CN114242959A - Alkali metal protective layer, preparation method thereof and application thereof in alkali metal secondary battery - Google Patents
Alkali metal protective layer, preparation method thereof and application thereof in alkali metal secondary battery Download PDFInfo
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- CN114242959A CN114242959A CN202111551626.8A CN202111551626A CN114242959A CN 114242959 A CN114242959 A CN 114242959A CN 202111551626 A CN202111551626 A CN 202111551626A CN 114242959 A CN114242959 A CN 114242959A
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- Prior art keywords
- alkali metal
- protective layer
- lithium metal
- equal
- secondary battery
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- 239000011241 protective layer Substances 0.000 title claims abstract description 102
- 229910052783 alkali metal Inorganic materials 0.000 title claims abstract description 73
- 150000001340 alkali metals Chemical class 0.000 title claims abstract description 73
- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000002002 slurry Substances 0.000 claims abstract description 33
- 239000005033 polyvinylidene chloride Substances 0.000 claims abstract description 21
- 229920001328 Polyvinylidene chloride Polymers 0.000 claims abstract description 20
- 239000011248 coating agent Substances 0.000 claims abstract description 16
- 238000000576 coating method Methods 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims abstract description 13
- 239000007769 metal material Substances 0.000 claims abstract description 12
- 239000003960 organic solvent Substances 0.000 claims abstract description 12
- 239000000654 additive Substances 0.000 claims abstract description 8
- 230000008569 process Effects 0.000 claims abstract description 6
- 230000001681 protective effect Effects 0.000 claims abstract description 6
- 238000003756 stirring Methods 0.000 claims abstract description 6
- 239000012298 atmosphere Substances 0.000 claims abstract description 5
- 238000004519 manufacturing process Methods 0.000 claims abstract description 3
- 229910052744 lithium Inorganic materials 0.000 claims description 168
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 48
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 26
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 26
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 24
- 239000003792 electrolyte Substances 0.000 claims description 22
- -1 polyoxyethylene Polymers 0.000 claims description 19
- 239000004743 Polypropylene Substances 0.000 claims description 17
- 229920001155 polypropylene Polymers 0.000 claims description 16
- 239000012300 argon atmosphere Substances 0.000 claims description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 15
- 239000001301 oxygen Substances 0.000 claims description 15
- 229910052760 oxygen Inorganic materials 0.000 claims description 15
- 229910001290 LiPF6 Inorganic materials 0.000 claims description 14
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims description 10
- 239000002904 solvent Substances 0.000 claims description 9
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 8
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 8
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 7
- 230000000996 additive effect Effects 0.000 claims description 7
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- 239000011734 sodium Substances 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 239000011593 sulfur Substances 0.000 claims description 5
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 claims description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 4
- 229910003684 NixCoyMnz Inorganic materials 0.000 claims description 4
- 239000002033 PVDF binder Substances 0.000 claims description 4
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 4
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 claims description 4
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 4
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 claims description 4
- 229910044991 metal oxide Inorganic materials 0.000 claims description 4
- 150000004706 metal oxides Chemical class 0.000 claims description 4
- 239000002105 nanoparticle Substances 0.000 claims description 4
- 229920000620 organic polymer Polymers 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 4
- 229910021135 KPF6 Inorganic materials 0.000 claims description 3
- 229910000552 LiCF3SO3 Inorganic materials 0.000 claims description 3
- 229910019398 NaPF6 Inorganic materials 0.000 claims description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 3
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 3
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 3
- 229910052700 potassium Inorganic materials 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- 239000004408 titanium dioxide Substances 0.000 claims description 3
- HFZLSTDPRQSZCQ-UHFFFAOYSA-N 1-pyrrolidin-3-ylpyrrolidine Chemical compound C1CCCN1C1CNCC1 HFZLSTDPRQSZCQ-UHFFFAOYSA-N 0.000 claims description 2
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 claims description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 2
- 229910000799 K alloy Inorganic materials 0.000 claims description 2
- 229910000733 Li alloy Inorganic materials 0.000 claims description 2
- 229910003405 Li10GeP2S12 Inorganic materials 0.000 claims description 2
- 229910010848 Li6PS5Cl Inorganic materials 0.000 claims description 2
- 229910002984 Li7La3Zr2O12 Inorganic materials 0.000 claims description 2
- 229910013089 LiBF3 Inorganic materials 0.000 claims description 2
- 229910013188 LiBOB Inorganic materials 0.000 claims description 2
- 229910011297 LiCox Inorganic materials 0.000 claims description 2
- 229910010753 LiFex Inorganic materials 0.000 claims description 2
- 229910013385 LiN(SO2C2F5)2 Inorganic materials 0.000 claims description 2
- 229910013406 LiN(SO2CF3)2 Inorganic materials 0.000 claims description 2
