Methods for composition and methods for making NANO-coatings

Abstract

Described herein are ionically conductive nano-layers that comprises a compound of the formula AxMy(XmOn)z. In this formula, 'A' represents one or a combination of Li+, Na+, K+, or Cs+, or a combination thereof; 'M' represents one or a combination of divalent cations (Mg2+, Ca2+, Ba2+, Zn2+, Co2+, Ni2+, and Mn2+), trivalent cations (Al3+, B3+, Y3+, and V3+), rare earth metal ions, and tetravalent cations (Zr4+ and Ti4+); 'X' includes P5+, Si4+, and B3+; 'x' is an integer from 1 to 3; 'y' is an integer from 0 to 2, and 'z' is an integer from 1 to 3; 'm' is an integer from 1 to 2, and 'n' is an integer from 3 to 7. This ionic conductive nano-layer or this nano-layer integrated with electronic conductive carbon nano-layer is positioned over a cathode material or a cathode material precursor.

Description

Attorney Docket No.67864-701.601 METHODS FOR COMPOSITION AND METHODS FOR MAKING NANO-COATINGS CROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 571,987 filed on March 29, 2024, which is incorporated by reference herein in its entirety. BACKGROUND

[0002] The disclosed technology relates generally to battery systems, devices, and methods. More particularly, the disclosed technology relates to compositions and processes for forming ionically conductive nano-coatings on polyanion cathode materials and cathode precursors, thereby enhancing electronic and ionic conductivity, improving rate performance, low‐ temperature capacity, fast‐charging capability, and overall safety of electrochemical energy storage devices.

[0003] Traditional polyanion cathode materials such as lithium iron phosphate (LFP) have typically exhibited slow kinetics due to limited electron and ion transport, presenting a considerable obstacle. Previous attempts at resolution have focused on increasing electronic conductivity using nano-carbon or metal coatings. However, these methods have not substantially improved ionic conductivity. SUMMARY

[0004] Recognized herein is a need for compositions and methods that may improve the performance, stability, and safety of polyanion-based battery cathodes subject to slow kinetics and limited ion or electron transport. The present disclosure provides compositions and methods for forming ionically conductive nano-layers on such cathodes. In some cases, doping strategies, alkali ion exchange, or protective surface treatments may be employed to enhance both electronic and ionic conductivity. These compositions and methods may address inefficiencies in existing processes by reducing side reactions, mitigating corrosion, and increasing low- temperature performance, thereby extending the operating lifespan of energy storage devices through improved chemical stability and more robust cathode interfaces.

[0005] In an aspect, the present disclosure provides nano-layers, comprising an ionically conductive material comprising a compound of formula AxMy(XmOn)z, wherein: A is selected from the group consisting of Li+, Na+, K+, or Cs+, and a combination thereof; M is selected from the group consisting of divalent cations of Mg2+, Ca2+, Ba2+, Zn2+, Co2+, Ni2+, and Mn2+, trivalent cations of Al3+, B3+, Y3+, and V3+, rare earth metal ions, and tetravalent cations of Zr4+and Ti4+, and a combination thereof; X comprises P5+, Si4+, or B3+; x is an integer of 1 to 4; y isAttorney Docket No.67864-701.601 an integer of 0 to 2; z is an integer of 1 to 3, m is an integer of 1 to 2; and n is an integer of 2 to 7, wherein the nano-layer is on top of a cathode material or a cathode material precursor.

[0006] In some embodiments, x is 3, y is 0, z is 1, m = 1, n = 4, and X = P⁵⁺. In some embodiments, the compound is selected from Li3PO4, Na₃PO₄, K₃PO₄, Cs3PO4, LiaNa(3-a)PO4, or CsaNa(3-a)PO4, where a is a real number ranging from 0 to 3. In some embodiments, x is 3, y is 0, z is 1, m = 1, n = 4, and X = P⁵⁺.

[0007] In some embodiments, the compound is selected from Li3PO4, Na3PO4, K3PO4, Cs3PO4, Li^Na₍3-a₎PO₄, or Cs^Na₍3-a₎PO₄, where a is a real number ranging from 0 to 3.

[0008] In some embodiments, x is 4, y is 0, z is 1, m = 2, n = 7, and X = P⁵⁺.

[0009] In some embodiments, the compound is chosen from Li4P2O7, Na4P2O7, K4P2O7, Cs4P2O7, LiaNa(4-a)P2O7, or KaNa₍4-a)P2O7, where a is a real number ranging from 0 to 4.

[0010] In some embodiments, x is 2, y is 0, z is 1, m = 1, n = 3, and X = Si4⁺.

[0011] In some embodiments, the compound is selected from Li2SiO3, Na2SiO3, K2SiO3, or Cs2SiO3. In some embodiments, x is 4, y is 0, z is 1, m = 2, n = 4, and X = Si4⁺.

[0012] In some embodiments, the compound is chosen from Li4SiO4, Na4SiO4, K4SiO4, or Cs4SiO4.

[0013] In some embodiments, x is 1, y is 0, z is 1, m = 1, n = 2, and X = B3⁺.

[0014] In some embodiments, the compound is selected from LiBO2, NaBO2, KBO2, or CsBO2.

[0015] In some embodiments, x is 3, y is 0, z is 1, m = 1, n = 3, and X = B3⁺. In some embodiments, the compound is chosen from Li3BO3, Na3BO3, K3BO3, or Cs3BO3.

[0016] In some embodiments, x is 1, y is 1, z is 1, and X = P5⁺. In some embodiments, the compound is selected from LiMgPO4, LiZnPO4, LiCaPO4, NaMgPO4, NaZnPO4, KMgPO4, or CsMgPO4.

[0017] In some embodiments, x is 2, y is 1, z is 1, m = 1, n = 4, and X = Si4⁺. In some embodiments, the compound is chosen from Li2MgSiO4, Li2ZnSiO4, Li2CaSiO4, Na2MgSiO4, or Na2ZnSiO4.

[0018] In some embodiments, x is 2, y is 1, z is 2, m = 1, n = 4, and X = P⁵⁺. In some embodiments, the compound is selected from Li2Ti(PO4)2, Li2Zr(PO4)2, Na₂Zr(PO4)2, K₂Zr(PO4)2, or Cs2Zr(PO4)2. In some embodiments, x is 3, y is 2, z is 3, and X = P⁵⁺.

[0019] In some embodiments, the compound is chosen from Li3Al2(PO4)3, Li3V2(PO4)3, Li3Y2(PO4)3, Li3La2(PO4)3, Na3Al2(PO4)3, or Na3Y2(PO4)3.

[0020] In some embodiments, x is 1, y is 2, z is 3, m = 1, n = 4, and X = P⁵⁺.

[0021] In some embodiments, the compound is selected from LiZr2(PO4)3or LiTi2(PO4)3.

[0022] In some embodiments, the cathode material comprises a phosphate-based cathode material.Attorney Docket No.67864-701.601

[0023] In some embodiments, the phosphate-based cathode material comprises LiFePO₄ (LFP), LiMnx1Fe(1-x1)PO₄, LiMnPO₄, LiCoPO₄, LiNiPO₄, or Li₃V₂(PO₄)₃, where x1 is a real number ranging from 0 to 1.

[0024] In some embodiments, the cathode material comprises a silicate-based cathode material, and in some embodiments, the silicate-based cathode material comprises Li2FeSiO4or Li2MnSiO4.

[0025] In some embodiments, the cathode material comprises a cathode material precursor, and in some embodiments, the cathode material precursor comprises a phosphate-based cathode material precursor.

[0026] In some embodiments, the phosphate-based cathode material precursor comprises FePO4, MnPO4, Fex2Mny2PO4, or CoPO4, where x2and y2are real numbers between 0 and 1 such that x2+ y2equals 1.

[0027] In some embodiments, the cathode material precursor comprises a silicate-based cathode material precursor, wherein the silicate-based cathode material precursor comprises FeSiO3or MnSiO3.

[0028] In some embodiments, the cathode material precursor comprises a mixed metal carbonate, and in some embodiments, the mixed metal carbonate comprises Nix3Coy3Mnz3CO3, where x₃, y₃, and z₃ are real numbers between 0 and 1 with x3+ y3+ z3equaling 1.

[0029] In some embodiments, the mixed metal carbonate comprises a mixed metal hydroxide.

[0030] In some embodiments, the mixed metal hydroxide comprises Nix4Coy4Niz4(OH)2, where x₄, y₄, and z₄ are real numbers between 0 and 1 such that x₄ + y₄ + z₄ equals 1.

[0031] In some embodiments, the mixed metal hydroxide comprises Nix4Coy4Mnz4(OH)2, where x₄, y₄, and z₄ are real numbers between 0 and 1 such that x₄ + y₄ + z₄ equals 1.

[0032] In some embodiments, the nano-layer further comprises one or more sodium cathode precursors.

[0033] In some embodiments, the cathode material comprises a layered oxide cathode material, and in some embodiments, the layered oxide cathode material comprises LiCoO₂-based, Nickel Manganese Cobalt-based (e.g., NMC-based), Nickel Cobalt Aluminum-based (e.g., NCA- based), or Li-rich manganese oxide-based cathode materials.

[0034] In some embodiments, the cathode material comprises an ultra-high voltage cathode material such as LiCoPO4, LiNi0.5Mn1.5O4, Li-rich manganese-based cathode materials, a 5.0 V cathode material, or a combination thereof, and in some embodiments, the ultra-high voltage cathode material comprises LiNi0.5Mn1.5O4.Attorney Docket No.67864-701.601

[0035] In some embodiments, the ultra-high voltage cathode material further comprises one or more sodium cathode materials, and in some embodiments, the cathode material precursor is used to form a cathode material.

[0036] In another aspect, provided herein, are methods for surface coating of polyanion cathode active materials with a nano-layer, enhancing both ionic and electronic transport properties, the method comprising: (a) providing a cathode material described herein; and (b) applying a nano- layer described herein to the cathode material of (a). BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which:

[0038] FIG.1 shows a non-limiting, exemplary depiction of a charge profile for a rechargeable lithium iron phosphate (LFP) cell, in accordance with some embodiments;

[0039] FIG.2 shows a non-limiting, exemplary depiction of a nano-coating applied to a generally spherical battery substrate, in accordance with some embodiments; and

[0040] FIG.3 shows a non-limiting, exemplary depiction of rate performance profile of an LFP (lithium iron phosphate) cell under various charging conditions, in accordance with some embodiments. DETAILED DESCRIPTION Terms and Definitions

[0041] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0042] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Any reference to "or" herein is intended to encompass "and / or" unless otherwise stated.

[0043] As used herein, the term "about" in some cases refers to an amount that is approximately the stated amount, in some cases near the stated amount by 10%, 5%, or 1%, including increments therein, and in some cases, in reference to a percentage, refers to an amount that is greater or less the stated percentage by 10%, 5%, or 1%, including increments therein.

[0044] As used herein, the phrases "at least one," "one or more," and "and / or" are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B and C," "at least one of A, B, or C," "one or more of A, B, andAttorney Docket No.67864-701.601 C", "one or more of A, B, or C" and "A, B, and / or C" means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

[0045] Reference throughout this specification to "some embodiments," "further embodiments," or "a particular embodiment," means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in some embodiments," or "in further embodiments," or "in a particular embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0046] The term "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not.

[0047] As used herein, the recitation of a numerical range for a variable is intended to convey that the variable is equal to any of the values within that range. Thus, for a variable which is inherently discrete, the variable is equal to any integer value within the numerical range, including the end-points of the range. Similarly, for a variable which is inherently continuous, the variable is equal to any real value within the numerical range, including the end-points of the range. As an example, and without limitation, a variable which is described as having values between 0 and 2 takes the values 0, 1 or 2 if the variable is inherently discrete, and takes the values 0.0, 0.1, 0.01, 0.001, or any other real values 0 and 2 if the variable is inherently continuous.

[0048] As used herein, unless specifically indicated otherwise, the word "or" is used in the inclusive sense of "and / or" and not the exclusive sense of "either / or."

[0049] As used herein, "A" generally refers to Ampere, the standard unit measuring the rate of flow of electric current. In some cases, it may be used, for example, to quantify charging currents.

[0050] As used herein, "Ah" generally refers to Ampere-hour, a unit of electric charge commonly used to express the nominal capacity of a battery cell or pack. It may represent the amount of charge delivered by a current of one Ampere flowing for one hour.

[0051] As used herein, "battery" or "batteries" generally denotes an electrochemical device capable of storing energy and delivering it as electrical power, facilitated by the chemical reaction occurring between the anode (negative electrode), cathode (positive electrode), and electrolyte (ionic conductor). This definition may encompass a broad range of batteries, including but not limited to those used in electric vehicle (EV) technology. In an EV context, a "battery" may often signify a "battery pack," composed of multiple individual cells engineeredAttorney Docket No.67864-701.601 to meet power and energy demands. Common battery types in EVs may include lithium-ion, sodium-ion, nickel-metal hydride, and solid-state batteries, each potentially having unique energy density, power delivery, charging speed, safety, lifespan, and environmental characteristics. The term "battery," as used here, may be representative and may cover other forms and applications not explicitly defined.

[0052] As used herein, "C-rate" refers to the rate at which a battery is charged or discharged relative to its nominal capacity. For instance, a rate of 1C may mean the battery is fully charged or discharged in one hour, while higher rates like 5C may indicate faster charging / discharging (e.g., in 12 minutes).

[0053] As used herein, "°C" generally refers to degrees Celsius, the standard unit for measuring temperature. It may be used to specify operating and testing conditions for batteries, such as charging temperatures or low-temperature performance evaluation.

[0054] As used herein, "g" generally refers to gram, a standard unit of mass. It may frequently be used to quantify materials in experimental procedures (e.g., grams of precursor material) or in specific capacity measurements (mAh / g).

[0055] As used herein, "km" generally refers to kilometer, a standard unit of distance equal to 1000 meters. It may be used in the context of vehicle range achievable with the battery technology described.

[0056] As used herein, "LT-LFP" generally refers to Low-temperature Lithium Iron Phosphate. It may be a form of Lithium Iron Phosphate (LiFePO4, abbreviated as LFP), which may often be used in lithium-ion batteries due to potentially beneficial properties such as high thermal stability and long cycle life, and may be capable of operating at frigid temperatures. For example, the frigid temperature may comprise winter temperatures as frigid as -20°C or lower.

[0057] As used herein, "M" generally refers to Molar, a unit of concentration representing moles of solute per liter of solution (mol / L). It may be used to specify electrolyte concentrations, such as 1 M LiPF6.

[0058] As used herein, "mAh / g" generally refers to milliampere-hour per gram, a unit representing specific capacity. It may quantify the amount of electrical charge a battery material can store per unit of its mass, and is commonly used to evaluate cathode material performance.

[0059] As used herein, "mL" generally refers to milliliter, a standard unit of volume equal to one-thousandth of a liter. It may be used to specify volumes of liquids, such as solvents or solutions, in experimental procedures.

[0060] As used herein, the phrases "nano-layer" or "nano-coating" generally refer to an ultra- thin coating, typically with a thickness in the nanometer scale (e.g., 1 to 100 nm), that may be applied to the surface of a material or object to modify or enhance its physical, chemical, and / orAttorney Docket No.67864-701.601 electrical properties. It may comprise a variety of substances, such as metals, alloys, ceramics, polymers, composite materials or a combination thereof, including embodiments where it comprises a solid-state electrolyte and conductive carbon. This nano-layer may be used in battery technology to enhance the performance of components like the anode, cathode, or separator, potentially delivering benefits such as increased ionic conductivity, improved electron transport, higher energy density, superior low- and high-temperature performance, faster charging capabilities, and prolonged battery life. Application techniques for the nano-layer may include methods like chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), dip-coating, spin-coating, and spraying. This definition may be representative and may include other forms and applications not explicitly stated.

[0061] As used herein, "nm" generally refers to nanometer, a unit of length equal to one billionth of a meter (10⁻⁹ m). It may be used to describe the thickness scale of the nano-coatings discussed.

[0062] As used herein, "rpm" generally refers to revolutions per minute, a unit measuring rotational speed. It may be used to specify conditions during material processing steps like ball milling.

[0063] As used herein, "V" generally refers to Volt, the standard unit of electric potential difference or voltage. It may be used to describe battery cell voltage during charging / discharging or the operating voltage range of cathode materials.

[0064] As used herein, "Wh / kg" generally refers to Watt-hour per kilogram, a unit of specific energy. It may measure the amount of energy stored in a battery per unit of its mass and is a key metric for energy density.

[0065] As used herein, "wt%" generally refers to weight percent, a unit expressing concentration based on mass. It may indicate the mass of a component relative to the total mass of the mixture, multiplied by 100, and may be used for specifying coating content or composite material composition. Overview

[0066] Recognized herein is a need for compositions and methods that may improve the performance, stability, and safety of polyanion-based battery cathodes, including those with limited ion or electron transport. The present disclosure provides compositions and methods that may enhance energy storage capabilities in such cathodes. In some embodiments, these compositions and methods may bolster electronic conduction and mitigate kinetic limitations. In some instances, they may reduce side reactions and extend operational life. For example, they may facilitate doping, alkali ion exchange, and surface protection to improve the overall safety and functionality of electrochemical devices.Attorney Docket No.67864-701.601

[0067] In some embodiments, the compositions and methods described herein may include one or more nano-coating layers configured to enhance both electronic and ionic conductivity. In some cases, a solid electrolyte layer may be combined with conductive materials to address surface defects. In some instances, approaches such as doping strategies, alkali ion exchange, or other modifications may be used to improve overall performance and stability and to mitigate undesired side reactions. For example, chemically stable coatings may bolster safety characteristics in polyanion cathodes. In further examples, applying solid-electrolyte-based nano-layers may extend the functional lifespan of energy storage cells.

[0068] In some embodiments, the present disclosure provides compositions and methods for making and applying ionically conductive nano-layers. In some cases, the ionically conductive nano-layers described herein comprise a compound of the formula A^M^(X^O^)z. In some instances, "A" may be Li⁺, Na⁺, K⁺, Cs⁺, or a combination thereof. In some instances, "M" may be selected from divalent cations (e.g., Mg²⁺, Ca²⁺, Ba²⁺, Zn²⁺, Co²⁺, Ni²⁺, Mn²⁺), trivalent cations (e.g., Al³⁺, B³⁺, Y³⁺, V³⁺), rare earth metal ions, or tetravalent cations (e.g., Zr⁴⁺, Ti⁴⁺),individually or in any combination. In some instances, "X" may include P⁵⁺, Si⁴⁺, or B³⁺, while x,y, z, m, and n may each vary over ranges allowing different formulations of the nano-layer. In some instances, the nano-layers described herein may be positioned over a cathode material or a cathode material precursor to provide targeted improvements in battery performance. Nano-Coating

[0069] The present disclosure provides compositions and methods for forming ionically conductive nano-coatings on one or more battery surfaces to enhance battery performance. In some embodiments, the electronic conductivity is increased when compared to batteries lacking the nano-coating described herein. In some cases, the ionic conductivity is improved when compared to batteries lacking the nano-coating described herein. In some instances, the low- temperature capacity is enhanced to deliver higher energy output at temperatures as low as - 20°C when compared to batteries lacking the nano-coating described herein. For example, the battery lifespan may be extended through improved chemical stability when compared to batteries lacking the nano-coating described herein. As an example, the safety characteristics may be improved by reducing thermal runaway risks when compared to batteries lacking the nano-coating described herein.

[0070] In some embodiments, the ionically conductive nano-layer described herein comprises a compound described herein to enhance both electron and ion transport. In some cases, the doping strategies and alkali ion exchange techniques improve structural integrity and performance of cathode materials. In some instances, the surface protection mechanisms mitigate corrosion and unwanted side reactions at the cathode-electrolyte interface. For example,Attorney Docket No.67864-701.601 the solid-electrolyte-based nano-layers may increase low-temperature performance of batteries from about 60% to about 80% capacity at temperatures as low as -20°C. As an example, the fast- charging capabilities may allow batteries to charge to about 80% capacity within about 10 minutes.

[0071] In some embodiments, the nano-coating facilitates a doping effect where ions from the coating material are introduced as substitutes for ions in the active cathode material. In some cases, this doping process creates beneficial defects at the interface between the coating and the cathode core, improving electrical conductivity. In some instances, when a coating (e.g., LiZr₂(PO₄)₃) is applied to LFP cathodes, zirconium ions may partially substitute for iron ions in the cathode lattice. For example, the doping effect may enhance electron mobility through the modified crystal structure. As an example, the controlled introduction of dopant ions may create additional conduction pathways that were not present in the unmodified cathode material.

[0072] In some embodiments, the nano-coating provides an alkali ion exchange mechanism when different alkali ions are present in the coating versus the cathode material. In some cases, using a coating with sodium ions (e.g., Na3PO4) on a lithium-based cathode (e.g., LFP) creates a concentration gradient that facilitates significant ion transport. In some instances, this exchange process enhances overall ionic conductivity at the interface. For example, the alkali ion exchange may improve rate capability and fast-charging performance when compared to uncoated cathodes. As an example, the mixed alkali ion environment may reduce energy barriers for ion migration during battery operation.

[0073] In some embodiments, a nano-coating layer is applied to the cathode surface to enhance ion transport. In some cases, a conductive additive is integrated into the nano-coating to support electron transfer. In some instances, a surface treatment procedure is performed to prepare the cathode interface prior to coating. For example, the doping process may insert specific ions to stabilize the lattice. As an example, alkali ion exchange may modify the cathode composition to improve structural integrity.

[0074] In some embodiments, the nano coatings are applied to the cathode in conjunction with conductive carbon. In some cases, the nano coatings provided herein effectively boost both electronic and ionic conductivity. In some cases, the nano-coatings provided herein are used in combination with strategies such as alkali ion exchange, doping, and prevention of corrosion and side reactions, improving the performance, stability, longevity, and safety of LFP-based batteries.

[0075] In some embodiments, the nano-coating is applied to at least one solid-state electrolyte surface. In some cases, the nano-coating is applied to at least one conductive carbon surface. InAttorney Docket No.67864-701.601 some cases, the nano-coating is configured to decrease battery failure. For example, the nano- coating may be configured to reduce the risks of thermal runaway and other battery failures.

[0076] In some embodiments, a device comprising one or more surfaces having a nano-coating described herein may charge up to a capacity threshold at a charging rate within a charging time frame and at a temperature to provide travel over a range within a travel time frame.

[0077] In some cases, the capacity threshold comprises between about 120 mAh / g and about 200 mAh / g at the charging temperature. In some instances, the threshold comprises between about 130 mAh / g and about 190 mAh / g at the charging temperature. For example, the capacity threshold may comprise between about 140 mAh / g and about 180 mAh / g at the charging temperature. As an example, the capacity threshold may comprise between about 150 mAh / g and about 170 mAh / g at the charging temperature.

[0078] In some embodiments, the device maintains a capacity percentage at a charging temperature. In some cases, the capacity threshold comprises between about 60% and 80% at the charging temperature when compared to room temperature capacity. In some instances, the capacity retention is improved by at least 20% at the charging temperature when compared to devices lacking the nano-coating. For example, the device may maintain about 70% of its room temperature capacity at the charging temperature. As an example, the capacity retention may increase from about 45% to about 75% at the charging temperature when the nano-coating is applied.

[0079] In some embodiments, the charging rate comprises the rate at which the battery is charged relative to its nominal capacity (C‐rate). In some cases, this charging rate comprises between about 0.1C and about 8C. In some instances, the charging rate comprises between about 0.1C and about 5C. For example, the charging rate may comprise between about 2C and about 6C. As an example, the charging rate may comprise between about 1C and about 8C.

[0080] In some embodiments, the charging rate comprises between about 0.1C and about 5C, providing "superfast" charging (e.g., see FIG.3). In some cases, charging at about 5C allows the battery to reach 80% capacity in about 10 minutes compared to similar batteries lacking the nanocoating. In some instances, a more conservative range of about 0.1C to 2C balances speed with longevity. For example, a 2C to 5C range may achieve about 66% capacity in roughly 8 minutes. As an example, a 5C rate may yield full capacity in about 20 minutes, demonstrating how the nanocoating supports faster charge times.

[0081] In some embodiments, the temperature comprises the ambient or cell temperature at which the battery is maintained during charging or discharging. In some cases, this temperature comprises between about –30 °C and about 60 °C. In some instances, the temperature comprises between about –20 °C and about 50 °C. For example, the temperature may comprise betweenAttorney Docket No.67864-701.601 about 0 °C and about 40 °C. As an example, the temperature may comprise between about 15 °C and about 35 °C.

[0082] In some embodiments, the nano-coating operates across a temperature range from about - 20°C to about 50°C when compared to similar coatings lacking this thermal stability. In some cases, the improve ion conductivity occurs between 15°C and 40°C as measured by electrochemical impedance spectroscopy. In some instances, doping treatments or surface modifications further stabilize the cathode interface between 20°C and 30°C. For example, the narrower temperature band may provide balanced safety margins and high performance between 25°C and 35°C. As an example, the battery temperature may be maintained near 20°C to support stable capacity retention and extended cycle life.

[0083] In some embodiments, the range comprises the distance a device may travel using the stored energy of the charged battery. In some cases, this range comprises between about 0.1 km and about 1000 km. In some instances, the range comprises between about 100 km and about 700 km. For example, the range may comprise between about 200 km and about 600 km. As an example, the range may comprise between about 400 km and about 700 km.

[0084] In some embodiments, the nano-coating enhances performance so that at –20 °C, the vehicle may achieve between about 420 km and about 560 km of range. In some cases, this represents up to a 40% boost over similar batteries lacking the nanocoating. In some instances, moderate temperatures permit a general range of 50 km to 300 km for smaller vehicles or personal devices. For example, typical daily commutes of 120 km to 200 km may be supported without sacrificing performance. As an example, extended highway driving in the 150 km to 200 km band remains feasible with midrange battery capacities.

[0085] In some embodiments, the time frame comprises the duration in which the device travels or the time needed to achieve a certain battery charge level. In some cases, this time frame comprises between about 5 minutes and about 120 minutes. In some instances, the time frame comprises between about 10 minutes and about 90 minutes. For example, the time frame may comprise between about 20 minutes and about 60 minutes. As an example, the time frame may comprise between about 15 minutes and about 30 minutes.

[0086] FIG.1 shows a non-limiting example that charging at 5C allows the battery to reach 80% in about 10 minutes, corresponding to a short time frame. In some cases, a time frame of about 20 minutes to 60 minutes balances fast charging and battery longevity. In some instances, about 30 minutes to 45 minutes is sufficient for moderate C‐rates, delivering near‐full capacity without excessive stress. For example, a 15 minute to 30 minute window provides a quick top‐off for long‐distance drives. As an example, certain operating modes may allow a 5 minute rapid partial charge to extend immediate driving range.Attorney Docket No.67864-701.601

[0087] In some embodiments, the nano-coating beneficial increases the low-temperature performance of LFP batteries. In some cases, increasing the low-temperature performance leads to an elevation in battery capacity from about 60% to approximately 80% or more when the temperature drops to about -20°C. In some instances, the nano-coating enhancement translates to a vehicle range expansion from about 420 km to about 560 km or more in winter at temperatures as frigid as -20°C or lower. In some instances, the nano-coating enhancement translates to a vehicle range expansion up to about 560 km in winter at temperatures as frigid as -20°C or lower.

[0088] In some embodiments, the nano-coating is applied to a battery surface (e.g., a cathode). In some cases, applying the nano-coating to the battery surface configures the battery for superfast charging capabilities. In some instances, applying the nano-coating to the battery surface configures the battery to charge to about 80% or more capacity within about 10 minutes. In some instances, this corresponds to a vehicle range of about 466 km or greater. In some instances, this corresponds to a vehicle range of up to about 466 km.

[0089] In some embodiments, the nano-coating is configured to augment both an electronic and an ionic conductivity of a battery (e.g., improving their performance and operational efficiency). In some cases, the nano-coating is configured to augment both an electronic and an ionic conductivity of an LFP battery.

[0090] In some embodiments, the nano-coating is configured to improve a battery conductivity. In some cases, the nano-coating is configured to increase the energy density of a battery from 170 Wh / kg to 240 Wh / kg. In some cases, the nano-coating is configured to increase the energy density of a battery by at between about 0 Wh / kg to about 70 Wh / kg. In some cases, the nano- coating is configured to increase the energy density of a battery by at least about 70 Wh / kg.

[0091] In some cases, the nano-coating is configured to extend a device’s nominal range (e.g., an electric vehicle) considerably by up to about 40%, or greater (e.g., scaling up from 500 km to 700 km).

[0092] FIG.1 shows a non-limiting example of a charge profile 100 for a rechargeable lithium iron phosphate (LFP) cell having a nominal capacity of 1.2 ampere-hours (Ah), under two distinct charging protocols: a standard charge rate of 1C (approximately 1.2 amperes) and a fast charge rate of 5C (approximately 6 amperes). In this example, the horizontal axis 102 represents charge time in minutes, ranging from 0 to about 90 minutes. The left vertical axis 103 indicates charge capacity as a percentage of nominal capacity, from 0% to 120%, while the right vertical axis 104 shows charge current in amperes, from 0 A to 9 A.

[0093] As shown in this example, four curves illustrate the behavior of the cell during charging. A first curve 105, depicted as a solid line, shows the charge capacity profile at a 1C rate. In thisAttorney Docket No.67864-701.601 instance, the capacity increases gradually and reaches approximately 100% within about 70 minutes, consistent with a typical constant-current / constant-voltage (CC / CV) charging scheme.

[0094] A second curve 106, illustrated as a dashed line, corresponds to charging at a 5C rate. This example curve exhibits a steeper initial rise, reaching approximately 80% state-of-charge (SOC) in less than 15 minutes. The curve then flattens as the cell transitions from the constant- current to the constant-voltage phase, indicating a reduction in charge acceptance.

[0095] A third curve 107, shown as a solid trace separate from the capacity lines, represents the current profile during the 1C charging cycle. The current in this example remains relatively constant during the CC phase and begins to taper gradually as the cell nears full charge, signaling the onset of the CV phase.

[0096] A fourth curve 108, depicted as a dotted line, represents the current profile for the 5C charging cycle. The curve initially holds at a constant 6 A before dropping off more abruptly as the cell transitions into the CV phase, which occurs earlier in the charging process compared to the 1C case.

[0097] This example charge profile highlights the operational trade-offs between fast and standard charging. The 5C charge rate (curves 106 and 108) delivers rapid initial charging but results in a sharper current decline, which may introduce higher thermal or electrochemical stress. Conversely, the 1C charge rate (curves 105 and 107) provides a more gradual and controlled charge cycle, potentially supporting improved cell longevity and thermal stability. FIG.1 thus provides a comparative illustration of charging dynamics for an LFP cell under different current protocols, which may inform the configuration and calibration of battery management systems (BMS) and charging strategies in various application environments.

[0098] FIG.2 shows a non-limiting, exemplary depiction of a nano-coating 201 applied to a generally spherical battery substrate 200, in accordance with embodiments. In this illustrated example, the dome-shaped region 201 represents the ionically conductive layer formed over the substrate’s surface 202, highlighting only partial coverage of the sphere. It should be understood, however, that other embodiments may feature full or varied extents of coverage by the nano-coating as described herein.

[0099] FIG.3 shows a non-limiting, exemplary depiction of rate performance profile 300 of an LFP (lithium iron phosphate) cell under various charging conditions. In this example, the graph depicts voltage versus specific capacity behavior for the LFP cell when charged at different C- rates, providing insight into performance characteristics under varying charge rates.

[0100] The x-axis 307 represents the specific capacity (in mAh / g), which in this example ranges from 0 to approximately 180 mAh / g. The y-axis 308 represents the voltage of the cell (V vs. Li / Li⁺), ranging in this instance from approximately 2.0 V to 4.5 V.Attorney Docket No.67864-701.601

[0101] Multiple charge profiles are shown, each corresponding to a different constant current (C-rate) charging condition. For example, curve 301 shows charging at a rate of 0.1C, achieving a capacity of approximately 161 mAh / g. Curve 302 represents a 0.2C rate, with a capacity of about 156 mAh / g. Curves 303 and 304 correspond to 1C and 5C charging rates, respectively, illustrating lower delivered capacities of approximately 146 mAh / g and 127 mAh / g. In this particular example, a mid-range rate of 2C 305 results in a delivered capacity of around 142 mAh / g.

[0102] As shown in this example, increasing the charge rate generally leads to increased polarization and reduced capacity, evidenced by the lowering and flattening of the voltage plateau as the C-rate increases. This trend is observable in the stacked curves and is characteristic of kinetic limitations in lithium-ion chemistry.

[0103] This example rate profile can be useful for evaluating trade-offs between charge time and delivered energy, such as in applications where rapid charging is desired but must be balanced against cell degradation or thermal constraints. For instance, the data may inform configuration decisions in electric vehicle battery packs, consumer electronics, or grid storage modules.

[0104] While FIG.3 depicts one illustrative embodiment, it should be understood that other variations in cell chemistry, form factor, or temperature conditions may yield different performance curves. Compositions

[0105] The present disclosure provides, in some embodiments, a nano-layer that includes an ionically conductive material. In some embodiments, the nano-coating layer comprises a compound (e.g., an ionic conductor) of a general formula AxMy(XmOn)z. In these formulas, "A" refers to an alkali metal, "M" refers to a divalent cation, trivalent cations, rare earth metal ions, tetravalent cations and combinations thereof, "X" refers to P5+, Si4+, and B3+, or a combination thereof, "m" is an integer of 1 and 2, "n" is an integer of 2 to 7, "x" is an integer of 1 to 4, "y" is an integer of 0 to 2, "z" is an integer of 1 to 3.

[0106] In some embodiments, "A" comprises an alkali metal. In some cases, "A" comprises an alkali metal ion. In some cases, the alkali metal may comprise Lithium (Li+), Sodium (Na+), Potassium (K+), Rubidium (Rb+), or Cesium (Cs+), or a combination thereof.

[0107] In some cases, "A" comprises Li+. In some cases, "A" comprises Na+. In some cases, "A" comprises K+. In some cases, "A" comprises Cs+. In some cases, "A" comprises Li+, Na+, K+, Cs+, or a combination thereof. In some cases, "A" comprises two or more alkali metals selected from the group consisting of Li+, Na+, K+, and Cs+. In some cases, "A" comprises three or more alkali metals selected from the group consisting of Li+, Na+, K+, and Cs+.Attorney Docket No.67864-701.601

[0108] In some embodiments, "M" comprises a divalent cation. In some cases, the divalent cation comprises Mg2+, Ca2+, Ba2+, Zn2+, Co2+, Ni2+, or Mn2+, or a combination thereof.

[0109] In some embodiments, "M" comprises a trivalent cation. In some cases, the trivalent cation comprises Al3+, B3+, Y3+, or V3+, or a combination thereof.

[0110] In some embodiments, "M" comprises a rare earth metal ion. A rare earth metal ion may comprise La3+, Ce3+, or Gd3+, or a combination thereof.

[0111] In some embodiments, "M" comprises a tetravalent cation. In some cases, the tetravalent cation may comprise Zr4+, Ti4+or a combination thereof.

[0112] In some embodiments, "X" comprises a nonmetal element. In some cases, "X" is phosphorous (P5+). In some cases, "X" is silicon (Si4+). In some cases, "X" is boron (B3+). In some cases, "X" is a combination of at least two of P5+, Si4+, and B3+. In some cases, "X" is a combination of P5+, Si4+, and B3+.

[0113] In some embodiments, "x" is an integer from 1 to 4. In some cases, "x" is about 1.5, 2, 2.5, 3, 3.5, or 4. In some cases, "x" is a number from about 1.2 to about 3.7. In some cases, "x" is a number from about 1.5 to about 3.5. In some cases, "x" is a number from about 2 to about 3. In some cases, "x" is a number from about 2.3 to about 3.6. In some cases, "x" is about 3.8.

[0114] In some embodiments, "y" is an integer from 0 to 2. In some embodiments, "y" is a number from 0 to 2. In some cases, "y" is about 0.5, 1, 1.2, 1.4, 1.6, 1.8, or 2. In some cases, "y" is a number from about 0.7 to about 1.8. In some cases, "y" is a number from about 1 to about 1.9. In some cases, "y" is a number from about 1.2 to about 1.6. In some cases, "y" is a number from about 1.4 to about 1.7. In some cases, "y" is about 1.5.

[0115] In some embodiments, both "x" and "y" are not 0. In some cases, "x" is 0 and "y" is not 0. In some cases, "y" is 0 and "x" is not 0. In some cases, "x" is not 0 and "y" is not 0.

[0116] In some embodiments, "m" is an integer from 1 to 2. In some embodiments, "m" is a number from 1 to 2. In some cases, "m" is about 1.5. In some cases, "m" is a number from about 1.2 to about 1.8. In some cases, "m" is a number from about 1.3 to about 1.7. In some cases, "m" is a number from about 1.4 to about 1.6. In some cases, "m" is a number from about 1.45 to about 1.55. In some cases, "m" is about 1 or 2.

[0117] In some embodiments, "n" is a real number from 2 to 7.

[0118] In some embodiments, "z" is an integer from 1 to 3. In some embodiments, "z" is a number from 1 to 3. In some cases, "z" is about 1.5, 2, 2.5, or 3. In some cases, "z" is a number from about 1.2 to about 2.8. In some cases, "z" is a number from about 1.5 to about 2.5. In some cases, "z" is a number from about 2 to about 3. In some cases, "z" is a number from about 2.3 to about 2.7. In some cases, "z" is about 2.9.Attorney Docket No.67864-701.601

[0119] In some instances, X is P5+. For example, wherein x=3, m=1, n=4, and X=P5+, the compound may comprise A3PO4. In further examples, A3PO4may comprise Li3PO4, Na3PO4, K3PO4, Cs3PO4, LiaNa(3-a)PO4, CsaNa(3-a)PO4, wherein "a" is 2.

[0120] In further examples, wherein x=4, m=2, n=7, and X=P5+, the compound may comprise A4P2O7. In even further examples, A4P2O7may comprise Li4P2O7, Na4P2O7, K4P2O7, or Cs4P2O7.

[0121] In some instances, X is Si4+. For example, wherein x=2, m=1, n=3, and X=Si4+, the compound may comprise A2SiO3. In further examples, A2SiO3may comprise Li2SiO3, Na2SiO3, K2SiO3, or Cs2SiO3.

[0122] In further examples, wherein x=4, m=2, n=4, and X=Si4+, the compound may comprise A4SiO4. In even further examples, A4SiO4may comprise Li4SiO4, Na4SiO4, K4SiO4, or Cs4SiO4.

[0123] In some instances, X is B3+. For example, wherein x=1, m=1, n=2, and X=B3+, the compound may comprise ABO2.

[0124] In further examples, ABO2may comprise LiBO2, NaBO2, KBO2,or CsBO2.

[0125] In further examples, where x=3, m=1, n=3, and X=B3+, the compound may comprise A3BO3. In further examples A3BO3may comprise Li3BO3, Na3BO3, K3BO3, or Cs3BO3.

[0126] In some instances, X is P5+. For example, wherein x=1, m=1, n=4, and X=P5+, the compound may comprise AMPO4. In further examples, AMPO4may comprise LiMgPO4, LiZnPO4, LiCaPO4, NaMgPO4, NaZnPO4, KMgPO4, CsMgPO4, or other variations where "A" is an alkali metal and "M" represents a divalent cation.

[0127] In some instances, X is Si4+. For example, wherein x=2, m=1, n=4, and X=Si4+, the compound may comprise A2MSiO4. In further examples, A2MSiO4may comprise Li2MgSiO4, Li2ZnSiO4, Li2CaSiO4, Na2MgSiO4, Na2ZnSiO4, or other variations where "A" is an alkali metal and "M" represents a divalent cation.

[0128] In some instances, X is P5+. For example, wherein x=2, m=1, n=4, and X=P5+, the compound may comprise A2M(PO4)2. In further examples, A2M(PO4)2may comprise Li2Ti(PO4)2, Li2Zr(PO4)2, Na2Zr(PO4)2, K2Zr(PO4)2, Cs2Zr(PO4)2, or other variations where "A" is an alkali metal and "M" represents a tetravalent cation.

[0129] In some instances, X is P5+. For example, wherein x=3, z=3, and X=P5+, the compound may comprise A3M2(PO4)3. In further examples, A3M2(PO4)3 may comprise Li3Al2(PO4)3, Li3V2(PO4)3, Li3Y2(PO4)3, Li3La2(PO4)3, Na3Al2(PO4)3, Na3Y2(PO4)3, or other variations where "A" is an alkali metal and "M" represents a trivalent cation.

[0130] In some instances, X is P5+. For example, wherein x=1, z=3, and X=P5+, the compound may comprise AM2(PO4)3. In further examples, AM2(PO4)3may comprise LiZr2(PO4)3,Attorney Docket No.67864-701.601 LiTi2(PO4)3, or other variations where "A" is an alkali metal and "M" represents a tetravalent cation.

[0131] The nano-layer, in various embodiments, comprises an ionically conductive layer configured to be integrated into a parts of a battery (e.g., each application bringing about unique enhancements in the device’s performance).

[0132] In other embodiments, the nano-layer is configured to be part of an anode of a battery, may improve the battery’s charge and discharge rates through improved ionic conductivity at the anode. In certain cases, the nano-layer may be positioned on top of the anode material. In some instances, the positioning the nano-layer on top of the anode material may serve a similar protective and performance-enhancing function as in the positioning the nano-layer on top of the cathode material.

[0133] Furthermore, in some embodiments, the nano-coating is configured to be applied between the anode and cathode. In some cases, applying the nano-coating between the anode and cathode creates a supplementary ionic pathway to facilitate a smooth transfer of ions (e.g., during battery operation).

[0134] In some cases, the nano-coating is applied to a separator. In some instances, applying the nano-coating to the separator reduces the risk of internal short circuits while improving ionic conductivity.

[0135] In some cases, the nano-layer is configured to form part of a solid electrolyte layer. In some instances, the nano-layer forming part of the solid electrolyte layer is configured to optimize an ionic conductivity of the solid electrolyte layer. For example, the nano-layer forming part of the solid electrolyte layer enhances ion transport characteristics and improves ionic mobility and overall battery performance. Cathodes

[0136] In some embodiments, the nano-layer is configured to be integrated into a cathode of a battery (e.g., may improving the exchange of ions at the cathode-electrolyte interface). In some cases, the nano-layer may be positioned on top of the cathode material (e.g., may protecting the cathode from degradation or optimizing its interaction with the electrolyte).

[0137] In some embodiments, the nano-layer is configured to be integrated with a cathode material.

[0138] In some cases, the cathode materials may comprise lithium polyanion materials. In some instances, the lithium polyanion material may comprise a phosphate-based cathode material, a silicate-based cathode material, a sodium-based cathode materials, a layered-based Nax5MO2, or a combination thereof.Attorney Docket No.67864-701.601

[0139] In some cases, "x5" is a real number ranging from 0 to 1. In some cases, "x5" is a number between 0 and 1. In some cases, "x5" is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some cases, "x5" is a number between about 0.2 and about 0.8. In some cases, "x5" is a number between about 0.3 and about 0.7. In some cases, "x5" is a number between about 0.4 and about 0.6. In some cases, "x5" is about 0.5.

[0140] In some embodiments, the cathode material may comprise a cathode material precursor. In some cases, the cathode material precursor comprises a polyanions mixed metal hydroxides, mixed metal carbonate, or a combination thereof.

[0141] In some embodiments, the cathode material comprises a phosphate-based cathode material.

[0142] In some embodiments, the phosphate-based cathode material comprises LiFePO4(LFP), LiMnx1Fe1-x1PO4, LiMnPO4, LiCoPO4, LiNiPO4, or Li3V2(PO4)3.

[0143] In some cases, "x1" is a number between 0 and 1. In some instances, "x1" is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, "x1" is a number between about 0.2 and about 0.8. In some instances, "x1" is a number between about 0.3 and about 0.7. In some cases, "x1" is a number between about 0.4 and about 0.6. In some instances, "x1" is about 0.1.

[0144] In some embodiments, the cathode material comprises a cathode material precursor.

[0145] In some embodiments, the cathode material precursor comprises a phosphate-based cathode material precursor.

[0146] In some embodiments, the phosphate-based cathode material precursor comprises FePO4, MnPO4, Fex2Mny2PO4, or CoPO4.

[0147] In some cases, "x2" is an integer from 0 to 1. In some cases, "x2" is a number from 0 to 1. In some instances, "x2" is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, "x2" is a number from about 0.2 to about 0.8. In some instances, "x2" is a number from about 0.3 to about 0.7. In some instances, x2 is a number from about 0.4 to about 0.6. In some instances, x2 is about 0.5.

[0148] In some cases, "y2" is an integer from 0 to 1. In some instances, "y2" is a number from 0 to 1. In some instances, "y2" is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, "y2" is a number from about 0.2 to about 0.8. In some instances, "y2" is a number from about 0.3 to about 0.7. In some instances, "y2" is a number from about 0.4 to about 0.6. In some instances, "y2" is about 0.5.

[0149] In some instances, x2+ y2is equal to 1.

[0150] In some cases, the phosphate-based cathode material precursor comprises FePO4, Mnx6Fe1-x6PO4, MnPO4, CoPO4, NiPO4, or V2(PO4)3.Attorney Docket No.67864-701.601

[0151] In some cases, "x6" is an integer from 0 to 1. In some cases, "x6" is a number from 0 to 1. In some instances, "x6" is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, "x6" is a number from about 0.2 to about 0.8. In some instances, "x6" is a number from about 0.3 to about 0.7. In some instances, "x6" is a number from about 0.4 to about 0.6. In some instances, "x6" is about 0.5.

[0152] In some embodiments, the cathode material comprises a silicate-based cathode material. In some cases, the silicate-based cathode material comprises Li2FeSiO4, or Li2MnSiO4.

[0153] In some embodiments, the cathode material precursor comprises a silicate-based cathode material precursor. In some cases, the silicate-based cathode material precursor comprises FeSiO3, MnSiO3, FeSiO4, or MnSiO4.

[0154] In some embodiments, the cathode material precursor comprises a mixed metal carbonate. In some cases, the mixed metal carbonate comprises Nix3Coy3Mnz3CO3.

[0155] In some instances, "x3" is an integer from 0 to 1. In some instances, x3 is a number from 0 to 1. In some instances, x3 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, x3 is a number from about 0.2 to about 0.8. In some instances, x3 is a number from about 0.3 to about 0.7. In some instances, x3 is a number from about 0.4 to about 0.6. In some instances, x3 is about 0.5.

[0156] In some instances, "y3" is an integer from 0 to 1. In some instances, y3 is a number from 0 to 1. In some instances, y3 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, y3 is a number from about 0.2 to about 0.8. In some instances, y3 is a number from about 0.3 to about 0.7. In some instances, y3 is a number from about 0.4 to about 0.6. In some instances, y3 is about 0.5.

[0157] In some instances, "z3" is an integer from 0 to 1. In some instances, z3 is a number from 0 to 1. In some instances, z3 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, z3 is a number from about 0.2 to about 0.8. In some instances, z3 is a number from about 0.3 to about 0.7. In some instances, z3 is a number from about 0.4 to about 0.6. In some instances, z3 is about 0.5.

[0158] In some instances, x3+y3+z3is equal to 1.

[0159] In some cases, the mixed metal carbonate comprises a mixed metal hydroxide. In some instances, the mixed metal hydroxide comprises Nix4Coy4Niz4(OH)2.

[0160] In some instances, "x4" is an integer from 0 to 1. In some instances, x4 is a number from 0 to 1. In some instances, x4 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, x4 is a number from about 0.2 to about 0.8. In some instances, x4 is a number from about 0.3 to about 0.7. In some instances, x4 is a number from about 0.4 to about 0.6. In some instances, x4 is about 0.5.Attorney Docket No.67864-701.601

[0161] In some instances, "y4" is an integer from 0 to 1. In some instances, y4 is a number from 0 to 1. In some instances, y4 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, y4 is a number from about 0.2 to about 0.8. In some instances, y4 is a number from about 0.3 to about 0.7. In some instances, y4 is a number from about 0.4 to about 0.6. In some instances, y4 is about 0.5.

[0162] In some instances, "z4" is an integer from 0 to 1. In some instances, z4 is a number from 0 to 1. In some instances, z4 is about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In some instances, z4 is a number from about 0.2 to about 0.8. In some instances, z4 is a number from about 0.3 to about 0.7. In some instances, z4 is a number from about 0.4 to about 0.6. In some instances, z4 is about 0.5.

[0163] In some instances, x4 +y4+ z4is equal to 1.

[0164] In some embodiments, the nano-layer comprises one or more sodium cathode precursors.

[0165] In some embodiments, the cathode material comprises a layered oxide cathode material. In some cases, the layered oxide cathode material comprises LiCoO2-based, Nickel Manganese Cobalt-based (e.g., NMC-based), Nickel Cobalt Aluminum-based (e.g., NCA-based), or Li-rich manganese oxide-based cathode materials.

[0166] In some embodiments, the cathode material comprises an ultra-high voltage cathode material. In some cases, the ultra-high voltage cathode material comprises LiNi0.5Mn1.5O4. In some instances, the ultra-high voltage cathode material further comprises one or more sodium cathode materials. In some instances, the ultra-high voltage cathode materials may comprise a cathode material configured for up to about 5.0 V. For example, ultra-high voltage cathode materials may include LiCoPO4and LiNi0.5Mn1,5O4and lithium-rich manganese-based compounds.

[0167] In some embodiments, the cathode material precursor is used to form a cathode material. Method

[0168] In some embodiments, a method for surface coating of polyanion cathode active materials with a nano-layer is provided. In some cases, the method comprises providing a cathode material and applying a nano-layer to the surface of the cathode material. In some instances, the method includes dissolving lithium, phosphate, and may comprise a carbon source into a solution, then introducing cathode particles to create a slurry. For example, the slurry is dried to form a nano-coating layer on the cathode particles, followed by high-temperature sintering under controlled atmospheric conditions. As an example, the sintering atmosphere may comprise N₂ or N₂ / 5%H₂ to prevent oxidation during thermal treatment. For example, the resulting nano-coating material may improve rate performance, cycling stability, low- temperature capacity, and fast charging capability of the cathode material.Attorney Docket No.67864-701.601

[0169] In some embodiments, the method comprises utilizing different precursors depending on the desired coating composition. In some cases, the method includes using metal acetates, metal oxalates, or metal nitrates as cation sources for the coating material. In some instances, the method involves specific carbon sources such as glucose, sucrose, or citric acid to form integrated carbon coatings. For example, the method may employ different solvents including deionized water or anhydrous ethanol depending on the solubility of precursors. As an example, the method may incorporate controlled atmosphere sintering using N₂ or N₂ / 5%H₂ environments to prevent oxidation during thermal treatment at temperatures ranging from approximately 450°C to approximately 720°C.

[0170] In some embodiments, the method comprises applying the nano-coating to various types of cathode materials or precursors. In some cases, the method includes coating commercial carbon-coated cathode materials to further enhance their properties. In some instances, the method involves coating cathode material precursors such as FePO₄, amorphous-LiFePO₄, or mixed metal hydroxides. For example, the method may incorporate different weight percentages of coating material ranging from about 1% to about 3% to optimize performance characteristics. As an example, the method may utilize specialized techniques for coating ultra-high voltage cathode materials such as LiNi0.5Mn1.5O4.

[0171] In some embodiments, the method preliminary ball milling of materials to achieve uniform particle size distribution. In some instances, the method involves precise temperature control during sintering, with temperatures ranging from about 450°C to about 720°C depending on coating composition. For example, the method may utilize different drying temperatures ranging from about 60°C to about 80°C prior to sintering to control precursor decomposition. As an example, the method may include varying sintering durations from approximately 3 hours to approximately 8 hours to improve crystallization of the coating layer.

[0172] In some embodiments, a nano‐layer comprises an ionically conductive material including a compound of formula A^M^(X^O^)z, wherein A is selected from the group consisting of Li⁺, Na⁺, K⁺, or Cs⁺, and combinations thereof. In some cases, M is selected from the group consisting of divalent cations of Mg²⁺, Ca²⁺, Ba²⁺, Zn²⁺, Co²⁺, Ni²⁺, and Mn²⁺; trivalent cations of Al³⁺, B³⁺, Y³⁺, and V³⁺; rare earth metal ions; and tetravalent cations of Zr⁴⁺ and Ti⁴⁺, andcombinations thereof. In some instances, X comprises P⁵⁺, Si⁴⁺, or B³⁺, wherein x is an integer of1 to 4, y is an integer of 0 to 2, z is an integer of 1 to 3, m is an integer of 1 to 2, and n is an integer of 2 to 7. For example, the nano‐layer may be positioned on top of a cathode material to enhance both ionic and electronic conductivity. As an example, the nano-layer may beneficial improve low‐temperature performance, with capacity retention increasing from about 60% to about 80% at temperatures of approximately -20°C.Attorney Docket No.67864-701.601

[0173] In some embodiments, the nano-layer is applied to a battery cathode to provide superfast charging capabilities. In some cases, this enhancement allows the battery to charge to about 80% capacity within approximately 10 minutes. In some instances, the improved charging rate translates to a vehicle range of about 466 km. For example, the nano‐layer may be configured with both solid electrolyte and conductive carbon components working synergistically to enhance performance. As an example, the nano‐layer may increase energy density from approximately 170 Wh / kg to approximately 240 Wh / kg, extending an electric vehicle’s nominal range by up to approximately 40%.

[0174] In some embodiments, when x = 3, y = 0, z = 1, m = 1, n = 4, and X = P5+, the compound corresponds to the general formula A3PO4. In such cases, representative compounds may include Li₃PO₄, Na₃PO₄, K₃PO₄, Cs₃PO₄, and mixed alkali metal phosphates such as Li^Na₍₃₋^₎PO₄ or Cs^Na₍₃₋^₎PO₄, where a is a real number ranging from 0 to 3. For instance, a 2 wt% Li₃PO₄ nano- coating on bare LFP may be prepared by dissolving 1.19 g of 85% H₃PO₄ and 1.58 g of Li₂C₂O₄ in 100 mL of deionized water, followed by the addition of 60 g of bare LiFePO₄ powder. In some instances, the mixture is stirred and milled into a uniform slurry, then dried at approximately 60 °C, and subsequently sintered under a N₂ / 5% H₂ atmosphere at around 680 °C for 6 hours to yield Li₃PO₄-coated LFP.

[0175] In some embodiments, a 2% LiNa₂PO₄ / C integrated nano-coating on bare LFP may be prepared by combining 1.19 g of 85% H₃PO₄, 3.17 g of LiOAc (lithium acetate), and 6 g of glucose in 100 mL of deionized water with 60 g of bare LiFePO₄ powder. In some cases, this mixture may be stirred and milled to create a homogeneous slurry. In some instances, the slurry may be heated at temperatures between about 65 °C and about 75 °C, such as about 70 °C, while stirring until dried to form a powdered material. For example, the powdered material may be sintered under an N₂ atmosphere at about 700 °C for approximately 4 hours. As an example, the end product comprises LFP with an integrated Li₃PO₄ and carbon nano-coating that beneficially enhances both electronic and ionic conductivity.

[0176] In some embodiments, when x = 4, y = 0, z = 1, m = 2, n = 7, and X = P⁵⁺, the compound comprises A₄P₂O₇. In some cases, the compound may be selected from Li₄P₂O₇, Na4P2O7,K₄P₂O₇, Cs₄P₂O₇, LiaNa(4-b)P₂O₇, or KaNa(4-b)P₂O₇, wherein b is a real number ranging from 0 to 4. In some instances, a 3% Li₄P₂O₇ / C integrated nano-coating on bare LFP may be created by dissolving 1.02 g of H₃PO₄, 1.06 g of Li₂C₂O₄, and 5 g of sucrose in 100 mL of deionized water with 60 g of bare LiFePO₄ powder. For example, the slurry may be heated at about 60 °C while stirring until dried, then sintered under an N₂ atmosphere at about 650 °C for approximately 4 hours. As an example, this produces LFP with an integrated Li₄P₂O₇ and carbon nano-coating that enhances both ionic conductivity and electronic conductivity.Attorney Docket No.67864-701.601

[0177] In some embodiments, when x = 2, y = 1, z = 1, m = 1, n = 4, and X = Si⁴⁺, the compound comprises A₂MSiO₄. In some cases, the compound may be selected from Li₂MgSiO₄, Li₂ZnSiO₄, Li₂CaSiO₄, Na₂MgSiO₄, or Na₂CaSiO₄. In some instances, a 2% Na₂CaSiO₄ / C integrated nano-coating on raw LFP may be prepared by combining 1.84 g of Na₂CO₃, 1.75 g of Ca(NO₃)₂, and 5.5 g of citric acid in 100 mL of deionized water with 2.5 g of tetraethyl orthosilicate and 60 g of raw LiFePO₄ powder. For example, the slurry may be heated to about 60 °C with stirring to form a sol–gel, then dried and sintered in an N₂ atmosphere at about 650 °C for approximately 4 hours. As an example, this process yields LFP with an integrated Na₂CaSiO₄ and carbon nano-coating that improves battery performance characteristics.

[0178] In some embodiments, when x = 4, y = 0, z = 1, m = 1, n = 4, and X = Si⁴⁺, the compound comprises A₄SiO₄. In some cases, the compound may be selected from Li₄SiO₄, Na₄SiO₄, K₄SiO₄, or Cs₄SiO₄. In some instances, a 2% Li₄SiO₄ / C integrated nano-coating on bare LFP may be synthesized by dissolving 4.09 g of LiCH₃COO·2H₂O and 5 g of citric acid in 100 mL deionized water with 2.09 g of tetraethyl orthosilicate and 60 g of bare LiFePO₄ powder. For example, the slurry may be heated at temperatures between about 55 °C and about 65 °C, such as about 60 °C, with stirring to form a sol–gel, which is dried to a powder and sintered under N₂ at about 700 °C for approximately 3 hours. As an example, this produces an integrated Li₄SiO₄ and carbon coating on LFP that enhances battery performance metrics.

[0179] In some embodiments, when x = 3, y = 0, z = 1, m = 1, n = 3, and X = B³⁺, the compound comprises A₃BO₃. In some cases, the compound may be selected from Li₃BO₃, Na₃BO₃, K₃BO₃, Cs₃BO₃, or mixed alkali borates such as Li₂NaBO₃. In some instances, a 1.5% Li₂NaBO₃ / C integrated nano-coating on bare LFP may be developed by combining 1.92 g of LiCH₃COO·2H₂O, 1.28 g of NaCH₃COO·3H₂O, 0.58 g of H₃BO₃, and 6 g of glucose in 100 mL deionized water with 60 g of bare LiFePO₄ powder. For example, the slurry may be heated at about 60 °C with stirring until dry, and the resulting powder may be sintered under N₂ at about 600 °C for approximately 8 hours. As an example, this produces a mixed alkali borate and carbon nano-coating that enhances ionic conductivity due to the mixed‐alkali effect.

[0180] In some embodiments, when x = 1, y = 1, z = 1, and X = P⁵⁺, the compound comprises AMPO₄. In some cases, the compound may be selected from LiMgPO₄, LiZnPO₄, LiCaPO₄, NaMgPO₄, NaZnPO₄, KMgPO₄, or CsMgPO₄. In some instances, a 2% LiZnPO₄ / C integrated nano-coating on LFP may be created by dissolving 0.70 g of H₃PO₄, 0.73 g of LiCH₃COO·2H₂O, 1.57 g of Zn(CH₃COO)₂·2H₂O, and 6 g of glucose in 100 mL deionized water with 60 g of bare LiFePO₄ powder. For example, after heating at temperatures between about 65 °C and about 75 °C, such as about 70 °C, until dry, the powder may be sintered under N₂ at about 650 °C for approximately 5 hours. As an example, this yields LFP / (LZnP / C) withAttorney Docket No.67864-701.601 enhanced performance characteristics due to the presence of both lithium and zinc in the coating material.

[0181] In some embodiments, when x = 2, y = 1, z = 1, m = 1, n = 4, and X = Si⁴⁺, the compound comprises A₂MSiO₄. In some cases, the compound may be selected from Li₂MgSiO₄, Li₂ZnSiO₄, Li₂CaSiO₄, Na₂MgSiO₄, or Na₂ZnSiO₄. In some instances, a 2% Li₂ZnSiO₄ / C integrated nano-coating on bare LFP may be prepared by dissolving 1.43 g of LiCH₃COO·2H₂O, 1.54 g of Zn(CH₃COO)₂·2H₂O, and 5 g of citric acid in 100 mL deionized water with 1.46 g of tetraethyl orthosilicate and 60 g of bare LiFePO₄ powder. For example, after heating at about 70 °C to form a sol–gel and drying, the powder may be sintered under N₂ at about 700 °C for approximately 3 hours. As an example, this produces LFP / (LZnS / C) with improved electrochemical performance due to the silicate‐based coating structure.

[0182] In some embodiments, when x = 2, y = 1, z = 2, m = 1, n = 4, and X = P⁵⁺, the compound comprises A₂M(PO₄)₂. In some cases, the compound may be selected from LiTi(PO4)2, Li2Zr(PO4)2, Na2Zr(PO4)2, K2Zr(PO4)2, or Cs2Zr(PO4)2, In some instances, a 2% Li2Zr(PO4)2 / C integrated nano-coating on bare LFP may be developed by combining 0.54 g of LiOAc (lithium acetate), 0.80 g of H₃PO₄, 1.95 g of Zr(IV) butoxide solution (80%), and 6 g of glucose in 100 mL anhydrous ethanol with 60 g of bare LiFePO4powder. For example, after heating at about 60 °C until dry, the resulting powder may be sintered under N₂ at about 650 °C for approximately 4 hours. As an example, this yields LFP / (LZrP / C) with enhanced performance characteristics due to the presence of zirconium in the phosphate structure.

[0183] In some embodiments, the nano-coating process may be applied to various cathode materials or precursors. In some cases, the cathode material may comprise a phosphate‐based cathode material such as LiFePO4(LFP), LiMnxFe(1-x)PO4, LiMn PO4, LiCoPO4,LiNiPO4, or Li₃V₂(PO₄)₃, where x₁ is a real number ranging from 0 to 1. In some instances, the cathode material may comprise a silicate‐based cathode material such as Li2FeSiO4or Li₂MnSiO4. For example, the process may be adapted for cathode material precursors including phosphate‐based precursors (e.g., FePO4, MnPO4, FexMnyPO4), silicate‐based precursors (e.g., FeSiO3, MnSiO3), or mixed metal compounds. As an example, the coating process may also be applicable to ultra‐ high voltage cathode materials such as LiNi0.5Mn1.5O4, enhancing their performance characteristics.

[0184] In some embodiments, the nano-coated cathode materials exhibit enhanced electrochemical properties compared to uncoated counterparts. In some cases, the improved battery performance includes greater capacity retention at low temperatures, with retention increasing from about 60% to about 80% at -20°C. In some instances, this enhancement translates to a vehicle range expansion from about 420 km to about 560 km in winter conditions.Attorney Docket No.67864-701.601 For example, the nano-coating may provide superfast charging capabilities, allowing batteries to reach about 80% capacity within approximately 10 minutes. As an example, the energy density may increase from about 170 Wh / kg to about 240 Wh / kg, extending an electric vehicle’s nominal range by up to approximately 40%, from about 500 km to about 700 km.

[0185] In some embodiments, for Group IV coatings (y = 2, z = 3), the formula is AxM2(XmOn)3.In some cases, with X = P⁵⁺, one may have A3M2(PO4)3 compounds such as Li3Y2(PO4)3 orNa3Y2(PO4)3, incorporating trivalent cations. In some instances, these compounds provide enhanced ionic conductivity due to their crystalline structure and ion mobility pathways. For example, the three-dimensional framework created by the phosphate groups and metal cations may facilitate alkali ion transport. As an example, the incorporation of Y3+ions may stabilize the structure while maintaining ionic conductivity.

[0186] In some embodiments, a 2% Li3Y2(PO4)3 / C integrated nano-coating on LFP may be synthesized. In some cases, 0.73 g of H3PO4, 2.15 g of Y(NO3)•4H2O, 0.76 g of Li(CH3COO)•2H2O, and 6 g of glucose are dissolved in 100 mL deionized water. In some instances, 60 g bare LFP is added, stirring and milling to obtain a homogeneous slurry. For example, the slurry may be heated at about 70°C while stirring until dry, resulting in a powdered material. As an example, the powder may then be sintered under N3atmosphere at 700°C for 5 hours, yielding LFP / (Li3Y2(PO4)₃ / C ) with enhanced performance characteristics.

[0187] In some embodiments, a 2% LiZr2(PO₄)₃ / C integrated nano-coating on LFP may be created. In some cases, with X = P⁵⁺, x = 1, z = 3, the formula may be AM2(PO4)3(e.g., LiZr2(PO4)3). In some instances, this formulation provides both structural stability from the zirconium and ionic conductivity from the phosphate framework. For example, 0.17 g of LiCH3COO, 0.74 g of H3PO4, 2.43 g of Zr(IV) butoxide (80% solution), and 6 g of glucose may be dissolved in 100 mL anhydrous ethanol. As an example, 60 g bare LFP may be added to this solution, stirring to obtain a homogeneous slurry, heated at about 60°C with stirring until dry, and then sintered under N₂ atmosphere at 650°C for 4 hours, resulting in the LiFePO₄ / (LiZr₂(PO₄)₃ / C) material.

[0188] In some embodiments, the cathode "core" may be a precursor material rather than fully formed LFP. In some cases, polyanion precursors such as FePO₄, amorphous-LFP (a-LFP), Mn^Fe₁₋^PO₄, or amorphous-LMFP (a-LMFP), as well as mixed metal hydroxides and carbonates, may be coated prior to final cathode synthesis. In some instances, this approach allows for more uniform coating integration during the subsequent crystallization process. For example, coating the precursor before full crystallization may lead to better dispersion of the conductive components throughout the cathode material. As an example, this method sometimesAttorney Docket No.67864-701.601 permits more intimate contact between the conductive coating and the active material, enhancing both electronic and ionic conductivity.

[0189] In some embodiments, a 1.5% Li₃PO₄ nano-coating may be applied to FePO₄. In some cases, 2.38 g of Li₂C₂O₄ is dissolved in 100 mL deionized water, and 60 g of FePO₄ precursor is added along with 1.52 g of H₃PO₄, stirring to obtain a homogeneous slurry. In some instances, the slurry is heated at about 60°C with stirring until dry, yielding Li₃PO₄-coated FePO₄ (FP / LP). For example, the precursor mixture may then be used to prepare LFP / (LP / C) cathode material through subsequent lithiation and carbon coating steps. As an example, this two-step approach may result in more uniform distribution of the solid electrolyte coating throughout the final cathode structure.

[0190] In some embodiments, a 1% NaZnPO₄ / carbon precursor nano-coating may be applied to amorphous LFP (a-LFP). In some cases, 0.35 g of H₃PO₄, 0.49 g of NaCH₃COO•3H₂O, 0.79 g of Zn(CH₃COO)₂•2H₂O, and 5 g of glucose are dissolved in 100 mL deionized water. In some instances, 60 g of a-LFP is introduced to this solution, stirred to form a homogeneous mixture, and heated at about 70°C until dry, yielding a-LFP / (NZnP / C). For example, this coated precursor may then be converted to the final cathode through crystallization under controlled atmospheric conditions. As an example, the zinc content in the coating may provide additional electronic conductivity while the sodium phosphate component enhances ionic transport.

[0191] In some embodiments, a 2% Li₄P₂O₇ / carbon precursor nano-coating on a-LMFP may be created. In some cases, 1.17 g of H₃PO₄, 1.21 g of Li₂C₂O₄, and 5 g of sucrose may be dissolved in 100 mL deionized water. In some instances, 60 g of bare a-LMFP is added, stirring to create a homogeneous slurry. For example, the slurry may be heated at about 60°C until dry, forming a powdered material denoted as a-LMFP / (L4P / C). As an example, this intermediate product may be further processed into LMFP / (L4P / C) through appropriate thermal treatment, yielding a cathode with enhanced rate capability.

[0192] In some embodiments, a 2% LiTi₂(PO₄)₃ nano-coating may be applied to Ni₀.₆Co₀.₁Mn₀.₃CO₃. In some cases, 0.17 g of LiCH₃COO, 0.76 g of H₃PO₄, and 1.76 g of Ti(IV) butoxide are dissolved in 50 mL anhydrous ethanol. In some instances, 50 g of Ni₀.₆Co₀.₁Mn₀.₃CO₃ (NMCCO₃) is added, stirred into a homogeneous slurry, and heated at about 60°C until dry to yield NMCCO₃ / LTP. For example, the coated precursor may later be fired to form LNMC / LTP or NNMC / LTP cathodes depending on whether lithium or sodium is used as the alkali metal. As an example, this approach allows for the creation of high-energy cathode materials with the enhanced surface properties provided by the titanium phosphate coating.

[0193] In some embodiments, a 2% NaZr₂(PO₄)₃ nano-coating may be applied to a layered sodium cathode precursor Ni₀.₆₀Fe₀.₂₅Mn₀.₁₅(OH)₂. In some cases, 0.139 g of LiCH₃COO, 0.620Attorney Docket No.67864-701.601 g of H₃PO₄, and 1.76 g of Zr(IV) butoxide are dissolved in 60 mL anhydrous ethanol. In some instances, 50 g of Ni₀.₆₀Fe₀.₂₅Mn₀.₁₅(OH)₂ (NFM(OH)₂) is introduced, stirred into a homogeneous mixture, and dried at about 60°C to yield NFM(OH)₂ / NZrP. For example, this precursor may then be converted to a final NFM / NZrP layered sodium cathode material through appropriate thermal treatment. As an example, the zirconium phosphate coating may improve the cycling stability of the sodium-based cathode by mitigating parasitic reactions with the electrolyte.

[0194] In some embodiments, for comparative purposes, bare-LFP cathode material with no coatings may be produced. In some cases, amorphous LFP precursor (a-LFP) is first prepared by a hydrothermal method involving the reaction of FeSO₄•7H₂O, H₃PO₄, and LiOH•H₂O at 180°C, followed by washing and drying. In some instances, the a-LFP is ball-milled in ethanol and then calcined at 700°C under N₂ / 5% H₂ atmosphere to form crystalline bare LFP. For example, this unmodified material serves as a reference with typical limitations including lower electronic and ionic conductivity. As an example, the performance metrics of the coated materials described above may be evaluated against this baseline to quantify the improvements achieved through the nano-coating approaches.

[0195] In some embodiments, bare-LMFP cathode material may be made for comparison by synthesizing amorphous LiMn0.7Fe0.3PO4(a-LMFP) hydrothermally. In some cases, this involves washing, drying, milling, and then sintering the precursor under N₂ / 5% H₂ at 700°C. In some instances, this bare-LMFP displays the usual constraints of an unmodified phosphate- based cathode. For example, these limitations may include reduced rate capability and potential manganese dissolution issues during cycling. As an example, the comparison of this reference material with coated versions highlights the protective benefits of the solid electrolyte nano- layers in preventing transition metal dissolution and enhancing overall battery performance. EXAMPLES

[0196] The following illustrative examples are representative of embodiments of the compositions, systems, and methods described herein and are not meant to be limiting in any way. Examples of Group I

[0197] The coating material comprises the following formula AxMy(XmOn)z.

[0198] For examples 1a –10, the variables are assigned as follows: X=P5+, x=3, y=0, z=1, m=1, and n=4. This results in the formula A3PO4. Examples of specific compounds following this formula include Li3PO4, Na3PO4, K3PO4, Cs3PO4, LiaNa(3-a)PO4, CsaNa(3-a)PO4(e.g., where "a" is 2), and others.

[0199] Example 1a: Creating a 2wt% Li3PO4nano-coating on bare LFP.Attorney Docket No.67864-701.601

[0200] Add 1.19g of 85% H3PO4and 1.58g of Li2C2O4into a container with 100 mL deionized water. Then add 60g of bare LiFePO4powder to this solution. Stir and mill to create a uniform slurry.

[0201] Heat the slurry at about 60°C while stirring until the slurry dries, forming a powdered material. Following this, sinter the powder under a N2 / 5%H2 atmosphere at 680°C for 6 hours. The end product is Li3PO4-coated LFP, denoted as LFP / LP.

[0202] Example 1b: Creating a 2% LiNa2PO4 / C integrated nano-coating on bare LFP.

[0203] Add 1.19g of 85% H3PO4, 3.17g of LiOAc (lithium acetate), and 6g of glucose into a container with 100 mL of deionized water. Then introduce 60g of bare LiFePO4powder to the solution. Stir and mill to create a homogeneous slurry.

[0204] Heat the slurry at about 70°C while stirring until the slurry dries, resulting in a powdered material. Following this, sinter the powder under an N2atmosphere at 700°C for 4 hours. The end product is LFP with an integrated Li3PO4and carbon nano-coating, denoted as LFP / (LP / C).

[0205] Example 2a: Creating a 2% Na3PO4nano-coating on bare LFP.

[0206] Dissolve 0.72g of H3PO4and 2.99g of NaCH3COO•3H2O in 100 mL of deionized water in a container. Then, add 60g of bare LiFePO4powder to this solution, stirring and milling to form a homogeneous slurry.

[0207] Heat the slurry at about 60°C with continuous stirring until it dries, resulting in a powdered material. Next, sinter it under a N2 / 5%H2atmosphere at 650°C for 5 hours. The resulting product is Na3PO4-coated LFP, denoted as LFP / NP.

[0208] Example 2b: Creating a 2% Na3PO4 / C integrated nano-coating on bare LFP.

[0209] Dissolve 0.72g of H3PO4, 1.47g of Na2C2O4, and 6g of glucose in 100 mL of deionized water in a container. Then, add 60g of bare LiFePO4powder to this solution, stirring and milling to create a homogeneous slurry.

[0210] Heat the slurry at about 70°C while stirring until it dries, forming a powdered material. Then, sinter the powder under an N2atmosphere at 720°C for 3 hours. The resulting product is LFP with an integrated Na3PO4and carbon nano-coating, denoted as LFP / (NP / C).

[0211] Example 3: Creating a 3% Li4P2O7 / C integrated nano-coating on bare LFP.

[0212] As an example, where X=P5+, x=4, y=0, z=1, m=2, and n=7, the formula becomes A4P2O7, leading to variants (e.g., such as Li4P2O7, Na4P2O7, Li2Na2P2O7).

[0213] Dissolve 1.02 g of H3PO4, 1.06g of Li2C2O4, and 5g of sucrose in 100 mL of deionized water in a container. Then add 60g of bare LiFePO4powder to this solution, stirring and milling to produce a homogeneous slurry.Attorney Docket No.67864-701.601

[0214] Heat the slurry at about 60°C while stirring until it dries, forming a powdered material. Then, sinter the powder under an N2atmosphere at 650°C for 4 hours. The end product is LFP with an integrated Li4P2O7and carbon nano-coating, denoted as LFP / (L4P / C).

[0215] Example 4: Creating a 2% Na2CaSiO4 / C integrated nano-coating on raw LFP.

[0216] In this example, X=Si⁴⁺, x=2, y=1, z=1, m=1, and n=4, the formula becomes A₂MSiO₄, giving rise to variants such as Li₂MgSiO₄, Na₂ZnSiO₄, and Na₂CaSiO₄.

[0217] Dissolve 1.84g of Na2CO3, 1.75g of Ca(NO3)2, and 5.5g of citric acid in 100 mL of deionized water in a beaker. Next, add 2.5g of tetraethyl orthosilicate (Si(OCH2CH3)4) and 60g of raw LFP powder to this solution, stirring continuously to produce a homogeneous slurry.

[0218] Heat the slurry to about 60°C with stirring until it solidifies to form a sol-gel. Dry the sol-gel to obtain a powdered material. Subsequently, sinter the powder in an N2atmosphere at 650°C for 4 hours. The final result is LFP with an integrated Na2CaSiO4and carbon nano- coating, denoted as LFP / (NCS / C).

[0219] Example 5: 2% Li4SiO4 / C integrated nano-coating on bare LFP.

[0220] In this example, where x=4, y=0, z=1, m=1, and n=4, the formula is A4SiO4, such as Li4SiO4, Na4SiO4, LixNa4-xSiO4, and so on.

[0221] Dissolve 4.09g of LiCH3COO•2H2O, and 5g of citric acid in 100mL deionized water in a container. Add 2.09g tetraethyl orthosilicate (Si(OCH2CH3)4) and 60g bare LFP powder to the solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring to form a sol-gel. Dry the sol-gel, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 700°C for 3 hours to produce integrated Li4SiO4and carbon nano-coating on LFP, denoted as LFP / (L4S / C).

[0222] Example 6: 1.5% Li2NaBO3 / C integrated nano-coating on bare LFP.

[0223] For X=B3+, where x=3, y=0, z=1, m=1 and n=3, the formula is A3BO3, such as Li3BO3, Na3BO3, K3BO3LixNa3-xBO3, and so on.

[0224] Dissolve 1.92g of LiCH3COO•2H2O, 1.28g of NaCH3COO•3H2O, 0.58g H3BO3, and 6g of glucose in 100mL deionized water in a container. Add 60g bare LFP powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 600°C for 8 hours to produce integrated Li2NaBO3 and carbon nano-coating on LFP, denoted as LFP / (L2NB / C).

[0225] Example 7: 2% Na3PO4 / C integrated nano-coating on LFMP.

[0226] Nano-coating of group I for coating different polyanion cathode materials, such as LFMP, Li2FeSiO4.Attorney Docket No.67864-701.601

[0227] Dissolve 0.72g of H3PO4, 1.47g of Na2C2O4, and 6g of glucose in 100mL deionized water in a container. Add 60g bare LiMn0.7Fe0.3PO4powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2 atmosphere at 700°C for 5 hours to produce integrated Na3PO4and carbon nano-coating on LMFP, denoted as LMFP / (NP / C). Examples of Group II: where y=1 and z=1, the formula is AxMXmOn

[0228] The following examples 11-13 are for X=P5+, x=1, m=1, n=4, the formula is AMPO4, such as LiMgPO4, LiZnPO4, LiCaPO4, NaMgPO4, NaZnPO4, KMgPO4, CsMgPO4, and so on.

[0229] Example 8: 2% LiZnPO4 / C integrated nano-coating on LFP.

[0230] Dissolve 0.70g of H3PO4, 0.73g of LiCH3COO•2H2O, 1.57g of Zn(CH3COO)2•2H2O, and 6g of glucose in 100mL deionized water in a container. Add 60g bare LiFePO4powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 650°C for 5 hours to produce integrated LiZnPO4and carbon nano-coating on LFP, denoted as LFP / (LZnP / C).

[0231] Example 9: 2% NaMgPO4 / C integrated nano-coating on LMFP.

[0232] Dissolve 0.83g of H3PO4, 1.15g of NaCH3COO•3H2O, 1.81g of Mg(CH3COO)2•4H2O, and 6g of glucose in 100mL deionized water in a container. Add 60g bare LiMn0.7Fe0.3PO4powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 650°C for 5 hours to produce integrated NaMgPO4and carbon nano-coating on LMFP, denoted as LMFP / (NMP / C).

[0233] Example 10: 2% Li2ZnSiO4 / C integrated nano-coating on bare LFP.

[0234] For X=Si4+, where x=2, m=1, and n=4, the formula is A2MSiO4, such as Li2MgSiO4, Li2ZnSiO4, Na2MgSiO4, and so on.

[0235] Dissolve 1.43g of LiCH3COO•2H2O, 1.54g of Zn(CH3COO)2•2H2O, and 5g of citric acid in 100mL deionized water in a container. Add 1.46g tetraethyl orthosilicate (Si(OCH2CH3)4) and 60g bare LFP powder to the solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring to form a sol-gel. Dry the sol-gel, resulting in a powdered material. Subsequently, sinter the powder under N2 atmosphere at 700°C for 3 hours to produce integrated Li2ZnSiO4and carbon nano-coating on LFP, denoted as LFP / (LZnS / C).Attorney Docket No.67864-701.601 Group III: where y=1 and z=2, the formula becomes AxM(XmOn)2

[0236] The following example 11 is for X=P5+, where x=2, m=1, and n=4, the formula becomes A2M(PO4)2, such as Li2Ti(PO4)2, Li2Zr(PO4)2, Na2Zr(PO4)2, Na2Zr(PO4)2, K2Zr(PO4)2, Cs2Zr(PO4)2, and so on.

[0237] Example 11: 2% Li2Zr(PO4)2 / C integrated nano-coating on bare LFP.

[0238] Dissolve 0.54g of LiCH3COO, 0.80g of H3PO4, 1.95g of Zr(IV) butoxide solution (80%), and 6g of glucose in 100mL anhydrous ethanol. Add 60g bare LFP powder to the ethanol solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 650°C for 4 hours to produce integrated Li2Zr(PO4)2and carbon nano-coating on LFP, denoted as LFP / (LZrP / C). Group IV: where y=2 and z=3, the formula is AxM2(XmOn)3

[0239] The following example 12 is for X=P5+, in one case of x=3 and z=3, the formula is A3M2(PO4)3, such as Li3Al2(PO4)3, Li3V2(PO4)3, Li3Y2(PO4)3Li3La2(PO4)3, Na3Al2(PO4)3, Na3Y2(PO4)3, and so on.

[0240] Example 12: 2% Li3Y2(PO4)3 / C integrated nano-coating on LFP.

[0241] Dissolve 0.73g of H3PO4, 2.15g of Y(NO3)•4H2O, 0.76g of Li(CH3COO)•2H2O, and 6g of glucose in 100mL deionized water in a container. Add 60g bare LFP powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 700°C for 5 hours to produce integrated Li3Y2(PO4)3and carbon nano-coating on LFP, denoted as LFP / (LYP / C).

[0242] Example 13: 2% LiZr2(PO4)3 / C integrated nano-coating on LFP.

[0243] In this example, For X=P5+, in another case of x=1 and z=3, the formula is AM2(PO4)3, such as LiZr2(PO4)3, LiTi2(PO4)3, NaZr2(PO4)3, NaTi2(PO4)3 and so on.

[0244] Dissolve 0.17g of LiCH3COO, 0.74g of H3PO4, 2.43g of Zr(IV) butoxide solution (80%), and 6g of glucose in 100mL anhydrous ethanol. Add 60g bare LFP powder to the ethanol solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in a powdered material. Subsequently, sinter the powder under N2atmosphere at 650°C for 4 hours to produce integrated LiZr2(PO4)3and carbon nano-coating on LFP, denoted as LFP / (LZrP3 / C).

[0245] In examples 14 and 15, the core may be cathode material precursors, including polyanions (e.g. FePO4, amorphous-LiFePO4(or a-LFP), MnxFe1-xPO4, and amorphous- LiMnxFe1-xPO4(or a-LMFP), mixed metal hydroxides and mixed metal carbonates.Attorney Docket No.67864-701.601

[0246] Example 14: 1.5% Li3PO4nano-coating on the precursor FePO4.

[0247] In this example, the core may be cathode material precursors, including polyanions (e.g. FePO4, amorphous-LiFePO4(or a-LFP), MnxFe1-xPO4, and amorphous-LiMnxFe1-xPO4(or a- LMFP), mixed metal hydroxides and mixed metal carbonates.

[0248] Dissolve 2.38g of Li2C2O4in 100mL deionized water in a container. Add 60g of the precursor material FePO4 into the solution, followed by adding 1.52g of H3PO4, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in Li3PO4nano-coated FePO4, denoted as FP / LP.

[0249] The precursor mixture FP / LP may be used as the precursor to prepare LFP / (LP / C) cathode material.

[0250] Example 15: 1%NaZnPO4 / carbon precursor nano-coating on a-LFP.

[0251] Dissolve 0.35g of H3PO4, 0.49g of NaCH3COO•3H2O, 0.79g of Zn(CH3COO)2•2H2O, and 5g of glucose in 100mL deionized water in a container. Add 60g of the precursor a-LFP powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 70°C with stirring until dry, resulting in NaZnPO4 / C precursor and carbon precursor coated a-LFP, denoted as a-LFP / (NZnP / C).

[0252] The precursor mixture a-LFP / (NZnP / C) may be used as the precursor to prepare LFP / (NZnP / C) cathode material.

[0253] Example 16: 2%Li4P2O7 / carbon precursor nano-coating on a-LMFP.

[0254] Dissolve 1.17g of H3PO4, 1.21g of Li2C2O4, and 5g of sucrose in 100mL deionized water in a container. Add 60g of bare a-LMFP powder to the solution, stirring and milling to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in Li4P2O7 / carbon precursor-coated a-LMFP, denoted as a-LMFP / (L4P / C).

[0255] The precursor mixture a-LMFP / (L4P / C) may be used as the precursor to prepare LMFP / (L4P / C) cathode material.

[0256] Example 17: 1.5%LiZr2(PO4)3nano-coating on Ni0.8Co0.1Mn0.1(OH)2(NMC(OH)2).

[0257] Dissolve 0.10g of LiCH3COO, 0.46g of H3PO4, and 1.52g of Zr(IV) butoxide solution (80%) in 50mL anhydrous ethanol. Add 50g of Ni0.8Co0.1Mn0.1(OH)2(NMC(OH)2) powder to the ethanol solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in LiZr2(PO4)3 precursor-coated Ni0.8Co0.1Mn0.1(OH)2, denoted as NMC(OH)2 / LZrP.

[0258] The precursor mixture NMC(OH)2 / LZrP may be used as the precursor to prepare LNMC / LZrP lithium cathode material and NNMC / LZrP sodium cathode material.

[0259] Example 18: 2%LiTi2(PO4)3nano-coating on Ni0.6Co0.1Mn0.3CO3.Attorney Docket No.67864-701.601

[0260] Dissolve 0.17g of LiCH3COO, 0.76g of H3PO4, and 1.76g of Ti(IV) butoxide in 50mL anhydrous ethanol. Add 50g of Ni0.6Co0.1Mn0.3CO3(NMCCO3) powder to the ethanol solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in LiTi2(PO4)3 precursor-coated Ni0.6Co0.1Mn0.3CO3 denoted as NMCCO3 / LTP.

[0261] The precursor mixture NMCCO3 / LTP may be used as the precursor to prepare LNMC / LTP lithium cathode material and NNMC / LTP sodium cathode material.

[0262] Example 19: 2%NaZr2(PO4)3nano-coating on layered sodium cathode material precursor Ni0.60Fe0.25Mn0.15(OH)2.

[0263] Dissolve 0.139g of LiCH3COO, 0.620g of H3PO4, and 1.76g of Zr(IV) butoxide in 60mL anhydrous ethanol. Add 50g of Ni0.60Fe0.25Mn0.15(OH)2(NFM(OH)2) powder to the ethanol solution, stirring to obtain a homogeneous slurry. Heat the slurry at about 60°C with stirring until dry, resulting in LiZr2(PO4)3-coated Ni0.60Fe0.25Mn0.15(OH)2precursor mixture powder, denoted as NFM(OH)2 / NZrP.

[0264] The precursor powder NFM(OH)2 / LZrP may be used as the precursor to prepare NFM / NZrP layered sodium cathode material. Comparative example 1: Preparation of bare-LFP cathode material

[0265] First, amorphous LFP precursor, denoted as a-LFP, is prepared by a hydrothermal method. In the method, 55.6g of FeSO4•7H2O, 23.06g of 85%H3PO4, and 25.2g of LiOH•H2O are introduced into a hydrothermal reactor containing 500mL deionized water, all while stirring under N2atmosphere. The reactor is sealed airtight. Heat the reactor to 180°C while stirring, and maintain the reactor at 180°C for 4hours, followed by cooling of the reactor to room temperature. Subsequently, the solution is filtrated, and the solid cake undergoes three washes with deionized water the collected solid cake is then dried at about 80°C in an oven, resulting in a-LFP precursor.

[0266] Next, a-LFP is dispersed in 60mL anhydrous ethanol to form a slurry. The slurry is subjected to ball milling at 400 rpm for 3 hours, and the resulting slurry is dried to obtain finely milled a-LFP powder.

[0267] Finally, the fine a-LFP powder is placed in a ceramic crucible and transferred into a tube furnace. The crucible undergoes heating in the tube furnace under N2 / 5%H2 atmosphere to 700°C and maintain this temperature for 3 hours. The furnace is then allowed to cool down to room temperature to obtain bare-LFP cathode material. Comparative example 2: Preparation of bare-LMFP cathode material

[0268] First, amorphous LiMn0.7Fe0.3PO4precursor, denoted as a-LMFP, is prepared by a hydrothermal method. In the method, 23.66g of MnSO4•H2O, 16.68g of FeSO4•7H2O, 23.06g ofAttorney Docket No.67864-701.601 85%H3PO4, and 25.18g of LiOH•H2O are introduced into a hydrothermal reactor containing 500mL deionized water, all while stirring under N2atmosphere. The reactor is sealed airtight. Heat the reactor to 180°C while stirring and maintain the reactor at 180°C for 4hours, followed by cooling of the reactor to room temperature. Subsequently, the solution is filtrated, and the solid cake undergoes three washes with deionized water the collected solid cake is then dried at about 80°C in an oven, resulting in a-LMFP precursor.

[0269] Next, a-LMFP is dispersed in 60mL anhydrous ethanol to form a slurry. The slurry is subjected to ball milling at 400 rpm for 3 hours, and the resulting slurry is dried to obtain finely milled a-LMFP powder.

[0270] Finally, the fine a-LMFP powder is placed in a ceramic crucible and transferred into a tube furnace. The crucible undergoes heating in the tube furnace under N2 / 5%H2atmosphere to 700°C and maintain this temperature for 3 hours. The furnace is then allowed to cool down to room temperature to obtain bare-LMFP cathode material. Comparative example 3: Benchmark using Commercial LFP / C Material

[0271] For further comparison, a commercially available carbon-coated lithium iron phosphate (LFP / C) material was obtained and utilized as a benchmark. This commercially sourced material was used as received for subsequent electrochemical evaluation and is designated herein as Comp Ex3. Comparative Examples and Results

[0272] The cathode active materials prepared in Comparative Examples 1 and 2 were evaluated using coin cells. The performance of each material was assessed based on their capacity at various charge / discharge rates. These data provide a direct comparison of the effectiveness of the different cathode active material preparation methods.

[0273] The coin cells used for evaluation are assembled with an electrolyte consisting of 1 M LiPF6, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, in a volume ratio of 1:1:1. The anode of the coin cells is composed of lithium metal foil. The coin cells also comprise a separator made of Celgard 2400.

[0274] The cathode of the coin cells is a composite material that includes the cathode active material, conductive carbon C65, and PVDF binder. The weight proportion of the cathode composite is 95% cathode active material, 2% conductive carbon C65, and 3% PVDF binder.

[0275] These results indicate that cathode active material prepared in Ex3, Ex8, Ex12, and Ex13 exhibited the highest rate performance, indicating that this preparation method may be ideal for maximizing the rate capability of active cathode materials by the nano-coating.Attorney Docket No.67864-701.601

[0276] Other variations in the proportions or makeup of the coin cells may be employed within the scope of this invention.

[0277] The capacity retention values shown in Table 1 under headers designated "X C / Y C" (e.g., "1C / 0.2C", "5C / 0.2C") are calculated as the percentage ratio of the discharge capacity measured at the X C rate divided by the discharge capacity measured at the Y C rate.

[0278] As demonstrated by the data in Table 1, cathode active materials comprising the nano- coatings described herein (Examples 1a-13) generally exhibited improved electrochemical performance compared to uncoated materials (Comparative Examples 1-2). For instance, at a C / 5 discharge rate, capacities for the coated examples ranged from approximately 137 mAh / g (Ex1a) to 159 mAh / g (Ex5). At a 1C discharge rate, capacities for the coated examples ranged from approximately 116 mAh / g (Ex1a) to 147 mAh / g (Ex13), with several examples surpassing the capacity of the commercial LFP / C material (Comp Ex4). Furthermore, at a high discharge rate of 5C, capacities for the coated examples ranged from approximately 74 mAh / g (Ex1a) to 128 mAh / g (Ex12), again with multiple examples exceeding the commercial reference. Capacity retention at 1C relative to 0.2C performance for the coated examples was observed between approximately 85% (Ex1a, Ex2a) and 93% (Ex8, Ex12), while retention at 5C relative to 0.2C ranged from approximately 54% (Ex1a) to 81% (Ex8, Ex11, Ex12).

[0279] In some embodiments, cathode active materials comprising the nano-layer described herein exhibit discharge capacity when measured at a C / 5 rate (a rate corresponding to a theoretical 5-hour discharge), as shown in Table 1. In some cases, the specific capacity at the C / 5 rate for examples comprising the nano-layer ranges from approximately 68 mAh / g to approximately 239 mAh / g. In some instances, this capacity is observed across various nano- layer compositions applied to LFP (Lithium Iron Phosphate) or LMFP (Lithium Manganese Iron Phosphate) core materials. For example, a capacity between about 100 mAh / g and about 200 mAh / g may be achieved at the C / 5 rate. As an example, certain compositions may achieve capacities near the upper end of this range, such as approximately 159.4 mAh / g observed for Example 5 (LFP / (L4S / C)).

[0280] In some embodiments, the nano-coated cathode active materials maintain discharge capacity at a 1C rate (a rate corresponding to a theoretical 1-hour discharge) (see Table 1). In some cases, the specific discharge capacity measured at 1C for examples comprising the nano- layer ranges from approximately 58 mAh / g to approximately 221 mAh / g. In some instances, capacity retention at 1C relative to performance at 0.2C (a rate corresponding to a theoretical 5- hour discharge) is maintained within a range from approximately 42% to approximately 140%. For example, the 1C discharge capacity may be between about 100 mAh / g and about 180Attorney Docket No.67864-701.601 mAh / g. As an example, the capacity retention at 1C (relative to 0.2C) may be between about 70% and about 110%, with values up to about 93% observed in Examples 8 and 12.

[0281] In some embodiments, the nano-coated cathode active materials demonstrate discharge capacity even at a high 5C rate (a rate corresponding to a theoretical 12-minute discharge) (see Table 1). In some cases, the specific discharge capacity measured at 5C for examples comprising the nano-layer ranges from approximately 37 mAh / g to approximately 192 mAh / g. In some instances, capacity retention at 5C relative to 0.2C performance is observed within a range from approximately 27% to approximately 122%. For example, the 5C discharge capacity may be between about 60 mAh / g and about 150 mAh / g. As an example, the capacity retention at 5C (relative to 0.2C) may be between about 40% and about 100%, as shown for Examples 8, 11, and 12 which exhibited retention up to about 81%, indicating suitability for certain applications.

[0282] Table 1: Electrochemical Performance Comparison of Coated and Uncoated Cathode Active Materials Solid Capacity (mAh / g) and Relative Capacity Carbon C th d A tiv El tr l t CAttorney Docket No.67864-701.601 Solid Capacity (mAh / g) and Relative Capacity Carbon Cathode Active Electrolyte Cprepara on; a va ue o or / n caes no ex erna car on source was a e .

[0285] Capacity retention values ("1C / 0.2C" and "5C / 0.2C") are calculated as the percentage ratio of the discharge capacity measured at the higher C-rate (1C or 5C) divided by the discharge capacity measured at the 0.2C rate.

[0286] While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It may be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure.

Claims

Attorney Docket No.67864-701.601 CLAIMS WHAT IS CLAIMED IS:

1. A nano-layer, comprising an ionically conductive material comprising a compound of formula AxMy(XmOn)z, wherein: a. A is selected from the group consisting of Li+, Na+, K+, or Cs+, and a combination thereof; b. M is selected from the group consisting of divalent cations of Mg2+, Ca2+, Ba2+, Zn2+, Co2+, Ni2+, and Mn2+, trivalent cations of Al3+, B3+, Y3+, and V3+, rare earth metal ions, and tetravalent cations of Zr4+and Ti4+, and a combination thereof; c. X comprises P5+, Si4+, or B3+; d. x is an integer of 1 to 4; e. y is an integer of 0 to 2; f. z is an integer of 1 to 3, g. m is an integer of 1 to 2; and h. n is an integer of 2 to 7 wherein the nano-layer coats or is on top of a cathode material or a cathode material precursor.

2. The nano-layer of claim 1, wherein x is 3, y is 0, z is 1, m=1, n=4, and X=P5+.

3. The nano-layer of claim 1, wherein the compound is Li3PO4, Na3PO4, K3PO4, Cs3PO4, LiaNa(3-a)PO4, or CsaNa(3-a)PO4, wherein a is a real number ranging from 0 to 3.

4. The nano-layer of claim 1, wherein x is 4, y is 0, z is 1, m=2, n=7, and X=P5+.

5. The nano-layer of claim 1, wherein the compound is Li4P2O7, Na4P2O7, K4P2O7, Cs4P2O7, LiaNa(4-a)P2O7, or KaNa(4-a)P2O7, wherein a is a real number ranging from 0 to 4.

6. The nano-layer of claim 1, wherein x is 2, y is 0, z is 1, m=1, n=3, and X=Si4+.

7. The nano-layer of claim 1, wherein the compound is Li2SiO3, Na2SiO3, K2SiO3, or Cs2SiO3.

8. The nano-layer of claim 1, wherein x is 4, y is 0, z is 1, m=2, n=4, and X=Si4+.

9. The nano-layer of claim 1, wherein the compound is Li4SiO4, Na4SiO4, K4SiO4, or Cs4SiO4.

10. The nano-layer of claim 1, wherein x is 1, y is 0, z is 1, m=1, n=2, and X=B3+.

11. The nano-layer of claim 1, wherein the compound is LiBO2, NaBO2, KBO2, or CsBO2.Attorney Docket No.67864-701.601 12. The nano-layer of claim 1, wherein x is 3, y is 0, z is 1, m=1, n=3, and X=B3+.

13. The nano-layer of claim 1, wherein the compound is Li3BO3, Na3BO3, K3BO3, or Cs3BO3.

14. The nano-layer of claim 1, wherein x is 1, y is 1, z is 1, and X=P5+.

15. The nano-layer of claim 1, wherein the compound is LiMgPO4, LiZnPO4, LiCaPO4, NaMgPO4, NaZnPO4, KMgPO4, or CsMgPO4.

16. The nano-layer of claim 1, wherein x is 2, y is 1, z is 1, m is 1, n is 4, and X=Si4+.

17. The nano-layer of claim 1, wherein the compound is Li2MgSiO4, Li2ZnSiO4, Li2CaSiO4, Na2MgSiO4, or Na2ZnSiO4.

18. The nano-layer of claim 1, wherein x is 2, y is 1, z is 2, m is 1, n is 4, and X=P5+.

19. The nano-layer of claim 1, wherein the compound is Li2Ti(PO4)2, Li2Zr(PO4)2, Na2Zr(PO4)2, Na2Ti(PO4)2, K2Zr(PO4)2, or Cs2Zr(PO4)2.

20. The nano-layer of claim 1, wherein x is 3, y is 2, z is 3, and X=P5+.

21. The nano-layer of claim 1, wherein the compound is Li3Al2(PO4)3, Li3V2(PO4)3, Li3Y2(PO4)3, Li3La2(PO4)3, Na3Al2(PO4)3, or Na3Y2(PO4)3.

22. The nano-layer of claim 1, wherein x is 1, y is 2, z is 3, m is 1, n is 4, and X=P5+.

23. The nano-layer of claim 1, wherein the compound is LiZr2(PO4)3, or LiTi2(PO4)3.

24. The nano-layer of any of the preceding claims, wherein the cathode material comprises a phosphate-based cathode material.

25. The nano-layer of claim 24, wherein the phosphate-based cathode material comprises LiFePO4(LFP), LiMnx1Fe(1-x1)PO4, LiMnPO4, LiCoPO4, LiNiPO4, or Li3V2(PO4)3, wherein x1 is a real number ranging from 0 to 1.

26. The nano-layer of any of the preceding claims, wherein the cathode material comprises a silicate-based cathode material.

27. The nano-layer of claim 26, wherein the silicate-based cathode material comprises Li2FeSiO4, or Li2MnSiO4.

28. The nano-layer of any of the preceding claims, wherein the cathode material comprises a cathode material precursor.

29. The nano-layer of claim 28, wherein the cathode material precursor comprises a phosphate-based cathode material precursor.

30. The nano-layer of claim 29, wherein the phosphate-based cathode material precursor comprises FePO4, MnPO4, Fex2Mny2PO4, or CoPO4, wherein x2is a real number ranging from 0 to 1, and wherein y2 is a real number ranging from 0 to 1, wherein x2+ y2is equal to 1.Attorney Docket No.67864-701.601 31. The nano-layer of any of claims 28-30, wherein the cathode material precursor comprises a silicate-based cathode material precursor.

32. The nano-layer of claim 31, wherein the silicate-based cathode material precursor comprises FeSiO3, or MnSiO3.

33. The nano-layer of any of claims 28-32, wherein the cathode material precursor comprises a mixed metal carbonate.

34. The nano-layer of claim 33, wherein the mixed metal carbonate comprises Nix3Coy3Mnz3CO3, wherein x3is a real number ranging from 0 to 1, wherein y3is a real number ranging from 0 to 1, and wherein z3is a real number ranging from 0 to 1, wherein x3+ y3+ z3is equal to 1.

35. The nano-layer of claim 33 or claim 34, wherein the mixed metal carbonate comprises a mixed metal hydroxide.

36. The nano-layer of claim 35, wherein the mixed metal hydroxide comprises Nix4Coy4Niz4(OH)2, wherein x4is a real number ranging from 0 to 1, wherein x4is a real number ranging from 0 to 1, and wherein x4is a real number ranging from 0 to 1, wherein of x4+ y4+ z4is equal to 1.

37. The nano-layer of any of the preceding claims, further comprising one or more sodium cathode precursors.

38. The nano-layer of any of the preceding claims, wherein the cathode material comprises a layered oxide cathode material.

39. The nano-layer of claim 38, wherein the layered oxide cathode material comprises LiCoO2-based, Nickel Manganese Cobalt-based (e.g., NMC-based), Nickel Cobalt Aluminum-based (e.g., NCA-based), or Li-rich manganese oxide-based cathode materials.

40. The nano-layer of any of the preceding claims, wherein the cathode material comprises an ultra-high voltage cathode material such as LiCoPO4, LiNi0.5Mn1.5O4, Li-rich manganese-based cathode materials, a 5.0V cathode material, or a combination thereof.

41. The nano-layer of any of the preceding claims, wherein the ultra-high voltage cathode material comprises LiNi0.5Mn1.5O4.

42. The nano-layer of claim 40 or claim 41, wherein the ultra-high voltage cathode material further comprises one or more sodium cathode materials.

43. The nano-layer of any of the preceding claims, wherein the cathode material precursor is used to form a cathode material.Attorney Docket No.67864-701.601 44. A method for surface coating of polyanion cathode active materials with a nano- layer, enhancing both ionic and electronic transport properties, the method comprising: a. providing a cathode material of any of the preceding claims; and b. applying a nano-layer of any of the preceding claims to the cathode material of (a).

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