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.