Nanospheres of a New Intermetallic FeSn₅ Phase: Synthesis, Magnetic Properties and Anode Performance in Li-ion Batteries

Abstract

We synthesized monodisperse nanospheres of an intermetallic FeSn(5) phase via a nanocrystal-conversion protocol using preformed Sn nanospheres as templates. This tetragonal phase in P4/mcc space group, along with the defect structure Fe(0.74)Sn(5) of our nanospheres, has been resolved by synchrotron X-ray diffraction and Rietveld refinement. Importantly, FeSn(5), which is not yet established in the Fe-Sn phase diagram, exhibits a quasi-one dimensional crystal structure along the c-axis, thus leading to interesting anisotropic thermal expansion and magnetic properties. Magnetization measurements indicate that nanospheres are superparamagnetic above the blocking temperature T(B) = 300 K, which is associated with the higher magnetocrystalline anisotropy constant K = 3.33 kJ m(-3). The combination of the magnetization measurements and first-principles density functional theory calculations reveals the canted antiferromagnetic nature with significant spin fluctuation in lattice a-b plane. The low Fe concentration also leads Fe(0.74)Sn(5) to enhanced capacity as an anode in Li ion batteries.

Metallic Sn‐Based Anode Materials: Application in High‐Performance Lithium‐Ion and Sodium‐Ion Batteries

“…In 2005, Sony corporation applied the amorphous Sn–Co–C composites as negative electrodes for its new‐type lithium‐ion batteries, named “Nexelion.”17, 18 This breakthrough had ignited great passion from people in researching of Sn‐based alloys. To date, a series of Sn‐based intermetallics alloyed with inactive metals have been investigated as potential anodes for LIBs and/or SIBs, including Fe–Sn,73, 76, 77, 78 Co–Sn,79, 80, 81, 82, 83, 84, 85 Cu–Sn,86, 87, 88, 89 Ni–Sn,23, 90, 91, 92 Mn–Sn,93, 94, 95 La–Sn,96, 97 Ce–Sn,98 Cr–Sn,99, 100 etc.…”

“…Therefore, it is important to find Sn‐based intermetallic compounds with high Sn content. Han's group78, 84, 102 discovered MSn 5 (M = Fe, Co, and Fe 0.5 Co 0.5 ) series intermetallic phases with stoichiometric structural vacancies. Fe 0.74 Sn 5 , Co 0.83 Sn 5 , and Fe 0.35 Co 0.35 Sn 5 exhibit the highest theoretical capacities (>917 mA h g −1 ) among the Sn‐based binary and ternary alloys (M are inactive).…”

“…o,p) Crystal structures of Fe 0.74 Sn 5 and FeSn 2 from [001] direction. Reproduced with permission 78. Copyright 2011, American Chemical Society.…”

Fe-Sn Intermetallic Compound Synthesized via Mechanical Alloying and Liquid Phase Sintering

“…In addition, intermetallic compounds, such as Sn-Ni alloys, Sn-Co alloys, Sn-Cu alloys, and Sn-Fe alloys, are employed to solve the volume expansion problem during discharge/charge (Zhang et al, 2008). In the development of high-performance, lithium ion battery, anode structures (Paul et al, 2005;Richter and Eberhard, 2005), FeSn 2 has been shown to have the best composition among the Fe-Sn intermetallic compounds (Naille et al, 2007;Chamas et al, 2011;Wang et al, 2011). The cycling performance of the FeSn 2 intermetallic compound is constant over 50 cycles at a specific capacity higher than 400 mAhg -1 ; the specific capacity is higher for a FeSn 2 /graphene composite electrode, exhibiting a higher capacity than the conventional carbonaceous anode (372 mAhg -1 ) (Mao and Dahn, 1999;Lee et al, 2010).…”

An interlayer nanostructure of rGO/Sn2Fe-NRs array/rGO with high capacity for lithium ion battery anodes

“…The tin (Sn)-based LIBs anodes, cycling between Sn and Li4.4Sn, exhibit an attractive theoretical specific capacity of 994 mA h g −1 [9]. Moreover, Sn meets the major requirements for replacing the current graphite LIBs anodes owing to its high abundance and non-toxicity [10,11].…”