Electrochemical performances of graphene nanosheets prepared through microwave radiation

Graphene nanosheets (GNSs) are prepared by oxidation and rapid expansion of graphite using microwave radiation. The prepared GNSs are characterized using various characterization tools. Morphological characterization using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopic (TEM) studies revealed that the GNSs prepared through microwave radiation are crumbled with scrolled and entangled nature. Raman spectroscopy and X-ray diffraction (XRD) studies confirmed the graphitic crystalline structure of the synthesized GNSs. The surface composition and functional groups introduced on the surface of GNSs due to microwave radiation are corroborated using X-ray photoelectron spectroscopy (XPS) and Fourier transform Infrared Spectroscopy (FT-IR). Electrochemical characterization studies of GNSs based anode materials showed an enhanced lithium storage capacity and fine cycle performance. The initial discharge capacity of GNS electrode is 580 mAh g−1 that decreases to 420 mAh g−1 at 50th cycle. Electrochemical impedance spectral analysis reveals that the exchange current density of GNSs increases with the charge–discharge cycle numbers exhibiting the peculiar electrochemical performance.

► We studied the electrochemical performances of graphene nanosheets prepared through simple, cost effective microwave radiation process.
► Graphene nanosheets based anode materials exhibit stable charge/discharge characteristics of 420 mAh g−1, which is significantly higher than the charge/discharge profiles of natural graphite based electrodes.
► Charge-transfer resistance of graphene electrodes decreases with increasing cycle number implying its enhanced electrochemical activity.