A new biomass derived rod-like porous carbon from tea-waste as inexpensive and sustainable energy material for advanced supercapacitor application

The porous carbons derived from bio-mass precursors for energy storage devices have gained increased research attention due to their cost effectiveness, easiness in fabrication, eco-friendly nature and sustainability. In the present work, we have successfully prepared the highly porous carbon with tube-like structures from tea-waste raw material using facile and clean treatments of pre-carbonization, acid washing and KOH activation procedures. The contained inert inorganic impurities were completely removed by acid and KOH treatments, resulting in much increased carbon porosity. The prepared biomass porous carbon has a high pore volume with a large surface area of 1,610 m(2 )g(-1). The electrochemical properties of the prepared porous carbon were analyzed with a 3-electrode configuration in 6 M KOH electrolyte. It is displayed that the porous carbon exhibited the high specific capacitances of 332 F g(-1) at 1 A g(-1), and 222 F g(-1) at 100 A g(-1) when current density increased 100 times, representing an outstanding rate performance. Besides, the porous carbon has achieved an excellent long-cycling life with only 2.2% loss of its initial capacitance over 100,000 cycles even at 100 A g(-1). The observed desirable electrochemical behavior of the new biomass porous carbon derived from tea waste would be a competitive candidate as cathode material in the development of high-performance and green supercapacitors for advanced energy storage devices. (C) 2020 Elsevier Ltd. All rights reserved.