CN117038942A - Hard carbon/silicon composite anode material and preparation method and application thereof - Google Patents
Hard carbon/silicon composite anode material and preparation method and application thereof Download PDFInfo
- Publication number
- CN117038942A CN117038942A CN202311297483.1A CN202311297483A CN117038942A CN 117038942 A CN117038942 A CN 117038942A CN 202311297483 A CN202311297483 A CN 202311297483A CN 117038942 A CN117038942 A CN 117038942A
- Authority
- CN
- China
- Prior art keywords
- hard carbon
- bacterial cellulose
- silicon
- anode material
- composite anode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910021385 hard carbon Inorganic materials 0.000 title claims abstract description 215
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 123
- 239000010703 silicon Substances 0.000 title claims abstract description 123
- 239000002131 composite material Substances 0.000 title claims abstract description 107
- 239000010405 anode material Substances 0.000 title claims abstract description 100
- 238000002360 preparation method Methods 0.000 title claims abstract description 37
- 229920002749 Bacterial cellulose Polymers 0.000 claims abstract description 132
- 239000005016 bacterial cellulose Substances 0.000 claims abstract description 132
- 239000012686 silicon precursor Substances 0.000 claims abstract description 71
- 239000002245 particle Substances 0.000 claims abstract description 51
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 41
- 150000001875 compounds Chemical class 0.000 claims abstract description 41
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 39
- 239000010410 layer Substances 0.000 claims abstract description 38
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 27
- 239000005922 Phosphane Substances 0.000 claims abstract description 25
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910000064 phosphane Inorganic materials 0.000 claims abstract description 25
- 230000008021 deposition Effects 0.000 claims abstract description 21
- 229920000642 polymer Polymers 0.000 claims abstract description 21
- 239000011241 protective layer Substances 0.000 claims abstract description 20
- 239000011148 porous material Substances 0.000 claims abstract description 15
- 229910021417 amorphous silicon Inorganic materials 0.000 claims abstract description 4
- 239000011258 core-shell material Substances 0.000 claims abstract description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 118
- 238000010438 heat treatment Methods 0.000 claims description 45
- GKTNLYAAZKKMTQ-UHFFFAOYSA-N n-[bis(dimethylamino)phosphinimyl]-n-methylmethanamine Chemical compound CN(C)P(=N)(N(C)C)N(C)C GKTNLYAAZKKMTQ-UHFFFAOYSA-N 0.000 claims description 43
- 239000007788 liquid Substances 0.000 claims description 35
- 238000002156 mixing Methods 0.000 claims description 35
- 239000000203 mixture Substances 0.000 claims description 34
- 239000011261 inert gas Substances 0.000 claims description 33
- 238000003756 stirring Methods 0.000 claims description 33
- 238000010000 carbonizing Methods 0.000 claims description 28
- 238000000151 deposition Methods 0.000 claims description 27
- 239000006185 dispersion Substances 0.000 claims description 22
- -1 polyoxyethylene Polymers 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 20
- 239000010426 asphalt Substances 0.000 claims description 17
- 239000007773 negative electrode material Substances 0.000 claims description 13
- 150000003606 tin compounds Chemical class 0.000 claims description 13
- 239000007810 chemical reaction solvent Substances 0.000 claims description 10
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 9
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 claims description 9
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 9
- 229920001568 phenolic resin Polymers 0.000 claims description 9
- 239000005011 phenolic resin Substances 0.000 claims description 9
- 229910002651 NO3 Inorganic materials 0.000 claims description 8
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 8
- 239000003822 epoxy resin Substances 0.000 claims description 8
- 229920000647 polyepoxide Polymers 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 239000007790 solid phase Substances 0.000 claims description 6
- RCIVOBGSMSSVTR-UHFFFAOYSA-L stannous sulfate Chemical compound [SnH2+2].[O-]S([O-])(=O)=O RCIVOBGSMSSVTR-UHFFFAOYSA-L 0.000 claims description 6
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 6
- 229910000375 tin(II) sulfate Inorganic materials 0.000 claims description 6
- 239000004698 Polyethylene Substances 0.000 claims description 5
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 5
- 239000003960 organic solvent Substances 0.000 claims description 5
- 229920000573 polyethylene Polymers 0.000 claims description 5
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 5
- 238000003763 carbonization Methods 0.000 claims description 4
- TXUICONDJPYNPY-UHFFFAOYSA-N (1,10,13-trimethyl-3-oxo-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl) heptanoate Chemical compound C1CC2CC(=O)C=C(C)C2(C)C2C1C1CCC(OC(=O)CCCCCC)C1(C)CC2 TXUICONDJPYNPY-UHFFFAOYSA-N 0.000 claims description 3
- OQBLGYCUQGDOOR-UHFFFAOYSA-L 1,3,2$l^{2}-dioxastannolane-4,5-dione Chemical compound O=C1O[Sn]OC1=O OQBLGYCUQGDOOR-UHFFFAOYSA-L 0.000 claims description 3
- VILCJCGEZXAXTO-UHFFFAOYSA-N 2,2,2-tetramine Chemical compound NCCNCCNCCN VILCJCGEZXAXTO-UHFFFAOYSA-N 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 3
- 229910021626 Tin(II) chloride Inorganic materials 0.000 claims description 3
- 229920001807 Urea-formaldehyde Polymers 0.000 claims description 3
- GZCGUPFRVQAUEE-SLPGGIOYSA-N aldehydo-D-glucose Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C=O GZCGUPFRVQAUEE-SLPGGIOYSA-N 0.000 claims description 3
- HNQGTZYKXIXXST-UHFFFAOYSA-N calcium;dioxido(oxo)tin Chemical compound [Ca+2].[O-][Sn]([O-])=O HNQGTZYKXIXXST-UHFFFAOYSA-N 0.000 claims description 3
- AYOHIQLKSOJJQH-UHFFFAOYSA-N dibutyltin Chemical compound CCCC[Sn]CCCC AYOHIQLKSOJJQH-UHFFFAOYSA-N 0.000 claims description 3
- PWEVMPIIOJUPRI-UHFFFAOYSA-N dimethyltin Chemical compound C[Sn]C PWEVMPIIOJUPRI-UHFFFAOYSA-N 0.000 claims description 3
- TVQLLNFANZSCGY-UHFFFAOYSA-N disodium;dioxido(oxo)tin Chemical compound [Na+].[Na+].[O-][Sn]([O-])=O TVQLLNFANZSCGY-UHFFFAOYSA-N 0.000 claims description 3
- 229920005546 furfural resin Polymers 0.000 claims description 3
- 229920000768 polyamine Polymers 0.000 claims description 3
- 230000035484 reaction time Effects 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 229940079864 sodium stannate Drugs 0.000 claims description 3
- 239000001119 stannous chloride Substances 0.000 claims description 3
- 235000011150 stannous chloride Nutrition 0.000 claims description 3
- FAGUFWYHJQFNRV-UHFFFAOYSA-N tetraethylenepentamine Chemical compound NCCNCCNCCNCCN FAGUFWYHJQFNRV-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 17
- 229910052744 lithium Inorganic materials 0.000 abstract description 17
- 238000001556 precipitation Methods 0.000 abstract description 11
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 60
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 52
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 29
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 28
- 229910052786 argon Inorganic materials 0.000 description 26
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 21
- 239000011294 coal tar pitch Substances 0.000 description 20
- 238000001816 cooling Methods 0.000 description 20
- KDKYADYSIPSCCQ-UHFFFAOYSA-N but-1-yne Chemical compound CCC#C KDKYADYSIPSCCQ-UHFFFAOYSA-N 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 18
- 239000002244 precipitate Substances 0.000 description 18
- 239000007789 gas Substances 0.000 description 15
