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
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
  • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• • 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
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G37/00—Compounds of chromium
  • C01G37/006—Compounds containing chromium, with or without oxygen or hydrogen, and containing two or more other elements
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G45/00—Compounds of manganese
  • C01G45/12—Complex oxides containing manganese and at least one other metal element
  • C01G45/1221—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof
  • C01G45/1235—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof of the type (Mn2O4)2-, e.g. Li2Mn2O4 or Li2(MxMn2-x)O4
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G53/00—Compounds of nickel
  • C01G53/40—Complex oxides containing nickel and at least one other metal element
  • C01G53/42—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2
  • C01G53/44—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese
  • C01G53/52—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese of the type (Mn2O4)2-, e.g. Li2(NixMn2-x)O4 or Li2(MyNixMn2-x-y)O4
• • 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
  • H01M4/48—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
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/50—Solid solutions
  • C01P2002/52—Solid solutions containing elements as dopants
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
  • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
  • C01P2002/76—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by a space-group or by other symmetry indications
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
  • C01P2002/77—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by unit-cell parameters, atom positions or structure diagrams
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/40—Electric properties
• • 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
• • 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
  • H01M4/04—Processes of manufacture in general
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S502/00—Catalyst, solid sorbent, or support therefor: product or process of making
  • Y10S502/524—Spinel
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S502/00—Catalyst, solid sorbent, or support therefor: product or process of making
  • Y10S502/525—Perovskite

Definitions

• This invention relates to preparing compounds useful as electrode compositions for lithium- ion batteries .
• Lithium-ion batteries typically feature a pair of electrodes, at least one of which contains lithium in the form of a lithium-transition metal oxide. These batteries offer the advantages of high energy storage capacity and rechargeability . For optimum performance, it is desirable to maximize electrode capacity between cutoff voltages in the range of about 2.5V to about 4.2V versus lithium metal.
• the invention features a compound having the formula Li q Cr x . y Ni y Mn 2 _ x 0 4+z where q >
• the invention also features an electrode composition that includes this compound.
• an electrode composition that includes this compound.
• the invention features a process for preparing a compound that includes the steps of (a) preparing a solution that includes (i) a chromium source, (ii) a nickel source, (iii) a manganese source, (iv) a lithium source, and (v) an oxygen source, the relative amounts of each of the sources being selected to yield, following step (c) , a compound having the formula Li q Cr x _ y Ni y Mn 2 . x 0 4+z where q >
• the gel is heated at a temperature less than about 900°C, preferably no greater than about 800°C, and more preferably between about
• the solution preferably is an aqueous solution.
• the gel is preferably formed by treating the solution with ammonium hydroxide.
• the chromium, nickel, manganese, lithium, and oxygen sources may be in the form of four separate materials, or in the form of a material that combines two or more of these elements.
• the chromium source preferably is a compound consisting essentially of chromium and at least one additional element selected from the group consisting of oxygen, nitrogen, carbon, and hydrogen.
• examples of such chromium sources include chromium oxide and chromium salts such as chromium nitrate. Chromium nitrate acts as a source of both chromium and oxygen.
• the nickel source preferably is a compound consisting essentially of nickel and at least one additional element selected from the group consisting of oxygen, nitrogen, carbon, and hydrogen.
• nickel sources include nickel oxide and nickel salts such as nickel nitrate.
• the manganese source preferably is a compound consisting essentially of manganese and at least one additional element selected from the group consisting of oxygen, nitrogen, carbon, and hydrogen.
• manganese carbonate and manganese salts such as manganese acetate. Similar to the case of chromium nitrate, manganese acetate acts as a source of both manganese and oxygen.
• the lithium source preferably is a compound consisting essentially of lithium and at least one additional element selected from the group consisting of oxygen, nitrogen, carbon, and hydrogen.
• An example is a lithium salt such as lithium hydroxide, a material which acts as a source of both lithium and oxygen.
