A Fast Na-Ion Conduction Polymer Electrolyte via Triangular Synergy Strategy for Quasi-Solid-State Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Polymer electrolytes offer high safety and processability for quasi-solid-state batteries.
• Sluggish ion transfer at room temperature hinders their widespread application.

Purpose of the Study:

• To accelerate sodium-ion (Na+) conduction in polymer electrolytes.
• To develop high-performance and safe quasi-solid-state batteries.

Main Methods:

• A triangular synergy strategy combining polymer-salt (PVDF-HFP/NaTFSI), ionic liquid (EmimFSI), and an electron-rich additive (Nerolin).
• Physicochemical characterizations and theoretical calculations to analyze ion transport mechanisms.
• Fabrication and testing of quasi-solid-state battery cells.

Main Results:

• The strategy significantly enhanced Na+ conduction by weakening polymer chain interactions and creating additional ion pathways.
• Electron-rich Nerolin facilitated NaTFSI dissociation and restrained cation migration, lowering the energy barrier for ion transport.
• Achieved high ionic conductivity (1.37×10⁻³ S cm⁻¹) and sodium-ion transference number (tNa+ = 0.79) at 25°C.
• Demonstrated reliable rate capability and stability (200 cycles, 99.2% capacity retention at 0.5 C) with enhanced safety.

Conclusions:

• The proposed triangular synergy strategy effectively accelerates ion transport in polymer electrolytes.
• This approach leads to high-performance, safe quasi-solid-state batteries with improved ionic conductivity and stability.