CN118589034A - Polymer electrolyte and preparation method and application thereof - Google Patents
Polymer electrolyte and preparation method and application thereof Download PDFInfo
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- CN118589034A CN118589034A CN202411067898.4A CN202411067898A CN118589034A CN 118589034 A CN118589034 A CN 118589034A CN 202411067898 A CN202411067898 A CN 202411067898A CN 118589034 A CN118589034 A CN 118589034A
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- 239000005518 polymer electrolyte Substances 0.000 title claims abstract description 119
- 238000002360 preparation method Methods 0.000 title claims abstract description 58
- 150000001875 compounds Chemical class 0.000 claims abstract description 153
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 45
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 45
- 229920000642 polymer Polymers 0.000 claims abstract description 25
- -1 tetrafluoroborate Chemical group 0.000 claims abstract description 19
- 238000007334 copolymerization reaction Methods 0.000 claims abstract description 14
- ZXMGHDIOOHOAAE-UHFFFAOYSA-N 1,1,1-trifluoro-n-(trifluoromethylsulfonyl)methanesulfonamide Chemical group FC(F)(F)S(=O)(=O)NS(=O)(=O)C(F)(F)F ZXMGHDIOOHOAAE-UHFFFAOYSA-N 0.000 claims abstract description 4
- OKVJWADVFPXWQD-UHFFFAOYSA-N difluoroborinic acid Chemical compound OB(F)F OKVJWADVFPXWQD-UHFFFAOYSA-N 0.000 claims abstract description 4
- KTQDYGVEEFGIIL-UHFFFAOYSA-N n-fluorosulfonylsulfamoyl fluoride Chemical group FS(=O)(=O)NS(F)(=O)=O KTQDYGVEEFGIIL-UHFFFAOYSA-N 0.000 claims abstract description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Inorganic materials [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 claims abstract description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical group OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 claims abstract description 4
- ITMCEJHCFYSIIV-UHFFFAOYSA-N triflic acid Chemical compound OS(=O)(=O)C(F)(F)F ITMCEJHCFYSIIV-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000002202 Polyethylene glycol Substances 0.000 claims description 29
- 229920001223 polyethylene glycol Polymers 0.000 claims description 29
- 239000003792 electrolyte Substances 0.000 claims description 25
- 229910052744 lithium Inorganic materials 0.000 claims description 21
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 claims description 18
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 16
- 239000003999 initiator Substances 0.000 claims description 14
- 238000006116 polymerization reaction Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 13
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 150000003254 radicals Chemical class 0.000 claims description 7
- OSSNTDFYBPYIEC-UHFFFAOYSA-N 1-ethenylimidazole Chemical compound C=CN1C=CN=C1 OSSNTDFYBPYIEC-UHFFFAOYSA-N 0.000 claims description 6
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 claims description 6
- 238000005342 ion exchange Methods 0.000 claims description 6
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 claims description 4
- 229910001486 lithium perchlorate Inorganic materials 0.000 claims description 4
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 3
- VDVLPSWVDYJFRW-UHFFFAOYSA-N lithium;bis(fluorosulfonyl)azanide Chemical compound [Li+].FS(=O)(=O)[N-]S(F)(=O)=O VDVLPSWVDYJFRW-UHFFFAOYSA-N 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 41
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 41
- 230000005012 migration Effects 0.000 abstract description 23
- 238000013508 migration Methods 0.000 abstract description 23
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 description 40
- 230000000052 comparative effect Effects 0.000 description 22
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 description 16
- 150000002500 ions Chemical class 0.000 description 15
- 125000003827 glycol group Chemical group 0.000 description 13
- 239000000203 mixture Substances 0.000 description 13
- 238000004132 cross linking Methods 0.000 description 12
- 239000007787 solid Substances 0.000 description 12
- 239000006183 anode active material Substances 0.000 description 11
- 239000011230 binding agent Substances 0.000 description 11
- 239000006258 conductive agent Substances 0.000 description 11
- 239000002608 ionic liquid Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 11
- 239000004014 plasticizer Substances 0.000 description 11
- 230000010287 polarization Effects 0.000 description 11
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 239000007774 positive electrode material Substances 0.000 description 9
- 239000010935 stainless steel Substances 0.000 description 8
- 229910001220 stainless steel Inorganic materials 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 239000000178 monomer Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000007784 solid electrolyte Substances 0.000 description 6
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 5
- OZAIFHULBGXAKX-VAWYXSNFSA-N AIBN Substances N#CC(C)(C)\N=N\C(C)(C)C#N OZAIFHULBGXAKX-VAWYXSNFSA-N 0.000 description 5
- 150000001450 anions Chemical class 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- LMBFAGIMSUYTBN-MPZNNTNKSA-N teixobactin Chemical compound C([C@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CO)C(=O)N[C@H](CCC(N)=O)C(=O)N[C@H]([C@@H](C)CC)C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CO)C(=O)N[C@H]1C(N[C@@H](C)C(=O)N[C@@H](C[C@@H]2NC(=N)NC2)C(=O)N[C@H](C(=O)O[C@H]1C)[C@@H](C)CC)=O)NC)C1=CC=CC=C1 LMBFAGIMSUYTBN-MPZNNTNKSA-N 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 210000004027 cell Anatomy 0.000 description 3
- 150000003949 imides Chemical class 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 2
- 229910013716 LiNi Inorganic materials 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- OPHUWKNKFYBPDR-UHFFFAOYSA-N copper lithium Chemical compound [Li].[Cu] OPHUWKNKFYBPDR-UHFFFAOYSA-N 0.000 description 2
- 239000003431 cross linking reagent Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 125000002897 diene group Chemical group 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000011244 liquid electrolyte Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- IAHFWCOBPZCAEA-UHFFFAOYSA-N succinonitrile Chemical compound N#CCCC#N IAHFWCOBPZCAEA-UHFFFAOYSA-N 0.000 description 2
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- LZDKZFUFMNSQCJ-UHFFFAOYSA-N 1,2-diethoxyethane Chemical compound CCOCCOCC LZDKZFUFMNSQCJ-UHFFFAOYSA-N 0.000 description 1
