In-plane defects produced by ball-milling of expanded graphite

Expanded graphite (EG) was ball-milled in a high-energy planetary-type mill under air atmosphere. The products were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). During the milling process (up to 100 h), the crystallite size (Lc) of EG decreases gradually from 15.4 to 11.3 nm. Compared with most of natural graphite, this Lc decrease degree of EG is far lower. In the EG after ball-milling for 100 h, plenty of in-plane defects are produced, which rarely occur in most of ball-milled natural graphite.