A New Quasi-Solid Polymer Electrolyte for Next-Generation Na-O₂ Batteries: Unveiling the Potential of a...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Sodium-oxygen (Na-O2) batteries are promising for high energy density storage.
• Developing stable and efficient electrolytes is crucial for Na-O2 battery performance.
• Quasi-solid polymer electrolytes (QSPEs) offer potential advantages over liquid electrolytes.

Purpose of the Study:

• To investigate a novel quasi-solid polymer electrolyte (QSPE) based on polyamide (PA) and polyethylene oxide (PEO) for Na-O2 batteries.
• To evaluate the electrochemical properties and performance of the Pebax1657 QSPE.
• To compare the QSPE's performance against conventional liquid electrolytes.

Main Methods:

• Synthesis and characterization of the Pebax1657 QSPE with NaTFSI salt.
• Electrochemical testing including ionic conductivity, oxidation potential, and transference number measurements.
• Long-term galvanostatic cycling in Na|Na symmetrical cells and Na-O2 battery configurations.

Main Results:

• The Pebax1657 QSPE exhibited high ionic conductivity (6.57 × 10⁻⁴ S cm⁻¹) and an oxidation potential of 4.69 V.
• Structural analysis indicated reduced PEO crystallinity and ordered nanodomains, facilitating Na⁺ transport.
• Stable cycling in Na|Na cells for 210 h with low overpotentials (≈80 mV) was achieved, outperforming liquid electrolytes.
• Na-O2 cells demonstrated higher discharge capacities and improved cycle life (25-35 cycles) with 80-90% Coulombic efficiency.

Conclusions:

• The Pebax1657 QSPE demonstrates excellent electrochemical stability and ionic conductivity for Na-O2 batteries.
• It offers superior performance, including lower overpotentials and better capacity retention, compared to state-of-the-art electrolytes.
• The QSPE's sustainability and versatility make it a strong candidate for advanced energy storage applications.