- 229910000077 silane Inorganic materials 0.000 description 15
- 238000000498 ball milling Methods 0.000 description 14
- 238000007873 sieving Methods 0.000 description 14
- 239000000243 solution Substances 0.000 description 13
- 239000003513 alkali Substances 0.000 description 10
- 229910002804 graphite Inorganic materials 0.000 description 10
- 239000010439 graphite Substances 0.000 description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 9
- 230000001276 controlling effect Effects 0.000 description 9
- 239000011889 copper foil Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 239000011248 coating agent Substances 0.000 description 8
- 238000000576 coating method Methods 0.000 description 8
- 230000003647 oxidation Effects 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 7
- 229910001416 lithium ion Inorganic materials 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- 239000011300 coal pitch Substances 0.000 description 6
- 239000008098 formaldehyde solution Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000000967 suction filtration Methods 0.000 description 6
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 5
- 238000007600 charging Methods 0.000 description 5
- 239000004020 conductor Substances 0.000 description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 238000010277 constant-current charging Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000001307 helium Substances 0.000 description 3
- 229910052734 helium Inorganic materials 0.000 description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 3
- 229910052754 neon Inorganic materials 0.000 description 3
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 229910052704 radon Inorganic materials 0.000 description 3
- SYUHGPGVQRZVTB-UHFFFAOYSA-N radon atom Chemical compound [Rn] SYUHGPGVQRZVTB-UHFFFAOYSA-N 0.000 description 3
- 229910052724 xenon Inorganic materials 0.000 description 3
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 229920002125 Sokalan® Polymers 0.000 description 2
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 2
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 2
- 239000006256 anode slurry Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 238000010280 constant potential charging Methods 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- MWWATHDPGQKSAR-UHFFFAOYSA-N propyne Chemical compound CC#C MWWATHDPGQKSAR-UHFFFAOYSA-N 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000005060 rubber Substances 0.000 description 2
- 239000011856 silicon-based particle Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910021384 soft carbon Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 description 1
- FHVDTGUDJYJELY-UHFFFAOYSA-N 6-{[2-carboxy-4,5-dihydroxy-6-(phosphanyloxy)oxan-3-yl]oxy}-4,5-dihydroxy-3-phosphanyloxane-2-carboxylic acid Chemical compound O1C(C(O)=O)C(P)C(O)C(O)C1OC1C(C(O)=O)OC(OP)C(O)C1O FHVDTGUDJYJELY-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229910013716 LiNi Inorganic materials 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 241000519995 Stachys sylvatica Species 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 229940072056 alginate Drugs 0.000 description 1
- 235000010443 alginic acid Nutrition 0.000 description 1
- 229920000615 alginic acid Polymers 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 229940077388 benzenesulfonate Drugs 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- PZPGRFITIJYNEJ-UHFFFAOYSA-N disilane Chemical compound [SiH3][SiH3] PZPGRFITIJYNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000000840 electrochemical analysis Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- JVZGJLAPJLXQKT-UHFFFAOYSA-N lithium iron(2+) manganese(2+) nickel(2+) oxygen(2-) Chemical compound [O-2].[Fe+2].[Mn+2].[Li+].[Ni+2] JVZGJLAPJLXQKT-UHFFFAOYSA-N 0.000 description 1
- FRMOHNDAXZZWQI-UHFFFAOYSA-N lithium manganese(2+) nickel(2+) oxygen(2-) Chemical compound [O-2].[Mn+2].[Ni+2].[Li+] FRMOHNDAXZZWQI-UHFFFAOYSA-N 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000002070 nanowire Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- RXCVUXLCNLVYIA-UHFFFAOYSA-N orthocarbonic acid Chemical compound OC(O)(O)O RXCVUXLCNLVYIA-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 229920000110 poly(aryl ether sulfone) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000000661 sodium alginate Substances 0.000 description 1
- 235000010413 sodium alginate Nutrition 0.000 description 1
- 229940005550 sodium alginate Drugs 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 229910001948 sodium oxide Inorganic materials 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- VEDJZFSRVVQBIL-UHFFFAOYSA-N trisilane Chemical compound [SiH3][SiH2][SiH3] VEDJZFSRVVQBIL-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
- C01B33/021—Preparation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
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Abstract
The invention relates to a hard carbon/silicon composite anode material, a preparation method and application thereof. The hard carbon/silicon composite anode material is of a core-shell structure, takes a hard carbon/silicon precursor as a core, and is sequentially coated on a C/phosphane heterogeneous layer of the hard carbon/silicon precursor and a protective layer formed by carbon deposition; the hard carbon/silicon precursor is formed by embedding amorphous silicon into porous hard carbon particle pores; the porous hard carbon particles are prepared from a polymer and a tin-loaded bacterial cellulose compound, wherein the mass ratio of the polymer to the tin-loaded bacterial cellulose compound is 80-150: 0.01 to 15. The electronic conductivity in the hard carbon/silicon composite anode material is obviously improved by adding the tin-loaded bacterial cellulose composite, so that the lithium precipitation risk of the hard carbon/silicon composite anode material under the condition of high-rate charge and discharge is improved.
Description
Technical Field
The invention relates to the technical field of secondary batteries, in particular to a hard carbon/silicon composite anode material and a preparation method and application thereof.
Background
At present, the commercial anode material in the market is mainly graphite, but the theoretical capacity development of the graphite is close to the limit, and a novel anode material with higher specific capacity is required. Silicon has a theoretical specific capacity of up to 4200mAh/g among known lithium ion battery cathodes, and is considered as an ideal cathode candidate for the next generation. However, the problem of large volume change (volume change rate > 30%) during charge/discharge is still faced at present.
The silicon-carbon negative electrode material is a lithium ion battery silicon negative electrode material with great development prospect, and nano-scale silicon clusters are deposited and dispersed in nano (< 50 nm) carbon holes, and the nano-scale pore diameter in the porous hard carbon can greatly reduce the influence of silicon volume change in the charging/discharging process. However, since silicon is dispersed in the nano porous hard carbon, the carbon wall of the porous hard carbon cannot be in full close contact with silicon particles, and electron diffusion of the material is still weak due to poor conductivity of silicon itself, so that there is a risk of lithium precipitation under charging at a higher rate. There is a need to provide solutions to improve the electron transport efficiency of materials and reduce the risk of lithium precipitation.
Disclosure of Invention
In order to solve the technical problems, the invention provides a hard carbon/silicon composite anode material and a preparation method and application thereof.
