JP7422348B2 - Electrode materials for electrochemical devices - Google Patents
Electrode materials for electrochemical devices Download PDFInfo
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- 239000007772 electrode material Substances 0.000 title claims description 42
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 29
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 13
- 229910001122 Mischmetal Inorganic materials 0.000 claims description 8
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 230000000737 periodic effect Effects 0.000 claims description 5
- 229910052684 Cerium Inorganic materials 0.000 claims description 4
- 229910052779 Neodymium Inorganic materials 0.000 claims description 4
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 229910052732 germanium Inorganic materials 0.000 claims description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims description 4
- 229910052745 lead Inorganic materials 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 description 47
- 239000000956 alloy Substances 0.000 description 47
- 238000006722 reduction reaction Methods 0.000 description 20
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 18
- 230000000694 effects Effects 0.000 description 18
- 239000011777 magnesium Substances 0.000 description 16
- 229910052802 copper Inorganic materials 0.000 description 10
- 229910052749 magnesium Inorganic materials 0.000 description 10
- 238000007599 discharging Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 238000009825 accumulation Methods 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 229910052725 zinc Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- 239000008151 electrolyte solution Substances 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000003313 weakening effect Effects 0.000 description 4
- 229910018137 Al-Zn Inorganic materials 0.000 description 3
- 229910018573 Al—Zn Inorganic materials 0.000 description 3
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000003411 electrode reaction Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 229910001425 magnesium ion Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000002161 passivation Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910052706 scandium Inorganic materials 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- 229910001339 C alloy Inorganic materials 0.000 description 2
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000033116 oxidation-reduction process Effects 0.000 description 2
- 229910000882 Ca alloy Inorganic materials 0.000 description 1
- 229910000636 Ce alloy Inorganic materials 0.000 description 1
- 229910001299 Cm alloy Inorganic materials 0.000 description 1
- 229910001202 Cs alloy Inorganic materials 0.000 description 1
- 229910017518 Cu Zn Inorganic materials 0.000 description 1
- 229910017566 Cu-Mn Inorganic materials 0.000 description 1
- 229910017755 Cu-Sn Inorganic materials 0.000 description 1
- 229910017752 Cu-Zn Inorganic materials 0.000 description 1
- 229910017871 Cu—Mn Inorganic materials 0.000 description 1
- 229910017927 Cu—Sn Inorganic materials 0.000 description 1
- 229910017943 Cu—Zn Inorganic materials 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910009378 Zn Ca Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000002482 conductive additive Substances 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006276 transfer reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C23/00—Alloys based on magnesium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C23/00—Alloys based on magnesium
- C22C23/04—Alloys based on magnesium with zinc or cadmium as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C23/00—Alloys based on magnesium
- C22C23/06—Alloys based on magnesium with a rare earth metal as the next major constituent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/46—Alloys based on magnesium or aluminium
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Power Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Electric Double-Layer Capacitors Or The Like (AREA)
Description
本発明は、電気化学デバイス用電極材に関するものである。 The present invention relates to an electrode material for electrochemical devices.
電気化学デバイス用電極材は、たとえば２次電池の負極に用いる場合、マグネシウム金属が高い理論容量（３８３０Ａｈｄｍ-3、リチウム金属：２０６０Ａｈｄｍ-3）を有し、正負極が短絡するデンドライトが起こりにくく、大気中でハンドリングしやすいこと等から、実用的な高容量電気化学デバイス用電極材として期待されている。しかしながら、マグネシウムあるいはマグネシウム合金（以下、合金も含めてマグネシウム金属と呼ぶことがある）電極の表面には不働態被膜が形成されやすく、充放電サイクルが著しく劣化することが知られている。 When the electrode material for electrochemical devices is used, for example, as the negative electrode of a secondary battery, magnesium metal has a high theoretical capacity (3830 Ahdm -3 , lithium metal: 2060 Ahdm -3 ), and dendrites that short-circuit the positive and negative electrodes are unlikely to occur. Because it is easy to handle in the atmosphere, it is expected to be a practical electrode material for high-capacity electrochemical devices. However, it is known that a passive film is likely to be formed on the surface of a magnesium or magnesium alloy (hereinafter, the alloy may also be referred to as magnesium metal) electrode, which significantly deteriorates the charge/discharge cycle.
この課題を解決する方法として、特許文献１には、この不働態被膜を電池駆動中に除去する方法が記載されている。特許文献２には、溶液に浸漬して、不働態被膜を除去する方法が記載されている。特許文献３には、働態化被膜を形成する電解液が記載されている。 As a method for solving this problem, Patent Document 1 describes a method of removing this passive film during battery operation. Patent Document 2 describes a method of removing a passive film by immersing it in a solution. Patent Document 3 describes an electrolytic solution that forms an activation film.
従来のマグネシウム金属電極、特にＡｌやＺｎ等を含むマグネシウム合金電極には、上記不働態被膜が形成する課題に加えて、電流密度が低い、すなわち、電気化学的な活性が低いことに課題があった。このため、マグネシウム金属製電気化学デバイスは高出力や急速充電が必要となる用途では、実施を期待することができなかった。これは、通常のマグネシウム金属は六方晶の底面すなわち（０００１）面が表面に平行に配列する集合組織が形成され、この面に強固な不働態皮膜が形成されるため酸化還元に対して安定となる、すなわち、電気化学的に不活性となるからである。
先行技術文献である特許文献１～３にはいずれも形成された不働態被膜を除去する方法もしくは電解液により不働態化を防ぐ方法が開示されている。しかしながら、これらの方法は不働態化を抑制するものであり、マグネシウム金属電極自体の電流密度を増大させ、電気化学的に活性化するものではない。
したがって、本発明は、電気化学的に活性な、マグネシウム金属製電気化学デバイス用電極材を提供することを目的とする。
Conventional magnesium metal electrodes, particularly magnesium alloy electrodes containing Al, Zn, etc., have the problem of low current density, that is, low electrochemical activity, in addition to the problem of the formation of the passive film described above. Ta. For this reason, electrochemical devices made of magnesium metal cannot be expected to be used in applications that require high output or rapid charging. This is because ordinary magnesium metal has a texture in which the hexagonal bottom plane, or (0001) plane, is arranged parallel to the surface, and a strong passive film is formed on this plane, making it stable against oxidation and reduction. This is because it becomes electrochemically inactive.
Patent Documents 1 to 3, which are prior art documents, all disclose a method of removing a formed passive film or a method of preventing passivation using an electrolytic solution. However, these methods suppress passivation, increase the current density of the magnesium metal electrode itself, and do not electrochemically activate it.
Therefore, an object of the present invention is to provide an electrochemically active electrode material for an electrochemical device made of magnesium metal.
