Solid electrolyte, method for manufacturing same, and all-solid-state battery comprising same

Abstract

The present invention relates to a solid electrolyte comprising a sulfide-based lithium ion conductive compound containing lithium (Li), phosphorus (P), sulfur (S), a halogen element (D), and oxygen (O) and having an argyrodite-based crystal structure, wherein the lithium ion conductive compound satisfies expression 1 below. [Expression 1] 5.7≤([S]+[D]) / [P]≤5.9 In expression 1, [S] denotes the mole fraction of sulfur in the lithium ion conductive compound, [D] denotes the mole fraction of the halogen element in the lithium ion conductive compound, and [P] denotes the mole fraction of phosphorus in the lithium ion conductive compound.

Description

Solid electrolyte, method for manufacturing the same, and all-solid-state battery including the same

[0001] This application claims priority to Korean Patent Application No. 10-2024-0190802 filed on December 19, 2024, and the contents of said priority application are all incorporated into this specification.

[0002] The present invention relates to a solid electrolyte, a method for manufacturing the same, and an all-solid-state battery comprising the same.

[0003] As research on the safety issues and energy density of high-capacity batteries gains attention, all-solid-state batteries are being hailed as the next generation of batteries.

[0004] The above-described all-solid-state battery is a battery that ensures safety by replacing the liquid electrolyte, which causes explosions, with a solid electrolyte, thereby eliminating the use of flammable solvents within the battery and preventing any ignition or explosion caused by reactions such as the decomposition reaction of conventional electrolytes.

[0005] In addition, since lithium metal or lithium alloy can be used as the cathode material, the energy density relative to the mass and volume of the battery can be improved.

[0006] Inorganic solid electrolytes are generally used as the solid electrolytes in the aforementioned all-solid-state batteries, and various studies are currently underway regarding sulfide-based solid electrolytes having a composition such as Li6PS5Cl, which has an argyrodite structure, among the aforementioned all-solid-state batteries.

[0007] Although azirodite-based sulfide solid electrolytes possess high lithium ion conductivity, they have a problem with poor moisture stability, such as a sharp decrease in ion conductivity due to the sensitive reaction of sulfur (S) among their constituent elements with atmospheric moisture.

[0008] Furthermore, Li2S, the primary raw material for azirodite-based sulfide solid electrolytes, is expensive and prone to adverse reactions with atmospheric moisture. Consequently, handling difficulties exist, such as the deterioration of the electrochemical properties of the final solid electrolyte if storage is not strictly controlled. Therefore, there is a need for measures that can reduce the amount of Li2S used as a solid electrolyte raw material while minimizing adverse reactions with atmospheric moisture during the process.

[0009]

[0010] Accordingly, one objective of the present invention is to provide a sulfide-based lithium ion conductive compound solid electrolyte that has improved moisture stability and excellent ion conductivity, while reducing the amount of Li2S used as a raw material and the side reaction of Li2S with atmospheric moisture, a method for manufacturing the same, and an all-solid-state battery including the same.

[0011]

[0012] One embodiment of the present invention provides a solid electrolyte comprising a sulfide-based lithium ion conductive compound having an argyrodite-based crystal structure and containing lithium (Li), phosphorus (P), sulfur (S), a halogen element (D), and oxygen (O), wherein the lithium ion conductive compound satisfies Formula 1 below.

[0013] [Equation 1]

[0014] 5.7≤([S]+[D]) / [P]≤5.9

[0015] In the above Equation 1, [S] is the mole fraction of sulfur in the lithium ion conductive compound, [D] is the mole fraction of a halogen element in the lithium ion conductive compound, and [P] is the mole fraction of phosphorus in the lithium ion conductive compound.

[0016]

[0017] The above lithium ion conductive compound can satisfy Formula 2 below.

[0018] [Equation 2]

[0019] 0.004≤[O] / ([Li]+[P]+[S]+[D])≤0.1

[0020] In the above Equation 2, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, [S] is the mole fraction of sulfur in the lithium ion conductive compound, and [D] is the mole fraction of a halogen element in the lithium ion conductive compound.

[0021]

[0022] The above lithium ion conductive compound can satisfy Formula 3 below.

[0023] [Equation 3]

[0024] 0.004≤[O] / ([Li]+[P]+[S])≤0.12

[0025] In the above Equation 3, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, and [S] is the mole fraction of sulfur in the lithium ion conductive compound.

[0026]

[0027] The above lithium ion conductive compound can be represented by the following chemical formula 1.

[0028] [Chemical Formula 1]

[0029] Li7-5a-7b-x(1-ab)P (1-a-b)+2b S (1-a-b)(6-x) O a+5b D (1-a-b)x

[0030] In the above chemical formula 1, D is a halogen element such as F, Cl, Br, I, or a combination thereof, 1≤x≤2, 0.005≤a≤0.6, and 0.005≤b≤0.04.

[0031]

[0032] Another embodiment of the present invention comprises the steps of: forming a mixture by grinding and mixing a lithium raw material, a phosphorus raw material, a halogen element raw material, and an oxygen raw material; and heat-treating the mixture to form a sulfide-based lithium ion conductive compound having an argyrodite-based crystal structure, wherein the oxygen raw material is Li2O, P2O5, and Li2SO -4 A method for manufacturing a solid electrolyte including is provided.

[0033] The above grinding and mixing can be performed using a table mill.

[0034] The above grinding and mixing can be performed for 3 to 22 hours.

[0035] The above heat treatment can be performed at a temperature of 370 to 480°C.

[0036]

[0037] Another embodiment of the present invention provides an all-solid-state battery comprising: an anode layer; a cathode layer; and a solid electrolyte layer located between the anode layer and the cathode layer, wherein at least one of the anode layer, the cathode layer, and the solid electrolyte layer comprises the aforementioned solid electrolyte.

