Interlayer Sodium Plating/Stripping in Van der Waals-Layered Quantum Dot Superstructure.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Assembling quantum dots (QDs) into van der Waals (vdW)-layered superstructures is crucial for high-energy-density metal anodes.
• Designing such superstructures presents significant challenges in materials synthesis and assembly.

Purpose of the Study:

• To propose a novel chemical-vapor Oriented Attachment (OA) growth strategy for synthesizing vdW-layered carbon/QDs hybrid superlattice nanosheets.
• To investigate the structural properties and electrochemical performance of the synthesized Fe7S8@CNS material as a sodium metal anode host.

Main Methods:

• Utilized a chemical-vapor Oriented Attachment (OA) growth strategy to synthesize vdW-layered carbon/QDs hybrid superlattice nanosheets (Fe7S8@CNS).
• Characterized the superstructure's morphology, structure, and interlayer spacing (3 nm).
• Evaluated the electrochemical performance of Fe7S8@CNS as a host material for sodium metal anodes in half and full cells.

Main Results:

• Successfully synthesized Fe7S8@CNS with a large vdW gap, exhibiting quasi-atomic growth behavior.
• Demonstrated interlayer sodium plating/stripping behavior in Fe7S8@CNS, effectively suppressing sodium dendrite growth.
• Achieved stable cycling for 1000 hours with a high Coulombic efficiency (CE) of ~99.5% at 3.0 mA cm⁻² and 3.0 mAh cm⁻² in sodium metal anodes.
• Full cells (Na@Fe7S8@CNS||Na3V2(PO4)3) showed excellent cycle stability with 97% capacity retention after 1000 cycles at 1.0 A g⁻¹.

Conclusions:

• The developed OA growth strategy enables the creation of novel vdW-layered QDs superstructures.
• Fe7S8@CNS serves as an effective host material for sodium metal anodes, enhancing stability and suppressing dendrite formation.
• This work expands the family of vdW-layered QDs superstructures and their potential for advanced energy storage applications.