JP2016050120A - Low alkali nickel lithium metal composite oxide fine particles and method for producing the same - Google Patents
Low alkali nickel lithium metal composite oxide fine particles and method for producing the same Download PDFInfo
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 165
- RSNHXDVSISOZOB-UHFFFAOYSA-N lithium nickel Chemical compound [Li].[Ni] RSNHXDVSISOZOB-UHFFFAOYSA-N 0.000 title claims abstract description 141
- 239000002905 metal composite material Substances 0.000 title claims abstract description 137
- 238000004519 manufacturing process Methods 0.000 title claims description 59
- 239000003513 alkali Substances 0.000 title abstract description 10
- 239000010419 fine particle Substances 0.000 title abstract 4
- 239000007774 positive electrode material Substances 0.000 claims abstract description 67
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 64
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 64
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000007789 gas Substances 0.000 claims abstract description 47
- 239000002994 raw material Substances 0.000 claims abstract description 33
- 239000006228 supernatant Substances 0.000 claims abstract description 26
- 238000004458 analytical method Methods 0.000 claims abstract description 16
- 239000000203 mixture Substances 0.000 claims abstract description 16
- 239000006185 dispersion Substances 0.000 claims abstract description 15
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 claims abstract 3
- 238000010304 firing Methods 0.000 claims description 117
- 239000000843 powder Substances 0.000 claims description 116
- 238000000034 method Methods 0.000 claims description 51
- 229910052751 metal Inorganic materials 0.000 claims description 21
- 229910052782 aluminium Inorganic materials 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 14
- 238000005406 washing Methods 0.000 claims description 11
- -1 nickel lithium metal complex Chemical class 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- 229910052796 boron Inorganic materials 0.000 claims description 8
- 229910052715 tantalum Inorganic materials 0.000 claims description 8
- 229910052721 tungsten Inorganic materials 0.000 claims description 8
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 238000004993 emission spectroscopy Methods 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 238000001556 precipitation Methods 0.000 claims description 7
- 238000004090 dissolution Methods 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 238000001354 calcination Methods 0.000 abstract description 5
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 28
- 229910001882 dioxygen Inorganic materials 0.000 description 28
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 24
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- 239000002131 composite material Substances 0.000 description 16
- 238000010248 power generation Methods 0.000 description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 14
- 229910052759 nickel Inorganic materials 0.000 description 14
- 239000001301 oxygen Substances 0.000 description 14
- 229910052760 oxygen Inorganic materials 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- 238000010438 heat treatment Methods 0.000 description 12
- 150000002500 ions Chemical class 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 10
- 239000002243 precursor Substances 0.000 description 10
- 239000002033 PVDF binder Substances 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 8
- 239000011230 binding agent Substances 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 8
- 238000001514 detection method Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- 238000003860 storage Methods 0.000 description 8
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 6
- 239000011149 active material Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 6
- 229940044175 cobalt sulfate Drugs 0.000 description 6
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 239000011267 electrode slurry Substances 0.000 description 6
- 238000001879 gelation Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 6
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 6
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 4
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 4
- QXZUUHYBWMWJHK-UHFFFAOYSA-N [Co].[Ni] Chemical compound [Co].[Ni] QXZUUHYBWMWJHK-UHFFFAOYSA-N 0.000 description 4
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 4
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 4
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 description 4
- 239000000706 filtrate Substances 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000001291 vacuum drying Methods 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-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
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000002482 conductive additive Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 238000000265 homogenisation Methods 0.000 description 2
- 238000007602 hot air drying Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000007603 infrared drying Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 2
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910000000 metal hydroxide Inorganic materials 0.000 description 2
- 150000004692 metal hydroxides Chemical class 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 238000001139 pH measurement Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000007581 slurry coating method Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
Classifications
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- 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
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- Inorganic Compounds Of Heavy Metals (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は低アルカリニッケルリチウム金属複合酸化物粉体、これを含むリチウムイオン電池正極物質、該活物質を用いたリチウムイオン電池正極、この正極を有するリチウムイオン電池、及び上記低アルカリニッケルリチウム金属複合酸化物の製造方法に関する。 The present invention relates to a low alkali nickel lithium metal composite oxide powder, a lithium ion battery positive electrode material including the same, a lithium ion battery positive electrode using the active material, a lithium ion battery having the positive electrode, and the low alkali nickel lithium metal composite The present invention relates to an oxide manufacturing method.
スマートフォン、タブレット型パソコン等の小型電子機器の普及により、ユーザーが屋外で長時間これら小型電子機器を携帯し利用することは、もはや一般的になっている。そのため、これら小型電子機器の電源である電池には長時間の使用に耐える高容量の電池であることが求められており、そのような要求を満たすリチウムイオン二次電池が盛んに研究開発されている。同時に、スマートフォン、タブレット型パソコン等の小型電子機器の更なる高機能化、高性能化が図られており、そのような高機能・高性能小型電子機器では消費電力の増大が避けられない。したがって、電池の高容量化への要求がますます高まっている。 With the spread of small electronic devices such as smartphones and tablet computers, it is no longer common for users to carry and use these small electronic devices outdoors for a long time. For this reason, batteries that are the power sources of these small electronic devices are required to have a high capacity that can withstand long-term use, and lithium-ion secondary batteries that satisfy such requirements have been actively researched and developed. Yes. At the same time, small electronic devices such as smartphones and tablet computers are being further enhanced in function and performance, and such high-performance and high-performance small electronic devices cannot avoid increasing power consumption. Therefore, there is an increasing demand for higher battery capacity.
また、近年は、エネルギー受給に対する危機意識や環境志向の高まりよって、風力発電、メガソーラー発電、家庭用太陽光発電と言った、従来型の集中型発電所とは異なる独立分散型発電設備の設置が増えている。しかしながら、風力発電、太陽光発電等の自然エネルギーを利用した発電設備が従来の発電施設に比べて電気供給の安定性に劣るという問題は、未だ解決されていない。２０１１年３月１１日に発生した東日本大震災、その後に引き起こされた原子力発電所停止にかかる給電状況の悪化以来、地震等の災害発生時に事業所や家庭単位の電力確保が重要であることが広く認識されるようになってきた。このため、消費地点単位で電源確保を確保する定置用蓄電池に注目が集まっている。しかしながら、現在の技術によれば、このような定置用蓄電池によって電気容量を確保するためには非常に大きな蓄電設備が必要とされる。このため、日本の住宅環境においてはそのような蓄電設備は、現時点では実用性を欠く。 Also, in recent years, due to the growing awareness of energy crisis and environmental awareness, the installation of independent and decentralized power generation facilities, such as wind power generation, mega solar power generation, and home solar power generation, which are different from conventional centralized power plants. Is increasing. However, the problem that power generation facilities using natural energy such as wind power generation and solar power generation are inferior to the stability of electricity supply as compared with conventional power generation facilities has not yet been solved. Since the Great East Japan Earthquake that occurred on March 11, 2011, and the deterioration of the power supply situation caused by the subsequent stoppage of nuclear power plants, it has been widely important to secure power for business units and households when disasters such as earthquakes occur It has come to be recognized. For this reason, attention has been focused on stationary storage batteries that ensure the supply of power on a consumption point basis. However, according to the current technology, a very large power storage facility is required to secure electric capacity with such a stationary storage battery. For this reason, in the Japanese residential environment, such power storage equipment lacks utility at present.
更に自動車産業においては、エネルギー効率のよい電気自動車、ハイブリッド自動車に注目が集まり、これらの自動車の開発が盛んに行われている。しかしながら、電池容量の不足による航続距離の不十分さ、加えて市中における充電設備の絶対的不足という問題は解決されていない。そのため、現時点では、電気エネルギーだけで動く電気自動車は、ハイブリッド自動車ほどには普及していない。 Further, in the automobile industry, attention is focused on energy efficient electric vehicles and hybrid vehicles, and development of these vehicles is actively performed. However, the problem of insufficient cruising distance due to insufficient battery capacity and the absolute shortage of charging facilities in the city has not been solved. Therefore, at present, electric vehicles that run only on electric energy are not as popular as hybrid vehicles.
上述のような、電子機器、電力確保、自動車などの産業を支える共通の製品の一つがリチウムイオン電池である。上述のような問題点に共通する原因が、リチウムイオン電池の体積当たりの容量が足りないことにある。リチウムイオン電池の体積当たりの容量が足りないという問題を引き起こす大きな要因は、リチウムイオン二次電池に用いられる正極活物質の単位体積当たりの放電容量が小さいことである。 One of the common products that support industries such as electronic devices, power securing, and automobiles as described above is a lithium ion battery. A common cause of the above problems is that the capacity per volume of the lithium ion battery is insufficient. A major factor causing the problem that the capacity per volume of the lithium ion battery is insufficient is that the discharge capacity per unit volume of the positive electrode active material used in the lithium ion secondary battery is small.
リチウムイオン電池の正極活物質としては、コバルト酸リチウム（ＬＣＯ）に代表されるコバルト系正極活物質が用いられてきた。コバルト酸リチウムを用いて電極を作成すると、電極密度は１立方センチメートル当たり３．９ｇを超える大密度を達成できる。しかしその一方、コバルト酸リチウム自身の放電容量は実質１５０ｍＡｈ／ｇ程度と低い。 As a positive electrode active material of a lithium ion battery, a cobalt-based positive electrode active material typified by lithium cobaltate (LCO) has been used. When an electrode is made using lithium cobaltate, an electrode density of greater than 3.9 g per cubic centimeter can be achieved. However, on the other hand, the discharge capacity of lithium cobalt oxide itself is as low as about 150 mAh / g.
リチウムイオン電池の正極活物質としては、ＬＮＣＯ（Ｌｉ、Ｎｉ、Ｃｏの複合酸化物），特にＬＮＣＡＯ（Ｌｉ、Ｎｉ、Ｃｏ、Ａｌの複合酸化物）に代表されるニッケル系正極活物質も検討されている。ＬＮＣＡＯの単位重量当たりの放電容量はコバルト系正極活物質よりも大きく、１９０ｍＡｈ／ｇを超える。しかしその一方、このような正極活物質を用いて電極を作成する際の問題が指摘されている。すなわち、活物質とバインダーとからなるスラリーがゲル化し、このゲル化がスラリーの塗布性を悪化させるという問題がある。このゲル化は、強いアルカリ性を示す活物質がバインダーとして用いられるＰＶＤＦ（ポリビニリデンフルオライド系重合体）からフッ素を脱離させ、ＰＶＤＦ樹脂鎖の架橋が起こることに起因すると考えられている。そこで、ＬＮＣＡＯ（Ｌｉ、Ｎｉ、Ｃｏ、Ａｌの複合酸化物）に代表されるニッケル系正極活物質に含まれるアルカリ性物質を低減することが求められている。
リチウムイオン電池の正極活物質のｐＨを低減する手段としては、例えば、特許文献１には、正極活物質に特定の化合物を接触させて、正極活物質中に残存するアルカリ性化合物をアルカリ性の低い化合物に変換する方法が記載されている。特許文献２には、焼成後のニッケル酸リチウム粉末を高純度二酸化炭素ガスで処理する方法が記載されている。しかし、このような手段は、従来の製造工程に加えた新たな工程を必要とするために、コスト面で問題がある。
As a positive electrode active material of a lithium ion battery, a nickel-based positive electrode active material represented by LNCO (Li, Ni, Co composite oxide), particularly LNCAO (Li, Ni, Co, Al composite oxide) has been studied. ing. The discharge capacity per unit weight of LNCAO is larger than that of the cobalt-based positive electrode active material, and exceeds 190 mAh / g. On the other hand, however, problems in making an electrode using such a positive electrode active material have been pointed out. That is, there is a problem that the slurry composed of the active material and the binder is gelled, and this gelation deteriorates the applicability of the slurry. This gelation is considered to be caused by the fact that an active material exhibiting strong alkalinity desorbs fluorine from PVDF (polyvinylidene fluoride-based polymer) used as a binder and crosslinks the PVDF resin chain. Therefore, it is required to reduce an alkaline substance contained in a nickel-based positive electrode active material typified by LNCAO (Li, Ni, Co, Al composite oxide).
As a means for reducing the pH of the positive electrode active material of the lithium ion battery, for example, in Patent Document 1, a specific compound is brought into contact with the positive electrode active material, and the alkaline compound remaining in the positive electrode active material is reduced to a compound having low alkalinity. The method of converting to is described. Patent Document 2 describes a method of treating a fired lithium nickelate powder with high-purity carbon dioxide gas. However, since such a method requires a new process in addition to the conventional manufacturing process, there is a problem in cost.
