Magnesium secondary battery and method for manufacturing magnesium secondary battery

Abstract

To provide a magnesium secondary battery in which generation of internal short-circuits can be suppressed while reducing over-voltage, and a method for manufacturing the magnesium secondary battery.SOLUTION: The magnesium secondary battery according to the present invention includes: a positive electrode; a negative electrode with a magnesium layer made of a magnesium metal material; a separator; and an electrolyte. The peak intensity ratio, represented by (002) / (110), is within the range of 7 to 12, from the diffraction peak showing a (002) plane in the range of 2θ=35°±5° and the diffraction peak showing a (110) plane in the range of 2θ=57°±5° in a powder X-ray diffraction measurement using CuKα radiation of the negative electrode. The separator has a porosity W (%) of 40≤W≤50 and a film thickness X (μm) of 20≤X≤40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnesium secondary battery and a method for manufacturing a magnesium secondary battery. [Background technology]

[0002] In recent years, environmental issues have become serious problems. Therefore, natural energy power generation is desired from the viewpoint of environmental burden. However, natural energy has an unstable energy supply, and once generated, electrical energy needs to be stored. Therefore, there is a demand for high-capacity power storage devices that can store such large amounts of electrical energy.

[0003] Currently, lithium ion secondary batteries and magnesium secondary batteries are known as power storage devices. Among them, magnesium secondary batteries have attracted attention as batteries that are expected to have high energy density because the carrier is a divalent magnesium ion (see, for example, Patent Document 1). In addition, magnesium metal is more stable in air than lithium metal and has about 1.5 times the theoretical capacity per volume, so there is a demand for practical use of magnesium metal as a metal secondary battery in the negative electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 013328 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there are many difficulties in putting magnesium secondary batteries to practical use, and the large overvoltage is one of the hurdles to practical use.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnesium secondary battery with reduced overvoltage and a method for manufacturing the magnesium secondary battery. [Means for solving the problem]

[0007] In order to solve the above problems, the magnesium secondary battery of the present invention comprises a positive electrode, a negative electrode having a magnesium layer made of a magnesium alloy or pure magnesium, a separator, and an electrolyte, and is characterized in that in powder X-ray diffraction measurement of the negative electrode using CuKα radiation, the peak intensity ratio Y represented by (002) / (110) is 7 or more and 12 or less, based on the diffraction peak representing the (002) plane within the range of 2θ=35°±5° and the diffraction peak representing the (110) plane within the range of 2θ=57°±5°, and the separator has a porosity W (%) of 40≦W≦50 and a film thickness X (μm) of 20≦X≦40. The peak intensity ratio is sometimes referred to as "diffraction peak intensity ratio".

[0008] By using the above-mentioned magnesium secondary battery, it is possible to provide a magnesium secondary battery capable of reducing overvoltage.

[0009] In addition to the first aspect, the magnesium secondary battery according to the present invention is characterized in that, as a second aspect, the magnesium alloy contains aluminum and zinc.

[0010] In addition to the first or second aspect, the magnesium secondary battery according to the present invention is characterized as a third aspect in that it is a battery that starts with charging.

[0011] In addition, as a fourth aspect, the present invention provides a method for producing a magnesium secondary battery comprising a positive electrode, a negative electrode having a magnesium layer made of a magnesium alloy or pure magnesium, a separator, and an electrolyte, the method comprising the steps of: 2 The above-mentioned charging and discharging steps are performed as an activation step.

[0012] In addition, the method for manufacturing a magnesium secondary battery according to the present invention, as a fifth aspect in addition to the fourth aspect, is characterized by performing 10 or more cycles of one charge-discharge cycle in which charging and discharging are each performed for 1 hour or more.

[0013] In addition, the method for manufacturing a magnesium secondary battery according to the present invention, as a sixth aspect in addition to the fourth or fifth aspect, is characterized by including one charge-discharge cycle in which the upper limit of SOC during charging is performed at 10% or more and 50% or less.

[0014] In addition, the method for manufacturing a magnesium secondary battery according to the present invention, as a seventh aspect in addition to any one of the fifth to sixth aspects, is characterized by using a negative electrode having a magnesium layer made of a magnesium alloy containing 3% or more of another metal by weight.

[0015] In addition, the method for manufacturing a magnesium secondary battery according to the present invention, as an eighth aspect in addition to any one of the fifth to seventh aspects, is characterized by using a substance containing a magnesium element for the positive electrode.

Advantages of the Invention

[0016] According to the present invention, in a magnesium secondary battery, it is possible to suppress the occurrence of internal short circuits while reducing overvoltage.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is an exploded perspective view for explaining the configuration of a magnesium secondary battery according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, a first embodiment of the present invention will be described, but the present invention is not limited to the following description. In addition, various changes or improvements can be made to this embodiment, and forms with such changes or improvements can also be included in the present invention.

[0019] The magnesium secondary battery according to the present invention includes a positive electrode, a separator, a negative electrode, an electrolytic solution, and an exterior body that houses them. The positive electrode and the negative electrode are arranged such that their active materials face each other, and a separator is present between the positive electrode and the negative electrode.

[0020] (Embodiment) FIG. 1 is an exploded perspective view for explaining the configuration of a magnesium secondary battery according to an embodiment of the present invention. The magnesium secondary battery 1 includes a case 110, a leaf spring 111, a positive electrode current collector 112, a positive electrode composite material layer 113, a separator 114, a negative electrode 115, a gasket 116, and a cap 117. Note that the positive electrode 118 is constituted by the positive electrode current collector 112 and the positive electrode composite material layer 113. Further, not limited to this form, a form including a plurality of positive electrodes and negative electrodes is also preferably used, and it can also be used as a magnesium secondary battery using a laminated pouch.

[0021] In the magnesium secondary battery 1, the case 110 and the cap 117 are fixed by caulking or the like, and the inside is filled with a non-aqueous electrolytic solution. In the magnesium secondary battery 1, it is hermetically sealed by the case 110, the gasket 116, and the cap 117. Further, the positive electrode current collector 112, the positive electrode composite material layer 113, the separator 114, and the negative electrode 115 are biased toward the cap 117 side by the leaf spring 111. Thereby, a state in which each member is in close contact with each other is maintained.

[0022] (Positive Electrode) According to an embodiment of the present invention, there is provided a positive electrode for a magnesium secondary battery (positive electrode 118) including at least a positive electrode current collector and a positive electrode composite material layer provided on one or both sides of the positive electrode current collector.

[0023] There is no particular limitation on the material constituting the positive electrode current collector 112, but it is preferable to use a metal. Specifically, copper, aluminum, nickel, stainless steel, titanium, other alloys, etc. can be mentioned. Among them, aluminum is preferable from the viewpoints of electron conductivity and battery operating potential.

[0024] Examples of the binder used in the positive electrode composite layer 113 include polyethylene, polypropylene, ethylene propylene terpolymer, butadiene rubber, styrene butadiene rubber, butyl rubber, polytetrafluoroethylene, poly(meth)acrylate, polyvinylidene fluoride, polyethylene oxide, polypropylene oxide, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, and the like, or a mixture thereof.

[0025] The positive electrode active material is MgCo 2 O 4 , MgFeSiO 4 , S, MnO 2 , Mo 6 S 8 , V 2 O 5 In order to improve electronic conductivity, the material may contain conductive carbon powder such as graphite or carbon black, carbon nanotubes, carbon nanofibers, graphene, or a mixture thereof. The material containing magnesium element is, for example, MgCo 2 O 4 , MgFeSiO 4 and other materials are, for example, MnO 2 , Mo 6 S 8 , V 2 O 5 As described below, materials containing magnesium element are usually the main component of the positive electrode of a battery that starts with charging.

[0026] (Negative electrode) According to one embodiment of the present invention, there is provided a negative electrode (negative electrode 115) for a magnesium secondary battery, which comprises at least a negative electrode current collector and a magnesium layer made of a magnesium metal material provided on one or both sides of the negative electrode current collector. Also, the negative electrode current collector may not be used.

[0027] There is no particular limitation on the material constituting the negative electrode current collector, but it is preferable to use a metal. Specific examples include copper, aluminum, nickel, stainless steel, titanium, and other alloys. Among them, copper is preferable from the viewpoint of electronic conductivity and battery operating potential.

[0028] The magnesium metal material is a magnesium metal alloy or pure magnesium. In particular, it is preferably a magnesium alloy containing 3% or more by weight of other metals. This is because it is more susceptible to the effect of the method for controlling the electrode surface state described later than pure magnesium. Furthermore, it is preferable that the crystal structure is a hexagonal close-packed (hcp) structure. More preferably, the magnesium metal material is a magnesium metal alloy containing aluminum and zinc. It may also contain copper. The reason why it is preferable to use a magnesium metal alloy negative electrode containing aluminum and zinc is that it is stable in the air and has excellent handling properties.

[0029] The magnesium metal material has a diffraction peak representing the (002) plane within the range of 2θ=35°±5° and a diffraction peak representing the (110) plane within the range of 2θ=57°±5°, and the peak intensity ratio Y represented by (002) / (110) is 7 or more and 12 or less. If a negative electrode other than that of the present invention is used, it may be difficult to insert and remove magnesium ions into and from the bulk, and good charge and discharge characteristics may not be obtained.

[0030] In this embodiment, the magnesium metal material is characterized in that, in powder X-ray diffraction measurement, the peak intensity ratio Y represented by (002) / (110) is 7 or more and 12 or less (7≦Y≦12) based on the diffraction peak representing the (002) plane within the range of 2θ=35°±5° and the diffraction peak representing the (110) plane within the range of 2θ=57°±5°. The reason why it is preferable to use the negative electrode according to this embodiment is that it enables the suppression of overvoltage. This is a problem that occurs because the magnitude of overvoltage changes depending on which plane the electrochemical activity depends on on the electrode surface even in magnesium alloys or pure magnesium. To solve this problem, a magnesium metal alloy negative electrode is used in which the peak intensity ratio Y of the (002) / (110) plane is 12≧Y in X-ray diffraction measurement. The (001) and (002) plane orientations, which are the bottom surfaces of magnesium, are electrochemically inactive planes. On the other hand, the (101) and (110) plane orientations originating from the side surface are electrochemically active planes. It is known that the (110) plane is more electrochemically active than the (001) plane (see, for example, C. Ling et al., Electrochmica Acta 76 (2012), 270-274). Along with the (001) plane, the (002) plane, which represents the orientation of the basal surface of magnesium, is also less active than the (110) plane. Therefore, when a magnesium metal alloy negative electrode in which the peak intensity ratio Y of the (002) / (110) plane is 12≧Y is used, a state in which many active surfaces exist on the electrode surface is achieved. If a magnesium metal alloy negative electrode having a peak intensity ratio Y of Y<7 is used, the overvoltage may become too large during the activation step, making activation impossible.

[0031] In addition, by using a magnesium metal alloy with a surface state where the peak intensity ratio Y of the (002) / (110) plane is 12 or more, the electrode surface has many active surfaces, which allows the magnesium ions to move more smoothly. As a result, it is possible to reduce the overvoltage during dissolution and deposition of magnesium.

[0032] Regular magnesium metal negative electrodes, including newly completed magnesium metal alloy or pure magnesium negative electrodes, do not satisfy the condition that the peak intensity ratio Y of the (002) / (110) plane is 7 to 12. Therefore, in order to control the electrode surface state like the above magnesium metal alloy negative electrode, an activation process was performed on the magnesium metal alloy or pure magnesium negative electrode. At this time, a low current density, for example 5 mA / cm 2 When constant-current charging and discharging is performed at less than 1000 mA, the magnesium deposited will be particles with a large proportion of the bottom surface ((002) plane), which is a thermodynamically stable crystal face. On the other hand, when constant-current charging and discharging is performed at a high current density, particles with a large proportion of the thermodynamically unstable side surface ((110) plane) will be deposited. In other words, by performing a manufacturing method that includes an activation step in which the current density is controlled, it is possible to produce a magnesium metal alloy negative electrode in which the peak intensity ratio Y of the (002) / (110) plane is 12 ≧ Y.

[0033] The peak intensity ratio Y of the (002) / (110) plane can be adjusted, for example, by the current density during the activation step. 2 If the current density is set to 5 mA / cm or higher (hereinafter sometimes referred to as high current density), the electrochemically active side surfaces ((110) and (100)) will be more oriented on the surface of the electrodeposited magnesium, and the intensity ratio Y will also be large. However, if the current density is set too high, the overvoltage will increase and constant current charging and discharging will become impossible. Therefore, it is recommended to set the current density to 5 mA / cm or higher. 2 More than 25mA / cm 2 It is preferable that the current is less than 5 mA / cm 2 More than 15mA / cm 2 It is more preferable to set it as follows:

[0034] Here, in the negative electrode of the present invention, even if the magnesium alloy or pure magnesium of the negative electrode is not dissolved during the first discharge, it is possible to suppress overvoltage and internal short circuit. This is because the formation of a passive film (oxide film) on the surface of the negative electrode is prevented. This makes it suitable for a type of battery that requires charging immediately after assembling the cell, such as one that contains magnesium element in the positive electrode (sometimes referred to as a "battery that starts with charging" in this specification). Whether or not the battery starts with charging can be confirmed even after the activation process by checking whether the magnesium ion starts with insertion or removal from the positive electrode from the internal components scraped off the surfaces of the positive and negative electrodes, and a person skilled in the art can easily determine whether or not the battery starts with charging.

[0035] In addition, except for special alloys, the crystal structure of magnesium alloys is the hcp structure.

[0036] (electrolyte) The magnesium salt contained in the non-aqueous electrolyte is MgCl 2 , MgBH 4 , Mg(NO 3 ) 2 , Mg(TFSI) 2 , Mg(SO 2 CF 3 ) 2 , Mg(BF 4 ) 2 , Mg(CF 3 SO 3 ) 2 , Mg(PF 6 ) 2 Examples of the suitable amines include, but are not limited to, one or a mixture of two or more selected from the following:

[0037] The non-aqueous solvent contained in the non-aqueous electrolyte is not particularly limited, and examples thereof include one or a mixed solvent of two or more selected from dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), methyl propionate, methyl acetate, methyl formate, methyl butyrate, dioxolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethoxyethane, γ-butyrolactone, acetonitrile, benzonitrile, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraglyme dimethyl ether (tetraglyme), sulfolane, and the like.

[0038] (Separator) Examples of the separator include a porous sheet separator made of polymer or fiber, and a nonwoven fabric separator. The separator has a porosity W (%) of 40≦W≦50 and a thickness X (μm) of 20≦X≦40. Since the electrode surface is the active surface, sufficient effects can be obtained even if the separator does not have a porosity of more than 50, which is preferred for magnesium secondary batteries. In addition, if the thickness is within the above range, the electrode is the active surface, so that the electrolytically deposited magnesium becomes small particles and does not deposit on multiple surfaces, causing a short circuit. The use of a separator within the above range not only suppresses the formation of a passive film on the negative electrode surface due to the peak intensity ratio of the present invention, but also suppresses the coarsening of the deposited magnesium, which is expected to be effective in suppressing overvoltage and internal short circuit. These effects make the separator even more suitable for batteries that start charging.

[0039] In this embodiment, the magnesium secondary battery 1 is prepared by arranging the leaf spring 111, the positive electrode current collector 112, the positive electrode composite layer 113, the separator 114, the negative electrode 115, and the gasket 116 in this order, sandwiching them between the case 110 and the cap 117, filling them with a non-aqueous electrolyte, and then fixing the case 110 and the cap 117 by caulking or the like to provide a liquid-tight seal, after which an activation process is carried out. In this activation process, a current of 5 mA / cm 2 It is preferable to perform 10 or more cycles of charging for 1 hour or more and discharging for 1 hour or more at a current density of 10% or more. In addition, it is preferable to perform the activation process while keeping the SOC (State of Charge) of the battery between 10% and 50% as the upper limit of the voltage during charging. The maximum state of charge of 10% to 50% may be achieved in one cycle, but it is more preferable to achieve this in all cycles. This ensures that a negative electrode with the above-mentioned peak intensity ratio Y≦12 can be obtained. EXAMPLES

[0040] The present invention will be described in more detail below by way of examples, but the present invention is not limited to the following embodiments.

[0041] (Level 1) <Constant current test> In level 1, the electrodes are made of a magnesium alloy containing 3% by weight of aluminum and 1% by weight of zinc, the separator is a polyethylene separator with a porosity of 47% and a thickness of 25 μm, and the electrolyte is Mg(TSFA). 2 LiBH to / G2(Diethyleneglycol dimethyl ether) 4 A constant current test was carried out on a symmetrical cell with a laminate exterior using an electrolyte containing an additive of 1 mA / cm. The measurement conditions were: 2 The battery was charged for one hour and discharged for one hour for 100 cycles at room temperature (25°C). <Activation process> Before performing the constant current test, the above cell was charged at 5 mA / cm as an activation step. 2An activation process was performed in which one cycle of charging for 1 hour and discharging for 1 hour was repeated 10 times. The test results at level 1 are shown in Table 1.

Table 1

[0042] (Level 2) The battery configuration is the same as that at level 1. The test method was the same as that at level 1, except for the activation process. Also, before performing the constant current test, as an activation process, charging was performed at 10 mA / cm2 for 1 hour and discharging was performed for 1 hour, and a 10-cycle activation process was carried out. The test results at level 2 are shown in Table 1.

[0043] (Level 3) The battery configuration is the same as that at level 1. The test method was the same as that at level 1, except for the activation process. Also, before performing the constant current test, as an activation process, charging was performed at 5 mA / cm 2 for 0.5 hour and discharging was performed for 0.5 hour, and a 10-cycle activation process was carried out. The test results at level 3 are shown in Table 1.

[0044] (Level 4) The battery configuration is the same as that at level 1. The test method was the same as that at level 1, except for the activation process. Also, before performing the constant current test, as an activation process, charging was performed at 4 mA / cm 2 for 1 hour and discharging was performed for 1 hour, and a 10-cycle activation process was carried out. The test results at level 4 are shown in Table 1.

[0045] (Level 5) The battery configuration is the same as that at level 1. The test method was the same as that at level 1, except for the activation process. Also, before performing the constant current test, as an activation process, charging was performed at 1 mA / cm 2 for 1 hour and discharging was performed for 1 hour, and a 10-cycle activation process was carried out. The test results at level 5 are shown in Table 1.

[0046] (Level 6) The battery structure is the same as that of Level 1. The test method was performed under the same conditions as Level 1, except for the activation process. In addition, before the constant current test, a 5 mA / cm 2 The battery was charged at 1000 V for 0.4 hours and discharged at 1000 V for 0.4 hours, and the activation process was carried out for 10 cycles. The test results for level 6 are shown in Table 1.

[0047] (Level 7) The battery structure is the same as that of Level 1. The test method was performed under the same conditions as Level 1, except for the activation process. In addition, before the constant current test, a 5 mA / cm 2 The battery was charged for 2.5 hours and discharged for 2.5 hours at 1000 kPa (1000 psi) for 10 cycles. The test results for level 7 are shown in Table 1.

[0048] (Level 8) The battery structure is the same as in Level 1. The test method was performed under the same conditions as Level 1, except for the activation process. In addition, before the constant current test, a 25 mA / cm 2 We attempted to perform a 10-cycle activation process by charging at 1000V for 1 hour and discharging at 1000V for 1 hour, but the experiment was interrupted midway because the SOC exceeded 100%. The test results for level 8 are shown in Table 1.

[0049] (Level 9) The battery structure is the same as that of Level 1. The test method was the same as that of Level 1, except for the activation process. In addition, the activation process was not performed. The test results for Level 9 are shown in Table 1.

[0050] (Level 10) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 30% and a thickness of 30 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 10 are shown in Table 1.

[0051] (Level 11) The battery structure is the same as that of Level 1, except for the separator. The separator used was a polyethylene separator with a porosity of 70% and a thickness of 40 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 11 are shown in Table 1.

[0052] (Level 12) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 47% and a thickness of 10 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 12 are shown in Table 1.

[0053] (Level 13) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 47% and a thickness of 50 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 13 are shown in Table 1.

[0054] (Level 14) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 47% and a thickness of 20 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 14 are shown in Table 1.

[0055] (Level 15) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 47% and a thickness of 40 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 15 are shown in Table 1.

[0056] (Level 16) The battery structure is the same as that of Level 1, except for the separator. The separator used is a polyethylene separator with a porosity of 40% and a thickness of 25 μm. The test method, including the activation process, was performed under the same conditions as Level 1. The test results for Level 16 are shown in Table 1.

[0057] (Level 17) The battery configuration is the same as that of Level 1 except for the separator. A polyethylene separator with a porosity of 50% and a thickness of 25 μm was used as the separator. The test method was the same as that of Level 1 under the same conditions including the activation process. The test results at Level 17 are shown in Table 1.

[0058] (Level 18) The battery configuration is the same as that of Level 1 except for the separator. A polyethylene separator with a porosity of 30% and a thickness of 10 μm was used as the separator. The test method was the same as that of Level 1 under the same conditions including the activation process. The test results at Level 18 are shown in Table 1.

[0059] (Level 19) The battery configuration is the same as that of Level 1 except for the separator. A polyethylene separator with a porosity of 70% and a thickness of 50 μm was used as the separator. The test method was the same as that of Level 1 under the same conditions including the activation process. The test results at Level 19 are shown in Table 1.

[0060] From Table 1, at Levels 1 to 3 where the (002) / (110) peak intensity ratio Y is 7 or more and 12 or less, the overvoltage after 100 cycles is as good as 0.22 V or less, and good values were obtained without internal short circuit. Also, at 5 mA / cm 2In levels 1 to 3 and 6, which include an activation step in which charging is performed at or above 100 μm, the overvoltage after one cycle was good at 0.31 V or less, and good values ​​were obtained without any internal short circuit. On the other hand, in levels 4 and 5, in which the (002) / (110) peak intensity ratio Y is greater than 12, and in level 9, in which the activation step is not performed, the overvoltage after 100 cycles was 0.427 V or more, which is an unfavorable result. In level 7, in which Y is less than 7, an internal short circuit occurred, and in level 8, in which the activation current value is high, the activation step itself was impossible. From the viewpoint of the separator, levels 11 and 12, in which the porosity is greater than 50 or the thickness is less than 20 μm, an internal short circuit occurred, and in levels 10 and 13, in which the porosity is less than 40 or the thickness is greater than 40 μm, an overvoltage after 100 cycles was 0.44 V or more, which is an unfavorable result. Levels 18 and 19, in which both the porosity and thickness are inappropriate, also showed unfavorable results with internal short circuits. In contrast, in the cases of levels 14 to 17 where the porosity was 40 or more and 50 or less and the thickness was 20 or more and 40 μm or less, the overvoltage after 100 cycles was 0.27 or less, which was a favorable result. From the above results, it is possible to provide a magnesium secondary battery capable of reducing overvoltage by controlling the surface state of the electrochemically active electrode in the negative electrode. [Explanation of symbols]

[0061] 1. Magnesium secondary battery 110 cases 111 Leaf spring 112 Positive electrode current collector 113 Positive electrode composite layer 114 Separator 115 Negative electrode 116 Gasket 117 Cap 118 Positive electrode

Claims

1. A positive electrode and a negative electrode having a magnesium layer made of a magnesium alloy or pure magnesium; A separator; An electrolyte; Equipped with In a powder X-ray diffraction measurement of the negative electrode using CuKα rays, a peak intensity ratio represented by (002) / (110) is 7 or more and 12 or less, based on a diffraction peak representing a (002) plane within a range of 2θ=35°±5° and a diffraction peak representing a (110) plane within a range of 2θ=57°±5°, and the separator has a porosity W (%) of 40≦W≦50 and a film thickness X (μm) of 20≦X≦40. A magnesium secondary battery comprising:

2. The magnesium alloy includes aluminum and zinc.

2. The magnesium secondary battery according to claim 1 .

3. This is a battery that starts by charging.

2. The magnesium secondary battery according to claim 1 .

4. A method for manufacturing a magnesium secondary battery including a positive electrode, a negative electrode having a magnesium layer made of a magnesium alloy, a separator, and an electrolyte, comprising: 5mA / cm ２ The activation step involves charging and discharging the material. A method for producing a magnesium secondary battery comprising the steps of:

5. 5. The method for producing a magnesium secondary battery according to claim 4, wherein one charge / discharge cycle, in which charging and discharging are each performed for one hour or more, is performed 10 or more times.

6. 5. The method for producing a magnesium secondary battery according to claim 4, further comprising one charge / discharge cycle in which the upper limit of SOC during charging is between 10% and 50%.

7. 5. The method for producing a magnesium secondary battery according to claim 4, wherein a negative electrode having a magnesium layer made of a magnesium alloy containing 3% by weight or more of other metals is used.

8. 5. The method for producing a magnesium secondary battery according to claim 4, wherein a substance containing magnesium element is used for the positive electrode.

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