Li Salt Assisted Highly Flexible Carbonaceous Ni₃N@polyimide Electrode for an Efficient Asymmetric Supercapacitor

This work used a highly flexible, sustainable polyimide tape as a substrate to deposit ductile-natured carbonaceous Ni₃N (C/Ni₃N@polyimide) material for supercapacitor application. C/Ni₃N was prepared using a co-sputtering technique, and this method also provided better adhesion of the electrode material over the substrate, which is helpful in improving bending performance. The ductile behavior of the sputter-grown electrode and the high flexibility of the polyimide tape provide ultimate flexibility to the C/Ni₃N@polyimide-based supercapacitor. To achieve optimum electrochemical performance, a series of electrochemical tests were done in the presence of various electrolytes. Further, a flexible asymmetric supercapacitor (NC-FSC) (C/Ni₃N//carbon@polyimide) was assembled by using C/Ni₃N as a cathode and a carbon thin film as an anode, separated by a GF/C-glass microfiber soaked in optimized 1 M Li₂SO₄ aqueous electrolyte. The NC-FSC offers a capacitance of 324 mF cm^-2 with a high areal energy density of 115.26 μWh cm^-2 and a power density of 811 μW cm^-2, with ideal bending performance.