Preparation And Performance Study On Electrospining Composite Electrodes Made Of PANI/CNT Suspension For Supercapacitors

Electrochemical supercapacitor has long been considered as an attractive energy-storage device because of its advantages such as high power density, fast charging/discharging rates, long cycle life and high reliability. It is widely used in the fields such as wind power generation, transportation facilities, wireless communication and electronic equipment The electrodes with high specific surface area and proper porosity have significant impacts on the supercapacitor performance. In this work, supercapacitor electrodes with PANI/CNT suspension were prepared using electrospinning techniques. The fiber electrodes with large specific surface area were obtained with different electrospinning parameters. Effects of electrospun microstructure on the electrodes performance were comparatively studied and discussed.The electrospinning platform, electrospinning parameters, test instrument and experimental process were introduced. Polyvinyl alcohol ?PVA?/sulfuric acid ?H2SO4? gel electrolyte was prepared, and PANI composite was also synthesized by in-situ polymerization, The physical properties of the PANI/MWCNT suspension were tested and the results showed that the suspension physical properties met the requirements of forming stable electrospinning taylor cone.The influences of electrospinning parameters including voltage, collector-needle distance ?CND? and the suspension flow rate ?SFR? in fiber diameter were explored. Results show that the voltage has little impact on the average diameters of the fibers. It is easy to form beaded structure when the voltage is too high or too low. The average diameters of the fibers decrease when increasing the collector-needle distance or decreasing the suspension flow rate. The surface area of PANI/MWCNT fiber membrane was characterized using nitrogen adsorption-desorption curve and results show that the specific surface area of the fiber membrane increases with smaller fiber diameter.Fiber membrane electrodes with average diameter of 2.89,2.28,1.70 and 1.21?m were prepared by changing the parameters of electrospinning, and the impact of fiber diameter on the supercapacitor performance was studied. The specific capacitance of the electrodes is 129.5, 140,159 and 180F·g^-1 and the specific surface area is 57,64,74 and 83 m2·g^-1, respectively, both of all increase when the average diameters of the fibers decrease. High specific surface area of the electrode provides more active sites in the faraday reaction process, and also increases the chances of the fibers in contact with the electrolyte ions, which improves the performance of electrochemical supercapacitor.Nano-fiber membrane electrode and micron fiber membrane electrode were prepared and the impact of the fiber diameter's order of magnitude on the supercapacitor performance was studied. The specific capacitance of the electrodes was 219 and 147 F·g?1 and the energy density was 30.4 and 20.4 Wh·kg^-1, respectively. The specific capacitance of the electrodes can retain 91% and 88% after 1500 charge/discharge cycles. Results show that, nano-fiber electrode significantly improves the specific capacitance and energy density of the supercapacitor.