Preparation of re-constructed carbon nanosheet powders and their efficient lithium-ion storage mechanism

Based on the re-construction idea of carbon nanomaterials, novel folding re-constructed carbon nanosheets (re-CNSs) with unique microstructure and higher lithium-ion storage capacity than prototype graphite powders are prepared. The nanoscale carbon-fragment suspension is firstly prepared through a successive chemical oxidation of graphite and ultrasonic crushing operation, and the re-CNS powders are then obtained by spray drying the suspension and a subsequent high-temperature reducing process. The as-prepared re-CNSs exhibit a folding appearance with a width of several micrometers, with a maximum initial specific capacity of 903 mAh.g(-1) for the re-CNSs sample thermally reduced at 500 degrees C (re-CNSs500). After 100 cycles, the reversible capacity is maintained at about 400 mAh g(-1) for the re-CNSs500. The abundant carboxylic and hydroxide groups, edges, and defective sites of individual graphite oxide fragments facilitate the dislocation formation in the re-CNSs. In addition, a dislocation mechanism is thus used to describe the enhanced lithium-ion storage. (C) 2015 Elsevier Ltd. All rights reserved.