- VPBZZPOGZPKYKX-UHFFFAOYSA-N 1,2-diethoxypropane Chemical compound CCOCC(C)OCC VPBZZPOGZPKYKX-UHFFFAOYSA-N 0.000 description 1
- LEEANUDEDHYDTG-UHFFFAOYSA-N 1,2-dimethoxypropane Chemical compound COCC(C)OC LEEANUDEDHYDTG-UHFFFAOYSA-N 0.000 description 1
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- RRQYJINTUHWNHW-UHFFFAOYSA-N 1-ethoxy-2-(2-ethoxyethoxy)ethane Chemical compound CCOCCOCCOCC RRQYJINTUHWNHW-UHFFFAOYSA-N 0.000 description 1
- ZIKLJUUTSQYGQI-UHFFFAOYSA-N 1-ethoxy-2-(2-ethoxypropoxy)propane Chemical compound CCOCC(C)OCC(C)OCC ZIKLJUUTSQYGQI-UHFFFAOYSA-N 0.000 description 1
- ORRRIJVZQZKAKQ-UHFFFAOYSA-N 1-ethoxy-2-[2-(2-ethoxypropoxy)propoxy]propane Chemical compound CCOCC(C)OCC(C)OCC(C)OCC ORRRIJVZQZKAKQ-UHFFFAOYSA-N 0.000 description 1
- FXAFMVDJGZBDEP-UHFFFAOYSA-N 1-ethoxy-2-[2-[2-(2-ethoxypropoxy)propoxy]propoxy]propane Chemical compound CCOCC(C)OCC(C)OCC(C)OCC(C)OCC FXAFMVDJGZBDEP-UHFFFAOYSA-N 0.000 description 1
- RERATEUBWLKDFE-UHFFFAOYSA-N 1-methoxy-2-[2-(2-methoxypropoxy)propoxy]propane Chemical compound COCC(C)OCC(C)OCC(C)OC RERATEUBWLKDFE-UHFFFAOYSA-N 0.000 description 1
- ROSYHLFNMZTEKZ-UHFFFAOYSA-N 1-methoxy-2-[2-[2-(2-methoxypropoxy)propoxy]propoxy]propane Chemical compound COCC(C)OCC(C)OCC(C)OCC(C)OC ROSYHLFNMZTEKZ-UHFFFAOYSA-N 0.000 description 1
- HYDWALOBQJFOMS-UHFFFAOYSA-N 3,6,9,12,15-pentaoxaheptadecane Chemical compound CCOCCOCCOCCOCCOCC HYDWALOBQJFOMS-UHFFFAOYSA-N 0.000 description 1
- VATRWWPJWVCZTA-UHFFFAOYSA-N 3-oxo-n-[2-(trifluoromethyl)phenyl]butanamide Chemical compound CC(=O)CC(=O)NC1=CC=CC=C1C(F)(F)F VATRWWPJWVCZTA-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
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910011281 LiCoPO 4 Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910014689 LiMnO Inorganic materials 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910013086 LiNiPO Inorganic materials 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 239000006182 cathode active material Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 229940019778 diethylene glycol diethyl ether Drugs 0.000 description 1
- SBZXBUIDTXKZTM-UHFFFAOYSA-N diglyme Chemical compound COCCOCCOC SBZXBUIDTXKZTM-UHFFFAOYSA-N 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
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- SBWRUMICILYTAT-UHFFFAOYSA-K lithium;cobalt(2+);phosphate Chemical compound [Li+].[Co+2].[O-]P([O-])([O-])=O SBWRUMICILYTAT-UHFFFAOYSA-K 0.000 description 1
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 1
- LRVBJNJRKRPPCI-UHFFFAOYSA-K lithium;nickel(2+);phosphate Chemical compound [Li+].[Ni+2].[O-]P([O-])([O-])=O LRVBJNJRKRPPCI-UHFFFAOYSA-K 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920000379 polypropylene carbonate Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002153 silicon-carbon composite material Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229910001251 solid state electrolyte alloy Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- YFNKIDBQEZZDLK-UHFFFAOYSA-N triglyme Chemical compound COCCOCCOCCOC YFNKIDBQEZZDLK-UHFFFAOYSA-N 0.000 description 1
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)
Abstract
The invention provides a polymer electrolyte, a preparation method and application thereof, wherein the polymer electrolyte comprises a polymer and lithium salt, and the polymer comprisesThe compounds shown
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to a polymer electrolyte, a preparation method and application thereof.
Background
The electrolyte is an important component of a lithium secondary battery, and serves to transport ions and conduct current between the positive and negative electrodes. Compared with liquid electrolyte, the solid electrolyte has higher mechanical strength and stability, can effectively inhibit the growth of lithium dendrite, reduces the risk of battery short circuit, can keep good performance in a wider temperature range, has better temperature stability, has good chemical stability, is not easy to react with an electrode, and is beneficial to prolonging the cycle life of a battery. Polymer solid electrolyte is a widely used solid electrolyte, which has good flexibility and workability, and has been studied extensively. Polyethylene oxide (PEO) has wide sources and good compatibility with lithium salt, and is usually used as a main raw material of polymer solid electrolyte, however, the existing polyethylene oxide solid electrolyte still has the problems of low ionic conductivity, low lithium ion migration number, poor mechanical strength and the like in the use process, so that the rate capability, the cycle performance and the safety performance of the battery are poor.
Disclosure of Invention
The present invention provides a polymer electrolyte which has excellent ionic conductivity, lithium ion migration number and mechanical strength.
The invention also provides a preparation method of the polymer electrolyte, wherein the lithium salt is added before the compound shown in the formula I and the compound shown in the formula II are polymerized, so that the lithium salt is uniformly dispersed in a cross-linked body formed by polymerization, and the polymer electrolyte with excellent ion conductivity, lithium ion migration number and mechanical strength is obtained.
The invention also provides a battery which has excellent rate performance, cycle performance and safety performance due to the polymer electrolyte.
The invention also provides the electronic equipment, which has excellent multiplying power performance, cycle performance and safety performance in the use process due to the battery.
The invention provides a polymer electrolyte, which comprises a polymer and lithium salt, wherein the polymer comprises a compound shown in a formula I and a crosslinking body obtained by copolymerizing the compound shown in a formula II:
In the formula I, m is an integer selected from 2-20;
In the formula II, R is selected from bis (trifluoromethylsulfonyl) imide, bis (fluorosulfonyl) imide, perchlorate, tetrafluoroborate, dioxaborate, difluoroborate or trifluoromethylsulfonate, and n is selected from integers of 1-10.
The polymer electrolyte as described above, wherein the copolymerization molar ratio of the compound represented by the formula I and the compound represented by the formula II is (70 to 95): (5-30).
