Structural and Electronic Features of Sb-Based Electrode Materials: 121Sb Mössbauer Spectrometry

Hyperfine Interactions - Lithium insertion mechanisms in two antimony based compounds: CoSb3 and CoSb have been studied by means of 121Sb Mössbauer spectrometry. Structural and electronic...     

Electrochemical properties of Ti-Ni-Sn materials predicted by <Superscript>119</Superscript>Sn Mössbauer spectroscopy

The electrochemical activity of TiNiSn, TiNi ₂Sn and Ti ₆Sn ₅ compounds considered as negative electrode materials for Li-ion batteries has been predicted from the isomer shift- Hume-Rothery electronic density correlation diagram. The ternary compounds were obtained from solid-state reactions and Ti ₆Sn ₅ by ball milling. The ¹¹⁹Sn Mössbauer parameters were experimentally determined and used to evaluate the Hume-Rothery electronic density [e _av]. The values of [e _av] are in the region of Li-rich Li-Sn alloys for Ti ₆Sn ₅ and outside this region for the ternary compounds, suggesting that the former compound is electrochemically active but not the two latter ones. Electrochemical tests were performed for these different materials confirming this prediction. The close values of [e _av] for Ti ₆Sn ₅ and Li-rich Li-Sn alloys indicate that the observed good capacity retention could be related to small changes in the global structures during cycling.