Labile Coordination Interphase for Regulating Lean Ion Dynamics in Reversible Zn Batteries.

The rechargeable Zn battery technology is plagued with limited reversibility on the anode. The issue is particularly exacerbated when using lean electrolytes, which compromises the economic advantages of zinc batteries for large-scale energy storage. In this paper, we report the development of a zinc-coordinated interphase that prevents chemical corrosion and provides protection for zinc anodes. The selective binding of Zn 2+  ions towards histidine and carboxylate ligands forms a coordination environment that offers high Zn 2+  affinity and fast Zn 2+  diffusion owing to its thermodynamic stability and kinetic lability. Both experiments and calculations suggest that the interphase mitigates side reactions and regulates the dendrite-free electrodeposition. Implementing this labile coordination interphase yields enhanced cycling at a high current density of 20 mA cm -2  with high reversibility of dendrite-free zinc plating/stripping for more than 200 hours. The reversibility was demonstrated in a Zn||LiMn 2 O 4 cell, which shows an energy density of 74.7 mWh g -1 and a Coulombic efficiency of 99.7% after 500 cycles. In addition, we demonstrate a lean-electrolyte full cell utilizing electrolyte of only 10 μL mAh -1 . This cell operates for an extended cycling life of 100 cycles, five times longer than the pristine Zn anodes. This provides an energy density that is significantly higher than that of commercial aqueous batteries. This work demonstrates a proof-of-concept design for utilizing labile coordination interphases on Zn anodes, offering an approach for low-electrolyte usage and the manufacture of high-energy-density batteries. This article is protected by copyright. All rights reserved.