The polymer electrolyte is characterized in that the molar ratio of the sum of polyethylene glycol structural units in the compound shown in the formula I and the compound shown in the formula II to the lithium salt is (10-25): 1.
The polymer electrolyte as described above, wherein the lithium salt comprises one or more of lithium bis (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalato borate, lithium dioxaato borate, lithium perchlorate.
The invention also provides a preparation method of the polymer electrolyte, which comprises the following steps:
and adding a free radical initiator into a mixed system of the compound shown in the formula I, the compound shown in the formula II and the lithium salt to initiate polymerization reaction, so as to obtain the polymer electrolyte.
The preparation method as described above, wherein, the compound shown in the formula II is prepared by a method comprising the following steps:
1) Reacting 1-vinylimidazole with a compound represented by formula III to obtain a compound represented by formula IV;
in the formula III, X is selected from Cl, br or I;
2) Carrying out ion exchange reaction on a compound shown in a formula IV and LiR to obtain a compound shown in a formula II;
。
the preparation method comprises the steps of carrying out polymerization reaction at the temperature of 60-100 ℃ for 4-12 hours.
The invention also provides a battery comprising a positive electrode, a negative electrode and an electrolyte layer between the positive electrode and the negative electrode, wherein the electrolyte layer comprises a polymer electrolyte as described above.
The battery, wherein the thickness of the electrolyte layer is 20-50 μm.
The invention also provides an electronic device comprising a battery as described above.
The implementation of the invention has at least the following beneficial effects:
1) The polymer of the polymer electrolyte comprises a crosslinking body obtained by copolymerizing the compound shown in the formula I and the compound shown in the formula II, wherein a polyethylene glycol chain segment of the compound shown in the formula I is positioned on a side chain of the crosslinking body after copolymerization, so that the polymer electrolyte has better movement capability, can better conduct lithium ions, and can enable the crosslinking body to have lower crystallinity after copolymerization, thereby improving the ionic conductivity of the electrolyte. In addition, the compound shown in the formula II can also introduce an imidazole ion liquid unit into the crosslinking body, the imidazole ion liquid unit can adsorb anions in lithium salt through electrostatic action, the migration number of lithium ions is improved, the concentration polarization is reduced, and the rate capability of the battery is improved. The cross-linked body after copolymerization still keeps a proper content of polyethylene glycol chain segments, and the three-dimensional network structure of the cross-linked body can also enable the electrolyte to have higher mechanical strength, so that the electrolyte has good flexibility and mechanical strength, has good compatibility with positive and negative interfaces, reduces interface impedance, and can avoid contact short circuits between the positive electrode and the negative electrode, thereby improving the cycle performance and the safety performance of the battery. In conclusion, the polymer electrolyte provided by the application has higher ion conductivity, lithium ion migration number and mechanical strength, and the battery comprising the polymer electrolyte has excellent cycle performance, safety performance and rate capability.
2) According to the preparation method of the polymer electrolyte, disclosed by the invention, the lithium salt is added before the compound shown in the formula I and the compound shown in the formula II are polymerized, so that the compound shown in the formula I and the compound shown in the formula II can dissolve the lithium salt on one hand, and the lithium salt can be uniformly dispersed in a crosslinked body formed by polymerization after the compound shown in the formula I and the compound shown in the formula II are added before the polymerization, and the polymer electrolyte with excellent ion conductivity, lithium ion migration number and mechanical strength is obtained.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The PEO molecular chain has a relatively high dielectric constant, can dissolve a plurality of lithium salts, and is a recognized matrix suitable for preparing all-solid-state electrolytes. However, pure PEO polymers tend to crystallize, resulting in fewer amorphous structures that can conduct lithium ions, which in turn results in lower ionic conductivity of the solid state electrolyte. In order to increase the ionic conductivity, the use temperature can be increased to reduce the crystallinity of the PEO polymer, but the mechanical strength of the electrolyte is also reduced after the crystallinity is reduced, so that the anode and the cathode are easy to contact and short-circuit. In addition, the principle of PEO conducting lithium ions is that the ion is coordinated with lithium ions through lone pair electrons in molecular chain oxygen atoms, so that the lithium ions are transmitted, but anions in lithium salts cannot act with polymers, so that the transmission capacity of the anions under an electric field is stronger than that of the lithium ions, the migration number of the lithium ions is lower, concentration polarization easily occurs in the charge and discharge process of a battery correspondingly, the problem of uneven deposition of the lithium ions and the like is solved, and finally the safety performance, the rate capability and the cycle performance of the battery are poorer.
Based on this, the invention provides a polymer electrolyte, comprising a polymer and a lithium salt, wherein the polymer comprises a crosslinked body obtained by copolymerizing a compound shown in a formula I and a compound shown in a formula II:
In the formula I, m is an integer selected from 2-20;
In the formula II, R is selected from bis (trifluoromethylsulfonyl) imide, bis (fluorosulfonyl) imide, perchlorate, tetrafluoroborate, dioxaborate, difluoroborate or trifluoromethylsulfonate, and n is selected from integers of 1-10.
The compound shown in the formula I is an acrylic ester compound containing a polyethylene glycol chain segment, the compound shown in the formula II is a compound obtained by adopting vinyl imidazole to chemically modify the polyethylene glycol chain segment, and the two ends of the compound contain two double bonds to play a role of a crosslinking agent, so that the compound and the compound can be crosslinked to form a crosslinked body with a three-dimensional network structure after being copolymerized with the compound shown in the formula I.
On one hand, the polyethylene glycol chain segment of the compound shown in the formula I is positioned on the side chain of the crosslinked body after copolymerization, has better movement capability and can better conduct lithium ions, and on the other hand, the copolymerization can also enable the crosslinked body to have lower crystallinity, so that the ionic conductivity of the electrolyte is improved through the functions of the two aspects.
