Catalyst free approach for the fabrication of CoN//Zn3N2 asymmetric configuration for highly efficient flexible supercapacitor

This report presents a single-step deposition of crystalline and catalyst-free cobalt nitride (CoN) and zinc nitride (Zn3N2) electrodes on a flexible current collector for highly efficient flexible supercapacitors. These proposed electrodes take full advantage of mechanical strength, electrochemical stability, and tremendous electrical conductivity with excellent adhesion to a flexible current collector and show high capacitive performance with outstanding cyclic life. The asymmetric supercapacitor (ASC) was constructed using CoN as a negative electrode and Zn3N2 as a positive electrode, assembled with 1 M Na2SO4 aqueous electrolyte soaked Whatman filter paper as the separator. This ASC exhibits a wider voltage window (up to 2 V), good capacitance (75.4 Fg−1), and high specific energy (42 Wh kg−1) with good capacitance retention (93.6% for the flat cell and 80.1% for the 80° bend cell) over 5000 charging discharging cycles. Therefore, this design of ASC potentially expands the performance of high frequency and flexible electronics.