Multi-doped garnet electrolyte

Abstract

In one aspect, the present invention provides a solid electrolyte material. The solid electrolyte material includes a composition of chemical formulas (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII) as described herein. Another aspect provides a method for manufacturing a green body. A further aspect provides a method for manufacturing a sintered solid electrolyte material. Chemical formula Li 7-3x+y-z Al x La 3-y Ca y Zr 2-z Ta z O 12 of a solid electrolyte material, wherein 0

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 356,890, filed on June 29, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] Government License Rights This invention was made with government support under Contract No. SP4701 - 20 - F - 0115 awarded by the Defense Logistics Agency. The United States government has certain rights in this invention.

Background Art

[0003] This disclosure relates to solid electrolyte materials suitable for use in solid - state lithium batteries.

[0004] All - solid - state lithium batteries are made by replacing the highly flammable and unstable liquid electrolytes contained in conventional lithium - ion batteries. Solid electrolyte materials can have many advantages over liquid electrolyte materials. For example, solid electrolyte materials can be non - flammable, stable at high temperatures without decomposition, and electrochemically stable with respect to lithium metal and / or high - voltage cathodes. This improved stability allows all - solid - state batteries to exhibit higher energy density and power density, enabling the use of desirable electrode materials that were previously difficult to use with liquid electrolytes.

[0005] An ideal solid electrolyte material has several combined characteristics. For example, an ideal solid electrolyte material can exhibit high ionic conductivity, low / negligible electronic conductivity, high chemical and electrochemical stability, resistance to lithium dendrite propagation, and efficient and low-cost manufacturability. In the case of oxide-based solid electrolyte materials, it is necessary that the material is lightweight, contains little or no secondary phase (i.e., phases other than cubic garnet), can be manufactured with low porosity or be non-porous, and can be sintered in a shorter time and at a lower temperature. If pores exist in the separator layer of a battery cell, the pores can function as a path for lithium dendrites to propagate through the solid electrolyte material, which may cause a short circuit and thus adversely affect the electrochemical performance of the cell and / or battery. Similarly, the secondary phase may not have the same chemical or electrochemical stability as the primary phase (i.e., cubic garnet phase) of the solid electrolyte material. For this reason, the secondary phase may react with the active electrode material during cell cycling, become electronically conductive, and cause a short circuit.

[0006] Lithium lanthanum zirconium oxide (LLZO) is recognized as a solid electrolyte material that may possess many desirable characteristics for use in batteries. When properly processed, LLZO has high Li + ion conductivity (>10 -5 S / cm) and low electronic conductivity (~10 -8 S / cm), and is chemically and electrochemically stable against lithium metal. However, it is difficult to manufacture LLZO into a solid with low porosity and without harmful secondary phases. Generally, LLZO sintering is carried out at a high temperature (e.g., 1200 °C), for a long time (e.g., 6 hours or more), and in the presence of excess lithium to compensate for lithium loss. The lithium loss is due to the volatility of lithium at high temperatures.

[0007] Therefore, there remains a need to provide improved solid electrolyte materials. SUMMARY OF THE INVENTION

[0008] The present invention provides a solid electrolyte material comprising a composition of formula (I). M1 7-x D1 a M2 3-y D2 b M3 2-z D3 c O 12-w D4 d ···(I) Wherein M1 is Li, M2 is La, M3 is Zr, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, N, P, or any combination thereof, 0 ≦ w ≦ 2, -0.5 < x ≦ 3, 0 ≦ y ≦ 3, 0 ≦ z ≦ 2, 0 ≦ a ≦ 2, 0 ≦ b ≦ 3, 0 ≦ c ≦ 2, and 0 ≦ d ≦ 2, where at least one of a, b, c, and d is not 0.

[0009] In some embodiments, 0 < y ≦ 3, 0 < z ≦ 2, 0 < a ≦ 2, and 0 < b ≦ 3, and 0 < c ≦ 2. In some embodiments, 0 ≦ w ≦ 1. In other embodiments, 0 ≦ w ≦ 0.5. Also, in some embodiments, 0 ≦ w ≦ 0.1.

[0010] In some embodiments, 0 ≦ x ≦ 1. In other embodiments, 0.2 ≦ x ≦ 0.8.

[0011] In some embodiments, 0 < y < 3. In other embodiments, 0 < y < 1. In some embodiments, 0 < y < 0.5. Also, in some embodiments, 0.05 ≦ y ≦ 0.25.

[0012] In some embodiments, 0 < a ≦ 1. In other embodiments, 0 < a < 0.24.

[0013] In some embodiments, 0 < b < 3. In other embodiments, 0 < b < 1. In some embodiments, 0 < b < 0.5. Also, in some embodiments, 0.05 ≦ b ≦ 0.25.

[0014] In some embodiments, 0 < c ≦ 0.7. In other embodiments, 0 < c ≦ 0.5. Also, in some embodiments, 0.2 ≦ c ≦ 0.5.

[0015] In some embodiments, 0 ≦ d ≦ 1. In other embodiments, 0 ≦ d ≦ 0.5. Also, in some embodiments, 0 ≦ d ≦ 0.1.

[0016] In some embodiments, D1 is Al, Fe, Zn, and Ga, or any combination thereof. For example, D1 may be Al. In other embodiments, D1 is Fe. In some embodiments, D1 is Zn. Also, in some embodiments, D1 is Ga.

[0017] In some embodiments, D2 is Ca, Sr, Ba, Bi, and Nd, or any combination thereof. For example, D2 may be Ca. In some embodiments, D2 is Sr. In other embodiments, D2 is Ba. In some embodiments, D2 is Bi. Also, in some embodiments, D2 is Ba.

[0018] In some embodiments, D3 is Ta, Nb, W, Ti, and Mo, or any combination thereof. For example, D3 may be Ta. In some embodiments, D3 is Nb. In other embodiments, D3 is W. In some embodiments, D3 is Ti. Also, in some embodiments, D3 is Mo.

[0019] In some embodiments, 7 - x = 7 - a(vD1)+b(3 - vD2)+c(4 - vD4)-d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d. In some embodiments, 0 ≦ x ≦ 1.0.

[0020] Another aspect of the present invention provides a solid electrolyte material comprising a composition of Chemical Formula (II). Li 7-x D1 a La 3-y D2 b Zr 2-z D3 c O 12-w D4 d ···(II) Wherein, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, or any combination thereof, 0 ≦ w < 2, -0.5 < x ≤ 3, 0 < y ≤ 3, 0 < z ≤ 2, 0 < a ≤ 2, 0 < b ≤ 3, 0 < c ≤ 2, and 0 ≤ d ≤ 2.

[0021] In some embodiments, 0 ≤ w ≤ 1. In other embodiments, 0 ≤ w ≤ 0.5. Also, in some embodiments, 0 ≤ w ≤ 0.1.

[0022] In some embodiments, 0 < x ≤ 1.5. In some embodiments, 0.5 < y ≤ 2. Also, in some embodiments, 0.5 < z ≤ 1.5.

[0023] In some embodiments, 0 < a < 0.24. In some embodiments, 0 < b ≤ 2. Also, in some embodiments, 0 < c ≤ 1.5.

[0024] In some embodiments, 0 ≤ d ≤ 1. In other embodiments, 0 ≤ d ≤ 0.5. Also, in some embodiments, 0 ≤ d ≤ 0.1.

[0025] In some embodiments, D1 is Al or Ga. For example, D1 may be Al. In other embodiments, D1 is Ga.

[0026] In some embodiments, D2 is Ca, Sr, Ba, or any combination thereof. For example, D2 may be Ca. In other embodiments, D2 is Sr. Also, in some embodiments, D2 is Ba.

[0027] In some embodiments, D3 is Ta, Nb, W, Ti, and Mo, or any combination thereof. For example, D3 may be Ta. In some embodiments, D3 is Nb. In other embodiments, D3 is W. In some embodiments, D3 is Ti. Also, in some embodiments, D3 is Mo.

[0028] In some embodiments, D4 is F, Cl, or any combination thereof. For example, D4 may be F. In other embodiments, D4 may be Cl.

[0029] In some embodiments, 0 < a ≤ 0.25. In some embodiments, 0 < b ≤ 0.5. In some embodiments, 0 < c ≤ 1.0. Also, in some embodiments, 0 ≤ d ≤ 0.25.

[0030] In some embodiments, 0 ≤ x ≤ 1.0. In some embodiments, 0 ≤ y ≤ 0.5. In some embodiments, 0 ≤ z ≤ 1.0. Also, in some embodiments, 0 ≤ w ≤ 0.25.

[0031] In some embodiments, 7 - x = 7 - a(vD1) + b(3 - vD2) + c(4 - vD4) - d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d. In some embodiments, 0 ≤ x ≤ 1.0.

[0032] Another aspect of the present invention provides a solid electrolyte material comprising a composition of Chemical Formula (IV). Li n B x vB La 3-y C y vC Zr 2-z D z vD O 12-a G a ···(IV) Wherein, n = 7 - x(vB) + y(3 - vC) + z(4 - vD) - a / 2, where vB is the oxidation state of B, vC is the oxidation state of C, vD is the oxidation state of D, B is H + 、Al 3+ 、Ga 3+ 、Fe 3+ 、Zn 2+, Ge 4+ or any combination thereof, C is Ca 2+ , Ba 2+ , Sr 2+ , Mg 2+ , Rb + , Ce 4+ or any combination thereof, D is Ta 5+ , Y 3+ , Mo 6+ , Nb 5+ , W 6+ , Ge 4+ , Ti 4+ or any combination thereof, G is F - , Cl - , Br - , I - or any combination thereof, 0 < x < 0.24, 0 < y ≤ 1.0, 0 < z ≤ 1.0, and 0 ≤ a ≤ 1.0.

[0033] In some embodiments, B is Al 3+ . In some embodiments, C is Ca 2+ . In some embodiments, D is Ta 5+ , Nb 5+ , Ti 4+ or any combination thereof. Also, in some embodiments, D is Ta 5+ .

[0034] In some embodiments, 0 < x < 0.15. In other embodiments, 0.02 < x < 0.10.

[0035] In some embodiments, 0 < y < 0.50. In other embodiments, 0.1 < y < 0.30. Also, in some embodiments, 0.15 < y < 0.28.

[0036] In some embodiments, 0 < z < 0.70. In other embodiments, 0.3 < z < 0.6. Also, in some embodiments, 0.4 < z < 0.55.

[0037] In some embodiments, 0 ≦ a < 0.1. In other embodiments, 0 ≦ a < 0.05. Also, in some embodiments, x, y, z, and a are selected such that 6 ≦ n ≦ 7.

