Structural, magnetic and electrochemical properties of lithium iron orthosilicate

• Published in: Journal of power sources 2006-10, Vol.160 (2), p.1381-1386
• Main Authors: Zaghib, K., Ait Salah, A., Ravet, N., Mauger, A., Gendron, F., Julien, C.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed Matter; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Lithium batteries; Magnetic properties; Optical spectroscopy; Orthosilicate; Physics
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2006.03.023

We report the structural and electronic characterization of Li 2FeSiO 4 synthesized by solid-state reaction. X-ray diffraction, Raman scattering, Fourier transform infrared (FTIR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy and magnetization measurements are analyzed. Magnetic susceptibility experiments give evidence that Li 2FeSiO 4 powders possess an antiferromagnetic ordering below T N = 25 K due to long range Fe–O–Li–O–Fe interactions. Analysis of the paramagnetic region giving the Curie–Weiss parameters θ p = −93.5 K and C p = 4.13 emu K mol −1 shows the divalent state of Fe cations. Electron paramagnetic resonance experiments confirm this electronic configuration. Electrochemical measurements were carried out in lithium cells with LiTFSI in a poly(ethylene oxide) (PEO) polymer electrolyte at 80 °C. The resulting cyclic voltammogram indicates a stable structure for the first cycle with redox peaks at 2.80 and 2.74 V versus Li 0/Li +.