CA2128745C - Lithium secondary battery employing a non-aqueous media - Google Patents
Lithium secondary battery employing a non-aqueous mediaInfo
- Publication number
- CA2128745C CA2128745C CA002128745A CA2128745A CA2128745C CA 2128745 C CA2128745 C CA 2128745C CA 002128745 A CA002128745 A CA 002128745A CA 2128745 A CA2128745 A CA 2128745A CA 2128745 C CA2128745 C CA 2128745C
- Authority
- CA
- Canada
- Prior art keywords
- lithium
- secondary battery
- anode
- compound
- lithium secondary
- 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.)
- Expired - Fee Related
Links
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 56
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 54
- 239000012457 nonaqueous media Substances 0.000 title abstract description 6
- 239000010405 anode material Substances 0.000 claims abstract description 40
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 19
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 18
- 238000001354 calcination Methods 0.000 claims abstract description 17
- 239000002243 precursor Substances 0.000 claims abstract description 16
- 150000002894 organic compounds Chemical class 0.000 claims abstract description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 29
- 239000003575 carbonaceous material Substances 0.000 claims description 28
- -1 polycyclic organic compound Chemical class 0.000 claims description 27
- 150000001875 compounds Chemical class 0.000 claims description 25
- 150000002828 nitro derivatives Chemical class 0.000 claims description 15
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 230000000802 nitrating effect Effects 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 8
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 8
- XNKFCDGEFCOQOM-UHFFFAOYSA-N 1,2-dinitronaphthalene Chemical group C1=CC=CC2=C([N+]([O-])=O)C([N+](=O)[O-])=CC=C21 XNKFCDGEFCOQOM-UHFFFAOYSA-N 0.000 claims description 7
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 claims description 7
- 239000011261 inert gas Substances 0.000 claims description 7
- 125000004433 nitrogen atom Chemical group N* 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 239000001301 oxygen Substances 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 239000007795 chemical reaction product Substances 0.000 claims description 4
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 claims description 4
- 229910002651 NO3 Inorganic materials 0.000 claims description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 3
- 229920000620 organic polymer Polymers 0.000 claims description 3
- 125000003367 polycyclic group Chemical group 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 2
- 229910052739 hydrogen Inorganic materials 0.000 claims description 2
- 239000011255 nonaqueous electrolyte Substances 0.000 claims description 2
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 claims 2
- 125000003118 aryl group Chemical group 0.000 claims 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 239000000203 mixture Substances 0.000 description 19
- 238000004458 analytical method Methods 0.000 description 14
- 238000012360 testing method Methods 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 11
- 238000005259 measurement Methods 0.000 description 9
- 239000011295 pitch Substances 0.000 description 9
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 239000011269 tar Substances 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- 238000000921 elemental analysis Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 238000006396 nitration reaction Methods 0.000 description 4
- 239000000376 reactant Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 3
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- 229910032387 LiCoO2 Inorganic materials 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 3
- 229940032159 propylene carbonate Drugs 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 102100022704 Amyloid-beta precursor protein Human genes 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- 101000823051 Homo sapiens Amyloid-beta precursor protein Proteins 0.000 description 2
- 229910013462 LiC104 Inorganic materials 0.000 description 2
- MZRVEZGGRBJDDB-UHFFFAOYSA-N N-Butyllithium Chemical compound [Li]CCCC MZRVEZGGRBJDDB-UHFFFAOYSA-N 0.000 description 2
- FZERHIULMFGESH-UHFFFAOYSA-N N-phenylacetamide Chemical compound CC(=O)NC1=CC=CC=C1 FZERHIULMFGESH-UHFFFAOYSA-N 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- DZHSAHHDTRWUTF-SIQRNXPUSA-N amyloid-beta polypeptide 42 Chemical compound C([C@@H](C(=O)N[C@@H](C)C(=O)N[C@@H](CCC(O)=O)C(=O)N[C@@H](CC(O)=O)C(=O)N[C@H](C(=O)NCC(=O)N[C@@H](CO)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H](CCCCN)C(=O)NCC(=O)N[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCSC)C(=O)N[C@@H](C(C)C)C(=O)NCC(=O)NCC(=O)N[C@@H](C(C)C)C(=O)N[C@@H](C(C)C)C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](C)C(O)=O)[C@@H](C)CC)C(C)C)NC(=O)[C@H](CC=1C=CC=CC=1)NC(=O)[C@@H](NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](CC=1N=CNC=1)NC(=O)[C@H](CC=1N=CNC=1)NC(=O)[C@@H](NC(=O)[C@H](CCC(O)=O)NC(=O)[C@H](CC=1C=CC(O)=CC=1)NC(=O)CNC(=O)[C@H](CO)NC(=O)[C@H](CC(O)=O)NC(=O)[C@H](CC=1N=CNC=1)NC(=O)[C@H](CCCNC(N)=N)NC(=O)[C@H](CC=1C=CC=CC=1)NC(=O)[C@H](CCC(O)=O)NC(=O)[C@H](C)NC(=O)[C@@H](N)CC(O)=O)C(C)C)C(C)C)C1=CC=CC=C1 DZHSAHHDTRWUTF-SIQRNXPUSA-N 0.000 description 2
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 description 2
- 239000012159 carrier gas Substances 0.000 description 2
- 239000011294 coal tar pitch Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- VPUGDVKSAQVFFS-UHFFFAOYSA-N coronene Chemical compound C1=C(C2=C34)C=CC3=CC=C(C=C3)C4=C4C3=CC=C(C=C3)C4=C2C3=C1 VPUGDVKSAQVFFS-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- 229910001486 lithium perchlorate Inorganic materials 0.000 description 2
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 2
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 150000002900 organolithium compounds Chemical class 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229940058401 polytetrafluoroethylene Drugs 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- BBEAQIROQSPTKN-UHFFFAOYSA-N pyrene Chemical compound C1=CC=C2C=CC3=CC=CC4=CC=C1C2=C43 BBEAQIROQSPTKN-UHFFFAOYSA-N 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 238000004566 IR spectroscopy Methods 0.000 description 1
- 229910014549 LiMn204 Inorganic materials 0.000 description 1
- 229910014689 LiMnO Inorganic materials 0.000 description 1
- 229910003005 LiNiO2 Inorganic materials 0.000 description 1
- 229910001290 LiPF6 Inorganic materials 0.000 description 1
- 229910018011 MK-II Inorganic materials 0.000 description 1
- 229910019071 Mg—Ka Inorganic materials 0.000 description 1
- 229910016003 MoS3 Inorganic materials 0.000 description 1
- 229910020050 NbSe3 Inorganic materials 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910003092 TiS2 Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- OLBVUFHMDRJKTK-UHFFFAOYSA-N [N].[O] Chemical compound [N].[O] OLBVUFHMDRJKTK-UHFFFAOYSA-N 0.000 description 1
- 229960001413 acetanilide Drugs 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- RFRXIWQYSOIBDI-UHFFFAOYSA-N benzarone Chemical compound CCC=1OC2=CC=CC=C2C=1C(=O)C1=CC=C(O)C=C1 RFRXIWQYSOIBDI-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- CFHJRIFIUOUTAR-UHFFFAOYSA-N bromoform;tetrachloromethane Chemical compound BrC(Br)Br.ClC(Cl)(Cl)Cl CFHJRIFIUOUTAR-UHFFFAOYSA-N 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- GVEPBJHOBDJJJI-UHFFFAOYSA-N fluoranthrene Natural products C1=CC(C2=CC=CC=C22)=C3C2=CC=CC3=C1 GVEPBJHOBDJJJI-UHFFFAOYSA-N 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- XPFVYQJUAUNWIW-UHFFFAOYSA-N furfuryl alcohol Chemical compound OCC1=CC=CO1 XPFVYQJUAUNWIW-UHFFFAOYSA-N 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000011244 liquid electrolyte Substances 0.000 description 1
- 229910001547 lithium hexafluoroantimonate(V) Inorganic materials 0.000 description 1
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- TVWWSIKTCILRBF-UHFFFAOYSA-N molybdenum trisulfide Chemical compound S=[Mo](=S)=S TVWWSIKTCILRBF-UHFFFAOYSA-N 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 150000002829 nitrogen Chemical class 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 description 1
- 229920003986 novolac Polymers 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229920001197 polyacetylene Polymers 0.000 description 1
- 229920000767 polyaniline Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000128 polypyrrole Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- FVSKHRXBFJPNKK-UHFFFAOYSA-N propionitrile Chemical compound CCC#N FVSKHRXBFJPNKK-UHFFFAOYSA-N 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000036647 reaction Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 150000003346 selenoethers Chemical class 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 239000011318 synthetic pitch Substances 0.000 description 1
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- 239000000057 synthetic resin Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—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
-
- 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
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49108—Electric battery cell making
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
A lithium secondary battery employing a non-aqueous media in which the carbonaceous anode material is prepared by the calcination of an organic compound obtained by reacting a precursor organic compound with a lithium salt.