- 229910013405 LiN(SO2CF3)3 Inorganic materials 0.000 claims description 2
- 229910013876 LiPF2 Inorganic materials 0.000 claims description 2
- 229910013884 LiPF3 Inorganic materials 0.000 claims description 2
- 229910012835 LiwNixCoyMnz Inorganic materials 0.000 claims description 2
- 229910000528 Na alloy Inorganic materials 0.000 claims description 2
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 239000000919 ceramic Substances 0.000 claims description 2
- LMEDOLJKVASKTP-UHFFFAOYSA-N dibutyl sulfate Chemical compound CCCCOS(=O)(=O)OCCCC LMEDOLJKVASKTP-UHFFFAOYSA-N 0.000 claims description 2
- SBZXBUIDTXKZTM-UHFFFAOYSA-N diglyme Chemical compound COCCOCCOC SBZXBUIDTXKZTM-UHFFFAOYSA-N 0.000 claims description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052731 fluorine Inorganic materials 0.000 claims description 2
- 239000011737 fluorine Substances 0.000 claims description 2
- 239000003365 glass fiber Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 239000001989 lithium alloy Substances 0.000 claims description 2
- 229910001547 lithium hexafluoroantimonate(V) Inorganic materials 0.000 claims description 2
- 229910001540 lithium hexafluoroarsenate(V) Inorganic materials 0.000 claims description 2
- 229910001486 lithium perchlorate Inorganic materials 0.000 claims description 2
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 claims description 2
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 2
- 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 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- YKYONYBAUNKHLG-UHFFFAOYSA-N n-Propyl acetate Natural products CCCOC(C)=O YKYONYBAUNKHLG-UHFFFAOYSA-N 0.000 claims description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Inorganic materials [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 2
- 229910001487 potassium perchlorate Inorganic materials 0.000 claims description 2
- 229940090181 propyl acetate Drugs 0.000 claims description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 229910052712 strontium Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 229910001928 zirconium oxide Inorganic materials 0.000 claims description 2
- 239000011149 active material Substances 0.000 claims 1
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 12
- 229920000642 polymer Polymers 0.000 abstract description 7
- 210000001787 dendrite Anatomy 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 6
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 239000003570 air Substances 0.000 description 43
- 239000000843 powder Substances 0.000 description 15
- 239000011259 mixed solution Substances 0.000 description 13
- 239000007774 positive electrode material Substances 0.000 description 13
- 229910013872 LiPF Inorganic materials 0.000 description 8
- 101150058243 Lipf gene Proteins 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000004146 energy storage Methods 0.000 description 7
- 239000002932 luster Substances 0.000 description 7
- 230000001351 cycling effect Effects 0.000 description 6
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 5
- 229910001413 alkali metal ion Inorganic materials 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 4
- 239000003513 alkali Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000001878 scanning electron micrograph Methods 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 210000004027 cell Anatomy 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- 239000007773 negative electrode material Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052493 LiFePO4 Inorganic materials 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 2
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910013553 LiNO Inorganic materials 0.000 description 1
- 229910002991 LiNi0.5Co0.2Mn0.3O2 Inorganic materials 0.000 description 1
- 229910015872 LiNi0.8Co0.1Mn0.1O2 Inorganic materials 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000006255 coating slurry Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004299 exfoliation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- RYZCLUQMCYZBJQ-UHFFFAOYSA-H lead(2+);dicarbonate;dihydroxide Chemical compound [OH-].[OH-].[Pb+2].[Pb+2].[Pb+2].[O-]C([O-])=O.[O-]C([O-])=O RYZCLUQMCYZBJQ-UHFFFAOYSA-H 0.000 description 1
- IDBFBDSKYCUNPW-UHFFFAOYSA-N lithium nitride Chemical compound [Li]N([Li])[Li] IDBFBDSKYCUNPW-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920000131 polyvinylidene Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/24—Electrodes for alkaline accumulators
- H01M4/26—Processes of manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/24—Alkaline accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/24—Electrodes for alkaline accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
Abstract
The invention belongs to the field of polymer-based protective layer materials for secondary batteries, and discloses an alkali metal protective layer, a preparation method thereof and application thereof in an alkali metal secondary battery. The preparation method comprises the steps of dissolving or dispersing protective layer components in an organic solvent, stirring to form uniform slurry, coating the slurry on the surface of an alkali metal material in a protective atmosphere, and volatilizing the organic solvent to obtain an alkali metal protective layer; the protective layer comprises polyvinylidene chloride and additives. The invention has simple and convenient process, strong operability, controllable area and thickness of the alkali metal protective layer and easy mass production. The alkali metal protective layer can effectively block air and water, can inhibit the generation of alkali metal dendrites, has good film-forming performance and chemical stability, and is beneficial to solving the problems that active alkali metal cannot be stably stored in air, the transportation cost is high and the like; the alkali metal secondary battery with the alkali metal protective film has excellent electrochemical performance and safety performance.
