Button Batteries Although some of the small button batteries used to power watches, calculators, and cameras are miniature alkaline cells, most are based on a completely different chemistry. In these batteries, the anode is a zinc–mercury amalgam rather than pure zinc, and the cathode uses either HgO or Ag2O as the oxidant rather than MnO2 (part (b) in the Figure below). The cathode and overall reactions and cell output for these two types of button batteries are as follows: The major advantages of the mercury and silver cells are their reliability and their high ratio. These factors make them ideal for applications where small size is crucial, as in cameras and hearing aids. The disadvantages are the expense and the environmental problems caused by the disposal of heavy metals, such as Hg and Ag. Lithium–Iodine Battery None of the batteries described is actually They all contain small amounts of liquid water, “dry.” which adds significant mass and causes potential corrosion problems. Consequently, substantial effort has been expended to develop water-free batteries. One of the few commercially successful batteries is the lithium–iodine batteryA battery that I , consists of an anode of lithium metal and a cathode containing a solid complex of with a layer of 2 Li solid LiI in between that allows the diffusion of ions.. The anode is lithium metal, and the + cathode is a solid complex of I2. Separating them is a layer of solid LiI, which acts as the electrolyte by allowing the diffusion of Li+ ions. The electrode reactions are as follows:
Button Batteries Although some of the small button batteries used to power watches, calculators, and cameras are miniature alkaline cells, most are based on a completely different chemistry. In these batteries, the anode is a zinc–mercury amalgam rather than pure zinc, and the cathode uses either HgO or Ag2O as the oxidant rather than MnO2 (part (b) in the Figure below). The cathode and overall reactions and cell output for these two types of button batteries are as follows: The major advantages of the mercury and silver cells are their reliability and their high ratio. These factors make them ideal for applications where small size is crucial, as in cameras and hearing aids. The disadvantages are the expense and the environmental problems caused by the disposal of heavy metals, such as Hg and Ag. Lithium–Iodine Battery None of the batteries described is actually “dry.” They all contain small amounts of liquid water, which adds significant mass and causes potential corrosion problems. Consequently, substantial effort has been expended to develop water-free batteries. One of the few commercially successful batteries is the lithium–iodine batteryA battery that consists of an anode of lithium metal and a cathode containing a solid complex of I 2 , with a layer of solid LiI in between that allows the diffusion of Li + ions.. The anode is lithium metal, and the cathode is a solid complex of I2. Separating them is a layer of solid LiI, which acts as the electrolyte by allowing the diffusion of Li+ ions. The electrode reactions are as follows:
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