Electrode materials containing layered sodium metal oxides, electrodes containing them, and their use in electrochemistry

Abstract

The present technology relates to an electrode material comprising an electrochemically active material, the electrochemically active material comprising a P2-type or O3-type layered sodium metal oxide. x MO2, where 0.5≦x≦1.0 and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof. Electrodes, electrochemical cells, and batteries containing the electrode materials are also described. The present technology relates to electrochemical cells containing a negative electrode, a positive electrode, and an electrolyte.

Description

Technical Field

[0001] Related Applications This application claims priority under applicable law to U.S. Provisional Patent Application No. 62 / 740,185, filed Oct. 2, 2018, the entire content of which is incorporated herein by reference for all purposes.

[0002] Technical Field This application relates to the field of electrochemical active materials and their use in electrochemical applications. More particularly, this application generally relates to electrode materials containing layered sodium metal oxides as electrochemical active materials, electrodes containing them, methods for their manufacture, and their use in electrochemical cells.

Background Art

[0003] Background Layered lithium metal oxides of the formula LiMO2 (M = transition metal), such as oxides having a layered structure like lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), are cathode materials commercially used in lithium-ion batteries (LIBs). Layered LiMO2 can be classified by their stacking shape. Different types of stacking have different stacking arrangements of oxide layers that change the arrangement of (MO2) sheets and the shape of the sites occupied by lithium ions. The oxygen environment of lithium ions can be, for example, octahedral (O), prismatic (P), or tetrahedral (T). Layered LiMO2 can also be characterized by the number of MO2 sheets found within the unit cell. The structure of layered LiMO2 has a significant impact on the electrochemical properties of the material, such as its capacity, cyclability, and charge-discharge rate. Layered P2 and O3 type structures, for example, are of interest for use in electrochemical cells.

[0004] One of the main drawbacks of currently used electrode materials containing layered oxides as the electrochemically active material is the high production cost. For example, the rising price of lithium can be a problem for the increasing market share of LIBs. In fact, lithium is used in multiple components of conventional LIBs, such as the positive and negative electrodes as well as the electrolyte. Therefore, supply issues and the cost of lithium are at the center of the main factors affecting their expansion into some commercial renewable energy applications.

[0005] Therefore, there is a need to develop new electrode materials. For example, an electrode material containing P2 and / or O3 type layered oxides as the electrochemically active material, which eliminates one or more of the drawbacks of conventional layered oxide materials.

Summary of the Invention

Means for Solving the Problems

[0006] Overview According to one aspect, the present technology is an electrode material containing an electrochemically active material, wherein the electrochemically active material contains a layered sodium metal oxide of the formula Na x MO2, where 0.5 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof, and relates to an electrode material.

[0007] In one embodiment, the electrochemically active material is - a P2 type layered sodium metal oxide of the formula Na x MO2 (where x is a number such that 0.5 ≦ x ≦ 0.8, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, and combinations thereof), and - an O3 type layered sodium metal oxide of the formula Na x MO2 (where x is a number such that 0.8 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof) selected from layered sodium metal oxides containing.

[0008] In another embodiment, the electrochemically active material comprises a layered sodium metal oxide of the formula Na x M’ 1-y M y O2, where x and M are as defined herein, y is a number such that 0 ≦ y ≦ 1.0, M’ is different from M and is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof.

[0009] In another embodiment, the electrochemically active material comprises a layered sodium metal oxide of the formula Na x M’ 1-y Mn y O2, where x is as defined herein, y is such that 0 ≦ y ≦ 1.0, and M’ is selected from Co, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof.

[0010] In another embodiment, the electrode material further comprises an electronically conductive material selected from carbon black, acetylene black, graphite, graphene, carbon fiber, carbon nanofiber, carbon nanotube, and combinations thereof.

[0011] In another embodiment, the electrode material further comprises a binder selected from the group consisting of polyether-type polymer binders, fluorinated polymers, and water-soluble binders.

[0012] According to another aspect, the present technology relates to an electrode comprising the electrode material as defined herein on a current collector. In one embodiment, the electrode is a positive electrode.

[0013] According to another aspect, the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein the positive electrode is as defined herein. In one embodiment, the negative electrode comprises metallic lithium. Alternatively, the negative electrode comprises metallic sodium.

