Exfoliation and reduction of graphene oxide at low temperature and its resulting electrocapacitive properties

Low-temperature reduced graphene oxide (LT-RGO) powder with full exfoliated morphology was achieved directly from freeze-dried graphite oxide (GO) aqueous solution in air atmosphere, which is simple and energy-saving. For explaining this phenomenon, the microstructure and thermal behavior of freeze-dried GO and vacuum filtered GO film was compared. Moreover, the thermal-induced reduction process of freeze-dried GO has been in situ monitored by temperature-dependent infrared spectroscopy. The results show that freeze-dried GO demonstrates the floc morphology with larger interlayer distance than that of vacuum filtered GO film, which should be the essential reason for its low-temperature reduction and exfoliation behavior. The dispersibility and capacitance property of as-prepared LT-RGO has also been investigated. At current density of 6 A g(-1), the specific capacitance of 460 F g(-1) was achieved, shows that the prepared LT-RGO holds great application potential in electric energy storage.