Mechanically alloyed Sn-Fe(-C) powders as anode materials for Li-ion batteries. 3: Sn{sub 2}Fe:SnFe{sub 3}C active/inactive composites

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

DOI:https://doi.org/10.1149/1.1391624· OSTI ID:328196

Mao, O; 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. This third paper in a three-part series focuses on composites of Sn{sub 2}Fe and SnFe{sub 3}C made by mechanical alloying of elemental powders. The Sn{sub 2}Fe and SnFe{sub 3}C grains which comprise the powder particles were about 10 nm in size. Seven samples of composition Sn{sub 2}Fe, 25% (by weight) Sn{sub 2}Fe/75% SnFe{sub 3}C, 24% Sn{sub 2}Fe/72% SnFe{sub 3}C/4% C, 36% Sn{sub 2}Fe/63% SnFe{sub 3}C/1% C, 45% Sn{sub 2}Fe/55% SnFe{sub 3}C, 66% Sn{sub 2}Fe/34% SnFe{sub 3}C, and SnFe{sub 3}C were studied. Using in situ X-ray diffraction and electrochemical methods, the reversible reaction of Li with these materials was studied. The Sn{sub 2}Fe in these materials is an active phase, that is, it reacts completely to form Li{sub 4.4}Sn and Fe, and the SnFe{sub 3}C is an inactive phase, that is, it reacts with very little Li. Thus, since there is a two-phase tie line connecting an inactive and an active phase in the Sn-Fe-C ternary phase diagram, and the fact that mechanical alloying generally produces materials with very small grains, it is possible to produce composites with controlled amounts of active and inactive phases. The best material the authors have made gives a volumetric capacity of about 1600 mAh/cm{sup 3}, has an average voltage near 0.4 V vs. Li metal, and shows stable cycling for over 80 charge-discharge cycles. Materials like this may ultimately replace graphite as the anode of choice for the Li-ion battery.

• OSTI ID: 328196
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 2 Vol. 146; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
36 MATERIALS SCIENCE
ANODES
COMPOSITE MATERIALS
ELECTRICAL PROPERTIES
GRAIN SIZE
IRON ALLOYS
IRON CARBIDES
LITHIUM ALLOYS
METAL-NONMETAL BATTERIES
PHASE STUDIES
TIN ALLOYS
TIN CARBIDES