization, and the nano particles can be used for more efficiently adsorbing and catalyzing polysulfide, inhibiting the shuttle effect and improving the stability of the lithium-sulfur battery, so that the stability of the embodiment 1 is higher.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.
Claims (34)
1. A preparation method of a lithium-sulfur battery diaphragm is characterized in that the lithium-sulfur battery diaphragm comprises a diaphragm substrate and a diaphragm coating arranged on the surface of the diaphragm substrate, and the diaphragm coating comprises Fe 3 O 4 Carbon nanotube/carbon fiber composite;
the preparation method comprises the following steps:
(1) Fe is added to 3 O 4 Mixing carbon nanotubes and carbon fibers in a solvent to obtain a mixed solution;
(2) Drying the mixed solution obtained in the step (1) and then performing heat treatment to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(3) Subjecting the Fe of step (2) 3 O 4 And (3) adding the carbon nano tube/carbon fiber composite into a solvent to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying to obtain the lithium-sulfur battery diaphragm.
2. The method according to claim 1, wherein the Fe is used as the catalyst 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the Fe is as follows 3 O 4 The content of (2) is 30-75%.
3. The preparation method according to claim 2, wherein the Fe is used as the catalyst 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the Fe is as follows 3 O 4 The content of (2) is 50-70%.
4. The method according to claim 1, wherein the Fe is used as the catalyst 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the content of the carbon nano tube is 20 to 60 percent.
5. The method according to claim 4, wherein the Fe is 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the content of the carbon nano tube is 25-45 percent.
6. The method according to claim 1, wherein the Fe is used as the catalyst 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the content of the carbon fiber is 1-20 percent.
7. The method according to claim 6, wherein the Fe is 3 O 4 The mass of the carbon nano tube/carbon fiber composite is 100 percent, and the content of the carbon fiber is 5-10 percent.
8. The method according to claim 1, wherein the Fe 3 O 4 Is Fe 3 O 4 And (3) nanoparticles.
9. The method of claim 1, wherein the separator substrate is a polypropylene separator.
10. The method of manufacturing according to claim 1, wherein the separator coating further comprises a binder and a conductive agent.
11. The method of manufacturing of claim 10, wherein the binder comprises PVDF.
12. The method of manufacturing according to claim 10, wherein the conductive agent comprises conductive carbon black.
13. The method according to claim 8, wherein the Fe 3 O 4 The preparation method of the nano-particles comprises the following steps:
(a) Dissolving an iron source and sodium oleate in a solvent, heating and refluxing to obtain a layering liquid;
(b) Drying the upper layer liquid of the layering liquid to obtain ferric oleate;
(c) Mixing the iron oleate and oleic acid in a compound solvent, heating and drying to obtain Fe 3 O 4 A nanoparticle;
wherein the compound solvent is a mixed solvent of at least two of tetradecene, octadecene, trioctylamine or diphenyl ether.
14. The method according to claim 13, wherein the compound solvent is a mixed solvent of octadecene and diphenyl ether.
15. The method according to claim 14, wherein the volume ratio of said octadecene to said diphenyl ether in said mixed solvent of octadecene and diphenyl ether is (1-3): 1.
16. The method of claim 13, wherein the iron source in step (a) is ferric chloride.
17. The method of claim 13, wherein the molar ratio of iron source to sodium oleate in step (a) is 1 (2.5-3).
18. The method according to claim 13, wherein the solvent in the step (a) is any one of ethanol, distilled water, and n-hexane or a mixed solution of at least two of them.
19. The method of claim 18, wherein the solvent in step (a) is a mixed solution of ethanol, distilled water and n-hexane.
20. The method of claim 13, wherein the heating in step (a) is at a temperature of 60-70 ℃.
21. The method of claim 13, wherein the reflux time of step (a) is 3-6 hours.
22. The method of claim 13, wherein the drying in step (b) is performed at a temperature of 50-60 ℃ for a period of 12-24 hours.
23. The method of claim 13, wherein the heating in step (c) is performed by: raising the temperature to 100-120 ℃ and preserving the heat for 1-3h, and then raising the temperature to the boiling point of the compound solvent and preserving the boiling point for 0.5-2h.
24. The method of claim 1, wherein the mixing in step (1) is: fe is added to 3 O 4 Dispersing in solvent, adding carbon nanotube and carbon fiber, and stirring.
