JP2022093903A - Gel electrolyte for lithium secondary battery, lithium secondary battery, and method for manufacturing lithium secondary battery - Google Patents
Gel electrolyte for lithium secondary battery, lithium secondary battery, and method for manufacturing lithium secondary battery Download PDFInfo
- Publication number
- JP2022093903A JP2022093903A JP2020206630A JP2020206630A JP2022093903A JP 2022093903 A JP2022093903 A JP 2022093903A JP 2020206630 A JP2020206630 A JP 2020206630A JP 2020206630 A JP2020206630 A JP 2020206630A JP 2022093903 A JP2022093903 A JP 2022093903A
- Authority
- JP
- Japan
- Prior art keywords
- lithium
- secondary battery
- lithium secondary
- mass
- negative electrode
- 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.)
- Granted
Links
- 239000011245 gel electrolyte Substances 0.000 title claims abstract description 66
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 60
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims description 41
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 76
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 73
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 60
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 60
- 239000003063 flame retardant Substances 0.000 claims abstract description 57
- 229920000642 polymer Polymers 0.000 claims abstract description 57
- 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 claims abstract description 56
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 55
- 150000001875 compounds Chemical class 0.000 claims abstract description 50
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 17
- 239000001301 oxygen Substances 0.000 claims abstract description 17
- 230000009467 reduction Effects 0.000 claims abstract description 13
- 125000004430 oxygen atom Chemical group O* 0.000 claims abstract description 10
- 239000003125 aqueous solvent Substances 0.000 claims description 56
- -1 phosphoric acid ester compound Chemical class 0.000 claims description 19
- 238000009835 boiling Methods 0.000 claims description 15
- 238000010248 power generation Methods 0.000 claims description 11
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 239000007784 solid electrolyte Substances 0.000 abstract description 16
- 239000002904 solvent Substances 0.000 abstract description 8
- 230000003647 oxidation Effects 0.000 abstract description 6
- 238000007254 oxidation reaction Methods 0.000 abstract description 6
- 239000000243 solution Substances 0.000 abstract description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 54
- 229940021013 electrolyte solution Drugs 0.000 description 42
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 35
- 230000000052 comparative effect Effects 0.000 description 35
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 27
- 208000028659 discharge Diseases 0.000 description 26
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 16
- 239000007773 negative electrode material Substances 0.000 description 15
- WVLBCYQITXONBZ-UHFFFAOYSA-N trimethyl phosphate Chemical compound COP(=O)(OC)OC WVLBCYQITXONBZ-UHFFFAOYSA-N 0.000 description 13
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical group CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 10
- 239000012757 flame retardant agent Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 239000003792 electrolyte Substances 0.000 description 9
- 239000007788 liquid Substances 0.000 description 9
- 238000002156 mixing Methods 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 9
- 239000011230 binding agent Substances 0.000 description 7
- 239000004020 conductor Substances 0.000 description 7
- 239000011888 foil Substances 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000002033 PVDF binder Substances 0.000 description 6
- 239000002202 Polyethylene glycol Substances 0.000 description 6
- 239000012528 membrane Substances 0.000 description 6
- 239000004014 plasticizer Substances 0.000 description 6
- 229920001223 polyethylene glycol Polymers 0.000 description 6
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 4
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 4
- 229910013528 LiN(SO2 CF3)2 Inorganic materials 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 4
- 239000004743 Polypropylene Substances 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 229920000573 polyethylene Polymers 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 239000007774 positive electrode material Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 3
- 229910013870 LiPF 6 Inorganic materials 0.000 description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 3
- 239000003575 carbonaceous material Substances 0.000 description 3
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 3
- 239000011267 electrode slurry Substances 0.000 description 3
- 238000010030 laminating Methods 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000011255 nonaqueous electrolyte Substances 0.000 description 3
- 239000005518 polymer electrolyte Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 3
- 229910052723 transition metal Inorganic materials 0.000 description 3
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 2
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical group C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000010494 dissociation reaction Methods 0.000 description 2
- 230000005593 dissociations Effects 0.000 description 2
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000002223 garnet Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- AMXOYNBUYSYVKV-UHFFFAOYSA-M lithium bromide Chemical compound [Li+].[Br-] AMXOYNBUYSYVKV-UHFFFAOYSA-M 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical class [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- OJURWUUOVGOHJZ-UHFFFAOYSA-N methyl 2-[(2-acetyloxyphenyl)methyl-[2-[(2-acetyloxyphenyl)methyl-(2-methoxy-2-oxoethyl)amino]ethyl]amino]acetate Chemical compound C=1C=CC=C(OC(C)=O)C=1CN(CC(=O)OC)CCN(CC(=O)OC)CC1=CC=CC=C1OC(C)=O OJURWUUOVGOHJZ-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 2
- DRVMZMGCPWFDBI-UHFFFAOYSA-N 2,2,2-trifluoroethyl dihydrogen phosphate Chemical compound OP(O)(=O)OCC(F)(F)F DRVMZMGCPWFDBI-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- 229910010238 LiAlCl 4 Inorganic materials 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910013188 LiBOB Inorganic materials 0.000 description 1
- 229910013684 LiClO 4 Inorganic materials 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910012513 LiSbF 6 Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229910000978 Pb alloy Inorganic materials 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- BEKPOUATRPPTLV-UHFFFAOYSA-N [Li].BCl Chemical compound [Li].BCl BEKPOUATRPPTLV-UHFFFAOYSA-N 0.000 description 1
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 description 1
- QSNQXZYQEIKDPU-UHFFFAOYSA-N [Li].[Fe] Chemical compound [Li].[Fe] QSNQXZYQEIKDPU-UHFFFAOYSA-N 0.000 description 1
- KLARSDUHONHPRF-UHFFFAOYSA-N [Li].[Mn] Chemical compound [Li].[Mn] KLARSDUHONHPRF-UHFFFAOYSA-N 0.000 description 1
- ZVLDJSZFKQJMKD-UHFFFAOYSA-N [Li].[Si] Chemical compound [Li].[Si] ZVLDJSZFKQJMKD-UHFFFAOYSA-N 0.000 description 1
- PWBXDCPGSHVVPB-UHFFFAOYSA-K [O-]P([O-])(=O)OP(=O)([O-])O.[Fe+2].[Li+] Chemical compound [O-]P([O-])(=O)OP(=O)([O-])O.[Fe+2].[Li+] PWBXDCPGSHVVPB-UHFFFAOYSA-K 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 150000004651 carbonic acid esters Chemical class 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- QHSJIZLJUFMIFP-UHFFFAOYSA-N ethene;1,1,2,2-tetrafluoroethene Chemical group C=C.FC(F)=C(F)F QHSJIZLJUFMIFP-UHFFFAOYSA-N 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910001337 iron nitride Inorganic materials 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- JWZCKIBZGMIRSW-UHFFFAOYSA-N lead lithium Chemical compound [Li].[Pb] JWZCKIBZGMIRSW-UHFFFAOYSA-N 0.000 description 1
- 239000011244 liquid electrolyte Substances 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- HSZCZNFXUDYRKD-UHFFFAOYSA-M lithium iodide Inorganic materials [Li+].[I-] HSZCZNFXUDYRKD-UHFFFAOYSA-M 0.000 description 1
- CASZBAVUIZZLOB-UHFFFAOYSA-N lithium iron(2+) oxygen(2-) Chemical compound [O-2].[Fe+2].[Li+] CASZBAVUIZZLOB-UHFFFAOYSA-N 0.000 description 1
- UIDWHMKSOZZDAV-UHFFFAOYSA-N lithium tin Chemical compound [Li].[Sn] UIDWHMKSOZZDAV-UHFFFAOYSA-N 0.000 description 1
- 208000020960 lithium transport Diseases 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- VROAXDSNYPAOBJ-UHFFFAOYSA-N lithium;oxido(oxo)nickel Chemical compound [Li+].[O-][Ni]=O VROAXDSNYPAOBJ-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000005486 organic electrolyte Substances 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 150000003014 phosphoric acid esters Chemical class 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- BHZCMUVGYXEBMY-UHFFFAOYSA-N trilithium;azanide Chemical compound [Li+].[Li+].[Li+].[NH2-] BHZCMUVGYXEBMY-UHFFFAOYSA-N 0.000 description 1
- XZZNDPSIHUTMOC-UHFFFAOYSA-N triphenyl phosphate Chemical compound C=1C=CC=CC=1OP(OC=1C=CC=CC=1)(=O)OC1=CC=CC=C1 XZZNDPSIHUTMOC-UHFFFAOYSA-N 0.000 description 1
- ZMQDTYVODWKHNT-UHFFFAOYSA-N tris(2,2,2-trifluoroethyl) phosphate Chemical compound FC(F)(F)COP(=O)(OCC(F)(F)F)OCC(F)(F)F ZMQDTYVODWKHNT-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は、リチウム二次電池用ゲル電解質、リチウム二次電池およびリチウム二次電池の製造方法に関する。 The present invention relates to a gel electrolyte for a lithium secondary battery, a lithium secondary battery, and a method for manufacturing a lithium secondary battery.
近年、環境保護のため二酸化炭素排出量の低減が切に望まれている。自動車業界では、電気自動車(EV)やハイブリッド電気自動車(HEV)の導入による二酸化炭素排出量の低減に期待が高まり、これらの実用化の鍵を握るモ-タ駆動用二次電池の開発が鋭意行われている。二次電池は、高エネルギ-密度、高出力密度が達成できる積層型のリチウムイオン二次電池が注目されている。 In recent years, there has been an urgent need to reduce carbon dioxide emissions in order to protect the environment. In the automobile industry, expectations are rising for the reduction of carbon dioxide emissions through the introduction of electric vehicles (EVs) and hybrid electric vehicles (HEVs), and the development of secondary batteries for motor drive, which holds the key to their practical application, is enthusiastic. It is done. As the secondary battery, a laminated lithium ion secondary battery capable of achieving high energy density and high output density is attracting attention.
現在、小型電子・電気機器用に市販されているリチウム二次電池の多くは、可燃性の有機溶媒を電解液として使用されている。有機溶媒電解液は、液漏れおよびそれに伴う発火などの危険性を有する。このようなリチウム二次電池を電気自動車のような大型用途に用いることは、リスクの増大を招く虞がある。それ故、より安全な電解質材料が求められている。その解決策のひとつとして不燃で、熱安定の高い固体電解質が注目されている。固体電解質は、ポリマ-系、硫化物系、LiSICON型、ガ-ネット型等に分類されている。硫化物系、LiSICON型およびガ-ネット型固体電解質は、室温下でのリチウムイオンの伝導率が高い。しかしながら、硫化物系は大気中で不安定で、かつ有毒ガスを放ち易くなる。LiSICON型およびガ-ネット型の固体電解質は、電極との接触問題が挙げられる。 Currently, most of the lithium secondary batteries commercially available for small electronic and electrical equipment use a flammable organic solvent as an electrolytic solution. The organic solvent electrolytic solution has a risk of liquid leakage and associated ignition. The use of such a lithium secondary battery in a large-scale application such as an electric vehicle may increase the risk. Therefore, there is a need for safer electrolyte materials. As one of the solutions, a solid electrolyte that is nonflammable and has high thermal stability is attracting attention. The solid electrolyte is classified into a polymer type, a sulfide type, a LiSION type, a garnet type and the like. Sulfide-based, LiSICON-type and garnet-type solid electrolytes have high lithium ion conductivity at room temperature. However, the sulfide system is unstable in the atmosphere and easily emits toxic gas. LiSION type and Garnet type solid electrolytes have a contact problem with electrodes.
