Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/362—Composites
  • H01M4/366—Composites as layered products
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
  • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/13—Energy storage using capacitors

Definitions

• Electrode material for lithium-ion batteries method of manufacture and use
• the invention relates to an electrode material for lithium-ion batteries, a process for its preparation and its use as an anode material for lithium-ion batteries.
• Electrode material for lithium-ion batteries which can provide good capacity behavior and good numbers of cycles of charge and discharge operations. It is an object of the present invention to provide a method of making a material and the material itself suitable for use as an electrode material having sufficient capacity and cycle stability in a lithium-ion battery.
• an electrode material comprising carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni, wherein the carbon-coated metal oxide particles have carbon in the range of > 0.01% by weight to ⁇ 15% by weight, based on the total weight of the particles.
• the object is further achieved by a method for producing carbon
• step b) oxidation of the pyrolysis products obtained from step a) comprising transition metal and carbon at a temperature in the range of> 300 ° C to ⁇ 825 ° C.
• Carbon coated metal oxide particles are formed, a very good
• the electrodes show a very good capacity behavior at high charging and discharging rates.
• the term “particles” is used synonymously with “particles” in the sense of the present invention.
• the metal oxide particles can have a very thin coating with carbon.
• the layer thickness of the carbon coating is preferably in the range of> 1 nm to ⁇ 50 nm, preferably in the range of> 2 nm to ⁇ 20 nm, preferably in the range of> 4 nm to ⁇ 10 nm.
• a carbon coating of this layer thickness can Significantly improve cell performance, especially at high charge and discharge rates.
• a thin carbon coating of the particles can be a total of low
• Carbon coating correspond.
• the proportion of carbon, based on the total weight of the particles is preferably in the range from 0.1% by weight to ⁇ 11% by weight, preferably in the range from 1% by weight to ⁇ 8% by weight, particularly preferably in the range of> 2 Weight to ⁇ 5 wt.
• To ⁇ 15 wt. Can provide a good specific capacity of an electrode made therefrom. Too much carbon may reduce the specific capacity of the electrode.
• the particles have a size in the nanometer range.
• the particles have a spherical or spherical shape. Spherical or
• Spherical particles have the advantages of being able to have good contact with one another as electrode material. Furthermore, a dense packing is possible.
• the particles, in particular spherical particles have an average
• mean diameter is understood to mean the average value of the diameters of all particles or the arithmetically averaged diameters relative to all particles
• particles of such a size can provide good cyclability of an electrochemical cell
• the particles can also be present as agglomerates
• the particles have a BET surface area in the range of> 1 m / g to ⁇ 20 m 2 / g, preferably in the range of> 2 m 2 / g to ⁇ 10 m 2 / g, particularly preferably in the range of
• the BET surface area may be 3.3 m / g for carbon coated iron (III) oxide particles.
• a BET surface in this range when used as an electrode material, can reduce side reactions at the electrode. In particular, a BET surface in these areas is more advantageous
• the BET surface area can be determined by determining the specific surface area of solids by gas adsorption using the Brunauer-Emmett-Teller (BET) method using the adsorption of nitrogen.
• the particles preferably contain a transition metal selected from the group comprising Ti, V, Mn, Fe, Co and / or Ni, in particular iron.
• Particularly preferred particles are carbon-coated iron oxide particles, in particular carbon-coated iron oxide nanoparticles containing particles with a size in the nanometer range.
• the carbon-coated iron oxide particles may in particular be Fe 2 O 3 particles or Fe 3 O 4 particles.
• Another object of the present invention relates to a process for the preparation of carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni, comprising the following steps: a) pyrolysis of an organometallic Compound with unsubstituted or alkyl-substituted cyclopentadienyl or benzene ligands of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni at a temperature in the range of> 470 ° C to ⁇ 1500 ° C with exclusion of oxygen , and
• step b) oxidation of the pyrolysis products obtained from step a) comprising transition metal and carbon at a temperature in the range of> 300 ° C to ⁇ 825 ° C.
• the method is in particular a method for producing an electrode material, in particular for lithium-based energy stores, comprising carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni.
• high-purity carbon-coated metal oxide particles can be produced by the process.
• a high-quality metal oxide with particle sizes in the nanometer range and simultaneous carbon coating (coating) can be produced.
