Electrospun Polyaniline Nanofiber Networks toward High-Performance Flexible Supercapacitors

Flexible supercapacitors with merits of lightweight, flexibility, and large power density are promising energy storage candidates for portable and wearable electronic devices. Flexibility of electrode materials is critical to their performance, which can be optimized by the screening of soft materials and an effective morphology control strategy. Here, polyaniline (polyacrylonitrile (PANI)) nanofiber networks through a simple electrospinning method are reported, with superior mechanical and electrochemical properties for flexible supercapacitors. The 1D structure of nanofiber networks not only provides robust mechanical properties but also facilitates charge transport during charge–discharge dynamics. The PANI nanofiber electrode shows a tensile modulus of 89.8 MPa and break elongation of 5.89%, which exceed those of its bulk counterpart. The PANI nanofiber-based supercapacitor exhibits a high specific capacitance of 134 F g−1 at a current density of 1 A g−1 and good rate capability under current densities ranging from 1 to 10 A g−1. It shows an excellent working stability with a capacitance retention of 85.6% even after 20 000 cycles. Moreover, the device delivers stable capacity under various flexible conditions, including bending, twisting, and elongation. It is noteworthy that the performance of the device changes negligibly after 500 bending cycles under a bending angle of 180°, displaying great potential for practical applications in flexible electronics.