固体状態でイオンを高速かつ選択的に伝導できるポリマ-固体電解質の研究は、1973年のWrightらの報告に端を発している。特許文献1には、ポリエチレンオキシド(PEO-[CH2CH2O]n-)が固体状態でアルカリ金属塩と錯体を形成し、室温でイオン導電性を示すことが開示されている。このような特許文献1によって、ポリマ-固体電解質を用いた全固体ポリマ-電池の可能性がはじめて示唆され、それ以来、今日に至るまで多岐にわたるポリマ-電解質の研究が進められてきた。 The study of polymer-solid electrolytes, which can conduct ions at high speed and selectively in the solid state, originated in the report of Wright et al. In 1973. Patent Document 1 discloses that polyethylene oxide (PEO- [CH 2 CH 2 O] n- ) forms a complex with an alkali metal salt in a solid state and exhibits ionic conductivity at room temperature. Such Patent Document 1 suggests for the first time the possibility of an all-solid-state polymer battery using a polymer-solid electrolyte, and since then, research on a wide range of polymer electrolytes has been promoted to this day.
ところで、ポリマ-固体電解質に要求される性質として次のようなものが挙げられる。第一に、非水溶媒電解質溶液に匹敵する高いイオン伝導度と低い温度依存性を有することである。高いイオン伝導度を得るには、電荷キャリア度(イオン度)が高く、固体中のキャリアの移動速度が大きいことが必要である。キャリア濃度は、ポリマ-中への塩(例えばリチウム塩)の溶解度とイオン解離の容易さにより決まる。一方、イオンの移動はポリマ-複合体の非晶質部分の熱運動と連動して起こる。このため、高いイオン移動度を得るにはポリマ-の構造が熱運動し易いことが望ましい。これまでに研究されてきた溶媒を含まない完全固体のPEO系ポリマ-は、室温でイオン導電率が極めて低く(~10-8S・cm-1)、室温でほぼ作動できないという問題点がある。第二に、ポリマ-固体電解質膜の製造と取り扱いが極めて困難である。ポリマ-固体電解質膜は、粘性が高く、複数枚積層する発電要素を製造する場合、注液が殆ど困難である。また、ポリマ-固体電解質を前もって正極または負極の互いに対向する表面に塗工する方法も提案されている。しかしながら、現行のリチウムイオン二次電池の製造ラインの積層機を用いて積層する操作は、ポリマ-固体電解質が高い粘性を有するために困難である。さらに、ポリマ-固体電解質膜は多量のリチウム塩を含むため、吸水性が非常に高くため、ドライル-ムで取り扱わなければならない。これは、現在のリチウムイオンの製造ラインに大掛かりの変更が必要になる。 By the way, the following properties are required for the polymer-solid electrolyte. First, it has high ionic conductivity and low temperature dependence comparable to non-aqueous solvent electrolyte solutions. In order to obtain high ionic conductivity, it is necessary that the charge carrier degree (ionic degree) is high and the carrier moving speed in the solid is high. The carrier concentration is determined by the solubility of the salt (eg, lithium salt) in the polymer and the ease of ion dissociation. On the other hand, the movement of ions occurs in conjunction with the thermal motion of the amorphous part of the polymer complex. Therefore, in order to obtain high ion mobility, it is desirable that the polymer structure is easy to thermally move. Solvent-free, completely solid PEO-based polymers that have been studied so far have a problem that they have extremely low ionic conductivity at room temperature (~ 10-8 S · cm -1 ) and can hardly operate at room temperature. .. Second, the polymer-solid electrolyte membrane is extremely difficult to manufacture and handle. The polymer-solid electrolyte membrane has a high viscosity, and it is almost difficult to inject liquid when manufacturing a power generation element in which a plurality of sheets are laminated. In addition, a method of applying a polymer-solid electrolyte to the surfaces of the positive electrode or the negative electrode facing each other in advance has also been proposed. However, the operation of laminating using a laminating machine on the current lithium ion secondary battery production line is difficult because the polymer-solid electrolyte has high viscosity. In addition, the polymer-solid electrolyte membrane contains a large amount of lithium salts and therefore has very high water absorption, so it must be handled in a dry room. This will require major changes to the current lithium-ion production line.
一方、可燃性非水溶媒を可塑剤としてを電解質に添加してイオン導電性を高めたゲル型ポリマ-電解質が知られている。可塑剤を加えることにより、ポリマ-であるPEOの鎖間またはPEOとリチウムイオン間の相互作用を弱め、結晶化を抑制してPEOのセグメント運動を活発化させることができる。例えば、炭酸エチレン、炭酸プロピレン、炭酸ジエチル、炭酸ジメチルなど炭酸エステル類非水溶媒を可塑剤として使用した例がある。また、非特許文献1には誘電率の高い可塑剤がリチウム塩の解離を助長するために有効であり、高誘電率のプロピレンカ-ボネ-トなどの非水溶媒が可塑剤として用いられていることが開示されている。 On the other hand, a gel-type polymer-electrolyte in which a flammable non-aqueous solvent is added as a plasticizer to the electrolyte to enhance ionic conductivity is known. By adding a plasticizer, the interaction between the chains of the polymer PEO or between the PEO and the lithium ion can be weakened, crystallization can be suppressed, and the segment movement of the PEO can be activated. For example, there is an example in which a non-aqueous solvent for carbonic acid esters such as ethylene carbonate, propylene carbonate, diethyl carbonate, and dimethyl carbonate is used as a plasticizer. Further, in Non-Patent Document 1, a plasticizer having a high dielectric constant is effective for promoting the dissociation of the lithium salt, and a non-aqueous solvent such as a propylene carbonate having a high dielectric constant is used as the plasticizer. It is disclosed that there is.
ただし、過度の添加は電解質膜の強度低下をもたらすとともに、液漏れや発火のリスクの増大を招く虞がある。 However, excessive addition may reduce the strength of the electrolyte membrane and increase the risk of liquid leakage and ignition.
また、高分子膜を電解質溶液で膨潤させたゲルを用いることにより、イオン伝導率も改善した、いわゆるゲル電解質を用いた電池が近年、注目されている。例えば、特許文献2にはリチウムイオン電池に使用するゲル電解質の可塑剤として、炭酸プロピレンなどの炭酸エステル系非水溶媒にLiPF6のようなリチウム塩を溶解させた電解液を用いると、導電率の比較的高いゲル電解質を得ることができることが開示されている。
Further, in recent years, a battery using a so-called gel electrolyte, in which the ionic conductivity is improved by using a gel in which a polymer film is swollen with an electrolyte solution, has attracted attention. For example, in
しかしながら、ゲル電解質はゲル型ポリマ-電解質と同様に、電解液の使用量が多いため、電池の外部への液漏れによる電解液の着火の虞がある。このため、依然として安全性の点で改良が求められていた。 However, since the gel electrolyte uses a large amount of the electrolytic solution like the gel-type polymer electrolyte, there is a risk of ignition of the electrolytic solution due to liquid leakage to the outside of the battery. For this reason, improvements were still required in terms of safety.
非特許文献2には、従来の4倍以上の高濃度リチウムイオンを含む“濃い液体”で、既存の電解液にはない「高速反応」、「高い分解耐性」、「高いリチウム輸送率」等新機能を持つ高濃度電解液が開示されている。有機電解液は、一般的にイオン伝導度が最大となる1mol/L付近の濃度が選択されているが、高濃度化により全ての溶媒分子をリチウムイオンに配位(溶媒和)させ、未配位(フリ-)の溶媒分子をなくすことにより、電気化学安定性を劇的に変化させるという意図がある。
Non-Patent
しかしながら、非特許参考文献2は非常に高い粘度の高濃度電解液を用いるため、流動性が低下し、現在のリチウムイオン二次電池の製造ラインの注液方式の適用が困難になり、取り扱い難くなる。
However, since Non-Patent
本発明は、ポリマ-固体電解質と高濃度電解液のメリットを合わせ持つリチウム二次電池用ゲル電解質、それを含むリチウム二次電池およびリチウム二次電池の製造方法を提供することである。 The present invention provides a gel electrolyte for a lithium secondary battery, which has the advantages of a polymer solid electrolyte and a high-concentration electrolytic solution, and a method for manufacturing a lithium secondary battery and a lithium secondary battery containing the same.
本発明は、主鎖においてO原子を含む高分子化合物、リチウム塩、還元安定性を有する非水溶媒および酸化安定性を有する難燃剤を含むリチウム二次電池用ゲル電解質である。高分子化合物の繰り返し単位中の酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)は、1~5である。高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]は、質量%表示で20~40である。高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]は、質量%表示で10~30である。 The present invention is a gel electrolyte for a lithium secondary battery containing a polymer compound containing an O atom in the main chain, a lithium salt, a non-aqueous solvent having reduction stability, and a flame retardant having oxidative stability. The molar ratio (O / Li) of the molar concentration (O) of oxygen in the repeating unit of the polymer compound and the molar concentration (Li) of lithium ions in the lithium salt is 1 to 5. The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%. The ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%.
本発明によれば、ゲル電解質中に存在する遊離の非水溶媒分子が消失し、高分子化合物と還元安定性を有する非水溶媒はリチウムイオンに配位して特殊な錯体構造を有し、さらに酸化安定性を有する難燃剤を配合することによって、高い電気化学的安定性、液漏れがなく、燃えないリチウム二次電池用ゲル電解質を提供できる。 According to the present invention, free non-aqueous solvent molecules present in the gel electrolyte disappear, and the polymer compound and the non-aqueous solvent having reduction stability have a special complex structure coordinated with lithium ions. Further, by blending a flame retardant having oxidative stability, it is possible to provide a gel electrolyte for a lithium secondary battery that has high electrochemical stability, does not leak, and does not burn.
また、前記ゲル電解質を組み込むことにより、高容量、高性能、高安全特性を有するリチウム二次電池およびその製造方法を提供することができる。 Further, by incorporating the gel electrolyte, it is possible to provide a lithium secondary battery having high capacity, high performance and high safety characteristics, and a method for manufacturing the same.
以下、本発明の実施形態に係るリチウム二次電池用ゲル電解質、リチウム二次電池およびリチウム二次電池の製造方法を詳細に説明する。 Hereinafter, a method for manufacturing a gel electrolyte for a lithium secondary battery, a lithium secondary battery, and a lithium secondary battery according to an embodiment of the present invention will be described in detail.
<第1の実施形態>
第1の実施形態に係るリチウム二次電池用ゲル電解質は、主鎖においてO原子を含む高分子化合物、リチウム塩、還元安定性を有する非水溶媒および酸化安定性を有する難燃剤を含む。高分子化合物の繰り返し単位中の酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)は、1~5である。高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]は、質量%表示で20~40である。高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]は、質量%表示で10~30である。
<First Embodiment>
The gel electrolyte for a lithium secondary battery according to the first embodiment contains a polymer compound containing an O atom in the backbone, a lithium salt, a non-aqueous solvent having reduction stability, and a flame retardant having oxidation stability. The molar ratio (O / Li) of the molar concentration (O) of oxygen in the repeating unit of the polymer compound and the molar concentration (Li) of lithium ions in the lithium salt is 1 to 5. The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%. The ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%.
主鎖においてO原子を含む高分子化合物は、例えばエチレンオキシド構造を有する高分子化合物を挙げることができる。このような高分子化合物の具体的な例は、ポリエチレンオキサイド(PEO)、ポリエチレングリコ-ルジメチルエステル(PEGDME),ポリエチレングリコ-ル(PEG)、ポリエチレンカ-ボンネット(PEC)等を挙げることができる。高分子化合物の重量平均分子量は、1,000~5,000,000であることが好ましい。 Examples of the polymer compound containing an O atom in the main chain include a polymer compound having an ethylene oxide structure. Specific examples of such polymer compounds include polyethylene oxide (PEO), polyethylene glycol dimethyl ester (PEGDME), polyethylene glycol (PEG), polyethylene carbonnet (PEC) and the like. .. The weight average molecular weight of the polymer compound is preferably 1,000 to 5,000,000.
