JP7141809B2 - Anode Materials, Anodes, and Iron-Air Batteries - Google Patents
Anode Materials, Anodes, and Iron-Air Batteries Download PDFInfo
- Publication number
- JP7141809B2 JP7141809B2 JP2019512562A JP2019512562A JP7141809B2 JP 7141809 B2 JP7141809 B2 JP 7141809B2 JP 2019512562 A JP2019512562 A JP 2019512562A JP 2019512562 A JP2019512562 A JP 2019512562A JP 7141809 B2 JP7141809 B2 JP 7141809B2
- Authority
- JP
- Japan
- Prior art keywords
- iron
- mass
- negative electrode
- surface modifier
- substrate particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M12/00—Hybrid cells; Manufacture thereof
- H01M12/08—Hybrid cells; Manufacture thereof composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
-
- 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
Description
本発明は、鉄空気電池用の負極材料、並びに該負極材料を用いた負極及び鉄空気電池に関する。 The present invention relates to a negative electrode material for an iron-air battery, and a negative electrode and iron-air battery using the negative electrode material.
金属空気電池は空気極の活物質として大気中の酸素を利用できることから、空気極の反応物質をゼロと考え、電池の大部分を負極の反応物質で構成できるので、比較的容易に高エネルギー密度化が可能である。そのため、リチウムイオン電池に代わる車載用二次電池等としての利用が期待されている。金属空気電池の負極には、亜鉛、リチウム、マグネシウム、アルミニウム、鉄等の金属が用いられる。金属空気電池の空気極には、カーボン材料や、酸化物触媒、貴金属触媒等で構成された触媒層が用いられる。 Since the metal-air battery can use atmospheric oxygen as the active material for the air electrode, it is possible to assume that the reactant of the air electrode is zero, and the majority of the battery can be composed of the reactant of the negative electrode, making it relatively easy to achieve high energy density. is possible. Therefore, it is expected to be used as an in-vehicle secondary battery or the like in place of a lithium-ion battery. Metals such as zinc, lithium, magnesium, aluminum, and iron are used for the negative electrodes of metal-air batteries. A catalyst layer composed of a carbon material, an oxide catalyst, a noble metal catalyst, or the like is used for the air electrode of a metal-air battery.
亜鉛空気電池等の多くの金属空気電池では、充電時に負極上にデンドライト状結晶が析出し、電極間で短絡が発生しやすくなるという問題がある。これに対し、鉄空気電池の負極ではデンドライト状結晶が形成されにくく、そのため鉄空気電池は比較的サイクル特性に優れている。また、リチウム空気電池やアルミニウム空気電池等と比較すると、鉄空気電池の負極は耐腐食性が高い。更に、鉄は資源が豊富であり、安価であり、毒性が低く、容易に再利用でき、環境に優しいという利点を有する。このような理由から、近年、鉄空気電池が関心を集めている。 Many metal-air batteries, such as zinc-air batteries, have the problem that dendrite-like crystals are deposited on the negative electrode during charging, making short circuits between electrodes more likely to occur. In contrast, dendrite-like crystals are less likely to be formed in the negative electrode of iron-air batteries, and therefore the iron-air batteries have relatively excellent cycle characteristics. In addition, compared to lithium-air batteries, aluminum-air batteries, and the like, the negative electrode of iron-air batteries is highly resistant to corrosion. In addition, iron has the advantages of abundant resources, low cost, low toxicity, easy recycling, and environmental friendliness. For these reasons, interest in iron-air batteries has increased in recent years.
通常、鉄空気電池の負極は、金属鉄又は酸化鉄を含む鉄基材からなる。鉄空気電池の充放電過程においては、鉄基材の表面領域のみが反応すると考えられている（非特許文献１）。そのため、鉄空気電池は大容量化が困難であるという問題を有する。 The negative electrode of an iron-air battery typically consists of an iron substrate, including metallic iron or iron oxide. It is believed that only the surface region of the iron substrate reacts during the charging and discharging process of the iron-air battery (Non-Patent Document 1). Therefore, the iron-air battery has a problem that it is difficult to increase the capacity.
そこで、反応に寄与する鉄の量（鉄利用率）を改善する方法が検討されており、カーボン材料を用いて負極の導電性を改善する方法が知られている。例えば、Ｆｅ３Ｏ４ナノ粒子をカーボンナノ繊維の表面に分布させる方法が提案されている（非特許文献２）。Therefore, methods for improving the amount of iron that contributes to the reaction (iron utilization rate) have been investigated, and a method for improving the conductivity of the negative electrode using a carbon material is known. For example, a method of distributing Fe 3 O 4 nanoparticles on the surface of carbon nanofibers has been proposed (Non-Patent Document 2).
しかしながら、上記カーボン材料を用いる方法では、得られる負極が非常に嵩高いため、鉄空気電池の容量密度が低下する。鉄空気電池を実用化するためには、鉄基材の充填密度を損なわずに導電性を向上させ、放電特性を更に改善することが必要とされている。 However, in the method using the above carbon material, the negative electrode obtained is very bulky, so the capacity density of the iron-air battery is lowered. In order to put the iron-air battery into practical use, it is necessary to improve the conductivity and further improve the discharge characteristics without impairing the packing density of the iron base material.
本発明の目的は、鉄空気電池の負極に使用した際に放電特性を改善し得る負極材料を提供することである。 An object of the present invention is to provide a negative electrode material capable of improving discharge characteristics when used as a negative electrode of an iron-air battery.
本発明の他の目的は、鉄空気電池に使用した際に放電特性を改善し得る負極を提供することである。 Another object of the present invention is to provide a negative electrode capable of improving discharge characteristics when used in an iron-air battery.
本発明の更なる目的は、改善された放電特性を示す鉄空気電池を提供することである。 A further object of the present invention is to provide an iron-air battery that exhibits improved discharge characteristics.
本発明者は、上記課題を解決するべく鋭意検討した結果、鉄基材粒子の表面に特定の銅系表面修飾物質を特定量だけ付着させてなる負極材料を使用することによって、放電特性が改善された鉄空気電池が得られることを見出し、本発明を完成するに至った。 As a result of intensive studies aimed at solving the above problems, the present inventors have found that discharge characteristics are improved by using a negative electrode material in which a specific amount of a specific copper-based surface modifier is attached to the surface of iron-based particles. The inventors have found that an iron-air battery with a high temperature resistance can be obtained, and have completed the present invention.
本発明の負極材料は、鉄空気電池に用いられ、基材粒子と該基材粒子の表面に付着した表面修飾物質とからなり、前記基材粒子が３０原子％以上１００原子％以下のＦｅを含み、前記表面修飾物質が２０原子％以上１００原子％以下のＣｕを含み、１００質量％の前記基材粒子に対する前記表面修飾物質の質量比が０．００１質量％以上３０質量％未満である。 The negative electrode material of the present invention is used in an iron-air battery, and comprises substrate particles and a surface modifier attached to the surface of the substrate particles, and the substrate particles contain 30 atomic % or more and 100 atomic % or less of Fe. The surface modifier contains 20 atomic % or more and 100 atomic % or less of Cu, and the mass ratio of the surface modifier to 100 mass % of the substrate particles is 0.001 mass % or more and less than 30 mass %.
本発明の負極は上記本発明の負極材料を含み、本発明の鉄空気電池は該負極を有する。 The negative electrode of the present invention comprises the negative electrode material of the present invention, and the iron-air battery of the present invention has the negative electrode.
本発明の負極材料では特定量の表面修飾物質が基材粒子の表面に付着しており、そのため該負極材料を用いた本発明の鉄空気電池は改善された放電特性を示す。より詳しくは、本発明の鉄空気電池は、十分な電圧と大きな放電容量の両方を達成し得る。 In the negative electrode material of the present invention, a specific amount of surface modifier is attached to the surface of the substrate particles, so that the iron-air battery of the present invention using the negative electrode material exhibits improved discharge characteristics. More specifically, the iron-air battery of the present invention can achieve both sufficient voltage and large discharge capacity.
本発明の負極材料は、基材粒子と該基材粒子の表面に付着した表面修飾物質とからなり、鉄空気電池に用いられる。 The negative electrode material of the present invention is composed of substrate particles and a surface modifier adhered to the surfaces of the substrate particles, and is used in iron-air batteries.
基材粒子は主成分（鉄基材）として鉄単体（金属鉄）、酸化鉄、又はこれらの混合物を含有する。酸化鉄の例としてはＦｅ２Ｏ３、Ｆｅ３Ｏ４等が挙げられる。本発明の負極材料を鉄空気電池に用いた際に高い容量密度を得るためには、基材粒子は比重が大きく、微細であり、表面積が大きいことが好ましい。比重の観点からは金属鉄が好ましいが、金属鉄を微細に調製することは難しく、酸化鉄の微細粒子を調製することでより大きな放電容量が得られる場合もある。The substrate particles contain iron simple substance (metallic iron), iron oxide, or a mixture thereof as a main component (iron substrate). Examples of iron oxides include Fe2O3 , Fe3O4 , and the like. In order to obtain a high capacity density when the negative electrode material of the present invention is used in an iron-air battery, it is preferable that the substrate particles have a large specific gravity, are fine, and have a large surface area. Metallic iron is preferable from the viewpoint of specific gravity, but it is difficult to finely prepare metallic iron, and a larger discharge capacity may be obtained by preparing fine particles of iron oxide.
基材粒子はその特性に大きな悪影響を与えない範囲の量で不純物を含んでいてもよい。本発明において、「不純物」は、意図的に添加したわけではないが負極材料に混入した成分であり、負極材料中で何ら効果を示さないか、或いは効果が不明な成分を意味する。基材粒子の不純物としては、Ｎａ、Ｃａ、Ｎｂ、Ｃｒ、Ｍｎ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ａｌ、Ｇａ、Ｓｉ、Ｐ、Ｓ、Ｃｌ、希土類元素（Ｐｒ、Ｎｄ、Ｄｙ等）等が挙げられる。希土類酸化物は鉄よりも高い還元電位を示すため、鉄空気電池を充電しても不活性なままである。従って、本発明では希土類元素を不純物として扱う。 The substrate particles may contain impurities in amounts that do not significantly adversely affect their properties. In the present invention, the term "impurity" means a component that is not intentionally added but mixed into the negative electrode material, and means a component that does not exhibit any effect in the negative electrode material or whose effect is unknown. Impurities in the substrate particles include Na, Ca, Nb, Cr, Mn, Co, Ni, Cu, Zn, Al, Ga, Si, P, S, Cl, and rare earth elements (Pr, Nd, Dy, etc.). mentioned. Rare earth oxides exhibit a higher reduction potential than iron and therefore remain inert when iron-air batteries are charged. Therefore, in the present invention, rare earth elements are treated as impurities.
