CN117043992A - Electrode composition - Google Patents
Electrode composition Download PDFInfo
- Publication number
- CN117043992A CN117043992A CN202280023460.9A CN202280023460A CN117043992A CN 117043992 A CN117043992 A CN 117043992A CN 202280023460 A CN202280023460 A CN 202280023460A CN 117043992 A CN117043992 A CN 117043992A
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- Prior art keywords
- electrode
- vdf
- forming composition
- polymer
- weight
- Prior art date
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- 239000000203 mixture Substances 0.000 title claims abstract description 136
- 229920000642 polymer Polymers 0.000 claims abstract description 93
- 238000000034 method Methods 0.000 claims abstract description 36
- 239000011263 electroactive material Substances 0.000 claims abstract description 29
- 239000000178 monomer Substances 0.000 claims abstract description 16
- 125000000524 functional group Chemical group 0.000 claims abstract description 11
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 9
- 150000002148 esters Chemical class 0.000 claims abstract description 9
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 claims abstract description 8
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 claims description 76
- 150000001875 compounds Chemical class 0.000 claims description 34
- 229910052751 metal Inorganic materials 0.000 claims description 34
- 239000002184 metal Substances 0.000 claims description 34
- 239000000758 substrate Substances 0.000 claims description 16
- 229910052717 sulfur Inorganic materials 0.000 claims description 15
- 239000007787 solid Substances 0.000 claims description 14
- 239000003999 initiator Substances 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 11
- 230000008018 melting Effects 0.000 claims description 11
- 238000006116 polymerization reaction Methods 0.000 claims description 11
- 239000003638 chemical reducing agent Substances 0.000 claims description 10
- 150000003839 salts Chemical group 0.000 claims description 9
- 229910013716 LiNi Inorganic materials 0.000 claims description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 8
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- 239000011593 sulfur Substances 0.000 claims description 8
- 229910052723 transition metal Inorganic materials 0.000 claims description 8
- 150000003624 transition metals Chemical group 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 7
- 150000002739 metals Chemical class 0.000 claims description 7
- 229910052720 vanadium Inorganic materials 0.000 claims description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- 229910021645 metal ion Inorganic materials 0.000 claims description 6
- 150000001340 alkali metals Chemical group 0.000 claims description 5
- -1 ammonium ions Chemical group 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 5
- 239000007800 oxidant agent Substances 0.000 claims description 5
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
- 229910052798 chalcogen Inorganic materials 0.000 claims description 4
- 150000001787 chalcogens Chemical group 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 4
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 3
- 125000003118 aryl group Chemical group 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- INRFMNKGJCROAZ-UHFFFAOYSA-N 2-hydroxy-2-sulfinylacetic acid Chemical compound OC(=O)C(O)=S=O INRFMNKGJCROAZ-UHFFFAOYSA-N 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- QXNVGIXVLWOKEQ-UHFFFAOYSA-N Disodium Chemical class [Na][Na] QXNVGIXVLWOKEQ-UHFFFAOYSA-N 0.000 claims description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 2
- 229910010707 LiFePO 4 Inorganic materials 0.000 claims description 2
- 229910019142 PO4 Inorganic materials 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 125000000753 cycloalkyl group Chemical group 0.000 claims description 2
- 239000000839 emulsion Substances 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 2
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical class 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 2
- 239000010452 phosphate Substances 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 125000000626 sulfinic acid group Chemical group 0.000 claims 2
- 150000004770 chalcogenides Chemical class 0.000 claims 1
- BUUPQKDIAURBJP-UHFFFAOYSA-N sulfinic acid Chemical group OS=O BUUPQKDIAURBJP-UHFFFAOYSA-N 0.000 claims 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 16
- 239000002904 solvent Substances 0.000 description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 10
- 229920001577 copolymer Polymers 0.000 description 10
- 150000003254 radicals Chemical class 0.000 description 10
- 239000004094 surface-active agent Substances 0.000 description 10
- 238000002360 preparation method Methods 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- 239000006258 conductive agent Substances 0.000 description 7
- 239000011572 manganese Substances 0.000 description 7
- 238000005481 NMR spectroscopy Methods 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 239000002033 PVDF binder Substances 0.000 description 6
- 238000007720 emulsion polymerization reaction Methods 0.000 description 6
- 229920001519 homopolymer Polymers 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 239000003575 carbonaceous material Substances 0.000 description 5
- 238000005266 casting Methods 0.000 description 5
- 125000003709 fluoroalkyl group Chemical group 0.000 description 5
- 239000012966 redox initiator Substances 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 4
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 description 4
- 239000002041 carbon nanotube Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 239000004615 ingredient Substances 0.000 description 4
- 229910001416 lithium ion Inorganic materials 0.000 description 4
- 238000007639 printing Methods 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 239000002210 silicon-based material Substances 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 229910010710 LiFePO Inorganic materials 0.000 description 3
- 229910011322 LiNi0.6Mn0.2Co0.2O2 Inorganic materials 0.000 description 3
- 229910002995 LiNi0.8Co0.15Al0.05O2 Inorganic materials 0.000 description 3
- 229910015965 LiNi0.8Mn0.1Co0.1O2 Inorganic materials 0.000 description 3
- 239000011149 active material Substances 0.000 description 3
- 229910001413 alkali metal ion Inorganic materials 0.000 description 3
- XQJHRCVXRAJIDY-UHFFFAOYSA-N aminophosphine Chemical class PN XQJHRCVXRAJIDY-UHFFFAOYSA-N 0.000 description 3
- 239000006229 carbon black Substances 0.000 description 3
- 239000012986 chain transfer agent Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 125000001153 fluoro group Chemical group F* 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 125000004430 oxygen atom Chemical group O* 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 238000013112 stability test Methods 0.000 description 3
- CIHOLLKRGTVIJN-UHFFFAOYSA-N tert‐butyl hydroperoxide Chemical compound CC(C)(C)OO CIHOLLKRGTVIJN-UHFFFAOYSA-N 0.000 description 3
- MIZLGWKEZAPEFJ-UHFFFAOYSA-N 1,1,2-trifluoroethene Chemical group FC=C(F)F MIZLGWKEZAPEFJ-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 229910052493 LiFePO4 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910001420 alkaline earth metal ion Inorganic materials 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000003490 calendering Methods 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- UUAGAQFQZIEFAH-UHFFFAOYSA-N chlorotrifluoroethylene Chemical group FC(F)=C(F)Cl UUAGAQFQZIEFAH-UHFFFAOYSA-N 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
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- 230000007613 environmental effect Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical compound FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 2
- 229910021389 graphene Inorganic materials 0.000 description 2
- HCDGVLDPFQMKDK-UHFFFAOYSA-N hexafluoropropylene Chemical group FC(F)=C(F)C(F)(F)F HCDGVLDPFQMKDK-UHFFFAOYSA-N 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 150000002466 imines Chemical class 0.000 description 2
- 238000009830 intercalation Methods 0.000 description 2
- 150000002576 ketones Chemical class 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 150000001451 organic peroxides Chemical class 0.000 description 2
- 229910000064 phosphane Inorganic materials 0.000 description 2
- 150000004714 phosphonium salts Chemical class 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 2
- KDGNCLDCOVTOCS-UHFFFAOYSA-N (2-methylpropan-2-yl)oxy propan-2-yl carbonate Chemical compound CC(C)OC(=O)OOC(C)(C)C KDGNCLDCOVTOCS-UHFFFAOYSA-N 0.000 description 1
- RQHGZNBWBKINOY-PLNGDYQASA-N (z)-4-tert-butylperoxy-4-oxobut-2-enoic acid Chemical compound CC(C)(C)OOC(=O)\C=C/C(O)=O RQHGZNBWBKINOY-PLNGDYQASA-N 0.000 description 1
