A room temperature study of the binary lithium-silicon and the ternary lithium-chromium-silicon system for use in rechargeable lithium batteries

Several binary lithium-silicon and ternary lithium-chromium-silicon samples were produced and then characterized by X-ray diffraction, as well as elec trochemical methods at room temperature. The known lithium-silicon phases, as well as silicon-chromium phases, were found, but no ternary phases. The electrochemical characterization of the materials yielded behavior differin g from that predicted from high temperature experiments. Experiments on hig hly lithiated samples yielded charge potentials in the realm of 300-650 mV vs. Li/Li+ and discharge potentials of about 20-300 mV vs. Li/Li+. The bina ry lithium-silicon materials showed reversible capacities of up to 550 mA h /g. The ternary materials showed higher reversible capacity of up to 800 mA h/g. The capacity is dependent on the initial stoichiometry of the materia l with Li:Si ratios of about 1:3.5 showing the highest reversible capacitie s. Good cycling performance could also be achieved. (C) 1999 Elsevier Scien ce S.A. All rights reserved.