A Novel Intercalation Cathode Material with 1.7 Li per Transition Metal

Monday, 6 October 2014: 10:30
Sunrise, 2nd Floor, Galactic Ballroom 2 (Moon Palace Resort)
R. Chen (Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT)), S. Ren (Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT)), M. A. Cambaz (Helmholtz Institute Ulm for Electrochemical Storage (HIU)), H. Hahn (Institute of Nanotechnology, Karlsruhe Institute of Technology, Helmholtz Institute Ulm for Electrochemical Storage (HIU)), and M. Fichtner (Helmholtz Institute Ulm (HIU), Germany, Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Germany)
Vanadium-based materials have received considerable attention for lithium ion batteries due to the facts that vanadium is the fifth most abundant transition metal in the earth’s crust, its relatively low atomic mass, its multiple oxidation states. The redox operating voltage (typically < 4.5 V) of vanadium-based materials is typically within the stability limit of conventional electrolyte, and vanadium oxides have rich crystal structures [1]. The ability of layered V2O5 for Li+ insertion has been well characterized. Intercalation of one Li+ per formula unit corresponds to a specific capacity of 147 mAh g-1. Further Li+ ions (x > 1 in LixV2O5) insertion may cause irreversible structural transformations [2].
In this work, a new high-capacity (> 400 mAh g-1) and high energy density (> 1000 Wh kg-1) cathode material comprising of lithium metal oxyfluoride with a representative composition of Li2VO2F has been synthesized through a mechanical ball-milling method. In comparison with the prior art, several remarkable features of this new compound Li2VO2F are (i) two-electron reaction based on V3+/V5+ is accessible per transition metal, (ii) the initial composition is at lithiated state, (iii) it has a high theoretical specific capacity of 462 mAh g-1. Furthermore, in comparison with the start-of-the-art commercial cathode materials, this new material offers the opportunity to reach higher capacity and energy density.


[1] N. A. Chernova, M. Roppolo, A. C. Dillon, M. S. Whittingham, J. Mater. Chem. 2009, 19, 2526
[2] C. Delmas, H. Cognac-Auradou, J. M. Cocciantelli, M. Ménétrier, J. P. Doumerc, Solid State Ion. 1994, 69, 257.