JP2019179603A - Lithium-sulfur solid battery, positive electrode sheet for battery, negative electrode sheet for battery, cylindrical battery, cylindrical battery with current collector, and laminated battery - Google Patents

Abstract

To provide a novel lithium-sulfur solid battery that is unlikely to cause a solid electrolyte to be cracked even if a thickness of the solid electrolyte is reduced, and ensures good handling.SOLUTION: A lithium-sulfur solid battery 10 includes: a flexible sheet-like sulfur positive electrode 11; a flexible sheet-like lithium negative electrode 12; a solid electrolyte 13 disposed between the sulfur positive electrode 11 and the lithium negative electrode 12; and a flexible lithium ion conductive layer 14, the solid electrolyte 13 being formed in a sheet shape having a thickness of 10 to 500 μm. A positive electrode sheet for a battery, a negative electrode sheet for a battery, a cylindrical battery, a cylindrical battery with a current collector, and a laminated battery are also provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lithium sulfur solid battery, a positive electrode sheet for a battery, a negative electrode sheet for a battery, a cylindrical battery, a cylindrical battery with a current collector, and a laminated battery.

In recent years, electronic devices and communication devices are rapidly becoming portable and cordless. Secondary batteries with high energy density and excellent load characteristics are demanded as power sources for these electronic and communication devices, and the use of lithium secondary batteries with high voltage, high energy density, and excellent cycle characteristics is expanding. is doing.
On the other hand, batteries with a higher energy density are required for the popularization of electric vehicles and the promotion of the use of natural energy. Therefore, development of a new lithium secondary battery that replaces a lithium ion secondary battery that uses a lithium composite oxide such as LiCoO ₂ as a constituent material of the positive electrode is desired.

  Sulfur has a very high theoretical capacity density of 1672 mAh / g, and lithium-sulfur batteries using sulfur as a constituent material of the positive electrode have the possibility of achieving the highest energy density theoretically among the batteries. ing. Therefore, research and development of lithium-sulfur batteries have been actively conducted.

When an organic electrolyte is used as the electrolyte of a lithium-sulfur battery, sulfur molecules and reaction intermediates (for example, lithium polysulfide) are dissolved and diffused in the organic electrolyte during charging and discharging. Thus, there is a problem that the self-discharge and the deterioration of the negative electrode are caused and the battery performance is lowered.
Therefore, in order to solve such problems, a method of modifying the electrolytic solution by adding an acid such as hydrochloric acid or nitric acid to the electrolytic solution (see Patent Document 1), as a constituent material of the positive electrode, Ketjen Black A method using a composite encapsulating sulfur nanoparticles (see Patent Document 2) has been proposed.

JP2013-114920A JP 2012-204332 A

However, in the methods disclosed in Patent Documents 1 and 2, since the electrolyte itself is in a liquid state, it is not possible to completely suppress dissolution of sulfur molecules and reaction intermediates in the electrolytic solution, and a sufficient effect can be obtained. There was no problem.
As a method for solving the problems when such an electrolytic solution is used, there is a method using a solid electrolyte. However, a lithium-sulfur solid battery equipped with a solid electrolyte has not yet been sufficiently technically studied, and there is room for significant improvement.

  For example, the solid electrolyte is preferably a ceramic material. In addition, various reports have reported that it is effective to reduce the thickness of the solid electrolyte in order to improve the energy density of the lithium-sulfur solid state battery. However, since the solid electrolyte made of ceramic is easy to break, from a practical viewpoint, a battery structure using a plate-like member having a certain thickness for securing strength or the like is generally used.

  Problems to be solved by the embodiments of the present invention include a lithium-sulfur solid battery, a positive electrode sheet for a battery, a negative electrode sheet for a battery, and a cylinder that are less likely to cause cracking of the solid electrolyte even when the solid electrolyte is thinned, and can be satisfactorily handled. It is providing a cylindrical battery, a cylindrical battery with a collector, and a laminated battery.

In order to solve the above problems, the present invention provides the following aspects.
The lithium-sulfur solid state battery of the first aspect includes a solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, a sulfur positive electrode formed in a sheet shape and flexibility, and formed in a sheet shape and having flexibility. A lithium negative electrode, a lithium ion conductive layer disposed between the solid electrolyte and the lithium negative electrode, and the sulfur positive electrode and the lithium negative electrode disposed on the opposite side of the lithium ion conductive layer via the fixed electrolyte And a holding member that restricts an increase in the distance between the sulfur positive electrode and the lithium negative electrode, and the sulfur positive electrode is a conductive material that is formed of a conductive material and has many holes that are open on the surface. Containing only the sulfur and the ionic liquid among sulfur, the conductive assistant, the binder and the ionic liquid, or all of the sulfur, the conductive assistant, the binder and the ionic liquid, A positive electrode material accommodated in the hole portion of the electric sheet, and the lithium ion conductive layer is impregnated with an ionic liquid in a flexible sheet-like main body portion which is a porous body or a fiber assembly, and The lithium ion is conducted between the lithium negative electrode and the solid electrolyte.
The positive electrode sheet for a battery according to the second aspect includes a solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, and the sulfur positive electrode formed in a sheet shape and having flexibility, and the sulfur positive electrode is electrically conductive. A conductive sheet that is formed of a material and has many holes that are open on the surface, and only sulfur and ionic liquid among sulfur, conductive assistant, binder, and ionic liquid, or all of sulfur, conductive assistant, binder, and ionic liquid. And having a positive electrode material accommodated in the hole portion of the conductive sheet.
A negative electrode sheet for a battery according to a third aspect includes a solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, a lithium negative electrode formed in a sheet shape and having flexibility, and between the solid electrolyte and the lithium negative electrode. A lithium ion conductive layer disposed on a flexible sheet-like main body, which is a porous body or a fiber assembly, and the lithium negative electrode; It has flexibility to conduct lithium ions with the solid electrolyte.
The cylindrical battery of the fourth aspect is formed by winding the lithium-sulfur solid battery of the first aspect into a cylindrical shape, and the lithium-sulfur solid battery has one of the sulfur positive electrode and the lithium negative electrode on the inner peripheral side, and the other. Are wound in a direction toward the outer peripheral side, and portions adjacent to each other in the radial direction of the cylindrical lithium-sulfur solid battery are in contact with each other.
A cylindrical battery with a current collector according to a fifth aspect includes the cylindrical battery according to the fourth aspect and the sulfur positive electrode that is inserted into a hollow portion inside the cylindrical battery to form an inner peripheral surface of the cylindrical battery. Alternatively, a metal rod-shaped inner current collector that is in contact with the lithium negative electrode, and a metal outer current collector that is in contact with the sulfur positive electrode or the lithium negative electrode that forms the side peripheral surface of the cylindrical battery; Have
The laminated battery of the sixth aspect is formed by laminating two or more selected from the lithium-sulfur solid battery of the first aspect, the positive electrode sheet for the battery of the second aspect, and the negative electrode sheet for the battery of the third aspect. It is a thing.
The solid electrolyte may be formed of an oxide material.

  According to the lithium-sulfur solid battery according to the embodiment of the present invention, a sheet-like solid electrolyte having a thickness of 10 to 500 μm is formed by sandwiching a sheet-like solid electrolyte and a lithium ion conductive layer between a sulfur positive electrode and a lithium negative electrode. Even so, cracking of the solid electrolyte hardly occurs. For this reason, the lithium sulfur solid state battery according to the embodiment of the present invention can ensure good handling properties.

A sheet-like solid electrolyte having a thickness of 10 to 500 μm is easy to ensure flexibility.
The lithium ion conductive layer can ensure flexibility by a configuration in which a flexible main body which is a porous body or a fiber assembly is impregnated with an ionic liquid.
For this reason, the lithium-sulfur solid battery according to the embodiment of the present invention has a flexible structure in which a sheet-like solid electrolyte and a lithium ion conductive layer are sandwiched between a flexible sulfur positive electrode and a flexible lithium negative electrode. Therefore, it is possible to secure various properties and to adopt various usage forms such as bending.

