Novel pseudocapacitive one-dimensional copper pyrophosphate (Cu2P2O7) nanofibers for asymmetric supercapacitor

Abstract

The redox activity of a supercapacitor electrode can be significantly compromised by irregular, non-uniform, and agglomerated morphologies of the material. The preparation of a one-dimensional fibrous morphology not only ensures a consistent, continuous, and well-separated network of fibers but also results in an increased surface area compared to higher-dimensional structures. In this study, the fabrication of a continuous network of one-dimensional copper pyrophosphate (Cu2P2O7) nanofibers through a straightforward polymer-based electrospinning method followed by calcination at 900°C is reported. The resulting Cu2P2O7 monoclinic nanofibers exhibited an average diameter of 95 nm, highlighting the enhanced surface area of the material. By employing nickel foam (NF) as a current collector, the Cu2P2O7/NF electrode demonstrated a remarkable specific capacitance of 567.31 F g-1 (357.4 C g-1) at 2 A g-1 in 1 M LiOH electrolyte, surpassing performances in 1 M KOH and 1 M NaOH electrolytes. Furthermore, we designed an asymmetric supercapacitor (ASC) device configuration by incorporating carbon nanofibers (CNFs) as the negative electrode. Cu2P2O7//CNFs asymmetric supercapacitor showcases an exceptional specific capacitance, reaching 143.73 F g-1 (244.34 C g-1) at a current density of 0.4 A g-1. This remarkable performance is complemented by a notable energy density of 57.69 Wh kg-1 and power density of 1104.7 W kg-1. Furthermore, even at an elevated power density of 5132.25 W kg-1, the device maintained a considerable energy density of 22.81 Wh kg-1. These findings underscore the viability of Cu2P2O7 nanofibers as a compelling choice for energy storage devices.