Sustainable nitrogen-doped carbon electrodes for high-performance supercapacitors and Li-ion capacitors
It is still a challenge to design energy storage systems with both high energy density and power density by using low-cost electrodes. Therefore, we propose a successful doped porous carbon synthesis using agricultural waste-ginger straw, which can be fabricated high performance supercapacitors and Li-ion capacitors. Nitrogen doping in the carbon structure improves the wettability and alters the electronic structure, playing a pivotal role in providing extra charge storage capacity. The fabricated ionic liquid-based supercapacitors display an outstanding capacitance of 122 F g-1 at 0.5 A g-1 with a distinguished capacitance retention ratio of 73% at 100 A g-1, an excellent specific energy of 37.8 Wh kg-1 at 374 W kg-1, and a low capacitance loss of 13.5% after 10,000 cycles. Based on LiPF6 electrolyte, the doped carbon as anode shows a high capacity of 1531 mA h g-1 at 0.1 A g-1, and the fabricated Li-ion capacitor exhibits a higher specific energy of 214.6 Wh kg−1 at 373.5 W kg−1, maintains of 63.6 Wh kg−1 at the high specific power of 65.4 kW kg−1, and shows a great cycle performance with 82.7% capacity retention after 10,000 cycles. This work highlights that sustainable doped carbon electrodes are promised to be an advanced energy storage system.