Method for forming metal oxide thin film for electrode mesophase control

Abstract

The present invention provides a novel solution to form an artificial intermediate phase on the electrode by depositing a metal oxide layer by ALD or CVD to protect it from a rapid degradation of its electrochemical properties. The metals considered here are the IVA-VIA elements (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W). The film must be thin, possibly discontinuous, and sufficiently lithium ion conductive, so that the addition of this thin film interface allows a fast lithium ion transfer at the electrode-electrolyte interface.

Description

Background Art

[0001] The formation of the solid electrolyte interface (SEI) on the anode and / or cathode during the first cycle of a lithium-ion battery is observed from the decomposition of the electrolyte at the electrolyte / electrode interface. The decrease in the initial capacity of a lithium-ion battery occurs as a result of the consumption of lithium during the formation of this SEI. Furthermore, the formed SEI layer is non-uniform and unstable, and is not efficient in passivating the electrode surface against the degradation of the electrode active material due to the continuous decomposition of the electrolyte. The SEI layer may undergo physical cracking during the battery cycle, and lithium dendrites may form, leading to a short circuit and subsequent thermal runaway. Furthermore, the SEI layer also creates a barrier potential that further hinders the intercalation of lithium ions within the electrode.

[0002] In current designs, lithium-ion batteries are provided with a (lithium) metal oxide, phosphate, or fluoride coating (e.g., Al x O y 、Li x M y PO z 、M = Nb, Zr, AlTi, etc. or AlM x F yM = W, Y, etc. Lithium-containing thin films are known for their use as surface coating layers of electrode materials in lithium-ion battery applications. Examples of lithium-containing thin films include LiPON, lithium phosphate, lithium borate, lithium borophosphate, lithium niobate, lithium titanate, lithium zirconium oxide, etc. Surface coating of electrodes by ALD / CVD techniques is a preferred means of forming the above-mentioned solid electrolyte interfacial thin films, thus avoiding the formation of these unstable layers. However, deposition of lithium-containing films is difficult to achieve due to the lack of suitable lithium precursors for mass production. Most are not volatile or stable enough, and they may contain undesirable impurities. Another important application of mesophase thin films is in the formation of solid electrolyte materials used in solid-state batteries. Solid-state batteries are solvent-free systems with longer service life, faster charging times, and higher energy densities than conventional lithium-ion batteries. They are considered the next technological step in battery development. ALD / CVD techniques can also be used to obtain uniform and conformal electrode / electrolyte interfacial thin films on complex structures such as 3D batteries.

[0003] Silicon anodes are also within the scope of mesophase thin film applications. Silicon is considered to be the next generation of anodes in the development of lithium-ion batteries, and graphite anodes (Li + / Li) at the same potential level (0.05V + / Li 0.2V) with a graphite anode (372mAhg -1 ) with a higher specific capacity (3600mAhg -1 The main drawback of silicon anodes is their volume expansion of up to 300% during charge / discharge, leading to SEI destabilization and physical cracking of the electrode.

[0004] The use of the intermediate phase thin film can be extended to lithium metal anode technology. Since lithium metal anodes can provide at least three times the theoretical capacity compared to LIBs, they are considered post-lithium ion batteries (LIBs). In addition, lithium metal has attracted attention due to its high capacity (ten times that of graphite), reduced battery volume, and simplicity of the process. However, an uncontrolled lithium metal surface can lead to the growth of Li dendrites, which can cause short circuits and ultimately fires.

[0005] 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, high-Ni cathode materials such as NMC (lithium nickel manganese cobalt oxide) and NCA (lithium nickel cobalt aluminum oxide) are the most promising current candidates for practical applications. However, high-nickel cathode materials tend to become amorphous when a high voltage is applied. One of the main drawbacks of these metal oxide materials is the continuous dissolution of transition metals, especially nickel, due to the parasitic reaction between the cathode material and the electrolyte. This leads to the structural degradation of the cathode active material along with the evolution of gas (O2) at the electrode / electrolyte interface during battery charging. Furthermore, the dissolved nickel ions migrate to the anode side, and their deposition on the anode surface causes rapid decomposition of the SEI at the anode, ultimately leading to battery failure.

