Supporting Information

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1 Supporting Information Wiley-VCH Weinheim, Germany

2 Mixed valence Li/Fe-based MFs with both reversible redox and sorption properties G. Férey 1, F. Millange 1, M. Morcrette 2, C. Serre 1, M.-L. Doublet 3, J.-M. Grenèche 4 and J.-M. Tarascon* 2 1 Institut Lavoisier - UMR 8180 Université de Versailles St-Quentin-en-Yvelines 45 Avenue des Etats-Unis, Versailles, France 2 LRCS-CNRS 6007 Université de Picardie Jules Verne 33, rue Saint-Leu, Amiens, France 3 LSDSMS-CNRS 5636 Université Montpellier II Place E. Bataillon, Montpellier, France 4 LPEC- CNRS 6087 Université du Maine- Avenue livier Messiaen, Le Mans, France SYNTHESIS. MIL-53(Fe)_H 2 was solvothermally synthesized (autogenous pressure) from an equimolar amount of iron(iii) perchlorate hydrate Fe(Cl 4 ) 3.xH 2 (Aldrich, 97%), 1,4-Benzenedicarboxylic acid H 2 C- (C 6 H 4 )-C 2 H (Alfa 97%), Hydrofluoric acid HF (Prolabo, 40%) in N,N -dimethylformamide (DMF, Aldrich 99%). Reactants were stirred a few minutes before introducing the resulting suspension in a Teflon-lined steel autoclave and the temperature set at 423 K for three days. The light orange MIL-53(Fe)_H 2 powder was finally obtained after dispersion of the solvothermally synthesized powder into a large amount of water for 2 hours. A laboratory powder X-ray diffraction pattern showed that a novel crystalline phase has been produced. STRUCTURE DESCRIPTIN. The structure of the new material was solved from laboratory powder X-ray diffraction data. A determination of the peak positions was carried out by means of the WinPLTR program. [1] Pattern indexing was then performed by means of the computer program DICVL04 [2] from the first twenty lines. Satisfactory figures of merit were thus obtained for this compound. It appeared that MIL-53(Fe)_H 2 has shown cell parameters close to those of the chromium analogue MIL-53lt or Cr III (H)( 2 C-C 6 H 4 -C 2 ).(H 2 ) recently isolated by our group. [3, 4] MIL-53(Fe)_H 2 crystallizes with a centered monoclinic cell [a=21.080(1) Å, b=7.618(1) Å, c=6.810(1) Å, β=114.89(1) and V=992.1(2)Å 3 ]. The corresponding atomic coordinates of MIL-53lt were then used as starting model in the Rietveld refinement for MIL-53(Fe)_H 2. The use of soft distance and angular constraints was used to regularise the structural model. Hydrogens atoms from the organic molecules and the hydroxyl group were placed in calculated positions and treated as riding (C-H = 0.93 Å and -H = 0.82 Å), further optimized through first-principles structural relaxations. Within this structure the Fe 3+ cation is six-fold coordinated in distorted octahedral geometry and the octahedral Fe- centers are linked by sharing trans-hydroxyl groups forming bent M-(H,F)-Fe chains. The oxygen atoms of the BDC moieties occupy the equatorial positions of the M 4 (H,F) 2 octahedra while the H,F group occupies the shared position between adjacent octahedra along the chain. The axial oxygen atom corners are shared by neighboring octahedral to form a zigzag ---H-Fe 3+ -H-Fe backbone. The metal oxide chains in this phase are parallel to

