Batteries magnesium-based

F—Magnesium Magnesium anode Carbon, vanadium pentoxide, and magnesium chloride Magnesium-based thermal batteries... 

A number of cylindrical and flat magnesium-based cells have been developed on a commercial scale, mainly for military applications where high discharge currents and low unit weight are important. However, for most of these applications, magnesium batteries have now been replaced by various lithium/organic systems. There are no commercial aluminium-based Leclanchd cells. Magnesium and aluminium are both exploited as anodes in metal-air cells which are considered below. 

Nonaqueous solvents can form electrolyte solutions, using the appropriate electrolytes. The evaluation of nonaqueous solvents for electrochemical use is based on factors such as -> dielectric constant, -> dipole moment, - donor and acceptor number. Nonaqueous electrochemistry became an important subject in modern electrochemistry during the last three decades due to accelerated development in the field of Li and Li ion - batteries. Solutions based on ethers, esters, and alkyl carbonates with salts such as LiPF6, LiAsly, LiN(S02CF3)2, LiSOjCFs are apparently stable with lithium, its alloys, lithiated carbons, and lithiated transition metal oxides with red-ox activity up to 5 V (vs. Li/Li+). Thereby, they are widely used in Li and Li-ion batteries. Nonaqueous solvents (mostly ethers) are important in connection with other battery systems, such as magnesium batteries (see also -> nonaqueous electrochemistry). 

Gazotti, W.A., et al. 1997. A new configuration of the solid-state battery Magnesium polymer proton conductor gold, based on the use of poly(o-methoxyaniline). Synth Met 90 31. 

Intensive development of NiMH battery technology is underway in many places worldwide. Widespread activity has been reported on magnesium-based metal hydride alloys for capacity and cost advantages, evaluation of bipolar NiMH designs, satellite NiMH battery development, and a myriad of technical goals too lengthy to list here. However, the most intensive NiMH development at this time involves efforts to raise specific power to new levels and to reduce cost. 

Another parameter which will have a very definite bearing on the choice of battery type is cell voltage, particularly on-load voltage, which are tabulated in Table 2.1 for various types of primary battery. It can be seen that these range from 0.75V/ceJI (mercury-cadmium) to over 3 V with some of the lithium and magnesium based organic electrolyte systems. 

The U.S. domestic capacity of ammonium perchlorate is roughly estimated at 31,250 t/yr. The actual production varies, based on the requirements for soHd propellants. The 1994 production ran at about 11,200 t/yr, 36% of name plate capacity. Environmental effects of the decomposition products, which result from using soHd rocket motors based on ammonium perchlorate-containing propellants, are expected to keep increasing pubHc pressure until consumption is reduced and alternatives are developed. The 1995 price of ammonium perchlorate is in the range of 1.05/kg. Approximately 450 t/yr of NH ClO -equivalent cell Hquor is sold to produce magnesium and lithium perchlorate for use in the production of batteries (113). Total U.S. domestic sales and exports for sodium perchlorate are about 900 t/yr. In 1995, a solution containing 64% NaClO was priced at ca 1.00/kg dry product was also available at 1.21/kg. 

Other common anode materials for thermal batteries are lithium alloys, such as Li/Al and Li/B, lithium metal in a porous nickel or iron matrix, magnesium and calcium. Alternative cathode constituents include CaCr04 and the oxides of copper, iron or vanadium. Other electrolytes used are binary KBr-LiBr mixtures, ternary LiF-LiCl-LiBr mixtures and, more generally, all lithium halide systems, which are used particularly to prevent electrolyte composition changes and freezing out at high rates when lithium-based anodes are employed. 

Modem electrochemistry is concerned not only with systems based on aqueous solutions but also with solvent-free systems. Indeed, it is in such systems that many important electrochemical processes are carried out, such as the production of metals (aluminum, sodium, and magnesium) and the development of high-energy-density batteries. 

Metalhc hthium has a variety of uses. It is used as an anode material in batteries and as a heat transfer agent. Magnesium-hthium alloys are used to produce armor plate and aerospace materials, while aluminum-hthium alloys find applications in the aircraft industry. Lithium is also used to produce chemical reagents such as LiAlH4 (a reducing agent) and n-butyhthium (a strong base). 

Khoo T, Somers A, Torriero AAJ, MacFariane DR, Howlett PC, Forsyth M (2013) Discharge behaviour and interfacial properties of a magnesium battery incorporating trihexyl(tetradecyl) phosphonium based ionic liquid electrolytes. Electrochim Acta 87 701-708... 

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