Hierarchical porous carbon derived from petroleum coke via one-step chemical activation for the fabrication of a supercapacitor and real time clock application

Abstract

The escalating demand for energy requires highly efficient energy storage devices and advanced materials. Low-cost carbon resources and their derivatives have always been a topical research area. Petroleum coke is an abundant and affordable resource that contributes to the scalability and cost effectiveness of carbon materials. Porous carbon derivatives have acquired great attention for energy storage and conversion owing to their large surface area, environmental friendliness, exceptional electrical conductivity, and economic viability. Thus, in this work, we directly synthesized hierarchical porous carbon materials from oil refinery petroleum coke (pet-coke) using a single-step KOH activation method to utilize them for the fabrication of a coin cell supercapacitor for electronic application. The synthesized pet-coke based porous carbon shows a high specific surface area (1108 m² g⁻¹) and excellent porosity. After conducting extensive electrochemical analysis, it shows promising specific capacitances of 170 and 70 F g⁻¹ in aqueous and organic electrolytes, respectively. Further, a coin cell supercapacitor was fabricated using the pet-coke derived porous carbon in an organic electrolyte with a potential window of 2.7 V, demonstrating superior rate capability and durability. The calculated energy and power density of the fabricated coin cell indicate its favorable supercapacitor application to act as a backup power source for real time clock (RTC) application in electronics.