Self-assembly flower-like porous carbon nanosheet powders for higher lithium-ion storage capacity

Based on the concepts of self-assembly and re-construction, flower-like porous carbon nanosheet powders (CNPs), which exhibit almost double theoretical capacity of prototype graphite powders, are prepared by spray drying a suspension of graphite oxide and cetyltrimethylammonium bromide (CTAB) and subsequent thermally-reducing treatment. The functional groups, edges, and defective sites of nanoscale graphite oxide intermediate and their interaction with CTAB additive are utilized to construct the CNP micro-/nanostructure with abundant wrinkles. This unique micro-/nanostructure not only facilitates coating CNPs on the anode substrate of lithium-ion batteries (LIBs) but also improves their electrochemical performances. Specifically, these CNPs display an initial specific capacity of approximately 807 mAh g(-1) and a stable capacity of approximately 650 mAh g(-1) after the 6th cycle at a charge-discharge current of 100 mA g(-1). And a capacity of approximately 600 mAh g(-1) is still kept after 100 cycles, showing the as-prepared CNPs have promising application in the LIBs. In addition, based on the insertion/extraction 'path-memory effect', a storage mechanism of lithium ions is proposed to explain the importance of wrinkles in the CNPs to the capacity and cycling stability. (C) 2015 Elsevier Ltd. All rights reserved.