- AVQQQNCBBIEMEU-UHFFFAOYSA-N 1,1,3,3-tetramethylurea Chemical compound CN(C)C(=O)N(C)C AVQQQNCBBIEMEU-UHFFFAOYSA-N 0.000 description 1
- HSLFISVKRDQEBY-UHFFFAOYSA-N 1,1-bis(tert-butylperoxy)cyclohexane Chemical compound CC(C)(C)OOC1(OOC(C)(C)C)CCCCC1 HSLFISVKRDQEBY-UHFFFAOYSA-N 0.000 description 1
- BEQKKZICTDFVMG-UHFFFAOYSA-N 1,2,3,4,6-pentaoxepane-5,7-dione Chemical compound O=C1OOOOC(=O)O1 BEQKKZICTDFVMG-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- MXXFMIQVWPMONH-UHFFFAOYSA-N 1-fluoro-2-(2-fluoro-2-methoxyethenoxy)-1-methoxyethene Chemical compound FC(=COC=C(F)OC)OC MXXFMIQVWPMONH-UHFFFAOYSA-N 0.000 description 1
- GOAHRBQLKIZLKG-UHFFFAOYSA-N 1-tert-butylperoxybutane Chemical compound CCCCOOC(C)(C)C GOAHRBQLKIZLKG-UHFFFAOYSA-N 0.000 description 1
- HFNSTEOEZJBXIF-UHFFFAOYSA-N 2,2,4,5-tetrafluoro-1,3-dioxole Chemical compound FC1=C(F)OC(F)(F)O1 HFNSTEOEZJBXIF-UHFFFAOYSA-N 0.000 description 1
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical compound C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 description 1
- PFHOSZAOXCYAGJ-UHFFFAOYSA-N 2-[(2-cyano-4-methoxy-4-methylpentan-2-yl)diazenyl]-4-methoxy-2,4-dimethylpentanenitrile Chemical compound COC(C)(C)CC(C)(C#N)N=NC(C)(C#N)CC(C)(C)OC PFHOSZAOXCYAGJ-UHFFFAOYSA-N 0.000 description 1
- WYGWHHGCAGTUCH-UHFFFAOYSA-N 2-[(2-cyano-4-methylpentan-2-yl)diazenyl]-2,4-dimethylpentanenitrile Chemical compound CC(C)CC(C)(C#N)N=NC(C)(C#N)CC(C)C WYGWHHGCAGTUCH-UHFFFAOYSA-N 0.000 description 1
- LIZVXGBYTGTTTI-UHFFFAOYSA-N 2-[(4-methylphenyl)sulfonylamino]-2-phenylacetic acid Chemical compound C1=CC(C)=CC=C1S(=O)(=O)NC(C(O)=O)C1=CC=CC=C1 LIZVXGBYTGTTTI-UHFFFAOYSA-N 0.000 description 1
- JJRDRFZYKKFYMO-UHFFFAOYSA-N 2-methyl-2-(2-methylbutan-2-ylperoxy)butane Chemical compound CCC(C)(C)OOC(C)(C)CC JJRDRFZYKKFYMO-UHFFFAOYSA-N 0.000 description 1
- FRIBMENBGGCKPD-UHFFFAOYSA-N 3-(2,3-dimethoxyphenyl)prop-2-enal Chemical compound COC1=CC=CC(C=CC=O)=C1OC FRIBMENBGGCKPD-UHFFFAOYSA-N 0.000 description 1
- MKTOIPPVFPJEQO-UHFFFAOYSA-N 4-(3-carboxypropanoylperoxy)-4-oxobutanoic acid Chemical compound OC(=O)CCC(=O)OOC(=O)CCC(O)=O MKTOIPPVFPJEQO-UHFFFAOYSA-N 0.000 description 1
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 description 1
- ILCXNGLYOOUGLK-UHFFFAOYSA-N CC(=O)C1(S(O)(=O)=O)CCCCC1 Chemical compound CC(=O)C1(S(O)(=O)=O)CCCCC1 ILCXNGLYOOUGLK-UHFFFAOYSA-N 0.000 description 1
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
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- 229910018122 Li 3-x M Inorganic materials 0.000 description 1
- 229910015118 LiMO Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910012748 LiNi0.5Mn0.3Co0.2O2 Inorganic materials 0.000 description 1
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- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- BZLVMXJERCGZMT-UHFFFAOYSA-N Methyl tert-butyl ether Chemical compound COC(C)(C)C BZLVMXJERCGZMT-UHFFFAOYSA-N 0.000 description 1
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- 238000012565 NMR experiment Methods 0.000 description 1
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- JEAIVVDKUUARLF-UHFFFAOYSA-N acetyloxycarbonylperoxycarbonyl acetate Chemical compound CC(=O)OC(=O)OOC(=O)OC(C)=O JEAIVVDKUUARLF-UHFFFAOYSA-N 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 150000008051 alkyl sulfates Chemical class 0.000 description 1
- 229940045714 alkyl sulfonate alkylating agent Drugs 0.000 description 1
- 150000008052 alkyl sulfonates Chemical class 0.000 description 1
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium peroxydisulfate Substances [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 1
- VAZSKTXWXKYQJF-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)OOS([O-])=O VAZSKTXWXKYQJF-UHFFFAOYSA-N 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
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- YOALFLHFSFEMLP-UHFFFAOYSA-N azane;2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoic acid Chemical compound [NH4+].[O-]C(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F YOALFLHFSFEMLP-UHFFFAOYSA-N 0.000 description 1
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- 230000015572 biosynthetic process Effects 0.000 description 1
- UXXXZMDJQLPQPH-UHFFFAOYSA-N bis(2-methylpropyl) carbonate Chemical compound CC(C)COC(=O)OCC(C)C UXXXZMDJQLPQPH-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- KOPOQZFJUQMUML-UHFFFAOYSA-N chlorosilane Chemical class Cl[SiH3] KOPOQZFJUQMUML-UHFFFAOYSA-N 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- BLCKNMAZFRMCJJ-UHFFFAOYSA-N cyclohexyl cyclohexyloxycarbonyloxy carbonate Chemical compound C1CCCCC1OC(=O)OOC(=O)OC1CCCCC1 BLCKNMAZFRMCJJ-UHFFFAOYSA-N 0.000 description 1
- CSCPPACGZOOCGX-WFGJKAKNSA-N deuterated acetone Substances [2H]C([2H])([2H])C(=O)C([2H])([2H])[2H] CSCPPACGZOOCGX-WFGJKAKNSA-N 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 description 1
- JLNSPUHKOIYHEZ-UHFFFAOYSA-L disodium 2-hydroxy-2-oxo-1-sulfinylethanolate Chemical compound C(=O)(C(=S=O)[O-])O.C(=O)(C(=S=O)[O-])O.[Na+].[Na+] JLNSPUHKOIYHEZ-UHFFFAOYSA-L 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- CWINGZLCRSDKCL-UHFFFAOYSA-N ethoxycarbonyloxy ethyl carbonate Chemical compound CCOC(=O)OOC(=O)OCC CWINGZLCRSDKCL-UHFFFAOYSA-N 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 125000004428 fluoroalkoxy group Chemical group 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 239000004811 fluoropolymer Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- GNOIPBMMFNIUFM-UHFFFAOYSA-N hexamethylphosphoric triamide Chemical compound CN(C)P(=O)(N(C)C)N(C)C GNOIPBMMFNIUFM-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 125000003010 ionic group Chemical group 0.000 description 1
- 235000015110 jellies Nutrition 0.000 description 1
- 239000008274 jelly Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- SRSFOMHQIATOFV-UHFFFAOYSA-N octanoyl octaneperoxoate Chemical compound CCCCCCCC(=O)OOC(=O)CCCCCCC SRSFOMHQIATOFV-UHFFFAOYSA-N 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 125000005634 peroxydicarbonate group Chemical group 0.000 description 1
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 description 1
- 150000003002 phosphanes Chemical class 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007717 redox polymerization reaction Methods 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 239000012763 reinforcing filler Substances 0.000 description 1
- FZHAPNGMFPVSLP-UHFFFAOYSA-N silanamine Chemical class [SiH3]N FZHAPNGMFPVSLP-UHFFFAOYSA-N 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 125000000542 sulfonic acid group Chemical group 0.000 description 1
- KQYLUTYUZIVHND-UHFFFAOYSA-N tert-butyl 2,2-dimethyloctaneperoxoate Chemical compound CCCCCCC(C)(C)C(=O)OOC(C)(C)C KQYLUTYUZIVHND-UHFFFAOYSA-N 0.000 description 1
- OPQYOFWUFGEMRZ-UHFFFAOYSA-N tert-butyl 2,2-dimethylpropaneperoxoate Chemical compound CC(C)(C)OOC(=O)C(C)(C)C OPQYOFWUFGEMRZ-UHFFFAOYSA-N 0.000 description 1
- SWAXTRYEYUTSAP-UHFFFAOYSA-N tert-butyl ethaneperoxoate Chemical compound CC(=O)OOC(C)(C)C SWAXTRYEYUTSAP-UHFFFAOYSA-N 0.000 description 1
- 125000000999 tert-butyl group Chemical group [H]C([H])([H])C(*)(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- DZLFLBLQUQXARW-UHFFFAOYSA-N tetrabutylammonium Chemical compound CCCC[N+](CCCC)(CCCC)CCCC DZLFLBLQUQXARW-UHFFFAOYSA-N 0.000 description 1
- BJQWBACJIAKDTJ-UHFFFAOYSA-N tetrabutylphosphanium Chemical compound CCCC[P+](CCCC)(CCCC)CCCC BJQWBACJIAKDTJ-UHFFFAOYSA-N 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- CZDYPVPMEAXLPK-UHFFFAOYSA-N tetramethylsilane Chemical compound C[Si](C)(C)C CZDYPVPMEAXLPK-UHFFFAOYSA-N 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- CYRMSUTZVYGINF-UHFFFAOYSA-N trichlorofluoromethane Chemical compound FC(Cl)(Cl)Cl CYRMSUTZVYGINF-UHFFFAOYSA-N 0.000 description 1
- 229940029284 trichlorofluoromethane Drugs 0.000 description 1
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 1
- WVLBCYQITXONBZ-UHFFFAOYSA-N trimethyl phosphate Chemical compound COP(=O)(OC)OC WVLBCYQITXONBZ-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The present application relates to an electrode forming composition comprising an electroactive material and a VDF-based polymer comprising at least 70% by moles of recurring units derived from VDF, less than 0.9% by moles of recurring units derived from monomers comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester or mixtures thereof, has a TM between 130 ℃ and 180 ℃ and contains less than 700 mmoles/kg of chain-end-CF 2 H and-CF 2 CH 3 . The composition has good adhesion and is physically stable over time.The application also relates to the use of the electrode-forming composition in a method for manufacturing an electrode, the electrode and an electrochemical device, such as a secondary battery, comprising the electrode.
