JP2023044635A - Zinc foil and manufacturing method thereof, negative electrode material and battery - Google Patents
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- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims abstract description 155
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000007773 negative electrode material Substances 0.000 title claims description 11
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 61
- 239000011701 zinc Substances 0.000 claims abstract description 61
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 51
- 238000000151 deposition Methods 0.000 claims abstract description 7
- 229910052797 bismuth Inorganic materials 0.000 claims description 17
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 17
- 239000011888 foil Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 abstract description 8
- 239000003792 electrolyte Substances 0.000 abstract description 7
- 239000000243 solution Substances 0.000 abstract description 5
- 230000002829 reductive effect Effects 0.000 abstract description 3
- 229910052751 metal Inorganic materials 0.000 description 22
- 238000005868 electrolysis reaction Methods 0.000 description 18
- 239000002184 metal Substances 0.000 description 12
- 238000006722 reduction reaction Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 230000003746 surface roughness Effects 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 8
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 238000004993 emission spectroscopy Methods 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 229910052793 cadmium Inorganic materials 0.000 description 3
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- -1 hydrogen ions Chemical class 0.000 description 3
- 238000011835 investigation Methods 0.000 description 3
- 238000013507 mapping Methods 0.000 description 3
- QELJHCBNGDEXLD-UHFFFAOYSA-N nickel zinc Chemical compound [Ni].[Zn] QELJHCBNGDEXLD-UHFFFAOYSA-N 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000004070 electrodeposition Methods 0.000 description 2
- 229910052733 gallium Inorganic materials 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 229910000457 iridium oxide Inorganic materials 0.000 description 2
- 230000000873 masking effect Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- RXPAJWPEYBDXOG-UHFFFAOYSA-N hydron;methyl 4-methoxypyridine-2-carboxylate;chloride Chemical compound Cl.COC(=O)C1=CC(OC)=CC=N1 RXPAJWPEYBDXOG-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- WJZHMLNIAZSFDO-UHFFFAOYSA-N manganese zinc Chemical compound [Mn].[Zn] WJZHMLNIAZSFDO-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 229910001925 ruthenium oxide Inorganic materials 0.000 description 1
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 150000003752 zinc compounds Chemical class 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
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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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- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は、亜鉛箔及びその製造方法に関する。また本発明は、該亜鉛箔を用いた負極材料及び電池に関する。 The present invention relates to a zinc foil and its manufacturing method. The present invention also relates to a negative electrode material and a battery using the zinc foil.
電池の負極材料の一つである亜鉛は標準電極電位が低いことから、亜鉛を用いた電池はその起電力を高めることが可能である。また亜鉛は高体積容量密度を有することから、亜鉛を用いた電池はその容量を高めることが可能である。亜鉛を負極材料として用いた電池として代表的なものとしてマンガン一次電池が挙げられる。例えば特許文献１には、亜鉛地金にビスマスを添加した亜鉛合金を圧延してなる負極缶を備えたマンガン乾電池が記載されている。 Since zinc, which is one of the negative electrode materials for batteries, has a low standard electrode potential, batteries using zinc can increase the electromotive force. Also, since zinc has a high volume capacity density, a battery using zinc can increase its capacity. A typical battery using zinc as a negative electrode material is a manganese primary battery. For example, Patent Literature 1 describes a manganese dry battery having a negative electrode can made by rolling a zinc alloy obtained by adding bismuth to a zinc base metal.
また本発明者は先に、亜鉛を母材とし、所定量のビスマスを含む電解亜鉛箔を一次電池用の負極活物質として用いることを提案した（特許文献２）。 In addition, the present inventor previously proposed the use of an electrolytic zinc foil containing zinc as a base material and containing a predetermined amount of bismuth as a negative electrode active material for a primary battery (Patent Document 2).
本発明者が先に提案した特許文献２に記載の亜鉛箔を負極材料として用いた電池は、従来の電池に比して高性能のものとなる。しかし、電池の性能向上の要求は依然として高く、特に放電特性が良好な電池が求められている。
したがって本発明の課題は、これまでの電池に比して高レートでの放電特性に優れた電池を実現し得る負極材料を提供することにある。
A battery using the zinc foil described in Patent Document 2 proposed by the present inventor as a negative electrode material has higher performance than conventional batteries. However, the demand for improved battery performance is still high, and batteries with particularly good discharge characteristics are in demand.
Accordingly, an object of the present invention is to provide a negative electrode material that can realize a battery having excellent discharge characteristics at a high rate compared to conventional batteries.
本発明は、ＪＩＳ Ｂ０６０１－２００１に準拠して測定された算術平均粗さＲａが、少なくとも一方の面において１．０μｍ以上６．０μｍ以下である、亜鉛箔を提供するものである。 The present invention provides a zinc foil having an arithmetic mean roughness Ra of 1.0 μm or more and 6.0 μm or less on at least one surface measured according to JIS B0601-2001.
また本発明は、ＪＩＳ Ｂ０６０１－２００１に準拠して測定された最大高さＲｚが、少なくとも一方の面において６．０μｍ以上３５．０μｍ以下である、亜鉛箔を提供するものである。 The present invention also provides a zinc foil having a maximum height Rz of 6.0 μm or more and 35.0 μm or less on at least one surface as measured according to JIS B0601-2001.
また本発明は、亜鉛源を含む電解液を用い、該電解液に浸漬されたカソードに、亜鉛を還元析出させる亜鉛箔の製造方法であって、
前記電解液として、亜鉛の濃度が１ｇ／Ｌ以上５０ｇ／Ｌ未満である電解液を用い、
前記電解液を循環速度０．００１Ｌ／（ｍｉｎ・ｍｍ２）以上１Ｌ／（ｍｉｎ・ｍｍ２）以下の範囲で循環させながら還元を行い、
還元を行うときの電流密度を３０００Ａ／ｍ２より大きく１００００Ａ／ｍ２以下に設定する、亜鉛箔の製造方法を提供するものである。
The present invention also provides a method for producing a zinc foil by reducing and depositing zinc on a cathode immersed in the electrolytic solution using an electrolytic solution containing a zinc source,
As the electrolytic solution, using an electrolytic solution having a zinc concentration of 1 g / L or more and less than 50 g / L,
Reduction is performed while the electrolytic solution is circulated at a circulation rate of 0.001 L/(min·mm 2 ) or more and 1 L/(min·mm 2 ) or less,
Provided is a method for producing a zinc foil, wherein the current density during reduction is set at more than 3000 A/m 2 and not more than 10000 A/m 2 .
