Preparation of graphene nanosheets from microcrystalline graphite by low-temperature exfoliated method and their supercapacitive behavior

Abstract

Microcrystalline graphite, a kind of cheap and infrequently used graphite material, used for the rapid synthesis of graphene nanosheets (MGS) by thermal reduction–exfoliation of graphite oxide at low temperature (as low as 100 °C) is reported. The results indicate that the microcrystalline graphite could be oxidized completely. X-ray diffraction patterns show that the obtained MGS exhibit an amorphous structure. Scanning electron microscopy images show that the MGS samples possess nanoporous structure. The results of N2 adsorption–desorption analysis indicate that the MGS samples possess high Brunauer Emmett Teller surface areas (the highest is 374 m2 g−1). The results of electrochemical tests show that the MGS exfoliated at 400 °C (MGS-400) has better supercapacitive performance than that of MGS exfoliated at 100 °C. The specific capacitance value of MGS-400 is about 212 F g−1 at 5 mV s−1. And also the MGS samples have good rate performance and cycle stability.