Grain-Oriented Dissolution Enabled by Hydrogel for Highly Reversible Zn Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc anodes suffer from poor reversibility due to dendritic growth and hydrogen evolution.
• Grain-oriented stripping is a promising but underexplored strategy to improve zinc anode performance.
• Understanding the mechanism of grain-oriented dissolution is crucial for developing stable zinc batteries.

Purpose of the Study:

• To design a multifunctional hydrogel for dynamic anode interface regulation.
• To achieve and elucidate the mechanism of grain-oriented zinc dissolution.
• To enhance the cycling stability and reversibility of zinc anodes.

Main Methods:

• Fabrication of a composite hydrogel using aramid nanofiber-polyvinyl alcohol (ANF-PVA) and calcium lignosulfonate (LS).
• In situ characterization of the anode-electrolyte interface.
• Electrochemical testing of Zn||Zn symmetric cells and Zn||I2 full cells under various conditions.

Main Results:

• The ANF-PVA-LS hydrogel promoted homogeneous electric field distribution and selective adsorption of LS onto Zn crystal planes.
• Grain-oriented zinc dissolution was successfully achieved, leading to uniform Zn deposition and suppressed side reactions.
• Zn||Zn symmetric cells demonstrated remarkable cycling stability (5000 h at ambient, 10900 h at -40 °C).
• Zn||I2 full cells showed high capacity retention (78.2% after 20,000 cycles), and pouch-type cells sustained 700 cycles.

Conclusions:

• The synergistic effect of ANF-PVA and LS enables controlled grain-oriented dissolution of zinc anodes.
• This approach significantly improves the reversibility and long-term stability of zinc anodes in energy storage devices.
• The developed hydrogel strategy offers a new pathway for high-performance and reliable zinc-based batteries.