Alkaline earth batteries

Practical primary or secondary alkali-metal or alkaline-earth batteries can be made only if the dissolution of the anode by reactions (16.1) and (16.2) (and by other corrosion reactions) can be stopped. Since attacks both the electrolyte and the cathode, the electrolyte must be designed to contain at least one material that reacts rapidly with lithium (or with the alkali-metal anode) to form an insoluble SEI. On inert electrodes, the SEI is formed by reduction of the electrolyte. This type of electrode (completely covered by SEI), was named [1, 2] the SEI electrode. ... 

Because of the special stabiHty of the hexafluoroarsenate ion, there are a number of appHcations of hexafluoroarsenates. For example, onium hexafluoroarsenates (33) have been described as photoinitiators in the hardening of epoxy resins (qv). Lithium hexafluoroarsenate [29935-35-1] has been used as an electrolyte in lithium batteries (qv). Hexafluoroarsenates, especially alkaH and alkaline-earth metal salts or substituted ammonium salts, have been reported (34) to be effective as herbicides (qv). Potassium hexafluoroarsenate [17029-22-0] has been reported (35) to be particularly effective against prickly pear. However, environmental and regulatory concerns have severely limited these appHcations. 

The principal use of titanium sulfides is as a cathode material ia high efficieacy batteries (11). In these appHcations, the titanium disulfide acts as a host material for various alkafl or alkaline-earth elements. 

Nowadays, such hydride electrodes are used widely to make alkaline storage batteries which in their design are similar to Ni-Cd batteries but exhibit a considerably higher capacity than these. These two types of storage battery are interchangeable, since the potential of the hydride electrode is similar to that of the cadmium electrode. The metal alloys used to prepare the hydride electrodes are multicomponent alloys, usually with a high content of rare-earth elements. These cadmium-free batteries are regarded as environmentally preferable. 

The main reason for avoiding water as a solvent is the fact that the electrolysis of aqueous solutions of alkali and alkaline-earth metal salts commences at 1.7-2.0 volts (depending on the electrode material) and results in the evolution of O2 and H2. If the cell itself has a higher voltage, internal electrolysis can, but not always does occur, accompanied by the evolution of H2 and O2 and by self-discharge (117). However, this fact does not preclude attempts to create moist primary batteries with Li, Na or Ca, if the activity of H2O is kept sufficiently low. 

White [7] gives a general review that includes information about the preparation and purification of a variety of alkali and alkaline earth halide melts. Information about fluorides can also be found in an earlier review article by Bamberger [8]. Many different halide melts have been used as solvents for electrochemistry, and a complete discussion of all of these melts is outside the scope of this chapter. However, two systems that have generated continuous interest over the years are the LiCl-KC1 eutectic (58.8-41.2 mol%, mp = 352°C) [9] and the LiF-NaF-KF (46.5-11.5-42.0 mol%, mp = 454°C) also known as FLINAK [10]. The former is an electrolyte commonly used in thermal batteries, whereas the latter molten salt is of interest for refractory metal plating. 

Using the voltaic battery, Davy showed that the alkaline earths, like the caustic alkalis, were compounds containing oxygen and previously unknown metals. His characterization and naming of the alkaline earth metals followed his discovery of them barium, strontium, calcium, and magnesium are the names he invented for these metals. Like the names sodium and potassium, they are still in use today. 

Peled E. The electrochemical behavior of alkali and alkaline earth metals in nonaqueous battery systems - the solid electrolyte interphase model. J Electrochem Soc. 1979 126 2047-51. 

The electrodeposition of alkaline and alkaline earth metals has been investigated in the neutral (buffered) ionic liquids for the purpose of applying the ionic liquids to electrolytes of rechargeable batteries using these metals as anodes. However, the... 

Irrespective of these controversies, research in this intriguing area is crucially important from both fundamental and applied points of view. For instance, solid electrolytes and mixed conductors with mobile AP + cations may find applications in new types of rechargeable battery, and also in the aluminum industry alkaline-earth cation conductors may be used, in particular, for precise humidity control in gaseous media and for CO2 sequestration. This chapter includes a brief introduction to the field, with emphasis placed primarily on the authors own studies. Although many aspects of materials electrochemical behavior require detailed investigation and further validation, the chapter provides an excellent overview of the phases where multivalent cation conduction may occur. 

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