CN117794863A

CN117794863A - Lithium Lanthanum Zirconium Oxide (LLZO) material

Info

Publication number: CN117794863A
Application number: CN202280053017.6A
Authority: CN
Inventors: R·K·霍尔曼; G·M·罗贝尔
Original assignee: 6k Co ltd
Current assignee: 6k Co ltd
Priority date: 2021-07-30
Filing date: 2022-07-21
Publication date: 2024-03-29

Abstract

Disclosed herein are materials and methods for producing lithium oxide materials, such as Lithium Lanthanum Zirconium Oxide (LLZO), having small particle sizes and high densities for lithium ion batteries. Some embodiments relate to formation in the presence of hydrogen at a temperature below the melting point of lithium carbonate andpost-heating comprises lithium carbonate and La ₂ Zr ₂ O ₇ Such that at least a portion of the lithium carbonate decomposes to form lithium oxide. In some embodiments, the lithium oxide is heated to a temperature sufficient to crystallize the lithium oxide to form a solid electrolyte material comprising Lithium Lanthanum Zirconium Oxide (LLZO) particles.

Description

Lithium Lanthanum Zirconium Oxide (LLZO) material

Incorporation by reference of any priority application

The present application claims priority from U.S. c. ≡119 (e) U.S. provisional application No. 63/203,810 filed on day 2021, month 7, and provisional application No. 63/273,833 filed on day 2021, month 10, and 29, the entire disclosure of each of which is incorporated herein by reference.

Background

Technical Field

The present disclosure, in some embodiments, relates generally to the manufacture of lithium oxides, including doped and undoped Lithium Lanthanum Zirconium Oxide (LLZO) materials, and methods of manufacture.

Background

In lithium ion batteries, lithium cobalt oxide is conventionally used as the cathode material. However, many alternative material systems have also been developed and used. Typically, lithium and oxygen are an essential part of the material system. Cobalt may often be completely or partially replaced by other metallic elements, such as nickel and manganese. For this reason, most lithium ion batteries can be described as lithium metal oxide batteries.

Lithium metal oxides are prepared as solid powders. The microstructure, morphology, particle size and the degree and type of possible contamination in the powder play a decisive role in the selection of the powder as a suitable material for use as cathode in lithium ion batteries. These properties affect the electrochemical characteristics of the cell. In particular, the energy density is very important. For example, the energy density may affect the distance an electric vehicle can travel and is affected by the microstructure parameters described above.

Therefore, the microstructure of the lithium metal oxide material must be precisely adjusted. The lithium metal oxide is lithium oxideMixed crystals of oxides of other metals. Conventionally, these mixed crystals are formed by heat treating a mixture of the respective oxides at a high temperature (typically between 800 and 1000 ℃) under certain atmospheric conditions. Each oxide is in turn provided by adding various raw materials to the mixture. The starting materials are generally hydroxides or carbonates of lithium and other respective metal elements. By heat-treating these starting materials, water is released at high temperature (H ₂ O) or carbon dioxide (CO) ₂ ). The remaining oxide participates later in the mixed crystal by further processing. In general, in the manufacturing process of materials, various oxides are extracted from respective hydroxides or carbonates of the same element in a first step, and then, in a second step, desired mixed crystals are produced from these oxides.

The first step is called calcination, in which the two solids react together to form a third solid, and the gas is released. The second step is called sintering or solid diffusion. Calcination occurs almost time-independent once the temperature required for the reaction to begin and the starting materials are available. However, calcination is typically carried out at high temperatures, resulting in an undesirable increase in material particle size during this process. Furthermore, it is difficult to obtain a lithium oxide material for a dense film due to the influence of gas generated in the process.

Thus, new methods for producing lithium oxide materials having small particle sizes and high densities are needed.

Disclosure of Invention

Some embodiments herein relate to a method for producing a solid electrolyte material, the method comprising: heating a multiphase material comprising lithium carbonate in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide; and heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form a solid electrolyte material comprising Lithium Lanthanum Zirconium Oxide (LLZO) particles.

In some embodiments, the average particle size of the multiphase material is between about 20nm and about 1000 nm. In some embodiments, the average particle size of the multiphase material is about 300nm.

In some embodiments of the present invention, in some embodiments,the multiphase material further comprises lanthanum (La). In some embodiments, the multiphase material further comprises zirconium (Zr). In some embodiments, the multiphase material further comprises lanthanum (La) and zirconium (Zr). In some embodiments, the multiphase material further comprises lanthanum zirconium oxide. In some embodiments, the multiphase material further comprises La ₂ Zr ₂ O ₇ 。

In some embodiments, the LLZO further comprises one or more dopants. In some embodiments, the one or more dopants include at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), or boron (B). In some embodiments, the LLZO further comprises LaAlO ₃ Or La (La) ₂ (Li _0.5 Al _0.5 )O ₄ At least one of them.

In some embodiments, the multiphase material further comprises lialalao ₂ 、Li ₂ ZrO ₃ 、ZrO ₂ 、LaAlO ₃ 、Li ₂ Zr ₂ O ₇ 、La ₂ O ₃ 、La ₂ (Li _0.5 Al _0.5 )O ₄ 、LiLaO ₂ 、Li ₅ AlO ₄ 、La ₂ O ₂ CO ₃ Or Li (lithium) _a Zr _b O _c At least one of which is 1.ltoreq.a.ltoreq.8, 1.ltoreq.b.ltoreq.2, and 1.ltoreq.c.ltoreq.7.

In some embodiments, the solid electrolyte material further comprises one or more dopants. In some embodiments, the one or more dopants include at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), or boron (B).

In some embodiments, the solid electrolyte material has an average particle size between about 20nm and about 1000 nm. In some embodiments, the solid electrolyte material has an average particle size of about 300nm.

In some embodiments, the portion of the lithium carbonate that decomposes to form lithium oxide is at least 50% by weight of the lithium carbonate in the multiphase material. In some embodiments, the portion of the lithium carbonate that decomposes to form lithium oxide is at least 75% by weight of the lithium carbonate in the multiphase material. In some embodiments, the portion of the lithium carbonate that decomposes to form lithium oxide is at least 90% by weight of the lithium carbonate in the multiphase material. In some embodiments, the portion of the lithium carbonate that decomposes to form lithium oxide is at least 99% by weight of the lithium carbonate in the multiphase material.

In some embodiments, the total time of heating of the multiphase material and heating of the lithium oxide is between about 2 hours and about 20 hours. In some embodiments, the multiphase material is heated for between about 1 hour and about 10 hours. In some embodiments, the lithium oxide is heated for between about 1 hour and about 10 hours.

In some embodiments, the method further comprises forming the thin film from a solid electrolyte material.

In some embodiments, at least a portion of the lithium carbonate forms a lithium peroxide upon heating the multiphase material. In some embodiments, the lithium oxide is heated at a temperature greater than 600 ℃. In some embodiments, the lithium oxide is heated to a temperature above 640 ℃. In some embodiments, the lithium oxide is heated in an oxygen-containing atmosphere. In some embodiments, the lithium oxide is heated in the absence of hydrogen. In some embodiments, the amount of lithium loss that occurs during the process is less than 3% by weight.

In some embodiments, the method further comprises forming the multiphase material with a microwave plasma process, the method comprising: inputting one or more feedstock materials into a microwave-generated plasma to form a multiphase material; and collecting the multiphase material.

Some embodiments herein relate to a method for producing Lithium Lanthanum Zirconium Oxide (LLZO) particles, the method comprising: heating a mixture comprising lithium carbonate and La in the presence of hydrogen at a temperature below the melting point of lithium carbonate ₂ Zr ₂ O ₇ Such that at least a portion of the lithium carbonate decomposes to form lithium oxide; and heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

In some embodiments, the LLZO further comprises one or more dopants. In some embodiments, the one or more dopants include at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), and boron (B). In some embodiments, the LLZO further comprises LaAlO ₃ Or La (La) ₂ (Li _0.5 Al _0.5 )O ₄ At least one of them.

In some embodiments, the multiphase material further comprises lialalao ₂ 、Li ₂ ZrO ₃ 、ZrO ₂ 、LaAlO ₃ 、La ₂ O ₃ 、La ₂ (Li _0.5 Al _0.5 )O ₄ 、LiLaO ₂ 、Li ₅ AlO ₄ 、La ₂ O ₂ CO ₃ Or Li (lithium) _a Zr _b O _c At least one of which is 1.ltoreq.a.ltoreq.8, 1.ltoreq.b.ltoreq.2, and 1.ltoreq.c.ltoreq.7.

In some embodiments, the average particle size of the LLZO is between about 20nm and about 1000 nm. In some embodiments, the average particle size of the LLZO is about 300nm.

In some embodiments, the method further comprises forming a film from the LLZO particles. In some embodiments, at least a portion of the lithium carbonate forms a lithium peroxide upon heating the multiphase material.

In some embodiments, the lithium oxide is heated at a temperature greater than 600 ℃. In some embodiments, the lithium oxide is heated to a temperature above 640 ℃. In some embodiments, the lithium oxide is heated in an oxygen-containing atmosphere. In some embodiments, the lithium oxide is heated in the absence of hydrogen. In some embodiments, the amount of lithium loss that occurs during the process is less than 3% by weight.

Some embodiments herein relate to a method for producing a multiphase material, the method comprising: preparing a feedstock comprising lanthanum and zirconium; introducing a feedstock into a microwave plasma torch, a plasma plume of the microwave plasma torch, and/or an exhaust of the microwave plasma torch; and heating the microwave plasma torch, the plasma plume of the microwave plasma torch, and/or the feedstock within the exhaust of the microwave plasma torch to form a multiphase material comprising lithium carbonate and lanthanum zirconate.

In some embodiments, the multiphase material further comprises at least one of lanthanum aluminate, lithium aluminum oxide, and lanthanum oxide carbonate. In some embodiments, the multiphase material includes phases of lithium carbonate and lanthanum zirconate within individual particles of the multiphase material.

In some embodiments, the method further comprises heating the multiphase material in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide. In some embodiments, the method further comprises heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

Some embodiments herein relate to a multiphase material that includes lithium carbonate and lanthanum zirconate within individual particles of the multiphase material.

In some embodiments, the multiphase material is formed by a process comprising: preparing a feedstock comprising lanthanum and zirconium; introducing a feedstock into a microwave plasma torch, a plasma plume of the microwave plasma torch, and/or an exhaust of the microwave plasma torch; and heating the microwave plasma torch, the plasma plume of the microwave plasma torch, and/or the feedstock within the exhaust of the microwave plasma torch to form a multiphase material. In some embodiments, the method further comprises heating the multiphase material in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide. In some embodiments, the method further comprises heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

In some embodiments, the multiphase material further comprises at least one of lanthanum aluminate, lithium aluminum oxide, and lanthanum oxide carbonate. In some embodiments, the multiphase material includes phases of lithium carbonate and lanthanum zirconate within individual particles of the multiphase material. Some embodiments herein relate to a Lithium Lanthanum Zirconium Oxide (LLZO) material formed by a method comprising: heating a mixture comprising lithium carbonate and La in the presence of hydrogen at a temperature below the melting point of lithium carbonate ₂ Zr ₂ O ₇ Such that at least a portion of the lithium carbonate decomposes to form lithium oxide; and heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

Drawings

The drawings are provided to illustrate example embodiments and are not intended to limit the scope of the disclosure. The systems and methods described herein will be better understood with reference to the following description in conjunction with the accompanying drawings, in which:

fig. 1 illustrates an exemplary microwave plasma torch that may be used to produce materials according to some embodiments of the present disclosure.

Fig. 2A-B illustrate an exemplary microwave plasma torch including a side feed hopper.

Fig. 3A is an electron micrograph of a multiphase starting material produced by a microwave plasma process according to some embodiments described herein.

Fig. 3B is a phase identification of a multi-phase starting material produced by a microwave plasma process via X-ray diffraction according to some embodiments described herein.

Fig. 4A-B are electron micrographs of LLZO materials calcined in the presence of hydrogen according to some embodiments described herein.

Fig. 4C is a phase identification of LLZO materials calcined in the presence of hydrogen via x-ray diffraction according to some embodiments described herein.

Fig. 5A-B are electron micrographs of LLZO materials calcined in the presence of hydrogen and oxygen according to some embodiments described herein.

Fig. 5C is a phase identification of LLZO materials calcined in the presence of hydrogen and oxygen via x-ray diffraction according to some embodiments described herein.

Fig. 6 illustrates a table summarizing the stoichiometric properties, particle size, and phase of LLZO materials according to some embodiments herein.

Detailed Description

Although certain preferred embodiments and examples are disclosed below, the inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and modifications and equivalents thereof. Therefore, the scope of the appended claims is not to be limited by any of the specific embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable order and are not necessarily limited to any particular disclosed order. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed as to imply that these operations are order dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or separate components. In order to compare various embodiments, certain aspects and advantages of these embodiments are described. Not all such aspects or advantages may be realized by any particular embodiment. Thus, for example, various embodiments may be performed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may be taught or suggested herein.

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will recognize that the devices and methods illustrated in the specific description and drawings herein are non-limiting exemplary embodiments and that the scope of the invention is limited only by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present technique.

One promising class of ion-conducting ceramics for solid state battery cells is based on Lithium Lanthanum Zirconium Oxide (LLZO). These materials have up to 10 ^-3 S/cm, and has excellent electrochemical stability. Embodiments of the present disclosure may be incorporated into solid state batteries, for example, in separators, electrodes, anodes, and/or cathodes. These components may benefit from the tight control of particle size, particle size distribution, and high chemical purity materials, which are advantageously disclosed herein.

Disclosed herein are materials and methods for producing lithium oxide materials, such as LLZO, having small particle sizes and high densities for lithium ion batteries. In some embodiments, a method according to embodiments herein may include a calcination process in which the starting material is heated in the presence of hydrogen, with or without oxygen. In some embodiments, the starting materials may be synthesized using a microwave plasma process that may produce a multi-phase starting material comprising lithium carbonate and a metal oxide having an average particle size between about 20nm and about 1000 nm. In some embodiments, the multi-phase starting material may have a particle size of about 20nm, about 40nm, about 60nm, about 80nm, about 100nm, about 120nm, about 140nm, about 160nm, about 180nm, about 200nm, about 220nm, about 240nm, about 260nm, about 280nm, about 300nm, about 320nm, about 340nm, about 360nm, about 380nm, about 400nm, about 420nm, about 440nm, about 460nm, about 480nm, about 500nm, about 520nm, about 540nm, about 560nm, about 580nm, about 600nm, about 620nm, about 640nm, about 660nm, about 680nm, about 700nm, about 720nm, about 740nm, about 760nm, about 780nm, about 800nm, about 820nm, about 840nm, about 860nm, about 880nm, about 900nm, about 920nm, about 940nm, about 960nm, about 980nm, about 1000nm, or an average particle size of any value between the foregoing values. In some embodiments, the material is formed after calcining a heterogeneous material (e.g., lithium carbonate/La ₂ Zr ₂ O ₇ Multiphase material) the lithium carbonate of the multiphase material may decompose to form lithium oxide. In some embodiments, the presence of hydrogen allows the heterogeneous material to be calcined at a temperature below the melting point of lithium carbonate. In some embodiments, the plasma treatment may produce a unique starting multiphase material that is not available from other production methods. In particular, the plasma treatment may produce a material comprising a mixture of carbonate and oxide within a single particle. Materials derived from the use of other production methods instead exhibit separate particles of lithium carbonate and oxide. During heat treatment, a plasma treated multiphase material comprising mixed phase particles will desirably form LLZO with less sintering/growth than a material made from separate phase particles. In some embodiments, reduced sintering and growth in the final LLZO material is a benefit.

In some embodiments, at least a portion of the lithium carbonate may be converted to lithium oxide via a calcination process during which the multi-phase starting material may be heated at a temperature below the melting point of the lithium carbonate. For example, in some embodiments, more than 50%, more than 60%, more than 70%, more than 75%, more than 80%, more than 85%, more than 90%, more than 95%, more than 99%, or more than 99% by weight of lithium carbonate may be converted to lithium oxide during heating of lithium carbonate in the presence of hydrogen gas. In some embodiments, after converting at least a portion of the lithium carbonate to lithium oxide, the temperature of the process may be raised to a higher temperature, sometimes above the melting point of lithium carbonate (e.g., above 723 ℃) to rapidly crystallize the lithium oxide and metal oxide, growing dense LLZO particles. In some embodiments, a dense LLZO film may be formed. In some embodiments, the calcination temperatures used in the methods described herein may be significantly lower than conventional calcination methods due to the presence of hydrogen. These lower temperatures have various beneficial effects, including reduced production costs by reduced energy usage and reduced lithium loss, and improved quality of the produced material due to reduced sintering during the calcination stage.

In some embodiments, microwave plasma processes and apparatus can be used to produce materials that contain very small particles of multiphase materials that contain lithium carbonate and one or more metal oxides. If such material is directly sintered, a material of the main LLZO can be formed. However, it is difficult to obtain a dense LLZO film due to the gas generated from the carbonate during sintering. In some embodiments, the methods described herein can produce a material that produces little gas and readily closes the pores to be sufficiently dense when cast and sintered.

Thus, in some embodiments, a gap heat treatment step (i.e., calcination) may be used to decompose the lithium carbonate of the starting material into oxides prior to casting the material into a film. In some embodiments, it may be critical to keep the small particles during this step so that the particles cast well and sinter together easily into a film. When this decomposition is performed under standard conditions (e.g., at O ₂ Or N ₂ 700 c in the atmosphere) there is significant particle sintering such that the particles may grow from about 200nm to about 1.5um and many particles fuse together. Thus, in some embodiments, the heat treatment includes heating the starting material at a temperature below the melting point of lithium carbonate to prevent such growth and sintering. Typically, lithium carbonate does not decompose below its melting point. However, in some embodiments, when subjected to heat treatment in the presence of hydrogen, it has been found that lithium carbonate may decompose into lithium oxide with little particle growth at temperatures as low as 600 ℃ or even lower, depending on the concentration of hydrogen. For example, lithium carbonate may be used 3%H in a nitrogen atmosphere ₂ Decomposition at a temperature of 620 ℃. As a result, in some embodiments, the resulting material may have a sufficiently small particle size to cast well into a dense film. In some embodiments, the material may be capable of less lithium loss and less crystallization at lower calcination temperatures at lower cost than conventional methodsGrain growth forms a viable dense film.

Typical methods for LLZO materials result in poor packing of the material in the green state, poor particle-to-particle contact, low driving force for sintering due to large particle size, and poor coordination of the particles with other particles. The green state may be defined as particles after formation but before sintering. In the production of LLZO powder by milling and/or spray pyrolysis, rapid full density sintering of defect free spacers may not occur. For example, separators produced with LLZO prepared by these methods may have residual porosity and large particle size distribution, which may lead to early failure.

A high quality LLZO can be prepared from starting materials by plasma treatment, such as microwave plasma treatment. LLZO that has been treated with starting materials produced by plasma treatment can include spherical particles having a tight size distribution (e.g., between 20nm and 1000 nm), a desired stoichiometry, and different crystal structures. In some embodiments, LLZO prepared using the starting materials herein can have fine particle sizes that exhibit a greater driving force for densification of the material during sintering, which facilitates reduced sintering times and reduced temperatures compared to conventionally prepared LLZO materials. The tight particle size distribution and spherical morphology can allow for high packing fraction, thereby increasing sintering speed. In addition, the compact particle size and spherical morphology may reduce the occurrence of stable voids that cannot be sintered. Less stable voids may result in improved final quality of the material. The tight size distribution may also cause controlled grain growth, which prevents abnormal growth, which produces oversized grains, and results in a broad grain size distribution.

Plasma treatment

In some embodiments, the starting materials used to produce the starting materials for calcination may be metal salts of the relevant elements, such as nitrates and acetates of lithium, lanthanum, zirconium, tantalum and aluminum. These salts may be dissolved and mixed in the appropriate proportions to produce the desired stoichiometry. In some embodiments, mixtures of metal salts may be used.

In some embodiments, nitrates of lanthanum, lithium, and aluminum can be mixed with acetates of zirconium to produce a solution feedstock and to produce the desired stoichiometry. In some embodiments, lithium hydroxide may be used to increase the percentage of lithium in the salt as compared to lithium nitrate. In some embodiments, the other starting materials for producing the starting materials for the calcined material may be lithium-free ceramic powder particles mixed with a dispersion medium and having a size in the range of 20-1000nm in a carrier solution to produce a dispersion, suspension, slurry, or similar mixture. The carrier solution may be water, alcohol or other non-polar solvent.

In some embodiments, lithium carbonate may be partially dissolved in a carrier solution and mixed with stoichiometric proportions of lanthanum oxide, zirconium oxide, and aluminum oxide mixed in water and a dispersion medium such as Triton X to form a stable suspension. In some embodiments, the dispersion or slurry may comprise a combination of ceramic oxide powders mixed with a soluble metal salt. Lithium nitrate and lanthanum nitrate can be mixed with zirconium oxide and aluminum oxide in water to form a slurry.

The solution precursor may be formed by dissolving the metal salts of lithium, lanthanum, zirconium and dopants of interest (e.g., aluminum) in a stoichiometric ratio in a solvent, such as water, or, in the case of a dispersion, dispersing the powder in a carrier solution. The amount of each salt can be calculated to give the desired final stoichiometry of the LLZO material to be prepared. In the case of dopants, the stoichiometry of the formula can be adjusted accordingly. In some embodiments, aluminum replaces lithium in the LLZO structure. In some embodiments, lithium or lanthanum may evaporate during processing, which may reduce the yield of metal in the final product. The amount of metal salt can be increased to compensate for the evaporated metal.

Fig. 1 illustrates an exemplary microwave plasma torch that may be used to produce materials according to embodiments of the present disclosure. As discussed above, the feed materials 9,10 may be introduced into a microwave plasma torch 3 in the introduction zone 3, the plasma torch 3 maintaining a microwave-generated plasma 11. In one example embodiment, an entrained gas stream and sheath flow (downward arrow) may be injected through inlet 5 to create flow conditions within the plasma torch 2 prior to igniting the plasma 11 via the microwave radiation source 1.

In some embodiments, both the entrained flow and the sheath flow are axisymmetric and laminar, while in other embodiments, the gas flow is turbulent. The feeds 9 are introduced axially into the microwave plasma torch 2 where they are entrained by the gas flow directing the material towards the plasma hot zone 6. As discussed above, the gas stream may be composed of a rare gas train of the periodic table of elements, such as helium, neon, argon, and the like. In a microwave-generated plasma, the feed material is melted to spheroidize the material. The inlet 5 may be used to direct a process gas to entrain and accelerate particles 9,10 along axis 12 towards the plasma 11. First, the particles 9 are accelerated by entrainment with a core laminar gas flow (upper set of arrows) created through the annular gap within the plasma torch. A second laminar flow (lower set of arrows) can be created through the second annular gap to provide a laminar sheath to the inner wall of the dielectric torch to protect it from melting due to thermal radiation from the plasma 11. In an exemplary embodiment, the laminar flow directs the particles 9,10 toward the plasma 11 along a path as close as possible to the axis 12, exposing them to a substantially uniform temperature within the plasma.

In some embodiments, suitable flow conditions exist to prevent particles 10 from reaching the inner wall of the plasma torch 2 where plasma attachment may occur. The particles 9,10 are guided by the gas flow to the microwave plasma 11, where they are each subjected to a uniform heat treatment. Various parameters of the microwave-generated plasma, as well as particle parameters, may be adjusted to achieve desired results. These parameters may include microwave power, feed material size, feed material insertion rate, gas flow rate, plasma temperature, residence time, and cooling rate. In some embodiments, the cooling or quenching rate upon exiting the plasma 11 is not less than 10 ⁺³ DEG C/sec. As discussed above, in this particular embodiment, the gas flow is laminar; however, in alternative embodiments, a vortex or turbulence may be used to direct the feed material to the plasma.

Fig. 2A-B illustrate an exemplary microwave plasma torch that includes a side feed hopper instead of the top feed hopper shown in the embodiment of fig. 1, thus allowing for downstream feed. Thus, in this implementation, the feedstock is injected after the microwave plasma torch applicator for treatment in the "plume" or "exhaust" of the microwave plasma torch. Thus, the plasma of the microwave plasma torch is joined at the outlet end of the plasma torch to allow for downstream feeding of feedstock, as opposed to the top feed (or upstream feed) discussed with respect to fig. 1. Such downstream feed can advantageously extend the life of the torch because the hot zone is infinitely protected from any material deposits on the hot zone liner walls. Furthermore, it joins the plasma plume downstream at a temperature suitable for optimal melting of the powder, through precise guiding of the temperature level and residence time. For example, the length of the plume can be adjusted with the microwave powder, gas flow, and pressure in the quench vessel containing the plasma plume.

In general, downstream spheroidization methods can utilize two main hardware configurations to establish a stable plasma plume, which are: a ring torch as described in U.S. patent publication No. 2018/0297122, or a swirl torch as described in US 8748785 B2 and US 9932673 B2. A feed system, tightly coupled with the plasma plume at the plasma torch outlet, is used for axisymmetrically feeding the powder to maintain process uniformity.

Other feed configurations may include one or several individual feed nozzles surrounding the plasma plume. The raw powder may enter the plasma at one point from any direction and may be fed to a point within the plasma from any direction 360 ° around the plasma. The feedstock powder may enter the plasma at a specific location along the length of the plasma plume, where a specific temperature has been measured and the residence time for the particles to fully melt is estimated. The melted particles leave the plasma and enter a sealed chamber where they are quenched and then collected.

A feed material 314 may be introduced into the microwave plasma torch 302. The hopper 306 may store the feed material 314 prior to feeding the feed material 314 into the microwave plasma torch 302, plume, or exhaust. The feed 314 can be injected at any angle, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 degrees, from the longitudinal direction of the plasma torch 302. In some embodiments, the feedstock may be injected at an angle greater than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 degrees. In some embodiments, the feedstock may be injected at an angle of less than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 degrees. In alternative embodiments, the feedstock may be injected along the longitudinal axis of the plasma torch.

Microwave radiation may be brought into the plasma torch through the waveguide 304. A feed material 314 is fed into the plasma chamber 310 and is contacted with the plasma generated by the plasma torch 302. The feed material melts when contacted with the plasma, plasma plume, or plasma exhaust. While still in the plasma chamber 310, the feed material 314 cools and solidifies before collection into vessel 312. Alternatively, the feed material 314 may leave the plasma chamber 310 while still in the melt phase to cool and solidify outside the plasma chamber. In some embodiments, a quenching chamber may be used, which may or may not use positive pressure. Although described separately from fig. 1, the embodiment of fig. 2A and 2B should be understood to use similar components and conditions as the embodiment of fig. 1.

As each droplet heats up in the plasma hot zone created by the microwave plasma torch, the solvent may evaporate, the solute may precipitate, and pyrolysis may occur. Pyrolysis under an oxygen plasma may produce oxides made of lithium, lanthanum, zirconium, and dopant choices M1 and M2. The plasma gas may be oxygen, but alternatively may be a blend of up to three gases with a minimum oxygen concentration of 1%. In some embodiments, one of the up to three gases is argon.

Spheroidization

In some embodiments, the final particles obtained by plasma treatment may be spherical or spheroid, and these terms may be used interchangeably. Advantageously, by using the key and specific disclosure associated with each of the different disclosed raw materials, all raw materials can be converted into spherical powders.

Embodiments of the present disclosure relate to producing particles that are substantially spherical or spheroid or have undergone significant spheroidization. In some embodiments, spherical, spheroid, or spheroidized particles refer to particles having a particle size greater than a certain particle sizeThreshold sphericity of particles. The sphericity of the particles can be calculated by calculating the surface area A of the sphere using the volume V of the matching particles using the following formula _{s, ideal} To calculate:

A _{s, ideal} ＝4πr _{Ideal for} ²

Then comparing the ideal surface area with the measured surface area A of the particles _{s actual} ：

In some embodiments, the particles may have a sphericity (also referred to herein as sphericity factor) of greater than 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, 0.91, 0.95, or 0.99 (or greater than about 0.5, about 0.6, about 0.7, about 0.75, about 0.8, about 0.91, about 0.95, or about 0.99). In some embodiments, the particles may have a sphericity of 0.75 or greater or 0.91 or greater (or about 0.75 or greater or about 0.91 or greater). In some embodiments, the particles may have a sphericity of less than 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, 0.91, 0.95, or 0.99 (or less than about 0.5, about 0.6, about 0.7, about 0.75, about 0.8, about 0.91, about 0.95, or about 0.99). In some embodiments, a particle is considered spherical, spheroidized, or spheroidized if it has a sphericity at or above any of the aforementioned sphericity values, while in some preferred embodiments, a particle is considered spherical if its sphericity is at or about 0.75 or greater or at or about 0.91 or greater.

In some embodiments, the median sphericity of all particles within a given powder may be greater than 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, 0.91, 0.95, or 0.99 (or greater than about 0.5, about 0.6, about 0.7, about 0.75, about 0.8, about 0.91, about 0.95, or about 0.99). In some embodiments, the median sphericity of all particles within a given powder may be less than 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, 0.91, 0.95, or 0.99 (or less than about 0.5, about 0.6, about 0.7, about 0.75, about 0.8, about 0.91, about 0.95, or about 0.99). In some embodiments, a powder is considered spheroidized if all or a threshold percentage of the particles measured with respect to a given powder (as described by any of the fractions below) have a median sphericity greater than or equal to any of the aforementioned sphericity values, and in some preferred embodiments, a powder is considered spheroidized if all or a threshold percentage of the particles have a median sphericity at or about 0.75 or greater or at or about 0.91 or greater.

In some embodiments, the fraction of particles within the powder that may be above a given sphericity threshold (as described above) may be greater than 50%, 60%, 70%, 80%, 90%, 95%, or 99% (or greater than about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99%). In some embodiments, the fraction of particles within the powder that may be above a given sphericity threshold (as described above) may be less than 50%, 60%, 70%, 80%, 90%, 95%, or 99% (or less than about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99%).

Particle size distribution and sphericity can be determined by any suitable known technique, such as by SEM, optical microscopy, dynamic light scattering, laser diffraction, manual measurement of dimensions using image analysis software (e.g., about 15-30 measurements from each of at least three images of the same material slice or sample), and any other technique.

Examples

Fig. 3A is an electron micrograph of a multiphase starting material produced by a microwave plasma process according to some embodiments described herein. In some embodiments, using the above-described methods, spherical multiphase starting materials can be synthesized that have very small particles and include a mixture of carbonate and oxide within a single particle.

Fig. 3B is a phase identification of a multiphase starting material prepared by a microwave plasma process via X-ray diffraction according to some embodiments herein. As shown in fig. 3B, in some embodiments, a multiphase material may be formed in which at least lanthanum zirconate, lithium carbonate, lanthanum aluminate, lithium alumina, and lanthanum dioxide carbonate are present within a single particle.

Fig. 4A-B are electron micrographs of LLZO materials calcined in the presence of hydrogen. As mentioned above, high quality LLZO materials formed with plasma treated, multi-phase starting materials that are calcined in the presence of hydrogen and then crystallized can be produced. In particular, LLZO materials formed according to the methods described herein can include spherical particles having a tight size distribution (e.g., between 20nm and 1000 nm), a desired stoichiometry, and different crystal structures. In some embodiments, LLZO prepared using the starting materials herein can have fine particle sizes that exhibit a greater driving force for densification of the material during sintering, which facilitates reduced sintering times and reduced temperatures compared to conventionally prepared LLZO materials. The tight particle size distribution and spherical morphology can allow for high packing fraction, thereby increasing sintering speed.

Fig. 4C is a phase identification of LLZO materials calcined in the presence of hydrogen via x-ray diffraction. As shown, LLZO materials produced using the methods described herein can comprise various phases, but typically at least about 75% by weight, at least about 80% by weight, at least about 85% by weight, at least about 90% by weight, at least about 95% by weight, or at least about 99% by weight LLZO, other phases including lanthanum zirconate, lanthanum alumina, lanthanum lithium aluminum oxide, and very small amounts of lanthanum carbonate oxide.

Fig. 5A-B are electron micrographs of LLZO materials calcined in the presence of hydrogen and oxygen according to some embodiments described herein. Fig. 5C is a phase identification of LLZO materials calcined in the presence of hydrogen and oxygen via x-ray diffraction. In some embodiments, the plasma treated multiphase material can be calcined in the presence of hydrogen and oxygen to form cubic LLZO. Other phases of the LLZO material may include lanthanum zirconate, lanthanum aluminate, and zirconia.

Additional embodiments

In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Indeed, although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while several variations of the embodiments of the invention have been shown and described in detail, other modifications within the scope of the invention will be apparent to those skilled in the art based on this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed embodiments of the invention. Any of the methods disclosed herein do not have to be performed in the order described. Therefore, it is intended that the scope of the invention herein disclosed should not be limited by the particular embodiments described above.

It should be understood that the systems and methods of the present disclosure each have several innovative aspects, none of which are solely responsible for the desirable attributes disclosed herein or are required. The various features and methods described above may be used independently of each other or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure.

Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. No single feature or group of features is essential to each and every embodiment.

It will be further understood that the terms "may," "might," "could," "for example," etc., as used herein, are generally intended to convey that certain embodiments include certain features, elements, and/or steps, among others, unless expressly stated otherwise or otherwise understood within the context of the use. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic with or without author input or prompting decisions whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The words "comprising," "including," "having," and the like are synonymous and are used in an open-ended fashion, and do not exclude additional elements, features, acts, operations, etc. Furthermore, the word "or" is used in its inclusive sense (rather than its exclusive sense) such that when used in connection with a list of elements, for example, the word "or" means one, some, or all of the elements in the list. Furthermore, the articles "a," "an," and "the" as used in this application and the appended claims should be construed to mean "one or more" or "at least one" unless specified otherwise. Similarly, although operations may be depicted in the drawings in a particular order, it should be understood that such operations are not necessarily performed in the particular order shown or in sequential order, or that all illustrated operations are performed, to achieve desirable results. Additionally, the figures may schematically depict one or more example methods in flow chart form. However, other operations not depicted may be incorporated into the example methods and processes schematically illustrated. For example, one or more additional operations may be performed before, after, concurrently with, or between any of the illustrated operations. In addition, the operations may be rearranged or reordered in other implementations. In some cases, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems can generally be integrated together in a single software product or packaged into multiple software products. In addition, other embodiments are within the scope of the following claims. In some cases, the operations recited in the claims may be performed in a different order and still achieve desirable results.

Further, while the methods and apparatus described herein are susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various implementations and the appended claims. In addition, the disclosure of any particular feature, aspect, method, property, characteristic, quality, attribute, element, etc. described herein in connection with an implementation or embodiment may be used with all other implementations or embodiments described herein. Any of the methods disclosed herein do not have to be performed in the order described. The methods disclosed herein may include certain actions taken by a practitioner; however, the method may also include any third party instructions for those operations, whether explicitly indicated or implied. The scope of the disclosure also encompasses any and all overlaps, sub-ranges, and combinations thereof. Language such as "up to", "at least", "greater than", "less than", "between" includes the recited numbers. The inclusion of a number preceded by a word such as "about" or "approximately" includes the number and should be interpreted as appropriate (e.g., as reasonably accurate as possible in these cases, such as ± 5%, ± 10%, ± 15%, etc.). For example, "about 3.5mm" includes "3.5mm". Phrases preceded by words such as "basic" include the phrase and should be interpreted according to circumstances (e.g., as much as reasonably possible in these circumstances). For example, "substantially constant" includes "constant". All measurements are under standard conditions, including temperature and pressure, unless otherwise specified.

As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including individual members. For example, "at least one of A, B or C" is intended to cover: A. b, C, A and B, A and C, B and C and A, B and C. The connection language, such as the phrase "at least one of X, Y and Z," is to be understood with respect to the context as generally used to express items, terms, etc., may be at least one of X, Y or Z, unless explicitly stated otherwise. Thus, such connection language is not generally intended to imply that certain embodiments require the presence of at least one X, at least one Y, and at least one Z, respectively. The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.

Thus, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with the disclosure, principles and novel features disclosed herein.

Claims

1. A method for producing a solid electrolyte material, the method comprising:

heating a multiphase material comprising lithium carbonate in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide; and is also provided with

The lithium oxide is heated to a temperature sufficient to crystallize the lithium oxide to form a solid electrolyte material comprising Lithium Lanthanum Zirconium Oxide (LLZO) particles.

2. The method of claim 1, wherein the multiphase material has an average particle size between about 20nm and about 1000 nm.

3. The method of claim 1, wherein the multiphase material has an average particle size of about 300nm.

4. The method of claim 1, wherein the multiphase material further comprises lanthanum (La).

5. The method of claim 1, wherein the multiphase material further comprises zirconium (Zr).

6. The method of claim 1, wherein the multiphase material further comprises lanthanum (La) and zirconium (Zr).

7. The method of claim 1, wherein the multiphase material further comprises lanthanum zirconium oxide.

8. The method of claim 7, wherein the multiphase material further comprises La ₂ Zr ₂ O ₇ 。

9. The method of claim 1, wherein the LLZO further comprises one or more dopants.

10. The method of claim 9, wherein the one or more dopants comprise at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), or boron (B).

11. The method of claim 1, wherein the LLZO further comprises LaAlO ₃ Or La (La) ₂ (Li _0.5 Al _0.5 )O ₄ At least one of them.

12. The method of claim 1, wherein the multiphase material further comprises lialalao ₂ 、Li ₂ ZrO ₃ 、ZrO ₂ 、LaAlO ₃ 、Li ₂ Zr ₂ O ₇ 、La ₂ O ₃ 、La ₂ (Li _0.5 Al _0.5 )O ₄ 、LiLaO ₂ 、Li ₅ AlO ₄ 、La ₂ O ₂ CO ₃ Or Li (lithium) _a Zr _b O _c At least one of which is 1.ltoreq.a.ltoreq.8, 1.ltoreq.b.ltoreq.2, and 1.ltoreq.c.ltoreq.7.

13. The method of claim 1, wherein the solid electrolyte material further comprises one or more dopants.

14. The method of claim 1, wherein the one or more dopants comprise at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), or boron (B).

15. The method of claim 1, wherein the solid electrolyte material has an average particle size between about 20nm and about 1000 nm.

16. The method of claim 1, wherein the solid electrolyte material has an average particle size of about 300nm.

17. The method of claim 1, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 50% by weight of lithium carbonate in the multiphase material.

18. The method of claim 1, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 75% by weight of lithium carbonate in the multiphase material.

19. The method of claim 1, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 90% by weight of lithium carbonate in the multiphase material.

20. The method of claim 1, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 99% by weight of lithium carbonate in the multiphase material.

21. The method of claim 1, wherein the total time of heating of the multiphase material and heating of the lithium oxide is between about 2 hours and about 20 hours.

22. The method of claim 1, wherein the multiphase material is heated for between about 1 hour and about 10 hours.

23. The method of claim 1, wherein the lithium oxide is heated for between about 1 hour and about 10 hours.

24. The method of claim 1, further comprising forming a thin film from a solid electrolyte material.

25. The method of claim 1, wherein at least a portion of the lithium carbonate forms a lithium peroxide upon heating the multiphase material.

26. The method of claim 1, wherein the lithium oxide is heated at a temperature greater than 600 ℃.

27. The method of claim 1, wherein the lithium oxide is heated to a temperature above 640 ℃.

28. The method according to claim 1, wherein the lithium oxide is heated in an oxygen-containing atmosphere.

29. The method of claim 1, wherein the lithium oxide is heated in the absence of hydrogen.

30. The method of claim 1, wherein the amount of lithium lost during the process is less than 3% by weight.

31. The method of claim 1, further comprising forming the multiphase material with a microwave plasma process, the microwave plasma process comprising:

inputting one or more feedstock materials into a microwave-generated plasma to form a multiphase material; and is also provided with

The multiphase material is collected.

32. A method for producing Lithium Lanthanum Zirconium Oxide (LLZO) particles, the method comprising:

heating a mixture comprising lithium carbonate and La in the presence of hydrogen at a temperature below the melting point of lithium carbonate ₂ Zr ₂ O ₇ Such that at least a portion of the lithium carbonate decomposes to form lithium oxide; and is also provided with

The lithium oxide is heated to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

33. The method of claim 32, wherein the multiphase material has an average particle size between about 20nm and about 1000 nm.

34. The method of claim 32, wherein the multiphase material has an average particle size of about 300nm.

35. The method of claim 32, wherein the LLZO further comprises one or more dopants.

36. The method of claim 35, wherein the one or more dopants comprise at least one of aluminum (Al), tantalum (Ta), niobium (Nb), gallium (Ga), and boron (B).

37. The method of claim 32, wherein the LLZO comprises LaAlO ₃ Or La (La) ₂ (Li _0.5 Al _0.5 )O ₄ At least one of them.

38. The method of claim 32, wherein the multiphase material further comprises lialalao ₂ 、Li ₂ ZrO ₃ 、ZrO ₂ 、LaAlO ₃ 、La ₂ O ₃ 、La ₂ (Li _0.5 Al _0.5 )O ₄ 、LiLaO ₂ 、Li ₅ AlO ₄ 、La ₂ O ₂ CO ₃ Or Li (lithium) _a Zr _b O _c At least one of which is 1.ltoreq.a.ltoreq.8, 1.ltoreq.b.ltoreq.2, and 1.ltoreq.c.ltoreq.7.

39. The method of claim 32, wherein the LLZO has an average particle size between about 20nm and about 1000 nm.

40. The method of claim 32, wherein the LLZO has an average particle size of about 300nm.

41. The method of claim 32, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 50% by weight of lithium carbonate in the multiphase material.

42. The method of claim 32, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 75% by weight of lithium carbonate in the multiphase material.

43. The method of claim 32, wherein the portion of the lithium carbonate that decomposes to form lithium oxide is at least 90% by weight of the lithium carbonate in the multiphase material.

44. The method of claim 32, wherein the portion of lithium carbonate that decomposes to form lithium oxide is at least 99% by weight of lithium carbonate in the multiphase material.

45. The method of claim 32, wherein the total time of heating of the multiphase material and heating of the lithium oxide is between about 2 hours and about 20 hours.

46. The method of claim 32, wherein the multiphase material is heated for between about 1 hour and about 10 hours.

47. The method of claim 32, wherein the lithium oxide is heated for between about 1 hour and about 10 hours.

48. The method of claim 32, further comprising forming a film from LLZO particles.

49. The method of claim 32, wherein at least a portion of the lithium carbonate forms a lithium peroxide upon heating the multiphase material.

50. The method of claim 32, wherein the lithium oxide is heated at a temperature greater than 600 ℃.

51. The method of claim 32, wherein the lithium oxide is heated to a temperature above 640 ℃.

52. The method of claim 32, wherein the lithium oxide is heated in an oxygen-containing atmosphere.

53. The method of claim 32, wherein the lithium oxide is heated in the absence of hydrogen.

54. The method of claim 32, wherein the amount of lithium lost during the process is less than 3% by weight.

55. The method of claim 32, further comprising forming the multiphase material with a microwave plasma process, the microwave plasma process comprising:

The multiphase material is collected.

56. A method of producing a multiphase material, the method comprising:

preparing a feedstock comprising lanthanum and zirconium;

introducing a feedstock into a microwave plasma torch, a plasma plume of the microwave plasma torch, and/or an exhaust of the microwave plasma torch; and is also provided with

The feedstock is heated in the microwave plasma torch, the plasma plume of the microwave plasma torch, and/or the exhaust of the microwave plasma torch to form a multi-phase material comprising lithium carbonate and lanthanum zirconate.

57. A method according to claim 56, wherein the multiphase material further comprises at least one of lanthanum aluminate, lithium aluminum oxide, and lanthanum carbonate dioxide.

58. A method according to claim 56, wherein the multiphase material comprises phases of lithium carbonate and lanthanum zirconate within individual particles of the multiphase material.

59. The method of claim 56, further comprising heating the multiphase material in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide.

60. The method of claim 59, further comprising heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

61. A multiphase material comprising lithium carbonate and lanthanum zirconate within individual particles of the multiphase material.

62. The multiphase material of claim 61, wherein the multiphase material is formed by a process comprising:

preparing a feedstock comprising lanthanum and zirconium;

The feedstock is heated in the microwave plasma torch, a plasma plume of the microwave plasma torch, and/or an exhaust of the microwave plasma torch to form a multiphase material.

63. The multiphase material of claim 62, wherein the process further comprises heating the multiphase material in the presence of hydrogen gas at a temperature below the melting point of lithium carbonate such that at least a portion of the lithium carbonate decomposes to form lithium oxide.

64. The multiphase material of claim 63, wherein the process further comprises heating the lithium oxide to a temperature sufficient to crystallize the lithium oxide to form Lithium Lanthanum Zirconium Oxide (LLZO) particles.

65. A multiphase material according to claim 61, wherein the multiphase material further comprises at least one of lanthanum aluminate, lithium aluminum oxide, and lanthanum carbonate dioxide.

66. The multiphase material of claim 61, wherein the multiphase material comprises phases of lithium carbonate and lanthanum zirconate within individual particles of the multiphase material.

67. A Lithium Lanthanum Zirconium Oxide (LLZO) material formed by a method comprising: