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.
This Brief includes a Technical Support Package (TSP).
CO2-Reduction Primary Cell for Use on Venus
(reference NPO-40892) is currently available for download from the TSP library.
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Overview
The document outlines a novel CO₂-reduction primary cell developed by NASA's Jet Propulsion Laboratory (JPL) for potential use in Venus landing missions. This innovative battery technology is designed to operate under the extreme conditions present on Venus, where surface temperatures are exceedingly high. The primary advantage of this battery is its significantly higher specific energy—estimated to be five to ten times greater than that of conventional high-temperature batteries. This characteristic makes it particularly suitable for long-duration missions, as it can function effectively without the need for cooling systems, which are typically required for traditional battery designs.
The battery utilizes the abundant carbon dioxide available in the Venusian atmosphere as a resource, allowing for a more sustainable and efficient energy storage solution. The design of the battery includes a porous catalytic cathode layer, a metal/metal oxide anode, and a solid oxide ion-conducting electrolyte, which together facilitate the electrochemical reactions necessary for energy generation. The document also describes the fabrication process of the battery cells, which involves preparing various layers in a green state followed by sintering or co-firing to achieve the desired density and performance characteristics.
In terms of testing and characterization, the document outlines a Phase I plan that includes evaluating cell voltage as a function of CO₂ partial pressure at temperatures around 460°C, examining the relationship between discharge current density and cell voltage, and assessing the design's impact on anode utilization. These tests aim to establish the technical feasibility of the battery and provide essential data for subsequent optimization and scaling efforts.
Phase II of the project will focus on design optimization, the fabrication of prototype cells, and the identification of manufacturing partners to facilitate production. The successful completion of Phase I is crucial for informing the next steps in the development process.
Overall, this CO₂-reduction primary cell represents a significant advancement in energy storage technology for space exploration, particularly for missions targeting Venus, where traditional battery systems would be inadequate. The document emphasizes the potential for this technology to enhance mission capabilities while reducing costs and complexity.
