On the electrochemical performance of anthracite-based graphite materials as anodes in lithium-ion batteries

The electrochemical performance as potential negative electrode in lithium-ion batteries of graphite materials that were prepared from two Spanish anthracites of different characteristics by heat treatment in the temperature interval 2400-2800 degrees C are investigated by galvanostatic cycling. The interlayer spacing, d(002), and crystallite sizes along the c axis, L-a, and the a axis, L-a, calculated from X-ray diffractometry (XRD) as well as the relative intensity of the Raman D-band, I-D/I-t, are used to assess the degree of structural order of the graphite materials. The galvanostatic cycling are carried out in the 2.1-0.003 V potential range at a constant current and C/10 rate during 50 cycles versus Li/ Li+. Larger reversible lithium storage capacities are obtained from those anthracite-based graphite materials with higher structural order and crystal orientation. Reasonably good linear correlations were attained between the electrode reversible charge and the materials XRD and Raman crystal parameters. The graphite materials prepared show excellent cyclability as well as low irreversible charge; the reversible capacity being up to similar to 250 mA h g(-1). From this study, the utilization of anthracite-based graphite materials as negative electrode in lithiumion batteries appears feasible. Nevertheless, additional work should be done to improve the structural order of the graphite materials prepared and therefore, the reversible capacity. (C) 2009 Elsevier Ltd. All rights reserved.