Description
Technical Field
The present application claims priority from provisional application number 63/164063 filed to the united states patent office at 22, 3, 2021 and patent application 21171892.9 filed to the european patent office at 5, 2021, the entire contents of each of these applications are incorporated herein by reference for all purposes.
The present invention relates to an electrode-forming composition, use of the electrode-forming composition in a method for manufacturing an electrode, the electrode, and an electrochemical device such as a secondary battery including the electrode.
Background
Electrochemical devices such as secondary batteries typically include a positive electrode, a negative electrode, a separator, and an electrolyte.
Electrodes for secondary batteries are generally produced by applying a composition for forming an electrode to a metal substrate, also referred to as a "current collector", for example, by casting, printing or roll coating. Electrode-forming compositions are typically formed by mixing a binder with a powdered electroactive material and optionally other ingredients such as solvents, conductivity-enhancing and/or viscosity-controlling materials. The binder is a key component of the electrode because it has the effect of ensuring good adhesion to the current collector and to the electroactive compound, thereby allowing the electroactive material to transport electrons as desired. Current commercial batteries typically use graphite as the electroactive compound in the anode and a mixed oxide containing lithium as the electroactive compound in the cathode. The electrode-forming composition is typically applied to a current collector and dried to remove any solvent. The resulting sheet is typically calendered or otherwise mechanically treated and rolled. Individual electrodes are then cut from the sheet.
Fluoropolymers are known in the art as suitable binders for use in the manufacture of electrodes for use in electrochemical devices such as secondary batteries.
In the related art, vinylidene fluoride Polymer (PVDF) has been used as an electrode binder in secondary batteries. Typical PVDF homopolymers have poor adhesion to metals. To overcome this problem, VDF-based copolymers have been proposed which contain, in addition to the repeat units derived from VDF, a small amount of repeat units derived from a comonomer bearing polar groups. As an example, it has been demonstrated in WO 2008/129041 that the inclusion of a small amount of repeating units derived from acrylic monomers improves the adhesion of VDF-based polymers to metals.
On the other hand, it has been observed that in some cases VDF copolymers bearing polar groups such as ionic groups (carboxyl, sulfonic, sulfinic, phosphonic), carbonyl (aldehyde, ketone, ester), -SH groups or hydroxyl groups, when used as binders in certain electrode-forming compositions, may result in the composition becoming a solid elastic "gel-like" material that cannot be spread and applied onto a current collector using conventional methods and equipment commonly used in the industry for this purpose (e.g. casting, printing or roll coating).
Current equipment for preparing electrodes requires that the electrode-forming composition be spreadable or extrudable as a viscous fluid. Thus, the electrode-forming composition in a cured form cannot be used with such devices. Although smaller amounts of solvents (which are generally desirable for environmental and cost reasons) and including LiFePO are used 4 Appears to have an effect on more frequently causing the composition to cure, but this "curing" effect is observed in a variety of active materials and solvents.
In some cases, when the electrode-forming composition is prepared, the "curing" of the composition occurs immediately. In other cases, a slow development of "curing" over time was observed, starting with a sharp increase in the viscosity of the electrode-forming composition over time. In some cases, even if the composition does not become a solid jelly, the increase in viscosity thereof makes it impossible to process the electrode-forming composition with conventional equipment. This is also a problem because the electrode-forming composition should be stable enough to be stored for at least 7 days during the electrode manufacturing process, while maintaining its physical properties.
Thus, there is a need for electrode forming compositions that do not cure, maintain a stable viscosity over time, and have good adhesion to metals.
The present invention meets this need by providing a novel electrode-forming composition comprising a polymer binder based on a selected VDF-based polymer that has no or a reduced number of polar groups while also having a small amount of-CF 2 H and-CF 2 CH 3 Chain ends. Such electrode-forming compositions surprisingly have good adhesion and are physically stable over time in a variety of conditions.
Disclosure of Invention
The present invention relates to an electrode-forming composition comprising:
(a) One or more VDF-based polymers, wherein:
(i) The VDF-based polymer comprises at least 70% by mole of repeating units derived from vinylidene fluoride (VDF) based on the total amount of repeating units of the polymer;
(ii) The VDF-based polymer comprises between 0.9% by moles Ji Xiao of recurring units based on the total amount of recurring units of the polymer, these recurring units comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof;
(iii) The VDF-based polymer has a melting temperature Tm comprised between 130 ℃ and 180 DEG C
(iv) The VDF-based polymer has a chain end-CF of less than 70 mmoles/kg as measured by NMR 2 H and-CF 2 CH 3 Total number of (2)
(b) One or more electroactive materials.
In another aspect, the present invention relates to a method for manufacturing an electrode using the electrode-forming composition as described above, the method comprising:
(i) Providing a metal substrate having at least one surface;
(ii) Providing an electrode-forming composition as defined above;
(iii) Applying the composition provided in step (ii) to at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate coated on at least one surface with the composition;
(iv) Drying the assembly provided in step (iii).
In another aspect, the invention relates to an electrode obtainable from such a method.
In another aspect, the present invention relates to an electrochemical device comprising the electrode.
Detailed Description
As described above, the present invention relates to an electrode-forming composition comprising a VDF-based polymer and an electroactive material.
By "VDF-based polymer" is meant a polymer or copolymer comprising a majority of repeat units derived from 1, vinylidene fluoride (or VDF). VDF-based polymers suitable for use in the present invention comprise at least 70%, preferably at least 80%, more preferably at least 90%, most preferably at least 94% by mole of recurring units derived from VDF. All percentages are based on the total amount of repeating units in the polymer. Particularly preferred are homopolymers of VDF.
The VDF-based polymers and copolymers used in the present invention must have a relatively small amount of polar functional groups. More specifically, VDF-based polymers and copolymers useful in the present invention comprise between 0.9%, preferably less than 0.6%, more preferably less than 0.4%, even more preferably less than 0.2% by moles Ji Xiao of recurring units comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof. All percentages are based on the total amount of repeating units in the polymer. Homopolymers of VDF naturally do not contain repeating units comprising such polar groups, except for their chain ends, which may be affected by the initiator and chain transfer agent used during polymerization, as known to the skilled person. The VDF-based copolymer may also comprise repeat units derived from monomers bearing such polar groups. For the purpose of calculating the total molar amount of polar groups, the chain end comprising one of the listed functional groups is counted as one repeating unit. Most preferably, the VDF-based polymer used in the present invention is free of repeating units derived from monomers comprising such functional groups.