リチウム塩は、特に限定されないが、例えばLiClO4、LiBOB,LiBF2(C2O4),LiBF4、LiPF6、LiAlCl4、LiSbF6、LiSCN、LiCF3SO3、LiAsF6、LiB10Cl10、低級脂肪族カルボン酸リチウム、LiCl、LiBr、LiI、クロロボランリチウム、四フェニルホウ酸リチウム、イミド化合物[(例えばLi(FSO2)2N、LiN(CF3SO2)2、LiN(C2F5SO2)2)]などを用いることができる。これらは単独で用いてもよく、2種以上を組み合わせて用いてもよい。 The lithium salt is not particularly limited, but is, for example, LiClO 4 , LiBOB, LiBF 2 (C 2 O 4 ), LiBF 4 , LiPF 6 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCF 3 SO 3 , LiAsF 6 , LiB 10 Cl 10 . Lithium lower aliphatic carboxylate, LiCl, LiBr, LiI, lithium chloroboran, lithium tetraphenylborate, imide compound [(eg Li (FSO 2 ) 2 N, LiN (CF 3 SO 2 ) 2 , LiN (C 2 F) 5 SO 2 ) 2 )] and the like can be used. These may be used alone or in combination of two or more.
ゲル電解質中におけるリチウム塩の濃度は、当該リチウム塩の析出等が発生しない範囲において高い濃度で選択することができる。高分子化合物中のエ-テル結合に由来する酸素のモル濃度[O]とリチウム塩のリチウムイオンのモル濃度[Li]のモル比:[O]/[Li]は、1~5である。当該モル比を1未満にすると、リチウム塩が完全に溶けずに、一部析出する虞がある。一方、当該モル比が5を超えると、遊離の非水溶媒分子(リチウムイオンと配位しない)が増える虞がある。 The concentration of the lithium salt in the gel electrolyte can be selected as high as long as the precipitation of the lithium salt does not occur. The molar ratio of the molar concentration [O] of oxygen derived from the ether bond in the polymer compound to the molar concentration [Li] of the lithium ion of the lithium salt: [O] / [Li] is 1 to 5. If the molar ratio is less than 1, the lithium salt may not be completely dissolved and may partially precipitate. On the other hand, if the molar ratio exceeds 5, there is a risk that free non-aqueous solvent molecules (not coordinated with lithium ions) will increase.
実施形態のゲル電解質は、後述するリチウム二次電池のセパレ-タに含浸させるために、適切な流動性を有することが好ましい。このため、実施形態のゲル電解質は高分子化合物、リチウム塩に加えて、非水溶媒を含む。非水溶媒は、低粘度、低沸点を有することが好ましい。これは、最小限の非水溶媒の添加により一定の流動性を付与し、かつ後述するリチウム二次電池の製造方法の加熱工程により容易に揮発させることができるためである。非水溶媒の25℃での粘度は、1mPa・S以下であることが好ましく、0.5mPa・S以下であることがさらに好ましい。沸点は100℃以下であることが好ましい。また、高い還元安定性、特にリチウム金属に安定できる非水溶媒が好ましい。このような低粘度、低沸点、高還元安定性の非水溶媒は、例えば、テトラヒドロフラン(THF)、2-メチルテトラヒドロフラン(2-MeTHF)、1,2-ジメトキシエタン(DME)、ジオキソラン(DOL)等のエ-テル類が好ましい。これらに加えて、その他の非水溶媒を含む混合溶媒とすることも可能である。 The gel electrolyte of the embodiment preferably has appropriate fluidity in order to impregnate the separator of the lithium secondary battery described later. Therefore, the gel electrolyte of the embodiment contains a non-aqueous solvent in addition to the polymer compound and the lithium salt. The non-aqueous solvent preferably has a low viscosity and a low boiling point. This is because a certain amount of fluidity can be imparted by adding a minimum amount of non-aqueous solvent, and the lithium secondary battery can be easily volatilized by the heating step of the method for manufacturing a lithium secondary battery described later. The viscosity of the non-aqueous solvent at 25 ° C. is preferably 1 mPa · S or less, and more preferably 0.5 mPa · S or less. The boiling point is preferably 100 ° C. or lower. Further, a non-aqueous solvent having high reduction stability, particularly stable to lithium metal, is preferable. Examples of such a non-aqueous solvent having low viscosity, low boiling point and high reduction stability include tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), 1,2-dimethoxyethane (DME) and dioxolane (DOL). Ethels are preferable. In addition to these, it is also possible to use a mixed solvent containing other non-aqueous solvents.
高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]は、質量%表示で20~40である。比率を20質量%未満にすると、リチウム二次電池のセパレ-タを実施形態のゲル電解質を含浸させた場合、セパレ-タに隣接する例えば正極の活物質との界面抵抗が高くて、室温でのリチウムイオンの伝導率が低下する。比率が40質量%を超えると、リチウム二次電池の性能向上が飽和するばかりか、二次電池が破裂した場合に非水溶媒の漏れが生じる可能性が高くなる。 The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%. When the ratio is less than 20% by mass, when the separator of the lithium secondary battery is impregnated with the gel electrolyte of the embodiment, the interface resistance with the active material of the positive electrode adjacent to the separator is high, for example, at room temperature. The conductivity of lithium ions is reduced. If the ratio exceeds 40% by mass, not only the performance improvement of the lithium secondary battery is saturated, but also the possibility of leakage of the non-aqueous solvent when the secondary battery bursts increases.
前記の還元安定性を有する非水溶媒は、実際充放電時においてのカットオフ電圧により、酸化されやすい場合がある。例えば、エ-テル系の非水溶媒は4V(Li/Li+)以上になれば、酸化される虞がある。というわけで、本発明にそのため、第1の実施形態において酸化安定性を有する難燃剤を添加する。難燃剤の添加目的は、単純にゲル電解質を燃えにくくなるだけではなく、ゲル電解質の高電位下の酸化を抑制する狙いもある。難燃剤は、例えばリン酸エステル類、スルホン化合物より選択される少なくとも1種を含む。具体的な難燃剤は、トリメチルフォスフェ-ト(TMP),トリエチルフォスフェ-ト(TEP),2,2,2-トリフルオロエチルフォスフェ-ト(TFP),トリフェニルフォスフェ-ト(TPP)およびトリトリルフォスフェ-ト(TTP)、トリス(2,2,2-トリフルオロエチル)ホスファ-ト(TFEP)、スルホラン(SL)など挙げられる。 The non-aqueous solvent having reduction stability may be easily oxidized by the cutoff voltage at the time of actual charge / discharge. For example, the ether-based non-aqueous solvent may be oxidized if it becomes 4 V (Li / Li + ) or more. Therefore, a flame retardant having oxidative stability is added to the present invention in the first embodiment. The purpose of adding the flame retardant is not only to make the gel electrolyte hard to burn, but also to suppress the oxidation of the gel electrolyte under high potential. The flame retardant contains at least one selected from, for example, phosphoric acid esters and sulfone compounds. Specific flame retardants are trimethyl phosphate (TMP), triethyl phosphate (TEP), 2,2,2-trifluoroethyl phosphate (TFP), triphenyl phosphate (TPP). ) And tritryl phosphate (TTP), tris (2,2,2-trifluoroethyl) phosphate (TFEP), sulfolane (SL) and the like.
高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]は、質量%表示で10~30である。この比率を10質量%未満にすると、難燃剤による十分な消火性をゲル電解質に付与できず、リチウム二次電池のセパレ-タにゲル電解質を含浸させた場合、引火すると二次電池が燃える虞がある。前記比率が30質量%を超えると、添加される難燃剤の種類により電池性能への悪影響を及ぼす虞がある。 The ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%. If this ratio is less than 10% by mass, the gel electrolyte cannot be sufficiently extinguished by the flame-retardant agent, and if the separator of the lithium secondary battery is impregnated with the gel electrolyte, the secondary battery may burn when ignited. There is. If the ratio exceeds 30% by mass, the battery performance may be adversely affected depending on the type of flame retardant added.
前記非水溶媒と前記難燃剤の沸点は、非水溶媒の沸点をa1,前記難燃剤の沸点をa2とすると、(a2-a1)≧100℃の関係を満たすことが好ましい。すなわち、非水溶媒の沸点を難燃剤の沸点より100℃以上の低沸点であることが好ましい。 The boiling points of the non-aqueous solvent and the flame-retardant agent preferably satisfy the relationship of (a2-a1) ≧ 100 ° C., where the boiling point of the non-aqueous solvent is a1 and the boiling point of the flame-retardant agent is a2. That is, it is preferable that the boiling point of the non-aqueous solvent is 100 ° C. or higher lower than the boiling point of the flame retardant.
第1の実施形態によれば、高分子化合物の繰り返し単位中の酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)、および高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]を特定化することによって、高分子化合物がリチウムイオンに配位するのみならず、非水溶媒もリチウムイオンに配位した特殊な錯体構造を形成することができる。その結果、高い還元安定性、リチウムイオン導電性および良好な流動性を有し、さらに電解質膜を作る必要がなく、取り扱いが容易なリチウム二次電池用ゲル電解質を得ることができる。
また、酸化安定性を有する難燃剤の配合にあたり、高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]を特定化することによって、ゲル電解質本来の特性を損なうことなく、非水溶媒の保持性の高い液漏れ性に優れ、かつ高い酸化還元安定性、難揮発性と難燃性を有する安全なリチウム二次電池用ゲル電解質を得ることができる。
According to the first embodiment, the molar ratio (O / Li) of the molar concentration (O) of oxygen in the repeating unit of the polymer compound to the molar concentration (Li) of lithium ions in the lithium salt, and high. By specifying the ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the molecular compound and the lithium salt, the polymer compound not only coordinates with lithium ions, but also. Non-aqueous solvents can also form special complex structures coordinated to lithium ions. As a result, it is possible to obtain a gel electrolyte for a lithium secondary battery which has high reduction stability, lithium ion conductivity and good fluidity, does not require the formation of an electrolyte membrane, and is easy to handle.
Further, when blending the flame-retardant agent having oxidation stability, the gel is specified by specifying the ratio [D / (A + B)] of the flame-retardant agent mass (D) to the total mass (A + B) of the polymer compound and the lithium salt. Obtains a safe gel electrolyte for lithium secondary batteries with high retention of non-aqueous solvent, excellent liquid leakage property, high redox stability, refractory volatility and flame retardancy without impairing the original characteristics of the electrolyte. be able to.
次に、第2の実施形態を説明する。
<第2の実施形態>
第2の実施形態に係るリチウム二次電池は、正極と、負極と、正極および負極の間に介在されたセパレ-タとを備える。第1の実施形態で説明したリチウム二次電池用ゲル電解質は、正極、負極およびセパレ-タに含浸されている。
Next, a second embodiment will be described.
<Second embodiment>
The lithium secondary battery according to the second embodiment includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The gel electrolyte for a lithium secondary battery described in the first embodiment is impregnated into a positive electrode, a negative electrode and a separator.
第2の実施形態に係るリチウムイオン二次電池の形状は特に限定されないが、例えばコイン型、ボタン型、シ-ト型、積層型、円筒型、角形、扁平型等が挙げられる。 The shape of the lithium ion secondary battery according to the second embodiment is not particularly limited, and examples thereof include a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a square type, and a flat type.
