Submicron silicon anode stabilized by single-step carbon and germanium coatings for high capacity lithium-ion batteries

Abstract

Stabilization of micro/submicro sized silicon anode has been a challenge for its commercial application as high capacity electrode. Here, we demonstrate a single-step, low temperature (580 °C) synthesis of Si@Ge@C core-shell electrode which can stabilize the micro/submicro Si electrode, and offer high capacity and long life. The Si@Ge@C electrode delivered high specific capacity of ∼900 mAh/g at the current density of 2 A/g for the composition of 34.2 wt% C, 39 wt% Si, and 26.8 wt% Ge with over 80% capacity retention after 200 cycles. The C and Ge rich electrodes were mostly spherical in shape and were able to preserve the pre-cycling morphology even after 10 cycles at low current density of 200 mA/g. Irrespective of the initial electrode morphology, the core-shell architecture offered better cyclic stability than that of the bare Si electrode.