Enhanced Ionic Conductivity via Suppressed Crystallization and Strengthened Dynamics in Solid Polymer Blend Electrolytes
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초록
내용
Poly(ethylene oxide) (PEO)-based solid polymer electrolytes have high crystallinity, limiting their ionic conductivity due to slow chain motion in crystalline phases. To overcome this, we suppressed the crystallization of PEO by utilizing its low molecular weight and incorporating high molecular weight poly(vinylidene fluoride) as the blend matrix. This resulted in flexible, self-standing solid polymer blend electrolytes (SPBEs) with an ionic conductivity of 2.9 x 10-4 S/cm at room temperature. Temperature-dependent ionic conductivities revealed a strong correlation between ionic conductivity and segmental dynamics, following the Vogel-Tammann-Fulcher relation. Further analysis through broadband dielectric spectroscopy, including AC conductivity, electric modulus, and dielectric loss isotherms, indicated a strong coupling behavior between relaxation times and ionic conductivity. This experimental system serves as a model for designing high-performance SPBEs with good mechanical properties and superior ionic conductivities.