本発明は、ＬＮＣＡＯに代表される正極活物質に残留するアルカリ性物質を低減し、電極製造や電池性能に有利な正極活物質を提供することを課題とする。また本発明では、より低コストで簡単な手段で低アルカリ性ＬＮＣＡＯ系正極活物質を得ることを目的とする。 An object of the present invention is to reduce the alkaline material remaining in a positive electrode active material typified by LNCAO and to provide a positive electrode active material advantageous for electrode production and battery performance. Another object of the present invention is to obtain a low alkaline LNCAO-based positive electrode active material by simple means at a lower cost.
本発明の発明者は、ＬＮＣＡＯに代表される正極活物質の製造において、特定の条件で焼成を行うこと、すなわち、露点０〜７０℃の湿潤雰囲気で焼成を行うことにより、ｐＨが低減された正極活物質を得た。しかも、本発明では、正極活物質から溶出するＡｌ量も低減することができ、正極活物質の安定性を向上することにも成功した。 The inventor of the present invention reduced the pH by producing a positive electrode active material typified by LNCAO by firing under specific conditions, that is, firing in a humid atmosphere with a dew point of 0 to 70 ° C. A positive electrode active material was obtained. Moreover, in the present invention, the amount of Al eluted from the positive electrode active material can also be reduced, and the stability of the positive electrode active material has been successfully improved.
すなわち本発明は以下のものである。 That is, the present invention is as follows.
（発明１）以下の一般式 （１）で表されるニッケルリチウム金属複合酸化物からなり、 (Invention 1) A nickel-lithium metal composite oxide represented by the following general formula (1):
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下であることを特徴とする、低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.) Hydrogen in the supernatant when 2 g of this was dispersed in 100 g of water The ion concentration is 11.7 or less in pH, and the Al concentration measured by ICP emission spectrometry of the supernatant when 2 g of the ion is dispersed in 100 g of water is 2.5 ppm or less. Alkaline nickel-lithium metal composite oxide powder.
（発明２）さらに、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＬｉ濃度が４５ｐｐｍ以下であることを特徴とする、発明１に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 2) The low alkaline nickel lithium according to Invention 1, wherein the Li concentration measured by ICP emission analysis of the supernatant when 2 g of the dispersion is dispersed in 100 g of water is 45 ppm or less. Metal composite oxide powder.
（発明３）一般式（１）におけるＭがＣｏであることを特徴とする、発明１または２に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 3) The low alkaline nickel lithium metal composite oxide powder according to Invention 1 or 2, wherein M in the general formula (1) is Co.
（発明４）一般式（１）におけるＮがＡｌであることを特徴とする、発明１〜３のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 4) The low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 1 to 3, wherein N in the general formula (1) is Al.
（発明５）一般式（１）における一般式（１）におけるＭがＣｏであり、かつ、ＮがＡｌであることを特徴とする、発明１〜４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 5) The low alkaline nickel lithium metal according to any one of Inventions 1 to 4, wherein M in the general formula (1) in the general formula (1) is Co and N is Al. Composite oxide powder.
（発明６）発明１〜５のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体を含むことを特徴とする、リチウムイオン電池用正極活物質。 (Invention 6) A positive electrode active material for a lithium ion battery, comprising the low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 1 to 5.
（発明７）発明６に記載のリチウムイオン電池用正極活物質を用いることを特徴とする、リチウムイオン電池用正極。 (Invention 7) A positive electrode for a lithium ion battery, characterized in that the positive electrode active material for a lithium ion battery according to Invention 6 is used.
（発明８）発明７に記載のリチウムイオン電池用正極を備えることを特徴とする、リチリウムイオン電池。 (Invention 8) A lithium ion battery comprising the positive electrode for a lithium ion battery according to Invention 7.
（発明９）以下の一般式 （１）で表されるニッケルリチウム金属複合酸化物からなり、 (Invention 9) A nickel-lithium metal composite oxide represented by the following general formula (1):
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下である低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法であって、原料混合物の焼成工程の少なくとも一部を、露点が０〜７０℃である湿潤雰囲気ガス中で行うことを特徴とする、低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.) Hydrogen in the supernatant when 2 g of this was dispersed in 100 g of water Low alkaline nickel-lithium metal composite oxide having an ion concentration of 11.7 or less in pH and an Al concentration of 2.5 ppm or less measured by ICP emission analysis of the supernatant when 2 g of the solution is dispersed in 100 g of water A low-alkali nickel-lithium metal composite oxide powder, characterized in that at least a part of the firing step of the raw material mixture is performed in a humid atmosphere gas having a dew point of 0 to 70 ° C. Body manufacturing method.
（発明１０）さらに、低アルカリ性ニッケルリチウム金属複合酸化物粉体が、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＬｉ濃度が４５ｐｐｍ以下であることを特徴とする、発明９に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 10) Further, in the low alkaline nickel lithium metal composite oxide powder, the Li concentration measured by ICP emission spectrometry of the supernatant when 2 g of the powder is dispersed in 100 g of water is 45 ppm or less. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder of invention 9.
（発明１１）一般式（１）におけるＭがＣｏであることを特徴とする、発明９または１０に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 11) The method for producing a low alkaline nickel lithium metal composite oxide powder according to Invention 9 or 10, wherein M in the general formula (1) is Co.
（発明１２）一般式（１）におけるＮがＡｌであることを特徴とする、発明９〜１１のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 12) The method for producing a low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 9 to 11, wherein N in the general formula (1) is Al.
（発明１３）一般式（１）における一般式（１）におけるＭがＣｏであり、かつ、ＮがＡｌであることを特徴とする、発明９〜１２のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 13) The low alkaline nickel lithium metal according to any one of Inventions 9 to 12, wherein M in the general formula (1) in the general formula (1) is Co and N is Al. A method for producing a composite oxide powder.
（発明１４）原料混合物の焼成工程の少なくとも一部を、露点が３０〜５０℃である湿潤雰囲気ガス中で行うことを特徴とする、発明９〜１３のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 14) The low alkaline nickel lithium metal according to any one of Inventions 9 to 13, wherein at least a part of the firing step of the raw material mixture is performed in a humid atmosphere gas having a dew point of 30 to 50 ° C. A method for producing a composite oxide powder.
（発明１５）焼成工程の全部を露点が０〜７０℃である湿潤雰囲気ガス中で行うことを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 15) A low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 9 to 14, wherein the entire firing step is performed in a humid atmosphere gas having a dew point of 0 to 70 ° C. Production method.
（発明１６）焼成工程において、乾燥雰囲気で昇温を開始し、温度が最高温度に達する時点以前に焼成雰囲気を露点が０〜７０℃である湿潤雰囲気ガスに切り替えることを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 16) In the firing step, the temperature rise is started in a dry atmosphere, and the firing atmosphere is switched to a wet atmosphere gas having a dew point of 0 to 70 ° C. before the temperature reaches the maximum temperature. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder in any one of -14.
（発明１７）焼成工程において、露点が０〜７０℃である湿潤雰囲気ガス中で昇温を開始し、焼成後の冷却を開始する時点以前に焼成雰囲気を乾燥雰囲気ガスに切り替えることを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 17) In the firing step, the temperature rise is started in a humid atmosphere gas having a dew point of 0 to 70 ° C., and the firing atmosphere is switched to the dry atmosphere gas before starting the cooling after firing. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder in any one of invention 9-14.
（発明１８）原料混合物の焼成工程を、原料の溶解工程、沈殿工程、ろ過・洗浄工程、乾燥工程を経た粉体混合工程の後に行うことを特徴とする、発明９〜１７のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 18) The invention according to any one of Inventions 9 to 17, wherein the firing step of the raw material mixture is performed after the raw material dissolution step, the precipitation step, the filtration / washing step, and the drying step. Of producing low alkaline nickel lithium metal composite oxide powder.
（発明１９）焼成工程の後に、さらに、低アルカリ性ニッケルリチウム金属複合酸化物粉体の解砕工程を設けることを特徴とする、発明９〜１８のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 19) The low alkaline nickel lithium metal composite oxide according to any one of inventions 9 to 18, further comprising a crushing step of the low alkaline nickel lithium metal composite oxide powder after the firing step. A method for manufacturing powder.
本発明のニッケルリチウム金属複合酸化物粉体は、低アルカリ性であり、溶出性Al含有量が低減されている。 The nickel lithium metal composite oxide powder of the present invention has low alkalinity and has a reduced eluting Al content.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を構成するニッケルリチウム金属複合酸化物は、以下の一般式（１）で表される。 The nickel lithium metal composite oxide constituting the low alkaline nickel lithium metal composite oxide powder of the present invention is represented by the following general formula (1).
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を構成するニッケルリチウム金属複合酸化物は、好ましくは、上記一般式（１）においてMがCo、NがAlである、以下の一般式（２）で表される。
(In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.)
The nickel lithium metal composite oxide constituting the low alkaline nickel lithium metal composite oxide powder of the present invention preferably has the following general formula (2) wherein M is Co and N is Al in the general formula (1). ).
（ただし式（２）中、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
（製造方法）
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体は、以下の方法により製造することができる。
(In the formula (2), 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.)
(Production method)
The low alkaline nickel lithium metal composite oxide powder of the present invention can be produced by the following method.
（１．原料の溶解）原料としては、一般式（１）を構成する金属の、硫酸塩、硝酸塩などの可溶性金属塩を用いることができる。硝酸塩を用いた場合、硝酸性窒素を含む廃液処理にコストがかかるため、硝酸塩の使用は工業的には好ましくない。通常は一般式（１）を構成する金属の硫酸塩が用いられる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、まず、原料である硫酸ニッケル、硫酸コバルトのそれぞれを水に溶解する。 (1. Dissolution of raw materials) As raw materials, soluble metal salts such as sulfates and nitrates of metals constituting the general formula (1) can be used. When nitrate is used, it is costly to treat waste liquid containing nitrate nitrogen, so use of nitrate is not industrially preferable. Usually, a metal sulfate constituting the general formula (1) is used. In the method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention, first, each of nickel sulfate and cobalt sulfate as raw materials is dissolved in water.
（２．沈殿）硫酸ニッケル水溶液、硫酸コバルト水溶液、沈殿剤としての水酸化ナトリウムとアンモニア水を沈殿槽内で混合する。水酸化ニッケルと水酸化コバルトの共沈殿物が生成する。 (2. Precipitation) A nickel sulfate aqueous solution, a cobalt sulfate aqueous solution, sodium hydroxide as a precipitating agent and aqueous ammonia are mixed in a precipitation tank. A coprecipitate of nickel hydroxide and cobalt hydroxide is formed.
（３．濾過・洗浄）沈殿物を濾過し、水分を除去して水酸化物ケーキを分離する。水酸化物ケーキを水酸化ナトリウム水溶液で洗浄し、硫酸イオンを除去する。さらに水酸化物ケーキを純水で洗浄して水酸化ナトリウムを除去する。こうして水酸化ニッケルと水酸化コバルトからなる前駆体ケーキが得られる。 (3. Filtration / Washing) The precipitate is filtered to remove moisture and separate the hydroxide cake. The hydroxide cake is washed with an aqueous sodium hydroxide solution to remove sulfate ions. Further, the hydroxide cake is washed with pure water to remove sodium hydroxide. Thus, a precursor cake composed of nickel hydroxide and cobalt hydroxide is obtained.
（４．乾燥）前駆体ケーキを乾燥する。乾燥方法は、大気圧下での熱風乾燥、赤外線乾燥、真空乾燥などのいずれでもよい。真空乾燥を行うことにより短時間で乾燥することができる。前駆体中の水分が１重量％程度になるまで乾燥する。 (4. Drying) The precursor cake is dried. The drying method may be any of hot air drying under atmospheric pressure, infrared drying, vacuum drying, and the like. It can dry in a short time by performing vacuum drying. Dry until the water content in the precursor is about 1% by weight.
（５．粉体混合）乾燥後の前駆体粉末に、水酸化アルミニウムと水酸化リチウム粉末を加え、剪断力をかけて混合する。 (5. Powder mixing) Aluminum hydroxide and lithium hydroxide powder are added to the dried precursor powder and mixed by applying a shearing force.