25. The method of claim 1, wherein the mixing in step (1) is for a period of 24 to 72 hours.
26. The method of claim 1, wherein the solvent in step (1) is n-hexane.
27. The method of claim 1, wherein the drying in step (2) is performed at a temperature of 50-70 ℃.
28. The method according to claim 1, wherein the heat treatment in step (2) is performed at a temperature of 500 to 700 ℃ for a time of 1 to 3 hours.
29. The method according to claim 1, wherein the heating rate of the heat treatment in the step (2) is 1 to 3 ℃/min.
30. The method according to claim 1, wherein the Fe of step (2) is added in step (3) 3 O 4 In the process of adding the carbon nano tube/carbon fiber compound into the solvent, the conductive agent and the binder are added into the solvent together.
31. The method according to claim 1, wherein the solvent in the step (3) is N-methylpyrrolidone.
32. The method according to claim 1, wherein the drying in step (3) is carried out at a temperature of 50 to 70 ℃ for a time of 10 to 20 hours.
33. The preparation method according to claim 1, characterized in that the preparation method comprises:
(1) Dissolving iron source and sodium oleate in a solvent, heating at 60-70 ℃ and refluxing for 3-6 hours to obtain a layering liquid, taking an upper layer liquid of the layering liquid, drying at 50-60 ℃ for 12-24 hours to obtain iron oleate, dissolving the iron oleate and the oleic acid in a compound solvent, raising the temperature to 100-120 ℃ and preserving heat for 1-3 hours, raising the temperature to the boiling point of the compound solvent and preserving heat for 0.5-2 hours, washing, centrifuging and drying to obtain Fe 3 O 4 A nanoparticle;
(2) Subjecting the Fe of step (1) 3 O 4 Dispersing the nano particles in a solvent, adding the carbon nano tubes and the carbon fibers, and mixing for 24-72 hours to obtain a mixed solution;
(3) Drying the mixed solution obtained in the step (2) at 50-70 ℃, and performing heat treatment at 500-700 ℃ for 1-3h to obtain Fe 3 O 4 Carbon nanotube/carbon fiber composite;
(4) The Fe of the step (3) 3 O 4 Adding the carbon nano tube/carbon fiber composite, the conductive agent and the binder into a solvent to obtain coating slurry, coating the coating slurry on the surface of a diaphragm substrate, and drying at 50-70 ℃ for 10-20 hours to obtain the lithium-sulfur battery diaphragm.
34. A lithium sulfur battery comprising a positive electrode, a negative electrode and a separator, wherein the separator is prepared by the preparation method of any one of claims 1-33.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111180708.6A CN113937418B (en) | 2021-10-11 | 2021-10-11 | Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111180708.6A CN113937418B (en) | 2021-10-11 | 2021-10-11 | Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113937418A CN113937418A (en) | 2022-01-14 |
| CN113937418B true CN113937418B (en) | 2023-11-17 |
Family
ID=79278064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111180708.6A Active CN113937418B (en) | 2021-10-11 | 2021-10-11 | Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113937418B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118783034A (en) * | 2023-04-07 | 2024-10-15 | 宁德时代新能源科技股份有限公司 | Battery separator, preparation method thereof, secondary battery and power utilization device |
Citations (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150128159A (en) * | 2014-05-08 | 2015-11-18 | 현대자동차주식회사 | A secondary battery comprising sulfur particle having core-shell structure |
| CN105489818A (en) * | 2015-12-29 | 2016-04-13 | 长沙矿冶研究院有限责任公司 | Preparation method for modified diaphragm for lithium-sulfur battery, modified diaphragm and lithium-sulfur battery adopting modified diaphragm |
| 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 |
| CN106935773A (en) * | 2015-12-31 | 2017-07-07 | 中国人民解放军63971部队 | A kind of interlayer for lithium-sulfur cell |
| CN107887605A (en) * | 2017-10-25 | 2018-04-06 | 天津赫维科技有限公司 | One kind is based on active MnO2The preparation method of the lithium-sulphur cell positive electrode of catalysis |
| CN107910584A (en) * | 2017-10-23 | 2018-04-13 | 西安理工大学 | A kind of production method of Soft Roll lithium-sulfur cell |
| CN108336308A (en) * | 2017-01-20 | 2018-07-27 | 华为技术有限公司 | A kind of lithium-sulphur cell positive electrode protection materials and its application |