基材粒子全体に対する主成分の質量比は、通常は９５質量％以上であり、好ましくは１００質量％である。基材粒子全体に対する不純物の質量比は、好ましくは０質量％であるが、５質量％以下であれば本発明の放電特性改善効果が十分に得られる。これら質量比はＸ線回折法、高周波誘導結合プラズマ（ＩＣＰ）発光分光分析法等によって測定できる。 The mass ratio of the main component to the entire substrate particles is usually 95% by mass or more, preferably 100% by mass. The mass ratio of the impurities to the entire substrate particles is preferably 0% by mass, but if it is 5% by mass or less, the discharge characteristics improving effect of the present invention can be sufficiently obtained. These mass ratios can be measured by X-ray diffraction, high frequency inductively coupled plasma (ICP) emission spectrometry, or the like.
基材粒子の全構成原子に対するＦｅの原子比は、３０原子％以上１００原子％以下である。例えば、基材粒子が金属鉄のみからなる場合、当該原子比は１００原子％である。基材粒子がＦｅ２Ｏ３のみからなる場合、当該原子比は４０原子％である。この原子比はＸ線回折法、ＩＣＰ発光分光分析法等によって測定できる。The atomic ratio of Fe to all constituent atoms of the substrate particles is 30 atomic % or more and 100 atomic % or less. For example, when the substrate particles consist only of metallic iron, the atomic ratio is 100 atomic %. When the substrate particles consist only of Fe 2 O 3 , the atomic ratio is 40 atomic %. This atomic ratio can be measured by X-ray diffraction, ICP emission spectrometry, or the like.
上述のとおり、基材粒子は微細であることが好ましい。具体的には、基材粒子のＤ５０粒径は５μｍ以下であるのが好ましい。負極材料を電池ケース等に充填する場合は、基材粒子が過剰に微細であると充填性（充填密度）が低下し、容量密度が向上しないことがある。従って、このような場合は、基材粒子のＤ５０粒径を０．１μｍ以上とするのが好ましい。このＤ５０粒径は粒度分布計等によって測定できる。 As mentioned above, the substrate particles are preferably fine. Specifically, the D50 particle size of the substrate particles is preferably 5 μm or less. When the negative electrode material is filled into a battery case or the like, if the substrate particles are excessively fine, the filling property (filling density) is lowered, and the capacity density may not be improved. Therefore, in such a case, the D50 particle size of the substrate particles is preferably 0.1 μm or more. This D50 particle size can be measured by a particle size distribution meter or the like.
上述のとおり、基材粒子は大きな表面積を有することが好ましい。具体的には、基材粒子のＢＥＴ比表面積は、好ましくは０．１ｍ２／ｇ以上、より好ましくは０．３ｍ２／ｇ以上である。一方、負極材料の充填性、ひいては容積あたりの電池容量を向上させる観点からは、基材粒子のＢＥＴ比表面積は、好ましくは７０ｍ２／ｇ以下、より好ましくは６５ｍ２／ｇ以下である。このＢＥＴ比表面積は、例えばＭａｃｓｏｒｂ ＨＭ－１２１０（ＭＯＵＮＴＥＣＨ社製）等を用いて、窒素ガス吸着ＢＥＴ法等によって測定できる。As noted above, it is preferred that the substrate particles have a large surface area. Specifically, the BET specific surface area of the substrate particles is preferably 0.1 m 2 /g or more, more preferably 0.3 m 2 /g or more. On the other hand, the BET specific surface area of the substrate particles is preferably 70 m 2 /g or less, more preferably 65 m 2 /g or less, from the viewpoint of improving the filling property of the negative electrode material and thus the battery capacity per unit volume. This BET specific surface area can be measured by a nitrogen gas adsorption BET method or the like using, for example, Macsorb HM-1210 (manufactured by MOUNTECH).
基材粒子の形状は球状や八面体状等であってよい。基材粒子はそれぞれが独立した粒子であってもよく、一部が焼結により繋がっていてもよく、一部が二次粒子として凝集していてもよい。 The shape of the substrate particles may be spherical, octahedral, or the like. The substrate particles may be independent particles, partly connected by sintering, or partly aggregated as secondary particles.
基材粒子は尿素を用いた均一沈殿法等によって調製できる。基材粒子は市販品であってもよく、その例としては、ＢＡＳＦ製カルボニル鉄ＳＱグレード（Ｄ５０＝４．０μｍ）、和光純薬工業株式会社製Ｆｅ２Ｏ３粒子（Ｄ５０＝１．９μｍ）等が挙げられる。また、本発明では、例えば希土類磁石のリサイクル工程等で生じた残渣を基材粒子として用いることも可能である。通常このような残渣は希土類磁石に由来する元素を含有するが、その量が上記不純物の質量比の範囲（５質量％以下）内であれば、本発明の効果が十分に得られる。The substrate particles can be prepared by a uniform precipitation method using urea or the like. The substrate particles may be commercially available products, examples of which include BASF carbonyl iron SQ grade (D50 = 4.0 µm), Wako Pure Chemical Industries, Ltd. Fe 2 O 3 particles (D50 = 1.9 µm). etc. Further, in the present invention, it is possible to use, as the substrate particles, residues generated in, for example, the recycling process of rare earth magnets. Such residues usually contain elements derived from rare earth magnets, and the effects of the present invention can be sufficiently obtained as long as the amount is within the range of the mass ratio of impurities (5% by mass or less).
表面修飾物質は主成分として銅単体（金属銅）、銅化合物、又はこれらの混合物を含有する。銅化合物の例としてはＣｕＯ、Ｃｕ２Ｏ、Ｃｕ（ＯＨ）２等が挙げられる。負極の導電性を向上させるためには、表面修飾物質の主成分はＣｕであることが好ましい。しかしながら、基材粒子に付着させた直後、充電前、或いは放電後の時点では、表面修飾物質の主成分はＣｕＯ、Ｃｕ２Ｏ、又はＣｕ（ＯＨ）２を含んでいてもよい。鉄空気電池を充電すると、ＣｕＯ、Ｃｕ２Ｏ、及びＣｕ（ＯＨ）２はＣｕの状態まで還元される。The surface modifier contains copper as a main component (metallic copper), a copper compound, or a mixture thereof. Examples of copper compounds include CuO, Cu2O, Cu (OH)2 , and the like. In order to improve the conductivity of the negative electrode, the main component of the surface modifier is preferably Cu. However, the main component of the surface modifier may contain CuO, Cu 2 O, or Cu(OH) 2 immediately after being attached to the substrate particles, before charging, or after discharging. Upon charging the iron-air battery, CuO, Cu2O and Cu(OH)2 are reduced to the Cu state.
表面修飾物質はその特性に大きな悪影響を与えない範囲の量で不純物を含んでいてもよい。表面修飾物質の不純物は、その前駆体又は中和剤に由来する元素であってよく、その例としてはＬｉ、Ｎａ、Ｋ、Ｓ等が挙げられる。 The surface modifier may contain impurities in an amount that does not adversely affect its properties. Impurities in the surface modifier may be elements derived from its precursors or neutralizers, examples of which include Li, Na, K, S, and the like.
表面修飾物質全体に対する主成分の質量比は、通常は９５質量％以上であり、好ましくは１００質量％である。表面修飾物質全体に対する不純物の質量比は、好ましくは０質量％であるが、５質量％以下であれば本発明の放電特性改善効果が十分に得られる。これら質量比はＸ線回折法、ＩＣＰ発光分光分析法等によって測定できる。 The mass ratio of the main component to the entire surface modifier is usually 95% by mass or more, preferably 100% by mass. The mass ratio of impurities to the entire surface modifier is preferably 0% by mass, but if it is 5% by mass or less, the discharge characteristics improving effect of the present invention can be sufficiently obtained. These mass ratios can be measured by an X-ray diffraction method, an ICP emission spectroscopic analysis method, or the like.
表面修飾物質の全構成原子に対するＣｕの原子比は、２０原子％以上１００原子％以下であり、好ましくは５０原子％以上１００原子％以下である。すなわち、Ｃｕ（ＯＨ）２は比重が小さいため、負極材料の充填密度の観点からはＣｕ、ＣｕＯ、及びＣｕ２Ｏのほうが好ましい。この原子比は、Ｘ線回折により同定された相やエネルギー分散型Ｘ線分析装置（ＥＤＳ）等を用いて測定できる。The atomic ratio of Cu to all constituent atoms of the surface modifier is 20 atomic % or more and 100 atomic % or less, preferably 50 atomic % or more and 100 atomic % or less. That is, since Cu(OH) 2 has a small specific gravity, Cu, CuO, and Cu 2 O are preferable from the viewpoint of the packing density of the negative electrode material. This atomic ratio can be measured using a phase identified by X-ray diffraction, an energy dispersive X-ray spectrometer (EDS), or the like.
表面修飾物質は粒状であってよい。表面修飾物質の平均粒径は、好ましくは１０ｎｍ以上５００ｎｍ以下であり、より好ましくは２０ｎｍ以上２００ｎｍ以下である。すなわち、本発明で用いる表面修飾物質は非常に微細な粒子であり得る。表面修飾物質の平均粒径は走査型電子顕微鏡（ＳＥＭ）観察等によって測定できる。 The surface modifier may be particulate. The average particle diameter of the surface modifier is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 200 nm or less. That is, the surface modifier used in the present invention can be very fine particles. The average particle size of the surface modifier can be measured by scanning electron microscope (SEM) observation or the like.