The first object of the present invention is to provide a method for preparing a hard carbon/silicon composite anode material, comprising the steps of:
(1) Preparing porous hard carbon particles using a polymer and tin-loaded bacterial cellulose complex;
(2) Under inert atmosphere, carrying out silicon deposition on the surfaces of the porous hard carbon particles to obtain a hard carbon/silicon precursor;
(3) Uniformly mixing the hard carbon/silicon precursor and the asphalt mixture containing the phosphane to form the hard carbon/silicon precursor of which the surface is coated with the asphalt mixture containing the phosphane, and heating and carbonizing to obtain the hard carbon/silicon precursor of which the surface is coated with the C/phosphane heterogeneous layer;
(4) And performing carbon deposition on the surface of the hard carbon/silicon precursor coated with the C/phosphane heterogeneous layer to form a protective layer, thereby obtaining the hard carbon/silicon composite anode material.
In one embodiment of the invention, in step (1), at least one or more of the following conditions are satisfied:
the polymer is selected from one or more of polyvinyl alcohol, phenolic resin, epoxy resin, polyoxyethylene, furfural resin and urea-formaldehyde resin;
the mass ratio of the polymer to the tin-loaded bacterial cellulose composite is 80-150: 0.01 to 15.
In one embodiment of the present invention, in step (1), the method for preparing the tin-loaded bacterial cellulose complex comprises the steps of:
s1, preparing aminated bacterial cellulose by using bacterial cellulose, amine compounds and reaction solvents;
s2, adding a tin compound into the aminated bacterial cellulose dispersion liquid, uniformly mixing, and carrying out solid-liquid separation to obtain a solid phase;
And S3, heating and carbonizing the solid phase in inert gas to obtain the tin-loaded bacterial cellulose compound.
In one embodiment of the invention, in step S1, the specific steps for preparing an aminated bacterial cellulose are: dispersing bacterial cellulose in an alkali solution, adding amine compounds, uniformly mixing, and adding a reaction solvent for reaction to obtain aminated bacterial cellulose.
Further, in step S1, at least one or more of the following conditions are satisfied:
the alkali in the alkali solution is selected from sodium hydroxide and/or potassium hydroxide;
the amine compound is selected from one or more of diethylenetriamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine and polyethylene polyamine;
the mass/volume ratio of the bacterial cellulose to the alkali solution is 1: 2-15 kg/L;
the pH value of the alkali solution is 11-14;
the reaction solvent is selected from one or more of formaldehyde, acetaldehyde, dichloromethane, ethanol and propanol;
the reaction temperature is 50-85 ℃, and the reaction time is 2-8 hours.
In one embodiment of the invention, in step S2, at least one or more of the following conditions are satisfied:
the mass ratio of aminated bacterial cellulose to tin compound in the aminated bacterial cellulose dispersion liquid is 1: 0.01-0.8;
The tin compound is selected from one or more of stannous oxalate, stannous carbonate, stannous sulfate, stannous chloride, dibutyl tin, dimethyl tin, stannous nitrate, stannic oxide, sodium stannate and calcium stannate;
the mass-to-volume (w/w/v) ratio of the bacterial cellulose, the amine compound and the reaction solvent is 1: 0.6-3: 4.5-25 kg/kg/L;
the diameter of the bacterial cellulose is 5-500 nm, and the length of the bacterial cellulose is 10-2000 nm;
the concentration of the aminated bacterial cellulose dispersion liquid is 1-25wt%.
In one embodiment of the present invention, in step S3, the heating temperature is 400-700 ℃ and the heating time is 1-3 hours; the inert gas is selected from one or more of nitrogen, helium, xenon, radon, neon and argon.
In one embodiment of the present invention, in step (3), the phosphazene-containing asphalt mixture is prepared by the following method: adding phosphazene into the organic solvent to obtain mixed liquid, adding asphalt, and uniformly stirring to obtain an asphalt mixture containing phosphazene.
In one embodiment of the invention, in step (3), the mass ratio of the hard carbon/silicon precursor to the phosphazene-containing pitch mixture is 1:0.001 to 0.16; and/or heating and carbonizing at 300-700 ℃ for 1-8 hours; and/or the particle size of the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer is 0.1-60 mu m.
In one embodiment of the invention, in step (4), the carbon source is selected from one or more of methane, ethane, propane, acetylene, propyne, butyne, ethylene; and/or heating at 300-800 ℃ for 20 min-10 h.
The second object of the present invention is to provide a hard carbon/silicon composite anode material, wherein the hard carbon/silicon composite anode material has a core-shell structure, uses a hard carbon/silicon precursor as a core, and is coated with a C/phosphane heterogeneous layer of the hard carbon/silicon precursor and a protective layer formed by carbon deposition in sequence; the hard carbon/silicon precursor is formed by embedding amorphous silicon into porous hard carbon particle pores; the porous hard carbon particles are prepared from a polymer and tin-loaded bacterial cellulose complex.
In one embodiment of the invention, at least one or more of the following conditions are met:
the specific surface area of the hard carbon/silicon composite anode material is 0.55-12 m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 3.2-26 mu m;
the pore volume (pore volume of unit mass) of the hard carbon/silicon composite anode material is 0.02-0.48 cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.6-1.8 cm 3 /g；
The hard carbon/silicon composite anode material has at least one of a block shape, a sheet shape, a column shape and a sphere shape;
The diameter of the hard carbon/silicon precursor is 2-40 mu m;
the thickness of the C/phosphazene heterogeneous layer is 0.003-0.3 mu m;
the thickness of the protective layer is 0.005-0.6 mu m.
The third object of the invention is to provide a negative electrode sheet comprising the hard carbon/silicon composite negative electrode material or the hard carbon/silicon composite negative electrode material obtained by the preparation method.
A fourth object of the present invention is to provide a lithium ion secondary battery including the negative electrode sheet.
Compared with the prior art, the technical scheme of the invention has the following advantages:
(1) The bacterial cellulose compound loaded with tin is doped into a polymer, and tin has a low band gap, the conductivity of the bacterial cellulose is high, in addition, carbonized bacterial cellulose is formed after bacterial cellulose is carbonized, and because of the small size of bacterial fibers, the electron transmission distance can be shortened, and linear continuous electron transmission sites are provided, so that the hard carbon/silicon precursor is prepared by adding the bacterial cellulose compound loaded with Sn, and the protective layer formed by combining carbon deposition can be used for remarkably improving the electron conductivity in the hard carbon/silicon composite anode material, greatly improving the lithium precipitation condition under high multiplying power, and further improving the multiplying power performance of the hard carbon/silicon composite anode material.
(2) After the bacterial cellulose compound loaded with tin is carbonized, carbonized linear bacterial cellulose improves the stability of the hard carbon particle structure; in addition, the C/phosphane heterogeneous layer formed on the surface of the hard carbon/silicon precursor is an intrinsic P doped into the soft carbon layer on the surface, can form a stable C-P bond, is combined with a protective layer formed by carbon deposition, can better support a structure, relieves volume expansion, and can better improve the conductivity of the material.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which,
fig. 1 is a schematic structural view of a hard carbon/silicon composite anode material of the present invention.
Description of the specification reference numerals: 1. hard carbon/silicon precursor; 2. a C/phosphazene heterogeneous layer; 3. and (3) a protective layer.
