Multiple Na⁺ transport pathways and interfacial compatibility enable high-capacity, room-temperature quasi-solid...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-metal batteries (SMBs) offer high capacity for large-scale energy storage but suffer from safety issues like dendrite growth and side reactions, especially with liquid electrolytes.
• Developing safe, non-flammable electrolytes with high ionic conductivity and dendrite resistance is crucial for advancing SMB technology.

Purpose of the Study:

• To engineer novel quasi-solid polymer electrolytes (PPEs) for improved safety and performance in sodium-metal batteries.
• To investigate the role of polymerized polyethylene glycol diacrylate (PEGDA) modification in enhancing electrolyte properties.

Main Methods:

• Development of PEGDA-modified PVDF-HFP based quasi-solid polymer electrolytes (PPEs) incorporating sodium bis(trifluoromethanesulfonyl)imide and sodium bis(oxalato)borate salts.
• Characterization of PPEs for ionic conductivity, mechanical strength, and electrochemical stability.
• Testing of Na||Na symmetric cells and Na3V2(PO4)3|PPE-50|Na full cells to evaluate battery performance and cycling stability.

Main Results:

• The optimized PPE-50 exhibited high ionic conductivity (3.42 × 10⁻⁴ S cm⁻¹) and mechanical strength (14.0 MPa).
• Na||Na symmetric cells demonstrated high stability over 800 hours at 0.2 mA cm⁻², indicating suppressed dendrite growth.
• A Na3V2(PO4)3|PPE-50|Na battery delivered a discharge capacity of 101.5 mAh g⁻¹ at 1.0C after 650 cycles.

Conclusions:

• PEGDA modification enhances PVDF-HFP electrolyte amorphicity and provides Lewis basic sites, facilitating Na+ transport and improving battery performance.
• The developed quasi-solid polymer electrolytes offer a promising pathway for safe and high-performance room-temperature sodium-metal batteries.
• The study highlights the potential of tailored polymer electrolytes for next-generation energy storage systems.