Design of cellulosic poly(ionic liquid)s with a hydrogen bond/ion dual regulation mechanism for highly reversible Zn anodes

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, an imidazolium-based cellulosic poly(ionic liquid) ([CellMim]⁺) additive with a hydrogen bond/ion dual regulation mechanism for aqueous electrolyte is designed and prepared via a transesterification reaction by considering particular solvent properties. The water-rich Zn anode interface is 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 a 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 mA h 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.