The γ-Brass Type Cu–rich Complex Intermetallic Phase Cu41Sn11: Structure and Electrochemical Study

Abstract

γ-Brass type phase Cu41Sn11 in binary Cu–Sn system has been reinvestigated. The title phase was synthesized by the conventional high-temperature solid-state method, and structural characterization was carried out using X-ray diffraction. The compound crystallizes in F4‾3m space group (No 216). These structures are constructed of four independent 26-atom γ-clusters per primitive unit cells and centered at the four high symmetry points of the unit cell. The compound exists in a narrow homogeneity range. First-principles quantum mechanics computation was employed on the ordered model Cu41Sn11 shows that the phase is stabilized by the Hume-Rothery mechanism. The copper-rich binary stannide, Cu41Sn11 phase, displays excellent cycle stability during fast charging/discharging rates as an anode in Li-ion batteries. It shows charge/discharge retention capacities of 94.5% and 87.1%, respectively, from the 2nd cycle onwards. The excess Cu-content has successfully assisted in the stable interphase formation and subdued the mechanical stress evolving from volume expansion. The first time such a poly-crystalline Cu-rich, cubic, Cu41Sn11 phase has shown any Li-ion insertion activity for rechargeable Li-ion batteries at ambient temperature.

Department(s)

Chemistry and Biochemistry

Document Type

Article

DOI

https://doi.org/10.1016/j.solidstatesciences.2021.106682

Keywords

Anode material, Atomic ordering, Electronic structure calculations, Gamma brass, Li-ion batteries, X-ray diffraction

Publication Date

9-1-2021

Journal Title

Solid State Sciences

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