本発明の負極材料において、表面修飾物質は基材粒子の表面に付着している。表面修飾物質は基材粒子の表面上で均一に分散していることが好ましく、基材粒子の表面全て又は一部を被覆していてもよい。なお、本発明において「表面修飾物質が基材粒子の表面に付着している」とは、表面修飾物質が該表面に接触して保持されていることを意味する。表面修飾物質が該表面に物理吸着及び／又は化学結合していてもよく、また表面修飾物質と基材粒子がその接触界面の一部又は全体で固溶体を形成していてもよい。ただし、本発明の負極材料は、後述する工程（ａ）～（ｃ）を含む製造方法によって達成される特定の付着状態を有する。この特定の付着状態は、鉄基材粒子と銅粒子とを単に混ぜて得られる混合物では得られない。本発明の特定の付着状態と該混合物等における界面状態との違いを数値範囲により特定することは困難であるが、後述する実施例に示すように、該混合物を鉄空気電池に用いると放電特性が低下する。 In the negative electrode material of the present invention, the surface modifier adheres to the surface of the substrate particles. The surface modifier is preferably dispersed uniformly on the surface of the substrate particles, and may cover all or part of the surfaces of the substrate particles. In the present invention, "a surface modifying substance adheres to the surface of the substrate particles" means that the surface modifying substance is held in contact with the surface. The surface modifying substance may be physically adsorbed and/or chemically bonded to the surface, and the surface modifying substance and substrate particles may form a solid solution at part or all of their contact interface. However, the negative electrode material of the present invention has a specific state of adhesion achieved by a manufacturing method including steps (a) to (c) described below. This particular state of adhesion cannot be obtained with a mixture obtained by simply mixing iron-based particles and copper particles. Although it is difficult to specify the difference between the specific adhesion state of the present invention and the interface state in the mixture or the like by a numerical range, as shown in the examples described later, when the mixture is used in an iron-air battery, the discharge characteristics decreases.
また、鉄基材粒子と銅粒子とを単に混合する場合、上述した平均粒径５００ｎｍ以下の微細な銅粒子を工業的に製造することは技術的に困難であり、また高コストである。更に、この場合、微細な銅粒子を鉄基材粒子上に均一に分散させ付着させることは実質的に不可能である。微細な酸化銅粒子として古河ケミカルズ株式会社製ＦＲＣ－Ｎ１０が市販されているが、顕微鏡観察によってこの粒子は二次凝集していることが確認できる。二次凝集粒子を基材粒子上に均一に分散させ付着させるには、非常に煩雑な工程が必要であると考えられる。本発明では、後述する工程（ａ）～（ｃ）を含む製造方法によって、微細な表面修飾物質粒子を基材粒子上に容易に付着させることができる。 Further, when iron base particles and copper particles are simply mixed, it is technically difficult and expensive to industrially produce fine copper particles having an average particle size of 500 nm or less. Furthermore, in this case, it is virtually impossible to uniformly disperse and adhere fine copper particles onto the iron substrate particles. FRC-N10 manufactured by Furukawa Chemicals Co., Ltd. is commercially available as fine copper oxide particles, and it can be confirmed by microscopic observation that these particles are secondary aggregates. It is considered that a very complicated process is required to uniformly disperse and adhere the secondary aggregated particles on the substrate particles. In the present invention, the production method including steps (a) to (c), which will be described later, allows the fine surface modifier particles to be easily adhered onto the substrate particles.
本発明の負極材料において、１００質量％の基材粒子に対する表面修飾物質の質量比は、０．００１質量％以上３０質量％未満である。表面修飾物質の質量比が低すぎる場合は、十分な導電性改善効果が得られない。一方、表面修飾物質の質量比が高すぎる場合は、基材粒子の充填量が減少するため鉄空気電池の電圧が低下する。表面修飾物質の質量比は、好ましくは０．００５質量％以上、より好ましくは０．３質量％以上である。また、該質量比は好ましくは２５質量％以下である。この含有割合はＩＣＰ発光分光分析法等によって測定できる。 In the negative electrode material of the present invention, the mass ratio of the surface modifier to 100% by mass of the substrate particles is 0.001% by mass or more and less than 30% by mass. If the mass ratio of the surface modifier is too low, a sufficient conductivity improving effect cannot be obtained. On the other hand, if the mass ratio of the surface-modifying substance is too high, the amount of substrate particles to be filled is reduced, resulting in a decrease in voltage of the iron-air battery. The mass ratio of the surface modifier is preferably 0.005% by mass or more, more preferably 0.3% by mass or more. Moreover, the mass ratio is preferably 25 mass % or less. This content ratio can be measured by ICP emission spectrometry or the like.
本発明の負極材料は、（ａ）基材粒子、表面修飾物質の前駆体、及び中和剤を溶媒中で撹拌し、スラリーを調製する工程、（ｂ）得られたスラリーをろ過してケーキを得る工程、及び（ｃ）ケーキを焼成する工程を含む方法によって製造できる。 The negative electrode material of the present invention is produced by (a) preparing a slurry by stirring base particles, a precursor of a surface modifier, and a neutralizing agent in a solvent, and (b) filtering the obtained slurry to obtain a cake. and (c) baking a cake.
工程（ａ）において、例えば、まず溶媒に基材粒子を加え、更に中和剤を加え、これに表面修飾物質前駆体の溶液を滴下して中和反応を行うことで、表面修飾物質を形成して基材粒子の表面に付着させることができる。このとき、表面修飾物質前駆体溶液を滴下した後のｐＨが４．０以上となるように各成分の量を調整する。或いは、溶媒に基材粒子を加え、アルカリ性の中和剤溶液と酸性の表面修飾物質前駆体溶液とを、ｐＨを４．０以上に調整しながら同時に滴下し、中和反応を行ってもよい。表面修飾物質の量が多い場合（例えば、１００質量％の基材粒子に対し５質量％以上の表面修飾物質を付着させる場合）、多量の中和剤を溶解させることが難しいため、中和剤と表面修飾物質前駆体とを同時に添加することが好ましい。 In the step (a), for example, the substrate particles are first added to the solvent, the neutralizing agent is further added, and the solution of the precursor of the surface modifying substance is added dropwise thereto to carry out a neutralization reaction, thereby forming the surface modifying substance. can be adhered to the surface of the substrate particles. At this time, the amount of each component is adjusted so that the pH after dropping the surface modifier precursor solution is 4.0 or higher. Alternatively, the substrate particles may be added to the solvent, and an alkaline neutralizer solution and an acidic surface modifier precursor solution may be added dropwise at the same time while adjusting the pH to 4.0 or higher to carry out a neutralization reaction. . When the amount of the surface modifier is large (for example, when 5% by mass or more of the surface modifier is attached to 100% by mass of the base particles), it is difficult to dissolve a large amount of the neutralizer. and the surface modifier precursor are preferably added at the same time.
工程（ａ）において、表面修飾物質前駆体としては硫酸銅、硝酸銅、これらの水和物等を用いることができる。中和剤としては水酸化リチウム、水酸化ナトリウム、水酸化カリウム等を用いることができる。溶媒としては水、エタノール等を用いることができる。表面修飾物質前駆体溶液の添加速度、中和剤溶液の添加速度、溶媒の量、撹拌方法等は、基材粒子を均一に撹拌でき、表面修飾物質を均一に分散できれば特に限定されない。撹拌温度は溶媒が蒸発しない温度であれば特に限定されない。 In step (a), copper sulfate, copper nitrate, hydrates thereof, and the like can be used as the surface modifier precursor. Lithium hydroxide, sodium hydroxide, potassium hydroxide and the like can be used as the neutralizing agent. Water, ethanol, or the like can be used as the solvent. The addition speed of the surface modifier precursor solution, the addition speed of the neutralizer solution, the amount of the solvent, the stirring method, etc. are not particularly limited as long as the substrate particles can be uniformly stirred and the surface modifier can be uniformly dispersed. The stirring temperature is not particularly limited as long as the temperature does not evaporate the solvent.
工程（ｂ）において、スラリーをろ過した後、ケーキを洗浄するのが好ましい。ろ過及び洗浄には、吸引ろ過器、フィルタープレス、遠心分離機等を使用できる。洗浄には水、エタノール等の液体を用いることができる。ろ過後の洗浄が不十分な場合、負極材料に中和剤由来のＬｉ、Ｎａ、Ｋ等が混入する場合がある。通常、洗浄液の導電率を測定することによって、洗浄度合いを確認する。 In step (b), it is preferred to wash the cake after filtering the slurry. A suction filter, filter press, centrifuge, or the like can be used for filtration and washing. A liquid such as water or ethanol can be used for washing. If washing after filtration is insufficient, Li, Na, K, etc. derived from the neutralizing agent may be mixed into the negative electrode material. The degree of cleaning is usually determined by measuring the conductivity of the cleaning liquid.
工程（ｃ）において、ケーキを焼成する温度は、好ましくは１５０℃以上８００℃以下である。この焼成温度が８００℃を超えると、ＣｕとＦｅが過剰に固溶し、Ｃｕが基材粒子内部まで拡散するため、表面修飾による効果が低下する。焼成温度が１５０℃未満であると、表面修飾物質が基材粒子に十分に付着しないため、負極材料の導電性が十分に向上せず、鉄利用率の向上効果が小さくなる。焼成時間は特に限定されないが、２～１０時間程度であってよい。焼成は大気中で行ってよく、電気炉やガス炉等を用いて行ってよい。 In step (c), the temperature for baking the cake is preferably 150°C or higher and 800°C or lower. If the sintering temperature exceeds 800° C., Cu and Fe form an excessive solid solution, and Cu diffuses into the interior of the substrate particles, reducing the effect of surface modification. If the firing temperature is lower than 150° C., the surface modifier will not adhere sufficiently to the substrate particles, so that the conductivity of the negative electrode material will not be sufficiently improved, and the effect of improving the iron utilization rate will be reduced. The firing time is not particularly limited, but may be about 2 to 10 hours. Firing may be performed in the atmosphere, or may be performed using an electric furnace, a gas furnace, or the like.
