Anode Properties of Composite Thick-Film Electrodes Consisted of Si and Various Metal Silicides

Thick-film electrodes of composite active materials consisted of Si and various metal silicides, FeSi2/Si, VSi2/Si, or MmSi2/Si, were prepared by mechanical alloying followed by gas deposition for anodes of Li-ion batteries. We investigated a relationship between the performance of these electrodes and properties of the silicide, the electrical resistivity, the referential breaking strength, and the thermodynamic stability. The MmSi2/Si composite electrode exhibited superb cycling performance, where the discharge capacity of 380 mA h g-1 was maintained even at the 1000th cycle. It is suggested that thermodynamically stable MmSi2 in the composite electrode can improve the electrical conductivity of the electrode and can release the stress induced by a volumetric change of Si for a long period.