JP2022095988A - Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery - Google Patents
Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery Download PDFInfo
- Publication number
- JP2022095988A JP2022095988A JP2022071967A JP2022071967A JP2022095988A JP 2022095988 A JP2022095988 A JP 2022095988A JP 2022071967 A JP2022071967 A JP 2022071967A JP 2022071967 A JP2022071967 A JP 2022071967A JP 2022095988 A JP2022095988 A JP 2022095988A
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- lithium
- active material
- electrode active
- secondary battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000007774 positive electrode material Substances 0.000 title claims abstract description 122
- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 37
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims abstract description 130
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 65
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 61
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 10
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 6
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 6
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 6
- 239000002131 composite material Substances 0.000 claims description 41
- RSNHXDVSISOZOB-UHFFFAOYSA-N lithium nickel Chemical compound [Li].[Ni] RSNHXDVSISOZOB-UHFFFAOYSA-N 0.000 claims description 30
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 22
- 229910014211 My O Inorganic materials 0.000 claims description 4
- 229910017698 Ni 1-x-y Co Inorganic materials 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 23
- 238000001879 gelation Methods 0.000 abstract description 11
- 229910052748 manganese Inorganic materials 0.000 abstract description 5
- 229910013402 LizNi1-x-yCoxMyO2 Inorganic materials 0.000 abstract 1
- 229910021440 lithium nickel complex oxide Inorganic materials 0.000 abstract 1
- 230000001629 suppression Effects 0.000 abstract 1
- 239000000843 powder Substances 0.000 description 62
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 35
- 229910052744 lithium Inorganic materials 0.000 description 34
- 238000004519 manufacturing process Methods 0.000 description 31
- 239000007864 aqueous solution Substances 0.000 description 29
- 239000002002 slurry Substances 0.000 description 26
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 24
- 238000000034 method Methods 0.000 description 24
- 238000011156 evaluation Methods 0.000 description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 20
- 238000005406 washing Methods 0.000 description 19
- 229910052759 nickel Inorganic materials 0.000 description 18
- 239000000463 material Substances 0.000 description 15
- 239000002245 particle Substances 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 238000001035 drying Methods 0.000 description 13
- 238000004140 cleaning Methods 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 10
- 239000012298 atmosphere Substances 0.000 description 10
- 229910052799 carbon Inorganic materials 0.000 description 10
- 229910001416 lithium ion Inorganic materials 0.000 description 10
- -1 and the like Substances 0.000 description 9
- 239000008151 electrolyte solution Substances 0.000 description 9
- 238000002156 mixing Methods 0.000 description 9
- 239000002585 base Substances 0.000 description 8
- 229910017052 cobalt Inorganic materials 0.000 description 8
- 239000010941 cobalt Substances 0.000 description 8
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 7
- 239000011230 binding agent Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 7
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Inorganic materials [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000002904 solvent Substances 0.000 description 7
- 229910052717 sulfur Inorganic materials 0.000 description 7
- 239000011593 sulfur Substances 0.000 description 7
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 6
- 239000002905 metal composite material Substances 0.000 description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 5
- CKFRRHLHAJZIIN-UHFFFAOYSA-N cobalt lithium Chemical compound [Li].[Co] CKFRRHLHAJZIIN-UHFFFAOYSA-N 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 238000006386 neutralization reaction Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
- 230000002427 irreversible effect Effects 0.000 description 4
- 229910003002 lithium salt Inorganic materials 0.000 description 4
- 159000000002 lithium salts Chemical class 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 239000007773 negative electrode material Substances 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 3
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 150000002642 lithium compounds Chemical class 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000004438 BET method Methods 0.000 description 2
- 229910013684 LiClO 4 Inorganic materials 0.000 description 2
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000006230 acetylene black Substances 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000003631 expected effect Effects 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 2
- 229910021382 natural graphite Inorganic materials 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000006479 redox reaction Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 150000003464 sulfur compounds Chemical class 0.000 description 2
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- YBJCDTIWNDBNTM-UHFFFAOYSA-N 1-methylsulfonylethane Chemical compound CCS(C)(=O)=O YBJCDTIWNDBNTM-UHFFFAOYSA-N 0.000 description 1
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- YEVQZPWSVWZAOB-UHFFFAOYSA-N 2-(bromomethyl)-1-iodo-4-(trifluoromethyl)benzene Chemical compound FC(F)(F)C1=CC=C(I)C(CBr)=C1 YEVQZPWSVWZAOB-UHFFFAOYSA-N 0.000 description 1
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 description 1
- GKZFQPGIDVGTLZ-UHFFFAOYSA-N 4-(trifluoromethyl)-1,3-dioxolan-2-one Chemical compound FC(F)(F)C1COC(=O)O1 GKZFQPGIDVGTLZ-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- 229920006369 KF polymer Polymers 0.000 description 1
- 229910000733 Li alloy Inorganic materials 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910013131 LiN Inorganic materials 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910001228 Li[Ni1/3Co1/3Mn1/3]O2 (NCM 111) Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- KLARSDUHONHPRF-UHFFFAOYSA-N [Li].[Mn] Chemical compound [Li].[Mn] KLARSDUHONHPRF-UHFFFAOYSA-N 0.000 description 1
- SOXUFMZTHZXOGC-UHFFFAOYSA-N [Li].[Mn].[Co].[Ni] Chemical compound [Li].[Mn].[Co].[Ni] SOXUFMZTHZXOGC-UHFFFAOYSA-N 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 150000005678 chain carbonates Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001869 cobalt compounds Chemical class 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 150000005676 cyclic carbonates Chemical class 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- VUPKGFBOKBGHFZ-UHFFFAOYSA-N dipropyl carbonate Chemical compound CCCOC(=O)OCCC VUPKGFBOKBGHFZ-UHFFFAOYSA-N 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 229920001973 fluoroelastomer Polymers 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 239000001989 lithium alloy Substances 0.000 description 1
- 229910000032 lithium hydrogen carbonate Inorganic materials 0.000 description 1
- HQRPHMAXFVUBJX-UHFFFAOYSA-M lithium;hydrogen carbonate Chemical compound [Li+].OC([O-])=O HQRPHMAXFVUBJX-UHFFFAOYSA-M 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 239000008239 natural water Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 150000003018 phosphorus compounds Chemical class 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Images
Classifications
-
- 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
Abstract
Description
本発明は、非水系電解質二次電池用正極活物質、および非水系電解質二次電池に関する。 The present invention relates to a positive electrode active material for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery.
近年、携帯電話やノート型パソコンなどの携帯電子機器の普及に伴い、高いエネルギー密度を有する小型で軽量な非水系電解質二次電池の開発が要求されている。また、ハイブリッド自動車を始めとする電気自動車用の電池として、高出力の非水系電解質二次電池の開発が要求されている。このような要求を満たす非水系電解質二次電池として、リチウムイオン二次電池がある。リチウムイオン二次電池は、負極、正極、電解液などで構成され、負極および正極の活物質には、リチウムイオンを脱離および挿入することが可能な材料が用いられている。 In recent years, with the spread of portable electronic devices such as mobile phones and notebook computers, there is a demand for the development of small and lightweight non-aqueous electrolyte secondary batteries having high energy density. Further, as a battery for electric vehicles such as hybrid vehicles, development of a high-output non-aqueous electrolyte secondary battery is required. As a non-aqueous electrolyte secondary battery satisfying such a requirement, there is a lithium ion secondary battery. The lithium ion secondary battery is composed of a negative electrode, a positive electrode, an electrolytic solution, and the like, and a material capable of desorbing and inserting lithium ions is used as the active material of the negative electrode and the positive electrode.
リチウムイオン二次電池については、現在、研究開発が盛んに行われているところである。中でも、層状またはスピネル型のリチウム金属複合酸化物を正極活物質に用いたリチウムイオン二次電池は、４Ｖ級の高い電圧が得られるため、高いエネルギー密度を有する電池として実用化が進んでいる。これまで主に提案されているリチウム金属複合酸化物としては、合成が比較的容易なリチウムコバルト複合酸化物（例えば、ＬｉＣｏＯ２）や、コバルトよりも安価なニッケルを用いたリチウムニッケル複合酸化物（例えば、ＬｉＮｉＯ２）、リチウムニッケルコバルトマンガン複合酸化物（例えば、ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２）、リチウムマンガン複合酸化物（例えば、ＬｉＭｎ２Ｏ４）などが挙げられる。 Currently, research and development of lithium-ion secondary batteries is being actively carried out. Among them, a lithium ion secondary battery using a layered or spinel type lithium metal composite oxide as a positive electrode active material is being put into practical use as a battery having a high energy density because a high voltage of 4V class can be obtained. Lithium metal composite oxides that have been mainly proposed so far include lithium cobalt composite oxides that are relatively easy to synthesize (for example, LiCoO 2 ) and lithium nickel composite oxides that use nickel, which is cheaper than cobalt (for example, LiCoO 2). For example, LiNiO 2 ), lithium nickel cobalt manganese composite oxide (for example, LiNi 1/3 Co 1/3 Mn 1/3 O 2 ), lithium manganese composite oxide (for example, LiMn 2 O 4 ) and the like can be mentioned.
リチウムコバルト複合酸化物を正極活物質として用いた電池は、優れた初期容量特性やサイクル特性を得るための開発がこれまで数多く行われてきており、すでにさまざまな成果が得られている。しかし、リチウムコバルト複合酸化物は、原料に高価なコバルト化合物が用いられる。このため、リチウムコバルト複合酸化物は、これを用いた電池の容量あたりの単価がニッケル水素電池より大幅に高く、正極活物質として適用可能な用途はかなり限定される。したがって、携帯機器用の小型二次電池についてだけではなく、電力貯蔵用や電気自動車用などの大型二次電池についても、正極活物質のコストを下げ、より安価なリチウムイオン二次電池の製造を可能とすることに対する期待は大きく、その実現は、工業的に大きな意義があるといえる。 Batteries using lithium cobalt composite oxide as a positive electrode active material have been developed in large numbers to obtain excellent initial capacity characteristics and cycle characteristics, and various results have already been obtained. However, as the lithium cobalt composite oxide, an expensive cobalt compound is used as a raw material. Therefore, the unit price per capacity of the battery using the lithium cobalt composite oxide is significantly higher than that of the nickel-metal hydride battery, and the application as a positive electrode active material is considerably limited. Therefore, not only for small secondary batteries for portable devices, but also for large secondary batteries for power storage and electric vehicles, we can reduce the cost of positive electrode active materials and manufacture cheaper lithium-ion secondary batteries. There are great expectations for what will be possible, and it can be said that its realization has great industrial significance.
コバルトよりも安価なニッケルを用いたリチウムニッケル複合酸化物は、リチウムコバルト複合酸化物よりも低い電気化学ポテンシャルを示すため、電解液の酸化による分解が問題になりにくく、より高容量が期待でき、また、コバルト系と同様に高い電池電圧を示すことから、開発が盛んに行われている。しかし、純粋にニッケルのみで合成したリチウムニッケル複合酸化物は、正極活物質としてリチウムイオン二次電池を作製した場合、コバルト系と比較してサイクル特性が劣り、また、高温環境下で使用や保存により比較的電池性能を損ないやすいという欠点を有する。そのため、例えば特許文献１に開示されるように、ニッケルの一部をコバルトやアルミニウムで置換したリチウムニッケル複合酸化物が一般的に知られている。 Lithium-nickel composite oxide using nickel, which is cheaper than cobalt, shows lower electrochemical potential than lithium-cobalt composite oxide, so decomposition by oxidation of the electrolytic solution is less likely to be a problem, and higher capacity can be expected. In addition, it is being actively developed because it exhibits a high battery voltage similar to that of cobalt. However, the lithium-nickel composite oxide synthesized purely from nickel is inferior in cycle characteristics to the cobalt-based battery when a lithium-ion secondary battery is manufactured as a positive electrode active material, and is used or stored in a high-temperature environment. This has the disadvantage that the battery performance is relatively easily impaired. Therefore, for example, as disclosed in Patent Document 1, a lithium nickel composite oxide in which a part of nickel is replaced with cobalt or aluminum is generally known.