Detailed Description
In order to solve the technical problems pointed out in the background art, the invention provides a hard carbon/silicon composite anode material, and a preparation method and application thereof.
The method is realized by the following steps:
the invention provides a preparation method of a hard carbon/silicon composite anode material, which comprises the following steps:
(1) Preparing porous hard carbon particles using a polymer and tin-loaded bacterial cellulose complex;
(2) Under inert atmosphere, carrying out silicon deposition on the surfaces of the porous hard carbon particles to obtain a hard carbon/silicon precursor;
(3) Uniformly mixing the hard carbon/silicon precursor and the asphalt mixture containing the phosphane to form the hard carbon/silicon precursor of which the surface is coated with the asphalt mixture containing the phosphane, heating and carbonizing, cooling, ball milling and sieving to obtain the hard carbon/silicon precursor of which the surface is coated with the C/phosphane heterogeneous layer;
(4) And performing carbon deposition on the surface of the hard carbon/silicon precursor coated with the C/phosphane heterogeneous layer to form a protective layer, thereby obtaining the hard carbon/silicon composite anode material.
In particular embodiments, in step (1), at least one or more of the following conditions are satisfied:
the polymer is selected from one or more of polyvinyl alcohol, phenolic resin, epoxy resin, polyoxyethylene, furfural resin and urea-formaldehyde resin; in the process of using the polymer, heating the temperature of the polymer to 160-280 ℃;
the mass ratio of the polymer to the tin-loaded bacterial cellulose composite is 80-150: 0.01 to 15.
In a specific embodiment, in step (1), the specific process of preparing the porous hard carbon particles: uniformly mixing the polymer and the bacterial cellulose compound loaded with tin, carbonizing for 2-12 hours at 600-1500 ℃, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m; under the high-temperature carbonization process of the polymer, carbon, hydrogen, oxygen or carbon hydroxide and the like in the polymer are gasified and volatilized under the high-temperature condition, so that partial area substances are lack, and porous hard carbon particles are formed.
In a specific embodiment, in the step (1), the preparation method of the bacterial cellulose complex loaded with tin comprises the following steps:
s1, preparing aminated bacterial cellulose by using bacterial cellulose, amine compounds and reaction solvents;
s2, adding a tin compound into the aminated bacterial cellulose dispersion liquid, uniformly mixing, and carrying out solid-liquid separation to obtain a solid phase;
and S3, placing the solid phase in a heating furnace, introducing inert gas, and heating and carbonizing to obtain the tin-loaded bacterial cellulose compound.
In a specific embodiment, in step S1, specific steps for preparing an aminated bacterial cellulose: dispersing bacterial cellulose in an alkali solution, adding amine compounds, uniformly mixing, and adding a reaction solvent for reaction to obtain aminated bacterial cellulose.
Further, in step S1, at least one or more of the following conditions are satisfied:
the alkali in the alkali solution is selected from sodium hydroxide and/or potassium hydroxide;
the amine compound is selected from one or more of diethylenetriamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine and polyethylene polyamine;
the mass/volume ratio of the bacterial cellulose to the alkali solution is 1: 2-15 kg/L;
The pH value of the alkali solution is 11-14;
the reaction temperature is 50-85 ℃, and the reaction time is 2-8 hours.
In particular embodiments, in step S2, at least one or more of the following conditions are met:
the mass ratio of aminated bacterial cellulose to tin compound in the aminated bacterial cellulose dispersion liquid is 1: 0.01-0.8;
the tin compound is selected from one or more of stannous oxalate, stannous carbonate, stannous sulfate, stannous chloride, dibutyl tin, dimethyl tin, stannous nitrate, stannic oxide, sodium stannate and calcium stannate;
the mass-to-volume (w/w/v) ratio of the bacterial cellulose, the amine compound and the reaction solvent is 1: 0.6-3: 4.5-25 kg/kg/L;
the reaction solvent is selected from one or more of formaldehyde, acetaldehyde, dichloromethane, ethanol and propanol;
the diameter of the bacterial cellulose is 5-500 nm, and the length of the bacterial cellulose is 10-2000 nm;
the concentration of the aminated bacterial cellulose dispersion liquid is 1-25wt%.
The solvent of the dispersion liquid is obtained by mixing water and ethanol in any volume ratio.
In a specific embodiment, in step S3, the heating temperature is 400-700 ℃ and the heating time is 1-3 hours; the inert gas is selected from one or more of nitrogen, helium, xenon, radon, neon and argon, and oxidation of the material can be prevented by introducing the inert gas.
In a specific embodiment, in step (3), the phosphazene-containing asphalt mixture is prepared by the following method: adding phosphazene into the organic solvent to obtain mixed liquid, adding asphalt, and uniformly stirring to obtain an asphalt mixture containing phosphazene.
Further, the organic solvent is selected from one or more of methanol, N-methyl-2-pyrrolidone, ethanol, acetaldehyde and sodium alkyl benzene sulfonate.
Further, the mass ratio of the organic solvent to the phosphazene is 100: 1-40.
In the embodiment, in the step (2), during silicon deposition, the temperature of a reaction vessel containing porous hard carbon particles is controlled to be 300-750 ℃, and the silicon deposition time is 20 min-4 h.
In the specific embodiment, in the step (2), the inert gas in the inert atmosphere is one or more of nitrogen, helium, xenon, radon, neon, argon and the like, and the inert gas is introduced into the reaction container to remove air in the system and prevent oxidation of the material.
In a specific embodiment, in the step (2), in the silicon deposition, the silicon source is a mixed gas of silane and inert gas, and the silane is one or more selected from monosilane, disilane and trisilane. The gas flow ratio of the silane to the inactive gas is 1: 0.05-8.
In a specific embodiment, in step (3), the mass ratio of the hard carbon/silicon precursor to the phosphazene-containing asphalt mixture is 1:0.001 to 0.16; and/or heating and carbonizing at 300-700 ℃ for 1-8 hours; and/or the particle size of the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer is 0.1-60 mu m; according to the invention, the intrinsic P is doped into the mixture of coal tar pitch or petroleum pitch by adding the phosphazene, and then the phosphazene doped soft carbon layer, the anisotropic, single-layer and two-dimensional high-specific-surface material is obtained by carbonization, so that the formed P-C bond is more stable, and the conductivity is more stable.
In a specific embodiment, in step (4), the carbon source is selected from one or more of methane, ethane, propane, acetylene, propyne, butyne, ethylene; and/or heating at 300-800 ℃ for 20 min-10 h.
The invention also provides a hard carbon/silicon composite anode material which is of a core-shell structure, takes a hard carbon/silicon precursor as a core, and is coated with a C/phosphazene heterogeneous layer of the hard carbon/silicon precursor and a protective layer formed by carbon deposition in sequence; the hard carbon/silicon precursor is formed by embedding amorphous silicon into porous hard carbon particle pores; the porous hard carbon particles are prepared from a polymer and tin-loaded bacterial cellulose complex.
