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EP-4441807-B1 - COATED PARTICULATE MATERIAL FOR USE IN AN ELECTRODE OF AN ELECTROCHEMICAL CELL

EP4441807B1EP 4441807 B1EP4441807 B1EP 4441807B1EP-4441807-B1

Inventors

  • KITSCHE, David
  • STRAUSS, Florian
  • BREZESINSKI, TORSTEN
  • KONDRAKOV, Aleksandr

Dates

Publication Date
20260513
Application Date
20221201

Claims (15)

  1. A coated particulate material, comprising C1) a plurality of core particles, each core particle comprising one or more compounds of formula (I): Li 1+t [Co x Mn y Ni z M u ] 1-t O 2 (I) wherein 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 and C2) disposed on the surfaces of the core particles, a coating comprising - carbonate anions, - lithium cations, and - niobium and zinc in oxidized form, wherein at least a part of the niobium is present as cubic Li 3 NbO 4 having a crystallographic unit cell of space group Fm-3m wherein - the fraction of Zn is in the range of from 0.07 mass-% to 0.1 mass-% - the fraction of Nb is in the range of from 0.4 mass-% to 0.6 mass-% - the coating comprises carbonate anions in a total amount in the range of from 0.08 mass-% to 1.62 mass-% in each case relative to the total mass of the plurality of core particles - the molar ratio of Li:Nb in the coating is in the range of from 0.5 to 5.0.
  2. Coated particulate material according to claim 1, wherein in the coating at least a part of the zinc is present in a compound having a composition derived from the parent composition Li 3 NbO 4 or LiNbO 3 wherein Li and/or Nb are partially substituted by Zn.
  3. Coated particulate material according to claim 1 or 2, wherein the coating comprises - at least one crystalline phase comprising cubic Li 3 NbO 4 having a crystallographic unit cell of space group Fm-3m - at least one of a crystalline phase and an amorphous phase comprising lithium carbonate.
  4. Coated particulate material according to any preceding claim, wherein - the molar ratio Nb:Zn is in the range of from 3 to 5.
  5. Coated particulate material according to any preceding claim, wherein the monoclinic phase Li 6 ZnNb 4 O 14 is not present in the coated particulate material.
  6. Coated particulate material according to any preceding claim, wherein the coating comprises carbonate anions in a total amount in the range of from 0.122 mass-% to 1.22 mass-%, preferably of from ≥ 0.162 mass-% to 0.812 mass-% relative to the total mass of the plurality of core particles.
  7. Coated particulate material according to any preceding claim, wherein - at least a part of the carbonate ions, preferably the total amount of carbonate ions in the coating is present as lithium carbonate.
  8. Coated particulate material according to any preceding claim, wherein - the coating comprises lithium carbonate, preferably in a total amount in the range of from 0.1 mass-% to 2.0 mass-%, more preferably of from ≥ 0.15 mass-% to 1.5 mass-%, yet more preferably of from ≥ 0.15 mass-% to 1.0 mass-%, relative to the total mass of the plurality of core particles; and/or - the molar ratio of Li:Nb in the coating is in the range of from 0.75 to 4.5, preferably of from 1.0 to 4.0, and/or - the molar amount of Nb in the coating per g of the plurality of core particles is in the range of from 6 to 540 µmol/g, preferably of from 6 to 270 µmol/g, more preferably of from 6 to 108 µmol/g, relative to the total mass of the plurality of core particles.
  9. Electrode for use in a solid-state lithium-ion electrochemical cell and/or in an all-solid-state lithium-ion electrochemical cell, comprising E1) a coated particulate material as defined in any of claims 1 to 8, preferably in a total amount of from 50 mass-% to 99 mass-%, more preferably of from 70 mass-% to 97 mass-%, relative to the total mass of the electrode, E2) a lithium ion-conducting solid electrolyte material, preferably in a total amount of from 1 mass-% to 50 mass-%, more preferably of from 3 mass-% to 30 mass-%, relative to the total mass of the electrode, E3) optionally electron-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 binding agents.
  10. Electrode according to claim 9, wherein said 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. Process for preparing a coated particulate material as defined in any of claims 1 to 8, comprising the steps 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, at least partially dissolved in said solvent, lithium ions, P3) preparing or providing a liquid composition comprising a solvent and, at least partially dissolved in said organic solvent, zinc ions, and a liquid composition comprising an organic solvent and, at least partially dissolved in said organic solvent, niobium ions, or a liquid composition comprising an organic solvent and, at least partially dissolved in said organic solvent, zinc ions and niobium ions, P4) contacting the components prepared or provided in steps P1) to P3) with each other, so that a reaction mixture results, P5) removing the solvents from the reaction mixture resulting from step P4), so that a solid residue results, and P6) heat-treating the solid residue resulting from step P5) at a temperature in the range of from 100 °C to 600 °C, preferably of from 250 °C to 550 °C, so that a coated particulate material as defined in any of claims 1 to 8 results.
  12. Process according to claim 11, wherein - 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 - step P4) contacting comprises (i) preparation of a dispersion comprising the particles prepared or provided in step P1) and the liquid compositions prepared or provided in steps P2) and P3), and (ii) ultrasonic treatment of said dispersion and/or - in step P5) removal of the solvents comprises application of reduced pressure relative to standard pressure 101.325 kPa and/or - in step P6) the heat-treating is carried out in the presence of an oxygen flow.
  13. An electrochemical cell comprising a coated particulate material as defined in any of claims 1 to 8 or an electrode as defined in any of claims 9 and 10.
  14. Electrochemical cell according to claim 13, wherein said electrochemical cell comprises a solid electrolyte selected from the group consisting of lithium-containing sulfides, lithium-containing oxysulfides, lithium-containing oxy-phosphates, lithium-containing thiophosphates, lithium argyrodites, lithium transition metal halides, and lithium-containing oxyphosphonitrides.
  15. Use of a coated particulate material according to any of claims 1 to 8 for preparing an electrode as defined in any of claims 9 and 10.

Description

Described are a coated particulate material for use in an electrode of an electrochemical cell and a process for preparing said coated particulate material, an electrode comprising said coated particulate material, an electrochemical cell comprising said coated particulate material, and a use of said coated particulate material for preparing an electrode for use in an electrochemical cell. High energy density all-solid-state batteries may be realized through application of electrode active materials having a redox potential of 4 V or more vs. Li+/Li (cathode active material of the "4 V class"), so that a high cell voltage is obtainable. However, such cathode active materials may be incompatible with typical lithium ion-conducting solid electrolyte materials used for all-solid-state batteries, because the cathode active material may act as an oxidizing agent towards the solid electrolyte present in the cathode and/or in the separator layer. To solve this problem, it was proposed to apply a coating to the cathode active material which serves as a protection layer protecting the solid electrolyte from being oxidized by the cathode active material, without inhibiting the transfer of lithium ions between the cathode active material and the solid electrolyte. WO 2020/249659 A1 discloses a coated particulate material for use as electrode active material in an electrode and/or in a solid-state lithium-ion electrochemical cell, said coted particulate material comprising a plurality of core particles, each core particle comprising at least one nickel-containing complex layered oxide, and disposed on the surfaces of the core particles, a coating comprising carbonate ions, lithium and at least one further element. WO 2020/249659 A1also discloses an electrode for use in a solid-state or lithium-ion electrochemical cell and a respective electrochemical cell, said electrode comprising said coated particulate material. Said coating comprises carbonate anions, lithium and at least one member of the group consisting of aluminium, boron, niobium, phosphorus, silicon, tantalum, titanium, zinc, zirconium and mixtures thereof. The at least one member of the group consisting of aluminum, boron, niobium, phosphorus, silicon, tantalum, titanium, zinc, zirconium and mixtures thereof may be present as a part of one or more compounds selected from the group consisting of LiNbO3, Li2ZrO3, LiTaO3, Li3PO4, Li3BO3, LiAlO2, Li6ZnNb4O14 and Zn3(PO4)2. No example is provided for a coating comprising Li6ZnNb4O14. Moreover, no example is provided how to obtain a coating wherein both, zinc and niobium, are present. In contrast, all exemplary coatings disclosed in WO 2020/249659 A1 contain niobium, and no further member of the group consisting of aluminium, boron, phosphorus, silicon, tantalum, titanium, zinc, and zirconium is present. Related art is also US 2020/0388841 A1. Although application of a coating containing Li3NbO4 or LiNbO3 to the cathode active material was found to have an advantageous effect on the initial discharge capacity as well as on the cycling performance and stability, further improvement, i.e. increase of the initial capacity as well as reduction of the capacity loss during cycling, is desirable. According to a first aspect, there is provided a coated particulate material, comprising or consisting of C1) a plurality of core particles, each core particle comprising or consisting of one or more compounds of formula (I):         Li1+t[CoxMnyNizMu]1-tO2     (I) wherein 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 andC2) disposed on the surfaces of the core particles, a coating comprising carbonate anions,lithium cations, andniobium and zinc in oxidized form, wherein at least a part of the niobium is present as cubic Li3NbO4 having a crystallographic unit cell of space group Fm-3m. wherein preferably the fraction of Zn is in the range of from 0.07 mass-% to 0.1 mass-%the fraction of Nb is in the range of from 0.4 mass-% to 0.6 mass-%the coating comprises carbonate anions in a total amount in the range of from 0.08 mass-% to 1.62 mass-% in each case relative to the total mass of the plurality of core particles the molar ratio of Li:Nb in the coating is in the range of from 0.5 to 5.0. Compounds of formula (I) are capable of acting as a cathode active material in an electrochemical cell. In the context of the present disclosure, the electrode of an electrochemical cell where during discharging of the cell a net positive charge occurs is called the cathode, and the component of the cathode by reduction of which said net positive charge is generated is referred to as a "cathode active material". Preferably, each core particle C1) consists of at least one compound of formula (I). Preferred cathode active materials are those having a redox potential of 4 V or more vs. Li+/Li (cathode a