Impedance analysis of PEG plasticized PEO-based composite polymer electrolytes for sodium-ion batteries

Solid-state sodium-ion batteries (SSIBs) will be the next generation batteries due to the high safety, low price, and availability of sodium resources. Composite polymer electrolytes (CPEs) are promising electrolytes because of easy fabrication, good stability, and high flexibility facilitating a good electrolyte-electrode interface, although their ionic conductivities are still unsatisfied. In this work, a CPE made of polyethylene oxide (PEO), Na 3 Zr 2 Si 2 PO 12 , and NaClO 4 has been fabricated. To further enhance the ionic conductivity and a good electrolyte–electrode interface, polyethylene glycol (PEG) is added as a plasticizer. The electrochemical impedance spectroscopy (EIS) demonstrates effect on conductivity by introducing PEG.