CN117894987A - Composite lithium-rich material and preparation method and application thereof - Google Patents
Composite lithium-rich material and preparation method and application thereof Download PDFInfo
- Publication number
- CN117894987A CN117894987A CN202311673657.XA CN202311673657A CN117894987A CN 117894987 A CN117894987 A CN 117894987A CN 202311673657 A CN202311673657 A CN 202311673657A CN 117894987 A CN117894987 A CN 117894987A
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- Prior art keywords
- lithium
- rich
- composite lithium
- rich material
- composite
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Links
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 361
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 355
- 239000000463 material Substances 0.000 title claims abstract description 204
- 239000002131 composite material Substances 0.000 title claims abstract description 153
- 238000002360 preparation method Methods 0.000 title claims abstract description 35
- 239000002245 particle Substances 0.000 claims abstract description 161
- 229920000049 Carbon (fiber) Polymers 0.000 claims abstract description 121
- 239000004917 carbon fiber Substances 0.000 claims abstract description 121
- 238000000034 method Methods 0.000 claims abstract description 48
- 239000011148 porous material Substances 0.000 claims description 78
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 48
- 239000003054 catalyst Substances 0.000 claims description 28
- 239000012018 catalyst precursor Substances 0.000 claims description 27
- 239000002808 molecular sieve Substances 0.000 claims description 25
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 25
- 229910052723 transition metal Inorganic materials 0.000 claims description 23
- 238000001179 sorption measurement Methods 0.000 claims description 19
- 229920005989 resin Polymers 0.000 claims description 18
- 239000011347 resin Substances 0.000 claims description 18
- 239000002134 carbon nanofiber Substances 0.000 claims description 17
- -1 transition metal salt Chemical class 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 239000002243 precursor Substances 0.000 claims description 14
- 238000002156 mixing Methods 0.000 claims description 13
- 239000002994 raw material Substances 0.000 claims description 12
- 238000007740 vapor deposition Methods 0.000 claims description 9
- 239000003513 alkali Substances 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 4
- 229910000385 transition metal sulfate Inorganic materials 0.000 claims description 3
- 229910002001 transition metal nitrate Inorganic materials 0.000 claims description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 39
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 39
- 230000008569 process Effects 0.000 abstract description 30
- 239000013078 crystal Substances 0.000 abstract description 10
- 239000000126 substance Substances 0.000 description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 24
- 239000007789 gas Substances 0.000 description 19
- 230000001502 supplementing effect Effects 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 14
- 229910052742 iron Inorganic materials 0.000 description 13
- 150000001875 compounds Chemical class 0.000 description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 10
- 239000010410 layer Substances 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 10
- 239000000843 powder Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 9
- 230000014759 maintenance of location Effects 0.000 description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 238000007599 discharging Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000007774 positive electrode material Substances 0.000 description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- 239000011888 foil Substances 0.000 description 6
- 239000008187 granular material Substances 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 150000003624 transition metals Chemical class 0.000 description 6
- 239000011800 void material Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 238000011534 incubation Methods 0.000 description 5
- 239000002344 surface layer Substances 0.000 description 5
- 229910001428 transition metal ion Inorganic materials 0.000 description 5
- 229910052720 vanadium Inorganic materials 0.000 description 5
- 238000005019 vapor deposition process Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
- 239000003463 adsorbent Substances 0.000 description 4
- 238000012512 characterization method Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000006258 conductive agent Substances 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 4
- 230000002427 irreversible effect Effects 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 230000000704 physical effect Effects 0.000 description 4
- 239000007784 solid electrolyte Substances 0.000 description 4
- 239000013589 supplement Substances 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 3
- 239000012159 carrier gas Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000005056 compaction Methods 0.000 description 3
- 230000008602 contraction Effects 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 3
- 229910052808 lithium carbonate Inorganic materials 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 241000894007 species Species 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229920001661 Chitosan Polymers 0.000 description 2
- 229910018871 CoO 2 Inorganic materials 0.000 description 2
- 229910018091 Li 2 S Inorganic materials 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000006183 anode active material Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 239000010431 corundum Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 150000002642 lithium compounds Chemical class 0.000 description 2
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 229910052573 porcelain Inorganic materials 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- OADJRHDTYUXHAR-UHFFFAOYSA-N 1,3-dioxolan-2-one;ethyl methyl carbonate Chemical compound O=C1OCCO1.CCOC(=O)OC OADJRHDTYUXHAR-UHFFFAOYSA-N 0.000 description 1
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 description 1
- 125000003184 C60 fullerene group Chemical group 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- 241000289669 Erinaceus europaeus Species 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 1
- 208000037656 Respiratory Sounds Diseases 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 229910001429 cobalt ion Inorganic materials 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- 229960000355 copper sulfate Drugs 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910000358 iron sulfate Inorganic materials 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 235000015110 jellies Nutrition 0.000 description 1
- 239000008274 jelly Substances 0.000 description 1
- 238000006138 lithiation reaction Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 229910001453 nickel ion Inorganic materials 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229940053662 nickel sulfate Drugs 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000011163 secondary particle Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000661 sodium alginate Substances 0.000 description 1
- 235000010413 sodium alginate Nutrition 0.000 description 1
- 229940005550 sodium alginate Drugs 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/26—Deposition of carbon only
-
- 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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- 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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The application relates to the technical field of lithium ion batteries and provides a composite lithium-rich material, a preparation method and application thereof. The composite lithium-rich material provided by the application comprises a three-dimensional frame formed by a plurality of carbon fibers, and lithium-rich particles are covered and isolated in the three-dimensional frame, so that on one hand, the capability of outwards transmitting lithium ions of the lithium-rich particles can be enhanced by utilizing the strong conductive capability of the three-dimensional frame, and on the other hand, the anisotropic expansion and shrinkage of the material crystal in the charge-discharge process of the composite lithium-rich material can be relieved, so that cracks generated by the composite lithium-rich material particles are reduced, and the composite lithium-rich material has higher structural stability.
Description
Technical Field
The application belongs to the technical field of lithium ion batteries, and particularly relates to a composite lithium-rich material, and a preparation method and application thereof.
Background
The lithium ion battery is used as a secondary battery and can be used for reversibly converting chemical energy and electric energy, and is an ideal carrier for human use and energy storage. Since the advent of lithium ion batteries, they have been widely used because of their long life, high energy density, and low maintenance costs. However, during primary charging, lithium ions are stored by the positive electrode to the negative electrode, accompanied by formation of a Solid Electrolyte (SEI) on the surface of the negative electrode. This process irreversibly consumes a large amount of active lithium, thereby reducing the first week coulombic efficiency, capacity, and energy density of the battery. The active lithium is supplemented, so that the application of the lithium supplementing technology not only improves the capacity of the lithium ion battery, but also can prolong the cycle life of the silicon-containing negative electrode battery. The reported ways of supplementing active lithium are mainly two major types of negative electrode lithium supplementing and positive electrode lithium supplementing.
Considering the high safety of practical operation and the suitability of the lithium ion battery with the existing battery production process, the lithium ion battery cathode has more industrial application prospect. The positive electrode lithium supplementing is to add a lithium-containing compound with high irreversible capacity into the positive electrode of a lithium ion battery, and is attracting attention because of the advantages of relatively stability, easy synthesis, low price, high lithium supplementing capability and the like.
