Design of Cellulosic Poly(Ionic Liquid)s with Hydrogen Bond/Ion Dual Regulation Mechanism for Highly Reversible Zn Anode†

Abstract

The unstable electrode/electrolyte interface with erratic zinc (Zn) deposition, severe dendritic growth and parasitic side reactions deteriorates the reversibility, tolerance and sustainability of aqueous Zn ion batteries (AZIBs). Herein, a imidazolium-based cellulosic poly(ionic liquid)s ([CellMim]+) additive with hydrogen bond/ion dual regulation mechanism for aqueous electrolyte was designed and prepared via a transesterification reaction by taking the particular solvent properties. The water-rich Zn anode interface significantly optimized by hydrogen bond (HB) formation and preferential adsorption of [CellMim]+. Additionally, the overfed Zn2+ ions are modulated by [CellMim]+ cations though electrostatic repulsion, fostering uniform Zn deposition and solid electrolyte interface (SEI). Notably, the Zn||Zn cells with [CellMim]+ modified Zn(OTf)2 electrolyte exhibit a long cycle life over 1800 h at 1 mA cm-2 and a high cumulative capacity of 3700 mAh cm-2 at 10 mA cm-2 with 56.9% Zn utilization rate (ZUR). Intriguingly, this electrolyte demonstrates a remarkable durability of 260 h at 8 mA cm-2 with 22.77% ZUR for a 9 cm2 pouch cell. These results highlight the great potential of cellulosic derivatives in battery applications and offer valuable insights into the design of sustainable aqueous electrolyte additives for AZIBs.