以下、コイン型のリチウムイオン二次電池を例にして、第2の実施形態に係るリチウムイオン二次電池の構造を、図1を参照して説明する。
コイン型のリチウムイオン二次電池1は、正極2と、負極3と、それら正極2および負極3の間に配置されたセパレ-タ4とを備える。これら正極2、負極3およびセパレ-タ4は、下部側に位置する第1外部端子5と上部側に位置する第2外部端子6の間に収納されている。当該第1外部端子5および当該第2外部端子6の当接部位は、ガスケット7により絶縁されている。
Hereinafter, the structure of the lithium ion secondary battery according to the second embodiment will be described with reference to FIG. 1, using a coin-type lithium ion secondary battery as an example.
The coin-type lithium ion secondary battery 1 includes a
正極2は、第1外部端子5の内面に位置してそれと接続される正極集電体21と、当該正極集電体21のセパレ-タ4と対向する面に設けられた正極層22とから構成されている。負極3は、第2外部端子6の内面に位置してそれと接続される負極集電体31と、当該負極集電体31のセパレ-タ4と対向する面に設けられた、金属リチウムからなる負極層32とから構成されている。セパレ-タ4は、前記ゲル電解質が含浸されている。第2外部端子6は、その端部がその下端及び両側面をガスケット7で包んだ状態で第1外部端子5内に挿入され、下部側の第1外部端子5の開口端をガスケット7側に湾曲させて第2外部端子6を第1外部端子5にかしめ固定するとともに、第1外部端子5及び第2外部端子6の当接部位をガスケット7により絶縁している。
The
以下に発電要素である正極、負極およびセパレ-タを詳述する。
(1)正極
正極を構成する正極集電体は、例えば、アルミニウム箔又はアルミニウム合金箔を用いることができる。
The positive electrode, negative electrode and separator, which are power generation elements, will be described in detail below.
(1) Positive electrode As the positive electrode current collector constituting the positive electrode, for example, an aluminum foil or an aluminum alloy foil can be used.
正極を構成する正極層は、正極活物質、導電性材料および結着剤を含む。
正極活物質は、公知のリチウムイオン二次電池用正極活物質を用いることができ、例えば、コバルト酸リチウム(LiCoO2)、マンガン酸リチウム(LiMn2O4)、ニッケル酸リチウム(LiNiO2)等の1種類以上の遷移金属を含むリチウム含有遷移金属酸化物、遷移金属硫化物、金属酸化物、リン酸鉄リチウム(LiFePO4)やピロリン酸鉄リチウム(Li2FeP2O7)などの1種類以上の遷移金属を含むリチウム含有ポリアニオン系化合物、硫黄系化合物(Li2S)などが挙げられる。
The positive electrode layer constituting the positive electrode contains a positive electrode active material, a conductive material and a binder.
As the positive electrode active material, a known positive electrode active material for a lithium ion secondary battery can be used, for example, lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 O 4 ), lithium nickel oxide (LiNiO 2 ) and the like. Lithium-containing transition metal oxides containing one or more of the transition metals, transition metal sulfides, metal oxides, lithium iron oxide (LiFePO 4 ), lithium iron pyrophosphate (Li 2 FeP 2 O 7 ), and the like. Examples thereof include lithium-containing polyanionic compounds and sulfur-based compounds (Li 2S ) containing the above transition metals.
導電性材料は、例えば、炭素材料、金属繊維等の導電性繊維、銅、銀、ニッケル、アルミニウム等の金属粉末、ポリフェニレン誘導体等の有機導電性材料を使用することができる。炭素材料は、黒鉛、ソフトカ-ボン、ハ-ドカ-ボン、カ-ボンブラック、ケッチェンブラック、アセチレンブラック、グラファイト、活性炭、カ-ボンナノチュ-ブ、カ-ボンファイバ-等を使用することができる。また、芳香環を含む合成樹脂、石油ピッチ等を焼成して得られたメソポ-ラスカ-ボンを使用することもできる。 As the conductive material, for example, a carbon material, a conductive fiber such as a metal fiber, a metal powder such as copper, silver, nickel and aluminum, and an organic conductive material such as a polyphenylene derivative can be used. As the carbon material, graphite, soft carbon, hard carbon, carbon black, Ketjen black, acetylene black, graphite, activated carbon, carbon nanotube, carbon fiber, etc. can be used. .. Further, a mesoporous carbon obtained by firing a synthetic resin containing an aromatic ring, petroleum pitch, or the like can also be used.
結着剤は、例えば、ポリフッ化ビニリデン(PVDF)、ポリテトラフルオロエチレン(PTFE)、エチレンテトラフルオロエチレン(ETFE)等のフッ素系樹脂、或いは、ポリエチレン、ポリプロピレンなどを好ましく用いることができる。 As the binder, for example, a fluororesin such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or ethylene tetrafluoroethylene (ETFE), or polyethylene or polypropylene can be preferably used.
(2)負極
負極を構成する負極集電体は、例えば銅、ニッケル、アルミニウム、ステンレススチ-ル等を主体とする棒状体、板状体、箔状体、網状体等を使用することができる。
(2) Negative electrode As the negative electrode current collector constituting the negative electrode, for example, a rod-shaped body, a plate-shaped body, a foil-shaped body, a mesh-like body or the like mainly composed of copper, nickel, aluminum, stainless steel or the like can be used. ..
負極を構成する負極層は、負極活物質のみを含有するものであってもよく、負極活物質の他に導電性材料および結着剤を含んでもよい。例えば、負極活物質が箔状である場合は、負極活物質のみで負極を構成することができる。一方、負極活物質が粉末状である場合は、負極活物質、導電性材料および結着剤により負極層を構成することができる。粉末状の負極活物質を用いて負極を形成する方法としては、ドクタ-ブレ-ド法や圧着プレスによる成型方法等を用いることができる。 The negative electrode layer constituting the negative electrode may contain only the negative electrode active material, or may contain a conductive material and a binder in addition to the negative electrode active material. For example, when the negative electrode active material is in the form of a foil, the negative electrode can be formed only by the negative electrode active material. On the other hand, when the negative electrode active material is in the form of powder, the negative electrode layer can be formed of the negative electrode active material, the conductive material and the binder. As a method for forming the negative electrode using the powdered negative electrode active material, a doctor-blade method, a molding method by a crimping press, or the like can be used.
前記箔状の負極層は、例えばリチウム金属、又はリチウム元素を含む合金から形成できる。リチウム元素を有する合金としては、例えばリチウムアルミニウム合金、リチウムスズ合金、リチウム鉛合金、リチウムケイ素合金等を挙げることができる。 The foil-shaped negative electrode layer can be formed from, for example, a lithium metal or an alloy containing a lithium element. Examples of the alloy having a lithium element include a lithium aluminum alloy, a lithium tin alloy, a lithium lead alloy, and a lithium silicon alloy.
負極活物質が粉末状である場合は、公知のリチウムイオン二次電池用負極活物質を用いることができる。例えば、天然グラファイト(黒鉛)、高配向性グラファイト(Highly Oriented Pyrolytic Graphite;HOPG)、非晶質炭素等の炭素質材料が挙げられる。他の負極活物質の例は、リチウムの酸化物、硫化物、窒化物が挙げられる。具体的なリチウム酸化物は、例えばチタン酸リチウム(Li4Ti5O12等)等を挙げることができる。リチウム窒化物は、例えばリチウムコバルト窒化物、リチウム鉄窒化物、リチウムマンガン窒化物等を挙げることができる。これら負極活物質は、単独または2種以上の混合物として用いることができる。 When the negative electrode active material is in the form of powder, a known negative electrode active material for a lithium ion secondary battery can be used. For example, carbonaceous materials such as natural graphite (graphite), highly oriented pyrolytic graphite (HOPG), and amorphous carbon can be mentioned. Examples of other negative electrode active materials include lithium oxides, sulfides and nitrides. Specific examples of the lithium oxide include lithium titanate (Li 4 Ti 5 O 12 and the like) and the like. Examples of the lithium nitride include lithium cobalt nitride, lithium iron nitride, lithium manganese nitride and the like. These negative electrode active materials can be used alone or as a mixture of two or more kinds.
導電性材料および結着剤は、前述した正極と同様のものを用いることができる。 As the conductive material and the binder, the same ones as those of the above-mentioned positive electrode can be used.
(3)セパレ-タ
セパレ-タは、例えばポリエチレン(PE)、ポリプロピレン(PP)、ポリイミド(PI)、ポリエステル、セルロ-ス、ポリアミド等の樹脂からなる多孔質シ-トまたは不織布、或いはガラス繊維不織布等の多孔質絶縁材料等を用いることができる。
(3) Separator The separator is a porous sheet or non-woven fabric made of a resin such as polyethylene (PE), polypropylene (PP), polyimide (PI), polyester, cellulose, polyamide, or glass fiber. A porous insulating material such as a non-woven fabric can be used.
第2の実施形態において、第1の実施形態で説明したリチウム二次電池用ゲル電解質は、正極、負極およびセパレ-タに含浸する。なお、負極を構成する負極層が負極活物質、導電材および結着剤を含む場合、前記ゲル電解質は負極層に含浸されるが、負極が前述した箔状の負極活物質からなる場合、前記ゲル電解質は当該箔状の負極活物質の表面、つまり箔状の負極活物質とセパレ-タの界面に存在する。 In the second embodiment, the gel electrolyte for a lithium secondary battery described in the first embodiment is impregnated into the positive electrode, the negative electrode and the separator. When the negative electrode layer constituting the negative electrode contains a negative electrode active material, a conductive material and a binder, the gel electrolyte is impregnated in the negative electrode layer, but when the negative electrode is made of the foil-shaped negative electrode active material described above, the above. The gel electrolyte exists on the surface of the foil-shaped negative electrode active material, that is, at the interface between the foil-shaped negative electrode active material and the separator.
なお、本発明の電解液及び二次電池は、二次電池としての用途に好適ではあるが、一次電池として用いることを除外するものではない。 Although the electrolytic solution and the secondary battery of the present invention are suitable for use as a secondary battery, it does not exclude the use as a primary battery.
第2の実施形態によれば、高いリチウムイオン導電性および良好な流動性を有し、かつゲル電解質を正極、負極、正極と負極の間に配置されたセパレ-タに含浸させることによって、正極とセパレ-タの間及び負極とセパレ-タの間の界面部の抵抗を低減でき、かつ正極、負極およびセパレ-タのリチウムイオン伝導率を向上できるため、高エネルギ-性、高出力性を有するリチウム二次電池を実現できる。 According to the second embodiment, the positive electrode has high lithium ion conductivity and good fluidity, and the gel electrolyte is impregnated into the positive electrode, the negative electrode, and the separator arranged between the positive electrode and the negative electrode. High energy and high output can be achieved because the resistance at the interface between the and the separator and between the negative electrode and the separator can be reduced, and the lithium ion conductivity of the positive electrode, the negative electrode and the separator can be improved. It is possible to realize a lithium secondary battery that has.
また、正極、負極、正極と負極の間に配置されたセパレ-タに含浸したゲル電解質は、非水溶媒の保持性が高く、液漏れ性に優れ、かつ高い難揮発性と難燃性を有するため、燃焼し難い安全性の高いリチウム二次電池を実現できる。 In addition, the gel electrolyte impregnated in the positive electrode, the negative electrode, and the separator arranged between the positive electrode and the negative electrode has high non-aqueous solvent retention, excellent liquid leakage, and high volatility and flame retardancy. Therefore, it is possible to realize a highly safe lithium secondary battery that is hard to burn.
