Salt-Assisted Recovery of Sodium Metal Anodes for High-Rate Capability Sodium Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable sodium metal batteries offer high energy density and cost-effectiveness.
• Sodium metal anodes are highly reactive, leading to inactive species formation and limiting battery performance.
• A stable solid-electrolyte interphase (SEI) is crucial for efficient sodium metal anode operation.

Purpose of the Study:

• To develop a strategy for recovering sodium (Na) activity in sodium metal anodes.
• To reinforce the solid-electrolyte interphase (SEI) for improved battery stability and longevity.
• To engineer the surface of sodium metal anodes for high power density applications.

Main Methods:

• An alkali, salt-assisted, assembly-polymerization strategy was employed.
• 3-glycidoxypropyltrimethoxysilane (GPTMS) was used as an alkali-reactive coupling agent.
• GPTMS forms a self-assembled layer converting inactive Na species into Si-O-Na coordination.

Main Results:

• Full recovery of electrochemical activity in sodium metal anodes was achieved.
• A robust GPTMS-derived SEI layer was formed, enhancing anode stability.
• High capacity (93.1 mAh g^-1) and long-term cycling (94.8% after 3000 cycles) were demonstrated at an ultrahigh rate of 30 C.

Conclusions:

• The developed strategy effectively recovers sodium metal anode activity and reinforces the SEI layer.
• This surface engineering approach offers a pathway for designing high power density and cost-effective alkaline metal batteries.
• The findings provide valuable insights for advancing sodium-based energy storage technologies.