Activating High-Loading Cathodes Using Percolative Graphite in Rechargeable Alkaline Zn-MnO₂ Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable alkaline Zn-MnO2 batteries are limited by the insulating nature of MnO2, necessitating conductive frameworks in cathodes.
• Current methods using high graphite content or high-surface-area carbons (e.g., Ketjen black, graphene) have drawbacks like reduced energy density or poor cycling stability.

Purpose of the Study:

• To develop a cost-effective conductive additive for MnO2 cathodes that balances conductivity and surface reactivity.
• To improve the performance of rechargeable alkaline Zn-MnO2 batteries, focusing on energy density and cycling stability.

Main Methods:

• Introduction of percolative graphite (PG) with moderate surface area as a conductive additive.
• Fabrication of electrodes using commercial γ-MnO2 and PG.
• Testing of pouch-cell level batteries in conventional alkaline electrolytes.

Main Results:

• Electrodes composed of γ-MnO2 and PG demonstrated practical energy densities.
• Superior cycling stability was achieved compared to conventional methods.
• PG effectively balanced conductivity and surface reactivity, mitigating side reactions.

Conclusions:

• Rational conductive network engineering is crucial for high-performance rechargeable Zn-MnO2 batteries.
• Percolative graphite (PG) offers a promising, cost-effective solution for enhancing Zn-MnO2 battery performance.
• The findings provide guidance for developing practical, high-energy-density alkaline Zn-MnO2 batteries.