Interfacial-engineering-enabled practical low-temperature sodium metal battery.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state sodium batteries are explored as safer alternatives to liquid electrolyte systems.
• Key challenges include high interfacial resistance and sodium dendrite growth.
• Existing solid electrolytes face limitations in performance and stability.

Purpose of the Study:

• To develop a novel solid electrolyte for solid-state sodium batteries.
• To address interfacial resistance and dendrite formation issues.
• To enhance the overall performance and safety of sodium batteries.

Main Methods:

• Fabrication of yttria-stabilized zirconia (YSZ)-enhanced beta-alumina solid electrolyte (YSZ@BASE).
• Interface impedance measurements with sodium metal anode at 80°C.
• Critical current density evaluation.
• Fabrication and testing of a quasi-solid-state Na/YSZ@BASE/NaNi$_{0.45}$Cu$_{0.05}$Mn$_{0.4}$Ti$_{0.1}$O$_{2}$ full cell.
• Electrochemical characterization and theoretical calculations.

Main Results:

• YSZ@BASE exhibits extremely low interface impedance (3.6 Ω cm² with Na metal anode at 80°C).
• Achieved a high critical current density of ~7.0 mA cm⁻².
• Full cell demonstrated a capacity of 110 mAh g⁻¹ with >99.99% Coulombic efficiency.
• 73% capacity retention over 500 cycles at 4C and 80°C.
• Stable β-NaAlO₂-rich solid-electrolyte interphase and YSZ support suppressed Na dendrites.

Conclusions:

• The YSZ@BASE material effectively reduces interfacial resistance and suppresses sodium dendrite growth.
• The developed quasi-solid-state cell shows excellent electrochemical performance and cycling stability.
• This advancement offers a promising pathway for developing safe and high-performance solid-state sodium batteries.