The battery positive electrode sheet according to an aspect of the present invention can ensure flexibility by the flexibility of each of a sheet-like solid electrolyte having a thickness of 10 to 500 μm and a flexible sheet-like sulfur positive electrode.
The battery negative electrode sheet according to an embodiment of the present invention can ensure flexibility by the flexibility of each of a sheet-like solid electrolyte having a thickness of 10 to 500 μm, a lithium ion conductive layer, and a flexible sheet-like lithium negative electrode. .

  A laminated battery constituted by laminating two or more selected from a lithium-sulfur solid battery, a positive electrode sheet for a battery, and a negative electrode sheet for a battery is selected and laminated from a lithium-sulfur solid battery, a positive electrode sheet for a battery, and a negative electrode sheet for a battery. Depending on the number of batteries or sheets, the size and output can be adjusted flexibly.

It is sectional drawing which shows typically an example of the principal part of the lithium sulfur solid battery which concerns on embodiment of this invention. It is a perspective view which shows an example of the cylindrical battery formed by winding the lithium sulfur solid battery of FIG. 1 in the shape of a cylinder, and the cylindrical battery with a current collector formed using the cylindrical battery. It is a figure which shows the structure which looked at the cylindrical battery of FIG. 2 from the axial direction one side. It is the elements on larger scale of the cylindrical battery of FIG. It is sectional drawing which shows an example of the positive electrode sheet for batteries. It is sectional drawing which shows an example of the negative electrode sheet for batteries.

<< Lithium sulfur solid battery >>
Hereinafter, a lithium-sulfur solid battery according to an embodiment of the present invention will be described with reference to the drawings.
In addition, in order to make the features of the present invention easy to understand, the drawings used in the following description may show the main parts in an enlarged manner for convenience, and the dimensional ratios of the respective components are the same as the actual ones. Not necessarily.

FIG. 1 is a front sectional view showing a main structure of a lithium-sulfur solid battery 10 according to an embodiment of the present invention.
A lithium-sulfur solid battery 10 shown in FIG. 1 includes a sulfur positive electrode 11, a lithium negative electrode 12, a solid electrolyte 13, a lithium ion conductive layer 14, and a holding member 15.
The solid electrolyte 13 and the lithium ion conductive layer 14 are sandwiched between the sulfur positive electrode 11 and the lithium negative electrode 12.
The lithium ion conductive layer 14 is sandwiched between the solid electrolyte 13 and the lithium negative electrode 12.

In the lithium-sulfur solid battery 10 shown in FIG. 1, the sulfur positive electrode 11, the lithium negative electrode 12, and the solid electrolyte 13 are each formed in a flexible sheet shape.
The lithium-sulfur solid battery 10 has a structure in which a sulfur positive electrode 11, a solid electrolyte 13, a lithium ion conductive layer 14, and a lithium negative electrode 12 are laminated in this order.

The lithium ion conductive layer 14 may be a porous material or a fibrous material in which fibrous materials are aggregated to form a layer (in this specification, sometimes referred to as “fiber aggregate”). A flexible sheet-like main body is impregnated with an ionic liquid.
In the present specification, a portion of the lithium ion conductive layer 14 that has the void portion, holds the ionic liquid, and maintains the shape of the lithium ion conductive layer is referred to as a “main body portion”. That is, the lithium ion conductive layer 14 includes the main body portion and the ionic liquid held by the main body portion.

    Examples of the flexible sheet-like main body portion include paper, a porous body made of synthetic resin, and a fiber assembly made of synthetic resin or glass fibers. The main body has a structure in which a large number of voids penetrating in the thickness direction exist in a state before impregnation with the ionic liquid.

The thickness direction of the main body matches the thickness direction of the lithium ion conductive layer 14.
The ionic liquid of the lithium ion conductive layer 14 is held in the gap of the main body.
The void portion holding the ionic liquid is formed from one surface (sometimes referred to as a “first surface” in this specification) 14a of the lithium ion conductive layer 14 to the other surface (in the present specification, “ It may be referred to as “the second surface”) to reach 14b.
Therefore, a liquid substance or a fine substance can be moved between the lithium negative electrode 12 and the solid electrolyte 13 via the lithium ion conductive layer 14.

Furthermore, lithium ions can be dissolved in the ionic liquid of the lithium ion conductive layer 14. Thus, through the lithium ion conductive layer 14, in between the lithium anode 12 and the solid electrolyte 13 (the direction of the thickness T ₁₄ of the lithium ion-conducting layer of 14), become easily conducting lithium ions Yes.

  In the lithium-sulfur solid battery 10, due to the presence of the lithium ion conductive layer 14, the ionic liquid in the lithium ion conductive layer 14 causes the lithium ion conductive layer 14, in other words, between the lithium negative electrode 12 and the solid electrolyte 13, , The precipitation of metallic lithium is suppressed. Here, “precipitation of metallic lithium in the lithium ion conductive layer 14 is suppressed” means that “no metallic lithium is precipitated in the lithium ion conductive layer 14 or no metallic lithium is deposited in the lithium ion conductive layer 14. Even if it precipitates, it means that the amount of precipitation is very small. Accordingly, the lithium ion conductive layer 14 smoothly conducts lithium ions between the lithium negative electrode 12 and the solid electrolyte 13. In addition, by suppressing the deposition of metallic lithium in this way, the deposition of metallic lithium is also suppressed in the solid electrolyte 13. That is, in the lithium-sulfur solid battery 10, continuous deposition of metallic lithium from the lithium ion conductive layer 14 to the sulfur positive electrode 11 via the solid electrolyte 13 is suppressed. As a result, in the lithium-sulfur solid battery 10, for example, when charging / discharging is performed, occurrence of short circuit and cracking of the solid electrolyte can be suppressed.

In the lithium-sulfur solid battery 10, for example, the sulfur positive electrode 11 and the lithium negative electrode 12 are further provided with terminals for connection to external circuits, respectively.
In the lithium-sulfur solid battery 10, the entire laminated structure of the above-described sulfur positive electrode 11, solid electrolyte 13, lithium ion conductive layer 14, and lithium negative electrode 12 is housed in a container as necessary.
Further, the lithium-sulfur solid battery 10 further includes a mechanism (leakage suppression mechanism) that suppresses leakage of the ionic liquid in the lithium ion conductive layer 14 to the outside of the lithium-sulfur solid battery 10 as necessary. Also good. For example, the container may also serve as such a leakage suppression mechanism.
Next, the configuration of each layer of the lithium-sulfur solid battery of the present embodiment will be described in detail.

First, the sulfur positive electrode will be described in detail.
The sulfur positive electrode in the lithium-sulfur solid battery of the present embodiment is not particularly limited as long as it contains sulfur and functions as a positive electrode.

However, as a preferable sulfur positive electrode 11, one having a conductive sheet having a large number of hole portions opened on the surface and a positive electrode material accommodated in the hole portions of the conductive sheet can be mentioned.
A conductive sheet having flexibility is adopted. The sulfur positive electrode 11 in which the positive electrode material is accommodated in the hole portion of the conductive sheet is formed in a flexible sheet shape.

The positive electrode material contains only sulfur, sulfur, conductive auxiliary, binder and ionic liquid, only sulfur and ionic liquid, or contains all sulfur, conductive auxiliary, binder and ionic liquid. It is.
The positive electrode material may be present so as to cover not only the hole portion of the conductive sheet but also a part or the whole of the outer peripheral surface of the conductive sheet.
Hereinafter, these constituent materials of the sulfur positive electrode will be described in detail.
First, a sulfur positive electrode having a positive electrode material containing all of sulfur, a conductive additive, a binder, and an ionic liquid will be described.

[Conductive sheet]
The hole part of an electroconductive sheet hold | maintains components other than the electroconductive sheet of a sulfur positive electrode, ie, a positive electrode material. The conductive sheet can function as a positive electrode current collector.
Moreover, the hole part of an electroconductive sheet is opened to the electroconductive sheet surface, and it becomes possible to hold | maintain these components by adding each component, such as sulfur later, to an electroconductive sheet. Yes.

The shape of the hole of the conductive sheet is not particularly limited as long as the above conditions are satisfied.
For example, the hole may be communicated with one or more other holes, or may be independent without communicating with other holes.
Moreover, the hole part may penetrate the electroconductive sheet, and the non-penetrating thing which does not penetrate the electroconductive sheet may be sufficient as it.

Examples of the form of the conductive sheet include a fiber aggregate (a fibrous material in which conductive fibrous materials are aggregated to form a layer).
The fiber assembly that constitutes the conductive sheet may be, for example, a structure in which fibrous materials are entangled with each other, or a structure in which fibrous materials are stacked regularly or irregularly. May be.
The hole part of the electroconductive sheet which is a fiber assembly refers to what opens to the surface of an electroconductive sheet among the area | regions where the fibrous material in a fiber assembly does not exist, such as the area | region between the fibrous materials spaced apart from each other.

The hole portion of the conductive sheet may be embedded with a positive electrode material without a gap, or there may be a certain amount of voids that are not embedded with the positive electrode material.
The sulfur positive electrode including a conductive sheet that is a fiber assembly has a configuration in which a fibrous material constituting the fiber assembly is embedded in a positive electrode material filled in a region where no fibrous material exists in the fiber assembly. .

The constituent material of the conductive sheet may be conductive as long as it does not have reactivity with sulfur.
More specifically, examples of the constituent material of the conductive sheet include carbon, metal (single metal, alloy), and the like.
Especially, as a preferable constituent material of a conductive sheet, the constituent material of a positive electrode electrical power collector is mentioned, More specifically, carbon, copper, aluminum, titanium, nickel, stainless steel etc. are mentioned, for example.

  The constituent material of the conductive sheet may be only one kind, or two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected according to the purpose.

  Examples of preferable conductive sheets include carbon felt and carbon cloth.

  The thickness of the conductive sheet is not particularly limited, and may be set as appropriate according to the purpose of the applied battery. Usually, the thickness of the conductive sheet is preferably 50 to 30000 μm, and more preferably 100 to 3000 μm.

  In addition, when the thickness of the conductive sheet clearly varies depending on the portion of the conductive sheet, such as when the degree of unevenness on the surface of the conductive sheet is high, the maximum thickness is the thickness of the conductive sheet. (The thickness of the thickest part of the conductive sheet is the thickness of the conductive sheet). This applies not only to the conductive sheet but also to the thicknesses of all layers (a sulfur positive electrode, a lithium negative electrode, and a solid electrolyte described later).

[Conductive aid]
The conductive auxiliary agent may be a known one, and specific examples thereof include graphite (graphite); carbon black such as ketjen black and acetylene black; carbon nanotube; graphene; fullerene and the like.
Only 1 type may be sufficient as the conductive support agent which a sulfur positive electrode contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be arbitrarily selected according to the objective.

  In the sulfur positive electrode, the ratio of the total content of sulfur and conductive additive to the total content of sulfur, conductive additive, binder and ionic liquid ([total content of sulfur and conductive additive in sulfur positive electrode (part by mass)] / [Total content of sulfur in the positive electrode, conductive additive, binder and ionic liquid (parts by mass)] × 100) is not particularly limited, but is preferably 60 to 95% by mass, and 70 to 85% by mass. It is more preferable that The charge / discharge characteristic of a battery improves more because the ratio of the said total content is more than the said lower limit. The effect by using components other than sulfur and a conductive support agent is more notably acquired because the ratio of the said total content is below the said upper limit.

  In the sulfur positive electrode, the mass ratio of [sulfur content (parts by mass)]: [content of conductive additive (parts by mass)] is not particularly limited, but is preferably 30:70 to 70:30, It is more preferable that it is 45: 55-65: 35. The charge / discharge characteristics of the battery are further improved as the sulfur content ratio is higher, and the conductivity of the sulfur positive electrode is further improved as the conductive additive content ratio is higher.

In the sulfur positive electrode, sulfur and the conductive additive may form a composite.
For example, sulfur and a carbon-containing material (such as ketjen black) are mixed and fired to obtain a sulfur-carbon composite. Such a composite is also suitable as a component contained in the sulfur positive electrode.

[binder]
The binder may be a known one, and specific examples include, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylic acid (PAA), Lithium polyacrylate (PAALi), styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene glycol (PEG), carboxymethylcellulose (CMC), polyacrylonitrile (PAN), polyimide (PI) Etc.
The binder contained in the sulfur positive electrode may be only one type, or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose.

  In the sulfur positive electrode, the ratio of the binder content to the total content of sulfur, conductive additive, binder and ionic liquid ([sulfur positive electrode binder content (parts by mass)] / [sulfur positive electrode sulfur, conductive auxiliary agent The total content (parts by mass) of the binder and the ionic liquid] × 100) is not particularly limited, but is preferably 3 to 15% by mass, and more preferably 5 to 9% by mass. The structure of a sulfur positive electrode can be more stably maintained because the ratio of the said content is more than the said lower limit. When the content ratio is equal to or lower than the upper limit value, the charge / discharge characteristics of the battery are further improved.

[Ionic liquid]
The ionic liquid contained in the sulfur positive electrode is a component for easily moving lithium ions. The ionic liquid is excellent in high-temperature stability and can easily move lithium ions. When the sulfur positive electrode contains the ionic liquid, the ionic liquid moves lithium ions between the sulfur positive electrode and the solid electrolyte, although the contact area between the sulfur positive electrode and the solid electrolyte is small. Therefore, although the solid battery using such a sulfur positive electrode uses a solid electrolyte, the interface resistance value at the sulfur positive electrode interface is reduced, and the battery characteristics are more excellent.

The ionic liquid can be appropriately selected from, for example, known ones.
However, as the ionic liquid, for example, those having lower sulfur solubility in a temperature range of less than 170 ° C. are preferable, and those that do not dissolve sulfur are particularly preferable.

  Examples of the ionic liquid include ionic compounds that are liquid at a temperature of less than 170 ° C., solvated ionic liquids, and the like.

(Ionic compounds that are liquid at temperatures below 170 ° C)
The cation part constituting the ionic compound may be either an organic cation or an inorganic cation, but is preferably an organic cation.
The anion part constituting the ionic compound may be either an organic anion or an inorganic anion.

Among the cation moieties, examples of the organic cation include an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, a phosphonium cation, and an ammonium cation. , Sulfonium cation and the like.
However, the organic cation is not limited to these.

Among the anion moieties, examples of the organic anion include alkyl sulfate anions such as methyl sulfate anion (CH ₃ SO ₄ ⁻ ) and ethyl sulfate anion (C ₂ H ₅ SO ₄ ⁻ );
Tosylate anion (CH ₃ C ₆ H ₄ SO ₃ ⁻ );
Alkanesulfonate anions such as methanesulfonate anion (CH ₃ SO ₃ ⁻ ), ethanesulfonate anion (C ₂ H ₅ SO ₃ ⁻ ), butanesulfonate anion (C ₄ H ₉ SO ₃ ⁻ );
Trifluoromethanesulfonate anion (CF ₃ SO ₃ ⁻ ), pentafluoroethanesulfonate anion (C ₂ F ₅ SO ₃ ⁻ ), heptafluoropropanesulfonate anion (C ₃ H ₇ SO ₃ ⁻ ), nonafluorobutanesulfonate anion (C ₄₎ H ₉ SO ₃ ^-) perfluoroalkane sulfonate anions such as (perfluoroalkanesulfonate anion);
Bis (trifluoromethanesulfonyl) imide anion ((CF ₃ SO ₂ ) N ⁻ ), bis (nonafluorobutanesulfonyl) imide anion ((C ₄ F ₉ SO ₂ ) N ⁻ ), nonafluoro-N-[(trifluoromethane) Sulfonyl] butanesulfonylimide anion ((CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) N ⁻ ), N, N-hexafluoro-1,3-disulfonylimide anion (SO ₂ CF ₂ CF ₂ CF ₂ SO ₂ N ^-) perfluoroalkanesulfonyl anion such as (perfluoroalkanesulfonylimide anion);
Acetate anion (CH ₃ COO ⁻ );
Hydrogen sulfate anion (HSO ₄ ⁻ ); and the like.
However, the organic anion is not limited to these.

Among the anion moieties, examples of inorganic anions include bis (fluorosulfonyl) imide anion (N (SO ₂ F) ₂ ⁻ ); hexafluorophosphate anion (PF ₆ ⁻ ); tetrafluoroborate anion (BF ₄ ⁻ ). Halide ions such as chloride ions (Cl ⁻ ), bromide ions (Br ⁻ ), iodide ions (I ⁻ ), tetrachloroaluminate anions (AlCl ₄ ⁻ ), thiocyanate anions (SCN ⁻ ), etc. Is mentioned.
However, the inorganic anion is not limited to these.

  Examples of the ionic compound include those composed of a combination of any one of the above cation moieties and any one of the above anion moieties.

  Examples of the ionic liquid in which the cation portion is an imidazolium cation include 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1 -Methyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium chloride, 1-butyl-3- Methyl imidazolium chloride, 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methanesulfonate, 1,2,3-trimethylimidazolium methyl sulfate, methyl imi Zorium chloride, methyl imidazolium hydrogen sulfate, 1-ethyl-3-methyl imidazolium hydrogen sulfate, 1-butyl-3-methyl imidazolium hydrogen sulfate, 1-butyl-3-methyl imidazolium hydrogen sulfate, 1-ethyl-3-methylimidazolium tetrachloroaluminate, 1-butyl-3-methylimidazolium tetrachloroaluminate, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-butyl-3-methyl Imidazolium thiocyanate, 1-ethyl-2,3-dimethyl-imidazolium ethylsulfate, and the like.

  Examples of the ionic liquid whose cation portion is a pyridinium cation include 1-butylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, and the like.

  Examples of the ionic liquid in which the cation portion is a pyrrolidinium cation include 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide and 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl). An imide etc. are mentioned.

  Examples of the ionic liquid in which the cation portion is a phosphonium cation include tetrabutylphosphonium bis (trifluoromethanesulfonyl) imide, tributyldodecylphosphonium bis (trifluoromethanesulfonyl) imide, and the like.

  Examples of the ionic liquid whose cation portion is an ammonium cation include methyltributylammonium methylsulfate, butyltrimethylammonium bis (trifluoromethanesulfonyl) imide, trimethylhexylammonium bis (trifluoromethanesulfonyl) imide, and the like.

(Solvated ionic liquid)
Preferred examples of the solvated ionic liquid include those composed of a glyme-lithium salt complex.

Examples of the lithium salt in the glyme-lithium salt complex include lithium bis (fluorosulfonyl) imide (LiN (SO ₂ F) ₂ , which may be abbreviated as “LiFSI” in this specification), lithium bis ( Trifluoromethanesulfonyl) imide (LiN (SO ₂ CF ₃ ) ₂ , which may be abbreviated as “LiTFSI” in this specification).

Examples of the glyme in the glyme-lithium salt complex include triethylene glycol dimethyl ether (CH ₃ (OCH ₂ CH ₂ ) ₃ OCH ₃ , triglyme), tetraethylene glycol dimethyl ether (CH ₃ (OCH ₂ CH ₂ ) ₄ OCH ₃ , Tetraglyme) and the like.

  Examples of the glyme-lithium salt complex include a complex composed of one molecule of glyme and one molecule of lithium salt, but the glyme-lithium salt complex is not limited thereto.

  The glyme-lithium salt complex is obtained by, for example, mixing lithium salt and glyme so that the molar ratio of lithium salt (mol): glyme (mol) is preferably 10:90 to 90:10. Can be made.

  Preferred examples of the glyme-lithium salt complex include triglyme-LiFSI complex, tetraglyme-LiFSI complex, triglyme-LiTFSI complex, tetraglyme-LiTFSI complex and the like.

  The ionic liquid which a sulfur positive electrode contains may be only 1 type, 2 or more types, and when it is 2 or more types, those combinations and ratios can be arbitrarily selected according to the objective.

  Among the above, the ionic liquid contained in the sulfur positive electrode is preferably a solvated ionic liquid comprising a glyme-lithium salt complex.

  In the sulfur positive electrode, the ratio of the content of ionic liquid to the total content of sulfur, conductive additive, binder and ionic liquid ([content of ionic liquid of sulfur positive electrode (part by mass)] / [sulfur of sulfur positive electrode, conductive The total content (parts by mass) of the auxiliary agent, binder and ionic liquid] × 100) is not particularly limited, but is preferably 5 to 20% by mass, and more preferably 9 to 15% by mass. The electroconductivity of a sulfur positive electrode improves more because the ratio of the said content is more than the said lower limit. When the content ratio is equal to or lower than the upper limit value, the charge / discharge characteristics of the battery are further improved.

[Other ingredients]
As long as the sulfur positive electrode does not impair the effects of the present invention, as a constituent component other than the conductive sheet, in addition to sulfur, a conductive auxiliary agent, a binder and an ionic liquid, other components (excluding the solvent described later) are included. You may contain.
The other components are not particularly limited and can be arbitrarily selected depending on the purpose.
The other component contained in the sulfur positive electrode may be only one type or two or more types, and in the case of two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose.

  In the sulfur positive electrode, the ratio of the content of other components to the total content of sulfur, conductive additive, binder and ionic liquid ([content of other components of sulfur positive electrode (part by mass)] / [sulfur positive electrode Sulfur, conductive assistant, binder and ionic liquid total content (parts by mass)] × 100) is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, It is more preferably 3% by mass or less, particularly preferably 1% by mass or less, and may be 0% by mass.

  In the sulfur positive electrode, the ratio of the total mass of sulfur, conductive additive, binder and ionic liquid to the mass of the conductive sheet ([total mass of sulfur, conductive auxiliary, binder and ionic liquid] / [mass of conductive sheet] X100) is preferably 15 to 45% by mass, and more preferably 25 to 40% by mass.

<Method for producing sulfur positive electrode>
A known sulfur positive electrode such as a sulfur positive electrode having a positive electrode active material layer on a current collector (positive electrode current collector) described above may be produced by a known method.
On the other hand, the sulfur positive electrode provided with the conductive sheet is manufactured by, for example, impregnating the conductive sheet with a positive electrode material (positive electrode material forming composition) containing sulfur, a conductive additive, a binder and an ionic liquid. Can be manufactured by the method. The manufacturing method may further include other steps such as a step of drying the impregnated positive electrode material-forming composition.
However, in this method for producing a sulfur positive electrode, when the positive electrode material forming composition impregnated in the conductive sheet contains an organic solvent that generates a flammable gas, the step of impregnating the positive electrode material forming composition in the conductive sheet Thereafter, the organic solvent that generates the flammable gas is removed from the positive electrode material-forming composition by a drying process or distillation.
Hereinafter, the manufacturing method of such a sulfur positive electrode is demonstrated.

[Positive electrode material]
As a preferable positive electrode material formation composition, what contains sulfur, a conductive support agent, a binder, an ionic liquid, a solvent, and the said other component as needed is mentioned, for example.

The said solvent is a component for melt | dissolving or disperse | distributing each components, such as above-mentioned sulfur, and providing moderate fluidity | liquidity to a positive electrode material formation composition.
In the present specification, unless otherwise specified, any ionic liquid is not included in the solvent (all ionic liquids are not handled as solvents).

A solvent can be arbitrarily selected according to the type of each component such as sulfur described above, and an organic solvent is preferable.
Examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol, and 2-propanol; amides such as N-methylpyrrolidone (NMP) and N, N-dimethylformamide (DMF); and ketones such as acetone. Can be mentioned.
The solvent contained in the positive electrode material (positive electrode material-forming composition) may be only one type, or two or more types, and in the case of two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose. .
The content of the solvent in the positive electrode material-forming composition is not particularly limited, and can be appropriately adjusted according to the type of components other than the solvent.

  Ratio of sulfur content to total content of components other than solvent in positive electrode material ([sulfur content (mass) of positive electrode material] / [total content of components other than solvent of positive electrode material (parts by mass) )] × 100) is the ratio of the sulfur content to the total content of sulfur, conductive additive, binder, ionic liquid and other components in the sulfur positive electrode ([sulfur positive electrode sulfur content (parts by mass) ]] / [Total content of sulfur positive electrode, sulfur, conductive additive, binder, ionic liquid and other components (parts by mass)] × 100). This is the same for conductive aids, binders, ionic liquids and other components other than sulfur.

The positive electrode material-forming composition can be obtained by blending each component such as sulfur described above.
The order of addition at the time of blending each component is not particularly limited, and two or more components may be added simultaneously.
In the case of using a solvent, the solvent is mixed with any component other than the solvent (that is, any of the above-mentioned sulfur, conductive additive, binder, ionic liquid, and other components described above), and this component is mixed. You may use it by diluting beforehand, and you may use it by mixing a solvent with these components, without diluting any components other than the above-mentioned solvent beforehand.

The method of mixing each component at the time of blending is not particularly limited, and a method of mixing by rotating a stir bar, a stirring bar or a stirring blade, a method of mixing using a mixer, a method of mixing by adding ultrasonic waves, etc. are known. What is necessary is just to select suitably from these methods.
The temperature and time during addition and mixing of each component are not particularly limited as long as each component does not deteriorate. Usually, it is preferable that the temperature at the time of mixing is 15-30 degreeC.

  The positive electrode material-forming composition obtained by adding and mixing each component may be used as it is for impregnation of the conductive sheet, for example, by removing some of the added solvent by distillation or the like. What was obtained by performing additional operations may be used for impregnation of the conductive sheet.

The impregnation of the positive electrode material-forming composition into the conductive sheet is performed by, for example, a method of applying the liquid positive electrode material-forming composition to the conductive sheet, a method of immersing the conductive sheet in the liquid positive electrode material, and the like. It can be carried out.
The positive electrode material-forming composition can be applied to the conductive sheet by a known method.
The temperature of the positive electrode material impregnated into the conductive sheet is not particularly limited, but may be, for example, 15 to 30 ° C. However, this is an example of the temperature.

The positive electrode material-forming composition can be dried by a known method under normal pressure or reduced pressure. For example, although it can dry preferably on 70-90 degreeC and the conditions for 8 to 24 hours, drying conditions are not limited to this.
In addition, the sulfur positive electrode uses what removed the organic solvent of the positive electrode material formation composition impregnated with the electroconductive sheet by drying, distilling, etc. for the assembly of the lithium sulfur solid battery 10.

Next, the sulfur positive electrode which has the positive electrode material which contains only sulfur among sulfur, a conductive support agent, a binder, and an ionic liquid in the hole part of an electroconductive sheet is demonstrated.
In this method for producing a sulfur positive electrode, a conductive sheet is impregnated by filling holes in the conductive sheet with sulfur in a molten state or a sulfur solution obtained by dissolving sulfur in a solvent. When the electrically conductive sheet is impregnated with sulfur in a heat-melted state, a sulfur positive electrode having a structure in which sulfur is accommodated in the hole is obtained by cooling and solidifying the heat-melted sulfur impregnated in the electrically conductive sheet.
When impregnating a conductive sheet with a sulfur solution, after impregnating the conductive sheet with the sulfur solution, the sulfur positive electrode having a structure in which sulfur is contained in the hole is obtained by removing the solvent in the drying step. .

Next, the sulfur positive electrode which has the positive electrode material which contains only sulfur and an ionic liquid among sulfur, a conductive support agent, a binder, and an ionic liquid in the hole part of an electroconductive sheet is demonstrated.
As the ionic liquid of the positive electrode material, the same ionic liquid as that which can be adopted in the positive electrode material containing all of sulfur, a conductive additive, a binder and an ionic liquid can be adopted.

In an example of a method for producing a sulfur positive electrode having this positive electrode material, first, a sulfur positive electrode having a positive electrode material containing only sulfur among sulfur, a conductive additive, a binder and an ionic liquid in a hole portion of the conductive sheet is produced. Next, by immersing the sulfur positive electrode in the ionic liquid, applying the ionic liquid to the sulfur positive electrode, etc., the void portion in the hole portion of the conductive sheet filled with the ionic liquid is filled, and the hole portion is filled with the ionic liquid. A sulfur positive electrode configured to contain sulfur and ionic liquid is obtained.
However, in this method for producing a sulfur positive electrode, a mixed solution obtained by mixing a solvent with an ionic liquid may be filled in the voids in the holes of the conductive sheet. When using a mixed solution in which an ionic liquid is mixed with an organic solvent that generates a flammable gas, the organic solvent is removed from the mixed solution by a drying process or distillation after the step of impregnating the conductive sheet with the mixed liquid. To do.

  Regardless of the type of the sulfur positive electrode, the thickness of the sulfur positive electrode is not particularly limited, and may be appropriately set according to the purpose of the battery to be applied. The thickness of the sulfur positive electrode is preferably 50 to 30000 μm, and more preferably 100 to 3000 μm.

Next, the solid electrolyte 13 will be described.
The constituent material of the solid electrolyte 13 may be any of a crystalline material, an amorphous material, and a glass material.
More specifically, as a constituent material of the solid electrolyte 13, for example, a material that does not contain sulfide and contains an oxide (sometimes referred to as “oxide-based material” in this specification), at least a sulfide. (In this specification, it may be referred to as “sulfide-based material”) and the like.

Examples of the oxide-based material include Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ), Li _2.9 PO _3.3 N _0.46 (LIPON), and La _0.51 Li _0.34 TiO _2.94. , Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ , 50Li ₄ SiO ₄ .50Li ₃ BO ₃ , Li _3.6 Si _0.6 P _0.4 O ₄ , Li _1.07 Al _{0 .69} Ti _1.46 (PO ₄ ) ₃ , Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ , Li ₅ La ₃ Ta ₂ O ₁₂ , Li _0.33 La _0.55 TiO ₃ ( LLT) and the like.
Examples of the oxide-based material include a material obtained by adding (doping) an element such as aluminum, tantalum, niobium, or bismuth to a composite oxide such as Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ). It is done. Here, the element to be added may be only one kind, or may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected according to the purpose.

Examples of the sulfide-based materials, for _{example, Li 10 GeP 2 S 12 (} LGPS), Li 3.25 Ge 0.25 P 0.75 S 4, 30Li 2 S · 26B 2 S 3 · 44LiI, 63Li 2 S · 36SiS ₂ · 1Li ₃ PO ₄ , 57Li ₂ S · 38SiS ₂ · 5Li ₄ SiO ₄ , 70Li ₂ S · 30P ₂ S ₅ (LIISPS), 50Li ₂ S · 50GeS ₂ , Li ₇ P ₃ S ₁₁ , Li _3.25 P _0.95 S ₄ or the like.

  The constituent material of the solid electrolyte 13 may be only one type, or two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose.

  The constituent material of the solid electrolyte 13 is preferably the oxide-based material from the viewpoint that the solid electrolyte 13 having high stability in the air and high density can be produced.

  The thickness of the solid electrolyte 13 is not particularly limited, and may be set as appropriate according to the purpose of the applied battery. The thickness of the solid electrolyte 13 is preferably 10 to 1200 μm. When the thickness of the solid electrolyte is equal to or more than the lower limit, the manufacturing and handling properties are improved. When the thickness of the solid electrolyte is equal to or less than the upper limit value, the resistance value of the lithium sulfur solid battery is further reduced.

  The solid electrolyte 13 can be manufactured, for example, by selecting a raw material such as a metal oxide, a metal hydroxide, or a metal sulfide according to the intended type and firing the raw material. What is necessary is just to set the usage-amount of a raw material suitably considering the atomic ratio of each metal in the solid electrolyte 13, etc. FIG.

The solid electrolyte 13 is manufactured, for example, by firing a molded body that is entirely molded with powdered powder compacts. Moreover, as a manufacturing method of the solid electrolyte 13, for example, a plurality of sheets (hereinafter, also referred to as “compact sheets”) prepared by compacting a powdery material may be stacked, fired, and integrated.
Further, the solid electrolyte 13 may be applied by drying a composition obtained by dispersing the powder after firing of the raw material in a solvent to the sulfur positive electrode 11 or the main body portion of the lithium ion conductive layer 14 before impregnating the ionic liquid, or drying. Separately, a layered product obtained by applying the composition to a coated material such as a plate material and drying can be peeled off from the coated material and used. It is also possible to add a binder, an electrolytic solution, and the like to the composition depending on the purpose.

The sheet-like solid electrolyte 13 having a thickness of 10 to 500 μm can ensure flexibility.
The solid electrolyte 13 may be curved by being sandwiched between the flexible sheet-like sulfur positive electrode 11 and the flexible sheet-like lithium negative electrode 12 together with the flexible lithium ion conductive layer 14. It is hard to break and can be bent so as to follow the sulfur positive electrode 11, the lithium negative electrode 12 and the lithium ion conductive layer 14.

As the lithium negative electrode 12, a well-known lithium negative electrode used in various batteries can be used.
The thickness of the lithium negative electrode is preferably 10 to 2000 μm and more preferably 100 to 1000 μm in consideration of bending bendability.

Next, the lithium ion conductive layer 14 will be described.
As described above, the lithium ion conductive layer in the lithium-sulfur solid battery of this embodiment is a layer that contains an ionic liquid and conducts lithium ions between the lithium negative electrode and the solid electrolyte.
As described above, the lithium ion conductive layer includes a main body portion and an ionic liquid.

[Main unit]
As said main part of a lithium ion conductive layer, a porous body, a fiber assembly, etc. are mentioned as above-mentioned.
The main part of the lithium ion conductive layer is preferably one that does not react with the lithium negative electrode, does not dissolve, and does not deteriorate under the temperature conditions during operation of the lithium sulfur solid battery. Here, “deterioration of the main body” means that the composition of the components of the main body changes. The temperature during operation of the lithium-sulfur solid battery can be appropriately set according to the type of the sulfur positive electrode. When a known sulfur positive electrode or sulfur positive electrode (I) is used, the temperature during operation of the lithium-sulfur solid battery is, for example, preferably 110 ° C. or less, more preferably 100 ° C. or less. Accordingly, the main body of the lithium ion conductive layer in this case is preferably stable under a temperature condition of about 120 ° C., for example. On the other hand, when the sulfur positive electrode (II) is used, the temperature during operation of the lithium sulfur solid battery is preferably 110 to 160 ° C. Accordingly, the main body portion of the lithium ion conductive layer in this case is preferably stable under such temperature conditions.

In such a main body, examples of the constituent material of the porous body or fiber assembly include synthetic resin, glass, paper, and the like, and synthetic resin or glass is preferable.
Especially, it is more preferable that the constituent material of the main body is polyimide or glass. That is, the lithium ion conductive layer more preferably contains polyimide or glass as a constituent material.

  The constituent material of the main body part of the lithium ion conductive layer may be only one type, or two or more types, and in the case of two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose.

[Ionic liquid]
Examples of the ionic liquid contained in the lithium ion conductive layer include the same ionic liquid as that contained in the above-described sulfur positive electrode (for example, an ionic compound that is liquid at a temperature of less than 170 ° C., a solvated ionic liquid, etc.).

  The ionic liquid contained in the lithium ion conductive layer may be only one kind, or two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected according to the purpose.

  The ionic liquid contained in the lithium ion conductive layer may be the same as or different from the ionic liquid contained in the above-described sulfur positive electrode.

  The ionic liquid contained in the lithium ion conductive layer is preferably a solvated ionic liquid comprising a glyme-lithium salt complex. When the lithium ion conductive layer contains such an ionic liquid, the effect of suppressing the precipitation of metallic lithium in the solid electrolyte is further enhanced.

The content of the ionic liquid in the lithium ion conductive layer is not particularly limited.
However, the ratio of the total volume of the ionic liquid held in the lithium ion conductive layer to the total volume of the voids in the main body of the lithium ion conductive layer ([total of ionic liquid held in the lithium ion conductive layer Volume] / [total volume of voids in the main body of the lithium ion conductive layer] × 100) is preferably 80 to 120% by volume at room temperature. The said ratio is more than the said lower limit, and the precipitation inhibitory effect of metallic lithium in a solid electrolyte becomes higher. The excessive use of an ionic liquid is suppressed because the said ratio is below the said upper limit.
The reason why the ratio can be larger than 100% by volume is that an ionic liquid can be present in the lithium ion conductive layer in addition to the voids of the main body.
In the present specification, “normal temperature” means a temperature that is not particularly cooled or heated, that is, a normal temperature, and includes a temperature of 15 to 25 ° C., for example.

The lithium ion conductive layer may be composed of one layer (single layer), or may be composed of two or more layers. When the lithium ion conductive layer is composed of a plurality of layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited.
In the present specification, not only the lithium ion conductive layer, but “a plurality of layers may be the same or different from each other” means “all layers may be the same or all layers. May be different, or only a part of the layers may be the same, ”and“ a plurality of layers are different from each other ”means that“ at least one of the constituent material and thickness of each layer is the same. Means different.

The thickness of the lithium ion conductive layer (for example, the thickness T ₁₄ of the lithium ion conductive layer 14 in the case of the lithium-sulfur solid battery 10 shown in FIG. 1) is not particularly limited.
The thickness of the lithium ion conductive layer composed of a plurality of layers means the total thickness of all the layers constituting the lithium ion conductive layer.

  However, the thickness of the lithium ion conductive layer is preferably 10 μm or more in that the effect of suppressing the deposition of metallic lithium in the solid electrolyte becomes higher. If the thickness of the lithium ion conductive layer is equal to or more than the lower limit, no metal lithium is precipitated in the lithium ion conductive layer, or even if a small amount of metal lithium is precipitated in the lithium ion conductive layer, The effect does not reach the solid electrolyte. As a result, in the lithium-sulfur solid battery, continuous deposition of metallic lithium between the lithium ion conductive layer and the sulfur positive electrode through the solid electrolyte is suppressed.

On the other hand, the lithium ion conductive layer preferably has a thickness of 100 μm or less from the viewpoint that the thickness of the lithium ion conductive layer does not become excessive (more appropriate).
Usually, as the lithium ion conductive layer becomes thinner, the resistance value in the lithium ion conductive layer decreases, and the energy density of the lithium sulfur solid battery increases.

  The lithium ion conductive layer is prepared, for example, by preparing a first raw material composition containing the constituent material of the main body, an ionic liquid, and a solvent as necessary. It can be formed by applying the first raw material composition and drying it as necessary. This method is a method in which the main body and the lithium ion conductive layer are formed simultaneously. When no solvent is used, it is not necessary to dry the coated first raw material composition.

  At the time of preparing the first raw material composition, the temperature and time during the addition and mixing of each raw material are not particularly limited as long as each raw material does not deteriorate. For example, although the temperature at the time of mixing may be 15-50 degreeC, this is an example. The method of mixing each raw material may be the same as the method of mixing each component at the time of manufacturing the above-described positive electrode material, for example.

The first raw material composition can be applied to the surface on which the lithium ion conductive layer is to be formed by a known method.
The temperature of the 1st raw material composition to apply is not specifically limited unless the formation object surface of a lithium ion conductive layer, the constituent material of a main-body part, an ionic liquid, a solvent, etc. deteriorate. For example, although the temperature of the 1st raw material composition at this time may be 15-50 degreeC, this is an example.

  When the first raw material composition is dried, the drying can be performed by a known method under normal pressure or reduced pressure. The drying temperature of a 1st raw material composition is not specifically limited, For example, although 20-100 degreeC may be sufficient, this is an example.

When the formation target surface of the lithium ion conductive layer is an arrangement surface of the lithium ion conductive layer in the lithium-sulfur solid battery (for example, the surface on the lithium negative electrode side of the solid electrolyte, the surface on the solid electrolyte side of the lithium negative electrode, etc.) In this case, the formed lithium ion conductive layer does not need to be moved to another location, and may be arranged as it is.
On the other hand, when the formation target surface of the lithium ion conductive layer is not the arrangement surface of the lithium ion conductive layer in the lithium sulfur solid battery, the formed lithium ion conductive layer is peeled off from this surface, and the lithium sulfur solid battery What is necessary is just to move by sticking to the target arrangement surface in the inside.

In addition, the lithium ion conductive layer is, for example, impregnated with ionic liquid in the main body, or prepared a mixed liquid containing an ionic liquid and a solvent, and impregnated with the mixed liquid in the main body. It can be formed by drying the main body after impregnation if necessary. This method uses a pre-formed main body. When no solvent is used, it is not necessary to dry the main body after impregnation.
In this case, the main body portion is not arranged on the arrangement surface of the lithium ion conductive layer in the lithium-sulfur solid battery, but is handled independently, and after the lithium ion conductive layer is formed, the obtained lithium ion It is preferable that the conductive layer is further bonded to a target arrangement surface in the lithium-sulfur solid battery.

The main body can be produced by a known method, for example, by preparing a second raw material composition containing the constituent material of the main body and molding the second raw material composition.
Moreover, a commercial item may be sufficient as the said main-body part.

  As a method for impregnating the main body with the ionic liquid or mixed liquid, for example, a method of coating the main body with the ionic liquid or mixed liquid, or immersing the main body in the ionic liquid or mixed liquid Methods and the like.

The ionic liquid or mixed liquid can be applied to the main body by a known method.
The temperature of the ionic liquid or mixed liquid impregnated in the main body is not particularly limited as long as the raw materials such as the main body, the ionic liquid, and the solvent are not deteriorated. For example, the temperature of the ionic liquid or mixed liquid at the time of impregnation may be 15 to 50 ° C., but this is an example.

  Drying of the main body after impregnation with the mixed liquid can be performed by a known method under normal pressure or reduced pressure. The drying temperature at this time is not specifically limited, For example, 20-100 degreeC may be sufficient, but this is an example.

  The lithium-sulfur solid state battery of the present embodiment is not limited to the above-described one, and a part of the configuration described above has been changed, deleted, or added within the scope not departing from the gist of the present invention. It may be.

For example, the lithium-sulfur solid battery of the present embodiment includes one or more other layers that do not correspond to any of a sulfur positive electrode, a solid electrolyte, a lithium ion conductive layer, and a lithium negative electrode. Alternatively, two or more layers may be provided.
The other layers are not particularly limited as long as the effects of the present invention are not impaired, and can be arbitrarily selected according to the purpose.

  For example, a separator for stabilizing the amount of lithium ions transferred from the solid electrolyte 13 to the sulfur positive electrode 11 may be provided between the sulfur positive electrode 11 and the solid electrolyte 13.

In the configuration in which the other layer is provided, in a lithium-sulfur solid battery in which a gold sputter layer is disposed between the sulfur positive electrode and the solid electrolyte and these three layers are in direct contact with each other in this order, Therefore, the interface resistance value at the sulfur positive electrode interface is reduced as compared with the case where no sputter layer is disposed. For example, when the sulfur positive electrode is a known one having a positive electrode active material layer on a current collector (positive electrode current collector), such an effect of reducing the interface resistance value is more prominent. Become.
In this case, the thickness of the gold sputter layer is preferably 50 nm or more, and more preferably 100 to 200 nm.

  However, in the case of using a sulfur positive electrode configured to contain a component such as sulfur in the gap portion of the conductive sheet having a large number of void portions, in the lithium-sulfur solid battery of the present embodiment, a sulfur positive electrode, It is preferable that the solid electrolyte, the lithium ion conductive layer, and the lithium negative electrode are in direct contact with each other in this order (the other layers are not provided).

As shown in FIG. 1, the holding member 15 collectively holds the sulfur positive electrode 11, the solid electrolyte 13, the lithium ion conductive layer 14, and the lithium negative electrode 12, and increases the separation distance between the sulfur positive electrode 11 and the lithium negative electrode 12. It is a member that regulates.
The holding member 15 shown in FIG. 1 includes an outer peripheral portion of a laminate 16 (a sheet-like laminate, also referred to as a laminate sheet hereinafter) of a sulfur positive electrode 11, a solid electrolyte 13, a lithium ion conductive layer 14, and a lithium negative electrode 12. A laminated body fitting groove 15a is formed in which is fitted. The holding member 15 holds the laminated body sheet 16 inserted and fitted into the laminated body fitting groove 15 a and regulates an increase in the separation distance between the sulfur positive electrode 11 and the lithium negative electrode 12.

As the holding member 15, a member made of a material such as rubber or synthetic resin having electrical insulation and liquid shielding properties can be suitably used.
The holding member 15 having liquid shielding properties also serves as a sealing material that prevents leakage of the ionic liquid from the outer peripheral end of the laminate sheet 16 by being fitted to the laminate sheet 16.

<< Production Method of Lithium Sulfur Solid Battery >>
In the lithium-sulfur solid battery of the present embodiment, the solid electrolyte is positioned between the sulfur positive electrode and the lithium negative electrode, and the lithium ion conductive layer is positioned between the solid electrolyte and the lithium negative electrode. The sulfur positive electrode, the lithium negative electrode, the solid electrolyte, and the lithium ion conductive layer can be manufactured by a method having a step.
In other words, the lithium-sulfur solid battery of this embodiment can be manufactured by a method including a step of laminating the sulfur positive electrode, the solid electrolyte, the lithium ion conductive layer, and the lithium negative electrode in this order in the thickness direction.
For example, the lithium-sulfur solid battery of the present embodiment is a known one except that a lithium ion conductive layer is newly used and a sulfur positive electrode, a solid electrolyte, a lithium ion conductive layer, and a lithium negative electrode are stacked so as to have the above-described arrangement. It can be manufactured by the same method as in the case of a lithium-sulfur solid battery. In the case of using a thing equipped with the above-mentioned electroconductive sheet as a sulfur positive electrode, in addition to the conventional sulfur positive electrode, in addition to using such a sulfur positive electrode, in the case of a known lithium-sulfur solid battery Can be manufactured in the same way.

  The handling temperature of the lithium-sulfur solid battery of the present embodiment is preferably 110 ° C. or lower, and more preferably 100 ° C. or lower. By doing in this way, vaporization of an ionic liquid can be suppressed and leakage of sulfur can be suppressed, and the lithium-sulfur solid battery exhibits more excellent battery characteristics.

  The lithium-sulfur solid battery of this embodiment has excellent battery characteristics as described above, and has high safety. The lithium-sulfur solid state battery is suitable for use as, for example, a household power source; an emergency power source;

Since the lithium-sulfur solid battery 10 (specifically, the laminate sheet 16) has flexibility, it can be wound in a cylindrical shape as shown in FIGS. 2 and 3, for example.
2 and 3 show a cylindrical battery 17 formed by a lithium-sulfur solid battery 10 wound in a cylindrical shape.

  The cylindrical battery 17 shown in FIGS. 2 and 3 is a lithium-sulfur solid battery 10 wound in a direction facing the outer periphery of the sulfur positive electrode 11 and facing the inner periphery of the lithium negative electrode 12. As shown in FIGS. 3 and 4, portions of the lithium sulfur solid battery 10 constituting the cylindrical battery 17 that are adjacent to each other in the radial direction of the cylindrical cylindrical battery 17 are in contact with each other. For this reason, in the cylindrical battery 17, the sulfur positive electrode 11 and the lithium negative electrode 12 of the lithium-sulfur solid battery 10 are in contact with each other over a wide range. As a result, in the cylindrical battery 17, the energy density can be easily improved as compared with the case where the lithium-sulfur solid battery 10 is used in a flat plate state.

  In addition, the cylindrical battery 17 can also employ a configuration in which the lithium-sulfur solid battery 10 is wound so that the sulfur positive electrode 11 faces the inner peripheral side and the lithium negative electrode 12 faces the outer peripheral side.

FIG. 2 is also a diagram illustrating an example of a battery 18 with a current collector configured using the cylindrical battery 17.
A battery-equipped battery 18 in FIG. 2 includes a cylindrical battery 17, an inner current collector 18a that is inserted into the hollow portion 17a inside the cylindrical battery 17 and is in contact with the inner peripheral surface of the hollow portion 17a, and the cylindrical battery. 17 and a cylindrical outer current collector 18 b that is in contact with the side peripheral surface of the cylindrical battery 17.
Examples of the material of the inner current collector 18a and the outer current collector 18b include carbon, copper, aluminum, titanium, nickel, and stainless steel. The inner current collector 18a is formed in a rod shape.
The inner current collector 18a and the outer current collector 18b function as a positive electrode current collector in contact with the sulfur positive electrode 11 and function as a negative electrode current collector in contact with the lithium negative electrode 12.

The inner current collector 18a may be a solid rod shape or a hollow rod shape (tubular shape).
The outer current collector 18b only needs to be able to contact and abut on the side peripheral surface of the cylindrical battery 17, and is not limited to a cylindrical one that accommodates the cylindrical battery 17, and adopts various configurations. Is possible.

FIG. 5 shows a sheet-shaped solid electrolyte 13 (hereinafter also referred to as an electrolyte sheet) having a thickness of 10 to 500 μm, a flexible sheet-shaped sulfur positive electrode 11 (hereinafter also referred to as a sulfur positive electrode sheet), a sulfur positive electrode sheet 11 and The battery positive electrode sheet 20 comprised by the holding member (illustration omitted) which hold | maintains the outer peripheral part of the electrolyte sheet 13, and maintains the overlapping state of the sulfur positive electrode sheet 11 and the electrolyte sheet 13 is shown.
The same thing as what was demonstrated in the above-mentioned lithium sulfur solid battery 10 can be used for the sulfur positive electrode sheet 11 and the electrolyte sheet 13.
The battery positive electrode sheet 20 has flexibility.

FIG. 6 shows the lithium ion conductive layer 14 sandwiched between the electrolyte sheet 13 and a flexible sheet-like lithium negative electrode 12 (hereinafter also referred to as a negative electrode sheet), and holds the outer periphery of the electrolyte sheet 13 and the negative electrode sheet 12. Then, a battery negative electrode sheet 30 having a configuration in which a holding member (not shown) that maintains a state in which the lithium ion conductive layer 14 is sandwiched between the electrolyte sheet 13 and the flexible sheet-like negative electrode sheet 12 is provided is shown.
The negative electrode sheet 12, the electrolyte sheet 13, and the lithium ion conductive layer 14 can be the same as those described in the above-described lithium-sulfur solid battery 10.
The negative electrode sheet 30 for batteries has flexibility.

  The lithium sulfur solid battery 10, the battery positive electrode sheet 20, and the battery negative electrode sheet 30 can be used for assembling a laminated battery by laminating two or more selected from these.

DESCRIPTION OF SYMBOLS 10 ... Lithium sulfur solid battery, 11 ... Sulfur positive electrode, 12 ... Lithium negative electrode, 13 ... Solid electrolyte, 14 ... Lithium ion conductive layer, 15 ... Holding member, 16 ... Laminate sheet, 17 ... Cylindrical battery, 18 ... Current collection Battery with body, 18a ... inner current collector, 18b ... outer current collector, 20 ... positive electrode sheet for battery, 30 ... negative electrode sheet for battery.

Claims (9)

A solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, a sulfur positive electrode formed in a sheet shape and having flexibility, a lithium negative electrode formed in a sheet shape and having flexibility, the solid electrolyte, and the lithium negative electrode A lithium ion conductive layer disposed between the lithium positive electrode and the lithium positive electrode disposed on the opposite side of the lithium ion conductive layer with the fixed electrolyte held between the lithium positive electrode and the lithium negative electrode. A holding member that regulates an increase in the distance between the negative electrode,
The sulfur positive electrode is formed of a conductive material and has a conductive sheet having a large number of holes opened on the surface, and sulfur, a conductive auxiliary agent, a binder and an ionic liquid, only sulfur and ionic liquid or sulfur, a conductive auxiliary agent, Containing all of a binder and ionic liquid, and having a positive electrode material accommodated in the hole of the conductive sheet,
The lithium ion conductive layer is impregnated with an ionic liquid in a flexible sheet-like main body that is a porous body or a fiber assembly, and conducts lithium ions between the lithium negative electrode and the solid electrolyte. Lithium sulfur solid battery. A flexible battery positive electrode sheet having a sulfur positive electrode,
A solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, and the sulfur positive electrode formed in a sheet shape and having flexibility,
The sulfur positive electrode is formed of a conductive material and has a conductive sheet having a large number of holes opened on the surface, and sulfur, a conductive auxiliary agent, a binder and an ionic liquid, only sulfur and ionic liquid or sulfur, a conductive auxiliary agent, A positive electrode sheet for a battery having flexibility, comprising a binder and a positive electrode material that contains all of an ionic liquid and is accommodated in the hole of the conductive sheet. A flexible negative electrode sheet for a battery having a lithium negative electrode,
A solid electrolyte formed in a sheet shape having a thickness of 10 to 500 μm, a lithium negative electrode formed in a sheet shape and having flexibility, and a lithium ion conductive layer disposed between the solid electrolyte and the lithium negative electrode. Prepared,
The lithium ion conductive layer is impregnated with an ionic liquid in a flexible sheet-like main body that is a porous body or a fiber assembly, and conducts lithium ions between the lithium negative electrode and the solid electrolyte. A battery negative electrode sheet having flexibility.   The lithium-sulfur solid battery according to claim 1 is formed by being wound in a cylindrical shape, and the lithium-sulfur solid battery is wound in a direction in which one of the sulfur positive electrode and the lithium negative electrode is an inner peripheral side and the other is an outer peripheral side. A cylindrical battery in which the adjacent portions in the radial direction of the cylindrical lithium-sulfur solid battery are in contact with each other.   A cylindrical battery according to claim 4, and a metal rod-like shape which is inserted into a hollow portion inside the cylindrical battery and is in contact with the sulfur positive electrode or the lithium negative electrode forming the inner peripheral surface of the cylindrical battery. A cylindrical battery with a current collector, comprising: an inner current collector; and a metal outer current collector that is in contact with the sulfur positive electrode or the lithium negative electrode forming a side peripheral surface of the cylindrical battery.   The laminated battery comprised by laminating | stacking 2 or more selected from the lithium sulfur solid battery of Claim 1, the positive electrode sheet for batteries of Claim 2, and the negative electrode sheet for batteries of Claim 3.   The lithium sulfur solid battery according to claim 1, wherein the solid electrolyte is formed of an oxide-based material.   The battery positive electrode sheet according to claim 2, wherein the solid electrolyte is formed of an oxide-based material.   The negative electrode sheet for batteries according to claim 3, wherein the solid electrolyte is formed of an oxide-based material.

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