High‐Reversibility Sulfur Anode for Advanced Aqueous Battery
Qianru Chen, Junnan Hao, Shaojian Zhang, Zhihao Tian, Kenneth Davey, Shi‐Zhang Qiao
Abstract
Abstract Despite being extensively explored as cathodes in batteries, sulfur (S) can function as a low‐potential anode by changing charge carriers in electrolytes. Here, a highly reversible S anode that fully converts from S 8 0 to S 2− in static aqueous S–I 2 batteries by using Na + as the charge carrier is reported. This S anode exhibits a low potential of −0.5 V (vs standard hydrogen electrode) and a near‐to‐theoretical capacity of 1404 mA h g −1 . Importantly, it shows significant advantages over the widely used Zn anode in aqueous media by obviating dendrite formation and H 2 evolution. To suppress “shuttle effects” faced by both S and I 2 electrodes, a scalable sulfonated polysulfone (SPSF) membrane is proposed, which is superior to commercial Nafion in cost (US$1.82 m −2 vs $3500 m −2 ) and environmental benignity. Because of its ultra‐high selectivity in blocking polysulfides/iodides, the battery with SPSF displays excellent cycling stability. Even under 100% depth of discharge, the battery demonstrates high capacity retention of 87.6% over 500 cycles, outperforming Zn–I 2 batteries with 3.1% capacity under the same conditions. These findings broaden anode options beyond metals for high‐energy, low‐cost, and fast‐chargeable batteries.