Solid electrolyte, preparation method therefor, and all-solid-state battery comprising same

Abstract

The present invention relates to a sulfide-based solid electrolyte, a preparation method therefor, and an all-solid-state battery comprising same, the sulfide-based solid electrolyte comprising a compound which contains lithium (Li), phosphorus (P), sulfur (S), and chlorine (Cl), and which has an argyrodite-based crystal structure, wherein at least a portion of the crystal structure is doped with boron (B), a group 14 element (α), and oxygen (O), and the molar ratio of boron (B) and the group 14 element (α) to oxygen (O) (([B]+[α]) / [O]) in the doped material is 0.7 to 1.6.

Description

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

[0001] The present invention relates to a solid electrolyte, a method for manufacturing the same, and an all-solid-state battery comprising the same.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0191842, filed on December 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] Recently, the demand for high-performance batteries has been rapidly increasing in application fields such as IT mobile devices, small power drive systems (e-bikes, small EVs, etc.), and energy storage systems (ESS). Due to this growing demand, higher capacity and output power of energy storage devices are becoming essential, and ensuring safety and reliability has emerged as a critical issue. While conventional lithium-ion rechargeable batteries have been commercialized based on their high energy density and excellent cycle life, there are limitations in ensuring safety due to issues such as the flammability of liquid electrolytes and thermal runaway caused by internal short circuits.

[0004] To address these issues, all-solid-state batteries are attracting attention as promising next-generation energy storage devices. By replacing liquid electrolytes with solid electrolytes, all-solid-state batteries offer high safety and stability while possessing the potential to maximize energy density. In particular, solid electrolytes have high electrochemical stability and can be combined with lithium metal anodes, offering the advantage of theoretically enabling higher capacity and energy density.

[0005] Among solid electrolytes, Li6PS5Cl-based sulfide-based solid electrolytes having an argyrodite structure have excellent ionic conductivity (10 -3 ~ 10 -2It is evaluated as a candidate material with high commercialization potential due to its relatively low synthesis temperature and simplified manufacturing process, along with its S / cm level. Such electrolytes support the rapid movement of lithium ions and exhibit characteristics favorable for improving interfacial stability with electrodes. Accordingly, active research and development on Li6PS5Cl and its modified compositions is being conducted by various research groups.

[0006] However, sulfide-based solid electrolytes are sensitive to moisture, posing a problem of causing side reactions that generate toxic gases such as H2S under normal atmospheric conditions. This characteristic necessitates strict environmental control during manufacturing and handling processes, acting as a major constraint on commercialization. Therefore, research into compositional modifications to improve the moisture stability of sulfide-based solid electrolytes, the development of surface coating technologies, and manufacturing processes that optimize environmental conditions are emerging as critical tasks.

[0007] The objective of the present invention is to solve the problems of the aforementioned prior art by providing a sulfide-based solid electrolyte with excellent moisture stability without degradation of ion conductivity and battery cell performance, a method for manufacturing the same, and an all-solid-state battery including the same.

[0008] A sulfide-based solid electrolyte according to one embodiment of the present invention comprises a compound having an argyrodite-based crystal structure containing lithium (Li), phosphorus (P), sulfur (S), and chlorine (Cl), wherein at least a portion of the crystal structure is doped with boron (B), a group 14 element (α), and oxygen (O), and the molar ratio of the boron (B) and the group 14 element (α) to oxygen (O) in the doped material (([B]+[α]) / [O]) is 0.7 to 1.6, and the ion conductivity retention rate measured after exposure to an atmosphere with a dew point of -40 °C for 8 hours may be 40.0% or higher.

[0009] Group 14 element (α) may be silicon (Si), germanium (Ge), tin (Sn), or a combination thereof.

[0010] The molar ratio of boron (B) to oxygen (O) in the doped material ([B] / [O]) may be 0.6 to 0.7.

[0011] A sulfide-based solid electrolyte according to one embodiment may have an ion conductivity retention rate of 40.0% measured after exposure to an atmosphere with a dew point of -40°C for 8 hours.

[0012] The compound can be represented by the following chemical formula 1.

[0013] [Chemical Formula 1]

[0014] Li 6(1-x-y) B 2x A y P (1-x-y) S 5(1-x-y) O 3x Cl(1-xy)+4y

[0015] In Chemical Formula 1, A is a Group 14 element (α).

[0016] 0.03 ≤ x ≤ 0.07 may be possible.

[0017] 0.015 ≤ y ≤ 0.055 may be possible.

[0018] A method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention comprises the steps of: mixing a lithium (Li) raw material, a phosphorus (P) raw material, a chlorine (Cl) raw material, and a doping raw material to form a mixture; and heat-treating the mixture to form a sulfide-based solid electrolyte having an argyrodite-based crystal structure, wherein the doping raw material includes a boron (B) compound and a tin (Sn) compound, and the boron (B) compound may contain oxygen (O).

[0019] The boron (B) compound can be B2O3.

[0020] Tin (Sn) compounds are SnCl4, SnCl2, and SnS 2, It may be SnS, SnO2, SnO, or a combination thereof.

[0021] The amount of boron (B) compound added may be 0.03 to 0.07 mol% based on the total moles of the mixture.

[0022] The amount of tin (Sn) compound added may be 0.015 to 0.055 mol% based on the total moles of the mixture.

[0023] A solid-state battery according to another embodiment of the present invention comprises a positive electrode layer; a negative electrode layer; and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, wherein at least one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer may comprise the aforementioned solid electrolyte.

[0024] A sulfide-based solid electrolyte according to one embodiment of the present invention can improve moisture stability without deterioration of ion conductivity and battery cell performance.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Also, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

[0030] 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.

[0031] 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.

[0032]

[0033] 1. Solid electrolyte

[0034] A sulfide-based solid electrolyte according to one embodiment of the present invention may include a compound having an argyrodite-based crystal structure containing lithium (Li), phosphorus (P), sulfur (S), and chlorine (Cl). Specifically, the compound may be Li6PS5Cl.

[0035] In this case, the sulfide-based solid electrolyte according to one embodiment of the present invention may have at least a portion of the azirodite-based crystal structure doped with boron (B), a group 14 element (α), and oxygen (O).

[0036] By doping a sulfide-based solid electrolyte with an azirodite crystal structure with boron (B) and a Group 14 element (α), the lithium ion concentration is optimized, the mobile pathways for lithium ions are increased, and the interaction between anions and lithium ions is weakened, thereby improving ionic conductivity. Additionally, defects within the crystal structure are controlled, the activation energy of lithium ion movement is lowered, and structural flexibility is provided to maximize the mobility of lithium ions. Furthermore, intergranular connectivity is improved and interfacial resistance is reduced, thereby improving overall conductivity performance. In other words, by doping a sulfide-based solid electrolyte with an azirodite crystal structure with boron (B) and a Group 14 element (α), the ionic conductivity of the electrolyte can be improved due to the aforementioned structural and electrochemical changes.

[0037] By doping oxygen (O) into an azirodite-based sulfide solid electrolyte, reactivity with water is reduced due to the strong electronegativity and bonding strength of oxygen (O), and chemical stability is increased as oxygen (O) is introduced instead of sulfur (S). Furthermore, the crystal structure is made denser and stronger to inhibit the penetration of water molecules and reduce defect formation, thereby lowering reactivity with moisture. Additionally, surface chemical properties are altered to lower the affinity for water and improve the long-term stability and durability of the electrolyte. In other words, by doping oxygen (O) into a sulfide-based solid electrolyte with an azirodite crystal structure, the moisture stability of the electrolyte is improved through the aforementioned methods, which can also improve handling performance and lifespan.

[0038] The molar ratio of boron (B) and group 14 element (α) to oxygen (O) in the doped material (([B]+[α]) / [O]) may be 0.7 to 1.2. Specifically, the molar ratio (([B]+[α]) / [O]) may be 0.75 to 1.2. Specifically, the molar ratio (([B]+[α]) / [O]) may be 0.7 to 1.1. Specifically, the molar ratio (([B]+[α]) / [O]) may be 0.75 to 1.1. If the molar ratio of boron (B) and group 14 element (α) to oxygen (O) (([B]+[α]) / [O]) is too small, the oxygen element becomes relatively more abundant, which may increase water stability but results in a problem where ionic conductivity becomes inferior. In addition, if the molar ratio of boron (B) and group 14 element (α) to oxygen (O) (([B]+[α]) / [O]) is too large, the amount of heterogeneous element doping increases, which may improve ion conductivity, but there is a problem that moisture stability may be inferior due to the low oxygen content.

[0039] The Group 14 element (α) may be silicon (Si), germanium (Ge), tin (Sn), or a combination thereof. Specifically, the Group 14 element (α) may be tin (Sn).

[0040] When silicon (Si) is doped into azirodite-based sulfide solid electrolytes, structural stability is enhanced through strong Si-S bonding, and moisture stability is improved by reducing reactivity with water. Additionally, ionic conductivity is increased by optimizing lithium ion migration pathways, and compatibility with high-voltage electrodes is improved due to enhanced oxidation stability.

[0041] When germanium (Ge) is doped into an azirodite-based sulfide solid electrolyte, [GeS4] 4- It forms units to significantly expand the lithium ion transport pathway, providing excellent ionic conductivity; enhances crystal structure stability by maintaining structural symmetry and controlling defects; and improves ionic conductivity by increasing interfacial stability and reducing activation energy.

[0042] When tin (Sn) is doped into azirodite-based sulfide solid electrolytes, it provides cost-effectiveness while increasing mechanical flexibility, improves compatibility with high-voltage anodes through high oxidation stability, and enhances long-term stability through increased ionic conductivity and suppression of interfacial reactions.

[0043] The molar ratio of boron (B) to oxygen (O) in the doped material ([B] / [O]) may be 0.6 to 0.7. If the molar ratio of boron (B) to oxygen (O) in the doped material ([B] / [O]) is too small, the improvement in ionic conductivity is inferior, and if the molar ratio of boron (B) to oxygen (O) in the doped material ([B] / [O]) is too large, the improvement in moisture stability is inferior.

[0044] According to one embodiment, a sulfide-based solid electrolyte may have an ion conductivity retention rate of 40.0% or higher when measured after exposure to a dry room with a dew point of -40°C for 8 hours based on a daily working time. Specifically, the ion conductivity retention rate may be 42.0% or higher. A low ion conductivity retention rate of a sulfide-based solid electrolyte after exposure to moisture implies that adverse reactions with moisture occur readily. If the ion conductivity retention rate of a sulfide-based solid electrolyte after exposure to moisture is too low—that is, if reactions with moisture occur too readily—the lithium ion transport pathway is destroyed due to electrolyte decomposition, conductivity decreases, and battery performance deteriorates. Additionally, H2S gas is generated, worsening the manufacturing environment and interface stability, and decomposition products accumulate at the electrode-electrolyte interface, increasing resistance and shortening battery life. These problems reduce the operational stability and reliability of the all-solid-state battery and result in additional costs and complexity during the manufacturing and storage processes.

[0045] The compound can be represented by the following chemical formula 1.

[0046] [Chemical Formula 1]

[0047] Li 6(1-x-y) B 2x A y P (1-x-y) S 5(1-x-y) O 3x Cl(1-xy)+4y

[0048] In Chemical Formula 1, A is a Group 14 element (α). The types and effects of the doped Group 14 element (α) have been described above and are therefore not repeated.

[0049] In Chemical Formula 1, 2x represents the amount of doping boron (B), the doping element, in moles. In this case, 0.03 ≤ x ≤ 0.07 may be used. Specifically, 0.035 ≤ x ≤ 0.065 may be used. If x is too small, there is a problem that the effect of improving ionic conductivity is negligible, and if x is too large, it exists as an impurity, resulting in an inferior effect on ionic conductivity characteristics.

[0050] In Chemical Formula 1, y represents the doping amount of tin, a doping element, in moles. In this case, 0.015 ≤ y ≤ 0.055 may be the case. Specifically, 0.02 ≤ y ≤ 0.05 may be the case. If y is too small, the tin doping amount is too low, so the aforementioned effect of improving the ionic conductivity of the solid electrolyte may be negligible. If y is too large, the azirodite crystal structure is significantly deformed due to excessive doping, which hinders the smooth movement of lithium ions. Furthermore, tin fails to form an azirodite crystal structure and exists as an impurity, which may actually lower the ionic conductivity of the solid electrolyte. Therefore, the effect of improving the ionic conductivity of the solid electrolyte can be preferably realized when y satisfies the above range.

[0051] Meanwhile, in a sulfide-based solid electrolyte according to one embodiment of the present invention, boron (B) and a Group 14 element (α) can be doped with independent doping amounts. In other words, the moles of the doped boron (B) and the Group 14 element (α) do not have a constant correlation but can be randomly controlled with independent doping amounts. Accordingly, the aforementioned effect of improving the performance of the solid electrolyte or battery can be preferably maximized.

[0052] Sulfide-based solid electrolytes can be in the form of particles or powder, and can be crystalline or amorphous.

[0053]

[0054] 2. Method for manufacturing solid electrolyte

[0055] A method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention comprises the steps of: mixing a lithium (Li) raw material, a phosphorus (P) raw material, a chlorine (Cl) raw material, and a doping raw material to form a mixture; and heat-treating the mixture to form a sulfide-based solid electrolyte having an argyrodite-based crystal structure, wherein the doping raw material may include a boron (B) compound and a tin (Sn) compound, and the boron (B) compound may include both boron (B) and oxygen (O).

[0056] Hereinafter, a method for manufacturing a sulfide-based solid electrolyte according to another embodiment of the present invention will be described step by step.

[0057] First, a lithium (Li) raw material, a phosphorus (P) raw material, a chlorine (Cl) raw material, and a doping raw material are mixed to form a mixture.

[0058] The lithium (Li) source material may be, for example, Li2S, Li2S2, or a combination thereof, but is not necessarily limited thereto. Specifically, the lithium (Li) source material may be Li2S.

[0059] The phosphorus (P) source material may be, for example, P2S5, P2O5, or a combination thereof, but is not necessarily limited thereto. Specifically, the phosphorus (P) source material may be P2S5.

[0060] The chlorine (Cl) source material may be, for example, LiCl, PCl3, PCl5, SCl2, S2Cl2, or a combination thereof, but is not necessarily limited thereto. Specifically, the chlorine (Cl) source material may be LiCl.

[0061] Boron (B) compounds can contain oxygen (O).

[0062] The boron (B) compound is not particularly limited as long as it is a compound containing oxygen (O), and may be, for example, B2O3, Li2B4O7, H3BO3, LiBO2, or a combination thereof. Specifically, the boron (B) compound may be B2O3.

[0063] By using a boron (B) compound containing both boron (B) and oxygen (O) as a doping material, there is an advantage in that boron (B) and oxygen (O) can be provided simultaneously during the reaction process.

[0064] Tin (Sn) compounds are not particularly limited as long as they contain tin (Sn), for example, SnCl4, SnCl2, SnS 2, It may be SnS, SnO2, SnO, or a combination thereof.

[0065] The tin (Sn) compound can be more specifically SnCl4. By using SnCl4 as the tin (Sn) compound, there is an advantage in being able to design a composition rich in chlorine (Cl) content while simultaneously doping with tin (Sn).

[0066] The amount of boron (B) compound added may be 0.03 to 0.07 mol% based on the total molar amount of the mixture, and more specifically, 0.035 to 0.065 mol%. When the amount of boron (B) compound added satisfies the above range, the boron (B) doping amount is doped to the aforementioned range, so that the ionic conductivity of the electrolyte and the electrochemical properties of the battery can be preferably realized.

[0067] The amount of tin (Sn) compound added may be 0.015 to 0.055 mol% based on the total molar amount of the mixture, and more specifically, 0.02 to 0.05 mol%. When the amount of tin (Sn) compound added satisfies the above range, the tin (Sn) doping amount is doped to the aforementioned range, so that the ionic conductivity of the electrolyte and the electrochemical properties of the battery can be preferably realized.

[0068] The mixing of raw materials can be carried out by mechanical mixing or chemical mixing.

[0069] Mechanical mixing can be performed by methods such as a planetary mill, paint shaker, ball mill, bead mill, homogenizer, hammer mill, turbo mill, disc mill, planetary mill, mechanofusion, etc.

[0070] Chemical mixing can be performed, for example, by melt quenching.

[0071] Mixing can be performed for 4 to 12 hours, specifically 6 to 10 hours, and more specifically 7 to 9 hours. If the mixing time is too short, a problem may arise where mixing is insufficient. If the mixing time is too long, mixing may be fully completed after a certain period, and even if mixing is continued, the mixing state will remain the same, which may cause problems in terms of process efficiency.

[0072] 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, the balls may not penetrate into the powder, resulting in less overall mixing of the powder particles or lower energy, which may lead to insufficient atomization of the powder particles. On the other hand, if the rotational speed is too fast, the powder particles may become concentrated in one area, resulting in less even mixing.

[0073] Next, optionally as needed, after the step of forming the mixture, a step of compressing the mixture to form pellets may be further included.

[0074] At this time, 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.

[0075] Next, the mixture is heat-treated to form a sulfide-based solid electrolyte with an argyrodite-based crystal structure.

[0076] At this time, the heat treatment can be performed at a temperature of 400 to 700°C, and more specifically at 500 to 600°C. If the heat treatment temperature is too low, the synthesis of the solid electrolyte with an azirodite crystal structure may not occur sufficiently, or it may be synthesized into an amorphous crystal structure, which may result in a decrease in the ionic conductivity of the solid electrolyte. If the heat treatment temperature is too high, the elements constituting the solid electrolyte may vaporize, causing the solid electrolyte to be lost, or impurity phases may be generated, which may result in a decrease in the ionic conductivity of the solid electrolyte.

[0077] In addition, the heat treatment can be performed for 2 to 8 hours, and more specifically, for 3 to 5 hours. If the heat treatment time is too short, the synthesis of the solid electrolyte with an azirodite crystal structure may not occur sufficiently, or it may be synthesized into an amorphous crystal structure, which may result in a decrease in the ionic conductivity of the solid electrolyte. If the heat treatment time is too long, the elements constituting the solid electrolyte may vaporize, causing the solid electrolyte to be lost, or impurity phases may be generated, which may result in a decrease in the ionic conductivity of the solid electrolyte.

[0078] In addition, the heat treatment may be performed in an inert gas atmosphere. Since the heat treatment is performed in an inert gas atmosphere, there may be an advantage in that contact with atmospheric moisture can be blocked. The inert gas atmosphere may be, for example, an Ar, N2, H2, or He atmosphere, and more specifically, an Ar atmosphere.

[0079]

[0080] 3. All-solid-state battery

[0081] A solid-state battery according to another embodiment of the present invention comprises a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, and at least one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer may comprise the aforementioned solid electrolyte.

[0082]

[0083] (Bipolar layer)

[0084] More specifically, the anode layer may include an anode current collector and an anode active material layer disposed on the anode current collector.

[0085] The 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.

[0086] 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.

[0087] Lithium transition metal oxides are, 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093]

[0094] (Cathode layer)

[0095] More specifically, the cathode layer may include a cathode current collector and a cathode active material layer disposed on the cathode current collector.

[0096] The negative electrode active material layer may include, for example, a negative electrode active material and a binder, and may optionally further include a solid electrolyte as needed.

[0097] The 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.

[0098] 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; 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.

[0099] The metal / metallic anode active material comprises one or more selected from the group consisting of lithium (Li), gold (Au), platinum (Pt), 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] When the negative electrode active material layer includes a solid electrolyte, the solid electrolyte included in the negative electrode 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.

[0106]

[0107] (Solid electrolyte layer)

[0108] The 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 specific shape under a pressure of 1 ton to 10 ton.

[0109] In this case, the solid electrolyte may be in the form of a powder or a molded product. The solid electrolyte in the form of a molded product may be, for example, in the form of pellets, sheets, or thin films, but is not necessarily limited to these and may have various forms depending on the application.

[0110] If necessary, the solid electrolyte layer may 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.

[0111] The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, etc., but is not limited to these; any binder used in the relevant technical field may be used. 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.

[0112]

[0113] An electric vehicle according to another embodiment of the present invention may include the aforementioned all-solid-state battery.

[0114]

[0115] 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.

[0116]

[0117] Preparation Example: Preparation of Li6PS5Cl solid electrolyte

[0118] The reactants Li2S, P2S5, and LiCl were mixed using a planetary mill at 300 rpm for about 8 hours to form a mixture.

[0119] Next, a pressure of 300 MPa was applied to the above mixture to form pellets.

[0120] Next, the above pellets were heat-treated at 550°C for 4 hours in an argon (Ar) atmosphere to prepare a Li6PS5Cl solid electrolyte.

[0121]

[0122] Example 1: Li 5.16 B 0.12 Sn 0.02 P 0.92 S 4.3 O 0.18Cl 1.34 Solid Electrolyte Manufacturing

[0123] The final product is Li 6(1-x-y) B 2x Sn y P (1-x-y) S 5(1-x-y) O 3x In a Cl(1-xy)+4y solid electrolyte, the reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.02, and B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.02 mol% based on 100 mol% of the total reactants, and a mixture was formed by mixing at 300 rpm for about 8 hours using a planetary mill.

[0124] Next, a pressure of 300 MPa was applied to the above mixture to form pellets.

[0125] Next, the above pellets are heat-treated in an argon (Ar) atmosphere at 550°C for approximately 4 X hours to Li 5.16 B 0.12 Sn 0.02 P 0.92 S 4.3 O 0.18 Cl 1.34 A solid electrolyte was manufactured.

[0126]

[0127] Example 2: Li 5.1 B 0.12 Sn 0.03 P 0.91 S 4.25 O 0.18 Cl 1.33 Preparation of solid electrolytes

[0128] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.03, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.03 mol% based on 100 mol% of the total reactants, and Li 5.1 B 0.12 Sn 0.03 P 0.91 S 4.25 O 0.18 Cl 1.33 A solid electrolyte was manufactured.

[0129]

[0130] Example 3: Li 5.04 B 0.12 Sn 0.04 P 0.9 S 4.2 O 0.18 Cl 1.32 Preparation of solid electrolytes

[0131] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.04, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.04 mol% based on 100 mol% of the total reactants, and Li 5.04 B 0.12 Sn 0.04 P 0.9 S 4.2 O 0.18 Cl 1.32 A solid electrolyte was manufactured.

[0132]

[0133] Example 4: Li 5.01 B 0.12 Sn 0.045 P 0.895 S 4.175 O 0.18 Cl 1.315 Preparation of solid electrolytes

[0134] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.6 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li 5.01 B 0.12 Sn 0.045 P 0.895 S 4.175 O 0.18 Cl 1.315 A solid electrolyte was manufactured.

[0135]

[0136] Example 5: Li 4.98 B 0.12 Sn 0.05 P 0.89 S 4.15 O 0.18 Cl 1.31 Preparation of solid electrolytes

[0137] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.05, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.05 mol% based on 100 mol% of the total reactants, and Li 4.98 B 0.12 Sn 0.05 P 0.89 S 4.15 O 0.18 Cl 1.31 A solid electrolyte was manufactured.

[0138]

[0139] Example 6: Li 5.49 B 0.04 Sn 0.045 P 0.935 S 4.575 O 0.06 Cl 1.075 Preparation of solid electrolytes

[0140] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.02 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.02 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants. 5.49 B 0.04 Sn 0.045 P 0.935 S 4.575 O 0.06 Cl 1.075 A solid electrolyte was manufactured.

[0141]

[0142] Example 7: Li 5.25 B 0.08 Sn 0.045 P 0.915 S 4.375 O 0.12 Cl 1.195 Preparation of solid electrolytes

[0143] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.04 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.04 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li 5.25 B 0.08 Sn 0.045 P 0.915 S 4.375 O 0.12 Cl 1.195 A solid electrolyte was manufactured.

[0144]

[0145] Example 8: Li 5.13 B 0.1 Sn 0.045 P 0.905 S 4.275 O 0.15 Cl 1.255 Preparation of solid electrolytes

[0146] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.05 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.05 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, thereby Li 5.13 B 0.1 Sn 0.045 P 0.905 S 4.275 O 0.15 Cl 1.255 A solid electrolyte was manufactured.

[0147]

[0148] Example 9: Li 4.89 B 0.14 Sn 0.045 P 0.885 S 4.075 O 0.21 Cl 1.375 Preparation of solid electrolytes

[0149] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.07 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.07 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li 4.89 B 0.14 Sn 0.045 P 0.885 S 4.075 O 0.21 Cl 1.375 A solid electrolyte was manufactured.

[0150]

[0151] Comparative Example 1: Li 4.56 B 0.24 P 0.88 S 3.8 O 0.36 Cl 1.72 Preparation of solid electrolytes

[0152] The reactants Li2S, P2S5, LiCl, and B2O3 were quantified so that x=0.12 and y=0, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.12 mol% based on 100 mol% of the total reactants, and Li 4.56 B 0.24 P 0.88 S 3.8 O 0.36 Cl 1.72 A solid electrolyte was manufactured.

[0153]

[0154] Comparative Example 2: Li 5.73 Sn 0.045 P 0.955 S 4.775 Cl 0.955 Preparation of solid electrolytes

[0155] The reactants Li2S, P2S5, LiCl, and SnCl4 were quantified so that x=0 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li 5.73 Sn 0.045 P 0.955 S 4.775 Cl 0.955 A solid electrolyte was manufactured.

[0156]

[0157] Comparative Example 3: Li 5.49 B 0.04 Sn 0.045 P 0.935 S 4.575 O 0.06 Cl 1.075 Preparation of solid electrolytes

[0158] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.02 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.02 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li5.49 B 0.04 Sn 0.045 P 0.935 S 4.575 O 0.06 Cl 1.075 A solid electrolyte was manufactured.

[0159]

[0160] Comparative Example 4: Li 5.25 B 0.16 Sn 0.045 P 0.875 S 4.375 O 0.24 Cl 1.055 Preparation of solid electrolytes

[0161] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.08 and y=0.045, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.08 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.045 mol% based on 100 mol% of the total reactants, and Li 5.25 B 0.16 Sn 0.045 P 0.875 S 4.375 O 0.24 Cl 1.055 A solid electrolyte was manufactured.

[0162]

[0163] Comparative Example 5: Li 5.58 B 0.12 Sn 0.01 P 0.930 S 4.65 O 0.18 Cl 0.97 Preparation of solid electrolytes

[0164] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.01, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.01 mol% based on 100 mol% of the total reactants, and Li5.58 B 0.12 Sn 0.01 P 0.930 S 4.65 O 0.18 Cl 0.97 A solid electrolyte was manufactured.

[0165]

[0166] Comparative Example 6: Li 5.28 B 0.12 Sn 0.06 P 0.88 S 4.4 O 0.18 Cl 1.12 Preparation of solid electrolytes

[0167] The reactants Li2S, P2S5, LiCl, B2O3, and SnCl4 were quantified so that x=0.06 and y=0.06, and the procedure was carried out in the same manner as Example 1, except that B2O3 was set to 0.06 mol% based on 100 mol% of the total reactants and SnCl4 was set to 0.06 mol% based on 100 mol% of the total reactants, and Li 5.28 B 0.12 Sn 0.06 P 0.88 S 4.4 O 0.18 Cl 1.12 A solid electrolyte was manufactured.

[0168]

[0169] Table 1 below is a table summarizing the x and y values ​​of the examples and comparative examples in Chemical Formula 1, and Table 2 below is a table summarizing the experimental results according to Experimental Example 1 described later for the solid electrolytes of the manufacturing example, examples, and comparative examples.

[0170]

[0171] XY Manufacturing Example--Comparative Example 10.120 Comparative Example 200.045 Comparative Example 30.020.045 Comparative Example 40.080.045 Comparative Example 50.060.01 Comparative Example 60.060.06 Example 10.060.02 Example 20.060.03 Example 30.060.04 Example 40.060.045 Example 50.040.045 Example 60.050.045

[0172] Li a P b S c Cl d B e Sn f O g Li[a]P[b]S[c]Cl[d]B[e]Sn[f]O[g] Ion Conductivity (mS / cm) Ion Conductivity after Moisture Exposure (-40°C Dew Point @ 8 hours) Ion Conductivity Retention Rate (%) after Moisture Exposure Preparation Example 6 151---2.9 0.5 17.24 Comparative Example 1 5.28 0.8 80 4.4 0.8 80.2 40 0.36 1.2 0.9 75.00 Comparative Example 2 5.73 0.9 55 4.7 75 1.1 35 0.0 45 0 1.4 7 0.5 34.01 Comparative Example 3 5.61 0.9 35 4.6 75 1.1 15 0.0 40.0 45 0.0 62.8 0.8 28.57 Comparative Example 45.250.8754.3751.0550.160.0450.241.20.866.7 Comparative Example 55.580.9304.650.970.120.010.181.9157.9 Comparative Example 65.280.8804.41.120.120.060.181.80.950.0 Example 15.520.9204.610.120.020.182.71.244.44 Example 25.460.9104.551.030.120.030.182.51.560.00 Example 35.40.9004.51.060.120.040. 183.11.961.29 Example 45.370.8954.4751.0750.120.0450.184.32.865.12 Example 55.490.9154.5751.0950.080.0450.123.51.542.86 Example 65.430.9054.5251.0850.10.0450.154.12.560.98

[0173] Experimental Example 1: Analysis of Solid Electrolyte Composition and Evaluation of Ionic Conductivity

[0174] (1) Composition analysis

[0175] The composition of the solid electrolyte was measured using an ICP (Inductively Coupled Plasma Emission Spectrometry) instrument. More specifically, all synthesized solid electrolyte samples were dissolved in HNO3 solvent, diluted with DI water, and the elemental content was measured using an ICP instrument.

[0176] (2) Ionic conductivity evaluation (30℃, 0.1C)

[0177] An experiment to evaluate the ionic conductivity of a solid electrolyte was conducted using a pressure powder cell. Specifically, the synthesized solid electrolyte was ground and then formed into pellets under a pressure of 300 MPa. Subsequently, a cell was fabricated using SUS as the working electrode under a pressure of 70 MPa. Then, the impedance was measured by applying a voltage of 10 mV at 30°C.

[0178] (3) Evaluation of ion conductivity after moisture exposure (-40 ℃ dew point, 8 hours)

[0179] The synthesized solid electrolyte powder was exposed to a dry room with a dew point of -40 ℃ for 8 hours based on a daily working time, then transferred to a glove box with an argon atmosphere that was not open to the atmosphere, and its physical properties were evaluated.

[0180] Referring to Table 2, it was confirmed that the solid electrolytes of Comparative Example 1, in which only boron and oxygen were excessively doped without tin and the molar ratio of boron and tin to oxygen and the ranges of x and y were not properly controlled, and Comparative Example 2, in which only tin was doped without boron and oxygen, actually showed lower ionic conductivity compared to the preparation example, which is a solid electrolyte with a basic azyrodite crystal structure. In addition, it was confirmed that the ionic conductivity retention rate of Comparative Example 2 decreased after exposure to moisture. However, the ionic conductivity retention rate of Comparative Example 1 after exposure to moisture improved significantly compared to the preparation example and the example, which was confirmed to be due to the excessive doping of oxygen.

[0181] In addition, in Comparative Examples 3 to 6, where boron, tin, and oxygen were all doped but the molar ratio of boron and tin to oxygen or the ranges of x and y were not properly controlled, it was confirmed that the ionic conductivity characteristics were degraded compared to the preparation example, or that the improvement in the ionic conductivity retention rate after exposure to moisture was very minimal. Specifically, in the case of Comparative Example 2, boron was not doped, so the ionic conductivity characteristics were degraded compared to the preparation example, and it was confirmed that the improvement in the ionic conductivity retention rate after exposure to moisture was also minimal. In the case of Comparative Example 3, too little B2O3 was added, so no improvement in ionic conductivity characteristics occurred, and because the content of doped oxygen was low, it was confirmed that the improvement in the ionic conductivity retention rate after exposure to moisture was also very small. Furthermore, in the case of Comparative Examples 1 and 4, an excessive amount of B2O3 was added, resulting in a large amount of doped oxygen; while moisture stability was greatly improved, the ionic conductivity characteristics were significantly degraded. In addition, in the case of Comparative Examples 5 and 6, the amount of Sn doping was too low, so it was confirmed that the ion conductivity characteristics were actually inferior compared to the manufacturing example.

[0182] On the other hand, the solid electrolyte of the example in which boron, tin, and oxygen are all doped, and the molar ratio of boron and tin to oxygen and the ranges of x and y are appropriately controlled, showed ionic conductivity that was equivalent to or significantly improved compared to the example of preparation, which is a solid electrolyte with a basic azyrodite crystal structure, and it was confirmed that the ionic conductivity after exposure to moisture was also significantly improved.

[0183]

[0184] Table 3 below is a table summarizing the experimental results according to Experimental Example 2 described below for the solid electrolytes of the manufacturing example, example, and comparative example.

[0185]

[0186] 0.1C Charge Amount (mAh / g) 0.1C Discharge Amount (mAh / g) 1st Efficiency (%) Lifespan Retention Rate (30 cycles @ 30℃) (%) Manufacturing Example 2 15.117 5.58 1.5979 Comparative Example 1 2 17.5168 77.2466 Comparative Example 2 2 18.2165 75.6272 Comparative Example 3 2 16.717 8.58 2.3783 Comparative Example 4 2 0 6.416 1.378 8.1569 Comparative Example 5 2 15.2172 79.9375 Comparative Example 621516576.7472 Example 1 217.4177.581.6582 Example 2 216.4178.582.4984 Example 3 215.7181.183.9685 Example 4 214.7185.286.2692 Example 5 215.7179.583.2285 Example 6 214.6182.384.9587

[0187] Experimental Example 2: Evaluation of Electrochemical Characteristics of Lithium Secondary Battery

[0188] (1) Evaluation of initial discharge capacity

[0189] An experiment to evaluate the initial discharge capacity was conducted when the solid electrolytes prepared according to the manufacturing example, example, and comparative example were applied to a battery. The specific experimental method is as follows.

[0190] Electrochemical evaluations of the solid electrolytes of the comparative and exemplary examples were conducted using a pressure powder cell. The composite anode electrode had an anode : solid electrolyte : conductive material (Denka Black) ratio of 70 : 29 : 1 wt% and a diameter of 0.785 cm 2 Electrodes were fabricated with a loading of 20.0 mg over an area and high-density was applied to 300 MPa. Subsequently, bonding was performed at 50 MPa using an Indium-Lithium counter electrode, and the cells were assembled under the same pressure. After fabrication, charge and discharge tests were conducted after aging at room temperature for 2 hours. Capacity evaluation was performed using 180 mAh / g as the reference capacity, and charge / discharge conditions were set at CC / CV 1.9–3.60 V with a 1 / 20C cut-off. Initial capacity was evaluated under 0.1C charge / 0.1C discharge conditions.

[0191]

[0192] (2) Evaluation of lifespan retention rate (30℃, 30 times)

[0193] After manufacturing the cell in the same manner as described above at the initial discharge capacity (1), the first initial charge and discharge cycle was performed at a rate rate of 0.1C at a temperature of 30°C. Subsequently, a charge and discharge cycle for life evaluation was performed at a rate rate of 0.5C at the same temperature conditions (30°C), and the life retention rate was calculated by comparing the 30th discharge capacity with the initial first discharge capacity.

[0194]

[0195] Referring to Table 3, it was confirmed that the solid electrolytes of Comparative Example 1, in which only boron and oxygen were excessively doped without tin and the molar ratio of boron and tin to oxygen and the ranges of x and y were not properly controlled, and Comparative Example 2, in which only tin was doped without boron and oxygen, actually showed a decrease in initial discharge capacity and life retention rate compared to the preparation example, which is a solid electrolyte with a basic azirodite crystal structure.

[0196] In addition, in the case of Comparative Examples 4 to 6, where boron, tin, and oxygen were all doped but the molar ratio of boron and tin to oxygen or the ranges of x and y were not properly controlled, it was confirmed that the initial discharge capacity and life retention rate were actually reduced compared to the manufacturing example.

[0197] On the other hand, it was confirmed that the solid electrolyte of the example, in which boron, tin, and oxygen are all doped and the molar ratio of boron and tin to oxygen and the ranges of x and y are appropriately controlled, had an initial discharge capacity that was equivalent to or improved compared to the example of preparation, which is a solid electrolyte with a basic azyrodite crystal structure, and that the life retention rate was improved.

[0198]

[0199] 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.

[0200] Therefore, the substantive scope of the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A compound containing lithium (Li), phosphorus (P), sulfur (S), and chlorine (Cl) and having an argyrodite-based crystal structure, At least a portion of the above crystal structure is doped with boron (B), a group 14 element (α), and oxygen (O), and A sulfide-based solid electrolyte in which the molar ratio (([B]+[α]) / [O]) of the boron (B) and the group 14 element (α) to the oxygen (O) in the doped material is 0.7 to 1.

6.

2. In Paragraph 1, The above-mentioned Group 14 element (α) is silicon (Si), germanium (Ge), tin (Sn), or a combination thereof, in a sulfide-based solid electrolyte.

3. In Paragraph 1, A sulfide-based solid electrolyte in which the molar ratio ([B] / [O]) of the boron (B) to the oxygen (O) among the doped materials is 0.6 to 0.

7.

4. In Paragraph 1, A sulfide-based solid electrolyte having an ionic conductivity retention rate of 40.0% or higher measured after exposure to a dew point of -40 ℃ atmosphere for 8 hours.

5. In Paragraph 1, The above compound is a sulfide-based solid electrolyte represented by the following chemical formula 1: [Chemical Formula 1] Li 6(1-x-y) B 2x A y P (1-x-y) S 5(1-x-y) O 3x Cl(1-x-y)+4y In the above chemical formula 1, A is the above Group 14 element (α).

6. In Paragraph 5, Sulfide-based solid electrolyte having 0.03 ≤ x ≤ 0.

07.

7. In Paragraph 5, Sulfide-based solid electrolyte having 0.015 ≤ y ≤ 0.

055.

8. A step of mixing a lithium (Li) raw material, a phosphorus (P) raw material, a chlorine (Cl) raw material, and a doping raw material to form a mixture; and The method includes the step of heat-treating the above mixture to form a sulfide-based solid electrolyte with an argyrodite-based crystal structure, and The above doping raw material includes a boron (B) compound and a tin (Sn) compound, and A method for manufacturing a sulfide-based solid electrolyte in which the above boron (B) compound contains oxygen (O).

9. In Paragraph 8, A method for manufacturing a sulfide-based solid electrolyte, wherein the above boron (B) compound is B2O3.

10. In Paragraph 8, The above tin (Sn) compounds are SnCl4, SnCl2, and SnS 2, A method for manufacturing a sulfide-based solid electrolyte, which is SnS, SnO2, SnO, or a combination thereof.

11. In Paragraph 8, A method for manufacturing a sulfide-based solid electrolyte, wherein the amount of the boron (B) compound added is 0.03 to 0.07 mol% based on the total molar amount of the mixture.

12. In Paragraph 8, A method for manufacturing a sulfide-based solid electrolyte, wherein the amount of the tin (Sn) compound added is 0.015 to 0.055 mol% based on the total molar amount of the mixture.

13. Anode layer; 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 a solid electrolyte according to claim 1.