KR102672777B1 - Positive electrode and secondary battery comprsing the same - Google Patents
Positive electrode and secondary battery comprsing the same Download PDFInfo
- Publication number
- KR102672777B1 KR102672777B1 KR1020230090283A KR20230090283A KR102672777B1 KR 102672777 B1 KR102672777 B1 KR 102672777B1 KR 1020230090283 A KR1020230090283 A KR 1020230090283A KR 20230090283 A KR20230090283 A KR 20230090283A KR 102672777 B1 KR102672777 B1 KR 102672777B1
- Authority
- KR
- South Korea
- Prior art keywords
- active material
- positive electrode
- electrode active
- coating layer
- ppm
- Prior art date
Links
- 239000007774 positive electrode material Substances 0.000 claims abstract description 66
- 239000011734 sodium Substances 0.000 claims abstract description 55
- 239000011247 coating layer Substances 0.000 claims abstract description 43
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 38
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 38
- 239000011149 active material Substances 0.000 claims abstract description 30
- 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 claims abstract description 29
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims abstract description 29
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims abstract description 29
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 22
- 239000007773 negative electrode material Substances 0.000 claims description 19
- 229910052799 carbon Inorganic materials 0.000 claims description 15
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 10
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- 239000003575 carbonaceous material Substances 0.000 claims description 7
- 239000010410 layer Substances 0.000 claims description 7
- 239000011267 electrode slurry Substances 0.000 claims description 4
- 230000000052 comparative effect Effects 0.000 description 28
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 16
- 239000002245 particle Substances 0.000 description 15
- -1 Lithium transition metal Chemical class 0.000 description 13
- 229910052744 lithium Inorganic materials 0.000 description 12
- 239000011230 binding agent Substances 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 9
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000004020 conductor Substances 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 239000008151 electrolyte solution Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- 239000010936 titanium Substances 0.000 description 4
- 229960005196 titanium dioxide Drugs 0.000 description 4
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 4
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 3
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- 239000006245 Carbon black Super-P Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 3
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000006230 acetylene black Substances 0.000 description 3
- 239000000701 coagulant Substances 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 229910021382 natural graphite Inorganic materials 0.000 description 3
- 229910052758 niobium Inorganic materials 0.000 description 3
- 239000010955 niobium Substances 0.000 description 3
- 239000004745 nonwoven fabric Substances 0.000 description 3
- 239000002243 precursor Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052726 zirconium Inorganic materials 0.000 description 3
- DHKHKXVYLBGOIT-UHFFFAOYSA-N 1,1-Diethoxyethane Chemical compound CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 description 2
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- VUPKGFBOKBGHFZ-UHFFFAOYSA-N dipropyl carbonate Chemical compound CCCOC(=O)OCCC VUPKGFBOKBGHFZ-UHFFFAOYSA-N 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 229910000358 iron sulfate Inorganic materials 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- KKQAVHGECIBFRQ-UHFFFAOYSA-N methyl propyl carbonate Chemical compound CCCOC(=O)OC KKQAVHGECIBFRQ-UHFFFAOYSA-N 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- YULBFWISFJEMQB-UHFFFAOYSA-N oxotin titanium Chemical compound [Sn]=O.[Ti] YULBFWISFJEMQB-UHFFFAOYSA-N 0.000 description 2
- 229920002401 polyacrylamide Polymers 0.000 description 2
- 229920002239 polyacrylonitrile Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920006254 polymer film Polymers 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- MBNVSWHUJDDZRH-UHFFFAOYSA-N 2-methylthiirane Chemical compound CC1CS1 MBNVSWHUJDDZRH-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910018626 Al(OH) Inorganic materials 0.000 description 1
- 229910016569 AlF 3 Inorganic materials 0.000 description 1
- 229910017119 AlPO Inorganic materials 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229910000925 Cd alloy Inorganic materials 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M Methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- QXZUUHYBWMWJHK-UHFFFAOYSA-N [Co].[Ni] Chemical compound [Co].[Ni] QXZUUHYBWMWJHK-UHFFFAOYSA-N 0.000 description 1
- KLARSDUHONHPRF-UHFFFAOYSA-N [Li].[Mn] Chemical compound [Li].[Mn] KLARSDUHONHPRF-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000012461 cellulose resin Substances 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- CKFRRHLHAJZIIN-UHFFFAOYSA-N cobalt lithium Chemical compound [Li].[Co] CKFRRHLHAJZIIN-UHFFFAOYSA-N 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000011357 graphitized carbon fiber Substances 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- RSNHXDVSISOZOB-UHFFFAOYSA-N lithium nickel Chemical compound [Li].[Ni] RSNHXDVSISOZOB-UHFFFAOYSA-N 0.000 description 1
- 229910001386 lithium phosphate Inorganic materials 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002931 mesocarbon microbead Substances 0.000 description 1
- 239000011302 mesophase pitch Substances 0.000 description 1
- 239000002905 metal composite material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011255 nonaqueous electrolyte Substances 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002296 pyrolytic carbon Substances 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011787 zinc oxide Substances 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
- 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
- H01M4/366—Composites as layered products
-
- 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
- H01M4/52—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
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Composite Materials (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
본 발명은 리튬철 인산화물계 활물질, 및 상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하는 양극 활물질을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함하고, 상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며, 상기 코팅층에 포함된 상기 나트륨 원소: 상기 탄탈륨 원소의 중량비는 1:0.1 내지 1:0.5인 양극 및 이를 포함하는 이차 전지를 제공한다.The present invention includes a positive electrode active material including a lithium iron phosphate-based active material and a coating layer formed on the lithium iron phosphate-based active material, wherein the coating layer includes sodium (Na) elements and tantalum (Ta) elements, and the positive electrode active material Based on the total weight, the total content of the sodium element and the tantalum element is included in the range of 500 ppm to 2,000 ppm, and the weight ratio of the sodium element to the tantalum element included in the coating layer is 1:0.1 to 1:0.5, and the anode and the same. Provides a secondary battery that
Description
본 발명은 양극 및 이를 포함하는 이차 전지에 관한 것이다.The present invention relates to a positive electrode and a secondary battery including the same.
전자, 통신 및 우주 산업이 발전됨에 따라, 에너지 동력원으로서 이차전지(secondary battery)의 수요가 급격히 증대되고 있다. 특히, 글로벌 친환경 정책의 중요성이 강조됨에 따라 전기 자동차 시장이 비약적으로 성장 중이며, 국내외에서 이차전지에 관한 연구 개발이 활발히 이루어지고 있다.As the electronics, communications, and space industries develop, the demand for secondary batteries as an energy power source is rapidly increasing. In particular, as the importance of global eco-friendly policies is emphasized, the electric vehicle market is growing rapidly, and research and development on secondary batteries is being actively conducted at home and abroad.
다양한 이차전지 중에서도 높은 방전 전압 및 에너지 밀도를 가진 리튬 이차전지는 각종 모바일 기기 및 다양한 전자제품의 에너지원으로 널리 사용되고 있다. Among various secondary batteries, lithium secondary batteries with high discharge voltage and energy density are widely used as an energy source for various mobile devices and various electronic products.
리튬 이차전지의 양극 활물질로는 리튬 전이금속 복합 산화물이 이용되고 있으며, 이중에서도 작용전압이 높고 용량 특성이 우수한 LiCoO2의 리튬코발트 복합금속 산화물이 주로 사용되고 있다. 그러나, LiCoO2는 안정성이 낮고 고가이기 때문에, 리튬 이차전지를 대량 생산하기 어려운 문제점이 있다.Lithium transition metal composite oxide is used as a positive electrode active material for lithium secondary batteries, and among these, lithium cobalt composite metal oxide of LiCoO 2 is mainly used, which has a high operating voltage and excellent capacity characteristics. However, because LiCoO 2 has low stability and is expensive, it is difficult to mass-produce lithium secondary batteries.