[0006] Spinel cathode materials have been thoroughly investigated for their high rate capabilities and low or zero cobalt content. One of the main problems regarding spinel cathode materials such as LMO (lithium manganese oxide) and LNMO (lithium nickel manganese oxide) is the dissolution of divalent manganese ions during the battery charging process (2Mn 3+ →Mn 4+ +Mn 2+ ), which mainly occurs at the electrode / electrolyte interface and then redeposition occurs on the anode, causing the destruction of its SEI in the same mechanism as that of high-Ni cathode materials.

[0007] To address interface issues between the electrolyte and the cathode electrode, such as dissolution of transition metals and decomposition of excessive electrolytes, deposition of thin films on the cathode and / or cathode material can be used. For example, U.S. Patent No. 8,535,832 B2 discloses a 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) on a cathode active material containing Ni, Mn, and Co. U.S. Patent No. 9,543,581 B2 discloses a dry coating of amorphous Al2O3 on precursor particles of a cathode active material containing Ni, Mn, and Co elements. U.S. Patent No. 9,614,224 B2 describes a sputtering method used to deposit a coating on a cathode active material containing Mn. U.S. Patent No. 9,837,665 B2 describes a lithium phosphate oxynitride (LiPON) thin film coating using a sputtering method on a cathode active material containing a Li, Mn, Ni, and oxygen-containing compound having at least one dopant of Ti, Fe, Ni, V, Cr, Cu, and Co. U.S. Patent No. 9,196,901 B2 describes an Al2O3 thin film coating using an atomic layer deposition (ALD) method on a cathode laminate and a cathode active material containing Co, Mn, V, Fe, Si, or Sn and being an oxide, phosphate, silicate, or a mixture of two or more thereof. U.S. Patent No. 10,224,540 B2 describes an Al2O3 thin film coating using an ALD method on a porous silicon anode. U.S. Patent No. 10,177,365 B2 describes an AlWF or AlWFC thin film coating using ALD on a cathode active material containing LiCoO2. U.S. Patent No. 9,531,004 B2 discloses lithium titanate Li x PO y Mn z coating is described. U.S. Patent No. 9,837,665 B2 describes a lithium phosphate oxynitride (LiPON) thin film coating using a sputtering method on a cathode active material containing a Li, Mn, Ni, and oxygen-containing compound having at least one dopant of Ti, Fe, Ni, V, Cr, Cu, and Co. U.S. Patent No. 9,196,901 B2 describes an Al2O3 thin film coating using an atomic layer deposition (ALD) method on a cathode laminate and a cathode active material containing Co, Mn, V, Fe, Si, or Sn and being an oxide, phosphate, silicate, or a mixture of two or more thereof. U.S. Patent No. 10,224,540 B2 describes an Al2O3 thin film coating using an ALD method on a porous silicon anode. U.S. Patent No. 10,177,365 B2 describes an AlWF or AlWFC thin film coating using ALD on a cathode active material containing LiCoO2. U.S. Patent No. 9,531,004 B2 discloses lithium titanate Li x F y or AlW x F y C z thin film coating is described. U.S. Patent No. 9,531,004 B2 discloses lithium titanate Li (4+x) Ti5O 12On an anode material group consisting of (0≦x≦3)(LTO), graphite, silicon, silicon-containing alloy, tin-containing alloy, and combinations thereof, a hybrid thin film coating is described that uses the ALD method and includes a first layer of Al2O3, TiO2, SnO2, V2O5, HfO2, ZrO2, ZnO and a second layer of fluoride-based coating, carbide-based coating, and nitride-based coating.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEM

[0008] The present invention provides the following solution by forming an artificial interphase on an electrode by depositing a metal oxide layer on a cathode or a cathode active material by ALD or CVD to protect it from a rapid decline in electrochemical properties. These metal oxide layers reduce the excessive decomposition of the electrolyte at the electrode / electrolyte interface during SEI formation and reduce the capacity loss in the first cycle. Also, the presence of such a metal oxide layer reduces the dissolution of transition metal cations of the cathode active material caused by the parasitic reaction between the electrolyte and the cathode active material, and then reduces its redeposition on the anode. The electrochemical activity of the battery is thereby improved. As described above, other types of films, especially high-purity metal oxides such as Al2O3, have been proposed. However, this type of material acts as an ion insulator and thus does not allow the best electrochemical performance of the resulting cathode and battery.

