Thiophilic metal-doped argyrodites

Abstract

To provide a solid material having ion conductivity and an electrochemically stable composition, a manufacturing method of the material, and a battery and a battery component including the material.SOLUTION: The solid material is an argyrodite-type composition (Li6PS5Cl) that has high ionic conductivity and is easy to process, and contains small amounts of thiophilic metals (compositions selected from Mn, Fe, Co, Ni, Cu, Zn, Hg, Mo and combinations thereof), but whose binary sulfides do not react with water to form hydrogen sulfide (H2S). As such, the release of H2S is minimized or eliminated.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] [Incorporated by reference] The PCT Request Form is being filed contemporaneously herewith as part of this application. Each application to which this application claims benefit or priority, as identified in the contemporaneously filed PCT Request Form, is incorporated herein by reference in its entirety and for all purposes.

[0002] Solid electrolytes offer various advantages over liquid electrolytes for secondary batteries. For example, in lithium-ion batteries, inorganic solid electrolytes may be less flammable than traditional liquid organic electrolytes. Solid electrolytes can also facilitate the use of lithium metal electrodes by suppressing dendrite formation. However, the use of solid electrolytes presents challenges, such as low conductivity and poor electrochemical stability. Summary of the Invention

[0003] Provided herein are solid-state materials that are ionically conductive and electrochemically stable. An embodiment of such a solid-state material is an argyrodite-type composition with high ionic conductivity. This composition contains a small amount of a thiophilic metal, but its binary sulfide does not react with water to form hydrogen sulfide (HS). Therefore, HS emissions are minimized or eliminated. Also provided are methods for producing this material, as well as batteries and battery components containing this material.

[0004] One aspect of the present disclosure relates to a composition comprising an alkali metal argyrodite sulfide-based ionic conductor doped with a thiophilic metal. The thiophilic metal can be selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), molybdenum (Mo), and combinations thereof. According to various embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:120. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:50.

[0005] In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is less than or equal to 1:1. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is less than or equal to 1:4.

[0006] In some embodiments, the alkali metal is one of lithium (Li), sodium (Na), or potassium (K). In some embodiments, the alkali metal is lithium. In some embodiments, the alkali metal argyrodite sulfide-based ionic conductor has the formula: A 7-x-(z*y) M z y PS 6-x Hal x wherein A is an alkali metal, M is a thiophilic metal, and Hal is selected from chlorine (Cl), bromine (Br), and iodine (I); z is the oxidation state of the metal, 0 <x≦2、および 0 <y<(7-x) / zである。

[0007] In some embodiments, z > +1. In some embodiments, z = +2. In some embodiments, 1 < x < 1.6. In some embodiments, 0.1 < y < 2 - x. In some embodiments, the alkali metal argyrodite sulfide based ionic conductor has the formula: A 7-x+n-(z*y) M z y PS 6-x Hal x+n wherein A is an alkali metal, M is a thiophilic metal, and Hal is selected from chlorine (Cl), bromine (Br), and iodine (I); z is the oxidation state of the metal, 0.05≦n≦0.9, -3.0x+1.8≦n≦-3.0x+5.7, 0≦y<(7-x) / z, and 0 <x≦2である。

[0008] In some embodiments, z>+1. In some embodiments, z=+2. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:120. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:50. In some embodiments, the alkali metal argyrodite sulfide-based ionic conductor is a single-phase material.

[0009] Another aspect relates to a composite membrane of particles comprising thiophilic metal-doped argyrodite in a polymer. The argyrodite can be any thiophilic metal-doped argyrodite sulfide-based ionic conductor, as described herein. In some embodiments, the polymer is a hydrophobic polymer. In some embodiments, the polymer is not ionically conductive. In some embodiments, the polymer is styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR).

[0010] In some embodiments, the polymer is a copolymer having a plastic copolymer segment and an elastic copolymer segment, and in some embodiments, the composite membrane comprises 0.5% to 60% by weight of the polymer, 1% to 40% by weight of the polymer, or 5% to 30% by weight of the polymer.

[0011] Another aspect of the present disclosure relates to a slurry, paste, or solution having one or more solvents, a polymer, and ion-conducting particles comprising the thiophilic metal-doped argyrodite described herein. In some embodiments, the polymer is a hydrophobic polymer. In some embodiments, the polymer is not ion-conducting. In some embodiments, the polymer is styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR). In some embodiments, the polymer is a copolymer having a plastic copolymer segment and an elastic copolymer segment.

[0012] Another aspect of the present disclosure relates to a composition comprising a transition metal oxide active material, a thiophilic metal-doped argyrodite as described herein, and an organic polymer. In some embodiments, the polymer is a hydrophobic polymer. In some embodiments, the polymer is not ionically conductive. In some embodiments, the polymer is styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR). In some embodiments, the polymer is a copolymer having a plastic copolymer segment and an elastic copolymer segment. In some embodiments, the composition further comprises a conductive additive. A battery can be provided comprising the composition and a mesh current collector embedded in the composition.

[0013] Another aspect of the present disclosure relates to a composition comprising a silicon-containing active material, a graphite-based active material, a thiophilic metal-doped argyrodite described herein, and an organic polymer. In some embodiments, the polymer is a hydrophobic polymer. In some embodiments, the polymer is not ionically conductive. In some embodiments, the polymer is styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR). In some embodiments, the polymer is a copolymer having a plastic copolymer segment and an elastic copolymer segment. In some embodiments, the composition further comprises a conductive additive. In these or other embodiments, the argyrodite may be represented according to Formula I or Formula II. A battery may be provided comprising the composition and a mesh current collector embedded in the composition.

[0014] These and other aspects are further described below with reference to the figures. [Brief explanation of the drawings]

[0015] [Figure 1] The cubic crystal structure of argyrodite-type Li6PS5Cl is shown.

[0016] [Figure 2] FIG. 1 is a process flow diagram illustrating certain operations in a method for forming a composite membrane.

[0017] [Figure 3] FIG. 1 is a process flow diagram illustrating certain operations in a method for making a composite electrolyte.

[0018] [Figure 4] FIG. 1 is a process flow diagram illustrating certain operations in a method for forming a composite using liquid phase assisted sintering.

[0019] [Figure 5A] 1 shows an example of a schematic diagram of a cell containing an argyrodite-containing composition doped with a thiophilic metal. [Figure 5B] 1 shows an example of a schematic diagram of a cell containing an argyrodite-containing composition doped with a thiophilic metal. [Figure 5C] 1 shows an example of a schematic diagram of a cell containing an argyrodite-containing composition doped with a thiophilic metal.

[0020] [Figure 6] Powder diffraction pattern of Cu-doped argyrodite Li5.4Cu0.1PS4.6Cl1.4 with overlaid reference lines from argyrodite Li6PS5Cl.

[0021] [Figure 7] Powder diffraction pattern of Cu-doped argyrodite Li5.8Cu0.1PS5Cl with overlaid reference lines from argyrodite Li6PS5Cl.

[0022] [Figure 8] 1 is a graph showing the amount of H2S released from argyrodite sulfide-based ionic conductors and their compounds doped with various thiophilic metals. DETAILED DESCRIPTION OF THE INVENTION

[0023] Provided herein are solid-state materials that are ionically conductive and electrochemically stable. These materials are argyrodite-type compositions that are highly ionically conductive and easy to process. The compositions contain small amounts of thiophilic metals, but the binary sulfides do not react with water to form hydrogen sulfide (HS). Therefore, HS emissions are minimized or eliminated. Also provided are methods for making the materials, as well as batteries and battery components containing the materials.