• the process can achieve very high yields both in the pyrolysis in step a) and in the oxidation according to step b).
• pyrolysis or pyrolytic decomposition in the sense of the present invention is a thermo-chemical cleavage of a particular organometallic compound to understand.
• pyrolysis is used in particular for processes in which carbon remains in addition to the mineral or metallic constituents of the starting compound .Pyrolysis generally takes place under the action of heat and without additionally supplied oxygen.
• an organometallic compound having unsubstituted or alkyl-substituted cyclopentadienyl or benzene ligands is so-called “sandwich” or "half-sandwich” compounds of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni to understand.
• sandwich complexes a central metal atom is sandwiched between two unsubstituted or alkyl-substituted cyclopentadienyl or benzene ligands, while half-sandwich complexes contain only one cyclopentadienyl or benzene ligand.
• bis (benzene) metal complexes is bis (benzene) chromium.
• the sandwich compounds may be present as an uncharged compound or with one or more positive charge and a corresponding counter anion.
• the organometallic compounds may further be present as a single complex or in a polymeric structure.
• organometallic compound with unsubstituted or
• Alkyl-substituted cyclopentadienyl or benzene ligands are selected from the following structural formulas (1) to (4):
• R H or Ci-Cio-alkyl
• M Ti, V, Cr, Mn, Fe, Co or Ni
• n 1 or 2.
• Suitable anions X n ⁇ are for example selected from the group comprising Cl “ , Br “ , F “ Br 3 " , PF 6 “ , ASF ⁇ “ , SbF 6 “ , BF 4 “ and B (C ⁇ H 5 ) 4 " , preferably selected from Cl “ , Br " and F " .
• C 1 -C 10 -alkyl encompasses straight-chain or branched alkyl groups having 1 to 10 carbon atoms, preference being given to C 1 -C 4 -alkyl, in particular methyl and ethyl, with particular preference being given to the pentamethylcyclopentadienyl ligand.
• Examples of so-called half-sandwich complexes are selected from the group comprising (C 5 H 5 ) V (CO) 4 , (C 5 H 5 ) Mn (CO) 3 , (C 5 H 5 ) Co (CO) 2 , ( C 5 H 5 ) Ni (CO),
• metallocenes are understood as meaning organometallic compounds of a transition metal in which the central transition metal atom is arranged between two cyclopentadienyl ligands Sandwich compound A transition metal metallocene selected from the group consisting of Ti, V, Cr, Mn, Fe, Co and / or Ni. Preferred among titanocene, vanadocene, chromocene, manganocene, ferrocene, cobaltacone and nickelocene is ferrocene. Ferrocene is a cheap metallocene. Furthermore, ferrocene-made iron oxide particles are more environmentally friendly than other metals-containing particles.
• the steps of the process can be carried out in the same reactor.
• the process may be carried out in a reactor of a high temperature furnace. This allows a very simple experimental setup.
• organometallic compound in particular a metal ocenpulver can under a
• Inert gas atmosphere for example, Argen at elevated temperature, for example in a range of> 100 ° C to ⁇ 400 ° C, preferably in a range of> 200 ° C to ⁇ 300 ° C, are sublimated into the heating zone of a furnace.
• metallocenes can already sublime completely at these temperatures.
• a furnace for example, Argen at elevated temperature, for example in a range of> 100 ° C to ⁇ 400 ° C, preferably in a range of> 200 ° C to ⁇ 300 ° C.
• Metallocene vapor is passed through a protective or carrier gas such as argon into an oven, for example at a flow rate of the carrier gas in the range of 80 ml / min to 200 ml / min.
• a protective or carrier gas such as argon
• the pyrolysis takes place at a temperature in the range of> 470 ° C to ⁇ 1500 ° C with exclusion of oxygen.
• Metallocenes for example, decompose advantageously as soon as the metallocene vapor has reached the heating zone. Exclusion of oxygen or air can prevent oxidation during pyrolysis.
• the pyrolysis is carried out under a protective gas atmosphere, for example by a noble gas such as argon or nitrogen.
• the pyrolysis is carried out at a temperature in the range of> 470 ° C to ⁇ 1300 ° C, preferably in the range of> 1050 ° C to ⁇ 1100 ° C by.
