Influence of different electrolytes on the formation of electrochemically exfoliated graphene and their supercapacitor performance
摘要
The influence of different electrolytes, such as 1 M NaOH, KOH and Na2SO4, was investigated for the large-scale production of graphene nanosheets (GNs) from graphite sheets via electrochemical exfoliation at room temperature. The main advantage of this method lies in its ability to produce defect-free graphene nanosheets compared to conventional chemical and physical approaches. The synthesized GN was characterized using X-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FE-SEM). The results revealed that 1 M KOH serves as the most effective alkaline medium for the electrochemical exfoliation of graphite, yielding high-quality graphene nanosheets. The resulting GN shows great potential as an electrode material for electrochemical energy conversion and storage devices. The electrical double-layer capacitor (EDLC) performance of the GN electrode was evaluated in a Li2SO4 electrolyte. The GN synthesized using 1 M KOH exhibited a high specific capacitance of 170 F g⁻1 and superior electrochemical reversibility compared to those obtained using 1 M NaOH and 1 M Na2SO4. Finally, a symmetric supercapacitor device (GN-KOH||GN-KOH) was fabricated using Li2SO4 as the electrolyte, which delivered a high specific energy of 15.6 Wh kg⁻1 at a working potential of 1.6 V.