Electrolyte Materials and Methods for Forming the Same

Abstract

The present invention discloses a solid electrolyte material, which may include a halide-based material having a disordered crystalline structure. In one embodiment, the solid electrolyte material may include a crystalline structure containing stacking faults. In another embodiment, the solid electrolyte material may include a crystalline phase including a crystalline structure represented by a space group of the hexagonal crystal system or a space group of the rhombohedral lattice system. In another embodiment, the solid electrolyte material may include a crystalline phase including a crystalline structure represented by a monoclinic space group and a unit cell containing a reduced number of halogen atoms.

Description

Technical Field

[0001] The following relates to electrolyte materials and methods of forming the same, and more particularly to solid electrolyte materials including disorder in a crystalline structure and methods of forming the same. Background Art

[0002] Compared to conventional lithium-ion batteries, solid-state lithium batteries are expected to provide higher energy density, faster charging times, and reduced safety concerns by enabling a lithium metal anode. The industry continues to demand improved solid electrolyte materials. Brief Description of the Drawings

[0003] The present disclosure can be better understood by reference to the accompanying drawings, and many of the features and advantages of the present disclosure will be apparent to those skilled in the art.

[0004] Figure 1A Illustration of a crystalline structure including an exemplary solid electrolyte material according to one embodiment.

[0005] Figure 1B Illustration of another crystalline structure.

[0006] Figure 1C Illustration of a crystalline structure including another exemplary solid electrolyte material according to one embodiment.

[0007] Figure 2A Illustration of yet another crystalline structure.

[0008] Figure 2B Illustration of another crystalline structure.

[0009] Figure 2C Illustration of a crystalline structure including another exemplary solid electrolyte material according to one embodiment.

[0010] Figure 2D Illustration of a crystalline structure including another exemplary solid electrolyte material according to one embodiment.

[0011] Figure 3 Illustration of a crystalline structure.

[0012] Figure 4 Illustration of another crystalline structure.

[0013] Figure 5 Illustration of different crystalline structures.

[0014] Figures 6A to 6C Spectrum of an X-ray powder diffraction simulation of a halide-based material.

[0015] Figures 7A to 7ESpectra of X-ray diffraction simulations including different halide-based electrolyte materials.

[0016] Figure 8 Including a flowchart showing a method of forming a solid electrolyte material according to an embodiment.

[0017] Figure 9 Including an illustration of an X-ray diffraction pattern of a halide-based electrolyte material.

[0018] Figures 10 to 13 Including a crystal structure model of a solid electrolyte material.

[0019] Figure 14A and 14B Including an illustration of an X-ray diffraction pattern of a halide-based electrolyte material.

[0020] Figure 15 Including an illustration of an X-ray diffraction pattern of a sample of a halide-based electrolyte material.

[0021] Figure 16 Including an illustration of an X-ray diffraction pattern of a halide-based electrolyte material.

[0022] Those skilled in the art should recognize that, for simplicity and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be enlarged relative to other elements to help enhance the understanding of the embodiments of the present invention. In different figures, the same reference symbols are used to represent similar or identical items. Detailed Description

[0023] The following description provided in conjunction with the accompanying drawings is to assist in understanding the teachings disclosed herein. The following discussion will focus on the specific embodiments and examples of the teachings. This focus is provided to assist in describing the teachings and should not be construed as a limitation on the scope or applicability of the teachings.

[0024] As used herein, the terms "consisting of", "including", "comprising", "having", "with" or any other variation thereof are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features is not necessarily limited to those features, but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Additionally, unless otherwise expressly stated, "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following can satisfy condition A or B: A is true (or present) while B is false (or absent), A is false (or absent) while B is true (or present), and both A and B are true (or present).

[0025] The terms "a" or "an" are used to describe the elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. Unless clearly stated otherwise, such description shall be understood to include one or at least one, and the singular also includes the plural, or vice versa.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not restrictive.

[0027] Embodiments herein relate to solid electrolyte materials comprising halide-based electrolyte materials that include specific disorder in the crystal structure. Compared to another material having the same composition but without disorder, the solid electrolyte materials exhibit improved properties. The improved properties can include ionic conductivity, mechanical properties including deformability or plasticity, electrochemical stability, chemical stability, thermal stability, resistivity, particle morphology and / or size, electrode wettability, etc., or any combination thereof. The solid electrolyte materials can be used in electrochemical devices such as solid-state lithium-ion batteries. Embodiments further relate to methods of forming solid electrolyte materials having specific disorder in the crystal structure. The methods can allow control of the formation of disorder in the crystal structure and, at the same time, allow control of the crystallinity of the materials.

[0028] In one embodiment, the solid electrolyte material can include a halide-based electrolyte material represented by M 3-z (Me k+ ) f X 3-z+k*f where -3 ≤ z < 3; k is the valence of Me and 2 ≤ k < 6; 0 ≤ f ≤ 1; M includes alkali metals, Me includes metals other than alkali metals, and X includes halogens. In yet another embodiment, the halide-based electrolyte material can be a composite metal halide. In a particular aspect, f is not zero. In instances where Me includes more than one metal element, k can be the average of the total valences of each Me metal element. For example, when Me includes equimolar amounts of a trivalent element and a tetravalent element, k = (3 + 4) / 2 = 3.5. In a particular aspect, k can be 2 or 3 or 4 or 5.

[0029] After reading this application, those skilled in the art will understand that atomic vacancies can exist within the unit cell of the halide-based material. To assist in understanding the crystal structure, atomic vacancies can be added to the formula of the halide-based material, and the formula including atomic vacancies can be M 3-z (Me k+ ) f · y X 3-z+k*f, where · represents atomic vacancies within the unit cell, and y is the number of atomic positions of the vacancies. In a particular embodiment, y can be f*(k - 1).

[0030] In one aspect, M can include at least one of Li and Na. For example, M can include Li, Na, or a combination thereof. In another aspect, M can include Li, Na, K, Rb, Cs, or any combination thereof. In yet another aspect, M can consist of one or more alkali metal elements. For example, M can consist essentially of one or more alkali metal elements selected from the group consisting of Li, Na, K, Rb, and Cs. In another example, M can consist of Li. In yet another instance, M can consist of a combination of Li and at least one of Na, K, Rb, and Cs. In yet another instance, M can consist of Na and at least one of Cs and Rb. In another instance, M can consist of at least one of Na and Cs.

[0031] In another aspect, Me can include alkaline earth metal elements, 3d transition metals, rare earth elements, Zn, Zr, Hf, Ti, Sn, Th, Ge, V, Ta, Nb, Mo, W, Sb, Te, In, Bi, Al, Ga, Cu, or any combination thereof. For example, Me can include alkaline earth metal elements, which include Mg, Ca, Sr, or Ba, Zn, Cu, or any combination thereof. In another example, Me can include rare earth elements. In a particular embodiment, Me can consist of one or more rare earth elements among rare earth elements. In another particular example, Me can include Y, Ce, Gd, Er, Zr, La, Cu, Yb, In, Mg, Zn, Sn, or any combination thereof.

[0032] In one aspect, X can include halogens, which include Cl, Br, I, or any combination thereof. In one example, X can include at least one of Cl and Br. In a particular embodiment, X can consist of Cl, Br, or a combination thereof. In a particular example, X can be one or more halogens.

[0033] In another embodiment, the halide-based material can include a phase containing NH4 + . In a particular aspect, the halide-based material can be (NH4) n M 3-z (Me k+ ) f X n+3-z+k*fIt is represented, where n > 0. Symbolic letters, such as M, Me, n, f, Z, X, and k, are used in the formulas of the embodiments herein. As used in this disclosure, the same symbolic letters mentioned in different embodiments are intended to refer to the same or similar elements or values. When the same symbolic letters are used, the specific elements or values described for the symbolic letters in one embodiment can be applied to another embodiment. For example, the descriptions of M, Me, X, f, z, and k in the above embodiments can be applied to this embodiment and other embodiments of this disclosure.

[0034] In a specific embodiment, the halide-based electrolyte material can be represented by Li 3-z Me k+ X 3-z+k It is represented. When z is not 0, the complex metal halide can be non-stoichiometric. When z is 0, the complex metal halide can be stoichiometric. In a specific instance, -0.95 ≤ z ≤ 0.95. In another specific instance, Me includes Y, Gd, Yb, Zr, In, Sc, Zn, Mg, Ca, Ba, Sn, or a combination thereof, and X is Cl, Br, or a combination thereof.

[0035] In yet another embodiment, the halide-based electrolyte material can be represented by Li3MeBr6. In yet another embodiment, the halide-based electrolyte material can be represented by Li3MeCl6. In a specific example, Me can be composed of at least one metal element with a valence of 3. In another specific example, Me can include one or more metal elements, where the average valence of the one or more metal elements is 3.

[0036] In another specific embodiment, the halide-based electrolyte material can be composed of Li, Y, and at least one of Cl and Br. For example, the halide-based electrolyte material can be composed of Li, Y, and Cl. In another example, the halide-based electrolyte material can be composed of Li, Y, and Br. In yet another example, the halide-based electrolyte material can be composed of Li, Y, Cl, and Br. In a specific example, the halide-based electrolyte material can be represented by Li 3x Y 1-x Cl3 or Li 3x Y 1-x Br3, where 0 < x < 0.5.

[0037] In another specific embodiment, the halide-based electrolyte material may consist of Li, Gd, and at least one of Cl and Br. For example, the halide-based electrolyte material may consist of Li, Gd, and Cl. In another example, the halide-based electrolyte material may consist of Li, Gd, and Br. In yet another example, the halide-based electrolyte material may consist of Li, Gd, Cl, and Br. In a specific example, the halide-based electrolyte material may consist of Li 3x Gd 1- x Cl3 or Li 3x Gd 1-x Br3, where 0.01 ≤ x < 1.

[0038] Specific examples of the halide-based materials may include Li3YCl6, Li3YBr6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.8 Y 0.8 Sn 0.2 Cl6, Li 3.2 Y 0.8 Zn 0.2 Cl6, Li 3.2 Y 0.8 Mg 0.2 Cl6, Li3Y 1 / 3 Zr 1 / 3 Mg 1 / 3 Cl6, Li3Y 1 / 3 Sn 1 / 3 Mg 1 / 3Cl6, Li3Y 1 / 3 Zr 1 / 3 Zn 1 / 3 Cl6, Li 2.95 Na 0.05 YBr6, Li 2.95 K 0.05 YBr6, Li 2.95 Cs 0.05 YBr6, Li3Y 0.7 Gd 0.3 Br6, Li3Y 0.8 Yb 0.2 Br6, Li3Y 0.9 La 0.1 Br6, Li 2.9 Y 0.9 Ce 0.1 Br6 or Li3Y(Cl,Br)6.

[0039] In one embodiment, the halide-based electrolyte material can include a crystalline phase that includes a crystalline structure different from a conventional crystalline structure. For example, the crystalline structure can include disorder compared to a conventional crystalline structure. As used herein, a conventional structure is intended to refer to an ordered crystalline structure of a halide-based material having the same composition. The crystalline structure can include characteristics including a crystal system, a lattice system, a space group, one or more unit cell parameters, the one or more unit cell parameters including unit cell volume, the values of a, b, c, or any combination thereof, the number of atoms within the unit cell, a stacking order, atomic vacancies, occupancy of the vacancies, or any combination thereof. The disorder can be a change in order associated with any of the characteristics.

[0040] In one embodiment, the halide-based electrolyte material can include a crystalline structure that includes a layered atomic arrangement, where the crystalline structure can include disorder. In one aspect, the crystalline structure can include atoms arranged in layers, where the stacking of the layers can include disorder. In one example, the crystalline structure can include stacking faults. A stacking fault represents a defect in the crystalline structure caused by a shift in the occupied or vacant atomic positions, which generates disorder of the crystal planes in the crystalline structure.

[0041] Briefly turning to Figure 1A 、 1B and 1C, different crystalline structures of halide-based materials having the same composition are shown. Figure 1A A diagram of a specific crystalline structure including an example of one embodiment; and Figure 1B includes a conventional crystalline structure of a halide-based material. Figure 1C A diagram of a specific crystalline structure including an example of another embodiment. Crystalline structures 100, 101, and 102 include layers containing atoms 110, 120, and 130. In structure 101, the positions of the same atoms (i.e., atoms 110, 120, or 130) in different layers remain the same in the stack, and the positions of atoms 110, 120, and 130 and vacancies 140 follow the same pattern across multiple layers in structure 101. As shown, structure 101 includes an ordered stack of atomic layers and vacancy layers. Stacking faults are included in structures 100 and 102 because at least some of the atomic positions of atoms 110, 120, or 130 are shifted compared to the positions of the same atoms in different layers or compared to the positions of the same atoms in structure 100. After reading this disclosure, those skilled in the art can understand that the shift of atomic positions across the layers of the crystal structure can be probabilistic, and the stacking faults of the halide-based material are not limited to Figure 1A and 1C shown in the specific examples. The halide-based materials of the embodiments herein can include structures greater than Figure 1B shown (0% or close to 0%) and as Figure 1A and1C Stacking faults of up to 100% as shown. Those skilled in the art can further understand that in Figure 1A and 1C only a small representative part of the structures 100, 101 and 102 are shown respectively.

