Entropy-Driven Polymer Electrolyte with Liquid Single-Atoms for Fast-Charging Solid-State Sodium Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Fast-charging in solid polymer electrolytes (SPEs) is limited by sodium ion (Na+) transport rates at interfaces and within the bulk.
• SPEs offer high interfacial compatibility, reducing interfacial impedance for ionic conduction.
• A key challenge is developing SPEs that simultaneously enhance bulk ionic conductivity and mechanical strength.

Purpose of the Study:

• To introduce an entropy-driven strategy using dynamic liquid single atoms to overcome limitations in SPEs for fast-charging.
• To develop a novel SPE material that enhances both ionic transport and mechanical properties.
• To investigate the in situ stress-voltage relationship during operation.

Main Methods:

• An entropy-driven strategy utilizing dynamic liquid single atoms to rearrange polymer chains.
• Acceleration of polymer complexation and dissociation to facilitate ion transport.
• Dynamic stress regulation by liquid atoms to improve mechanical strength.
• In situ monitoring of the stress-voltage relationship using a specialized electrolytic cell.

Main Results:

• The novel SPE demonstrated a capacity of 85.6 mAh g⁻¹ at 10 C with 91.76% capacity retention after 1000 cycles at 10 C.
• Enabled 5-minute fast-charging capability with a 19.8 µm thick electrolyte.
• Engineering application cells (Ah-level) showed 93.69% retention after 600 cycles at 1 C.

Conclusions:

• Dynamic liquid single atoms provide a new strategy for developing advanced SPEs.
• This approach effectively enhances ionic conductivity and mechanical stability for fast-charging applications.
• The developed SPEs show significant promise for high-performance energy storage devices.