Recent Progress on Modulating the Electrochemical Stability Window for Zn Aqueous Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc aqueous batteries (ZABs) offer safe, low-cost, and sustainable energy storage.
• Practical ZAB deployment is limited by water's narrow electrochemical stability window (ESW) and zinc anode degradation.

Purpose of the Study:

• To review and critically examine recent advances in ESW engineering for ZABs.
• To provide a coherent toolkit for modulating ZAB ESW by comparing diverse approaches.

Main Methods:

• Reshaping bulk solvation (e.g., concentrated electrolytes, hydrate-melts).
• Regulating proton activity (e.g., pH-buffered electrolytes).
• Confining water (e.g., hydrogels, "soggy-sand" media).
• Building protective interphases and hydrophobic interfaces (e.g., SEI, surfactants).

Main Results:

• Anion-rich, water-poor solvation shells suppress hydrogen and oxygen evolution.
• Various strategies extend the practical ESW by shielding water kinetically.
• Mechanistic commonalities across different approaches are identified.

Conclusions:

• ESW engineering is crucial for advancing high-voltage, long-life ZABs.
• Combining electrolyte modification, interphase engineering, and cell design is promising.
• Further research is needed to approach the intrinsic limits of aqueous electrochemistry.