CN117529450A - Composite particles, method for producing same, and use thereof - Google Patents
Composite particles, method for producing same, and use thereof Download PDFInfo
- Publication number
- CN117529450A CN117529450A CN202280042784.7A CN202280042784A CN117529450A CN 117529450 A CN117529450 A CN 117529450A CN 202280042784 A CN202280042784 A CN 202280042784A CN 117529450 A CN117529450 A CN 117529450A
- Authority
- CN
- China
- Prior art keywords
- composite particles
- silicon
- carbon
- particles
- negative electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011246 composite particle Substances 0.000 title claims abstract description 250
- 238000004519 manufacturing process Methods 0.000 title claims description 29
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 152
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 143
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 139
- 239000010703 silicon Substances 0.000 claims abstract description 138
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 119
- 239000002245 particle Substances 0.000 claims abstract description 101
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 49
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 47
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000001301 oxygen Substances 0.000 claims abstract description 42
- 239000011247 coating layer Substances 0.000 claims abstract description 34
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 23
- 229910052681 coesite Inorganic materials 0.000 claims abstract description 20
- 229910052906 cristobalite Inorganic materials 0.000 claims abstract description 20
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 20
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 20
- 229910052682 stishovite Inorganic materials 0.000 claims abstract description 20
- 229910052905 tridymite Inorganic materials 0.000 claims abstract description 20
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 claims abstract description 15
- 238000001237 Raman spectrum Methods 0.000 claims abstract description 8
- 239000007789 gas Substances 0.000 claims description 77
- 238000000576 coating method Methods 0.000 claims description 53
- 229920000642 polymer Polymers 0.000 claims description 52
- 238000000034 method Methods 0.000 claims description 51
- 239000011248 coating agent Substances 0.000 claims description 49
- 239000010410 layer Substances 0.000 claims description 45
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 44
- 229910001416 lithium ion Inorganic materials 0.000 claims description 44
- 239000007773 negative electrode material Substances 0.000 claims description 43
- 239000000203 mixture Substances 0.000 claims description 40
- 239000011148 porous material Substances 0.000 claims description 35
- 229930195733 hydrocarbon Natural products 0.000 claims description 34
- 150000002430 hydrocarbons Chemical class 0.000 claims description 34
- 239000004215 Carbon black (E152) Substances 0.000 claims description 30
- 229910002804 graphite Inorganic materials 0.000 claims description 29
- 239000010439 graphite Substances 0.000 claims description 29
- 239000010954 inorganic particle Substances 0.000 claims description 16
- 238000009826 distribution Methods 0.000 claims description 13
- 239000001307 helium Substances 0.000 claims description 11
- 229910052734 helium Inorganic materials 0.000 claims description 11
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 11
- 238000001228 spectrum Methods 0.000 claims description 11
- 238000004458 analytical method Methods 0.000 claims description 10
- 238000000634 powder X-ray diffraction Methods 0.000 claims description 10
- 238000002441 X-ray diffraction Methods 0.000 claims description 7
- 230000001186 cumulative effect Effects 0.000 claims description 7
- 230000002209 hydrophobic effect Effects 0.000 claims description 7
- 230000001590 oxidative effect Effects 0.000 claims description 7
- 239000006229 carbon black Substances 0.000 claims description 5
- 229910017488 Cu K Inorganic materials 0.000 claims description 3
- 229910017541 Cu-K Inorganic materials 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 35
- 239000006185 dispersion Substances 0.000 abstract description 13
- 238000006388 chemical passivation reaction Methods 0.000 abstract description 6
- 238000005259 measurement Methods 0.000 description 38
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 36
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 30
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 28
- 238000006243 chemical reaction Methods 0.000 description 28
- 230000003647 oxidation Effects 0.000 description 27
- 238000007254 oxidation reaction Methods 0.000 description 27
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 24
- 229910010271 silicon carbide Inorganic materials 0.000 description 23
- 229910052786 argon Inorganic materials 0.000 description 18
- 239000001257 hydrogen Substances 0.000 description 18
- 229910052739 hydrogen Inorganic materials 0.000 description 18
- 239000002002 slurry Substances 0.000 description 18
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 17
- 239000002904 solvent Substances 0.000 description 16
- 238000001179 sorption measurement Methods 0.000 description 15
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 14
- 239000012298 atmosphere Substances 0.000 description 14
- -1 i.e. Substances 0.000 description 14
- 229910052744 lithium Inorganic materials 0.000 description 14
- 229910052757 nitrogen Inorganic materials 0.000 description 14
- 239000002153 silicon-carbon composite material Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 13
- 230000007423 decrease Effects 0.000 description 12
- 230000000704 physical effect Effects 0.000 description 12
- 239000000126 substance Substances 0.000 description 12
- 239000011230 binding agent Substances 0.000 description 10
- 238000005229 chemical vapour deposition Methods 0.000 description 10
- 230000008602 contraction Effects 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 9
- 239000002345 surface coating layer Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000011156 evaluation Methods 0.000 description 8
- 229910000077 silane Inorganic materials 0.000 description 8
- 239000012752 auxiliary agent Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000010408 film Substances 0.000 description 7
- 239000011888 foil Substances 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 239000012071 phase Substances 0.000 description 7
- 238000004626 scanning electron microscopy Methods 0.000 description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 6
- 238000001069 Raman spectroscopy Methods 0.000 description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 6
- 239000002585 base Substances 0.000 description 6
- 238000000354 decomposition reaction Methods 0.000 description 6
- 239000003792 electrolyte Substances 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 229910052814 silicon oxide Inorganic materials 0.000 description 6
- 229920003048 styrene butadiene rubber Polymers 0.000 description 6
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 239000002482 conductive additive Substances 0.000 description 5
- 238000012937 correction Methods 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 238000009830 intercalation Methods 0.000 description 5
- 230000002687 intercalation Effects 0.000 description 5
- 238000005240 physical vapour deposition Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000003825 pressing Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 229920000049 Carbon (fiber) Polymers 0.000 description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
- 239000002174 Styrene-butadiene Substances 0.000 description 4
- 239000001768 carboxy methyl cellulose Substances 0.000 description 4
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 4
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000009831 deintercalation Methods 0.000 description 4
- 239000003085 diluting agent Substances 0.000 description 4
- 239000008151 electrolyte solution Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 229910021385 hard carbon Inorganic materials 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 3
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 description 3
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000006230 acetylene black Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000006183 anode active material Substances 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000000231 atomic layer deposition Methods 0.000 description 3
- 239000002134 carbon nanofiber Substances 0.000 description 3
- 229910052809 inorganic oxide Inorganic materials 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 230000002427 irreversible effect Effects 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000011255 nonaqueous electrolyte Substances 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- 230000035484 reaction time Effects 0.000 description 3
- 238000001507 sample dispersion Methods 0.000 description 3
- 239000000600 sorbitol Substances 0.000 description 3
- 241000894007 species Species 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 238000004627 transmission electron microscopy Methods 0.000 description 3
- 239000012808 vapor phase Substances 0.000 description 3
- PUPZLCDOIYMWBV-UHFFFAOYSA-N (+/-)-1,3-Butanediol Chemical compound CC(O)CCO PUPZLCDOIYMWBV-UHFFFAOYSA-N 0.000 description 2
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 description 2
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 2
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- 229910003921 SiC(111) Inorganic materials 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 240000004584 Tamarindus indica Species 0.000 description 2
- 235000004298 Tamarindus indica Nutrition 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910021417 amorphous silicon Inorganic materials 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 229910002090 carbon oxide Inorganic materials 0.000 description 2
- 239000012159 carrier gas Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000011889 copper foil Substances 0.000 description 2
- 238000001739 density measurement Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical compound C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 description 2
- 238000011549 displacement method Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 2
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- LNTHITQWFMADLM-UHFFFAOYSA-N gallic acid Chemical compound OC(=O)C1=CC(O)=C(O)C(O)=C1 LNTHITQWFMADLM-UHFFFAOYSA-N 0.000 description 2
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 2
- 229910052912 lithium silicate Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 239000013618 particulate matter Substances 0.000 description 2
- 229920001568 phenolic resin Polymers 0.000 description 2
- 239000005011 phenolic resin Substances 0.000 description 2
- 229920002239 polyacrylonitrile Polymers 0.000 description 2
- 239000005518 polymer electrolyte Substances 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 239000007774 positive electrode material Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000005060 rubber Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000011856 silicon-based particle Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000011550 stock solution Substances 0.000 description 2
- 238000005211 surface analysis Methods 0.000 description 2
- 238000002411 thermogravimetry Methods 0.000 description 2
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- QMGYPNKICQJHLN-UHFFFAOYSA-M Carboxymethylcellulose cellulose carboxymethyl ether Chemical compound [Na+].CC([O-])=O.OCC(O)C(O)C(O)C(O)C=O QMGYPNKICQJHLN-UHFFFAOYSA-M 0.000 description 1
- 244000205754 Colocasia esculenta Species 0.000 description 1
- 235000006481 Colocasia esculenta Nutrition 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 238000004566 IR spectroscopy Methods 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910013684 LiClO 4 Inorganic materials 0.000 description 1
- 229910013733 LiCo Inorganic materials 0.000 description 1
- 229910013820 LiCo0.8Mn0.1Ni0.1O2 Inorganic materials 0.000 description 1
- 229910012733 LiCo1/3Mn1/3Ni1/3O2 Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910012424 LiSO 3 Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- DUFKCOQISQKSAV-UHFFFAOYSA-N Polypropylene glycol (m w 1,200-3,000) Chemical compound CC(O)COC(C)CO DUFKCOQISQKSAV-UHFFFAOYSA-N 0.000 description 1
- 241000722270 Regulus Species 0.000 description 1
- 229910018540 Si C Inorganic materials 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- OLBVUFHMDRJKTK-UHFFFAOYSA-N [N].[O] Chemical compound [N].[O] OLBVUFHMDRJKTK-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000005260 alpha ray Effects 0.000 description 1
- 235000001014 amino acid Nutrition 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000005250 beta ray Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004305 biphenyl Substances 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 235000019437 butane-1,3-diol Nutrition 0.000 description 1
- 229920005549 butyl rubber Polymers 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002678 cellulose Chemical class 0.000 description 1
- 239000001913 cellulose Chemical class 0.000 description 1
- 239000006255 coating slurry Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000007771 core particle Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 150000002016 disaccharides Chemical class 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229940074391 gallic acid Drugs 0.000 description 1
- 235000004515 gallic acid Nutrition 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 125000001475 halogen functional group Chemical group 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 239000002052 molecular layer Substances 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 230000002794 monomerizing effect Effects 0.000 description 1
- 150000002772 monosaccharides Chemical class 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 229920001542 oligosaccharide Polymers 0.000 description 1
- 150000002482 oligosaccharides Chemical class 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920003196 poly(1,3-dioxolane) Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920002627 poly(phosphazenes) Polymers 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 229920001451 polypropylene glycol Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 235000020004 porter Nutrition 0.000 description 1
- FVSKHRXBFJPNKK-UHFFFAOYSA-N propionitrile Chemical compound CCC#N FVSKHRXBFJPNKK-UHFFFAOYSA-N 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- CVHZOJJKTDOEJC-UHFFFAOYSA-N saccharin Chemical class C1=CC=C2C(=O)NS(=O)(=O)C2=C1 CVHZOJJKTDOEJC-UHFFFAOYSA-N 0.000 description 1
- 235000019204 saccharin Nutrition 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 239000002109 single walled nanotube Substances 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000011410 subtraction method Methods 0.000 description 1
- 150000005846 sugar alcohols Chemical class 0.000 description 1
- 229920001864 tannin Polymers 0.000 description 1
- 239000001648 tannin Substances 0.000 description 1
- 235000018553 tannin Nutrition 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
- 229920003170 water-soluble synthetic polymer Polymers 0.000 description 1
Classifications
-
- 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
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- 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
-
- 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
-
- 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
- C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0421—Methods of deposition of the material involving vapour deposition
-
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
-
- 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
-
- 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
- H01M4/364—Composites as mixtures
-
- 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
-
- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
-
- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
-
- 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
-
- 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
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- 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
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/74—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by peak-intensities or a ratio thereof only
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/82—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by IR- or Raman-data
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/85—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by XPS, EDX or EDAX data
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/10—Solid density
-
- 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
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
-
- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Silicon Compounds (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The present invention addresses the problem of providing composite particles that can achieve both high silicon utilization and oxidation inhibition during water dispersion. The composite particles of the present invention are composite particles having a particle containing a carbon material and silicon, and a coating layer containing carbon and oxygen on the surface of the particle, and have a true density of 1.80 to 1.99g/cm 3 In the Raman spectrum, the peak exists between 450 and 495cm ‑1 If the intensity of the peak is I Si And the strength of the G band is set as I G Then I Si /I G In the X-ray photoelectron spectroscopy, the atomic number ratios of Si, O and C are set to be A Si 、A O And A C And SiO is combined with 2 And SiO are respectively set as B SiO2 、B SiO Then A Si Is above 0.05，I Si /I G And A C /(A C +A Si ×(B SiO2 +B SiO ) With a prescribed relationship.
