Structural transformations in lithiated Mn2Sb electrodes probed by Mössbauer spectroscopy and X-ray diffraction

The electrochemical reactions of Li with Mn₂Sb and small amounts of MnSb have been investigated by Mössbauer spectroscopy and X-ray diffraction. The lithiation transforms initially the MnSb part and later the Mn₂Sb part into amorphous LiMnSb. On further lithiation the LiMnSb phase transforms to rather well crystallized Li₃Sb. In the X-ray diffraction pattern for the fully lithiated sample extruded nanocrystalline Mn is seen for the first time in these type of electrodes. The first delithiation of Li₃Sb results in a mixture of three phases Mn₂Sb, MnSb and LiMnSb. After several cycles (charges and discharges) of the electrode the Mn₂Sb phase disappears completely.