Selenium‐Anchored Chlorine Redox Chemistry in Aqueous Zinc Dual‐Ion Batteries

Abstract Chlorine‐based batteries with Cl⁰ to Cl⁻ redox reaction (ClRR) are promising for high‐performance energystorage due to their high redox potential and large theoretical capacity. However, the inherent gas–liquid conversion feature of ClRR together with poor Cl fixation can cause Cl₂ leakage, reducing battery reversibility. Herein, we utilize a Se‐based organic molecule, diphenyl diselenide (di‐Ph‐Se), as the Cl anchoring agent and realize an atomic level‐Cl fixation through chalcogen‐halogencoordinating chemistry. The promoted Cl fixation, with two oxidized Cl⁰ anchoring on a single Ph‐Se, and the multivalence conversion of Se contributeto a six‐electron conversion process with up to 507 mAh g⁻¹ and an average voltage of 1.51 V, as well as a high energy density of 665 Wh Kg⁻¹. Based on the superior reversibility of thedeveloped di‐Ph‐Se electrode with ClRR, a remarkable rate performance (205 mAh g⁻¹ at 5 A g⁻¹) and cycling performance (capacity retention of 77.3 % after 500cycles) are achieved. Significantly, the pouch cell delivers a record arealcapacity of up to 6.87 mAh cm⁻² and extraordinary self‐discharge performance. This chalcogen‐halogen coordination chemistry between the Se electrode and Cl provides a new insight for developing reversible and efficientbatteries with halogen redox reactions.