正極活物質であるリチウムニッケル複合酸化物の一般的な製造方法としては、中和晶析法により前駆体であるニッケル複合水酸化物を作製し、この前駆体を水酸化リチウムなどのリチウム化合物と混合して焼成し、リチウムニッケル複合酸化物を得る方法が知られている。しかしながら、この方法で合成したリチウムニッケル複合酸化物には未反応の水酸化リチウムや、未反応の水酸化リチウムが炭酸化して生じる炭酸リチウム、および原料由来の不純物から生じた硫酸リチウム等が残留している。 As a general method for producing a lithium nickel composite oxide as a positive electrode active material, a nickel composite hydroxide as a precursor is prepared by a neutralization crystallization method, and this precursor is combined with a lithium compound such as lithium hydroxide. A method of mixing and firing to obtain a lithium nickel composite oxide is known. However, unreacted lithium hydroxide, unreacted lithium hydroxide generated by carbonation of lithium hydroxide, lithium sulfate generated from impurities derived from raw materials, and the like remain in the lithium-nickel composite oxide synthesized by this method. ing.
未反応の水酸化リチウムは、正極活物質を正極合材ペーストに混練する際に、正極合材ペーストのゲル化を引き起こす原因になる。さらに、未反応の水酸化リチウムは、正極活物質が高温環境下で充電される場合、水酸化リチウムが酸化分解しガス発生を引き起こす要因にもなる。一方、原料由来の不純物から生じる硫酸リチウムは充放電反応に寄与しないため、電池を構成する際、正極活物質の不可逆容量に相当する分、負極材料を余計に電池に使用せざるを負えない。その結果、電池全体としての重量当たり及び体積当たりの容量が小さくなる上、不可逆容量として負極に蓄積された余分なリチウムは安全性の面からも問題となる。 Unreacted lithium hydroxide causes gelation of the positive electrode mixture paste when the positive electrode active material is kneaded into the positive electrode mixture paste. Further, unreacted lithium hydroxide also becomes a factor that oxidatively decomposes lithium hydroxide and causes gas generation when the positive electrode active material is charged in a high temperature environment. On the other hand, since lithium sulfate generated from impurities derived from raw materials does not contribute to the charge / discharge reaction, when constructing a battery, it is inevitable to use an extra negative electrode material for the battery as much as the irreversible capacity of the positive electrode active material. As a result, the capacity per weight and volume of the battery as a whole becomes small, and the excess lithium accumulated in the negative electrode as an irreversible capacity poses a problem in terms of safety.
そこで、特許文献２によれば合成後のリチウムニッケル複合酸化物に自然水を加えて攪拌し、水酸化リチウム、および硫酸リチウムなど（以下、リチウム塩と総称する）を除去する方法が提案されている。しかしながら、この方法により得られた正極活物質は、水洗中にリチウムニッケル複合酸化物表面近傍のリチウムイオンが失われている。そのため、耐候性が低下し、正極活物質を通常の水分や炭酸ガスを含む大気雰囲気下で取り扱った際に、結晶内部からリチウムイオンが引き抜かれ、電池とした際に容量が低下する問題がある。
Therefore, according to
そこで、特許文献３によれば合成後のリチウムニッケル複合酸化物を、ＣＯ２濃度が０．１体積％以上で、かつ露点が－１５℃以下である雰囲気中で、この雰囲気温度を１５０℃以下としてガス処理することで、リチウムニッケル複合酸化物に残存する水酸化リチウムを炭酸化し、炭酸リチウムとすることで高温環境下での保存特性を高める方法が提案されている。しかしながら、この方法では未反応の水酸化リチウムを十分に除去することが難しく、さらに硫酸リチウムの除去については記載されていない。
Therefore, according to
本発明の目的はこのような問題に鑑みて、正極合材ペーストのゲル化を抑制し、かつ、耐候性に優れた非水系電解質二次電池用正極活物質を提供することを目的とする。 In view of such problems, an object of the present invention is to provide a positive electrode active material for a non-aqueous electrolyte secondary battery, which suppresses gelation of a positive electrode mixture paste and has excellent weather resistance.
本発明者らは、上記課題を解決するため、非水系電解質二次電池用正極活物質として用いられているリチウム金属複合酸化物およびその製造方法に関して鋭意研究を重ねた結果、リチウムニッケル複合酸化物からなる粉末を、炭酸リチウム水溶液で洗浄することによって、過度のリチウム塩を除去するとともに、洗浄液の一部を炭酸リチウムとして残留させることで、従来と同等の初期容量を維持しつつ、正極合材ペースト混練時のゲル化を抑制し、さらに耐候性に優れた正極活物質が得られるとの知見を得て、本発明を完成したものである。 In order to solve the above problems, the present inventors have conducted extensive research on lithium metal composite oxides used as positive electrode active materials for non-aqueous electrolyte secondary batteries and methods for producing them. As a result, lithium nickel composite oxides have been studied. By washing the powder consisting of lithium carbonate with an aqueous solution of lithium carbonate, excess lithium salt is removed, and by leaving a part of the washing liquid as lithium carbonate, the initial capacity equivalent to that of the conventional one is maintained, and the positive electrode mixture is used. The present invention has been completed based on the finding that a positive electrode active material having excellent weather resistance can be obtained by suppressing gelation during paste kneading.
本発明の第１の態様では、一般式ＬｉｚＮｉ１－ｘ－ｙＣｏｘＭｙＯ２（ただし、０≦ｘ≦０．３５、０≦ｙ≦０．１０、０．９５≦ｚ≦１．１０、Ｍは、Ｍｎ、Ｖ、Ｍｇ、Ｍｏ、Ｎｂ、ＴｉおよびＡｌから選ばれる少なくとも１種の元素）で表されるリチウムニッケル複合酸化物からなる非水系電解質二次電池用正極活物質であって、炭酸リチウム含有量が０．５５質量％以上１．０質量％以下、水酸化リチウム含有量が０．２質量％以下および硫酸根含有量が０．０５質量％以下である非水系電解質二次電池用正極活物質が提供される。 In the first aspect of the present invention, the general formula Li z Ni 1-x-y Co x My O 2 (where 0 ≦ x ≦ 0.35, 0 ≦ y ≦ 0.10, 0.95 ≦ z ≦ z ≦ 1.10, M is a positive electrode active material for a non-aqueous electrolyte secondary battery made of a lithium nickel composite oxide represented by (at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al). A non-aqueous system having a lithium carbonate content of 0.55% by mass or more and 1.0% by mass or less, a lithium hydroxide content of 0.2% by mass or less, and a sulfuric acid root content of 0.05% by mass or less. A positive electrode active material for an electrolyte secondary battery is provided.
本発明の第２の態様では、上記非水系電解質二次電池用正極活物質を正極に含む非水系電解質二次電池が提供される。 In the second aspect of the present invention, there is provided a non-aqueous electrolyte secondary battery containing the positive electrode active material for the non-aqueous electrolyte secondary battery in the positive electrode.
本発明の正極活物質によれば、正極合材ペーストのゲル化を抑制し、かつ、耐候性に優れた非水系電解質二次電池用正極活物質を得ることができる。さらに、本発明の製造方法は、この正極活物質を容易に生産でき、特に工業的規模での大量生産に適するため、その工業的価値は極めて大きい。 According to the positive electrode active material of the present invention, it is possible to obtain a positive electrode active material for a non-aqueous electrolyte secondary battery that suppresses gelation of the positive electrode mixture paste and has excellent weather resistance. Further, the production method of the present invention can easily produce this positive electrode active material and is particularly suitable for mass production on an industrial scale, so that its industrial value is extremely large.
１．非水系電解質二次電池用正極活物質の製造方法
以下、図を参照して、本発明の実施形態の一例を説明する。図１は、本実施形態に係る非水系電解質二次電池用正極活物質の製造方法を示すフローチャートである。なお、以下の説明は、製造方法の一例であって、本発明の製造方法を限定するものではない。
1. 1. Method for Producing Positive Electrode Active Material for Non-Aqueous Electrolyte Secondary Battery An example of the embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to the present embodiment. The following description is an example of the manufacturing method, and does not limit the manufacturing method of the present invention.
図１に示すように、リチウムニッケル複合酸化物からなる粉末を炭酸リチウム水溶液により洗浄する（ステップＳ１）。まず、母材として、リチウムニッケル複合酸化物からなる粉末（以下、単に「粉末」ともいう。）を準備する。粉末は、一般式ＬｉｚＮｉ１－ｘ－ｙＣｏｘＭｙＯ２（ただし、０≦ｘ≦０．３５、０≦ｙ≦０．１０、０．９５≦ｚ≦１．１０、Ｍは、Ｍｎ、Ｖ、Ｍｇ、Ｍｏ、Ｎｂ、ＴｉおよびＡｌから選ばれる少なくとも１種の元素）で表されるリチウムニッケル複合酸化物からなる。 As shown in FIG. 1, the powder composed of the lithium nickel composite oxide is washed with an aqueous solution of lithium carbonate (step S1). First, as a base material, a powder made of a lithium nickel composite oxide (hereinafter, also simply referred to as “powder”) is prepared. The powder is of the general formula Li z Ni 1-xy Co x My O 2 (where 0 ≦ x ≦ 0.35, 0 ≦ y ≦ 0.10, 0.95 ≦ z ≦ 1.10, M is , Mn, V, Mg, Mo, Nb, Ti and Al).
粉末の製造方法は、特に限定されず、公知の方法で製造できる。粉末の製造方法は、例えば、リチウムを含む化合物と、リチウム以外の金属（ニッケル、コバルトなどの遷移金属やアルミニウム等）を含む化合物とを混合し、焼成する方法や、リチウムとリチウム以外の金属を含む水溶液を噴霧熱分解処理する方法や、中和晶析法により得られたリチウム以外の金属を含む水酸化物と、リチウム化合物とを混合し、焼成する方法などが挙げられる。これらの中でも、中和晶析法により得られたリチウム以外の金属を含む水酸化物、あるいは該水酸化物を熱処理して得られる酸化物を用いる方法は、得られる粉末の比表面積などを所望の範囲に容易に制御できる。また、粉末の原料として、硫酸塩、炭酸塩、水酸化物などを用い、粉末中にこれらに由来する物質が残留している場合、本実施形態の製造方法を好適に用いることができる。 The method for producing the powder is not particularly limited, and the powder can be produced by a known method. As a method for producing a powder, for example, a method of mixing a compound containing lithium and a compound containing a metal other than lithium (transition metal such as nickel and cobalt, aluminum, etc.) and firing, or a method of calcining a metal other than lithium and lithium is used. Examples thereof include a method of spray thermal decomposition treatment of the contained aqueous solution, a method of mixing a hydroxide containing a metal other than lithium obtained by a neutralization crystallization method, and a lithium compound, and firing. Among these, in the method using a hydroxide containing a metal other than lithium obtained by the neutralization crystallization method or an oxide obtained by heat-treating the hydroxide, the specific surface area of the obtained powder is desired. Can be easily controlled within the range of. Further, when a sulfate, a carbonate, a hydroxide or the like is used as a raw material for the powder and a substance derived from these remains in the powder, the production method of the present embodiment can be preferably used.