（６．焼成）混合物を酸素存在下で焼成する。焼成により、以下の反応が起こる。 (6. Firing) The mixture is fired in the presence of oxygen. The following reaction occurs by firing.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法は、焼成工程の少なくとも一部を、湿潤雰囲気中で行うことを特徴とする。すなわち、本発明では、温度を上げて焼成工程を開始する時点から、最高温度に一定時間保持した後に冷却して焼成工程を終了する時点までの期間のうち、少なくとも１部分を、湿潤雰囲気中で行う。本発明の製造方法で採用される湿潤雰囲気は、露点が０〜７０℃、好ましくは３０〜５０℃の範囲にある、酸素含有気体である。酸素含有気体としては、酸素ガス、空気などが使用される。焼成工程において、最高温度は６５０〜８５０℃の範囲とし、この最高温度を２〜３０時間保持して焼成する。焼成の後、冷却する。こうして焼成工程が完了する。 The method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention is characterized in that at least a part of the firing step is performed in a humid atmosphere. That is, in the present invention, at least one part of the period from the time when the firing process is started by raising the temperature to the time when the firing process is finished after being held at the maximum temperature for a certain period of time is kept in a humid atmosphere. Do. The moist atmosphere employed in the production method of the present invention is an oxygen-containing gas having a dew point of 0 to 70 ° C, preferably 30 to 50 ° C. As the oxygen-containing gas, oxygen gas, air, or the like is used. In the firing step, the maximum temperature is in the range of 650 to 850 ° C., and the maximum temperature is maintained for 2 to 30 hours for firing. After firing, cool. Thus, the firing process is completed.
焼成工程のいずれの部分を湿潤雰囲気中で行うかは、特に制限は無い。焼成工程全部を湿潤雰囲気中で行ってもよい。乾燥雰囲気で焼成工程を開始し、後に湿潤雰囲気に切り替えてもよい。また、湿潤雰囲気で焼成工程を開始し、後に乾燥雰囲気に切り替えてもよい。 There is no particular limitation on which part of the firing step is performed in a humid atmosphere. The entire firing step may be performed in a humid atmosphere. The firing process may be started in a dry atmosphere and later switched to a wet atmosphere. Alternatively, the firing process may be started in a wet atmosphere and then switched to a dry atmosphere.
乾燥雰囲気で焼成工程を開始し、後に湿潤雰囲気に切り替える場合は、一般には、湿潤雰囲気への切り替えを最高温度に達する時点以前に行う。すなわち、昇温中か、あるいは最高温度に達した時点で行う。好ましい切り替え時は昇温中である。 When starting the firing process in a dry atmosphere and switching to a wet atmosphere later, the switch to the wet atmosphere is generally performed before the time when the maximum temperature is reached. That is, it is performed during the temperature rise or when the maximum temperature is reached. During preferred switching, the temperature is rising.
湿潤雰囲気で焼成工程を開始し、後に乾燥雰囲気に切り替える場合は、一般には、乾燥雰囲気への切り替えは、冷却を開始する時点以前に行う。すなわち、昇温中、最高温度が保持されている間、あるいは、最高温度に保持して焼成を終了した後に冷却を開始する時点で行う。 When the firing process is started in a wet atmosphere and then switched to a dry atmosphere, generally, the switch to the dry atmosphere is performed before the start of cooling. That is, it is performed while the maximum temperature is maintained during the temperature increase, or when the cooling is started after the baking is completed while maintaining the maximum temperature.
焼成雰囲気への水分供給方法は、所望の露点を達成できる方法であれば、いずれも採用することができる。例えば、酸素含有気体を洗気瓶等を用いて液体の水にバブリングすることによって雰囲気に使用する気体に水分を供給する方法、酸素含有気体に噴霧器等を用いて霧状の水を供給し、所望する露点の雰囲気の気体を供給する方法が利用できる。工業生産現場においては、焼成原料である水酸化ニッケル、水酸化リチウム及び水酸化金属の混合物から焼成中に発生する水分の利用、上述の水分供給方法と、水分を含まない雰囲気気体供給を組み合わせて、焼成雰囲気の露点を所望の範囲に調整する。 Any method can be employed as a method for supplying moisture to the firing atmosphere as long as a desired dew point can be achieved. For example, a method of supplying moisture to the gas used for the atmosphere by bubbling oxygen-containing gas to liquid water using a washing bottle, etc., supplying atomized water to the oxygen-containing gas using a sprayer or the like, A method of supplying a gas having a desired dew point atmosphere can be used. In industrial production sites, the use of moisture generated during firing from a mixture of nickel hydroxide, lithium hydroxide and metal hydroxide as firing raw materials, the above-described moisture supply method, and the combination of atmospheric gas supply without moisture The dew point of the firing atmosphere is adjusted to a desired range.
このような特定の湿潤雰囲条件で焼成することにより、本発明では焼成後のニッケルリチウム金属複合酸化物に含まれる強アルカリ物質を低減することができる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体２ｇを１００ｇの水に分散させた場合、分散液上澄のｐＨは１１．７以下に低減される。また、ＩＣＰ発光分析法による分散液上澄のＬｉ含有量は、４５ｐｐｍ以下である。 By firing under such specific wet atmosphere conditions, in the present invention, the strong alkaline substance contained in the nickel-lithium metal composite oxide after firing can be reduced. When 2 g of the low alkaline nickel lithium metal composite oxide powder of the present invention is dispersed in 100 g of water, the pH of the dispersion supernatant is reduced to 11.7 or lower. Moreover, Li content of the dispersion supernatant liquid by ICP emission analysis is 45 ppm or less.
湿潤雰囲気中での焼成によって低アルカリ性ニッケルリチウム金属複合酸化物粉体が得られる理由は現時点では完全には解明されていない。焼成雰囲気中の水分によって、ニッケルリチウム金属複合酸化物の表面に存在する酸化リチウムの形態で存在するリチウムイオンが、水酸化リチウムの形態で存在する移動性の高いリチウムイオンに変化すること、この変化によってリチウムイオンがニッケルリチウム金属複合酸化物の表面からその結晶内に移動すること、リチウムイオンの結晶内への均質化が水へ溶出するリチウムイオン濃度の減少をもたらすこと、が推測されている。 The reason why low alkaline nickel lithium metal composite oxide powder can be obtained by firing in a humid atmosphere has not been fully elucidated at this time. Due to moisture in the firing atmosphere, the lithium ion present in the form of lithium oxide present on the surface of the nickel-lithium metal composite oxide changes to a highly mobile lithium ion present in the form of lithium hydroxide. It is speculated that the lithium ions move from the surface of the nickel lithium metal composite oxide into the crystal due to the above, and that the homogenization of the lithium ions into the crystal results in a decrease in the concentration of lithium ions eluted into water.
このように低アルカリ性を示す本発明のニッケルリチウム金属複合酸化物は、リチウムイオン電池正極剤スラリーにバインダーとして含まれるＰＶＤＦとの反応性が低い。このため、本発明のニッケルリチウム金属複合酸化物を正極活物質として使用した場合、正極製造時の正極剤スラリーのゲル化が起こりにくく、スラリーの塗工工程に問題が生じない。 Thus, the nickel lithium metal composite oxide of the present invention showing low alkalinity has low reactivity with PVDF contained as a binder in the lithium ion battery positive electrode slurry. For this reason, when the nickel lithium metal composite oxide of the present invention is used as the positive electrode active material, gelation of the positive electrode agent slurry during the production of the positive electrode hardly occurs, and no problem occurs in the slurry coating process.
その一方で、このような特定の湿潤雰囲気中で焼成することにより、本発明では焼成後のニッケルリチウム金属複合酸化物に含まれる溶出性Ａｌ化合物の量も低減することができる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体２ｇを１００ｇの水に分散させた場合、ＩＣＰ発光分析法による分散液上澄のＡｌ含有量は、検出限界２．５ｐｐｍを下回る。 On the other hand, by firing in such a specific moist atmosphere, in the present invention, the amount of the eluting Al compound contained in the nickel-lithium metal composite oxide after firing can also be reduced. When 2 g of the low alkaline nickel lithium metal composite oxide powder of the present invention is dispersed in 100 g of water, the Al content of the dispersion supernatant by ICP emission analysis is below the detection limit of 2.5 ppm.
このように溶出性Ａｌ含有量の低い本発明のニッケルリチウム金属複合酸化物をリチウムイオン電池の正極活物質として用いた場合、電池のサイクル特性及び熱安定性が向上すると考えられる。これはAlイオンがニッケルリチウム金属複合酸化物の層状構造中に存在するＮｉイオンと同型置換することにより、ニッケル系正極材の欠点の一つである結晶構造の不安定性が抑制され、層状構造の安定化に寄与すると考えられる為である。 Thus, when the nickel lithium metal composite oxide of the present invention having a low eluting Al content is used as a positive electrode active material of a lithium ion battery, it is considered that the cycle characteristics and thermal stability of the battery are improved. This is because Al ions are replaced by the same type of Ni ions present in the layered structure of nickel-lithium metal composite oxide, so that the instability of the crystal structure, which is one of the disadvantages of nickel-based positive electrode materials, is suppressed. This is because it is thought to contribute to stabilization.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、焼成工程の少なくとも一部分を上述の湿潤雰囲気下で行うことによって、焼成後のニッケルリチウム金属複合酸化物のｐＨが低減し、溶出性Ａｌ含有量も低減する。 In the method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention, the pH of the nickel lithium metal composite oxide after firing is reduced and eluted by performing at least a part of the firing step in the above-mentioned wet atmosphere. The Al content is also reduced.
（７．解砕）本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、焼成工程の後に、必要に応じて、さらに解砕工程を設けることができる。解砕工程では、ジェットミルなどの解砕機を用いて、焼成後の低アルカリ性ニッケルリチウム金属複合酸化物粉体の凝集した粒子を解砕する。適度に細粒化されたニッケルリチウム金属複合酸化物を用いると、均一で塗布性に優れる正極剤スラリーが得られる。このような正極剤スラリーにより、正極電極の生産効率を向上させることができる。しかも、正極活物質のイオン放出性も安定化され、電池性能も向上する。 (7. Crushing) In the method for producing the low alkaline nickel lithium metal composite oxide powder of the present invention, a crushing step can be further provided as necessary after the firing step. In the pulverization step, the aggregated particles of the low alkaline nickel lithium metal composite oxide powder after calcination are pulverized using a pulverizer such as a jet mill. When a nickel-lithium metal composite oxide finely grained is used, a uniform positive electrode slurry having excellent coating properties can be obtained. The positive electrode slurry can improve the production efficiency of the positive electrode. In addition, the ion release property of the positive electrode active material is stabilized, and the battery performance is improved.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体は、リチウムイオン電池の正極活物質として利用できる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体のみでリチウムイオン電池の正極活物質を構成してもよいし、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体に、その長所が発現する程度の量で他のニッケルリチウム金属複合酸化物を混合してもよい。例えば、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体５０重量部と、本発明以外のリチウムイオン電池二次電池用正極活物質５０重量部とを混合したものを正極活物質として用いることができる。リチウムイオン電池の正極を製造する場合には、上述の本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を含む正極活物質、導電助剤、バインダー、分散用有機溶媒を加えて正極用合剤スラリーを調製し、電極に塗布する。 The low alkaline nickel lithium metal composite oxide powder of the present invention can be used as a positive electrode active material of a lithium ion battery. The positive electrode active material of the lithium ion battery may be composed only of the low alkaline nickel lithium metal composite oxide powder of the present invention, and the advantages are manifested in the low alkaline nickel lithium metal composite oxide powder of the present invention. Other nickel lithium metal composite oxides may be mixed in a certain amount. For example, a mixture of 50 parts by weight of the low alkaline nickel lithium metal composite oxide powder of the present invention and 50 parts by weight of a positive electrode active material for a lithium ion battery secondary battery other than the present invention is used as the positive electrode active material. it can. When producing a positive electrode of a lithium ion battery, a positive electrode active material containing the above-mentioned low alkaline nickel lithium metal composite oxide powder of the present invention, a conductive additive, a binder, and an organic solvent for dispersion are added to mix the positive electrode. A slurry is prepared and applied to the electrode.
以下の方法で、低アルカリ性ニッケルリチウム金属複合酸化物前駆体を製造し、露点を調節した湿潤雰囲気中で焼成して、低アルカリ性ニッケルリチウム金属複合酸化物粉体を製造した。 A low alkaline nickel lithium metal composite oxide precursor was produced by the following method and fired in a humid atmosphere with a controlled dew point to produce a low alkaline nickel lithium metal composite oxide powder.
（焼成原料の調製）硫酸ニッケル及び硫酸コバルトを溶解させた水溶液に水酸化ナトリウム水溶液を加え、生じた沈殿を濾過、洗浄、乾燥することによりニッケル−コバルト複合水酸化物を得た。このニッケル−コバルト複合水酸化物７２．９ｇに水酸化リチウム２０．３ｇと水酸化アルミニウム４．８ｇを粉体で混合し焼成原料とした。この焼成原料をこの焼成原料３０ｇをアルミナボートに取り、内径５０ｍｍの石英管を設置した電気管状炉内に設置して、後述の実施例、比較例の操作に用いた。 (Preparation of calcination raw material) A sodium hydroxide aqueous solution was added to an aqueous solution in which nickel sulfate and cobalt sulfate were dissolved, and the resulting precipitate was filtered, washed and dried to obtain a nickel-cobalt composite hydroxide. Lithium hydroxide (20.3 g) and aluminum hydroxide (4.8 g) were mixed in powder form with 72.9 g of this nickel-cobalt composite hydroxide to obtain a calcined raw material. This calcined raw material was placed in an electric tubular furnace in which 30 g of this calcined raw material was placed in an alumina boat and a quartz tube having an inner diameter of 50 mm was installed, and used for the operations of Examples and Comparative Examples described later.
