Lithium-ion conductive solid material

Abstract

Described are solid-state materials having ionic conductivity for lithium ions, methods for making said solid-state materials, methods for using said solid-state materials as solid electrolytes for electrochemical cells, solid-state structures selected from the group consisting of cathodes, anodes and separators for electrochemical cells comprising the solid-state materials, and electrochemical cells comprising such solid-state structures.

Description

[Technical field]

[0001] Described are solid-state materials having ionic conductivity for lithium ions, methods for making said solid-state materials, methods for using said solid-state materials as solid electrolytes for electrochemical cells, solid-state structures selected from the group consisting of cathodes, anodes and separators for electrochemical cells comprising the solid-state materials, and electrochemical cells comprising such solid-state structures. [Background technology]

[0002] The widespread use of solid-state lithium batteries has led to an increased demand for solid-state electrolytes with high conductivity for lithium ions. An important class of such solid electrolytes are the lithium argyrodites.

[0003] US2010 / 290969A1 discloses a compound of the general formula: Li + (12-n-x) B n+ X 2- 6-x Y - x The company discloses lithium argyrodite of During the ceremony, B is selected from the group P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb and Ta; X is selected from the group S, Se and Te; Y is selected from the group Cl, Br, I, F, CN, OCN, SCN, N3; And 0≦x≦2.

[0004] Only the following specific materials are disclosed: Li6PS5I, Li6PS5Br, Li6PS5Cl, Li7PS5Se.

[0005] US10,483,587B2 discloses a sulfide solid electrolyte containing lithium, phosphorus, sulfur, and two or more elements X selected from halogen elements. This sulfide solid electrolyte has an argyrodite-type crystal structure, and the molar ratio of sulfur to phosphorus "b(S / P)" and the molar ratio of element X to phosphorus "c(X / P)" satisfy the formula 0.23 < c / b < 0.57.

[0006] The following is also related art.

[0007] Oh Saneyuki et al., Chem. Mater. 2019, 31, 4936 - 4944 Zhou et al., J. Am. Chem. Soc. 2019, 141, 19002 - 19013

[0008] There is a continuous need for solid lithium ion conductors that exhibit ion conductivity suitable for use as solid electrolytes in solid lithium batteries.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0010]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] It is an object of the present disclosure to provide a solid-state material that can be used as a solid lithium-ion conducting electrolyte for an electrochemical cell, and further provides a method for producing said solid-state material, a method for using said solid-state material as a solid-state electrolyte for an electrochemical cell, a solid-state structure selected from the group consisting of a cathode, an anode and a separator for an electrochemical cell comprising said solid-state material, and an electrochemical cell comprising such a solid-state structure, wherein said solid-state structure comprises said solid-state material. [Means for solving the problem]

[0012] According to a first aspect, the parent composition Li6PY5X wherein X is one or more selected from F, Cl, Br, and I, and Y is one or more selected from O, S, Se, and Te; In the formula, 10 to 90 atomic % of P is Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ and is substituted with a cation selected from the group consisting of There are at least three and no more than six different cations of said groups. A solid material is provided having a composition derived from: [Brief description of the drawings]

[0013] [Figure 1] Figure 1a shows the single-phase XRD patterns of the three different materials, and Figure 1b shows the gradual shift in reflections. [Diagram 2] FIG. 2 shows a comparison of the XRD patterns of samples with and without step (c). [Diagram 3] FIG. 3 shows the XRD patterns of the two samples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Solid materials of parent composition Li6PY5X are known in the art, see for example the solid materials Li6PS5I, Li6PS5Cl and Li6PS5Br disclosed in US2010 / 290969A1. Typically, solid materials of parent composition Li6PY5X have an argyrodite structure. It is understood that solid materials having the parent composition Li6PY5X as defined above are not solid materials according to the present invention.

[0015] In the solid material according to the present invention having a composition derived from the parent composition, 10 to 90 atomic % of phosphorus is 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ In the solid material according to the invention, there are at least three and not more than six of said cations substituting phosphorus. As used herein, substitution of phosphorus by said cations means a fraction of lattice sites occupied by phosphorus in the parent material and by said cations in the material according to the invention. Thus, the phosphorus content of the solid material according to the invention is lower than in the parent composition, i.e. between 10 and 90 atomic % of the phosphorus content of the parent composition.

[0016] The cations substituting for phosphorus may have a different chemical valence (ionic charge) than phosphorus, so the lithium content may be lower or higher than in the parent composition to achieve electroneutrality.

[0017] Without wishing to be bound by any theory, it is currently believed that Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+It is hypothesized that the change in the parent composition by partial substitution of phosphorus with at least three and up to six different foreign cations selected from the group consisting of increases the configurational entropy (i.e., compositional disorder) within the argyrodite structure due to the introduction of foreign cations. More specifically, Zn, which substitutes 10 to 90 atomic % of the phosphorus in the parent composition, 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ It is assumed that the configurational entropy and / or vibrational entropy of the argyrodite material is increased due to the introduction of 3 to 6 different foreign cations selected from the group consisting of: This is assumed to increase the mobility of lithium ions and improve the ionic conductivity.

[0018] A preferred solid material according to the first aspect of the present invention has the general formula (I) Li 6+m P 1-x M1 (z1)+ (n1) M2 (z2)+ (n2) M3 (z3)+ (n3) M4 (z4)+ (n4) M5 (z5)+ (n5) M6 (z6)+ (n6) Y5X (I) (In the formula, X is one or more selected from F, Cl, Br and I, preferably one of F, Cl, Br and I; Y is one or more selected from O, S, Se and Te, preferably one of O, S, Se and Te; M1 (z1)+ ~M6 (z6)+ Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ is selected from the group consisting of Each of (n1) to (n3) is a number in the range of 0.05 to 0.3, (n4) is 0 or a number in the range of 0.05 to 0.3, (n5) is 0 or a number in the range of 0.05 to 0.3, (n6) is 0 or a number in the range of 0.05 to 0.3, (n1), (n2), (n3), (n4), (n5) and (n6) are selected independently of one another with the proviso that x=(n1)+(n2)+(n3)+(n4)+(n5)+(n6), where 0.1≦x≦0.9; And m=5-[5*(1-x)+(z1*n1)+(z2*n2)+(z3*n3)+(z4*n4)+(z5*n5)+(z6*n6)]] The composition is as follows:

[0019] In the solid material according to formula (I), three different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ or four different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ , or five different cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ , M5 (z5)+ , or six cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ , M5 (z5)+ , M6 (z6)+ replace a fraction of the phosphorus content of the parent composition Li6PY5X. Three, four, five or six different cations are Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ The variables (z1) to (z6) are selected from the group consisting of the associated cation M1 (z1)+ ~M6 (z6)+That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge, and (z4) is M4 (z4)+ is the ionic charge, and (z5) is M5 (z5)+ is the ionic charge, and (z6) is M6 (z6)+ is the ionic charge.