In particular embodiments, at least one or more of the following conditions are satisfied:
the specific surface area of the hard carbon/silicon composite anode material is 0.55-12 m 2 /g；
The Dv50 of the hard carbon/silicon composite anode material is 3.2-26 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.02-0.48 cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.6-1.8 cm 3 /g；
The hard carbon/silicon composite anode material has at least one of a block shape, a sheet shape, a column shape and a sphere shape;
the diameter of the hard carbon/silicon precursor is 2-40 mu m;
the thickness of the C/phosphazene heterogeneous layer is 0.003-0.3 mu m;
the thickness of the protective layer is 0.005-0.6 mu m.
The invention provides a negative plate which comprises the hard carbon/silicon composite negative electrode material or the hard carbon/silicon composite negative electrode material obtained by the preparation method.
The negative electrode sheet is prepared by the following method: and (3) adding the hard carbon/silicon composite anode material, the graphite anode material, the conductive material, the bonding substance and deionized water into a container until the content of solid substances in a stirring tank is 40-60% (preferably 45-55%), adjusting the viscosity to be 1.0-6 Pa.s (preferably 2.5-4 Pa.s), so as to obtain mixed hard carbon/silicon anode slurry, coating the mixed hard carbon/silicon anode slurry on an anode current collector, and drying, rolling and slitting at 80-105 ℃ to obtain the hard carbon/silicon anode sheet.
In a specific embodiment, the mass percentages of the hard carbon/silicon composite anode material, the graphite anode material, the conductive material and the bonding substance are 85-99.6wt%: 0.2-7wt%: 0.2-8.0wt%;
in a specific embodiment, the conductive material is at least one of conductive carbon black, acetylene black, graphite, graphene, carbon micro-wires, carbon nano-wires, carbon micro-tubes and carbon nano-tubes;
in a specific embodiment, the bonding substance is at least one of polyvinylidene fluoride, polyimide, polyamideimide, aromatic polyamide, polyacrylic acid, lithium polyacrylate, carboxymethyl cellulose, styrene-butadiene based rubber, fluorine based rubber, polyvinyl alcohol, lithium alginate, and sodium alginate;
in a specific embodiment, the compacted density of the cut hard carbon/silicon negative plate is 1.40-1.80 g/cm 3 The thickness is 35-500 μm, preferably 1.55-1.65 g/cm 3 The thickness is 60-180 mu m;
in a specific embodiment, the negative current collector is one or more of copper foil, nickel foam/copper foil, zinc-plated copper foil, nickel-plated copper foil, carbon-coated copper foil, nickel foil and titanium foil. Preferably copper foil, nickel-plated copper foil, carbon-coated copper foil; the thickness of the negative electrode current collector is 1-25 mu m;
The invention provides a lithium ion secondary battery, which comprises the negative plate.
In a specific embodiment, the lithium-ion secondary battery is prepared by the following method: and sequentially stacking and winding the positive electrode plate, the isolating film and the negative electrode plate to obtain a bare cell and an ultrasonic welding tab, putting the bare cell into a battery shell, drying at 90-120 ℃ to remove moisture, injecting electrolyte into the battery shell, packaging, forming and separating the volume to obtain the lithium ion secondary battery.
In a specific embodiment, the positive electrode active material in the positive electrode sheet is at least one of lithium nickel manganese oxide, lithium nickel cobalt aluminate, lithium cobalt oxide, lithium iron phosphate, lithium iron manganese fluorophosphate and lithium nickel iron manganese oxide;
in a specific embodiment, the separator is a polymer separator of at least one of polyethylene, polypropylene, polyacrylonitrile, polyvinyl alcohol, polyarylethersulfone, polyvinylidene fluoride.
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
The embodiment provides a hard carbon/silicon composite anode material, and a preparation method and application thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
The preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) The phenolic resin is heated to 220 ℃ and the mass ratio of the phenolic resin to the bacterial cellulose compound loaded with tin is 100:5, uniformly mixing, carbonizing for 6 hours at 1100 ℃ in a heating furnace, cooling, ball milling and sieving to obtain particles with the particle size of 2-40 mu m, namely the particles of Kong Yingtan;
(2) The porous hard carbon particles are sent into a fluidized bed, the temperature of the fluidized bed is controlled at 450 ℃, inert gas argon is introduced to remove air to prevent oxidation, the pressure of a deposition area of the fluidized bed is 500Pa, and mixed silane is introduced to deposit silicon for 2h, so that a hard carbon/silicon precursor is obtained; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1:0.04, uniformly stirring and mixing (coating hard carbon/silicon precursor), carbonizing for 4 hours at 380 ℃ in a heating furnace, cooling, ball milling, sieving, and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
Wherein, in the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 10kg/L of mass/volume ratio in a sodium hydroxide solution with pH of 12.6, adding diethylenetriamine, stirring, adding 65wt% formaldehyde solution, stirring, reacting at 55 ℃ for 6h, centrifuging, and taking precipitate to obtain aminated bacterial cellulose.
(2) Aminated bacterial cellulose dispersion (the content is 14.5wt%, the solvent is obtained by mixing water and ethanol in a volume ratio of 1:1), stannous nitrate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound;
(3) and (3) conveying the Sn-loaded bacterial cellulose compound into a heating furnace, introducing inert gas argon, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of the bacterial cellulose, the diethylenetriamine and the formaldehyde is 1 according to the w/w/v ratio: 2.5:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the stannous nitrate in the aminated bacterial cellulose dispersion liquid is 1:0.03;
in the step (3), the preparation method of the coal tar pitch mixture comprises the following steps: adding 15 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 5% by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain a coal tar pitch mixture;
Wherein the specific surface area of the hard carbon/silicon composite anode material is 2.3 m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 8.5 mu m;
the saidThe pore volume of the hard carbon/silicon composite anode material is 0.15cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.91cm 3 /g；
The diameter of the hard carbon/silicon precursor is 6 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.01 mu m;
the thickness of the protective layer was 0.02 μm.
Example 2
The embodiment provides a hard carbon/silicon composite anode material and a preparation method thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
the preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) The phenolic resin is heated to 220 ℃ and the mass ratio of the phenolic resin to the bacterial cellulose compound loaded with tin is 100:8, uniformly mixing, carbonizing for 6 hours at 1100 ℃ in a heating furnace, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m;
(2) The porous hard carbon particles are sent into a fluidized bed, the temperature of the fluidized bed is controlled to be 500 ℃, inert gas argon is introduced to remove air to prevent oxidation, the pressure of a deposition area of the fluidized bed is 500Pa, and mixed silane is introduced to deposit silicon for 2h, so that a hard carbon/silicon precursor is obtained; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1:0.04, uniformly stirring and mixing (coating hard carbon/silicon precursor), carbonizing for 4 hours at 380 ℃ in a heating furnace, cooling, ball milling, sieving, and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
Wherein, in the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 10kg/L of mass/volume ratio in a sodium hydroxide solution with pH of 12.3, adding diethylenetriamine, stirring, adding 65wt% formaldehyde solution, stirring, reacting at 55 ℃ for 6h, centrifuging, and taking precipitate to obtain aminated bacterial cellulose.
(2) Aminated bacterial cellulose dispersion (the content is 14.5wt%, the solvent is obtained by mixing water and ethanol in a volume ratio of 1:1), stannous nitrate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound.