• the reaction products of pyrolysis are advantageously elemental metal and carbon. These may be in the form of a metal-carbon composite. Becomes For example, if ferrocene is used as the metallocene, an iron-carbon mixture containing 32% by weight of iron and 68% by weight of carbon can be obtained.
• the particle size of the pyrolysis in the nanometer range can be over 95%. Low losses can be caused by the fuming of soot, ie the finest carbon particles.
• Transition metal and carbon oxidized may take place in the same reactor, for example a quartz glass reactor in a high temperature furnace. Pyrolysis and oxidation can be carried out in exchange of the gases used in the same reactor directly after each other and the experimental setup is very easy to implement in an advantageous manner.
• the pyrolysis products comprising transition metal and carbon can be oxidized to carbon-coated metal oxide particles by oxygen as the oxidant.
• Oxygen can be used as pure oxygen, in the form of a mixture with an inert gas or in the form of air. Already lower ones suffice for the oxidation
• oxygen fanwel off.
• the oxygen can also be provided in the form of carbon dioxide, or mixtures containing oxygen and carbon dioxide.
• the oxidation is carried out using oxygen and / or carbon dioxide.
• oxygen or carbon dioxide the use of oxygen or carbon dioxide, the resulting oxide can be influenced. For example, starting from an iron-carbon composite as a pyrolysis product through the
• iron (III) oxide, Fe 2 0 3 Use of oxygen in the oxidation step iron (III) oxide, Fe 2 0 3 , are obtained, while in the use of carbon dioxide iron (II, III) oxide, Fe 3 0 4 , can be obtained.
• the use of pure oxygen, for example with an inert gas has the advantage that impurities can be avoided.
• the oxidation is preferably carried out in a mixture comprising oxygen in the range of> 1 vol to ⁇ 100 vol, preferably in the range of> 20 vol% to ⁇ 50 vol, and an inert gas in the range of> 0 vol % to ⁇ 99 vol., preferably in the range of> 50 vol.% to ⁇ 80 vol., in each case based on the total volume of the gas mixture.
• the inert gas for example, nitrogen or argon is preferable.
• the oxidation may, for example, with a flow rate of oxygen in the range of> 1 ml / min to ⁇ 1000 ml / min, preferably in the range of> 20 ml / min to ⁇ 500 ml / min, preferably in the range of> 80 ml / min to ⁇ 115 ml / min, and / or a flow rate of the inert gas in the range of> 1 ml / min to ⁇ 1000 ml / min, preferably in the range of> 20 ml / min to ⁇ 800 ml / min, preferably in the range of> 320 ml / min to ⁇ 445 ml / min.
• the oxidation can also be carried out in the presence of carbon dioxide. It is of great advantage that you can use C0 2 without inert gas. Carbon dioxide is cheap and well available. However, the oxidation can also be carried out in a mixture
• Carbon dioxide and inert gas are carried out, for example in the range of> 1 vol .-% to ⁇ 100 vol., Preferably in the range of> 20 vol .-% to ⁇ 50 vol., Carbon dioxide and in the range of> 0 vol. % to ⁇ 99 vol., preferably in the range of> 50 vol.% to ⁇ 80 vol., in each case based on the total volume of the gas mixture, of an inert gas.
• the oxidation is carried out at a temperature in the range from> 430 ° C. to ⁇ 700 ° C., preferably in the range from> 430 ° C. to ⁇ 500 ° C.
• the carbon content of the carbon-coated metal oxide particles can be adjusted by the oxidation temperature.
• a temperature in the range of> 430 ° C to ⁇ 700 ° C preferably at a temperature in the range of> 430 ° C to ⁇ 500 ° C, are with
• Carbon coated metal oxide particles having a favorable carbon content available For example, at a temperature of 430 ° C, a carbon content of about 10 percent by weight can be obtained, at a temperature of 500 ° C, a carbon content of about 3 weight percent, while at a temperature of 700 ° C, the carbon content is lower.
• the oxidation may be carried out for a period in the range of> 1 h to ⁇ 20 h, preferably in the range of> 2 h to ⁇ 15 h, preferably in the range of> 5 h to ⁇ 10 h.
• the reaction time may be shorter, the oxidation during a period in the range of> 1 h to ⁇ 10 h, preferably in the range of> 1 h to ⁇ 5 h, preferably in the range of> 2 h to ⁇ 3 h, be carried out.
