Simulating the Impact of Glassy Carbon Foam Electrodes on the Performance of Sodium Iodine Batteries

Abstract

We examined the influences of glassy carbon foam electrodes on the overall battery performance of secondary sodium iodine batteries. The battery combines a molten sodium anode and an iodine-based cathode with NaSICON serving as a ceramic separator. The battery system works at 100°C and is suitable for stationary energy storage. A long cycle life and good resource utilization are major concerns for establishing the proposed battery system. We employed a spatially resolved simulation approach to investigate the effects of foam electrodes with different porosities and cell sizes on the charging and discharging behavior. The spatially resolved model reflects species and mass transport as well as electrochemical processes and reactions in the positive half cell. An open-pored glassy carbon foam cathode structure shows improved utilizable capacity compared to a simpler two-dimensional electrode. Parameter studies of foam porosity and specific surface area indicate that porosity is the crucial parameter for achievable depth of discharge. We conclude that glassy carbon open-pored foam with preferably high porosity is a suitable material for cathode electrodes in sodium iodine batteries.

Molten sodium batteries: advances in chemistries, electrolytes, and interfaces

“…However, the cost limitations of V-based NFBs has motivated research into other redox couples. NFBs using aqueous bromine and iodine catholytes have been reported by Holzapfel et al and were able to achieve energy densities near 200 Wh kg −1 (Holzapfel et al, 2017;Gerbig et al, 2023). While roomtemperature molten alloys (Na-K and Na-Cs) are intriguing materials for molten Na batteries, they react aggressively with air and moisture (even more so than pure Na metal) and significant engineering controls will be necessary to successfully implement them in LMBs, especially if they are paired with an aqueous catholyte.…”