Close‐Loop Cathode Chemistry Enables Self‐Rejuvenating Aqueous Zn–Te Batteries Compromised by Non‐Equilibrium Redox Pathways

Abstract

Abstract Tellurium (Te) emerges as an alluring cathode material for aqueous zinc‐ion batteries, boasting an unrivaled six‐electron‐transfer capacity (1260 mAh g −1 and 7829 mAh cm − 3 ). However, the battery performance and cycling stability are severely degraded by inherent TeO x ·H 2 O(aq) shuttle arising from proton‐tunneling‐induced non‐equilibrium electrochemical hydrolysis, where proton‐coupled electron transfer (PCET) dominates. In this work, a rejuvenation of dead Zn–Te batteries is demonstrated based on a close‐loop chemistry via employing organic triethylsulfonium iodide (C 6 H 15 SI, TESI). The triiodide anions (I 3 − ) are found to reduce dissolved TeO x ·H 2 O(aq.) with thermodynamic favorability to revitalize Te cathode, meanwhile, generated I 2 is recycled back into the electrolyte by reacting with iodide anions. Simply left resting for 12 h, a completely degraded Zn–Te cell (1500 cycles) recovered 94.3% of its initial capacity (465 mAh g −1 ). Furthermore, TES + is found to promote an anode solid electrolyte interphase via detaching ethyl. The functional layer efficaciously prevented anode passivation caused by tellurium‐shuttling and facilitated efficient zinc‐ion transfer to achieve dendrite‐free zinc anode. This loop chemistry not only extends the lifespan of batteries but also enables the reuse of materials, potentially reducing the overall cost of battery production and resource consumption.