Description
Technical Field
The present invention relates to composite particles, a method for producing the same, and use thereof.
Background
Lithium ion secondary batteries used in IT devices such as smart phones and tablet PCs, dust collectors, electric tools, electric bicycles, unmanned aerial vehicles, and automobiles require a negative electrode active material having both high capacity and high output. As the negative electrode active material, silicon (theoretical specific capacity: 4200 mAh/g) having a theoretical specific capacity higher than that of graphite (theoretical specific capacity: 372 mAh/g) currently used has been attracting attention.
However, silicon (Si) expands and contracts with electrochemical lithium intercalation and deintercalation, and the volume at the time of expansion is about 3 to 4 times as large as the volume at the time of contraction. As a result, silicon particles naturally collapse or separate from the electrode, and thus it is known that the cycle characteristics of lithium ion secondary batteries using silicon are significantly low. Accordingly, there has been an active study to use silicon in a structure in which the degree of expansion and contraction of the negative electrode active material as a whole is reduced, instead of merely replacing silicon with graphite. Among them, a large number of attempts have been made to complex carbonaceous materials.
As a high-capacity and long-life negative electrode active material, for example, patent document 1 discloses a silicon-carbon composite material (si—c composite material) obtained by a method in which porous carbon particles are brought into contact with a silane gas at a high temperature to thereby generate silicon in pores of porous carbon. Patent document 1 also discloses a material obtained by coating the si—c composite material with a carbon layer by a Chemical Vapor Deposition (CVD) method.
Prior art literature
Patent document 1: japanese patent application laid-open No. 2018-534720
Disclosure of Invention
Problems to be solved by the invention
Unlike carbon materials such as graphite, which have been conventionally used as negative electrode active materials, silicon is oxidized when it comes into contact with an oxidizing agent such as oxygen or water. When silicon containing silicon oxide formed by this oxidation is used as the negative electrode active material, the silicon oxide reacts with lithium to form lithium silicate. Lithium silicate becomes the cause of irreversible capacity. In general, the negative electrode active material is in contact with air or water when an electrode is produced. In addition, the negative electrode active material and the electrode using the negative electrode active material may be stored in air. Therefore, a negative electrode active material that suppresses oxidation of silicon is preferably used.
When a material obtained by carbon-coating a si—c composite material disclosed in patent document 1 by a CVD method is used as a negative electrode active material, according to the study of the present inventors, oxidation degradation can be suppressed, but silicon utilization efficiency and coulombic efficiency are reduced. The silicon utilization represents the ratio of the capacity per unit content of silicon in the anode active material to the theoretical specific capacity of silicon (4200 mAh/g). If the silicon utilization is low, more si—c composite material is required to increase the capacity, and therefore the silicon utilization is preferably as high as possible. Silicon utilization is thought to become low because: if the heat treatment temperature at the time of carbon coating is high, silicon in the si—c composite material reacts with carbon to produce silicon carbide. When the temperature at the time of film formation by CVD is reduced, the reduction in silicon utilization rate can be suppressed, but there is a concern that insufficient carbonization occurs and the resistance increases due to the coating layer thickness.
In the case where carbon coating is not performed, the reduction in silicon utilization rate can be avoided, but the oxidation described above cannot be suppressed. The si—c composite material can be used as a negative electrode active material of a lithium ion secondary battery, and as a method for producing a negative electrode, a method of applying an aqueous slurry containing a negative electrode active material to a current collector and drying the same is general. In the case of evaluating a battery in a laboratory, a small amount of aqueous slurry was prepared and an electrode was fabricated by coating for a relatively short time, so that the si—c composite material was hardly oxidized in water, and the adverse effect on the battery performance was small. However, in actual battery production, when an aqueous slurry is prepared in a large amount and a large-area electrode is coated, oxidation of the si—c composite material proceeds in the aqueous slurry, and for example, the degree of oxidation varies between the initial stage of coating and the end of coating, and there is a problem that the electrode capacity decreases at the end of coating. Further, since hydrogen is generated when oxidized in water, it is also conceivable that this hydrogen remains in the coating layer and becomes a cause of coating failure such as pinholes.
In the present invention, the object is: provided are composite particles which achieve high silicon utilization in a lithium ion secondary battery and which are capable of suppressing oxidation when a Si-C composite material is dispersed in water, i.e., composite particles which are composed of a Si-C composite material, achieve high silicon utilization in a lithium ion secondary battery, and are difficult to oxidize when dispersed in water.
Means for solving the problems
Patent document 1 does not discuss the quality of the carbon coating. Patent document 1 discloses an experimental example in which the capacity of the si—c composite material is suppressed from decreasing before and after carbon coating, with respect to carbon coating at 550 ℃, but the coating layer thickness is increased by 4.6% in weight, so that the resistance may be increased when forming a lithium ion secondary battery. In patent document 1, there is no description about the effect of oxidation inhibition at the time of water dispersion. In order to form a high-quality carbon layer in the sense of water and oxygen barrier properties, it is generally necessary to perform a carbon CVD method at a high temperature.
On the other hand, if carbon and silicon are exposed to high temperature in contact, silicon carbide (SiC) is considered to be generated. Since silicon carbide does not undergo lithium intercalation/deintercalation reaction, if the proportion of silicon carbide in the si—c composite material increases, the silicon utilization rate decreases.
The present inventors have studied a coating material and a coating method in order to obtain a coating layer of high quality by suppressing the generation of SiC. As a result, the present inventors have found novel composite particles that can improve silicon utilization and suppress oxidation during water dispersion by providing a thin coating layer containing carbon and oxygen on the surface of a si—c composite material, and completed the present invention.
That is, the present invention is constituted by the following structure, for example.
〔1〕
A composite particle, comprising: particles comprising a carbon material and silicon, and a coating comprising carbon and oxygen on the surface of the particles,
the true density obtained by measuring the dry density using helium was 1.80g/cm 3 Above and 1.99g/cm 3 In the following the procedure is described,
in the raman spectrum of the complex particles,
the peak exists between 450 and 495cm -1 ，
If the intensity of the peak is set as I Si And the strength of the G band (1580 cm) -1 Peak intensity in the vicinity) is set to I G Then I Si /I G Is not more than 1.3 of the total weight of the composition,
if the atomic number ratios of Si, O and C based on the narrow spectrum of the X-ray photoelectron spectroscopy of the composite particles are respectively set as A Si 、A O And A C And analyzing the Si species ratio obtained by Si2p energy spectrum state analysis 2 And SiO are respectively set as B SiO2 、B SiO ，
Then A Si Is not less than 0.05 percent,
the complex particles satisfy at least one of the following formulas (1) and (2):
Y≥0.75 (1)
Y≥－0.32X+0.81 (2)
[ in the formulae (1) and (2), x=i Si /I G ，Y＝A C /(A C +A Si ×(B SiO2 +B SiO ))]。
〔2〕
The composite particles according to the above [ 1 ],
the I is Si /I G Is 0.64 or less, and satisfies the formula (1).
〔3〕
According to the composite particles of [ 1 ] or [ 2 ],
the carbon material is porous carbon, and silicon is contained in at least some of the pores of the porous carbon.
〔4〕
The composite particles according to any one of the above [ 1 ] to [ 3 ],
the thickness of the coating layer was so thin that it was not substantially measured when the cross-sectional view was performed by an electron microscope.
〔5〕
The composite particles according to any one of the above [ 1 ] to [ 4 ],
in an XRD pattern obtained by powder XRD using Cu-K alpha rays, the half width of a peak on the Si (111) plane is 3.0 DEG or more, the ratio of the peak intensity on the SiC (111) plane to the peak intensity on the Si (111) plane is 0.01 or less, and the R value of the Raman spectrum is 0.26 or more and less than 1.34.
〔6〕
The composite particles according to any one of the above [ 1 ] to [ 5 ],
is hydrophobic.
〔7〕
The composite particles according to any one of the above [ 1 ] to [ 6 ],
substantially no graphite is contained within the composite particles.
〔8〕
The composite particles according to any one of the above [ 1 ] to [ 7 ],
50% particle size D in volume-based cumulative particle size distribution V50 1.0 to 30.0 mu m.
〔9〕
The composite particles according to any one of the above [ 1 ] to [ 8 ],
the silicon content is 30 to 80 mass% and the oxygen content is 4.0 mass% inclusive.
〔10〕
A method for producing composite particles, comprising:
a step (A) of bringing a silicon-containing gas into contact with porous carbon to deposit silicon into pores and surfaces of a carbon material, thereby obtaining Si/C particles;
a step (B) of bringing a gas containing a hydrocarbon having an unsaturated bond into contact with the Si/C particles at 400 ℃ or lower; and
and (C) oxidizing the hydrocarbon-containing layer obtained in the step (B).
〔11〕
According to the method for producing a composite particle of [ 10 ],
the step (a) and the step (B) are performed continuously.
〔12〕
According to the method for producing a composite particle of [ 10 ] or [ 11 ],
manufacturing the composite particles of any one of [ 1 ] to [ 9 ].
〔13〕
A polymer-coated composite particle comprising a polymer-coated composite particle,
at least a part of the surface of the composite particles of [ 1 ] to [ 9 ] is provided with an inorganic particle-containing polymer component coating layer containing 1 or more kinds of inorganic particles selected from the group consisting of graphite and carbon black and a polymer component, and the content of the polymer component is 0.1 to 10.0 mass%.
〔14〕
A negative electrode active material, which comprises a negative electrode active material,
comprising said [1] to [ 9 ] or said [ 13 ] polymer-coated composite particles.
〔15〕
A negative electrode mixture layer, which is prepared from a negative electrode material,
comprising the negative electrode active material of [ 14 ].
〔16〕
A lithium ion secondary battery, which comprises a battery cell,
and a negative electrode mixture layer comprising the above [ 15 ].
Effects of the invention
According to the present invention, it is possible to provide composite particles which have high silicon utilization and are hardly oxidized when water is dispersed, a negative electrode active material for a lithium ion secondary battery using the composite particles, and a lithium ion secondary battery.
Detailed Description
The present invention will be specifically described below. Unless otherwise specified, the "lithium ion secondary battery" may be simply referred to as a "battery".
[1] Composite particles
The composite particles according to the present invention comprise: particles comprising a carbon material and silicon, and composite particles comprising a coating of carbon and oxygen on the surface of the particles. That is, the composite particles according to the present invention are particles having a coating layer containing carbon and oxygen on the surface and having a particle-like substance containing a carbon material and silicon on the inner side of the coating layer.
The term "particulate matter containing a carbon material and silicon" (hereinafter also referred to as "Si/C particles") refers to particulate matter containing silicon (Si) on the surface and inside of the carbon material. The carbon material is preferably porous carbon, and preferably silicon is contained in at least pores of the porous carbon. The term "porous carbon" refers to carbon having fine pores. Preferably, fine Si domains are uniformly formed in the carbon material. "Si domains" refer to regions where silicon is present. Since the Si/C particles have such a structure, expansion and contraction associated with charge and discharge isotropically occur, and thus the charge and discharge cycle durability is improved. This structure can be determined by observing the cross-section SEM-EDS of the composite particles. If the silicon and carbon distributions overlap in the composite particles, it is known that fine Si domains having a spatial resolution equal to or less than SEM-EDS are uniformly dispersed.
The Si/C particles can be produced by reacting, for example, silane (SiH 4 ) The silicon source is obtained by bringing a particulate porous carbon into contact with the silicon source to precipitate silicon (usually in an amorphous form) in pores in the porous carbon. In this case, by using porous carbon having fine pores, fine Si domains can be uniformly formed in the particles.
The composite particles according to the present invention have a peak in raman spectrum at least at raman shift=450 to 495cm -1 、1350cm -1 Nearby, 1580cm -1 Nearby. Typically, silicon wafers, particulate silicon, thermally treated SiO x Isocrystalline silicon at 520cm -1 Peaks appear nearby. Amorphous silicon has peaks at lower raman shifts than it, and therefore, at 450 to 495cm -1 In the presence of peaks, representing the complexThe composite particles have amorphous silicon. If the silicon is amorphous, expansion and contraction during charge and discharge proceed relatively isotropically, so that cycle characteristics can be improved.
450-495 cm of the mixture -1 The peak intensity at the point is set to I si And the strength of the G band (1580 cm) -1 Peak intensity in the vicinity) is set to I G Ratio I at time si /I G It is 1.3 or less, preferably 0.94 or less, more preferably 0.64 or less, and most preferably 0.54 or less.
The raman spectrum shows a peak of silicon, which indicates the presence of silicon in the surface of the composite particles and/or in the pores near the surface of the Si/C particles. It is known that: in XPS described later, information is obtained from the surface of a substance to a depth of several nm, but in raman spectroscopy, information is obtained from the surface of a carbon material to a depth of about 1 μm to submicron (hereinafter, the position of information obtained by raman spectroscopy is also referred to as "near the surface").
I of Complex particles Si /I G A value of 1.3 or less indicates that the surface of the Si/C particles is not covered with a silicon-containing component, and indicates that the structure contains silicon and carbon. On the other hand, in the case of very high silicon proportions, I Si /I G The value is very large compared with the above range. Through I Si /I G Within the above range, expansion and contraction of the surface of the Si/C particles occur to the same extent as the interior of the Si/C particles during charge and discharge, and concentration of stress of expansion and contraction on the surface of the Si/C particles can be avoided, thereby improving cycle characteristics.