이에 LiCoO2를 대체하기 위한 재료로서, 리튬망간 복합금속 산화물, 리튬철 인산화물, 리튬니켈 복합금속 산화물 등이 개발되었다. 이중에서 올리빈 구조를 갖는 리튬철 인산화물(LiFePO4)은 3.6g/cm3의 높은 체적 밀도를 가지며 이론 용량은 약 170mAh/g을 나타낸다. Accordingly, as materials to replace LiCoO 2 , lithium manganese composite metal oxide, lithium iron phosphate, and lithium nickel composite metal oxide were developed. Among these, lithium iron phosphate (LiFePO 4 ) with an olivine structure has a high volume density of 3.6 g/cm 3 and a theoretical capacity of about 170 mAh/g.
다만, 리튬철 인산화물(LiFePO4)은 낮은 전기 전도성으로 인해, LiFePO4를 양극 활물질로서 사용하는 경우 전지의 내부 저항이 증가되며, 이로 인해 방전 용량 및 수명 특성이 저하되는 문제가 발생하였다. However, due to the low electrical conductivity of lithium iron phosphate (LiFePO 4 ), when LiFePO 4 is used as a positive electrode active material, the internal resistance of the battery increases, which causes the problem of deterioration of discharge capacity and lifespan characteristics.
특히, 최근에는 하이브리드 자동차나 전기 자동차의 구동용 전원으로서, 리튬 이차전지를 적용하고 있는 바, 리튬 이차전지의 향상된 방전 용량 및 우수한 수명 특성을 가지는 것이 요구되고 있다.In particular, in recent years, lithium secondary batteries have been used as a power source for driving hybrid vehicles and electric vehicles, and there is a demand for lithium secondary batteries to have improved discharge capacity and excellent lifespan characteristics.
본 발명은 방전 용량 및 수명 특성이 향상된 양극 및 이를 포함하는 이차 전지를 제공한다.The present invention provides a positive electrode with improved discharge capacity and lifespan characteristics and a secondary battery including the same.
본 발명에 따른 양극은 리튬철 인산화물계 활물질, 및 상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하는 양극 활물질을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함하고, 상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며, 상기 코팅층에 포함된 상기 나트륨 원소: 상기 탄탈륨 원소의 중량비는 1:0.1 내지 1:0.5이다.The positive electrode according to the present invention includes a positive electrode active material including a lithium iron phosphate-based active material and a coating layer formed on the lithium iron phosphate-based active material, wherein the coating layer includes sodium (Na) elements and tantalum (Ta) elements, Compared to the total weight of the positive electrode active material, the total content of the sodium element and the tantalum element is included in the range of 500 ppm to 2,000 ppm, and the weight ratio of the sodium element to the tantalum element contained in the coating layer is 1:0.1 to 1:0.5.
본 발명의 일 실시예에 있어서, 상기 양극은 폴리아크릴아마이드(Polyacrylamide), 폴리우레탄(polyurethane), 및 폴리아크릴로나이트릴(polyacrylonitrile)로 이루어진 군에서 선택되는 1종 이상의 수평균 분자량 30,000 g/mol 내지 80,000 g/mol를 가지는 바인더 응집제를 포함할 수 있다.In one embodiment of the present invention, the positive electrode is one or more types selected from the group consisting of polyacrylamide, polyurethane, and polyacrylonitrile, and has a number average molecular weight of 30,000 g/mol. It may include a binder coagulant having from 80,000 g/mol.
본 발명의 일 실시예에 있어서, 상기 코팅층은 알루미늄(Al) 원소를 포함할 수 있다.In one embodiment of the present invention, the coating layer may include aluminum (Al) element.
본 발명에 따른 이차 전지는 양극, 음극, 상기 양극 및 음극 사이에 개재된 분리막을 포함하며, 상기 양극은 양극 활물질을 포함하며, 상기 양극 활물질은, 리튬철 인산화물계 활물질, 및 상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함하고, 상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며, 상기 코팅층에 포함된 상기 나트륨 원소:상기 탄탈륨 원소의 중량비는 1:0.1 내지 1:0.5이다.A secondary battery according to the present invention includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium iron phosphate-based active material and the lithium iron phosphate-based active material. It includes a coating layer formed on an active material, wherein the coating layer includes a sodium (Na) element and a tantalum (Ta) element, and relative to the total weight of the positive electrode active material, the total content of the sodium element and tantalum element is 500 ppm to 2,000 ppm. and the weight ratio of the sodium element and the tantalum element included in the coating layer is 1:0.1 to 1:0.5.
본 발명의 일 실시예에 있어서, 상기 음극은 음극 활물질을 포함하는 음극 활물질층을 포함하며, 상기 음극 활물질은 니오비움(niobium)이 도핑된 티타늄-틴-옥사이드(titanium-tin-oxide) 및 상기 니오비움이 도핑된 티타늄-옥사이드(titanium-oxide)중 적어도 하나를 포함할 수 있다. In one embodiment of the present invention, the negative electrode includes a negative electrode active material layer containing a negative electrode active material, and the negative electrode active material is titanium-tin-oxide doped with niobium and the negative electrode active material. It may include at least one of niobium-doped titanium-oxide.
본 발명은 리튬철 인산화물계 활물질 상에 나트륨 원소 및 탄탈륨 원소를 특정 함량 범위로 포함하며, 상기 나트륨 원소 및 상기 탄탈륨 원소 간의 중량비를 특정 범위로 조절함으로써, 이차전지의 방전 용량 및 수명 특성이 향상될 수 있다. The present invention includes sodium and tantalum elements in a specific content range on a lithium iron phosphate-based active material, and adjusts the weight ratio between the sodium element and the tantalum element to a specific range, thereby improving the discharge capacity and lifespan characteristics of the secondary battery. You can.
본 명세서 또는 출원에 개시되어 있는 실시예들에 대한 구조적 또는 기능적 설명들은 단지 본 발명의 기술적 사상에 따른 실시예들을 설명하기 위한 목적으로 예시된 것으로, 본 발명의 기술적 사상에 따른 실시예들은 본 명세서 또는 출원에 개시되어 있는 실시예들 이외에도 다양한 형태로 실시될 수 있으며, 본 발명의 기술적 사상이 본 명세서 또는 출원에 설명된 실시예들에 한정되는 것으로 해석되지 않는다.The structural or functional descriptions of the embodiments disclosed in the present specification or application are merely illustrative for the purpose of explaining embodiments according to the technical idea of the present invention, and the embodiments according to the technical idea of the present invention are described in this specification. Alternatively, it may be implemented in various forms other than the embodiments disclosed in the application, and the technical idea of the present invention is not to be construed as being limited to the embodiments described in this specification or application.
이하에서, 본 발명에 따른 양극 및 이차 전지에 대하여 설명한다.Below, the positive electrode and secondary battery according to the present invention will be described.
본 발명에 따른 양극은 리튬철 인산화물계 활물질, 및 상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하는 양극 활물질을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함하고, 상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며, 상기 코팅층에 포함된 상기 나트륨 원소: 상기 탄탈륨 원소의 중량비는 1:0.1 내지 1:0.5이다.The positive electrode according to the present invention includes a positive electrode active material including a lithium iron phosphate-based active material and a coating layer formed on the lithium iron phosphate-based active material, wherein the coating layer includes sodium (Na) elements and tantalum (Ta) elements, Compared to the total weight of the positive electrode active material, the total content of the sodium element and the tantalum element is included in the range of 500 ppm to 2,000 ppm, and the weight ratio of the sodium element to the tantalum element contained in the coating layer is 1:0.1 to 1:0.5.
상기 리튬철 인산화물계 활물질은 하기 화학식 1로 표시되는 화합물일 수 있다. The lithium iron phosphate-based active material may be a compound represented by the following formula (1).
