A document proposes a CO2-reduction primary electrochemical cell as a building block of batteries to supply electric power on the surface of Venus. The basic principle of the proposed cell is similar to that of terrestrial Zn-air batteries, the major differences being that (1) the anode metal would not be Zn and (2) CO2, which is about 96.5 mole percent of the Venusian atmosphere, would be used, instead of O2, as the source of oxygen. The cell would include a solid electrolyte that could withstand operation at a temperatures as high as 1,000 °C and, hence, could withstand operation at the Venusian surface temperature of ≈460 °C.

Electrical energy would be generated by a combination of (1) electrochemical reduction of CO2 at the cathode and (2) oxidation of a suitable metal to metal oxide at the anode. Unlike some other types of cells that have been considered for use on Venus, the CO2-reduction cell could operate for a long time, without need for cooling. If the anode metal were Mg, then the performance could be impressive: The specific energy of the proposed cell has been estimated theoretically to be 3.46 W·h/g.

This work was done by William West, Jay Whitacre, and Sekharipuram Narayanan of Caltech for NASA’s Jet Propulsion Laboratory.