Description
Technical Field
The invention belongs to the field of polymer-based protective layer materials for secondary batteries, and particularly relates to an alkali metal protective layer, a preparation method thereof and application thereof in an alkali metal secondary battery.
Background
The development of advanced energy storage technology is crucial to meet the requirements of portable electronic products, electric vehicles, stationary grid storage and the like. The alkali metal (lithium, sodium and potassium) ion secondary battery has the advantages of high energy density, long service life, environmental protection, low self-discharge rate and the like, is already applied or is about to be applied to various occasions on a large scale, and is an important energy storage device. The development and application of energy storage materials (including positive electrode materials, negative electrode materials, electrolyte materials, conductive agent materials, binder materials and the like) have a key driving role in the development of energy storage devices. At present, the negative electrode of the alkali metal ion secondary battery is mainly a carbon material such as graphite, soft carbon, hard carbon, and the like. However, the actual energy density of most alkali metal ion secondary batteries using carbon materials as the negative electrode is gradually close to the theoretical limit value, and such alkali metal ion secondary batteries enter the development bottleneck period, and the energy density thereof cannot realize qualitative leap, so that a negative electrode material with higher theoretical capacity is urgently needed to meet the development requirement of emerging advanced energy storage devices.
Alkali metals are ideal anode materials for next generation alkali metal ion secondary batteries due to their high theoretical capacity and low standard electrode potential. Alkali metal ion secondary batteries, namely alkali metal secondary batteries, which take alkali metal as a negative electrode, comprise alkali metal-oxide batteries, alkali metal-sulfur batteries and alkali metal-air batteries, and all of the alkali metal-oxide batteries, the alkali metal-sulfur batteries and the alkali metal-air batteries have high theoretical energy density, and are important development directions in the field of future energy storage. However, the direct use of alkali metals as negative electrode materials still faces a series of problems to be solved: the alkali metal has active chemical property, is very easy to react with air and water, is difficult to be stored in the air for a long time, and is difficult to be stored and transported; the uneven surface shape of the alkali metal leads to uneven surface charge distribution, dendritic crystals are easily generated, the cycle performance of the battery is reduced, and the battery can be punctured through a diaphragm to cause short circuit and cause potential safety hazards. The air and water instability and uncontrolled dendrite growth of alkali metals have severely hampered the commercial application of alkali metal secondary batteries and have not been conducive to the development of the energy storage field. Therefore, the development of the alkali metal cathode which has air and water stability and can inhibit the growth of dendritic crystals can reduce the requirements on the storage and transportation environment of the alkali metal, improve the cycle stability and safety of the alkali metal secondary battery and have great practical value.
Disclosure of Invention
In order to overcome the disadvantages and drawbacks of the prior art, the primary object of the present invention is to provide a method for preparing an alkali metal protective layer; the method takes polyvinylidene chloride with high air and water barrier properties and an additive with high ionic conductivity as protective layer components, the protective layer components are dissolved or dispersed in an organic solvent to prepare slurry and then are coated on the surface of an alkali metal material, and the alkali metal protective layer can be obtained after the organic solvent is removed.
The invention also aims to provide an alkali metal protective layer prepared by the preparation method; the protective layer can prevent air and moisture from contacting the alkali metal, inhibit the formation of alkali metal dendrite and prolong the cycle life of the alkali metal secondary battery.
It is a further object of the present invention to provide use of the above alkali metal protective layer in an alkali metal secondary battery; the alkali metal secondary battery has the alkali metal negative electrode protective layer and has excellent electrochemical performance.
The purpose of the invention is realized by the following technical scheme:
a method for preparing an alkali metal protective layer comprises the following steps:
(1) dissolving or dispersing the dried protective layer components in an organic solvent, and fully stirring to form uniform slurry; the protective layer comprises polyvinylidene chloride (PVDC) and an additive, wherein the additive accounts for 0-50 wt%;
(2) and (3) coating the slurry obtained in the step (1) on the surface of an alkali metal material in a protective atmosphere, and volatilizing an organic solvent to obtain an alkali metal protective layer on the surface of the alkali metal material.
Preferably, the additive in the step (1) is one or more of organic polymer and inorganic nano particles; the organic polymer is polyethylene oxide (PEO), Polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), and poly (vinylidene fluoride-co-hexa-ethylene)Fluoropropylene) (PVDF-HFP) or Polymethylmethacrylate (PMMA); the inorganic nano-particles are silicon dioxide, zirconium oxide, titanium dioxide and Li7La3Zr2O12、Li6.4La3Zr1.4Ta0.6O12、Li10GeP2S12Or Li6PS5Cl。
Preferably, the organic solvent in step (1) is one or more of tetrahydrofuran, N-methylpyrrolidone, cyclohexanone and N, N-dimethylformamide; the alkali metal material in the step (2) is commercial lithium sheet, sodium sheet, potassium sheet, lithium alloy, sodium alloy or potassium alloy.
