Preparation and Characterization of Electrospun Gelatin Nanofibers for Use as Nonaqueous Electrolyte in Electric Double-Layer Capacitor

Abstract

A novel nanofibrous gel electrolyte was prepared via gelatin electrospinning for use as a nonaqueous electrolyte in electric double-layer capacitors (EDLCs). An electrospinning technique with a 25 wt% gelatin solution was applied to produce gelatin electrospun (GES) nanofiber electrolytes. Structural analysis of the GES products showed a clearly nanofibrous structure with fiber diameters in the 306.2–428.4 nm range and exhibiting high thermal stability, high tensile strength, and a stable form of nanofibrous structure after immersion in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4). After testing over a range of spinning times, GES electrolytes that were produced at 25 min (GES-25) had a suitable thickness for the assembly of EDLC with the optimized tensile properties and were used to fabricate EDLC test cells with EMImBF4. These test cells were compared to those with pure EMImBF4 and a separator as an electrolyte. The electrochemical properties of the test cells were characterized by charge-discharge testing, discharge capacitance, and alternative current (AC) impedance measurements. AC impedance measurements showed that the test cell with the GES-25/EMImBF4 gel electrolyte showed slightly poorer contact with the electrode when compared to that with pure EMImBF4, whereas exhibited comparable IR drop and discharge capacitance (calculated capacitance retention was 56.6%). The results demonstrated that this novel gel electrolyte can be used as a nonaqueous electrolyte in order to improve the safety in EDLCs.

Preparations and Properties of Ionic Liquid-Assisted Electrospun Biodegradable Polymer Fibers

“…Besides this, the mixture of solvents, for example, acetone/dimethylacetamide and chloroform/methanol have been employed for dissolving a cellulose derivative such as cellulose acetate [24][25][26]. On the other hand, PVA, starch, and gelatin can be dissolved in a polar solvent, such as water [33,34].…”

“…The symbol '⇑' corresponds to an increase in the properties, and '⇓' corresponds to a decrease in the properties, while '⇕' and '-' describe unchanged and not available, respectively. [39]; and (c) electrospun gelatin fibers [33] assisted by different ionic liquids as additives. Figure 7.…”

“…Figure 7. SEM micrographs of (a) electrospun cellulose acetate fibers [25]; (b) electrospun PLA fibers [39]; and (c) electrospun gelatin fibers [33] assisted by different ionic liquids as additives. [25]; (b) electrospun PLA fibers [39]; and (c) electrospun gelatin fibers [33] assisted by different ionic liquids as additives.…”

“…This is because cellulose is one of the most abundant biodegradable polymers on the earth. [12,30] Petroleum-based Collagen [19] Polybutylene succinate PBS [31] Ethyl cellulose [32] Polycaprolactone PCL [4] Gelatin [33] Polyvinyl alcohol PVA [34,35] Heparin [13] Silk [19,36,37] Natural waste Starch [34] Polylactic acid PLA [3,29,38,39] Recently, chitin, the second most abundant natural polymer after cellulose [1,29] has also been employed for the preparation of electrospun fibers. In addition, cellulose and chitin derivatives, such as cellulose acetate [24][25][26] and chitosan [12,30] were employed to prepare electrospun fibers.…”

Electrospinning process parameters optimization for biofunctional curcumin/gelatin nanofibers

“…Gelatin nanofibers (like collagen) have been used in biomedical applications such as cosmetics, wound dressing, tissue engineering, surgical treatments, etc [34]. Gelatin nanofibers (having sufficient mechanical properties to be used in these applications as nanofibrous mats) have been electrospun for ultrathin nanofibers [34][35][36][37][38][39][40][41][42][43][44]. These authors also reported that the properties of these nanofibers can be tailored as per requirements by optimizing input parameters such as voltage, viscosity, distance between the spinneret and rotating drum collector, and flow rate.…”