Changes in electrochemical insertion of lithium into glass-like carbon affected by catalytic graphitization at 1000 °C

Abstract

Glass-like carbon spheres produced by activated carbonization of phenol resin in CO 2 atmosphere demonstrated an XRD pattern typical for disordered carbons. This material was entirely useless as anode for lithium-ion cell because of both its extremely low discharge capacity (27 mAh/g) and cyclic reversibility for the first cycle (39%). Heat treatment of the original carbon at temperature 2700 °C appeared to be ineffective for obtaining graphite material. The product of such a treatment yielded discharge capacity of 74 mAh/g, which remained at an unacceptably low level. A simple heat treatment of disordered carbon with iron powder at relatively low temperature of 1000 °C allowed us to improve electrochemical behaviour of the carbon. Due to a partial transformation of glass-like carbon into graphite, discharge capacity increased to about 250 mA/g.