(255c) Hybrid-Capacitors with Polyaniline/Carbon Electrodes Fabricated Via Simultaneous Electrospinning/Electrospraying

Hybrid-capacitors have the potential to synergistically combine the benefits of both electrochemical double layer capacitors (EDLCs) (longer cycle life) and pseudo-capacitors (higher capacitance). However, new processes that intimately combine the two primary materials from each capacitor (carbon and conductive polymer, respectively) within the electrodes in an ordered fashion on the nanoscale are needed to realize this potential. In this study, we report on a novel method (simultaneous electrospinning/electrospraying (E/E)) for fabricating hybrid-capacitors with high surface area electrodes consisting of polyaniline (PANI) and carbon particles (referred to as E/E electrodes). E/E produces a PANI/carbon nanofiber network with fiber diameters in the range of 500 to 2000 nm. The hybrid-capacitor with E/E electrodes exhibits an excellent specific capacitance of 235 F g^-1 (vs. 138 F g^-1 for capacitor with state-of-the art hybrid electrodes) at a current density of 1 A g^-1. Moreover, the capacitor with E/E electrodes retains approximately 84 % capacitance after 1000 charge-discharge cycles (vs. 67 % for capacitor with state-of-the art hybrid electrodes). A post mortem electron microscopy study of the E/E electrodes provides a rationale for the improved cycling stability. These results demonstrate the feasibility of producing E/E electrodes and their promise as future materials in hybrid-capacitors.