DEAR0001669

To meet the grand challenges of climate change and energy independence we must replace fossil fuels with solar, wind, and storage. The sodium metal halide (NaMx) battery is a uniquely attractive solution for next-generation grid storage. The raw storage materials in the NaMx iron chemistry are table salt (NaCl) and iron, two of the most abundant and lowest-cost materials. In addition, the NaMx battery has a proven track record that displays excellent safety, high round-trip efficiency, competitive energy density, and long cycle and calendar life. The most disruptive and lowest-cost variant of the NaMx battery is the iron chemistry, but limited research on it has shown variable cycling performance. To bring the NaMx iron chemistry to market we must engineer robust cyclability of the iron chemistry, which will require an innovative materials R&D effort. By performing a systematic study using electrochemical measurements as well as materials characterization, we will isolate the factors that allow for long cyclability among temperature, particle size and preparation, and chemical additives. Our expertise makes us uniquely positioned for this task as well as for our parallel effort in scaling the manufacturing of NaMx batteries for the grid, allowing the U.S. to become the leader in this next-generation grid battery and achieving large-scale impact through renewables integration.