Investigating the thermal, mechanical, and electrochemical properties of PVdF/PVP nanofibrous membranes for supercapacitor applications

Abstract

Polyvinylidene fluoride and polyvinylpyrrolidone polymers incorporated with carbon black nanoparticles (50 nm) were electrospun to fabricate nanofibrous membranes for supercapacitor separators. Different weight percentages (0, 0.25, 0.5, 1, 2, and 4 wt %) of carbon black nanoparticles were dispersed in N,N-dimethylacetamide and acetone prior to the electrospinning processes at various voltage, pump speed, and tip-to-collector distances. The morphology, thermal, mechanical, hydrophobic, and electrochemical characterization of nanofibrous membrane were analyzed using different techniques, such as scanning electron microscopy, differential scanning calorimetry, capacitance bridge, thermogravimetric analysis, dynamic mechanical analyzer, and water contact angle. Effects of annealing and UV irradiation exposures on the nanofibrous membranes were investigated in detail. Test results revealed that the physical properties of the nanocomposite separators were significantly enhanced as a function of carbon black inclusions in the polymeric structures, which may be useful for the applications of supercapacitor separators and other energy storage devices.

Recent Advances in Poly(vinylidene fluoride) and Its Copolymers for Lithium-Ion Battery Separators

“…In some cases, nanoparticles are added to the matrix as fillers to increase its mechanical stability or ionic conductivity. In composites separators, the most widely used fillers are oxide ceramics (ZrO 2 [ 12 , 13 ], Al 2 O 3 [ 14 , 15 ], SiO 2 [ 16 , 17 ]), carbonaceous fillers (graphene [ 18 ], carbon black [ 19 ], carbon nanofiber [ 20 ]), and ionic liquids [ 21 ], among others.…”

Sudden solvent evaporation in bubble electrospinning for fabrication of unsmooth nanofibers

“…Sudden solvent evaporation occurs when air pressure decreases greatly and suddenly. During the bubble electrospinning or bubbfil spinning [3][4][5][6][7][8], an air-flow is input into the spun solution with a high pressure, and a polymer bubble is formed on the surface. When the bubble is broken, a sudden pressure drop is happened, and solvent evaporation occurs which -------------- makes each debris lose solvents for a fast solidification.…”

“…Nanoscale porous fibers have much more applications than smooth nanofibers. In this paper we will study a multiple solvent system in the bubble electrospinning for fabrication of PS/PVP composite nanofibers, PS (polystyrene) is an amorphous polymer and has good stability [1], and it can be easily dissolved in dimethyl formamide (DMF) [2], and PVP (polyvinylpyrrolidone) is a newly developed material which is a compound of PVC (polyvinylchloride) and PP (polypropylene) [3,4], the former has excellent hydrophilic while the later has good flexibility [5].…”

Friction‐induced electroactive β polymorph of poly(vinylidene fluoride)

“…Corresponding DSC data of unworn PVDF and wear debris are shown in Figure , and the overview is illustrated in Table . The crystallization degree ( X c ) was calculated as following equation: X c = Δ H m / , where Δ H m is fusion enthalpy and corresponds to fusion enthalpy of neat PVDF 100% crystallized ( X c = 1), = 104.6 J/g . The crystallization half‐time ( t 1/2 ) was determined as follows: t 1/2 = ( T 0 − T 1/2 ) / ϕ, where T 0 is the onset crystallization temperature, T 1/2 is the temperature where the relative degree of crystallinity is 0.5, and ϕ is cooling rate .…”

“…According to Table , peak melting temperature ( T m ) of wear debris is slightly higher than that of unworn PVDF. Due to all‐trans planar zigzag conformation and denser packing, melting temperature of β polymorph is commonly higher than that of α polymorph . Hence, increasing F (β) leads to higher T m .…”