I Si /I G The lower limit of (2) is preferably 0.01. More preferably 0.02. If the thickness is less than 0.01, the thickness of the coating layer becomes large, which becomes a factor of the increase in resistance.
The "peak intensity" is a height from the base line to the peak top point after the correction of the base line.
I Si /I G The value of (a) can be changed by adjusting the reaction conditions (gas composition ratio, gas flow rate, temperature program, reaction time) of step (a) in the method for producing composite particles described later.
In the composite particles according to the embodiment of the present invention, the half width of the peak of the Si (111) plane is preferably 3.0 ° or more in the XRD pattern obtained by powder X-ray diffraction measurement (powder XRD) using cu—kα rays. The half width of 3.0 ° or more means that the crystallite size of silicon in the composite particles is small, which can suppress the destruction of silicon accompanying charge and discharge. From the same viewpoint, the half width is preferably 4.0 ° or more, more preferably 5.0 ° or more. The half-width is preferably 10.0 ° or less, and more preferably 8.0 ° or less. The peak on the Si (111) plane means a peak derived from Si and occurring near 28 ° 2θ. The "peak intensity" at the time of obtaining the half-peak width is set to be the height from the base line to the peak top point after the correction of the base line.
The composite particles according to an embodiment of the present invention have a D-band intensity (1350 cm) -1 Peak intensity in the vicinity) is set to I D Intensity I with G band at the time G The ratio, R value (I D /I G ) Preferably 0.26 or more and less than 1.34. When the R value is 0.26 or more, the reaction resistance of the negative electrode using the composite particles is sufficiently low, and thus the coulombic efficiency of the battery is improved. On the other hand, an R value of less than 1.34 means fewer defects in the carbon material. By the R value being less than 1.34, the internal resistance of the battery decreases and the rate characteristics improve. From the same viewpoint, the R value is more preferably 0.45 or more, and still more preferably 0.65 or more. The R value is more preferably 1.30 or less, and still more preferably 1.20 or less.
The composite particles according to the present invention have a coating layer containing carbon and oxygen on the surface. The structure of the composite particles has the following characteristics.
If the atomic number ratios of Si, O and C based on narrow spectrum of X-ray photoelectron spectroscopy (XPS: X-ray PhotoelectronSpectroscopy) of the composite particles are respectively set as A Si 、A O And A C And analyzing the Si species ratio obtained by Si2p energy spectrum state analysis 2 And SiO is set as B SiO2 、B SiO ，
Then A Si Is 0.05 or more and satisfies at least one of the following formulas (1) and (2) And then the other is a member.
Y≥0.75(1)
Y≥－0.32X+0.81(2)
[ in the formulae (1) and (2), X=I Si /I G ，Y＝A C /(A C +A Si ×(B SiO2 +B SiO ))〕
In addition, A Si +A O +A C ＝1.00。
It is known that: XPS is a technique for obtaining knowledge about the types, amounts of existence, and chemical bond states of elements present on the surface of a substance, and is a technique for obtaining information from the surface of a substance to a depth of several nm.
<1>A Si
A Si Less than 0.05 means that the coating is too thick. If the coating layer is too thick, the electrical resistance of the composite particles increases. A is that Si Preferably 0.15 or more, and more preferably 0.25 or more. XPS has an analysis depth of several nm and is very shallow, so Si is observable to some extent meaning that the coating is an extremely thin layer.
The coating contains carbon and oxygen and is therefore electronically conductive compared to carbon coatings. If the coating is too thick, the resistance increases, so a thin layer is required.
<2>A C /(A C +A Si ×(B SiO2 +B SiO ))
A C /(A C +A Si ×(B SiO2 +B SiO ) The value of (c) is an index of the carbon concentration at a position (depth of spatial resolution in XPS) from the surface to several nm in depth of the composite particle. This is because it is thought that Si is represented by SiO at the surface of the composite particles 2 In the form of oxides such as SiO, it is believed that the majority of the composite particle surface is formed from carbon and SiO 2 Silicon oxide such as SiO. However, at A C Since information about carbon in Si/C particles is included not only on the surface but also on the surface, the index does not reflect only the carbon concentration of the coating layer.
A C /(A C +A Si ×(B SiO2 +B SiO ) A small value indicates a low carbon concentration on the surface of the composite particles. If the carbon isThe concentration becomes lower, and the oxidation suppressing ability decreases. That is, the composite particles are easily oxidized.
However, as the silicon concentration near the surface of the composite particles becomes higher, the oxidation inhibition ability is fully exhibited even if the carbon concentration on the surface of the composite particles becomes lower. This is thought to be because as the silicon concentration near the surface of the composite particles becomes higher, i.e., as I Si /I G The silicon that may be oxidized becomes difficult to oxidize due to the presence of the complex of carbon derived from hydrocarbon and silicon oxide. Namely, from A C /(A C +A Si ×(B SiO2 +B SiO ) The index of the carbon concentration represented by the above-mentioned formula (i) is affected by the silicon concentration in the vicinity of the surface of the composite particles.
Accordingly, the composite particles according to the present invention satisfy the following formula (1).
Y≥0.75 (1)
[ in formula (1), Y=A C /(A C +A Si ×(B SiO2 +B SiO ))〕。
However, when the silicon concentration in the vicinity of the surface of the composite particle is relatively high (specifically, in I Si /I G If the ratio exceeds 0.2), the following expression (2) may be satisfied, or the expression (1) may not be satisfied.
Y≥－0.32X+0.81 (2)
[ in formula (2), X=I Si /I G ，Y＝A C /(A C +A Si ×(B SiO2 +B SiO ))〕
When the above formulas (1) and (2) are not satisfied, the oxidation inhibition ability of the composite particles becomes low.
Y is A C /(A C +A Si ×(B SiO2 +B SiO ) Preferably 0.85 or more.
Y is A C /(A C +A Si ×(B SiO2 +B SiO ) Preferably 0.98 or less.
Although the structure of the coating layer cannot be determined, a thin film layer obtained by compositing surface carbon and silicon oxide is preferable.
A C /(A C +A Si ×(B SiO2 +B SiO ) For example, the reaction temperature, reaction time, reaction pressure, or hydrocarbon type or concentration in the step (B) can be adjusted in the method for producing composite particles described later.
The coating preferably comprises a compound derived from a hydrocarbon. The coating layer contains a hydrocarbon-derived compound, and can be measured by thermally decomposing GC-MC of the composite particles, and can be determined from the fact that the hydrocarbon-derived compound is contained in the gas generated from the composite particles at 200 to 600 ℃.
The coating layer can be produced by bringing a carbon source having an unsaturated bond into contact with Si/C particles at a low temperature, and then oxidizing the resultant substance. Details will be described later.
In the composite particles according to an embodiment of the present invention, the coating layer is preferably thin to such an extent that it is substantially undetectable in cross-sectional observation by an electron microscope. If the coating is thin as described above, the composite particles have low electrical resistance. Scanning Electron Microscopy (SEM) does not have a resolution to the extent that it can discriminate a few nm thickness, and therefore it is impossible to measure the thickness of a thinner coating. Although Transmission Electron Microscopy (TEM) is sufficient in resolution and can observe even a thickness of several nm, when a sample for TEM observation of a thin film including a coating layer is prepared from composite particles, the coating layer of the composite particles is damaged and destroyed by processing, and therefore the thickness of the coating layer cannot be observed with TEM in practice. "substantially undetectable" refers to such a state. However, even in the case of a film which is not substantially measurable in cross-sectional observation by an electron microscope, the presence of a coating layer can be confirmed by XPS described above or a test of hydrophobicity of the surface described later.
The true density of the composite particles according to the invention is 1.80g/cm 3 The above. This value was calculated by measuring dry density using helium gas.
True density less than 1.80g/cm 3 This means that the amount of silicon to be filled into the pores of carbon in the composite particles is small, and the coating layer is a thick layer of low-density organic matter such as tar component and polymer.
If the true density is 1.80g/cm 3 As described above, the amount of silicon filled into the pores of the carbon in the composite particles is sufficient, and the coating layer is thin, so that the specific capacity of the composite particles can be increased and/or the electrical resistance can be reduced. From the same point of view, the true density is preferably 1.85g/cm 3 The above is more preferably 1.88g/cm 3 The above.
The true density of the composite particles according to the invention is 1.99g/cm 3 The following is given. If the true density is 1.99g/cm 3 Hereinafter, the carbon material in the composite particles is amorphous, and the substance of the carbon material is more isotropic. Since the true density is lower than the literature values of the densities of carbon and silicon, it is considered that voids exist in the composite particles, into which helium gas cannot intrude from the outside of the particles, and therefore, if the true density is within the above range, the cycle characteristics can be improved. In addition, since the amount of silicon carbide in the composite particles is small, a decrease in silicon utilization rate can be suppressed. Silicon carbide has a higher density than carbon or Si, and therefore, if silicon carbide is contained in the composite particles, the true density increases. From this point of view, the true density is preferably 1.98/cm 3 Hereinafter, more preferably 1.96g/cm 3 The following is given.
The true density obtained by the dry density measurement can be measured by a gas phase displacement method. The gas phase displacement method is as follows: in an environment maintained at a constant temperature, a sample and helium gas are charged into a container whose volume is measured in advance by helium gas, and the true density is calculated from the volume of helium gas excluded from the sample and the mass of the sample. As a device for the vapor phase substitution method, for example, accuPyc (registered trademark) II 1340Gas Pycnometer manufactured by micromeritics corporation can be used.
In the composite particles according to the embodiment of the present invention, in the XRD pattern obtained by powder X-ray diffraction measurement (powder XRD) using cu—kα rays, the (peak intensity of SiC (111) plane)/(the peak intensity of Si (111) plane) is preferably 0.01 or less. As a result, siC (silicon carbide) is not contained in the composite particles or the SiC content is extremely low, and therefore, the utilization ratio of silicon as a battery active material improves, and the initial discharge capacity can be improved. The (peak intensity of SiC (111) plane)/(peak intensity of Si (111) plane) is also denoted as I SiC(111) /I Si(111) 。I SiC(111) /I Si(111) The lower limit of (2) is more preferably 0.00, that is, the peak intensity of the SiC (111) plane is more preferably not observed. The peak on the SiC (111) plane is a peak derived from SiC and appearing near 35 ° in 2θ. The peak on the Si (111) plane is a peak derived from Si and occurring near 28 ° 2θ.
The composite particles according to one embodiment of the present invention are preferably hydrophobic. If hydrophobic, the water-protecting effect is improved. The negative electrode mixture layer contains a polymer that becomes a binder. Since the polymer has a good affinity for hydrophobic particles, it can be dispersed more uniformly in the production of a slurry for negative electrode coating.
The hydrophobic composite particles can be produced, for example, by using a hydrocarbon having an unsaturated bond in the step (B) described later.
Examples of the method for measuring the hydrophobicity include a method for measuring the contact angle of water with respect to the composite particles, such as measuring the contact angle of water after forming the composite particles into pellets, a method for measuring the adsorption amount of water vapor with respect to the composite particles and dividing the same by the nitrogen adsorption amount of the composite particles, and a BET specific surface area obtained by the nitrogen adsorption method.
As a method for measuring the hydrophobicity, a method for observing the penetration behavior of water into powder is easy and simple to judge. This measurement can be performed by the method described in examples, for example.
The composite particles according to an embodiment of the present invention preferably do not contain graphite in the composite particles. The presence of graphite in the composite particles was determined by XRD pattern obtained by powder X-ray diffraction measurement (powder XRD) using Cu-K alpha rays. In the case where graphite is present in the composite particles in a meaningful manner, a sharp peak around 26 ° in 2θ derived from graphite can be observed. In this vicinity, halos derived from carbon and silicon oxide are observed at the same time, but these patterns have low intensities, and on the other hand, graphite is observed as a very sharp peak having high intensity, and therefore, when no peak of graphite is observed, it is considered that graphite is not substantially contained in the composite particles.
It is difficult to obtain porous graphite, and it is also difficult to distribute uniform fine pores in graphite particles. The composite particles of the present invention preferably have fine Si domains uniformly formed in the particles. When graphite is contained in the composite particles, expansion and contraction during charge and discharge become nonuniform in the particles, and cycle characteristics are degraded.
As described above, since expansion and contraction during charge and discharge are preferably uniform in the particles, the shape of the composite particles according to an embodiment of the present invention is preferably 1.25 or less in average aspect ratio, and more preferably has no corners in a part of the particles. The composite particles are further preferably spherical (the composite particles have a circular cross section). The aspect ratio is a value obtained by dividing the long diameter of a particle by the short diameter. An aspect ratio of 1.00 means that the long and short diameters are equal, so that the closer the average aspect ratio is to 1.00, the more preferable.
The degree of sphericity can be determined from the average circularity calculated from the cross-sectional shape. The average circularity is preferably 0.95 to 1.00. The circularity is expressed by the following equation.