Description
21287~S
_ IMPROVED LITHIUM SECONDARY BATTERY EMPLOYING A NON-AQUEOUS MEDIA
BACKGROUND OF THE INVENTION
- 1. Field of the Invention The present invention relates to an improved lithium secondary batterY employing a non-aqueous media and exhibiting superior caPaCitY and charge-discharge characteristics.
_ IMPROVED LITHIUM SECONDARY BATTERY EMPLOYING A NON-AQUEOUS MEDIA
BACKGROUND OF THE INVENTION
- 1. Field of the Invention The present invention relates to an improved lithium secondary batterY employing a non-aqueous media and exhibiting superior caPaCitY and charge-discharge characteristics.
2. Description of the Prior Art Lithium secondary ba~tteries using carbonaceous materials as anode materials have already been used to obtain such advantages as high energy density, lightness and compactness and storability over long periods.
However, in resPonse to the trend toward minia-turization of electronic devices, it is necessarY
to improve the extent to which it is possible to realize higher caPacities.
For example, as proposals that high caPacitY be achieved by adjusting the content of elements other than carbon present in the material to optimum levels. Japanese Laid Open Patent Application Numbers 1991-137010 and 1993-74457 disclose car-bonaceous materials containing the element Phosphorus, and Japanese Laid Open Patent APPI ica-tion Number 1991-245458 discloses a carbonaceous material containing boron, United States Patent Number 5,326,658 discloses as an anode a material having a high capacity comPriSing a car-bonaceous material containing nitrogen made by the calcination of an organic Precursor compound ob-tained by reacting a coniugated PolycYclic comPound with a nitrocomPound or a nitrating agent, and Japanese Laid Open Patent APPI ication Number 1992-278751 discloses a sulfur containing carbonaceous anode material.
-2- ~2~7~
- However, to realize the potential of an anode material for high capacity during use in a battery to the same extent that it has been realized for these carbonaceous materials when they are used as simple electrodes, it is necessary to reduce or eliminate the capacity loss during the initial charge discharge cycle. In the case where the cathode is made from a compound in which lithium can be stored such as, for example, LiCoO2, to make the anode from carbonaceous materials it is necessary to charge the battery after assembly and at this time the capacity loss is considerable and the amount of usable lithium decreases making it impossible to achieve a battery having a desirably large capacity.
One solution to the problem of supplying lithium to cover the loss is to include the amount of lithium expected to be lost in the carbonaceous material. For example, before assembling the battery, it is possible to absorb the lithium into the carbon-aceous material electrochemically, or, to attach metallic lithium to the carbonaceous material to be placed in the battery before battery assembly according to the method disclosed in Japanese Laid Open Patent Application Number 1985-235372. Additionally, Japanese Laid Open Patent Application Number 1993-67468 proposes a method for making an anode by mixing powdered carbonaceous material and lithium metal powder under a protective gas or under a vacuum. Additionally, there are the methods of impregnating the carbonaceous material with an organo-lithium compound such as n-butyl lithium and then heating it to obtain the anode material or the method of Japanese Laid Open Patent Application Number ~ 7 4 ~ 71571-8 ~1993-258743 in which impregnation of the carbonaceous material is carried out with a lithium halide solution followed by heat treatment to obtain the anode material. However, in each of these methods, it is either necessary to perform the procedures under an atmosphere of inert gas or to increase the number of steps in the procedure. For this reason, these methods are not advantageous from the standpoint of production. Additionally, the use of dangerous organo-lithium compounds is undesirable from the standpoint of safety.
As stated above, it is necessary to overcome the problem of inadequate capacity or capacity loss experienced with the carbonaceous materials of the prior art with a minimum of added apparatus or additional process steps. The objective of the present invention is to solve the problems of the prior art and by so doing to offer a high performance lithium secondary battery that has greater capacity, improved charge-discharge cycle characteristics and superior stability and safety.
The inventors of the present invention, to achieve the objectives stated above, attempted to conduct their investigation by ad~usting the calcination temperature, degree of crystallinity, and particle surface area of the carbonaceous anode material.
However, they were not able by doing so to achieve any improvement in the extent of capacity loss that would permit the battery to substantially maintain its capacity.
Then, when the inventors of the present invention calcined a lithium containing compound obtained by adding a lithium salt, ~, 3 7 4 ~
~ -4-~ such as lithium carbonate, to a precursor organic compound such as pitch, they observed a great improvement in the capacity of the carbonaceous material obtained. In particular, when they calcined mixtures of lithium salts with the reaction products of such conjugated polycyclic compounds as are described in United States Patent Number 5,326,658 and nitro compounds or nitrating agents, they obtained large battery capacity and a decrease in capacity loss. By using the carbonaceous material thus obtained as an anode material, the inventors of the present invention were able to achieve the objective of making a high performance lithium secondary battery.
The present invention provides an anode material used in the lithium secondary battery made of a carbonaceous material prepared by calcining a lithium containing compound obtained by adding lithium salts to a precursor organic compound.
The present invention also provides a lithium secondary battery employing the anode material and a process for producing the anode material.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The precursor organic compound of the present invention may be an organic polymer or a conjugated polycyclic compound.
The organic polymer may be a phenolic resin, a novolak resin, a furfuryl alcohol resin or the like. The conjugated polycyclic hydrocarbon may be a conjugated polycyclic hydrocarbon such as naphthalene, anthracene, pyrene, coronene or the like or their derivatives; a conjugated heteropolycyclic compound such as benzofuran, quinoline, thionaphthalene, silanaphthalene or their ~ 4a- ~ 7 4 S
derivatives, compounds derlved by linking any of the foregoing compounds together; or, additionally, tars, synthetic pitch, coal tar pitch, petroleum pitch, cokes, petroleum or related heavy oils that are composed partially or completely of or contain the foregoing compounds or mixtures thereof. Pitch or tar having a softening point of 170~C or less are preferred as the conjugated polycyclic compound. Optimization of conditions and pretreat-212~7~
ment depending uPon the kind of coniugated polycY-clic comPound are also desirable. For examPle.
where naPhthalene is used, it is desirable to synthesize pitch or tar from the naPhthalene using HF and BF3 as a catalyst.
Since a carbonaceous material having a large capacity can be obtained therefrom, a precursor organic compound obtained from the reaction of a coniugated polycyclic comPound with a nitrocompound or a nitrating agent as disclosed in United States Patent Number 5,326,65~ is~particularlY
preferred.
As the nitrocompound of the Present invention, aromatic nitrates are Preferred, and dinitro-naphthalene is particularly preferred. The ratioof the weight of the nitrocomPound to the weight of the coniugated polycyclic compound to be used should be selected bY finding the optimum values for the reactants concerned. However, for dinitro-naphthalene and pitch, the preferred ratio isroughly from 0.1 to 3, and, in the case of dinitro-naphthalene and tar, the preferred ratio is roughlY
from 0.05 to 2. The temperature of reaction for the nitrocompound and the coniugated polycyclic comPound should be the optimum reaction temperature for the particular reactants concerned. These oPtimum values generallY fall within the range of 200~C to 600~C.
For the nitration reactions using nitrating agents, the usual reactions for nitration of organ-ic compounds maY be used. For examPle, nitration may be conducted bY the addition of a mixture of concentrated nitric acid and concentrated sulfuric acid or a mixture of concentrated nitric acid and acetic anhYdride or the like. Where a mixture of concentrated nitric acid and concentrated sulfuric acid is used, the ratio of the weight of the ni-2I2~71~
trating agent to the weight of the coniugatedpolycyclic compound is roughlY from 5:1 to 100:1, and the reaction temperature is usuallY from 50~C
to 80~C. Moreover. nitration may also be conducted using a mixture of nitrogen dioxide gas and oxygen or air containing ozone. The nitrated product obtained is washed with water to remove the acid and is then dried.
The ratio of the number of nitrogen atoms to the number of carbon atoms (N/C) and the number of nitrogen atoms to the ~umb'er of oxYgen atoms (N/0) included in the Precursor organic compound prePared as described above varies dePending upon the comPo-sition of the reactants and the temPerature of reaction. however, usually, the N/C is from 0.01 to 0.3 and N/0 is from 0.1 to 3Ø
The lithium salt maY be any lithium salt which, when added to the organic precursor compound of the Present invention and calcined. achieves an anode material that offers the desired reduction in capacity loss. However. Iithium salts. the anion component of which decomposes completely during calcination leaving no residue of elements other than carbon. oxYgen, hYdrogen or nitrogen in the anode material, such as lithium carbonate, Iithium nitrate, lithium hYdroxide or the like, have proven particularly effective, and lithium carbonate and lithium nitrate are preferred. Lithium carbonate is particularly preferred. The ratio of the weight of lithium salt to coniugated polycyclic comPound should dePend on the characteristics of the resPec-tive reaction comPonents to Produce an anode mate-rial with optimum reduction in capacity loss and this can be determined bY testing. However. usual-lY. the lithium salt is added in an amount of fromabout 1 to 15 Parts by weight per 100 parts bY
weight of coniugated polycYclic compound. The 2I2~7g~
reaction temPeratUre is not particularly limited.
