Indium-Mediated Glue-Like Interlayer Enables Stable High-Capacity Flexible Sodium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium metal anodes offer high theoretical capacity for next-generation batteries.
• Interfacial instability and sodium dendrite growth limit sodium metal anode practical applications.
• Developing stable interfaces is crucial for long-cycle-life sodium batteries.

Purpose of the Study:

• To engineer a stable, robust interlayer for sodium metal anodes.
• To mitigate interfacial degradation and dendrite formation during cycling.
• To enhance the overall performance and lifespan of sodium batteries.

Main Methods:

• In situ electrochemical conversion of copper indium disulfide (CuInS2) on a copper current collector.
• Fabrication of a three-dimensional composite interlayer (Na2S/Na5InS4/Cu).
• Evaluation of interfacial stability, Coulombic efficiency, and cycling performance in symmetrical and full cells.

Main Results:

• The composite interlayer exhibits strong interphase connections and mechanical stability.
• Achieved high Coulombic efficiency (>99.4%) and symmetrical cell stability (>2400 hours).
• Demonstrated excellent full cell cycling performance (95.3% capacity retention after 1000 cycles) and flexibility.

Conclusions:

• The developed glue-like interlayer effectively suppresses interfacial degradation and dendrite formation.
• This strategy significantly enhances the cycling stability and lifespan of sodium metal anodes.
• The robust interlayer enables high-performance and durable sodium batteries, including flexible pouch cells.