(circularity) =4pi× (S/L) 2 )
Here, S is the particle cross-sectional area [ m ] 2 ]L is the particle circumference [ m ]]。
The average aspect ratio and the average circularity can be calculated by analyzing an image obtained by a Scanning Electron Microscope (SEM) with image analysis software. Analysis was performed on 100 composite particles randomly selected in the SEM photograph, and the average value (number average value) of 100 particles was used for determination. Examples of the Image analysis software include Image J.
The composite particles according to one embodiment of the present invention preferably have a BET specific surface area of 0.1m 2 And/g. By BET specific surface area of 0.1m 2 And/g or more, the viscosity of the slurry at the time of electrode production can be made appropriate, and a good electrode can be produced. From the same viewpoint, the BET specific surface area is more preferably 0.5m 2 Preferably at least 0.9m 2 And/g.
The composite particles according to one embodiment of the present invention preferably have a BET specific surface area of 100.0m 2 And/g or less. By 100.0m 2 /g toIn addition, side reactions with the electrolyte can be reduced. From the same viewpoint, the BET specific surface area is more preferably 50.0m 2 Preferably less than or equal to/g, more preferably 25.0m 2 And/g or less.
The BET specific surface area is usually calculated by the BET method from adsorption isotherms measured by a dedicated measuring device known in the art. As the adsorption gas, nitrogen is generally used.
The composite particles according to an embodiment of the present invention preferably have a 50% particle diameter D in the cumulative particle size distribution on a volume basis V50 Is 1.0 μm or more. Because through D V50 When the particle size is 1.0 μm or more, side reactions with the electrolyte can be reduced. Further, the powder is excellent in handleability, a slurry having a viscosity and a density suitable for coating is easily prepared, and the density when formed into an electrode is easily increased. From this point of view, D V50 More preferably 2.0 μm or more, still more preferably 3.0 μm or more, and most preferably 3.5 μm or more.
The composite particles according to an embodiment of the present invention are preferably the aforementioned D V50 Is 30.0 μm or less. Through D V50 Since the diffusion length of lithium in each particle is reduced to 30.0 μm or less, streaks and abnormal irregularities are not generated when the lithium ion battery is applied as a slurry to a current collector, in addition to the excellent rate characteristics of the lithium ion battery. From this point of view, D V50 More preferably 20.0 μm or less, and still more preferably 15.0 μm or less.
The composite particles according to an embodiment of the present invention preferably have a 90% particle diameter D in the cumulative particle size distribution on a volume basis V90 Is 50.0 μm or less. Through D V90 Since the diffusion length of lithium in each particle is 50.0 μm or less, streaks and abnormal irregularities are not generated when the lithium ion battery is applied as a slurry to a current collector, in addition to the excellent rate characteristics of the lithium ion battery. From this point of view, D V90 More preferably 40.0 μm or less, still more preferably 30.0 μm or less, and most preferably 20.0 μm or less.
These volume-based cumulative particle size distributions are measured, for example, by a laser diffraction particle size distribution meter.
The composite particles according to an embodiment of the present invention preferably have a silicon content of 30 mass% or more. The "silicon content" of the composite particles herein refers to the content of elemental silicon and compounds contained in the composite particles as silicon elements. When the silicon content is 30 mass% or more, the amount of silicon in the composite particles is sufficient, and the discharge capacity can be improved. From the same viewpoint, the silicon content is more preferably 35% by mass or more, and still more preferably 40% by mass or more.
The composite particles according to an embodiment of the present invention preferably have a silicon content of 80 mass% or less. If the amount is 80 mass% or less, the amount of silicon in the composite particles is not excessive, and therefore, the volume change due to expansion and contraction thereof can be absorbed by carbon. From the same viewpoint, the silicon content is more preferably 75 mass% or less, and still more preferably 70 mass% or less.
The silicon content in the composite particles can be obtained by performing fluorescent X-ray analysis measurement and analysis using a basic parameter method (FP method) or the like. Further, the composite particles may be burned to remove carbon, and the remaining ash after combustion may be completely dissolved in an acid or alkali, and then quantified by inductively coupled plasma atomic emission spectrometry (ICP-AES).
The composite particles according to an embodiment of the present invention preferably have an oxygen content of 4.0 mass% or less. When the oxygen content is 4.0 mass% or less, the irreversible capacity of the negative electrode of the lithium ion secondary battery can be reduced. From the same viewpoint, the oxygen content is more preferably 2.0 mass% or less, and still more preferably 1.0 mass% or less. The lower limit of the oxygen content is preferably 0.2 mass%. When the oxygen content is 0.2 mass% or more, a high oxidation inhibition ability is exhibited.
The oxygen content in the composite particles can be measured by an oxygen-nitrogen simultaneous measurement device, for example.
In the present invention, unless otherwise specified, the oxygen content of the composite particles means the oxygen content of the composite particles stored within 2 days after production or in a non-oxidizing atmosphere. When measurement is impossible within 2 days after production due to a process or the like, the measurement is considered to be equivalent to within 2 days after production even if the measurement is performed later by storing the sample in an inert atmosphere such as argon. This is because oxidation does not progress in the case of storage under an inert atmosphere.
[2] Method for producing composite particles
The method for producing composite particles according to the present invention includes the following steps (a), (B) and (C). The composite particles of the present invention, that is, the composite particles described in [1], can be obtained by the method for producing composite particles of the present invention.
Step (A): a step of bringing a silicon-containing gas into contact with (i.e., reacting with) porous carbon to deposit silicon into and on the pores of the porous carbon, thereby obtaining Si/C particles
Step (B): a step of bringing a gas containing a hydrocarbon having an unsaturated bond into contact with the Si/C particles at 400 ℃ or lower
Step (C): oxidizing the material obtained in the step (B)
In the present specification, a carbon material having fine pores is referred to as "porous carbon". The composite particles preferably have a structure in which silicon is contained in the particles, and therefore, the porous carbon preferably has a pore volume capable of supporting silicon therein. In addition, in the nitrogen adsorption test of the carbon material (porous carbon), the relative pressure P/P was measured 0 The pore volume at 0.99 is set to V 0.99 V at the time of 0.99 More preferably from 0.25cc/g to 1.50 cc/g.
Further, silicon is preferably contained in the composite particles as fine domains, and thus, it is more preferable that fine pores in the porous carbon are large. Specifically, the relative pressure P/P in the nitrogen adsorption test of porous carbon 0 The pore volume at 0.01 is set to V 0.01 V at the time of 0.01 /V 0.99 More preferably 0.45 or more, and most preferably 0.55 or more. The nitrogen adsorption test can be performed by a known method.
As the porous carbon, for example, activated carbon fiber, molecular sieve carbon, or inorganic template carbon can be used. In addition, porous carbon obtained by activating hard carbon with steam or carbon dioxide can be used. Preferably, porous carbon satisfying the above conditions is used. The activated carbon fibers may be pulverized granular activated carbon fibers, or may be pulverized to form particles after supporting silicon.
The hard carbon can be obtained, for example, by heat-treating a phenolic resin in an inert atmosphere at 600 to 1400 ℃, preferably at 800 to 1400 ℃.
The step (a) is preferably performed after the porous carbon is adjusted to a desired shape or particle size distribution of the composite particles. This is because the shape and particle size of the particles hardly change in the steps (a), (B) and (C), and thus the shape and particle size distribution of the composite particles are the same as those of the porous carbon. Thus, the porous carbon used in the step (a) may be crushed, pulverized, and sieved.
After the composite particles are produced through the steps (a), (B) and (C), the particles may aggregate with each other. In this case, it is preferable to crush the porous carbon to recover the shape and particle size distribution of the raw material. However, when excessive energy is applied at this time and the composite particles are crushed to change the particle shape, the portion where no coating layer is formed on the surface of the composite particles increases, and the oxidation inhibition ability becomes low, which is undesirable.
The porous carbon is preferably spherical. The spherical porous carbon is more preferably obtained by carbonizing and activating a spherical phenolic resin. In addition, in the spherical porous carbon, the spherical shape can be maintained without the pulverization step, and is further preferable.
As the silicon-containing gas, a silane gas can be preferably used. The silane gas may be used in combination with an inert gas such as helium or argon or a reducing gas such as hydrogen.
The step (a) is a step of: the porous carbon is placed in a reactor, and a silicon-containing gas is brought into contact with the porous carbon to deposit silicon into pores and surfaces of the porous carbon, thereby obtaining Si/C particles.
The morphology of the reactor is not limited. As the reactor, a continuous furnace such as a stationary furnace, a fluidized bed furnace, a rotary kiln, a furnace having a stirring function for powder, a roller kiln, or a pusher furnace can be used.
The reaction temperature is not limited as long as it is a temperature at which silicon-containing gas such as silane gas is decomposed and silicon is deposited in pores of porous carbon, but is preferably 300 ℃ to 450 ℃. If the temperature is lower than 300 ℃, the decomposition of the silane gas does not sufficiently occur, and thus the precipitation of silicon becomes insufficient. If the temperature exceeds 450 ℃, the silicon is significantly deposited on the surface of the porous carbon (including the opening portions of the pores) as compared with the silicon deposited in the pores due to the generation of the decomposition of the silane gas in the pores of the porous carbon, and the opening portions of the pores are blocked by the deposited silicon, so that the deposition in the pores becomes insufficient.
Even at 450 ℃ or lower, decomposition of silane occurs on the surface of porous carbon, and silicon is precipitated. In general, since the surface area of the pores of the porous carbon is much larger than the surface area of the outside, silicon deposited in the pores of the porous carbon increases overwhelmingly. When silicon is present in the pores of the porous carbon, the composite particles are preferable because the durability against stress into the composite particles due to expansion and contraction of silicon associated with charge and discharge of the battery is higher than that of the composite particles present on the outer surface of the porous carbon. In the treatment at a higher temperature, precipitation at the surface of the porous carbon becomes remarkable, and the number of sites where the openings of the pores are blocked increases.
Conditions such as gas composition ratio, gas flow rate, and temperature program are appropriately adjusted while observing the properties of the composite particles.
The step (B) is a step of: the Si/C particles obtained in the step (A) are placed in a reactor, and a gas containing a hydrocarbon having an unsaturated bond is brought into contact with the Si/C particles at 400 ℃ or lower. The composite particles according to the present invention are thin in coating. Methods such as carbon CVD that deposit carbon onto a surface can form thick carbon coatings and are therefore unsuitable. The si—h group on the surface of the Si/C particle is preferably reacted with a hydrocarbon having an unsaturated bond to form a hydrocarbon-containing layer on the surface of the Si/C particle. The hydrocarbon-containing layer may contain a substance obtained by reacting hydrocarbons with each other. As the gas of the hydrocarbon having an unsaturated bond, a gas of a hydrocarbon having a double bond or a triple bond can be used. In the case where the hydrocarbon is a compound having a low vapor pressure and not gasifying at normal pressure, the hydrocarbon may be used at a pressure lower than normal pressure. Acetylene, ethylene, propylene and 1, 3-butadiene which are gases at normal pressure are preferable, and acetylene and ethylene are more preferable. In this case, various hydrocarbons may be used. In addition, inert gas such as helium or argon, or reducing gas such as hydrogen may be used in combination.
In the step (B), a treatment at a low temperature of 400℃or lower is required to react Si-H groups with unsaturated bonds. If the temperature exceeds this temperature, the amount of Si-H groups to be decomposed increases, and the targeted reaction, that is, the reaction of Si-H groups on the surface of Si/C particles with unsaturated bonds of hydrocarbons becomes less likely to occur. Further, since the reactivity of silicon in Si/C particles is very high, the reaction between porous carbon and silicon occurs at a high temperature exceeding 400 ℃ to produce silicon carbide, and the capacity of silicon decreases.
The lower limit of the reaction temperature is not limited as long as it is a temperature at which a hydrocarbon having an unsaturated bond reacts on the surface of the Si/C particle, and if the reaction temperature is low, the reaction rate is low, and therefore, it is preferably 100 ℃ or higher, more preferably 150 ℃ or higher.
The thickness of the hydrocarbon-containing layer may be a thickness corresponding to a molecular layer of hydrocarbon or a thickness corresponding to a few molecular layers. In addition, a portion of the hydrocarbons may also be decomposed. Even if a part of the hydrocarbon is decomposed into carbon, the hydrocarbon-containing layer is a material having high electrical resistance unlike the carbon coating, and therefore, a thin film is preferable. Therefore, the weight change before and after the step (B) is preferably small. The amount of increase in the mass of the Si/C particles having the hydrocarbon-containing layer obtained in the step (B) relative to the mass of the Si/C particles before the step (B) is more preferably 1.0 mass% or less, and still more preferably 0.5 mass% or less.
The step (C) is a step of oxidizing the substance obtained in the step (B). The step (C) is a step of introducing oxygen into the coating layer (to be precise, the hydrocarbon-containing layer formed on the surface of the Si/C particles in the step (B)). Although the structure of the coating is not quite clear, by including oxygen in the coating, the oxidation suppressing ability improves and the resistance becomes low. Oxidation can be carried out by contacting the coating with a gas containing oxygen (more specifically, an oxidizing gas). The oxygen-containing gas preferably has an oxygen concentration of 1 to 25% by volume, more preferably 1 to 20% by volume, still more preferably 5 to 20% by volume. In this case, oxygen is diluted with argon and nitrogen. Air may be used as the oxygen-containing gas, but for stable oxidation, it is preferable to adjust the humidity of air and keep it constant.
