Porous and three-dimensional carbon aerogels from nanocellulose/pristine graphene for high-performance supercapacitor electrodes

Bio-based materials with good electrical properties produced by environmentally friendly methods have been increasingly applied in battery and supercapacitor technologies. In this work, we used 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCN) and pristine graphene (PG) as precursors to fabricate three-dimensional (3D) carbon aerogels with outstanding conductivity via freeze-drying followed by carbonization. The specific capacitance of the carbonized TOCN/PG (CTG) aerogels reached 134.09 F/g at a current density of 0.5 A/g. Meanwhile, a better cycling stability was achieved and the capacitance retained 98.89 % after 5000 cycles. As the temperature increased to 1100 °C, the electrochemical performance of the carbonized TOCN aerogel (CTOCN-1100) electrode was improved significantly with a specific capacitance of 361.74 F/g at a current density of 0.5 A/g, and the capacitance still retained as high as 99.3 % after 5000 cycles. Therefore, these bio-based cellulose nanofibrils are promising in the field of supercapacitors.