feature of this battery is that co 2 has a high solubility in the battery solvent and a majority of the co 2 emitted on charging dissolves in the solvent fig1 shows the cycling performance of the sodium carbonate battery in terms of the change in capacity mamp hours and the voltage during charging and discharging the battery included a sodium metal anode and the cathode described above in sodium perchlorate dithylene glycol dimethylether pre saturated with co 2 starting from a charged state a voltage rises very quickly to the cell charging potential after which the sodium carbonate is converted to sodium ions and co 2 at point b charging is stopped and the battery is run in the discharging mode power generation at a voltage of approximately 2 1 v the capacity on discharge is approximately 1450 mah g and is some 450 mah g greater than that during charge this is achieved because of the additional pore volume the battery creates for solid deposits carbonates by starting with sodium carbonate in the cathode fig2 and fig3 show for comparison data from a li air battery with a carbon only cathode in terms of the capacity the na battery has twice the capacity of the li air battery fig4 and 5 show the cycling performance of calcium and potassium carbonate batteries respectively in terms of the change in capacity mamp hours and the voltage during charging and discharging however the k air.