（焼成時雰囲気の露点調製）２０℃に保温した水を入れた洗気瓶を２本用意し各々を直列に接続する。この２本の洗気瓶を通した気体を、露点２０℃の気体と定義する。露点４０℃の気体は上記の水に４０℃の水を用い、露点６０℃の気体は上記の水に６０℃の水を用いた。気体として酸素を用いた。 (Preparation of dew point of atmosphere during firing) Prepare two washing bottles containing water kept at 20 ° C. and connect them in series. The gas that has passed through the two washing bottles is defined as a gas having a dew point of 20 ° C. A gas having a dew point of 40 ° C. used 40 ° C. water as the water, and a gas having a dew point of 60 ° C. used 60 ° C. water as the water. Oxygen was used as the gas.
（焼成）上述焼成原料を設置した電気管状炉内に、露点を制御した酸素ガスを導入し、最高温度７８０℃で焼成したものを正極活物質とした。 (Baking) A positive electrode active material was obtained by introducing oxygen gas with a controlled dew point into an electric tubular furnace in which the above-mentioned baking raw material was installed and baking at a maximum temperature of 780 ° C.
焼成後のニッケルリチウム金属複合酸化物を以下の方法で分析、評価した。 The nickel lithium metal composite oxide after firing was analyzed and evaluated by the following method.
（ｐH測定）焼成後のニッケルリチウム金属複合酸化物２ｇを２５℃の純水１００ｍｌに加え、マグネチックスターラーで３分間攪拌し、その後吸引濾過した。得られた濾液のｐＨを堀場製作所製ｐＨメーターで測定した。結果を表１に示す。 (PH measurement) 2 g of the calcined nickel-lithium metal composite oxide was added to 100 ml of pure water at 25 ° C., stirred for 3 minutes with a magnetic stirrer, and then suction filtered. The pH of the obtained filtrate was measured with a pH meter manufactured by Horiba. The results are shown in Table 1.
（溶出Ｌｉ量、Ａｌ量の測定）上述濾液の１０ｇを１００ｍｌメスフラスコに採り、３５％の塩酸５ｍｌを加え１００ｍｌの標線まで純水を加える。この溶液を用いて、ＩＣＰ発光分析にて測定を行う。ＩＣＰの分析ではＡｌとＬｉを同時に測定する。測定結果を表１に示す。本測定の検出限界値は２．５ｐｐｍである。検出限界を下回る場合には、「<２．５ｐｐｍ」と表示する。検出限界を下回る場合、溶出性Ａｌを実質的に含まないことを意味する。"
［実施例１］
上述の方法で調整した焼成原料を焼成した。温度管理を以下のように行った。室温で昇温を開始した。１時間かけて３００℃まで昇温し温度が３００℃で０．５時間保持した。次に、１時間かけて５５０℃まで昇温し、温度５５０℃で２時間保持した。更に、１時間かけて７８０℃まで昇温し、温度７８０℃で４時間保持した後、１時間当たり８０℃の冷却割合で室温まで冷却した。上述の昇温パターンを「ｒｔ−３００−５５０−７８０」と呼ぶ。湿潤雰囲気を以下のように設定した。すなわち、酸素ガスを流量０．５L／ｍｉｎ．で供給する露点２０℃の湿潤雰囲気中で昇温を開始し、焼成工程終了までこの湿潤雰囲気を維持した。
［実施例２］
酸素ガスの流量を１L／ｍｉｎ．とした点以外は実施例１と同じ条件で焼成した。
［実施例３］
酸素ガス流量を５L／ｍｉｎ．とした点以外は実施例１と同じ条件で焼成した。
［実施例４］
酸素ガス流量を１L／ｍｉｎ．、露点を４０℃とした点以外は実施例１と同じ条件で焼成した。
［実施例５］
酸素ガス流量を１L／ｍｉｎ．、露点を６０℃とした点以外は実施例１と同じ条件で焼成した。
［実施例６］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥酸素中で昇温を開始し、温度が７８０℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例７］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が５５０℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例８］
昇温パターンは実施例１（ｒｔ−３００−５５０−７８０）と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が３００℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例９］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が１００℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例１０］
昇温パターンを変更した。すなわち、室温から昇温を開始し、２時間かけて２３０℃まで昇温し、続いて７８０℃まで０．５時間で急速に昇温し、温度７８０℃を２．５時間保持し焼成を行った。焼成後は成り行きで室温まで降温した。この昇温パターンを「ｒｔ−２３０−７８０」という。実施例１と同じく、露点４０℃の酸素ガス中で昇温を開始し、焼成工程終了までこの湿潤雰囲気を維持した。
［実施例１１］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。湿潤雰囲気の切り替えを行った。すなわち、露点４０℃の酸素ガス中で昇温を開始した。室温から２３０℃までの昇温、７８０℃までの昇温、温度７８０度での維持を、湿潤雰囲気下で行った。７８０℃での焼成が完了した時点で雰囲気を乾燥雰囲気に切り替えた。続いて成り行きで室温まで冷却した。
［実施例１２］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。湿潤雰囲気の切り替えを行った。すなわち、露点４０℃の酸素ガス中で昇温を開始した。温度を２３０℃から７８０℃まで連続的に上昇させながら、温度が５３０℃に達した時点で雰囲気を乾燥雰囲気に切り替えた。実施例１０と同様に７８０℃で焼成し、次いで冷却した。
［比較例１］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。焼成工程全部を乾燥雰囲気下で行った。
［比較例２］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。焼成工程全部を乾燥雰囲気下で行った。
［比較例３］
昇温パターンを変更した。すなわち、乾燥雰囲気中で昇温を開始した。室温から７８０℃まで１時間で急速に昇温し、温度７８０度で５時間保持し焼成を行った。この昇温パターンを「ｒｔ−７８０」という。
(Measurement of elution Li amount and Al amount) Take 10 g of the above filtrate in a 100 ml volumetric flask, add 5 ml of 35% hydrochloric acid, and add pure water to a 100 ml mark. Using this solution, measurement is performed by ICP emission spectrometry. In the ICP analysis, Al and Li are measured simultaneously. The measurement results are shown in Table 1. The detection limit value of this measurement is 2.5 ppm. When the value is below the detection limit, “<2.5 ppm” is displayed. When below the detection limit, it means that substantially no eluting Al is contained. "
[Example 1]
The firing raw material prepared by the above method was fired. The temperature control was performed as follows. Heating started at room temperature. The temperature was raised to 300 ° C. over 1 hour, and the temperature was maintained at 300 ° C. for 0.5 hour. Next, it heated up to 550 degreeC over 1 hour, and hold | maintained at the temperature of 550 degreeC for 2 hours. Furthermore, after heating up to 780 degreeC over 1 hour and hold | maintaining at the temperature of 780 degreeC for 4 hours, it cooled to room temperature at the cooling rate of 80 degreeC per hour. The above temperature rise pattern is referred to as “rt-300-550-780”. The wet atmosphere was set as follows. That is, oxygen gas was supplied at a flow rate of 0.5 L / min. The temperature rise was started in a humid atmosphere with a dew point of 20 ° C. supplied in step 1, and this wet atmosphere was maintained until the end of the firing step.
[Example 2]
The flow rate of oxygen gas is 1 L / min. It fired on the same conditions as Example 1 except the point made into.
[Example 3]
The oxygen gas flow rate was 5 L / min. It fired on the same conditions as Example 1 except the point made into.
[Example 4]
The oxygen gas flow rate is 1 L / min. Baking was performed under the same conditions as in Example 1 except that the dew point was 40 ° C.
[Example 5]
The oxygen gas flow rate is 1 L / min. Baking was performed under the same conditions as in Example 1 except that the dew point was 60 ° C.
[Example 6]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, heating was started in dry oxygen, and the atmosphere was switched to oxygen gas having a dew point of 40 ° C. when the temperature reached 780 ° C.
[Example 7]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, temperature increase was started in a dry atmosphere, and when the temperature reached 550 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 8]
The temperature rising pattern was the same as that in Example 1 (rt-300-550-780). Wet atmosphere was switched. That is, temperature increase was started in a dry atmosphere, and when the temperature reached 300 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 9]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, heating was started in a dry atmosphere, and when the temperature reached 100 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 10]
Changed heating pattern. That is, the temperature was raised from room temperature, raised to 230 ° C. over 2 hours, then rapidly raised to 780 ° C. in 0.5 hours, and maintained at 780 ° C. for 2.5 hours for firing. It was. After firing, the temperature dropped to room temperature. This temperature rise pattern is referred to as “rt-230-780”. As in Example 1, the temperature was raised in oxygen gas having a dew point of 40 ° C., and this wet atmosphere was maintained until the end of the firing step.
[Example 11]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. Wet atmosphere was switched. That is, the temperature increase was started in oxygen gas having a dew point of 40 ° C. The temperature was raised from room temperature to 230 ° C., the temperature was raised to 780 ° C., and the temperature was maintained at 780 ° C. in a wet atmosphere. At the time when the baking at 780 ° C. was completed, the atmosphere was switched to a dry atmosphere. Subsequently, it was cooled to room temperature.
[Example 12]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. Wet atmosphere was switched. That is, the temperature increase was started in oxygen gas having a dew point of 40 ° C. While the temperature was continuously increased from 230 ° C. to 780 ° C., the atmosphere was switched to a dry atmosphere when the temperature reached 530 ° C. It baked at 780 degreeC like Example 10, and then cooled.
[Comparative Example 1]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. All firing steps were performed in a dry atmosphere.
[Comparative Example 2]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. All firing steps were performed in a dry atmosphere.
[Comparative Example 3]
Changed heating pattern. That is, temperature increase was started in a dry atmosphere. The temperature was rapidly raised from room temperature to 780 ° C. in 1 hour, and kept at a temperature of 780 ° C. for 5 hours for firing. This temperature rise pattern is referred to as “rt-780”.
実施例と比較例の焼成工程の概要を表１に示す。実施例と比較例で得られたニッケルリチウム金属複合酸化物の分析結果を表２に示す。 Table 1 shows an outline of the firing steps of the examples and comparative examples. Table 2 shows the analysis results of the nickel lithium metal composite oxides obtained in Examples and Comparative Examples.
表１に示されるように、実施例１〜１２では、所定の焼成工程を経ることによって、ｐＨが低減され、実質的に溶出Ａｌを含まない低アルカリ性ニッケルリチウム金属複合酸化物粉体が得られた。 As shown in Table 1, in Examples 1 to 12, a low-alkaline nickel-lithium metal composite oxide powder that has a reduced pH and substantially does not contain eluted Al is obtained through a predetermined firing step. It was.
本発明では、従来行われていた正極活物質用のニッケルリチウム金属複合酸化物の製造方法における焼成工程の雰囲気ガスを制御するという、簡単な調節方法で、電池性能や正極製造にとって望ましい低アルカリ性ニッケルリチウム金属複合酸化物粉体を製造することに成功した。しかも、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体では、溶出性Al含有量も低減されており、このことによってもリチウムイオン電池の正極剤としての性能が向上されていると期待できる。本発明は、高容量のリチウムイオン電池の低コストでの製造に貢献すると期待される。 In the present invention, low alkaline nickel desirable for battery performance and positive electrode production is achieved by a simple adjustment method of controlling the atmospheric gas in the firing step in the conventional method for producing nickel lithium metal composite oxide for positive electrode active material. Succeeded in producing lithium metal composite oxide powder. Moreover, in the low alkaline nickel lithium metal composite oxide powder of the present invention, the eluting Al content is also reduced, and it can be expected that the performance as the positive electrode agent of the lithium ion battery is also improved. The present invention is expected to contribute to low-cost production of high capacity lithium ion batteries.
本発明は低アルカリニッケルリチウム金属複合酸化物粉体、これを含むリチウムイオン電池正極物質、該活物質を用いたリチウムイオン電池正極、この正極を有するリチウムイオン電池、及び上記低アルカリニッケルリチウム金属複合酸化物の製造方法に関する。 The present invention relates to a low alkali nickel lithium metal composite oxide powder, a lithium ion battery positive electrode material including the same, a lithium ion battery positive electrode using the active material, a lithium ion battery having the positive electrode, and the low alkali nickel lithium metal composite The present invention relates to an oxide manufacturing method.
