Electrochemical impedance characterization of FeSn2 electrodes for Li-ion batteries

This work reports the electrochemical characterization of a micro-scale FeSn2 electrode in a lithium battery. The electrode is proposed as anode material for advanced lithium ion batteries due to its characteristics of high capacity (500 mAh g−1) and low working voltage (0.6 V vs. Li). The electrochemical alloying process is studied by cyclic voltammetry and galvanostatic cycling while the interfacial properties are investigated by electrochemical impedance spectroscopy. The impedance measurements in combination with the galvanostatic cycling tests reveal relatively low overall impedance values and good electrochemical performance for the electrode, both in terms of delivered capacity and cycling stability, even at the higher C-rate regimes.

► In this paper we study a tin based, FeSn2, high capacity lithium-alloying electrode.
► The electrochemical performance of this electrode in lithium batteries is remarkably influenced by the current rate.
► This aspect is investigated by electrochemical techniques such as galvanostatic cycling and impedance spectroscopy.
► The results demonstrated that the good electrochemical behavior of the electrode at the higher currents is due to the formation of a stable solid electrolyte interphase (SEI) film.