Designing a Quasi-Liquid Alloy Interface for Solid Na-Ion Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state sodium-ion batteries (SSIBs) offer high energy density and safety.
• Key challenges include sodium dendrite growth and poor electrode-electrolyte wettability.

Purpose of the Study:

• To design a stable, dendrite-suppressed quasi-liquid alloy interface for SSIBs.
• To improve the electrochemical performance and safety of solid-state sodium-ion batteries.

Main Methods:

• Development of a carbon-encapsulated sodium-potassium alloy interface (C@Na-K).
• Electrochemical testing of symmetrical and full cells using the novel interface.

Main Results:

• The C@Na-K interface demonstrated improved wettability and accelerated charge transfer.
• Symmetrical cells achieved stable cycling over 3500 hours at 0.1 mA/cm² and a critical current density of 2.6 mA/cm² at 40 °C.
• Full cells exhibited 97.1% capacity retention and 99.6% average Coulombic efficiency after 300 cycles at 0.5 C.

Conclusions:

• The quasi-liquid alloy interface effectively suppresses sodium dendrites and enhances battery performance.
• This approach validates the use of liquid alloy interfaces for high-energy SSIBs.
• The findings provide a foundation for developing next-generation high-energy SSIBs.