スマートフォン、タブレット型パソコン等の小型電子機器の普及により、ユーザーが屋外で長時間これら小型電子機器を携帯し利用することは、もはや一般的になっている。そのため、これら小型電子機器の電源である電池には長時間の使用に耐える高容量の電池であることが求められており、そのような要求を満たすリチウムイオン二次電池が盛んに研究開発されている。同時に、スマートフォン、タブレット型パソコン等の小型電子機器の更なる高機能化、高性能化が図られており、そのような高機能・高性能小型電子機器では消費電力の増大が避けられない。したがって、電池の高容量化への要求がますます高まっている。 With the spread of small electronic devices such as smartphones and tablet computers, it is no longer common for users to carry and use these small electronic devices outdoors for a long time. For this reason, batteries that are the power sources of these small electronic devices are required to have a high capacity that can withstand long-term use, and lithium-ion secondary batteries that satisfy such requirements have been actively researched and developed. Yes. At the same time, small electronic devices such as smartphones and tablet computers are being further enhanced in function and performance, and such high-performance and high-performance small electronic devices cannot avoid increasing power consumption. Therefore, there is an increasing demand for higher battery capacity.
また、近年は、エネルギー受給に対する危機意識や環境志向の高まりよって、風力発電、メガソーラー発電、家庭用太陽光発電と言った、従来型の集中型発電所とは異なる独立分散型発電設備の設置が増えている。しかしながら、風力発電、太陽光発電等の自然エネルギーを利用した発電設備が従来の発電施設に比べて電気供給の安定性に劣るという問題は、未だ解決されていない。２０１１年３月１１日に発生した東日本大震災、その後に引き起こされた原子力発電所停止にかかる給電状況の悪化以来、地震等の災害発生時に事業所や家庭単位の電力確保が重要であることが広く認識されるようになってきた。このため、消費地点単位で電源確保を確保する定置用蓄電池に注目が集まっている。しかしながら、現在の技術によれば、このような定置用蓄電池によって電気容量を確保するためには非常に大きな蓄電設備が必要とされる。このため、日本の住宅環境においてはそのような蓄電設備は、現時点では実用性を欠く。 Also, in recent years, due to the growing awareness of energy crisis and environmental awareness, the installation of independent and decentralized power generation facilities, such as wind power generation, mega solar power generation, and home solar power generation, which are different from conventional centralized power plants. Is increasing. However, the problem that power generation facilities using natural energy such as wind power generation and solar power generation are inferior to the stability of electricity supply as compared with conventional power generation facilities has not yet been solved. Since the Great East Japan Earthquake that occurred on March 11, 2011 and the worsening of the power supply situation caused by the subsequent stoppage of nuclear power plants, it is widely important to secure power for business units and households when disasters such as earthquakes occur It has come to be recognized. For this reason, attention has been focused on stationary storage batteries that ensure the supply of power on a consumption point basis. However, according to the current technology, a very large power storage facility is required to secure electric capacity with such a stationary storage battery. For this reason, in the Japanese residential environment, such power storage equipment lacks utility at present.
更に自動車産業においては、エネルギー効率のよい電気自動車、ハイブリッド自動車に注目が集まり、これらの自動車の開発が盛んに行われている。しかしながら、電池容量の不足による航続距離の不十分さ、加えて市中における充電設備の絶対的不足という問題は解決されていない。そのため、現時点では、電気エネルギーだけで動く電気自動車は、ハイブリッド自動車ほどには普及していない。 Further, in the automobile industry, attention is focused on energy efficient electric vehicles and hybrid vehicles, and development of these vehicles is actively performed. However, the problem of insufficient cruising distance due to insufficient battery capacity and the absolute shortage of charging facilities in the city has not been solved. Therefore, at present, electric vehicles that run only on electric energy are not as popular as hybrid vehicles.
上述のような、電子機器、電力確保、自動車などの産業を支える共通の製品の一つがリチウムイオン電池である。上述のような問題点に共通する原因が、リチウムイオン電池の体積当たりの容量が足りないことにある。リチウムイオン電池の体積当たりの容量が足りないという問題を引き起こす大きな要因は、リチウムイオン二次電池に用いられる正極活物質の単位体積当たりの放電容量が小さいことである。 One of the common products that support industries such as electronic devices, power securing, and automobiles as described above is a lithium ion battery. A common cause of the above problems is that the capacity per volume of the lithium ion battery is insufficient. A major factor causing the problem that the capacity per volume of the lithium ion battery is insufficient is that the discharge capacity per unit volume of the positive electrode active material used in the lithium ion secondary battery is small.
リチウムイオン電池の正極活物質としては、コバルト酸リチウム（ＬＣＯ）に代表されるコバルト系正極活物質が用いられてきた。コバルト酸リチウムを用いて電極を作成すると、電極密度は１立方センチメートル当たり３．９ｇを超える大密度を達成できる。しかしその一方、コバルト酸リチウム自身の放電容量は実質１５０ｍＡｈ／ｇ程度と低い。 As a positive electrode active material of a lithium ion battery, a cobalt-based positive electrode active material typified by lithium cobaltate (LCO) has been used. When an electrode is made using lithium cobaltate, an electrode density of greater than 3.9 g per cubic centimeter can be achieved. However, on the other hand, the discharge capacity of lithium cobalt oxide itself is as low as about 150 mAh / g.
リチウムイオン電池の正極活物質としては、ＬＮＣＯ（Ｌｉ、Ｎｉ、Ｃｏの複合酸化物），特にＬＮＣＡＯ（Ｌｉ、Ｎｉ、Ｃｏ、Ａｌの複合酸化物）に代表されるニッケル系正極活物質も検討されている。ＬＮＣＡＯの単位重量当たりの放電容量はコバルト系正極活物質よりも大きく、１９０ｍＡｈ／ｇを超える。しかしその一方、このような正極活物質を用いて電極を作成する際の問題が指摘されている。すなわち、活物質とバインダーとからなるスラリーがゲル化し、このゲル化がスラリーの塗布性を悪化させるという問題がある。このゲル化は、強いアルカリ性を示す活物質がバインダーとして用いられるＰＶＤＦ（ポリビニリデンフルオライド系重合体）からフッ素を脱離させ、ＰＶＤＦ樹脂鎖の架橋が起こることに起因すると考えられている。そこで、ＬＮＣＡＯ（Ｌｉ、Ｎｉ、Ｃｏ、Ａｌの複合酸化物）に代表されるニッケル系正極活物質に含まれるアルカリ性物質を低減することが求められている。
リチウムイオン電池の正極活物質のｐＨを低減する手段としては、例えば、特許文献１には、正極活物質に特定の化合物を接触させて、正極活物質中に残存するアルカリ性化合物をアルカリ性の低い化合物に変換する方法が記載されている。特許文献２には、焼成後のニッケル酸リチウム粉末を高純度二酸化炭素ガスで処理する方法が記載されている。しかし、このような手段は、従来の製造工程に加えた新たな工程を必要とするために、コスト面で問題がある。
As a positive electrode active material of a lithium ion battery, a nickel-based positive electrode active material represented by LNCO (Li, Ni, Co composite oxide), particularly LNCAO (Li, Ni, Co, Al composite oxide) has been studied. ing. The discharge capacity per unit weight of LNCAO is larger than that of the cobalt-based positive electrode active material, and exceeds 190 mAh / g. On the other hand, however, problems in making an electrode using such a positive electrode active material have been pointed out. That is, there is a problem that the slurry composed of the active material and the binder is gelled, and this gelation deteriorates the applicability of the slurry. This gelation is considered to be caused by the fact that an active material exhibiting strong alkalinity desorbs fluorine from PVDF (polyvinylidene fluoride-based polymer) used as a binder and crosslinks the PVDF resin chain. Therefore, it is required to reduce an alkaline substance contained in a nickel-based positive electrode active material typified by LNCAO (Li, Ni, Co, Al composite oxide).
As a means for reducing the pH of the positive electrode active material of the lithium ion battery, for example, in Patent Document 1, a specific compound is brought into contact with the positive electrode active material, and the alkaline compound remaining in the positive electrode active material is reduced to a compound having low alkalinity. The method of converting to is described. Patent Document 2 describes a method of treating a fired lithium nickelate powder with high-purity carbon dioxide gas. However, since such a method requires a new process in addition to the conventional manufacturing process, there is a problem in cost.
本発明は、ＬＮＣＡＯに代表される正極活物質に残留するアルカリ性物質を低減し、電極製造や電池性能に有利な正極活物質を提供することを課題とする。また本発明では、より低コストで簡単な手段で低アルカリ性ＬＮＣＡＯ系正極活物質を得ることを目的とする。 An object of the present invention is to reduce the alkaline material remaining in a positive electrode active material typified by LNCAO and to provide a positive electrode active material advantageous for electrode production and battery performance. Another object of the present invention is to obtain a low alkaline LNCAO-based positive electrode active material by simple means at a lower cost.
本発明の発明者は、ＬＮＣＡＯに代表される正極活物質の製造において、特定の条件で焼成を行うこと、すなわち、露点０〜７０℃の湿潤雰囲気で焼成を行うことにより、ｐＨが低減された正極活物質を得た。しかも、本発明では、正極活物質から溶出するＡｌ量も低減することができ、正極活物質の安定性を向上することにも成功した。 The inventor of the present invention reduced the pH by producing a positive electrode active material typified by LNCAO by firing under specific conditions, that is, firing in a humid atmosphere with a dew point of 0 to 70 ° C. A positive electrode active material was obtained. Moreover, in the present invention, the amount of Al eluted from the positive electrode active material can also be reduced, and the stability of the positive electrode active material has been successfully improved.
すなわち本発明は以下のものである。 That is, the present invention is as follows.
（発明１）以下の一般式 （１）で表されるニッケルリチウム金属複合酸化物からなり、 (Invention 1) A nickel-lithium metal composite oxide represented by the following general formula (1):
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下であることを特徴とする、低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.) Hydrogen in the supernatant when 2 g of this was dispersed in 100 g of water The ion concentration is 11.7 or less in pH, and the Al concentration measured by ICP emission spectrometry of the supernatant when 2 g of the ion is dispersed in 100 g of water is 2.5 ppm or less. Alkaline nickel-lithium metal composite oxide powder.
（発明２）さらに、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＬｉ濃度が４５ｐｐｍ以下であることを特徴とする、発明１に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 2) The low alkaline nickel lithium according to Invention 1, wherein the Li concentration measured by ICP emission analysis of the supernatant when 2 g of the dispersion is dispersed in 100 g of water is 45 ppm or less. Metal composite oxide powder.
（発明３）一般式（１）におけるＭがＣｏであることを特徴とする、発明１または２に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 3) The low alkaline nickel lithium metal composite oxide powder according to Invention 1 or 2, wherein M in the general formula (1) is Co.
（発明４）一般式（１）におけるＮがＡｌであることを特徴とする、発明１〜３のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 4) The low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 1 to 3, wherein N in the general formula (1) is Al.
（発明５）一般式（１）における一般式（１）におけるＭがＣｏであり、かつ、ＮがＡｌであることを特徴とする、発明１〜４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体。 (Invention 5) The low alkaline nickel lithium metal according to any one of Inventions 1 to 4, wherein M in the general formula (1) in the general formula (1) is Co and N is Al. Composite oxide powder.
（発明６）発明１〜５のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体を含むことを特徴とする、リチウムイオン電池用正極活物質。 (Invention 6) A positive electrode active material for a lithium ion battery, comprising the low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 1 to 5.
（発明７）発明６に記載のリチウムイオン電池用正極活物質を用いることを特徴とする、リチウムイオン電池用正極。 (Invention 7) A positive electrode for a lithium ion battery, characterized in that the positive electrode active material for a lithium ion battery according to Invention 6 is used.
（発明８）発明７に記載のリチウムイオン電池用正極を備えることを特徴とする、リチリウムイオン電池。 (Invention 8) A lithium ion battery comprising the positive electrode for a lithium ion battery according to Invention 7.
（発明９）以下の一般式 （１）で表されるニッケルリチウム金属複合酸化物からなり、 (Invention 9) A nickel-lithium metal composite oxide represented by the following general formula (1):
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下である低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法であって、原料混合物の焼成工程の少なくとも一部を、露点が０〜７０℃である湿潤雰囲気ガス中で行うことを特徴とする、低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.) Hydrogen in the supernatant when 2 g of this was dispersed in 100 g of water Low alkaline nickel-lithium metal composite oxide having an ion concentration of 11.7 or less in pH and an Al concentration of 2.5 ppm or less measured by ICP emission analysis of the supernatant when 2 g of the solution is dispersed in 100 g of water A low-alkali nickel-lithium metal composite oxide powder, characterized in that at least a part of the firing step of the raw material mixture is performed in a humid atmosphere gas having a dew point of 0 to 70 ° C. Body manufacturing method.