[화학식 1][Formula 1]
Li1+aFe1-xMx(PO4-b)Yb Li 1+a Fe 1-x M x (PO 4-b )Y b
상기 화학식 1에서, M은 Ni, Co, Mn, Ti, Ga, Cu, V, Nb, Zr, Ce, In 및 Cu로 이루어진 군에서 선택되는 어느 하나 이상의 원소이며, Y는 F, S 및 N로 이루어진 군에서 선택되는 어느 하나 이상의 원소이고, a, b, x는 -0.5≤a≤0.5, 0≤b≤0.1, 0≤x≤0.5이다.In Formula 1, M is one or more elements selected from the group consisting of Ni, Co, Mn, Ti, Ga, Cu, V, Nb, Zr, Ce, In, and Cu, and Y is F, S, and N. It is one or more elements selected from the group consisting of, and a, b, and x are -0.5≤a≤0.5, 0≤b≤0.1, 0≤x≤0.5.
상기 리튬철 인산화물계 활물질은 LiFePO4일 수 있다.The lithium iron phosphate-based active material may be LiFePO 4 .
일반적으로, 리튬철 인산화물계 활물질은 니켈 코발트계 금속 산화물 활물질 대비 안정성이 우수하다. 다만, 리튬철 인산화물계 활물질은 낮은 전기 전도성으로 인해 양극 활물질로 사용하는 경우 이차 전지의 내부 저항이 증가되는 문제가 있다. 또한, 용량이 작고, 장기간 사용 시 사이클 특성이 급격히 저하되고, 열적 안정성이 저하되는 문제가 있다. In general, lithium iron phosphate-based active materials have superior stability compared to nickel cobalt-based metal oxide active materials. However, lithium iron phosphate-based active materials have a problem in that the internal resistance of the secondary battery increases when used as a positive electrode active material due to low electrical conductivity. In addition, the capacity is small, and when used for a long period of time, there is a problem of rapid deterioration in cycle characteristics and deterioration of thermal stability.
이에, 본 발명에 따른 양극 활물질은 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함한다. Accordingly, the positive electrode active material according to the present invention includes a coating layer formed on a lithium iron phosphate-based active material, and the coating layer includes sodium (Na) and tantalum (Ta) elements.
상기 나트륨 원소 및 탄탈륨 원소가 상기 리튬철 인산화물계 활물질 상에 형성됨으로써, 상기 리튬철 인산화물계 활물질 표면의 화학적 안정성이 향상되어, 상기 리튬철 인산화물계 활물질의 구조적 붕괴가 억제될 수 있다.By forming the sodium element and tantalum element on the lithium iron phosphate-based active material, the chemical stability of the surface of the lithium iron phosphate-based active material is improved, and structural collapse of the lithium iron phosphate-based active material can be suppressed.
또한, 리튬철 인산화물계 활물질에 포함된 금속 대비 상기 나트륨 원소 및 탄탈륨 원소가 먼저 산화되어, 상기 리튬철 인산화물계 활물질과 전해액과의 부반응이 억제될 수 있어, 리튬 이온의 이동에 따른 저항 상승이 방지될 수 있다.In addition, the sodium and tantalum elements are oxidized first compared to the metals contained in the lithium iron phosphate-based active material, so side reactions between the lithium iron phosphate-based active material and the electrolyte solution can be suppressed, preventing an increase in resistance due to the movement of lithium ions. It can be.
상기 코팅층에 상기 나트륨 원소가 형성되기 위한 전구체로서 NaOH, Ba(OH)2, Na2CO3, NaCl, CH3COONa, Na2SO4, 및 NaNO2으로 이루어진 군에서 선택된 1종 이상이 사용될 수 있다.As a precursor for forming the sodium element in the coating layer, one or more selected from the group consisting of NaOH, Ba(OH) 2 , Na 2 CO 3 , NaCl, CH 3 COONa, Na 2 SO 4 , and NaNO 2 may be used. there is.
상기 코팅층에 상기 탄탈륨 원소가 형성되기 위한 전구체로서 TaO2, 및 Ta2O5으로 이루어진 군에서 선택된 1종 이상이 사용될 수 있다.As a precursor for forming the tantalum element in the coating layer, one or more types selected from the group consisting of TaO 2 and Ta 2 O 5 may be used.
상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 300 ppm 내지 5,000 ppm, 300 ppm 내지 5,000 ppm, 400 ppm 내지 5,000 ppm, 400 ppm 내지 4,000 ppm, 400 ppm 내지 3,000 ppm, 400 ppm 내지 2,500 ppm, 500 ppm 내지 2,500 ppm, 또는 500 ppm 내지 2,000 ppm으로 포함될 수 있다. 상기 범위를 만족하는 경우, 과도한 코팅층 형성에 의한 이차 전지의 저항이 증가되거나 출력이 감소하는 현상이 억제될 수 있다.Compared to the total weight of the positive electrode active material, the total content of the sodium element and the tantalum element is 300 ppm to 5,000 ppm, 300 ppm to 5,000 ppm, 400 ppm to 5,000 ppm, 400 ppm to 4,000 ppm, 400 ppm to 3,000 ppm, and 400 ppm It may be included at 2,500 ppm, 500 ppm to 2,500 ppm, or 500 ppm to 2,000 ppm. When the above range is satisfied, the phenomenon of increased resistance or decreased output of the secondary battery due to excessive formation of a coating layer can be suppressed.
상기 코팅층에 포함된 상기 나트륨 원소: 상기 탄탈륨 원소의 중량비는 1:0.0.1 내지 1:0.8, 1:0.05 내지 1:0.8, 1:0.1 내지 1:0.8, 1:0.1 내지 1:0.7, 1:0.1 내지 1:0.6, 또는 1:0.1 내지 1:0.5일 수 있다. 상기 범위를 만족하는 경우, 양극 활물질 표면의 저항 증가 억제, 고온 저장 특성 감소, 및 충방전 용량 저하가 감소될 수 있다.The weight ratio of the sodium element to the tantalum element included in the coating layer is 1:0.0.1 to 1:0.8, 1:0.05 to 1:0.8, 1:0.1 to 1:0.8, 1:0.1 to 1:0.7, 1 :0.1 to 1:0.6, or 1:0.1 to 1:0.5. When the above range is satisfied, the increase in resistance of the surface of the positive electrode active material can be suppressed, the high-temperature storage characteristics can be reduced, and the decrease in charge/discharge capacity can be reduced.
상기 코팅층은 알루미늄 원소를 포함할 수 있다. 상기 코팅층에 알루미늄 원소가 형성되기 위한 전구체로서 Al2O3, Al(OH)3, AlF3, AlBr3, AlPO4, AlCl3, Al(NO)3, Al(H2PO4)3, 및 C2H5O4Al으로 이루어진 군에서 선택된 1종 이상이 사용될 수 있다. 상기 알루미늄은 양극 활물질 표면의 저항 증가를 억제시켜, 출력이 감소하는 현상이 억제될 수 있다.The coating layer may include aluminum element. As a precursor for forming aluminum elements in the coating layer, Al 2 O 3 , Al(OH) 3 , AlF 3 , AlBr 3 , AlPO 4 , AlCl 3 , Al(NO) 3 , Al(H 2 PO 4 ) 3 , and One or more species selected from the group consisting of C 2 H 5 O 4 Al may be used. The aluminum suppresses an increase in resistance on the surface of the positive electrode active material, thereby suppressing a decrease in output.
상기 리튬철 인산화물계 활물질 내에 지르코늄(Zr) 원소가 도핑된 구조를 포함할 수 있다. 상기 지르코늄 원소는 양극 활물질의 기계적 특성을 향상시켜, 이차 전지의 제조 공정 또는 외부 충격에 의해 양극 활물질이 깨지는 현상이 최소화될 수 있다.The lithium iron phosphate-based active material may include a structure doped with a zirconium (Zr) element. The zirconium element improves the mechanical properties of the positive electrode active material, thereby minimizing the phenomenon of the positive active material being broken due to the manufacturing process of a secondary battery or external shock.