粉末の洗浄は、例えば、炭酸リチウム水溶液中に粉末を分散させて、攪拌し、スラリー化することにより行う。これにより、粉末を構成するリチウムニッケル複合酸化物の粒子表面に存在する、硫酸リチウムや水酸化リチウムなどを除去できる。また、これにより、同時に、水酸化リチウムを炭酸リチウムで置換できる。炭酸リチウム水溶液による洗浄により、従来の製造方法と同等又はそれ以上の初期容量を維持しつつ、正極合材ペーストのゲル化を抑制し、さらに耐候性に優れた正極活物質が得られる。 The powder is washed, for example, by dispersing the powder in an aqueous solution of lithium carbonate, stirring the powder, and forming a slurry. Thereby, lithium sulfate, lithium hydroxide and the like existing on the particle surface of the lithium nickel composite oxide constituting the powder can be removed. This also allows lithium hydroxide to be replaced with lithium carbonate at the same time. By cleaning with an aqueous solution of lithium carbonate, a positive electrode active material having an initial capacity equal to or higher than that of the conventional production method, suppressing gelation of the positive electrode mixture paste, and having excellent weather resistance can be obtained.
炭酸リチウム水溶液は、例えば、炭酸リチウムを水に溶解させて作製する。炭酸リチウム水溶液の濃度は、特に限定されず、水に可溶な範囲とすることができる。炭酸リチウム水溶液の濃度は、例えば、０．５ｇ／Ｌ以上１６．０ｇ／Ｌ以下である。濃度が、０．５ｇ／Ｌ未満である場合、水酸化リチウムの一部を炭酸リチウムとして残留させる効果が十分でなく、期待される効果が得られ難いことがある。一方、濃度が１６．０ｇ／Ｌを超える場合、炭酸リチウムの過飽和濃度に近いため、炭酸リチウム水溶液の調整が困難となることがある。また、炭酸リチウム水溶液の濃度の下限は、好ましくは、１．０ｇ／Ｌ以上であり、より好ましくは５．０ｇ／Ｌ以上、より好ましくは７．０ｇ／Ｌ以上である。濃度の下限が上記範囲である場合、より効果的に正極活物質中の炭酸リチウム含有量などを容易に所望の範囲に調整することができ、より高い耐候性を得ることができる。一方、炭酸リチウム水溶液の濃度の上限は、好ましくは、１５．０ｇ／Ｌ以下である。濃度の上限がこの範囲である場合、より高い耐候性を得ることができる。なお、炭酸リチウム水溶液中、一部の炭酸リチウムが二酸化炭素と反応し、炭酸水素リチウムを生成してもよい。 The lithium carbonate aqueous solution is prepared, for example, by dissolving lithium carbonate in water. The concentration of the lithium carbonate aqueous solution is not particularly limited and can be in the range soluble in water. The concentration of the lithium carbonate aqueous solution is, for example, 0.5 g / L or more and 16.0 g / L or less. When the concentration is less than 0.5 g / L, the effect of leaving a part of lithium hydroxide as lithium carbonate is not sufficient, and it may be difficult to obtain the expected effect. On the other hand, when the concentration exceeds 16.0 g / L, it may be difficult to adjust the lithium carbonate aqueous solution because it is close to the supersaturated concentration of lithium carbonate. The lower limit of the concentration of the lithium carbonate aqueous solution is preferably 1.0 g / L or more, more preferably 5.0 g / L or more, and more preferably 7.0 g / L or more. When the lower limit of the concentration is in the above range, the lithium carbonate content in the positive electrode active material can be easily adjusted to a desired range, and higher weather resistance can be obtained. On the other hand, the upper limit of the concentration of the lithium carbonate aqueous solution is preferably 15.0 g / L or less. When the upper limit of the concentration is in this range, higher weather resistance can be obtained. In the lithium carbonate aqueous solution, a part of lithium carbonate may react with carbon dioxide to generate lithium hydrogen carbonate.
粉末を含む炭酸リチウム水溶液のスラリー濃度は、特に限定されず、炭酸リチウム水溶液中に粉末が均一に分散されればよい。スラリー濃度は、例えば、１００ｇ／Ｌ以上３０００ｇ／Ｌ以下である。ここで、スラリー濃度の単位であるｇ／Ｌは、スラリー中の炭酸リチウム水溶液量（Ｌ）に対する粉末量（ｇ）を意味する。スラリー濃度が上記範囲である場合、スラリー濃度が高いほどスラリー中に含まれる粉末量は多くなり、大量の粉末を処理することができる。スラリー濃度の下限は、好ましくは２００ｇ／Ｌ以上、より好ましくは５００ｇ／Ｌ以上である。スラリー濃度の下限が上記範囲である場合、より効率的に水酸化リチウムの含有量を低減させ、炭酸リチウムの含有量を増加させることができる。一方、スラリー濃度の上限は、好ましくは２５００ｇ／Ｌ以下であり、より好ましくは２０００ｇ／Ｌ以下である。スラリー濃度の上限が上記範囲である場合、スラリーの粘度が適切な範囲となり、スラリーをより均一に攪拌することができ、硫酸リチウムや水酸化リチウムをより効率的に除去することができる。 The slurry concentration of the lithium carbonate aqueous solution containing the powder is not particularly limited, and the powder may be uniformly dispersed in the lithium carbonate aqueous solution. The slurry concentration is, for example, 100 g / L or more and 3000 g / L or less. Here, g / L, which is a unit of slurry concentration, means the amount of powder (g) with respect to the amount of lithium carbonate aqueous solution (L) in the slurry. When the slurry concentration is in the above range, the higher the slurry concentration, the larger the amount of powder contained in the slurry, and a large amount of powder can be processed. The lower limit of the slurry concentration is preferably 200 g / L or more, more preferably 500 g / L or more. When the lower limit of the slurry concentration is in the above range, the lithium hydroxide content can be reduced and the lithium carbonate content can be increased more efficiently. On the other hand, the upper limit of the slurry concentration is preferably 2500 g / L or less, and more preferably 2000 g / L or less. When the upper limit of the slurry concentration is in the above range, the viscosity of the slurry is in an appropriate range, the slurry can be agitated more uniformly, and lithium sulfate and lithium hydroxide can be removed more efficiently.
上記以外の洗浄の条件は、特に限定されず、粉末に残留した水酸化リチウムや硫酸根を十分除去し、炭酸リチウムの含有量が所望の範囲となるように、適宜調整することができる。例えば、粉末を含む炭酸リチウム水溶液を攪拌する場合、攪拌時間は、５分～１時間程度とすることができる。また、洗浄の温度は、例えば、１０℃～３０℃程度とすることができる。 The cleaning conditions other than the above are not particularly limited, and lithium hydroxide and sulfuric acid roots remaining in the powder can be sufficiently removed, and the content of lithium carbonate can be appropriately adjusted to be in a desired range. For example, when stirring an aqueous solution of lithium carbonate containing powder, the stirring time can be about 5 minutes to 1 hour. The cleaning temperature can be, for example, about 10 ° C to 30 ° C.
なお、洗浄の際、粉末中のリチウムがスラリー中に溶出し、洗浄前後で粉末のＬｉの原子比が異なるものとなることがある。この場合、洗浄によって変化する原子比は主にＬｉであり、洗浄前のＬｉ以外の金属の原子比は洗浄後も維持される。上記の洗浄により減少するＬｉの原子比は、例えば、０．０３～０．０８程度とする。炭酸リチウム水溶液を用いた洗浄は、通常の水を用いた洗浄と比較して、洗浄により減少するＬｉの原子比の値が小さく、Ｌｉの減少は緩和される傾向にある。洗浄後のＬｉの原子比は、予め洗浄条件を同じにした予備試験によって洗浄前後でのＬｉの原子比の減少量を確認し、母材としてＬｉの原子比を調整したリチウム金属複合酸化物粉末を用いることにより制御することができる。 During cleaning, lithium in the powder may elute into the slurry, and the atomic ratio of Li in the powder may differ before and after cleaning. In this case, the atomic ratio changed by washing is mainly Li, and the atomic ratio of the metal other than Li before washing is maintained even after washing. The atomic ratio of Li reduced by the above washing is, for example, about 0.03 to 0.08. Cleaning with an aqueous solution of lithium carbonate has a smaller value of the atomic ratio of Li reduced by washing as compared with washing with ordinary water, and the decrease in Li tends to be alleviated. As for the atomic ratio of Li after cleaning, the amount of decrease in the atomic ratio of Li before and after cleaning was confirmed by a preliminary test with the same cleaning conditions in advance, and the atomic ratio of Li was adjusted as the base material. Lithium metal composite oxide powder Can be controlled by using.
次に、図１に示すように、炭酸リチウム水溶液により洗浄した後、粉末を含むスラリーを濾過する（ステップＳ２）。濾過の方法は、特に限定されず、例えば、吸引濾過機、フィルタープレスや遠心機などの通常用いられる濾過装置を用いて、濾過を行うことができる。濾過を行うことにより、スラリーの固液分離の際、粉末表面に残存する付着水の量を減少させることができる。付着水が多い場合、液中に溶解したリチウム塩が再析出し、乾燥後リチウムニッケル複合酸化物粒子の表面に存在するリチウム量が期待する範囲から外れることがある。なお、ステップＳ２を行うか否かは任意である。ステップ２Ｓを行なわない場合、例えば、スラリーを静置し、又は、遠心し、上澄みを除去することなどにより、付着水を除去してもよい。 Next, as shown in FIG. 1, after washing with an aqueous solution of lithium carbonate, the slurry containing the powder is filtered (step S2). The method of filtration is not particularly limited, and filtration can be performed using, for example, a commonly used filtration device such as a suction filter, a filter press or a centrifuge. By performing filtration, the amount of adhering water remaining on the powder surface can be reduced during the solid-liquid separation of the slurry. When there is a large amount of adhering water, the lithium salt dissolved in the liquid may reprecipitate, and the amount of lithium present on the surface of the lithium-nickel composite oxide particles after drying may be out of the expected range. It is optional whether or not step S2 is performed. When step 2S is not performed, the adhering water may be removed by, for example, allowing the slurry to stand still or centrifuging it to remove the supernatant.
次に、図１に示すように、濾過後、得られた粉末を乾燥する（ステップＳ３）。乾燥温度は、特に限定されず、粉末に含まれる水分が十分除去される温度であればよい。乾燥温度は、例えば、８０℃以上３５０℃以下であるのが好ましい。乾燥温度が８０℃未満の場合、洗浄後の粉末の乾燥が遅くなるため、粉末表面と粉末内部との間でリチウム濃度の勾配が生じ、得られる正極活物質の電池特性が低下することがある。一方、乾燥温度が３５０℃を超える場合、粉末表面付近の結晶構造が崩れ、得られる正極活物質の電池特性が低下することがある。これは、洗浄後の粉末の表面付近の結晶構造は、化学量論比にきわめて近いか、もしくは若干リチウムが脱離して充電状態に近い状態になっており、崩れやすくなっているためであると考えられる。 Next, as shown in FIG. 1, after filtration, the obtained powder is dried (step S3). The drying temperature is not particularly limited as long as it is a temperature at which the water contained in the powder is sufficiently removed. The drying temperature is preferably, for example, 80 ° C. or higher and 350 ° C. or lower. If the drying temperature is less than 80 ° C., the drying of the powder after cleaning is delayed, so that a gradient of lithium concentration is generated between the surface of the powder and the inside of the powder, and the battery characteristics of the obtained positive electrode active material may be deteriorated. .. On the other hand, when the drying temperature exceeds 350 ° C., the crystal structure near the powder surface may collapse and the battery characteristics of the obtained positive electrode active material may deteriorate. This is because the crystal structure near the surface of the powder after washing is very close to the stoichiometric ratio, or the lithium is slightly desorbed and is in a state close to the charged state, and it is easy to collapse. Conceivable.
