Mechanically alloyed Sn-Fe(-C) powders as anode materials for Li-ion batteries. 1: The Sn{sub 2}Fe-C system

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1391622· OSTI ID:328194

Mao, O; Dunlap, R A; Dahn, J R ^[1]

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1. Dalhousie Univ., Halifax, Nova Scotia (Canada)

The authors have prepared intermetallic phases and mixtures of such phases in the Sn-Fe-C Gibbs` triangle by mechanical alloying methods or by direct melting of elemental powders. This first paper in a three-part series focuses on the materials which fall on the two-phase line connecting Sn{sub 2}Fe and C. Using in situ X-ray diffraction, Moessbauer spectroscopy, and electrochemical methods, the authors show that Sn{sub 2}Fe reacts with Li in Li/Sn{sub 2}Fe cells to form lithium-tin alloys and very small metallic iron grains. The experimental capacity for this reaction is about 800 mAh/g, as expected. During the first charge of such cells about 650 mAh/g of Li can be extracted up to 1.5 V vs. Li. The density of these materials is near 7 g/cm{sup 3}, so first-cycle volumetric capacities near 4500 Ah/L have been attained. It was the hope that the formed iron would act as an electrically conductive, inactive matrix to support the Li-Sn alloy grains and that good cycling behavior would result. However, the extended cycling life of these materials between 1.5 and 0.0 V is poor. On the other hand, reasonable cycle life is obtained if the cycling range is restricted to between 0.0 and 0.55 V, but in this case, the irreversible capacity is about 600 mAh/g and the reversible capacity only about 200 mAh/g. The authors show strategies to overcome these difficulties in the next papers in this series.

• OSTI ID: 328194
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 2 Vol. 146; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
36 MATERIALS SCIENCE
ANODES
BATTERY CHARGING
COMPOSITE MATERIALS
DENSITY
ELECTRICAL PROPERTIES
IRON ALLOYS
IRON CARBIDES
LITHIUM ALLOYS
METAL-NONMETAL BATTERIES
TIN ALLOYS
TIN CARBIDES
VOLTAGE DROP