本発明者らは、全く視点を変え、マグネシウム合金の組成を変えることによりマグネシウム元素を有する電極自体を電気化学的に活性化する方法を検討した。本発明は、この際の知見に基づいてなされたものであり、その技術的特徴はマグネシウム合金の成分としてＣｕを含むことにある。 The present inventors completely changed their viewpoint and investigated a method of electrochemically activating the electrode itself containing the magnesium element by changing the composition of the magnesium alloy. The present invention was made based on this knowledge, and its technical feature is that the magnesium alloy contains Cu as a component.
本発明者らは、マグネシウム合金にＣｕを添加すると電気化学デバイスとしての性能が格段に向上することを見出した。本発明は、この知見に基づいてなされたものであり、Ｃｕ含有の効果としては、理論に縛られるものではないが以下のように考えられる。Ｃｕを含有すると導電性の高いＭｇ2Ｃｕ化合物がネットワーク状に配置した構造となり、導電パスが形成される。図１は、質量％で、Ｃｕを１％（記号Ｃ１０）、３％（記号Ｃ３０）、およびＣｕ５％とＭｎ０．５％（記号ＣＭ５００５）を含有したマグネシウム合金の顕微鏡組織写真である。図１の組織をＸＲＤにより解析した結果を図２に示す。図１、図２からＣｕを含有するマグネシウム合金にはネットワーク状に配置されたＭｇ2Ｃｕ化合物が存在していることがわかる（黒色部分）。このＭｇ2Ｃｕ近傍では、Ｍｇ2ＣｕとＭｇとの間で電子授受反応（局所電池反応）が起こり、電気化学的に活性化すると考えられる。さらに、Ｃｕの比率を上げると、Ｍｇ2Ｃｕネットワークが増大するため、電気化学的に活性なサイトが増大する。これらのことから、電気化学デバイスとしての性能が格段に向上するものと考えられる。 The present inventors have discovered that adding Cu to a magnesium alloy significantly improves its performance as an electrochemical device. The present invention was made based on this knowledge, and the effect of containing Cu is thought to be as follows, although it is not bound by theory. When Cu is contained, a structure in which highly conductive Mg 2 Cu compounds are arranged in a network form is formed, and a conductive path is formed. FIG. 1 is a microscopic structure photograph of a magnesium alloy containing 1% (symbol C10), 3% (symbol C30) of Cu, and 5% Cu and 0.5% Mn (symbol CM5005) in terms of mass %. FIG. 2 shows the results of analyzing the structure in FIG. 1 by XRD. It can be seen from FIGS. 1 and 2 that Mg 2 Cu compounds arranged in a network are present in the magnesium alloy containing Cu (black portion). It is thought that an electron transfer reaction (local battery reaction) occurs between Mg 2 Cu and Mg in the vicinity of this Mg 2 Cu , resulting in electrochemical activation. Furthermore, increasing the Cu ratio increases the Mg 2 Cu network, thereby increasing the number of electrochemically active sites. For these reasons, it is thought that the performance as an electrochemical device will be significantly improved.
さらに本発明の好ましい態様として、Ｃｕ添加に加えて、電気化学デバイス用電極材として用いる際の表面からＸＲＤにより測定した（０００２）面極点図において、表面の法線方向に極大値を持たないマグネシウム合金を用いることが挙げられる。
マグネシウムは、六方晶の底面すなわち（０００１）面が酸化還元に対して安定であることを出願人らは見出した。一般的な金属では、原子配列の最密面が電気化学的に活性であることが確認されているが、マグネシウムは一般の金属とは異なり、原子配列の最密面である（０００１）面が電気化学反応においては安定であった。この理由は明確ではないが、（０００１）面に強固な不働態皮膜が容易に形成されるためと考えられる。このため、（０００１）面が反応面に現れている状態で電気化学デバイスの電極を形成すると、電極面は酸化還元反応が起こりにくい、すなわち、電気化学的な活性が低い（電流密度が低い）ものとなる。
これに対して、電極材の表面に（０００１）面以外の面を露出することができれば、マグネシウム金属を電気化学的に活性化し、電気化学デバイスとしての充放電時間が短縮できる、すなわち、高出力化および急速充電が可能となるものと推察される。
本発明者らは、電気化学デバイス用電極材の表面とマグネシウム合金の（０００１）面を傾斜するように配置することにより表面に（０００１）面以外の面を露出すると、Ｃｕを含むマグネシウム合金を電気化学的にさらに活性化して課題を達成できることを見いだした。
本明細書において電極材の「表面」とは、電気化学デバイスにおいて電極材を使用した際に電極反応に主として寄与する表面（「主たる反応面」ともいう）を意味する。電極反応に主として寄与する表面あるいは主たる反応面とは、電気化学反応に主として係る面を指し、たとえば通常の板のように６面で構成される電極では最も面積の大きい面を指し、円筒状の電極では円筒の端面ではなく側面の面積の広い面を指し、円盤状の電極では側面ではなく上下の円形の面などを指す。
Ｃｕ３％を含有する圧延板の板表面から測定した（０００２）面極点図は図３のようになり、（０００１）面がほとんど板表面の法線方向に向いている。これに対し、Ｃｕ３％にさらにＺｎ１．５％、Ｃａ０．１％を加えると図４のように（０００２）面の極大値が２つあり、その位置が板表面の法線方向から傾いて存在していることがわかる。このように、Ｃｕに他の元素を加えて表面法線方向への（０００１）面の集積を緩和すればさらに電気化学デバイスとしての性能が向上することが期待できる。
Furthermore, as a preferred embodiment of the present invention, in addition to Cu addition, magnesium has no maximum value in the normal direction of the surface in the (0002) plane pole figure measured by XRD from the surface when used as an electrode material for an electrochemical device. An example of this is to use an alloy.
Applicants have discovered that the base of the hexagonal crystal, that is, the (0001) plane, of magnesium is stable against redox. It has been confirmed that in common metals, the closest-packed plane of the atomic arrangement is electrochemically active, but unlike other metals, magnesium has the (0001) plane, which is the closest-packed plane of the atomic arrangement. It was stable in electrochemical reactions. Although the reason for this is not clear, it is thought that it is because a strong passive film is easily formed on the (0001) plane. For this reason, if an electrode for an electrochemical device is formed with the (0001) plane appearing on the reaction surface, redox reactions are unlikely to occur on the electrode surface, that is, electrochemical activity is low (current density is low). Become something.
On the other hand, if a plane other than the (0001) plane can be exposed on the surface of the electrode material, the magnesium metal can be electrochemically activated and the charging/discharging time as an electrochemical device can be shortened, i.e., high output It is presumed that this will enable faster charging and faster charging.