乾燥時間は、特に限定されず、乾燥後の粉末の水分率が０．２重量％以下、より好ましくは０．１重量％以下、さらに好ましくは０．０５重量％以下となる時間で乾燥することが好ましい。乾燥時間は、例えば、１時間以上２４時間以下である。なお、粉末の水分率は、カールフィッシャー水分計により気化温度３００℃で測定することができる。 The drying time is not particularly limited, and the powder is dried in such a time that the moisture content of the powder after drying is 0.2% by weight or less, more preferably 0.1% by weight or less, still more preferably 0.05% by weight or less. Is preferable. The drying time is, for example, 1 hour or more and 24 hours or less. The water content of the powder can be measured at a vaporization temperature of 300 ° C. using a Karl Fischer titer.
乾燥雰囲気は、炭素および硫黄を含む化合物成分を含有しないガス雰囲気下、または真空雰囲気下で乾燥することが好ましい。粉末中の炭素および硫黄量は、洗浄（ステップＳ１）により容易に制御できる。乾燥（ステップＳ３）時に、さらに炭素および硫黄化合物成分を含有する雰囲気下、または真空雰囲気下で乾燥すると、粉末中の炭素量および硫黄量が変化し、期待する効果が得られないことがある。 The drying atmosphere is preferably a gas atmosphere containing no compound component containing carbon and sulfur, or a vacuum atmosphere. The amount of carbon and sulfur in the powder can be easily controlled by washing (step S1). During drying (step S3), if the product is further dried in an atmosphere containing carbon and sulfur compound components or in a vacuum atmosphere, the amount of carbon and sulfur in the powder may change, and the expected effect may not be obtained.
なお、粉末中の炭素量及び硫黄量が後述する範囲に制御できれば、粉末の洗浄（ステップＳ１）後、ステップＳ２を行わずに、直接、乾燥（ステップＳ３）を行ってもよい。また、乾燥（ステップＳ３）後、得られた粉末は、正極活物質として正極合材ペーストの材料に用いることができる。また、乾燥（ステップＳ３）後、得られた粉末は、粉砕後、正極活物質として正極合材ペーストの材料に用いてもよい。 If the amount of carbon and the amount of sulfur in the powder can be controlled within the range described later, the powder may be directly dried (step S3) without performing step S2 after washing the powder (step S1). Further, after drying (step S3), the obtained powder can be used as a material for the positive electrode mixture paste as a positive electrode active material. Further, after drying (step S3), the obtained powder may be used as a positive electrode mixture paste material as a positive electrode active material after pulverization.
２．非水系電解質二次電池用正極活物質
本実施形態の非水系電解質二次電池用正極活物質は、一般式ＬｉｚＮｉ１－ｘ－ｙＣｏｘＭｙＯ２（ただし、０≦ｘ≦０．３５、０≦ｙ≦０．１０、０．９５≦ｚ≦１．１０、Ｍは、Ｍｎ、Ｖ、Ｍｇ、Ｍｏ、Ｎｂ、ＴｉおよびＡｌから選ばれる少なくとも１種の元素）で表されるリチウムニッケル複合酸化物からなり、炭酸リチウム含有量が０．４質量％以上１．５質量％以下、水酸化リチウム含有量が０．５質量％以下および硫酸根含有量が０．１質量％以下である。以下、正極活物質の実施形態の一例について説明する。
2. 2. Positive Active Material for Non-Aqueous Electrolyte Secondary Battery The positive electrode active material for non-aqueous electrolyte secondary battery of the present embodiment is the general formula Liz Ni 1-xy Co x My O 2 (however, 0 ≦ x ≦ 0). .35, 0 ≦ y ≦ 0.10, 0.95 ≦ z ≦ 1.10, M is represented by at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al). It is composed of lithium nickel composite oxide, and has a lithium carbonate content of 0.4% by mass or more and 1.5% by mass or less, a lithium hydroxide content of 0.5% by mass or less, and a sulfuric acid root content of 0.1% by mass or less. Is. Hereinafter, an example of the embodiment of the positive electrode active material will be described.
［組成］
上記一般式中、ｚは、リチウムニッケル複合酸化物中のＬｉ以外の金属元素（Ｎｉ、Ｃｏ及びＭ）を１としたときの、Ｌｉの元素比を示す。ｚの範囲は、０．９５≦ｚ≦１．１０である。ｚが０．９５未満である場合、正極の反応抵抗が大きくなり、電池出力が低くなることがある。一方、ｚが１．１０を超える場合、二次電池の安全性が低下することがある。電池出力及び安全性のバランスの観点から、ｚの範囲は、好ましくは０．９７≦ｚ≦１．０５、より好ましくは０．９７≦ｚ≦１．００である。ｚが上記範囲である場合、この正極活物質を含む二次電池は、電池出力及び安全性のバランスに優れる。上述したように、リチウムニッケル複合酸化物からなる粉末を母材として洗浄した場合、この粉末からＬｉが溶出することがある。したがって、洗浄する場合、洗浄前後でのＬｉの減少量を予備実験により確認し、洗浄後のＬｉの元素比が上記範囲となるように、洗浄前の粉末を準備することにより、Ｌｉの原子比を上記範囲とすることができる。
[composition]
In the above general formula, z indicates the element ratio of Li when the metal element (Ni, Co and M) other than Li in the lithium nickel composite oxide is 1. The range of z is 0.95 ≦ z ≦ 1.10. When z is less than 0.95, the reaction resistance of the positive electrode may increase and the battery output may decrease. On the other hand, if z exceeds 1.10, the safety of the secondary battery may decrease. From the viewpoint of the balance between battery output and safety, the range of z is preferably 0.97 ≦ z ≦ 1.05, more preferably 0.97 ≦ z ≦ 1.00. When z is in the above range, the secondary battery containing the positive electrode active material has an excellent balance between battery output and safety. As described above, when a powder made of a lithium nickel composite oxide is washed as a base material, Li may elute from this powder. Therefore, in the case of washing, the amount of decrease in Li before and after washing is confirmed by a preliminary experiment, and the atomic ratio of Li is prepared by preparing the powder before washing so that the elemental ratio of Li after washing is within the above range. Can be within the above range.
上記一般式中、ｘは、Ｌｉ以外の金属元素（Ｎｉ、Ｃｏ及びＭ）を１としたときの、Ｃｏの元素比を示す。ｘの範囲は、０≦ｘ≦０．３５であり、好ましくは０＜ｘ≦０．３５である。正極活物質にコバルトを含有させることで、良好なサイクル特性を得ることができる。これは、結晶格子のニッケルの一部をコバルトに置換することにより、充放電に伴うリチウムの脱挿入による結晶格子の膨張収縮挙動を低減できるためである。 In the above general formula, x indicates the element ratio of Co when the metal element (Ni, Co and M) other than Li is 1. The range of x is 0 ≦ x ≦ 0.35, preferably 0 <x ≦ 0.35. By containing cobalt in the positive electrode active material, good cycle characteristics can be obtained. This is because by substituting a part of nickel in the crystal lattice with cobalt, the expansion / contraction behavior of the crystal lattice due to the deinsertion / insertion of lithium due to charge / discharge can be reduced.
ｘの範囲は、二次電池のサイクル特性向上の観点から、好ましくは、０．０３≦ｘ≦０．３５であり、より好ましくは０．０５≦ｘ≦０．３である。また、ｘの範囲は、二次電池の電池容量の観点から、好ましくは、０．０３≦ｘ≦０．１５であり、より好ましくは０．０５≦ｘ≦０．１０である。一方、熱安定性を重視する場合、ｘの範囲は、好ましくは０．０７≦ｘ≦０．２５であり、より好ましくは０．１０≦ｘ≦０．２０である。 The range of x is preferably 0.03 ≦ x ≦ 0.35, and more preferably 0.05 ≦ x ≦ 0.3, from the viewpoint of improving the cycle characteristics of the secondary battery. Further, the range of x is preferably 0.03 ≦ x ≦ 0.15, and more preferably 0.05 ≦ x ≦ 0.10. From the viewpoint of the battery capacity of the secondary battery. On the other hand, when emphasis is placed on thermal stability, the range of x is preferably 0.07 ≦ x ≦ 0.25, more preferably 0.10 ≦ x ≦ 0.20.
上記一般式中、ｙは、Ｌｉ以外の金属元素（Ｎｉ、Ｃｏ及びＭ）を１としたときの、Ｍ（添加元素）の元素比を示す。Ｍは、Ｍｎ、Ｖ、Ｍｇ、Ｍｏ、Ｎｂ、ＴｉおよびＡｌから選ばれる少なくとも１種の元素である。ｙの範囲は、０≦ｙ≦０．１０であり、好ましくは、Ｍを必ず含む０＜ｙ≦０．１０ある。Ｍを正極活物質中に添加することにより、この正極活物質を含む二次電池の耐久特性や安全性を向上させることができる。一方、ｙが０．１０を超えると、酸化還元反応（Ｒｅｄｏｘ反応）に貢献する金属元素が減少し、電池容量が低下するため好ましくない。また、Ｍがアルミニウムである場合、正極活物質の安全性がより向上する。 In the above general formula, y indicates the element ratio of M (additional element) when the metal element (Ni, Co and M) other than Li is 1. M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al. The range of y is 0 ≦ y ≦ 0.10, preferably 0 <y ≦ 0.10. By adding M to the positive electrode active material, the durability characteristics and safety of the secondary battery containing the positive electrode active material can be improved. On the other hand, when y exceeds 0.10, the amount of metal elements contributing to the redox reaction (Redox reaction) decreases, and the battery capacity decreases, which is not preferable. Further, when M is aluminum, the safety of the positive electrode active material is further improved.
また、上記一般式中、ニッケルの元素比は、Ｌｉ以外の金属元素（Ｎｉ、Ｃｏ及びＭ）を１とした場合、０．５５以上１以下である。リチウムニッケル複合酸化物中の各金属元素の元素比は、Ｌｉ、Ｎｉ、Ｃｏ及びＭを含む原料の混合比を調整することにより上記範囲とすることができる。 Further, in the above general formula, the element ratio of nickel is 0.55 or more and 1 or less when the metal element (Ni, Co and M) other than Li is 1. The elemental ratio of each metal element in the lithium-nickel composite oxide can be set in the above range by adjusting the mixing ratio of the raw materials containing Li, Ni, Co and M.
［炭酸リチウム含有量］
本実施形態の正極活物質は、炭酸リチウム含有量が０．４質量％以上１．５質量％以下である。炭酸リチウム含有量が上記範囲である場合、リチウムニッケル複合酸化物表面の変質を防止し、耐候性の高い正極活物質が得られる。炭酸リチウム含有量が０．４質量％未満である場合、リチウムニッケル複合酸化物表面の変質防止する効果が薄れ、純分な耐候性を有する正極活物質が得られない。一方、炭酸リチウム含有量が１．５質量％を超える場合、正極活物質が高温環境下で充電されると、炭酸リチウムが分解しガス発生を引き起こすなど、電池特性が低下する。
[Lithium carbonate content]
The positive electrode active material of the present embodiment has a lithium carbonate content of 0.4% by mass or more and 1.5% by mass or less. When the lithium carbonate content is in the above range, deterioration of the surface of the lithium nickel composite oxide is prevented, and a positive electrode active material having high weather resistance can be obtained. When the lithium carbonate content is less than 0.4% by mass, the effect of preventing deterioration of the surface of the lithium nickel composite oxide is diminished, and a positive electrode active material having pure weather resistance cannot be obtained. On the other hand, when the lithium carbonate content exceeds 1.5% by mass, when the positive electrode active material is charged in a high temperature environment, the lithium carbonate is decomposed and gas is generated, and the battery characteristics are deteriorated.
