Regulating the coordination distance of solvation structure for high-performance aqueous zinc ion batteries

Despite rapid advancements, aqueous zinc-ion batteries (AZIBs) still face significant challenges, including hydrogen evolution reactions (HER) and uncontrolled growth of zinc dendrites. Herein, an efficient regulatory strategy of the coordination distance between H₂O and Zn²⁺ is proposed to alleviate the adverse reactions by introducing β-alanyl-L-histidine (LC) in ZnSO₄ (ZSO) electrolytes. The solvent sheath is reconstructed by using the strong coordination interaction between the LC and Zn²⁺, which causes an “expansion effect” within the solvation sheath, increases the distance between Zn²⁺ and H₂O from 2.09 Å to 2.13 Å and weakens Zn[sbnd]O interaction, facilitating the rapid dissociation of water molecule and expanding the electrochemical window. Moreover, the LC is preferentially adsorbed onto the anode to induce the uniform deposition of Zn²⁺. As a proof of concept, the Zn//Zn cell demonstrates an exceptionally long cycle life exceeding 2000 h at 10 mA cm⁻²/10 mAh cm⁻². Notably, even at a depth of discharge (DOD) of 50 %, it is capable of maintaining for over 350 h. The Zn//V₆O₁₃ full cell demonstrates an impressive capacity retention rate of up to 93.9 % after 1000 cycles at a current density of 5.0 A g⁻¹. This research provides a molecular engineering strategy aimed at the development of long-life AZIBs.