N-doped cellulose-based carbon aerogels with a honeycomb-like structure for high-performance supercapacitors

Derived from abundant biomass, porous carbon materials that have a unique structure, a high specific surface area, and heteroatom doping are promising electrodes for supercapacitors. In this work, using cellulose as the raw material and polypyrrole as the nitrogen source, a porous N-doped carbon aerogel with an interconnected honeycomb-like structure is synthesized by using ice crystals as a template, along with a facile CO2 activation treatment. The carbon aerogels possess a three-dimensional percolation network with a high specific surface area (1196 m2 g − 1) and numerous micropores (0.58 cm3 g − 1), which aid electrolyte penetration and ion storage. In addition, the doped N heteroatoms contribute to a pseudo-capacitance. As a result, the supercapacitor based on the prepared carbon aerogel exhibits a high specific capacitance (160 F g − 1), good charging/discharging rates, and an excellent cycling stability (only 0.18% loss after 3000 cycles). A specific energy up to 21.9 Wh kg−1 is achieved at a specific power of 145 W kg−1 when using a 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte. This work demonstrates that a N-doped, cellulose-based carbon aerogel with an interconnected honeycomb-like percolation structure is a promising electrode material for high-performance supercapacitors.