Li₃Fe₂(HPO₃)₃Cl: An Electroactive Iron Phosphite as a New Polyanionic Cathode Material for Li-Ion Battery


A novel lithium containing iron-chlorophosphite, Li3Fe2(HPO3)3Cl has been synthesized by employing low melting phosphorous acid flux. The single-crystal X-ray structure determination established that the compound has a 3-dimensional structure built up by edge-shared octahedral dimers and phosphite moieties that create narrow channels along the a- and b-axis. Two crystallographically independent Li ions are located in those channels. The compound was further characterized by TGA, IR, magnetic measurements, and Mössbauer spectroscopy. Magnetic measurements indicate that the compound has a field-induced metamagnetic transition. In this article we report for the first time an iron chloro-phosphite, Li3Fe2(HPO3)3Cl, as a new polyanion-based cathode with a promising electrochemical activity that shows an average voltage of 3.1 V vs. Li+/Li for the Fe2+/Fe3+ redox couple and a reversible capacity of 70 mA h g-1. Details of electrochemical studies including cyclic voltammetry, galvanostatic charge-discharge, and electro-impedance spectroscopy are reported here.



Keywords and Phrases

Cathodes; Crystal structure; Cyclic voltammetry; Electric batteries; Electric discharges; Electrochemical impedance spectroscopy; Electrodes; Iron; Iron compounds; Lithium; Magnetic variables measurement; Secondary batteries; Single crystals; 3-dimensional structures; Electro impedance spectroscopies; Electrochemical activities; Electrochemical studies; Field induced metamagnetic transitions; Galvanostatic charge discharges; Single crystal x-ray structures; Ssbauer spectroscopies; Lithium-ion batteries

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Article - Journal

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© 2015 Royal Society of Chemistry, All rights reserved.

Publication Date

01 Apr 2015