However, it is preferred that it be at or above the decomposition temperature for the particular lithi-um salt used. The method for the addition of the lithium salt to the conjugated polycyclic compound is also not particularly limited. However. since its use results in a desirable greater decrease in capacity loss, the method for addition of the lithium salt to the precursor organic compound in a liquid state or semi-liquid state is preferred. One example of this method is the addition of lithium salts to a mixture of anhY~drous tar or Pi tch with a nitrocompound or nitrating agent which mixture has been heated to a temperature above the softening Point of the tar or pitch. The amount of lithium included in the lithium containing compound is PreferablY from about 0.1 wt% to 5 wt%.
The carbonaceous material for anode use of the present invention is obtained by calcination of the lithium containing compound under an atmosphere of inert gas. The calcination temperature is between 800~C to 1800~C, and preferably 1000~C to 1300~C.
The calcination Period is from 0.1 hour to 50 hours, and more preferably from 1 hour to 5 hours optimally determined based upon the characteristics of the precursor organic compound and other react-ants. The inert gas is preferablY nitrogen and is supplied in a continuous flow that, upon exiting, carries away the waste gas of calcination. In place of the inert gas the Process maY be conducted under a vacuum maY in which case the waste gas is removed as the vacuum is maintained.
The carbonaceous material thus obtained contains lithium in amou~ts satisfactory to provide the desired capacity reduction. This usually corre-sponds to a concentration of lithium within the range of from 0.1 wt% to 5 wt% and preferablY
CA 0212874~ 1998-06-0~
within the range of 0.3 wt% to 3 wt% of the anode material.
Moreover, the carbonaceous material obtained where a nitrogen containing compound such as a nitrocompound or the nitrating agent has been added and reacted with the conjugated polycyclic compound, in addition to lithium, contains nitrogen in appropriated amounts.
The appropriate amount is usually within the range of 0.5 wt% to 6 wt% and preferably within the range of from 0.7 wt% to 4 wt%. Additionally, most of this nitrogen, when observed using x-ray photoelectron spectroscopy, occurs in certain specific forms, the bonding of which generates 2 peaks appearing in the vicinity of 399 eV (more precisely within the range of 398.8 + 0.4 eV) and 401 eV (more precisely within the range of 401.2 + 0.2 eV), due to carbon-nitrogen bonding. Of all the bonding involving nitrogen in the anode material of the present invention, 80% or more is represented by the 2 peaks appearing in the vicinity of binding energies corresponding to 399 eV and 401 eV respectively.
The parameters of crystallinity of the carbonaceous material of the present invention depend upon the structural conditions of the material. However, usually, the inter layer spacing (doo2) is 3.4 A or more and the size of the crystallites Lc002 is 70 A or more. The true density is in the range of from 1.4 g/cm3 to 2 g/cm3.
The carbonaceous material of the present invention possesses various excellent properties as anode material, and, in particular, it alleviates the problem of capacity loss.
CA 0212874~ 1998-06-0 -8a-Additionally, the carbonaceous material of the present invention obtained from the reaction of a conjugated polycyclic compound with a nitro~en containing compound such as a nitrocompound or a 2I2~7~
g nitrating agent renders a battery with a capacity of more than 500 (mAh/g) as measured against a lithium potential over an interval of O to 3 volts (V) after a small capacity loss 20 of 100 mAh/g or less.
The construction of the secondarY batterY employ-ing a non-aqueous media of the present invention that uses the aforementioned carbonaceous material as the anode is an anode using the carbonaceous material of the present invention as an anode, and a cathode, separator, non-aqueous electrolyte and casing as describe~d below.
The method of using the carbonaceous material of the Present invention as the anode is not particu-larlY limited.
For example, an electrode maY be prePared bymixing a binder with the powdered anode material of the Present invention, using a solvent where re-quired, and then pressing the electrode material onto a collector after it has been formed into a sheet or bY coating it directlY onto the collector.
Moreover, as the binder, any type of Pi tch maY be used, and the Plate tYPe electrode obtained bY
calcining a mixture of the pitch with the powdered anode material has been used effectivelY. The cathode material is not ParticularlY limited. For example, such lithium containing oxides as LiCoO2, LiNiO2, LiMnO~, LiMn204 and the like, such oxides as TiO2, V20S, MoO3, MnO2, such sulfides as TiS2, FeS, and MoS3 and such selenides as NbSe3, or such con-ductive polYmers as polYacetylene, polYPara-PhenYene, PolYPyrrole and polyaniline or activated carbon may be used. The kind of SeParator that maY be used is not particularly limited. For example, the separator maY be made of synthetic or glass fiber or natural fiber either unwoven or in the form of cloth, and micro Porous resin and the -- 1 o--like may also be used.
In the secondary battery emPloying a non-aqueous media of the present invention either an organic liquid or solid electrolyte may be used. A solu-tion of a lithium salt dissolved in an organicsolvent having a high dielectric constant may be used. The kind of lithium salt that maY be used is not particularly limited. and. for examPle. LiClO4.
LiPF6 or LiSbF6 may be used either singly or as mix-tures of two or more in aPPrOPriate proportions.The organic solvent that maY be used for the elec-trolYte is one that is~abl~e to dissolve the aPPli-cable lithium salt or salts and preferably is non-protic and has a high dielectric content. and ni-triles, carbonates. ethers, nitrocomPounds, sulfurcontaining compounds, chlorinated compounds, ke-tones, esters and the like maY be used. More concretely, for example. acetonitrile, propioni-trile, propylenecarbonate, ethYlenecarbonate, diethylcarbonate, dimethylcarbonate, tetrahydrofur-an, dioxane, 1,2-dimethoxyethane, nitromethane, N, N-dimethylformamide, dimethylsulfoxide, sulfolane, and r-butYrolactone maY be used singlY or in mix-tures of two or more as mixed electrolYtes dePend-ing upon the requirements of the particular situa-tion. The battery casing is usually constructed of stainless steel plate or nickel plated material but maY also be constructed of multi-laYer materi-als constructed from sYnthetic resin and insulating inorganic membranes.
The examples of the Present invention and com-parative exPeriments are recorded below, and the results are concretely and sPecificallY explained.
These examples and comparative experiments are Provided for the Purpose of concrete exPlanation of the present invention and do not in anY way limit the manner in which the present invention may 2I287~
be practiced or the scope of the present invention.
Moreover, the analysis methods and analysis condi-tions for the anode material to be used in the present invention are recorded below.
Particle Size Distribution Measurement The equipment used was a Horiba. Ltd. LA-500 1. Laser Diffraction TyPe Powder Size Distribution Measuring Device.
The measurement was performed by adding 3 droPs of surface active agent to 100 ml of Pure water and then adding the samPle~to~this mixture until it reached a predetermined concentration. After subjecting the samPle to ultrasonic sound wave dispersion for 10 minutes, the measurement was taken and the median diameter obtained was used as the average Particle diameter.
2. Elemental Analysis (excluding lithium) The analytical equipment used was a PERKIN-ELMER
2400 CHN tYPe elemental analYsis device. The measurement was performed by placing 1.5 + 0.2 mg of the test anode material in a small tin cup in the instrument, calcining the samPle at a temPera-ture of 975~C for 5 minutes. The measurement was performed by TCD using helium as the carrier gas.
To establish correspondence between samPle measure-ments and standard test values, the device was calibrated for the sample using acetanilide (2.0 +
0.1 mg~ as the standard.
A LEC0 TC-436 type oXYgen-nitrogen simultaneous analysis device was used in the simultaneous analY-sis of nitrogen and oxYgen. The analysis was carried out by precisely measuring out 10 + 0.5 mg of anode material into a nickel vessel, and after calibrating the equiPment, heating the sample in a graphite crucible by aPPlication of 4800 W of electricitY.
Using helium as the carrier gas, the gas genera-212874~
ted by heating the sample was analYzed by infrared spectroscopy. To establish corresPondence between sample measurements and standard test values, the device was calibrated for the sample using silicon nitride powder having a 1.67% oxygen content (manufactured by Nihon Ceramics Association) as the standard.
3. Elemental AnalYsis: Lithium Analysis of the amount of lithium contained was conducted by means of inductively couPled plasma analysis ~ICP analysis~. ~The equiPment was an SPS-1200 VR tYpe manufactured by Seiko Electronics Industries. PreParation of the sample consisted of reducing the anode material to ash at 900~C in a muffle furnace, dissolving the residue with con-centrated hYdrochloric acid, evaporating the liquid portion of the used washing solution and solidifY-ing the residue, redissolving this residue in lN
aqueous hYdrochloric acid, and then conducting the measurement. An absolute calibration curve was Prepared using standard solutions PrePared using determined amounts of lithium.
However, in resPonse to the trend toward minia-turization of electronic devices, it is necessarY
to improve the extent to which it is possible to realize higher caPacities.
For example, as proposals that high caPacitY be achieved by adjusting the content of elements other than carbon present in the material to optimum levels. Japanese Laid Open Patent Application Numbers 1991-137010 and 1993-74457 disclose car-bonaceous materials containing the element Phosphorus, and Japanese Laid Open Patent APPI ica-tion Number 1991-245458 discloses a carbonaceous material containing boron, United States Patent Number 5,326,658 discloses as an anode a material having a high capacity comPriSing a car-bonaceous material containing nitrogen made by the calcination of an organic Precursor compound ob-tained by reacting a coniugated PolycYclic comPound with a nitrocomPound or a nitrating agent, and Japanese Laid Open Patent APPI ication Number 1992-278751 discloses a sulfur containing carbonaceous anode material.
-2- ~2~7~
- However, to realize the potential of an anode material for high capacity during use in a battery to the same extent that it has been realized for these carbonaceous materials when they are used as simple electrodes, it is necessary to reduce or eliminate the capacity loss during the initial charge discharge cycle. In the case where the cathode is made from a compound in which lithium can be stored such as, for example, LiCoO2, to make the anode from carbonaceous materials it is necessary to charge the battery after assembly and at this time the capacity loss is considerable and the amount of usable lithium decreases making it impossible to achieve a battery having a desirably large capacity.
One solution to the problem of supplying lithium to cover the loss is to include the amount of lithium expected to be lost in the carbonaceous material. For example, before assembling the battery, it is possible to absorb the lithium into the carbon-aceous material electrochemically, or, to attach metallic lithium to the carbonaceous material to be placed in the battery before battery assembly according to the method disclosed in Japanese Laid Open Patent Application Number 1985-235372. Additionally, Japanese Laid Open Patent Application Number 1993-67468 proposes a method for making an anode by mixing powdered carbonaceous material and lithium metal powder under a protective gas or under a vacuum. Additionally, there are the methods of impregnating the carbonaceous material with an organo-lithium compound such as n-butyl lithium and then heating it to obtain the anode material or the method of Japanese Laid Open Patent Application Number ~ 7 4 ~ 71571-8 ~1993-258743 in which impregnation of the carbonaceous material is carried out with a lithium halide solution followed by heat treatment to obtain the anode material. However, in each of these methods, it is either necessary to perform the procedures under an atmosphere of inert gas or to increase the number of steps in the procedure. For this reason, these methods are not advantageous from the standpoint of production. Additionally, the use of dangerous organo-lithium compounds is undesirable from the standpoint of safety.
As stated above, it is necessary to overcome the problem of inadequate capacity or capacity loss experienced with the carbonaceous materials of the prior art with a minimum of added apparatus or additional process steps. The objective of the present invention is to solve the problems of the prior art and by so doing to offer a high performance lithium secondary battery that has greater capacity, improved charge-discharge cycle characteristics and superior stability and safety.
The inventors of the present invention, to achieve the objectives stated above, attempted to conduct their investigation by ad~usting the calcination temperature, degree of crystallinity, and particle surface area of the carbonaceous anode material.
However, they were not able by doing so to achieve any improvement in the extent of capacity loss that would permit the battery to substantially maintain its capacity.
Then, when the inventors of the present invention calcined a lithium containing compound obtained by adding a lithium salt, ~, 3 7 4 ~
~ -4-~ such as lithium carbonate, to a precursor organic compound such as pitch, they observed a great improvement in the capacity of the carbonaceous material obtained. In particular, when they calcined mixtures of lithium salts with the reaction products of such conjugated polycyclic compounds as are described in United States Patent Number 5,326,658 and nitro compounds or nitrating agents, they obtained large battery capacity and a decrease in capacity loss. By using the carbonaceous material thus obtained as an anode material, the inventors of the present invention were able to achieve the objective of making a high performance lithium secondary battery.
The present invention provides an anode material used in the lithium secondary battery made of a carbonaceous material prepared by calcining a lithium containing compound obtained by adding lithium salts to a precursor organic compound.
The present invention also provides a lithium secondary battery employing the anode material and a process for producing the anode material.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The precursor organic compound of the present invention may be an organic polymer or a conjugated polycyclic compound.
The organic polymer may be a phenolic resin, a novolak resin, a furfuryl alcohol resin or the like. The conjugated polycyclic hydrocarbon may be a conjugated polycyclic hydrocarbon such as naphthalene, anthracene, pyrene, coronene or the like or their derivatives; a conjugated heteropolycyclic compound such as benzofuran, quinoline, thionaphthalene, silanaphthalene or their ~ 4a- ~ 7 4 S
derivatives, compounds derlved by linking any of the foregoing compounds together; or, additionally, tars, synthetic pitch, coal tar pitch, petroleum pitch, cokes, petroleum or related heavy oils that are composed partially or completely of or contain the foregoing compounds or mixtures thereof. Pitch or tar having a softening point of 170~C or less are preferred as the conjugated polycyclic compound. Optimization of conditions and pretreat-212~7~
ment depending uPon the kind of coniugated polycY-clic comPound are also desirable. For examPle.
where naPhthalene is used, it is desirable to synthesize pitch or tar from the naPhthalene using HF and BF3 as a catalyst.
Since a carbonaceous material having a large capacity can be obtained therefrom, a precursor organic compound obtained from the reaction of a coniugated polycyclic comPound with a nitrocompound or a nitrating agent as disclosed in United States Patent Number 5,326,65~ is~particularlY
preferred.
As the nitrocompound of the Present invention, aromatic nitrates are Preferred, and dinitro-naphthalene is particularly preferred. The ratioof the weight of the nitrocomPound to the weight of the coniugated polycyclic compound to be used should be selected bY finding the optimum values for the reactants concerned. However, for dinitro-naphthalene and pitch, the preferred ratio isroughly from 0.1 to 3, and, in the case of dinitro-naphthalene and tar, the preferred ratio is roughlY
from 0.05 to 2. The temperature of reaction for the nitrocompound and the coniugated polycyclic comPound should be the optimum reaction temperature for the particular reactants concerned. These oPtimum values generallY fall within the range of 200~C to 600~C.
For the nitration reactions using nitrating agents, the usual reactions for nitration of organ-ic compounds maY be used. For examPle, nitration may be conducted bY the addition of a mixture of concentrated nitric acid and concentrated sulfuric acid or a mixture of concentrated nitric acid and acetic anhYdride or the like. Where a mixture of concentrated nitric acid and concentrated sulfuric acid is used, the ratio of the weight of the ni-2I2~71~
trating agent to the weight of the coniugatedpolycyclic compound is roughlY from 5:1 to 100:1, and the reaction temperature is usuallY from 50~C
to 80~C. Moreover. nitration may also be conducted using a mixture of nitrogen dioxide gas and oxygen or air containing ozone. The nitrated product obtained is washed with water to remove the acid and is then dried.
The ratio of the number of nitrogen atoms to the number of carbon atoms (N/C) and the number of nitrogen atoms to the ~umb'er of oxYgen atoms (N/0) included in the Precursor organic compound prePared as described above varies dePending upon the comPo-sition of the reactants and the temPerature of reaction. however, usually, the N/C is from 0.01 to 0.3 and N/0 is from 0.1 to 3Ø
The lithium salt maY be any lithium salt which, when added to the organic precursor compound of the Present invention and calcined. achieves an anode material that offers the desired reduction in capacity loss. However. Iithium salts. the anion component of which decomposes completely during calcination leaving no residue of elements other than carbon. oxYgen, hYdrogen or nitrogen in the anode material, such as lithium carbonate, Iithium nitrate, lithium hYdroxide or the like, have proven particularly effective, and lithium carbonate and lithium nitrate are preferred. Lithium carbonate is particularly preferred. The ratio of the weight of lithium salt to coniugated polycyclic comPound should dePend on the characteristics of the resPec-tive reaction comPonents to Produce an anode mate-rial with optimum reduction in capacity loss and this can be determined bY testing. However. usual-lY. the lithium salt is added in an amount of fromabout 1 to 15 Parts by weight per 100 parts bY
weight of coniugated polycYclic compound. The 2I2~7g~
reaction temPeratUre is not particularly limited.
However, it is preferred that it be at or above the decomposition temperature for the particular lithi-um salt used. The method for the addition of the lithium salt to the conjugated polycyclic compound is also not particularly limited. However. since its use results in a desirable greater decrease in capacity loss, the method for addition of the lithium salt to the precursor organic compound in a liquid state or semi-liquid state is preferred. One example of this method is the addition of lithium salts to a mixture of anhY~drous tar or Pi tch with a nitrocompound or nitrating agent which mixture has been heated to a temperature above the softening Point of the tar or pitch. The amount of lithium included in the lithium containing compound is PreferablY from about 0.1 wt% to 5 wt%.
