A Foldable Aqueous Zn-Ion Battery with Gear-Structured Composite as Freestanding Cathode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Flexible batteries are crucial for wearable electronics in health, fitness, and military applications.
• Existing flexible batteries often lack durability and self-healing capabilities.

Purpose of the Study:

• To develop a highly flexible and self-healing zinc-ion battery with a free-standing cathode.
• To evaluate the battery's performance under mechanical stress, including folding, cutting, and twisting.

Main Methods:

• Fabrication of a 3D gear-like NH4V4O10@C composite cathode on carbon paper.
• Utilizing an aqueous hydrogel electrolyte with high tensile strain properties.
• Testing battery capacity retention, Coulombic efficiency, and self-healing after mechanical deformation.

Main Results:

• The battery retained 102.4 mAh/g capacity after 60 folds (180°).
• The hydrogel electrolyte exhibited 580% tensile strain.
• The battery showed capacity retention over 100 mAh/g and >99.8% Coulombic efficiency after cutting and twisting, indicating self-healing.

Conclusions:

• The gear-like cathode design enhances volume accommodation and ion conductivity.
• The flexible, self-healing zinc-ion battery offers a practical power solution for portable electronics under mechanical stress.