Improving the Performance of Biomass-Derived Carbons in Li-Ion Batteries by Controlling the Lithium Insertion Process

Disordered carbons obtained from cherry stones were tested as electrodes for lithium batteries and their properties were compared with those of short multiwalled carbon nanotubes (s-MWCNT), proposed as candidates for use in these electrochemical devices. Cells were cycled (up to 100 cycles) over a wide range of rates (C/10 to 5C). Previously, their structural, textural, and morphological properties were examined by X-ray diffraction patterns, N(2) adsorption data, and electron microscopy images (scanning electron microscopy and transmission electron microscopy), respectively. All carbons exhibited irreversible capacity (IC) to an extent roughly governed by the H/O content among other variables. The best performing carbons were obtained at low calcination temperatures (500 degrees C). Although these conditions can increase IC, the effect can be offset by limiting the amount of Li inserted in the first charge. Moreover, this method improves capacity retention and rate capabilities. This approach allows one to obtain activated carbons with specific capacities of as high as 200 mAh g(-1) at 5C; a high rate indeed. Their performance after as many as 100 cycles over a wide range of charge/discharge rates surpassed that of s-MWCNT and matched that of the best performing carbons reported so far. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3425728] All rights reserved.