CN117335094A - Preparation method of high-entropy monoatomic catalyst modified diaphragm and application of high-entropy monoatomic catalyst modified diaphragm in lithium-sulfur battery - Google Patents
Preparation method of high-entropy monoatomic catalyst modified diaphragm and application of high-entropy monoatomic catalyst modified diaphragm in lithium-sulfur battery Download PDFInfo
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- CN117335094A CN117335094A CN202311267846.7A CN202311267846A CN117335094A CN 117335094 A CN117335094 A CN 117335094A CN 202311267846 A CN202311267846 A CN 202311267846A CN 117335094 A CN117335094 A CN 117335094A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 76
- JDZCKJOXGCMJGS-UHFFFAOYSA-N [Li].[S] Chemical compound [Li].[S] JDZCKJOXGCMJGS-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 238000002360 preparation method Methods 0.000 title claims abstract description 28
- 239000000463 material Substances 0.000 claims abstract description 53
- 229910052751 metal Inorganic materials 0.000 claims abstract description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 29
- 238000010438 heat treatment Methods 0.000 claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 29
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 24
- 239000003792 electrolyte Substances 0.000 claims abstract description 17
- 239000002243 precursor Substances 0.000 claims abstract description 17
- 238000002156 mixing Methods 0.000 claims abstract description 16
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 12
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052786 argon Inorganic materials 0.000 claims abstract description 6
- 150000003839 salts Chemical class 0.000 claims abstract description 6
- 229910017464 nitrogen compound Inorganic materials 0.000 claims abstract description 5
- 239000012528 membrane Substances 0.000 claims description 29
- GJEAMHAFPYZYDE-UHFFFAOYSA-N [C].[S] Chemical compound [C].[S] GJEAMHAFPYZYDE-UHFFFAOYSA-N 0.000 claims description 27
- 239000002002 slurry Substances 0.000 claims description 25
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 18
- 239000002033 PVDF binder Substances 0.000 claims description 18
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 14
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 14
- 229910052744 lithium Inorganic materials 0.000 claims description 14
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims description 12
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000006229 carbon black Substances 0.000 claims description 12
- 239000011248 coating agent Substances 0.000 claims description 12
- 238000000576 coating method Methods 0.000 claims description 12
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical group [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 claims description 12
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 11
- 229920000877 Melamine resin Polymers 0.000 claims description 10
- 238000001354 calcination Methods 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 10
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- -1 polytetrafluoroethylene Polymers 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
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- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 claims description 6
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 6
- 239000000654 additive Substances 0.000 claims description 6
- 230000000996 additive effect Effects 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 239000007853 buffer solution Substances 0.000 claims description 6
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- 239000002048 multi walled nanotube Substances 0.000 claims description 6
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- 238000001132 ultrasonic dispersion Methods 0.000 claims description 6
- 238000001291 vacuum drying Methods 0.000 claims description 6
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- CTENFNNZBMHDDG-UHFFFAOYSA-N Dopamine hydrochloride Chemical compound Cl.NCCC1=CC=C(O)C(O)=C1 CTENFNNZBMHDDG-UHFFFAOYSA-N 0.000 claims description 5
- 239000011247 coating layer Substances 0.000 claims description 5
- 229960001149 dopamine hydrochloride Drugs 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- LENZDBCJOHFCAS-UHFFFAOYSA-N tris Chemical compound OCC(N)(CO)CO LENZDBCJOHFCAS-UHFFFAOYSA-N 0.000 claims description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 4
- VYFYYTLLBUKUHU-UHFFFAOYSA-N dopamine Chemical compound NCCC1=CC=C(O)C(O)=C1 VYFYYTLLBUKUHU-UHFFFAOYSA-N 0.000 claims description 4
- 238000000227 grinding Methods 0.000 claims description 4
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims description 4
- ZXMGHDIOOHOAAE-UHFFFAOYSA-N 1,1,1-trifluoro-n-(trifluoromethylsulfonyl)methanesulfonamide Chemical compound FC(F)(F)S(=O)(=O)NS(=O)(=O)C(F)(F)F ZXMGHDIOOHOAAE-UHFFFAOYSA-N 0.000 claims description 2
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- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 2
- 239000001263 FEMA 3042 Substances 0.000 claims description 2
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 2
- LRBQNJMCXXYXIU-PPKXGCFTSA-N Penta-digallate-beta-D-glucose Natural products OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-PPKXGCFTSA-N 0.000 claims description 2
- 229920002125 Sokalan® Polymers 0.000 claims description 2
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- 239000012298 atmosphere Substances 0.000 claims description 2
- 239000004202 carbamide Substances 0.000 claims description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 2
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims description 2
- 229960003638 dopamine Drugs 0.000 claims description 2
- DBLXOVFQHHSKRC-UHFFFAOYSA-N ethanesulfonic acid;2-piperazin-1-ylethanol Chemical compound CCS(O)(=O)=O.OCCN1CCNCC1 DBLXOVFQHHSKRC-UHFFFAOYSA-N 0.000 claims description 2
- 239000008103 glucose Substances 0.000 claims description 2
- 235000001727 glucose Nutrition 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 229910001510 metal chloride Inorganic materials 0.000 claims description 2
- 229910001960 metal nitrate Inorganic materials 0.000 claims description 2
- 239000008055 phosphate buffer solution Substances 0.000 claims description 2
- 239000004584 polyacrylic acid Substances 0.000 claims description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 2
- 230000001681 protective effect Effects 0.000 claims description 2
- 229940033123 tannic acid Drugs 0.000 claims description 2
