N/P co-doped cellulose carbon aerogel with enhanced supercapacitance

Sustainable cellulose has attracted considerable attention in the field of renewable supercapacitor owing to its low-cost and lightweight properties. However, it is still a challenge to enhance their electrochemical performance. Here, nitrogen (N) and phosphorous (P) co-doped carbon aerogels derived from cellulose were synthesized via the sol-gel-lyophilization-carbonization method. Their structures were determined by scanning electron microscopy (SEM), nitrogen sorption isotherm, and X-ray photoelectron spectroscopy (XPS). The N/P co-doped carbon aerogel exhibited significantly enhanced porous surface properties, and the increasing contents of the N and P could provide more defects and active sites. Therefore, the sample achieved a high specific capacitance of 235.5 F g −1 at 0.5 A g −1 , while also demonstrating good retention of specific capacitance with 62.6 % of initial capacitance at 20 A g −1 . The electrode exhibited 87 % capacitance retention and an excellent coulombic efficiency of close to 100 % after undergoing 10,000 cycles at a current density of 6 A g −1 . Overall, the synthesized cellulose carbon aerogels, modified through doping engineering, have been identified as a promising candidate for supercapacitor electrodes.