本発明によれば、高レートで放電した場合であっても電圧の低下が抑制された電池を実現し得る亜鉛箔が提供される。 ADVANTAGE OF THE INVENTION According to this invention, the zinc foil which can implement|achieve the battery by which the fall of the voltage was suppressed even when discharging at a high rate is provided.
以下本発明を、その好ましい実施形態に基づき説明する。本発明の亜鉛箔は、亜鉛を母材とするものである。「亜鉛を母材とする」とは、亜鉛箔のうち、亜鉛元素が好ましくは８０質量％以上の含有率を占めることをいう。亜鉛元素の含有割合は、ＩＣＰ発光分光分析により測定することができる。 The present invention will be described below based on its preferred embodiments. The zinc foil of the present invention uses zinc as a base material. The term "zinc as the base material" means that zinc element preferably accounts for 80% by mass or more of the zinc foil. The zinc element content can be measured by ICP emission spectrometry.
本発明の亜鉛箔は、従来知られている亜鉛箔に比べて、表面が粗いことを特徴の一つとしている。このことによって、本発明の亜鉛箔を電極材料、特に負極材料として用いた電池は、従来の亜鉛箔を電極材料として用いた電池に比べて、高レートで放電した場合であっても電池の電圧の低下が抑制される。この理由は完全に明らかではないが、亜鉛箔の表面が粗く、凹凸があることで、単位面積当たりの表面積が高くなり、反応面積が増えることで放電時の電流密度が低下するためではないかと本発明者は考えている。この利点を一層顕著なものとする観点から、亜鉛箔の表面粗さは、少なくとも一方の面において、ＪＩＳＢ０６０１－２００１に準拠して測定された算術平均粗さＲａで表して、１．０μｍ以上であることが好ましく、１.３μｍ以上であることが更に好ましく、１．５μｍ以上であることが一層好ましい。算術平均粗さＲａの上限値に特に制限はないが、６．０μｍ程度に、特に５．５μｍ程度に表面が粗ければ、高レートで放電した場合であっても電池の電圧の低下が抑制される。算術平均粗さＲａを望ましい値にするための亜鉛箔の好適な製造方法については後述する。また、高レートで放電した場合であっても電池の電圧の低下を更に一層抑制する観点から、亜鉛箔の表面粗さが前記の範囲である面が、電池の正極に対向するように配置されていることが好ましい。 One of the characteristics of the zinc foil of the present invention is that it has a rougher surface than conventionally known zinc foils. As a result, the battery using the zinc foil of the present invention as an electrode material, particularly as a negative electrode material, can maintain the battery voltage even when discharged at a high rate compared to a battery using a conventional zinc foil as an electrode material. decrease in The reason for this is not completely clear, but it is thought that the surface area of the zinc foil is rough and uneven, which increases the surface area per unit area and increases the reaction area, which reduces the current density during discharge. The inventor thinks. From the viewpoint of making this advantage even more remarkable, the surface roughness of the zinc foil is 1.0 μm or more, expressed as an arithmetic mean roughness Ra measured in accordance with JISB0601-2001, on at least one surface. It is preferably 1.3 μm or more, more preferably 1.5 μm or more. The upper limit of the arithmetic mean roughness Ra is not particularly limited, but if the surface is rough to about 6.0 μm, especially about 5.5 μm, the voltage drop of the battery is suppressed even when discharged at a high rate. be done. A preferred method of manufacturing a zinc foil for making the arithmetic mean roughness Ra a desirable value will be described later. In addition, from the viewpoint of further suppressing the voltage drop of the battery even when discharged at a high rate, the surface of the zinc foil having the surface roughness within the above range is arranged so as to face the positive electrode of the battery. preferably.
これまで知られている亜鉛箔は、一般に圧延法又は電解法で製造されていた。圧延法で製造された亜鉛箔は、表面粗さが低く平滑なものになっている。電解法で製造された亜鉛箔も同様である。このように、従来知られている亜鉛箔はその表面が平滑であり、その平滑さを保ったまま使用されていた。このような従来技術に対して本発明者は、亜鉛箔の表面を敢えて粗くすることで、意外にも、電池を高レートで放電した場合であっても電圧の低下が抑制されることを知見し、本発明の完成に至った。 Zinc foils known so far have generally been produced by a rolling method or an electrolytic method. A zinc foil produced by a rolling method has a low surface roughness and is smooth. The same applies to zinc foil produced by the electrolytic method. Thus, the conventionally known zinc foil has a smooth surface and has been used while maintaining the smoothness. Contrary to such prior art, the present inventors unexpectedly discovered that by intentionally roughening the surface of the zinc foil, the voltage drop can be suppressed even when the battery is discharged at a high rate. As a result, the present invention has been completed.
亜鉛箔の表面の粗さに関しては、高レートで放電した場合であっても電池の電圧の低下を一層抑制する観点から、上述した算術平均粗さＲａに加え、ＪＩＳＢ０６０１－２００１に準拠して測定された最大高さＲｚが６．０μｍ以上であることが好ましく、８．０μｍ以上であることが更に好ましく、１０．０μｍ以上であることが一層好ましい。最大高さＲｚの上限値に特に制限はないが、３５．０μｍ程度、特に２０．０μｍ程度に表面が粗ければ、電池を高レートで放電した場合であっても電圧の低下が一層抑制される。最大高さＲｚを望ましい値にするための亜鉛箔の好適な製造方法については後述する。高レートで放電した場合であっても電池の電圧の低下を更に一層抑制する観点から、亜鉛箔の最大高さＲｚが前記の範囲である面が、電池の正極に対向するように配置されていることが好ましい。 Regarding the surface roughness of the zinc foil, from the viewpoint of further suppressing the voltage drop of the battery even when discharged at a high rate, in addition to the arithmetic average roughness Ra described above, it is measured in accordance with JISB0601-2001. The maximum height Rz is preferably 6.0 μm or more, more preferably 8.0 μm or more, and even more preferably 10.0 μm or more. The upper limit of the maximum height Rz is not particularly limited, but if the surface is rough to about 35.0 μm, especially about 20.0 μm, the voltage drop is further suppressed even when the battery is discharged at a high rate. be. A preferred method of manufacturing the zinc foil for setting the maximum height Rz to a desired value will be described later. From the viewpoint of further suppressing the voltage drop of the battery even when discharged at a high rate, the surface of the zinc foil having the maximum height Rz within the above range is arranged so as to face the positive electrode of the battery. preferably.
本発明の亜鉛箔は、上述のとおり亜鉛を母材とするものであるところ、亜鉛以外の金属元素を含んでいてもよい。それによって、電池を高レートで放電した場合であっても電圧の低下が抑制されるという効果が奏されることに加えて、電池の保存中のガス発生が抑制されるという効果も奏される。この観点から、金属元素として、水素過電圧が亜鉛よりも高いか又は酸化還元電位が亜鉛よりも貴であるものを用いることが有利である。そのような金属元素としては、ビスマス、インジウム、マグネシウム、カルシウム、ガリウム、スズ、バリウム、ストロンチウム、銀及びマンガンからなる群より選択される少なくとも一種が挙げられる。これらの金属元素のうち、ビスマス、インジウム、スズ、銀、ガリウムからなる群より選択される少なくとも一種を用いることが、ガス発生が更に抑制される点から好ましく、ビスマス、インジウム、スズ及び銀からなる群より選択される少なくとも一種を用いることが、ガス発生の一層の抑制の点から好ましい。 As described above, the zinc foil of the present invention uses zinc as a base material, but may contain metal elements other than zinc. As a result, even when the battery is discharged at a high rate, the voltage drop is suppressed, and in addition, the gas generation during storage of the battery is suppressed. . From this point of view, it is advantageous to use a metal element that has a higher hydrogen overvoltage than zinc or a nobler oxidation-reduction potential than zinc. Such metal elements include at least one selected from the group consisting of bismuth, indium, magnesium, calcium, gallium, tin, barium, strontium, silver and manganese. Among these metal elements, it is preferable to use at least one selected from the group consisting of bismuth, indium, tin, silver, and gallium from the viewpoint of further suppressing gas generation. It is preferable to use at least one selected from the group from the viewpoint of further suppression of gas generation.
電池の保存中のガス発生を効果的に抑制する観点から、亜鉛箔における金属元素の含有割合は、金属元素の合計量で表して、質量基準で１０ｐｐｍ以上１００００ｐｐｍ以下であることが好ましく、１５ｐｐｍ以上８０００ｐｐｍ以下であることが更に好ましく、質量基準で２０ｐｐｍ以上７０００ｐｐｍ以下であることが一層好ましく、３０ｐｐｍ以上６５００ｐｐｍ以下であることが更に一層好ましく、特に４０ｐｐｍ以上６０００ｐｐｍ以下であることが好ましい。亜鉛箔における金属元素の含有割合は、ＩＣＰ発光分光分析法にて測定できる。ＩＣＰ発光分光分析法による測定には、ＪＩＳ Ｈ１１１１に準拠した方法を採用できる。具体的には、塩酸等の酸性溶液に亜鉛箔を溶解させた後、ＩＣＰ発光分光分析法で亜鉛以外の含有金属の濃度を測定し、全金属の溶液濃度を１として各種金属元素の含有割合を質量として換算する。 From the viewpoint of effectively suppressing gas generation during storage of the battery, the content of metal elements in the zinc foil, expressed as the total amount of metal elements, is preferably 10 ppm or more and 10000 ppm or less on a mass basis, and is preferably 15 ppm or more. It is more preferably 8000 ppm or less, more preferably 20 ppm or more and 7000 ppm or less, still more preferably 30 ppm or more and 6500 ppm or less, and particularly preferably 40 ppm or more and 6000 ppm or less. The content of metal elements in the zinc foil can be measured by ICP emission spectrometry. A method conforming to JIS H1111 can be used for measurement by ICP emission spectrometry. Specifically, after dissolving zinc foil in an acidic solution such as hydrochloric acid, the concentration of contained metals other than zinc is measured by ICP emission spectrometry, and the concentration of all metals in the solution is set to 1, and the content ratio of various metal elements. is converted as mass.
亜鉛箔中において前記の金属元素の存在状態は明らかでないが、少なくとも亜鉛との固溶体の状態ではない。固溶体の状態とは金属元素の添加によって亜鉛の結晶構造が変化する状態のことである。金属元素を含有する亜鉛箔の断面を、走査型電子顕微鏡によるエネルギー分散型Ｘ線分光法（特性Ｘ線検出法）を用いて元素マッピングすると、亜鉛の金属単体としての存在状態のマッピング像と、ビスマスを始めとする各種金属元素の金属単体としての存在状態のマッピング像とがそれぞれ得られる。 Although the state of existence of the metal element in the zinc foil is not clear, at least it is not in the state of a solid solution with zinc. The state of solid solution is a state in which the crystal structure of zinc changes due to the addition of metal elements. Element mapping of a cross section of a zinc foil containing a metal element using energy dispersive X-ray spectroscopy (characteristic X-ray detection method) using a scanning electron microscope yields a mapping image of the state of existence of zinc as a single metal, A mapping image of the state of existence of various metal elements including bismuth as an elemental metal is obtained.
前記の各種金属元素のうち、特にビスマスが亜鉛箔中に含まれていると、電池の保存中のガス発生が一層効果的に抑制されるので好ましい。電池の保存中のガス発生を更に一層抑制するために、亜鉛箔におけるビスマスの含有割合は質量基準で１０ｐｐｍ以上１００００ｐｐｍ以下であることが好ましく、１５ｐｐｍ以上８０００ｐｐｍ以下であることが更に好ましく、２０ｐｐｍ以上６０００ｐｐｍ以下であることが一層好ましく、３０ｐｐｍ以上３０００ｐｐｍ以下であることが更に一層好ましく、特に４０ｐｐｍ以上１２００ｐｐｍ以下であることが好ましく、とりわけ４００ｐｐｍ以上７００ｐｐｍ以下であることが好ましい。この場合、亜鉛箔は残部が亜鉛及び不可避不純物からなる。 Among the various metal elements mentioned above, bismuth, in particular, is preferably contained in the zinc foil because it more effectively suppresses gas generation during storage of the battery. In order to further suppress gas generation during storage of the battery, the content of bismuth in the zinc foil is preferably 10 ppm or more and 10000 ppm or less, more preferably 15 ppm or more and 8000 ppm or less, and 20 ppm or more and 6000 ppm or less. It is more preferably 30 ppm or more and 3000 ppm or less, even more preferably 40 ppm or more and 1200 ppm or less, and most preferably 400 ppm or more and 700 ppm or less. In this case, the balance of the zinc foil is zinc and unavoidable impurities.
