Silver oxide secondary batteries electrodes

The rechargeable silver oxide batteries are noted for their high specific energy and power density. The high cost of the silver electrode, however, has limited their use to applications where high specific energy or power density is a prime requisite, such as lightweight medical and electronic equipment, submarines, torpedoes, and space applications. The characteristics of the silver oxide secondary batteries are summarized in Table 33.1. 

Silver oxide/zinc can be manufactured in rechargeable cells with free potassium hydroxide electrolyte and pasted rectangular electrodes. Such cells are expensive but have a good energy density compared with Pb/acid or Ni/Cd (70 Wh kg ) and are also capable of high discharge rates for short periods. Other alkaline secondary batteries which have been manufactured include NiO(OH)/Zn, NiO(OH)/Fe and Ag2 0/Cd. 

Zinc electrodes for secondary silver-zinc batteries are made by one of three general methods the dry-powder process, the slurry-pasted process, or the electroformed process The active material used in any of the processes for the manufacture of electrodes is a finely divided zinc oxide powder, USP grade 12. 

The electrolyte used in secondary silver cells is generally an aqueous solution (35 to 45% concentration) of potassium hydroxide (KOH). Lower concentrations of electrolyte provide lower resistivity and thus a higher voltage output under load as weU as a lower freezing point. Concentrations below 45% KOH, however, are more corrosive to the ceUulosic separators typically used in silver-based batteries and are not used for extended wet-hfe applications. Table 33.3 depicts the critical parameters of various KOH solutions. Various additives such as zinc oxide, lithium hydroxide, potassium fluoride, potassium borate, tin, and lead have been used to reduce the solubility of the zinc electrode. " ... 

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