Structural, magnetic and redox properties of a new cathode material for Li-ion batteries: the iron-based metal organic framework |
| |
Authors: | C Combelles M-L Doublet |
| |
Institution: | (1) Institut Charles Gerhardt, CNRS-UMII-ENSCM-UMI, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France |
| |
Abstract: | The iron-based metal organic framework (MOF) presently studied is the first example of MOF showing a reversible electrochemical
Li insertion with a very good cycling life. Its potential application as a cathode material in Li-ion battery is nevertheless
curbed by a rather poor capacity of 70 mAh/g. To figure out the origin of this limited insertion, first-principles density
functional theory (DFT)+U calculations were performed. The results show that FeIII{OH(BDC)} is a weak anti-ferromagnetic charge transfer insulator at T = 0 K with iron in the high-spin S = 5/2 state. In agreement with the absence of electronic de-localisation along the inorganic chains, lithium insertion leads
to the stabilisation of a FeII/FeIII mixed-valence state of class I or II in the Robin–Day classification, whatever the Li sites considered in the calculations.
Among these Li sites, the most probable site I (OH-Li) and site II (O=CO-Li) are shown to induce incompatible structural changes
on the reduced Li0.5Fe{OH(BDC)} form that could be at the origin of the small capacity measured for this compound.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007. |
| |
Keywords: | First-principles DFT Cathodes Li-ion batteries Magnetism Mixed-valence |
本文献已被 SpringerLink 等数据库收录! |
|