本発明の亜鉛箔は、一次電池及び二次電池において不働態化等の悪影響を低減する観点からアルミニウムを非含有であることが望ましい。また、環境負荷を軽減させる観点から鉛を非含有であることが望ましい。また本発明の亜鉛箔が、これらの元素のうちの両者又は一方を含有したとしても、それらの元素の含有割合は極力低いことが望ましい。
具体的には、アルミニウムについてはその含有割合が０．０４質量％以下であることが好ましく、０．０３質量％以下であることが更に好ましく、０．０２質量％以下であることが一層好ましい。
鉛についてはその含有割合が質量基準で６０ｐｐｍ以下であることが好ましく、５０ｐｐｍ以下であることが更に好ましく、４０ｐｐｍ以下であることが一層好ましい。
本発明の亜鉛箔に含まれるアルミニウム及び鉛の含有割合は、ＩＣＰ発光分光分析法によって測定される。
また、本発明の亜鉛箔は、カドミウムを非含有であるか、又は含有したとしてもその割合は極力低いことが望ましい。特にカドミウムの含有割合は質量基準で１０ｐｐｍ以下であることが望ましい。
The zinc foil of the present invention preferably does not contain aluminum from the viewpoint of reducing adverse effects such as passivation in primary and secondary batteries. In addition, it is desirable that lead is not contained from the viewpoint of reducing the environmental load. Even if the zinc foil of the present invention contains both or one of these elements, it is desirable that the content of these elements is as low as possible.
Specifically, the aluminum content is preferably 0.04% by mass or less, more preferably 0.03% by mass or less, and even more preferably 0.02% by mass or less.
The content of lead is preferably 60 ppm or less, more preferably 50 ppm or less, and even more preferably 40 ppm or less on a mass basis.
The contents of aluminum and lead contained in the zinc foil of the present invention are measured by ICP emission spectrometry.
Moreover, it is desirable that the zinc foil of the present invention does not contain cadmium, or even if it does contain cadmium, its proportion is as low as possible. In particular, the content of cadmium is desirably 10 ppm or less on a mass basis.
次に、本発明の亜鉛箔の好適な製造方法について説明する。本発明の亜鉛箔は好適には電解法によって製造される、いわゆる電解箔である。電解法においては、亜鉛源を含む電解液にアノード及びカソードを浸漬させ、カソードに亜鉛箔を析出させる。亜鉛源を含む電解液としては、硫酸亜鉛水溶液、硝酸亜鉛水溶液、塩化亜鉛水溶液等が挙げられる。電解液に含まれる亜鉛の濃度は、得られる亜鉛箔の表面粗さに影響を及ぼすことが本発明者の検討の結果判明した。詳細には、電解液に含まれる亜鉛の濃度を比較的低めに設定することが、表面が粗い亜鉛箔を製造する観点から有利である。具体的には電解液として、亜鉛の濃度が好ましくは１ｇ／Ｌ以上５０ｇ／Ｌ未満、更に好ましくは２ｇ／Ｌ以上４０ｇ／Ｌ以下、一層好ましくは３ｇ／Ｌ以上３０ｇ／Ｌ以下、更に一層好ましくは１１ｇ／Ｌ以上２８ｇ／Ｌ以下であるものを用いることが有利である。 Next, a preferred method for producing the zinc foil of the present invention will be described. The zinc foil of the present invention is preferably a so-called electrolytic foil produced by an electrolytic method. In the electrolysis method, the anode and cathode are immersed in an electrolytic solution containing a zinc source, and a zinc foil is deposited on the cathode. Electrolytic solutions containing a zinc source include an aqueous zinc sulfate solution, an aqueous zinc nitrate solution, an aqueous zinc chloride solution, and the like. As a result of investigations by the present inventors, it was found that the concentration of zinc contained in the electrolytic solution affects the surface roughness of the resulting zinc foil. Specifically, setting the concentration of zinc contained in the electrolytic solution to a relatively low value is advantageous from the viewpoint of producing a zinc foil with a rough surface. Specifically, the electrolytic solution has a zinc concentration of preferably 1 g/L or more and less than 50 g/L, more preferably 2 g/L or more and 40 g/L or less, still more preferably 3 g/L or more and 30 g/L or less, and even more preferably is 11 g/L or more and 28 g/L or less.
電解を行うときの電流密度も、得られる亜鉛箔の表面粗さに影響を及ぼすことが本発明者の検討の結果判明した。詳細には、電解を行うときの電流密度を比較的高めに設定することが、表面が粗い亜鉛箔を製造する観点から有利である。具体的には電流密度を好ましくは３０００Ａ／ｍ２以上１００００Ａ／ｍ２以下、更に好ましくは３２００Ａ／ｍ２以上９０００Ａ／ｍ２以下、一層好ましくは３４００Ａ／ｍ２以上８０００Ａ／ｍ２以下、更に一層好ましくは３４００Ａ／ｍ２以上６０００Ａ／ｍ２以下に設定することが有利である。 As a result of investigations by the present inventors, it was found that the current density during electrolysis also affects the surface roughness of the resulting zinc foil. Specifically, setting a relatively high current density during electrolysis is advantageous from the viewpoint of producing a zinc foil with a rough surface. Specifically, the current density is preferably 3000 A/m 2 or more and 10000 A/m 2 or less, more preferably 3200 A/m 2 or more and 9000 A/m 2 or less, still more preferably 3400 A/m 2 or more and 8000 A/m 2 or less. It is advantageous to set preferably to 3400 A/m 2 or more and 6000 A/m 2 or less.
電解液に含まれる亜鉛の濃度を低く設定し且つ電解を行うときの電流密度を高く設定することで、表面が粗い亜鉛箔が得られる理由は以下のとおりであると本発明者は考えている。
亜鉛電解析出反応は、亜鉛イオンの還元反応と水素イオンの還元反応との競争反応である。つまりカソードの表面においては、水素ガスの発生を伴いながら亜鉛イオンの還元が生じる。電解液に含まれる亜鉛の濃度が低い場合、亜鉛イオンの拡散律速に起因して相対的に水素イオンの還元反応が優位に生じる。電流密度が高い場合も同様に、水素イオンの還元反応が相対的に優位となる。それらの結果、金属亜鉛の平坦な析出が水素ガスによって阻害され、金属亜鉛は凹凸状に析出し、得られる亜鉛箔の表面が粗くなる。
The present inventor believes that the reason why a zinc foil with a rough surface can be obtained by setting the concentration of zinc contained in the electrolytic solution low and setting the current density at the time of electrolysis high is as follows. .
The zinc electrolytic deposition reaction is a competitive reaction between the reduction reaction of zinc ions and the reduction reaction of hydrogen ions. That is, on the surface of the cathode, reduction of zinc ions occurs with the generation of hydrogen gas. When the concentration of zinc contained in the electrolytic solution is low, the reduction reaction of hydrogen ions relatively dominates due to diffusion rate control of zinc ions. Similarly, when the current density is high, the reduction reaction of hydrogen ions is relatively dominant. As a result, the flat deposition of metallic zinc is inhibited by the hydrogen gas, metallic zinc is deposited unevenly, and the resulting zinc foil has a rough surface.