| WO2018148233A1 (en) * | 2017-02-09 | 2018-08-16 | University Of California, Los Angeles | Regenerative polysulfide-scavenging layers enabling lithium-sulfur batteries with high energy density and prolonged cycling life and methods of making same |
| CN109309216A (en) * | 2018-08-20 | 2019-02-05 | 中国航发北京航空材料研究院 | A kind of preparation method of lithium sulfur battery anode material |
| CN109449425A (en) * | 2018-11-20 | 2019-03-08 | 肇庆市华师大光电产业研究院 | A kind of preparation method of lithium-sulfur cell composite material and the application of the composite material |
| CN109461865A (en) * | 2017-09-06 | 2019-03-12 | 中南大学 | A kind of preparation method of coating polyetherimide diaphragm and the application in lithium-sulfur cell |
| WO2019066366A1 (en) * | 2017-09-28 | 2019-04-04 | 주식회사 엘지화학 | Titania-carbon nanotube-sulfur (tio2-x-cnt-s) composite and preparing method therefor |
| CN109786748A (en) * | 2018-12-29 | 2019-05-21 | 桑德集团有限公司 | A kind of lithium-sulphur cell positive electrode piece and preparation method thereof, lithium-sulfur cell |
| CN110492045A (en) * | 2019-08-27 | 2019-11-22 | 安徽新衡新材料科技有限公司 | A kind of lithium-sulfur cell diaphragm and its preparation method and application |
| CN110957455A (en) * | 2019-11-27 | 2020-04-03 | 烟台大学 | Functionalized diaphragm for lithium-sulfur battery and preparation method thereof |
| KR20200065828A (en) * | 2018-11-30 | 2020-06-09 | 한국과학기술연구원 | A composite membrane comprising a conductive material layer, and secondary cell battery, electrochemical element, and electrochemical device comprising the same, and the method thereof |
| CN111463414A (en) * | 2020-04-09 | 2020-07-28 | 中科院过程工程研究所南京绿色制造产业创新研究院 | Interlayer material and preparation method and application thereof |
| CN111463415A (en) * | 2020-04-09 | 2020-07-28 | 中科院过程工程研究所南京绿色制造产业创新研究院 | Positive host material and preparation method and application thereof |
| CA3128861A1 (en) * | 2019-02-05 | 2020-08-13 | Council Of Scientific & Industrial Research | A metal ion battery having ionomer membrane separator and free-standing electrode |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150124301A (en) * | 2014-04-28 | 2015-11-05 | 현대자동차주식회사 | A structure of cathode of lithium sulfur battery |
| EP3218479A1 (en) * | 2014-11-11 | 2017-09-20 | Nanocore ApS | Method for identification of molecules with desired characteristics |
-
2021
- 2021-10-11 CN CN202111180708.6A patent/CN113937418B/en active Active
Patent Citations (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150128159A (en) * | 2014-05-08 | 2015-11-18 | 현대자동차주식회사 | A secondary battery comprising sulfur particle having core-shell structure |
| CN105489818A (en) * | 2015-12-29 | 2016-04-13 | 长沙矿冶研究院有限责任公司 | Preparation method for modified diaphragm for lithium-sulfur battery, modified diaphragm and lithium-sulfur battery adopting modified diaphragm |
| CN106935773A (en) * | 2015-12-31 | 2017-07-07 | 中国人民解放军63971部队 | A kind of interlayer for lithium-sulfur cell |
| 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 |
| CN108336308A (en) * | 2017-01-20 | 2018-07-27 | 华为技术有限公司 | A kind of lithium-sulphur cell positive electrode protection materials and its application |
| WO2018148233A1 (en) * | 2017-02-09 | 2018-08-16 | University Of California, Los Angeles | Regenerative polysulfide-scavenging layers enabling lithium-sulfur batteries with high energy density and prolonged cycling life and methods of making same |
| CN109461865A (en) * | 2017-09-06 | 2019-03-12 | 中南大学 | A kind of preparation method of coating polyetherimide diaphragm and the application in lithium-sulfur cell |
| WO2019066366A1 (en) * | 2017-09-28 | 2019-04-04 | 주식회사 엘지화학 | Titania-carbon nanotube-sulfur (tio2-x-cnt-s) composite and preparing method therefor |
| CN107910584A (en) * | 2017-10-23 | 2018-04-13 | 西安理工大学 | A kind of production method of Soft Roll lithium-sulfur cell |
| CN107887605A (en) * | 2017-10-25 | 2018-04-06 | 天津赫维科技有限公司 | One kind is based on active MnO2The preparation method of the lithium-sulphur cell positive electrode of catalysis |
| CN109309216A (en) * | 2018-08-20 | 2019-02-05 | 中国航发北京航空材料研究院 | A kind of preparation method of lithium sulfur battery anode material |
| CN109449425A (en) * | 2018-11-20 | 2019-03-08 | 肇庆市华师大光电产业研究院 | A kind of preparation method of lithium-sulfur cell composite material and the application of the composite material |
