FeII/FeIII mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Power Sources Année : 2011

FeII/FeIII mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study

Résumé

The iron-based metal-organic-framework MIL53(Fe) has recently been tested as a cathode materials for Li-Ion batteries, leading to promising cycling life and rate capability. Despite a poor capacity of 70mAhg−1 associated with the exchange of almost 0.5Li/Fe, this result is the first evidence of a reversible lithium insertion never observed in a MOF system. In the present study, the MIL53(Fe) redox mechanism is investigated through first-principles DFT+U calculations. The results show that MIL53(Fe) is a weak antiferromagnetic charge transfer insulator at T = 0K, with iron ions in the high-spin S = 5/2 state. Its reactivity vs elemental lithium is then investigated as a function of lithium composition and distribution over the most probable Li-sites of theMOFstructure. The redox mechanism is fully interpreted as a two-step insertion/ conversion mechanism, associated with the stabilization of the Fe3+/Fe2+ mixed-valence state prior to the complete decomposition of the inorganic-organic interactions within the porousMOFarchitecture.

Dates et versions

hal-00523804 , version 1 (06-10-2010)

Identifiants

Citer

Cécil Combelles, Mouna Ben Yahia, Laurent Pedesseau, Marie-Liesse Doublet. FeII/FeIII mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study. Journal of Power Sources, 2011, 196 (7), pp.3426-3432. ⟨10.1016/j.jpowsour.2010.08.065⟩. ⟨hal-00523804⟩
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