The reaction temperature, even when the coating layer is in contact with a gas containing oxygen, is preferably not less than room temperature and not more than 200 ℃. If it exceeds 200 ℃, the coating layer is decomposed or oxidized more than necessary, and thus, it is not preferable.
The reaction time, i.e. the time during which the coating is contacted with the oxygen-containing gas, is for example 0.1 to 120 hours.
The step (C) may be an oxidation treatment by changing the oxygen concentration.
The heat treatment is preferably carried out under an inert atmosphere or under low pressure after contacting the coating with a gas comprising oxygen. The temperature during the heat treatment is preferably 400℃or lower. It is considered that oxygen recombination into a coating layer can be stably performed by performing a heat treatment at 400 ℃ or lower to decompose and convert unreacted si—h groups into silicon. The heat treatment time is, for example, 0.1 to 100 hours.
The step (a) and the step (B) are preferably performed continuously. Since the silicon on the surface of the Si/C particles obtained in the step (A) has high activity, oxidation proceeds when the particles are in contact with the atmosphere, and Si-H groups on the surface are reduced. Therefore, the steps (a) and (B) are preferably performed continuously without being in contact with the atmosphere (air). The time between the step (a) and the step (B) is not limited as long as the Si/C particles are not in contact with the atmosphere. For example, the step (B) may be performed after the step (a) is stored under an inert atmosphere. In addition, as long as the Si/C particles obtained in the step (a) are not in contact with the atmosphere, separate apparatuses may be used for the step (a) and the step (B).
The step (B) and the step (C) may be performed by separate apparatuses. The steps (B) and (C) may be performed a plurality of times. For example, a method in which the step (C) is performed followed by the step (B), or a method in which the step (C) is performed followed by the step (B) is used.
[3] Composite particles also having a surface coating
The composite particles according to the present invention may have a layer further outside the composite particles having the Si/C particles and the coating layer on the surface of the Si/C particles (hereinafter also referred to as "composite particle body"). In order to distinguish it from the "coating layer" appearing in the foregoing, a layer disposed further outside the composite particle body is referred to herein as a "surface coating layer".
As a method for forming the surface coating layer, a method of forming a layer on at least a part of the surface of the composite particle, specifically, carbon coating, inorganic oxide coating, or polymer coating, is exemplified. Examples of the carbon coating method include Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). Examples of the method for coating the inorganic oxide include Chemical Vapor Deposition (CVD), physical Vapor Deposition (PVD), atomic Layer Deposition (ALD), and wet method. Wet methods include methods of applying a liquid in which a precursor of an inorganic oxide is dissolved and/or dispersed in a solvent to a composite particle body, and removing the solvent by heat treatment or the like. As the kind of polymer coating, there may be mentioned a method of coating with a polymer solution, a method of coating with a polymer precursor containing a monomer and polymerizing by the action of temperature, light or the like, or a combination thereof.
The surface coating of the composite particles can be analyzed by performing a surface analysis of the composite particles. Examples of the surface analysis include SEM-EDS, auger electron spectroscopy, XPS, microscopic infrared spectroscopy, and microscopic Raman spectroscopy.
In order to prevent silicon contained in the composite particles from reacting with carbon to form silicon carbide when forming the surface coating layer, it is preferable to use a method in which the temperature is raised to below 500 ℃ at the time of coating or energy is applied to the composite particle body by PVD, ALD, or the like for a short time without raising the temperature of the composite particle body for a long period of time.
As the composite particles further having a surface coating layer, the following polymer-coated composite particles are preferable. That is, the polymer-coated composite particles have, as the surface coating layer, at least a part of the surface of the composite particle body, an inorganic particle-containing polymer component coating layer containing 1 or more kinds of inorganic particles selected from graphite and carbon black and a polymer component, and the content of the polymer component is 0.1 to 10.0 mass%.
The polymer coated composite particles are preferably produced by a wet process. Specifically, the method comprises mixing inorganic particles composed of 1 or more kinds selected from graphite and carbon black, a polymer component and composite particles in a solvent, and drying the mixture to remove the solvent.
In this case, the liquid in which the components are dissolved or dispersed may be prepared in advance and then mixed. The inorganic particles are preferably smaller than the composite particle body, and therefore, a liquid in which the inorganic particles are dispersed in advance is preferably used. In the case of preparing a liquid in which inorganic particles are dispersed, it is more preferable to use a ball mill, a bead mill, or the like to apply a shearing force, because fine particles can be uniformly dispersed. In dispersing the inorganic particles, a dispersing aid may be added as appropriate. The dispersing aid can be freely selected from known dispersing aids.
The kind of the polymer component is not particularly limited. Examples thereof include at least 1 selected from polysaccharides, cellulose derivatives, animal water-soluble polymers, lignin derivatives, water-soluble synthetic polymers, monosaccharides, disaccharides, oligosaccharides, amino acids, gallic acid, tannins, saccharines, saccharine salts, butynediols, sugar alcohols such as sorbitol, and polyols such as glycerin, 1, 3-butanediol, and dipropylene glycol.
The solvent is not particularly limited as long as it can dissolve and disperse the above-mentioned materials, but is preferably water. Multiple solvents may also be mixed. The temperature at the time of mixing is preferably 50℃to 200 ℃.
The temperature at the time of drying is not particularly limited as long as the polymer component is not decomposed and distilled off, and can be selected from 50 to 200 ℃. Drying under an inert atmosphere and drying under vacuum may be performed.
The polymer-coated composite particles thus obtained may be subjected to a crushing step and a sieving step, as necessary, to remove coarse agglomerated particles.
The content of the polymer component can be confirmed by, for example, heating the sufficiently dried polymer-coated composite particles to a temperature equal to or higher than the decomposition temperature of the polymer component and lower than the oxidation temperature of silicon and carbon (for example, 300 ℃) and measuring the mass of the composite material after the decomposition of the polymer component. Specifically, the content of the polymer component is (a-B) when the mass of the polymer-coated composite particles before heating is Ag and the mass of the heated composite particles is Bg. The content can be calculated by { (A-B)/A }. Times.100.
The above measurement can be performed using Thermogravimetry (TG). The amount of the sample to be used is preferably small because it can be measured with high accuracy.
The composite particles according to the present invention are hardly oxidized in a coating treatment in water, that is, when a surface coating layer is formed by a wet method using water. The surface of the composite particle body can be uniformly coated.
Examples of the effect of the surface coating include (i) suppression of oxidation of silicon within the composite particles over time, (ii) improvement of initial coulombic efficiency, and (iii) improvement of cycle characteristics.
(i) The suppression of oxidation of silicon within the composite particles over time means suppression of oxidation of silicon over time when the composite particles are exposed to air or an oxygen-containing gas atmosphere. The presence of the surface coating layer on the surface of the composite particles can further suppress the invasion of air or an oxygen-containing gas into the composite particles.
(ii) The improvement of initial coulombic efficiency means that the amount of lithium ions trapped by the composite particles is reduced at the time of first lithium ion intercalation into the composite particles inside the lithium ion battery. When an electrolyte solution decomposition product film (SEI < Solid Electrolyte Interface > film) is formed on the surface of the composite particles or at the lithium ion entrance into the composite particles after insertion of lithium ions into the composite particles, the proportion of lithium ions that cannot be detached from closed pores in the composite particles increases, and the initial coulomb efficiency decreases. In the case of inserting lithium ions 2 nd and later, the SEI film is present, so that the rate of lithium ions trapped by the composite particles is significantly reduced. In this way, since the problem is trapping of lithium ions at the time of first lithium ion insertion, if a surface coating layer is present on the surface of the composite particles, insertion of lithium ions into pores that are likely to be blocked by the SEI film can be prevented, and initial coulombic efficiency is improved.
(iii) The improvement of cycle characteristics means that the decrease in capacity when the composite particles are applied to a lithium ion battery and repeatedly charged and discharged is suppressed. In a lithium ion battery, it is considered that when charge and discharge are repeated, silicon in the composite particles reacts with fluorine as a constituent element of an electrolyte solution, and dissolves out as a fluorinated silicon compound. If silicon is eluted, the specific capacity of the composite particles decreases. If a surface coating layer is present on the surface of the composite particles, elution of silicon is suppressed, and a decrease in the capacity of the composite particles is suppressed. In addition, by the surface coating, the resistance is reduced, the coulomb efficiency is improved, and the cycle characteristics are improved.
[4] Negative electrode active material
The negative electrode active material according to an embodiment of the present invention contains the composite particles according to the present invention. The composite particles according to the present invention may be used in combination of two or more kinds. The anode active material may further contain other components. As the other component, a component generally used as a negative electrode active material of a lithium ion secondary battery is exemplified. Examples thereof include graphite, hard carbon, soft carbon, lithium titanate (Li 4 Ti 5 O 12 ) And alloy-based active materials such as silicon and tin, and composite materials thereof. For these components, generally, a particulate component is used. As the component other than the composite particles, one kind may be used, or two or more kinds may be used. Among them, graphite particles and hard carbon are particularly preferably used.
When the negative electrode active material is formed by containing other components, the composite particles are adjusted so that the content of the composite particles in the negative electrode active material is 1 to 50 mass%. Preferably, the content is adjusted to 2 to 25 mass%. By mixing the above-mentioned other components, a negative electrode active material having excellent characteristics of other carbon materials can be formed while maintaining excellent characteristics of the composite particles. When a plurality of materials are used as the negative electrode active material, the materials may be used after being mixed in advance, or may be added sequentially at the time of preparing a slurry for forming a negative electrode mixture, which will be described later.
As a device for mixing the composite particles with other materials, a commercially available mixer or stirrer can be used. Specific examples thereof include mixers such as mortar, ribbon mixer, V-type mixer, W-type mixer, single blade mixer, and noda mixer.
[5] Negative electrode mixture layer
The negative electrode mixture layer according to an embodiment of the present invention contains the negative electrode active material described in [4 ].
The negative electrode mixture layer of the present invention can be used as a negative electrode mixture layer for a lithium ion secondary battery. The negative electrode mixture layer is generally composed of a negative electrode active material, a binder, and a conductive auxiliary agent as an optional component.
The method for producing the negative electrode mixture layer can be, for example, a known method as shown below. A slurry for forming a negative electrode mixture is prepared using a negative electrode active material, a binder, a conductive auxiliary agent as an optional component, and a solvent. The slurry is applied to a current collector such as copper foil and dried. It was further dried under vacuum to remove the solvent. The resulting structure is sometimes referred to as a negative electrode sheet. The negative electrode sheet is composed of a negative electrode mixture layer and a current collector. The negative electrode sheet is cut or punched into a desired shape and size, and then pressed to increase the density of the electrode mixture layer (sometimes referred to as electrode density). If the electrode density is increased, the energy density of the battery is increased. The pressing method is not particularly limited as long as it can be processed into a desired electrode density, but one-axis pressing, roller pressing, and the like are exemplified. In the embodiment described below, the pressing step is exemplified after the shape processing, but the shape processing may be performed after the pressing. In the present invention, this structure having a desired shape and electrode density is referred to as a negative electrode. The negative electrode includes a negative electrode in which a collector tab is attached to a current collector as necessary.
The binder may be selected and used as long as it is a binder generally used in a negative electrode mixture layer of a lithium ion secondary battery. Examples thereof include polyethylene, polypropylene, ethylene propylene diene monomer rubber, butadiene rubber, styrene-butadiene rubber (SBR), butyl rubber, acrylate rubber, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyethylene oxide, polypropylene oxide, polyphosphazene, polyacrylonitrile, carboxymethyl cellulose (CMC) and salts thereof, polyacrylic acid, and polyacrylamide. One kind of binder may be used, or two or more kinds may be used. The amount of the binder is preferably 0.5 to 30 parts by mass relative to 100 parts by mass of the negative electrode material.
The conductive additive is not particularly limited as long as it imparts electron conductivity and dimensional stability (the function of absorbing volume changes associated with lithium intercalation and deintercalation) to the electrode. For example, the number of the cells to be processed, examples thereof include carbon nanotubes, carbon nanofibers, vapor-phase carbon fibers (for example, "VGCF (registered trademark) -H made by zhaokogaku corporation), conductive carbon black (for example," dujin "made by duhon corporation, the registered trademark), and" SUPER C65 "made by the company of b. The company's company SUPER C45, conductive graphite (for example, company's company KS6L, company's company the b-strap and the strap may be used in various ways, such as by" SFG6L "of b-strap and the like.
The conductive auxiliary agent preferably contains carbon nanotubes, carbon nanofibers or vapor phase carbon fibers, and the fiber length of the conductive auxiliary agent is preferably D of the composite particles V50 More than 1/2 of the total weight of the product. If the length is set to this value, these conductive assistants crosslink between the negative electrode active material including the composite particles, and the cycle characteristics can be improved. In addition, a single-wall type or multi-wall type conductive additive having a fiber diameter of 15nm or less is preferable because the amount of crosslinking is increased compared with other conductive additives at the same amount. Further, since the electrode is softer, it is more preferable from the viewpoint of increasing the electrode density.
