Effect of thermal treatment on electrochemical performance of diesel particle-based electrodes for supercapacitors

Abstract

This study investigates the potential of diesel particles (DPs) emitted from marine diesel engine combustion as electrode materials for supercapacitors. The collected DPs were chemically purified and thermally treated at different temperatures to prepare carbon-based electrodes. The molecular structure, functional group characteristics, and degree of graphitization of the DPs treated at different temperatures were characterized using multiple analytical techniques. Their electrochemical performance was further evaluated through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements. The results show that DPs thermally treated at 600 °C exhibit significantly better electrochemical performance than untreated DPs. The single-electrode specific capacitance increased from 2.26 F/g to 88.23 F/g, representing an increase of nearly 40 times. This performance enhancement is due to the introduction of abundant structural defects on the electrode surface via chemical purification and high-temperature treatment, which increases the number of electrochemically active sites, along with an increased content of COOH functional groups that provide additional pseudocapacitance in alkaline electrolytes, thereby improving the overall electrochemical performance. This work can help with the resource utilization of DPs and promotes environmental protection, and provides new insights into the development of high-performance electrode materials for supercapacitors.