Solid electrolytes and methods for making the same

Abstract

In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to solid chalcohalide electrolytes and the efficient synthesis of solid chalcohalide electrolytes. The electrolytes have the general formula AaMbNcXdYeSf and have relatively high ionic conductivity. The electrolytes can be a component of different types of batteries. The process of synthesizing the electrolytes can be done with cost-effective materials, which is useful for scaling-up production of batteries such as all-solid-state batteries.

Description

SOLID ELECTROLYTES AND METHODS FOR MAKING THE SAMESTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with government support under DMR1847038, DM 1644779, and DM R2128556 awarded by the National Science Foundation. The government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to co-pending U.S. Provisional Patent Application No. 63 / 603,404, filed on November 28, 2023, the contents of which are incorporated by reference herein in their entireties.BACKGROUND

[0003] As the demand for safe, affordable, sustainable, and renewable energy continues to rise, it has become more urgent to advance existing frontiers in the development of cost-effective energy storage. With the advent of superionic solid electrolytes (SEs), all-solid-state batteries (ASSBs) have emerged as next-generation high-performance secondary batteries. Both Li- and Na-superionic SEs can satisfy cost and performance metrics necessary for consumer electronics and large-scale energy storage. Over the past decades, ternary halides, e.g., LiAICl4 (LAC) and NaAICL (NAC), have gained popularity owing to their low cost and fast ion transport when in solution or as a melt. While this class of halide electrolytes demonstrates great potential in the liquid or molten state, there remains a need to overcome numerous safety issues associated with liquid electrolytes.

[0004] One consideration in the development of SEs for practical applications is the cost of materials. Aluminum is the third most abundant element in the earth’s crust, which makes its compounds desirable in both lithium and sodium SEs for ASSBs. The stability, electrochemical performance, and structure of alkali tetrahaloaluminates ZAIX4 (Z = Li, Na; X = Cl, Br, I) has been examined in previous studies. LiAICk, for example, has a good electrochemical stability window of 1.7 V - 4.5 V vs Li / Li+. Computational predictions have suggested that doping LiAICLwith Zn may lead to some improvements in its ionic conductivity. However, the synthesis of computationally predicted materials requires a careful synthesis route which is often unachievable due to thermodynamic considerations.

[0005] In the design of promising low melting point SEs, a one-step synthesis approach that uses mechanochemistry is beneficial as it can remove the extra heating step. Despite the efforts in the past years to provide structural insights to improve the Li+dynamics within this material class, the ionic conductivity of this class of SE is still significantly low, consequently limiting the practical applications of this material.SUMMARY

[0006] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to solid chalcohalide electrolytes and the efficient synthesis of solid chalcohalide electrolytes. The electrolytes have the general formula AaMbNcXdYeSfand have relatively high ionic conductivity. The electrolytes can be a component of different types of batteries. The process of synthesizing the electrolytes can be done with cost- effective materials, which is useful for scaling-up production of batteries such as all-solid-state batteries.

[0007] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0009] FIGS. 1A-1 D show powder X-ray diffraction (XRD) pattern of as-milled LiAICU (LAC), Li4AICl3S2 (LACS2), U2AICI3S (LACS), and U2AICI3S (heat treated at 150 °C for 2 hours) with the comparison of the ICSD patterns of precursor and LiAICU monoclinic phase (P2i / C space group)(Fig. 1A) and as-milled LiAICU, Li2Alo 9Gao 1CI27Fo3S, and Li2AI09Ga02CI24F06S with the comparison of the ICSD patterns of precursor and LiAICU monoclinic phase (P2i / C space group) (Fig. 1C). Fig. 1 B and Fig. 1 D are magnified view of selected positions of Fig. 1A and Fig. 1C, respectively.

[0010] FIGS. 2A-2B show powder X-ray diffraction pattern of as-milled NaAICL (NAC) and Na2AIChS (NACS), with the comparison of the ICSD patterns of precursor and NaAICL orthorhombic phase (P2i2i2i space group) (Fig. 2A) and the magnified view of the selected position of Fig. 2A (Fig. 2B).

[0011] FIGS. 3A-3B show monoclinic structures of LiAICL with P2i / c space group obtained from the refined SXRD pattern (Fig. 3A) and Li2AICl3S with P2i / c space group obtained from the refined SXRD pattern (Fig. 3B).

[0012] FIGS. 3C-3D show synchrotron diffraction patterns and the corresponding Rietveld refinement fits of LiAICU (Fig. 3C) and Li2AIChS (Fig. 3D).

[0013] FIGS. 4A-4B show monoclinic structures of NaAICL with P2i2i2i space group obtained from the refined XRD pattern (Fig. 4A) and Na2AIChS with P2i2i2i space group obtained from the refined XRD pattern (Fig. 4B).

[0014] FIGS. 4C-4D show synchrotron diffraction patterns and the corresponding Rietveld refinement fits of NaAICL (Fig. 4C) and Na2AICl3S (Fig. 4D).

[0015] FIG. 5 shows high-resolution6Li MAS solid-state NMR spectra of LAC, LACS, and LACS2 solid electrolytes.

[0016] FIG. 6 shows high-resolution23Na MAS solid-state NMR spectra of ball-milled NaAICL, Na2AIChS, and Na2S solid electrolytes.

[0017] FIG. 7A shows Nyquist plots of LiAICU, Li2AICIsS, and Li4AICl3S2.

[0018] FIG. 7B shows an exemplary equivalent circuit fitting of the Nyquist plot at 25 °C for LACS.

[0019] FIG. 7C shows DC polarization effects of LiAICU, Li2AIChS, and Li4AIChS2.

[0020] FIG. 7D shows an Arrhenius plot and activation energy of LiAICU, LhAIChS, and U4AICI3S2.

[0021] FIG. 8A shows Nyquist plots of LhAI0.9Ga0.1Ch.7F0.3S, LhAI0.8Ga0.2Ch.4F0.6S, and LhAlo 7Gao 3Ch 1Fo9S.

[0022] FIG. 8B shows an equivalent circuit fitting of the Nyquist plot at 25 °C for Li2AI0.8Ga0.2CI2.4F0.6S.

[0001] FIG. 8C shows DC polarization effects of Li2AI09Ga01CI27F03S, Li2AI08Ga02CI24F06S, and Li2Alo.7Gao.3CI2.1Fo.9S.

[0023] FIG. 8D shows an Arrhenius plot and activation energy of Li2AI09Ga01CI27F03S, Li2AI0.8Ga0.2CI2.4F0.6S, and Li2AI0.7Ga0.3CI2.1F0.9S.

[0024] FIG. 9A shows Nyquist plots of NaAICL and Na2AICl3S.

[0025] FIG. 9B shows an exemplary equivalent circuit fitting of the Nyquist plot at 25 °C for NACS.

[0026] FIG. 9C shows DC polarization effects of NaAICL and Na2AICl3S.

[0027] FIG. 9D shows an Arrhenius plot and activation energy of NaAICL and Na2AIChS.

[0028] FIG. 10 shows lab powder XRD pattern and refinement of simultaneous Ga and F doped on LACS (Li2AI0.8Ga0.2CI2.4F0.6S).

[0029] FIG. 11 shows lab powder XRD pattern of different compositions with cation and anion substituted LAC and comparison with the precursors.

[0030] FIG. 12A shows a structure of sulfur-doped LiAICU, showing edge shared tetrahedron of sulfur and chlorine anions. Lithium and aluminum occupancy is shared in one site whereas another 4e site is fully occupied with lithium. An increase in lithium-ion conduction is possible as lithium can use the aluminum sites that are shared.

[0031] FIG. 12B shows chlorine-doped L12S structure observed as trace amount on refinement.

[0032] FIG. 13 shows representative Nyquist plots from variable temperature electrochemical impedance spectroscopy of U2AICI3S electrolyte ball-milled for 20 hours.

[0033] FIG. 14A shows a structure of sulfur-doped NaAICL showing edge shared tetrahedron of sulfur and chlorine anions. Sodium and aluminum occupancy is shared in one site while another 4a site (Na1) is fully occupied with sodium. An increase in sodium-ion conduction is possible as sodium can use the aluminum sites for hoping that are shared.

[0034] FIG. 14B shows a structure of chlorine-doped Na2S.

[0035] FIG. 15A shows lab powder XRD pattern KAICI4, K2AICl3S-instant reaction, and high- energy ball-milled K2AICI3S.

[0036] FIG. 15B shows Nyquist plots of potassium tetrachloroaluminate and the sulfur dopedsamples.

[0037] FIGS. 16A-16I show long-range structures of LiAICL and U2AICI3S, determined using Lab- X-ray diffraction and high-resolution X-ray diffraction, (a) Lab X-ray diffraction patterns of the as- milled LiAICL and U2AICI3S. The ICSD patterns of precursors and LiAICL monoclinic phase (P2i / c space group) are shown as references, (b) The magnified view of the selected 2q ranges in (a), (c) and (d) High-resolution X-ray diffraction patterns and the corresponding Rietveld refinement of LiAICU and U2AICI3S, respectively, (e) and (g) Monoclinic structures of LiAICU and Li1.6AICI3.4S06 with the P2i / c space group, respectively, obtained from refined high-resolution XRD patterns, (f) The structure of Li 1.6AICI3.4S0.6 viewed along the a-axis showing tetrahedral voids face- shared with Li-octahedra. (h) The visualization of partially occupied octahedral lithium at Wyckoff 2b position face-shared with highly distorted octahedral sites at Wyckoff 4e positions, (i) Possible lithium migration pathways.

[0038] FIG. 17 shows the6Li MAS NMR spectra of LiAICL and Li1.6AICI3.4S06.

[0039] FIGS. 18A-18D show the mean square displacement (MSD) of Li+in (a) LiAICL and (b) Li1.6AICI3.4S06 generated from AIMD simulations. Li+(yellow) probability density map of LiAICL (c) and Li1.6AICI3.4S06 (d) in a 2 x 2 x 1 cell based on AIMD simulations at 900 K.

[0040] FIGS. 19A-19D show the charge transport properties of LiAICL and Li1.6AICI3.4S06. (a) Nyquist plots of LiAICL and Li16AICI3.4S06. (b) Exemplary equivalent circuit fitting of the Nyquist plot for Li1.6AICI3.4S06 measured at 25 °C. (c) Electronic conductivities were determined using DC polarization, and (d) Arrhenius plots and activation energies for ion transport in LiAICL and Li1.6AICI3.4S0.6-

[0041] FIG. 20 shows the cyclic voltammogram of Li16AICI34S06 using carbon black (Super P) as the electronic conductive medium in 3Lii.6AICl3.4So.6:SP. An electrochemical stability window of 1.03 V to 2.40 is obtained for Li1.6AICI3.4S06.

[0042] FIGS. 21A-21C show the galvanostatic cycling of 2SE:TiS2 catholyte with argyrodite LiePSsCI as the separator, (a) Rate performance of Li-ln| Li6PS5CI|2SE:TiS2 cell (SE = LiAICL or Li1.6AICI3.4S06) followed by long-term cycling at C / 5, where C = 239 mAh / g. Voltage profile of Cycle 1 along with the 2ndcycles of each C-rate for a (b) Li-I n| LiePSsCI |2(Lii 6AICI3.4S0.6) :TiS2 cell and (c) Li-ln| Li6PS5CI|2(LiAICL):TiS2cell.

[0043] FIGS. 22A-22B show the differential capacity plots of Li-ln | LPSCI | 2SE:TiS2 cells using (a) Li1.6AICI3.4S06 and (b) LiAICI4 as the solid electrolyte (SE).

[0044] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.DETAILED DESCRIPTION

[0045] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0046] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0047] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0048] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0049] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0050] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0051] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0052] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.Definitions

[0053] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0054] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an excipient” include, but are not limited to, mixtures or combinations of two or more such excipients, and the like.

[0055] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0056] When a range is expressed, a further aspect includes from the one particular value and / or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. ‘about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.

[0057] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or subranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1 % to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%,and other possible sub-ranges) within the indicated range. Thus, for example, if a component is in an amount of about 1%, 2%, 3%, 4%, or 5%, where any value can be a lower and upper endpoint of a range, then any range is contemplated between 1% and 5% (e.g., 1% to 3%, 2% to 4%, etc.).

[0058] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0059] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible nonexpress basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0060] Disclosed are the components to be used to prepare the compositions of the invention as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if aparticular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C are disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively contemplated meaning combinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application including, but not limited to, steps in methods of making and using the compositions of the invention. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the methods of the invention.

[0061] It is understood that the compositions disclosed herein have certain functions. Disclosed herein are certain structural requirements for performing the disclosed functions, and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.

