WO2014014311A1 - Method for preparing positive electrode active material for magnesium secondary battery and positive electrode active material for magnesium secondary battery prepared by the method - Google Patents

Method for preparing positive electrode active material for magnesium secondary battery and positive electrode active material for magnesium secondary battery prepared by the method Download PDF

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WO2014014311A1
WO2014014311A1 PCT/KR2013/006489 KR2013006489W WO2014014311A1 WO 2014014311 A1 WO2014014311 A1 WO 2014014311A1 KR 2013006489 W KR2013006489 W KR 2013006489W WO 2014014311 A1 WO2014014311 A1 WO 2014014311A1
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active material
secondary battery
magnesium secondary
magnesium
cathode active
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PCT/KR2013/006489
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French (fr)
Korean (ko)
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조우석
김점수
김재헌
우상길
김영준
문보라
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전자부품연구원
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Priority claimed from KR1020130085198A external-priority patent/KR101542838B1/en
Publication of WO2014014311A1 publication Critical patent/WO2014014311A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/581—Chalcogenides or intercalation compounds thereof
    • H01M4/5815—Sulfides
    • 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

Definitions

  • the present invention relates to a method for manufacturing a cathode active material for magnesium secondary battery and a cathode active material for magnesium secondary battery produced by the same, and more particularly, to a cathode active material for magnesium secondary battery that can increase reaction efficiency and lower side reaction ratio by controlling particle size. It relates to a manufacturing method and a cathode active material for magnesium secondary battery produced thereby.
  • lithium secondary batteries have high manufacturing costs per cell due to the cost of transition metals used for manufacturing despite the excellent performance, and there is a risk of ignition or explosion due to the high reactivity of lithium, and there is concern about depletion of lithium resources.
  • Recently, research on magnesium batteries has been actively conducted as an alternative.
  • Magnesium batteries are generally secondary batteries that use magnesium metal, etc. as a negative electrode, and are capable of charging and discharging by inserting and detaching magnesium ions into a cathode material. Magnesium is resource-rich, much cheaper than lithium, and The energy capacity per volume is theoretically more than twice that of a lithium ion battery, and is stable in the air, thus attracting attention as a next-generation secondary battery.
  • a magnesium battery using a Chevrel phase such as Mo 6 S 8 or molybdenum sulfide as a cathode material and Mg (AlCl 2 BuEt) 2 / THF as an electrolyte is known.
  • Molybdenum chalcogen compound, so-called Chevrel phase Mo 6 S 8 is known to be the most promising positive electrode active material of Mg secondary battery because of the fast cation transfer properties.
  • Mo 6 S 8 is applied as a cathode material of a magnesium secondary battery, magnesium ions inserted in the initial discharging stage (Mo 6 S 8 ⁇ Mg 2 Mo 6 S 8 ) partially trapped within the magnesium position.
  • the Chevrel phase is thermodynamically metastable, and thus is manufactured by an indirect method of removing metallic copper from a stable phase such as Cu 2 Mo 6 S 8 . It may be convenient to prepare the positive electrode active material Mg 2 Mo 6 S 8 directly by the high temperature solid-state reaction, but the Mg 2 Mo 6 S 8 prepared by the direct method has electrochemical activity due to the magnesium oxide (MgO) oxide film formed on the surface. Reported bad. Therefore, a method of preparing a stable phase such as Cu 2 Mo 6 S 8 to remove metal copper and refilling magnesium in place is used to prepare Mg 2 Mo 6 S 8 cathode active material.
  • a stable phase such as Cu 2 Mo 6 S 8 to remove metal copper and refilling magnesium in place is used to prepare Mg 2 Mo 6 S 8 cathode active material.
  • the present invention relates to a new method for producing a cathode active material for chevron structure magnesium secondary battery, and to provide a method for producing a cathode active material for chevron structure magnesium particles of which the particle size is controlled to a nano size.
  • Another object of the present invention is to provide a cathode active material for magnesium secondary batteries produced by the production method of the present invention.
  • the present invention to solve the above problems
  • It provides a method for producing a cathode active material for magnesium secondary battery comprising a.
  • the Mo compound is for example molybdenum oxide
  • the elemental X compound may be, for example, carbon disulfide, hydrogen sulfide, hydrogen selenide, hydrogen selenide.
  • the element A occupies a wyckoff position 18f, and is selected from the group consisting of Cu, Fe, Co, Ni, Cd, Zn, Mn, and Ag.
  • Silver may be, for example, copper oxide, iron oxide, cobalt oxide, manganese acetate and the like.
  • the Wycope position is Ralph W.G.
  • the 'position' in the Wykov position of the decision group refers to the position of the crystal in the stereographic projection.
  • the decision group also describes the Wykov position as the Wyck letter, whereby the element A occupies the 18 f position.
  • the step i) is characterized in that the stirring so that the particle size in the Mechano fusion apparatus 10nm to 100nm.
  • the particle size of the positive electrode active material is adjusted to a range of 10 nm to 100 nm by applying energy and stirring, whereby the positive electrode active material has a high specific surface area, thereby facilitating the transfer of magnesium ions between particles.
  • the Mechano fusion apparatus is characterized in that the high energy ball mill (high energy ball mill), planetary mill (planetary mill), stirred ball mill (stirred ball mill) or vibrating mill (vibrating mill).
  • high energy ball mill high energy ball mill
  • planetary mill planetary mill
  • stirred ball mill stirred ball mill
  • vibrating mill vibrating mill
  • the step ii) is characterized in that the mixture of step i) is heat-treated in an inert atmosphere for 20 to 25 hours at 1000 °C to 1200 °C.
  • the heat treatment in an inert atmosphere is to prevent oxidation of the metal, the inert atmosphere may be, for example, argon, nitrogen atmosphere, preferably an argon atmosphere.
  • step iii) A is released in the presence of an oxidizing agent, and magnesium ions are inserted.
  • the oxidizing agent is a substance that oxidizes a counterpart while reducing itself in a redox reaction, and serves to desorb A, and may use nitric acid, perchloric acid, hydrochloric acid, and the like, preferably hydrochloric acid.
  • A in step iii), as another method, A may be detached by ion exchange and magnesium ions may be inserted. It is possible to replace A with magnesium in part or in whole.
  • the ion exchange method is a method in which ion exchange occurs between magnesium contained in the magnesium-containing liquid and A constituting the cathode active material-forming material by adding the positive electrode active material forming material to the magnesium-containing liquid.
  • the magnesium containing liquid include MgCl 2 and the like.
  • the magnesium-containing liquid used in the present invention may be an electrolyte solution used in the magnesium secondary battery. As the solvent, it is possible to use Mg (NO 3 ) 2 or the like.
  • Heat may be used as an example of a method of advancing ion exchange by an ion exchange method.
  • the method using heat is a method in which an ion exchange reaction proceeds by adding a positive electrode active material forming material to a magnesium-containing liquid and heating it.
  • the use of heat can result in good ion exchange reactions being carried out in a short time.
  • Heating temperature is 300-400 degreeC normally, and 330-350 degreeC is preferable.
  • the heating time is usually 1 to 10 hours, preferably 2 to 5 hours.
  • the present invention also provides a cathode active material for a magnesium secondary battery prepared by the production method of the present invention and represented by the following general formula (2).
  • the cathode active material for magnesium secondary battery has a Chevrel structure, characterized in that the magnesium ion is inserted / detached by an electrochemical method or a chemical method.
  • the cathode active material produced by the production method of the present invention is characterized by consisting of particles of 10 nm or more and 500 nm or less in diameter.
  • the production method of the present invention has a high specific surface area by controlling the size of the particles in such a range, thereby facilitating the transfer of magnesium ions between particles.
