Classifications

• • 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
  • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• • 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
  • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/45—Phosphates containing plural metal, or metal and ammonium
• • 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
• • 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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• • 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
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/624—Electric conductive fillers
  • H01M4/625—Carbon or graphite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • 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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• • 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

Definitions

• the invention relates to a method for manufacturing nanoparticles of olivine phosphate LiMPO. sub.4, where M is Mn, Fe, Co, Ni, V, Cu, Ti and mix of them.
• This method enables the production of a material with an olivine structure of excellent crystallinity and high purity.
• the method utilises a lower processing temperature than is required to produce similar materials via conventional methods.
• Insertion compounds are those that act as a solid host for the reversible insertion of guest atoms.
• Cathode materials that will reversibly intercalate lithium have been studied extensively in recent years for use as electrode materials in advanced high energy density batteries and they form the cornerstone of the emerging lithium-ion battery industry.
• Lithium-ion batteries have the greatest gravimetric (Wh/kg) and volumetric (Wh/L) energy densities of currently available conventional rechargeable systems (i.e., NiCd, NiMH, or lead acid batteries) and represent a preferred rechargeable power source for many consumer electronics applications. Additionally, lithium ion batteries operate around 3.6 volts enabling a single cell to operate in the correct voltage window for many consumer electronic applications.
• Lithium ion batteries use two different insertion compounds: for the active cathode and for the anode materials.
• lithium is extracted from the cathode material while lithium is concurrently inserted into the anode on charge of the battery.
• Lithium atoms travel, or "rock", from one electrode to the other in the form of ions dissolved in an electrolyte. The associated electrons travel in the circuit external to the battery.
• Layered rock-salt compounds such as LiCoO.sub.2 and LiNiO.sub.2 (1) are proven cathode materials. Nonetheless, Co and Ni compounds have economic and environmental problems that leave the door open for alternative materials.
• LiMn.sub.2 O.sub.4 is a particularly attractive cathode material candidate because manganese is environmentally benign and significantly cheaper than cobalt and/or nickel.
• LiMn.sub.2 O.sub.4 refers to a stoichiometric lithium manganese oxide with a spinel crystal structure.
• a spinel LiMn.sub.2 O.sub.4 intercalation cathode is the subject of intense development work (2), although it is not without faults.
• the specific capacity obtained (120 mAh/g) is 15-30% lower than Li(Co,Ni)O.sub.2 cathodes, and unmodified LiMn.sub.2 O.sub.4 exhibits an unacceptably high capacity fade.
• Lithium iron phosphate LiFePO.sub.4 has established its position as a potential next generation cathode material. LiFePO.sub.4 has advantages in terms of material cost, chemical stability and safety.
• LiFePO.sub.4 has a significantly lower voltage (3.45V versus Li/Li.sup.+) when compared to the (3.9 V versus Li/Li.sup.+) in the standard LiCoO.sub.2 based lithium ion batteries and this lowers the energy available for the LiFePO.sub.4 system.
• LiFePO.sub.4 has low electronic conductivity which leads to initial capacity loss and poor rate capability associated with diffusion-controlled kinetics of the electrochemical process. Morphological modification at the nano-scale level appears to be the best tool to control these undesired phenomena.
• LiMnPO. sub.4 is an insulator with ca. 2 eV spin exchange band gap and this significantly lowers the electrochemical activity compared to LiFePO.sub.4 which is a semiconductor with ca. 0.3eV crystal field band gap. Furthermore the two-phase Mn.sup.3+/Mn.sup.2+ redox character also prohibits the introduction of mobile electrons or holes into the band.
• a new method to obtain nanoparticles has been conducted via a polyol process (9).
• Polyols are considered to exert reducing power at their relatively high boiling points and well defined nanoparticles are obtained (10).
• the polyol process has been well adopted to the preparation of divided powders of metals (11, 12) and binary alloys (13, 14).
• the polyol process consists of the reduction in a liquid alcoholic medium of metallic oxides, hydroxides, alkoxides and salts.
• LiMPO.sub.4 phospho-olivine compounds
• the primary object of the invention is to obtain LiMnPO.sub.4 of an excellent crystallinity and a high purity via a "chimieless" reaction and low sintering temperatures.
• the invention is a method for manufacturing lithium metal phosphate (LiMPO.sub.4) where M is Mn, Fe, Co, Ni, V, Cu....