Through introducing imidazole type ionic liquid units into the crosslinking body, anions in lithium salt can be adsorbed through electrostatic action, the migration number of lithium ions is improved, concentration polarization is reduced, and the rate capability of the battery is improved. In addition, the imidazole ionic liquid unit is embedded into the compound shown in the formula II, and the imidazole ionic liquid unit is not directly copolymerized with the compound shown in the formula I by adopting the cross-linking agent of the imidazole ionic liquid with the diene group, so that when the imidazole ionic liquid monomer containing the diene group is copolymerized with the compound shown in the formula I, the polarity difference of the imidazole ionic liquid monomer and the compound is overlarge, the phase separation phenomenon easily occurs, the obtained polymer is similar to a salt compound, the glass transition temperature and the crystallization melting temperature are higher, the lithium ion conduction is not facilitated, and the imidazole ionic liquid is introduced into the head end and the tail end of a polyethylene glycol chain segment, so that the compound shown in the formula II and the compound shown in the formula I have similar polarities, the phase separation during the copolymerization of the imidazole ionic liquid monomer and the compound shown in the formula I is avoided, and the obtained polymer can keep lower glass transition temperature and crystallization melting temperature, and the lithium ion conduction is facilitated.
The cross-linked body obtained after copolymerization still contains polyethylene glycol chain segments with proper content distribution, so that the electrolyte has good flexibility, has good compatibility with positive and negative interfaces, is favorable for reducing interface resistance and improves the cycle performance of the battery.
Compared with a linear polymer molecular structure, the three-dimensional network structure of the cross-linked body can enable the polymer electrolyte to have higher mechanical strength, and even if the cross-linked body is applied to a lithium metal solid-state battery with a positive electrode with higher surface density, the cross-linked body is not easy to cause contact short circuit of positive and negative electrodes, so that the battery has excellent energy density and safety performance.
In summary, the polymer electrolyte comprises the crosslinked body obtained by copolymerizing the compound shown in the formula I and the compound shown in the formula II, so that the polymer electrolyte has higher ion conductivity, lithium ion migration number and mechanical strength, and further the battery has excellent energy density, rate capability, cycle performance and safety performance.
In a preferred embodiment, the copolymerization molar ratio of the compound of formula I to the compound of formula II is (70-95): (5-30). Illustratively, the copolymerization molar ratio of the compound of formula I to the compound of formula II may be 70:30, 80:20, 90:10, 95:5, etc.
It should be noted that, the molar ratio of copolymerization in the present invention can be controlled by the compound shown in formula I and the feed ratio shown in formula II. For example, a copolymerization molar ratio of the compound of formula I to the compound of formula II of 70:30 can be achieved by controlling the feed molar ratio of the compound of formula I to the compound of formula II of 70:30.
When the content of the compound shown in the formula II is low, the obtained crosslinked body has low strength, the battery has a short-circuit prevention line and is unfavorable for the promotion of the ion migration number, and when the content of the compound shown in the formula II is high, the obtained crosslinked body has high rigidity, is not good in contact with the anode and the cathode, and can also cause the ion conductivity of the electrolyte to be low.
As described above, the oxygen atom in the polyethylene glycol segment can promote the conduction of lithium ions, and based on the research on the amount ratio of the polyethylene glycol segment to the lithium salt in the polymer, the invention finds that the electrolyte can have higher ion conductivity when the molar ratio of the polyethylene glycol segment to the lithium salt in the polymer is (10 to 25): 1. Illustratively, the molar ratio of polyethylene glycol segments to lithium salt may be in the range of 10:1, 13:1, 15:1, 18:1, 20:1, 23:1, 25:1, or any two molar ratios above.
The kind of the lithium salt is not particularly limited in the present invention, and may be one or more selected from lithium bistrifluoromethylsulfonyl imide, lithium bistrifluorosulfonyl imide, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalato borate, lithium dioxaato borate, and lithium perchlorate.
The invention also provides a preparation method of the polymer electrolyte, which comprises the following steps:
and adding a free radical initiator into a mixed system of the compound shown in the formula I, the compound shown in the formula II and the lithium salt to initiate polymerization reaction, so as to obtain the polymer electrolyte.
According to the preparation method, the free radical initiator is added into a mixed system of the compound shown in the formula I, the compound shown in the formula II and the lithium salt, in-situ polymerization of the compound shown in the formula I and the compound shown in the formula II is initiated in the process of preparing the electrolyte, and the lithium salt is uniformly distributed in the crosslinked body while a crosslinked body is formed, so that the polymer electrolyte with excellent ion conductivity, lithium ion migration number and mechanical strength is obtained.
The compounds of formula I may be obtained commercially or prepared by themselves using techniques well known in the art.
The compounds of formula II may be prepared by methods conventional in the art, for example, by methods comprising the steps of:
1) Reacting 1-vinylimidazole with a compound represented by formula III to obtain a compound represented by formula IV;
in the formula III, X is selected from Cl, br or I;
2) Carrying out ion exchange reaction on a compound shown in a formula IV and LiR to obtain a compound shown in a formula II;
。
The 1-vinylimidazole in step 1) and the compound of formula III are both commercially available or are synthesized by known means, and the reaction between them can be carried out without adding solvent according to a ratio of at least 2: and (3) mixing the materials according to the molar ratio of 1, and reacting at the reaction temperature of 60-100 ℃ for 4-12 hours.
The ion exchange reaction in step 2) may be carried out with reference to the following specific operations:
And (3) dissolving the compound shown in the formula IV in deionized water to obtain an aqueous solution of the compound shown in the formula IV, dropwise adding the aqueous solution into the aqueous solution of LiR, stirring to fully perform an ion exchange reaction, pouring out excessive water after the precipitate is completely separated out, and washing and drying to obtain the compound shown in the formula II.
Wherein R in LiR is defined as in the compound of formula II.
The radical initiator used in the polymerization reaction is not particularly limited in the present invention, and may be selected from radical initiators conventionally used in the art, including but not limited to peroxy radical initiators, azo-based initiators or photoinitiators.
Further, the amount of the free radical initiator may be 0.5% to 5% of the total mass of the compound represented by formula I and the compound represented by formula II.
The crosslinking reaction can realize crosslinking curing through heating, and can also realize crosslinking curing under the condition of ultraviolet irradiation, preferably, the crosslinking curing is realized under the heating condition, the heating temperature can be 50-80 ℃, and the time is 1-5 h.
The invention also provides a battery comprising a positive electrode, a negative electrode and an electrolyte layer between the positive electrode and the negative electrode, wherein the electrolyte layer comprises a polymer electrolyte as described above.
The polymer electrolyte has high ionic conductivity, lithium ion migration number and mechanical strength, so that the battery also has excellent rate performance, cycle performance and safety performance.
The electrolyte layer of the present invention may be a solid electrolyte including only the above polymer electrolyte, or may be a semi-solid battery obtained by mixing the above polymer electrolyte with a liquid electrolyte, and accordingly, the obtained battery may be either a semi-solid battery or a solid battery.