  • the activation energy required to insert magnesium ions into the positive electrode active material is 0.4-0.6 eV, characterized in that the voltage of the electrochemical cell generated at this time appears in the 1.0-1.2 V region.
  • the activation energy is, with a minimum of energy required to insert the magnesium Mo 6 S 8 0.6eV, Mo 6 Se 8 In may have a 0.4 eV.
  • the positive electrode active material is a single phase when the y value is 0 or 2, it is characterized in that the two phase when the y value is 0 to 2. That is, in the present invention, the positive electrode active material is characterized in that the phase change occurs in a single phase-> two phase-> single phase as the y value is changed from 0 to 2, that is, magnesium ions are inserted.
  • the single phase and when the y value is 0 to 2 the two phases belong to the R-3 space group of the rombohedral and have different lattice constants.
  • Rombohedral can be regarded as a cubic system of the form
  • the present invention also provides a magnesium secondary battery prepared by the present invention and including a magnesium cathode active material having a chevron structure whose particle size is controlled to a nano size.
  • the voltage of the magnesium secondary battery including the magnesium cathode active material of the Chevrel structure whose particle size is controlled by nano size according to the present invention is 1.0 to 1.2V.
  • Magnesium secondary battery according to the present invention includes a positive electrode, a negative electrode, a binder.
  • the positive electrode may further include a positive electrode active material, and a binder or a conductive material according to the present invention.
  • the conductive material may be used for anything used in the magnesium secondary battery.
  • Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, and carbon fiber; Metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive materials such as polyphenylene derivatives; Or combinations thereof.
  • the binder adheres well to the positive electrode active material particles, and also serves to adhere the positive electrode active material to the current collector.
  • Representative examples of the binder include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinylchloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpi Ralidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resins, nylon or combinations thereof may be used.
  • the anode may be formed in a shape of the anode forming material itself, or the anode forming material is coated on a current collector such as copper foil, nickel foil, or stainless steel foil. It can manufacture by the method of doing.
  • the negative electrode may be at least one selected from the group consisting of a magnesium single material and an alloy containing magnesium.
  • the cathode may be a magnesium disk.
  • the magnesium secondary battery of the present invention further includes an electrolyte.
  • the electrolyte may be a magnesium ion-containing nonaqueous electrolyte.
  • the electrolyte may be a solution in which a magnesium salt such as Mg (AlCl 2 EtBu) 2 is dissolved in an organic solvent such as tetrahydrofuran (THF).
  • a magnesium salt such as Mg (AlCl 2 EtBu) 2
  • Et is an ethyl group
  • Bu is a butyl group.
  • the magnesium secondary battery may further include a separator that physically and electrically separates the positive electrode and the negative electrode from each other.
  • the separator may be one commonly used in magnesium batteries.
  • Such a separator may be a glass filter, polyester, teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) or a combination thereof.
  • PTFE polytetrafluoroethylene
  • such a separator may be in the form of a woven fabric or a nonwoven fabric.
  • the method for manufacturing a cathode active material for magnesium secondary battery according to the present invention not only prevents impurities from being formed even at a low temperature by adjusting the particle size when mixing the raw material compounds, and has a chevron structure cathode active material manufactured by the manufacturing method of the present invention. Insertion and desorption of silver magnesium ions is facilitated, thereby improving the diffusion of magnesium ions in the magnesium secondary battery.
  • FIG. 1 is a schematic diagram showing a method for producing a cathode active material for magnesium secondary battery according to the present invention.
  • Figure 2 shows the X-ray diffraction pattern of the positive electrode active material for magnesium secondary battery prepared according to an embodiment of the present invention.
  • Figure 3 shows a SEM photograph of the positive electrode active material for magnesium secondary battery prepared by one embodiment and comparative example of the present invention.
  • Figure 4 shows the charge and discharge curve of the magnesium secondary battery comprising a cathode active material for magnesium secondary battery prepared according to an embodiment and a comparative example of the present invention.
  • FIG. 5 is a graph illustrating output characteristics of a magnesium secondary battery including a cathode active material for magnesium secondary battery manufactured according to an embodiment and a comparative example of the present invention.
  • Cu, Mo element compound and S as X element were mixed as starting material A element compound, and it stirred at 480 rpm for 6 hours for High energy milling machine. Subsequently, the compound represented by Cu 2.5 Mo 6 S 8 was synthesized by placing it in a Swagelok reactor and heat-treating at 1100 ° C. for 24 hours in an argon (Ar) gas atmosphere. Thereafter, copper was desorbed from the Cu 2.5 Mo 6 S 8 using HCl as an oxidant to form Mo 6 S 8 particles.
  • Example 1 SEM pictures of the cathode active materials prepared in Example 1 and Comparative Example 1 were measured and the results are shown in FIG. 1.
  • the cathode active material of Comparative Example 1 had an average size of primary particles of 2 ⁇ m, whereas in Example 1, the size of primary particles was controlled to a nano size, that is, 500 nm or less.
  • a positive electrode including the active material of Mo 6 S 8 prepared in Example 1 and Comparative Example 1 was prepared.
  • Example 1 80 parts by weight of the positive electrode active material prepared in Example 1 and Comparative Example 1, 10 parts by weight of denca black as a conductive material and 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder were mixed.
  • the mixture was dispersed in N-methyl-pyrrolidone (NMP) to prepare a slurry for positive electrode formation. Thereafter, the slurry was coated to a thickness of 70 ⁇ m on a stainless steel foil having a thickness of 10 ⁇ m, dried, and pressed at a compression ratio of 20-25% using a roll press machine at 120 ° C. to prepare a positive electrode.
  • NMP N-methyl-pyrrolidone
  • a coin cell was manufactured using a magnesium secondary battery positive electrode prepared in Example 2 and a magnesium disc and a separator as a negative electrode.
  • the coin cell prepared in Example 3 was initially charged and discharged three times, and the results are shown in FIG. 4.
  • Example 1 For the coin cell including the magnesium secondary battery positive electrode of Example 1 and Comparative Example 1 prepared in Example 3 by measuring the output characteristics to 0.05, 0.1, 0.2, 0.5, 1, 2, 5C The results are shown in FIG. 5.
  • the discharge capacity retention rate of Example 1 was 95.6% at 5C compared to the initial 0.05 C.
  • Comparative Example 1 55.3% was shown. From this, the primary particle size was controlled by the present invention, thereby significantly improving the output characteristics.
  • the method for producing a cathode active material for magnesium secondary battery according to the present invention not only prevents impurities from being formed even at low temperatures by controlling the particle size when mixing the raw material compounds, and is prepared by the method of the present invention.
  • the cathode active material of the Brel structure facilitates the insertion and removal of magnesium ions, thereby improving the diffusion of magnesium ions in the magnesium secondary battery.

Abstract

The present invention relates to a method for preparing a positive electrode active material for a magnesium secondary battery and to a positive electrode active material for a magnesium secondary battery prepared by the method. More particularly, the present invention relates to a method for preparing a positive electrode active material for a magnesium secondary battery in which the particle size of the positive electrode active material is controlled to achieve improved reaction efficiency and reduce side reactions, and to a positive electrode active material for a magnesium secondary battery prepared by the method.

Description

마그네슘 이차전지용 양극활물질의 제조 방법 및 이에 의하여 제조된 마그네슘 이차전지용 양극활물질Method for manufacturing cathode active material for magnesium secondary battery and cathode active material for magnesium secondary battery produced thereby
본 발명은 마그네슘 이차전지용 양극활물질의 제조 방법 및 이에 의하여 제조된 마그네슘 이차전지용 양극활물질에 관한 것으로서, 더욱 상세하게는 입자 크기를 제어함으로써 반응 효율을 높이고 부반응 비율을 낮출 수 있는 마그네슘 이차전지용 양극활물질의 제조 방법 및 이에 의하여 제조된 마그네슘 이차전지용 양극활물질에 관한 것이다.The present invention relates to a method for manufacturing a cathode active material for magnesium secondary battery and a cathode active material for magnesium secondary battery produced by the same, and more particularly, to a cathode active material for magnesium secondary battery that can increase reaction efficiency and lower side reaction ratio by controlling particle size. It relates to a manufacturing method and a cathode active material for magnesium secondary battery produced thereby.
모바일 기기에 대한 기술 개발과 수요가 증가함에 따라 에너지원으로서의 이차전지의 수요가 급격히 증가하고 있고, 그러한 이차전지 중 높은 에너지 밀도와 방전 전압의 리튬 이차 전지에 대해 많은 연구가 행해졌고 또한 상용화되어 널리 사용되고 있다. As the development and demand for mobile devices increases, the demand for secondary batteries as energy sources is increasing rapidly. Among them, many researches have been conducted and commercialized and widely used for lithium secondary batteries with high energy density and discharge voltage. It is used.
그러나, 리튬 이차 전지는 뛰어난 성능에도 불구하고 제조를 위해 사용되는 전이금속의 비용에 의해 셀당 제조 비용이 높으며, 리튬의 반응성이 높아 발화나 폭발의 위험이 있고, 리튬 자원의 고갈이 우려되는 바, 최근에는 그 대안으로 마그네슘 전지에 대한 연구가 활발히 진행되고 있다.However, lithium secondary batteries have high manufacturing costs per cell due to the cost of transition metals used for manufacturing despite the excellent performance, and there is a risk of ignition or explosion due to the high reactivity of lithium, and there is concern about depletion of lithium resources. Recently, research on magnesium batteries has been actively conducted as an alternative.
마그네슘 전지는 일반적으로 마그네슘 금속 등을 음극으로 사용하여 마그네슘 이온이 양극재에 삽입-탈리되어 충방전이 가능하게 되는 2차 전지로, 마그네슘은 자원적으로 풍부하고, 리튬에 비하여 훨씬 저가이면서, 단위 체적당 에너지 용량이 리튬 이온 전지에 비하여 이론적으로 2배 이상이고, 대기 중에서 안정하여 차세대 이차전지로 주목받고 있다. Magnesium batteries are generally secondary batteries that use magnesium metal, etc. as a negative electrode, and are capable of charging and discharging by inserting and detaching magnesium ions into a cathode material. Magnesium is resource-rich, much cheaper than lithium, and The energy capacity per volume is theoretically more than twice that of a lithium ion battery, and is stable in the air, thus attracting attention as a next-generation secondary battery.
현재까지 Mo6S8, 또는 황화몰리브덴과 같은 쉐브렐상을 양극재로, Mg(AlCl2BuEt)2/THF을 전해액으로 사용하는 마그네슘 전지가 알려져 있다. 몰리브덴칼코겐 화합물, 소위 Chevrel 상, Mo6S8 는 빠른 양이온 전달 특성 때문에 Mg 이차전지의 양극 활물질로 가장 유망한 것으로 알려져 있다. 그러나, 실제 Mo6S8를 마그네슘 이차전지의 양극재로 적용시킬 경우, 초기 방전단계에서 (Mo6S8→Mg2Mo6S8) 삽입된 마그네슘 이온이 마그네슘 위치 내에서 부분적으로 트래핑(Trapping) 되는 현상이 발생되며, 이는 마그네슘 이온의 2 전자가에 의한 호스트(Host) 구조내 마그네슘 이온 삽입시 발생하는 강한 상호반응(interaction)에 의해 마그네슘 이온이 호스트(Host) 구조 내에 부분적으로 갖혀서 충전시 나오지 못하는 것이 문제가 된다. 이러한 현상을 트래핑 효과(Trapping effect)라 하며 이는 용량의 감소로 나타나게 된다. 보고에 의하면 실온에서의 Mg2Mo6S8의 방전용량은 이론용량의 60%인 73 mAhg-1정도로 알려져 있다. 따라서, Mg2Mo6S8 는 호스트(Host) 구조 내 마그네슘 이온의 고체 내 확산 (Solid-state diffusion)에 기인한 마그네슘 이온의 확산이 문제가 되고 있다. To date, a magnesium battery using a Chevrel phase such as Mo 6 S 8 or molybdenum sulfide as a cathode material and Mg (AlCl 2 BuEt) 2 / THF as an electrolyte is known. Molybdenum chalcogen compound, so-called Chevrel phase, Mo 6 S 8 is known to be the most promising positive electrode active material of Mg secondary battery because of the fast cation transfer properties. However, when Mo 6 S 8 is applied as a cathode material of a magnesium secondary battery, magnesium ions inserted in the initial discharging stage (Mo 6 S 8 → Mg 2 Mo 6 S 8 ) partially trapped within the magnesium position. This phenomenon occurs when the magnesium ions are partially contained in the host structure by the strong interaction generated when the magnesium ions are inserted into the host structure by the two electrons of magnesium ions. Failure to come out is a problem. This phenomenon is called the trapping effect, which results in a decrease in capacity. It is reported that the discharge capacity of Mg 2 Mo 6 S 8 at room temperature is about 73 mAhg −1 , which is 60% of the theoretical capacity. Therefore, Mg 2 Mo 6 S 8 has a problem of diffusion of magnesium ions due to the solid-state diffusion of magnesium ions in the host structure.
한편 쉐브렐상은 열역학적으로 준안정상이기 때문에 Cu2Mo6S8와 같은 안정상으로부터 금속 구리를 제거하는 간접적인 방법으로 제조되고 있다. 고온 고상 반응으로 직접적으로 양극 활물질 Mg2Mo6S8를 제조하는 것이 편리할 것으로 생각되지만 직접적인 방법으로 제조한 Mg2Mo6S8는 표면에 형성된 산화마그네슘(MgO) 산화피막 때문에 전기화학적 활성이 나쁜 것으로 보고되었다. 따라서 Cu2Mo6S8와 같은 안정상을 제조하여 금속 구리를 탈리시키고 다시 그 자리에 마그네슘을 채우는 방법이 Mg2Mo6S8 양극 활물질 제조에 사용되고 있다.On the other hand, the Chevrel phase is thermodynamically metastable, and thus is manufactured by an indirect method of removing metallic copper from a stable phase such as Cu 2 Mo 6 S 8 . It may be convenient to prepare the positive electrode active material Mg 2 Mo 6 S 8 directly by the high temperature solid-state reaction, but the Mg 2 Mo 6 S 8 prepared by the direct method has electrochemical activity due to the magnesium oxide (MgO) oxide film formed on the surface. Reported bad. Therefore, a method of preparing a stable phase such as Cu 2 Mo 6 S 8 to remove metal copper and refilling magnesium in place is used to prepare Mg 2 Mo 6 S 8 cathode active material.
본 발명은 쉐브렐 구조의 마그네슘 이차전지용 양극활물질의 새로운 제조 방법에 관한 것으로서, 입자의 크기가 나노 사이즈로 제어된 쉐브렐 구조의 마그네슘 이차전지용 양극활물질의 제조 방법을 제공하는 것을 목적으로 한다.The present invention relates to a new method for producing a cathode active material for chevron structure magnesium secondary battery, and to provide a method for producing a cathode active material for chevron structure magnesium particles of which the particle size is controlled to a nano size.
본 발명은 또한, 본 발명의 제조 방법에 의하여 제조된 마그네슘 이차전지용 양극활물질을 제공하는 것을 목적으로 한다.Another object of the present invention is to provide a cathode active material for magnesium secondary batteries produced by the production method of the present invention.
본 발명은 상기와 같은 과제를 해결하기 위하여 The present invention to solve the above problems
i)A 원소 화합물, Mo 원소 화합물 및 X 원소 화합물을 화학양론비로 혼합하고, Mechano Fusion 장치에서 에너지를 가하여 교반하는 단계;i) mixing the A element compound, the Mo element compound and the X element compound in a stoichiometric ratio, adding energy and stirring in a Mechano Fusion apparatus;
ii)상기 혼합물을 열처리하여 아래 화학식 1로 표시되는 화합물을 합성하는 단계; 및 ii) heat treating the mixture to synthesize a compound represented by Chemical Formula 1 below; And
[화학식 1] AMo6X8 [Formula 1] AMo 6 X 8
iii)상기 화학식 1의 화합물에서 A를 제거하고 Mg 이온을 삽입하여, 아래 화학식 2로 표시되는 화합물을 합성하는 단계;iii) removing A from the compound of Formula 1 and inserting Mg ions to synthesize a compound represented by Formula 2 below;
[화학식 2] MgyMo6X8 (X = S, Se, 0≤y≤2) Mg y Mo 6 X 8 (X = S, Se, 0≤y≤2)
를 포함하는 마그네슘 이차전지용 양극활물질의 제조 방법을 제공한다. It provides a method for producing a cathode active material for magnesium secondary battery comprising a.
본 발명에 있어서, 상기 Mo 화합물은 예를 들어 산화몰리브덴 일 수 있고, X 원소 화합물은 예를 들어 이황화탄소, 황화수소, 셀레늄화수소, 셀레늄화수소 일 수 있다. In the present invention, the Mo compound is for example molybdenum oxide The elemental X compound may be, for example, carbon disulfide, hydrogen sulfide, hydrogen selenide, hydrogen selenide.
본 발명에 있어서, 상기 A 원소는 와이코프 위치(wyckoff position) 18f 를 점유하고 있으며, Cu, Fe, Co, Ni, Cd, Zn, Mn, 및 Ag 로 이루어진 그룹에서 선택되는 것으로, 상기 A 원소 화합물은 예를 들어 산화구리, 산화철, 산화코발트, 망간아세테이트 등 일 수 있다. In the present invention, the element A occupies a wyckoff position 18f, and is selected from the group consisting of Cu, Fe, Co, Ni, Cd, Zn, Mn, and Ag. Silver may be, for example, copper oxide, iron oxide, cobalt oxide, manganese acetate and the like.
본 발명에 있어서, 상기 와이코프 위치는 Ralph W.G. Wyckoff에 의해 공간 그룹의 이론 결과를 분석한 것으로, 결정학의 국제적 표의 기원에 해당한다. 공간 그룹의 와이코프 위치에 의할 때, 결정 그룹의 와이코프 위치에서 '위치'는 평사도법(stereographic projection)내 결정의 위치를 의미한다. 공간 그룹이 같은 경우, 결정 그룹도 각각 와이코프 위치를 와이코프 문자로 기재하며, 이에 따르면 상기 A원소는 18f 위치를 점유하는 것을 특징으로 한다. In the present invention, the Wycope position is Ralph W.G. An analysis of the theoretical results of the spatial group by Wyckoff, the origin of the international table of crystallography. By the Wykov position of the spatial group, the 'position' in the Wykov position of the decision group refers to the position of the crystal in the stereographic projection. In the case where the spatial groups are the same, the decision group also describes the Wykov position as the Wyck letter, whereby the element A occupies the 18 f position.
본 발명에 있어서, 상기 i)단계에서는 Mechano fusion 장치에서 입자 크기가 10nm 내지 100nm 가 되도록 교반하는 것을 특징으로 한다. 본 발명의 제조 방법에 있어서, 에너지를 가하여 교반하여 양극활물질의 입자 크기가 10nm 내지 100nm 범위로 조절됨으로써, 양극활물질이 높은 비표면적을 가지게 되며 이로 인해 입자간 마그네슘 이온의 이동이 용이해진다. In the present invention, the step i) is characterized in that the stirring so that the particle size in the Mechano fusion apparatus 10nm to 100nm. In the manufacturing method of the present invention, the particle size of the positive electrode active material is adjusted to a range of 10 nm to 100 nm by applying energy and stirring, whereby the positive electrode active material has a high specific surface area, thereby facilitating the transfer of magnesium ions between particles.
본 발명에 있어서, 상기 Mechano fusion 장치는 고에너지 볼 밀(high energy ball mill), 유성 밀(planetary mill), 교반 볼 밀(stirred ball mill) 또는 진동 밀(vibrating mill)인 것을 특징으로 한다. In the present invention, the Mechano fusion apparatus is characterized in that the high energy ball mill (high energy ball mill), planetary mill (planetary mill), stirred ball mill (stirred ball mill) or vibrating mill (vibrating mill).
본 발명의 제조 방법에 있어서, 상기 ii)단계에서는 상기 i) 단계의 혼합물을 1000℃ 내지 1200℃에서 20시간 내지 25시간 동안 비활성 분위기에서 열처리하는 것을 특징으로 한다. 비활성 분위기에서 열처리 하는 것은 금속의 산화를 방지하기 위함이며, 비활성 분위기는 예를 들어 아르곤, 질소 분위기일 수 있고, 바람직하게는 아르곤 분위기이다. In the production method of the present invention, the step ii) is characterized in that the mixture of step i) is heat-treated in an inert atmosphere for 20 to 25 hours at 1000 ℃ to 1200 ℃. The heat treatment in an inert atmosphere is to prevent oxidation of the metal, the inert atmosphere may be, for example, argon, nitrogen atmosphere, preferably an argon atmosphere.
본 발명에 있어서, 상기 iii)단계에서는 산화제 존재하에 A 가 탈리되고, 마그네슘 이온이 삽입되는 것을 특징으로 한다. 산화제는 산화 환원 반응에서 자신을 환원되면서 상대 물질을 산화시키는 물질로, A를 탈리시키는 역할을 하며, 질산, 과염소산, 염산 등을 사용할 수 있으며, 바람직하게는 염산을 사용한다.In the present invention, in step iii), A is released in the presence of an oxidizing agent, and magnesium ions are inserted. The oxidizing agent is a substance that oxidizes a counterpart while reducing itself in a redox reaction, and serves to desorb A, and may use nitric acid, perchloric acid, hydrochloric acid, and the like, preferably hydrochloric acid.
본 발명에 있어서, 상기 iii)단계에서는 또 다른 방법으로서 이온교환법에 의하여 A 가 탈리되고, 마그네슘 이온이 삽입되는 것이 가능하다. A를 부분적으로 또는 전체적으로 마그네슘과 치환하는 것이 가능하다. 상기 이온 교환법은 양극활물질 형성 재료를 마그네슘 함유액에 첨가하여 마그네슘 함유액에 함유된 마그네슘과 상기 양극활물질 형성재료를 구성하는 A사이에 이온교환이 발생하는 방법이다. 상기 마그네슘 함유액의 예로는 MgCl2 등을 포함한다. 또한, 본 발명에서 사용되는 마그네슘 함유액은 마그네슘 이차전지에 사용되는 전해액 일 수 있다. 또한 용매로는 Mg(NO3)2 등을 사용하는 것이 가능하다. In the present invention, in step iii), as another method, A may be detached by ion exchange and magnesium ions may be inserted. It is possible to replace A with magnesium in part or in whole. The ion exchange method is a method in which ion exchange occurs between magnesium contained in the magnesium-containing liquid and A constituting the cathode active material-forming material by adding the positive electrode active material forming material to the magnesium-containing liquid. Examples of the magnesium containing liquid include MgCl 2 and the like. In addition, the magnesium-containing liquid used in the present invention may be an electrolyte solution used in the magnesium secondary battery. As the solvent, it is possible to use Mg (NO 3 ) 2 or the like.
이온교환법에 의해 이온 교환을 진행시키는 방법의 일 예로 열을 이용할 수 있다. 열을 이용하는 방법은, 양극활물질 형성재료가 마그네슘 함유액에 첨가되고, 가열됨으로써 이온 교환 반응이 진행되는 방법이다. 열의 이용은 양호한 이온 교환 반응을 단기간에 수행하게 할 수 있다. 가열 온도는 통상적으로 300 내지 400℃이고, 330 내지 350℃가 바람직하다. 가열 시간은 통상적으로 1 내지 10시간이고, 2 내지 5시간이 바람직하다. Heat may be used as an example of a method of advancing ion exchange by an ion exchange method. The method using heat is a method in which an ion exchange reaction proceeds by adding a positive electrode active material forming material to a magnesium-containing liquid and heating it. The use of heat can result in good ion exchange reactions being carried out in a short time. Heating temperature is 300-400 degreeC normally, and 330-350 degreeC is preferable. The heating time is usually 1 to 10 hours, preferably 2 to 5 hours.
본 발명은 또한, 본 발명의 제조 방법에 의하여 제조되고, 하기 화학식 2 로 표시되는 마그네슘 이차전지용 양극활물질을 제공한다. The present invention also provides a cathode active material for a magnesium secondary battery prepared by the production method of the present invention and represented by the following general formula (2).
[화학식 2] MgyMo6X8 (X = S, Se, 0≤y≤2) MgyMo 6 X 8 (X = S, Se, 0≤y≤2)
본 발명에 있어서, 상기 마그네슘 이차전지용 양극활물질은 쉐브렐 구조이고, 전기화학적 방법 또는 화학적 방법으로 마그네슘 이온이 삽입/탈리되는 것을 특징으로 한다. In the present invention, the cathode active material for magnesium secondary battery has a Chevrel structure, characterized in that the magnesium ion is inserted / detached by an electrochemical method or a chemical method.
본 발명의 제조 방법에 의하여 제조된 상기 양극활물질은 직경이 10 nm 이상 500 nm 이하인 입자로 구성되는 것을 특징으로 한다. 본 발명의 제조 방법은 입자의 크기가 이와 같은 범위로 조절됨으로써 높은 비표면적을 가지게 되며 이로 인해 입자간 마그네슘 이온의 이동이 용이해진다.The cathode active material produced by the production method of the present invention is characterized by consisting of particles of 10 nm or more and 500 nm or less in diameter. The production method of the present invention has a high specific surface area by controlling the size of the particles in such a range, thereby facilitating the transfer of magnesium ions between particles.
본 발명에 있어서, 상기 양극활물질에 마그네슘 이온을 삽입할 때 필요한 활성화 에너지는 0.4 - 0.6 eV 이고, 이때 발생하는 전기화학 전지의 전압이 1.0 - 1.2 V 영역에서 나타나는 것을 특징으로 한다. 상기 활성화 에너지란, 마그네슘을 삽입하는데 필요한 최소한의 에너지로 Mo6S8에서는 0.6eV, Mo6Se8에서는 0.4 eV를 가질 수 있다.In the present invention, the activation energy required to insert magnesium ions into the positive electrode active material is 0.4-0.6 eV, characterized in that the voltage of the electrochemical cell generated at this time appears in the 1.0-1.2 V region. The activation energy is, with a minimum of energy required to insert the magnesium Mo 6 S 8 0.6eV, Mo 6 Se 8 In may have a 0.4 eV.
본 발명에 있어서, 상기 양극활물질은, 상기 y 값이 0 또는 2 인 경우 single phase 이고, y 값이 0 내지 2 인 경우 two phase 인 것을 특징으로 한다. 즉, 본 발명에 있어서, 상기 양극활물질은 y 값이 0 에서 2 까지 변화함에 따라, 즉, 마그네슘 이온이 삽입됨에 따라 single phase -> two phase -> single phase로 상변화가 나타나는 것을 특징으로 한다. In the present invention, the positive electrode active material is a single phase when the y value is 0 or 2, it is characterized in that the two phase when the y value is 0 to 2. That is, in the present invention, the positive electrode active material is characterized in that the phase change occurs in a single phase-> two phase-> single phase as the y value is changed from 0 to 2, that is, magnesium ions are inserted.
본 발명에 있어서, 상기 y 값이 0 또는 2 인 경우 single phase 와 y 값이 0 내지 2 인 경우 two phase 는 rombohedral 의 R-3 공간군에 속하고, 서로 다른 격자 상수를 가지는 것을 특징으로 한다. rombohedral은 하기와 같은 형태의 입방정계로 간주할 수 있다. In the present invention, when the y value is 0 or 2, the single phase and when the y value is 0 to 2, the two phases belong to the R-3 space group of the rombohedral and have different lattice constants. Rombohedral can be regarded as a cubic system of the form
Figure PCTKR2013006489-appb-I000001
Figure PCTKR2013006489-appb-I000001
본 발명은 또한, 본 발명에 의하여 제조되고 입자 사이즈가 나노 크기로 제어된 쉐브렐 구조의 마그네슘 양극활물질을 포함하는 마그네슘 이차전지를 제공한다. The present invention also provides a magnesium secondary battery prepared by the present invention and including a magnesium cathode active material having a chevron structure whose particle size is controlled to a nano size.
본 발명에 의한 입자 사이즈가 나노 크기로 제어된 쉐브렐 구조의 마그네슘 양극활물질을 포함하는 마그네슘 이차전지의 전압은 1.0 내지 1.2V 인 것을 특징으로 한다.The voltage of the magnesium secondary battery including the magnesium cathode active material of the Chevrel structure whose particle size is controlled by nano size according to the present invention is 1.0 to 1.2V.
본 발명에 의한 마그네슘 이차전지는 양극, 음극, 바인더를 포함한다. 본 발명에 있어서, 상기 양극은 본 발명에 의한 양극활물질, 및 바인더 또는 도전재를 추가로 포함할 수 있다. Magnesium secondary battery according to the present invention includes a positive electrode, a negative electrode, a binder. In the present invention, the positive electrode may further include a positive electrode active material, and a binder or a conductive material according to the present invention.
상기 도전재는 마그네슘 이차전지에 사용되는 어떠한 것도 사용할 수 있다. 도전재의 예로 천연 흑연, 인조 흑연, 카본 블랙, 아세틸렌 블랙, 케첸 블랙, 탄소섬유 등의 탄소계 물질; 구리, 니켈, 알루미늄 및 은과 같은 금속 분말이나 금속 섬유; 폴리페닐렌 유도체와 같은 도전성 재료; 또는 이들의 조합을 사용할 수 있다. The conductive material may be used for anything used in the magnesium secondary battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, and carbon fiber; Metal powder or metal fibers such as copper, nickel, aluminum and silver; Conductive materials such as polyphenylene derivatives; Or combinations thereof.
상기 바인더는 양극활물질 입자를 잘 부착시키고, 또한 양극활물질을 전류 집전체에 잘 부착시키는 역할을 한다. 상기 바인더의 대표적인 예로는 폴리비닐알콜, 카르복시메틸셀룰로즈, 히드록시프로필셀룰로즈, 디아세틸셀룰로즈, 폴리비닐클로라이드, 카르복실화된 폴리비닐클로라이드, 폴리비닐플루오라이드, 에틸렌 옥사이드를 포함하는 폴리머, 폴리비닐피롤리돈, 폴리우레탄, 폴리테트라플루오로에틸렌, 폴리비닐리덴 플루오라이드, 폴리에틸렌, 폴리프로필렌, 스티렌-부타디엔 러버, 아크릴레이티드 스티렌-부타디엔 러버, 에폭시수지, 나일론 또는 이들의 조합을 사용할 수 있다.The binder adheres well to the positive electrode active material particles, and also serves to adhere the positive electrode active material to the current collector. Representative examples of the binder include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinylchloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpi Ralidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resins, nylon or combinations thereof may be used.
상기 양극은, 양극 형성용 재료 자체를 일정한 모양으로 성형하거나, 상기 양극 형성용 재료를 구리 포일(Copper Foil), 니켈 포일(Nickel Foil) 또는 스테인레스 강 포일(Stainless Steel Foil)과 같은 집전체 위에 도포하는 방법에 의해 제조할 수 있다. The anode may be formed in a shape of the anode forming material itself, or the anode forming material is coated on a current collector such as copper foil, nickel foil, or stainless steel foil. It can manufacture by the method of doing.
본 발명의 마그네슘 이차전지에 있어서, 상기 음극은 마그네슘 단일 물질 및 마그네슘을 함유하는 합금으로 이루어진 군으로부터 선택되는 하나 이상일 수 있다. 예를 들어, 상기 음극은 마그네슘 디스크 일 수 있다. In the magnesium secondary battery of the present invention, the negative electrode may be at least one selected from the group consisting of a magnesium single material and an alloy containing magnesium. For example, the cathode may be a magnesium disk.
본 발명의 마그네슘 이차전지는 전해질을 더 포함한다. 상기 전해질은 마그네슘 이온 함유 비수전해질일 수 있다. 예를 들어, 상기 전해질은 테트라하이드로퓨란(THF)와 같은 유기용매에 Mg(AlCl2EtBu)2와 같은 마그네슘 염을 녹인 용액일 수 있다. 상기 화학식 [Mg(AlCl2EtBu)2]에서 Et는 에틸기이고, Bu는 부틸기이다.The magnesium secondary battery of the present invention further includes an electrolyte. The electrolyte may be a magnesium ion-containing nonaqueous electrolyte. For example, the electrolyte may be a solution in which a magnesium salt such as Mg (AlCl 2 EtBu) 2 is dissolved in an organic solvent such as tetrahydrofuran (THF). In the formula [Mg (AlCl 2 EtBu) 2 ], Et is an ethyl group and Bu is a butyl group.
본 발명에 있어서, 상기 마그네슘 이차전지는 상기 양극과 상기 음극을 물리적으로 및 전기적으로 서로 분리시키는 세퍼레이터를 추가로 포함할 수 있다. 상기 세퍼레이터는 마그네슘 전지에 통상적으로 사용되는 것일 수 있다. 이러한 세퍼레이터는 유리필터, 폴리에스테르, 테프론, 폴리에틸렌, 폴리프로필렌, 폴리테트라플루오르에틸렌(PTFE) 또는 이들의 조합일 수 있다. 또한, 이러한 세퍼레이터는 직포 또는 부직포 형태일 수 있다.In the present invention, the magnesium secondary battery may further include a separator that physically and electrically separates the positive electrode and the negative electrode from each other. The separator may be one commonly used in magnesium batteries. Such a separator may be a glass filter, polyester, teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) or a combination thereof. In addition, such a separator may be in the form of a woven fabric or a nonwoven fabric.
본 발명에 의한 마그네슘 이차전지용 양극활물질의 제조 방법은 원료 화합물을 혼합시 입자 크기를 조절함으로써 낮은 온도에서도 불순물이 형성되지 않도록 할 뿐만 아니라, 본 발명의 제조 방법에 의하여 제조된 쉐브렐 구조의 양극활물질은 마그네슘 이온의 삽입 탈리가 용이하게 되어 마그네슘 이차 전지 내에서 마그네슘 이온의 확산을 향상시키는 효과가 있다.The method for manufacturing a cathode active material for magnesium secondary battery according to the present invention not only prevents impurities from being formed even at a low temperature by adjusting the particle size when mixing the raw material compounds, and has a chevron structure cathode active material manufactured by the manufacturing method of the present invention. Insertion and desorption of silver magnesium ions is facilitated, thereby improving the diffusion of magnesium ions in the magnesium secondary battery.
도 1은 본 발명에 의한 마그네슘 이차전지용 양극활물질의 제조 방법을 나타내는 모식도이다. 1 is a schematic diagram showing a method for producing a cathode active material for magnesium secondary battery according to the present invention.
도 2는 본 발명의 일 실시예에 의하여 제조된 마그네슘 이차전지용 양극활물질의 X선 회절 패턴을 나타낸다.Figure 2 shows the X-ray diffraction pattern of the positive electrode active material for magnesium secondary battery prepared according to an embodiment of the present invention.
도 3은 본 발명의 일 실시예 및 비교예에 의하여 제조된 마그네슘 이차전지용 양극활물질의 SEM 사진을 나타낸다. Figure 3 shows a SEM photograph of the positive electrode active material for magnesium secondary battery prepared by one embodiment and comparative example of the present invention.
도 4는 본 발명의 본 발명의 일 실시예 및 비교예에 의하여 제조된 마그네슘 이차전지용 양극활물질을 포함하는 마그네슘 이차 전지의 충방전 곡선을 나타낸다. Figure 4 shows the charge and discharge curve of the magnesium secondary battery comprising a cathode active material for magnesium secondary battery prepared according to an embodiment and a comparative example of the present invention.
도 5는 본 발명의 본 발명의 일 실시예 및 비교예에 의하여 제조된 마그네슘 이차전지용 양극활물질을 포함하는 마그네슘 이차 전지의 출력특성 그래프를 나타낸다.FIG. 5 is a graph illustrating output characteristics of a magnesium secondary battery including a cathode active material for magnesium secondary battery manufactured according to an embodiment and a comparative example of the present invention.
이하에서는 실시예에 의하여 본 발명을 더욱 상세히 설명한다. 그러나, 본 발명이 아래의 실시예에 의하여 한정되는 것은 아니다. Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited by the following examples.
<실시예 1> 마그네슘 양극활물질의 합성Example 1 Synthesis of Magnesium Cathode Active Material
출발 물질인 A 원소 화합물로서 Cu, Mo 원소 화합물 및 X 원소로서 S을 혼합하고, 고에너지밀링기(High energy milling machine) 6시간 동안 480 rpm 으로 교반하였다. 이후, Swagelok 반응기 내에 위치시킨 후 1100℃ 에서 아르곤(Ar) 가스 분위기에서 24시간 동안 열처리시켜 Cu2.5Mo6S8로 표시되는 화합물을 합성하였다. 이후 HCl을 산화제로 사용하여 상기 Cu2.5Mo6S8로부터 구리 원소를 탈리시켜 Mo6S8 입자를 형성하였다. Cu, Mo element compound and S as X element were mixed as starting material A element compound, and it stirred at 480 rpm for 6 hours for High energy milling machine. Subsequently, the compound represented by Cu 2.5 Mo 6 S 8 was synthesized by placing it in a Swagelok reactor and heat-treating at 1100 ° C. for 24 hours in an argon (Ar) gas atmosphere. Thereafter, copper was desorbed from the Cu 2.5 Mo 6 S 8 using HCl as an oxidant to form Mo 6 S 8 particles.
<비교예 1> 마그네슘 양극활물질의 합성Comparative Example 1 Synthesis of Magnesium Cathode Active Material
A 원소 화합물로서 Cu, Mo 원소 화합물 및 X 원소로서 S을 유발에 담고 mechno fusion 장치가 아니라, Hand mixing을 30분 동안 실시한 이후, Swagelok 반응기 내에 위치시킨 후 1100℃ 에서 아르곤(Ar) 가스 분위기에서 24시간 동안 열처리시켜 Cu2.5Mo6S8로 표시되는 마그네슘 양극활물질을 합성하였다. 이후 HCl을 산화제로 사용하여 상기 Cu2.5Mo6S8로부터 구리 원소를 탈리시켜 상기 [화학식 2]MgyMo6X8 에서 y =0 인 Mo6S8 입자를 형성하였다. Cu, Mo element compound as element A and S element as element X were added to the induction, and after hand mixing for 30 minutes rather than a mechno fusion device, placed in a Swagelok reactor and then placed in an argon (Ar) gas atmosphere at 1100 ° C. Heat treatment for a time to synthesize a magnesium cathode active material represented by Cu 2.5 Mo 6 S 8 . Thereafter, copper was desorbed from the Cu 2.5 Mo 6 S 8 by using HCl as an oxidizing agent, thereby forming Mo 6 S 8 particles having y = 0 in Mg y Mo 6 X 8 .
<실험예 1> SEM 사진의 측정Experimental Example 1 Measurement of the SEM Photograph
상기 실시예 1 및 비교예 1에서 제조된 양극활물질의 SEM 사진을 측정하고 그 결과를 도 1에 나타내었다. 도 1에서 비교예 1의 양극활물질은 1차 입자의 크기가 평균 2μm 인 것에 반하여, 실시예 1은 1차 입자의 크기가 나노 크기 즉, 500nm 이하로 제어된 것을 확인할 수 있었다. SEM pictures of the cathode active materials prepared in Example 1 and Comparative Example 1 were measured and the results are shown in FIG. 1. In FIG. 1, the cathode active material of Comparative Example 1 had an average size of primary particles of 2 μm, whereas in Example 1, the size of primary particles was controlled to a nano size, that is, 500 nm or less.
<실험예 2> XRD 패턴의 측정Experimental Example 2 Measurement of XRD Pattern
상기 실시예 1에서 제조된 Cu2.5Mo6S8 와 화학적으로 Cu가 탈리된 Mo6S8의 X선 회절 패턴을 도 2에 나타내었다. 도 2에서 본 발명의 실시예에서 제조된 활물질의 경우 불순물을 포함하지 않는 단일상의 쉐브렐 구조의 Mo6S8임을 확인할 수 있었다.An X-ray diffraction pattern of the above-described Cu 2.5 Mo 6 S 8 and chemically the Cu Mo 6 S 8 tally prepared in Example 1 is shown in Fig. It was confirmed that even if the active material is manufactured in an embodiment of the present invention in the second single guilloche structure beurel Mo 6 S 8 on the containing no impurities.
<실시예 2> 양극의 제조Example 2 Fabrication of Positive Electrode
상기 실시예 1, 및 비교예 1 에서 제조된 Mo6S8의 활물질을 포함하는 양극을 제조하였다. A positive electrode including the active material of Mo 6 S 8 prepared in Example 1 and Comparative Example 1 was prepared.
상기 실시예 1, 비교예 1 에서 제조된 양극활물질 80 중량부, 도전재로 덴카블랙 10 중량부 및 바인더로 폴리비닐리덴 플루오라이드(PVDF) 10 중량부를 혼합하였다. 상기 혼합물을 N-메틸-피롤리돈(NMP)에 분산시켜 양극 형성용 슬러리를 제조하였다. 이후, 10μm두께의 스테인레스 강 포일 위에 상기 슬러리를 70㎛ 두께로 코팅하고 건조한 후 120℃의 롤압착기(roll press machine)로 20-25%의 압착률로 압착하여 양극을 제조하였다. 80 parts by weight of the positive electrode active material prepared in Example 1 and Comparative Example 1, 10 parts by weight of denca black as a conductive material and 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder were mixed. The mixture was dispersed in N-methyl-pyrrolidone (NMP) to prepare a slurry for positive electrode formation. Thereafter, the slurry was coated to a thickness of 70 μm on a stainless steel foil having a thickness of 10 μm, dried, and pressed at a compression ratio of 20-25% using a roll press machine at 120 ° C. to prepare a positive electrode.
<실시예 3> 전지의 제조Example 3 Fabrication of Battery
상기 실시예 2로부터 제조된 마그네슘 이차전지용 양극과, 음극으로 마그네슘 디스크, 세퍼레이터를 사용하여 코인셀을 제작하였다. A coin cell was manufactured using a magnesium secondary battery positive electrode prepared in Example 2 and a magnesium disc and a separator as a negative electrode.
코인셀은 2032 규격으로, 세퍼레이터로는 유리필터(Whatman, GF/F)를 사용하였고, 전해질로는 테트라하이드로퓨란(THF)에 0.4M (PhMgCl:AlCl3Et = 2:1)의 염을 함유하는 전해액을 주입하였다.Coin cell is 2032 standard, glass filter (Whatman, GF / F) is used as separator, and tetrahydrofuran (THF) is used as electrolyte and contains 0.4M (PhMgCl: AlCl 3 Et = 2: 1) salt. An electrolyte solution was injected.
<실험예 3> 전지 용량 특성 측정Experimental Example 3 Measurement of Battery Capacity Characteristics
상기 실시예 3에서 제조된 코인셀에 대해서 초기 3회 충방전 측정하고, 그 결과를 도 4에 나타내었다. The coin cell prepared in Example 3 was initially charged and discharged three times, and the results are shown in FIG. 4.
도 4에서 보는 바와 같이 실시예 1의 양극활물질을 포함하는 전지의 경우 초기 포메이션을 실시한 후 2번째 사이클의 방전용량이 88 mAh/g의 용량을 나타내었다. 이에 비해 비교예 1의 양극활물질로 제조된 전지는 69 mAh/g을 나타내었다. 특히 충방전 곡선으로부터 고찰하면 비교예 1 대비 실시예 1의 용량 증가는 방전 초기 1.3V 부근의 초기 방전 평탄면 영역의 용량이 증가함에 기인하는 것을 알 수 있다. As shown in FIG. 4, in the case of the battery including the cathode active material of Example 1, the discharge capacity of the second cycle after the initial formation was about 88 mAh / g. In comparison, a battery made of the cathode active material of Comparative Example 1 exhibited 69 mAh / g. In particular, considering the charge and discharge curves, it can be seen that the increase in the capacity of Example 1 compared to Comparative Example 1 is due to the increase in the capacity of the initial discharge flat surface region near the initial 1.3V discharge.
<실험예 4> 전지 출력 특성 측정Experimental Example 4 Measurement of Battery Output Characteristics
상기 실시예 3에서 제조된 실시예 1 및 비교예 1의 마그네슘 이차전지용 양극을 포함하는 코인셀에 대해서 C-rate를 0.05, 0.1, 0.2, 0.5, 1, 2, 5C로 하여 출력 특성을 측정하고, 그 결과를 도 5에 나타내었다. 도 5에서 실시예 1은 방전용량 유지율을 초기 0.05 C 대비 5C에서 95.6% 인데 비해, 비교예 1은 55.3%를 나타내었으며, 이로부터 본 발명에 의하여 1차 입자 크기가 제어됨으로써 출력특성이 현저히 개선됨을 확인할 수 있었다.For the coin cell including the magnesium secondary battery positive electrode of Example 1 and Comparative Example 1 prepared in Example 3 by measuring the output characteristics to 0.05, 0.1, 0.2, 0.5, 1, 2, 5C The results are shown in FIG. 5. In FIG. 5, the discharge capacity retention rate of Example 1 was 95.6% at 5C compared to the initial 0.05 C. In Comparative Example 1, 55.3% was shown. From this, the primary particle size was controlled by the present invention, thereby significantly improving the output characteristics. Could confirm.
이상 설명한 바와 같이, 본 발명에 의한 마그네슘 이차전지용 양극활물질의 제조 방법은 원료 화합물을 혼합시 입자 크기를 조절함으로써 낮은 온도에서도 불순물이 형성되지 않도록 할 뿐만 아니라, 본 발명의 제조 방법에 의하여 제조된 쉐브렐 구조의 양극활물질은 마그네슘 이온의 삽입 탈리가 용이하게 되어 마그네슘 이차 전지 내에서 마그네슘 이온의 확산을 향상시키는 효과가 있다.As described above, the method for producing a cathode active material for magnesium secondary battery according to the present invention not only prevents impurities from being formed even at low temperatures by controlling the particle size when mixing the raw material compounds, and is prepared by the method of the present invention. The cathode active material of the Brel structure facilitates the insertion and removal of magnesium ions, thereby improving the diffusion of magnesium ions in the magnesium secondary battery.

Claims (15)

  1. i) A 원소 화합물, Mo 원소 화합물 및 X 원소 화합물을 화학양론비로 혼합하고, Mechano Fusion 장치에서 에너지를 가하여 교반하는 단계;i) mixing the A element compound, the Mo element compound and the X element compound in a stoichiometric ratio, adding energy and stirring in a Mechano Fusion apparatus;
    ii)상기 혼합물을 열처리하여 아래 화학식 1로 표시되는 화합물을 합성하는 단계; 및 ii) heat treating the mixture to synthesize a compound represented by Chemical Formula 1 below; And
    [화학식 1] AMo6X8 [Formula 1] AMo 6 X 8
    (상기 화학식 1에서 X = S, 또는 Se 이고, A 는 Cu, Fe, Co, Ni, Cd, Zn, Mn, 및 Ag 로 이루어진 그룹에서 선택되는 원소임)(In Formula 1, X = S, or Se, and A is an element selected from the group consisting of Cu, Fe, Co, Ni, Cd, Zn, Mn, and Ag.)
    iii)상기 화학식 1의 화합물에서 A를 제거하고 Mg 이온을 삽입하여, 아래 화학식 2로 표시되는 화합물을 합성하는 단계;를 포함하는 마그네슘 이차전지용 양극활물질의 제조 방법. iii) removing the A from the compound of Formula 1 and inserting Mg ions to synthesize a compound represented by the following Formula 2. A method of manufacturing a cathode active material for magnesium secondary battery comprising a.
    [화학식 2] MgyMo6X8 (X = S, Se, 0≤y≤2) Mg y Mo 6 X 8 (X = S, Se, 0≤y≤2)
  2. 제 1 항에 있어서, The method of claim 1,
    상기 A 원소는 와이코프 위치(wyckoff position) 18f 를 점유하고 있으며, Cu, Fe, Co, Ni, Cd, Zn, Mn, 및 Ag 로 이루어진 그룹에서 선택되는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.The element A occupies a wyckoff position 18f, and is prepared from a group consisting of Cu, Fe, Co, Ni, Cd, Zn, Mn, and Ag. Way.
  3. 제 1 항에 있어서, The method of claim 1,
    상기 i)단계에서는 입자 크기가 10nm 내지 100nm 가 되도록 교반하는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.In step i), the method of manufacturing a cathode active material for magnesium secondary battery, characterized in that the particle size is stirred so that the 10nm to 100nm.
  4. 제 1 항에 있어서, The method of claim 1,
    상기 Mechano fusion 장치는 고에너지 볼 밀, 유성 밀, 교반 볼 밀 또는 진동 밀인 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.The Mechano fusion device is a high energy ball mill, a planetary mill, a stirring ball mill or a vibration mill manufacturing method of the positive electrode active material for magnesium secondary battery, characterized in that.
  5. 제 1 항에 있어서, The method of claim 1,
    상기 ii)단계에서는 상기 i)단계의 혼합물을 1000℃ 내지 1200℃에서 20시간 내지 25시간 동안 비활성 분위기에서 열처리하는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.In step ii), the mixture of step i) is heat-treated at 1000 ° C. to 1200 ° C. for 20 to 25 hours in an inert atmosphere.
  6. 제 1 항에 있어서, The method of claim 1,
    상기 iii)단계에서는 산화제 존재 하에 A가 탈리되고, Mg 이온이 삽입되는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.In step iii), A is desorbed in the presence of an oxidant, Mg ion is inserted, characterized in that the manufacturing method of the positive electrode active material for magnesium secondary battery.
  7. 제 1 항에 있어서, The method of claim 1,
    상기 iii)단계에서는 이온교환법에 의하여 A가 탈리되고, Mg 이온이 삽입되는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질의 제조 방법.In step iii), A is desorbed by ion exchange and Mg ions are inserted into the cathode active material for magnesium secondary battery.
  8. .제 1 항 내지 제 7 항 중 어느 하나의 제조 방법에 의하여 제조되고, 하기 화학식 2 로 표시되는 마그네슘 이차전지용 양극활물질. A cathode active material for magnesium secondary batteries, which is prepared by the method of any one of claims 1 to 7 and is represented by the following general formula (2).
    [화학식 2] MgyMo6X8 (X = S, Se, 0≤y≤2) Mg y Mo 6 X 8 (X = S, Se, 0≤y≤2)
  9. 제 8 항에 있어서, The method of claim 8,
    상기 양극활물질은 직경이 10nm 이상 500nm 이하인 것을 특징으로 하는 마그네슘 이차전지용 양극활물질.The cathode active material is a cathode active material for magnesium secondary battery, characterized in that the diameter is more than 10nm 500nm.
  10. 제 8 항에 있어서, The method of claim 8,
    상기 양극활물질은 쉐브렐 구조이고, 전기화학적 방법 또는 화학적 방법으로 마그네슘 이온이 삽입/탈리되는 것인 마그네슘 이차전지용 양극활물질. The cathode active material is a Chevrel structure, and the magnesium active battery positive electrode active material that is inserted / desorbed by the electrochemical method or chemical method.
  11. 제 8 항에 있어서, The method of claim 8,
    상기 양극활물질에 마그네슘 이온을 삽입할 때 필요한 활성화 에너지는 0.4 내지 0.6 eV인 것을 특징으로 하는 마그네슘 이차전지용 양극활물질.The activation energy required when inserting magnesium ions into the cathode active material is a cathode active material for magnesium secondary battery, characterized in that 0.4 to 0.6 eV.
  12. 제 8 항에 있어서, The method of claim 8,
    상기 y 값이 0 또는 2 인 경우 single phase 이고, y 값이 0 내지 2 인 경우 two phase 인 것을 특징으로 하는 마그네슘 이차전지용 양극활물질.The positive electrode active material for magnesium secondary battery, characterized in that the y value is 0 or 2 is a single phase, if the y value is 0 to 2 two phase.
  13. 제 12 항에 있어서, The method of claim 12,
    상기 single phase 와 two phase 는 rombohedral 의 R-3 공간군에 속하고, 서로 다른 격자 상수를 가지는 것을 특징으로 하는 마그네슘 이차전지용 양극활물질. The single phase and two phase belong to the R-3 space group of the rombohedral, the cathode active material for magnesium secondary battery, characterized in that it has a different lattice constant.
  14. 제 8 항에 의한 마그네슘 이차전지용 양극활물질을 포함하는 마그네슘 이차 전지.A magnesium secondary battery comprising the cathode active material for magnesium secondary battery according to claim 8.
  15. 제 13 항에 있어서, The method of claim 13,
    상기 마그네슘 이차 전지의 전압은 1.0 - 1.2 V 인 것을 특징으로 하는 마그네슘 이차 전지.Magnesium secondary battery, the voltage of the magnesium secondary battery, characterized in that 1.0 to 1.2V.
PCT/KR2013/006489 2012-07-19 2013-07-19 Method for preparing positive electrode active material for magnesium secondary battery and positive electrode active material for magnesium secondary battery prepared by the method WO2014014311A1 (en)

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