Orderly and highly dense polyaniline nanorod arrays fenced on carbon nanofibers for all-solid-state flexible electrochemical energy storage

Conducting polymer nanoarray structures had attracted increasing attention as potential electrode materials in supercapacitor devices. In this article, the orderly and highly dense polyaniline (i.e., PANI) nanorod arrays had been successfully grown onto the surface of carbon nanofibers(i.e., CNFs) to form PANI@CNFs composite via a one step of facile chemical oxidation method. The specific capacity of the single PANI@CNFs composite electrode was 758 C/g and 720 C/g at current densities of 1.0 and 5.0 A/g, respectively, while the cycling stability could maintain 85% of the initial capacity after 1000 charge-discharge cycles. Furthermore, two pieces of PANI@CNFs composite electrodes were fabricated into a symmetric all-solid-state flexible supercapacitor device to drive small electronic equipments using polyvinyl alcohol-H2SO4 hydrogel as solid electrolyte, while the normal filter paper acted as a separator. The as-prepared symmetric supercapacitor device had excellent electrochemical performance with specific capacitance of 285 F/g at a current density of 0.5 A/g. The maximum energy density was 10.04 Wh/kg at a power density of 225 W/kg and showed no obvious decrease in the performance with a bending angle of 45° or 90°. The as-prepared symmetric all-solid-state flexible supercapacitor device had good promising applications in small wearable electronics.