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`
`Notice
`This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
`complete, reliable or fit for specific purposes. Critical decisions, such as com mercially relevant or
`financial decisions, should not be based on machine-translation output.
`
`DESCRIPTION JP2013073791A
`10 Non-aqueous electrolyte secondary battery
`
`[0001]
`14 The present invention relates to a non-aqueous electrolyte secondarybattery, and particularly
`to a novel positive electrode active material thereof.
`
`[0002]
`i9In recent years, secondary batteries have been developed as small secondary batteries, power
`sources for mobile devices, and stationary power sources, and there is an extremely high
`demand for higher energy density and higher performance of secondary batteries in various
`fields. .
`
`[0003]
`26 In particular, in order to use secondary batteries as power sources for movable bodies and
`stationary power sources, it is necessary to connect a large number of batteries in series or
`parallel to form modules, which increases the number of batteries. There is a need to develop
`secondary batteries with high energy density in order to minimize energy consumption,
`30 Non-aqueous electrolyte secondary batteries have a higher operating voltage than aqueous
`solution secondary batteries, and are preferable secondary batteries from the above point of
`view. The active material is in the 600 to 800 Wh/kg class, and even higher energy density is
`desired,
`
`[0004]
`37 From this point of view, several positive electrode active materials for non-aqueous electrolyte
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`secondary batteries have been proposed.
`39 For example, Patent Document 1 and Patent Document 2 disclose the use of halides with high
`electronegativity such as FeF3 and Li3FeF6, but because the redox potential of the metal
`element used is low, only a discharge voltage of about 3V can be obtained. . In addition, the
`above-mentioned active material can increase the charge/discharge capacity by utilizing a
`conversion reaction in which the alkali metal Li in the structure separates from the bond with
`the metal element Fe and combines with halogen, especially fluorine (F). However, the reaction
`in this conversion region is less reversible and the operating voltage is low. In order to achieve
`high energy density, it is desirable to use only the insertion reaction region where the change
`in host structure during charge/discharge reactions is small.
`
`[0005]
`51
`
`52
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`-
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`-
`
`[0006]
`56In view of the conventional problems, the present invention aims to provide a non-aqueous
`electrolyte secondary battery that uses a novel positive electrode active material, has high
`energy density, and has good reversibility.
`
`[0007]
`62 In order to solve these problems, the present invention provides a non-aqueous electrolyte
`secondary battery comprising a positive electrode and a negative electrode in which a lithium-
`containing compound is the main positive electrode active material, in which the lithium-
`containing compound has the following composition formula (2), It is intended to be a non-
`aqueous electrolyte secondary battery that satisfies the above requirements.
`
`[0008]
`70 A3M Xb (Ais Li, M is Mn, It is also preferable that the metal element be made of a substituted
`metal element,
`
`72 By substituting Mn (trivalent) in the composition with a metal element with a different ionic
`radius, volume fluctuations such as expansion and contraction of the crystal lattice and
`distortion that occur with charging and discharging are suppressed, and the crystal structure
`is stabilized. Improves durability.
`
`[0009]
`79 Further, the metal element is one or more elements selected from Ti, V, Cr, Ni, Fe, Co, Cu, Zn, Y,
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`Zr, Nb, Mo, W, Ca, Sr, Ba, Al, and Bi, It is preferable that
`81 These elements are 3d transition, 4d transition, and 4f transition elements, and have ionic radii
`close to Mn (trivalent).
`83 These elements are preferable because substitution is impossible if the ionic radii are too
`different,
`
`[0010]
`88 Furthermore, X in the compositional formula consists of F and O which further substituted a
`part of F, and bin the compositional formula is 6-x, provided that x satisfies 0
`x<0.05. is also
`preferable,
`91 Here, if it exceeds 0.05, the voltage may drop or the crystal structure may not be maintained.
`
`[0011]
`95 By substituting a part of It becomes possible to substitute other metal elements, causing
`crystal distortion and atomic defects, and facilitating the diffusion of ions in the solid phase,
`further improving battery characteristics,
`
`[0012]
`101 As explained above, according to the present invention, when A is an alkali metal whose main
`component is Li, M is a metal element whose main component is Mn, and X is a ligand whose
`main component is F, By using a lithium-containing compound whose compositional formula
`is A3MX6 and whose crystal structure belongs to C2/c as the main positive electrode active
`material, a non-aqueous electrolyte secondary battery with extremely high energy density
`can be provided.
`
`[0013]
`110 A longitudinal cross-sectional view of a non-aqueous electrolyte secondary battery according
`to an embodiment of the present invention
`
`[0014]
`115 The present invention will be explained in more detail below.
`116 That is, in order to provide a non-aqueous electrolyte secondary battery with good
`reversibility in the charge/discharge reaction and a high discharge voltage, firstly, a crystal
`structure having a diffusion path for Li tons to cause a highly efficient charge/discharge
`reaction is required. As a result of intensive research, we found that the alkali metal
`containing Li as the main component was found to be com posed of metal elements and
`ligands that can obtain high energy density as a positive electrode for non-aqueous
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`electrolyte secondary batteries, If Ais a metal element whose main component is Mn, and X
`is a ligand whose main component is F, then a compound having a composition represented
`by A3MX6 and a structure belonging to space group C2/c is The above-mentioned problems
`can be solved by using it as the main positive electrode active material, and when the above-
`mentioned ligand, especially fluorine, is used, the positive electrode active material can
`realize a high energy density of 1000 Wh/kg class. ] found out.
`
`[0015]
`131 The reason why the active material shown in the present invention has a high discharge
`voltage and exhibits good charge/discharge behavior is considered as follows.
`
`[0016]
`136 The voltage exhibited by an active material for a battery largely depends on the electronic
`state, that is, the electric charge, of a metal element that performs charge transfer in the
`active material, and therefore, the selection of the metal element is important,
`139 Com pounds of metal elements such as Co, Ni, Mn, V, and Fe are used as the positive electrode
`of non-aqueous electrolyte secondary batteries. A charge transfer reaction takes place
`between the transition metals, which exhibits a high potential among transition metal
`elements, and also produces compounds with relatively high chemical stability,
`143 Further, it has lower toxicity than compounds such as Cr and V, and is cheaper than Co.
`
`[0017]
`147 Among Mn compounds having such characteristics, in order to be usable as an active material
`for non-aqueous electrolyte secondary batteries, it is necessary to have a Li diffusion path in
`the crystal structure.
`150 The crystal structure of the compound showing the precursor composition A3 M X6 is
`monoclinic C2/c, and the alkali metal A and the metal element M, mainly Mn, share an 8f site
`surrounded by six ligands X and form a tunnel. forming a structure.
`153 Such a tunnel structure provides a good diffusion path for the alkali metal A.
`154 That is, it is considered that the alkali metal A diffuses while hopping at the &f site, thereby
`enabling a highly reversible charge/discharge reaction.
`
`[0018]
`159 On the other hand, as described above, the potential has a positive correlation with the charge
`of the metal element, so in order to achieve high energy density, the ligand should be
`selected so that the metal element has a high charge.
`162 In the active material, highly electronegative F, 0, etc. combine with the metal element as a
`ligand, thereby depriving the metal element of electrons, so that the effective charge of the
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`metal element becomes high, and therefore a high discharge voltage can be obtained. .
`165 In particular, when F, which has high electronegativity, is coordinated, the effect is
`significantly large and an active material with high energy density can be obtained, which is
`preferable.
`
`[0019]
`171 By replacing a very small number of the ligands It becomes possible to substitute other metal
`elements that can take several states, causing crystal distortion and atomic defects, and
`facilitating the diffusion of ions in the solid phase, further improving battery characteristics.
`174 However, since excessive substitution will actually lower the voltage, the amount of ligand
`substitution should be within the optimum range in order to solve the above problem.
`
`[0020]
`179 As described above, the configuration of the present invention makes it possible to provide a
`high energy density non-aqueous electrolyte secondary battery with good reversibility.
`
`[0021]
`184 Hereinafter, specific examples of the present invention will be explained.
`185 The non-aqueous electrolyte secondary battery of the present invention is characterized by
`the positive electrode active material, and other components are not particularly limited.
`
`[0022]
`190 FIG. 1 shows across section of a coin-type nonaqueous electrolyte secondary battery as an
`example of the present invention.
`192 In FIG. 1, 1 is a battery case made of a stainless steel plate resistant to organic electrolyte, 2 is
`a sealing plate made of the same material as the battery case 1, and 3 is a current collector
`made of the same material as the sealing plate 2,
`195 The current collector 3 is spot welded to the inner surface of the battery case l.
`1964 is a lithium metal negative electrode, and 5 is a positive electrode of the present invention,
`which is constructed using, for example, Li3 MnF6 as an active material, acetylene black as a
`conductive agent, and polytetrafluoroethylene as a binder.
`1996 ig a microporous polypropylene separator, and 7 is a polypropylene insulating gasket.
`
`[0023]
`203 (Example 1) The positive electrode active material was prepared by mixing com mercially
`available MnF2 and LiF at a molar ratio of 1:3.3 in an Ar atmosphere, kneading in a mortar,
`and then baking at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
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`[0024]
`209 Using the obtained Li3 MnF6, a positive electrode 5 of a non-aqueous electrolyte secondary
`battery was constructed as follows.
`211 Under an Ar atmosphere, Li3 MnF6, acetylene black, and polytetrafluoroethylene as a binder
`were mixed in a ratio of 80:10:10, kneaded in a mortar, and then pressure-molded to form a
`pellet shape with a thickness of 200 Um anda diameter of 12 mm. It was used as a drug.
`
`[0025]
`217 Using the positive electrode plate thus obtained, an evaluation battery was constructed as
`follows.
`
`219 For the lithium metal negative electrode 4, a piece of metal lithium foil (thickness 0.1 mm)
`punched out to a size of 15 mm was used.
`221 For the electrolyte, a mixture of ethylene carbonate and ethyl methyl carbonate at a ratio of
`1:3 was used as a solvent, and as an electrolyte supporting salt, an organic solvent electrolyte
`in which 1 mol of LiPF6 was dissolved per liter was used.
`224 As the separator 6, a porous membrane made of polypropylene with a thickness of 20 um
`was used,
`
`226 These positive electrode 5 and lithium metal negative electrode 4 were placed in a stainless
`steel battery container with a separator 6 in between, and after a non-aqueous solvent
`electrolyte was injected, the container was sealed with a lid through an insulating gasket 7.
`
`[0026]
`232 (Example 2) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Ti0.05F6 was used as the positive electrode active material.
`
`[0027]
`237 The positive electrode active material was prepared by mixing com mercially available MnF2,
`TiF2, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0028]
`243 (Example 3) A battery was used that was manufactured in the same manner as in Example 1,
`except that Li3Mn0.95V0.05F6 was used as the positive electrode active material.
`
`[0029]
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`248 The positive electrode active material was prepared by mixing com mercially available MnF2,
`VF2, and LiF in an Ar atmosphere at a molar ratio of 0.95:0.05:3.3, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0030]
`254 (Example 4) A battery was used which was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Cr0.05F6 was used as the positive electrode active material.
`
`[0031]
`259 The positive electrode active material was prepared by mixing com mercially available MnF2,
`CrF2, and LiF in a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then calcining it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0032]
`265 (Example 5) A battery was used which was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Ni0.05F6 was used as the positive electrode active material.
`
`[0033]
`270 The positive electrode active material was prepared by mixing com mercially available MnF2,
`NiF2, and LiF in a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading in a mortar,
`and then baking at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0034]
`276 (Example 6) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Fe0.05F6 was used as the positive electrode active material.
`
`[0035]
`281 The positive electrode active material was prepared by mixing com mercially available MnF2,
`FeF2, and LiF at a molar ratio of 0.95:0,05:3,3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0036]
`287 (Example 7) A battery was used which was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Co0.05F6 was used as the positive electrode active material.
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`[0037]
`292 The positive electrode active material was prepared by mixing com mercially available MnF2,
`CoF2, and LiF at a molar ratio of 0.95:0.05:3,3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0038]
`298 (Example 8) A battery was used which was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Cu0.05F6 was used as the positive electrode active material.
`
`[0039]
`303 The positive electrode active material was prepared by mixing com mercially available MnF2,
`CuF2, and LiF in a molar ratio of 0.95:0.05:3.3 in an Ar at mosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0040]
`309 (Example 9) A battery was used which was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Zn0.05F6 was used as the positive electrode active material.
`
`[0041]
`314 The positive electrode active material was prepared by mixing com mercially available MnF2,
`ZnF2, and LiF in a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 °C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0042]
`320 (Example 10) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Y0.05F6 was used as the positive electrode active material.
`
`[0043]
`325 The positive electrode active material was prepared by mixing com mercially available MnF2,
`YF3, and LiF at a molar ratio of 0.95:0.05:3,3 in an Ar atmosphere, kneading it in a mortar,
`and then calcining it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0044]
`331 (Example 11) A battery was used that was manufactured in the same manner as in Example 1,
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`except that Li3Mn0.95Nb0.05F6 was used as the positive electrode active material.
`
`[0045]
`336 The positive electrode active material was prepared by mixing com mercially available MnF2,
`NbF3, and LiF in an Ar atmosphere at a molar ratio of 0.95:0.05:3.3, kneading in a mortar,
`and then baking at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0046]
`342 (Example 12) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Mo00,05F6 was used as the positive electrode active material.
`
`[0047]
`347 The positive electrode active material was prepared by mixing com mercially available MnF2,
`MoF3, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then calcining it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0048]
`353 (Example 13) A battery was used which was manufactured in the same manner as in Example
`1 except that Li3Mn0.95 W0.05F6 was used as the positive electrode active material.
`
`[0049]
`358 The positive electrode active material was prepared by mixing com mercially available MnF2,
`WE6, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then calcining it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0050]
`364 (Example 14) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Ca0.05F6 was used as the positive electrode active material.
`
`[0051]
`369 The positive electrode active material was prepared by mixing com mercially available MnF2,
`CaF2, and LiF at a molar ratio of 0.95:0,05:3,3 in an Ar atmosphere, kneading in a mortar,
`and then baking at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
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`[0052]
`375 (Example 15) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Sr0.05F6 was used as the positive electrode active material.
`
`[0053]
`380 The positive electrode active material was prepared by mixing com mercially available MnF2,
`SrF2, and LiF at a molar ratio of 0.95:0,05:3,3 in an Ar atmosphere, kneading in a mortar,
`and then baking at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0054]
`386 (Example 16) A battery was used that was manufactured in the same manner as in Example 1
`except that Li3Mn0.95Ba0.05F6 was used as the positive electrode active material.
`
`[0055]
`391 The positive electrode active material was prepared by mixing com mercially available MnF2,
`BaF2, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0056]
`397 (Example 17) A battery was used which was manufactured in the same manner as in Example
`1 except that Li3Mn0.95Al0.05F6 was used as the positive electrode active material.
`
`[0057]
`402 The positive electrode active material was prepared by mixing com mercially available MnF2,
`AIF3, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
`
`[0058]
`408 (Example 18) A battery was used which was manufactured in the same manner as in Example
`1 except that Li3Mn0.95Bi0.05F6 was used as the positive electrode active material,
`
`[0059]
`413 The positive electrode active material was prepared by mixing com mercially available MnF2,
`BiF3, and LiF at a molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneading it in a mortar,
`and then baking it at 750 ° C for 12 hours in an Ar atmosphere. It was synthesized by
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`[0060]
`419 (Example 19) A battery was used which was manufactured in the same manner as in Example
`1 except that Li3Mn0.95 W0.0500.02F5.96 was used as the positive electrode active
`material,
`
`[0061]
`425 For the positive electrode active material, com mercially available MnF2, WF5, and LiF were
`mixed ina molar ratio of 0.95:0.05:3.3 in an Ar atmosphere, kneaded in a mortar, and then
`heated at 750 ° C for 12 hours in a mixed Ar and 02 atmosphere, It was synthesized by
`calcination.
`
`[0062]
`432 (Comparative Example 1) A battery manufactured in the same manner as in Example 1 except
`that LiNiO2 was used as the positive electrode active material was used.
`
`[0063]
`437 The positive electrode active material was synthesized by mixing commercially available NiO
`and LiOH at a molar ratio of 1:1.1, kneading in a mortar, and then baking at 750° C. for 12
`hours in an O 2 atmosphere.
`
`[0064]
`443 The discharge characteristics of the nonaqueous electrolyte secondary battery thus obtained
`were investigated under the following conditions.
`445 The battery was charged to 4.8V at 25° C. with a constant current of 0,01 It.
`446 Thereafter, the battery was discharged at a constant current of 0.01 It, and the energy density
`was measured until the terminal voltage reached 2.5V.
`
`[0065]
`451 Table 1 shows the energy densities of positive electrode active materials produced in
`Examples of the present invention and Comparative Examples,
`453 This indicates that the positive electrode active material used in this example has an
`extremely high energy density,
`
`[0067]
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`458 As described above, it has been found that by using the lithium-containing compound shown
`in the present invention as a positive electrode active material, a non-aqueous electrolyte
`secondary battery having high energy density and good reversibility can be obtained.
`
`[0068]
`464 The non-aqueous electrolyte secondary battery of the present invention has high energy
`density and good reversibility, so it can be used as a small secondary battery used in portable
`electronic devices, as a power source for mobile objects, or as a stationary power source.
`Useful for batteries, etc.
`
`[0069]
`471 1 Battery case 2 Sealing plate 3 Current collector 4 Lithium metal negative electrode 5
`Positive electrode 6 Separator 7 Insulating gasket
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