• the chromium, nickel, manganese, lithium, and oxygen sources are selected to yield, following step (c) , a compound having the formula Li q Cr x _ y Ni y Mn 2 _ x 0 4+z where q > 2 , 1.0 ⁇ x
• the chromium, nickel, manganese, lithium, and oxygen sources are selected to yield, following step (c) , a compound having the formula Li q Cr x _ y Ni y Mn 2 . x 0 4+z where q >
• the chromium, nickel, manganese, lithium, and oxygen sources are selected to yield, following step (c) , a compound having the formula Li q Cr x _ y ⁇ i y Mn 2 . x 0 4+z where q > 2 , x >
• the invention features a process for preparing a compound that includes the steps of (a) combining (i) a chromium source, (ii) a nickel source, (iii) a manganese source, (iv) a lithium source, and (v) an oxygen source, the relative amounts of each of the sources being selected to yield, following step (c) , a compound having the formula
• the homogenous powder is heated at a temperature less than about 1000°C, preferably no greater than about 900°C, and more preferably between about 700°C and about 900°C.
• the invention features a lithium ion battery that includes: (a) a first electrode that includes a compound having the formula Li q Cr x _ y Ni y Mn 2 . x 0 4+z where q ⁇ O, 1.0 ⁇ x ⁇ 1.25, 0 ⁇ y ⁇ 0.9, and z ⁇ 0, (b) a second electrode; and (c) an electrolyte, in which the first electrode has a reversible specific capacity of at least 100 mAh/g in the range 2.5V - 4.2V vs. lithium metal when discharged at a rate corresponding to full discharge in 10 hours or less.
• the invention provides compounds useful as electrode compositions (e.g., cathode compositions) for lithium-ion batteries.
• the electrode compositions exhibit good performance, as measured, e.g., by reversible and irreversible specific capacity in the range 2.5V - 4.2V vs. lithium metal, and small charge- discharge polarization. Lithium-ion batteries incorporating such electrode compositions may be repeatedly cycled without substantial loss of performance .
• the compounds are prepared using a sol-gel process that proceeds under relatively mild conditions (e.g., at temperatures preferably less than about 1000°C) and requires relatively short reaction times (e.g., on the order of 10-24 hours) .
• the compounds are prepared using a solid-state process, which is well suited to industrial scale synthesis.
• Fig. 1 is an exploded perspective view of an electrochemical cell used to test various electrode compositions .
• Fig. 2 is a plot of two voltage versus capacity profiles for the material prepared according to Comparative Example 1 and Example 1.
• Fig. 3 is a plot of a series of voltage versus capacity profiles for the materials prepared according to Comparative Example 1 and Examples 2 and 8.
• Fig. 4 is a plot of capacity versus cycle number for Comparative Example 1 and Example 2.
• Fig. 5 is a series of x-ray diffraction profiles for materials prepared according to Examples 10-13.
• Fig. 6 is a series of plots showing discharge capacity versus cycle number for Examples 10-13.
• Lithium-chromium-nickel-manganese oxides described herein have the general formula Li Cr x . ⁇ Ji ⁇ In 2 . x 0 4+z where q > 2, 1.0 ⁇ x ⁇ 1.25, 0 ⁇ y ⁇ 0.9, and z ⁇ 0.
• These oxides are particularly useful as electrode compositions for lithium- ion batteries. They are preferably prepared in a sol-gel process in which chromium, lithium, nickel, manganese, and oxygen sources are combined to form a solution (preferably an aqueous solution) , which is then converted to a gel by the addition of a reagent such as ammonium hydroxide (NH 4 OH) .
• a reagent such as ammonium hydroxide (NH 4 OH)
• the gel is then heated under an inert atmosphere (e.g., an argon atmosphere) to convert the gel to the desired oxide.
• these oxides are prepared in a solid-state reaction process in which lithium, chromium, nickel, manganese, and oxygen sources are mixed together (e.g., in an automatic grinder) to form a powder and then heated under an inert atmosphere .
• a variety of materials may be used as the chromium, lithium, nickel, manganese, and oxygen sources.
• the chromium, lithium, nickel, manganese, and oxygen sources When the oxides are prepared in a sol-gel process, the chromium, lithium, nickel, manganese, and oxygen materials must be soluble in the medium used to prepare the gel. For example, in the case of aqueous solutions, the chromium, lithium, nickel, manganese, and oxygen sources must be water-soluble.
• a single material may serve as a source for more than one of these elements.
• Preferred materials are those in which the elemental constituents (with the exception of chromium, lithium, nickel, manganese, and at least some of the oxygen) form volatile by-products during the heating step such that these elemental constituents do not become part of the final oxide product .
• the resulting oxide product therefore, contains only lithium, chromium, nickel, manganese, and oxygen as its elemental constituents. In this way, the oxide product is essentially free of impurities which might otherwise compromise electrode performance.
• suitable materials include nitrogen- containing compounds (which can liberate nitrogen- containing gas during heating) , carbon-containing compounds (which can liberate, e.g., carbon dioxide and/or carbon monoxide during heating) , and hydrogen- containing compounds (which can liberate, e.g., water vapor during heating) .
• nitrogen- containing compounds which can liberate nitrogen- containing gas during heating
• carbon-containing compounds which can liberate, e.g., carbon dioxide and/or carbon monoxide during heating
• hydrogen- containing compounds which can liberate, e.g., water vapor during heating
• Specific examples include nitrates, hydroxides, and esters of organic acids such as acetates, citrates, tartrates, and oxalates .
• the heating temperature and stoichiometric ratios of reactants determine the crystal structure (and associated parameters such as lattice constants and unit cell volume) of the oxide product, as well as whether the product is a single or multi-phase material.
• temperatures less than 900°C are preferred, with temperatures in the range 500-800°C being particularly preferred.
• temperatures less than 1000°C are generally preferred, with temperatures in the range of about 700°C to about 900°C being particularly preferred.
• Electrodes were prepared as follows. About 12 wt.% Li 2 Cr x _ y Ni y Mn 2 _ x 0 4+z (prepared as described below), 6 wt.% Kynar Flex 2801 (a vinylidene fluoride- hexafluoropropylene copolymer commercially available from Atochem) , 10 wt. % EC/PC (ethylene carbonate/propylene carbonate, 50/50 by volume), 1.5 wt .
• % Super S carbon black commercially available from MMM Carbon, Belgium
• 70.5 wt.% acetone were thoroughly mixed by stirring in a sealed bottle at 50°C for four hours to form a slurry.
• the slurry was then spread in a thin layer (about 150 micrometers thick) on a glass plate using a doctor blade spreader. After evaporating the acetone, the resulting film was peeled from the glass and a circular electrode measuring 1 cm in diameter was punched from the film using an electrode punch.
• the circular electrode was then weighed and the active mass (the total weight of the circular electrode multiplied by the fraction of the electrode weight made up by Li q Cr x _ y Ni y Mn 2 _ x 0 4+z ) was calculated, after which the circular electrode was sealed in a polyethylene bag with a heat sealer until used to assemble an electrochemical cell.
• each circular electrode was first placed in diethyl ether for about 5 minutes to remove EC/PC and form pores in the electrode that the electrolyte will fill during cell construction. The electrodes were then taken into an argon-filled glove box where the electrochemical cell was constructed.
• FIG. 1 An exploded perspective view of the electrochemical cell 10 is shown in Fig. 1.
• a stainless steel cap 24 and special oxidation resistant case 26 contain the cell and serve as the negative and positive terminals respectively.
• the cathode 12 was the electrode prepared as described above.
• the anode 14 was a lithium foil having a thickness of 125 micrometers; the anode also functioned as a reference electrode.
• the cell featured 2320 coin-cell hardware, equipped with a spacer plate 18 (304 stainless steel) and a disc spring 16 (mild steel) . The disc spring was selected so that a pressure of about 15 bar would be applied to each of the cell electrodes when the cell was crimped closed.
• the separator 20 was a Celgard #2502 microporous polypropylene film (Hoechst- Celanese) , which had been wetted with a 1M solution of LiPF 6 dissolved in a 30:70 volume mixture of ethylene carbonate and diethyl carbonate (Mitsubishi Chemical) .
• a gasket 27 is used as a seal and also serves to separate the two terminals.
• LiOH-H 2 0 (FMC Corp., 98%) was dissolved in 70 mis of distilled water. While stirring, the LiOH solution was added dropwise to the transition metal solution over a period of about 10 minutes. Finally, about 26 mis of NH 4 OH was added dropwise over a period of about 10 minutes to form a gel. The gel was then placed in a "Fisher-Brand" muffle oven set to 180°C to dry and solidify the gel overnight in air. After initial drying, the solidified gel was powdered in a Retsch model RM-0 automatic grinder for about 15 minutes.
• the powdered gel was then heated to 500°C using a Lindberg tube furnace equipped with stainless steel furnace tubes and sealed end caps. After the gel had been loaded into the furnace tube, but before initiating heating, the end caps were sealed, and the furnace tube thoroughly purged with UHP-grade argon (Canadian Liquid Air), to remove unwanted air. UHP-grade argon was passed at a rate of about
• the heating profile was as follows: 10°C/minute from 30°C to 500°C, followed by a
• the crystal structure was determined based upon the x-ray diffraction data as described in (a) C.J. Howard and R.J. Hill, Australian Atomic Energy Commission Report No. M112 (1986) ; and (b) D.B. Wiles and R.A. Young, J. Appl . Cryst . , 14:149-151 (1981).
