Stable Sodium Metal Anode Enabled by an Interface Protection Layer Rich in Organic Sulfide Salt

Abstract

Sodium (Na) metal is considered as a promising anode candidate for large-scale energy storage systems because of its high theoretical capacity and low electrochemical redox potential. However, Na anode suffers from a few challenges, such as the dendrite growth and severe parasitic reactions with electrolytes, which greatly hinder its practical applications. In this work, we demonstrate that an organosulfur compound additive (tetramethylthiuram disulfide) provides a facile and promising approach to overcome the above challenges in carbonate-based electrolytes. This unique organosulfur additive can in situ form a stable interfacial protection layer rich in organic sulfide salts on the sodium metal surface during cycling, leading to a stable stripping/plating cycling. Additionally, a cycling Coulombic efficiency of 94.25% is achieved, and the full battery using Prussian Blue as a cathode delivers a reversible capacity of 86.2 mAh g–1 with a capacity retention of 80% after 600 cycles at 4 C.