ここで、正極活物質に含有される炭酸リチウムは、正極活物質に残留する水酸化リチウムが大気中の二酸化炭素により炭酸化して生じたもの、および、前述の洗浄に用いた炭酸リチウム水溶液に由来するものを含む。また、炭酸リチウム含有量の下限は、好ましくは０．４５質量％以上、より好ましくは０．５５質量％以上である。また、炭酸リチウム含有量の上限は、好ましくは１．０質量％以下である。炭酸リチウム含有量が上記範囲であることにより、耐候性により優れる正極活物質を得ることができる。なお、炭酸リチウムの含有量は、炭素硫黄分析装置（ＬＥＣＯ社製ＣＳ－６００）で正極活物質中の全炭素元素（Ｃ）含有量を測定し、この測定された炭素元素（Ｃ）量をＬｉＣＯ３に換算することにより求めた値である。また、炭酸リチウム（ＬｉＣＯ３）の存在は、Ｘ線回折測定の回折ピークの存在により確認することができる。 Here, the lithium carbonate contained in the positive electrode active material is derived from the lithium hydroxide remaining in the positive electrode active material carbonated by carbon dioxide in the atmosphere and the lithium carbonate aqueous solution used for the above-mentioned cleaning. Including what to do. The lower limit of the lithium carbonate content is preferably 0.45% by mass or more, more preferably 0.55% by mass or more. The upper limit of the lithium carbonate content is preferably 1.0% by mass or less. When the lithium carbonate content is in the above range, a positive electrode active material having better weather resistance can be obtained. As for the content of lithium carbonate, the total carbon element (C) content in the positive electrode active material was measured with a carbon sulfur analyzer (CS-600 manufactured by LECO), and the measured carbon element (C) amount was used. It is a value obtained by converting to LiCO 3 . Further, the presence of lithium carbonate (LiCO 3 ) can be confirmed by the presence of the diffraction peak in the X-ray diffraction measurement.
［硫酸根含有量］
本実施形態の正極活物質は、硫酸根（硫酸基）含有量が０．０５質量％以下、好ましくは０．０２５質量％以下、より好ましくは０．０２０質量％以下である。正極活物質中の硫酸基含有量が、０．０５質量％を超えると、電池を構成する際、正極活物質の不可逆容量に相当する分、負極材料を余計に電池に使用せざるを得ず、その結果、電池全体としての重量当たり及び体積当たりの容量が小さくなる上、不可逆容量として負極に蓄積された余分なリチウムは安全性の面からも問題となるため好ましくない。また、正極活物質中の硫酸根含有量の下限は、特に限定されないが、例えば、０．００１質量％以上である。
[Sulfuric acid root content]
The positive electrode active material of the present embodiment has a sulfuric acid root (sulfuric acid group) content of 0.05% by mass or less, preferably 0.025% by mass or less, and more preferably 0.020% by mass or less. If the sulfuric acid group content in the positive electrode active material exceeds 0.05% by mass, the negative electrode material must be used in the battery as much as the irreversible capacity of the positive electrode active material when constructing the battery. As a result, the capacity per weight and per volume of the battery as a whole becomes small, and the excess lithium accumulated in the negative electrode as an irreversible capacity poses a problem in terms of safety, which is not preferable. The lower limit of the sulfate root content in the positive electrode active material is not particularly limited, but is, for example, 0.001% by mass or more.
ここで、正極活物質に含有される硫酸根は、原料由来の不純物から生成した硫酸リチウムを主とする。なお、硫酸根含有量は、ＩＰＣ発光分光分析装置により、測定されたＳ（硫黄元素）量を、ＳＯ４量に換算して求めることができる。 Here, the sulfuric acid root contained in the positive electrode active material is mainly lithium sulfate produced from impurities derived from the raw material. The sulfuric acid root content can be obtained by converting the amount of S (sulfur element) measured by the IPC emission spectroscopic analyzer into the amount of SO4 .
［水酸化リチウム含有量］
本実施形態の正極活物質は、水酸化リチウム含有量が０．５質量％以下、好ましくは０．３質量％以下、より好ましくは０．２質量％以下である。正極活物質中の水酸化リチウム含有量が、０．５質量％を超えると、正極活物質をペーストに混練する際にゲル化を引き起こす原因になる。さらに正極活物質が高温環境下で充電される場合、水酸化リチウムが酸化分解しガス発生を引き起こす要因にもなる。なお、正極活物質中の水酸化リチウム含有量の下限は、特に限定されないが、例えば、０．０１質量％以上である。
[Lithium hydroxide content]
The positive electrode active material of the present embodiment has a lithium hydroxide content of 0.5% by mass or less, preferably 0.3% by mass or less, and more preferably 0.2% by mass or less. If the content of lithium hydroxide in the positive electrode active material exceeds 0.5% by mass, it causes gelation when the positive electrode active material is kneaded into the paste. Further, when the positive electrode active material is charged in a high temperature environment, lithium hydroxide becomes a factor of oxidative decomposition and gas generation. The lower limit of the lithium hydroxide content in the positive electrode active material is not particularly limited, but is, for example, 0.01% by mass or more.
ここで、正極活物質に含有される水酸化リチウムは、正極活物質を製造する際に用いた原料由来の水酸化リチウムを含み、例えば、ニッケル複合水酸化物又はニッケル複合酸化物などと水酸化リチウムなどのリチウム化合物を混合し、焼成する際の未反応物を含む。なお、水酸化リチウム含有量は、得られた正極活物質に純水を添加し攪拌した後、純水に溶出したリチウム（Ｌｉ）量を１ｍｏｌ／リットルの塩酸で中和滴定より測定し、その後、溶出したリチウム（Ｌｉ）量から前述の方法で得られたＬｉＣＯ３に由来するリチウム（Ｌｉ）量を差し引いた値を水酸化リチウム由来のリチウム（Ｌｉ）量とし、これをＬｉＯＨに換算することにより求めた値である。 Here, the lithium hydroxide contained in the positive electrode active material contains lithium hydroxide derived from the raw material used in producing the positive electrode active material, and is hydroxylated with, for example, a nickel composite hydroxide or a nickel composite oxide. Contains unreacted substances when a lithium compound such as lithium is mixed and fired. The lithium hydroxide content was determined by adding pure water to the obtained positive electrode active material and stirring, and then measuring the amount of lithium (Li) eluted in the pure water by neutralization titration with 1 mol / liter of hydrochloric acid. , The value obtained by subtracting the amount of lithium (Li) derived from LiCO 3 obtained by the above method from the amount of eluted lithium (Li) is taken as the amount of lithium (Li) derived from lithium hydroxide, and this is converted into LiOH. It is a value obtained by.
［平均粒径］
本実施形態の正極活物質の平均粒径は、特に限定されないが、例えば、３μｍ以上２５μｍ以下であることにより、正極活物質の容積あたりの電池容量を大きくすることができ、安全性が高く、サイクル特性が良好な二次電池を得ることができる。なお、平均粒径は、レーザ回折式粒度分布計により測定される値である。
[Average particle size]
The average particle size of the positive electrode active material of the present embodiment is not particularly limited, but for example, when it is 3 μm or more and 25 μm or less, the battery capacity per volume of the positive electrode active material can be increased, and the safety is high. A secondary battery having good cycle characteristics can be obtained. The average particle size is a value measured by a laser diffraction type particle size distribution meter.
［比表面積］
本実施形態の正極活物質の比表面積は、特に限定されないが、例えば、１．０ｍ２／ｇ以上７．０ｍ２／ｇ以下であり、電解液との接触できる粒子表面が十分にある。比表面積が１．０ｍ２／ｇ未満になると、電解液と接触できる粒子表面が少なくなり、十分な充放電容量が得られないことがある。一方、比表面積が７．０ｍ２／ｇを超えると、電解液と接触する粒子表面が多くなり過ぎて安全性が低下することがある。なお、比表面積は、窒素ガス吸着法によるＢＥＴ法を用いて比表面積測定装置により測定される値である。
[Specific surface area]
The specific surface area of the positive electrode active material of the present embodiment is not particularly limited, but is, for example, 1.0 m 2 / g or more and 7.0 m 2 / g or less, and there is a sufficient particle surface that can come into contact with the electrolytic solution. When the specific surface area is less than 1.0 m 2 / g, the particle surface that can come into contact with the electrolytic solution is reduced, and a sufficient charge / discharge capacity may not be obtained. On the other hand, if the specific surface area exceeds 7.0 m 2 / g, the number of particle surfaces that come into contact with the electrolytic solution becomes too large, which may reduce safety. The specific surface area is a value measured by a specific surface area measuring device using the BET method based on the nitrogen gas adsorption method.
本実施形態の正極活物質は、上述した正極活物質の製造方法を用いることにより、容易に、かつ、工業的規模で大量に生産することができる。 The positive electrode active material of the present embodiment can be easily mass-produced on an industrial scale by using the above-mentioned method for producing a positive electrode active material.
３．非水系電解質二次電池
本実施形態に係る非水系電解質二次電池は、上記正極活物質を正極に含む。本実施形態の非水系電解質二次電池は、一般の非水系電解質二次電池と同様に、正極、負極、セパレータ、および非水電解液から構成することができる。以下、非水系電解質二次電池の実施形態について、各構成要素、および電池の形状と構成について詳しく説明する。
3. 3. Non-aqueous electrolyte secondary battery The non-aqueous electrolyte secondary battery according to the present embodiment contains the above-mentioned positive electrode active material in the positive electrode. The non-aqueous electrolyte secondary battery of the present embodiment can be composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte solution, similarly to a general non-aqueous electrolyte secondary battery. Hereinafter, embodiments of the non-aqueous electrolyte secondary battery will be described in detail with respect to each component and the shape and configuration of the battery.
［正極］
正極を形成する正極合材及びそれを構成する各材料について説明する。本発明の粉末状の正極活物質と、導電材、結着剤とを混合し、さらに必要に応じて活性炭、粘度調整などの目的の溶剤を添加し、これを混練して正極合材ペーストを作製する。正極合材中のそれぞれの材料の混合比も、リチウム二次電池の性能を決定する重要な要素となる。
[Positive electrode]
The positive electrode mixture forming the positive electrode and each material constituting the positive electrode will be described. The powdery positive electrode active material of the present invention is mixed with a conductive material and a binder, and if necessary, activated carbon and a solvent for viscosity adjustment are added, and the mixture is kneaded to form a positive electrode mixture paste. To make. The mixing ratio of each material in the positive electrode mixture is also an important factor in determining the performance of the lithium secondary battery.
正極合材中の各材料の混合比は、特に限定されないが、一般のリチウム二次電池の正極と同様、溶剤を除いた正極合材の固形分の全質量１００質量％に対して、それぞれ、正極活物質を６０質量％以上９５質量％以下、導電材を１質量％以上２０質量％以下、結着剤（バインダー）を１質量％以上２０質量％以下含有することが望ましい。 The mixing ratio of each material in the positive electrode mixture is not particularly limited, but is the same as that of the positive electrode of a general lithium secondary battery, with respect to 100% by mass of the total solid content of the positive electrode mixture excluding the solvent. It is desirable that the positive electrode active material is contained in an amount of 60% by mass or more and 95% by mass or less, the conductive material is contained in an amount of 1% by mass or more and 20% by mass or less, and the binder is contained in an amount of 1% by mass or more and 20% by mass or less.