3 each other and are cross-linked by the di-anions to form a framework with an array of 1-D diamond-shaped channels. Each channel is delimited by four walls of benzyl units and four chains of corner-shared octahedra. Finally, the water molecules are located at the centre of the pores, interacting through hydrogen bonds with the hydroxyl groups of the inorganic network. Using a similar approach the X-Ray pattern of MIL-53(Fe)_EC- DMC has been indexed in a centered orthorhombic cell [a=16.187(1) Å, b=13.980(1) Å, c=6.903(1) Å and V=1562.1(2) Å 3 ] and space group Imcm. However, no attempts were conducted to precisly determine the position of the EC and DMC molecules within the unit cell. ELEMENTARY ANALYSIS. Quantitative elemental analyses performed on the MIL-53(Fe)_H 2 solid gave the following results : Fe: 23.7%; C: 35.6%; H: 2.68% and F: 1.31%. These values compare well with those calculated from the proposed formula Fe III (H) 0.8 F 0.2 ( 2 C-C 6 H 4 -C 2 ).(H 2 ): Fe: 21.9%; C: 37.6%; H: 2.68% and F: 1.48%. THERMGRAVIMETRY ANALYSIS. TGA experiments were performed under 2 for both MIL- 53(Fe)_H 2 and MIL-53(Fe)_EC-DMC samples using a TA-Instrument type 2050 analyzer apparatus. For the former, two weight losses of 6.97 % (cal: 7.06%) below 373 K and % (cal: 61.62%) above 573 K corresponding respectively to the departures of the free water molecules and bound terephthalic acid were observed, while for the latter there is a initial weight loss of % below 423 K corresponding to the departure of one EC-DMC/Fe (cal: 27.32%) and a second one of % above 573 K corresponding to the bound terephthalic acid (cal: 48.19%). In both cases the residual solid has been identified as poorly crystallized iron oxide Fe 2 3. These losses are on the whole in agreement with the theoretical values (total loss: % for the water containing phase) and (total loss: % for the water containing phase). INFRARED SPECTRSCPY. The Infrared spectra of the title compound MIL-53(Fe)_H 2 clearly shows the presence of the vibrational bands characteristic of the framework -(-C-)- groups around 1530 and 1390 cm -1 confirming the presence of the dicarboxylate within the solid; Another band around 3610 cm -1 also confirmed the presence of H and/or H 2 groups. Infra-Red spectroscopy has also shown the existence of free - C= bands around 1800 cm -1 and -C--C- bands around 1070 cm -1 charateristics of the EC-DMC moieties, in MIL-53_EC-DMC. ELECTRCHEMICAL TESTS. Swagelok-type cells were assembled in an argon filled glove box at a dew point of 80 C, by utilizing a Li metal disc as the negative electrode, a Whatman GF/D borosilicate glass fiber sheet saturated with a 1 M LiPF 6 in ethylene carbonate (EC), dimethyl carbonate (DMC) (1:1 in weight) as the electrolyte, and a positive electrode made by mixing Fe III (H) 0.8 F 0.2 ( 2 C-C 6 H 4 -C 2 ) powders with 15% (weighed) carbon black (SP). Usually, 10 to 12 mg of the mixed powders was placed on top of the Swagelok plunger. The lithium reactivity was monitored with a "Mac-Pile" potentiostat/galvanostat (Biologic SA, Claix, France). Electrochemical tests were realized using a potential window between 1.5 and 3.5 V vs. Li + /Li 0 and a cycling rate of C/10 (that is one lithium per formula unit in 10 hours).