At present, the lithium-rich material mainly comprises ternary lithium-rich compounds and binary lithium-rich compounds. However, the lithium-rich material itself has low conductivity and releases oxygen while lithium is being replenished by the first charge and discharge. On one hand, poor conductivity can affect the lithium ion transmission capability of the lithium-rich material, and the lithium supplementing capacity cannot be fully released; on the other hand, oxygen released during the lithium replenishment process increases the safety risk of the lithium battery.
Disclosure of Invention
The invention aims to provide a composite lithium-rich material, a preparation method and application thereof, and aims to solve the technical problem that the current lithium-rich material is low in conductivity.
In order to achieve the purposes of the application, the technical scheme adopted by the application is as follows:
in a first aspect, the present application provides a composite lithium-rich material comprising:
A plurality of carbon fibers forming a three-dimensional frame; the method comprises the steps of,
and the lithium-rich particles are distributed in the three-dimensional framework.
In a second aspect, the present application provides a method for preparing a composite lithium-rich material, comprising the steps of:
providing lithium-rich particles, a catalyst precursor and a carbon fiber raw material precursor;
mixing lithium-rich particles with a catalyst precursor to obtain a mixed material, and depositing a carbon fiber raw material precursor on the surface of the mixed material by adopting a vapor deposition method to catalyze and grow carbon fibers, so that the lithium-rich particles are distributed in a three-dimensional frame formed by a plurality of carbon fibers, thereby obtaining the composite lithium-rich material.
In a third aspect, the present application provides a positive electrode sheet, including a positive electrode current collector and a positive electrode active layer bonded to at least one surface of the positive electrode current collector, where the positive electrode active layer includes the composite lithium-rich material of the present application example and/or the composite lithium-rich material prepared by the preparation method of the composite lithium-rich material of the present application example.
In a fourth aspect, the present application provides a secondary battery comprising the positive electrode tab of the present application.
The composite lithium-rich material provided by the first aspect of the application comprises a plurality of carbon fibers and lithium-rich particles, wherein the carbon fibers form a three-dimensional framework, the lithium-rich particles are uniformly distributed in the three-dimensional framework, on one hand, the capability of the three-dimensional framework for transmitting lithium ions outwards by the lithium-rich particles can be enhanced by utilizing the strong electric conduction capability of the three-dimensional framework, on the other hand, the anisotropic expansion and shrinkage of material crystals in the charging and discharging process of the composite lithium-rich material can be relieved, so that cracks generated by the composite lithium-rich material particles are reduced, the composite lithium-rich material has higher structural stability, and on the other hand, the carbon fibers have higher stability and toughness, so that the composite lithium-rich material is endowed with higher stability and toughness, and the composite lithium-rich material is not easy to generate cracks due to stress concentration in the charging and discharging process; therefore, the composite lithium-rich material has higher electrochemical properties such as gram capacity, cycle performance, stability and the like.
According to the preparation method of the composite lithium-rich material, firstly, lithium-rich particles and a catalyst precursor are uniformly mixed, then carbon fibers are deposited on the outer surfaces of the lithium-rich particles through a vapor deposition method, and the catalyst precursor forms a catalyst for catalyzing the growth of the carbon fibers in the process; because the lithium-rich particles and the catalyst precursor are uniformly mixed, the lithium-rich particles can be uniformly distributed in a three-dimensional framework formed by a plurality of carbon fibers, and the composite lithium-rich material has the performance as the composite lithium-rich material. In addition, the preparation method of the composite lithium-rich material can ensure that the prepared composite lithium-rich material has stable structure and electrochemical performance, and is high in efficiency and low in production cost.
The positive electrode plate provided by the third aspect of the application, due to the fact that the positive electrode plate comprises the composite lithium-rich material, the composite lithium-rich material has high structural stability, capacity and safety performance, active lithium ions consumed by formation of an SEI film when a battery is charged for the first time can be provided, and accordingly high cycle stability, capacity and safety performance are provided for the positive electrode plate.
The secondary battery provided in the fourth aspect of the present application has high energy density and cycle performance, and is high in safety performance, because it contains the positive electrode sheet of the present application.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly introduce the drawings that are needed in the embodiments or the description of the prior art, it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a preparation process of a composite lithium-rich material provided in an embodiment of the present application;
FIG. 2 is a scanning electron micrograph of lithium-rich particles as provided in example 3 of the present application;
FIG. 3 is a scanning electron micrograph (magnification of 5000 times) of the composite lithium-rich material provided in example 3 of the present application;
fig. 4 is a scanning electron micrograph (magnification of 20000 times) of the composite lithium-rich material provided in example 3 of the present application.
Wherein, each reference sign in the figure:
10. lithium-rich particles, 20, porous materials, 30, a catalyst precursor, 40 and a three-dimensional framework;
41. carbon fiber.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved by the present application more clear, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
In this application, the term "and/or" describes an association relationship of an association object, which means that there may be three relationships, for example, a and/or B may mean: a alone, a and B together, and B alone. Wherein A, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship.
In the present application, "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
It should be understood that, in various embodiments of the present application, the sequence number of each process does not mean that the sequence of execution is sequential, and some or all of the steps may be executed in parallel or sequentially, where the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weights of the relevant components mentioned in the embodiments of the present application may refer not only to specific contents of the components, but also to the proportional relationship between the weights of the components, and thus, any ratio of the contents of the relevant components according to the embodiments of the present application may be enlarged or reduced within the scope disclosed in the embodiments of the present application. Specifically, the mass described in the specification of the examples of the present application may be a mass unit known in the chemical industry such as μ g, mg, g, kg.
The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated for distinguishing between objects such as substances from each other. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.
The term "VGCF" is an abbreviation of "vapor growth carbon fibers" and indicates vapor grown carbon fiber.
In the description of the embodiment of the present application, the SEI (solid electrolyte interface) film refers to a solid electrolyte interface film having the characteristics of a solid electrolyte, that is, a film formed by a passivation layer covering the surface of an electrode material formed by a reaction between the electrode material and an electrolyte at a solid-liquid interface during the first charge and discharge process of a liquid lithium ion battery.
A first aspect of embodiments of the present application provides a composite lithium-rich material, comprising:
a plurality of carbon fibers forming a three-dimensional frame; the method comprises the steps of,
and the lithium-rich particles are distributed in the three-dimensional framework.
The composite lithium-rich material provided by the first aspect of the embodiment of the application comprises a plurality of carbon fibers and lithium-rich particles, wherein the carbon fibers form a three-dimensional framework, the lithium-rich particles are uniformly distributed in the three-dimensional framework, on one hand, the capability of the three-dimensional framework for enhancing the outward lithium ion transmission capability of the lithium-rich particles can be utilized, on the other hand, the anisotropic expansion and shrinkage of material crystals in the charge and discharge process of the composite lithium-rich material can be relieved, so that cracks generated by the composite lithium-rich material particles are reduced, the composite lithium-rich material has higher structural stability, and on the other hand, the carbon fibers have higher stability and toughness, so that the composite lithium-rich material has higher stability and toughness, and is not easy to generate cracks due to stress concentration in the charge and discharge process; therefore, the composite lithium-rich material has higher electrochemical properties such as gram capacity, cycle performance, stability and the like.
It is understood that the lithium-rich particles include at least one of a lithium-rich positive electrode material and a lithium-supplementing material. The lithium-rich particles may be primary particles or secondary particles formed by aggregation of primary particles.