상기 양극 활물질 전체 중량 대비, 상기 지르코늄 원소의 함량은 500 ppm 내지 9,000 ppm, 500 ppm 내지 8,000 ppm, 500 ppm 내지 7,000 ppm, 500 ppm 내지 6,000 ppm, 500 ppm 내지 5,000 ppm, 또는 500 ppm 내지 3,000 ppm으로 포함될 수 있다. 상기 범위를 만족하는 경우, 이차 전지의 기계적 특성 및 전기 전도도가 향상될 수 있어, 이차 전지의 장기 사용시 스웰링 현상이 저감될 수 있고, 수명 특성이 향상될 수 있다.Compared to the total weight of the positive electrode active material, the content of the zirconium element is 500 ppm to 9,000 ppm, 500 ppm to 8,000 ppm, 500 ppm to 7,000 ppm, 500 ppm to 6,000 ppm, 500 ppm to 5,000 ppm, or 500 ppm to 3,000 ppm. may be included. When the above range is satisfied, the mechanical properties and electrical conductivity of the secondary battery can be improved, the swelling phenomenon can be reduced during long-term use of the secondary battery, and the lifespan characteristics can be improved.
상기 리튬철 인산화물계 활물질 내에 질소(N) 원소가 도핑된 구조를 포함할 수 있다. 상기 질소 원소는 이차 전지의 전기 전도도를 향상시켜, 이차 전지의 초기 효율이 저하되는 현상이 최소화될 수 있다.The lithium iron phosphate-based active material may include a structure doped with a nitrogen (N) element. The nitrogen element improves the electrical conductivity of the secondary battery, thereby minimizing the decrease in initial efficiency of the secondary battery.
상기 양극 활물질 전체 중량 대비, 상기 질소 원소의 함량은 300 ppm 내지 10,000 ppm, 500 ppm 내지 5,000 ppm, 500 ppm 내지 4,000 ppm, 500 ppm 내지 3,000 ppm, 500 ppm 내지 2,000 ppm, 또는 500 ppm 내지 1,500 ppm으로 포함될 수 있다. 상기 범위를 만족하는 경우, 이차 전지의 전기 전도도가 향상되며, 초기 효율이 저하되는 현상이 최소화될 수 있다.Compared to the total weight of the positive electrode active material, the content of the nitrogen element is 300 ppm to 10,000 ppm, 500 ppm to 5,000 ppm, 500 ppm to 4,000 ppm, 500 ppm to 3,000 ppm, 500 ppm to 2,000 ppm, or 500 ppm to 1,500 ppm. may be included. When the above range is satisfied, the electrical conductivity of the secondary battery is improved, and the phenomenon of initial efficiency reduction can be minimized.
상기 리튬 인산화물계 활물질은 상기 코팅층 상에 형성된 전도성 코팅층을 포함할 수 있다. 상기 전도성 코팅층은 탄소계 물질을 포함할 수 있다. 상기 탄소계 물질은 카본 블랙, 탄소 섬유 또는 금속 섬유, 금속 분말, 도전성 위스커, 도전성 금속, 활성 카본(activated carbon) 폴리페닐렌 유도체, 천연 흑연, 인조 흑연, 슈퍼 피(Super-P), 아세틸렌 블랙, 케첸 블랙, 채널 블랙, 피네이스 블랙, 램프 블랙, 서머 블랙, 덴카 블랙, 알루미늄 분말, 니켈 분말, 산화아연, 티탄산 갈륨 및 산화 티탄으로 이루어진 군으로부터 선택된 1종 이상이 사용될 수 있다. The lithium phosphate-based active material may include a conductive coating layer formed on the coating layer. The conductive coating layer may include a carbon-based material. The carbon-based material includes carbon black, carbon fiber or metal fiber, metal powder, conductive whisker, conductive metal, activated carbon, polyphenylene derivative, natural graphite, artificial graphite, Super-P, and acetylene black. , Ketjen Black, Channel Black, Phineas Black, Lamp Black, Summer Black, Denka Black, aluminum powder, nickel powder, zinc oxide, gallium titanate, and titanium oxide may be used.
상기 전도성 코팅층의 두께는 1 nm 내지 500 nm, 1 nm 내지 300 nm, 1 nm 내지 250 nm, 1 nm 내지 200 nm, 5 nm 내지 200 nm, 5 nm 내지 100 nm, 또는 5 nm 내지 50 nm일 수 있다. 상기 범위를 만족하는 경우, 리튬 이온의 이동에 장애가 되지 않으며, 전기 전도도가 상승될 수 있다.The thickness of the conductive coating layer may be 1 nm to 500 nm, 1 nm to 300 nm, 1 nm to 250 nm, 1 nm to 200 nm, 5 nm to 200 nm, 5 nm to 100 nm, or 5 nm to 50 nm. there is. When the above range is satisfied, there is no obstacle to the movement of lithium ions, and electrical conductivity can be increased.
상기 전도성 코팅층에 포함된 탄소의 함량은 양극 활물질 총 중량 기준 1 중량% 내지 3 중량%, 1 중량% 내지 2.5 중량%, 1 중량% 내지 2 중량%일 수 있다. 상기 범위를 만족하는 경우, 전기 전도도 저하에 따른 저항 증가 문제를 야기하지 않으며, 양극 제조 시 양극 활물질이 탈리되는 현상을 최소화할 수 있다.The content of carbon included in the conductive coating layer may be 1% to 3% by weight, 1% to 2.5% by weight, or 1% to 2% by weight based on the total weight of the positive electrode active material. When the above range is satisfied, there is no problem of increased resistance due to a decrease in electrical conductivity, and the phenomenon of detachment of the positive electrode active material during production of the positive electrode can be minimized.
상기 양극 활물질의 평균 입경(D50)은 0.3㎛ 내지 10.0㎛, 0.3㎛ 내지 9.0㎛, 또는 0.6㎛ 내지 9.0㎛일 수 있다. 평균 입경(D50)은 양극 활물질 입경 분포의 50% 기준에서의 입경으로 정의할 수 있다. 또한, 평균 입경(D50)은 레이저 회절법(laser diffraction method)을 이용하여 측정할 수 있다. 상기 범위를 만족하는 경우, 도전재 및 바인더와 균일한 혼합이 가능하며, 공정 효율성이 증가될 수 있다.The average particle diameter (D 50 ) of the positive electrode active material may be 0.3 μm to 10.0 μm, 0.3 μm to 9.0 μm, or 0.6 μm to 9.0 μm. The average particle diameter (D 50 ) can be defined as the particle size based on 50% of the particle size distribution of the positive electrode active material. Additionally, the average particle diameter (D 50 ) can be measured using a laser diffraction method. When the above range is satisfied, uniform mixing with the conductive material and binder is possible, and process efficiency can be increased.
상기 양극 활물질의 비표면적(BET)은 30m2/g 이하, 20m2/g 이하, 또는 5m2/g 내지 15m2/g일 수 있다. 비표면적(BET)은 BEL Japan사의 BELSORP-mino II를 이용하여 액체 질소 온도 하(77K)에서의 질소가스 흡착량으로부터 산출할 수 있다. 상기 범위를 만족하는 경우, 양극 집전체와의 접착력 저하를 야기하지 않을 수 있다.The specific surface area (BET) of the positive electrode active material may be 30 m 2 /g or less, 20 m 2 /g or less, or 5 m 2 /g to 15 m 2 /g. Specific surface area (BET) can be calculated from the amount of nitrogen gas adsorption under liquid nitrogen temperature (77K) using BELSORP-mino II from BEL Japan. When the above range is satisfied, adhesion to the positive electrode current collector may not be reduced.
상기 양극 활물질의 탭 밀도(tap density)는 0.5g/cm3 이상, 0.6g/cm3 이상, 또는 0.6g/cm3 내지 1.5g/cm3일 수 있다. 탭밀도는 양극 활물질 분말의 겉보기 밀도를 의미하며, Seishin 社의 KYT-5000를 이용하여 측정할 수 있다. 상기 범위를 만족하는 경우, 양극의 충진밀도가 향상되어, 양극의 두께가 얇게 개선되며, 양극 활물질의 깨짐 현상을 개선할 수 있다.The tap density of the positive electrode active material is 0.5 g/cm 3 or more, 0.6 g/cm 3 or more, or 0.6 g/cm 3 or more. It may be 1.5g/cm 3 . Tap density refers to the apparent density of the positive electrode active material powder, and can be measured using Seishin's KYT-5000. When the above range is satisfied, the packing density of the positive electrode is improved, the thickness of the positive electrode can be improved to be thinner, and the cracking phenomenon of the positive electrode active material can be improved.
