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

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 re...

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Bibliographic Details
Published inJournal of power sources Vol. 196; no. 7; pp. 3426 - 3432
Main Authors COMBELLES, C, YAHIA, M. Ben, PEDESSEAU, L, DOUBLET, M.-L
Format Conference Proceeding Journal Article
LanguageEnglish
Published Amsterdam Elsevier 01.04.2011
Subjects
Applied sciences
Condensed Matter
Direct energy conversion and energy accumulation
Electrical engineering. Electrical power engineering
Electrical power engineering
Electrochemical conversion: primary and secondary batteries, fuel cells
Exact sciences and technology
Materials Science
Physics
Lithium battery
Lithium-ion batteries
Mixed state
Mixedvalence
State
Alkaline storage battery
Secondary cell
Mixed valence
First-principles DFT calculations
Redox mechanisms
Lithium-ion batteries First-principles DFT calculations Redox mechanisms Mixedvalence State
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Summary: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.
ISSN:0378-7753
1873-2755
DOI:10.1016/j.jpowsour.2010.08.065