Preferably, the fully-stirred process conditions in the step (1) are as follows: magnetically stirring at 20-30 deg.C for 2-24 hr;
preferably, the protective atmosphere in the step (2) is an argon atmosphere with both a water value and an oxygen value less than or equal to 0.1 ppm;
preferably, the process conditions for volatilizing the organic solvent in the step (2) are as follows: under the argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, the temperature is maintained at 20-70 ℃, and the natural volatilization is carried out for 12-72 h.
Preferably, the content of the protective layer component in the slurry in the step (1) is 0.1-30 wt%; the coating amount of the slurry in the step (2) coated on the surface of the alkali metal material is 5-100 mu L cm-2。
An alkali metal protective layer prepared by the above preparation method.
The alkali metal secondary battery comprises a positive electrode, a diaphragm, electrolyte and a negative electrode, wherein the negative electrode is an alkali metal material with the surface provided with the alkali metal protective layer.
The active substance of the positive electrode is air, sulfur or composite metal oxide; the composite metal oxide is LiwNixCoyMnzA(1-x-y-z)O2、LiCoxA(1-x)O2、LiFexA(1-x)PO4、NawNixCoyMnzA(1-x-y-z)O2、NaCoxA(1-x)O2、NaFexA(1-x)PO4、KwNixCoyMnzA(1-x-y-z)O2、KCoxA(1-x)O2And KFexA(1-x)PO4Wherein A is Al, Sr, Mg, Ti, Ca, Zr, Zn, Si or Fe, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and w is more than or equal to 0 and less than or equal to 2.
Preferably, the separator is one of a polypropylene film, a polyethylene film, a polypropylene/polyethylene/polypropylene film, a polytetrafluoroethylene separator, a ceramic porous film, and a glass fiber separator.
Preferably, the electrolyte has a concentration of 0.5-10M, and comprises a solvent and an electrolyte salt dissolved in the solvent; the solvent is one or more of dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, acrylonitrile, dimethyl sulfoxide, trimethylolpropane, ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, a fluorine-containing solvent, ethyl acetate, propyl acetate, ethylene glycol dimethyl ether, tetrahydrofuran, butyl acrylate, dibutyl sulfate, ethyl propionate, propyl propionate and butyl propionate; the electrolyte salt is LiF or LiNO3、LiPF2、LiPF6、LiClO4、LiBF4、LiBOB、LiDFOB、LiAsF6、LiSbF6、LiCF3SO3、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiN(SO2CF3)3、LiPF3(C3F7)3、LiB(CF3)4、LiBF3(C2F5)、NaPF6、NaF、NaNO3、NaFSi、NaNO3、KClO4、KPF6KFSi, KF and KNO3One or more of them.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the alkali metal protective layer provided by the invention has good film forming property and chemical stability, can effectively block air and water, enables the alkali metal with the alkali metal protective layer to have excellent air stability and water stability, and is beneficial to solving the problems that the active alkali metal cannot be stably stored in the air and the transportation cost is high.
(2) The alkali metal protective layer provided by the invention can inhibit the growth of alkali metal dendrites and improve the cycle stability of the alkali metal secondary battery with the alkali metal protective layer.
(3) The alkali metal protective layer provided by the invention can be prepared by coating slurry and volatilizing a solvent, and the area and the thickness of the alkali metal protective layer are easy to control.
(4) The preparation method of the alkali metal protective layer provided by the invention is simple and convenient, the raw material source is cheap, and the mass production is easy.
Drawings
FIG. 1 is a scanning electron micrograph and a digital micrograph (upper right inset) of the film before and after exposure to air in example 1, wherein the left side is before exposure to air and the right side is after exposure to air.
FIG. 2 is a scanning electron micrograph and a digital micrograph (upper right inset) of comparative example 1 before and after exposure to air, wherein the left side is before exposure to air and the right side is after exposure to air.
FIG. 3 is a digital photograph showing the change of surface morphology with time after exposure of example 1, example 2 and comparative example 1 to air.
FIG. 4 is an X-ray diffraction pattern of example 1 and comparative example 1 after exposure to air.
FIG. 5 is a digital photograph of comparative example 1 before and after water was dropped on the surface.
FIG. 6 is a digital photograph of the surface of example 3 before and after dropping water.
Fig. 7 is a graph of the cycling performance of the symmetric cells of example 1 and comparative example 1.
Fig. 8 is a charge and discharge graph of the full cell of example 1 and comparative example 1.
Fig. 9 is a graph of cycle performance of the full cells of example 1 and comparative example 1.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.