- 229920002258 tannic acid Polymers 0.000 claims description 2
- LRBQNJMCXXYXIU-NRMVVENXSA-N tannic acid Chemical compound OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-NRMVVENXSA-N 0.000 claims description 2
- 235000015523 tannic acid Nutrition 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 229910052717 sulfur Inorganic materials 0.000 abstract description 18
- 239000011593 sulfur Substances 0.000 abstract description 18
- 238000006479 redox reaction Methods 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 9
- 238000006243 chemical reaction Methods 0.000 abstract description 8
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 7
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 7
- 230000005540 biological transmission Effects 0.000 abstract description 6
- 230000004048 modification Effects 0.000 abstract description 6
- 238000012986 modification Methods 0.000 abstract description 6
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- 238000012360 testing method Methods 0.000 description 9
- 230000003197 catalytic effect Effects 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 6
- 229910017052 cobalt Inorganic materials 0.000 description 6
- 239000010941 cobalt Substances 0.000 description 6
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 6
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 description 6
- 229920001155 polypropylene Polymers 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 5
- 230000008020 evaporation Effects 0.000 description 5
- 230000010287 polarization Effects 0.000 description 5
- 239000005077 polysulfide Substances 0.000 description 5
- 229920001021 polysulfide Polymers 0.000 description 5
- 150000008117 polysulfides Polymers 0.000 description 5
- 239000007772 electrode material Substances 0.000 description 4
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 4
- 238000005303 weighing Methods 0.000 description 4
- 239000012300 argon atmosphere Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000006255 coating slurry Substances 0.000 description 3
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 3
- 239000012691 Cu precursor Substances 0.000 description 2
- 239000012692 Fe precursor Substances 0.000 description 2
- 239000012697 Mn precursor Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 230000014233 sulfur utilization Effects 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 229910021591 Copper(I) chloride Inorganic materials 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000002466 imines Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- GLNWILHOFOBOFD-UHFFFAOYSA-N lithium sulfide Chemical compound [Li+].[Li+].[S-2] GLNWILHOFOBOFD-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
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- 230000003287 optical effect Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 125000001889 triflyl group Chemical group FC(F)(F)S(*)(=O)=O 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
- H01M50/403—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
- 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
- H01M50/409—Separators, membranes or diaphragms characterised by the 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention belongs to the technical field of battery materials, and particularly relates to a preparation method of a high-entropy single-atom catalyst modified diaphragm and application of the high-entropy single-atom catalyst modified diaphragm in a lithium-sulfur battery. And mixing different soluble metal salts with a carbon nitrogen compound, performing heat treatment to obtain a precursor, and transferring metal atoms on the precursor to a nitrogen-doped carbon carrier through high-temperature argon treatment to obtain the high-entropy single-atom catalyst which can be used as a modification material of a diaphragm in a lithium-sulfur battery. The high-entropy monoatomic catalyst modified diaphragm prepared by the method greatly improves the wettability of the diaphragm to electrolyte, is used for accelerating the kinetics of the redox reaction of sulfur in a lithium-sulfur battery, inhibits the shuttle effect, and can accelerate the transmission of lithium ions at a positive electrode/diaphragm reaction interface, so that the lithium-sulfur battery has excellent cycle performance and rate capability. The preparation method is simple in preparation process, the content of each metal component is easy to regulate and control, and the preparation method has a good application prospect.
Description
Technical field:
the invention belongs to the technical field of battery materials, and particularly relates to a preparation method of a high-entropy single-atom catalyst modified diaphragm and application of the high-entropy single-atom catalyst modified diaphragm in a lithium-sulfur battery.
The background technology is as follows:
with the rapid increase in energy density requirements of energy storage devices, lithium sulfur batteries are considered to be one of the most potential new generation energy storage devices. Simple sulfur has rich reserve, low price, environmental protection and high theoretical specific capacity (1675 mAh g) -1 ) The theoretical energy density of a lithium-sulfur battery system consisting of a lithium negative electrode and a sulfur positive electrode is as high as 2670Wh kg -1 Far higher than commercial lithium ion batteries. However, due to the problems of low sulfur utilization rate, rapid capacity decay and the like caused by long-chain polysulfide dissolution, shuttle effect and slow redox reaction kinetics caused by the electronic insulation of sulfur and discharge end product lithium sulfide, the commercial application of lithium-sulfur batteries is seriously hindered.
At present, one of the most effective strategies for solving the problems is to introduce a catalyst for sulfur reduction reaction into a modified material of a sulfur anode or a diaphragm, which can effectively adsorb lithium polysulfide and reduce the reaction activation energy, and plays roles of inhibiting a shuttle effect and accelerating reaction kinetics, thereby improving the capacity and the cycle stability of a lithium-sulfur battery. The metal monoatomic catalyst is widely applied in the field of lithium sulfur batteries due to the unique geometric and electronic characteristics, the maximum atom utilization rate and other advantages, but the improvement of the performance of the lithium sulfur batteries is limited due to the low content of the monodisperse metal atoms which can be loaded by the carrier material.