(3) And (3) conveying the Sn-loaded bacterial cellulose compound into a heating furnace, introducing inert gas argon, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of the bacterial cellulose, the diethylenetriamine and the formaldehyde is 1 according to the w/w/v ratio: 2.5:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the stannous nitrate in the aminated bacterial cellulose dispersion liquid is 1:0.03;
in the step (3), the preparation method of the coal-tar pitch mixture comprises the following steps: adding 15 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 5% by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain a coal tar pitch mixture;
wherein the specific surface area of the hard carbon/silicon composite anode material is 3.3 m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 8.7 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.19cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.92cm 3 /g；
The diameter of the hard carbon/silicon precursor is 6 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.02 mu m;
the thickness of the protective layer was 0.02 μm.
Example 3
The embodiment provides a hard carbon/silicon composite anode material and a preparation method thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
the preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) The phenolic resin is heated to 220 ℃ and the mass ratio of the phenolic resin to the bacterial cellulose compound loaded with tin is 100:10, uniformly mixing, carbonizing for 6 hours at 1100 ℃ in a heating furnace, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m;
(2) Delivering porous hard carbon particles into a fluidized bed, controlling the temperature of the fluidized bed at 550 ℃, introducing inert gas argon to remove air to prevent oxidation, controlling the pressure of a deposition area of the fluidized bed at 500Pa, and introducing mixed silane to deposit silicon for 2h to obtain a hard carbon/silicon precursor; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1:0.04, uniformly mixing (coating hard carbon/silicon precursor), then delivering to a heating furnace, carbonizing for 4 hours at 380 ℃, cooling, ball milling, sieving, and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
Wherein, in the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 10kg/L of mass/volume ratio in a mixed solution of sodium oxide and potassium hydroxide with the pH of 12.4, adding diethylenetriamine, stirring, adding 65wt% of formaldehyde solution, stirring, reacting at 55 ℃ for 6 hours, centrifuging, and taking precipitate to obtain aminated bacterial cellulose.
(2) Aminated bacterial cellulose dispersion (the content is 14.5wt%, the solvent is obtained by mixing water and ethanol in a volume ratio of 1:1), stannous nitrate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound.
(3) And (3) conveying the Sn-loaded bacterial cellulose compound into a heating furnace, introducing inert gas argon, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of the bacterial cellulose, the diethylenetriamine and the formaldehyde is 1 according to the w/w/v ratio: 2.5:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the tin compound in the aminated bacterial cellulose dispersion liquid is 1:0.03;
in the step (3), the preparation method of the coal-tar pitch mixture comprises the following steps: adding 15 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 5% by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain a coal tar pitch mixture;
wherein the specific surface area of the hard carbon/silicon composite anode material is 2.2m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 9.4 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.15cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 1.02cm 3 /g；
The diameter of the hard carbon/silicon precursor is 7 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.02 mu m;
the thickness of the protective layer was 0.03 μm.
Example 4
The embodiment provides a hard carbon/silicon composite anode material and a preparation method thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
the preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) The epoxy resin was heated to 220 ℃ and mixed with tin-loaded bacterial cellulose in a mass ratio of 100:5, uniformly mixing, carbonizing for 5 hours at 1300 ℃ in a heating furnace, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m;
(2) The porous hard carbon particles are sent into a fluidized bed, the temperature of the fluidized bed is controlled at 450 ℃, inert gas argon is introduced to remove air so as to prevent oxidation, the pressure of a deposition area of the fluidized bed is 500Pa, and mixed silane is introduced to deposit silicon for 2h, so that a hard carbon/silicon precursor is obtained; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1:0.08, uniformly stirring and mixing (coating hard carbon/silicon precursor), then delivering to a heating furnace, carbonizing for 4 hours at 400 ℃, cooling, ball milling, sieving, and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
Wherein, in the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 8kg/L of mass/volume ratio in a sodium hydroxide solution with pH of 13.1, adding ethylenediamine, stirring, adding 65wt% formaldehyde solution, stirring, reacting at 55 ℃ for 6h, centrifuging, and collecting precipitate to obtain aminated bacterial cellulose;
(2) aminated bacterial cellulose dispersion (the content is 16.7wt%, the solvent is water and ethanol are mixed according to the volume ratio of 1:1), stannous sulfate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound;
(3) and (3) conveying the Sn-loaded bacterial cellulose compound into a heating furnace, introducing inert gas argon, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of bacterial cellulose, ethylenediamine and formaldehyde is 1 according to the w/w/v ratio: 3.8:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the tin compound in the aminated bacterial cellulose dispersion liquid is 1:0.06.
In the step (3), the preparation method of the coal tar pitch mixture comprises the following steps: adding 10 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 0.05 part by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain a coal tar pitch mixture;
wherein the specific surface area of the hard carbon/silicon composite anode material is 2.5m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 8.4 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.17cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.93cm 3 /g；
The diameter of the hard carbon/silicon precursor is 6 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.01 mu m;
the thickness of the protective layer was 0.02 μm.
Example 5
The embodiment provides a hard carbon/silicon composite anode material and a preparation method thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
the preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) Heating the epoxy resin to 220 ℃, and mixing the epoxy resin with the bacterial cellulose compound loaded with tin according to the mass ratio of 100:8, uniformly mixing, carbonizing for 5 hours at 1300 ℃ in a heating furnace, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m;
(2) The porous hard carbon particles are sent into a fluidized bed, the temperature of the fluidized bed is controlled at 500 ℃, inert gas argon is introduced to remove air so as to prevent oxidation, the pressure of a deposition area of the fluidized bed is 500Pa, and mixed silane is introduced to deposit silicon for 2h, so that a hard carbon/silicon precursor is obtained; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1: uniformly mixing 0.08 (coating hard carbon/silicon precursor), carbonizing for 4 hours at 400 ℃ in a heating furnace, cooling, ball milling, sieving and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 4 hours to obtain the hard carbon/silicon composite anode material.
Wherein, in the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 8kg/L of mass/volume ratio in a sodium hydroxide solution with pH of 13.1, adding ethylenediamine, stirring, adding 65wt% formaldehyde solution, stirring, reacting at 75 ℃ for 6 hours, centrifuging, and collecting precipitate to obtain aminated bacterial cellulose;
(2) aminated bacterial cellulose dispersion (the content is 16.7wt%, the solvent is water and ethanol are mixed according to the volume ratio of 1:1), stannous sulfate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound;
(3) and (3) conveying the Sn-loaded bacterial cellulose compound into a heating furnace, introducing inert gas argon, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of bacterial cellulose, ethylenediamine and formaldehyde is 1 according to the w/w/v ratio: 3.8:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the tin compound in the aminated bacterial cellulose dispersion liquid is 1:0.06;
in the step (3), the preparation method of the coal tar pitch mixture comprises the following steps: adding 10 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 5% by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain coal tar pitch compound;
wherein the specific surface area of the hard carbon/silicon composite anode material is 2.6m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 8.8 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.18cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.10cm 3 /g；
The diameter of the hard carbon/silicon precursor is 8 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.011 mu m;
the thickness of the protective layer was 0.02 μm.