The present inventors discovered that when the surface of an electrode material for an electrochemical device and the (0001) plane of the magnesium alloy are arranged so as to be inclined, and a plane other than the (0001) plane is exposed on the surface, a magnesium alloy containing Cu is formed. It was discovered that the task could be achieved by further activating it electrochemically.
In this specification, the "surface" of an electrode material means a surface that mainly contributes to electrode reaction (also referred to as "main reaction surface") when the electrode material is used in an electrochemical device. The surface that mainly contributes to the electrode reaction or the main reaction surface refers to the surface that is mainly involved in the electrochemical reaction. For example, in the case of an electrode consisting of six surfaces like a normal plate, it refers to the surface with the largest area. For electrodes, it refers to the wide side surface of a cylinder, not the end surface, and for disk-shaped electrodes, it refers to the upper and lower circular surfaces, rather than the side surfaces.
The (0002) plane pole figure measured from the plate surface of a rolled plate containing 3% Cu is as shown in FIG. 3, and the (0001) plane is almost oriented in the normal direction of the plate surface. On the other hand, when 1.5% Zn and 0.1% Ca are added to 3% Cu, there are two maximum values on the (0002) plane as shown in Figure 4, and their positions are tilted from the normal direction of the plate surface. I know what you're doing. In this way, if other elements are added to Cu to alleviate the accumulation of (0001) planes in the surface normal direction, it can be expected that the performance as an electrochemical device will be further improved.
本発明は、Ｃｕ添加の効果に加えて前記知見に基づいてなされたものであり、以下の技術要素から構成される。
（１）Ｃｕを含有するマグネシウム合金を用いた電気化学デバイス用電極材。
（２）Ｃｕの含有量が質量％で０．３～１５．０％である（１）記載の電気化学デバイス用電極材。
（３）質量％でＺｎを０．５～３．５％、およびＣａを０．１～１．０％の少なくとも一方をさらに含有する（１）または（２）記載の電気化学デバイス用電極材。
（４）Ｃ、Ｓｉ、Ｇｅ，Ｓｎ、およびＰｂからなる群より選ばれる少なくとも１種の周期律表の４Ｂ元素を質量％で合計０．０１～５．０％の範囲でさらに含有する（１）から（３）のいずれか一記載の電気化学デバイス用電極材。
（５）Ｓｃ，Ｙ、Ｌａ、Ｃｅ、Ｐｒ，Ｎｄ、およびＳｍからなる群より選ばれる少なくとも１種の希土類元素を質量％で合計０．０１～３．０％の範囲でさらに含有する（１）から（４）のいずれか一記載の電気化学デバイス用電極材。
（６）希土類元素を、ミッシュメタルの形態で含有し、ミッシュメタルの含有量が質量％で０．０１～３．０％である（５）記載の電気化学デバイス用電極材。
（７）ＭｎおよびＺｒの少なくとも一方を質量％で０．２～３．０％の範囲でさらに含有する（１）から（６）のいずれか一記載の電気化学デバイス用電極材。
（８）電気化学デバイスとして用いたときの電気化学デバイス用電極材の表面方向からＸＲＤにより測定した（０００２）面極点図において、表面の法線方向に極大値を持たないことを特徴とする、（１）から（７）のいずれか一記載の電気化学デバイス用電極材。
The present invention has been made based on the above-mentioned findings in addition to the effects of adding Cu, and is comprised of the following technical elements.
(1) Electrode material for electrochemical devices using a magnesium alloy containing Cu.
(2) The electrode material for an electrochemical device according to (1), wherein the Cu content is 0.3 to 15.0% by mass.
(3) The electrode material for an electrochemical device according to (1) or (2), further containing at least one of 0.5 to 3.5% by mass of Zn and 0.1 to 1.0% of Ca. .
(4) Further contains at least one 4B element of the periodic table selected from the group consisting of C, Si, Ge, Sn, and Pb in a total range of 0.01 to 5.0% by mass (1 The electrode material for an electrochemical device according to any one of ) to (3).
(5) Further contains at least one rare earth element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, and Sm in a total range of 0.01 to 3.0% by mass (1 ) to (4), the electrode material for an electrochemical device according to any one of (4).
(6) The electrode material for an electrochemical device according to (5), which contains the rare earth element in the form of misch metal, and the content of misch metal is 0.01 to 3.0% by mass.
(7) The electrode material for an electrochemical device according to any one of (1) to (6), further containing at least one of Mn and Zr in a range of 0.2 to 3.0% by mass.
(8) In the (0002) plane pole figure measured by XRD from the surface direction of the electrode material for an electrochemical device when used as an electrochemical device, it is characterized by not having a maximum value in the normal direction of the surface. The electrode material for an electrochemical device according to any one of (1) to (7).
本発明の他の好ましい実施態様としては以下が挙げられる。
（１）Ｃｕを含有するマグネシウム合金を用いた電極材。
（２）Ｃｕの含有量が質量％で０．３～１５．０％である（１）記載の電極材。
（３）質量％でＺｎを０．５～３．５％、およびＣａを０．１～１．０％の少なくとも一方をさらに含有する（１）または（２）記載の電極材。
（４）Ｃ、Ｓｉ、Ｇｅ，Ｓｎ、およびＰｂからなる群より選ばれる少なくとも１種の周期律表の４Ｂ元素を質量％で合計０．０１～５．０％の範囲でさらに含有する（１）から（３）のいずれか一記載の電極材。
（５）Ｓｃ，Ｙ、Ｌａ、Ｃｅ、Ｐｒ，Ｎｄ、およびＳｍからなる群より選ばれる少なくとも１種の希土類元素を質量％で合計０．０１～３．０％の範囲でさらに含有する（１）から（４）のいずれか一記載の電極材。
（６）希土類元素を、ミッシュメタルの形態で含有し、ミッシュメタルの含有量が質量％で０．０１～３．０％である（５）記載の電極材。
（７）ＭｎおよびＺｒの少なくとも一方を質量％で０．２～３．０％の範囲でさらに含有する（１）から（６）のいずれか一記載の電極材。
（８）（１）から（７）のいずれか一記載の電極材を含む電気化学デバイス。
（９）電極材の表面方向からＸＲＤにより測定した（０００２）面極点図において、表面の法線方向に極大値を持たないことを特徴とする、（８）に記載の電気化学デバイス。
Other preferred embodiments of the present invention include the following.
(1) Electrode material using a magnesium alloy containing Cu.
(2) The electrode material according to (1), wherein the Cu content is 0.3 to 15.0% by mass.
(3) The electrode material according to (1) or (2), further containing at least one of 0.5 to 3.5% by mass of Zn and 0.1 to 1.0% of Ca.
(4) Further contains at least one 4B element of the periodic table selected from the group consisting of C, Si, Ge, Sn, and Pb in a total range of 0.01 to 5.0% by mass (1 ) to (3).