The carbonaceous material for anode use of the present invention is obtained by calcination of the lithium containing compound under an atmosphere of inert gas. The calcination temperature is between 800~C to 1800~C, and preferably 1000~C to 1300~C.
The calcination Period is from 0.1 hour to 50 hours, and more preferably from 1 hour to 5 hours optimally determined based upon the characteristics of the precursor organic compound and other react-ants. The inert gas is preferablY nitrogen and is supplied in a continuous flow that, upon exiting, carries away the waste gas of calcination. In place of the inert gas the Process maY be conducted under a vacuum maY in which case the waste gas is removed as the vacuum is maintained.
The carbonaceous material thus obtained contains lithium in amou~ts satisfactory to provide the desired capacity reduction. This usually corre-sponds to a concentration of lithium within the range of from 0.1 wt% to 5 wt% and preferablY
CA 0212874~ 1998-06-0~
within the range of 0.3 wt% to 3 wt% of the anode material.
Moreover, the carbonaceous material obtained where a nitrogen containing compound such as a nitrocompound or the nitrating agent has been added and reacted with the conjugated polycyclic compound, in addition to lithium, contains nitrogen in appropriated amounts.
The appropriate amount is usually within the range of 0.5 wt% to 6 wt% and preferably within the range of from 0.7 wt% to 4 wt%. Additionally, most of this nitrogen, when observed using x-ray photoelectron spectroscopy, occurs in certain specific forms, the bonding of which generates 2 peaks appearing in the vicinity of 399 eV (more precisely within the range of 398.8 + 0.4 eV) and 401 eV (more precisely within the range of 401.2 + 0.2 eV), due to carbon-nitrogen bonding. Of all the bonding involving nitrogen in the anode material of the present invention, 80% or more is represented by the 2 peaks appearing in the vicinity of binding energies corresponding to 399 eV and 401 eV respectively.
The parameters of crystallinity of the carbonaceous material of the present invention depend upon the structural conditions of the material. However, usually, the inter layer spacing (doo2) is 3.4 A or more and the size of the crystallites Lc002 is 70 A or more. The true density is in the range of from 1.4 g/cm3 to 2 g/cm3.
The carbonaceous material of the present invention possesses various excellent properties as anode material, and, in particular, it alleviates the problem of capacity loss.
CA 0212874~ 1998-06-0 -8a-Additionally, the carbonaceous material of the present invention obtained from the reaction of a conjugated polycyclic compound with a nitro~en containing compound such as a nitrocompound or a 2I2~7~
g nitrating agent renders a battery with a capacity of more than 500 (mAh/g) as measured against a lithium potential over an interval of O to 3 volts (V) after a small capacity loss 20 of 100 mAh/g or less.
The construction of the secondarY batterY employ-ing a non-aqueous media of the present invention that uses the aforementioned carbonaceous material as the anode is an anode using the carbonaceous material of the present invention as an anode, and a cathode, separator, non-aqueous electrolyte and casing as describe~d below.
The method of using the carbonaceous material of the Present invention as the anode is not particu-larlY limited.
For example, an electrode maY be prePared bymixing a binder with the powdered anode material of the Present invention, using a solvent where re-quired, and then pressing the electrode material onto a collector after it has been formed into a sheet or bY coating it directlY onto the collector.
Moreover, as the binder, any type of Pi tch maY be used, and the Plate tYPe electrode obtained bY
calcining a mixture of the pitch with the powdered anode material has been used effectivelY. The cathode material is not ParticularlY limited. For example, such lithium containing oxides as LiCoO2, LiNiO2, LiMnO~, LiMn204 and the like, such oxides as TiO2, V20S, MoO3, MnO2, such sulfides as TiS2, FeS, and MoS3 and such selenides as NbSe3, or such con-ductive polYmers as polYacetylene, polYPara-PhenYene, PolYPyrrole and polyaniline or activated carbon may be used. The kind of SeParator that maY be used is not particularly limited. For example, the separator maY be made of synthetic or glass fiber or natural fiber either unwoven or in the form of cloth, and micro Porous resin and the -- 1 o--like may also be used.
In the secondary battery emPloying a non-aqueous media of the present invention either an organic liquid or solid electrolyte may be used. A solu-tion of a lithium salt dissolved in an organicsolvent having a high dielectric constant may be used. The kind of lithium salt that maY be used is not particularly limited. and. for examPle. LiClO4.
LiPF6 or LiSbF6 may be used either singly or as mix-tures of two or more in aPPrOPriate proportions.The organic solvent that maY be used for the elec-trolYte is one that is~abl~e to dissolve the aPPli-cable lithium salt or salts and preferably is non-protic and has a high dielectric content. and ni-triles, carbonates. ethers, nitrocomPounds, sulfurcontaining compounds, chlorinated compounds, ke-tones, esters and the like maY be used. More concretely, for example. acetonitrile, propioni-trile, propylenecarbonate, ethYlenecarbonate, diethylcarbonate, dimethylcarbonate, tetrahydrofur-an, dioxane, 1,2-dimethoxyethane, nitromethane, N, N-dimethylformamide, dimethylsulfoxide, sulfolane, and r-butYrolactone maY be used singlY or in mix-tures of two or more as mixed electrolYtes dePend-ing upon the requirements of the particular situa-tion. The battery casing is usually constructed of stainless steel plate or nickel plated material but maY also be constructed of multi-laYer materi-als constructed from sYnthetic resin and insulating inorganic membranes.
The examples of the Present invention and com-parative exPeriments are recorded below, and the results are concretely and sPecificallY explained.
These examples and comparative experiments are Provided for the Purpose of concrete exPlanation of the present invention and do not in anY way limit the manner in which the present invention may 2I287~
be practiced or the scope of the present invention.
Moreover, the analysis methods and analysis condi-tions for the anode material to be used in the present invention are recorded below.
Particle Size Distribution Measurement The equipment used was a Horiba. Ltd. LA-500 1. Laser Diffraction TyPe Powder Size Distribution Measuring Device.
The measurement was performed by adding 3 droPs of surface active agent to 100 ml of Pure water and then adding the samPle~to~this mixture until it reached a predetermined concentration. After subjecting the samPle to ultrasonic sound wave dispersion for 10 minutes, the measurement was taken and the median diameter obtained was used as the average Particle diameter.
2. Elemental Analysis (excluding lithium) The analytical equipment used was a PERKIN-ELMER
2400 CHN tYPe elemental analYsis device. The measurement was performed by placing 1.5 + 0.2 mg of the test anode material in a small tin cup in the instrument, calcining the samPle at a temPera-ture of 975~C for 5 minutes. The measurement was performed by TCD using helium as the carrier gas.
To establish correspondence between samPle measure-ments and standard test values, the device was calibrated for the sample using acetanilide (2.0 +
0.1 mg~ as the standard.
A LEC0 TC-436 type oXYgen-nitrogen simultaneous analysis device was used in the simultaneous analY-sis of nitrogen and oxYgen. The analysis was carried out by precisely measuring out 10 + 0.5 mg of anode material into a nickel vessel, and after calibrating the equiPment, heating the sample in a graphite crucible by aPPlication of 4800 W of electricitY.
Using helium as the carrier gas, the gas genera-212874~
ted by heating the sample was analYzed by infrared spectroscopy. To establish corresPondence between sample measurements and standard test values, the device was calibrated for the sample using silicon nitride powder having a 1.67% oxygen content (manufactured by Nihon Ceramics Association) as the standard.
3. Elemental AnalYsis: Lithium Analysis of the amount of lithium contained was conducted by means of inductively couPled plasma analysis ~ICP analysis~. ~The equiPment was an SPS-1200 VR tYpe manufactured by Seiko Electronics Industries. PreParation of the sample consisted of reducing the anode material to ash at 900~C in a muffle furnace, dissolving the residue with con-centrated hYdrochloric acid, evaporating the liquid portion of the used washing solution and solidifY-ing the residue, redissolving this residue in lN
aqueous hYdrochloric acid, and then conducting the measurement. An absolute calibration curve was Prepared using standard solutions PrePared using determined amounts of lithium.
4. X-ray Photoelectron SPectroscopY Analysis The equipment used was a V. G. Scientific ESCALAB
MK-II. The analysis was Performed using Mg-Ka as the x-raY source at 15 KV - 20 mA and using an A1 slit (2 X 5 mm). PreParation for analYsis consist-ed of Placing the sample on double sided tape.
Measurement was conducted with the sample in this condition, or, in some cases, after argon etching of the samPle surface. The analysis was performed by measuring each Peak Precisely within a narrow range after first measuring all of the peaks over a broad range and identifying individual peaks. The charge uP correction was made by setting the ob-served carbon 1s energy ("C-1s") at 284.4 eV and adiusting the value for each peak accordinglY.
212~7~5 True density was determined by the float and sink method using a carbon tetrachloride-bromoform mixture at 25~C.
EXAMPLE 1.
