A Eutectic Aluminum-Tin Alloy Substrate for Anode-Free Na Battery.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium (Na) batteries are gaining attention due to abundant Na resources.
• Anode-free Na batteries offer high energy density but face challenges in cyclic stability.
• The anode substrate design is critical for stable sodium plating and stripping.

Purpose of the Study:

• To develop a cost-effective and efficient anode substrate for anode-free Na batteries.
• To investigate the role of aluminum-tin eutectic alloy in promoting uniform sodium nucleation.
• To enhance the cyclic stability and performance of anode-free Na batteries.

Main Methods:

• Fabrication of an aluminum-tin eutectic alloy substrate via a simple melting process.
• Electrochemical characterization of sodium plating/stripping behavior on the alloy substrate.
• Fabrication and testing of a full cell using the developed anode substrate and a Na3V2(PO4)3 cathode.

Main Results:

• The aluminum-tin alloy substrate effectively disrupts the passivation layer and promotes uniform sodium nucleation.
• Achieved highly reversible Na plating/stripping with an average coulombic efficiency of 99.97%.
• Demonstrated a cycle life exceeding 4000 cycles and 81% capacity retention in a full cell after 100 cycles.

Conclusions:

• The aluminum-tin eutectic alloy is a promising anode substrate for high-performance anode-free Na batteries.
• This approach offers an efficient strategy for improving the stability and longevity of next-generation sodium batteries.
• The developed substrate significantly outperforms traditional aluminum foils in anode-free Na battery applications.