Li2MnSiO4 as a potential Li-battery cathode material

Recently we synthesized and preliminary characterized a new material for potential use in Li-battery cathodes: Li2MnSiO4. Although its theoretical capacity is about 330 mAh g(-1), the actual measurements showed a much smaller value (about 120 mAh g(-1)). One of the reasons for the poor performance could be the poor electronic conductivity (<10(-14) S cm(-1) at RT) causing a huge polarization during charge-discharge. However, in the present paper we show that reducing the particle size down to the range of 20-50 nm and additional particle embedment into a carbon phase does not significantly improve the electrochemistry of Li2MnSiO4. Observations of structural changes during the first charge shows a complete loss of peaks when reaching the nominal composition of ca. Li1MnSiO4. The peaks are not recovered during subsequent cycling. It is supposed that extraction of Li causes significant structural changes so that the resulting material is only able to reversibly exchange a limited amount of Li. (c) 2007 Elsevier B.V. All rights reserved.