[0038]

[0039] In a solid electrolyte according to one embodiment of the present invention, as oxygen is doped in an appropriate amount within the argyrodite-based crystal structure, moisture stability is improved and the deterioration of ion conductivity can be minimized.

[0040] A method for manufacturing a solid electrolyte according to one embodiment of the present invention comprises Li2O, P2O5, and Li2SO₄ as oxygen source materials. -4 Oxygen in the solid electrolyte can be doped in an appropriate amount using [this method].

[0041] In addition, the solid electrolyte and the method for manufacturing the same according to one embodiment of the present invention can replace a portion of Li2S with Li2O as a lithium source, thereby reducing the amount of Li2S used, which is expensive and difficult to handle in the atmosphere.

[0042] In addition, the method for manufacturing a solid electrolyte according to one embodiment of the present invention can reduce side reactions of Li2S with atmospheric moisture and enables low-temperature calcination by performing the grinding and mixing of raw materials using a table mill. Accordingly, the ionic conductivity and moisture stability of the solid electrolyte can be comprehensively improved, and productivity and economic efficiency can be enhanced.

[0043]

[0044] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0045] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0046] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0047] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0048] Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

[0049] In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components.

[0050] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0051]

[0052] 1. Solid electrolyte

[0053] A solid electrolyte according to one embodiment of the present invention comprises a sulfide-based lithium ion conductive compound having an argyrodite-based crystal structure.

[0054] Whether a solid electrolyte has an azirodite-based crystal structure can be confirmed, for example, by XRD measurement. That is, in the X-ray diffraction pattern measured by an X-ray diffraction device (XRD) using CuKα1 rays, the crystal phase of the azirodite-based crystal structure has characteristic peaks at 2θ=15.34°±1.00°, 17.74°±1.00°, 25.19°±1.00°, 29.62°±1.00°, 30.97°±1.00°, 44.37°±1.00°, 47.22°±1.00°, and 51.70°±1.00°. In addition, for example, it has characteristic peaks at 2θ=54.26°±1.00°, 58.35°±1.00°, 60.72°±1.00°, 61.50°±1.00°, 70.46°±1.00°, and 72.61°±1.00°. Meanwhile, the fact that the solid electrolyte does not contain a crystal phase of an azirodite-based crystal structure can be confirmed by not having a characteristic peak of the crystal phase of the azirodite-based crystal structure described above.

[0055] The statement that a solid electrolyte has an azirodite-based crystal structure means that the solid electrolyte has at least a crystal phase of an azirodite-based crystal structure. In the present invention, it is preferable that the solid electrolyte has a crystal phase of an azirodite-based crystal structure as a main phase. At this time, "main phase" refers to the phase that has the largest proportion relative to the total amount of all crystal phases constituting the solid electrolyte. Accordingly, the content ratio of the crystal phase of an azirodite-based crystal structure contained in the solid electrolyte is preferably, for example, 60 mass% or more relative to the total crystal phases constituting the solid electrolyte, and among them, it is more preferable to have 70 mass% or more, 80 mass% or more, or 90 mass% or more. In addition, the ratio of the crystal phase can be confirmed, for example, by XRD.

[0056] More specifically, the lithium ion conductive compound according to the present invention may be an argyrodite-based crystal structure compound containing lithium (Li), phosphorus (P), sulfur (S), and a halogen element (D).

[0057] However, although argyrodite-based crystal structure sulfide compounds exhibit excellent lithium ion conductivity, they have a problem with poor moisture stability, as sulfur reacts with atmospheric moisture to generate H2S gas, causing lattice structure degradation and a sharp decrease in ion conductivity.

[0058] Accordingly, the lithium ion conductive compound according to the present invention has an azirodite-based crystal structure, and by further containing oxygen (O) which has low reactivity with moisture in the atmosphere, the lattice structure is stabilized and moisture stability can be improved.

[0059] In particular, the lithium ion conductive compound according to the present invention comprises Li2O, P2O5, and Li2SO as oxygen source materials. -4 It may be manufactured using Li2O, P2O5, and Li2SO₄ as oxygen source materials. -4 By using a combination of these materials, the ratio of phosphorus, lithium, sulfur, and oxygen, which act as structural frames compared to the use of each material alone, can be appropriately controlled, allowing for the synthesis of a more stable composition, which in turn enables the desirable realization of structural stabilization effects and thus enables more desirable moisture stability.

[0060] In addition, the lithium ion conductive compound according to the present invention comprises Li2O, P2O5, and Li2SO as oxygen source materials. -4 By using a combination of these, a unique composition different from conventional oxygen-doped azirodite compounds can be obtained.

[0061] Specifically, the lithium ion conductive compound according to the present invention satisfies Formula 1 below.

[0062] [Equation 1]

[0063] 5.7≤([S]+[D]) / [P]≤5.9

[0064] In the above Equation 1, [S] is the mole fraction of sulfur in the lithium ion conductive compound, [D] is the mole fraction of a halogen element in the lithium ion conductive compound, and [P] is the mole fraction of phosphorus in the lithium ion conductive compound.

[0065]

[0066] The ([S]+[D]) / [P] value can vary sharply depending on the amount of oxygen source material added during solid electrolyte manufacturing; specifically, it may decrease as the amount of oxygen source material added increases. If the ([S]+[D]) / [P] value is too small, it implies that the amount of oxygen source material added is too large, which may lead to excessive deformation of the basic azirodite crystal structure and deterioration of ionic conductivity. If the ([S]+[D]) / [P] value is too large, it implies that the amount of oxygen source material added is too small, which may result in a negligible improvement in moisture stability due to oxygen doping.

