Regulating the Coordination Environment of H₂O in Hydrogel Electrolyte for a High-Environment-Adaptable and High-Stability Flexible Zn Devices

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries offer safe and cost-effective energy storage.
• Key challenges include zinc dendrite growth, hydrogen evolution, and limited temperature adaptability.

Purpose of the Study:

• To address limitations in aqueous zinc-ion batteries.
• To develop a hydrogel polymer electrolyte that regulates water molecule coordination.

Main Methods:

• A cross-linked hydrophilic hydrogel polymer electrolyte was synthesized using polyacrylamide, carboxymethyl cellulose, and ethylene glycol.
• The electrolyte disrupts water molecule hydrogen bonding, immobilizing water within the polymer matrix.
• Electrochemical performance was evaluated using Zn||Cu and Zn||Zn symmetric cells, and Zn||PANI devices across a wide temperature range.

Main Results:

• The hydrogel electrolyte effectively suppressed zinc dendrite growth and hydrogen evolution.
• Zn||Cu cells achieved 99.4% coulombic efficiency over 900 cycles.
• Zn||Zn symmetric cells demonstrated stable plating/stripping for over 1,700 hours.
• Zn||PANI devices showed exceptional cycling stability, exceeding 14,120 cycles at room temperature and 30,000 cycles at -40°C.

Conclusions:

• Regulating water molecule coordination in electrolytes is a viable strategy for advanced battery design.
• The developed hydrogel electrolyte significantly enhances the safety, stability, and environmental adaptability of zinc-ion batteries.