• the reaction time may be shorter, the oxidation during a period in the range of> 1 h to ⁇ 10 h, preferably in the range of> 1 h to ⁇ 5 h, preferably in the range of> 2 h to ⁇ 3 h, be carried out.
• the method may provide a way to make electrode material.
• the method is a method for producing an electrode material comprising carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni, comprising the following steps:
• step b) oxidation of the pyrolysis products obtained from step a) comprising transition metal and carbon at a temperature in the range of> 300 ° C to ⁇ 825 ° C.
• the carbon-coated metal oxide particles that can be produced by the process can be used, for example, as electrode material for lithium-ion batteries. Through the process, a high quality electrode material with particle sizes in the
• Nanometer range and simultaneous carbon coating (coating) are produced. Particularly in the field of electrochemical energy storage, the particle sizes and the carbon coating are of crucial importance for the performance and cyclability in electrochemical cells such as lithium-ion batteries,
• Another object of the invention relates to carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni obtainable by a process according to the invention.
• Carbon-coated metal oxide particles obtainable by the process according to the invention are characterized as active material in electrodes by a very good cycle stability and a very good
• the carbon-coated metal oxide particles enable cyclization of an electrode producible therefrom without additional additives in the electrolyte
• film-forming additives used in commercial graphite-based cells are particularly advantageous, because this can be a
• solvents that do not form solid electrolyte interphase alone such as propylene carbonate as a solvent for lithium-based energy storage are possible.
• the carbon-coated metal oxide particles enable the
• the metal oxide particles can have a very thin coating with carbon.
• the layer thickness of the carbon coating is in the range of> 1 nm to
• a carbon coating of this layer thickness can significantly improve cell performance, especially at high charge and discharge rates.
• a thin carbon coating of the particles may correspond to a total small amount of carbon based on the total mass of metal oxide and carbon coating.
• the proportion of carbon, based on the total weight of the particles is in the range from 0.01% by weight to ⁇ 15% by weight.
• the proportion of carbon, based on the total weight of the particles is preferably in the range from 0.1% by weight to ⁇ 11% by weight, preferably in the range from 1% by weight to ⁇ 8% by weight, particularly preferably in the range of> 2 Weight to ⁇ 5 wt.
• the particles have a size in the nanometer range.
• the particles have a spherical or spherical shape.
• the particles, in particular spherical particles have an average particle size or mean particle size
• particles of such a size can have a good cyclability of an electrochemical
• the particles can also be present as agglomerates.
• the particles have a BET surface area in the range of> 1 m / g to ⁇ 20 m 2 / g, preferably in the range of> 2 m 2 / g to ⁇ 10 m 2 / g, particularly preferably in the range of> 3 m 2 / g to ⁇ 5 m 2 / g, on.
• the BET surface area may be 3.3 m / g, especially for carbon-coated iron (III) oxide particles.
• a BET surface in this range when used as an electrode material, can reduce side reactions at the electrode. In particular, a BET surface in these areas is more advantageous A way with a high crystallinity associated.
• the BET surface area can be determined by determining the specific surface area of solids by gas adsorption using the Brunauer-Emmett-Teller (BET) method using the adsorption of nitrogen.
• the particles preferably contain a transition metal selected from the group comprising Ti, V, Mn, Fe, Co and / or Ni, in particular iron.
• Particularly preferred particles are carbon-coated iron oxide particles, in particular carbon-coated iron oxide nanoparticles containing particles with a size in the nanometer range.
• the carbon-coated iron oxide particles may in particular be Fe 2 O 3 particles or Fe 3 O 4 particles.
• the invention further relates to the use of carbon-coated metal oxide particles according to the invention or prepared according to the invention of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni
• Electrode material for lithium-based energy storage or supercapacitors especially as anode material.
• Another object of the invention relates to an electrode containing inventive or inventively prepared carbon-coated metal oxide particles of a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni.
• a transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni.
• Active material designated material of an electrode that can absorb and release lithium ions reversibly.
• Metal oxides are so-called “conversion materials” that are reduced to elemental metal and lithium oxide in the first cycle Cycles reversibly oxidize the lithium oxide and metal to lithium metal oxide species and re-reduce them back to metal and lithium oxide. This allows a reversible and stable cycling from the second cycle.