If the composite lithium-rich material is a lithium-rich positive electrode material, the lithium-rich particles are uniformly distributed in a three-dimensional framework formed by a plurality of carbon fibers, so that the composite lithium-rich material has higher structural stability and excellent conductivity, and the composite lithium-rich material has higher electrochemical properties such as gram capacity, cycle performance, safety, stability and the like. If the composite lithium-rich material is a lithium-supplementing material, the composite lithium-rich material has excellent lithium supplementing effect and higher structural stability due to the existence of a three-dimensional framework formed by carbon fibers, and can be used as a sacrificial agent in the first-round charging process to release all lithium ions as far as possible at one time so as to supplement irreversible lithium ions consumed by forming SEI films on the negative electrodes. Of course, the composite lithium-rich material can also comprise a lithium-rich positive electrode material and a lithium supplementing material, that is, the composite lithium-rich material contains abundant lithium ions and can supplement irreversible lithium ions consumed by forming an SEI film on a negative electrode, so that the abundance of lithium ions in a battery system is maintained, and the initial efficiency and the overall electrochemical performance of the battery are improved.
In some embodiments, the plurality of carbon fibers are interwoven to form a three-dimensional framework of a coil-like structure.
The extending directions of the adjacent carbon fibers are random, and the extending directions do not have preset paths and symmetry, so that the plurality of carbon fibers can form a three-dimensional framework of a coil-shaped structure through interweaving. Since the winding/interlacing between the carbon fibers is random, there is no symmetry in the density of the three-dimensional framework of the coil-like structure. It will be appreciated that there is a certain difference in the length of the carbon fibers, whereby the terminals of some of the carbon fibers constitute the surface layer of the coil-like structure, such that the surface layer of the coil-like structure has the morphological feature of "hedgehog", and in particular, the winding density of some of the carbon fibers is slightly lower or the terminals of some of the carbon fibers constitute the surface layer of the coil-like structure, such that the surface layer of the coil-like structure is in an uneven state, that is, the surface layer of the three-dimensional frame is in an uneven state.
Through keep apart the lithium-rich granule cage in three-dimensional frame, can make the three-dimensional frame fully absorb, weaken by compound lithium-rich material in charge and discharge in-process material crystal anisotropic expansion shrinkage's stress that releases, reduce compound lithium-rich material granule and produce the risk of crackle, can also further reduce the incomplete base number on compound lithium-rich material surface, from this, further improve compound lithium-rich material's structural stability, promote the cyclic storage performance of battery. In addition, the three-dimensional framework of the coil-shaped structure also has larger specific surface area, and can further improve the lithium ion transmission efficiency of the composite lithium-rich material.
In some embodiments, the three-dimensional framework of the coil-like structure has a plurality of voids, and at least a portion of the lithium-rich particles are contained within the voids of the three-dimensional framework.
It is understood that the coil-like structure is a structure formed by interweaving a plurality of carbon fibers, so the coil-like structure is a hollow structure, i.e. has voids, and the shape of the voids is not limited, and may include, but is not limited to, square, polygonal, circular or elliptical. The coil-like structure is not particularly limited in shape and may include a sphere, an irregular sphere, a spheroid, and the like.
The plurality of carbon fibers can be randomly wound and interwoven to form a three-dimensional framework with a coil-shaped structure, and the three-dimensional framework has gaps which can provide enough accommodating space for accommodating lithium-rich particles. In one possible embodiment, the size of the void matches the size of the lithium-rich particles, the lithium-rich particles being immobilized within the void; in yet another possible embodiment, the void provides a larger receiving space for receiving a plurality of lithium-rich particles such that the plurality of lithium-rich particles are immobilized within the void; in another possible embodiment, the space provides a space that is large enough for the lithium-rich particles to move within, and of course, the three-dimensional frame has a plurality of spaces, and the movement range of the lithium-rich particles is limited, which is equivalent to that the lithium-rich particles are still fixed in the three-dimensional frame.
In some embodiments, the voids range in size from 50nm to 500nm and the lithium-rich particles range in size from 100nm to 800nm.
Optionally, the particle size of the lithium-rich particles ranges from 200nm to 500nm; optionally, the particle size of the lithium-rich particles is in the range of 250nm to 300nm. Illustratively, the particle size of the lithium-rich particles may be 100nm, 200nm, 250nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, or within a range consisting of any of the above values. In the embodiments of the present application, the lithium-rich particles may be spherical or spheroid, and the particle size of the lithium-rich particles may be understood as the diameter of the lithium-rich particles.
It is understood that the size of the void refers to the diameter of the largest inscribed circle of the void projection.
Illustratively, the voids may have a size of 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, or within a range consisting of any of the above values.
The gap can form a transmission channel of lithium ions, so that the lithium ions can permeate into the electrolyte through the gap, the transmission rate of active ions in the composite lithium-rich material is effectively improved, and the electrical performance of the composite lithium-rich material is fully exerted. If the size of the gap is too small, the difficulty in removing lithium ions is increased to a certain extent, if the size of the gap is too large, lithium-rich particles easily pass through the gap, the effect of the three-dimensional framework formed by carbon fibers on the shielding and isolation of the lithium-rich particles is affected, and the uniformity of the distribution of the lithium-rich particles in the three-dimensional framework is also affected.
If the particle size of the lithium-rich particles is too large, the transmission path of lithium ions is larger, so that the transmission rate of the lithium ions is influenced; if the particle size of the lithium-rich particles is too small, the lithium-rich particles have obvious agglomeration effect, poor dispersibility and are not easy to fix in a three-dimensional framework formed by carbon fibers. In the particle size range provided by the embodiment of the application, the lithium-rich particles are good in dispersibility and have proper lithium ion diffusion rate, and the lithium-rich particles are uniformly distributed in the three-dimensional framework, so that the conductivity and the structural stability of the lithium-rich particles are improved.
In this application, the effect of space is used for providing the transfer passageway of lithium ion on the one hand, and on the other hand lies in fixed rich lithium granule, from this, the size in this application embodiment will space and rich lithium granule's particle diameter setting in above-mentioned within range for space and rich lithium granule's size assorted not only can restrict rich lithium granule and pass the carbon fiber and interweave the three-dimensional frame that forms, thereby improve the structural stability of compound rich lithium material, can also provide the passageway that is used for lithium ion transmission, give the higher gram capacity of compound rich lithium material.
In some embodiments, the carbon fibers comprise Vapor Grown Carbon Fibers (VGCF).
According to the embodiment of the application, the vapor phase growth carbon fiber (VGCF) is selected, so that lithium-rich particles are uniformly distributed on a three-dimensional framework formed by interweaving carbon fibers, the anisotropic expansion and shrinkage of material crystals of the composite lithium-rich material in the charge and discharge process can be effectively relieved, and cracks generated by the composite lithium-rich material particles are further reduced.
In some embodiments, the carbon fiber has a hollow tube structure.
The mesoporous pipeline structure can improve the elasticity of a three-dimensional frame formed by interweaving a plurality of carbon fibers, so that the three-dimensional frame can be used as a buffer layer to fully absorb and weaken stress released by the anisotropic expansion and contraction of material crystals of the composite lithium-rich material in the charge and discharge process, and the risk of cracking of the composite lithium-rich material particles is reduced. In addition, although the carbon fiber tube wall is contacted with the lithium-rich particles, the mesoporous tube structure can also absorb the gas released by the composite lithium-rich material in the charge and discharge process to a certain extent, so that the safety performance of the battery is further improved.
In some embodiments, the lithium-rich material further includes a catalyst distributed within the three-dimensional framework, the catalyst including a transition metal element-containing species. Exemplary transition metal element-containing species include one or more of elemental transition metals, transition metal sulfides, transition metal carbides, transition metal oxides. Wherein, the transition metal simple substance comprises but is not limited to iron simple substance, cobalt simple substance, nickel simple substance, copper simple substance and zinc simple substance.