Example 6
The embodiment provides a hard carbon/silicon composite anode material and a preparation method thereof, and the hard carbon/silicon composite anode material comprises the following specific steps:
the preparation method of the hard carbon/silicon composite anode material comprises the following steps:
(1) Heating the epoxy resin to 220 ℃, and mixing the epoxy resin with the bacterial cellulose compound loaded with tin according to the mass ratio of 100:10, uniformly mixing, carbonizing for 5 hours at 1300 ℃ in a heating furnace, cooling, ball milling and sieving to obtain porous hard carbon particles with the particle size of 2-40 mu m;
(2) The porous hard carbon particles are sent into a fluidized bed, the temperature of the fluidized bed is controlled at 550 ℃, inert gas argon is introduced to remove air so as to prevent oxidation, the pressure of a deposition area of the fluidized bed is 500Pa, and mixed silane is introduced to deposit silicon for 2h, so that a hard carbon/silicon precursor is obtained; the mixed silane is mixed gas of monosilane and inert gas argon, and the gas flow ratio of monosilane to inert gas argon is 1:3, a step of;
(3) Mixing hard carbon/silicon precursor and coal pitch mixture in a mass ratio of 1:0.08, uniformly stirring and mixing (coating hard carbon/silicon precursor), then delivering to a heating furnace, carbonizing for 4 hours at 400 ℃, cooling, ball milling, sieving, and demagnetizing to obtain particles with the size of 0.1-60 mu m, namely the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer;
(4) And controlling the temperature of the fluidized bed at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
In the step (1), the preparation method of the bacterial cellulose compound loaded with tin comprises the following steps:
(1) bacterial cellulose was prepared according to 1: dispersing 8kg/L of mass/volume ratio in an alkaline solution (sodium hydroxide) with the pH of 13.1, adding ethylenediamine, stirring, adding 65wt% of formaldehyde solution, stirring, reacting at 55 ℃ for 6 hours, centrifuging, and taking a precipitate to obtain aminated bacterial cellulose;
(2) Aminated bacterial cellulose dispersion (the content is 16.7wt percent, the solvent is obtained by mixing water and ethanol in a ratio of 1:1), stannous sulfate is added, stirring and suction filtration are carried out to obtain a precipitate, and the precipitate is the Sn-loaded bacterial cellulose compound;
(3) and (3) conveying the Sn-loaded bacterial cellulose compound to a heating furnace, introducing inert gas, carbonizing for 2 hours at 500 ℃, and cooling to obtain the Sn-loaded bacterial cellulose compound.
Wherein in the step (1), the addition amount of bacterial cellulose, ethylenediamine and formaldehyde is 1 according to the w/w/v ratio: 3.8:12kg/kg/L are sequentially added into a heating furnace;
in the step (2), the mass ratio of the aminated bacterial cellulose to the tin compound in the aminated bacterial cellulose dispersion liquid is 1:0.06;
the preparation method of the coal tar pitch mixture in the step (3) comprises the following steps: adding 10 parts by mass of phosphazene into 100 parts by mass of methanol to obtain methanol mixed liquid, adding 5% by mass of methanol mixed liquid of coal tar pitch, stirring, and removing alcohol at 75 ℃ to obtain coal tar pitch mixture;
wherein the specific surface area of the hard carbon/silicon composite anode material is 2.4m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 9.2 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.18cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.95cm 3 /g；
The diameter of the hard carbon/silicon precursor is 7 μm;
the thickness of the C/phosphazene heterogeneous layer is 0.01 mu m;
the thickness of the protective layer was 0.02 μm.
Comparative example 1
The difference from example 4 is that: step (1) was not added with tin-loaded bacterial cellulose complex.
Comparative example 2
The difference from example 4 is that: in the step (3), the mixed liquid of methanol is not added with phosphazene, and a C/phosphazene heterogeneous layer is not formed.
Comparative example 3
The difference from example 1 is that: and (3) directly conveying the hard carbon/silicon precursor in the step (2) to a fluidized bed, controlling the temperature at 500 ℃, introducing a second carbon source butyne, and depositing for 1h to obtain the hard carbon/silicon composite anode material.
Hard carbon/silicon composite anode material application:
(1) Preparation of hard carbon silicon/graphite: the preparation method comprises the steps of placing a negative electrode material (a hard carbon/silicon composite negative electrode material and a graphite negative electrode material in a mass ratio of 1:9 in an embodiment/comparative example), a conductive material (80 wt% of carbon black and 20wt% of carbon nano tubes) in a stirring tank, adding a bonding substance (50 wt% of carboxymethyl cellulose and 50wt% of polyacrylic acid), mixing the negative electrode material, the conductive material and the bonding substance according to mass percentages of 95.5wt%, 1.5wt% and 3.0wt%, adding deionized water in a container until the content of solid substances is 50%, regulating the viscosity to be 3Pa.s, obtaining slurry, coating the slurry on a copper foil, and drying, rolling and slitting at the temperature of 95 ℃, 90 ℃ and 88 ℃ in four sections, thus obtaining the hard carbon silicon/graphite negative electrode plate.
(2) And (3) manufacturing a battery: positive plate (containing 97.8wt% nickel cobalt lithium manganate LiNi) 0.8 Co 0.1 Mn 0.1 O 2 ) Sequentially stacking and winding a polyethylene isolating film and a hard carbon silicon/graphite negative plate to obtain a bare cell and an ultrasonic welding tab, putting the bare cell into a battery shell, drying at 105 ℃ for 40 hours to remove moisture, injecting electrolyte into the battery shell, packaging, and performing constant-current charging to 3.75V at 0.1C current at 45 ℃ and constant-current charging to 4.20V at 0.5C; and discharging at the temperature of 25 ℃ with a constant current of 1C+0.1C to 2.80V, and carrying out capacity division to obtain the lithium ion secondary battery.
Performance test:
(1) The powder resistances of examples 1 to 6 and comparative examples 1 to 3 were tested by a four-probe method using a powder resistance test system (test conditions: pressure 180MPa, 25 ℃ C., relative humidity < 10%).
(2) The electrochemical test system performs: under normal temperature and pressure environment, the secondary batteries of examples 1-6 and comparative examples 1-3 are divided into 1.2C, 1.5C, 1.8C and 2C constant current charging to voltage of 4.20V, then 4.20V constant voltage charging to current of less than 0.02C, then 1.0C discharging to 2.8V, and charging and discharging for 5 times, wherein the last time is the case of 1.2C, 1.5C, 1.8C and 2C constant current charging to voltage of 4.20V, then 4.20V constant voltage charging to current of less than 0.02C, and the interface of the hard carbon silicon/graphite negative electrode sheet with lithium embedded under full charging of 4.20V is disassembled.
TABLE 1 powder resistance conditions for examples 1-6 and comparative examples 1-3
Table 2 examples 1 to 6 and comparative examples 1 to 3 show the conditions of the anode interface under full charge at different magnifications (yellow interface is not precipitated lithium, white spots are precipitated lithium)
According to the comparison treatment of the embodiment and the comparative example, the electronic conductivity of the inside of the hard carbon/silicon composite anode material is improved by adding the bacterial cellulose compound loaded with tin and the C/phosphane heterogeneous layer formed on the surface of the hard carbon/silicon precursor through surface treatment, and the risk of interfacial lithium precipitation is improved under the high-rate conditions of 1.5C, 1.8C and 2.0C, so that the charging rate performance of the hard carbon/silicon composite anode material is improved.
