Triflate anion chemistry for enhanced four-electron zinc–iodine aqueous batteries

Abstract

The I+ hydrolysis, sluggish iodine redox kinetics and the instability of Zn anodes are the primary challenges for aqueous four-electron zinc–iodine batteries (4eZIBs). Herein, the OTf− anion chemistry in aqueous electrolyte is essential for developing advanced 4eZIBs. It is elucidated that OTf− anions establishes weak hydrogen-bond (H-bond) with water to stabilize I+ species, while concurrently optimizing a water lean Zn2+ coordination structure to mitigate Zn dendrite and corrosion. Moreover, the interaction of OTf− anion with iodine species results in the prolonged equilibrium average intermolecular bond length of iodine species, facilitating 4e redox kinetics of iodine with improved reversibility.