Based on this, in order to further improve the catalytic efficiency of the metal monoatomic catalyst, more kinds of metal elements can be introduced into the monoatomic system, a high-entropy monoatomic catalytic material is obtained, and is used as a membrane modification material. The high-entropy monoatomic catalytic material has rich active sites and synergistic effect among different active sites, can greatly improve the redox reaction kinetics of sulfur, and shows excellent electrochemical performance when the modified diaphragm is used for a lithium-sulfur battery.
The invention comprises the following steps:
the invention aims to provide a preparation method of a high-entropy single-atom catalyst modified diaphragm and application of the high-entropy single-atom catalyst modified diaphragm in a lithium sulfur battery, wherein the high-entropy single-atom catalyst loaded on a nitrogen-doped carbon matrix is prepared and used as a modified material of the lithium sulfur battery diaphragm. The diaphragm has excellent mechanical stability and good electrolyte affinity, can accelerate the redox reaction kinetics of sulfur, inhibit the shuttle effect, accelerate the transmission of lithium ions at a positive electrode/diaphragm reaction interface and improve the cycle performance and the rate capability of the lithium-sulfur battery when applied to the lithium-sulfur battery.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for preparing a high-entropy monoatomic catalyst modified diaphragm, which comprises the following steps:
(1) Mixing five or more soluble metal salts with carbon nitrogen compound respectively, stirring and heating in hydrochloric acid solution until the liquid is evaporated to dryness, and heat-treating the evaporated mixture to obtain a precursor material for loading metal;
(2) Uniformly mixing the precursor material loaded with the metal, stirring the mixture with an organic carbon source in a buffer solution for 24 hours, centrifuging and drying the mixture to obtain a high-entropy catalyst precursor, and carrying out high-temperature treatment on the high-entropy catalyst precursor in an inert protective atmosphere to obtain a high-entropy monoatomic catalyst material;
(3) And mixing and grinding the high-entropy monoatomic catalyst material and the binder, adding a solvent to obtain uniform slurry, coating the slurry on the surface of the battery diaphragm, and drying to obtain the high-entropy monoatomic catalyst modified diaphragm.
In the step (1), the soluble metal salt is metal chloride or metal nitrate of Fe, co, ni, cu, mn, cr, pt, pd element respectively, and the carbon-nitrogen compound is one of melamine, urea, dicyandiamide and thiourea.
In the preparation method of the high-entropy monoatomic catalyst modified diaphragm, in the step (1), the heat treatment process is as follows: placing the mixture after being evaporated to dryness in a muffle furnace, heating to 500-550 ℃ at a heating rate of 5-10 ℃/min, and calcining for 2-4 hours.
In the step (2), the organic carbon source is one of dopamine, dopamine hydrochloride, tannic acid, polyvinylpyrrolidone and glucose; the buffer solution is one of tris (hydroxymethyl) aminomethane, 4-hydroxyethyl piperazine ethane sulfonic acid, phosphate buffer solution and ammonia water-ammonium chloride buffer solution.
In the preparation method of the high-entropy single-atom catalyst modified diaphragm, in the step (2), the high-temperature treatment process is as follows: and (3) placing the high-entropy catalyst precursor in a tube furnace, heating to 800-1100 ℃ at a heating rate of 1-5 ℃/min under the protection of argon or nitrogen, and calcining for 2-4 hours.
In the step (2), all metal atoms of the high-entropy single-atom catalyst are uniformly dispersed on a nitrogen-doped carbon matrix, and the total metal content is 1-8wt%; in the nitrogen-doped carbon matrix, the nitrogen doping amount is 7-12 wt%.
In the step (3), the binder is one of polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose and polyacrylic acid; the solvent is one of N-methyl pyrrolidone and water.
In the preparation method of the high-entropy monoatomic catalyst modified diaphragm, in the step (3), the mass ratio of the high-entropy monoatomic catalyst material to the binder is 9:1 to 4:1, the solid content in the slurry is 7-12 wt%.
In the preparation method of the high-entropy single-atom catalyst modified diaphragm, in the step (3), the thickness of a coating layer of the high-entropy single-atom catalyst modified diaphragm is 5-50 mu m.
The application of the high-entropy monoatomic catalyst modified diaphragm prepared by the method in the lithium sulfur battery is that the preparation of the lithium sulfur battery comprises the following steps:
(1) Sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the following proportion (7-8): (2-1): adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 30-40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material;
(2) Sulfur-carbon positive electrode material, carbon black and polyvinylidene fluoride are mixed according to the following proportion (7-8): (2-1): 1, after evenly mixing and grinding, adding N-methyl pyrrolidone to obtain even slurry, wherein the solid content in the slurry is 15-20wt%, coating the slurry on the surface of a carbon-coated aluminum foil, and cutting into wafers with the diameter of 12mm after vacuum drying at 60 ℃ to obtain a sulfur-carbon polar plate;
(3) The button cell is assembled in a glove box filled with argon, the anode is a sulfur carbon pole piece, the cathode is metallic lithium, the diaphragm is a high-entropy single-atom catalyst modified diaphragm, the electrolyte is 1M bis (trifluoromethylsulfonyl) imide lithium in molar concentration, the electrolyte is dissolved in a mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1, and the additive is lithium nitrate with a content of 1-2 wt%.
