Disordered rock salt materials and methods of forming the same

Abstract

A composite particle composed of spinel and disordered rock salt domains interspersed therein, made by removing lithium from a disordered rock salt to form a lithium deficient disordered rock salt and heating the lithium deficient disordered rock salt for a time and temperature to form the composite particle.

Description

Technical Field

[0001] This invention belongs to the field of battery technology. Background Technology

[0002] Lithium metal oxides have been used to formulate cathode materials for lithium-ion batteries. Cathodes are derived from several basic crystal structure types, such as spinel, olivine, and layered oxide structures. Layered oxide structures include lithium-excess structures, where additional lithium is present in the structure.

[0003] Recently, attention has focused on disordered rock salt structures, such as those formed from specific lithium metal oxides. One such compound is represented by the following formula: Where M is a divalent or trivalent cation, it has shown promise as a class of transition metal oxides for use as cathodes in lithium-ion batteries. Compounds of formula (1) are considered disordered rock salts, in which random atomic arrangements of lithium and transition metal ions are packed in a close-packed cubic structure. These disordered rock salt compositions offer the ability to contain up to 3 lithium atoms per molecular unit, which is more than conventional excess lithium layered materials. Formula (1) can be converted and represented as Li x M y N z O w .

[0004] Disordered rock salt structures are attractive cathode materials for next-generation lithium-ion batteries because they exhibit higher specific energy density (e.g., higher theoretical energy density) compared to state-of-the-art cathode materials such as layered lithium metal oxide structures. For example, some disordered rock salt structure materials have a theoretical gravimetric energy density of approximately 1120 Wh / kg, while LiMn₂O₄ active materials have a theoretical gravimetric energy density of approximately 492 Wh / kg. 1.5 Ni 0.5 The theoretical gravimetric energy density of O4 is approximately 691 Wh / kg. This energy density is particularly attractive when using lower-cost raw materials as components of the disordered rock salt structure, such as manganese, which can be combined with other transition metals. Therefore, disordered rock salt materials (DR) can achieve relatively high energy densities at relatively low material costs. To achieve comparable energy densities, known cathode materials require higher-cost raw materials, such as cobalt or nickel.

[0005] Unfortunately, due to the low Li diffusivity of these materials, DR materials require submicron particle sizes. This leads to poor capacity and voltage retention in these DR materials, primarily due to the poorly controlled, severely fragmented nanoparticle morphology introduced during DR material preparation. The fragmented particle morphology of DR often accelerates electrolyte decomposition and Mn (if present) dissolution into the electrolyte, resulting in shortened cycle life. Furthermore, the fragmented particle morphology can lead to low electrode density, thereby reducing the volumetric energy density of the DR material on the current collector, which forms the typical cathode in the battery.

[0006] Therefore, it is desirable to provide particles with a DR structure that avoid one or more of the problems of the prior art DR, as well as a battery composed of a disordered rock salt cathode that has improved features such as longer cycle life, high volumetric density, improved processing and power output. Summary of the Invention

[0007] By heating lithium-deficient disordered rock salt particles (DDR), dispersed spinel or monoclinic crystals and disordered rock domains can be formed into particles (composite particles "CP"). DDR is typically lithium-deficient on the surface. It is understood that nanodomains may consist of spinel, monoclinic, and rock salt phases, but due to the overlapping diffraction peaks of the spinel and monoclinic phases, bulk X-ray diffraction techniques may be insufficient to detect these two phases. DDR can be produced via solid-state thermal synthesis, followed by Li removal from the DR structure through heat treatment in oxygen at a lower temperature, followed by washing to remove the formed surface lithium material, such as lithium carbonate and lithium hydroxide. DDR can be produced by synthesizing DR in molten salt and then washing to form DDR ("salt method"). That is, the salt method may unexpectedly form DDR directly (i.e., without heat treatment in the presence of oxygen at temperatures below the synthesis temperature, even if such further treatment is required). DDR is then heat-treated to form CP in an oxygen- or oxygen-free atmosphere.

[0008] The illustrative CP comprises dispersed spinel or monoclinic crystals and disordered rock salt domains smaller than 100 nanometers (“nanodomains”). The presence of spinel or monoclinic crystals and DR structures in the particulate powder can be determined by X-ray diffraction. The particle size and distribution of nanodomains within the particles can be determined by focused ion beam (FIB) cross-sectional analysis using high-resolution transmission electron microscopy (HRTEM) with flat-field filtering and inverse Fast Fourier Transform (FFT) of the HRTEM images.

[0009] The illustrative CP can be prepared by heating lithium-deficient disordered rock salt (DDR) particles to a transition time and temperature sufficient for CP formation, the CP having nanodomains of spinel or monoclinic crystals and disordered rock salt dispersed in the composite material. The DDR particles have a chemical gradient of Li sufficient to initiate the formation of dispersed nanodomains within the DDR, thereby forming CP at a transition time and temperature much lower than that used to synthesize the disordered rock salt particles. Non-limitingly, when the DDR gradient is small or nonexistent, and the heat treatment is performed in air at temperatures exceeding 400°C to approximately 600°C, monoclinic domains may be more readily formed. CP can be used in primary and secondary lithium-ion batteries. DR powder can be used with any suitable battery assembly to form a lithium-ion battery in an electrolyte, the battery assembly including, for example, current collectors, separators, and anodes known in the art. Attached Figure Description

[0010] Figure 1 The X-ray diffraction patterns of disordered rock salt particles (not of this invention) and composite particles of this invention are shown.

[0011] Figure 2 This is a scanning electron microscope image of disordered rock salt particles that are not part of this invention.

[0012] Figure 3 A scanning electron micrograph of the composite particles of the present invention is shown.

[0013] Figure 4 A scanning electron micrograph of the composite particles of the present invention is shown.

[0014] Figure 5 The X-ray diffraction patterns of disordered rock salt particles (not of this invention) and composite particles of this invention are shown.

[0015] Figure 6 This is a scanning electron microscope image of disordered rock salt particles that are not part of this invention.

[0016] Figure 7 This is a scanning electron microscope image of disordered rock salt particles that are not part of this invention.

[0017] Figure 8 This is a scanning electron microscope image of disordered rock salt particles that are not part of this invention.

[0018] Figure 9 This is a scanning electron microscope image of the composite particles of the present invention.

[0019] Figure 10 This is a scanning electron microscope image of the composite particles of the present invention.

[0020] Figure 11 This is a transmission electron micrograph (TEM) of the composite particles of the present invention.

[0021] Figure 12 High-resolution transmission electron micrograph (HRTEM) of the cross-sectional composite particles of the present invention is shown.

[0022] Figure 13 Showing Figure 12 Flat-field filtering of HRTEM images using inverse Fast Fourier Transform (FFT).

[0023] Figure 14 Showing Figure 12 The electron diffraction pattern of the composite particles, in which spinel is represented in blue and the DR crystal structure is represented in yellow.

[0024] Figure 15 Showing Figure 12 Composite particles with DR and spinel domains on a 200 plane d Spatial relationship of spacing.

[0025] Figure 16 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of disordered rock salt particles not of this invention.

[0026] Figure 17A Figures B and C show the voltage distribution and capacity retention of the battery, which has a cathode made of composite particles of the present invention.

[0027] Figure 18 The capacity retention rate of the battery is shown, the battery having a cathode composed of composite particles of the present invention.

[0028] Figure 19 The X-ray diffraction patterns of disordered rock salt particles (not of this invention) and composite particles of this invention are shown.

[0029] Figure 20 Scanning electron micrographs of disordered rock salt particles not of this invention and composite particles of this invention are shown.

[0030] Figure 21 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of disordered rock salt particles not of this invention and composite particles of this invention.

[0031] Figure 22 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of disordered rock salt particles not of this invention and composite particles of this invention.

[0032] Figure 23 The X-ray diffraction pattern of the composite particles of the present invention is shown.

[0033] Figure 24 This is a scanning electron microscope image of the composite particles of the present invention.

[0034] Figure 25 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of composite particles of the present invention.

[0035] Figure 26 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of composite particles of the present invention.

[0036] Figure 27 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of composite particles of the present invention.

[0037] Figure 28 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of composite particles of the present invention.

[0038] Figure 29 The voltage distribution and capacity retention of the battery are shown, the battery having a cathode composed of composite particles of the present invention. Detailed Implementation

[0039] The following definitions apply to some aspects described with respect to certain embodiments of the invention. These definitions are also open to extension. Each term is further explained and illustrated by description, drawings, and examples. Any interpretation of the terms in this specification should be considered in light of the complete description, figures, and examples provided herein.

[0040] The singular terms “a,” “an,” and “the” include the plural unless the context explicitly specifies otherwise. Thus, for example, a reference to one object can contain multiple objects unless the context explicitly specifies otherwise.

[0041] The rate “C” refers (in context) to a fraction or multiple of the discharge current relative to a “1 C” current value (at which the battery (in a substantially fully charged state) will be substantially fully discharged in one hour), or a fraction or multiple of the charging current relative to a “1 C” current value (at which the battery (in a substantially fully discharged state) will be substantially fully charged in one hour).

[0042] In some battery characteristics that vary with temperature, such characteristics are specified at ambient temperatures of approximately 20 to approximately 30°C, unless the context clearly specifies otherwise.

[0043] The ranges presented herein include their endpoints. Thus, for example, the range of 1 to 3 includes the values 1 and 3 and intermediate values. When specifying a majority of a component, it means more than 50 mole % or (as readily understood from the context used) up to substantially all of the component (99% or less). That is, a majority of a component specifies that the specified component is present in an amount greater than 50% to 99%, 90%, 80%, 70%, or 60% of the component. Unless otherwise specified, when a minority of a component is the specified component, it is present in an amount less than 50% to about 1%, and the remainder is the majority of the specified component.

[0044] The CP is composed of dispersed spinel domains or monoclinic domains and disordered rock salt domains, and the domains are less than 100 nanometers (“nanodomains”). These domains are preferably less than 50 or 25 nanometers. Both spinel domains and monoclinic domains may coexist with the disordered rock salt domains. The characteristics of the domains and particles can be determined by the microscopic imaging techniques described herein. The CP typically exhibits a disordered rock salt d spacing of about 0.2 nm and a spinel or monoclinic d spacing of about 0.4 nm along the 200 plane.

[0045] The CP can be formed from any useful disordered rock salt, but is particularly useful for DRs composed of one or more of Ti, Mn, Fe, Co, V, Cr, Ni, and Cu. Illustratively, the CP can have a chemical structure represented by the formula: Li x M’ y M z O 2-(a+b) F a Z b where 1.0 < x < 1.75; 0 ≤ y < 0.55; 0.1 < z < 1; 0 ≤ (a + b) < 0.7; (b ≥ 0); M’ is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, and Sb; and Z is one or more of P, N, and S. Ideally, M is composed of one or more of Ti, Mn, Fe, Co, V, Cr, Ni, and Cu, and more ideally, M is composed of Mn. M’ ideally consists of at least one of Ti, Ta, and Nb.

[0046] Compared to conventionally ground DR powder, CP, when produced via the salt process, may lack the sharp roughness and be more rounded. Illustratively, CP may have the following roundness: The roundness of a single particle is defined as 4πA / P², where A is the area of ​​the particle and P is the perimeter of the particle, both observed from a random angle. Sphericity is a related parameter derived from the square root of roundness. Roundness is a value greater than zero and less than or equal to one. A perfectly round particle is referred to as having a roundness of 1.00. Population roundness data tables are presented in such a way that various roundness levels (e.g., 0.65, 0.75, 0.85, 0.90, and 0.95) are accompanied by the percentage of a population of particles with a roundness greater than the table value. Ideally, at least about 70%, 75%, or 80% of CP (by quantity) should have a roundness of at least about 0.65, 0.75, 0.8, or 0.85 (i.e., spherical as used herein).

[0047] The primary particle (CP) can be of any particle size and size distribution used in the battery; however, the dispersed nanodomains of the CP surprisingly allow for primary particle sizes much larger than those of typical pulverized dry diaphragm (DR) particles required to manufacture a useful battery. Typical DRs typically have particle sizes much smaller than 100 nm (average less than or equal to a 100 nm equivalent spherical diameter by volume or quantity). Generally, the average particle size is at most 20 micrometers, but typically the average primary particle size is at most about 2 to 0.1 micrometers. It has been found that CPs with particle sizes from 100 nm to 2 micrometers may have useful battery characteristics compared to typical DRs, where a particle size distribution by weight or volume of D90 of at most about 1.5 micrometers, D50 in the submicrometer range (e.g., less than 1 micrometer to about 0.1 micrometers), and D10 of at least 0.1 micrometers is particularly useful. Primary particles may agglomerate to form aggregates (secondary particles, such as those produced by spray drying, which may be further sintered if desired). Primary particles are discrete, unagglomerated particles, preferably having the aforementioned particle size distribution. Unaggregated particles are those that are easily sheared apart (inventory, at most particles bonded by van der Waals bonds and hydrogen bonds).

[0048] Particle size and shape can be measured by any suitable method known in the art, i.e., by measuring the diameter (equivalent spherical diameter). In some embodiments, particle size and shape are determined by laser diffraction known in the art. For example, a laser diffractometer (e.g., a Microtrac S3500 with a static image analysis accessory) can be used to determine particle size, which uses PartAnSI software to analyze captured particle images, or performs image analysis on scanning electron micrographs of the particles (e.g., counting at least 100 particles using image analysis software such as those described above).

[0049] When using the salt method described herein, CP may also consist of trace amounts of one or more of Na, K, Cs, Br, and Cl. Trace amounts here are quantities detectable by known macroscopic analytical techniques, such as inductively coupled plasma mass spectrometry. Trace amounts in this context are any quantities ranging from 100 parts per million to the analytical detection limit (e.g., parts per billion by weight).

[0050] Composite particles (CP) can be formed by heating lithium-deficient disordered rock salt (DDR) to a transition time and temperature sufficient for the formation of composite particles, which have spinel or monoclinic crystals, or both, dispersed within the composite particles and nanodomains of disordered rock salt. The transition temperature is much lower than the temperature required for the formation of disordered rock salt (e.g., 800°C or 900°C to 1200°C or 1100°C). Particularly useful transition temperatures are generally 300°C to 600°C. The transition time can be any useful time, among which those that do not lead to any harmful particle growth while still achieving nanodomains are ideal. Illustratively, the transition time can be 5 minutes, 15 minutes, 30 minutes, 60 minutes, 2 hours or 3 hours to 24 hours, 12 hours or 20 hours. The atmosphere can be still or flowing. The transition atmosphere can be any suitable, such as an inert gas (rare gas or nitrogen) or containing oxygen (air, oxygen or an inert gas / nitrogen with an oxygen partial pressure). When using an oxygen-containing atmosphere, DDR can be formed in situ and subsequently transformed into CP. When DDR is synthesized using the salt method and washed with a lithium hydroxide solution at a pH of at least 11 after annealing, at a transition temperature of at least 400°C or 500°C to 600°C, a CP with a monoclinic phase appears to form, but this is not limiting; it could be due to further development of the monoclinic superstructure, as shown by the X-ray diffraction peak centered at 21° 2θ (Cu). Depending on the transition metal in the disordered rock salt, the formation of this phase may also be more general. Illustratively, without any limitation, the presence of Ti appears to favor the formation of monoclinic domains at heating above 400°C, while the presence of Nb appears to be detrimental to the formation of a monoclinic phase under otherwise essentially identical conditions.

[0051] DDR particles are lithium-deficient. For example, lithium deficiency can be represented by a Li chemical gradient, given by the difference between the Li concentration in the outer 20% volume (outer) of the DDR and the Li concentration in the core 80% volume encapsulated by the outer volume, sufficient to induce DDR conversion to CP, where the lower amount of Li is particularly useful in the outer volume. The difference required to induce conversion within a practically feasible timeframe may be useful for a particular CP. Exemplary useful differences could be 1%, 5%, 10%, or 25% to 50%. The lithium concentration can be determined using electron microscopy.

[0052] DDR can be prepared by first forming disordered rock salt (DR) particles and, for example, removing lithium from the surface of the disordered rock salt particles. Exemplarily, lithium can be removed from the surface of the disordered rock salt particles by washing in neutral or alkaline water (e.g., where alkalis such as alkali metal hydroxides and ammonia are dissolved) and separating the washed particles from the water, for example, by filtration or sedimentation / centrifugation. Another example is the heat treatment of the DR particles, wherein the DR is heated in an oxygen-containing atmosphere at a temperature (e.g., 300°C to 500°C) much below the DR synthesis temperature (typically 800°C to 1200°C). Heating can be performed by any suitable heating method, such as those known in the art, including resistance heating, RF / microwave heating, induction coupling heating, and radiation heating. The oxygen-containing atmosphere can be any atmosphere containing sufficient oxygen to remove lithium from the DR. Typically, the amount of oxygen present is at least about 0.1 mole fraction or about 0.2 mole fraction; air is a specific example.

[0053] A particularly useful method for forming DR particles (“salt method”) involves heating a disordered rock salt precursor (DRP) and salt to a reaction temperature above the salt melting point, wherein the DRP / salt volume ratio is sufficient to form the desired DR powder, said ratio being at least 0.75, 1, 1.2, 1.4, 1.5 to any feasible amount, such as 5). Without limitation, said ratio is considered ideal in terms of limiting the solid-state reactions that may occur before the salt melts and having a sufficient amount of salt to adequately dissolve one or more DRPs to achieve the desired DR powder. Under heating conditions, the salt may preferentially dissolve one or more DRPs, such as DRP composed of Li or Mn. The salt method described herein has surprisingly produced cathode DR-containing particles with particle sizes much larger than typical DR pure particles. Exemplarily, the salt method can form composite particles with an average particle size of 0.1 micrometers to 2 micrometers, and said method allows the average particle size of the formed composite particles to be the same as or within 50% of the particle size of the DR or DDR from which it is made.

[0054] In the salting method described herein, both the salt and each type of DRP are powders. To facilitate the formation of the desired DR powder, each of these precursor powders has a similar particle size and particle size distribution, uniformly distributed in the precursor mixture (exemplarily, the salt / DRP ratio of 10 random samples is ideally within 20%, 10%, 5%, 2%, or 1% of each other). Similar particle size means that the average particle size of these powders is within one order of magnitude of each other, but preferably, the average particle size differs from each other by a factor of 5 or 2. Generally, the average particle size (volume) of the salt and DRP powders is at most about 20 micrometers, 15 micrometers, 10 micrometers, 5 micrometers, or 2 micrometers, down to at least about 0.1 micrometers. It may be ideal that the particle size (volume) of DRP lacking Mn and Li is smaller than that of DRP containing Li or Mn (e.g., an average particle size that is 5%, 10%, 20%, or 50% smaller).

[0055] When using the salt method, to achieve the desired particle size, particle size distribution, and morphology, the heating rate is desirably as fast as possible, and the time at the DR synthesis temperature is generally from 1, 2, 3, or 5 minutes to 30, 15, or 10 minutes.

[0056] In disordered rock salt, both lithium and transition metals occupy the cubic close-packed lattice of octahedral positions. In an electrochemical reaction, lithium diffusion proceeds by lithium jumping from one octahedral position via an intermediate tetrahedral position to another octahedral position. The lithium in the intermediate tetrahedral position is the activated state in lithium diffusion. The activated tetrahedral lithium ions share faces with the following four octahedral positions: (i) the position previously occupied by the lithium ion itself; (ii) the vacancy into which the lithium ion will enter; (iii and iv) two positions that can be occupied by lithium, transition metal, or vacancy.

[0057] The DR component required for DDR can be any useful DR, especially a DR composed of Mn or Mn and Ti. Illustratively, the DR and the subsequent CP made from the DR can be represented by the following formula: Li x M’ y M z O 2-(a+b) F a Z b where 1.0 < x < 1.75; 0 ≤ y < 0.55; 0.1 < z < 1; 0 ≤ (a + b) < 0.7; (b ≥ 0); M’ is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, Sn, Bi, and Sb; Z is one or more of P, N, and S. Other dopants may also be included, such as dopants that replace Li, such as Na and Mg, which can be any useful amount, but usually up to about 10 mol% or 5 mol% to 0.01 mol% of such dopants present in lithium and the DR or CP.

[0058] The amounts of F and Z can be the majority or minority of the anions (i.e., O, F, and one or more of P, S, and N). Illustratively, (a + b) is 0.05 to 1.5, 1, 0.95, 0.8, 0.65, 0.5. It may be desirable for a to be 0.05 to 0.25. Z can be any combination of P, N, and S, or just one of them. When two or more are present, the ratio between P, N, and S can be any useful ratio, depending on the properties sought. For example, when it is desired to lower the redox potential, it may be necessary to have S present. It may also be desirable for S to be the majority of P, S, and N present in the composition.

[0059] The composition may have any desired Li of 1 or more, but it may be desired that the Li represented by x is at least 1.1, 1.15, 1.2 to 1.65, 1.5 or 1.4.

[0060] The cation of the composition may be the metal described, but ideally, at least one metal represented by M is composed of one or more of Ti, Mn, Fe, Co, V, Cr, Ni, and Cu. It may be desirable for M to be composed of Ti and Mn. The composition may be illustratively a composition in which M' is composed of Nb. When Nb is present, it may be desirable for M to be composed of Mn. Illustratively, M' may be Nb and M may be Mn. When Nb and Mn are present or not present with other metals, they may be present in an Mn / Nb ratio of 1 or 2 to 200, 150, 100, 75, 50, 25, or 10 on a molar basis.

[0061] One or more DRPs can be compounds (e.g., metal compounds) consisting of oxygen, fluorine, and one or more P, S, and N, such as oxides, hydroxides, oxynitrides, nitrides, nitrates, sulfides, sulfates, sulfites, phosphates, phosphites, fluorides, and combinations thereof. Examples of precursors may include Mn₂O₃, MnO, LiOH, Nb₂O₅, LiF, NbF₅, and / or the like. For doping oxygen sites with one or more of P, S, and N, at least one precursor includes one of these elements. Possible P, S, and N precursors may include elements P, S, or N, metal nitrides (e.g., lithium nitride), metal nitrates, metal nitrites, metal phosphates, metal phosphides, metal phosphites, metal sulfites, metal sulfates, and metal sulfides (e.g., lithium sulfide), wherein the metal is the metal required in the DR to form the DDR used to manufacture the CP.

[0062] DRP can be dried and mixed in the required amount to achieve the desired DR stoichiometry, or mixed in a liquid such as water or an organic solvent to form a suspension. Mixing can be carried out by any method available to achieve the desired particle size, such as a micro-media mill, ball mill, planetary mill, or grinding mill. The primary particles can have any useful average particle size as described above, with particles up to 2 micrometers, 1 micrometer, 400 nanometers (nm), 200 nm, or 100 nm being useful. An example of a suitable micro-bead mill is the Buhler PML2 mill (Buhler Group).

[0063] If wet mixing is used, the suspension of DRP particles can be dried by any suitable method, such as spray drying, to form secondary particles. Spray drying can be performed using any known commercially available spray dryer, such as a micro spray dryer like the Buchi B-290 model. When using the salt method, the amount of salt must be sufficient to form the desired particle size and morphology as described above without pulverizing the DDR or CP powder. Generally, the DRP / salt weight ratio is approximately from at least 0.5, 0.75, or 1 to 2, 1.75, or 1.5.

[0064] The salt can be any salt that melts at a temperature below the DR synthesis temperature, wherein the salt is ideally melted by 10%, 20%, or 30% to about 50% below the DR synthesis temperature. Examplely, the melting point of the salt is ideally between 400°C or 500°C and 700°C, allowing DR to further feasiblely crystallize below the salt's melting point without causing any substantial growth of particles of the same substance within the solid salt that are not maintained at the crystallization temperature (e.g., an average particle size within 20%, 10%, or 5% by number or volume). The crystallization temperature is typically at least 400°C, 450°C, or 500°C to the salt's melting point.

[0065] In one example, the salting process for forming Mn-containing DRs to be transformed into composite particles can ideally employ disordered rock salt precursors (DRPs). These precursors consist of a disordered rock salt precursor with low solubility in the molten salt (lower solubility DRPs) and a disordered rock salt precursor with higher solubility in the molten salt (higher solubility DRPs). The higher solubility disordered rock salt precursor is composed of Mn or Li, while the lower solubility disordered rock salt precursor does not contain Mn or Li. In a preferred salting process, the lower solubility DRPs are not completely dissolved in the molten salt and serve as nucleation sites for DR formation, thereby forming DDRs. Ideally, the average particle size of the lower solubility DRPs is smaller than that of the higher solubility disordered rock salt precursors.

[0066] The salt can be any useful salt having the aforementioned characteristics, including salts with an atomic radius (van der Waals atomic radius) sufficiently larger than the corresponding ion in the DR used to form the DDR, such that at most trace amounts of the salt ion are present in the DR and the resulting subsequent DDR and CP. Trace amounts are any amount from at most about 10 ppm to the detection limit of known analytical techniques (e.g., parts per billion by weight). Generally, the salt element is at least 10%, 20%, or 30% more abundant than the corresponding Li and O in the DR. Exemplary salts include KBr, KCl, KI, CsBr, CsCl, and any combination thereof.

[0067] The dried DRP particles can then be heated to the DR synthesis temperature. The DR synthesis temperature causes the DRP to react and form a single DR phase. When using the solid-state synthesis method, the DR synthesis temperature is typically 800°C to 900°C, 1100°C, or 1200°C, with a duration of 10 minutes, 1 hour, 2 hours, 3 hours, or 5 hours to 12 hours or 24 hours. When using the salt method, to achieve the desired particle size, particle size distribution, and morphology, the heating rate is ideally as fast as possible, and the time at the DR synthesis temperature is typically 1, 2, 3, or 5 minutes to 30, 15, or 10 minutes.

[0068] The heating rate can be any rate sufficient to achieve the desired particle characteristics of DR, and, illustratively, for the salt process, the heating and cooling rates are advantageously fast enough to achieve the desired particle characteristics without further crushing or grinding the resulting DR. Exemplary salt process heating / cooling rates include at least 10°C / min, 25°C / min, 50°C / min, or 100°C / min to any feasible heating and cooling rate. The rapid heating and cooling rates are the average rates from the salt melting point to the DR synthesis temperature. Rates below the melting point can be any rate, and cooling at a slower rate below the salt melting point or having a temperature that is maintained to improve DR characteristics (e.g., increase crystallinity) without causing undesirable characteristics (e.g., particle growth) may be advantageous. Illustratively, the temperature can be maintained between about 300°C and the melting point of the salt, typically between about 400°C and 600°C.

[0069] DR synthesis can be carried out in any suitable atmosphere, which can be static or flowing. The annealing environment can be under rare gases, nitrogen, atmospheric air, or dry air, or combinations thereof, to achieve the desired partial pressure of one or more gases. In other embodiments, the synthesis conditions can be selected based on the composition of the disordered rock salt precursor, such as the presence of which metals. For example, manganese-based compositions can be produced under the conditions described above (e.g., 750–900 °C for 6 to 24 hours), while compositions based on another metal can have a wider temperature range, a higher range, or a lower range and / or a wider, longer, or shorter time range, or multiple thermal steps.

[0070] After DR is formed, DDR can be formed as described above. In illustrative terms, the salt can be removed from the DR formed by the salting method described herein by dissolving a salt in water, which may include slightly acidic water (pH 1 to below 7) or alkaline water (pH above 7 to 14), and separating the salt by filtration, sedimentation, or centrifugation. The separated powder can then be washed in neutral or alkaline water to produce DDR. Alternatively, DDR can be prepared by heating it to 300°C to 500°C in an oxygen-containing atmosphere (air is suitable). The DDR produced by heating in an oxygen atmosphere can be further washed with neutral or alkaline water (pH > 7 to 14), preferably a lithium hydroxide solution with a pH of at least 10, 10.5, or 11. CP is then formed from the DDR as described above.

[0071] CP can be used to form a cathode by any suitable method, such as those known in the art. For example, CP can be mixed with a binder, such as a polymer that can be used to manufacture a cathode (e.g., a polyfluoropolymer such as polyvinylidene fluoride), and one or more solvents to form a slurry. Non-limiting examples of one or more solvents may be aprotic polar solvents, such as methyl-2-pyrrolidone (NMP). The slurry can then be deposited onto a metal current collector (e.g., stainless steel, copper, or any suitable conductive metal sheet), and the solvent can be removed to form a cathode.

[0072] Ideally, the CP of the cathode has an average secondary particle size of at least 1 to 20 micrometers. Each secondary particle is an aggregate of primary particles. The primary particles of the CP are expected to have the average particle size described herein and may contain other potentially useful particles, such as those that increase conductivity (e.g., carbon or other inorganic highly ionic conductive particles).

[0073] CP cathodes can be used in rechargeable lithium-ion battery cells. A battery cell includes a cathode, anode, separator, and electrolyte. The battery or battery cell can be formed in any suitable atmosphere, such as those common in the art. For example, a high-purity argon atmosphere can be used to limit any undesirable contamination from substances present in the atmosphere.

[0074] Ideally, the CP cathode is also composed of carbon. The formed CP can be mixed with other components that can be used to manufacture the electrode by any method, among which milling as described herein is a suitable method. For example, carbon can be added. Carbon can be added by suspension and spray-dried to form spray-dried particles. Carbon may include acetylene black, carbon black, carbon fibers, graphite, carbon nanotubes, KJ600 and / or the like. Carbon can be mixed in a ratio where CP is majority and carbon precursors are minority. For example, the respective amounts of CP and carbon present can be such that the weight ratio of CP to carbon can be from 100 / 1, 50 / 1, 30 / 1, 20 / 1, or 10 / 1 to 5 / 1, 1.5, or 1 / 1.

[0075] Example Example 1. A method for forming composite particles, comprising: removing lithium from disordered rock salt to form lithium-deficient disordered rock salt; and heating the lithium-deficient disordered rock salt to a transformation time and a transformation temperature to form composite particles having nanodomains of at least one of the disordered rock salt and spinel and monoclinic crystals dispersed therein.

[0076] Example 2. The method as described in Example 1, wherein lithium removal includes one or more of washing disordered rock salt with water and heating it in an oxygen-containing atmosphere to 200°C to 600°C.

[0077] Example 3. The method as described in Example 2, wherein the removal is performed by washing with water in alkaline water.

[0078] Example 4. The method as described in Example 3, wherein the alkaline water is composed of ammonia, alkali metal hydroxide, or a combination thereof dissolved therein.

[0079] Example 5. The method as described in Example 4, wherein the alkaline water comprises one or more of lithium hydroxide and ammonia dissolved therein.

[0080] Example 6. The method as described in Example 2, wherein the removal is performed by heating to 300°C to 500°C.

[0081] Example 7. The method as described in Example 6, wherein the mole fraction of oxygen in the atmosphere is at least 0.1.

[0082] Example 8. The method described in Example 6, wherein the mole fraction of oxygen is at least 0.2.

[0083] Example 9. The method as described in any of the foregoing examples, wherein the average primary particle size of the composite particles is at most 20 micrometers.

[0084] Example 10. The method as described in Example 8, wherein the average primary particle size of the composite particles is 0.1 micrometers to 2 micrometers.

[0085] Example 11. The method as described in Example 9 or 10, wherein the disordered rock salt is disordered rock salt powder with an average particle size within 50% of the average particle size of the composite powder.

[0086] Example 12. The method of any one of the foregoing examples, wherein the disordered rock salt is prepared by reacting a disordered rock salt precursor in a molten salt, the precursor being composed of a disordered rock salt precursor with low solubility in the molten salt and a disordered rock salt precursor with high solubility in the molten salt, wherein the disordered rock salt precursor with high solubility is composed of Mn or Li, and the disordered rock salt precursor with low solubility does not contain Mn and Li.

[0087] Example 13. The method as described in Example 12, wherein the average particle size of the disordered rock salt precursor with lower solubility is smaller than that of the disordered rock salt precursor with higher solubility.

[0088] Example 14. The method as described in any of the foregoing examples, wherein the average particle size of the nanodomains is at most about 20 nm.

[0089] Example 15. The method as described in any of the foregoing examples, wherein heating to the transition temperature and transition time are carried out in an aerobic or anaerobic transition atmosphere.

[0090] Example 16. The method as described in Example 15, wherein the transition atmosphere is an inert gas.

[0091] Example 17. The method as described in Example 15, wherein the transition temperature is 300°C to 600°C and the transition time is at least 30 minutes to 10 hours.

[0092] Example 18. A powder comprising composite particles having dispersed disordered rock salt domains and spinel, monoclinic, or both domains.

[0093] Example 19. The powder as described in Example 18, wherein the average particle size of the domains is at most about 25 nm.

[0094] Example 20. The powder as described in Example 18, wherein the composite particles have a D90 of up to about 1.5 micrometers, a D50 of submicrometer size, and a D10 of at least 0.1 micrometers as primary particles.

[0095] Example 21. The powder as described in any one of Examples 18 to 20, wherein at least 60% of the primary particles by amount have a sphericity of at least 0.65.

[0096] Example 22. A powder as described in any one of Examples 17 to 21, wherein the composite particles have spinel and disordered rock salt that are different in the 200 plane. d spacing.

[0097] Example 23. The powder as described in Example 22, wherein the spinel d The spacing is approximately 0.41 nm, and the disordered rock salt... d The spacing is approximately 0.2 nm.

[0098] Example 24. The powder as described in any one of Examples 18 to 23, wherein the composite particles have a chemical structure represented by the following formula: Li x M' y M z O 2-(a+b) Fa Z b where 1.0 < x < 1.75; 0 ≤ y < 0.55; 0.1 < z < 1; 0 ≤ (a + b) < 0.7; (b ≥ 0); M’ is one of Ti, Ta, Zr, W, Nb or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh and Sb; and Z is one or more of P, N and S.

[0099] Exemplification 25. The powder as described in Exemplification 24, wherein M consists of one or more of Ti, Mn, Fe, Co, V, Cr, Ni and Cu.

[0100] Exemplification 26. The powder as described in Exemplification 25, wherein M consists of Ti and Mn.

[0101] Exemplification 27. The powder as described in Exemplification 24 or 25, wherein M’ consists of Nb and M consists of Mn.

[0102] Exemplification 28. The powder as described in Exemplification 26, wherein the domains consist of monoclinic domains.

[0103] Exemplification 29. The powder as described in Technical Solution 27, wherein the domains consist of spinel domains.

[0104] Exemplification 30. A cathode composed of the powder as described in any one of Exemplifications 18 to 29 and carbon.

[0105] Exemplification 31. A battery composed of the cathode as described in Exemplification 30.

[0106] Exemplification 32. The method as described in any one of Exemplifications 1 to 14, wherein the lithium gradient difference of the lithium-deficient disordered rock salt from its shell to its core is at least 5%.

[0107] Examples Preliminary synthesis of Mn-DR by molten salt method or solid-state method Solid-state method: We first prepare an appropriate amount of powder mixture of precursors such as Li2CO3, Mn2O3, TiO2 / Nb2O5 / , etc. to synthesize Mn-DR compounds using a ball mill (e.g., 500 rpm for 6 hours, using acetone as the ball milling medium or dry milling). Then, the mixed Mn-DR precursors are placed in a crucible and heated at high temperature under Ar (e.g., heated at 1000 °C for 2 hours). After high-temperature solid-state synthesis, the particles are ground by hand grinding or ball milling.

[0108] If the molten salt method is used to produce Mn-DR, in addition to Li2CO3–Mn2O3–TiO2 / Nb2O5 / etc., we also mix other salts, such as CsBr / KBr / NaCl, to prepare the Mn-DR precursor: here, the molten salt flux (e.g., CsBr) helps to form single crystals at low temperatures. We mix all chemicals using specific ball milling conditions (e.g., 500 rpm for 6 hours) in a planetary ball mill. The powder is then collected and dried overnight in a vacuum oven (e.g., at 80°C).

[0109] The dried powder is then placed in a crucible and heated for short periods (e.g., 3, 5, 7, 10, 15 minutes) in a furnace (e.g., a rapid heating furnace) under Ar at temperatures above the melting point of the salt used (e.g., 800°C, 830°C, 850°C, and 900°C). The sample may be further annealed at temperatures below the melting point of the molten salt flux (e.g., 600°C) and held for a certain crystallization time (e.g., 1 to 10 hours), which helps to eliminate possible compositional inhomogeneities in the Mn-DR particles and improve crystallinity.

[0110] Next, once the cured sample has cooled to room temperature, it is removed from the oven, washed with room temperature water or alkaline water (e.g., LiOH solution), and dried overnight in a vacuum oven (e.g., at 80°C).

[0111] A second heating process is performed in air, O2(g), or Ar to induce the formation of composite particles. For Mn-DR particles lacking Li vacancies (lacking chemical gradient) after synthesis in step 1, re-annealing is performed at high temperatures (e.g., 300-500°C) using air or O2(g) to extract Li from the Mn-DR structure upon reaction with the Li in the air or O2(g), forming Li2CO3 or LiOH on the particle surface. Subsequently, the Mn-DR with Li vacancies undergoes nanophase separation at high temperatures to form a DR and spinel nanocomposite material. For Mn-DR particles with Li vacancies after synthesis in step 1, air, O2(g), and Ar can all be used to heat the DDR to high temperatures (e.g., 300-600°C) to directly transform it into nanocomposite particles.

[0112] After heating to induce the formation of composite particles with nanodomains, the CP undergoes a washing step (e.g., with LiOH solution) to remove surface Li₂CO₃ or LiOH from the final compound. Following washing, the sample is dried in a vacuum oven (e.g., at 80°C).

[0113] Figure 1The figures show the Li synthesized using the molten salt method before and after heating to the transformation time and temperature in air and Ar at different temperatures (300℃, 400℃, and 500℃) and holding for 5 hours. 1.2 Mn 0.4 Ti 0.4 XRD pattern of O2 (LMTO), where LMTO was synthesized at 800 °C for 5 min, annealed at 600 °C for 20 h, and washed with deionized water. XRD results show that DR before heating to the transformation temperature has a highly crystalline pure DR phase. Furthermore, XRD results demonstrate how the phase transformation to spinel evolves when heated to different transformation temperatures in Ar and air (indicated by asterisks in the XRD pattern). It also shows that, at the same temperature, the phase transformation in air is more pronounced than that in argon. Heating in air (or O2)... 2(g) During annealing, it is believed that Li vacancies are introduced into Mn-DR as Li is extracted from Mn-DR by air (or O2), forming surface Li2CO3 or LiOH. This, in turn, allows for additional cation rearrangement, leading to the formation of more spinel nanodomains. In principle, Ar re-annealing of Mn-DR without any lithium vacancies (lithium chemigradient) should not result in this spinel formation, but some lithium vacancies are already present in Mn-DR prepared by the salt method, which is thought to be due to Li vacancies occurring during washing in neutral or alkaline water. + -H + Caused by exchange (this Li) + -H + (Exchange level is pH-dependent). SEM images of the original DR material, as well as the material before and after heating to the transition temperature in argon and air, are shown. Figure 2-4 In the middle. These figures show that, with Figures 2 to 3 and Figure 4 In contrast, CP retains its particle size and morphology even after being heated to the transition temperature.

[0114] XRD patterns of solid-state Mn-DR (LMTO) before and after Ar and air annealing are shown in the figure. Figure 5In contrast to molten salt synthesized Mn-DR, Ar-annealed samples did not show a spinel transformation. This is thought to be due to the lack of a sufficient Li gradient during the solid-state synthesis of Mn-DR (e.g., insufficient Li vacancies on the surface), resulting in no incentive for spinel formation during Ar annealing, as there is no incentive to generate surface lithium species (Li₂CO₃, LiOH) through reaction with Ar. This, in turn, simplifies Mn-DR annealing, thereby improving the DR crystal structure. In contrast, when solid LMTO is exposed to air for annealing, Li extraction from the air (forming surface Li₂CO₃, LiOH) generates Li vacancies, triggering the formation of spinel nanodomains. SEM data of air-annealed DR (formed through solid-state synthesis) show signs of surface species formation compared to solid-state prepared Mn-DR. Figure 9 and Figure 10 ,in particular Figure 10 In contrast, Ar heat treatment DR ( Figure 5 , 7 (and 8) did not show spinel formation and slight growth, but retained the morphology of solid-state synthesized Mn-DR. Figure 6 The synthesis state and Figure 7 and 8 (Comparison)

[0115] Figure 11 The cross-section of DDR (LMTO) composite particles formed by the molten salt method is shown. Figure 12 HRTEM images of the cross-section of the composite particles are shown. Figure 13 The image shows a focused ion beam (FIB) cross section of a fast inverse Fourier transform (FFT) flat-field filtered image of the composite particles, revealing disordered rock salt domains (darker areas) and spinel domains (brighter areas) within the composite particles. Figure 14 and 15 The electron diffraction pattern of the composite particles is shown, in which the composite particles show different d-spacings of DR domains (0.201 nm) and spinel domains (0.4121 nm) along the 200 plane.

[0116] Figure 16-18 The voltage distribution of a battery made from disordered rock salt particles produced by the molten salt method and from composite particles made therefrom is shown. Figure 16 In this context, DR (such as) produced by the molten salt method Figure 2 (as shown) and Figure 4 The composite particles are made into batteries using the same materials and methods.

[0117] The particle size of molten salt DR is 500-800 nm. Figure 1The diameter is much larger than that of LMTODRs formed using the solid-state synthesis described herein. Composite particles made from this DR have similar particle sizes ranging from approximately 500 nm to 1 micrometer. Figure 4 The initial discharge capacity of DR is only 53 mAh / g, while the discharge capacity of composite particles formed at 300℃ (LMTO air-annealed at 300℃) is 215 mAh / g, and the discharge capacities of LMTO at -400℃ and -500℃ are both approximately 200 mAh / g. Figure 16 , 17A -C and 18). In nanocomposite structures, a higher spinel ratio (caused by a higher air annealing temperature) results in higher discharge capacity and cycle stability. For example, the discharge capacity of a battery containing LMTO-300℃ composite particles decreased from 215 mAh / g to 170 mAh / g after 30 cycles. Figure 18 In contrast, batteries containing LMTO-400℃ composite particles showed an initial capacity increase to 230 mAh / g during the initial cycle, followed by a gradual decrease to 202 mAh / g after approximately 28 cycles. Similarly, batteries containing LMTO-500℃ composite particles also exhibited an initial capacity increase during both charging and discharging, followed by a decrease in discharge capacity. Figure 18 The use of composite particles in batteries significantly improves performance compared to particles with only disordered rock salt crystal structures. To our knowledge, monocrystalline Mn-DR cathode particles have never achieved a reversible capacity exceeding 200 mAh / g, especially within the particle size range achieved by composite particles with DR and spinel domains.

[0118] Li was produced by the above-mentioned salt method. 1.2 Mn 0.6 Nb 0.2 O2(LMNO)DR was used to form DDR, which was then heated in air (200°C, 300°C, and 400°C) for 5 hours. LMNO was synthesized using NaCl, with a salt-to-precursor ratio of (1:0.5), at 950°C for 5 minutes. After air annealing, Figure 19 The results show that, according to X-ray diffraction (XRD), heating air to 200°C is insufficient to form any detectable spinel, with the XRD pattern showing that spinel forms at 300°C and 400°C (represented as a star shape in the XRD). Figure 20 SEM images of air-annealed LMNO are shown, revealing that the primary particle size of LMNO (composite particles) annealed at 300 and 400 °C is approximately 800 nm to 1000 nm, while the particle size of LMNO annealed at 200 °C is smaller, approximately 500 nm, exhibiting only a DR crystal structure. Figure 19 ). Figure 21 and Figure 22The voltage distributions of batteries using these materials as cathodes are shown (cycled between 1.5–4.8 V at 20 mA / g and 40 mA / g, respectively). Even under high charge-discharge conditions, the reversible capacity of the composite particles (300 and 400 °C) in the single-crystal Mn-DR particles did not reach >200 mAh / g, making our near 250 mAh / g capacity in the 800–1000 nm single-crystal composite particles particularly noteworthy. In summary, the high-capacity composite particles formed from both LMTO and LMNO demonstrate the universality of this invention in manufacturing high-capacity Mn-DR cathode materials without requiring particle size reduction through pulverization to achieve high capacity.

[0119] Figure 23 The diagram illustrates the heating of LMTO prepared via the salt process in air. The top pattern shows an LMTO synthesized at 800°C for 5 minutes, annealed at 600°C for 20 hours, and washed with LiOH solution to remove LMTO from salt heated in air at 300°C for 5 hours. The spinel peaks are clearly visible, as previously shown. Figure 1 As shown in the image. Figure 23 The results show that spinel domains initially form at 300°C and then evolve into a monoclinic phase at temperatures above 400°C, further defined by a peak centered at 21° 2θ as shown in the bottom X-ray pattern, which was obtained by heating at 500°C for 5 hours. The intermediate pattern is LMTO synthesized at 900°C for 20 minutes, annealed at 600°C for 20 hours, and then heated in air at 400°C for 5 hours. The monoclinic peak appears to begin forming, likely due to increased crystallinity at higher synthesis temperatures and times. The heat treatment of LMTO synthesized at 900°C, as described above, shows a more pronounced monoclinic peak at approximately 21° 2θ when heat-treated at 500°C and 600°C for 5 hours.

[0120] Figure 24 The figure shows LMTO particles synthesized at 900°C for 20 minutes, annealed at 600°C for 20 hours, and then heated in air at 300°C for 5 hours. The figure also shows that the particles are significantly larger than, for example... Figure 2-4 The particles shown are synthesized at a lower temperature for a shorter time. Figure 25 The cycling behavior of a battery fabricated using LMTO synthesized at 900°C as described above and heated in air at 500°C for 5 hours is shown. This cycling behavior clearly demonstrates that LMTO with larger grain size and monoclinic domains exhibits good initial capacity, which increases with cycling. Similarly, as... Figure 26As shown, the same material exhibited similar behavior after being heated in air at 600°C for 5 hours, with the initial capacity increasing from approximately 190 mAh / g in the first cycle to approximately 210 to 217 mAh / g in the tenth cycle.

[0121] Figure 27-29 The voltage distribution of LMTO, synthesized at 800°C for 5 minutes, annealed at 600°C for 20 hours, washed with LiOH solution to remove LMTO from the salt, and then heated in air at 300°C, 400°C, and 500°C for 5 hours, as indicated in each figure. Figure 28 and 29 The composite particles showed a monoclinic peak at 21° 2θ in the X-ray diffraction pattern, which is consistent with... Figure 27 Compared to the different distributions shown, they have similar voltage distributions, especially in the 1st and 5th cycles (for batteries containing composite particles showing monoclinic peaks, the capacity increases from the 1st to the 5th cycle).

Claims

1. A method for forming composite particles, comprising: Lithium is removed from disordered rock salt to form lithium-deficient disordered rock salt; The lithium-deficient disordered rock salt is heated to a transformation time and a transformation temperature to form composite particles having nanodomains of at least one of the disordered rock salt and spinel and monoclinic crystals dispersed therein.

2. The method of claim 1, wherein the lithium removal comprises one or more of washing the disordered rock salt with water and heating it in an oxygen-containing atmosphere to 200°C to 600°C.

3. The method of claim 2, wherein the removal is performed by washing in alkaline water.

4. The method of claim 3, wherein the alkaline water is composed of ammonia, alkali metal hydroxide or a combination thereof dissolved therein.

5. The method of claim 4, wherein the alkaline water comprises one or more of lithium hydroxide and ammonia dissolved therein.

6. The method of claim 2, wherein the removal is performed by heating to 300°C to 500°C.

7. The method of claim 6, wherein the mole fraction of oxygen in the atmosphere is at least 0.

1.

8. The method of claim 6, wherein the mole fraction of oxygen is at least 0.

2.

9. The method of claim 1, wherein the average primary particle size of the composite particles is at most 20 micrometers.

10. The method of claim 9, wherein the average primary particle size of the composite particles is 0.1 micrometers to 2 micrometers.

11. The method of 10, wherein the disordered rock salt is disordered rock salt powder having an average particle size within 50% of the average particle size of the composite particles.

12. The method of claim 1, wherein the disordered rock salt is prepared by reacting a disordered rock salt precursor in molten salt, the precursor being composed of a disordered rock salt precursor with low solubility in molten salt and a disordered rock salt precursor with high solubility in molten salt, wherein the disordered rock salt precursor with high solubility is composed of Mn or Li, and the disordered rock salt precursor with low solubility does not contain Mn and Li.

13. The method of claim 12, wherein the average particle size of the disordered rock salt precursor with lower solubility is smaller than the particle size of the disordered rock salt precursor with higher solubility.

14. The method of claim 1, wherein the average particle size of the nanodomains is at most about 20 nm.

15. The method of claim 1, wherein the heating to the transition temperature and the transition time are carried out in an aerobic or anaerobic transition atmosphere.

16. The method of claim 15, wherein the transition atmosphere is an inert gas.

17. The method of claim 15, wherein the transition temperature is 300°C to 600°C and the transition time is at least 30 minutes to 10 hours.

18. A powder comprising composite particles having dispersed disordered rock salt domains and spinel, monoclinic, or both domains.

19. The powder of claim 18, wherein the average particle size of the domains is at most about 25 nm.

20. The powder according to claim 18, wherein the composite particles have primary particles with a D90 of at most about 1.5 micrometers, a D50 in the submicrometer range, and a D10 of at least 0.1 micrometer.

21. The powder according to claim 18, wherein at least 60% by number of the primary particles have a circularity of at least 0.

65.

22. The powder of claim 18, wherein the composite particles have different spinels and disordered rock salts on the 200 plane of the composite particles. d spacing.

23. The powder of claim 22, wherein the spinel d The spacing is approximately 0.41 nm, and the disordered rock salt... d The spacing is approximately 0.2 nm.

24. The powder according to claim 18, wherein the composite particles have a chemical structure represented by the following formula: Li x M' y M z O 2-(a+b) F a Z b where 1.0 < x < 1.75; 0 ≤ y < 0.55; 0.1 < z < 1; 0 ≤ (a + b) < 0.7; (b ≥ 0); M' is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, and Sb; and Z is one or more of P, N, and S.

25. The powder according to claim 24, wherein M is composed of one or more of Ti, Mn, Fe, Co, V, Cr, Ni, and Cu.

26. The powder according to claim 25, wherein M is composed of Ti and Mn.

27. The powder according to claim 25, wherein M' is composed of Nb and M is composed of Mn.

28. The powder according to claim 26, wherein the domains are composed of monoclinic domains.

29. The powder according to claim 27, wherein the domains are composed of spinel domains.

30. A cathode comprising the powder according to claim 18 and carbon.

31. A battery comprising the cathode according to claim 30.

32. The method according to claim 1, wherein the lithium gradient difference of the lithium-deficient disordered rock salt from its shell to its core is at least 5%.

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