Investigation of interfacial properties of carbon coated ZnFe2O4 as new anode material for Li-ion batteries

In recent years, the growing need for high specific energy density and good cycling performance has prompted the research to develop novel electrode materials for Li-ion batteries. In this context, carbon coated ZnFe2O4 (C-ZFO) has attracted increasing interest as promising new anode material because it offers an exceptional specific capacity, higher than 1000 mAh g-1, and it is environmentally friendly, non toxic and cheap.1 This electrode material has been used in SIRBATT project in order to investigate the evolution of Solid Electrolyte Interphase (SEI) in this anode because the performances and durability of batteries are strongly influenced by the passivation layer formed on electrode surface.2 The electrodes have been prepared by casting the slurry containing active material, conductive carbon and carboxymethyl cellulose as binder. The electrochemical performances and the study of electrode/electrolyte interface have been investigated by galvanostatic cycles at different C-rate values, Electrochemical Impedance Spectroscopy (EIS) at 25 °C and 50°C and soft X-ray adsorption spectroscopy (XAS) using synchrotron radiation. The electrochemical results have shown that C-ZFO has good cycling performance, with high capacity values also at highest rates, and high stability upon cycling. Furthermore, EIS measurements have reveal that the electrode interfacial stability is more compromised at high temperatures. The XAS results have allowed to obtain important information on SEI formation and evolution upon C-ZFO electrodes. References: 1) Deng Y., Zhang Q.,Tang S., Zhang L., Deng S., Shi Z., Chen G., Chemical Communications., 2011, 47, 6828–6830 2) Di Cicco A., Giglia A., Gunnella R., Koch S. L, Mueller, F., Nobili F., Pasqualini M., Passerini S., Tossici R., Witkowska A., Advanced Energy Materials, 2015, 5, 1500642