It can be understood that the greater the thickness of the electrolyte layer, the better the safety performance of the battery, but the greater the thickness will also increase the resistance to lithium ion transport, resulting in an increase in the battery resistance, degrading the rate capability of the battery, and also degrading the energy density of the battery. In view of the above, the thickness of the electrolyte layer is preferably 20 to 50 μm. The thickness of the electrolyte layer may be, for example, 20 μm,25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or any two values thereof.
The positive electrode and the negative electrode of the present invention can be both made with reference to positive and negative electrode compositions conventional in the art.
Specifically, the positive electrode includes a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector.
The composition of the positive electrode current collector is not particularly limited in the present invention, and may be selected from positive electrode current collectors conventionally used in the art, such as aluminum foil.
In a specific embodiment, the positive electrode active material layer includes a positive electrode active material, a conductive agent, a binder, a lithium salt, and a plasticizer.
The kind of the positive electrode active material, the conductive agent, the binder, the lithium salt and the plasticizer in the present invention is not particularly limited, and may be selected from those conventionally used in the art.
Specifically, the positive electrode active material may be selected from one or more of lithium cobaltate (LiCoO 2), lithium nickelate (LiNiO 2), lithium iron phosphate (LiFePO 4), lithium cobalt phosphate (LiCoPO 4), lithium manganese phosphate (LiMnPO 4), lithium nickel phosphate (LiNiPO 4), lithium manganate (LiMnO 2), binary material LiNi xA(1-x)O2 (a is selected from one of Co, mn, 0< x < 1), ternary material LiNi mBnC(1-m-n)O2 (B, C is independently selected from at least one of Co, al, mn, and B and C are different, 0< m <1,0< n < 1).
The conductive agent may be one or more selected from acetylene black, super P, super S, graphene, carbon fiber, carbon nanotube and ketjen black.
The binder may be selected from one or more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, polyacrylonitrile, polypropylene carbonate, styrene butadiene rubber, nitrile butadiene rubber, sodium carboxymethyl cellulose, polyethylene oxide, and ethylene oxide-propylene oxide copolymer.
The plasticizer may be selected from one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, tetraethylene glycol diethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol diethyl ether, tetrapropylene glycol diethyl ether, 1, 3-dioxolane, 1, 4-dioxane, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, succinonitrile, adiponitrile.
The choice of lithium salt may be referred to as the choice of lithium salt in the polymer electrolyte, and will not be described here.
In a preferred embodiment, the mass ratio of the positive electrode active material, the conductive agent, the binder, the lithium salt and the plasticizer in the positive electrode active material layer is (50 to 90): (1-10): (9-20): (0-10): (0-10).
The anode includes an anode current collector and an anode active material layer provided on at least one surface of the anode current collector.
The composition of the negative electrode current collector is not particularly limited in the present invention, and may be selected from negative electrode current collectors conventionally used in the art, such as copper foil.
In a specific embodiment, the anode active material layer includes an anode active material, a conductive agent, a binder, a lithium salt, and a plasticizer.
The kind of the negative electrode active material, the conductive agent, the binder, the lithium salt and the plasticizer in the present invention is not particularly limited, and may be selected from those conventionally used in the art.
Specifically, the negative electrode active material may be selected from lithium metal, lithium metal alloy, graphite, silicon oxide, silicon carbon composite, or silicon alloy. When the anode active material is selected from lithium metal and lithium metal alloy, the anode active material layer does not contain a conductive agent, a binder, a lithium salt, a plasticizer, and the like.
The kinds of the conductive agent, the binder, the lithium salt and the plasticizer in the anode active material layer may be referred to as the selection of the conductive agent, the binder, the lithium salt and the plasticizer in the cathode active material layer, and will not be described in detail herein.
In a preferred embodiment, the mass ratio of the anode active material, the conductive agent, the binder, the lithium salt and the plasticizer in the anode active material layer is (50 to 90): (1-10): (9-20): (0-10): (0-10).
The preparation method of the battery is not particularly limited, and it may be prepared by referring to a conventional method in the art.
For example, in one specific embodiment, a battery may be prepared by:
1) Dispersing an anode active material, a conductive agent, a binder, lithium salt and a plasticizer in a solvent according to a specific mass ratio to form anode active material layer slurry, coating the anode active material layer slurry on an anode current collector, and drying to obtain an anode;
2) Compounding metal lithium on a negative electrode current collector to obtain a negative electrode;
3) And assembling the positive electrode, the polymer electrolyte and the negative electrode in sequence to obtain a battery core, and packaging the battery core to obtain the battery.
The invention also provides an electronic device comprising a battery as described above. The invention is not particularly limited to electronic equipment, and can be any electric equipment comprising the battery, including but not limited to mobile phones, notebook computers, electric bicycles, electric automobiles, electric toys, energy storage equipment and the like.
The polymer electrolyte provided by the invention, the preparation method and application thereof will be described in further detail by specific examples.
Unless otherwise indicated, reagents, materials and equipment used in the examples below are conventional in the art, conventional materials and conventional equipment, and are commercially available, and the reagents involved can also be obtained synthetically by methods conventional in the art.
In the following examples, compounds of formula III-1, formula III-2, formula III-3, formula III-5, formula I-1, formula I-2, formula I-3, formula I-4, formula I-5, formula b are all available from Sigma Aldrich.
Example 1
The present example provides a polymer electrolyte and an all-solid-state battery, which are prepared as follows:
1. Preparation of Polymer electrolyte
1) Uniformly mixing 1-vinylimidazole and a compound shown in a formula III-1 in a round-bottom flask according to a molar ratio of 2.1:1, and heating to 60 ℃ for reaction for 4 hours to obtain a mixed solution.
2) Dissolving the mixed solution in deionized water, dropwise adding the obtained solution into an aqueous solution of LiTFSI, stirring for 4h to fully perform ion exchange reaction, pouring out excessive water, washing the precipitate with water for three times, and drying to obtain the compound shown in the formula II-1.
3) Mixing a compound shown in a formula I-1 and a compound shown in a formula II-1 according to a molar ratio of 80:20 to obtain a mixture, adding LiTFSI into the mixture according to a molar ratio of 18:1 of the sum of polyethylene glycol structural units in the compound shown in the formula I-1 and the compound shown in the formula II-1, adding AIBN accounting for 0.5 percent of the total mass of the compound shown in the formula I-1 and the compound shown in the formula II-1 as an initiator, and heating to 60 ℃ to polymerize for 4 hours to obtain the polymer electrolyte.
