Fabrication and Characterization of PEO-Based Composite Solid Electrolytes Infiltrated into 3D- Nanoporous Membrane

Abstract

All-Solid-State Batteries (ASSBs) are drawing significant attention as next-generation energy storage devices due to their enhanced safety and high energy density. Among various solid electrolytes, poly(ethylene oxide) PEO is widely studied for its excellent film-forming capability and strong affinity for lithium salts. However, the practical application of PEO-based solid polymer electrolytes (SPEs) is hindered by low ionic conductivity at room temperature and poor electrochemical stability at high voltages. In this study, we fabricated a PEO-based Composite Solid Electrolyte (CSPE) by successfully infiltrating a PEO-lithium salt complex into a 3D-nanoporous membrane (NHF scaffold) to overcome these limitations. The resulting PLNHF composite electrolyte was systematically characterized and compared with the pristine PL electrolyte. Differential Scanning Calorimetry (DSC) analysis confirmed that the PLNHF sample exhibited a lower glass transition temperature (Tg) and a more amorphous structure compared to the PL sample, which facilitates the segmental motion of the PEO chains crucial for ion transport. Electrochemical Impedance Spectroscopy (EIS) revealed that the 3D-nanoporous structure significantly reduced the bulk resistance, thereby enhancing the room-temperature ionic conductivity of PLNHF compared to PL. Furthermore, Linear Sweep Voltammetry (LSV) demonstrated that the PLNHF composite electrolyte possesses a wider electrochemical stability window with superior resistance to oxidation at high potentials (>4.0V). These results confirm that the strategy of infiltration into a 3D-nanoporous membrane is highly effective for simultaneously improving both the ionic conductivity and the oxidative stability of PEO-based solid electrolytes. The developed PLNHF composite solid electrolyte is a promising candidate for realizing high-performance ASSBs compatible with high-voltage cathode materials. MS/MS 20241071