In addition to this requirement of a small amount of polar functional groups as described above, the VDF-based copolymers suitable for use in the present invention may comprise repeating units from further monomers. The choice of such additional monomers is not particularly limited (except for the monomers containing the polar groups described above).
Non-limiting examples of suitable additional monomers are notably:
(i)C 2 -C 8 perfluoroolefins such as Tetrafluoroethylene (TFE) and Hexafluoropropylene (HFP);
(ii) Hydrogen-containing C other than VDF 2 -C 8 Olefins, e.g. Vinyl Fluoride (VF), trifluoroethylene (TrFE), of formula CH 2 ＝CH-R f Wherein R is f Is C 1 -C 6 Perfluoroalkyl groups;
(iii)C 2 -C 8 chloro-and/or bromo-and/or iodo-fluoroolefins, such as Chlorotrifluoroethylene (CTFE);
(iv) Having a CF 2 ＝CFOR f (per) fluoroalkyl vinyl ethers (PAVE), wherein R f Is C 1 -C 6 (per) fluoroalkyl, e.g. -CF 3 、-C 2 F 5 、-C 3 F 7 ；
(v) Having a CF 2 (per) fluoro-oxy-alkyl vinyl ether of CFOX, wherein X is C comprising a chain oxygen atom 1 -C 12 [ (per) fluoro ]]-oxyalkyl groups such as perfluoro-2-propoxypropyl;
(vi) (per) fluorodioxoles of the formula:
wherein R is f3 、R f4 、R f5 、R f6 Are identical to or different from each other and are independently selected from fluorine atoms and C 1 -C 6 (per) fluoroalkyl optionally containing one or more oxygen atoms, e.g. notably-CF 3 、-C 2 F 5 、-C 3 F 7 、-OCF 3 、-OCF 2 CF 2 OCF 3 The method comprises the steps of carrying out a first treatment on the surface of the Preferably, the perfluoro dioxole;
(vii) (per) fluoro-methoxy-vinyl ether (MOVE, hereinafter) having the formula: CFX (computational fluid dynamics) 2 ＝CX 2 OCF 2 OR" f Wherein R' is " f Selected from linear or branched C 1 -C 6 (per) fluoroalkyl; c (C) 5 -C 6 Cyclic (per) fluoroalkyl; and C comprising from 1 to 3 chain oxygen atoms, linear or branched 2 -C 6 (per) fluoroalkoxy, and X 2 = F, H; preferably X 2 Is F and R'. f is-CF 2 CF 3 (MOVE1)；-CF 2 CF 2 OCF 3 (MOVE 2); or-CF 3 (MOVE3)。
The VDF-based polymer used in the present application must also have a melting temperature Tm comprised between 130 ℃ and 180 ℃, preferably between 150 ℃ and 170 ℃ and must have the following total number of (a) + (b) chain ends, wherein:
(a)：-CF 2 H
(b)-CF 2 CH 3 ，
less than 70, preferably less than 60, more preferably less than 50, even more preferably less than 45, most preferably less than 40 mmoles/kg as measured by NMR.
Without being bound by theory, it is believed that the small amount of polar groups prevents curing of the electrode-forming composition and improves its physical stability over time. However, as known from the mentioned technology WO 2008/129041, small amounts or lack of polar monomers tend to give the composition low adhesion to metals. In the present application, this disadvantage is compensated for by selecting VDF-based polymers having a relatively small number of certain chain ends. The inventors have surprisingly found that by selecting VDF-based polymers having a low number of certain chain ends, the resulting electrode-forming composition has a much higher adhesion on metal than the corresponding composition using standard VDF-based polymers (see experimental section).
The VDF-based polymer having the desired low concentration of chain ends can be obtained by polymerizing VDF and further optional comonomers by aqueous emulsion polymerization in the presence of a redox initiating system comprising at least one organic free radical initiator as oxidizing agent and at least one sulfur-based reducing agent.
As known to the skilled person, redox initiation systems for the free radical polymerization of monomers are initiator systems in which the free radicals are formed by introducing at least one oxidizing agent and at least one reducing agent into the reactor. Even at very low temperatures, redox reactions are typically very rapid and they cause the formation of free radicals that initiate and propagate their polymerization in the presence of polymerizable monomers. A continuous controlled feed of redox initiator (typically in the form of two separate feeds of oxidant and reductant) can maintain the polymerization reaction until it is completed.
The oxidizing agent used to make the VDF-based polymer used in the present invention preferably comprises one or more compounds selected from the group of organic radical initiators, more preferably selected from the group of organic peroxides or percarbides, most preferably selected from the group comprising: acetylcyclohexane sulfonic acid; diacetyl peroxydicarbonate; dialkyl peroxydicarbonates, such as diethyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate; tert-butyl perneodecanoate; 2,2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile); tert-butyl perpivalate; di-octanoyl peroxide; dilauroyl peroxide; 2,2' -azobis (2, 4-dimethyl-valeronitrile); tert-butyl azo-2-cyanobutane; dibenzoyl peroxide; tert-butyl-per-2-ethylhexanoate; t-butyl peroxymaleate; 2,2' -azobis (isobutyronitrile); bis (tert-butyl-peroxy) -cyclohexane; tert-butyl peroxyisopropyl carbonate; t-butyl peracetate; 2,2' -bis (t-butylperoxy) butane; dicumyl peroxide; di-t-amyl peroxide; di-t-butyl peroxide; para-methane hydroperoxide; pinane hydroperoxide; cumene hydroperoxide; disuccinyl peroxide; t-butyl hydroperoxide.
Organic radical initiators selected from peroxides are particularly preferred, and among these, t-butyl hydroperoxide is most preferred.
The organic radical initiator is typically used at a concentration ranging from 0.001 to 20wt.%, based on the total weight of the polymerization medium.
Sulfur-based reducing agents suitable for preparing the VDF-based polymer used in the present invention are preferably selected from sulfites and sulfinates in their acid or salt form. More preferably selected from compounds corresponding to the following formula (S-I):
wherein the method comprises the steps of
M is a hydrogen atom, an ammonium ion, a monovalent metal ion;
r20 is-OH or-N (R) 4 )(R 5 ) Wherein R is 4 And R is 5 Are identical to or different from each other and are hydrogen atoms or straight-chain or branched alkyl chains having from 1 to 6 carbon atoms;
r21 is a hydrogen atom, a linear or branched alkyl group having from 1 to 6 carbon atoms, a 5-or 6-membered cycloalkyl group, a 5-or 6-membered aryl group;
r22 is-COOM, -SO 3 M、-C(＝O)R 4 、-C(＝O)N(R 4 )(R 5 )、-C(＝O)OR 4 Therein M, R 4 And R is 5 Are as defined above, and salts thereof with at least one monovalent metal ion.
Preferably, M is a hydrogen atom or a monovalent metal ion.
Preferably, the monovalent metal ion is selected from sodium and potassium ions.
Preferably, R20 is selected from hydroxyl or amino.
Preferably, R21 is selected from the group consisting of a hydrogen atom, a linear or branched alkyl group having from 1 to 3 carbon atoms, and a 5-or 6-membered aryl group.
Preferably, R22 is selected from the group consisting of-COOM, -SO 3 M, and C (=O) OR 4 Therein M, R 4 And R is 5 As defined above.
Preferred compounds correspond to the formula (S-I) above, wherein M is sodium, R20 is-OH, R21 is a hydrogen atom and R22 is selected from-COOM, -SO 3 M and C (=o) OR 4 Therein M, R 4 And R is 5 As defined above.
More preferred compounds corresponding to the above formula (S-I) are 2-hydroxy-2-sulfinylacetic acid or its disodium salt.
In one embodiment, the sulfur-based reducing agent is a composition CS comprising at least 40wt.% of a compound according to formula (S-I) as defined above, relative to the total weight of the composition CS.
Preferably, the composition CS comprises at most 79wt.% of a compound according to formula (S-I) as defined above, relative to the total weight of the composition CS.
Preferably, the composition CS further comprises sulfurous acid or a salt thereof (also referred to as "sulfite"), such as notably sodium sulfite.
