Acidity-Aided Surface Modification Strategy to Enhance In Situ MnO₂ Deposition for High Performance Zn-MnO₂ Battery...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc-manganese dioxide (Zn-MnO2) batteries are promising for large-scale energy storage due to cost-effectiveness and environmental friendliness.
• Key challenges include irreversible cathode reactions, limited cyclability, and electrolyte instability at high voltages.

Purpose of the Study:

• To investigate the charge-discharge mechanisms in Zn-MnO2 batteries.
• To elucidate the impact of pH and electrolyte concentration on MnO2/Mn2+ reactions for high-voltage operation.
• To improve cycling durability and overall battery performance.

Main Methods:

• In situ deposition of active β-MnO2 nanoflakes on a carbon-based current collector.
• Optimization of electrolyte pH and Mn2+ concentration.
• Integration of carbon current collectors with high structural defect density.
• Fabrication and testing of a flooded stack-type Zn-MnO2 battery prototype.

Main Results:

• A low pH, Mn2+-lean electrolyte enables extended cycling.
• The optimized design achieves a high discharge voltage of ≈2 V at 10 mA cm-2.
• The battery demonstrates an areal capacity of ≈2 mAh cm-2 with 100% capacity retention over 400 cycles.
• A cost-effective, cathode-free design was established.

Conclusions:

• Optimized electrolytes and defect-rich carbon current collectors significantly enhance Zn-MnO2 battery performance.
• The developed battery design offers a practical and scalable solution for energy storage.
• This research paves the way for more durable and efficient Zn-MnO2 batteries.