Example 1
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.05g of the dried PVDC powder was weighed out and dissolved in 9.95g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a PVDC content of 0.5 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
The scanning electron microscope photograph of the lithium metal protective layer obtained in this example is shown on the left side of fig. 1, and it can be seen from the figure that the lithium metal protective layer is a polymer layer uniformly coated on the surface of the lithium metal, and can play a role in blocking substances, such as air, water, etc., which have corrosiveness and reactivity to the lithium metal. The left upper right inset in fig. 1 is a digital photo of the lithium metal with the lithium metal protective layer obtained in this example, and it can be seen from the photo that the lithium metal maintains the original metallic luster and does not change the color or form, which indicates that the lithium metal protective layer is a colorless and transparent film and does not change the original characteristics of the lithium metal. As shown in fig. 3, when the lithium metal with the lithium metal protective layer obtained in this example is exposed to air at a temperature of 28 ℃ and a relative humidity of 40%, the surface of the lithium metal still has a distinct metallic luster after 10 minutes. The right side of fig. 1 is a scanning electron micrograph of the lithium metal with the lithium metal protective layer obtained in this example after contacting with air for 5min, and it can be seen from the micrograph that the lithium metal surface is still a uniform polymer layer, and no inorganic crystal particles appear; the right upper right inset of fig. 1 is a digital photo of the lithium metal with the lithium metal protection layer obtained in this example after contacting with air for 5min, which shows that the lithium metal surface of the lithium metal protection layer still has obvious metallic luster. The X-ray diffraction pattern of lithium metal with a lithium metal protective layer after 5min contact with air of fig. 4 shows that lithium metal with this lithium metal protective layer has only the diffraction peak of Li and no diffraction peak of LiOH after contact with air. These results demonstrate that the lithium metal protective layer of the present invention has excellent protection effect on lithium metal, and can be stably placed in air environment with high relative humidity without being corroded by air and water.
Two pieces of lithium metal with the lithium metal protective layer obtained in the embodiment are assembled into a symmetrical battery, the diaphragm is PP, and the electrolyte is LiPF6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF6Is 1M. The performance of the battery is tested by using a BTS 7.6.x battery test system produced by Shenzhen New Power company in China, and the test condition is that the charge and discharge current is 1mA cm-2And charge-discharge capacity of 1mAh cm-2. As can be seen from fig. 7, the lithium metal with the lithium metal protective layer obtained in this embodiment can be stably cycled for 300h at a low deposition/exfoliation overpotential, which indicates that the lithium metal protective layer has a good lithium ion transport capability, and can effectively inhibit the formation of lithium dendrites during cycling, and the lithium metal with the lithium metal protective layer has a good cycling performance.
With a ternary material LiNi0.5Co0.2Mn0.3O2(NCM523) as a positive electrode active material, and a positive electrode, a polypropylene separator and an electrolyte (LiPF) were formed using the lithium metal having the lithium metal protective layer obtained in this example as a negative electrode6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery. The performance of the battery is tested by using a BTS 7.6.x battery test system produced by Shenzhen New Power company in China under the condition that the current density is 0.152mA cm-2And the voltage range is 3-4.3V. Fig. 8 shows that such a lithium metal secondary battery has a normal charge and discharge curve, illustrating that the lithium metal protective layer does not affect the intercalation/deintercalation of lithium ions during the charge and discharge of the lithium metal secondary battery. As shown in the results of FIG. 9, it was confirmed that the first turn of the lithium metal secondary battery having the lithium metal protective layer can obtain 2.07mAh cm-2High specific discharge capacity of (2); after 100 cycles, the lithium metal secondary battery has a specific discharge capacity of1.86mAh cm -290% of the first-ring specific discharge capacity is reserved; the specific discharge capacity of the lithium metal secondary battery is still 1.66mAh cm even after 165 times of circulation-2And 80% of the first-circle discharge specific capacity is reserved. This fully demonstrates that the lithium metal secondary battery with the lithium metal protective layer can obtain higher specific capacity in the actual charging and discharging process and has good cycling stability.
Comparative example 1
A scanning electron micrograph of the lithium metal sheet is shown on the left side of FIG. 2, and it can be seen from the figure that the surface of the lithium metal sheet is relatively flat. The left upper right inset in fig. 2 is a digital photo with the lithium metal sheet, and it can be seen from the photo that the lithium metal sheet is silvery white and has a relatively obvious metallic luster. As shown in fig. 3, when the lithium metal sheet is exposed to air at a temperature of 28 ℃ and a relative humidity of 40%, the surface of the lithium metal becomes black after 2 minutes, and the original metallic luster is lost, and the black level of the lithium metal sheet is gradually increased instead of being restored as time goes by, which means that the lithium metal sheet rapidly reacts with air and moisture continuously and irreversibly to produce a substance capable of blackening the surface of the lithium metal sheet, and the substance is probably lithium nitride generated by the reaction of the lithium metal and nitrogen in the humid air. Fig. 2 is a scanning electron microscope photograph of the lithium metal sheet after contacting air for 5min, from which it can be seen that the surface of the lithium metal sheet has lost the original flat state and a large amount of crystal particles appear, so that the surface of the lithium metal sheet becomes uneven, loose and porous; the right upper right inset of fig. 2 is a digital photograph of the lithium metal sheet after 5min contact with air, which shows that the surface of the lithium metal sheet has completely blackened and lost the original metallic luster. The X-ray diffraction pattern of the lithium metal sheet after 5min contact with air in fig. 4 shows that the lithium metal sheet after contact with air shows LiOH diffraction peaks in addition to Li diffraction peaks, indicating that the lithium metal sheet reacts with water. These results indicate that the lithium metal sheet cannot be stably placed in an air environment, and is very susceptible to deterioration caused by air and water.