• the diffraction pattern of the sample can be fit by either of two "homeomorphic" crystal structures.
• the unit volume refers to the volume of the crystal per formula unit of the material, the formula unit being Li q Cr x . y Ni y Mn 2 . x 0 4+2 .
• the unit cell contains 8 formula units.
• the unit cell contains 3/2 formula units.
• the unit cell contains 3/2 formula units.
• Example 1 had a hex structure, with nickel placed randomly at the same crystallographic sites as manganese and chromium.
• Example 1 An electrochemical cell was constructed according to the above-described procedure using the material of Example 1 as the cathode. The cell was cycled between voltage limits of 2.5V and 4.2V using a current of 15 mA/g. Reversible and irreversible capacities were determined and are reported in Table 1
• the gel was then placed in a "Fisher-Brand" muffle oven set to 170°C to dry and solidify the gel overnight in air. After initial drying, the solidified gel was powdered in a Retsch model RM-0 automatic grinder for about 10 minutes.
• the powdered gel was then heated to 500°C using a Lindberg tube furnace equipped with stainless steel furnace tubes and sealed end caps . After the gel had been loaded into the furnace tube, but before initiating heating, the end caps were sealed, and the furnace tube thoroughly purged with UHP-grade argon (Canadian Liquid Air) , to remove unwanted air.
• UHP-grade argon Canadian Liquid Air
• UHP-grade argon was passed at a rate of about 150 cc/min through fittings in the sealed end caps during the synthesis.
• the heating profile was as follows: from 30°C to 150°C in 20 minutes, followed by a 3 hour soak at 150°C. The sample was then heated to
• the voltage profile for a cell prepared using material from Comparative Example 1 and a cell prepared using material from Example 1 were obtained and are shown in Fig. 2.
• the voltage profile for Comparative Example 1 is represented by a solid line and the voltage profile for Example 1 is represented by a dashed line.
• Examples 2-7 were prepared following the procedure set forth in Example 1 except that the relative amounts of reactants (Cr (N0 3 ) 3 -9H 2 0,
• Ni(N0 3 ) 2 -6H 2 0, Mn(CH 3 COO) 2 -4H 2 0, and LiOH-H 2 0) were selected to yield a product having the formula Li 2 Cr 0 S5 Ni 04 Mn 075 0 4+z where z ⁇ 0.
• Example 1 was followed up to the point of soaking the material at 500°C for 10 hours and cooling it to room temperature. A portion of this material was saved for further use and is referred to as Example 3. Five 2 gram samples of the powdered material were further subjected to a heat soak treatment in the furnace for 10 hours at the following temperatures:
• Example 6 900°C (Example 6) , and 1000°C (Example 7) .
• quartz furnace tubes were used.
• electrochemical cells were constructed according to the procedure described above using, as the cathode, samples prepared according to Examples 2- 7. Specifically, six cells were prepared using the material of Examples 2-7 and cycled between voltage limits of 2.5V and 4.2V using currents of 15 mA/g. Reversible and irreversible capacities were determined and the results are reported in Table 1.
• Example 2 has an increased capacity, a reduced irreversible capacity, and a reduced charge-discharge polarization compared to Comparative Example 1.
• FIG. 4 capacity versus cycle number of Example 2 is shown.
• a cell prepared using material from Comparative Example 1 was subjected to 11 cycles during which the cell was charged and discharged between 2.5V and 4.5V with a current of 15 mA/g.
• capacity upon charge is represented by open triangles and capacity upon discharge is represented by inverted triangles.
• Example 2 capacity upon charge is represented by solid diamonds and capacity upon discharge is represented by solid circles.
• charge and discharge occurred over a period of 10 hours.
• the cycling profile for Example 2 was as follows: between 2.5V and 4.2V (cycles 1 and 2); between 2.5V and 4.5V (cycles 3 and 4); and between 2.5V and 4.2V (cycles 5 through 100) .
• the cell of Example 2 was discharged with a current of 50 mA/g and charged with a current of 15 mA/g. At every 10th cycle the cell was subjected to a 150 mA/g "C- rate" discharge current.
• the C-rate discharge was followed by the successive discharge of the cell with the following currents: 75 mA/g, 37.5 mA/g, 18.75 mA/g, 9.375 mA/g, and 4.687 mA/g. Following the C-rate discharge, the cell was charged with a current of 15 mA/g. The data are shown in Fig. 4 and demonstrate excellent capacity retention and cycle-life.
• Example 8 was prepared following the procedure set forth in Example 2 except that the relative amounts of reactants were selected to yield a product having the formula Li 2 Cr 045 Ni 08 Mn 075 0 4+z where z ⁇ 0.
• the crystal structure, lattice constants, and unit volume were determined for each sample according to the procedure in Example 1. The results are summarized in Table 1.
• An electrochemical cell was constructed according to the procedure described above using, as the cathode, material prepared according to Example 8.
• Example 8 has an increased reversible capacity and a reduced irreversible capacity compared to Comparative Example 1.
• Example 8 has a reduced charge-discharge polarization compared to Comparative Example 1.
• the data indicate that the increased nickel content reduces the charge-discharge polarization.
• An electrochemical cell was constructed according to the above-described procedure using the material of Example 9 as the cathode. The cell was cycled between voltage limits of 2.5V and 4.2V using a current of 15 mA/g. Reversible and irreversible capacities were determined and are reported in Table 1.
• Comparative Example 2 was prepared following the procedure set forth in Comparative Example 1 except that the relative amounts of reactants (Cr (N0 3 ) 3 -9H 2 0, Mn(CH 3 COO) 2 -4H 2 0, and LiOH-H 2 0) were selected to yield a product having the formula Li 2 Cr 1 ⁇ M ⁇ .0 O 4+z where z > 0.
• a 2 gram sample of the powdered material was further subjected to a heat treatment in the furnace for 24 hours at 700°C. The crystal structure, lattice constants, and unit cell volume were determined as described in Example 1 and are reported in Table 1.
• An electrochemical cell was constructed and cycled according to the procedure described in Example 1
• Ni (N0 3 ) 2 -6H 2 0 and 8.666g of Mn (CH 3 C00) 2 -4H 2 0 were thoroughly mixed by grinding in an automatic grinder for about 15 minutes.
• the powdered material was placed in a muffle oven set to 110°C to dry for 3 hours.
• the material was then heated to 500°C for 15 hours under argon using the procedures set forth in Example 1 to yield a compound having the formula Li 2 Cr 085 Ni 04 Mn 075 0 4+z where z ⁇ 0.
• Examples 10-13 were prepared following the procedure of Example 1 except that a 3g sample of the material was further subjected to a heat treatment in the furnace for 15 hours at the following temperatures: 600°C (Example 10), 700°C (Example 11), 800°C (Example
• Powder x-ray diffraction patterns were obtained for each sample and are shown in Fig. 5.
• the crystal structure, lattice constants, and unit volume were determined as described in Example 1, and are reported in Table 1.
• Electrochemical cells were constructed as described above using the materials of Examples 10-13 and cycled with a current of 15 mAh/g as follows: between 2.5V and 4.2V for charge-discharge cycles 1 and 2, between 2.5V and 4.5V for charge-discharge cycles 3 and 4 , and between 2.5V and 4.2V for the remaining charge-discharge cycles.
• the resulting discharge capacity versus cycle number is shown in Fig. 6.
• the solid triangles and circles represent two cells made from the same material and subjected to the same test conditions. For Examples 11 and 13, cycling of the cell represented by triangles was terminated prior to terminating the cycling of the cell represented by circles. The data demonstrate excellent cycling behavior. Reversible and irreversible capacities for each of these cells were determined and are reported in Table 1.
• Example 14 was examined by x-ray diffraction and exhibited a diffraction pattern nominally the same as Example 13 with almost identical lattice constants.

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• 1997
  • 1997-10-15 US US08/950,628 patent/US5900385A/en not_active Expired - Lifetime
• 1998
  • 1998-02-17 AU AU63323/98A patent/AU6332398A/en not_active Abandoned
  • 1998-02-17 JP JP2000515833A patent/JP4205308B2/ja not_active Expired - Fee Related
  • 1998-02-17 KR KR10-2000-7003974A patent/KR100485982B1/ko not_active Expired - Fee Related
  • 1998-02-17 WO PCT/US1998/003289 patent/WO1999019255A1/en not_active Ceased
  • 1998-09-16 ZA ZA9808465A patent/ZA988465B/xx unknown

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