Six researchers, Taylan Karakoç, Housseinou Ba, Lai Truong Phuoc, Dominique Bégin, Cuong Pham-Huu, and Sergey N. Pronkin, from the Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES), have proposed ultramicroporous N-doped activated carbon materials for the purpose of developing high-performance supercapacitors.
Leveraging Porous Carbon Electrodes
In supercapacitor technology, using porous carbon electrode materials has garnered attention for their remarkable attributes. These materials demonstrate rapid charge/discharge capabilities and exceptional stability over cycling due to their electrostatic charge storage mechanism. Researchers are exploring avenues to enhance the kinetics of charge/discharge by introducing heteroatoms through doping to amplify their performance further. This modification instigates pseudocapacitance phenomena, resulting in boosted supercapacitor efficiency.
Synthesizing Microporous N-Doped Activated Carbons
The research delves into synthesizing microporous activated carbons doped with nitrogen (N) through a thermochemical activation process. The objective is to create tailored electrode materials for supercapacitors by finely adjusting the final product’s structure and composition. The synthesis conditions and choice of precursor molecules play a pivotal role in this optimization process. A noteworthy achievement is the production of N-doped activated carbons with a controlled specific surface area, ranging from 270 to 1380 m²/g, through the KOH-activation of a sucrose/ammonium citrate mixture. The extent of N-doping was tuned between approximately 1.5 to 7.3 at% by meticulously modifying precursor compositions. The intricate interplay between precursor components and synthesis conditions significantly influences the composition and structure of the synthesized N-doped activated carbons.
Exceptional Supercapacitor Performance
These efforts culminate in an exceptional electrode material for aqueous electrolyte supercapacitors. The optimized N-doped activated carbon demonstrates unparalleled performance characteristics. In a 3-electrode cell with an electrode loading of 0.75 mg/cm² and immersed in a 1M H₂SO₄ electrolyte, the specific capacitance showcases remarkable adaptability across various charging rates. Specifically, the specific capacitance evolves from 359 F/g at a charging rate of 0.5 A/g to 243 F/g at an accelerated rate of 20 A/g. The material’s endurance is equally impressive, as it exhibits minimal degradation, with a mere capacitance loss of less than 0.01% after 1000 charging/discharging cycles. This durability further cements the viability of the optimized N-doped activated carbon as an exceptional electrode material for high-performance supercapacitors.
Through precision in precursor composition and synthesis conditions, this research sheds light on the intricate relationship between material structure, composition, and supercapacitor performance. The resulting tailored N-doped activated carbon opens avenues for elevated supercapacitor efficiency, driving advancements in energy storage technology.