[0038] In one aspect, the present invention provides a solid electrolyte material comprising a composition of chemical formula (V). Li 7-x B a La 3-y C b Zr 2-z D c O 12 ···(V) Wherein, B is Al or Ga, C is Ca, Sr, Ba, or Mg, D is Ta, Nb, W, Mo, or Ti, 0 ≦ x ≦ 1, 0 < a < 0.24, 0 < y ≦ 0.5, 0 < b ≦ 0.5, 0 < z ≦ 1, and 0 < c ≦ 1.

[0039] Another aspect of the present invention provides a solid electrolyte material comprising a composition of chemical formula (VI). Li 7+y-z La 3-y Ca y Zr 2-z Ta z O 12 ···(VI) Wherein, 0 < y < 0.3, and 0.2 < z < 0.6.

[0040] In another aspect, the present invention provides a solid electrolyte material comprising a composition of chemical formula (VII). Li 7-3x+y-z Alx La 3-y Ca y Zr 2-z Ta z O 12 ···(VII) wherein 0 < x < 0.15, 0 < y < 0.3, and 0.2 < z < 0.6.

[0041] Another aspect of the present invention provides a solid electrolyte material comprising a composition of Chemical Formula (VIII). Li 7-3x+y-z B x La 3-y Ca y Zr 2-z Ta z O 12 ···(VIII) wherein B is Al, 0 ≦ x < 0.25, 0 < y ≦ 0.5, and 0 < z ≦ 1.

[0042] In some embodiments, 0 ≦ x < 0.15. In other embodiments, x is 0. In some embodiments, 0 < x < 0.25.

[0043] In some embodiments, 0 < y < 0.3. In other embodiments, 0.2 < z < 0.6.

[0044] In some embodiments, the solid electrolyte material comprising a composition of Chemical Formula (I), (II), (III), (IV), (V), (VI), (VII), or (VIII) has a Li -4 conductivity of at least about 4×10 + S / cm.

[0045] Another aspect of the present invention provides an electrode for a solid battery comprising a solid electrolyte material comprising a composition of Chemical Formula (I), (II), (III), (IV), (V), (VI), (VII), or (VIII).

[0046] Another aspect of the present invention provides a two-layer solid electrolyte structure including a porous layer and a high-density layer. At least one of the porous layer and the high-density layer includes a solid electrolyte material composed of a composition of chemical formulas (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII).

[0047] Another aspect of the present invention provides a three-layer solid electrolyte structure including a first porous layer, a high-density layer, and a second porous layer. At least one of the first porous layer, the high-density layer, and the second porous layer includes a solid electrolyte material composed of a composition of chemical formulas (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII).

[0048] Another aspect of the present invention provides a solid battery including the solid electrolyte material described herein, the electrode described herein, the two-layer solid electrolyte structure described herein, or the three-layer solid electrolyte structure described herein.

[0049] In some embodiments, the solid electrolyte material is sintered. In some embodiments, the sintered electrolyte material is incorporated into a ceramic separator. In some embodiments, the sintered electrolyte material is incorporated into a host structure for lithium metal plating and stripping. In some embodiments, the sintered electrolyte material physically contacts the cathode material and the anode material to form a combination of an electrode pair and a separator layer.

[0050] In other aspects, the present invention provides a method for forming a green body including the solid electrolyte material described herein.

[0051] In other aspects, the present invention provides a method for forming a green body including the sintered solid electrolyte material described herein.

[0052] The following figures are provided by way of example and are not intended to limit the scope of the claimed invention.

Brief Description of the Drawings

[0053]

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DETAILED DESCRIPTION OF THE INVENTION

[0054] The present invention provides a solid electrolyte material, a battery cell including such a solid electrolyte material, and a method of forming such a solid electrolyte material.

[0055] As used herein, unless otherwise specified, the following definitions shall apply.

[0056] I. Definitions The terms used in this specification are for the purpose of describing particular exemplary configurations only and are not intended to be limiting. As used herein, the singular forms of the articles "a," "an," and "the" may be intended to include the plural as well, unless the context clearly dictates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and thus specify the presence of stated features, steps, acts, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, acts, elements, components, and / or groups thereof. Method steps, processes, and acts described herein should not be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically specified as the order of performance. Additional or alternative steps may be used.

[0057] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. The terms "first," "second," etc., and other numerical terms do not imply an order or sequence unless clearly indicated by the context. Thus, a first element, component, region, layer, or section described hereinafter may be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary configuration.

[0058] As used herein, when an element is "in contact with", "engaged with", "connected to", "attached to", or "coupled to" another element, it may be in direct contact with, engaged with, connected to, attached to, or coupled to the other element, or there may be intervening elements. In contrast, when an element is "in direct contact with", "in direct engagement with", "in direct connection with", "in direct attachment to", or "in direct coupling to" another element, there can be no intervening element or layer. Other words used to describe the relationship between elements should be interpreted in the same way (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0059] As used herein, the term "doping" and its derivatives refer to the presence or arrangement of atoms other than the basic atoms in the crystal structure of the garnet material. For example, in the case of the basic structure of Li7La3Zr2O 12 (LLZO), some or all of the lithium, some or all of the lanthanum, some or all of the zirconium, and / or some or all of the oxygen can be replaced with other atoms. Such substitution can be performed after or during the formation of the basic structure. Similar substitutions can be made for other garnet-based structures.

[0060] As used herein, the term "garnet" refers to the cubic or tetragonal structure of LLZO.

[0061] As used herein, the term "solid electrolyte material" refers to a material suitable for use in a solid-state battery cell. The solid electrolyte material consists of a composition of formula (I), (II), (III), (IV), (V), (VI), (VII), or (VIII).

[0062] As used herein, the term "green body" refers to an unfired body (e.g., a tape and / or film) containing a solid electrolyte material.

[0063] As used herein, the term "powder bed" refers to a lithium-containing powder that is near a component or green body that is heat-treated by sintering or other methods. The powder may be composed of undoped LLZO, doped LLZO, or other materials containing lithium. This functions as a reservoir for supplying additional lithium during the heat treatment and can suppress the loss of lithium from the component or green body during sintering or other thermal processes.

[0064] As used herein, the term "porosity" refers to the volume ratio of the space not occupied by the material of interest (e.g., a solid electrolyte material) to the total volume of the material of interest, unless the context indicates otherwise. In some embodiments, the unoccupied space at the edges of the material of interest (e.g., depressions on the outer surface of the material of interest) is not included in the determination of porosity.

[0065] As used herein, the term "stabilization of the cubic phase" refers to stabilizing the cubic crystal structure of a solid electrolyte material and preventing the transition from the cubic phase to the tetragonal phase (e.g., during processing), unless the context indicates otherwise. Stabilization may be complete (i.e., no transition) or partial by reducing the amount of transition that occurs compared to the condition without the same material and the same amount of stabilizing material.

[0066] As used herein, the term "secondary phase" refers to an undesirable composition formed within a structure, unless the context indicates otherwise. The secondary phase can be non-garnet or garnet. In the case of secondary phase garnet, its composition may be different from that desired, or it may have dopants located at the wrong sites. In many cases, the secondary phase can impair the structural or performance characteristics of the solid electrolyte material. For example, the secondary phase can cause an increase in impedance or weakness in the structural properties of the solid electrolyte material. Exemplary secondary phases include, but are not limited to, Li2O, Li2CO3, Al2O3, LiAlO2, La2Zr2O7, LaTaO4, CaO, CaCO3, ZrO2, Li2ZrO3, Li3BO3, Li-Ca-B-O, and the like. Multiple secondary phases can be present.

[0067] II. Solid Electrolyte Material In one aspect, the present invention provides a solid electrolyte.

[0068] A solid electrolyte ideal for battery applications should have high ionic conductivity (greater than 10 -4 S / cm), low processing energy and cost, minimal waste in manufacturing, and high chemical and electrochemical stability. The physical and electrochemical properties of a solid electrolyte are mainly determined by the composition, crystal phase, and microstructure of the sintered body. These properties include electronic and ionic conductivity, electrochemical stability (with respect to lithium metal and other cathode and anode materials), sintering temperature, lithium vapor pressure, and mechanical properties. Processing conditions such as sintering time, sintering temperature, heating rate, and additives such as sintering aids also affect the physical and electrochemical properties of the solid electrolyte.

[0069] The elemental doping of LLZO can be used to adjust these properties. Generally, the use of a single dopant changes the properties of LLZO, some of which are improved in a desirable way, while some are deteriorated and / or unaffected. The use of multiple dopants allows for additional control of the final properties by combining them so that they do not interfere with each other adversely. When using two dopants, the additional degrees of freedom can be used to offset undesirable changes while improving some of the material properties in a desirable way. When using three or more dopants, if the final material remains stable with all dopants added, an optimized composition that is nearly ideal in all categories can be produced. The best properties of LLZO reported to date have been achieved by doping with one or two elements.

[0070] Generally, each site within a crystal has a limit to the number of substitutions possible for each dopant associated with that site before a secondary phase appears. In some cases, using dopants at multiple crystal sites can broaden the solubility window and allow for additional amounts of dopants compared to single-site doping without the formation of secondary phases and / or impurities. Secondary phases and / or impurities can reduce the ionic conductivity, interact or react with the Li metal, and / or cause a short circuit during manufacturing or operation. Next, doping three elements at three sites allows for the introduction of a greater total amount of dopants compared to the two-site case, and the same is true for additional dopants.

[0071] LLZO garnet electrolytes have two crystal phases: cubic and tetragonal. The cubic phase has an ionic conductivity two orders of magnitude higher than that of the tetragonal phase and is the desired phase for battery applications. The cubic phase has a higher entropy than the tetragonal phase and is stable at higher temperatures. However, the undoped LLZO tetragonal phase is stable at room temperature. Doping with Ta or Al has been shown to stabilize the cubic phase at room temperature. Other elements such as Ga and Nb are also used to successfully stabilize the cubic phase of LLZO. Generally, these dopants create lithium vacancies, increase the entropy of mixing, and contribute to the stabilization of the cubic phase. When dopants are used to stabilize the cubic phase of LLZO, it has been demonstrated that the ionic conductivity at room temperature exceeds 10 -4 S / cm.

[0072] To sinter LLZO, high temperatures (>1200 °C) are typically required to sinter the ceramic, i.e., to create a fine structure with a low porosity and a uniform composition. In the case of LLZO, lithium in the composition has a very high vapor pressure at these temperatures. Evaporation of Li creates a composition gradient, which can prevent proper sintering and firing and cause decomposition of the garnet crystal structure. A powder bed containing excess lithium is usually used in the form of additional LLZO powder but is typically used in the sintering environment to limit the loss of lithium from the components being sintered. After sintering, the powder bed is lithium-deficient and is generally disposed of as waste. Additionally, a porous garnet layer can collapse at these high temperatures in some embodiments and under some conditions, which can be due to liquid-phase sintering or softening / creep of LLZO at the sintering temperature. Reducing the sintering temperature while still achieving the desired (low or high) porosity and single-phase fine structure reduces both the energy cost and the material cost by reducing or eliminating the need for a powder bed.

[0073] Some dopants have little effect on the sintering temperature compared to undoped LLZO. However, Al-doped LLZO has been shown to have a lower sintering temperature (i.e., less than 1200 °C) and improved densification (i.e., lower porosity after sintering). Without wishing to be bound by theory, these properties of Al-doped LLZO may be attributed to the formation of a transient liquid phase containing Li and Al that changes the sintering rate by liquid phase sintering. Alternatively, these properties of Al-doped LLZO may also be attributed to how Al affects the volatility of lithium within LLZO. The amount of Al required to stabilize the cubic phase is more than about 0.15 moles of Al per formula unit (pfu), i.e., Li 6.55 Al 0.15 La3Zr2O 12 is. However, the amount of Al required to act as a sintering aid can be much less. When LLZO is doped with an amount of Al greater than about 0.15 pfu, Al-rich regions are observed at the grain boundaries and correlate with instability to lithium metal during cell cycling.

[0074] Often, Al is introduced into the LLZO material during firing or sintering by using an Al2O3-rich crucible that is reactive to LLZO. When using a very high purity Al2O3 crucible during firing, for example, up to about 0.24 pfu or more of Al can be added to the LLZO. The amount of Al cannot be precisely controlled in this type of process. Instead, in some embodiments, the addition of a controlled amount of Al may be achieved by firing and / or sintering on a substrate containing less than about 5% Al2O3 using a desired amount of an Al-containing precursor material prior to firing.

[0075] In some embodiments, to prevent segregation at grain boundaries, the Al content is limited to be significantly less than about 0.1 pfu. Without wishing to be bound by theory, less than about 0.15 pfu, less than about 0.12, or less than about 0.10 pfu, and in some embodiments, the presence of Al from about 0.01 pfu to about 0.08 pfu is thought to significantly improve densification and reduce the porosity of sintered LLZO without forming unstable secondary phases.

[0076] Furthermore, without wishing to be bound by theory, limiting Al doping to less than about 0.15 pfu (e.g., less than about 0.12 pfu, less than about 0.10 pfu, and in some embodiments, from about 0.01 pfu to about 0.08 pfu) is thought to benefit LLZO by acting as a sintering aid, minimizing porosity without creating Al-rich grain boundaries, and beneficially reducing the sintering temperature. However, this small amount of Al alone is not sufficient to stabilize the cubic phase of LLZO. Additional dopants can be used in combination with Al to stabilize the cubic phase. For example, Ta can be co-doped with Al to stabilize the cubic phase, where Al is doped at the Li site and Ta is doped at the Zr site. Generally, doping of Ta greater than about 0.2 pfu (e.g., greater than about 0.35 pfu, or greater than about 0.4 pfu and less than about 0.6 pfu) can be used to stabilize the cubic phase. Al 3+ and Ta 5+ are both in a higher oxidation state than the elements they replace (Li 1+ and Zr 4+ ), respectively), so this level of doping creates a large number of Li vacancies, along with a decrease in the amount of lithium in the crystal structure. This reduction in lithium can have an adverse effect on physical properties (e.g., Li + conductivity) because significantly less lithium is present for conduction. A third dopant with a lower valence than La 3+ at the La site, such as Ca 3+ or Sr 2+ or Sr 2+Adding it can fill the vacancies created by other dopants and allow more lithium to be added to the composition. For example, in the case of a system doped with about 0.1 pfu of Al and about 0.4 pfu of Ta, about 0.7 pfu of lithium vacancies are created and about 6.3 pfu of Li remains. When about 0.2 pfu of Sr is doped at the La site, about 6.5 pfu of Li results in the correct stoichiometry (i.e., Li 6.5 Al 0.1 La 2.8 Sr 0.2 Zr 1.6 Ta 0.4 O 12 ).

[0077] In some embodiments, when the type and amount of dopant are appropriately selected, an increase in conductivity can be achieved that exceeds what can be found with only two dopants. In this example, the first dopant is used to stabilize the cubic phase, another dopant is used as a sintering aid, and a third dopant is used to bring the lithium content to a desired level. By doping with the three elements described herein, the sintering temperature can be reduced, densification can be improved / porosity can be reduced with little or no secondary phase detected, and the Li + ion conductivity can be optimized without sacrificing other beneficial properties of LLZO. When doping with multiple elements, unexpected changes in mechanical properties such as flexural strength, modulus of elasticity, or hardness, or unexpected changes in physical properties such as reduction in lithium volatility at high temperatures (e.g., during sintering and firing), requirements for lower sintering temperatures, formation of low temperature eutectic phases, or unexpected changes in electrochemical properties such as significant changes in ion conductivity or electronic conductivity, stability to water, air, CO2, other materials, and other unexpected advantages, an unexpected "cocktail" effect may occur.

[0078] Different dopants, or more than three additional dopants, can be used to further adjust the properties as needed. As an example, the ability to control properties such as increasing porosity may sometimes be desirable. By appropriately changing the composition of LLZO, the sintering temperature and densification rate can be modified, enabling control of porosity. Furthermore, a high-density porous bilayer microstructure (i.e., a low-porosity layer adjacent to a high-porosity layer) can be achieved when the optimal composition for each layer is appropriately selected.

[0079] This approach provides a multi-element doping strategy using LLZO containing three or more dopants to optimize the combination of the above-described physicochemical properties for use as a lithium-conductive solid electrolyte. After sintering, the composition of certain embodiments has a high Li -4 conductivity exceeding 4×10 + S / cm, a very low and controllable porosity, and may have little or no detectable secondary phase. Furthermore, certain embodiments along the multi-element doping strategy may have unexpected properties such as low volatility of lithium at high temperatures. This can provide the ability to sinter in a state where less (or no) excess lithium above the stoichiometric amount is required to compensate for lithium loss. This property can also provide the ability to sinter without using a powder bed or other lithium source outside the green body to compensate for lithium loss during sintering.

[0080] When using two or more dopants, the entropy of mixing tends to be higher than when using two or fewer dopants, based on the following equation.

Equation

[0081] Since the cubic phase of garnet is a higher entropy phase than the tetragonal phase, the use of three or more dopants can enhance the stability of the cubic phase. Further, by using dopants that create lithium or oxygen vacancies in the crystal structure, the entropy can also be increased. This can result in a lower firing or sintering temperature for cubic phase LLZO. Disorder is favorable for the more symmetric cubic phase. The use of three or more dopants increases the disorder compared to two, one, or no dopants, while still maintaining a single cubic garnet phase, e.g., without or with a reduced formation or presence of secondary or impurity phases.

[0082] In certain embodiments, some of the O 2- atoms can be replaced with one or more anions to dope the crystal structure with anions. Examples of anions include F - , Cl - , and any combination thereof. Anion doping can have a similar effect as cation doping. Anion doping can have the additional advantage of making the garnet surface more stable against reactions in both the fired powder product and the sintered product. The product can be more stable against air, i.e., ambient H2O and CO2, and have a more stable interface with the electrode material.

[0083] This approach includes a method for manufacturing a multi-doped LLZO garnet composition. In some embodiments, the composition may be made by blending precursors together and firing at a set temperature and set amount of time to produce a doped garnet material. The precursors can be salts, carbonates, oxides, nitrates, and / or hydroxides of the elements desired in the doped garnet material. After firing, the doped garnet material can optionally be milled to reduce the particle size. The doped garnet material can be fabricated into a desired structure, such as by sintering or forming a composite with other materials including, but not limited to, polymers, ceramics, glasses, conductive carbon, or other ion-conductive materials. Firing and sintering may be accomplished in the same or separate processing steps.

[0084] The approach of the present invention has several significant advantages compared to modern LLZO technologies such as "Co-sinterable lithium garnet-type oxide electrolyte with cathode for all-solid-state lithium ion battery" by S. Ohta, et al. (J. Power Sources, Vol. 265, pp. 40-44, 2014) and U.S. Application Publication 2015 / 0056519, filed on August 20, 2014, all of which are incorporated by reference in their entirety. First, the pre-sintered Ohta powder product is doped with two elements (Ca and Nb) instead of three or more. In preparing for sintering, Ohta teaches that the powder is mixed with Al2O3 and Li3BO3 as processing additives rather than as substituents or dopants. This is a significant drawback compared to the present approach. When doping with elements such as Al, it is necessary to reduce the corresponding amount of Li from the composition so that while ensuring space for Al to enter the crystal lattice, excess material beyond the stoichiometric composition does not form a secondary phase. Generally, doping is performed during the synthesis or firing step to produce the LLZO product. On the other hand, Ohta teaches that the elements are added as "additives" after the firing step. Furthermore, the Al2O3 and Li3BO3 additives have been shown to remain as secondary phases after sintering rather than forming a single-phase, low-porosity product. This can be seen in Ohta's SEM-EDX images, which clearly show regions with high B and Ca contents separate from the LiLaZrNbAl region. The final composition of Ohta's sintered product is a two-element doped LLZO (doped with Al and Nb) with Li-Ca-BO grain boundary products formed during sintering. The present approach does not have such grain boundary products and does not involve the use of additives containing element B or inorganic elements not already present in the doped LLZO composition.

[0085] This approach has significant advantages over current LLZO technologies such as those disclosed in JP 2021-093308. This reference discloses a method for an aggregate of crystalline particles composed of a fired but un-sintered LLZO material. However, this approach details multi-doped LLZO powders and multi-doped LLZO sintered structures. Further, while this reference discloses a formula that can include three dopants, it does not disclose a doping strategy that provides guidance on the type of each dopant, selection of the amount, and how to balance the dopants with the Li, La, Zr, and O elements in the composition, nor does it disclose any explanation of the relationship between the dopants and their effects on the properties. Further, in all embodiments, two or fewer dopants are used. Thus, this reference does not teach a method for doping LLZO with three or more elements in a meaningful way. This approach teaches a method for producing multi-doped LLZO powder products and sintered products, with a particular emphasis on methods for combining dopants and balancing the composition to achieve a desired result.

[0086] Some embodiments of the present invention provide a solid electrolyte material comprising a composition of chemical formula (I). M1 7-x D1 a M2 3-y D2 b M3 2-z D3 c O 12-w D4 d ···(I) Wherein, M1 is Li, M2 is La, M3 is Zr, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, N, P, or any combination thereof, 0 ≦ w ≦ 2, -0.5 < x ≦ 3, 0 ≦ y ≦ 3, 0 ≦ z ≦ 2, 0 ≦ a ≦ 2, 0 ≦ b ≦ 3, 0 ≦ c ≦ 2, and 0 ≦ d ≦ 2, where at least one of a, b, c, and d is not zero.

[0087] In some embodiments, 0 < y ≦ 3, 0 < z ≦ 2, 0 < a ≦ 2, 0 < b ≦ 3, and 0 < c ≦ 2.

[0088] In some embodiments, 0 ≦ w ≦ 1. In other embodiments, 0 ≦ w ≦ 0.5. Also, in some embodiments, 0 ≦ w ≦ 0.1.

[0089] In some embodiments, 0 ≦ x ≦ 1. In other embodiments, 0 ≦ x ≦ 1. Also, in some embodiments, 0.2 ≦ x ≦ 0.8.

[0090] In some embodiments, 0 < y < 3. In other embodiments, 0 < y < 1. In some embodiments, 0 < y < 0.5. Also, in some embodiments, 0.05 ≦ y ≦ 0.25.

[0091] In some embodiments, 0 < a ≦ 1. In other embodiments, 0 < a < 0.24.

[0092] In some embodiments, 0 < b < 3. In other embodiments, 0 < b < 1. In some embodiments, 0 < b < 0.5. Also, in some embodiments, 0.05 ≤ b ≤ 0.25.

[0093] In some embodiments, 0 < c ≤ 0.7. In other embodiments, 0 < c ≤ 0.5. Also, in some embodiments, 0.2 ≤ c ≤ 0.5.

[0094] In some embodiments, 0 ≤ d ≤ 1. In other embodiments, 0 ≤ d ≤ 0.5. Also, in some embodiments, 0 ≤ d ≤ 0.1.

[0095] In some embodiments, D1 is Al, Fe, Zn, and Ga, or any combination thereof. For example, D1 may be Al. In other embodiments, D1 is Fe. In some embodiments, D1 is Zn. Also, in some embodiments, D1 is Ga.

[0096] In some embodiments, D2 is Ca, Sr, Ba, Bi, and Nd, or any combination thereof. For example, D2 may be Ca. In some embodiments, D2 is Sr. In other embodiments, D2 is Ba. In some embodiments, D2 is Bi. Also, in some embodiments, D2 is Ba.

[0097] In some embodiments, D3 is Ta, Nb, W, Ti, and Mo, or any combination thereof. For example, D3 may be Ta. In some embodiments, D3 is Nb. In other embodiments, D3 is W. In some embodiments, D3 is Ti. Also, in some embodiments, D3 is Mo.

[0098] In some embodiments, 7 - x = 7 - a(vD1)+b(3 - vD2)+c(4 - vD4)-d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d. In some embodiments, 0≦x≦1.0.

[0099] Other embodiments of the present invention provide a solid electrolyte material comprising a composition of Chemical Formula (II). Li 7-x D1 a La 3-y D2 b Zr 2-z D3 c O 12-w D4 d ···(II) Wherein, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, or any combination thereof, 0≦w<2, -0.5<x≦3, 0<y≦3, 0<z≦2, 0<a≦2, 0<b≦3, 0<c≦2, and 0≦d≦2.

[0100] In some embodiments, 0 ≦ w ≦ 1. In other embodiments, 0 ≦ w ≦ 0.5. Also, in some embodiments, 0 ≦ w ≦ 0.1.

[0101] In some embodiments, 0 < x ≦ 1.5. In some embodiments, 0.0 < y ≦ 2. In other embodiments, 0.5 < y ≦ 2. Also, in some embodiments, 0.5 < z ≦ 1.5.

[0102] In some embodiments, 0 < a < 0.24. In some embodiments, 0 < b ≦ 2. Also, in some embodiments, 0 < c ≦ 1.5.

[0103] In some embodiments, 0 ≦ d ≦ 1. In other embodiments, 0 ≦ d ≦ 0.5. Also, in some embodiments, 0 ≦ d ≦ 0.1.

[0104] In some embodiments, D1 is Al or Ga. For example, D1 may be Al. In other embodiments, D1 is Ga.

[0105] In some embodiments, D2 is Ca, Sr, Ba, or any combination thereof. For example, D2 may be Ca. In other embodiments, D2 is Sr. Also, in some embodiments, D2 is Ba.

[0106] In some embodiments, D3 is Ta, Nb, W, Ti, and Mo, or any combination thereof. For example, D3 may be Ta. In some embodiments, D3 is Nb. In other embodiments, D3 is W. In some embodiments, D3 is Ti. Also, in some embodiments, D3 is Mo.

[0107] In some embodiments, D4 is F, Cl, or any combination thereof. For example, D4 may be F. In other embodiments, D4 may be Cl.

[0108] In some embodiments, 0 < a ≤ 0.25. In some embodiments, 0 < b ≤ 0.5. In some embodiments, 0 < c ≤ 1.0. Also, in some embodiments, 0 ≤ d ≤ 0.25.

[0109] In some embodiments, 0 ≤ x ≤ 1.0. In some embodiments, 0 ≤ y ≤ 0.5. In some embodiments, 0 ≤ z ≤ 1.0. Also, in some embodiments, 0 ≤ w ≤ 0.25.

[0110] In some embodiments, 7 - x = 7 - a(vD1) + b(3 - vD2) + c(4 - vD4) - d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d. In some embodiments, 0 ≤ x ≤ 1.0.

[0111] In some embodiments of the composition of formula (II), D1 is Al, Ga, or any combination thereof, 0 < a ≤ 0.15, D2 is Ca, Sr, Ba, or any combination thereof, 0 < b ≤ 0.5, D3 is Ta, Nb, W, Ti, Mo, or any combination thereof, 0 < c ≤ 1.0, D4 is F, Cl, or any combination thereof, 0 ≤ d ≤ 0.25, 0 ≤ x ≤ 1.0, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 1.0, and 0 ≤ w ≤ 0.25.

[0112] Equivalent substitution refers to the case where the dopant has the same charge as the element being substituted, and aliovalent substitution refers to the case where the dopant has a different charge from the element being substituted. In some embodiments, the doping can be aliovalent or equivalent. In some embodiments, there can be a combination of aliovalent and equivalent substitutions in the garnet composition. For example, in equivalent substitution, Y 3+ is substituted by La 3+ or H + is substituted by Li + . In contrast, Ca 2+ can substitute La 3+ , which is an aliovalent substitution. Aliovalent substitution can introduce cation or anion vacancies into the crystal structure. Aliovalent and equivalent doping can be used to strategically control the number of vacancies in the crystal structure and the stoichiometric amounts of other elements in the LLZO composition.

[0113] In some embodiments, the solid electrolyte material comprises the composition set forth in Table 1.

[0114]

Table 1

[0115] In some embodiments, the solid electrolyte material has the chemical formula (III), Li 7-3x-y+z B x La 3-y C y Zr 2-z D z O 12-a G 2a / n ···(III) wherein, B is any trivalent cation (e.g., Al 3+ or Ga 3+ ), or any combination thereof (in some embodiments, the charge can be compensated by removing three Li for one trivalent B), C is any divalent cation (e.g., Mg 2+ ), or any combination thereof, and D is any pentavalent cation (e.g., Nb 5+ ), or any combination thereof, G is any monovalent anion (e.g., F - ), divalent anion (e.g., S 2- ), or trivalent anion (e.g., N 3- ), or G is absent n is the charge of the dopant, 0 < x ≤ 0.5, 0 < y ≤ 3, 0 < z ≤ 2, and 0 ≤ a ≤ 12, In some embodiments, 0 < x < 0.24.

[0116] In other embodiments, 0.1 < y ≤ 1.5. In some embodiments, 0.2 < z ≤ 1. Also, in some embodiments, 0 ≤ a ≤ 0.5.

[0117] In some embodiments, B is Al, Ga, H, Fe, Zn, or any combination thereof. For example, B may be Al. In other embodiments, B is Ga. In some embodiments, B is H. In some embodiments, B is Fe. Also, in some embodiments, B is Zn.

[0118] In some embodiments, D2 is Ca, Mg, Sr, Na, Ce, or any combination thereof. For example, D2 may be Ca. In other embodiments, C is Mg. In some embodiments, C is Sr. In some embodiments, C is Ba. In other embodiments, C is Na. Also, in some embodiments, C is Ce.

[0119] In some embodiments, D is Ta, Y, Mo, Sb, Nb, W, Ge, Ti, or any combination thereof. For example, D is Ta. In other embodiments, D is Y. In some embodiments, D is Mo. In some embodiments, D is Sb. In some embodiments, D is Nb. In other embodiments, D is W. In some embodiments, D is Ge. Also, in some embodiments, D is Ti.

[0120] In some embodiments, G is F, Cl, or any combination thereof, or G is absent. For example, G may be F. In other embodiments, G is Cl. Also, in some embodiments, G is absent.

[0121] In some embodiments of formula (III), B is Al, Ga, H, Fe, Zn, or any combination thereof, 0 < x < 0.24, C is Ca, Mg, Sr, Ba, Na, Ce, or any combination thereof, 0.1 < y ≤ 1.5, D is Ta, Y, Mo, Sb, Nb, W, Ge, Ti, or any combination thereof, 0.2 < z ≤ 1, and G is F, Cl, or any combination thereof, 0 ≤ a ≤ 0.5, or G is absent.

[0122] In some embodiments, the solid electrolyte material has the chemical formula (IV), Li n B x vB La 3-y C y vC Zr 2-z D z vD O 12-a G a ···(IV) wherein, n = 7 - x(vB) + y(3 - vC) + z(4 - vD) - a / 2, vB is the oxidation state of dopant B, vC is the oxidation state of dopant C, vD is the oxidation state of dopant D (in this formula, any changes are vacancies and the charge is balanced by the lithium amount in the formula, but note that a similar approach can also be used by balancing the oxygen amount in the formula), B is H + , Al 3+ , Ga 3+ , Fe 3+ , Zn 2+ , Ge 4+ , or any combination thereof, C is Ca 2+ , Ba 2+ , Sr 2+ , Mg 2+ , Rb + , Ce 4+ , or any combination thereof, D is Ta 5+ , Y 3+ , Mo 6+ , Nb 5+ , W 6+ , Ge 4+ , Ti 4+ , or any combination thereof, G is F - , Cl - , Br - , I - , or any combination thereof, 0 < x < 0.24, 0 < y ≤ 1.0, 0 < z ≤ 1.0, and 0 ≤ a ≤ 1.0.

[0123] For each of the cations listed for B, C, and D, where applicable, different oxidation states of the cation may be used to vary the balance of lithium or oxygen within the system and control the final properties of the solid electrolyte as needed. Further, when combinations of cations are doped at any particular site in the same or different oxidation states, Chemical Formula (IV) may be used with the addition of terms identical to those for the formula for n. For example, if dopants for Li sites B1 and B2 are desired, the formula for n is n = 7 - x1(vB1) - x2(vB2) + y(3 - vC) + z(4 - vD) - a / 2. Similar modifications can be made for multiple C dopants, D dopants, or G dopants, or combinations thereof.

[0124] In some embodiments, B is Al 3+ and in some embodiments, the counterion is Ca 2+ In some embodiments, D is Ta 5+ Nb 5+ Ti 4+ or any combination thereof. For example, D may be Nb 5+ In some embodiments, D is Ti 4+ In some embodiments, D is Ta 5+

[0125] In some embodiments, 0 < x < 0.15. In other embodiments, 0.02 < x < 0.10.

[0126] In some embodiments, 0 < y < 0.50. In other embodiments, 0.1 < y < 0.30. In some embodiments, 0.15 < y < 0.28.

[0127] In some embodiments, 0 < z < 0.70. In other embodiments, 0.3 < z < 0.6. In some embodiments, 0.4 < z < 0.55.

[0128] ​In some embodiments, 0 ≦ a < 0.1. In other embodiments, 0 ≦ a < 0.05. Also, in some embodiments, x, y, z, and a are selected such that 6 ≦ n ≦ 7.

[0129] It should be understood that Chemical Formulas (III) and (IV) can be used as guidance in selecting the compositions of Chemical Formulas (I) and (II), particularly with respect to the composition of specific elements compared to other elements. The relative compositions are useful for producing single-phase garnet solid electrolyte materials.

[0130] In some embodiments, the solid electrolyte material consists of Chemical Formula (V), Li 7-x B a La 3-y C b Zr 2-z D c O 12 ···(V) wherein, B is Al or Ga, C is Ca, Sr, Ba, or Mg, D is Ta, Nb, W, Mo, or Ti, -0.5 < x ≦ 1, 0 < a < 0.24, 0 < y ≦ 0.5, 0 < b ≦ 0.5, 0 < z ≦ 1, and 0 < c ≦ 1.

[0131] In some embodiments, B is Al. In other embodiments, B is Ga.

[0132] In some embodiments, C is Ca. In other embodiments, C is Sr. In some embodiments, C is Ba. Also, in some embodiments, C is Mg.

[0133] In some embodiments, D is Ta. In other embodiments, D is Nb. In some embodiments, D is W. In some embodiments, D is Mo. Also, in some embodiments, D is Ti.

[0134] In some embodiments, 0.2 ≦ x ≦ 0.8. In other embodiments,

[0135] For example, in some embodiments of the composition according to Chemical Formula (V), 0.2 ≦ x ≦ 0.8, 0 < a ≦ 0.15, 0 < y ≦ 0.3, 0 < b ≦ 0.3, 0 < z ≦ 1, and 0 < c ≦ 1.

[0136] In some embodiments, the solid electrolyte material comprises the composition described in Table 2.

[0137]

Table 2

[0138] In other embodiments, the solid electrolyte material consists of the composition of Chemical Formula (VI), Li 7+y-z La 3-y Ca y Zr 2-z Ta z O 12 ···(VI) Wherein, 0 < y < 0.3, and 0.2 < z < 0.6.

[0139] For example, in some embodiments of the composition according to Chemical Formula (VI), 0.1 < y < 0.3, and 0.2 < z < 0.6.

[0140] In some embodiments, the solid electrolyte material consists of the composition of Chemical Formula (VII), Li 7- 3x+y-zAl x La 3-y Ca y Zr 2-z Ta z O 12 ···(VII) wherein 0 < x < 0.15, 0 < y < 0.3, and 0.2 < z < 0.6.

[0141] For example, in some embodiments of the composition according to Chemical Formula (VII), 0.1 < y < 0.3, and 0.2 < z < 0.6.

[0142] In some embodiments, the solid electrolyte material consists of a composition of Chemical Formula (VIII), Li 7- 3x+y-z B x La 3-y Ca y Zr 2-z Ta z O 12 ···(VIII) wherein B is Al, 0 ≤ x < 0.25, 0 < y ≤ 0.5, and 0 < z ≤ 1.

[0143] In some embodiments, 0 ≤ x < 0.15. In other embodiments, x is 0. Also, in some embodiments, x is 0 < x < 0.25. Also, in some embodiments, 0 < x < 0.15.

[0144] In some embodiments, 0 < y < 0.5. In other embodiments, 0 < y < 0.3.

[0145] In some embodiments, 0 < z < 1. In other embodiments, 0.2 < z < 0.6.

[0146] Unless otherwise specified, each subscript in any chemical formula shown in this specification means up to one hundredth digit, and the range of the subscript includes each one-hundredth value between the upper and lower limits of the range. For example, the range 0 < x < 1 includes 0.01, 0.02, ~0.98, and 0.99.

[0147] Unless otherwise specified, any component of any chemical formula described in this specification (e.g., D1, D2, D3, D4, B, C, D, and / or G) is a combination of different elements (e.g., Li, Na, and / or K), a combination of different types of cations (Li + , Na + , or K + ), or a combination of different types of anions (e.g., Cl - , Br - , and I - ). In such a case, the subscript (e.g., a, b, c, and / or d) immediately following such a component represents the total pfu of all elements, cation types, or anion types in the combination. Also, any component of any chemical formula described in this specification (e.g., D1, D2, D3, D4, B, C, D, and / or G) is a single element (e.g., Li, Na, or K), a single type of cation (Li + , Na + , or K + ), or a single type of anion (e.g., Cl - , Br - , or I - ). In such a case, the subscript (e.g., a, b, c, and / or d) immediately following such a component represents the total pfu of such an element, cation type, or anion type.

[0148] In some embodiments, the solid electrolyte material is sintered. In some embodiments, the sintered electrolyte material is incorporated into a ceramic separator. In some embodiments, the sintered electrolyte material is incorporated into a host structure for lithium metal plating and stripping. In some embodiments, the sintered electrolyte material physically contacts the cathode material and the anode material to form a combination of an electrode pair and a separator layer.

[0149] Another aspect of the present invention provides an electrode for a solid-state battery. The electrode includes a solid electrolyte material. The solid electrolyte material includes a composition of chemical formula (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII).

[0150] Another aspect of the present invention provides a two-layer solid electrolyte structure. The two-layer solid electrolyte structure includes a porous layer and a high-density layer. At least one of the porous layer and the high-density layer includes a solid electrolyte material composed of chemical formula (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII).

[0151] Another aspect of the present invention provides a three-layer solid electrolyte structure. The three-layer solid electrolyte structure includes a first porous layer, a high-density layer, and a second porous layer. At least one of the first porous layer, the high-density layer, and the second porous layer includes a solid electrolyte material composed of chemical formula (I), (II), (III), (IV), (V), (VI), (VII), and / or (VIII). In some embodiments, the high-density layer is disposed between the first porous layer and the second porous layer.

[0152] Another aspect of the present invention provides a solid-state battery including the solid electrolyte material described herein, the electrode described herein, the two-layer solid electrolyte structure described herein, or the three-layer solid electrolyte structure described herein.

[0153] III. Method for forming a green body In another aspect, the present invention provides a method for forming a green body. The method is (a) Reacting a precursor mixture to form a solid electrolyte material described herein; (b) Dispersing the solid electrolyte material in a solvent to form a dispersion material; (c) Mixing a first portion of the dispersion material with a first binder and a first plasticizer to form a high-density mixture; (d) Mixing a second portion of the dispersion material with a second binder, a second plasticizer, and a pore former to form a porous mixture; (e) Casting the high-density mixture onto a first substrate to form a high-density cast tape; (f) Casting the porous mixture onto a second substrate to form a porous cast tape; (g) Drying the high-density cast tape and the porous cast tape; (h) Laminating the high-density cast tape with the porous cast tape to form a green body.

[0154] In some embodiments, the method includes adding a lithium donor compound to at least one of the dispersion material, the high-density mixture, and the porous mixture. For example, the method may include adding a lithium donor compound to the dispersion material. In other embodiments, the method may include adding a lithium donor compound to the high-density mixture. And in some embodiments, the method may include adding a lithium donor compound to the porous mixture.

[0155] In some embodiments, step (a) of reacting includes firing the precursor mixture. For example, the firing may be performed in a heated crucible. In some embodiments, the crucible contains less than about 5 wt% Al2O3.

[0156] In some embodiments, the firing is performed at a temperature of about 600 °C to about 1,200 °C. In some embodiments, the firing is performed at a temperature of about 700 °C to about 1,100 °C. In some embodiments, the firing is performed at a temperature of about 800 °C to about 1,000 °C. Also, in some embodiments, the firing is performed at a temperature of about 900 °C.

[0157] In some embodiments, the firing is carried out for at least about 1 minute (e.g., from about 1 minute to about 60 minutes, from about 5 minutes to about 45 minutes, from about 10 minutes to about 45 minutes, from about 15 minutes to 30 minutes, from about 3 minutes to about 10 minutes, or from about 5 minutes to about 15 minutes). In other embodiments, the firing is carried out for at least about 1 hour (e.g., from about 1 hour to about 5 hours, from about 1.5 hours to about 4.5 hours, from about 2 hours to about 4 hours, or from about 2.5 hours to about 3.5 hours). In some embodiments, the firing is carried out for at least about 5 hours (e.g., from about 5 hours to about 12 hours, from about 6 hours to about 10 hours, or from about 6 hours to about 8 hours). In some embodiments, the firing is carried out over a period of from about 10 hours to about 14 hours.

[0158] In some embodiments, step (a) of reacting comprises (a-1) reacting a precursor mixture to form a solid electrolyte material; and (a-2) milling the solid electrolyte material to enhance uniformity and reduce particle size.

[0159] In some embodiments, step (a-2) of milling is carried out prior to dispersing the solid electrolyte material (i.e., step (b)).

[0160] In some embodiments, the method further comprises degassing at least one of the high-density mixture and the porous mixture under vacuum. For example, in some embodiments, the high-density mixture is degassed under vacuum. In other embodiments, the porous mixture is degassed under vacuum. Also, in some embodiments, both the high-density mixture and the porous mixture are degassed under vacuum.

[0161] In some embodiments, step (g) of drying is carried out at a temperature from about 20 °C to about 100 °C. In some embodiments, step (g) of drying is carried out at a temperature from about 40 °C to about 80 °C. In some embodiments, step (g) of drying is carried out at a temperature from about 50 °C to about 70 °C.

[0162] In some embodiments, the stacking step (h) comprises: (h-1) stacking a porous cast tape and a high-density cast tape; and (h-2) passing the stacked tapes through a heated roller press.

[0163] In some embodiments, the stacking step (h-1) may include stacking the porous cast tape on the high-density cast tape. In other embodiments, the stacking step (h-1) includes stacking the high-density cast tape on the porous cast tape. Also, in some embodiments, the method includes repeating the lamination step (h) to form a multi-layer green body.

[0164] In some embodiments, the heated roller press is heated to a temperature of about 50°C to about 500°C. In other embodiments, the heated roller press is heated to a temperature of about 100°C to about 300°C. Also, in some embodiments, the heated roller press is heated to a temperature of about 150°C to about 250°C.

[0165] Another aspect of the present invention provides a method for forming a sintered solid electrolyte. The method includes forming a green body according to any of the methods described herein. The method also includes sintering the green body to form a sintered solid electrolyte.

[0166] In some embodiments, the sintering step is performed at a temperature of about 1,200°C or less. For example, the sintering step can be performed at a temperature of about 900°C to about 1,200°C. In some embodiments, the sintering step is performed for about 1 minute to about 10 hours (e.g., about 1 minute to about 1 hour, about 3 minutes to about 15 minutes, about 5 minutes to about 30 minutes, about 30 minutes to about 60 minutes, about 1 hour to about 3 hours, or about 2 hours to about 4 hours). For example, the sintering step can be performed over about 1 minute to about 6 hours.

Examples

[0167] IV. Examples In order to enable a more complete understanding of the present invention described in this specification, the following examples are presented. The examples described in this application are provided to illustrate the methods and solid electrolyte materials provided in this specification and should in no way be construed as limiting their scope.

[0168] Solid electrolyte material Example 1: Solid Electrolyte Material of Chemical Formula (VI) A mixed raw material powder was prepared in a desired stoichiometric ratio to reach a multi-doped lithium lanthanum zirconium oxide (LLZO) of the chemical formula Li 7+y-z La 3-y Ca y Zr 2- z Ta z O 12 , where 0.1 < y < 0.3 and 0.2 < z < 0.6 (i.e., Chemical Formula (VI)). The precursor materials for this exemplary embodiment include lithium hydroxide monohydrate (98%, Alfa Aesar), lanthanum oxide (GFS Chemicals, 99.9%), zirconium(IV) oxide (Inframat Advanced Materials, 99.9%), calcium carbonate (Sigma Aldrich, 99.0%), and tantalum(V) oxide (MPIL, 99.9%). Ca 2+ was used to dope the La site, and Ta 5+ was used to dope the Zr site.

[0169] The mixed raw material powder was fired in a crucible at 900 °C for 12 hours (h) to form garnet powder. In this example, to prevent the migration of aluminum, the crucible was composed of less than 5 wt% Al2O3. Crucibles composed of MgO and / or Pt are suitable examples of such crucibles. The garnet powder was then ground in isopropanol to a uniform and small particle size and subsequently dried at 55 °C to remove the isopropanol. Next, the obtained prepared garnet powder was mixed with isopropanol and toluene as solvents and Z3 menhaden fish oil as a dispersant and ground overnight using milling media to create a dispersion. It will be understood that other grinding and dispersion methods may be used. Next, polyvinyl butyral (i.e., binder) and benzyl butyl phthalate (i.e., plasticizer) were added to the dispersion while mixing, and then the dispersion was degassed by mixing under vacuum. The degassed dispersion was then cast onto a biaxially stretched polyethylene terephthalate film (e.g., Mylar® film) using a doctor blade to form a cast tape (i.e., "high-density tape"). The cast tape was dried at 55 °C to form a green body of the solid electrolyte material. Another tape (i.e., "porous tape") was also molded in a similar manner except that a pore former was mixed during the addition of the binder and plasticizer. The tapes were stacked and the porous tape was laminated with the high-density tape by passing the tapes through a roller press heated to 200 °F (i.e., about 93.3 °C) to form a porous-high-density bilayer laminate. It will be understood that a multilayer laminate can be produced by laminating a plurality of high-density tapes and porous tapes at once or continuously. The obtained bilayer laminate was placed in a tubular furnace having a non-alumina surface without the mother powder in order to avoid the migration of aluminum to the product. Next, the bilayer laminate was sintered at 900 °C to 1200 °C for 1 minute (min) to 6 hours to form a sintered solid electrolyte material.

[0170] Example 2: Solid Electrolyte Material of Chemical Formula (VII) Chemical formula Li 7-3x+y-z Al x La 3-y Cay Zr 2-z Ta z O 12 That is, a solid electrolyte material composed of a composition where 0 < x < 0.15, 0.1 < y < 0.3, and 0.2 < z < 0.6 (i.e., the chemical formula (VII) described in this specification) was also prepared. The precursor materials for this exemplary embodiment included lithium hydroxide monohydrate (98%, Alfa Aesar), lanthanum oxide (GFS Chemicals, 99.9%), zirconium(IV) oxide (Inframat Advanced Materials, 99.9%), calcium carbonate (Sigma Aldrich, 99.0%), and tantalum(V) oxide (MPIL, 99.9%). Similar to the composition of Example 1, Ca 2+ was used to dope the La site, and Ta 5+ was used to dope the Zr site. Further, Al 3+ was used to dope the Li site. The composition of chemical formula (VII) and the resulting sintered solid electrolyte material were prepared in a substantially similar manner to the composition of chemical formula (VI) and its sintered solid electrolyte material in Example 1, except that Al 3+ (i.e., aluminum oxide) was introduced into the mixed powder before firing.

[0171] Analysis of Solid Electrolyte Materials Any solid electrolyte materials discussed in these examples other than those already described herein in Examples 1 and 2 were prepared in a substantially similar manner to the composition of chemical formula (VI) and its sintered solid electrolyte material shown in Example 1, except for the components used to form the underlying mixed raw material powder.

[0172] The sintered solid electrolyte materials were tested by means of a destructive test by manually bending them using a "4-point" bending configuration, followed by microscopic evaluation using a scanning electron microscope-backscattered electron detector (SEM-BSD) of the fracture sites and surfaces, which are evidence of porosity and secondary phases. It will be understood that a 3-point bending configuration can also be used.

[0173] Figures 1A - C show SEM - BSD images of sintered multi - doped LLZO (i.e., Li 6.55 Al 0.15 La3Zr2O 12 ) having Al doping exceeding about 0.15 pfu. Figure 1A shows a cross - section 101 of the sintered multi - doped LLZO. Figure 1B shows the LLZO surface 103 exposed during sintering. Figure 1C shows Al elemental mapping using SEM - energy - dispersive X - ray spectroscopy (EDS), showing an area 105 of concentrated Al in the same region as shown in Figure 1B. In each of these cases, it has been shown that lithium dendrites propagate along the Al - rich regions at the grain boundaries. Further, the non - uniformity of the crystal particle sizes in the cross - section shown in Figure 1C indicates abnormal crystal particle growth, which may be due to excessive incorporation of sintering aids. As a result, a significant secondary phase is formed at the grain boundaries, which is electrochemically reactive and may cause dendrite propagation. Further, these microstructures are also mechanically weak. Therefore, it is desirable to control the aluminum content to be less than about 0.24 pfu, or less than about 0.15 pfu and greater than 0.0 pfu.

[0174] In many cases, Al is introduced into the LLZO material during firing or sintering by using an alumina - rich crucible that is reactive to LLZO. When using a very high - purity alumina crucible during firing, for example, up to about 0.24 pfu or more of Al can be added to the LLZO. The amount of Al cannot be precisely controlled in this type of process. Instead, in some embodiments, the addition of a controlled amount of Al may be achieved by firing and / or sintering on a substrate containing less than about 5% Al2O3 using a desired amount of an Al - containing precursor material before firing.

[0175] Figures 2A and B show the effect of less than about 0.15 pfu of Al on the microstructure of sintered multi-doped LLZO with and without Al. In Figure 2A, the LLZO bilayer was sintered without Al doping. The cross-section of the high-density layer 201 under the porous layer 203 can be seen in Figure 2A to have a granular and low-density structure after sintering. In contrast, Figure 2B shows the cross-section of the Al-doped LLZO high-density layer 205 under the porous layer 207, with improved density with significantly less grain formation. The presence of less than about 0.15 pfu (e.g., less than about 0.12 pfu, less than about 0.10 pfu, or from about 0.01 pfu to about 0.08 pfu) of Al significantly improves the density and reduces the porosity of the sintered LLZO without forming unstable secondary phases. In the solid electrolyte of Figure 2B, aluminum is present in an amount of 0.05 pfu.

[0176] Figure 3 shows the SEM-BSD cross-section of sintered multi-doped LLZO having a bilayer configuration of a porous layer 301 and a high-density layer 303, where the LLZO is doped with less than about 0.1 pfu of Al, less than about 0.3 pfu and more than about 0.1 pfu of Ca, and more than about 0.4 pfu and less than about 0.6 pfu of Ta. Advantageously, the sintered multi-doped LLZO of Figure 3 was prepared without using a powder bed.

[0177] Figures 4A and B are images of the cross-sections of the sintered multi-doped LLZO of Examples 1 and 2. Both sintered multi-doped LLZO materials were prepared without using a powder bed. In Figure 4A, the sintered multi-doped LLZO of Example 1 having a porous layer 401 and a high-density layer 403 is shown. As can be seen from the figure, the high-density layer 403 is significantly porous. Importantly, when lithium is lost during sintering resulting in a lithium deficiency in the LLZO composition, the LLZO cannot be properly sintered to densify. Lithium deficiency can occur when the lithium present is less than the stoichiometric amount and / or when the lithium loss hinders the formation of a stable cubic phase during firing and / or sintering. Generally, a loss of more than about 1% of lithium from the initial amount can lead to lithium deficiency.

[0178] Figure 4B shows the sintered multi-doped LLZO of Example 2 having a porous layer 405 and a high-density layer 407. As can be seen from the figure, the high-density layer 407 has a very low porosity and is completely sintered without using a powder bed. The ability to effectively sinter without using a powder bed demonstrates a potential advantage of the solid electrolyte materials described herein.

[0179] Conductivity of the solid electrolyte material The sintered solid electrolyte materials of Examples 1 and 2 were tested for conductivity. Au electrodes were sputtered on both sides of each sintered solid electrolyte material. Ag paste was used to bond the contacts of the Ag wires. Electrochemical impedance spectroscopy was used to analyze the impedance response of the sintered solid electrolyte materials over a frequency range of 1 MHz to 100 Hz to determine the ionic conductivity. The ionic conductivity of the sintered solid electrolyte of Example 1 was measured to be 2.2 mS / cm. The sintered solid electrolyte material of Example 2 exhibited an ionic conductivity of 4.2 mS / cm.

[0180] X-ray diffraction analysis Compositions such as those described herein can be quality-checked after mixing and firing processes, for example, by inductively coupled plasma, X-ray diffraction (XRD), and thermogravimetric loss. Preferably, the powder obtained after firing has a uniform composition, has the desired crystalline phase purity as determined by XRD, has very little of the remaining unreacted components such as hydroxides and carbonates (evaluated by measuring the thermogravimetric loss), and has the desired elemental composition as determined by inductively coupled plasma.

[0181] Figure 5 shows the reference XRD spectra of cubic LLZO 507 and tetragonal LLZ 505, as well as the measurement results of as-fired multi-doped LLZO 503 (i.e., the fired composition of Example 2) and as-fired undoped LLZ 501. The multi-doped and undoped LLZO were mixed and fired as described above. As shown in Figure 5, the multi-doped LLZO 503 has a high Li +It well matches the cubic phase 507 of the conductivity, but the undoped LLZO 501 matches the tetragonal phase 505 with low conductivity.

[0182] Battery cell In some embodiments of the present approach, the sintered electrolyte may be incorporated into the battery cell as a ceramic separator, or as a host structure for lithium metal plating, or both. The sintered electrolyte physically contacts the cathode material and the anode material to form a combination of the electrode pair and the separator layer of the battery. These layers may optionally be stacked with an anode current collector that contacts the anode surface on the opposite side of the solid electrolyte separator and a cathode current collector that contacts the anode surface on the opposite side of the solid electrolyte separator to form a cell. This battery cell can be incorporated into a wide variety of applications including, but not limited to, electric vehicles.

[0183] A battery cell including the multi-doped LLZO ceramic bilayer separator according to Example 2 was fabricated using an anode (lithium metal) and a cathode (lithium nickel manganese cobalt oxide (NMC)). Figure 6 shows the voltage profile of the battery cell as a function of capacity when the cell is charged and discharged at C / 20 (first cycle), C / 10 (second to third cycles), and C / 5 (fourth to seventh cycles). The high coulombic efficiency indicates high cell performance, as is evident from the very similar charge and discharge capacities for each cycle.

[0184] Equivalents and ranges In the claims, articles such as "a", "an", and "the" can mean one or more unless the contrary is indicated or is otherwise clear from the context. A claim or description that includes "or" between one or more elements of a group, unless the contrary is indicated or is otherwise clear from the context, is considered satisfied if one, two or more, or all of the elements of the group are present in, used in, or otherwise relevant to a given product or process. The invention includes embodiments in which exactly one element of the group is present in, used in, or otherwise relevant to a given product or process. The invention includes embodiments in which two or more or all of the elements of the group are present in, used in, or otherwise relevant to a given product or process.

[0185] Furthermore, the present invention encompasses all variations, combinations, and permutations in which one or more limitations, elements, clauses, and descriptive terms from one or more of the recited claims are introduced into another claim. For example, any claim that depends on another claim can be modified to include one or more limitations found in any other claim that depends on the same basic claim. If elements are presented as a list, for example, in Markush group form, each subgroup of the elements is also disclosed, and any element(s) can be removed from this group. In general, when the present invention, or an aspect of the present invention, is said to include a particular element and / or feature, it should be understood that a particular embodiment of the present invention or an aspect of the present invention consists of or consists essentially of such element and / or feature. For the sake of brevity, those embodiments are not specifically recited verbatim herein. It should also be noted that the terms "comprising" and "including" are intended to be open and allow the inclusion of additional elements or steps. When a range is given, the endpoints are included. Furthermore, unless otherwise indicated or otherwise apparent from the context and the understanding of one of ordinary skill in the art, values expressed as ranges can be assumed to be within the defined range of the lower limit of the unit of one-tenth to any specific value or sub-range within the defined range of different embodiments of the present invention, unless the context clearly dictates otherwise.

[0186] This application refers to various issued patents, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference. In case of any conflict between any of the incorporated references and this specification, this specification shall prevail. Moreover, any particular embodiment of the present invention within the prior art can be clearly excluded from one or more of the claims. Such embodiments are considered to be known to one of ordinary skill in the art and can be excluded even if the exclusion is not explicitly stated herein. Any particular embodiment of the present invention can be excluded from any claim for any reason, regardless of whether it is related to the existence of the prior art.

[0187] One of ordinary skill in the art will recognize, or be able to ascertain, many equivalents to the specific embodiments described herein using only routine experimentation. The scope of the embodiments described in this invention is not intended to be limited to the above description, but rather is as set forth in the appended claims. As defined in the following claims, it will be apparent to one of ordinary skill in the art that various changes and modifications to this description can be made without departing from the spirit or scope of the invention.

Claims

1. A solid electrolyte material comprising a composition of formula (I), M1 ７－ｘ D1 ａ M2 ３－ｙ D2 ｂ M3 ２－ｚ D3 ｃ O １２－ｗ D4 ｄ ... (I) wherein, M1 is Li, M2 is La, M3 is Zr, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, N, P, or any combination thereof, 0 ≦ w ≦ 2, -0.5 < x ≦ 3, 0 ≦ y ≦ 3, 0 ≦ z ≦ 2, 0 ≦ a ≦ 2, 0 ≦ b ≦ 3, 0 ≦ c ≦ 2, and 0 ≦ d ≦ 2, and wherein at least one of a, b, c, and d is not 0, said solid electrolyte material.

2. 0 < y ≦ 3, 0 < z ≦ 2, 0 < a ≦ 2, 0 < b ≦ 3, and 0 < c ≦ 2, the solid electrolyte material according to Claim 1.

3. 0 ≦ w ≦ 1, the solid electrolyte material according to Claim 1 or 2.

4. 0 ≦ w ≦ 0.5, the solid electrolyte material according to any one of Claims 1 to 3.

5. 0 ≦ w ≦ 0.1, the solid electrolyte material according to any one of Claims 1 to 4.

6. 0 ≦ x ≦ 1, the solid electrolyte material according to any one of Claims 1 to 5.

7. 0.2 ≦ x ≦ 0.8, the solid electrolyte material according to any one of Claims 1 to 6.

8. 0 < y < 3, the solid electrolyte material according to any one of Claims 1 to 7.

9. 0 < y < 1, the solid electrolyte material according to any one of Claims 1 to 8.

10. 0 < y < 0.5, the solid electrolyte material according to any one of Claims 1 to 9.

11. 0.05 ≦ y ≦ 0.25, the solid electrolyte material according to any one of Claims 1 to 10.

12. 0 < a ≦ 1, the solid electrolyte material according to any one of Claims 1 to 11.

13. 0 < a < 0.24, the solid electrolyte material according to any one of Claims 1 to 12.

14. The solid electrolyte material according to any one of claims 1 to 13, wherein 0 < b < 3.

15. The solid electrolyte material according to any one of claims 1 to 14, wherein 0 < b < 1.

16. The solid electrolyte material according to any one of claims 1 to 15, wherein 0 < b < 0.

5.

17. The solid electrolyte material according to any one of claims 1 to 16, wherein 0.05 ≤ b ≤ 0.

25.

18. The solid electrolyte material according to any one of claims 1 to 17, wherein 0 < c ≤ 0.

7.

19. The solid electrolyte material according to any one of claims 1 to 18, wherein 0 < c ≤ 0.

5.

20. The solid electrolyte material according to any one of claims 1 to 19, wherein 0.2 ≤ c ≤ 0.

5.

21. The solid electrolyte material according to any one of claims 1 to 20, wherein 0 ≤ d ≤ 1.

22. The solid electrolyte material according to any one of claims 1 to 21, wherein 0 ≤ d ≤ 0.

5.

23. The solid electrolyte material according to any one of claims 1 to 22, wherein 0 ≤ d ≤ 0.

1.

24. The solid electrolyte material according to any one of claims 1 to 23, wherein D1 is Al, Fe, Zn, and Ga, or any combination thereof.

25. The solid electrolyte material according to any one of claims 1 to 24, wherein D2 is Ca, Sr, Ba, Bi, and Nd, or any combination thereof.

26. The solid electrolyte material according to any one of claims 1 to 25, wherein D3 is Ta, Nb, W, Ti, and Mo, or any combination thereof.

27. 7 - x = 7 - a(vD1) + b(3 - vD2) + c(4 - vD4) - d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d, for the solid electrolyte material according to claim 1.

28. The solid electrolyte material according to claim 27, wherein 0 ≤ x ≤ 1.

0.

29. A solid electrolyte material comprising a composition of formula (II), Li ７－ｘ D1 ａ La ３－ｙ D2 ｂ Zr ２－ｚ D3 ｃ O １２－ｗ D4 ｄ ・・・(II) wherein, D1 is H, Be, B, Al, Fe, Zn, Ga, Ge, or any combination thereof, D2 is Na, K, Ca, Rb, Sr, Y, Ag, Ba, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Zn, Ce, or any combination thereof, D3 is Mg, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Ce, Eu, Te, Y, Sr, Ca, Ba, Gd, Ge, or any combination thereof, D4 is F, Cl, Br, I, S, Se, Te, or any combination thereof, 0 ≦ w < 2, -0.5 < x ≦ 3, 0 < y ≦ 3, 0 < z ≦ 2, 0 < a ≦ 2, 0 < b ≦ 3, 0 < c ≦ 2, and 0 ≦ d ≦ 2, and the solid electrolyte material.

30. The solid electrolyte material according to claim 29, wherein 0 ≦ w ≦ 1.

31. The solid electrolyte material according to claim 29 or 30, wherein 0 ≦ w ≦ 0.

5.

32. The solid electrolyte material according to any one of claims 29 to 31, wherein 0 ≦ w ≦ 0.

1.

33. The solid electrolyte material according to any one of claims 29 to 32, wherein 0 < x ≦ 1.

5.

34. The solid electrolyte material according to any one of claims 29 to 33, wherein 0.5 < y ≦ 2.

35. The solid electrolyte material according to any one of claims 29 to 34, wherein 0.5 < z ≦ 1.

5.

36. The solid electrolyte material according to any one of claims 29 to 35, wherein 0 < a < 0.

24.

37. The solid electrolyte material according to any one of claims 29 to 36, wherein 0 < b ≦ 2.

38. The solid electrolyte material according to any one of claims 29 to 37, wherein 0 < c ≦ 1.

5.

39. The solid electrolyte material according to any one of claims 29 to 38, wherein 0 ≦ d ≦ 1.

40. The solid electrolyte material according to any one of claims 29 to 39, wherein 0 ≦ d ≦ 0.

5.

41. The solid electrolyte material according to any one of claims 29 to 40, wherein 0 ≦ d ≦ 0.

1.

42. D1 is Al, Ga, or any combination thereof, D2 is Ca, Sr, Ba, or any combination thereof, 0 < b ≦ 0.5, D3 is Ta, Nb, W, Ti, Mo, or any combination thereof, 0 < c ≦ 1.0, The solid electrolyte material according to claim 29, wherein D4 is F, Cl, or any combination thereof.

43. The solid electrolyte material according to claim 42, wherein 0 < a ≦ 0.

25.

44. The solid electrolyte material according to claim 42 or 43, wherein 0 < b ≤ 0.

5.

45. The solid electrolyte material according to any one of claims 42 to 44, wherein 0 < c ≤ 1.

0.

46. The solid electrolyte material according to any one of claims 42 to 45, wherein 0 ≤ d ≤ 0.

25.

47. The solid electrolyte material according to any one of claims 42 to 46, wherein 0 ≤ x ≤ 1.

0.

48. The solid electrolyte material according to any one of claims 42 to 47, wherein 0 ≤ y ≤ 0.

5.

49. The solid electrolyte material according to any one of claims 42 to 48, wherein 0 ≤ z ≤ 1.

0.

50. The solid electrolyte material according to any one of claims 42 to 49, wherein 0 ≤ w ≤ 0.

25.

51. 7 - x = 7 - a(vD1) + b(3 - vD2) + c(4 - vD4) - d / 2, where vD1 is the oxidation state of D1, vD2 is the oxidation state of D2, vD3 is the oxidation state of D3, D4 is F, Cl, Br, I, or any combination thereof, y = b, z = c, and w = d. The solid electrolyte material according to claim 29.

52. The solid electrolyte material according to claim 51, wherein 0 ≤ x ≤ 1.

0.

53. A solid electrolyte material comprising a composition of chemical formula (IV), Li ｎ B ｘ ｖＢ La ３－ｙ C ｙ ｖＣ Zr ２－ｚ D ｚ ｖＤ O １２－ａ G ａ ・・・(IV) wherein, n = 7 - x(vB) + y(3 - vC) + z(4 - vD) - a / 2, where vB is the oxidation state of B, vC is the oxidation state of C, vD is the oxidation state of D, B is H ＋ , Al ３＋ , Ga ３＋ , Fe ３＋ , Zn ２＋ , Ge ４＋ , or any combination thereof, C is Ca ２＋ , Ba ２＋ , Sr ２＋ , Mg ２＋ , Rb ＋ , Ce ４＋ , or any combination thereof, D is Ta ５＋ , Y ３＋ , Mo ６＋ , Nb ５＋ , W ６＋ , Ge ４＋ , Ti ４＋ , or any combination thereof, G is F － , Cl － , Br － , I － , or any combination thereof, 0 < x < 0.24, 0 < y ≤ 1.0, 0 < z ≤ 1.0, and 0 ≤ a ≤ 1.

0. The solid electrolyte material.

54. B is Al ３＋ The solid electrolyte material according to claim 53, wherein B is Al.

55. C is Ca ２＋ The solid electrolyte material according to claim 53 or 54, wherein C is Ca.

56. D is Ta ５＋ , Nb ５＋ , Ti ４＋ or any combination thereof, the solid electrolyte material according to any one of claims 53 to 55.

57. D is Ta ５＋ The solid electrolyte material according to any one of claims 53 to 56, wherein D is Ta.

58. The solid electrolyte material according to any one of claims 53 to 57, wherein 0 < x < 0.15, and at least one of 0 < x < 0.15, 0 < y < 0.50, and 0 < z < 0.

70.

59. The solid electrolyte material according to any one of claims 53 to 58, wherein 0.02 < x < 0.

10.

60. The solid electrolyte material according to any one of claims 53 to 59, wherein 0 < y < 0.

50.

61. The solid electrolyte material according to any one of claims 53 to 60, wherein 0.1 < y < 0.

30.

62. The solid electrolyte material according to any one of claims 53 to 61, wherein 0.15 < y < 0.

28.

63. The solid electrolyte material according to any one of claims 53 to 62, wherein 0 < z < 0.

70.

64. The solid electrolyte material according to any one of claims 53 to 63, wherein 0.3 < z < 0.

6.

65. The solid electrolyte material according to any one of claims 53 to 64, wherein 0.4 < z < 0.

55.

66. The solid electrolyte material according to any one of claims 53 to 65, wherein 0 ≦ a < 0.

1.

67. The solid electrolyte material according to any one of claims 53 to 66, wherein 0 ≦ a < 0.

05.

68. The solid electrolyte material according to claim 53, wherein x, y, z, and a are selected such that 6 ≦ n ≦ 7.

69. A solid electrolyte material comprising a composition of chemical formula (V), Li ７－ｘ B ａ La ３－ｙ C ｂ Zr ２－ｚ D ｃ O １２ ... (V) wherein B is Al or Ga, C is Ca, Sr, Ba, or Mg, D is Ta, Nb, W, Mo, or Ti, 0 ≦ x ≦ 1, 0 < a < 0.24, 0 < y ≦ 0.5, 0 < b ≦ 0.5, 0 < z ≦ 1, and 0 < c ≦ 1, said solid electrolyte material.

70. A solid electrolyte material comprising a composition of chemical formula (VI), Li ７＋ｙ－ｚ La ３－ｙ Ca ｙ Zr ２－ｚ Ta ｚ O １２ ... (VI) wherein 0 < y < 0.3, and 0.2 < z < 0.6, said solid electrolyte material.

71. A solid electrolyte material comprising a composition of chemical formula (VII), Li ７－３ｘ＋ｙ－ｚ Al ｘ La ３－ｙ Ca ｙ Zr ２－ｚ Ta ｚ O １２ ・・・(VII) wherein 0 < x < 0.15, 0 < y < 0.3, and 0.2 < z < 0.6, said solid electrolyte material.

72. A solid electrolyte material comprising a composition of chemical formula (VIII), Li ７－３ｘ＋ｙ－ｚ B ｘ La ３－ｙ Ca ｙ Zr ２－ｚ Ta ｚ O １２ ・・・(VIII) wherein B is Al, 0 ≦ x < 0.25, 0 < y ≦ 0.5, and 0 < z ≦ 1, said solid electrolyte material.

73. The solid electrolyte material according to claim 72, wherein 0 ≦ x < 0.

15.

74. The solid electrolyte material according to claim 72, wherein x is 0.

75. The solid electrolyte material according to claim 72, wherein 0 < x < 0.

25.

76. The solid electrolyte material according to claim 72, wherein 0 < y < 0.

3.

77. The solid electrolyte material according to claim 72, wherein 0.2 < z < 0.

6.

78. A two-layer solid electrolyte structure comprising a porous layer and a high-density layer, wherein at least one of said porous layer and said high-density layer comprises the solid electrolyte material according to any one of claims 1 to 77, said two-layer solid electrolyte structure.

79. A three-layer solid electrolyte structure comprising a first porous layer, a high-density layer, and a second porous layer, The three-layer solid electrolyte structure, wherein at least one of the first porous layer, the high-density layer, and the second porous layer contains the solid electrolyte material according to any one of claims 1 to 77.

80. The solid electrolyte material according to any one of claims 1 to 77, wherein the solid electrolyte material is sintered.

81. A solid battery including the electrolyte material according to any one of claims 1 to 77.

82. The solid battery according to claim 81, wherein the electrolyte material is sintered.

83. The solid battery according to claim 82, wherein the sintered electrolyte material is incorporated into a ceramic separator.

84. The solid battery according to claim 82, wherein the sintered electrolyte material is incorporated into a host structure for lithium metal plating and stripping.

85. The solid battery according to claim 82, wherein the sintered electrolyte material physically contacts a cathode material and an anode material to form a combination of an electrode pair and a separator layer.

86. A method for forming a green body, comprising: (a) reacting a precursor mixture to form the solid electrolyte material according to any one of claims 1 to 77; (b) dispersing the solid electrolyte material in a solvent to form a dispersion material; (c) mixing a first portion of the dispersion material with a first binder and a first plasticizer to form a high-density mixture; (d) mixing a second portion of the dispersion material with a second binder, a second plasticizer, and a pore former to form a porous mixture; (e) casting the high-density mixture onto a first substrate to form a high-density cast tape; (f) casting the porous mixture onto a second substrate to form a porous cast tape; (g) drying the high-density cast tape and the porous cast tape; (h) laminating the porous cast tape onto the high-density cast tape to form a green body.

87. The method according to claim 86, further comprising adding a lithium donor compound to at least one of the dispersion material, the high-density mixture, and the porous mixture.

88. The method according to claim 86, wherein the step (a) of reacting includes firing the precursor mixture.

89. The method according to claim 88, wherein the firing is performed in a heated crucible.

90. The step (a) of reacting is (a-1) Reacting a precursor mixture to form a solid electrolyte material; (a-2) Pulverizing the solid electrolyte material to enhance uniformity and reduce the particle size, the method according to claim 86, comprising. (Claim 91) (Claim 86) The method further comprising degassing at least one of the high-density mixture and the porous mixture under vacuum. (Claim 92) (h) The step of laminating is (h-1) Stacking the porous cast tape and the high-density cast tape; (h-2) Passing the stacked tape through a heated roller press, the method according to claim 86, comprising. (Claim 93) (Claim 86) The method, wherein the step of laminating is repeated to form a multilayer green body. (Claim 94) (Claim 86) A method for forming a sintered solid electrolyte, comprising: (Claim 86) Forming a green body according to the method according to any one of claims 86 to 93; (Claim 86) Sintering the green body to form the sintered solid electrolyte, the method.

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