In situ Raman spectroscopic analysis of the lithiation and sodiation of antimony microparticles

A one-pot sol-gel autocombustion synthesis for carbon coated antimony microparticles has been developed. The initial capacities of this material were 647 mAhg−1Sb vs. Li and 527 mAhg−1Sb vs. Na, with a rate capability (8C: 398 and 356 mAhg−1Sb vs. Li and Na respectively) and cyclability (cycle 120 capacity retention: 86% vs. Li, 91% vs. Na). The sol-gel synthesised Sb was found to be superior to commercial Sb of similar particle size (ca. 5-50 μm), which is attributed to carbon coating. In situ Raman analysis revealed differences between the sol-gel synthesised and commercial antimony materials, regarding their reversibility, during the 1 st cycle, and additionally demonstrated that upon charge both materials do not return to a crystalline material, but instead to an amorphous phase represented by a broad feature centred at ca. 140 cm−1.