Disordered rocksalt material and method of forming it

Abstract

A disordered rocksalt powder comprised of submicrometer primary particles without asperities arising from pulverization may be made by heating, at an average heating rate, disordered rocksalt precursors in a salt to a reaction temperature above the salt's melting point for a reaction time to form the disordered rocksalt powder in the salt, cooling, the disordered rocksalt powder and salt to below the salt's melting point at an average cooling rate, and separating the disordered rocksalt powder from the salt, the average heating and cooling rate being at least 5 ? / min when heating between the salt's melting point to the reaction temperature.

Description

DISORDERED ROCKSALT MATERIAL AND METHOD OF FORMING ITFIELD

[0001] The present invention is in the field of battery technology.BACKGROUND

[0002] Lithium metal oxides have been used to formulate cathode materials for lithium ion batteries. The cathodes arc derived from a few basic crystallographic structure types, such as spinels, olivines, and layered oxide structures. The layered oxide structures have included lithium- excess type structures, where additional lithium is present in the structure.

[0003] Recently, attention has been focused on disordered rocksalt structures, such as those formed from particular lithium metal oxides. Compounds represented by the formula: xLi3NbO4’(l-x)LiMO2(1) where M is a divalent or trivalent cation, have been shown to be a promising class of transition metal oxides for use as cathodes in lithium ion batteries. The compounds of formula (1) are considered a disordered rocksalt in which a random atomic arrangement of lithium and transition metal ions are packed in a closely-packed cubic structure. These disordered rocksalt compositions offer the ability to contain up to 3 lithium atoms per formula unit, which is more than the conventional lithium-excess layered materials. Formula (1) can be transformed and represented as LixMyNzOw.[00041 The disordered rocksalt structure is an attractive cathode material for next generation lithium ion batteries due to a greater specific energy density (e.g., a higher theoretical energy density) than state-of-the-art cathode materials, such as layered lithium metal oxide structures. For example, certain disordered rocksalt structure materials have a theoretical gravimetric energy density of about 1120 Wh / kg, while a LiMii2O4 active material has a theoretical gravimetric energy density of about 492 Wh / kg and a LiMn1.5Nio.5O4 has a theoretical gravimetric energy density of about 691 Wh / kg. This energy density is especially appealing when lower cost raw materials are used as components in the disordered rocksalt structure, such as manganese, which may be incombination with other transition metals. As such, the disordered rocksalt (DR) materials can achieve relatively high energy density with relatively low material cost. In order to achieve comparable energy density, known cathode materials require higher-cost raw materials, such as cobalt or nickel.

[0005] Unfortunately, these DR materials require the particle size to be in the submicrometer range due to the low Li diffusivity of these materials. This has caused these DR materials to suffer poor capacity and voltage retention issues, largely originating from the poorly controlled, heavily- pulverized nanoparticle morphology introduced upon preparing the DR materials. The pulverized particle morphology of Mn-DR tends to accelerate the electrolyte decomposition and Mn- dissolution to the electrolyte, leading to the short cycle life of the cathode materials. Also, the pulverized particle morphology may lead to low electrode density decreasing the volumetric energy density of the Mn-DR cathode film.

[0006] Accordingly, it would be desirable to provide DR materials that avoid one or more of the problems of the prior art as described above and batteries comprised of disordered rocksalt. In particular, it would be desirable to provide a method and DR particles that are submicrometer in size without pulverization or greatly reduced pulverization.BRIEF SUMMARY

[0007] We have discovered a method of forming disordered rocksalt (DR) particles that avoids the angular asperities arising from mechanical pulverization of the DR and wide particle size distribution of particles having fractions of particles that may have high surface energies tending to exacerbate dissolution of Mn compromising battery cell life. The method involves the rapid heating and cooling of DR precursors in the presence of a sufficient amount of a substantially non- reactive liquid that at least partially dissolves one or more of the precursors at the reaction temperature and at least one precursor that essentially does not dissolve completely and may act as a nucleator site to form submicron spheroidal DR primary particles with a narrow particle size distribution in the substantial absence of hard agglomerates. Hard agglomerates, herein, are primary particles sintered by ionic or covalent bonds to form secondary particles generally requiring attrition to the primary particles. Soft agglomerates are primary particles that arecoalesced by bonding that may be disrupted merely by shearing in a liquid such as hydrogen and van der Waals bonding.

[0008] An illustration is a method to form a disordered rocksalt (DR) powder comprising, heating, at an average heating rate, disordered rocksalt precursors in a salt to a reaction temperature above the salt’s melting point for a reaction time to form the disordered rocksalt powder in the salt, cooling, the disordered rocksalt powder and salt to below the salt’s melting point at an average cooling rate, and separating the disordered rocksalt powder from the salt, the average heating rate and cooling rate being at least 5 °C / min when heating between the salt’s melting point to the reaction temperature. It has been discovered that submicrometer disordered rocksalt powders may be made by employing a molten salt and rapid heating and cooling from the melting point of the salt or onset of the reaction to form the disordered rocksalt powder to the reaction temperature used to form the DR powder.

[0009] Another illustration is a powder comprised of disordered rocksalt primary particles having a maximum primary particle size of at most 2 micrometers and at least 60% of the primary particles by number have a circularity of at least 0.65. That is, the DR powders lack asperities present in milled DR powders. The disordered rocksalt powder may be comprised of a trace amount of K, Cs, Br and Cl. Trace herein is an amount that is detectable by known bulk analysis techniques such as inductively coupled plasma mass spectrometry. A trace is any amount from 100, 10, or 1 part per million by weight to the detectable limit.

[0010] The DR powder may be used in primary and secondary batteries lithium ion batteries. The DR powder may be used with any suitable electrolyte, separator and anode such as those known in the art.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a scanning electron micrograph (SEM) of disordered rock salt particles not of this invention.

[0012] Figure 2 shows the X-ray diffraction (XRD) patterns of disordered rock salt particles not of this invention.

[0013] Figure 3 is a scanning electron micrograph of DR powder of this invention.

[0014] Figure 4 shows the X-ray diffraction pattern of a disordered rocksalt powder of this invention.

[0015] Figure 5 is a scanning electron micrograph of DR powder of this invention.

[0016] Figure 6 shows the X-ray diffraction pattern of a disordered rocksalt powder of this invention.

[0017] Figure 7 shows the X-ray diffraction pattern of a disordered rocksalt powder of this invention

[0018] Figure 8 is a scanning transmission electron micrograph and electron energy loss spectroscopy (EELS) elemental analysis of a disordered rock salt powder of this invention.

[0019] Figure 9 is a scanning transmission electron micrograph and electron energy loss spectroscopy (EELS) elemental analysis of a disordered rock salt powder of this invention.

[0020] Figure 10 is a scanning electron micrograph of DR of this invention prior to annealing the DR.

[0021] Figure 11 is a scanning electron micrograph of DR of this invention after annealing.

[0022] Figure 12 shows the particle size of the DR of this invention prior to and after annealing.

[0023] Figure 13 are plots showing the specific capacity v. voltage and discharge capacity of electrodes of this invention using differing DRs of the invention.

[0024] Figure 14 are plots showing the specific capacity v. voltage and discharge capacity of electrodes of this invention using differing DRs of the invention.

[0025] Figure 15 arc plots showing the specific capacity v. voltage and discharge capacity of electrodes of this invention using differing DRs of the invention.

[0026] Figure 16 is a plot of specific capacity v. cycle number of electrodes made from DR of and not of this invention.

[0027] Figure 17 shows differential capacity v. voltage plots electrodes made from DR not of this invention for differing cycles.

[0028] Figure 18 shows differential capacity v. voltage plots electrodes made from DR of this invention for differing cycles.

[0029] Figure 19 shows the average V v. cycle number for electrodes made from DR of and not of this invention.

[0030] Figure 20 shows two scanning electron micrographs at differing magnifications of a cross-section of an electrode made using DR not of this invention prior to cycling.

[0031] Figure 21 shows two scanning electron micrographs at differing magnifications of a cross-section of an electrode made using DR not of this invention after 40 cycles.

[0032] Figure 22 shows two scanning electron micrographs at differing magnifications of a cross-section of an electrode made using DR of this invention prior to cycling.

[0033] Figure 23 shows two scanning electron micrographs at differing magnifications of a cross-section of an electrode made using DR of this invention after 40 cycles.

[0034] Figure 24 shows X-ray diffraction plots of DR not of this invention prior to cycling and after battery cycling.

[0035] Figure 25 shows X-ray diffraction plots of DR of this invention prior to cycling and after battery cycling.

[0036] Fiugre 26 shows an X-ray diffraction pattern of DR particles of this invention.

[0037] Figure 27 is an SEM of DR particles of this invention.DETAILED DESCRIPTION

[0038] The following definitions apply to some of the aspects described with respect to some embodiments of the invention. These definitions may likewise be expanded upon herein. Each term is further explained and exemplified throughout the description, figures, and examples. Any interpretation of the terms in this description should take into account the full description, figures, and examples presented herein.

[0039] The singular terms “a,” “an,” and “the” include the plural unless the context clearly dictates otherwise. Thus, for example, reference to an object can include multiple objects unless the context clearly dictates otherwise.

[0040] A rate “C” refers to either (depending on context) the discharge current as a fraction or multiple relative to a “1 C” current value under which a battery (in a substantially fully charged state) would substantially fully discharge in one hour, or the charge current as a fraction or multiple relative to a “1 C” current value under which the battery (in a substantially fully discharged state) would substantially fully charge in one hour.

[0041] To the extent certain battery characteristics can vary with temperature, such characteristics are specified at about 20 to about 30 degrees C, unless the context clearly dictates otherwise.

[0042] Ranges presented herein are inclusive of their endpoints. Thus, for example, the range 1 to 3 includes the values 1 and 3 as well as the intermediate values. When a majority is specified of a component, it means more than 50% by mole or (readily understood from the context used) to essentially all of that component (99% or less). That is, the majority specified constituent of a component is present in an amount greater than 50% to 99%, 90, 80%, 70% or 60% of that component. When a minority of a component is a specified constituent, it is present in an amount less than 50% to about 1% with the balance being the majority specified constituent unless otherwise specified.

[0043] The DR powder and morphology and particle size and distribution are useful in formulating electrodes of electrochemical cells. The DR powder may be used to form a cathode useful in a lithium ion battery. The lithium ion battery includes an electrolyte formulation with alithium salt present at a concentration suitable for conducting the lithium ions through the electrolyte formulation between the cathode and an anode during the discharge and recharge of the battery.

[0044] Pulverization of large particles of synthesized DR to less than 100 nm is commonly used to realize the necessary battery characteristics to be commercially viable. The discovered method realizes DR powder that arc submicromctcr without the use of pulverization (lacks asperities). By the process, a powder that comprises unagglomerated disordered rocksalt primary particles having a maximum particle size of at most 2 micrometers and at least 60% of the primary particles by number have a circularity of at least 0.65 may be produced. The circularity indicative of a particle not formed by pulverization.

[0045] An individual particle circularity is defined as the 4TTA / P2, where A is the area of the particle and P is the perimeter length of the particle, both as viewed from a random perspective. Sphericity, a related parameter, is derived as the square root of circularity. Circularity is a numerical value greater than zero and less than or equal to one. A perfectly circular particle is referred to as having a circularity of 1.00. Tables of population circularity data are represented in such a way that various levels of circularity (e.g., 0.65, 0.75, 0.85, 0.90, and 0.95) are accompanied by percentages of the particle sample population with a circularity greater than the tabulated value. Particle size and shape can be measured by any suitable methods known in the art to measure particle size by diameter. In some embodiments, the particle size and shape are determined by laser diffraction as is known in the art. For example, particle size can be determined using a laser diffractometer such as the Microtrac S3500 with static image analysis accessory using PartAnSI software to analyze the captured images of the particles or image analysis of scanning electron micrographs of the DR powder (e.g., counting of at least 100 particles by image analysis software such as described above). Desirably, at least about 70%, 75% or 80% of the particles (by number) have a circularity that is at least about 0.65, 0.75, 0.8 or 0.85 (i.e., spherical as used herein).

[0046] The DR powder has a maximum size (Dioo) of at most 2 micrometers. Typical DRs generally have a particle size that is substantially less than 100 nm (average less than or D90 of less than 100 nanometers equivalent spherical diameter by volume or number). It has been discovered that CPs having particles from 100 nm to 2 micrometers in contrast to typical DRs may have useful battery characteristics with a particle distribution by number or volume of a D90 of atmost about 1.5 micrometers, D50 that is submicrometer (e.g., less than 1 micrometer to about 0.1 micrometer), and a Dio of at least 0.02, 0.05 or 1 micrometer being particularly useful. The DR powders desirably have a narrow size distribution such as one having a D90 / D10 ratio of at most 5, 4, 3, or 2 to above 1.

[0047] The primary particles of the DR powder may be agglomerated to form aggregates (secondary particles such as those arising from spray drying, which may be further sintered if desired). Primary particles are discrete unagglomerated particles preferably having the aforementioned particle size distribution. Unagglomerated particles are those that may easily be disrupted by shear (e.g., those bonded by van der Waals or hydrogen bonding).

[0048] The DR powder primary particles may display a structural difference within the particle such as elemental gradients shown by energy dispersive spectroscopy (EDS) or electron energy loss spectroscopy (EELS). The powder may display elemental uniformity. Uniformity is when each element is within 5% throughout the particle of the average concentration as determined by EDS or EELS. Above this limit, the particle has an elemental gradient. The presence of a gradient may be shown by electron microscopy showing elemental concentration by color gradation set by a filter.

[0049] The DR powder may be any disordered rocksalt composition useful to make a battery. Exemplary DR composition for the DR powder may be a DR comprising one having a formula:LixM’ yM / CL-ta+bjFa Zb where 1.0<x<1.75; 0<y<0.55; 0.1<z<l; 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. Further dopants may be included such as those substituting for Li such as Na and Mg, which may be at any useful amount, but generally are at most about 10% or 5% to 0.01% by mole of the lithium and such dopants present in the DR.

[0050] The amount of F and Z may be a majority or minority of the anion (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 may be any combination of P, N and S, or may be just one of them. The ratio between P, N and S when two or more are present may be any useful ratio depending on theattributes sought. For example, it may be desirable to have S present when a reduced redox potential is desired. It may also be desirable for S to be the majority of the P, S and N present in the composition.

[0051] The composition may have any desirable Li of 1 or above, but it may be desirable for Li as represented by x to be at least 1.1, 1.15, 1.2 to 1.65, 1.5 or 1.4.

[0052] The cation of the composition may be the metals described, but desirably, at least one of the metals as represented by M is comprised of one or more of Ti, Mn, Fe, Co,V, Cr, Ni and Cu. It may be desirable for M to be comprised of Ti and Mn. The composition may illustratively be one where M’ is comprised of Nb. When Nb is present, it may be desirable for M to be comprised of Mn. Illustratively, M’ may be Nb and M may be Mn. When Nb and Mn are present with or without other metals, they may be present in a ratio of Mn / Nb of 1 or 2 to 200, 150, 100, 75, 50, 25 or 10 by mole.

[0053] The method comprises heating and cooling disordered rocksalt precursors (DRPs) and a salt to a reaction temperature above the salt’s melting point with sufficient rapidity and brevity at the reaction temperature to form the disordered rocksalt powder. Illustratively, the average cooling and heating rate, even though 5 °C / min may be sufficient, desirably the average rate for either or both is at least 10 °C / min, 20 °C / min, 50 °C / min, 1 °C / second (s), 2 °C / s or even 5°C / s to any practicable amount that does not result in thermal shock to the heating furnace or containers used to cany out the method. The average heating rate and cooling rate is the average rate from the salts melting temperature to the reaction temperature. The rate below the melting temperature may be any rate and it may be advantageous to cool below the salt melting point at slower rates or have a hold temperature to improve a DR characteristic such as increasing the crystallinity, without causing undcsircd characteristics (c.g., particle growth or sintering of primary particles). Illustratively, the temperature may be held at a temperature from about 300 °C to the melting point of the salt and typically is from about 400 °C to 600 °C. The time at.

[0054] DRP / salt volume or weight ratio should be sufficient to form the unagglomerated DR powder, with the ratio being at least 0.1, 0.25, 0.5, 0.75 to 2 or 3 or any practicable amount. The ratio is believed, without being limiting, desirable in limiting the solid state reactions that mayoccur prior to salt’s melting as well as having a sufficient amount of salt to dissolve one or more of the DRPs sufficiently to realize the unagglomerated DR powder.

[0055] The salt may preferentially dissolve one or more of the DRPs under the heating conditions. That is, Applicant has discovered that at the reaction temperature heterogeneous nucleation may be used to reduce the average particle size of the DR. The DRs formed under heterogeneous nucleation may be blended with those formed under homogeneous nucleation. For example, compounds comprised of Li or Mn have been found to be useful for heterogenous nucleation. The selection of the salt or combination of salts may be used to vary the solubility to realize the unagglomerated DR powder. The solubility of the DRP in the salt may be determined by solubility determinations of the DRP without other DRPs in the salt by known techniques such as EDS of cooled samples.

[0056] In an illustration, the salt and each DRP are a powder. To facilitate the formation of desired DR powder, each of these precursor powders are of a similar particle size and size distribution that are uniformly distributed in a precursor mixture (random 10 samples have a ratio of salt / DRP that are within 20%, 10%, 5%, 2% or 1%). Similar particle size meaning that the average particle size of each of these powders are within an order of magnitude or each other. Generally, the salt and DRPs powders have an average size of at most about 20 micrometers, 15, micrometers, 10 micrometers, 5 micrometers or 2 micrometers to at least about 0.1 micrometers.

[0057] One or more of the DRPs may be compounds (e.g., metal compound) comprised 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 Li2COa, M112O-,, TiOa, NbsOs. Mn Oa, MnO, LiOH, Nb Os, LiF, NbFs, and / or the like. For doping the oxygen site 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 elemental P, S or N, metal nitrides (e.g. lithium nitride), metal nitrates, metal nitrites, metal phosphates, metal phosphides, metal phosphites, metal sulfites, metal sulfates, metal sulfides (e.g., lithium sulfide), wherein the metal is one that is desired in the DR such as described above.

[0058] DR powder may be comprised of micro-sized aggregates of primary particles, which may be useful to increase the capacity and energy density of a battery cathode. The aggregates arereferred to herein as secondary particles or aggregates. The secondary particles desirably have average particle sizes (e.g., diameters) in the micrometer scale, such as between 1 micrometer and 20 micrometers. The terms “primary” and “secondary” indicate that the primary particles are formed before the secondary particles, and the secondary particles are agglomerations of the primary particles. The primary particles have average particle sizes (e.g., diameters) in the nanometer scale, such as described above. The secondary particles of the disordered rocksalt powder may yield desirable characteristics such as high electrode energy density and may incorporate other useful additives.

[0059] The DRPs and salt may be mixed dry, at the desired amounts to realize the desired DR stoichiometry, or in a liquid such as water or organic solvent to make a suspension. The mixing may be performed by any method useful to realize the desired particle size with examples being a micromedia mill, ball mill, planetary mill or attrition mill. The primary particles may have any useful average particle size as previously described with particles of at most 2 micrometer, 1 micrometer, 400 nanometers (nm), 200 nm, or 100 nm being useful. An Example of a suitable micro bead mill is a Buhler PML2 mill (Buhler Group). Desirable organic solvents are those that do not dissolve the DRPs and salt to any great extent (less than 10% by mass of the DRPs and salt are dissolved).

[0060] The suspension of DRP particles and salt may then be dried, if wet mixed, by any suitable method.

[0061] The salt may be any that melts at a temperature below the DR reaction temperature with the salt desirably melting 10%, 20% or 30% to about 50% below the DR reaction temperature. Illustratively, the salt desirably has a melting temperature from 400 °C or 500 °C to 700 °C, allowing for the further practicable crystallization of the DR below the salt’ s melting point without any substantial growth of the particles (e.g., average size is within 20%, 10% or 5% by number or volume) of the same material not held at crystallization temperature within the solid salt. The crystallization temperature generally is at least 400 °C, 450 °C, or 500 °C to below the melting point of the salt.

[0062] In an illustration, particularly to form Mn containing DRs disordered rocksalt precursors (DRPs) are desirably comprised of a disordered rocksalt precursor having a lowersolubility (lower solubility DRP) and disordered rocksalt precursors having a higher solubility (higher solubility DRP) in the salt in its molten state. The disordered rocksalt precursors having higher solubility desirably are comprised of Mn or Li and the disordered rocksalt precursors having lower solubility are in the absence of Mn and Li. Preferably the lower solubility DRP are not fully dissolved in the molten salt and act as nucleation sites for the formation of the DR. Desirably, the lower solubility DRPs have an average particle size that is less than the higher solubility disordered rocksalt precursors’ particle size.

[0063] The salt may be any useful salt having the aforementioned characteristics including those having an ionic atomic radius (van der Waals atomic radii) sufficiently larger than the corresponding ion (e.g., Li v. K and Cs and O v. Br and 1) in the DR most a trace amount of salt ion is present in the DR. Trace is any amount of at most about 10 ppm to the detectability limits by known analytical techniques (e.g., 1 part per billion by weight). Generally, the salt elements are at least 10%, 20% or 30% larger than the corresponding Li and O in the DR. Exemplary salts include KBr, KC1, KI, CsBr, CsCl, CsI and any combination thereof. Cs salts are preferred in that DR synthesize with Cs salts tend to form higher purity DRs.

[0064] The DRP particles and salt may then be heated to the reaction temperature for the reaction time. The DR synthesis temperature causes the DRPs to react and form a DR powder. The DR reaction temperature generally is from 750 °C or 800 °C or 900 °C to 1000 °C, 1100 °C or 1200 °C for a time that is desirably as rapid as possible and the time at the DR reaction temperature is generally from 1 second, 30 seconds, 1 minute, 2 minutes or 5 minutes to 30 minutes, 15 minutes or 10 minutes.

[0065] A further annealing to induce one or more desirable characteristics such as uniformly distributing the elements of the composition (i.c., increase the crystallinity or uniformity of the crystalline phase of the particles) below the melting point of the salt may be performed as described above. Desirably, prior to separating the salt from the DR powder, the disordered rocksalt powder may be cooled from the reaction temperature to an annealing temperature below the salt’s melting point to a temperature capable of practicable diffusion of elements within the DR to improve one or more characteristics. Typically, the annealing temperature is from 300 °C, 400 °C, 500 °C to 700 °C, 650 °C, or 630 °C. The annealing time may be any that realizes the desired characteristics without unduly causing undesired characteristics such as particle growth and formation of hardagglomerates. Generally useful annealing time are from 10 minutes or 30 minutes to 10 hours, 5 hours or 1 hour. The annealing may also occur after the DR has been washed and separated (e.g., washed with DIW water). The annealing may also occur after immersing the washed DR in a lithium containing solution such as an aqueous lithium solution to adjust the stoichiometry and then annealing using a salt described at DR / salt ratios akin to the DRP / salt ratios.

[0066] DR powder may be separated after cooling the molten salt and DR powder by any suitable method such as aqueous washing and filtering, which may be basic or acidic (i.e., pH 1 to 14 with deionized water being an example). After the washing and separation, the DR powder may be immersed in a lithium solution (e.g., lithium hydroxide solution) to replace any loss of lithium arising from washing to remove the salt. The concentration of the lithium solution may be any useful with concentrations such as a pH of 10, 11 to a saturated solution being exemplary. The DR powder may be separated by one or more filtration and washing steps to realize the desired stoichiometry. The immersion time and temperature may be any suitable with 5 minutes to 8 hours and 10 °C to 50 °C being exemplary.

[0067] The DR powder may be used to form a cathode by any suitable method such as those known in the art. For example, the DR powder may be mixed with a binder such a polymer useful to make cathodes (e.g., polyfluoropolymer such as polyvinylidene fluoride) and one or more solvents to form a slurry. Non-limiting examples of the one or more solvents may be an aprotic polar solvent such as methyl-2-pyrrolidinone (NMP). The slurry may then be deposited on a metal current collector (e.g., stainless steel, copper, or any suitable conductive metal thin) and the solvent removed to form the cathode.

[0068] Desirably the DR of the cathode has an average secondary particle size of 1 to 20 micrometers. Each of the secondary particles is an aggregate of primary particles. The DR primary particles desirably have an average particle size as described herein and may contain other particles that may be useful such as increasing the electrical conductivity (e.g., carbon or other inorganic high ionic conductive particles).

[0069] The DR cathode may be used in a rechargeable lithium ion battery cell. The battery cell includes the cathode, an anode, separator and electrolyte. The battery or battery cell may be formed in any suitable atmosphere such as common in the art. For example, a high purity argonatmosphere may be used to limit any undesirable contamination from species present in atmospheric air.Illustrations

[0070] Mn containing DR powders (Mn-DR powders) are formed from DRPs (e.g., IJ2CO3, M Ch, TiCh, NbiOs, LiF) that are mixed with salt or a mixture of salts with an acceptably low melting point (e.g., KBr, KC1, KI, CsBr, CsCl) such as by using a planetary ball-milling machine (e.g., 6 hours at 500 rpm). Here, the precursors and salt can be mixed with different weight ratios (e.g., precursor: salt = 1:1.5 by weight). Also, a ball milling medium can be introduced in this step, such as acetone that may be removed by simple evaporation. The DRP-salt powder mixture is dried in the oven at 60°C for several hours after removal of solvent if present.

[0071] This dried mixture is then placed in a Quartz shuttle tube furnace and heated to a reaction temperature for short times (e.g., 3, 5, 7, 10, 15 minutes) at a temperature slightly above the salt’s melting point (such as 800 °C, 830 °C, 870 °C, and 900 °C): During this process, rapid heating / annealing (such as with a rapid annealing furnace or spark plasma sintering and microwave heating) may be used for raising temperature from room temperature to the target synthesis temperature (e.g., 1 °C / s), which produces small Mn-DR unagglomerated particles. The small unagglomerated particles is believed to arise, without being limiting, from phase nucleation that may be from insoluble DRPs at the reaction temperature or the short time, while limiting the growth of the particle at the reaction temperature by the presence of a sufficient amount of salt.

[0072] Depending on the reaction conditions, the DR powder formed if having the desired uniformity is washed with cold or warm water or with a diluted acid solution to remove the salt from the Mn-DR powder with deionized water being useful. After the washing, the Mn-DR powder may be dried in a vacuum oven.

[0073] The Mn-DR powder mixed with solidified salt may go through an annealing process (Mn-DR together with the solidified salt) at a temperature below the melting point of the salt (e.g., 600oC for 10 hours when using CsBr) to form the desired DR powder. This annealing step may be used to improve the particle crystallinity while limiting the particle growth due to the existence of solidified salt acting as the physical barrier against particle growth and sintering. After theannealing step, the mixed Mn-DR and salt powder are washed using water or a diluted basic solution several times to remove the salt, leaving Mn-DR as the remaining powder. Then, the Mn- DR powder is dried in a vacuum oven overnight, such as at 80 °C.Illustrations

[0074] Illustration 1. A method to form a disordered rocksalt powder comprising, heating, at an average heating rate, disordered rocksalt precursors in a salt to a reaction temperature above the salt’s melting point for a reaction time to form the disordered rocksalt powder in the salt, cooling, the disordered rocksalt powder and salt to below the salt’s melting point at an average cooling rate, and separating the disordered rocksalt powder from the salt, the average heating and cooling rate being at least 5 °C / min when heating between the salt’s melting point to the reaction temperature.

[0075] Illustration 2. The method of illustration 1 , wherein the disordered rocksalt powder and salt are present in a weight ratio of at least 0.25

[0076] Illustration 3. The method of either illustration 1 or 2, wherein the salt has a cation radius that is at least 1.2 times greater than lithium’s cationic radius.

[0077] Illustration 4. The method of any one of the preceding illustrations, wherein the salt’s melting point is at least 400 °C to 800 °C.

[0078] Illustration 5. The method of any one of the preceding illustrations, wherein the salt is comprised of one or more of KBr, KC1, KI, CsBr, CsCl.

[0079] Illustration 6. The method of any one of the preceding illustrations, wherein the average cooling rate is at least 1 °C / second between the salt’s melting point to the reaction temperature.

[0080] Illustration 7. The method of any one of the preceding illustrations, wherein the reaction time is at most 60 minutes at the reaction temperature.

[0081] Illustration 8. The method of any one of the preceding illustrations, wherein the disordered rocksalt powder is comprised of primary particles having an average particle size of atmost 2 micrometers equivalent spherical diameter and at least 65% of the primary particles have a circularity of at least 0.65.

[0082] Illustration 9. The method of any one of the preceding illustrations, wherein the salt and the disordered rocksalt precursors are each a powder having an average particle size of less than 20 micrometers.

[0083] Illustration 10. The method of any one of the preceding illustrations, wherein the disordered rocksalt precursors have differing solubilities in the salt at the reaction temperature and reaction time.

[0084] Illustration 11. The method of illustration 10, wherein disordered rocksalt precursors having a lower solubility are incompletely dissolved in the salt at the reaction temperature.

[0085] Illustration 12. The method of any one of the preceding illustrations further comprising, prior to separating, annealing the salt and the disordered rock salt powder at an annealing temperature that is at least 300 °C to below the salt’s melting point.

[0086] Illustration 13. The method of illustration 12, wherein the annealing is at an annealing temperature of 500 °C to 800 °C for an annealing time of at most 24 hours.

[0087] Illustration 14. The method of any one of the preceding illustrations, wherein the cooling has an average cooling rate of at least 10 °C / minute when cooling from the reaction temperature to the salt’s melting point.

[0088] Illustration 15. A powder comprised of unagglomerated disordered rocksalt primary particles having a maximum particle size of at most 2 micrometers and at least 60% of the primary particles by number have a circularity of at least 0.65

[0089] Illustration 16. The powder of illustration 15, wherein at least 70% of the primary particles by number have a circularity of at least 0.8.

[0090] Illustration 17. The powder of either of illustration 15 or 16, wherein the primary particles have a D90 of at most about 1.5 micrometers, D50 that is submicrometer, and a D10 of at least 0.1 micrometer.

[0091] Illustration 18. The powder of any one of illustration 15 to 17, wherein the disordered rocksalt powder has a trace amount of one or more of K, Cs, Br and Cl.

[0092] Illustration 19. The powder of any one of illustrations 15 to 18, wherein the disordered rocksalt powder has a chemistry represented byLixM’yMzO2-(a+b)FaZb where 1.0<x<1.75; 0<y<0.55; 0.1<z<l; 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.

[0093] Illustration 20. The powder of illustration 19, wherein M is comprised of one or more of Ti, Mn, Fe, Co,V, Cr, Ni and Cu.

[0094] Illustration 21. The powder of illustration 20, wherein M is comprised of Ti andMn.

[0095] Illustration 22. The powder of any one of illustrations 19 to 21, wherein M’ is comprised of Nb.

[0096] Illustration 23. A cathode comprised of the powder of any one of illustrations 15 to22 and carbon.

[0097] Illustration 24. The method of any one of illustrations 1 to 14, wherein the salt is removed by washing with water and separating to form a washed disordered rocksalt powder.

[0098] Illustration 25. The method of illustration 24, where the water has a pH of 6 to 8.

[0099] Illustration 26. The method of illustration 25, wherein the water has been deionized.

[0100] Illustration 27. The method of illustration any one of illustrations 24 to 26, wherein the washed disordered rocksalt powder is immersed in a solution comprised of Li to form a Li reinserted disordered rocksalt powder.

[0101] Illustration 28. The method of illustration 27, wherein the Li reinserted disordered rocksalt powder is separated and vacuum dried.

[0102] Illustration 29. The method of either illustration 27 or 28, wherein the solution comprised of lithium is a LiOH solution having a pH of at least 11.Examples

[0103] To synthesize Li1.2Mno.4TiO.4O2 (NM-LMTO) using the molten-salt synthesis (NM) method, a stoichiometric amount of Mn20a (Sigma- Aldrich, 99%), TiOi (Sigma- Aldrich, 99.7%), and a 5 wt% excess of Li2COi (Thermo-Scientific, 99%) were utilized as the LMTO precursors. A salt such as CsBr (Thermo-Scientific, 99%), CsCl (Sigma-Aldrich, 99.9%), CsI (Sigma-Aldrich, 99.9%), KBr (Thermo-Scientific, 99%), KC1 (Sigma- Aldrich, 99-100.5%), or KI (Sigma- Aldrich, 99%) was added as the molten salt flux, maintaining a precursor-to-salt weight ratio of 1:1.5. A total of 7.5 g of salts and 5 g of precursors were dispersed in 15 ml of acetone (Sigma- Aldrich, > 99.5%) and mixed using a Fritsch Planetary Micro Mill (PULVERISETTE 7) at 500 rpm for 6 hours in a 45 ml stainless steel jar, with twenty 10 mm stainless steel balls serving as the grinding medium. The resulting mixture was collected and dried overnight in a vacuum oven at 80°C.

[0104] Two grams of the dried precursor- salt mixture were placed in a crucible and heated using a rapid heating furnace (MTI OTF-1200X-4-RTP) at a ramping rate of l°C / s to a specified temperature and duration for the initial calcination step (e.g., 800°C for 5 minutes) under argon. The sample was then furnace-cooled to produce NM-LMTO with solidified CsBr.

[0105] In the next stage, the samples were annealed in an Ar atmosphere without removing the molten-salt flux, using another furnace (MTI OTF-1200X-S). During annealing, the temperature is increased at a rate of 5°C / min to the set anneal temperature (e.g., 500°C or 600°C, which are below the molten salt's melting point). The annealing process was conducted for different durations of 2, 5, 10, and 20 hours.

[0106] For CsBr removal, the samples were sonicated in 50 ml of deionized water (DIW) underArgon flow for 15 minutes, followed by washing with 1000 ml of DIW under Argon flow for 30 minutes. The resulting powder was then collected through vacuum filtration under Argon.

[0107] Next, the collected powder underwent a Li-reinsertion step. Approximately 1.5 g of the DIW-washed NM-LMTO particles were immersed and stirred in a highly concentrated LiOH (Sigma-Aldrich, > 98%) solution (12.5 g LiOH in 100 ml DIW) for 6 hours under Argon flow. Finally, the powder was collected via vacuum filtration under Argon and dried in a vacuum oven.

[0108] To synthesize LMTO through solid-state synthesis (S-LMTO), stoichiometric amounts of M112O3 (Sigma-Aldrich, 99%) and TiO2 (Sigma-Aldrich, 99.7%), along with a 10 wt% excess of Li2CO3(Thermo-Scientific, 99%), were used as precursors. These precursors were mixed using a Fritsch Planetary Micro Mill (PULVERISETTE 7). Five grams of the mixture were placed in a 45 ml stainless- steel jar with twenty 5 mm diameter and ten 10 mm diameter stainless-steel balls. The ball mill was operated at 400 rpm for 6 hours. Following mixing, the powders were collected in an Ar-filled glovebox. Two grams of the mixed powder were then calcined in a furnace (MTI OTF-1200X-S) at 1000°C in an Ar flow for 2 hours, with a ramping rate of 5°C / min, to produce SLMTO. To prepare pulverized LMTO (PS-LMTO), the S-LMTO powder was further milled using the Fritsch Planetary Micro Mill (PULVERISETTE 7) at 500 rpm for 5 hours. For this, 2 grams of S-LMTO were loaded into a 45 ml stainless-steel jar containing five 10 mm diameter and ten 5 mm diameter stainless-steel balls.

[0109] Figures 1 and 2 show the SEM image and XRD pattern of Li1.2Mno.4Tio.4O2 (S-LMTO) synthesized using a solid-state method (in the absence of salt) at 1000°C for 12 hours, showing large LMTO particles with the diameter (<7) of ~5 pm. This is the typical morphology of Mn-DR that arc made via the solid-state synthesis method. Figures 3 and 4 show the SEM image and XRD pattern of NM-LMTO when made through using CsBr as the salt with the salt to DRP ratio (by weight) of 1 : 1.5 at 830 °C for 7 mins; without a further annealing step. From the SEM image, we can see that the particle size of LMTO can now be as small as 100-500 nm. Also, the XRD pattern shows the typical Mn-DR pattern demonstrating the method can produce well-crystallized Mn-DR particles with good crystallinity.

[0110] Li1.2Mno.eNbo.2O2 (Mn-DR) is synthesized by the salt method. Figures 5 and 6 show the SEM image and XRD pattern of LMNO made with using KBr with a salt to precursor ratio (by weight) of 1:0.5 at 950°C for 10 minutes) and average heating rates of at least about 1 °C / min. We can see that even LMNO can be made into c / ~500 nm particles with the method displaying excellent crystallinity and phase purity.

[0111] Annealing at a temperature below the melting point of salt (c.g., 636 °C for CsBr) has been demonstrated for improving the phase crystallinity, removing compositional inhomogeneity within Mn-DR particles without increasing the particle size. The crystallinity (X-ray diffraction patterns) of Li1.2Mno.4Tio.4O2 (LMTO) first synthesized using CsBr with the salt to precursor ratio (1 : 1.5 by weight) at 83O°C for 7mins and after annealing at 600°C for 10 hours under Ar are shown Figures 7-9. The Figures of the XRD, SEM, and EDS results of LMTO before and after the annealing. The LMTO was first made by heating and cooling at a rate of aboutl °C / s ramping, 830 °C for 7 min, and precursor: salt = 1:1.5 by weight). The XRD patterns in Figure 4 show that after the further annealing, the XRD peaks look sharper and are shifted to higher angles, meaning that the crystallinity of LMTO is improved after reannealing along with the decrease of the lattice parameters of the LMTO crystal structure. The XRD refinement shows that the lattice parameter o 0 of LMTO changes from a = 4.1663 A to 4.154109 A after the reannealing, such that the lattice parameter also changes toward the values reported for the LMTO synthesized using a solid state method.

[0112] EDS results on the before and after argon annealing of the NM-LMTO (Figures 8 and 9) show that the as-made NM-LMTO has Ti-rich surface and Mn-rich core (indicating compositional inhomogeneity) structure, which is removed after the annealing. Combining the XRD, SEM, and EDS results, it is apparent the annealing enhances the crystallinity and uniformity of the LMTO. LMNO displays similar results when further annealed in the salt below the salt’s melting point (i.e., minimal or essentially no further particle growth).

[0113] NM-LMTO is immersed in a 11.9 pH LiOH aqueous solution for a time of 6 hours at room temperature ~23 °C while agitating and separated for further annealing as described above. Table 1 shows that DIW washed NM-LMTO had a deficiency of Li but after reinsertion of Li by immersing in a LiOH solution the stoichiometry approaches the target stoichiometry. ICP (inductively coupled plasma)-Mass Spectroscopy analysis is used to determine the stoichiometry.Table 1

[0114] Figures 10 and 11 are SEM micrographs of the DR (NM-LMTO) powder before annealing and after annealing show there is little particle growth, which is also shown by a laser diffractometry particles size analysis (Figure 12).

[0115] Figures 13 to 15 show the battery performance of one or more electrodes using NM- LMTO of the invention. Figure 13 shows the effect of the reaction time and temperature to form the NM-LMTO of electrodes composed of 70 wt% NM-LMTO or PS-LMTO, 20 wt% carbon black (CB), and 10 wt% polyvinylidene fluoride (PVDF). The carbon mixing of the NM-LMTO is performed by gentle mixing essentially without further pulverization. The PS-LMTO pulverization by high intensity is milling is used as commonly performed in the art as described above (i.e., planetary milling). The electrodes are made by casting from a NMP slurry of the aforementioned components on a metal current collector. The effect of annealing is shown in Figure 14. Figure 15 shows the effect of lithium reinsertion. Figure 16 shows the capacity retention of DR (NM-LMTO) made by the method of this invention and DR made by solid state synthesis (PS-LMTO) in the electrodes composed of 70 wt% NM-LMTO or PS-LMTO, 20 wt% multi-walled carbon nanotubes (MWCNT), and 10 wt% PVDF, cycled between 1.5-4.8 V at 20 mA / g and 25°C. PS-LMTO initially achieves a discharge capacity of around 323 mAh / g but quickly decays to about 123 mAh / g after 100 cycles (38.1% capacity retention), corresponding to a capacity loss of 2 mAh / g per cycle. In contrast, NM-LMTO exhibits an initial discharge capacity of approximately 223 mAh / g, decreasing to about 188 mAh / g after 100 cycles (84.3% capacity retention), resulting in an average capacity loss of 0.35 mAh / g per cycle. This demonstrates that NM-LMTO significantly outperforms PS-LMTO in terms of capacity retention. NM-LMTOsynthesized with 800°C for 5 minutes of calcination and 600°C for 10 hours of annealing (instead of 600°C for 20 hours of annealing) displays similar performance.

[0116] The NM-LMTO demonstrates significantly better voltage retention than PS-LMTO. Figures 17 and 18 show the dQ / dV plots of PS- and NM-LMTO from the 1.5-4.8 V cycling test. For PS-LMTO, the discharge dQ / dV peak at approximately 3.4 V in the first cycle is quickly lost upon cycling, and a new discharge dQ / dV peak at around 2.4 V appears after 100 cycles. Additionally, the initial charging dQ / dV peaks at approximately 3.4 V and 4.4 V are completely lost upon cycling, showing no clear oxidation peaks after 100 cycles. In contrast, 15 NM-LMTO’ s discharge dQ / dV peaks shift more slowly from around 3.4 V to 2.7 V over 100 cycles, and its charging dQ / dV peaks remain more clearly defined upon cycling. This indicates more reversible redox processes in NM-LMTO than in PS-LMTO. As a result, NM-LMTO’ s average discharge voltage loss is much slower than that of PS-LMTO, changing from approximately 3.05 V to 2.61 V for NM-LMTO (4.4 mV loss per cycle on average), compared to a change from around 3.1 V to 2.3 V for PS-LMTO (8 mV loss per cycle on average) as shown in Figure 19.

[0117] The 70(NM / PS-LMTO):20(MWCNT):10(PVDF) electrodes before and after cycling are examined to showing the effect of LMTO’s particle morphology on the electrode microstructure and degradation.

[0118] Figures 20 to 23 show cross-sectional SEM images of the PS- and NM-LMTO electrodes before cycling and after 40 cycles. In these SEM images, LMTO particles appear in white (bright gray), MWCNT-PVDF in dark gray, and pores in black. The most notable difference between the two electrodes is the distribution of LMTO particles within the electrode matrix. The PS-LMTO electrode exhibits a non-uniform distribution of active material, with some pulverized PS-LMTO nanoparticlcs agglomerating into large secondary particles (< > 1 pm), along with debris-like nanoparticles showing irregular shapes. In contrast, the NM-LMTO electrode exhibits a much more uniform distribution of sub-200 nm LMTO particles, where each particle is a single crystal. Such uniform DR distribution in the electrode film is unique and novel. Electrode uniformity improves capacity retention, which is attributed to the uniformity of the particles and lack of asperities arising from the necessity to comminute solid state synthesized DR. It is believed that the uniformity of the NM-LMTO particles results in more homogeneous reactions for each particle and creates uniform stress-strain arising from volume changes during cycling.

[0119] In contrast, PS-LMTO's particle pulverization after solid-state synthesis generates significantly agglomerated secondary particles a wide particle size distribution with particles having comminution asperities.

[0120] The SEM images of the electrodes after 40 cycles shows that the NM-LMTO electrode experiences more homogeneous and reduced degradation upon cycling compared to the PS-LMTO electrode. Both electrodes exhibit increased porosity after 40 cycles, indicated by the increased black spots in the SEM images. However, the overall porosity increase is smaller for the NM-LMTO electrode, and its distribution is more uniform across the electrode than that of the PS-LMTO electrode. The distribution of pores in the NM-LMTO electrode is believed, without being limiting to be due to the homogeneous distribution of electrode components, leading to a more even development of stress and strain in the electrode matrix and more uniform electrolyte soaking upon cycling.

[0121] It is noteworthy that NM-LMTO particles do not develop intragranular cracks after 40 cycles. This absence of NM-LMTO cracking is likely due to their lack of asperities, uniform morphology and small particle size.

[0122] Figures 24 and 25 show the X-ray diffractograms of the DR before cycling (BC) and of the cycled electrodes (40 and 100 cycles). Before cycling, the (002) peak positions are nearly identical, reflecting similar lattice parameters for PS-LMTO (4.144 A) and NM-LMTO (4.149 A). However, the NM-LMTO peak is much sharper, indicating higher crystallinity. After 40 and 100 cycles, the irreversible shift of the (002) peak to a lower angle is more significant for PS-LMTO than NM-LMTO. This behavior reflects greater irreversible volume expansion for PS-LMTO after cycling, as indicated by the change in lattice parameter from 4.144 A (Before cycle) to 4.248 A (40 cycles) and 4.227 A (100 cycles) for PS-LMTO, compared to the change from 4.149 A (Before cycle) to 4.198 A (40 cycles) and 4.202 A (100 cycles) for NM-LMTO. This lattice parameter increase after cycling is most likely due to more significant oxygen loss from PS-LMTO than NM- LMTO, as oxygen loss is expected to lead to more reduced transition metal species with larger ionic radii at the discharged state. We note that even for NM-LMTO, there is peak broadening after 40 and 100 cycles, although to a lesser degree than in PS-LMTO. Considering the absence of intragranular cracking in NM-LMTO, this peak broadening is most likely due to crystallinity loss of LMTO upon cycling, where irreversible rearrangements of ions take place.

[0123] the crystallinity and phase purity of the samples, X-ray diffraction patterns were collected using a Malvern PANalytical Empyrean X-ray diffractometer with a copper source spanning a 20 range from 10° to 90°. For X-ray diffraction (XRD) analysis of the electrodes before and after cycling, the coin cells were carefully opened in a controlled inert atmosphere inside an Ar-filled glove box. The electrodes were then briefly immersed in dimethyl carbonate (DMC) to remove any residual electrolyte species. To conduct X-ray diffraction (XRD) on the electrode film without exposure to air, an airtight holder with a zero-background plate was employed. For enhanced data analysis, Rietveld refinement was performed using the PANalytical X'pert HighScore Plus software.

[0124] The cross-sections of NM-LMTO particles, both before and after argon annealing were prepared using a Hitachi Ethos NX5000 focused ion beam scanning electron microscope (FIBSEM). The powder samples were placed onto double-sided carbon tape. Before FIB processing, platinum (Pt) was deposited onto the surfaces via electron beam-assisted deposition (EBD) to protect the samples and fill gaps between individual particles, thus preserving the integrity of the lamella.

[0125] EELS spectra of the cross-sectional samples were acquired using a Thermo-Scientific Talos F200X STEM operated at 200 keV, equipped with a Gatan Enfinium ER Model 977 EEL spectrometer with a collection angle of 25.11 mrad. The DUAL-EELS acquisition mode was employed to simultaneously capture both the low-loss and core-loss regions, with an energy dispersion of 0.25 eV / channel. Both core-loss and low-loss signals were aligned and calibrated using the zero-loss peak. The particle size of NM- and PS-LMTO was determined using a Hitachi SU-8000 scanning electron microscopy (SEM) and a Malvern Zetasizer Nano ZS instrument.

[0126] Elemental analysis of NM-LMTO was conducted before and after Li-rcinscrtion using inductively coupled plasma optical emission spectrometry (ICP-OES) with the Thermo Scientific iCAP 6000 series, which provides a detection limit below 1 ppm and an analytical error of less than 5%. The Mn concentration in the lithium chip of the cycled NM-LMTO and PS-LMTO electrodes was measured using the same ICP-OES instrument. Standard solutions of Li, Mn, and Ti were prepared by diluting Sigma-Aldrich stock solutions: Li (998 mg / L ± 4 mg / L), Mn (1003 mg / L ± 5 mg / L), and Ti (1000 mg / L ± 2 mg / L). For the NM-LMTO powder, sample preparation involved digestion with a mixture of H2O2 and HNOs in a 3:4 w% ratio. For the detection of Mnon the lithium chip, the coin cell was disassembled in the glovebox, and the lithium chip was then rinsed with a 2 wt% HNO3 solution.

[0127] The cross-sections of the electrode films of NM-LMTO and PS-LMTO, both before and after 40 cycles, were prepared using a Hitachi IM4000Plus Ar ion milling system at 6 keV. Subsequently, SEM images of the electrode films were captured using a Hitachi SU9000 SEM / STEM at 1.2 kV. Energy dispersive X-ray spectroscopy (EDS mapping) was conducted using the Oxford Instruments Extreme detector.

[0128] Li1.1Mno.7Tio.2O2, is synthesized by the NM method described above for Li12Mno.4TiO4O2. The synthesis temperature is 900°C for 1 min without a second annealing below the salt’s melting temperature. The salt used is CsBr. LiOH, M 11203. and TiO2 are the Lii.1Mno.7Tio.2O2 precursors in the precursor-to-salt weight ratio of 1:1.5. The X-ray diffraction pattern showing the disordered rocksalt phase is shown in Figure 26 and the particles are displayed in the SEM of Figure 27 demonstrating the applicability of the method to differing DRs and spherical morphology that may be realized.

Claims

WHAT IS CLAIMED IS:

1. A method to form a disordered rocksalt powder comprising, heating, at an average heating rate, disordered rocksalt precursors in a salt to a reaction temperature above the salt’s melting point for a reaction time to form the disordered rocksalt powder in the salt, cooling, the disordered rocksalt powder and salt to below the salt’s melting point at an average cooling rate, and separating the disordered rocksalt powder from the salt, the average heating and cooling rate being at least 5 °C / min when heating between the salt’s melting point to the reaction temperature.

2. The method of claim 1, wherein the disordered rocksalt powder and salt are present in a weight ratio of at least 0.

253. The method of claim 1, wherein the salt has a cation radius that is at least 1.2 times greater than lithium’s cationic radius.

4. The method of claim 1, wherein the salt’s melting point is at least 400 °C to 800 °C.

5. The method of claim 1, wherein the salt is comprised of one or more of KBr, KC1, KI, CsBr, CsCl.

6. The method of claim 1, wherein the average cooling rate is at least 1 °C / second between the salt’s melting point to the reaction temperature.

7. The method of claim 1, wherein the reaction time is at most 60 minutes at the reaction temperature.

8. The method of claim 1, wherein the disordered rocksalt powder is comprised of primary particles having an average particle size of at most 2 micrometers equivalent spherical diameter and at least 65% of the primary particles have a circularity of at least 0.65.

9. The method of any one of the preceding claims, wherein the salt and the disordered rocksalt precursors are each a powder having an average particle size of less than 20 micrometers.

10. The method of claim 1, wherein the disordered rocksalt precursor have differing solubilities in the salt at the reaction temperature and reaction time.

11. The method of claim 10, wherein disordered rocksalt precursors having a lower solubility are incompletely dissolved in the salt at the reaction temperature.

12. The method of claim 1 further comprising, prior to separating, annealing the salt and the disordered rock salt powder at an annealing temperature that is at least 300 °C to below the salt’s melting point.

13. The method of claim 12, wherein the annealing is at an annealing temperature of 500 °C to 800 °C for an annealing time of at most 24 hours.

14. The method of claim 1, wherein the cooling has an average cooling rate of at least 10 °C / minute when cooling from the reaction temperature to the salt’s melting point.

15. A powder comprised of unagglomerated disordered rocksalt primary particles having a maximum particle size of at most 2 micrometers and at least 60% of the primary particles by number have a circularity of at least 0.65.

16. The powder of claim 15, wherein at least 70% of the primary particles by number have a circularity of at least 0.8.

17. The powder of claim 15, wherein the primary particles have a D90 of at most about 1.5 micrometers, D50 that is submicrometer, and a D10 of at least 0.1 micrometer.

18. The powder of claim 15, wherein the disordered rocksalt powder has a trace amount of one or more of K, Cs, Br and Cl.

19. The powder of claim 15, wherein the disordered rocksalt powder has a chemistry represented byLixM yMzO2-(a+b)Fa Zb where 1.0<x<1.75; 0<y<0.55; 0.1<z<l; 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 .

20. The powder of claim 19, wherein M is comprised of one or more of Ti, Mn, Fe, Co,V, Cr, Ni and Cu.

21. The powder of claim 20, wherein M is comprised of Ti and Mn.

22. The powder of claim 19, wherein M’ is comprised of Nb.

23. A cathode comprised of the disordered rocksalt powder of claim 15 and carbon.

24. The method of claim 1, wherein the salt is removed by washing with water and separating to form a washed disordered rocksalt powder.

25. The method of claim 24, where the water has a pH of 6 to 8.

26. The method of claim 24, wherein the water has been deionized.

27. The method of 24, wherein the washed disordered rocksalt powder is immersed in a solution comprised of Li to form a Li reinserted disordered rocksalt powder.

28. The method of claim 27, wherein the Li reinserted disordered rocksalt powder is separated and vacuum dried.

29. The method of claim 27, wherein the solution comprised of lithium is a LiOH solution having a pH of at least 11.

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