• the primary object of the invention is to describe a synthetic preparation method. More particularly, the primary object of the present invention is to provide a "polyol" process route resulting in a pure well- crystallised phase of LiMPO.sub.4.
• the electrochemical properties of the material as a positive electrode in Lithium ion battery are improved.
• the third object of the invention is to describe an electrode preparation of the lithium metal phosphate / carbon composite. This process is very important to reach the correct electrochemical performances.
• FIG. 1 shows the general flow chart for the preparation of the olivine Lithium Metal Phosphate (LiMPO.sub.4) disclosed in the present invention.
• FIG. 2 shows X-ray diffraction pattern of the Lithiophilite Lithium Manganese Phosphate (LiMnPO.sub.4) disclosed in the present invention.
• FIG. 3 shows the SEM pictures of a LiMnPO.sub.4 prepared by a "polyol" process.
• FIG. 4 shows specific capacity during discharge for LiMnPOsub.4 prepared by "polyol” process at C /10 rates.
• lithium metal phosphate where metal is manganese, iron, cobalt, copper, nickel, vanadium, titanium and mix of them
• LiMPO. sub.4 a method for manufacturing LiMPO. sub.4 according to the invention will be described.
• the present invention discloses a type of synthesis that turned out to be well-suited for the preparation of spherical oxide particles of 20-150 nm in size is so-called "polyol" method.
• the alcohol itself acts as a stabilizer, limiting particle growth and prohibiting agglomeration.
• the high boiling point of the alcohol means that temperature can be applied (>150°C), that result in highly crystalline oxides.
• the method for manufacturing LiMPO. sub.4 according to the invention is a method of obtaining LiMPO.sub.4 by carrying out the steps of dissolution, hydrolysis, drying and eventually calcination.
• the present invention discloses a "polyol” method to prepare lithium metal phosphates.
• Polyol-mediated preparation is carried out by dissolving a suited metal (Mn, Fe, Co, Cu, Ni, V...) precursors (e.g. acetates, alcoholates, oxides, alkoxides) in a suited solvent (e.g. ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol etc.)
• the polyol acts first as a solvent for the starting inorganic precursors due to the rather dielectric constant of these organic media.
• salts such as manganese acetates, cobalt acetates, iron acetates hydrate are soluble to such an extent that a complete dissolution is observed as the first step of the reaction.
• the molar ratio metal salts/polyol can be varied from 0.01 to 0.15. In some cases, a few cubic centimetres of an aqueous solution can be added to increase the solubility of the salts. The solution is heated from 100 to 150 0 C (depending of the solvent) for 1 to 3 hours to complete the dissolution. 2. Hydrolysis process
• the polyol also acts as solvent with a chelating effect which avoids agglomeration of particles during the preparation.
• Stoichiometric amounts of suitable lithium salts e.g. lithium acetate hydrate
• phosphate salts e.g. ammonium dihydrogeno phosphate
• the solution was added to the polyol media.
• the water acts as a hydrolysis agent.
• the emerging suspension was heated for several hours up to 170 - 200 0 C under stirring. A dehydration occurred at high temperature.
• an acid can also be used to hydrolyse the solution.
• the solid material was separated from the suspension by centrifugation and washed twice with ethanol.
• the "as synthesized" sample was dried at 80 0 C for one day under air.
• the material shows the correct olivine structure after this treatment.
• the specific surface area is about 30 to 70 m.sub.2/g (particles size is about 60 to 25nm)
• the material can be heated at different temperatures (300 - 500 0 C) from 30 minutes to 1 hour in air.
• the resulting powder was ground in a mortar and characterised by X-ray diffraction study.
• the specific surface area is approximately/ in the range 20 to 50 m.sub.2/g (particle size is approximately/ in the range 90 to 35 nm).
• the method for manufacturing the positive electrode active material according to the invention is characterized by blending a conductive agent with the LiMPO.sub.4 obtained according to the above method for manufacturing the LiMPO.sub.4 and LiMPO.sub.4 used in the invention, being obtained according to a manufacturing method described in the "A. Method for manufacturing LiMPO. sub.4", is omitted from describing here.
• the conductive agent used in the invention is not particularly restricted.
• graphite or carbon black such as acetylene black can be cited.
• the conductive agent is added in the range of 5 to 25 parts by weight, preferably in the range of 10 to 20 parts by weight to 100 parts by weight of LiMPO. sub.4.
• an amount of the conductive agent is less than necessary, the electrical conductivity may not be sufficiently improved, and, when it is more than necessary, since an amount of LiMPO. sub.4 becomes relatively less, the performances as the positive electrode active material may be deteriorated.
• a method of blending the LiMPO.sub.4 and the conductive agent is not particularly restricted.
• the physical blending is preferable and the mechanical blending is particularly preferable.
• a ball mill pulverizing method or the like can be cited.
• applications of the positive electrode active material obtained according to the invention are not particularly restricted. However, it can be used in, for instance, lithium secondary batteries.
• the present invention discloses improved electrochemical performances of LiMPO.sub.4/ carbon composite.
• This composite was obtained by high energy milling of LiMPO.sub.4 with acetylene black in a stainless steel container using a planetary ball mill for several hours.
• the present invention also discloses electrode preparation of LiMPO. sub.4/C composite to improve electrochemical performances.
• Electrode of LiMPO. sub4/C active material was prepared by mixing of the active material (composite) with a carbon black and a binder in N- methyl-2-pyrrolidinon. The slurry was then coated on an aluminium foil, serving as the current collector. The N-methyl-2-pyrrolidinon was subsequently evaporated in air on titanium hot plate.
• X-ray pattern of this material indicates a pure crystallized phase of lithium manganese phosphate (LiMnPO.sub.4).
• the particle sizes of the material were included in the range 90- 20 nm.
• the powder of LiMnPO. sub.4 was placed in a 250 mL stainless steel container and ball milled with a planetary ball mill using 9 stainless steel balls of 20mm diameter for one hour.
• 20% in weight of acetylene black was added to the milled LiMnPO. sub.4 and ball milled again for 3 hours.
• a composite of LiMnPO.sub.4/C was then obtained.
• a positive electrode composition of LiMnPO.sub4/C active material was prepared by mixing of the active material (composite) with a carbon black (C55 from Shawinigan) and a binder (polyvinylidene difluoride -PVDF) with the mass ratio (90 : 5 : 5), in N-methyl-2- pyrrolidinon.
• the slurry was then coated on an aluminium foil, serving as the current collector.
• the N-methyl-2-pyrrolidinon was subsequently evaporated in air at 100°C for 1 hour and 120°C for 30 minutes on titanium hot plate.
• the electrode was then dry at 160°C overnight under vacuum.
• the positive electrode of example 3 was tested in standard laboratory Swagelok test cells versus Li metal. Microporous Celgard membrane served as separator.
• the electrolyte was made of IM of LiPF.sub.6 dissolved in a 1:1:3 by volume mixture of dried and purified propylene carbonate (PC), ethylene carbonate (EC) and dimethyl carbonate (DMC).
• PC propylene carbonate
• EC ethylene carbonate
• DMC dimethyl carbonate
• the battery prepared above was charged under a current density of 0.03 mA/cm.sup.2 until a termination voltage of 4.7 volt was reached. Then the charged battery was discharged at a current density of 0.03 mA/cm.sup.2 until a termination voltage of 2.3 volt was reached.
• X-ray pattern of this material indicates a pure phase of lithium cobalt phosphate (LiCoPO.sub.4).
• the particle sizes of the material were included in the range 90- 20 nm.
• X-ray pattern of this material indicates a pure phase of lithium iron phosphate (LiFePO.sub.4).
• the particle sizes of the material were included in the range 90- 20 nm.
• X-ray pattern of this material indicates a pure crystallized phase of lithium manganese phosphate (LiMnPO.sub.4).
• the particle sizes of the material were included in the range 90- 40 nm.
• Example 9 The synthesis of nanoparticles of LiMnPO.sub.4 was performed according to those in Example 1 characterized in that the dried powder at 80 0 C is already crystallised and no calcination step was applied. The particle sizes of the material were included in the range 50- 20 nm.

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• 2006
  • 2006-04-06 JP JP2009503671A patent/JP5174803B2/ja not_active Expired - Fee Related
  • 2006-04-06 CN CN200680054126.0A patent/CN101415640B/zh not_active Expired - Fee Related
  • 2006-04-06 WO PCT/IB2006/051061 patent/WO2007113624A1/en not_active Ceased
  • 2006-04-06 EP EP06727848A patent/EP2004548A1/en not_active Withdrawn
  • 2006-04-06 KR KR1020087023271A patent/KR101331457B1/ko not_active Expired - Fee Related
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