Further, 10 μ L of deionized water was dropped on the surface of the lithium metal plate, and it was observed that at the moment when the water drop contacted the lithium metal plate, the two reacted violently, releasing a large amount of gas, and fig. 5 is a digital photograph of the surface of the lithium metal plate before and after dropping water, which shows that the surface morphology of the lithium metal plate changed greatly after dropping water, and the color changed from silver white to black or white, which indicates that the lithium metal plate became rather unstable after encountering water.
Two metal lithium sheets are assembled into a symmetrical battery, a diaphragm is polypropylene, and electrolyte is LiPF6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF6Is 1M. The performance of the battery is tested by using a BTS 7.6.x battery test system produced by Shenzhen New Power company in China, and the test condition is that the charge and discharge current is 1mA cm-2And charge-discharge capacity of 1mAh cm-2. As can be seen from fig. 7, the lithium metal sheet can only be stably cycled for about 150h, which is much lower than the lithium metal having a lithium metal protective layer, indicating that the lithium metal sheet cannot avoid the formation of lithium dendrites during cycling, and thus the lithium metal sheet shows poor cycling performance.
Taking the ternary material NCM523 as a positive electrode active material and the metal lithium sheet as a negative electrode, and taking the positive electrode, a polypropylene diaphragm and an electrolyte (LiPF)6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery. The performance of the battery is tested by using a BTS 7.6.x battery test system produced by Shenzhen New Power company in China under the condition that the current density is 0.152mA cm-2And the voltage range is 3-4.3V. As shown in FIG. 9, the specific discharge capacity of the first ring of the lithium metal secondary battery is 1.14mAh cm-2Lower than lithium metal secondary batteries having a lithium metal protective layer; after 100 times of circulation, the specific discharge capacity of the lithium metal secondary battery is 0.96mAh cm-284% of the first-turn specific discharge capacity is reserved; after 112 cycles, the specific discharge capacity of the lithium metal secondary battery is suddenly reduced to 0.45mAh cm-2Only 39% of the first-turn specific discharge capacity is reserved. This indicates that the lithium metal secondary battery has poor cycle stability during actual charge and discharge.
Example 2
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.50g of the dried PVDC powder was weighed out and dissolved in 9.50g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a PVDC content of 5.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
The lithium metal having the lithium metal protective layer obtained in this example was exposed to air at a temperature of 28 ℃ and a relative humidity of 40%, and tested for air stability. As shown in fig. 3, the lithium metal surface still has a distinct metallic luster after 20 minutes, and there is no change in other colors or forms, which indicates that the lithium metal protective layer has a good barrier effect on air, and the lithium metal with the lithium metal protective layer can be stably placed in an air environment with a high relative humidity.
With LiFePO4As a positive electrode active material, a positive electrode, a polypropylene separator, and an electrolyte (LiPF) were prepared using the lithium metal having a lithium metal protective layer obtained in this example as a negative electrode6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 3
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.80g of the dried PVDC powder was weighed out and dissolved in 9.20g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a PVDC content of 8.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
When 10 μ L of deionized water was dropped on the surface of the lithium metal having the lithium metal protective layer obtained in this example, it was observed that no reaction occurred when the water droplets were in contact with the lithium metal having the lithium metal protective layer, and only they were agglomerated on the lithium metal protective layer. Fig. 6 is a digital photograph of the lithium metal surface having the lithium metal protective layer before and after dropping water, and the photograph shows that the lithium metal surface having the lithium metal protective layer has no change in morphology after dropping water, which shows that the lithium metal protective layer has excellent water-proof property and can better prevent water from reacting with lithium metal.
With LiFePO4As a positive electrode active material, a positive electrode, a polypropylene separator, and an electrolyte (LiPF) were prepared using the lithium metal having a lithium metal protective layer obtained in this example as a negative electrode6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 4
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.05g of dried PVDC powder was weighed out and dissolved in 9.95g N-methylpyrrolidone, and stirred at 25 ℃ for 12 hours to form a slurry with a PVDC content of 0.5 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, volatilizing N-methylpyrrolidone at 60 ℃ for 36 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
The ternary material NCM523 was used as a positive electrode active material, the lithium metal having a lithium metal protective layer obtained in this example was used as a negative electrode, and a positive electrode, a polypropylene separator, and an electrolyte (LiPF) were used6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein carbon is containedThe volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 5
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.90g of dried PVDC powder and 0.10g of dried PEO powder (Mw 600,000) were weighed out and dissolved in 9.00g of tetrahydrofuran, and the mixture was stirred at 25 ℃ for 12 hours to form a slurry having a polymer content of 10.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, at a concentration of 30 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
The ternary material NCM523 was used as a positive electrode active material, the lithium metal having a lithium metal protective layer obtained in this example was used as a negative electrode, and a positive electrode, a polypropylene separator, and an electrolyte (LiPF) were used6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 6
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.90g of dried PVDC powder and 0.10g of dried PVDF powder were weighed out and dissolved in 9.00g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a polymer content of 10.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, at a concentration of 30 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
With a ternary material LiNi0.8Co0.1Mn0.1O2(NCM811) as a positive electrode active material, a negative electrode made of lithium metal having a lithium metal protective layer according to the European expression of this example, and a positive electrode and polypropyleneSeparator and electrolyte (LiPF)6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 7
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.90g of dried PVDC powder and 0.10g of dried PVDF-HFP particles were weighed out and dissolved in 9.00g of tetrahydrofuran and stirred at 25 ℃ for 24 hours to form a slurry with a polymer content of 10.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, at a concentration of 30 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
The positive electrode, the polypropylene separator, and the electrolyte (LiPF) were prepared by using the ternary material NCM811 as the positive electrode active material and the lithium metal having the lithium metal protective layer obtained in this example as the negative electrode6Dissolved in a mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of the ethylene carbonate to the dimethyl carbonate is 1:1, and LiPF61M) and a negative electrode to obtain a lithium metal secondary battery.
Example 8
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.85g of dried PVDC powder and 0.15g of dried Li were weighed7La3Zr2O12The powder was dissolved or dispersed in 8.00g of tetrahydrofuran, and stirred at 25 ℃ for 48 hours to form a slurry having a protective layer component content of 20.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm at a concentration of 20 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
Sulfur is used as positive active material, and the product is prepared byThe lithium metal having the lithium metal protective layer obtained in example was used as a negative electrode, and a positive electrode, a polypropylene separator, and an electrolyte (LiN (SO)2CF3)2Dissolving in mixed solution of 1, 3-dioxolane and ethylene glycol dimethyl ether at a volume ratio of 1:1, LiN (SO)2CF3)21M, 1% LiNO was added3) And assembling the lithium metal secondary battery with the negative electrode to obtain the lithium metal secondary battery.
Example 9
A preparation method of a lithium metal protective layer comprises the following steps:
(1) 0.85g of the dried PVDC powder and 0.15g of the dried titanium dioxide powder were weighed, dissolved or dispersed in 8.00g of tetrahydrofuran, and stirred at 25 ℃ for 48 hours to form a slurry having a protective layer component content of 20.0 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm at a concentration of 20 μ L cm-2Coating the slurry in the step (1) on the surface of a lithium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
Using air as a positive electrode active material and lithium metal having a lithium metal protective layer obtained in this example as a negative electrode, a positive electrode (Pt), a polypropylene separator, and an electrolyte (LiCF) were placed3SO3Dissolved in tetraethylene glycol dimethyl ether to obtain LiCF3SO31M) and negative electrode assembly, and introducing air to obtain a lithium metal secondary battery.
Example 10
A preparation method of a sodium metal protective layer comprises the following steps:
(1) 0.05g of the dried PVDC powder was weighed out and dissolved in 9.95g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a PVDC content of 0.5 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a metal sodium sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a sodium metal protective layer on the surface of the metal sodium sheet.
With ternary material NaNi0.8Co0.1Mn0.1O2As a positive electrode active material, a positive electrode, a glass cellulose separator, and an electrolyte (NaPF) were prepared using sodium metal having a sodium metal protective layer obtained in this example as a negative electrode6Dissolving in mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1, and NaPF61M) and a negative electrode to obtain a sodium metal secondary battery.
Example 11
A preparation method of a potassium metal protective layer comprises the following steps:
(1) 0.05g of the dried PVDC powder was weighed out and dissolved in 9.95g of tetrahydrofuran, and stirred at 25 ℃ for 12 hours to form a slurry having a PVDC content of 0.5 wt%.
(2) In an argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, in a concentration of 15 μ L cm-2Coating the slurry in the step (1) on the surface of a potassium metal sheet, and volatilizing tetrahydrofuran at 25 ℃ for 48 hours to obtain a lithium metal protective layer on the surface of the lithium metal sheet.
