KR102597452B1 - Lithium ion conductive halide-based solid electrolyte and method for synthesizing the same - Google Patents

Abstract

The present invention relates to a halogen-based solid electrolyte and a method for producing the same, and relates to a halogen having an orthorhombic crystal structure by combining lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) in a specific molar ratio. It is characterized by greatly improving its lithium ion conductivity by implementing a solid electrolyte.

Description

Halogen-based solid electrolyte with lithium ion conductivity and method for manufacturing the same {LITHIUM ION CONDUCTIVE HALIDE-BASED SOLID ELECTROLYTE AND METHOD FOR SYNTHESIZING THE SAME}

The present invention relates to a halogen-based solid electrolyte and a method for producing the same, and relates to a halogen having an orthorhombic crystal structure by combining lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) in a specific molar ratio. It is characterized by greatly improving its lithium ion conductivity by implementing a solid electrolyte.

Sulfide-based solid electrolytes, which are widely used in the development of all-solid-state batteries, are attracting attention due to their lithium ion conductivity equivalent to that of liquid electrolytes. However, sulfide-based solid electrolytes have very low electrochemical stability, causing cell deterioration due to side reactions with electrodes. In addition, sulfide-based solid electrolytes have problems such as atmospheric deterioration and low processability due to their compositional characteristics, so additional research is needed for mass production.

On the other hand, halogen-based solid electrolytes have relatively excellent electrochemical stability and have low reactivity with electrode materials. In addition, it has excellent reversible water solubility, making solution-based synthesis such as wet synthesis possible, making it suitable for mass production. Accordingly, many attempts are currently being made to develop all-solid-state batteries using halogen-based solid electrolytes.

Currently, materials with mechanical properties, lithium ion conductivity, and high productivity are being developed in crystalline solid electrolytes based on halogen elements.

The purpose of the present invention is to provide a halogen-based solid electrolyte with excellent lithium ion conductivity and electrochemical stability.

The object of the present invention is not limited to the objects mentioned above. The object of the present invention will become clearer from the following description and may be realized by means and combinations thereof as set forth in the claims.

The halogen-based solid electrolyte according to an embodiment of the present invention may be represented by the following Chemical Formula 1.

[Formula 1]

(LiCl) _x (FeCl ₂ ) _y (FeCl ₃ ) _z

Here, 0.35≤x≤0.85, 0.00<y≤0.60, and 0.00<z≤0.40 are satisfied.

The halogen-based solid electrolyte may satisfy 0.50≤x≤0.75 and 0.25≤2y+3z≤0.50 in Chemical Formula 1.

The halogen-based solid electrolyte may have an orthorhombic crystal structure.

The halogen-based solid electrolyte may show a peak at 2θ=17.25°±0.50° when measuring an X-ray diffraction pattern using CuKα rays.

When measuring an It may show peaks at 34.5˚±0.50˚, 2θ=45.6˚±0.50˚, and 2θ=50.0˚±1.00˚.

The halogen-based solid electrolyte may satisfy Equation 1 below.

[Equation 1]

7.50 < I ₍₀₀₂₎ / (I ₍₀₁₁₎ + I ₍₀₀₂₎ ) × 100 < 20.50

Here, I ₍₀₁₁₎ is the diffraction intensity of the XRD peak at 2θ=14.86°±0.50°, and I ₍₀₀₂₎ is the diffraction intensity of the

The halogen-based solid electrolyte has a first peak (Peak-1) at a binding energy of 708 eV to 713 eV in the Fe-XPS spectrum obtained by X-ray photoelectron spectroscopy (XPS), and a binding energy of 713.53 ± 0.55 eV. The second peak (Peak-2) may be detected at a binding energy of 715.41 ± 0.22 eV, the third peak (Peak-3), and the fourth peak (Peak-4) may be detected at a binding energy of 718.24 ± 0.44 eV.

The halogen-based solid electrolyte may satisfy Equation 2 below.

[Equation 2]

0 ≤ A _{Peak -4} / (A _{Peak -3} + A _{Peak -4} ) × 100 ≤ 85

A _{Peak - 3} is the area of the peak detected at a binding energy of 715.41 ± 0.22 eV in the Fe-XPS spectrum obtained by X-ray photoelectron spectroscopy (XPS), and A _{Peak -4} is the area of the peak detected by X-ray photoelectron spectroscopy (XPS). This is the area of the peak detected at a binding energy of 718.24 ± 0.44 eV in the Fe-XPS spectrum obtained by .

The method for producing a halogen-based solid electrolyte according to an embodiment of the present invention involves weighing starting materials containing lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) according to the composition according to Chemical Formula 1. Preparing steps; and grinding the starting material.

The manufacturing method may further include heat treating the pulverized material at a temperature of 30°C to 1,000°C for 10 seconds to 1,000 hours.

According to the present invention, a halogen-based solid electrolyte with excellent lithium ion conductivity and electrochemical stability can be obtained.

The effects of the present invention are not limited to the effects mentioned above. The effects of the present invention should be understood to include all effects that can be inferred from the following description.

Figure 1 shows lithium ion conductivity results according to the molar ratio of three raw materials (LiCl, FeCl ₂ , FeCl ₃ ) based on examples and comparative examples as a contour map.
Figure 2 shows the results of X-ray diffraction (XRD) analysis of the halogen-based solid electrolyte according to Examples 1 to 5 and Comparative Example 5.
Figure 3 shows the intensity ratio between the (002) peak and the (011) peak observed in the XRD results of Examples 1 to 5 and Comparative Example 5.
Figure 4 shows the results of Fe-XPS analysis of the halogen-based solid electrolytes according to Examples 1 to 5 and Comparative Example 5.
Figure 5 shows the results of substituting the Fe-XPS results of the halogen-based solid electrolytes according to Examples 1 to 5 and Comparative Example 5 into Equation 2.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments related to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

While describing each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of the structures are enlarged from the actual size for clarity of the present invention. Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof. Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “on” another part, this includes not only being “directly above” the other part, but also cases where there is another part in between. Conversely, when a part of a layer, membrane, region, plate, etc. is said to be "underneath" another part, this includes not only being "immediately below" the other part, but also cases where there is another part in between.

Unless otherwise specified, all numbers, values, and/or expressions used herein expressing quantities of components, reaction conditions, polymer compositions, and formulations are intended to represent, among other things, how such numbers inherently occur in obtaining such values. Since they are approximations reflecting the various uncertainties of measurement, they should be understood in all cases as being qualified by the term "approximately". Additionally, where a numerical range is disclosed herein, such range is continuous and, unless otherwise indicated, includes all values from the minimum to the maximum of such range inclusively. Furthermore, when such range refers to an integer, all integers from the minimum value up to and including the maximum value are included, unless otherwise indicated.

The halogen-based solid electrolyte according to the present invention may be represented by the following formula (1).

[Formula 1]

(LiCl) _x (FeCl ₂ ) _y (FeCl ₃ ) _z

Here, 0.35≤x≤0.85, 0.00<y≤0.60, and 0.00<z≤0.40 may be satisfied. Preferably, 0.50≤x≤0.75 and 0.25≤2y+3z≤0.50 may be satisfied.

When the halogen-based solid electrolyte satisfies the above composition, it can exhibit high lithium ion conductivity.

The halogen-based solid electrolyte may have an orthorhombic crystal structure. Accordingly, the halogen-based solid electrolyte according to the present invention shows improved lithium ion conductivity compared to the conventional one having a cubic crystal structure.

The method for producing a halogen-based solid electrolyte according to the present invention includes preparing starting materials including lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) by weighing them according to the composition according to Chemical Formula 1, It may include the step of pulverizing the starting material and heat treating the pulverized product.

The present invention is characterized by using iron trichloride in a specific ratio as a starting material to obtain a halogen-based solid electrolyte having an orthorhombic crystal structure and the composition of Chemical Formula 1.

First, the starting material is pulverized and amorphized to obtain a glassy pulverized product. Methods for pulverizing the starting material include mechanical milling and melt quenching, and among them, mechanical milling is preferable. This is because processing at room temperature is possible and the manufacturing process can be simplified.

Mechanical milling can be performed using any method or device as long as it can grind and mix the starting material while applying mechanical energy to it. For example, ball mills such as electric ball mills, vibrating ball mills, and planetary ball mills; Vibration Mixer Mill or SPEX Mill; It can be performed in such a way. Preferably, a planetary ball mill can be used. Specifically, when starting materials and beads are placed in a container and the planetary ball mill device is operated, the beads in the container rotate along the inner wall of the container and crush the raw materials through friction. At this time, the rotation speed can be varied and the process time according to the rotation speed can be controlled in various ways to apply differentiated grinding conditions. Additionally, the equilibrium temperature applied during grinding can be controlled by adding an external cooling or heating device during grinding.

Thereafter, the amorphized pulverized product can be heat treated to obtain a crystallized halogen-based solid electrolyte. The conditions of heat treatment are not particularly limited, but may be performed at a temperature higher than the crystallization temperature of the ground product. For example, the heat treatment step may involve heat treating the pulverized material at a temperature of 30°C to 1,000°C for 10 seconds to 1,000 hours.

The crystalline halogen-based solid electrolyte prepared by the above method shows completely different properties from conventional materials. This was analyzed through the examples and experimental examples below.

Example 1 - ( LiCl ) _0.582 ( FeCl ₂ ) _0.382 ( FeCl ₃ ) _0.036 Composite (x=0.582; y=0.382; z=0.036)

Starting materials containing lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) at a molar ratio of 0.582:0.382:0.036, respectively, were prepared.

The starting material was charged into a gas-tight milling container, and a bead with a diameter of 3 mm made of zirconium oxide was added thereto. At this time, the amount of beads input was about 27.5 times the weight of the raw material. As described above, the starting material was pulverized using a planetary ball mill method that generates high inertial force. Specifically, the container was rotated so that a force of about 30G was applied to the mixture, and 18 cycles were continuously performed, with 30 minutes of grinding and 10 minutes of stopping as one cycle. After grinding, the powdered product was recovered through appropriate sieving and mortar grinding.

Thereafter, the pulverized material was heat treated to prepare a crystalline halogen-based solid electrolyte.

Example 2 inside Example 12

A halogen-based solid electrolyte was prepared in the same manner as in Example 1, except that lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) were prepared as starting materials in the molar ratios shown in Table 1 below.

Comparative Example 1 - ( LiCl ) _0.571 ( FeCl ₂ ) _0.429 Composite (x=0.571; y=0.429; z=0.00)

A halogen-based solid electrolyte was prepared in the same manner as in Example 1, except that iron trichloride (FeCl ₃ ) was not used as a starting material, and lithium chloride (LiCl) and iron dichloride (FeCl ₂ ) were prepared at a molar ratio of 0.571:0.429. Manufactured.

Comparative example 2 - ( LiCl ) _0.833 ( FeCl ₂ ) _0.167 Composite (x=0.833; y=0.167; z=0.00)

A halogen-based solid electrolyte was prepared in the same manner as in Example 1, except that iron trichloride (FeCl ₃ ) was not used as a starting material, and lithium chloride (LiCl) and iron dichloride (FeCl ₂ ) were prepared at a molar ratio of 0.833:0.167. Manufactured.

Comparative example 3 - ( LiCl ) _0.643 ( FeCl ₂ ) _0.357 Composite (x=0.643; y=0.357; z=0.00)

A halogen-based solid electrolyte was prepared in the same manner as in Example 1, except that iron trichloride (FeCl ₃ ) was not used as a starting material, and lithium chloride (LiCl) and iron dichloride (FeCl ₂ ) were prepared at a molar ratio of 0.643:0.357. Manufactured.

Comparative Example 4 - ( LiCl ) _0.756 ( FeCl ₂ ) _0.244 Composite (x=0.756; y=0.244; z=0.00)

A halogen-based solid electrolyte was prepared in the same manner as in Example 1, except that iron trichloride (FeCl ₃ ) was not used as a starting material, and lithium chloride (LiCl) and iron dichloride (FeCl ₂ ) were prepared at a molar ratio of 0.756:0.244. Manufactured.

Comparative Example 5 - ( LiCl ) _0.667 ( FeCl ₂ ) _0.333 Composite (x=0.667; y=0.333; z=0.00)

In 2020, Adv. Energy Sustainability Res. Vol. A solid electrolyte having a cubic structure and expressed as Li ₂ FeCl ₄ was prepared by the method described in 1, Page.

Experimental Example 1 - Measurement of lithium ion conductivity through AC impedance measurement

AC impedance analysis was performed at room temperature to measure the lithium ion conductivity of the halogen-based solid electrolytes according to Examples 1 to 12 and Comparative Examples 1 to 5. Each powder was charged into a conductivity measurement mold, and a sample with a diameter of 6 mm and a thickness of 2.5 mm was produced through uniaxial cold pressing at 300 Mpa. An alternating potential of 100 mV was applied to the sample, and a frequency sweep was performed from 1 Hz to 3 MHz to obtain the impedance of the sample. The results are shown in Table 1.

division chemical formula molar ratio ionic conductivity
(mS/cm) x y z Example 1 (LiCl) _0.582 (FeCl ₂ ) _0.382 (FeCl ₃ ) _0.036 0.582 0.382 0.036 0.067 Example 2 (LiCl) _0.593 (FeCl ₂ ) _0.333 (FeCl ₃ ) _0.074 0.593 0.333 0.074 0.070 Example 3 (LiCl) _0.604 (FeCl ₂ ) _0.283 (FeCl ₃ ) _0.113 0.604 0.283 0.113 0.120 Example 4 (LiCl) _0.615 (FeCl ₂ ) _0.231 (FeCl ₃ ) _0.154 0.615 0.231 0.154 0.200 Example 5 (LiCl) _0.627 (FeCl ₂ ) _0.176 (FeCl ₃ ) _0.196 0.627 0.176 0.196 0.230 Example 6 (LiCl) _0.550 (FeCl ₂ ) _0.252 (FeCl ₃ ) _0.198 0.550 0.252 0.198 0.028 Example 7 (LiCl) _0.661 (FeCl ₂ ) _0.219 (FeCl ₃ ) _0.120 0.661 0.219 0.120 0.184 Example 8 (LiCl) _0.725 (FeCl ₂ ) _0.137 (FeCl ₃ ) _0.137 0.725 0.137 0.137 0.081 Example 9 (LiCl) _0.449 (FeCl ₂ ) _0.346 (FeCl ₃ ) _0.206 0.449 0.346 0.206 0.067 Example 10 (LiCl) _0.506 (FeCl ₂ ) _0.468 (FeCl ₃ ) _0.027 0.506 0.468 0.027 0.034 Example 11 (LiCl) _0.519 (FeCl ₂ ) _0.403 (FeCl ₃ ) _0.078 0.519 0.403 0.078 0.080 Example 12 (LiCl) _0.526 (FeCl ₂ ) _0.368 (FeCl ₃ ) _0.105 0.526 0.368 0.105 0.130 Comparative Example 1 (LiCl) _0.571 (FeCl ₂ ) _0.429 0.571 0.429 0.000 0.024 Comparative example 2 (LiCl) _0.833 (FeCl ₂ ) _0.167 0.833 0.167 0.000 0.024 Comparative Example 3 (LiCl) _0.764 (FeCl ₂ ) _0.236 0.764 0.236 0.000 0.022 Comparative Example 4 (LiCl) _0.756 (FeCl ₂ ) _0.244 0.756 0.244 0.000 0.008 Comparative Example 5 (LiCl) _0.667 (FeCl ₂ ) _0.333 0.667 0.333 0.000 0.021

It can be seen that the halogen-based solid electrolytes according to Comparative Examples 1 to 5 showed lithium ion conductivity of about 0.02 mS/cm, while the halogen-based solid electrolytes according to the present invention all showed higher lithium ion conductivity. .

In particular, the solid electrolyte of Example 5 showed a lithium ion conductivity of about 0.23 mS/cm, which was more than 10 times more improved than the conventional halogen-based solid electrolyte.

Figure 1 shows lithium ion conductivity results according to the molar ratio of three raw materials (LiCl, FeCl ₂ , FeCl ₃ ) based on the above examples and comparative examples as a contour map. Based on Figure 1, the molar ratio of LiCl and FeCl ₂ that exhibit high ionic conductivity can be confirmed, and the corresponding ratio of FeCl ₃ can be derived.

Experimental Example 2 - XRD through analysis solid electrolyte Crystal structure observation

X-ray diffraction (XRD) analysis was performed on the halogen-based solid electrolytes according to Examples 1 to 5 and Comparative Example 5. Each sample was placed in a sealed XRD-specific holder and the area of 10˚ ≤ 2θ ≤ 60˚ was measured at a scan speed of 3˚ per minute. The results are shown in Figure 2.

Referring to this, the halogen-based solid electrolytes according to Examples 1 to 5 had 2θ=14.8˚±0.5˚, 2θ=17.25˚±0.50˚, 2θ=27.0˚±0.50 when measuring the X-ray diffraction pattern using CuKα rays. Peaks appear at ˚, 2θ=30.0˚±0.50˚, 2θ=34.5˚±0.50˚, 2θ=45.6˚±0.50˚, and 2θ=50.0˚±1.00˚. This matches the peak appearing in the orthorhombic crystal structure (#04-010-0693). Therefore, it can be confirmed that the solid electrolyte according to the present invention has an orthorhombic crystal structure.

In addition, in the halogen-based solid electrolyte according to the present invention, a (002) peak is found at 2θ = 17.25˚±0.50˚, which is not observed in the halogen-based solid electrolyte having a cubic crystal structure of Comparative Example 5. Accordingly, the intensity ratios between the (002) peak and the (011) peak observed in the results of Examples 1 to 5 and Comparative Example 5 are shown in Table 2 and Figure 3 below.

division I _(002)/ I ₍₀₁₁₎ +I ₍₀₀₂₎ × 100 (%) Example 1 8.76 Example 2 11.00 Example 3 13.19 Example 4 15.83 Example 5 19.13 Comparative Example 5 0.00

Through this, it can be seen that the halogen-based solid electrolyte according to the present invention satisfies Equation 1 below.

[Equation 1]

7.50 < I ₍₀₀₂₎ / (I ₍₀₁₁₎ + I ₍₀₀₂₎ ) × 100 < 20.50

Here, I ₍₀₁₁₎ is the diffraction intensity of the XRD peak at 2θ=14.86°±0.50°, and I ₍₀₀₂₎ is the diffraction intensity of the

Experimental Example 3 - XPS through analysis solid electrolyte Observation of crystal properties

Fe-XPS analysis was performed on the halogen-based solid electrolytes according to Examples 1 to 5 and Comparative Example 5. Each sample was placed in a sealed vacuum transfer vessel, and monochromated Al Kα having 1486.6 eV was irradiated to a beam irradiation area of 100㎛ x 100㎛ to measure the photoelectrons emitted from the sample. The results are shown in Table 3 and Figure 4.

Referring to Table 3 and Figure 4 below, the halogen-based solid electrolytes according to Examples 1 to 5 have a binding energy (Binding) of 706 eV to 722 eV based on the X-ray photovoltaic spectroscopy (XPS) measurement spectrum for iron (Fe). energy). Specifically, the first peak (Peak-1) at a binding energy of 708 eV to 713 eV, the second peak (Peak-2) at a binding energy of 713.53 ± 0.55 eV, and the third peak at a binding energy of 715.41 ± 0.22 eV. (Peak-3) and the fourth peak (Peak-4) are detected at a binding energy of 718.24 ± 0.44 eV.

The first peak is Peak-1a found at a binding energy of 708.86±0.25 eV, Peak-1b found at a binding energy of 709.85±0.31 eV, and Peak-1c found at a binding energy of 710.80±0.47 eV, 711.65±0.46. It can be divided into Peak-1d, which is found at a binding energy of eV, and Peak-1e, which is found at a binding energy of 711.65±0.46 eV.

Meanwhile, in the halogen-based solid electrolyte according to Comparative Example 5, unlike the present invention, the fourth peak was not detected.

division A _{Peak -1a} A _{Peak -1b} A _{Peak -1c} A _{Peak -1d} A _{Peak -1e} A _{Peak -2} A _{Peak -3} A _{Peak -4} Equation 2 Example 1 385 1272 911 818 436 222 1920 160 7.69 Example 2 227 859 822 742 551 217 1708 82 4.58 Example 3 165 583 731 603 463 232 1289 85 6.19 Example 4 107 506 569 561 473 268 1207 77 6.00 Example 5 - 768 1236 2488 1176 602 242 1039 81.11 Comparative Example 5 202 997 1325 1099 723 343 1865 - 0.00

In Table 3, A _{Peak -1a} is the area of the Fe-XPS peak with Binding energy = 708.86 ± 0.25 eV, A _{Peak -1b} is the area of the Fe-XPS peak with Binding energy = 709.85 ± 0.31 eV, and A _{Peak -1c} is _Binding energy _{= 710.80 ±} 0.47 eV is the area of the Fe- A _{Peak -2} is the area of the Fe-XPS peak with binding energy=713.53±0.55 eV, A _{Peak - 3} is the area of the Fe-XPS peak with binding energy=715.41±0.22 eV, A _{Peak -4} is Fe-XPS with Binding energy=718.24± 0.44eV.

Through this, it can be seen that the halogen-based solid electrolyte according to the present invention satisfies Equation 2 below.

[Equation 2]

0% ≤ A _{Peak -4} / (A _{Peak -3} + A _{Peak -4} ) × 100 ≤ 85%

Figure 5 shows the results of substituting the Fe-XPS results of the halogen-based solid electrolytes according to Examples 1 to 5 and Comparative Example 5 into the equation of Equation 2 above.

The lithium ion conductive halogen-based solid electrolyte according to the present invention can be used in all electrochemical cells using solid electrolytes. Specifically, it can be applied to various fields and products, such as energy storage systems using secondary batteries, batteries for electric vehicles or hybrid electric vehicles, unmanned robots, or portable power supply systems for the Internet of Things.

As the experimental examples and examples of the present invention have been described in detail above, the scope of the present invention is not limited to the above-mentioned experimental examples and examples, and the basic concept of the present invention defined in the following claims is Various modifications and improvements made by those skilled in the art are also included in the scope of the present invention.

Claims (10)

A halogen-based solid electrolyte represented by the following formula (1).
[Formula 1]
(LiCl) _x (FeCl ₂ ) _y (FeCl ₃ ) _z
Here, 0.35≤x≤0.85, 0.00<y≤0.60, and 0.00<z≤0.40 are satisfied. According to paragraph 1,
A halogen-based solid electrolyte satisfying 0.50≤x≤0.75 and 0.25≤2y+3z≤0.50 in Chemical Formula 1. According to paragraph 1,
Halogen-based solid electrolyte with an orthorhombic crystal structure. According to paragraph 1,
A halogen-based solid electrolyte that shows a peak at 2θ=17.25˚±0.50˚ when measuring an X-ray diffraction pattern using CuKα rays. According to paragraph 1,
When measuring an Halogen-based solid electrolyte showing peaks at 2θ=45.6˚±0.50˚ and 2θ=50.0˚±1.00˚. According to paragraph 1,
A halogen-based solid electrolyte that satisfies Equation 1 below.
[Equation 1]
7.50 < I ₍₀₀₂₎ / (I ₍₀₁₁₎ + I ₍₀₀₂₎ ) × 100 < 20.50
Here, I ₍₀₁₁₎ is the diffraction intensity of the XRD peak at 2θ=14.86°±0.50°, and I ₍₀₀₂₎ is the diffraction intensity of the According to paragraph 1,
In the Fe-XPS spectrum obtained by X-ray photoelectron spectroscopy (XPS)
The first peak (Peak-1) at a binding energy of 708 eV to 713 eV,
The second peak (Peak-2) at a binding energy of 713.53±0.55 eV,
The third peak (Peak-3) at a binding energy of 715.41±0.22 eV and
A halogen-based solid electrolyte in which the fourth peak (Peak-4) is detected at a binding energy of 718.24 ± 0.44 eV. According to paragraph 1,
A halogen-based solid electrolyte that satisfies Equation 2 below.
[Equation 2]
0 ≤ A _{Peak -4} / (A _{Peak -3} + A _{Peak -4} ) × 100 ≤ 85
A _{Peak - 3} is the area of the peak detected at a binding energy of 715.41 ± 0.22 eV in the Fe-XPS spectrum obtained by X-ray photoelectron spectroscopy (XPS),
A _{Peak -4} is the area of the peak detected at a binding energy of 718.24 ± 0.44 eV in the Fe-XPS spectrum obtained by X-ray photoelectron spectroscopy (XPS). A method for producing the halogen-based solid electrolyte of any one of claims 1 to 8,
Preparing starting materials including lithium chloride (LiCl), iron dichloride (FeCl ₂ ), and iron trichloride (FeCl ₃ ) by weighing them according to the composition according to Chemical Formula 1; and
A method for producing a halogen-based solid electrolyte comprising the step of pulverizing the starting material. According to clause 9,
A method for producing a halogen-based solid electrolyte, further comprising heat-treating the pulverized material at a temperature of 30°C to 1,000°C for 10 seconds to 1,000 hours.