Hierarchical porous carbon derived from tea waste for energy storage applications: Waste to worth

It is still a difficulty to develop supercapacitor electrodes at a reasonable cost. The present work reports on the preparation of hierarchical porous carbon from tea wastes for supercapacitors application. Herein, the study finds a fruitful route for tea waste management wherein conversion of waste to worth resources is adopted. Waste tea leaves served as a raw material for the preparation of hierarchical porous carbons by two stage, process (precarbonization and chemical activation) aiming to produce a high performance supercapacitors electrode material. The samples were chemically activated using KOH in the temperature range, 600 °C to 900 °C after precarbonization. The BET surface area of the carbon samples were between 16 m2 g−1 to 1029 m2 g−1. The pore drilling and pore winding effect led to considerable development of well-defined micro-meso porosity. In particular, the hierarchical porous carbon prepared at 800 °C (WTC8) exhibited a superior performance for supercapacitor with highest capacitance of 490 F/g and over 99.7% capacitance retentivity even after 1000 cycles at 8 A/g. The outstanding electrochemical performance shows that hierarchical porous carbon electrodes derived from used tea solid waste behaves as a promising candidate for high performance supercapacitors and also proposes the proof of concept of waste to worth.