A new method of Fe2(WO4)3 preparation and its thermal stability

Investigating the Mechanism of Reversible Lithium Insertion into Anti-NASICON Fe2(WO4)3

“…20 Following this work, there have been a handful of successful examples of lower-temperature synthesis of monoclinic Fe 2 (WO 4 ) 3 through solution-based precipitation methods. 22,23 The difficulty in preparing phasepure monoclinic Fe 2 (WO 4 ) 3 arises from its thermal instability at high temperatures, with traditional solid-state routes leading to the formation of the thermodynamically stable FeWO 4 phase via disproportionation. 20,23 Previous routes to monoclinic Fe 2 (WO 4 ) 3 using solution precipitation methods relied on the use of a Na 2 WO 4 precursor, which can lead to sodiuminserted products.…”

“…22,23 The difficulty in preparing phasepure monoclinic Fe 2 (WO 4 ) 3 arises from its thermal instability at high temperatures, with traditional solid-state routes leading to the formation of the thermodynamically stable FeWO 4 phase via disproportionation. 20,23 Previous routes to monoclinic Fe 2 (WO 4 ) 3 using solution precipitation methods relied on the use of a Na 2 WO 4 precursor, which can lead to sodiuminserted products. 22 Therefore, we developed an alternative precipitation approach using (NH 4 ) 10 W 12 O 41 •xH 2 O and Fe(NO 3 ) 3 •9H 2 O as the starting materials.…”

“…Direct thermal annealing at 600 °C or thermal annealing above 650 °C results in the decomposition of Fe 2 (WO 4 ) 3 into FeWO 4 and WO 3 instead of a phase transition from the monoclinic phase into a high-temperature orthorhombic phase, as is the case for the molybdate. 23 This synthetic approach results in the preparation of large quantities of phase-pure Fe 2 (WO 4 ) 3 , with isolated ceramic yields of 95%.…”

“…22 Sriraman and Tyahi confirmed this assignment and reported the thermal decomposition of Fe 2 (WO 4 ) 3 to FeWO 4 and WO 3 at temperatures above 750 °C. 23 Monoclinic Fe 2 (WO 4 ) 3 crystallizes into a 3D structure consisting of corner-sharing FeO 6 octahedra and WO 4 tetrahedra. 22 In contrast to the isostructural Fe 2 (MoO 4 ) 3 , the tungstate congener does not have a high-temperature orthorhombic polymorph.…”

“…22 In contrast to the isostructural Fe 2 (MoO 4 ) 3 , the tungstate congener does not have a high-temperature orthorhombic polymorph. 23 To date, the structural aspects of lithium intercalation into Fe 2 (WO 4 ) 3 have only been investigated by Goodenough and co-worker through chemical insertion with ex situ powder X-ray diffraction (XRD). 24 They showed that chemical Li + insertion into Fe 2 (WO 4 ) 3 results in a fully lithiated Li 2 Fe 2 (WO 4 ) 3 phase that crystallizes into a structure indexed to an orthorhombic (Pbcn) space group in the same way as the molybdate.…”