Gadolinium silicide/silicon composite with excellent high-rate performance as lithium-ion battery anode

Novel composite materials consisted of elemental Si and rare-earth metal silicides, Sm–Si, Gd–Si, and Dy–Si, were synthesized and were evaluated for the first time as a high-performance anode material of Li-ion battery. Thick-film electrodes of the silicide/Si composites were prepared by an arc melting method and a successive gas-deposition method. Among them, the Gd–Si/Si composite electrode exhibited reversible Li-insertion/extraction reactions and the best cycling performance: the initial Coulombic efficiency was 80% and the discharge capacity at the 1000th cycle was 840 mA h g–1. In addition to this, the composite electrode delivered a superb high-rate performance with the capacity of 2100 mA h g–1 even at the high current rate of 12.0 A g–1 (4.8C). The remarkable performances demonstrated that the gadolinium silicide is favorable to significantly enhance anode properties of Si-based composite electrodes.