2. Preparation of all-solid-state battery
1) Uniformly mixing lithium iron phosphate, super P, polyethylene oxide with a molecular weight of 60 ten thousand, lithium bistrifluoromethylsulfonyl imide and succinonitrile in a mass ratio of 78:2:10:5:5 in N, N-dimethylformamide to obtain positive electrode active material layer slurry, coating the positive electrode active material layer slurry on an aluminum current collector with a thickness of 15 mu m by using a scraper, drying at 60 ℃ for 1h, and drying at 80 ℃ for 3h to obtain a positive electrode with a thickness of 75 mu m, wherein the surface loading amount of the lithium iron phosphate is 15mg/cm 2.
2) The positive electrode prepared above was cut into 4.5X6 cm 2, a lithium copper composite tape having a thickness of 25 μm (a thickness of a lithium layer: 15 μm, a thickness of a copper layer: 10 μm) was used as a negative electrode and cut into 4.7X16.2 cm 2, and the polymer electrolyte prepared above was cut into a size of 4.8X16.3 cm 2, a thickness of 40 μm. And (3) assembling the battery cells in the glove box filled with argon (the O 2 content is less than or equal to 0.5 ppm and the H 2 O content is less than or equal to 0.5 ppm) according to the sequence of the anode, the polymer electrolyte and the lithium copper composite belt, and packaging to obtain the all-solid-state battery.
Example 2
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in their preparation methods, except that in the preparation of the polymer electrolyte, in step 3), the molar ratio of the compound represented by formula I-1 to the compound represented by formula II-1 is replaced with 90:10.
Example 3
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in their preparation methods, except that in the preparation of the polymer electrolyte, in step 3), the molar ratio of the compound represented by formula I-1 to the compound represented by formula II-1 is replaced with 70:30.
Example 4
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in their preparation methods, except that in the preparation of the polymer electrolyte, in step 3), the molar ratio of the compound represented by formula I-1 to the compound represented by formula II-1 is replaced with 60:40.
Example 5
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in their preparation method, except that in the preparation of the polymer electrolyte, in step 3), the compound represented by formula I-1 is replaced with the compound represented by formula I-2.
Example 6
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in their preparation method, except that in the preparation of the polymer electrolyte, in step 3), the compound represented by formula I-1 is replaced with the compound represented by formula I-3.
Example 7
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the compound represented by formula III-1 in step 1) is replaced with the compound represented by formula III-2, and correspondingly, the compound represented by formula II-2 is obtained in step 2), and the compound represented by formula II-1 is replaced with the compound represented by formula II-2 in step 3).
Example 8
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the compound represented by formula III-1 in step 1) is replaced with the compound represented by formula III-3, and correspondingly, the compound represented by formula II-3 is obtained in step 2), and the compound represented by formula II-1 is replaced with the compound represented by formula II-3 in step 3).
Example 9
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the molar ratio of the sum of polyethylene glycol structural units in the compound represented by formula I-1 and the compound represented by formula II-1 to LiTFSI in step 3) is replaced with 10:1.
Example 10
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the molar ratio of the sum of polyethylene glycol structural units in the compound represented by formula I-1 and the compound represented by formula II-1 to LiTFSI in step 3) is replaced with 25:1.
Example 11
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the molar ratio of the sum of polyethylene glycol structural units in the compound represented by formula I-1 and the compound represented by formula II-1 to LiTFSI in step 3) is replaced with 8:1.
Example 12
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that in the preparation of the polymer electrolyte, the molar ratio of the sum of polyethylene glycol structural units in the compound represented by formula I-1 and the compound represented by formula II-1 to LiTFSI in step 3) is replaced with 30:1.
Example 13
This example provides a polymer electrolyte and an all-solid battery, which were basically identical in preparation method to example 1, except that the thickness of the polymer electrolyte was replaced with 20 μm in the preparation of the all-solid battery.
Example 14
This example provides a polymer electrolyte and an all-solid battery, which were basically identical in preparation method to example 1, except that the thickness of the polymer electrolyte was replaced with 50 μm in the preparation of the all-solid battery.
Example 15
This example provides a polymer electrolyte and an all-solid battery, which were basically identical in preparation method to example 1, except that the thickness of the polymer electrolyte was replaced with 15 μm in the preparation of the all-solid battery.
Example 16
This example provides a polymer electrolyte and an all-solid battery, which were basically identical in preparation method to example 1, except that the thickness of the polymer electrolyte was replaced with 60 μm in the preparation of the all-solid battery.
Example 17
This example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in the preparation method thereof, except that LiTFSI in both step 2) and step 3) is replaced with lithium perchlorate in the preparation of the polymer electrolyte, a compound represented by formula II-4 is obtained in step 2), and a compound represented by formula II-1 is replaced with a compound represented by formula II-4 in step 3).
Comparative example 1
This comparative example provides a polymer electrolyte and an all-solid-state battery, the polymer electrolyte is prepared as follows:
Mixing the compound shown in the formula I-1 with LiTFSI according to the mol ratio of polyethylene glycol structural unit to LiTFSI of 18:1, adding AIBN accounting for 0.5 percent of the mass of the compound shown in the formula I-1 into the mixture as an initiator, and heating to 60 ℃ for polymerization for 4 hours to obtain the polymer electrolyte.
The preparation method of the all-solid-state battery is described with reference to example 1.
Comparative example 2
This comparative example provides a polymer electrolyte and an all-solid-state battery, the polymer electrolyte is prepared as follows:
Steps 1) and 2) are consistent with example 1, step 3) being replaced by: mixing the compound shown in the formula II-1 with LiTFSI according to the mol ratio of polyethylene glycol structural unit to LiTFSI of 18:1, adding AIBN accounting for 0.5 percent of the mass of the compound shown in the formula II-1 into the mixture as an initiator, and heating to 60 ℃ for polymerization for 4 hours to obtain the polymer electrolyte.
The preparation method of the all-solid-state battery is described with reference to example 1.