Preferably, the composition CS comprises at least 20wt.% of the sulfurous acid or a salt thereof, relative to the total weight of the composition CS.
Preferably, the composition CS comprises at most 40wt.% of the sulfurous acid or a salt thereof, relative to the total weight of the composition CS.
Preferably, the composition CS further comprises a compound [ compound S ] 3 ]The compound comprises at least one sulfonic acid group.
Preferably, the compound S 3 Conform to the following S 3 -I：
Wherein M, R, R21 and R22 have the same meanings as defined above for the compound of formula (S-I), and salts thereof with at least one monovalent metal ion.
Preferably, the composition CS comprises at least 1wt.%, relative to the total weight of the composition CS, of a formula (S) as defined above 3 -compounds of I).
Preferably, the composition CS comprises up to 40wt.%, relative to the total weight of the composition CS, of a formula (S 3 -compounds of I).
Suitable examples of such compositions CS and compounds are those from the Bulgerman groupUnder the trade name->Are commercially available.
In the preparation of VDF polymers suitable for use in the present invention, at least a part of the polymerization reaction, preferably at least 70%, more preferably at least 80% of the reaction, even more preferably at least 90% of the reaction (measured in view of the molar conversion% of the monomers fed) has to be carried out in the presence of an organic radical initiator and a sulfur-based reducing agent. However, other initiators may be used in combination. Good results were obtained by starting the polymerization reaction by feeding a small amount of persulfate inorganic initiator in combination with a sulfur-based reducing agent, and then continuing the polymerization reaction using an organic radical initiator in combination with a sulfur-based reducing agent until the polymerization reaction is completed.
Optionally, preparing the VDF-based polymer of the present invention by emulsion polymerization in the presence of a redox initiator system further comprises using additional ingredients known in the art, such as typically one or more surfactants, one or more chain transfer agents and one or more accelerators.
Surfactants may optionally be used to stabilize the aqueous emulsion. Fluorinated surfactants, such as those notably conforming to the formula:
R * -X B- (T + )
wherein the method comprises the steps of
R * Is C 5 -C 16 (per) fluoroalkyl chain or (per) fluoropolyoxyalkylene chain, X B- is-COO - or-SO 3 - ，T + Selected from: h + 、NH 4 + Alkali metal ions.
Among these, preferred surfactants are selected from the group consisting of fluorinated surfactants such as: ammonium perfluorooctanoate; (per) fluoropolyoxyalkylene groups terminated with one or more carboxyl groups, optionally salified with sodium, ammonium and alkali metal, more preferably with sodium; and partially fluorinated alkyl sulfonates.
Preferably, the surfactant is used in an amount of from 0.05 to 5wt.%, based on the total weight of the final polymer (P).
According to an alternative and more preferred embodiment, the emulsion polymerization is carried out in the absence of said fluorinated surfactant.
According to another alternative and more preferred embodiment, the emulsion polymerization is carried out in the presence of a non-fluorinated surfactant, such as for example an alkyl sulfate surfactant.
The emulsion polymerization can also be carried out in the presence of small amounts of fluorinated or non-fluorinated surfactants, used in amounts not exceeding 100ppm, more preferably not exceeding 50ppm, with respect to the total weight of the final polymer (P).
The optional chain transfer agent, if present, may be selected from ketones, esters, ethers or aliphatic alcohols having from 3 to 10 carbon atoms, such as acetone, ethyl acetate, diethyl ether, methyl-t-butyl ether, isopropanol, and the like; a chloro (fluoro) hydrocarbon having from 1 to 6 carbon atoms, optionally containing hydrogen, such as chloroform, trichlorofluoromethane; bis (alkyl) carbonates wherein the alkyl group has from 1 to 5 carbon atoms, such as bis (ethyl) carbonate, bis (isobutyl) carbonate. The chain transfer agent may be fed into the polymerization medium at the beginning, continuously during the polymerization or in discrete amounts (stepwise), continuous or stepwise feeding being preferred.
The promoter, if present, is selected from the group consisting of, more preferably consisting of: an organo-onium compound, an amino-phosphonium derivative, a phosphane and an imine compound.
Examples of accelerators that may be used include: quaternary ammonium or phosphonium salts, as described notably in EP 335705A (MINNESOTA MINING) and US 3876654 (DUPONT); aminophosphonium salts, as notably described in US 4259469 (MONTEDISON s.p.a.); phosphanes, as described notably in US 3752787 (dupont); imine compounds, as described in EP 0120462A (Monte Edison Co.) or as described in EP 0182299A (Xudi chemical Co., ltd. (ASAHI CHEMICAL))
Quaternary phosphonium salts and aminophosphonium salts are preferred, and tetrabutylphosphonium, tetrabutylammonium, and salts of 1, 1-biphenyl-1-benzyl-N-diethyl-phosphane having the formula:
the accelerators are preferably used in amounts of from 0.05phr and up to 10phr, based on the total weight of the polymer (P).
In addition to the above, the preparation of the VDF-based polymer of the present invention is optionally carried out using other conventional additives such as reinforcing fillers (e.g. carbon black), thickeners, pigments, antioxidants, stabilizers, etc.
The process for the preparation of the VDF-based polymer according to the present invention may preferably be carried out in a continuous, or semi-batch or batch mode at a temperature which one skilled in the art can select based on the organic peroxide chosen. Preferably, the process of the present invention is carried out at a temperature of from 40 ℃ to 120 ℃, more preferably from 50 ℃ to 100 ℃.
The process of the invention is preferably carried out at a pressure of between 10 and 60 bar, more preferably from 25 to 55 bar.
The described process provides VDF-based polymers in the form of aqueous dispersions suitable for use in the present invention. Typically, for use in the electrode-forming composition of the present invention, any suitable method or combination of methods known in the art is used, for example, recovery of the VDF-based polymer in powder form from the dispersion by filtration, coagulation, concentration, spray drying. The resulting powder may optionally be washed with demineralised water and dried.
Electroactive material
The electrode-forming composition of the present invention comprises one or more electroactive materials. For the purposes of the present invention, the term "electroactive material" is intended to mean a compound capable of binding or intercalating alkali or alkaline earth metal ions into its structure and substantially releasing alkali or alkaline earth metal ions therefrom during the charge and discharge phases of an electrochemical device. The electroactive material is preferably capable of binding or intercalating and releasing lithium ions.
The nature of the electroactive material in the electrode-forming composition of the invention depends on whether the composition is used to make a positive electrode or a negative electrode.
In the case of forming a positive electrode for a lithium ion secondary battery, the electroactive compound may comprise one or more lithium-containing compounds selected from the group consisting of:
(i) Having LiMQ 2 Wherein M is at least one metal selected from the group consisting of transition metals, preferably selected from the group consisting of Co, ni, fe, mn, cr and V, and Q is a chalcogen, preferably selected from the group consisting of O or S. Among these, preferred is the use of a LiMO of the formula 2 Wherein M is as defined above.Particularly preferred examples thereof may include: liCoO 2 、LiNiO 2 、LiNi x Co 1-x O 2 (0<x<1) Spinel structured LiMn 2 O 4 。
(ii) Having the formula M1M2 (JO) 4 ) f E 1-f Wherein M1 is lithium, which may be partially substituted with less than 20% of one or more other alkali metals of the M1 metal; m2 is a transition metal at an oxidation level of +2 selected from Fe, mn, ni, or mixtures thereof, which may be substituted with one or more additional metal moieties at an oxidation level between +1 and +5 and accounting for less than 35% of the M2 metal; JO (joint-joint) 4 Is any oxyanion, wherein J is P, S, V, si, nb, mo or a combination thereof; e is a fluoride anion, hydroxide anion or chloride anion; f is JO 4 The molar fraction of oxyanions is generally comprised between 0.75 and 1.
M as defined above 1 M 2 (JO 4 ) f E 1-f The electroactive material is preferably phosphate-based and may have an ordered or modified olivine structure.
More preferably, in the case of forming a positive electrode, the electroactive compound has the formula Li 3-x M’ y M” 2-y (JO 4 ) 3 Wherein 0.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.2, M 'and M' are the same or different metals, at least one of them being a transition metal; JO (joint-joint) 4 Preferably PO 4 It may be partially replaced by another oxyanion, where J is S, V, si, nb, mo or a combination thereof. Still more preferably, the electroactive compound is a compound having the formula Li (Fe x Mn 1-x )PO 4 Wherein 0.ltoreq.x.ltoreq.1, wherein x is preferably 1 (i.e. having the formula LiFePO) 4 Lithium iron phosphate).