[0024] [Introduction] The argyrodite mineral, Ag8GeS6, can be thought of as a cocrystal of Ag4GeS4 with two equivalents of Ag2S. This crystal allows substitution in both the cation and the anion while keeping the overall spatial arrangement of the various ions the same. In Li7PS6, PS4 3- The ions are the GeS4 4- It is located in the crystallographic position previously occupied by S 2- The ions retain their original positions, and Li + The ions are the original Ag + Li7PS6 has fewer cations than the original Ag8GeS6, leaving some cation sites empty. These structural analogs of the original argyrodite mineral will also be referred to as argyrodite.

[0025] Both Ag8GeS6 and Li7PS6 are orthorhombic at room temperature, but undergo a phase transition to cubic at elevated temperatures. Further substitution of one equivalent of Li2S with one equivalent of LiCl yields a Li6PS5Cl material, which still retains the argyrodite structure but undergoes an orthorhombic to cubic phase transition below room temperature and possesses significantly higher lithium ion conductivity. The same overall arrangement of cations and anions is maintained in this material, and so it is generally referred to as argyrodite. Therefore, further substitutions that also retain this overall structure may also be referred to as argyrodite. Alkali metal argyrodites are more commonly referred to as argyrodites, where the alkali metal is substituted for Ag within the original argyrodite structure. + Any of a class of conductive crystals that occupy sites and retain the spatial arrangement of anions found in the parent mineral.

[0026] In one example, in the lithium-containing example of this mineral species, Li7PS6, PS4 3- ions in the original mineral GeS4 4- It is located in the crystallographic position previously occupied by S 2- The ions retain their original positions, and Li + The ions are the original Ag + Li7PS6 has fewer cations than the original Ag8GeS6, leaving some cation sites empty. As mentioned above, further substitution of one equivalent of Li2S with one equivalent of LiCl results in a Li6PS5Cl material, which still retains the argyrodite structure. Figure 1 shows the cubic argyrodite Li6PS5Cl. In the example of Figure 1, Li + is Ag in argyrodite minerals + Occupying a part, PS4 3- is the original mineral GeS4 4- Occupying the part, S 2- and Cl - The original two S 2- occupies the part.

[0027] There are various ways in which substitutions can be made that preserve the overall structure of argyrodite. For example, the parent mineral can be replaced with two equivalents of S2ー These have O 2- , Se 2- , Te 2- It can be substituted with chalcogen ions such as S 2- A significant portion of can be substituted with halogen. For example, two equivalents of S 2- About 1.6 of these are Cl - , Br - and I - can be substituted with Cl, the exact amount depending on the other ions in the system. - is S 2- It is similar in size to S, but has one charge instead of two, and its binding and reactivity are substantially different. Other substitutions may be made, and in some cases, e.g., S 2- Part of the - ) and the rest is Se 2- Similarly, GeS4 3- Various substitutions may be made at the GeS4 site. 3- Instead of PS4 3- may be replaced by PO4 3- , PSe4 3- , SiS4 3- These are all tetrahedral ions with four chalcogen atoms, and as a whole they are S 2- They are larger and have three or four charges.

[0028] In other examples, compared to the Li6PS5Cl argyrodite-type structure described above, Li6PS5Br and Li6PS5I substitute larger halides for chloride, e.g., Li6PO5Br for Li6PO5Cl. Z. Anorg. Allg. Chem., 2010, 636, 1920-1924, is incorporated herein by reference for purposes of describing specific argyrodites, e.g., S 2- and PS4 3- Both ions exchange all sulfur atoms in the structure for oxygen, as well as containing the described halide substitutions. 3-The phosphorus atoms in the ions can be partially or totally substituted, e.g., Li 7+x M x P 1-x The S6 (M=Si, Ge) series forms argyrodite-type structures over a wide range of x. See J. Mater. Chem. A, 2019, no. 7, 2717-2722, which is incorporated herein by reference for purposes of describing specific argyrodites. P substitution can also be carried out incorporating halogens. For example, Li 6+x Si x P 1-x S5Br is stable from x=0 to about 0.5. See J. Mater. Chem. A, 2017, no. 6, 645-651, which is incorporated herein by reference for purposes of describing specific argyrodites. PS4 3- Instead of SbS4 3- and MS4 4- is replaced by a mixture of Cl - instead of I - Li using 7+x M x Sb 1-x Compounds based on S6 (M = Si, Ge, Sn) have been prepared and found to form argyrodite-type structures. See J. Am. Chem. Soc., 2019, no. 141, pp. 19002-19013, which is incorporated herein by reference for purposes of describing specific argyrodites. It is also possible to substitute other cations in addition to lithium (or silver) at the cation site. Examples include Cu6PS5Cl, Cu6PS5Br, Cu6PS5I, Cu6AsS5Br, Cu6AsS5I, and Cu. 7.82 SiS 5.82 Br 0.18 , Cu7SiS5I, Cu 7.49 SiS 5.49 I 0.51 , Cu 7.44 SiSe 5.44 I 0.56 , Cu 7.75 GeS 5.75 Br 0.25 , Cu7GeS5I, and Cu 7.52 GeSe 5.52 I 0.48All of these have been synthesized and have the argyrodite-type crystal structure. See Z. Kristallogr, 2005, no. 220, 281-294, which is incorporated herein by reference for purposes of describing specific argyrodites. These examples demonstrate that not only are single element substitutions possible in any of the various portions of the argyrodite-type structure, but that combinations of substitutions often result in the argyrodite-type structure. These include the argyrodites described in U.S. Patent Publication No. 20170352916, which are Li ions, where x and y satisfy the formulas 0.05≦y≦0.9 and −3.0x+1.8≦y≦−3.0x+5.7. 7-x+y PS 6-x Cl x+y Includes.

[0029] The argyrodites described herein are those in which a substantial (at least 20%, often at least 50%) portion of the anions are sulfur (e.g., S 2- and PS4 3- ) is a sulfide-based ionic conductor containing lithium argyrodite. + These materials have demonstrated high mobilities and are of interest as materials for lithium batteries. As mentioned above, one example of a material in this family is Li6PS5Cl, a ternary co-crystal of Li3PS4, Li2S, and LiCl. Various embodiments of argyrodites described herein have thiophilic metals that can occupy lithium cation sites in the argyrodite crystal structure. In the argyrodite shown in Figure 1, each cation is a PS4 3- Two sulfur atoms in the anion, one S 2- The thiophilic metal is coordinated to a sulfur anion and two chloride anions. The thiophilic metal occupies some of these lithium cation sites. The thiophilic metal may be used to dope other alkali metal argyrodites as well.

[0030] In certain embodiments, multiple Li cations are replaced with thiophilic cations, which reduces the otherwise soluble fraction of the Li cations that would otherwise be present in the aqueous solution due to atmospheric moisture and S 2-In idealized or near-ideal structures such as those shown in Figure 1, each thiophilic cation site contains one S 2- However, in halogen-containing argyrodites, the sulfur and halogen sites show significant disorder, and the thiophilic dopant atom is substituted with one, two, or three S 2- It can be positioned at the center.

[0031] Suppression of hydrogen disulfide is advantageous as it is toxic and flammable, and prevents a particularly serious hazard in device failure modes where the casing may open, exposing the end user.

[0032] [Composition] Provided herein is an alkali metal argyrodite sulfide-based ionic conductor doped with a thiophilic metal. The thiophilic metal may be manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), and molybdenum (Mo), or a combination thereof. In alternative embodiments, other thiophilic elements may be used. The amount of thiophilic metal may be controlled to limit hydrogen sulfide while maintaining ionic conductivity. Too little thiophilic metal may result in high hydrogen sulfide generation. Too much thiophilic metal may result in reduced ionic conductivity. In some embodiments, the doping amount is characterized by the ratio of thiophilic metal atoms to sulfur atoms in the argyrodite. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal sulfide-based ionic conductor is at least 1:120. In some embodiments, it is at least 1:50. In some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is 1:1 or less, and in some embodiments, the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is 1:4 or less. In some embodiments, a ratio of 1:20 may result in more than sufficient hydrogen sulfide generation and less decrease in ionic conductivity than higher ratios. Examples of ranges of thiophilic metal atoms to sulfur atoms include 1:120 to 1:1, 1:120 to 1:4, 1:120 to 1:20, 1:50 to 1:1, 1:50 to 1:4, and 1:50 to 1:20. (Note: S 2- Coordination with anions prevents the generation of hydrogen sulfide, but the above ratios are relative to the total sulfur atoms in argyrodite.

[0033] The upper limit of the dopant atoms in the thiophilic metal depends on the oxidation state, and a 1:1 ratio can be achieved only in the +1 oxidation state. Such argyrodites include, for example, LiCu5PS5Cl, Li 1.1 Cu 5.9PS 5.9 C l0 At a ratio of 1:4, for example, Li 3.5 Cu 1.25 PS5Cl, Li 3.5 Ni 1.25 PS5Cl (+2 oxidation state), and Li 3.5 Fe 0.833 Examples include PS5Cl (+3 oxidation state).

[0034] Doping can alternatively be characterized as the mole percent of thiophilic atoms relative to sulfur atoms. In some embodiments, the argyrodite contains at least 0.83 mole percent of thiophilic metal atoms relative to sulfur atoms. In some embodiments, the argyrodite contains at least 2 mole percent of thiophilic metal atoms relative to sulfur atoms. An argyrodite containing 2 mole percent Cu relative to sulfur (Li 5.8 Cu 0.1 A significant hydrogen sulfide suppression effect was measured with PS5Cl. In some embodiments, the argyrodite contains up to 5 mole percent thiophilic metal atoms relative to sulfur atoms. This range includes, for example, 0.8-5 mole percent thiophilic metal atoms relative to sulfur atoms, and 0.8-2 mole percent thiophilic metal atoms relative to sulfur atoms.

[0035] The thiophilic metal-doped argyrodites described herein can be characterized by powder X-ray diffraction (XRD) showing that a significant portion of the sample has the argyrodite-type structure, and elemental analysis techniques such as ICP-MS and ICP-AES can be used to determine the identity of the doped metal(s) and the metal / sulfur molar ratio.

[0036] In some embodiments, the alkali metal argyrodite sulfide-based ionic conductor is according to Formula I: A 7-x-(z*y) M z y PS 6-x Hal x (Formula I) wherein A is an alkali metal, M is a metal selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), and molybdenum (Mo), and Hal is selected from chlorine (Cl), bromine (Br), and iodine (I); z is the oxidation state of the metal, 0 <x≦2、および 0 <y<(7-x) / zである。

[0037] The oxidation state depends on the metal dopant. According to various embodiments, the following oxidation states may be used: Mn, z=+2, +3, +4, +6, or +7 Fe, z=+2, +3, or +4 Co, z=+2 or +3 Ni, z=+1, +2, +3, or +4 Cu, z=+1 or +2 Zn, z=+2 Hg, z=+1 or +2 Mo, z=+2, +3, +4, +5, or +6

[0038] In some embodiments, the thiophilic metal dopant is incorporated in an oxidation state higher than +1, and in certain embodiments, in the +2 oxidation state. Incorporation in the +1 oxidation state allows the mobility of the incorporated +1 metal to plate into devices such as batteries. For example, plating onto a battery anode can reduce battery capacity, cause unwanted reactions, and nullify the dopant's hydrogen sulfide suppression effect. Higher oxidation states can also reduce the lithium ion concentration in the material, potentially resulting in reduced ionic conductivity.

[0039] The amount of halogen in the argyrodite is determined by x. In some embodiments, 1≦x≦1.6. For x<1, conductivity is generally low at room temperature. At certain values ​​of x<1, depending on the alkali metal and halogen used, the argyrodite-type structure changes to an orthorhombic, low-symmetry crystal structure. Doping with a thiophilic metal stabilizes the cubic structure for x<1, and a step-function decrease in conductivity is not expected. Argyrodites with x>1 are still expected to be advantageous despite this stabilization effect, because they generally have higher conductivity and lower sulfur content. Increasing x above 1 increases conductivity until the argyrodite-type structure becomes unstable near x≧1.6. For x>1.6, argyrodite becomes somewhat unstable, and the composition may become a mixture with other phases, such as lithium sulfide, lithium halide, or lithium thiophosphate. The addition of a metal dopant stabilizes the composition and allows for the use of more halogen.

[0040] The amount of thiophilic metal dopant is characterized by y, where in most practical applications, 0.1≦y≦(2−x) / z; if y is too low, hydrogen sulfide suppression may be insufficient, and if y is too high, ionic conductivity may be undesirably low. Incorporation of thiophilic metals at high concentrations may induce electronic conductivity, which may be undesirable. Compositions according to Formula I may have an M:S ratio of at least 1:120 or at least 1:50. In some embodiments, the M:S ratio is 1:20 or less.

[0041] Compositions of Formula I include those with mixed metals (i.e., the argyrodite is doped with multiple metals) and / or those with mixed halides (i.e., the argyrodite contains two or more of Cl, Br, and I at each halogen site). In the case of mixed halides, Hal x indicates the total amount of halogen, e.g., Br .9 Cl .7In the case of mixed metals, M refers to two or more metals, M1, M2, etc. The oxidation state and concentration of each metal can be different, so for M1, the oxidation state is z1 and the amount of metal present is y1. For M2 metal, the oxidation state is z2 and the concentration is y2, etc. A 7-x-(z*y) M z y PS 6-x Hal x In the case of mixed metals in the equation, the total metal concentration is y = y1 + y2, and the charge z refers to the concentration-weighted average charge of the metals in the system, z = ((z1 * y1)+(z2 * y2)) / (y1+y2).

[0042] As mentioned above, any alkali metal argyrodite sulfide-based ionic conductor can be doped with a thiophilic metal to suppress hydrogen sulfide generation. These can include argyrodites, as described in U.S. Patent No. 20170352916, where x and y satisfy the formulas 0.05≦y≦0.9 and −3.0x+1.8≦y≦−3.0x+5.7, respectively. 7-x+y PS 6-x Cl x+y In some embodiments, the alkali metal argyrodite sulfide-based ionic conductor is represented by the formula: A 7-x+n-(z*y) M z y PS 6-x Hal x+n (Formula II) wherein A is an alkali metal, M is a metal selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), and molybdenum (Mo), and Hal is selected from chlorine (Cl), bromine (Br), and iodine (I); z is the oxidation state of the metal, 0.05≦n≦0.9, -3.0x+1.8≦n≦-3.0x+5.7, 0≦y<(7-x) / z, and 0 <x≦2である。

[0043] The oxidation state depends on the metal dopant. According to various embodiments, the following oxidation states may be used: Mn, z=+2, +3, +4, +6, or +7 Fe, z=+2, +3, or +4 Co, z=+2, or +3 Ni, z=+1, +2, +3, or +4 Cu, z=+1, or +2 Zn, z=+2 Hg, z=+1, or +2 Mo, z=+2, +3, +4, +5, or +6

[0044] In some embodiments, −3.0x+1.8≦n≦−3.0x+5.

[0045] In some embodiments, the thiophilic metal dopant is incorporated in an oxidation state higher than +1, and in particular embodiments, in the +2 oxidation state. Incorporation in the +1 oxidation state can result in metal plating in devices such as batteries due to the mobility of the incorporated +1 metal. For example, plating in a battery anode can reduce battery capacity, cause unwanted reactions, and eliminate the hydrogen sulfide suppression effect of the dopant. Higher oxidation states can also lead to reduced ionic conductivity.

[0046] The amount of thiophilic metal dopant is characterized by y, where in most practical applications, 0.1≦y≦(2−x) / z; if y is too low, hydrogen sulfide suppression may be insufficient, and if y is too high, ionic conductivity may be undesirably low. Incorporation of a thiophilic metal at high concentrations may induce electronic conductivity, which may be undesirable. Compositions according to Formula II may have an M:S ratio of at least 1:120 or at least 1:50. In some embodiments, the M:S ratio is 1:20 or less. Formula II may also include mixed metal and / or mixed halide systems, which are treated as described above for Formula I.

[0047] [Synthesis] Argyrodite can be doped using metal sulfides or metal halides during synthesis. The metal sulfides or metal halides can be mixed with argyrodite precursors such as LiCl, Li2S, and P2S5, or LiCl and Li3PS4 where Hal is Cl. Argyrodite doped with thiophilic metals can be synthesized using one of three main synthetic methods: high-energy ball milling (mechanochemical synthesis), high-temperature solid-state synthesis or thermal synthesis, and solution synthesis.

[0048] High-energy ball milling applies mechanical energy to induce chemical reactions between argyrodite precursors, resulting in the formation of highly amorphous particles. An additional annealing step can be used to enhance the crystallinity and conductivity of the highly amorphous ball-milled argyrodite. The ball-milled argyrodite can be incorporated into fully or partially reacted composites and used before or after annealing.

[0049] In solid-state synthesis, argyrodite reagents are premixed and then thermally reacted to form the argyrodite phase. Unlike ball milling, solid-state reactions are performed at elevated temperatures, close to the annealing temperature, resulting in highly crystalline materials. The reaction can also occur directly in the presence of a polymer; however, high temperatures can lead to polymer decomposition, while low temperatures may be insufficient to fully react the starting materials. Solid-state synthesis can also be carried to completion or stopped to form a mixture of argyrodite with precursors or intermediates. The reaction can be controlled by adjusting the synthesis time and temperature, and such argyrodites can be directly mixed with polymers to form complexes.

[0050] In argyrodite solution synthesis, reactants are mixed in an argyrodite solvent, which allows the complete or partial dissolution of reagents, intermediates, and / or products. This approach uses multi-stage solvent removal to obtain pure argyrodite. First, bulk solvent removal, typically at low temperatures below 100 °C, results in a mixture of argyrodite and argyrodite precursors, which contain starting materials and complex intermediate compounds. Such argyrodite mixtures can be incorporated into composites, and the residual solvent bound to the argyrodite phase can function as a sintering aid during heat treatment. During heat treatment, the residual solvent evaporates, transforming the precursor into the argyrodite phase, while simultaneously promoting sintering of the inorganic particles via liquid-phase sintering. Liquid-phase sintering helps reduce the pressure and temperature requirements for sintering, while simultaneously leading to low porosity and high density. A second removal step of the argyrodite-binding solvent can be performed before incorporation into composites to obtain argyrodite with a degree of crystallinity and crystallite size dependent on the processing temperature and time. Such argyrodites can be incorporated into complexes.

[0051] [Complexes containing argyrodite doped with thiophilic metals] In some embodiments, the thiophilic metal-doped argyrodite may be mixed with a compatible material to form a composite solid ionic conductor. The compatible material may be an organic phase, as described, for example, in U.S. Pat. Nos. 9,926,411 and 9,972,838 and U.S. patent application Ser. No. 16 / 241,784, which are incorporated herein by reference. The organic polymer phase may include one or more types of polymers and is chemically compatible with the ion-conducting inorganic particles. In some embodiments, the organic phase has substantially no ionic conductivity and is referred to as "non-ionically conductive." Non-ionically conductive polymers having ionic conductivities of less than 0.0001 S / cm are described herein.

[0052] In some embodiments, the organic phase includes a polymeric binder, which is a relatively high molecular weight polymer. The polymeric binder has a molecular weight of at least 30 kg / mol, and may be at least 50 kg / mol, or even 100 kg / mol. In some embodiments, the polymeric binder has a non-polar backbone. Examples of non-polar polymeric binders include polymers or copolymers containing styrene, butadiene, isoprene, ethylene, and butylene. Styrenic block copolymers containing polystyrene blocks and rubber blocks may also be used, such as polybutadiene (PBD) and polyisoprene (PI). The rubber blocks may be hydrogenated or unhydrogenated. Specific examples of polymeric binders include styrene-ethylene-butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-butadiene rubber (SBR), polystyrene (PSt), PBD, polyethylene (PE), and PI. Non-polar polymers do not coat the inorganic particles, which can lead to reduced conductivity.

[0053] Lower molecular weight polymers can be used to improve the processability of higher molecular weight polymers, such as SEBS, by, for example, reducing processing temperatures and pressures. These can have molecular weights of, for example, 50 g / mol to 30 kg / mol. Examples include polydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. In some embodiments, the first component is a cyclic olefin polymer (COP), and the first component is a polyalkyl, polyaromatic, or polysiloxane polymer having terminal groups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy, carboxyl, or hydroxyl groups.

[0054] The main chain or backbone of the polymeric component of the organic phase does not interact with the inorganic phase. Examples of backbones include saturated or unsaturated polyalkyls, polyaromatics, and polysiloxanes. Backbones that may interact too strongly with the inorganic phase include those with strong electron-donating groups, such as polyalcohols, polyacids, polyesters, polyethers, polyamines, and polyamides. It is understood that molecules with other moieties that reduce the bond strength of oxygen and other nucleophiles may also be used. For example, the perfluorinated nature of the perfluoropolyether (PFPE) backbone delocalizes the electron density of the ether oxygens, enabling its use in certain embodiments.

[0055] In some embodiments, hydrophobic block copolymers having both plastic and elastic copolymer segments are used, such as styrene-based block copolymers such as SEBS, SBS, SIS, styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), and styrene-ethylene / propylene-styrene (SEPS), and isoprene rubber (IR).

[0056] In some embodiments, the organic phase is substantially non-ionically conductive, and examples of non-ionically conductive polymers include, for example, PDMS, PBD, and other polymers described above. Unlike ionically conductive polymers such as polyethylene oxide (PEO), polypropylene oxide (PPO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA), which exhibit ion conductivity due to the dissolution or dissociation of salts such as LiI, non-ionically conductive polymers do not become ionically conductive in the presence of salt. This is because there are no mobile ions to conduct without dissolving the salt. In some embodiments, one of these or another ionically conductive polymers may be used. PFPE, as described in "Compliant glass-polymer hybrid single ion-conducting electrolytes for lithium ion batteries," PNAS, 52-57, vol. 113, no. 1 (2016), mentioned above and incorporated herein by reference, is ionically conductive and is a single-ion conductor for lithium and may be used in some embodiments.

[0057] In some embodiments, the organic phase may include crosslinking. In some embodiments, the organic phase is a crosslinked polymer network. The crosslinked polymer network can be crosslinked in situ, i.e., after mixing the inorganic particles with a polymer or polymer precursor to form a composite. In situ polymerization of polymers, including in situ crosslinking, is described in U.S. Pat. No. 10,079,404, which is incorporated herein by reference.

[0058] The composite materials described herein can take a variety of forms, including films, slurries or pastes that can be used to make composite films. According to various embodiments, the composite can include any of the following: 1) Argyrodite precursors that do not contain argyrodite, and organic polymers 2) Argyrodite precursors, argyrodites, and organic polymers 3) Argyrodites substantially free of precursors, and organic polymers

[0059] In some embodiments, the composite consists essentially of these components. In some other embodiments, additional components may be present, as further described below. As noted above, in some embodiments, the composite is provided as a solid film. Depending on the particular composition and prior processing, the solid film may be provided in a device without further processing, or may be provided ready for incorporation into a device, or may be provided ready for in-situ processing of the argyrodite as described above. In the latter case, it may be provided as a free-standing film or may be provided ready for incorporation into a processing device.

[0060] The polymer matrix loading in the hybrid composition may be relatively high in some embodiments, e.g., at least 2.5% to 30% by weight. According to various embodiments, the polymer matrix may comprise 0.5% to 60% by weight of polymer, 1% to 40% by weight of polymer, or 5% to 30% by weight of polymer. The composite forms a continuous film.

[0061] The organic polymer is generally a non-polar, hydrophobic polymer as described above. In certain embodiments, it may be a polymer precursor (monomer, oligomer, or polymer) that is also treated in situ for polymerization and / or crosslinking. Such treatment may occur during, before, or after the in situ treatment of the argyrodite.

[0062] In some embodiments, argyrodite and / or its precursors comprise 40% to 95.5% by weight of the membrane. The remainder, in some embodiments, may be an organic polymer. In other embodiments, one or more additional components are present. These can include alkali metal ion salts, including lithium ion salts, sodium ion salts, and potassium ion salts. Examples include LiPF6, LiTFSI, LiBETI, and the like. In some embodiments, the solid composition is substantially free of added salts. "Substantially free of added salts" means that it contains no more than trace amounts of salt. In some embodiments, if salt is present, it does not contribute more than 0.05 mS / cm or 0.1 mS / cm to the ionic conductivity. In some embodiments, the solid composition may include one or more conductivity promoters. In some embodiments, the electrolyte may include one or more filler materials, including ceramic fillers such as Al2O3. Fillers, if used, may or may not be ion conductors depending on the particular embodiment. In some embodiments, the composite may include one or more dispersing agents. Additionally, in some embodiments, the organic phase of the solid composition may include one or more additional organic components to facilitate the production of an electrolyte having desirable mechanical properties for a particular application.

[0063] In some embodiments discussed further below, the solid composition is incorporated into or prepared for incorporation into an electrode and includes an electrochemically active material and, optionally, an electronically conductive additive. Examples of electrode components and compositions that include argyrodite are provided below.

[0064] In some embodiments, the electrolyte may include an electrode stabilizer that can be used to form a passivation layer on the surface of the electrode. Examples of electrode stabilizers are described in U.S. Patent No. 9,093,722. In some embodiments, the electrolyte may include a conductivity promoter, filler, or organic component, as described above.

[0065] In some embodiments, the composite is provided as a slurry or paste. In such cases, the composition includes a solvent that is subsequently evaporated. Additionally, the composition may include one or more components for shelf stability. Such compounds may include acrylic resins. Once ready for processing, the slurry or paste may be cast or spread onto a substrate, as appropriate, and allowed to dry. In situ processing may then be performed as described above.

[0066] [In situ processing of thiophilic metal-doped argyrodite in composites] In some embodiments, a phase transition within the inorganic conductor particles after incorporation into a composite can be induced by heat treatment without degrading the components of the organic phase. FIG. 2 is a process flow diagram illustrating operations for forming a composite film. A composite film is provided that includes a thiophilic metal-doped argyrodite and / or its precursor in a polymer. Unlike methods that place an inorganic material in an organic material for sintering, the polymer in operation 202 is the polymer that will be included in the final composite material (or its precursor). Examples of polymers are described above. As noted above, the inorganic phase may include a thiophilic metal-doped argyrodite and / or its precursor. In some embodiments, the inorganic phase in 202 does not include argyrodite, but rather an argyrodite precursor (e.g., MCl). x , LiCl, Li2S, and P2S5, or Li 6-x-(z*y) M z y PS 5-x Hal 1+x MCl for creating x , LiCl, MS x In some embodiments, the inorganic phase in 202 contains only argyrodite and argyrodite precursors (e.g., Li 6-x-(z*y) M z y PS 5-x Hal 1+x, LiCl, MCl, LiS, and P2S5). In some embodiments, the inorganic phase at 202 also comprises argyrodite substantially free of unreacted precursors. At 204, the composite film is heated under pressure to form a composite film comprising argyrodite.

[0067] The pressure may be, for example, on the order of 1 MPa to 600 MPa, or 1 MPa to 100 MPa. During operation 204, one or more of the following occurs: the argyrodite reaction is carried out to completion, the argyrodite is fully or partially crystallized, and the argyrodite particles are sintered to form sintered particles. The temperature is sufficiently low to prevent thermal degradation of the polymer phase. As noted above, this differs from calcination operations, which are performed at high temperatures to calcinate the particles in the polymer while burning the polymer. Such operations may embed the polymer to form a composite.

[0068] Figure 3 is a process flow diagram illustrating certain operations in a method for making a composite electrolyte provided herein. The method of Figure 3 is an example of a method according to Figure 2. In the method of Figure 3, operation 302 involves mechanochemical synthesis of a thiophilic metal-doped argyrodite. As discussed above, this can involve high-energy ball milling of the argyrodite precursor. According to various embodiments, the reaction can be allowed to go to completion, or the ball milling can be stopped to intentionally leave some argyrodite precursor unreacted.

[0069] In some embodiments, the thiophilic metal-doped argyrodite is then externally annealed and then mixed with a polymer to form a composite film. The annealing can involve one or more of reacting unreacted precursors, initiating crystallization, and growing crystallites, which can then include fusion if the crystallites grow across the particles. In some embodiments, the argyrodite (and unreacted precursors, if any) is mixed with a polymer to form a composite film without annealing.

[0070] In 304, the composite film is heated under pressure as described above with respect to operation 204 of Figure 2. According to various embodiments, operations 204 and 304 can include sintering, which results in crystallite growth and can include the fusion of discrete particles. During sintering, the particulate green body is transformed into a polycrystalline monolithic body.

[0071] Fused particles may be characterized by having necks or narrowed regions where multiple particles have fused together. For example, ball-milled particles may be nominally round, but upon sintering, the particles fuse together to form larger, non-circular particles. The sintered particles form particle networks in the composite, with certain composites containing multiple particle networks. Fused particles may be characterized by a dimension in the plane of the film (xy plane) that is much larger than the z direction. For example, the particle aspect ratio (z:x or z:y dimension) may be less than 0.8, less than 0.5, or less than 0.1.

[0072] Sintering involves bulk diffusion from particle to particle through the necks between particles. To achieve this process, the temperature is raised to approximately one-half to three-quarters of the particle's melting temperature. For oxide conductors, the processing temperatures are in the range of over 1000°C, which can significantly limit the material's integration, phase stability, compatibility with other materials, and processing costs. The argyrodite-type ionic conductors described herein require processing temperatures of no more than 500°C to 550°C, making them much easier to process than oxides. Argyrodite formation occurs at temperatures as low as 150°C, with grain growth beginning at 300°C.

[0073] In some embodiments, liquid-phase assisted sintering is performed. Liquid-phase assisted sintering can be performed at low temperatures, for example, below 350°C or below 300°C. Argyrodite is completely soluble in ethanol and partially soluble in solvents such as tetrahydrofuran, N-methylpyrrolidone, acetonitrile, and ethyl propionate. This solubility in common solvents can be exploited for liquid-phase assisted sintering of these materials to facilitate further processing. Figure 4 is a process flow diagram illustrating operations in a method for forming a composite that includes liquid-phase assisted sintering. In operation 402, argyrodite is mixed with a polymer and sintered in a solvent.

[0074] Argyrodite can be synthesized in situ using a solvent approach before or as part of operation 402. A polymer can be added during or after synthesis, and the mixture can be cast in solution or slurry form to form a green composite film. A small amount of an argyrodite-based solvent (e.g., ethanol, tetrahydrofuran, N-methylpyrrolidone, acetonitrile, or ethyl propionate) can be added to the composite slurry. The solvent can be incorporated into the composite film in various ways, such as as the primary solvent, a cosolvent, a slurry additive, a solvent-containing inorganic powder, exposure of the composite to vapor, or immersion. During processing, the solvent improves particle lubrication and allows interparticle material transport through the liquid phase, while evaporation converts the dissolved argyrodite to a solid, improving interparticle contact, reducing porosity, and improving the material's conductivity and mechanical strength. Liquid-phase-assisted sintering can potentially help reduce processing requirements, such as pressure, temperature, and, potentially, time. Once sintered, the composite film is heated under pressure in operation 404 to improve its conductivity.

[0075] [Device] The composites described herein can be incorporated into any device that uses an ionic conductor, such as, but not limited to, batteries and fuel cells. For example, in lithium batteries, the composites can be used as an electrolyte separator. In some embodiments, they may be used in electrolyte separators with undoped argyrodite in one or more of the electrodes. In some embodiments, they may not be used in the negative electrode, for example, due to the possibility of reducing the metal dopant.

[0076] In some embodiments, the hybrid solid composition does not contain added salts. Lithium salts (e.g., LiPF6, LiTFSI), potassium salts, sodium salts, etc. may not be necessary due to contact between the ion-conducting particles. In some embodiments, the solid composition consists essentially of ion-conducting inorganic particles and an organic polymer matrix. However, in alternative embodiments, one or more additional components may be added to the hybrid solid composition.

[0077] The electrode composition further comprises an electrode active material and, optionally, a conductive additive. Examples of positive and negative electrode compositions are shown below.

[0078] Examples of the positive electrode composition are shown in the table below. [Table 1]

[0079] According to various embodiments, the positive electrode active material is a transition metal oxide, such as lithium nickel cobalt manganese oxide (LiNiCoMnO2, or NMC). 0.6 Mn 0.2 Co 0.2 O2 (NMC-622), LiNi 0.4 Mn 0.3 Co 0.3Various forms of active material such as 02 (NMC-4330) may be used. The lower end of the weight percent range is set by energy density; compositions having less than 65 weight percent active material may be ineffective due to low energy density.

[0080] Any suitable argyrodite can be used. An example of an argyrodite that maintains high ionic conductivity and inhibits hydrogen sulfide is Li 5.4 Cu 0.1 PS 4.6 Cl 1.4 Compositions having less than 10 wt. % argyrodite include Li + Low conductivity.

[0081] Electronically conductive additives are useful for active materials with poor electronic conductivity, such as NMC. Carbon black is one example of such an additive, but other carbon-based additives, including other types of carbon black, activated carbon, carbon fiber, graphite, graphene, and carbon nanotubes (CNTs), may also be used. Additions below 1 wt.% may not be sufficient to improve electronic conductivity, while additions above 5% may result in reduced energy density and impaired contact between the active material and the argyrodite.

[0082] Any suitable organic phase may be used. In certain embodiments, a hydrophobic block copolymer having both a plastic copolymer segment and an elastic copolymer segment is used. Examples include styrene-based block copolymers such as styrene-ethylene / butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), and styrene-ethylene / propylene-styrene (SEPS), as well as isoprene rubber (IR). A content of less than 1 wt. % may not be sufficient to achieve the desired mechanical properties, while a content of more than 5% may result in a decrease in energy density and / or impaired contact between the active material, argyrodite, and carbon.

[0083] Examples of the composition of the negative electrode are shown in the table below. [Table 2]

[0084] Graphite is used as a secondary active material to improve the initial coulombic efficiency (ICE) of Si anodes. Si suffers from a lower ICE (e.g., less than 80% in some cases) than NMC and other cathodes, causing irreversible capacity loss on the first cycle. Graphite has a high ICE (e.g., greater than 90%) and can be used at full capacity. Hybrid anodes that utilize Si and graphite as active materials have a higher ICE with higher graphite content, meaning that by adjusting the Si / graphite ratio, the anode ICE can be matched to the cathode ICE, preventing irreversible capacity loss on the first cycle. Because the ICE can be varied through processing, a relatively wide range of graphite content can be achieved depending on the specific anode and its processing. Furthermore, graphite can improve electronic conductivity and help densify the anode.

[0085] Any suitable argyrodite can be used. An example of an argyrodite that maintains high ionic conductivity and inhibits hydrogen sulfide is Li 5.4 Cu 0.1 PS 4.6 Cl 1.4 Compositions having less than 10 wt. % argyrodite include Li + As noted above, in some embodiments, doped argyrodite may be used in the separator but is not or is limited to be used in the negative electrode.

[0086] In some embodiments, high surface area electronically conductive additives (e.g., carbon black) may be used. Si has low electronic conductivity, and such additives can be useful in addition to graphite (which is an excellent electronic conductor but has a low surface area). However, the electronic conductivity of Si alloys is reasonably high, and in some embodiments, the use of additives may not be necessary. Also, other high surface area carbons (carbon black, activated carbon, graphene, carbon nanotubes) can be used in place of Super C.

[0087] Any suitable organic phase may be used. In certain embodiments, a hydrophobic block copolymer having both a plastic copolymer segment and an elastic copolymer segment is used. Examples include styrene-based block copolymers such as styrene-ethylene / butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), and styrene-ethylene / propylene-styrene (SEPS), as well as isoprene rubber (IR). A content of less than 1 wt. % may not be sufficient to achieve the desired mechanical properties, while a content of more than 5% may result in a decrease in energy density and / or impaired contact between the active material, argyrodite, and carbon.

[0088] Provided herein are alkali metal and alkali metal ion batteries comprising a negative electrode, a positive electrode, and a compatible solid electrolyte composition as described above in operative association with the negative electrode and the positive electrode. The batteries may also include a separator for physically separating the negative electrode and the positive electrode, which may be a solid electrolyte composition.

[0089] Suitable negative electrodes include, but are not limited to, negative electrodes formed from lithium metal, lithium alloys, sodium metal, sodium alloys, carbonaceous materials such as graphite, and combinations thereof. Suitable positive electrodes include, but are not limited to, positive electrodes formed from transition metal oxides, doped transition metal oxides, metal phosphates, metal sulfides, lithium iron phosphate, sulfur, and combinations thereof. In some embodiments, the positive electrode may be a sulfur positive electrode.

[0090] In alkali metal-air batteries, such as lithium-air batteries, sodium-air batteries, and potassium-air batteries, the positive electrode is oxygen permeable (e.g., mesoporous carbon, porous aluminum, etc.), and the positive electrode may optionally contain a metal catalyst (e.g., manganese, cobalt, ruthenium, platinum, or silver catalyst, or a combination thereof) to enhance the reduction reaction that occurs between lithium ions and oxygen at the positive electrode.

[0091] In some embodiments, a lithium-sulfur cell is provided that includes a lithium metal anode and a sulfur-containing cathode. In some embodiments, the solid composite electrolyte described herein uniquely enables both a lithium metal anode by preventing dendrite formation and a sulfur cathode by not dissolving polysulfide intermediates that form at the cathode during discharge.

[0092] A separator formed of any suitable material permeable to ion flow can also be included to prevent the negative and positive electrodes from coming into direct electrical contact with each other. Note that the electrolyte compositions described herein are solid compositions and can therefore function as separators, especially when they are in film form.

[0093] In some embodiments, the solid electrolyte composition functions as the electrolyte between the negative and positive electrodes of an alkali ion battery, which relies on the intercalation of alkali ions during cycling.

[0094] As noted above, in some embodiments, the solid composite composition may be incorporated into an electrode of a battery. The electrolyte may be a compatible solid electrolyte, as described above, or any other suitable electrolyte, including a liquid electrolyte.

[0095] In some embodiments, the battery comprises electrode / electrolyte bilayers, each layer incorporating an ionically conductive solid composite material described herein.

[0096] 5A shows an example of a schematic diagram of a cell according to certain embodiments of the present invention. The cell includes an anode current collector 502, an anode 504, an electrolyte / separator 506, a cathode 508, and a cathode current collector 510. The anode current collector 502 and the cathode current collector 510 may be any suitable electronically conductive material, such as copper, steel, gold, platinum, aluminum, or nickel. In some embodiments, the anode current collector 502 is copper, and the cathode current collector 510 is aluminum. The current collectors may be in any suitable form, such as a sheet, foil, mesh, or foam. According to various embodiments, one or more of the anode 504, the cathode 508, and the electrolyte / separator 506 are solid composites comprising argyrodite doped with a thiophilic metal, as described above. In some embodiments, two or more of the negative electrode 504, the positive electrode 508, and the electrolyte 506 are solid composites comprising thiophilic metal-doped argyrodites as described above.

[0097] In some embodiments, the current collector is a porous material that can be embedded in a corresponding electrode. For example, it can be a mesh. Electrodes containing hydrophobic polymers such as those described above may not adhere well to foil current collectors, whereas meshes provide good mechanical contact. In some embodiments, two composite membranes described herein can be pressed against a mesh current collector to form a current collector embedded within the electrode.

[0098] FIG. 5B shows an example schematic of a lithium metal cell assembled according to certain embodiments of the present invention. The assembled cell includes an anode current collector 502, an electrolyte / separator 506, a cathode 508, and a cathode current collector 510. During the first charge, lithium metal is generated and plated onto the anode current collector 502, forming the anode. One or both of the electrolyte 506 and the cathode 508 may be a composite material as described above. In some embodiments, the cathode 508 and the electrolyte 506 together form an electrode / electrolyte bilayer. FIG. 5C shows an example schematic of a cell according to certain embodiments of the present invention. The cell includes an anode current collector 502, an anode 504, a cathode / electrolyte bilayer 512, and a cathode current collector 510. Each layer in the bilayer may include argyrodite. Such a bilayer may be prepared, for example, by preparing an electrolyte slurry and depositing it on the electrode layers.

[0099] All components of the battery can be contained in or packaged within a suitable rigid or flexible container with external leads or contacts for establishing electrical connection to the negative and positive electrodes in accordance with known techniques.

[0100] [Example] Appropriate amounts of P2S5, Li2S, LiCl, and CuS were ball-milled to prepare Li 5.4 Cu 0.1 PS 4.6 Cl 1.4 A portion of the ball-milled material was annealed at 450°C, and the conductivity and hydrogen sulfide release rate were compared to the copper-free base material.

[0101] Annealed Li 5.4 Cu 0.1 PS 4.6 Cl 1.4 The same annealed base material Li 5.6 PS 4.6 Cl 1.4The conductivity was 6.24 mS / cm compared to 7.86 mS / cm, indicating that 79% of the conductivity was retained. The amount of hydrogen sulfide released from the copper-doped material was only 59% of that of the parent material, demonstrating a clear advantage.

[0102] Figure 6 shows the Li 5.4 Cu 0.1 PS 4.6 Cl 1.4 Powder diffraction pattern of Li6PS5Cl with overlaid reference lines from argyrodite-type Li6PS5Cl. The strong agreement between the measured pattern and the reference lines suggests that this new Cu-containing material has an argyrodite structure. The absence of peaks not corresponding to the reference lines suggests the absence of significant crystalline contamination.

[0103] Appropriate amounts of P2S5, Li2S, LiCl, and CuS were ball-milled to prepare Li 5.8 Cu 0.1 PS5Cl was produced. A portion of this ball-milled material was annealed at 450 °C. Figure 7 shows the Li 5.8 Cu 0.1 Powder diffraction pattern of PS5Cl with overlaid reference lines from argyrodite-type Li6PS5Cl. The strong agreement between the measured pattern and the reference lines suggests that this new Cu-containing material has an argyrodite structure. The lack of peaks not corresponding to the reference lines also suggests the absence of significant crystalline contamination.

[0104] Figure 8 shows the cumulative hydrogen sulfide gas release, normalized in mg of H2S per gram of argyrodite (mgH2S / g argyrodite), for various metal-doped and parent materials. The conductivities of these materials are listed in the legend. The results in Figure 8 indicate that 1) metal doping reduces H2S at different Cl concentrations, 2) different dopant metals perform (to slightly different degrees), and 3) higher doping levels suppress hydrogen sulfide release more, while slightly decreasing conductivity.

[0105] [Sulfide-based ionic conductors doped with additional thiophilic metals] The introduction of thiophilic metals could also be beneficial for other sulfide-based ionic conductors, although the usefulness of this approach depends heavily on the structure of the particular material. For example, glassy Li3PS4 alone, or doped with other salts such as LiI, has been used as a lithium-ion conductor in lithium-ion batteries. While it is conceivable that thiophilic metals could be incorporated into these glasses, these materials by themselves have very low hydrogen sulfide release, and therefore it is not reasonable to degrade the lithium-ion conductivity of an already relatively poorly conducting material. On the other hand, Li7P3S 11 The addition of a thiophilic metal to Li3PS4 may offer some benefits by making this material more reactive in hydrogen sulfide release compared to Li3PS4. The most reactive sulfur site in this material may be the bridging sulfur in the Li3PS3-S-PS3Li3 portion of the structure. While this sulfur has two covalent bonds with the phosphorus atom and no ionic bond with the lithium atom, the crystal structure of this material indicates the possibility of a weak interaction with the lithium atom in the structure. Thus, in some embodiments, this lithium atom may be substituted with a thiophilic metal to suppress the hydrogen sulfide release associated with this sulfur center. This effect is due to the presence of one or more S, which are otherwise the most reactive type of site in sulfide-type lithium ion conductors. 2- The binding of all thiophilic metal centers to the Li site is expected to be weaker than in the case of argyrodite. 10 GeP2S 12 Other lithium ion conducting sulfides, such as Li3PS4, may also benefit in some way from doping with thiophilic metals as described herein, but as with Li3PS4, all of the sulfur atoms in this system and its derivatives are in a less reactive bonding environment, so baseline hydrogen sulfide release is not expected to be as severe.

[0106] [Item 1] 1. A composition comprising a thiophilic metal-doped alkali metal argyrodite sulfide-based ionic conductor, The composition, wherein the thiophilic metal is selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), molybdenum (Mo), and combinations thereof. [Item 2] Item 2. The composition of claim 1, wherein the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:120. [Item 3] Item 2. The composition of claim 1, wherein the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is at least 1:50. [Item 4] 4. The composition of any one of items 1 to 3, wherein the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is 1:4 or less. [Item 5] 4. The composition of any one of items 1 to 3, wherein the ratio of thiophilic metal atoms to sulfur atoms in the alkali metal argyrodite sulfide-based ionic conductor is 1:20 or less. [Item 6] 6. The composition of any one of items 1 to 5, wherein the alkali metal in the alkali metal argyrodite sulfide-based ionic conductor is lithium (Li), sodium (Na), or potassium (K). [Item 7] 6. The composition of any one of items 1 to 5, wherein the alkali metal in the alkali metal argyrodite sulfide-based ionic conductor is lithium. [Item 8] The alkali metal argyrodite sulfide-based ionic conductor is a composition represented by the following formula: A 7-x-(z*y) M z y PS 6-x Hal x where: A is an alkali metal; M is a thiophilic metal; Hal is selected from chlorine (Cl), bromine (Br), and iodine (I), z is the oxidation state of the metal, 0 < x ≦ 2, and 0 < y < (7 - x) / z, the composition according to item 1. [Item 9] z > +1, the composition according to item 8. [Item 10] z = +2, the composition according to item 8. [Item 11] 1 ≦ x ≦ 1.6, the composition according to any one of items 8 to 10. [Item 12] 0.1 ≦ y ≦ 2 - x, the composition according to any one of items 8 to 11. [Item 13] The ratio of the thiophilic metal atom to the sulfur atom in the alkali metal aludidite sulfide-based ion conductor is at least 1:¬120, the composition according to any one of items 8 to 12. [Item 14] The ratio of the thiophilic metal atom to the sulfur atom in the alkali metal aludidite sulfide-based ion conductor is at least 1:¬50, the composition according to any one of items 8 to 12. [Item 15] The alkali metal aludidite sulfide-based ion conductor is a composition represented by the following formula, A 7-x+n-(z*y) M z y PS 6-x Hal x+n Here, A is an alkali metal, M is a thiophilic metal, Hal is selected from chlorine (Cl), bromine (Br), and iodine (I), z is the oxidation state of the metal, 0.05 ≦ n ≦ 0.9, -3.0x + 1.8 ≦ n ≦ -3.0x + 5.7, 0 ≦ y < (7 - x) / z, and The composition according to item 1, where 0 < x ≤ 2. [Item 16] The composition according to item 15, where z > +1. [Item 17] The composition according to item 15, where z = +2. [Item 18] The composition according to any one of items 15 to 17, where the ratio of the thiophilic metal atom to the sulfur atom in the alkali metal aludidite sulfide-based ion conductor is at least 1:120. [Item 19] The composition according to any one of items 15 to 17, where the ratio of the thiophilic metal atom to the sulfur atom in the alkali metal aludidite sulfide-based ion conductor is at least 1:50. [Item 20] The composition according to any one of items 1 to 19, where the alkali metal aludidite sulfide-based ion conductor is a single-phase material. [Item 21] A composition comprising a composite membrane of particles containing the alkali metal aludidite sulfide-based ion conductor according to any one of items 1 to 20 within a polymer. [Item 22] The composition according to item 21, where the polymer is a hydrophobic polymer. [Item 23] The composition according to item 21, where the polymer is not ion-conductive. [Item 24] The composition according to item 21, where the polymer is styrene ethylene butylene styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene / butadiene-styrene (SIBS), styrene-ethylene / propylene (SEP), styrene-ethylene / propylene-styrene (SEPS), or isoprene rubber (IR). [Item 25] The composition according to any one of items 21 to 24, where the composite membrane consists of 0.5 wt% to 60 wt% of the polymer. [Item 26] 25. The composition according to any one of items 21 to 24, wherein the composite membrane consists of 5% to 30% by weight of polymer. [Item 27] 20. A composition comprising an electrochemically active material, the alkali metal argyrodite sulfide-based ionic conductor according to any one of items 1 to 19, carbon conductive particles, and an organic polymer. [Item 28] 28. The composition of claim 27, wherein the electrochemically active material comprises a transition metal oxide. [Item 29] Item 29. The composition according to item 28, wherein the electrochemically active material is 65% to 88% by weight of the composition. [Item 30] 30. The composition according to item 28 or 29, wherein the alkali metal argyrodite sulfide-based ionic conductor is 10% to 33% by weight of the composition. [Item 31] 28. The composition of claim 27, wherein the electrochemically active material comprises one or more of a graphite-based material and a silicon-containing material. [Item 32] Item 32. The composition according to item 31, wherein the silicon content of the composition is 15% to 50% by weight. [Item 33] Item 33. The composition according to item 31 or 32, wherein the graphite-based material is contained in an amount of 5% to 40% by weight of the composition. [Item 34] Item 28. The composition according to item 27, wherein the alkali metal argyrodite sulfide-based ionic conductor is contained in an amount of 10% by weight to 50% by weight of the composition.

Claims

[Claim 1] 1. A composition comprising a thiophilic metal-doped alkali metal argyrodite sulfide-based ionic conductor, the thiophilic metal is selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), mercury (Hg), molybdenum (Mo), and combinations thereof.

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