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

Abstract

Disclosed is a solid electrolyte. The solid electrolyte includes at least one compound selected from compounds represented by chemical formulae 1 to 3: [Chemical formula 1] Li3MO1+xH4-2z; [Chemical formula 2] Li3-yM1-yM'yO1+xH4-2z; and [Chemical formula 3] Li3-2yM1-yM'yO1+xH4-2z, wherein, in chemical formulae 1 to 3, x, y, z, M, M', and H are as defined in the detailed description.

Description

Solid electrolyte, method for producing the same, and all-solid-state secondary battery comprising the same

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

[0002] Lithium-ion batteries have high energy density and are used in a variety of applications, including mobile phones, laptops, electric vehicles, and hybrid electric vehicles. Conventional lithium-ion batteries are composed of flammable organic electrolytes, but these flammable organic electrolytes have the disadvantage of causing battery explosions in the event of a short circuit.

[0003] Solid electrolytes are considered as candidates to replace organic electrolytes due to their non-flammability, excellent thermal stability at high temperatures, large potential windows, simplicity of battery design, and low manufacturing costs. Various solid electrolyte materials exist, including oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, and oxyhalide solid electrolytes. Among these, sulfide solid electrolytes offer many advantages, including high compatibility with lithium metal, high ionic conductivity, and mechanical flexibility. However, sulfide solid electrolytes have a low critical current density, which discharges the battery within a few cycles due to rapid lithium dendrite formation. Furthermore, sulfide solid electrolytes have low stability in air and decompose at certain potentials, degrading battery performance. Research is currently underway to develop oxyhalide solid electrolytes, which have high ionic conductivity, high initial Coulombic efficiency, and mechanical flexibility, as alternatives to the aforementioned sulfide solid electrolytes. Oxyhalide solid electrolytes have an ionic conductivity of approximately 1-3 mS / cm, and a method to improve the ionic conductivity is needed.

[0004] One object of the present invention is to provide a solid electrolyte having improved ionic conductivity by containing metal, oxygen, chalcogenide, etc.

[0005] Another object of the present invention is to provide a method for producing the solid electrolyte.

[0006] Another object of the present invention is to provide an all-solid-state secondary battery having increased safety compared to existing secondary batteries by applying the solid electrolyte.

[0007] To achieve the above object, the present invention provides a solid electrolyte comprising at least one compound selected from compounds represented by the following chemical formulas 1 to 3:

[0008] [Chemical Formula 1]

[0009] Li3MO 1+x H 4-2z

[0010] [Chemical Formula 2]

[0011] Li 3-y M 1-y M' y O 1+x H 4-2z

[0012] [Chemical Formula 3]

[0013] Li 3-2y M 1-y M' y O 1+x H 4-2z

[0014] In the above chemical formula 1, 0≤x≤2, 0≤z≤2, M is one element selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, H is one halogen element selected from the group consisting of Cl, Br, I and F,

[0015] In the above chemical formula 2, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a different element from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, Ti, Si, Zr, W, Mo, Ge and Sn, H is a halogen element selected from the group consisting of Cl, Br, I and F,

[0016] In the above chemical formula 3, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, and H is a halogen element selected from the group consisting of Cl, Br, I, and F.

[0017] In addition, the present invention provides a solid electrolyte comprising at least one compound selected from compounds represented by the following chemical formulae 4 to 6:

[0018] [Chemical Formula 4]

[0019] Li3MCh 1+x H 4-2z

[0020] [Chemical Formula 5]

[0021] Li 3-y M 1-y M' y Ch 1+x H 4-2z

[0022] [Chemical Formula 6]

[0023] Li 3-2y M 1-y M" y Ch 1+x H 4-2z

[0024] In the above chemical formula 4, 0≤x≤2, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, Ch is one chalcogen element selected from the group consisting of S, Se and Te, H is one halogen element selected from the group consisting of Cl, Br, I and F,

[0025] In the above chemical formula 5, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M' is one metal selected from the group consisting of Ti, Si, Zr, W, Mo, Ge, and Sn, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, H is one halogen element selected from the group consisting of Cl, Br, I, and F,

[0026] In the above chemical formula 6, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M" is one selected from the group consisting of P, Ta, Nb, and Sb, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

[0027] In addition, the present invention provides a method for producing a solid electrolyte, comprising a step of using a plurality of starting materials selected from the group consisting of alkali metals, alkali metal halides, alkali metal oxides, alkali metal sulfides, metal oxides, metal sulfides, alkali metal chalcogenides, metal chalcogenides, and metal halides, and mixing the plurality of starting materials, and producing a solid electrolyte of any one of the chemical formulae 1 to 6.

[0028] In addition, the present invention provides an all-solid-state secondary battery including the solid electrolyte; a positive electrode disposed on one surface of the solid electrolyte; and a negative electrode disposed on the other surface of the solid electrolyte.

[0029] According to the present invention, the solid electrolyte of the present invention is an oxyhalide solid electrolyte containing excess oxygen, and can have improved ionic conductivity and electrochemical performance compared to existing electrolytes.

[0030] Figure 1 shows the results of X-ray diffraction (XRD) analysis of Examples 1 to 7.

[0031] Figure 2 shows the XRD analysis results of Examples 8 to 10.

[0032] Figure 3 is a graph showing the ionic conductivity of Examples 1 to 7.

[0033] Figure 4 is a graph showing the ionic conductivity of Examples 8 to 10.

[0034] Figure 5 is a graph showing the ionic conductivity of Examples 11 to 14.

[0035] Figure 6 is a graph showing the ionic conductivity of Examples 15 to 17.

[0036] Figure 7 is a graph showing the ionic conductivity of Examples 18 to 19.

[0037] Figure 8 is a charge / discharge curve of Examples 20 to 23.

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention can be modified in various ways and can take various forms, and thus specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0039] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0040] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0041] Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0042]

[0043] A method for producing a solid electrolyte according to one embodiment of the present invention comprises the step of using a plurality of starting materials selected from the group consisting of alkali metals, alkali metal halides, alkali metal oxides, alkali metal sulfides, metal oxides, metal sulfides, alkali metal chalcogenides, metal chalcogenides, and metal halides, and mixing the plurality of starting materials, and can produce a solid electrolyte of any one compound selected from the following chemical formulae 1 to 6:

[0044] [Chemical Formula 1]

[0045] Li3MO 1+x H 4-2z

[0046] [Chemical Formula 2]

[0047] Li 3-y M 1-y M' y O 1+x H 4-2z

[0048] [Chemical Formula 3]

[0049] Li 3-2y M 1-y M' y O 1+x H 4-2z

[0050] [Chemical Formula 4]

[0051] Li3MCh 1+x H 4-2z

[0052] [Chemical Formula 5]

[0053] Li 3-y M 1-y M' y Ch 1+x H 4-2z

[0054] [Chemical Formula 6]

[0055] Li 3-2y M 1-y M" y Ch 1+x H 4-2z

[0056] In the above chemical formula 1, 0≤x≤2, 0≤z≤2, M is one element selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, H is one halogen element selected from the group consisting of Cl, Br, I and F,

[0057] In the above chemical formula 2, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a different element from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, Ti, Si, Zr, W, Mo, Ge and Sn, H is a halogen element selected from the group consisting of Cl, Br, I and F,

[0058] In the above chemical formula 3, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a metal selected from the group consisting of Y, Sc, In, Sb, Bi and Al, H is a halogen element selected from the group consisting of Cl, Br, I and F,

[0059] In the above chemical formula 4, 0≤x≤2, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, Ch is one chalcogen element selected from the group consisting of S, Se and Te, H is one halogen element selected from the group consisting of Cl, Br, I and F,

[0060] In the above chemical formula 5, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M' is one metal selected from the group consisting of Ti, Si, Zr, W, Mo, Ge, and Sn, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, H is one halogen element selected from the group consisting of Cl, Br, I, and F,

[0061] In the above chemical formula 6, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M" is one selected from the group consisting of P, Ta, Nb, and Sb, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

[0062] The alkali metal halide may include at least one selected from the group consisting of LiCl, NaCl, and KCl, the alkali metal oxide may include at least one selected from the group consisting of Li2O, Na2O, and K2O, and the alkali metal sulfide may include at least one selected from the group consisting of Li2S, Na2S, and K2S, but is not limited thereto.

[0063] The metal oxide may include at least one selected from the group consisting of ZrO2, Nb2O5, Ta2O5, WO3, MoO3, P2O5, SiO2, GeO2, Sb2O3, Sb2O5, SnO2, In2O3, Bi2O3, MoO2, WO2, and Al2O-, and the metal sulfide may include at least one selected from the group consisting of Sc2S3, Y2S3, TiS2, ZrS2, Nb2S5, Ta2S5, WS2, MoS2, P2S5, SiS2, GeS2, Sb2S3, Sb2S5, SnS2, In2S3, Bi2S3, MoS3, WS3, and Al2S3, but is not limited thereto.

[0064] The above-described plurality of starting materials may be ball-milled at about 300 to 100 rpm for 10 to 20 hours to mix the starting materials. For example, the ball-milling may be performed for a total of 15 hours by repeating the cycle of operating the mill at about 600 rpm for 30 minutes and resting for about 15 minutes 29 times.

[0065] After the step of mixing the above-described plurality of starting materials, a step of applying pressure to the solid electrolyte to compress it may be added. The compression may be performed to obtain a solid electrolyte of a desired thickness, and the solid electrolyte may be compressed by applying a pressure of about 30 MPa.

[0066] The above solid electrolyte is LiTaOCl4, LiTaO 1.1 Cl 3.8 , LiTaO 1.2 Cl 3.6 , LiTaO 1.3 Cl 3.4 , LiTaO 1.35 Cl 3.3 , LiTaO 1.4 Cl 3.2 , LiTaO 1.5 Cl3, LiTaO 1.35 Cl 3.2 F 0.1 , LiTaO 1.35 Cl 3.1 F 0.2 , LiTaO 1.35 Cl3F 0.3 , LiZrOCl4, Li 1.5 Ta 0.6 Zr 0.4 OCl4, Li 1.5 Ta 0.5 Zr 0.5 OCl4, Li 1.6 Ta 0.4 Zr 0.6 OCl4, Li 1.6 Zr 0.6 P 0.4 OCl4, Li2Zr 0.6 Mo 0.4 OCl4, Li2Zr0.6 Sb 0.4 OCl4, Li 0.9 Na 0.1 TaO 1.35 Cl 3.3 and Li 0.9 Zn 0.05 TaO 1.35 Cl 3.3 It may include one or more selected from the group consisting of .

[0067]

[0068] A solid electrolyte according to one embodiment of the present invention can be manufactured by the above manufacturing method and can include one or more compounds selected from compounds represented by the following chemical formulas 1 to 3:

[0069] [Chemical Formula 1]

[0070] Li3MO 1+x H 4-2z

[0071] [Chemical Formula 2]

[0072] Li 3-y M 1-y M' y O 1+x H 4-2z

[0073] [Chemical Formula 3]

[0074] Li 3-2y M 1-y M' y O 1+x H 4-2z

[0075] In the above chemical formula 1, 0≤x≤2, 0≤z≤2, M may be one element selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, and Sb, and H may be one halogen element selected from the group consisting of Cl, Br, I, and F. For example, in the above chemical formula 1, M may be Ta or Zr, and H may be Cl.

[0076] In the above chemical formula 2, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a different element from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, Ti, Si, Zr, W, Mo, Ge, and Sn, and H may be a halogen element selected from the group consisting of Cl, Br, I, and F. For example, in the above chemical formula 2, M and M' are each a different element from the group consisting of Ta, Zr, P, Mo, Sb, and Na, and H may be Cl.

[0077] In the above chemical formula 3, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, and H may be one halogen element selected from the group consisting of Cl, Br, I, and F.

[0078] A solid electrolyte according to another embodiment of the present invention can be manufactured by the above manufacturing method and can include one or more compounds selected from compounds represented by the following chemical formulas 4 to 6:

[0079] [Chemical Formula 4]

[0080] Li3MCh 1+x H 4-2z

[0081] [Chemical Formula 5]

[0082] Li 3-y M 1-y M' y Ch 1+x H 4-2z

[0083] [Chemical Formula 6]

[0084] Li 3-2y M 1-y M" y Ch 1+x H 4-2z

[0085] In the above chemical formula 4, 0≤x≤2, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, Ch is one chalcogen element selected from the group consisting of S, Se and Te, H is one halogen element selected from the group consisting of Cl, Br, I and F,

[0086] In the above chemical formula 5, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M' is one metal selected from the group consisting of Ti, Si, Zr, W, Mo, Ge, and Sn, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, H is one halogen element selected from the group consisting of Cl, Br, I, and F,

[0087] In the above chemical formula 6, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M" is one selected from the group consisting of P, Ta, Nb, and Sb, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

[0088]

[0089] An all-solid-state secondary battery according to one embodiment of the present invention may include a solid electrolyte comprising a compound represented by any one of the chemical formulas 1 to 6; a positive electrode disposed on one surface of the solid electrolyte; and a negative electrode disposed on the other surface of the solid electrolyte.

[0090] The above solid electrolyte may be a solid electrolyte manufactured by dispersing a compound represented by the chemical formulas 1 to 6 on one surface of a lithium-argyrodite solid electrolyte and then applying pressure.

[0091] The positive electrode may include a current collector and a positive electrode composite disposed on one surface of the current collector. Specifically, the positive electrode composite may include NCM 811, a compound represented by any one of the chemical formulas 1 to 6, and vapor-grown carbon fiber (VGCF), and the current collector may use stainless steel.

[0092] The above cathode can use Li.

[0093] In one embodiment, the negative electrode may be disposed on a surface where the lithium-argyrodite is formed in the solid electrolyte, and the positive electrode complex may be disposed on a surface where a compound represented by any one of the chemical formulae 1 to 6 is formed.

[0094]

[0095] Hereinafter, to aid understanding of the present invention, examples will be given in detail. However, the following examples are intended only to illustrate the scope of the present invention and are not intended to limit its scope. These examples are provided to more fully explain the present invention to those of average skill in the art.

[0096]

[0097] <Example 1>

[0098] Starting materials LiCl, TaCl5, and Ta2O5 were weighed in a molar ratio of 1:0.5:0.2 (LiTaOCl4). The starting materials were ground for 30 minutes and placed in a ball mill container. Twenty-five zirconia balls were added to the ball mill container. The ball mill container was sealed and placed in a ball milling machine, and the ball milling process was performed at 600 rpm for 15 hours (30 minutes of operation, 15 minutes of rest, and 29 repetitions). After the ball milling process was completed, a solid electrolyte was obtained. The composition of the solid electrolyte is shown in Table 1 below.

[0099]

[0100] <Examples 2 to 7>

[0101] A solid electrolyte was obtained by performing the same method as in Example 1, except that the molar ratio of the starting materials was changed so that the O ratios in Example 1 were 1.1, 1.2, 1.3, 1.35, 1.4, and 1.5, respectively. The composition of the solid electrolyte is shown in Table 1 below.

[0102]

[0103] <Examples 8 to 10>

[0104] In the above Example 5, the F precursor was added to the starting material, and the molar ratio of the starting material was set so that the ratio of F was 0.1, 0.2, and 0.3, respectively, and the same method as in Example 5 was performed to obtain a solid electrolyte. The composition of the solid electrolyte is shown in Table 1 below.

[0105]

[0106] <Example 11>

[0107] A solid electrolyte was obtained by performing the same method as in Example 1, except that ZrCl4 was used instead of TaCl5 in the above Example 1. The composition of the solid electrolyte is shown in Table 1 below.

[0108]

[0109] <Examples 12 to 14>

[0110] In the above Example 1, ZrCl4 was added to the starting material, and the molar ratio of the starting material was set to 0.4, 0.5, and 0.6, respectively, and the same method as in Example 1 was performed to obtain a solid electrolyte. The composition of the solid electrolyte is shown in Table 1 below.

[0111]

[0112] <Example 15>

[0113] In Example 14, P205 was used instead of TaCl5, and the molar ratio of the starting materials was set to 0.4, and the same method as Example 14 was performed to obtain a solid electrolyte. The composition of the solid electrolyte is shown in Table 1 below.

[0114]

[0115] <Example 16>

[0116] In Example 15, MoO3 was used instead of P205, and the molar ratio of the starting materials was set to 0.4, and the same method as Example 14 was performed to obtain a solid electrolyte. The composition of the solid electrolyte is shown in Table 1 below.

[0117]

[0118] <Example 17>

[0119] In Example 15, SbO3 was used instead of P205, and the molar ratio of the starting materials was set to 0.4, and the same method as Example 14 was performed to obtain a solid electrolyte. The composition of the solid electrolyte is shown in Table 1 below.

[0120]

[0121] <Example 18>

[0122] A solid electrolyte was obtained by performing the same method as in Example 5, except that NaCl was included in the starting material in Example 5 and the molar ratio of the starting material was set to be 0.1. The composition of the solid electrolyte is shown in Table 1 below.

[0123]

[0124] <Example 19>

[0125] A solid electrolyte was obtained by performing the same method as in Example 5, except that ZnCl was included in the starting material in Example 5 and the molar ratio of the starting material was set to be 0.05. The composition of the solid electrolyte is shown in Table 1 below.

[0126] Composition ionic conductivity (25 o C)(mS / cm)Example 1LiTaOCl42.51Example 2LiTaO 1.1 Cl 3.8 2.53 Example 3LiTaO 1.2 Cl 3.6 6.09 Example 4LiTaO 1.3 Cl 3.4 6.7 Example 5LiTaO 1.35 Cl 3.3 7.34 Example 6LiTaO 1.4 Cl 3.2 6.06 Example 7LiTaO 1.5 Cl34.33Example 8LiTaO 1.35 Cl 3.2 F 0.1 5.99 Example 9LiTaO 1.35 Cl 3.1 F 0.2 4.38 Example 10LiTaO 1.35 Cl3F 0.3 2.77 Example 11 LiZrOCl40.22 Example 12 Li 1.5 Ta 0.6 Zr 0.4 OCl41.24Example 13Li 1.5 Ta 0.5 Zr 0.5 OCl41.30Example 14Li 1.6 Ta0.4 Zr 0.6 OCl41.28Example 15Li 1.6 Zr 0.6 P 0.4 OCl40.10Example 16Li2Zr 0.6 Mo 0.4 OCl40.15Example 17Li2Zr 0.6 Sb 0.4 OCl40.0012Example 18Li 0.9 Na 0.1 TaO 1.35 Cl 3.3 4.25 Example 19Li 0.9 Zn 0.05 TaO 1.35 Cl 3.3 6.98

[0127] Experimental Example 1

[0128] Figure 1 shows the X-ray diffraction (XRD) analysis results of Examples 1 to 7, and Figure 2 shows the XRD analysis results of Examples 8 to 10. The XRD results were confirmed using an X-ray diffractometer (Rigaku-Ultima (IV)) with a Cu Kα radiation (1.5418 Å) source and a scan speed of 0.02° / s. All of Examples 1 to 10 had a trigonal crystal structure, and no particular impurity peaks were observed. As the F content increased in Examples 8 to 10, the peaks shifted toward a high angle. This meant that F was successfully incorporated into the oxyhalide system.

[0129] FIG. 3 is a graph showing the ionic conductivities of Examples 1 to 7, FIG. 4 is a graph showing the ionic conductivities of Examples 8 to 10, FIG. 5 is a graph showing the ionic conductivities of Examples 11 to 14, FIG. 6 is a graph showing the ionic conductivities of Examples 15 to 17, and FIG. 7 is a graph showing the ionic conductivities of Examples 18 to 19. For the measurement of ionic conductivity, a solid electrolyte was placed in a mold with a diameter of 10 mm and a pressure of about 30 MPa was applied to make a pellet of about 0.14 cm. For the measurement of ionic conductivity, indium foil was attached to both sides of the pellet. The ionic conductivity analysis was performed using a Biologic SP 300 instrument in the frequency range of 7 MHz to 1 Hz at 25°C. The ionic conductivity of Example 1 was 2.51 mS / cm, and the ionic conductivities of Examples 2 to 7 were 2.53, 2.77, 6.09, 6.7, 7.34, 6.06, and 4.33 mS / cm, respectively. The ionic conductivities of Examples 8 to 10 were 5.99, 4.38, and 2.77 mS / cm, respectively, and the ionic conductivities of Examples 11 to 14 were 0.22, 1.24, 1.30, and 1.28 mS / cm, respectively. The ionic conductivities of Examples 15 to 17 were 0.1, 0.15, and 0.15 mS / cm, respectively, and the ionic conductivities of Examples 18 to 19 were 4.25 and 6.98 mS / cm.

[0130]

[0131] <Example 20>

[0132] An all-solid-state battery was assembled using the solid electrolyte manufactured in Example 1. The cathode composite was LiNi 0.8 Co 0.1 Mn 0.1O2 (NCM 811), solid electrolyte (Example 1), and vapor-grown carbon fiber (VGCF) were composed in a weight ratio of 70:27:3. The cathode composite was uniformly mixed using a manual grinding process for approximately 45 minutes. For coin cell assembly, 0.2 g of lithium-argyrodite solid electrolyte was pelletized (diameter: 16 mm, thickness: ~1 mm) at 20 MPa for 2 minutes, and then 0.070 g of the solid electrolyte of Example 1 was dispersed on the pellet and pressed at 20 MPa for 2 minutes. The cathode composite was then dispersed on the solid electrolyte side of Example 1 and pressed at 50 MPa. Li foil was attached to the lithium-argyrodite solid electrolyte and pressurized at 30 MPa. Finally, a stainless steel spacer was attached to the cathode composite as a current collector.

[0133]

[0134] <Example 21>

[0135] An all-solid-state battery was manufactured in the same manner as in Example 20, except that the solid electrolyte of Example 5 was used instead of the solid electrolyte of Example 1.

[0136]

[0137] <Example 22>

[0138] An all-solid-state battery was manufactured in the same manner as in Example 20, except that the solid electrolyte of Example 8 was used instead of the solid electrolyte of Example 1.

[0139]

[0140] Experimental Example 2

[0141] Figure 8 is a charge / discharge curve of Examples 20 to 23. The charge / discharge curves are 2.5 to 4.25 V (vs. Li / Li) at various current densities. +) was verified using a Wonatek WBCS 3000 battery analyzer system in the voltage range. The all-solid-state battery of Example 21 containing the solid electrolyte of Example 5 showed excellent electrochemical performance.

[0142]

[0143] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A solid electrolyte comprising at least one compound selected from compounds represented by the following chemical formulas 1 to 3: [Chemical Formula 1] Li3MO 1+x H 4-2z [Chemical Formula 2] Li 3-y M 1-y M' y O 1+x H 4-2z [Chemical Formula 3] Li 3-2y M 1-y M' y O 1+x H 4-2z In the above chemical formula 1, 0≤x≤2, 0≤z≤2, M is one element selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, H is one halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 2, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a different element from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, Ti, Si, Zr, W, Mo, Ge and Sn, H is a halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 3, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

2. In paragraph 1, A solid electrolyte in which in the above chemical formula 1, M is Ta or Zr and H is Cl.

3. In paragraph 1, A solid electrolyte in which, in the chemical formula 2, M and M' are each a different element from the group consisting of Ta, Zr, P, Mo, Sb, and Na, and H is Cl.

4. In paragraph 1, A solid electrolyte in which in the above chemical formula 3, M is Ta or Zr, and H is Cl or F.

5. A solid electrolyte comprising at least one compound selected from compounds represented by the following chemical formulas 4 to 6: [Chemical Formula 4] Li3MCh 1+x H 4-2z [Chemical Formula 5] Li 3-y M 1-y M' y Combination 1+x H 4-2z [Chemical Formula 6] Li 3-2y M 1-y M' y Combination 1+x H 4-2z In the above chemical formula 4, 0≤x≤2, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, Ch is one chalcogen element selected from the group consisting of S, Se and Te, H is one halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 5, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M' is one metal selected from the group consisting of Ti, Si, Zr, W, Mo, Ge, and Sn, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, H is one halogen element selected from the group consisting of Cl, Br, I, and F, In the above chemical formula 6, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M” is one selected from the group consisting of P, Ta, Nb, and Sb, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

6. In paragraph 1 or paragraph 5, A solid electrolyte having a crystal structure comprising a trigonal system.

7. A method comprising: using a plurality of starting materials selected from the group consisting of alkali metals, alkali metal halides, alkali metal oxides, alkali metal sulfides, metal oxides, metal sulfides, alkali metal chalcogenides, metal chalcogenides, and metal halides; and mixing the plurality of starting materials. A method for producing a solid electrolyte, comprising producing a solid electrolyte of any one compound selected from the following chemical formulas 1 to 6: [Chemical Formula 1] Li3MO 1+x H 4-2z [Chemical Formula 2] Li 3-y M 1-y M' y O 1+x H 4-2z [Chemical Formula 3] Li 3-2y M 1-y M' y O 1+x H 4-2z [Chemical Formula 4] Li3MCh 1+x H 4-2z [Chemical Formula 5] Li 3-y M 1-y M' y Combination 1+x H 4-2z [Chemical Formula 6] Li 3-2y M 1-y M' y Combination 1+x H 4-2z In the above chemical formula 1, 0≤x≤2, 0≤z≤2, M is one element selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, H is one halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 2, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are each a different element from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb, Ti, Si, Zr, W, Mo, Ge and Sn, H is a halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 3, 0≤x≤2, 0≤y≤1, 0≤z≤2, M and M' are one metal selected from the group consisting of Y, Sc, In, Sb, Bi and Al, H is one halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 4, 0≤x≤2, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, Al, P, Ta, Nb and Sb, Ch is one chalcogen element selected from the group consisting of S, Se and Te, H is one halogen element selected from the group consisting of Cl, Br, I and F, In the above chemical formula 5, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M' is one metal selected from the group consisting of Ti, Si, Zr, W, Mo, Ge, and Sn, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, H is one halogen element selected from the group consisting of Cl, Br, I, and F, In the above chemical formula 6, 0≤x≤2, 0≤y≤1, 0≤z≤2, M is one metal selected from the group consisting of Y, Sc, In, Sb, Bi, and Al, M” is one selected from the group consisting of P, Ta, Nb, and Sb, Ch is one chalcogen element selected from the group consisting of S, Se, and Te, and H is one halogen element selected from the group consisting of Cl, Br, I, and F.

8. In paragraph 7, A method for producing a solid electrolyte, wherein the alkali metal halide comprises at least one selected from the group consisting of LiCl, NaCl, and KCl, the alkali metal oxide comprises at least one selected from the group consisting of Li2O, Na2O, and K2O, and the alkali metal sulfide comprises at least one selected from the group consisting of Li2S, Na2S, and K2S.

9. In paragraph 7, A method for producing a solid electrolyte, wherein the metal oxide comprises at least one selected from the group consisting of ZrO2, Nb2O5, Ta2O5, WO3, MoO3, P2O5, SiO2, GeO2, Sb2O3, Sb2O5, SnO2, In2O3, Bi2O3, MoO2, WO2, and Al2O3, and the metal sulfide comprises at least one selected from the group consisting of Sc2S3, Y2S3, TiS2, ZrS2, Nb2S5, Ta2S5, WS2, MoS2, P2S5, SiS2, GeS2, Sb2S3, Sb2S5, SnS2, In2S3, Bi2S3, MoS3, WS3, and Al2S3.

10. In paragraph 7, A method for producing a solid electrolyte, wherein the above mixing is performed using a ball mill at 300 to 100 rpm for 10 to 20 hours, and the starting materials are mixed.

11. Solid electrolyte according to paragraph 1 or paragraph 5; an anode disposed on one side of the solid electrolyte; and An all-solid-state secondary battery comprising a cathode disposed on the solid electrolyte surface.

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