Industrial cathode materials

Uses. Silver fluoride has found many laboratory and special industrial appHcations. It is used as a soft (nHld) fluorinating agent for selective fluorination (7—17), as a cathode material in batteries (qv) (18), and as an antimicrobial agent (19). Silver fluoride is commercially available from Advance Research Chemicals, Inc., Aldrich Chemicals, Cerac Corp., Johnson/Matthey, PCR, Atochem, and other sources in the United States. The U.S. price of silver fluoride in 1993 was 1000— 1400/kg and the total U.S. consumption was less than 200 kg/yr. 

Batteries. Many batteries intended for household use contain mercury or mercury compounds. In the form of red mercuric oxide [21908-53-2] mercury is the cathode material in the mercury—cadmium, mercury—indium—bismuth, and mercury—zinc batteries. In all other mercury batteries, the mercury is amalgamated with the zinc [7440-66-6] anode to deter corrosion and inhibit hydrogen build-up that can cause cell mpture and fire. Discarded batteries represent a primary source of mercury for release into the environment. This industry has been under intense pressure to reduce the amounts of mercury in batteries. Although battery sales have increased greatly, the battery industry has aimounced that reduction in mercury content of batteries has been made and further reductions are expected (3). In fact, by 1992, the battery industry had lowered the mercury content of batteries to 0.025 wt % (3). Use of mercury in film pack batteries for instant cameras was reportedly discontinued in 1988 (3). 

Refractories in the Aluminum Industry. Carbon materials are used in the HaH-Heroult primary aluminum cell as anodes, cathodes, and sidewalls because of the need to withstand the corrosive action of the molten fluorides used in the process (see Aluminumand aluminum alloys). 

We managed to obtain dense and solid thin films of 3d-metal oxides using the techniques of electrochemical deposition from aqueous fluorine-containing electrolytes. The films have been studied as a possible cathode material for secondary cells. The best samples show good cycle retention and acceptable specific capacity in the range of 180 mAh/g. They also feature a plateau of electrochemical potential at approximately 3,5 V, which is acceptable for present industrially produced electrochemical devices. 

Transition-metal oxides and their mixtures are widely employed in numerous industrial applications, especially as cathode materials for batteries and fuel cells [1,2], Practice poses certain well-known requirements to oxide materials, first of all, to uniformity of the size distribution of particles, to homogeneity of mixed oxides, etc. To meet these demands, two broad categories of methods are now in use, vs (i) mechanical methods and (ii) chemical methods. 

Studies at the Lewis Research Center of the National Aeronautic and Space Administration22 and at the Frankford Arsenal of the U.S. Army23 have shown that poly(carbon monofluoride) is a superior solid lubricant under heavy loads, in high temperatures, in oxidizing atmospheres, and under other extreme conditions. Researchers at the U.S. Army Electronics Command at Fort Monmouth, N.J.24 25 and industrial scientists in Japan have recently demonstrated a high potential for the use of poly(carbon monofluoride) as a cathode material in high-energy batteries. 

Cathode Iron is a very cheap cathode material with a relatively low hydrogen overvoltage (e.g. [25]). It is of interest for industrial applications. In order to avoid corrosion during interruption of the current, stainless steel may be suitable, especially in laboratory cells where the increased electrical resistance and hydrogen overvoltage are irrelevant. 

The industry continues to research improvements in the present production cells. Special attention is being focused on developing inert anodes and cathodes. Ferrites may find use as inert anodes, while titanium diboride may become the optimum material for cathodes. Before commercial use of inert electrodes can be achieved, cell sidewall materials must be developed which will withstand extremely reactive conditions and further improvements (i.e., less solubility of the anode and cathode materials are required). Over the past 15 years, American and Canadian aluminum producers have channeled nearly 1.5 billion into manufacturing technology research, the modernization and computerization of plant facilities, and new and better applications for the metal. Some of the results achieved thus far include ... 

The first investigation of Li Co02 was carried out by Mizushima et al. in 1980," where the material was suggested as a possible positive electrode for lithium-ion rechargeable batteries. In 1991 Sony Corporation commercialized the first lithium-ion battery in which lithium cobalt oxide was used as the positive electrode and graphite (carbon) as the negative electrode. Since then, LiCo02 has been the most widely used cathode material in commercial hthium-ion batteries and retains its industrial importance as a cathode material. 

The mining of mercury has declined in recent decades, as major international concern over the health threat of mercury s extensive pollution of the environment has mounted. Much American freshwater fish is contaminated. The U.S. Environmental Protection Agency estimates 3,000 uses of mercury. Mercury usage is down in the chloroalkali industry, in which mercury is the cathode material used in the electrolysis of sodium chloride solutions, which produce sodium hydroxide and chlorine. An abundance of... 

Among his research interests are investigation of the cathode materials for the lithium-ion batteries, physical-chemical properties of low-temperature ionic liquids and electrochemistry of refractory metals in ionic liquids. Recently he has been taking part in the research and optimization on the industrial scale of processes of Zn, Zn-Fe and Zn-Ni alloy deposition. 

H. Vandenbotre, R. Laysen, H. Nackaerts, and Ph.van Asbroeck, Int J. Hydrogen Energy 9,277 (1984). K. Yamakawa, H. Thbakino, K. Akiyoshi, H. Inoue, and K. Yoshimoto. Ni-S Amorphous Alloy as Cathode Material in Chlorine Cell, In F. Hine, R.E. White, W.B. Burlington, and R.D. Vaijian (eds). Electrochemical Engineering in the Chlor-Alkali Industry, The Electrochemical Society Inc. Princeton, NJ (1988), p. 174. 

The Japan Soda Industry Association (JSIA) began further development of oxygen cathodes in 1994 [ 11 ]. Their focus was on development of cathode materials, the structure of the oxygen cathode, life testing in cells of various types and sizes, and scale-up procedures. 

Industrially important sihcides have been synthesized by microwave reactions. A notable example is MoSi [13]. Metal phosphates have extensively been studied for applications as phosphors, catalysts and as cathode materials in lithium ion batteries. Several lanthanide orthophosphates, LnPO (Ln=La, Ce, Nd, Sm, Eu, Gd and Tb), are obtained by microwave heating of an aqueous solution of Ln(III) nitrate and NH H PO [14], Highly crystalline ohvine LiFePO nanorods are directly obtained within 5 min by microwave heating of lithium hydroxide, iron acetate and phosphoric acid in tetraethyleneglycol [15]. 

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