(5) Further contains at least one rare earth element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, and Sm in a total range of 0.01 to 3.0% by mass (1 ) to (4).
(6) The electrode material according to (5), which contains the rare earth element in the form of misch metal, and the content of misch metal is 0.01 to 3.0% by mass.
(7) The electrode material according to any one of (1) to (6), further containing at least one of Mn and Zr in a range of 0.2 to 3.0% by mass.
(8) An electrochemical device comprising the electrode material according to any one of (1) to (7).
(9) The electrochemical device according to (8), wherein the (0002) plane pole figure measured by XRD from the surface direction of the electrode material has no maximum value in the normal direction of the surface.
本発明のマグネシウム合金を用いた電気化学デバイス用電極材は、２次電池、キャパシタ等の電気化学デバイスに用いたときに、充放電サイクルを繰り返しても高い電流密度を維持できることができる。不働態被膜が形成されにくくなり、充放電の回数を伸ばすことができたものと考えられる。 When the electrode material for electrochemical devices using the magnesium alloy of the present invention is used in electrochemical devices such as secondary batteries and capacitors, it is possible to maintain a high current density even after repeated charge/discharge cycles. It is thought that the formation of a passive film became difficult and the number of charging and discharging cycles could be increased.
本発明の特徴は、Ｃｕを含有するマグネシウム合金を電気化学デバイス用電極材として用いることにあり、Ｃｕの含有量の好適な範囲は質量％で０．３～１５．０％である。Ｃｕの含有量が、０．３％未満の場合、電気化学デバイスに用いる電極材として電流密度を増大させる効果が小さくなるので、少なくとも０．３％以上含有させることが好ましい。Ｃｕの比率を上げすぎると、板材とするときの圧延が困難となる傾向にあるため、Ｃｕの含有量は１５％以下が好ましい。
Ｃｕの含有量は、より好ましくは１．５～１３．０％であり、さらに好ましくは２．５～１２．０％である。
A feature of the present invention is that a magnesium alloy containing Cu is used as an electrode material for an electrochemical device, and a preferable range of the Cu content is 0.3 to 15.0% by mass. When the Cu content is less than 0.3%, the effect of increasing current density as an electrode material used in an electrochemical device becomes small, so it is preferable to contain at least 0.3% or more. If the Cu ratio is increased too much, it tends to become difficult to roll the sheet material, so the Cu content is preferably 15% or less.
The Cu content is more preferably 1.5 to 13.0%, even more preferably 2.5 to 12.0%.
マグネシウム合金のＣｕ以外の成分としては、特に制限するものではないが、金属のマグネシウム以外は不可避的不純物のみからなってもよく、また以下に述べる他の成分を含んでいてもよい。
また他の態様として、マグネシウム合金のＣｕ以外の成分としては、特に制限するものではないが、好ましくは、質量％でＺｎを０．１～３．５％、およびＣａを０．０５～１．０％の少なくとも一方を含有する。前述のごとく本発明者らは、Ｃｕ添加の効果に加えてさらに電気化学デバイスの充放電特性と六方晶の各面との関係を検討した結果、デバイス表面に（０００１）面が強く集積していない方が良い結果をもたらすことを確認した。通常の鋳塊あるいは展伸材は、表面の法線方向に六方晶の（０００１）面が極端に強く集積した集合組織を有する。これに対し、質量％でＺｎを０．１～３．５％、およびＣａを０．０５～１．０％の少なくとも一方を含有するとこの集積が弱くなり、（０００１）面以外の面が表面に露出することになる。このため、Ｚｎを０．１～３．５％、およびＣａを０．０５～１．０％の少なくとも一方を含有することが好ましい。いずれの化学成分もその含有量が少ないと（０００１）面の集積度を弱める効果が小さくなり、また多すぎてもその効果が無くなる。さらには、Ｃａは１．０％以上含有すると、圧延板を製造することが困難になる傾向があるので、上限を１．０％とすることが好ましい。
Ｚｎのより好ましい含有量は０．５～２．５％であり、さらに好ましい含有量は１．０～２．０％である。Ｃａのより好ましい含有量は０．１～０．９％である。
Components other than Cu in the magnesium alloy are not particularly limited, but the magnesium alloy may consist only of inevitable impurities other than metal magnesium, or may contain other components described below.
In another embodiment, the components other than Cu in the magnesium alloy are not particularly limited, but preferably include 0.1 to 3.5% by mass of Zn and 0.05 to 1.5% by mass of Ca. Contains at least one of 0%. As mentioned above, in addition to the effect of Cu addition, the present inventors further investigated the relationship between the charge/discharge characteristics of electrochemical devices and each face of the hexagonal crystal, and found that (0001) planes were strongly integrated on the device surface. It was confirmed that the results were better without it. A normal ingot or wrought material has a texture in which hexagonal (0001) planes are extremely concentrated in the normal direction of the surface. On the other hand, if at least one of 0.1 to 3.5% of Zn and 0.05 to 1.0% of Ca is contained by mass, this accumulation becomes weaker, and planes other than the (0001) plane become will be exposed to. Therefore, it is preferable to contain at least one of 0.1 to 3.5% Zn and 0.05 to 1.0% Ca. If the content of any chemical component is small, the effect of weakening the degree of integration of the (0001) plane will be small, and if the content is too large, the effect will be lost. Furthermore, if Ca is contained in an amount of 1.0% or more, it tends to become difficult to produce a rolled plate, so the upper limit is preferably 1.0%.
A more preferable content of Zn is 0.5 to 2.5%, and an even more preferable content is 1.0 to 2.0%. A more preferable content of Ca is 0.1 to 0.9%.
さらに上記化学成分に加えて、Ｃ、Ｓｉ、Ｇｅ，Ｓｎ、およびＰｂからなる群より選ばれる少なくとも１種以上の周期律表の４Ｂ族元素を加えても、Ｚｎ、Ｃａの場合と同じような効果が発揮でき、表面の法線方向への（０００１）面の集積を弱くする傾向にある。このため、これらの元素を質量％で合計０．０１～５．０％含有することが好ましい。いずれの元素も０．０１％未満ではその効果が小さくなり、また５．０％を超えると板材の製造が困難になる傾向にあるので、この値を上限とすることが好ましい。より好ましい範囲としては、合計で０．１～２．０％である。 Furthermore, in addition to the above chemical components, even if at least one or more group 4B elements of the periodic table selected from the group consisting of C, Si, Ge, Sn, and Pb are added, the same effects as in the case of Zn and Ca can be obtained. This has a tendency to weaken the accumulation of (0001) planes in the normal direction of the surface. Therefore, it is preferable that these elements be contained in a total amount of 0.01 to 5.0% by mass. If the content of any element is less than 0.01%, the effect will be reduced, and if it exceeds 5.0%, it will tend to be difficult to manufacture the plate material, so it is preferable to set this value as the upper limit. A more preferable range is 0.1 to 2.0% in total.
