air battery

An air battery is a type of primary cell that uses air, water, and aluminum chunks to produce electrical energy. The $\mathrm{Al}(\mathrm{OH}){}_3(\mathrm{s})$ precipitate has to be collected and converted back to $\mathrm{Al}(\mathrm{s})$ at a facility.

$$\begin{array}{rlrl}(\times 4)\text{ Anode:}& & \mathrm{Al}(\mathrm{s})+4\mathrm{OH}{}^{-}(\mathrm{aq})& \to [\mathrm{Al}(\mathrm{OH}){}_4]{}^{-}(\mathrm{aq})+3\mathrm{e}{}^{-}\\ (\times 3)\text{ Cathode:}& & \mathrm{O}{}_2(\mathrm{g})+2\mathrm{H}{}_2\mathrm{O}(\mathrm{l})+4\mathrm{e}{}^{-}& \to 4\mathrm{OH}{}^{-}(\mathrm{aq})\end{array}$$