Hierarchically structured Cu2P2O7 nanoflakes as a binder-free electrodes for high-performance supercapacitors

Abstract

Metal phosphates-derived materials are emerging as promising candidates for electrode materials in energy storage systems due to their excellent redox properties and high electrical conductivity. In this work, we present a novel study and first report on the fabrication of binder-free electrodes using ultrathin Cu2P2O7 nanoflakes, facilitated through a cost-effective and industrially scalable chemical bath deposition (CBD) technique. These electrodes exhibit a unique surface architecture resembling micro-spherical flower structures, which are directly grown on flexible and conductive nickel foam (NF) substrates. The nanoscale structure of the Cu2P2O7 electrodes is meticulously designed to provide high porosity and an impressive specific surface area, allowing for efficient electrolyte ion infiltration. Consequently, these electrodes exhibit an exceptional specific/areal capacitance value of 1187 F g−1, 1894 mF cm−2 at a scan rate of 5 mA cm−2 and a specific capacity value of 644 C g−1. Notably, when integrated into an aqueous asymmetric supercapacitor (AASC) device, the Cu2P2O7-derived micro-sized flower structure delivers a significant energy density of 39.46 Wh kg−1, a notable specific power of 1.08 kW kg−1, and maintains an exceptional 99 % retention even after 10,000 charge/discharge cycles. This research highlights the potential of transition metal phosphates (TMPOs), specifically Cu2P2O7, as superior electrode materials for supercapacitor applications, offering a scalable and cost-effective approach for enhancing energy storage performance.