Inverse Solvation Configuration Induced by Organic Small‐Molecule Spatially‐Confined Coordination Enables Highly Reversible Zinc Batteries

Abstract Despite the cost and safety advantages of zinc‐ion batteries (ZIBs), they still suffer from poor reversibility of Zn anodes in aqueous electrolytes, particularly under harsh conditions such as extreme temperatures and high depth of discharge. Herein, a low‐concentration small‐molecule spatially confined coordination electrolyte (0.45 m Zn(BF 4 ) 2 ·xH 2 O–THF) is developed that reconstructs the Zn 2 ⁺ solvation structure, forming a unique “inverse solvation configuration” rich in organic small molecules, thereby accelerating the de‐solvation process of Zn 2+ and forming a favorable and thin (≈50 nm) organic–inorganic hybrid SEI layer to achieve high interfacial stability. Concurrently, tetrahydrofuran can alter the inherent hydrogen bonding network and reduce the freezing point, ensuring stable solvation structure under harsh low‐temperature conditions. As a result, the Zn || Zn symmetrical cells can be cycled for over 7000 h at low temperature, and the Zn || PANI full cells demonstrate impressive cycling stability over 18 000 cycles (−40 °C) with a capacity retention rate ≈100%. Importantly, even at a high discharge depth of 60%, Zn || Zn symmetrical cells can still maintain stable plating/stripping behavior over 3500 h. This work provides new insights for the electrolyte design of high‐performance ZIBs.