Water‐Repellent Ionic Liquid Skinny Gels Customized for Aqueous Zn‐Ion Battery Anodes

Abstract

Despite the enormous potential of aqueous zinc (Zn)‐ion batteries as a cost‐competitive and safer power source, their practical applications have been plagued by the chemical/electrochemical instability of Zn anodes with aqueous electrolytes. Here, ionic liquid (IL) skinny gels are reported as a new class of water‐repellent ion‐conducting protective layers customized for Zn anodes. The IL skinny gel (thickness ≈500 nm), consisting of hydrophobic IL solvent, Zn salts, and thiol‐ene polymer compliant skeleton, prevents the access of water molecules to Zn anodes while allowing Zn2+ conduction for redox reactions. The IL‐gel‐skinned Zn anode enables sustainable Zn plating/stripping cyclability under 90% depth of discharge (DODZn) without suffering from water‐triggered interfacial parasitic reactions. Driven by these advantageous effects, a Zn‐ion full cell (IL‐gel‐skinned Zn‐anode||aqueous‐electrolyte‐containing MnO2 cathode) exhibits high charge/discharge cycling performance (capacity retention ≈95.7% after 600 cycles) that lies beyond those achievable with conventional aqueous Zn‐ion battery technologies.

Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives

“…However, since the hydrophilic group of the polymer chain can absorb a large amount of water, the hydrogel electrolyte exhibits a conductivity close to that of a liquid. Meanwhile, water molecules are restricted instead of freely spreading, indicating that HER can be alleviated to a certain extent [ 164 ]. The fixed polymer chains play a vital role in ion transfer and Zn deposition.…”

Recent progress, mechanisms, and perspectives for crystal and interface chemistry applying to the Zn metal anodes in aqueous zinc‐ion batteries

“…What comes to the result is that the reversibility of Zn ion plating/stripping could achieve high reversion even as suffering from severe testing conditions like 90% depth of discharge, indicating that this work presents superior promise with high achievability (Figure 11C). 90 Recently, numerous functional electrolyte additives with a number of strengths have also assisted to regulate the interface chemistry of zinc electrolyte, which realizes reversible Zn 2+ plating/stripping by controlling the adsorption of zinc ions on the metal anode surface. Some effort has been taken to control the dendrite growth of Zn, attributed to the employment of several water-soluble organic additives.…”

“…Reproduced with permission. [90] Copyright 2021, Wiley change the environment of electrolyte filling with strongly polar solvation sheath and obviously tighten the water molecules, contributing to the space confinement and complete interaction attraction in zeolite pores. The simulation results reveal that zeolite molecules empower a uniform current density field which has a more delicate concentration gradient and less hydrogen evolution reaction (HER) possibility.…”

“…What comes to the result is that the reversibility of Zn ion plating/stripping could achieve high reversion even as suffering from severe testing conditions like 90% depth of discharge, indicating that this work presents superior promise with high achievability (Figure 11C). 90 …”

“…(C) The high reversibility of Zn ions plating/stripping under even severe conditions like 90% depth of discharge. Reproduced with permission [90] . Copyright 2021, Wiley…”