Supercapacitors consist primarily of electrode active materials, electrolytes, current collectors, and separators, with the electrode material being the crucial determinant of the capacitor's performance. Activated carbon, thanks to its advantages of a large specific surface area, well-developed pores, and ease of preparation, stands as the pioneering carbon electrode material employed in supercapacitors. By modifying traditional activated carbon, novel and high-performance activated carbon electrode materials can be crafted.
For instance, porous carbon with a remarkable specific surface area of 1200m² · g⁻¹ and a pore capacity of 0.48cm³ · g⁻¹ has been synthesized using polyvinylidene chloride as the precursor, solely through carbonization treatment without any additional post-treatment steps. This material boasts a maximum specific capacitance of 262F · g⁻¹, an electrode density of approximately 0.8g · cm⁻³, and an impressive volume specific capacitance reaching 214F · cm⁻³, positioning it as a promising candidate for supercapacitor electrode materials.
In another study, amorphous activated carbon featuring a porous structure with a specific surface area spanning from 2245 to 2184 m² · g⁻¹ was prepared by carbonizing waste tea leaves and subsequently activating them with KOH. When utilized as an electrode in supercapacitors with a KOH aqueous solution serving as the electrolyte, it exhibited a specific capacitance of up to 330F · g⁻¹. Even after enduring 2000 charge-discharge cycles, the capacitance exhibited only a slight decrease, retaining 92% of its initial value, thereby demonstrating excellent cycling performance.
Furthermore, when lotus pollen is employed as both the carbon source and self-template, and CO2 is used as the activator to prepare activated carbon particles, the resulting activated carbon possesses a unique porous hollow structure composed of a three-dimensional nanogrid skeleton. This specialized activated carbon, when used as an electrode in supercapacitors, achieves a specific capacitance of up to 244F · g⁻¹. Impressively, even after 10,000 charge-discharge cycles, the capacitance remains unchanged, showcasing exceptional durability.