Facile, two-step synthesis of activated carbon soot from used soybean oil and waste engine oil for supercapacitor electrodes

Abstract

The present work deals with development of efficient, cost-effective supercapacitors capable of delivering electrical energy at high rates. This study depicts the green synthesis of porous carbon material using carbon soot (CS) collected from flames of oil-wick lamp, a method which is popularly used to make kajal in Indian demography. The activated carbon soot (ACS) was derived by burning used refined soybean oil and waste engine oil followed by chemical and thermal activation. The highest specific capacitance of the ACS-based EDLC supercapacitors was 44.8 and 61.4 Fg−1 at 0.5 mA cm−2 for soybean-based supercapacitor and engine oil-based supercapacitor, respectively, which shows the potential use of waste oils for electrochemical electrodes. Although the present study is focused on supercapacitor application, this work has broad environmental scope because it targets the efficient use of waste oils.