[0062] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0063] Unless otherwise specified, temperatures referred to herein are based on atmospheric pressure (i.e. one atmosphere).Solid Electrolytes and Methods of Making and Using the same

[0064] The present disclosure provides for chalcohalide solid electrolytes and the method of making and using chalcohalide solid electrolytes. The method of making can include using cost- effective precursors in the synthesis of chalcohalide solid electrolytes. The electrolytes have the general formula AaMbNcXdYeSf and can have relatively high ionic conductivity. Additionally, the synthesis of these electrolytes with high ionic conductivity can be achieved via a one-step mechanochemical approach. The electrolytes can be included as a component of different types of batteries, such as solid-state batteries. In a particular aspect, Li- and Na-superionic solid electrolytes made with low-cost precursors work well for producing energy storage devices, such as batteries (e.g., solid-state batteries), on a large scale.

[0065] In one aspect, the electrolytes have the formula AaMbNcXdYeSf, where A can be one of Li, Na, K, or any combination thereof; M can be Al, Ga, In, or any combination thereof; N can be Mg, Ca, Zn, or any combination thereof; X and Y can be, independently, F, Cl, Br, or I; and S is sulfur. Furthermore, a can be about 1 to about 4 or about 1.0, 2.0, 3.0, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 3.0 to 4.0); b can be about 0.5 to about 5.0 or about 0.5, 1.0, 2.0, 3.0, 4.0, or 5.0, where any value can be a lower and upper endpoint of a range (e.g., 0.5 to 3.0); c can be greater than or equal to 0 to about 1.5 or equal to 0.0, about 0.5, about 1.0, or about 1.5, where any value can be a lower and upper endpoint of a range (e.g., 0.5 to 1.0); d can be about 1 to about 5 or about 1.0, 2.0, 3.0, 4.0, or 5.0, where any value can be a lower and upper endpoint of a range (e.g., 4.0 to 5.0); e can be greater than or equal to 0 to about 3 or equal to 0.0, about 1 .0, about 2.0, or about 3.0, where any value can be a lower and upper endpoint of a range (e.g., 2.0 to 3.0); and f can be greater than 0 to about 3 or about 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.5). Furthermore, a, b, c, d, e, and f can be assigned values such that (a + 3b + 2c) is equal to (d + e + 2f). In some aspects, A is Li or Na, M is Al, and X is Cl. In other aspects, A is Li, M is Al and Ga, X is Cl, and Y is F.

[0066] In other aspects, a can be about 1 to about 2 or about 1.0, 1.5, or 2.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0). In other aspects, b can be about 0.5 to about 1.0 or about 0.50, 0.75, or 1.00, where any value can be a lower and upper endpoint of a range (e.g., 0.50 to 1.00). In other aspects, c can be about 0.1 to about 1.0 or about 0.1 , 0.3, 0.7, or 1.0, where any value can be a lower and upper endpoint of a range (e.g., 0.3 to 1.0). In other aspects, d can be about 2 to about 4 or about 2.0, 2.5, 3.0, 3.5, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 2.5 to 3.0). In other aspects, e can be greater than O to about 1 or about 0.1 , 0.3, 0.7, or 1.0, where any value can be a lower and upper endpoint of a range (e.g., 0.7 to 1.0).

[0067] In other aspects, the electrolytes can have the formula AaAlbCldSf, where A can be Li or Na. In some aspects, a can be about 2 to about 4 or about 2.0, 2.5, 3.0, 3.5, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 2.5 to 3.0); b can be about 0.5 to about 1.0 or about 0.50, 0.75, or 1.00, where any value can be a lower and upper endpoint of a range (e.g., 0.5 to 1.0); d can be about 2 to about 4 or about 2.0, 2.5, 3.0, 3.5, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 2.5 to 3.0); and f can be about 1 to about 3 or about 1.0, 1.5, 2.0, 2.5, or 3.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0).

[0068] In other aspects, the electrolytes can have the formula LiaAlbNcCldSf, where N is Ca or Zn. In some aspects, a can be about 1 to about 2 or about 1 .0, 1 .5, or 2.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0); b can be about 0.5 to about 1.0 or about 0.50, 0.75, or 1.00, where any value can be a lower and upper endpoint of a range (e.g., 0.50 to 1.00); c can be about 0.1 to about 1.0 or about 0.1 , 0.3, 0.7, or 1.0, where any value can be a lower and upper endpoint of a range (e.g., 0.3 to 1.0); d can be about 2 to about 4 or about 2.0, 2.5, 3.0, 3.5, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 2.5 to 3.0); and f can be about 1 to about 3 or about 1.0, 1.5, 2.0, 2.5, or 3.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0).

[0069] In other aspects, the electrolytes can have the formula LiaAlbCldBreSf. In some aspects, a can be about 1 to about 2 or about 1.0, 1.5, or 2.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0); b can be about 0.5 to about 1.0 or about 0.50, 0.75, or 1.00, where any value can be a lower and upper endpoint of a range (e.g., 0.50 to 1 .00); d can be about 2 to about 4 or about 2.0, 2.5, 3.0, 3.5, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 2.5 to 3.0); e can be greater than 0 to about 1 or about 0.1 , 0.3, 0.7, or 1.0, where any value can be a lower and upper endpoint of a range (e.g., 0.7 to 1.0); and f can be about 1 to about 3 or about 1.0, 1.5, 2.0, 2.5, or 3.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.0).

[0070] In another aspect, the electrolytes can have the formula Li2AlbiGab2CldFeS. In some aspects, b1 can be about 0.5 to about 1 .0 or about 0.50, 0.75, or 1 .00, where any value can be a lower and upper endpoint of a range (e.g., 0.50 to 0.75); b2 can be about 0.1 to about 0.5 or about 0.1 , 0.3, or 0.5, where any value can be a lower and upper endpoint of a range (e.g., 0.3 to 0.5); d can be from about 2.1 to about 2.9 or about 2.1 , 2.3, 2.6, or 2.9, where any value can be a lower and upper endpoint of a range (e.g., 2.3 to 2.6); and e can be from about 0.1 to 0.9 or about 0.1, 0.3, 0.6, or 0.9, where any value can be a lower and upper endpoint of a range (e.g., 0.3 to 0.6). In further aspects, b1 and b2 can have values such that (b1 +b2) - b.

[0071] In another aspect, the electrolytes can have the formula LiaAICIdSf. In some aspects, a can be about 1 .0 to about 2.0 or about 1.0, 1.1 , 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 1.7); d is from about 3.0 to about 4.0 or about 3.1 , 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 3.3 to 5.5); and f can be from about 0.1 to about 1.0 or about 0.1,0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, where any value can be a lower and upper endpoint of a range (e.g., 0.5 to 0.7).

[0072] In some aspects, the electrolytes can have the formula l^AIChS, Li4AIChS2, IX^AIChS, or K2AICI3S. In other aspects, the electrolytes can have the formula U2AICI3S, U4AICI3S2, or Na2AICl3S. In other aspects, the electrolytes can have the formula Li2AI0.9Ga0.1CI2.7F0.3S, Li2AI0.3Ga0.2CI2.4F0.6S, Li2AI07Ga0.3CI2.1F09S, or Li1.6AICI3.4S0.6-

[0073] The electrolytes disclosed herein can be characterized by various properties. In one aspect, the electrolytes disclosed herein can have relatively high ionic conductivity. The electrolytes can have an ionic conductivity of at least about 0.10 mS / cm, 0.30 mS / cm, 0.50 mS / cm, 0.70 mS / cm, or 1.00 mS / cm. In other aspects, the electrolytes can have an ionic conductivity of about 0.10 mS / cm to about 1.00 mS / cm or about 0.10 mS / cm, 0.30 mS / cm, 0.50 mS / cm, 0.70 mS / cm, or 1.00 mS / cm, where any value can be a lower and upper endpoint of a range (e.g., 0.50 mS / cm to 0.70 mS / cm). In another aspect, the electrolytes can be conductive over a temperature range of about -20 °C to about 100 °C or about -20 °C, 0 °C, 20 °C, 40 °C, 60 °C, 80 °C, or 100 °C, where any value can be a lower and upper endpoint of a range (e.g., 0 °C to 40 °C). In further aspects, the electrolytes can have an electronic conductivity of about 1.00 x 10'7S / cm to about 1.00 x 10‘10S / cm or about 1.00 x 10'7S / cm, 1.00 x 10'8S / cm, 1.00 x 10'9S / cm, or 1.00 x 10'10S / cm, where any value can be a lower and upper endpoint of a range (e.g., 1 .00 x 10-7S / cm to 1 .00 x 10-8S / cm). Exemplary methods for determining ionic conductivity and electronic conductivity are provided in the Examples.

[0074] In some aspects, the electrolytes have a monoclinic structure type in the P2i / c space group. In other aspects, the electrolytes have an orthorhombic structure type in the P2i2i2i space group. In other aspects, the electrolytes have a cubic structure type belonging to the Fm-3m space group.

[0075] The electrolytes described herein have unique X-ray diffraction (XRD) patterns. In some aspects, the X-ray powder diffractions can be performed using an X-ray wavelength of 1.5406 A. In some aspects, the electrolytes can have an X-ray powder diffraction pattern including peaks at 26.9, 31.2, and 44.8 ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A. In further aspects, the electrolytes with this XRD pattern can include U2AICI3S and / or U4AICI3S2. In other aspects, the electrolytes can have an X-ray powder diffraction pattern including peaks at 24.6 and 26.9 ± 0.2° 20 as measured by X-ray powder diffraction using an X- ray wavelength of 1.5406 A. In further aspects, the electrolytes with this XRD pattern can includeLi2AI09Ga0 1CI27F03S, Li2AI08Ga02CI24F06S, and / or Li2Alo 7Gao 3CI21Fo 9S. In other aspects, the electrolytes can have an X-ray powder diffraction pattern including peaks at 23.5 and 38.9 ± 0.2° 26 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A. In further aspects, the electrolytes with this XRD pattern can include Na2AICl3S. In still other aspects, the electrolytes can have an X-ray powder diffraction pattern including peaks at 28.4 and 40.6 ± 0.2° 26 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A. In further aspects, the electrolytes with this XRD pattern can include K2AICI3S.

[0076] The electrolytes described herein possess unique solid-state NMR spectra. The Li- containing electrolytes can have peaks at about -0.98 ppm, 0.15 ppm, 1.60 ppm and 2.43 ppm as determined by6Li solid-state NMR spectroscopy. In further aspects, the Li-containing electrolytes can have peaks at about -0.98 ppm, 0.15 ppm, and 1.60 ppm as determined by6Li solid-state NMR spectroscopy. The Na-containing electrolytes can have peaks at about 42.66 ppm as determined by23Na solid-state NMR spectroscopy. In other aspects, the Na-containing electrolytes can have peaks at about -15.04 ppm, -16.63 ppm, -19.17 ppm, -21.75 ppm, -23.21 ppm, -24.83 ppm, and 42.66 ppm as determined by23Na solid-state NMR spectroscopy. In other aspects, the Na-containing electrolytes can have peaks at about -15.04 ppm, -16.63 ppm, -21 .75 ppm, and 42.66 ppm as determined by23Na solid-state NMR spectroscopy. Exemplary methods for performing XRD and NMR measurements are provided in the Examples.

[0077] The electrolytes described herein possess good long-term cycling stability and rate performance, which makes the electrolytes described herein excellent candidates as electrolytes for all solid-state batteries (ASSBs). In one aspect, electrolytes described herein have a specific capacity of about 150 mAh / g to about 200 mAh / g at a discharge rate of 2 coulombs (C) in a battery cell. Exemplary methods for determining the capacity of the electrolytes described herein are provided in the Examples.

[0078] Also disclosed is a method for making chalcohalide solid electrolytes having the formula AaMbNcXdYeSf, where A can be one of Li, Na, K, or any combination thereof; M can be Al, Ga, In, or any combination thereof; N can be Mg, Ca, Zn, or any combination thereof; and X and Y can be, independently, F, Cl, Br, or I; and S is sulfur, a can be about 1 to about 4 or about 1.0, 2.0, 3.0, or 4.0, where any value can be a lower and upper endpoint of a range (e.g., 3.0 to 4.0); b can be about 0.5 to about 5.0 or about 0.5, 1.0, 2.0, 3.0, 4.0, or 5.0, where any value can be a lower and upper endpoint of a range (e.g., 0.5 to 3.0); c can be greater than or equal to 0 to about 1.5 or equal to 0.0, about 0.5, about 1.0, or about 1.5, where any value can be a lower and upperendpoint of a range (e.g., 0.5 to 1.0); d can be about 1 to about 5 or about 1.0, 2.0, 3.0, 4.0, or 5.0, where any value can be a lower and upper endpoint of a range (e.g., 4.0 to 5.0); e can be greater than or equal to 0 to about 3 or equal to 0.0, about 1.0, about 2.0, or about 3.0, where any value can be a lower and upper endpoint of a range (e.g., 2.0 to 3.0); and f can be greater than 0 to about 3 or about 0.1 , 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0, where any value can be a lower and upper endpoint of a range (e.g., 1.5 to 2.5). Furthermore, a, b, c, d, e, and f can be assigned values such that (a + 3b + 2c) is equal to (d + e + 2f). The method includes mixing a plurality of precursor compounds, such as salts, in various amounts in the solid state. In one aspect, the compounds are mixed together in stoichiometric amounts. In further aspects, the mixing can include grinding stoichiometric amounts of the compounds in different molar ratios. The compounds mixed together can include A2S; AX, AY, or a combination thereof; MX3, MY3, or a combination thereof; and NX2, NY2, or a combination thereof. A, X, Y, M, and N are as defined previously.

[0079] The compounds used to produce the electrolytes described herein are generally highly pure materials. In one aspect, each of the compounds has a purity of greater than 99%, greater than 99.5%, or greater than 99.9%. In one aspect, each compound used to produce the electrolytes is substantially anhydrous, where each compound is at least 95% moisture free, at least 98% moisture free, at least 99% moisture free, at least 99.9% moisture free, or 100% moisture free. In another aspect, each compound has less than 0.5 ppm water, less than 0.25 ppm water, or less than 0.1 ppm water.

[0080] In another aspect, the compounds can be mixed by mechanochemical milling. Mixing of the compounds can occur in a mixing jar or container using one or more balls to produce a complex motion that combines back-and-forth swings with short lateral movements. In one aspect, the compounds are mixed with one another for at least three hours, at least two hours, less than two hours, or less than one hour. In another aspect, the compounds are mixed from about 45 minutes to about 135 minutes or about 45 minutes, 60 minutes, 75 minutes, 90 minutes, 105 minutes, 120 minutes, or 135 minutes, where any value can be a lower and upper endpoint of a range (e.g., 60 minutes to 105 minutes). In one aspect, the compounds are mixed in an inert atmosphere such as, for example, nitrogen or argon. In one aspect, the inert atmosphere has less than 0.5 ppm oxygen, less than 0.25 ppm oxygen, or less than 0.1 ppm oxygen. After mixing, the mixture can be pelletized.

[0081] Now having described the aspects of the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of thepresent disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.Aspects

[0082] Aspect 1. A compound having the formula AaMbN0XdYeSf, whereinA is Li, Na , K, or any combination thereof;M is Al, Ga, In, or any combination thereof;N is Mg, Ca, Zn, or any combination thereof;X and Y are, independently, F, Cl, Br, or I;S is sulfur; a is from about 1 to about 4; b is from about 0.5 to about 5.0; c is greater than or equal to 0 to about 1.5; d is from about 1 to about 5; e is greater than or equal to 0 to about 3; f is greater than 0 to about 3; and the sum (a + 3b + 2c) is equal to the sum (d + e + 2f).

[0083] Aspect 2. The compound of Aspect 1 , wherein A is Li.

[0084] Aspect 3. The compound of Aspect 1 , wherein A is Na.

[0085] Aspect 4. The compound of any one of Aspects 1-3, wherein a is from about 1 to about 2.

[0086] Aspect 5. The compound of any one of Aspects 1-4, wherein M is Al.

[0087] Aspect 6. The compound of any one of Aspects 1-4, wherein M is Ga.

[0088] Aspect 7. The compound of any one of Aspects 1-4, wherein M is In.

[0089] Aspect 8. The compound of any one of Aspects 1-7, wherein b is from about 0.5 to about1.0.

[0090] Aspect 9. The compound of any one of Aspects 1-8, wherein N is Ca.

[0091] Aspect 10. The compound of any one of Aspects 1-8, wherein N is Zn.

[0092] Aspect 11. The compound of any one of Aspects 1-10, wherein c is zero.

[0093] Aspect 12. The compound of any one of Aspects 1-10, wherein c is from about 0.1 to about 1.0.

[0094] Aspect 13. The compound of any one of Aspects 1-12, wherein X is Cl

[0095] Aspect 14. The compound of Aspect 13, wherein d is from about 2 to about 4.

[0096] Aspect 15. The compound of any one of Aspects 1-14, wherein when e is greater than zero, Y is Br.

[0097] Aspect 16. The compound of Aspect 15, wherein e is greater than zero to about 1.

[0098] Aspect 17. The compound of Aspect 1, wherein A is Li or Na, M is Al, and X is Cl.

[0099] Aspect 18. The compound of Aspect 1 , wherein A is Li, M is Al and Ga, X is Cl, and Y is F.

[0100] Aspect 19. The compound of Aspect 1 , where the compound has the formula AaAlbCldSf, wherein A is Li or Na.

[0101] Aspect 20. The compound of Aspect 19, wherein a is from about 2 to about 4, b is from about 0.5 to about 1.0, d is from about 2 to about 4, and f is from about 1 to about 3.

[0102] Aspect 21. The compound of Aspect 1, wherein the compound has the formula LiaAlbNcCldSf, wherein N is Ca or Zn.

[0103] Aspect 22. The compound of Aspect 21 , wherein a is from about 1 or to about 2, b is from about 0.5 to about 1.0, c is from about 0.1 to about 1.0, d is from about 2 to about 4, and f is from about 1 to about 3.

[0104] Aspect 23. The compound of Aspect 1 , where the compound has the formula LiaAlbCldBreSf.

[0105] Aspect 24. The compound of Aspect 23, wherein a is from about 1 or to about 2, b is from about 0.5 to about 1, d is from about 2 to about 4, e is greater than zero to about 1 , and f is from about 1 to about 3.

[0106] Aspect 25. The compound of Aspect 1, wherein the compound has the formula LhAIChS, Li4AICI3S2, Na2AICI3S, or K2AICI3S.

[0107] Aspect 26. The compound of Aspect 1, wherein the compound has the formula Li2AlbiGab2CldFeS, wherein (b1 + b2) = b.

[0108] Aspect 27. The compound of Aspect 26, wherein b1 is from about 0.5 to about 0.9, b2 is from about 0.1 to about 0.5, d is from about 2.1 to about 2.9, and e is from about 0.1 to about 0.9.

[0109] Aspect 28. The compound of Aspect 1 , wherein the compound has the formula LLAICIdSf, wherein a is from about 1.0 to about 2.0, d is from about 3.0 to about 4.0, and f is from about 0.1 to about 1.0.

[0110] Aspect 29. The compound of Aspect 1, wherein the compound has the formula Li2AI0.9Ga0.1CI2.7F0.3S, Li2AI03Ga0.2CI2.4F06S, Li2AI0.7Ga0.3CI2.1F0.9S, or Li1.6AICI3.4S06.

[0111] Aspect 30. The compound of any one of Aspects 1-29, wherein the compound has an ionic conductivity of at least 0.10 mS / cm.

[0112] Aspect 31. The compound of any one of Aspects 1-29, wherein the compound has an ionic conductivity of at least 0.10 mS / cm to about 1.00 mS / cm.

[0113] Aspect 32. The compound of any one of Aspects 1-31, wherein the compound has an electronic conductivity less than 1.00 x 10'7S / cm.

[0114] Aspect 33. The compound of any one of Aspects 1-31, wherein the compound has an electronic conductivity of about 1.00 x 10"7S / cm to about 1.00 x 10'10S / cm.

[0115] Aspect 34. The compound of any one of Aspects 1-33, wherein the compound is conductive over a temperature range of about -20 °C to about 100 °C.

[0116] Aspect 35. The compound of any one of Aspects 1-34, wherein the compound has a monoclinic structure type with the space group P2i / c.

[0117] Aspect 36. The compound of any one of Aspects 1-35, wherein the compound has an X- ray powder diffraction pattern comprising peaks at 26.9°, 31.2°, and 44.8° ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A.

[0118] Aspect 37. The compound of any one of Aspects 1-35, wherein the compound has an X- ray powder diffraction pattern comprising peaks at 24.6° and 26.9° ± 0.2° 20 as measured by X- ray powder diffraction using an X-ray wavelength of 1.5406 A.

[0119] Aspect 38. The compound of any one of Aspects 1-37, wherein the compound has peaks at about -0.98ppm, 0.15ppm, and 1.60 ppm, as determined by6Li solid-state NMR spectroscopy.

[0120] Aspect 39. The compound of any one of Aspects 1-34, wherein the compound has an orthorhombic structure type with the space group P2i2i2i.

[0121] Aspect 40. The compound of any one of Aspects 1-34 or 39, wherein the compound has an X-ray powder diffraction pattern comprising peaks at 23.5° and 38.9° ± 0.2° 29 as measured by X-ray powder diffraction using an X-ray wavelength of 0.24 A.

[0122] Aspect 41. The compound of any one of Aspects 1-34, 39, or 40, wherein the compound has a peak at about 42.66 ppm, as determined by23Na solid-state NMR spectroscopy.

[0123] Aspect 42. The compound of any one of Aspects 1-34, wherein the compound has a cubic structure type with the space group Fm-3m.

[0124] Aspect 43. The compound of any one of Aspects 1-34 or 42, wherein the compound has an X-ray powder diffraction pattern comprising peaks at 28.4° and 40.6° ± 0.2° 29 as measured by X-ray powder diffraction using an X-ray wavelength of 0.24 A.

[0125] Aspect 44. The compound of any one of Aspects 1-34 or 39, wherein the compound has a capacity of about 150 mAh / g to about 200 mAh / g at a discharge rate of 2 coulombs (C).

[0126] Aspect 45. A method for making a compound having the formula AaMbNcXdYeSf, whereinA is Li, Na, K, or any combination thereof;M is Al, Ga, In, or any combination thereof;N is Mg, Ca, Zn, or any combination thereof;X and Y are, independently, F, Cl, Br, or I;S is sulfur; a is from about 1 to about 4; b is from about 0.5 to about 5.0; c is greater than or equal to 0 to about 1.5; d is from about 1 to about 5; e is greater than or equal to 0 to about 3; f is greater than 0 to about 3; and the sum (a + 3b + 2c) is equal to the sum (d + e + 2f), the method comprising: mixing in the solid state the following components: (i) A2S; (ii) AX, AY, or a combination thereof ; (i i i) MX3, MY3, or a combination thereof; and (iv) NX2, NY2, or a combination thereof to produce a first mixture.

[0127] Aspect 46. The method of Aspect 45, wherein the components are substantially anhydrous.

[0128] Aspect 47. The method of Aspect 45 or 46, wherein the components are mixed by mechanochemical milling.

[0129] Aspect 48. The method of any one of Aspects 45-47, wherein the components are mixed in an inert atmosphere.

[0130] Aspect 49. A compound produced by the method of any one of Aspects 45-48.

[0131] Aspect 50. A battery comprising the compound in any one of Aspects 1-44 or 49.

[0132] Aspect 51. The battery of Aspect 50, wherein the battery is a solid-state battery.EXAMPLES

[0133] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and / or methods claimed herein are made and evaluated, and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure.EXAMPLE 1Materials and Methods

[0134] LiCI (Sigma Aldrich), LiBr (Sigma Aldrich), and NaCI (Sigma Aldrich) were dried at 200 °C for 12 hours under a dynamic vacuum before being stored in an argon-filled glovebox. Anhydrous U2S (Alfa Aesar), anhydrous Na2S (Alfa Aesar), anhydrous AICI3 (Alfa Aesar), ZnCh (Thermo Scientific), CaCh (Thermo Scientific), and GaFs (Alfa Aesar) were received (packed under argon) and used without further purification. Stoichiometric amounts of precursors were ground using a mortar / pestle in different molar ratios for 5 minutes inside an argon-filled glovebox. After grinding, the hand-milled powder was transferred into a ZrC>2 jar containing two 10-mm balls as a grinding aid followed by evacuation to ensure the vacuum sealing of the jar to protect it from any external reaction. Mechanochemical mixing of the hand-milled powder in a ZrC>2 jar sealed under a vacuum was performed using a SPEX® 8000M MIXER / MILL® high energy ball mill (SPEX®SamplePrep,USA) for 10 hours. Afterward, the ball-milled powder, typically 130 mg, was pressed into an 8- mm pellet under pressure of ~400MPa inside an Argon-filled MBROUN glovebox. The resulting pellet after pressing had a thickness of ~1 mm and the pellet appeared shiny white.

[0135] Powder X-ray Diffraction - The as-milled samples were packed in a zero-background sample holder. KAPTON® film (DUPONT™, USA) was used to seal the samples to prevent exposure to humid air. XRD was performed using a RIGAKU® Smartlab powder diffractometer with Bragg - Brentano geometry at a voltage of 45 kV and current of 40 mA with Cu - Ka radiation (a = 1. 5406 A). The data was collected from 10-80 20 at a step size of 0.03 for 30 minutes.

[0136] Synchrotron X-ray Diffraction - Synchrotron X-ray diffraction (SXRD) measurement was carried out in capillary transmission mode at beamline APS@ANL, 17-BM-B at the Argonne National Lab, Illinois (ANL). The exact X-ray wavelength was refined to 0.24117 A. The sample was loaded inside a special glass capillary and the holder moved up and down during tests to ensure uniformity of measured results.

[0137] Rietveld Refinement - Rietveld refinement was carried out on powder lab XRD and synchrotron XRD data with the aid of GSAS-II software. Structural analysis from synchrotron PXRD of Li-ion conductor reveals a monoclinic phase belonging to the P2i / c space group of LiAICU (ICSD - 35275). The LiCI and LiAICL phases were used to refine the structure of LiAICL, while Li2S, LiCI, and LiAICL were used for structural refinement of the Li2AICl3S electrolyte. Sulfur occupancy was tested on all the chlorine sites and the result is only considered accurate when its occupancy is greater than 1% on the tested site. Lithium and aluminum occupancy were tested for the counter-cation sites of each other to find the most probable structure for the sulfur-doped electrolytes. Lab PXRD was used to refine the Li-ion conductor with the GaFs substitution. The possible anion cation combination occupancy on the doping strategy was tested. Structural analysis from lab PXRD of Na-ion conductor reveals an orthorhombic phase belonging to the P2i2i2i space group of NaAICL (ICSD -2307). The NaCI and NaAICL phases were used to refine the structure of NaAICL, while Na2S, NaCI, and NaAICL were used for structural refinement of the Na2AIChS electrolyte. Sulfur occupancy was tested on all the chlorine sites and the result is only considered accurate when its occupancy is greater than 1% on the tested site. Sodium and aluminum occupancy were tested for the counter-cation sites of each other to find the most probable structure for the sulfur-doped electrolytes. Site occupancies for the same site were constrained to 1 except for Na2.xSi.xClx. Atomic parameters for the same site were fixed for the substituents (Na, Ga, S, Cl, F, etc.).

[0002] Solid-state NMR -5Li,7Li, and23Na NMR experiments were performed using a Bruker Advance-Ill 500 spectrometer at Larmor frequencies of 73.6 MHz, 194.4 MHz, and 132.31 MHz, respectively. The MAS rate was 24 kHz. For6Li,7Li, and23Na, single-pulse NMR experiments were performed using n72 pulse lengths of 3.30 ps, 2.90 ps and 3.7 ps, respectively. The recycle delays were 500s s for6Li, 80 s for7Li, and 50 s for23Na.6’7Li NMR spectra were calibrated with LiCI(S) at -1.1 ppm and23Na NMR spectra was calibrated with NaCI(aq) at 0 ppm.7Li Ti and23Na relaxation time was measured with an inversion-recovery pulse sequence.

[0138] Electrochemical Impedance Spectroscopy (EIS) - The sample prepared was pressed in a mold of 8 mm split cell to make an approximately 1 mm thick pellet and sandwiched between 0.1 mm thick indium foils (~6 mm diameter) as blocking electrodes. The measurement of potentiostatic EIS was carried out on a Gamry electrochemical analyzer on a frequency range from 1 Hz to 5 MHz. The conductivities are calculated using impedance from Nyquist plots. Variable temperature EIS characterization was performed in the CSZ microclimate chamber from -20 °C to 70 °C using a Biologic SP-300. Conductivities at various temperatures were calculated using Nyquist plots and the Arrhenius-type plots were prepared to calculate the activation energy.

[0139] DC polarization - To measure the electronic conductivity, the DC polarization method was used.19In-house built split cells (diameter = 8 mm) using PEEK insulating cylinder and stainless- steel plungers as current collectors and indium as ion-blocking electrodes were used.Results and Discussion

[0140] X-ray Diffraction - First, structural disorder was induced while maintaining periodic structure by subjecting stoichiometric amounts of AlCh and Li2S to high mechanical stress via high-energy ball milling. Structure characterization using powder XRD (PXRD) reveals the presence of a monoclinic LiAICU phase for the pristine LAC composition as shown in Figure 1. Since dynamical anion disorder (anion polyhedral rotation) promotes cation mobility,1’12’20sulfur was introduced with higher polarizability to promote local disorder. With sulfur substitution, a trace amount of Li2S is observed, however, LAC still maintains its monoclinic phase. This confirms the preservation of the crystallinity of the SE.

[0141] The evolution of peaks corresponding to extra phases was observed even at low sintering temperatures. The weak and diffuse diffraction pattern of the annealed LACS suggests a decrease in the crystallinity of the material. Compared to the as-milled LACS, the annealed LACS has an intense peak of around 30° which is also present in the monoclinic LAC phase. Previousresearch has established the coexistence of dual phases for annealed samples.21The coexistence of the monoclinic phase suggests a distortion in the crystal structure of the material.21In addition, by simultaneously doping Ga in place of Al, and F in place of Cl, a decrease in crystallinity of the LACS phase was observed (Figure 10) with higher crystalline traces of Li2S and GaFs. However, with the aliovalent substitution such as Zn2+and Ca2+at the cation site, the structural transformation from a monoclinic to a spinel phase is observed (Figure 11).

[0142] In the case of the Na analog, similar mixed-anion effects on the structure, like in LACS, are observed. Stoichiometric amounts of NaCI, AlCh and Na2S were high-energy ball milled to synthesize NaAICL and Na2AICl3S. Structure characterization using powder XRD (PXRD) reveals the presence of an orthorhombic NaAICL (NAC) phase for the pristine NAC composition (Figure 2). Like in LiAICL, to promote disorder to enhance cation mobility,1sulfur was introduced with higher polarizability considering that it could help to flatten the energy landscape. With sulfur substitution, the amount of Na2S observed is higher than Li2S in the case of LACS, however, the NAC still maintains its orthorhombic phase. This confirms the sulfur substitution and preservation of the periodic structure of the synthesized SE.

[0143] In addition, synthesis of the potassium analog of LASC and NASC was attempted. The PXRD patterns of K2AICl3S (KACS) and KAICL (KAC) and the precursors are presented in Figure 15A. The diffraction pattern of prepared KAC matches with the diffraction pattern of KAICL (P21 space group). While grinding the precursors for K2AIChS, there was an instant exothermic reaction between K2S and AICI3 which generated fumes inside the glovebox and turned the mixture to black. To prevent the safety hazard, further preparation was discontinued. However, after the observed reaction, the as-prepared black powder mixture was ball milled. As shown in Figure 15A, the XRD pattern reveals the formation of KCI phase with Fm-3m space group for the burnt KACS. On ball milling for 10 hours, the crystallinity of KCI in K2AICIsS slightly decreases while preserving the diffraction pattern of Fm-3m space group.

[0144] Structure Refinement - Li2AIC S crystallizes as a monoclinic structure type in the P2i / c space group. Structural refinement was performed using GSAS-II on the synchrotron XRD data. The complete refinement parameters for the pristine and sulfur-substituted analog are provided in Table 4 to Table 9. From Table 5, refinement results reveal site disorder at the CI7S2’ site. This confirms that sulfur substitution via mechanochemical synthesis enforces local disorder made possible by the dynamic anion effect.22Notably, the refinement results show the presence of a trace amount of Li2S in the ball-milled sample. This result is consistent with the data from powderXRD and solid-state NMR (see below), thereby validating the accuracy of the structure refinement. In contrast to the Li site occupancies for LAC, a fraction of Li occupies the shared Al tetrahedral interstitial sites in LACS - creating more interconnected pathways for lithium-ion mobility. The fractional occupancy of lithium in tetrahedral sites particularly helps facilitate lithium hopping from one octahedral site to another octahedral site via connected tetrahedral sites. This validates the hypothesis that mechanochemical synthesis of the sulfur-substituted LAC generates a tetrahedral site occupation as confirmed by the low-intensity resonance in high-resolution6Li NMR analysis (see below). Notably, the formation of edge-sharing tetrahedrally coordinated lithium sites creates a pathway with lower energy barriers and correlates with the enhancement in the ionic conductivity of LACS.

[0145] For the Na analog, Na2AICl3S crystallizes as an orthorhombic structure type in the P2i2i2i space group. Structural refinement was performed using GSAS-II on the lab PXRD data. The complete table of refinement parameters for the pristine and sulfur-substituted analog are provided in Table 7, Table 8, and Table 9. From Table 8, the refinement results reveal disorder at the CI7S2-sites, similar to the lithium analog. The structure of Na2AICl3S consists of two different polyhedral oriented randomly within the structure. In the Na-only (Na1) polyhedral, six Cl atoms and one S atom are distributed along the vertices of the polyhedral to form a 7-coordinate geometry. Na2 and AI1 occupy the tetrahedral site and are coordinated to three Cl atoms and a vacancy-rich S atom. Utilizing two of the three Cl atoms and the S atom, Na2 in the tetrahedral interstitial is edge-sharing with Na-only (Na1) polyhedral.

[0146] Solid-state NMR - To advance understanding of the phases present and the local structure of LACS and Li4AICIsS2 (LACS2),6Li solid-state NMR was performed. Figure 5 compares the6Li NMR of LACS, LACS2, and LAC. The6Li NMR spectra of U2AICI3S reveal four distinct resonances at -0.98, 0.15, 2.43, and 1.60 ppm. The minor peak observed at 2.43 ppm, corresponds to the Li2S impurity23previously identified in the diffraction data. Drawing upon established semi-empirical correlations that connect the lithium coordination environment to6Li NMR shifts,24the signal at 0.15 ppm is ascribed to the tetrahedrally coordinated Li2 site. This assignment agrees with the result from structural refinement where the total amount of Li occupying the tetrahedral site from6Li NMR phase quantification and structural refinement has been determined to be 3%. A similar low-intensity signal (Li2) corresponding to the tetrahedrally coordinated lithium sites has been previously reported for LiAICU,1thereby validating the assignment. Conversely, the resonance at -0.98 ppm is assigned to the octahedrally coordinatedLi 1 site. The main signal, exhibiting a narrow full-width-half-maximum (FWHM) of 24.5 Hz at room temperature originates from rapid Li+hops, hindering the spectral resolution of Li sites characterized by different coordination numbers.24A significant increase in the peak intensity of Li2S in LACS2 was observed compared to LACS (Figure 4). This is not surprising since twice the stoichiometric amount of Li2S used for the synthesis of LACS is required for LACS2, thereby increasing the number of impurity phases from incomplete reaction and / or residual precursor. The presence of Li2S has been further validated from powder XRD (Figure 1) results and structural refinement (Figure 2D) where trace amounts of Li2S were observed. The highest intensity peak of LACS2 shows a shoulder that resonates at - 0.79 ppm (see Figure 5). The asymmetry of this peak suggests the presence of an unknown phase in LACS2 which is absent in LACS. In addition, there is an extra peak assigned to Li1.69S0.38CI0.32 that resonates at 1.60 ppm - which is more evident in LACS2 (Figure 3B). This is likely to be a metastable phase formed during the ball milling process.

[0147] The ion diffusion mechanism in ternary halides which extends to normal-spinel type and inverse-spinel type structures has been described as that in which tetrahedral coordinated Li-ions migrate using octahedral interstitials.2526As expected, the ionic conductivity of some SEs in this family such as LLZnCL has been reported to be considerably low owing to the presence of only octahedrally coordinated sites for lithium ions.25This amplifies the need to explore routes that ensure the presence of tetrahedrally coordinated lithium sites where vacancies are preferentially generated to enhance Li+mobility.

[0148] 7Li spin-lattice relaxation time (T1) is a useful indicator of ion dynamics. Table 1 confirms that LACS has a shorter T1 compared to LAC and LACS2, which suggests faster ion motion.27Table 1 :7Li spin-lattice relaxation time (T1) of LAC, LACS, and LACS2Sample7Li T1[s]Li2 Li1LiAICL 9.24Li2AICI3S 1.15 8.34Li4AICI3S21.19 8.73

[0149] Figure 6 compares the MAS23Na NMR spectra of NAC and NACS. NAC displays resonances at -21.75 ppm and -23.21 ppm with asymmetric line broadening due to second-orderquadrupolar coupling.6A minor peak with very low intensity resonates at -24.83 ppm. The23Na MAS spectrum of NACS displays an intense resonance at 42.66 ppm assigned to Na2-xSi-xClx. This resonance is quite distinct from that of Na2S in that it is shifted more upfield suggesting the incorporation of chlorine from the NAC phase into the Na2S structure. Specifically, the shift upfield for Na2.xSi-xClx may be attributed to the induced changes in the local structure owing to the proximity of NAC. The weak signal at 0 ppm originates from a minimal amount of unreacted NaCI. Notably, there are six low-intense resonances further upfield at -15.04, -16.63, -19.17, -21.75, -23.21 and -24.83 ppm. The resonances at -21.75 and -23.21 ppm may be attributed to Na1 which fully occupies the 4a site in the octahedral prism polyhedron and Na2 which shares the tetrahedral 4a site with AI1 .

[0150] These resonances may depict different coordination environments that may not be prominent in the structural refinement of the diffraction data. Specifically, the significant site disorder in NACS, introduces a distribution of local environments for Na+within the disordered region. The resonances at -15.04, -16.63, and -21.75 are therefore attributed to disordered Nai+xAICU-xSx from the NACS phase. Notably, the second-order quadrupolar line shape is not so prominent in NACS further corroborating the observation that the Na occupying the tetrahedral site may not be distinctly described by a perfect tetrahedral, but rather by a random distribution of S2' and Cl’.24The Ti of NACS is shown in Table 2.Table 2:23Na spin-lattice relaxation time (Ti) of Na2AIChSSample23Na Ti[s]Na1 Na2Na2AICI3S 0.45 0.61

[0151] Electrochemical Properties - To probe the alkali-ion dynamics of all prepared materials electrochemical impedance spectroscopy (EIS) was performed and the corresponding Nyquist plots are presented in Figures 7A, 8A, and 9A with a corresponding exemplary equivalent circuit fitting shown in Figures 7B, 8B, and 9B. The EIS analysis data are given in Table 3 and Table 10. For the composition of LACS the ionic conductivity was at least twenty-fold greater than pristine LiAICU at room temperature.9Based on fitted resistance from the Nyquist plot using equivalent circuit modeling (exemplary fit given in Figure 7B), LAC, LACS, LACS2, and LAG0.2CFS achieved an ionic conductivity of 0.0086 mS cm-1, 0.18 mS cm-1, 0.13 mS cm-1, and 0.35 mS cm-1respectively (Figure 7A and 8A). As shown in Figure 12, the enhancement in ionic conductivity of the LACS may be attributed to the edge-sharing tetrahedron which also connects to the octahedron. The DC polarization plots of LACS, LACS2, and LAG0.2CFS are given in Figures 7C, 8C, and 9C. The current value upon plateauing corresponds to an electronic conductivity of 5.43 x 10-8S cm-1, 7.73 x 10'8S cm'1, and 4.75 x 10'9S cm'1for LACS, LACS2, and LAG0.2CFS, respectively, thereby confirming the negligible electronic contribution to the ionic conductivity of the samples. The significant increase in ionic conductivity can be attributed to the local disorder that causes the tetrahedron connection with near boring octahedrons. The energy barrier for Li- ion transport was then calculated form the variable temperature EIS measurement between the temperature range of 0 °C to 70 °C and representative Nyquist plots are shown in Figure 13. The Arrhenius plot of LAC, LACS, and

[0152] LACS2 are shown in Figure 7D. The decrease in activation energy is observed with sulfur doping on LAC from 0.51 eV to 0.44 eV. This correlates with the increase in ionic conductivity result, according to the Nernst-Einstein equation.28

[0153] Additionally, Na-ion diffusion was probed in the synthesized SEs using EIS. At an optimal composition of NACS, approximately a sixty-fold increase in ionic conductivity than pristine NAC is observed at room temperature.9Based on the fitting of the Nyquist plot, an ionic conductivity of 0.15 mS cm-1is achieved for NACS (Figure 9A). The significant increase in conductivity may be attributed to the local disorder that significantly enhances Na-ion mobility. In further detail, as shown in Figure 14, the enhancement in ionic conductivity of the NACS also can be attributed to the edge-sharing between the polyhedra which creates a more favorable environment for Na+transport. The ion diffusion mechanism in ternary halides which extends to normal-spinel type and inverse-spinel type structures has been described as that in which tetrahedral coordinated lithium ions migrate using octahedral interstitials.2526Figure 9B shows the equivalent circuit fitting for the Nyquist plot of NACS at 25 °C, suggesting there is negligible grain boundary resistance. The DC polarization of NAC and NACS (Figure 9C) was performed at the constant potential of 0.1 V and the current at the plateau was used to calculate the resistance using Ohm’s law. The electronic conductivity is hence calculated and corresponds to an overall electronic conductivity of 4.31 x io-9S / cm and 4.07 x 1Q-9S / cm for NAC and NACS, respectively, which confirms the negligible electronic contribution to the overall ionic conductivity for the samples. The Arrhenius plot of NAC and NACS are shown in Figure 9D. The energy barrier for Na-ion transport for NAC and NACS was determined to be 0.46 eV and 0.41 eV between the temperature range of 0 °C to70 °C. This confirms the increase in ionic conductivity is due to the decrease in the energy barrier after the introduction of sulfur to sodium tetrahaloaluminate.

[0154] Despite the futile attempt to synthesize KACS, the EIS analysis was performed on the prepared materials. Since there was no evident semicircle from the Nyquist plot, the activation energy and ionic conductivity were not determined.

[0155] The presence of octahedral and tetrahedral sites has been established for ternary metal halides such as Li2MgCl4 and LiAICU where intrinsic tetrahedral and octahedral interstitial sites govern the ion conduction mechanism.1'9'25'26As expected, these materials possess relatively higher conductivity owing to the modified structure that facilitates ion hopping from the 4e octahedral site to the 4e tetrahedral site.1This 2D conduction pathway from Litet-Lioct-Litet has been poised as one that could be generated via mechanochemical synthesis.1Indeed, high-resolution6Li NMR of LACS and LACS2 in this present study reveals the two resonances at -0.98 and 0.15 ppm assigned as lithium octahedral and tetrahedral sites.9'2526It then becomes more plausible to relate the origin of the higher conductivity to the S27CI' site disorder and the presence of edgesharing tetrahedrally coordinated lithium sites.Table 3. Different compositions of prepared AaMbNcXdYeSf SEs and their corresponding ionic conductivity, electronic conductivity, activation energy, and Arrhenius prefactor at room 25 °C.Composition oDc, 25 °c EaLog(Oo)[S cm'1] [ ] [eV] [S cm'1K]LiAICU - BM 8.65 * 10'63.49 x 10'80.51 6.55U2AICI3S - BM 1.80 x 10-4 5.43 x W80.44 6.07U4AICI3S2 - BM 1.30 x 10-47.73 x IO'80.46 6.27Li2AI0.9Ga0.1CI27F0.3S - BM 1.70 x IO46.12 x IO80.49 7.04Li2AI0.8Ga0.2CI24F0.6S - BM 3.50 x 10-44.75 x 10‘90.44 6.43Li2AI0.7Ga0.3CI21F0.9S - BM 1.50 x 10-43.16 x 10-90.46 6.51NaAICI4- BM 3.10 x W64.31 x W90.46 4.86Na2AICI3S - BM 1.5 x 10’44.07 x 10'90.41 5.63Table 4. Rietveld-refinement results of synchrotron diffraction data at room temperature for the mechanochemically synthesized LiAICU.LiAICU - Ball milled for 20 h.Composition: LiAICULattice parameter: a = 7.0035(7), b = 6.5088(6), c = 13.0008(8), a = g = 90.000, b = 93.34(7),Unit-cell volume = 591.62(8) A3Density of U2AICI4 = 1.973 g / cm3Rwp= 5.482 %, Space group P2i / c, Impurity phases: 2.1 wt% of LiCIName Atom Wycoff Atomic coordinates Occupancy UiS0position x y zLi1 Li 4e 0.176(3) 1.009(4) 0.380(2) 1 0.038(6)AI1 Al 4e 0.7098(8) 0.329(1) 0.9006(5) 1 0.039(2)CI1 Cl 4e 0.6944(8) 0.1834(8) 0.0459(5) 1 0.045(2)CI2 Cl 4e 0.8085(8) 0.6225(8) 0.9265(5) 1 0.036(2)CI3 Cl 4e 0.9232(8) 0.1819(9) 0.8136(5) 1 0.038(2)CI4 Cl 4e 0.4469(8) 0.3062(8) 0.8127(5) 1 0.035(2)Table 5. Rietveld-refinement results of synchrotron diffraction data at room temperature for the mechanochemically synthesized U2AICI4S.Li2AICI3S - Ball milled for 20 h.Composition: Li103AI0.97CI3.57S0.43Lattice parameter: a = 7.0195(8), b = 6.5237(8), c = 13.003 (2), a = g = 90.0000, b = 93.47(1), Unit-cell volume = 594.38(8) A3;Density of Lii.i5Alo.85CI3.68So.32= 1 941 g / cm3Rwp= 5.76 %, Space group P2i / cImpurity phases: 23.2 wt% of Li2S and 3.3 wt% of Li2-xSi-xClxName Atom Wycoff Atomic coordinates Occupancy UiS0position x y zLi1 Li 4e 0.17(1) 0. 99(1) 0.364(6) 1 0.072(6)Li2 Li 4e 0.719 0.329 0.902 0.030(7) 0.023(3)AI2 Al 4e 0.719(2) 0.329(2) 0.902(1) 0.970(4) 0.026(3)CI1 Cl 4e 0.677(2) 0.195(1) 0.0500(8) 1 0.039(3)CI2 Cl 4e 0.945(2) 0.160(2) 0.811(1) 1 0.031(3)CI3 Cl 4e 0.814(2) 0.619(1) 0.924(1) 1 0.016(2)CI4 Cl 4e 0.464(2) 0.290(2) 0.806(1) 0.566(6) 0.015(4)S4 S 4e 0.464 0.290 0.806 0.434(6) 0.054(3)Table 6. Na1.93S0.92CI0.07 phase from Rietveld-refinement results of XRD at room temperature for the mechanochemically synthesized Na2AICl4S.Refined composition: U1.8.S0.8CI0.2Lattice parameter: a = 5.7138(7), a = b = g = 90.0000,Unit-cell volume = 186.54(5) A3;Density of Na2AICl3S = 1.867 g / cm3Space group Fm-3mName Atom Wycoff Atomic coordinates Occupancy UjS0position x y zLi Li 8c 0.25 0.25 0.25 0.901(1) 0.014(5)S S 4a 0 0 0 0.801(1) 0.010(1)Cl Na 4a 0 0 0 0.199(3) 0.017(2)Table 7. Rietveld-refinement results of X-ray diffraction data at room temperature for the mechanochemically synthesized NaAICkNaAICU - Ball milled for 20 h.Lattice parameter: a = 10.3406(2), b = 9.8956(2), c = 6.1723(6), a = b = g = 90.0000,Unit-cell volume - 631.59(8 A3Density of NaAICL = 2.017 g / cm3R„p= 4.190 %, Space group P2i2i2i, Impurity phases: 2.9 wt% of NaCIName Atom Wycoff Atomic coordinates Occupancy UjS0position x y zNa1 Na 4a 0.120(2) 0.218(1) 0.689(2) 1 0.063(6)AI1 Al 4a 0.0380(9) 0.483(2) 0.207(2) 1 0.033(4)CI1 Cl 4a 0.0312(6) 0.492(1) 0.556(1) 1 0.048(3)CI2 Cl 4a 0.145(1) 0.316(1) 0.113(2) 1 0.047(4)CI3 Cl 4a 0. 3475(7) 0.024(1) 0.923(1) 1 0.038(3)CI4 Cl 4a 0.382(1) 0.336(1) 0.572(2) 1 0.049(4)Table 8. Rietveld-refinement results of XRD at room temperature for the mechanochemically synthesized NazAIC S.Refined composition: Na1.14AI0.86CI3.62S0.38Lattice parameter: a = 10.361(1), b = 9.890(1), c = 6.1765(6), a = b = g = 90.0000,Unit-cell volume = 632. 85(8) A3;Density of Na2AICl3S = 1.993 g / cm3Rwp= 3.865 %, Space group P2i2i2iName Atom Wycoff Atomic coordinates Occupancy UjS0position x y zNa1 Na 4a 0.117(3) 0. 211(3) 0.696(4) 1 0.036(7)AI1 Al 4a 0.039(2) 0.481(3) 0.215(3) 0.859(3) 0.015(6)Na2 Na 4a 0.039 0.481 0.215 0.141(4) 0.015CI1 Cl 4a 0.031(2) 0.493(4) 0.553(3) 1 0.041(9)CI2 Cl 4a 0.141(7) 0.307(9) 0.111(7) 0.619(2) 0.04(2)CI3 Cl 4a 0.344(2) 0.018(3) 0.921(4) 1 0.030(8)CI4 Cl 4a 0.374(2) 0.333(2) 0.570(4) 1 0.012(8)S2 S 4a 0.144 0.314 0.105 0.381(2) 0.04Table 9. Na1.98S0.92CI0.07 phase from Rietveld-refinement results of XRD at room temperature for the mechanochemically synthesized Na2AICl4S.Refined composition: Na1.98.S0.92CI0.07Lattice parameter: a = 6.5389(7), a = b = g = 90.0000,Unit-cell volume - 279.59(3) A3;Density of NazAIChS = 1.867 g / cm3Space group Fm-3mName Atom Wycoff Atomic coordinates Occupancy UjS0position x y zNa Na 8c 0.25 0.25 0.25 0.989(1) 0.011(1)S S 4a 0 0 0 0.920(1) 0.012(1)Cl Na 4b 0.5 0.5 0.5 0.073(3) 0.153(6)Table 10. Different compositions of prepared AaMbNcXdYeSf SEs and their corresponding ionic conductivity at room 25 °C.Com position ODC, 25 °c[S / cm]LiAICk - BM 8.65 x IO’6LiAlo.5Zno.5d35 - BM 6.68 x 107Li1.5Alo.5Zno.5CI4 - BM 5.60 x IO’6Li1.5Alo.5Zno5CI4 - 250 °C 4.90 x IO’6Li1.2Alo.8Cao.2CI4 - 200 °C 1.27 x IO’7Li1.5Alo.6Cao.4CI4 - 200 °C 1.68 x 10-7LiAICI3.5Bro5- BM 6.40 x 1Q-6

[0156] EXAMPLE 2

[0157] Material Synthesis

[0158] LiCI (Sigma Aldrich) was dried at 200 °C for 12 hours under a dynamic vacuum before being stored in an argon-filled glovebox. Anhydrous Li2S (Alfa Aesar) and ultra-dry AICI3 (Alfa Aesar) were used as received and handled under argon. Stoichiometric amounts of precursors were ground using a mortar / pestle for 5 minutes inside an argon-filled glovebox. The hand-milled powder was transferred into a ZrO2jar containing two 10-mm balls as milling media. After the jar was vacuum sealed, mechanochemical mixing was performed using a SPEX 8000M MIXER / MILL (SPEXOSamplePrep, USA) for 20 hours. Afterward, the ball-milled powder, typically -130 mg,was pressed into a pellet of 8 mm in diameter under -400 MPa inside an argon-filled Mbraun glovebox. The resulting pellet had a thickness of -1.2 mm and appeared shiny white.

[0159] Powder X-ray Diffraction - The as-milled samples were packed in a zero-background sample holder. KAPTON® film (DUPONT™, USA) was used to seal the samples to prevent exposure to humid air. Powder X-ray Diffraction (PXRD) was performed using a RIGAKU® Smartlab powder diffractometer with Bragg - Brentano geometry at a voltage of 45 kV and current of 40 mA with Cu - Ka radiation (a = 1.540562 A). The data was collected in the 26 range of IQ- 800at a step size of 0.03° for 30 minutes.

[0160] Synchrotron X-ray Diffraction - Synchrotron X-ray diffraction (SXRD) measurements were carried out in the transmission mode at the 17-BM-B beamline, APS, at Argonne National Lab (ANL), Illinois. The exact X-ray wavelength was refined to 0.24117 A. The sample was loaded inside a special glass capillary, and the holder was moved up and down during tests to ensure uniformity of the measured results.

[0161] Rietveld Refinement - Rietveld refinement of the lab and synchrotron PXRD data was performed using the GSAS-II software. Structural analysis of the synchrotron PXRD data on LiAICU and U2AICI3S reveals a monoclinic phase belonging to the P2i / c space group of LiAICU (ICSD - 35275). Sulfur occupancy was tested on all the chlorine sites, and the result was only considered accurate when sulfur occupancy was greater than 1% on the tested site. Lithium and aluminum occupancy were tested for the counter-cation sites of each other to find the most probable structure. Atomic parameters for the site were fixed for the substituents (S, Cl, etc.).

[0162] Computational Approach - All density functional theory (DFT) energy calculations and ab initio molecular dynamics (AIMD) simulations were carried out in the Vienna ab initio simulation package (VASP).18The projector-augmented-wave (PAW) approach was used.19Perdew-Burke- Ernzerhof generalized-gradient approximation (GGA-PBE) was chosen as the exchangecorrelation functional using the latest PAW potential files available in VASP.20Python Materials Genomics (Pymatgen) package21was used to optimize the structures of U2AICI3S. 10 supercells with different local environments were generated based on the 2 x 2 x 1 supercell of the LACS obtained from the high-resolution XRD structure refinement. Geometry optimization of the generated supercells was carried out using DFT calculations. The AIMD simulations22were based on the canonical ensemble for over 80 ps with a time step of 2 fs. The temperature was initialized at 100 K and elevated to the target value for the simulations.

[0163] Solid-state NMR-6Li and7Li NMR experiments were performed using a Bruker Advance- Ill 500 spectrometer at Larmor frequencies of 73.6 MHz and 194.4 MHz for6Li and7Li, respectively. The magic-angle-spinning (MAS) rate was 24 kHz. Single-pulse MAS6Li and7Li NM experiments were performed using TT / 2 pulse lengths of 3.30 ps and 2.90 s, respectively. For U2AICI3S, the recycle delays were 500 s for6Li and 80 s for7Li, while a recycle delay of 500 s for6Li and 90 s for7Li was utilized for LiAICk7Li NM spectra were calibrated with LiCI(s) at - 1.1 ppm, and7Li T1 relaxation time was measured with an inversion-recovery pulse sequence.

[0164] Variable-temperature7Li T1 relaxation NMR experiments were performed using a Bruker Avance-I 300 MHz Spectrometer from 25 to 70 °C. An inversion recovery pulse sequence with a TT / 2 pulse length of 2.63 ps was utilized. The7Li Larmor frequency was 116.6 MHz. Sample powders were packed into 4 mm ZrC>2 rotors under Argon and spun at a MAS rate of 10 kHz.

[0165] A6Li | SE 16Li symmetrical cell was assembled in an argon-filled glovebox for the6Lia7Li tracer exchange experiment. The cell was then subjected to galvanostatic cycling for 3 days at a current density of 5 pA cm-2to drive the diffusion of6Li+ions from the6Li foil into the U2AICI3S pellet. Following the galvanostatic cycling,6Li MAS NMR experiments were performed on the cycled U2AICI3S pellet using the Bruker Advance-Ill 500 spectrometer at a spinning rate of 24 kHz, using the same parameters as described above.

[0166] Electrochemical Impedance Spectroscopy (EIS) - The samples were pressed in a mold of 8-mm diameter to make 1.3-mm thick pellets, which were sandwiched between Indium of diameter 6mm (about 0.24 in) followed by stainless steel plungers as ion-blocking electrodes. The measurement of potentiostatic EIS was carried out on a Biologic SP-300 electrochemical analyzer within a frequency range from 7 MHz to 1 Hz using a voltage of 10 mV. The conductivities are calculated using resistance obtained by fitting the Nyquist plots using an equivalent circuit model. Variable-temperature EIS characterization was performed in the CSZ microclimate chamber from -20 °C to 70 °C using a Biologic SP-300, and Arrhenius-type plots were used to calculate the activation energies and Arrhenius prefactors.

[0167] DC Polarization - The DC polarization method was used to measure the electronic conductivity.23In-house-built split cells (diameter = 8 mm) using PEEK insulating cylinder and stainless-steel plungers as current collectors and indium foils (~6 mm diameter) as ion-blocking electrodes were used.

[0168] Cyclic Voltammetry (CV) and Galvanostatic Cycling of ASSB Half-cells -ASSB halfcells were assembled using pressure cells constructed in-house, using a PEEK casing of 10 mm diameter and stainless-steel plungers. For CV measurements, the initial steps involved pressing 100 mg of LiAICU (or U2AICI3S) at 300 MPa for 10 s. Then, roughly 10 mg of the manually mixed 3SE:carbon black (C: Super P) composite was evenly spread and pressed at 300 MPa for 10 s. On the opposite side of the LiAICL (or U2AICI3S) pellet, a piece of indium (In) foil measuring 5 / 16 inch in diameter and 0.1 mm in thickness, with an approximate weight of 32 mg was attached. Subsequently, lithium foil with a 3 / 16-inch diameter and weighing around 1 mg was pressed onto the In foil to form Li-ln and used as the counter electrode, giving a final cell setup of Li- ln|SE|3SE:C. With the cell sealed using vacuum grease, it was subjected to electrochemical cycling under an estimated stack pressure of approximately 30 MPa at 22 °C. CV measurements were conducted with a scan rate of 0.2 mV s-1from 0 to 4 V vs. Li-ln.

[0169] To prepare the composite cathode (or catholyte) for galvanostatic cycling, TiS2 (Sigma Aldrich, 99.9%) was initially dried at 200 °C for 12 hours, then subjected to ball milling for 5 hours at 300 rpm to reduce particle size. Subsequently, LiAICU or U2AICI3S was combined with TiS2 at a TiS2:SE mass ratio of 1 :2 and ground together using a mortar and pestle for 10 minutes. LiePSsCI, synthesized following the established method by Patel et al.,12was pressed into pellets at 300 MPa for 10 seconds as the separator. For the half-cell assembly, 12 mg of the catholyte was evenly spread onto one side of the Li6PSsCI pellet, achieving an aerial loading of approximately 1.25 mAh cm-2, followed by further pressing at 300 MPa for 10 seconds. A Li-ln alloy foil was affixed to the opposite side of the Li6PSsCI pellet to assemble the Li- ln|Li6PS5CI|2SE:TiS2 (SE: LiAICL or U2AICI3S) half cells. Finally, the cells were sealed with vacuum grease and subjected to controlled cycling conditions at 22°C with a stack pressure of ~30 MPa, within a voltage window of 1-2.5 V vs. Li-ln. For rate performance evaluations, the cells underwent cycling for 5 cycles at each of the following rates: 0.1C, 0.2C, 0.5C, 1 C, and 2C, with C representing the charge-discharge rate. Correspondingly, these rates translate to current densities of 0.14 mA cm'2, 0.28 mA cm-2, 0.70 mA cm-2, 1.40 mA cm-2, and 2.80 mA cm-2, respectively. Subsequently, long-term stability testing was conducted over 175 cycles at 0.2C.

[0170] RESULTS AND DISCUSSION

[0171] X-ray Diffraction and Structure

[0172] X-ray diffraction (XRD) was employed to investigate the long-range structure of the synthesized solid electrolytes. The powder XRD confirms the presence of a monoclinic LiAICU phase. With sulfur substitution, the long-range monoclinic structure is maintained for LhAIChS. However, the weak and diffuse diffraction pattern of the as-milled Li2AIChS suggests a decrease in the crystallinity of the material. Rietveld refinement was performed against high-resolution XRD data using GSAS-II. Figures 16c-f show the diffraction patterns and the refined structures. For LiAICL, the crystalline phase was refined with a monoclinic structure type in the P2i / c space group. The structure is built from distorted l_iX6octahedra and AICLr tetrahedra. Two LiCle5' octahedra are edge-shared to form l_i2Clio8' dimers.1AICLr tetrahedra are isolated from one another. All the atoms in the structure occupy only the 4e Wyckoff positions, leaving all other sites, i.e., 2a, 2b, 2c, and 2d Wyckoff positions, vacant (see Figure 16e). The arrangement of atoms is characterized by a slightly distorted hexagonal cubic packed (hep) Cl- sublattice, where octahedral and tetrahedral interstices are filled by Li+and Al3+, respectively.1In addition, each AICU tetrahedron is linked to one Li-CI dimer via two edges and to two other dimers through one corner each (Figure 16e).

[0173] Similarly, Li2AIChS crystallizes in the P2i / c space group. However, different from LiAICU, the unit cell consists of three octahedrally coordinated cation sites - Li 1 at 4e, Li2 at 2a, and Li3 at the 2a Wyckoff position; and tetrahedrally coordinated Al at the 4e Wyckoff position. Sulfur and chlorine atoms co-occupy the 4e anionic site, yielding a disordered anion sublattice. Along the c- direction, the structure exhibits three distinct cation layers (Figure 16g). In the first layer, Li2 octahedra (LiCle)5' edge-share with Li1 (LiCIs^So.e)56' and corner-share with the tetrahedrally coordinated Al. In the second layer, Li3 octahedra (LiCl4.sSi.2)62“ face-share with Li1 (Figure 16h), and both Li1 and Li3 octahedra share corners with the tetrahedrally coordinated Al. In the third layer, the Al sites face-share with Li3 and edge-share with Li 1 and Li2 octahedra. In addition, the edge-sharing Li1 , Li2, and Li3 octahedra produce tetrahedral voids (Figure 16f). The complete refinement parameters for LiAICL and Li2AICIsS are provided in Table 11 to Table 13. The refinement reveals the actual composition of the nominal Li2AIChS is Li1.6AICI3.4S06, which exhibits mixed CI7S2' site occupancies in the structure. A trace amount of Li2S is identified in the ball- milled Li2AIChS sample, consistent with the data from the powder XRD. The refined composition, Li1.6AICI3.4S06, is adopted hereafter.TH 930603-2120 FSU 23-071 PRCWOTable 11. Rietveld-refinement results of high-resolution X-ray diffraction data at room temperature for the mechanochemically synthesized LiAICL.LiAICU - Ball milled for 20 h.Composition: LiAICLLattice parameter: a = 7.0035(7), b = 6.5088(6), c = 13.0008(8), a = g = 90.000, b = 93.34(7), Unit-cell volume = 591.62(8) A3Density of U2AICI4 = 1 .973 g / cm3Rwp= 5.482 %, Space group P21 / c, Impurity phases: 2.8 wt% of LiCIName Ato Wycoff Atomic coordinates Occupancy UjS0m position - x y zLi1 Li 4e 0.176(3) 1.009(4) 0.380(2) 1 0.038(6)AI1 Al 4e 0.7098(8) 0.329(1) 0.9006(5) 1 0.039(2)CI1 Cl 4e 0.6944(8) 0.1834(8) 0.0459(5) 1 0.045(2)CI2 Cl 4e 0.8085(8) 0.6225(8) 0.9265(5) 1 0.036(2)CI3 Cl 4e 0.9232(8) 0.1819(9) 0.8136(5) 1 0.038(2)CI4 Cl 4e 0.4469(8) 0.3062(8) 0.8127(5) 1 0.035(2)TH 930603-2120 FSU 23-071 PRCWOTable 12. Rietveld-refinement results of the high-resolution X-ray diffraction data for the mechanochemically synthesized U2AICI3S.Refined composition : Li1.6AICI3.4S06Lattice parameter: a = 7.0207(8), b = 6.5206(8), c = 13.004(2), a = g = 90.0000, b = 93.43(1), Unit-cell volume = 594.26(8) A3;Density of Lii.6AICl3.4So.6= 1.984 g cm-3RwP= 2.85 %, Space group P2i / cImpurity phases: 14 wt% of Li2S and 10 wt% of Li1.66S0.66CI0.34Name Atom Wycoff Atomic coordinates Occupancy UiS0p rosition - x y zLi1 Li 4e 0.198(1) 0. 035(1) 0.349(6) 1 0.14(4)Li2 Li 2a 0 0 0 1(4) 0.08(2)Li3 Li 2a 0.5 0 0.5 0.17(3) 0.59(7)AI2 Al 4e 0.728(2) 0.335(2) 0.898(1) 1 0.057(3)CI1 Cl 4e 0.685(2) 0.200(2) 0.043(1) 1 0.025(5)CI2 Cl 4e 0.955(2) 0.164(2) 0.809(1) 1 0.032(3)CI3 Cl 4e 0.812(2) 0.622(1) 0.925(1) 1 0.032(3)CI4 Cl 4e 0.464(2) 0.296(2) 0.806(1) 0.519(6) 0.065(6)S4 S 4e 0.464(2) 0.296(2) 0.806(1) 0.481(6) 0.065(6)TH 930603-2120FSU 23-071 PRCWOTable 13. Rietveld-refinement results of the Lii 66So66Clo34-phase present in IJ2AICI3S.Refined composition: Li1.66S0.66CI034Lattice parameter: a = 5.7138(7), a - b - g = 90.0000,Unit-cell volume = 186.64(5) A3;Density of Li1.66S0.66CI0.34 = 1.592 g / cm3Space group Fm-3mName Atom Wycoff Atomic coordinates Occupancy UiS0position - x y zLi Li 8c 0.25 0.25 0.25 0.83(1) 0.015(5)S S 4a 0 0 0 0.66(1) 0.012(1)Cl Cl 4a 0 0 0 0.34(2) 0.012(2)

[0174] To understand the local structures of LiAIC and Li16AICI34S06,6Li MAS NMR experiments were performed. As shown in Figure 17, the6Li MAS NMR spectrum of LiAICL reveals a major resonance at -0.92 ppm assigned to octahedrally coordinated Li 1 . This is consistent with findings from a previous study.7In addition, a minor resonance at -1.08 ppm is assigned to LiCI.24After incorporating S2’ in the parent material, the6Li NMR spectra of Li1.6AICI3.4S06 is characterized by five distinct resonances at -0.89, -1.24, -0.07, 1.48, and 2.21 ppm - indicating changes in the local Li environment. The minor peak observed at 2.21 ppm corresponds to the Li2S impurity.25The phase quantification is given in Table 14. The resonances at -0.89, -1.24, and -0.07 ppm are assigned to the octahedrally coordinated Li1 , Li2, and Li3 sites, respectively - in agreement with the results from structural refinement. In addition, there is an extra peak at 1.48 ppm, likely from the Li1.66S0.66CI0.34 phase identified with the Rietveld refinement of the high-resolution diffraction pattern.Table 14. Li (%) distribution in various components in LiAICU and Li1.6AICI3.4S06 from6Li NMR analysis.Sample6Li (%)Li 1 Li2 Li3 Li2S LiCI Li1.66S0.66CI0.34LiAICL 92.5 - - - 7.5Li1.6AICI34S06 60.6 31.1 1.3 3.1 - 3.9

[0175] 7Li spin-lattice relaxation time (T1) is a useful indicator of ion dynamics.10,26According to the Bloembergen, Purcell, and Pound (BPP) model, T1 relaxation time is a function of motional rate (TC) , where y is the gyromagnetic ratio, i is the reducedPlanck’s constant, r0is the interatomic distance, ooo= yB0is the Larmor frequency, and Bois the external magnetic field strength.

[0176] In the fast-motion regime (MOTC« 1), T1 increases with increasing motional rate, while in the slow-motion regime (<DOTC» 1), T1 decreases with increasing motional rate. In addition, a resonance can lie in the intermediate region where a>0Tc== 1.27Variable-temperature7Li NMR T1 relaxation data of Li1.6AICI34S06 reveals a decrease in T1 relaxation time with increasing temperature and, thus, suggesting Li+dynamics in Li1.6AICI3.4S06 lie in the slow-motion regime(0Tc» 1). Therefore, a shorter Ti value will correlate with faster ion mobility. As presented in Table 15, the7Li Ti relaxation time significantly decreases from LiAICU to Li16AICI3.4S06, suggesting enhanced Li+mobility28with sulfur incorporation.Table 15.7Li spin-lattice relaxation time (Ti) of LiAICU and Li1.6AICI3.4S06Sample7Li Ti [s]LiAICU 5.2Li1.6AICI3.4S06 3.1

[0179] Ion Transport Pathways Determined by Tracer-Exchange NMR

[0180] To directly probe the Li+transport pathways in Li1.6AICI34S06, tracer-exchange NMR is employed.32By identifying and quantifying6Li+a7Li+exchange under an applied biased potential, the preferential pathway utilized by Li+ions for migration is directly mapped out - facilitating the identification of active sites for Li+transport.29-32The experimental configuration involves sandwiching Li1.6AICI3.4S06 pellet between two6Li foils. An externally applied potential gradient establishes a driving force for6Li+ions in the6Li foils to move toward and exchange with7Li+in the Li1.6AICI34S06 pellet. Consequently, the preferential Li+transport pathways are selectively enriched with6Li+ions. The6Li NMR spectra reveal changes in the relative intensities of resonances assigned to distinct Li+environments. Notably, a significant increase in the intensity of the Li1 and Li2 resonances is observed, suggesting the major involvement of Li1 and Li2 in ion conduction. In addition, the Li3 resonance shows a small intensity enhancement after cycling. The enhancement of these resonances suggests that Li 1 , Li2, and Li3 all participate in Li+-ion transport within the Li16AICI3.4S06 solid electrolyte.

[0181] AIMD simulations

[0182] To further understand the effect of Cl-S anion mixing on the Li+density distribution and diffusion, AIMD simulations are employed for LiAICU and Li16AICI34S06 in a 2 x 2 x 1 cell. The mean square displacements (MSD) of Li+(Figures 18a & b) and distribution probability (Figure 18c & d) for Li at 900 K were calculated. The MSD plots demonstrate that Li+can diffuse in all three directions, with higher diffusion observed along the b direction in LiAICk However, with Cl- S anion mixing, Li+diffusion along the a and c directions increases significantly, resulting incomparable MSDs in all three directions in Li16AICI34S06. This transformation indicates that Li1.6AICI3.4S06 is a 3D ion conductor with a uniform ion transport network in all three dimensions. Furthermore, the overall MSD of Li+shows a 50% increase upon Cl-S anion diversification compared to LiAICU The AIMD simulation of Li+trajectories (i.e. , Li+probability density) in LiAICU shows a localized “cage-like” Li+diffusion pattern with few interstitial jumps, indicating limited long- range Li+migration. In comparison, Li1.6AICI3.4S06 exhibits a delocalized Li+diffusion network, suggesting improved macroscopic Li+migration and, consequently, enhanced Li+conduction in Li1.6AICI3.4S0.6-

[0183] Electrochemical Properties

[0184] To examine ion transport properties of all prepared SEs, variable- temperature electrochemical impedance spectroscopy (EIS) was employed, and the corresponding Nyquist plots at 25 °C are presented in Figure 19a with a corresponding exemplary equivalent circuit fitting shown in Figure 19b. The results from the EIS analysis are given in Table 16. Based on fitted resistances from the Nyquist plot using equivalent circuit modeling, the conductivities of LiAICU and Li1.6AICI3.4S06 are 0.008 mS cm-1and 0.18 mS cm-1, respectively. (Figure 19a). To confirm the conductivities are due to ionic transport, the DC polarization measurements23were performed, and the plots for LiAICU and Li1.6AICI3.4S06 are shown in Figure 19c. The current value upon plateauing corresponds to electronic conductivities of 3.49 x 10'8S cm-1and 5.43 x 10'8S cm-1for LiAICU and Li1.6AICI3.4S06, respectively, thereby confirming negligible electronic contribution to the measured total conductivities of the samples. The ionic conductivity of Li1.6AICI3.4S06 is approximately twenty-fold greater than LiAICU at room temperature. The significant increase in ionic conductivity of Li1.6AICI3.4S06 can be attributed to the local disorder and “Li-stuffing” of the Li3-octahedra that connect with neighboring Li1 / Li2 octahedra and the substitution of Cl with more polarizable S anions. The energy barrier for Li-ion transport (Ea) was calculated from the variabletemperature EIS measurements between 0 °C to 70 °C. The Arrhenius-type plot of LiAICU and Li1.6AICI3.4S06 are shown in Figure 19d. A decrease in Eafrom 0.51 eV to 0.44 eV is observed from LiAICU to Li1.6AICI3.4S06. This decrease in activation energy correlates with the increase in ionic conductivity.33This trend agrees with the energy barrier obtained from the Bond Valence Site Energy (BVSE) calculation.Table 16. DC ionic conductivity at 25 °C, electronic conductivity at 25 °C, activation energy, and Arrhenius prefactor of LiAICU and Li1.6AICI3.4S06.Composition ODC, 25 °C oe, 25 ”c EaLog(oo)[S cm’1] [S cm’1] [eV] [S cm’1K]LiAICL 8.65 x IO’63.49 x W80.51 6.55Li1.6AICI3.4S06 1.80 x IO45.43 x IQ80.44 6.07

[0185] Cyclic Voltammetry and Galvanostatic Cycling of ASSB Half-cells

[0186] Conventionally, CV measurements were done using stainless steel as the blocking electrode, which fails to accurately measure the oxidation and reduction current of SEs due to the limited electrical contact area of the SE and the planar ion-blocking electrode.1034To overcome this and estimate the oxidation-reduction reactions of the SE, we performed CV utilizing a 3SE:C (mass ratio) composite cathode in the Li-I n|SE| 3SE:C half-cell setup, according to the literature.35-37In this setup, carbon serves as an electronic conductive medium in the composite cathode, enabling increased SE surface area in electrical contact with the electrode and consequential detection of degradation current.10'1634-36 38-40Figure 20 shows the voltammograms of Li1.6AICI3.4S06 with a scanning window of 0 - 4 V vs. Li-ln. The first cathodic peak starts at the voltage of 1.04 V vs. Li-ln. This voltage is assigned to the electrolyte reduction to form U2S and AICI3.10,16,41The CV for Li1.6AICI3.4S06 indicates the onset oxidation voltage of 2.4 V vs. Li-ln. This is reasonable as most of the reported sulfide solid electrolytes have a lower stability window than halides (LiAICL).42,43So, the electrochemical stability window of the prepared Li1.6AICI3.4S06 is in the range of 1 .04 - 2.41 V vs. Li-ln, corresponding to the 1 .64 - 3.01 V vs Li / Li+.

[0187] Titanium disulfide (TiS2) was employed as the cathode active material (CAM) in the halfcell configurations for electrochemical evaluation. Li-ln|Li6PS5CI|2(LIAICl4):TiS2 and Li-InlLiePSsCI |2(Lii.6AICl3.4So.6):TiS2 cells were fabricated according to previous studies.10’16A Li-ln anode was employed for enhanced stability against SEs and reduced dendrite formation through micropores - reducing the risk of short circuits.44LiePSoCI was utilized as the separator due to its high ionic conductivity and stability against Li metal. The electrochemical performance of these half-cells was assessed through a series of rate capability tests, spanning charging / discharging currents from 0.1C to 2C conducted under galvanostatic conditions at ~22 °C. Each rate was applied over five cycles (0.1 C ~ 0.14 mA cm-2, 0.2 C ~ 0.28 mA cm-2, 0.5 C ~ 0.70 mA cm-2, 1 C ~ 1.40 mAcm-2, and 2 C ~ 2.80 mA cm-2) followed by 125 cycles at 0.2 C. A theoretical capacity of 239 mAh g-1for TiS2 was used to calculate the charge-discharge rates.

[0188] Figure 21a illustrates the variation in specific capacity with cycle number for the half-cell configurations, while Figures 21b,c display the voltage profiles for select cycles. Initially, the cell incorporating LiAICU demonstrated a discharge capacity of approximately 273 mAh g-1and a charge capacity of 213 mAh g-1, whereas the Lii 6AICl34So6-containing cell exhibited a comparable initial discharge capacity of 272 mAh g-1and a higher charge capacity of 248 mAh g-1(Figure 21a, b). Upon the second discharge, the capacity for the LiAICL-based cell declined to 208 mAh g-1, whereas the Lii.6AICl3.4So.6-based cell showed a reduced yet more stable capacity of 240 mAh g-1, eventually stabilizing around 239 mAh g-1(Figure 21a, b). This is likely due to the formation of a stable solid-electrolyte interface (SEI) during the first cycle. The lower capacity observed in the LiAICL-based cell is primarily due to its low ionic conductivity of the solid electrolyte (SE), which restricts the efficient utilization of the active material - leading to a lower capacity.45Interestingly, initial capacities recorded for both cells surpassed the theoretical capacity of TiS2, (239 mAh g-1). This is attributable to the unidentified reversible redox behavior of the SE in addition to the Ti3+ / 4+redox (Figures 22a-b).46’47

[0189] The Lii 6AICl34So6-containing cell exhibited a capacity of 180 mAh g-1even at a high discharge rate of 2C, indicative of exceptional rate performance in contrast to the significantly reduced capacity of 37 mAh g-1observed at a similar rate for the LiAICL-based cells. Upon returning to 0.2C after 26 cycles, both cell configurations demonstrated remarkable stability over 200 cycles. Furthermore, these cells maintained a high coulombic efficiency exceeding 99% throughout this extended cycle period (Figure 21a). Between the 27th and 200th cycles, the Lii 6AICl34So 6-based cell demonstrated a capacity retention of approximately 90%, whereas the LiAICU-based cell exhibited a faster degradation rate. The superior performance of the Li- ln|Li6PS5CI|2(Lii.6AICl3.4So.6):TiS2 cell is attributed to the synergistic benefits of enhanced ionic conductivity, electrochemical stability, and improved utilization of cathode active materials.70

[0190] Conclusion

[0191] Developing inexpensive SEs using earth-abundant elements is imperative to reduce the cost of ASSBs for widespread applications in electric vehicles and consumer electronics. In this work, we synthesized a new lithium chalcohalide solid electrolyte, Li1.6AICI3.4S06, with a roomtemperature ionic conductivity of 0.18 mS cm-1. Structural characterization reveals that theenhanced ionic conductivity of Li 16AICI34S06 strongly correlates with the formation of face- and edge-sharing octahedrally coordinated lithium sites. The face- and edge-shared octahedra create low-energy conduction pathways that promote 3D Li+conduction, further confirmed by AIMD simulations using the refined structures.67Li MAS NMR combined with tracer exchange and relaxometry reveals increased ion mobility and participation of all Li+sites in ion conduction. Li1.6AICI3.4S06 demonstrates good long-term cycling stability and rate performance in ASSBs, achieving a specific capacity of 180 mAh g'1at a fast charging rate of 2C in a Li- ln|Li6PS5CI|2(Lii.6AICl3.4So.6):TiS2 battery cell, compared to 37 mAh g-1in the LiAICL-containing cell. The cost-effectiveness, combined with the demonstrated high performance, makes Li1.6AICI3.4S06 an excellent candidate as electrolytes for ASSBs.

[0192] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the abovedescribed embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.REFERENCES FOR EXAMPLE 1(1) Flores-Gonzalez, N.; Minafra, N.; Dewaid, G.; Reardon, H.; Smith, R. I.; Adams, S.; Zeier, W. G.; Gregory, D. H. Mechanochemical Synthesis and Structure of Lithium Tetrahaloaluminates, LiAIX 4 (X = Cl, Br, I): A Family of Li-Ion Conducting Ternary Halides. ACS Materials Lett. 2021 ,3 (5), 652-657. https: / / doi.org / 10.1021 / acsmaterialslett.1c00055.(2) Scholz, F.; Unkrig, W.; Eiden, P.; Schmidt, M. A.; Garsuch, A.; Krossing, I. 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The Novel Oxy-Sulfide Glassy Ionic Conductors Na4P2S7-XOx 0 < x < 7: Understanding the Features of Static and Dynamic Cations. Solid State Ionics 2023, 402, 116363. https: / / doi.Org / 10.1016 / j.ssi.2023.116363.(17) Olson, M.; Kmiec, S.; Martin, S. W. NaPON Doping of Na4P2S7 Glass and Its Effects on the Structure and Properties of Mixed Oxy-Sulfide-Nitride Phosphate Glass. Inorg. Chem. 2022, 61 (44), 17469-17484. https: / / doi.org / 10.1021 / acs.inorgchem.2c02300.(18) Zhang, Q.; Arnold, W.; Hood, Z. D.; Li, Y.; DeWees, R.; Chi, M.; Chen, Z.; Chen, Y.; Wang,H. Li 0.625 Al 0.125 H 0.25 Cl 0.75 O 0.25 Superionic Conductor with Disordered Rock-Salt Structure. ACS Appl. Energy Mater. 2021, 4 (8), 7674-7680. https: / / doi.Org / 10.1021 / acsaem.1 c01011.(19) Ohno, S.; Rosenbach, C.; Dewaid, G. F.; Janek, J.; Zeier, W. G. Linking Solid Electrolyte Degradation to Charge Carrier Transport in the Thiophosphate- Based Composite Cathode toward Solid-State Lithium-Sulfur Batteries. 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Claims

CLAIMS1. A compound having the formula AaMbNcXdYeSf, whereinA is Li, Na , K, or any combination thereof;M is Al, Ga, In, or any combination thereof;N is Mg, Ca, Zn, or any combination thereof;X and Y are, independently, F, Cl, Br, or I;S is sulfur; a is from about 1 to about 4; b is from about 0.5 to about 5.0; c is greater than or equal to 0 to about 1.5; d is from about 1 to about 5; e is greater than or equal to 0 to about 3; f is greater than 0 to about 3; and the sum (a + 3b + 2c) is equal to the sum (d + e + 2f).

2. The compound of claim 1 , wherein A is Li.

3. The compound of claim 1 , wherein A is Na.

4. The compound of claim 1 , wherein a is from about 1 to about 2.

5. The compound of claim 1 , wherein M is Al.

6. The compound of claim 1 , wherein M is Ga.

7. The compound of claim 1 , wherein M is In.

8. The compound of claim 1 , wherein b is from about 0.5 to about 1.0.

9. The compound of claim 1 , wherein N is Ca.

10. The compound of claim 1 , wherein N is Zn.

11. The compound of claim 1 , wherein c is zero.

12. The compound of claim 1 , wherein c is from about 0.1 to about 1.0.

13. The compound of claim 1 , wherein X is Cl14. The compound of claim 13, wherein d is from about 2 to about 4.

15. The compound of claim 1 , wherein when e is greater than zero, Y is Br.

16. The compound of claim 15, wherein e is greater than zero to about 1.

17. The compound of claim 1, wherein A is Li or Na, M is Al, and X is Cl.

18. The compound of claim 1, wherein A is Li, M is Al and Ga, X is Cl, and Y is F.

19. The compound of claim 1, where the compound has the formula AaAlbCldSf, wherein A isLi or Na.

20. The compound of claim 19, wherein a is from about 2 to about 4, b is from about 0.5 to about 1.0, d is from about 2 to about 4, and f is from about 1 to about 3.

21. The compound of claim 1, wherein the compound has the formula LiaAlbNcCldSf, wherein N is Ca or Zn.

22. The compound of claim 21 , wherein a is from about 1 or to about 2, b is from about 0.5 to about 1.0, c is from about 0.1 to about 1.0, d is from about 2 to about 4, and f is from about 1 to about 3.

23. The compound of claim 1, where the compound has the formula LiaAlbCldBreSf.

24. The compound of claim 23, wherein a is from about 1 or to about 2, b is from about 0.5 to about 1 , d is from about 2 to about 4, e is greater than zero to about 1 , and f is from about 1 to about 3.

25. The compound of claim 1, wherein the compound has the formula U2AICI3S, U4AICI3S2, Na2AICI3S, or K2AICI3S.

26. The compound of claim 1, wherein the compound has the formula Li2AlbiGab2CldFeS, wherein (b1 + b2) - b.

27. The compound of claim 26, wherein b1 is from about 0.5 to about 0.9, b2 is from about 0.1 to about 0.5, d is from about 2.1 to about 2.9, and e is from about 0.1 to about 0.9.

28. The compound of claim 1, wherein the compound has the formula LiaAICI Sf, wherein a is from about 1.0 to about 2.0, d is from about 3.0 to about 4.0, and f is from about 0.1 to about 1.0.

29. The compound of claim 1, wherein the compound has the formula Li2AI0.9Ga0.1CI2.7F0.3S, Li2AI03Ga0.2CI24F0.6S, Li2AI0.7Ga0.3CI2.1F0.9S, or Li1.6AICI3.4S0.6-30. The compound of claim 1, wherein the compound has an ionic conductivity of at least 0.10 mS / cm.

31. The compound of claim 1, wherein the compound has an ionic conductivity of at least 0.10 mS / cm to about 1.00 mS / cm.

32. The compound of claim 1, wherein the compound has an electronic conductivity less than 1.00 x 10'7S / cm.

33. The compound of claim 1, wherein the compound has an electronic conductivity of about 1.00 x 10“7S / cm to about 1.00 x 10'10S / cm.

34. The compound of claim 1, wherein the compound is conductive over a temperature range of about -20 °C to about 100 °C.

35. The compound of claim 1, wherein the compound has a monoclinic structure type with the space group P2i / c.

36. The compound of claim 1, wherein the compound has an X-ray powder diffraction pattern comprising peaks at 26.9°, 31.2°, and 44.8° ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A.

37. The compound of claim 1 , wherein the compound has an X-ray powder diffraction pattern comprising peaks at 24.6° and 26.9° ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 1.5406 A.

38. The compound of claim 1 , wherein the compound has peaks at about -0.98 ppm, 0.15 ppm, and 1.60 ppm, as determined by6Li solid-state NMR spectroscopy.

39. The compound of claim 1, wherein the compound has an orthorhombic structure type with the space group P2i2i2i.

40. The compound of claim 1 , wherein the compound has an X-ray powder diffraction pattern comprising peaks at 23.5° and 38.9° ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 0.24 A.

41. The compound of claim 1 , wherein the compound has a peak at about 42.66 ppm, as determined by23Na solid-state NMR spectroscopy.

42. The compound of claim 1, wherein the compound has a cubic structure type with the space group Fm-3m.

43. The compound of claim 1, wherein the compound has an X-ray powder diffraction pattern comprising peaks at 28.4° and 40.6° ± 0.2° 20 as measured by X-ray powder diffraction using an X-ray wavelength of 0.24 A.

44. The compound of claim 1, wherein the compound has a capacity of about 150 mAh / g to about 200 mAh / g at a discharge rate of 2C.

45. A method for making a compound having the formula AaMbNcXdYeSf, whereinA is Li, Na, K, or any combination thereof;M is Al, Ga, In, or any combination thereof;N is Mg, Ca, Zn, or any combination thereof;X and Y are, independently, F, Cl, Br, or I;S is sulfur; a is from about 1 to about 4; b is from about 0.5 to about 5.0; c is greater than or equal to 0 to about 1.5; d is from about 1 to about 5; e is greater than or equal to 0 to about 3; f is greater than 0 to about 3; and the sum (a + 3b + 2c) is equal to the sum (d + e + 2f), the method comprising: mixing in the solid state the following components: (i) A2S; (ii) AX, AY, or a combination thereof; (iii) MX3, MY3, or a combination thereof; and (iv) NX2, NY2, or a combination thereof to produce a first mixture.

46. The method of claim 45, wherein the components are substantially anhydrous.

47. The method of claim 45, wherein the components are mixed by mechanochemical milling.

48. The method of claim 45, wherein the components are mixed in an inert atmosphere.

49. A compound produced by the method of claim 45.

50. A battery comprising the compound in any one of claims 1-44 or 49.

51. The battery of claim 50, wherein the battery is a solid-state battery.

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