The amount of the conductive auxiliary agent is preferably 1 to 30 parts by mass relative to 100 parts by mass of the negative electrode material.
The solvent used in preparing the electrode coating slurry is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), isopropanol, tetrahydrofuran (THF), water, and the like. In the case of an adhesive using water as a solvent, a tackifier is also preferably used in combination. The amount of the solvent can be adjusted so that the slurry has a viscosity that is easy to apply to the current collector.
[6] Lithium ion secondary battery
The lithium ion secondary battery according to the present invention includes the negative electrode mixture layer. The lithium ion secondary battery generally includes a negative electrode composed of the negative electrode mixture layer and a current collector, a positive electrode composed of a positive electrode mixture layer and a current collector, at least one of a nonaqueous electrolyte and a nonaqueous polymer electrolyte present therebetween, a separator, and a battery case accommodating them. The lithium ion secondary battery may include the negative electrode mixture layer, and other structures may be used without particular limitation, including conventionally known structures.
The positive electrode mixture layer is generally composed of a positive electrode material, a conductive auxiliary agent, and a binder. The positive electrode in the lithium ion secondary battery can use a general structure in a general lithium ion secondary battery.
The positive electrode active material is not particularly limited as long as it is a material in which electrochemical lithium intercalation/deintercalation can be reversibly performed and the reactions are sufficiently higher than the standard redox potential of the negative electrode reaction. For example, liCoO can be suitably used 2 、LiNiO 2 、LiMn 2 O 4 、LiCo 1/3 Mn 1/3 Ni 1/3 O 2 、LiCo 0.6 Mn 0.2 Ni 0.2 O 2 、LiCo 0.8 Mn 0.1 Ni 0.1 O 2 Carbon coated LiFePO 4 Or mixtures thereof.
As the conductive auxiliary, binder, and solvent for preparing the slurry, the materials listed in the item of the negative electrode are used. As the current collector, aluminum foil is suitably used.
As the nonaqueous electrolyte solution and the nonaqueous polymer electrolyte solution used for the lithium ion battery, materials known as an electrolyte solution of a lithium ion secondary battery can be used. For example, using LiClO 4 、LiPF 6 、LiAsF 6 、LiBF 4 、LiSO 3 CF 3 、CH 3 SO 3 Lithium salts such as Li are dissolved in the following solvents and polymers. Examples of the solvent include nonaqueous solvents such as ethylene carbonate, diethyl carbonate, dimethyl carbonate, methylethyl carbonate, propylene carbonate, butylene carbonate, acetonitrile, propionitrile, dimethoxyethane, tetrahydrofuran, and γ -butyrolactone; gel-like polymers containing polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, and the like; polymers having an ethylene oxide bond, and the like.
In addition, a small amount of an additive generally used in an electrolyte of a lithium ion battery may be added to the nonaqueous electrolyte. Examples of the substance include Vinylene Carbonate (VC), biphenyl, propane Sultone (PS), fluoroethylene carbonate (FEC), and Ethylene Sultone (ES). VC and FEC are preferred. The amount of the additive is preferably 0.01 to 20% by mass based on 100% by mass of the nonaqueous electrolytic solution.
The separator may be selected from separators used in general lithium ion secondary batteries, including combinations thereof, and examples thereof include microporous films made of polyethylene or polypropylene. In addition, siO may be used 2 、Al 2 O 3 And a separator in which the particles are mixed as a filler with such a separator to adhere to the surface.
The battery case is not particularly limited as long as it can accommodate the positive electrode and the negative electrode, and the separator and the electrolyte. In addition to the cases of the battery pack, the 18650 type cylindrical battery, the coin type battery, and the like, which are standardized in the industry, cases in the form of an aluminum pack can be freely designed and used.
Each electrode can be used by packaging after lamination. The battery cells can be connected in series and used as a battery or a module.
Examples
The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
The physical property values were measured and the battery was evaluated as follows.
[1] Determination of physical Property values
[1-1] X-ray photoelectron spectroscopy (XPS: X-ray Photoelectron Spectroscopy)
The sample was placed on the adhesion surface of the double-sided tape attached to the Si substrate using a small spatula, and the double-sided tape of the base was uniformly spread so as not to be exposed, and the measurement surface was gently pressed using the small spatula so as to be flat to some extent. The range of spreading the sample is larger than the measurement range (about 100 μm. Phi.). This is to allow only complex particles to be spread over the measurement range. The sample was measured by the following method.
[ measuring apparatus ]
The device comprises: PHIQuantu II (manufactured by America Co., ltd.)
An X-ray source: al monochrome (25W, 15 kV)
Analysis range: phi 100 μm
Electron, ion neutralization gun: ON (ON)
Photoelectron detection angle: 45 degrees
Narrow scan
And (3) energy communication: 55eV step: 0.2eV residence time: 20ms of
Scanning time: o (25) C, si (50)
[ analytical method ]
[ energy correction ]
The narrow spectrum was corrected so that the peak of 1s of carbon became 284.6 eV.
[ C, O, si atomic number ratio A ] C 、A O 、A Si ]
The area ratio of the narrow spectrum of C, O, si was calculated as the atomic number ratio. C. Atomic number ratio A of all O and Si C 、A O 、A Si The total of (2) is 1.00.
[ Si seed State ratio B ] SiO2 、B SiO 、B Si ]
Regarding the 2p narrow spectrum of Si, peak fitting was performed by the following method to calculate the state ratio B of Si species SiO2 、B SiO 、B Si 。
(chemical shift) Si 0 valence = 99eV, si 2 valence = 101eV, si 4 valence = 103eV
The half-width and peak top were automatically adjusted by analysis software so that the residual error between the peak fitting result and the measurement result was minimized. The peak top was adjusted to a range of ±0.5eV for the width 3 component. The analysis software used was software attached to the measurement device.
Background subtraction method: shirley process
Function: gauss-Lorentz
The valence of Si 0 means so-called elemental Si. Si 2 valence means SiO. Si 4 valence means SiO 2 . Regarding the 1-valent and 3-valent of Si, since the intensity is small, the accuracy of peak fitting becomes low instead, and is therefore excluded. Silicon carbide is generally contained in the valence of Si 2, but when the peak shape of the C1s narrow spectrum is observed, no disturbance (shoulder, tailing, etc.) of the peak shape involved in chemical shift of 282.5 to 283.0eV derived from silicon carbide is observed, and therefore it is considered that the amount of silicon carbide present is not more than the detection lower limit. Thus, the peak of the Si 2 valence is considered to mean SiO only.
[1-2] hydrophobicity
Pure water at the same temperature as room temperature was poured into a 20mL glass sample bottle (trunk diameter. Times. Height: phi. 28 mm. Times.61 mm) to a depth of about 1 cm. Here, 0.05g of the complex particles were weighed on a piece of medicine-wrapping paper, and the complex particles were slowly put into the sample bottle. At this time, the height of the composite particles to be put into the water is within 0.5 to 3.0cm from the water surface. After the pouring, the sample bottle was left to stand in place, and the infiltration behavior of water into the composite particles was observed. Visual confirmation revealed that the composite particles did not reach the bottom of the sample bottle even after standing for 5 minutes, and were considered to be hydrophobic. The powder sinking into water within 5 minutes under the same conditions was regarded as a hydrophilic sample.
[1-3] true Density determination
After the sample was dried at 180℃for 12 hours in vacuo, the sample was filled in a glove box under a dry argon atmosphere to form 4 to 6 measurement cells, and the weight of the sample was measured after compacting the cells 100 times or more. Thereafter, the sample was taken out to the atmosphere, and dry density measurement by a constant volume expansion method using helium gas was performed by the following method, to calculate the true density.
The device comprises: micromeritics AccuPyc (registered trademark) II 1340 gas pycnometer unit: aluminum depth 39.3mm and inner diameter 18mm
Carrier gas: helium gas
Gas pressure: 19.5psiG (134.4 kPaG)
Number of purges at measurement: 200 times
Temperature: 25 ℃ +/-1 DEG C
[1-4]Raman Si peak, I Si /I G Raman R value (I D /I G )
The measurement was performed under the following conditions.
Microscopic raman spectrometry apparatus: labRAM (registered trademark) manufactured by Horikoshi corporation, HR evaluation
Excitation wavelength: 532nm
Exposure time: 10 seconds
Cumulative number of times: 2 times
Diffraction grating: 300 strips/mm (600 nm)
Measuring a sample: the composite particles were placed on the glass specimens using a small spatula to make the powder uniform. The measurement range is set to be larger than the measurement range described below.
Measurement range: 80 μm in the longitudinal direction and 100 μm in the transverse direction. Only complex particles are spread over the measurement range.
Point number: 100 point measurements were performed with a longitudinal feed of 17.8 μm and a transverse feed of 22.2 μm,
the spectrum obtained by averaging these was obtained, and the following analysis was performed.
450-495 cm in Raman spectrum is observed -1 Si peak of (c).
The intensity of the Si peak was set to I si And will be 1580cm -1 Peak intensity in the vicinity (I) G ) The ratio of (1) is set to (I Si /I G )。
1350cm -1 Peak intensity in the vicinity (I) D ) And (I) G ) Is set to R value (I D /I G )。
The height from the base line to the peak top after the correction is set as the peak intensity.
[1-5] powder X-ray diffraction measurement (powder XRD)
The sample was filled into a glass sample plate (window portion longitudinal X. Transversal X: 18mm X20 mm, depth: 0.2 mm), and the measurement was performed by the following method.
XRD device: smartLab (registered trademark) manufactured by k corporation
An X-ray source: cu-K alpha ray
K beta ray removal method: ni filter
X-ray output: 45kV and 200mA
Measurement range: 10.0 to 80.0 DEG
Scanning speed: 10.0 °/min
The obtained XRD pattern was subjected to background removal, kα2 component removal, and smoothing using analysis software (PDXL 2, available from K corporation), and then subjected to peak-type fitting, to obtain the peak position, intensity, and half-width.
The Si (111) plane is a diffraction peak near 2θ=28°, and the SiC (111) plane is a diffraction peak near 2θ=35°.
[1-6] particle size distribution measurement
A sample in a small amount of 1 cup of a spatula and a stock solution of 32 mass% of a nonionic surfactant (SARAYA, proprietary) were diluted 100 times, and 2 drops of the diluted stock solution were added to 15mL of water, and the mixture was ultrasonically dispersed for 3 minutes. The dispersion was measured by the following method.
The device comprises: laser diffraction particle size distribution measuring instrument manufactured by Fahren corporation (LMS-2000 e)
Analysis: the volume-based cumulative particle size distribution was calculated to obtain a 50% particle diameter D V50 (μm), 90% particle diameter D V90 (μm)。
[1-7] silicon content
The silicon content of the sample was measured under the following conditions.
Fluorescent X-ray device: NEX CG manufactured by Proprietary corporation
Tube voltage: 50kV
Tube current: 1.00mA
Sample cup: phi 32 mL 12mL CH1530
Sample weight: 2-3 g
Sample height: 5-18 mm
The sample cup was filled with a sample, and the silicon content in the composite particles was calculated in mass% using the basic parameter (FP method) by the measurement method described above.
[1-8] oxygen content
A 20mg sample was weighed into a nickel bag, and the oxygen content in the composite particles was calculated in mass% by using an oxygen/nitrogen analyzer EMGA (registered trademark) -920 (manufactured by horiba, ltd.). Argon was used as the carrier gas. The oxygen content in the composite particles is divided by the silicon content to obtain the oxygen content in mass% when the silicon content in the composite particles is set to 100 mass%.
The oxygen content was measured within 2 days after the production of the composite particles.
[1-9] scanning electron microscope (Scanning Electron Microscope: SEM), energy dispersive X-ray analysis device (Energy Dispersive X-ray Spectroscopy: EDS)
The sample was carried on a carbon tape, and in the case of particle observation, observation was performed as it is. In the case of cross-section observation, a sample obtained by cross-section processing using a cartridge made by japan electronics corporation was observed. The observation and measurement were performed by the following methods.
SEM: scanning electron microscope device: regulus (registered trademark) 8220 (Hi-Tek made by Hi-Tek, kagaku Co., ltd.)
EDS: XFlash (registered trademark) 5060 flutquad (manufactured by brutal corporation)
Acceleration voltage: 1-20 kV
Observation magnification: 500-5000 times (appropriately selected according to the particle size)
[1-10] BET specific surface area, pore volume (Nitrogen adsorption test)
Use of a stick as a measurement deviceNOVA (registered trademark) 4200e manufactured by taro low-speed co-polymer corporation, is introduced into a sample cell (9 mm. Times.135 mm) so that the total surface area of the sample is 2 to 60m 2 The sample was placed therein, dried at 300℃under vacuum for 1 hour, and then the weight of the sample was measured. Nitrogen was used as the gas for measurement.
