Molten Sodium Batteries

The rapid growth in demand for electrical energy storage in the twenty-first century has renewed interest in molten sodium batteries for safe, reliable, typically large format storage. These batteries take advantage of globally abundant sodium as a key active material in the system, employing solid-state ceramic separators, and utilizing several different cathode chemistries in battery design. This chapter introduces these battery systems, primarily focused on sodium-sulfur and sodium-nickel chloride (ZEBRA) batteries. It describes the materials chemistries of the anodes, the separators, and the cathodes of these batteries, highlighting both virtues and challenges to be overcome with further research and development. It further highlights new chemistries and materials that may enable key innovations to battery design that will lower the operational temperatures, improve safety, and drive down limiting costs of these systems. Ultimately, improvements resulting from these research and development efforts are expected to expand an already growing global market for large-scale molten sodium batteries.