Macroporous nanocomposite polymer electrolyte for lithium-ion batteries

A novel macroporous nanocomposite polymer membrane (NCPM) based on poly(vinylidene difluoride-co-hexafluoropropylene) [P(VDF-HFP)] copolymer was prepared by in situ hydrolysis of Ti(OC₄H₉)₄ using a non-solvent-induced phase separation technique. SEM micrograph shows that the yielding TiO₂ nanoparticles are dispersed uniformly in the polymer matrix and there are a lot of spherical macropores connecting with each other by some smaller pores. DSC results exhibit that the crystallinity of polymer matrix decreases with the incorporation of TiO₂ nanoparticles. The tensile stress of the NCPM is 9.69 MPa and its fracture strain 74.4%. After immersion in 1.0 mol l^-1 LiPF₆/ethyl carbonate (EC)-dimethyl carbonate (DMC), the ionic conductivity of the obtained nanocomposite polymer electrolyte (NCPE) is 0.98 × 10^-3 S cm^-1 at 20 °C. Lithium-ion batteries, which use this kind of NCPE as the separator and electrolyte, display good discharging performance at different current densities, presenting promise for its practical application.