A two-step chemical-hydrothermal reduction method to prepare reduced graphene oxide with high electrical conductivity

Reduced graphene oxide (rGO) is an important derived graphene with promising potential in many fields. However, the low electrical conductivity has severely limited the further development and application of rGO. Here, a two-step reduction method was developed to produce rGO with high electrical conductivity. The first step is chemical reduction using sodium borohydride (NaBH4) as reducing agent, and the second step is hydrothermal treatment at 180 degrees C. The results show that the chemical-hydrothermal rGO (C-H-rGO) exhibits less defects, excellent thermal stability and high C/O ratio. In particular, C-H-rGO possesses a high electrical conductivity of 1250 S/m, being about 150 times that of chemical rGO (C-rGO) and 25 times that of hydrothermal rGO (H-rGO). Furthermore, the electrode based on C-H-rGO exhibits a high specific capacitance of 180.4 F/g at 1A/g, which is much higher than that of 92.8 F/g for C-rGO and 141.9 F/g for H-rGO. This study provides a new idea for the preparation of high-performance rGO, which is important for the scalable production of graphene materials for supercapacitor electrodes.