Detecting unalloyed tin in LiSn2(PO4)3-based anodes with Mössbauer spectroscopy

• The first discharge of the Li+ ion anode material LiSn2(PO4)3 was investigated with Mössbauer spectroscopy and electrochemical techniques. Mössbauer spectroscopy provided insight into the structure of the tin atoms of the fully discharged anode materials. Spectra consist of overlapping peaks, which are assigned to noncrystalline β-Sn and Li–Sn alloy domains. An analysis of the relative intensities of the Mössbauer spectra shows the relative abundance of β-Sn increases at the expense of the Li–Sn alloy as the discharge rate increases. Cell polarization occurs at higher discharge rates, leading to inefficient electrode utilization and poor cycling performance. Sluggish Li+ ion diffusion through the amorphous Li3PO4 network that is formed early in the discharge process might be responsible for the poor electrochemical performance and the accumulation of unalloyed tin.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Lithium ion batteries

Anodes

LiSn2(PO4)3

Mössbauer spectroscopy

Chemistry

Kemi

Inorganic Chemistry

Oorganisk kemi

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