Electrospun 1D cobalt pyrophosphate porous nanofibers: Redox-active electrode material for asymmetric supercapacitor

Abstract

The ability of a supercapacitor to store energy is closely tied to the amount of surface area available for electroactive reactions. Using 1D nanostructure material not only allows for larger specific surface area compared to that of other nanostructures, but also provides a direct path for the movement of electrons, acting like a “freeway” in the axial direction. Considering the benefits herein, we report the synthesis of Co2P2O7 nanofibers as an electrode material for supercapacitor application using a facile and industrially applicable electrospinning method followed by calcination. The resulting nanofibers have a continuous, uniform, and web-like structure with many small pores, which gives high specific surface area of 234.499 m2 g−1. This high surface area improves the interaction between the Co2P2O7 nanofibers electrode and 3 M KOH electrolyte, thereby enhancing the electrochemical properties of the material. The prepared Co2P2O7 nanofibers electrode has a high specific capacity of 270.7 C g−1 at a high current density 80 A g−1 and good stability of 84.7 % after 3000 continuous cycles. Furthermore, an asymmetric supercapacitor (ASC) device was fabricated using carbon nanofibers (CNF) as another electrode material. The energy density 27.8 Wh kg−1 and power density 1.89 kW kg−1 of ASC at a current density of 2 A g−1 suggests that Co2P2O7 nanofibers could be a viable option as an electrode material for supercapacitors.