Chemistry: electrical and wave energy – Apparatus – Electrolytic
Utility Patent
1999-02-04
2001-01-02
Bell, Bruce F. (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S290150, C204S294000, C204S291000, C205S508000, C205S431000, C205S432000, C205S433000, C205S450000, C205S457000, C423S334000, C423S365000, C423S409000, C106S287260, C106S287300, C361S502000, C361S508000, C361S509000, C361S516000, C361S528000, C361S532000, C148S206000, C148S238000, C501S096100
Utility Patent
active
06168694
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention generally relates to the field of methods for and products of manufacturing component parts in energy storage devices. More particularly, the present invention relates to the field of methods for and products of producing high surface area electrode by processing nitride, carbonitride, and oxycarbonitride materials for the application of supercapacitor.
2. Description of The Prior Art
The following is a list of prior art references that are believed to be pertinent to the field of methods for and products of producing high surface area electrode by processing nitride, carbonitride, and oxycarbonitride materials for the application of energy storage devices:
1. U.S. Pat. No. 5,837,630 issued on Nov. 17, 1998 to Owens et al. for “High Surface Area Mesopourous Desigel Materials and Methods for Their Fabrication” (hereafter “Owens”);
2. U.S. Pat. No. 5,807,430 issued on Sep. 15, 1998 to Zheng et al. for “Method and Composition Useful Treating Metal Surfaces” (hereafter “Zheng”);
3. U.S. Pat. No. 5,680,292 issued on Oct. 21, 1997 to Thompson, Jr. et al. for “High Surface Area Nitride, Carbide and Boride Electrodes and Methods of Fabrication Thereof” (hereafter “Thompson”);
4. U.S. Pat. No. 5,601,938 issued on Feb. 11, 1997 to Mayer et al for “Carbon Aerogel Electrodes for Direct Energy Conversion” (hereafter “Mayer”);
5. U.S. Pat. No. 5,079,674 issued on Jan. 7, 1992 to Malaspina for “Supercapacitor Electrode and Method of Fabrication Thereof” (hereafter “Malaspina”);
6. U.S. Pat. No. 5,062,025 issued on Oct. 29, 1991 to Verhoeven et al. for “Electrolytic Capacitor and Large Surface Area Electrode Element Therefor” (hereafter “Verhoeven”);
7. U.S. Pat. No. 4,851,206 issued on Jul. 25, 1989 to Boudart et al. for “Methods and Compositions Involving High Specific Surface Area Carbides and Nitrides” (hereafter “Boudart ('206)”);
8. U.S. Pat. No. 4,717,708 issued on Jan. 5, 1988 to Cheng et al. for “Inorganic Oxide Aerogels and Their Preparation” (hereafter “Cheng”);
9. U.S. Pat. No. 4,515,763 issued on May 1985 to Boudart et al. for “High Specific Surface Area Carbides and Nitrides” (hereafter “Boudart ('763)”);
10. U.S. Pat. No. 4,426,336 issued on Jan. 17, 1984 to McCandlish et al. for “Novel Molybdenum Oxycarbonitride Compositions” (hereafter “McCandlish”);
11. U.S. Pat. No. 4,327,400 issued on Apr. 27, 1982 to Muranaka et al. for “Electric Double Layer Capacitor” (hereafter “Muranaka”
12. U.S. Pat. No. 4,327,065 issued on Apr. 27, 1982 to von Dardel et al. for “Method of Preparing Silica Aerogel” (hereafter “von Dardel”);
13. U.S. Pat. No. 3,977,993 issued on Aug. 31, 1976 to Lynch for “Metal Oxide Aerogels” (hereafter “Lynch”);
14. C. Z. Deng, P. A. J. Pynenburg, and K. C. Tsai, “Improved Porous Mixture of Molybdenum Nitride and Tantalum Oxide as a Charge Storage Material”,
J Electrochem. Soc
., vol. 145, p. L61 (April 1998) (hereafter “Deng”); and
15. S. L. Roberson, D. Finello, R. F. Davis, T. Liu and B. E. Conway,
The
7
th International Seminar on Double Layer Capacitors and Similar Energy Storage Devices
(Dec. 8-10, 1997, Deerfield Beach, Fla.) (hereafter “Roberson”).
In general, electrochemical capacitors are capacitive energy storage devices based on double-layer capacitance or pseudocapacitance. The potential power density and cycle life of electrochemical capacitors are two orders of magnitudes higher than those of rechargeable batteries. As compared with batteries, electrochemical capacitors can be characterized as having low energy density, high power density and a high cycle life. Further, in an electric circuit, an electrochemical capacitor behaves more like a classical dielectric capacitor than a battery, hence its name.
The component parts of an electrochemical capacitor include electrode, electrolyte, seperator. Electrode material is a key element in electrochemical capacitor. The requirement of high energy and power density electrochemical capacitor intrigues development on miniaturization and weight reduction of electrochemical capacitor. One approach to increase energy and power density is to increase assessable surface area of electrode. The pore size must be large enough to let electrolyte assess into the pore, and smaller enough to have high surface area per volume or per weight of electrode material. The cohesion of electrode and adhesion to the current collector is a key point to realize high conductivity and power density of electrode materials, such as nitride. Contacting resistance can increase the resistance of the capacitor.
There are four basic types of electrode for supercapacitor application. Activated carbon or foam represents one type of electrode materials, as disclosed by Mayer, Malaspina, and Muranaka. Typical capacitance obtained from an electric double layer is in the range of 20~40 mF/cm
2
.
Certain transition metal oxides such as RuO
2
and IrO
2
posses pseudocapacitance. Pseudocapacitance arise from highly reversible reactions, such as redox reactions, which occurs at or near the electrode surfaces. Capacitance of 150~200 mF/cm
2
have been observed for RuO
2
films.
The third type consists of metallic bodies which are mechanically or chemically etched to provide a roughened surface and high specific surface area, as disclosed by Verhoeven. High surface area metal electrode are limited by electrochemical stability. Metals are generally unstable in oxidizing environments, therefore their use is limited as to the positive, reducing electrode or anode.
The fourth type contains metal nitride. Metal nitride is in general conductive and exhibit pseudocapacitance. Especially molybdenum nitride, as pointed out by Roberson, exhibits high energy density.
Among these four types of electrode material, nitride electrode has great potential for supercapacitor application due its much higher energy density than carbon and metal, and similar energy density as RuO
2
with much low cost.
Various methods have been developed to produce high surface area of nitride materials. Owens disclosed a high surface area mesopourous desigel materials which are fabricated as nitrides, carbides, borides, and silicides of metals. Thompson disclosed a method to deposit oxide coating onto current collector followed by exposing the metal oxide layer at elevated temperature to a source of nitrogen, carbon or boron in a chemically reducing environment to form metal nitride, carbide and boride film.
Roberson disclosed a method to deposit Mo,N coating electrode via chemical vapor deposition (CVD).
McCandlish disclosed a molybdenum oxycarbonitride composition. The compositions have the general formula: MoOaCbNr, where a, b and c are non-zero decimal values and the sum: a+b+c, is less than or equal to about one (1). The compositions can be obtained by the relatively low temperature thermal decomposition of an anime molybdate and can be amorphous, poorly crystalline, or substantially crystalline and can possess high surface areas in the region of about 60 to 130 m
2
/g.
It is desirable to provide a new type of composite electrode materials possessing nitride, carbonitride and oxycarbonitride aerogel and methods of fabrication thereof for supercapacitor applications.
SUMMARY OF THE INVENTION
In one aspect, the present invention relates to assembling an electrical storage device that has both a high energy and a high power density. It is a unique method for and product of processing nanostructure nitride, carbonitride and oxycarbonitride electrode powder materials by utilizing sol gel related technology. The pore size is controlled by incorporating unhydrolyzable organic ligands or templates into gel network, which is removed by pyrolysis. The pore size can be controlled by the size of templates and narrow pore size distribution is achieved.
It is an object of the present invention to provide new transition metal nitride, carbonitride, and oxycarbonitride electrode materials and methods to fabricate the same.
It is another object of the present invention to provide a composite electrod
Chu Chung-tse
Huang Yuhong
Wei Oiang
Zheng Haixing
Bell Bruce F.
Chemat Technology Inc.
Chen Tony D.
Fong Jerry
Roza Thomas I.
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