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 Li 2 FeSiO 4 and Li 2.2 Fe 0.9 SiO 4 Li ion battery materials

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2015, Vol.3 (14), p.7314-7322

Erscheinungsjahr

2015

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.