Construction of self-supporting PDOL electrolyte membranes for stable solid-state lithium metal batteries

Poly(1,3-dioxolane) (PDOL) solid-state electrolytes (SSEs) have garnered significant attention due to their exceptional interfacial properties and high compatibility with existing battery manufacturing processes. Current research on PDOL-based SSEs primarily focuses on composite structures with supporting frameworks, as standalone 1,3-dioxolane (DOL) cannot effectively isolate the cathode and anode. However, the electrode materials and separators in batteries may inhibit DOL polymerization, resulting in monomer accumulation. This residual monomer not only complicates the assessment of electrolyte performance but also accelerates battery degradation. In this study, we report the first realization of a self-supporting PDOL solid-state electrolyte membrane (PDOL-SE), fabricated via a pre-polymerization process followed by roller pressing, marking the first PDOL-based SSEs independent of supporting frameworks. Electrochemical characterization revealed that PDOL-SE exhibits an ionic conductivity of 0.122 mS cm^-1 at 30 °C and an exceptionally high lithium-ion transference number of 0.93. When tested in LiFePO₄|PDOL-SE|Li pouch cells, the system delivered a discharge-specific capacity of 143.9 mAh g^-1 with a high-capacity retention of 91 % after 150 cycles. The straightforward roller pressing molding technique provides a novel methodology and perspective for investigating the intrinsic electrochemical properties of PDOL-based SSEs.