The design principle of the invention is as follows:
according to the method, different metal atoms are dispersed on carbon nitride, then an organic carbon source is coated on a carbon nitride precursor loaded with metal, then the carbon nitride is decomposed through high-temperature treatment, and the metal atoms are transferred from the carbon nitride to a nitrogen-doped carbon carrier (obtained by carbonizing the organic carbon source), so that a high-entropy monoatomic material which is stably and uniformly dispersed on the nitrogen-doped carbon carrier is obtained. And mixing the high-entropy monoatomic catalyst with a small amount of binder, adding a proper amount of solvent, and uniformly coating the obtained slurry on a battery diaphragm to obtain the diaphragm modified by the high-entropy monoatomic catalyst.
The high-entropy monoatomic catalyst modified diaphragm has excellent mechanical stability and better electrolyte affinity, and can accelerate the transmission of lithium ions at a positive electrode/diaphragm reaction interface when applied to a lithium-sulfur battery. Meanwhile, the high-entropy monoatomic catalyst can adsorb lithium polysulfide and accelerate the kinetics of sulfur oxidation-reduction reaction, so that the shuttle effect is effectively inhibited, the utilization rate of active substances is improved, and the specific capacity and the cycling stability of the lithium-sulfur battery are improved.
The invention has the advantages and beneficial effects as follows:
1. the high-entropy single-atom catalyst modified diaphragm prepared by the method has excellent mechanical property and stability, and the phenomenon of powder falling off after bending and folding is avoided.
2. The high-entropy monoatomic catalyst modified diaphragm prepared by the method can greatly improve the wettability of electrolyte and accelerate the transmission of lithium ions at a positive electrode/diaphragm reaction interface.
3. The high-entropy monoatomic catalyst prepared by the invention can accelerate the oxidation-reduction reaction process of sulfur, inhibit the shuttle effect and enable the lithium-sulfur battery to have higher capacity and cycle stability.
4. The preparation method disclosed by the invention is simple in preparation process, wide in source of required raw materials, easy to regulate and control the content of each metal component, good in processability and beneficial to realizing large-scale production.
Description of the drawings:
fig. 1 is an electrochemical performance diagram of a lithium sulfur battery using a polypropylene separator (PP): (a) a first-turn charge-discharge curve at a current density of 1C; (b) Rate performance curves at 0.2C, 0.5C, 1C, 3C, 5C current densities.
Fig. 2 is a graph of electrochemical performance of a lithium sulfur battery using a nitrogen-doped carbon support material modified separator (cn@pp): (a) a first-turn charge-discharge curve at a current density of 1C; (b) Rate performance curves at 0.2C, 0.5C, 1C, 3C, 5C current densities.
FIG. 3 is a graph of electrochemical performance of a lithium sulfur battery using a cobalt single atom catalyst modified separator (Co-SAC/CN@PP): (a) a first-turn charge-discharge curve at a current density of 1C; (b) Rate performance curves at 0.2C, 0.5C, 1C, 3C, 5C current densities.
FIG. 4 is an X-ray diffraction pattern of a high entropy monoatomic catalyst (HESAC/CN).
FIG. 5 is a spherical electron microscope image of a high entropy monoatomic catalyst (HESAC/CN).
FIG. 6 is a photograph of (a) an optical photograph of a high entropy monoatomic catalyst modified membrane (HESAC/CN@PP) and (b) - (c) comparative measurements of electrolyte contact angles on different membranes. Wherein, (b) is a PP membrane, and (c) is a HESAC/CN@PP membrane.
FIG. 7 is a graph of electrochemical performance of a lithium sulfur battery using a high entropy single atom catalyst modified separator (HESAC/CN@PP): (a) a first-turn charge-discharge curve at a current density of 1C; (b) Rate performance curves at 0.2C, 0.5C, 1C, 3C, 5C current densities.
The specific embodiment is as follows:
in the specific implementation process, different soluble metal salts and carbon nitrogen compounds (such as melamine and other organic compounds) are mixed and subjected to heat treatment to obtain a precursor, and then metal atoms on the precursor are transferred to a nitrogen-doped carbon carrier through high-temperature argon treatment to obtain the high-entropy single-atom catalyst which can be used as a modification material of a diaphragm in a lithium-sulfur battery. The high-entropy monoatomic catalyst modified diaphragm prepared by the method greatly improves the wettability of the diaphragm to electrolyte, is used for accelerating the kinetics of the redox reaction of sulfur in a lithium-sulfur battery, inhibits the shuttle effect, and can accelerate the transmission of lithium ions at a positive electrode/diaphragm reaction interface, so that the lithium-sulfur battery has excellent cycle performance and rate capability.
The present invention will be described with reference to comparative examples and examples, but the present invention is not limited to the following examples.
