Ion‐Framework Electrolyte Featured Zinc‐Ion Transport for Solvent and Interphasial Co‐Passivation

Abstract

Abstract The rapid application of zinc‐ion (Zn 2+ ) energy storage lacks favorable solvation structures to simultaneously form inert electrolyte environments and robust solid electrolyte interphase (SEI), which means that Zn 2+ devices cannot synchronously against the side reactions, Zn dendrites and narrow electrochemical stability windows, further hindering their wide operative voltage window and ultra‐long service life. Here, ion‐framework electrolytes are designed by using large‐sized inert‐ammonium salts as the main solute. The ion framework, assembled from ultra‐large solvation ion clusters containing large tetraethylammonium cations, large anions, and abundant solvents via electrostatic interactions, not only forms suitable channels for Zn 2+ transport but also constrains free solvents to passivate their electrochemical activity, achieving an ultra‐wide electrochemical stability window about 3.72 V. More importantly, the enrichment of the ion framework at Zn interface generates a homogenous SEI with the dense polymer‐inorganic hybrid structure to passivate the interphasial chemistry, which eliminates the Zn dendrites and side reactions. Therefore, Zn anode using this electrolyte achieves the ultra‐long cycling stability of 8,150 h, and Zn metal||activated carbon capacitors exhibit a high operative voltage (0–2.1 V) and ultra‐long cycle life (≈170,000 cycles at 10 A g −1 ). This electrolyte design principle is promising for addressing the typical challenges in other metal‐ion systems.