The species containing the transition metal element can be used as a growth catalyst of carbon fibers, so that a three-dimensional framework is formed by a plurality of grown carbon fibers, lithium-rich particles are uniformly distributed in the three-dimensional framework, and the anisotropic expansion and shrinkage of material crystals of the composite lithium-rich material in the charge and discharge processes are further relieved, so that the structural stability of the composite lithium-rich material is improved.
In some embodiments, the catalyst comprises 0.1wt% to 5wt% of the lithium-rich particles. Illustratively, the mass fraction of catalyst to lithium-rich particles may be 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, or within a range comprised of any of the above values.
In some embodiments, the composite lithium-rich material further comprises a porous material distributed within the three-dimensional framework.
The porous structure of the porous material can absorb oxygen released by the composite lithium-rich material in the charge and discharge process, in particular, the porous material and the lithium-rich particles are distributed in a three-dimensional framework formed by interweaving a plurality of carbon fibers in a uniform form, so that the oxygen released by the lithium-rich particles in the charge and discharge process can be rapidly absorbed into the pore structure of the porous material by a plurality of adjacent porous materials, and the safety of the battery is effectively improved.
In some embodiments, a portion of the porous material is contained in the interstices of the coil structure.
The plurality of carbon fibers can be randomly wound and interwoven to form a coil-shaped structure, and the coil-shaped structure has gaps which can provide enough accommodating space for accommodating the porous material. In a possible implementation manner, the lithium-rich particles and the porous material are simultaneously present in the gaps, and at this time, the gas released by the lithium-rich particles in the first charge and discharge process can be quickly absorbed by the porous material, so that the safety performance of the battery is improved; in yet another possible embodiment, the porous material and the lithium-rich particles are present in adjacent voids, and at this time, the porous material can also rapidly absorb the gas released by the composite lithium-rich material during the charge and discharge processes.
In some embodiments, the mass ratio of the lithium-rich particles to the porous material to the carbon fibers is 100:0.1-10:0.1-20.
If the mass ratio of the porous material is too low, the oxygen released by the composite lithium-rich material in the charge and discharge process is difficult to be absorbed completely, and the safety performance of the battery may be affected; if the mass ratio of the porous material is too high, the porous material does not contribute lithium ions, which reduces the overall gram capacity of the composite lithium-rich material. By way of example, the mass ratio of the porous material may be a typical but non-limiting value of 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.
If the mass ratio of the carbon fibers is too low, on one hand, the conductivity of the composite lithium-rich material is improved to a limited extent, and on the other hand, the three-dimensional framework formed by interweaving the plurality of carbon fibers is difficult to cover the lithium-rich particles therein, so that the composite lithium-rich material is unfavorable for fully absorbing and weakening the stress released by the anisotropic expansion and contraction of the material crystals in the charge-discharge process, and the structural stability of the composite lithium-rich material is improved to a limited extent. If the mass ratio of the carbon fiber is too high, the carbon fiber does not contribute lithium ions, so that the overall gram capacity of the composite lithium-rich material is reduced, and the energy density of the battery is reduced. Illustratively, the mass ratio of carbon fibers may be typical, but not limiting, of 0.1, 0.5, 1, 3, 5, 7, 9, 10, 12, 14, 16, 18, 20, etc.
In some embodiments, the porous material has a particle size of 100nm to 800nm. Optionally, the particle size of the porous material is 200 nm-500 nm; alternatively, the particle size of the porous material is 250nm to 300nm.
If the particle size of the porous material is too small, the porous material possibly penetrates through a three-dimensional framework formed by interweaving carbon fibers, so that the porous material falls off, and the structural stability of the composite lithium-rich material is affected.
Illustratively, the particle size of the porous material may be 100nm, 200nm, 250nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, or within a range consisting of any of the above values.
In some embodiments, the porous material comprises a plurality of micropores, the micropores having a pore size < 2nm. The porous material comprises a plurality of micropores, so that oxygen released in the charging and discharging process of the composite lithium-rich material can enter micropore channels, thereby improving the gas diffusion efficiency and effectively increasing the utilization rate and the gas adsorption capacity of the porous material.
In some embodiments, the porous material comprises at least one of a type A molecular sieve, a type X molecular sieve, a type Y molecular sieve, a ZSM-5 molecular sieve, and a Beta molecular sieve. The multistage pore molecular sieves are stable in structure and rich in pore structure, and can improve the adsorption effect and the adsorption quantity of oxygen released in the charging and discharging process of the composite lithium-rich material.
In some embodiments, the carbon fibers have a diameter of 50nm to 300nm, a length of 1 μm to 20 μm, and a specific surface area of 1m 2 /g～300m 2 /g。
If the diameter of the carbon fiber is too small, the three-dimensional framework formed by interweaving the plurality of carbon fibers cannot isolate the lithium-rich particles from the porous material in the three-dimensional framework, if the diameter of the carbon fiber is too large, the conductivity of the carbon fiber is affected, and the conductivity of the composite lithium-rich material is limited. Illustratively, the carbon fibers may have diameters of 50nm, 80nm, 100nm, 120nm, 150nm, 170nm, 200nm, 250nm, 300nm, or within a range consisting of any of the above values.
If the length of the carbon fiber is too small, a three-dimensional frame cannot be formed; if the length of the carbon fiber is too long, the preparation difficulty and cost of the carbon fiber are increased, and the industrialized popularization of the lithium-rich material is not facilitated. Illustratively, the carbon fibers may have a length of 1 μm, 3 μm, 5 μm, 7 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, or within a range consisting of any of the above values.
The specific surface area refers to the total area of the mass of the substance. If the specific surface area of the carbon fiber is lower than the range, the transmission path of lithium ions is affected, so that the transmission rate of the lithium ions is reduced; if the specific surface area of the carbon fiber is higher than the above range, a three-dimensional frame is formedToo compact, the anisotropic expansion and contraction of the material crystal in the charge and discharge process of the composite lithium-rich material are difficult to effectively relieve, and the lattice volume expansion of the composite lithium-rich material cannot be restrained. Illustratively, the specific surface area of the carbon fiber may be 1m 2 /g、5m 2 /g、10m 2 /g、15m 2 /g、20m 2 /g、50m 2 /g、100m 2 /g、120m 2 /g、150m 2 /g、180m 2 /g、200m 2 /g、250m 2 /g、280m 2 /g、300m 2 /g or within the range of any of the values above.
In some embodiments, the lithium-rich particles have the formula L i1+x A y O z Wherein x is more than 0 and less than or equal to 1.2,1 and y is more than or equal to y<3，z>0, a includes at least one of Ni, fe, mn, co, cr, V, mo, ti, nb, zr, cu, mg.
It is understood that the lithium-rich particles include a lithium-rich positive electrode material or a lithium-supplementing material. Wherein the chemical formula of the lithium-rich particles corresponding to the lithium-rich positive electrode material is Li 1+x1 A y1 O z1 Wherein x1 is more than 0 and less than or equal to 1.2,1 and y1 is more than or equal to 2<3，z1>0, a includes at least one of Ni, fe, mn, co, cr, V, mo, ti, nb, zr, cu, mg. The lithium-rich particles of the type can be better matched with the carbon fiber and the porous material in the embodiment of the application, so that the composite lithium-rich material has more excellent performance.
Optionally, the lithium supplementing material comprises a binary lithium supplementing agent and/or a ternary lithium supplementing agent. The chemical general formula of the lithium-rich particles corresponding to the binary lithium supplementing agent is Li x2 M y2 Wherein M is at least one element in S, P, N, F, B, O, se, te, x2 is more than or equal to 1 and less than or equal to 5, and y2 is more than or equal to 0. Binary lithium supplements include, but are not limited to, li 3 N、Li 2 S、LiF、Li 3 P、Li 2 Se、Li 2 At least one of O.
Optionally, the chemical formula of the lithium-rich particles corresponding to the ternary lithium supplementing agent is Li a M b O c Wherein M is at least one element of Fe, ni, mn, cu, zn, co, cr, zr, sb, ti, V, mo, sn, a is more than or equal to 1 and less than or equal to 8, b is more than 0 and less than 7, and c is more than 0 and less than or equal to 7. In particular embodiments, lithium-richThe particles may be Li 5 FeO 4 、Li 6 MnO 4 、Li 6 CoO 4 、Li 6 ZnO 4 、Li 2 NiO 2 、Li 2 CuO 2 、Li 2 CoO 2 、Li 2 MnO 2 、Li 2 Ni 0.5 Mn 1.5 O 4 、Li 2 Ni d Cu (1-d) O 2 (0 < d < 1) and the like. The lithium-rich particles may also be Li 2 C 2 O 4 、Li 2 CO 3 Etc. The above-mentioned lithium-rich material may be undoped or doped modified, or may be subjected to surface coating, pre-lithiation treatment, or the like.
In some embodiments, the residual alkali content of the composite lithium-rich material is less than 5wt%. The surface of the lithium-rich compound generally contains a residual lithium compound having an alkaline property, and the specific form of the residual lithium compound mainly includes lithium carbonate, lithium hydroxide, lithium oxide, and the like, and may be referred to as residual alkali. The source of residual alkali mainly has two aspects, namely, the residual lithium (generally existing in the form of lithium oxide) in the preparation process adsorbs carbon dioxide and water in the air to form lithium hydroxide and lithium carbonate; on the other hand, lithium-rich compounds are exposed to air to form lithium carbonate. Excessive residual alkali content can bring a plurality of negative effects to the electrochemical performance of the lithium-rich material, such as influencing the coating of slurry, easily forming jelly shape in the homogenizing process, increasing irreversible capacity loss and deteriorating the cycle performance.
In the embodiment of the application, since the lithium-rich particles are distributed in the three-dimensional framework formed by interweaving the carbon fibers, namely, the lithium-rich particles can be covered and isolated in the three-dimensional framework, the protection effect is achieved, the reaction of water, carbon dioxide and the lithium-rich particles in the air can be avoided to a certain extent, and the residual alkali number of the composite lithium-rich material is further reduced.
In some embodiments, the composite lithium-rich material has a tap density of 0.6g/cm 3 ～2.5g/cm 3 . Exemplary, tap density may be 0.6g/m 3 、1g/m 3 、1.2g/m 3 、1.5g/m 3 、1.7g/m 3 、2g/m 3 、2.5g/m 3 Or within a range consisting of any of the above values.
Tap density refers to the mass per unit volume measured after the powder in the container is tapped under specified conditions, in g/cm 3 And (3) measuring by adopting a special tap density instrument. Since the volume of a lithium ion battery is limited, a higher tap density means a higher mass of active material per unit volume, the battery exhibits a higher volumetric capacity.
In the embodiment of the application, the lithium-rich particles are uniformly distributed in the three-dimensional framework formed by interweaving the carbon fibers, so that the composite lithium-rich material has proper tap density, and the anisotropic expansion and shrinkage of the material crystal in the charging and discharging process of the lithium-rich particles are effectively relieved, so that the generation of cracks of the lithium-rich particles is reduced, and the energy density of the battery is further improved.
A second aspect of the embodiments of the present application provides a method for preparing a composite lithium-rich material, including the following steps:
step S10, providing lithium-rich particles, a catalyst precursor and a carbon fiber raw material precursor according to the composite lithium-rich material provided in the first aspect of the embodiment of the application;
And step S20, mixing the lithium-rich particles with a catalyst precursor to obtain a mixed material, and depositing a carbon fiber raw material precursor on the surface of the mixed material by adopting a vapor deposition method to catalyze and grow carbon fibers, so that the lithium-rich particles are distributed in a three-dimensional frame formed by a plurality of carbon fibers, and a composite lithium-rich material is obtained.
According to the preparation method of the lithium-rich material, provided by the second aspect of the embodiment of the application, firstly, lithium-rich particles and a catalyst precursor are uniformly mixed, then carbon fibers are deposited on the outer surfaces of the lithium-rich particles through a vapor deposition method, and the catalyst precursor forms a catalyst for catalyzing the growth of the carbon fibers in the process; because the lithium-rich particles and the catalyst precursor are uniformly mixed, the lithium-rich particles can be uniformly distributed in a three-dimensional framework formed by a plurality of carbon fibers, and the composite lithium-rich material has the performance as the composite lithium-rich material. In addition, the preparation method of the composite lithium-rich material can ensure that the prepared composite lithium-rich material has stable structure and electrochemical performance, and is high in efficiency and low in production cost.
In some embodiments, in step S10, the composite lithium-rich material includes a lithium-rich positive electrode material or a lithium-supplementing material. Wherein the chemical formula of the lithium-rich particles corresponding to the lithium-rich positive electrode material is Li 1+x1 A y1 O z1 Wherein x1 is more than 0 and less than or equal to 1.2,1 and y1 is more than or equal to 2<3，z1>0, a includes at least one of Ni, fe, mn, co, cr, V, mo, ti, nb, zr, cu, mg. The preparation method of the lithium-rich particles is not limited, and can be prepared by methods well known in the art.
Optionally, the lithium supplementing material comprises a binary lithium supplementing agent and/or a ternary lithium supplementing agent. The chemical general formula of the lithium-rich particles corresponding to the binary lithium supplementing agent is Li x2 M y2 Wherein M is at least one element in O, S, se, te, N, P, x2 is more than or equal to 1 and less than or equal to 2, and y2 is more than or equal to 1 and less than or equal to 3. Binary lithium supplements include, but are not limited to, li 3 N、Li 2 S、LiF、Li 3 P、Li 2 Se、Li 2 At least one of O.
Optionally, the chemical formula of the lithium-rich particles corresponding to the ternary lithium supplementing agent is Li a M b O c Wherein M is at least one element of Fe, ni, mn, cu, zn, co, cr, zr, sb, ti, V, mo, sn, a is more than or equal to 1 and less than or equal to 8, b is more than 0 and less than 7, and c is more than 0 and less than or equal to 7. In particular embodiments, the lithium-rich particles may be Li 5 FeO 4 、Li 6 MnO 4 、Li 6 CoO 4 、Li 6 ZnO 4 、Li 2 NiO 2 、Li 2 CuO 2 、Li 2 CoO 2 、Li 2 MnO 2 、Li 2 Ni 0.5 Mn 1.5 O 4 、Li 2 Ni d Cu (1-d) O 2 (0 < d < 1) and the like. The lithium-rich particles may also be Li 2 C 2 O 4 、Li 2 CO 3 Etc.
In some embodiments, in step S10, the catalyst precursor comprises an adsorption resin and a transition metal salt supported on the adsorption resin, the transition metal salt comprising at least one of a transition metal sulfate, a transition metal nitrate, and a transition metal hydrochloride.
The adsorption resin is used for loading transition metal salt, and in the vapor deposition process, the adsorption resin is cracked into gas, and the loaded transition metal ions can form transition metal simple substances which can be used as a growth catalyst of carbon fibers.
In some embodiments, the adsorbent resin comprises a macroporous adsorbent resin. Exemplary macroporous adsorbent resins include, but are not limited to, one or more of the types D3520, D4006, D4020, AB-8, H103, D101.
In the vapor deposition process, the macroporous adsorption resin is gradually gasified and cracked, transition metal ions loaded by the macroporous adsorption resin can form transition metal simple substances, and the transition metal simple substances can be uniformly mixed with the lithium-rich particles due to uniform mixing of the lithium-rich particles and the catalyst precursors, and can also serve as a growth catalyst of carbon fibers, so that the lithium-rich particles can be uniformly distributed in a three-dimensional framework formed by interweaving the carbon fibers.
In some embodiments, the transition metal ions contained in the transition metal salt include, but are not limited to, iron ions, cobalt ions, nickel ions, copper ions, zinc ions.
Exemplary transition metal sulfates include at least one of iron sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zinc sulfate.
In some embodiments, the catalyst precursor is prepared as follows:
and (3) placing the adsorption resin in a solution containing transition metal salt, standing for 1-100 h, filtering, washing and drying to obtain the catalyst precursor.
Illustratively, the concentration of the transition metal salt-containing solution is from 0.001M to 10M.
Illustratively, the mass to volume ratio of the adsorbent resin to the solution containing the transition metal salt is from 1:100 to 1000, the mass units are grams and the volume units are milliliters.
In some embodiments, in step S10, the carbon fiber feedstock precursor includes a low hydrocarbon. Illustratively, the carbon fiber feedstock precursor includes methane, ethane,At least one of ethylene, acetylene, propane and propylene. The carbon fiber raw material precursors can obtain the precursor with the diameter of 50 nm-300 nm, the length of 1 mu m-20 mu m and the specific surface area of 1m in the vapor deposition process 2 /g～300m 2 VGCF/g.
In some embodiments, in step S10, the composite lithium-rich material provided according to the first aspect of the embodiments of the present application further includes a porous material.
In some embodiments, the porous material comprises at least one of a type A molecular sieve, a type X molecular sieve, a type Y molecular sieve, a ZSM-5 molecular sieve, and a Beta molecular sieve. The multistage pore molecular sieves are stable in structure and rich in pore structure, and can improve the adsorption effect and the adsorption quantity of oxygen released in the charging and discharging process of the composite lithium-rich material.
In some embodiments, step S20 may further be:
mixing lithium-rich particles, a porous material and a catalyst precursor to obtain a mixed material, and depositing the carbon fiber raw material precursor on the surface of the mixed material by adopting a vapor deposition method to catalyze and grow carbon fibers, so that the lithium-rich particles and the porous material are distributed in a three-dimensional framework formed by interweaving a plurality of carbon fibers to obtain the composite lithium-rich material.
During vapor deposition, the catalyst precursor is used as a catalyst for catalyzing the growth of carbon fibers; because lithium-rich particles, porous material and catalyst precursor mix evenly, so lithium-rich particles, porous material and catalyst are also in the state of evenly mixing, from this, lithium-rich particles, porous material can evenly distributed in the three-dimensional frame that is interweaved by many carbon fiber, effectively prepares and has the performance that this application composite lithium-rich material had as above-mentioned.
In some embodiments, in step S20, the vapor deposition process is performed at a temperature of 700 ℃ to 1200 ℃ and a holding time of 0.5h to 24h. Under the condition, the carbon fiber raw material precursor can be deposited on the outer surface of the lithium-rich particles, and the grown carbon fibers are interwoven to form a three-dimensional framework and isolate the lithium-rich particles from the three-dimensional framework. By way of example, the temperature may be, but is not limited to, values typical of 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1100 ℃, 1200 ℃, and the like. By way of example, the incubation time may be typical but non-limiting values of 0.5h, 1h, 2h, 5h, 7h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.
In some embodiments, in step S20, a carbon fiber raw material precursor is introduced into the reaction chamber with a carrier gas. Illustratively, the carrier gas includes at least one of nitrogen, argon, hydrogen, helium. Wherein the volume ratio of the carrier gas to the carbon fiber raw material precursor is 100:1-1:100.
A schematic diagram of a preparation process of the lithium-rich material in the embodiment of the application is shown in FIG. 1. The raw materials of the composite lithium-rich material include lithium-rich particles 10, porous material 20, and catalyst precursor 30. Initially, the lithium-rich particles 10, the porous material 20 and the catalyst precursor 30 are uniformly mixed, and then, in the vapor deposition process, the adsorption resin contained in the catalyst precursor 30 is gradually cracked and gasified, and the transition metal ions carried by the adsorption resin are converted into the transition metal simple substance serving as a catalyst for the growth of the carbon fibers 41. The carbon fibers 41 are grown to extend outwardly from the outer surface of the catalyst, and the catalyst may simultaneously catalyze the growth of a plurality of carbon fibers 41, whereby one end of each carbon fiber 41 is combined with a small amount of catalyst, which may be understood as the initial growth end of the carbon fiber 41 is combined with a small amount of catalyst. The plurality of carbon fibers 41 are interwoven during the growth and elongation to form the three-dimensional frame 40.
Since the lithium-rich particles 10, the porous material 20, and the catalyst precursor 30 are in a uniformly mixed state before vapor deposition is performed, the lithium-rich particles 10, the porous material 20 can be uniformly distributed in the three-dimensional frame 40 formed by interlacing the plurality of carbon fibers 41.
A third aspect of the embodiments of the present application provides a positive electrode sheet, including a positive electrode current collector and a positive electrode active layer bonded on at least one surface of the positive electrode current collector, where the positive electrode active layer includes the composite lithium-rich material of the embodiments of the present application and/or the composite lithium-rich material prepared by the preparation method of the composite lithium-rich material of the embodiments of the present application.
The positive electrode plate provided in the third aspect of the embodiment of the application, due to the inclusion of the composite lithium-rich material, has higher structural stability, capacity and safety performance, and can provide active lithium ions consumed by formation of an SEI film when a battery is charged for the first time, so that higher cycle stability, capacity and safety performance are provided for the positive electrode plate.
In one embodiment, the mass content of the above composite lithium-rich material contained in the positive electrode active layer may be 80wt% to 95wt%.
The positive electrode active layer includes a binder and a conductive agent in addition to the composite lithium-rich material, wherein the binder may be a common electrode binder such as one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan, and chitosan derivatives. In the present embodiment, the conductive agent may be a conventional conductive agent, such as one or more including graphite, carbon black, acetylene black, graphene, carbon fiber, C60, and carbon nanotube.
In some embodiments, the positive electrode current collector includes, but is not limited to, at least one of aluminum foil, carbon coated aluminum foil, iron foil, tin foil, zinc foil, nickel foil, titanium foil, manganese foil.
In some embodiments, the preparation process of the positive electrode sheet may be: mixing an anode active material, a conductive agent and a binder to obtain electrode slurry, coating the electrode slurry on an anode current collector, and preparing an anode plate through the steps of drying, rolling, die cutting and the like, wherein the anode active material comprises the composite lithium-rich material.
A fourth aspect of the embodiments provides a secondary battery comprising the positive electrode tab of the embodiments of the present application.
The secondary battery provided in the fourth aspect of the embodiment of the present application has high energy density and cycle performance, and also has high safety performance, because it contains the positive electrode sheet of the present application.
