Mussel Stimulated Modification of Flexible Janus Pan/Pvdf-Hfp Nanofiber Hybrid Membrane for Advanced Lithium-Ion Batteries Separator

Abstract

Bicomponent polyacrylonitrile/Poly(vinylidene fluoride-co-hexafluoropropylene) (PAN/PVDF-HFP) Janus nanofibers based hybrid membrane was proposed by parallel electrospinning technology. Subsequently, modified PAN/PVDF-HFP hybrid membrane (M-PAN/PVDF-HFP) was further fabricated via mimicking the adhesive of mussel by coating dopamine alternative through polymerization of catechol and tetraethylenepentamine (TEPA) in weakly alkali solution. M-PAN/PVDF-HFP maintains the pore structure of the electrospun hybrid membrane and further provides excellent electrolyte infiltration, exhibiting high porosity (82.09%) and electrolyte retention (553.23%). Simultaneously, the mechanical strength of the separator was significantly improved (14.36 MPa). Electrochemical studies displayed that the M-PAN/PVDF-HFP composite membrane delivered superior ion conductivity (2.81 mS/cm) and wide electrochemical stability window (~5.25 V). The cell assembled by M-PAN/PVDF-HFP separator showed outstanding rate capability with high specific capacity of 147 mA h/g at 1 C and excellent cycle stability with discharge capacity of 120 mA h/g at 1 C after 600 cycles. Furthermore, M-PAN/PVDF-HFP separator exhibited ultra-flexibility with remarkable electrochemical performance after repeated buckling for 500 to 1000 time. This work provides new insights into polyamine modified hybrid membranes for the potential practical applications in lithium-ion batteries separator.

Keywords: M-PAN/PVDF-HFP, Janus nanofibers, Electrospinning, Flexible, Separator