上述した電解条件（亜鉛の濃度及び電流密度）を採用することに加え、目的とする表面粗さを有する亜鉛箔を首尾よく得る観点から、電解を行っている間、電解液を循環させることが有利であることが本発明者の検討の結果判明した。電解液を循環させるためには、例えば電解装置として、閉じた流路と、該流路中に配置された電解槽と、該流路中に配置されたポンプとを備えたものを用い、ポンプを駆動させて電解液を一方向に向けて電解槽中を流通させればよい。電解に使用するアノード及びカソードは、電解槽内に、両者を対向させた状態で浸漬させればよい。アノード及びカソードは、それらの対向面（カソードで言えば電着面）が、電解液の流通方向と平行になるように電解槽中に配置されることが好ましい。 In addition to adopting the electrolysis conditions (zinc concentration and current density) described above, from the viewpoint of successfully obtaining a zinc foil having the desired surface roughness, it is recommended to circulate the electrolyte during electrolysis. As a result of investigations by the inventors, it was found to be advantageous. In order to circulate the electrolytic solution, for example, an electrolytic device comprising a closed flow path, an electrolytic cell arranged in the flow path, and a pump arranged in the flow path is used. is driven to circulate the electrolytic solution in one direction in the electrolytic cell. The anode and cathode used for electrolysis may be immersed in an electrolytic bath while facing each other. The anode and cathode are preferably arranged in the electrolytic cell such that their facing surfaces (electrodeposition surfaces in the case of the cathode) are parallel to the flow direction of the electrolytic solution.
電解液を循環させつつ電解を行うときには、電解液の流速、すなわち循環速度を比較的低めに設定することが、表面が粗い亜鉛箔を製造する観点から有利である。詳細には、電解液の循環速度を０．００１Ｌ／（ｍｉｎ・ｍｍ２）以上１Ｌ／（ｍｉｎ・ｍｍ２）以下に設定することが好ましく、０．００２Ｌ／（ｍｉｎ・ｍｍ２）以上０．６Ｌ／（ｍｉｎ・ｍｍ２）以下に設定することが更に好ましく、０．００３Ｌ／（ｍｉｎ・ｍｍ２）以上０．４Ｌ／（ｍｉｎ・ｍｍ２）以下に設定することが一層好ましく、０．００５Ｌ／（ｍｉｎ・ｍｍ２）以上０．０４Ｌ／（ｍｉｎ・ｍｍ２）以下に設定することが更に一層好ましく、０．０１１Ｌ／（ｍｉｎ・ｍｍ２）以上０．０３２Ｌ／（ｍｉｎ・ｍｍ２）以下に設定することが更に一層好ましい。循環速度は、電解液の流量（Ｌ／ｍｉｎ）を、電極間面積（ｍｍ２）で除すことで算出される。電極間面積は、図１に示すとおり、電極間距離（ｍｍ）と、電着電極幅（ｍｍ）との積で表される。図１においては、紙面と直交する方向に向けて電解液を流通させることが好ましい。また図１においては、紙面と直交する方向に沿って電極が延在している。 When performing electrolysis while circulating the electrolytic solution, setting the flow rate of the electrolytic solution, that is, the circulation speed, to be relatively low is advantageous from the viewpoint of producing a zinc foil with a rough surface. Specifically, the circulation speed of the electrolytic solution is preferably set to 0.001 L/(min·mm 2 ) or more and 1 L/(min·mm 2 ) or less, and 0.002 L/(min·mm 2 ) or more to 0.002 L/(min·mm 2 ) or more. It is more preferably set to 6 L/(min-mm 2 ) or less, more preferably 0.003 L/(min-mm 2 ) or more and 0.4 L/(min-mm 2 ) or less, and 0.005 L /(min·mm 2 ) or more and 0.04 L/(min·mm 2 ) or less is even more preferable, and 0.011 L/(min·mm 2 ) or more and 0.032 L/(min·mm 2 ) or less is even more preferable. The circulation speed is calculated by dividing the flow rate (L/min) of the electrolytic solution by the inter-electrode area (mm 2 ). The inter-electrode area is represented by the product of the inter-electrode distance (mm) and the electrodeposition electrode width (mm), as shown in FIG. In FIG. 1, it is preferable to flow the electrolytic solution in a direction perpendicular to the plane of the paper. Also, in FIG. 1, the electrodes extend in a direction perpendicular to the plane of the paper.
電解に使用するアノードとしては、公知の寸法安定化電極（ＤＳＥ）を用いることが好ましい。ＤＳＥとしては、例えば酸化イリジウムをコートしたチタン電極、酸化ルテニウムをコートしたチタン電極などが好適に用いられる。一方、カソードとしては、その種類に特に制限はなく、亜鉛の還元に影響を及ぼさない材料が適宜選択される。例えばアルミニウムを用いることができる。 As the anode used for electrolysis, it is preferable to use a known dimensionally stabilized electrode (DSE). As the DSE, for example, a titanium electrode coated with iridium oxide, a titanium electrode coated with ruthenium oxide, or the like is preferably used. On the other hand, the type of the cathode is not particularly limited, and a material that does not affect the reduction of zinc is appropriately selected. For example aluminum can be used.
電解液は、必要に応じ、亜鉛源に加えて、上述した金属元素源も含有する。電解液に含まれる金属元素源の濃度は、電解液中の亜鉛と金属元素との合計質量に対して、金属元素の質量の割合が好ましくは１０ｐｐｍ以上１００００ｐｐｍ以下であることが好ましく、１５ｐｐｍ以上８０００ｐｐｍ以下であることが更に好ましく、２０ｐｐｍ以上７０００ｐｐｍ以下であることが一層好ましく、３０ｐｐｍ以上６５００ｐｐｍ以下であることが更に一層好ましく、特に３０ｐｐｍ以上６０００ｐｐｍ以下であることが好ましく、とりわけ４００ｐｐｍ以上６０００ｐｐｍ以下であることが好ましい。 The electrolytic solution also contains the aforementioned metal element source in addition to the zinc source, if necessary. Regarding the concentration of the metal element source contained in the electrolyte, the ratio of the mass of the metal element to the total mass of zinc and the metal element in the electrolyte is preferably 10 ppm or more and 10000 ppm or less, preferably 15 ppm or more and 8000 ppm. It is more preferably 20 ppm or more and 7000 ppm or less, even more preferably 30 ppm or more and 6500 ppm or less, particularly preferably 30 ppm or more and 6000 ppm or less, especially 400 ppm or more and 6000 ppm or less. is preferred.
