KR20240018358A - Solid ion conductor compound, solid electrolyte comprising the same, electrochemical cell comprising the same, and preparation method thereof - Google Patents

Abstract

The present invention relates to a solid ion conductor compound including the compound represented by Formula 1 described herein, a method for manufacturing the same, and an electrochemical cell including the same.

Description

Solid ion conductor compound, solid electrolyte comprising the same, electrochemical cell comprising the same, and manufacturing method thereof {Solid ion conductor compound, solid electrolyte comprising the same, electrochemical cell comprising the same, and preparation method thereof}

It relates to a solid ion conductor compound, a solid electrolyte containing the same, a lithium battery containing the same, and a method of manufacturing the same.

All-solid-state lithium batteries contain a solid electrolyte as an electrolyte. All-solid-state lithium batteries have excellent stability because they do not contain flammable organic solvents.

Conventional solid electrolyte materials are not sufficiently stable toward lithium metal. Additionally, the lithium ion conductivity of conventional solid electrolytes is lower than that of liquid alternatives.

One aspect is to provide a solid ion conductor compound with excellent lithium ion conductivity by having a new composition.

According to one aspect, a solid ion conductor compound including a compound represented by the following formula (1) is provided.

<Formula 1>

M _{3+m+(l-1)o+2p ( M} ^{' k +} _{) n}

In Formula 1,

M is one or more alkali metals,

M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals,

X is one or more halogen elements,

T is one or more monovalent or divalent anions,

Z is one or more trivalent anions,

2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q).

In one embodiment, M includes Li, Na, K, Rb, Cs, or a combination thereof. For example, M may include Li, Na, or a combination thereof.

In one embodiment, M' is Mg, Zn, Ca, Sr, Ba, Eu, Y, Gd, In, Er, La, Yb, Ce, Ho, Sn, Th, Nb, Mo, W, Sb, Bi , Zr, Hf, Ti, Si, or a combination thereof.

In one embodiment, X may include F, Cl, Br, I, or a combination thereof.

In one embodiment, Z is PO ₄ ^3- _, (C ₆ H ₅ O ₇ ) ^3- , PS ₄ ^3- _, [Fe(CN)] ^3- , [Ag(S ₂ O ₃ ) ₂ ] ^3- , N ^3- , P ^3- , or a combination thereof, and for example, Z may be a trivalent polyatomic ion.

In one embodiment, T may include NO ₃ ^- , CH ₃ COO ^- , OH ^- , HCO ₃ ^- , CrO ₄ ^2- , SO ₄ ^2- , CO ₃ ^2- , BH ₄ ^-, or a combination thereof. there is.

In one embodiment, 3≤k≤5.

In one embodiment, -3≤m≤0.5.

In one embodiment, 0<p≤0.3.

In one embodiment, 2<3+m+(l-1)o+2p<3.

In one embodiment, 5.8≤3+m+kn-lo-3p+q<6.

In one embodiment, Formula 1 may be represented by Formula 2 below:

<Formula 2>

(Li _1-h M _h ) _{3+m+(l-1)o+2p} ⁽ _{M ' k +} ⁾ _n ' _i ) _p

In Formula 2 above,

M is one or more alkali metals excluding Li,

Z' is one or more trivalent anions excluding PO ₄ ^3- ,

M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals,

X is one or more halogen elements,

T is one or more monovalent or divalent anions,

2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q), 0≤h<1, 0≤i<1.

In one embodiment, M may be Na, a solid ion conductor compound.

In one embodiment, 0≤h≤0.5.

In one embodiment, 0≤i≤0.5.

In one embodiment, Formula 1 may be represented by Formula 3:

<Formula 3>

(Li _1-h M _h ) _{3+m+(l-1)o+2p (} ( ^Zr ) _{1 -j} M' _j ^k+ ) _n PO ₄ ) _1-i Z' _i ) _p

Of the above formula 3,

M is one or more alkali metals excluding Li,

Z' is one or more trivalent anions excluding PO ₄ ^3- ,

M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals excluding Zr,

X is one or more halogen elements,

T is one or more monovalent or divalent anions,

2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q), 0≤h<1, 0≤i<1, 0≤j<1.

In one embodiment, 0≤j≤0.5.

In one embodiment, the solid ion conductor compound has diffraction angles 2θ=16°±0.5°, 20°±0.5°, 30°±0.5°, 32°±0.5°, 42°± in the XRD spectrum using CuKα line. It may have diffraction peaks at 0.5 and 50°±0.50.

In one embodiment, the solid ion conductor compound may have an ionic conductivity of 0.3 mScm ^-1 or more at 25°C.

In one embodiment, the solid ion conductor compound may have a crystalline phase, an amorphous phase, or a combination thereof.

In one embodiment, the solid ion conductor compound may include a crystal belonging to the P3-m1 space group.

In one embodiment, the solid ion conductor compound may have increased a- and c-axis lattice constants compared to a compound that does not contain a trivalent anion represented by Z.

In one embodiment, the solid ion conductor compound is Li _2.1 ZrCl _5.95 (PO ₄ ) _0.05 , Li _2.02 ZrCl _5.99 (PO ₄ ) _0.01 , Li _2.04 ZrCl _5.98 (PO ₄ ) _0.02 , Li _2.08 ZrCl _5.96 (PO ₄ ) _0.04 , Li _2.12 ZrCl _5.94 (PO ₄ ) _0.06 , Li _2.2 ZrCl _5.9 (PO ₄ ) _0.1 , Li _2.15 Zr _0.8 Y _0.2 Cl _5.95 (PO ₄ ) _0.05 , Li _2.45 Zr _0.5 Y _0.5 Cl _5.95 (PO ₄ ) _0.05 , Li _2.22 ZrCl _5.89 (PO ₄ ) _0.11 , Li _2.24 ZrCl _5.88 (PO ₄ ) _0.12 , It may be Li _2.3 ZrCl _5.85 (PO ₄ ) _0.15, Li _2.4 ZrCl _5.8 (PO ₄ ) _0.2 , Li _2.6 ZrCl _5.7 (PO ₄ ) _0.3 or Li _2.1 ZrCl _5.95 (PS ₄ ) _0.05 .

According to another aspect, preparing a mixture comprising a halide compound containing an M element, a halide compound containing an M' element, and a Z element containing compound, wherein the M element is at least one alkali metal, and the M' element is divalent, It is one or more metals selected from trivalent, tetravalent, pentavalent and hexavalent metals, and the Z element is one or more trivalent anions,

A method for producing a solid ion conductor compound is provided, including the step of reacting the mixture in a solid phase to obtain a solid ion conductor compound.

In one embodiment, the step of reacting the mixture in a solid phase to obtain a solid ion conductor compound is,

It may include performing ball mill mixing of the mixture in a dry and inert atmosphere.

In one embodiment, the ball mill mixing is performed at a first time interval, the ball mill mixing further includes a rest period after the first time interval, and the time interval and the rest period may be repeated.

According to another aspect, a positive electrode layer including a positive electrode active material layer;

A negative electrode layer including a negative electrode active material layer; and

It includes a solid electrolyte layer sandwiched between the anode layer and the cathode layer,

An electrochemical cell is provided, including the solid ion conductor compound in at least one of the anode layer and the solid electrolyte layer.

In one embodiment, the solid electrolyte layer may include a sulfide-based solid electrolyte.

In one embodiment, the positive electrode active material layer includes a positive electrode active material represented by LiNi _x Co _y Al _z O ₂ or LiNi _x' Co _y' Mn _z' O ₂ , where 0 < x < 1, 0 < y < 1, 0 < z < 1, x + y + z = 1, and 0 <x'< 1, 0 <y'< 1, 0 <z'< 1, x' + y' + z' = 1 day. You can.

In one embodiment, the negative electrode active material layer may include metallic lithium.

In one embodiment, when the electrochemical cell is charged and discharged at 0.1C in the range of 2.5V to 4.2V, the discharge capacity can be maintained at more than 93% after 20 cycles compared to the initial discharge capacity.

In one embodiment, the electrochemical cell may be an all-solid-state secondary battery.

According to one aspect, an electrochemical cell with improved cycle characteristics is provided by including a solid ion conductor compound with improved lithium ion conductivity.

1 shows intensity (au) vs. diffraction results of X-ray diffraction analysis (XRD) using Cu-Ka radiation for the solid ion conductor powders of Examples 1, 2, 4, 5, and 6 and Comparative Example 1. This is the spectrum of angle (°2θ).
Figure 2 is an enlarged view of the diffraction angle 2θ=32.3° peak in the XRD spectrum of Figure 1.
Figure 3 shows a graph of lattice constant (ㅕ) vs Li _2+2x Zr _1-x Cl _6-x (PO ₄ ) _x for x, Examples 1, 2, 4, 5, 6 and Comparative Example 1 This figure shows the calculated lattice constant of the crystal structure of the solid ionic conductor powder.
4 shows a graph of ionic conductivity (S cm ^-1 ) vs Li _2+2x Zr _1-x Cl _6-x (PO ₄ ) _x versus x, Examples 1 to 6, Examples 10 to 14; and a graph showing the ionic conductivity according to the change in the molar ratio of trivalent anions of the solid ion conductor powder of Comparative Example 1.
Figure 5 shows a graph of specific capacity (mAh g ^-1 ) vs. number of cycles, and is a graph of charging and discharging of the all-solid-state batteries of Example 10 and Comparative Example 8.
Figure 6 is a graph showing specific capacity (mAh g ^-1 ) vs C rate, and is a graph showing the rate characteristics of the all-solid-state batteries of Example 10 and Comparative Examples 8 and 9.
Figure 7 is a schematic diagram of an embodiment of an all-solid-state secondary battery.
Figure 8 is a schematic diagram of another embodiment of an all-solid-state secondary battery.
Figure 9 is a graph of intensity (au) vs. binding energy (eV), and is a graph confirming the presence of PO ₄ ions from the XPS data of Example 1.
<Explanation of symbols for main parts of the drawing>
1, 1a: All-solid secondary battery 10: Anode
11: positive electrode current collector 12: positive electrode active material layer
20: cathode 21: cathode current collector
22: negative electrode active material layer 23: metal layer
30: solid electrolyte layer

Various implementation examples are shown in the accompanying drawings. However, this creative idea can be embodied in many different forms, and should not be construed as limited to the implementation examples described in this specification. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present creative idea to those skilled in the art. Like reference numerals refer to like elements.

