Li2MnSiO4 as a potential Li-battery cathode material

Recently we synthesized and preliminary characterized a new material for potential use in Li-battery cathodes: Li 2 MnSiO 4 . Although its theoretical capacity is about 330 mAhg -1 , the actual measurements showed a much smaller value (about 120 mAhg -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 Li 2 MnSiO 4 . Observations of structural changes during the first charge shows a complete loss of peaks when reaching the nominal composition of ca. Li 1 MnSiO 4 . 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.