Communication—Molten Amide-Hydroxide-Iodide Electrolyte for a Low-Temperature Sodium-Based Liquid Metal Battery

Abstract

The low cost and high abundance of sodium make it an attractive choice for the negative electrode in a liquid metal battery. However, sodium has not found use in this application owing to the high solubility of the metal in its molten halides which results in poor coulombic efficiency and an unacceptably high rate of self discharge. In this work, we investigated the electrochemical behavior of the ternary eutectic of NaNH[subscript 2], NaOH and NaI (m.p. 127°C) and evaluated its usefulness as an electrolyte for sodium-based liquid metal batteries. Cyclic voltammetry revealed an electrochemical window of 1.3 V at 180°C. The anodic limit is set by the oxidation of amide anions to form hydrazine gas.