Owing to the robust structural topology created by large interstitial voids through 3D-connected polyhedra, anti-NASICON type Fe2(WO4)3 is a promising intercalation electrode material for lithium-ion batteries. The excellent electrochemical cycling performance of this material, resulting from its extremely robust structural topology, makes it a fundamentally interesting material in which to study the mechanism of lithium intercalation. In this presentation, a new solution-based precipitation method for the gram-scale synthesis of anti-NASICON monoclinic Fe2(WO4)3, along with detailed structural, compositional, and morphological characterization is demonstrated. Fe2(WO4)3 undergoes a reversible electrochemical reaction against lithium centered around 3.0 V with capacities near 93% of the theoretical maximum. Structural evolution of Fe2(WO4)3 upon lithium (de)insertion is probed by the combination of in situ X-ray diffraction (XRD) studies, X-ray absorption spectroscopy, and neutron total scattering techniques coupled with symmetry-mode analysis. A two-phase structural transformation from monoclinic to orthorhombic phase is confirmed during lithium intercalation by in situ XRD along with Rietveld refinements, and the mechanism of this structural evolution of monoclinic Fe2(WO4)3 into orthorhombic Li2Fe2(WO4)3 is demonstrated by symmetry-mode analysis.

Investigation of the reversible lithium insertion into anti-NASICON Fe2(WO4)3

253rd National Meeting (2017)

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