Kosmotropic Anions‐Intensified Proline Additive Enabling Highly Stable Zn Anodes

Abstract Despite the conspicuous merits of Zn metal anodes, the commercialization of Zn anode‐based electrochemical energy storage devices is still constrained by uncontrollable dendrite growth and serious parasitic reactions. Herein, an innovative strategy of employing kosmotropic anions‐intensified proline additive to regulate the Zn 2+ solvation structure and manipulate the Zn deposition interface, thus achieving highly stable Zn anodes, is proposed. The key to this strategy lies in ingeniously utilizing kosmotropic SO 4 2− anions to enhance the affinity of proline adsorption layer on the Zn anodes and weaken the solvation of Zn 2+ . Consequently, Zn anodes in the proline‐containing ZnSO 4 (ZnSO 4 ‐proline) electrolyte deliver a remarkable lifespan over 2600 h at 1.0 mA cm −2 and 1.0 mAh cm −2 . Even under a harsh plating/stripping condition (10 mA cm −2 and 10 mAh cm −2 ), Zn anodes in the ZnSO 4 ‐proline electrolyte stably operate for 650 h. Meanwhile, the Coulombic efficiency of Zn plating/stripping in the designed electrolyte is as high as 99.9% over 1100 cycles. The ZnSO 4 ‐proline electrolyte endows Zn‐ion batteries and Zn‐ion hybrid capacitors with notably optimized long‐term cycling stability. This work is expected to be of immediate benefit to design low‐cost Zn‐based energy storage systems with ultra‐long lifespan.