例えば、表面修飾物質の前駆体として硫酸銅（ＩＩ）五水和物を用いる場合、工程（ａ）において、硫酸銅（ＩＩ）五水和物の少なくとも一部が水酸化銅へと変換され得る。工程（ｃ）では、焼成温度等の条件に依っては、水酸化銅から酸化銅や金属銅が生じることがあり、また水酸化銅の少なくとも一部がそのまま残ることもある。すなわち、この場合、各工程の条件を適宜選択することによって、表面修飾物質として硫酸銅、水酸化銅、酸化銅、及び／又は金属銅を基材粒子表面に付着させることができる。特に、金属銅、酸化銅、又はこれらの組み合わせを基材粒子表面に付着させるのが好ましい。このように、本発明では、表面修飾物質として一種又は複数の物質を基材粒子に付着させてよい。 For example, when copper (II) sulfate pentahydrate is used as the precursor of the surface modifier, in step (a) at least a portion of the copper (II) sulfate pentahydrate can be converted to copper hydroxide. . In the step (c), depending on the conditions such as the sintering temperature, copper oxide or metallic copper may be generated from the copper hydroxide, and at least part of the copper hydroxide may remain as it is. That is, in this case, copper sulfate, copper hydroxide, copper oxide, and/or metallic copper can be attached to the surface of the substrate particles as the surface modifying substance by appropriately selecting the conditions of each step. In particular, it is preferable to attach metallic copper, copper oxide, or a combination thereof to the surface of the substrate particles. Thus, in the present invention, one or more substances may be attached to the substrate particles as surface modifiers.
本発明の鉄空気電池は、通常は負極、空気極、及び電解質を有し、更にセパレータ、集電体、セルケース、開孔部等を有していてもよい。鉄空気電池は負極活物質として鉄及び酸素を利用し、空気極活物質として酸素を利用する。 The iron-air battery of the present invention usually has a negative electrode, an air electrode, and an electrolyte, and may further have a separator, a current collector, a cell case, an aperture, and the like. An iron-air battery utilizes iron and oxygen as negative electrode active materials and oxygen as a cathode active material.
負極は上記本発明の負極材料を含み、更にバインダー、集電体、電極を保持するための芯体、カーボン材料等の導電補助剤等を含んでいてもよい。負極の作製方法は特に限定されないが、例えば本発明の負極材料を圧延加工して得られる。負極の大きさや形状も特に限定されないが、通常、負極の厚みは１０μｍ～５ｍｍ程度であってよい。 The negative electrode contains the negative electrode material of the present invention, and may further contain a binder, a current collector, a core for holding the electrode, a conductive aid such as a carbon material, and the like. Although the method for producing the negative electrode is not particularly limited, it can be obtained, for example, by rolling the negative electrode material of the present invention. Although the size and shape of the negative electrode are not particularly limited, the thickness of the negative electrode may generally be about 10 μm to 5 mm.
空気極は、活物質である酸素に電子を供給するための集電体と、酸素還元反応を促進するための触媒層とを有してよい。集電体は導電性材料を含み、その例としては活性炭、炭素繊維、カーボンブラック、黒鉛等のような炭素質材料や、鉄、銅、ニッケル、アルミニウム等のような金属材料等が挙げられる。触媒層に用いられる触媒の例としては、銀、白金、ルテニウム、パラジウム、カーボン、酸化物等が挙げられる。中でも、資源量の豊富さと反応活性の高さの両立の観点から酸化物系触媒が好ましい。集電体及び触媒層はそれぞれバインダーや撥水材料等を含んでいてもよい。空気極は集電体と触媒層とを別個の構成要素として用意しこれらを積層したものであってよい。或いは、空気極は集電体用の導電性材料と触媒層用の触媒とを混合してなるものであってもよい。即ち、集電体としての機能と触媒層としての機能とを併せ持つ１つの構成要素を空気極として使用してもよい。 The air electrode may have a current collector for supplying electrons to oxygen, which is an active material, and a catalyst layer for promoting the oxygen reduction reaction. The current collector comprises a conductive material, examples of which include carbonaceous materials such as activated carbon, carbon fiber, carbon black, graphite, and metallic materials such as iron, copper, nickel, aluminum, and the like. Examples of catalysts used in the catalyst layer include silver, platinum, ruthenium, palladium, carbon, oxides and the like. Among them, oxide-based catalysts are preferable from the viewpoint of compatibility between abundant resources and high reaction activity. The current collector and catalyst layer may each contain a binder, a water-repellent material, and the like. The air electrode may be obtained by preparing a current collector and a catalyst layer as separate components and laminating them. Alternatively, the air electrode may be formed by mixing a conductive material for the current collector and a catalyst for the catalyst layer. That is, one component having both the function as a current collector and the function as a catalyst layer may be used as the air electrode.
空気極は更に支持体（担体）、撥水層、ガス拡散層等を有していてもよい。支持体は機械的強度を有する材料からなり、その例としてはニッケル等の各種発泡金属、パンチングメタル、マイクロメッシュ等が挙げられる。撥水層は酸素を透過可能であるが水を遮断できる材料からなり、その例としてはポリテトラフルオロエチレン（ＰＴＦＥ）等が挙げられる。ガス拡散層は好ましくは高い多孔性及び高い導電性を有し、その材料の例としてはカーボンペーパー、カーボンクロス等が挙げられる。 The air electrode may further have a support (carrier), a water-repellent layer, a gas diffusion layer, and the like. The support is made of a material having mechanical strength, examples of which include various foam metals such as nickel, punching metals, and micromesh. The water-repellent layer is made of a material that is permeable to oxygen but impervious to water, such as polytetrafluoroethylene (PTFE). The gas diffusion layer preferably has high porosity and high electrical conductivity, and examples of materials thereof include carbon paper, carbon cloth, and the like.
空気極の作製方法は特に限定されないが、例えば、触媒、導電性材料、バインダー、及び溶媒を混合してスラリーを調製し、このスラリーを支持体に塗付し、乾燥して作製できる。溶媒の例としては水や有機溶媒（Ｎ－メチル－２－ピロリドン、エタノール、エチレングリコール等）が挙げられる。空気極の大きさや形状も特に限定されないが、通常、空気極の厚みは２０μｍ～１ｃｍ程度であってよい。 The method for producing the air electrode is not particularly limited, but for example, it can be produced by mixing a catalyst, a conductive material, a binder and a solvent to prepare a slurry, applying this slurry to a support, and drying it. Examples of solvents include water and organic solvents (N-methyl-2-pyrrolidone, ethanol, ethylene glycol, etc.). Although the size and shape of the air electrode are not particularly limited, the thickness of the air electrode may generally be about 20 μm to 1 cm.
電解質は電解質溶液（電解液）の形態で使用してよい。電解液としては、ＫＯＨ、ＮａＣｌ、ＮａＯＨ、ＮａＨＣＯ３、Ｎａ２ＳＯ４、ＨＣｌ、ＨＮＯ３、ＮＨ３等の水溶液が挙げられる。The electrolyte may be used in the form of an electrolyte solution (electrolyte). Examples of electrolytic solutions include aqueous solutions of KOH, NaCl, NaOH, NaHCO 3 , Na 2 SO 4 , HCl, HNO 3 , NH 3 and the like.
通常、セパレータは負極と空気極との間に配置され、両電極間の短絡を防止するとともに、電解質を保持し、イオンを伝導させる役割を有する。セパレータの材料としては、ポリエチレン繊維、ポリプロピレン繊維、ガラス繊維、樹脂不織布、ガラス不織布、濾紙等が挙げられる。 A separator is usually placed between the negative electrode and the air electrode, and has the role of preventing a short circuit between the two electrodes, retaining the electrolyte, and conducting ions. Materials for the separator include polyethylene fiber, polypropylene fiber, glass fiber, resin nonwoven fabric, glass nonwoven fabric, and filter paper.
本発明の鉄空気電池は改善された放電特性を示す。より詳しくは、本発明の鉄空気電池は十分な電圧と大きな放電容量の両方を達成し得る。以下、後述する実施例に示すように鉄空気電池を作製し充放電を３０サイクル行ったとき、３０サイクル中で得られた最大の放電容量を当該鉄空気電池の「最大容量」とし、この最大容量が得られた放電時の平均電圧を「最大容量時電圧」とする。本発明の鉄空気電池は、表面修飾処理を行っていない負極材料を用いた鉄空気電池よりも高い最大容量を示し、且つ０．４Ｖ以上という十分な最大容量時電圧を示す。なお、この最大容量時電圧が０．４Ｖ未満であると、機器を動作させる等の目的で実際に使用する際に、鉄空気電池を多直列化する必要がある。即ち、最大容量時電圧が０．４Ｖ未満の鉄空気電池を実用化しようとすると、煩雑な製造工程が必要となり、コストが増加する。 The iron-air battery of the present invention exhibits improved discharge characteristics. More specifically, the iron-air battery of the present invention can achieve both sufficient voltage and large discharge capacity. Hereinafter, when an iron-air battery is produced and charged and discharged 30 cycles as shown in the examples described later, the maximum discharge capacity obtained during 30 cycles is defined as the "maximum capacity" of the iron-air battery. Let the average voltage at the time of discharge when the capacity is obtained be the "maximum capacity voltage". The iron-air battery of the present invention exhibits a higher maximum capacity than an iron-air battery using a negative electrode material that has not been subjected to surface modification treatment, and exhibits a sufficient voltage at maximum capacity of 0.4 V or more. If the voltage at the maximum capacity is less than 0.4 V, it is necessary to connect multiple iron-air batteries in series when actually using the battery for the purpose of operating a device or the like. That is, if an iron-air battery with a maximum capacity voltage of less than 0.4 V is to be put into practical use, a complicated manufacturing process is required, which increases the cost.
鉄空気電池の製造方法は特に限定されないが、例えば、負極ケース、スペーサー、集電体、負極、セパレータ、空気極、及び空気極ケースをこの順に積層して製造できる。 The method for producing the iron-air battery is not particularly limited, but for example, it can be produced by laminating a negative electrode case, a spacer, a current collector, a negative electrode, a separator, an air electrode, and an air electrode case in this order.
以下、実施例及び比較例により本発明をより詳細に説明するが、本発明はそれらに限定されるものではない。 EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to them.