4 IN SITU X-RAY. The in situ X-ray diffraction electrochemical cells, assembled similarly to our Swagelok cell, but having a beryllium window as current collector on the M side, were placed on a SIEMENS D8 diffractometer (CoK α = Å) equipped with a PSD detector, and connected to the Mac-Pile system. wing to our in situ x-ray cell design, we could extend our 2θ data collection down to 8 and hence monitor the most intense low angle Bragg peaks. The lattice parameters and the space group determinations were performed using the program Fullprof. [5] MÖSSBAUER SPECTRSCPY. 57 Fe Mössbauer spectra were recorded in transmission geometry in the constant acceleration mode and a 57 Co(Rh) source of a nominal activity of 925MBq. The velocity scale was calibrated at room temperature with an α Fe foil. The hyperfine parameters δ (isomer shift) and E q (quadrupole splitting) were determined by fitting Lorentzian lines to the experimental data, using the MSFIT program (J. Teillet and F. Varret, unpublished MSFIT program, University of Le Mans France). Isomer shift values are given with respect to that of α-fe. To perform these experiments, the cells, once cycled down to the required voltage, were stopped and opened in a dry box. The partially powdered lithiated material was recovered and washed with dimethyl carbonate (DMC) prior to being placed into a sealed aluminium plastic bag to carry-out the measurements. These samples were then placed either at room atmosphere or under helium gas in a bath cryostat to perform 300K and 77K Mössbauer spectra, respectively. SRPTIN STUDIES. They were performed using the in situ X-ray cell hardaware that was loaded inside the dry box by depositing 100 mg of water-free Fe III (H) 0.8 F 0.2 ( 2 C-C 6 H 4 -C 2 ) powders onto the beryllium window and by adding 2 cm 3 of electrolytes. The cell was tied, removed from the dry box and then placed on a D8 diffractometer. Data scans were collected as a function time and the collection was stopped once the X-ray powder patterns were no longer evolving. Besides, providing informations about the sortion kinetics, such experiments enable to determine the structural parameters for the swelled phases. This data shows again the very high breathing ability of the Fe III (H) 0.8 F 0.2 ( 2 C-C 6 H 4 -C 2 ) associated to the capturing of a wide classes of organic molecules.

5 Electrolytes Space a (Å) b (Å) c (Å) b Cell (Solvents + 1M Salts) Group Volume Anhydrous phase C2/c A 3 Solvent H 2 C2/c A 3 DMC I m c m A 3 DMC;LiPF 6 I m c m A 3 EC-DMC I m c m A 3 EC-DMC; LiPF 6 I m c m A 3 EC-DMC; LiBF 4 I m c m A 3 EC; LiPF 6 P n a m A 3 EC-PC P n a m A 3 EC-PC; LiPF6 P n a m A 3 PC P n a m A 3 PC; LiPF 6 P n a m A 3 EC-PC; LiTFSI P n a m A 3 DEC I m c m A 3 DMC : DiMethyl Carbonate V 82 A 3 EC : Ethyl Carbonate : V 80 A 3 PC : Propylene Carbonate : V A 3 DEC : Diethylene Carbonate EC-DEC I m c m A 3 EC-DEC; LiPF 6 I m c m A 3 V A 3 THF;LiPF 6 P n a m A 3 THT : Tetrahydrofurane THF P n a m A 3 ELECTRNIC STRUCTURE CALCULATINS. Electronic structure calculations including full structural relaxations were performed using the self-interaction corrected density functional theory formalism (DFT+U) as implemented in the Vienna Ab Initio Simulation Package (VASP) code. [6] Atoms were treated using the PAW potentials within the GGA-PBE functional for exchange and correlation energies. [7, 8] Spin-polarized calculations were used to account for the different magnetic structures.

6 REFERENCES [1] T. Roisnel, J. Rodriguez-Carvajal, in Epdic 7: European Powder Diffraction, Pts 1 and 2, Vol , 2001, pp [2] A. Boultif, D. Louer, J. Appl. Crystallogr. 2004, 37, 724. [3] F. Millange, C. Serre, G. Férey, Chem. Commun. 2002, 822. [4] C. Serre, F. Millange, C. Thouvenot, M. Nogues, G. Marsolier, D. Louer, G. Férey, J. Am. Chem. Soc. 2002, 124, [5] C. Frontera, J. Rodriguez-Carvajal, Physica B 2003, 335, 219. [6] G. Kresse, J. Hafner, Phys. Rev. B 1993, 47, 558. [7] G. Kresse, D. Joubert, Phys. Rev. B 1999, 59, [8] J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 1996, 77, 3865.