得られた正極合材ペーストは、例えば、アルミニウム箔製の集電体の表面に塗布し、乾燥して溶剤を飛散（蒸発）させる。必要に応じ、電極密度を高めるべくロールプレスなどにより加圧することもある。このようにしてシート状の正極を作製することができる。シート状の正極は、目的とする電池に応じて適当な大きさに裁断などし、電池の作製に供することができる。ただし、正極の作製方法は、上記例示のものに限られることなく、他の方法に依ってもよい。 The obtained positive electrode mixture paste is applied to the surface of a current collector made of aluminum foil, for example, and dried to disperse (evaporate) the solvent. If necessary, pressurization may be performed by a roll press or the like to increase the electrode density. In this way, a sheet-shaped positive electrode can be manufactured. The sheet-shaped positive electrode can be cut into an appropriate size according to the target battery and used for manufacturing the battery. However, the method for producing the positive electrode is not limited to the above-exemplified one, and other methods may be used.
上記正極の作製にあたって、導電材としては、例えば、黒鉛（天然黒鉛、人造黒鉛、膨張黒鉛など）やアセチレンブラック、ケッチェンブラックなどのカーボンブラック系材料などを用いることができる。 In producing the positive electrode, for example, graphite (natural graphite, artificial graphite, expanded graphite, etc.), carbon black materials such as acetylene black, and Ketjen black can be used as the conductive material.
また、結着剤は、活物質粒子をつなぎ止める役割を果たすもので、としては、例えば、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、エチレンプロピレンジエンゴム、フッ素ゴムなどの含フッ素樹脂、スチレンブタジエン、セルロース系樹脂、ポリアクリル酸、ポリプロピレン、ポリエチレンなどの熱可塑性樹脂などを用いることができる。 In addition, the binder plays a role of binding the active material particles, and includes, for example, polyvinylidene fluoride, polytetrafluoroethylene, ethylene propylenediene rubber, fluororesin such as fluororubber, styrene butadiene, and cellulose-based binder. Thermoplastic resins such as resins, polyacrylic acid, polypropylene, and polyethylene can be used.
また、必要に応じて、正極活物質、導電材、活性炭を分散させ、結着剤を溶解する溶剤を正極合材に添加してもよい。添加する溶剤としては、一例として、Ｎ－メチル－２－ピロリドンなどの有機溶剤を用いることができる。また、正極合材には電気二重層容量を増加させるために活性炭を添加してもよい。 Further, if necessary, a solvent that disperses the positive electrode active material, the conductive material, and the activated carbon and dissolves the binder may be added to the positive electrode mixture. As an example, an organic solvent such as N-methyl-2-pyrrolidone can be used as the solvent to be added. In addition, activated carbon may be added to the positive electrode mixture in order to increase the electric double layer capacity.
［負極］
負極には、金属リチウム、リチウム合金など、又は、リチウムイオンを吸蔵・脱離できる負極活物質に、結着剤を混合し、適当な溶剤を加えてペースト状にした負極合材を、銅などの金属箔集電体の表面に塗布、乾燥し、必要に応じて電極密度を高めるべく圧縮して形成したものを使用する。
[Negative electrode]
For the negative electrode, a negative electrode mixture such as metallic lithium, a lithium alloy, or a negative electrode active material capable of storing and desorbing lithium ions mixed with a binder and a suitable solvent is added to form a paste, such as copper. The metal foil of the above is applied to the surface of the current collector, dried, and compressed to increase the electrode density as necessary.
負極活物質としては、例えば、天然黒鉛、人造黒鉛、フェノール樹脂などの有機化合物焼成体、コークスなどの炭素物質の粉状体を用いることができる。この場合、負極結着剤としては、正極同様、ポリフッ化ビニリデンなどの含フッ素樹脂などを用いることができ、これら活物質及び結着剤を分散させる溶剤としてはＮ－メチル－２－ピロリドンなどの有機溶剤を用いることができる。 As the negative electrode active material, for example, a calcined body of an organic compound such as natural graphite, artificial graphite, or phenol resin, or a powdery body of a carbon substance such as coke can be used. In this case, as the negative electrode binder, a fluororesin such as polyvinylidene fluoride can be used as in the positive electrode, and as a solvent for dispersing these active substances and the binder, N-methyl-2-pyrrolidone or the like can be used. Organic solvents can be used.
［セパレータ］
正極と負極との間にはセパレータを挟み込んで配置する。セパレータは、正極と負極とを分離し電解質を保持するものであり、ポリエチレン、ポリプロピレンなどの薄い膜で、微少な穴を多数有する膜を用いることができる。
[Separator]
A separator is sandwiched between the positive electrode and the negative electrode. The separator separates the positive electrode and the negative electrode to retain the electrolyte, and a thin film such as polyethylene or polypropylene, which has a large number of minute holes, can be used.
［非水系電解液］
非水系電解液は、支持塩としてのリチウム塩を有機溶媒に溶解したものである。有機溶媒としては、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、トリフルオロプロピレンカーボネートなどの環状カーボネート、また、ジエチルカーボネート、ジメチルカーボネート、エチルメチルカーボネート、ジプロピルカーボネートなどの鎖状カーボネート、さらに、テトラヒドロフラン、２－メチルテトラヒドロフラン、ジメトキシエタンなどのエーテル化合物、エチルメチルスルホン、ブタンスルトンなどの硫黄化合物、リン酸トリエチル、リン酸トリオクチルなどのリン化合物などから選ばれる１種を単独で、あるいは２種以上を混合して用いることができる。
[Non-aqueous electrolyte solution]
The non-aqueous electrolyte solution is obtained by dissolving a lithium salt as a supporting salt in an organic solvent. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and trifluoropropylene carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate and dipropyl carbonate, and tetrahydrofuran and 2-. One selected from ether compounds such as methyl tetrahydrofuran and dimethoxyethane, sulfur compounds such as ethylmethyl sulfone and butane sulton, and phosphorus compounds such as triethyl phosphate and trioctyl phosphate is used alone or in combination of two or more. be able to.
支持塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＮ（ＣＦ３ＳＯ２）２など、及びそれらの複合塩を用いることができる。
さらに、非水系電解液は、ラジカル補足剤、界面活性剤及び難燃剤などを含んでいてもよい。
As the supporting salt, LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , LiN (CF 3 SO 2 ) 2 , and the like, and a composite salt thereof can be used.
Further, the non-aqueous electrolyte solution may contain a radical catching agent, a surfactant, a flame retardant and the like.
［電池の形状および構成］
本実施形態に係るリチウム二次電池の形状は、円筒型、積層型など、種々の形状とすることができる。いずれの形状を採る場合であっても、セパレータを介して正極及び負極を積層させ、電極体とし、この電極体に上記非水電解液を含浸させる。正極集電体と外部に通ずる正極端子との間、並びに負極集電体と外部に通ずる負極端子との間に集電用リードなどを用いて接続する。以上の構成のものを電池ケースに密閉して電池を完成させることができる。
[Battery shape and configuration]
The shape of the lithium secondary battery according to the present embodiment can be various shapes such as a cylindrical type and a laminated type. Regardless of which shape is adopted, the positive electrode and the negative electrode are laminated via a separator to form an electrode body, and the electrode body is impregnated with the non-aqueous electrolytic solution. A current collector lead or the like is used to connect between the positive electrode current collector and the positive electrode terminal leading to the outside, and between the negative electrode current collector and the negative electrode terminal leading to the outside. The battery can be completed by sealing the above configuration in a battery case.
以下、本発明の実施例及び比較例によって本発明をさらに詳細に説明するが、本発明はこれらの実施例によってなんら限定されるものではない。なお、実施例及び比較例は、以下の装置及び方法を用いた測定結果により評価した。 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples. The examples and comparative examples were evaluated based on the measurement results using the following devices and methods.
［組成、硫酸根含有量］
母材として用いたリチウムニッケル複合酸化物の粉末を硝酸で溶解した後、ＩＣＰ発光分光分析装置（株式会社島津製作所製、ＩＣＰＳ－８１００）により、各成分の組成比を測定した。また、硫酸根の測定は、ＩＣＰ発光分析により硫黄元素（Ｓ）含有量を測定し、この測定された硫黄元素の含有量をＳＯ４に換算することにより求めた。
[Composition, sulfate root content]
After dissolving the lithium nickel composite oxide powder used as the base material with nitric acid, the composition ratio of each component was measured by an ICP emission spectrophotometer (ICPS-8100, manufactured by Shimadzu Corporation). The sulfuric acid root was measured by measuring the sulfur element (S) content by ICP emission analysis and converting the measured sulfur element content into SO 4 .
［炭酸リチウム含有量］
炭酸リチウム含有量は、炭素硫黄分析装置（ＬＥＣＯ社製ＣＳ－６００）で全炭素元素（Ｃ）含有量を測定し、この測定された全炭素元素の量をＬｉ２ＣＯ３に換算することにより求めた。
[Lithium carbonate content]
The lithium carbonate content is determined by measuring the total carbon element (C) content with a carbon sulfur analyzer (CS-600 manufactured by LECO) and converting the measured amount of total carbon element into Li 2 CO 3 . I asked.
［水酸化リチウム含有量］
得られた正極活物質粉末１０ｇに超純水を１００ｍｌ添加して５分間攪拌し、ろ過した後、ろ液を１ｍｏｌ／リットルの塩酸で滴定し第二中和点まで測定した。塩酸で中和されたアルカリ分を、水酸化リチウム（ＬｉＯＨ）および炭酸リチウム（Ｌｉ２ＣＯ３）に由来するリチウム量（Ｌｉ）とした。また、前記方法で求めた、炭酸リチウム含有量から炭酸リチウム（Ｌｉ２ＣＯ３）由来のリチウム（Ｌｉ）量を算出した。そして、水酸化リチウム（ＬｉＯＨ）および炭酸リチウム（Ｌｉ２ＣＯ３）に由来するＬｉ量から、炭酸リチウム（Ｌｉ２ＣＯ３）由来のＬｉ量を引いた量を、水酸化リチウム（ＬｉＯＨ）由来のＬｉ量とし、このＬｉ量をＬｉＯＨに換算することにより、水酸化リチウム含有量とした。
[Lithium hydroxide content]
100 ml of ultrapure water was added to 10 g of the obtained positive electrode active material powder, stirred for 5 minutes, filtered, and the filtrate was titrated with 1 mol / liter hydrochloric acid and measured up to the second neutralization point. The alkali content neutralized with hydrochloric acid was defined as the amount of lithium (Li) derived from lithium hydroxide (LiOH) and lithium carbonate (Li 2 CO 3 ). In addition, the amount of lithium (Li) derived from lithium carbonate (Li 2 CO 3 ) was calculated from the lithium carbonate content obtained by the above method. Then, the amount obtained by subtracting the amount of Li derived from lithium carbonate (Li 2 CO 3 ) from the amount of Li derived from lithium hydroxide (LiOH) and lithium carbonate (Li 2 CO 3 ) is derived from lithium hydroxide (LiOH). The Li amount was used, and the Li amount was converted into LiOH to obtain the lithium hydroxide content.
［ペーストのゲル化の判定］
得られた正極活物質２０ｇに対して、ＰＶＤＦ（呉羽化学工業製、型番ＫＦポリマー＃１１００）２．２ｇと、ＮＭＰ（関東化学製）９．６ｍｌと容器に入れ、ニーダ（日本精機製作所、製品名ノンバブリングニーダ、型番ＮＢＫ－１）で２０００ｒｐｍの回転速度で１０分間十分に混合しペーストを作製した。得られたペーストをガラス瓶に移し、密栓した後、温度２５℃、露点－４０℃のドライボックス中に保管し、２４時間放置後のペーストの流動性を観察した。２４時間放置後、ペーストの流動性に変化のないものを◎、ペーストの流動性はあるが、流動性が変化したものを○、ペーストがゲル化したものを×と評価した。
[Judgment of paste gelation]
For 20 g of the obtained positive electrode active material, put 2.2 g of PVDF (manufactured by Kureha Chemical Industry Co., Ltd., model number KF polymer # 1100) and 9.6 ml of NMP (manufactured by Kanto Chemical Co., Inc.) in a container, and put them in a container. A paste was prepared by sufficiently mixing with a non-bubbling kneader (model number NBK-1) at a rotation speed of 2000 rpm for 10 minutes. The obtained paste was transferred to a glass bottle, sealed, and then stored in a dry box at a temperature of 25 ° C. and a dew point of −40 ° C., and the fluidity of the paste after being left for 24 hours was observed. After being left for 24 hours, those having no change in the fluidity of the paste were evaluated as ⊚, those having the fluidity of the paste but having the fluidity changed were evaluated as ◯, and those in which the paste was gelled were evaluated as ×.