次に、第3の実施形態に係るリチウム二次電池の製造方法を詳述する。
<第3の実施形態>
最初に、主鎖においてO原子を含む高分子化合物、リチウム塩、非水溶媒および難燃剤を含み、前記非水溶媒が前記高分子化合物、前記リチウム塩、前記非水溶媒および前記難燃剤の合計量に対して70~80質量%含むゲル電解液を調製する。
Next, the method for manufacturing the lithium secondary battery according to the third embodiment will be described in detail.
<Third embodiment>
First, the main chain contains a polymer compound containing an O atom, a lithium salt, a non-aqueous solvent and a flame retardant, and the non-aqueous solvent is the sum of the polymer compound, the lithium salt, the non-aqueous solvent and the flame retardant. A gel electrolytic solution containing 70 to 80% by mass based on the amount is prepared.
ゲル電解液の非水溶媒の配合量を70~80質量%にすることにより、ゲル電解液が高い流動性を有するため、現行の非水電解液を用いるリチウム二次電池の製造設備に変更を加えることなく使用ことが可能になる。 Since the gel electrolyte has high fluidity by adjusting the blending amount of the non-aqueous solvent in the gel electrolyte to 70 to 80% by mass, the current manufacturing equipment for lithium secondary batteries using the non-aqueous electrolyte has been changed. It can be used without adding.
次いで、正極、負極、および正極と負極の間に配置されるセパレ-タを備えた発電要素を作製する。正極、負極およびセパレ-タは、第2の実施形態で説明した構造とを有する。 Next, a power generation element having a positive electrode, a negative electrode, and a separator arranged between the positive electrode and the negative electrode is manufactured. The positive electrode, the negative electrode and the separator have the structure described in the second embodiment.
次いで、発電要素にゲル電解液を注入する。通常、発電要素は円筒型、角形の金属缶または2つの浅い缶を互いにガスケットで絶縁固定した外装材に収納され、当該外装材内にゲル電解液を注入する。 Then, the gel electrolytic solution is injected into the power generation element. Usually, the power generation element is housed in an exterior material in which a cylindrical or square metal can or two shallow cans are insulated and fixed to each other with a gasket, and a gel electrolytic solution is injected into the exterior material.
ゲル電解液の注入後に放置する。この工程により、ゲル電解液は正極、負極およびセパレ-タに拡散する。 Leave after injecting the gel electrolyte. By this step, the gel electrolytic solution diffuses into the positive electrode, the negative electrode and the separator.
次いで、発電要素を加熱してゲル電解液中の非水溶媒の一部を揮散させる。この工程により、発電要素の正極、負極およびセパレ-タに第1の実施形態で説明したゲル電解質を含浸させる。この工程において、第1の実施形態で説明したようにゲル電解質中の非水溶媒と難燃剤の沸点は、非水溶媒の沸点をa1,前記難燃剤の沸点をa2とすると、(a2-a1)≧100℃の関係を満たすこと好ましい。すなわち、非水溶媒の沸点を難燃剤の沸点より100℃以上の低沸点であることが好ましい。このような関係を満たすことにより、前記加熱工程において、難燃剤が揮散することなく、非水溶媒を優先的に揮散させることが可能になる。 Next, the power generation element is heated to volatilize a part of the non-aqueous solvent in the gel electrolyte. By this step, the positive electrode, the negative electrode and the separator of the power generation element are impregnated with the gel electrolyte described in the first embodiment. In this step, as described in the first embodiment, the boiling points of the non-aqueous solvent and the flame-retardant agent in the gel electrolyte are (a2-a1), where the boiling point of the non-aqueous solvent is a1 and the boiling point of the flame-retardant agent is a2. ) ≧ 100 ° C. is preferable. That is, it is preferable that the boiling point of the non-aqueous solvent is 100 ° C. or higher lower than the boiling point of the flame retardant. By satisfying such a relationship, it becomes possible to preferentially volatilize the non-aqueous solvent in the heating step without volatilizing the flame retardant.
以上説明した第3の実施形態によれば、現行の非水電解液を用いるリチウム二次電池の製造設備に変更を加えることなく、当該設備を使用できるため、簡易な方法で安価に良好な電気化学性能および安全性の高いリチウム二次電を製造できる。 According to the third embodiment described above, since the equipment can be used without changing the existing equipment for manufacturing a lithium secondary battery using a non-aqueous electrolyte solution, good electricity can be used inexpensively by a simple method. It is possible to produce lithium secondary batteries with high chemical performance and safety.
以下、本発明を実施例を用いて詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to examples.
(実施例1)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)1gと、THF15gとを混合し、さらにのLiN(SO2CF3)21.29gを加えた。このとき、ポリエチレンオキシド中のエ-テル酸素のモル濃度[EO]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比率(Li/EO)を5とした。得られたPEOとTHFとリチウム塩との混合物に、15wt%のスルホラン(SL)を難燃剤として加えて、電解質溶液を調製した。
(Example 1)
(1) Preparation of electrolyte solution 1 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 15 g of THF were mixed, and further LiN (SO 2 CF 3 ) 2 1.29 g was added. .. At this time, the molar ratio (Li / EO) of the molar concentration [EO] of ether oxygen in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 5. An electrolyte solution was prepared by adding 15 wt% sulfolane (SL) as a flame retardant to the obtained mixture of PEO, THF and a lithium salt.
(2)正極の作製
84.4質量%のLiFePO40.5gと、5.0質量%のNASION型固体電解質(LICGCPW-01,オハラ製)0.03g、0.6質量%の多層カ-ボンナノチュ-ブ分散液0.13g(溶媒はCnano製のN-メチル-2-ピロリドン(NMP)である)、10質量%のポリフッ化ビニリデン(PVDF)0.5g、をそれぞれ添加して混合した後、当該混合物に溶剤としてNMPを更に適量添加して正極スラリ-を調製した。つづいて、正極集電体である厚さ20μmのアルミニウム箔上に正極スラリ-を塗布し、80℃で12時間乾燥した。その後、ロ-ルプレスを用いて5MPaでプレスし、さらに打抜き加工して直径14mmの円形の正極を作製した。
(2) Preparation of positive electrode 84.4% by mass LiFePO 4 0.5 g, 5.0% by mass NASION type solid electrolyte (LICGCPW-01, manufactured by O'Hara) 0.03 g, 0.6% by mass multi-layer solvent After adding 0.13 g of Bonnanotube dispersion (solvent is N-methyl-2-pyrrolidone (NMP) manufactured by Canon) and 0.5 g of 10% by mass of polyvinylidene fluoride (PVDF) and mixing. An appropriate amount of NMP was further added to the mixture as a solvent to prepare a positive slurry. Subsequently, a positive electrode slurry was applied onto an aluminum foil having a thickness of 20 μm, which is a positive electrode current collector, and dried at 80 ° C. for 12 hours. Then, it was pressed at 5 MPa using a roll press and further punched to prepare a circular positive electrode having a diameter of 14 mm.
(3)負極の作製
負極には、直径15mm、厚さ600μmの円板状リチウム金属箔を用いた。
(3) Preparation of Negative Electrode A discoid lithium metal foil having a diameter of 15 mm and a thickness of 600 μm was used for the negative electrode.
(4)正極層およびセパレ-タ層にゲル電解質を付与
露点-50℃以下の雰囲気下、正極およびセパレ-タの表面に予め調製した電解質溶液を付与した。すなわち、正極を外部端子に載せ、この上にセパレ-タを載せて、ピペットを使って600μLを直接表面に付与した。セパレ-タ層の厚さは10~25μmとした。その後ホットプレ-トに載せて決められたTHFの残量まで加熱した。電解質溶液は加熱前のサラサラ状態からネバネバ状態のゲル電解質に変わった。加熱温度と加熱時間はTHFの残留量によって決められる。本例の加熱温度は50℃、加熱時間は10分であった。負極はピペットを使って電解質溶液を直接表面に付与し、同様に加熱してゲル電解質を形成した。
(4) Applying gel electrolyte to the positive electrode layer and the separator layer An electrolyte solution prepared in advance was applied to the surfaces of the positive electrode and the separator under an atmosphere of a dew point of −50 ° C. or lower. That is, the positive electrode was placed on an external terminal, a separator was placed on the positive electrode, and 600 μL was directly applied to the surface using a pipette. The thickness of the separator layer was 10 to 25 μm. After that, it was placed on a hot plate and heated to the determined remaining amount of THF. The electrolyte solution changed from a smooth state before heating to a sticky gel electrolyte. The heating temperature and heating time are determined by the residual amount of THF. The heating temperature of this example was 50 ° C., and the heating time was 10 minutes. For the negative electrode, an electrolyte solution was directly applied to the surface using a pipette and heated in the same manner to form a gel electrolyte.
(5)電池の作製
セパレ-タを介して正極と対向するように負極と積層し、前述した図1に示すコイン型リチウムイオン二次電池(2032型)を組立てた。
(5) Preparation of Battery A coin-type lithium ion secondary battery (2032 type) shown in FIG. 1 described above was assembled by laminating it with a negative electrode so as to face the positive electrode via a separator.
(実施例2)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)1gと、テトラヒドロフラン(THF)15gとを混合し、さらにLiN(SO2CF3)26.45gを加えた。このとき、ポリエチレンオキシド中のエ-テル酸素のモル濃度[EO]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比率(Li/EO)1とした。得られたPEOとTHFとリチウム塩との混合物に、10wt%のTMPを難燃剤として加えて、電解質溶液を得た。
次いで、前記電解質溶液を用い、ホットプレ-トにより50℃で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 2)
(1) Preparation of electrolyte solution 1 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 15 g of tetrahydrofuran (THF) are mixed, and then LiN (SO 2 CF 3 ) 2 6.45 g. Was added. At this time, the molar ratio (Li / EO) of the molar concentration [EO] of ether oxygen in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 1. To the obtained mixture of PEO, THF and a lithium salt, 10 wt% TMP was added as a flame retardant to obtain an electrolyte solution.
Next, a coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate.
(実施例3)
実施例2と同様な方法により電解質溶液を調製し、同実施例2と同様に電解質溶液をホットプレ-トにより50℃で20分加熱し、さらに難燃剤として15wt%のTMPを用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 3)
The electrolyte solution was prepared by the same method as in Example 2, the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate in the same manner as in Example 2, and 15 wt% TMP was used as a flame retardant. A coin-type lithium ion secondary battery was assembled by the same method as in Example 1.
(実施例4)
実施例2と同様な方法により電解質溶液を作製し、同実施例2と同様に電解質溶液をホットプレ-トで20分加熱し、さらに難燃剤としてTMPの代わりに15wt%のスルホランを用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 4)
An electrolyte solution was prepared by the same method as in Example 2, the electrolyte solution was heated with a hot plate for 20 minutes in the same manner as in Example 2, and 15 wt% sulfolane was used as a flame retardant instead of TMP. A coin-type lithium ion secondary battery was assembled by the same method as in Example 1.
(実施例5)
実施例2と同様な方法により電解質溶液を作製し、同実施例2と同様に電解質溶液をホットプレ-トで20分加熱し、さらに難燃剤としてTMPの代わりに25wt%のスルホランを用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 5)
An electrolyte solution was prepared by the same method as in Example 2, the electrolyte solution was heated with a hot plate for 20 minutes in the same manner as in Example 2, and 25 wt% sulfolane was used as a flame retardant instead of TMP. A coin-type lithium ion secondary battery was assembled by the same method as in Example 1.
(実施例6)
実施例2と同様な方法により電解質溶液を作製し、同実施例2と同様に電解質溶液をホットプレ-トで20分加熱し、さらに難燃剤として10wt%の2,2,2-トリフルオロエチルフォスフェ-ト(TFP)を用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 6)
An electrolyte solution was prepared by the same method as in Example 2, the electrolyte solution was heated with a hot plate for 20 minutes in the same manner as in Example 2, and 10
(比較例1)
難燃剤を添加しない以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 1)
A coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that no flame retardant was added.
