One-pot synthesis of tin-borophosphate-carbon composites as anode materials for Li-ion batteries

Snx(Ca0.05B0.975P0.975O3.95)1−x/C composites as anode material for Li-ion batteries, with x=0.83 and x=0.71 were synthesized by a facile route including cellulose as carbon source. The composites were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and 119Sn Mössbauer spectroscopy. In the latter case, different tin phases were found in the composite including the SnII-based amorphous interface between metallic tin and borophosphate particles that improves the dispersion of the active species. The best electrochemical performances were obtained for x=0.71 that were further improved by ball-milled the composite with a small amount of carbon black. 119Sn Mössbauer spectra of Snx(Ca0.05B0.975P0.975O3.95)1−x/C composites with x=0.83 (a) and x=0.71 (b). [Display omitted]