Rechargeable Na–SO2 Battery with Ethylenediamine Additive in Ether‐Based Electrolyte

Rechargeable metal–SO₂ batteries have drawn tremendous attention because it can accelerate SO₂ fixation/utilization and offer high energy density. Herein, a rechargeable Na–SO₂ battery based on an ether‐based liquid electrolyte with an ethylenediamine (EDA) additive is realized via the reversible formation/decomposition of Na₂S₂O₄. Experimental investigations reveal that the EDA additive provides three benefits by simultaneously decreasing the overall electrode polarization, increasing the full discharge capacity, and improving battery cyclability. At a current density of 250 mA g^?1, the full discharge capacity of the battery with the EDA additive is more than twice of a similar system in the absence of EDA. In addition to the significantly enhanced capacity, the as‐assembled Na–SO₂ battery demonstrates excellent cyclic stability after 200 cycles, which is equivalent to a total duration of 1600 h. Moreover, the corrosion resistance of Na anode is strengthened with the aid of EDA in the SO₂‐containing liquid electrolyte. This work will pave the way for Na–SO₂ batteries as a promising battery technology toward both pollutant gas utilization and energy storage.