(比較例2)
難燃剤を添加せず、ホットプレ-トにより50℃で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 2)
A coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that it was heated at 50 ° C. for 20 minutes by a hot plate without adding a flame retardant.
(比較例3)
難燃剤として25wt%のスルホランを用い、かつホットプレ-トににより100℃の温度で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 3)
A coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that 25 wt% sulfolane was used as a flame retardant and the hot plate was heated at a temperature of 100 ° C. for 20 minutes.
(比較例4)
難燃剤として25wt%のスルホランを用い、かつホットプレ-トにより100℃の温度で40分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 4)
A coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that 25 wt% sulfolane was used as a flame retardant and the battery was heated at a temperature of 100 ° C. for 40 minutes by a hot plate.
(比較例5)
難燃剤を添加せずに実施例3と同様な方法により電解質溶液を作製し、同実施例3と同様に電解質溶液をホットプレ-トにより50℃の温度で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 5)
An electrolyte solution was prepared by the same method as in Example 3 without adding a flame retardant, and the electrolyte solution was heated by a hot plate at a temperature of 50 ° C. for 20 minutes in the same manner as in Example 3, except that the same as in Example 1. A coin-type lithium-ion secondary battery was assembled by the same method.
(比較例6)
難燃剤を添加せず、実施例3と同様な方法により電解質溶液を作製し、同実施例3と同様に電解質溶液をホットプレ-トにより100℃の温度で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 6)
An electrolyte solution was prepared by the same method as in Example 3 without adding a flame retardant, and the electrolyte solution was heated by a hot plate at a temperature of 100 ° C. for 20 minutes in the same manner as in Example 3. A coin-type lithium-ion secondary battery was assembled by the same method.
(比較例7)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)3gと、THF25gとを混合し、さらにのLiN(SO2CF3)22.45gを加えた。このとき、ポリエチレンオキシド中のエ-テル酸素のモル濃度[EO]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比率(Li/EO)を8とした。得られたPEOとTHFとリチウム塩との混合物に、15wt%のトリメチルフォスフェ-ト(TMP)を難燃剤として加えて、電解質溶液を調製した。
次いで、前記電解質溶液を用い、ホットプレ-トにより50℃で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 7)
(1) Preparation of electrolyte solution 3 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 25 g of THF were mixed, and further LiN (SO 2 CF 3 ) 2 2.45 g was added. .. At this time, the molar ratio (Li / EO) of the molar concentration [EO] of ether oxygen in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 8. An electrolyte solution was prepared by adding 15 wt% trimethyl phosphate (TMP) as a flame retardant to the obtained mixture of PEO, THF and a lithium salt.
Next, a coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate.
(比較例8)
比較例7と同様な方法により電解質溶液を調製し、同比較例7と同様に電解質溶液をホットプレ-トにより50℃で20分加熱し、さらに難燃剤として25wt%のTMPを用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 8)
An electrolyte solution was prepared by the same method as in Comparative Example 7, the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate in the same manner as in Comparative Example 7, and 25 wt% TMP was used as a flame retardant. A coin-type lithium ion secondary battery was assembled by the same method as in Example 1.
(比較例9)
比較例7と同様な方法により電解質溶液を調製し、同比較例7と同様に電解質溶液をホットプレ-トにより50℃で10分加熱し、さらに難燃剤として15wt%のTMPを用いた以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 9)
An electrolyte solution was prepared by the same method as in Comparative Example 7, and the electrolyte solution was heated at 50 ° C. for 10 minutes by a hot plate in the same manner as in Comparative Example 7, and was further carried out except that 15 wt% TMP was used as a flame retardant. A coin-type lithium ion secondary battery was assembled by the same method as in Example 1.
(比較例10)
難燃剤を添加せずに比較例7と同様な方法により電解質溶液を調製し、同比較例7と同様に電解質溶液をホットプレ-トにより50℃で10分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 10)
The same as in Example 1 except that the electrolyte solution was prepared by the same method as in Comparative Example 7 without adding a flame retardant, and the electrolyte solution was heated at 50 ° C. for 10 minutes by a hot plate in the same manner as in Comparative Example 7. A coin-type lithium-ion secondary battery was assembled by the method.
(比較例11)
79,4質量%の正極活物質であるLiFePO4、10質量%のNASION型固体電解質(LICGC PW-01,オハラ製)と、0.6質量%の導電助剤であるカ-ボンナノチュ-ブと、10質量%の結着剤であるポリフッ化ビニリデン(PVDF)とをそれぞれ添加して混合した後、当該混合物に溶剤としてN-メチル-2-ピロリドン(NMP)を添加して正極スラリ-を調製した。つづいて、正極集電体である厚さ20μmのアルミニウム箔上に正極スラリ-を塗布し、80℃で12時間乾燥した。その後、その後、、ハンドプレスを用いて5MPaでプレスし、さらに打抜き加工して直径14mmの円形の正極を作製した。
次いで、リチウム箔を直径15mmの円形に打ち抜き、負極を作製した。セパレ-タは、ポリプロピレンの高分子多孔フィルムを用いた。非水電解液は、LiPF6をエチレンカ-ボネ-ト(EC)、ジメチルカ-ボネ-ト(DMC)の混合非水溶媒(体積比、EC:DMC=1:1)に1.0モル/L溶解させて調製した。
(Comparative Example 11)
79.4% by mass of positive electrode active material LiFePO 4 , 10% by mass of NASION type solid electrolyte (LICGC PW-01, manufactured by O'Hara), and 0.6% by mass of conductive aid carbon nanotube. After adding 10% by mass of polyvinylidene fluoride (PVDF), which is a binder, and mixing them, N-methyl-2-pyrrolidone (NMP) was added as a solvent to the mixture to prepare a positive electrode slurry. did. Subsequently, a positive electrode slurry was applied onto an aluminum foil having a thickness of 20 μm, which is a positive electrode current collector, and dried at 80 ° C. for 12 hours. Then, after that, it was pressed at 5 MPa using a hand press and further punched to prepare a circular positive electrode having a diameter of 14 mm.
Next, the lithium foil was punched into a circle with a diameter of 15 mm to prepare a negative electrode. As the separator, a polypropylene polymer porous film was used. The non-aqueous electrolyte solution is 1.0 mol / L of LiPF 6 in a mixed non-aqueous solvent (volume ratio, EC: DMC = 1: 1) of ethylene carbonate (EC) and dimethyl carbonate (DMC). Prepared by dissolving.
正極と、負極と、セパレ-タと、混合非水溶媒とを用いて、露点-50℃以下の雰囲気下、常法により組込み、収容し、図1に示すようなコイン型のリチウムイオン二次電池(2032型)を組立てた。 Using a positive electrode, a negative electrode, a separator, and a mixed non-aqueous solvent, they are incorporated and housed by a conventional method in an atmosphere with a dew point of -50 ° C or lower, and are coin-shaped lithium ion secondary as shown in FIG. The battery (2032 type) was assembled.
次に、得られたコイン型のリチウムイオン二次電池の性能を評価した。
「引火実験」
実施例1~6および比較例1~11で作製したゲル電解質を空気中にてライタ-で5秒以上引火して、燃焼が続く場合を「可燃」、燃焼が続かない場合を「難燃」とした。この結果を下記表1に示した。なお、表1には実施例1~7および比較例1~11のゲル電解質のモル比(ポリエチレンオキシドの酸素のモル濃度(O)とリチウム塩(LiFePO4)中のリチウムイオンのモル濃度(Li)のモル比(O/Li)および有機溶媒(THF)、難燃剤の配合量を併記する。
Next, the performance of the obtained coin-type lithium-ion secondary battery was evaluated.
"Ignition experiment"
The gel electrolytes prepared in Examples 1 to 6 and Comparative Examples 1 to 11 are ignited in air with a writer for 5 seconds or longer, and if combustion continues, it is "flammable", and if combustion does not continue, it is "flame retardant". And said. The results are shown in Table 1 below. In Table 1, the molar ratios of the gel electrolytes of Examples 1 to 7 and Comparative Examples 1 to 11 (molar concentration of oxygen in polyethylene oxide (O) and molar concentration of lithium ions in the lithium salt (LiFePO 4 ) (Li). ), The molar ratio (O / Li), the organic solvent (THF), and the blending amount of the flame retardant are also described.
[放電レ-ト特性試験]
実施例1~6及び比較例1~11のコイン型のリチウムイオン二次電池を用い、室温で以下の充放電条件に従って充放電を行って、放電レ-ト特性試験を行った。下記表2に各レ-ト毎の放電容量を示す。なお、表2に記載の「-」は放電レ-ト特性試験を実行できなかたことを示す。
[Discharge rate characteristic test]
Using the coin-type lithium ion secondary batteries of Examples 1 to 6 and Comparative Examples 1 to 11, charging and discharging were performed at room temperature according to the following charging and discharging conditions, and a discharge rate characteristic test was performed. Table 2 below shows the discharge capacity for each rate. In addition, "-" in Table 2 indicates that the discharge rate characteristic test could not be executed.
充放電条件
0.1C放電の放電試験:4.0Vまで0.1C充電、2.5Vまで0.1C放電。
0.5C放電の放電試験:4.0Vまで0.5C充電、2.5Vまで0.5C放電。
1C放電の放電試験:4.0Vまで1C充電、2.5Vまで1C放電。
2C放電の放電試験:4.0Vまで2C充電、2.5Vまで2C放電。
Charge / discharge conditions 0.1C discharge discharge test: 0.1C charge up to 4.0V, 0.1C discharge up to 2.5V.
0.5C discharge test: 0.5C charge up to 4.0V, 0.5C discharge up to 2.5V.
Discharge test of 1C discharge: 1C charge up to 4.0V, 1C discharge up to 2.5V.
Discharge test of 2C discharge: 2C charge up to 4.0V, 2C discharge up to 2.5V.
前記表1から明らかなように難燃剤を添加しない比較例1,2,5,6,10および11に用いるゲル電解質は、全て引火により燃焼が続けられた。
これに対し、モル比(O/Li)が5および1で難燃剤を10wt%以上添加した実施例1~6のゲル電解質は、難燃性を示した。
As is clear from Table 1, all of the gel electrolytes used in Comparative Examples 1, 2, 5, 6, 10 and 11 to which no flame retardant was added continued to burn due to ignition.
On the other hand, the gel electrolytes of Examples 1 to 6 having a molar ratio (O / Li) of 5 and 1 and a flame retardant added in an amount of 10 wt% or more showed flame retardancy.
一方、モル比(O/Li)が本発明の範囲(1~5)を超える8で、THFの配合量が20wt%以上の比較例9のゲル電解質は、難燃剤を15wt%の添加しても、難燃性を示さなかった。 On the other hand, in the gel electrolyte of Comparative Example 9 in which the molar ratio (O / Li) exceeds the range (1 to 5) of the present invention 8 and the amount of THF is 20 wt% or more, a flame retardant is added in an amount of 15 wt%. Also did not show flame retardancy.
前記表2から明らかなように非水溶媒(THF)の配合量がは20wt%~40wt%、難燃剤の配合量が10wt%~30wt%である実施例1~6のコイン型のリチウムイオン二次電池は各レ-ト放電において良好な放電容量を示した。特に、難燃剤の配合量が少ないゲル電解質を備える実施例2および6のコイン型のリチウムイオン二次電池は、従来の液体電解液を用いる比較例11のコイン型のリチウムイオン二次電池に近似した放電レ-ト性能を有することが確認された。 As is clear from Table 2, the amount of the non-aqueous solvent (THF) is 20 wt% to 40 wt%, and the amount of the flame retardant is 10 wt% to 30 wt%. The secondary battery showed good discharge capacity at each late discharge. In particular, the coin-type lithium-ion secondary batteries of Examples 2 and 6 provided with the gel electrolyte containing a small amount of the flame-retardant agent are similar to the coin-type lithium-ion secondary batteries of Comparative Example 11 using the conventional liquid electrolyte. It was confirmed that it had the same discharge rate performance.