電解液は、更に、他の化合物を含んでいてもよい。他の化合物としては、例えば電解液のｐＨを調整する目的で硫酸を添加することができる。 The electrolytic solution may further contain other compounds. As another compound, for example, sulfuric acid can be added for the purpose of adjusting the pH of the electrolytic solution.
電解液は非加熱状態又は加熱状態で電解に供することができる。電解液を加熱した状態で電解を行う場合には、電解液の温度を好ましくは１０℃以上９０℃以下に設定する。電解液の温度は、より好ましくは１２℃以上９０℃以下であり、更に好ましくは１５℃以上８０℃以下であり、より更に好ましくは２０℃以上７０℃以下である。 The electrolytic solution can be subjected to electrolysis in a non-heated state or a heated state. When performing electrolysis with the electrolytic solution heated, the temperature of the electrolytic solution is preferably set to 10° C. or higher and 90° C. or lower. The temperature of the electrolytic solution is more preferably 12° C. or higher and 90° C. or lower, still more preferably 15° C. or higher and 80° C. or lower, and even more preferably 20° C. or higher and 70° C. or lower.
以上の条件で電解を行い、電解液に浸漬されたカソードに亜鉛を還元析出させ、目的とする亜鉛箔を得る。電解は、亜鉛箔の厚みが目的とする値となるまで行う。このようにして得られた亜鉛箔は、電解液に対向する面（以下、便宜的に「Ｍ面」という。）の表面粗さが上述した範囲内となる。陰極に対向する面（以下、便宜的に「Ｓ面」という。）は、Ｍ面よりも平滑なものとなる。 Electrolysis is performed under the above conditions, zinc is reduced and deposited on the cathode immersed in the electrolytic solution, and the desired zinc foil is obtained. Electrolysis is performed until the thickness of the zinc foil reaches a target value. In the zinc foil thus obtained, the surface roughness of the surface facing the electrolytic solution (hereinafter referred to as "M surface" for convenience) is within the range described above. The surface facing the cathode (hereinafter referred to as "S surface" for convenience) is smoother than the M surface.
このようにして得られた本発明の亜鉛箔は、例えば一次電池及び二次電池の電池用負極活物質材料として好適に用いられる。一次電池としては例えばマンガン電池が挙げられる。二次電池としては例えばニッケル・亜鉛電池、空気・亜鉛電池及びマンガン・亜鉛電池が挙げられる。更に、亜鉛箔自体が導電性を有することから、該亜鉛箔は集電体としても機能する。これによって、集電体を用いることなく、亜鉛箔そのものを負極として用いることも可能である。 The zinc foil of the present invention thus obtained is suitably used, for example, as a negative electrode active material for primary batteries and secondary batteries. Examples of primary batteries include manganese batteries. Examples of secondary batteries include nickel-zinc batteries, air-zinc batteries and manganese-zinc batteries. Furthermore, since the zinc foil itself has electrical conductivity, the zinc foil also functions as a current collector. This makes it possible to use the zinc foil itself as the negative electrode without using a current collector.
本発明は更に以下の亜鉛箔を開示する。
［１］
ＪＩＳ Ｂ０６０１－２００１に準拠して測定された算術平均粗さＲａが、少なくとも一方の面において１．０μｍ以上６．０μｍ以下である、亜鉛箔。
［２］
ＪＩＳ Ｂ０６０１－２００１に準拠して測定された最大高さＲｚが、少なくとも一方の面において６．０μｍ以上３５．０μｍ以下である、亜鉛箔。
［３］
ビスマスを更に含む、［１］又は［２］に記載の亜鉛箔。
［４］
電解箔である、［１］ないし［３］のいずれか一に記載の亜鉛箔。
［５］
［１］ないし［４］のいずれか一に記載の亜鉛箔を備えた、電池の負極材料。
The present invention further discloses the following zinc foil.
[1]
A zinc foil having an arithmetic mean roughness Ra measured in accordance with JIS B0601-2001 of 1.0 μm or more and 6.0 μm or less on at least one surface.
[2]
A zinc foil having a maximum height Rz of 6.0 μm or more and 35.0 μm or less on at least one surface as measured according to JIS B0601-2001.
[3]
The zinc foil according to [1] or [2], further comprising bismuth.
[4]
The zinc foil according to any one of [1] to [3], which is an electrolytic foil.
[5]
A negative electrode material for a battery comprising the zinc foil according to any one of [1] to [4].
［６］
［１］ないし［４］のいずれか一に記載の亜鉛箔を負極に備え、
前記亜鉛箔は、該亜鉛箔の面のうち、前記算術平均粗さＲａが１．０μｍ以上６．０μｍ以下である面、又は前記最大高さＲｚが６．０μｍ以上３５．０μｍ以下である面が、正極に対向するように配置されている、電池。
［７］
亜鉛源を含む電解液を用い、該電解液に浸漬されたカソードに、亜鉛を還元析出させる亜鉛箔の製造方法であって、
前記電解液として、亜鉛の濃度が１ｇ／Ｌ以上５０ｇ／Ｌ未満である電解液を用い、
前記電解液を循環速度０．００１Ｌ／（ｍｉｎ・ｍｍ２）以上１Ｌ／（ｍｉｎ・ｍｍ２）以下の範囲で循環させながら還元を行い、
還元を行うときの電流密度を３０００Ａ／ｍ２より大きく１００００Ａ／ｍ２以下に設定する、亜鉛箔の製造方法。
[6]
The zinc foil according to any one of [1] to [4] is provided on the negative electrode,
Among the surfaces of the zinc foil, the surface having the arithmetic mean roughness Ra of 1.0 μm or more and 6.0 μm or less, or the surface having the maximum height Rz of 6.0 μm or more and 35.0 μm or less is positioned opposite the positive electrode.
[7]
A method for producing a zinc foil by reducing and depositing zinc on a cathode immersed in the electrolytic solution using an electrolytic solution containing a zinc source,
As the electrolytic solution, using an electrolytic solution having a zinc concentration of 1 g / L or more and less than 50 g / L,
Reduction is performed while the electrolytic solution is circulated at a circulation rate of 0.001 L/(min·mm 2 ) or more and 1 L/(min·mm 2 ) or less,
A method for producing a zinc foil, wherein the current density during reduction is set to more than 3000 A/m 2 and 10000 A/m 2 or less.
以下、実施例により本発明を更に詳細に説明する。しかしながら本発明の範囲は、かかる実施例に制限されない。特に断らない限り、「％」は「質量％」を意味する。 EXAMPLES The present invention will be described in more detail below with reference to examples. However, the scope of the invention is not limited to such examples. "%" means "% by mass" unless otherwise specified.
