CN117276641A

CN117276641A - Compound, method for producing same, solid electrolyte, and electrochemical cell

Info

Publication number: CN117276641A
Application number: CN202310752518.XA
Authority: CN
Inventors: 尹加斌; 王琰; 塞缪尔·克洛斯; 马赫迪·阿马彻拉; 权赫兆; 郑度原
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2022-06-22
Filing date: 2023-06-21
Publication date: 2023-12-22

Abstract

Provided are a compound for a solid electrolyte, a method of manufacturing the same, a solid electrolyte including the compound, and an electrochemical cell using the solid electrolyte. The compound is represented by formula 1: li (Li) _4+d H ⁺ _h Sr _2‑x M1 ^a+ _x Zr _1‑y M2 ^b+ _y O _6‑z X ^c‑ _z Wherein, in formula 1, M1 is a cationic dopant in the Sr site, the valence is a+; a is 1, 2 or 3; m2 is a cationic dopant in the Zr site with a valence of b+; b is 2, 3, 4 or 5; x is an anionic dopant in the O site with a valence of c-; c is 1, 2 or 3; h is more than or equal to 0 and less than or equal to 2, x is more than or equal to 0 and less than or equal to 2, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 0.5, x+y+z+h is more than or equal to 0, d= (2-a) x+ (4-b) y- (2-c) z-h, and d is more than or equal to 0.

Description

Compound, method for producing same, solid electrolyte, and electrochemical cell

The present application claims priority and benefit from U.S. provisional application No. 63/354,606, filed on 22 at 6, 2022, and U.S. non-provisional application No. 18/149,635, filed on 3, 2023, 1, which are incorporated herein by reference in their entirety.

Technical Field

The present disclosure relates generally to materials for solid state electrolytes and solid state batteries including the same.

Background

Conventional batteries having a liquid electrolyte may be prone to problems such as leakage of the electrolyte and ignition. In order to improve safety, a solid-state battery (also referred to as an all-solid-state battery) including a solid electrolyte is attracting attention as a next-generation battery. However, there is still a need to solve the problem of separation of the solid electrolyte from the anode in the solid-state battery.

The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art.

Disclosure of Invention

Aspects according to one or more embodiments of the present disclosure relate to a compound for a solid electrolyte having suitable ionic conductivity and stability to lithium (Li) metal and a solid battery including the same.

Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosed embodiments.

According to one or more embodiments of the present disclosure, the compound is represented by formula 1:

1 (1)

Li _4+d H ⁺ _h Sr _2-x M1 ^a+ _x Zr _1-y M2 ^b+ _y O _6-z X ^c- _z ，

Wherein, in the formula 1,

m1 is a cationic dopant in the Sr site with a valence of a+;

a is 1, 2 or 3;

m2 is a cationic dopant in the Zr site with a valence of b+;

b is 2, 3, 4 or 5;

x is an anionic dopant in the O site with a valence of c-;

c is 1, 2 or 3;

0≤h≤2，0≤x≤2，0≤y≤1，0≤z≤0.5，x+y+z+h≥0，

d= (2-a) x+ (4-b) y- (2-c) z-h, and

d≥0。

in some embodiments, d >0.

In some embodiments, the stoichiometric ratio between Li and Zr, represented by (4+d): 1-y, is greater than 4:1.

In some embodiments, the stoichiometric ratio between Li and O, represented by (4+d): 6-z, is greater than 4:6.

In some embodiments, 0< x.ltoreq.2.

In some embodiments, 0< y.ltoreq.1.

In some embodiments, M1 is Na ⁺ 、K ⁺ 、Rb ⁺ 、Cs ⁺ 、Fr ⁺ 、Ca ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Zn ²⁺ 、Be ²⁺ 、Ra ²⁺ 、In ³⁺ 、Sc ³ ⁺ 、Y ³⁺ 、Al ³⁺ 、Ga ³⁺ 、B ³⁺ Or any combination thereof.

In some embodiments, M2 isCa ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Zn ²⁺ 、Be ²⁺ 、Y ³⁺ 、In ³⁺ 、Sc ³⁺ 、B ³⁺ 、Al ³⁺ 、Ga ³⁺ 、Ce ³⁺ 、Pr ³⁺ 、Nd ³⁺ 、Gd ³⁺ 、Ti ⁴⁺ 、Sn ⁴⁺ 、Si ⁴⁺ 、Ge ⁴⁺ 、Pb ⁴⁺ 、Bi ⁵⁺ 、Sb ⁵⁺ 、P ⁵⁺ 、As ⁵⁺ 、Nb ⁵⁺ 、Ta ⁵⁺ Or any combination thereof.

In some embodiments, X is F ^- 、Cl ^- 、Br ^- 、I ^- 、N ^3- Or any combination thereof.

In some embodiments, the compound has an ionic conductivity of about 0.3mS/cm or greater at room temperature.

In some embodiments, a is 1 or 2 and b is 2, 3 or 4.

In one or more embodiments, the solid state electrolyte includes the compound.

In one or more embodiments, an electrochemical cell includes: an anode comprising lithium metal; a cathode facing the anode; and a solid electrolyte between the anode and the cathode, the solid electrolyte including the compound.

In one or more embodiments, the method of making the compound includes: combining a lithium source with two or more selected from the group consisting of a strontium source, a zirconium source, an M1 source, an M2 source, and an X source to form a mixture; and heat treating the mixture to produce the compound.

This summary is provided to introduce a selection of features and concepts of embodiments of the disclosure that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. One or more of the described features may be combined with one or more other described features to provide a viable apparatus.

Drawings

These and other features and enhancements of embodiments of the present disclosure will become more apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings. In the drawings, like reference numerals are used throughout the drawings to designate like features and components. The figures are not necessarily drawn to scale.

Fig. 1 is a schematic diagram of a crystal structure of a compound for a solid state electrolyte according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of an electrochemical cell according to an embodiment of the present disclosure.

Fig. 3 is an Arrhenius plot of Li ion diffusivity of a compound according to example 1 of the present disclosure.

Fig. 4 is an arrhenius plot of Li ion diffusivity of the compound according to comparative example 1.

FIG. 5 illustrates a prediction E of an example compound in accordance with one or more embodiments of the present disclosure _hull 。

Detailed Description

Hereinafter, example embodiments will be described in more detail with reference to the drawings, in which like reference numerals refer to like elements throughout. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the disclosure to those skilled in the art. Thus, processes, elements and techniques not necessary for a person of ordinary skill in the art to fully understand aspects and features of the present disclosure may not be described. Like reference numerals denote like elements throughout the drawings and the specification unless otherwise indicated, and thus, a description thereof may not be repeated.

In the drawings, the relative sizes of elements, layers and regions may be exaggerated and/or simplified for clarity. Spatially relative terms, such as "under … …," "under … …," "lower," "under … …," "over … …," "upper," and the like, may be used herein for ease of explanation to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the example terms "below" and "beneath" can encompass both an orientation of above and below. The device may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Accordingly, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the spirit and scope of the present disclosure.

It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or one or more intervening elements or layers may be present. Furthermore, it will also be understood that when an element or layer is referred to as being "between" two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. A phrase such as "at least one (seed/person)" in … … modifies an entire column of elements when placed after a column of elements, rather than modifying individual elements in the column.

As used herein, the terms "substantially," "about," and the like are used as approximate terms, rather than degree terms, and are intended to explain the inherent variation of measured or calculated values as would be recognized by one of ordinary skill in the art. Furthermore, when describing embodiments of the present disclosure, use of "may" refers to "one or more embodiments of the present disclosure. As used herein, the term "use" and variants thereof may be considered synonymous with the term "utilization", and variants thereof, respectively. Furthermore, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. The term "diameter" as used herein may refer to a diameter of a circular shape or a spherical shape, or an equivalent diameter of a non-circular shape or a non-spherical shape.

The related art solid state battery includes a cathode, an anode, and a Solid State Electrolyte (SSE) between and in direct contact with the cathode and the anode. The anode may include lithium metal. Thus, solid state electrolytes (e.g., while) are desired to have high ionic conductivity and lithium stability.

According to an embodiment of the present disclosure, a compound for a solid electrolyte is represented by formula 1.

1 (1)

Li _4+d H ⁺ _h Sr _2-x M1 ^a+ _x Zr _1-y M2 ^b+ _y O _6-z X ^c- _z

In formula 1, li represents lithium, H represents hydrogen, sr represents strontium, zr represents zirconium, and O represents oxygen; m1 may be a cationic dopant in the strontium (Sr) site with a valence of a+; a may be 1, 2 or 3; m2 may be a cationic dopant in the zirconium (Zr) site with a valence of b+; b may be 2, 3, 4 or 5; x may be an anionic dopant of the oxygen (O) site with a valence of c-; c may be 1, 2 or 3; h is more than or equal to 0 and less than or equal to 2, x is more than or equal to 0 and less than or equal to 2, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 0.5, x+y+z+h is more than or equal to 0, d= (2-a) x+ (4-b) y- (2-c) z-h, and d is more than or equal to 0.

The compound represented by formula 1 includes lithium in a stoichiometric amount of 4 or more, zirconium (Zr) in a stoichiometric amount of 1 or less, and O in a stoichiometric amount of 6 or less. That is, in the compound represented by formula 1, lithium is included in a stoichiometric amount of not less than 4.

In some embodiments, in formula 1, d may be greater than 0, and the stoichiometry of Li may be greater than 4. For example, d may be 0.01 or greater, 0.05 or greater, 0.1 or greater, 0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, or between 0.01 and 1.0. In embodiments, d is 0.1 or greater to 1.0 or less. When d is greater than 0, with the base component Li ₄ Sr ₂ ZrO ₆ The compound represented by formula 1 has an excess of lithium compared to (LSZO base compound).

In some embodiments, the stoichiometric ratio between Li and Zr, represented by (4+d): 1-y, may be greater than 4:1. In some embodiments, the stoichiometric ratio between Li and Zr may be 6:0.5 (i.e., 12:1) or less. In embodiments, the stoichiometric ratio between Li and Zr may be 4.1:1, 4.5:1, 4.9:1, 5.0:1, 5.5:1, 6.0:1, 7.0:1, 8.0:1, 9.0:1, 10.0:1, or 11.0:1.

In some embodiments, the stoichiometric ratio between Li and O, represented by (4+d): 6-z, may be greater than 4:6. In some embodiments, the stoichiometric ratio between Li and O may be 6:6 (i.e., 1:1) or less. In embodiments, the stoichiometric ratio between Li and O may be 4.1:6.0, 4.5:6.0, 5.0:6.0, 6.0:6.0, 4.1:5.8, 4.5:5.8, 5.0:5.8, or 5.5:5.5 (i.e., 1:1).

In formula 1, x represents the stoichiometry of the dopant M1 doped at the Sr site. Hereinafter, the expression "dopant M1 doped at Sr site" means that M1 atom is in the base component Li ₄ Sr ₂ ZrO ₆ The Sr atom is substituted at the position where the Sr atom will be located in the crystal structure of (a). In the compound represented by formula 1, x moles of M1 replace x moles of Sr at the corresponding Sr site.

In some embodiments, sr in formula 1 has a valence of +2, and M1 may be a cationic dopant having a valence of +1, +2, or +3. That is, the valence of Sr is 1 greater than the valence of Sr, the valence of Sr is the same as or less than the valence of Sr, for the M1 atom that replaces a part of Sr atoms. In some embodiments, M1 may be a cationic dopant having a valence of +1 or +2. In some embodiments, 0.ltoreq.x.ltoreq.2, e.g., 0< x.ltoreq.1.5, 0< x.ltoreq.1.2, 0< x.ltoreq.1.0, 0< x.ltoreq.0.5, or 0< x.ltoreq.0.3. In some embodiments, x is 2 and all Sr atoms are substituted with M1. In some embodiments, a is 1 and 0.ltoreq.x.ltoreq.0.5. In some embodiments, a is 2, and 0.ltoreq.x.ltoreq.1, e.g., 0.ltoreq.x.ltoreq.0.9375. In some embodiments, a is 3 and 0.ltoreq.x.ltoreq.0.5. In some embodiments, b is 3 and 0.ltoreq.y.ltoreq.0.5. In some embodiments, b is 4 and 0.ltoreq.y.ltoreq.1. In some embodiments, b is 5, and 0.ltoreq.y.ltoreq.1, e.g., 0.ltoreq.y.ltoreq.0.75.

In some embodiments, M1 may be an alkali metal other than Li and/or may be an alkaline earth metal other than Sr. In some embodiments, M1 may be a monovalent cation, and may be Na ⁺ 、K ⁺ 、Rb ⁺ 、Cs ⁺ 、Fr ⁺ Or any combination thereof. In some embodiments, M1 may be a divalent cation, andcan be Ca ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Zn ²⁺ 、Be ²⁺ 、Ra ² ⁺ Or any combination thereof. In some embodiments, M1 may be a trivalent cation, and may be In ³⁺ 、Sc ³⁺ 、Y ³⁺ 、Al ³ ⁺ 、Ga ³⁺ 、B ³⁺ Or any combination thereof. In some embodiments, M1 may be a monovalent cation, a divalent cation, a trivalent cation, or any combination thereof. In some embodiments, M1 may be Na ⁺ 、K ⁺ 、Ca ²⁺ 、Ba ²⁺ Or any combination thereof.

In formula 1, y represents the stoichiometry of the dopant M2 doped at the Zr site. Hereinafter, the expression "dopant M2 doped at Zr site" means that the M2 atom is in the base component Li ₄ Sr ₂ ZrO ₆ The Zr atom is substituted at the position where the Zr atom will be located in the crystal structure. In the compound represented by formula 1, y moles of M2 replace y moles of Zr at the corresponding Zr sites.

In some embodiments, zr in formula 1 has a valence of +4, and M2 may be a cationic dopant having a valence of +2, +3, +4, or +5. That is, the valence of the M2 atom for substituting a part of the Zr atoms is 1 larger than that of Zr, the same as that of Zr or smaller than that of Zr. In some embodiments, M2 may be a cationic dopant having a valence of +2, +3, or +4. In some embodiments, 0.ltoreq.y.ltoreq.1, e.g., 0.ltoreq.y.ltoreq.0.8, 0.ltoreq.y.ltoreq.0.6, 0.ltoreq.y.ltoreq.0.5, 0.ltoreq.y.ltoreq.0.3, or 0.ltoreq.y.ltoreq.0.1. In an embodiment, y is 0 and the Zr sites are not doped with other materials. In an embodiment, y is 1 and all Zr atoms are substituted by M2.

In some embodiments, M2 may be a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or any combination thereof. In some embodiments, M2 may be a divalent cation, and may be Ca ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Be ²⁺ 、Ra ²⁺ Or any combination thereof. In some embodiments, M2 may be a trivalent cation andmay be Y ³⁺ 、In ³⁺ 、Sc ³⁺ 、B ³ ⁺ 、Al ³⁺ 、Ga ³⁺ 、Ce ³⁺ 、Pr ³⁺ 、Nd ³⁺ 、Gd ³⁺ Or any combination thereof. In some embodiments, M2 may be a tetravalent cation, and may be Ti ⁴⁺ 、Sn ⁴⁺ 、Si ⁴⁺ 、Ge ⁴⁺ 、Pb ⁴⁺ Or a combination thereof. In some embodiments, M2 may be a pentavalent cation and may be Bi ⁵⁺ 、Sb ⁵⁺ 、P ⁵⁺ 、As ⁵⁺ 、Nb ⁵⁺ 、Ta ⁵⁺ Or a combination thereof. In some embodiments, M2 may be Mg ²⁺ 、Zn ²⁺ 、Y ³⁺ 、In ³⁺ 、Sc ³⁺ 、Ti ⁴⁺ 、Sn ⁴⁺ 、Si ⁴⁺ 、Ge ⁴⁺ Or any combination thereof.

In formula 1, z represents the stoichiometry of the anionic dopant X doped at the O site. Hereinafter, the expression "dopant X doped at the O site" means that the X atom is in the base component Li ₄ Sr ₂ ZrO ₆ The O atom is substituted at the position where the O atom will be located in the crystal structure of (a). In the compound represented by formula 1, z moles of X replace z moles of O at the corresponding O site. In some embodiments, X in formula 1 has a valence of-1, -2, or-3. In some embodiments, 0.ltoreq.z.ltoreq.0.5, e.g., 0.ltoreq.z.ltoreq.0.4, 0.ltoreq.z.ltoreq.0.3, 0.ltoreq.z.ltoreq.0.2, or 0.ltoreq.z.ltoreq.0.1. In an embodiment, z is 0 and the O sites are not doped with other materials.

In some embodiments, X may be a monovalent anion (such as F ^- 、Cl ^- 、Br ^- 、I ^- ) Trivalent anions (such as N ^3- ) Or any combination thereof.

In formula 1, H represents the stoichiometry of hydrogen (H) doped at the Li site. Hereinafter, the expression "H doped at Li site" means that H atoms are in the base component Li ₄ Sr ₂ ZrO ₆ The Li atom is substituted at the position where the Li atom will be located in the crystal structure of (a). In the compound represented by formula 1, H moles of H replace H moles of Li at the corresponding Li sites.During the manufacturing process of the compound for the solid electrolyte, H may be introduced into the Li site after the acid treatment.

In some embodiments, 0.ltoreq.h.ltoreq.2, e.g., 0.ltoreq.h.ltoreq.1.0, 0.ltoreq.h.ltoreq.0.5, 0.ltoreq.h.ltoreq.0.2, or 0.ltoreq.z.ltoreq.0.1. In an embodiment, H is 0 and the Li sites are not doped with H.

In some embodiments, at least one of the Sr site, zr site, and O site may be doped with a respective one of M1, M2, and X. In an embodiment, the Sr site is doped with M1. In an embodiment, zr sites are doped with M2. In an embodiment, the O site is doped with X. In an embodiment, both Sr sites and Zr sites are doped with the corresponding dopants at the same time. In an embodiment, both the Sr site and the O site are doped with the respective dopants at the same time. In an embodiment, both Zr sites and O sites are doped with the corresponding dopants at the same time. In an embodiment, the Sr site, zr site and O site are all doped simultaneously with the corresponding dopants.

In the compound represented by formula 1, li is included in a stoichiometric amount of 4 or more, while Zr is in a stoichiometric amount of 1 or less, and O is in a stoichiometric amount of 6 or less. Further, in one or more embodiments, in the compound represented by formula 1, the Sr site is doped with a dopant M1 having a valence not greater than that of Sr. In some embodiments, the compound represented by formula 1 may further include a dopant M2 having a valence not greater than Zr doped at the Zr site. The compound represented by formula 1 may thus have suitable ionic conductivity to ensure satisfactory performance of the solid-state battery. In some embodiments, the compound represented by formula 1 may have an ionic conductivity of about 0.3mS/cm or greater at 25 ℃ (e.g., room temperature, RT). In some embodiments, the compound represented by formula 1 may have an ionic conductivity of about 0.4mS/cm or greater at 25 ℃.

In solid state batteries, solid state electrolytes with high ionic conductivity and a wide electrochemical stability window are desired. Oxide-based materials may have suitable air stability and electrochemical stability without toxicity problems, but related art oxide-based materials typically have about 0.0 at about 25 deg.cLow ionic conductivity of 1mS/cm or less, mainly due to low bulk conductivity or high grain boundary resistance. Of the oxide-based materials of the related art, only garnet Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO) shows conductivity exceeding 1mS/cm, but it requires a fine treatment because an insulating lithium carbonate coating layer is formed even if it is stored in a glove box. In addition, with Li ₇ La ₃ Zr ₂ O ₁₂ In contrast, the compound represented by formula 1 uses relatively lighter element Sr than lanthanum (La). A comparison between La and Sr is shown in table 1. As shown in table 1, la is also more expensive than Sr because it is less global. Therefore, the compound represented by formula 1 is also cheaper than the lithium garnet of the related art.

TABLE 1

Element(s)	Name of the name	Density (Kg/L)	Crust abundance (mg/kg)
				La	Lanthanum, lanthanum alloy	6.145	39(1.08×10 ¹⁸ kg)
Sr	Strontium (strontium)	2.64	370(1.025×10 ¹⁹ kg)

The compound represented by formula 1 employs Li as shown in FIG. 1 ₄ Sr ₂ ZrO ₆ Structure is as follows. Referring to FIG. 1, in Li ₄ Sr ₂ ZrO ₆ In structure, lithium 101 and metal 102 (e.g., sr and Zr) are coordinated by oxygen 103. Doped Li represented by formula 1 ₄ Sr ₂ ZrO ₆ The material adopts a similar structure. The dopant M1 in formula 1 is understood to be present at the Sr site in the structure, and the dopant M2 is understood to be present at the Zr site in the structure. It has surprisingly been found that the disclosed compounds provide an improved combination of stability to lithium metal and ionic conductivity. While not wishing to be bound by any particular theory, it is understood that when the disclosed compounds have an excess of lithium (e.g., in Li ₄ Sr ₂ ZrO ₆ When the stoichiometric amount of lithium exceeds 4), excess lithium is accommodated in the interstitial crystallization sites and the charge passes Sr as described by d= (2-a) x+ (4-b) y- (2-c) z-h ²⁺ Or Zr (Zr) ⁴⁺ Valence of (Sr) ²⁺ Site, zr ⁴⁺ Sites and/or O ^2- Amount of dopant at site, and/or Sr ²⁺ Site, zr ⁴⁺ Sites and/or O ^2- Combinations of different valences at the sites to compensate, resulting in improved lithium conductivity. In addition, by substituting Sr with cations having a valence of 1+, 2+, or 3+ ²⁺ Substitution of Zr with cations having valence 2+, 3+, 4+ or 5+ ⁴⁺ And/or with anions having a valence of-3 or less (e.g., nitrogen anions (N) ^3- ) Substituted for oxygen, may provide further improvements. While not wishing to be bound by any particular theory, it is understood that such substitution provides an increased amount of excess lithium, resulting in improved lithium conductivity. It is understood that increased lithium content results in unexpectedly reduced activation energy, which is why improved lithium conductivity is observed.

Among materials studied for solid electrolytes, sulfide-based materials have been found to have high ionic conductivity [ ]>10 mS/cm). Examples of sulfide-based materials for solid state electrolytes may include Li ₂ S-P ₂ S ₅ 、Li ₂ S-P ₂ S ₅ LiX (wherein X is a halogen element), li ₂ S-P ₂ S ₅ -Li ₂ O、Li ₂ S-P 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 S-B ₂ S ₃ 、Li ₂ -P ₂ S ₅ -Z _m S _n (wherein m and n are each positive numbers, and Z represents any one of Ge, zn and Ga), li ₂ S-GeS ₂ 、Li ₂ S-SiS ₂ -Li ₃ PO ₄ 、Li ₂ S-SiS ₂ -Li _p MO _q (wherein p and q are each positive numbers, M represents at least one of P, si, ge, B, al, ga and In), li _7-x PS _6-x Cl _x (wherein, x is more than or equal to 0 and less than or equal to 2), li _7-x PS _6-x Br _x (wherein 0.ltoreq.x.ltoreq.2) or Li _7-x PS _6-x I _x Wherein x is more than or equal to 0 and less than or equal to 2). However, sulfide-based materials are unsafe to use and have unsatisfactory electrochemical stability. For example, sulfide-based materials may generate toxic gases (e.g., H ₂ S), toxic gases (e.g., H ₂ S) can then be oxidized in air and elemental sulfur formed. Furthermore, sulfide-based materials, when in contact with Li metal, may react with Li to corrode the Li metal anode.

The compound represented by formula 1 has better Li stability and is safer to use than sulfide-based materials. That is, the compound represented by formula 1 provides suitable ionic conductivity and electrochemical stability (e.g., is stable when in contact with Li metal). Non-limiting examples of the compound represented by formula 1 may include: 1) When (4+d)/(1-y) is not less than 4:1: li (Li) ₄ H _0.25 Sr ₂ Zr _0.875 Ba _0.125 O ₆ 、Li ₄ Sr _1.25 K ⁺ _0.75 Zr _0.25 Ta ⁵⁺ _0.75 O ₆ 、Li ₄ Sr _1.75 Ca ²⁺ _0.25 Zr _0.75 Sn ⁴⁺ _0.25 O ₆ 、Li ₄ Sr _1.0 Y ³⁺ _1.0 Zr _0.5 Ba ²⁺ _0.5 O ₆ 、Li _4.25 Sr _2.0 Zr _0.875 M2 ²⁺ _0.125 O ₆ 、Li _4.1875 Sr _2.0 Zr _0.75 M2 ²⁺ _0.25 O _5.9375 X ^3- _0.0625 、Li _5.25 H _0.5 Sr _1.75 M1 ⁺ _0.25 Zr _0.25 M2 ²⁺ _0.75 O ₆ 、Li _5.75 Sr _1.5 M1 ⁺ _0.5 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.9375 H _0.75 Sr _1.0 M1 ⁺ _1.0 Zr _0.5 M2 ²⁺ _0.5 O _5.9375 X ^3- _0.0625 、Li _6.5 Sr _1.5 M1 ⁺ _0.5 M2 ²⁺ _1.0 O ₆ 、Li _5.375 H _0.25 M1 ⁺ _2.0 Zr _0.75 M2 ³⁺ _0.25 O _5.875 X ^3- _0.125 、Li _5.5 Sr _0.5 M1 ⁺ _1.5 Zr _1.0 O ₆ 、Li _5.25 H _0.25 Sr _0.5 M1 ⁺ _1.5 Zr _1.0 O ₆ And Li (lithium) _4.75 Sr _1.0 M1 ⁺ _1.0 Zr _0.75 M2 ⁵⁺ _0.25 O ₆ The method comprises the steps of carrying out a first treatment on the surface of the 2) When (4+d)/(6-z)>4/6: li (Li) _4.25 Sr _2.0 Zr _0.875 M2 ²⁺ _0.125 O ₆ 、Li _4.5 Sr _2.0 Zr _0.75 M2 ²⁺ _0.25 O ₆ 、Li _4.25 H _0.25 Sr _2.0 Zr _0.75 M2 ²⁺ _0.25 O ₆ 、Li _4.1875 Sr _2.0 Zr _0.75 M2 ²⁺ _0.25 O _5.9375 X ^3- _0.0625 、Li _4.75 Sr _2.0 Zr _0.625 M2 ²⁺ _0.375 O ₆ 、Li _4.5 H _0.25 Sr _2.0 Zr _0.625 M2 ²⁺ _0.375 O ₆ 、Li _4.25 H _0.5 Sr _2.0 Zr _0.625 M2 ²⁺ _0.375 O ₆ 、Li _5.25 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _5.0 H _0.25 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.75 H _0.5 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.5 H _0.75 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.25 H _1.0 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _5.0 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.75 H _0.25 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ 、Li _4.5 H _0.5 Sr _2.0 Zr _0.375 M2 ² ⁺ _0.625 O ₆ And Li (lithium) _4.25 H _0.75 Sr _2.0 Zr _0.375 M2 ²⁺ _0.625 O ₆ The method comprises the steps of carrying out a first treatment on the surface of the Etc., wherein M1 ⁺ Monovalent cationic dopant being the Sr site, M2 ²⁺ Divalent cation dopant of Zr site, M2 ³⁺ Trivalent cationic dopant being Zr site, M2 ⁵⁺ Is a pentavalent cationic dopant of Zr site, and X ^3- Is a trivalent cationic dopant of the O site, examples of each of which are the same as described above.

Fig. 2 is a schematic diagram of an electrochemical cell (such as a solid state battery) according to an embodiment of the present disclosure. Referring to fig. 2, the electrochemical cell includes a cathode (also referred to as a positive electrode) 12, an anode (also referred to as a negative electrode) 18, and a Solid State Electrolyte (SSE) 14 between the cathode 12 and the anode 18.

The cathode 12 may include a positive electrode active material layer 12-1 on a current collector 12-2, and the positive electrode active material layer 12-1 includes a positive electrode active material. The current collector may comprise a suitable material, such as aluminum. Cathode 12 may be prepared by any suitable method, such as screen printing, slurry casting, or powder compression of the positive electrode active material onto a current collector. However, the method of preparing the cathode is not limited thereto, and any suitable method may be used.

The positive electrode active material may include any suitable material, such as a lithium transition metal oxide, a transition metal sulfide, or a combination thereof. Exemplary positive electrode active materials may include one or more compounds represented by the following formula: li (Li) _a A _1- _b R _b D ₂ (0.90.ltoreq.a.ltoreq.1.8, and 0.ltoreq.b.ltoreq.0.5); li (Li) _a E _1-b R _b O _2-c D _c (0.90.ltoreq.a.ltoreq. 1.8,0.ltoreq.b.ltoreq.0.5, and 0.ltoreq.c.ltoreq.0.05); liE _2-b R _b O _4-c D _c (0≤b≤0.5,0≤c≤0.05)；Li _a Ni _1-b-c Co _b R _c D _α (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α≤2)；Li _a Ni _1-b-c Co _b R _c O _2-α Z _α (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α<2)；Li _a Ni _1-b-c Co _b R _c O _2-α Z ₂ (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α<2)；Li _a Ni _1-b-c Mn _b R _c D _α (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α≤2)；Li _a Ni _1-b- _c Mn _b R _c O _2-α Z _α (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α<2)；Li _a Ni _1-b-c Mn _b R _c O _2-α Z ₂ (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.5, c is more than or equal to 0 and less than or equal to 0.05, and 0<α<2)；Li _a Ni _b E _c G _d O ₂ (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.9, c is more than or equal to 0 and less than or equal to 0.5, and d is more than or equal to 0.001 and less than or equal to 0.1); li (Li) _a Ni _b Co _c Mn _d G _e O ₂ (a is more than or equal to 0.90 and less than or equal to 1.8,0, b is more than or equal to 0.9, c is more than or equal to 0 and less than or equal to 0.5, d is more than or equal to 0 and less than or equal to 0.5, and e is more than or equal to 0.001 and less than or equal to 0.1); li (Li) _a NiG _b O ₂ (0.90.ltoreq.a.ltoreq.1.8, and 0.001.ltoreq.b.ltoreq.0.1); li (Li) _a CoG _b O ₂ (0.90.ltoreq.a.ltoreq.1.8, and 0.001.ltoreq.b.ltoreq.0.1); li (Li) _a MnG _b O ₂ (0.90.ltoreq.a.ltoreq.1.8, and 0.001.ltoreq.b.ltoreq.0.1); li (Li) _a Mn ₂ G _b O ₄ (0.90.ltoreq.a.ltoreq.1.8, and 0.001.ltoreq.b.ltoreq.0.1); QO (quality of service) ₂ ；QS ₂ ；LiQS ₂ ；V ₂ O ₅ ；LiV ₂ O ₅ ；LiTO ₂ ；LiNiVO ₄ ；Li _(3-f) J ₂ (PO ₄ ) ₃ (0≤f≤2)；Li _(3-f) Fe ₂ (PO ₄ ) ₃ (f is more than or equal to 0 and less than or equal to 2); liFePO ₄ 。

In the above formulas, a includes, but is not limited to, ni, co, mn, or combinations thereof; r includes, but is not limited to Al, ni, co, mn, cr, fe, mg, sr, V, rare earth elements, or combinations thereof; d includes, but is not limited to O, F, S, P or combinations thereof; e includes, but is not limited to Co, mn, or combinations thereof; z includes, but is not limited to F, S, P or combinations thereof; g includes, but is not limited to Al, cr, mn, fe, mg, la, ce, sr, V or combinations thereof; q includes, but is not limited to, ti, mo, mn, or combinations thereof; t includes, but is not limited to Cr, V, fe, sc, Y or combinations thereof; and J includes, but is not limited to V, cr, mn, co, ni, cu or combinations thereof.

The positive electrode active material layer may include a positive electrode active material, and may further include a conductive agent and/or a binder. Any suitable conductive agent and binder may be used. The binder may promote adhesion between components of the electrode, such as the positive electrode active material and the conductive agent, and adhesion of the electrode to the current collector. Examples of binders may include polyacrylic acid (PAA), polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene diene copolymer (EPDC), sulfonated EPDC, styrene-butadiene rubber, fluorinated rubber, copolymers thereof, or combinations thereof. The amount of the binder may be in the range of about 1 to about 10 parts by weight, for example, in the range of about 2 to about 7 parts by weight, based on the total weight of the positive electrode active material. When the amount of the binder is within the above range (for example, within a range of about 1 part by weight to about 10 parts by weight), the adhesion of the electrode to the current collector may be suitably strong.

The conductive agent may include, for example, carbon black, carbon fibers, graphite, carbon nanotubes, graphene, or combinations thereof. The carbon black may be, for example, acetylene black, ketjen black, super P carbon (Super P carbon), channel black, furnace black (lamp black), lamp black (lamp black), thermal black (thermal black), or a combination thereof. The graphite may be natural graphite or artificial graphite. Combinations comprising at least one of the foregoing conductive agents may be used. The positive electrode may additionally include an additional conductive agent in addition to the carbonaceous conductive agent described above. The additional conductive agent may be: conductive fibers (such as metal fibers); metal powder (such as aluminum powder or nickel powder); conductive whiskers (such as zinc oxide or potassium titanate); or a conductive polymer (such as a polyphenylene derivative).

The positive electrode may be prepared from a positive electrode active material composition including a positive electrode active material and optionally a conductive agent and a binder. In an embodiment, the positive electrode active material composition is disposed on a current collector (such as an aluminum current collector) to form a positive electrode. Screen printing, slurry casting or powder compaction may be used, the details of which may be determined by one skilled in the art without undue experimentation and which will not be further elaborated herein for the sake of clarity.

Anode 18 may include a negative active material layer 18-1 and a current collector 18-2. The anode active material may include a metal, a transition metal nitride, or a combination thereof. Examples of suitable materials for forming anode 18 may include lithium (Li), gold (Au), copper (Cu), nickel (Ni), aluminum (Al), silver (Ag), titanium nitride (TiN), gallium nitride (GaN), molybdenum nitride (MoN), or combinations thereof. In some embodiments, the negative active material may include lithium metal, a lithium alloy, or a combination thereof. The current collector may be any suitable material, such as a copper current collector.

The solid electrolyte (SSE) 14 may be an ion conductor and an electronic insulator, and may include a compound for a solid electrolyte represented by formula 1. The solid electrolyte may include a layer formed of the compound represented by formula 1, and the layer may be in direct contact with the anode and/or the cathode of the solid battery.

In some embodiments, the solid electrolyte may be formed using the compound represented by formula 1 as a main component, for example, may be formed using more than 50%, 70%, or 90% or more of the compound represented by formula 1 as a main component, based on the total weight of the solid electrolyte. In an embodiment, the solid electrolyte may be formed using only the compound represented by formula 1. In an embodiment, the solid state electrolyte may be in direct contact with both the anode and the cathode of the solid state battery.

The compound of formula 1 may be synthesized by combining a lithium-containing compound, a strontium-containing compound, a zirconium-containing compound, and at least one compound containing M1, M2, and X in appropriate stoichiometric amounts to form a mixture, and heat-treating the mixture to prepare the compound of formula 1. In an embodiment, the method may further comprise acid treatment of the heat treated product.

Exemplary compounds comprising lithium, strontium, zirconium, M1 and M2 may include oxides, nitrides, oxynitrides, nitrates, hydroxides and/or carbonates of each of these elements. For example, lithium carbonate, lithium nitrate, strontium oxide, zirconium oxide, magnesium carbonate, magnesium oxide, aluminum carbonate, or the like can be used.

The compound comprising X may be a lithium salt comprising X. For example, liF may be used when X is F, or LiCl may be used when X is Cl.

The mixture may be heat treated in air at a temperature of 700 to 1000 ℃ in a suitable container such as a crucible for 2 to 10 hours. The resultant material may be ground for 30 minutes to a fine powder by a ball mill. If desired, a wet process (such as wet milling in methanol) may be used. The dried powder may again be treated at a suitable temperature of 700 ℃ to 1000 ℃ for 2 hours to 24 hours to provide the desired phase. If desired, the product may be milled again, for example by ball milling, to provide the appropriate form. The particle size of the ball-milled powder may be less than 1 μm or less than 5 μm. If desired, the ball-milled powder may be mixed with a suitable amount of a 3 weight percent (wt%) polyvinyl alcohol (PVA) solution, or the ball-milled powder may be pressed into PVA-free pellets (billets) at a pressure of 1 ton to 10 tons. The pellets may be sintered in air at a temperature in the range of 1000 ℃ to 1300 ℃ for 2 hours to 4 hours.

The compound represented by formula 1 may be in the form of particles. The particles may have, for example, a spherical form and/or an ellipsoidal form, etc. The particle diameter is not particularly limited, and the average particle diameter may be, for example, 0.01 μm to 50 μm, 0.1 μm to 25 μm, or 0.2 μm to 10 μm. The average particle diameter refers to the number average diameter (D50) of the particle size distribution of particles obtained by scattering or the like. The particles may be processed, for example, by mechanical milling, to provide a suitable particle size.

In some embodiments, a film including the compound of formula 1 may be provided on the peeling layer, the film being provided on at least one of the anode and the cathode; removing the peeling layer; and then a negative electrode was disposed on the positive electrode, thereby manufacturing a battery.

The disclosure is further illustrated by the following non-limiting examples. In an example, activation energy and ion conductivity are determined by de novo computational molecular dynamics (AIMD) based on Density Functional Theory (DFT). The first sexual principle calculation is performed using density functional theory as implemented in the plane wave basis set vienna from head calculation modeling package (Vienna ab initio simulation package, VASP). The projective prefix-plus-wave potential with a kinetic energy cutoff of 520eV is applied in all structural optimizations and total energy calculations (Projector augmented wave potentials), and the exchange-correlation function is described in Perdew-Burke-ernzehof generalized gradient approximation (Perdew-Burke-Ernzerhof generalized gradient approximation, GGA-PBE) (Exchange and correlation functionals). A k-point density of at least 500 per atom in the unit cell was used in all calculations.

The simulation was performed on a regular basis with a time step of 2 femtoseconds (fs), a temperature initialization of 100 kelvin (K) and an increase to the appropriate temperature (600K, 720K, 900K, 1200K and 1500K), the simulation lasting 200 picoseconds (ps) for statistical analysis. Only gamma point sampling of k-space and a lower but sufficient plane wave energy cutoff than the structural optimization calculation are used.

Example 1

Calculation of Li _4.5 Sr _1.5 K _0.5 ZrO ₆ The results of the arrhenius diagram of Li ion diffusivity of (2) are shown in fig. 3. As shown in fig. 3, this example compound according to an embodiment of the present disclosure has an activation energy E of 0.23eV _a And a Li ion conductivity of about 0.415mS/cm at 300K.

Comparative example 1

Similarly to example 1, li is calculated _3.957 Sr _1.957 La _0.043 ZrO ₆ The results of the arrhenius diagram of Li ion diffusivity of (c) are shown in fig. 4. As shown in FIG. 4, the comparative material has an E of 0.84eV _a And less than 1X 10 at 300K ^-6 Li ion conductivity of mS/cm.

Comparing example 1 with comparative example 1, by including excess lithium (relative to the LSZO base compound) in the compound according to embodiments of the disclosure and by adding a dopant (e.g., sr ²⁺ K in site ⁺ Dopants), compounds according to embodiments of the present disclosure are capable of achieving fast Li ⁺ Diffusion, and thus exhibits much greater ionic conductivity than comparative example 1.

Without being bound by any particular theory, it is believed that in using Li _3.75 Sr _1.75 La _0.25 ZrO ₆ In comparative example 1 of (1), when La ³⁺ At Sr ²⁺ When used as dopants in the sites, li defects can be generated in the material, which results in higher Li ⁺ Activation energy and thus very low Li production ⁺ Ion conductivity.

Thermodynamic stability of the Compounds

Thermodynamic stability of compounds according to embodiments of the present disclosure was calculated using high flux Density Functional Theory (DFT) calculations. Table 2 lists example dopants considered for doping Sr sites and Zr sites. For example, a blend selected from group A, B and group C (or set)The impurity agent M1 is used for doping Sr ²⁺ Sites, and dopant M2 selected from group C, D and E (or set) for doping Zr ⁴⁺ Sites to generate a complex of Li _4+d H ⁺ _h Sr _2-x M1 ^a+ _x Zr _1-y M2 ^b+ _y O _6-z X ^c- _z Various compounds are represented. In these example compounds, the Li stoichiometry is fixed to 4,O stoichiometry is fixed to 6, the sr stoichiometry is 2 or less, and the Zr stoichiometry is 1 or less.

By calculating the energy above the linear combination of stable phases in the first principle phase diagram (also called energy above hull) (E _hull ) To estimate the phase stability of the predicted material. For the phase diagram construction, the energy of all compounds except those of direct interest in this work was obtained from Materials Project using the material application programming interface (Materials Application Programming Interface, API). To determine the threshold (beyond which Li _4+d H ⁺ _h Sr _2-x M1 ^a+ _x Zr _1-y M2 ^b+ _y O _6-z X ^c- _z Is considered to be unstable), taking into account the ideal configuration entropy (S) _ideal ＝-K _b ∑ _i p _i ln p _i ) Wherein K is _b Is Boltzmann constant, p _i Is the probability of each state (occupied or unoccupied) and the sum is the sum of all states of each site. Note that co-doping Zr ⁴⁺ And Sr ²⁺ (e.g. simultaneous doping of Zr) ⁴⁺ And Sr ²⁺ ) Resulting in increased configuration entropy and thus facilitating having significantly larger E _hull Synthesis of the phases of values. Here, a threshold value E of 100meV/atom is employed _hull 。

Threshold E satisfying 100meV/atom _hull Examples of the compounds of (C) include D-Li-O-Sr, C-E-Li-O-Sr, D-Li-O-Sr-Zr, B-D-Li-O-Sr, A-B-D-E-Li-O, A-B-E-Li-O-Zr, A-E-Li-O-Sr-Zr, A-B-E-Li-O, A-B-E-Li-O-Sr, B-D-Li-O-Sr-Zr, B-Li-O-Sr-Zr, C-E-Li-O-Sr-Zr, B-C-D-E-Li-O, B-C-E-Li-O-Sr, A-D-E-Li-O-Sr, C-D-E-Li-O-Sr, A-B-C-E-Li-O, A-CE-Li-O-Sr, B-C-E-Li-O, A-E-Li-O-Sr, B-D-Li-O-Zr, B-D-Li-O, B-C-E-Li-O-Zr, B-Li-O-Zr and A-C-Li-O-Zr. Here, A, B, C, D and E are selected from the substances shown in Table 2 and give rise to the desired E _hull The stoichiometric range of each of these compounds of (a) is also listed in table 2. For example, the compound represented by D-Li-O-Sr may be a Sn-Li-O-Sr compound and includes Sn in a stoichiometric range of 0 to 1.

TABLE 2

FIG. 5 shows predictions E for various exemplary compounds _hull . As can be seen from fig. 5, all compounds represented by the above formula have an average E of less than 100meV/atom _hull 。

While the present disclosure has been described in detail with particular reference to example embodiments thereof, the example embodiments described herein are not intended to be exhaustive or to limit the scope of the disclosure to the precise forms disclosed. It will be appreciated by those skilled in the art and technology to which this disclosure pertains that alterations and changes in the described structures and methods of assembly and operation may be practiced without meaningfully departing from the principles, spirit and scope of this disclosure, as set forth in the appended claims and their equivalents.

Claims

1. A compound represented by formula 1:

1 (1)

Li _4+d H ⁺ _h Sr _2-x M1 ^a+ _x Zr _1-y M2 ^b+ _y O _6-z X ^c- _z ，

Wherein, in the formula 1,

m1 is a cationic dopant in the Sr site with a valence of a+;

a is 1, 2 or 3;

m2 is a cationic dopant in the Zr site with a valence of b+;

b is 2, 3, 4 or 5;

x is an anionic dopant in the O site with a valence of c-;

c is 1, 2 or 3;

0≤h≤2，0≤x≤2，0≤y≤1，0≤z≤0.5，x+y+z+h≥0，

d= (2-a) x+ (4-b) y- (2-c) z-h, and

d≥0。

2. the compound of claim 1, wherein d >0.

3. The compound of claim 1, wherein the stoichiometric ratio between Li and Zr represented by (4+d): 1-y is greater than 4:1.

4. The compound of claim 1, wherein the stoichiometric ratio between Li and O represented by (4+d): 6-z is greater than 4:6.

5. The compound of claim 1, wherein 0< x.ltoreq.2.

6. The compound of claim 1, wherein 0< y.ltoreq.1.

7. The compound of claim 1, wherein M1 is Na ⁺ 、K ⁺ 、Rb ⁺ 、Cs ⁺ 、Fr ⁺ 、Ca ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Zn ²⁺ 、Be ²⁺ 、Ra ²⁺ 、In ³⁺ 、Sc ³⁺ 、Y ³⁺ 、Al ³⁺ 、Ga ³⁺ 、B ³⁺ Or any combination thereof.

8. The compound of claim 1, wherein M2 is Ca ²⁺ 、Ba ²⁺ 、Mg ²⁺ 、Zn ²⁺ 、Be ²⁺ 、Y ³⁺ 、In ³⁺ 、Sc ³⁺ 、B ³ ⁺ 、Al ³⁺ 、Ga ³⁺ 、Ce ³⁺ 、Pr ³⁺ 、Nd ³⁺ 、Gd ³⁺ 、Ti ⁴⁺ 、Sn ⁴⁺ 、Si ⁴⁺ 、Ge ⁴⁺ 、Pb ⁴⁺ 、Bi ⁵⁺ 、Sb ⁵⁺ 、P ⁵⁺ 、As ⁵⁺ 、Nb ⁵⁺ 、Ta ⁵⁺ Or any combination thereof.

9. The compound of claim 1, wherein X is F ^- 、Cl ^- 、Br ^- 、I ^- 、N ^3- Or any combination thereof.

10. The compound of claim 1, wherein the compound has an ionic conductivity of 0.3mS/cm or greater at room temperature.

11. The compound of claim 1, wherein a is 1 or 2 and b is 2, 3 or 4.

12. A solid state electrolyte comprising the compound of claim 1.

13. The solid-state electrolyte of claim 12, wherein the stoichiometric ratio between Li and Zr represented by (4+d): 1-y is greater than 4:1.

14. The solid-state electrolyte of claim 12, wherein the stoichiometric ratio between Li and O, represented by (4+d): 6-z, is greater than 4:6.

15. An electrochemical cell, the electrochemical cell comprising:

an anode comprising lithium metal;

a cathode facing the anode; and

a solid-state electrolyte comprising the compound of claim 1 between an anode and a cathode.

16. The electrochemical cell of claim 15, wherein a stoichiometric ratio between Li and Zr represented by (4+d): 1-y is greater than 4:1.

17. The electrochemical cell of claim 15, wherein a stoichiometric ratio between Li and O, represented by (4+d): 6-z, is greater than 4:6.

18. A method of preparing the compound of claim 1, the method comprising:

combining a lithium source with two or more selected from the group consisting of a strontium source, a zirconium source, an M1 source, an M2 source, and an X source to form a mixture; and

the mixture is heat treated to produce the compound.

19. The method of claim 18 wherein the stoichiometric ratio between Li and Zr represented by (4+d): 1-y is greater than 4:1.

20. The method of claim 18 wherein the stoichiometric ratio between Li and O represented by (4+d): 6-z is greater than 4:6.