It will be understood that when an element is referred to as being “on” another element, it may be directly on top of the other element, or there may be other elements intervening between them. In contrast, when an element is said to be “directly on” another element, there are no intervening elements between them.

Terms such as “first,” “second,” “third,” and the like may be used herein to describe various components, components, regions, layers, and/or sections; Layers and/or zones should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Accordingly, a first component, component, region, layer or section described below may be referred to as a second component, component, region, layer or section without departing from the teachings herein.

The terms used in this specification are intended to describe only specific implementation examples and are not intended to limit the creative idea. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly dictates otherwise. “At least one” should not be construed as limiting to the singular. As used herein, the term “and/or” includes any and all combinations of one or more of the listed items. As used in the detailed description, the terms "comprise" and/or "comprising" specify the presence of a specified feature, area, integer, step, operation, component and/or component, and one or more other features, areas, integers, or elements. , does not exclude the presence or addition of steps, operations, components, ingredients and/or groups thereof.

Spatially relative terms such as “bottom,” “bottom,” “bottom,” “above,” “upper,” etc. are used to facilitate describing the relationship of one component or feature to another component or feature. It can be used here for: It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures were turned over, elements described as “below” or “below” other elements or features would be oriented “above” the other elements or features. Accordingly, the exemplary term “down” can encompass both upward and downward directions. The device can be positioned in different orientations (rotated 90 degrees or rotated in other directions) and the spatially relative terms used herein can be interpreted accordingly.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. Additionally, it is also understood that terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings within the context of the related art and present disclosure, and should not be interpreted in an idealized or overly formal sense. It will be.

Exemplary implementations are described herein with reference to cross-sectional diagrams, which are schematic diagrams of idealized implementations. As such, variations from the shape of the city should be expected, for example as a result of manufacturing techniques and/or tolerances. Accordingly, the embodiments described herein should not be construed as limited to the specific shapes of the regions as shown herein, but should include variations in shapes resulting, for example, from manufacturing. For example, areas shown or described as flat may typically have rough and/or non-linear features. Moreover, angles shown as sharp may be rounded. Accordingly, the areas shown in the drawings are schematic in nature and the shapes are not intended to depict the exact shape of the areas and are not intended to limit the scope of the claims.

“Group” means a group of the Periodic Table of the Elements according to the International Union of Pure and Applied Chemistry (“IUPAC”) Groups 1-18 grouping system.

Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents not currently contemplated or foreseen may occur to applicants or those skilled in the art. Accordingly, the appended claims, as filed and as modified, are intended to cover all such alternatives, modifications, variations, improvements and substantial equivalents.

Hereinafter, a solid ion conductor compound according to one or more exemplary embodiments, a solid electrolyte containing the same, an electrochemical cell containing the same, and a method of manufacturing the solid ion conductor compound will be described in more detail.

[Solid ion conductor compound]

The above-described solid ion conductor compound may include a compound represented by the following formula (1):

<Formula 1>

M _{3+m+(l-1)o+2p ( M} ^{' k +} _{) n}

In Formula 1, M may be one or more alkali metals.

According to one embodiment, M may include Li, Na, K, Rb, Cs, or a combination thereof. For example, M may include Li, Na, or a combination thereof.

According to one embodiment, M may include Li and Na. In this case, the molar ratio of Na/(Li+Na) may be less than 0.5. That is, when M further includes additional elements other than Li, the molar ratio of the additional elements may be smaller than the molar ratio of Li.

According to one embodiment, when a portion of Li is replaced with Na, the movement path of Li is expanded according to the expansion of the crystal lattice, and as a result, lithium ion conductivity is improved.

In Formula 1, M' may be one or more metals selected from divalent, trivalent, tetravalent, pentavalent, and hexavalent metals.

According to one embodiment, M' is Mg, Zn, Ca, Sr, Ba, Eu, Y, Gd, In, Er, La, Yb, Ce, Ho, Sn, Th, Nb, Mo, W, Sb, Bi , Zr, Hf, Ti, Si, or a combination thereof.

For example, M' may include Mg, Ca, Er, Sr, Ba, Y, Gd, Er, La, Ho, Zr, Hf, Ti, Ce, Si, or a combination thereof, but is limited thereto. It doesn't work.

In Formula 1, X may be one or more halogen elements.

According to one embodiment, X may be F, Cl, Br, I, or a combination thereof. For example, X may be Br, Cl, or a combination thereof, but is not limited thereto.

According to another embodiment, X may be Cl, and optionally, part of Cl may be replaced with Br. In this case, the molar ratio of Br/(Cl+Br) may be 0.5 or less. When the molar ratio of Br is lower than the molar ratio of Cl, excessive amorphization of the product can be suppressed, thereby preventing deterioration of ionic conductivity.

In Formula 1, T may be one or more monovalent or divalent anions.

For example, T may be NO ₃ ^- , CH ₃ COO ^- , OH ^- , HCO ₃ ^- , CrO ₄ ^2- , SO ₄ ^2- , CO ₃ ^2- , BH ₄ ^-, or a combination thereof, but is limited thereto. It doesn't work.

In Formula 1, Z may be one or more trivalent anions.

According to one embodiment, Z may include a trivalent monoatomic anion, a trivalent polyatomic anion, or a combination thereof. For example, Z may be a trivalent polyatomic anion.

According to one embodiment, Z is PO ₄ ^3- _, (C ₆ H ₅ O ₇ ) ^3- , PS ₄ ^3- _, [Fe(CN)] ^3- , [Ag(S ₂ O ₃ ) ₂ ] ^{3 -} , N ^3- , P ^3- or a combination thereof may be included.

For example, Z is PO ₄ ^3- _, (C ₆ H ₅ O ₇ ) ^3- , PS ₄ ^3- _, [Fe(CN)] ^3- , [Ag(S ₂ O ₃ ) ₂ ] ^3- , Or it may include a combination thereof, but is not limited thereto.

In Formula 1, 2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0 It may be <(3+m+kn-lo-3p+q).

The k refers to the cation valency of the M element, and may be, for example, 3≤k≤5.

The l refers to the anion valency of the T element and may be, for example, 1 or 2.

The m is a variable determined according to the initial input amount of the halide compound containing the raw material element M during the synthesis process, and may be, for example, -3≤m≤0.5.

Where n is the molar ratio of the M' element, for example, it may be 0.5≤n≤1.

The o is the molar ratio of the T element and may be, for example, 0.

The p is the molar ratio of the Z anion, for example, 0<p≤0.3, 0<p≤0.2, 0<p≤0.1, 0.01≤p≤0.3, 0.01≤p≤0.2, or 0.01≤p≤0.1. there is.

The q is a variable determined according to the initial input amount of the halide compound containing the raw material M' element during the synthesis process, and may be, for example, -3≤q≤0.5.

The 3+m+kn-lo-3p+q is the molar ratio of halide, for example, 5.8≤3+m+kn-lo-3p+q<6, or 5.9≤3+m+kn-lo-3p +q may be <6.

According to one embodiment, in Formula 1, 3+m+(l-1)o+2p is the molar ratio of M, and 2<3+m+(l-1)o+2p<3.

For example, 3+m+(l-1)o+2p may be 2<3+m+(l-1)o+2p<2.5.

When a solid ion conductor compound including the compound represented by the above-mentioned formula (1) satisfies the above-described composition, it can have improved lifespan characteristics and ionic conductivity.

According to one embodiment, Formula 1 may be represented by Formula 2 below.

<Formula 2>

(Li _1-h M _h ) _{3+m+(l-1)o+2p} ⁽ _{M ' k +} ⁾ _n ' _i ) _p

In Formula 2, refer to the above for information on M',

M is one or more alkali metals excluding Li,

Z' is one or more trivalent anions excluding PO ₄ ^3- ,

0≤h<1, 0≤i<1.

According to one embodiment, M may be Na.

According to one embodiment, h may satisfy 0≤h≤0.5 or 0.5≤h<1.

According to one embodiment, the i may satisfy 0≤i≤0.5 or 0.5≤i<1.

According to one embodiment, Formula 1 may be represented by Formula 3 below:

<Formula 3>

(Li _1-h M _h ) _{3+m+(l-1)o+2p (} ( ^Zr ) _{1 -j} M' _j ^k+ ) _n PO ₄ ) _1-i Z' _i ) _p

In Formula 3, please refer to the above for information on X, m, n, o, p, k, l, q and T,

M is one or more alkali metals excluding Li,

Z' is one or more trivalent anions excluding PO ₄ ^3- ,

M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals excluding Zr,

0≤j<1.

According to one embodiment, j may satisfy 0≤j≤0.5, or 0.5≤j≤1.

The above-mentioned solid ion conductor compound has diffraction angles 2θ=16°±0.5°, 20°±0.5°, 30°±0.5°, 32°±0.5°, 42°±0.5 and 50°± in the XRD spectrum using CuKα line. It may have a diffraction peak at 0.50.

According to one embodiment, as the content of the Z element in the solid ion conductor compound increases, the peak at the diffraction angle of 32°±0.5° may be shifted toward a lower diffraction angle.

According to one embodiment, the solid ion conductor compound may have increased a- and c-axis lattice constants compared to a compound that does not contain a trivalent anion represented by Z.

For example, the solid ion conductor compound may have a lattice constant increase of up to 0.01 Å along the a-axis and up to 0.015 Å along the c-axis compared to a compound that does not contain a trivalent anion represented by Z.

According to one embodiment, the solid ion conductor compound may have a crystalline phase, an amorphous phase, or a combination thereof, or may include an amorphous phase.

For example, the solid ion conductor compound may include a layered rock salt crystal structure in a crystalline phase. For example, the layered halite crystal structure may include a distorted layered halite crystal structure.

According to one embodiment, the solid ion conductor compound may include a crystal structure belonging to the P3-m1 space group in a crystal phase.

According to one embodiment, the solid ion conductor compound may have an ionic conductivity of 3.0 x 10 ^-4 S/cm or more at room temperature, for example, 25°C. For example, the solid ion conductor compound is 3.2 x 10 ^-4 S/cm or more, 4.0 x 10 ^-4 S/cm or more, 5.0 x 10 ^-4 S/cm or more, 6.0 x 10 ^-4 S/ at 25°C. cm or more, 7.0 x 10 ^-4 S/cm or more, 8.0 x 10 ^-4 S/cm or more, 9.0 x 10 ^-4 S/cm or more, or 1.0 x 10 ^-3 S/cm or more.

According to one embodiment, the solid ion conductor compound is 3.0 x 10 ^-4 S/cm to 5.0 x 10 ^-1 S/cm, 5.0 x 10 ^-4 S/cm to 3.0 x 10 ^-1 S/cm at 25°C. , it may have an ionic conductivity of 7.0 x 10 ^-4 S/cm to 1.0 x 10 ^-1 S/cm.

According to one embodiment, the solid ion conductor compound is Li _2.1 ZrCl _5.95 (PO ₄ ) _0.05 , Li _2.02 ZrCl _5.99 (PO ₄ ) _0.01 , Li _2.04 ZrCl _5.98 (PO ₄ ) _0.02 , Li _2.08 ZrCl _5.96 (PO ₄ ) _0.04 , Li _2.12 ZrCl _5.94 (PO ₄ ) _0.06 , Li _2.2 ZrCl _5.9 (PO ₄ ) _0.1 , Li _2.15 Zr _0.8 Y _0.2 Cl _5.95 (PO ₄ ) _0.05 , Li _2.45 Zr _0.5 Y _0.5 Cl _5.95 (PO ₄ ) _0.05 , Li _2.22 ZrCl _5.89 (PO ₄ ) _0.11 , Li _2.24 ZrCl _5.88 (PO ₄ ) _0.12 , It may be Li _2.3 ZrCl _5.85 (PO ₄ ) _0.15, Li _2.4 ZrCl _5.8 (PO ₄ ) _0.2 , Li _2.6 ZrCl _5.7 (PO ₄ ) _0.3 or Li _2.1 ZrCl _5.95 (PS ₄ ) _0.05 .

[Method for producing solid ion conductor compounds]

A method for producing a solid ion conductor compound according to one aspect includes preparing a mixture containing an M element-containing halide compound, an M' element-containing halide compound, and a Z element-containing compound, and reacting the mixture in a solid phase. obtaining a solid ion conductor compound; wherein the M element is one or more alkali metals, and the M' element is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals. , the Z element is one or more trivalent anions. Here, the solid ion conductor compound is the solid ion conductor compound described above.

The M element-containing halide compound may include lithium halide. For example, lithium halide may include LiF, LiCl, LiBr, LiI, or combinations thereof. For example, the lithium halide may include LiCl, LiBr, or a combination thereof.

The halide compound containing the M' element is a halide of divalent, trivalent, tetravalent, pentavalent and hexavalent metals, and may include, for example, zirconium halide and yttrium halide. For example, zirconium halides are ZrF ₄ , ZrCl ₄ . It includes ZrBr ₄ , ZrI ₄ , or a combination thereof, and the yttrium halide may include YF ₃ , YCl ₃ , YBr ₃ , YI ₃ , or a combination thereof. For example, the zirconium halide may include ZrCl ₄ , ZrBr ₄ , or a combination thereof, and the yttrium halide may include YCl ₃ , YBr ₃ , or a combination thereof.

The Z element-containing compound may include a lithium precursor compound containing a -3 valent anion. For example, compounds containing element Z are Li ₃ PO _4, Li ₃ (C ₆ H ₅ O ₇ ), Li ₃ PS _4, Li ₃ [Fe(CN)], Li ₃ [Ag(S ₂ O ₃ ) ₂ ], Li ₃ N, Li ₃ P, or a combination thereof.

According to one embodiment, the halide compound containing the M element and the halide compound containing the M' element may be mixed in a stoichiometric ratio of 1.8:1 or more and less than 2:1. For example, the halide compound containing the M element and the halide compound containing the M' element have a stoichiometric ratio of 1.8:1 to 1.99:1, 1.8:1 to 1.98:1, 1.8:1 to 1.97:1, and 1.8:1 to 1.96. :1 or 1.8:1 to 1.95:1, but is not limited thereto.

According to one embodiment, the step of reacting the mixture in a solid phase to obtain a solid ion conductor compound may include drying the mixture and performing ball mill mixing at 400 rpm for 48 hours in an inert atmosphere. The dry and inert atmosphere may be an Ar atmosphere or a nitrogen atmosphere.

According to one embodiment, the ball mill mixing may be performed for a first period, followed by a rest period for a second period. Here, the first period and the second period may be the same or different from each other. For example, the first period may be at least twice as long as the second period, for example, three times as long. In this way, a solid ion conductor compound with improved ionic conductivity can be obtained by providing a rest period during the ball mill mixing process.

According to one implementation, the first period may be 10 to 20 minutes. For example, the first period may be 12 to 18 minutes, or 15 minutes.

According to one implementation, the second period may be 3 minutes to 10 minutes. For example, it may be 3 to 7 minutes or 5 minutes. According to one embodiment, the ball mill mixing is performed at a first time interval, the ball mill mixing further includes a rest period after the first time interval, and the time interval and the rest period may be repeated.

According to one embodiment, the method for producing the solid ion conductor compound is performed at room temperature and does not include a calcination step for crystallization. For example, the method for producing the solid ion conductor compound may be performed at room temperature (25°C).

A general method for producing a solid ion conductor compound includes the step of mixing raw materials and then heat treating them to crystallize them. However, the method for producing a solid ion conductor compound of the present invention may not include a separate crystallization step after the solid phase mixing step. In one implementation, a separate crystallization step may be omitted. As a result, not only is the manufacturing method simple, but it is also possible to prevent deformation of the material structure due to sintering, so that a solid ion conductor compound with a target composition and crystal structure and improved ionic conductivity can be obtained.

The inert atmosphere is an atmosphere containing an inert gas. The inert gas is, for example, nitrogen, argon, etc., but is not necessarily limited to these, and any inert gas that is used in the relevant technical field can be used.

[Electrochemical cell]

An electrochemical cell according to another embodiment includes a positive electrode layer including a positive electrode active material layer; A negative electrode layer including a negative electrode active material layer; and a solid electrolyte layer interposed between the anode layer and the cathode layer, wherein at least one of the anode layer and the solid electrolyte layer may include the solid ion conductor compound described above. As the electrochemical cell includes the solid ion conductor compound, the lithium ion conductivity and chemical stability of the electrochemical cell are improved.

The electrochemical cell may be, for example, an all-solid secondary battery, a secondary battery containing a liquid electrolyte, or a lithium-air battery, but is not necessarily limited to these, and any electrochemical cell that can be used in the relevant technical field can be used.

Below, an all-solid-state secondary battery will be described by way of example.

[All-solid-state secondary battery: Type 1]

It may include the solid ion conductor compound described above.

All-solid-state secondary batteries include, for example, a positive electrode layer including a positive electrode active material layer; A negative electrode layer including a negative electrode active material layer; and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and at least one of the positive electrode active material layer and the solid electrolyte layer may include the solid ion conductor compound described above.

An all-solid-state secondary battery according to one embodiment can be prepared as follows.

(Solid electrolyte layer)

First, a solid electrolyte layer is prepared.

The solid electrolyte layer can be manufactured by mixing and drying the above-mentioned solid ion conductor compound and a binder, or by rolling the powder of the solid ion conductor compound represented by Formula 1 into a certain shape at a pressure of 1 ton to 10 tons. The above-described solid ion conductor compound is used as a solid electrolyte.

The average particle diameter of the solid electrolyte may be, for example, 0.5 μm to 20 μm. When the solid electrolyte has such an average particle size, cohesion is improved during the sintered body formation process, and the ionic conductivity and lifespan characteristics of the solid electrolyte particles can be improved.

The thickness of the solid electrolyte layer may be 10um to 200um. When the solid electrolyte layer has this thickness, a sufficient movement speed of lithium ions is guaranteed and, as a result, high ionic conductivity can be obtained.

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 solid ion conductor compound described above.

Conventional sulfide-based solid electrolytes may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or a combination thereof. Conventional sulfide-based solid electrolyte particles may include Li ₂ S, P ₂ S ₅ , SiS ₂ , GeS ₂ , B ₂ S ₃ or a combination thereof. Conventional sulfide-based solid electrolyte particles may be Li ₂ S or P ₂ S ₅ . Conventional sulfide-based solid electrolyte particles are known to have higher lithium ion conductivity than other inorganic compounds. For example, a conventional sulfide-based solid electrolyte includes Li ₂ S and P ₂ S ₅ . When the sulfide solid electrolyte material constituting the conventional sulfide-based solid electrolyte includes Li ₂ SP ₂ S ₅ , the mixing molar ratio of Li ₂ S to P ₂ S ₅ is, for example, about 50:50 to about 90:10. It may be a range. In addition, Li ₃ PO ₄ , halogen, halogen compound, Li _2+2x Zn _1-x GeO ₄ (“LISICON”; 0<x<1), Li _3+y PO _4-x N _{x (} “LIPON”; - 3<y<3, 0<x<4), Li _3.25 Ge _0.25 P _0.75 S ₄ ("ThioLISICON"), Li ₂ O-Al ₂ O ₃ -TiO ₂ -P ₂ O _{5 (} "LATP"), etc. An inorganic solid electrolyte prepared by adding Li ₂ SP ₂ S ₅ , SiS ₂ , GeS ₂ , B ₂ S ₃ , or a combination thereof to an inorganic solid electrolyte can be used as a conventional sulfide solid electrolyte. Non-limiting examples of conventional sulfide solid electrolyte materials include Li ₂ SP ₂ S ₅ ; Li ₂ SP ₂ S ₅ -LiX (X is a halogen element); Li ₂ SP ₂ S ₅ -Li ₂ O; Li ₂ SP ₂ S ₅ -Li ₂ O-LiI; Li ₂ S-SiS ₂ ; Li ₂ S-SiS ₂ -LiI; Li ₂ S-SiS ₂ -LiBr; Li ₂ S-SiS ₂ -LiCl; Li ₂ S-SiS ₂ -B ₂ S ₃ -LiI; Li ₂ S-SiS ₂ -P ₂ S ₅ -LiI; Li ₂ SB ₂ S ₃ ; Li ₂ S -P ₂ S ₅ -Z _m S _n (m and n are positive numbers and Z is Ge, Zn or G); Li ₂ S-GeS ₂ ; Li ₂ S-SiS ₂ -Li ₃ PO ₄ ; and Li ₂ S-SiS ₂ -Li _p MO _q (where p and q are positive numbers and M is P, Si, Ge, B, Al, Ga or In). In this regard, the conventional sulfide-based solid electrolyte material is a raw material starting material for the sulfide-based solid electrolyte material (e.g., Li ₂ S, P ₂ S ₅ , etc.) using a melt quenching method or a mechanical milling method. It can be manufactured by processing by etc. Additionally, calcinations can be performed after the treatment.

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

(anode layer)

Next, the anode layer is prepared.

The positive electrode layer can be manufactured by forming a positive electrode active material layer containing a positive electrode active material on a current collector. The average particle diameter of the positive electrode active material may be, for example, 2 μm to 10 μm.

Any cathode active material can be used without limitation as long as it is commonly used in secondary batteries. For example, it may be lithium transition metal oxide, transition metal sulfide, etc. For example, one or more types of complex oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

Specific examples of the positive electrode active material include Li _a A _1-b B ¹ _b D ¹ ₂ (in the above formula, 0.90 ≤ a ≤ 1.8, and 0 ≤ b ≤ 0.5); Li _a E _1-b B ¹ _b O _2-c D ¹ _c (in the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE _2-b B ¹ _b O _4-c D ¹ _c (in the above formula, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li _a Ni _1-bc Co _b B ¹ _c D ¹ _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li _a Ni _1-bc Co _b B ¹ _c O _2-α F ¹ _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Co _b B ¹ _c O _2-α F ¹ _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Mn _b B ¹ _c D ¹ _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li _a Ni _1-bc Mn _b B ¹ _c O _2-α F ¹ _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Mn _b B ¹ _c O _2-α F ¹ ₂ (in the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _b E _c G _d O ₂ (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li _a Ni _b Co _c Mn _d GeO ₂ (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1); Li _a NiG _b O ₂ (in the above formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li _a CoG _b O ₂ (in the above formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li _a MnG _b O ₂ (in the above formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li _a Mn ₂ G _b O ₄ (in the above formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); QO ₂ ; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₂ ; LiIO ₂ ; LiNiVO ₄ ; Li _(3-f) J ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); There are compounds expressed in any one of the chemical formulas of LiFePO ₄ . In the above formula, A is Ni, Co, Mn, or a combination thereof; B ¹ Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D ¹ O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F ¹ 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; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. For example, LiCoO ₂ , LiMn _x O _2x (x=1, 2), LiNi _1-x Mn _x O _2x (0<x<1), Ni _1-xy Co _x Mn _y O ₂ (0≤x≤ _{0.5 , 0≤y≤0.5 ) , Ni 1 - xy Co} am.

It is also possible to use a compound to which a coating layer is added to the surface of such a compound, and it is also possible to use a mixture of the above-described compound and a compound to which a coating layer is added. The coating layer added to the surface of such a compound includes, for example, a coating element compound of an oxide, hydroxide, oxyhydroxide of the coating element, oxycarbonate of the coating element, or hydroxycarbonate of the coating element. The compounds that make up this coating layer are amorphous or crystalline. Coating elements included in the coating layer include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The method of forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. Coating methods include, for example, spray coating, dipping method, etc. Since the specific coating method is well understood by those working in the field, detailed explanation will be omitted.

The positive electrode active material includes, for example, a lithium salt of the above-described lithium transition metal oxide having a layered rock salt type structure. “Layered rock salt type structure” is, for example, a cubic rock salt type structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in the <111> direction, whereby each atomic layer forms a two-dimensional plane. It is a structure that forms a . “Cubic rock salt type structure” refers to a sodium chloride type (NaCl type) structure, which is a type of crystal structure. Specifically, the face centered cubic lattice (fcc) formed by cations and anions, respectively, forms a unit lattice. ) indicates a structure arranged offset by 1/2 of the ridge. The lithium transition metal oxide having this layered rock salt structure is, for example, LiNi _x Co _y Al _z O ₂ (NCA) (0 < x < 1, 0 < y < 1, 0 < z < 1, x + y + z = 1) or LiNi _x' Co _y' Mn _z' O ₂ (NCM) (0 <x'< 1, 0 <y'< 1, 0 <z'< 1, x' + y' + z' = 1) and other ternary lithium transition metal oxides. When the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt-type structure, the energy density and thermal stability of the all-solid-state secondary battery 1 are further improved.

According to one embodiment, the positive electrode layer includes a positive electrode active material represented by LiNi _x Co _y Al _z O ₂ or LiNi _x' Co _y' Mn _z' O ₂ , where 0 < x < 1, 0 < y < 1, 0 < z < 1, x + y + z = 1, 0 <x'< 1, 0 <y'< 1, 0 <z'< 1, x' + y' + z' = 1, Some or all of the surface of the positive electrode active material may be coated with the above-mentioned solid ion conductor compound, and additionally, a known lithium ion conductor compound, for example, Li ₂ ZrO ₃ or Li ₂ O-ZrO ₂ (LZO) compound. Can be coated.

If the cathode active material contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, it is possible to increase the capacity density of the all-solid-state secondary battery and reduce metal elution from the cathode active material in the charged state. . As a result, the cycle characteristics of the all-solid-state secondary battery in the charged state are improved.

The shape of the positive electrode active material is, for example, a particle shape such as a sphere, an elliptical sphere, or the like. The particle size of the cathode active material is not particularly limited and is within the range applicable to the cathode active material of conventional all-solid-state secondary batteries. The content of the positive electrode active material in the positive electrode layer is also not particularly limited, and is within a range applicable to the positive electrode layer of a conventional all-solid-state secondary battery. The content of the positive electrode active material in the positive electrode active material layer may be, for example, 50 to 95% by weight.

The positive electrode active material layer may additionally include the solid ion conductor compound described above.

The positive electrode active material layer may include a binder. The binder is, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc.

The positive electrode active material layer may include a conductive material. Conductive materials include, for example, graphite, carbon black, carbon nanotubes (CNF), acetylene black, Ketjen black, carbon fiber, metal powder, etc.

In addition to the positive electrode active material, solid ion conductor, binder, and conductive material described above, the positive electrode active material layer may further include additives such as filler, coating agent, dispersant, and ion conductivity auxiliary agent.

As fillers, coating agents, dispersants, ion conductive auxiliaries, etc. that the positive electrode active material layer may contain, known materials generally used in electrodes of all-solid-state secondary batteries can be used.

The positive electrode current collector is, for example, aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), A plate or foil made of zinc (Zn), germanium (Ge), lithium (Li), or an alloy thereof is used. The positive electrode current collector can be omitted.

The positive electrode current collector may further include a carbon layer disposed on one or both sides of the metal substrate. By additionally disposing a carbon layer on the metal substrate, the metal of the metal substrate can be prevented from being corroded by the solid electrolyte contained in the positive electrode layer and the interfacial resistance between the positive electrode active material layer and the positive electrode current collector can be reduced. The thickness of the carbon layer may be, for example, 1um to 5um. If the thickness of the carbon layer is too thin, it may be difficult to completely block contact between the metal substrate and the solid electrolyte. If the thickness of the carbon layer is too thick, the energy density of the all-solid-state secondary battery may decrease. The carbon layer may include amorphous carbon, crystalline carbon, etc.

(Cathode layer)

Next, the cathode layer is prepared.

The negative electrode layer can be manufactured in the same manner as the positive electrode layer, except that the negative electrode active material is used instead of the positive electrode active material. The negative electrode layer can be manufactured by forming a negative electrode active material layer containing a negative electrode active material on a negative electrode current collector.

The negative electrode active material layer may additionally include the solid ion conductor compound described above.

The negative electrode active material may be lithium metal, lithium metal alloy, or a combination thereof.

The negative electrode active material layer may further include a conventional negative electrode active material in addition to lithium metal, lithium metal alloy, or a combination thereof. Conventional negative active materials may include, for example, one or more selected from the group consisting of metals alloyable with lithium, transition metal oxides, non-transition metal oxides, and carbon-based materials. Metals that can be alloyed with lithium include, for example, Ag, Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloy (where Y is an alkali metal, alkaline earth metal, Group 13 element, Group 14 element, transition metal, rare earth) element or a combination thereof, but not Si), Sn-Y alloy (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, but not Sn) ), etc. The element Y includes Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, It may be Se, Te, Po, or a combination thereof. The transition metal oxide may be, for example, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc. Non-transition metal oxides may be, for example, SnO ₂ , SiO _x (0<x<2), etc. The carbon-based material may be, for example, crystalline carbon, amorphous carbon, or mixtures thereof. Crystalline carbon may be graphite such as amorphous, plate-shaped, flake, spherical or fibrous natural graphite or artificial graphite, and the amorphous carbon may be soft carbon (low-temperature sintered carbon) or hard carbon. ), mesophase pitch carbide, calcined coke, etc.

Referring to FIG. 7, the all-solid-state secondary battery 1 according to one embodiment includes a solid electrolyte layer 30, a positive electrode layer 10 disposed on one side of the solid electrolyte layer 30, and a solid electrolyte layer 30. It includes a cathode layer 20 disposed on the other side. The positive electrode layer 30 includes a positive electrode active material layer 12 in contact with the solid electrolyte layer 30 and a positive electrode current collector 11 in contact with the positive electrode active material layer 12, and the negative electrode layer 20 includes a solid electrolyte layer 30. ) and a negative electrode current collector 21 in contact with the negative electrode active material layer 22 and the negative electrode active material layer 22. For example, the all-solid-state secondary battery 1 includes applying a positive electrode active material layer 12 to the first side of the solid electrolyte layer 30 and applying a negative electrode active material layer 22 to the second side of the solid electrolyte layer 30. Apply to form a positive electrode active material layer 12 and a negative electrode active material layer 22, and form a positive electrode current collector 11 and a negative electrode current collector 21 on the positive electrode active material layer 12 and the negative electrode active material layer 22, respectively. It is completed by doing so. Alternatively, the all-solid secondary battery 1 includes, for example, a negative electrode active material layer 22, a solid electrolyte layer 30, a positive electrode active material layer 12, and a positive electrode current collector 11 on the negative electrode current collector 21. It is completed by sequentially layering.

The positive electrode layer and solid electrolyte layer are manufactured in the same manner as the all-solid secondary battery described above.

The negative electrode layer 20 includes a negative electrode current collector 21 and a negative electrode active material layer 22 disposed on the negative electrode current collector 21, and the negative electrode active material layer 22 includes, for example, a negative electrode active material and a binder. .

The negative electrode active material included in the negative electrode active material layer 22 has, for example, the form of particles. The average particle diameter of the negative electrode active material in particle form is, for example, 4 um or less, 3 um or less, 2 um or less, 1 um or less, or 900 nm or less. The average particle diameter of the negative electrode active material in particle form is, for example, 10nm to 4um or less, 10nm to 3um or less, 10nm to 2um or less, 10nm to 1um or less, or 10nm to 900nm or less. Because the negative electrode active material has an average particle size in this range, reversible absorption and/or desorbing of lithium can be facilitated more easily during charging and discharging. The average particle diameter of the negative electrode active material is, for example, the median diameter (D50) measured using a laser particle size distribution meter.

The negative electrode active material included in the negative electrode active material layer 22 includes, for example, one or more selected from carbon-based negative electrode active materials and metal or metalloid negative electrode active materials.

The carbon-based negative electrode active material is particularly amorphous carbon. Amorphous carbon is, for example, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene. ), etc., but is not necessarily limited to these, and any carbon that is classified as amorphous carbon in the relevant technical field is possible. Amorphous carbon is carbon that does not have crystallinity or has very low crystallinity and is distinguished from crystalline carbon or graphitic carbon (eg, graphite).

Metal or metalloid anode active materials include 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 negative active material or metalloid negative electrode active material that forms an alloy or compound with lithium in the art can be used. For example, nickel (Ni) does not form an alloy with lithium, so it is not a metal anode active material.

The negative electrode active material layer 22 includes a type of negative electrode active material among these negative electrode active materials, or a mixture of a plurality of different negative electrode active materials. For example, the negative electrode active material layer 22 contains only amorphous carbon, or gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), and bismuth (Bi). ), tin (Sn), and zinc (Zn). Alternatively, the negative electrode active material layer 22 is made of amorphous carbon, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), and tin ( It includes a mixture with one or more selected from the group consisting of Sn) and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold, etc. is a weight ratio, for example, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1, but is not necessarily limited to these ranges and may vary depending on the required amount. It is selected according to the characteristics of the solid secondary battery (1). When the negative electrode active material has this composition, the cycle characteristics of the all-solid-state secondary battery 1 are further improved.

The negative electrode active material included in the negative electrode active material layer 22 includes, for example, a mixture of first particles made of amorphous carbon and second particles made of metal or metalloid. Metals or metalloids include, for example, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), and tin (Sn). ) and zinc (Zn). Metalloids, on the other hand, are semiconductors. The content of the second particles is 8 to 60%, 10 to 50%, 15 to 40%, or 20 to 30% by weight, based on the total weight of the mixture. By having the content of the second particles in this range, for example, the cycle characteristics of the all-solid-state secondary battery 1 are further improved.

The binder included in the negative electrode active material layer 22 is, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride/ It is not necessarily limited to hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., and any binder used in the art can be used. The binder may be single or composed of multiple different binders.

As the negative electrode active material layer 22 includes a binder, the negative electrode active material layer 22 is stabilized on the negative electrode current collector 21. In addition, cracking of the negative electrode active material layer 22 is suppressed despite changes in the volume and/or relative position of the negative electrode active material layer 22 during the charging and discharging process. For example, when the negative electrode active material layer 22 does not include a binder, it is possible for the negative electrode active material layer 22 to be easily separated from the negative electrode current collector 21. A short circuit may occur when the negative electrode current collector 21 comes into contact with the solid electrolyte layer 30 in the exposed portion of the negative electrode current collector 21 due to the separation of the negative electrode active material layer 22 from the negative electrode current collector 21. The likelihood increases. The negative electrode active material layer 22 is manufactured, for example, by applying a slurry in which the material constituting the negative electrode active material layer 22 is dispersed onto the negative electrode current collector 21 and drying it. By including a binder in the negative electrode active material layer 22, stable dispersion of the negative electrode active material in the slurry is possible. For example, when the slurry is applied onto the negative electrode current collector 21 by screen printing, it is possible to suppress clogging of the screen (for example, clogging by aggregates of the negative electrode active material).

The negative electrode active material layer 22 may further include additives used in the conventional all-solid-state secondary battery 1, such as fillers, coating agents, dispersants, and ion conductive auxiliaries.

The thickness of the negative electrode active material layer 22 is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer 12. The thickness of the negative electrode active material layer 22 is, for example, 1 μm to 20 μm, 2 μm to 10 μm, or 3 μm to 7 μm. If the thickness of the negative electrode active material layer 22 is too thin, the lithium dendrites formed between the negative electrode active material layer 22 and the negative electrode current collector 21 collapse the negative electrode active material layer 22, causing the all-solid-state secondary battery (1) It is difficult to improve the cycle characteristics of If the thickness of the negative electrode active material layer 22 increases excessively, the energy density of the all-solid-state secondary battery 1 decreases and the internal resistance of the all-solid secondary battery 1 due to the negative electrode active material layer 22 increases, thereby reducing the all-solid-state secondary battery. It is difficult to improve the cycle characteristics of (1).

If the thickness of the negative electrode active material layer 22 decreases, for example, the charging capacity of the negative electrode active material layer 22 also decreases. For example, the charge capacity of the negative electrode active material layer 22 is 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% compared to the charge capacity of the positive electrode active material layer 12. It is as follows. The charging capacity of the negative electrode active material layer 22 is, for example, 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% compared to the charging capacity of the positive electrode active material layer 12. to 10%, 0.1% to 5%, or 0.1% to 2%. If the charge capacity of the negative electrode active material layer 22 is too small, the thickness of the negative electrode active material layer 22 becomes very thin, so lithium formed between the negative electrode active material layer 22 and the negative electrode current collector 21 during repeated charging and discharging processes. Dendrites collapse the negative electrode active material layer 22, making it difficult to improve the cycle characteristics of the all-solid-state secondary battery 1. If the charging capacity of the negative electrode active material layer 22 is excessively increased, the energy density of the all-solid-state secondary battery 1 decreases and the internal resistance of the all-solid secondary battery 1 due to the negative electrode active material layer 22 increases, resulting in an all-solid secondary battery 1. It is difficult to improve the cycle characteristics of the battery 1.

The charge capacity of the positive electrode active material layer 12 is obtained by multiplying the charge capacity density (mAh/g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer 12. When multiple types of positive electrode active materials are used, the charging capacity density × mass value is calculated for each positive electrode active material, and the sum of these values is the charging capacity of the positive electrode active material layer 12. The charging capacity of the negative electrode active material layer 22 is also calculated in the same way. That is, the charge capacity of the negative electrode active material layer 22 is obtained by multiplying the charge capacity density (mAh/g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer 22. When several types of negative electrode active materials are used, the charge capacity density × mass value is calculated for each negative electrode active material, and the sum of these values is the capacity of the negative electrode active material layer 22. Here, the charging capacity density of the positive electrode active material and the negative electrode active material is the capacity estimated using an all-solid half-cell using lithium metal as a counter electrode. By measuring the charge capacity using an all-solid half-cell, the charge capacity of the positive electrode active material layer 12 and the negative electrode active material layer 22 are directly measured. By dividing the measured charging capacity by the mass of each active material, the charging capacity density is obtained. Alternatively, the charge capacity of the positive electrode active material layer 12 and the negative electrode active material layer 22 may be the initial charge capacity measured during the first charging cycle.

[All-solid-state secondary battery: Type 2]

Referring to FIG. 8, the all-solid-state secondary battery 1a includes, for example, a positive electrode layer 10 including a positive electrode active material layer 12 disposed on a positive electrode current collector 11; A negative electrode layer 20 including a negative electrode active material layer 22 disposed on the negative electrode current collector 21; and an electrolyte layer 30 disposed between the positive electrode layer 10 and the negative electrode layer 20, where the positive electrode active material layer 12 and/or the electrolyte layer 30 may include the solid ion conductor compound described above. there is. The all-solid-state secondary battery 1a may further include, for example, a metal layer 23 disposed between the negative electrode current collector 21 and the negative electrode active material layer 22. The metal layer 23 includes lithium or a lithium alloy.

An all-solid-state secondary battery according to another embodiment can be prepared as follows.

The positive electrode layer and solid electrolyte layer are manufactured in the same manner as the all-solid secondary battery described above.

Referring to FIG. 8, in the all-solid secondary battery 1a, the metal layer 23 is, for example, disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 before assembly of the all-solid secondary battery 1, or After assembly of the solid secondary battery 1, it is deposited between the negative electrode current collector 21 (21, 21a, 21b) and the negative electrode active material layer 22 by charging. When the metal layer 23 is disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 before assembly of the all-solid-state secondary battery 1a, the metal layer 23 is a metal layer containing lithium and thus acts as a lithium reservoir. It acts as For example, before assembly of the all-solid-state secondary battery 1a, lithium foil is placed between the negative electrode current collector 21 and the negative electrode active material layer 22.

The metal layer 23 may include a lithium alloy and, for example, acts as a lithium reservoir. Lithium alloys include, for example, Li-Al alloy, Li-Sn alloy, Li-In alloy, Li-Ag alloy, Li-Au alloy, Li-Zn alloy, Li-Ge alloy, Li-Si alloy, etc. It is not limited to, and any lithium alloy used in the relevant technical field is possible. The metal layer 23 may be made of one of these alloys or lithium, or may be made of several types of alloys.

The thickness of the metal layer 23 is not particularly limited, but is, for example, 1 μm to 1000 μm, 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 150 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the metal layer 23 is too thin, it is difficult for the metal layer 23 to function as a lithium reservoir. If the thickness of the metal layer 23 is too thick, the mass and volume of the all-solid-state secondary battery 1a may increase and cycle characteristics may deteriorate. The metal layer 23 may be, for example, a metal foil with a thickness in this range.

The cycle characteristics of the all-solid-state secondary battery 1a including the metal layer 23 are further improved. When the metal layer 23 is precipitated by charging after assembly of the all-solid-state secondary battery 1a, the energy of the all-solid-state secondary battery 1a is reduced because the metal layer 23 is not included during assembly of the all-solid-state secondary battery 1a. Density increases. For example, when charging the all-solid-state secondary battery 1a, the charge exceeds the charging capacity of the negative electrode active material layer 22. That is, the negative electrode active material layer 22 is overcharged. At the beginning of charging, lithium is stored in the negative electrode active material layer 22. The negative electrode active material included in the negative electrode active material layer 22 forms an alloy or compound with lithium ions that have migrated from the positive electrode layer 10. When charging exceeds the capacity of the negative electrode active material layer 22, for example, lithium is precipitated on the back of the negative electrode active material layer 22, that is, between the negative electrode current collector 21 and the negative electrode active material layer 22, and the precipitated A metal layer corresponding to the metal layer 23 is formed by lithium. The metal layer 23 is a metal layer mainly composed of lithium (i.e., metallic lithium). This result is obtained, for example, when the negative electrode active material included in the negative electrode active material layer 22 is composed of a material that forms an alloy or compound with lithium. During discharge, the lithium in the negative electrode active material layer 22 and the metal layer 23, that is, the metal layer, is ionized and moves toward the positive electrode layer 10. Therefore, it is possible to use lithium as a negative electrode active material in the all-solid-state secondary battery 1a. In addition, since the negative electrode active material layer 22 covers the metal layer 23, it serves as a protective layer for the metal layer 23 and at the same time suppresses the precipitation growth of lithium dendrites. Therefore, short-circuiting and capacity reduction of the all-solid-state secondary battery 1a are suppressed, and as a result, the cycle characteristics of the all-solid-state secondary battery 1a are improved. In addition, when the metal layer 23 is disposed by charging after assembly of the all-solid-state secondary battery 1a, the negative electrode current collector 21 and the negative electrode active material layer 22 and the area between them are, for example, an all-solid secondary battery. (1a) is a Li-metal free region that does not contain lithium (Li) in the initial state or the state after discharge.

The negative electrode current collector 21 is made of a material that does not react with lithium, that is, does not form any alloy or compound. Materials constituting the negative electrode current collector 21 include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but are not necessarily limited to these. Anything that can be used as an electrode current collector in the technical field is possible. The negative electrode current collector 21 may be composed of one of the above-described metals, an alloy of two or more metals, or a coating material. The negative electrode current collector 21 is, for example, in the form of a plate or foil.

The all-solid-state secondary battery 1a may further include, for example, a thin film (not shown) containing an element capable of forming an alloy with lithium on the negative electrode current collector 21. The thin film is disposed between the negative electrode current collector 21 and the negative electrode active material layer 22. The thin film contains elements that can form alloys, for example with lithium. Elements that can form an alloy with lithium include, for example, gold, silver, zinc, tin, indium, silicon, aluminum, and bismuth, but are not necessarily limited to these, and elements that can form an alloy with lithium are known in the art. Any element is possible. The thin film is composed of one of these metals or an alloy of several types of metals. By placing the thin film on the negative electrode current collector 21, for example, the precipitation form of the metal layer 23 deposited between the thin film and the negative electrode active material layer 22 is further flattened, and the cycle of the all-solid-state secondary battery 1a is improved. The characteristics can be further improved.

The thickness of the thin film is, for example, 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. If the thickness of the thin film is less than 1 nm, it may be difficult for the thin film to function. If the thickness of the thin film is too thick, the thin film itself may occlude lithium, which may reduce the amount of lithium precipitated at the negative electrode, thereby lowering the energy density of the all-solid-state battery and deteriorating the cycle characteristics of the all-solid-state secondary battery 1a. The thin film may be disposed on the negative electrode current collector 21 by, for example, vacuum deposition, sputtering, plating, etc., but it is not necessarily limited to these methods and any method that can form a thin film in the art is possible.

This creative idea is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the creative idea, and the scope of the creative idea is not limited to these alone.

(Manufacture of solid ion conductor compound)

Example 1

In a glove box in an Ar atmosphere, ZrCl ₄ as a halide compound containing the M' element, LiCl as a halide compound containing the M element, and Li ₃ (PO ₄ ) as a compound containing the Z element were mixed at a stoichiometric ratio of 1:1.95:0.05. After putting it into a planetary ball mill and adding zirconia (YSZ) balls, grinding and mixing for 15 minutes at 400 rpm in Ar atmosphere, the cycle with a rest period of 5 minutes is repeated for 48 hours. Thus, a solid ion conductor compound with the composition shown in Table 1 was obtained. Next, for XRD analysis, the obtained solid ion conductor compound was pressed at a uniaxial pressure of 350 MPa to prepare a pellet with a thickness of about 10 mm and a diameter of about 13 mm.

Example 2

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.99:0.01, and the mixture was molded to prepare a pellet.

Example 3

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.98:0.02, and the mixture was molded to prepare a pellet.

Example 4

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.96:0.04, and a pellet was prepared by molding it.

Example 5

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.94:0.06, and the mixture was molded to prepare a pellet.

Example 6

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.9:0.1, and the mixture was molded to prepare a pellet.

Example 7

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, Li ₃ (PO ₄ ), and YCl ₃ were mixed at a stoichiometric ratio of 0.8:1.95:0.05:0.2, and it was molded into pellets. prepared.

Example 8

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, Li ₃ (PO ₄ ), and YCl ₃ were mixed at a stoichiometric ratio of 0.8:1.95:0.05:0.2, and it was molded into pellets. prepared.

Example 9

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PS ₄ ) were mixed at a stoichiometric ratio of 1:1.95:0.05, and a pellet was prepared by molding it.

Example 10

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.89:0.11, and a pellet was prepared by molding it.

Example 11

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.88:0.12, and a pellet was prepared by molding it.

Example 12

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.85:0.15, and pellets were prepared by molding the mixture.

Example 13

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.8:0.2, and a pellet was prepared by molding it.

Example 14

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PS ₄ ) were mixed at a stoichiometric ratio of 1:1.7:0.3, and a pellet was prepared by molding it.

Comparative Example 1

A solid ion conductor compound with the composition shown in Table 1 was obtained using the same method as in Example 1, except that ZrCl ₄ and LiCl were used as raw materials at a stoichiometric ratio of 1:2, and pellets were prepared by molding them.

Comparative Example 2

A solid ion conductor compound with the composition shown in Table 1 was obtained using the same method as in Example 1, except that YCl ₃ and LiCl were used as raw materials at a stoichiometric ratio of 1:3, and pellets were prepared by molding them.

Comparative Example 3

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₂ O were mixed at a stoichiometric ratio of 1:1.95:0.05, and a pellet was prepared by molding it.

Comparative Example 4

A solid ion conductor compound was obtained in the same manner as in Example 1, except that YCl ₃ , LiCl, and Li ₂ O were mixed at a stoichiometric ratio of 1:2.95:0.05, and a pellet was prepared by molding it.

Comparative Example 5

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₂ (SO ₄ ) were mixed at a stoichiometric ratio of 1:1.95:0.05, and a pellet was prepared by molding it.

Comparative Example 6

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and LiNO ₃ were mixed at a stoichiometric ratio of 1:1.95:0.05, and it was molded to prepare a pellet.

Comparative Example 7

A solid ion conductor compound was obtained in the same manner as in Example 1, except that ZrCl ₄ , LiCl, and Li ₃ (PO ₄ ) were mixed at a stoichiometric ratio of 1:1.6:0.4, and a pellet was prepared by molding it.

(Manufacture of all-solid-state secondary batteries)

Example 15

(Anode layer manufacturing)

As a cathode active material, LiNi _0.9 Co _0.05 Mn _0.05 O ₂ (NCM) was coated with Li ₂ ZrO ₃ (LZO) to prepare LZO-NCM cathode active material. Powder was prepared by grinding the pellets of the solid ion conductor compound prepared in Example 1 as a solid electrolyte. Carbon nanofibers (CNF) were prepared as a conductive agent. A positive electrode mixture was prepared by mixing these materials in a weight ratio of LZO-NCM positive electrode active material: solid electrolyte: conductive agent = 60:52:5.

The prepared positive electrode mixture was applied to the current collector and dried to prepare a positive electrode layer. Then, a positive electrode layer with a thickness of 50 μm and a diameter of 11 mm was obtained using a punching machine with a diameter of 11 mm.

(Preparation of solid electrolyte powder)

The solid ion conductor compound prepared in Example 1 was ground using an agate mortar, and the solid electrolyte powder was pressed at a uniaxial pressure of 200 MPa to form a powder with a thickness of about 500 um and a diameter of about 13 mm. A solid electrolyte was prepared as a pellet.

Additionally, a known solid electrolyte (Li ₆ PS ₅ Cl; purchased from Mitsui) was prepared.

(Cathode layer manufacturing)

As a cathode, a metallic lithium foil with a thickness of 20 μm was prepared.

(Manufacture of all-solid-state secondary batteries)

After sequentially stacking the cathode layer, the known solid electrolyte (Li ₆ PS ₅ Cl), the solid electrolyte prepared in Example 1, and the anode layer on the SUS lower electrode, the pressure was applied to 300 MPa using a cold isostatic press (CIP). An all-solid secondary battery was prepared by pressing for 3 minutes under pressure.

Comparative Example 8

(Anode layer manufacturing)

As a cathode active material, LiNi _0.9 Co _0.05 Mn _0.05 O ₂ (NCM) was coated with Li ₂ ZrO ₃ (LZO) to prepare LZO-NCM cathode active material. Powder was prepared by grinding pellets of the solid ion conductor compound prepared in Comparative Example 1 as a solid electrolyte. Carbon nanofibers (CNF) were prepared as a conductive agent. A positive electrode mixture was prepared by mixing these materials in a weight ratio of positive electrode active material: solid electrolyte: conductive agent = 60:52:5.

The prepared positive electrode mixture was applied to the current collector and dried to prepare a positive electrode layer. Then, a positive electrode layer with a thickness of 50 μm and a diameter of 11 mm was obtained using a punching machine with a diameter of 11 mm.

(Preparation of solid electrolyte powder)

The solid ion conductor compound prepared in Comparative Example 1 was ground using an agate mortar, and the solid electrolyte powder was pressed at a uniaxial pressure of 200 MPa to form a powder with a thickness of about 500 um and a diameter of about 13 mm. A solid electrolyte was prepared as a pellet.

Additionally, a known solid electrolyte (Li ₆ PS ₅ Cl; purchased from Mitsui) was prepared.

(Cathode layer manufacturing)

As a cathode, a metallic lithium foil with a thickness of 20 μm was prepared.

(Manufacture of all-solid-state secondary batteries)

After sequentially stacking the cathode layer, the known solid electrolyte (Li ₆ PS ₅ Cl), the solid electrolyte prepared in Comparative Example 1, and the anode layer on the SUS lower electrode, the pressure was applied to 300 MPa using a cold isostatic press (CIP). An all-solid secondary battery was prepared by pressing for 3 minutes under pressure.

Comparative Example 9

(Anode layer manufacturing)

As a cathode active material, LiNi _0.9 Co _0.05 Mn _0.05 O ₂ (NCM) was coated with Li ₂ ZrO ₃ (LZO) to prepare LZO-NCM cathode active material. A known solid electrolyte (Li ₆ PS ₅ Cl; purchased from Mitsui) was prepared as a solid electrolyte. Carbon nanofibers (CNF) were prepared as a conductive agent. A positive electrode mixture was prepared by mixing these materials in a weight ratio of positive electrode active material: solid electrolyte: conductive agent = 60:30:5.

The prepared positive electrode mixture was applied to the current collector and dried to prepare a positive electrode layer. Then, a positive electrode layer with a thickness of 50 μm and a diameter of 11 mm was obtained using a punching machine with a diameter of 11 mm.

(Preparation of solid electrolyte powder)

A known solid electrolyte (Li ₆ PS ₅ Cl; purchased from Mitsui) was prepared.

(Cathode layer manufacturing)

As a cathode, a metallic lithium foil with a thickness of 20 μm was prepared.

(Manufacture of all-solid-state secondary batteries)

A cathode layer, a known solid electrolyte (Li ₆ PS ₅ Cl), and an anode layer were sequentially stacked on the SUS lower electrode, and then pressed for 3 minutes at a pressure of 300 MPa using a cold isostatic press (CIP) to form an all-solid secondary. The battery was prepared.

Evaluation Example 1: XPS Analysis

After preparing the powder by grinding the solid ion conductor compound prepared in Example 1 using an agate mortar, XPS analysis was performed on the powder, and the results are shown in FIG. 9.

Referring to FIG. 9, a peak derived from element “O” was observed at 534 eV in the XPS graph, which proves the presence of PO ₄ anions.

Evaluation Example 2: X-ray diffraction analysis

The solid ion conductor compounds prepared in Examples 1, 2, 4, 5, and 6 were ground using an agate mortar to prepare powder, and then the powder XRD spectrum was measured, and the results are shown in Figure 1. The position of the diffraction angle 2θ = 32.3° peak and the change in full width at half maximum (FWHM) are shown in Figure 2, and the lattice constant of the crystal structure was calculated and shown in Figure 3.

Referring to Figures 1 to 3, it can be seen that Examples 1, 2, 4, 5, and 6 all contain the same crystal structure of the P3-m1 space group, and the lattice changes due to the introduction of the PO ₄ ^3- anion. It was confirmed that the lattice volume increased by about 0.4% as the constant increased.

Evaluation Example 3: Ion conductivity measurement

The solid ion conductor compounds prepared in Examples 1 to 6, Examples 10 to 14, and Comparative Example 1 were pulverized using an agate mortar to prepare powder, and then the powder was subjected to a pressure of 4 ton/cm ² A pellet specimen with a thickness of approximately 1 mm and a diameter of approximately 13 mm was prepared by pressing for 2 minutes. A symmetry cell was prepared by sputtering platinum (Pt) on both sides of the prepared specimen and placing platinum (Pt) electrodes with a thickness of 10 μm and a diameter of 13 mm, respectively. Preparation of the symmetric cell was carried out in a glove box in Ar atmosphere.

The impedance of the pellet was measured using a 2-probe method using an impedance analyzer (Material Mates 7260 impedance analyzer) for a specimen with platinum electrodes placed on both sides. The frequency range was 1 Hz to 1 MHz, and the amplitude voltage was 10 mV. Measured at 25°C in Ar atmosphere. Resistance values were obtained from the arc of the Nyquist plot for the impedance measurement results, and ionic conductivity was calculated considering the area and thickness of the specimen. The measurement results are shown in Table 1 below. Furthermore, the change in ionic conductivity according to the change in p value is shown in Figure 4.

Furtherance 3+m+(l-1)o+2p n 3+m+kn-lo-3p+q p Ion conductivity
(Scm ^-1 ) Example 1 Li _2.1 ZrCl _5.95 (PO ₄ ) _0.05 2.1 One 5.95 0.05 1.0 x 10 ^-3 Example 2 Li _2.02 ZrCl _5.99 (PO ₄ ) _0.01 2.02 One 5.99 0.01 5.6 x 10 ^-4 Example 3 Li _2.04 ZrCl _5.98 (PO ₄ ) _0.02 2.04 One 5.98 0.02 5.7 x 10 ^-4 Example 4 Li _2.08 ZrCl _5.96 (PO ₄ ) _0.04 2.08 One 5.96 0.04 8.2 x 10 ^-4 Example 5 Li _2.12 ZrCl _5.94 (PO ₄ ) _0.06 2.12 One 5.94 0.06 7.7 x 10 ^-4 Example 6 Li _2.2 ZrCl _5.9 (PO ₄ ) _0.1 2.2 One 5.9 0.1 3.2 x 10 ^-4 Example 7 Li _2.15 Zr _0.8 Y _0.2 Cl _5.95 (PO ₄ ) _0.05 2.15 0.8+0.2 5.95 0.05 1.2 x 10 ^-3 Example 8 Li _2.45 Zr _0.5 Y _0.5 Cl _5.95 (PO ₄ ) _0.05 2.45 0.5+0.5 5.95 0.05 1.1 x 10 ^-3 Example 9 Li _2.1 ZrCl _5.95 (PS ₄ ) _0.05 2.1 One 5.95 0.05 4.2 x 10 ^-4 Example 10 Li _2.22 ZrCl _5.89 (PO ₄ ) _0.11 2.22 One 5.89 0.11 4.0 x 10 ^-4 Example 11 Li _2.24 ZrCl _5.88 (PO ₄ ) _0.12 2.24 One 5.88 0.12 3.8 x 10 ^-4 Example 12 Li _2.3 ZrCl _5.85 (PO ₄ ) _0.15 2.3 One 5.85 0.15 3.5 x 10 ^-4 Example 13 Li _2.4 ZrCl _5.8 (PO ₄ ) _0.2 2.4 One 5.8 0.2 3.2 x 10 ^-4 Example 14 Li _2.6 ZrCl _5.7 (PO ₄ ) _0.3 2.4 One 5.8 0.3 2.9 x 10 ^-4 Comparative Example 1 Li ₂ ZrCl ₆ 2 One 6 0 2.8 x 10 ^-4 Comparative Example 2 Li ₃ Y Cl ₆ 3 One 6 0 2.0 x 10 ^-4 Comparative Example 3 Li _2.05 ZrCl _5.95 O _0.05 2.05 One 5.95 0.05 2.2 x 10 ^-5 Comparative Example 4 Li _3.05 YCl _5.95 O _0.05 3.05 One 5.95 0.05 1.8 x 10 ^-5 Comparative Example 5 Li _2.05 ZrCl _5.95 (SO ₄ ) _0.05 2.05 One 5.95 0.05 2.2 x 10 ^-4 Comparative Example 6 Li ₂ ZrCl _5.95 (NO ₃ ) _0.05 2 One 5.95 0.05 2.5 x 10 ^-4 Comparative Example 7 Li _2.8 ZrCl _5.6 (PO ₄ ) _0.4 2.8 One 5.6 0.4 2.5 x 10 ^-4

Referring to Table 1 and Figure 4, the examples in which trivalent anions were introduced were significantly improved compared to the cases where trivalent anions were not substituted (Comparative Example 1) and monovalent or divalent anions were substituted (Comparative Examples 3 to 6). Ionic conductivity was shown. In addition, it was confirmed that trivalent anions had improved ionic conductivity in the range of 0 to 0.3.

Evaluation example 4: Cycle evaluation

The charge/discharge characteristics of the all-solid-state secondary batteries manufactured in Example 10 and Comparative Example 8 were evaluated by the following charge/discharge test.

In the first cycle of the charge/discharge test at room temperature (25°C), the battery was charged at a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V. Next, discharge was performed at a constant current of 0.1C until the battery voltage reached 2.5V. The C rate is the discharge rate of the battery, and is calculated by dividing the total capacity of the battery by the total discharge time. For example, the C rate of a battery with a discharge capacity of 1.6 ampere/hour is 1.6 ampere. The total capacity is determined by the discharge capacity in one cycle. 0.1 C or C/10 means the current required to completely discharge the battery for 10 hours.

The initial efficiencies are shown in Table 2 below. It was confirmed that the battery of Example 10 exhibited superior initial efficiency compared to the fuel efficiency of Comparative Example 8.

initial efficiency Example 1 99.8 Comparative Example 1 92.3

After the initial efficiency evaluation, the battery was charged with a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V. Next, discharge was performed at a constant current of 0.1C until the battery voltage reached 2.5V. This charge/discharge cycle was performed 20 times. The capacity in each cycle was measured and shown in Figure 5.

Referring to Figure 5, the battery of Comparative Example 8 showed a trend of gradually decreasing capacity, but the all-solid-state battery of Example 10 had a coulombic efficiency exceeding 99.8%, confirming that the capacity remained almost constant. .

Evaluation Example 5: Rate characteristics evaluation

The rate characteristics of the all-solid-state secondary batteries manufactured in Example 15 and Comparative Examples 8 and 9 were evaluated by the following test.

At room temperature (25°C), the battery was charged at a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V. Next, discharge was performed at a constant current of 0.1C until the battery voltage reached 2.5V.

Next, the battery was charged at a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V, and then discharged at a constant current of 0.33C until the battery voltage reached 2.5V. .

Next, the battery was charged at a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V, and then discharged at a constant current of 0.5C until the battery voltage reached 2.5V. .

Next, the battery was charged at a constant current of 0.1C and a constant voltage of 4.2V until the battery voltage reached 4.2V, and then discharged at a constant current of 1C until the battery voltage reached 2.5V.

The change in specific capacity of the all-solid-state battery according to the rate change for Example 15 and Comparative Examples 8 and 9 is shown in Figure 6.

Referring to FIG. 6, it was confirmed that the all-solid-state battery of Example 10 showed a capacity retention rate of 43% at a rate of 1 C.

The above has been described with reference to the embodiments shown in the drawings, but these are merely examples, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims.

Claims (20)

Solid ion conductor compounds including compounds represented by the following formula (1):
<Formula 1>
M _{3+m+(l-1)o+2p ( M} ^{' k +} _{) n}
In Formula 1,
M is one or more alkali metals,
M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals,
X is one or more halogen elements,
T is one or more monovalent or divalent anions,
Z is one or more trivalent anions,
2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q). According to paragraph 1,
M is a solid ion conductor compound including Li, Na, K, Rb, Cs, or a combination thereof. According to paragraph 1,
M' is Mg, Zn, Ca, Sr, Ba, Eu, Y, Gd, In, Er, La, Yb, Ce, Ho, Sn, Th, Nb, Mo, W, Sb, Bi, Zr, Hf, Ti , Si, or a combination thereof, a solid ionic conductor compound. According to paragraph 1,
X is a solid ion conductor compound including F, Cl, Br, I, or a combination thereof. According to paragraph 1,
Z is PO ₄ ^3- _, (C ₆ H ₅ O ₇ ) ^3- , PS ₄ ^3- _, [Fe(CN)] ^3- , [Ag(S ₂ O ₃ ) ₂ ] ^3- , N ^3- , P ^3- A solid ionic conductor compound, including a combination thereof. According to paragraph 1,
T is a solid ion conductor compound, including NO ₃ ^- , CH ₃ COO ^- , OH ^- , HCO ₃ ^- , CrO ₄ ^2- , SO ₄ ^2- , CO ₃ ^2- , BH ₄ ^- or a combination thereof. According to paragraph 1,
The formula 1 is a solid ion conductor compound represented by the formula 2:
<Formula 2>
(Li _1-h M _h ) _{3+m+(l-1)o+2p} ⁽ _{M ' k +} ⁾ _n ' _i ) _p
In Formula 2 above,
M is one or more alkali metals excluding Li,
Z' is one or more trivalent anions excluding PO ₄ ^3- ,
M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals,
X is one or more halogen elements,
T is one or more monovalent or divalent anions,
2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q), 0≤h<1, 0≤i<1. According to paragraph 1,
The above formula (1) is a solid ion conductor compound represented by the following formula (3):
<Formula 3>
(Li _1-h M _h ) _{3+m+(l-1)o+2p} (( ^Zr ) _{1 -j} M' _j ^k+ _{) n} PO ₄ ) _1-i Z' _i ) _p
Of the above formula 3,
M is one or more alkali metals excluding Li,
Z' is one or more trivalent anions excluding PO ₄ ^3- ,
M' is one or more metals selected from divalent, trivalent, tetravalent, pentavalent and hexavalent metals excluding Zr,
X is one or more halogen elements,
T is one or more monovalent or divalent anions,
2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, 0<(3+m +kn-lo-3p+q), 0≤h<1, 0≤i<1, 0≤j<1. According to paragraph 1,
The solid ion conductor compound has diffraction angles 2θ=16°±0.5°, 20°±0.5°, 30°±0.5°, 32°±0.5°, 42°±0.5 and 50°±0.50 in the XRD spectrum using CuKα line. A solid ionic conductor compound having a diffraction peak. According to paragraph 1,
Wherein p satisfies 0<p≤0.3, a solid ion conductor compound. According to paragraph 1,
The solid ion conductor compound is a solid ion conductor compound having a crystalline phase, an amorphous phase, or a combination thereof. According to paragraph 1,
A solid ion conductor compound comprising crystals belonging to the P3-m1 space group. According to paragraph 1,
The solid ion conductor compound is a solid ion conductor compound in which the a and c axis lattice constants are increased compared to a compound that does not contain a trivalent anion represented by Z. According to paragraph 1,
The solid ion conductor compounds are Li _2.1 ZrCl _5.95 (PO ₄ ) _0.05 , Li _2.02 ZrCl _5.99 (PO ₄ ) _0.01 , Li _2.04 ZrCl _5.98 (PO ₄ ) _0.02 , Li _2.08 ZrCl _5.96 (PO ₄ ) _0.04 , Li _2.12 ZrCl _{5. 94} (PO ₄ ) _0.06 , Li _2.2 ZrCl _5.9 (PO ₄ ) _0.1 , Li _2.15 Zr _0.8 Y _0.2 Cl _5.95 (PO ₄ ) _0.05 , Li _2.45 Zr _0.5 Y _0.5 Cl _5.95 (PO ₄ ) _0.05 , Li _2.22 ZrCl _5.89 (PO ₄ ) _0.11 , Li _2.24 ZrCl _5.88 (PO ₄ ) _0.12 , Li _2.3 ZrCl _5.85 (PO ₄ ) _0.15, Li _2.4 ZrCl _5.8 (PO ₄ ) _0.2 , Li _2.6 ZrCl _5.7 (PO ₄ ) _0.3 or Li _2.1 ZrCl _5.95 (PS ₄ ) _0.05 , a solid ion conductor compound. A step of preparing a mixture comprising a halide compound containing an M element, a halide compound containing an M' element, and a compound containing a Z element, wherein the M element is one or more alkali metals, and the M' element is divalent, trivalent, tetravalent , one or more metals selected from pentavalent and hexavalent metals, and the Z element is one or more trivalent anions,
A method for producing a solid ion conductor compound, comprising: reacting the mixture in a solid phase to obtain a solid ion conductor compound. According to clause 15,
The step of reacting the mixture in a solid phase to obtain a solid ion conductor compound is,
A method for producing a solid ion conductor compound, comprising performing ball mill mixing of the mixture in a dry and inert atmosphere. According to clause 16,
The ball mill mixing is performed at a first time interval, the ball mill mixing further includes a rest period after the first time interval, and the time interval and the rest period are repeated. A positive electrode layer including a positive electrode active material layer;
A negative electrode layer including a negative electrode active material layer; and
It includes a solid electrolyte layer sandwiched between the anode layer and the cathode layer,
An electrochemical cell comprising the solid ion conductor compound according to any one of claims 1 to 14 in at least one of the anode layer and the solid electrolyte layer. According to clause 18,
The electrochemical cell is an all-solid-state battery, and the solid electrolyte layer includes a sulfide-based solid electrolyte,
The positive electrode active material layer includes a positive electrode active material represented by LiNi _x Co _y Al _z O ₂ or LiNi _x' Co _y' Mn _z' O ₂ , where 0 << 1, x + y + z = 1, 0 <x'< 1, 0 <y'< 1, 0 <z'< 1, x' + y' + z' = 1,
The negative electrode active material layer is an electrochemical cell containing metal lithium. According to clause 18,
An electrochemical cell whose discharge capacity is maintained at more than 93% after 20 cycles compared to the initial discharge capacity when charged and discharged at 0.1C in the range of 2.5V to 4.2V.

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