Twenty parts by weight of dinitronaphthalene were added to 80 parts bY weight of tar (manufactured by Kawasaki Steel CompanY~ and 5 parts bY weisht of lithium carbonate at 100~C, the temPerature was raised to 400~C while mixi~rg the three together and a lithium containing compound that was 1.2 wt%
lithium was obtained. This compound was powdered using a ball mill. The black powder thus obtained was then calcined for 2 hours at 1000~C under a stream of nitrogen gas to obtain the powdered anode material. This anode material contained 1.6 wt% of lithium. Moreover. the nitrogen content of this anode material was 0.91 wt% of nitrogen, and the result of XPS measurement was 2 peaks representing binding energies of 401.4 eV and 398.6 eV having an intensity ratio (the intensitY of the 401.4 eV
Peak/ the intensity of the 398.6 eV peak) of 2.5 which peaks accounted for 100% of the bonding involving nitrogen observed in the anode material.
A flexible shaped article for use as a test elec-trode was Prepared by mixing 100 parts bY weight of the powdered anode material thus obtained with 5 parts by weight of polytetrafluoroethylene (binder) and compressing them into a round disk. A half cell was PrePared using this test electrode, ac-cording to the usual methods, using LiC104 dissolved in a solvent composed of an equal volume mixture of propylene carbonate and 1.2-dimethoxYethane (concentration of LiClOq 1.0 mol/l) PrePared as an electroIyte and using a seParator made from a porous polypropylene membrane with a thickness of ~ 21287~5 50 ~m. As the counter electrode, a 16 mm diameter, 0.5 mm thick disk of lithium metal was used. A
small piece of lithium metal similar to the counter electrode was used as the reference electrode.
The first cycle circuit potential of the half cell obtained above was 3.18 V (volts). Subse-quently, the half cell was charged at a constant current density of 1.0 mA/cm2 until there was no change in the potential of the test electrode with respect to the reference electrode. The charge capacity was 601 mAh/g< Then, the half cell was discharged at a constant current density of 1.0 mA/cm2, and by the time the electrode reached 0.1 V, the observed discharge capacity was 249 mAh/g, by the time the electrode potential reached 0.5V. the observed discharge capacity was 386 mAh/g and finally, when discharging had proceeded sufficient-ly for the electrode potential to reach 3.0 V, the observed discharge caPacitY was 522 mAh/g. The charge-discharge capacity loss was 79 mAh/g.
Evaluation of the Secondary Battery A test electrode with a thickness of 0.3 mm, a diameter of 15 mm and a weight of 90 mg prepared bY
the same methods as the above test electrode was used as the anode, and using LiC104 dissolved in a solvent composed of an equal volume mixture of propylene carbonate and 1,2-dimethoxYethane (LiCl04:
l.0 mol/l) prepared as an electrolyte and using a separator made from a porous polypropylene membrane with a thickness of 50 ~m, a secondary battery was prepared, The cathode was Prepared by mixing 85 parts bY weight of LiCoO2 with 10 Parts by weight of acetylene black (conducting agent) and 5 parts bY weight of polYtetrafluor-oethylene (binder) and compressing the mixture intoa disk (weight 250 mg and diameter 14 mm).
The circuit voltage for the initial cycle of the 212871~
,, secondary battery thus obtained was 0.03 V. When, after charging at a constant current until the charging voltage at a current densitY of 1.0 mA/cm2 reached 4.10 V, the battery was then discharged at a constant current until the charging voltage at a current density of 1.0 mA/cm2. an initial Period charge capacity of 36.0 mAh and an initial dis-charge capacity of 31.3 mAh were observed. Subse-quently, when a constant current charge-discharge cYcle exPeriment was performed with the lower voltage limit set at 2.00~V, the upper voltage limit set at 4.10 V and the current densitY set at 1.0 mA/cm2, discharge capacities of 30.7 mAh after 40 cycles, 30.5 mAh after 250 cYcles and 30.2 mAh after 500 cycles were observed. Moreover, up to 500 cycles, the average discharge voltage of the battery was 3.6 V or more.
Except that no lithium carbonate was added ac-cording to the method disclosed in Exa~ple 1, a powdered anode material was obtained by the same methods and using the same materials as in Example 1. The elemental analysis of the anode material thus obtained for nitrogen was 0.91 wt%. Moreover, according to XPS analysis, 2 peaks based on binding energies of 398.6 eV and 401.4 eV were observed.
The ratio of the intensities of these 2 peaks was (the intensity of the 401.4 eV peak/ the intensity of the 398.6 eV Peak) 2.5, and these 2 peaks ac-counted for 100% of all bonding involving nitrogen in the anode material.
A test electrode was prepared bY sintering a test electrode disk as in Example 1 and when a charge discharge experiment was conducted at constant voltage, the charge capacity was 596 mAh/g. Subse-2i~87~
quently, using this test electrode, a half cell was prepared as in example 1 and charge-discharge experiments were conducted at constant current. By the time the electrode potential reached 0.1 V, the observed discharge capacity was 237 mAh/g. By the time the electrode potential reached 0.5 V, the ob-served discharge capaCitY was 367 mAh/g and by the time it had reached 3.0 V, the discharge capacity was 496 m-Ah/g. The charge-discharge caPacitY loss was 109 mAh/g. Next, a secondarY battery was prepared using the same methods as in Example 1, except for the use of the anode material obtained above. When charge-discharge experiments were conducted at constant voltage, the initial period circuit voltage was 0.03 V, the initial period charging capacity was 35.7 mAh and the initial period discharge capacity was 29.7 mAh.
EXAMPLE 2.
One mole of naphthalene, 0.5 moles of HF, and 0.5 moles of BF3 were mixed in an acid resistant auto clave with a 500 ml capacity, and, after the tem-perature was raised to 200~C and the pressure of the gas was raised to 25 kg/cm~, the reaction was conducted at this temPerature and pressure over a period of two hours. SubsequentlY, nitrogen gas was introduced into the autoclave bY the usual methods. This introduction of nitrogen gas also caused the recoverY of HF and BF3. BY further removal of low boiling point components, a pitch with a softening point of about 115~C was obtained.
At a temPerature of 120~C, 10 parts by weight of lithium carbonate and 100 parts by weight of dini-tronaphthalene were mixed with 100 parts by weightof the pitch having a softening Point of 115~C
obtained in this way, after which, the temperature , ,.,., 2I287~ .
of the mixture was raised to 270~C until the reac-tion was completed. The mixture thus heated was cooled and then ground to a powder in a ball mill.
and the powder thus obtained was heated at 1000~C
for 2 hours under a stream of nitrogen gas to obtain a powdered anode material.
The amount of lithium contained in the anode material thus obtained was 1.4 wt% and the amount of nitrogen contained was 1.67 wt%. Two peaks based on N-1s with bind,ing.~energies of 398.6 eV and 401.4 eV were observed by XPS analysis of the anode material. The ratio of the intensities of these two peaks (the intensity of the 401.4 eV peak/the intensity of the 398.6 eV peak) was 2.5. and the two peaks accounted for 100% of the total bonding involving nitrogen.
Moreover, when a half cell and a secondary bat-tery were PrePared as in ExamPle 1 using the mate-rial Prepared in this Example 2 and charge - dis-charge experiments were conducted at constantcurrent, essentially the same results were obtained in terms of capacity loss improvement as in Example 1.
EXAMPLE 3.
Except for the use coal tar pitch having a sof-tening temperature of 110~C (manufactured bY
ADCHEMC0 CorPoration) in place of the pitch ob-tained by the methods of Example 2, a half cell anda battery were prepared using the same materials and by the same methods as in Example 2, and, when charge - discharge eXPerimentS were conducted at constant current, essentially the same results in terms of caPacitY loss improvement were obtained as in Example 1.
212~7~
. ..
EFFECTS OF THE PRESENT INVENTION
The desirable properties of the secondarY battery of the present invention, compared uith those of S the Prior art, are less prone to decrease over time, and the secondary batterY of the present invention shows excellent safetY and has excellent charge-discharge characteristics in addition to its large apacity.
., ~
MK-II. The analysis was Performed using Mg-Ka as the x-raY source at 15 KV - 20 mA and using an A1 slit (2 X 5 mm). PreParation for analYsis consist-ed of Placing the sample on double sided tape.
Measurement was conducted with the sample in this condition, or, in some cases, after argon etching of the samPle surface. The analysis was performed by measuring each Peak Precisely within a narrow range after first measuring all of the peaks over a broad range and identifying individual peaks. The charge uP correction was made by setting the ob-served carbon 1s energy ("C-1s") at 284.4 eV and adiusting the value for each peak accordinglY.
212~7~5 True density was determined by the float and sink method using a carbon tetrachloride-bromoform mixture at 25~C.
EXAMPLE 1.