[0042] In a particular embodiment, the halide-based material can include a crystalline structure containing a specific amount of stacking faults, which can be beneficial to improving the properties of the halide-based material. Stacking faults may cause changes in the powder X-ray diffraction pattern, in particular resulting in non-uniform broadening of only certain X-ray diffraction peaks. Stacking faults can be determined by powder X-ray diffraction analysis of the halide-based material and DIFFaX simulation and Rietveld refinement (by using software such as TOPAS 4.2 from Bruker Germany or FullProf (version 7.30, published in March 2020), or another version or software equivalent to TOPAS 4.2 or FullProf 7.30) according to the stacking fault quantification method described by Boulineau et al., Solid State Ionics 180 (2010) 1652–1659, the entire text of which is incorporated herein by reference. Briefly, the quantification method can include fitting a simulation to the X-ray diffraction pattern of the halide-based material powder. The simulation can define the main blocks of the crystalline structure. These main blocks can be composed of main wafers and inter-wafer spaces. Then, the main blocks can be stacked according to one of two or more possible stacking vectors. The unique occurrence of only one stacking vector in the stacking vectors results in perfect stacking, i.e., 0% stacking faults, such as Figure 1B the structure 101 as shown. The alternation of stacking vectors in the stacking direction of the crystalline structure produces stacking faults. The fitting of the simulation to the X-ray diffraction pattern of the halide-based material can include changing one or more parameters of the crystalline structure (also called "parameter refinement") and implementing a least squares variance minimization algorithm, and the stacking faults can be identified and quantified. Alternatively, after Rietveld refinement, the FAULTS software can be used instead of the stacking fault quantification method described by Boulineau.

[0043] In one aspect, the crystalline structure can include at least 20% stacking faults, such as at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% stacking faults. In another aspect, the stacking of atomic layers can be completely disordered. For example, the crystalline structure can include 100% stacking faults. In another aspect, the stacking faults can be at most 99%, such as at most 95%, at most 92%, at most 90%, at most 85%, at most 80%, at most 75% or at most 70%. Additionally, the crystalline structure can include stacking faults within a range including any of the minimum percentages and maximum percentages mentioned herein. In a specific example, the solid electrolyte material can include a halide-based material having a crystalline structure including at least 50%. In another specific example, the solid electrolyte material can include a halide-based material having greater than 50% and at most 100% stacking faults.

[0044] A specific example of the halide-based material can include lithium yttrium bromide, which includes at least 50% stacking faults.

[0045] In a specific embodiment, the halide-based material can include a monoclinic crystalline structure including stacking faults. In a specific aspect, the crystalline structure can be represented by the space group C2 / m. For example, the halide-based material can include lithium yttrium bromide, which includes a crystalline structure represented by C2 / m and includes stacking faults. In another embodiment, the halide-based material can include a crystalline structure of a rhombohedral lattice system or a hexagonal crystal system, which includes stacking faults.

[0046] Another specific example of the halide-based material can include at least 50% stacking faults in the stacking direction along the c-axis of the monoclinic unit cell, such that the three stacking vectors are (0; 0; 1) (1 / 2; -1 / 6; 1) and (1 / 6; -1 / 6; 1). Specific examples of such halide-based materials can include lithium yttrium bromide. The halide-based materials described in the examples herein having specific stacking faults can have improved properties, such as ionic conductivity. For example, compared to conventional lithium yttrium bromide, lithium yttrium bromide having at least 50% stacking faults can have improved ionic conductivity, which stacking faults are along the c-axis of the monoclinic unit cell according to the vectors (0; 0; 1) (1 / 2; -1 / 6; 1) and (1 / 6; -1 / 6; 1). The exemplary lithium yttrium halides of the examples herein can have an ionic conductivity of 1.7 mS / cm to 3.1 mS / cm at room temperature.

[0047] Compared with Figure 1B the further disorder of the positions of atoms 130 and vacancies 140 is also included inFigure 1A and 1C As shown in the figure, the position of atom 130 is highly mixed with the vacancy 140 in structures 100 and 102. Those skilled in the art can understand that structures 100 and 102 are novel crystalline structures generated from the highly mixed positions of atom 130 and the vacancy. As shown in a specific example of crystalline structure 100, atom 130 is highly mixed with vacancy 140. Similarly, atom 130 in crystalline structure 102 is highly mixed with vacancy 140. As shown in crystalline structure 101, there is an arrangement of the positions of atom 130 and vacancy 140 because atom 130 occupies a separate position from vacancy 140. Figures 1A to 1C This will be further discussed later in the present disclosure.

[0048] In another embodiment, the halide-based material may include a crystalline phase that includes a crystalline structure different from a conventional crystalline structure. In one aspect, the halide-based material may include a crystalline phase that has a crystalline structure represented by a space group different from a conventional crystalline structure. In a specific embodiment, the solid electrolyte material may include a halide-based material that includes a first crystalline phase and a second crystalline phase integrated at the atomic level, the nanodomain level, or both. The nearest atomic distance is typically less than 0.5 nm, and the nanodomain may have a size larger than the nearest atomic distance, such as greater than 1 nm. In one aspect, the halide-based material may include a first crystalline phase and a second crystalline phase, the first crystalline phase having a first crystalline structure represented by a first space group, the second crystalline phase having a second crystalline structure represented by a second space group different from the first space group, wherein at least the first crystalline structure represented by the first space group is different from a conventional crystalline structure. In particular, the first space group is different from the space group of the conventional crystalline structure.

[0049] In a particular aspect, the halide-based material can include a first crystalline phase at a particular concentration, which is beneficial for improving the properties of the solid electrolyte material. For example, the solid electrolyte material can include a halide-based material having a first crystalline phase at a concentration of at least 1 wt% of the total weight of the halide-based material, such as at least 4 wt%, at least 5 wt%, at least 8 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt% or at least 90 wt%. In yet another example, the halide-based material can include a first phase at a concentration of at most 95 wt%, such as at most 90 wt%, at most 85 wt%, at most 80 wt%, at most 70 wt%, at most 65 wt%, at most 60 wt%, at most 55 wt%, at most 50 wt%, at most 45 wt%, at most 40 wt%, at most 30 wt%, at most 25 wt%, at most 15 wt%, at most 8 wt% or at most 5 wt%. Additionally, the halide-based material can include a first phase at a concentration within a range including any of the minimum and maximum percentages mentioned herein.

[0050] In another aspect, the halide-based material can include a second phase at a specific concentration, which can be beneficial for improving the properties of the solid electrolyte material. In one example, for instance, the solid electrolyte material can include a halide-based material having a second crystalline phase at a concentration of at least 1 wt%, such as at least 4 wt%, at least 5 wt%, at least 8 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt% or at least 90 wt% of the total weight of the halide-based material. In yet another example, the halide-based material can include a second phase at a concentration of at most 95 wt%, such as at most 90 wt%, at most 85 wt%, at most 80 wt%, at most 70 wt%, at most 65 wt%, at most 60 wt%, at most 55 wt%, at most 50 wt%, at most 45 wt%, at most 40 wt%, at most 30 wt%, at most 25 wt%, at most 15 wt%, at most 8 wt% or at most 5 wt%. Additionally, the halide-based material can include a second phase at a concentration within a range including any of the minimum and maximum percentages mentioned herein. In an exemplary embodiment, the second phase can have a conventional crystalline structure. In a further exemplary embodiment, the second phase can have a second crystalline structure different from the conventional structure, and in a particular embodiment, the second space group can be different from the space group of the conventional structure.

[0051] In yet another aspect, the halide-based material can include a third phase having a third crystalline structure, which includes crystalline structure features different from the second and / or first crystalline structures. In a particular aspect, the third crystalline structure can be represented by a third space group different from the first and second space groups. In yet another aspect, the halide-based material can include a third phase at any concentration described in terms of the concentration relative to the first or second phase. In yet another aspect, the halide-based material can include an amorphous phase. The concentration of the amorphous phase can be at most 10 wt%, or at most 5 wt% or at most 1 wt%. It should be understood that the total concentration of each phase included in the halide-based material constitutes 100 wt%.

[0052] In another embodiment, the halide-based material can consist essentially of a crystalline phase having a crystalline structure represented by a space group different from the space group of the conventional crystalline structure.

[0053] In a particular embodiment, the solid electrolyte material may include a halide-based material, the halide-based material including a first phase having a first crystal structure represented by a first space group, wherein the first space group may be a space group of the rhombohedral lattice system. The rhombohedral lattice system includes 7 space groups, the space groups including R3, R-3, R32, R3m, R3c, R-3m, and R-3c space groups. In a particular aspect, the first crystal phase may have a first crystal structure represented by the R-3m space group. In another aspect, the second crystal phase may be represented by a space group of the monoclinic system. In a particular aspect, the second phase may include a crystal structure represented by C2 / m. Particular examples of the halide-based material may include a crystal phase having a crystal structure represented by R-3m and a crystal phase having a crystal structure represented by C2 / m. Yet another particular example of the halide-based material may consist of a first crystal phase having a crystal structure represented by R-3m and a second crystal phase having a crystal structure represented by C2 / m. Yet another particular example of the halide-based material may consist of a first crystal phase having a crystal structure represented by R-3m, a second crystal phase having a crystal structure represented by C2 / m, and a third crystal phase having a crystal structure represented by Fd-3m or Fm-3m. In another particular example, the halide-based material may consist of a crystal phase having a crystal structure represented by R-3m.

[0054] See Figure 1A , 1B and 1C, Figure 1A including an illustration of a particular example of the crystal structure represented by R-3m of one embodiment, Figure 1B including an illustration of a conventional crystal structure represented by C2 / m, and Figure 1C including an illustration of the crystal structure represented by the C2 / m space group of one embodiment. In a particular example, the halide-based electrolyte material may include lithium yttrium bromide, the lithium yttrium bromide including a first phase having a crystal structure represented by R-3m, as Figure 1A shown, and a second phase having a crystal structure represented by C2 / m, as Figure 1B shown, wherein the first crystal phase and the second crystal phase are integrated at the atomic level, the nanodomain level, or both. In another particular example, the halide-based solid electrolyte material may include lithium yttrium bromide, the lithium yttrium bromide may consist of a crystal phase having a crystal structure represented by R-3m, as Figure 1A shown.

[0055] In another embodiment, the solid electrolyte material may include a halide-based material, the halide-based material including a phase having a crystal structure represented by a space group of the hexagonal system. The hexagonal system includes 27 space groups, including P6, P61, P65, P62, P64, P63, P6 / m, P63 / m, P622, P6122, P6522, P6222, P6422, P6322, P6mm, P6cc, P63cm, P63mc, P6 / mmm, P6 / mcc, P63 / mcm, and P63 / mmc. In one aspect, the halide-based material can include a crystalline phase having a crystalline structure represented by any one of the space groups in the hexagonal crystal system. In a particular aspect, the halide-based material can include a crystalline phase having a crystalline structure represented by P63 / mcm. In another aspect, the halide-based material can include a crystalline phase having a crystalline structure represented by the P63 / mmc space group. In a particular aspect, the solid electrolyte material can consist essentially of a crystalline phase having a crystalline structure represented by P63 / mcm. In another particular aspect, the solid electrolyte material can consist essentially of a crystalline phase having a crystalline structure represented by the P63 / mmc space group.

[0056] In another embodiment, the halide-based material can include a first crystalline phase having a first crystalline structure represented by the space group of a hexagonal crystalline structure and a second phase having a second crystalline structure represented by the space group of a crystal system other than the hexagonal crystalline structure. In one aspect, the second phase can have a crystalline structure represented by the space group of the trigonal crystal system. In a particular aspect, the second phase can have a second crystalline structure represented by P-3m1. In yet another aspect, the second phase can have a crystalline structure represented by the space group of an orthorhombic crystalline structure. In another particular aspect, the second phase can have a second crystalline structure represented by the Pnma space group.

[0057] In a particular embodiment, the halide-based electrolyte material can include a first phase having a first crystalline structure represented by P63 / mcm or P63 / mmc and a second phase having a second crystalline structure represented by P-3m1 or Pnma. In yet another particular embodiment, the halide-based electrolyte material can consist of a first phase having a first crystalline structure represented by P63 / mcm or P63 / mmc and a second phase having a second crystalline structure represented by P-3m1 or Pnma.

[0058] See Figures 2A to 2D , Figure 2A a diagram showing a crystalline structure 200 represented by Pnma, Figure 2B a diagram showing a crystalline structure 201 represented by P-3m1, and Figure 2C a diagram showing a crystalline structure 202 represented by P63 / mcm for a specific example of an embodiment. Figure 2D a diagram showing a crystalline structure 203 represented by P63 / mmc for a specific example of an embodiment.

[0059] In a specific example, the halide-based electrolyte material can include lithium yttrium chloride, which includes a first phase having a crystal structure represented by P63 / mcm (as shown in Figure 2C shown) or P63 / mmc (as shown in Figure 2D shown), and a second phase having a crystal structure represented by Pnma (as shown in Figure 2A shown) or P-3m1 (as shown in Figure 2B shown), where the first crystal phase and the second crystal phase are integrated at the atomic level, the nanodomain level, or both. In another specific example, the halide-based solid electrolyte material can include lithium yttrium chloride, which can be composed of a crystal phase having a crystal structure represented by P63 / mcm (as shown in Figure 2C shown) or P63 / mmc (as shown in Figure 2D shown). In another specific example, the halide-based solid electrolyte material can include lithium yttrium chloride, which can include a first phase having a crystal structure represented by P63 / mcm (as shown in Figure 2C shown) or P63 / mmc (as shown in Figure 2D shown), and a second phase having a crystal structure represented by Pnma (as shown in Figure 2A shown) or P-3m1 (as shown in Figure 2B shown).

[0060] In one embodiment, the solid electrolyte material can include a halide-based material containing a crystal structure that includes a different number of atoms in the unit cell compared to a conventional crystal structure. In one aspect, the halide-based material can include a crystal structure that contains a disordered unit cell compared to a conventional structure. In yet another aspect, the disordered unit cell can differ from the conventional crystal structure in terms of the number of halogen atoms, the number of atoms of M (such as Li), the number of atoms of Me, the unit cell parameters, the volume of the unit cell (such as a smaller unit cell), or any combination thereof. In another aspect, the halide-based material can include a crystal structure that includes a unit cell containing fewer halogen atoms compared to a conventional crystal structure.

[0061] In another specific embodiment, the halide-based material may include a crystalline structure that includes a unit cell containing fewer than 12 halogen atoms. In one aspect, the number of halogen atoms in the unit cell may be at most 10, at most 8, at most 6, at most 5, or at most 4. In another aspect, the number of halogen atoms in the unit cell may be at least 1, at least 2, at least 3, or at least 4. Additionally, the halide-based material may include a crystalline structure that includes a unit cell that includes halogen atoms within a range including any of the minimum and maximum values mentioned herein. For example, the halide-based material may include 2 to 6 halogen atoms in the unit cell.

[0062] In yet another embodiment, the halide-based material may include a crystalline structure that is represented by the monoclinic space group and includes a unit cell having disorder. In one aspect, the space group may be C2 / m. In another aspect, the unit cell may include fewer than 12 halogen atoms. In a specific aspect, the halide-based material may include a crystalline structure that is represented by the monoclinic space group and includes a unit cell containing 3 to 5 halogen atoms.

[0063] In yet another embodiment, the halide-based material may include a crystalline structure represented by a space group of the hexagonal crystal system, wherein the unit cell may include a halogen count less than 12. In one aspect, the space group may be R-3m. In another aspect, the unit cell may include at most 8 halogen atoms. In at least one specific aspect, the halide-based material may include a crystalline structure represented by a space group of the hexagonal crystal system and includes a unit cell having at most 6 halogen atoms. In another aspect, the halide-based material may include a crystalline structure represented by a space group of the hexagonal crystal system and includes a unit cell having at least 1.5 halogen atoms.

[0064] In yet another embodiment, the halide-based material may include a crystalline structure represented by a space group of the rhombohedral lattice system, wherein the unit cell may include a halogen count less than 12. In one aspect, the unit cell may include at most 8 halogen atoms.

[0065] A conventional C2 / m unit cell includes 12 halogen atoms. For example, conventional Li3MeBr6, such as Li3YBr6, includes 12 bromine atoms in the unit cell. A representative example of Li3YBr6 of one embodiment may include fewer than 12 bromine atoms, such as at most 6 bromine atoms or at most 4 bromine atoms. A specific example of Li3YBr6 may have a smaller monoclinic unit cell that has 4 Br atoms. Another specific example of Li3YBr6 of one embodiment may include an R-3m unit cell containing 6 Br atoms.

[0066] In one embodiment, the solid electrolyte material may include a halide-based material that includes a crystalline structure having specific unit cell characteristics. In one aspect, the halide-based material may include a unit cell, where the unit cell parameters a, b, and c may independently have specific values A, B, and C, respectively. In another aspect, the unit cell may include a specific volume, a specific normalized volume, or any combination thereof.

[0067] In a specific embodiment, the halide-based material may include a crystalline structure represented by the rhombohedral space group, where the unit cell parameters a and b may be equal. Referring Figure 3 , a rhombohedral unit cell 300 including parameters a, b, and c is shown. In a specific aspect, the unit cell may be of the R-3m space group. In one aspect, A or B or both may include a specific value. For example, A or B may be at least 3.0 Å, at least 3.3 Å, at least 3.6 Å, or at least 3.9 Å. In another example, A or B may be at most 4.8 Å, at most 4.6 Å, at most 4.3 Å, at most 4.2 Å, or at most 4.0 Å. Additionally, A or B may be within a range including any of the minimum and maximum values mentioned herein. In yet another aspect, the halide-based material may include a crystalline structure including a specific C. In one example, C may be at least 15 Å, at least 17 Å, or at least 19 Å. In another example, C may be at most 21 Å, at most 20.2 Å, or at most 19.5 Å. Additionally, C may be within a range including any of the minimum and maximum values mentioned herein.

[0068] In yet another aspect, the rhombohedral unit cell may include a unit cell volume V having a specific value. For example, V may be at least 200 ų, at least 210 ų, at least 230 ų, at least 250 ų, or at least 260 ų. In another example, V may be at most 320 ų, at most 310 ų, at most 290 ų, at most 275 ų, or at most 270 ų. In a specific example, V may be within a range including any of the minimum and maximum values mentioned herein.

[0069] In yet another aspect, the rhombohedral unit cell may include a normalized volume that includes the unit volume V per formula unit N / FU , where V N / FU = V / N FU , where N FU represents the number of formula units in the unit cell. In a specific aspect, the unit cell may include a specific V N / FU . In one example, the halide-based material may include a crystalline structure that includes a V of at least 200 ų, at least 210 ų, at least 230 ų, at least 250 ų, or at least 260 ų N / FU . In another example, VN / FU can be at most 290 cubic angstroms, at most 275 cubic angstroms, at most 270 cubic angstroms, or at most 268 cubic angstroms. In a particular example, V N / FU can be in a range that includes any of the minimum and maximum values mentioned herein.

[0070] In yet another aspect, the rhombohedral unit cell can include a normalized volume that includes a unit volume V N / AA for each halogen atom, where V N / AA = V / N AA and N AA represents the number of halogen atoms in the unit cell. In a particular aspect, the halide-based material can include a crystalline structure that includes a specific V N / AA . In one example, V N / AA can be at least 30 cubic angstroms, at least 34 cubic angstroms, at least 38 cubic angstroms, at least 42 cubic angstroms, or at least 46 cubic angstroms. In another example, V N / AA can be at most 50 cubic angstroms, at most 48 cubic angstroms, or at most 47 cubic angstroms. In a particular example, V N / AA can be in a range that includes any of the minimum and maximum values mentioned herein.

[0071] In a particular embodiment, the halide-based material can include a crystalline structure represented by the monoclinic space group, where the unit cell includes a reduced volume compared to a conventional crystalline structure. Referring Figure 4 to, a monoclinic unit cell 400 including parameters a, b, and c is shown, where a, b, and c are different from each other. In a particular aspect, the unit cell can be of the C2 / m space group. In one aspect, A, B, and C can independently include specific values. For example, A can be at least 5.8 angstroms, at least 6.1 angstroms, at least 6.3 angstroms, at least 6.5, at least 6.7, or at least 6.9 angstroms. In another instance, A can be at most 7.8 angstroms, at most 7.6 angstroms, at most 7.3 angstroms, at most 7.2 angstroms, or at most 7.0 angstroms. Additionally, A can be in a range that includes any of the minimum and maximum values mentioned herein. In yet another example, B can be at least 3.0 angstroms, at least 3.3 angstroms, at least 3.6 angstroms, or at least 3.9 angstroms. In another instance, B can be at most 4.8 angstroms, at most 4.6 angstroms, at most 4.3 angstroms, at most 4.2 angstroms, or at most 4.1 angstroms. Additionally, B can be in a range that includes any of the minimum and maximum values mentioned herein. In one example, C can be at least 6.1 angstroms, at least 6.4 angstroms, or at least 6.8 angstroms. In another instance, C can be at most 7.9 angstroms, at most 7.6 angstroms, at most 7.2 angstroms, or at most 6.9 angstroms. Additionally, C can be in a range that includes any of the minimum and maximum values mentioned herein.

[0072] In yet another aspect, the monoclinic unit cell may include a unit cell volume V having a specific value. For example, V may be at least 110 cubic angstroms, at least 125 cubic angstroms, at least 140 cubic angstroms, at least 160 cubic angstroms, or at least 170 cubic angstroms. In another example, V may be at most 500 cubic angstroms, at most 400 cubic angstroms, at most 310 cubic angstroms, at most 250 cubic angstroms, at most 220 cubic angstroms, at most 200 cubic angstroms, or at most 180 cubic angstroms. In a specific example, V may be in a range including any of the minimum and maximum values mentioned herein.

[0073] In a specific aspect, the monoclinic unit cell may include a specific V N / FU . In one example, the halide-based material may include a crystal structure that includes a V of at least 200 cubic angstroms, at least 210 cubic angstroms, at least 230 cubic angstroms, at least 250 cubic angstroms, or at least 260 cubic angstroms N / FU . In another example, V N / FU may be at most 320 cubic angstroms, at most 300 cubic angstroms, at most 280 cubic angstroms, or at most 270 cubic angstroms. In a specific example, V N / FU may be in a range including any of the minimum and maximum values mentioned herein.

[0074] In yet another aspect, the monoclinic unit cell may include a normalized volume that includes a unit volume V per halogen atom N / AA , where V N / AA = V / N AA and N AA represents the number of halogen atoms in the unit cell. In a specific aspect, the halide-based material may include a crystal structure comprising a specific V N / AA . In one example, V N / AA may be at least 30 cubic angstroms, at least 34 cubic angstroms, at least 38 cubic angstroms, at least 42 cubic angstroms, or at least 44 cubic angstroms. In another example, V N / AA may be at most 54 cubic angstroms, at most 51 cubic angstroms, at most 49 cubic angstroms, or at most 47 cubic angstroms or at most 45 cubic angstroms. In a specific example, V N / AA may be in a range including any of the minimum and maximum values mentioned herein.

[0075] The conventional crystal structure of Li3YBr6 is represented by the C2 / m space group and includes 2 formula units per unit cell, Li3YBr6, 12 Br atoms, and a V of approximately 534 cubic angstroms. An exemplary Li3YBr6 of one embodiment can include a crystal structure represented by the R-3m space group and 1 formula unit per unit cell, 6 Br atoms, and a V of approximately 267 + / - 3% cubic angstroms. Another exemplary Li3YBr6 of one embodiment can include a crystal structure represented by the C2 / m space group and 2 / 3 formula units per unit cell, 4 Br atoms, and a V of approximately 178 + / - 3% cubic angstroms.

[0076] In another embodiment, the halide-based material can include a crystal structure represented by the hexagonal space group, where the unit cell parameters a and b can be equal. Referring Figure 5 , a hexagonal unit cell 500 including the parameters a, b, and c is shown. In one aspect, the hexagonal unit cell can be represented by the P63 / mcm space group. In another aspect, the hexagonal unit cell can be represented by the P63 / mmc space group.

[0077] In one aspect, the P63 / mcm unit cell can include a specific A, B, or C. In one example, A or B or both can be at least 5.0 angstroms, at least 5.5 angstroms, at least 6.1 angstroms, or at least 6.3 angstroms. In another aspect, A or B or both can be at most 8 angstroms, or at most 7.5 angstroms, or at most 7.0 angstroms, or at most 6.5 angstroms. Additionally, A, B, or both can be within a range including any of the minimum and maximum values mentioned herein. In yet another aspect, the halide-based material can include a crystal structure including a specific C. In one example, C can be at least 4.8 angstroms, at least 5.3 angstroms, at least 5.7 angstroms, or at least 6.0 angstroms. In one example, C can be at most 6.9 angstroms, at most 6.4 angstroms, or at most 6.1 angstroms. In yet another example, C can be within a range including any of the minimum and maximum values mentioned herein.

[0078] In yet another aspect, the P63 / mcm unit cell can include a unit cell volume V having a specific value. For example, V is at least 150 cubic angstroms, at least 170 cubic angstroms, at least 190 cubic angstroms, at least 205 cubic angstroms, or at least 210 cubic angstroms. In yet another example, V can be at most 270 cubic angstroms, at most 250 cubic angstroms, at most 230 cubic angstroms, or at most 220 cubic angstroms. In a specific example, V can be within a range including any of the minimum and maximum values mentioned herein.

[0079] In a specific aspect, the P63 / mcm unit cell can include a specific V N / FU. In one example, the halide-based material can include a crystalline structure that includes a V of at least 150 cubic angstroms, at least 170 cubic angstroms, at least 190 cubic angstroms, at least 200 cubic angstroms, or at least 210 cubic angstroms N / FU . In another example, V N / FU can be at most 270 cubic angstroms, at most 250 cubic angstroms, at most 230 cubic angstroms, or at most 220 cubic angstroms. In a specific example, V N / FU can be in the range including any of the minimum and maximum values mentioned herein.

[0080] In yet another aspect, the P63 / mcm unit cell can include a normalized volume that includes a unit volume V of each halogen atom N / AA , where V N / AA = V / N AA and N AA represents the number of halogen atoms in the unit cell. In a specific aspect, the halide-based material can include a crystalline structure containing a specific V N / AA . In one example, V N / AA can be at least 25 cubic angstroms, at least 28 cubic angstroms, at least 31 cubic angstroms, at least 34 cubic angstroms, or at least 36 cubic angstroms. In another example, V N / AA can be at most 50 cubic angstroms, at most 47 cubic angstroms, at most 44 cubic angstroms, or at most 41 cubic angstroms or at most 38 cubic angstroms. In a specific example, V N / AA can be in the range including any of the minimum and maximum values mentioned herein.

[0081] In one aspect, the P63 / mmc unit cell can include a specific A, B, or C. In one example, A or B or both can be at least 2.5 angstroms, at least 2.8 angstroms, at least 3.2 angstroms, or at least 3.6 angstroms. In another aspect, A or B or both can be at most 5 angstroms, at most 4.6 angstroms, at most 4.3 angstroms, at most 4.1 angstroms, or at most 3.8 angstroms. Additionally, A, B, or both can be in the range including any of the minimum and maximum values mentioned herein. In yet another aspect, the halide-based material can include a crystalline structure containing a specific C. In one example, C can be at least 4.8 angstroms, at least 5.3 angstroms, at least 5.7 angstroms, or at least 6.0 angstroms. In one example, C can be at most 6.9 angstroms, at most 6.4 angstroms, or at most 6.1 angstroms. In yet another example, C can be in the range including any of the minimum and maximum values mentioned herein.

[0082] In yet another aspect, the P63 / mmc unit cell can include a unit cell volume V having a specific value. For example, V can be at least 60 cubic angstroms, at least 65 cubic angstroms, at least 68 cubic angstroms, or at least 70 cubic angstroms. In another example, V can be at most 85 cubic angstroms, at most 82 cubic angstroms, at most 78 cubic angstroms, at most 74 cubic angstroms, or at most 71 cubic angstroms. In yet another example, V can be in a range including any of the minimum and maximum values mentioned herein.

[0083] In a specific aspect, the P63 / mmc unit cell can include a specific V N / FU . In one example, a halide-based material can include a crystal structure that includes a V of at least 150 cubic angstroms, at least 170 cubic angstroms, at least 190 cubic angstroms, at least 200 cubic angstroms, or at least 210 cubic angstroms. N / FU . In another example, V N / FU can be at most 270 cubic angstroms, at most 250 cubic angstroms, at most 230 cubic angstroms, or at most 220 cubic angstroms. In a specific example, V N / FU can be in a range including any of the minimum and maximum values mentioned herein.

[0084] In yet another aspect, the P63 / mmc unit cell can include a normalized volume that includes a unit volume V per halogen atom N / AA , where V N / AA = V / N AA and N AA represents the number of halogen atoms in the unit cell. In a specific aspect, a halide-based material can include a crystal structure containing a specific V N / AA . In one example, V N / AA can be at least 25 cubic angstroms, at least 28 cubic angstroms, at least 31 cubic angstroms, at least 34 cubic angstroms, or at least 36 cubic angstroms. In another example, V N / AA can be at most 50 cubic angstroms, at most 47 cubic angstroms, at most 44 cubic angstroms, or at most 41 cubic angstroms or at most 38 cubic angstroms. In a specific example, V N / AA can be in a range including any of the minimum and maximum values mentioned herein.

[0085] The conventional crystal structure of Li3YCl6 is represented by the Pnma space group and includes 4 formula units per unit cell, 24 Cl atoms, and a V of about 875 cubic angstroms. Another conventional crystal structure of Li3YCl6 is represented by the P-3m1 space group and includes 3 formula units per unit cell, 18 Cl atoms, and a V of about 655 cubic angstroms. An exemplary Li3YCl6 of an embodiment may include a crystal structure represented by P63 / mcm and includes 1 formula unit per unit cell, 6 Cl atoms, and a V of 218+ / -3% cubic angstroms. Another exemplary Li3YCl6 of an embodiment may include a crystal structure represented by the P63 / mmc space group and 1 / 3 formula unit per unit cell, 2 Cl atoms, and a V of 73+ / -3% cubic angstroms.

[0086] In one embodiment, the solid electrolyte material may include a halide-based material having a disordered crystal structure, the disordered crystal structure including atomically disordered vacancies and Me atom positions; disordered X1 and X2 atoms, where X1 and X2 represent two different halogen atoms; disordered vacancy positions and M atoms; disordered M and Me atoms; disordered M, Me, and vacancy atoms; or any combination thereof.

[0087] In another embodiment, the halide-based material may include a crystal structure including vacancies and Me atoms, where at least some of the positions of the vacancies and Me atoms may be disordered in an atomic layer or a linear atomic chain. In one aspect, the halide-based material may include a crystal structure including atomic disorder in the positions of the vacancies and Me atoms, where the disorder may be at least 10%, at least 20%, at least 30%, at least 40%, at least 60%, at least 80%, or at least 90%.

[0088] Atomic disorder can be determined by Rietveld refinement of the X-ray powder diffraction pattern of the halide-based material, and more specifically, based on the occupancy percentages of the crystal positions including M atoms, Me atoms, and vacancies. After reading this application, those skilled in the art can understand that atomic disorder based on the occupancy percentages of crystal positions can be determined on a case-by-case basis according to the following steps.

[0089] X-ray diffraction (XRD) analysis can be performed on the powder halide-based material, and the XRD pattern can be recorded. The simulated XRD pattern can be fitted and matched with the XRD of the halide-based material by refining a set of crystal structure parameters (e.g., unit cell parameters, atomic vacancies, and other parameters mentioned in this application) to obtain the best fit and determine the occupancy rate of the crystal positions. Then, atomic disorder can be determined based on the occupancy rate of the crystal positions.

[0090] Li3MeBr6 is used herein as an example of a halide-based material. Vacancies in the crystal structure can be included in the formula, and the halide-based material can be represented by Li3Me· oct 2Br6. The Li3MeBr6 of the examples herein can have a crystal structure represented by the R-3m space group. When the occupancy of the Me position is 33.33%, the crystal structure can have octahedral vacancies· oct and perfect atomic disorder at the positions of Me atoms, i.e., 100% Me-vacancy disorder, since the atomic positions of vacancies and Me atoms cannot be distinguished from the X-ray powder diffraction pattern. Conventional corresponding Li3MeBr6 can have a crystal structure represented by the C2 / m space group. Briefly turning to Figure 1B for further understanding, as shown, the co-occupancy of Me atoms 130 and vacancies 140 at the crystal positions 160 is low (i.e., less than 10%).

[0091] As another example, vacancies in the crystal structure of Li3MeCl6 can be included in the formula, and the halide-based material can be represented as Li3Me· oct 2Cl6. The Li3MeCl6 of the examples herein can have a crystal structure represented by the P63 / mcm space group, and when the occupancy of the Me position is 33.33%, the crystal structure can have octahedral vacancies· oct and perfect atomic disorder at the Me positions, i.e., 100% Me-vacancy disorder based on the powder XRD pattern, where the atomic positions of vacancies and Me atoms are indistinguishable.

[0092] As mentioned in the examples herein, the halide-based material can have multiple phases. Atomic disorder can be determined taking into account the phase concentrations. For example, the halide-based material can include a first crystal phase and a second crystal phase. The first crystal phase has a crystal structure represented by a first space group different from the corresponding conventional halide-based material and a% atomic disorder, where the first crystal phase can have a concentration of b wt%, and the second crystal phase has a crystal structure represented by a second space group and c% atomic disorder, where the second phase has a concentration of d wt%. The second space group can be the same as or different from the corresponding conventional halide-based material. The halide-based material can have atomic disorder as a linear overall disorder. D LT is determined by the formula D LT = a% * b% + c% * d%. For further understanding, in one example, the first phase can have a concentration of 90% and an atomic disorder of 96%, and the second phase can have a concentration of 10 wt% and an atomic disorder of 6%. The atomic disorder of the halide-based material is D LT = 90% * 96% + 10% * 6% = 87%.

[0093] In another embodiment, the halide-based material can include a crystal structure that includes crystal sites occupied by both Me atoms and vacancies. In one aspect, the multiplicity of the crystal sites can be 3. In another aspect, the crystal sites can be Wycoff positions 3a or 3b.

[0094] In another embodiment, the halide-based material can include a crystal structure that includes crystal sites occupied by both Me and M atoms. In one aspect, atomic disorder can include co-occupation of atomic sites by Y and Li. In a particular aspect, at least 5%, at least 10%, or at least 20% of the Y atoms can co-occupy Li sites. In another particular aspect, at most 50%, at most 70%, or at most 90% of the Y atoms can co-occupy Li sites. In another particular aspect, the Y atoms present at the Li sites can be caused by some Y atoms migrating from one layer to another in the crystal structure. Such atomic disorder can result in a decrease in the intensity of the first XRD peak of the halide-based material, such as a slight decrease.

[0095] In a particular embodiment, compared to a corresponding conventional halide-based material, the X-ray diffraction pattern of the halide-based material measured with Cu K-α radiation can include no peaks between 16° and 25° 2-θ. A particular example of such a halide-based material can have a chemical composition including Li, Y, and Br (hereinafter referred to as "LYB"). In a particular aspect, the X-ray diffraction pattern can include no multiple peaks between 16° and 25° 2-θ. In another particular aspect, the X-ray diffraction pattern can be substantially free of peaks between 16° and 25° 2-θ.

[0096] It should be understood that the halide-based material can include an XRD pattern that includes no peaks at a specific range of 2-θ, where this range can change when the chemical composition changes. In one embodiment, Me can be partially replaced by another Me metal, and the change in the 2-θ range can be negatively correlated with the change in the lattice parameter caused by the partial replacement. For example, due to the partial replacement of Y with another Me ion having a larger size, the lattice parameter of the LYB material mentioned in the above embodiment can increase by 5%, and there can be no XRD peaks between 15.2° and 23.75° 2-θ. In another example, due to the partial replacement of Y with another Me ion having a smaller size, the lattice parameter of the LYB material can decrease by 7%, and there can be no XRD peaks between 17.12° and 26.75° 2-θ. The lattice parameters that can be affected by the partial replacement of Me can include A, C, B, or any combination thereof. In some instances, A and C may be affected equally. In another instance, A and C may be affected slightly differently.

[0097] See Figures 1A to 1C , the crystal structure represented by R-3m includes disordered Me and vacancy positions, as Figure 1A shown. The octahedral position 160 is occupied by Me atoms 130 and vacancies 140. As shown, 1 / 3 of the octahedra 160 are occupied by Me and 2 / 3 are vacant. This configuration represents a relatively high degree of Me-vacancy disorder. Compared with Figure 1B the conventional C2 / m shown, one Me atom 130 and two vacancies 140 are ordered because the atomic positions 160 are nearly empty or nearly full, thus forming a regular or ordered pattern within the empty / vacant (unfilled spheres) and full / occupied (partially filled spheres) positions. This configuration represents low Me-vacancy disorder (i.e., less than 10%). In Figure 1C , the C2 / m space group unit cell shown has a smaller volume than the conventional unit cell shown in Figure 1B , and the Me atoms and vacancies occupy the same positions, i.e., 1 / 3 and 2 / 3 of the same positions respectively. This configuration also represents a relatively high degree of Me-vacancy disorder.

[0098] Figure 6A and 6B respectively include the spectra of X-ray powder diffraction simulations of lithium yttrium bromide with the crystal structures shown in Figure 1A and 1B . Compared with the spectrum of Figure 6B , the spectrum shown in Figure 6A indicates the absence of peaks at 16° to 25° 2-θ, which corresponds to the completely disordered Y and vacancy positions in the crystal structure of R-3m. Similarly, compared with the spectrum of Figure 6B , the spectrum shown in Figure 6C indicates the absence of peaks at 16° to 25° 2-θ, which corresponds to the completely disordered Y and vacancy positions in the crystal structure represented by the C2 / m space group, which has a unit cell approximately 3 times smaller than the conventional monoclinic unit cell.

[0099] Figures 7A to 7E includes the spectrum of X-ray diffraction simulation of a halide-based material that includes Li, Y, and Cl with different crystal structures. Figure 7A includes the simulated spectrum of a halide-based material with a crystal structure represented by Pnma (as shown in Figure 2A ), and Figure 7B includes the simulated spectrum of a halide-based material with a crystal structure represented by P-3m1 (as shown in Figure 2B ). Figure 7C includes the simulated spectrum of a halide-based material with a crystal structure represented by the space group P63 / mcm (as shown in Figure 2C ). Turning toFigures 2A to 2C , by Pnma( Figure 2A ) or P-3m1( Figure 2B ) shows that the Y and vacancy positions are ordered, while P63 / mcm( Figure 2C ) includes a linear disorder of Y 210 and vacancy 220 positions. The atomic order of the crystal structures 200 and 201 is indicated by the alternating and regular ordered appearance of Y 210 and vacancies 220 in a linear chain including octahedra. Figure 2C The atomic disorder in is shown by a complete mixture of 50% Y 210 and 50% vacancies 220 in a linear chain 230 of octahedra. Figure 7A and Figure 7B In contrast, linear disorder is caused by Figure 7C This is indicated by the absence of a peak between 16.5° and 27.5° 2-theta.

[0100] Figure 7D Included are simulated spectra of halide-based materials having a crystalline structural disorder including migration of a portion of Y into the Li channel. In one example, at least 5%, at least 10%, or at least 20% of the Y atoms may migrate into the Li channel. Figure 7E Simulated spectra of halide-based materials including the crystalline structure of P63 / mmc. Figure 2D As shown, Figure 2A and 2B By further comparison, the crystalline structure 203 of P63 / mmc includes complete Y intermixing with Li atoms, as shown at 240. In one specific example, the halide-based material may be lithium yttrium chloride, and the crystalline structure disorder may include complete intermixing of Y and Li sites. Figure 7A and 7B Compared to the spectra shown, Figures 7C to 7E The spectrum in the range includes the absence of one or more peaks from 16.5° to 27.5° 2-θ. In particular, the XRD pattern may include a first XRD peak around 15.5° 2-θ with reduced intensity or complete absence.

[0101] It is noteworthy that the halide-based materials of the embodiments herein may have one or more crystalline structure disorder and specific crystallinity characteristics mentioned in the embodiments herein, including average diffraction grain size, microstrain, corrected average FWHM, crystal density, or any combination thereof. The one or more disorder, one or more specific crystallinity characteristics, or any combination thereof may be beneficial to improve the properties of solid electrolyte materials. Such properties may include ionic conductivity, mechanical properties (such as but not limited to plasticity, compliance, consistency, flexibility), electrochemical stability, chemical stability, thermal stability, resistivity, particle morphology and / or size, electrode wettability, etc., or any combination thereof.

[0102] In another embodiment, the solid electrolyte material may comprise a halide-based material having a specific average diffraction grain size. The average diffraction grain size may also be referred to as the coherent X-ray scattering domain size and is determined using X-ray diffraction analysis of the halide-based material and the Scherrer equation L = (Kλ) / (β cos θ), where L represents the average diffraction grain size, where K is a dimensionless shape factor with a value close to one and a typical value of 0.9 to 1; λ is the X-ray wavelength; β is the line broadening (FWHM) at half the maximum intensity after subtracting the instrumental line broadening, in radians; and θ is the Bragg angle.

[0103] In one aspect, the average diffraction grain size can be at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm, or at least 40 nm. In another aspect, the average diffraction grain size can be at most 500 nm, at most 400 nm, at most 300 nm, at most 200 nm, or at most 100 nm. In yet another aspect, the average diffraction grain size can be in a range including any of the minimum and maximum values mentioned herein.

[0104] In yet another embodiment, the halide-based material may comprise microstrain. The microstrain ∈ is a dimensionless parameter detected by X-ray diffraction analysis β = 4∈ tan θ. In one aspect, the microstrain can be at most 1%, at most 0.6%, at most 0.35%, at most 0.2%, or at most 0.1%. In another aspect, the microstrain may be absent. In yet another aspect, the microstrain can be at least 0.005%, such as at least 0.05%, at least 0.08%, at least 0.1%, or at least 0.2%. Additionally, the halide-based material may comprise microstrain in a range including any of the minimum and maximum percentages mentioned herein.

[0105] In yet another embodiment, the halide-based material can include a corrected FWHM (referred to as "corrected average FWHM") averaged over a diffraction angle 2-θ range of 10° to 80°. The corrected average FWHM is intended to refer to the average FWHM corrected for instrumental broadening. The instrumental broadening can be determined by recording the X-ray diffraction pattern of a highly crystalline standard commercial material LaB6 (supplier: NIST) under the same measurement conditions (geometry, slits, detector, or other hardware and optical parameters of the diffractometer) as the halide-based material to be tested. The peak broadening of the standard material is subtracted from the peak broadening of the halide-based material to obtain the corrected FWHM as a function of the diffraction angle 2-θ. In one aspect, the corrected average FWHM can be less than 1.5%, at most 1.4%, at most 1.2%, at most 1%, at most 0.8%, or at most 0.5%. In another aspect, the halide-based material can include at least 0.5%, at least 0.8%, or at least 1% of the corrected average FWHM. Additionally, the corrected average FWHM can be within a range including any of the minimum and maximum percentages mentioned herein.

[0106] In one embodiment, the halide-based electrolyte material can include a specific crystallographic density determined by X-ray diffraction analysis. The crystallographic density is the density of the unit cell, which is given as the ratio of the mass of the unit cell to its volume. The mass of the unit cell is equal to the product of the number of atoms in the unit cell and the mass of each atom in the unit cell. In one aspect, the halide-based material can have a crystallographic density of at least 95% and up to 100% of the theoretical crystallographic density. In another aspect, the halide-based electrolyte material can include a crystallographic density in the range of 2.0 g / cm 3 to 4.2 g / cm 3 .

[0107] In a specific embodiment, when X is Br, the halide-based electrolyte material can include a crystallographic density in the range of 3.0 g / cm 3 to 4.2 g / cm 3 or 3.4 g / cm 3 to 3.9 g / cm 3 . In another specific embodiment, when X is Cl, the halide-based electrolyte material can include a crystallographic density in the range of 2.0 g / cm 3 to 3.2 g / cm 3 or 2.2 g / cm 3 to 2.8 g / cm 3 .

[0108] Figure 8Illustration of process 800 for forming a solid electrolyte material including a halide-based material. Process 800 may include forming (NH4) at block 802 n Me k+ X n+k 。In an exemplary embodiment, process 800 may include forming a reaction mixture comprising starting materials including ammonium halide, NH4X, one or more M metal compounds, one or more M metal compounds, or any combination thereof. In a particular embodiment, the metal compound may be non-hygroscopic. The metal compound may be in the form of an oxide, carbonate, sulfide, sulfate, hydrate, hydroxide, oxalate, acetate, nitrate, or any combination thereof. In a particular instance, the starting materials may include Me2O k 。In a more particular example, the starting materials may include one or more of the following: rare earth oxides or hydroxides or carbonates, ZrO2 or Zr(OH)4 or Zr(CO3)2 or Zr(OH)2CO3·ZrO2, or any combination thereof.

[0109] In another example, the M metal compound may include carbonates such as lithium carbonate, sodium carbonate, cesium carbonate, or combinations thereof.

[0110] The starting materials may further include an acid to facilitate acidic synthesis in water, alcohol, or other polar molecular liquid solutions.

[0111] In one instance, the metal compound may consist of M metal compounds. Exemplary M metal compounds may include halides (e.g., NaCl, CsCl, and LiCl).

[0112] The starting materials may be mixed in stoichiometric ratios or mixed to allow the formation of non-stoichiometric halide-based materials.

[0113] In a particular exemplary embodiment, a reaction mixture may be formed including NH4X, one or more rare earth metal oxides (hereinafter referred to as "RE2O3"), lithium carbonate, and hydrochloric acid or hydrobromic acid.

[0114] In an exemplary embodiment, process 800 may include reacting between the starting materials. An exemplary reaction is shown below, referring to the starting materials and reaction products in an aqueous solution.

[0115] 3*Li2CO3 + RE2O3 + 12*HX + 6*NH4X ---> 2*(NH4)3REX6 + 3*LiX + 6*H2O + 3*CO2

[0116] In view of the present application, those skilled in the art understand that different alkali metal compounds, such as Na2CO3 or NaCl, can be used to replace or supplement Li2CO3, or to replace RE2O3. Similarly, oxides of non-rare earth elements, such as MgO or ZrO2, can be added to the reaction. Those skilled in the art further understand that as the starting materials change, the reaction products can change accordingly.

[0117] In one exemplary embodiment, process 800 can include chemically substituting the water (i.e., water) in the hydrated salt MeX with NH4X. k Using the above reaction as an example, hydrated rare earth halides can be formed as intermediate products, and the water in the hydrates can be replaced by NH4X to form (NH4)3REX6. As further shown in the figure, the reaction product mixture includes alkali metal halides, such as LiX.

[0118] In one embodiment, process 800 can include forming a mixture including (NH4) n Me k+ X n+k and LiX. In a particular aspect, process 800 can include forming a homogeneous mixture including (NH4) n Me k+ X n+k and LiX.

[0119] In one instance, the reaction product mixture can be filtered to remove larger particles to facilitate subsequent solid-state reactions. The larger particles can include impurities that come with any starting materials, remaining particles of the starting materials, carbon, or any combination thereof.

[0120] Method 800 can proceed to the step of block 804. In one exemplary embodiment, the mixture of reaction products can be dried to facilitate the solid-state reaction of (NH4) n Me k+ X n+k and the alkali metal halide MX. The drying can be performed in air or dry air and / or under vacuum or reduced pressure (such as 100 mbar, 40 mbar, 1 mbar, or even 0.01 mbar). In some instances, an N2 or Ar flow can be used to facilitate the removal of water. In another example, heat can be applied to assist in the evaporation of water. The heating temperature can be from 100 °C to 160 °C. The drying can be carried out until a trace amount of water, such as 1 wt% to 3 wt%, remains in the mixture.

[0121] In one exemplary embodiment, process 800 can include performing (NH4) n Me k+ X n+kSolid-state reaction with MX. In a specific example, using the above reaction product to continue the reaction, the solid-state reaction of (NH4)3REX6 and LiX can be carried out to form (NH4) n M 3-z Me k+ X 3+n+k-z. In yet another example, process 100 may include forming (NH4) n M 3-z (Me k+ ) f X 3+n-z+k*f 。

[0122] Process 800 may proceed to block 806 to form M 3-z (Me k+ ) f X 3-z+k*f 。In an exemplary embodiment, process 800 may include decomposing ammonium halide. In an exemplary embodiment, the solid solution may be heated to a temperature in the range of at least 150 °C to at most 800 °C to allow the ammonium halide to sublime. The heating temperature may be selected based on the composition of the halide-based material. For example, for a relatively volatile halide-based material, the heating temperature may be relatively low. In another example, the heating temperature may be at least 150 °C lower than the melting temperature and / or at most 50 °C higher than the melting temperature. The heating may be carried out in a crucible made of a material inert to the reactants and products. For example, the crucible may be made of quartz, alumina, silica-alumina, BN, glassy carbon, or graphite. In a particular embodiment, the graphite may have a pyrolytic carbon coating. The heating may be carried out in a dry and neutral atmosphere such as air or dry air. An inert gas such as N2 or Ar may be used to facilitate the process. The heating may be carried out for at least 15 minutes to at most 12 hours.

[0123] In an exemplary embodiment, the sublimation of NH4X may be monitored by collecting and weighing the evolved NH4X. In a specific example, the sublimation may be complete such that the halide-based material may be substantially free of NH4X. In another specific example, a certain amount of NH4X may remain in the halide-based material.

[0124] In an exemplary embodiment, after the decomposition of NH4X, cooling may be carried out. For example, the cooling may be carried out in an air, dry air, or nitrogen atmosphere. In another example, the cooling temperature may be below 200 °C, such as at most 100 °C, at most 70 °C, at most 50 °C, or at most 30 °C or at room temperature (e.g., 20 °C to 25 °C). Optionally, Ar or N2 may be used to facilitate the cooling.

[0125] In one embodiment, cooling can be performed at a specific cooling rate, which can be beneficial for forming a halide-based material. In one example, the cooling rate can be from 10 °C / min to 100 °C / min.

[0126] It should be noted that for the formation of halide-based materials that include a relatively high content of stacking faults, the temperature cycle should be carefully controlled. For example, non-monotonic cooling or unintentional annealing may result in a decrease in the content of stacking faults. Unintentional annealing can be annealing at a temperature below 0.7Tm, where Tm is the melting point of the halide-based material in Kelvin, for a duration exceeding 10 minutes.

[0127] It should also be noted that care should be taken to control the amount of oxygen-containing substances (e.g., oxides, hydroxides, and / or moisture) that may be present during the formation of the halide-based material. Excessive oxygen-containing substances may lead to the formation of impurity phases, which may reduce certain properties of the battery components formed using the halide-based material, such as ionic conductivity. For example, a solid-state reaction or a melting reaction can be performed in a neutral atmosphere with a limited moisture content or oxygen level below 10 ppm. In another example, the initial amount of a halogenated compound (such as an acid or an ammonium halide) can be higher than the stoichiometry based on the theoretical chemical equilibrium equation (such as at least 10% more) to ensure the yield of the composite halide material and reduce the level of oxygen-containing phases derived from the metal oxide or metal carbonate raw materials to a level below that detectable by XRD.

[0128] In another embodiment, the halide-based material can include improved ionic conductivity. The ionic conductivity can be measured at room temperature (i.e., 20 °C to 25 °C). In one aspect, the ionic conductivity can be at least 0.001 mS / cm, at least 0.01 mS / cm, at least 0.1 mS / cm, at least 0.4 mS / cm, at least 0.8 mS / cm, at least 1.2 mS / cm, at least 1.8 mS / cm, or at least 2.2 mS / cm. In another aspect, the ionic conductivity can be at most 15 mS / cm, at most 13 mS / cm, at most 11 mS / cm, 8 mS / cm, at most 7.2 mS / cm, or at most 6.2 mS / cm. Additionally, the solid electrolyte can include a halide-based material having an ionic conductivity within a range including any of the minimum and maximum values mentioned herein. In one embodiment, the ionic conductivity can be predominantly bulk ionic conductivity.

[0129] In one embodiment, compared with a corresponding conventional halide-based material, the halide-based material may include improved purity. The corresponding conventional halide-based material is intended to refer to a halide-based material that may be represented by the same formula as the halide-based materials mentioned in the embodiments herein, but is formed by a process different from the processes described in the embodiments herein. In one embodiment, the halide-based material may include a certain content of impurities. For example, the impurities may include by-products formed by the process of forming the halide-based material, or any combination thereof. The impurities may exist as a phase different from the composite compound of the halide-based material. Those skilled in the art will understand that when the impurities are present at a relatively high content (i.e., at least 0.3 wt%), the impurity phase can be detected by X-ray diffraction analysis of the halide-based material. For example, characteristic peaks of the impurity phase may be present in the spectrum of the halide-based material. In yet another example, the impurities may include binary halides (e.g., LiCl, LiBr, YCl3, and / or YBr3), oxohalides (e.g., YOCl and / or YOBr), nitrides, or any combination thereof.

[0130] In one embodiment, the halide-based material may include a specific total content of all impurities, which may be beneficial to improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of all impurities may constitute at most 15 wt% of the weight of the halide-based material of the embodiments herein. For example, the total content of impurities may account for at most 14 wt% of the weight of the composite metal halide, such as at most 13 wt%, at most 12 wt%, at most 11 wt%, at most 10 wt%, at most 9 wt%, at most 8 wt%, at most 7 wt%, at most 6 wt%, at most 5 wt%, at most 4 wt%, at most 3 wt%, at most 2 wt%, at most 1 wt%, at most 0.5 wt%, at most 0.3 wt%, at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm. In another aspect, the halide-based material may include a total content of impurities that is at least 0.2 ppm of the weight of the halide-based material, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm. In another aspect, the total content of impurities may be within a range including any of the minimum or maximum values mentioned herein.

[0131] The content of the impurity phase can be determined by XRD analysis linked to Rietveld refinement for quantitative analysis through the presence of characteristic diffraction peaks corresponding to the parasitic phase. Rietveld refinement (RR) can analyze the shape and position of the peaks in the XRD pattern to quantitatively identify the contribution of each phase by collecting 2θ data at small increments of the 2θ angle in the XRD diffraction and converting the XRD data into the ratios of different phases.

[0132] For nitride-based impurity phases, LECO analysis can also be used to determine the presence and quantify the phase, especially when the nitride-based impurity phase is present in a molar or mass amount below 0.1%. LECO analysis is based on the following: combustion of the sample and analysis of the presence of nitrogen (or sulfur, carbon, hydrogen, oxygen) through the thermal conductivity of the boiling material gas or the infrared absorption pattern.

[0133] In certain embodiments, the halide-based material can include a low level of impurity phase where the impurity phase cannot be detected by powder XRD analysis. For example, in the spectrum of the halide-based material, the characteristic peaks of the impurity phase may be unidentifiable. Those skilled in the art will understand that powder XRD can be performed using prior art diffractometers such as Rigaku SmartLab or Bruker D2 phaser.

[0134] In one embodiment, the impurity can include a nitride-based compound, which includes metal nitrides, metal oxynitrides, metal-carbonitrides, or any combination thereof. In yet another embodiment, the halide-based material can include a specific total content of nitride-based impurity phase, which can be beneficial for improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of the nitride-based impurity phase can be at most 0.5 wt% of the weight of the halide-based material, such as at most 0.3 wt%, at most 0.2 wt%, at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm of the weight of the complex metal halide. In another aspect, the total content of the nitride-based impurity phase can be at least 0.2 ppm of the weight of the complex metal halide, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm of the weight of the complex metal halide. In yet another aspect, the total content of the nitride-based impurity phase can be within a range including any of the minimum or maximum values mentioned herein.

[0135] In one embodiment, the halide-based material may include an impurity, which includes an alkali metal halide (MX). Specific examples of MX may include LiCl, LiBr, NaCl, CsCl, NaBr, CsBr, or any combination thereof. In another embodiment, the halide-based material may include a specific content of MX, which may be beneficial to improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of the MX phase may be at most 10 wt% of the weight of the halide-based material, such as at most 9 wt%, at most 8 wt%, at most 7 wt%, at most 6 wt%, at most 5 wt%, at most 4 wt%, at most 3 wt%, at most 2 wt%, at most 1 wt%, at most 0.5 wt%, at most 0.3 wt%, at most 0.2 wt%, at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm of the weight of the halide-based material. In another aspect, the total content of the MX phase may be at least 0.2 ppm of the weight of the halide-based material, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm of the weight of the halide-based material. In another aspect, the total content of the MX phase may be in a range including any of the minimum or maximum values mentioned herein.

[0136] In one embodiment, the halide-based material may include an impurity, which includes a metal halide oxide (MeOX). Examples of MeOX may include rare earth halide oxides. In yet another embodiment, the halide-based material may include a total content of MeOX, which may be beneficial to improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of MeOX may be at most 5 wt% of the weight of the composite metal halide, such as at most 4 wt%, at most 3 wt%, at most 2 wt%, at most 1 wt%, at most 0.5 wt%, at most 0.3 wt%, at most 0.2 wt%, at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm of the weight of the halide-based material. In another aspect, the content of the MeOX phase may be at least 0.2 ppm of the weight of the composite metal halide, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm of the weight of the halide-based material. In another aspect, the total content of the MeOX phase may be in a range including any of the minimum or maximum values mentioned herein. In a particular aspect, the halide-based material may be substantially free of MeOX.

[0137] In one embodiment, the halide-based material may include an impurity, which includes a metal nitride Mex N k 。Me x N k Examples of x N k phase can include rare earth nitrides. In yet another embodiment, the halide-based material can include a specific total content of Me x N k phase, which can be beneficial to improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of Me x N k phase can be at most 0.3 wt% of the weight of the halide-based material, such as at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm of the weight of the halide-based material. In another aspect, the content of Me x N k phase can be at least 0.2 ppm of the weight of the halide-based material, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm of the weight of the halide-based material. In another aspect, the total content of Me x N k phase can be in a range including any of the minimum or maximum values mentioned herein.

[0138] In one embodiment, the halide-based material can include an impurity, which includes metal nitride M x N. M x N. Examples of M x N can include alkali metal nitrides. In yet another embodiment, the halide-based material can include a specific total content of M x N phase, which can be beneficial to improving the properties and / or crystallization characteristics of the halide-based material. In one aspect, the total content of metal nitride M x N can be at most 0.3 wt% of the weight of the halide-based material, such as at most 0.1 wt%, at most 500 ppm, at most 300 ppm, at most 100 ppm, at most 50 ppm, at most 40 ppm, at most 30 ppm, at most 20 ppm, or at most 10 ppm of the weight of the halide-based material. In another aspect, the total content of M x N can be at least 0.2 ppm of the weight of the halide-based material, such as at least 0.5 ppm, at least 1 ppm, or at least 2 ppm of the weight of the halide-based material. In another aspect, the total content of M x N can be in a range including any of the minimum or maximum values mentioned herein.

[0139] Many different aspects and embodiments are possible. Some of those aspects and embodiments are described herein. After reading this specification, those skilled in the art will understand that those aspects and embodiments are merely illustrative and do not limit the scope of the invention. The embodiments may be based on any one or more of the embodiments listed below.

[0140] Embodiment

[0141] Embodiment 1. A solid electrolyte material, the solid electrolyte material comprising:

[0142] M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k < 6; 0 ≤ f ≤ 1; M comprises an alkali metal element; Me comprises a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X comprises a halogen; and

[0143] A crystalline structure, the crystalline structure comprising at least 20% stacking faults.

[0144] Embodiment 2. The solid electrolyte material according to Embodiment 1, wherein the crystalline structure is represented by the C2 / m space group.

[0145] Embodiment 3. A solid electrolyte material, the solid electrolyte material comprising

[0146] M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k < 6; 0 ≤ f ≤ 1; M comprises an alkali metal element; Me comprises a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X comprises a halogen; and

[0147] A crystalline structure, the crystalline structure being represented by the rhombohedral space group.

[0148] Embodiment 4. The solid electrolyte material according to Embodiment 3, the solid electrolyte material comprising a crystalline phase, the crystalline phase comprising a crystalline structure represented by the R-3m space group.

[0149] Embodiment 5. The solid electrolyte material according to any one of Embodiments 3 to 4, wherein the solid electrolyte material consists essentially of a crystalline phase comprising a crystalline structure represented by the R-3m space group.

[0150] Embodiment 6. A solid electrolyte material, the solid electrolyte material comprising:

[0151] M3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k < 6; 0 ≤ f ≤ 1; M includes alkali metal elements; Me includes divalent metal elements, trivalent metal elements, tetravalent metal elements, pentavalent metal elements, hexavalent metal elements, or any combination thereof; and X includes halogens; and

[0152] A crystal structure, which is represented by a hexagonal space group.

[0153] Example 7. The solid electrolyte according to Example 6, the solid electrolyte includes a crystalline phase, and the crystalline phase includes a crystal structure represented by the space group P63 / mcm or P63 / mmc.

[0154] Example 8. The solid electrolyte material according to Example 6 or 7, wherein the solid electrolyte material consists essentially of a crystalline phase including a crystal structure represented by the space group P63 / mcm or P63 / mmc.

[0155] Example 9. The solid electrolyte material according to Example 1, 3 or 6, the solid electrolyte material includes a crystalline phase, and the crystalline phase includes a crystal structure represented by the space group P-3m1 or Pnma.

[0156] Example 10. The solid electrolyte material according to Example 9, wherein the concentration of the crystalline phase including a crystal structure represented by the space group P-3m1 or Pnma is at most 70 wt%, at most 50 wt%, at most 25 wt%, at most 15 wt%, at most 8 wt% or at most 5 wt%.

[0157] Example 11. The solid electrolyte material according to Example 9 or 10, wherein the concentration of the crystalline phase including a crystal structure represented by the space group P-3m1 or Pnma is at least 1 wt%, at least 4 wt%, at least 10 wt%, at least 25 wt%, at least 50 wt% or at least 70 wt%.

[0158] Example 12. A solid electrolyte material, the solid electrolyte material includes:

[0159] M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k < 6; 0 ≤ f ≤ 1; M includes alkali metal elements; Me includes divalent metal elements, trivalent metal elements, tetravalent metal elements, pentavalent metal elements, hexavalent metal elements, or any combination thereof; and X includes halogens; and

[0160] A crystalline structure represented by the monoclinic space group, the monoclinic space group having a unit cell containing between 3 and 5 halogen atoms.

[0161] Example 13. The solid electrolyte material according to any one of Examples 1, 3, 6, and 12, the solid electrolyte material including a crystalline phase including a crystalline structure represented by the C2 / m space group.

[0162] Example 14. The solid electrolyte material according to Example 13, wherein the concentration of the crystalline phase including the crystalline structure represented by the C2 / m space group is at most 70 wt%, at most 50 wt%, at most 25 wt%, at most 15 wt%, at most 8 wt%, or at most 5 wt%.

[0163] Example 15. The solid electrolyte material according to Example 13 or 14, wherein the concentration of the crystalline phase including the crystalline structure represented by the C2 / m space group is at least 1 wt%, at least 4 wt%, at least 10 wt%, at least 25 wt%, at least 50 wt%, or at least 70 wt%.

[0164] Example 16. The solid electrolyte material according to any one of Examples 1 to 15, the solid electrolyte material including a layered atomic arrangement.

[0165] Example 17. The solid electrolyte material according to any one of Examples 3 to 8, wherein A represents the value of the unit cell parameter a, and B represents the value of the unit cell parameter b, and wherein A = B.

[0166] Example 18. The solid electrolyte material according to any one of Examples 3 to 5 and 17, wherein A represents the value of the unit cell parameter a, and B represents the value of the unit cell parameter b, wherein A or B or both are at least 3.0 Å, or at least 3.3 Å, or at least 3.6 Å, or at least 3.9 Å.

[0167] Example 19. The solid electrolyte material according to Examples 3 to 5, 17, and 18, wherein A or B or both are at most 4.8 Å, or at most 4.6 Å, or at most 4.3 Å, or at most 4.2 Å, or at most 4.0 Å.

[0168] Example 20. The solid electrolyte material according to any one of Examples 3 to 5 and 17 to 19, wherein C represents the value of the unit cell parameter c, wherein C is at least 17 Å, at least 18 Å, or at least 19 Å.

[0169] Example 21. The solid electrolyte material according to any one of Examples 3 to 5 and 17 to 20, wherein C is at most 21 Å, at most 20.2 Å, or at most 19.5 Å.

[0170] Example 22. The solid electrolyte material according to any one of Examples 6 to 8, wherein A represents the value of the unit cell parameter a, and B represents the value of the unit cell parameter b, where A or B or both are at least 5.0 Å, or at least 5.5 Å, or at least 6.1 Å or at least 6.3 Å.

[0171] Example 23. The solid electrolyte material according to Examples 6 to 8 and 22, wherein A or B or both are at most 8 Å, or at most 7.5 Å, or at most 7.0 Å or at most 6.5 Å.

[0172] Example 24. The solid electrolyte material according to any one of Examples 6 to 8, 22 and 23, wherein C represents the value of the unit cell parameter c, where C is at least 4.8 Å, at least 5.3 Å, at least 5.7 Å or at least 6.0 Å.

[0173] Example 25. The solid electrolyte material according to any one of Examples 6 to 8 and 22 to 24, wherein C is at most 6.9 Å, at most 6.4 Å or at most 6.1 Å.

[0174] Example 26. The solid electrolyte material according to any one of Examples 3 to 8, the solid electrolyte material comprising a unit cell volume V, where V is at least 200 ų, at least 210 ų, at least 230 ų, at least 250 ų, at least 260 ų.

[0175] Example 27. The solid electrolyte material according to any one of Examples 3 to 8, the solid electrolyte material comprising a unit cell volume V, where V is at most 290 ų, at most 275 ų, at most 250 ų, at most 230 ų or at most 220 ų.

[0176] Example 28. The solid electrolyte material according to any one of Examples 1 to 27, the solid electrolyte material comprising a formula unit FU and a normalized unit cell volume V per FU N / FU , where V N / FU = V / FU, and where V N / FU is at least 200 ų, at least 210 ų, at least 230 ų or at least 250 ų.

[0177] Example 29. The solid electrolyte material according to any one of Examples 1 to 28, the solid electrolyte material comprising a formula unit FU and a normalized unit cell volume V per FU N / FU , where V N / FU = V / N FU , and N FU represents the number of formula units, and where V N / FUis at most 290 cubic angstroms, at most 275 cubic angstroms, at most 270 cubic angstroms, or at most 268 cubic angstroms.

[0178] Example 30. The solid electrolyte material according to any one of Examples 1 to 29, the solid electrolyte material comprising a normalized unit cell volume V per halogen atom N / AA , where V N / AA = V / AA, and AA represents, where V N / AA is at least 30 cubic angstroms, at least 34 cubic angstroms, at least 38 cubic angstroms, or at least 42 cubic angstroms.

[0179] Example 31. The solid electrolyte material according to any one of Examples 1 to 30, the solid electrolyte material comprising a normalized unit cell volume V per halogen atom N / AA , where V N / AA = V / AA, and AA represents, where V N / AA is at most 50 cubic angstroms, at most 46 cubic angstroms, at most 42 cubic angstroms, at most 38 cubic angstroms.

[0180] Example 32. The solid electrolyte material according to any one of Examples 1 to 31, the solid electrolyte material comprising an average diffracted grain size of at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm, or at least 40 nm.

[0181] Example 33. The solid electrolyte material according to any one of Examples 1 to 32, the solid electrolyte material comprising an average diffracted grain size of at most 500 nm, at most 400 nm, at most 300 nm, at most 200 nm, or at most 100 nm.

[0182] Example 34. The solid electrolyte material according to any one of Examples 1 to 33, the solid electrolyte material comprising a microstrain of at most 1%, at most 0.6%, at most 0.35%, at most 0.2%, or at most 0.1%.

[0183] Example 35. The solid electrolyte material according to any one of Examples 1 to 34, the solid electrolyte material comprising a corrected average FWHM of less than 1.5%, at most 1.4%, at most 1.2%, at most 1%, at most 0.8%, or at most 0.5%.

[0184] Example 36. The solid electrolyte material according to any one of Examples 1 to 35, the solid electrolyte material comprising a corrected average FWHM of at least 0.5%, at least 0.8%, or at least 1.

[0185] Example 37. The solid electrolyte material according to any one of Examples 1 to 36, the solid electrolyte material comprising at 2.0 g / cm3 to 4.2 g / cm 3 in the range of crystal density.

[0186] Example 38. The solid electrolyte material according to Example 37, wherein:

[0187] When X is Br, the solid electrolyte material includes in the range of 3.0 g / cm 3 to 4.2 g / cm 3 or in the range of 3.4 g / cm 3 to 3.9 g / cm 3 of crystal density; or

[0188] When X is Cl, the solid electrolyte material includes in the range of 2.0 g / cm 3 to 3.2 g / cm 3 or in the range of 2.2 g / cm 3 to 2.8 g / cm 3 of crystal density.

[0189] Example 39. The solid electrolyte material according to any one of Examples 1 to 38, wherein the crystal structure includes:

[0190] atomically disordered vacancies and Me atoms;

[0191] disordered X1 and X2 atoms, where X1 and X2 represent two different halogen atoms;

[0192] disordered vacancy positions and M atoms;

[0193] disordered M and Me atoms;

[0194] disordered M, Me and vacancy atoms; or

[0195] any combination thereof.

[0196] Example 40. The solid electrolyte material according to Example 39, wherein the atomically disordered vacancies and Me atoms are partially disordered in atomic layers or linear atomic chains.

[0197] Example 41. The solid electrolyte material according to any one of Examples 1 to 9 and 20, the solid electrolyte material includes at least 10%, at least 20%, at least 30%, at least 40%, at least 60%, at least 80% or at least 90% atomic disorder.

[0198] Example 42. The solid electrolyte material according to any one of Examples 1 to 41, wherein the crystal structure includes crystal positions occupied by both Me atoms and vacancies.

[0199] Example 43. The solid electrolyte material according to Example 42, wherein the multiplicity of the crystal position is 3.

[0200] Example 44. The solid electrolyte material according to Example 42 or 43, wherein the crystal position is Wyckoff position 3a or 3b.

[0201] Example 45. The solid electrolyte material according to any one of Examples 1 to 44, wherein the X-ray diffraction pattern measured with Cu K-α radiation includes no peak between 16° and 25° 2-θ.

[0202] Example 46. The solid electrolyte material according to any one of Examples 1 to 45, wherein M includes at least one of Li or Na.

[0203] Example 47. The solid electrolyte material according to any one of Examples 1 to 46, wherein M includes Li.

[0204] Example 48. The solid electrolyte material according to any one of Examples 1 to 47, wherein Me includes an alkaline earth metal element, a 3d transition metal, Mg, Ca, Ba, Zn, Zr, Hf, Ti, Sn, Th, Ge, V, Ta, Nb, Mo, W, Sb, In, Bi, Al, Ga, or any combination thereof.

[0205] Example 49. The solid electrolyte material according to any one of Examples 1 to 48, wherein Me includes a rare earth element, Zr, Sn, or any combination thereof.

[0206] Example 50. The solid electrolyte material according to any one of Examples 1 to 49, wherein Me includes Y, Ce, Gd, Er, Zr, La, Yb, In, Mg, Zn, Sn, or any combination thereof.

[0207] Example 51. The solid electrolyte material according to any one of Examples 1 to 50, wherein M includes Y.

[0208] Example 52. The solid electrolyte material according to any one of Examples 1 to 51, wherein X includes F, Cl, Br, I, or any combination thereof.

[0209] Example 53. The solid electrolyte material according to any one of Examples 1 to 52, wherein X includes Cl, Br, or a combination thereof.

[0210] Example 54. The solid electrolyte material according to any one of Examples 1 to 53, wherein X includes Br.

[0211] Example 55. The solid electrolyte material according to any one of Examples 1 to 54, wherein the solid electrolyte material is composed of Li, Y, Cl, and Br.

[0212] Example 56. The solid electrolyte material according to any one of Examples 1 to 55, wherein the crystal structure comprises at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% stacking faults.

[0213] Example 57. The solid electrolyte material according to any one of Examples 1 to 56, wherein the solid electrolyte material comprises an ionic conductivity of at least 0.001 mS / cm, at least 0.01 mS / cm, at least 0.1 mS / cm, at least 0.4 mS / cm, at least 0.8 mS / cm, at least 1.2 mS / cm, at least 1.8 mS / cm, or at least 2.2 mS / cm.

[0214] Example 58. The solid ion-conductive material according to any one of Examples 1 to 38, wherein the solid ion-conductive material comprises an ionic conductivity of at most 15 mS / cm, at most 13 mS / cm, at most 11 mS / cm, 8 mS / cm, at most 7.2 mS / cm, or at most 6.2 mS / cm.

[0215] Example

[0216] Example 1

[0217] The process described in the examples herein was used to form a representative lithium yttrium bromide sample (Li3YBr6). The decomposition of NH4Br was carried out at 400 °C to 600 °C. The sample was further ground in an automatic agate mortar-pestle to obtain finer powder particles. High-energy ball milling was not used. The crystal structure and crystallinity characteristics of the finally formed particles are included in Table 1 below.

[0218] Table 1

[0219]

[0220] Example 2

[0221] The process described in the examples herein was used to form a representative Li3YBr6 sample. Figure 9 Including X-ray diffraction spectra recorded with Cu K-α radiation. Curve 910 represents the X-ray diffraction pattern of the sample and includes bars at positions where peaks of a conventional crystal structure are expected. The sample shows no peaks between 16° and 25° 2-θ.

[0222] Example 3

[0223] Use the process described in the examples herein to form a representative Li3YBr6 sample. Figure 10 Including the structural model of the sample. The lithium yttrium bromide sample has a crystal structure represented by R-3m.

[0224] Example 4

[0225] Use the process described in the examples herein to form a representative Li3YBr6 sample. Figure 11 Including the structural model of the sample. As mentioned in the figure, the sample has a crystal structure represented by the new small C2 / m space group.

[0226] Example 5

[0227] Use the process described in the examples herein to form a representative Li3YCl6 sample. Figure 12 Including the structural model of the sample. As mentioned in the figure, the sample has a crystal structure represented by the P63 / mcm space group.

[0228] Example 6

[0229] Use the process described in the examples herein to form a representative Li3YCl6 sample. Figure 13 Including the structural model of the sample. As mentioned in the figure, the sample has a crystal structure represented by the P63 / mmc space group.

[0230] Example 7

[0231] Use the process described in the examples herein to form lithium yttrium bromide Li3YBr6. The decomposition of NH4Br is carried out at 450 °C to 650 °C. The crystal structure and crystallinity characteristics are included in Table 2 below.

[0232] Table 2

[0233]

[0234] Comparing Sample 7-1 with Samples 1-1 to 1-3, it can be noted that increasing the decomposition temperature can contribute to increasing the crystallinity, as shown by the increase in the average grain size in Example 7 compared to Example 1.

[0235] Example 8

[0236] A representative lithium yttrium bromide Li3YBr6 sample is formed in the same manner as described in Example 1, except that after grinding in an automatic agate mortar-pestle, it is additionally high-energy ball-milled at a speed of 400 rpm for 2 hours in a planetary ball mill to obtain ultrafine powder. The crystal structure and crystallinity characteristics of the finally formed particles are included in Table 3 below.

[0237] Table 3

[0238]

[0239] Example 9

[0240] A representative lithium yttrium bromide Li3YBr6 sample 10-1 was formed by the process described in the examples herein. The process includes a liquid acid reaction in addition to ammonium complexation. An additional lithium yttrium bromide Li3YBr6 sample 10-2 was formed by performing a direct solid-state reaction of LiBr and YBr3 at 450 °C for 24 hours.

[0241] Figure 14A Including the powder X-ray diffraction pattern of sample 10-1 and a comparative overlay XRD scan of conventional Li3YBr6. Figure 14B Including the X-ray diffraction pattern of sample 10-2 and a comparative overlay XRD scan of conventional Li3YBr6. It can be noted that, compared to the overlay XRD scans of conventional Li3YBr6 and sample 10-2, sample 10-1 does not include peaks within the range of 16 degrees to 25 degrees (2-θ Cu-K-α). Sample 10-1 includes approximately 83% + / - 5% stacking faults, while sample 10-2 includes approximately 15% + / - 5% stacking faults. As described in the examples herein, the FAULTS software published in 2020 was used to perform the quantification of the stacking fault values.

[0242] The crystal structure and crystallinity characteristics of sample 10-2 are further included in Table 4 below.

[0243] Table 4

[0244]

[0245] Example 10

[0246] Additional samples were formed using the synthesis methods mentioned in Table 5 below. The content of impurities in the binary metal halides is included in Table 1, and the phase of each impurity was detected by XRD analysis linked to Rietveld refinement for quantitative analysis through the presence of characteristic diffraction peaks corresponding to parasitic phases. At room temperature (approximately 22 °C), the ionic conductivity of the samples was determined using electrochemical impedance spectroscopy with gold blocking electrodes under the conditions of an alternating current frequency of 3 MHz to 10 Hz and a peak-to-peak sinusoidal alternating current voltage signal of 10 mV to 50 mV. The ionic conductivity mentioned herein is the bulk ionic conductivity, which is the conductivity contribution from the bulk grains that can be separated from the grain boundaries and electrode junctions, because the bulk grain conductivity characteristics appear at the highest frequencies and are associated with the lowest values of the double-layer capacitance.

[0247] Table 5

[0248]

[0249]

[0250] It should be noted that high-energy ball milling synthesis can parallelly generate the synthesis reaction and decomposition reaction of the main complex metal halide phase. Compared with the process of the examples in this article, high-energy ball milling synthesis can generate significantly higher contents of simple compounds, such as LiX and YX3, which exist as impurities near the main Li3YX6 phase. A higher content of impurity phases will reduce the crystallinity of the halide-based material. In some instances, annealing can be performed to partially restore the crystallinity, but annealing can also significantly reduce the stacking faults of the halide-based material.

[0251] It should also be noted that when starting from an oxide (Y2O3) or carbonate material (Li2CO3) in a solid-state reaction at 1 bar atmospheric pressure and adding ammonium halide, it may not be possible to synthesize a single phase of Li3YX6. At least two chemical reactions can occur for converting a rare earth metal (e.g., Y in the example of Li3YX6) into a halide compound. One main reaction may result in the synthesis of YX3, which can further react to form the Li3YX6 phase. The second reaction can result in the formation of YOX. YOX is a stable compound and an impurity in the final product Li3YX6. The formation of a high-level rare earth oxyhalide phase (i.e., at least 6 wt%) in the halide-based material may result in additional XRD peaks characteristic of the impurity phase, and the quantification of stacking faults based on the XRD spectrum may not be reliable.

[0252] Example 11

[0253] Additional representative halide-based materials are formed in the same manner as described with respect to Sample 10-1 in Example 9. The formula of each sample is as mentioned in Table 6. The stacking fault content of each sample in the samples is determined in the same manner as described in Example 9. Each sample is expected to have a stacking fault of 30% to 85%.

[0254] Table 6

[0255] Sample Composition 11-1 <![CDATA[Li3In 0.5 Y 0.5 Cl6]]> 11-2 <![CDATA[Li 2.7 Y 0.7 Sn 0.3 Cl6]]> 11-3 <![CDATA[Li 2.65 Y 0.65 Zr 0.35 Cl6]]> 11-4 <![CDATA[Li 2.6 Na 0.05 Y 0.65 Zr 0.35 Cl6]]> 11-5 <![CDATA[Li 2.95 Na 0.05 YBr6]]> 11-6 <![CDATA[Li3YBr3Cl3]]>

[0256] Figure 15 Including the XRD spectrum of Sample 11-6 and a comparative overlay XRD scan for conventional Li3YBr6. It can be noted that compared with the XRD scan of conventional Li3YBr3, some peaks between 15° and 25° 2-θ under Cu K-α radiation are absent in the spectrum of Sample 11-6.

[0257] Example 12

[0258] The powder XRD measurements of Sample 10-1 are performed in a sealed Kapton capillary in transmission geometry and a conventional powder sample holder, respectively. Figure 16Including the superposition of XRD spectra from the tests. It can be noted that, compared to the positions of the bars representing the XRD peaks of conventional Li3YBr3, both spectra indicate the absence of certain peaks between 15° and 25° 2-θ under Cu K-α radiation.

[0259] Example 13

[0260] Use the process described in the examples herein to form lithium yttrium bromide Li3YBr6. Decompose NH4Br. Heat the reaction mixture to 650 °C within 30 minutes and hold for 15 min for the decomposition of NH4Br, then cool to room temperature within 1 h. Rapid cooling from a higher temperature can promote the formation of stacking faults. The content of stacking faults in the sample is estimated to be approximately 50%.

[0261] Example 14

[0262] Use the process described in the examples herein to form lithium yttrium bromide Li3YBr6. Decompose NH4Br at 350 °C to 440 °C for at least 1.5 h before cooling. The content of stacking faults in the sample is expected to be 10% to 20%.

[0263] The benefits, other advantages, and solutions to problems have been described above with reference to specific embodiments. However, the benefits, advantages, solutions to problems, and any features that may cause any benefit, advantage, or solution to be conceived or become more prominent are not considered to be key, required, or essential features of any or all of the claims. Materials mentioned herein that include one or more components may be interpreted to include at least one embodiment in which the material consists essentially of the specified one or more components. The term "consisting essentially of" shall be interpreted to include the components that include the specified materials and exclude all other materials except for minor amounts (e.g., impurity content) of materials that do not significantly alter the properties of the material. In addition or alternatively, in certain non-limiting embodiments, any of the compositions specified herein may be substantially free of materials not explicitly disclosed. The examples herein include ranges of the content of certain components within a material, and it should be understood that the total content of the components within a given material is 100%.

[0264] The description and illustrations of the embodiments described herein are intended to provide a general understanding of the structures of the various embodiments. The description and illustrations are not intended to be an exhaustive and comprehensive description of all elements and features of the devices and systems that use the structures or methods described herein. Separate embodiments may also be provided in a combined manner in a single embodiment, and conversely, the various features described in the context of a single embodiment for the sake of brevity may also be provided separately or in any sub-combination. Further, references to values expressed as ranges include each and every value within that range. Many other embodiments will be apparent to those skilled in the art only after reading this specification. Other embodiments can be utilized and obtained through the present disclosure, such that structural substitutions, logical substitutions, or other changes can be made without departing from the scope of the present disclosure. Accordingly, the present disclosure should be regarded as illustrative rather than restrictive.

Claims

1. A solid electrolyte material, the solid electrolyte material comprising: M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k ≤ 6; 0 < f ≤ 1; M includes an alkali metal element; Me includes a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X includes a halogen; A crystalline structure, the crystalline structure comprising at least 20% stacking faults and an average diffraction grain size of at least 25 nm.

2. The solid electrolyte material according to claim 1, wherein the crystalline structure is represented by the C2 / m space group.

3. The solid electrolyte material according to claim 1, wherein the crystalline structure comprises at least 50% stacking faults.

4. The solid electrolyte material according to claim 1, wherein the X-ray diffraction pattern measured with Cu K-α radiation has no peak between 16° and 25° 2-θ.

5. The solid electrolyte material according to claim 1, wherein M comprises at least one of Li or Na.

6. The solid electrolyte material according to claim 1, wherein Me comprises a rare earth element, Zr, Sn, or any combination thereof.

7. The solid electrolyte material according to claim 1, wherein Me comprises Y.

8. The solid electrolyte material according to claim 1, wherein X comprises Cl, Br, or a combination thereof.

9. The solid electrolyte material according to claim 1, wherein the solid electrolyte material consists of Li, Y, Cl, and Br.

10. The solid electrolyte material according to claim 1, the solid electrolyte material comprising a crystalline phase, the crystalline phase comprising a crystalline structure represented by the P-3m1 or Pnma space group.

11. The solid electrolyte material according to claim 1, wherein the crystalline structure comprises at least 70% stacking faults.

12. A solid electrolyte material, the solid electrolyte material comprising M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k ≤ 6; 0 < f ≤ 1; M includes an alkali metal element; Me includes a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X includes a halogen; A crystalline structure having an average diffraction grain size of at least 25 nm, wherein the crystalline structure is represented by the rhombohedral space group or the hexagonal space group.

13. The solid electrolyte material according to claim 12, the solid electrolyte material comprising a crystalline phase, the crystalline phase comprising a crystalline structure represented by the R-3m space group.

14. The solid electrolyte material according to claim 12, the solid electrolyte material comprising a crystalline phase, the crystalline phase comprising a crystalline structure represented by the P63 / mcm or P63 / mmc space group.

15. The solid electrolyte material according to claim 12, wherein M comprises Li, Na, or a combination thereof, wherein Me comprises Y, Ce, Gd, Er, Zr, La, Yb, In, Mg, Zn, Sn, or any combination thereof, wherein X comprises at least one of Br and Cl.

16. The solid electrolyte material according to claim 12, wherein the crystalline structure comprises at least 90% stacking faults and an average diffraction grain size of at least 30 nm and at most 500 nm.

17. The solid electrolyte material according to claim 12, wherein the crystal structure comprises: A layered atomic arrangement; and At least one of the following: Atomically disordered vacancies and Me atoms; Disordered X1 and X2 atoms, where X1 and X2 represent two different halogen atoms; Disordered vacancy positions and M atoms; Disordered M and Me atoms; Disordered M, Me, and vacancy atoms; Or any combination thereof.

18. A solid electrolyte material, the solid electrolyte material comprising: M 3-z (Me k+ ) f X 3-z+k*f , where -3 ≤ z < 3; 2 ≤ k ≤ 6; 0 < f ≤ 1; M includes an alkali metal element; Me includes a divalent metal element, a trivalent metal element, a tetravalent metal element, a pentavalent metal element, a hexavalent metal element, or any combination thereof; and X includes a halogen; a crystalline structure having an average diffraction grain size of at least 25 nm, wherein the crystalline structure is represented by a monoclinic space group having a unit cell containing between 3 and 5 halogen atoms.

19. The solid electrolyte material according to claim 18, the solid electrolyte material comprising a crystalline phase, the crystalline phase comprising a crystalline structure represented by the C2 / m space group.

20. The solid electrolyte material according to claim 18, the solid electrolyte material comprising a layered atomic arrangement; and wherein the average diffraction grain size is at least 35 nm.

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