Development of High Surface Area Carbon Electrodes for the Bromine Reactions in H2-Br2 fuel Cells

The H₂-Br₂ system is considered as one of the viable options for  large scale electrical energy storage due to faster H₂ and Br₂ reaction kinetics, low cost, and high round-trip efficiency. Since the bromine reactions in this fuel cell system do not need any precious metal catalysts, plain porous carbon paper can be used as an electrode material. However, these porous carbon electrodes have low surface area and hence multiple electrode layers are employed to improve the active surface area. While the active surface area is enhanced by using multiple electrode layers, it could lead to mass transport limited performance at higher current densities. To overcome this problem, porous carbon electrodes with multi-wall carbon nanotubes grown directly on their surface were developed. The cross section of a carbon nanotube based electrode is shown in Figure 1. In this presentation, we will discuss the synthesis and characterization of carbon nanotube based electrodes as well as their durability and actual performance in a H₂-Br₂  fuel cell. Also, the advantages of these carbon nanotube based electrodes over conventional porous carbon electrodes will be highlighted.

Acknowledgements

This work was funded by NSF through grant number EFRI-1038234 and DOE/ARPA-E under award number DE-AR0000262.

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