상기 양극 활물질은 바인더 및 도전재와 혼합되어 양극 집전체 상에 양극 활물질층으로 형성될 수 있다.The positive electrode active material may be mixed with a binder and a conductive material to form a positive electrode active material layer on the positive electrode current collector.
상기 바인더는 상기 양극 활물질 및 도전재 간의 결합력과 양극 활물질층 및 양극 집전체 간의 결합력을 향상시킬 수 있다. 바인더는 양극 활물질 100 중량부 기준 1 내지 30 중량부, 1 내지 20 중량부, 또는 1 내지 15 중량부로 첨가될 수 있다. 바인더의 종류는 특별히 제한되지 않으나, 예를 들어 폴리비닐리덴플로라이드(PVDF), 폴리테트라플루오로에틸렌(PTFE), 불소 고무, 스티렌 부타디엔 고무(SBR, 셀룰로오스계 수지 등을 사용할 수 있다.The binder can improve the bonding force between the positive electrode active material and the conductive material and the bonding force between the positive electrode active material layer and the positive electrode current collector. The binder may be added in an amount of 1 to 30 parts by weight, 1 to 20 parts by weight, or 1 to 15 parts by weight based on 100 parts by weight of the positive electrode active material. The type of binder is not particularly limited, but for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorine rubber, styrene butadiene rubber (SBR), cellulose resin, etc. can be used.
상기 도전재는 상기 양극 활물질의 도전성을 향상시킬 수 있다. 상기 도전재는 상기 양극 활물질 100 중량부 기준 1 내지 40 중량부, 1 내지 20 중량부, 또는 1 내지 10 중량부로 첨가될 수 있다. 상기 도전재의 종류는 특별히 제한되지 않으나, 예를 들어 슈퍼-비(Super-P), 흑연, 아세틸렌 블랙 등을 사용할 수 있다. The conductive material can improve the conductivity of the positive electrode active material. The conductive material may be added in an amount of 1 to 40 parts by weight, 1 to 20 parts by weight, or 1 to 10 parts by weight based on 100 parts by weight of the positive electrode active material. The type of the conductive material is not particularly limited, but for example, Super-P, graphite, acetylene black, etc. can be used.
상기 양극 집전체는 이차 전지에 화학적 변화를 유발하지 않으면서 높은 도전성을 가지는 것이라면 특별히 제한되지 않으며, 예를 들어 스테인레스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 또는 알루미늄이나 스테리인레스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면처리한 것 등을 사용할 수 있다. 상기 양극 집전체의 두께는 요구되는 제품에 따라 조절될 수 있고, 예를 들어 10㎛ 내지 500㎛, 10㎛ 내지 300㎛, 또는 20㎛ 내지 300㎛일 수 있다.The positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the secondary battery, for example, stainless steel, aluminum, nickel, titanium, fired carbon, or on the surface of aluminum or stainless steel. Those surface treated with carbon, nickel, titanium, silver, etc. can be used. The thickness of the positive electrode current collector may be adjusted depending on the required product, and may be, for example, 10 μm to 500 μm, 10 μm to 300 μm, or 20 μm to 300 μm.
상기 양극은 폴리아크릴아마이드(Polyacrylamide), 폴리우레탄(polyurethane), 및 폴리아크릴로나이트릴(polyacrylonitrile)로 이루어진 군에서 선택되는 1종 이상의 수평균 분자량 30,000 g/mol 내지 80,000 g/mol를 가지는 바인더 응집제를 포함할 수 있다. 상기 바인더 응집제는 상기 바인더의 분산성을 적절히 조절하여, 상기 집전체 상에 상기 바인더가 집중적으로 분포되어 전기 전도도가 저하되는 현상이 억제될 수 있다.The anode is a binder coagulant having a number average molecular weight of 30,000 g/mol to 80,000 g/mol of at least one type selected from the group consisting of polyacrylamide, polyurethane, and polyacrylonitrile. may include. The binder coagulant can appropriately control the dispersibility of the binder, thereby suppressing a phenomenon in which the binder is intensively distributed on the current collector, thereby reducing electrical conductivity.
본 발명에 따른 이차 전지는 양극, 음극, 상기 양극 및 음극 사이에 개재된 분리막을 포함하며, 상기 양극은 양극 활물질을 포함하며, 상기 양극 활물질은, 리튬철 인산화물계 활물질, 및 상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하며, 상기 코팅층은 나트륨(Na) 원소 및 탄탈륨(Ta) 원소를 포함하고, 상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며, 상기 코팅층에 포함된 상기 나트륨 원소:상기 탄탈륨 원소의 중량비는 1:0.1 내지 1:0.5이다.A secondary battery according to the present invention includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode includes a positive electrode active material, and the positive electrode active material includes a lithium iron phosphate-based active material and the lithium iron phosphate-based active material. It includes a coating layer formed on an active material, wherein the coating layer includes a sodium (Na) element and a tantalum (Ta) element, and relative to the total weight of the positive electrode active material, the total content of the sodium element and tantalum element is 500 ppm to 2,000 ppm. and the weight ratio of the sodium element and the tantalum element included in the coating layer is 1:0.1 to 1:0.5.
상기 이차 전지는 양극을 포함하며, 상기 양극은 전술한 양극과 관련하여 기재된 양극 활물질, 양극 집전체, 양극 활물질층 등과 동일하게 사용할 수 있다.The secondary battery includes a positive electrode, and the positive electrode can be used in the same manner as the positive electrode active material, positive electrode current collector, and positive electrode active material layer described in relation to the positive electrode described above.
상기 이차 전지는 본 발명의 양극 외에, 음극 및 분리막을 포함할 수 있다. 상기 음극은 음극 집전체 및 음극 집전체 상에 형성된 음극 활물질층을 포함할 수 있다. The secondary battery may include a negative electrode and a separator in addition to the positive electrode of the present invention. The negative electrode may include a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector.
상기 음극 집전체는 당해 이차 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 구리, 스테인레스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 구리나 스테인레스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면처리한 것, 알루미늄-카드뮴 합금 등이 사용될 수 있다. 또한, 표면에 미세한 요철을 형성하여 음극 활물질의 결합력을 강화시킬 수도 있으며, 필름, 시트, 호일, 네트, 다공질체, 발포체, 부직포체 등 다양한 형태로 사용될 수 있다.The negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the secondary battery, for example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, the surface of copper or stainless steel. Surface treatment with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the bonding power of the negative electrode active material can be strengthened by forming fine irregularities on the surface, and it can be used in various forms such as films, sheets, foils, nets, porous materials, foams, and non-woven fabrics.
상기 음극 활물질층은 음극 활물질을 포함할 수 있다. The negative electrode active material layer may include a negative electrode active material.
상기 음극 활물질의 종류는 특별히 제한되지 않으며, 통상 리튬의 가역적인 인터칼레이션 및 디인터칼레이션이 가능한 화합물이 사용될 수 있다. 예를 들어, 인조흑연, 천연흑연, 흑연화 탄소섬유, 비정질탄소, 고결정성 탄소 등의 탄소질 재료; Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si합금, Sn합금 또는 Al합금 등 리튬과 합금화가 가능한 금속질 화합물을 사용할 수 있다. 저결정성 탄소로는 연화탄소(soft carbon) 및 경화탄소(hard carbon)를 들 수 있으며, 고결정성 탄소로는 천연 흑연, 키시흑연(kish graphite), 열분해 탄소(pyrolytic carbon), 액정치피계 탄소섬유(mesophase pitch based carbon fiber), 탄소 미소구체(meso-carbon microbeads), 액정피치(mesophase pitches) 및 석유와 석탄계 코크스(petroleum or coal tar pitch derived cokes) 등의 고온 소성탄소를 들 수 있다. 음극 활물질은 필요에 따라 금속질 화합물과 탄소질 재료를 포함하는 복합물 등을 사용할 수도 있다. The type of the negative electrode active material is not particularly limited, and usually a compound capable of reversible intercalation and deintercalation of lithium can be used. For example, carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, and highly crystalline carbon; Metallic compounds that can be alloyed with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy, can be used. Low-crystalline carbon includes soft carbon and hard carbon, and high-crystalline carbon includes natural graphite, kish graphite, pyrolytic carbon, and liquid crystalline carbon. Examples include high-temperature calcined carbon such as mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches, and petroleum or coal tar pitch derived cokes. The negative electrode active material may be a composite containing a metallic compound and a carbonaceous material, if necessary.