(iii) A lithium-containing composite metal oxide having the following general formula (III):
LiNi x M1 y M2 z Y 2 (III)
wherein M1 and M2 are the same or different from each other and are transition metals selected from Co, fe, mn, cr and V, 0.5.ltoreq.x.ltoreq.1, wherein y+z=1-x, and Y represents a chalcogen element, preferably selected from O and S.
The electroactive material in this embodiment is preferably a compound having the formula (III), wherein Y is O. In another preferred embodiment, M1 is Mn and M2 is Co, or M1 is Co and M2 is Al.
Examples of such active materials include LiNi x Mn y Co z O 2 (hereinafter referred to as NMC) and LiNi x Co y Al z O 2 (hereinafter referred to as NCA).
In particular for LiNi x Mn y Co z O 2 Changing the content ratio of manganese, nickel and cobalt can adjust the power and energy performance of the battery.
In this embodiment of the invention, the compound AM is preferably a compound of the formula (III) as defined above, wherein 0.5.ltoreq.x.ltoreq.1, 0.1.ltoreq.y.ltoreq.0.5, and 0.ltoreq.z.ltoreq.0.5.
Non-limiting examples of suitable positive electrode electroactive materials having formula (III) notably include:
LiNi 0.5 Mn 0.3 Co 0.2 O 2 ，
LiNi 0.6 Mn 0.2 Co 0.2 O 2 ，
LiNi 0.8 Mn 0.1 Co 0.1 O 2 ，
LiNi 0.8 Co 0.15 Al 0.05 O 2 ，
LiNi 0.8 Co 0.2 O 2 ，
LiNi 0.8 Co 0.15 Al 0.05 O 2 ，
LiNi 0.6 Mn 0.2 Co 0.2 O 2
LiNi 0.8 Mn 0.1 Co 0.1 O 2 ，
LiNi 0.9 Mn 0.05 Co 0.05 O 2 。
among these, the compounds:
LiNi 0.8 Co 0.15 Al 0.05 O 2 ，
LiNi 0.6 Mn 0.2 Co 0.2 O 2 ，
LiNi 0.8 Mn 0.1 Co 0.1 O 2 ，
LiNi 0.9 Mn 0.05 Co 0.05 O 2 。
particularly preferred.
In the case of forming the negative electrode of a lithium ion secondary battery, the electroactive compound may preferably comprise one or more carbon-based materials and/or one or more silicon-based materials.
In some embodiments, the carbon-based material may be selected from graphite (e.g., natural or synthetic graphite), graphene, or carbon black.
These materials may be used singly or as a mixture of two or more thereof.
The carbon-based material is preferably graphite.
The silicon-based compound may be one or more selected from the group consisting of: chlorosilanes, alkoxysilanes, aminosilanes, fluoroalkylsilanes, silicon chloride, silicon carbide, and silicon oxide. More particularly, the silicon-based compound may be silicon oxide or silicon carbide.
When present in the electroactive compound, the silicon-based compound is included in an amount ranging from 1% to 60% by weight, preferably from 5% to 20% by weight, relative to the total weight of the electroactive compound.
The benefits provided by the VDF-based polymers specifically selected in the present invention are particularly evident when electroactive materials having the general formula:
Li(Fe x Mn (1-x) )PO 4 wherein x is more than or equal to 0 and less than or equal to 1,
and in particular LiFePO4. Thus, for the purposes of the present invention, are used to form positive electrodes and comprise these Li (Fe/MN) PO-based materials 4 The electrode-forming composition of the electroactive material of (2) is particularly preferred.
The electrode-forming composition of the present invention optionally comprises one or more solvents.
The solvent used to form the composition for the negative electrode may contain water and may preferably be water. This allows for reduced overall use of organic solvents, thereby reducing costs, reducing flammable materials, and reducing environmental impact.
The solvent in the composition for forming a positive electrode contains one or more organic solvents, preferably polar solvents, examples of which may include: n-methyl-2-pyrrolidone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, dioxane, tetrahydrofuran, tetramethylurea, triethyl phosphate, and trimethyl phosphate. These organic solvents may be used alone or as a mixture of two or more substances.
The electrode forming composition of the present invention typically comprises from 0.5% by weight to 10% by weight, preferably from 0.7% by weight to 5% by weight of the polymer. These compositions also comprise from 80% by weight to 99% by weight of one or more electroactive materials, all percentages being by weight relative to the total solids content of the composition.
The term "total solids content" means "all ingredients of the electrode-forming composition of the present invention except the solvent".
In general, in the electrode-forming composition of the present invention, the solvent is present in an amount of from 10% by weight to 90% by weight of the total amount of the composition (C). In particular, for the composition for forming a negative electrode, the solvent is preferably present in an amount of from 25% by weight to 75% by weight, more preferably from 30% by weight to 60% by weight of the total composition.
For the composition for forming a positive electrode, the solvent is preferably present in an amount of from 5% by weight to 60% by weight, more preferably from 15% by weight to 40% by weight of the total amount of the composition.
The electrode-forming composition of the present invention may further comprise one or more optional conductive agents in order to improve the conductivity of the resulting electrode made from the composition of the present invention. Conductive agents for batteries are known in the art.
Examples thereof may include: carbonaceous materials such as carbon black, graphite fines, carbon nanotubes, graphene or fibers, or fines or fibers of metals such as nickel or aluminum.
When present, the conductive agent is different from the carbon-based materials described above.
The amount of the optional conductive agent is preferably from 0% to 30% by weight relative to the total solids in the electrode-forming composition. In particular, for positive electrode-forming compositions, the optional conductive agent is typically from 0% by weight to 10% by weight, more preferably from 0% by weight to 5% by weight of the total amount of solids in the composition.
For compositions for forming negative electrodes that do not contain silicon-based electroactive compounds, the optional conductive agent is typically from 0% by weight to 5% by weight, more preferably from 0% by weight to 2% by weight of the total amount of solids in the composition, while for compositions for forming negative electrodes that contain silicon-based electroactive compounds, it has been found to be beneficial to introduce a greater amount of the optional conductive agent, typically from 5% by weight to 20% by weight of the total amount of solids in the composition.
Electrode-forming compositions are typically prepared by dissolving or dispersing one or more binder polymers (i.e., one or more VDF-based polymers in the context of the present invention) in a suitable solvent, such as NMP, for example, and adding the electroactive material and other optional ingredients to form a slurry under suitable mixing. As described above, the electrode-forming composition is typically applied to the current collector using procedures such as casting, printing, and roll coating. Thus, the viscosity of the composition must preferably be controlled so that the viscosity is within the acceptable range for the device in question. As known to the skilled artisan, the amount of solvent is typically a factor that can be used to control the viscosity of the electrode-forming composition.
The electrode-forming composition of the present invention can be used in a method for manufacturing an electrode, the method comprising:
(i) Providing a metal substrate having at least one surface;
(ii) There is provided an electrode-forming composition according to the present invention,
(iii) Applying the electrode-forming composition provided in step (ii) to at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate coated on at least one surface with the composition;
(iv) Drying the assembly provided in step (iii).
The metal substrate is typically a foil, mesh or net made of a metal such as copper, aluminum, iron, stainless steel, nickel, titanium or silver.
In step (iii) of the process of the present invention, the electrode-forming composition is typically applied to at least one surface of the metal substrate by any suitable procedure, such as casting, printing and roll coating.
Optionally, step (iii) may typically be repeated one or more times by applying the electrode-forming composition provided in step (ii) to the component provided in step (iv).
Step (iv) is suitably carried out at a temperature comprised between 50 ℃ and 200 ℃, preferably between 80 ℃ and 180 ℃ for a time comprised between 5 minutes and 48 hours, preferably between 30 minutes and 24 hours.
The assembly obtained in step (iv) may be further subjected to a compression step (such as a calendaring process) to achieve the target porosity and density of the electrode.
Preferably, the assembly obtained in step (iv) is hot pressed, the temperature during the compression step comprising from 25 ℃ to 130 ℃, preferably about 90 ℃.