Comparative example 1:
comparative example 1 is the use of a polypropylene separator (PP) in a lithium sulfur battery, the preparation method comprising:
preparing a carbon-sulfur positive electrode plate: sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the proportion of 8:1: adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material; mixing 70mg of sulfur-carbon positive electrode material, 20mg of carbon black and 10mg of polyvinylidene fluoride (PVDF) uniformly, adding 425mg of N-methyl pyrrolidone to obtain uniform slurry, coating the uniform slurry on the surface of a carbon-coated aluminum foil, vacuum drying at 60 ℃ and cutting into wafers with the diameter of 12mm to obtain a sulfur-carbon positive electrode plate, and weighing to obtain the sulfur-carbon positive electrode plate with the sulfur loading amount of 1.1mg/cm per unit area 2 ；
Use in lithium sulfur batteries: 2025 button cell was used for electrochemical performance testing of electrode materials. The sulfur-carbon positive electrode piece is taken as a positive electrode (diameter is 12 mm), the lithium piece (diameter is 16 mm) is taken as a negative electrode, and the polypropylene film (diameter is 19 mm) is taken as a diaphragm. The electrolyte is 1M lithium bis (trifluoromethylsulfonyl) imide dissolved in a 1, 3-dioxolane and ethylene glycol dimethyl ether mixed solution with a volume ratio of 1:1, and the additive is 2wt% anhydrous lithium nitrate. In discharge test, the potential interval is 1.7-2.8V (vs. Li/Li) + ). As shown in the figure1 (a), the lithium sulfur battery using the PP separator can only realize the first-turn discharge capacity of 311mAh/g at the current density of 1C and has larger polarization voltage. The second discharge plateau was not apparent, indicating that the severe shuttle effect resulted in low sulfur utilization. As shown in fig. 1 (b), specific capacities of the lithium sulfur battery using the PP separator at 0.2C, 0.5C, 1C, 3C, and 5C rates are 503mAh/g, 417mAh/g, 364mAh/g, 297mAh/g, and 257mAh/g, respectively, and the rate returns to 0.2C, and the specific capacity reaches 439mAh/g, and the specific capacities at the respective current densities are low.
Comparative example 2:
comparative example 2 is a preparation method of a nitrogen-doped carbon support material modified separator (cn@pp) and application thereof in a lithium sulfur battery, the preparation method comprising:
preparation of a nitrogen-doped carbon support material modified membrane: 9g of melamine are added to 150ml of aqueous hydrochloric acid (concentration 20% by weight) and stirred at 110℃until the liquid evaporates. And (3) placing the material obtained after the evaporation to dryness in a muffle furnace, heating to 550 ℃ at a heating rate of 5 ℃/min, and calcining for 2 hours to obtain the carbon nitride precursor material. After 2.3g of the carbon nitride precursor material and 0.7g of dopamine hydrochloride were stirred in a 3mol/L solution of tris (hydroxymethyl) aminomethane for 24 hours, centrifuged and vacuum-dried at 60 ℃, the obtained solid was placed in a tube furnace, heated to 900 ℃ at a heating rate of 3 ℃/min in an argon atmosphere, and calcined for 2 hours to obtain a nitrogen-doped carbon support material (CN) with a nitrogen doping amount of 10.35wt%. The coating slurry was obtained by uniformly mixing 90mg of CN and 10mg of polyvinylidene fluoride (PVDF) with 1g of N-methylpyrrolidone, and the nitrogen-doped carbon support modified membrane (CN@PP) was obtained by uniformly coating the slurry on the surface of a polypropylene film, and the thickness of the coating layer was about 50. Mu.m.
Preparing a carbon-sulfur positive electrode plate: sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the proportion of 8:1: adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material; mixing 70mg of sulfur-carbon positive electrode material, 20mg of carbon black and 10mg of polyvinylidene fluoride (PVDF) uniformly, adding 425mg of N-methyl pyrrolidone to obtain uniform slurry, coating the uniform slurry on the surface of a carbon-coated aluminum foil, vacuum-drying at 60 ℃ and cutting into wafers with the diameter of 12mm to prepare a sulfur-carbon positive electrode plate, and weighing to obtain sulfurThe sulfur loading per unit area of the carbon positive plate is 1.4mg/cm 2 ；
Use in lithium sulfur batteries: 2025 button cell was used for electrochemical performance testing of electrode materials. The sulfur-carbon positive electrode piece is taken as a positive electrode (diameter is 12 mm), the lithium piece (diameter is 16 mm) is taken as a negative electrode, and CN@PP (diameter is 19 mm) is taken as a diaphragm. The electrolyte is a mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether with the molar concentration of lM and the volume ratio of lithium bis (trifluoromethyl sulfonyl) imide to 1:1, and the additive is anhydrous lithium nitrate with the weight percentage of 2 percent. In discharge test, the potential interval is 1.7-2.8V (vs. Li/Li) + ). As shown in fig. 2 (a), the lithium sulfur battery using cn@pp separator can achieve a first-turn discharge capacity of 842mAh/g at a current density of 1C, which is improved compared with the unmodified separator, but the polarization voltage is still larger. The modified layer of the diaphragm plays a certain role in inhibiting the shuttling of lithium polysulfide. As shown in fig. 2 (b), specific capacities of the lithium sulfur battery using the cn@pp separator at 0.2C, 0.5C, 1C, 3C and 5C magnifications are 1065mAh/g, 977mAh/g, 895mAh/g, 724mAh/g and 482mAh/g respectively, and the magnifications can be returned to 0.2C specific capacity to 1042mAh/g, which indicates that the nitrogen-doped carbon material modified separator can improve the rate performance of the battery to a certain extent.
