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URN: urn:nbn:de:swb:90-496842

Li+ intercalation in isostructural Li2VO3 and Li2VO2 with O2- and mixed O2-/F- anions

Chen, R.; Ren, S.; Yavuz, M.; Guda, A.A.; Shapovalov, V.; Witter, R.; Fichtner, M.; Hahn, H.

Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3m) model intercalation materials Li2VO3 and Li2VO2F with O2- and mixed O2-/F- anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic behaviour arising from the different anion environments and the consequent difference in cationic electrostatic repulsion. In comparison with Li2VO3 with an active V4+/5+ redox reaction, the material Li2VO2F with oxofluoro anions and the partial activity of V3+/5+ redox reaction favor higher theoretical capacity (460 mA h g-1vs. 230 mA h g-1), higher voltage (2.5 V vs. 2.2 V), lower polarization (0.1 V vs. 0.3 V) and faster Li+ chemical diffusion (~10-9 cm2 s-1vs. ~10-11 cm2 s-1). This work not only provides insights into the understanding of anion chemistry, but also suggests the rational design of new mixed-anion battery materials.

Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Institut für Angewandte Materialien - Energiespeichersysteme (IAM-ESS)
Institut für Nanotechnologie (INT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2015
Sprache Englisch
Identifikator ISSN: 1463-9076
KITopen ID: 1000049684
HGF-Programm 37.01.13; LK 01
Erschienen in Physical Chemistry Chemical Physics
Band 17
Heft 26
Seiten 17288-17295
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