Tea waste biochar composite with nickel phthalocyanine as a potential supercapacitor electrode material

Biochars are well recognized to be prospective materials for renewable and sustainable energy demands around the world in recent times. The present study developed a good methodology for the preparation of nickel phthalocyanine/TW carbon composite (Ni-Pc/TWC) from used tea waste powders and nickel phthalocyanine through a simple carbonization and activation method. The structure of the synthesized materials were confirmed by various characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) with pore size distribution, UV–Vis, and Raman spectroscopy techniques. The electrochemical behaviors of the synthesized materials were analyzed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The Ni-Pc/TWC electrode material exhibited excellent specific capacitance value of 432 Fg −1 at 1 Ag −1 in an electrolyte, when compared to the individual materials TW carbon and nickel phthalocyanine. The Ni-Pc/TWC composite material showed good cyclic stability until 5000 cycles of charge–discharge study at 5 Ag −1 . This study provides an excellent and cost-effective approach for the used tea waste powder to achieve high performance biochar carbon materials for clean energy storage applications. Graphical abstract