Assessment of influence of finely dispersed carbon nanotubes in polymer electrolytes for lithium batteries

Electrospun membranes of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)/multi-walled carbon nanotubes (MWCNTs) composite are prepared and loaded with lithium salts. Field emission electron microscopy provides evidence for the uniform distribution of MWCNTs into the polymer matrix. Interconnected morphology for the composite provides path for lithium ion conduction. Results from electrochemical impedance spectroscopy inform that the presence of MWCNTs in PVdF-HFP matrix improves interfacial stability between lithium electrode and membrane and augment conduction path. Equivalent circuits are generated based on impedance analysis to reveal the contribution of MWCNTs toward conductivity. A prototype cell is fabricated. The electrospun PVdF-HFP/MWCNT (2%) shows an ionic conductivity of about 5.85 mS/cm at 25°C and a high anodic stability.