実施例１
基材粒子の準備
希土類磁石のリサイクル過程で生じた残渣鉄材を基材粒子（Ａ）として用いた。この基材粒子（Ａ）は主に八面体状の形状を有し、Ｆｅ３Ｏ４を主成分として含有していた。Ｘ線回折測定を行ったところ、Ｆｅ３Ｏ４以外の相に起因するピークは確認されなかった。また、ＩＣＰ発光分光分析の結果、基材粒子（Ａ）はＦｅ３Ｏ４に加えてＮｄ、Ｄｙ、Ｃｏ、及びＡｌを含有していた。基材粒子（Ａ）全体を１００質量％とすると、Ｆｅの割合は７０．５質量％、Ｎｄは１．３３質量％、Ｄｙは０．４６質量％、Ｃｏは０．５１質量％、Ａｌは０．１９質量％であった。従って、基材粒子（Ａ）全体に対する不純物の質量比は２．４９質量％であった。基材粒子（Ａ）の全構成原子に対するＦｅの原子比は４２．６原子％であった。また、基材粒子（Ａ）のＢＥＴ比表面積は８．８ｍ２／ｇ、Ｄ５０粒径は４．１μｍであった。Example 1
Preparation of Substrate Particles Residual iron material generated in the process of recycling rare earth magnets was used as substrate particles (A). The substrate particles (A) mainly had an octahedral shape and contained Fe 3 O 4 as a main component. When X-ray diffraction measurement was performed, no peaks attributed to phases other than Fe 3 O 4 were confirmed. Further, as a result of ICP emission spectroscopic analysis, the substrate particles (A) contained Nd, Dy, Co, and Al in addition to Fe 3 O 4 . When the entire substrate particles (A) are 100% by mass, the proportion of Fe is 70.5% by mass, Nd is 1.33% by mass, Dy is 0.46% by mass, Co is 0.51% by mass, and Al is It was 0.19% by mass. Therefore, the mass ratio of impurities to the entire substrate particles (A) was 2.49 mass %. The atomic ratio of Fe to all constituent atoms of the substrate particles (A) was 42.6 atomic %. The BET specific surface area of the substrate particles (A) was 8.8 m 2 /g, and the D50 particle size was 4.1 μm.
負極材料の調製
５０ｍＬの純水に１０ｇの基材粒子（Ａ）を加えて撹拌し、これに５％ＮａＯＨ溶液を滴下してｐＨを９．０に調整し、スラリーを得た。一方、１０ｍＬの純水に０．０３１４ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾物質前駆体溶液を調製した。表面修飾物質前駆体溶液のうち１ｍＬを分取してスラリーに滴下し、更に５％ＮａＯＨ溶液を滴下しｐＨを９．０に調整した。ｐＨの変動が無いことを確認した後、得られたスラリーをヌッチェろ過し、純水で洗浄した。洗浄は洗浄液の導電率が３００μＳ／ｃｍ以下になるまで繰り返した。得られたケーキを２５０℃で２時間焼成して負極材料を得た。Preparation of Negative Electrode Material 10 g of substrate particles (A) were added to 50 mL of pure water and stirred, and a 5% NaOH solution was added dropwise to adjust the pH to 9.0 to obtain a slurry. On the other hand, 0.0314 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 10 mL of pure water to prepare a surface modifier precursor solution. 1 mL of the surface modifier precursor solution was taken and added dropwise to the slurry, and a 5% NaOH solution was added dropwise to adjust the pH to 9.0. After confirming that there was no change in pH, the obtained slurry was subjected to Nutsche filtration and washed with pure water. Washing was repeated until the conductivity of the washing liquid was 300 μS/cm or less. The obtained cake was baked at 250° C. for 2 hours to obtain a negative electrode material.
得られた負極材料では、１００質量％の基材粒子（Ａ）に対して０．０１質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。また、日本電子株式会社製フィールドエミッション電子プローブマイクロアナライザ（ＦＥＳＥＭ）ＪＸＡ－８５３０Ｆを用いて、この方法によって形成した表面修飾物質を観察し、５６個の粒子の平均粒径を求めたところ、約１００ｎｍであった。以下の実施例２～１７並びに比較例２、６、８、及び１０でも同様であった。 In the obtained negative electrode material, 0.01% by mass of the surface modifier adhered to 100% by mass of the base particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. In addition, using a field emission electron probe microanalyzer (FESEM) JXA-8530F manufactured by JEOL Ltd., the surface modifier formed by this method was observed, and the average particle size of 56 particles was obtained, which was about 100 nm. Met. The same was true for Examples 2-17 and Comparative Examples 2, 6, 8, and 10 below.
なお、実施例において、基材粒子の形状は、株式会社日立ハイテクノロジーズ製走査型電子顕微鏡（ＳＥＭ）Ｓ－３０００Ｎを用いて観察した。基材粒子及び表面修飾物質の組成は、パーキンエルマー社製ＩＣＰ発光分析装置Ｏｐｔｉｍａ８３００を用いたＩＣＰ分析及び株式会社リガク製Ｘ線回折装置ＵｌｔｉｍａＩＶを用いたＸＲＤ測定によって決定した。基材粒子のＢＥＴ比表面積は、ＭＯＵＮＴＥＣＨ社製比表面積測定装置Ｍａｃｓｏｒｂ ＨＭ－１２１０を用いて測定した。基材粒子のＤ５０粒径は、ＬＥＥＤＳ＆ＮＯＲＴＨＲＵＰ製レーザー回折式粒度分布計ＨＲＡ（マイクロトラック）を用いて測定した。 In the examples, the shape of the substrate particles was observed using a scanning electron microscope (SEM) S-3000N manufactured by Hitachi High-Technologies Corporation. The composition of the substrate particles and the surface modifier was determined by ICP analysis using an ICP emission spectrometer Optima 8300 manufactured by PerkinElmer and XRD measurement using an X-ray diffractometer Ultima IV manufactured by Rigaku Corporation. The BET specific surface area of the substrate particles was measured using a specific surface area measuring device Macsorb HM-1210 manufactured by MOUNTECH. The D50 particle size of the substrate particles was measured using a laser diffraction particle size distribution analyzer HRA (Microtrac) manufactured by LEEDS & NORTHRUP.
負極の作製
１．５ｇの上記負極材料及び電解質溶液（電解液）である０．３ｍＬのＫＯＨ水溶液（５Ｍ）を乳鉢中で１０分間混練し、負極を作製した。この負極材料の使用量を、鉄空気電池中の負極材料の充填量として表１に示す。Preparation of Negative Electrode 1.5 g of the above negative electrode material and 0.3 mL of KOH aqueous solution (5 M) as an electrolyte solution (electrolytic solution) were kneaded in a mortar for 10 minutes to prepare a negative electrode. The amount of this negative electrode material used is shown in Table 1 as the filling amount of the negative electrode material in the iron-air battery.
空気極の作製
ＭｎＯ２（東ソー株式会社製ＨＭＨ）と、アセチレンブラック（デンカ株式会社製デンカブラック）と、ポリフッ化ビニリデン溶液（株式会社クレハ製ＫＦポリマーＬ＃１１２０）とを、ＭｎＯ２：アセチレンブラック：ポリフッ化ビニリデンの質量比が２：０．０５：０．１となるよう秤量し、溶媒として１ｍＬのＮ－メチル－２－ピロリドンを加え、２時間混合して触媒スラリーを調製した。直径１４ｍｍに切り出した発泡ニッケル（住友電気工業株式会社製セルメット＃８）をこの触媒スラリーに浸漬した。このようにして触媒スラリーが塗布された発泡ニッケルを１６０℃に加熱したホットプレート上で３時間以上乾燥した後、６４ＭＰａで３０秒間プレスして、空気極（触媒層）を作製した。Preparation of Air Electrode MnO 2 (HMH manufactured by Tosoh Corporation), acetylene black (Denka Black manufactured by Denka Corporation), and a polyvinylidene fluoride solution (KF Polymer L#1120 manufactured by Kureha Corporation) were combined to form MnO 2 : acetylene black. : Polyvinylidene fluoride was weighed so that the mass ratio was 2:0.05:0.1, 1 mL of N-methyl-2-pyrrolidone was added as a solvent, and mixed for 2 hours to prepare a catalyst slurry. A nickel foam (Celmet #8 manufactured by Sumitomo Electric Industries, Ltd.) cut into a diameter of 14 mm was immersed in this catalyst slurry. The nickel foam coated with the catalyst slurry was dried on a hot plate heated to 160° C. for 3 hours or more, and then pressed at 64 MPa for 30 seconds to prepare an air electrode (catalyst layer).
鉄空気電池の作製
電池部材として宝泉株式会社製２０３２型コインセルパーツを用いた。負極ケース、ウェーブワッシャー、スペーサー、直径１６ｍｍに切り出した銅箔（福田金属箔粉工業株式会社製ＣＦ－Ｔ８Ｇ－ＳＴＤ－１８）、負極、直径１８ｍｍに切り出した濾紙（ＡＤＶＡＮＴＥＣ製５Ｃ）、空気極、及び空気孔付き空気極ケースをこの順に積層し、かしめ処理を行って鉄空気電池を作製した。ここで、銅箔は集電体として機能する。また、濾紙はセパレータとして機能し、且つ電解液を保持する役割も有する。Preparation of iron-air battery As a battery member, 2032 type coin cell parts manufactured by Hosen Co., Ltd. were used. Negative electrode case, wave washer, spacer, copper foil cut to 16 mm in diameter (CF-T8G-STD-18 manufactured by Fukuda Metal Foil & Powder Co., Ltd.), negative electrode, filter paper cut to 18 mm in diameter (5C manufactured by ADVANTEC), air electrode, and an air electrode case with an air hole were laminated in this order and crimped to fabricate an iron-air battery. Here, the copper foil functions as a current collector. Moreover, the filter paper functions as a separator and also has a role of retaining the electrolytic solution.
充放電試験
作製した鉄空気電池を用いて、温度２５℃、相対湿度１００％、充電電流３０ｍＡ、充電時間１時間、放電電流１０ｍＡ、放電下限電圧０Ｖ、及び充放電後休止時間３分の条件下、充放電を行った。この充放電を３０サイクル実施して、３０サイクル中で得られた最大の放電容量を当該鉄空気電池の「最大容量」とし、この最大容量が得られた放電時の平均電圧を「最大容量時電圧」とした。結果を表１に示す。Charge-discharge test Using the iron-air battery produced, the conditions are a temperature of 25 ° C., a relative humidity of 100%, a charging current of 30 mA, a charging time of 1 hour, a discharging current of 10 mA, a lower discharge voltage of 0 V, and a rest time of 3 minutes after charging and discharging. , was charged and discharged. This charge and discharge is carried out for 30 cycles, and the maximum discharge capacity obtained in 30 cycles is the "maximum capacity" of the iron-air battery, and the average voltage at the time of discharge when this maximum capacity is obtained is the "maximum capacity time voltage. Table 1 shows the results.