The composite lithium-rich material, the preparation method and the application thereof and the like are exemplified by a plurality of specific examples.
Composite lithium-rich material and preparation method thereof are as follows:
example 1
A composite lithium-rich material comprises lithium-rich particles (chemical formula is Li) with a mass ratio of 100:5:0.5:20 2 NiO 2 Diameter of 0.25 μm), porous material (ZSM-5 molecular sieve, particle size of 0.25 μm), catalyst (elemental iron) and VGCF. Specifically, a plurality of carbon fibers are interwoven to form a three-dimensional frame; the lithium-rich particles and the porous material are distributed in the gaps of the three-dimensional framework, and the catalyst is distributed on the framework of the three-dimensional framework.
The preparation method of the composite lithium-rich material comprises the following steps:
s1, placing macroporous adsorption resin D3520 in ferric chloride solution with the concentration of 2M, standing for 96 hours, filtering, washing and drying to obtain macroporous adsorption resin loaded with transition metal ions, and marking the macroporous adsorption resin as a catalyst precursor;
and S2, uniformly mixing the lithium-rich particles, the porous material and the catalyst precursor prepared in the step S1, placing the mixture into a corundum porcelain boat, placing the corundum porcelain boat in the middle of a tube furnace for vapor deposition, introducing methane and argon in a volume ratio of 2:1, heating to 1200 ℃, and preserving heat for 24 hours, so that the lithium-rich particles and the porous material are distributed in a three-dimensional frame formed by interweaving a plurality of carbon fibers, and thus the composite lithium-rich material is obtained.
Example 2
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:5:0.5:16, except that the porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) was used in the same manner as in example 1.
The preparation method of the lithium-rich material is different from that of the embodiment 1 in that: the incubation time in step S2 was 18h, and the procedure was the same as in example 1.
Example 3
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:5:0.5:10, except that the porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) was used in the same manner as in example 1.
The preparation method of the lithium-rich material is different from that of the embodiment 1 in that: the incubation time in step S2 was 10h, and the procedure was the same as in example 1.
Example 4
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:5:0.5:3, except that the porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) was used in the same manner as in example 1.
The preparation method of the composite lithium-rich material is different from that of the embodiment 1 in that: the incubation time in step S2 was 0.5h, otherwise the same as in example 1.
Example 5
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:5:0.5:0.1, except that the diameter was 0.25 μm), porous material (ZSM-5 molecular sieve, particle size of 0.25 μm), catalyst (elemental iron) was the same as in example 1.
The preparation method of the lithium-rich material is different from that of the embodiment 1 in that: the incubation time in step S2 was 10min, and the procedure was the same as in example 1.
Example 6
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 3 in that: the porous material was not contained, and the other was the same as in example 3.
Example 7
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:8:0.5:10, except that the mass ratio was the same as in example 3.
Example 8
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:10:0.5:10, except that the porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) was used in the same manner as in example 3.
Example 9
The embodiment provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material, differing from example 1 in that: lithium-rich particles (chemical formula is Li) 2 NiO 2 The mass ratio of catalyst (elemental iron) to VGCF was 100:0.1:0.5:10, except that the porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) was used in the same manner as in example 3.
Comparative example 1
The present comparative example provides a composite lithium-rich material comprising only lithium-rich particles (formula Li 2 NiO 2 ) The diameter of the lithium-rich particles was 0.25 μm.
Comparative example 2
The comparative example provides a composite lithium-rich material and a preparation method thereof.
A composite lithium-rich material comprises lithium-rich particles (chemical formula is Li) with a mass ratio of 100:5:20 2 NiO 2 Diameter of 0.25 μm), porous material (ZSM-5 molecular sieve, particle size of 0.25 μm) and VGCF; the length, diameter and specific surface area of the carbon fiber were the same as in example 1.
The preparation method of the composite lithium-rich material comprises the following steps:
mixing the lithium-rich particles, the porous material and the carbon fiber according to the proportion, and uniformly mixing by adopting a ball mill to obtain the composite lithium-rich material.
Lithium ion battery examples:
the lithium-rich materials provided in examples 1 to 9 and the composite lithium-rich materials provided in comparative examples 1 to 2 were assembled into a positive electrode and a lithium ion battery, respectively, according to the following methods:
Positive electrode: under the same conditions, according to (lithium-rich material): superP-Li: mixing PVDF, namely mixing the PVDF, the NMP and the NMP in a mass ratio of 95:2:3, uniformly mixing the materials by taking N-methyl pyrrolidone (NMP) as a solvent to prepare slurry, uniformly coating the slurry on the surface of an aluminum foil, rolling the aluminum foil to a certain thickness, and vacuum drying the aluminum foil at 110 ℃ for 12 hours to prepare the positive electrode plate; the lithium-rich materials are the composite lithium-rich materials provided in examples 1 to 9 and the composite lithium-rich materials provided in comparative examples, respectively.
A counter electrode: lithium metal sheet.
Electrolyte solution: liPF with electrolyte of 1mol/L 6 Ethylene carbonate methyl ethyl carbonate (volume ratio) =1:1 solution.
A diaphragm: a polypropylene microporous membrane.
And (3) assembling a lithium ion battery: the assembling sequence of the lithium metal sheet, the diaphragm, the electrolyte and the positive electrode sheet is assembled into the button type lithium ion battery in an inert atmosphere glove box. Batteries containing the composite lithium-rich material provided in examples 1 to 9 were respectively referred to as examples S1 to S9, and batteries containing the composite lithium-rich material provided in comparative examples 1 to 2 were referred to as comparative examples DS1 to DS2.
Performance detection
(1) Characterization of physical Properties
The lithium-rich particles used in example 1 (formula Li 2 NiO 2 ) Scanning Electron Microscope (SEM) analysis was performed and the results are shown in fig. 2.
The composite lithium-rich material prepared in example 1 was subjected to Scanning Electron Microscope (SEM), and the results are shown in fig. 3 to 4.
As can be seen from fig. 2, the lithium-rich particles used in the examples of the present application are spherical in shape and have substantially uniform particle diameters. As can be seen from fig. 3 to 4, the plurality of carbon fibers are interwoven to form a three-dimensional framework, and the length of the carbon fibers is larger than the diameter of the lithium-rich particles, so that the morphology of the composite lithium-rich material presents a coil-shaped structure, and the three-dimensional framework of the coil-shaped structure covers the lithium-rich particles and the porous material.
The composite lithium-rich materials provided in examples 1 to 9 and comparative examples 1 to 2 were subjected to physical property characterization tests, respectively. Physical property characterization test results of the lithium-rich material are shown in table 1 below.
(2) Powder resistivity test
And (3) loading a certain mass of powder sample (1-2 g) into a measuring jig, loading the jig into a pre-compaction instrument, starting the pre-compaction instrument for compaction for 15 seconds, loading the jig back into powder resistivity instrument starting software to start testing, automatically collecting the resistivity of the instrument, and demoulding by using a mould withdrawing device after the testing is finished.
(3) Gas production test
And (3) carrying out normal-temperature formation on the battery at the temperature of 25 ℃ at the multiplying power of 0.055 ℃, wherein the formation cut-off voltage is 2.0-4.15V, and detecting the gas production amount after the formation of the battery by adopting a battery gas production testing device so as to evaluate the gas production phenomenon of the battery.
(4) Electrochemical performance test
The electrochemical properties of lithium secondary batteries each composed of examples S1 to S9 and comparative examples DS1 to DS2 were tested.