Example 4 compared to comparative example 1, the bacterial cellulose composite without tin loading in comparative example 1 produced a hard carbon/silicon composite anode material having a higher resistance than example 4; at high rates, lithium evolution occurred in comparative example 1. It is demonstrated that the lithium precipitation at high rates can be improved and the conductivity enhanced by using tin-loaded bacterial cellulose composites to prepare hard carbon/silicon composite anode materials.
Example 4 compared with comparative example 2, no phosphazene was added in comparative example 2, and thus no C/phosphazene heterogeneous layer was formed, and the resistance of comparative example 2 was also higher than that of example 4; under the condition of high multiplying power, the lithium precipitation phenomenon occurs in the comparative example. By using the phosphazene, a stable C-P bond is formed, a supporting structure can be well realized, the volume expansion is relieved, the lithium precipitation phenomenon of the electrode is improved, and the conductivity of the cathode material is improved.
In example 4, the negative electrode material obtained in comparative example 3 was increased in resistance and more serious in lithium precipitation phenomenon, compared with comparative example 3, in absence of step (3). It is explained that the encapsulation of the coal tar pitch mixture is not performed, resulting in that the carbon wall and the silicon particles are not completely in close contact, resulting in serious lithium precipitation.
In conclusion, according to the invention, the bacterial cellulose compound loaded with tin and the phosphazene are added to form the C/phosphazene heterogeneous layer, and the C/phosphazene heterogeneous layer and the phosphazene are synergistic to solve the problem of lithium precipitation of the electrode under the condition of high multiplying power of the anode material, and also enhance the conductivity of the anode material.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (10)
1. The preparation method of the hard carbon/silicon composite anode material is characterized by comprising the following steps of:
(1) Preparing porous hard carbon particles using a polymer and tin-loaded bacterial cellulose complex;
(2) Under inert atmosphere, carrying out silicon deposition on the surfaces of the porous hard carbon particles to obtain a hard carbon/silicon precursor;
(3) Uniformly mixing the hard carbon/silicon precursor and the asphalt mixture containing the phosphane to form the hard carbon/silicon precursor of which the surface is coated with the asphalt mixture containing the phosphane, and heating and carbonizing to obtain the hard carbon/silicon precursor of which the surface is coated with the C/phosphane heterogeneous layer;
(4) And performing carbon deposition on the surface of the hard carbon/silicon precursor coated with the C/phosphane heterogeneous layer to form a protective layer, thereby obtaining the hard carbon/silicon composite anode material.
2. The method of claim 1, wherein in step (1), at least one or more of the following conditions are satisfied:
the polymer is selected from one or more of polyvinyl alcohol, phenolic resin, epoxy resin, polyoxyethylene, furfural resin and urea-formaldehyde resin;
the mass ratio of the polymer to the tin-loaded bacterial cellulose composite is 80-150: 0.01-15;
the method for preparing the porous hard carbon particles comprises heating and carbonizing at 600-1500 ℃;
the particle size of the porous hard carbon particles is 2-40 mu m.
3. The method of claim 1, wherein in step (1), the method of preparing the tin-loaded bacterial cellulose complex comprises the steps of:
S1, preparing aminated bacterial cellulose by utilizing bacterial cellulose, amine compounds and reaction solvents;
s2, adding a tin compound into the aminated bacterial cellulose dispersion liquid, uniformly mixing, and carrying out solid-liquid separation to obtain a solid phase;
and S3, heating and carbonizing the solid phase in inert gas to obtain the tin-loaded bacterial cellulose compound.
4. A method according to claim 3, wherein in step S1 at least one or more of the following conditions are met:
the amine compound is selected from one or more of diethylenetriamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine and polyethylene polyamine;
the reaction temperature is 50-85 ℃, and the reaction time is 2-8 hours.
5. A method according to claim 3, wherein in step S2 at least one or more of the following conditions are met:
the mass ratio of aminated bacterial cellulose to tin compound in the aminated bacterial cellulose dispersion liquid is 1: 0.01-0.8;
the tin compound is selected from one or more of stannous oxalate, stannous carbonate, stannous sulfate, stannous chloride, dibutyl tin, dimethyl tin, stannous nitrate, stannic oxide, sodium stannate and calcium stannate;
The mass volume ratio of the bacterial cellulose to the amine compound to the reaction solvent is 1: 0.6-3: 4.5-25 kg/kg/L;
the diameter of the bacterial cellulose is 5-500 nm, and the length of the bacterial cellulose is 10-2000 nm;
the concentration of the aminated bacterial cellulose dispersion liquid is 1-25wt% of the solvent.
6. The method of claim 1, wherein in step (3), at least one or more of the following conditions are satisfied:
the phosphazene-containing asphalt mixture is prepared by the following method: adding phosphazene into an organic solvent to obtain mixed liquid, adding asphalt, and uniformly stirring to obtain an asphalt mixture containing phosphazene;
the mass ratio of the hard carbon/silicon precursor to the phosphazene-containing asphalt mixture is 1:0.001 to 0.16;
the heating carbonization temperature is 300-700 ℃, and the heating carbonization time is 1-8 hours;
the particle size of the hard carbon/silicon precursor with the surface being the C/phosphane heterogeneous layer is 0.1-60 mu m.
7. The hard carbon/silicon composite anode material is characterized by being of a core-shell structure, taking a hard carbon/silicon precursor as a core, and a C/phosphazene heterogeneous layer and a protective layer formed by carbon deposition, wherein the C/phosphazene heterogeneous layer and the protective layer are sequentially coated on the hard carbon/silicon precursor; the hard carbon/silicon precursor is formed by embedding amorphous silicon into porous hard carbon particle pores; the porous hard carbon particles are prepared from a polymer and tin-loaded bacterial cellulose complex.
8. The hard carbon/silicon composite anode material according to claim 7, wherein at least one or more of the following conditions are satisfied:
the specific surface area of the hard carbon/silicon composite anode material is 0.55-12 m 2 /g；
The Dv50 value of the hard carbon/silicon composite anode material is 3.2-26 mu m;
the pore volume of the hard carbon/silicon composite anode material is 0.02-0.48 cm 3 /g；
The tap density of the hard carbon/silicon composite anode material is 0.6-1.8 cm 3 /g；
The hard carbon/silicon composite anode material has at least one of a block shape, a sheet shape, a column shape and a sphere shape;
the diameter of the hard carbon/silicon precursor is 2-40 mu m;
the thickness of the C/phosphazene heterogeneous layer is 0.003-0.3 mu m;
the thickness of the protective layer is 0.005-0.6 mu m.
9. A negative electrode sheet comprising the hard carbon/silicon composite negative electrode material obtained by the production method according to any one of claims 1 to 6 or comprising the hard carbon/silicon composite negative electrode material according to claim 7 or 8.
10. A secondary battery comprising the negative electrode sheet described in claim 9.
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