Unique Core−Shell Structured Polyaniline Nanofibers Toward Ultrahigh−Rate Flexible All−Solid−State Supercapacitor

Promoting charge storage and fast charging capability simultaneously is a long-standing challenge for supercapacitors. A facile flowing seed polymerization is adopted to prepare polyaniline (PANI) nanofibers, in which phytic acid (PA) doped oligomers are first produced as the seeds for promoting the highly oriented growth of PANI nanofibers accompanying with the copolymerization of m-aminobenzene sulfonic acid (ASA) and aniline occurred on the surface of PANI nanofibers, as a result, unique core-shell structured PANI nanofibers are continuously fabricated. Benefitting from compact nanofiber structure, excellent dispersion, and self-doping effect, as-prepared PANI nanofibers exhibit a specific capacitance of 671.2 F g^-1 at 2 A g^-1 and ultrahigh rate capability of 93.1% from 2 to 100 A g^-1. Then assembled all-solid-state supercapacitor can deliver the highest energy density of 28.3 Wh kg^-1 at a power density of 320.2 W kg^-1 with remarkable rate capability (81.2% from 1 to 20 A g^-1), cycle stability (77.5% after 5000 cycles) as well as light weight and flexibility. It is highly desirable that the present green and scalable approach can be further applied to fabricate other unique core-shell structured PANI nanofibers with appealing potentials in energy storage devices.