Twenty parts by weight of dinitronaphthalene were added to 80 parts bY weight of tar (manufactured by Kawasaki Steel CompanY~ and 5 parts bY weisht of lithium carbonate at 100~C, the temPerature was raised to 400~C while mixi~rg the three together and a lithium containing compound that was 1.2 wt%
lithium was obtained. This compound was powdered using a ball mill. The black powder thus obtained was then calcined for 2 hours at 1000~C under a stream of nitrogen gas to obtain the powdered anode material. This anode material contained 1.6 wt% of lithium. Moreover. the nitrogen content of this anode material was 0.91 wt% of nitrogen, and the result of XPS measurement was 2 peaks representing binding energies of 401.4 eV and 398.6 eV having an intensity ratio (the intensitY of the 401.4 eV
Peak/ the intensity of the 398.6 eV peak) of 2.5 which peaks accounted for 100% of the bonding involving nitrogen observed in the anode material.
A flexible shaped article for use as a test elec-trode was Prepared by mixing 100 parts bY weight of the powdered anode material thus obtained with 5 parts by weight of polytetrafluoroethylene (binder) and compressing them into a round disk. A half cell was PrePared using this test electrode, ac-cording to the usual methods, using LiC104 dissolved in a solvent composed of an equal volume mixture of propylene carbonate and 1.2-dimethoxYethane (concentration of LiClOq 1.0 mol/l) PrePared as an electroIyte and using a seParator made from a porous polypropylene membrane with a thickness of ~ 21287~5 50 ~m. As the counter electrode, a 16 mm diameter, 0.5 mm thick disk of lithium metal was used. A
small piece of lithium metal similar to the counter electrode was used as the reference electrode.
The first cycle circuit potential of the half cell obtained above was 3.18 V (volts). Subse-quently, the half cell was charged at a constant current density of 1.0 mA/cm2 until there was no change in the potential of the test electrode with respect to the reference electrode. The charge capacity was 601 mAh/g< Then, the half cell was discharged at a constant current density of 1.0 mA/cm2, and by the time the electrode reached 0.1 V, the observed discharge capacity was 249 mAh/g, by the time the electrode potential reached 0.5V. the observed discharge capacity was 386 mAh/g and finally, when discharging had proceeded sufficient-ly for the electrode potential to reach 3.0 V, the observed discharge caPacitY was 522 mAh/g. The charge-discharge capacity loss was 79 mAh/g.
Evaluation of the Secondary Battery A test electrode with a thickness of 0.3 mm, a diameter of 15 mm and a weight of 90 mg prepared bY
the same methods as the above test electrode was used as the anode, and using LiC104 dissolved in a solvent composed of an equal volume mixture of propylene carbonate and 1,2-dimethoxYethane (LiCl04:
l.0 mol/l) prepared as an electrolyte and using a separator made from a porous polypropylene membrane with a thickness of 50 ~m, a secondary battery was prepared, The cathode was Prepared by mixing 85 parts bY weight of LiCoO2 with 10 Parts by weight of acetylene black (conducting agent) and 5 parts bY weight of polYtetrafluor-oethylene (binder) and compressing the mixture intoa disk (weight 250 mg and diameter 14 mm).
The circuit voltage for the initial cycle of the 212871~
,, secondary battery thus obtained was 0.03 V. When, after charging at a constant current until the charging voltage at a current densitY of 1.0 mA/cm2 reached 4.10 V, the battery was then discharged at a constant current until the charging voltage at a current density of 1.0 mA/cm2. an initial Period charge capacity of 36.0 mAh and an initial dis-charge capacity of 31.3 mAh were observed. Subse-quently, when a constant current charge-discharge cYcle exPeriment was performed with the lower voltage limit set at 2.00~V, the upper voltage limit set at 4.10 V and the current densitY set at 1.0 mA/cm2, discharge capacities of 30.7 mAh after 40 cycles, 30.5 mAh after 250 cYcles and 30.2 mAh after 500 cycles were observed. Moreover, up to 500 cycles, the average discharge voltage of the battery was 3.6 V or more.
Except that no lithium carbonate was added ac-cording to the method disclosed in Exa~ple 1, a powdered anode material was obtained by the same methods and using the same materials as in Example 1. The elemental analysis of the anode material thus obtained for nitrogen was 0.91 wt%. Moreover, according to XPS analysis, 2 peaks based on binding energies of 398.6 eV and 401.4 eV were observed.
The ratio of the intensities of these 2 peaks was (the intensity of the 401.4 eV peak/ the intensity of the 398.6 eV Peak) 2.5, and these 2 peaks ac-counted for 100% of all bonding involving nitrogen in the anode material.
A test electrode was prepared bY sintering a test electrode disk as in Example 1 and when a charge discharge experiment was conducted at constant voltage, the charge capacity was 596 mAh/g. Subse-2i~87~
quently, using this test electrode, a half cell was prepared as in example 1 and charge-discharge experiments were conducted at constant current. By the time the electrode potential reached 0.1 V, the observed discharge capacity was 237 mAh/g. By the time the electrode potential reached 0.5 V, the ob-served discharge capaCitY was 367 mAh/g and by the time it had reached 3.0 V, the discharge capacity was 496 m-Ah/g. The charge-discharge caPacitY loss was 109 mAh/g. Next, a secondarY battery was prepared using the same methods as in Example 1, except for the use of the anode material obtained above. When charge-discharge experiments were conducted at constant voltage, the initial period circuit voltage was 0.03 V, the initial period charging capacity was 35.7 mAh and the initial period discharge capacity was 29.7 mAh.
EXAMPLE 2.
One mole of naphthalene, 0.5 moles of HF, and 0.5 moles of BF3 were mixed in an acid resistant auto clave with a 500 ml capacity, and, after the tem-perature was raised to 200~C and the pressure of the gas was raised to 25 kg/cm~, the reaction was conducted at this temPerature and pressure over a period of two hours. SubsequentlY, nitrogen gas was introduced into the autoclave bY the usual methods. This introduction of nitrogen gas also caused the recoverY of HF and BF3. BY further removal of low boiling point components, a pitch with a softening point of about 115~C was obtained.
At a temPerature of 120~C, 10 parts by weight of lithium carbonate and 100 parts by weight of dini-tronaphthalene were mixed with 100 parts by weightof the pitch having a softening Point of 115~C
obtained in this way, after which, the temperature , ,.,., 2I287~ .
of the mixture was raised to 270~C until the reac-tion was completed. The mixture thus heated was cooled and then ground to a powder in a ball mill.
and the powder thus obtained was heated at 1000~C
for 2 hours under a stream of nitrogen gas to obtain a powdered anode material.
The amount of lithium contained in the anode material thus obtained was 1.4 wt% and the amount of nitrogen contained was 1.67 wt%. Two peaks based on N-1s with bind,ing.~energies of 398.6 eV and 401.4 eV were observed by XPS analysis of the anode material. The ratio of the intensities of these two peaks (the intensity of the 401.4 eV peak/the intensity of the 398.6 eV peak) was 2.5. and the two peaks accounted for 100% of the total bonding involving nitrogen.
Moreover, when a half cell and a secondary bat-tery were PrePared as in ExamPle 1 using the mate-rial Prepared in this Example 2 and charge - dis-charge experiments were conducted at constantcurrent, essentially the same results were obtained in terms of capacity loss improvement as in Example 1.
EXAMPLE 3.
Except for the use coal tar pitch having a sof-tening temperature of 110~C (manufactured bY
ADCHEMC0 CorPoration) in place of the pitch ob-tained by the methods of Example 2, a half cell anda battery were prepared using the same materials and by the same methods as in Example 2, and, when charge - discharge eXPerimentS were conducted at constant current, essentially the same results in terms of caPacitY loss improvement were obtained as in Example 1.
212~7~
. ..
EFFECTS OF THE PRESENT INVENTION
The desirable properties of the secondarY battery of the present invention, compared uith those of S the Prior art, are less prone to decrease over time, and the secondary batterY of the present invention shows excellent safetY and has excellent charge-discharge characteristics in addition to its large apacity.
., ~
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A lithium secondary battery comprising a non-aqueous electrolyte and an anode of a carbonaceous material prepared by a calcination of a lithium containing compound obtained by adding a lithium salt to a precursor organic compound, the calcination being conducted in an atmosphere of an inert gas or in a vacuum at 800°C to 1,800°C for 0.1 to 50 hours.
2. A lithium secondary battery according to claim 1, wherein the lithium containing compound contains from 0.1 wt%
to 5 wt% of lithium.
to 5 wt% of lithium.
3. A lithium secondary battery according to claim 1, wherein the precursor organic compound is obtained by reacting at least one conjugated polycyclic organic compound with a nitro compound or with a nitrating agent.
4. A lithium secondary battery according to claim 3, wherein the polycyclic organic compound is tar or pitch having a softening point of 170°C or less.
5. A lithium secondary battery according to claim 3, wherein the nitro compound is an aromatic nitrate.
6. A lithium secondary battery according to claim 5, wherein the aromatic nitrate is dinitronaphthalene.
7. A lithium secondary battery according to claim 1, 2, 3, 4, 5 or 6, wherein the anode material is prepared by calcining the lithium containing compound at from 1,000°C to 1,300°.
