Solid-state super ion conductors are key enabling elements for emerging energy storage technologies, such as sodium batteries. Here we describe the design and performance of emerging sodium battery chemistries including Na-NiCl2, Na-I2, and aqueous Na-based systems. Each of these technologies leverages the unique properties of the solid state electrolyte NaSICON (Na Super Ion CONductor). NaSICON provides exceptional low-to-intermediate temperature sodium ion conductivity, exhibits excellent chemical and mechanical stability, and can be produced in a range of form factors on an industrial scale. This material has facilitated the effective development of a suite of Na-based energy storage technologies that not only show promise for high capacity, high performance energy storage, but also operate at temperatures below 200 °C, utilize low cost components, and avoid the use of hazardous, explosive organic-based electrolytes. In order to expand the use of NaSICON outside nonaqueous energy storage systems, however, several “weak links” in the NaSICON phase chemistry and ceramic composition must be addressed. Here we describe our efforts to tune these characteristics during synthesis, successfully improving NaSICON’s stability in aggressive aqueous environments. Advancing the development of highly conductive, chemically stable solid state ion conductors stands to open the door to a range of innovative new sodium-based energy storage technologies needed to meet the ever-growing demand for safe, reliable, and effective electrical energy storage and delivery.
Sandia National Laboratories is a multi-mission 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.