바람직하게는, 상기 음극 활물질은 리튬 덴트라이드 발생을 억제하고, 상기 이차 전지의 수명 특성을 향상시키기 위해, 상기 음극 활물질은 니오비움(niobium)이 도핑된 티타늄-틴-옥사이드(titanium-tin-oxide) 및 상기 니오비움이 도핑된 티타늄-옥사이드(titanium-oxide)중 적어도 하나를 포함할 수 있다. Preferably, in order to suppress the generation of lithium dentride and improve the lifespan characteristics of the secondary battery, the negative electrode active material is titanium-tin-oxide doped with niobium. ) and the niobium-doped titanium-oxide (titanium-oxide).
상기 분리막은 음극 및 양극 사이에 개재될 수 있다. 상기 분리막은 음극과 양극 간 전기적 단락을 방지하고, 이온의 흐름이 발생되도록 구성된다. 상기 분리막은 다공성 고분자 필름 또는 다공성 부직포를 포함할 수 있다. 상기 다공성 고분자 필름은 에틸렌(ethylene) 중합체, 프로필렌(propylene) 중합체, 에틸렌/부텐(ethylene/butene) 공중합체, 에틸렌/헥센(ethylene/hexene) 공중합체, 및 에틸렌/메타크릴레이트(ethylene/methacrylate) 공중합체 등과 같은 폴리올레핀계 고분자를 포함한 단일층 혹은 다중층으로 구성될 수 있다. 상기 다공성 부직포는 고융점의 유리 섬유, 폴리에틸렌테레프탈레이트(polyethylene terephthalate) 섬유를 포함할 수 있다. 다만, 이에 한정되는 것이 아니며, 실시 형태에 따라 분리막은 세라믹(ceramic)을 포함한 고내열성 분리막(CCS; Ceramic Coated Separator)일 수 있다. The separator may be interposed between the cathode and the anode. The separator is configured to prevent electrical short-circuiting between the cathode and the anode and to generate a flow of ions. The separator may include a porous polymer film or a porous non-woven fabric. The porous polymer film includes ethylene polymer, propylene polymer, ethylene/butene copolymer, ethylene/hexene copolymer, and ethylene/methacrylate. It may be composed of a single layer or multiple layers containing polyolefin-based polymers such as copolymers. The porous nonwoven fabric may include high melting point glass fibers and polyethylene terephthalate (polyethylene terephthalate) fibers. However, it is not limited to this, and depending on the embodiment, the separator may be a highly heat-resistant separator (CCS; Ceramic Coated Separator) containing ceramic.
상기 양극, 음극 및 분리막은 권취(winding), 적층(lamination), 접음(folding), 또는 지그재그 스태킹(Zigzag stacking) 공정에 의해 전극 조립체로 제조될 수 있다. 상기 전극 조립체는 전해액과 함께 제공되어 본 발명에 따른 이차 전지로 제조될 수 있다. 상기 이차 전지는 캔을 사용한 원통형, 각형, 파우치(pouch)형, 및 코인(coin)형 중 어느 하나일 수 있으나, 이에 한정되는 것은 아니다.The anode, cathode, and separator may be manufactured into an electrode assembly by a winding, lamination, folding, or zigzag stacking process. The electrode assembly is provided with an electrolyte solution and can be manufactured into a secondary battery according to the present invention. The secondary battery may be any one of a cylindrical, prismatic, pouch, or coin type using a can, but is not limited thereto.
상기 전해액은 비수 전해액일 수 있다. 전해액은 리튬염과 유기 용매를 포함할 수 있다. 상기 유기 용매는 프로필렌 카보네이트(PC), 에틸렌 카보네이트(EC), 디에틸 카보네이트(DEC), 디메틸 카보네이트(DMC), 에틸메틸 카보네이트(EMC), 메틸프로필 카보네이트(MPC), 디프로필 카보네이트(DPC), 비닐렌 카보네이트(VC), 디메틸 설포사이드(dimethyl sulfoxide), 아세토니트릴(acetonitrile), 디메톡시에탄(dimethoxyethane), 디에톡시에탄(diethoxyethane), 설포란(sulfolane), 감마-부티로락톤(gamma-butyrolactone), 프로필렌 설파이드(propylene sulfide), 또는 테트라하이드로퓨란(tetrahydrofuran) 중 적어도 어느 하나를 포함할 수 있다.The electrolyte may be a non-aqueous electrolyte. The electrolyte solution may include a lithium salt and an organic solvent. The organic solvent includes propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC), dipropyl carbonate (DPC), Vinylene carbonate (VC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, gamma-butyrolactone ), propylene sulfide, or tetrahydrofuran.
이하에서, 실시예 및 비교예를 바탕으로 본 발명을 더욱 구체적으로 설명한다. 다만, 다음의 실시예 및 비교예는 본 발명을 더욱 상세히 설명하기 위한 예시일 뿐, 본 발명이 다음의 실시예 및 비교예에 의해 한정되는 것은 아니다.Below, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are only examples to explain the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.
실시예Example
실시예 1Example 1
<양극 활물질 제조><Manufacture of positive electrode active material>
황산철(FeSO4ㆍ7H2O) 0.5 mol, 인산(H3PO4) 0.6 mol, 및 산화 방지제를 포함한 황산철 수용액과 리튬 수용액(LiOHㆍH2O) 2.0 mol의 혼합물에 pH 6이 되도록 암모니아수를 첨가하여 양극 슬러리를 제조하였다. 이후, 연속 공정 초임계 반응기에서 400 ℃ 및 270 bar의 조건하에 상기 양극 슬러리를 일정 속도로 투입하여 LiFePO4 용액을 제조하였으며, LiFePO4 용액을 수세 및 여과하여 LiFePO4 입자를 수득하였다. 상기 LiFePO4 입자와 코팅 물질로서 Na2CO3 및 Ta2O5을 혼합한 후, 700 ℃에서 5시간 동안 열처리하여 양극 활물질을 제조하였으며, 상기 LiFePO4 입자에 코팅된 Na 및 Ta의 함량, 상기 Na 및 Ta의 중량비는 하기 표 1에 나타내었다.Add 0.5 mol of iron sulfate (FeSO 4 ㆍ7H 2 O), 0.6 mol of phosphoric acid (H 3 PO 4 ), and 2.0 mol of aqueous iron sulfate and lithium aqueous solution (LiOH ㆍH 2 O) containing antioxidants to pH 6. A positive electrode slurry was prepared by adding ammonia water. Afterwards, a LiFePO 4 solution was prepared by adding the positive electrode slurry at a constant rate under the conditions of 400° C. and 270 bar in a continuous process supercritical reactor, and the LiFePO 4 solution was washed and filtered to obtain LiFePO 4 particles. The LiFePO 4 particles were mixed with Na 2 CO 3 and Ta 2 O 5 as a coating material, and then heat-treated at 700° C. for 5 hours to prepare a positive electrode active material. The contents of Na and Ta coated on the LiFePO 4 particles were as follows: The weight ratio of Na and Ta is shown in Table 1 below.
