Ball-milling of graphite and muilti-wall carbon nanotubes.

The structural modification of graphite and multi-wall carbon nanotubes (MWCNTs) during ball-milling was examined. A comparison of structures after ball-milling was made between graphite and MWCNTs. The ball milling parameters were also examined: milling atmospheres, milling methods, milling mode and the addition of additive materials. In some experiments, hard materials such as alumina or silica were added to graphite and MWCNTs as additives to see whether graphite and MWCTs were shortened by ball-milling. The ball-milling of graphite and MWCNTs with liquid additives reduced the agglomeration of MWCNT and transformed graphite to graphenes. The ball-milling of MWCNTs under impact mode usually resulted in the formation of an amorphous phase, whereas that under friction mode induced the fattening of nanotubes. The results showed that a variety of carbon nanomaterials could be obtained by the proper controlling of ball milling. The structurally modified graphite and MWSNTs are expected to be utilized for energy storage application.