[0009] The present invention can be further understood in connection with the following non-limiting, exemplary embodiments as described in the list:

[0010] 1. A method of coating a coated cathode or a cathode active material with a metal oxide film, comprising: exposing the cathode or cathode active material to a vapor of a chemical precursor comprising a chemical precursor of the formula M(=NR a )(OR b )2(NR c 2) and an oxygen source as an oxidation co-reactant, where: M is selected from Nb, Ta, or V, Ra is selected from iPr, tBu, t-Am, each Rb is independently selected from Et, iPr, tBu, sBu, SPen, each Rc is independently selected from Et or Me in step a1; and a method comprising step b1 of depositing a metal oxide film on a cathode or a cathode active material.

[0011] 2. The method according to claim 1, wherein step a1 of exposing a cathode or a cathode active material to a vapor of a chemical precursor and step a2 of exposing the cathode or the cathode active material to a co-reactant are sequentially performed.

[0012] 3. The method according to claim 2, further comprising step a1.i of purging the vapor of the chemical precursor before step a2 of exposing the cathode or the cathode active material to the co-reactant.

[0013] 4. The method according to claim 3, wherein step b1 of depositing a metal oxide film on a cathode or a cathode active material includes an atomic layer deposition process.

[0014] 5. The method according to claim 3, wherein step b1 of depositing a metal oxide film on a cathode or a cathode active material includes a chemical vapor deposition process.

[0015] 6. The method according to any one of claims 1 to 5, wherein the co-reactant is O2, O3, H2O, H2O2, NO, NO2, N2O, or NOx; an oxygen-containing silicon precursor, an oxygen-containing tin precursor, a phosphate such as trimethyl phosphate, diethylphosphoramidate, or an oxygen source such as a sulfate.

[0016] 7. The method according to any one of claims 1 to 6, wherein the precursor is of the formula M(=NR a )(OR b )2(NMeEt).

[0017] 8. R bThe method according to any one of Sentences 1 to 7, wherein at least one of them is independently selected from sBu and SPen.

[0018] 9. The precursor is of the formula M(=NR a )(OR b )2(NMeEt), and at least one of R b is independently selected from sBu and SPen. The method according to any one of Sentences 1 to 7.

[0019] 10. The method according to Sentence 8 or 9, wherein both R b are independently selected from sBu and SPen.

[0020] 11. The method according to any one of Sentences 1 to 10, wherein the metal oxide film produced by Step b1 has an average atomic composition of Nb x O y D z , where O is oxygen and D is any other atom, and x = 0.3 to 0.4, y = 0.4 to 0.65, and z = 0.01 to 0.1.

[0021] 12. The method according to any one of Sentences 1 to 11, wherein the temperature of the vapor of the chemical precursor and / or the cathode or the cathode active material is 100°C to 300°C, more preferably 125°C to 275°C, and even more preferably 125°C to 175°C.

[0022] 13. The method according to any one of Sentences 1 to 12, wherein the 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 to 2 nm.

[0023] 14. The cathode active material, or the cathode active material in the cathode, is selected from the group consisting of: a) layered oxides such as high-Ni cathode materials such as NMC (lithium cobalt manganese nickel oxide) and NCA (lithium aluminum cobalt nickel oxide); b) spinel cathode materials such as LMO (lithium manganese oxide), LNMO (lithium manganese nickel oxide); c) olivine-structured cathode materials, particularly olivine phosphates such as LCP (lithium cobalt phosphate), LNP (lithium nickel phosphate), LFP (lithium iron phosphate); and combinations thereof, and is the method according to any one of sentences 1 to 13.

[0024] 15. One or more of steps a1. and b1. are performed 1 to 10 times, preferably 1 to 3 times, more preferably just once, and is the method according to any one of sentences 1 to 14.

[0025] 16. a) The temperature of the vapor of the chemical precursor and / or the cathode or cathode active material is 100°C to 300°C, more preferably 125°C to 275°C; b) the metal oxide film has an average thickness of 0.02 nm to 10 nm, preferably 0.1 nm to 5 nm, most preferably 0.2 to 2 nm; c) the metal oxide film is at least 50% continuous, preferably 95% or more continuous, more preferably 98% or more continuous on the surface of the cathode or cathode active material, and is the method according to sentences 1 to 15.

[0026] For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description in conjunction with the accompanying drawings, in which the same elements are given the same or similar reference numerals.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0028] The present disclosure provides a solution for forming an interphase on an electrode to protect it from a rapid degradation of its electrochemical properties. The electrode interphase is formed on the cathode active material either before or after its introduction into the final cathode. The metal oxide layer is formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a volatile chemical precursor species M(=NR a )(OR b )2(NR c 2). M is selected from Nb, Ta, or V, R a is selected from iPr, tBu, t-Am each R b is independently selected from Et, iPr, tBu, sBu, SPen, each R c is independently selected from Et or Me.

[0029] These volatile chemical precursors are supplied simultaneously, sequentially, and / or by pulses of the vapor phase of the precursors. In this process, this kind of unexpected efficiency is utilized to achieve improved cathode performance after less than 9 ALD deposition cycles, preferably after 3 cycles or less. This relatively small number of required ALD cycles significantly reduces the consumption of metals such as Nb or Ta and the time required to process the cathode or cathode active material.

[0030] As used herein, "metal oxide" and "metal oxide film" mean a transition metal oxide film having one or more additional elements such that the atomic ratio is MxOyDz (where M is the collective part of transition metals, O is oxygen, and D is the collective part of other elements such as aluminum, zinc, tin, carbon, lithium, and phosphorus). Generally, x ranges from 10% to 60%, y ranges from 10% to 60%, and z ranges from undetectable to 10%, preferably from 0% to 5%.

[0031] Preferably, M is a transition metal that forms one or more stable ions having incompletely filled d orbitals. In particular, M is Nb, but may optionally further include one or more of Ti, Zr, Hf, V, Ta, Cr, Mo, or W.

[0032] The metal oxide film is formed by a CVD or ALD method that deposits a metal oxide layer on the cathode active material before, during, or after the intermediate manufacturing process of the final cathode. The metal oxide film can be a continuous film that completely coats the cathode active material, for example, by powder ALD of the powder cathode active material, before being included in the cathode. The film can be discontinuous as a result of the cathode active material being introduced into the cathode under controlled deposition conditions that limit film growth or such that only a portion of its surface is subjected to the CVD or ALD deposition method. Generally, the metal oxide film has an average thickness of 0.125 to 10 nm, for example, 0.125 nm to 1.25 nm, preferably 0.3 nm to 4 nm.

[0033] A metal oxide deposit composed of the following can be deposited on an electrode: ● Layered structured oxides, preferably "NMC" (lithium cobalt manganese nickel oxide, such as NMC811 (Ni:Mn:Co = 8:1:1), even more preferably NMC955 (Ni:Mn:Co = 9:0.5:0.5)), NCA (lithium aluminum cobalt nickel oxide) or LNO (lithium nickel oxide); ● Spinels, preferably LNMO (lithium manganese nickel oxide) or LMO (lithium manganese oxide); ● Olivine (lithium metal phosphate, the metal can be iron, cobalt, manganese); ● In the form of a carbon anode such as graphite, doped or undoped; ● Silicon anodes, ● Silicon-carbon anodes, ● Tin anodes, ● Silicon-tin anodes, or ● Lithium metal.

[0034] The deposition can be carried out on the electrode active material powder, on the electrode active material porous material, on the electrode active material of different shapes, or can be carried out in a pre-formed electrode in which the electrode active material has already been mixed with conductive carbon and / or a binder and has already been supported by a current collector foil.

[0035] The "cathode" in a lithium-ion battery means the anode in an electrochemical cell (battery) in which the reduction of the cathode material is carried out by the insertion of electrons and lithium ions during charging. During discharge, the cathode material is oxidized by releasing electrons and lithium ions. While the electrons move through the external circuit, the lithium ions move from the cathode to the anode in the electrochemical cell through the electrolyte, or vice versa. The cathode generally consists of a cathode active material (i.e., a lithiated metal layered oxide) and a conductive carbon black agent (acetylene black Super C65, Super P) and a binder (PVDF, CMC).

[0036] The "cathode active material" is the main element in the composition of the cathode (positive electrode) for a battery cell. The cathode active material is, for example, cobalt, nickel, and manganese within a crystal structure such as a layered structure, forming a multi-metal oxide material into which lithium is inserted. Examples of cathode active materials are layered cobalt manganese nickel lithium oxide (LiNixMnyCozO2), spinel manganese lithium oxide (LMn2O4), and olivine lithium iron phosphate (LiFePO4).

[0037] "Continuity" related to the coating on the surface means the percentage value of that surface having a coating material of any thickness. Continuity is generally optically evaluated by imaging the coated material, for example, by grid mapping of the surface, and quantifying the ratio of the surface covered or not covered by the film (in units such as nm 2 ). Electron microscopy can be used to image the surface. The coating amount can be expressed as a percentage of the substrate surface area. Pinholes, voids, or other discontinuities in the film mean that the continuity is less than 100%.

[0038] The metal oxide film is formed by a CVD or ALD method using the vapor of a volatile chemical precursor species M(=NR a )(OR b )2(NR c 2) and one or more other chemical precursors that may contribute to the final film formation. Any additional suitable precursors can be selected for use based on their known applicability to the formation of metal oxides used in other applications.

[0039] Under optimized deposition conditions, preferably Nau2, a wide variety of optional precursors can be used to form the metal oxide.

[0040] Preferred Group IVA metal precursors are as follows: ● M(OR)4, where each R is independently a C1 - C6 carbon chain (linear or branched), most preferably M(OMe)4, M(OiPr)4, M(OtBu)4, M(OsBu)4 ● M(NR 1 R 2 )4, where each R 1 and R 2 are independently a C1 - C6 carbon chain (linear or branched), most preferably M(NMe2)4, M(NMeEt)4, M(NEt2)4 ● 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 are independently a C1 - C6 carbon chain (linear or branched), most preferably MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, 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 ● ML(OR)3, where L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, and each R is independently a C1 - C6 carbon chain (linear or branched), most preferably MCp(OiPr)3, M(MeCp)(OiPr)3, M(EtCp)(OEt)3, MCp*(OEt)3, M(iPrCp)(NMe2)3, M(sBuCp)(NMe2)3, M(tBuCp)(NMe2)3, N(secPenCp)(NMe,)3, M(nPrCp)(NMe2)3

[0041] Preferred VA metal precursors are as follows: ● M(OR)5, each R is independently a C1-C6 carbon chain (linear or branched), most preferably M(OEt)5, M(OiPr)5, M(OtBu)5, M(OsBu)5 ● M(NR 1 R 2 )5, each R 1 and R 2 is independently a C1-C6 carbon chain (linear or branched), most preferably M(NMe2)5, M(NMeEt)5, M(NEt2)5 ● ML(NR 1 R 2 ) x , x = 3 or 4, L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl or an imide in the form of N-R, each R 1 and R 2 is independently a C1-C6 carbon chain (linear or branched), most preferably MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, MCp*(NMe2)3M(=NtBu)(NMe2)3, M(=NtAm)(NMe2)3, M(=NtBu)(NEt2)3, M(=NtBu)(NEtMe)3, M(=NiPr)(NEtMe)3. ● M(=NR 1 )L(NR 2 R 3 ) x , x = 1 or 2, L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, each R 1 and R 2 and R 3 is independently a C1-C6 carbon chain, most preferably MCp(=NtBu)(NMe2)2, M(MeCp)(N=tBu)(NMe2)2, M(EtCp)(N=tBu)(NMe2)2, MCp*(=NtBu)(NMe2)2, MCp(=NtBu)(NEtMe)2, M(MeCp)(N=tBu)(NEtMe)2, M(EtCp)(N=tBu)(NEtMe)2. ● ML(OR) xx = 3 or 4, and L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl or an imide in the form of N-R, each R is independently a C1-C6 carbon chain (linear or branched), most preferably MCp(OiPr)3, M(MeCp)(OiPr)3, M(EtCp)(OEt)3, MCp*(OEt)3M(=NtBu)(OiPr)3, M(=NtAm)(OiPr)3, ● ML(OR) x (NR 1 R 2 ) y , x and y are independently equal to 1 or 2, and L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl (cylohexadienyl), cycloheptadienyl, cyclooctadienyl or an imide in the form of N-R, each R is independently a C1-C6 carbon chain (linear or branched), most preferably 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(NEtMe), 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)(OiPr)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).

[0042] Preferred Group VIA metal precursors are as follows: ● M(OR)6, each R is independently a C1-C6 carbon chain (linear or branched), most preferably M(OEt)5, M(OiPr)5, M(OtBu)5, M(OsBu)5 ● M(NR 1 R 2 )6, each R 1 and R 2 is independently a C1-C6 carbon chain (linear or branched), most preferably M(NMe2)6, M(NMeEt)6, M(NEt2)6 ● M(NR 1 R 2 ) x L y , x and y are independently equal to 1-4, L represents an unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl or N-R form imide, each R 1 and R 2 is independently a C1-C6 carbon chain (linear or branched), most preferably MCp(NMe2)3, M(MeCp)(NMe2)3, M(EtCp)(NEt2)3, MCp*(NMe2)3, M(=NtBu)2(NMe2)2, M(=NtAm)2(NMe2)2, M(=NtBu)(NEt2)2 ● M(OR) x (NR 1 R 2 ) y L z ML, x, y and z are independently equal to 0-4, L represents an unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl or N-R form imide, each R is independently a C1-C6 carbon chain (linear or branched), most preferably 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, M(=NiPr)2(OiPr)2. ● M(=O)xLy, where x, y, and z are independently equal to 0 to 4, and L represents unsubstituted or substituted allyl, cyclopentadienyl, pentadienyl, hexadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, amide or imide in the form of N-R, and each R is independently a C1-C6 carbon chain (linear 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.

[0043] One member of the volatile chemical precursor species can be used as a single precursor or in combination with one or more other precursors, and in any case (if necessary or desirable), an oxidation co-reactant can be optionally used to form a metal oxide film. Those skilled in the art can select appropriate additional precursors and co-reactants from those known in the art and use them under optimized deposition conditions to "adjust" the composition of the metal oxide to produce a metal oxide film having the desired composition. Typical examples of the various precursor options include the following: ● Oxygen can be derived from an O source such as O2, O3, H2O, H2O2, NO, NO2, N2O, or Nox. ● Oxygen can be derived from a dopant source such as an oxygen-containing silicon precursor, an oxygen-containing tin precursor, a phosphate such as trimethyl phosphate, diethyl phosphoramidate, or a sulfate. ● Nitrogen can be derived from an N source such as N2, NH3, N2H4, a N2H4-containing mixture, an alkylhydrazine, NO, NO2, N2O, or NOx. ● Nitrogen can be derived from a dopant source such as a nitrogen-containing silicon precursor, a nitrogen-containing tin precursor, or a phosphate such as diethyl phosphoramidate. ● Carbon can be derived 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, phosphates such as trimethyl phosphate, diethyl phosphoramidate, or sulfates. ● Silicon can be derived from Si sources such as silane or silicon-containing organometallic precursors. ● Tin can be derived from Sn sources such as stannane or tin-containing organometallic precursors. ● Aluminum can be derived from Al sources such as alanes such as alkylalanes or aluminum-containing organometallic precursors. ● Phosphorus can be derived from. Phosphines such as organophosphines or phosphates such as trimethyl phosphate or diethyl phosphoramidate ● Sulfur can be derived from S sources such as sulfur, S8, H2S, H2S2, SO2, organic sulfites, sulfates, or sulfur-containing organometallic precursors. ● The first row transition metals can be derived from known organometallics or other precursors suitable for use in vapor deposition.

Examples

[0044] Examples 1 - 5: Deposition and Electrochemical Performance of NbO Thin Films Deposited on NMC622 Powder Using Nau2 / H2O at 250 °C Experimental Conditions for Deposition / Film Formation: The number of cycles for NMC622 electrodes or NMC powder is typically limited to 20 ALD cycles, which corresponds to a thickness of about 1.5 - 4 angstroms, which is insufficient to achieve the film composition. Therefore, such characterization was performed on films deposited on blank silicon wafers after 300 ALD cycles using O3. The corresponding growth rates and film compositions by X-ray photoelectron spectroscopy (XPS) are as follows: ● GPC ~2.96 Å. Nb: ~38.7%, O: ~54.8%, C: ~3%, N: ~2%, Si ~1.4% ● The refractive index of these films is 2.38.

[0045] Deposition was carried out on NMC622 powder using a fluidized bed reactor under the following experimental conditions: ALD conditions for ALD Reactor temperature setting: 250℃ Reactor pressure: approximately 40 Torr Number of cycles: 1 / 2 / 3 / 9 cycles Precursors and Gases Nautilus2 canister temperature 100℃ Nautilus2 canister pressure 50 Torr N2 bubbling in Nautilus 2 20 sccm O3 FR 20sccm N2 push / purge approx. 120sccm Pulse sequence Nautilus2(2sccm) 900 seconds Purge 1040 seconds H2O 180 seconds Purge 1040 seconds Input base material 5g of NMC622 powder

[0046] The chemical precursor in these examples is Nb(=NtBu)(NEt2)(O-tBu)2 (“Nau2”).

[0047] Electrochemical characterization: Experimental conditions: Battery Cell Condition: ● Cathode material: NMC622 ○ Approximately 5mg / cm 2 The amount of ○ No calendar processing ● Coating material: Nb2O5 Precursor: Nautilus 2 ○ Co-reactant: O3 or H2O Dep.T=250℃ Powder reactor P<40 Torr ○ Amount of coated powder: 5g ○ Reactor filling: x% ● Membrane: Celgate 2400 ● Neat electrolyte: 1 M LiPF6 in EC:EMC (weight ratio 1:1) ● Anode material: Li metal Measurement conditions: ● Temperature: 26 °C ● 3 preliminary cycles at 0.2 C and then at 1 C ● Voltage: 3.0 - 4.3 V, CC

[0048] As shown in Figure 1, the amount of niobium deposited as niobium oxide increases from 1 ALD cycle to 2 - 3 ALD cycles and increases significantly at 9 ALD cycles. The effects of these niobium oxide depositions are seen in Figures 2 and 3. The battery performance is significantly improved compared to the uncoated control. However, quite unexpectedly, it levels off at 2 - 3 cycles, but the best results are obtained with 1 ALD cycle. With 9 ALD cycles, the performance is further improved compared to the control, but it is not the same as for 1 - 3 cycles. Usually, ALD coating for cathode active materials requires 5 - 20 ALD cycles for optimal effect. Surprisingly, Nau2 enables a low ALD cycle process that requires a much shorter time and a much smaller precursor amount per unit of cathode active material. This significantly reduces the cost for industrial applications.

[0049] ALD using ozone instead of water was used with the same conditions and tests. The ozone results were the same as for water, indicating that low cycle number depositions were not substantially affected by the oxidant used.

[0050] Similar TGA and DTA characteristics were measured for the Ta analogue Ta(=NtBu)(NEt2)(O-tBu)2. Similarly, by deposition in 200 cycles on silicon wafers using O3, results similar to those seen for Nb(=NtBu)(NEt2)(O-tBu)2 were obtained. At 275 °C, the growth rate was 4.69 Å / cycle and the composition was Ta: 32.8%, O: 56.5%, and C: 8.1%. Based on these results, for cathodes or cathode material coatings, it is expected that 1 - 9 cycles of ALD will provide advantages in electrode performance similar to those shown for Nau2 above.

[0051] Although the invention has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that many alternative, modified, and different forms are possible in light of the foregoing description. Accordingly, it is intended to embrace all such alternative, modified, and different forms falling within the spirit and broad scope of the appended claims. The invention preferably may consist of, consist essentially of, or include the disclosed elements and may be practiced in the absence of an element not disclosed. Further, where language referring to order such as first and second is used, it should be understood in a typical sense and not in a limiting sense. For example, it may be recognized by those skilled in the art that certain multiple steps may be combined into a single step.

[0052] The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0053] As used in the claims, "Comprising" is an open transitional term meaning that the elements of the claim that follow are a non-exclusive listing, i.e., other things may also be included and still be within the scope of "comprising". "Comprising" is defined herein as necessarily encompassing the more limiting transitional terms "consisting essentially of" and "consisting of". Thus, "comprising" may be replaced with "consisting essentially of" or "consisting of" and still be within the clearly defined scope of "comprising".

[0054] As used in the claims, "Providing" is defined to mean furnishing, supplying, making available, or preparing something. A step may be performed by any actor if there is no express language to the contrary in the claim.

[0055] Optional or optionally means that the matter or circumstance described thereafter may or may not occur. The description includes both the case where the matter or circumstance occurs and the case where it does not occur.

[0056] Ranges may be expressed herein broadly from one particular value and / or to another particular value. When such a range is expressed, another embodiment is to be understood as including all combinations within the range, from one particular value and / or to another particular value.

[0057] All documents shown in this specification are hereby incorporated by reference in their entirety for this application and for the particular information each is cited for in this specification.

Claims

1. A method for coating a cathode or a cathode active material with a metal oxide film, comprising: The cathode or cathode active material may be formed of a compound having the formula M(=NR ａ ) (OR ｂ ) ２ (NR ｃ ２ a) exposing the resulting mixture to vapors of chemical precursors containing precursors of the formula (I) and a source of oxygen as an oxidizing co-reactant; Step b1. of depositing the metal oxide film on the cathode or the cathode active material, where: M is selected from Nb, Ta, or V, R ａ is selected from iPr, tBu, t-Am, Each R ｂ is independently selected from Et, iPr, tBu, sBu, sPen, Each R ｃ is independently selected from Et or Me, Method.

2. The precursor has the formula M(=NR ａ ) (OR ｂ ) ２ 2. The method of claim 1, wherein the compound is (NMeEt).

3. R ｂ The method according to claim 1, wherein at least one of them is independently selected from sBu and sPen.

4. The precursor has the formula M(=NR ａ ) (OR ｂ ) ２ (NMeEt), and R ｂ 2. The method of claim 1, wherein at least one of is independently selected from sBu, sPen.

5. Both R ｂ The method of claim 3 or 4, wherein is independently selected from sBu, sPen.

6. wherein the precursor is Nb(=NtBu)(NEt ２ )(O-tBu) ２ , Ta(=NtBu)(NEt ２ )(O-tBu) ２ , and mixtures thereof, the method according to claim 1.

7. In step a1., the step of exposing the cathode or the cathode active material to the vapor of a chemical precursor and the step of exposing the cathode or the cathode active material to an oxygen source as an oxidation co-reactant are sequentially performed. The method according to claim 1.

8. The method according to claim 2, further comprising step a1.i of purging the vapor of the chemical precursor before the step of exposing the cathode or the cathode active material to an oxygen source as an oxidation co-reactant.

9. The method according to claim 3, wherein step b1. of depositing the metal oxide film on the cathode or the cathode active material includes an atomic layer deposition process.

10. The method according to claim 3, wherein step b1. of depositing the metal oxide film on the cathode or the cathode active material includes a chemical vapor deposition process.

11. wherein the oxygen source is O ２ , O ３ , H ２ O, H ２ O ２ , NO, NO ２ , N ２ O or NOx; A method according to any one of claims 1 to 4, selected from an oxygen-containing silicon precursor and an oxygen-containing tin precursor.

12. The metal oxide film produced by step b1 has an average atomic composition of Nb ｘ O ｙ D ｚ where O is oxygen and D is any other atom, and x = 0.3 to 0.4, y = 0.4 to 0.65 and z = 0.01 to 0.1, the method according to any one of claims 1 to 4.

13. The method according to any one of claims 1 to 4, wherein the temperature of the vapor of the chemical precursor and / or the cathode or the cathode active material is 100°C to 300°C.

14. The method according to any one of claims 1 to 4, wherein the metal oxide film has an average thickness of 0.02 nm to 10 nm.

15. The method according to any one of claims 1 to 4, wherein the cathode active material, or the cathode active material in the cathode, is selected from the group consisting of a) layered oxide; b) spinel cathode material; c) olivine structured cathode material; and combinations thereof.

16. The method according to any one of claims 1 to 4, wherein one or more of steps a1. and b1. are performed 1 to 10 times.

17. a) The temperature of the vapor of the chemical precursor and / or the cathode or the cathode active material is 100°C to 300°C, b) the metal oxide film has an average thickness of 0.02 nm to 10 nm; c) the metal oxide film is at least 50% continuous on the surface of the cathode or the cathode active material. The method according to claim 16.

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