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| Figure 15-4 Chemical actions of alkali cell: (A) Discharged, and (B) charged. |

| the same ultimate recombination. The chemical reactions are represented by the same equations as those for discharge except that they are read in reverse order. The overall chemical equation would be read from right to left. |

| The effect of the reactions can be described as a transfer of oxygen from the negative plate to the positive plate during the charging operation and the reverse transfer during the discharging operation. |

| The lithium hydroxide catalyst aids but does not take part in the reaction itself. For one thing, it considerably increases battery capacity. Furthermore, it acts as a preservative of ferrous metals and makes possible the use of steel for the structural parts of the cell, both of which services materially increase the life of the battery. |

| In a modification of the Edison alkaline cell, the iron is replaced with cadmium and the potassium hydroxide electrolyte takes the form of a paste rather than a liquid. The nickel cadmium or Nicad battery overcomes some of the disadvantages of the Edison battery because the cells are hermetically sealed and require no maintenance or tests. It will also deliver the same load current as a lead-acid battery of the same specification but for twice the length of time. |

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