Structure, Shift in Redox Potential and Li-Ion Diffusion Behavior in Tavorite LiFe1−xVxPO4F Solid-Solution Cathodes
AbstractSolid-solution Li-ion cathode materials transform through a single-phase reaction thus leading to a long-term structural stability and improved cyclability. In this work, a two- to single-phase Li+-extraction/insertion mechanism is studied through tuning the stoichiometry of transition-metal Fe/V cations to trigger a transition in the chemical reactivity path. Tavorite triclinic-structured LiFe1−xVxPO4F (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) solid-solution powders were prepared by a facile one-step solid-state method from hydrothermal-synthesized and commercial raw materials. The broad shape of cyclic voltammetry (CV) peaks, sloping charge/discharge profiles and sloping open-circuit voltage (OCV) profiles were observed in LiFe1−xVxPO4F solid-solution cathodes while 0 < x < 1. These confirm strongly a single-phase behavior which is different from the two-phase behavior in the end-members (x = 0 or 1). The electronegativity of M (M = Fe1−xVx) for the redox potential of Fe2+/3+ couple or the M–O4F2 bond length for the V3+/4+ couple plays respectively a dominant role in LiFe1−xVxPO4F solid-solution cathodes. View Full-Text
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Yan, J.-L.; Shao, G.-Q.; Fan, S.-H.; Zhu, C.; Zhang, Y.; Wang, J.; Liu, Q. Structure, Shift in Redox Potential and Li-Ion Diffusion Behavior in Tavorite LiFe1−xVxPO4F Solid-Solution Cathodes. Molecules 2019, 24, 1893.
Yan J-L, Shao G-Q, Fan S-H, Zhu C, Zhang Y, Wang J, Liu Q. Structure, Shift in Redox Potential and Li-Ion Diffusion Behavior in Tavorite LiFe1−xVxPO4F Solid-Solution Cathodes. Molecules. 2019; 24(10):1893.Chicago/Turabian Style
Yan, Jia-Li; Shao, Gang-Qin; Fan, Shu-Hao; Zhu, Can; Zhang, Yong; Wang, Jun; Liu, Qi. 2019. "Structure, Shift in Redox Potential and Li-Ion Diffusion Behavior in Tavorite LiFe1−xVxPO4F Solid-Solution Cathodes." Molecules 24, no. 10: 1893.
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