実施例２
５０ｍＬの純水に３０ｇの基材粒子（Ａ）を加えて撹拌し、これに０．００６４ｇの水酸化リチウム一水和物（和光純薬工業株式会社製）を溶解させてスラリーを得た。一方、１０ｍＬの純水に０．０９４２ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾物質前駆体溶液を調製した。この表面修飾物質前駆体溶液をスラリーに滴下し、ｐＨの変動が無いことを確認した後、得られたスラリーをヌッチェろ過し、純水で洗浄した。洗浄は洗浄液の導電率が３００μＳ／ｃｍ以下になるまで繰り返した。得られたケーキを２５０℃で２時間焼成して負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して０．１質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Example 2
30 g of substrate particles (A) were added to 50 mL of pure water and stirred, and 0.0064 g of lithium hydroxide monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved to obtain a slurry. On the other hand, 0.0942 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 10 mL of pure water to prepare a surface modifier precursor solution. This surface modifier precursor solution was added dropwise to the slurry, and after confirming that there was no change in pH, the resulting slurry was subjected to Nutsche filtration and washed with pure water. Washing was repeated until the conductivity of the washing liquid was 300 μS/cm or less. The obtained cake was baked at 250° C. for 2 hours to obtain a negative electrode material. In the obtained negative electrode material, 0.1% by mass of the surface modifier adhered to 100% by mass of the base particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
実施例３
５０ｍＬの純水に５０ｇの基材粒子（Ａ）を加えて撹拌し、これに０．１８１２ｇの水酸化リチウム一水和物（和光純薬工業株式会社製）を溶解させてスラリーを得た。一方、１０ｍＬの純水に０．５３９２ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾物質前駆体溶液を調製した。この表面修飾物質前駆体溶液をスラリーに滴下し、ｐＨの変動が無いことを確認した後、得られたスラリーをヌッチェろ過し、純水で洗浄した。洗浄は洗浄液の導電率が３００μＳ／ｃｍ以下になるまで繰り返した。得られたケーキを２５０℃で２時間焼成して負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して０．３質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Example 3
50 g of base particles (A) were added to 50 mL of pure water and stirred, and 0.1812 g of lithium hydroxide monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved to obtain a slurry. On the other hand, 0.5392 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 10 mL of pure water to prepare a surface modifier precursor solution. This surface modifier precursor solution was added dropwise to the slurry, and after confirming that there was no change in pH, the resulting slurry was subjected to Nutsche filtration and washed with pure water. Washing was repeated until the conductivity of the washing liquid was 300 μS/cm or less. The obtained cake was baked at 250° C. for 2 hours to obtain a negative electrode material. In the obtained negative electrode material, 0.3% by mass of the surface modifier adhered to 100% by mass of the substrate particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
実施例４
５０ｍＬの純水に５０ｇの基材粒子（Ａ）を加えて撹拌し、スラリーを得た。一方、３５ｍＬの純水に７．８４７４ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾物質前駆体溶液を調製した。チューブポンプを用いて滴下速度１ｍＬ／分で表面修飾物質前駆体溶液をスラリーに滴下した。このとき、５％ＮａＯＨ溶液を同時に滴下することで、スラリーのｐＨを９．０に保持した。ｐＨの変動が無いことを確認した後、得られたスラリーをヌッチェろ過し、純水で洗浄した。洗浄は洗浄液の導電率が３００μＳ／ｃｍ以下になるまで繰り返した。得られたケーキを２５０℃で２時間焼成して負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して５質量％の表面修飾物質が付着していた。実施例４の負極材料のＳＥＭ写真を図１に示す。粒径約１μｍ以下の比較的微細な基材粒子（Ａ）は概ね表面修飾物質粒子によって被覆されており、粒径が数μｍ程度の基材粒子（Ａ）では表面上に表面修飾物質粒子が均一に分散されていた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Example 4
50 g of base particles (A) were added to 50 mL of pure water and stirred to obtain a slurry. On the other hand, 7.8474 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 35 mL of pure water to prepare a surface modifier precursor solution. A tube pump was used to drop the surface modifier precursor solution into the slurry at a dropping rate of 1 mL/min. At this time, the pH of the slurry was maintained at 9.0 by dropping a 5% NaOH solution at the same time. After confirming that there was no change in pH, the obtained slurry was subjected to Nutsche filtration and washed with pure water. Washing was repeated until the conductivity of the washing liquid was 300 μS/cm or less. The obtained cake was baked at 250° C. for 2 hours to obtain a negative electrode material. In the obtained negative electrode material, 5% by mass of the surface modifier adhered to 100% by mass of the substrate particles (A). A SEM photograph of the negative electrode material of Example 4 is shown in FIG. Relatively fine substrate particles (A) having a particle size of about 1 μm or less are generally coated with surface modifier particles, and substrate particles (A) having a particle size of about several μm have surface modifier particles on their surfaces. It was evenly distributed. The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
実施例５
６０ｍＬの純水に１５．６９４８ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾物質前駆体溶液を調製したこと以外は実施例４と同様に負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して１０質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Example 5
A negative electrode in the same manner as in Example 4 except that 15.6948 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 60 mL of pure water to prepare a surface modifier precursor solution. got the material. In the obtained negative electrode material, 10% by mass of the surface modifier adhered to 100% by mass of the base particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
実施例６
５０ｍＬの純水に１０ｇの上記基材粒子（Ａ）を加えて撹拌してスラリーを調製し、２０ｍＬの純水に６．２７７９ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾液を調製したこと以外は実施例４と同様に負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して２０質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Example 6
Add 10 g of the base particles (A) to 50 mL of pure water and stir to prepare a slurry, add 6.2779 g of copper (II) sulfate pentahydrate (Wako Pure Chemical Industries, Ltd.) to 20 mL of pure water A negative electrode material was obtained in the same manner as in Example 4, except that the surface-modifying liquid was prepared by dissolving the material. In the obtained negative electrode material, 20% by mass of the surface modifier adhered to 100% by mass of the substrate particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
比較例１
表面修飾物質を形成せず（表面修飾処理を行わず）、上記基材粒子（Ａ）をそのまま負極材料として用いた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Comparative example 1
The substrate particles (A) were used as they were as a negative electrode material without forming a surface modifier (without performing a surface modification treatment). Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
比較例２
３０ｍＬの純水に９．４１６９ｇの硫酸銅（ＩＩ）五水和物（和光純薬工業株式会社製）を溶解させて表面修飾液を調製したこと以外は実施例６と同様に負極材料を得た。得られた負極材料では、１００質量％の基材粒子（Ａ）に対して３０質量％の表面修飾物質が付着していた。表面修飾物質はＣｕＯを主成分とし、５０原子％のＣｕを含有していた。この負極材料を用いて、実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Comparative example 2
A negative electrode material was obtained in the same manner as in Example 6, except that 9.4169 g of copper (II) sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 30 mL of pure water to prepare a surface modification liquid. rice field. In the obtained negative electrode material, 30% by mass of the surface modifier adhered to 100% by mass of the base particles (A). The surface modifier was mainly composed of CuO and contained 50 atom % of Cu. Using this negative electrode material, an iron-air battery was produced in the same manner as in Example 1, and a charge/discharge test was performed. Table 1 shows the results.
比較例３
１．０４ｇの上記基材粒子（Ａ）、０．１６ｇのカーボンブラック、及び０．３ｍＬのＫＯＨ水溶液（５Ｍ）を乳鉢中で１０分間混練して負極を作製したこと以外は実施例１と同様に鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。Comparative example 3
1.04 g of the base particles (A), 0.16 g of carbon black, and 0.3 mL of KOH aqueous solution (5 M) were kneaded in a mortar for 10 minutes to prepare a negative electrode. An iron-air battery was fabricated and a charge-discharge test was performed. Table 1 shows the results.
比較例４
１．５ｇの上記基材粒子（Ａ）と０．０７５ｇの銅粉末（株式会社高純度化学研究所製純銅４５μｍ ｐａｓｓ）とを混合し、得られた粉末のうち１．５ｇを０．３ｍＬのＫＯＨ水溶液（５Ｍ）と共に乳鉢中で１０分間混練して負極を作製したこと以外は実施例１と同様に、鉄空気電池を作製し、充放電試験を行った。結果を表１に示す。なお、得られた負極では、一次粒子径１μｍ程度の銅粒子が基材粒子（Ａ）と混合されていた。１００質量％の基材粒子（Ａ）に対する銅粒子の質量比は５質量％であった。Comparative example 4
1.5 g of the base particles (A) and 0.075 g of copper powder (pure copper 45 μm pass manufactured by Kojundo Chemical Laboratory Co., Ltd.) are mixed, and 1.5 g of the obtained powder is added to 0.3 mL. An iron-air battery was produced in the same manner as in Example 1, except that the negative electrode was produced by kneading with an aqueous KOH solution (5 M) in a mortar for 10 minutes, and a charge-discharge test was performed. Table 1 shows the results. In the obtained negative electrode, copper particles having a primary particle diameter of about 1 μm were mixed with the substrate particles (A). The mass ratio of the copper particles to 100 mass % of the base particles (A) was 5 mass %.
