Enhancement of Electrochemical Properties by Freeze-dried Graphene Oxide via Glucose-assisted Reduction

The re-stacking of reduced graphene oxide (rGO) is the main reason to decrease its surface area and the capacitance. A method to prevent graphene sheets from re-stacking is developed in this work by combining glucose filler with a drying process. The rGO/C composite is synthesized via a heat-dry (HD) or freeze-drying (FD) process separately and then thermal reduction under 700 °C. The rGO/C composites are characterized by XRD, SEM, TEM and FTIR. The interspace of the GO sheets increases as the glucose amount increases for the freeze-drying process and re-stacking could be reduced after thermal reduction. The capacitance is evaluated via the cyclic voltammetry method, which the rGO/C composite with freeze-drying and 1 wt% glucose addition (FD-1%) could deliver the highest capacitance 157.6 Fg−1 at 5 mV s−1 scanning rate. This method we developed provides a way to manipulate the interspace of GO sheet and improve the capacitive performance.