さらにＳｃ，Ｙ、Ｌａ、Ｃｅ、Ｐｒ，Ｎｄ、およびＳｍからなる群より選ばれる少なくとも１種以上の希土類元素を質量％で合計０．０１～３．０％を含有しても（０００１）面の集積を弱くする効果が得られるので、これらの元素を添加することも好ましい。含有量の上下限を外れると、いずれも（０００１）面の集積を弱くする効果が低くなるので、この値を上下限とすることが好ましい。より好ましい範囲としては、合計で０．１～２．０％である。 Furthermore, even if a total of 0.01 to 3.0% by mass of at least one rare earth element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, and Sm is contained, the (0001) plane It is also preferable to add these elements because they have the effect of weakening the accumulation of. If the content exceeds the upper and lower limits, the effect of weakening the accumulation of (0001) planes will decrease, so it is preferable to set these values as the upper and lower limits. A more preferable range is 0.1 to 2.0% in total.
希土類元素を添加する際に、希土類元素の混合物であるミッシュメタルを使用することもできる。希土類元素を単体で添加するよりもその混合体であるミッシュメタルを使用した方が容易に希土類元素を添加できる。その含有量は、上記希土類元素の含有量と同じ０．０１～３．０％とする。含有量の上下限を外れると、いずれも（０００１）面の集積を弱くする効果が小さくなるので、この値を上下限とすることが好ましい。より好ましい範囲としては、０．１～２．０％である。 When adding rare earth elements, misch metal, which is a mixture of rare earth elements, can also be used. Rare earth elements can be added more easily by using misch metal, which is a mixture of rare earth elements, than by adding rare earth elements alone. Its content is 0.01 to 3.0%, which is the same as the rare earth element content. If the content exceeds the upper and lower limits, the effect of weakening the accumulation of (0001) planes becomes smaller, so it is preferable to set these values as the upper and lower limits. A more preferable range is 0.1 to 2.0%.
さらに好ましくは、ＭｎおよびＺｒの少なくとも一方を質量％で０．２～３．０％含有させる。この理由としては、ＭｎおよびＺｒを含有すると結晶粒径が小さくなり、（０００１）面以外の面が表面に露出する確率が高くなるためである。しかし、０．２％未満ではその効果が小さくなり、また３．０％を超えて含有すると板材の製造が困難になる傾向にあるので、上限を３．０％とすることが好ましい。より好ましい範囲としては、０．２～２．０％である。 More preferably, at least one of Mn and Zr is contained in an amount of 0.2 to 3.0% by mass. The reason for this is that when Mn and Zr are contained, the crystal grain size becomes smaller and the probability that planes other than the (0001) plane are exposed on the surface increases. However, if the content is less than 0.2%, the effect will be reduced, and if the content exceeds 3.0%, it will tend to be difficult to manufacture plate materials, so it is preferable to set the upper limit to 3.0%. A more preferable range is 0.2 to 2.0%.
本発明に記載したＣｕを含有するマグネシウム合金の製造工程は以下のとおりである。まず、高純度のマグネシウム地金を溶解し、歩留まりを考慮した必要量の添加元素を加え、スラブあるいはビレットとなす。スラブの場合は、粗圧延、仕上圧延を経て、コイル状あるいは切り板状の板とする。圧延は、必要に応じて温間で行う。ビレットの場合は、押し出しにより、板状とする。そのまま用いてもよいが、さらに薄くするには圧延を施す。板厚は特に規定しないが、使用される電気化学デバイスに応じて所望される板厚とする。圧延では、板厚数十ミクロンの箔を製造することが可能なので、特に薄型の電気化学デバイスでは箔を用いることが好ましい。 The manufacturing process of the Cu-containing magnesium alloy described in the present invention is as follows. First, a high-purity magnesium ingot is melted, and the necessary amount of additive elements are added in consideration of the yield to form a slab or billet. In the case of a slab, it is rough rolled and finished rolled into a coiled or cut plate. Rolling is performed warmly if necessary. In the case of a billet, it is made into a plate shape by extrusion. It may be used as is, but it may be rolled to make it even thinner. Although the plate thickness is not particularly specified, it is set to a desired plate thickness depending on the electrochemical device used. By rolling, it is possible to produce a foil with a thickness of several tens of microns, so it is preferable to use foil especially in thin electrochemical devices.
上記方法によって製造された板材を電気化学デバイス用電極に用いることができる。
本明細書において電気化学デバイスとは、電気エネルギーと化学エネルギーを変換するデバイスであり、具体的には、１次電池、２次電池、燃料電池などが挙げられる。電気化学デバイスが２次電池である場合には、例えば、２つの電極、セパレータおよび電解液から構成されていてもよい。
本発明に係る電極に対する対極は、活物質、導電助剤、バインダーを混錬して、集電箔に塗工して作製される。活物質は、マグネシウムイオンを吸蔵放出可能な物質、例えば、五酸化バナジウムや活性炭を用いることができる。
セパレータは、電解液が濡れるもので、マグネシウムイオンを透過できるものであり、ポリプロピレン等を利用することができる。
電解液は、マグネシウム金属表面にマグネシウムイオンが透過可能な被膜が形成されるもので、例えば、無水こはく酸添加グライム電解液（特許文献３）を利用することができる。この電解液を用いることにより、マグネシウム合金の不働態化を抑制することができる。
The plate material manufactured by the above method can be used as an electrode for an electrochemical device.
In this specification, an electrochemical device is a device that converts electrical energy and chemical energy, and specifically includes a primary battery, a secondary battery, a fuel cell, and the like. When the electrochemical device is a secondary battery, it may be composed of, for example, two electrodes, a separator, and an electrolyte.
The counter electrode to the electrode according to the present invention is prepared by kneading an active material, a conductive additive, and a binder and applying the mixture to a current collector foil. As the active material, a substance that can absorb and release magnesium ions, such as vanadium pentoxide and activated carbon, can be used.
The separator is wetted by the electrolyte and is permeable to magnesium ions, and polypropylene or the like can be used as the separator.
The electrolytic solution forms a film on the magnesium metal surface through which magnesium ions can permeate, and for example, succinic anhydride-added glyme electrolytic solution (Patent Document 3) can be used. By using this electrolytic solution, passivation of the magnesium alloy can be suppressed.
