Inorganic compounds having an argyrodite-type structure, process for their preparation and their use in electrochemical applications - Patents.com

Abstract

The present technology relates to inorganic compounds having an argyrodite-type structure based on alkali metals, which are obtained by a preparation method comprising a step of grinding an alkali metal sulfide, an alkali metal sulfate, phosphorus pentasulfide, and an alkali metal halide. Also described are electrode materials, electrodes, electrolytes, and their use in electrochemical cells, such as electrochemical accumulators, in particular all-solid-state batteries, which comprise said inorganic compounds having an argyrodite-type structure.

Description

[Technical field]

[0001] Related Applications This application claims priority under applicable law to Canadian Patent Application No. 3,136,69, filed October 27, 2021, and to Canadian Patent Application No. 3,136,69, filed October 12, 2022, entitled "COMPOSES INORGANIQUES POSSEDANT UNE STRUCTURE DE TYPE ARGYRODITE, LEURS PROCEDES DE PREPARATION ET LEURS UTILISATIONS DANS DES APPLICATIONS ELECTROCHIMIQUES," the contents of which are incorporated herein by reference in their entirety and for all purposes.

[0002] Technical Field This application relates to the field of oxysulfide-based inorganic compounds having an argyrodite-type structure and their use in electrochemical applications. More particularly, this application relates to the field of oxysulfide-based inorganic compounds having an argyrodite-type structure, electrode materials and solid electrolytes containing them, their preparation methods, and their use in electrochemical cells, in particular all-solid-state batteries. [Background technology]

[0003] background Inorganic compounds such as sulfide-based ceramics, glasses and glass-ceramics are promising materials for many technological applications as they enable the development of substantially safer all-solid-state electrochemical systems.

[0004] Moreover, sulfide-based inorganic compounds exhibit a wide electrochemical stability window and substantially higher ionic conductivities at room temperature. Indeed, inorganic solid electrolytes containing them exhibit ionic conductivities at room temperature comparable to those of liquid organic electrolytes and thus substantially higher than those of their counterparts based on the use of solid polymer electrolytes. For example, argyrodite of formula Li6PS5X (where X is Cl, Br or I) exhibits ionic conductivities of 1000 mS.cm at room temperature. -1 The ionic conductivity ranges.

[0005] However, the use of inorganic compounds of the argyrodite type is limited by the high cost of their production, in particular due to the use of lithium sulfide (Li2S) and a sulfur source as precursors, as well as the high-temperature annealing step that allows to obtain interesting ionic conductivities. Therefore, one of the key elements of the industrial requirements related to the production of inorganic compounds of this type is to minimize the costs by reducing the Li2S utilization and the annealing temperature while maintaining a fairly high ionic conductivity.

[0006] Furthermore, inorganic compounds of the argyrodite type are accompanied by problems related to their interfacial stability as well as their stability in ambient air and humidity. More precisely, these inorganic solid electrolytes, when in contact with moist air, generate hydrogen sulfide (H2S) gas and therefore must be prepared, assembled and operated under an inert atmosphere. One strategy used to solve this problem involves the use of inorganic argyrodite compounds based on oxysulfides. Indeed, the partial substitution of sulfur and / or lithium atoms in these inorganic compounds by oxygen significantly reduces the H2S generation in the presence of moisture.

[0007] Thus, there remains a need for the development of inorganic compounds for use in all-solid-state electrochemical systems that eliminate one or more of the above-mentioned drawbacks. Summary of the Invention [Means for solving the problem]

[0008] Abstract According to some embodiments, embodiments of the technology described herein include the following items: 1. A method for preparing an inorganic compound having an alkali metal-based aludidite-type structure, the method including the step of grinding an alkali metal sulfide, an alkali metal sulfate, phosphorus pentasulfide, and an alkali metal halide, wherein the alkali metal is selected from lithium, sodium, and potassium, for example, the alkali metal is lithium. 2. The method of item 1, wherein the alkali metal halide is selected from an alkali metal fluoride, an alkali metal chloride, an alkali metal bromide, an alkali metal iodide, and a mixture of at least two of them. 3. The method of item 2, wherein the alkali metal halide is an alkali metal chloride. 4. The method of item 2, wherein the alkali metal halide is an alkali metal bromide. 5. The method of item 2, wherein the alkali metal halide is an alkali metal iodide. 6. The method of item 2, wherein the alkali metal halide is a mixture of an alkali metal chloride and an alkali metal bromide. 7. The method of item 2, wherein the alkali metal halide is a mixture of an alkali metal chloride, an alkali metal bromide, and an alkali metal iodide. 8. The aludidite-type structure is of the formula M 6-x PS 5-x-y O y Z 1+x wherein M is an alkali metal selected from Li, Na, and K, for example, M is Li, Z is a halogen atom selected from F, Cl, Br, and I, x represents a number of Z greater than 1 or equal to zero, y is a number different from zero (for example, 0 ≦ x ≦ 1 and 0 < y ≦ 1), the method of any one of items 1 to 7. 9. The method of item 8, wherein x is a number different from zero (for example, 0 < x ≦ 1). 10. The method of item 8 or 9, wherein x and y are selected to achieve electroneutrality. 11. The argyrodite structure has the formula M 5.4 P.S. 4.3 O 0.1 Cl 1.6 , M 5.4 P.S. 4.1 O 0.3 Cl 1.6 , M 5.4 P.S. 3.9 O 0.5 Cl 1.6 , M 5.4 P.S. 3.65 O 0.75 Cl 1.6 , M 5.7 P.S. 4.4 O 0.3 Cl 1.3 , M 5.4 P.S. 4.1 O 0.3 Cl 1.6 , M 5.4 P.S. 3.9 O 0.5 Cl 1.6 , M 5.4 P.S. 4.1 O 0.3 Br 1.6 , M 5.4 P.S. 4.1 O 0.3 ClBr 0.6 , M 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 , M 5.4 P.S. 4.1 O 0.3 Cl 0.6 Br, M 5.4 P.S. 4.1 O 0.3 ClBr 0.5 I 0.1 , M 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I 0.1 , M 5.4 P.S. 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 and M.5.4 P.S. 4.1 O 0.3 ClBr 0.4 I 0.2 (M is as defined in item 8) 12. The argyrodite-type structure has the formula Li 5.4 P.S. 4.3 O 0.1 Cl 1.6 , Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 , Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 , Li 5.4 P.S. 3.65 O 0.75 Cl 1.6 , Li 5.7 P.S. 4.4 O 0.3 Cl 1.3 , Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 , Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 , Li 5.4 P.S. 4.1 O 0.3 Br 1.6 , Li 5.4 P.S. 4.1 O 0.3 ClBr 0.6 , Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 , Li 5.4 P.S. 4.1 O 0.3 Cl 0.6 Br, Li 5.4 P.S. 4.1 O 0.3 ClBr 0.5 I 0.1 , Li 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I0.1 、 Li 5.4 PS 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 and Li 5.4 PS 4.1 O 0.3 ClBr 0.4 I 0.2 A method according to any one of items 8 to 10, selected from inorganic compounds having an aludite-type structure. 13. The aludite-type structure has the formula M 6-x-2y PS 5-x-y O y Z 1+x where M is an alkali metal selected from Li, Na and K, for example, M is Li, Z is a halogen atom selected from F, Cl, Br and I, x represents the number of Z greater than 1 or is equal to zero, and y is a number different from zero (for example, 0 ≦ x ≦ 1 and 0 < y ≦ 1), a method according to any one of items 1 to 7. 14. The method according to item 13, wherein x is a number different from zero (for example, 0 < x ≦ 1). 15. The aludite-type structure has the formulas M 5.2 PS 4.3 O 0.1 Cl 1.6 , M 5.1 PS 4.4 O 0.3 Cl 1.3 and M 4.8 PS 4.1 O 0.3 Cl 1.6 (where M is as defined in item 13), a method according to item 13 or 14, selected from inorganic compounds having an aludite-type structure. 16. The aludite-type structure has the formulas Li 5.2 PS 4.3 O 0.1 Cl 1.6 , Li 5.1 PS 4.4 O 0.3 Cl 1.3 and Li 4.8 PS 4.1 O 0.3 Cl 1.6Item 16. The method of item 15, wherein the compound is selected from inorganic compounds having an argyrodite type structure represented by the formula: 17. The method of any one of items 1 to 16, wherein the grinding step is carried out using a mill. 18. The method of item 17, wherein the mill is a planetary mill. 19. The method of any one of items 1 to 18, wherein the grinding step is carried out at a rotation speed in the range of about 300 rpm to about 800 rpm. 20. The method of any one of items 1 to 18, wherein the grinding step is carried out at a rotation speed in the range of about 400 rpm to about 700 rpm. 21. The method of any one of items 1 to 18, wherein the grinding step is carried out at a rotation speed in the range of about 500 rpm to about 700 rpm. 22. The method of any one of items 1 to 18, wherein the grinding step is carried out at a rotational speed of about 600 rpm. 23. The method of any one of items 1 to 22, wherein the milling step is carried out for a time period ranging from about 5 hours to about 20 hours. 24. The method of any one of items 1 to 22, wherein the milling step is carried out for about 10 hours. 25. The method of any one of items 1 to 24, wherein the milling step is carried out at a ratio of milling beads:precursor ranging from about 10 to about 30. 26. The method of any one of items 1 to 24, wherein the milling step is carried out at a ratio of milling beads:precursor of about 30. 27. The method of any one of items 1 to 26, further comprising an annealing step carried out at a maximum temperature of about 400°C. 28. The method of any one of items 1 to 26, further comprising an annealing step carried out at a maximum temperature of about 300°C. 29. The method of any one of items 1 to 26, which does not include an annealing step. 30. An inorganic compound having an argyrodite-type structure, obtainable by the process defined in any one of items 1 to 29. 31. An electrode material comprising an electrochemically active material and an inorganic compound having an argyrodite-type structure as defined in item 30 or obtained by the process as defined in any one of items 1 to 29. 32. The electrode material of item 31, in which an inorganic compound having an argyrodite-type structure is present as an additive. 33. The electrode material of item 31 or 32, in which an inorganic compound having an argyrodite-type structure is present as a coating material. 34. The electrode material of item 33, wherein the coating material forms a coating layer on a surface of the electrochemically active material. 35. The electrode material of any one of items 31 to 34, wherein the electrochemically active material is selected from a metal oxide, a metal sulfide, a metal oxysulfide, a metal phosphate, a metal fluorophosphate, a metal oxyfluorophosphate, a metal sulfate, a metal halide, a metal fluoride, sulfur, selenium, and a combination of at least two thereof. 36. The electrode material of item 35, wherein the metal of the electrochemically active material is selected from titanium (Ti), iron (Fe), manganese (Mn), vanadium (V), nickel (Ni), cobalt (Co), aluminum (Al), chromium (Cr), copper (Cu), zirconium (Zr), niobium (Nb), molybdenum (Mo), tungsten (W), and combinations of at least two of them. 37. The electrode material of item 35 or 36, wherein the metal of the electrochemically active material further comprises an alkali metal or alkaline earth metal selected from lithium (Li), sodium (Na), potassium (K) and magnesium (Mg). 38. The electrode material of any one of items 31 to 37, wherein the electrochemically active material is a lithium metal oxide. 39. The electrode material of item 38, wherein the lithium metal oxide is a mixed oxide of lithium, nickel, manganese and cobalt (NCM). 40. The electrochemically active material is selected from the group consisting of non-alkali or non-alkaline earth metals, intermetallic compounds, metal oxides, metal nitrides, metal phosphides, metal phosphates, metal halides, metal fluorides, metal sulfides, metal oxysulfides, carbon, silicon (Si), silicon-carbon composites (Si-C), silicon oxide (SiO x ), silicon oxide-carbon composite (SiO x -C), tin (Sn), tin-carbon composite (Sn-C), tin oxide (SnO x ), tin oxide-carbon composite (SnO x -C) and a combination of at least two thereof. 41. The electrode material of any one of items 31 to 40, wherein the electrochemically active material further comprises a doping element. 42. The electrode material of any one of items 31 to 41, wherein the electrochemically active material further comprises a coating material. 43. The electrode material of item 42, wherein the coating material is an electronically conductive material. 44. The electrode material of item 43, wherein the electronically conductive material is carbon. 45. The electrode material of item 42, wherein the coating material is selected from Li2SiO3, LiTaO3, LiAlO2, Li2O-ZrO2, LiNbO3, other similar coating materials, and combinations of at least two of them. 46. ​​The electrode material of item 45, wherein the coating material is LiNbO3. 47. The electrode material of any one of items 31 to 46, further comprising at least one electronically conductive material. 48. The electrode material of item 47, wherein the electronically conductive material is selected from the group consisting of carbon black, acetylene black, graphite, graphene, carbon fibers, carbon nanofibers, carbon nanotubes, and mixtures of at least two of them. 49. The electrode material of item 48, wherein the electronically conductive material is a mixture of carbon black and vapor grown carbon fiber (VGCF). 50. The electrode material of any one of items 31 to 49, further comprising at least one additive. 51. The electrode material of item 50, wherein the additive is selected from inorganic ion-conducting materials, inorganic materials, glasses, glass-ceramics, ceramics, nanoceramics, salts, and combinations of at least two of them. 52. The electrode material of any one of items 31 to 51, further comprising a binder. 53. The electrode material of item 52, wherein the binder is selected from the group consisting of polymeric binders of the polyether, polycarbonate or polyester type, fluorinated polymers and water-soluble binders. 54. An electrode comprising an electrode material as defined in any one of items 31 to 53 on a current collector. 55. A self-supporting electrode comprising an electrode material as defined in any one of items 31 to 53. 56. An electrolyte comprising an inorganic compound having an argyrodite-type structure as defined in item 30 or obtained by the process defined in any one of items 1 to 29. 57. The electrolyte of item 56, wherein the electrolyte is a liquid electrolyte comprising a salt in a solvent. 58. The electrolyte of item 56, wherein the electrolyte is a gel electrolyte comprising a salt in a solvent and optionally in a solvating polymer. 59. The electrolyte of item 56, wherein the electrolyte is a solid polymer electrolyte comprising a salt in a solvated polymer. 60. An electrolyte according to any one of items 56 to 59, in which an inorganic compound having an argyrodite-type structure is present as an additive. 61. The electrolyte of item 56, wherein the electrolyte is an inorganic solid electrolyte. 62. The electrolyte of item 56, wherein the electrolyte is a polymer-ceramic hybrid solid electrolyte. 63. An electrolyte according to item 61 or 62, in which an inorganic compound having an argyrodite-type structure is present as the inorganic solid electrolyte material. 64. The electrolyte of any one of items 56 to 63, further comprising at least one additional component. 65. The electrolyte of item 64, wherein the additional component is selected from an ionically conductive material, an inorganic particle, a glass or ceramic particle, and a combination of at least two of them. 66. An electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein at least one of the positive electrode or the negative electrode is as defined in item 54 or 55 or comprises an electrode material defined in any one of items 31 to 53. 67. An electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, the electrolyte being as defined in any one of items 56 to 65. 68. The electrochemical cell of item 66 or 67, wherein the negative electrode comprises an electrochemically active material comprising an alkali metal, an alkaline earth metal, an alloy containing at least one alkali metal or alkaline earth metal, a non-alkali metal and a non-alkaline earth metal, or an alloy or intermetallic compound. 69. The electrochemical cell of item 68, wherein the electrochemically active material of the negative electrode comprises metallic lithium or an alloy containing or based on metallic lithium. 70. The electrochemical cell of any one of items 66 to 68, wherein the positive electrode is prelithiated and the negative electrode is substantially free of lithium. 71. The electrochemical cell of item 70, wherein the negative electrode is lithiated in situ during cycling of the electrochemical cell. 72. An electrochemical storage battery comprising at least one electrochemical cell as defined in any one of items 66 to 71. 73. The electrochemical storage battery of item 72, wherein the electrochemical storage battery is a battery selected from lithium batteries, lithium ion batteries, sodium batteries, sodium ion batteries, magnesium batteries and magnesium ion batteries. 74. The electrochemical storage battery of item 73, wherein the battery is a lithium battery or a lithium-ion battery. 75. The electrochemical accumulator of any one of items 72 to 74, wherein the electrochemical accumulator is an all-solid-state battery. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows the X-ray diffraction patterns obtained for the powders of Argyrodites 1-4 and 8, as described in Example 2.

[0010] [Diagram 2] FIG. 2 shows the X-ray diffraction patterns obtained for the powders of argyrodites 2 and 5 to 7, as described in Example 2.

[0011] [Diagram 3] FIG. 3 represents the X-ray diffraction patterns obtained for powders of argyrodites 2, 3, 9 and 10, as described in Example 2.

[0012] [Figure 4] FIG. 4 shows the X-ray diffraction patterns obtained for the powders of argyrodites 2 and 12-15, as described in Example 2.

[0013] [Diagram 5] FIG. 5 shows the X-ray diffraction patterns obtained for the powders of argyrodites 16 to 19, as described in Example 2.

[0014] [Figure 6] FIG. 6 represents the X-ray diffraction patterns obtained for powders of argyrodites 2, 13, 20 and 21, as described in Example 2.

[0015] [Figure 7] FIG. 7 presents lithium nuclear magnetic resonance (6Li NMR) spectra obtained for argyrodites 2 and 9, as described in Example 3.

[0016] [Figure 8] FIG. 8 depicts phosphorus nuclear magnetic resonance (31P NMR) spectra obtained for argyrodites 2 and 9, as described in Example 3.

[0017] [Figure 9] FIG. 9 depicts the lithium nuclear magnetic resonance (6Li NMR) spectrum obtained for argyrodite 7, as described in Example 3.

[0018] [Figure 10] FIG. 10 depicts a phosphorus nuclear magnetic resonance (31P NMR) spectrum obtained for argyrodite 7, as described in Example 3.

[0019] [Figure 11] FIG. 11 shows the lithium nuclear magnetic resonance (6Li NMR) spectra obtained for argyrodites 13 and 16, as described in Example 3.

[0020] [Figure 12] FIG. 12 shows phosphorus nuclear magnetic resonance ( 31 P NMR) spectra obtained for argyrodites 13 and 16, as described in Example 3.

[0021] [Figure 13] FIG. 13 shows a plot of the volume of gaseous H2S normalized by the mass of argyrodite evolved as a function of time for argyrodites 2, 7, 8, 11, 13 and 16, as described in Example 4.

[0022] [Figure 14] FIG. 14 is a graph showing ionic conductivity results as a function of temperature for cells 1 (circles), 2 (triangles), 3 (diamonds), 4 (stars) and 8 (squares), as described in Example 5(b).

[0023] [Figure 15] FIG. 15 is a graph showing ionic conductivity results as a function of temperature for cells 2 (triangles), 5 (squares), 6 (circles) and 7 (diamonds), as described in Example 5(b).

[0024] [Figure 16]FIG. 16 is a graph showing ionic conductivity results as a function of temperature for cells 2 (squares), 3 (circles), 9 (triangles) and 10 (diamonds), as described in Example 5(b).

[0025] [Figure 17] FIG. 17 is a graph showing ionic conductivity results as a function of temperature for cells 2 (squares), 12 (circles), 13 (triangles), 14 (diamonds) and 15 (stars), as described in Example 5(b).

[0026] [Figure 18] FIG. 18 is a graph showing ionic conductivity results as a function of temperature for cells 16 (squares), 17 (circles), 18 (triangles) and 19 (diamonds), as described in Example 5(b).

[0027] [Figure 19] FIG. 19 is a graph showing ionic conductivity results as a function of temperature for cells 2 (squares), 20 (circles), 13 (triangles) and 21 (diamonds), as described in Example 5(b).

[0028] [Figure 20] FIG. 20 shows cyclic voltammograms obtained for cells 22 and 23, recorded at a scan rate of 0.05 mV / s between 2.5 V and 4.2 V vs. Li / Li+ at a temperature of about 30° C., as described in Example 6(b).

[0029] [Figure 21] FIG. 21 shows graphs of charge capacity (circles) and discharge capacity (squares) and coulombic efficiency (triangles) as a function of cycle number over 100 cycles obtained for cell 24, as described in Example 7(c).

[0030] [Figure 22]FIG. 22 depicts the discharge profiles obtained for cell 24 as a function of the capacity obtained at charge and discharge currents of C / 10, C / 4 and C / 2 recorded versus Li / Li+ at a temperature of 30° C., as described in Example 7(c).

[0031] [Diagram 23] FIG. 23 depicts the discharge profiles obtained for cell 24 as a function of time obtained at charge and discharge currents of C / 10, C / 4 and C / 2 recorded versus Li / Li+ at a temperature of 30° C., as described in Example 7(c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Detailed Description The following detailed description and examples are for illustrative purposes only and should not be construed as further limiting the scope of the present invention.On the contrary, the following detailed description and examples are intended to cover all of the alternatives, modifications and equivalents that may be included as defined by this description.Objects, advantages and other features of the present inorganic compounds having an argyrodite-type structure, their preparation methods, and electrode materials, electrodes, electrolytes, electrochemical cells and electrochemical accumulators containing them will become more apparent and be better understood from the following non-limiting description and with reference to the accompanying drawings.

[0033] All technical and scientific terms and expressions used herein have the same definitions as those commonly understood by those skilled in the art related to this technology. Nevertheless, the definitions of some terms and expressions used herein are provided below.

[0034] When the term "about" is used herein, it means approximately, roughly, or approximately. For example, when the term "about" is used in relation to a numerical value, this term modifies the value by a variation of 10% above or below its nominal value. This term can also take into account, for example, experimental error or rounding of a measuring device.

[0035] When a range of values ​​is specified in this application, the lower and upper limits of the interval are always included in the definition, unless otherwise indicated. When a range of values ​​is specified in this application, all intermediate ranges and subranges, as well as individual values, contained within this range of values ​​are included in the definition.

[0036] When the article "a" is used to introduce an element in this application, the article does not have the meaning of "only one," but rather the meaning of "one or more." Of course, if the description specifies that a particular step, component, element, or feature "can" be included or "may" be included, that particular step, component, element, or feature need not be included in every embodiment.

[0037] The term "self-supporting electrode" as used herein refers to an electrode without a metal current collector.

[0038] The present technology relates to a method for preparing an inorganic compound having an argyrodite-type structure based on M2S-P2S5-M2SO4-MZ (where M is an alkali metal selected from lithium (Li), sodium (Na), potassium (K), and combinations of at least two of them, and Z is a halogen atom selected from fluorine (F), chlorine (Cl), bromine (Br), iodine (I), or combinations of at least two of them), the method including a step of directly grinding a precursor. According to some examples, M is lithium. The precursor consists of an alkali metal sulfide (M2S), an alkali metal sulfate (M2SO4), phosphorus pentasulfide (P2S5), an alkali metal halide selected from alkali metal fluoride, alkali metal chloride, alkali metal bromide, alkali metal iodide, and mixtures of at least two of them.

[0039] According to one example, the inorganic compound having an argyrodite-type respectively has the formula M 6-x PS 5-x-y O y Z 1+x and M 6-x-2y PS 5-x-y O y Z 1+x and can be, where Z and M are as defined herein, x represents a number of Z greater than 1 or is equal to zero, y is a non-zero number, for example, 0≦x≦1 and 0<y≦1. According to one example, x is a non-zero number (for example, 0<x≦1). Thus, the inorganic compound having an argyrodite-type structure respectively has the following reaction formulas: (2.5 - y / 4 - x)M2S + y / 4 M2SO4 + 1 / 2 P2S5 + (1 + x)MZ → M 6-x PS 5-x-y O y Z 1+x + y S Formula (1) (2.5 - 5 / 4y - x)M2S + y / 4 M2SO4 + 1 / 2 P2S5 + (1 + x)MZ → M 6-x-2y PS 5-x-y O y Z 1+x Formula (2) (wherein x, y, M and Z are as defined herein). It can be obtained by grinding from a precursor as defined herein according to

[0040] According to one example, when the inorganic compound has an argyrodite-type structure, x represents a number Z greater than 1 or equal to zero, and y is a number different from zero, where x and y are selected to achieve a desired stoichiometry or to achieve electroneutrality. A non-limiting example of an inorganic compound having an argyrodite-type structure according to formula 1 is represented by the formula M 5.4 P.S. 4.3 O 0.1 Z 1.6 , M 5.4 P.S. 4.1 O 0.3 Z 1.6 , M 5.4 P.S. 3.9 O 0.5 Z 1.6 , M 5.4 P.S. 3.65 O 0.75 Z 1.6 and M. 5.7 P.S. 4.4 O 0.3 Z 1.3 where M and Z are as defined herein. When the inorganic compound has an argyrodite-type structure that contains only a small amount of alkali metal (i.e., an inorganic compound having an argyrodite-type structure according to formula 2), x represents the number of Z greater than 1 or equal to zero, and y is a number different from zero, with x and y selected to obtain the desired stoichiometry. Non-limiting examples of inorganic compounds having an argyrodite-type structure according to formula 2 include inorganic compounds having the formula M 5.1 P.S. 4.4 O 0.3 Z 1.3 and M. 4.8 P.S. 4.1 O 0.3 Z 1.6 where M and Z are as defined herein.

[0041] In the present example, Z is a chlorine atom and the alkali metal halide is an alkali metal chloride. For example, an inorganic compound having an argyrodite structure is represented by the formula M 5.4 P.S. 4.3 O 0.1 Cl 1.6 , M 5.4 P.S. 4.1 O 0.3 Cl 1.6 , M 5.4 P.S. 3.9 O 0.5 Cl 1.6 , M 5.4 P.S. 3.65 O 0.75 Cl 1.6 , M 5.7 P.S. 4.4 O 0.3 Cl 1.3 , M 5.1 P.S. 4.4 O 0.3 Cl 1.3 and M. 4.8 P.S. 4.1 O 0.3 Cl 1.6 where M is as defined herein.

[0042] According to another embodiment of interest, Z is a bromine atom and the alkali metal halide is an alkali metal bromide. For example, an inorganic compound having an argyrodite-type structure can be represented by the formula M 5.4 P.S. 4.3 O 0.1 Br 1.6 , M 5.4 P.S. 4.1 O 0.3 Br 1.6 , M 5.4 P.S. 3.9 O 0.5 Br 1.6 , M 5.4 P.S. 3.65 O 0.75 Br 1.6 , M 5.7 P.S. 4.4 O 0.3 Br 1.3 , M 5.1 P.S. 4.4 O0.3 Br 1.3 and M. 4.8 P.S. 4.1 O 0.3 Br 1.6 where M is as defined herein. For example, the inorganic compound having an argyrodite structure can be selected from inorganic compounds having the formula M 5.4 P.S. 4.1 O 0.3 Br 1.6 where M is as defined herein.

[0043] According to another embodiment of interest, Z is an iodine atom and the alkali metal halide is an alkali metal iodide. For example, an inorganic compound having an argyrodite-type structure can be represented by the formula M 5.4 P.S. 4.3 O 0.1 I 1.6 , M 5.4 P.S. 4.1 O 0.3 I 1.6 , M 5.4 P.S. 3.9 O 0.5 I 1.6 , M 5.4 P.S. 3.65 O 0.75 I 1.6 , M 5.7 P.S. 4.4 O 0.3 I 1.3 , M 5.1 P.S. 4.4 O 0.3 I 1.3 and M. 4.8 P.S. 4.1 O 0.3 I 1.6 where M is as defined herein.

[0044] According to the illustrative embodiment, Z is a combination including chlorine and bromine, and the alkali metal halide is a mixture of alkali metal chloride and alkali metal bromide. For example, an inorganic compound having an argyrodite-type structure can be represented by the formula M 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.6 , M 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 and M. 5.4 P.S. 4.1 O 0.3 Cl 0.6 Br 1.0 where M is as defined herein.

[0045] According to the illustrative example, Z is a combination including chlorine, bromine and iodine, and the alkali metal halide is a mixture of alkali metal chloride, alkali metal bromide and alkali metal iodide. For example, inorganic compounds having an argyrodite-type structure can be represented by the formula M 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 , M 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I 0.1 , M 5.4 P.S. 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 and M. 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.4 I 0.2 where M is as defined herein.

[0046] According to the example under consideration, the alkali metal is lithium, the inorganic compound with argyrodite structure is based on Li2S-P2S5-Li2SO4-LiZ, where Z is a halogen atom selected from F, Cl, Br and I or a combination of at least two of them, and the method comprises a step of direct grinding of a precursor consisting of lithium sulfide (Li2S), lithium sulfate (Li2SO4), phosphorus pentasulfide (P2S5), and lithium halides selected from lithium fluoride (LiF), lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), and mixtures of at least two of them.

[0047] Non-limiting examples of inorganic compounds having an argyrodite-type structure according to formula 1 include compounds of formula Li 5.4 P.S. 4.3 O 0.1 Z 1.6 , Li 5.4 P.S. 4.1 O 0.3 Z 1.6 , Li 5.4 P.S. 3.9 O 0.5 Z 1.6 , Li 5.4 P.S. 3.65 O 0.75 Z 1.6 and Li 5.7 P.S. 4.4 O 0.3 Z 1.3 where Z is as defined herein. Non-limiting examples of inorganic compounds having an argyrodite-type structure according to formula 2 include inorganic compounds having the formula Li 5.1 P.S. 4.4 O 0.3 Z 1.3 and Li 4.8 P.S. 4.1 O 0.3 Z 1.6 where Z is as defined herein.

[0048] According to the example of interest, Z is a chlorine atom and the lithium halide is LiCl. For example, an inorganic compound having an argyrodite structure has the formula Li 5.4 P.S. 4.3 O 0.1 Cl 1.6 , Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 , Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 , Li 5.4 P.S. 3.65 O 0.75 Cl 1.6 , Li 5.7 P.S. 4.4 O 0.3 Cl 1.3 , Li 5.1 P.S. 4.4 O 0.3 Cl 1.3 and Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 The compound can be selected from inorganic compounds having an argyrodite structure.

[0049] According to another example of interest, Z is a bromine atom and the lithium halide is LiBr. For example, an inorganic compound having an argyrodite-type structure is represented by the formula Li 5.4 P.S. 4.3 O 0.1 Br 1.6 , Li 5.4 P.S. 4.1 O 0.3 Br 1.6 , Li 5.4 P.S. 3.9 O 0.5 Br 1.6 , Li 5.4 P.S. 3.65 O 0.75 Br 1.6 , Li 5.7 P.S. 4.4 O 0.3 Br 1.3 , Li 5.1 P.S. 4.4 O 0.3 Br 1.3 and Li 4.8P.S. 4.1 O 0.3 Br 1.6 For example, the inorganic compound having an argyrodite structure may be selected from inorganic compounds having the formula Li 5.4 P.S. 4.1 O 0.3 Br 1.6 The compound may be an inorganic compound having an argyrodite structure.

[0050] According to another example of interest, Z is an iodine atom and the lithium halide is LiI. For example, an inorganic compound having an argyrodite-type structure is represented by the formula Li 5.4 P.S. 4.3 O 0.1 I 1.6 , Li 5.4 P.S. 4.1 O 0.3 I 1.6 , Li 5.4 P.S. 3.9 O 0.5 I 1.6 , Li 5.4 P.S. 3.65 O 0.75 I 1.6 , Li 5.7 P.S. 4.4 O 0.3 I 1.3 , Li 5.1 P.S. 4.4 O 0.3 I 1.3 and Li 4.8 P.S. 4.1 O 0.3 I 1.6 The compound can be selected from inorganic compounds having an argyrodite structure.

[0051] According to the present example, Z is a combination containing chlorine and bromine, and the lithium halide is a mixture of LiCl and LiBr. For example, an inorganic compound having an argyrodite structure has the formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.6 , Li 5.4 P.S. 4.1 O 0.3 Cl0.8 Br 0.8 and Li 5.4 P.S. 4.1 O 0.3 Cl 0.6 Br 1.0 The compound can be selected from inorganic compounds having an argyrodite structure.

[0052] According to the present example, Z is a combination containing chlorine, bromine and iodine, and the lithium halide is a mixture of LiCl, LiBr and LiI. For example, an inorganic compound having an argyrodite structure has the formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 , Li 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I 0.1 , Li 5.4 P.S. 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 and Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.4 I 0.2 The compound can be selected from inorganic compounds having an argyrodite structure.

[0053] According to another example of interest, the method defined herein is carried out in a single step. That is, preferably, the method does not include an annealing step. Alternatively, the method can include an optional low-temperature annealing step. For example, if the method includes an annealing step, the annealing step can be carried out at a maximum temperature of about 400°C, or at a maximum temperature of about 300°C.

[0054] According to another example, the milling step can be performed using a mill, such as a planetary mill. Any known suitable type of mill is contemplated. For example, the milling step can be performed at a rotational speed for a specified time with a ratio of milling beads:precursor that results in an inorganic compound having the desired argyrodite-type structure.

[0055] According to another example, the grinding step can be performed at a rotation speed ranging from about 300 rpm to about 800 rpm, or from about 400 rpm to about 700 rpm, or from about 500 rpm to about 700 rpm. For example, the grinding step can be performed at a rotation speed of about 600 rpm.

[0056] According to another example, the milling step can be carried out for a period ranging from about 5 hours to about 20 hours. For example, the milling step can be carried out for about 10 hours.

[0057] According to another example, the milling step can be performed at a ratio of milling beads:precursor ranging from about 10 to about 30. For example, the milling step can be performed at a ratio of milling beads:precursor of about 30.

[0058] In some examples, the ratio of milling beads:precursor is about 30, and the milling step is carried out for about 10 hours at a rotation speed ranging from about 500 rpm to about 700 rpm to obtain an inorganic compound having the desired argyrodite structure. For example, the milling step is carried out at a rotation speed of about 600 rpm.

[0059] It should be understood that the parameters of the milling step (e.g., rotation speed, milling time, milling bead:precursor ratio, etc.) to obtain an inorganic compound having a desired argyrodite-type structure can be selected and / or optimized depending on the type of mill used.

[0060] In the method defined herein, the use of alkali metal sulfates (e.g. Li2SO4) as precursors may make it possible to obtain argyrodite-type structures without an annealing step or with a low-temperature annealing step. Furthermore, the method defined herein may make it possible to obtain inorganic compounds from different precursors with ionic conductivities substantially similar to those reported for inorganic compounds obtained by conventional methods including an annealing step.

[0061] Certain properties of the inorganic compounds obtained by certain embodiments of the method may also differ from those demonstrated by compounds prepared by conventional methods, for example, by methods using alkali metal oxides (e.g., Li2O) instead of alkali metal sulfates (e.g., Li2SO4) as precursors. For example, according to some embodiments, the compounds obtained herein may exhibit higher electrochemical stability, lower H2S release, higher critical current density or lower polarization compared to conventionally obtained compounds. The inorganic compounds described herein according to certain embodiments include: 6 Li or 31 Higher purity of the argyrodite structure by P NMR, and / or 31 A reduction in the relative intensities of peaks associated with the PO2S2, PO3S and / or PO4 groups in P NMR can be demonstrated. For example, the relative intensities of the PO2S2, PO3S and PO4 peaks can be less than 1.5, less than 0.8 and less than 0.3, respectively.

[0062] The present technology also relates to inorganic compounds having an argyrodite-type structure as defined herein, obtainable by the process as defined herein.

[0063] The present technology also relates to electrochemically active materials and electrode materials comprising inorganic compounds having an argyrodite-type structure as defined herein or obtainable by the methods defined herein.

[0064] According to one example, inorganic compounds having an argyrodite-type structure as defined herein can be present as additives in electrode materials and / or as coating materials, for example, inorganic compounds having an argyrodite-type structure can form a coating layer on the surface of an electrochemically active material.

[0065] According to another example, the electrode material is a positive electrode material, and the electrochemically active material is selected from metal oxides, metal sulfides, metal oxysulfides, metal phosphates, metal fluorophosphates, metal oxyfluorophosphates, metal sulfates, metal halides (e.g., metal fluorides), sulfur, selenium, and combinations of at least two of them. According to another example, the metal of the electrochemically active material is selected from titanium (Ti), iron (Fe), manganese (Mn), vanadium (V), nickel (Ni), cobalt (Co), aluminum (Al), chromium (Cr), copper (Cu), zirconium (Zr), niobium (Nb), molybdenum (Mo), tungsten (W), and combinations thereof, if applicable. The electrochemically active material can further include an alkali metal or alkaline earth metal, such as lithium (Li), sodium (Na), potassium (K), or magnesium (Mg), as required.

[0066] Non-limiting examples of electrochemically active materials include lithium metal phosphates, complex oxides, such as LiM'PO4 (wherein M' is Fe, Ni, Mn, Co, or a combination thereof), LiV3O8, V2O5, LiMn2O4, LiM''O2 (wherein M'' is Mn, Co, Ni, or a combination thereof), Li(NiM''')O2 (wherein M''' is Mn, Co, Al, Fe, Cr, Ti, or Zr, or a combination thereof), and combinations thereof, where compatible.

[0067] According to a subject example, the electrochemically active material is an oxide of the above. For example, the electrochemically active material can be lithium manganese oxide, where the manganese can be partially replaced by a second transition metal, such as lithium nickel manganese cobalt oxide (NMC). According to one subject embodiment, the electrochemically active material is LiNi 0.6 Mn 0.2 Co 0.2 O2(NMC622).

[0068] According to another example, the electrode material is a negative electrode material and the electrochemically active material is selected from the group consisting of non-alkali and non-alkaline earth metals (e.g., indium (In), germanium (Ge) and bismuth (Bi)), intermetallic compounds (e.g., SnSb, TiSnSb, CuSb, AlSb, FeSb2, FeSn2 and CoSn2), metal oxides, metal nitrides, metal phosphides, metal phosphates (e.g., LiTi2(PO4)3), metal halides (e.g., metal fluorides), metal sulfides, metal oxysulfides, carbon (e.g., graphite, graphene, reduced graphene oxide, hard carbon, soft carbon, exfoliated graphite and amorphous carbon), silicon (Si), silicon-carbon composites (Si-C), silicon oxides (SiO x ), silicon oxide-carbon composite (SiO x -C), tin (Sn), tin-carbon composite (Sn-C), tin oxide (SnO x ), tin oxide-carbon composite (SnO x For example, the metal oxide is selected from the formula M"" b O cExamples of suitable oxides include, for example, MoO3, MoO2, MoS2, V2O5, and TiNb2O7, spinel oxides (for example, NiCo2O4, ZnCo2O4, MnCo2O4, CuCo2O4, and CoFe2O4), and LiM'''O (wherein M''''' is Ti, Mo, Mn, Ni, Co, Cu, V, Fe, Zn, Nb, or a combination thereof, and b and c are numbers such that the ratio c:b is in the range of 2 to 3) (for example, MoO3, MoO2, MoS2, V2O5, and TiNb2O7), spinel oxides (for example, NiCo2O4, ZnCo2O4, MnCo2O4, CuCo2O4, and CoFe2O4), and LiM'''O (wherein M''''' is Ti, Mo, Mn, Ni, Co, Cu, V, Fe, Zn, Nb, or a combination thereof) (for example, lithium titanate (Li4Ti5O 12 ) or lithium molybdenum oxide (Li2Mo4O 13 The compound can be selected from the following compounds:

[0069] According to another example, the electrochemically active material can be doped with other elements present in smaller amounts, if necessary, for example to adjust or optimize its electrochemical properties. The electrochemically active material can be doped by partial substitution of metals with other ions. For example, the electrochemically active material can be doped with transition metals (e.g., Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, W or Y) and / or metals other than transition metals (e.g., Mg, Al or Sb).

[0070] According to another example, the electrochemically active material can be in the form of particles (e.g., microparticles and / or nanoparticles) that can be newly formed or derived from commercial sources. For example, the electrochemically active material can be in the form of particles coated with a layer of a coating material. The coating material can be an electronically conductive material, such as a conductive carbon coating. Alternatively, the coating material can make it possible to substantially reduce the interfacial reaction at the interface between the electrochemically active material and the electrolyte, for example, a solid electrolyte, in particular a solid electrolyte of inorganic ceramic type based on sulfides or oxysulfides (for example, based on inorganic compounds having an argyrodite-type structure as defined herein). For example, the coating material can be selected from Li2SiO3, LiTaO3, LiAlO2, Li2O-ZrO2, LiNbO3, combinations thereof, if applicable, and other similar materials. According to one embodiment of interest, the coating material comprises LiNbO3.

[0071] According to another example, the electrode material defined herein further comprises an electronically conductive material. Non-limiting examples of electronically conductive materials include carbon sources such as carbon black (e.g., Ketjen™ carbon and Super P™ carbon), acetylene black (e.g., Shawinigan carbon and Denka™ carbon black), graphite, graphene, carbon fibers (e.g., vapor grown carbon fibers (VGCF)), carbon nanofibers, carbon nanotubes (CNTs), and combinations of at least two of them. According to one embodiment of interest, the electronically conductive material is a mixture of Li400 carbon black (Denka™) and VGCF (preferably in a weight ratio ranging from 65:35 to 85:15).

[0072] According to another example, the electrode material defined herein further comprises an additive. For example, the additive is selected from inorganic ion-conducting materials, inorganic materials, glasses, glass-ceramics, ceramics (including nanoceramics (such as Al2O3, TiO2, SiO2 and other similar compounds)), salts (e.g., lithium salts), and combinations of at least two of them. For example, the additive can be an inorganic ion conductor selected from LISICON, thio-LISICON, argyrodite, garnet, NASICON, perovskite, oxides, sulfides, phosphides, fluorides, sulfur halides, phosphates, thiophosphates, and combinations of at least two of them, in crystalline and / or amorphous form.

[0073] According to another example, the electrode material defined herein further comprises a binder. For example, the binder is selected for its compatibility with the various components of the electrochemical cell. Any known compatible binder is contemplated. For example, the binder may be selected from polymeric binders of polyether, polycarbonate or polyester type, fluorinated polymers and water-soluble binders. According to one example, the binder is a fluorinated polymer such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE). According to another example, the binder is a water-soluble binder such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), hydrogenated NBR (HNBR), epichlorohydrin rubber (CHR) or acrylic acid rubber (ACM), optionally including a thickener such as carboxymethylcellulose (CMC) or a polymer such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMMA), or a combination thereof. According to another example, the binder is a polymeric binder of polyether type. For example, the polyether type polymer binders may be linear, branched and / or crosslinked and may be based on polyethylene oxide (PEO), poly(propylene oxide) (PPO), or combinations thereof (such as EO / PO copolymers) and may optionally contain crosslinkable units. For example, the crosslinkable segment of the polymer may be a polymer segment that contains at least one functional group capable of multi-dimensional crosslinking by irradiation or heat treatment.

[0074] The present technology also relates to an electrode comprising the electrode material defined herein. According to one example, the electrode can be on a current collector (e.g., aluminum or copper foil). Alternatively, the electrode can be self-supporting.

[0075] The present technology also relates to an electrolyte comprising an inorganic compound having an argyrodite-type structure as defined herein or obtainable by the method defined herein.

[0076] According to one example, the electrolyte can be selected for its compatibility with the various components of the electrochemical cell. Any compatible type of electrolyte is contemplated. According to one example, the electrolyte is a liquid electrolyte comprising a salt in a solvent. According to an alternative, the electrolyte is a gel electrolyte comprising a salt in a solvent and optionally in a solvating polymer. According to another alternative, the electrolyte is a solid polymer electrolyte comprising a salt in a solvating polymer. According to another alternative, the electrolyte comprises an inorganic solid electrolyte material, for example, the electrolyte can be a ceramic type inorganic solid electrolyte. According to another alternative, the electrolyte is a polymer-ceramic hybrid solid electrolyte.

[0077] According to another example, the salt, when present in the electrolyte, can be an ionic salt, such as a lithium salt. Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNO3), lithium chloride. (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiSO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CO2)2] (LiBBB), and combinations of at least two thereof.

[0078] According to another example, the solvent, when present in the electrolyte, can be a non-aqueous solvent. Non-limiting examples of solvents include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and vinylene carbonate (VC); acyclic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC); lactones such as γ-butyrolactone (γ-BL) and γ-valerolactone (γ-VL); 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (D acyclic ethers such as ethylene glycol (EE), ethoxymethoxyethane (EME), trimethoxymethane, and ethyl monoglyme; cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, and dioxolane derivatives; and other solvents such as dimethylsulfoxide, formamide, acetamide, dimethylformamide, acetonitrile, propylnitrile, nitromethane, phosphoric acid triesters, sulfolane, methylsulfolane, propylene carbonate derivatives, and mixtures thereof.

[0079] According to another example, the electrolyte is a gel electrolyte or a gel polymer electrolyte.The gel polymer electrolyte can include, for example, a polymer precursor and a salt (for example, the salt defined above), a solvent (for example, the solvent defined above), and if necessary, a polymerization initiator and / or a cross-linking initiator.Examples of gel electrolytes include, but are not limited to, those described in PCT patent applications published under WO2009 / 111860 (Zaghib et al.) and WO2004 / 068610 (Zaghib et al.).

[0080] According to another example, the gel electrolyte or liquid electrolyte defined above can also be impregnated with a separator, such as a polymer separator. Examples of separators include, but are not limited to, separators made of polyethylene (PE), polypropylene (PP), cellulose, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and polypropylene-polyethylene-polypropylene (PP / PE / PP). For example, the separator is a commercially available polymer separator of the Celgard™ type.

[0081] According to another example, the electrolyte is a solid polymer electrolyte. For example, the solid polymer electrolyte can be selected from any known solid polymer electrolyte and can be selected for its compatibility with various elements of the electrochemical cell. The solid polymer electrolyte generally includes a salt and one or more solid polar polymers, which are optionally crosslinked. A polyether type polymer, such as one based on polyethylene oxide (POE), can be used, although several other compatible polymers are also known for the preparation of solid polymer electrolytes and are also contemplated. The polymer can be crosslinked. Examples of such polymers include branched polymers, such as star or comb polymers, such as those described in the PCT patent application published under WO2003 / 063287 (Zaghib et al.).

[0082] According to another example, the solid polymer electrolyte can include a block copolymer composed of at least one lithium ion solvating segment and, optionally, at least one crosslinkable segment. Preferably, the lithium ion solvating segment comprises a repeat unit of formula I: [ka] (In the formula, R is a hydrogen atom or a C1-C 10 Alkyl or -(CH2-OR a R b ) group, Ra is (CH2-CH2-O) y and R b is a hydrogen atom and C1-C 10 alkyl groups, x is an integer selected from the range of 10 to 200,000; y is an integer selected from the range of 0 to 10. The polymer is selected from homopolymers or copolymers having the following formula:

[0083] According to another example, the crosslinkable segment of the copolymer is a polymer segment that contains at least one functional group that is multi-dimensionally crosslinkable by irradiation or heat treatment.

[0084] When the electrolyte is a liquid electrolyte, a gel electrolyte or a solid polymer electrolyte, the inorganic compound having an argyrodite-type structure as defined herein can be present as an additive in the electrolyte.

[0085] When the electrolyte is a polymer-ceramic hybrid solid electrolyte or a ceramic-type inorganic solid electrolyte, an inorganic compound having an argyrodite-type structure as defined herein can be present as the inorganic solid electrolyte (ceramic) material.

[0086] According to another example, the electrolyte may optionally include additional components, such as ionically conductive materials, inorganic particles, glass or ceramic particles, and other additives of the same type. The additional components may be selected for their compatibility with the various elements of the electrochemical cell. According to one example, the additional components may be substantially dispersed in the electrolyte. Alternatively, the additional components may be present in a separate layer.

[0087] The present technology also relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein at least one of the positive electrode or the negative electrode is as defined herein or comprises an electrode material defined herein.

[0088] According to an example, the negative electrode is as defined herein or comprises an electrode material as defined herein. For example, the electrochemically active material of the negative electrode can be selected for its electrochemical compatibility with the various elements of the electrochemical cell as defined herein. For example, the electrochemically active material of the negative electrode material can have a substantially lower oxidation-reduction potential than the electrochemically active material of the positive electrode.

[0089] According to another example, the positive electrode is as defined herein or includes the electrode material defined herein, and the negative electrode includes an electrochemically active material selected from any known compatible electrochemically active material. For example, the electrochemically active material of the negative electrode can be selected for its electrochemical compatibility with the various elements of the electrochemical cell defined herein. Non-limiting examples of the electrochemically active material of the negative electrode include alkali metals, alkaline earth metals, alloys including at least one alkali metal or alkaline earth metal, non-alkali metals and non-alkaline earth metals (e.g., indium (In), germanium (Ge) and bismuth (Bi)), and intermetallic alloys or compounds (e.g., SnSb, TiSnSb, Cu2Sb, AlSb, FeSb2, FeSn2 and CoSn2). For example, the electrochemically active material of the negative electrode can be in the form of a film. According to one embodiment of interest, the electrochemically active material of the negative electrode can include a film of metallic lithium or a film of an alloy including or based on metallic lithium.

[0090] According to another example, the positive electrode may be pre-lithiated and the negative electrode may be substantially or completely free of lithium initially (i.e., before cycling the electrochemical cell). The negative electrode may be lithiated in situ during cycling of the electrochemical cell, particularly during the first charge. According to one example, metallic lithium may be deposited in situ on a current collector (e.g., a copper current collector) during cycling of the electrochemical cell, particularly during the first charge. According to another example, an alloy containing metallic lithium may be formed on a surface of a current collector (e.g., an aluminum current collector) during cycling of the electrochemical cell, particularly during the first charge. It is understood that the negative electrode may be formed in situ during cycling of the electrochemical cell, particularly during the first charge.

[0091] According to another example, the positive electrode and the negative electrode are both as defined herein or both include an electrode material as defined herein.

[0092] The present technology also relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the electrolyte is as defined herein.

[0093] The present technology also relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the electrolyte is as defined herein and at least one of the positive electrode or the negative electrode is as defined herein or comprises an electrode material as defined herein.

[0094] According to one example, the positive electrode is as defined herein or comprises an electrode material defined herein.

[0095] The present technology also relates to a battery comprising at least one electrochemical cell as defined herein. For example, the battery can be a primary battery or a secondary battery. According to one example, the battery is selected from the group consisting of a lithium battery, a lithium-ion battery, a sodium battery, a sodium-ion battery, a magnesium battery, a magnesium-ion battery, a potassium battery and a potassium-ion battery. According to a variant of interest, the battery is an all-solid-state battery.

[0096] According to one example, the use of alkali metal sulfates (e.g., Li2SO4) as precursors in the methods defined herein may allow for reduced production costs by using less Li2S and / or no annealing step or reduced annealing temperature.

[0097] According to another example, the method defined herein may make it possible to obtain inorganic compounds from different precursors with ionic conductivities substantially similar to those reported for inorganic compounds obtained by conventional methods, including an annealing step.

[0098] According to another example, the method defined herein may make it possible to obtain inorganic compounds with improved electrochemical stability.

[0099] According to another example, the method defined herein may make it possible to obtain inorganic compounds with improved safety, for example by substantially reducing the amount of H2S generated by exposure of the inorganic compounds to moisture or ambient air.

[0100] According to another example, the method defined herein may allow for a higher critical current density and therefore greater safety when contacting metallic or metal alloy negative electrodes. EXAMPLES

[0101] The following examples are for illustrative purposes and should not be construed as further limiting the scope of the contemplated invention, which examples will be better understood with reference to the accompanying drawings.

[0102] Unless otherwise indicated, all numbers used herein expressing amounts of components, preparation conditions, concentrations, properties, and the like, should be understood to be modified in all cases by the term "about". At the very least, each numerical parameter should be interpreted in light of the number of significant digits reported and by applying ordinary rounding techniques. Thus, unless otherwise indicated to the contrary, the numerical parameters set forth herein are approximations that may vary depending on the properties sought to be obtained. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the embodiments are approximations, the numerical values ​​set forth in the following examples are reported as precisely as possible. However, any numerical value inherently contains certain errors resulting from variations in experiments, testing measurements, statistical analyses, and the like. Example 1 Synthesis of argyrodite

[0103] Formula Li 5.4 P.S. 4.3 O 0.1 Cl 1.6 , Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 , Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 , Li 5.4 P.S. 3.65 O 0.75 Cl 1.6 , Li 5.7 P.S. 4.4 O 0.3 Cl 1.3 , Li 5.1 P.S. 4.4 O 0.3 Cl 1.3 , Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 , Li 5.4PS 4.4 Cl 1.6 、Li 5.4 PS 4.1 O 0.3 Cl 1.6 、Li 5.4 PS 3.9 O 0.5 Cl 1.6 、Li 5.4 PS 4.1 O 0.3 Br 1.6 、Li 5.4 PS 4.1 O 0.3 Cl 1.0 Br 0.6 、Li 5.4 PS 4.1 O 0.3 Cl 0.8 Br 0.8 、Li 5.4 PS 4.1 O 0.3 Cl 0.6 Br 1.0 、Li 5.4 PS 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 、Li 5.4 PS 4.1 O 0.3 Cl 0.75 Br 0.75 I 0.1 、Li 5.4 PS 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 、Li 5.4 PS 4.1 O 0.3 Cl 1.0 Br 0.4 I 0.2Inorganic compounds with argyrodite-type structure of Li6PS5Cl were prepared completely in a glove box under inert atmosphere (H2O<0.1 ppm; O2<0.1 ppm) by solid-state reaction method without heat treatment. The inorganic compounds were obtained by grinding method from precursors Li2S, P2S5, Li2SO4 or Li2O and at least one Li halide (LiCl, LiBr and / or LiI) to obtain powders with the desired stoichiometry according to the following reaction scheme: (3,5-y / 4-tzw)Li2S+y / 4 Li2SO4+1 / 2 P2S5+t LiCl+z LiBr+w LiI → Li 7-t-z-w P.S. 6-t-y-z-w O y Cl t Br z I w +y S formula (3) (3,5-5 / 4y-t)Li2S+y / 4 Li2SO4+1 / 2 P2S5+t LiCl →Li 7-t-2y P.S. 6-t-y O y Cl t Formula (4) (3,5-yt)Li2S+y Li2O+1 / 2 P2S5+t LiCl → Li 7-t P.S. 6-t-y O y Cl t Formula (5)

[0104] The powder milling was carried out by two different methods. First method for grinding powders (Method 1):

[0105] The powder was milled using a PULVERISETTE7 planetary mill. 1.7 g of powder and 15 yttria-zirconia milling beads with a diameter of 10 mm (beads:powder=30 mass ratio) were placed in a 45 mL yttria-zirconia milling jar. The powder was milled for about 10 hours at a speed of about 600 rpm to produce an inorganic compound having an argyrodite-type structure. Second method for grinding powders (Method 2):

[0106] The powder was milled using a PM100 planetary mill. 14 g of powder and 16 yttria-zirconia milling beads with a diameter of 20 mm (mass ratio of beads:powder=30) were placed in a 250 mL yttria-zirconia milling jar. The powder was milled for about 10 hours at a speed of about 650 rpm to produce an inorganic compound having an argyrodite-type structure. Formula Li 5.4 P.S. 4.3 O 0.1 Cl 1.6 Argyrodite (Argyrodite 1):

[0107] Formula Li 5.4 P.S. 4.3 O 0.1 Cl 1.6 was obtained from the precursors Li2S, P2S5, LiCl and Li2SO4 by Method 1 of this Example, according to Formula 3 (t=1.6; z=0; w=0; and y=0.1). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 Argyrodite (Argyrodite 2):

[0108] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl and Li2SO4 according to formula 3 (t=1.6; z=0; w=0; and y=0.3). Formula Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 Argyrodite (Argyrodite 3):

[0109] Formula Li 5.4 P.S. 3.9 O 0.5 Cl 1.6was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl and Li2SO4 according to formula 3 (t=1.6; z=0; w=0; and y=0.5). Formula Li 5.4 P.S. 3.65 O 0.75 Cl 1.6 Argyrodite (Argyrodite 4):

[0110] Formula Li 5.4 P.S. 3.65 O 0.75 Cl 1.6 was obtained from the precursors Li2S, P2S5, LiCl and Li2SO4 by Method 1 of this Example, according to Formula 3 (t=1.6; z=0; w=0; and y=0.75). Formula Li 5.7 P.S. 4.4 O 0.3 Cl 1.3 Argyrodite (Argyrodite 5):

[0111] Formula Li 5.7 P.S. 4.4 O 0.3 Cl 1.3 was obtained from the precursors Li2S, P2S5, LiCl and Li2SO4 by Method 1 of this Example, according to Formula 3 (t=1.3; z=0; w=0; and y=0.3). Formula Li 5.1 P.S. 4.4 O 0.3 Cl 1.3 Argyrodite (Argyrodite 6):

[0112] Formula Li 5.1 P.S. 4.4 O 0.3 Cl 1.3 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl and Li2SO4 according to formula 4 (t=1.3; z=0; w=0; and y=0.3). Formula Li 4.8 P.S. 4.1O 0.3 Cl 1.6 Argyrodite (Argyrodite 7):

[0113] Formula Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl and Li2SO4 according to formula 4 (t=1.6; z=0; w=0; and y=0.3). Formula Li 5.4 P.S. 4.4 Cl 1.6 Argyrodite (Argyrodite 8) (Comparative Example):

[0114] Formula Li 5.4 P.S. 4.4 Cl 1.6 was obtained for comparative purposes by method 1 of this example from the precursors Li2S, P2S5 and LiCl, according to formula 3 (t=1.6; z=0; w=0; and y=0). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 Argyrodite (Argyrodite 9) (Comparative Example):

[0115] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 was obtained for comparative purposes by method 1 of this example from the precursors Li2S, P2S5, LiCl and Li2O according to formula 5 (t=1.6; z=0; w=0; and y=0.3). Formula Li 5.4 P.S. 3.9 O 0.5 Cl 1.6 Argyrodite (Argyrodite 10) (Comparative Example):

[0116] Formula Li 5.4 P.S. 3.9 O 0.5 Cl 1.6was obtained for comparative purposes by method 1 of this example from the precursors Li2S, P2S5, LiCl and Li2O according to formula 5 (t=1.6; z=0; w=0; and y=0.5). Argyrodite of formula Li6PS5Cl (Argyrodite 11) (Comparative Example):

[0117] An inorganic compound having an argyrodite-type structure of formula Li6PS5Cl was obtained for comparative purposes from the precursors Li2S, P2S5 and LiCl by method 1 of this example, according to formula 3 (t=1.0; z=0; w=0; and y=0). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.6 Argyrodite (Argyrodite 12):

[0118] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.6 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr and Li2SO4 according to formula 3 (t=1.0; z=0.6; w=0; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 Argyrodite (Argyrodite 13):

[0119] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr and Li2SO4 according to formula 3 (t=0.8; z=0.8; w=0; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3Cl 0.6 Br 1.0 Argyrodite (Argyrodite 14):

[0120] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.6 Br 1.0 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr and Li2SO4 according to formula 3 (t=0.6; z=1; w=0; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Br 1.6 Argyrodite (Argyrodite 15):

[0121] Formula Li 5.4 P.S. 4.1 O 0.3 Br 1.6 was obtained by method 1 of this example from precursors Li2S, P2S5, LiBr and Li2SO4 according to formula 3 (t=0; w=0; z=1.6; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 Argyrodite (Argyrodite 16):

[0122] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 was obtained from the precursors Li2S, P2S5, LiCl, LiBr, LiI and Li2SO4 by Method 1 of this Example, according to Formula 3 (t=1.0; z=0.5; w=0.1; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I0.1 Argyrodite (Argyrodite 17):

[0123] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.75 Br 0.75 I 0.1 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr, LiI and Li2SO4 according to formula 3 (t=0.75; z=0.75; w=0.1; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 Argyrodite (Argyrodite 18):

[0124] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.7 Br 0.7 I 0.2 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr, LiI and Li2SO4 according to formula 3 (t=0.7; z=0.7; w=0.2; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.4 I 0.2 Argyrodite (Argyrodite 19):

[0125] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.4 I 0.2 was obtained by method 1 of this example from precursors Li2S, P2S5, LiCl, LiBr, LiI and Li2SO4 according to formula 3 (t=1.0; z=0.4; w=0.2; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 Argyrodite (Argyrodite 20):

[0126] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 was obtained from the precursors Li2S, P2S5, LiCl and Li2SO4 by Method 2 of this Example, according to Formula 3 (t=1.6; z=0; w=0; and y=0.3). Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 Argyrodite (Argyrodite 21):

[0127] Formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 was obtained by method 2 of this example from precursors Li2S, P2S5, LiCl, LiBr and Li2SO4 according to formula 3 (t=0.8; z=0.8; w=0; and y=0.3). Example 2 X-ray diffraction (XRD) characterization of inorganic compounds with argyrodite-type structure

[0128] The crystal structure of the argyrodite prepared in Example 1 was investigated by XRD. The analysis was carried out entirely in an anhydrous chamber, and the X-ray spectrum was obtained using a Rigaku MiniFlex™ X-ray diffractometer equipped with a cobalt X-ray source.

[0129] A pellet was prepared by compressing 80 mg of the argyrodite powder prepared in Example 1. The pellet was then placed in a sealed sample holder that was closed in a glove box under an inert atmosphere.

[0130] In the X-ray diffraction patterns presented in Figures 1-6, the peaks corresponding to Li3PO4, Li2S and LiCl impurities are identified by solid, dashed and two-dot chain lines, respectively. The "D" peak originates from the dome used in the XRD analysis. The other peaks correspond to the argyrodite-type structure.

[0131] Figure 1 represents the X-ray diffraction patterns obtained for the argyrodites (Argyrodites 1-4 and 8). The X-ray diffraction patterns represented in Figure 1 show that the argyrodite-type structure is indeed obtained for all compositions. In the case of the most oxygen-rich compositions (y>0.3) (Argyrodites 3 and 4), the presence of substantially higher amounts of impurities (LiCl, Li2S and Li3PO4) can be observed.

[0132] Figure 2 represents the X-ray diffraction patterns obtained for argyrodites 2 and 5-7. Figure 2 shows that in the case of t=1.3 and y=0.3 (argyrodites 5 and 6) and that in the case of the two syntheses (formulas 3 and 4), the argyrodite structure was indeed obtained. In Figure 2, it can be observed that there is less residual Li2S present in the structure of argyrodite 6 than in the structure of argyrodite 5. Figure 2 also shows that the Li2S in the structure of formula Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 Figure 1 shows the decomposition of an argyrodite structure (Argyrodite 7) at (t=1.6 and y=0.3). Substantially larger amounts of residual LiCl can be observed, but no trace of Li2S can be observed. This indicates that argyrodite structures containing small amounts of lithium may lead to a mixture of argyrodite and parasitic phases (e.g., LiCl).

[0133] FIG. 3 represents the X-ray diffraction patterns of argyrodites obtained from Li2SO4 (argyrodites 2 and 3) and Li2O (argyrodites 9 and 10) precursors. FIG. 3 shows that for an oxygen content of 0.3 (argyrodites 2 and 9), there is no observable significant difference in the structure of the inorganic argyrodites obtained from the two different precursors. However, for an oxygen content of 0.5, the argyrodite prepared from Li2O (argyrodite 10) contains substantially more impurities (among others, LiCl) and has a substantially less well-defined structure compared to the argyrodite prepared from Li2SO4 (argyrodite 3). Thus, substantially purer oxidized argyrodites can be obtained from the Li2SO4 precursor over a wide composition range compared to the commonly used Li2O precursor.

[0134] Figure 4 presents the X-ray diffraction patterns of argyrodites obtained from the Li2SO4 precursor and a mixture of halides containing LiCl and LiBr (argyrodite 12-14) compared to the X-ray diffraction patterns of the same compositions obtained from LiCl (argyrodite 2) or LiBr (argyrodite 15). Figure 4 shows that the argyrodite structure is well preserved, independent of the Br and Cl content. The peak positions decrease as the Br content increases. This can be attributed to an increase in the lattice parameter, a phenomenon known in the literature.

[0135] Figure 5 shows the X-ray diffraction patterns of argyrodites (argyrodites 16-19) obtained from the Li2SO4 precursor and a mixture of halides including LiCl, LiBr, and LiI. Figure 5 shows that the argyrodite structure is well preserved even when a mixture of the three halides is used.

[0136] Thus, regardless of composition and mixture of halides, compounds with the oxidized argyrodite structure can be obtained by oxidation from the Li2SO4 precursor.

[0137] Figure 6 shows the X-ray diffraction patterns of argyrodites 2 and 13 obtained from the Li2SO4 precursor in small volume jars (according to method 1 presented in Example 1) and of argyrodites 20 and 21 obtained from the Li2SO4 precursor in larger volume jars (according to method 2 presented in Example 1). The compositions of argyrodites 2 and 20 are similar, as are the compositions of argyrodites 13 and 21. Figure 5 shows that the argyrodite structure is well preserved, regardless of the composition of the argyrodite and regardless of the amount synthesized, thus demonstrating that the described method can be applied on an industrial scale. Example 3 Nuclear magnetic resonance (NMR) characterization of inorganic compounds with the argyrodite-type structure.

[0138] The composition of the argyrodite prepared in Example 1 was examined by NMR. 6 Li NMR) and phosphorus ( 31 Nuclear magnetic resonance spectra (P NMR) were obtained by MAS (magic angle spinning) technique using a Bruker Avance NEO 500 MHz spectrometer equipped with a 4 mm triple resonance probe at a maximum magic angle spinning rate of 15 kHz.

[0139] 7 and 8 show the compositions Li2SO4 (Argyrodite 2) and Li2O (Argyrodite 9) obtained from the precursors, respectively. 5.4 P.S. 4.1 O 0.3 Cl 1.6 The results obtained for argyrodite are 6 Li NMR and 31 P NMR spectrum is shown.

[0140] For two argyrodites (argyrodites 2 and 9), the 6 The major peak in the Li NMR spectrum corresponds to argyrodite, while the secondary peak corresponds to LiCl residues.

[0141] For argyrodites 2 and 9, the 31 The major peak in the P NMR spectrum corresponds to argyrodite, while the secondary peak corresponds to P2S6 4- , corresponding to the PO2S2, PO3S and PO4 phases. 31 The relative intensities of the P NMR peaks are shown in Table 1. [Table 1]

[0142] The relative intensities of the peaks presented in Table 1 show that the use of Li2SO4 (Argyrodite 2) as precursor makes it possible to significantly reduce the formation of PO2S2, PO3S and PO4 secondary phases compared to the use of Li2O (Argyrodite 9). It can thus be observed that oxygen is better incorporated into the argyrodite structure thanks to the Li2SO4 precursor, thus resulting in less formation of further phases. This makes it possible to distinguish argyrodite synthesized from Li2SO4 from argyrodite prepared from Li2O or any other oxygen source as precursor.

[0143] 9 and 10 show, respectively, the Li2SO4 precursor-derived cations of formula Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 obtained for argyrodite (argyrodite 7). 6 Li NMR and 31 P NMR spectrum is shown.

[0144] As shown in Figure 9 6 In the Li NMR spectrum, a peak at 1.2 ppm corresponding to an argyrodite phase with six lithiums and one chlorine, a second peak at 0.2 ppm corresponding to an argyrodite phase with a structure having an excess of chlorine, and a third peak at -1.1 ppm corresponding to LiCl can be observed.

[0145] As shown in Figure 1031 In the P NMR spectrum, the main peaks correspond to argyrodite, as well as P2S6 4- , PO2S2 and PO3S phases can be observed. Figure 10 also represents a zoom-in of the main peak, showing that it splits into three peaks corresponding to one (P1), two (P2) and three (P3) chlorines in the secondary phosphorus structures. The simultaneous excess of P1 and P3 confirms the presence of two types of argyrodite, with low and high percentages of chlorine.

[0146] Thus, a substantial reduction in the lithium content can result in the presence of at least two argyrodite phases.

[0147] 11 and 12 show, respectively, the Li2SO4 precursor-derived cations of formula Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 (Argyrodite 13), and the formula Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 The results obtained for the argyrodite (argyrodite 16) 6 Li NMR and 31 The P NMR spectrum is shown in Figure 11. 6 The major peak in the Li NMR spectrum corresponds to argyrodite. 31 In the P NMR spectrum, the main peaks correspond to argyrodite, as well as P2S6 4- and the presence of weak secondary peaks corresponding to the PO2S2 phase can be observed, which confirms the results obtained by X-ray diffraction, i.e., the pure oxidized argyrodite phase was obtained from Li2SO4, independent of the halide composition. Example 4 Evolution of H2S from inorganic compounds with argyrodite-type structures upon exposure to air

[0148] A safety test was conducted to evaluate the effect of argyrodite on H2S generation. Approximately 10 mg (± 3 mg) of argyrodite powder was placed in a sealed cell under an inert atmosphere.

[0149] An air stream was introduced into the sealed cell at a flow rate of approximately 0.3 L / min at a controlled temperature of approximately 24.5° C. (±0.5° C.) and a controlled humidity of 50% (±5%). A previously calibrated multi-gas detector (MSA ALTAIR™ 5X) placed at the cell outlet was used to measure the concentration of evolved H2S gas approximately every 15 seconds. From these data, the evolved volume of H2S gas, normalized by the mass of argyrodite, was calculated.

[0150] The results of these analyses are presented in Figure 13. Figure 13 shows the results of the analysis of Argyrodite 2 (Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 )(dotted line), 7(Li 4.8 P.S. 4.1 O 0.3 Cl 1.6 )(dot-dash line), 8(Li 5.4 P.S. 4.4 Cl 1.6 ) (dashed line), 11(Li6PS5Cl) (solid line), 13(Li 5.4 P.S. 4.1 O 0.3 Cl 0.8 Br 0.8 ) (dashed line) and 16(Li 5.4 P.S. 4.1 O 0.3 Cl 1.0 Br 0.5 I 0.1 3 shows a graph of the volume of H2S gas evolved (mL / g) per gram of Argyrodite powder versus time (hours) for the Argyrodite powder (small dashed line).

[0151] The conventional argyrodite of the Li6PS5Cl type (Argyrodite 11) is Li 5.4 P.S. 4.4 Cl 1.6It can be observed that the Li2SO4 precursor-based argyrodites evolve substantially larger volumes of H2S gas than the chlorine-doped argyrodite of type 8 (Argyrodite 8), demonstrating the safety benefits of doping with chlorine. Argyrodites based on the Li2SO4 precursor also evolve at a rate of 100% compared to Argyrodite Li 5.4 P.S. 4.1 O 0.3 Cl 1.6 It can also be observed that, as in the case of (Argyrodite 2), it is possible to reduce the volume of H2S gas. The addition of bromine and / or iodine from the previous composition, while maintaining the same oxygen and lithium content, also makes it possible to reduce the H2S evolution. Finally, FIG. 13 shows that the argyrodite-type structure (Argyrodite 7), which is significantly less lithium, produced from the Li2SO4 precursor, makes it possible to further reduce the volume of H2S gas evolved and therefore improve safety, while also reducing production costs by using less Li2S and by having no or reduced annealing steps. Example 5 Ionic conductivity of inorganic compounds with argyrodite-type structure a) Preparation of a symmetric cell for ionic conductivity measurements

[0152] To measure the ionic conductivity of the inorganic compound having an argyrodite-type structure prepared in Example 1, a symmetric cell was assembled according to the following procedure.

[0153] A pellet was prepared by compressing 160 mg of powder of the inorganic compound having an argyrodite-type structure prepared in Example 1 between two stainless steel electrodes under a pressure of 360 MPa. The pellet placed between the two stainless steel electrodes was then assembled into a sealed conductivity cell, which was closed in a glove box under an inert atmosphere maintained at a pressure of 20 MPa.

[0154] A symmetric cell was assembled with the configuration shown in Table 2. [Table 2]

[0155] b) Measurement of ionic conductivity in symmetric cells Ionic conductivity measurements of the symmetric cell constructed in Example 5(a) were performed using a VMP-300 multichannel potentiostat (BioLogic) at temperatures ranging from -10°C to 70°C (increasing and decreasing temperatures in 10°C increments), at an amplitude of 50 mV, and at frequencies ranging from 7 MHz to 200 mHz.

[0156] Each ionic conductivity measurement was taken after about 1 hour of oven temperature stabilization at that temperature. The ionic conductivity was estimated as a function of the equivalent circuit used to estimate the resistance associated with the measured pellet. Straight lines were obtained for the symmetric cell prepared in Example 5(a). The slopes of these lines correspond to the activation energy, which has a value of about 0.3 eV.

[0157] Figure 14 shows the ionic conductivity results measured as a function of temperature for cells 1 (circles), 2 (triangles), 3 (diamonds), 4 (stars) and 8 (squares). In Figure 14, it can be observed that the ionic conductivity of the most oxygen-deficient argyrodite (y≦0.3) (cells 1 and 2) is similar to that of the oxide-free argyrodite (cell 8). A decrease in conductivity is observed for the most oxygen-rich argyrodite (y>0.3) (cells 3 and 4). 5.4 P.S. 4.1 O 0.3 Cl 1.6 It should be noted that the ionic conductivity of the oxide-free argyrodite (cell 2) is virtually identical to that of the oxide-free argyrodite (cell 8).

[0158] FIG. 15 represents the ionic conductivity results measured as a function of temperature for cells 2 (triangles), 5 (squares), 6 (circles) and 7 (diamonds). FIG. 15 shows that the ionic conductivity values ​​of cells 5 and 6 containing argyrodites 5 and 6 (t=1.3 and y=0.3), respectively, obtained by two different syntheses (formulas (3) and (4) respectively), are substantially similar. For t=1.6 and y=0.3, FIG. 15 also shows that the ionic conductivity value of cell 7 containing argyrodite 7 is substantially lower compared to that of cell 2 containing argyrodite 2. As can be observed, thanks to the Li2SO4 precursor, the composition of the lithium oxysulfide argyrodite (e.g. lithium, oxygen and sulfur content) can be adjusted while remaining in substantially the same range of ionic conductivity. It can also be observed that a significant lithium deficiency induces a decrease in ionic conductivity.

[0159] FIG. 16 shows the ionic conductivity results measured as a function of temperature for cells 2 (squares), 3 (circles), 9 (triangles) and 10 (diamonds). FIG. 16 shows that for the same composition, the ionic conductivity of argyrodites obtained from Li2SO4 precursors (Argyrodites 2 and 3) is substantially higher than that of argyrodites obtained from Li2O precursors (Argyrodites 9 and 10). As shown in FIG. 8, the use of Li2SO4 type precursors allows better incorporation of oxygen into the argyrodite structure, which translates into improved conductivity as demonstrated by the results in FIG. 16.

[0160] Figure 17 shows the ionic conductivity results measured as a function of temperature for cells 2 (squares), 12 (circles), 13 (triangles), 14 (diamonds) and 15 (stars). Figure 17 shows that by adjusting the composition from the two halogens (i.e., chlorine and bromine), the ionic conductivity is not substantially modified and still maintains high conductivity. It should be noted that argyrodite 14 shows the best conductivity.

[0161] Figure 18 shows the ionic conductivity results measured as a function of temperature for cells 16 (squares), 17 (circles), 18 (triangles) and 19 (diamonds). Figure 18 shows that in the presence of Li2SO4, the incorporation of three halogens (i.e., chlorine, bromine and iodine) does not substantially modify the ionic conductivity and still maintains a high conductivity. It can be observed that an iodine content of 0.1 makes it possible to obtain better conductivity than higher contents.

[0162] Thus, by accumulating various analyses, it is possible to obtain argyrodite oxysulfides with the same ionic conductivity as the oxide-free one thanks to the Li2SO4 precursor, and improved compared to the use of the Li2O precursor. Furthermore, it is possible to adjust the composition of Li2SO4-based argyrodites with different halide contents and types while maintaining high ionic conductivity. Moreover, this adjustment allows to improve safety while keeping good conductive properties.

[0163] Figure 19 shows the ionic conductivity results measured as a function of temperature for cells 2 (squares), 20 (circles), 13 (triangles) and 21 (diamonds). Figure 19 shows that, independent of the composition of the Li2SO4-based argyrodite, increasing the amount of synthesis leads to a slight improvement in ionic conductivity. This demonstrates that the proposed solution can be easily applied on an industrial scale without loss of performance. Example 6 Electrochemical stability of inorganic compounds with argyrodite-type structure a) Preparation of pseudo-cells for electrochemical stability measurements

[0164] To determine the electrochemical stability of the argyrodites 2 and 9 prepared in Example 1, mock batteries were assembled according to the following procedure.

[0165] 5 wt. % of VGCF was mixed with 95 wt. % of Argyrodites 2 and 9 to obtain a composite positive pseudo electrode, thus observing oxidation-reduction reactions substantially representative of the final composite positive electrode composition that can be used in a battery configuration.

[0166] A solid electrolyte composed of the same argyrodite was then placed on the surface of the composite positive and false electrodes, and a negative electrode made of metallic lithium was then deposited on the surface of the solid electrolyte.

[0167] The assembly comprising the composite positive and false electrodes, the solid electrolyte and the metallic lithium negative electrode was then compressed and assembled into a sealed cell in a glove box under an inert atmosphere.

[0168] Sham batteries were assembled in the configuration shown in Table 3. [Table 3]

[0169] b) Cyclic voltammetry The electrochemical and oxidative stability of the pseudocells described in Example 6(a) was measured using a VMP-300 multichannel potentiostat (BioLogic).

[0170] Figure 20 shows the cyclic voltammetry results obtained for cell 22 and cell 23 (comparison cell) recorded at a scan rate of 0.05 mV / s in the potential range of Lithium Nickel Manganese Cobalt Oxide (NMC), i.e. between 2.5 V and 4.3 V vs. Li / Li+, at a temperature of about 30° C. Figure 20 shows the results obtained during the first four cycles for each of the two pseudo cells.

[0171] FIG. 20 shows that no reaction with lithium metal could be observed, demonstrating the chemical and electrochemical stability of argyrodite with lithium metal. In the potential range of NMC, a weak oxidation-reduction reaction could be observed in both pseudo cells, resulting in a lower current density (0.3 μA / cm2) and a lower polarization hysteresis in the case of cell 22 containing argyrodite obtained using Li2SO4 as precursor. It can also be observed that this reaction is reversible. Thus, argyrodite appears to be substantially electrochemically stable in the potential range of NMC, with the electrochemical stability being substantially improved in the case of argyrodite obtained using Li2SO4 as precursor. Thus, argyrodite obtained using Li2SO4 as precursor is substantially stable over the entire potential range of lithium metal batteries. Example 7 Electrochemical properties of inorganic compounds with argyrodite-type structure.

[0172] The electrochemical properties of Argyrodite 2 prepared in Example 1 were investigated. a) Preparation of composite positive electrode material 35% by weight of the Argyrodite 2 powder prepared in Example 1 was mixed with 65% by weight of LiNi 0.6 Mn 0.2 Co 0.2 O2 particles (NMC622) and 5 wt% of a mixture of Li400 carbon black (Denka™) and VGCF (75:25 mass ratio). The dry powders were mixed using a vortex mixer and then mixed with a mortar to homogenize the composite cathode material. b) Electrochemical cell configuration (Cell 24)

[0173] The electrochemical cell was assembled according to the following procedure.

[0174] A solid electrolyte was prepared by placing 80 mg of the Argyrodite 2 powder prepared in Example 1 in a 10 mm diameter mold under a pressure of 200 MPa. 13 mg of the composite cathode material prepared in Example 7(a) was then added onto the solid electrolyte in the mold, followed by an aluminum current collector. The contents of the mold including the solid electrolyte layer, composite cathode layer and aluminum current collector were then compressed under a pressure of 360 MPa for approximately 10 minutes. A 10 mm diameter metallic lithium electrode was then added on top of the stainless steel current collector facing the solid electrolyte layer, and the assembly was compressed under a pressure of 120 MPa for approximately 5 minutes.

[0175] The electrochemical cells were then assembled into a sealed cycling cell that was closed in a glove box under an inert atmosphere maintained at a pressure of 20 MPa. c) Electrochemical behavior of the electrochemical cell

[0176] The cell 24 assembled in Example 7(b) was Li / Li + The battery was cycled between 2.5 V and 4.3 V against the battery. The first five cycles were at C / 10, followed by four cycles at C / 4, then at 1.8 mAh / cm 2 Aging experiments were carried out at a temperature of 30° C. with constant charge and discharge currents of C / 2 for a surface capacity of 1.0 μm.

[0177] FIG. 21 shows a graph of charge capacity (circles) and discharge capacity (squares) and coulombic efficiency (triangles) as a function of cycle number over 100 cycles.

[0178] Figures 22 and 23 show the discharge profiles at different charge and discharge currents. More specifically, Figures 22 and 23 show graphs of discharge capacity and potential as a function of time (hours), respectively.

[0179] At C / 10, C / 4 and C / 2, the electrochemical cell produced approximately 170 mAh.g -1 , 160mAh.g -1 and 150mAh.g-1 It can be observed that the capacity of

[0180] Substantial capacity retention after 100 cycles can be observed, allowing for stable aging performance as demonstrated in Figure 22. Proper cyclability of the electrochemical cell at C / 2 for charge and discharge at a temperature of 30°C can be observed, demonstrating good electrochemical stability of Argyrodite 2 at potential and towards electronically conductive materials (i.e., mixture of Li400 carbon black and VGCF) and electrochemically active materials (i.e., NCM).

[0181] Several modifications can be made to any of the above embodiments without departing from the contemplated scope of the invention. All references, patent or scientific literature referred to in this application are incorporated herein by reference in their entirety for all purposes.

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