The lowest relative pressure was set to 0.005 and the highest relative pressure was set to 0.995 at the time of measurement. The BET specific surface area of the porous carbon material is calculated by a BET multipoint method from adsorption isotherm data of less than 0.08 in the vicinity of 0.005 from the relative pressure. The BET specific surface area of the composite particles was calculated by the BET multipoint method from adsorption isotherm data of 3 points in the vicinity of 0.1, 0.2 and 0.3 relative pressures. For total pore volume V 0.99 The adsorption amount at the relative pressure of 0.99 was calculated by straight line approximation from adsorption isotherm data of 2 points before and after the relative pressure of 0.99. For pore volume V at a relative pressure of 0.01 0.01 The adsorption amount at the relative pressure of 0.01 was calculated by straight line approximation from adsorption isotherm data of 2 points before and after the relative pressure of 0.01.
At this time, the density of the nitrogen liquid was set to 0.808 (g/cm 3 ) The volume of 1 mole of nitrogen in the standard state was set to 22.4133L, and the atomic weight of nitrogen was set to 14.0067.
[1-11] determination of Polymer component content
The measurement was performed by the following method.
TG-DTA device: TG-DTA2000SE manufactured by NETZSCH JAPAN
Sample weight: 10-20 mg
Sample tray: alumina system
Reference disc: alumina system
Gas atmosphere: ar (Ar)
Gas flow rate: 100 mL/min
And (5) temperature rise measurement: 10 ℃/min
Measuring temperature range: room temperature to 1000 DEG C
The polymer component content was calculated using the amount of the polymer component as the amount of the polymer component reduced by thermal decomposition at 200 to 350 ℃.
[2] Oxidation resistance measurement of composite particles based on aqueous sample dispersion
A20 mL glass sample bottle was charged with 2g of a stirrer and pure water. A sample of 0.05g was put thereinto and covered with a septum made of silicone rubber. The hydrogen concentration in the gas phase in the sample bottle was measured while stirring at room temperature (20 to 26 ℃) using a magnetic stirrer.
Hydrogen is produced by oxidation of silicon in the composite particles by water. Therefore, a high hydrogen concentration in the gas phase means that the composite particles are easily oxidized, and a low hydrogen concentration means that the composite particles are difficult to oxidize.
The hydrogen concentration was measured using a real-time mass spectrometer. For the hydrogen concentration, sensitivity correction was performed using the nitrogen concentration. The same measurement was performed without adding a sample, and the hydrogen concentration calculated at this time was corrected to 0% by volume.
The gas in the sample bottle is sampled by a real-time mass spectrometer using a capillary tube penetrating a separator. In order to make the air pressure inside the sample bottle constant, an injection needle is inserted into the partition plate in addition to the capillary tube of the real-time mass spectrometer so that air in the room can be introduced.
The hydrogen generation concentration was compared using the average hydrogen concentration 50 to 60 minutes after the start of measurement. Since most of the air in the sample bottle was measured immediately after the start of the measurement, a value that was free of time from the start of the measurement was used. Further, the sampling flow rate of the real-time mass spectrometer was 1sccm. In addition, the sample bottle was set so that the capillary tube was not in contact with the liquid surface, so that the real-time mass spectrometer did not aspirate the aqueous dispersion of the sample.
Real-time mass analyzer: one member of the group of member is made by the company of PFEIFER VACUUM, OMNISTAR (registered trademark) GSD350
[3] Battery evaluation
[3-1] production of negative electrode sheet
Styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) are used as binders.
Specifically, an SBR aqueous dispersion in which SBR was dispersed in an amount of 40% by mass of the solid content and a CMC aqueous solution in which CMC powder was dissolved were obtained.
As the mixed conductive auxiliary agent, prepared were carbon black (upper C45 (registered trademark), bileve, manufactured by porter company) and single-walled carbon nanotubes (TUBALL (registered trademark) WPB-030, manufactured by ocsial company) at a ratio of 5:1, and a conductive additive obtained by mixing the above materials in a mass ratio.
The composite particles and graphite particles were mixed so that the silicon concentration was 5.9 mass% in the total amount of the negative electrode active material, to obtain a negative electrode active material. 96.4 parts by mass of a negative electrode active material, 0.6 parts by mass of a mixed conductive additive, 1.5 parts by mass of an aqueous CMC solution of CMC solid content, and 1.5 parts by mass of an aqueous SBR dispersion of SBR solid content were mixed, and water for viscosity adjustment was added thereto in an appropriate amount, followed by kneading by a rotation/revolution mixer (manufactured by the company corporation) to obtain a slurry for forming a negative electrode mixture layer. The slurry concentration is 45-55 mass%.
As graphite particles, bet=2.7m was used 2 /g、D V10 ＝7μm、D V50 ＝14μm、D V90 27 μm, tap density=0.98 g/cm 3 Artificial graphite with initial discharge specific capacity of 360mAh/g and initial coulombic efficiency of 92%.
The negative electrode mixture layer forming slurry was uniformly applied onto a copper foil having a thickness of 20 μm as a current collecting foil using a doctor blade having a gap of 150 μm, dried by a hot plate, and then vacuum-dried at 70 ℃ for 12 hours, thereby forming a negative electrode mixture layer on the current collecting foil. This is called a negative electrode sheet (sheet composed of a negative electrode mixture layer and a collector foil).
Punching the negative electrode sheet to 16mm phi, press-forming the negative electrode sheet by a one-shaft press, and adjusting the density of the negative electrode mixture layer to 1.6g/cm 3 Thus, a negative electrode was obtained.
The electrode density (anode density) of the anode was calculated as follows. The mass and thickness of the negative electrode obtained by the above method were measured, and the mass and thickness of the negative electrode mixture layer was obtained by subtracting the mass and thickness of the separately measured collector foil punched out to 16mm phi from this, and the electrode density (negative electrode density) was calculated from the values.
[3-2] production of coin cell (lithium counter electrode cell)
In an insulating gasket (inner diameter: about 18 mm) made of polypropylene, the negative electrode and a separator (microporous membrane made of polypropylene) obtained by impregnating an electrolyte with a metal lithium foil (thickness: 1.7 mm) punched out of 17.5mm phi were laminated. At this time, the surface of the negative electrode mixture layer of the negative electrode is laminated so as to face the metal lithium foil with the separator interposed therebetween. This was set in 2320 coin-type battery, and sealed with a caulking machine to form a test battery (lithium counter battery).
The electrolyte in the lithium counter battery is prepared by using ethylene carbonate, methyl ethyl carbonate and diethyl carbonate according to the volume ratio of 3:5:2, and 1 part by mass of Vinylene Carbonate (VC) was mixed with 100 parts by mass of the solvent obtained by mixing at a ratio of 2, and further, lithium hexafluorophosphate (LiPF) 6 ) A liquid obtained by dissolving the above-mentioned polymer in a concentration of 1 mol/L.
[3-3] initial specific charge capacity, initial specific discharge capacity
Tests were performed using lithium counter cells. Constant current (constant current: CC) charging was performed from OCV (Open Circuit Voltage: open circuit voltage) to 0.005V at a current value corresponding to 0.1C. The charging was switched to constant voltage (constant voltage: CV) at the point of time when 0.005V was reached. The off condition is set at a point in time when the current value decays to 0.005C. The specific capacity at this time is set to the initial charge specific capacity. Then, a constant current discharge was performed at a current value corresponding to 0.1C, with the upper limit voltage of 1.5V. The specific capacity at this time was set as the initial discharge specific capacity.
The test was carried out in a constant temperature bath set at 25 ℃. In this case, the "specific capacity" is a value obtained by dividing the capacity by the mass of the anode active material. In this test, the "current value corresponding to 1C" refers to a current level at which the capacity of the negative electrode estimated from the theoretical specific capacities (4200 mAh/g and 372mAh/g, respectively) and the mass of Si and carbon (including graphite) of the negative electrode active material contained in the negative electrode can be discharged for 1 hour.
[3-4] initial coulombic efficiency
The initial coulombic efficiency (%) is set as a value expressed as a percentage, which is a value obtained by dividing the initial specific discharge capacity by the initial specific charge capacity, (initial specific discharge capacity)/(initial specific charge capacity) ×100.
[3-5] silicon utilization
The specific capacity of silicon in the composite particles was calculated from the initial specific discharge capacity and the composition of the negative electrode active material, and a value obtained by dividing the value by the theoretical specific capacity of silicon (4200 mAh/g) was expressed as a percentage, and was set as a silicon utilization (%). The closer this value is to 100%, the more effectively the silicon capacity in the composite particles can be used.
The calculation of the specific capacity of silicon in the composite particles was performed using the following formula based on the silicon concentration (i.e., the proportion of silicon (mass%) and the carbon concentration (i.e., the proportion of carbon (mass%))) (the proportion of graphite and carbon in the composite particles (mass%)), the theoretical specific capacity of carbon (372 mAh/g), and the initial specific discharge capacity in the negative electrode active material.
Specific capacity of silicon in composite particles= (initial specific discharge capacity- (carbon concentration/100) ×theoretical specific capacity of carbon)/(silicon concentration/100)
The carbon concentration and the silicon concentration of the above formula were calculated from the negative electrode active material composition and the composition of the composite particles. The carbon content in the carbon material in the composite particles was set to 100 mass%.
Examples 1, 2, 4, 5, 7 to 11
The porous carbon having the physical properties shown in table 1 was charged into a tubular furnace, the inside of the tubular furnace was replaced with argon, and then a silicon-containing gas was introduced into the tubular furnace under the conditions of step (a) shown in table 1, and the reaction was performed.
Next, the inside of the tubular furnace was replaced with argon, and then depressurized, and the gases (hydrocarbon gas and diluent gas) used in the step (B) described in table 1 were introduced into 300sccm to be at atmospheric pressure (760 torr). Thereafter, the reaction was carried out under the conditions of step (B) shown in table 1.
Next, after the inside of the tubular furnace was replaced with argon, a gas was introduced (steps C-1 and C-3) or filled (step C-4) into the tubular furnace under the conditions of step (C) described in table 1, and the reaction was performed, thereby obtaining composite particles. The step (C) is performed in the order of the steps C-1, C-2, C-3 and C-4. The non-performed steps are shown in table 1. The structure and physical properties of the obtained composite particles are shown in table 2. The evaluation results are shown in table 3.
Example 3
The porous carbon having the physical properties shown in table 1 was charged into a tubular furnace, the inside of the tubular furnace was replaced with argon, and then a silicon-containing gas was introduced into the tubular furnace under the conditions of step (a) shown in table 1, and the reaction was performed.
Next, after the inside of the tubular furnace was replaced with argon, a gas (hydrocarbon gas and diluent gas) was introduced into the tubular furnace under the conditions of step (B) shown in table 1, and the reaction was performed.
Next, after the inside of the tubular furnace was replaced with argon, a gas was introduced (steps C-1 and C-3) or filled (step C-4) into the tubular furnace under the conditions of step (C) described in table 1, and the reaction was performed, thereby obtaining composite particles. The step (C) is performed in the order of the steps C-1, C-2, C-3 and C-4. The non-performed steps are shown in table 1. The structure and physical properties of the obtained composite particles are shown in table 2. The evaluation results are shown in table 3.
Example 6
[ production of inorganic particle Dispersion ]
As the inorganic particles, an average particle diameter D was prepared V50 3 μm of flake graphite (KS-6, manufactured by Timcal) and acetylene black (HS 100, manufactured by Dimens Co., ltd.). 156g of flake graphite, 40g of acetylene black and 4g of carboxymethyl cellulose were put into 800g of water, and dispersed and mixed by a bead mill to obtain an inorganic particle dispersion (solid content 20 mass%).
[ production of Polymer-coated composite particles ]
7g of the composite particles obtained in example 1, 1.98g of water, 3.84g of a 2.5 mass% tamarind gum solution, 0.43g of a 2.5 mass% sorbitol aqueous solution, and 1.60g of an inorganic particle dispersion were prepared.
The water and the tamarind gum aqueous solution were put into a polyethylene capped bottle having a content of 105mL, and mixed at 1000rpm for 2 minutes by a rotation/revolution mixer (manufactured by the company, inc.). The composite particles were added and mixed at 1000rpm for 2 minutes. The inorganic particle dispersion was added and mixed at 1000rpm for 2 minutes. The aqueous sorbitol solution was added and mixed at 1000rpm for 2 minutes. The obtained slurry was spread on a SUS-made tray, and dried at 150℃for 5 hours by a hot air dryer. The dried solid content was recovered, and agglomerated particles were crushed by an agate mortar. SEM observation of the obtained composite particles revealed that the surfaces of the core particles had a structure in which the flaky graphite and the acetylene black were protruded. The content of the polymer component was 1.5% by mass.
The evaluation results of the polymer-coated composite particles are shown in table 3. It was found that the hydrogen concentration in the gas phase in the aqueous sample dispersion vessel was lower than in example 1 in the polymer-coated composite particles, and the oxidation resistance was improved as compared with the composite particles of example 1. The polymer coating slightly increases the oxygen content of the composite particles, and thus the initial coulombic efficiency is slightly lowered, but there is an effect of improving the oxidation resistance.
