Preparation Of P(VDF-HFP) Composite Electrolyte By Electrospinning Technology

In this paper, PEO/P(VDF-HFP), P(VDF-HFP)/IL and P(VDF-HFP)/soggy sandcomposite electrolyte membranes were prepared by compositing and plasticizingmodification and Inorganic doping from the angle of electrostatic spinning solution.Poly (vinylidene fluoride hexafluoropropylene (P(VDF-HFP)) or P(VDF-HFP) andpolyethylene oxide (PEO) mixture were used for polymer matrix. The conductivityand mechanical properties of composite electrolyte membrane were improved, basedon PEO and salt complexion of ionic liquids and ionic liquid of P(VDF-HFP) similarto the effect of plasticizer, and wet sand electrolyte (soggy sand) works as inorganicadditives. The structure, absorptivity, thermodynamic performance, andelectrochemical properties were all chartered and studied.PEO and P(VDF-HFP) were both added into the solution at the same time firstlyand the composite membranes get higher conductivity and wide electrochemicalwindows which are higher than both the two pure membrane. The PEO has sharedelectrons of the ether oxygen and a strong affinity with the hydrogen bonds. What ismore, PEO can form complexes with a lot of organic low molecular compounds,polymer and some inorganic electrolytes. P(VDF-HFP) is binary copolymer of thepartial fluorine ethylene and hexafluoropropylene. The crystallization and meltingpoint of P(VDF-HFP) reduced with the addition of hexafluoropropylene, and theswelling of solvent and softness of products enhanced. The composite betweenelectrolyte film and composite electrode increased, and the interface resistance ofelectrode and the electrolyte membrane decreased. The above two reasons devote tothe increase of migration rate of Li+. The introduction of hexafluoropropylene alsodragged in a lot of CF3groups, which lead to the increase of free volume of molecular structure and the decrease of melting point. The interaction of the two kinds polymersreduced the crystallinity of the composite membranes, increased its elastic modulus,tensile strength and strain, at the same time, kept high conductivity and wideelectrochemical window.Ionic liquids and soggy sand electrolyte were also added into electrostaticspinning solution for the first time, the free volume of chain segment motion increase,and they play a role of plasticizer which is devoted to the improvement of theelectrochemical properties. The presence of inorganic filler changed the segmentarrangement structure of the polymer itself, reduced the crystallinity and glasstransition temperature, and thus enhanced the conductivity of gel polymer electrolyte.The complexion between inorganic fillers and polymer is conducive to theimprovement of conductivity. Inorganic nanoparticles can also lead to the increase ofsystem viscosity, to improve the interface stability of the polymer electrolyte andelectrode materials. The interaction of Lewis acid or dipole between polymer andinorganic additives devote to create high conductivity interface layers. It enhances themobility of carriers and the conductivity.