Advanced Biocoal\nCarbon Materials from Biorefinery\nfor both Supercapacitors and Lithium-Ion Capacitor Applications

Advanced carbon materials are crucial for applications\nin supercapacitors\n(SCs) and Li-ion capacitors (LICs) to advance consumer electronics\nand e-vehicle applications. The current study introduces an innovative\napproach to transform biorefinery-derived biocoal into graphitized\nactivated carbon for SCs using ultrasonic-assisted Fe-based catalytic\ngraphitization and hard carbon for LICs using high-temperature carbonization\nmethods. Utilizing biocoal-derived activated carbon (BCA) and hard\ncarbon (BCHC) in various cell configurations demonstrates the potential\nof sustainable and cost-effective materials for advanced energy storage\ndevices. The supercapacitor electrode material (BCA) exhibits an impressive\nspecific capacitance of 153.33 F g<sup>–1</sup> and a low ESR\nvalue of 0.28 Ω. The constructed pouch cell supercapacitor device\nusing BCA retains 90% of its capacitance and powers a string of 20\nwarm white LEDs for up to 21 min. The LIC based on biocoal-derived\nhard carbon shows a maximum specific capacity of 118 mAh g<sup>–1</sup>, a Coulombic efficiency of 92.88%, and the capability to power LEDs.\nThese findings suggest practical implications for developing more\nefficient and sustainable energy storage devices with broad utility,\nleveraging industrial waste to create advanced electronic materials.