［電池特性の評価（耐候性試験）］
（１）評価用コイン電池の作製
得られた正極活物質７０質量％に、アセチレンブラック２０質量％及びＰＴＦＥ１０質量％を混合し、ここから１５０ｍｇを取り出してペレットを作製し、正極とした。負極としてリチウム金属を用い、電解液として、１ＭのＬｉＣｌＯ４を支持塩とするエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）の等量混合溶液（富山薬品工業製）を用い、露点が－８０℃に管理されたＡｒ雰囲気のグローブボックス中で、図１に示すような２０３２型の評価用コイン電池ＢＡを作製した。２０３２型の評価用コイン電池ＢＡは、負極にリチウム金属負極１と、電解液を含浸させたセパレータ２と、正極３と、ガスケット４と、負極缶５と、正極缶６と、集電体７とを備える。
（２）放電容量の測定
該コイン電池を２４時間程度放置し、開路電圧ＯＣＶ（ｏｐｅｎ ｃｉｒｃｕｉｔ ｖｏｌｔａｇｅ）が安定した後、正極に対する電流密度を０．５ｍＡ／ｃｍ２としてカットオフ電圧４．３Ｖまで充電して充電容量とし、１時間の休止後カットオフ電圧３．０Ｖまで放電したときの容量を初期放電容量として測定した。
[Evaluation of battery characteristics (weather resistance test)]
(1) Preparation of Evaluation Coin Battery 20% by mass of acetylene black and 10% by mass of PTFE were mixed with 70% by mass of the obtained positive electrode active material, and 150 mg was taken out from this to prepare pellets and used as a positive electrode. A lithium metal is used as the negative electrode, and an equal amount mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO 4 as a supporting salt (manufactured by Tomiyama Pure Chemical Industries, Ltd.) is used as the electrolytic solution, and the dew point is -80 ° C. A 2032 type evaluation coin battery BA as shown in FIG. 1 was produced in a glove box having an Ar atmosphere controlled by the above. The 2032 type evaluation coin battery BA includes a lithium metal negative electrode 1, a
(2) Measurement of discharge capacity The coin battery is left to stand for about 24 hours, and after the open circuit voltage OCV (open circuit voltage) stabilizes, the current density with respect to the positive electrode is set to 0.5 mA / cm 2 and the battery is charged to a cutoff voltage of 4.3 V. Then, the charge capacity was used, and the capacity when the battery was discharged to a cutoff voltage of 3.0 V after a one-hour rest was measured as the initial discharge capacity.
（３）放電容量維持率の測定
得られた正極活物質を温度８０℃、相対湿度８０％の高温高湿条件下に２４時間静置した後、前記と同様の方法で、２０３２型の評価用コイン電池を作製し、上記同様の方法で放電容量を測定した。耐候性試験前の正極活物質（対照群）の初期放電容量を１００とした相対値から放電容量維持率を算出し、評価した。
(3) Measurement of discharge capacity retention rate After allowing the obtained positive electrode active material to stand for 24 hours under high temperature and high humidity conditions of 80 ° C. and 80% relative humidity, the same method as described above is used for evaluation of the 2032 type. A coin battery was manufactured, and the discharge capacity was measured by the same method as described above. The discharge capacity retention rate was calculated and evaluated from a relative value with the initial discharge capacity of the positive electrode active material (control group) before the weather resistance test as 100.
（実施例１）
ニッケルを主成分とする酸化物粉末と水酸化リチウムを混合して焼成する公知技術でＬｉ１．０３Ｎｉ０．８８Ｃｏ０．０９Ａｌ０．０３Ｏ２で表されるリチウムニッケル複合酸化物の焼成粉末を得た。この粉末を母材として用いた。この粉末の平均粒径は１２．０μｍであり、比表面積は１．２ｍ２／ｇであった。なお、平均粒径はレーザ回折式粒度分布計（日機装株式会社製、マイクロトラック）用い、比表面積は比表面積測定装置（ユアサアイオニクス株式会社製、カンタソーブＱＳ－１０）を用いて、窒素ガス吸着によるＢＥＴ法を用いて評価した。
上記リチウムニッケル複合酸化物の粉末（母材）に、濃度が１０．０ｇ／Ｌの炭酸リチウム水溶液を加えて、スラリーを作製した。この際のスラリー濃度は７５０ｇ／Ｌとした。このスラリーを３０分間攪拌して洗浄した。その後、粉末を濾過して取り出した。取り出した粉末を、真空雰囲気下、温度２１０℃で１４時間保持しながら乾燥して、リチウムニッケル複合酸化物からなる正極活物質を得た。得られた正極活物質をＩＣＰ発光分光分析装置で測定したところ、Ｌｉの原子比ｚは、０．９９２であった。得られた正極活物質の製造条件及び評価結果を表１に示した。
(Example 1)
Lithium-nickel composite oxide represented by Li 1.03 Ni 0.88 Co 0.09 Al 0.03 O 2 by a known technique of mixing and firing an oxide powder containing nickel as a main component and lithium hydroxide. A calcined powder was obtained. This powder was used as a base material. The average particle size of this powder was 12.0 μm, and the specific surface area was 1.2 m 2 / g. The average particle size is measured by using a laser diffraction type particle size distribution meter (Microtrac, manufactured by Nikkiso Co., Ltd.), and the specific surface area is measured by using a specific surface area measuring device (Cantasorb QS-10, manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas. It was evaluated using the BET method according to the above.
A lithium carbonate aqueous solution having a concentration of 10.0 g / L was added to the lithium nickel composite oxide powder (base material) to prepare a slurry. The slurry concentration at this time was 750 g / L. The slurry was stirred and washed for 30 minutes. Then, the powder was filtered out. The removed powder was dried under a vacuum atmosphere at a temperature of 210 ° C. for 14 hours to obtain a positive electrode active material composed of a lithium nickel composite oxide. When the obtained positive electrode active material was measured by an ICP emission spectrophotometer, the atomic ratio z of Li was 0.992. Table 1 shows the production conditions and evaluation results of the obtained positive electrode active material.
（実施例２）
実施例２では、ニッケルを主成分とする酸化物粉末と水酸化リチウムとを混合して焼成する公知技術で得られた、Ｌｉ１．０４Ｎｉ０．７２Ｃｏ０．２５Ａｌ０．０３Ｏ２で表されるリチウムニッケル複合酸化物粉末を母材として用いた以外は、実施例１と同様にして正極活物質を得た。得られた正極活物質の製造条件及び評価結果を表１に示した。なお、このリチウム金属複合酸化物粉末の平均粒径は１２．１μｍであり、比表面積は１．１ｍ２／ｇであった。
(Example 2)
In Example 2, Li 1.04 Ni 0.72 Co 0.25 Al 0.03 O 2 obtained by a known technique of mixing and firing an oxide powder containing nickel as a main component and lithium hydroxide. A positive electrode active material was obtained in the same manner as in Example 1 except that the lithium nickel composite oxide powder represented by 1 was used as a base material. Table 1 shows the production conditions and evaluation results of the obtained positive electrode active material. The average particle size of this lithium metal composite oxide powder was 12.1 μm, and the specific surface area was 1.1 m 2 / g.
（実施例３）
実施例３では、ニッケルを主成分とする、酸化物粉末と水酸化リチウムを混合して焼成する公知技術で得られた、Ｌｉ１．０２Ｎｉ０．９２Ｃｏ０．０５Ａｌ０．０３Ｏ２で表されるリチウムニッケル複合酸化物粉末を母材とした以外は、実施例１と同様にして正極活物質を得た。得られた正極活物質の製造条件及び評価結果を表１に示した。なお、このリチウム金属複合酸化物粉末の平均粒径は１２．２μｍであり、比表面積は１．３ｍ２／ｇであった。
(Example 3)
In Example 3, Li 1.02 Ni 0.92 Co 0.05 Al 0.03 O 2 obtained by a known technique in which an oxide powder containing nickel as a main component and lithium hydroxide are mixed and fired. A positive electrode active material was obtained in the same manner as in Example 1 except that the lithium nickel composite oxide powder represented by 1 was used as a base material. Table 1 shows the production conditions and evaluation results of the obtained positive electrode active material. The average particle size of this lithium metal composite oxide powder was 12.2 μm, and the specific surface area was 1.3 m 2 / g.
（実施例４）
実施例４では、炭酸リチウム水溶液の濃度を０．７ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例５）
実施例５では、炭酸リチウム水溶液の濃度を１．５ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例６）
実施例６では、炭酸リチウム水溶液の濃度を５．０ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例７）
実施例７では、炭酸リチウム水溶液の濃度を１５．０ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例８）
実施例８では、炭酸リチウム水溶液の濃度を１６．０ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例９）
実施例９では、スラリーの濃度を１００ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例１０）
実施例１０では、スラリーの濃度を３７５ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例１１）
実施例１１では、スラリーの濃度を１５００ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（実施例１２）
実施例１２では、スラリーの濃度を３０００ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
(Example 4)
In Example 4, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the lithium carbonate aqueous solution was set to 0.7 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 5)
In Example 5, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the lithium carbonate aqueous solution was set to 1.5 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 6)
In Example 6, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the lithium carbonate aqueous solution was adjusted to 5.0 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 7)
In Example 7, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the lithium carbonate aqueous solution was set to 15.0 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 8)
In Example 8, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the lithium carbonate aqueous solution was set to 16.0 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 9)
In Example 9, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the slurry was set to 100 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 10)
In Example 10, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the slurry was set to 375 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 11)
In Example 11, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the slurry was set to 1500 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Example 12)
In Example 12, a positive electrode active material was obtained in the same manner as in Example 1 except that the concentration of the slurry was set to 3000 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
（比較例１）
比較例１では、炭酸リチウム水溶液で洗浄する工程を行わなかったこと以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（比較例２）
比較例２では、炭酸リチウム水溶液の代わりに純水を用いた以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
（比較例３）
比較例３では、炭酸リチウム水溶液の代わりに純水を用い、スラリーの濃度を１５００ｇ／Ｌとなるようにした以外は、実施例１と同様にして正極活物質を得た。正極活物質の製造条件及び評価結果を表１に示した。
(Comparative Example 1)
In Comparative Example 1, a positive electrode active material was obtained in the same manner as in Example 1 except that the step of washing with an aqueous solution of lithium carbonate was not performed. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Comparative Example 2)
In Comparative Example 2, a positive electrode active material was obtained in the same manner as in Example 1 except that pure water was used instead of the lithium carbonate aqueous solution. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
(Comparative Example 3)
In Comparative Example 3, a positive electrode active material was obtained in the same manner as in Example 1 except that pure water was used instead of the lithium carbonate aqueous solution and the concentration of the slurry was set to 1500 g / L. Table 1 shows the production conditions and evaluation results of the positive electrode active material.
表１から明らかなように、実施例により得られた正極活物質は、炭酸リチウム含有量が０．４質量％以上１．５質量％以下であり、水酸化リチウム含有量が０．２質量％以下であり、かつ硫酸根含有量が０．０５質量％以下である。そのため、ペースト混練時のゲル化が抑制され、また、耐候性試験による放電容量維持率が８５％を超え、耐候性に優れることが示された。 As is clear from Table 1, the positive electrode active material obtained in the examples has a lithium carbonate content of 0.4% by mass or more and 1.5% by mass or less, and a lithium hydroxide content of 0.2% by mass. The content is less than or equal to 0.05% by mass and the content of sulfate root is 0.05% by mass or less. Therefore, gelation during paste kneading was suppressed, and the discharge capacity retention rate by the weather resistance test exceeded 85%, indicating that the weather resistance was excellent.
一方、比較例１では、炭酸リチウム水溶液による洗浄を行わなかったため、得られた正極活物質は、水酸化リチウム含有量及び硫酸根含有量ともに高くなった。そのため、ペースト混練時にゲル化が観察され、実施例の正極活物質と比較して、電池性能に劣るといえる。 On the other hand, in Comparative Example 1, since the cleaning with the lithium carbonate aqueous solution was not performed, the obtained positive electrode active material had high lithium hydroxide content and sulfuric acid root content. Therefore, gelation is observed during paste kneading, and it can be said that the battery performance is inferior to that of the positive electrode active material of the example.
比較例２および比較例３では、炭酸リチウムの代わりに純水を用いて洗浄したため、得られた正極活物質中の炭酸リチウム含有量が０．４質量％よりも低くなった。そのため、実施例の正極活物質と比較して、耐候性試験による放電容量維持率が低かった。 In Comparative Example 2 and Comparative Example 3, since the washing was performed using pure water instead of lithium carbonate, the lithium carbonate content in the obtained positive electrode active material was lower than 0.4% by mass. Therefore, the discharge capacity retention rate in the weather resistance test was lower than that in the positive electrode active material of the example.
以上の結果より、本実施形態の正極活物質製造方法を用いて、得られた正極活物質は、電池の正極材料として用いられた場合に正極合材ペーストのゲル化を抑制でき、さらに耐候性に優れた二次電池が得られることが明らかである。また、本実施形態の正極活物質は、非水系電解質二次電池の正極活物質として有用であることがわかる。 From the above results, the positive electrode active material obtained by using the positive electrode active material manufacturing method of the present embodiment can suppress gelation of the positive electrode mixture paste when used as the positive electrode material of a battery, and further has weather resistance. It is clear that an excellent secondary battery can be obtained. Further, it can be seen that the positive electrode active material of the present embodiment is useful as the positive electrode active material of the non-aqueous electrolyte secondary battery.
本発明により得られる正極活物質を正極に含む非水系電解質二次電池は、常に高容量を要求される小型携帯電子機器（ノート型パーソナルコンピュータや携帯電話端末など）の電源に好適に用いられることができ、また、高出力が要求される電気自動車用電池にも好適に用いられることができる。
また、本発明の非水系電解質二次電池は、優れた安全性を有し、小型化、高出力化が可能であることから、搭載スペースに制約を受ける電気自動車用電源として好適に用いられることができる。なお、本発明に係る非水系電解質二次電池は、純粋に電気エネルギーで駆動する電気自動車用の電源のみならず、ガソリンエンジンやディーゼルエンジンなどの燃焼機関と併用するいわゆるハイブリッド車用の電源としても用いることができる。
The non-aqueous electrolyte secondary battery containing the positive electrode active material obtained by the present invention in the positive electrode is suitably used as a power source for small portable electronic devices (notebook personal computers, mobile phone terminals, etc.) that always require high capacity. It can also be suitably used for electric vehicle batteries that require high output.
Further, the non-aqueous electrolyte secondary battery of the present invention has excellent safety, can be miniaturized and has a high output, and is therefore suitably used as a power source for an electric vehicle whose mounting space is restricted. Can be done. The non-aqueous electrolyte secondary battery according to the present invention can be used not only as a power source for an electric vehicle driven by purely electric energy, but also as a power source for a so-called hybrid vehicle used in combination with a combustion engine such as a gasoline engine or a diesel engine. Can be used.
ＢＡ・・・評価用コイン型電池
１・・・リチウム金属負極
２・・・セパレータ（電解液含浸）
３・・・正極（評価用電極）
４・・・ガスケット
５・・・負極缶
６・・・正極缶
７・・・集電体
BA ・ ・ ・ Coin-type battery for evaluation 1 ・ ・ ・ Lithium metal
3 ... Positive electrode (evaluation electrode)
4 ...
Claims (2)
A non-aqueous electrolyte secondary battery comprising the positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 in the positive electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022071967A JP2022095988A (en) | 2020-04-28 | 2022-04-25 | Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020079815A JP7262418B2 (en) | 2020-04-28 | 2020-04-28 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
| JP2022071967A JP2022095988A (en) | 2020-04-28 | 2022-04-25 | Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020079815A Division JP7262418B2 (en) | 2020-04-28 | 2020-04-28 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2022095988A true JP2022095988A (en) | 2022-06-28 |
Family
ID=71778979
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020079815A Active JP7262418B2 (en) | 2020-04-28 | 2020-04-28 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
| JP2022071967A Pending JP2022095988A (en) | 2020-04-28 | 2022-04-25 | Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020079815A Active JP7262418B2 (en) | 2020-04-28 | 2020-04-28 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (2) | JP7262418B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7262418B2 (en) * | 2020-04-28 | 2023-04-21 | 住友金属鉱山株式会社 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
| WO2023119949A1 (en) * | 2021-12-24 | 2023-06-29 | 株式会社村田製作所 | Secondary battery |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05182667A (en) * | 1991-12-28 | 1993-07-23 | Sony Corp | Manufacture of positive electrode material |
| KR20100096750A (en) * | 2009-02-25 | 2010-09-02 | 주식회사 엘앤에프신소재 | Positive active material for lithium secondary battery and lithium secondary battery including the same |
| JP2011023120A (en) * | 2009-07-13 | 2011-02-03 | Nippon Chem Ind Co Ltd | Positive active material for lithium secondary battery, method of manufacturing the same, and lithium secondary battery |
| JP2011023121A (en) * | 2009-07-13 | 2011-02-03 | Nippon Chem Ind Co Ltd | Positive active material for lithium secondary battery, method of manufacturing the same, and lithium secondary battery |
| JP7262418B2 (en) * | 2020-04-28 | 2023-04-21 | 住友金属鉱山株式会社 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3595734B2 (en) * | 1999-02-15 | 2004-12-02 | 株式会社デンソー | Positive active material for non-aqueous electrolyte secondary battery, method for producing the positive active material, and secondary battery using the positive active material |
| JP2001167767A (en) * | 1999-12-07 | 2001-06-22 | Sony Corp | Non-aqueous electrolyte secondary battery |
| JP2002203540A (en) * | 2000-12-28 | 2002-07-19 | Sony Corp | Nonaqueous electrolyte secondary battery |
| JP2002298914A (en) * | 2001-03-30 | 2002-10-11 | Toshiba Corp | Nonaqueous electrolyte secondary battery |
| JP4868786B2 (en) * | 2004-09-24 | 2012-02-01 | 三洋電機株式会社 | Lithium secondary battery |
| JP5618116B2 (en) * | 2008-09-12 | 2014-11-05 | 住友金属鉱山株式会社 | Non-aqueous electrolyte secondary battery using lithium nickel composite oxide and lithium nickel composite oxide as positive electrode active material |
| JP6026403B2 (en) * | 2011-03-24 | 2016-11-16 | Ｊｘ金属株式会社 | Positive electrode active material for lithium ion battery, positive electrode for lithium ion battery, and lithium ion battery |
| TWI482346B (en) * | 2011-04-28 | 2015-04-21 | Showa Denko Kk | Method of manufacturing cathode material for lithium secondary battery |
| JP6578635B2 (en) * | 2013-11-22 | 2019-09-25 | 住友金属鉱山株式会社 | Method for producing positive electrode active material for non-aqueous electrolyte secondary battery, positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery using the same |
-
2020
- 2020-04-28 JP JP2020079815A patent/JP7262418B2/en active Active
-
2022
- 2022-04-25 JP JP2022071967A patent/JP2022095988A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05182667A (en) * | 1991-12-28 | 1993-07-23 | Sony Corp | Manufacture of positive electrode material |
| KR20100096750A (en) * | 2009-02-25 | 2010-09-02 | 주식회사 엘앤에프신소재 | Positive active material for lithium secondary battery and lithium secondary battery including the same |
| JP2011023120A (en) * | 2009-07-13 | 2011-02-03 | Nippon Chem Ind Co Ltd | Positive active material for lithium secondary battery, method of manufacturing the same, and lithium secondary battery |
| JP2011023121A (en) * | 2009-07-13 | 2011-02-03 | Nippon Chem Ind Co Ltd | Positive active material for lithium secondary battery, method of manufacturing the same, and lithium secondary battery |
| JP7262418B2 (en) * | 2020-04-28 | 2023-04-21 | 住友金属鉱山株式会社 | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7262418B2 (en) | 2023-04-21 |
| JP2020115484A (en) | 2020-07-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11108043B2 (en) | Method for producing positive electrode active material for nonaqueous electrolyte secondary battery | |
| US9774036B2 (en) | Method for producing positive electrode active material for nonaqueous electrolyte secondary batteries, positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery using same | |
| JP6201277B2 (en) | Cathode active material for non-aqueous electrolyte secondary battery and method for producing the same | |
| JP7215423B2 (en) | Positive electrode active material for non-aqueous electrolyte secondary battery and manufacturing method thereof, and non-aqueous electrolyte secondary battery and manufacturing method thereof | |
| KR20190042102A (en) | Positive electrode active material for nonaqueous electrolyte secondary battery, manufacturing method of same, and nonaqueous electrolyte secondary battery using same | |
| CN109565048B (en) | Positive electrode active material for nonaqueous electrolyte secondary battery, and method for producing positive electrode active material for nonaqueous electrolyte secondary battery | |
| KR102632822B1 (en) | Positive electrode active material for non-aqueous electrolyte secondary battery, manufacturing method thereof, and non-aqueous electrolyte secondary battery | |
| US11289688B2 (en) | Positive electrode active material for nonaqueous electrolyte secondary batteries, production method thereof, and nonaqueous electrolyte secondary battery | |
| JP7262419B2 (en) | Positive electrode active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery | |
| JP2022095988A (en) | Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery | |
| JPWO2018221664A1 (en) | Positive active material for non-aqueous electrolyte secondary battery and method for producing the same, positive electrode mixture paste for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery | |
| WO2016132963A1 (en) | Lithium-iron-manganese-based composite oxide and lithium-ion secondary battery using same | |
| JP2019040844A (en) | Positive electrode active material for nonaqueous electrolyte secondary battery and method for manufacturing the same | |
| JP5181455B2 (en) | Cathode active material for non-aqueous electrolyte secondary battery, method for producing the same, and non-aqueous electrolyte secondary battery using the same | |
| WO2020171093A1 (en) | Method for producing positive electrode active material for lithium ion secondary batteries | |
| JP7271891B2 (en) | Positive electrode active material for lithium ion secondary battery, method for producing positive electrode active material for lithium ion secondary battery | |
| JP7308586B2 (en) | Positive electrode active material for non-aqueous electrolyte secondary batteries | |
| JP6961955B2 (en) | Non-aqueous electrolyte Positive electrode active material for secondary batteries | |
| JPWO2020171089A1 (en) | Method for manufacturing positive electrode active material for lithium ion secondary battery, positive electrode active material for lithium ion secondary battery, lithium ion secondary battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20220523 |
|
| RD04 | Notification of resignation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7424 Effective date: 20221116 |
|
| RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20221128 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20230627 |
|
| A601 | Written request for extension of time |
Free format text: JAPANESE INTERMEDIATE CODE: A601 Effective date: 20230822 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20231226 |