실시예 2Example 2
상기 실시예 1에서 제조된 양극 활물질을 슬러리화한 후, 상기 슬러리 총 중량 기준 탄소계 물질을 1 중량% 첨가하여 분무 건조하였다. 이후, 불활성 분위기에서 800 ℃에서 3시간 동안 열처리하여 상기 양극 활물질 표면에 탄소 코팅층이 형성된 양극 활물질을 제조하였다.After slurrying the positive electrode active material prepared in Example 1, 1% by weight of a carbon-based material based on the total weight of the slurry was added and spray dried. Thereafter, a positive electrode active material with a carbon coating layer formed on the surface of the positive active material was prepared by heat treatment at 800° C. for 3 hours in an inert atmosphere.
실시예 3 내지 6Examples 3 to 6
상기 실시예 1과 동일한 공정에 의해 양극 활물질을 제조하였으며, 상기 LiFePO4 입자에 코팅된 Na 및 Ta의 함량, 상기 Na 및 Ta의 중량비는 하기 표 1에 나타내었다.A positive electrode active material was manufactured through the same process as Example 1, and the contents of Na and Ta coated on the LiFePO 4 particles and the weight ratio of Na and Ta are shown in Table 1 below.
비교예 1Comparative Example 1
상기 실시예 1에서 제조된 LiFePO4 입자를 양극 활물질로 사용하였다.LiFePO 4 particles prepared in Example 1 were used as a positive electrode active material.
비교예 2Comparative Example 2
상기 실시예 1에서 제조된 LiFePO4 입자와 코팅 물질로서 Na2CO3를 혼합한 후, 700 ℃에서 5시간 동안 열처리하여 양극 활물질을 제조하였으며, 상기 LiFePO4 입자에 코팅된 Na의 함량은 하기 표 1에 나타내었다.After mixing the LiFePO 4 particles prepared in Example 1 with Na 2 CO 3 as a coating material, a positive electrode active material was prepared by heat treatment at 700° C. for 5 hours. The content of Na coated on the LiFePO 4 particles is shown in the table below. It is shown in 1.
비교예 3Comparative Example 3
상기 실시예 1에서 제조된 LiFePO4 입자와 코팅 물질로서 Ta2O5을 혼합한 후, 700 ℃에서 5시간 동안 열처리하여 양극 활물질을 제조하였으며, 상기 LiFePO4 입자에 코팅된 Ta의 함량은 하기 표 1에 나타내었다.After mixing the LiFePO 4 particles prepared in Example 1 with Ta 2 O 5 as a coating material, a positive electrode active material was prepared by heat treatment at 700° C. for 5 hours. The content of Ta coated on the LiFePO 4 particles is shown in the table below. It is shown in 1.
비교예 4 내지 8Comparative Examples 4 to 8
상기 실시예 1과 동일한 공정에 의해 양극 활물질을 제조하였으며, 상기 LiFePO4 입자에 코팅된 Na 및 Ta의 함량, 상기 Na 및 Ta의 중량비는 하기 표 1에 나타내었다.A positive electrode active material was manufactured through the same process as Example 1, and the contents of Na and Ta coated on the LiFePO 4 particles and the weight ratio of Na and Ta are shown in Table 1 below.
형성 여부coating layer
Formed or not
2) Ta: 양극 활물질 전체 중량 대비 코팅층에 포함된 Ta의 원소 함량
3) 전체 함량: 양극 활물질 전체 중량 대비 코팅층에 포함된 Na 및 Ta의 원소 함량1) Na: Elemental content of Na contained in the coating layer compared to the total weight of the positive electrode active material
2) Ta: Elemental content of Ta contained in the coating layer compared to the total weight of the positive electrode active material
3) Total content: Elemental content of Na and Ta contained in the coating layer compared to the total weight of the positive electrode active material.
실험예Experiment example
실시예 1 내지 6Examples 1 to 6
<음극 제조><Cathode manufacturing>
TiNb2O7(TNO) 음극 활물질, 아세틸렌 블랙, 폴리비닐리덴플로오라이드를 90:5:5의 중량비로 N-메틸 피롤리돈 용매 중에서 혼합하여 음극 활물질 슬러리를 제조하였다. 이후, 음극 활물질 슬러리를 10 ㎛ 두께의 구리(Cu) 포일 위에 코팅하고, 110 ℃에서 건조한 후, 압연(press)하여 음극을 제조하였다.TiNb 2 O 7 (TNO) negative electrode active material, acetylene black, and polyvinylidene fluoride were mixed in N-methyl pyrrolidone solvent at a weight ratio of 90:5:5 to prepare a negative electrode active material slurry. Afterwards, the negative electrode active material slurry was coated on a 10 ㎛ thick copper (Cu) foil, dried at 110°C, and then pressed to produce a negative electrode.
<양극 제조><Anode manufacturing>
상기 실시예 1 내지 6에서 제조된 각각의 양극 활물질, Super-P, 폴리비닐리덴플로오라이드를 95:2.5:2.5의 중량비로 N-메틸 피롤리돈 용매 중에서 혼합하여 양극 활물질 슬러리를 제조하였다. 이후, 양극 활물질 슬러리를 15 ㎛ 두께의 알루미늄(Al) 포일 위에 코팅하고, 120 ℃에서 건조한 후, 압연(press)하여 양극을 제조하였다.A positive electrode active material slurry was prepared by mixing each of the positive electrode active materials, Super-P, and polyvinylidene fluoride prepared in Examples 1 to 6 in N-methyl pyrrolidone solvent at a weight ratio of 95:2.5:2.5. Afterwards, the positive electrode active material slurry was coated on a 15 ㎛ thick aluminum (Al) foil, dried at 120°C, and then rolled to produce a positive electrode.
<이차 전지 제조><Secondary battery manufacturing>
상기 음극과 양극 사이에 두께 25 ㎛의 폴리에틸렌 소재의 분리막을 개재하여 전극 조립체를 제조한 후, 상기 전극 조립체를 케이스에 수납하고, 케이스 내부에 에틸렌 카보네이트:메틸에틸카보네이트가 2:1의 부피비로 혼합된 용매에 LiPF6 1M 및 비닐카보네이트 2.5 중량%로 혼합된 전해액을 투입하여 이차 전지를 제조하였다.After manufacturing the electrode assembly by interposing a separator made of polyethylene with a thickness of 25 μm between the cathode and the anode, the electrode assembly is stored in a case, and ethylene carbonate:methylethyl carbonate is mixed at a volume ratio of 2:1 inside the case. A secondary battery was manufactured by adding an electrolyte solution mixed with 1M LiPF 6 and 2.5% by weight of vinyl carbonate to the solvent.
비교예 1 내지 8Comparative Examples 1 to 8
TiNb2O7(TNO) 음극 활물질 대신 탄소계 음극 활물질을 사용하는 것을 제외하고는 상기 음극, 양극, 및 이차 전지 제조 공정과 동일하게 이차 전지를 제조하였다.A secondary battery was manufactured in the same manner as the above negative electrode, positive electrode, and secondary battery manufacturing processes, except that a carbon-based negative electrode active material was used instead of the TiNb 2 O 7 (TNO) negative electrode active material.
실험예 1 - 고율 특성 평가Experimental Example 1 - High rate characteristic evaluation
상기 실시예 1 내지 6 및 비교예 1 내지 8에서 제조된 각각의 양극 활물질을 사용하여 제조된 각각의 이차 전지를 상온에서 리튬 금속 대비 2.5V 내지 4.1V의 전압 범위에서 0.1C rate의 정전류로 충전시키면서, 방전시의 전류밀도가 증가함에 따른 방전용량을 얻고 이로부터 율별 충방전 효율을 계산하였다. 방전시의 전류밀도는 각각 0.1C, 0.2C, 0.5C, 1C 및 2C rate였다. 2C에서의 충방전 효율은 하기 식 1에 의해 계산하였으며, 그 결과를 하기 표 2에 나타내었다.Each secondary battery manufactured using each of the positive electrode active materials prepared in Examples 1 to 6 and Comparative Examples 1 to 8 was charged at a constant current of 0.1C rate in a voltage range of 2.5V to 4.1V relative to lithium metal at room temperature. While doing so, the discharge capacity was obtained as the current density during discharge increased, and the charge/discharge efficiency for each rate was calculated from this. The current densities during discharge were 0.1C, 0.2C, 0.5C, 1C, and 2C rates, respectively. The charge/discharge efficiency at 2C was calculated using Equation 1 below, and the results are shown in Table 2 below.