Preferred target porosities of the obtained electrode are comprised between 15% and 40%, preferably from 25% and 30%. The porosity of the electrode is calculated as an integral complement to the ratio between the measured density and the theoretical density of the electrode, wherein:
the measured density is given by the mass divided by the volume of the circular portion of the electrode having a diameter equal to 24mm and the measured thickness; and is also provided with
The theoretical density of the electrodes is calculated as the sum of the product of the densities of the electrode components multiplied by their volume ratios in the electrode formulation.
In another example, the invention relates to an electrode obtainable by the method of the invention.
Accordingly, the present invention relates to an electrode comprising:
-a metal substrate, and
-at least one layer directly adhered to at least one surface of the metal substrate, the at least one layer consisting of a composition comprising:
(a) One or more vinylidene fluoride (VDF) based polymers wherein:
(i) The VDF-based polymer comprises at least 70% by mole of repeating units derived from vinylidene fluoride (VDF) based on the total amount of repeating units of the polymer;
(ii) The VDF-based polymer comprises between 0.9% by moles Ji Xiao of recurring units based on the total amount of recurring units of the polymer, these recurring units comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof;
(iii) The VDF-based polymer has a melting temperature Tm comprised between 130 ℃ and 180 DEG C
(iv) The VDF-based polymer has a chain end-CF of less than 70 mmoles/kg as measured by NMR 2 H and-CF 2 CH 3 Total number of (2)
(b) One or more electroactive materials.
The layer of the electrode of the invention typically has a thickness comprised between 10 μm and 500 μm, preferably between 50 μm and 250 μm, more preferably between 70 μm and 150 μm.
The electrode-forming composition of the present invention is particularly suitable for manufacturing a positive electrode for an electrochemical device.
The electrode of the present invention is particularly suitable for use in an electrochemical device, particularly a secondary battery, including the electrode.
For the purposes of the present invention, the term "secondary battery" is intended to mean a rechargeable battery. The secondary battery of the present invention is preferably an alkali metal or alkaline earth metal secondary battery. The secondary battery of the present invention is more preferably a lithium ion secondary battery. The electrochemical device according to the present invention may be manufactured by standard methods known to those skilled in the art.
The disclosure of any patent, patent application, or publication that incorporates the application by reference should be given priority if it conflicts with the description of the present application to the extent that the term "does not become clear".
The application will now be described with reference to the following examples, which are intended to be illustrative only and are not intended to limit the scope of the application.
Experimental part
Raw materials
Polymer 1PVDF homopolymer in powder form, having tm=163 ℃, a number average molecular weight of about 867kDa, and a chain end-CF of 38mmol/Kg 2 H and-CF 2 CH 3 Is a number of (3).
Polymer 2PVDF homopolymer in powder form, having tm=163 ℃, a number average molecular weight of about 783kDa, and a chain end-CF of 41mmol/Kg 2 H and-CF 2 CH 3 Is a number of (3).
Polymer 3PVDF homopolymer in powder form, having tm=161 ℃, having a number average molecular weight of approximately 842kDa, and a chain end-CF of 89mmol/Kg 2 H and-CF 2 CH 3 Is a number of (3).
Polymer 4PVDF copolymer in powder form, having a content of 1% of recurring units derived from acrylic acid, tm=162 ℃, having a number average molecular weight of about 900 kDa.
Polymers 1 and 2 were prepared according to the method described in WO 2019002180A1 by emulsion polymerization using a redox initiator system (t-butyl hydroperoxide and disodium 2-hydroxy-2-sulfinylacetate) at 80 ℃ followed by coagulation, washing and drying. Polymer 3 was prepared by the same method using a standard free radical initiator (ammonium persulfate) at a temperature of 105℃which is necessary for the non-redox initiator to function. Polymer 4 is available from Sorve specialty Polymer company (Solvay Specialty Polymers).
Conductivity-imparting additive: carbon nanotubes NC7000 from Nanocyl corporation TM 。
Electroactive material: from Zhuang Xinmo Feng Co (Johnson Matthey) as LifeP2 C-LiFePO 4 LiFePO4 having a particle size D50.5 μm was obtained.
NMP is 99% N-methyl-2-pyrrolidone from Sigma Aldrich
Determination of melting Point
Melting point Tm is measured by DSC according to ASTM D3418 standard as the second melting temperature. The procedure was as follows: the polymer sample was heated from 10 ℃ to 230 ℃ to melt with a temperature ramp of 10 ℃/min. The sample was then held at 230 ℃ for 5 minutes and then recrystallized with a ramp down of 10 ℃/min to reduce the temperature from 230 ℃ to 10 ℃. The polymer was then held at 10℃for 10min and heated again to 230℃with a temperature ramp of 10℃per min. The melting point is determined as the melting temperature during this second ramp.
Determination of chain ends
The end groups of the polymer were measured by NMR analysis by: using HFCP-PFG Triple HFCP-PFG probe with 5mm 502-8 (Norell, inc.) NMR sample tube in a Varian VNMS 500 NMR spectrometer (for 1 H operates at 499.86MHz and is for 19 F was run at 470.28 MHz) was recorded at 60 ℃. NMR experiments were performed using 40mg polymer samples dissolved in 0.75ml deuterated acetone (99.9% d, obtained from sigma aldrich) at 60 ℃ with Tetramethylsilane (TMS) as internal standard. Using a 5.05us 45 degree pulse length, 5s relaxation delay, 2.3s acquisition time, 16K complex point, 7kHz spectral width, and 1500 repetitions 1 H。
Using 4.44us 45 degree pulse length, 5s relaxation delay, 0.695s acquisition time, 16K complex point, 23.5kHz spectral width, and 2000 repetitions 19 F。
The total number of chain ends (a) + (b) of the following types for the polymers tested:
(a)-CF 2 h and
(b)-CF 2 CH 3 measured in millimoles per kilogram of chain end of polymer.
The measurement and the related calculation of the chain ends were performed according to the procedure described in "Comprehensive Characterization of Chain End Groups of Vinylidene Fluoride Based Polymers [ comprehensive characterization of chain end groups of vinylidene fluoride-based polymers ]" (macromol. Symp. [ university conference: 2013, 324, 41-48).
General preparation of electrode-forming compositions
The composition was prepared as follows. First 8g of polymer was added to 92g of NMP with stirring. 24.5g of this mixture was stirred with 53.62g of electroactive material, 10.5g of a 4% by weight carbon nanotube dispersion in NMP and 11.38g of additional NMP in a centrifugal mixer for 10 minutes. The resulting slurry had a Total Solids Content (TSC) of 56% and its composition was as follows:
TABLE 1
| Material | Net mass/g | % w/w of solid composition |
| Polymer | 1.96 | 3.5 |
| Carbon nanotubes | 0.42 | 0.75 |
| Electroactive material | 53.62 | 95.75 |
| Total solids content | 56 | |
| NMP | 44 | |
| Total mass of | 100 |
The premix was then mixed using a high speed butterfly impeller at 2000rpm for 1 hour.
The following example compositions were prepared:
example 1Polymer 1 was used as polymer component according to the general preparation procedure.
Example 2Polymer 2 was used as polymer component according to the general preparation procedure.
Example 3c(comparative) -Polymer 3 was used as polymer component according to the general preparation procedure.
Example 4c(comparative) -Polymer 4 was used as polymer component according to the general preparation procedure.
Physical stability test
As described above, the electrode-forming composition needs to remain spreadable over time in order to be properly stored and used in a manufacturing facility at an appropriate time.
The compositions of examples 1-4 were left in a closed container at 25 ℃ for 7 days and then visually inspected with the following results:
TABLE 2
| Curing | |
| Example 1 | Whether or not |
| Example 2 | Whether or not |
| Example 3c | Whether or not |
| Example 4c | Is that |
The results of the physical stability test show that the slurry of example 4c did not cure and was not spreadable after storage. The slurry forms a solid gel-like mass that cannot be used to prepare an electrode.
Adhesion peel force method
The adhesion to Al of all the spreadable slurries obtained in examples, i.e. examples 1, 2 and 3c, was measured. The peel force of example 4c could not be measured because the slurry was not spreadable and no electrode could be prepared.
For the adhesion behavior of the compositions of comparative examples 1, 2 and 3c, electrodes were obtained by casting the compositions on 15 μm thick Al foil with a doctor blade and drying the coating thus obtained in a vacuum oven at a temperature of 90 ℃ for about 50 minutes. The thickness of the dried coating was about 110 μm.
