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.

Recently, we reported on autocatalytic electroless metallization of silicon using gold nanoparticles. This technology is expected to be a useful, low-cost, and reliable method to form electrodes on silicon for several devices, such as solar cells and power devices. For the fabrication of electrodes, it is important that the resistance, consisting of the sheet resistance of the metal patterns and the contact resistance between the metal and silicon, is low. In this study, we measure the contact resistance of metal electrodes on silicon prepared by autocatalytic electroless metallization using gold nanoparticles. The transfer length method is suitable to evaluate the contact resistance between electrolessly plated nickelphosphorus alloy thin films and silicon. The values obtained for the contact resistivity decrease as the film thickness increases from 0.5 to 2.3 µm. This decrease is caused by the decrease of the sheet resistance of the metal films. Reliable values for the contact resistivity were determined to be 0.9 and 1.2 mΩ cm 2 for p + -and n + -doped wafers, respectively. The contact resistivity depends on the gold nanoparticle coverage.