Manipulation of Nanoplate Structures in Carbonized Cellulose Nanofibril Aerogel for High-Performance Supercapacitor

The internal structure of carbon aerogels (CAs) is a key factor affecting their electrochemical performance and applications. In this study, the morphology of CAs and their effects on electrochemical properties were investigated via the control of the carbonization temperature. CAs were prepared by freeze-drying combined with high-temperature carbonization using wood cellulose as the raw material. The nanoplate and nanofiber structures of CAs were manipulated via the control of the carbonization temperature. Results revealed that the volume shrinkage as well as independent nanofibers of CAs increase with temperature, but the nanoplate structure decreases. The nanofiber and nanoplate structures affect the specific surface area (SSA) and electrochemical performance of carbon materials. At a temperature of 800 °C, the highest SSA and total pore volume of CAs were observed, with excellent electrochemical stability (after 5000 cycles of cyclic voltammetry testing, it can still keep 89.43% of the original specific capacitance), and a specific capacitance up to 172.7 F g–1. Finally, a symmetrical supercapacitor device was assembled using the CAs, which exhibited a desirable energy density of 4.5 Wh kg–1. And the results obtained from this study can be conducive to the applications of nanoscale CAs in energy storage.