Comparative example 3
This comparative example provides a polymer electrolyte and an all-solid-state battery, the polymer electrolyte is prepared as follows:
1) With reference to the preparation of formula II-1 in example 1, the starting material of formula III-1 is replaced by Preparing a compound shown in a formula a;
2) Mixing a compound shown in a formula a and a compound shown in a formula b according to a molar ratio of 80:20 to obtain a mixture, adding LiTFSI into the mixture according to a molar ratio of 18:1 of polyethylene glycol structural units to LiTFSI in the mixture, adding AIBN accounting for 0.5% of the total mass of the compound shown in the formula a and the compound shown in the formula b as an initiator into the mixture, and heating to 60 ℃ to polymerize for 4 hours to obtain the polymer electrolyte.
The preparation method of the all-solid-state battery is described with reference to example 1.
Comparative example 4
This comparative example provides a polymer electrolyte and an all-solid-state battery, the polymer electrolyte is prepared as follows:
Mixing a compound shown in a formula I-1 with a compound shown in a formula b according to a molar ratio of 80:20 to obtain a mixture, adding LiTFSI into the mixture according to a molar ratio of polyethylene glycol structural units to LiTFSI of 18:1, adding AIBN accounting for 0.5% of the total mass of the compound shown in the formula I-1 and the compound shown in the formula b as an initiator, and heating to 60 ℃ for polymerization for 4 hours to obtain the polymer electrolyte.
Comparative example 5
This comparative example provides a polymer electrolyte and an all-solid-state battery, which are basically identical in preparation method to example 1, except that in the preparation of the polymer electrolyte, in step 3), the compound represented by formula I-1 is replaced with the compound represented by formula I-4.
Comparative example 6
This comparative example provides a polymer electrolyte and an all-solid-state battery, which are basically identical in preparation method to example 1, except that in the preparation of the polymer electrolyte, in step 3), the compound represented by formula I-1 is replaced with the compound represented by formula I-5.
Comparative example 7
This comparative example provides a polymer electrolyte and an all-solid-state battery, which are basically identical to example 1 in preparation method, except that in the preparation of the polymer electrolyte, the compound represented by formula III-1 in step 1) is replaced with the compound represented by formula III-5, and correspondingly, the compound represented by formula II-5 is obtained in step 2), and the compound represented by formula II-1 is also replaced with the compound represented by formula II-5 in step 3).
Test case
1. The polymer electrolytes prepared in the above examples and comparative examples were subjected to the following performance tests
1. Number of lithium ion migration
The testing method comprises the following steps: the lithium sheet with the diameter of 16mm is used as an electrode, the polymer electrolyte is cut into a wafer with the diameter of 19mm, the wafer is assembled into a Li symmetric battery, and the Li symmetric battery is tested for the migration number of lithium ions and the ion conductivity. And applying 10mV polarization voltage to the battery by using an electrochemical workstation, wherein the polarization time is 2h, testing the current and impedance of the symmetrical battery before and after polarization, and calculating the migration number of lithium ions according to the following formula.
Wherein t + is the lithium ion migration number, I 0 and I ss are the current before the start of polarization and the current after the stabilization of polarization, R 0 and R ss are the impedance before the start of polarization and the impedance after the stabilization of polarization, respectively, and y is the polarization voltage.
2. Ion conductivity
The testing method comprises the following steps: cutting stainless steel sheets with the diameter of 16mm and the thickness of 200 mu m and polymer electrolyte membranes with the diameter of 19mm respectively by using a sheet punching machine; and sequentially stacking the obtained stainless steel sheets and the polymer electrolyte membrane to ensure that the polymer electrolyte membrane is positioned between the stainless steel sheets, and assembling to obtain the stainless steel symmetrical battery. The impedance of the stainless steel symmetrical cell was tested after placing the stainless steel symmetrical cell in an oven at 60 ℃ for 10 minutes.
The ionic conductivity of the polymer electrolyte was calculated according to the following formula:
wherein sigma is the ionic conductivity of the electrolyte, L is the thickness of the polymer electrolyte membrane, S is the area of the stainless steel sheet, and R is the impedance of the stainless steel symmetrical battery.
The above test results are shown in table 1.
2. The following performance tests were conducted on all solid-state batteries prepared in the above examples and comparative examples
1. Cycle performance
The testing method comprises the following steps: the battery is charged to 3.8V at a constant current with a multiplying power of 0.05C at 60 ℃, kept stand for 5min, discharged to 2.5V with a constant current with a multiplying power of 0.05C, and the above process is circulated for 3 times. Then charging to 3.8V at a rate of 0.2C, and charging to 0.01C at a constant voltage of 3.8V, standing for 5min, discharging to 2.5V at a rate of 0.2C, standing for 5min, stopping when the specific capacity of the battery is 80% of the initial capacity, and recording the cycle number at the moment.
2. Rate capability
The testing method comprises the following steps: the battery is charged to 3.8V at a constant current with a multiplying power of 0.05C at 60 ℃, kept stand for 5min, discharged to 2.5V with a constant current with a multiplying power of 0.05C, and the above process is circulated for 3 times. Then, the battery was charged to 3.8V at a rate of 0.1C, was left to stand for 5 minutes, was discharged to 2.5V at a rate of 0.1C, was left to stand for 5 minutes, was charged to 3.8V at a rate of 0.5C, was recorded with charge capacities of 0.5C and 0.1C, and was calculated from the charge capacity of 0.5C/charge capacity of 0.1C to obtain a charge capacity retention rate of 0.5C/0.1C.
The test results of the above values are all shown in table 1.
TABLE 1
From Table 1, the following conclusions can be analytically drawn:
1) From the comparison of examples 1 to 8 and comparative examples 5 to 7, it can be seen that the ratio of the imidazole ionic liquid unit has a significant effect on the lithium ion migration number of the polymer electrolyte, and the larger the ratio of the imidazole ionic liquid unit is, the higher the lithium ion migration number is; the content of the polyethylene glycol chain segment has obvious influence on the ionic conductivity of the polymer electrolyte, the content of the polyethylene glycol chain segment is related to the values of n and m, the smaller the content of the polyethylene glycol chain segment is, the transmission of lithium ions is influenced, the lower the ionic conductivity is, the higher the content of the polyethylene glycol chain segment is, the crystallinity of the polymer electrolyte is easily increased, and the ionic conductivity is reduced, wherein compared with the other embodiments, the embodiment 4 has larger occupation of the compound shown in the formula II, and relatively more imidazole content, so the lithium ion migration number is higher, but compared with the other embodiments, the content of the polyethylene glycol chain segment is lower, the ionic conductivity is lower, and the cycle performance and the multiplying power performance are relatively poorer.
