Ethylene Glycol‐Choline Chloride Based Hydrated Deep Eutectic Electrolytes Enabled High‐Performance Zinc‐Ion Battery

Abstract

Aqueous rechargeable zinc‐ion batteries (ARZIBs) are considered as an emerging energy storage technology owing to their low cost, inherent safety, and reasonable energy density. However, significant challenges associated with electrodes, and aqueous electrolytes restrict their rapid development. Herein, ethylene glycol‐choline chloride (Eg‐ChCl) based hydrated deep‐eutectic electrolytes (HDEEs) are proposed for RZIBs. Also, a novel V10O24·nH2O@rGO composite is prepared and investigated in combination with HDEEs. The formulated HDEEs, particularly the composition of 1 ml of EG, 0.5 g of ChCl, 4 ml of H2O, and 2 M ZnTFS (1‐0.5‐4‐2 HDEE), not only exhibit the lowest viscosity, highest Zn2+ conductivity (20.38 mS cm−1), and the highest zinc (Zn) transference number (t+ = 0.937), but also provide a wide electrochemical stability window (>3.2 V vs ZnǁZn2+) and enabledendrite‐free Zn stripping/plating cycling over 1000 hours. The resulting ZnǁV10O24·nH2O@rGO cell with 1‐0.5‐4‐2 HDEE manifests high reversible capacity of ≈365 mAh g−1 at 0.1 A g−1, high rate‐performance (delivered ≈365/223 mAh g−1 at 0.1/10 mA g−1) and enhanced cycling performance (≈63.10% capacity retention in the 4000th cycle at 10 A g−1). Furthermore, 1‐0.5‐4‐2 HDEE support feasible Zn‐ion storage performance across a wide temperature range (0–80 °C) FInally, a ZnǁV10O24·nH2O@rGO pouch‐cell prototype fabricated with 1‐0.5‐4‐2 HDEE demonstrates good flexibility, safety, and durability.

Cellulose Reinforced Eutectogel Electrolyte for Flexible Zinc-Ion Hybrid Supercapacitors

“…To overcome these challenges, recent attention has turned to eutectogel (ETG) electrolytes, which are based on deep eutectic solvents (DESs) . ETG electrolytes share the fundamental features of DESs including low cost, eco-friendly, superb thermal/chemical stability, nonflammability and ultrahigh safety. − Unfortunately, problems related to the preparation of ETG electrolytes still exist. First, the use of high water content DESs might cause Zn anode corrosion and side reactions .…”