Capacity retention test: after the formation of the battery is finished, the charging and discharging voltage window is controlled at 2.0-4.0V at the normal temperature of 25 ℃, the battery is charged at 1C (cut-off current is 0.025C), the 1C is discharged, and the cycle is 100 circles. After 100 cycles, capacity retention calculation formula = 100 cycles discharge capacity/first cycle charge capacity 100%.
The results of the related electrochemical performance test of the lithium secondary battery are shown in table 2 below.
Table 1 physical Property characterization test results of lithium rich materials
From the results in table 1, it can be seen that the powder resistivity of the composite lithium-rich materials prepared in examples 1 to 9 is far smaller than that of comparative examples 1 to 2, and the gas production rate of the composite lithium-rich materials prepared in examples 1 to 9 is smaller than that of comparative examples 1 to 2, so that it is demonstrated that the conductivity of the composite lithium-rich materials can be effectively improved after the three-dimensional conductive frames formed by interweaving the lithium-rich particles and the porous materials are covered by the three-dimensional conductive frames formed by interweaving the plurality of carbon fibers, and the powder resistivity of the composite lithium-rich materials can be further reduced, and the gas production rate of the porous materials can be effectively reduced. It can be seen from examples 1 to 5 that as the mass ratio of carbon fiber increases, the powder resistivity decreases and increases, the powder resistivity of example 2 decreases to 0.53 Ω·cm, and the powder resistivity of example 1 increases due to the thickening of the amorphous carbon layer of the VGCF outer layer which is unfavorable for electric conduction after the growth time is prolonged. The gas production of examples 4 and 5 is greater than that of examples 1-3 because the fiber diameter and length are too small to form a three-dimensional framework sufficient to uniformly disperse the lithium-rich particles and porous material therein, and even a portion of the material may have fallen off during the formation of the three-dimensional framework. It can be seen from examples 3, 6-9 that as the mass of the porous material increases, the gas production gradually decreases, especially as low as 1.4mL/g for example 8.
Table 2 electrochemical performance test results of lithium secondary battery
As can be seen from the results of table 2, the secondary batteries containing the composite lithium-rich material prepared in the present example application had higher primary charge capacity and 100-cycle capacity retention than the comparative examples. In comparative example DS2, although porous materials and carbon fibers were used as well, it was difficult to achieve uniform distribution of lithium-rich particles, porous materials and carbon fibers, and even if the carbon fibers formed a three-dimensional framework, the lithium-rich particles and porous materials could freely go in and out of the framework, the mixed state was extremely unstable, the overall conductivity could not be effectively improved, the effective absorption of produced gas could not be promoted, and accordingly poorer electrochemical performance was exhibited.
The performance of the embodiment S3 is optimal, the initial charge capacity is up to 162.7mAh/g, and the capacity retention rate of 100 circles is up to 96.6%. Since no porous material was added in example 6 compared to example 3, which resulted in an increase in gas production during the test, which affected the cycling stability of example S6, the 100-turn capacity retention was greatly reduced, but the presence of an appropriate amount of carbon fiber still resulted in a higher initial charge capacity level for example S6. Although the powder resistivity and gas yield of example 2 were comparable to those of example 3, the carbon fiber mass ratio of example 2 was too large, so that the initial charge capacity of example S2 was reduced to 156.3mAh/g, and correspondingly the capacity retention rate of 100 turns was also reduced. Although the gas production was smaller in examples S7 and S8, the porous material was too high in proportion, resulting in the first charge capacities of examples S7 and S8 being reduced to 160.2 and 158.3mAh/g, respectively, and the 100-turn capacity retention rates being reduced to 95.7% and 95.3%, respectively. Examples S4, S5 and S9 were degraded due to the too small ratio of carbon fiber or porous material in examples S4, S5 and S9. The porous material is too little, which is unfavorable for absorbing the produced gas, and further greatly reduces the capacity retention rate of 100 circles. The carbon fiber is too few, which is unfavorable for forming a good conductive network, and the lithium-rich particles and the porous material are difficult to uniformly and stably distribute in the three-dimensional framework, so that the primary charging capacity and the capacity retention rate of 100 circles are reduced.
The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but is intended to cover any and all modifications, equivalents, and alternatives falling within the spirit and principles of the present application.
Claims (12)
1. A composite lithium-rich material, comprising:
a plurality of carbon fibers forming a three-dimensional framework; the method comprises the steps of,
lithium-rich particles distributed in the three-dimensional framework.
2. The composite lithium-rich material of claim 1, wherein the plurality of carbon fibers are interwoven to form a three-dimensional framework of a coil-like structure.
3. The composite lithium-rich material of claim 2, wherein the three-dimensional framework of the coil-like structure has a plurality of voids, at least a portion of the lithium-rich particles being contained within the voids of the three-dimensional framework.
4. The composite lithium-rich material of claim 3, wherein the voids have a size ranging from 50nm to 500nm and the lithium-rich particles have a particle size ranging from 100nm to 800nm.
5. The composite lithium-rich material of claim 1, wherein the carbon fibers comprise vapor grown carbon fibers; and/or
The carbon fiber is of a hollow pipeline structure; and/or
The composite lithium-rich material further includes a catalyst distributed within the three-dimensional framework, the catalyst including a transition metal element-containing species.
6. The composite lithium-rich material of any one of claims 1 to 5, further comprising a porous material distributed within the three-dimensional framework.
7. The composite lithium-rich material of claim 6, wherein a portion of the porous material is contained within interstices of the coil structure; and/or
The mass ratio of the lithium-rich particles to the porous material to the carbon fiber is 100:0.1-10:0.1-20; and/or
The particle size of the porous material is 100 nm-800 nm; and/or
The porous material comprises at least one of an A-type molecular sieve, an X-type molecular sieve, a Y-type molecular sieve, a ZSM-5 molecular sieve and a Beta molecular sieve.
8. According to any one of claims 1 to 5The composite lithium-rich material of the present invention is characterized in that the carbon fiber has a diameter of 50nm to 300nm, a length of 1 μm to 20 μm, and a specific surface area of 1m 2 /g～300m 2 /g; and/or
The residual alkali content of the composite lithium-rich material is less than 5wt%; and/or
The tap density of the composite lithium-rich material is 0.6g/cm 3 ～2.5g/cm 3 。
9. The preparation method of the composite lithium-rich material is characterized by comprising the following steps of:
providing lithium-rich particles, a catalyst precursor and a carbon fiber raw material precursor;
mixing the lithium-rich particles with the catalyst precursor to obtain a mixed material, and depositing the carbon fiber raw material precursor on the surface of the mixed material by adopting a vapor deposition method to catalyze and grow carbon fibers, so that the lithium-rich particles are distributed in a three-dimensional frame formed by a plurality of carbon fibers to obtain the composite lithium-rich material according to any one of claims 1 to 8.
10. The method of preparing a composite lithium-rich material according to claim 9, wherein the catalyst precursor comprises an adsorption resin and a transition metal salt supported on the adsorption resin, the transition metal salt comprising at least one of a transition metal sulfate, a transition metal nitrate, and a transition metal hydrochloride.
11. A positive electrode sheet comprising a positive electrode current collector and a positive electrode active layer bonded to at least one surface of the positive electrode current collector, wherein the positive electrode active layer comprises the composite lithium-rich material according to any one of claims 1 to 8 and/or the composite lithium-rich material produced by the method for producing a composite lithium-rich material according to any one of claims 9 to 10.
12. A secondary battery comprising the positive electrode tab of claim 11.
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