[식 1][Equation 1]
2C에서의 충방전 효율(%)=[2C 방전용량/0.1C 충전용량]Х100Charge/discharge efficiency at 2C (%)=[2C discharge capacity/0.1C charge capacity]Х100
실험예 2 - 수명 특성 평가Experimental Example 2 - Evaluation of lifespan characteristics
상기 실시예 1 내지 6 및 비교예 1 내지 8에서 제조된 각각의 양극 활물질을 사용하여 제조된 각각의 이차 전지를 상온에서 리튬 금속 대비 2.5V 내지 4.1V의 전압 범위에서 1C rate의 정전류로 충방전시키면서 용량유지율 및 500번째 사이클에서의 방전용량을 측정하였다. 상온에서 용량유지율은 하기 식 2에 의해 계산하였으며, 그 결과를 하기 표 2에 나타내었다.Each secondary battery manufactured using each of the positive electrode active materials prepared in Examples 1 to 6 and Comparative Examples 1 to 8 was charged and discharged at a constant current of 1C rate in a voltage range of 2.5V to 4.1V relative to lithium metal at room temperature. While doing so, the capacity maintenance rate and discharge capacity at the 500th cycle were measured. The capacity retention rate at room temperature was calculated using Equation 2 below, and the results are shown in Table 2 below.
[식 2][Equation 2]
용량유지율(%) = [500번째 사이클에서의 방전용량/1번째 사이클에서의 방전용량]Х100Capacity maintenance rate (%) = [discharge capacity at 500th cycle/discharge capacity at 1st cycle]Х100
충족
여부1) A condition
satisfy
Whether 1)
충족
여부2) B condition
satisfy
2) Whether
충족
여부3) C condition
satisfy
3) Whether
충방전 효율(%)in 2C
Charge/discharge efficiency (%)
유지율
(%)Volume
retention rate
(%)
(mAh/g)Discharge capacity at 500th cycle
(mAh/g)
2) B 조건 충족 여부: Na 및 Ta 원소의 전체 함량 500 ppm ~ 2,000 ppm 해당 여부
3) C 조건 충족 여부: 코팅층에 포함된 Na:Ta의 중량비 1:0.1~0.5 해당 여부1) Whether condition A is met: Whether or not a coating layer containing Na and Ta elements is formed
2) Whether condition B is met: Whether the total content of Na and Ta elements is 500 ppm ~ 2,000 ppm
3) Whether condition C is met: Whether the weight ratio of Na:Ta contained in the coating layer is 1:0.1~0.5
상기 표 1 내지 2에서 확인할 수 있는 바와 같이, 리튬철 인산화물계 활물질에 나트륨 및 탄탈륨 원소가 코팅되며, 상기 나트륨 및 탄탈륨 원소의 함량 및, 상기 나트륨 및 탄탈륨 원소 간의 중량비가 특정 조건을 충족하도록 제조된 양극 활물질을 포함하는 실시예 1 내지 6은 비교예 1 내지 8 대비 고율 특성이 우수하여, 방전속도(C-rate)의 증가에 따른 용량 유지율이 우수한 것을 확인할 수 있었다. 또한, 실시예 1 내지 6은 비교예 1 내지 8 대비 수명 특성 및 방전 용량이 현저히 향상된 것을 확인할 수 있었다. 즉, 본 발명에 따른 양극 활물질을 포함하는 실시예 1 내지 6은 고율 특성이 우수한 동시에 수명 특성 및 방전 용량도 향상된 것을 확인할 수 있었다.As can be seen in Tables 1 and 2, sodium and tantalum elements are coated on a lithium iron phosphate-based active material, and the content of the sodium and tantalum elements and the weight ratio between the sodium and tantalum elements are manufactured to meet specific conditions. It was confirmed that Examples 1 to 6 containing the positive electrode active material had superior high rate characteristics compared to Comparative Examples 1 to 8, and thus had excellent capacity retention rate with increase in discharge rate (C-rate). In addition, it was confirmed that Examples 1 to 6 had significantly improved lifespan characteristics and discharge capacity compared to Comparative Examples 1 to 8. That is, it was confirmed that Examples 1 to 6 containing the positive electrode active material according to the present invention had excellent high rate characteristics and improved lifespan characteristics and discharge capacity.
Claims (5)
상기 양극은 양극 활물질을 포함하며,
상기 양극 활물질은,
리튬철 인산화물계 활물질; 및
상기 리튬철 인산화물계 활물질 상에 형성된 코팅층을 포함하며,
상기 코팅층은 Na2CO3로부터 유래된 나트륨(Na) 원소 및 Ta2O5로부터 유래된 탄탈륨(Ta) 원소를 포함하고,
상기 양극 활물질 전체 중량 대비, 상기 나트륨 원소 및 탄탈륨 원소의 전체 함량은 500 ppm 내지 2,000 ppm으로 포함되며,
상기 코팅층에 포함된 상기 나트륨 원소:상기 탄탈륨 원소의 중량비는 1:0.1이고,
상기 양극 활물질 표면에 탄소 코팅층이 형성되며,
상기 양극 활물질은 양극 슬러리로부터 제조되고,
상기 양극 슬러리 총 중량 기준 탄소계 물질이 1 중량% 첨가되어 분무 건조된 후, 불활성 분위기에서 800 ℃에서 3시간 동안 열처리하여 상기 양극 활물질 표면에 상기 탄소계 물질로부터 유래된 상기 탄소 코팅층이 형성되며,
상기 음극은 음극 활물질을 포함하는 음극 활물질층을 포함하고, 상기 음극 활물질은 TiNb2O7 인 이차 전지.A secondary battery comprising an anode, a cathode, and a separator interposed between the anode and the cathode,
The positive electrode includes a positive electrode active material,
The positive electrode active material is,
Lithium iron phosphate-based active materials; and
It includes a coating layer formed on the lithium iron phosphate-based active material,
The coating layer includes a sodium (Na) element derived from Na 2 CO 3 and a tantalum (Ta) element derived from Ta 2 O 5 ,
Compared to the total weight of the positive electrode active material, the total content of the sodium element and tantalum element is included in 500 ppm to 2,000 ppm,
The weight ratio of the sodium element to the tantalum element contained in the coating layer is 1:0.1,
A carbon coating layer is formed on the surface of the positive electrode active material,
The positive electrode active material is manufactured from positive electrode slurry,
1% by weight of a carbon-based material based on the total weight of the positive electrode slurry is added and spray-dried, and then heat-treated at 800° C. for 3 hours in an inert atmosphere to form the carbon coating layer derived from the carbon-based material on the surface of the positive electrode active material,
A secondary battery wherein the negative electrode includes a negative electrode active material layer containing a negative electrode active material, and the negative electrode active material is TiNb 2 O 7 .
상기 코팅층은 알루미늄(Al) 원소를 포함하는 것인 이차 전지.According to paragraph 1,
A secondary battery wherein the coating layer contains an aluminum (Al) element.
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| KR20170063372A (en) * | 2015-11-30 | 2017-06-08 | 주식회사 엘지화학 | Negative electroed active material comprising titanium based composite, method thereof and lithium secondary battery comprising the same |
| JP2019216047A (en) * | 2018-06-14 | 2019-12-19 | 東洋インキＳｃホールディングス株式会社 | Composition for porous electrode, the porous electrode, and battery using the same |
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| KR20170063372A (en) * | 2015-11-30 | 2017-06-08 | 주식회사 엘지화학 | Negative electroed active material comprising titanium based composite, method thereof and lithium secondary battery comprising the same |
| JP2019216047A (en) * | 2018-06-14 | 2019-12-19 | 東洋インキＳｃホールディングス株式会社 | Composition for porous electrode, the porous electrode, and battery using the same |
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