Comparative example 3:
comparative example 3 is a preparation method of cobalt monoatomic catalyst modified membrane (Co-SAC/CN@PP) and application thereof in a lithium sulfur battery, wherein the preparation method comprises the following steps:
preparation of cobalt monoatomic catalyst modified membrane: 9g melamine and 0.3g CoCl 2 ·6H 2 O is added into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirred at 110 ℃ until the liquid is evaporated to dryness, the material obtained after evaporation to dryness is placed in a muffle furnace, and the material is heated to 550 ℃ at a heating rate of 5 ℃/min and calcined for 2 hours to obtain the Co precursor material. After 2.3g of Co precursor material and 0.7g of dopamine hydrochloride were stirred in a 3mol/L solution of tris (hydroxymethyl) aminomethane for 24 hours, the mixture was centrifuged and dried under vacuum at 60℃to obtain a solid, which was placed in a tube furnace, heated to 900℃at a heating rate of 3℃per minute under an argon atmosphere, and calcined for 2 hours to obtain a cobalt monoatomic catalyst material (Co-SAC/CN). 90mg of Co-SAC/CN and 10mg of polyvinylidene fluoride (PVDF) and 1g of N-methyl pyrrolidone to obtain coating slurry, and uniformly coating the slurry on the surface of a polypropylene film to obtain the high-entropy single-atom catalyst modified diaphragm (Co-SAC/CN@PP), wherein the thickness of the coating layer is about 50 mu m.
Preparing a carbon-sulfur positive electrode plate: sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the proportion of 8:1: adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material; mixing 70mg of sulfur-carbon positive electrode material, 20mg of carbon black and 10mg of polyvinylidene fluoride (PVDF) uniformly, adding 425mg of N-methyl pyrrolidone to obtain uniform slurry, coating the uniform slurry on the surface of a carbon-coated aluminum foil, vacuum drying at 60 ℃ and cutting into wafers with the diameter of 12mm to obtain a sulfur-carbon positive electrode plate, and weighing to obtain the sulfur-carbon positive electrode plate with the sulfur loading amount of 1.4mg/cm per unit area 2 ；
Use in lithium sulfur batteries: 2025 button cell was used for electrochemical performance testing of electrode materials. The sulfur-carbon positive electrode piece is taken as a positive electrode (diameter is 12 mm), the lithium piece (diameter is 16 mm) is taken as a negative electrode, and Co-SAC/CN@PP (diameter is 19 mm) is taken as a diaphragm. The electrolyte is a mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether with the molar concentration of lM and the volume ratio of lithium bis (trifluoromethyl sulfonyl) imide to 1:1, and the additive is anhydrous lithium nitrate with the weight percentage of 2 percent. In discharge test, the potential interval is 1.7-2.8V (vs. Li/Li) + ). As shown in fig. 3 (a), the lithium-sulfur battery using the Co-SAC/cn@pp separator has a first-turn discharge capacity of 1030mAh/g at a current density of 1C, and the discharge capacity of the battery is further improved, and the polarization voltage is also reduced, because cobalt single atoms can adsorb soluble lithium polysulfide, and a certain catalytic effect is exerted on the oxidation-reduction reaction of sulfur. As shown in fig. 3 (b), the specific capacities of the lithium sulfur battery using the Co-SAC/cn@pp separator at the magnifications of 0.2C, 0.5C, 1C, 3C and 5C are 1207mAh/g, 1088mAh/g, 983mAh/g, 808mAh/g and 580mAh/g respectively, and the magnifications can reach 1133mAh/g after returning to the specific capacity of 0.2C, which indicates that the magnifications of the battery using the cobalt monoatomic catalyst to modify the separator are also improved.
Example 1:
example 1 is a preparation method of a high entropy single atom catalyst modified membrane (HESAC/CN@PP) and application thereof in a lithium sulfur battery, wherein the preparation method comprises the following steps:
preparation of high entropy monoatomic catalyst modified membrane: 9g of melamine and 0.3g of FeCl 3 ·6H 2 Adding O into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirring at 110 ℃ until the liquid is evaporated to dryness, placing the material obtained after evaporation to dryness into a muffle furnace, heating to 550 ℃ at a heating rate of 5 ℃/min, and calcining for 2 hours to obtain Fe precursor material; 9g melamine and 0.3g CoCl 2 ·6H 2 Adding O into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirring at 110 ℃ until the liquid is evaporated to dryness, placing the material obtained after evaporation to dryness into a muffle furnace, heating to 550 ℃ at a heating rate of 5 ℃/min, and calcining for 2 hours to obtain a Co precursor material; 9g of melamine and 0.3g of NiCl 2 ·6H 2 Adding O into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirring at 110 ℃ until the liquid is evaporated to dryness, placing the evaporated material into a muffle furnace, heating to 550 ℃ at a heating rate of 5 ℃/min, and calcining for 2 hours to obtain a Ni precursor material; 9g of melamine and 0.3g of CuCl 2 ·2H 2 Adding O into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirring at 110 ℃ until the liquid is evaporated to dryness, placing the evaporated material into a muffle furnace, heating to 550 ℃ at a heating rate of 5 ℃/min, and calcining for 2 hours to