Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Include electrolyte chemically specified and method
Patent
1995-11-06
1998-11-10
Skapars, Anthony
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Include electrolyte chemically specified and method
429218, H01M 614, H01M 496
Patent
active
058341382
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a negative electrode material used in a non-aqueous liquid electrolyte secondary cell. More particularly, it relates to a negative electrode material of a carbonaceous material capable of doping and dedoping lithium ions. The invention also relates to a method for producing the material and a non-aqueous liquid electrolyte secondary cell employing the material.
BACKGROUND ART
With recent progress in electronics, a small-sized portable electronic equipment, such as a camera-integrated VTR, portable telephone or a lap-top computer, has been developed, and a strong demand has been raised for development of a small-sized and lightweight secondary cell with high energy density as a portable power source used for the equipment.
Of the secondary cells, satisfying this demand, a non-aqueous liquid electrolyte secondary cell of a high energy density, which is capable of generating a theoretically high voltage and which employs light metals, such as lithium, sodium or aluminum as an active material for the negative electrode, is most promising. In particular, the non-aqueous liquid electrolyte secondary cell in which lithium ion charging/discharging is done via a non-aqueous liquid electrolyte, is thought to be able to develop high output and high energy density as compared to the aqueous solution based liquid electrolyte secondary cell, such as nickel/cadmium cell or a lead storage cell. For this reason, investigations in this type of the non-aqueous liquid electrolyte secondary cell are proceeding briskly.
If, in such non-aqueous liquid electrolyte secondary cell, light metals, such as lithium metal, are simply used as they are as the negative electrode material, lithium metals tend to be precipitated in a dendritic form in the negative electrode during charging. Since the current density becomes exceedingly high at the distal end of the dendrite, the cycle life is shortened due to decomposition of the liquid electrolyte. If the dendrite is grown excessively, internal shorting in the cell is likely to be produced. For assuring the operating time of the small-sized electronic equipment and the service life of power source packages, it has been strongly desired to develop a negative electrode material capable of realizing a high energy density cell.
With this in view, for prohibiting precipitation of, for example, dendritic metals, such as metal lithium, for improving cyclic charging/discharging characteristics of the cell, it has been proposed to use a carbonaceous material capable of doping and dedoping lithium ions as the active materials for the negative electrode as a material for a negative electrode for a non-aqueous liquid electrolyte secondary cell (JP Patent Kokai Publication JP-A-62-90863).
It is believed that, theoretically, lithium ions are electro-chemically doped and dedoped in an interlayer space of the graphite-like layered structure of the carbonaceous material at a rate of one lithium atom per six carbon atoms. For such carbonaceous materials, cokes (such as pitch coke, needle coke or petroleum coke) or sintered organic high molecular compounds, such as furan resins or natural high molecular materials sintered and carbonized at a suitable temperature, as disclosed in JP-Patent Kokai Publication JP-A-4-308670, are mainly used in view of production cost ad cyclic charging/discharging characteristics.
Of these carbonaceous materials, those produced by sintering crystalline cellulose, which is a natural high molecular material susceptible to fluctuations in the polymerization degree and hence in the properties of the sintered product to a lesser extent than synthetic high molecular material (JP-Patent Kokai publication JP-A-2-54866) is drawing the notice. This carbonaceous material is thought to be promising as a material of a negative electrode of a non-aqueous liquid electrolyte secondary cell in that it has a high charging capacity as compared to cokes. In distinction from a synthetic high molecular material prepared from fossil resources, cellulose is
REFERENCES:
patent: 1379222 (1921-05-01), Seaman
patent: 1462752 (1923-07-01), Jacobs
patent: 1538505 (1925-05-01), Atkinson
patent: 1903705 (1933-04-01), Nikaido
patent: 3961025 (1976-06-01), Harendza-Harinxma
patent: 4318710 (1982-03-01), Pilipski
patent: 5153082 (1992-10-01), Ogino et al.
patent: 5169736 (1992-12-01), Bittihn et al.
T. Ohzuku, et al., Formation of Lithium-Graphite Intercalation Compounds in Nonaqueous Electrolytes and Their Application as a Negative Electrode for a Lithium Ion (Shuttlecock) Cell, Journal of the Electrochemical Society, vol. 140, No. 9, 1 Sep. 1993, pp. 2490-2498, XP 000424105.
Patent Abstracts of Japan, vol. 014, No. 222 (E-0926), 10 May 1990 & JP 02054866 A (Mitsubishi Petrochem Co Ltd;Others: 01), 23 Feb. 1990.
Adachi Momoe
Akashi Hiroyuki
Azuma Hideto
Imoto Hiroshi
Kitamura Kenichi
Skapars Anthony
Sony Corporation
LandOfFree
Negative electrode material for non-aqueous liquid electrolyte s does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Negative electrode material for non-aqueous liquid electrolyte s, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Negative electrode material for non-aqueous liquid electrolyte s will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1514942