Effect of PMMA blend and ZnAl2O4 fillers on ionic conductivity and electrochemical performance of electrospun nanocomposite polymer blend fibrous electrolyte membranes for lithium batteries

Abstract

Electrospun pure and hybrid nanocomposite PMMA blend fibrous electrolyte membranes with various x wt% of ZnAl₂O₄, (x = 2, 4, 6 and 8) ceramic fillers were prepared by an electrospinning technique. All the prepared electrospun pure P(VdF-co-HFP), PMMA blend [90% P(VdF-co-HFP)/10% PMMA] and nanocomposite PMMA blend [90% P(VdF-co-HFP)/10% PMMA/x wt% ZnAl₂O₄, (x = 2, 4, 6 and 8)] fibrous membranes were characterized systematically using X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. The activated separator-cum-nanocomposite PMMA blend fibrous electrolyte membranes were obtained by soaking in an organic liquid electrolyte solution containing 1 M LiPF₆ in EC : DEC (1 : 1, v/v). The newly developed novel nanocomposite PMMA blend fibrous electrolyte [90% P(VdF-co-HFP)/10% PMMA/6 wt% ZnAl₂O₄/LiPF₆] membrane showed low crystallinity, high thermal stability, low average fiber diameter, high electrolyte uptake, high conductivity (4.135 × 10⁻³ S cm⁻¹) at room temperature and good potential stability above 4.5 V. The optimized best composition of nanocomposite PMMA blend fibrous electrolyte membranes with 6 wt% ZnAl₂O₄ filler content is used for the fabrication of a (Li/NCPBE/LiCoO₂) CR 2032 coin type lithium cell. The fabricated CR 2032 lithium coin cell containing the newly developed nanocomposite polymer blend electrolyte (NCPBE) membrane delivers an initial discharge capacity of 157 mA h g⁻¹ and also exhibits stable cycle performance at a current density of 0.1C rate at room temperature.