[0020] The variables (n1) to (n6) represent the associated cations M1 present in formula (I). (z1)+ ~M6 (z6)+ Each of (n1) to (n3) is an independently selected number ranging from 0.05 to 0.3. Three different cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ If only n is present, then (n4) = (n5) = (n6) = 0. (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ When present, (n1)-(n4) are independently selected numbers ranging from 0.05 to 0.3, and (n5)=(n6)=0. Five distinct cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ , M5 (z5)+ When present, (n1)-(n5) are independently selected numbers ranging from 0.05 to 0.3, and (n6)=0. Six distinct cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ , M5 (z5)+ and M6 (z6)+ If present, (n1) through (n6) are independently selected numbers ranging from 0.05 to 0.3. In each case, (n1) through (n6) satisfy the following conditions: the variable x, which is the sum of (n1) through (n6), ranges from 0.1 to 0.9, and different cations M1 (z1)+ ~M6 (z6)+This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by

[0021] The variable m is the cation M1 (z1) +~M6 (z6)+ FIG. 1 shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance the deviation of the ionic charge of m from the chemical valence of phosphorus (+5). The variable m is positive when the contribution of cations with an ionic charge less than 5+ is greater than the contribution of cations with an ionic charge of 5+ or greater. The variable m is negative when the contribution of cations with an ionic charge greater than 5+ to m is greater than the contribution of cations with an ionic charge of 5+ or less. The variable m is 0 when the contribution of cations with an ionic charge less than 5+ to m balances the contribution of cations with an ionic charge greater than 5+ to m.

[0022] In the solid material according to formula (I), X is one or more selected from F, Cl, Br and I, and Y is one or more selected from O, S, Se and Te. Preferably, X is one of F, Cl, Br and I, and Y is one of O, S, Se and Te. More preferably, X is one of F, Cl, Br and I, and Y is S.

[0023] A more preferred solid material according to the first aspect of the present invention has the general formula (II) Li 6+m P 1-x M1 (z1)+ (n1) M2 (z2)+ (n2) M3 (z3)+ (n3) M4 (z4)+ (n4) Y5X (II) (In the formula, X is one or more selected from F, Cl, Br and I, preferably one of F, Cl, Br and I; Y is one or more selected from O, S, Se and Te, preferably one of O, S, Se and Te; M1(z1)+ ~M4 (z4)+ Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ is selected from the group consisting of Each of (n1) to (n3) is a number in the range of 0.05 to 0.3, (n4) is 0 or a number in the range of 0.05 to 0.3, (n1), (n2), (n3) and (n4) are independently selected with the proviso that x=(n1)+(n2)+(n3)+(n4), where 0.1≦x≦0.9; And m=5-[5*(1-x)+(z1*n1)+(z2*n2)+(z3*n3)+(z4*n4)]] The composition is as follows:

[0024] In the solid material according to formula (II), three different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ or four different cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ replaces a fraction of the phosphorus content of the parent composition Li6PY5X. Three or four cations are Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ The variables (z1) to (z4) are selected from the group consisting of the associated cation M1 (z1)+ ~M4 (z4)+ That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge, and (z4) is M4 (z4)+ is the ionic charge.

[0025] The variables (n1) to (n4) represent the associated cations M1 present in formula (II). (z1)+ ~M4 (z4)+ Each of (n1) to (n3) is an independently selected number ranging from 0.05 to 0.3. The four cations M1 (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ When present, (n4) is another independently selected number ranging from 0.05 to 0.3. (z1)+ , M2 (z2)+ , M3 (z3)+ If only three cations, M1 and M2, are present, then (n4) = 0. In each case, (n1)-(n4) satisfy the following conditions: the variable x, which is the sum of (n1)-(n4), is in the range 0.1-0.9, and there are three different cations, M1 and M2. (z1)+ ~M4 (z4)+ Or M1 (z1)+ ~M3 (z3)+ (The fourth cation M4 (z4)+ This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by Li6PY5X (in the absence of

[0026] The variable m is the cation M1 (z1)+ ~M4 (z4)+ Or M1 (z1)+ ~M3 (z3)+ (The fourth cation M4 (z4)+ FIG. 1 shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance deviations in the ionic charge of the cations (in the absence of ) from the chemical valence of phosphorus (+5). The variable m is positive when the contribution of cations with an ionic charge less than 5+ is greater than the contribution of cations with an ionic charge of 5+ or greater. The variable m is negative when the contribution of cations with an ionic charge greater than 5+ to m is greater than the contribution of cations with an ionic charge of 5+ or less. The variable m is 0 when the contribution of cations with an ionic charge less than 5+ to m balances the contribution of cations with an ionic charge greater than 5+ to m.

[0027] In the solid material according to formula (II), X is one or more selected from F, Cl, Br and I, and Y is one or more selected from O, S, Se and Te. Preferably, X is one of F, Cl, Br and I, and Y is one of O, S, Se and Te. More preferably, X is one of F, Cl, Br and I, and Y is S.

[0028] In a first group of particularly preferred solid materials according to the invention, three different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ are present, which replace a fraction of the phosphorus content of the parent composition Li6PY5X.

[0029] Certain preferred solid materials of the first group are of formula (IIa) Li 6+m P 1-x M1 (z1)+ (n1) M2 (z2)+ (n2) M3 (z3)+ (n3) Y5X (IIa) (In the formula, X is selected from F, Cl, Br and I, preferably I; Y is selected from O, S, Se and Te, preferably S; M1 (z1)+ ~M3 (z3)+ is Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ is selected from the group consisting of Each of (n1) to (n3) is a number in the range of 0.05 to 0.3, and (n1), (n2) and (n3) are selected independently of one another under the condition that x=(n1)+(n2)+(n3) (0.1≦x≦0.9); And m=5-[5*(1-x)+(z1*n1)+(z2*n2)+(z3*n3)]. The composition is as follows:

[0030] In the solid material according to formula (IIa), three different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ replace a fraction of the phosphorus content of the parent composition Li6PY5X. The three different cations are Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ The variables (z1) to (z3) are selected from the group consisting of the associated cation M1 (z1)+ ~M3 (z3)+ That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge.

[0031] The variables (n1) to (n3) represent the relevant cations M1 present in formula (IIa). (z1)+ ~M3 (z3)+ Each of (n1) to (n3) is an independently selected number ranging from 0.05 to 0.3, and satisfies the following conditions: the variable x, which is the sum of (n1) to (n3), is in the range of 0.1 to 0.9, and the different cations M1 (z1)+ ~M3 (z3)+ This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by

[0032] The variable m is the cation M1 (z1) +~M3 (z3)+ This shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance the deviations of the ionic charge from the chemical valence of phosphorus (+5). Since there are no cations with a charge beyond 5+, the variable m is positive.

[0033] In the solid material according to formula (IIa), X is one selected from F, Cl, Br and I, and Y is one selected from O, S, Se and Te. Preferably, X is I (iodine). Preferably, Y is S (sulfur).

[0034] More preferably, X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IIa'): Li 6+m P 1-x M1 (z1)+ (n1) M2 (z2)+ (n2) M3 (z3)+ (n3) S5I (IIa') (wherein x, n1, n2, n3, z1, z2, z3 and m are as defined above for formula (IIa). The composition is as follows:

[0035] Most preferably, M1 (z1)+ is Si 4+ And M2 (z2)+ Ge 4+ And M3 (z3)+ is Sb 5+ and X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IIa″): Li 6+m P 1-x S (n1) Ge (n2) Sb (n3) S5I (IIa'') (wherein x, n1, n2, n3 and m are as defined above for formula (IIa). The composition is as follows:

[0036] In the more preferred materials of the above-defined first group of preferred solid-state materials according to the invention, three different cations M1, which substitute a fraction of the phosphorus content of the parent composition Li6PY5X, (z1)+ , M2 (z2)+ , M3 (z3)+ are present in equal fractions n. Such more preferred solid materials of the first group are represented by the formula (IIc): Li 6+m P 1-3n M1 (z1)+ n M2 (z2)+ n M3 (z3)+ nY5X (IIc) (In the formula, X is selected from F, Cl, Br and I, preferably I; Y is selected from O, S, Se and Te, preferably S; M1 (z1)+ ~M3 (z3) + is Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ is selected from the group consisting of n is a number in the range of 0.05 to 0.3, preferably 0.2 to 0.28, provided that x=3n (0.1≦x≦0.9); And m=5-[5*(1-3n)+n*(z1+z2+z3)]. The composition is as follows:

[0037] In the solid material according to formula (IIc), three different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ replace a fraction of the phosphorus content of the parent composition Li6PY5X. The three cations are Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ The variables (z1) to (z3) are selected from the group consisting of the associated cation M1 (z1)+ ~M3 (z3)+ That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge.

[0038] Cation M1 (z1)+ ~M3 (z3)+ Each of the three different cations M1 is present in the same fraction, represented by the variable n, which is a number ranging from 0.05 to 0.3, preferably from 0.2 to 0.28, and satisfies the following conditions: (z1)+ ~M3 (z3)+ The variable x, i.e. x = 3n, is in the range of 0.1 to 0.9 and is the sum of the fractions of different cations M1(z1)+ ~M3 (z3)+ This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by

[0039] The variable m is the cation M1 (z1)+ ~M3 (z3)+ This shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance the deviations of the ionic charge from the chemical valence of phosphorus (+5). Since there are no cations with a charge beyond 5+, the variable m is positive.

[0040] In the solid material according to formula (IIc), X is one selected from F, Cl, Br and I, and Y is one selected from O, S, Se and Te. Preferably, X is I (iodine). Preferably, Y is S (sulfur).

[0041] Most preferably, X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IIc'): Li 6+m P 1-3n M1 (z1)+ n M2 (z2)+ n M3 (z3)+ n S5I (IIc') (wherein n, z1, z2, z3 and m are as defined above for formula (IIc). The composition is as follows:

[0042] Most preferably, M1 (z1)+ is Si 4+ And M2 (z2)+ Ge 4+ And M3 (z3)+ is Sb 5+ and X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IIc″): Li 6+m P 1-3n S n Ge n Sbn S5I (IIc'') wherein n and m are as defined above for formula (IIc). The composition is as follows:

[0043] Preferred solid materials of the first group defined above are Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 S5I, Li 6.342 P 0.5 S 0.166 Ge 0.166 Sb 0.166 S5I and Li 6.171 P 0.75 S 0.083 Ge 0.083 Sb 0.083 It is S5I.

[0044] In a second group of particularly preferred solid materials according to the invention, four different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ are present, which replace a fraction of the phosphorus content of the parent composition Li6PY5X.

[0045] Certain preferred solid materials of the second group are represented by formula (IIb) Li 6+m P 1-x M1 (z1)+ (n1) M2 (z2)+ (n2) M3 (z3)+ (n3) M4 (z4)+ (n4) Y5X (IIb) (In the formula, X is selected from F, Cl, Br and I, preferably I; Y is selected from O, S, Se and Te, preferably S; M1 (z1)+ ~M4 (z4)+ is Si 4+ , Ge 4+ , Sn 4+ and Sb5+ and Each of (n1) to (n4) is a number in the range of 0.05 to 0.3, and (n1), (n2), (n3) and (n4) are selected independently of one another under the condition that x=(n1)+(n2)+(n3)+(n4) (0.1≦x≦0.9); And m=5-[(5*(1-x)+(z1*n1)+(z2*n2)+(z3*n3)+(z4*n4)]). The composition is as follows:

[0046] In the solid material according to formula (IIb), four different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ replace a fraction of the phosphorus content of the parent composition Li6PY5X. The four cations are Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ The variables (z1) to (z4) represent the associated cations M1 (z1)+ ~M4 (z4)+ That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge, and (z4) is M4 (z4)+ is the ionic charge.

[0047] The variables (n1) to (n4) represent the relevant cations M1 present in formula (IIb). (z1)+ ~M4 (z4)+ Each of (n1) to (n4) is an independently selected number ranging from 0.05 to 0.3, and satisfies the following conditions: the variable x, which is the sum of (n1) to (n4), is in the range of 0.1 to 0.9, and the different cations M1 (z1)+ ~M4 (z4)+ This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by

[0048] The variable m is the cation M1 (z1)+ ~M4 (z4)+This shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance the deviations of the ionic charge from the chemical valence of phosphorus (+5). Since there are no cations with a charge beyond 5+, the variable m is positive.

[0049] In the solid material according to formula (IIb), X is one selected from F, Cl, Br and I, and Y is one selected from O, S, Se and Te. Preferably, X is I (iodine). Preferably, Y is S (sulfur).

[0050] Most preferably, X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IIb'): Li 6+m P 1-x S (n1) Ge (n2) Sn (n3) Sb (n4) S5I (IIb') (wherein x, n1, n2, n3, n4 and m are as defined above for formula (IIb). The composition is as follows:

[0051] In the more preferred materials of the above-defined second group of preferred solid-state materials according to the invention, four different cations M1, which substitute a fraction of the phosphorus content of the parent composition Li6PY5X, (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ are present in equal fractions n. Such more preferred solid materials of the first group are represented by the formula (IId): Li 6+m P 1-4n M1 (z1)+ n M2 (z2)+ n M3 (z3)+ n M4 (z4)+ n Y5X (IId) (In the formula, X is selected from F, Cl, Br and I, preferably I; Y is selected from O, S, Se and Te, preferably S; M1 (z1)+ ~M4 (z4)+ is Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ and n is a number in the range of 0.05 to 0.22, preferably 0.15 to 0.21, provided that x=4n (0.1≦x≦0.9); And m=5-[(5*(1-4n)+n*(z1+z2+z3+z4)]). The composition is as follows:

[0052] In the solid material according to formula (IId), four different cations M (z1)+ , M2 (z2)+ , M3 (z3)+ , M4 (z4)+ replace a fraction of the phosphorus content of the parent composition Li6PY5X. The four cations are Si 4+ , Ge 4+ , Sn 4+ and Sb 5+ The variables (z1) to (z4) represent the associated cations M1 (z1)+ ~M4 (z4)+ That is, (z1) represents the ionic charge (chemical valence) of the cation M1 (z1)+ is the ionic charge, and (z2) is M2 (z2)+ is the ionic charge, and (z3) is M3 (z3)+ is the ionic charge, and (z4) is M4 (z4)+ is the ionic charge.

[0053] Cation M1 (z1)+ ~M4 (z4)+ Each of the four different cations M1 is present in the same fraction, represented by the variable n, which is a number ranging from 0.05 to 0.22, preferably from 0.15 to 0.21, and satisfies the following conditions: (z1)+ ~M4 (z4)+ The variable x, i.e., x=4n, ranges from 0.1 to 0.9 and is the sum of the fractions of different cations M1(z1)+ ~M4 (z4)+ This corresponds to a substitution of 10 to 90 atomic % of phosphorus in the parent composition Li6PY5X by

[0054] The variable m is the cation M1 (z1) +~M4 (z4)+ This shows how the lithium ion content changes compared to the parent composition Li6PY5X to balance the deviations of the ionic charge from the chemical valence of phosphorus (+5). Since there are no cations with a charge beyond 5+, the variable m is positive.

[0055] In the solid material according to formula (IId), X is one selected from F, Cl, Br and I, and Y is one selected from O, S, Se and Te. Preferably, X is I (iodine). Preferably, Y is S (sulfur).

[0056] Most preferably, X is I (iodine) and Y is S (sulfur). In such a preferred case, the solid material has the formula (IId'): Li 6+m P 1-4n S n Ge n Sn n Sb n Y5X (IId') wherein n and m are as defined above for formula (IId). The composition is as follows:

[0057] The solid material according to the first aspect defined above may be crystalline as detectable by X-ray diffraction (XRD) techniques. A solid material is said to be crystalline if it exhibits the long range order characteristic of crystals, as shown by the presence of well-defined reflections in its XRD pattern. In this context, a reflection is considered to be well-defined if its intensity is more than 10% above background.

[0058] The solid material according to the first aspect defined above may consist of a single phase or of more than one phase, for example a major phase (primary phase) and minor amounts of impurities and secondary phases. It is understood that formula (I) is an empirical formula (total formula) that can be determined by elemental analysis. Thus, formula (I) defines the composition averaged over all phases present in the solid material. However, the solid material according to the first aspect defined above comprises at least one phase, which itself has a composition according to formula (I). When the crystalline solid material according to the first aspect defined above contains more than one phase, the mass fraction of the phases that do not themselves have a composition according to formula (I) (e.g. impurity phases, secondary phases) is so small that the composition averaged over all phases is according to formula (I). The total mass fraction of the secondary and impurity phases may be 20% or less, preferably 10% or less, more preferably 5% or less, most preferably 3% or less, based on the total mass of the solid material. The secondary and impurity phases, if present, consist mainly of the precursors used to prepare the solid materials, e.g. LiX (X as defined above) and Li2Y (Y as defined above), and sometimes impurity phases that may originate from impurities of the precursors or products formed by side reactions of the precursors (e.g. Li3PS4). For details of the preparation of the solid materials according to the first aspect defined above, reference is made to the information presented below in the context of the second aspect of the present disclosure.

[0059] In certain cases, the solid material according to the first aspect defined above is in the form of a polycrystalline powder or in the form of a single crystal.

[0060] The crystalline solid material according to the first aspect defined above has an argyrodite structure characterized by the cubic space group F-43m. The argyrodite structure is generally determined by powder XRD measurements as known in the art. Details are given in the Examples section.

[0061] The solid-state materials according to the first aspect defined above have in each case an ionic conductivity of at least 0.1 mS / cm, preferably at least 1 mS / cm and more preferably at least 10 mS / cm at a temperature of 25° C. The ionic conductivity is determined in the usual manner known in the field of developed battery materials by electrochemical impedance spectroscopy (for details see the Examples section below).

[0062] Preferred solid materials according to the first aspect, as defined above, are those which have one or more of the particular preferred features disclosed above.

[0063] According to a second aspect, there is provided a method for obtaining a solid material according to the first aspect defined above, said method comprising the following steps: (a) Precursor of: (1) One or more of oxide, sulfide, selenide, and telluride of lithium; (2) One or more of phosphorus oxides, sulfides, selenides, and tellurides; (3) one or more compounds LiX, where X is selected from F, Cl, Br, and I; (4) Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ a compound selected from the group consisting of metal oxides, sulfides, selenides and tellurides of at least three and not more than six cations selected from the group consisting of (5) Optionally, one or more of the elemental forms of S, Se, and Te. providing a reaction mixture comprising: In the reaction mixture, the molar ratio of every element is Li6PY5X wherein X is one or more selected from Cl, Br, and I, and Y is one or more selected from O, S, Se, and Te; In the formula, 10 to 90 atomic % of P is Zn 2+ , Ga3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ substituted with a cation from the group consisting of selected to correspond to a composition derived from (b) Reacting the precursor to produce the parent compound Li6PY5X wherein X is one or more selected from F, Cl, Br, and I, and Y is one or more selected from O, S, Se, and Te; In the formula, 10 to 90 atomic % of P is Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ and is substituted with a cation from the group consisting of and obtaining a solid material having a composition derived from said groups, wherein at least three and not more than six different cations of said groups are present. Includes.

[0064] In step a) of the method according to the second aspect defined above, a reaction mixture is provided comprising a precursor for the reaction product formed in step b), said precursor being (1) One or more of oxide, sulfide, selenide, and telluride of lithium; (2) One or more of phosphorus oxides, sulfides, selenides, and tellurides; (3) one or more compounds LiX, where X is selected from F, Cl, Br, and I; (4) Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ a compound selected from the group consisting of metal oxides, sulfides, selenides and tellurides of at least three and not more than six cations selected from the group consisting of (5) Optionally, one or more of the elemental forms of S, Se, and Te. It is.

[0065] Preferably, the reaction mixture provided in step (a) consists of precursors (1) to (4) or precursors (1) to (5) as defined above.

[0066] Preferably, in said reaction mixture provided in step (a), the molar ratio of elements corresponds to one of general formula (I) as defined above, preferably general formula (II) as defined above, most preferably general formula (IIa), (IIa'), IIa''), (IIb), (IIb'), (IIc), (IIc'), (IIc''), (IId) and (IId') as defined above.

[0067] To prepare a solid material having a composition according to formula (I), the precursor (4) is Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ The compound may comprise or consist of a compound selected from the group consisting of metal oxides, sulfides, selenides or tellurides of at least three and not more than six metal cations selected from the group consisting of:

[0068] To prepare a solid material having a composition according to formula (II), the precursor (4) is Zn 2+ , Ga 3+ , Si 4+ , Ge 4+ , Sn 4+ , Sb 5+ and W 6+ The compound may comprise or consist of a compound selected from the group consisting of metal oxides, sulfides, selenides or tellurides of three or four metal cations selected from the group consisting of:

[0069] In certain preferred methods, the precursor (1) is Li2S, and / or the precursor (2) is P2S5, and / or the precursor (3) is LiI, and / or The precursor (4) is selected from the group consisting of SiS2, GeS2, SnS2, and Sb2S3; and / or said precursor (5) is elemental sulfur or is absent.

[0070] To prepare a solid material having a composition according to formula (IIa) or (IIc), the precursor (4) is Si 4+ , Ge 4+ , Sn 4+ , and Sb 5+ The compound may comprise or consist of a compound selected from the group consisting of metal oxides, sulfides, selenides, or tellurides of three cations selected from the group consisting of:

[0071] To prepare a solid material having a composition according to formula (IIa') or (IIc'), The precursor (1) comprises or consists of Li2S, Precursor (2) comprises or consists of P2S5, Precursor (3) comprises or consists of LiI, The precursor (4) comprises or consists of three compounds selected from the group consisting of SiS2, GeS2, SnS2 and Sb2S3; Precursor (5) may comprise, consist of, or be free of elemental sulfur.

[0072] To prepare a solid material having a composition according to formula (IIa″) or (IIc″), The precursor (1) comprises or consists of Li2S, Precursor (2) comprises or consists of P2S5, Precursor (3) comprises or consists of LiI, Precursor (4) comprises or consists of SiS2, GeS2 and Sb2S3; Precursor (5) may comprise, consist of, or be free of elemental sulfur.

[0073] To prepare a solid material having a composition according to formula (IIb) or (IId), the precursor (4) is Si 4+ , Ge 4+ , Sn 4+ , and Sb 5+ The present invention comprises or consists of a compound selected from the group consisting of all oxides, sulfides, selenides, or tellurides of the above-mentioned compounds.

[0074] To prepare a solid material having a composition according to formula (IIb') or (IId'), The precursor (1) comprises or consists of Li2S, Precursor (2) comprises or consists of P2S5, Precursor (3) comprises or consists of LiI, Precursor (4) comprises or consists of SiS2, GeS2, SnS2 and Sb2S3, and Precursor (5) may comprise, consist of, or be free of elemental sulfur.

[0075] In step (a) of the process defined above, the reaction mixture is obtained by mixing the precursors. The mixing of the precursors may be carried out by grinding the precursors together. The grinding may be carried out using any suitable means.

[0076] In step (a), it is useful to carry out any treatment under a protective gas atmosphere.

[0077] In step (b) of the method defined above, the precursors are reacted to obtain a solid material as defined above. In other words, in step (b), the precursors in the reaction mixture are reacted with each other to obtain a solid material having a composition according to general formula (I). The reaction of the precursors may be achieved, for example, by a thermochemical or mechanochemical process.

[0078] In a first preferred alternative of the method according to the invention, the reaction of the precursor in step b) is achieved by thermochemical treatment. Such a method comprises the following steps: (a) preparing or providing a solid reaction mixture comprising a precursor as defined above; (b1) heat treating the reaction mixture at a temperature range of 200° C. to 600° C. for a total of 1 to 48 hours or more to form a reaction product, and cooling the reaction product to obtain a solid material having a composition according to general formula (I); Includes.

[0079] The reaction mixture provided in step (a) may be formed into pellets, which are heat treated in step (b1), resulting in a solid material in the form of pellets or chunks, which may be ground into powder for further processing.

[0080] The reaction mixture prepared in process step (a) is heat treated in step (b1) to allow the precursors to react, said reaction being considered to be a substantially solid state reaction, i.e. the reaction mixture takes place in the solid state.

[0081] The heat treatment may be carried out in a closed vessel, which may be a sealed quartz tube or any other type of container that can withstand the temperatures of the heat treatment and does not undergo reaction with any of the precursors, such as a vitreous carbon crucible or a tantalum crucible.

[0082] In step (b1), the reaction mixture may be heat treated at a temperature range of 200° C. to 600° C. for a total of 1 hour to 48 hours to form a reaction product. More specifically, in step (b1), the reaction mixture may be heat treated at a temperature range of 350° C. to 550° C. for a total of 5 hours to 30 hours. The heat treatment in step (b1) may be carried out under vacuum or under a protective gas atmosphere.

[0083] Once the period of heat treatment in step (b1) is completed, the formed reaction product is allowed to cool. In this way, a solid material having a composition according to general formula (I) is obtained. Cooling of the reaction product may be performed using a cooling rate of 1-10°C per minute. Alternatively, cooling is achieved by stopping the heating after the period of heat treatment is completed (so-called natural cooling).

[0084] In a second preferred alternative of the method according to the invention, the reaction of the precursor in step (b) is achieved by mechanochemical treatment. Such a method comprises the following steps: (a) preparing or providing a solid reaction mixture comprising a precursor as defined above; (b2) mechanochemically treating the solid reaction mixture to obtain a solid material having a composition according to general formula (I) Includes.

[0085] In step (b2), the mechanochemical treatment can be accomplished by mechanochemical grinding, e.g., ball milling. Apparatus for mechanochemical treatment, e.g., ball mills, and their use are generally known in the art. The mechanochemical treatment is preferably carried out at a rotation speed of 100 rpm to 500 rpm for a period of 15 to 30 hours. In certain cases, the mechanochemical treatment is carried out at a speed in the range of 100 rpm to 300 rpm for 0.5 hours to 3 hours, and then at a speed of 400 rpm to 500 rpm for another 12 to 29 hours.

[0086] The reaction product obtained by ball milling is typically in the form of a powder.

[0087] The method according to the second preferred alternative defined above comprises the following steps: (c) annealing the solid material obtained by the mechanochemical treatment at a temperature range of 200° C. to 600° C. for a total period of 1 to 48 hours, and then cooling the annealed solid material. It may further include.

[0088] Annealing of the reaction product obtained by mechanochemical treatment in step (b1) results in an increase in crystallinity, as indicated by the presence of more clearly defined reflections in the X-ray diffraction pattern, compared to a solid material having the same composition and prepared in the same manner (i.e., the same steps (a) and (b2)) but without step (c).

[0089] Preferably, the powder obtained in step (b2) is pressed into pellets which are annealed in step (c2).

[0090] The annealing may be carried out in a closed vessel, which may be a sealed quartz tube or any other type of container that can withstand the annealing temperatures and does not undergo reaction with any of the precursors, such as a vitreous carbon crucible or a tantalum crucible.

[0091] In step (c), the reaction mixture may be annealed for a total time of 1 hour to 48 hours at a temperature range of 200° C. to 600° C. More specifically, in step (c), the reaction mixture may be annealed for a total time of 5 hours to 30 hours at a temperature range of 350° C. to 550° C. The heat treatment in step (c) may be carried out under vacuum or under a protective gas atmosphere.

[0092] Once the period of heat treatment in step (c) is completed, the formed reaction product is allowed to cool. In this way, a solid material having a composition according to general formula (I) is obtained. Cooling of the reaction product may be carried out using a cooling rate of 1-10° C. per minute or by quenching, for example, in liquid nitrogen. Alternatively, cooling is achieved by stopping the heating after the period of heat treatment is completed (so-called natural cooling).

[0093] Preferred methods according to the second aspect defined herein are those having one or more of the particular features disclosed above.

[0094] The solid material obtained by the method according to the first aspect defined above or according to the second aspect defined above can be used as a solid electrolyte for an electrochemical cell. In the present specification, the solid electrolyte can form a component of a solid structure for an electrochemical cell, said solid structure being selected from the group consisting of a cathode, an anode and a separator. Thus, the solid material obtained by the method according to the first aspect defined above or according to the second aspect defined above can be used (optionally in combination with additional components) to manufacture a solid structure for an electrochemical cell, such as a cathode, an anode or a separator.

[0095] The present disclosure thus further provides the use of a solid material obtained by the method according to the first aspect as defined above or by the method according to the second aspect as defined above as a solid electrolyte for an electrochemical cell. Herein, a solid material obtained by the method according to the first aspect as defined above or by the method according to the second aspect as defined above may have a composition according to general formula (I) as defined above, preferably according to general formula (II) as defined above, most preferably according to general formulas (IIa), (IIa'), (IIa''), (IIb), (IIb'), (IIc), (IIc'), (IIc''), (IId) and (IId') as defined above. With regard to the particular and preferred solid materials obtained by the method according to the first aspect as defined above or by the method according to the second aspect as defined above, the same applies as disclosed above in the context of the first aspect.

[0096] More particularly, the present disclosure further provides a method of use of the solid material obtained by the method according to the first aspect defined above or according to the second aspect defined above as a component of a solid structure for an electrochemical cell, said solid structure being selected from the group consisting of a cathode, an anode and a separator.

[0097] In the context of the present disclosure, an electrode that develops a net negative charge during discharge is called an anode, and an electrode that develops a net positive charge during discharge is called a cathode. Suitable electrochemically active cathode materials and suitable electrochemically active anode materials are known in the art. A cathode of a solid electrochemical cell usually comprises, besides an active cathode material, a solid electrolyte as a further component. Similarly, an anode of a solid electrochemical cell usually comprises, besides an active anode material, a solid electrolyte as a further component. The solid electrolyte may be a solid material obtained by the method according to the first aspect defined above or according to the second aspect defined above.

[0098] In an electrochemical cell, the separator electrically separates the cathode and the anode from each other. In a solid-state electrochemical cell, the separator comprises a solid electrolyte. Said solid electrolyte may be a solid material obtained by the method according to the first aspect defined above or according to the second aspect defined above.

[0099] The present disclosure further provides a solid structure for an electrochemical cell, the solid structure being selected from the group consisting of a cathode, an anode and a separator, the solid structure for an electrochemical cell comprising a solid material obtained by the method according to the first aspect as defined above or by the method according to the second aspect as defined above. As used herein, the solid material according to the first aspect as defined above or obtained by the method according to the second aspect as defined above may have a composition according to general formula (I) as defined above, preferably according to general formula (II) as defined above, most preferably according to one of general formulas (IIa), (IIa'), (IIa''), (IIb), (IIb'), (IIc), (IIc'), (IIc''), (IId) and (IId') as defined above.

[0100] The morphology of the solid-state structures for electrochemical cells, and in particular for solid-state lithium batteries, depends inter alia on the morphology of the electrochemical cell itself.

[0101] The present disclosure further provides a solid structure for an electrochemical cell, the solid structure being selected from the group consisting of a cathode, an anode and a separator, the solid structure for an electrochemical cell comprising a solid material according to the first aspect as defined above or obtained by the method according to the second aspect as defined above.

[0102] The present disclosure further provides an electrochemical cell comprising a solid-state material obtained by the method according to the first aspect defined above or by the method according to the second aspect defined above, in which the solid-state material obtained by the method according to the first aspect defined above or by the method according to the second aspect defined above can form one or more solid structure components selected from the group consisting of a cathode, an anode and a separator.

[0103] The electrochemical cell defined above comprises the following components: α) at ​​least one anode; β) at least one cathode; γ) at least one separator

[0023] The rechargeable electrochemical cell may comprise: At least one of the three components is a solid structure selected from the group consisting of the cathode, the anode and the separator and comprises a solid material according to the first aspect defined above or obtained by the method according to the second aspect defined above.

[0104] Suitable electrochemically active cathode materials and suitable electrochemically active anode materials are known in the art. In the above electrochemical cells, the anode α) may comprise graphitic carbon, metallic lithium, or a metal alloy containing lithium as the anode active material.

[0105] The electrochemical cell may be an alkali metal-containing cell, in particular a lithium-ion-containing cell. In a lithium-ion-containing cell, charge transport is via the Li + This is done by ions.

[0106] The electrochemical cell may have a disk-like or prismatic shape.The electrochemical cell may include a housing, which may be made of steel or aluminum.

[0107] The electrochemical cells may be combined into a solid-state battery having both solid electrodes and solid electrolytes. A further aspect of the present disclosure refers to a battery, more particularly an alkali metal ion battery, in particular a lithium ion battery comprising at least one electrochemical cell as described above, such as two or more electrochemical cells as described above. The electrochemical cells may be combined with each other in an alkali metal ion battery, for example in series or in parallel. Series is preferred.

[0108] The electrochemical cells or batteries described herein can be used to make or operate stationary applications such as cars, computers, personal digital assistants, cell phones, watches, video cameras, digital cameras, thermometers, calculators, laptop BIOS, communication devices or remote car keys, and energy storage devices for power plants. A further aspect of the present disclosure is a method of making or operating stationary applications such as cars, computers, personal digital assistants, cell phones, watches, video cameras, digital cameras, thermometers, calculators, laptop BIOS, communication devices, remote car keys, and energy storage devices for power plants by using at least one inventive battery or at least one inventive electrochemical cell.

[0109] A further aspect of the present disclosure is the use of the electrochemical cell described above in an automotive vehicle, a bicycle powered by an electric motor, a robot, an aircraft (e.g., an unmanned aerial vehicle including a drone), a ship, or a stationary energy storage station.

[0110] The present disclosure further provides a device comprising at least one electrochemical cell of the present invention as described above.Preferred is a mobile device, such as a vehicle, such as a car, a bicycle, an aircraft, or a water vehicle, such as a boat or a ship.Other examples of mobile devices are portable, such as a computer, especially a laptop, a phone, or a power tool, such as from the construction sector, especially a drill, a battery-powered screwdriver, or a battery-powered tacker.

[0111] The present invention is further illustrated by the following non-limiting examples. EXAMPLES

[0112] 1. Material preparation All steps were carried out under an argon atmosphere.

[0113] In step (a), four different reaction mixtures (total amount of about 1.5 g) consisting of the precursors Li2S (99.99%, Sigma Aldrich), P2S5 (99%, Sigma Aldrich), GeS2 (99.9%, GoodFellow), SiS2 (99.99%, GoodFellow), Sb2S3 (99.99%, Alfa Aesar), S8 (99.99%, Sigma Aldrich), and LiI (99.999%, Sigma Aldrich) were placed in a 70 mL zirconia grinding jar containing ten zirconia grinding balls (diameter 10 mm). The stoichiometric ratio of the precursors was Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 S5I, Li 6.342 P 0.5 S 0.166 Ge 0.166 Sb 0.166 S5I and Li 6.171 P 0.75 S 0.083 Ge 0.083 Sb 0.083 Selected to match the composition selected from S5I.

[0114] For comparison, a reaction mixture was provided consisting of the above precursors, except for P2S5, where the stoichiometric ratio of the precursors was Li 6.7 S 0.33 Ge 0.33 Sb 0.33 Selected to match S5I.

[0115] The reaction of the precursor was achieved by mechanochemical treatment. Thus, in step (b), the reaction mixture was milled at 250 rpm for 1 h, then the rotation speed was increased to 450 rpm and milling was continued for another 20 h.

[0116] The collected powder was pressed into pellets (approximately 300 mg, 10 mm in diameter) at 3 tonnes and vacuum sealed in a quartz ampoule (10 -3 The ampoule was subjected to dynamic vacuum (10 -3 The film was pre-dried at 500 °C for 10 min using a heat gun under 100 mbar to avoid traces of moisture.

[0117] The sample was then annealed at 400° C. for 24 h (step (c), heating and cooling rate was 5° C. / min). The cooling rate corresponded to natural cooling.

[0118] Composition Li 6.7 S 0.33 Ge 0.33 Sb 0.33 Samples with S5I (not according to the invention) and composition Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 An additional sample with S5I was annealed at 500° C. for 24 hours (step (c), heating and cooling rates of 5° C. / min).

[0119] Composition Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 For S5I, an additional sample was prepared without annealing (step (c)).

[0120] Composition Li 6.5 P0.25 S 0.25 Ge 0.25 Sb 0.25 For S5I, additional samples were prepared to investigate the effect of alternative cooling conditions in step (c) (slow cooling for 48 hours or quenching in liquid nitrogen).

[0121] 2. Structural analysis Powder X-ray diffraction (XRD) measurements were performed at room temperature on a STADI P diffractometer (STOE) using Mo-Kα1 radiation (λ = 0.70931715 Å) and a Mythen1k detector (Dectris) equipped with an annular collimator. Samples were sealed in borosilicate capillaries (inner diameter 0.48 mm and wall thickness 0.01 mm, Hilgenberg) under argon atmosphere.

[0122] General formula Li (6+m) P (1-3n )Si n Ge n Sb n The three different materials with compositions according to S5I showed typical single-phase XRD patterns indicative of the so-called cubic argyrodite structure (Figure 1a). Furthermore, as the phosphorus content decreased, a progressive shift of the reflections towards lower 2θ angles was observed (Figure 1b), indicating the existence of solid solutions between the different cationic substituents (P, Si, Ge and Sb).

[0123] Composition Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 For the S5I material, the XRD patterns of a sample obtained without annealing (without step (c)) were compared with a sample that was annealed (step (c)) and then allowed to cool naturally. After annealing, the reflections in the XRD pattern were more clearly defined, indicating improved crystallinity compared to after ball milling without annealing (Figure 2).

[0124] The cooling conditions (natural cooling, rapid cooling, or slow cooling over 48 hours) were: Li 6.5 P 0.25 S0.25 Ge 0.25 Sb 0.25 The XRD pattern of S5I showed no significant effect.

[0125] Figure 3 shows the Li 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 S5I and Li 6.7 S 0.33 Ge 0.33 Sb 0.33 The XRD patterns of LiPS5I (all annealed at 500 °C) with four different elements (P, Si, Ge, Sb) in the lattice sites (occupied by phosphorus in the parent material L6PS5I) are shown (see Figure 3). 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 The XRD pattern of S5I showed a single phase with only traces of educts LiI and Li2S. Li2S has three different elements (Si, Ge, Sb) in the lattice sites (occupied by phosphorus in the parent material L6PS5I). 6.7 S 0.33 Ge 0.33 Sb 0.33 The XRD pattern of S5I showed multiple phases including LiSbS2 and some unknown phases, so it is believed that the presence of four different elements (P, Si, Ge, Sb) in lattice sites (occupied by phosphorus in the parent material L6PS5I) stabilizes the entropy resulting in a single phase.

[0126] 3. Ionic Conductivity Electrochemical impedance spectroscopy (EIS) was measured using a custom-made two-electrode cell containing two stainless steel plungers and a PEEK sleeve with an inner diameter of 10 mm. Approximately 150 mg of powder was introduced into the cell and pressed at 3 t for 3 min (i.e., cold pressing). EIS was measured from 0.1 Hz to 7 MHz at room temperature with a voltage amplitude of 20 mV using an SP-200 potentiostat (BioLogic). An external pressure of 2 t was applied during the measurements.

[0127] The results are shown in Table 1 below.

[0128] [Table 1]

[0129] The data presented in Table 1 reveal the following trends:

[0130] General formula Li (6+m) P (1-3n) S n Ge n Sb n For three different materials with compositions according to S5I, the ionic conductivity increases as the phosphorus content decreases.

[0131] Surprisingly, the cooling conditions (natural cooling, rapid cooling, or slow cooling over 48 hours) were 6.5 P 0.25 S 0.25 Ge 0.25 Sb 0.25 It appears that natural cooling (cooling rate of about 5°C per minute) has a large effect on the ionic conductivity of S5I, and thus natural cooling (cooling rate of about 5°C per minute) appears to be advantageous compared to both rapid and slow cooling.

Claims

1. Formula (IIc) Li ６＋ｍ P １－３ｎ 71 （ｚ１）＋ ｎ 72 （ｚ２）＋ ｎ 73 （ｚ３）＋ ｎ Y ５ X (9ｩc) (In the formula, X is selected from F, Cl, Br and I; Y is selected from O, S, Se and Te; M1 （ｚ１）＋ ~M3 （ｚ３）＋ is Si ４＋ , Ge ４＋ , Sn ４＋ and Sb ５＋ is selected from the group consisting of n is a number ranging from 0.05 to 0.3; and m = 5 - [5 * (1 - x) + n * (z1 + z2 + z3)]. A solid material having a composition according to

2. 2. The solid material of claim 1, wherein X is I or Y is S.

3. 2. The solid material of claim 1, wherein X is I and Y is S.

4. 2. The solid material of claim 1, wherein n is a number in the range of 0.2 to 0.

28.

5. M1 （ｚ１）＋ is Si ４＋ and M2 （ｚ２）＋ Ge ４＋ and M3 （ｚ３）＋ is Sb ５＋ 2. The solid material of claim 1, wherein X is I (iodine) and Y is S.

6. 10. The solid material of claim 1, wherein the material comprises a crystalline phase having an argyrodite structure.

7. 10. A method for producing a solid material according to claim 1, comprising the steps of: (a) Precursors of: (1) One or more of oxides, sulfides, selenides, and tellurides of lithium; (2) one or more of oxides, sulfides, selenides, and tellurides of phosphorus; (3) one or more compounds LiX, where X is selected from F, Cl, Br, and I; (4) Si ４＋ , Ge ４＋ , Sn ４＋ , and Sb ５＋ a compound selected from the group consisting of oxides, sulfides, selenides and tellurides of three cations selected from the group consisting of: (5) Optionally, one or more of S, Se, and Te in elemental form. providing a reaction mixture comprising: wherein the molar ratios of all elements in the reaction mixture are selected to be consistent with formula (IIc); (b) reacting the precursor to obtain a solid material having a composition according to formula (IIc) A method comprising:

8. 8. The method of claim 7, wherein in step (a) The precursor (1) is Li ２ S, and / or The precursor (2) is P ２ S ５ and / or the precursor (3) is LiI, and / or The precursor (4) is SiS ２ , GeS ２ , SnS ２ and Sb ２ S ３ and / or The precursor (5) is elemental sulfur or is absent; method.

9. 8. The method of claim 7, wherein in step (a) The precursor (1) is Li ２ It consists of S, The precursor (2) is P ２ S ５ It consists of The precursor (3) is composed of LiI, The precursor (4) is SiS ２ , GeS ２ , and Sb ２ S ３ It consists of The precursor (5) consists of elemental sulfur or is absent; method.

10. 8. The method of claim 7, comprising the steps of: (a) preparing or providing a solid reaction mixture comprising a precursor as defined in claim 7; (b1) heat treating the reaction mixture at a temperature ranging from 200° C. to 600° C. for a total period of 1 to 48 hours or more to form a reaction product, and cooling the reaction product to obtain a solid material having a composition according to formula (IIc). A method comprising:

11. 8. The method of claim 7, comprising the steps of: (a) preparing or providing a solid reaction mixture comprising a precursor as defined in claim 7; (b2) mechanochemically treating the solid reaction mixture to obtain a solid material having a composition according to formula (IIc) A method comprising:

12. 12. The method of claim 11, comprising the steps of: (c) annealing the solid material obtained by the mechanochemical treatment at a temperature ranging from 200°C to 600°C for a total time period ranging from 1 to 48 hours, and cooling the annealed solid material. The method further comprises:

13. A solid structure for an electrochemical cell, the solid structure being selected from the group consisting of a cathode, an anode and a separator, comprising the solid material of claim 1 or 2.

14. 10. An electrochemical cell comprising the solid-state material of claim 1.

15. 15. An electrochemical cell according to claim 14, wherein the solid material according to claim 1 is a component of the solid structure defined in claim 13.

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