〔実施例１〕
（１）電解液の調製
亜鉛化合物として酸化亜鉛を用いた。これを硫酸ととともに水に溶解して電解液を調製した。電解液における亜鉛の濃度は２５ｇ／Ｌとした。硫酸の濃度は硫酸イオンの総量をＨ２ＳＯ４として換算した値として２００ｇ／Ｌとした。電解液に硝酸ビスマスを添加した。ビスマスの濃度は、目的とする亜鉛箔に含まれるビスマスの含有割合が表１に示す値となるように調整した。
[Example 1]
(1) Preparation of electrolytic solution Zinc oxide was used as a zinc compound. This was dissolved in water together with sulfuric acid to prepare an electrolytic solution. The concentration of zinc in the electrolytic solution was 25 g/L. The concentration of sulfuric acid was 200 g/L as a value converted from the total amount of sulfate ions as H 2 SO 4 . Bismuth nitrate was added to the electrolyte. The concentration of bismuth was adjusted so that the content of bismuth contained in the target zinc foil was the value shown in Table 1.
（２）亜鉛の還元析出
アノードとして、酸化イリジウムをコートしたチタン電極からなるＤＳＥを用いた。カソードとしてアルミニウム板を用いた。アノード及びカソードを図１に示す配置状態とし、電解液を３５℃に加熱した状態下にアノードとカソードとの間に電流を流した。電流密度は３５００Ａ／ｍ２とした。電解液は、循環速度を０．０２９Ｌ／（ｍｉｎ・ｍｍ２）に設定して循環させた。この条件で電解を行い、厚み７０μｍ、単位面積当たりの重量３５ｍｇ／ｃｍ２の亜鉛箔を得た。得た亜鉛箔は、イオン交換水で洗浄し、熱風で乾燥させた。
(2) Reductive Deposition of Zinc A DSE consisting of a titanium electrode coated with iridium oxide was used as an anode. An aluminum plate was used as the cathode. The anode and cathode were arranged as shown in FIG. 1, and an electric current was passed between the anode and the cathode while the electrolytic solution was heated to 35.degree. The current density was 3500 A/m 2 . The electrolytic solution was circulated at a circulation rate of 0.029 L/(min·mm 2 ). Electrolysis was performed under these conditions to obtain a zinc foil having a thickness of 70 μm and a weight per unit area of 35 mg/cm 2 . The obtained zinc foil was washed with deionized water and dried with hot air.
〔実施例２〕
実施例１において、電解を行うときの電流密度を、表１に示す値とした。これ以外は実施例１と同様にして厚み１３０μｍ、単位面積当たりの重量３４ｍｇ／ｃｍ２の亜鉛箔を得た。
[Example 2]
In Example 1, the values shown in Table 1 were used as the current densities for the electrolysis. A zinc foil having a thickness of 130 μm and a weight per unit area of 34 mg/cm 2 was obtained in the same manner as in Example 1 except for this.
〔実施例３〕
実施例１で用いた電解液において、亜鉛濃度を表１に示す値とした。ビスマスの濃度は、目的とする亜鉛箔に含まれるビスマスの含有割合が表１に示す値となるように調整した。また、電解を行うときの電流密度を、同表に示す値とした。これら以外は実施例１と同様にして厚み１４０μｍ、単位面積当たりの重量３６ｍｇ／ｃｍ２の亜鉛箔を得た。
[Example 3]
In the electrolytic solution used in Example 1, the zinc concentration was set to the value shown in Table 1. The concentration of bismuth was adjusted so that the content of bismuth contained in the target zinc foil was the value shown in Table 1. In addition, the current density when performing electrolysis was set to the value shown in the same table. A zinc foil having a thickness of 140 μm and a weight per unit area of 36 mg/cm 2 was obtained in the same manner as in Example 1 except for the above.
〔実施例４〕
実施例１で用いた電解液において、亜鉛濃度を表１に示す値とした。ビスマスの濃度は、目的とする亜鉛箔に含まれるビスマスの含有割合が表１に示す値となるように調整した。また、電解を行うときの電流密度を、同表に示す値とした。これら以外は実施例１と同様にして厚み９６μｍ、単位面積当たりの重量３６ｍｇ／ｃｍ２の亜鉛箔を得た。
[Example 4]
In the electrolytic solution used in Example 1, the zinc concentration was set to the value shown in Table 1. The concentration of bismuth was adjusted so that the content of bismuth contained in the target zinc foil was the value shown in Table 1. In addition, the current density when performing electrolysis was set to the value shown in the same table. A zinc foil having a thickness of 96 μm and a weight per unit area of 36 mg/cm 2 was obtained in the same manner as in Example 1 except for the above.
〔比較例１〕
実施例１で用いた電解液において、亜鉛濃度を表１に示す値とした。ビスマスの濃度は、目的とする亜鉛箔に含まれるビスマスの含有割合が表１に示す値となるように調整した。また、電解を行うときの電流密度を、同表に示す値とした。これら以外は実施例１と同様にして厚み５５μｍ、単位面積当たりの重量３４ｍｇ／ｃｍ２の亜鉛箔を得た。
[Comparative Example 1]
In the electrolytic solution used in Example 1, the zinc concentration was set to the value shown in Table 1. The concentration of bismuth was adjusted so that the content of bismuth contained in the target zinc foil was the value shown in Table 1. In addition, the current density when performing electrolysis was set to the value shown in the same table. A zinc foil having a thickness of 55 μm and a weight per unit area of 34 mg/cm 2 was obtained in the same manner as in Example 1 except for the above.
〔比較例２〕
本比較例は比較例１と同じ亜鉛箔である。ただし、後述する評価２及び評価３において、電池を作製するときに正極と対向する面としてＳ面を用いた。
[Comparative Example 2]
This comparative example is the same zinc foil as the first comparative example. However, in Evaluation 2 and Evaluation 3 described later, the S surface was used as the surface facing the positive electrode when the battery was produced.
〔評価１〕
実施例及び比較例で得られた亜鉛箔について、亜鉛を除く各元素の含有割合を上述の方法で測定した。また、亜鉛箔のＭ面の算術平均粗さＲａ及び最大高さＲｚを、ＪＩＳＢ０６０１－２００１に準拠して測定した。ただし、比較例２については、比較例１の亜鉛箔におけるＳ面の表面粗さを測定した。それらの結果を表１に示す。
[Evaluation 1]
Regarding the zinc foils obtained in Examples and Comparative Examples, the content ratio of each element except zinc was measured by the method described above. Also, the arithmetic mean roughness Ra and the maximum height Rz of the M surface of the zinc foil were measured according to JISB0601-2001. However, for Comparative Example 2, the surface roughness of the S surface of the zinc foil of Comparative Example 1 was measured. Those results are shown in Table 1.