表１から明らかなように、実施例１～６においては、１００質量％の基材粒子に０．０１～２０質量％の表面修飾物質を付着させたことによって、鉄空気電池の最大容量が向上した。一方、表面修飾物質の質量比を３０質量％まで増加させた比較例２では、最大容量は向上したものの最大容量時電圧が大きく低下した。表面修飾物質の割合が増えるに従い基材粒子の割合が減少し、本来の鉄空気電池の反応に由来する放電成分が減少したと考えられる。また、本発明の表面修飾処理を行わず、導電助剤としてカーボンを用いた比較例３では、カーボンが嵩高いため電池ケース内に充填できる基材粒子の量が減少し、最大容量が低下した。本発明の表面修飾処理を行わず、導電助剤として銅粉末を用いた比較例４では、最大容量は向上したものの最大容量時電圧が低下した。本発明で基材粒子に付着させる表面修飾物質（ＣｕＯ等）と比較して、このような銅粉末は非常に粗大であり、また銅粉末は単に基材粒子と混合された状態で基材粒子表面に保持されていなかったため、導電性改善効果が不十分であった。 As is clear from Table 1, in Examples 1 to 6, the maximum capacity of the iron-air battery was improved by attaching 0.01 to 20% by mass of the surface modifier to 100% by mass of the base particles. did. On the other hand, in Comparative Example 2 in which the mass ratio of the surface modifier was increased to 30% by mass, although the maximum capacity was improved, the voltage at the maximum capacity was greatly reduced. It is thought that as the proportion of the surface modifier increased, the proportion of the substrate particles decreased, and the discharge component derived from the reaction of the original iron-air battery decreased. In Comparative Example 3, in which the surface modification treatment of the present invention was not performed and carbon was used as the conductive aid, the amount of base particles that could be filled in the battery case was reduced due to the bulkiness of the carbon, resulting in a decrease in the maximum capacity. . In Comparative Example 4, in which the surface modification treatment of the present invention was not performed and copper powder was used as the conductive aid, the maximum capacity was improved, but the voltage at the maximum capacity was lowered. Compared to the surface modifiers (CuO, etc.) attached to the substrate particles in the present invention, such copper powder is very coarse, and the copper powder is simply mixed with the substrate particles. Since it was not held on the surface, the conductivity improvement effect was insufficient.
実施例７～１０並びに比較例５及び６
基材粒子（Ａ）に替えて基材粒子（Ｂ）を使用し、負極材料の充填量を表２に示すとおり変更したこと以外は実施例２、３、５、及び６並びに比較例１及び２と同様に、実施例７～１０並びに比較例５及び６の鉄空気電池をそれぞれ作製し、充放電試験を行った。結果を表２に示す。Examples 7-10 and Comparative Examples 5 and 6
Examples 2, 3, 5, and 6 and Comparative Examples 1 and 6 except that the substrate particles (B) were used instead of the substrate particles (A), and the filling amount of the negative electrode material was changed as shown in Table 2. Iron-air batteries of Examples 7 to 10 and Comparative Examples 5 and 6 were produced in the same manner as in 2, and charge/discharge tests were performed. Table 2 shows the results.
なお、基材粒子（Ｂ）はＢＡＳＦ製カルボニル鉄ＳＱグレードであり、球状の形状を有し、Ｆｅを主成分として含有していた。蛍光Ｘ線分析（ＳＱＸ分析）を行ったところ、基材粒子（Ｂ）はＦｅに加えて微量のＳｉを含有しており、基材粒子（Ｂ）全体を１００質量％とすると、Ｆｅの質量比は９９．９質量％、Ｓｉは０．１質量％であった。基材粒子（Ｂ）の全構成原子に対するＦｅの原子比は９９．９８原子％であった。また、基材粒子（Ｂ）のＢＥＴ比表面積は０．４ｍ２／ｇ、Ｄ５０粒径は４．０μｍであった。The substrate particles (B) were carbonyl iron SQ grade manufactured by BASF, had a spherical shape, and contained Fe as a main component. Fluorescent X-ray analysis (SQX analysis) revealed that the substrate particles (B) contained a small amount of Si in addition to Fe. The ratio was 99.9 mass % and Si was 0.1 mass %. The atomic ratio of Fe to all constituent atoms of the substrate particles (B) was 99.98 atomic %. The BET specific surface area of the substrate particles (B) was 0.4 m 2 /g, and the D50 particle size was 4.0 μm.
表２から明らかなように、実施例７～１０においては、１００質量％の基材粒子に０．１～２０質量％の表面修飾物質を付着させたことによって、鉄空気電池の最大容量が向上した。基材粒子（Ｂ）を用いた場合、表面修飾物質の質量比が低いと最大容量改善効果はやや低かった。カルボニル鉄は酸化鉄よりも高い導電性を有するため、少量の表面修飾物質では効果が現れにくいものと考えられる。一方、表面修飾物質の質量比を３０質量％まで増加させた比較例６では、最大容量は向上したものの最大容量時電圧が大きく低下した。基材粒子（Ｂ）はＢＥＴ比表面積が小さいにもかかわらず、実施例１０では実施例１～６よりも大きな最大容量が得られた。基材粒子（Ｂ）は比重が大きいため、充填量を増やすことができ、そのため高容量となったと考えられる。 As is clear from Table 2, in Examples 7 to 10, the maximum capacity of the iron-air battery was improved by attaching 0.1 to 20% by mass of the surface modifier to 100% by mass of the base particles. did. When the substrate particles (B) were used, the effect of improving the maximum capacity was slightly low when the mass ratio of the surface modifier was low. Since carbonyl iron has a higher electrical conductivity than iron oxide, it is considered that a small amount of the surface modifier is unlikely to be effective. On the other hand, in Comparative Example 6 in which the mass ratio of the surface modifier was increased to 30% by mass, although the maximum capacity was improved, the voltage at the maximum capacity was greatly reduced. Although the base particles (B) had a small BET specific surface area, Example 10 provided a larger maximum capacity than Examples 1-6. Since the base particles (B) have a large specific gravity, it is thought that the filling amount can be increased, which is why the capacity is high.
実施例１１～１４並びに比較例７及び８
基材粒子（Ａ）に替えて基材粒子（Ｃ）を使用し、負極材料の充填量を表３に示すとおり変更したこと以外は実施例１、２、４、及び６並びに比較例１及び２と同様に、実施例１１～１４並びに比較例７及び８の鉄空気電池をそれぞれ作製し、充放電試験を行った。結果を表３に示す。Examples 11-14 and Comparative Examples 7 and 8
Examples 1, 2, 4, and 6 and Comparative Examples 1 and 6 except that the base particles (C) were used instead of the base particles (A), and the filling amount of the negative electrode material was changed as shown in Table 3. Iron-air batteries of Examples 11 to 14 and Comparative Examples 7 and 8 were produced in the same manner as in 2, and charge/discharge tests were performed. Table 3 shows the results.
なお、基材粒子（Ｃ）は和光純薬工業株式会社製Ｆｅ２Ｏ３粒子（酸化鉄（ＩＩＩ）、和光一級、商品コード０９６－０４８２５）であり、Ｆｅ２Ｏ３を主成分として含有していた。ＳＱＸ分析を行ったところ、基材粒子（Ｃ）はＦｅ２Ｏ３に加えてＡｌ、Ｓｉ、Ｐ、Ｓ、Ｃｌ、Ｃａ、Ｃｒ、Ｍｎ、Ｎｉ、Ｚｎ、及びＮｂを含有しており、基材粒子（Ｃ）全体を１００質量％とすると、Ｆｅの質量比は６９．５質量％、Ａｌは０．０３質量％、Ｓｉは０．０３質量％、Ｐは０．０１質量％、Ｓは０．０１質量％、Ｃｌは０．０６質量％、Ｃａは０．０１質量％、Ｃｒは０．０２質量％、Ｍｎは０．２５質量％、Ｎｉは０．０１質量％、Ｚｎは０．０２質量％であった。基材粒子（Ｃ）の全構成原子に対するＦｅの原子比は３９．９６原子％であった。また、基材粒子（Ｃ）のＢＥＴ比表面積は６．１ｍ２／ｇ、Ｄ５０粒径は１．９μｍであった。The substrate particles (C) are Fe 2 O 3 particles (iron oxide (III), Wako first grade, product code 096-04825) manufactured by Wako Pure Chemical Industries, Ltd., and contain Fe 2 O 3 as a main component. was SQX analysis revealed that the base particles (C) contained Al, Si, P, S, Cl, Ca, Cr, Mn, Ni, Zn, and Nb in addition to Fe 2 O 3 . When the entire material particles (C) is 100% by mass, the mass ratio of Fe is 69.5% by mass, Al is 0.03% by mass, Si is 0.03% by mass, P is 0.01% by mass, and S is 0.01% by mass, Cl 0.06% by mass, Ca 0.01% by mass, Cr 0.02% by mass, Mn 0.25% by mass, Ni 0.01% by mass, and Zn 0.01% by mass. 02% by mass. The atomic ratio of Fe to all constituent atoms of the substrate particles (C) was 39.96 atomic %. Further, the BET specific surface area of the substrate particles (C) was 6.1 m 2 /g, and the D50 particle size was 1.9 μm.
表３から明らかなように、実施例１１～１４においては、１００質量％の基材粒子に０．０１～２０質量％の表面修飾物質を付着させたことによって、鉄空気電池の最大容量が向上した。一方、表面修飾物質の質量比を３０質量％まで増加させた比較例８では、最大容量は向上したものの最大容量時電圧が大きく低下した。 As is clear from Table 3, in Examples 11 to 14, the maximum capacity of the iron-air battery was improved by attaching 0.01 to 20% by mass of the surface modifier to 100% by mass of the base particles. did. On the other hand, in Comparative Example 8 in which the mass ratio of the surface modifier was increased to 30% by mass, although the maximum capacity was improved, the voltage at the maximum capacity was greatly reduced.
実施例１５～１７並びに比較例９及び１０
基材粒子（Ａ）に替えて基材粒子（Ｄ）を使用し、負極材料の充填量を表４に示すとおり変更したこと以外は実施例２、５、及び６並びに比較例１及び２と同様に、実施例１５～１７並びに比較例９及び１０の鉄空気電池をそれぞれ作製し、充放電試験を行った。結果を表４に示す。Examples 15-17 and Comparative Examples 9 and 10
Examples 2, 5, and 6 and Comparative Examples 1 and 2, except that the base particles (D) were used instead of the base particles (A), and the filling amount of the negative electrode material was changed as shown in Table 4. Similarly, iron-air batteries of Examples 15 to 17 and Comparative Examples 9 and 10 were produced and subjected to charge/discharge tests. Table 4 shows the results.
