Si-Mn composite anode used for Li-ion battery

Si-Mn composites were prepared by ball-milling a mixture of Si and Mn powders (Si:Mn = 3:5, atomic ratio). The phase structures of the composites were analyzed by X-ray diffraction technology. Their electrochemical performances were investigated via charge-discharge experiments and cyclic voltammetry (CV) by using a cell with a lithium foil as the counter and reference electrode. The XRD patterns show that the materials prepared by 96 h ball-milling under argon atmosphere are composites consisting of Si and Mn powders. Electrodes pressed with different pressures have different cyclic performance. The electrode pressed by 10 MPa has a lithium insertion capacity of 400 mA·h·g^-1 and a charge-discharge efficiency of 72%. Heat treatment enhances the cyclic performance of Si-Mn composites, and the initial lithium insertion capacity decreases with increasing heat treatment temperature. The electrode treated at 350°C has a lithium insertion capacity of 290 mA·h·g^-1 and a charge-discharge efficiency of 68%. After forty cycles, the reversible capacity of the electrode treated at 350°C may retain 192 mA·h·g^-1.