[0014] In another embodiment, the electrolyte is a liquid electrolyte containing a salt in a solvent. Alternatively, the electrolyte is a gel electrolyte containing a salt and, optionally, a solvated polymer in a solvent. According to another alternative form, the electrolyte is a solid polymer electrolyte containing a salt in a solvated polymer. In one embodiment, the salt is a lithium salt. Alternatively, the salt is a sodium salt.

[0015] According to another aspect, the present technology relates to a battery including at least one electrochemical cell as defined herein. In one embodiment, the battery is selected from a lithium-ion battery and a sodium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

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DETAILED DESCRIPTION OF THE INVENTION

[0035] DETAILED DESCRIPTION The following detailed description and examples are presented for illustrative purposes only and should not be construed as further limiting the scope of the invention.

[0036] All technical and scientific terms and expressions used herein have the same definitions as commonly understood by those skilled in the art related to this technology. However, definitions of some of the terms and expressions used are provided below.

[0037] When the term "about" or its equivalent term "approximately" is used herein, it means in the vicinity or near ~. For example, when the term "about" or "approximately" is used in relation to a numerical value, it modifies it to be up to 10% above and below the nominal value. This term may also take into account, for example, experimental errors or rounding of measuring devices.

[0038] When a range of values is referred to in this application, unless otherwise indicated, the lower and upper limits of the range are always included in the definition.

[0039] This technology relates to the use of layered oxides of sodium and at least one metal element as an electrochemically active material. The layered oxide of sodium and at least one metal element has a P2-type or O3-type stacking.

[0040] In one example, the metal element is a metal, such as a transition metal, a post-transition metal, a metalloid, an alkali metal, an alkaline earth metal, or a combination thereof. For example, the metal is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations of at least two of these.

[0041] In one example, the electrochemically active material comprises a layered sodium metal oxide of the formula Na x MO2, where x is a number such that 0.5 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof.

[0042] In another example, the electrochemically active material comprises a P2-type layered sodium metal oxide of the formula Na x MO2, where x is a number such that 0.5 ≦ x ≦ 0.8, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, and combinations thereof.

[0043] In another example, the electrochemically active material comprises an O3-type layered sodium metal oxide of the formula Na x MO2, where x is a number such that 0.8 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof.

[0044] In another example, the electrochemically active material is a layered sodium cobalt oxide of the formula Na x CoO2, where x is as defined herein. For example, the layered sodium cobalt oxide has a P2-type stacking. Examples of the layered sodium cobalt oxide have the formula Na 0.5 CoO2.

[0045] In another example, the electrochemically active material is a layered sodium manganese oxide of the formula Na x MnO2, where x is as defined herein.

[0046] Further examples of the electrochemically active material include a mixed layered oxide of the formula Na x M’ 1-y M y O2, where x and M are as defined herein, y is a number such that 0 ≦ y ≦ 1.0, M’ is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof, and M is different from M’.

[0047] For example, the electrochemical active material includes a mixed layered oxide of sodium, manganese, and metal of the formula Na x M’ 1-y Mn y O2, where x and y are as defined herein, and M’ is selected from Co, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof. For example, the electrochemical active material has the formula Na x (NiCo) 1-y Mn y O2, Na x Co 1-y Mn y O2, Na x Ni 1-y Mn y O2, and Na x (CoTi) 1-y Mn 1-y O2 (where x and y are as defined). Non-limiting examples of the electrochemical active material include Na 0.5 CoO2, Na 0.67 CoO2, Na 0.67 Co 0.67 Mn 0.33 O2, Na 0.67 Ni 0.33 Mn 0.67 O2, Na 0.67 Co 0.6 Mn 0.4 O2, Na 0.67 Co 0.55 Mn 0.45 O2, Na 0.67 Co 0.5 Mn 0.5 O2, Na 0.67 Co 0.50 Mn 0.33 Ti 0.17 O2, Na 0.6 MnO2, NaNi 0.4 Co 0.2 Mn 0.4 O2, and NaNi 0.33 Fe 0.33 Mn 0.33 O2.

[0048] The electrochemically active material may be doped with other elements or impurities, optionally in small amounts, for example to adjust or optimize its electrochemical properties. In some cases, the electrochemically active material may be doped by partial substitution with other ions of a metal (M). For example, the electrochemically active material may be doped with transition metals (e.g., Fe, Co, Ni, Mn, Ti, Cr, Cu, V) and / or metals other than transition metals (e.g., Mg, Al, Sb).

[0049] The electrochemically active material described herein preferably contains substantially no lithium. For example, the electrochemically active material contains less than 2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.1 wt%, less than 0.05 wt% or less than 0.01 wt% of lithium. Thus, the electrochemically active material can potentially reduce production costs compared to the corresponding P2-type or O3-type lithium metal oxide structures. The electrochemically active material can also retain the same structure as the corresponding P2-type or O3-type lithium metal oxide structure and have similar electrochemical performance.

[0050] The present technology also relates to an electrode material containing the electrochemically active material described herein. In one example, the electrode material described herein may further contain an electronically conductive material. Non-limiting examples of electronically conductive materials include carbon black, Ketjen TM carbon, Super P TM carbon, acetylene black, Shawinigan carbon, Denka TM carbon black, graphite, graphene, carbon fibers (e.g., vapor-grown carbon fibers (VGCF)), carbon nanofibers, carbon nanotubes or combinations of at least two of these. According to one example, the electronically conductive material is Ketjen TM carbon. According to one alternative form, the electronically conductive material is Super P TM carbon. According to another alternative form, the electronically conductive material is VGCF.

[0051] The electrode materials described herein may also further include a binder. For example, the binder is selected for its compatibility with various elements of the electrochemical cell. Any known compatible binder is contemplated. For example, the binder is selected from polyether-type polymer binders, fluorinated polymers, and water-soluble binders (water-soluble). According to one example, the binder is a fluorinated polymer such as polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE). According to another example, the binder is a water-soluble binder such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), hydrogenated NBR (HNBR), epichlorohydrin rubber (CHR), or acrylate rubber (ACM), and optionally includes a thickener such as carboxymethyl cellulose (CMC) or a polymer such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMMA), or a combination thereof. According to one example, the binder is a polyether-type polymer binder. For example, the polyether-type polymer binder is linear, branched, and / or cross-linked, and is based on two combinations such as poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), or (EO / PO copolymer), and optionally includes cross-linkable units. In one variant of the purpose, the binder is PVdF or a polyether-type polymer as defined herein.

[0052] The electrode materials described herein may further optionally include additional components or additives such as inorganic particles, glass or ceramic particles, ion conductors, salts (e.g., lithium salts), and other similar additives.

[0053] The present technology also relates to an electrode comprising the electrode material as defined herein on a current collector (e.g., aluminum, copper). Alternatively, the electrode may be self-supporting. In one variant of the purpose, the electrode is a positive electrode.

[0054] The present technology also relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the positive electrode is as defined herein.

[0055] In one example, the electrochemically active material of the negative electrode or counter electrode may be selected from all known suitable materials. For example, the electrochemically active material of the negative electrode may be selected for its electrochemical compatibility with the electrochemically active material as defined herein. For example, the electrochemically active material of the negative electrode may include an alkali metal film, such as a metal lithium film, a metal sodium film or a film of an alloy containing at least one of these.

[0056] The electrolyte is also selected for its compatibility with the various elements of the electrochemical cell. Any kind of suitable electrolyte is contemplated. According to one example, the electrolyte is a liquid electrolyte containing a salt in a solvent. According to an alternative form, the electrolyte is a gel electrolyte containing a salt and, optionally, a solvated polymer in a solvent. According to another alternative form, the electrolyte is a solid polymer electrolyte containing a salt in a solvated polymer.

[0057] The salt is preferably an ionic salt such as a lithium salt or a sodium salt. Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (LiNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiSO3CF3) (LiTf), lithium fluoroalkyl phosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolate(2-)-O,O’)borate [B(C6O2)2] (LiBBB), and combinations thereof. According to a variant of the first object, the lithium salt is LiPF6. According to a variant of the second object, the lithium salt is LiFSI. According to a variant of the third object, the lithium salt is LiTFSI. Non-limiting examples of sodium salts include those in which the lithium ions in the above salts are replaced by sodium ions.

[0058] The solvent can be a polar aprotic non-aqueous solvent when present in the electrolyte. Non-limiting examples of the solvent include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and vinylene carbonate (VC), acyclic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC), lactones such as γ-butyrolactone (γ-BL) and γ-valerolactone (γ-VL), acyclic ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), ethoxymethoxyethane (EME), trimethoxymethane and ethyl monoglyme, cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane and dioxolane derivatives, and other solvents such as dimethyl sulfoxide, formamide, acetamide, dimethylformamide, acetonitrile, propylnitrile, nitromethane, triester phosphate, sulfolane, methylsulfolane, propylene carbonate derivatives and mixtures thereof.

[0059] Examples of the electrolyte include lithium hexafluorophosphate (LiPF6) dissolved in a non-aqueous solvent mixture such as a mixture of ethylene carbonate and diethyl carbonate (EC / DEC) (3:7 by volume) or a mixture of ethylene carbonate and dimethyl carbonate (EC / DMC) (4:6 by volume).

[0060] When the electrolyte is a gel electrolyte or a polymer gel electrolyte, the gel polymer electrolyte may include, for example, a polymer precursor and a salt (e.g., the salt defined above), a solvent and, if necessary, a polymerization and / or crosslinking initiator. Non-limiting examples of the gel electrolyte include, but are not limited to, the gel electrolytes described in PCT patent applications published as WO2009 / 111860 (Zaghib et al.) and WO2004 / 068610 (Zaghib et al.).

[0061] The electrolyte can also be a solid polymer electrolyte (SPE) that contains a salt in a solvated polymer. Any kind of known compatible SPE is contemplated. For example, the SPE is selected for its compatibility with various elements of the electrochemical cell. For example, the SPE is selected for its compatibility with lithium and / or sodium. The SPE may generally contain a salt and one or more solid polar polymers that are crosslinked as necessary. Polyether-type polymers such as those based on poly(ethylene oxide) (PEO) can also be used, but multiple other compatible polymers for SPE preparation are also known and are similarly contemplated. By way of example, the polymer may be further crosslinked. Examples of such polymers include branched polymers, such as star polymers or comb polymers such as those described in the PCT patent application published as WO2003 / 063287 (Zaghib et al.).

[0062] The gel electrolyte or liquid electrolyte as defined above may also impregnate a separator such as a polymer separator. Non-limiting examples of separators include polyethylene (PE), polypropylene (PP), cellulose, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and polypropylene-polyethylene-polypropylene (PP / PE / PP) membranes. For example, the separator is a commercially available polymer separator of the Celgard TM type.

[0063] The electrolyte may also optionally contain additional components or additives such as ion conductors, inorganic particles, glass or ceramic particles, such as nanoceramics (such as Al2O3, TiO2, SiO2 and other similar compounds), and other similar additives.

[0064] The present technology also relates to a battery generally including at least one electrochemical cell as defined herein. For example, the battery is selected from a lithium battery, a lithium ion battery, a sodium battery, and a sodium ion battery. According to one variant of the object, the battery is a lithium battery or a lithium ion battery.

Example

[0065] The following examples are for illustrative purposes and should not be construed as further limiting the scope of the intended invention. These examples are better understood by referring to the accompanying drawings.

[0066] Example 1 Synthesis of Electrochemical Active Material

[0067] Using solid state reaction technology, the formula Na 0.5 CoO2, Na 0.67 CoO2, Na 0.67 Co 0.67 Mn 0.33 O2, Na 0.67 Ni 0.33 Mn 0.67 O2, Na 0.67 Co 0.6 Mn 0.4 O2, Na 0.67 Co 0.55 Mn 0.45 O2, Na 0.67 Co 0.5 Mn 0.5 O2, Na 0.67 Co 0.50 Mn 0.33 Ti 0.17 O2, Na 0.6 MnO2, NaNi 0.4 Co 0.2 Mn 0.4 O2 and NaNi 0.33 Fe 0.33 Mn 0.33A layered oxide of O2 was prepared. Each precursor (such as Na2CO3 and metal oxides such as Mn2O3, Co2O3, NiO, Fe2O3, and TiO2) was weighed to obtain the desired stoichiometric amount. The sample was prepared by crushing and mixing the precursor powders. Subsequently, the crushed and mixed precursor powders were placed in an oven and heated at 700 °C to 1000 °C for 5 to 24 hours under an air or oxygen atmosphere.

[0068] Example 2 Characterization of the electrochemically active material a) Powder X-ray diffraction (XRD)

[0069] The atomic and molecular structure of the electrochemically active material was examined by X-ray diffraction performed on both the P2-type and O3-type layered sodium metal oxide structures prepared in Example 1. Figure 1 shows the X-ray diffraction pattern of P2-type layered Na 0.5 CoO2 powder, and Figure 2 shows the X-ray diffraction pattern of O3-type layered NaNi 0.4 Co 0.2 Mn 0.4 O2 powder.

[0070] Example 3 Electrochemical properties

[0071] All cells were assembled in a 2032-type coin cell housing with a negative electrode comprising the components indicated in Table 1 and a lithium metal film on an aluminum current collector. Cells containing a liquid electrolyte were assembled using a Celgard TM separator impregnated with a 1 M solution of LiPF6 in an EC / DEC mixture (3:7 by volume) or an EC / DMC mixture (4:6 by volume). Cells containing a solid polymer electrolyte were assembled using an SPE containing LIFSI or LITFSI. Table 1. Cell composition

Table 1

[0072] a) Electrochemical behavior of P2-type Na 0.67 CoO2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 CoO2 material prepared in Example 1.

[0073] Figure 3 shows the charge-discharge profile of Cell 1. The charge-discharge was carried out at 0.1C and recorded against Li / Li + at a temperature of 25 °C. Cell 1 provided a capacity of approximately 104 mAh / g.

[0074] Figure 4 shows the charge-discharge profiles of Cell 1 at various cycle rates. The charge-discharge was carried out at 0.1C, 0.2C, 0.5C, 1C, 2C, and 4C and recorded against Li / Li + at a temperature of 25 °C. At a cycle rate of 4C, Cell 1 provided a capacity of approximately 92 mAh / g, effectively showing a capacity retention of 87% at increasing cycle rates from 0.5C to 4C.

[0075] Figure 5 shows a graph representing the capacity (mAh / g) as a function of the number of cycles of Cell 1. A long-cycle experiment was performed at a constant charge / discharge current of 1C. The results were recorded against Li / Li + at a temperature of 25 °C. Figure 5 shows a capacity retention of approximately 97% after 200 cycles.

[0076] The influence of the binder selection and cycle temperature is demonstrated in Figures 6 and 7.

[0077] Figure 6 shows the charge-discharge profile of Cell 2. The charge-discharge was carried out at 0.3C between 2.0 and 4.4 V against Li / Li + at a temperature of 50 °C. Cell 2 provided a capacity of approximately 107 mAh / g.

[0078] Figure 7 shows the charge-discharge profile of Cell 2. The charge-discharge was carried out at 0.3C between 2.0 and 4.4 V against Li / Li + at a temperature of 80 °C. Cell 2 provided a capacity of approximately 107 mAh / g.

[0079] b) P2-type Na 0.67Co 0.67 Mn 0.33 Electrochemical behavior of O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Co 0.67 Mn 0.33 O2 material prepared in Example 1.

[0080] Figure 8 shows the charge-discharge profile of Cell 3. Charge-discharge was carried out at 0.1C and at a temperature of 25 °C between 2.0 and 4.4 V with respect to Li / Li + Cell 3 provided a capacity of approximately 150 mAh / g.

[0081] Figure 9 shows the charge-discharge profiles of Cell 3 at various cycle rates. Charge-discharge was carried out at 0.1C, 0.2C, 0.5C, 1C, 2C, and 4C and recorded at a temperature of 25 °C with respect to Li / Li + At a cycle rate of 4C, Cell 3 provided a capacity of approximately 121 mAh / g, effectively showing 80% capacity retention at increasing cycle rates from 0.1C to 4C.

[0082] Figure 10 shows a graph representing the capacity (mAh / g) as a function of the number of cycles of Cell 3. A long-cycle experiment was performed at a constant charge / discharge current of 2C. The results were recorded at a temperature of 25 °C with respect to Li / Li + Figure 10 shows a capacity retention of approximately 93.4% after 100 cycles.

[0083] c) Electrochemical behavior of P2-type Na 0.67 Ni 0.33 Mn 0.67 O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Ni 0.33 Mn 0.67 O2 material prepared in Example 1.

[0084] Figure 11 shows the initial charge-discharge curve of Cell 4. Charge-discharge was carried out at 0.1C and at a temperature of 25 °C with respect to Li / Li +It was carried out between 2.0 and 4.4 V. Cell 4 provided a capacity of approximately 182 mAh / g.

[0085] Figure 12 shows the charge-discharge profiles of Cell 5, namely the first cycle and the fifth cycle. The charge-discharge was carried out at 0.3C and at a temperature of 80 °C with Li / Li + It was carried out between 2.0 and 4.0 V. Cell 5 provided a capacity of approximately 120 mAh / g.

[0086] d) Electrochemical behavior of P2-type Na 0.67 Co 0.6 Mn 0.4 O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Co 0.6 Mn 0.4 O2 material prepared in Example 1.

[0087] Figure 13 shows the charge-discharge profile of Cell 6. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C with Li / Li + It was carried out between 2.0 and 4.4 V. Cell 6 provided a capacity of approximately 142 mAh / g.

[0088] e) Electrochemical behavior of P2-type Na 0.67 Co 0.55 Mn 0.45 O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Co 0.55 Mn 0.45 O2 material prepared in Example 1.

[0089] Figure 14 shows the charge-discharge profile of Cell 7. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C with Li / Li + It was carried out between 2.0 and 4.4 V. Cell 7 provided a capacity of approximately 110 mAh / g.

[0090] f) Electrochemical behavior of P2-type Na 0.67 Co 0.5 Mn 0.5 O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Co 0.5 Mn 0.5 O2 material prepared in Example 1.

[0091] Figure 15 shows the charge-discharge profile of Cell 8. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C between 2.0 and 4.4 V with respect to Li / Li + Cell 8 provided a capacity of approximately 114 mAh / g.

[0092] g) Electrochemical behavior of P2-type Na 0.67 Co 0.50 Mn 0.33 Ti 0.17 O2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.67 Co 0.50 Mn 0.33 Ti 0.17 O2 material prepared in Example 1.

[0093] Figure 16 shows the charge-discharge profile of Cell 9. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C between 2.0 and 4.5 V with respect to Li / Li + Cell 9 provided a capacity of approximately 137 mAh / g.

[0094] h) Electrochemical behavior of P2-type Na 0.60 MnO2 This example illustrates the electrochemical behavior of the P2-type layered Na 0.60 MnO2 material prepared in Example 1.

[0095] Figure 17 shows the charge-discharge profile of Cell 10. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C between 2.0 and 4.4 V with respect to Li / Li + Cell 10 provided a capacity of approximately 73 mAh / g.

[0096] i) Electrochemical behavior of O3-type NaNi 0.4 Co 0.2 Mn 0.4 O2 This example illustrates the electrochemical behavior of the O3-type layered NaNi 0.4 Co 0.2 Mn 0.4 O2 material.

[0097] Figure 18 shows the charge-discharge profile of cell 11. The charge-discharge was carried out at 0.1C and at a temperature of 25 °C between 2.0 and 4.4 V with respect to Li / Li + Cell 11 provided a capacity of approximately 118 mAh / g.

[0098] Figure 19 shows a graph representing the capacity (mAh / g) as a function of the number of cycles of cell 11. The long-cycle experiment was carried out at a constant charge / discharge current of 0.1C. The results were recorded at a temperature of 25 °C with respect to Li / Li + Figure 19 shows good capacity retention after 50 cycles.

[0099] Numerous modifications can be made to any of the above embodiments without departing from the intended scope of the present invention. The reference documents, patents or scientific literature documents referred to in this application are hereby incorporated by reference in their entirety for all purposes. The present invention provides, for example, the following items. (Item 1) An electrode material containing an electrochemically active material, wherein the electrochemically active material contains a layered sodium metal oxide of the formula Na x MO 2 , where x is a number such that 0.5 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof. (Item 2) The electrochemically active material is - a P2-type layered sodium metal oxide of the formula Na x MO 2 (where x is a number such that 0.5 ≦ x ≦ 0.8, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, and combinations thereof), and - an O3-type layered sodium metal oxide of the formula Na x MO 2 (where x is a number such that 0.8 ≦ x ≦ 1.0, and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof), The electrode material according to Item 1, comprising a layered sodium metal oxide selected from the above. (Item 3) The electrochemically active material contains a layered sodium metal oxide of the formula Na x M’ 1-y M y O2 , where x and M are as described in Item 1 or 2, y is a number such that 0 ≦ y ≦ 1.0, M' is different from M, and M' is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof. (Item 4) The electrochemically active material contains a layered sodium metal oxide of the formula Na x M’ 1-y Mn y O 2 , where x is as described in Item 1 or 2, y is a number such that 0 ≦ y ≦ 1.0, and M' is selected from Co, Fe, Ni, Ti, Cr, V, Cu, Sb, and combinations thereof. (Item 5) The electrochemically active material contains a layered sodium cobalt oxide of the formula Na x CoO 2 , where x is as described in Item 1 or 2. (Item 6) The electrochemically active material contains a layered sodium manganate of the formula Na x MnO 2 , where x is as described in Item 1 or 2. (Item 7) The electrochemically active material contains a layered sodium metal oxide of the formula Na x (NiCo) 1-y Mn y O 2 The electrode material according to any one of items 1 to 4, comprising a layered sodium metal oxide, wherein x is as described in item 1 or 2, and y is as described in item 4. (Item 8) The electrochemically active material is of the formula Na x Co 1-y Mn y O 2 The electrode material according to any one of items 1 to 4, comprising a layered sodium metal oxide, wherein x is as described in item 1 or 2, and y is as described in item 4. (Item 9) The electrochemically active material is of the formula Na x Ni 1-y Mn y O 2 The electrode material according to any one of items 1 to 4, comprising a layered sodium metal oxide, wherein x is as described in item 1 or 2, and y is as described in item 4. (Item 10) The electrochemically active material is of the formula Na x (CoTi) 1-y Mn 1-y O 2 The electrode material according to any one of items 1 to 4, comprising a layered sodium metal oxide, wherein x is as described in item 1 or 2, and y is as described in item 4. (Item 11) The electrode material according to any one of items 1 to 10, further comprising an electron conductive material. (Item 12) The electrode material according to item 11, wherein the electron conductive material is selected from carbon black, acetylene black, graphite, graphene, carbon fiber, carbon nanofiber, carbon nanotube, and combinations thereof. (Item 13) The electrode material according to item 12, wherein the electron conductive material comprises carbon fiber. (Item 14) The electrode material according to item 13, wherein the carbon fiber is vapor grown carbon fiber (VGCF). (Item 15) The electrode material according to item 12, wherein the electron conductive material comprises carbon black. (Item 16) The electrode material according to item 15, wherein the carbon black is Super P TM carbon. (Item 17) The electrode material according to item 15, wherein the carbon black is Ketjen TM carbon. (Item 18) The electrode material according to any one of items 1 to 17, further comprising a binder. (Item 19) The electrode material according to item 18, wherein the binder is selected from the group consisting of polyether-type polymer binders, fluorinated polymers, and water-soluble binders. (Item 20) The electrode material according to item 19, wherein the binder is a fluorinated polymer. (Item 21) The electrode material according to item 20, wherein the fluorinated polymer is polyvinylidene fluoride (PVdF). (Item 22) The electrode material according to item 20, wherein the fluorinated polymer is polytetrafluoroethylene (PTFE). (Item 23) The electrode material according to item 19, wherein the binder is a polyether-type polymer binder. (Item 24) The electrode material according to item 23, wherein the polyether-type polymer binder is branched and / or crosslinked. (Item 25) The electrode material according to item 23 or 24, wherein the polyether-type polymer binder is based on polyethylene oxide (PEO). (Item 26) An electrode comprising the electrode material according to any one of items 1 to 25 on a current collector. (Item 27) The electrode according to item 26, wherein the electrode is a positive electrode. (Item 28) An electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein the positive electrode is as described in item 26 or 27. (Item 29) The electrochemical cell according to item 28, wherein the negative electrode contains metallic lithium. (Item 30) The electrochemical cell according to item 28, wherein the negative electrode contains metallic sodium. (Item 31) The electrochemical cell according to any one of items 28 to 30, wherein the electrolyte is a liquid electrolyte containing a salt in a solvent. (Item 32) The electrochemical cell according to any one of items 28 to 30, wherein the electrolyte is a gel electrolyte containing a salt and, optionally, a solvated polymer in a solvent. (Item 33) The electrochemical cell according to any one of items 28 to 30, wherein the electrolyte is a solid polymer electrolyte containing a salt in a solvated polymer. (Item 34) The electrochemical cell according to any one of items 31 to 33, wherein the salt is a lithium salt. (Item 35) The electrochemical cell according to any one of items 31 to 33, wherein the salt is a sodium salt. (Item 36) A battery comprising at least one electrochemical cell according to any one of items 28 to 35. (Item 37) The battery according to item 36, wherein the battery is selected from a lithium-ion battery and a sodium-ion battery. (Item 38) The battery according to item 36 or 37, wherein the battery is a lithium-ion battery. (Item 39) The battery according to item 36 or 37, wherein the battery is a sodium-ion battery.

Claims

1. An electrochemical cell comprising a negative electrode, a positive electrode, and an electrolyte, wherein the positive electrode comprises an electrode material containing an electrochemically active material, and the electrochemically active material is a P2-type or O3-type layered sodium metal oxide selected from Na₀.₅CoO₂, Na₀.₆₇CoO₂, Na₀.₆₇Co₀.₆₇Mn₀.₃₃O₂, Na₀.₆₇Ni₀.₃₃Mn₀.₆₇O₂, Na₀.₆₇Co₀.₆Mn₀.₄O₂, Na₀.₆₇Co₀.₅₅Mn₀.₄₅O₂, Na₀.₆₇Co₀.₅₀Mn₀.₃₃Ti₀.₁₇O₂, Na₀.₆MnO₂, NaNi₀.₄Co₀.₂Mn₀.₄O₂, and NaNi₀.₃₃Fe₀.₃₃Mn₀.₃₃O₂, and the negative electrode contains metallic lithium,[[]] An electrochemical cell.[[]]

2. wherein the electrochemically active material is Na ０．５ CoO ２ The electrochemical cell according to claim 1.

3. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇CoO₂.[[]]

4. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇Co₀.₆₇Mn₀.₃₃O₂.[[]]

5. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇Ni₀.₃₃Mn₀.₆₇O₂.[[]]

6. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇Co₀.₆Mn₀.₄O₂.[[]]

7. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇Co₀.₅₅Mn₀.₄₅O₂.[[]]

8. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆₇Co₀.₅₀Mn₀.₃₃Ti₀.₁₇O₂.[[]]

9. The electrochemical cell according to claim 1, wherein the electrochemically active material is Na₀.₆MnO₂.[[]]

10. The electrochemical cell according to claim 1, wherein the electrochemically active material is NaNi₀.₄Co₀.₂Mn₀.₄O₂.[[]]

11. The electrochemical cell according to claim 1, wherein the electrochemically active material is NaNi₀.₃₃Fe₀.₃₃Mn₀.₃₃O₂.[[]]

12. An electronic conductive material, and / or A binder The electrochemical cell according to any one of claims 1 to 11, further comprising

13. The electrochemical cell according to claim 12, wherein the electronically conductive material is selected from carbon black, acetylene black, graphite, graphene, carbon fiber, carbon nanofiber, carbon nanotube, and combinations thereof.

14. The electrochemical cell according to claim 12 or 13, wherein the binder is selected from the group consisting of polyether-type polymer binders, fluorinated polymers, and water-soluble binders.

15. The electrochemical cell according to any one of claims 1 to 14, wherein the electrode material of the positive electrode is on a current collector.

16. The electrochemical cell according to any one of claims 1 to 15, wherein the electrolyte is a liquid electrolyte containing a salt in a solvent, or a gel electrolyte containing a salt and, optionally, a solvated polymer in a solvent, or a solid polymer electrolyte containing a salt in a solvated polymer.

17. A battery comprising at least one electrochemical cell according to any one of claims 1 to 16.

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