以下、本発明を実施例に基づいて具体的に説明する。
以下において「％」は特に示さない限り「質量％」を意味する。
表１に示すマグネシウム合金を溶製し、圧延後０．４ｍｍの板とした。これらの板を用いて以下に示す電気化学的な評価を行った。
電気化学的な評価は、ビーカー式３極セルを用いて行った。作用極に、マグネシウム合金、対極に活性炭電極、参照極に銀電極、電解液には無水こはく酸添加グライム電解液（特開２０１７－０２２０２４）を用いた。３５℃で、所定電流を印加したときのマグネシウム合金の酸還元電位を測定した。
本発明では、実用上の利用価値があると考えられるフラットな電圧が維持できる電流密度が９０μＡｃｍ-2以上である場合、電気化学デバイスとして利用できると判断した。
ここでいうフラットな電圧が維持できる状態とは、酸化還元電流密度と電位の関係を測定した結果の図において、横軸のＣａｐａｃｉｔｙが２０μＡｈと１２０μＡｈのときの電圧を比較して、その差が０．１Ｖ以内の状態を指す。２０μＡｈまでの間では、測定初期の不安定さが残るので、この間の変化を除いて評価した。
ＸＲＤによる極点図の測定は、株式会社リガク製Ｘ線回折装置 ＲＩＮＴ２０００／ＰＣを用いて、シュルツ反射法により行った。測定面を（０００２）面とし、管電流４０ｍＡ、管電圧４０ＫＶにて測定した。（０００２）面のＸ線反射強度は、２θ＝３４．５度付近にピークが出るが、２θ＝３０度では反射強度のピークを現れないので、この角度で測定した値をバックグラウンドの値とした。
また、電気化学デバイスとしての性能としては、酸化と還元の電位差が小さい方が優れていると判断できる。
以下、その結果である。
Hereinafter, the present invention will be specifically explained based on Examples.
In the following, "%" means "% by mass" unless otherwise specified.
The magnesium alloy shown in Table 1 was melted and rolled into a 0.4 mm plate. The following electrochemical evaluations were performed using these plates.
Electrochemical evaluation was performed using a beaker-type three-electrode cell. A magnesium alloy was used as a working electrode, an activated carbon electrode was used as a counter electrode, a silver electrode was used as a reference electrode, and a succinic anhydride-added glyme electrolyte (Japanese Patent Application Laid-Open No. 2017-022024) was used as an electrolyte. The acid reduction potential of the magnesium alloy was measured at 35° C. when a predetermined current was applied.
In the present invention, it has been determined that if the current density at which a flat voltage can be maintained, which is considered to have practical utility, is 90 μAcm -2 or more, it can be used as an electrochemical device.
Here, the state where a flat voltage can be maintained means that in the diagram of the result of measuring the relationship between redox current density and potential, when the voltages when the horizontal axis Capacity is 20 μAh and 120 μAh are compared, the difference between them is 0. .1V or less. Up to 20 μAh, instability at the initial stage of measurement remains, so the evaluation was performed excluding changes during this period.
The measurement of the pole figure by XRD was performed by the Schulz reflection method using an X-ray diffractometer RINT2000/PC manufactured by Rigaku Co., Ltd. The measurement plane was set to the (0002) plane, and the measurement was performed at a tube current of 40 mA and a tube voltage of 40 KV. The X-ray reflection intensity of the (0002) plane has a peak near 2θ = 34.5 degrees, but the peak of reflection intensity does not appear at 2θ = 30 degrees, so the value measured at this angle is used as the background value. did.
Furthermore, it can be determined that the smaller the potential difference between oxidation and reduction, the better the performance as an electrochemical device.
Below are the results.
（比較例１）Ａｌ－Ｚｎ合金（ＡＺ合金）
Ａｌ３％、Ｚｎ１％を含有し、残部マグネシウムからなる一般的に圧延材として用いられるＡＺ３１合金の酸化還元電位を図５に示す。還元電流密度が３０μＡｃｍ-2まではフラットな電位を維持するが、６０μＡｃｍ-2以上では還元電位が大幅に負の方向に増大し、フラット電位が継続できなくなった。これは印加した電流密度に対して、電極反応が間に合わない、すなわち、電極の電気化学的に活性なサイト数が不足していることを示唆している。特に還元反応は酸化反応に比べて遅いため、この活性サイト数不足が顕著となる。フラット電位が継続しない状態では、電解液の分解が進行し、電極は不働態化するので、電気化学デバイスとして安定して動作させるには、フラット電位が維持できる電流密度３０μＡｃｍ-2以下にしなければならず、実用に供するには低すぎる電流密度であり、電気化学デバイス用電極材としての利用価値はない。
(Comparative Example 1) Al-Zn alloy (AZ alloy)
FIG. 5 shows the oxidation-reduction potential of the AZ31 alloy, which contains 3% Al, 1% Zn, and the balance is magnesium, and is generally used as a rolled material. A flat potential was maintained up to a reduction current density of 30 μAcm −2 , but at a reduction current density of 60 μAcm −2 or more, the reduction potential significantly increased in the negative direction and the flat potential could no longer be maintained. This suggests that the electrode reaction is not in time for the applied current density, that is, the number of electrochemically active sites on the electrode is insufficient. In particular, since the reduction reaction is slower than the oxidation reaction, this lack of active sites becomes noticeable. If the flat potential does not continue, the electrolyte will decompose and the electrode will become passivated, so in order to operate stably as an electrochemical device, the current density must be lower than 30 μAcm -2 to maintain the flat potential. However, the current density is too low for practical use, and it has no value as an electrode material for electrochemical devices.
（比較例２）
純度９９．９９９％の純Ｍｇの酸化還元電位を図６に示す。還元電流密度が９０μＡｃｍ-2でフラット電位が継続しなくなった。このため、電気化学デバイスとして実用上の利用価値は小さいと判断した。
(Comparative example 2)
FIG. 6 shows the redox potential of pure Mg with a purity of 99.999%. The flat potential no longer continued when the reduction current density was 90 μAcm −2 . For this reason, it was determined that the practical use value as an electrochemical device is small.
（実施例１）Ｃｕ添加合金（以下Ｃ合金と称す。記号のＣ以下の数値１０～１００は、それぞれＣｕを概ね１．０％～１０．０％含有していることを表す。以下、同様に各元素の概ねの含有量を示す。）
Ｃ１０、Ｃ３０、Ｃ１００の酸化還元電位を図７から図９に示す。Ｃ合金は、ＡＺ３１合金に比べて、高い還元電流密度までフラット電位が維持されている。Ｃｕが１．０％では９０μＡｃｍ-2まで、Ｃｕが３．０％では概ね１２０μＡｃｍ-2まで、Ｃｕが１０．０％では１８０μＡｃｍ-2までフラットな電位が維持されている。Ｃｕの割合が高いほど、より高い還元電流密度までフラット電位が維持されることがわかる。また、電流密度を上げたときの酸化電位と還元電位の差も小さくなる。これは、Ｃｕを含有したマグネシウム合金は、一般的なＡｌ－Ｚｎ合金より電気化学的に活性なサイトが多く、電流密度６倍以上の高い電流を印加しても安定して充放電できることを示唆している。したがって、Ｃｕを含有したマグネシウム合金を用いると高出力で急速充電が可能な電気化学デバイスが実現できることを示している。
(Example 1) Cu-added alloy (hereinafter referred to as C alloy. The numbers 10 to 100 below C in the symbol each represent approximately 1.0% to 10.0% Cu content. The same applies hereinafter. shows the approximate content of each element.)
The redox potentials of C10, C30, and C100 are shown in FIGS. 7 to 9. Compared to the AZ31 alloy, the C alloy maintains a flat potential up to a high reduction current density. A flat potential is maintained up to 90 μAcm −2 when Cu is 1.0%, approximately 120 μAcm −2 when Cu is 3.0%, and 180 μAcm −2 when Cu is 10.0%. It can be seen that the higher the proportion of Cu, the more the flat potential is maintained up to a higher reduction current density. Furthermore, the difference between the oxidation potential and the reduction potential becomes smaller when the current density is increased. This suggests that the Cu-containing magnesium alloy has more electrochemically active sites than general Al-Zn alloys, and can be stably charged and discharged even when applied with a current that is more than 6 times as high as the current density. are doing. Therefore, it is shown that an electrochemical device capable of high output and rapid charging can be realized by using a magnesium alloy containing Cu.
（実施例２）Ｃｕ-Ｚｎ合金（ＣＺ合金）
Ｃｕ添加の効果に加えて、（０００１）面を表面の法線方向から傾けた効果を調べる一例として、ＣＺ３０１５の集合組織と酸化還元電位を測定した。（０００２）面極点図を図１０に示す。極点図の縦横の軸の目盛りはそれぞれ法線方向からの角度１０度ごとを示す。Ｃｕ３．０％のみ含む合金の極点図は図３に示すものであり、その極大を示す点は、図の中心からわずかに傾斜しているが、そのずれは１０度以内である。これに対して、図１０に示すＣＺ３０１５合金では、その傾斜が約１５度あり、Ｃｕを単独で含有するものよりも（０００１）面が表面の法線方向からの傾斜が大きくなっている。このＣＺ３０１５合金の酸化還元電流密度と電位の関係を調べた結果を図１１に示す。Ｃｕを単独で３．０％含む合金の、１２０μＡｈにおける酸化電流密度９００μＡｃｍ-2と還元電流密度１８０μＡｃｍ-2との電位差は、図８から０．３３Ｖと読み取れる。これに対し、ＣｕにさらにＺｎを加えたＣ３０１５合金の電位差は図１１から０．２５Ｖと読み取れ、Ｚｎを加え、（０００１）面を表面の法線方向から傾けることによって電気化学デバイスとしての性能が向上していることがわかる。
図１１から、この合金は高い酸化還元電流密度までフラットな電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電ができることを示唆している。
(Example 2) Cu-Zn alloy (CZ alloy)
In addition to the effect of adding Cu, as an example of investigating the effect of tilting the (0001) plane from the normal direction of the surface, the texture and redox potential of CZ3015 were measured. The (0002) surface pole figure is shown in FIG. The scales on the vertical and horizontal axes of the pole figure each indicate an angle of 10 degrees from the normal direction. The pole figure of the alloy containing only 3.0% Cu is shown in FIG. 3, and the point showing the maximum is slightly inclined from the center of the figure, but the deviation is within 10 degrees. On the other hand, in the CZ3015 alloy shown in FIG. 10, the inclination is about 15 degrees, and the (0001) plane has a greater inclination from the normal direction of the surface than in the case of the alloy containing Cu alone. FIG. 11 shows the results of investigating the relationship between the redox current density and potential of this CZ3015 alloy. The potential difference between the oxidation current density of 900 μAcm −2 and the reduction current density of 180 μAcm −2 at 120 μAh of the alloy containing 3.0% Cu alone can be read as 0.33V from FIG. On the other hand, the potential difference of the C3015 alloy, which is made by adding Zn to Cu, can be read as 0.25 V from Figure 11, and by adding Zn and tilting the (0001) plane from the normal direction of the surface, the performance as an electrochemical device is improved. I can see that it is improving.
As can be seen from FIG. 11, this alloy maintains a flat potential up to a high redox current density and suppresses overvoltage. This suggests that stable charging and discharging is possible even when high current is applied.
（実施例３）Ｃｕ－Ｃａ合金（ＣＸ合金；ＸはＣａを表す。）
ＣＸ３００５およびＣＸ３０１０の酸化還元電位を図１２および図１３に示す。ＣＸ３００５（Ｃａ０．５％添加）では還元電流密度１８０μＡｃｍ-2でやや不安定な挙動を示すが１２０μＡｃｍ-2以下では高い電位が維持できている。高い還元電流密度までフラット電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 3) Cu-Ca alloy (CX alloy; X represents Ca)
The redox potentials of CX3005 and CX3010 are shown in FIGS. 12 and 13. CX3005 (with 0.5% Ca added) exhibits somewhat unstable behavior at a reduction current density of 180 μAcm −2 , but a high potential is maintained below 120 μAcm −2 . Results have been obtained in which a flat potential is maintained up to a high reduction current density and overvoltage is also suppressed. This suggests that stable charging and discharging is possible even when high current is applied.
