Researchers are throwing salt at the flammability risks posed by some battery chemistries. The use of a salt-based solid diluent in the electrolyte of a sodium battery was demonstrated to enable inclusion of a single non-flammable electrolyte — trimethyl phosphate (TMP) — and stabilize the power unit.

Reliance on the sodium nitrate salt yields a battery that is more economical to manufacture relative to lithium-ion batteries. In addition to consuming no lithium, the battery designed by researchers from the University of Texas at Austin and the U.S. Argonne National Laboratory is also free of cobalt. The remainder of the unit is composed of 40% iron, 30% manganese and 30% nickel.

Illustration of the components with a sodium-metal battery after long-term cycling in carbonate-based electrolyte (left) and sodium nitrate-TMP electrolyte (right). Source: Nature Energy (2024). DOI: 10.1038/s41560-024-01469-y

The sodium battery retained 80% of its capacity over 500 cycles, matching the standard of lithium-ion batteries in smartphones. While the technique described in Nature Energy was applied to a sodium battery, the process could also translate to lithium-ion-based cells, albeit with different materials.