Preparation and characterization of gel polymer electrolyte based on electrospun polyhedral oligomeric silsesquioxane-poly(methyl methacrylate)8/polyvinylidene fluoride hybrid nanofiber membranes for lithium-ion batteries

Abstract

As a kind of organic–inorganic hybrid materials with nanocage structure, polyhedral oligomeric silsesquioxane (POSS) has the advantages of good interaction with polymer and excellent thermal and mechanical stability. Star-shaped polyhedral POSS-poly(methyl methacrylate) (POSS-(PMMA n )8) with different molecular weights had been synthesized by sequential atom transfer radical polymerization (ATRP) with POSS-(C3H6Cl)8 as the initiator. Electrospun polyvinylidene fluoride (PVDF) composite gel polymer electrolytes (GPEs) modified by POSS-(PMMA n )8 were prepared, and their electrochemical and mechanical properties were assessed. The POSS-(PMMA n )8 particles were found to improve thermal stability and mechanical strength of the GPEs without decreasing electrochemical properties. Among all composite GPEs studied, the best comprehensive performance was obtained from PVDF-[POSS-(PMMA46)8] GPE: the porosity was 60.0%, and the tensile strength and the elongation at break were 4.94 MPa and 52.2%, respectively. Besides, the ionic conductivity was 4.85 × 10−3S cm−1 at room temperature, the electrochemical window could reach 6.0 V, and the interfacial impedance with Li electrode was 256.15 Ω. The cells with POSS-(PMMA)8-modified composite electrolytes also have good cycle performance. These results suggest that the PVDF-[POSS-(PMMA)8] composite GPEs are suitable for lithium-ion battery applications.