Eutectic Electrolytes with Doubly‐Bound Water for High‐Stability Zinc Anodes

Abstract

The aqueous zinc-ion battery has the advantages of environmental friendliness, safety, and reliability, which is expected to be used for large-scale energy storage. However, due to the high activity of water, the hydrogen evolution reaction (HER) easily occurs on the surface of the zinc anode during the charge-discharge process, which is accompanied by corrosion, by-products, and dendrite formation. Herein, a new-type eutectic electrolyte consisting of ZnCl 2 , tetramethylurea (TMU), and H 2 O with the optimal molar ratio of 1:3:1 (ZT-1) is developed for the high-stability zinc anodes. The H 2 O in this system is doubly bound through the coordination with Zn 2+ and the hydrogen bonding with TMU, thus leading to the greatly inhibited activity of H 2 O. In addition, the H 2 O and TMU are successively stripped during the desolvation process of ZnCl 2 (TMU)(H 2 O), followed by the deposition of [ZnCl 2 ] at the zinc interface. In this way, the tendency of HER, corrosion, dendrites, and by-products induced by the decomposition of H 2 O molecules at the zinc interface is minimized, enabling a much more stable plating/stripping process of Zn 2+ . Consequently, the Zn//Zn symmetric cell can stably cycle for >2000 h, while the Zn//Cu half cell can stably cycle 800 times with an average Coulombic efficiency of 99.5%.

A hydrated deep eutectic electrolyte with finely-tuned solvation chemistry for high-performance zinc-ion batteries

“…4e). 25,28,30,31,34,35,[39][40][41][42][43][44][45] To explore the feasibility of HDES electrolyte for practical use, Zn-NVO full cells were assembled. As shown in Fig.…”

Overcrowded Additive in Electrolyte and Crystalline Li2CO3 Artificial Solid Electrolyte Interphase on TiNb2O7 Anode Enable Long Lifespan Aqueous Lithium-Ion Batteries

“…1 H nuclear magnetic resonance (NMR) (Figure c) is employed to reveal the enhanced electrochemical performance of batteries, a strongest new H-bond interaction between 1,4DX and H 2 O is observed in THDX electrolyte. For free H 2 O, the 1 H signal at 3.49 ppm moved to 3.5 ppm after the addition of LiTFSI, indicating an extensive interaction between H 2 O and LiTFSI . However, after different concentrations of 1,4DX were added to the electrolyte, it further shifted to 3.56 and 3.57 ppm at 1 H, and a new H bond appeared at 3.35 ppm, indicating that the interaction between H 2 O and 1,4DX is stronger .…”

A Nature‐Inspired Separator with Water‐Confined and Kinetics‐Boosted Effects for Sustainable and High‐Utilization Zn Metal Batteries

“…After the introduction of HAP, the characteristic peak of the hydroxyl group shows a clear red shift from 3255 to 3190 cm −1 , implying that the formation of the intermolecular H‐bonds between the HAP and BC. [ 11a,14 ]…”