Sodiophilic Interface Induces a NaF-Rich Solid Electrolyte Interface for Stable Sodium-Metal Batteries under Harsh...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-metal batteries (SMBs) are promising for next-generation energy storage.
• Challenges include sodium dendrite growth and electrolyte side reactions, hindering cycle life.
• Uniform sodium plating/stripping is critical for SMB safety and longevity.

Purpose of the Study:

• To develop an effective interfacial layer for sodium metal anodes.
• To improve the uniformity of sodium deposition and stripping.
• To enhance the electrochemical stability of sodium-metal batteries.

Main Methods:

• Coating sodium metal with a silver (Ag) interfacial layer.
• Investigating the sodiophilicity and conductivity of the Ag layer.
• Analyzing the formation of the solid electrolyte interphase (SEI) using Ag's interaction with PF6-.
• Evaluating symmetric and full cell performance under various conditions.

Main Results:

• The Ag layer acts as nucleation sites, guiding uniform sodium deposition.
• Enhanced electric field and ion flux distribution due to Ag's conductivity.
• Formation of a NaF-rich SEI layer, suppressing side reactions.
• Symmetric cells show over 1000 h stability at 3 mA cm-2.
• Full cells retain 90% capacity after 800 cycles at 20 C, with good performance across temperatures.

Conclusions:

• The Ag interfacial layer effectively addresses key challenges in sodium-metal battery development.
• Uniform sodium deposition and a stabilized interface lead to superior cycling stability.
• This strategy offers a viable pathway for high-performance and durable sodium-metal batteries.