Large-Area and 3D Polyaniline Nanoweb Film for Flexible Supercapacitors with High Rate Capability and Long Cycle Life

Flexible, thin, and lightweight supercapacitors have been regarded as important power sources for portable and wearable electronics; however, these are usually limited by relatively low areal or volumetric performances compared to their gravimetric performance. In this paper, a large-area, thin, and flexible three-dimensional (3D) polyaniline nanoweb film with controlled nanomorphology is reported for the improvement of the areal and volumetric performances of supercapacitors. The 3D nanoweb structure provides large ion accessible active sites, short ion diffusion distance, and enhanced mechanical tolerance during electrochemical reactions. The resulting polyaniline nanoweb film electrodes exhibit a high areal capacitance of 303 mF/cm2 at 10 mV/s, a high capacitance retention of 73% even at a high scan rate of 1000 mV/s, and long-term cycle stability (98.9% capacitance retention over 10000 cycles). The all-solid-state flexible supercapacitors deliver high device area-specific and volume-specific energy densities of 12.7 μWh/cm2 and 1.0 Wh/L, respectively.