• An electrode comprising carbon-coated according to the invention or produced according to the invention
• Metal oxide particles can advantageously show very good cycle stability, in particular even without additional electrolyte additives.
• the electrodes show a very good cycle stability and a very good capacity behavior, especially at high charge and discharge currents. In particular, it was found that almost no capacity loss occurred from the second cycle.
• a further advantage can be provided by enabling electrode recycling.
• the electrode can be cycled, removed from a cell and installed in a second cell and cycled again with similar capacities.
• an electrode typically still contains binder and conductive carbon. These are usually applied to a metal foil, such as a copper or aluminum foil, as a current conductor. It is advantageous that when using the carbon-coated metal oxide particles aluminum foil can be used as a current collector. This is cheaper than copper foil, which is used in commercial cells for graphite anodes.
• the electrode is a composite electrode comprising carbon-coated metal oxide particles, binders, and optionally conductive carbon according to the present invention.
• Another advantage is that when using the carbon-coated metal oxide particles no additional carbon must be used for the preparation of an electrode.
• the carbon contained in the coating of the particles can provide sufficient electrical conductivity of the electrode Make available.
• it may be provided to add further carbon for the production of an electrode.
• Preferred carbonaceous materials are, for example, carbon black, synthetic or natural graphite, graphene, carbon nanoparticles, fullerenes, or mixtures thereof.
• a usable carbon black is, for example, carbon black.
• Conductive black or conductive carbon black is understood as meaning a carbon black which has small primary particles and widely branched aggregates, and thus enables good electrical conductivity.
• Total weight of carbon-coated metal oxide particles, binder and conductive carbon is preferably in the range of> 50% by weight to ⁇ 99% by weight, preferably in the range of 60% by weight to ⁇ 95% by weight, particularly preferably in the range of> 85% by weight to ⁇ 90% by weight.
• the proportion of added conductive carbon based on the total weight of the composite electrode of carbon-coated metal oxide particles, binder and conductive carbon is preferably in the range of> 0% by weight to ⁇ 10% by weight, preferably in the range of 3% by weight. to ⁇ 10% by weight, particularly preferably in the range of> 5% by weight to ⁇ 8% by weight.
• the composite electrode may comprise binders. Suitable binders are
• PVDF-HFP poly (vinylidene difluoride-hexafluoropropylene) copolymer
• PVDF-HFP polyvinylidene fluoride
• PVDF polyvinylidene fluoride
• SBR styrene-butadiene rubber
• CMC for example, sodium carboxymethylcellulose (Na-CMC), or polytetrafluoroethylene (PTFE) and cellulose, especially natural cellulose.
• PTFE polytetrafluoroethylene
• Carboxymethylcellulose such as sodium carboxymethylcellulose (Na-CMC).
• the composite electrode comprises carboxymethyl cellulose as a binder.
• Carboxymethyl cellulose is more environmentally friendly and less expensive compared to binders used in common commercial batteries. It is advantageous that the electrodes cyclize with good performance using carboxymethylcellulose can be.
• water is a well-suited solvent for carboxymethylcellulose.
• suitable solvents are, for example, N-methylpyrrolidinone (NMP) or acetone.
• NMP N-methylpyrrolidinone
• Carboxymethylcellulose can be used as a cheap and environmentally friendly binder. To Solvation of the binder can be dispensed expensive and harmful solvents.
• the composite electrode based on the
• the dry weight of a mixture of carbon coated metal oxide particles, binder and conductive carbon may include 85 wt% carbon coated metal oxide particles, 10 wt% carbon black and 5 wt% binder, for example carboxymethylcellulose, based on the total weight of the mixture. exhibit.
• the preparation of an electrode may include the steps of mixing the carbon-coated metal oxide particles with carbon black, and mixing the solid mixture with a solvent-dissolved binder in, for example, carboxymethylcellulose dissolved in water and applying the mixture to a conductive substrate and drying the resulting electrodes.
• a lithium-based energy storage device or a supercapacitor comprising an electrode containing inventive or
• Carbon-coated metal oxide particles prepared according to the invention are Carbon-coated metal oxide particles prepared according to the invention.
• Transition metal selected from the group comprising Ti, V, Cr, Mn, Fe, Co and / or Ni.
• Lithium-based energy stores are preferably selected from the group comprising lithium batteries, lithium-ion batteries, lithium-ion batteries, lithium-polymer batteries or lithium-ion capacitors. Preference is given to lithium-ion batteries or lithium-ion batteries.
• Propylene carbonate which is usable without further additives. Furthermore, propylene carbonate is more environmentally friendly, and has a lower flash point compared to other commercial electrolytes, which can provide increased safety of the lithium-based energy storage.
• LiMn 2 0 4 spinel or LiFeP0 4 can phosphates lithium metal oxides or based as L1C0O 2, LiNi0 2, LiNiCo0 2, LiNiCoA10 2 (NCA), LiNiCoMn0 2 in lithium-based energy storage, LFP) can be used.
• Figure 1 shows a transmission electron micrograph with carbon
• FIG. 2 shows a cyclic voltammogram of a composite electrode containing carbon-coated Fe 2 O 3 particles as anode with lithium metal as reference and counterelectrodes.
• FIG. 3 shows the charging and discharging of a composite electrode containing carbon-coated Fe 2 O 3 particles on aluminum foil as a current conductor
• Lithium metal as reference electrode and LiFeP0 4 (LFP) as counterelectrode. Plotted is the charge and discharge capacity Q (left ordinate axis) and efficiency (right ordinate axis) against the number of charge / discharge cycles.
• FIG. 4 shows the capacitance behavior of the composite electrode comprising carbon-coated Fe 2 O 3 particles on aluminum foil at high charging and discharging rates.
• FIG. 5 shows the charging and discharging of a composite electrode containing carbon-coated Fe 2 O 3 particles on copper foil as a current collector with lithium metal as reference electrode and LiFePO 4 (LFP) as counterelectrode.
• the pyrolysis (decomposition) of ferrocene and the oxidation of the pyrolysis products were carried out in a quartz glass reactor in a horizontal high-temperature furnace (P330, Nabertherm).
• the furnace was heated at a heating rate of 10 ° C / minute from room temperature (20 + 2 ° C).
• 7 g of ferrocene (Merck, ferrocene for synthesis) were completely sublimated under an argon protective gas atmosphere at 300 ° C. into the heating zone of the furnace already heated to 1100 ° C., whereby ferrocene vapor was passed into the furnace through a constant argon gas stream.
• the decomposition takes place immediately as soon as the ferrocene vapor has reached the heating zone.
• the experiment was interrupted and the furnace cooled to room temperature under argon protective gas to remove a part of the reaction products and to characterize them.
• the reaction products of pyrolysis were elemental iron and carbon, which were in the form of a metal-carbon composite.
• the iron carbon mixture contained 32 percent by weight of iron and 68 percent by weight of carbon, based on the total weight.
• the yield of pyrolysis was over 95% based on metal and carbon.
• an air flow of 20% by volume of oxygen gas and 80% by volume of nitrogen gas was generated by passing a flow of 114 ml of oxygen and 455 ml of nitrogen per minute through the furnace.
• the samples were heated from room temperature to the target temperature of 700 ° C at a heating rate of 5 ° C / min. The temperature was held constant for 2 hours before allowing the oven to cool to room temperature.
• FIG. 1 shows a
• the particle size of the carbon-coated iron oxide particles was in the range between 10 nm and 150 nm
• Quartz glass reactor in a horizontal high-temperature furnace (P330, Nabertherm).
• a stream of 100% by volume carbon dioxide gas was produced by passing a flow of 84 ml per minute through the furnace.
• the samples were heated from room temperature to a temperature of 825 ° C at a heating rate of 5 ° C / min. The temperature was held constant for 20 hours before allowing the oven to cool to room temperature.
• Electrodes were prepared according to Example 1 with carbon-coated Fe 2 0 3 particles with conductive carbon and binder in one
• CMC carboxymethylcellulose
• Example 4 The coated film was dried at 80 ° C overnight in an oven. Subsequently, round electrodes with a diameter of 12 mm, or an area of 1.13 cm, were punched out and dried in vacuum ovens at 180 ° C under vacuum for 24 hours. The surface loading was in each case 1.5 mg cm ". The determination of the loading surface by weighing the pure film and the punched-out electrodes.
• Example 4 The determination of the loading surface by weighing the pure film and the punched-out electrodes.
