Coal-Derived Porous Carbon as Versatile Electrode Materials for Aqueous, Water-in-Salt, and Organic Electrolytes, and Fabrication of Pouch Cell Supercapacitor toward Power Application

This study focuses on the comprehensive analysis of porous carbon derived from coal feedstock for advanced applications in fabricating pouch cell supercapacitor prototypes. A simple chemical activation technique was employed to produce high-performance porous carbon, followed by assembly of the pouch cell supercapacitor prototype for power applications. The performance of the prototype was thoroughly analyzed by using electrochemical characterization techniques, including cycling stability assessment. The coal-based porous carbon exhibited high surface area (1480 m 2 /g), high porosity (0.66 cm 3 /g), and excellent electrochemical properties. Maximum specific capacitance values obtained for coal-derived porous carbon in aqueous, water-in-salt electrolyte (WIS), and organic electrolytes were 190, 127, and 93 F/g, respectively, revealing the excellent versatility of the material. Additionally, the supercapacitor demonstrated maximum power and energy density of 13.7 kW/kg and 23.3 Wh/kg, respectively, in the organic electrolyte. Two fabricated coal-based pouch cell supercapacitors (100F/2.7V) were also compared with a commercial supercapacitor. The coal-based pouch cell exhibited gravimetric specific energy and usable specific power of 4.5 Wh/kg and 736 W/kg, respectively, with a cycling stability of approximately 90% after 10,000 cycles. These coal-based pouch cell supercapacitors were successfully demonstrated for use in lighting a string of LEDs (4.5 V). Overall, the research findings highlight the potential of coal-derived porous carbon as an efficient electrode material for supercapacitor applications, offering a promising pathway for utilizing abundant coal resources in sustainable energy storage applications.