表2の結果から難燃剤を含まないゲル電解質を備える比較例1,5のコイン型のリチウムイオン二次電池は、優れた放電特性を有するものの、引火により燃焼する、安全性の問題がある。 From the results in Table 2, the coin-type lithium-ion secondary batteries of Comparative Examples 1 and 5 provided with the gel electrolyte containing no flame retardant have excellent discharge characteristics, but have a safety problem of burning by ignition.
THFの配合量が20wt%未満のゲル電解質を備える比較例3、比較例4、比較例6-8のコイン型のリチウムイオン二次電池は、ゲル電解質の流動性が低いため、リチウムイオンの伝導率がまだ低く、0.1Cでの放電容量も低下することが確認された。 The coin-type lithium ion secondary batteries of Comparative Example 3, Comparative Example 4, and Comparative Example 6-8 provided with a gel electrolyte containing less than 20 wt% of THF have low fluidity of the gel electrolyte, so that lithium ions are conducted. It was confirmed that the rate was still low and the discharge capacity at 0.1 C also decreased.
モル比(O/Li)が本発明のモル比の範囲(1-5)を超える8である場合、THFの量を20wt%以上、難燃剤を15wt%配合しても燃えることが分かった(比較例9参照)。従って電気化学性能測定を実施しなかった。THF量を14wt%まで減らすと、難燃性が現われたが、0.1Cでの放電比容量が低下することが確認された(比較例7、8参照)。 When the molar ratio (O / Li) was 8, which exceeds the molar ratio range (1-5) of the present invention, it was found that even if the amount of THF was 20 wt% or more and the flame retardant was blended in 15 wt%, the mixture burned (1-5). See Comparative Example 9). Therefore, no electrochemical performance measurement was performed. When the amount of THF was reduced to 14 wt%, flame retardancy appeared, but it was confirmed that the discharge specific volume at 0.1 C decreased (see Comparative Examples 7 and 8).
モル比(O/Li)が1であるゲル電解質を備えた実施例4および比較例4のコイン型のリチウムイオン二次電池について、0.1Cでの充放電カ-ブを測定した。その結果を図2に示す。両例には溶媒の含有量が近くて、難燃性を示したものの(実施例4:38wt%,比較例3:36wt%)、この図2から明らかなようにTHFの配合量が20wt%を超える(THF:23wt%)のゲル電解質を備えた実施例4のリチウムイオン二次電池は、放電容量が多く、分極が小さくなることをわかる。 The charge / discharge curves at 0.1 C were measured for the coin-type lithium ion secondary batteries of Example 4 and Comparative Example 4 provided with the gel electrolyte having a molar ratio (O / Li) of 1. The results are shown in FIG. Although the content of the solvent was close to that of both examples and showed flame retardancy (Example 4: 38 wt%, Comparative Example 3: 36 wt%), as is clear from FIG. 2, the blending amount of THF was 20 wt%. It can be seen that the lithium ion secondary battery of Example 4 provided with a gel electrolyte exceeding (THF: 23 wt%) has a large discharge capacity and a small polarization.
1…リチウムイオン二次電池、2…正極、3…負極、4…セパレ-タ、7…ガスケット、21…正極集電体、22…正極層、31…負極集電体、32…負極層。 1 ... Lithium ion secondary battery, 2 ... Positive electrode, 3 ... Negative electrode, 4 ... Separator, 7 ... Gasket, 21 ... Positive electrode current collector, 22 ... Positive electrode layer, 31 ... Negative electrode current collector, 32 ... Negative electrode layer.
本発明は、主鎖においてO原子を含む高分子化合物、リチウム塩、還元安定性を有する非水溶媒および酸化安定性を有する難燃剤を含むリチウム二次電池用ゲル電解質である。高分子化合物中のエ-テル結合に由来する酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)は、1~5である。高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]は、質量%表示で20~40である。高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]は、質量%表示で10~30である。 The present invention is a gel electrolyte for a lithium secondary battery containing a polymer compound containing an O atom in the main chain, a lithium salt, a non-aqueous solvent having reduction stability, and a flame retardant having oxidative stability. The molar ratio (O / Li) of the molar concentration (O) of oxygen derived from the ether bond in the polymer compound and the molar concentration (Li) of lithium ions in the lithium salt is 1 to 5. The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%. The ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%.
<第1の実施形態>
第1の実施形態に係るリチウム二次電池用ゲル電解質は、主鎖においてO原子を含む高分子化合物、リチウム塩、還元安定性を有する非水溶媒および酸化安定性を有する難燃剤を含む。高分子化合物中のエ-テル結合に由来する酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)は、1~5である。高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]は、質量%表示で20~40である。高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]は、質量%表示で10~30である。
<First Embodiment>
The gel electrolyte for a lithium secondary battery according to the first embodiment contains a polymer compound containing an O atom in the backbone, a lithium salt, a non-aqueous solvent having reduction stability, and a flame retardant having oxidation stability. The molar ratio (O / Li) of the molar concentration (O) of oxygen derived from the ether bond in the polymer compound and the molar concentration (Li) of lithium ions in the lithium salt is 1 to 5. The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%. The ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%.
主鎖においてO原子を含む高分子化合物は、例えばエチレンオキシド構造を有する高分子化合物を挙げることができる。このような高分子化合物の具体的な例は、ポリエチレンオキサイド(PEO)、ポリエチレングリコ-ルジメチルエステル(PEGDME),ポリエチレングリコ-ル(PEG)、ポリエチレンカ-ボネート(PEC)等を挙げることができる。高分子化合物の重量平均分子量は、1,000~5,000,000であることが好ましい。 Examples of the polymer compound containing an O atom in the main chain include a polymer compound having an ethylene oxide structure. Specific examples of such polymer compounds include polyethylene oxide (PEO), polyethylene glycol dimethyl ester ( PEGDME ), polyethylene glycol (PEG), polyethylene carbonate (PEC) and the like. can. The weight average molecular weight of the polymer compound is preferably 1,000 to 5,000,000.
第1の実施形態によれば、高分子化合物中のエ-テル結合に由来する酸素のモル濃度(O)とリチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)、および高分子化合物およびリチウム塩の合計質量(A+B)に対する非水溶媒の質量(C)の比率[C/(A+B)]を特定化することによって、高分子化合物がリチウムイオンに配位するのみならず、非水溶媒もリチウムイオンに配位した特殊な錯体構造を形成することができる。その結果、高い還元安定性、リチウムイオン導電性および良好な流動性を有し、さらに電解質膜を作る必要がなく、取り扱いが容易なリチウム二次電池用ゲル電解質を得ることができる。
また、酸化安定性を有する難燃剤の配合にあたり、高分子化合物およびリチウム塩の合計質量(A+B)に対する難燃剤の質量(D)の比率[D/(A+B)]を特定化することによって、ゲル電解質本来の特性を損なうことなく、非水溶媒の保持性の高い液漏れ性に優れ、かつ高い酸化還元安定性、難揮発性と難燃性を有する安全なリチウム二次電池用ゲル電解質を得ることができる。
According to the first embodiment, the molar ratio (O / Li) of the molar concentration (O) of oxygen derived from the ether bond in the polymer compound and the molar concentration (Li) of the lithium ion in the lithium salt. ), And by specifying the ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt, the polymer compound coordinates with lithium ions. Not only that, a non-aqueous solvent can also form a special complex structure coordinated with lithium ions. As a result, it is possible to obtain a gel electrolyte for a lithium secondary battery which has high reduction stability, lithium ion conductivity and good fluidity, does not require the formation of an electrolyte membrane, and is easy to handle.
Further, when blending the flame-retardant agent having oxidation stability, the gel is specified by specifying the ratio [D / (A + B)] of the flame-retardant agent mass (D) to the total mass (A + B) of the polymer compound and the lithium salt. Obtains a safe gel electrolyte for lithium secondary batteries with high retention of non-aqueous solvent, excellent liquid leakage property, high redox stability, refractory volatility and flame retardancy without impairing the original characteristics of the electrolyte. be able to.
(実施例1)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)1gと、THF15gとを混合し、さらにLiN(SO2CF3)21.29gを加えた。このとき、ポリエチレンオキシド中のエ-テル結合に由来する酸素のモル濃度[O]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比(O/Li)を5とした。得られたPEOとTHFとリチウム塩との混合物に、15wt%のスルホラン(SL)を難燃剤として加えて、電解質溶液を調製した。
(Example 1)
(1) Preparation of electrolyte solution 1 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 15 g of THF were mixed, and Li N (SO 2 CF 3 ) 2 1.29 g was further added. .. At this time, the molar ratio (O / Li ) of the molar concentration [ O ] of oxygen derived from the ether bond in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 5. An electrolyte solution was prepared by adding 15 wt% sulfolane (SL) as a flame retardant to the obtained mixture of PEO, THF and a lithium salt.
(実施例2)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)1gと、テトラヒドロフラン(THF)15gとを混合し、さらにLiN(SO2CF3)26.45gを加えた。このとき、ポリエチレンオキシド中のエ-テル結合に由来する酸素のモル濃度[O]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比(O/Li)を1とした。得られたPEOとTHFとリチウム塩との混合物に、10wt%のTMPを難燃剤として加えて、電解質溶液を得た。
次いで、前記電解質溶液を用い、ホットプレ-トにより50℃で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Example 2)
(1) Preparation of electrolyte solution 1 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 15 g of tetrahydrofuran (THF) are mixed, and then LiN (SO 2 CF 3 ) 2 6.45 g. Was added. At this time, the molar ratio (O / Li ) of the molar concentration [ O ] of oxygen derived from the ether bond in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 1. To the obtained mixture of PEO, THF and a lithium salt, 10 wt% TMP was added as a flame retardant to obtain an electrolyte solution.
Next, a coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate.
(比較例7)
(1)電解質溶液の調製
重量平均分子量300,000のポリエチレンオキシド(PEO:Sigma-Aldrich社製)3gと、THF25gとを混合し、さらにLiN(SO2CF3)22.45gを加えた。このとき、ポリエチレンオキシド中のエ-テル結合に由来する酸素のモル濃度[O]とリチウム塩中のリチウムイオンのモル濃度[Li]とのモル比(O/Li)を8とした。得られたPEOとTHFとリチウム塩との混合物に、15wt%のトリメチルフォスフェ-ト(TMP)を難燃剤として加えて、電解質溶液を調製した。
次いで、前記電解質溶液を用い、ホットプレ-トにより50℃で20分加熱した以外、実施例1と同様な方法によりコイン型リチウムイオン二次電池を組立てた。
(Comparative Example 7)
(1) Preparation of electrolyte solution 3 g of polyethylene oxide (PEO: manufactured by Sigma-Aldrich) having a weight average molecular weight of 300,000 and 25 g of THF were mixed, and 2 2.45 g of Li N (SO 2 CF 3 ) was further added. .. At this time, the molar ratio (O / Li ) of the molar concentration [ O ] of oxygen derived from the ether bond in the polyethylene oxide and the molar concentration [Li] of the lithium ion in the lithium salt was set to 8. An electrolyte solution was prepared by adding 15 wt% trimethyl phosphate (TMP) as a flame retardant to the obtained mixture of PEO, THF and a lithium salt.