Comparative example 1, 4
The porous carbon having the physical properties shown in table 1 was charged into a tubular furnace, the inside of the tubular furnace was replaced with argon, and then a silicon-containing gas was introduced into the tubular furnace under the conditions of step (a) shown in table 1, and the reaction was performed.
Next, after the inside of the tubular furnace was replaced with argon, the reaction was carried out by introducing (steps C-1 and C-3) or filling (step C-4) a gas under the conditions of step (C) shown in table 1 without carrying out step (B), and composite particles were obtained. The step (C) is performed in the order of the steps C-1, C-2, C-3 and C-4. With respect to the non-performed process, "-" is filled in. The structure and physical properties of the composite particles are shown in table 2. The evaluation results are shown in table 3.
Comparative example 2
The porous carbon having the physical properties shown in table 1 was charged into a tubular furnace, the inside of the tubular furnace was replaced with argon, and then a silicon-containing gas was introduced into the tubular furnace under the conditions of step (a) shown in table 1, and the reaction was performed.
Next, the inside of the tubular furnace was replaced with argon, and then depressurized, and the gases (hydrocarbon gas and diluent gas) used in the step (B) described in table 1 were introduced into 300sccm to be at atmospheric pressure (760 torr). Thereafter, the reaction was carried out under the conditions of step (B) shown in table 1.
Next, after the inside of the tubular furnace was replaced with argon, a gas was introduced (steps C-1 and C-3) or filled (step C-4) into the tubular furnace under the conditions of step (C) described in table 1, and the reaction was performed, thereby obtaining composite particles. The step (C) is performed in the order of the steps C-1, C-2, C-3 and C-4. With respect to the non-performed process, "-" is filled in. The structure and physical properties of the composite particles are shown in table 2. The evaluation results are shown in table 3.
Comparative example 3
The porous carbon having the physical properties shown in table 1 was charged into a tubular furnace, the inside of the tubular furnace was replaced with argon, and then a silicon-containing gas was introduced into the tubular furnace under the conditions of step (a) shown in table 1, and the reaction was performed.
Next, after the inside of the tubular furnace was replaced with argon, a gas (hydrocarbon gas and diluent gas) was introduced into the tubular furnace under the conditions of step (B) shown in table 1, and the reaction was performed.
Then, the resultant was cooled to room temperature to obtain composite particles. The structure and physical properties of the composite particles are shown in table 2. The surface carbon coating was confirmed by cross-sectional SEM observation, and the average thickness thereof was 21nm. The evaluation results are shown in table 3.
[ Table 1-1]
[ tables 1-2]
[ tables 1 to 3]
[ Table 2-1]
[ Table 2-2]
[ tables 2 to 3]
TABLE 3
Here, the average hydrogen concentration when each sample was immersed in water was measured, and the battery characteristics of the composite particles and the polymer-coated composite particles, which were not immersed in water, were evaluated.
Further, as described at the beginning of the "problem to be solved by the present invention", since the irreversible capacity increases and the initial coulombic efficiency decreases in the oxidized Si/C particles, it is obvious that an experiment for redisplaying the same was not performed.
In the composite particles of examples 1 to 5 and 7 to 11 and the polymer-coated composite particles of example 6, the hydrogen concentration in the gas phase in the aqueous sample dispersion vessel was lower and the oxidation resistance was higher than the products of comparative examples 1, 2 and 4.
Example 5 includes a heat treatment step (step C-2) in step (C). Thus, the hydrogen concentration in the gas phase in the sample aqueous dispersion vessel was lower than in example 4, which did not include step C-2. A is that C /(A C +A Si ×(B SiO2 +B SiO ) In example 5, is smaller than in example 4, so that the oxygen content in the coating layer in example 5 is considered to be large. In comparative examples 1, 2 and 4, the hydrogen concentration was high and the oxidation resistance was low. This is because the coating is not present or insufficient.
The composite particles and polymer-coated composite particles in the examples are considered to have oxidation resistance even when stored in air because they can inhibit oxidation during water dispersion.
In addition, regarding battery characteristics, the composite particles of examples 1 to 5 and 7 to 11 and the polymer-coated composite particles of example 6 have a higher silicon utilization ratio than the products of comparative examples 2 and 3, and silicon in the composite particles can be effectively used. In comparative examples 2 and 3, since silicon carbide is produced due to a high reaction temperature in the step (B), it is considered that silicon utilization rate is low due to a decrease in silicon that can be charged and discharged.
Industrial applicability
The composite particles of the present invention can be suitably used, for example, as a negative electrode active material constituting a negative electrode mixture layer of a lithium ion secondary battery or the like. The lithium ion secondary battery of the present invention can be suitably used for applications requiring high capacity and high output, such as IT devices such as smart phones and tablet PCs, dust collectors, electric tools, electric bicycles, unmanned aerial vehicles, automobiles, and the like.
Claims (16)
1. A composite particle, comprising: particles comprising a carbon material and silicon, and a coating comprising carbon and oxygen on the surface of the particles,
the true density obtained by measuring the dry density using helium was 1.80g/cm 3 Above and 1.99g/cm 3 In the following the procedure is described,
in the raman spectrum of the complex particles,
the peak exists between 450 and 495cm -1 ，
If the intensity of the peak is set as I Si And the strength of the G band is 1580cm -1 The intensity of the nearby peak is set as I G Then I Si /I G Is not more than 1.3 of the total weight of the composition,
if the atomic number ratios of Si, O and C based on the narrow spectrum of the X-ray photoelectron spectroscopy of the composite particles are respectively set as A Si 、A O And A C And analyzing the Si species ratio obtained by Si2p energy spectrum state analysis 2 And SiO are respectively set as B SiO2 、B SiO ，
Then A Si Is not less than 0.05 percent,
the complex particles satisfy at least one of the following formulas (1) and (2):
Y≥0.75 (1)
Y≥－0.32X+0.81 (2)
in formulae (1) and (2), x=i Si /I G ，Y＝A C /(A C +A Si ×(B SiO2 +B SiO ))。
2. The composite particles according to claim 1,
the I is Si /I G Is 0.64 or less, and satisfies the formula (1).
3. The composite particles according to claim 1,
the carbon material is porous carbon, and silicon is contained in at least some of the pores of the porous carbon.
4. The composite particles according to claim 1,
the coating is thin to an extent that it is virtually undetectable when viewed in cross section based on an electron microscope.
5. The composite particles according to claim 1,
in an XRD pattern obtained by powder XRD using Cu-K alpha rays, the half width of a peak on the Si (111) plane is 3.0 DEG or more, the ratio of the peak intensity on the SiC (111) plane to the peak intensity on the Si (111) plane is 0.01 or less, and the R value of the Raman spectrum is 0.26 or more and less than 1.34.
6. The composite particles according to claim 1,
is hydrophobic.
7. The composite particles according to claim 1,
substantially no graphite is contained therein.
8. The composite particles according to claim 1,
50% particle size D in volume-based cumulative particle size distribution V50 1.0 to 30.0 mu m.
9. The composite particles according to claim 1,
the silicon content is 30 to 80 mass% and the oxygen content is 4.0 mass% inclusive.
10. A method for producing composite particles, comprising:
a step (A) of bringing a silicon-containing gas into contact with porous carbon to deposit silicon into pores and surfaces of the porous carbon, thereby obtaining Si/C particles;
a step (B) of bringing a gas containing a hydrocarbon having an unsaturated bond into contact with the Si/C particles at 400 ℃ or lower; and
and (C) oxidizing the hydrocarbon-containing layer obtained in the step (B).
11. The method for producing composite particles according to claim 10,
the step (a) and the step (B) are performed continuously.
12. The method for producing composite particles according to claim 10,
manufacturing the composite particles of claim 1.
13. A polymer-coated composite particle comprising a polymer-coated composite particle,
The composite particle according to claim 1, wherein the inorganic particle-containing polymer component coating layer comprises 1 or more kinds of inorganic particles selected from the group consisting of graphite and carbon black, and a polymer component, and the content of the polymer component is 0.1 to 10.0 mass%.
14. A negative electrode active material, which comprises a negative electrode active material,
comprising the composite particle of claim 1 or the polymer coated composite particle of claim 13.
15. A negative electrode mixture layer, which is prepared from a negative electrode material,
a negative electrode active material according to claim 14.
16. A lithium ion secondary battery, which comprises a battery cell,
a negative electrode mixture layer according to claim 15.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021-163086 | 2021-10-01 | ||
| JP2021163086 | 2021-10-01 | ||
| PCT/JP2022/017905 WO2023053548A1 (en) | 2021-10-01 | 2022-04-15 | Composite particle, production method therefor, and use thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117529450A true CN117529450A (en) | 2024-02-06 |
Family
ID=85503234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280042784.7A Pending CN117529450A (en) | 2021-10-01 | 2022-04-15 | Composite particles, method for producing same, and use thereof |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20240266535A1 (en) |
| EP (1) | EP4411874A1 (en) |
| JP (2) | JP7236613B1 (en) |
| KR (1) | KR20240088634A (en) |
| CN (1) | CN117529450A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117727916A (en) * | 2024-02-07 | 2024-03-19 | 长沙矿冶研究院有限责任公司 | Silicon-oxygen-carbon composite material containing silicon carbide coating and preparation method and application thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116014113B (en) * | 2023-03-23 | 2023-09-19 | 宁德新能源科技有限公司 | Negative electrode material, secondary battery, and electronic device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120264020A1 (en) * | 2010-10-07 | 2012-10-18 | Applied Sciences, Inc. | Method of depositing silicon on carbon nanomaterials |
| KR20240023451A (en) * | 2015-08-28 | 2024-02-21 | 그룹14 테크놀로지스, 인코포레이티드 | Novel materials with extremely durable intercalation of lithium and manufacturing methods thereof |
| CN109004203B (en) * | 2018-08-02 | 2020-12-01 | 内蒙古三信实业有限公司 | Silicon-carbon composite negative electrode material and preparation method thereof |
| JP7456291B2 (en) * | 2020-05-29 | 2024-03-27 | 株式会社レゾナック | Carbon-coated composite materials and their applications |
-
2022
- 2022-04-15 EP EP22875431.3A patent/EP4411874A1/en active Pending
- 2022-04-15 US US18/565,795 patent/US20240266535A1/en active Pending
- 2022-04-15 KR KR1020237042627A patent/KR20240088634A/en unknown
- 2022-04-15 JP JP2022554734A patent/JP7236613B1/en active Active
- 2022-04-15 CN CN202280042784.7A patent/CN117529450A/en active Pending
-
2023
- 2023-01-30 JP JP2023011990A patent/JP2023055814A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117727916A (en) * | 2024-02-07 | 2024-03-19 | 长沙矿冶研究院有限责任公司 | Silicon-oxygen-carbon composite material containing silicon carbide coating and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| EP4411874A1 (en) | 2024-08-07 |
| JPWO2023053548A1 (en) | 2023-04-06 |
| JP7236613B1 (en) | 2023-03-10 |
| US20240266535A1 (en) | 2024-08-08 |
| KR20240088634A (en) | 2024-06-20 |
| JP2023055814A (en) | 2023-04-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3133678B1 (en) | Negative electrode material for lithium-ion battery, and use therefor | |
| EP2924784B1 (en) | Method for producing negative electrode material for lithium ion batteries | |
| CN115667136B (en) | Composite carbon particles and uses thereof | |
| EP4160726A1 (en) | Composite particle, negative electrode active material, and lithium secondary battery | |
| KR20220009962A (en) | Electroactive materials for metal-ion batteries | |
| EP4159675A1 (en) | Composite particles, method for producing same and use of same | |
| CN117529450A (en) | Composite particles, method for producing same, and use thereof | |
| WO2022270539A1 (en) | Composite carbon particles and use thereof | |
| KR20220157988A (en) | Lithium secondary battery composite active material, lithium secondary battery electrode composition, lithium secondary battery electrode and manufacturing method of lithium secondary battery composite active material | |
| EP3767715B1 (en) | Sulfur-carbon composite, preparation method thereof, positive electrode for lithium secondary battery and lithium secondary battery comprising same | |
| JP2023059283A (en) | Composite particles, manufacturing method thereof, and use thereof | |
| EP4411893A1 (en) | Composite particles, negative electrode active material and lithium ion secondary battery | |
| CN117321797A (en) | Composite particle, negative electrode mixture layer, and lithium ion secondary battery | |
| CN115668539A (en) | Composite particle, negative electrode material, and lithium ion secondary battery | |
| WO2024142644A1 (en) | Composite particles, method for producing same and use of same | |
| WO2023053548A1 (en) | Composite particle, production method therefor, and use thereof | |
| WO2024161756A1 (en) | Si-c composite particles, method for producing same, and use of same | |
| WO2024142699A1 (en) | Composite particles, method for producing same and use of same | |
| TW202428510A (en) | Composite particles, method for producing the same and use thereof | |
| WO2024048051A1 (en) | Negative electrode active material and secondary battery | |
| JP2024035246A (en) | Negative electrode active material and secondary battery | |
| CN116235306A (en) | Negative electrode and lithium secondary battery including the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |