ELECTRODE FOR SOLID-BODY BATTERY AND SOLID-BODY BATTERY

Abstract

An electrode for a solid-state battery comprises a sulfide solid electrolyte and a metal that reacts with the sulfide solid electrolyte to exhibit electronic conductivity. The metal content, based on the total volume of the electrode for a solid-state battery, is greater than or equal to 5 ppm by volume and less than 10,000 ppm by volume.

Description

BACKGROUND Technical area

[0001] The present invention relates to an electrode for a solid-state battery, and a solid-state battery. State of the art

[0002] In light of the rapid proliferation of information-related devices, communication devices, and the like, such as personal computers, video cameras, and mobile phones in recent years, the development of batteries used as their energy sources is considered crucial. The primary focus is on lithium-ion batteries, as these offer high energy density and excellent stability.

[0003] Conventional batteries used in the aforementioned applications employ electrolyte liquids containing flammable organic solvents. Therefore, improved structures and materials are necessary to prevent short circuits and to incorporate safety devices that suppress temperature rises during a short circuit. For this reason, batteries are currently being developed in which the electrolyte solution is replaced by a layer of solid electrolyte. By using a solid electrolyte instead of a solution, thus transforming the battery into a solid-state battery, no flammable organic solvents are used, safety devices can be simplified, and manufacturing costs and production efficiency are improved.

[0004] Normally, in a case where the positive and negative electrode layers of a solid-state battery contain a metal such as copper, the metal is removed because of the risk of a short circuit.

[0005] For example, in Japanese patent application JP 2020 191 183 A, a solid-state battery with a positive electrode layer, a sulfide solid electrolyte layer and a negative electrode layer is aged before the first charging, and the metal such as copper is removed by melting. SUMMARY

[0006] Solid-state batteries tend to increase in resistance through repeated charge and discharge cycles. This increase in resistance means that the battery deteriorates due to repeated charging and discharging.

[0007] The present inventors have discovered that the above-described increase in resistance can be contained by including a specific metal with a specific content in the positive electrode layer or the negative electrode layer.

[0008] An embodiment according to the present invention was made in view of the circumstances described above and is directed towards providing an electrode for a solid-state battery and a solid-state battery in which an increase in the resistance of a solid-state battery can be reduced.

[0009] The aspects according to the present invention for providing such an electrode and a solid-state battery include the following aspects.

[0010] <1> An electrode for a solid-state battery, comprising: a sulfide solid electrolyte; and a metal that reacts with the sulfide solid electrolyte to exhibit electronic conductivity, wherein the metal content, based on the total volume of the electrode for a solid-state battery, is greater than or equal to 5 ppm based on volume or 5 vol. ppm and less than 10,000 ppm based on volume or 10,000 vol. ppm.

[0011] <2> The electrode for a solid-state battery according to <1> , wherein the metal is at least a metal selected from the group consisting of copper, silver, nickel, iron, tin, aluminium, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum and alloys thereof.

[0012] <3> The electrode for a solid-state battery according to <2> , where the metal is at least one of copper or silver.

[0013] <4> The electrode for a solid-state battery after one of the points <1> until <3> , wherein the metal content, based on the total volume of the electrode for a solid-state battery, is greater than or equal to 50 ppm based on volume.

[0014] <5> The electrode for a solid-state battery after one of the points <1> until <4> , wherein the metal content, based on the total volume of the electrode for a solid-state battery, is less than or equal to 5,000 ppm by volume.

[0015] <6> The electrode for a solid-state battery after one of the points <1> until <5> , wherein the sulfide solid electrolyte contains a phosphorus atom.

[0016] <7> A solid-state battery comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. wherein at least one of the positive electrode layer or the negative electrode layer is the electrode for a solid-state battery according to one of the points <1> until <6> is.

[0017] According to one embodiment of the present invention, an electrode can be provided for a solid-state battery, in which an increase in the resistance of a solid-state battery can be reduced. SHORT DESCRIPTION OF THE DRAWING Fig. Figure 1 is a schematic cross-sectional view showing an embodiment of a solid electrolyte according to the present invention. DETAILED DESCRIPTION

[0018] In the present invention, each numerical range expressed by “to” means a range comprising numerical values ​​described before and after “to” as the lower limit and upper limit.

[0019] In numerical ranges that are described stepwise in the present invention, the upper limit or the lower limit of one numerical range can be replaced by the upper limit or the lower limit of another numerical range in the stepwise description. The upper limit or the lower limit of any numerical range described in the present disclosure can also be replaced by a value described in an example.

[0020] In the present disclosure, a combination of two or more advantageous aspects constitutes a more advantageous aspect.

[0021] If several substances are present that correspond to a component of interest, the quantity of the component described in this specification means the total quantity of the several substances, unless otherwise stated.

[0022] In the present invention, ‘solid electrolyte’ means an electrolyte which maintains a solid state at 25 °C in a nitrogen atmosphere.

[0023] In the present invention, the term ‘sulfide solid electrolyte’ includes both crystalline sulfide solid electrolytes with a crystal structure and amorphous sulfide solid electrolytes.

[0024] In the present disclosure, a crystalline sulfide solid electrolyte is a solid electrolyte whose X-ray diffraction pattern obtained by powder X-ray diffraction (XRD) exhibits a peak derived from the solid electrolyte, regardless of whether a peak derived from the raw material of the solid electrolyte is present in the X-ray diffraction pattern. A crystalline sulfide solid electrolyte is a sulfide solid electrolyte comprising a crystal structure derived from the solid electrolyte, wherein a portion of the sulfide solid electrolyte or the entire sulfide solid electrolyte may be the crystal structure derived from the solid electrolyte. Furthermore, the crystalline sulfide solid electrolyte may contain an amorphous sulfide solid electrolyte (also called the "glass component") in a portion, as long as the crystalline sulfide solid electrolyte exhibits an X-ray diffraction pattern as described above.Accordingly, the range of crystalline sulfide solid electrolytes includes a so-called glass ceramic, which is obtained by heating an amorphous solid electrolyte (a glass component) to its crystallization temperature or higher.

[0025] Furthermore, in the present invention, the amorphous sulfide solid electrolyte (glass component) is a sulfide solid electrolyte whose X-ray diffraction pattern obtained by powder X-ray diffraction (XRD) measurement exhibits a halo pattern in which essentially no peaks other than those originating from the material are observed, regardless of whether or not peaks originating from the raw materials of the solid electrolyte are present. [Electrode for solid-state battery]

[0026] The electrode for a solid-state battery according to the present invention comprises a sulfide solid-state electrolyte and a metal that reacts with the sulfide solid-state electrolyte to exhibit electronic conductivity (hereinafter also referred to as the “specific metal”).

[0027] The metal content in relation to the total volume of the electrode for a solid-state battery is greater than or equal to 5 ppm by volume and less than 10,000 ppm by volume.

[0028] In accordance with the electrode for a solid-state battery according to the present invention, the increase in resistance of a solid-state battery can be reduced. Although the reason for this effect is not clear, it is assumed to be as follows.

[0029] Since the electrode for a solid-state battery according to the present invention contains a sulfide solid electrolyte and more than or equal to 5 ppm by volume of the specific metal, the sulfide solid electrolyte and the specific metal react during the generation of heat during charging and discharging to form a metal sulfide or a metal thiophosphate. We hypothesize that the excellent electronic conductivity of these generated substances improves the efficiency of the electronic conduction path and limits the increase in resistance. Furthermore, we hypothesize that the reaction between the sulfide solid electrolyte and the specific metal imparts electronic conductivity to the sulfide solid electrolyte and reduces the increase in resistance.

[0030] Furthermore, we suspect that adjusting the content of the specific metal in the electrode for a solid-state battery according to the present invention to less than 10,000 ppm by volume will enable a containment of the reduction in ionic conductivity and a containment of the increase in resistance.

[0031] The reduction of the increase in resistance of a solid-state battery can also be evaluated based on the resistance of the solid-state battery after heat treatment, as shown in the examples described later. (sulfide solid electrolyte)

[0032] The sulfide solid electrolyte can contain a lithium atom, a sulfur atom, and a halogen atom.

[0033] To induce a reaction between the sulfide solid electrolyte and the specific metal, and especially to limit an increase in resistance, the sulfide solid electrolyte preferably contains a phosphorus atom. Since the sulfide solid electrolyte includes a phosphorus atom, a metal thiophosphate is formed that exhibits both ionic and electronic conductivity.

[0034] The sulfide solid electrolyte can be amorphous or crystalline.

[0035] In one embodiment, the composition of the sulfide solid electrolyte is represented, for example, by xLi2S·(100-x)P2S5 (70≤x≤80) or yLiI·zLiBr·(100-yz)(xLi2S·(1-x)P2S5) (0,7≤x≤0,8, 0≤y≤30, 0≤z≤30).

[0036] Furthermore, the sulfide solid electrolyte can have the composition represented by the following formula (1). Li 4-x Ge 1-x P x S4 (0 <x<1) ... Formel (1)

[0037] In formula (1), at least one part of Ge can be replaced by at least one element from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. Furthermore, at least one part of P can be replaced by at least one element from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. One part of Li can be replaced by at least one element from the group consisting of Na, K, mg, Ca, and Zn. One part of S can be replaced by a halogen, where the halogen can be at least one of the elements F, Cl, Br, or I.

[0038] Examples of amorphous sulfidic solid electrolytes include: solid electrolytes composed of lithium sulfide, phosphorus sulfide, and lithium halides, such as Li2S-P2S5-Lil, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, and Li2S-P2S5-Lil-LiBr; solid electrolytes containing an additional atom, such as an oxygen atom or a silicon atom, such as Li2S-P2S5-Li2O-Lil and Li2S-SiS2-P2S5-Lil.

[0039] From the point of view of obtaining an even higher ionic conductivity, preferred examples include solid electrolytes composed of lithium sulfide, phosphorus sulfide and lithium halides such as Li2S-P2S5-Lil, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr and Li2S-P2S5-Lil-LiBr.

[0040] The type of atoms that structure the amorphous sulfide solid electrolyte can be confirmed, for example, using an ICP emission spectrophotometer.

[0041] The crystalline sulfide solid electrolyte can be a so-called glass-ceramic, which is obtained by heating an amorphous solid electrolyte to its crystallization temperature or higher. Examples of its crystal structure include the Li3PS4 crystal structure, the Li4P2S6 crystal structure, the Li7PS6 crystal structure, and the Li7P3S 11-Crystal structure and crystal structures with peaks near 2θ = 20.2° and near 23.6° (see, e.g., JP 2013-16 423 A). Further examples include Li-type crystal structures. 4-x Ge 1-x P x S4 thio-LISICON Region II (see Kanno et al., Journal of The Electrochemical Society, 148(7) A742-746 (2001)), and crystal structures (see Solid State onics, 177(2006), 2721-2725), which correspond to the Li-type crystal structures 4-x Ge 1-x P x S4 thio-LISICON Region II are similar.

[0042] The shape of the sulfide solid electrolyte is not particularly restricted, and the sulfide solid electrolyte is, for example, particulate. The mean particle diameter (D 50 ) of the particulate sulfide solid electrolyte, for example, lies in a range of 0.01 µm to 500 µm or from 0.1 to 200 µm.

[0043] The proportion of the sulfide solid electrolyte to the total mass of the electrode for a solid-state battery is preferably between 2% and 90% by mass, and even more preferably between 5% and 30% by mass.

[0044] Furthermore, the content (volume fraction) of the sulfide solid electrolyte in relation to the total volume of the electrode for a solid-state battery is preferably 3 to 95 vol%, and even more preferably 4 to 85 vol%. (Specific metal)

[0045] The electrode for a solid-state battery according to the present invention contains a metal that reacts with a sulfide solid electrolyte to exhibit electronic conductivity (i.e., the specific metal). Examples of the specific metal include at least one metal from the group consisting of copper, silver, nickel, iron, tin, aluminum, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum, and their alloys. From the point of view of an even lower increase in resistance, at least one of the metals, copper or silver, is preferred, with copper being even more preferred.

[0046] The shape of the metal is not particularly restricted, and the metal can be particle-shaped or non-particle-shaped.

[0047] This section describes a method for verifying whether a metal is a metal that reacts with a sulfide solid electrolyte and exhibits electronic conductivity (i.e., is the specific metal). First, the metal under investigation and a sulfide solid electrolyte are mixed and heat-treated to obtain a sample. The mixing and heat-treatment conditions described below are applied.

[0048] Mixing conditions: A sulfide solid electrolyte and the metal to be tested (a metal powder is used for this purpose) are mixed together so that the volume concentration of the metal powder is 5%. 1 g of the sulfide solid electrolyte and the metal powder in an amount providing a volume concentration of 5% are weighed out and dry-mixed in a mortar for 5 minutes to obtain a mixed powder.

[0049] Heat treatment conditions: The Swagelok cell described below is placed in a thermostatic container set to 150 °C and heat-treated for seven days. After seven days, the Swagelok cell is removed from the thermostatic container. Once the Swagelok cell has cooled to 25 °C, the post-heat-treatment electron conductance is measured.

[0050] The electronic conductivity of the obtained sample is measured before heat treatment and after heat treatment using the following procedure.

[0051] 200 mg of the sample are weighed out, placed in a cylinder manufactured by Swagelok, and subjected to a pressure of 1 ton / cm². 2The pellet is pressed. The two ends are clamped with SUS pins, and the tightening of the bolts applies holding pressure to the pellet. This structure, in which the pellet is enclosed by the cylinder manufactured by Swagelok, is called a Swagelok cell. To obtain the sample after heat treatment, this Swagelok cell is subjected to heat treatment under the heat treatment conditions described above. The electronic conductivity is determined by the DC polarization method while the sample is kept at 25 °C. The CELTEST and SOLARTRON 1260 instruments from Solartron are used for the measurement. A voltage of 0.1 V, 0.2 V, or 0.3 V is applied for 30 seconds, and the current flowing at each voltage is measured.The resistance is calculated from the ratio between the applied voltage and the flowing current, and the electron conductance is then determined from this.

[0052] The electron conductivities before and after heat treatment are then compared. The rate of increase in electron conductivity is calculated by dividing the electron conductivity after heat treatment by the electron conductivity before heat treatment. If the rate of increase in electron conductivity is greater than or equal to 2.17, the metal is assumed to be one that reacts with the sulfide solid electrolyte and exhibits electron conductivity (i.e., it is the specific metal).

[0053] If the specific metal is particulate, a smaller particle diameter is preferable, as the reactivity with the sulfide solid electrolyte increases, thereby achieving a greater effect.

[0054] From the perspective of containing the sulfide solid electrolyte and allowing the specific metal to react, and further reducing any increase in resistance, the content of the specific metal in relation to the total volume of the electrode for a solid-state battery is preferably greater than or equal to 20 ppm by volume, and is more preferably greater than or equal to 100 ppm by volume, and is even more preferably greater than or equal to 200 ppm by volume, and is particularly preferably greater than or equal to 450 ppm by volume, and is most preferably greater than or equal to 600 ppm by volume, and can be greater than or equal to 1,000 ppm by volume.

[0055] With a view to further reducing the decrease in ionic conductivity and the increase in resistance, the content of the specific metal, based on the total volume of the electrode for a solid-state battery, is preferably less than or equal to 8,000 ppm by volume, and is more preferably less than or equal to 7,000 ppm by volume, and is even more preferably less than or equal to 6,000 ppm by volume, and is particularly preferably less than or equal to 5,500 ppm by volume, and can be less than or equal to 5,000 ppm by volume.

[0056] Furthermore, the content of the specific metal in relation to the total volume of the electrode for a solid-state battery, from the point of view of reducing self-discharge and reducing short circuits, is preferably less than or equal to 4,000 ppm by volume and more preferably less than or equal to 3,000 ppm by volume.

[0057] In the present invention, the content (volume fraction) of the specific metal in the electrode for a solid-state battery can be measured according to the following method.

[0058] A cross-section of the electrode for a solid-state battery is viewed using a scanning electron microscope with EDS (SEM-EDS, magnification 30,000X), and the content (volume fraction) of the specific metal can be measured by performing an elemental analysis using energy-dispersive spectroscopy (EDS). (Active material)

[0059] The electrode for a solid-state battery according to the present invention can contain an active material. The active material can be an active material of or for the positive electrode, or it can be an active material of or for the negative electrode.

[0060] The electrode for a solid-state battery according to the present invention preferably comprises a lithium compound oxide as the active material of the positive electrode. The lithium compound oxide can comprise at least one element selected from the group consisting of F, Cl, N, S, Br, and I. Furthermore, the lithium compound oxide can have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc (also called P63mc, P6 / mmc). In the lithium compound oxide, the major sequence of transition metal, oxygen, and lithium can be an O2-type structure.

[0061] Examples of lithium compound oxides with a crystal structure belonging to R-3m include compounds formed by Li x Me y O α X β represented (where Me represents at least one element selected from the group consisting of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, mg, Pt, Au, Ag, Ru, W, B, Si and P, and X represents at least one selected from the group consisting of F, Cl, N, S, Br and I, and x, y, α and β satisfy 0.5≤x≤1.5, 0.5≤y≤1.0, 1≤α<2, and 0<β≤1).

[0062] Examples of lithium compound oxides with a crystal structure belonging to Immm include compound oxides formed by Li x1 M 1 A 1 2 are represented (where x1 satisfies the conditions 1.5≤x1≤2.3). M 1 includes at least one element selected from the group consisting of Ni, Co, Mn, Cu and Fe, A 1includes at least oxygen, and the proportion of oxygen in the entire A 1 is greater than or equal to 85 atomic % (a specific example of this is Li2NiO2), and compound oxides represented by Li x1 M 1A 1-x2 M 1B x2 O 2-y A 2 y (in which x20≤x2≤0.5 is satisfied, y0≤y≤0.3 is satisfied, at least one of x2 or y is not 0, M 1A M1B represents at least one element selected from the group consisting of Ni, Co, Mn, Cu and Fe, M1B represents at least one element selected from the group consisting of Al, Mg, Sc, Ti, Cr, V, Zn, Ga, Zr, Mo, Nb, Ta and W, and A 2 at least one element selected from the group consisting of F, Cl, Br, S and P).

[0063] Examples of lithium compound oxides with a crystal structure belonging to P63-mmc include compound oxides characterized by M1 x M2 yO2 are represented (where M1 is an alkali metal (preferably at least one of Na or K), M2 is a transition metal (preferably at least one selected from the group consisting of Mn, Ni, Co and Fe), and x+y is the condition 0 <x+y≤2 erfüllt).

[0064] Examples of lithium compound oxides with an O2-type structure include compound oxides formed by Li x [Li a (Mn a Co b M c ) 1-a ]O2 can be represented (x satisfies 0.5 <x<1,1, α erfüllt 0,1<α<0,33, a erfüllt 0,17<a<0,93, b erfüllt 0,03<b<0,50, C erfüllt 0,04<c<0,33, und M stellt mindestens ein Element dar, das aus der Gruppe ausgewählt ist, die aus Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W und Bi besteht). Spezifische Beispiele umfassen Li 0,744 [Li 0,145 Mn 0,625 Co 0,115 Ni 0,115 ]O2.

[0065] Examples of active materials for the negative electrode include silicon, silicon alloys, and silicon oxides. Other examples of active materials for the negative electrode that can be used include metallic lithium and metals that can form alloys with metallic lithium, such as metallic lithium, metallic indium, metallic aluminum, metallic silicon, and metallic tin, as well as oxides of these metals and alloys of these metals with metallic lithium. Examples of oxides include active oxide materials such as Li₄Ti₅O₂. 12 Examples of active materials for the negative electrode also include carbon. Examples of carbon include natural graphite, synthetic graphite, hard carbon (non-graphitized carbon), and soft carbon (lightly graphitized carbon). Examples of synthetic graphite include highly oriented graphite and mesocarbon microbeads.

[0066] The active material content in the positive electrode of a solid-state battery according to the present invention is preferably 20% to 99% by mass, and more preferably 50% to 90% by mass, based on the total mass of the positive electrode. The active material content in the negative electrode of a solid-state battery according to the present disclosure is preferably 20% to 99% by mass, and more preferably 50% to 90% by mass, based on the total mass of the negative electrode. However, with respect to the negative electrode, the active material content can be 100% by mass if a lithium metal or the like is used.

[0067] Furthermore, the content (volume fraction) of the active material in the positive electrode is preferably 10 to 99 vol.%, and even more preferably 32 to 81 vol.%. The content (volume fraction) of the active material in the negative electrode is preferably 10 to 99 vol.%, and even more preferably 32 to 81 vol.%, based on the total volume of the negative electrode. (Conductive aid)

[0068] The electrode for a solid-state battery according to the present invention may contain a conductive auxiliary.

[0069] Examples of conductive auxiliary materials include carbon-based materials such as synthetic graphite, graphite-carbon fibers, resin-baked carbon, thermally decomposed vapor-deposited carbon, coke, mesocarbon microbeads, resin-baked furfuryl alcohol carbon, polyacenes, pitch-based carbon fibers, vapor-deposited carbon fibers, natural graphite, and non-graphitizing carbon.

[0070] The content of the conductive additive in the positive electrode of the electrode for a solid-state battery according to the present invention is preferably between 0% and 20% by mass, and more preferably between 0% and 3% by mass, based on the total mass of the positive electrode. The content of the conductive additive in the negative electrode of the electrode for a solid-state battery according to the present disclosure is preferably between 0% and 20% by mass, and more preferably between 0% and 3% by mass, based on the total mass of the negative electrode.

[0071] Furthermore, the content (volume fraction) of the conductive additive in the positive electrode is preferably 0 to 45 vol.%, and more preferably 0 to 5.5 vol.%, based on the total volume of the positive electrode. The content (volume fraction) of the conductive additive in the negative electrode is preferably 0 to 45 vol.%, and particularly preferably 0 to 5.5 vol.%, based on the total volume of the negative electrode. (Binder)

[0072] The electrode for a solid-state battery according to the present invention may contain a binder.

[0073] Examples of the binder include fluorine-based polymers such as polytetrafluoroethylene and polyvinylidene fluoride, thermoplastic elastomers such as butylene rubber and styrene-butadiene rubber, and various resins such as acrylic resins, acrylic polyol resins, polyvinyl acetal resins, polyvinyl butyral resins, and silicone resins.

[0074] The binder content in the positive electrode of a solid-state battery according to the present invention is preferably 0% to 10% by mass, and even more preferably 0% to 3% by mass, based on the total mass of the positive electrode. The binder content in the negative electrode of a solid-state battery according to the present disclosure is preferably 0% to 10% by mass, and even more preferably 0% to 3% by mass, based on the total mass of the negative electrode.

[0075] Furthermore, the binder content (volume fraction) in the positive electrode is preferably 0 vol.% to 42.5 vol.% and even more preferably 0 vol.% to 12 vol.%. The binder content (volume fraction) in the negative electrode is preferably 0 to 42.5 vol.% and even more preferably 0 to 12 vol.%, based on the total volume of the negative electrode. (Other components)

[0076] The electrode for a solid-state battery according to the present invention may contain components other than those described above (hereinafter referred to as "other components"). Examples of the other components include solid electrolytes other than sulfide solid electrolytes. Examples of solid electrolytes other than sulfide solid electrolytes include oxide solid electrolytes and halidic solid electrolytes.

[0077] The oxide solid electrolyte preferably contains oxygen (O) as the main anionic element and may, for example, contain Li, the element Q (Q representing at least one of the elements Nb, B, Al, Si, P, Ti, Zr, Mo, W, or S), and O. Examples of oxide solid electrolytes include garnet-type solid electrolytes, perovskite-type solid electrolytes, NASICON-type solid electrolytes, Li-PO-type solid electrolytes, and Li-BO-type solid electrolytes. Examples of garnet-like solid electrolytes include Li₇La₃Zr₂O₆. 12 , Li 7-x La3(Zr 2-x Nb x )O 12 (0≤x≤2) and Li5La3Nb2O 12 Examples of perovskite-type solid electrolytes include (Li,La)TiO3, (Li,La)NbO3, and (Li,Sr)(Ta,Zr)O3. Examples of NASICON-type solid electrolytes include Li(Al,Ti)(PO4)3 and Li(Al,Ga)(PO4)3. Examples of Li-PO-type solid electrolytes include LisPO4 and LIPON (compounds in which some of the O is in Li). sPO4 is replaced by N). Examples of solid electrolytes of the Li-BO type include Li s BO3 and compounds in which part of the O in Li3BO3 is replaced by C.

[0078] A solid halide electrolyte containing Li, M, and X (where M represents at least one of the elements Ti, Al, or Y, and X represents F, Cl, or Br) is suitable. In particular, Li 6-3z Y z X6 (where X stands for Cl or Br and z 0 <z<2 erfüllt) und Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 <x<1, 0<b≤1,5) vorzuziehen. Unter Li 6-3z Y z From the perspective of excellent lithium-ion conductivity, Li3YX6 (where X represents Cl or Br) is preferred, and Li3YCl6 is even more preferred. Furthermore, from the perspective of factors such as reducing the oxidative decomposition of the sulfide solid electrolyte, it is preferred that Li 6-(4-x)b (Ti 1-x Al x ) bF6 (0 <x<1, 0<b≤1,5) zusammen mit einem Festelektrolyten wie einem Sulfid-Festelektrolyten enthalten ist, und es ist noch bevorzugter, dass Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 <x<1, 0<b≦1,5) mindestens einen Abschnitt der Oberfläche eines Festelektrolyten wie eines Sulfid-Festelektrolyten bedeckt. Diese Konfiguration stellt eine verbesserte Lithium-Ionen-Leitfähigkeit bereit. (Applications)

[0079] The electrode for a solid-state battery according to the present invention can be suitably used as a material that structures the positive electrode or the negative electrode of a solid-state battery. (Solid state battery)

[0080] A solid-state battery according to the present invention comprises a positive electrode layer, a solid electrolyte layer and a negative electrode layer, and at least one of the positive electrode layer or the negative electrode layer is the electrode for a solid-state battery according to the present invention.

[0081] The solid-state battery according to the present invention can comprise a positive electrode current collector on a side of the positive electrode layer that is opposite the side of the solid electrolyte layer.

[0082] The solid-state battery according to the present invention can have a negative electrode current collector on one side of the negative electrode layer that is opposite the side of the solid electrolyte layer. (Positive electrode layer and negative electrode layer)

[0083] At least one of the positive electrode layer or the negative electrode layer of the solid-state battery according to the present invention is the electrode for a solid-state battery according to the present invention.

[0084] The structure of an electrode for a solid-state battery, other than that of the electrode for a solid-state battery according to the present invention, is not particularly restricted and may be a conventionally known structure. Examples of the other electrode include an electrode with the structure described for the electrode for a solid-state battery according to the present invention, except that the specific metal is not included.

[0085] Since the electrode for a solid-state battery according to the present invention is described above, a description is omitted here.

[0086] The thickness of the positive electrode layer is not particularly limited and can, for example, be greater than or equal to 1 nm and less than or equal to 500 µm.

[0087] The thickness of the negative electrode layer is not particularly limited and can be, for example, greater than or equal to 1 nm and less than or equal to 500 µm. (Solid electrolyte layer)

[0088] The solid electrolyte layer can comprise a solid electrolyte. The solid electrolyte layer can have a single-layer structure or a multi-layer structure with two or more layers. The solid electrolyte to be used can be any conventionally known solid electrolyte that can be used in a solid-state battery's solid electrolyte layer; examples include sulfide solid electrolytes.

[0089] The solid electrolyte layer may contain a binder. Examples of binders include rubber-based binders, such as styrene-butadiene rubber, and fluorinated binders, such as polyvinylidene fluoride (PVDF).

[0090] The thickness of the solid electrolyte layer is not particularly limited, and the thickness is, for example, greater than or equal to 1 nm and less than or equal to 500 µm. (Positive electrode current collector)

[0091] The positive electrode current collector to be used can be a conventional, well-known positive electrode current collector. Examples of positive electrode current collector materials include stainless steel, aluminum, nickel, iron, titanium, and carbon, with aluminum alloy foil or aluminum foil being preferred. The aluminum alloy foil and aluminum foil can be produced from a powder. The shape of the positive electrode current collector can be, for example, a foil or a mesh.

[0092] The thickness of the positive electrode current collector is not particularly limited and is, for example, more than or equal to 1 nm and less than or equal to 50 µm. (Negative electrode current collector)

[0093] Any of the metal foils described above can be used as a current collector for the negative electrode. Nickel foil and aluminum foil are preferable.

[0094] The thickness of the negative electrode current collector is not particularly limited, and the thickness is, for example, greater than or equal to 1 nm and less than or equal to 50 µm.

[0095] A schematic cross-sectional view showing an embodiment of the solid-state battery according to the present invention is shown in Fig. 1 shown. As in Fig. Figure 1 shows a negative electrode layer A, a solid electrolyte layer B and a positive electrode layer C layered together.

[0096] In Fig. 1 is an active material for the negative electrode with reference numeral 101, an active material for the positive electrode with reference numeral 103, conductive auxiliary materials with reference numerals 105 and 107, binders with reference numerals 109 and 111, a current collector for the negative electrode with reference numeral 113 and a current collector for the positive electrode with reference numeral 115.

[0097] At least one of the negative electrode layer A or the positive electrode layer C contains the specific metal (not shown).

[0098] The solid-state battery can have a structure in which the layer stack edge surfaces (side surfaces) of the positive electrode / solid electrolyte layer / negative electrode layer structure are sealed by a resin. Both the positive electrode current collector and the negative electrode current collector can have a structure in which a shock-absorbing layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermister layer is arranged on the surface of the current collector.

[0099] Furthermore, the solid electrolyte layer can have a two-layer structure, as in Fig. 1 shown.

[0100] In the following, an embodiment of a method for manufacturing the solid-state battery according to the present invention is described, although the method is not limited to this.

[0101] First, a positive electrode mixture paste, comprising a sulfide solid electrolyte, the specific metal, an active material for the positive electrode, a conductive additive, a binder, and the like, dissolved or dispersed in a given solvent, is coated onto a positive electrode current collector and dried to form a positive electrode layer. This produces a positive electrode foil comprising the positive electrode current collector and the positive electrode layer.

[0102] Next, a negative electrode mixture paste, comprising a sulfide solid electrolyte, the specific metal, an active material for the negative electrode, a conductive additive, a binder, and the like, dissolved or dispersed in a given solvent, is coated onto a surface of a negative electrode current collector and dried to form a negative electrode layer. This produces a negative electrode sheet comprising the negative electrode current collector and the negative electrode layer.

[0103] Next, a paste for a solid electrolyte layer, comprising a solid electrolyte, a binder, and the like, dissolved or dispersed in a specific solvent, is coated onto a metal foil, such as aluminum foil or SUS foil, and dried to form a solid electrolyte layer. In this way, a solid electrolyte sheet is produced, comprising the metal foil and the solid electrolyte layer.

[0104] The negative electrode layer and the solid electrolyte layer are then stacked and pressed together, transferring the solid electrolyte layer to the surface of the negative electrode layer.

[0105] Next, the positive electrode layer is layered and pressed onto one side of the solid electrolyte layer opposite the negative electrode layer, thus producing the solid-state battery.

[0106] The solid-state battery produced by the method described above comprises the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer and the negative electrode current collector in that order.

[0107] Examples of the aforementioned solvents include water, N-methyl-2-pyrrolidone, butyl butyrate, tetrahydronaphthalene, heptane, dibutyl ether and diisobutyl ketone (DIBK). EXAMPLES

[0108] The present invention is described in more detail below with reference to examples, but the present disclosure is not limited to these examples. <Beispiele 1 bis 7>

[0109] LiNi was used as the active material for the positive electrode. 0,8 (CoAl) 0,2 O2 was provided, which had undergone an LTAF (Li-Ti-Al-F) surface treatment.

[0110] The active material of the positive electrode, conductive carbon, a solid electrolyte (glass ceramic based on Li2S-P2S5-LiBr-Lil), a binder (styrene-butadiene rubber (SBR)), a solvent (tetrahydronaphthalene) and copper were mixed using an ultrasonic homogenizer (UH-50 from SMT Co., Ltd) to obtain a mixing paste for the positive electrode.

[0111] The contents (volume fractions) of the active material of the positive electrode and of the copper were adjusted as specified in Table 1. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that their total quantity corresponded to the quantity specified in the row for "other components" in Table 1. The solvent was added in such a quantity that the solvent content is 25 parts by mass when the sum of the contents of the active material of the positive electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0112] Li4T5O was used as the active material for the negative electrode. 12 provided.

[0113] The active material of the negative electrode, conductive carbon, a solid electrolyte, a binder, and a solvent, were mixed using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a mixing paste for the negative electrode. The solid electrolyte, binder, and solvent were the same as those used for the positive electrode mixing paste.

[0114] The content (volume fraction) of the active material of the negative electrode was determined as specified in Table 1. To compensate, the amounts of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount corresponded to the quantity specified in the "Other Ingredients" row of Table 1. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, and binder is assumed to be 100 parts by mass.

[0115] 51 parts by mass of a solvent, 3 parts by mass of a solution containing 5% by mass of a binder, and 46 parts by mass of a Lil-LiBr-Li₂S-P₂S₅-based glass-ceramic serving as a solid electrolyte were placed in a polypropylene container and mixed for 30 seconds using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.). The binder and solvent were the same as those used for the positive electrode mixing paste. The container was then shaken for 3 minutes to obtain a solid electrolyte paste.

[0116] The positive electrode mixture paste was applied to an aluminum foil using a blade applicator. After application, the paste was dried for 30 minutes on a hot press at 100 °C to create a positive electrode foil with a positive electrode layer on the surface of the aluminum foil.

[0117] Similarly, the negative electrode mixing paste was applied to an aluminum foil and dried to obtain a negative electrode plate with a negative electrode layer.

[0118] Similarly, the solid electrolyte paste was applied to an aluminum foil and dried to obtain a solid electrolyte sheet with a solid electrolyte layer. In this process, the mass per unit area of ​​the negative electrode was adjusted so that the specific charge capacity of the negative electrode was 1 times the specific charge capacity of the positive electrode layer when the specific charge capacity of the positive electrode layer was set to 200 mAh / g.

[0119] By layering the negative electrode layer and the solid electrolyte layer and pressing, the solid electrolyte layer was transferred to the surface of the negative electrode layer.

[0120] The positive electrode foil was then layered onto one side of the solid electrolyte layer opposite the side of the negative electrode layer, and the roller pressing was carried out at 175 °C and 5 tonnes / cm², resulting in a layered body.

[0121] The layered body contained the aluminum foil, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the aluminum foil in that order.

[0122] The resulting layered body was sealed with a laminate and subjected to a load of 5 MPa to obtain a solid-state lithium-ion secondary battery, or lithium-ion secondary solid-state battery.

[0123] The solid-state lithium-ion secondary battery was stored for seven days at an ambient temperature of 80 °C. This step corresponds to a heat treatment of the solid-state battery. <Beispiele 8 bis 16>

[0124] An active positive electrode material, conductive carbon, a solid electrolyte, a binder, and a solvent were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a positive electrode mixing paste. The respective components were the same as in Example 1.

[0125] The content (volume fraction) of the active material in the positive electrode was adjusted as specified in Table 1. To compensate, the amounts of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount was the quantity specified in the "other components" row of Table 1. The solvent was added in such a quantity that the solvent content is 25 parts by mass when the sum of the contents of the active material in the positive electrode, the conductive carbon, the solid electrolyte, and the binder is assumed to be 100 parts by mass.

[0126] An active material for the negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a mixing paste for the negative electrode. The respective components were the same as in Example 1.

[0127] Here, the contents (volume fractions) of the active material of the negative electrode and of the copper were adjusted as specified in Table 1. To compensate, the amounts of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount was the amount specified in the row for "other components" in Table 1. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0128] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 1, except that the positive and negative electrode mixing pastes described above were used. The battery was then left to stand under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <Vergleichsbeispiel 1>

[0129] An active positive electrode material, conductive carbon, a solid electrolyte, a binder, and a solvent were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a positive electrode mixing paste. The respective components were the same as in Example 1.

[0130] The content (volume fraction) of the active material in the positive electrode was adjusted as specified in Table 1. To compensate, the amounts of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount was the quantity specified in the "other components" row of Table 1. The solvent was added in such a quantity that the solvent content is 25 parts by mass when the sum of the contents of the active material in the positive electrode, the conductive carbon, the solid electrolyte, and the binder is assumed to be 100 parts by mass.

[0131] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 1, except that the positive electrode mixing paste described above was used. The battery was then left to stand under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <Vergleichsbeispiel 2>

[0132] An active material for a negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were blended using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a paste for a negative electrode. The respective components were the same as in Example 1.

[0133] Here, the contents (volume fractions) of the active material of the negative electrode and of copper were adjusted as specified in Table 1. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total quantity was the amount specified in the row for "other components" in Table 1. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0134] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 8, except that the negative electrode mixing paste described above was used. The battery was then stored under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <<Bewertung des Widerstands> >

[0135] The obtained solid-state lithium-ion secondary battery was placed in a thermostatic tank set to 25 °C and connected to a charging / discharging device.

[0136] The battery was subjected to a constant current charge at 0.1C, and after the cell voltage reached 2.7V, it was subjected to a constant voltage charge. The constant voltage charge test was terminated when the current reached a value corresponding to 0.01C.

[0137] A constant current discharge at 0.1C was then performed until the cell voltage dropped to 2.12V, corresponding to the SOC40, followed by a constant voltage discharge at 2.12V. The constant voltage discharge was terminated when the current reached 0.01C.

[0138] A constant current discharge was then performed at 72 C, and the DC resistance was calculated from the voltage after 0.1 seconds based on Ohm's law.

[0139] The ratios of the resistance values ​​of the respective examples and the respective comparison examples, where the resistance value of the lithium-ion secondary solid battery of comparison example 1 is assumed to be 100%, are shown in Table 1. Table 1 Content (relative to volume) of the respective components in the positive electrode layer Content (relative to volume) of the respective components in the negative electrode layer Resistance rating (%) active material of the positive electrode (other components) copper active material of the negative electrode (other components) copper Example 1 57,0% 43,0% 5 ppm 62,5% 37,5% - 97,97 Example 2 57,0% 43,0% 20 ppm 62,5% 37,5% - 95,22 Example 3 57,0% 43,0% 100 ppm 62,5% 37,5% - 93,59 Example 4 57,0% 43,0% 500 ppm 62,5% 37,5% - 87,24 Example 5 56,9% 43,0% 1,000 ppm 62,5% 37,5% - 81,39 Example 6 56,9% 42,9% 2,000 ppm 62,5% 37,5% - 80,84 Example 7 56,7% 42,8% 5,000 ppm 62,5% 37,5% - 85,56 Example 8 57,0% 43,0% - 62,5% 37,5% 5 ppm 90,53 Example 9 57,0% 43,0% - 62,5% 37,5% 20 ppm 88,16 Example 10 57,0% 43,0% - 62,5% 37,5% 50 ppm 84,21 Example 11 57,0% 43,0% - 62,5% 37,5% 100 ppm 82,99 Example 12 57,0% 43,0% - 62,4% 37,5% 250 ppm 81,66 Example 13 57,0% 43,0% - 62,4% 37,5% 500 ppm 79,44 Example 14 57,0% 43,0% - 62,4% 37,5% 1,000 ppm 78,87 Example 15 57,0% 43,0% - 62,3% 37,5% 2,000 ppm 81,55 Example 16 57,0% 43,0% - 62,1% 37,4% 5,000 ppm 82,12 Comparison example 1 57,0% 43,0% - 62,5% 37,5% - 100 Comparison example 2 57,0% 43,0% - 61,8% 37,2% 10,000 ppm 111,9

[0140] The results in Table 1 show that the solid-state batteries in the examples where the copper content is greater than or equal to 5 ppm by volume exhibit lower resistance after heat treatment, and thus a reduction in the increase in resistance, compared to the solid-state battery in comparison example 1, which does not contain the metal. Furthermore, it can be seen that the solid-state batteries in the examples where the copper content is less than 10,000 ppm by volume exhibit lower resistance after heat treatment, and thus a reduction in the increase in resistance, compared to the solid-state battery in comparison example 2, where the copper content exceeds this range.

[0141] Note that details of the test to confirm that copper is a metal that reacts with a sulfide solid electrolyte to show electronic conductivity will be described later. <Beispiele 17 bis 20 und Vergleichsbeispiele 3 und 4>

[0142] An active material for a negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and silver were blended using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a mixing paste for a negative electrode. The respective components were the same as in Example 1.

[0143] Here, the contents (volume fractions) of the active material of the negative electrode and of the silver were adjusted as specified in Table 2. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total quantity was the amount specified in the "Other Ingredients" row of Table 2. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, binder, and silver is assumed to be 100 parts by mass.

[0144] A solid-state lithium-ion secondary battery was obtained in the same way as in Example 8, except that the negative described above was used.

[0145] Electrode mixing paste was used. Afterwards, the battery was stored under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <<Bewertung des Widerstands> >

[0146] The evaluation of the resistance of the obtained solid-state lithium-ion secondary battery was carried out in the same way as in Example 1.

[0147] The ratios of the resistance values ​​of the respective examples and the respective comparison examples, where the resistance value of the lithium-ion secondary solid battery of comparison example 1 is assumed to be 100%, are shown in Table 2. Table 2 Content (relative to volume) of the respective components in the positive electrode layer Content (relative to volume) of the respective components in the negative electrode layer Resistance rating (%) active material of the positive electrode (other components) Silver active material of the negative electrode (other components) Silver Example 17 57,0% 43,0% - 62,5% 37,5% 5 ppm 98,49 Example 18 57,0% 43,0% - 62,5% 37,5% 100 ppm 84,75 Example 19 57,0% 43,0% - 62,3% 37,5% 2,000 ppm 87,48 Example 20 57,0% 43,0% - 62,1% 37,4% 5,000 ppm 88,48 Comparison example 3 57,0% 43,0% - 61,8% 37,2% 10,000 ppm 108,81 Comparison example 4 57,0% 43,0% - 61,2% 36,8% 20,000 ppm 126,48

[0148] The results in Table 2 show that the solid-state batteries of the examples, in which the content of the metal (silver), based on the total volume of the electrode for a solid-state battery, is greater than or equal to 5 ppm by volume and less than 10,000 ppm by volume, exhibit a lower resistance after heat treatment and thus a reduction in the resistance increase than the solid-state batteries of the comparison examples, in which the metal (silver) was present in an amount greater than or equal to 10,000 ppm by volume.

[0149] Note that the details of the test to confirm that silver is a metal that reacts with a sulfide solid electrolyte to show electronic conductivity will be described later. <Vergleichsbeispiele 5 bis 8>

[0150] An active material for a negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and stainless SUS 316 were blended using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a mixing paste for a negative electrode. The respective components were the same as in Example 1.

[0151] Here, the contents (volume fractions) of the active material of the negative electrode and the stainless steel SUS 316 were adjusted as specified in Table 3. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount of these components corresponded to the quantity specified in the row for "other components" in Table 3. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, the conductive carbon, the solid electrolyte, the binder, and the stainless steel SUS 316 is assumed to be 100 parts by mass.

[0152] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 8, except that the negative electrode mixing paste described above was used. The battery was then stored under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <<Bewertung des Widerstands> >

[0153] The evaluation of the resistance of the obtained solid-state lithium-ion secondary battery was carried out in the same way as in Example 1.

[0154] The ratios of the resistance values ​​of the respective comparison examples, where the resistance value of the solid-state lithium-ion secondary battery of comparison example 1 is assumed to be 100%, are shown in Table 3. Table 3 Content (relative to volume) of the respective components in the positive electrode layer Content (relative to volume) of the respective components in the negative electrode layer Resistance rating (%) active material of the positive electrode (other components) stainless SUS 316 active material of the negative electrode (other components) stainless SUS 316 Comparison example 5 57,0% 43,0% - 62,5% 37,5% 100 ppm 102,17 Comparison example 6 57,0% 43,0% - 62,4% 37,5% 500 ppm 103,82 Comparative example 7 57,0% 43,0% - 62,4% 37,5% 1,000 ppm 112,27 Comparative example 8 57,0% 43,0% - 62,3% 37,5% 2,000 ppm 116,76

[0155] The results in Table 3 show that the solid-state batteries in the comparison examples, which contained stainless SUS 316 in the electrode for a solid-state battery, exhibited high resistance after heat treatment and showed no reduction in the increase in resistance.

[0156] The details of the test to confirm that stainless SUS 316 is not a metal that reacts with a sulfide solid electrolyte to show electronic conductivity will be described later. <Vergleichsbeispiele 9 bis 10>

[0157] An active positive electrode material, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a positive electrode mixing paste. The respective components were the same as in Example 1.

[0158] Here, the contents (volume fractions) of the active material of the positive electrode and of the copper were adjusted as specified in Table 4. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total quantity was the amount specified in the "Other Ingredients" row of Table 4. The solvent was added in such a quantity that the solvent content is 25 parts by mass when the sum of the contents of the active material of the positive electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0159] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 1, except that the positive electrode mixing paste described above was used. The battery was then left to stand under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <Vergleichsbeispiel 11>

[0160] An active material for a negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were blended using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a paste for a negative electrode. The respective components were the same as in Example 1.

[0161] Here, the contents (volume fractions) of the active material of the negative electrode and of the copper were adjusted as specified in Table 4. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total quantity was the amount specified in the "Other Ingredients" row of Table 4. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0162] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 1, except that the negative electrode mixing paste described above was used. The battery was then left to stand under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <<Bewertung der Reduzierung des Kurzschlusses (Bewertung der Selbstentladungsmenge)> >

[0163] The obtained solid-state lithium-ion secondary battery was placed in a thermostatic tank set to 25 °C and connected to a charging / discharging device.

[0164] A constant voltage charge was performed at 2.515 V. The constant voltage charge was terminated when the current dropped to 0.01 C. The battery voltage was then measured as open-circuit voltage for 72 hours. The amount of voltage drop over the 24-hour period from 48 hours to 72 hours was calculated as the self-discharge rate.

[0165] The self-discharge measurement described above was performed on the batteries in Examples 3 to 7, Examples 11 to 16, and the comparison examples 1, 2, and 9 to 11. The results are summarized in Table 4. Table 4 Content (relative to volume) of the respective components in the positive electrode layer Content (relative to volume) of the respective components in the negative electrode layer Resistance rating (%) active material of the positive electrode (other components) copper active material of the negative electrode (other components) copper Example 3 57,0% 43,0% 100 ppm 62,5% 37,5% - 2,17 Example 4 57,0% 43,0% 500 ppm 62,5% 37,5% - 2,28 Example 5 56,9% 43,0% 1,000 ppm 62,5% 37,5% - 3,54 Example 6 56,9% 42,9% 2,000 ppm 62,5% 37,5% - 4,31 Example 7 56,7% 42,8% 5,000 ppm 62,5% 37,5% - 9,05 Example 11 57,0% 43,0% - 62,5% 37,5% 100 ppm 2,50 Example 12 57,0% 43,0% - 62,4% 37,5% 250 ppm 2,50 Example 13 57,0% 43,0% - 62,4% 37,5% 500 ppm 2,63 Example 14 57,0% 43,0% - 62,4% 37,5% 1,000 ppm 2,75 Example 15 57,0% 43,0% - 62,3% 37,5% 2,000 ppm 27,63 Example 16 57,0% 43,0% - 62,1% 37,4% 5,000 ppm 61,00 Comparison example 1 57,0% 43,0% - 62,5% 37,5% - 2,20 Comparative example 9 56,4% 42,6% 10,000 ppm 62,5% 37,5% - 67,80 Comparative example 10 55,9% 42,1% 20,000 ppm 62,5% 37,5% - 508,50 Comparison example 2 57,0% 43,0% - 61,8% 37,2% 10,000 ppm 60,25 Comparative example 11 57,0% 43,0% - 61,2% 36,8% 20,000 ppm 564,55

[0166] The results in Table 4 show that the solid-state batteries of Examples 3 to 6 and Examples 11 to 15, in which the content of the metal (copper) was less than or equal to 4,000 ppm by volume, exhibited low self-discharge and improved short-circuit reduction compared to the solid-state batteries of Examples 7, 16 and the comparison examples, in which the metal (copper) was present in an amount greater than 4,000 ppm by volume. <Beispiele 21 bis 25>

[0167] An active positive electrode material, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a positive electrode mixing paste. The respective components were the same as in Example 1.

[0168] Here, the contents (volume fractions) of the active material of the positive electrode and of the copper were adjusted as specified in Table 5. The remaining amounts of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total amount corresponded to the quantity specified in the row for "other components" in Table 5. The solvent was added in such a quantity that the solvent content is 25 parts by mass, assuming a total of 100 parts by mass for the active material of the positive electrode, conductive carbon, solid electrolyte, binder, and copper.

[0169] An active material for the negative electrode, conductive carbon, a solid electrolyte, a binder, a solvent, and copper were mixed together using an ultrasonic homogenizer (UH-50, manufactured by SMT Co., Ltd.) to obtain a mixing paste for the negative electrode. The respective components were the same as in Example 1.

[0170] Here, the contents (volume fractions) of the active material of the negative electrode and of copper were adjusted as specified in Table 5. To compensate, the quantities of conductive carbon, solid electrolyte, and binder were adjusted accordingly so that the total quantity was the amount specified in the row for "other components" in Table 5. The solvent was added in such a quantity that the solvent content is 35 parts by mass when the sum of the contents of the active material of the negative electrode, conductive carbon, solid electrolyte, binder, and copper is assumed to be 100 parts by mass.

[0171] A solid-state lithium-ion secondary battery was prepared in the same manner as in Example 1, except that the positive and negative electrode mixing pastes described above were used. The battery was then left to stand under the same conditions as in Example 1, i.e., for seven days at an ambient temperature of 80 °C. <<Bewertung des Widerstands> >

[0172] The evaluation of the resistance of the obtained solid-state lithium-ion secondary battery was carried out in the same way as in Example 1.

[0173] The ratios of the resistance values ​​of the respective examples, since the resistance value of the solid-state lithium-ion secondary battery of comparison example 1 is assumed to be 100%, are shown in Table 5. <<Bewertung der Reduzierung des Kurzschlusses (Bewertung der Selbstentladungsmenge)> >

[0174] The evaluation of the reduction in short circuits of the resulting solid-state lithium-ion secondary battery was carried out in the same manner as in Example 1. The results for the self-discharge rates are shown in Table 5. Table 5 Content (relative to volume) of the respective components in the positive electrode layer Content (relative to volume) of the respective components in the negative electrode layer Resistance rating (%) Assessment of short-circuit reduction (assessment of self-discharge rate) [mV / day] active material of the positive electrode (other components) copper active material of the negative electrode (other components) copper Example 21 57,0% 43,0% 50 ppm 62,5% 37,5% 50 ppm 89,70 2,28 Example 22 57,0% 43,0% 100 ppm 62,5% 37,5% 100 ppm 86,93 2,80 Example 23 57,0% 43,0% 200 ppm 62,4% 37,5% 200 ppm 80,63 2,53 Example 24 57,0% 43,0% 500 ppm 62,4% 37,5% 500 ppm 82,10 2,07 Example 25 56,9% 43,0% 1,000 ppm 62,4% 37,5% 1,000 ppm 84,10 2,25 <<Verification that the metal is the specific metal>>

[0175] In accordance with the verification method described above, it was determined whether each of the metals copper, silver, and stainless SUS 316 used in the examples described above, as well as nickel, aluminum, gold, iron, platinum, and zinc not used in the examples described above, is a metal that reacts with a sulfide solid electrolyte to exhibit electronic conductivity (i.e., is the specific metal) or not. The results regarding the measured rate of increase in electronic conductivity during heat treatment are presented in Table 6. Table 6 Metal species Initial electron conductance [S / cm] Electron conductance after heat treatment [S / cm] Rate of increase in electron conductance during heat treatment Silver 2,09E-08 1,15E-07 5,50 nickel 3,70E-09 2,58E-03 695984,53 SUS316 2,08E-09 4,39E-09 2,11 copper 1,67E-08 4,27E-04 25583,58 Aluminum 1,62E-09 4,05E-09 2,50 Gold 5,58E-09 1,45E-08 2,60 iron 3,31 E-09 1,67E-07 50,50 Platinum 1,64E-09 4,28E-09 2,60 zinc 4,50E-09 9,77E-09 2,17

[0176] In Fig. The reference symbols 1 each represent the following elements. A negative electrode layer B Solid electrolyte layer C positive electrode layer 101 active material of the negative electrode 103 active material of the positive electrode 105 and 107 Conductive aid 109 and 111 Binders 113 negative electrode current collectors 115+ positive electrode current collector QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2020 191 183 A

[0005] JP 2013-16 423 A

[0041] Cited non-patent literature

[0000] Kanno et al., Journal of The Electrochemical Society, 148(7) A742-746 (2001)), and crystal structures (see Solid State onics, 177(2006), 2721-2725

[0041]

Claims

[1] Electrode for a solid-state battery, comprising: a sulfidic solid electrolyte; and a metal that reacts with the sulfidic solid electrolyte to exhibit electronic conductivity, wherein the content of the metal, based on the total volume of the electrode for a solid-state battery, is greater than or equal to 5 ppm by volume and less than 10,000 ppm by volume. [2] The electrode for an all-solid-state battery according to claim 1, wherein the metal is at least one metal selected from the group consisting of copper, silver, nickel, iron, tin, aluminum, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum and their alloys. [3] The electrode for an all-solid-state battery according to claim 2, wherein the metal is at least one of copper or silver. [4] The electrode for an all-solid-state battery according to any one of claims 1 to 3, wherein the content of the metal, based on the total volume of the electrode for an all-solid-state battery, is greater than or equal to 50 ppm by volume. [5] The electrode for an all-solid-state battery according to any one of claims 1 to 4, wherein the content of the metal, based on the total volume of the electrode for an all-solid-state battery, is less than or equal to 5,000 ppm by volume. [6] An electrode for an all-solid-state battery according to any one of claims 1 to 5, wherein the sulfide solid electrolyte contains a phosphorus atom. [7] An all-solid-state battery comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, wherein at least one of the positive electrode layer or the negative electrode layer is the electrode for an all-solid-state battery according to any one of claims 1 to 6.

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