With ternary material K0.67Ni0.17Co0.17Mn0.66O2As a positive electrode active material, a positive electrode, a glass cellulose separator, and an electrolyte (KPF) were prepared by using potassium metal having a potassium metal protective layer obtained in this example as a negative electrode6Dissolving in mixed solution of ethylene carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1, KPF60.8M) and the negative electrode were assembled to obtain a potassium metal secondary battery.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (10)
1. A preparation method of an alkali metal protective layer is characterized by comprising the following steps:
(1) dissolving or dispersing the dried protective layer components in an organic solvent, and fully stirring to form uniform slurry; the protective layer comprises polyvinylidene chloride and an additive, wherein the content of the additive is 0-50 wt%;
(2) and (3) coating the slurry obtained in the step (1) on the surface of an alkali metal material in a protective atmosphere, and volatilizing an organic solvent to obtain an alkali metal protective layer on the surface of the alkali metal material.
2. The method of claim 1, wherein: the additive in the step (1) is one or more of organic polymer and inorganic nano particles; the organic polymer is polyoxyethylene, polyacrylonitrile, polyvinylidene fluoride, poly (vinylidene fluoride-co-hexafluoropropylene) or polymethyl methacrylate; the inorganic nano-particles are silicon dioxide, zirconium oxide, titanium dioxide and Li7La3Zr2O12、Li6.4La3Zr1.4Ta0.6O12、Li10GeP2S12Or Li6PS5Cl。
3. The method of claim 1, wherein: the organic solvent in the step (1) is one or more of tetrahydrofuran, N-methyl pyrrolidone, cyclohexanone and N, N-dimethylformamide; the alkali metal material in the step (2) is commercial lithium sheet, sodium sheet, potassium sheet, lithium alloy, sodium alloy or potassium alloy.
4. The method of claim 1, wherein: the process conditions of the step (1) of fully stirring are as follows: magnetically stirring at 20-30 deg.C for 2-24 hr;
the protective atmosphere in the step (2) is specifically argon atmosphere with both water value and oxygen value less than or equal to 0.1 ppm;
the process conditions for volatilizing the organic solvent are as follows: under the argon atmosphere with water value and oxygen value less than or equal to 0.1ppm, the temperature is maintained at 20-70 ℃, and the natural volatilization is carried out for 12-72 h.
5. The method of claim 1, wherein: the content of the protective layer in the slurry in the step (1) is 0.1-30 wt%; the coating amount of the slurry in the step (2) coated on the surface of the alkali metal material is 5-100 mu L cm-2。
6. An alkali metal protective layer produced by the production method according to any one of claims 1 to 5.
7. An alkali metal secondary battery characterized in that: the battery comprises a positive electrode, a diaphragm, an electrolyte and a negative electrode, wherein the negative electrode is an alkali metal material with the surface provided with the alkali metal protective layer of claim 6.
8. The alkali metal secondary battery according to claim 7, wherein the active material of the positive electrode is air, sulfur, or a composite metal oxide; the composite metal oxide is LiwNixCoyMnzA(1-x-y-z)O2、LiCoxA(1-x)O2、LiFexA(1-x)PO4、NawNixCoyMnzA(1-x-y-z)O2、NaCoxA(1-x)O2、NaFexA(1-x)PO4、KwNixCoyMnzA(1-x-y-z)O2、KCoxA(1-x)O2And KFexA(1-x)PO4Wherein A is Al, Sr, Mg, Ti, Ca, Zr, Zn, Si or Fe, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and w is more than or equal to 0 and less than or equal to 2.
9. The alkali metal secondary battery according to claim 7, characterized in that: the diaphragm is one of a polypropylene film, a polyethylene film, a polypropylene/polyethylene/polypropylene film, a polytetrafluoroethylene diaphragm, a ceramic porous film and a glass fiber diaphragm.
10. The alkali metal secondary battery according to claim 7, characterized in that: the electrolyte has a concentration of 0.5-10M, and comprises a solvent and electrolyte salt dissolved in the solvent; the solvent is one or more of dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, acrylonitrile, dimethyl sulfoxide, trimethylolpropane, ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, a fluorine-containing solvent, ethyl acetate, propyl acetate, ethylene glycol dimethyl ether, tetrahydrofuran, butyl acrylate, dibutyl sulfate, ethyl propionate, propyl propionate and butyl propionate; the electrolyte salt is LiF or LiNO3、LiPF2、LiPF6、LiClO4、LiBF4、LiBOB、LiDFOB、LiAsF6、LiSbF6、LiCF3SO3、LiN(SO2CF3)2、LiN(SO2C2F5)2、LiN(SO2CF3)3、LiPF3(C3F7)3、LiB(CF3)4、LiBF3(C2F5)、NaPF6、NaF、NaNO3、NaFSi、NaNO3、KClO4、KPF6KFSi, KF and KNO3One or more of them.
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