[0067] More specifically, the above ([S]+[D]) / [P] value may be 5.8 to 5.878, in which case the moisture stability and ionic conductivity of the solid electrolyte may be more preferably realized.

[0068]

[0069] In addition, the lithium ion conductive compound according to the present invention can satisfy Formula 2 below.

[0070] [Equation 2]

[0071] 0.004≤[O] / ([Li]+[P]+[S]+[D])≤0.1

[0072] In the above Equation 2, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, [S] is the mole fraction of sulfur in the lithium ion conductive compound, and [D] is the mole fraction of a halogen element in the lithium ion conductive compound.

[0073] The [O] / ([Li]+[P]+[S]+[D]) value represents the ratio of the moles of oxygen to the total moles of constituent elements excluding oxygen within the compound. In other words, this value can increase or decrease in proportion to the increase or decrease in the amount of oxygen doping. If the [O] / ([Li]+[P]+[S]+[D]) value is too small, it implies that the amount of oxygen doping is too low, meaning the improvement in water stability due to oxygen doping may be negligible. If the [O] / ([Li]+[P]+[S]+[D]) value is too large, it implies that the amount of oxygen doping is too high, which may lead to excessive deformation of the underlying azirodite crystal structure and deterioration of ionic conductivity.

[0074] The above [O] / ([Li]+[P]+[S]+[D]) value may be more specifically 0.007 to 0.03, in which case the moisture stability and ionic conductivity of the solid electrolyte may be more preferably realized.

[0075]

[0076] In addition, the lithium ion conductive compound according to the present invention can satisfy Formula 3 below.

[0077] [Equation 3]

[0078] 0.004≤[O] / ([Li]+[P]+[S])≤0.12

[0079] In the above Equation 3, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, and [S] is the mole fraction of sulfur in the lithium ion conductive compound.

[0080] The [O] / ([Li]+[P]+[S]) value may represent the ratio of the moles of oxygen to the total moles of constituent elements, excluding oxygen and halogen elements, within the compound. If the [O] / ([Li]+[P]+[S]) value is too small, the effect of improving moisture stability may be negligible. If the [O] / ([Li]+[P]+[S]) value is too large, ionic conductivity may deteriorate.

[0081] More specifically, the [O] / ([Li]+[P]+[S]) value may be 0.007 to 0.05, in which case the moisture stability and ionic conductivity of the solid electrolyte may be more preferably realized.

[0082]

[0083] Meanwhile, the lithium ion conductive compound according to the present invention can be represented more specifically by the following chemical formula 1.

[0084] [Chemical Formula 1]

[0085] Li7-5a-7b-x(1-ab)P (1-a-b)+2b S (1-a-b)(6-x) O a+5b D (1-a-b)x

[0086] In the above chemical formula 1, D is a halogen element such as F, Cl, Br, I, or a combination thereof, 1≤x≤2, 0.005≤a≤0.6, and 0.005≤b≤0.04.

[0087] In the above chemical formula 1, x is 1 ≤ x ≤ 2. x can increase or decrease in proportion to the increase or decrease in the amount of halogen raw material input. If x is too small, the halogen content is too low, and the ionic conductivity of the solid electrolyte may deteriorate. If x is too large, the halogen content is high, and while the ionic conductivity of the solid electrolyte may improve, there may be a deterioration in the moisture stability of the solid electrolyte or the electrochemical properties of the battery.

[0088] In the above chemical formula 1, a can be 0.005 ≤ a ≤ 0.6, and more specifically, 0.03 ≤ a ≤ 0.35. a can increase or decrease in a proportional manner depending on the increase or decrease in the amount of Li2O added among the oxygen raw materials. If a is too small, the effect of improving moisture stability due to oxygen doping may be negligible. If a is too large, excessive deformation of the basic azirodite crystal structure may occur, which may lead to deterioration of ionic conductivity.

[0089] In the above chemical formula 1, b may be 0.005 ≤ b ≤ 0.04, and more specifically, 0.008 ≤ b ≤ 0.02. b may increase or decrease in a proportional manner depending on the increase or decrease in the amount of P2O5 input among the oxygen raw materials. If b is too small, the effect of improving moisture stability due to oxygen doping may be negligible. If b is too large, excessive deformation of the basic azirodite crystal structure may occur, and the ionic conductivity may deteriorate.

[0090]

[0091] The lithium ion conductive compound according to the present invention is doped with oxygen in an appropriate amount within a range where the ion conductivity is not significantly degraded, so that the ion conductivity at 25°C may be 0.7 mS / cm or higher, and more specifically, 1.1 mS / cm or higher.

[0092] In addition, as the lithium ion conductive compound according to the present invention is doped with oxygen, its moisture stability is improved, and its moisture stability may be 80% or higher. In the present specification, the moisture stability of the solid electrolyte can be determined by calculating the percentage value of the ionic conductivity of the solid electrolyte after exposure to the atmosphere relative to the ionic conductivity of the solid electrolyte before exposure to the atmosphere. The ionic conductivity of the solid electrolyte before exposure to the atmosphere is the ionic conductivity measured at 25°C immediately after synthesizing the solid electrolyte. The ionic conductivity of the solid electrolyte after exposure to the atmosphere is the ionic conductivity measured at 25°C of the recovered solid electrolyte after applying 0.5g of the solid electrolyte in powder form to a watch glass and leaving it for about 8 hours in a dry room with a dew point of about -45°C.

[0093]

[0094] 2. Method for manufacturing solid electrolyte

[0095] Another embodiment of the present invention comprises the steps of: forming a mixture by grinding and mixing a lithium raw material, a phosphorus raw material, a halogen element raw material, and an oxygen raw material; and heat-treating the mixture to form a sulfide-based lithium ion conductive compound having an argyrodite-based crystal structure, wherein the oxygen raw material is Li2O, P2O5, and Li2SO -4 A method for manufacturing a solid electrolyte including is provided.

[0096] Hereinafter, a method for manufacturing a solid electrolyte according to another embodiment of the present invention will be described in detail step by step.

[0097]

[0098] First, lithium raw material, phosphorus raw material, halogen element raw material, and oxygen raw material are ground and mixed using a table mill to form a mixture.

[0099] At this time, the oxygen source materials are Li2O, P2O5, and Li2SO -4 It includes, as oxygen source materials, Li2O, P2O5, and Li2SO -4 By using a combination of these materials, the structural stabilization effect is preferably realized compared to the use of each material alone, and moisture stability can be more preferably realized.

[0100] In addition, by using Li2O as an oxygen source, Li2O can replace a portion of Li2S as a lithium source, thereby reducing the amount of Li2S used, which is expensive and difficult to handle in the atmosphere.

[0101] In addition, the above grinding and mixing can be performed using a table mill. When the grinding and mixing is performed using a table mill, the entrainment of Li2S in the atmosphere and side reactions can be reduced, and low-temperature calcination is possible. Accordingly, the ionic conductivity and moisture stability of the solid electrolyte can be comprehensively improved, and productivity and economic efficiency can be enhanced.

[0102] A table mill refers to a method of grinding and mixing powder by filling a cylindrical container with a certain amount of balls and material to be ground, and rotating it at a specific speed and time to utilize the falling energy of the balls inside.

[0103] In addition, the grinding and mixing may be performed for 3 to 22 hours. If the grinding and mixing time is too short, sufficient grinding and mixing of the raw materials may not occur, which may lead to a decrease in synthesis efficiency during the subsequent heat treatment process and deterioration of the ionic conductivity and moisture stability of the solid electrolyte. If the grinding and mixing time is too long, the performance improvement effect of the ionic conductivity or moisture stability of the solid electrolyte may be negligible compared to the increase in grinding and mixing time, which may result in reduced process cost efficiency.

[0104] In addition, the grinding and mixing can be performed at a rotational speed of 100 to 500 rpm, specifically at 150 to 450 rpm, and more specifically at 200 to 400 rpm. If the rotational speed is too slow, problems may arise such as insufficient overall mixing of the powder particles or insufficient micronization of the powder particles due to low energy. If the rotational speed is too fast, problems may arise such as the powder particles settling in one place, resulting in insufficient even mixing.

[0105]

[0106]

[0107] Next, optionally as needed, after the step of forming the mixture, the method may further include a step of compressing the mixture to form pellets.

[0108] At this time, the compression can be performed at a pressure of 100 to 500 MPa, specifically 150 to 450 MPa, and more specifically 200 to 400 MPa. If the pressure is too low, a problem may arise where interfacial resistance increases due to insufficient binding between powder particles. On the other hand, if the pressure is too high, the binding between powder particles is already established, so the binding state does not change even if additional pressure is applied, which may cause problems in terms of process efficiency. Therefore, forming pellets at an appropriate pressure is desirable in terms of productivity.

[0109]

[0110] Next, the method includes the step of heat-treating the mixture to form a sulfide-based lithium ion conductive compound with an argyrodite-based crystal structure.

[0111] The above heat treatment can be performed at a temperature of 370 to 480°C. If the heat treatment temperature is too low, the ionic conductivity and moisture stability of the solid electrolyte may deteriorate. If the heat treatment temperature is too high, the moisture stability of the solid electrolyte may deteriorate.

[0112] In particular, the above heat treatment temperature range may be lower than the conventional heat treatment synthesis temperature of azirodite-based crystal structure compounds, which is a result of performing table mill grinding and mixing. The inventors confirmed that the moisture stability and ionic conductivity of the solid electrolyte are uniformly excellent within the above heat treatment temperature range. This implies that the azirodite-based crystal structure is optimally expressed within the above range.

[0113]

[0114] In addition, the method for manufacturing a solid electrolyte according to one embodiment of the present invention can reduce the entrainment of Li2S in the atmosphere and side reactions by performing the grinding and mixing of raw materials using a table mill, and enables low-temperature calcination. Accordingly, the ionic conductivity and moisture stability of the solid electrolyte can be comprehensively improved, and productivity and economic efficiency can be enhanced.

[0115]

[0116] 3. All-solid-state battery

[0117] Another embodiment of the present invention provides an all-solid-state battery comprising: an anode layer; a cathode layer; and a solid electrolyte layer located between the anode layer and the cathode layer, wherein at least one of the anode layer, the cathode layer, and the solid electrolyte layer comprises the aforementioned solid electrolyte.

[0118]

[0119] (Bipolar layer)

[0120] More specifically, the anode layer may include an anode current collector and an anode active material layer disposed on the anode current collector.

[0121] The above-mentioned positive active material layer may further include, for example, a positive active material and, optionally, a solid electrolyte. The solid electrolyte included in the positive active material layer may be the same as or different from the solid electrolyte according to one embodiment of the present invention, and may be the same as or different from the solid electrolyte included in the solid electrolyte layer.

[0122] The cathode active material is a material capable of reversibly absorbing and desorbing lithium ions. The cathode active material may be, for example, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide, but is not necessarily limited to these; any material used as a cathode active material in the relevant technical field is acceptable. The cathode active material may be a single material or a mixture of two or more materials.

[0123] The above lithium transition metal oxide is, for example, Li a A 1-b B b D2(wherein 0.90 ≤ a ≤ 1, and 0 ≤ b ≤ 0.5); Li a E 1-b B b O 2-c D c (In the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B b O 4-c D c (In the above equation, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Co b B c O 2-α F α(In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Co b B c O 2-α F2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c O 2-α F2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2(wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d GeO2(wherein the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a CoGb O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a MnG b O2(in the above equation, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f)Fe2(PO4)3(0 ≤ f ≤ 2); a compound represented by any one of the chemical formulas of LiFePO4. In such a compound, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. A compound having a coating layer added to the surface of such a compound may also be used, and a mixture of the compound described above and a compound having a coating layer added may also be used. The coating layer applied to the surface of such a compound comprises, for example, a coating element compound of an oxide, hydroxide, oxyhydroxide, oxycarbonate, or hydroxycarbonate of a coating element. The compound forming this coating layer is amorphous or crystalline. The coating elements included in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the cathode active material. The coating method is, for example, spray coating or immersion. Since specific coating methods are well understood by those skilled in the art, a detailed explanation will be omitted.

[0124] The positive active material layer may include, for example, a binder. The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited to these, and any binder used in the relevant technical field is acceptable.

[0125] The positive active material layer may include, for example, a conductive material. The conductive material may include, for example, graphite, carbon black, acetylene black, Ketjen black, carbon fiber, metal powder, etc., but is not limited to these, and any material used as a conductive material in the relevant technical field is acceptable.

[0126] The positive active material layer may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids in addition to the positive active material, solid electrolyte, binder, and conductive material described above, for example.

[0127] As fillers, coating agents, dispersants, ion conductivity aids, etc. that may be included in the positive electrode active material layer, known materials generally used in electrodes of all-solid-state secondary batteries can be used.

[0128] The positive current collector may be a plate or foil made of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or alloys thereof. The thickness of the positive current collector may be, for example, 1 µm to 100 µm, 1 µm to 50 µm, 5 µm to 25 µm, or 10 µm to 20 µm.

[0129]

[0130] (Cathode layer)

[0131] More specifically, the above cathode layer may include a cathode current collector and a cathode active material layer disposed on the cathode current collector.

[0132] The above-mentioned cathode active material layer may include, for example, a cathode active material and a binder, and may optionally further include a solid electrolyte as needed.

[0133] The above-mentioned negative electrode active material may include, for example, a carbon-based negative electrode active material, a metal / metallic negative electrode active material, or a combination thereof.

[0134] The carbon-based cathode active material may be amorphous carbon, crystalline carbon, or a mixture or composite thereof. The amorphous carbon may be, for example, carbon black (CB), acetylene black (AB), furnace black (FB), Kettjen black (KB), graphene, etc., but is not necessarily limited to these, and any material classified as amorphous carbon in the relevant technical field is acceptable. Amorphous carbon is carbon that does not have crystallinity or has very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon. The crystalline carbon may be, for example, natural graphite, artificial graphite, or a combination thereof.

[0135] The metal / metallic anode active material comprises one or more selected from the group consisting of lithium (Li), gold (Au), platinum (Pt), indium (In), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), but is not necessarily limited to these, and any metal anode active material or metallic anode active material that forms an alloy or compound with lithium in the relevant technical field is acceptable.

[0136] The binder included in the negative electrode active material layer may be, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited to these, and any binder used in the relevant technical field is acceptable. The binder may be composed of a single binder or a plurality of different binders.

[0137] The cathode active material layer is stabilized on the cathode current collector by including a binder. In addition, cracking of the cathode active material layer is suppressed despite volume changes and / or relative positional changes of the cathode active material layer during the charging and discharging process.

[0138] The negative electrode active material layer may further include additives used in conventional all-solid-state batteries, such as fillers, coating agents, dispersants, ion conductivity aids, etc.

[0139] The all-solid-state battery may further include a second negative electrode active material layer disposed between the negative electrode current collector and the negative electrode active material layer upon charging. The second negative electrode active material layer may be deposited between the negative electrode current collector and the negative electrode current collector during the charging process, or may be further disposed on the negative electrode active material layer during electrode assembly. This second negative electrode active material layer may be a metal layer comprising lithium or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, but is not limited thereto; any alloy used as a lithium alloy in the relevant technical field is acceptable. The second negative electrode active material layer may be composed of one of these alloys and / or lithium, or may be composed of various types of alloys and / or lithium.

[0140] The negative electrode current collector may be composed of, for example, a material that does not react with lithium, that is, does not form either an alloy or a compound. The negative electrode current collector may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but is not necessarily limited to these; any material used as an electrode current collector in the relevant technical field is acceptable. The negative electrode current collector may be composed of one of the metals described above, or may be composed of an alloy or coating material of two or more metals. The negative electrode current collector may be, for example, in the form of a plate or a foil.

[0141] When the above-mentioned cathode active material layer includes a solid electrolyte, the solid electrolyte included in the above-mentioned cathode active material layer may be the same as or different from the solid electrolyte according to one embodiment of the present invention, and may be the same as or different from the solid electrolyte included in the solid electrolyte layer.

[0142]

[0143] (Solid electrolyte layer)

[0144] The above solid electrolyte layer can be manufactured by mixing and drying the aforementioned solid electrolyte and binder, or by rolling the aforementioned solid electrolyte powder into a certain shape under a pressure of 1 ton to 10 ton.

[0145] At this time, the solid electrolyte may be in the form of a powder or a molded article. The solid electrolyte in the form of a molded article may be, for example, in the form of pellets, sheets, thin films, etc., but is not necessarily limited to these and may have various forms depending on the application.

[0146] The above solid electrolyte layer may, if necessary, further include a solid electrolyte such as a conventional sulfide-based solid electrolyte and / or an oxide-based solid electrolyte in addition to the aforementioned solid electrolyte.

[0147] The above binder is, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, etc., but is not limited to these, and any binder used in the relevant technical field is acceptable. The binder of the solid electrolyte layer may be of the same type as or different from the binders of the anode layer and the cathode layer.

[0148]

[0149] Another embodiment of the present invention provides an electric vehicle comprising the all-solid-state battery.

[0150]

[0151] The embodiments of the present invention will be described in more detail below through examples. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited by the following examples.

[0152]

[0153] Example 1: Li 5.9 PS 4.9 O 0.06 Cl 0.98 Manufacturing (table mill)

[0154] (1) Preparation of solid electrolyte

[0155] (Grinding and mixing) The final product is Li7-5a-7b-x(1-ab)P (1-a-b)+2b S (1-a-b)(6-x) O a+5b D (1-a-b)x In a solid electrolyte of composition, reactants Li2S, P2S5, Li2O, P2O5, Li2SO4, and LiCl were added in stoichiometric ratios such that x=1, a=0.01, and b=0.01, and a mixture was formed by grinding and mixing using a table mill at 300 rpm for about 10 hours.

[0156] (Pressure) Next, a pressure of 300 MPa was applied to the above mixture to form pellets.

[0157]

[0158] (Heat treatment) Next, the above pellets were heat-treated at 430°C in an argon (Ar) atmosphere to produce a solid electrolyte.

[0159] (2) Manufacturing of solid-state batteries

[0160] The solid electrolyte prepared above is used as the electrolyte, and Li1Ni is used as the positive electrode active material. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery was manufactured using O2 and an In-Li alloy as the negative electrode active material.

[0161]

[0162]

[0163] Comparative Example 1: Preparation of Li6PS5Cl solid electrolyte (Planetary Mill)

[0164] (Grinding and mixing) The reactants Li2S, P2S5, and LiCl were ground and mixed using a planetary mill at 300 rpm for about 10 hours to form a mixture.

[0165] (Pressure) Next, a pressure of 300 MPa was applied to the above mixture to form pellets.

[0166] (Heat treatment) Next, the above pellets were heat-treated at 430°C in an argon (Ar) atmosphere to produce a Li6PS5Cl solid electrolyte.

[0167] Subsequently, an all-solid-state battery was manufactured using the same method as in Example 1.

[0168]

[0169] Comparative Example 2: Preparation of Li6PS5Cl solid electrolyte (Planetary Mill)

[0170] A solid electrolyte and an all-solid-state battery were manufactured in the same manner as Comparative Example 1, except that the heat treatment step was performed at 500°C.

[0171]

[0172] Other examples, comparative examples, and reference examples

[0173] A solid electrolyte and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the amount of raw materials input was varied with compositions having different x, a, and b values ​​as shown in Table 1 below during the grinding and mixing step, the grinding and mixing time was varied, and the heat treatment time was varied during the heat treatment step.

[0174] (Hereafter, Example 2 is duplicated in Tables 1 to 4 to facilitate the review of results based on process control.)

[0175]

[0176] Composition Process xab Grinding and Mixing Method Stirring Speed ​​(rpm) Grinding and Mixing Time (h) Heat Treatment Temperature (°C) Comparative Example 1 100 Planetary Mill 300 10430 Comparative Example 2 100 Planetary Mill 300 10500 Reference Example 1 10.0 10.01 Planetary Mill 300 10430 Example 1 10.0 10.01 Table Mill 300 10430 Example 2 10.0 50.01 Table Mill 300 10430 Example 3 10.1 0.01 Table Mill 300 10430 Example 4 10.2 0.01 Table Mill 300 10430 Example 5 10.5 0.01 Table Mill 300 10430 Comparative Example 3 10.7 0.01 Table Mill 300 10430 Example 61.60.010.01 Table Mill 30010430 Example 7 7 7 7 8 8 9 9 9 1 9 1 8 9 1 8 1 1 8 1 1 1 1 1 1 1 1 1 1 1 1 3 12 10.050.01 Table Mill 300 10470 Reference Example 4 10.050.01 Table Mill 300 10520 Reference Example 5 10.050.01 Table Mill 300 10550 Reference Example 6 10.050.01 Table Mill 300 1430 Reference Example 7 10.050.01 Table Mill 300 2430 Example 13 10.050.01 Table Mill 300 5430 Example 2 10.050.01 Table Mill 300 10430 Example 14 10.050.01 Table Mill 300 20430 Reference Example 8 10.050.01 Table Mill 300 50430 Reference Example 9 10.050.01 Table Mill 300 70430 Reference Example 1010.050.01Tablemill300100430

[0177] Tables 2 and 3 below show the final solid electrolyte compositions of the examples, comparative examples, and reference examples in more detail.

[0178] Solid electrolyte composition xabLiPSOCl Comparative Example 1 100 6.000 1.000 5.0000.000 1.000 Comparative Example 2 100 6.000 1.000 5.0000.000 1.000 Reference Example 1 10.010.015.900 1.000 4.9000.0600.980 Example 1 10.010.015.900 1.000 4.9000.0600.980 Example 2 10.05 0.015.74 00.96 04.70 0.10 0.940 Example 3 10.10.015.54 00.91 04.45 00.15 00.890 Example 410.20.015.1400.8103.9500.2500.790 Example 510.50.013.9400.5102.4500.5500.490 Comparative Example 310.70.013.1400.3101.4500.7500.290 Example 61.60.010.015.3121.0004.3120.0601.568 Example 71.60.050.015.1760.9604.1360.1001.504 Example 81.60.10.015.0060.9103.9160.1501.424 Example 91.60.20.014.6660.8103.4760.2501.264 Example 101.60.50.013.6460.5102.1560.5500.784 Reference Example 210.050.015.7400.9604.7000.1000.940 Reference Example 310.050.015.7400.9604.7000.1000.940 Example 1110.050.015.7400.9604.7000.1000.940 Example 210.050.015.7400.9604.7000.1000.940 Example 1210.050.015.7400.9604.7000.1000.940 Reference Example 410.050.015.7400.9604.7000.1000.940 Reference Example 510.050.015.7400.9604.7000.1000.940 Reference Example 610.050.015.7400.9604.7000.1000.940 Reference Example 710.050.015.7400.9604.7000.1000.940 Example 1310.050.015.7400.9604.7000.1000.940 Example 210.050.015.7400.9604.7000.1000.940 Example 1410.050.015.7400.9604.7000.1000.940Reference Example 810.050.015.7400.9604.7000.1000.940Reference Example 910.050.015.7400.9604.7000.1000.940Reference Example 1010.050.015.7400.9604.7000.1000.940.

[0179] Molar ratio between elements in solid electrolyte [Li] / [P][S] / [P][O] / [P][D] / [P][S]+[D] / [P][O] / [Li]+[P]+[S][O] / [Li]+[P]+[S]+[D] Comparative Example 16.0005.0000.0001.0006.0000.0000.000 Comparative Example 26.0005.0000.0001.0006.0000.000.000 Reference Example 15.9004.9000.0600.9805.8800.0050.005 Example 15.9004.9000.0600.9805.8800.0050.005 Example Example 36.0884.8960.1040.9795.8750.0090.008 Example 46.3464.8770.3090.9755.8520.0250.023 Example 57.7254.8041.0780.9615.7650.0800.074 Comparative Example 310.1294.6772.4190.9355.6130.1530.145 Example 65.3124.3120.0601.5685.8800.0060.005 Example 75.3924.3080.1041.5675.8750.0100.008 Example 85.5014.3030.1651.5655.8680.0150.013 Example 95.7604.2910.3091.5605.8520.0280.024 Example 107.1494.2271.0781.5375.7650.0870.078 Reference Example 25.9794.8960.1040.9795.8750.0090.008 Reference Example 35.9794.8960.1040.9795.8750.0090.008 Example 115.9794.8960.1040.9795.8750.0090.008 Example 25.9794.8960.1040.9795.8750.0090.008 Example 125.9794.8960.1040.9795.8750.0090.008 Reference Example 45.9794.8960.1040.9795.8750.0090.008 Reference Example 55.9794.8960.1040.9795.8750.0090.008 Reference Example 65.9794.8960.1040.9795.8750.0090.008 Reference Example 75.9794.8960.1040.9795.8750.0090.008 Example 135.9794.8960.1040.9795.8750.0090.008 Example 25.9794.8960.1040.9795.8750.0090.008 Example 145.9794.8960.1040.9795.8750.0090.008 Reference Example 85.9794.8960.1040.9795.8750.0090.008 Reference Example 95.9794.8960.1040.9795.8750.0090.008 Reference Example 105.9794.8960.1040.9795.8750.0090.008.

[0180] Table 4 below summarizes the results of the evaluation of solid electrolyte properties and all-solid-state battery electrochemical characteristics described below.

[0181] Solid Electrolyte All-Solid State Battery Ion Conductivity Moisture Stability (%) Initial Discharge Capacity Comparative Example 12.1 168 195.1 Comparative Example 22.6 37 120 2.9 Reference Example 12.35 75 20 4.6 Example 12.1 28 120 6.5 Example 21.8 88 5210.5 Example 31.7 18 7210.9 Example 41.1 88 820 1.6 Example 50.7 59 19 1.5 Comparative Example 30.3 58 418 3.6 Example 65.5 47 319 8.8 Example 74.5 18 7210.5 Example 84.1 38 820 8.1 Example 93.8 49 20 6.8 Example 101.3679189.6 Reference Example 21.6376190.6 Reference Example 31.7179201.5 Example 111.882209.8 Example 21.8885210.5 Example 121.9182209.8 Reference Example 42.0479206.1 Reference Example 52.4376201.6 Reference Example 61.1571201.1 Reference Example 71.3578204.3 Example 131.6183205.9 Example 21.8885210.5 Example 142.1786211.5 Reference Example 82.2186210.5 Reference Example 92.2886209.9 Reference Example 102.3187210.4

[0182] Experimental Example 1: Evaluation of Solid Electrolyte Ionic Conductivity and Moisture Stability

[0183] Experiments evaluating the ionic conductivity and atmospheric stability of solid electrolytes prepared according to the examples, comparative examples, and reference examples were conducted, and the results are shown in Table 4 above. The specific experimental methods are as follows.

[0184] (1) Evaluation of ion conductivity (before atmospheric exposure) (25℃, 0.1C)

[0185] After grinding the manufactured solid electrolyte, it was formed into pellets under a pressure of 300 MPa. Then, a cell was fabricated using SUS as the working electrode under a pressure of 70 MPa. After that, the impedance was measured by applying a voltage of 10 mV at 25°C.

[0186] (2) Moisture stability evaluation

[0187] 1) Evaluation of ion conductivity after atmospheric exposure

[0188] In a dry room with a dew point of about -45℃, 0.5g of a solid electrolyte in powder form was applied to a watch glass and left for about 8 hours, after which it was recovered and the impedance was remeasured in the same way as above.

[0189] 2) Moisture stability evaluation

[0190] Moisture stability was evaluated by converting the ion conductivity after atmospheric exposure relative to the ion conductivity (before atmospheric exposure) derived above into a percentage (%).

[0191]

[0192] Experimental Example 2: Evaluation of Initial Discharge Capacity of All-Solid State Battery

[0193] Electrochemical characteristic evaluation experiments were conducted on all-solid-state batteries prepared according to the examples, comparative examples, and reference examples, and the results are shown in Table 4 above. The specific experimental methods are as follows.

[0194] The charging was performed at room temperature (25℃) at 0.1C to 4.25V (vs. Li+ / Li), and the charging current was terminated by setting the current amount to 0.02C at that voltage. After discharging to 2.50V (vs. Li+ / Li) at 0.1C under the same conditions, the charging capacity, discharging capacity, and initial efficiency were evaluated.

[0195]

[0196] Referring to Tables 1 to 4, in the case of Examples 1 to 14 satisfying the solid electrolyte composition according to the present invention (i.e., an oxygen-doped azirodite solid electrolyte composition in which the ([S]+[D]) / [P] value, [O] / ([Li]+[P]+[S]+[D]) value, [O] / ([Li]+[P]+[S]) value, x value, a value, and b value satisfy the range according to the present invention) and process conditions (i.e., conditions in which the table mill grinding mixing method, grinding mixing time, and heat treatment temperature satisfy the range according to the present invention), it was confirmed that moisture stability was improved compared to Comparative Example 1 or Comparative Example 2, which is the basic azirodite composition, while ion conductivity was well realized without significant degradation.

[0197] On the other hand, Comparative Examples 1 and 2 had a basic azirodite composition and were not oxygen-doped, so it was confirmed that the moisture stability was significantly deteriorated compared to the examples.

[0198] In the case of Reference Example 1, even though the composition according to the present invention was satisfied, it was confirmed that the moisture stability was somewhat deteriorated when performed with a planetary mill.

[0199] In the case of Comparative Example 3, it was confirmed that the ion conductivity deteriorated too much as a result of excessive oxygen doping, which did not satisfy the composition according to the present invention.

[0200] In the case of Reference Examples 2 and 3, as a result of the heat treatment temperature being too low, it was confirmed that the ion conductivity and moisture stability deteriorated compared to Example 2, which has the same composition.

[0201] In the case of Reference Examples 4 and 5, it was confirmed that the moisture stability deteriorated compared to Example 2, which has the same composition, as a result of the heat treatment temperature being too high.

[0202] In the case of Reference Examples 6 and 7, it was confirmed that the ion conductivity and moisture stability deteriorated compared to Example 2, which had the same composition, as a result of the grinding and mixing time being too short.

[0203] In the case of Reference Examples 8 to 10, as a result of the grinding and mixing time being too long, it was confirmed that although the ion conductivity or moisture stability was improved compared to Example 2, which had the same composition, the extent of improvement was significantly small. Therefore, it was evident that the reduction in process cost efficiency in Reference Examples 8 to 10 was predictable.

[0204]

[0205] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

[0206] Therefore, the substantive scope of the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A sulfide-based lithium ion conductive compound containing lithium (Li), phosphorus (P), sulfur (S), a halogen element (D), and oxygen (O), and having an argyrodite-based crystal structure, and The above lithium ion conductive compound is a solid electrolyte satisfying Formula 1 below: [Equation 1] 5.7≤([S]+[D]) / [P]≤5.9 In the above Equation 1, [S] is the mole fraction of sulfur in the lithium ion conductive compound, [D] is the mole fraction of a halogen element in the lithium ion conductive compound, and [P] is the mole fraction of phosphorus in the lithium ion conductive compound.

2. In Paragraph 1, The above lithium ion conductive compound is a solid electrolyte satisfying Formula 2 below: [Equation 2] 0.004≤[O] / ([Li]+[P]+[S]+[D])≤0.1 In the above Equation 2, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, [S] is the mole fraction of sulfur in the lithium ion conductive compound, and [D] is the mole fraction of a halogen element in the lithium ion conductive compound.

3. In Paragraph 1, The above lithium ion conductive compound is a solid electrolyte satisfying Formula 3 below: [Equation 3] 0.004≤[O] / ([Li]+[P]+[S])≤0.12 In the above Equation 3, [O] is the mole fraction of oxygen in the lithium ion conductive compound, [Li] is the mole fraction of lithium in the lithium ion conductive compound, [P] is the mole fraction of phosphorus in the lithium ion conductive compound, and [S] is the mole fraction of sulfur in the lithium ion conductive compound.

4. In Paragraph 1, The above lithium ion conductive compound is a solid electrolyte represented by the following chemical formula 1: [Chemical Formula 1] Li7-5a-7b-x(1-ab)P (1-a-b)+2b S (1-a-b)(6-x) O a+5b D (1-a-b)x In the above chemical formula 1, D is a halogen element such as F, Cl, Br, I, or a combination thereof, 1≤x≤2, 0.005≤a≤0.6, and 0.005≤b≤0.

04.

5. A step of forming a mixture by grinding and mixing a lithium raw material, a phosphorus raw material, a halogen element raw material, and an oxygen raw material; and The method includes the step of heat-treating the above mixture to form a sulfide-based lithium ion conductive compound having an argyrodite-based crystal structure, and The above oxygen source materials are Li2O, P2O5, and Li2SO -4 A method for manufacturing a solid electrolyte comprising 6. In Paragraph 5, The above grinding and mixing is a method for manufacturing a solid electrolyte performed using a table mill.

7. In Paragraph 5, A method for manufacturing a solid electrolyte in which the above grinding and mixing is performed for 3 to 22 hours.

8. In Paragraph 5, A method for manufacturing a solid electrolyte in which the above heat treatment is performed at a temperature of 370 to 480°C.

9. An anode layer; a cathode layer and a solid electrolyte layer located between the anode layer and the cathode layer, and An all-solid-state battery in which at least one of the anode layer, cathode layer, and solid electrolyte layer comprises the solid electrolyte of claim 1.