Comprehensive understanding of the roles of water molecules in aqueous Zn-ion batteries: from electrolytes to electrode materials

Abstract

Benefiting from the loose assembly conditions, high safety and environmental-friendly characteristics, rechargeable aqueous Zn-ion batteries (AZIBs) are attracting intensive attention. In fact, either the water in electrolyte or electrode materials...

Towards Understanding the Corrosion Behavior of Zinc‐Metal Anode in Aqueous Systems: From Fundamentals to Strategies

“…Since water is known to be the culprit of Zn corrosion and HER, it is logical to minimize the content of free and active water, therefore, the control of the solventized structure of Zn 2 + would be an ideal method. [51] The disadvantages caused by aqueous electrolytes have been reported to be mitigated by increasing the salt concentration or adding organic additives. The increase in salt concentration and the introduction of organic ligands disrupt the solventized structure of Zn 2 + and reduce the solvent water content (Figure 2f), but the excessive cost limits their development, consequently, the low-cost and efficient methods are required to be explored.…”

Strategies of regulating Zn2+solvation structures for dendrite-free and side reaction-suppressed zinc-ion batteries

“…169–172 If H 2 O molecules of [Zn(H 2 O) 6 ] 2+ can be replaced with other special molecules with a weak solvation effect (Fig. 7a), 173 the moderate de-solvation energy and uniform Zn deposition will be attained. Recently, various antisolvent strategies have been proposed including mainly the organic solvent additives and zinc-philic additives.…”

“…Different from the water-free all-solid-state electrolytes, the quasi-solid electrolytes are a type of gel electrolytes prepared by a polymer matrix containing Zn 2+ and a small amount of highly constrained water molecules (10 −4 –10 −3 S cm −1 ). 173 The gel electrolytes are usually prepared by chemical cross-linking of polymerized monomers and zinc-based salts, which can present excellent mechanical strength and simultaneously serve as separators in batteries. 92,243,244 On the one hand, the amount of free H 2 O molecules in gel electrolytes is greatly reduced when compared with aqueous electrolytes, thus effectively suppressing the H 2 O-induced parasitic reactions.…”

A Better Zn-Ion Storage Device: Recent Progress for Zn-Ion Hybrid Supercapacitors

“…Typically, the precipitation/dissolution processes of by-products like Zn 4 SO 4 (OH) 6 ·nH 2 O have been found in the system of ZIBs, especially in the Mn-based and V-based ZIBs [ 87 ]. The by-products with loose and porous layers will randomly form on the surface of bare Zn foil during charging/discharging processes, which leads to the uneven surface and Zn dendrite, then the poor cycling performance of ZIBs [ 194 , 195 ]. Therefore, the investigation of formation mechanisms of the by-products in ZHSCs is more necessary since the Zn anode of ZHSCs can be greatly consumed by the fast charging/discharging processes.…”