| KR20200065828A (en) * | 2018-11-30 | 2020-06-09 | 한국과학기술연구원 | A composite membrane comprising a conductive material layer, and secondary cell battery, electrochemical element, and electrochemical device comprising the same, and the method thereof |
| CN109786748A (en) * | 2018-12-29 | 2019-05-21 | 桑德集团有限公司 | A kind of lithium-sulphur cell positive electrode piece and preparation method thereof, lithium-sulfur cell |
| CA3128861A1 (en) * | 2019-02-05 | 2020-08-13 | Council Of Scientific & Industrial Research | A metal ion battery having ionomer membrane separator and free-standing electrode |
| CN110492045A (en) * | 2019-08-27 | 2019-11-22 | 安徽新衡新材料科技有限公司 | A kind of lithium-sulfur cell diaphragm and its preparation method and application |
| CN110957455A (en) * | 2019-11-27 | 2020-04-03 | 烟台大学 | Functionalized diaphragm for lithium-sulfur battery and preparation method thereof |
| CN111463414A (en) * | 2020-04-09 | 2020-07-28 | 中科院过程工程研究所南京绿色制造产业创新研究院 | Interlayer material and preparation method and application thereof |
| CN111463415A (en) * | 2020-04-09 | 2020-07-28 | 中科院过程工程研究所南京绿色制造产业创新研究院 | Positive host material and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113937418A (en) | 2022-01-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Xu et al. | Tri-functionalized polypropylene separator by rGO/MoO 2 composite for high-performance lithium–sulfur batteries | |
| CN107959010B (en) | Graphite composite material and preparation method thereof | |
| CN113451576B (en) | Graphite composite material, preparation method thereof and lithium ion battery | |
| CN114702022B (en) | Preparation method and application of hard carbon anode material | |
| CN111916640A (en) | Lithium sulfur battery WS2/CNTs modified diaphragm and preparation method thereof | |
| CN110240142A (en) | The porous carbon electrode material and its preparation method and application that microstructure is easy to regulate and control | |
| CN113193183A (en) | High-tap-density double-carbon-layer silicon-carbon composite material and preparation method thereof | |
| CN113594415A (en) | Sandwich independent positive electrode for inhibiting shuttle effect of lithium-sulfur battery and preparation method thereof | |
| Lei et al. | Crosslinked polyacrylonitrile precursor for S@ pPAN composite cathode materials for rechargeable lithium batteries | |
| CN111740110A (en) | Composite negative electrode material, preparation method thereof and lithium ion battery | |
| CN112017870A (en) | Coal-based porous carbon, preparation method and application thereof, and lithium ion capacitor | |
| CN110085823B (en) | Nano composite negative electrode material and preparation method and application thereof | |
| CN113937418B (en) | Lithium-sulfur battery diaphragm, preparation method thereof and lithium-sulfur battery | |
| CN113571702A (en) | Positive electrode matrix material of quasi-solid-state lithium-sulfur battery and preparation method and application thereof | |
| CN114105133B (en) | Graphite-silicon/silicon oxide-carbon composite material and preparation method and application thereof | |
| CN113594461B (en) | Carbon-silicon composite material and preparation method and application thereof | |
| CN114162814B (en) | Modification method of graphite | |
| CN114335558A (en) | Preparation method of conjugate microporous polyaniline modified battery current collector and application of conjugate microporous polyaniline modified battery current collector in lithium-sulfur battery | |
| CN111276683B (en) | Silicon dioxide sulfur positive electrode rich in aluminum hydroxyl and preparation method thereof | |
| CN109935821B (en) | SiO (silicon dioxide)xPreparation method of-G/PAA-PANI/graphene composite material | |
| CN114094058A (en) | Preparation method of lithium phosphide electrode based on microwave method | |
| CN112018356A (en) | Flaky potassium ion negative electrode material | |
| CN110739445A (en) | Preparation method of nitrogen-doped carbon/graphene/silicon self-supporting composite electrode | |
| CN112750993A (en) | Silicon-carbon composite material, preparation method thereof, negative electrode and battery | |
| CN114873632B (en) | Double-trifluoro lithium methanesulfonimide/zeolite imidazole ester skeleton composite material and 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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |