Aluminum Primary Batteries

Aluminum is directly applied in its metallic form when it serves as battery anode. The battery concepts considered are in general single-use types (primary batteries). The most developed systems belong to the metal-air batteries, using the reduction of atmospheric oxygen as the cathode reaction, e.g., (-) A1 / KOH / 02 (+) or (-) A1 / seawater / 02 (+). The main discharge reactions are ... 

Magnesium and aluminum are attractive candidates for use as anode materials in primary batteries. As shown in Table 1.1, Chap. 1, they have a high standard potential. Their low atomic weight and multivalence change result in a high electrochemical equivalence on both a gravimetric and a volumetric basis. Further, they are both abundant and relatively inexpensive. 

Aluminum active primary batteries were never produced commercially. While the experimental aluminum batteries delivered a higher energy output than conventional zinc batteries, anode corrosion, causing problems on intermittent and long-term discharges and irregularities in shelf Ufe, and the voltage-delay problem restrained commercial acceptance. Aluminum/ air batteries are covered in Chap. 38. 

Zinc—bromine storage batteries (qv) are under development as load-leveling devices in electric utilities (64). Photovoltaic batteries have been made of selenium or boron doped with bromine. Graphite fibers and certain polymers can be made electrically conductive by being doped with bromine. Bromine is used in quartz—haUde light bulbs. Bromine is used to etch aluminum, copper, and semi-conductors. Bromine and its salts are known to recover gold and other precious metals from their ores. Bromine can be used to desulfurize fine coal (see Coal conversion processes). Table 5 shows estimates of the primary uses of bromine. 

The electrochemical conversions of solid compounds and materials that are in direct contact with electrolyte solutions or liquid electrolytes (ionic liquids), belong to the most widespread reactions in electrochemistry. Such conversions take place in a wide variety of circumstances, including the majority of primary and secondary batteries, in corrosion, in electrochemical machining, in electrochemical mineral leaching, in electrochemical refining (e.g., copper refining), and in electrochemical surface treatments (e.g., the anodization of aluminum). 

Both primary and secondary metal-air batteries have been considered for mobile applications. The metal negatives involve mainly zinc and iron, in rechargeable, and aluminum, in primary systems. 

New lithium-based and the more conventional Ni-Zn batteries may eventually replace lead-acid batteries as new technology and advanced manufacturing techniques reduce their costs. Metal-air batteries, both rechargeable (zinc) and nonrechargeable fuel-cell types (aluminum), may ultimately be successful as an economical primary source for short-trip transportation. The demand for increasing electronic equipment will require increased auxiliary power, which may be fulfilled by improved lithium-based and Ni-Zn systems. 

Electrolytic gas evolution is a significant and complicated phenomenon in most electrochemical processes and devices. In the Hall process for aluminum production, for example, bubbles evolved on the downward-facing carbon anodes stir the bath and resist the current, both of which directly affect the heat balance and the cell voltage. Bubbles appear as a result of primary electrode reactions in chlorine and water electrolysis, and as the result of side reactions in the charging of lead-acid batteries and some metal electrowinning. Stirring of the electrolyte by gas evolution is an important phenomenon in chlorate production. Electrolytically evolved bubbles have also been used in mineral flotation. Relatively few major electrochemical processes do not evolve gas. 

Electrolytic cells, cells that use electricity to produce a desired redox reaction, are used extensively in our society. Rechargeable batteries are a primary example of this type of cell, but there are many other applications. Ever wonder how the aluminum in that aluminum can is mined Aluminum ore is primarily aluminum oxide (AI2O3). Aluminum metal is produced by reducing... 

Experimental work on Al/MnOj primary or dry batteries was concentrated on the D-size cylindrical battery using a construction similar to the one used for the Mg/Mn02 battery (Fig. 9.3). The most successful anodes were made of a duplex metal sheet consisting of two different aluminum alloys. The inner, thicker layer was more electrochemically active, leaving the outer layer intact in the event of pitting of the inner layer. The cathode bobbin consisted of manganese dioxide and acetylene black, wetted with the electrolyte. Aqueous solutions of aluminum or chromium chloride, containing a chromate inhibitor, were the most satisfactory electrolytes. 

Elements from column III which have been studied for Li-ion anodes are essentially aluminum (Al) and gallium (Ga). Although the boron-lithium phase diagram shows several compounds [122], Li poorly reacts with B at room temperature [123]. Actually, B or rather Li-B alloys have been studied for application in the so-called thermal batteries, which are primary devices working at high temperature (350-450 °C) with molten salt electrolytes [124, 125]. 

Besides aluminum pouch film, plastic materials can also be cast into different shapes as cases for lithium-ion batteries [4]. This is mainly applied to lithium-ion batteries of large capacity, which mainly use LiFeP04 as the positive electrode material. Usually, PP or PET is the primary material. In order to enhance its strength, some inert fillers can be added, and some metallic reinforcing parts can also be attached. 

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