▎ 摘　　要

NOVELTY - Exfoliating layered material(M1) to produce nano-scaled platelets involves subjecting (M1) to halogen vapor at above melting/sublimation point of halogen to penetrate interlayer space to form stable halogen-intercalated compound (C1); and either mixing (C1) in liquid medium and sonicating it to exfoliate (C1) to produce platelets and disperse them in the liquid medium or heating (C1) above the boiling point of the halogen, to allow halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. USE - To produce nano-scaled platelets particularly graphene or graphite oxide sheets (claimed) inorganic platelets and nano-scaled platelet-reinforced nano-composites, and dichalcogenides, such as MoS2, which are used as electrodes in lithium ion batteries and as hydro-desulfurization catalysts. ADVANTAGE - The method is environmentally benign and proceeds without using undesirable intercalating chemicals. The method is a relatively low-temperature process and convenient to exfoliate a laminar compound or element to produce nano-scaled platelets (platelets with a thickness smaller than 100 (mostly smaller than 10, typically smaller than 1, i.e. between 0.34-01.02) nm and with relatively uniform thicknesses. The resulting nano-scaled platelets can be readily dispersed in a liquid to form a nanocomposite structure. The process does not involve highly explosive chemical or violent chemical reaction. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. In contrast, to the prior art methods, the present method involves the utilization of halogen species which do not form a residue in the resulting platelets and these species can be readily recovered and re-sued. DETAILED DESCRIPTION - Exfoliating a layered material to produce separated nano-scaled platelets having a thickness smaller than 100 nm, involves a) subjecting layered material to a halogen vapor at a temperature above the melting/sublimation point of the halogen at vapor pressure to cause the halogen to penetrate an interlayer space of the layered material to form a stable halogen-intercalated layered compound (C1) having a halogen concentration of at least 5% in terms of halogen-to-layered material atomic ratio; and either b) heating (C1) above the boiling point of the halogen, to allow the halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets or mixing (C1) in a liquid medium and subjecting it to ultrasonication for exfoliating (C1) to produce platelets and disperse them in the liquid medium. The halogen has a boiling point above 0 degrees C and is selected from diatomic halogen molecules, inter-halogen compounds and/or phosphorus-halogen compounds.