〔評価２〕
実施例及び比較例で得られた亜鉛箔を用いて亜鉛負極電池を作製した。
亜鉛箔は正極と対面する面を、露出領域が１ｃｍ×１ｃｍの正方形になるようにマスキングテープで被覆し、露出領域を電極として用いた。亜鉛箔の周囲及び正極と対面しない面もマスキングテープで被覆した。正極に発泡Ｎｉメタルを、参照電極に銀／塩化銀電極を、電解液に酸化亜鉛を飽和させた３１％の水酸化カリウム水溶液を用いた。両極間にポリオレフィン系材料からなる不織布を配置し、電極全域が浸るまでセルに電解液を注いだ。
このようにして作製した電池を室温２０℃で３０分静置した後、電気化学測定装置ＨＺ７０００（北斗電工製）を用いて、放電レートが０．１Ｃ、１Ｃ及び５Ｃであるときの放電電圧ＣＣＶを測定した。その結果を表２に示す。浸漬電位ＯＣＶ及びＣＣＶは、Ａｇ／ＡｇＣｌを基準電極とした負極の電位であり、静置３０分後の電位をＯＣＶとし、放電開始２００秒後の電位をＣＣＶとした。放電レート(電流の大きさ)は、亜鉛箔の露出領域面積（ｃｍ２）と、単位面積当たりの箔重量（ｇ／ｃｍ２）と、亜鉛の理論容量８１９ｍＡｈ／ｇの積とを元にして計算した。
[Evaluation 2]
Zinc anode batteries were produced using the zinc foils obtained in Examples and Comparative Examples.
The surface of the zinc foil facing the positive electrode was covered with a masking tape so that the exposed area was a square of 1 cm×1 cm, and the exposed area was used as an electrode. The circumference of the zinc foil and the surface not facing the positive electrode were also covered with a masking tape. Foamed Ni metal was used as the positive electrode, a silver/silver chloride electrode was used as the reference electrode, and a 31% potassium hydroxide aqueous solution saturated with zinc oxide was used as the electrolyte. A non-woven fabric made of a polyolefin-based material was placed between the two electrodes, and the electrolyte was poured into the cell until the entire electrode was immersed.
After leaving the battery thus prepared at room temperature of 20° C. for 30 minutes, an electrochemical measurement device HZ7000 (manufactured by Hokuto Denko) was used to measure the discharge voltage CCV at discharge rates of 0.1 C, 1 C and 5 C. was measured. Table 2 shows the results. The immersion potentials OCV and CCV are the potentials of the negative electrode with Ag/AgCl as the reference electrode, the potential after 30 minutes of standing was defined as OCV, and the potential after 200 seconds from the start of discharge was defined as CCV. The discharge rate (magnitude of current) was based on the product of the exposed area of the zinc foil (cm 2 ), the foil weight per unit area (g/cm 2 ), and the theoretical zinc capacity of 819 mAh/g. Calculated.
〔評価３〕
電解液として前記の評価２において用いた水酸化カリウム水溶液に代えて、２０％塩化アンモニウム水溶液を用いた。それ以外は評価２と同様にしてニッケル亜鉛電池を作製した。このニッケル亜鉛電池について、評価２と同様にして０．１Ｃ、１Ｃ及び５ＣであるときのＯＣＶ及びＣＣＶを測定した。その結果を表３に示す。
[Evaluation 3]
Instead of the potassium hydroxide aqueous solution used in Evaluation 2, a 20% ammonium chloride aqueous solution was used as the electrolytic solution. A nickel-zinc battery was produced in the same manner as in Evaluation 2 except for the above. For this nickel-zinc battery, OCV and CCV at 0.1C, 1C and 5C were measured in the same manner as in Evaluation 2. Table 3 shows the results.
表１、２及び３に示すとおり、表面が粗い実施例１～４の亜鉛箔を用いた電池は、同実施例よりも表面が平滑である比較例１及び２の亜鉛箔を用いた電池に比べて、高放電レートである５Ｃにおいて、ＯＣＶに対するＣＣＶの低下の度合いが低いことが分かる。つまり、高放電レートでの電池電圧の低下が抑制されていることが分かる。 As shown in Tables 1, 2 and 3, the batteries using the zinc foils of Examples 1 to 4 with rough surfaces were superior to the batteries using the zinc foils of Comparative Examples 1 and 2 having smoother surfaces than the batteries of Examples 1 to 4. In comparison, at 5C, which is a high discharge rate, it can be seen that the degree of decrease in CCV with respect to OCV is low. In other words, it can be seen that the drop in battery voltage at a high discharge rate is suppressed.
Claims (7)
前記亜鉛箔は、該亜鉛箔の面のうち、前記算術平均粗さＲａが１．０μｍ以上６．０μｍ以下である面、又は前記最大高さＲｚが６．０μｍ以上３５．０μｍ以下である面が、正極に対向するように配置されている、電池。 The zinc foil according to claim 1 or 2 is provided in the negative electrode,
Among the surfaces of the zinc foil, the surface having the arithmetic mean roughness Ra of 1.0 μm or more and 6.0 μm or less, or the surface having the maximum height Rz of 6.0 μm or more and 35.0 μm or less is positioned opposite the positive electrode.
前記電解液として、亜鉛の濃度が１ｇ／Ｌ以上５０ｇ／Ｌ未満である電解液を用い、
前記電解液を循環速度０．００１Ｌ／（ｍｉｎ・ｍｍ２）以上１Ｌ／（ｍｉｎ・ｍｍ２）以下の範囲で循環させながら還元を行い、
還元を行うときの電流密度を３０００Ａ／ｍ２より大きく１００００Ａ／ｍ２以下に設定する、亜鉛箔の製造方法。 A method for producing a zinc foil by reducing and depositing zinc on a cathode immersed in the electrolytic solution using an electrolytic solution containing a zinc source,
As the electrolytic solution, using an electrolytic solution having a zinc concentration of 1 g / L or more and less than 50 g / L,
Reduction is performed while the electrolytic solution is circulated at a circulation rate of 0.001 L/(min·mm 2 ) or more and 1 L/(min·mm 2 ) or less,
A method for producing a zinc foil, wherein the current density during reduction is set at more than 3000 A/m 2 and not more than 10000 A/m 2 .
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- 2022-08-01 JP JP2022122909A patent/JP2023044635A/en active Pending
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