Fluorographene (FG), which inherits the properties of graphene and fluorographite (FGi), was successfully fabricated through a simple sonochemical exfoliation route in N-methyl-2-pyrrolidone (NMP) and then MgH2-FG composite was prepared by ball milling. The dehydrogenation and rehydrogenation performances of MgH2-FG composite were investigated systematically comparing with as-received MgH2 and MgH2-G composite. It is found that the as-prepared FG exhibited a significant catalytic effect on the dehydrogenation and rehydrogenation properties of MgH2. The MgH2-FG composite can uptake 6.0 wt% H-2 in 5 min and release 5.9 wt% H-2 within 50 mm at 300 degrees C, while the as-received MgH2 uptakes only 2.0 wt% H-2 in 60 mm and hardly releases hydrogen at the same condition. The hydrogen storage cycling kinetics in the first 10 cycles remains almost the same, indicating the excellent reversibility of the MgH2-FG composite. SEM analysis shows that the particle size of MgH2-FG composite was similar to 200 nm, much smaller than that of as-received MgH2 (similar to 20 mu m). TEM observations show that MgH2 particles were embedded in PG layers during ball milling. The dehydrogenation apparent activation energy for the MgH2 is reduced from 186.3 kJ mol(-1) (as-received MgH2) to 156.2 kJ mol(-1) (MgH2-FG composite). The catalytic mechanism has been proposed that F atoms in FG serve as charge-transfer sites and accelerate the rate of hydrogen incorporation and dissociation, consequently enhance the dehydrogenation and rehydrogenation properties of MgH2-FG composite. Furthermore, the PG can inhibit the sintering and agglomeration of MgH2 particle, thus it improves the cycling dehydrogenation and rehydrogenation of MgH2-FG composite. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.