Molten-salt-electrolyte battery

Because of the interest in its use in elevated-temperature molten salt electrolyte batteries, one of the first binary alloy systems studied in detail was the lithium-aluminium system. As shown in Fig. 1, the potential-composition behavior shows a long plateau between the lithium-saturated terminal solid solution and the intermediate P phase "LiAl", and a shorter one between the composition limits of the P and y phases, as well as composition-dependent values in the single-phase regions [35], This is as expected for a binary system with complete equilibrium. The potential of the first plateau varies linearly with temperature, as shown in Fig. 2. 

Finally, high-temperature molten salt electrolyte batteries (NaS, Zebra) require completely inorganic separators capable of withstanding liquid metal temperature and chemical attack, effectively acidic conditions at temperatures >200 °C. Beta-AlaOs has been significantly engineered to serve this role [10]. 

T. D. Kaun, M. C. Hash, and D. R. Simon, Sulfide Ceramics in Molten-Salt Electrolyte Batteries, Role of Ceramics in Advanced Electrochemical Systems, P. N. Kumta, G. S. Rohrer, and U. Bala-chandran, eds.. Ceramic Transactions, Vol. 65, 1996, p. 293. 

Because of the interest in its use in elevated-temperature molten salt electrolyte batteries, one of the first binary alloy systems studied in detail was the... 

A battery system closely related to Na—S is the Na—metal chloride cell (70). The cell design is similar to Na—S however, ia additioa to the P-alumiaa electrolyte, the cell also employs a sodium chloroalumiaate [7784-16-9J, NaAlCl, molten salt electrolyte. The positive electrode active material coasists of a transitioa metal chloride such as iroa(Il) chloride [7758-94-3] EeQ.25 or nickel chloride [7791-20-0J, NiQ.25 (71,72) in Heu of molten sulfur. This technology is in a younger state of development than the Na—S. 

In 1963, Major (Dr.) Lowell A. King (Figure 1.1) at the U.S. Air Force Academy initiated a research project aimed at finding a replacement for the LiCl/KCl molten salt electrolyte used in thermal batteries. 

U.S. Air Force Academy in 1961. He was an early researcher in the development of low-temperature molten salts as battery electrolytes. At that time low temperature meant close to 100 °C, compared to many hundreds of degrees for conventional molten salts. His work led directly to the chloroaluminate ionic liquids. 

Early in their work on molten salt electrolytes for thermal batteries, the Air Force Academy researchers surveyed the aluminium electroplating literature for electrolyte baths that might be suitable for a battery with an aluminium metal anode and chlorine cathode. They found a 1948 patent describing ionically conductive mixtures of AICI3 and 1-ethylpyridinium halides, mainly bromides [6]. Subsequently, the salt 1-butylpyridinium chloride/AlCl3 (another complicated pseudo-binary)... 

For a review of salts formerly thought of as low-temperature ionic liquids, see Mamantov, G., Molten salt electrolytes in secondary batteries, in Materials for Advanced Batteries (Murphy, D. W., Broadhead, J., and Steele, B.C. H. eds.). Plenum Press, New York, 1980,... 

Attention has been given for some time to the use of lithium alloys as an alternative to elemental lithium. Groups working on batteries with molten salt electrolytes that operate at temperatures of 400-450 °C, well above the melting point of lithium, were especially interested in this possibility. Two major directions evolved. One involved the use of lithium-aluminium alloys [5, 6], whereas another was concerned with lithium-silicon alloys [7-9]. 

The lithium-silicon system has also been of interest for use in the negative electrodes of elevated-temperature molten salt electrolyte lithium batteries. A composition containing 44 wt.% Li, where Li/Si=3.18, has been used in commercial... 

The molten salt electrolyte also contributes to the safety behavior of ZEBRA cells. The large amount of energy stored in a 700 g cell, which means about 30 kWh in a 300 kg battery, is not released suddenly as heat as be expected in a system with liquid electrodes such as the sodium sulfur cell. In the case of accidental destruction of ZEBRA cells, the sodium will react mainly with the molten salt, forming A1 sponge and NaCl. -The diffusion of the NaAICI ... 

Li-Al anodes have been combined in cells with CI2 in the Sohio Carb-Tek battery, operating with a molten salt electrolyte in the range of 400°-500°C. A porous carbon cathode and a BN separator were used. Addition of TeCla to the positive electrode increased the capacity in the 3.25-2.5V range. Although the battery presented many problems associated with the materials of the electrode, the casing and the seal, corrosion by CI2 being... 

Like the Li/FeSx system, which is presently the most advanced rechargeable battery system based on a molten salt electrolyte, the Na/S system is presently the most advanced rechargeable battery system based on a solid electrolyte (beta-alumina) It operates at about 300 C. 

Like fuel cells, batteries using molten salt electrolytes offer high performance. Molten salts have very high electrical conductivity, which permits the use of high current densities. Likewise, molten salts permit the use of highly reactive electrode materials, which cannot be used in aqueous electrolytes. For these reasons, batteries with molten salts offer very high specific energy (>100 Wh/kg). To... 

Sometimes other methods of classification are also used, for example, on the basis of the application (stationary or mobile batteries), shape (cylindrical, prismatic, disk-shape batteries), size (miniature, small-sized, m ium-sized, or large-sized batteries), electrolyte type (alkaline, acidic, or neutral electrolyte, with liquid or solid (solidified), or molten salt electrolyte), voltage (low voltage or high voltage batteries), electric power generation (low power or high power batteries), and so on. 

He has carried out researches in various fields of inorganic chemistry (coordination chemistry of 3d-metals, high-temperature chemistry of molten fluorides), physical chemistry (phase equilibria in molten salt systems), electrochemistry (thermodynamics of metal-electrolyte interface, electrodeposition of refractory and other metals from molten salts, lithium batteries and active materials for them) and, more recently, nanochemistry of inorganic oxide materials. 

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