なお、基材粒子（Ｄ）は次のとおり均一沈殿法によって調製した。まず、硫酸鉄（ＩＩ）七水和物及び尿素（共に和光純薬工業株式会社製）を純水に溶解し、１２０℃に加熱したホットプレートを用いて尿素の分解を促してｐＨを制御した。この溶液を溶液温度９０℃で１０分間保持して沈殿を生成させた後、２４％ＮａＯＨを添加してｐＨを１０まで上昇させ、粒径を固定した。得られた沈殿をろ過により分離し、洗浄して基材粒子（Ｄ）を得た。基材粒子（Ｄ）はＦｅ３Ｏ４を主成分として含有していた。ＳＱＸ分析を行ったところ、基材粒子（Ｄ）はＦｅ３Ｏ４に加えてＮａ、Ｓｉ、Ｐ、Ｓ、Ｍｎ、Ｎｉ、及びＣｕを含有しており、基材粒子（Ｄ）全体を１００質量％とすると、Ｆｅの質量比は７２．１質量％、Ｎａは０．０５質量％、Ｓｉは０．０２質量％、Ｓは０．１０質量％、Ｍｎは０．０２質量％、Ｎｉは０．０２質量％、Ｃｕは０．０１質量％であった。基材粒子（Ｄ）の全構成原子に対するＦｅの原子比は４２．５９原子％であった。また、基材粒子（Ｄ）のＢＥＴ比表面積は５９．１ｍ２／ｇ、Ｄ５０粒径は１．２μｍであった。The substrate particles (D) were prepared by a uniform precipitation method as follows. First, iron (II) sulfate heptahydrate and urea (both manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved in pure water, and a hot plate heated to 120° C. was used to accelerate the decomposition of urea and control the pH. . The solution was held at a solution temperature of 90° C. for 10 minutes to form a precipitate, after which 24% NaOH was added to raise the pH to 10 to fix the particle size. The resulting precipitate was separated by filtration and washed to obtain substrate particles (D). The substrate particles (D) contained Fe 3 O 4 as a main component. SQX analysis revealed that the base particles (D) contained Na, Si, P, S, Mn, Ni, and Cu in addition to Fe 3 O 4 . Assuming mass %, the mass ratio of Fe is 72.1 mass %, Na is 0.05 mass %, Si is 0.02 mass %, S is 0.10 mass %, Mn is 0.02 mass %, Ni is 0.02% by mass and Cu was 0.01% by mass. The atomic ratio of Fe to all constituent atoms of the substrate particles (D) was 42.59 atomic %. Further, the BET specific surface area of the substrate particles (D) was 59.1 m 2 /g, and the D50 particle size was 1.2 μm.
表４から明らかなように、実施例１５～１８においては、１００質量％の基材粒子に０．１～２０質量％の表面修飾物質を付着させたことによって、鉄空気電池の最大容量が向上した。基材粒子（Ｄ）を用いた場合、表面修飾物質の質量比が低いと最大容量改善効果はやや低かった。基材粒子（Ｄ）は比較的大きな表面積を有するため、少量の表面修飾物質では効果が現れにくいものと考えられる。一方、表面修飾物質の質量比を３０質量％まで増加させた比較例１０では、最大容量は向上したものの最大容量時電圧が大きく低下した。なお、実施例１７では最大容量が比較例９よりも低くなっているが、これは充填量が異なることに起因する。負極材料の単位質量あたりの容量は、実施例１７では１６．３ｍＡｈ／ｇ、比較例９では１３．７ｍＡｈ／ｇであり、実施例１７でも表面修飾物質による容量改善効果が示されている。 As is clear from Table 4, in Examples 15 to 18, the maximum capacity of the iron-air battery was improved by attaching 0.1 to 20% by mass of the surface modifier to 100% by mass of the base particles. did. When the substrate particles (D) were used, the effect of improving the maximum capacity was slightly low when the mass ratio of the surface modifier was low. Since the substrate particles (D) have a relatively large surface area, it is considered that a small amount of the surface modifying substance is unlikely to be effective. On the other hand, in Comparative Example 10 in which the mass ratio of the surface modifier was increased to 30% by mass, although the maximum capacity was improved, the voltage at the maximum capacity was greatly reduced. Note that the maximum capacity of Example 17 is lower than that of Comparative Example 9, but this is due to the difference in filling amount. The capacity per unit mass of the negative electrode material was 16.3 mAh/g in Example 17 and 13.7 mAh/g in Comparative Example 9, and Example 17 also shows the capacity improvement effect of the surface modifier.
Claims (5)
前記基材粒子が３０原子％以上１００原子％以下のＦｅを含み、
前記表面修飾物質が２０原子％以上１００原子％以下のＣｕを含み、
１００質量％の前記基材粒子に対する前記表面修飾物質の質量比が０．００５質量％以上２５質量％以下である、
鉄空気電池用負極材料。 Consists of a base particle and a surface modifier attached to the surface of the base particle,
The substrate particles contain 30 atomic % or more and 100 atomic % or less of Fe,
The surface modifier contains 20 atomic % or more and 100 atomic % or less of Cu,
The mass ratio of the surface modifier to 100% by mass of the substrate particles is 0.005 % by mass or more and 25 % by mass or less ,
Anode materials for iron-air batteries.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017079268 | 2017-04-12 | ||
| JP2017079268 | 2017-04-12 | ||
| PCT/JP2018/015303 WO2018190390A1 (en) | 2017-04-12 | 2018-04-11 | Negative electrode material, negative electrode and iron-air battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPWO2018190390A1 JPWO2018190390A1 (en) | 2020-02-27 |
| JP7141809B2 true JP7141809B2 (en) | 2022-09-26 |
Family
ID=63792666
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2019512562A Active JP7141809B2 (en) | 2017-04-12 | 2018-04-11 | Anode Materials, Anodes, and Iron-Air Batteries |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP7141809B2 (en) |
| WO (1) | WO2018190390A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113390800B (en) * | 2020-03-13 | 2022-05-20 | 宁德新能源科技有限公司 | Method for detecting content of copper simple substance in lithium battery positive electrode material |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012094509A (en) | 2010-10-01 | 2012-05-17 | Kyushu Univ | Composite electrode material and method for producing the same, negative electrode for metal air battery, and metal air battery |
| JP2013165052A (en) | 2012-01-11 | 2013-08-22 | Kobe Steel Ltd | Material for air cell and all-solid air cell using the same |
| JP2015216109A (en) | 2014-04-21 | 2015-12-03 | 京セラ株式会社 | Negative electrode for air battery, and solid electrolyte air battery using the same |
-
2018
- 2018-04-11 JP JP2019512562A patent/JP7141809B2/en active Active
- 2018-04-11 WO PCT/JP2018/015303 patent/WO2018190390A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012094509A (en) | 2010-10-01 | 2012-05-17 | Kyushu Univ | Composite electrode material and method for producing the same, negative electrode for metal air battery, and metal air battery |
| JP2013165052A (en) | 2012-01-11 | 2013-08-22 | Kobe Steel Ltd | Material for air cell and all-solid air cell using the same |
| JP2015216109A (en) | 2014-04-21 | 2015-12-03 | 京セラ株式会社 | Negative electrode for air battery, and solid electrolyte air battery using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2018190390A1 (en) | 2018-10-18 |
| JPWO2018190390A1 (en) | 2020-02-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Leng et al. | Pd nanoparticles decorating flower-like Co 3 O 4 nanowire clusters to form an efficient, carbon/binder-free cathode for Li–O 2 batteries | |
| JP5314264B2 (en) | Method for producing positive electrode active material for lithium secondary battery, positive electrode active material and lithium secondary battery | |
| Kim et al. | Formation of carbon-coated ZnFe 2 O 4 nanowires and their highly reversible lithium storage properties | |
| JP2023551742A (en) | Lithium manganese iron phosphate precursor, lithium manganese iron phosphate positive electrode material and manufacturing method thereof, electrode material, electrode, and lithium ion battery | |
| WO2019189014A1 (en) | Method for producing catalyst for air secondary batteries, method for producing air secondary battery, catalyst for air secondary batteries, and air secondary battery | |
| WO2015115592A1 (en) | Catalyst for air electrode for metal/air secondary battery, and air electrode | |
| WO2020044795A1 (en) | Positive electrode active material particles for secondary batteries, and method for producing positive electrode active material particles for secondary batteries | |
| JP7290626B2 (en) | Positive electrode compound and method for producing positive electrode active material | |
| JP2017179473A (en) | Metallic porous body and manufacturing method therefor, negative electrode material and lithium ion secondary battery | |
| JP2009200013A (en) | Lithium secondary battery, its positive electrode active substance, and its manufacturing method | |
| JP5850548B2 (en) | Method for producing cobalt cerium compound | |
| JP7141809B2 (en) | Anode Materials, Anodes, and Iron-Air Batteries | |
| WO2012096291A1 (en) | Alkaline storage battery | |
| JP6422017B2 (en) | Hydrogen storage alloy, electrode and nickel metal hydride storage battery | |
| CN108352520B (en) | Zinc negative electrode material for secondary battery | |
| KR20210002567A (en) | Positive electrode active material, positive electrode, alkaline storage battery, and method of manufacturing positive electrode active material | |
| TW201607125A (en) | Negative electrode material for lithium-ion secondary batteries and method for manufacturing the same, negative electrode for lithium-ion secondary batteries, and lithium-ion secondary battery | |
| JP6153156B2 (en) | Hydrogen storage alloy and nickel metal hydride secondary battery using this hydrogen storage alloy | |
| JP5743185B2 (en) | Positive electrode active material for alkaline storage battery and alkaline storage battery | |
| JP6213316B2 (en) | Nickel hydroxide nickel hydroxide and alkaline storage battery for alkaline storage battery | |
| JP6394955B2 (en) | Hydrogen storage alloy, electrode and nickel metal hydride storage battery | |
| JP7176942B2 (en) | alkaline battery | |
| JP2015018621A (en) | Sodium battery cathode active material and method of producing the same | |
| JP5769028B2 (en) | Nickel metal hydride storage battery | |
| JP7290625B2 (en) | Positive electrode compound and method for producing positive electrode active material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20210401 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20220517 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20220629 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20220823 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20220910 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7141809 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |