Method for forming a doped metal oxide film for interface control on an electrode

Abstract

The invention provides a new solution: deposition of a doped metal oxide layer on the electrode by ALD or CVD to form an artificial interface to protect the electrode from fast decay electrochemical behavior. The metals discussed here are group IVA-VIA elements (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) and the dopants here include B, Al, C, Si, N, P, S, allowing the oxide network to be porous, which can be advantageous due to the presence of the dopant. It is also desirable that the film is thin, possibly discontinuous, and lithium ion conductive enough so that the addition of this thin film interface allows fast lithium ion migration at the interface between the electrode and the electrolyte.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 043,611, filed June 24, 2020, and U.S. Provisional Patent Application No. 63 / 044,008, filed June 25, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0003] During the initial few cycles of lithium-ion batteries, a solid electrolyte interface (SEI) is observed to form on the anode and / or cathode due to electrolyte decomposition at the electrolyte / electrode interface. The initial capacity loss of lithium-ion batteries is due to lithium consumption during this SEI formation. Furthermore, the formed SEI layer is inhomogeneous and unstable, failing to effectively passivate the electrode surface to prevent degradation of the electrode active materials due to continuous electrolyte decomposition. Physical cracks may appear in the SEI layer during battery cycling, and lithium dendrites may form, leading to short circuits and subsequent thermal runaway. In addition, the SEI layer creates a barrier that makes lithium-ion insertion into the electrode more difficult.

[0004] In current designs, lithium-ion batteries have a (lithium) metal oxide, phosphate, or fluoride coating (e.g., Al) on the surface of the electrode and / or electrode active material, achieved through wet coating, dry coating, or sputtering of a continuous film of metal oxide and / or phosphate. x O y Li x M y PO z M = Nb, Zr, Al, Ti, etc., or AlM x F yLithium-containing films (M = W, Y, etc.) are used to stabilize the interface between the electrode and the electrolyte. Lithium-containing films are well-known for their use as surface coatings for electrode materials in lithium-ion battery applications. Examples of lithium-containing films include LiPON, lithium phosphate, lithium borate, lithium borate phosphate, lithium niobate, lithium titanate, lithium zirconium oxide, etc. Surface coating of electrodes using ALD / CVD technology is the preferred method for forming the desired solid electrolyte interface film, thus avoiding the formation of these unstable layers. However, vapor deposition of lithium-containing films is difficult to implement due to the lack of suitable lithium precursors for mass production: most lithium precursors are non-volatile or not stable enough, and they may contain undesirable impurities. Another important application of interface films is the formation of solid electrolyte materials used in solid-state batteries. Solid-state batteries are solvent-free systems that offer longer lifespans, faster charging times, and higher energy densities than conventional lithium-ion batteries. Solid-state batteries are considered the next technological stage in battery development. With ALD / CVD technology, even uniform and conformal electrode / electrolyte interface films can be obtained on complex structures such as 3D batteries.

[0005] Silicon anodes are also used in interfacial thin films. Silicon is considered the next-generation anode in lithium-ion battery development, in contrast to graphite anodes (as opposed to Li). + The same potential level (relative to Li 0.05 V) + At Li 0.2 V), silicon is superior to graphite anode (372 mAh g). -1 It offers a higher specific capacity (3600 mAh g). -1 The main drawback of silicon anodes is that their volume expands by up to 300% during charge / discharge, leading to SEI instability and physical cracks in the electrodes.

[0006] The application interface of thin films can be extended to lithium metal anode technology. Lithium metal anodes are considered post-lithium-ion batteries (LIBs) because they can provide at least three times the theoretical capacity compared to LIBs. Lithium metal has also attracted much attention due to its high capacity (10 times that of graphite), smaller battery size, and simpler processing. However, uncontrolled lithium metal surfaces can lead to the growth of Li dendrites, causing short circuits and ultimately fires.

[0007] For next-generation cathode active materials, much research has focused on identifying and developing metal oxide cathode materials. Among a wide range of layered oxides, Ni-rich cathode materials like NMC (lithium nickel manganese cobalt oxide) and NCA (lithium nickel cobalt aluminum oxide) are currently the most promising candidates for practical applications. However, Ni-rich cathode materials tend to become amorphous when high voltages are applied. One of the main drawbacks of these metal oxide materials is the continuous dissolution of transition metals, especially nickel, due to parasitic reactions between the cathode material and the electrolyte. This leads to structural degradation of the cathode active material, along with the release of gas (O2) at the electrode / electrolyte interface during battery charging. Furthermore, dissolved nickel ions migrate to the anode side, and their deposition on the anode surface triggers rapid decomposition of the SEI at the anode, ultimately leading to battery failure.

[0008] Spinel cathode materials have been extensively studied due to their high rate performance and low or zero cobalt content. One of the main problems with spinel cathode materials such as LMO (lithium manganese oxide) and LNMO (lithium nickel manganese oxide) is the presence of divalent manganese ions (2MnO2) during battery charging. 3+ → Mn 4+ + Mn 2+ The dissolution of the electrolyte occurs primarily at the electrode / electrolyte interface, followed by redeposition on the anode side and destruction of the anode's SEI through the same mechanism as Ni-rich cathode materials.

[0009] To address interface issues between the electrolyte and cathode electrode, such as transition metal dissolution and excessive electrolyte decomposition, thin film deposition can be applied to the cathode and / or cathode material. For example, US 8535832 B2 discloses the wet coating of metal oxides (Al2O3, Bi2O3, B2O3, ZrO2, MgO, Cr2O3, MgAl2O4, Ga2O3, SiO2, SnO2, CaO, SrO, BaO, TiO2, Fe2O3, MoO3, MoO2, CeO2, La2O3, ZnO, LiAlO2, or combinations thereof) onto cathode active materials containing Ni, Mn, and Co. US9543581 B2 describes the dry coating of amorphous Al2O3 onto precursor particles of cathode active materials containing Ni, Mn, and Co. US 9614224 B2 describes the use of sputtering to deposit Li... x PO y Mn zCoatings. US9837665 B2 describes a lithium phosphorus nitride (LiPON) thin film coating on a cathode active material comprising Li, Mn, Ni, and an oxygen-containing compound having at least one of Ti, Fe, Ni, V, Cr, Cu, and Co, using sputtering. US9196901 B2 describes an Al2O3 thin film coating on a cathode laminate and cathode active material comprising Co, Mn, V, Fe, Si, or Sn and being an oxide, phosphate, silicate, or a mixture of two or more of these, using atomic layer deposition (ALD). US 10224540 B2 describes an Al2O3 thin film coating on a porous silicon anode using ALD. US10177365 B2 describes an AlW coating on a cathode active material comprising LiCoO2 using ALD. x F y Or AlW x F y C z Thin film coating. US 9531004 B2 describes a hybrid thin film coating on an anode material assembly using the ALD method, comprising a first layer of Al2O3, TiO2, SnO2, V2O5, HfO2, ZrO2, ZnO and a second layer of a fluoride-based coating, a carbide-based coating, and a nitride-based coating, wherein the anode material assembly consists of lithium titanate Li. (4+x) Ti5O 12 , where 0 ≦ x ≦ 3 (LTO), graphite, silicon, silicon-containing alloys, tin-containing alloys, and combinations thereof. Summary of the Invention

[0010] This invention provides a solution by depositing a doped metal oxide layer onto the cathode or cathode active material via ALD or CVD, forming an artificial interface on the electrode to protect it from rapid decay electrochemical behavior. These doped metal oxide layers reduce excessive electrolyte decomposition at the electrode / electrolyte interface during SEI formation, thereby reducing capacity loss in the initial few cycles. The presence of this doped metal oxide layer also reduces the dissolution of transition metal cations in the cathode active material caused by parasitic reactions between the electrolyte and the cathode active material, and consequently reduces their redeposition on the anode. This improves the electrochemical activity of the battery. As discussed above, other types of films, especially pure metal oxides such as Al₂O₃, have been proposed. However, this type of material acts as an ion insulator and therefore does not yield optimal electrochemical performance for the resulting cathode and battery. By selecting transition metals that can undergo oxidation state changes, the composition of the doped metal oxide layer takes into account the need for Li ion diffusion. The corresponding metal oxides are deposited using individual dopant chemicals and / or using gaseous metal precursors containing dopants such as C, Si, Sn, B, Al, N, P, and / or S. The deposition conditions are chosen to produce a doped metal oxide film, rather than a metal oxide film. While not wishing to be bound by any particular theory, doped metal oxide films are generally considered "low-quality" films unsuitable for most applications. For example, such materials are typically low-density due to the porosity caused by the dopant elements, particularly carbon and phosphorus. However, it may be precisely this porosity that facilitates the balance between protecting the cathode and allowing Li ion migration. It is also possible that the addition of first-row transition elements (preferably Mn, Ni, Co, Fe, Cu) can increase the ionic conductivity of the film and thereby improve its electrochemical performance.

[0011] The invention can be further understood by referring to the following description, which is a non-limiting and exemplary embodiment of the listed statements:

[0012] 1. A cathode or cathode active material comprising at least a surface coating of a doped metal oxide film, preferably, the metal being selected from niobium, tantalum, vanadium, zirconium, titanium, hafnium, tungsten, molybdenum, chromium, and combinations thereof.

[0013] 2. The cathode or cathode active material as described in statement 1, wherein the doped metal oxide film is a film containing metal, oxygen and carbon or a film containing metal, oxygen and phosphorus.

[0014] 3. The cathode or cathode active material as described in statement 1, wherein the doped metal oxide film is a doped niobium oxide film.

[0015] 4. The cathode or cathode active material as described in statement 1, wherein the doped metal oxide film is a film containing niobium, oxygen and carbon or a film containing niobium, oxygen and phosphorus.

[0016] 5. The cathode or cathode active material as described in any one of statements 1-4, wherein the cathode or cathode active material is only partially coated with the doped metal oxide film.

[0017] 6. The cathode or cathode active material as described in any one of statements 1-5, wherein the doped metal oxide film has an average thickness of 0.02 nm to 10 nm, preferably 0.1 nm to 5 nm, and most preferably 0.2 nm to 2 nm.

[0018] 7. The cathode or cathode active material as described in any one of statements 1-4, wherein the doped metal oxide film has a carbon atom percentage of 5% to 50%, preferably 10% to 30%, and most preferably 15% to 25%.

[0019] 8. The cathode or cathode active material as described in any one of statements 3-7, wherein the doped metal oxide film has a refractive index of 1.5 to 2.5, preferably 1.6 to 2.1, and most preferably 1.7 to 2.0.

[0020] 9. The cathode or cathode active material as described in statement 1, wherein the doped metal oxide has an average atomic composition of M. x O y D z M is a transition metal or a group II-A to VI-B element, O is oxygen, and D is a dopant atom other than lithium, M or O. Preferably, D is selected from C, Si, Sn, B, Al, N, P or S, and x = 10% to 60%, y ranges from 10% to 60%, and z ranges from 5% to 50%, preferably from 10% to 30%.

[0021] 10. The cathode or cathode active material as described in statement 9, wherein the cathode or cathode active material is only partially coated with the doped metal oxide film.

[0022] 11. The cathode or cathode active material as described in statement 9 or 10, wherein the doped metal oxide film has an average thickness of 0.02 nm to 10 nm, preferably 0.1 nm to 5 nm, and most preferably 0.2 nm to 2 nm.

[0023] 12. The cathode or cathode active material as described in any one of statements 9-11, wherein the doped metal oxide film has a carbon atom percentage of 5% to 50%, preferably 10% to 30%, and most preferably 15% to 25%.

[0024] 13. The cathode or cathode active material as described in any one of statements 9-12, wherein the doped metal oxide film has a refractive index of 1.5 to 2.5, preferably 1.6 to 2.1, and most preferably 1.7 to 2.0.

[0025] 14. A proton exchange membrane battery comprising a cathode or cathode active material as described in any one of statements 1-13.

[0026] 15. A method for coating a cathode or cathode active material with a doped metal oxide film, the method comprising the following steps:

[0027] a1 exposes the cathode or cathode active material to chemical precursor vapor, and

[0028] b1. Deposit the doped metal oxide film onto the cathode or cathode active material.

[0029] 16. The method as described in statement 15, further comprising step a2 of exposing the cathode or cathode active material to the co-reactant.

[0030] 17. The method as described in statement 16, wherein step a1, in which the cathode or cathode active material is exposed to the chemical precursor vapor, and step a2, in which the cathode or cathode active material is exposed to the co-reactant, are performed sequentially.

[0031] 18. The method as described in statement 17, further comprising step a1i of purging the chemical precursor vapor prior to step a2 of exposing the cathode or cathode active material to the co-reactant.

[0032] 19. The method as described in statement 18, wherein step b1, depositing the doped metal oxide film onto the cathode or cathode active material, includes an atomic layer deposition step.

[0033] 20. The method as described in statement 18, wherein step b1, depositing the doped metal oxide film onto the cathode or cathode active material, includes a chemical vapor deposition step.

[0034] 21. The method described in statements 15-20, wherein the co-reactant is an oxygen source, such as O2, O3, H2O, H2O2, NO, NO2, N2O, or NO x Oxygen-containing silicon precursors, oxygen-containing tin precursors, phosphate esters such as trimethyl phosphate, diethyl aminophosphate, or sulfate esters.

[0035] 22. The method as described in any one of statements 15-19, wherein the doped metal oxide film produced by step b1 has an average atomic composition of M. x Oy D z M is a transition metal or a group II-A to VI-B element, preferably selected from niobium, tantalum, vanadium, tungsten, molybdenum, chromium, hafnium, zirconium, titanium and combinations thereof, O is oxygen, and D is a dopant atom other than lithium, M or O, preferably selected from C, Si, Sn, B, Al, N, P or S, and wherein x = 0.1-0.3, y = 0.3-0.65, and z = 0.1-0.3.

[0036] 23. The method as described in any one of statements 15-22, wherein one or more of these steps are repeated.

[0037] 24. The method as described in any one of statements 15-23, wherein the temperature of the chemical precursor vapor and / or the cathode or cathode active material is 200°C or lower, preferably 50°C to 200°C, more preferably 100°C to 200°C, and even more preferably 100°C to 150°C.

[0038] 25. The method of any one of statements 15-24, wherein the cathode active material, or the cathode active material in the cathode, is selected from the group consisting of: a) layered oxides, such as Ni-rich cathode materials like NMC (lithium nickel manganese cobalt oxide) and NCA (lithium nickel cobalt aluminum oxide); b) spinel cathode materials, such as LMO (lithium manganese oxide) and LNMO (lithium nickel manganese oxide); c) olivine-structured cathode materials, particularly the olivine phosphate family, such as LCP (lithium cobalt phosphate) and LNP (lithium nickel phosphate); and combinations thereof. Attached Figure Description

[0039] To further understand the nature and purpose of the invention, reference should be made to the following detailed description in conjunction with the accompanying drawings, in which similar elements are given the same or similar reference numerals, and in the drawings:

[0040] Figure 1 The long-term cycling performance of NbOC film deposition on NMC622 powder using NbCp(=NtBu)(NMe2)2(“Nab”) / H2O is shown at 1C (initial 3 pre-cycles at 0.2C).

[0041] Figure 2 Normalized long-term cycling performance of NbOC thin film deposition on NMC622 powder using a powdered ALD (PALD) reactor with NbCp(=NtBu)(NMe2)2(“Nab”) / H2O is shown (normalized to their initial discharge capacity at 1C).

[0042] Figure 3The C-rate performance of NbOC film deposition on NMC622 powder using a powdered ALD (PALD) reactor with NbCp(=NtBu)(NMe2)2(“Nab”) / H2O is shown.

[0043] Figure 4 Normalized C-rate performance (normalized to their initial discharge capacity at 0.2C) of NbOC thin film deposition on NMC622 powder using a powdered ALD (PALD) reactor with NbCp(=NtBu)(NMe2)2 (“Nab”) / H2O is shown.

[0044] Figure 5 The original and NbOC formed by powder ALD (PALD)-100C-20 cycles using NbCp(=NtBu)(NMe2)2(“Nab”) / H2O are shown before and after battery cycling;

[0045] Figure 6 The long-term cycling performance of NbOC thin film deposition on NMC622 electrode (EALD) in ALD region using NbCp(=NtBu)(NMe2)2 (“Nab”) / H2O is shown at 1C (initial 3 pre-cycles at 0.2C).

[0046] Figure 7 Normalized long-term cycling performance (normalized to their initial discharge capacity at 1C) of NbOC thin film deposition on NMC622 electrodes (EALD) in the ALD region using NbCp(=NtBu)(NMe2)2 (“Nab”) / H2O is shown.

[0047] Figure 8 The C-rate performance of NbOC films on NMC622 electrodes using NbCp(=NtBu)(NMe2)2(“Nab”) / H2O is shown;

[0048] Figure 9 The normalized C-rate performance (normalized to their initial discharge capacity at 0.2C) of NbOC films on NMC622 electrodes (EALD) in the ALD region using NbCp(=NtBu)(NMe2)2 (“Nab”) / H2O is shown.

[0049] Figure 10 The long-term cycling performance of NbOCP films on an NMC622 electrode (ECVD) in the CVD region using Nb(=NtBu)(NMe2)2(OEt) (“Nau”), TMPO and O3 is shown (initial 3 pre-cycles at 0.2C).

[0050] Figure 11 Normalized long-term cycling performance (normalized to their initial discharge capacity at 1C) of NbOCP films on NMC622 electrodes (ECVD) in the CVD region using Nb(=NtBu)(NMe2)2(OEt) (“Nau”) / TMPO / O3 is shown.

[0051] Figure 12 The C-rate performance of NbOCP thin film deposition on an NMC622 electrode (ECVD) in the CVD region using Nb(=NtBu)(NMe2)2(OEt) (“Nau”) / TMPO / O3 is shown.

[0052] Figure 13 Normalized C-rate performance (normalized to their initial discharge capacity at 0.2C) of NbOCP thin film deposition on NMC622 electrodes (ECVD) in the CVD region using Nb(=NtBu)(NMe2)2(OEt) (“Nau”) / TMPO / O3 is shown.

[0053] Figure 14 The long-term cycling performance of ZrOC films on LNMO electrodes in the ALD region using "ZrCp", such as ZrCp(NMe2)3 / O3, is shown (3 initial pre-cycles at 0.2C).

[0054] Figure 15 Normalized long-term cycling performance (normalized to their initial discharge capacity at 1C) of ZrOC films on LNMO electrodes in the ALD region using “ZrCp”, such as ZrCp(NMe2)3 / O3.

[0055] Figure 16 The C-rate performance of ZrOC films on LNMO electrodes using "ZrCp", such as ZrCp(NMe2)3 / O3, is shown.

[0056] Figure 17 The normalized C rate performance (normalized to their initial discharge capacity at 0.2C) of ZrOC films on LNMO electrodes in the ALD region using ZrCp(NMe2)3 / O3 is shown. Detailed Implementation

[0057] This disclosure provides a solution for forming interfaces on electrodes to protect them from rapidly decaying electrochemical behavior. The electrode interface is formed on the cathode active material before or after it is bonded to the final cathode. The doped metal oxide layer is formed using one or more volatile precursors via chemical vapor deposition (CVD) or atomic layer deposition (ALD), the one or more volatile precursors being simultaneously, sequentially, and / or through pulsed supply of a precursor vapor phase.

[0058] As used in this article, "doped metal oxide" and "doped metal oxide film" refer to transition metal oxide films with one or more additional elements, such that the atomic ratio is M. x O y D z , where M = aggregate of one or more transition metals, O is oxygen, and D is aggregate of other elements (such as carbon and phosphorus) in the doped film. Typically, x ranges from 10% to 60%, y ranges from 10% to 60%, and z ranges from 5% to 50%, preferably from 10% to 30%.

[0059] Preferably, M is a transition metal that forms one or more stable ions with incompletely filled d orbitals. In particular, M can be one or more of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, or W.

[0060] Preferably, at least one D is selected from C, Si, Sn, B, N, P, or S, more preferably carbon and / or phosphorus. Other possible D may include Al, Mn, Co, Fe, and Cu. Particularly preferred doped metal oxide layers include C-containing titanium oxides, Si-containing titanium oxides, P-doped titanium oxides, C-containing zirconium oxides, Si-containing zirconium oxides, P-doped zirconium oxides, C-containing niobium oxides, Si-containing niobium oxides, and P-doped niobium oxides.

[0061] Doped metal oxide films are formed by CVD or ALD methods to deposit a doped metal oxide layer onto the cathode active material before, during, or after the cathode active material is bonded to the final cathode. The doped metal oxide film can be a continuous film that completely coats the cathode active material, such as by powder ALD of the powdered cathode active material before it is incorporated into the cathode. The film can also be discontinuous, either by limiting film growth through controlled deposition conditions or by ensuring that only a portion of its surface is exposed to the CVD or ALD deposition process due to the bonding of the cathode active material to the cathode. Typically, the doped metal oxide film has an average thickness of 0.125 to 10 nm, such as 0.125 nm to 1.25 nm, preferably 0.3 nm to 4 nm.

[0062] Doped metal oxide deposits can be deposited on electrodes, such as those composed of:

[0063] ● Layered oxide structure, preferably “NMC” (lithium nickel manganese cobalt oxide), NCA (lithium nickel cobalt aluminum oxide) or LNO (lithium nickel oxide).

[0064] ● Spinel, preferably LNMO (lithium nickel manganese oxide) or LMO (lithium manganese oxide);

[0065] ● Olivine (lithium-metal phosphate, where the metal can be iron, cobalt, or manganese);

[0066] ● Carbon anode form, such as graphite, doped or undoped;

[0067] ● Silicon anode,

[0068] ● Tin anode,

[0069] ● Silicon-tin anode, or

[0070] ● Lithium metal.

[0071] Deposition can be performed on electrode active material powder, porous electrode active material, electrode active material of different shapes, or on a pre-formed electrode (where the electrode active material may have been associated with conductive carbon and / or binder and may have been supported by current collector foil).

[0072] In a lithium-ion battery, the "cathode" refers to the positive electrode in the electrochemical cell (battery), where the cathode material undergoes reduction during charging through the insertion of electrons and lithium ions. During discharging, the cathode material is oxidized by releasing electrons and lithium ions. Lithium ions move from the cathode to the anode within the electrochemical cell via the electrolyte, and vice versa, while electrons migrate through the external circuitry. The positive electrode typically consists of a positive electrode active material (i.e., a lithium-ionized layered metal oxide), a conductive carbon black agent (acetylene black SuperC65, Super P), and a binder (PVDF, CMC).

[0073] "Cathode active materials" are a key component of the cathode (positive electrode) in a battery cell. Cathode materials are, for example, multi-metal oxide materials in which cobalt, nickel, and manganese, forming a layered crystalline structure, are embedded with lithium. An example of a cathode active material is layered lithium-nickel-manganese-cobalt oxide (LiNi). x Mn y Co z O2), spinel lithium manganese oxide (LMn2O4) and olivine iron phosphate (LiFePO4).

[0074] Doped metal oxide films are formed by vaporization using CVD or ALD processes, employing one or more chemical precursors that facilitate the final film formation. Any one or more suitable precursors can be selected based on their known suitability for forming metal oxides or even doped metal oxides for other applications. Typically, known precursors for metal oxides are used in the unique CVD or ALD process parameters for producing doped metal oxides. These parameters include lower vapor and / or substrate temperatures compared to metal oxide deposition, to intentionally produce, for example, “low-quality” films with a carbon content exceeding 1%; relatively low refractive indices compared to metal oxides; and / or higher porosity levels (and therefore lower densities) compared to the corresponding metal oxides.

[0075] Under optimized deposition conditions, a wide range of precursors are suitable for forming doped metal oxides.

[0076] Preferred Group IVA metal precursors are:

[0077] ● M(OR)4, where each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred choices being M(OMe)4, M(OiPr)4, M(OtBu)4, and M(OsBu)4.

[0078] ● M(NR 1 R 2 )4, where each R 1 and R 2 Independently, it is a C1-C6 carbon chain (straight or branched), with the most preferred being M(NMe2)4, M(NMeEt)4, and M(NEt2)4.

[0079] ● ML(NR 1 R 2 )3, where L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, and each R 1 and R 2 Independently, it is a C1-C6 carbon chain (straight chain or branched chain), with the most preferred being MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, and MCp. (NMe2)3, MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, MCp (NMe2)3, M(iPrCp)(NMe2)3, M(sBuCp)(NMe2)3, M(tBuCp)(NMe2)3, N(secPenCp)(NMe2)3, M(nPrCp)(NMe2)3

[0080] ● ML(OR)3, where L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, or cyclooctadienyl, and each R is independently a C1-C6 carbon chain (straight or branched), with MCp(OiPr)3, M(MeCp)(OiPr)3, M(EtCp)(OEt)3, and MCp being the most preferred. (OEt)3, M(iPrCp)(NMe2)3, M(sBuCp)(NMe2)3, M(tBuCp)(NMe2)3, N(secPenCp)(NMe,)3, M(nPrCp)(NMe2)3

[0081] Preferred group VA metal precursors are:

[0082] ● M(OR)5, where each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred being M(OEt)5, M(OiPr)5, M(OtBu)5, and M(OsBu)5.

[0083] ● M(NR 1 R 2 )5, where each R 1 and R 2 Independently, it is a C1-C6 carbon chain (straight or branched), with the most preferred being M(NMe2)5, M(NMeEt)5, and M(NEt2)5.

[0084] ● ML(NR 1 R 2 ) x Where x = 3 or 4, L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, or NR, and each R 1 and R 2 Independently, it is a C1-C6 carbon chain (straight chain or branched chain), with the most preferred being MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, and MCp. (NMe2)3, M(=NtBu)(NMe2)3, M(=NtAm)(NMe2)3, M(=NtBu)(NEt2)3, M(=NtBu)(NEtMe)3, M(=NiPr)(NEtMe)3.

[0085] ● M(=NR 1 )L(NR 2 R 3 ) xWhere x = 1 or 2, L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, and each R 1 and R 2 and R 3 Independently, the carbon chains are C1-C6, with the most preferred choices being MCp(=NtBu)(NMe2)2, M(MeCp)(N=tBu)(NMe2)2, M(EtCp)(N=tBu)(NMe2)2, and MCp. (=NtBu)(NMe2)2, MCp(=NtBu)(NEtMe)2, M(MeCp)(N=tBu)(NEtMe)2, M(EtCp)(N=tBu)(NEtMe)2.

[0086] ● ML(OR) x Where x = 3 or 4, L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, or NR, wherein each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred being MCp(OiPr)3, M(MeCp)(OiPr)3, M(EtCp)(OEt)3, and MCp (OEt)3 M(=NtBu)(OiPr)3, M(=NtAm)(OiPr)3,

[0087] ● ML(OR) x (NR 1 R 2 ) yWhere x and y are independently equal to 1 or 2, L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, or NR, wherein each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred being MCp(OiPr)2(NMe2), M(MeCp)(OiPr)2(NMe2), M(EtCp)(OEt)2(NMe2), M(=NtBu)(OiPr)2(NMe2), M(=NtBu)(OiPr)(NMe2)2, M(=NtBu)(OiPr)2(NMe2), M(=NtBu)(OiPr)2(NEt Me), M(=NtBu)(OiPr)2(NEt2), M(=NtBu)(OEt)2(NMe2), M(=NtBu)(OEt)2(NEtMe), M(=NtBu)(OEt)2(NEt2), M(=NiPr)(OiPr)2(NMe2), M(=NiPr)(O iPr)2(NMe2)2, M(=NiPr)(OiPr)2(NEtMe), M(=NiPr)(OiPr)2(NEt2), M(=NiPr)(OEt)2(NMe2), M(=NiPr)(OEt)2(NEtMe), or M(=NiPr)(OEt)2(NEt2).

[0088] Preferred VIA group metal precursors are:

[0089] ● M(OR)6, where each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred being M(OEt)5, M(OiPr)5, M(OtBu)5, and M(OsBu)5.

[0090] ● M(NR 1 R 2 )6, where each R 1 and R 2 Independently, it is a C1-C6 carbon chain (straight or branched), with the most preferred being M(NMe2)6, M(NMeEt)6, and M(NEt2)6.

[0091] ● M(NR 1 R 2 ) x L y Where x and y are independently equal to 1 to 4, L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, or NR, and each R 1 and R 2Independently, it is a C1-C6 carbon chain (straight chain or branched chain), with the most preferred being MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, and MCp. (NMe2)3, M(=NtBu)2(NMe2)2, M(=NtAm)2(NMe2)2, M(=NtBu)(NEt2)2

[0092] ● M(OR) x (NR 1 R 2 ) y L z ML, where x, y, and z are independently equal to 0 to 4, and L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, or NR, wherein each R is independently a C1-C6 carbon chain (straight or branched), with the most preferred being MCp(OiPr)3, M(MeCp)(OiPr)3, M(EtCp)(OEt)3, M(=NtBu)2(OiPr)2, M(=NtAm)2(OiPr)2, M(=NtBu)2(OtBu)2, M(=NiPr)2(OtBu)2, M(=NtBu)2(OiPr)2, and M(=NiPr)2(OiPr)2.

[0093] ● M(=O) x L y , where x, y and z are independently equal to 0 to 4, L represents an imide in the form of unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, amide or NR, wherein each R is independently a C1-C6 carbon chain (straight or branched), most preferably M(=O)2(OtBu)2, M(=O)2(OiPr)2, M(=O)2(OsecBu)2, M(=O)2(OsecPen)2, M(=O)2(NMe2)2, M(=O)2(NEt2)2, M(=O)2(NiPr2)2, M(=O)2(NnPr2)2, M(=O)2(NEtMe)2, M(=O)2(NPen2)2.

[0094] Doped metal oxide films can be formed using a single precursor or a combination of two or more precursors, optionally together with an oxidative co-reactant (if desired). A single precursor can contribute all elements found in the final film, including oxygen and one or more dopant elements D. Alternatively, the metal can originate from one precursor, the oxygen from an oxidative co-reactant, and one or more dopant elements D from a second precursor. For example, the metal precursors listed above can be combined with a second precursor that contributes or increases the amount of one or more dopant elements D, wherein one or both precursors are deposited in an oxidizing environment to produce some metal oxide in the final film. In other cases, the second precursor supplies dopant D and oxidizes the metal to produce metal oxide in the final film. Those skilled in the art can select suitable one or more precursors and co-reactants from those known in the art to produce a doped metal oxide film with a desired composition when used under optimized deposition conditions, thereby “tuning” the levels of the metal oxide and one or more dopant elements D. Exemplary guidance for various precursor options includes:

[0095] ● Oxygen can come from oxygen sources such as O2, O3, H2O, H2O2, NO, NO2, N2O, or NO. x

[0096] ● Oxygen can come from dopant sources, such as oxygen-containing silicon precursors, oxygen-containing tin precursors, phosphate esters such as trimethyl phosphate, diethyl aminophosphate, or sulfate esters.

[0097] ● Nitrogen can come from N sources such as N2, NH3, N2H4, mixtures containing N2H4, alkyl hydrazine, NO, NO2, N2O, or NO x

[0098] ● Nitrogen can come from dopant sources such as nitrogen-containing silicon precursors, nitrogen-containing tin precursors, or phosphate esters such as diethyl aminophosphate.

[0099] ● Carbon can come from C sources, such as hydrocarbons, carbon-containing silicon precursors, carbon-containing tin precursors, carbon-containing boron precursors, carbon-containing aluminum precursors, carbon-containing phosphorus precursors, phosphate esters such as trimethyl phosphate, diethyl aminophosphate, or sulfate esters.

[0100] ● Silicon can be derived from Si sources, such as silanes or silicon-containing organometallic precursors.

[0101] ● Tin can be derived from Sn sources, such as tinanes or tin-containing organometallic precursors.

[0102] ● Aluminum can be derived from Al sources, such as aluminum alkanes (including alkylaluminanes) or aluminum-containing organometallic precursors.

[0103] ● Phosphorus can be derived from phosphine, including organophosphine or phosphate esters such as trimethyl phosphate or diethyl aminophosphate.

[0104] ● Sulfur can come from S sources, such as sulfur, S8, H2S, H2S2, SO2, organic sulfites, sulfates, or sulfur-containing organometallic precursors.

[0105] ● The first row of transition metals can be derived from known organometallic compounds or other precursors suitable for vapor deposition.

[0106] Example

[0107] Examples 1-5: Deposition and electrochemical properties of NbOC films deposited on NMC622 powder at 100°C and 150°C

[0108] Experimental conditions for deposition / film formation:

[0109] Deposition was carried out on NMC622 powder using a fluidized bed reactor under the following experimental conditions:

[0110] Reactor temperature x°C

[0111] Reactor pressure: 1 Torr

[0112] Precursor tank T: 115°C

[0113] Precursor tank P: 50 torpedoes

[0114] Number of loops: y

[0115] Pulse sequence:

[0116] Nb precursor: 30 s

[0117] Purge: 20 s

[0118] H2O: 5 s

[0119] Purge: 5 seconds

[0120] In these examples 1-5, the Nb precursor is NbCp(=NtBu)(NMe2)2 (“NAB”). The number of cycles on the NMC622 electrode or NMC powder is typically limited to 5-20 ALD cycles, corresponding to a thickness of approximately 1.5 to 4 Å, insufficient for film composition analysis. Therefore, this type of characterization is performed on films deposited after 300 ALD cycles. The corresponding thickness and film composition are as follows:

[0121] ● Process temperature: 150°C GPC approximately 0.27 Å. Nb: approximately 24%, O: approximately 47%, C: approximately 27%, N < DL

[0122] ● Process temperature: 100°C GPC approximately 0.78 Å. Nb: approximately 25%, O: approximately 48%, C: approximately 27%, N < DL

[0123] At 200°C and above, the refractive index of these films is approximately 1.7, compared to 2.25 for Nb₂O₅ films.

[0124] Electrochemical characterization:

[0125] Experimental conditions:

[0126] - Cathode material NMC622

[0127] - The test electrode consists of 88:7:5 wt% active cathode material: carbon black (C65): PVDF (Solef5130), which is then cast onto the Al current collector using a scraper (200 microns).

[0128] - Five or twenty NbCp(=NtBu)(NMe2)2 / H2O ALD cycles at the process temperatures provided in the diagram.

[0129] - Electrolyte: 1M LiPF6 in EC: EMC (1:1 wt)

[0130] - Li metal is used as an anode material

[0131] - Electrode loading is approximately 5 mg / cm 2 40 micrometers thick

[0132] - 1C = 180 mA g -1 At 3.0 and 4.3 V (relative to Li + Batteries that cycle between / Li)

[0133] like Figure 1 As can be seen, compared with the original NMC622 electrode, the NbOC powder-coated NMC622 electrode, especially the sample with fewer ALD cycles (NbCp(=NtBu)(NMe2)2 / H2O powder ALD-100C-5 cycles), showed a higher initial capacity at 0.2C. When 20 ALD cycles were performed, the initial capacity became very close to the original initial capacity, likely due to the thicker NbOC film. Subsequent battery cycling showed good long-term stability at 1C. Figure 2 As shown, the NbOC powder-coated NMC622 electrode effectively retains its capacity, giving at least >92.5% capacity retention after 80 cycles, while the original electrode only retains 84%.

[0134] like Figure 3 and Figure 4As shown, when comparing C-rate performance, the NbOC powder-coated NMC622 electrode exhibits higher capacity across the entire C-rate range (0.2C to 10C) compared to the original electrode, even for samples with 20 ALD cycles. This improvement is likely due to the carbon doping effect, which makes other metal oxide films such as Al2O3 (where cell performance deteriorates after 10 ALD cycles) more porous compared to other metal oxide films (S.-H. Lee et al., US 9196901 B2, 2012). Porosity allows for better Li+ ion migration compared to dense metal oxide films.

[0135] based on Figure 5 Analysis of the scanning electron micrographs shown indicates that the presence of NbOC deposits / partial films allows the material morphology to be maintained, while the original material tends to degrade, with the presence of NiO. x The different grain sizes, which may be due to the dissolution of nickel in the NMC particles and its subsequent return to the electrode surface, correlate well with the improved electrochemical performance discussed above.

[0136] Examples 6-9: Deposition and electrochemical properties of NbOC films deposited on NMC622 electrodes at 50°C, 75°C, and 100°C

[0137] Experimental conditions for sediment formation:

[0138] Deposition was carried out in a thermal ALD reactor on an NMC622 electrode under the following experimental conditions:

[0139] Reactor temperature x°C

[0140] Reactor pressure: 1 Torr

[0141] Precursor tank T: 95°C

[0142] Precursor tank P: 50 torpedoes

[0143] Number of loops: y

[0144] Pulse sequence:

[0145] Nb precursor: 30 s

[0146] Purge: 20 s

[0147] H2O: 5 s

[0148] Purge: 5 seconds

[0149] The Nb precursor is NbCp(=NtBu)(NMe2)2 (“NAB”). The number of cycles on NMC622 electrodes or NMC powder is typically limited to 5–100 ALD cycles, corresponding to thicknesses of approximately 1.1–85 Å, insufficient for film composition analysis. Therefore, this type of characterization is performed on films deposited after 300 ALD cycles. The corresponding thickness and film composition are as follows:

[0150] - Process temperature: 100°C GPC approximately 0.23 Å. Nb: approximately 17%, O: approximately 40%, C: approximately 42%, N < DL

[0151] - Process temperature: 75°C GPC approximately 0.28 Å. Nb: approximately 20%, O: approximately 45%, C: approximately 34%, N < DL

[0152] - Process temperature: 50°C GPC approximately 0.85 Å. Nb: approximately 16%, O: approximately 35%, C: approximately 48%, N < DL

[0153] At 275°C and above, the refractive index of these films is approximately 1.7, compared to 2.22 for Nb₂O₅ films.

[0154] Electrochemical characterization:

[0155] Experimental conditions:

[0156] - Cathode material NMC622

[0157] - The electrode consists of 88 : 7 : 5 wt% active material: carbon black (C65): PVDF (Solef 5130), which is then cast onto the Al current collector using a scraper (200 microns).

[0158] - Five NbCp(=NtBu)(NMe2)2 / H2O ALD cycles at the process temperatures provided in the figure.

[0159] - Electrolyte: 1M LiPF6 in EC: EMC (1:1 wt)

[0160] - Li metal is used as an anode material

[0161] - Electrode loading is approximately 5 mg / cm 2 40 micrometers thick

[0162] - 1C = 180 mA g -1 At 3.0 and 4.3 V (relative to Li +Batteries that cycle between / Li)

[0163] Long-term cycling stability of NbOC thin film coated NMC622 electrode ( Figure 6 This not only shows a high discharge capacity at 1C during the initial cycle (4th cycle) independent of ALD temperature, but also indicates a capacity retention of at least >92% after 80 battery cycles, while for the original NMC622 electrode ( Figure 7 An 84% retention rate was observed. Temperature dependence was also observed; for this experimental cell, ALD at 100°C was the optimal temperature for obtaining better long-term cycling stability under these conditions.

[0164] In terms of rate performance, the NbOC film deposition on the NMC622 electrode enables the electrode to exhibit higher capacity at 0.2C - 5C compared to the original electrode. Figure 8 and Figure 9 At 10°C, only the NbCp(=NtBu)(NMe2)2 / H2O electrode ALD performed at 100°C showed a higher capacity than the original electrode. This was observed in long-term cycling tests (…). Figure 6 As demonstrated in [reference needed], this C-rate result further confirms that the optimal ALD temperature in these experiments is 100°C.

[0165] Examples 10-13: Deposition and electrochemical properties of NbOC films deposited on NMC622 electrodes using Nb(=NtBu)(NMe2)2(OEt) / H2O at 75°C, 100°C, 125°C, and 150°C.

[0166] A similar experiment was conducted by replacing NAB with the precursor Nb(=NtBu)(NMe2)2(OEt) (“NAU”). The resulting membrane exhibited the following properties:

[0167] ● 3-61 Å thickness

[0168] ● Refractive index from 2.06 to 2.28

[0169] ● Atomic composition of 300 circulating membranes:

[0170] ○ Process temperature: 150°C GPC approximately 0.66 A. Nb: approximately 25%, O: approximately 60%, C: approximately 11%, N: approximately 2%.

[0171] ○ Process temperature: 125°C GPC approximately 1.69 A. Nb: approximately 30%, O: approximately 64%, C: approximately 4%, N: approximately 1%.

[0172] ○ Process temperature: 100°C GPC approximately 2.25 A. Nb: approximately 27%, O: approximately 57%, C: approximately 14%, N: approximately 1%.

[0173] ○ Process temperature: 75°C GPC approximately 3.07 A. Nb: approximately 25%, O: approximately 58%, C: approximately 15%, N: approximately 2%.

[0174] These electrodes exhibit improvements in electrochemical performance similar to those of electrodes with NAB-derived membranes.

[0175] Examples 14-15: Chemical vapor deposition and electrochemical properties of NbOCP films deposited on NMC622 electrodes

[0176] NbOCP deposition was performed under the following experimental conditions:

[0177] Sedimentary conditions and characterization:

[0178] Reactor temperature 100°C - 150°C

[0179] Reactor pressure: 1 Torr

[0180] Nb precursor tank T: 95°C

[0181] Nb precursor tank P: 10 torpedoes

[0182] Nb precursor bubbling FR: 50 sccm

[0183] TMPO container temperature: 30°C

[0184] TMPO can P: 10 pallets

[0185] TMPO bubbling FR: 50 sccm

[0186] Reaction time: y min (specified in the graph)

[0187] Precursor flow rate:

[0188] Nb precursor: 5 sccm

[0189] TMPO: 5 sccm

[0190] O3: 100 sccm

[0191] The niobium precursor is Nb(=NtBu)(NMe2)2(OEt). The corresponding thickness and film composition are as follows: at 100°C, t is approximately 2.1 nm. Nb: 29.6%, O: 58.0%, C: 7.8%, P: 2.6%, N < DL; at 150°C, t is approximately 1.8 nm. Nb: approximately 24.3%, O: approximately 60.1%, C: approximately 7.6%, P: 6.4%, N < DL.

[0192] Electrochemical characterization:

[0193] - Cathode material NMC622

[0194] - The electrode consists of 88 : 7 : 5 wt% active material: carbon black (C65): PVDF (Solef 5130), which is then cast onto the Al current collector using a scraper (200 microns).

[0195] - NbOP deposited via electrode CVD using the following:

[0196] - CVD process temperature = 100°C-150°C; duration: 1 and 2 min

[0197] - Electrolyte: 1M LiPF6 in EC: EMC (1:1 wt)

[0198] - Li metal is used as an anode material

[0199] - Electrode loading is approximately 5 mg / cm 2 40 μm thickness

[0200] - 1C = 180 mA g -1 At 3.0 and 4.3 V (relative to Li + Batteries that cycle between / Li)

[0201] like Figure 10 and Figure 11 As shown, the NbOCP-coated NMC622 electrode exhibits increased initial capacity at 0.2C compared to the original NMC622 electrode. For subsequent cycling, the NbOCP-coated NMC622 electrode demonstrates significantly better cycling performance, maintaining >95% retention after 80 cell cycles at 1C for the Nb(=NtBu)(NMe2)2(OEt) / TMPO / O3 ECVD-150°C-1 min electrode. Compared to the original NMC622 electrode, the NMC622 electrode with the NbOCP film exhibits higher capacity up to 5C at low and medium C rates. Figure 12 and Figure 13 ).

[0202] Examples 16-19: Deposition and electrochemical properties of ZrOC films deposited on LNMO electrodes

[0203] Sedimentary conditions and characterization:

[0204] Reactor temperature 75°C - 150°C

[0205] Reactor pressure: 1 Torr

[0206] Zr precursor tank T: 100°C

[0207] Zr precursor tank P: 20 torpedoes

[0208] Zr precursor bubbling FR: 40 sccm

[0209] Reaction time: y min (specified in the graph)

[0210] Precursor flow rate:

[0211] Zr precursor: 2 sccm

[0212] O3: 100 sccm

[0213] Pulse sequence:

[0214] Zr precursor: 20 s

[0215] Purge: 5s

[0216] O3: 5 s

[0217] Purge: 5 seconds

[0218] The zirconium precursor is ZrCp(NMe2)3 and can be abbreviated as "ZrCp". The average film thickness is approximately 2 to 20 Å. These films contain approximately 20%–25% Zr, approximately 1%–5% nitrogen, approximately 40%–60% oxygen, and approximately 12%–30% C. The refractive index is 1.92 (at 75°C) to 2.15 (at 150°C) (compared to 2.21 for ZrO2).

[0219] Electrochemical characterization:

[0220] - Cathode material LNMO

[0221] - ZrOC deposited on electrodes via CVD using the following parameters: process temperature = 50°C to 150°C; duration: 5-50 cycles.

[0222] - Electrolyte: 1M LiPF6 in EC: EMC (1:1 wt)

[0223] - Li metal is used as an anode

[0224] - Approximately 5 mg / cm 2 Load capacity, 40 μm thickness

[0225] like Figure 14 and Figure 15 As shown, compared to the original NMC622 electrode, the ZrOC film-coated LNMO electrode exhibits a slight decrease in initial capacity at 0.2C with increasing ALD temperature due to the dense ALD coating. For subsequent cycling, the ZrOC film-coated LNMO electrode demonstrates significantly better cycling performance, particularly ZrCp / O3 at 125C for 20 cycles and ZrCp / O3 at 150C for 20 cycles, maintaining 97% and 100% capacity retention, respectively, after 80 cell cycles at 1C, compared to 82% capacity retention observed for the original LNMO electrode. Compared to the original NMC622 electrode, the LNMO electrode with the ZrOC film exhibits higher capacity up to 5C at low and medium C rates. Figure 16 and Figure 17 Meanwhile, no significant capacity was observed in either the original or ZrOC-coated LNMO electrodes.

[0226] While the invention has been described in conjunction with specific embodiments thereof, it will be apparent to those skilled in the art, in light of the foregoing description, that many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, it is intended to encompass all such alternatives, modifications, and variations falling within the spirit and broad scope of the appended claims. The invention may suitably include, consist of, or consist substantially of the disclosed elements, and may be practiced without any undisclosed elements. Furthermore, any language relating to sequence, such as "first" and "second," should be understood in an exemplary sense rather than a restrictive one. For example, those skilled in the art will recognize that certain steps may be combined into a single step.

[0227] The singular forms “a / an” and “the” include plural indicators unless the context clearly indicates otherwise.

[0228] The term "comprising" in the claims is an open-ended transitional term that means the subsequently defined claim elements are a non-exclusive list, i.e., anything else may be additionally included and remain within the scope of "comprising". "Comprising" is defined herein as necessary to cover the more restrictive transitional terms "substantially constitutes" and "consistent with"; therefore, "comprising" can be replaced by "substantially constitutes" or "consistent with" and remain within the clearly defined scope of "comprising".

[0229] In the claims, "provide" is defined as supplying, providing, making available, or preparing something. This step can, conversely, be performed by any actor even if not explicitly stated in the claims.

[0230] Optional or alternatively means that the events or circumstances described below may or may not occur. This specification includes instances in which events or circumstances occur and instances in which events or circumstances do not occur.

[0231] In this document, a range may be expressed as from about one specific value and / or to about another specific value. When such a range is expressed, it should be understood that another embodiment is from said one specific value and / or to said other specific value, together with all combinations within the range.

[0232] All references identified herein are hereby cited in their entirety and incorporated herein by reference; similarly, specific information for each citation is provided.

Claims

1. A cathode or cathode active material, comprising at least a surface coating of a doped metal oxide film, wherein the doped metal oxide film has an average atomic composition of M. x O y D z , wherein M is selected from niobium or zirconium and combinations thereof, O is oxygen, and D is a dopant atom selected from C or P, and wherein x = 10% to 60%, y ranges from 10% to 60%, and z ranges from 10% to 30%.

2. The cathode or cathode active material as described in claim 1, wherein, The doped metal oxide film is a doped niobium oxide film.

3. The cathode or cathode active material as described in claim 1, wherein, The cathode or cathode active material is only partially coated with the doped metal oxide film.

4. The cathode or cathode active material as described in claim 2, wherein, The cathode or cathode active material is only partially coated with the doped metal oxide film.

5. The cathode or cathode active material according to any one of claims 1-4, wherein, The doped metal oxide film has an average thickness of 0.02 nm to 10 nm.

6. The cathode or cathode active material according to any one of claims 1-4, wherein, The doped metal oxide film has an average thickness of 0.1 nm to 5 nm.

7. The cathode or cathode active material according to any one of claims 1-4, wherein, The doped metal oxide film has an average thickness of 0.2 to 2 nm.

8. The cathode or cathode active material as described in claim 1 or 2, wherein, The doped metal oxide film has an atomic percentage of 15% to 25% carbon atoms.

9. The cathode or cathode active material according to any one of claims 2-4, wherein, The doped metal oxide film has a refractive index of 1.5 to 2.

5.

10. The cathode or cathode active material according to any one of claims 2-4, wherein, The doped metal oxide film has a refractive index of 1.6 to 2.

1.

11. The cathode or cathode active material according to any one of claims 2-4, wherein, The doped metal oxide film has a refractive index of 1.7 to 2.

0.

12. A proton exchange membrane battery comprising a cathode or cathode active material as described in any one of claims 1-11.

13. A method for coating a cathode or cathode active material with a doped metal oxide film, wherein the doped metal oxide film has an average atomic composition of M. x O y D z Where M is selected from niobium or zirconium and combinations thereof, O is oxygen, and D is a dopant atom selected from C or P, and where x = 10% to 60%, y ranges from 10% to 60%, and z ranges from 10% to 30%, the method includes the following steps: a1. Exposing the cathode or cathode active material to chemical precursor vapor, and b1. Deposit the doped metal oxide film onto the cathode or cathode active material.

14. The method of claim 13, further comprising step a2 of exposing the cathode or cathode active material to the co-reactant.

15. The method of claim 14, wherein, Step a1, in which the cathode or cathode active material is exposed to chemical precursor vapor, is performed sequentially with step a2, in which the cathode or cathode active material is exposed to co-reactant.

16. The method of claim 15, further comprising step a1i of purging the chemical precursor vapor prior to step a2 of exposing the cathode or cathode active material to the co-reactant.

17. The method of claim 16, wherein, Step b1, which involves depositing the doped metal oxide film onto the cathode or cathode active material, includes an atomic layer deposition step.

18. The method of claim 16, wherein, Step b1, which involves depositing the doped metal oxide film onto the cathode or cathode active material, includes a chemical vapor deposition step.

19. The method according to any one of claims 14-18, wherein, The co-reactants are an oxygen source, an oxygen-containing silicon precursor, an oxygen-containing tin precursor, a phosphate ester, or a sulfate ester.

20. The method of claim 19, wherein, The oxygen source is O2, O3, H2O, H2O2, NO, NO2, or N2O.

21. The method of claim 19, wherein, The phosphate ester is trimethyl phosphate or diethyl aminophosphate.

22. The method according to any one of claims 13-18, wherein, Repeat one or more of these steps.

23. The method according to any one of claims 13-18, wherein, The temperature of the chemical precursor vapor and / or the cathode or cathode active material is 200°C or lower.

24. The method according to any one of claims 13-18, wherein, The temperature of the chemical precursor vapor and / or the cathode or cathode active material is between 50°C and 200°C.

25. The method according to any one of claims 13-18, wherein, The temperature of the chemical precursor vapor and / or the cathode or cathode active material is 100°C to 150°C.

26. The method according to any one of claims 13-18, wherein, The cathode active material, or the cathode active material in the cathode, is selected from the group consisting of: a) layered oxides; b) spinel cathode materials; c) olivine cathode materials; and combinations thereof.

27. The method of claim 26, wherein, The layered oxide is either lithium nickel manganese cobalt oxide or lithium nickel cobalt aluminum oxide.

28. The method of claim 26, wherein, The spinel cathode material is lithium manganese oxide or lithium nickel manganese oxide.

29. The method of claim 26, wherein, The cathode material of this olivine structure belongs to the olivine phosphate family.

30. The method of claim 26, wherein, The cathode material for this olivine structure is either lithium cobalt phosphate or lithium nickel phosphate.

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