Low cost, catalyst free, high performance supercapacitors based on porous nano carbon derived from agriculture waste

The present work exhibits experimental results obtained from the analysis of porous nano carbon synthesized from agriculture waste for the evaluation of high-performance supercapacitors. The material has been prepared by pyrolysis at different temperatures. All the synthesized materials were characterized using EDS, FE-SEM, TEM, FTIR, XPS, and Raman spectroscopy. Porous nature was determined from N2 sorption experiments. The electrochemical studies were done in three and two electrode setups. The maximum specific capacitance obtained was 174 F/g at 0.1 A/g in 4.0 M KOH electrolyte. The symmetric supercapacitor exhibited a specific capacitance of 119.2 F/g at 0.1 A/g and a specific energy of 32.6 Wh/kg. The device exhibited impeccable stability for 25,000 charge-discharge cycles, with 97.8% coulombic efficiency. Capacitance retention of 93% was observed even at the end of 10000th cycles, suggesting the huge capacity of biomass-derived non-activated carbon nanomaterials for efficient, stable high-performance electrodes in electrochemical energy storage applications.