（発明１０）さらに、低アルカリ性ニッケルリチウム金属複合酸化物粉体が、その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＬｉ濃度が４５ｐｐｍ以下であることを特徴とする、発明９に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 10) Further, in the low alkaline nickel lithium metal composite oxide powder, the Li concentration measured by ICP emission spectrometry of the supernatant when 2 g of the powder is dispersed in 100 g of water is 45 ppm or less. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder of invention 9.
（発明１１）一般式（１）におけるＭがＣｏであることを特徴とする、発明９または１０に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 11) The method for producing a low alkaline nickel lithium metal composite oxide powder according to Invention 9 or 10, wherein M in the general formula (1) is Co.
（発明１２）一般式（１）におけるＮがＡｌであることを特徴とする、発明９〜１１のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 12) The method for producing a low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 9 to 11, wherein N in the general formula (1) is Al.
（発明１３）一般式（１）における一般式（１）におけるＭがＣｏであり、かつ、ＮがＡｌであることを特徴とする、発明９〜１２のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 13) The low alkaline nickel lithium metal according to any one of Inventions 9 to 12, wherein M in the general formula (1) in the general formula (1) is Co and N is Al. A method for producing a composite oxide powder.
（発明１４）原料混合物の焼成工程の少なくとも一部を、露点が３０〜５０℃である湿潤雰囲気ガス中で行うことを特徴とする、発明９〜１３のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 14) The low alkaline nickel lithium metal according to any one of Inventions 9 to 13, wherein at least a part of the firing step of the raw material mixture is performed in a humid atmosphere gas having a dew point of 30 to 50 ° C. A method for producing a composite oxide powder.
（発明１５）焼成工程の全部を露点が０〜７０℃である湿潤雰囲気ガス中で行うことを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 15) A low alkaline nickel lithium metal composite oxide powder according to any one of Inventions 9 to 14, wherein the entire firing step is performed in a humid atmosphere gas having a dew point of 0 to 70 ° C. Production method.
（発明１６）焼成工程において、乾燥雰囲気で昇温を開始し、温度が最高温度に達する時点以前に焼成雰囲気を露点が０〜７０℃である湿潤雰囲気ガスに切り替えることを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 16) In the firing step, the temperature rise is started in a dry atmosphere, and the firing atmosphere is switched to a wet atmosphere gas having a dew point of 0 to 70 ° C. before the temperature reaches the maximum temperature. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder in any one of -14.
（発明１７）焼成工程において、露点が０〜７０℃である湿潤雰囲気ガス中で昇温を開始し、焼成後の冷却を開始する時点以前に焼成雰囲気を乾燥雰囲気ガスに切り替えることを特徴とする、発明９〜１４のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 17) In the firing step, the temperature rise is started in a humid atmosphere gas having a dew point of 0 to 70 ° C., and the firing atmosphere is switched to the dry atmosphere gas before starting the cooling after firing. The manufacturing method of the low alkaline nickel lithium metal complex oxide powder in any one of invention 9-14.
（発明１８）原料混合物の焼成工程を、原料の溶解工程、沈殿工程、ろ過・洗浄工程、乾燥工程を経た粉体混合工程の後に行うことを特徴とする、発明９〜１７のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 18) The invention according to any one of Inventions 9 to 17, wherein the firing step of the raw material mixture is performed after the raw material dissolution step, the precipitation step, the filtration / washing step, and the drying step. Of producing low alkaline nickel lithium metal composite oxide powder.
（発明１９）焼成工程の後に、さらに、低アルカリ性ニッケルリチウム金属複合酸化物粉体の解砕工程を設けることを特徴とする、発明９〜１８のいずれかに記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 (Invention 19) The low alkaline nickel lithium metal composite oxide according to any one of inventions 9 to 18, further comprising a crushing step of the low alkaline nickel lithium metal composite oxide powder after the firing step. A method for manufacturing powder.
本発明のニッケルリチウム金属複合酸化物粉体は、低アルカリ性であり、溶出性Al含有量が低減されている。 The nickel lithium metal composite oxide powder of the present invention has low alkalinity and has a reduced eluting Al content.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を構成するニッケルリチウム金属複合酸化物は、以下の一般式（１）で表される。 The nickel lithium metal composite oxide constituting the low alkaline nickel lithium metal composite oxide powder of the present invention is represented by the following general formula (1).
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を構成するニッケルリチウム金属複合酸化物は、好ましくは、上記一般式（１）においてMがCo、NがAlである、以下の一般式（２）で表される。
(In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu, and N is one or more metal elements selected from Al, W, Ta, and B) 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.)
The nickel lithium metal composite oxide constituting the low alkaline nickel lithium metal composite oxide powder of the present invention preferably has the following general formula (2) wherein M is Co and N is Al in the general formula (1). ).
（ただし式（２）中、０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
（製造方法）
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体は、以下の方法により製造することができる。
(In the formula (2), 0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10.)
(Production method)
The low alkaline nickel lithium metal composite oxide powder of the present invention can be produced by the following method.
（１．原料の溶解）原料としては、一般式（１）を構成する金属の、硫酸塩、硝酸塩などの可溶性金属塩を用いることができる。硝酸塩を用いた場合、硝酸性窒素を含む廃液処理にコストがかかるため、硝酸塩の使用は工業的には好ましくない。通常は一般式（１）を構成する金属の硫酸塩が用いられる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、まず、原料である硫酸ニッケル、硫酸コバルトのそれぞれを水に溶解する。 (1. Dissolution of raw materials) As raw materials, soluble metal salts such as sulfates and nitrates of metals constituting the general formula (1) can be used. When nitrate is used, it is costly to treat waste liquid containing nitrate nitrogen, so use of nitrate is not industrially preferable. Usually, a metal sulfate constituting the general formula (1) is used. In the method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention, first, each of nickel sulfate and cobalt sulfate as raw materials is dissolved in water.
（２．沈殿）硫酸ニッケル水溶液、硫酸コバルト水溶液、沈殿剤としての水酸化ナトリウムとアンモニア水を沈殿槽内で混合する。水酸化ニッケルと水酸化コバルトの共沈殿物が生成する。 (2. Precipitation) A nickel sulfate aqueous solution, a cobalt sulfate aqueous solution, sodium hydroxide as a precipitating agent and aqueous ammonia are mixed in a precipitation tank. A coprecipitate of nickel hydroxide and cobalt hydroxide is formed.
（３．濾過・洗浄）沈殿物を濾過し、水分を除去して水酸化物ケーキを分離する。水酸化物ケーキを水酸化ナトリウム水溶液で洗浄し、硫酸イオンを除去する。さらに水酸化物ケーキを純水で洗浄して水酸化ナトリウムを除去する。こうして水酸化ニッケルと水酸化コバルトからなる前駆体ケーキが得られる。 (3. Filtration / Washing) The precipitate is filtered to remove moisture and separate the hydroxide cake. The hydroxide cake is washed with an aqueous sodium hydroxide solution to remove sulfate ions. Further, the hydroxide cake is washed with pure water to remove sodium hydroxide. Thus, a precursor cake composed of nickel hydroxide and cobalt hydroxide is obtained.
（４．乾燥）前駆体ケーキを乾燥する。乾燥方法は、大気圧下での熱風乾燥、赤外線乾燥、真空乾燥などのいずれでもよい。真空乾燥を行うことにより短時間で乾燥することができる。前駆体中の水分が１重量％程度になるまで乾燥する。 (4. Drying) The precursor cake is dried. The drying method may be any of hot air drying under atmospheric pressure, infrared drying, vacuum drying, and the like. It can dry in a short time by performing vacuum drying. Dry until the water content in the precursor is about 1% by weight.
（５．粉体混合）乾燥後の前駆体粉末に、水酸化アルミニウムと水酸化リチウム粉末を加え、剪断力をかけて混合する。 (5. Powder mixing) Aluminum hydroxide and lithium hydroxide powder are added to the dried precursor powder and mixed by applying a shearing force.
（６．焼成）混合物を酸素存在下で焼成する。焼成により、以下の反応が起こる。 (6. Firing) The mixture is fired in the presence of oxygen. The following reaction occurs by firing.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法は、焼成工程の少なくとも一部を、湿潤雰囲気中で行うことを特徴とする。すなわち、本発明では、温度を上げて焼成工程を開始する時点から、最高温度に一定時間保持した後に冷却して焼成工程を終了する時点までの期間のうち、少なくとも１部分を、湿潤雰囲気中で行う。本発明の製造方法で採用される湿潤雰囲気は、露点が０〜７０℃、好ましくは３０〜５０℃の範囲にある、酸素含有気体である。酸素含有気体としては、酸素ガス、空気などが使用される。焼成工程において、最高温度は６５０〜８５０℃の範囲とし、この最高温度を２〜３０時間保持して焼成する。焼成の後、冷却する。こうして焼成工程が完了する。
The method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention is characterized in that at least a part of the firing step is performed in a humid atmosphere. That is, in the present invention, at least one part of the period from the time when the firing process is started by raising the temperature to the time when the firing process is finished after being held at the maximum temperature for a certain period of time is kept in a humid atmosphere. Do. The moist atmosphere employed in the production method of the present invention is an oxygen-containing gas having a dew point of 0 to 70 ° C, preferably 30 to 50 ° C. As the oxygen-containing gas, oxygen gas, air, or the like is used. In the firing step, the maximum temperature is in the range of 650 to 850 ° C., and the maximum temperature is maintained for 2 to 30 hours for firing. After firing, cool. Thus, the firing process is completed.
焼成工程のいずれの部分を湿潤雰囲気中で行うかは、特に制限は無い。焼成工程全部を湿潤雰囲気中で行ってもよい。乾燥雰囲気で焼成工程を開始し、後に湿潤雰囲気に切り替えてもよい。また、湿潤雰囲気で焼成工程を開始し、後に乾燥雰囲気に切り替えてもよい。 There is no particular limitation on which part of the firing step is performed in a humid atmosphere. The entire firing step may be performed in a humid atmosphere. The firing process may be started in a dry atmosphere and later switched to a wet atmosphere. Alternatively, the firing process may be started in a wet atmosphere and then switched to a dry atmosphere.
乾燥雰囲気で焼成工程を開始し、後に湿潤雰囲気に切り替える場合は、一般には、湿潤雰囲気への切り替えを最高温度に達する時点以前に行う。すなわち、昇温中か、あるいは最高温度に達した時点で行う。好ましい切り替え時は昇温中である。 When starting the firing process in a dry atmosphere and switching to a wet atmosphere later, the switch to the wet atmosphere is generally performed before the time when the maximum temperature is reached. That is, it is performed during the temperature rise or when the maximum temperature is reached. During preferred switching, the temperature is rising.
湿潤雰囲気で焼成工程を開始し、後に乾燥雰囲気に切り替える場合は、一般には、乾燥雰囲気への切り替えは、冷却を開始する時点以前に行う。すなわち、昇温中、最高温度が保持されている間、あるいは、最高温度に保持して焼成を終了した後に冷却を開始する時点で行う。 When the firing process is started in a wet atmosphere and then switched to a dry atmosphere, generally, the switch to the dry atmosphere is performed before the start of cooling. That is, it is performed while the maximum temperature is maintained during the temperature increase, or when the cooling is started after the baking is completed while maintaining the maximum temperature.
焼成雰囲気への水分供給方法は、所望の露点を達成できる方法であれば、いずれも採用することができる。例えば、酸素含有気体を洗気瓶等を用いて液体の水にバブリングすることによって雰囲気に使用する気体に水分を供給する方法、酸素含有気体に噴霧器等を用いて霧状の水を供給し、所望する露点の雰囲気の気体を供給する方法が利用できる。工業生産現場においては、焼成原料である水酸化ニッケル、水酸化リチウム及び水酸化金属の混合物から焼成中に発生する水分の利用、上述の水分供給方法と、水分を含まない雰囲気気体供給を組み合わせて、焼成雰囲気の露点を所望の範囲に調整する。 Any method can be employed as a method for supplying moisture to the firing atmosphere as long as a desired dew point can be achieved. For example, a method of supplying moisture to the gas used for the atmosphere by bubbling oxygen-containing gas to liquid water using a washing bottle, etc., supplying atomized water to the oxygen-containing gas using a sprayer or the like, A method of supplying a gas having a desired dew point atmosphere can be used. In industrial production sites, the use of moisture generated during firing from a mixture of nickel hydroxide, lithium hydroxide and metal hydroxide as firing raw materials, the above-described moisture supply method, and the combination of atmospheric gas supply without moisture The dew point of the firing atmosphere is adjusted to a desired range.
