Solvent control of water O−H bonds for highly reversible zinc ion batteries

Abstract

Aqueous Zn-ion batteries have attracted increasing research interest; however, the development of these batteries has been hindered by several challenges, including dendrite growth, Zn corrosion, cathode material degradation, limited temperature adaptability and electrochemical stability window, which are associated with water activity and the solvation structure of electrolytes. Here we report that water activity is suppressed by increasing the electron density of the water protons through interactions with highly polar dimethylacetamide and trimethyl phosphate molecules. Meanwhile, the Zn corrosion in the hybrid electrolyte is mitigated, and the electrochemical stability window and the operating temperature of the electrolyte are extended. The dimethylacetamide alters the surface energy of Zn, guiding the (002) plane dominated deposition of Zn. Molecular dynamics simulation evidences Zn2+ ions are solvated with fewer water molecules, resulting in lower lattice strain in the NaV3O8·1.5H2O cathode during the insertion of hydrated Zn2+ ions, boosting the lifespan of Zn|| NaV3O8·1.5H2O cell to 3000 cycles.

A Universal Descriptor in Determining H2 Evolution Activity for Dilute Aqueous Zn Batteries

“…In general, the less active a free water is, the fewer H bonds it has. [ 17,18,23,24 ] However, it is observed that when salt concentration increases, the number of H‐bonds in each water molecule falls, ruling out this explanation as well. Therefore, it appears that mysteries remain over the origin of HER suppression in conventional salt aqueous electrolytes.…”

Robust Solid Electrolyte Interphase Induced by Dication Deep Eutectic Electrolytes for Sustainable Zn Anodes

“…Regarding the desolvation of the Zn 2+ solvation structure, the discharging process generates more free-MSM and free-water molecules on the Zn anode surface. It is reasonably considered that the hydrogen bonding between MSM and water molecules can partially limit the rapid decomposition of water , and benefit the formation of effective SEI on the Zn electrode/electrolyte interface, ,, as well as the Na + can suppress the Zn dendrite deposition, which are all beneficial to the stability of Na–Zn hybrid batteries.…”

Study of a novel supramolecular hydrogel electrolyte for aqueous zinc ion batteries

“…35 Meanwhile, splendid interfacial compatibility between the electrode and hydrogel electrolyte is the precondition for maintaining long-term stable cycling performance. 36–38…”