Carbon-coated SbCu alloy nanoparticles for high performance lithium storage

In this study, carbon-coated SbCu alloy nanoparticles are synthesized via a facile preparation route in high-boiling point solvent. The structure and morphology of carbon-coated SbCu nanoparticles are characterized by scanning electron microscopy, transmission electron microscopy, elemental analysis, X-ray diffraction and Raman spectroscopy, revealing that the obtained particles are composed of intermetallic Cu2Sb and Sb nanocrystallites coated with amorphous carbon. The core shell SbCu/C nanoparticles exhibits excellent performance when employed as anode. The first discharge capacity is 751 mAh g−1 and the initial coulomb efficiency is as high as 71.4%. Capacity fading is very small after 150 lithiation/delithiation cycles, retaining a stable reversible capacity of ∼477 mAh g−1. Moreover, it has a remarkable capacity retention of 87% at a current charge rate of 1C, which is far superior to large size carbon-coated SbCu particles and pure Sb particles prepared under different conditions.