Iron sulphide is an interesting material for a wide range of potential applications due to its number of possible phases, high abundance, low cost and non-toxicity [1]. In particular, Fe-S phases are capable of undergoing reversible electrochemical reactions with lithium-ions making Fe-S a potential material for anodes in lithium-ion batteries [2]. Furthermore, by engineering the electrode materials to nanometre scale, there will be (a) a larger surface area of electrode material in contact with the electrolyte per unit mass, allowing a larger flux of Li-ions between the two electrodes, resulting in faster charging and discharging of the battery; (b) shorter diffusion distances of Li-ions which will result in a higher power density; (c) a better accommodation of strain following conversion reactions, thus resulting in longer cycling life. This advantages are even further strengthened if the nanostructures are synthesised in the two-dimensional form, since then the accessible surface area of the materials is dramatically increased. Despite their superior properties, the scarce number of published reports on the synthesis on two-dimensional FeS nanostructures is remarkable [3].

Here we report structural and chemical characterisation of iron sulphide nanoparticles and two-dimensional nanosheets synthesised using a one-pot, fast and facile single source precursor method. This synthesis method offers the possibility of tailoring the design of the nanostructures with slight variations of the synthesis conditions. Conventional transmission electron microscopy (TEM), high resolution TEM, and selected area electron diffraction patterns confirmed that the nanoparticles consisted of high-crystalline quality troilite FeS; while the nanosheets are made of small crystallites with random rotations while still lying on their (0001) basal plane. Scanning-transmission electron microscopy (STEM) and electron energy-loss spectroscopy confirmed that the majority of the crystallites in the nanosheets are troilite FeS, with some residual pyrite also present; and no oxides were formed during synthesis.  Electrochemical tests also indicate that the nanosheets show much larger capacities compared with the nanoparticles.

1. V. Yufit et al.   Electrochim Acta 50, 417 (2004).
2. A. S. Aricò et al.  Nat Mater.4, 366 (2005)
3. X. Rui et al.  Nanoscale 6, 9889 (2014)

Figures:

(a) Conventional TEM (b) SAED and (c) HRTEM micrographs of a single-source precursor synthesised monocrystal troilite FeS nanoparticle. (d) TEM, (e) SAED and (f) HRSTEM micrographs (FFT in the inset) of the synthesised two dimensional nanosheets; showing their polycrystalline nature.

« Back to The 16th European Microscopy Congress 2016

EMC Abstracts - https://emc-proceedings.com/abstract/structural-and-chemical-characterisation-of-novel-fes-nanostructures-for-energy-storage-synthesised-using-a-single-source-precursor/