WO2017217685A1 - Magnesium secondary battery - Google Patents

Abstract

The present invention relates to a magnesium secondary battery capable of operating at room temperature. Specifically, the magnesium secondary battery according to the present invention comprises, in an as-prepared (as-synthesized) state in which no charging or discharging has been carried out: an anode comprising a transition metal compound as an anode active material; a cathode comprising a Mg-Sn alloy as a cathode active material; and an electrolyte.

Description

Magnesium secondary battery

The present invention relates to a magnesium secondary battery, and more particularly, to a magnesium secondary battery having high efficiency and capable of long-term stable driving.

As the field of application of secondary batteries is expanded to mobile phones, laptops and electric vehicles, demand for higher capacity of energy storage devices is increasing.

Accordingly, as a next-generation secondary battery, it is more environmentally friendly, more stable, richer in resources, and higher in capacity than conventional secondary batteries such as lithium secondary batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel zinc. Research on magnesium secondary battery that can be used as a battery has been made.

A magnesium secondary battery is a secondary battery in which magnesium ions are inserted and detached into a cathode active material and charged and discharged by moving electrons. In the magnesium secondary battery, a magnesium plate as a cathode, a Chevrel-phase cathode active material as a cathode, and a Grignard solution, which is an alkyl magnesium halide electrolyte as an electrolyte, have been attracting attention in terms of commercialization possibility.

Magnesium secondary batteries only began practical research in the 2000s when reversible charging and discharging was secured by Chevrel-phase cathode active materials, and only energy density of less than half of lithium ion batteries is realized. Development of new active material, electrolyte material, current collector, and the like are urgently required.

However, most researches on magnesium secondary batteries are concentrated in the field of electrolytes, such as US Patent No. 6713213 and Japanese Patent Application No. 2007-188709, or in the field of positive electrode active materials, such as Korean Patent Application Publication No. 2015-0033787. Research on the negative electrode active material of the secondary battery is almost insignificant.

An object of the present invention is to provide a magnesium secondary battery having excellent battery capacity and improved cycle characteristics.

Magnesium secondary battery according to the present invention, a positive electrode, Mg-Sn alloy containing a transition metal compound capable of reversible insertion and desorption of magnesium ions as a positive electrode active material in an as-synthesized state, without charge and discharge It includes a cathode and an electrolyte containing (alloy) as a cathode active material.

Magnesium secondary battery according to an embodiment of the present invention can be driven at room temperature. That is, the magnesium secondary battery according to an embodiment of the present invention may be for room temperature, and in this case, the room temperature is a temperature in which a separate thermal energy is not applied to the secondary battery from the outside, for example, a temperature of 10 to 35 ° C. It may mean.

In the magnesium secondary battery according to an embodiment of the present invention, the cathode active material may not contain magnesium. That is, in the magnesium secondary battery according to an embodiment of the present invention, in the as-synthesized state in which charge and discharge are not performed, the cathode active material of the cathode may not contain magnesium.

In the magnesium secondary battery according to an embodiment of the present invention, the cathode active material is scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt ( Oxides, halides, chalcogens of one or more transition metals selected from Co, nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), niobium (Nb), and ruthenium (Ru) It may be a cargo or a cyanide.

Magnesium secondary battery according to an embodiment of the present invention may be in a charged state.

In the magnesium secondary battery according to an embodiment of the present invention, the negative electrode active material may be Mg ₂ Sn.

In the magnesium secondary battery according to an embodiment of the present invention, the negative electrode active material may be made of Mg ₂ Sn particles.

In the magnesium secondary battery according to an embodiment of the present invention, the average diameter of the Mg ₂ Sn particles may be 5nm to 20μm.

In the magnesium secondary battery according to an embodiment of the present invention, the electrolyte may be a non-aqueous electrolyte containing magnesium ions.

The magnesium secondary battery according to an embodiment of the present invention may further include a separator.

Magnesium secondary battery according to the present invention, in the state immediately after the manufacturing without charging and discharging, as the negative electrode contains the Mg-Sn alloy, even if repeated charging and discharging is carried out stably maintain the battery capacity and can have an improved lifetime In addition, there is an advantage of having a very high coulombic efficiency of 99% or more even in 20 charge and discharge cycles.

1 is a view showing the results of X-ray diffraction measurement of Mg ₂ Sn alloy prepared in Example 1 of the present invention,

2 is a view showing the charge and discharge cycle characteristics of the half-cell manufactured in Example 1 of the present invention,

3 is a view showing the capacity (mAh / g) according to the charge and discharge of the complete cell produced in Example 2 of the present invention.

Hereinafter, the magnesium secondary battery of the present invention will be described in detail. At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs, the gist of the present invention in the following description and the accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily blurred are omitted.

In the case of the Sn-based negative electrode, as charging and discharging of the battery are repeated, an alloy of Mg and Sn including Mg ₂ Sn in the negative electrode may be generated by the following Scheme 1 during charging.

(Scheme 1)

^{Sn + 2Mg 2+ + 4e - →} Mg 2 Sn

However, such a Sn-based negative electrode has a problem in that the battery capacity suddenly decreases as the charge and discharge cycle is repeatedly performed.

That is, in the as-fabricated state in which charging and discharging is not performed, when Sn is contained as a negative electrode active material and when magnesiumization and demagnesification of Sn are repeatedly performed in the charging and discharging process, the charging and discharging cycle is substantially performed. Even if only about 10 times, a problem occurs that the battery characteristics are rapidly deteriorated to the extent that it cannot be used as a battery.

Applicant has a large specific surface area and can realize a particle-based negative electrode rather than a plate or thin film-based negative electrode having a large active area in which an electrochemical reaction is performed, difficult to handle, and relatively expensive, and can be easily manufactured at low cost. Much research has been conducted on magnesium secondary batteries that can be driven at room temperature and have stable cycle characteristics for a longer period of time to improve battery life.

As a result, it was found that the state of the negative electrode in the state immediately after the manufacture had a great influence on the electrochemical characteristics of the battery when the battery was driven. When the negative electrode was formed by the Mg-Sn alloy itself, not Sn, The properties have been surprisingly improved, and furthermore, the Coulomb efficiency has also been found to significantly increase, leading to the present application.

Based on the above findings, a magnesium secondary battery according to the present invention includes a positive electrode including a transition metal compound capable of reversible insertion and detachment of magnesium ions as an anode active material in an as-synthesized state in which charging and discharging are not performed. A cathode and an electrolyte including an Mg-Sn alloy as an anode active material are included. In this case, the electrolyte may be located between the positive electrode and the negative electrode.

In detail, the magnesium secondary battery according to the present invention is a cathode and a metal including a transition metal compound capable of reversible insertion and desorption of magnesium ions as an anode active material in an as-synthesized state in which charging and discharging are not performed. It includes a negative electrode and an electrolyte containing no negative electrode active material containing no Sn and Mg-Sn alloy (alloy). That is, the magnesium secondary battery according to the present invention is a cathode including a transition metal compound capable of reversible insertion and detachment of magnesium ions as a cathode active material, Mg-Sn in an as-synthesized state in which charging and discharging are not performed. An anode and an electrolyte including an anode active material made of an alloy (alloy) is included. At this time, the negative electrode active material is made of an Mg-Sn alloy (alloy) means that in addition to the Mg-Sn alloy in the negative electrode there is no other active material (heterogeneous negative electrode active material) involved in charging and discharging.

In the magnesium secondary battery according to an embodiment of the present invention, the Mg-Sn alloy is preferably Mg ₂ Sn. That the negative electrode active material is made of Mg-Sn alloy means that the magnesium secondary battery according to the present invention has a state of charge immediately after manufacture, and furthermore, that the negative electrode active material is made of Mg ₂ Sn, there is no charge and discharge In the immediate post-production state, this means that the battery has the maximum possible state of charge theoretically.

As a theoretically possible maximum state of charge in the state immediately after manufacture, the magnesium secondary battery according to an embodiment of the present invention can be discharged during the initial charge and discharge. When the charge-discharge cycle is repeated with one cycle of discharge-charge, demagnesiumation and magnesiumation may occur repeatedly from the surface of the negative electrode active material in contact with the electrolyte. However, as described above, since the negative electrode of the battery includes a negative electrode active material made of an Mg-Sn alloy, preferably Mg ₂ Sn in a state immediately after manufacture, demagnesiumation and magnesiumation occur repeatedly from the surface region of the negative electrode active material. In the process, the core of the negative electrode active material may continuously serve as a source of magnesium. This means that the magnesium supply profile from the core to the surface can also be made by the magnesium concentration profile of the negative electrode active material itself during charging and / or discharging, which will lead to quick and easy magnesiumation and demagnesification in the surface area of the negative electrode active material. Can be. In addition, when the negative electrode of the battery includes a negative electrode active material made of an Mg-Sn alloy, preferably Mg ₂ Sn in a state immediately after manufacture, the physical structure and electrical characteristics of the electrode even when the negative electrode is repeatedly magnesiumated and demagnesiumated The deformation or deterioration (eg, desorption, etc.) can be prevented. Accordingly, the secondary battery according to an embodiment of the present invention can stably maintain the battery capacity even when performing repeated charge / discharge cycles, have a significantly improved cycle life, have high coulombic efficiency, and have improved high rate characteristics. Can be.

In the secondary battery according to an embodiment of the present invention, the negative electrode active material may be Mg-Sn alloy, preferably Mg ₂ Sn, the negative electrode active material may be made of Mg-Sn alloy particles, preferably Mg ₂ Sn particles. When magnesium metal itself is used as the cathode as in the prior art, magnesium plate (foil) itself is used as the cathode. On the other hand, the secondary battery according to an embodiment of the present invention, the negative electrode active material is a particulate form of Mg-Sn alloy particles, preferably Mg ₂ Sn particles. Accordingly, rolling and / or rolling of the current collector to which the negative electrode active material is applied can improve battery output, and there are advantages in that electrodes can be manufactured in various shapes and structures. In addition, it can be mixed with a conductive material and a binder to form a negative electrode active material layer on the current collector, through which, there is an advantage that can improve the electrical conductivity, physical strength and stability of the negative electrode (current collector and negative electrode active material layer). . In addition, since the negative electrode active material layers may be formed, there is an advantage in that the reaction area with the electrolyte in the same volume may be significantly improved. In addition, there is an advantage that can be applied to the manufacturing process of the magnesium secondary battery without highly changing the existing battery manufacturing technology in the conventional lithium secondary battery, such as slurry production, coating and drying, rolling (rolling).

The average diameter of the Mg-Sn alloy particles, preferably Mg ₂ Sn particles, may be in the order of several nanometers to several tens of micrometers. Mg-Sn alloy particles, preferably Mg ₂ Sn particles, of several nanometers to several tens of micrometers of order, can significantly improve the reaction area with the electrolyte solution while increasing the energy density of the cathode. Strength may be improved and may have improved structural stability during the electrochemical reaction. In addition, Mg-Sn alloy particles, preferably Mg ₂ Sn particles, having orders of several nanometers to several tens of micrometers, may be formed in the particle (center region) in the process of repeatedly demagnesification and magnesiumation from the surface region of the particle during repeated charge and discharge. ) Can continuously supply magnesium to the surface area. Specifically, the average diameter of the Mg-Sn alloy particles, preferably Mg ₂ Sn particles may be 5 nm to 20 ㎛, specifically 1 to 15 ㎛, but is not limited thereto.

In the magnesium secondary battery according to the present invention, the negative electrode of Mg ₂ Sn is a negative electrode active material may satisfy the following equation 1.

(Relationship 1)

Cap (20) / Cap (5) ≥ 0.85

In relation (1), Cap (5) is made of magnesium metal as a counter electrode of a cathode and a cathode, and a coin cell in which tetrahydrofuran (THF) in which PhMgCl (Ph = phenyl) is dissolved at a concentration of 0.5 M is provided as an electrolyte. In the charge and discharge cycle test at a voltage range of -0.6V and 0.2C, the discharge capacity at the fifth cycle, and Cap (20) is the discharge capacity at the 20th cycle in the same coin cell.

In the magnesium secondary battery according to the present invention, the negative electrode of Mg ₂ Sn is a negative electrode active material may satisfy the following equation (2) and (3).

(Relationship 2)

 CE (1) ≥ 85%

In relation 2, CE (1) is a coin cell in which a magnesium metal is provided as a counter electrode of the cathode and the cathode, and tetrahydrofuran (THF) in which PhMgCl (Ph = phenyl) is dissolved at a concentration of 0.5 M is provided as an electrolyte. Initial (first) coulombic efficiency (%) in a voltage range of 0.05V-0.6V and charge / discharge cycle testing at 0.2C.

(Relationship 3)

CE (20) ≥ 95%

In the relation 3, CE (20) has a coin cell in which magnesium metal is provided as a counter electrode of the cathode and the cathode, and tetrahydrofuran (THF) in which PhMgCl is dissolved at a concentration of 0.5 M is provided as an electrolyte. The coulombic efficiency (%) at the 20th cycle for testing the voltage range and charge and discharge cycles at 0.2C.

The coin cells in relations 1, 2 and 3 are half cells, and the negative electrode of the coin cell may be a negative electrode containing 80 wt% of a negative electrode active material, 10 wt% of a binder, and 10 wt% of carbon black (Super P).

The positive electrode active material of the positive electrode may be used as long as it is a material capable of reversible insertion and desorption of magnesium ions, and specifically, may be a transition metal compound capable of reversible insertion and desorption of magnesium ions. Specifically, the cathode active material is scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) And oxides, halides, chalcogenides, cyanides or mixtures thereof of at least one transition metal selected from zinc (Zn), molybdenum (Mo), niobium (Nb) and ruthenium (Ru). For example, Co ₃ O 4, Mn ₂ O ₃ , Mn ₃ O ₄ , MoO ₃ , PbO ₂ , Pb ₃ O ₄ , RuO ₂ , V ₂ O ₅ , WO ₃ , TiS ₂ , VS ₂ , ZrS ₂ , Mo ₃ O ₄ , Mo ₆ S ₈ , MoB ₂ , TiB ₂ , or a mixture thereof, and the like, but is not limited thereto.

The negative electrode may include a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer may include the above-described negative electrode active material, a binder, and a conductive material.

The positive electrode may also include a positive electrode active material layer containing a positive electrode active material and a positive electrode current collector, and the positive electrode active material layer may include a positive electrode active material, a binder, and a conductive material.

The binder of the negative electrode or the positive electrode may be a polymer commonly used to improve the binding force of the active material layer in the secondary battery field. That is, the polymer can be used as long as it does not chemically react with the electrolyte and can bind between the active material, the active material and the conductive material, the active material and the current collector, and the conductive material and the current collector. As a specific example, the binder of the negative electrode or the positive electrode, independently of each other, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trichloroethylene copolymer, polymethyl methacrylate , Polytetrafluoroethylene, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan , Cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, polyimide, polytetrafluoroethylene Or these Mixtures, and the like, but are not limited thereto.

The conductive material of the negative electrode or the positive electrode may be a conductive material that is commonly used to improve the electrical conductivity of the active material layer in the secondary battery field. Specifically, the conductive material of the negative electrode or the positive electrode, independently of each other, conductive carbon bodies such as carbon black, acetylene black, Ketjen black, channel black, Farnes black, lamp black, thermal black or a mixture thereof; Conductive fibers such as carbon fibers and metal fibers; Conductive nanostructures such as carbon nanotubes, carbon fibers, graphene, graphite (graphite), hard carbon, soft carbon, etc. may be, but are not limited thereto.

 The content of the conductive material and the binder contained in the negative electrode active material layer or the positive electrode active material layer may be stable electrical conduction and stable binding between components. For example, the negative electrode active material layer or the positive electrode active material layer may independently contain 5 to 50 parts by weight of a conductive material and 1 to 20 parts by weight of a binder based on 100 parts by weight of an active material (negative electrode active material or positive electrode active material), but is not limited thereto. It doesn't happen.

The current collector of the negative electrode or the positive electrode may have a good conductivity and may be a chemically stable material during charge and discharge of the battery. Specifically, the current collector of the negative electrode or the positive electrode may be independently a conductive material such as graphite, graphene, activated carbon, titanium, copper, platinum, aluminum, nickel, silver, gold, or carbon nanotubes. The current collector of the negative electrode or the positive electrode may be in the form of a foam, film, mesh, felt or porous film of a conductive material independently of each other. However, it is a matter of course that the present invention cannot be limited by the shape and the material of the current collector.

The negative electrode may be prepared by applying and drying a slurry containing a negative electrode active material, a conductive material, and a binder on a current collector, and optionally rolling may be further performed after drying is performed. Alternatively, the negative electrode may be a compressed body obtained by compressing a mixture containing a negative electrode active material, a conductive material, and a binder.

The positive electrode may also be prepared by applying and drying a slurry containing a positive electrode active material, a conductive material and a binder on a current collector, or by pressing a mixture containing the positive electrode active material, a conductive material and a binder. In the case of preparing the positive electrode by applying the slurry on the current collector, the rolling may be further performed after the drying is performed.

The electrolyte is a liquid containing magnesium ions, so long as it is an electrolyte solution commonly used in magnesium secondary batteries. The electrolyte may be a non-aqueous organic electrolyte or an aqueous electrolyte. The electrolyte solution may include a magnesium salt and a solvent to be an electrolyte. In the case of an aqueous electrolyte solution, the electrolyte may be a water-soluble magnesium salt such as Mg (OH) ₂ , MgSO ₄ , MgCl ₂ , Mg (NO ₃ ) _2, or the like. In the case of the aqueous electrolyte solution, the electrolyte concentration may be a saturation concentration or a concentration close to the saturation concentration. When the electrolyte is a non-aqueous electrolyte, the electrolyte may be a Grignard reagent-based electrolyte. Specifically, in the case of the non-aqueous electrolyte, the magnesium salt usable as the electrolyte is RMgX (R is a linear or branched alkyl group having 1 to 10 carbon atoms, a straight or branched aryl group having 1 to 10 carbon atoms, or 1 carbon atom). Straight or branched amine groups of 10 to 10, preferably methyl, ethyl, butyl, phenyl, or aniline groups, X is halogen and preferably chlorine or bromine), MgX ₂ (X is halogen) Preferably chlorine or bromine), R ₂ Mg (R is an alkyl group, a dialkyl boron group, a diaryl boron group, an alkylcarbonyl group (eg methylcarbonyl group (-CO ₂ CH ₃ )), an alkylsulfonyl group (e.g. For example, one or two or more selected from trifluoromethylsulfonyl group (-SO ₂ CF ₃ )), etc. may be selected, but is not limited thereto.The electrolyte may further include an additive such as AlCl ₃ , but is not limited thereto. Non-aqueous electrolysis Solvents are dimethyl ether, diethyl ether, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, methyl acetate, ethyl acetate, n Propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone, dibutyl Ether, tetraglyme, triglyme, diglyme, polyethyleneglycol dimethylether, dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, 2,5-dimethyltetrahydrofuran Cyclohexanone, triethylamine, triphenylamine, triether phosphine oxide, One or two or more may be selected from cetonitrile, dimethylformamide, 1,3-dioxolane, sulfolane, etc. One example of other non-aqueous electrolytes is non-aqueous as described above. Mg (TFSI) ₂ (magnesium bis (trifluoromethanesulfonyl) imide), Mg (FSI) ₂ (magnesium bis (fluorosulfonyl) imide), Mg (PF ₆ ) ₂ , Mg (ClO ₄ ) ₂ , Mg (HMDS) ₂ (magnesium hexamethyldisilazide), Mg (CB ₁₁ H ₁₂ ) ₂ (Magesium monocarborane) And MgCl ₂ An electrolyte containing one or two or more selected magnesium salts, but is not limited thereto.

The driving temperature of the magnesium secondary battery changes from room temperature to high temperature according to the composition of the electrolyte solution. Magnesium secondary battery of the present invention can be driven at room temperature (10 to 35 ℃), the driving temperature is not limited.

Magnesium secondary battery according to an embodiment of the present invention may further include a separator, the separator is located between the negative electrode and the positive electrode to facilitate the material movement including the magnesium ions while the electrical short circuit between the negative electrode and the positive electrode Can play a role of blocking. As the separator, conventional inorganic separators or organic separators conventionally used as separators may be used. A glass filter etc. are mentioned as an inorganic separator, A porous polymer film etc. are mentioned as an organic separator. Examples of the porous polymer film include porous polymer films made of polyolefin-based polymers such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, and the like. .

Magnesium secondary battery according to an embodiment of the present invention may have a structure commonly used in the secondary battery field, and may be a cylindrical, square, pouch (type) or coin (coin) using a can, but is not limited thereto. It doesn't happen.

(Example 1)

Preparation of Mg ₂ Sn Alloy

Mg metal powder (Aldrich) was mixed with 0.243g and Sn metal powder (Aldrich) 0.594g and perform a ball mill for 12 hours to 50 oscillation using zirconia balls were prepared Mg ₂ Sn alloy, it is manufactured of Mg ₂ Sn alloy The average particle diameter was 9 μm.

1 is an X-ray diffraction pattern of the prepared Mg ₂ Sn alloy, a crystalline Mg ₂ Sn intermetallic compound was prepared as shown in Figure 1, other secondary phase, unreacted residue or impurities It was confirmed that a crystalline Mg ₂ Sn single phase was produced without.

A negative electrode was prepared by mixing and pressing 80 wt% of a prepared Mg ₂ Sn alloy active material, 10 wt% of PTFE (polytetrafluoroethylene) as a binder, and 10 wt% of carbon black (Super P) as a conductive material.

PhMgCl (Ph = phenyl) was dissolved in tetrahydrofuran (THF) at a concentration of 0.5 M to prepare an electrolyte solution.

Subsequently, a coin cell type half-cell of 2016 was manufactured using the prepared negative electrode and the electrolyte as a counter electrode of magnesium metal foil.

The charge and discharge cycle test was performed at 0.2C in the voltage range of 0.05-0.6V, and the initial discharge was performed as the coin cell type half cell in the state immediately after the manufacture was in the charged state.

2 is a view showing the discharge capacity (mAh / g) and the coulomb efficiency (%) according to the number of charge-discharge cycles of the manufactured coin cell-type magnesium half-cell, blue circle is the discharge capacity, red square is the coulomb efficiency Means.

As shown in FIG. 2, the Mg ₂ Sn alloy negative active material shows an activity in the electrochemical reaction with magnesium ions in the magnesium cell and is reversibly charged and discharged. It can be seen that even if 20 cycles are performed, there is almost no deterioration of the battery and a stable charge / discharge cycle is achieved. The battery has a capacity of about 320 mAh / g for 20 cycles, and the initial coulombic efficiency is 86% and after the second cycle. It can be seen that the cycle efficiency is superior to 99% or more.

(Example 2)

In the same manner as in Example 1, after the Mg ₂ Sn cathode was manufactured, a coin cell-type complete product was prepared using a V ₂ O ₅ anode as a counter electrode and a diglyme in which Mg (TFSI) ₂ was dissolved at a concentration of 0.5 M as an electrolyte. Full-cell Mg ₂ Sn / V ₂ O ₅ was prepared.

The charge and discharge cycle test was performed at 25 ° C. at 0.05 C in the voltage range of 0.01-2.0 V, and the first discharge of the coin cell-type complete cell was performed as Mg ₂ Sn in the state of charge immediately after the manufacture was charged.

3 is a charge / discharge curve diagram showing the capacity (mAh / g) according to charge / discharge of the manufactured coin-cell type magnesium ion-complete Mg ₂ Sn / V ₂ O ₅ .

As shown in FIG. 3, the Mg ₂ Sn alloy negative active material is active in an electrochemical reaction with magnesium ions even in a magnesium ion cell composed of a V ₂ O ₅ positive electrode, and has an initial coulombic efficiency of 90% for three cycles. It can be seen that it is reversibly charged and discharged with a capacity of 149-102 mAh / g.

In the present invention as described above has been described by specific embodiments and limited embodiments and drawings, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, the present invention Those skilled in the art can make various modifications and variations from this description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

Claims (10)

1. In the as-synthesized state in which no charge / discharge is performed,

   A cathode comprising a transition metal compound capable of reversible insertion and detachment of magnesium ions as a cathode active material,

   A negative electrode including an Mg-Sn alloy as a negative electrode active material;

   Magnesium secondary battery containing an electrolyte solution.
2. The method of claim 1,

   The magnesium secondary battery is a magnesium secondary battery operated at room temperature.
3. The method of claim 1,

   The cathode active material is a magnesium secondary battery that does not contain magnesium.
4. The method of claim 2,

   The cathode active material is scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc Magnesium secondary battery which is an oxide, halide, chalcogenide, and cyanide of a transition metal selected from (Zn), molybdenum (Mo), niobium (Nb), and ruthenium (Ru).
5. The method of claim 2,

   The magnesium secondary battery is a magnesium secondary battery in a charged state.
6. The method of claim 1,

   The anode active material is Mg ₂ Sn magnesium secondary battery.
7. The method of claim 5,

   The anode active material is a magnesium secondary battery consisting of Mg ₂ Sn particles.
8. The method of claim 5,

   The magnesium secondary battery having an average diameter of the Mg ₂ Sn particles is 5nm to 20μm.
9. The method of claim 1,

   The electrolyte is a magnesium secondary battery that is a non-aqueous electrolyte containing magnesium ions.
10. The method of claim 1,

    The magnesium secondary battery further comprises a separator.

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