Influence of Type of Carbon on ORR and OER for Sodium/Air Batteries

Sodium/air batteries have recently been studied as an alternative to lithium/air batteries. In spite of lower theoretical specific energy (1980Wh.kg-1 of sodium vs. 3600Wh.kg-1 of lithium), the abundance of sodium provides an advantage over lithium for its use as a metal anode.

Sodium/air batteries have a problem of the reversibility of electrode reactions similar to that of lithium/air batteries. Applying an appropriate material as a cathode can contribute to the generation of more reversible products on charge, increasing the cyclability and reducing ORR and OER overpotentials of the battery.

In this work, we studied ORR and OER in PEGDME500-based electrolytes, in the presence of Na+ ions, applying four types of carbon: glassy carbon, Black Pearl, SB and XC72R carbon. For this purpose, the three-electrode half-cell was used, utilizing the glassy-carbon electrode as the working electrode, which was tested as a stand-alone electrode, or alternatively was coated by the carbon, with a loading of ~100µg/cm2.

It was found that, except for glassy carbon, all the other types of carbon showed very close reduction and oxidation overpotentials. The highest reduction and oxidation currents were obtained with the use of Black-Pearl carbon.

Acknowledgments

This work was funded by ISAEF and BSF foundations