（実施例４）Ｃｕ－Ｚｎ－Ｃａ合金（ＣＺＸ合金）
Ｃｕ添加の効果に加えて、（０００１）面を表面の法線方向から傾けた効果を調べるもう一つの例として、ＣＺＸ３０１５０１の（０００２）面極点図および酸化還元電流密度と電位の関係を調べた。図４に（０００２）面極点図を、図１４に酸化還元電流密度と電位の関係を示す。図１４から、ＣＺＸ３０１５０１合金では、表面の法線方向に（０００１）面の極大値はなく、板の圧延方向（図では上下方向）とほぼ直角な方向に２箇所極大を持ち、（０００１）面が表面と傾斜して存在していることわかる。この合金の酸化還元電流密度と電位の関係を示す図１４から１２０μＡｈにおける酸化電流密度９００μＡｃｍ-2と還元電流密度１８０μＡｃｍ-2との電位差を読み取ると、０．２０Ｖとなり、Ｃｕのみ３．０％を含有するＣ３０合金の結果である０．３３Ｖと比較して小さな値となり、（０００１）面と表面を傾斜させて存在させることにより、より性能の良い電気化学デバイスが得られることがわかる。
同じ成分系として、ＣＺＸ３０１５０５およびＣＺＸ３０１５１０の酸化還元電位を図１５、および図１６に示す。Ｃａの割合が高くなると、還元過電圧が増大する傾向にあるが、一般的なＡｌ－Ｚｎ合金より著しく高い電流を印加してもフラット電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 4) Cu-Zn-Ca alloy (CZX alloy)
In addition to the effect of Cu addition, as another example of investigating the effect of tilting the (0001) plane from the normal direction of the surface, we investigated the (0002) plane pole figure of CZX301501 and the relationship between redox current density and potential. . FIG. 4 shows a (0002) plane pole figure, and FIG. 14 shows the relationship between redox current density and potential. From Figure 14, it can be seen that in the CZX301501 alloy, there is no local maximum on the (0001) plane in the normal direction of the surface, but there are two local maxima in a direction almost perpendicular to the rolling direction of the plate (vertical direction in the figure), It can be seen that the surface is inclined to the surface. When reading the potential difference between the oxidation current density of 900 μAcm -2 and the reduction current density of 180 μAcm -2 at 120 μAh from FIG. 14, which shows the relationship between the redox current density and potential of this alloy, it is 0.20 V, and only Cu is 3.0%. This value is smaller than 0.33V, which is the result of the containing C30 alloy, and it can be seen that an electrochemical device with better performance can be obtained by making the (0001) plane and the surface inclined.
The redox potentials of CZX301505 and CZX301510 are shown in FIG. 15 and FIG. 16 as the same component system. As the proportion of Ca increases, the reduction overvoltage tends to increase, but even when a significantly higher current is applied than in general Al-Zn alloys, a flat potential is maintained and overvoltage is suppressed. . This suggests that stable charging and discharging is possible even when high current is applied.
（実施例５）Ｃｕ－Ｓｎ合金（ＣＴ合金）
周期表４Ｂ族元素の代表としてＳｎを選び、Ｓｎを添加した合金を作成して測定を実施した。
ＣＴ３０１５の酸化還元電位を図１７に示す。高い還元電流密度までフラット電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 5) Cu-Sn alloy (CT alloy)
Sn was selected as a representative of Group 4B elements of the periodic table, and an alloy to which Sn was added was prepared and measured.
The redox potential of CT3015 is shown in FIG. Results have been obtained in which a flat potential is maintained up to a high reduction current density and overvoltage is also suppressed. This suggests that stable charging and discharging is possible even when high current is applied.
（実施例６）Ｃｕ－Ｚｎ－Ｓｉ－合金（ＣＳ合金）
ＣＺＳＸ３０１５１００１の酸化還元電位を図１８に示す。高い還元電流密度までフラット電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 6) Cu-Zn-Si-alloy (CS alloy)
The redox potential of CZSX30151001 is shown in FIG. Results have been obtained in which a flat potential is maintained up to a high reduction current density and overvoltage is also suppressed. This suggests that stable charging and discharging is possible even when high current is applied.
（実施例７）Ｃｕ－Ｍｍ合金（ＣＥ合金）
ＣＺＥＸ３０１５１００１の酸化還元電位を図１９に示す。高い還元電流密度までフラット電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 7) Cu-Mm alloy (CE alloy)
The redox potential of CZEX30151001 is shown in FIG. Results have been obtained in which a flat potential is maintained up to a high reduction current density and overvoltage is also suppressed. This suggests that stable charging and discharging is possible even when high current is applied.
（実施例８）Ｃｕ－Ｍｎ合金（ＣＭ合金）
ＭｎおよびＺｒ添加の一例として、ＣｕにさらにＭｎを添加したＣＭ５００５合金の酸化還元電位を図２０に示す。Ｃｕのみを含有するＣ３０、Ｃ１００合金の結果である、図７および図８と比較して、Ｍｎを含有することにより酸化還元電流密度と電位の関係がより高いフラット性を示している。このようにＭｎを添加するとＣｕ単独よりもよりフラットな電位が維持され、過電圧も抑制される結果が得られている。これは高電流を印加しても安定して充放電できることを示唆している。
(Example 8) Cu-Mn alloy (CM alloy)
As an example of Mn and Zr addition, FIG. 20 shows the oxidation-reduction potential of a CM5005 alloy in which Mn is further added to Cu. Compared to FIGS. 7 and 8, which are the results of C30 and C100 alloys containing only Cu, the relationship between redox current density and potential shows a higher flatness due to the inclusion of Mn. When Mn is added in this manner, a flatter potential is maintained than when Cu alone is used, and overvoltage is also suppressed. This suggests that stable charging and discharging is possible even when high current is applied.
前記比較例、実施例の化学成分と電気化学デバイスとしての性能をまとめて表１に示す。表１中で電気化学デバイスとしての性能欄に○が記載されているものは還元電流密度９０μＡｃｍ-2までフラットな電位が維持され（Ｃａｐａｃｉｔｙが２０μＡｈと１２０μＡｈのときの電圧を比較して、その差が０．１Ｖ以内）、電気化学デバイスの電極材として優れていることを表している。×はその性能が劣ることを表している。 The chemical components and performance as an electrochemical device of the Comparative Examples and Examples are summarized in Table 1. In Table 1, devices marked with a circle in the performance column as electrochemical devices maintain a flat potential up to a reduction current density of 90 μAcm -2 (comparing the voltages when the capacity is 20 μAh and 120 μAh, the difference is (within 0.1 V), indicating that it is excellent as an electrode material for electrochemical devices. × indicates that the performance is inferior.
表１
本発明の電極材は、電気化学デバイスすなわち１次電池、２次電池、およびキャパシタなどに適用することができる。本発明は、マグネシウムを用いているため、安全でかつ資源の確保も容易であり、工業的かつ社会的に極めて有効である。 The electrode material of the present invention can be applied to electrochemical devices, ie, primary batteries, secondary batteries, capacitors, and the like. Since the present invention uses magnesium, it is safe and easy to secure resources, and is extremely effective industrially and socially.
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| JP2014192009A (en) | 2013-03-27 | 2014-10-06 | Honda Foundry Co Ltd | Negative pole for secondary battery using magnesium alloy and manufacturing method thereof |
| WO2018012360A1 (en) | 2016-07-13 | 2018-01-18 | Canon Kabushiki Kaisha | Continuum robot, modification method of kinematic model of continuum robot, and control method of continuum robot |
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| JP2014192009A (en) | 2013-03-27 | 2014-10-06 | Honda Foundry Co Ltd | Negative pole for secondary battery using magnesium alloy and manufacturing method thereof |
| WO2018012360A1 (en) | 2016-07-13 | 2018-01-18 | Canon Kabushiki Kaisha | Continuum robot, modification method of kinematic model of continuum robot, and control method of continuum robot |
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