Next, a coin-type lithium ion secondary battery was assembled by the same method as in Example 1 except that the electrolyte solution was heated at 50 ° C. for 20 minutes by a hot plate.
次に、得られたコイン型のリチウムイオン二次電池の性能を評価した。
「引火実験」
実施例1~6および比較例1~11で作製したゲル電解質を空気中にてライタ-で5秒以上引火して、燃焼が続く場合を「可燃」、燃焼が続かない場合を「難燃」とした。この結果を下記表1に示した。なお、表1には実施例1~7および比較例1~11のゲル電解質のモル比(ポリエチレンオキシド中のエーテル結合に由来する酸素のモル濃度(O)とリチウム塩(LiN(SO
2
CF
3
)
2 )中のリチウムイオンのモル濃度(Li)のモル比(O/Li))および有機溶媒(THF)、難燃剤の配合量を併記する。
Next, the performance of the obtained coin-type lithium-ion secondary battery was evaluated.
"Ignition experiment"
The gel electrolytes prepared in Examples 1 to 6 and Comparative Examples 1 to 11 are ignited in air with a writer for 5 seconds or longer, and if combustion continues, it is "flammable", and if combustion does not continue, it is "flame retardant". And said. The results are shown in Table 1 below. In Table 1, the molar ratios of the gel electrolytes of Examples 1 to 7 and Comparative Examples 1 to 11 (molar concentration (O) of oxygen derived from ether bond in polyethylene oxide and lithium salt ( LiN (SO 2 CF 3 )) are shown. 2 ) The molar ratio (O / Li ) of the molar concentration (Li) of lithium ions in 2), the organic solvent (THF), and the blending amount of the flame retardant are also described.
Claims (5)
主鎖においてO原子を含む高分子化合物、リチウム塩、還元安定性を有する非水溶媒および酸化安定性を有する難燃剤を含み、
前記高分子化合物の繰り返し単位中の酸素のモル濃度(O)と前記リチウム塩の中のリチウムイオンのモル濃度(Li)とのモル比(O/Li)が1~5であり、
前記高分子化合物および前記リチウム塩の合計質量(A+B)に対する前記非水溶媒の質量(C)の比率[C/(A+B)]が質量%表示で20~40であり、
前記高分子化合物および前記リチウム塩の合計質量(A+B)に対する前記難燃剤の質量(D)の比率[D/(A+B)]が質量%表示で10~30であるリチウム二次電池用ゲル電解質。 A gel electrolyte for lithium secondary batteries,
It contains a polymer compound containing an O atom in the main chain, a lithium salt, a non-aqueous solvent having reduction stability, and a flame retardant having oxidative stability.
The molar ratio (O / Li) of the molar concentration (O) of oxygen in the repeating unit of the polymer compound and the molar concentration (Li) of lithium ions in the lithium salt is 1 to 5.
The ratio [C / (A + B)] of the mass (C) of the non-aqueous solvent to the total mass (A + B) of the polymer compound and the lithium salt is 20 to 40 in terms of mass%.
A gel electrolyte for a lithium secondary battery in which the ratio [D / (A + B)] of the mass (D) of the flame retardant to the total mass (A + B) of the polymer compound and the lithium salt is 10 to 30 in terms of mass%.
請求項1または2に記載のリチウム二次電池用ゲル電解質は、前記正極、前記負極および前記セパレ-タに含浸されるリチウム二次電池。 A lithium secondary battery including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode.
The gel electrolyte for a lithium secondary battery according to claim 1 or 2, is a lithium secondary battery impregnated in the positive electrode, the negative electrode and the separator.
正極、負極および正極と負極の間に配置されるセパレ-タを備えた発電要素を作製する工程と、
前記発電要素に前記ゲル電解液を注入する工程と、
前記ゲル電解液の注入後に放置し、前記ゲル電解液を前記正極、前記負極および前記セパレ-タに拡散させる工程と、
前記発電要素を加熱して前記ゲル電解液中の前記非水溶媒の一部を揮散させて前記発電要素の前記正極、前記負極および前記セパレ-タに請求項1または2に記載のリチウム二次電池用ゲル電解質を含浸させる工程と
を含むリチウム二次電池の製造方法。 The main chain contains a polymer compound containing an O atom, a lithium salt, a non-aqueous solvent and a flame retardant, and the non-aqueous solvent is relative to the total amount of the polymer compound, the lithium salt, the non-aqueous solvent and the flame retardant. In the process of preparing a gel electrolyte solution containing 70 to 80% by mass,
A process of manufacturing a power generation element having a positive electrode, a negative electrode, and a separator arranged between the positive electrode and the negative electrode, and
The step of injecting the gel electrolytic solution into the power generation element and
A step of diffusing the gel electrolytic solution into the positive electrode, the negative electrode and the separator by leaving the gel electrolytic solution after injection.
The lithium secondary according to claim 1 or 2, wherein the power generation element is heated to volatilize a part of the non-aqueous solvent in the gel electrolyte solution to the positive electrode, the negative electrode and the separator of the power generation element. A method for manufacturing a lithium secondary battery, which comprises a step of impregnating a gel electrolyte for a battery.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020206630A JP7031100B1 (en) | 2020-12-14 | 2020-12-14 | Gel electrolyte for lithium secondary battery, method for manufacturing lithium secondary battery and lithium secondary battery |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020206630A JP7031100B1 (en) | 2020-12-14 | 2020-12-14 | Gel electrolyte for lithium secondary battery, method for manufacturing lithium secondary battery and lithium secondary battery |
Publications (2)
Publication Number | Publication Date |
---|---|
JP7031100B1 JP7031100B1 (en) | 2022-03-08 |
JP2022093903A true JP2022093903A (en) | 2022-06-24 |
Family
ID=81212844
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2020206630A Active JP7031100B1 (en) | 2020-12-14 | 2020-12-14 | Gel electrolyte for lithium secondary battery, method for manufacturing lithium secondary battery and lithium secondary battery |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP7031100B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2024191260A1 (en) * | 2023-03-14 | 2024-09-19 | 에스케이온 주식회사 | Secondary battery electrolyte, manufacturing method therefor, and lithium secondary battery comprising same |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5110694A (en) * | 1990-10-11 | 1992-05-05 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Secondary Li battery incorporating 12-Crown-4 ether |
JP2014112526A (en) * | 2012-11-07 | 2014-06-19 | Yokohama National Univ | Secondary battery, and method of manufacturing secondary battery |
CN105703003A (en) * | 2016-01-29 | 2016-06-22 | 北京当代经典科技有限公司 | Comb-shaped polymer, electrolyte and composite electrode for lithium battery, and applications of electrolyte and composite electrode |
JP2017535927A (en) * | 2014-12-01 | 2017-11-30 | ブルー ソリューション | Organic lithium battery |
JP2018514929A (en) * | 2015-10-30 | 2018-06-07 | エルジー・ケム・リミテッド | Multi-layer polymer electrolyte and all-solid-state battery including the same |
WO2020045893A1 (en) * | 2018-08-31 | 2020-03-05 | 주식회사 엘지화학 | Solid electrolyte, method for preparing same, and all-solid-state battery including same |
CN111533864A (en) * | 2020-03-19 | 2020-08-14 | 闽南师范大学 | Block copolymer and preparation method thereof, and all-solid-state copolymer electrolyte membrane and preparation method thereof |
-
2020
- 2020-12-14 JP JP2020206630A patent/JP7031100B1/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5110694A (en) * | 1990-10-11 | 1992-05-05 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Secondary Li battery incorporating 12-Crown-4 ether |
JP2014112526A (en) * | 2012-11-07 | 2014-06-19 | Yokohama National Univ | Secondary battery, and method of manufacturing secondary battery |
JP2017535927A (en) * | 2014-12-01 | 2017-11-30 | ブルー ソリューション | Organic lithium battery |
JP2018514929A (en) * | 2015-10-30 | 2018-06-07 | エルジー・ケム・リミテッド | Multi-layer polymer electrolyte and all-solid-state battery including the same |
CN105703003A (en) * | 2016-01-29 | 2016-06-22 | 北京当代经典科技有限公司 | Comb-shaped polymer, electrolyte and composite electrode for lithium battery, and applications of electrolyte and composite electrode |
WO2020045893A1 (en) * | 2018-08-31 | 2020-03-05 | 주식회사 엘지화학 | Solid electrolyte, method for preparing same, and all-solid-state battery including same |
CN111533864A (en) * | 2020-03-19 | 2020-08-14 | 闽南师范大学 | Block copolymer and preparation method thereof, and all-solid-state copolymer electrolyte membrane and preparation method thereof |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2024191260A1 (en) * | 2023-03-14 | 2024-09-19 | 에스케이온 주식회사 | Secondary battery electrolyte, manufacturing method therefor, and lithium secondary battery comprising same |
Also Published As
Publication number | Publication date |
---|---|
JP7031100B1 (en) | 2022-03-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Wright et al. | Review on high temperature secondary Li-ion batteries | |
JP7116314B2 (en) | Electrolyte for non-aqueous electrolyte battery and non-aqueous electrolyte battery using the same | |
US10290902B2 (en) | Electrolyte for lithium metal battery, lithium metal battery including the electrolyte, and method of manufacturing the lithium metal battery | |
KR101607024B1 (en) | Lithium secondary battery | |
CN109565038B (en) | Method for pretreating lithium electrode and lithium metal battery | |
KR20190054920A (en) | Electrolyte for lithium secondary battery and lithium secondary battery comprising the same | |
EP1831951A2 (en) | Long life lithium batteries with stabilized electrodes | |
CN111448704B (en) | Electrolyte for nonaqueous electrolyte battery and nonaqueous electrolyte battery using same | |
CN102593511A (en) | A mixed solvent for an electrolyte for a lithium secondary battery and lithium secondary battery comprising the same | |
KR101440347B1 (en) | Anode Having Multi-Layer Structure for Secondary Battery and Lithium Secondary Battery Including The Same | |
KR101445602B1 (en) | Secondary Battery Having Improved Safety | |
JP2009199960A (en) | Lithium-ion battery | |
JP2010282906A (en) | Nonaqueous electrolyte for lithium ion secondary battery and lithium ion secondary battery | |
KR20130117689A (en) | The method of preparing electrodes for lithium secondary battery and the electrodes prepared by using the same | |
JP2019114323A (en) | Lithium secondary battery | |
JP7031100B1 (en) | Gel electrolyte for lithium secondary battery, method for manufacturing lithium secondary battery and lithium secondary battery | |
JP5708597B2 (en) | Non-aqueous electrolyte for lithium ion secondary battery and lithium ion secondary battery | |
JP5708598B2 (en) | Non-aqueous electrolyte for lithium ion secondary battery and lithium ion secondary battery | |
KR101578974B1 (en) | Positive-electrode active material, manufacturing method of the same, and nonaqueous electrolyte rechargeable battery having the same | |
CN117954689A (en) | Electrolyte for nonaqueous electrolyte battery and nonaqueous electrolyte battery using same | |
KR101470332B1 (en) | Functional Separator and Secondary Battery Comprising the Same | |
JP2020202158A (en) | Insulation layer, battery cell sheet, and battery cell | |
KR20150062822A (en) | Method for manufacturing secondary battery and secondary battery producted by the same method | |
JP7118479B2 (en) | Electrolyte for lithium secondary battery and lithium secondary battery containing the same | |
JP4787477B2 (en) | Non-aqueous electrolyte battery electrolyte additive, battery non-aqueous electrolyte and non-aqueous electrolyte battery |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20201214 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20211109 |
|
A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20211122 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20220125 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20220131 |
|
R150 | Certificate of patent or registration of utility model |
Ref document number: 7031100 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |