Coated particulate material for use in electrodes of electrochemical cells - Patents.com

Abstract

Coated particulate material for use in electrodes of electrochemical cells, and methods for making the coated particulate material, electrodes comprising the coated particulate material for use in electrochemical cells, electrochemical cells comprising the coated particulate material, and methods for using the coated particulate material to make electrodes for use in electrochemical cells are described.

Description

[Technical field]

[0001] Coated particulate material for use in electrodes of electrochemical cells, methods of preparing the coated particulate material, electrodes comprising the coated particulate material, electrochemical cells comprising the coated particulate material, and methods of using the coated particulate material to prepare electrodes for use in electrochemical cells are described. [Background technology]

[0002] High energy density all-solid-state batteries have a Li-ion battery capacity of 4V or more. + This is achieved by applying an electrode active material having a redox potential vs. Li (a "4V class" positive electrode active material), which allows for high cell voltages. However, such positive electrode active materials may be incompatible with typical lithium ion conducting solid electrolyte materials used in solid-state batteries, since they may act as oxidants for the solid electrolyte present in the positive electrode and / or separator layers.

[0003] To solve this problem, it has been proposed to apply a coating to the positive electrode active material that acts as a protective layer to prevent the positive electrode active material from oxidizing the solid electrolyte without impeding the movement of lithium ions between the positive electrode active material and the solid electrolyte.

[0004] WO2020 / 249659A1 discloses a coated particulate material for use as an electrode and / or electrode active material in a solid-state lithium-ion electrochemical cell, the coated particulate material comprising a plurality of core particles, each core particle comprising at least one nickel-containing composite layered oxide, and a coating disposed on the surface of the core particles comprising carbonate ions, lithium and at least one further element. WO2020 / 249659A1 also discloses an electrode for use in a solid-state or lithium-ion electrochemical cell, and a respective electrochemical cell, the electrode comprising the coated particulate material. The coating comprises carbonate anions, lithium and at least one member of the group consisting of aluminum, boron, niobium, phosphorus, silicon, tantalum, titanium, zinc, zirconium and mixtures thereof. At least one member of the group consisting of aluminum, boron, niobium, phosphorus, silicon, tantalum, titanium, zinc, zirconium, and mixtures thereof is LiNbO3, Li2ZrO3, LiTaO3, Li3PO4, Li3BO3, LiAlO2, Li6ZnNb4O 14 and Zn3(PO4)2. 14 No examples of coatings containing zinc and niobium are provided. Furthermore, no examples are given of how to obtain a coating in which both zinc and niobium are present. In contrast, all exemplary coatings disclosed in WO2020 / 249659A1 contain niobium, and no further members of the group consisting of aluminum, boron, phosphorus, silicon, tantalum, titanium, zinc, and zirconium are present.

[0005] Related technology includes US2020 / 0388841A1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2020 / 249659A1 [Patent Document 2] US2020 / 0388841A1 Summary of the Invention [Problem to be solved by the invention]

[0007] Although the application of Li3NbO4 or a coating containing LiNbO3 to the positive electrode active material has been found to have beneficial effects on the initial discharge capacity as well as on cycling performance and stability, further improvements, i.e., increasing the initial capacity and reducing the capacity loss during cycling, are desirable. [Means for solving the problem]

[0008] According to a first aspect, C1) A plurality of core particles, each core particle having the formula (I): Li 1+t [Co x Mn y Ni z M u ] 1-t O2(I) (In the formula, 0≦x≦1 0≦y≦1 0≦z≦1 0≦u≦0.15 M, if present, is one or more elements selected from the group consisting of Al, Mg, Ba, B, and transition metals other than Ni, Co, and Mn; x+y+z>0 x+y+z+u=1 0≦t≦0.2) A plurality of core particles comprising or consisting of one or more compounds of and C2) a coating disposed on the surface of the core particle, - carbonate anion, - Lithium cation, and - niobium and zinc in oxidized form, where at least a portion of the niobium is present as cubic Li3NbO4 having a crystallographic unit cell of the space group Fm-3m; Including, Preferably, The proportion of Zn is in the range of 0.07% by mass to 0.1% by mass. The proportion of Nb is in the range of 0.4% by mass to 0.6% by mass. - the coating comprises a total amount of carbonate anions in the range of 0.08% by weight to 1.62% by weight; These are in each case relative to the total mass of the core particles. - a coating in which the molar ratio of Li:Nb is in the range of 0.5 to 5.0; There is provided a coated particulate material comprising or consisting of: [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows the first cycle charge / discharge curves at 0.1 C rate. [Diagram 2] FIG. 2 shows the average specific discharge capacity for rates ranging from 0.1C to 1C for three cells according to the invention and three comparative cells. [Diagram 3] FIG. 3 shows the average long-term cycling stability of three cells according to the invention and three comparative cells. [Figure 4] FIG. 4 shows the average coulombic efficiency up to cycle number 50 for three cells according to the invention and three comparison cells. [Diagram 5] FIG. 5 shows the Nyquist plot obtained from EIS measurements of a representative cell in the discharged state. [Figure 6] FIG. 6 shows the average long-term cycling stability of cells containing six different active cathode materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The compounds of formula (I) can act as positive electrode active materials in electrochemical cells. In the context of this disclosure, the electrode of an electrochemical cell that develops a net positive charge during cell discharge is referred to as the positive electrode (cathode), and the component of the positive electrode that is reduced to generate said net positive charge is referred to as the "positive electrode active material."

[0011] Preferably, each core particle C1) consists of at least one compound of formula (I).

[0012] The preferred positive electrode active material is Li + / Li (“4V class” positive electrode active materials), which allow high cell voltages to be obtained. Many such positive electrode active materials are known in the art.

[0013] Suitable positive electrode active materials include oxides containing lithium and one or more members of the group consisting of nickel, cobalt, and manganese.

[0014] According to the present invention, the positive electrode active material present in the core of the coated particulate material is represented by the general formula (I): Li 1+t [Co x Mn y Ni z M u ] 1-t O2(I) (In the formula, 0≦x≦1 0≦y≦1 0≦z≦1 0≦u≦0.15 M, if present, is one or more elements selected from the group consisting of Al, Mg, Ba, B, and transition metals other than Ni, Co, and Mn; x+y+z>0 x+y+z+u=1 0≦t≦0.2) The material is selected from the group consisting of materials having a composition according to

[0015] In certain active cathode materials according to formula (I), M may be one of Al, Mg, Ti, Mo, Nb, W, and Zr. Exemplary active cathode materials of formula (I) include Li 1+t [Ni 0.88 Co 0.08 Al 0.04 ] 1-t O2, Li 1+t [Ni 0.905 Co0.0475 Al 0.0475 ] 1-t O2 and Li 1+t [Ni 0.91 Co 0.045 Al 0.045 ] 1-t O2, where in each case 0≦t≦0.2.

[0016] Suitable positive electrode active materials are, for example, oxides containing lithium and one or more members of the group consisting of nickel, cobalt, and manganese. These positive electrode active materials have the general formula (Ia): Li 1+t [Co x Mn y Ni z ] 1-t O2(Ia) (In the formula, 0≦x≦1 0≦y≦1 0≦z≦1 x+y+z=1 0≦t≦0.2) The composition is as follows:

[0017] Preferably, the positive electrode active material according to general formula (Ia) is a mixed oxide of lithium and at least one of nickel and manganese. More preferably, the positive electrode active material is a mixed oxide of lithium, nickel and one or both members of the group consisting of cobalt and manganese.

[0018] Exemplary positive electrode active materials according to formula (Ia) include LiCoO2, Li 1+t [Ni 0.85 Co 0.10 Mn 0.05 ] 1-t O2, Li 1+t [Ni 0.87 Co 0.05 Mn 0.08 ] 1-t O2, Li 1+t [Ni 0.83 Co 0.12 Mn 0.05 ] 1-t O2 and Li 1+t [Ni 0.6 Co 0.2Mn 0.2 ] 1-t O2, where in each case 0≦t≦0.2.

[0019] Certain suitable positive electrode active materials include: - Lithium - Nickel and - one or both members of the group consisting of cobalt and manganese It is a mixed oxide comprising:

[0020] An exemplary suitable positive electrode active material has the general formula (Ib): Li 1+t A 1-t O2(Ib) The composition is During the ceremony, 0≦t≦0.2 A is nickel and one or both members of the group consisting of cobalt and manganese; Optional - one or more further transition metals not selected from the group consisting of nickel, cobalt and manganese, said further transition metals being preferably selected from the group consisting of molybdenum, titanium, tungsten, zirconium, - one or more elements selected from the group consisting of aluminum, barium, boron and magnesium, At least 50 mole percent of the transition metal in A is nickel.

[0021] Suitable positive electrode active materials having a composition according to formula (Ib) are described, for example, in WO2020 / 249659A1.

[0022] The positive electrode active material having a composition according to general formula (I), in particular according to general formula (Ib), may have a layered structure or a spinel structure. The positive electrode active material having a composition according to general formula (Ib) having a layered structure as described in WO2020 / 249659A1 may be preferred in some cases.

[0023] Certain preferred positive electrode active materials have the general formula (Ic): Li 1+t [Ni 1-u-v-w Co u Mn v M w ] 1-t O2(Ic) The composition is During the ceremony, M is a member of the group consisting of aluminum, barium, boron, magnesium, molybdenum, titanium, tungsten, zirconium, and mixtures of at least two of the foregoing elements, preferably M is or comprises aluminum (most preferably when v is 0); t is a number in the range of 0 to 0.2, u is a number in the range of 0.04 to 0.2, v is a number in the range of 0 to 0.2, preferably 0.04 to 0.2, w is a number in the range of 0 to 0.1, and (u+v+w) is ≦0.4, and preferably ≦0.3.

[0024] In formula (Ic), the variable "M" can represent any individual member of the group of elements defined above (e.g., "M" can represent tungsten, i.e., "W"), or can represent two or more members of the group of elements defined above (e.g., "M" can represent the group consisting of tungsten, zirconium, and titanium). When "M" represents two or more members of the group of elements defined above, the index (number) "w" associated with the variable "M" applies to the sum of the elements represented by "M" as defined above.

[0025] Exemplary positive electrode active materials of formula (Ic) include Li 1+t [Ni 0.85 Co 0.10 Mn 0.05 ] 1-t O2, Li 1+t [Ni 0.87 Co 0.05 Mn 0.08 ] 1-t O2, Li 1+t [Ni 0.83 Co0.12 Mn 0.05 ] 1-t O2, Li 1+t [Ni 0.6 Co 0.2 Mn 0.2 ] 1-t O2, Li 1+t [Ni 0.88 Co 0.08 Al 0.04 ] 1-t O2, Li 1+t [Ni 0.905 Co 0.0475 Al 0.0475 ] 1-t O2 and Li 1+t [Ni 0.91 Co 0.045 Al 0.045 ] 1-t O2, where 0≦t≦0 in each case.

[0026] In the coated particulate matter described herein, the coating C2) is - carbonate anion, - Lithium cation, and - niobium and zinc in oxidized form, where at least a portion of the niobium is present as cubic Li3NbO4 having a crystallographic unit cell of the space group Fm-3m; Includes.

[0027] Cubic Li3NbO4 has the rock-salt structure.

[0028] The coating includes at least one crystalline phase including cubic Li3NbO4 having a crystallographic unit cell of space group Fm-3m as determined by nanobeam electron diffraction.

[0029] Preferably, less than 10% of the niobium present in the coating is Li6ZnNb4O 14 and more preferably less than 5%, more preferably less than 1%, of the niobium present in the coating is in the form of Li6ZnNb4O 14 Most preferably, it is present in the monoclinic phase of Li6ZnNb4O. 14is not present in the coated particulate material.

[0030] In the coated particulate material described herein, the molar ratio Nb:Zn is in the range 3-5, preferably in the range 4.1-5.

[0031] In coating C2), Zn is Zn 2+ It exists in the form of a cation or in the form of an oxoanion or hydroxoanion (zincate anion).

[0032] In coating C2), at least a portion of the zinc may be present in a compound having a composition derived from the parent composition Li3NbO4 or LiNbO3, where Li and / or Nb are partially replaced by Zn. Without wishing to be bound by any theory, it is currently believed that compounds having a composition derived from the parent composition Li3NbO4, where Li and / or Nb are partially replaced by Zn, have the following general formula (II): Li (3-2a) Zinc (a+b) Nb (1-0.4b) O4(II) (In the formula, 0≦a<1.5 0≦b<0.25 0<(a+b)<1.75 It is envisioned that the above can be described by:

[0033] The compound of formula (II) is regarded as Zn-doped Li3NbO4.

[0034] In the coated particulate material described herein, The proportion of Zn may be in the range of 0.07% by mass to 0.1% by mass, and / or The proportion of Nb may be in the range of 0.4% to 0.6% by mass, These are in each case relative to the total mass of the core particles.

[0035] Preferably, in the coated particulate material described herein, The proportion of Zn is in the range of 0.07% by mass to 0.2% by mass, preferably 0.07% by mass to 0.1% by mass. and the proportion of Nb is in the range of 0.35% by mass to 0.6% by mass, preferably 0.4% by mass to 0.6% by mass; These are in each case relative to the total mass of the core particles.

[0036] The mass percentages of Li, Zn and Nb may be determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES), said analytical technique being known in the art.

[0037] If Nb is present in the coating C2) as well as in the core particles C1), the amount of Nb present in the coating C2) is preferably determined by comparing (i) the amount of Nb in a sample of said core particles C1) measured (determined) before coating with (ii) the amount of Nb present in the same sample measured (determined) after coating. The same approach is used to determine the amount of Li in the coating C2), since Li is also present in the core C1).

[0038] More preferably, in the coated particulate material described herein, the proportion of Zn is in the range of 0.07% by mass to 0.2% by mass, preferably 0.07% by mass to 0.1% by mass; and the proportion of Nb is in the range of 0.35% by mass to 0.6% by mass, preferably 0.4% by mass to 0.6% by mass; in each case relative to the total mass of the core particles, The molar ratio of Nb:Zn is in the range of 3-5, and preferably in the range of 4.1-5.

[0039] The molar amount of Nb in the coating C2) per 1 g of the plurality of core particles is preferably in the range of 6 to 540 μmol / g, preferably in the range of 6 to 270 μmol / g, more preferably in the range of 6 to 108 μmol / g, relative to the total mass of the plurality of core particles.

[0040] In the coated particulate matter described herein, the coating C2) is disposed on the surface of at least a portion of the core particles C1) present in the coated particulate matter, preferably the coating C2) is disposed on the surface of >50% of the total number of core particles C1), more preferably on the surface of ≥75% of the total number of core particles C1), even more preferably on the surface of ≥90% of the total number of core particles C1), and even more preferably on the surface of ≥95% of the total number of core particles C1). For the purposes of the present disclosure, the portion of the core particles C1) on whose surface the coating C2) is disposed can be determined by electron microscopy performed on a (representative) sample of the coated particulate matter.

[0041] In the coated particulate matter described herein, the coating C2) is disposed on at least a part of the surface of the (individual) core particle C1), preferably the coating C2) is disposed on >50% of the total surface of the core particle C1), more preferably on ≧75% of the total surface of the core particle C1), and even more preferably on ≧90% of the total surface of the core particle C1). For the purposes of the present disclosure, the part of the surface of the core particle C1) on which the coating C2) is disposed can be determined by electron microscopy performed on a (representative) sample of the (individual) coated particles of the coated particulate matter or on a (representative) sample of the coated particulate matter.

[0042] In the coated particulate material according to the first embodiment described herein, the coating C2) may comprise carbonate anions in a total amount of ≧0.08% by weight relative to the total weight of the plurality of (uncoated) core particles C1). More specifically, the coating C2) may comprise carbonate anions in a total amount ranging from 0.08% to 1.62% by weight, preferably ranging from 0.122% to 1.22% by weight, more preferably ranging from 0.162% to 0.812% by weight relative to the total weight of the plurality of (uncoated) core particles C1). If the content of lithium carbonate in the coating C2) is too high, the lithium ion conductivity may decrease.

[0043] Without wishing to be bound by any theory, it is currently assumed that the carbonate present on the surface of the core particles C1) results from inevitable impurities of the positive electrode active material that may be formed when the positive electrode active material is prepared or stored in the presence of traces of carbon dioxide and moisture, and / or, in certain cases, from the use of lithium carbonate as a precursor for the synthesis of the positive electrode active material, and / or from the decomposition of the organic solvent of the liquid reaction mixture used in the preparation of the coated particulate material (see below for details) in air or oxygen, respectively, and reactivity with the residual lithium on the particle surface of the positive electrode active material.

[0044] In the coated particulate material according to the first embodiment described herein, at least a portion of the carbonate ions present in the coating C2) may be present as part of an ionic compound, for example as part of a salt, where at least a portion of the carbonate ions present in the coating C2), preferably the total amount of carbonate ions present in the coating C2), is present as lithium carbonate.

[0045] For the purposes of the present disclosure, the amount of carbonate ions present in the coating C2) may be determined by acid titration combined with mass spectrometry, more preferably carried out on a (representative) sample of the coated particulate matter and according to the method defined in the Examples section of WO2020 / 249659A1.

[0046] In the coated particulate matter, the lithium present in the coating C2) is preferably - As part of cubic Li3NbO4 with a crystallographic unit cell of space group Fm-3m as part of one or more compounds having a composition derived from the parent composition Li3NbO4 or LiNbO3, where Li and / or Nb are partially replaced by Zn - and as part of lithium carbonate (Li2CO3) exist.

[0047] The molar ratio of Li:Nb in the coating C2) is preferably in the range of 0.5 to 5.0, preferably in the range of 0.75 to 4.5, more preferably in the range of 1.0 to 4.0, more preferably in the range of 1.1 to 1.6.

[0048] In coating C2), nanocrystals of cubic Li3NbO4 may be embedded in a matrix formed of lithium carbonate.

[0049] Lithium carbonate can be present in a crystalline phase and an amorphous phase. At least one of the crystalline phase and the amorphous phase containing lithium carbonate is present in the coating C2) of the coated particles.

[0050] Coating C2) may comprise lithium carbonate in a total amount in the range of 0.1% to 2.0% by weight, more preferably in the range of 0.15% to 1.5% by weight, and even more preferably in the range of ≧0.15% to 1.0% by weight, relative to the total weight of the plurality of core particles. The total weight (or molar amount) of lithium carbonate in coating C2) is preferably determined (calculated) as follows: first, the molar amount (or mass) of carbonate anions present in coating C2) is determined by acid titration combined with mass spectrometry, as explained above. Then, for the purposes of the calculations of the present invention, it is assumed that the total molar amount (or mass) of carbonate ions found in coating C2) is present only as Li2CO3.

[0051] According to a second aspect, there is provided a method for preparing a coated particulate material according to the first aspect described above, said method comprising the steps of: P1) preparing or providing a plurality of core particles C1) as defined above, P2) preparing or providing a liquid composition comprising a solvent and lithium ions at least partially dissolved in said solvent; P3) preparing or providing a liquid composition comprising an organic solvent and zinc ions at least partially dissolved in said organic solvent, and a liquid composition comprising an organic solvent and niobium ions at least partially dissolved in said organic solvent, or a liquid composition comprising an organic solvent and zinc ions and niobium ions at least partially dissolved in said organic solvent, P4) contacting the components prepared or provided in steps P1) to P3) with each other to obtain a reaction mixture; P5) removing the solvent from the reaction mixture obtained from step P4) to obtain a solid residue; P6) heat treatment of the solid residue obtained from step P5) at a temperature ranging from 100° C. to 600° C., preferably from 250° C. to 550° C., to obtain a coated particulate material according to the first aspect defined above. Includes.

[0052] Methods for the preparation (step (P1)) of core particles C1) comprising, preferably consisting of, at least one active cathode material are known in the art. Core particles C1) comprising or consisting of at least one active cathode material are commercially available. For preferred specific active cathode materials, reference is made to the disclosure provided above in the context of the coated particulate material according to the first embodiment. To reduce the amount of residual surface carbonate, step P1) may comprise a heat treatment of the core particles C1). The heat treatment of the core particles C1) may be carried out at a temperature in the range of 700-800° C. The heat treatment of the core particles C1) may be carried out in the presence of an oxygen flow.

[0053] The liquid compositions provided in steps P2) and P3) comprise precursors for the coating C2).

[0054] In step P2), a liquid composition containing lithium ions may be prepared by dissolving lithium metal in a solvent selected from the group consisting of water, ethanol, methanol, isopropanol, butanol, acetone, tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) and mixtures thereof. The preferred solvent is absolute ethanol.

[0055] In process P3), - below, - a first liquid composition comprising an organic solvent and zinc ions at least partially dissolved in said organic solvent; and a second liquid composition comprising an organic solvent and niobium ions at least partially dissolved in said organic solvent. mosquito, Or a single liquid composition comprising an organic solvent and zinc ions and niobium ions at least partially dissolved in said organic solvent. The liquid composition is prepared by dissolving one or both of (i) a niobium precursor selected from the group consisting of niobium alkoxides and niobium nitrates, and (ii) a zinc precursor selected from the group consisting of zinc alkoxides, zinc acetates, and zinc nitrates, in a solvent selected from the group consisting of ethanol, methanol, isopropanol, butanol, acetone, tetrahydrofuran (THF), and N,N-dimethylformamide (DMF), and mixtures thereof. A preferred solvent is absolute ethanol. A preferred niobium precursor is niobium ethoxide. A preferred zinc precursor is zinc acetate.

[0056] The molar ratio Nb:Zn provided in step P3) is preferably in the range of 3-5, more preferably in the range of 4.1-5.

[0057] The molar ratio of Li provided in step P2) to Nb provided in step P3) is preferably in the range of 0.5 to 5.0, preferably in the range of 0.75 to 4.5, more preferably in the range of 1.0 to 4.0.

[0058] In step P4) of the method according to the second aspect described herein, the components prepared or provided in steps P1) to P3) can be brought into contact with each other by any suitable technique, for example by mixing the components and / or by spraying the liquid composition or a mixture thereof prepared or provided in steps P2) and P3 onto the core particles C1) prepared or provided in step P1). For enhanced or complete contact, ultrasonication can be used, preferably at a temperature ranging from 15° C. to 30° C. for a time ranging from 15 minutes to 60 minutes, for example to finalize the preparation of a reaction mixture in the form of a dispersion or gel. Thus, in step P4), the contacting can include the preparation of a dispersion comprising the particles prepared or provided in step P1) and a mixture of the liquid composition prepared or provided in steps P2) and P3), followed by ultrasonication of said dispersion. A mixture of the solutions prepared or provided in steps P2) and P3) may be formed before the addition of the core particles C1) prepared or provided in step P1).

[0059] In the reaction mixture obtained in step P4), the molar ratio Nb:Zn provided in step P3) is preferably in the range of 3-5, more preferably in the range of 4.1-5, and the molar ratio of Li:Nb is preferably in the range of 0.5-5.0, preferably in the range of 0.75-4.5, more preferably in the range of 1.0-4.0.

[0060] Preferably, steps P1) to P4) are carried out under a protective gas atmosphere (for example argon or nitrogen).

[0061] In step P5), removal of the solvent of the liquid reaction mixture (prepared in step (i)) is preferably achieved by subjecting the solution to reduced pressure (relative to standard pressure of 101.325 kPa) at a temperature in the range of 0°C to 100°C, preferably in the range of 20°C to 40°C.

[0062] In step P6), heat treating the solid residue may comprise calcining the solid residue. The heat treatment in step P6) may be carried out in the presence of an oxygen flow. Most preferably, the heat treatment is carried out at a temperature in the range of 450°C to 550°C.

[0063] In step P6), the solid residue may be comminuted before the heat treatment.

[0064] In step P6), after removal of the solvent, a heat treatment is carried out for 1 hour to 12 hours, preferably 1 hour to 6 hours, more preferably 2 hours to 4 hours, at a temperature in the range of 200°C to 600°C or less, preferably 250°C to 550°C, most preferably 450°C to 550°C.

[0065] Surprisingly, despite the molar ratio of Nb:Zn being close to 4:1, the monoclinic phase Li6ZnNb4O 14 It has been found that this is substantially not obtainable by the method according to the second aspect.

[0066] According to a third aspect, there is provided an electrode for use in an electrochemical cell, in particular an all-solid-state lithium-ion electrochemical cell, said electrode comprising: E1) a total amount of coated particulate matter according to the first aspect defined above, preferably between 50% and 99% by weight, more preferably between 70% and 97% by weight, relative to the total weight of the electrode, E2) A lithium ion conductive solid electrolyte material in a total amount of preferably 1% by mass to 50% by mass, more preferably 3% by mass to 30% by mass, based on the total mass of the electrode; E3) optionally electronically conducting carbon; E4) Optionally, one or more binders Includes.

[0067] In the electrode according to the third aspect, the coated particulate material E1) according to the first aspect disclosed above or provided by the method according to the second aspect disclosed above, the solid electrolyte material E2) as defined above and optionally the further components E3) and E4) may be mixed with each other.

[0068] The disclosure regarding the coated particulate material provided above in the context of the first and second aspects applies mutatis mutandis to the electrode according to the third aspect. With regard to preferred specific coated particulate materials, reference is made to the disclosure provided above in the context of the coated particulate material according to the first aspect.

[0069] Typically, the electrode according to the third aspect described herein is the positive electrode, i.e. the electrode of the electrochemical cell which develops a net positive charge during discharge of the cell.

[0070] In the electrode according to the third embodiment described herein, the coating C2) serves the purpose of facilitating the transfer of lithium ions between (i) the active cathode material (present in the core C1) of the coated particulate matter) and (ii) the solid electrolyte E2). Furthermore, the active cathode material is capable of withstanding a Li + / Li (positive electrode active material of "4V class"), and the solid electrolyte has a redox potential of 4V or less Li +If the coating C2) does not have electrochemical oxidation stability against / Li, it acts as a protective layer protecting the solid electrolyte E2) from oxidation by the positive electrode active material.

[0071] Suitable solid electrolyte materials capable of conducting lithium ions are known in the art. For example, the solid electrolyte E2) may be selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxyphosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides. Here, the term "lithium-containing" means that lithium cations are present in the electrolyte, but cations of metals other than lithium may also be present in the chemical compounds forming the solid electrolyte.

[0072] Such solid electrolytes have good lithium ion conductivity but are sometimes susceptible to oxidation by the active cathode material, especially in the case of 4V class active cathode materials. In the electrode according to the third embodiment, the coating C2) serves as a protective layer that protects the solid electrolyte E2) from oxidation by the active cathode material present in the core C1) of the coated particulate matter E1).

[0073] Alternatively, in the electrode according to the third aspect described herein, the solid electrolyte material incorporated in the coated particulate material according to the first aspect disclosed above or provided by the method according to the second aspect disclosed above may be a solid material having a composition present in the coating C2) of the coated particulate material of the electrode. By applying a solid material having a composition present in the coating C2) as the solid electrolyte E2) of the electrode, the variety of materials present in the electrode is reduced, thus reducing the complexity of the electrode and eliminating undesirable interactions between the different materials present in the electrode. Furthermore, the presence of the same material in the coating C2) and in the solid electrolyte E2) of the coated particles creates favorable conditions for the transfer of lithium ions between the electrode active material (present in the core C1) of the coated particulate material) and the solid electrolyte.

[0074] In the electrode according to the third aspect defined herein, the coated particulate material E1) and the solid electrolyte material E2) provided by the method according to the first aspect disclosed above or according to the second aspect disclosed above may be mixed with each other and with one or more binders E4) and / or one or more electronically conductive materials E3). Exemplary electronically conductive materials E3) include or consist of elemental carbon, such as carbon nanofibers, carbon nanotubes, graphene, carbon black, acetylene black, coke, and graphene oxide. Exemplary binders include poly(vinylidene fluoride) (PVDF), styrene butadiene rubber (SBR), polyisobutene, poly(ethylene vinyl acetate), and poly(acrylonitrile butadiene).

[0075] The electrode according to the third aspect as defined herein may comprise coated particulate material provided by the method according to the first aspect disclosed above or according to the second aspect disclosed above in a total amount of 50% to 99%, more preferably 70% to 97%, based on the total mass of the electrode (without current collector, same below).

[0076] The electrode according to the third aspect as defined herein may comprise a total amount of solid electrolyte ranging from 1% to 50%, more preferably from 3% to 30%, relative to the total mass of the electrode.

[0077] Optionally, the electrode according to the third aspect defined herein may comprise an electronically conductive material comprising or consisting of elemental carbon in a total amount of from 0% to 5%, more preferably from 0% to 1%, relative to the total mass of the electrode.

[0078] Optionally, the electrode according to the third aspect defined herein may comprise a binder in a total amount of 0.1% to 3% relative to the total mass of the electrode.

[0079] Preferred electrodes according to the third aspect defined herein are those which have one or more of the particular preferred features disclosed herein.

[0080] The present invention also relates to a method for producing an electrode according to the third aspect described above, said method comprising the steps of: M1) Providing at least one coated particulate material E1) according to the first aspect or obtainable by the method according to the second aspect. M2) Providing at least one solid electrolyte material E2) M3) optionally providing one or both of the further components E3) and E4) defined above. M4) mechanically mixing the components provided in steps M1) to M3) with one another and, optionally, adding a solvent; M5) compressing the mixture obtained in step M4) at a pressure higher than atmospheric pressure or applying the mixture obtained in step M4) onto a current collector, followed by optional removal of the solvent. to obtain an electrode.

[0081] The disclosure provided above in the context of the coated particulate material in the first and second aspects and the disclosure in the context of the electrode according to the third aspect apply mutatis mutandis. For preferred specific coated particulate materials, reference is made to the disclosure provided above in the context of the coated particulate material in the first aspect. For preferred specific electrode components E2), E3) and E4), reference is made to the disclosure provided above in the context of the electrode according to the third aspect.

[0082] In step M4), a complex comprising electrode components E1) and E2, and optionally one or both of E3) and E4), and optionally a solvent, can be prepared by mechanical mixing (e.g. by planetary or ball milling).

[0083] In step M5) of the method for producing an electrode, the pressure above atmospheric pressure is preferably in the range of 1 to 450 MPa, more preferably in the range of 50 to 450 MPa, and even more preferably in the range of 75 to 400 MPa.

[0084] The present invention also relates to an electrode obtainable by the method according to the fourth aspect described above.

[0085] The present invention also relates to the use of a coated particulate material according to the first aspect or prepared by the method according to the second aspect for preparing an electrode according to the third aspect as defined above. The disclosure provided above regarding the coated particulate material in the context of the first and second aspects and the disclosure regarding the electrode according to the third aspect applies mutatis mutandis. With regard to preferred specific coated particulate materials, reference is made to the disclosure provided above in the context of the coated particulate material according to the first aspect.

[0086] According to a further aspect there is provided an electrochemical cell comprising a coated particulate material provided by the method according to the first aspect disclosed above or according to the second aspect disclosed above.

[0087] In said cell, preferably the coated particulate matter may be present in an electrode, particularly the positive electrode, according to the third aspect disclosed above.

[0088] The electrochemical cell defined above comprises the following components: α) at ​​least one negative electrode β) at least one positive electrode; γ) at least one separator; The rechargeable electrochemical cell may include

[0089] The electrochemical cells described herein may be alkali metal containing cells, particularly lithium ion containing cells. In lithium ion containing cells, charge transfer occurs through Li +ions. In the separator, such an electrochemical cell may contain a solid electrolyte selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxyphosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides. Preferably, the solid electrolyte of the separator has the same composition as the solid electrolyte E2) of the electrodes, so that the variety of substances present in the cell is reduced, thus reducing the complexity of the cell and eliminating undesirable interactions between the different substances present in the cell. Furthermore, the presence of the same substances in the solid electrolyte E2) and in the separator creates favorable conditions for the migration of lithium ions between the electrodes and the solid electrolyte of the separator.

[0090] Suitable separator materials, electrochemically active cathode materials (positive electrode active materials), and suitable electrochemically active anode materials (negative electrode active materials) are known in the art. Exemplary positive electrode active materials are disclosed above in the context of the first embodiment. The negative electrode active materials can reversibly plate and strip lithium metal and deintercalate and intercalate lithium ions, respectively. In the electrochemical cells described herein, the anode α) can include, as the negative electrode active material, graphitic carbon, lithium metal, or a metal alloy containing lithium.

[0091] The electrochemical cell may be an all-solid-state electrochemical cell.

[0092] In certain embodiments, the electrochemical cell according to the present invention comprises: a cathode which is an electrode according to the third aspect described above a separator layer comprising a solid electrolyte selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxyphosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides; - an anode comprising a negative electrode active material capable of reversibly plating and stripping lithium metal and de-intercalating and intercalating lithium ions, respectively; Includes.

[0093] In said electrochemical cell, the coating C2) present on the respective coated particulate material obtained by the method according to the first aspect defined above and according to the second aspect defined above separates the positive active material from the lithium ion conducting separator layer. The positive active material in the core C1) is coated with the respective coating C2) obtained by the method according to the first aspect defined above and according to the second aspect defined above, so that direct contact between the positive active material and the lithium ion conducting separator layer is prevented. Thus, by coating the positive active material in the core C1) with the respective coating C2) obtained by the method according to the second aspect defined above and according to the first aspect defined above, an electrochemical cell, in particular an all-solid-state lithium battery, can be realised, which has a Li ion conducting separator layer of 4 V or more. + A positive electrode active material having a redox potential relative to Li is combined with a solid electrolyte E2) and a separator layer. The separator layer itself has a redox potential of 4 V or more relative to Li. + The solid electrolyte for the separator layer may comprise or consist of a lithium ion conducting material that does not exhibit oxidative stability at redox potentials vs. / Li, such as a sulfide-based, thiophosphate-based or oxysulfide-based solid electrolyte. Such lithium ion conducting materials that do not have high oxidative stability often exhibit one or more favorable properties, such as stability in the presence of lithium metal or a metal alloy containing lithium, easy processability, good ionic conductivity and low cost, making them suitable for forming the solid electrolyte layer and the separator layer, respectively. Thus, the solid electrolyte for the separator layer may be suitably selected according to the criteria of stability in the presence of lithium metal or a metal alloy containing lithium, ionic conductivity, processability and cost, while oxidative stability is not an issue.

[0094] Thus, by coating the cathode active material with the coating C2) described above in the context of the first embodiment, it is possible to realize electrochemical cells, in particular all-solid-state lithium batteries, with Li / Li capacities of 4 V or more. + A positive electrode active material having an oxidation-reduction potential relative to the positive electrode is combined with a solid electrolyte E2) and / or a separator layer, the separator layer comprising or consisting of a lithium ion conductive material, the lithium ion conductive material having a redox potential of 4 V or more by itself. + Although the solid electrolyte does not exhibit oxidative stability at redox potentials versus Li / Li (e.g., sulfide-based solid electrolytes), it does exhibit one or more favorable properties, such as stability in the presence of lithium metal or a metal alloy containing lithium, good ionic conductivity, and easy processability, making the solid electrolyte suitable for forming a solid electrolyte layer, a separator layer, respectively.

[0095] The electrochemical cell may have a disk-like or prismatic shape. The electrochemical cell may include a housing, which may be made of steel or aluminum.

[0096] A plurality of the electrochemical cells described above can also be combined into an all-solid-state battery having both solid electrodes and solid electrolytes. A further aspect of the present disclosure refers to a battery, more specifically an alkali metal ion battery, in particular a lithium ion battery comprising at least one electrochemical cell as described above, such as two or more electrochemical cells as described above. The electrochemical cells described above can be combined with each other in an alkali metal ion battery, for example in series or parallel connection. A series connection is preferred.

[0097] Each of the electrochemical cells or batteries described herein may be used to manufacture or operate stationary applications such as automobiles, computers, personal digital assistants, cell phones, watches, video cameras, digital cameras, thermometers, calculators, laptop BIOS, communication devices, remote car locks, and energy storage devices for power plants. A further aspect of the present invention is a method for manufacturing or operating stationary applications such as automobiles, computers, personal digital assistants, cell phones, watches, video cameras, digital cameras, thermometers, calculators, laptop BIOS, communication devices, remote car locks, and energy storage devices for power plants by using at least one battery of the present invention or at least one electrochemical cell of the present invention.

[0098] A further aspect of the present disclosure is the use of an electrochemical cell as described above in an automobile, a bicycle operated by an electric motor, a robot, an aircraft (e.g. an unmanned aerial vehicle including a drone), a ship or a stationary energy storage device.

[0099] The present disclosure further provides a device comprising at least one electrochemical cell of the present invention as described above.Preferred is a mobile device, such as a vehicle, for example a car, a bicycle, an aircraft, or a water vehicle, such as a boat or ship.Other examples of mobile devices are portable, such as a computer, especially a laptop, a telephone, or a power tool (for example in the construction sector), especially a drill, a battery-powered screwdriver, or a battery-powered tacker.

[0100] The present invention is further illustrated by the following examples which should not be construed as limiting the invention. EXAMPLES

[0101] 1. Preparation of Materials Process P1) LiNi as positive electrode active material (CAM) 0.85 Co 0.10 Mn 0.05Core particles C1) containing O2 (NCM-851005; BASF SE, also referred to herein as NCM) were heated at 750 °C for 3 h in flowing O2 to reduce the amount of residual surface carbonate. The heating and cooling rates were set at 5 °C / min.

[0102] A portion of the core particles was left uncoated and used for comparative experiments (referred to herein as "uncoated").

[0103] Process P2) A 1 M lithium ethoxide solution was prepared by reacting absolute ethanol (Sigma-Aldrich; 99.8%) with Li metal (Albemarle Germany GmbH).

[0104] Process P3) To prepare 0.5 M niobium ethoxide and 0.01 M zinc acetate solutions, Nb(OCH2CH3)5 (Sigma-Aldrich; 99.95%) and Zn(O2CCH3)2 (Sigma-Aldrich) were dissolved in absolute ethanol.

[0105] Process P4)-P6) In an Ar-filled glove box, an amount of 5.94 g of core particles provided in step P1) was added to the lithium ethoxide solution (512 μL) prepared in step P2) and to a mixture of niobium ethoxide solution (683 μL) and zinc acetate solution (8500 μL) prepared in step P3), then the dispersion was sonicated for 30 minutes, thereby obtaining a reaction mixture in the form of a dispersion (step P4)). The reaction mixture was then dried overnight in vacuum (step P5)). The powder obtained was ground with a mortar and pestle and heated in a stream of oxygen at 300 °C or 500 °C in each case for 2 hours (heating rate 5 °C / min) (step P6)). Based on the amount of Nb and Zn applied, the coated particles according to the invention thus obtained were in the monoclinic phase Li6ZnNb4O 14 was found to be non-existent, but Li6ZnNb4O 14(see below). With reference to the temperature applied in step P6), the coated particulate materials according to the invention are called "Coated-inv300" and "Coated-inv500".

[0106] For comparison, coated particulates were prepared using reaction mixtures that did not contain zinc acetate (not according to the invention).

[0107] A first coated particulate material not according to the invention ("Coated-non-inv1") was prepared as follows: In an Ar-filled glove box, an amount of 5.94 g of NCM core particles provided in step P1) was added to a mixture of the lithium ethoxide solution prepared in step P2) (512 μL), the niobium ethoxide solution prepared in step P3) (683 μL), and 8500 μL of absolute ethanol, and the dispersion was then sonicated for 30 minutes, thereby obtaining a reaction mixture in the form of a dispersion (step P4)). The reaction mixture was then dried overnight in vacuum (step P5)). The powder obtained was ground with a mortar and pestle and heated at 300 °C for 2 hours in a flow of oxygen (heating rate 5 °C / min) (step P6)).

[0108] A second coated particulate material not according to the invention ("Coated-non-inv2") was prepared as follows: In an Ar-filled glove box, an amount of 5.94 g of NCM core particles provided in step P1) was added to a mixture of the lithium ethoxide solution prepared in step P2) (1024 μL), the niobium ethoxide solution prepared in step P3) (683 μL), and 8500 μL of absolute ethanol, and the dispersion was then sonicated for 30 minutes, thereby obtaining a reaction mixture in the form of a dispersion (step P4)). The reaction mixture was then dried overnight in vacuum (step P5)). The powder obtained was ground with a mortar and pestle and heated at 300° C. for 2 hours in a flow of oxygen (heating rate 5° C. / min) (step P6)). Based on the amount of Li and Nb applied in the coating of the particles, the molar ratio Li:Nb was 3:1.

[0109] A third coated particulate material not according to the invention ("Coated-non-inv3") was prepared as follows: In an Ar-filled glove box, an amount of 5.94 g of NCM core particles provided in step P1) was added to a mixture of the lithium ethoxide solution prepared in step P2) (406 μL), the niobium ethoxide solution prepared in step P3) (812 μL), and 1000 μL of absolute ethanol, and the dispersion was then sonicated for 30 minutes, thereby obtaining a reaction mixture in the form of a dispersion (step P4)). The reaction mixture was then dried overnight in vacuum (step P5)). The powder obtained was ground with a mortar and pestle and heated at 350° C. for 2 hours in a flow of oxygen (heating rate 5° C. / min) (step P6)). Based on the amounts of Li and Nb applied, the molar ratio Li:Nb in the coating of the particles was 1:1.

[0110] 2. Investigation of the structure and chemical composition of coated particulate matter according to the invention Scanning electron microscopy analysis was performed using a LEO-1530 electron microscope (Carl Zeiss AG) equipped with a field emission source at an accelerating voltage of 10 kV. Scanning electron microscopy (SEM) images (not shown) of the uncoated cathode active material prepared in step P1) and the coated particulate material according to the invention obtained after step P6) show an amount of agglomerated coating material randomly distributed on the core particles of the coated particulate material according to the invention. The morphology of the core particles remained substantially unchanged. Both of these observations were made regardless of the temperature of the heat treatment carried out in step P6).

[0111] Attenuated total reflection infrared spectroscopy was performed using an ALPHA FT-IR spectrometer (Bruker) equipped with a Ge crystal. The presence of Li2CO3 in the uncoated core particles and coated particulate matter was confirmed by ATR-IR spectroscopy, with slight differences between the spectra of the uncoated core particles and the coated particulate matter (not shown), regardless of the temperature of the heat treatment performed in step P6). This result indicates that the surface impurities at the time of synthesis remained and that the carbonate content did not change significantly upon coating.

[0112] X-ray diffraction (XRD) was used to evaluate possible changes in the lattice structure of the coated particulate material compared to uncoated core particles. XRD data were collected in Debye-Scherrer geometry using a Stadi-P diffractometer (STOE) equipped with a Mo anode (λ = 0.70926 Å) and a MYTHEN 1K strip detector (Dectris). Instrument contributions to reflection broadening were obtained by measuring a NIST 640f Si standard. Rietveld refinements were performed using GSAS-II. The scale factor, zero shift, and crystallite size broadening parameters were varied during refinement. The absorption of the sample was calculated based on a capillary diameter of 0.3 mm and a powder packing density of 1.44 g / cm3. A fixed background was fitted to the data using a Chebyshev polynomial function with 17 terms. The unit cell parameters for each site, oxygen site positions, and atomic displacement parameters (isotropic, uiso) were refined. Atoms occupying the same site were constrained to have the same atomic parameters and the site occupancy was constrained such that each site remained fully occupied. Regardless of the temperature of the heat treatment performed in step P6), all reflections in the patterns of the different samples (not shown) could be indexed within the R-3m space group (α-NaFeO2-type structure), as expected for the NCM material present in core C1).

[0113] The microstructure of the coatings was observed using a transmission electron microscope (TEM) (not shown). TEM characterization was performed using a double aberration-corrected Themis-Z microscope (ThermoFisher Scientific) equipped with a Oneview IS camera (Ametek) at an accelerating voltage of 300 kV, a Super-X EDX detector (ThermoFisher Scientific), and a high-resolution GIF Continuum970 (Ametek) electron energy loss spectrometer. 4D-STEM data sets were collected using the OneView IS camera with a screen current of about 10 pA, a convergence half angle of 0.47 mrad, and a camera length of 580 mm. Virtual imaging of nanobeam electron diffraction (NBED) patterns was performed using DigitalMicrograph (version 3.42). Sample cross sections were prepared using a dual-beam focused Ga ion beam (FIB) on a Strata400 (ThermoFisher Scientific). A carbon layer was deposited by ion-beam-induced deposition to protect the coatings during sample preparation and processing. Initial thinning was performed at 30 kV. Final thinning and cleaning of the samples was performed at a lower voltage of 5 kV / 2 kV.

[0114] High-resolution TEM (HRTEM) images (not shown) revealed a shell on the outer surface of NCM-851005 particles. The thickness of this shell ranged from a few nanometers to a few tens of nanometers and appeared to be larger at the outward-facing grain boundaries. The presence of an uncoated surface was also considered.

[0115] A clear separation of the core C1) and the coating C2) was observed in high-angle annular dark-field scanning TEM (HAADF-STEM) mode (not shown). Elemental maps of Nb and Ni obtained by energy dispersive X-ray spectroscopy (EDS) of the surface area of ​​the particle cross-sections prepared by focused ion beam (FIB) were consistent with the expected location of Ni in the core C1) and Nb in the coating C2). No diffusion of Nb into the core C1) was observed, consistent with the expectation considering the size and charge of the Nb ions. Elemental maps of Zn suggested the presence of Zn in both the coating C2) and the core C1). However, the EDS results were not clear due to the low content of Zn. This issue could not be resolved by electron energy loss spectroscopy (EELS) because of the overlap of the L-edge of Ni (1008 eV) and that of Zn (1020 eV) and / or the low amount of Zn compared to Ni. Further studies are therefore required to elucidate the specific role of Zn in the coating.

[0116] Using nanobeam electron diffraction (NBED), the presence of crystalline species in the amorphous matrix was confirmed for coating C2) (not shown). Virtual dark field images (not shown) revealed the presence of monoclinic phase Li6ZnNb4O 14 Unlike the lattice spacings observed, many nanoparticles with cubic crystal lattices were observed. The measured lattice spacings were in good agreement with those of rock-salt type (Fm-3m space group) lithium niobium oxides and related compounds such as Li3NbO4. In addition, the broad reflections observed at low diffraction angles, which are not indicative of the Fm-3m space group, were likely due to the presence of crystalline Li2CO3 observed by ATR-IR.

[0117] For elemental analysis, samples of the coated particulate material were dissolved in acid using a graphite furnace. The Zn and Nb contents were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) using a Thermo Fisher Scientific iCAP7600DUO. Carbon content was measured using a CS analyzer. Mass percentages represent the average of at least three independent measurements. The mass percentages of Zn and Nb were determined to be 0.077(1) and 0.50(1) mass%, respectively, within the target values ​​of 0.093 and 0.53 mass% (compound Li6ZnNb4O 14 All mass percentage data are relative to the total mass of the core particles. A molar ratio of Nb:Zn approximately equal to 4.57 also resulted in the compound Li6ZnNb4O 14 This deviates from the molar ratio of 4.

[0118] 3. Electrochemical Investigation 1. Preparation of Electrodes The composite for the positive electrode is as follows: E1) Coated particulate matter (according to the invention or not, see point 1 above) or uncoated positive active material E2) Solid electrolyte Li6PS5Cl (LPSCl; NEI Corp.) E3) Super C65 Carbon Black (Timcal) were prepared by mixing in a planetary mill (Fritsch) at 140 rpm for 30 minutes in a weight ratio of 69:30:1.

[0119] The negative electrode composite is carbon-coated Li4Ti5O 12 The composites were prepared by mixing Li6PS5Cl (LTO; NEI Corp.), Li6PS5Cl, and Super C65 carbon black in mass ratios of 30:65:5 (Figures 1-5) and 30:60:10 (Figure 6) in a planetary mill (Fritsch) at 140 rpm for 30 min.

[0120] Solid-state cell assembly and testing procedures All-solid-state cells with different positive electrodes were tested using a customized setup including a polyetheretherketone sleeve and two stainless steel dies. Starting with a separator layer made of 100 mg Li6PS5Cl cold pressed at a uniaxial pressure of 62 MPa, the cells were fabricated in the form of pellet stacks with a diameter of 10 mm. The cells were fabricated by placing 65 mg of anode composite (see above) and 12 mg of cathode composite (see above, ca. 2.9 mAh / cm) on the opposing sides of the cold pressed solid electrolyte. 2 , q th =274mAh / g CAM ) and the stack was pressed at 437 MPa to complete the process.

[0121] Li 2.9-4.3 V at 45 °C while maintaining a uniaxial pressure of 81 MPa + The cells were galvanostatically cycled over a range of voltages versus / Li. The cycle stability test was performed at 1C (1C = 190mA / g CAM ) for 200 cycles. Rate performance tests were performed at 0.1C, 0.2C, 0.5C, and 1C, with two cycles at each C rate. Results are the average of at least three cells.

[0122] Electrochemical impedance spectroscopy measurements were performed on all solid-state cells using a VMP3 impedance analyzer (Bio-Logic Science Instruments Ltd.) at frequencies between 7 MHz and 100 mHz with an amplitude of 10 mV for 200 cycles.

[0123] result Figure 1 shows first cycle charge / discharge curves at 0.1C rate. The top graph is the average charge / discharge curves of three cells according to the invention (having cathodes containing coated particulate matter "Coated inv500"). The bottom graph is the average charge / discharge curves of three comparative cells (having cathodes containing uncoated cathode active material ("Uncoated").

[0124] The cell according to the present invention has a capacity of 180 mAh / g, which is higher than the comparative cell. CAMCompared to 210mAh / g CAM (about 2.2mAh / cm 2 ) reversible specific discharge capacity. The superior reversible specific discharge capacity of the cell according to the invention is presumably made possible by its superior kinetics and coulombic efficiency. The voltage profiles show improved delithiation of the coated active cathode material "coated inv500", resulting in a higher capacity than its uncoated counterpart. The difference in coulombic efficiency (88.6% vs. 78.0% for the inventive and comparative cells, respectively) suggests that a more severe interfacial side reaction (oxidation of the solid electrolyte material) occurred in the case of the uncoated active cathode material. This may explain the significantly reduced overpotential observed in the cell according to the invention, since it is known in the art that adverse reactions between electrode components during cycling can lead to increased resistance.

[0125] FIG. 2 shows the average specific discharge capacity for rates ranging from 0.1 C to 1 C for three cells according to the invention (upper line and dots) and three comparative cells as defined above (lower line and dots). The rate capability of the cells according to the invention was clearly better than that of the comparative cells. At a rate of 1 C (approximately 2 mA / cm 2 ) the cell according to the present invention has a capacity of about 150 mAh / g CAM A specific discharge capacity of about 76 mAh / g was achieved, which corresponds to 71% of the initial capacity at 0.1 C. In contrast, the comparative cell had a specific discharge capacity of about 76 mAh / g. CAM A specific discharge capacity of 1000 μm was obtained, which corresponds to only 42% of the initial capacity. These results highlight the improved charge transfer kinetics through the improved interface between the positive electrode active material and the solid electrolyte in the cell according to the invention.

[0126] Figure 3 shows the average long-term cycling stability of three cells according to the invention (upper graph) and three comparative cells as defined above (lower graph). As expected from the rate performance data shown in Figure 2, the cells according to the invention showed a higher specific capacity. The comparative cells showed a rapid capacity fade in the first 20 cycles, while the capacity fade of the cells according to the invention was found to occur more slowly. In particular, the cells according to the invention retained more than 81% of their initial discharge capacity after 200 cycles, compared to 68% for the comparative cells, despite the much larger cumulative charge exchanged.

[0127] Figure 4 shows the average coulombic efficiency up to cycle number 50 for three cells according to the invention (upper graph) and three comparative cells as defined above (lower graph). The cells according to the invention show higher values ​​overall, the difference being particularly noticeable in the first 20 cycles. This suggests that a stable interface between the active cathode material and the solid electrolyte is formed earlier in the cells according to the invention. Both active cathode materials (uncoated and "coated inv500") also stabilized with a coulombic efficiency of η>99.9% after about 60 cycles.

[0128] Finally, after 200 cycles, a representative cell according to the invention and a representative comparative cell as defined above were examined by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Figure 5 shows the Nyquist plots obtained from EIS measurements of a representative cell in the discharged state. A semiquantitative comparison of the concave semicircles representing the positive electrode interface resistance showed that this contribution was reduced by about a factor of two in the cells according to the invention (smaller semicircles). This finding supports the difference in Coulombic efficiency mentioned above. Cross-sectional SEM images (not shown) showed no signs of major (chemical) mechanical degradation (contact loss, particle fracture, etc.) in either the cells according to the invention or the comparative cells. This suggests that the difference in cycling performance is mainly due to the different extent of (electro)chemical decomposition at the interface between the positive electrode active material and the solid electrolyte.

[0129] FIG. 6 shows six different cathode active materials (for preparation and composition, see Section 1 above for details), i.e. "Not coated" "Coated inv500" "Coated inv300" "Coated non-inv1" "Coated non-inv2" "Coated non-inv3" 4 shows the average long-term cycling stability of cells containing

[0130] The cells were cycled at different charge / discharge rates (as shown in the graph): 1C, 0.2C, 0.5C, 1C (2 charge / discharge cycles each), and 0.2C from cycle 9 onwards.

[0131] The best results were obtained with the cells according to the invention containing the positive electrode active material "coated inv500", while the cells according to the invention containing the positive electrode active material "coated inv300" had a slightly lower specific discharge capacity. It was found that the comparative cells with the uncoated positive electrode active material showed a rapid capacity fade in the first 10 cycles, while the capacity fade of the cells according to the invention occurred more slowly. The comparative cells with positive electrodes containing any of the three coated particulate materials "coated non-inv1", "coated non-inv2" and "coated non-inv3" still had an advantage over the comparative cells with the uncoated positive electrode active material, but nevertheless showed a lower specific discharge capacity and faster capacity fading than the cells according to the invention.

Claims

1. The following ingredients: C1) A plurality of core particles, each core particle having the formula (I): Li １＋ｔ [Co ｘ Mn ｙ Ni ｚ M ｕ ] １－ｔ O ２ (I) (In the formula, 0≦x≦1 0≦y≦1 0≦z≦1 0≦u≦0.15 M, if present, is one or more elements selected from the group consisting of Al, Mg, Ba, B, and transition metals other than Ni, Co, and Mn; x+y+z>0 x + y + z + u = 1 0≦t≦0.2) A plurality of core particles comprising one or more compounds of and C2) a coating disposed on the surface of the core particle, - carbonate anion, - lithium cation, and Niobium and zinc in oxidized form, at least a portion of the niobium being cubic Li with a crystallographic unit cell of the space group Fm-3m ３ NbO ４ Niobium and zinc in oxidized form, present as Including, Preferably, The proportion of Zn is in the range of 0.07% by weight to 0.1% by weight. The proportion of Nb is in the range of 0.4% to 0.6% by mass. the coating comprises a total amount of carbonate anions ranging from 0.08% to 1.62% by weight These are in each case relative to the total mass of the core particles. a coating in which the molar ratio of Li:Nb is in the range of 0.5 to 5.0; 2. A coated particulate material comprising:

2. In said coating, at least a portion of the zinc is in the parent composition Li ３ NbO ４ Or LiNbO ３ 2. The coated particulate material of claim 1, wherein Li and / or Nb are partially replaced by Zn.

3. The coating comprises: - Cubic Li with a crystallographic unit cell of the space group Fm-3m ３ NbO ４ At least one crystalline phase comprising - at least one of a crystalline phase and an amorphous phase containing lithium carbonate 3. The coated particulate material of claim 1 or 2, comprising:

4. the molar ratio Nb:Zn is in the range of 3 to 5; 3. A coated particulate material according to claim 1 or 2.

5. Monoclinic phase Li ６ ZnNb ４ O １４ 3. The coated particulate material according to claim 1 or 2, wherein:

6. 3. The coated particulate material according to claim 1 or 2, wherein the coating comprises carbonate anions in a total amount in the range of 0.122% to 1.22% by weight, preferably ≧0.162% to 0.812% by weight, relative to the total weight of the plurality of core particles.

7. at least a portion of the carbonate ions present in the coating, preferably the total amount of carbonate ions, is present as lithium carbonate; 3. A coated particulate material according to claim 1 or 2.

8. the coating comprises lithium carbonate in a total amount preferably in the range of 0.1% to 2.0% by weight, more preferably in the range of ≧0.15% to 1.5% by weight, and even more preferably in the range of ≧0.15% to 1.0% by weight, relative to the total weight of the plurality of core particles; and / or the Li:Nb molar ratio in said coating is in the range from 0.75 to 4.5, preferably in the range from 1.0 to 4.0; and / or the molar amount of Nb in the coating per gram of core particles is in the range of 6 to 540 μmol / g, preferably in the range of 6 to 270 μmol / g, more preferably in the range of 6 to 108 μmol / g, relative to the total mass of the core particles; 3. A coated particulate material according to claim 1 or 2.

9. 1. An electrode for use in a solid-state lithium-ion electrochemical cell and / or an all-solid-state lithium-ion electrochemical cell, comprising: E1) A total amount of coated particulate matter as defined in claim 1, preferably from 50% to 99% by weight, more preferably from 70% to 97% by weight, relative to the total weight of the electrode; E2) A lithium ion conducting solid electrolyte material in a total amount of preferably 1% to 50% by weight, more preferably 3% to 30% by weight, based on the total weight of the electrode; E3) optionally, electronically conductive carbon, preferably selected from the group consisting of carbon nanofibers, carbon nanotubes, graphene, carbon black, acetylene black, coke, and graphene oxide; E4) Optionally one or more binders , an electrode.

10. 10. The electrode of claim 9, wherein the solid electrolyte E2) is selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxyphosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides.

11. A method for preparing a coated particulate material as defined in claim 1, comprising the steps of: P1) preparing or providing a plurality of core particles C1) as defined in claim 1; P2) preparing or providing a liquid composition comprising a solvent and lithium ions at least partially dissolved in said solvent; P3) preparing or providing a liquid composition comprising a solvent and zinc ions at least partially dissolved in said organic solvent, and a liquid composition comprising an organic solvent and niobium ions at least partially dissolved in said organic solvent, or a liquid composition comprising an organic solvent and zinc ions and niobium ions at least partially dissolved in said organic solvent; P4) contacting the components prepared or provided in steps P1) to P3) with each other to obtain a reaction mixture; P5) removing the solvent from the reaction mixture obtained from step P4) to obtain a solid residue; and P6) heat treatment of the solid residue obtained from step P5) at a temperature ranging from 100° C. to 600° C., preferably from 250° C. to 550° C., to obtain a coated particulate material as defined in claim 1. The method includes:

12. 12. The method of claim 11, In step P2), the liquid composition is prepared by dissolving lithium metal in ethanol. and / or In step P3), one or two liquid compositions are prepared by dissolving niobium ethoxide and zinc acetate in ethanol. and / or the contacting of step P4) comprises (i) the preparation of a dispersion comprising the particles prepared or provided in step P1) and the liquid composition prepared or provided in steps P2) and P3), and (ii) ultrasonic treatment of said dispersion; and / or In step P5), the removal of the solvent comprises the application of a reduced pressure to a standard pressure of 101.325 kPa. and / or in step P6), the heat treatment is carried out in the presence of an oxygen flow, method.

13. 10. An electrochemical cell comprising a coated particulate material as defined in claim 1 or an electrode as defined in claim 9.

14. 14. The electrochemical cell of claim 13 comprising a solid electrolyte selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxyphosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides.

15. 10. Use of the coated particulate material according to claim 1 for preparing an electrode as defined in claim 9.

Images