Details

Autor(en) / Beteiligte

• Brownrigg, Alexander W
• Mountjoy, Gavin
• Chadwick, Alan V
• Alfredsson, Maria
• Bras, Wim
• Billaud, Juliette
• Armstrong, A. Robert
• Bruce, Peter G
• Dominko, Robert
• Kelder, Erik M

Titel

In situ Fe K-edge X-ray absorption spectroscopy study during cycling of Li2FeSiO4 and Li2.2Fe0.9SiO4 Li ion battery materialsElectronic supplementary information (ESI) available. See DOI: 10.1039/c4ta06305h

Erscheinungsjahr

2015-03

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In situ X-ray Absorption Spectroscopy (XAS) results are presented for Li 2 FeSiO 4 and Li 2.2 Fe 0.9 SiO 4 , promising cathode materials for lithium-ion batteries. The aims are to establish the valence and local structure of Fe during charge and discharge to understand if the Fe 3+ /Fe 4+ redox pair can be reached in the current battery design. It is found that the valence state changes between Fe 2+ and Fe 3+ , with no evidence of Fe 4+ before the onset of electrolyte degradation. There is a reversible contraction and extension of the Fe-O bond lengths during cycling while the Fe-Si distance remains constant, which underlines the stability of the Li 2 FeSiO 4 material. The same observations apply to Li 2.2 Fe 0.9 SiO 4 cathode material indicating that changing the stoichiometry does not provide any additional structural stability. The valence and local structures of Fe during battery cycling of Li 2 FeSiO 4 and Li 2.2 Fe 0.9 SiO 4 are studied by in situ (XAS) measurements.