• the experiment was carried out with a composite electrode containing at an oxidation temperature of 700 ° C according to Example 1 prepared with carbon-coated Fe 2 0 3 particles on aluminum foil as a current collector.
• Electrochemical analysis of the electrode prepared according to Example 3 was carried out in three-electrode Swagelok TM cells with lithium metal foils ("battery grade" purity, Chemetall) as counter and reference electrodes
• the cells were assembled in a glovebox filled with argon in an inert gas atmosphere an oxygen and
• Cycling was conducted for 5 cycles at a scan rate of 50 ⁇ V / s in the range of 0.6V to 3.0V versus lithium.
• Iron oxide as well as other metal oxides, is a so-called "conversion material.”
• Figure 2 shows from the signal at about 0.8 V versus lithium that the iron oxide was reduced to elemental iron and lithium oxide in the first cycle (1) Cycles are oxidized lithium oxide and iron reversibly to lithium iron oxide and the same back to iron and lithium oxide back reduced.
• the experiment was carried out with a composite electrode containing at an oxidation temperature of 700 ° C according to Example 1 prepared with carbon-coated Fe 2 0 3 particles on aluminum foil as a current collector.
• the round electrode had a diameter of 12 mm, respectively, an area of 1.13 cm 2, and the area loading was 1.5 mg cm - " 2.
• the charging and discharging of the composite electrode was carried out in a three-electrode
• Swagelok TM cell Lithium metal foil (“battery grade” purity, chemetall) was used as the reference electrode and LiFeP0 4 (south chemistry) as the counterelectrode As the electrolyte, 1 M LiPF 6 (Sigma-Aldrich, "99.99% purity” battery grade) was dissolved as the conducting salt in propylene carbonate (battery grade , 99.99% purity, UBE).
• the charge and discharge rate was 126 mA / g corresponding to C / 8 at 1007 mAh / g of theoretical capacity between 0.6 V and 3.0 V versus lithium, the capacity being calculated on the mass of the iron oxide.
• Figure 3 shows the results of the galvanostatic charge / discharge tests, in which the charge and discharge capacity (Q) on the left ordinate axis and the efficiency on the right ordinate axis against the number of charge / discharge cycles are plotted.
• Q charge and discharge capacity
• the electrode exhibited a capacitance of about 350 mAh / g at 5C. This corresponds to a higher capacity compared to the capacity of IC graphite cycled electrodes. The electrodes thus showed a very good capacity behavior at high charging and discharging rates.
• Copper foil performed as a current conductor.
• the round electrode had a diameter of
• the electrode was charged and discharged in a three-electrode Swagelok TM cell.
• Lithium metal foil (“battery grade” purity, Chemetall) was used as reference electrode and LiFeP0 4 (LFP) (south chemistry) as counterelectrode as electrolyte was dissolved 1 M LiPF 6 (Sigma-Aldrich, "99,99% purity” battery grade) as conducting salt in
• Propylene carbonate (battery grade, 99.99% purity, OBE) used.
• the charge and discharge rate was 126 mA / g, corresponding to C / 8 at 1007 mAh / g of theoretical capacity between 0.08 V and 3.0 V versus lithium, the capacity being calculated to the mass of the iron oxide.
• FIG. 5 shows the charge and discharge capacity (Q) of the electrode on the left
• Composite electrodes containing at oxidation temperatures of 430 ° C, 500 ° C and 600 ° C according to Example 1 prepared with carbon-coated Fe 2 0 3 particles carried out on aluminum foil as a current collector. The charging and discharging of the electrodes was carried out as described in Example 4. It was found that the particles produced at oxidation temperatures of 430 ° C, 500 ° C and 600 ° C also enabled a reversible and stable cyclization. Likewise it could be determined that a cyclization without additional additives in
• Example 6 The electrochemical investigations described in Example 6 were carried out with prepared according to Example 3 composite electrodes containing at oxidation temperatures of 430 ° C, 500 ° C and 600 ° C according to Example 1 prepared with carbon coated Fe 2 0 3 particles on copper foil as a current collector.
• Electrode material for lithium-ion batteries or lithium-ion capacitors are suitable.

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• 2012
  • 2012-01-31 DE DE102012100789A patent/DE102012100789A1/de not_active Withdrawn
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