Anode performance of mesocarbon microbeads for sodium-ion batteries

The anode performance of mesocarbon microbeads (MCMBs) is tested as they are used in sodium-ion batteries. The MCMBs carbonized at 700 degrees C consist of graphite-like crystallites with an interlayer distance of 357 pm, and with a crystal stack height of 1.61 nm. They deliver an initial charge capacity of 232 mAh g(-1) at a current density of 25 mA g(-1), and keep a reversible capacity of 161 mAh g(-1) after 60 cycles. The MCMB anodes exhibit good reversible sodium insertion/extraction behavior, which results from their internal crystallites and their unique external spherical surface layers. XRD and Raman analyses indicate that the MCMB anode stores energy by the electrochemical intercalation of sodium into the graphene sheets. (C) 2015 Elsevier Ltd. All rights reserved.