Functionalized Halloysite Scaffold Controls Sodium Dendrite Growth.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sodium metal anodes are promising for low-cost rechargeable batteries.
• Sodium dendrite growth hinders the commercialization of sodium metal anodes.

Purpose of the Study:

• To develop a novel strategy for achieving uniform sodium deposition and suppressing dendrite growth in sodium metal anodes.
• To utilize halloysite nanotubes (HNTs) as insulated scaffolds and silver (Ag) nanoparticles as sodiophilic sites.

Main Methods:

• Incorporation of Ag nanoparticles onto HNTs to create a sodiophilic scaffold.
• Density Functional Theory (DFT) calculations to investigate sodium binding energy and adsorption.
• Electrochemical testing of symmetric and full sodium metal batteries.

Main Results:

• Ag nanoparticles significantly increased sodium binding energy on HNTs/Ag compared to HNTs alone.
• HNTs facilitated faster Na+ transfer kinetics and selective anion adsorption, preventing space charge formation.
• Achieved high Coulombic efficiency (~99.6%), long lifespan (>3500 h), and remarkable cycle stability in sodium metal batteries.

Conclusions:

• The synergistic effect of HNTs and Ag nanoparticles provides an effective method for dendrite-free sodium metal anodes.
• This nanoclay-based sodiophilic scaffold design offers a novel strategy for enhancing battery safety and performance.