obtain a Cu precursor material; 9g melamine and 0.3g MnCl 2 ·4H 2 O is added into 150ml of hydrochloric acid aqueous solution (the concentration is 20wt%) and stirred at 110 ℃ until the liquid is evaporated to dryness, the material obtained after evaporation to dryness is placed into a muffle furnace, and the temperature is raised to 550 ℃ at a heating rate of 5 ℃/min, and the Mn precursor material is obtained after calcination for 2 hours. After 0.6g of Fe precursor material, 0.8g of Co precursor material, 0.3g of Ni precursor material, 0.3g of Cu precursor material and 0.3g of Mn precursor material are uniformly mixed, the mixture is stirred with 0.7g of dopamine hydrochloride in a 3mol/L tris-hydroxymethyl aminomethane solution for 24 hours, and then the mixture is centrifuged and dried under vacuum at 60 ℃, and the obtained high-entropy catalyst precursor is placed in a tube furnace, and is heated to 900 ℃ at a heating rate of 3 ℃/min in an argon atmosphere, and calcined for 2 hours to obtain the high-entropy monoatomic catalyst material (HESAC/CN). As shown in FIG. 4, by using X-ray diffraction to characterize the high-entropy monoatomic catalyst, it can be found that the material only shows characteristic peaks of carbon and no characteristic peaksThe presence of any peaks of metal and metal oxide confirm that no metal clusters or nanoparticles are formed. Further observations of the material using a spherical aberration correcting mirror, it can be seen from fig. 5 that the metals are all present in the form of single atoms and are uniformly distributed on the nitrogen doped carbon matrix with a total metal content of 4.23wt% and a nitrogen doping amount of 11.9wt%. A coating slurry was obtained by uniformly mixing 90mg HESAC/CN and 10mg polyvinylidene fluoride (PVDF) with 1g of N-methylpyrrolidone, the solid content in the slurry was 9.1wt%, and a high entropy single-atom catalyst modified membrane (HESAC/CN@PP) was obtained by uniformly coating the slurry on the surface of a polypropylene film, the thickness of the coating layer was about 50. Mu.m. As shown in fig. 6 (a), the high-entropy monoatomic catalyst modified membrane has excellent mechanical properties and stability, and does not have the phenomenon of powder falling after bending and folding. The affinity of HESAC/CN@PP composite membrane to electrolyte is detected through a contact angle test, and the result is shown in the figures 6 (b) - (c), compared with the unmodified PP membrane, the modification (HESAC/CN@PP) of the high-entropy monoatomic catalyst can effectively reduce the contact angle of the membrane to the electrolyte, so that the membrane has better electrolyte wettability, and is beneficial to the transmission of lithium ions at a positive electrode/membrane reaction interface.
Preparing a carbon-sulfur positive electrode plate: sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the proportion of 8:1: adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material; uniformly mixing 70mg of sulfur-carbon positive electrode material, 20mg of carbon black and 10mg of polyvinylidene fluoride (PVDF), adding 425mg of N-methyl pyrrolidone to obtain uniform slurry, coating the slurry on the surface of a carbon-coated aluminum foil, vacuum-drying at 60 ℃ and cutting into wafers with the diameter of 12mm to obtain a sulfur-carbon positive electrode plate, and weighing to obtain the sulfur-carbon positive electrode plate with the unit area sulfur loading of 1.0mg/cm 2 ；
Use in lithium sulfur batteries: 2025 button cell was used for electrochemical performance testing of electrode materials. The sulfur-carbon positive electrode piece is taken as a positive electrode (diameter is 12 mm), the lithium piece (diameter is 16 mm) is taken as a negative electrode, and HESAC/CN@PP (diameter is 19 mm) is taken as a diaphragm. The electrolyte is 1M bis (trifluoromethyl sulfonyl) imine lithium with molar concentration and is dissolved in a mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether with the volume ratio of 1:1, and the solution is addedThe additive was 2wt% anhydrous lithium nitrate. In discharge test, the potential interval is 1.7-2.8V (vs. Li/Li) + ). As shown in fig. 7 (a), the lithium-sulfur battery using the hecac/cn@pp separator has a first-turn discharge capacity of 1127mAh/g at a current density of 1C, the discharge capacity is greatly improved, and the polarization voltage is also obviously reduced, which indicates that the high-entropy monoatomic catalyst has a remarkable catalytic effect on the oxidation-reduction reaction of sulfur. Compared with the batteries of the PP diaphragm, the CN@PP diaphragm and the Co-SAC/CN@PP diaphragm, the battery of the HESAC/CN@PP diaphragm has the highest specific discharge capacity and the smallest polarization voltage. As shown in fig. 7 (b), the specific capacities of the lithium sulfur battery using the hecac/cn@pp separator at the magnifications of 0.2C, 0.5C, 1C, 3C and 5C are 1185mAh/g, 1111mAh/g, 1031mAh/g, 889mAh/g and 800mAh/g respectively, and the magnifications can still reach 1164mAh/g after returning to the specific capacity of 0.2C, which indicates that the battery using the high-entropy monoatomic catalyst to modify the separator has good rate performance, especially can still obtain high specific capacity at the high magnifications of 5C.
Therefore, based on the above examples and comparative examples, in order to further improve the catalytic efficiency of the metal monoatomic catalyst, the present invention provides a method for preparing a high-entropy monoatomic catalyst modified membrane, in which more kinds of metal elements are introduced into a monoatomic system, to obtain a high-entropy monoatomic catalytic material and use it as a membrane modification material. The high-entropy monoatomic catalytic material has rich active sites and synergistic effects among different active sites, can effectively inhibit shuttle effects, can greatly improve the redox reaction kinetics of sulfur, shows excellent electrochemical performance when being used in a lithium-sulfur battery, and can realize better cycle performance and rate performance when being applied in the lithium-sulfur battery. The preparation method is simple, the raw materials are cheap, the expansion production is facilitated, and the method has wide commercial application prospect.
Furthermore, the foregoing embodiments are illustrative of the present invention, and are not to be construed as limiting thereof. Any modifications and alterations should be seen as a result of the principles and techniques of this disclosure.
Claims (10)
1. The preparation method of the high-entropy monoatomic catalyst modified diaphragm is characterized by comprising the following steps of:
(1) Mixing five or more soluble metal salts with carbon nitrogen compound respectively, stirring and heating in hydrochloric acid solution until the liquid is evaporated to dryness, and heat-treating the evaporated mixture to obtain a precursor material for loading metal;
(2) Uniformly mixing the precursor material loaded with the metal, stirring the mixture with an organic carbon source in a buffer solution for 24 hours, centrifuging and drying the mixture to obtain a high-entropy catalyst precursor, and carrying out high-temperature treatment on the high-entropy catalyst precursor in an inert protective atmosphere to obtain a high-entropy monoatomic catalyst material;
(3) And mixing and grinding the high-entropy monoatomic catalyst material and the binder, adding a solvent to obtain uniform slurry, coating the slurry on the surface of the battery diaphragm, and drying to obtain the high-entropy monoatomic catalyst modified diaphragm.
2. The method for preparing the high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in the step (1), the soluble metal salt is a metal chloride or a metal nitrate of Fe, co, ni, cu, mn, cr, pt, pd element, and the carbon-nitrogen compound is one of melamine, urea, dicyandiamide and thiourea.
3. The method for preparing a high entropy monoatomic catalyst modified membrane according to claim 1, wherein in step (1), the heat treatment process is as follows: placing the mixture after being evaporated to dryness in a muffle furnace, heating to 500-550 ℃ at a heating rate of 5-10 ℃/min, and calcining for 2-4 hours.
4. The method for preparing the high-entropy single-atom catalyst modified membrane according to claim 1, wherein in the step (2), the organic carbon source is one of dopamine, dopamine hydrochloride, tannic acid, polyvinylpyrrolidone and glucose; the buffer solution is one of tris (hydroxymethyl) aminomethane, 4-hydroxyethyl piperazine ethane sulfonic acid, phosphate buffer solution and ammonia water-ammonium chloride buffer solution.
5. The method for preparing the high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in the step (2), the high-temperature treatment process is as follows: and (3) placing the high-entropy catalyst precursor in a tube furnace, heating to 800-1100 ℃ at a heating rate of 1-5 ℃/min under the protection of argon or nitrogen, and calcining for 2-4 hours.
6. The method for preparing a high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in the step (2), each metal atom of the high-entropy monoatomic catalyst is uniformly dispersed on a nitrogen-doped carbon matrix, and the total metal content is 1-8wt%; in the nitrogen-doped carbon matrix, the nitrogen doping amount is 7-12 wt%.
7. The method for preparing the high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in the step (3), the binder is one of polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose and polyacrylic acid; the solvent is one of N-methyl pyrrolidone and water.
8. The method for preparing the high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in the step (3), the mass ratio of the high-entropy monoatomic catalyst material to the binder is 9:1 to 4:1, the solid content in the slurry is 7-12 wt%.
9. The method for producing a high-entropy monoatomic catalyst modified membrane according to claim 1, wherein in step (3), the coating layer thickness of the high-entropy monoatomic catalyst modified membrane is 5 to 50. Mu.m.
10. Use of a high entropy monoatomic catalyst modified separator prepared by the method of any one of claims 1 to 9 in a lithium sulfur battery, wherein the preparation of the lithium sulfur battery comprises the steps of:
(1) Sulfur powder, multi-wall carbon nano tube and carbon black are mixed according to the following proportion (7-8): (2-1): adding the mixture into ethanol according to the mass ratio of 1, performing ultrasonic dispersion for 30-40 minutes, and drying at 60 ℃ to obtain a sulfur-carbon cathode material;
(2) Sulfur-carbon positive electrode material, carbon black and polyvinylidene fluoride are mixed according to the following proportion (7-8): (2-1): 1, after evenly mixing and grinding, adding N-methyl pyrrolidone to obtain even slurry, wherein the solid content in the slurry is 15-20wt%, coating the slurry on the surface of a carbon-coated aluminum foil, and cutting into wafers with the diameter of 12mm after vacuum drying at 60 ℃ to obtain a sulfur-carbon polar plate;
(3) The button cell is assembled in a glove box filled with argon, the anode is a sulfur carbon pole piece, the cathode is metallic lithium, the diaphragm is a high-entropy single-atom catalyst modified diaphragm, the electrolyte is 1M bis (trifluoromethylsulfonyl) imide lithium in molar concentration, the electrolyte is dissolved in a mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether in a volume ratio of 1:1, and the additive is lithium nitrate with a content of 1-2 wt%.
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