2) As can be seen from comparison of examples 1 and 9-12, when the molar ratio of the polyethylene glycol chain segment to LiTFSI in the compound shown in the formula I-1 and the compound shown in the formula II is in the range of (10-25): 1, the polymer electrolyte has excellent lithium ion migration number and ion conductivity, and the battery has excellent cycle performance and rate performance, however, when the molar ratio of the two is out of the ranges, namely 8:1 and 30:1, respectively, the content of the lithium salt is too much or too little, the lithium salt cannot be dissociated, the number of dissociable lithium ions is small, the content of the lithium salt is too small, the number of lithium ions transferred is small, and the cycle performance and rate performance of the battery are relatively poor.
3) From comparison of examples 1 and 13 to 16, it can be seen that the thickness of the polymer electrolyte has a certain influence on the cycle performance and the rate performance of the battery, and the thickness of the polymer electrolyte can enable the battery to have excellent lithium ion cycle performance and rate performance at the same time within 20 to 50 μm, when the thickness of the polymer electrolyte is lower (15 μm), the transmission path of lithium ions is shorter, and has excellent rate performance, but the battery is easier to short, resulting in poor cycle performance, and when the thickness of the polymer electrolyte is higher (60 μm), the battery is less prone to short, and the cycle performance is better, but the transmission path of lithium ions is longer, resulting in poor rate performance of the battery.
4) From a comparison of examples 1 and 17, it can be seen that the different kinds of lithium salts and R anions can provide the polymer electrolyte with excellent lithium ion migration number and ion conductivity, and the battery with excellent cycle performance and rate performance.
5) From comparison of example 1 and comparative examples 1 and 2, it can be seen that when the polymer obtained by mixing the polymer obtained by using only the compound represented by formula I-1 as a monomer with a lithium salt is a polymer electrolyte, the obtained polymer has no cross-linking, has poor mechanical strength, causes a battery to be easily short-circuited, has poor performances in various aspects of the battery, particularly has poor cycle performance, and when the polymer obtained by using only the compound represented by formula II-1 as a monomer is a polymer electrolyte obtained by mixing the polymer obtained by using a lithium salt, the obtained polymer has an excessively large degree of cross-linking, causes a polymer electrolyte to have excessively high rigidity, has poor compatibility with an interface between positive and negative electrodes, has poor contact, and further causes poor ionic conductivity, cycle performance and rate performance.
6) As can be seen from the comparison of example 1 and comparative example 3, when the compound represented by formula a and the compound represented by formula b are cross-linked and polymerized, microphase separation phenomenon is easy to occur, and further the lithium ion migration number and the ion conductivity of the polymer electrolyte are low, and the cycle performance and the rate performance of the battery are also poor.
7) As can be seen from the comparison of example 1, comparative example 3 and comparative example 4, when the imidazole ionic liquid group is not contained in both of the polymerization monomers of comparative example 4, although the presence of the polyethylene glycol segment can give the electrolyte a higher ionic conductivity, the lithium ion mobility is poor, and accordingly, the cycle performance and the rate performance of the battery are also poor.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. A polymer electrolyte comprising a polymer and a lithium salt, wherein the polymer comprises a crosslinked body obtained by copolymerizing a compound represented by formula I and a compound represented by formula II:
；；
In the formula I, m is an integer selected from 2-20;
In the formula II, R is selected from bis (trifluoromethylsulfonyl) imide, bis (fluorosulfonyl) imide, perchlorate, tetrafluoroborate, dioxaborate, difluoroborate or trifluoromethylsulfonate, and n is selected from integers of 1-10.
2. The polymer electrolyte according to claim 1, wherein the copolymerization molar ratio of the compound represented by formula I and the compound represented by formula II is (70 to 95): (5-30).
3. The polymer electrolyte according to claim 1 or 2, wherein the molar ratio of the sum of polyethylene glycol structural units in the compound represented by the formula I and the compound represented by the formula II to the lithium salt is (10 to 25): 1.
4. The polymer electrolyte of claim 1 wherein the lithium salt comprises one or more of lithium bis (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium difluorooxalato borate, lithium dioxaato borate, lithium perchlorate.
5. A method for producing the polymer electrolyte according to any one of claims 1 to 4, comprising the steps of:
and adding a free radical initiator into a mixed system of the compound shown in the formula I, the compound shown in the formula II and the lithium salt to initiate polymerization reaction, so as to obtain the polymer electrolyte.
6. The preparation method according to claim 5, wherein the compound represented by formula II is prepared by a method comprising the steps of:
1) Reacting 1-vinylimidazole with a compound represented by formula III to obtain a compound represented by formula IV;
，
in the formula III, X is selected from Cl, br or I;
2) Carrying out ion exchange reaction on a compound shown in a formula IV and LiR to obtain a compound shown in a formula II;
。
7. The method according to claim 5, wherein the polymerization reaction is carried out at a temperature of 60 to 100 ℃ for a time of 4 to 12 hours.
8. A battery comprising a positive electrode, a negative electrode, and an electrolyte layer between the positive electrode and the negative electrode, wherein the electrolyte layer comprises the polymer electrolyte of any one of claims 1-4.
9. The battery of claim 8, wherein the electrolyte layer has a thickness of 20-50 μm.
10. An electronic device comprising the battery of claim 9.
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| CN104681862A (en) * | 2013-11-29 | 2015-06-03 | 三星电子株式会社 | Polymer, polymer electrolyte, negative electrode protective layer and lithium battery |
| CN115867383A (en) * | 2020-05-05 | 2023-03-28 | 诺姆斯科技股份有限公司 | Bifunctional ionic liquids for electrolytes |
| CN116315061A (en) * | 2022-09-08 | 2023-06-23 | 常州大学 | Vinyl imidazole polyion liquid-based solid polymer electrolyte membrane for lithium battery and preparation method thereof |
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| CN104681862A (en) * | 2013-11-29 | 2015-06-03 | 三星电子株式会社 | Polymer, polymer electrolyte, negative electrode protective layer and lithium battery |
| CN115867383A (en) * | 2020-05-05 | 2023-03-28 | 诺姆斯科技股份有限公司 | Bifunctional ionic liquids for electrolytes |
| CN116315061A (en) * | 2022-09-08 | 2023-06-23 | 常州大学 | Vinyl imidazole polyion liquid-based solid polymer electrolyte membrane for lithium battery and preparation method thereof |
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