Cathode material having lithium phosphate surface species

Abstract

This disclosure relates to lithium phosphate species for coated cathode active materials, which are used in the cathode (i.e., positive electrode) of rechargeable lithium batteries, and lithium ions (Li + It is useful for reversibly storing )

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority and benefits of U.S. Provisional Patent Application No. 63 / 509,126, filed on 20 June 2023, which is incorporated herein by reference in its entirety, regardless of its purpose. This disclosure relates to lithium ions (Li + This relates to lithium phosphate species for coated cathode active materials useful for the cathode (i.e., positive electrode) of rechargeable lithium batteries that reversibly store ) [Background technology]

[0002] Currently, there is an unmet need in the field of rechargeable lithium batteries for cathode active materials that are stable at high voltages (e.g., 4.2V for lithium metal) and / or high temperatures (e.g., 60°C). This instability tends to lead to an increase in the internal resistance of the battery during storage, charging, use, or both.

[0003] Some solid electrolyte materials tend to be unstable at high voltages or temperatures. These solid electrolyte materials can react with the cathode active material. The cathode active material can also oxidize when exposed to high voltages or temperatures. These are some of the causes of reduced battery performance. Some researchers have attempted to coat the cathode active material with LiNbO3, Li2ZrO3, and LiTaO3 to prevent oxidation. See, for example, U.S. Patent Application Publication 2016 / 0156021, U.S. Patent Application Publication 2019 / 0044146, and U.S. Patent No. 9,692,041. See also Chem. Mater. 2018, 30, 22, 8190-8200, (doi.org / 10.1021 / acs.chemmater.8b03321), Adv. Energy Mater. 2020, 10, 1903778 (doi.org / 10.1002 / aenm.201903778), and Journal of Power Sources Volume 248, 15 February 2014, Pages 943-950, (doi.org / 10.1016 / j.jpowsour.2013.10.005). However, these previously reported coatings had poor stability and / or other drawbacks. For example, 4.2V (Li / Li +At high potentials (relative to ), the internal resistance of these coatings increased rapidly when charged. For these and other reasons, these previously reported coatings were inferior in several respects. Heating the cathode is another way to prevent oxidation, and researchers have studied the effect of heating temperature on battery performance. Generally, better performance is achieved at higher temperatures in the range of 750°C to 800°C (Lee, SH, et al. Journal of Power Sources 184 (2008) 276-283 and Tang, Z. et al., Journal of Alloys and Compounds 693 (2017) 1157-1163). As reported in U.S. Patent No. 9,972,826, heating temperatures in the range of 400 to 650°C reduce the resistance within the battery compared to heating temperatures of 300°C to 350°C and 700°C. However, high heating temperatures require a large amount of energy, which increases the cost and consumption of fuel needed to generate that energy and can potentially be harmful to the cathode. It is advantageous to develop energy-efficient methods to mitigate unwanted reactions in the cathode. This specification describes methods for preventing unwanted reactions in the cathode. [Overview of the project]

[0004] This specification describes a method for producing cathode active material particles coated with lithium phosphate species, comprising the steps of: 1) coating cathode active material particles with a reaction mixture comprising a lithium precursor, a phosphorus precursor, and a solvent, wherein the molar ratio of Li:P in the reaction mixture is about 3:1 to 1:3; 2) removing the solvent from the reaction mixture; and 3) heating the cathode active material particles under dry air conditions or an O2 atmosphere at a temperature of about 250°C to 375°C to form cathode active material particles coated with lithium phosphate species. In one embodiment, the molar ratio of Li:P in the reaction mixture is about 3:1 to 3:3. In one embodiment, the phosphorus precursor is P2O5. In one embodiment, the temperature is about 350°C to 375°C. In one embodiment, the temperature is about 300°C to 350°C. In one embodiment, the temperature is about 250°C to 300°C. In one embodiment, the temperature is about 375°C. In one embodiment, the temperature is about 350°C. In one embodiment, the temperature is approximately 300°C. In another embodiment, the temperature is approximately 250°C.

[0005] This specification also describes compositions comprising cathode active material particles and a coating in contact with the cathode active material particles, wherein the coating comprises a lithium phosphate species, and the cathode active material particles are coated at a temperature of about 250°C to 375°C using a reaction mixture comprising a lithium precursor and a phosphorus precursor in a Li:P molar ratio of about 3:1 to 1:3. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:1 to 3:3. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:1. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:2. In one embodiment, the temperature is about 350°C to 375°C. In one embodiment, the temperature is about 300°C to 350°C. In one embodiment, the temperature is about 250°C to 300°C. In one embodiment, the temperature is about 375°C. In one embodiment, the temperature is about 350°C. In one embodiment, the temperature is about 300°C. In one embodiment, the temperature is about 250°C. [Brief explanation of the drawing]

[0006] [Figure 1] This is a non-limiting embodiment of a schematic diagram of a spray coating process, illustrating one non-limiting method for producing the coated active material described herein. [Figure 2] This graph compares the median ASR change over a three-month period for batteries fabricated with cathode 1 (Li:P ratio of the starting material at 250°C) and batteries fabricated with an uncoated cathode. [Figure 3A] This graph shows the effect of heating temperature for cathodes 7-10 (Li:P ratio of 3:1) on the median ASR change over 28 days (each data point represents the average value of at least 30 experiments). [Figure 3B] This graph shows the effect of heating temperature for cathodes 7-10 (Li:P ratio of 3:1) on the median ASR change over 28 days (each data point represents the average value of at least 60 experiments). [Figure 4A] This graph shows the effect of heating temperatures (250°C and 375°C) on the median ASR change over time (each data point represents the average value from at least five experiments). [Figure 4B] This graph shows the effect of heating temperatures (250°C and 375°C) on the median ASR change over time (each data point represents the average value from at least 50 experiments). [Figure 5A] This graph shows the effect of cathode heating temperature (250°C and 375°C) and starting material ratio (Li:P ratio of 3:1 and 3:2) on the median ASR change over 56 days (each data point represents the average value from at least 5 experiments). [Figure 5B] This graph shows the effect of cathode heating temperature (250°C and 375°C) and starting material ratio (Li:P ratio of 3:1 and 3:2) on the median ASR change over 178 days (each data point represents the average value from at least 40 experiments). [Figure 6A]This graph shows the effect of the cathode coating starting material concentration on the median ASR change (each data point represents the average value from at least 5 experiments). [Figure 6B] This graph shows the effect of the cathode coating starting material concentration on the median ASR change (each data point represents the average value from at least 20 experiments). [Figure 7A] This graph shows the effect of the ratio of starting materials (Li:P ratios of 3:1, 3:2, and 3:3) on the median ASR change over 56 days (each data point represents the average value from at least 5 experiments). [Figure 7B] This graph shows the effect of the ratio of starting materials (Li:P ratios of 3:1, 3:2, and 3:3) on the median ASR change over 178 days (each data point represents the average value from at least 40 experiments). [Figure 8] This graph compares the change in discharge capacity of batteries made with cathode 1 and batteries made with an uncoated cathode over a three-month period. [Figure 9] This graph compares the gas generation over two days in batteries made with cathodes 1, 7, and 12, as well as in batteries made with uncoated cathodes. [Figure 10] This is a transmission electron microscope (TEM) image of an NMC core coated with lithium phosphate at a temperature of 250°C. The lithium phosphate coating, as measured by TEM, has a thickness of approximately 2.5 nm and is amorphous. [Figure 11] This is a TEM image of an NMC core coated with lithium phosphate at a temperature of 250°C. The lithium phosphate coating, as measured by TEM, has a thickness of approximately 11.5 nm to 15.9 nm and is amorphous. [Figure 12] This is a TEM image of an NMC core coated with lithium phosphate at a temperature of 375°C. The lithium phosphate coating is crystalline according to TEM measurements. [Figure 13]This is a TEM image of an NMC core coated with lithium phosphate, and the coating appears discontinuous as measured by TEM. [Modes for carrying out the invention]

[0007] definition As used herein, when modifying a number, the term “about,” for example, about 15% w / w, refers to the modified number and, optionally, a number within an approximate range that includes ±10% of that number. For example, about 15% w / w includes 13.5% w / w, 14% w / w, 14.5% w / w, 15.5% w / w, 16% w / w, or 16.5% w / w, as well as 15% w / w. For example, “about 75°C” includes 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, or 83°C, as well as 75°C.

[0008] As used herein, “selected from a group consisting of” means a single member of the group, more than one member of the group, or a combination of members of the group. Members selected from a group consisting of A, B, and C include, for example, A only, B only, or C only, as well as A and B, A and C, B and C, and A, B, and C.

[0009] As used herein, the term “dry air” refers to air with reduced humidity. Dry air may be supplied to a cleanroom. Dry air is characterized by having a dew point below -70°C.

[0010] As used herein, the term "cathode active material" refers to a substance that can insert lithium ions or react reversibly with lithium ions. The cathode active material is not particularly limited herein, and known prior art cathode active materials used in all-solid-state batteries can be used. In particular, when a metal oxide is used as the cathode active material, sintering of the secondary battery can be carried out in an oxygen-containing atmosphere. Specific examples of such cathode active materials include the following: manganese oxide (MnO), iron oxide, copper oxide, nickel oxide, lithium manganese-based composite oxides (e.g., Li x Mn2O4 or Li x MnO2), lithium nickel-based composite oxides (e.g., Li x NiO2), lithium cobalt-based composite oxides (e.g., Li x CoO2), lithium cobalt nickel oxide (LiNi 1-y Co y O2), lithium manganese cobalt-based composite oxides (e.g., LiMn y Co 1-y O2), spinel-phase lithium manganese nickel-based composite oxides (e.g., Li x Mn 2-y Ni y O4), lithium phosphate having an olivine structure (e.g., Li x FePO4, Li x Fe 1-y Mn y PO4, Li x CoPO4), lithium phosphate having a NASICON-type structure (e.g., Li7V2(PO4)3), iron(III) sulfate (Fe2(SO4)3), and vanadium oxide (e.g., V2O5) are included. These can be used alone or in combination of two or more. Preferably, x and y in these chemical formulas are within the ranges of 1 < x < 5 and 0 < y < 1. Among the above, LiCoO2, Li x V2(PO4)3, LiNiPO4, and LiFePO4 are preferred.

[0011] Additional examples of cathode active materials are LiMPO4 (M = Fe, Ni, Co, Mn), Li xFe (1-y) Mn y PO4 (where 1≦x≦5 and 0≦y≦1), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), and LiNi x Co y Al z O2 (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1). In these equations, x, y, and z are selected such that the equation is charge-neutral. In one embodiment, the cathode active material includes, but is not limited to, an NMC class cathode active material (LiNiCoMnO2), an LFP class cathode active material (LiFePO4 / C), and an LNMO class cathode active material (LiNi 0.5 Mn 1.5 The cathode active material is selected from any of the following members of the cathode active materials listed in Minnmann et al. Advanced Energy Materials, 2022, 12, 2201425: (containing but not limited to O4), NCA class cathode active materials (containing but not limited to LiMn2O4 and LiMn2O2), LMO class cathode active materials (containing but not limited to LiMn2O4), LCO class cathode active materials (containing but not limited to LiCoO2), or any of the cathode active materials listed in Minnmann et al. Advanced Energy Materials, 2022, 12, 2201425.

[0012] As used herein, the phrase "characterized by having an X-ray powder diffraction (XRD) pattern having at least one peak" means that, when a material is analyzed using X-ray powder diffraction, according to the techniques of the examples, the sample is observed to have at least the described XRD peaks and possibly other peaks. Peaks are locations of high intensity in the XRD pattern, which suggest the d-spacing (lattice plane spacing) of the crystalline unit cells that cause the observed XRD pattern when X-rays strike the material being analyzed by XRD.

[0013] As used herein, the phrase "measured by XPS" means that when the substance is analyzed as a loose powder by XPS or X-ray photoelectron spectroscopy according to the techniques of the Examples, the substance is observed to have an element-to-element or functional group-to-functional group atomic percentage ratio on the sample surface.

[0014] As used herein, the term “solid cathode” refers to a cathode that does not contain a liquid-phase electrolyte. As used herein, the terms “cathode” and “anode” refer to the electrodes of a battery. The cathode and anode are also often called the positive electrode and negative electrode, respectively, in related fields. During a charging cycle in a lithium secondary battery, Li ions move from the cathode through the electrolyte to the anode. During a charging cycle, electrons move from the cathode through the external circuit to the anode. During a discharging cycle in a lithium secondary battery, Li ions move from the anode to the cathode through the electrolyte. During a discharging cycle, electrons move from the anode through the external circuit to the cathode. As used herein, the term “positive electrode” refers to a positive ion, e.g., Li + This refers to the electrode in a secondary battery where the current is directed in the direction of conduction, flow, or movement during battery discharge. As used herein, the term "negative electrode" refers to a positive ion, e.g., Li + This refers to electrodes in a secondary battery where the lithium flows or moves during battery discharge. It includes a Li metal electrode and an electrode comprising a conversion chemistry, an intercalation chemistry, or a combination of conversion / intercalation chemistry (i.e., a cathode active material, e.g., NiF).x , NCA, LiNi x Mn y Co z O2[NMC] or LiNi x Al y Co z In a battery composed of O2[NCA] (where x+y+z=1), the electrode having a substance of conversion chemistry, intercalation chemistry, or a combination of conversion / intercalation chemistry is called the positive electrode. In some cases, the cathode is used instead of the positive electrode, and the anode is used instead of the negative electrode. When a lithium secondary battery is charged, Li ions are released into the cathode (e.g., NiF x Li ions move from the NMC (Non-metallic compound, NCA) towards the anode (e.g., Li metal). When a lithium secondary battery discharges, Li ions move from the negative electrode towards the positive electrode.