このような特定の湿潤雰囲条件で焼成することにより、本発明では焼成後のニッケルリチウム金属複合酸化物に含まれる強アルカリ物質を低減することができる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体２ｇを１００ｇの水に分散させた場合、分散液上澄のｐＨは１１．７以下に低減される。また、ＩＣＰ発光分析法による分散液上澄のＬｉ含有量は、４５ｐｐｍ以下である。 By firing under such specific wet atmosphere conditions, in the present invention, the strong alkaline substance contained in the nickel-lithium metal composite oxide after firing can be reduced. When 2 g of the low alkaline nickel lithium metal composite oxide powder of the present invention is dispersed in 100 g of water, the pH of the dispersion supernatant is reduced to 11.7 or lower. Moreover, Li content of the dispersion supernatant liquid by ICP emission analysis is 45 ppm or less.
湿潤雰囲気中での焼成によって低アルカリ性ニッケルリチウム金属複合酸化物粉体が得られる理由は現時点では完全には解明されていない。焼成雰囲気中の水分によって、ニッケルリチウム金属複合酸化物の表面に存在する酸化リチウムの形態で存在するリチウムイオンが、水酸化リチウムの形態で存在する移動性の高いリチウムイオンに変化すること、この変化によってリチウムイオンがニッケルリチウム金属複合酸化物の表面からその結晶内に移動すること、リチウムイオンの結晶内への均質化が水へ溶出するリチウムイオン濃度の減少をもたらすこと、が推測されている。 The reason why low alkaline nickel lithium metal composite oxide powder can be obtained by firing in a humid atmosphere has not been fully elucidated at this time. Due to moisture in the firing atmosphere, the lithium ion present in the form of lithium oxide present on the surface of the nickel-lithium metal composite oxide changes to a highly mobile lithium ion present in the form of lithium hydroxide. It is speculated that the lithium ions move from the surface of the nickel lithium metal composite oxide into the crystal due to the above, and that the homogenization of the lithium ions into the crystal results in a decrease in the concentration of lithium ions eluted into water.
このように低アルカリ性を示す本発明のニッケルリチウム金属複合酸化物は、リチウムイオン電池正極剤スラリーにバインダーとして含まれるＰＶＤＦとの反応性が低い。このため、本発明のニッケルリチウム金属複合酸化物を正極活物質として使用した場合、正極製造時の正極剤スラリーのゲル化が起こりにくく、スラリーの塗工工程に問題が生じない。 Thus, the nickel lithium metal composite oxide of the present invention showing low alkalinity has low reactivity with PVDF contained as a binder in the lithium ion battery positive electrode slurry. For this reason, when the nickel lithium metal composite oxide of the present invention is used as the positive electrode active material, gelation of the positive electrode agent slurry during the production of the positive electrode hardly occurs, and no problem occurs in the slurry coating process.
その一方で、このような特定の湿潤雰囲気中で焼成することにより、本発明では焼成後のニッケルリチウム金属複合酸化物に含まれる溶出性Ａｌ化合物の量も低減することができる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体２ｇを１００ｇの水に分散させた場合、ＩＣＰ発光分析法による分散液上澄のＡｌ含有量は、検出限界２．５ｐｐｍを下回る。 On the other hand, by firing in such a specific moist atmosphere, in the present invention, the amount of the eluting Al compound contained in the nickel-lithium metal composite oxide after firing can also be reduced. When 2 g of the low alkaline nickel lithium metal composite oxide powder of the present invention is dispersed in 100 g of water, the Al content of the dispersion supernatant by ICP emission analysis is below the detection limit of 2.5 ppm.
このように溶出性Ａｌ含有量の低い本発明のニッケルリチウム金属複合酸化物をリチウムイオン電池の正極活物質として用いた場合、電池のサイクル特性及び熱安定性が向上すると考えられる。これはAlイオンがニッケルリチウム金属複合酸化物の層状構造中に存在するＮｉイオンと同型置換することにより、ニッケル系正極材の欠点の一つである結晶構造の不安定性が抑制され、層状構造の安定化に寄与すると考えられる為である。 Thus, when the nickel lithium metal composite oxide of the present invention having a low eluting Al content is used as a positive electrode active material of a lithium ion battery, it is considered that the cycle characteristics and thermal stability of the battery are improved. This is because Al ions are replaced by the same type of Ni ions present in the layered structure of nickel-lithium metal composite oxide, so that the instability of the crystal structure, which is one of the disadvantages of nickel-based positive electrode materials, is suppressed. This is because it is thought to contribute to stabilization.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、焼成工程の少なくとも一部分を上述の湿潤雰囲気下で行うことによって、焼成後のニッケルリチウム金属複合酸化物のｐＨが低減し、溶出性Ａｌ含有量も低減する。 In the method for producing a low alkaline nickel lithium metal composite oxide powder of the present invention, the pH of the nickel lithium metal composite oxide after firing is reduced and eluted by performing at least a part of the firing step in the above-mentioned wet atmosphere. The Al content is also reduced.
（７．解砕）本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法では、焼成工程の後に、必要に応じて、さらに解砕工程を設けることができる。解砕工程では、ジェットミルなどの解砕機を用いて、焼成後の低アルカリ性ニッケルリチウム金属複合酸化物粉体の凝集した粒子を解砕する。適度に細粒化されたニッケルリチウム金属複合酸化物を用いると、均一で塗布性に優れる正極剤スラリーが得られる。このような正極剤スラリーにより、正極電極の生産効率を向上させることができる。しかも、正極活物質のイオン放出性も安定化され、電池性能も向上する。 (7. Crushing) In the method for producing the low alkaline nickel lithium metal composite oxide powder of the present invention, a crushing step can be further provided as necessary after the firing step. In the pulverization step, the aggregated particles of the low alkaline nickel lithium metal composite oxide powder after calcination are pulverized using a pulverizer such as a jet mill. When a nickel-lithium metal composite oxide finely grained is used, a uniform positive electrode slurry having excellent coating properties can be obtained. The positive electrode slurry can improve the production efficiency of the positive electrode. In addition, the ion release property of the positive electrode active material is stabilized, and the battery performance is improved.
本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体は、リチウムイオン電池の正極活物質として利用できる。本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体のみでリチウムイオン電池の正極活物質を構成してもよいし、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体に、その長所が発現する程度の量で他のニッケルリチウム金属複合酸化物を混合してもよい。例えば、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体５０重量部と、本発明以外のリチウムイオン電池二次電池用正極活物質５０重量部とを混合したものを正極活物質として用いることができる。リチウムイオン電池の正極を製造する場合には、上述の本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体を含む正極活物質、導電助剤、バインダー、分散用有機溶媒を加えて正極用合剤スラリーを調製し、電極に塗布する。 The low alkaline nickel lithium metal composite oxide powder of the present invention can be used as a positive electrode active material of a lithium ion battery. The positive electrode active material of the lithium ion battery may be composed only of the low alkaline nickel lithium metal composite oxide powder of the present invention, and the advantages are manifested in the low alkaline nickel lithium metal composite oxide powder of the present invention. Other nickel lithium metal composite oxides may be mixed in a certain amount. For example, a mixture of 50 parts by weight of the low alkaline nickel lithium metal composite oxide powder of the present invention and 50 parts by weight of a positive electrode active material for a lithium ion battery secondary battery other than the present invention is used as the positive electrode active material. it can. When producing a positive electrode of a lithium ion battery, a positive electrode active material containing the above-mentioned low alkaline nickel lithium metal composite oxide powder of the present invention, a conductive additive, a binder, and an organic solvent for dispersion are added to mix the positive electrode. A slurry is prepared and applied to the electrode.
以下の方法で、低アルカリ性ニッケルリチウム金属複合酸化物前駆体を製造し、露点を調節した湿潤雰囲気中で焼成して、低アルカリ性ニッケルリチウム金属複合酸化物粉体を製造した。 A low alkaline nickel lithium metal composite oxide precursor was produced by the following method and fired in a humid atmosphere with a controlled dew point to produce a low alkaline nickel lithium metal composite oxide powder.
（焼成原料の調製）硫酸ニッケル及び硫酸コバルトを溶解させた水溶液に水酸化ナトリウム水溶液を加え、生じた沈殿を濾過、洗浄、乾燥することによりニッケル−コバルト複合水酸化物を得た。このニッケル−コバルト複合水酸化物７２．９ｇに水酸化リチウム２０．３ｇと水酸化アルミニウム４．８ｇを粉体で混合し焼成原料とした。この焼成原料をこの焼成原料３０ｇをアルミナボートに取り、内径５０ｍｍの石英管を設置した電気管状炉内に設置して、後述の実施例、比較例の操作に用いた。 (Preparation of calcination raw material) A sodium hydroxide aqueous solution was added to an aqueous solution in which nickel sulfate and cobalt sulfate were dissolved, and the resulting precipitate was filtered, washed and dried to obtain a nickel-cobalt composite hydroxide. Lithium hydroxide (20.3 g) and aluminum hydroxide (4.8 g) were mixed in powder form with 72.9 g of this nickel-cobalt composite hydroxide to obtain a calcined raw material. This calcined raw material was placed in an electric tubular furnace in which 30 g of this calcined raw material was placed in an alumina boat and a quartz tube having an inner diameter of 50 mm was installed, and used for the operations of Examples and Comparative Examples described later.
（焼成時雰囲気の露点調製）２０℃に保温した水を入れた洗気瓶を２本用意し各々を直列に接続する。この２本の洗気瓶を通した気体を、露点２０℃の気体と定義する。露点４０℃の気体は上記の水に４０℃の水を用い、露点６０℃の気体は上記の水に６０℃の水を用いた。気体として酸素を用いた。 (Preparation of dew point of atmosphere during firing) Prepare two washing bottles containing water kept at 20 ° C. and connect them in series. The gas that has passed through the two washing bottles is defined as a gas having a dew point of 20 ° C. A gas having a dew point of 40 ° C. used 40 ° C. water as the water, and a gas having a dew point of 60 ° C. used 60 ° C. water as the water. Oxygen was used as the gas.
（焼成）上述焼成原料を設置した電気管状炉内に、露点を制御した酸素ガスを導入し、最高温度７８０℃で焼成したものを正極活物質とした。 (Baking) A positive electrode active material was obtained by introducing oxygen gas with a controlled dew point into an electric tubular furnace in which the above-mentioned baking raw material was installed and baking at a maximum temperature of 780 ° C.
焼成後のニッケルリチウム金属複合酸化物を以下の方法で分析、評価した。 The nickel lithium metal composite oxide after firing was analyzed and evaluated by the following method.
（ｐH測定）焼成後のニッケルリチウム金属複合酸化物２ｇを２５℃の純水１００ｍｌに加え、マグネチックスターラーで３分間攪拌し、その後吸引濾過した。得られた濾液のｐＨを堀場製作所製ｐＨメーターで測定した。結果を表１に示す。 (PH measurement) 2 g of the calcined nickel-lithium metal composite oxide was added to 100 ml of pure water at 25 ° C., stirred for 3 minutes with a magnetic stirrer, and then suction filtered. The pH of the obtained filtrate was measured with a pH meter manufactured by Horiba. The results are shown in Table 1.
（溶出Ｌｉ量、Ａｌ量の測定）上述濾液の１０ｇを１００ｍｌメスフラスコに採り、３５％の塩酸５ｍｌを加え１００ｍｌの標線まで純水を加える。この溶液を用いて、ＩＣＰ発光分析にて測定を行う。ＩＣＰの分析ではＡｌとＬｉを同時に測定する。測定結果を表１に示す。本測定の検出限界値は２．５ｐｐｍである。検出限界を下回る場合には、「<２．５ｐｐｍ」と表示する。検出限界を下回る場合、溶出性Ａｌを実質的に含まないことを意味する。"
［実施例１］
上述の方法で調整した焼成原料を焼成した。温度管理を以下のように行った。室温で昇温を開始した。１時間かけて３００℃まで昇温し温度が３００℃で０．５時間保持した。次に、１時間かけて５５０℃まで昇温し、温度５５０℃で２時間保持した。更に、１時間かけて７８０℃まで昇温し、温度７８０℃で４時間保持した後、１時間当たり８０℃の冷却割合で室温まで冷却した。上述の昇温パターンを「ｒｔ−３００−５５０−７８０」と呼ぶ。湿潤雰囲気を以下のように設定した。すなわち、酸素ガスを流量０．５L／ｍｉｎ．で供給する露点２０℃の湿潤雰囲気中で昇温を開始し、焼成工程終了までこの湿潤雰囲気を維持した。
［実施例２］
酸素ガスの流量を１L／ｍｉｎ．とした点以外は実施例１と同じ条件で焼成した。
［実施例３］
酸素ガス流量を５L／ｍｉｎ．とした点以外は実施例１と同じ条件で焼成した。
［実施例４］
酸素ガス流量を１L／ｍｉｎ．、露点を４０℃とした点以外は実施例１と同じ条件で焼成した。
［実施例５］
酸素ガス流量を１L／ｍｉｎ．、露点を６０℃とした点以外は実施例１と同じ条件で焼成した。
［実施例６］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥酸素中で昇温を開始し、温度が７８０℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例７］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が５５０℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例８］
昇温パターンは実施例１（ｒｔ−３００−５５０−７８０）と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が３００℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例９］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。湿潤雰囲気の切り替えを行った。すなわち、乾燥雰囲気中で昇温を開始し、温度が１００℃になった時点で雰囲気を露点４０℃の酸素ガスに切り替えた。
［実施例１０］
昇温パターンを変更した。すなわち、室温から昇温を開始し、２時間かけて２３０℃まで昇温し、続いて７８０℃まで０．５時間で急速に昇温し、温度７８０℃を２．５時間保持し焼成を行った。焼成後は成り行きで室温まで降温した。この昇温パターンを「ｒｔ−２３０−７８０」という。実施例１と同じく、露点４０℃の酸素ガス中で昇温を開始し、焼成工程終了までこの湿潤雰囲気を維持した。
［実施例１１］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。湿潤雰囲気の切り替えを行った。すなわち、露点４０℃の酸素ガス中で昇温を開始した。室温から２３０℃までの昇温、７８０℃までの昇温、温度７８０度での維持を、湿潤雰囲気下で行った。７８０℃での焼成が完了した時点で雰囲気を乾燥雰囲気に切り替えた。続いて成り行きで室温まで冷却した。
［実施例１２］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。湿潤雰囲気の切り替えを行った。すなわち、露点４０℃の酸素ガス中で昇温を開始した。温度を２３０℃から７８０℃まで連続的に上昇させながら、温度が５３０℃に達した時点で雰囲気を乾燥雰囲気に切り替えた。実施例１０と同様に７８０℃で焼成し、次いで冷却した。
［比較例１］
昇温パターン（ｒｔ−３００−５５０−７８０）は実施例１と同じとした。焼成工程全部を乾燥雰囲気下で行った。
［比較例２］
昇温パターン（ｒｔ−２３０−７８０）は実施例１０と同じとした。焼成工程全部を乾燥雰囲気下で行った。
［比較例３］
昇温パターンを変更した。すなわち、乾燥雰囲気中で昇温を開始した。室温から７８０℃まで１時間で急速に昇温し、温度７８０度で５時間保持し焼成を行った。この昇温パターンを「ｒｔ−７８０」という。
(Measurement of elution Li amount and Al amount) Take 10 g of the above filtrate in a 100 ml volumetric flask, add 5 ml of 35% hydrochloric acid, and add pure water to a 100 ml mark. Using this solution, measurement is performed by ICP emission spectrometry. In the ICP analysis, Al and Li are measured simultaneously. The measurement results are shown in Table 1. The detection limit value of this measurement is 2.5 ppm. When the value is below the detection limit, “<2.5 ppm” is displayed. When below the detection limit, it means that substantially no eluting Al is contained. "
[Example 1]
The firing raw material prepared by the above method was fired. The temperature control was performed as follows. Heating started at room temperature. The temperature was raised to 300 ° C. over 1 hour, and the temperature was maintained at 300 ° C. for 0.5 hour. Next, it heated up to 550 degreeC over 1 hour, and hold | maintained at the temperature of 550 degreeC for 2 hours. Furthermore, after heating up to 780 degreeC over 1 hour and hold | maintaining at the temperature of 780 degreeC for 4 hours, it cooled to room temperature at the cooling rate of 80 degreeC per hour. The above temperature rise pattern is referred to as “rt-300-550-780”. The wet atmosphere was set as follows. That is, oxygen gas was supplied at a flow rate of 0.5 L / min. The temperature rise was started in a humid atmosphere with a dew point of 20 ° C. supplied in step 1, and this wet atmosphere was maintained until the end of the firing step.
[Example 2]
The flow rate of oxygen gas is 1 L / min. It fired on the same conditions as Example 1 except the point made into.
[Example 3]
The oxygen gas flow rate was 5 L / min. It fired on the same conditions as Example 1 except the point made into.
[Example 4]
The oxygen gas flow rate is 1 L / min. Baking was performed under the same conditions as in Example 1 except that the dew point was 40 ° C.
[Example 5]
The oxygen gas flow rate is 1 L / min. Baking was performed under the same conditions as in Example 1 except that the dew point was 60 ° C.
[Example 6]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, heating was started in dry oxygen, and the atmosphere was switched to oxygen gas having a dew point of 40 ° C. when the temperature reached 780 ° C.
[Example 7]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, temperature increase was started in a dry atmosphere, and when the temperature reached 550 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 8]
The temperature rising pattern was the same as that in Example 1 (rt-300-550-780). Wet atmosphere was switched. That is, temperature increase was started in a dry atmosphere, and when the temperature reached 300 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 9]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. Wet atmosphere was switched. That is, heating was started in a dry atmosphere, and when the temperature reached 100 ° C., the atmosphere was switched to oxygen gas having a dew point of 40 ° C.
[Example 10]
Changed heating pattern. That is, the temperature was raised from room temperature, raised to 230 ° C. over 2 hours, then rapidly raised to 780 ° C. in 0.5 hours, and maintained at 780 ° C. for 2.5 hours for firing. It was. After firing, the temperature dropped to room temperature. This temperature rise pattern is referred to as “rt-230-780”. As in Example 1, the temperature was raised in oxygen gas having a dew point of 40 ° C., and this wet atmosphere was maintained until the end of the firing step.
[Example 11]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. Wet atmosphere was switched. That is, the temperature increase was started in oxygen gas having a dew point of 40 ° C. The temperature was raised from room temperature to 230 ° C., the temperature was raised to 780 ° C., and the temperature was maintained at 780 ° C. in a wet atmosphere. At the time when the baking at 780 ° C. was completed, the atmosphere was switched to a dry atmosphere. Subsequently, it was cooled to room temperature.
[Example 12]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. Wet atmosphere was switched. That is, the temperature increase was started in oxygen gas having a dew point of 40 ° C. While the temperature was continuously increased from 230 ° C. to 780 ° C., the atmosphere was switched to a dry atmosphere when the temperature reached 530 ° C. It baked at 780 degreeC like Example 10, and then cooled.
[Comparative Example 1]
The temperature rise pattern (rt-300-550-780) was the same as that in Example 1. All firing steps were performed in a dry atmosphere.
[Comparative Example 2]
The temperature rise pattern (rt-230-780) was the same as that in Example 10. All firing steps were performed in a dry atmosphere.
[Comparative Example 3]
Changed heating pattern. That is, temperature increase was started in a dry atmosphere. The temperature was rapidly raised from room temperature to 780 ° C. in 1 hour, and kept at a temperature of 780 ° C. for 5 hours for firing. This temperature rise pattern is referred to as “rt-780”.
実施例と比較例の焼成工程の概要を表１に示す。実施例と比較例で得られたニッケルリチウム金属複合酸化物の分析結果を表２に示す。 Table 1 shows an outline of the firing steps of the examples and comparative examples. Table 2 shows the analysis results of the nickel lithium metal composite oxides obtained in Examples and Comparative Examples.
表１に示されるように、実施例１〜１２では、所定の焼成工程を経ることによって、ｐＨが低減され、実質的に溶出Ａｌを含まない低アルカリ性ニッケルリチウム金属複合酸化物粉体が得られた。 As shown in Table 1, in Examples 1 to 12, a low-alkaline nickel-lithium metal composite oxide powder that has a reduced pH and substantially does not contain eluted Al is obtained through a predetermined firing step. It was.
本発明では、従来行われていた正極活物質用のニッケルリチウム金属複合酸化物の製造方法における焼成工程の雰囲気ガスを制御するという、簡単な調節方法で、電池性能や正極製造にとって望ましい低アルカリ性ニッケルリチウム金属複合酸化物粉体を製造することに成功した。しかも、本発明の低アルカリ性ニッケルリチウム金属複合酸化物粉体では、溶出性Al含有量も低減されており、このことによってもリチウムイオン電池の正極剤としての性能が向上されていると期待できる。本発明は、高容量のリチウムイオン電池の低コストでの製造に貢献すると期待される。 In the present invention, low alkaline nickel desirable for battery performance and positive electrode production is achieved by a simple adjustment method of controlling the atmospheric gas in the firing step in the conventional method for producing nickel lithium metal composite oxide for positive electrode active material. Succeeded in producing lithium metal composite oxide powder. Moreover, in the low alkaline nickel lithium metal composite oxide powder of the present invention, the eluting Al content is also reduced, and it can be expected that the performance as the positive electrode agent of the lithium ion battery is also improved. The present invention is expected to contribute to low-cost production of high capacity lithium ion batteries.
Claims (19)
０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、
その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下であることを特徴とする、低アルカリ性ニッケルリチウム金属複合酸化物粉体。 It consists of nickel lithium metal composite oxide represented by the following general formula (1),
0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10. )
When the 2 g of the dispersion is dispersed in 100 g of water, the hydrogen ion concentration in the supernatant is 11.7 or less in pH,
A low alkaline nickel-lithium metal composite oxide powder characterized by having an Al concentration of 2.5 ppm or less measured by ICP emission analysis of the supernatant when 2 g thereof is dispersed in 100 g of water.
（ただし式（１）中、Ｍは、Ｃｏ，Ｍｎ，Ｆｅ、Ｃｕから選ばれる１つ以上の金属元素であり、
ＮはＡｌ、Ｗ、Ｔａ、Ｂから選ばれる１つ以上の金属元素であり、
０．９０＜ｘ＜１．１０、０．０１＜ｙ＜０．１５、０．００５＜ｚ＜０．１０である。）
その２ｇを１００ｇの水に分散させた際の上澄の水素イオン濃度がｐＨで１１．７以下であり、
その２ｇを１００ｇの水に分散させた際の上澄のＩＣＰ発光分析法で測定したＡｌ濃度が２．５ｐｐｍ以下である低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法であって、
原料混合物の焼成工程の少なくとも一部を、露点が０〜７０℃である湿潤雰囲気ガス中で行うことを特徴とする、
低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 It consists of nickel lithium metal composite oxide represented by the following general formula (1),
(In the formula (1), M is one or more metal elements selected from Co, Mn, Fe, and Cu;
N is one or more metal elements selected from Al, W, Ta, and B,
0.90 <x <1.10, 0.01 <y <0.15, 0.005 <z <0.10. )
When the 2 g of the dispersion is dispersed in 100 g of water, the hydrogen ion concentration in the supernatant is 11.7 or less in pH,
A method for producing a low alkaline nickel lithium metal composite oxide powder having an Al concentration of 2.5 ppm or less measured by ICP emission analysis of the supernatant when 2 g of the dispersion is dispersed in 100 g of water,
Performing at least part of the firing step of the raw material mixture in a humid atmosphere gas having a dew point of 0 to 70 ° C.,
A method for producing a low alkaline nickel lithium metal composite oxide powder.
請求項９〜１４のいずれか１項に記載の低アルカリ性ニッケルリチウム金属複合酸化物粉体の製造方法。 The entire firing process is performed in a humid atmosphere gas having a dew point of 0 to 70 ° C.,
The manufacturing method of the low alkaline nickel lithium metal complex oxide powder of any one of Claims 9-14.
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| JP2018118891A (en) * | 2017-01-27 | 2018-08-02 | ユミコア | High-performance positive electrode active material for lithium ion batteries and method for producing the same |
| WO2019087558A1 (en) * | 2017-10-30 | 2019-05-09 | 住友金属鉱山株式会社 | Positive electrode active material for nonaqueous electrolyte secondary batteries, method for producing positive electrode active material for nonaqueous electrolyte secondary batteries, and method for evaluating lithium metal composite oxide powder |
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| CN114127994B (en) * | 2019-07-18 | 2023-05-23 | 株式会社丰田自动织机 | Positive electrode active material in which aluminum is uniformly dispersed |
| WO2023276872A1 (en) * | 2021-06-28 | 2023-01-05 | 住友化学株式会社 | Method for producing lithium metal composite oxide |
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