The electrodes prepared as described above were subjected to a peel test at 20 ℃ with the setup described in standard ASTM D903 at a speed of 300mm/min in order to evaluate the adhesion of the dried coating to Al foil. The measured values in N/m were normalized with respect to example 3c, the adhesion value of which was designated 1. The results obtained are reported in the following table:
TABLE 3 Table 3
| Adhesion [ N/m ]] | Normalized adhesion [%] | |
| Example 1 | 4.49 | 197 |
| Example 2 | 3.04 | 134 |
| Example 3c | 2.28 | 100 |
The results surprisingly show that the electrodes of examples 1 and 2, prepared by using the combination of VDF-based polymers selected according to the teachings of the present invention (having a small amount of chain ends after redox polymerization), have a much better adhesion than the electrode of comparative example 3c, prepared using standard VDF-based polymers having essentially the same monomer composition, melting temperature and molecular weight (having a larger amount of chain ends after standard radical thermal initiator).
Furthermore, the results of the physical stability test show that the composition according to the invention is stable, whereas the composition using a VDF copolymer comprising polar monomers (typically used in electrode-forming compositions in order to increase the adhesion of the composition to metal foil) is not physically stable, a solid gel-like mass is formed under the particularly stressed conditions of the test (LiFePO when combined with a VDF copolymer having a large number of polar groups 4 Active materials are particularly prone to forming solid gel-like materials).
Claims (15)
1. An electrode-forming composition comprising:
(a) One or more vinylidene fluoride (VDF) based polymers wherein:
(i) The VDF-based polymer comprises at least 70% by mole of repeating units derived from vinylidene fluoride (VDF) based on the total amount of repeating units of the polymer;
(ii) The VDF-based polymer comprises between 0.9% by moles Ji Xiao of recurring units based on the total amount of recurring units of the polymer, these recurring units comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof;
(iii) The VDF-based polymer has a melting temperature Tm comprised between 130 ℃ and 180 DEG C
(iv) The VDF-based polymer has a chain end-CF of less than 70 mmoles/kg as measured by NMR 2 H and-CF 2 CH 3 Total number of (2)
(b) One or more electroactive materials.
2. The electrode-forming composition according to claim 1, further comprising:
(c) One or more organic solvents.
3. The electrode-forming composition of any preceding claim, wherein the one or more VDF polymers have a chain end-CF of less than 60, preferably less than 50, more preferably less than 45, even more preferably less than 40 millimoles per kilogram as measured by NMR 2 H and-CF 2 CH 3 Is a number of (3).
4. The electrode forming composition of any of the preceding claims, wherein the one or more VDF-based polymers comprise at least 80%, preferably at least 90%, more preferably at least 94% by mole of repeat units derived from VDF based on the total amount of repeat units of the polymer and comprise at least 0.9%, preferably at least Ji Xiao at 0.6%, more preferably at least Ji Xiao at 0.4%, even more preferably at least Ji Xiao at 0.2%, and most preferably are free of repeat units derived from monomers comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof.
5. The electrode forming composition according to any one of the preceding claims, comprising:
-from 0.5% by weight to 10% by weight, preferably from 0.7% by weight to 5% by weight of said one or more VDF based polymers;
from 80% by weight to 99% by weight of the at least one electroactive material,
all percentages are by weight relative to the total solids content of the electrode-forming composition.
6. The electrode-forming composition of any preceding claim, wherein the one or more electroactive materials comprise one or more compounds selected from the group consisting of:
- - (i) having LiMQ 2 Wherein M is selected from transition metals, preferably from metal chalcogenides of formula (I)Co, ni, fe, mn, cr and V or mixtures thereof, and Q is a chalcogen, preferably selected from O or S or mixtures thereof;
- - (ii) a lithiated or partially lithiated transition metal oxyanion-based electroactive material having the formula:
M1M2(JO 4 ) f E (1-f)
wherein the method comprises the steps of
M1 is lithium, optionally substituted with one or more other alkali metal moieties, said one or more other alkali metals comprising less than 20% of the total M1 metal,
m2 is a transition metal at an oxidation number of +2 selected from Fe, mn, ni or mixtures thereof, optionally substituted with one or more further metal moieties at an oxidation number between +1 and +5, the one or more further metals accounting for less than 35% of the total M2 metal,
-JO 4 Is any oxyanion wherein J is selected from P, S, V, si, nb, mo or a combination thereof,
e is a fluoride, hydroxide or chloride anion or a mixture thereof
- "f" is the mole fraction of JO4 oxyanions, and is comprised between 0.75 and 1;
- - (iii) a lithium-containing composite metal oxide having the general formula:
LiNi x M1 y M2 z Y 2
wherein:
m1 and M2 are identical or different from each other and are transition metals selected from Co, fe, mn, cr and V or mixtures thereof,
0.5.ltoreq.x.ltoreq.1, and y+z=1-x,
y is a chalcogen element, preferably selected from O and S or mixtures thereof.
7. The electrode-forming composition of any preceding claim, wherein the one or more electroactive materials comprise a phosphate-based electroactive material having the formula:
Li(Fe x Mn (1-x) )PO 4 wherein 0.ltoreq.2x≤1。
8. The electrode-forming composition of any of the preceding claims, wherein the one or more electroactive materials comprise a material having the formula LiFePO 4 Lithium iron phosphate of (a).
9. The electrode-forming composition according to any of the preceding claims, wherein the VDF polymer is obtained by polymerization in an aqueous emulsion comprising vinylidene fluoride and optionally other monomers in the presence of a redox initiating system comprising at least one organic radical initiator as oxidant and at least one sulfur-based reducing agent.
10. The electrode-forming composition according to claim 8, wherein the sulfur-based reducing agent comprises at least a compound having a sulfinic acid group in its acid or salt form.
11. The electrode-forming composition according to claim 10, wherein the compound having a sulfinic acid group in its acid or salt form corresponds to the following general formula (S-I):
wherein the method comprises the steps of
R20 is selected from-OH or-N (R4) (R5),
r21 is selected from-H, a linear or branched alkyl group having from 1 to 6 carbon atoms, a 5-or 6-membered cycloalkyl group, a 5-or 6-membered aryl group;
r22 is selected from-COOM, -SO3M, -C (=o) R4, -C (=o) N (R4) (R5), -C (=o) OR4, and wherein:
m is selected from hydrogen atoms, ammonium ions and monovalent metal ions;
r4 and R5 are independently selected from-H and straight or branched alkyl groups having from 1 to 6 carbon atoms.
12. The electrode-forming composition according to claim 10, wherein the sulfinic acid group-carrying compound is 2-hydroxy-2-sulfinylacetic acid or disodium salt thereof.
13. A method for manufacturing an electrode, the method comprising:
(i) Providing a metal substrate having at least one surface;
(ii) Providing the electrode-forming composition according to any one of claims 1 to 12;
(iii) Applying the composition provided in step (ii) to the at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate coated with said composition on the at least one surface;
(iv) Drying the assembly provided in step (iii).
14. An electrode obtainable by the method according to claim 13, preferably being a cathode and comprising:
-a metal substrate, and
-at least one layer directly adhered to at least one surface of the metal substrate, the at least one layer consisting of a composition comprising:
(a) One or more vinylidene fluoride (VDF) based polymers wherein:
(i) The VDF-based polymer comprises at least 70% by mole of repeating units derived from vinylidene fluoride (VDF) based on the total amount of repeating units of the polymer;
(ii) The VDF-based polymer comprises between 0.9% by moles Ji Xiao of recurring units based on the total amount of recurring units of the polymer, these recurring units comprising a functional group selected from the group consisting of: carbonyl, carboxyl, sulfonic, sulfinic, phosphonic, hydroxyl, -SH, ester, or mixtures thereof;
(iii) The VDF-based polymer has a melting temperature Tm comprised between 130 ℃ and 180 DEG C
(iv) The VDF-based polymer has a molecular weight as measured by NMR of less than70 mmol/kg of chain end-CF 2 H and-CF 2 CH 3 Total number of (2)
(b) One or more electroactive materials.
15. An electrochemical device comprising at least one electrode according to claim 14, preferably a secondary battery.
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| PCT/EP2022/057481 WO2022200345A1 (en) | 2021-03-22 | 2022-03-22 | Composition for electrodes |
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