Developing “Really Cool” Low Temperature Molten Sodium Batteries

E. Spoerke
Sandia National Laboratories,
United States

Keywords: battery, energy storage


Safe, cost-effective, reliable batteries suitable for grid-scale implementation remain a critical need for our evolving grid infrastructure. Here, we describe a promising new class of low temperature molten sodium-halide batteries that operation near 100oC, a significant reduction from the ~300oC operating temperatures common to traditional molten sodium batteries. Realizing these low temperature systems promises reduced system costs and improved material lifetimes, but introduces new materials challenges ranging from molten salt catholyte chemistry to solid state separator performance and charge transfer at critical solid-liquid interfaces. Our developing design uses highly conductive, engineering NaSICON-based separators, a molten sodium anode, and an essential low melting-temperature inorganic sodium iodide (NaI)-based catholyte. These batteries exhibit high voltages (>3V) and stable, resilient cycling for more than 8 months. These batteries offer potential for large-scale, long-duration, and long-shelf life battery storage that will be key to developing new strategies for electrical reliability and resiliency. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.