Interfacial Electronic Nanoarchitectonics for Sustainable Zn─I₂ Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-iodine batteries (AZIBs) offer safety and cost benefits but suffer from poor kinetics, low conductivity, and polyiodide shuttling.
• Addressing these limitations is key to realizing the potential of AZIBs for practical applications.

Purpose of the Study:

• To design and investigate a novel heterostructure cathode for AZIBs to overcome performance limitations.
• To enhance electronic conductivity and regulate iodine electrochemistry through interfacial engineering.

Main Methods:

• Fabrication of a titanium nitride (TiN) and biomass-derived porous nitrogen-doped carbon (PNC) heterostructure cathode (PNC@TiN).
• Utilizing Density Functional Theory (DFT) calculations to understand interfacial electronic properties and bonding.
• Electrochemical testing of AZIBs with the PNC@TiN cathode, including cycling stability and rate performance.

Main Results:

• The PNC@TiN cathode demonstrated significantly enhanced electronic conductivity and improved iodine electrochemistry.
• DFT calculations revealed strong Ti-I bonding and suppressed polyiodide shuttling due to interfacial charge redistribution.
• AZIBs achieved a high reversible capacity of 166.9 mAh g⁻¹ after 21,000 cycles at 2.0 A g⁻¹ with 95.4% retention.
• Exceptional long-term durability was observed with <0.0003% capacity decay per cycle at 5.0 A g⁻¹.
• Assembled pouch cells showed practical viability with high capacity and negligible degradation.

Conclusions:

• The developed PNC@TiN heterostructure effectively enhances AZIB performance by optimizing interfacial electronic properties.
• This work highlights the importance of interfacial nanoarchitectonics for advanced energy storage materials.
• Repurposing biomass into advanced materials offers a sustainable strategy for next-generation batteries.