[0015] As used herein, the term “solid separator” refers to Li, which is substantially insulated from electrons. + This refers to ion-conducting materials (for example, lithium ion conductivity is at least 10 times greater than electronic conductivity). 3 Twice as large, often 10 6 (Twice as large), this acts as a physical barrier or spacer between the cathode and anode in an electrochemical cell. As used herein, the term “high voltage stable” refers to a material (e.g., a coated cathode active material) that does not react at high voltage (4.2V or higher for Li metal) in such a way that holding it at high voltage for at least three days substantially or significantly reduces the material’s ionic conductivity or resistance. In this specification, a substantial or significant reduction in ionic conductivity or resistance is an order of magnitude or greater reduction in ionic conductivity or an increase in resistance. As used herein, the term “high voltage” means at least 4.2V (i.e., v.Li) for lithium metal. High voltage may also refer to higher voltages, e.g., 4.3V, 4.4V, 4.5V, 4.6V, 4.7V, 4.8V, 4.9V, 5.0V or higher.

[0016] As used herein, high voltage means a voltage of 4.2V or greater relative to the lithium metal reference electrode (at 0V), unless otherwise specified. As used herein, the term “high temperature stable” means a substance that does not react at high temperatures (60°C or higher) in such a way that its ionic conductivity or resistance is substantially or significantly reduced when held at high temperatures for at least three days (e.g., a coated cathode active material). As used herein, area resistivity (ASR) is measured by electrochemical cycling using Arbin or Biologic equipment, unless otherwise specified.

[0017] As used herein, ionic conductivity is measured by electrical impedance spectroscopy, a method known in the art. As used herein, the terms “lithium phosphate species,” “LPO,” or “LPO species” refer to species containing lithium, phosphorus, and oxygen. As used herein, “percentage of surface” refers to the percentage of the geometric surface area of ​​a particle. For example, “60% of surface” refers to 60% of the geometric surface of a cathode active material particle. For example, for a spherical cathode active material particle, the geometric surface area is 4πr². 2 (Here, r is the radius of the spherical particle) is calculated as follows: 60% of the surface is (0.6)(4πr) of the cathode active material particles. 2 ) is coated, and the cathode active material particles are (0.4)(4πr 2 ) means that it is not coated.

[0018] As used herein, "d 50 The term "diameter" refers to the median size in a size distribution, measured by microscopy or other particle size analysis techniques, such as scanning electron microscopy or dynamic light scattering, but not limited to these. 50 This includes characteristic dimensions where 50% of the particles are smaller than the stated size.

[0019] As used herein, "d 90 The term "diameter" refers to the size in a size distribution, measured by microscopy or other particle size analysis techniques, such as scanning electron microscopy or dynamic light scattering, for example, but not limited to these. 90 "These particles contain characteristic dimensions, with 90% being smaller than the stated size." As used herein, the term “O2 atmosphere” refers to a gas atmosphere containing at least 99 volume percent (v / v) of oxygen (O2) gas, at least 99.5% v / v of O2 gas, at least 99.9% v / v of O2 gas, at least 99.99% v / v of O2 gas, or essentially pure O2 gas. As used herein, the terms “dry air conditions” or “dry air” refer to air with reduced humidity. Dry air may be supplied to a cleanroom. Dry air is characterized by having a dew point (dp) below -20°C, below -30°C, below -40°C, below -50°C, below -60°C, or below -70°C.

[0020] Lithium phosphate cathode coating This specification describes compositions comprising coated cathode active materials for cathodes in solid lithium rechargeable batteries. In some embodiments, the cathodes disclosed herein include solid cathode liquid. In some embodiments, the cathodes disclosed herein include liquid cathode liquid. In some embodiments, the coated cathode active material disclosed herein is used in a cathode containing a solid cathode solution. In some embodiments, the coated cathode active material disclosed herein is used in a cathode containing a liquid cathode solution.

[0021] This specification describes compositions comprising cathode active material particles and a coating in contact with the cathode active material particles, wherein the coating comprises a lithium phosphate species, and the cathode active material particles are coated at a temperature of 150°C to 375°C using a reaction mixture comprising a lithium precursor and a phosphorus precursor in a Li:P molar ratio of about 3:1 to 1:3. In some embodiments, the Li:P molar ratio in the reaction mixture is about 3:1 to 3:3. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:1. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:1.5. In one embodiment, the Li:P molar ratio in the reaction mixture is about 3:2. In one embodiment, the Li:P molar ratio in the reaction mixture is about 1:3. In one embodiment, the Li:P molar ratio in the reaction mixture is about 2:3. In one embodiment, the temperature is about 150°C to 350°C. In one embodiment, the temperature is about 150°C to 300°C. In one embodiment, the temperature is approximately 150°C to 250°C. In one embodiment, the temperature is between approximately 250°C and 375°C. In one embodiment, the temperature is approximately 350°C to 375°C. In one embodiment, the temperature is between approximately 300°C and 350°C. In one embodiment, the temperature is between approximately 250°C and 300°C. In one embodiment, the temperature is approximately 375°C. In one embodiment, the temperature is approximately 350°C. In one embodiment, the temperature is approximately 300°C. In one embodiment, the temperature is approximately 250°C. In one embodiment, the temperature is approximately 150°C.

[0022] In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0023] In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is a product of heating at approximately 375°C.

[0024] In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0025] In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0026] In one embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In yet another embodiment, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0027] In one embodiment, the lithium phosphate species is the reaction product of 0.0074 mol of LiOEt and 0.0025 mol of phosphorus precursor. In another embodiment, the lithium phosphate species is the reaction product of 0.0147 mol of LiOEt and 0.0049 mol of phosphorus precursor. In yet another embodiment, the lithium phosphate species is the reaction product of 0.0294 mol of LiOEt and 0.0980 mol of phosphorus precursor. In some embodiments, the lithium phosphate species is of the formula Li x P y O z The compound comprises (where 1.0 ≤ x ≤ 4.0, 0 ≤ y ≤ 2.0, and 2.0 ≤ z ≤ 7.0), and the formula is charge-neutral. In some embodiments, the lithium phosphate species is given by formula Li x P y O z The compound (where 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, and 2.0 ≤ z ≤ 3.7) is included, and the formula is charge-neutral.

[0028] In some embodiments, the lithium phosphate species is Li3PO4, LiPO3, Li4P2O7, a mixture of Li4P2O7 and Li3PO4 (i.e., Li4P2O7 / Li3PO4), a mixture of Li4P2O7 and LiPO3 (i.e., Li4P2O7 / LiPO3), an organolithium phosphate, or a combination thereof. In some embodiments, the lithium phosphate species is Li3PO4. In some embodiments, the lithium phosphate species is LiPO3. In some embodiments, the lithium phosphate species is Li4P2O7 / Li3PO4. In some embodiments, the lithium phosphate species is Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is an organolithium phosphate. In some embodiments, the organolithium phosphate is lithium diethyl phosphate, lithium dimethyl phosphate, lithium diisopropyl phosphate, lithium ethyl methyl phosphate, lithium ethyl isopropyl phosphate, lithium methyl isopropyl phosphate, dilithium methyl phosphate, dilithium ethyl phosphate, dilithium isopropyl phosphate, or a combination thereof.

[0029] In some embodiments, the lithium phosphate species is crystalline, amorphous, or a combination thereof. In some embodiments, the lithium phosphate species is crystalline. In some embodiments, the lithium phosphate species is amorphous. In some embodiments, the lithium phosphate species is both crystalline and amorphous.

[0030] In some embodiments, the lithium phosphate species is crystalline Li3PO4. In some embodiments, the lithium phosphate species is amorphous Li3PO4. In some embodiments, the lithium phosphate species is crystalline Li3PO4 and amorphous Li3PO4. In some embodiments, the lithium phosphate species is crystalline LiPO3. In some embodiments, the lithium phosphate species is amorphous LiPO3. In some embodiments, the lithium phosphate species is crystalline LiPO3 and amorphous LiPO3. In some embodiments, the lithium phosphate species is crystalline Li4P2O7. In some embodiments, the lithium phosphate species is amorphous Li4P2O7. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 and amorphous Li4P2O7. In some embodiments, the lithium phosphate species is a mixture of crystalline Li4P2O7 and crystalline Li3PO4 (i.e., crystalline Li4P2O7 / Li3PO4). In some embodiments, the lithium phosphate species is a mixture of amorphous Li4P2O7 and amorphous Li3PO4 (i.e., amorphous Li4P2O7 / Li3PO4). In some embodiments, the lithium phosphate species is a mixture of crystalline Li4P2O7 / Li3PO4 and amorphous Li4P2O7 / Li3PO4. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is amorphous Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 / LiPO3 and amorphous Li4P2O7 / LiPO3.

[0031] In one embodiment including any of the above, the phosphorus precursor is selected from P2O5, H3PO4, (NH4)3PO4, (NH3)3PO4, diethyl phosphate, dimethyl phosphate, or a combination thereof. In one embodiment including any of the above, the lithium precursor is selected from lithium hydroxide (LiOH), lithium ethoxide (LiOEt), lithium methoxide (LiOMe), metallic lithium, and a combination thereof. In one embodiment including any of the above, the phosphorus precursor is a sol-gel precursor such as a phosphorus alkoxide precursor. In one embodiment, the phosphorus precursor is P2O5. In one embodiment, the lithium precursor is LiOH. In one embodiment, the lithium precursor is LiOEt. In one embodiment, the coating is a discontinuous layer. In one embodiment, the coating is a continuous layer. In one embodiment, the coating is amorphous. In one embodiment, the coating is crystalline. In one embodiment, the coating contains crystalline domains as measured by TEM analysis. In one embodiment, the coating contains amorphous domains as measured by TEM analysis. In one embodiment, the coating contains crystalline and amorphous domains as measured by TEM analysis.

[0032] Some of these coatings may prevent or delay the aforementioned unwanted reactions that have been identified as reasons for reduced battery performance. When used in batteries, the newly disclosed coated cathode active materials described herein result in a more stable battery. In one embodiment, the coating is lattice-matched with the cathode active material. In one embodiment, the coating has a crystalline surface. In one embodiment, the coating has an amorphous surface. In one embodiment, the coating is a continuous coating. In one embodiment, the coating is a discontinuous coating. In this specification, "coating" refers to a substance bonded to the cathode active material, rather than the cathode active material itself, even if the cathode active material is an oxide, unless otherwise specified herein. For example, NMC is an oxide. However, other coatings bonded to NMC oxide are described herein. These other coatings, unlike the NMC oxide which is the cathode active material particle, are described above and below.

[0033] In one embodiment including any of the above, the coating further comprises amorphous domains based on transmission electron microscopy (TEM) analysis. In one embodiment including any of the above, the coating further comprises crystalline domains based on transmission electron microscopy (TEM) analysis. In one embodiment including any of the above, the coating further comprises amorphous domains based on transmission electron microscopy (TEM) analysis in addition to crystalline domains based on transmission electron microscopy analysis. In one embodiment including any of the above, the crystalline domain is in contact with the cathode active material. In one embodiment including any of the above, the amorphous domain is in contact with the cathode active material. In one embodiment including any of the above, the amorphous domain is not in contact with the cathode active material. In one embodiment including any of the above, the crystalline domain is in contact with the cathode active material, and the amorphous domain is in contact with the crystalline domain.

[0034] In one embodiment including any of the above, the amorphous domain is in contact with the cathode active material, and the crystalline domain is in contact with the amorphous domain. In one embodiment including any of the above, the coating is continuous. In another embodiment, the coating is discontinuous.

[0035] In a specific embodiment including any of the above, the coating has a thickness T of 1 nm ≤ T ≤ 20 nm, as measured by TEM analysis. In a specific embodiment including any of the above, the coating has a thickness T of 1 nm ≤ T ≤ 10 nm, as measured by TEM analysis. In a specific embodiment including any of the above, the coating has a thickness T of 1 nm ≤ T ≤ 3 nm, as measured by TEM analysis. In certain embodiments including any of the above, the coating has a thickness T of less than 1 nm, as measured by TEM analysis. In certain embodiments including any of the above, the coating has a thickness T of 1 nm ≤ T ≤ 20 nm, determined by scanning electron microscopy (SEM) analysis.

[0036] In certain embodiments including any of the above, T is approximately 1 nm, approximately 5 nm, or approximately 10 nm. In one embodiment including any of the above, T is approximately 1 nm. In one embodiment including any of the above, T is approximately 2 nm. In one embodiment including any of the above, T is approximately 3 nm. In one embodiment including any of the above, T is approximately 4 nm. In one embodiment including any of the above, T is approximately 5 nm. In a particular embodiment including any of the above, T is approximately 6 nm. In one embodiment including any of the above, T is approximately 7 nm. In one embodiment including any of the above, T is approximately 8 nm. In one embodiment including any of the above, T is approximately 9 nm. In one embodiment including any of the above, T is approximately 10 nm. In another embodiment including any of the above, T is approximately 11 nm. In another embodiment including any of the above, T is approximately 12 nm.

[0037] In certain embodiments including any of the above, T is approximately 0.8 nm to 10 nm. In one embodiment including any of the above, T is approximately 0.8 nm to 5 nm. In one embodiment including any of the above, T is approximately 0.8 nm to 2.5 nm. In one embodiment including any of the above, T is approximately 0.8 nm to 1.5 nm. In one embodiment including any of the above, T is approximately 1 nm to 4 nm. In one embodiment including any of the above, T is approximately 1.5 nm to 3.5 nm. In other embodiments including any of the above, T is approximately 5 nm to 10 nm. In one embodiment including any of the above, T is approximately 7 nm to 10 nm. In certain embodiments including any of the above, the coating is not a uniform layer, and T can vary in thickness from approximately 0.8 nm to 12 nm. In one embodiment including any of the above, T varies in thickness from approximately 0.8 nm to 5 nm. In one embodiment including any of the above, T varies in thickness from approximately 1 nm to 3.5 nm. In one embodiment including any of the above, T varies in thickness from approximately 1.5 nm to 4 nm. In one embodiment including any of the above, T varies in thickness from approximately 5 nm to 12 nm. In one embodiment including any of the above, T varies in thickness from approximately 5 nm to 8 nm.

[0038] In certain embodiments including any of the above, T is less than approximately 12 nm. In certain embodiments including any of the above, T is less than approximately 11 nm. In certain embodiments including any of the above, T is less than approximately 10 nm. In certain embodiments including any of the above, T is less than approximately 9 nm. In certain embodiments including any of the above, T is less than approximately 8 nm. In certain embodiments including any of the above, T is less than approximately 7 nm. In certain embodiments including any of the above, T is less than approximately 6 nm. In certain embodiments including any of the above, T is less than approximately 5 nm. In certain embodiments including any of the above, T is less than approximately 4 nm. In certain embodiments including any of the above, T is less than approximately 3 nm. In certain embodiments including any of the above, T is less than approximately 2 nm. In certain embodiments including any of the above, T is less than approximately 1 nm.

[0039] In certain embodiments including any of the above, T does not exceed the thickness that the TEM can detect, as described herein, for example. In certain embodiments including any of the above, the coating includes both crystalline and amorphous domains, with the thickness of the crystalline domains being approximately 0.8 nm to 5 nm and the thickness of the amorphous domains being approximately 0.8 nm to 5 nm. In one embodiment, the thickness of the crystalline domains is approximately 1 nm to 3 nm and the thickness of the amorphous domains is approximately 1 nm to 4 nm. In another embodiment, the thickness of the crystalline domains is approximately 1.5 nm to 2.5 nm and the thickness of the amorphous domains is approximately 2 nm to 4 nm. In one embodiment, the thickness of the crystalline domains is less than the thickness of the amorphous domains. In another embodiment, the thickness of the crystalline domains is greater than the thickness of the amorphous domains. In certain embodiments including any of the above, the crystalline domains are in contact with the cathode active material and the amorphous domains are in contact with the crystalline domains.

[0040] In any of the embodiments described above, the thickness is ±20% of the stated thickness. In any of the embodiments described above, the thickness is ±10% of the stated thickness. In one embodiment including any of the above, the coating crystalline domains are not lattice-matched with the crystalline domains of the cathode active material, as measured by TEM analysis. In one embodiment including any of the above, the coating crystalline domains are not lattice-matched with the crystalline domains of the cathode active material, as measured by SEM analysis. In one embodiment including any of the above, the coating crystalline domains are lattice-matched with the crystalline domains of the cathode active material, as measured by TEM analysis. In one embodiment including any of the above, the coating crystalline domains are lattice-matched with the crystalline domains of the cathode active material, as measured by SEM analysis. In one embodiment including any of the above, the coating further comprises a carbonate. In one embodiment including any of the above, the coating further comprises lithium carbonate.

[0041] In some embodiments, the composition comprises a zirconium-doped cathode active material. In some embodiments, the cathode active material is Zr-doped LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1). In some embodiments, the cathode active material is Zr-doped LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1). In some embodiments, the composition containing the coated cathode active material has a CO3:Zr ratio less than 15 as measured by X-ray photoelectron spectroscopy (XPS). In some embodiments, the composition containing the coated cathode active material has a CO3:Zr ratio less than 10 as measured by XPS. In some embodiments, the composition containing the coated cathode active material has a CO3:Zr ratio less than 5 as measured by XPS. In some embodiments, the composition containing the coated cathode active material has a CO3:Zr ratio below the detection limit of XPS. In some embodiments, the composition containing the coated cathode active material has a P:Zr ratio greater than 40 as measured by XPS. In some embodiments, the composition containing the coated cathode active material has a P:Zr ratio greater than 50 as measured by XPS.

[0042] In one embodiment including any of the above, the composition further comprises a second coating in contact with the first coating, the first coating in contact with cathode active material particles. In one embodiment including any of the above, the second coating is not Li3PO4.

[0043] In one embodiment including any of the above, the second coating has a chemical formula that is not the same as the chemical formula of the coating.

[0044] In certain embodiments including any of the foregoing, the second coating has the chemical formula: Li x B y O z (where 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6), Li x C y O z (where 0.4 ≤ x ≤ 1.8, 0.1 ≤ y ≤ 1, and 1 ≤ z ≤ 1.8), Li x Zr y O z (where 0 ≤ x ≤ 1.6, 0.2 ≤ y ≤ 1.0, and 2 ≤ z ≤ 1.2), Li x P y O z (where 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, and 2.0 ≤ z ≤ 3.7), Li x Zr y (PO4) z (where 0.05 ≤ x ≤ 1.5, 1 ≤ y ≤ 3, and 2.0 ≤ z ≤ 4.0), Li x Nb y O z (where 0.5 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.5, and 2 ≤ z ≤ 4), Li x Ti y O z (where 0 ≤ x ≤ 1.6, 0.2 ≤ y ≤ 1.0, and 2 ≤ z ≤ 1.2), Li x Ti y P w O z (where 0 ≤ x ≤ 2, 1 ≤ y ≤ 3, 1 ≤ w ≤ 4, and 2 ≤ z ≤ 20), Li x Zr y P w O z (where 0 ≤ x ≤ 2, 1 ≤ y ≤ 3, 1 ≤ w ≤ 4, and 2 ≤ z ≤ 20), Li x Zr y F z (where 0.2 ≤ x ≤ 0.75, 0.25 ≤ y ≤ 0.8, and 1.75 ≤ z ≤ 3.4), Li x Ti y F z (where 0.2 ≤ x ≤ 0.75, 0.25 ≤ y ≤ 0.8, and 1.75 ≤ z ≤ 3.4), Li x Al y F z(where 0.4≦x≦0.8, 0.2≦y≦0.6, and 1.4≦z≦2.2), Li x Y y F z (where 0.4≦x≦0.8, 0.2≦y≦0.6, and 1.4≦z≦2.2), Li x Nb y F z (where 0.2 ≤ x ≤ 0.8, 0.2 ≤ y ≤ 0.8, and 1.8 ≤ z ≤ 4.2), or compounds of a combination thereof. The subscripts x, y, and z are selected so that the compound is charge-neutral. In certain embodiments including any of the above, the second coating is of the formula: Li2CO3, Li3BO3, Li3B 11 O 18 , Li2ZrO3, Li3PO4, Li2SO4, LiNbO3, Li4Ti5O 12 , LiTi2(PO4)3, LiZr2(PO4)3, LiOH, LiF, Li4ZrF8, Li3Zr4F 19 This includes compounds such as Li3TiF6, LiAlF4, LiYF4, LiNbF6, ZrO2, Al2O3, TiO2, ZrF4, AlF3, TiF4, YF3, NbF5, or combinations thereof.

[0045] In one embodiment, the second coating contains Li2CO3. In one embodiment, the second coating contains Li3BO3. In one embodiment, the second coating contains Li3B 11 O 18 Includes. In one embodiment, the second coating includes Li2ZrO3. In one embodiment, the second coating includes Li3PO4. In one embodiment, the second coating includes Li2SO4. In one embodiment, the second coating includes LiNbO3. In one embodiment, the second coating includes Li4Ti5O 12Includes. In one embodiment, the second coating includes LiTi2(PO4)3. In one embodiment, the second coating includes LiZr2(PO4)3. In one embodiment, the second coating includes LiOH. In one embodiment, the second coating includes LiF. In one embodiment, the second coating includes Li4ZrF8. In one embodiment, the second coating includes Li3Zr4F 19 Includes. In one embodiment, the second coating includes Li3TiF6. In one embodiment, the second coating includes LiAlF4. In one embodiment, the second coating includes LiYF4. In one embodiment, the second coating includes LiNbF6. In one embodiment, the second coating includes ZrO2. In one embodiment, the second coating includes Al2O3. In one embodiment, the second coating includes TiO2. In one embodiment, the second coating includes ZrF4. In one embodiment, the second coating includes AlF3. In one embodiment, the second coating includes TiF4. In a particular example, the second coating includes YF3. In one embodiment, the second coating includes NbF5.

[0046] In one embodiment including any of the above, the second coating is amorphous as measured by TEM analysis. In one embodiment including any of the above, the second coating is crystalline as measured by TEM analysis. In one embodiment including any of the above, the second coating has a chemical formula that is not the same as the chemical formula of the coating. In one embodiment including any of the above, the second coating contains Li3BO3. In one embodiment including any of the above, the second coating contains Li x B y O z (where 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6). In one embodiment including any of the above, the second coating is Li2CO3, Li3BO3, Li3B 11 O 18 Li x B y O z , or combinations thereof. Formula Lix B y O z Then, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6. In one embodiment including any of the above, the second coating is Li x Zr y O z (where 0≦x≦1.6, 0.2≦y≦1.0, and 2≦z≦1.2). In one embodiment including any of the above, the second coating is Li x P y O z (where 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, and 2.0 ≤ z ≤ 3.7). In one embodiment including any of the above, the second coating includes Li3InCl6. In one embodiment, the first coating is of the formula Li x P a O d The compound comprises (where 0.05 ≤ x ≤ 1.5, 1.0 ≤ a ≤ 6.0, and 2.0 ≤ d ≤ 20.0), and the formula is charge-neutral. In one embodiment, the first coating is of formula Li x P a O d The compound comprises (where 0.5 ≤ x ≤ 7.0, 1.0 ≤ a ≤ 4.0, and 5.0 ≤ d ≤ 14.0), and the formula is charge-neutral. In one embodiment, the first coating is of formula Li x P a O d (where 0.5≦x≦2.0, 1.0≦a≦4.0, and 10.0≦d≦13.0) the compounds are charge-neutral. In one embodiment, the first coating is of formula Li x P a O d The compound comprises (where 1.0 ≤ x ≤ 4.0, 1.0 ≤ a ≤ 3.0, and 4.0 ≤ d ≤ 7.0) and the formula is charge-neutral. In one embodiment, the first coating is of formula Li x P a O d The compound comprises (where 1.0 ≤ x ≤ 3.0, 0 ≤ a ≤ 2.0, and 5.0 ≤ d ≤ 8.0), and the formula is charge-neutral. In one embodiment, the first coating is of formula Li x P a O dThe compound comprises (where 5.0 ≤ x ≤ 8.0, 0 ≤ a ≤ 2.0, and 6.0 ≤ d ≤ 9.0), and the formula is charge-neutral. In one embodiment, the first coating is of formula Li x P a O d The formula includes compounds (where 2.0 ≤ x ≤ 4, 0 ≤ a ≤ 2.0, and 2.0 ≤ d ≤ 5.0) and the formula is charge-neutral. In certain embodiments including any of the above, the first coating includes Li3PO4. In certain embodiments, the first coating includes Li3PO4 and the second coating includes Li3ZrPO6, Li5PZrO7, Li7ZrPO8, Li3PO4, Li2ZrO3, or Li 24 Zr3P 14 O 53 The chemical formula is selected from the following. In one embodiment, the first coating comprises Li3PO4, and the second coating comprises Li x Zr y P a O d The chemical formula includes (where 0.05≦x≦8.0, 0≦y≦3.0, 0≦a≦6.0, and 2.0≦d≦20.0), the formula is charge-neutral, and the second coating is not Li3PO4. In one embodiment, the first coating includes crystalline domains measured by TEM, and the second coating includes crystalline or amorphous domains measured by TEM. In one embodiment, the first coating includes amorphous domains measured by TEM, and the second coating includes crystalline or amorphous domains measured by TEM. In one embodiment, the first coating includes crystalline and amorphous domains measured by TEM, and the second coating includes crystalline or amorphous domains measured by TEM. This specification also describes coated cathode active material particles, which include cathode active material particles, the cathode active material particles comprising a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising Li3BO3, Li3B 11 O 18 Li x B y O z(Here, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6), or combinations thereof, the first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0047] This specification also describes coated cathode active material particles containing cathode active material particles, the cathode active material particles including a first coating and a second coating, the first coating including Li3PO4, and the second coating including Li x B y O z (Here, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6), or combinations thereof, the first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0048] This specification also describes coated cathode active material particles containing cathode active material particles, the cathode active material particles including a first coating and a second coating, the first coating including Li3PO4, and the second coating including Li3BO3, Li3B 11 O 18 , or combinations thereof, the first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating. This specification also describes coated cathode active material particles containing cathode active material particles, the cathode active material particles including a first coating and a second coating, the first coating including Li3PO4, and the second coating including Li x B y O z (Here, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6), Li x Zr y O z (Here, 0 ≤ x ≤ 1.6, 0.2 ≤ y ≤ 1.0, and 2 ≤ z ≤ 1.2), Li x P y O z(Here, 0.6 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.4, and 2.0 ≦ z ≦ 3.7), or combinations thereof, are included. The first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0049] This specification also describes coated cathode active material particles including cathode active material particles. The cathode active material particles include a first coating and a second coating. The first coating includes Li3PO4, and the second coating includes Li3BO3, Li3B 11 O 18 , Li2ZrO3, LiZr2(PO4)3, Li2SO4, Li x B y O z (Here, 0.2 ≦ x ≦ 0.75, 0.5 ≦ y ≦ 1.6, and 1.5 ≦ z ≦ 2.6), or combinations thereof, are included. The first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating. This specification also describes coated cathode active material particles including cathode active material particles. The cathode active material particles include a first coating and a second coating. The first coating includes Li3PO4, and the second coating includes Li x B y O z (Here, 0.2 ≦ x ≦ 0.75, 0.5 ≦ y ≦ 1.6, and 1.5 ≦ z ≦ 2.6), Li x Zr y O z (Here, 0 ≦ x ≦ 1.6, 0.2 ≦ y ≦ 1.0, and 2 ≦ z ≦ 1.2), Li x P y O z (Here, 0.6 ≦ x ≦ 1.5, 0.5 ≦ y ≦ 1.4, and 2.0 ≦ z ≦ 3.7) are included. The second coating is not Li3PO4. The first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0050] This specification also describes coated cathode active material particles, which include cathode active material particles, the cathode active material particles comprising a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising Li3BO3, Li3B 11 O 18 The coating comprises LZO, LiZr2(PO4)3, Li2SO4, or a combination thereof, wherein the first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0051] This specification also describes coated cathode active material particles, which include cathode active material particles, the cathode active material particles comprising a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising Li2CO3, Li3BO3, Li3B 11 O 18 The coating comprises LiZr2(PO4)3, Li2SO4, or a combination thereof, wherein the first coating is in contact with the cathode active material particles, and the second coating is in contact with the first coating.

[0052] This specification also describes coated cathode active material particles, wherein the cathode active material particles comprise a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising Li3BO3, the first coating in contact with the cathode active material particles and the second coating in contact with the first coating.

[0053] This specification also describes coated cathode active material particles, which include cathode active material particles, wherein the cathode active material particles comprise a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising LiZr2(PO4)3, the first coating in contact with the cathode active material particles and the second coating in contact with the first coating.

[0054] This specification also describes coated cathode active material particles, wherein the cathode active material particles comprise a first coating and a second coating, the first coating comprising Li3PO4 and the second coating comprising Li2SO4, the first coating in contact with the cathode active material particles and the second coating in contact with the first coating.

[0055] In certain embodiments including any of the above, the thickness of each coating is approximately 1 nm to 50 nm. This means that in these examples where the cathode active material particles have two coatings, each of the two coatings may have a thickness of 1 nm to 50 nm. Each coating may have the same or different thickness as the other coating. In one embodiment, one of the two coatings has a thickness of approximately 1 nm. In one embodiment, one of the two coatings has a thickness of approximately 2 nm. In one embodiment, one of the two coatings has a thickness of approximately 3 nm. In one embodiment, one of the two coatings has a thickness of approximately 4 nm. In one embodiment, one of the two coatings has a thickness of approximately 5 nm. In one embodiment, one of the two coatings has a thickness of approximately 6 nm. In one embodiment, one of the two coatings has a thickness of approximately 7 nm. In one embodiment, one of the two coatings has a thickness of approximately 8 nm. In one embodiment, one of the two coatings has a thickness of approximately 9 nm. In one embodiment, one of the two coatings has a thickness of approximately 10 nm. In one embodiment, one of the two coatings has a thickness of approximately 11 nm. In one embodiment, one of the two coatings has a thickness of approximately 12 nm. In one embodiment, one of the two coatings has a thickness of approximately 13 nm. In one embodiment, one of the two coatings has a thickness of approximately 14 nm. In one embodiment, one of the two coatings has a thickness of approximately 15 nm. In one embodiment, one of the two coatings has a thickness of approximately 16 nm. In one embodiment, one of the two coatings has a thickness of approximately 17 nm. In one embodiment, one of the two coatings has a thickness of approximately 18 nm. In one embodiment, one of the two coatings has a thickness of approximately 19 nm. In one embodiment, one of the two coatings has a thickness of approximately 20 nm. In one embodiment, one of the two coatings has a thickness of approximately 21 nm. In one embodiment, one of the two coatings has a thickness of approximately 22 nm.In one embodiment, one of the two coatings has a thickness of approximately 2.3 nm. In one embodiment, one of the two coatings has a thickness of approximately 24 nm. In one embodiment, one of the two coatings has a thickness of approximately 25 nm. In one embodiment, one of the two coatings has a thickness of approximately 26 nm. In one embodiment, one of the two coatings has a thickness of approximately 27 nm. In one embodiment, one of the two coatings has a thickness of approximately 28 nm. In one embodiment, one of the two coatings has a thickness of approximately 29 nm. In one embodiment, one of the two coatings has a thickness of approximately 30 nm. In one embodiment, one of the two coatings has a thickness of approximately 31 nm. In one embodiment, one of the two coatings has a thickness of approximately 32 nm. In one embodiment, one of the two coatings has a thickness of approximately 33 nm. In one embodiment, one of the two coatings has a thickness of approximately 34 nm. In one embodiment, one of the two coatings has a thickness of approximately 35 nm. In one embodiment, one of the two coatings has a thickness of approximately 36 nm. In one embodiment, one of the two coatings has a thickness of approximately 37 nm. In one embodiment, one of the two coatings has a thickness of approximately 38 nm. In one embodiment, one of the two coatings has a thickness of approximately 39 nm. In one embodiment, one of the two coatings has a thickness of approximately 40 nm. In one embodiment, one of the two coatings has a thickness of approximately 41 nm. In one embodiment, one of the two coatings has a thickness of approximately 42 nm. In one embodiment, one of the two coatings has a thickness of approximately 43 nm. In one embodiment, one of the two coatings has a thickness of approximately 44 nm. In one embodiment, one of the two coatings has a thickness of approximately 45 nm. In one embodiment, one of the two coatings has a thickness of approximately 46 nm. In one embodiment, one of the two coatings has a thickness of approximately 47 nm. In one embodiment, one of the two coatings has a thickness of approximately 48 nm. In one embodiment, one of the two coatings has a thickness of approximately 49 nm.In one embodiment, one of the two coatings has a thickness of approximately 50 nm. In one embodiment, the second of the two coatings has a thickness of approximately 1 nm. In one embodiment, the second of the two coatings has a thickness of approximately 2 nm. In one embodiment, the second of the two coatings has a thickness of approximately 3 nm. In one embodiment, the second of the two coatings has a thickness of approximately 4 nm. In one embodiment, the second of the two coatings has a thickness of approximately 5 nm. In one embodiment, the second of the two coatings has a thickness of approximately 6 nm. In one embodiment, the second of the two coatings has a thickness of approximately 7 nm. In one embodiment, the second of the two coatings has a thickness of approximately 8 nm. In one embodiment, the second of the two coatings has a thickness of approximately 9 nm. In one embodiment, the second of the two coatings has a thickness of approximately 10 nm. In one embodiment, the second of the two coatings has a thickness of approximately 11 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 12 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 13 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 14 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 15 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 16 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 17 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 18 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 19 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 20 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 21 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 22 nm.In one embodiment, the second coating of the two coatings has a thickness of approximately 23 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 24 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 25 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 26 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 27 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 28 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 29 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 30 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 31 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 32 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 33 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 34 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 35 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 36 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 37 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 38 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 39 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 40 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 41 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 42 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 43 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 44 nm.In one embodiment, the second coating of the two coatings has a thickness of approximately 45 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 46 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 47 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 48 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 49 nm. In one embodiment, the second coating of the two coatings has a thickness of approximately 50 nm.

[0056] In certain embodiments including any of the above, the thickness of each coating is approximately 1 nm to 20 nm. In certain embodiments including any of the above, the thickness of each coating is approximately 1 nm to 10 nm. In certain embodiments including any of the above, the thickness of each coating is approximately 1 nm to 3 nm.

[0057] Cathode active material In certain embodiments including any of the above, the cathode active material of the particles is LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), and LiNi x Co y Al z O2 is selected from (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1).

[0058] In certain embodiments including any of the above, the cathode active material of the particles is MnO, Li x Mn2O4, Li x MnO2, Li xKiO2, Li x CoO2, LiNi (1-y) Co y O2, LiMn y Co (1-y) O2, Li x Mn (2-y) Ni y O4, Li x FePO4, Li x Fe (1-y) Mn y PO4, Li x The material is selected from CoPO4, Li7V2(PO4)3, Fe2(SO4)3, V2O5, or a combination thereof, and the conditions are 1≦x≦5 and 0≦y≦1.

[0059] In certain embodiments including any of the above, the cathode active material is selected from lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), and combinations thereof.

[0060] In certain embodiments including any of the above, the cathode active material is a member of the NMC class of cathode active materials, for example, LiNiCoMnO2. In certain embodiments including any of the above, the cathode active material is a member of the LFP class of cathode active materials, for example, LiFePO4 / C. In certain embodiments including any of the above, the cathode active material is a member of the LNMO class of cathode active materials, for example, LiNi 0.5 Mn 1.5 O4 or LiNi 0.5 Mn 1.5 It is O2. In certain embodiments including any of the above, the cathode active material is a member of the NCA class of cathode active materials, e.g., LiMn2O4. In certain embodiments including any of the above, the cathode active material is a member of the LMO class of cathode active materials, e.g., LiMn2O4. In certain embodiments including any of the above, the cathode active material is a member of the LCO class of cathode active materials, e.g., LiCoO2. In one embodiment, the cathode active material is LiNiO2. In one embodiment, the cathode active material is LiNi1-x Co x It is O2(0.2 < x < 0.5). The cathode active material can be any useful known cathode similar to the cathode active materials described herein, even when the molar ratio of the composition changes. For example, the cathode active material can be any cathode active material described in Minnmann et al. Advanced Energy Materials, 2022, 12, 2201425.

[0061] In certain embodiments including any of the above, the cathode active material is LiMPO4 (M = Fe, Ni, Co, Mn), Li x Ti y O z (where x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn2O4, LiMn 2a Ni a O4 (where a is 0 to 2), LiCoO2, Li(NiCoMn)O2, Li(NiCoAl)O2, or nickel cobalt aluminum oxide. In certain embodiments including any of the above, the cathode active material is MnO, Li x Mn2O4, Li x MnO2, Li x NiO2, Li x CoO2, LiNi (1-y) Co y O2, LiMn y Co (1-y) O2, Li x Mn (2-y) Ni y O4, Li x FePO4, Li x Fe (1-y) Mn y PO4, Li x CoPO4, Li7V2(PO4)3, Fe2(SO4)3, V2O5, or a combination thereof, where 1 ≤ x ≤ 5 and 0 ≤ y ≤ 1.

[0062] In certain embodiments including any of the above, the cathode active material is LiMPO4 (M = Fe, Ni, Co, Mn), Li x Tiy O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), or LiNi x Co y Al z O2 is selected from (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1).

[0063] In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1). In one embodiment, the cathode active material is LiNi x Mn y Co z O2 (where x is 0.8, y is 0.1, and z is 0.1). In some other specific examples, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 0.6, y is 0.2, and z is 0.2). In one embodiment, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 0.5, y is 0.3, and z is 0.2). In some other examples, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 1 / 3, y is 1 / 3, and z is 1 / 3). In certain embodiments, the coated cathode active material is selected from LiMn2O4, LiCoO2, Li(NiCoMn)O2, or Li(NiCoAl)O2. In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1). In certain cases, the amount of lithium in the cathode active material changes depending on the charge state of the battery. For example, the amount of lithium is Li 0.95-1.1 (Ni x Mn y Co z ) can be in the range of O2 (where x, y, and z are as defined above). In some other specific example, the amount of lithium is Li 0.2-1.1 (Ni x Mn y Co z ) may be in the range of O2 (where x, y, and z are as defined above). Other ranges of lithium are also considered in this specification.

[0064] In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.97, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.95, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.9, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.85, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material is LiNi x Mny Co z O2 (where x+y+z=1, 0.80≦x≦0.83, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment, the cathode active material has a high nickel content, for example, LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.97, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2).

[0065] In some embodiments, the cathode active material includes particles with a diameter of approximately 1 μm to 20 μm as measured by transmission electron microscopy (TEM). In some embodiments, the cathode active material includes particles with a diameter of approximately 1 μm to 15 μm as measured by TEM. In some embodiments, the cathode active material includes particles with a diameter of approximately 1 μm to 10 μm as measured by TEM. In some embodiments, the cathode active material includes particles with a diameter of approximately 1 μm to 9 μm as measured by TEM. In some embodiments, the cathode active material includes particles with a diameter of approximately 1 μm to 8 μm as measured by TEM. In some embodiments, the cathode active material includes particles with a diameter of approximately 2 μm to 7 μm as measured by TEM. In some embodiments, the cathode active material includes particles with a diameter of approximately 2 μm to 5 μm as measured by TEM.

[0066] In some embodiments, the cathode active material is LiNi x Mn y Co z The material is O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) and contains particles with a diameter of approximately 1 μm to 20 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co zThe material is O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) and contains particles with a diameter of approximately 1 μm to 15 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) contains particles with a diameter of approximately 1 μm to 10 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) contains particles with a diameter of approximately 1 μm to 9 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z The material is O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) and contains particles with a diameter of approximately 1 μm to 8 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z The material is O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1) and contains particles with a diameter of approximately 2μm to 7μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z The solution is O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), and contains particles with a diameter of approximately 2μm to 5μm as measured by TEM.

[0067] In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 1 μm to 20 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Coz O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 1 μm to 15 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 1 μm to 10 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 1 μm to 9 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 1 μm to 8 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) contains particles with a diameter of approximately 2μm to 7μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z The sample is O2 (where x+y+z=1, 0.80≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1) and contains particles with a diameter of approximately 2μm to 5μm as measured by TEM.

[0068] In some embodiments, the cathode active material is LiNi x Mn y Co zO2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 1 μm to 20 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 1 μm to 15 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 1 μm to 10 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 1 μm to 9 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 1 μm to 8 μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1) contains particles with a diameter of approximately 2μm to 7μm as measured by TEM. In some embodiments, the cathode active material is LiNi x Mn y Co zO2 (where x + y + z = 1, 0.80 ≦ x ≦ 0.90, 0 ≦ y ≦ 0.2, and 0 ≦ z ≦ 0.2, x + y + z = 1), containing particles with a diameter of about 2 μm to 5 μm measured by TEM.

[0069] As described herein, the composition comprises: 1) a cathode active material selected from lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), or combinations thereof; and 2) a coating in contact with the cathode active material, the coating comprising a lithium phosphate species, and at least about 60% of the surface of the cathode active material is in contact with the coating.

[0070] As described herein, the composition comprises: 1) a cathode active material selected from lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), and combinations thereof; and 2) a coating in contact with the cathode active material, the coating comprising a lithium phosphate species, the lithium phosphate species being a reaction product of LiOEt and a phosphorus precursor, the molar ratio of Li:P in the reaction mixture being about 3:1 to 1:3, and the lithium phosphate species being a product by heating at about 250 °C to 375 °C. In some embodiments, the molar ratio of Li:P in the reaction mixture is about 3:1 to 3:3.

[0071] In one embodiment including any of the foregoing, the cathode active material is LiNi x Mn y Co z O2 (where x + y + z = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ z ≦ 1). In one embodiment including any of the foregoing, the cathode active material is LiNi x Mn y Co z O2 (where x is 0.8, y is 0.1, and z is 0.1). In one embodiment including any of the foregoing, the cathode active material is LiNi x Mny Co z O2 (where x is 0.6, y is 0.2, and z is 0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x is 0.5, y is 0.3, and z is 0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x is 1 / 3, y is 1 / 3, and z is 1 / 3). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.97, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.95, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.9, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.85, 0≦y≦0.2, and 0≦z≦0.2). In one embodiment including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.83, 0≦y≦0.2, and 0≦z≦0.2).

[0072] This specification also refers to 1) LiMPO4 (M=Fe, Ni, Co, Mn), Li x Tiy O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), and LiNi x Co y Al z 1) Cathode active material particles selected from O2 (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1), 2) a coating in contact with the cathode active material particles, the coating comprising lithium phosphate species, and at least about 60% of the surface area of ​​the cathode active material particles being in contact with the coating, 3) a solid electrolyte, and 4) lithium metal, lithium titanate (Li2TiO3, LTO), carbon / graphite (C), silicon (Si) / silicon oxide (SiO2). x Solid-state batteries are also described that include anode active materials selected from lithium (Li), zinc (Zn), aluminum (Al), magnesium (Mg), alloys thereof, and combinations thereof.

[0073] This specification also refers to 1) LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), or LiNi x Co y Al z1) Cathode active material particles selected from O2 (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1), 2) A coating in contact with the cathode active material particles, the coating comprising lithium phosphate species, which are reaction products of LiOEt and a phosphorus precursor, with a molar ratio of Li:P in the reaction mixture being approximately 3:1 to 1:3, and the lithium phosphate species being a product of heating at a temperature of approximately 250°C to 375°C, 3) A solid electrolyte, and 4) Lithium metal, lithium titanate (Li2TiO3, LTO), carbon / graphite (C), silicon (Si) / silicon oxide (SiO2). x Solid-state batteries comprising anode active materials selected from lithium (Li), zinc (Zn), aluminum (Al), magnesium (Mg), alloys thereof, and combinations thereof are also described. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 3:1 to 3:3.

[0074] In certain embodiments including any of the above, the cathode active material of the particles in the battery is LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0-8, y is 1-12, and z is 1-24), LiMn2O4, LiMn 2a Ni a Selected from O4 (where a is between 0 and 2), LiCoO2, Li(NiCoMn)O2, Li(NiCoAl)O2, or nickel-cobalt aluminum oxide. In certain embodiments including any of the above, the cathode active material in the battery is LiMPO4 (M=Fe, Ni, Co, Mn), Li x T iy O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a Selected from O4 (where a is between 0 and 2) or nickel-cobalt aluminum oxide.

[0075] In certain embodiments including any of the above, the cathode active material of the particles in the battery is MnO, Li x Mn2O4, Li x MnO2, Li x KiO2, Li x CoO2, LiNi (1-y) Co y O2, LiMn y Co (1-y) O2, Li x Mn (2-y) Ni y O4, Li x FePO4, Li x Fe (1-y) Mn y PO4, Li x The material is selected from CoPO4, Li7V2(PO4)3, Fe2(SO4)3, V2O5, or a combination thereof, and the conditions are 1≦x≦5 and 0≦y≦1.

[0076] In certain embodiments including any of the above, the cathode active material in the battery is LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), or LiNi x Co y Al z O2 (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1) is selected. In certain embodiments including any of the above, the cathode active material is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1). In a particular example, the cathode active material is LiNi x Mn y Co zO2 (where x is 0.8, y is 0.1, and z is 0.1). In some other specific examples, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 0.6, y is 0.2, and z is 0.2). In some other examples, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 0.5, y is 0.3, and z is 0.2). In another example, the coated cathode active material is LiNi x Mn y Co z O2 (where x is 1 / 3, y is 1 / 3, and z is 1 / 3). In certain embodiments, the coated cathode active material is selected from LiMn2O4, LiCoO2, Li(NiCoMn)O2, and Li(NiCoAl)O2.

[0077] In certain embodiments including any of the above, the cathode active material in the battery is LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), or LiNi x Co y Al z O2 is selected from (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1).

[0078] In certain embodiments including any of the above, the cathode active material in the battery is MnO, Li x Mn2O4, Li x MnO2, Li xKiO2, Li x CoO2, LiNi (1-y) Co y O2, LiMn y Co (1-y) O2, Li x Mn (2-y) Ni y O4, Li x FePO4, Li x Fe (1-y) Mn y PO4, Li x The material is selected from CoPO4, Li7V2(PO4)3, Fe2(SO4)3, V2O5, or a combination thereof, and the conditions are 1≦x≦5 and 0≦y≦1.

[0079] In one embodiment including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1). In one embodiment including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x is 0.8, y is 0.1, and z is 0.1). In one embodiment including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x is 0.6, y is 0.2, and z is 0.2). In one embodiment including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x is 0.5, y is 0.3, and z is 0.2). In certain embodiments including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.97, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material in the battery is LiNi x Mny Co z O2 (where x+y+z=1, 0.80≦x≦0.95, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.9, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.85, 0≦y≦0.2, and 0≦z≦0.2). In certain embodiments including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x+y+z=1, 0.80≦x≦0.83, 0≦y≦0.2, and 0≦z≦0.2).

[0080] In certain embodiments including any of the above, the cathode active material is a member of the NMC class of cathode active materials, for example, LiNiCoMnO2. In certain embodiments including any of the above, the cathode active material is a member of the LFP class of cathode active materials, for example, LiFePO4 / C. In certain embodiments including any of the above, the cathode active material is a member of the LNMO class of cathode active materials, for example, LiNi 0.5 Mn 1.5 O4 or LiNi 0.5 Mn 1.5 It is O2. In certain embodiments including any of the above, the cathode active material is a member of the NCA class of cathode active materials, for example, LiMn2O4. In certain embodiments including any of the above, the cathode active material is a member of the LMO class of cathode active materials, for example, LiMn2O4. In certain embodiments including any of the above, the cathode active material is a member of the LCO class of cathode active materials, for example, LiCoO2.

[0081] In some other embodiments, the cathode active material is manganese oxide (MnO), iron oxide, copper oxide, nickel oxide, lithium manganese-based composite oxide (e.g., Li x Mn2O4 or Li x MnO2), lithium nickel-based composite oxide (e.g., Li x NiO2), lithium cobalt-based composite oxide (e.g., Li x CoO2), lithium cobalt nickel oxide (LiNi 1-y Co y O2), lithium manganese cobalt-based composite oxide (e.g., LiMn y Co 1-y O2), spinel phase lithium manganese nickel-based composite oxide (e.g., Li x Mn 2-y Ni y O4), lithium phosphate having an olivine structure (e.g., Li x FePO4, Li x Fe 1-y Mn y PO4, Li x CoPO4), lithium phosphate having a NASICON-type structure (e.g., Li7V2(PO4)3), iron(III) sulfate (Fe2(SO4)3), or vanadium oxide (e.g., V2O5), or includes these. In some embodiments, x and y in these chemical formulas are within the ranges of 1 < x < 5 and 0 < y < 1. In some embodiments, the cathode active material is LiCoO2, Li x V2(PO4)3, LiNiPO4, and LiFePO4. In some embodiments, the cathode active material is doped LiCoO2 including La-doped LiCoO2, Al-doped LiCoO2, or a combination thereof. <00​​​​​​​​​​​x Mn y Co z O2 and (a)~(e): (a) x is 0.8, y is 0.1, and z is 0.1. (b) 0.80 ≤ x ≤ 0.97, 0 ≤ y ≤ 0.2, and 0 ≤ z ≤ 0.2, (c) 0.80 ≤ x ≤ 0.90, 0 ≤ y ≤ 0.2, and 0 ≤ z ≤ 0.2, (d) 0.80 ≤ x ≤ 0.85, 0 ≤ y ≤ 0.2, and 0 ≤ z ≤ 0.2, or (e) 0.80 ≤ x ≤ 0.83, 0 ≤ y ≤ 0.2, and 0 ≤ z ≤ 0.2 It is one of the following (where x, y, and z add up to 1).

[0083] In one embodiment including any of the above, the cathode active material in the battery is LiNi x Mn y Co z O2 (where x is 1 / 3, y is 1 / 3, and z is 1 / 3). In one embodiment including any of the above, the cathode active material in the battery is selected from LiMn2O4, LiCoO2, Li(NiCoMn)O2, or Li(NiCoAl)O2. In one embodiment including any of the above, the cathode active material is selected from LiMn2O4, LiCoO2, Li(NiCoMn)O2, or Li(NiCoAl)O2. In one embodiment including any of the above, the cathode active material is Li(NiCoMn)O2.

[0084] In some embodiments, the cathode active material is doped with zirconium. In some embodiments, the cathode active material is Zr-doped LiNi x Mn y Co z O2 (where x+y+z=1, 0.8≦x≦1, 0≦y≦1, and 0≦z≦1, x+y+z=1). In some embodiments, the cathode active material is Zr-doped LiNi x Mn y Co zO2 (where x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2, x+y+z=1). Unless otherwise explicitly stated, the variables used herein are selected such that the chemical formula is charge-neutral.

[0085] In some other examples, this specification describes batteries comprising a solid cathode, solid separator, and anode as described herein. In certain embodiments, a solid cathode comprising a coated cathode active material described herein is described. In certain embodiments including any of the above, the solid cathode comprises a solid electrolyte selected from the group consisting of Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-Li3MO4, Li2S-SiS2-Li3MO3, Li2S-P2S5-LiI, and LATS (where M is a member selected from the group consisting of Si, P, Ge, B, Al, Ga, and In). In certain embodiments including any of the foregoing, the solid cathode comprises the cathode liquid described in PCT / US22 / 51433, International Patent Application Publication No. 2023121838, filed November 11, 2022, which is incorporated herein by reference. In certain embodiments, the cathode solution comprises a lithium salt and, independently in each case, at least two carbon atoms, each containing at least one sulfur (S) ring atom and possibly substituted with 1 to 6 substituents. 3-10 It includes heterocyclic molecules. In some embodiments, including any of the above, C 3-10 A heterocyclic molecule is a molecule with the following formula:

[0086] [ka] (Here, R 1(The compound is selected from the group consisting of polyethylene glycol (PEG), =O, SO2, -CF3, -CH2F, CHF2, -NO2, -NO3, -NH3, -CH3, PO4, PO3, BO3, -CN, and combinations thereof, where the subscript n is an integer from 0 to 8.) In some embodiments, including any of the above, C 3-10 A heterocyclic molecule is the molecule of formula (III).

[0087] [ka] In some embodiments, including any of the above, C 3-10 Heterocyclic molecules contain at least one sulfur (S) ring atom. In some embodiments, including any of the above, C 3-10 A heterocyclic molecule contains at least one sulfur (S) ring atom and one oxygen (O) ring atom. In some embodiments, including any of the above, at least one C 3-10 The heterocyclic molecule is selected from the group consisting of ethylene sulfite, sulfolane, and combinations thereof. In some embodiments, including any of the above, at least one C 3-10 The heterocyclic molecule is selected from ethylene sulfite. In some embodiments, including any of the above, at least one C 3-10 Heterocyclic molecules are selected from sulfolanes. In some embodiments, including any of the above, the lithium salt is selected from the group consisting of LiPF6, lithium bis(oxalate)boric acid (LiBOB), lithium bis(perfluoroethanesulfonyl)imide (LIBETI), bis(trifluoromethane)sulfonimide (LiTFSI), LiBF4, LiClO4, LiAsF6, lithium bis(fluorosulfonyl)imide (LiFSI), LiF, LiCl, LiBr, LiI, and combinations thereof. In some embodiments, including any of the above, the lithium salt is present at a concentration of about 0.5 M to about 5.0 M. In some embodiments, including any of the above, the lithium salt is present at a concentration of about 0.5 M to about 2.5 M. In some other embodiments, including any of the above, the lithium salt is present at a concentration of about 0.5 M to about 2.0 M.

[0088] In some embodiments, including any of the above, the cathode liquid is two C 3-10 Contains a heterocyclic molecule and one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 20:80 volume / volume (v / v) ~ 80:20 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 15:85 volume / volume (v / v) ~ 85:15 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 20:80 volume / volume (v / v) ~ 80:20 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 25:75 volume / volume (v / v) ~ 75:25 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 30:70 volume / volume (v / v) ~ 70:30 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 35:65 volume / volume (v / v) ~ 65:35 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 40:60 volume / volume (v / v) ~ 60:40 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10The ratio of heterocyclic molecules is 45:55 volume / volume (v / v) ~ 55:45 v / v. In some embodiments, including any of the above, one C 3-10 Heterocyclic molecule vs other C 3-10 The ratio of heterocyclic molecules is 50:50 volume / volume (v / v).

[0089] In some embodiments, including any of the above, the sulfolane:(ethylene sulfite) ratio is 30:70v / v to 50:50v / v. In some embodiments, including any of the above, the sulfolane:(ethylene sulfite) ratio is 30:70v / v. In some embodiments, including any of the above, the sulfolane:(ethylene sulfite) ratio is 50:50v / v. In some embodiments, including any of the above, the sulfolane:(ethylene sulfite) ratio is 10:90v / v to 90:10v / v. In some embodiments, including any of the above, the sulfolane:(ethylene sulfite) ratio is 10:90v / v to 50:50v / v.

[0090] In some embodiments, including any of the above, the cathode solution may also contain tris(trimethylsilyl)phosphite (TTSPi), tris(trimethylsilyl)phosphate (TTSPa), trimethoxyboroxine (C3H9B3O6, TMOBX), vinylene carbonate (VC), vinylethylene carbonate (VEC), methylene methane disulfonate (MMDS), propane-1-ene-1,3-sultone (PES), fluoroethylene carbonate (F This also includes additives selected from the group consisting of EC, LiTFSi, LiBOB, succinonitrile, trimethylene sulfate (TMS), triallyl phosphate (TAP), tris(trimethylsilyl) borate (TMSB), tris(pentafluorophenyl)borane (TPFPB), methyl acetate, tris(trimethylsilyl) acetate, tris(trimethylsilyl) pyridine, tris(trimethylsilyl) methacrylate, tris(2,2,2-trifluoroethyl) phosphite, tris(2,2,2-trifluoroethyl) borate, and combinations thereof. In some embodiments, including any of the above, the additive is TTSPa. In some embodiments, including any of the above, the additive is TTSPa. In some embodiments, including any of the above, the additive is a combination of TTSPa and TTSPa. In some embodiments, the cathode liquid is in contact with a solid separator containing lithium-filled garnet. In some embodiments, the solid separator is a thin film.

[0091] Method for manufacturing This specification describes a method for producing cathode active material particles coated with lithium phosphate species, comprising: 1) coating cathode active material particles with a reaction mixture comprising a lithium precursor, a phosphorus precursor, and a solvent, wherein the molar ratio of Li:P in the reaction mixture is approximately 3:1 to 1:3; 2) removing the solvent from the reaction mixture; and 3) heating the cathode active material particles at a temperature of approximately 250°C to 375°C under dry air conditions or an O2 atmosphere to form cathode active material particles coated with lithium phosphate species.

[0092] This specification describes a method for producing cathode active material particles coated with lithium phosphate species, comprising the following steps: 1) coating cathode active material particles with a solution of a) a lithium precursor and b) a phosphorus precursor, wherein the molar ratio of Li:P in the reaction mixture is about 3:1 to 1:3; 2) removing the solvent from the solution to provide cathode active material particles coated with lithium phosphate species; and 3) heating the cathode active material particles at a temperature of about 150°C to 375°C under dry air conditions or an O2 atmosphere to form cathode active material particles coated with lithium phosphate species. In some embodiments, the temperature is approximately 150°C to 350°C. In some embodiments, the temperature is approximately 150°C to 300°C. In some embodiments, the temperature is approximately 150°C to 250°C. In some embodiments, the temperature is approximately 250°C to 375°C. In some embodiments, the temperature is approximately 350°C to 375°C. In some embodiments, the temperature is approximately 300°C to 350°C. In some embodiments, the temperature is approximately 250°C to 300°C. In some embodiments, the temperature is approximately 375°C. In some embodiments, the temperature is approximately 350°C. In some embodiments, the temperature is approximately 300°C. In some embodiments, the temperature is approximately 250°C. In some embodiments, the temperature is approximately 150°C.

[0093] In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 3:1 to 3:3. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 3:1. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 3:1.5. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 3:2. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 1:3. In some embodiments, the molar ratio of Li:P in the reaction mixture is approximately 2:3. In some embodiments, heating is performed in a controlled atmosphere. In some embodiments, the controlled atmosphere is O2, Ar, N2, H2, H2O 、 or a combination thereof. In some embodiments, the controlled atmosphere includes an O2 atmosphere.

[0094] In some embodiments, the lithium phosphate species is of the formula Li x P y O z The compound comprises (where 1.0 ≤ x ≤ 4.0, 0 ≤ y ≤ 2.0, and 2.0 ≤ z ≤ 7.0), and the formula is charge-neutral. In some embodiments, the lithium phosphate species is given by formula Li x P y O z The compound (where 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, and 2.0 ≤ z ≤ 3.7) is included, and the formula is charge-neutral.

[0095] In some embodiments, the lithium phosphate species is Li3PO4, LiPO3, Li4P2O7, a mixture of Li4P2O7 and Li3PO4 (i.e., Li4P2O7 / Li3PO4), a mixture of Li4P2O7 and LiPO3 (i.e., Li4P2O7 / LiPO3), an organolithium phosphate, or a combination thereof. In some embodiments, the lithium phosphate species is Li3PO4. In some embodiments, the lithium phosphate species is LiPO3. In some embodiments, the lithium phosphate species is Li4P2O7 / Li3PO4. In some embodiments, the lithium phosphate species is Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is an organolithium phosphate. In some embodiments, the organolithium phosphate is lithium diethyl phosphate, lithium dimethyl phosphate, lithium diisopropyl phosphate, lithium ethyl methyl phosphate, lithium ethyl isopropyl phosphate, lithium methyl isopropyl phosphate, dilithium methyl phosphate, dilithium ethyl phosphate, dilithium isopropyl phosphate, or a combination thereof.

[0096] In some embodiments, the lithium phosphate species is crystalline, amorphous, or a combination thereof. In some embodiments, the lithium phosphate species is crystalline. In some embodiments, the lithium phosphate species is amorphous. In some embodiments, the lithium phosphate species is both crystalline and amorphous. In some embodiments, the lithium phosphate species is crystalline Li3PO4. In some embodiments, the lithium phosphate species is amorphous Li3PO4. In some embodiments, the lithium phosphate species is crystalline Li3PO4 and amorphous Li3PO4. In some embodiments, the lithium phosphate species is crystalline LiPO3. In some embodiments, the lithium phosphate species is amorphous LiPO3. In some embodiments, the lithium phosphate species is crystalline LiPO3 and amorphous LiPO3. In some embodiments, the lithium phosphate species is crystalline Li4P2O7. In some embodiments, the lithium phosphate species is amorphous Li4P2O7. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 and amorphous Li4P2O7. In some embodiments, the lithium phosphate species is a mixture of crystalline Li4P2O7 and crystalline Li3PO4 (i.e., crystalline Li4P2O7 / Li3PO4). In some embodiments, the lithium phosphate species is a mixture of amorphous Li4P2O7 and amorphous Li3PO4 (i.e., amorphous Li4P2O7 / Li3PO4). In some embodiments, the lithium phosphate species is a mixture of crystalline Li4P2O7 / Li3PO4 and amorphous Li4P2O7 / Li3PO4. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is amorphous Li4P2O7 / LiPO3. In some embodiments, the lithium phosphate species is crystalline Li4P2O7 / LiPO3 and amorphous Li4P2O7 / LiPO3.

[0097] In some embodiments, the phosphorus precursor is selected from P2O5, H3PO4, (NH4)3PO4, (NH3)3PO4, diethyl phosphate, dimethyl phosphate, and combinations thereof. In some embodiments, the lithium precursor is selected from lithium hydroxide (LiOH), lithium ethoxide (LiOEt), lithium methoxide (LiOMe), metallic lithium, or combinations thereof. In some embodiments, the phosphorus precursor is a sol-gel precursor such as a phosphorus alkoxide precursor. In some embodiments, the phosphorus precursor is P2O5. In some embodiments, the lithium precursor is LiOH. In some embodiments, the lithium precursor is LiOEt.

[0098] In some embodiments, the phosphorus precursor is P2O5 and the lithium precursor is LiOH. In some embodiments, the phosphorus precursor is P2O5 and the lithium precursor is LiOEt. In some embodiments, the LiOH source includes, but is not limited to, LiOH. In some embodiments, the LiOH source includes, but is not limited to, a lithium-containing compound soluble in alcohol, such as methanol or ethanol.

[0099] In some embodiments, heating is at approximately 150°C for at least 10 minutes. In some embodiments, heating is at approximately 150°C for at least 30 minutes. In some embodiments, heating is at approximately 150°C for about 1 hour. In some embodiments, heating is at approximately 150°C for about 1.5 hours. In some embodiments, heating is at approximately 150°C for up to 5 hours. In some embodiments, heating is at approximately 250°C for at least 10 minutes. In some embodiments, heating is at approximately 250°C for at least 30 minutes. In some embodiments, heating is at approximately 250°C for about 1 hour. In some embodiments, heating is at approximately 250°C for about 1.5 hours. In some embodiments, heating is at approximately 250°C for up to 5 hours. In some embodiments, heating is at approximately 300°C for at least 10 minutes. In some embodiments, heating is at approximately 300°C for at least 30 minutes. In some embodiments, heating is at approximately 300°C for about 1 hour. In some embodiments, heating is at approximately 300°C for about 1.5 hours. In some embodiments, heating is at approximately 300°C for up to 5 hours. In some embodiments, heating is at approximately 350°C for at least 10 minutes. In some embodiments, heating is at approximately 350°C for at least 30 minutes. In some embodiments, heating is at approximately 350°C for about 1 hour. In some embodiments, heating is at approximately 350°C for about 1.5 hours. In some embodiments, heating is at approximately 350°C for up to 5 hours. In some embodiments, heating is at approximately 375°C for at least 10 minutes. In some embodiments, heating is at approximately 375°C for at least 30 minutes. In some embodiments, heating is at approximately 375°C for about 1 hour. In some embodiments, heating is at approximately 375°C for about 1.5 hours. In some embodiments, heating is at approximately 375°C for up to 5 hours.

[0100] In some embodiments, the solvent is an alcohol, including but not limited to methanol or ethanol.

[0101] In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0102] In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:1.5 in the reaction mixture, and the lithium phosphate species is a product obtained by heating at approximately 375°C.

[0103] In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 3:2 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0104] In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 2:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0105] In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 150°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 250°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 300°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 350°C. In some embodiments, the lithium phosphate species is a reaction product of LiOEt and a phosphorus precursor, with a Li:P molar ratio of approximately 1:3 in the reaction mixture, and the lithium phosphate species is produced by heating at approximately 375°C.

[0106] In some embodiments, the lithium phosphate species is the reaction product of 0.0074 mol of LiOEt and 0.0025 mol of phosphorus precursor. In some embodiments, the lithium phosphate species is the reaction product of 0.0147 mol of LiOEt and 0.0049 mol of phosphorus precursor. In some embodiments, the lithium phosphate species is the reaction product of 0.0294 mol of LiOEt and 0.0980 mol of phosphorus precursor. Furthermore, coated active materials can be formed using any suitable method for forming a coating on the active material. Common techniques for preparing coated active materials include, but are not limited to, wet methods using a rotary evaporator to remove the solvent from a coating solution containing active material particles; spray drying methods in which a solution of coating precursor and active material is atomized through a spray nozzle by a compressed gas stream and the resulting aerosol is dried; dry coating methods in which a solid powder of the coating precursor is combined with the active material to form a mixture of the two; mechanofusion mixer methods used to coat the active material using high-energy grinding; and atomic layer deposition (ALD), gas phase coating deposition techniques, or fluidized bed reactors. Other techniques for forming coated active materials include sputter deposition and laser ablation.

[0107] For example, one method for coating with an active material is shown in Figure 1. As shown in Figure 1, air is treated by passing it through a heater 102 and a HEPA filter 103 using a fan 101. This treated air enters a drying chamber 104. The drying chamber is also connected to a supply pump 105. A liquid solution containing the active material and coating precursor is fed into the drying chamber 104 through the supply pump 105, where it is atomized through a spray nozzle 106 using a carrier gas fed into the drying chamber through an inlet 107. The resulting droplets 108 are dried in the drying chamber 104. The dried material is then sent to a cyclone 109, where the coated active material is collected in a container 110. The dried powder product is filtered through a fine powder filter 111. In some examples, an air pulse is used via an input 112. The air is filtered through a second HEPA filter 103.

[0108] Non-limiting embodiment This disclosure provides at least the following non-limiting embodiments: (a) Cathode active material particles, A coating in contact with cathode active material particles, wherein the coating contains lithium phosphate species, and at least about 60% of the surface area of ​​the cathode active material particles, as determined by TEM analysis, is in contact with the coating. A composition containing, (b) Cathode active material particles, A coating in contact with cathode active material particles, wherein the coating contains lithium phosphate species, the lithium phosphate species is a reaction product of a lithium precursor and a phosphorus precursor, the molar ratio of Li:P in the reaction mixture is about 3:1 to 1:3, and the lithium phosphate species is obtained by heating at a temperature of about 250°C to 375°C, and A composition containing, (c) The composition of (a), wherein at least about 65% of the surface area of ​​the cathode active material particles is in contact with the coating. (d) The composition of (a), wherein at least about 70% of the surface area of ​​the cathode active material particles is in contact with the coating. (e) The composition of (a), wherein at least about 75% of the surface area of ​​the cathode active material particles is in contact with the coating. (f) The composition of (a), wherein at least about 80% of the surface area of ​​the cathode active material particles is in contact with the coating. (g) The composition of (a), wherein at least about 85% of the surface area of ​​the cathode active material particles is in contact with the coating. (h) The composition of (a), wherein at least about 90% of the surface area of ​​the cathode active material particles is in contact with the coating. (i) The composition of (a), wherein at least about 95% of the surface area of ​​the cathode active material particles is in contact with the coating. (j) The composition of (a), wherein more than 95% of the surface area of ​​the cathode active material particles is in contact with the coating. (k) The composition of (a), wherein at least about 60% to 70% of the surface area of ​​the cathode active material particles is in contact with the coating. (l) The composition of (a), wherein at least about 70% to 80% of the surface area of ​​the cathode active material particles is in contact with the coating. (m) The composition of (a), wherein at least about 80% to 90% of the surface area of ​​the cathode active material particles is in contact with the coating. (n) The composition of (a), wherein at least about 90% to 95% of the surface area of ​​the cathode active material particles is in contact with the coating. (o) A composition of any one of embodiments (a) to (n), wherein the coating is amorphous. (p) A composition of any one of embodiments (a) to (o) in which the coating is crystalline, (q) Any one of the compositions of Embodiments (b) and (o) to (p), wherein the molar ratio of Li:P in the reaction mixture is approximately 3:1. (r) Any one of the compositions of Embodiments (b) and (o) to (p), wherein the molar ratio of Li:P in the reaction mixture is approximately 3:2. (s) A composition of any one of embodiments (b) and (o) to (p), wherein the molar ratio of Li:P in the reaction mixture is approximately 1:3. (t) A composition of any one of embodiments (b) and (o) to (p), wherein the molar ratio of Li:P in the reaction mixture is approximately 3:2. (u) A composition of any one of embodiments (b) and (o) to (p), wherein the heating temperature is approximately 250°C to 300°C. (v) Any one of the compositions of Embodiments (b) and (o) to (u), wherein the heating temperature is approximately 300°C to 350°C. (w) A composition of any one of embodiments (b) and (o) to (u), wherein the heating temperature is approximately 350°C to 375°C. (x) A composition of any one of embodiments (b) and (o) to (u), wherein the heating temperature is approximately 250°C. (y) A composition of any one of embodiments (b) and (o) to (u), wherein the heating temperature is approximately 300°C. (z) A composition of any one of embodiments (b) and (o) to (u), heated to approximately 375°C. (aa) A composition of any one of embodiments (b), (o) to (z), wherein the phosphorus precursor is selected from P2O5, H3PO4, (NH4)3PO4, and combinations thereof. (bb) Composition of embodiment (aa) in which the phosphorus precursor is P2O5 、 (cc) The lithium precursor is selected from LiOH, LiOEt, LiOMe, metallic lithium, and combinations thereof, in the compositions of embodiments (b), (o) to (z). (dd) A composition of embodiment (cc) in which the lithium precursor is LiOEt, (ee) A composition of any one of embodiments (a) to (dd), wherein the coating is lattice-matched with the cathode active material particles. (ff) A composition of embodiment (ee) having an amorphous surface coating, (gg) A composition of embodiment (ee) or (ff) wherein the coating has a crystalline surface, The cathode active material of the (hh) particles is LiMPO4 (M=Fe, Ni, Co, Mn), Li x Ti y O z (Here, x is 0 to 8, y is 1 to 12, and z is 1 to 24), LiMn 2a Ni a O4 (where a is between 0 and 2), nickel-cobalt aluminum oxide, LiNi x Mn y Co z O2(x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1), and LiNi x Co y Al z A composition selected from O2 (where x+y+z=1, and 0≦x≦1, 0≦y≦1, and 0≦z≦1), any one of embodiments (a) to (gg), (ii) The cathode active material of the particle is LiNi x Mn y Co z A composition of any one of embodiments (a) to (hh), where O2(x+y+z=1, 0≦x≦1, 0≦y≦1, and 0≦z≦1, where x+y+z=1), (jj) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2 (where x is 0.8, y is 0.1, and z is 0.1), (kk) Cathode active material is LiNix Mn y Co z The composition of embodiment (ii) is O2 (where x is 0.6, y is 0.2, and z is 0.2), (ll) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2 (where x is 0.5, y is 0.3, and z is 0.2), (mm) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2 (where x is 1 / 3, y is 1 / 3, and z is 1 / 3), (nn) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2(x+y+z=1, 0.80≦x≦0.97, 0≦y≦0.2, and 0≦z≦0.2), (oo) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2(x+y+z=1, 0.80≦x≦0.90, 0≦y≦0.2, and 0≦z≦0.2), (pp) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2(x+y+z=1, 0.80≦x≦0.85, 0≦y≦0.2, and 0≦z≦0.2), (qq) Cathode active material is LiNi x Mn y Co z The composition of embodiment (ii) is O2(x+y+z=1, 0.80≦x≦0.83, 0≦y≦0.2, and 0≦z≦0.2), (rr) The composition of embodiment (ii), wherein the cathode active material is Li(NiCoMn)O2. (ss) A composition of any one of embodiments (a) to (ii), wherein the cathode active material is selected from the group consisting of NMC class cathode active material, LFP class cathode active material, LNMO class cathode active material, NCA class cathode active material, LMO class cathode active material, and LCO class cathode active material. (tt) A composition having a continuous coating, any one of embodiments (a) to (ss), (uu) A composition of any one of embodiments (a) to (ss) in which the coating is discontinuous, (vv) A composition of any one of embodiments (a) to (uu) wherein the coating contains crystalline domains as measured by TEM analysis, (ww) A coating comprising any one of the compositions of embodiments (a) to (vv), wherein the coating contains amorphous domains as measured by TEM analysis. (xx) A coating comprising any one of the compositions of embodiments (a) to (ww), wherein the coating comprises crystalline and amorphous domains as measured by TEM analysis. (yy) A composition of embodiment (xx) in which crystalline domains are in contact with the cathode and amorphous domains are in contact with crystalline domains, (zz) A composition of any one of embodiments (a) to (xx), wherein the coating has a thickness T measured by TEM analysis and 1 nm ≤ T ≤ 20 nm, (aaa) A coating having a thickness T measured by TEM analysis, where 1 nm ≤ T ≤ 10 nm, one of any one of embodiments (a) to (xx), (bbb) A coating having a thickness T measured by TEM analysis, where 1 nm ≤ T ≤ 3 nm, one of any one of embodiments (a) to (xx), (ccc) Coating has a thickness T measured by TEM analysis and is less than 1 nm, one of the compositions of embodiments (a) to (xx), (ddd) Any one of the compositions of embodiments (a) to (xx), wherein the coating does not exceed a thickness detectable by TEM. A composition of any one of embodiments (a) to (ddd), wherein the (eee) coated crystalline domain is lattice-matched with the crystalline domain of the cathode active material as measured by TEM analysis. (fff) A composition of any one of embodiments (a) to (ddd) in which the coated crystalline domain is not lattice-matched with the crystalline domain of the cathode active material as measured by TEM analysis, (ggg) Coating further comprises carbonate, one of any one of embodiments (a) to (fff), A composition of any one of embodiments (a) to (ggg), further comprising a second coating in contact with the (hhh) coating, (iii) The composition of embodiment (hh) wherein the second coating has a chemical formula other than Li3PO4, (jjj) The composition of embodiment (iii), wherein the second coating has the following chemical formula: Li x Zr y O z (where 0≦x≦1.6, 0.2≦y≦1.0, and 2≦z≦1.2), Li x P y O z (Here, 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, and 2.0 ≤ z ≤ 3.7), Li x Zr y (PO4) z (Here, 0.05 ≤ x ≤ 1.5, 1 ≤ y ≤ 3, and 2.0 ≤ z ≤ 4.0), Li x C y O z (Here, 0.4 ≤ x ≤ 1.8, 0.1 ≤ y ≤ 1, and 1 ≤ z ≤ 1.8), Li x B y O z (Here, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, and 1.5 ≤ z ≤ 2.6), Li x In y Cl z (Here, 2≦x≦4, 0≦y≦2, and 5≦z≦7), Lix Zr y (PO4) z (Here, 0.05 ≤ x ≤ 1.5, 1 ≤ y ≤ 3, and 2.0 ≤ z ≤ 4.0), Li2CO3, Li3BO3, Li3B 11 O 18 , Li2ZrO3, Li3PO4, Li2SO4, LiNbO3, Li4Ti5O 12 , LiTi2(PO4)3, LiZr2(PO4)3, LiOH, LiF, Li4ZrF8, Li3Zr4F 19 Li3TiF6, LiAlF4, LiYF4, LiNbF6, ZrO2, Al2O3, TiO2, ZrF4, AlF3, TiF4, YF3, NbF5, and combinations thereof, (kkk) A method for producing any one of the compositions of Embodiments (a) to (ggg), comprising the following steps: 1) coating cathode active material particles with a solution of a) a lithium precursor and b) a phosphorus precursor, wherein the molar ratio of Li:P in the reaction mixture is approximately 3:1 to 1:3; 2) removing the solvent from the solution to provide a cathode coated with lithium phosphate species; and 3) heating the cathode active material under dry air conditions at a temperature of approximately 250°C to 375°C to form cathode active material particles coated with lithium phosphate species. (lll) The method of embodiment (kkk) in which the phosphorus precursor is P2O5, (mmm) The heating is carried out at a temperature of approximately 375°C, according to the method of embodiment (kkk) or (lll), and (nnn) A method according to embodiment (kkk) or (lll), wherein heating is carried out at a temperature of approximately 250°C. [Examples]

[0109] Unless otherwise specified, reagents, chemicals, and materials were purchased commercially. The lithium nickel cobalt manganese oxide (NMC) used in the examples is LiNi unless otherwise specified. 0.84 Co 0.09 Mn 0.07 O2, LiLiLi 0.88 Co 0.11 Mn0.01 O2, or LiNi 0.89 Co 0.8 Mn 0.03 It was O2.

[0110] (Example 1) Preparation of coated NMC Sixteen types of NMC cathode active materials with attached lithium phosphate species were prepared by the following method. The elemental molar ratio of the starting material, the amount of the starting material, and the heating temperature for each cathode are shown in Table 1.

[0111] [Table 1]

[0112] Coating Procedure 1 Step 1: Solutions were prepared by mixing LiOEt and P2O5 stock solutions in an argon-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm) with ethanol (Sigma-A) at 25°C. Step 2: Coating Step Lithium nickel cobalt manganese oxide (NMC) powder was added to the solution prepared in Step 1 and stirred for 1.5 hours. After stirring, the powder was dried at 65°C using a rotary evaporator to remove the solvent. Step 3: Heating Step The powder obtained in Step 2 was heated in an O2 atmosphere at the temperature shown in Table 1 for 1 hour. This yielded a coated cathode material. The coated cathode was stored in a dry atmosphere (dp < -50°C).

[0113] Coating procedure 2 Step 1: A solution was prepared by mixing lithium nickel cobalt manganese oxide (NMC) powder in ethanol (Sigma-A) in an argon-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm) at 25°C. Step 2: Coating Step Separately, two solutions were prepared by mixing stock LiOEt in ethanol and stock P2O5 in ethanol at 25°C in an argon-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm). The LiOEt solution was added dropwise to the NMC solution from Step 1 over 5 to 10 minutes. After the complete addition of LiOEt, the P2O5 solution was added dropwise to the NMC solution from Step 1 over 5 to 90 minutes. The resulting solution was stirred for 1.5 hours. After stirring, the powder was dried at 65°C using a rotary evaporator to remove the solvent. Step 3: Heating Step The powder obtained in Step 2 was heated in an O2 atmosphere at the temperature shown in Table 1 for 1 hour. This yielded a coated cathode material. The coated cathode was stored in a dry atmosphere (dp < -50°C).

[0114] (Example 2) Area Resistivity (ASR) Test The cathode electrode was prepared by mixing 2% Super C65, 2% Kynar® HSV, and 96% by mass of NMC in NMP (n-methylpyrrolidone). After mixing and degassing, the slurry was cast onto aluminum foil using a doctor blade, and the dried material was 28 mg / cm³. 2 The thickness was adjusted to achieve the desired result. The electrodes were dried using NMP at 120°C for 8 hours. The electrodes were calendered to a thickness that resulted in a porosity of 25% or 35% by volume, as measured by a scanning electron microscope. An 8mm diameter cathode electrode disc was punched out from the cathode electrode sheet.

[0115] A cell was assembled using a lithium-filled garnet separator, a lithium-free lithium metal anode, and the above-mentioned cathode electrode. "Lithium-free" means the cell was assembled in a discharged state. Before assembling the cell, the cathode electrode was immersed in ESS cathode solution mixture (70:30 v / v% ethylene sulfite:sulfolane + 1.4 M LiBF4 or 85:15 v / v% ethylene sulfite:sulfolane + 1.7 M LiBF4:LiTFSI (80:20)). After immersion, excess electrolyte was removed by lightly tapping, and then 0.5-3 μL of the excess electrolyte was added to the cathode-separator interface using a pipette. The tabbed anode current collector foil was placed in contact with the anode side of the separator, and the tabbed cathode current collector foil was placed in contact with the Al foil on the back of the cathode electrode. The cell was sealed with a pouch, and the tabs protruded from the cell, allowing for electrical connection to each electrode. The results are shown in Figure 2. Lithium phosphate coating significantly improved the increase in ASR up to 3 months after HTHV. Furthermore, as shown in Figure 8, the capacity increased and did not decrease up to 3 months after HTHV. Each data point in Figures 3A-3B, 4A-4B, 5A-5B, 6A-6B, and 7A-7B represents the average value of multiple experiments. The later figures in each set include the average values ​​of more experiments, and Figures 5B, 6B, and 7B include data from longer time periods. Additional ASR tests were conducted to investigate the effects of cathode heating temperature, the Li-to-P ratio of the starting material during coating, and the amount of starting material during coating. The effects of heating temperature are shown in Figures 3A-3B and 4A-4B. The median change was measured for battery cells fabricated using cathodes heated at 150°C, 250°C, 375°C, 500°C, and 650°C over 28 days. These cells were fabricated with initial Li-to-P ratios of 3:2 (cathodes 1 and 3 in Table 1) and 3:1 (cathodes 7-10 in Table 1). As shown in Figures 3A-3B, after 28 days, battery cells fabricated with cathodes heated at 250°C and 375°C with an initial Li-to-P ratio of 3:1 showed the smallest median change. The median change was similar between the two temperatures. Each data point represents the average value of at least 30 experiments in Figure 3A and at least 60 experiments in Figure 3B. Figures 4A-4B show the change in ASR over 175 days for cathodes heated at 250°C and 375°C with an initial Li-to-P ratio of 3:2. Each data point represents the average value of at least 5 experiments in Figure 4A and at least 50 experiments in Figure 4B. As shown in Figures 4A-4B, surprisingly, after 175 days, the battery cell fabricated with a cathode heated at 250°C showed a smaller change in ASR than the battery cell fabricated with a cathode heated at 375°C.

[0116] To investigate the effect of the Li:P ratio of the starting materials, battery cells were fabricated using cathodes 1, 3, 7, and 8 from Table 1, and the test results are shown in Figures 5A and 5B. Each data point represents the average value of at least 5 experiments in Figure 5A and the average value of at least 40 experiments in Figure 5B. Furthermore, Figure 5B includes ASR tests up to 178 days. Battery cells fabricated with cathodes coated with a Li:P ratio of 3:2 showed lower ASR changes than battery cells fabricated with cathodes coated with a Li:P ratio of 3:1, regardless of the heating temperature. Of the two cathodes coated with a Li:P ratio of 3:2, the cathode heated at 250°C showed a smaller change in ASR than the cathode heated at 375°C. To investigate the effect of the amount of starting material, three cathodes were prepared by varying the amounts of LiOEt and P2O5, resulting in a Li:P ratio of 3:2. These cathodes were then heated at 250°C. Battery cells fabricated with cathodes 1, 4, and 6 were prepared and tested, and the results are shown in Figures 6A and 6B. Each data point represents the average value of at least 5 experiments in Figure 6A, and the average value of at least 20 experiments in Figure 6B. Furthermore, Figure 6B includes ASR testing up to 178 days. Of the three cathodes, cathode 1 showed the smallest change in ASR from the initial value.

[0117] Finally, as shown in Figures 7A-7B, the battery cells fabricated with cathodes 1 and 8 were compared with battery cells fabricated with a cathode (cathode 16) prepared with LiOEt and P2O5 (Li:P ratio of 3:3) and heated at a temperature of 250°C. Each data point represents the average value of at least 5 experiments in Figure 7A and the average value of at least 40 experiments in Figure 6B. Furthermore, Figure 6B includes ASR testing up to 178 days. The battery cell fabricated with cathode 1 (Li:P ratio of 3:2) showed the best performance. These studies demonstrate that even slight changes in the amount and ratio of starting materials can affect ASR. It was not predicted that cathode 1 would perform better than the other cathodes in Table 1, which were fabricated using starting materials with a Li:P ratio of 3:2. Nor was it predicted that changing the Li:P ratio to 3:1 or 3:3 would negatively impact ASR.

[0118] (Example 3) Gas generation test Cells containing the cathodes shown in Table 1 were prepared in the same manner as in Examples 1 and 2. The cells were mounted on a strain gauge and immersed in a solution of potassium formate and water. The cells were maintained at a voltage of 4.25 V for two days. Gas generation in the cells was immediately represented as the difference between the measured total volume change and the volume change due to lithium plating.

[0119] The results are shown in Figure 9. Compared to cells made with uncoated cathodes, cells made with lithium phosphate coated cathodes (cathodes 1, 7, and 12) showed reduced gas generation after 2 days. Furthermore, a battery cell made with a cathode coated with a starting material with a Li:P ratio of 3:2 and heated at 250°C (cathode 1) showed less gas generation after 2 days compared to a cathode coated with a Li:P ratio of 3:1.5 and heated at 250°C (cathode 12), and a cathode coated with a Li:P ratio of 3:1 and heated at 375°C (cathode 7).

[0120] (Example 4) TEM (Transmission Electron Microscopy) Analysis NMC coated with lithium phosphate was prepared for TEM measurement using a Ga ion source focused ion beam (nanoDUE'T NB5000, Hitachi High-Tech Corporation). To protect the material surface from the Ga ion beam, multiple protective layers were formed before sampling; first, a metal layer was formed using a plasma coater, followed by a carbon protective layer and a tungsten layer, formed using high-vacuum evaporation and a focused ion beam, respectively. Thin section sampling was performed using the focused ion beam. The prepared samples were measured by TEM. TEM images of lithium phosphate-coated NMCs were obtained using a field emission electron microscope (JEM-2100F, JEOL). The acceleration voltage was set to 200 kV. The electron beam radius was set to approximately 0.7–1 nm. Figures 10-11 show different particles of the same sample. The coating in Figures 10-11 has a Li:P ratio of 3:2 and was heated at 250°C, while the coating in Figures 12-13 has a Li:P ratio of 3:1 and was heated at 375°C. In Figure 10, the coating thickness is approximately 2.5 nm, while in Figure 11, the coating thickness is 11.5–15.9 nm. In both images, the lithium phosphate coating is amorphous. Figure 12 is a TEM image of NMC coated with lithium phosphate species heated at 375°C, where the lithium phosphate species coating is crystalline. Figure 13 is a TEM image of NMC coated with lithium phosphate species, where the coating is discontinuous.

[0121] (Example 5) XPS (X-ray photoelectron spectroscopy) analysis NMCs having coatings 1, 7, 8, 10, 12, 13, and 14 were introduced into an XPS system (Thermo Fisher Scientific K-Alpha) under a dry atmosphere (-50°C). XPS analysis was performed using a monochromator-equipped microfocus Al-Ka as the X-ray source at a pressure of 10 -8 The analysis was performed using Torr. The diameter of the analysis area was 400 mm. The XPS spectrum was fitted to the background spectrum using a Gaussian / Laurentian product peak shape model. SMART-type background removal was used for peak fitting. Quantification was performed using sensitivity coefficients provided by the Avantage library. The results are shown in Table 2. Zirconium (Zr) is present as a dopant in the NMC core.

[0122] [Table 2]

[0123] [Table 3]

[0124] The embodiments and examples described above are illustrative and not limiting. Those skilled in the art will be able to recognize and confirm numerous equivalents of certain compounds, materials, and procedures through ordinary experimentation. All such equivalents are considered to be included within the scope of the appended claims and are encompassed within the claims.

Claims

1. A method for producing cathode active material particles coated with lithium phosphate species, 1) A step of coating cathode active material particles with a reaction mixture containing a lithium precursor, a phosphorus precursor, and a solvent, wherein the molar ratio of Li:P in the reaction mixture is about 3:1 to 1:

3. 2) A step of removing the solvent from the reaction mixture, 3) The cathode active material particles are subjected to dry air conditions or O 2 A process of heating at a temperature of approximately 250°C to 375°C under atmospheric conditions to form cathode active material particles coated with lithium phosphate species. Methods that include...

2. The method according to claim 1, comprising the step of heating the cathode active material to about 250°C.

3. The method according to claim 1, further comprising the step of heating the cathode active material to approximately 300°C.

4. The method according to claim 1, further comprising the step of heating the cathode active material to approximately 350°C.

5. The method according to claim 1, further comprising the step of heating the cathode active material to approximately 375°C.

6. The method according to any one of claims 1 to 5, wherein the molar ratio of Li:P in the reaction mixture is about 3:

1.

7. The method according to any one of claims 1 to 5, wherein the molar ratio of Li:P in the reaction mixture is about 3:

2.

8. The method according to any one of claims 1 to 5, wherein the molar ratio of Li:P in the reaction mixture is about 1:

3.

9. The method according to any one of claims 1 to 5, wherein the molar ratio of Li:P in the reaction mixture is about 2:

3.

10. The method according to any one of claims 1 to 9, wherein the lithium precursor is selected from LiOH, LiOEt, LiOMe, metallic lithium, or a combination thereof.

11. The method according to claim 10, wherein the lithium precursor is LiOEt.

12. The phosphorus precursor is P 2 O 5 H 3 PO 4 , (NH 4 ) 3 PO 4 The method according to any one of claims 1 to 9, or a combination thereof.

13. wherein the phosphorus precursor is P 2 O 5 The method according to claim 12

14. The lithium phosphate species is Li 3 PO 4 LiPO 3 Li 4 P 2 O 7 Li 4 P 2 O 7 / Li 3 PO 4 Li 4 P 2 O 7 / LiPO 3 The method according to any one of claims 1 to 13, wherein the material is lithium organophosphate, or a combination thereof.

15. A composition comprising cathode active material particles and a coating in contact with the cathode active material particles, wherein the coating comprises a lithium phosphate species, and the cathode active material particles are coated using a reaction mixture comprising a lithium precursor and a phosphorus precursor, with a Li:P molar ratio of about 3:1 to 1:3, at a temperature of about 250°C to 375°C.

16. The composition according to claim 15, wherein the molar ratio of Li:P in the reaction mixture is about 3:

1.

17. The composition according to claim 15, wherein the molar ratio of Li:P in the reaction mixture is about 3:

2.

18. The composition according to claim 15, wherein the molar ratio of Li:P in the reaction mixture is about 1:

3.

19. The composition according to claim 15, wherein the molar ratio of Li:P in the reaction mixture is about 2:

3.

20. The phosphorus precursor is P 2 O 5 H 3 PO 4 , (NH 4 ) 3 PO 4 A composition according to any one of claims 15 to 19, or selected from a combination thereof.

21. The phosphorus precursor is P 2 O 5 The composition according to claim 20.

22. The composition according to any one of claims 15 to 21, wherein the coating comprises crystalline domains measured by TEM analysis.

23. The composition according to any one of claims 15 to 22, wherein the coating comprises amorphous domains measured by TEM analysis.

24. The composition according to any one of claims 15 to 23, wherein the coating comprises crystalline domains and amorphous domains as measured by TEM analysis.

25. The composition according to claim 24, wherein the crystalline domain is in contact with the cathode active material.

26. The composition according to claim 24, wherein the amorphous domain is in contact with the cathode active material.

27. The composition according to any one of claims 15 to 26, wherein the coating is continuous.

28. The composition according to any one of claims 15 to 27, wherein the coating is discontinuous.

29. The composition according to any one of claims 15 to 28, wherein the coating has a thickness T of about 1 nm ≤ T ≤ 20 nm as measured by TEM analysis.

30. The composition according to any one of claims 15 to 29, wherein the coating has a thickness T of about 1 nm ≤ T ≤ 10 nm as measured by TEM analysis.

31. The composition according to any one of claims 15 to 30, wherein the coating has a thickness T of about 1 nm ≤ T ≤ 3 nm as measured by TEM analysis.

32. The cathode active material of the aforementioned particles is LiMPO 4 (M=Fe, Ni, Co, Mn), Li x Fe (1-y) Mn y PO 4 (Here, 1 ≤ x ≤ 5 and 0 ≤ y ≤ 1), Li x Ti y O z (Here, x is 0-8, y is 1-12, z is 1-24), LiMn 2a Ni a O 4 (Here, a is 0 to 2), nickel cobalt aluminum oxide, LiNi x Mn y Co z O 2 (x + y + z = 1, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1), or LiNi x Co y Al z O 2 A composition according to any one of claims 15 to 31, selected from (where x + y + z = 1, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1).

33. The cathode active material is LiNi x Mn y Co z O 2 The composition according to any one of claims 15 to 32, wherein (x + y + z = 1, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, x + y + z = 1).

34. The cathode active material is LiNi x Mn y Co z O 2 The composition according to claim 33, wherein any of (a) to (d). (a) 0.80≦x≦0.97, 0≦y≦0.2, 0≦z≦0.2, (b) 0.80≦x≦0.90, 0≦y≦0.2, 0≦z≦0.2, (c) 0.80≦x≦0.85, 0≦y≦0.2, 0≦z≦0.2, (d) 0.80≦x≦0.83, 0≦y≦0.2, 0≦z≦0.2 (Here, x + y + z = 1)

35. The composition according to any one of claims 1 to 33, further comprising a second coating in contact with the aforementioned coating.

36. The second coating is Li 3 PO 4 The composition according to claim 35, having a chemical formula other than the one specified.

37. The second coating has the chemical formula: Li x Zr y O z (Here, 0 ≤ x ≤ 1.6, 0.2 ≤ y ≤ 1.0, 2 ≤ z ≤ 1.2) Li x P y O z (Here, 0.6 ≤ x ≤ 1.5, 0.5 ≤ y ≤ 1.4, 2.0 ≤ z ≤ 3.7) Li x Zr y (PO 4 ) z (Here, 0.05 ≤ x ≤ 1.5, 1 ≤ y ≤ 3, 2.0 ≤ z ≤ 4.0) Li x C y O z (Here, 0.4 ≤ x ≤ 1.8, 0.1 ≤ y ≤ 1, 1 ≤ z ≤ 1.8) Li x B y O z (Here, 0.2 ≤ x ≤ 0.75, 0.5 ≤ y ≤ 1.6, 1.5 ≤ z ≤ 2.6) Li x In y Cl z (Here, 2 ≤ x ≤ 4, 0 ≤ y ≤ 2, 5 ≤ z ≤ 7), Li x Zr y (PO 4 ) z (where 0.05 ≤ x ≤ 1.5, 1 ≤ y ≤ 3, 2.0 ≤ z ≤ 4.0), or any combination thereof. The composition according to claim 35, having the following characteristics.

38. The aforementioned coating has the chemical formula: Li 2 CO 3 、Li 3 BO 3 、Li 3 B 11 O 18 、Li 2 ZrO 3 、Li 3 PO 4 、Li 2 SO 4 、LiNbO 3 、Li 4 Ti 5 O 12 、LiTi 2 (PO 4 ) 3 、LiZr 2 (PO 4 ) 3 、LiOH、LiF、Li 4 ZrF 8 、Li 3 Zr 4 F 19 、Li 3 TiF 6 、LiAlF 4 、LiYF 4 、LiNbF 6 、ZrO 2 、Al 2 O 3 、TiO 2 、ZrF 4 、AlF 3 、TiF 4 、YF 3 、NbF 5 、or a combination thereof The composition according to claim 35, having the following characteristics.

39. A composition comprising cathode active material particles and a coating in contact with the cathode active material particles, substantially as shown in Figure 10, Figure 11, Figure 12, or Figure 13.

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