8. A lithium secondary battery according to claim 1, 2, 3, 4, 5 or 6, wherein the anode material contains nitrogen atoms and from 0.1 wt% to 5 wt% of lithium atoms, where the amount of the nitrogen atoms contained is between 0.5 wt% and 6 wt%, and 80% or more of the nitrogen atoms are in carbon-nitrogen single bonds (C-N) or carbon-nitroen double bonds (C=N) that give rise to X-ray photo-electron spectroscopy peaks corresponding to bonding energies of 401.2+0.2eV and 398.8+0.4eV, respectively, the ratio of the intensity of which is 1.0 or more.
9. A lithium secondary battery according to claim 1, 2, 3, 4, 5 or 6, which further comprises a casing, a cathode and a separator.
10. An anode for a lithium secondary battery, the anode being made of a carbonaceous material which consists essentially of carbon, oxygen, hydrogen, 0 or 0.5 to 6 wt% of nitrogen and lithium and is prepared by a calcination of a lithium containing compound obtained by adding a lithium salt to a precursor organic compound, wherein the calcination is conducted in an atmosphere of an inert gas or in a vacuum at 800°C to 1,800°C for 0.1 to 50 hours; and lithium is contained in the carbonaceous anode material in an amount sufficient to reduce or eliminate a capacity loss during an initial charge-discharge cycle of the lithium secondary battery.
11. An anode according to claim 10, wherein the carbonaceous anode material contains 0.1 to 5 wt% of lithium atoms and 0.5 to 6 wt% of nitrogen atoms.
12. An anode according to claim 11, wherein at least 80% of the nitrogen atoms are in carbon-nitrogen single bonds (C-N) or carbon-nitrogen double bonds (C=N) that give rise to X-ray photoelectron spectroscopy peaks corresponding to bonding energies of 401.2+0.2eV and 398.8+0.4eV, respectively.
13. An anode according to claim 11, wherein the carbonaceous anode material has an inner layer spacing (d002) of 3.4.ANG. or more, a size of crystallites (LC002) of 70.ANG. or less and a true density of 1.4 to 2 g/cm3.
14. A process for producing the anode as defined in any one of claims 10, 11, 12 or 13, which comprises:
calcining the lithium containing compound obtained by adding a lithium salt to a precursor organic compound at a temperature of from 800°C to 1,800°C in an atmosphere of an inert gas or in a vacuum for 0.1 to 50 hours.
calcining the lithium containing compound obtained by adding a lithium salt to a precursor organic compound at a temperature of from 800°C to 1,800°C in an atmosphere of an inert gas or in a vacuum for 0.1 to 50 hours.
15. A process according to claim 14, wherein the precursor organic compound is at least one member selected from the group consisting of organic polymers, conjugated polycyclic compounds, and reaction products of conjugated polycyclic compounds with nitro compounds or nitrating agents.
16. A process according to claim 15, wherein the lithium salt is at least one member selected from the group consisting of lithium carbonate, lithium nitrate and lithium hydroxide.
17. A process according to claim 16, wherein the precursor organic compound comprises at least one reaction product of a conjugated polycyclic compound with a nitro compound or a nitrating agent.
18. A process according to claim 17, wherein the reaction product is produced by reacting pitch or tar each having a softening point of 170°C or less as the conjugated polycyclic compound with dinitronaphthalene as the nitro compound at a temperature of 200°C to 600°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5184066A JPH0737577A (en) | 1993-07-26 | 1993-07-26 | Improved non-aqueous solvent lithium secondary battery |
| JP5-184066 | 1993-07-26 |
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| CA2128745A1 CA2128745A1 (en) | 1995-01-27 |
| CA2128745C true CA2128745C (en) | 1998-12-08 |
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| CA002128745A Expired - Fee Related CA2128745C (en) | 1993-07-26 | 1994-07-25 | Lithium secondary battery employing a non-aqueous media |
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| Country | Link |
|---|---|
| US (1) | US5679480A (en) |
| EP (1) | EP0637090B1 (en) |
| JP (1) | JPH0737577A (en) |
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| US4835047A (en) * | 1987-05-14 | 1989-05-30 | Avraam Isayev | Wholly aromatic polyester fiber-reinforced polyetherimide composite and process for preparing same |
| US6337159B1 (en) * | 1995-03-07 | 2002-01-08 | Ramot University Authority For Applied Research & Industrial Development Ltd. | Lithium anode with solid electrolyte interface |
| JP3724099B2 (en) * | 1996-02-22 | 2005-12-07 | ソニー株式会社 | Method for producing carbonaceous negative electrode material for non-aqueous electrolyte secondary battery |
| US7041412B2 (en) * | 2001-07-23 | 2006-05-09 | Matsushita Electric Industrial Co., Ltd. | Non-aqueous electrolyte secondary battery |
| DE10212609B4 (en) * | 2002-03-21 | 2015-03-26 | Epcos Ag | Electrolytic solution and its use |
| US7019495B2 (en) | 2003-08-28 | 2006-03-28 | C.E. Neihoff & Co. | Inter-regulator control of multiple electric power sources |
| JP4892838B2 (en) * | 2004-03-01 | 2012-03-07 | 三菱瓦斯化学株式会社 | Carbonized product production method and carbonized product obtained by the method |
| JP4766701B2 (en) * | 2005-09-30 | 2011-09-07 | 旭化成ケミカルズ株式会社 | Nitrogen-containing carbon material and method for producing the same |
| US8092771B2 (en) * | 2007-03-28 | 2012-01-10 | Asahi Kasei Chemicals Corporation | Nitrogen-containing carbon material and process for producing the same |
| US8486565B2 (en) | 2007-03-28 | 2013-07-16 | Asahi Kasei Chemicals Corporation | Electrode, and lithium ion secondary battery, electric double layer capacitor and fuel cell using the same |
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| JPH0789483B2 (en) * | 1984-05-07 | 1995-09-27 | 三洋化成工業株式会社 | Secondary battery |
| DE69008978T2 (en) * | 1989-07-29 | 1994-12-01 | Sony Corp | Carbon material and a non-aqueous electrochemical cell using this material. |
| JP3060474B2 (en) * | 1989-07-29 | 2000-07-10 | ソニー株式会社 | Negative electrode for battery, method for producing the same, and nonaqueous electrolyte battery using the same |
| JP2856795B2 (en) * | 1989-12-05 | 1999-02-10 | 三菱化学株式会社 | Electrodes for secondary batteries |
| JP3060471B2 (en) * | 1990-02-21 | 2000-07-10 | ソニー株式会社 | Negative electrode for battery, method for producing the same, and nonaqueous electrolyte battery using the same |
| DE4101533A1 (en) * | 1991-01-19 | 1992-07-23 | Varta Batterie | ELECTROCHEMICAL SECONDARY ELEMENT |
| JP3318767B2 (en) * | 1991-03-02 | 2002-08-26 | ソニー株式会社 | Negative electrode material, method for producing the same, and nonaqueous electrolyte battery using the same |
| US5294498A (en) * | 1991-03-02 | 1994-03-15 | Sony Corporation | Anode material, method for producing it and non-aqueous electrolyte cell employing such anode materials |
| JPH05258743A (en) * | 1991-11-01 | 1993-10-08 | Sanyo Electric Co Ltd | Lithium secondary battery |
| CA2083001C (en) * | 1991-12-17 | 1996-12-17 | Yuzuru Takahashi | Lithium secondary battery using a non-aqueous solvent |
| JP3187929B2 (en) * | 1992-04-09 | 2001-07-16 | 三洋電機株式会社 | Lithium secondary battery |
| JPH06132031A (en) * | 1992-10-16 | 1994-05-13 | Mitsubishi Gas Chem Co Inc | Improved non-aqueous solvent lithium secondary battery |
-
1993
- 1993-07-26 JP JP5184066A patent/JPH0737577A/en active Pending
-
1994
- 1994-07-21 DE DE69409446T patent/DE69409446T2/en not_active Expired - Fee Related
- 1994-07-21 EP EP94305412A patent/EP0637090B1/en not_active Expired - Lifetime
- 1994-07-21 DE DE0637090T patent/DE637090T1/en active Pending
- 1994-07-25 CA CA002128745A patent/CA2128745C/en not_active Expired - Fee Related
- 1994-07-25 US US08/279,951 patent/US5679480A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE69409446D1 (en) | 1998-05-14 |
| CA2128745A1 (en) | 1995-01-27 |
| EP0637090A1 (en) | 1995-02-01 |
| DE69409446T2 (en) | 1998-08-06 |
| US5679480A (en) | 1997-10-21 |
| EP0637090B1 (en) | 1998-04-08 |
| JPH0737577A (en) | 1995-02-07 |
| DE637090T1 (en) | 1995-10-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20010725 |