Mössbauer effect studies of sputter-deposited tin–cobalt and tin–cobalt–carbon alloys

• Published in: Journal of alloys and compounds Vol. 443; no. 1; pp. 114 - 120
• Main Authors: Todd, A.D.W., Dunlap, R.A., Dahn, J.R.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 27.09.2007; Elsevier
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Li-ion batteries; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Mössbauer effect; other γ-ray spectroscopy; Mössbauer spectroscopy; Physics; Sn–Co; Sn–Co–C; Sn–Co; Li-ion batteries; Sn–Co–C; Mössbauer spectroscopy; Sn-Co-C; Cubic lattices; Moessbauer effect; XRD; Electrode material; Nanostructures; Lithium battery; Tin alloys; Carbon alloys; Chemical composition; Sn-Co; Cobalt alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2007.06.030

Sn–Co–C alloys are now used as negative electrodes in the latest generation of Li-ion batteries, although not much is known about the phases present in the materials, their micro or nanostructure nor their physical properties. Here, sputtered combinatorial libraries of Sn 1− x Co x (0 < x < 0.6) and [Sn 0.63Co 0.37] 1− y C y (0.1 < y < 0.5) were studied by 119Sn Mössbauer effect spectroscopy and X-ray diffraction to learn their phase content and micro or nanostructure. The sputtered Sn 1− x Co x films showed the presence of crystalline β-Sn, a new metastable cubic Sn–Co phase, an amorphous Sn 1− x Co x (0.26 < x < 0.45) phase and Co 3Sn 2 as x, or the Co content, increased. The sputtered [Sn 0.63Co 0.37] 1− y C y (0.1 < y < 0.5) materials consist of amorphous grains of Sn 0.63Co 0.37 separated by a carbon matrix. The impact of this nanostructure on the utility of these materials as negative electrodes in Li-ion batteries is discussed.