Synthesis And Hydrogen Sorption Properties Of Mg 2feh 6-mgh 2 Nanocomposite Prepared By Reactive Milling

The complex hydride Mg 2FeH 6 is an interesting material for hydrogen storage due to its high gravimetric hydrogen capacity as well as for having the highest known volumetric hydrogen density - 150 kg m -3. Several papers have recently reported its synthesis from the stoichiometric precursors 2Mg-Fe or 2MgH 2-Fe through sintering process and ball milling under argon or hydrogen atmosphere. However, regardless of processing conditions, a remaining iron always was identified by X-rays diffraction, which resulted in a lower hydrogen storage capacity. In the present paper, the Mg 2FeH 6-MgH 2 nanocomposite was successfully synthesized through high-energy ball milling from 3Mg-Fe mixture under hydrogen atmosphere at room temperature. After the ball milling, X-rays diffraction patterns showed that the iron was kept to a minimum, which was also confirmed by simultaneous thermal analysis of differential scanning calorimetry and thermogravimetry. The gravimetric density of the ball milled 3Mg-Fe is more than 5 wt.% of hydrogen. In the case of 2Mg-Fe, processed in the same condition, the measured hydrogen capacity was 3.5 wt.%. The hydrogen sorption kinetics analyses were performed in a Sievert's apparatus in temperatures ranging from 250 °C to 350 °C. Enhanced hydrogen sorption kinetics was observed for these 3Mg-Fe milled powders in comparison with the 2Mg-Fe ones. © 2012 Elsevier B.V. All rights reserved.536SUPPL.1S250S254Didisheim, J.-J., Zolliker, P., Yvon, K., Fischer, P., Schefer, J., Gubelmann, M., Wlliams, A.F., (1984) Inorg. Chem., 23, pp. 1953-1957Selvam, P., Yvon, K., (1991) Int. J. Hydrogen Energy, 16, pp. 615-617Huot, J., Hayakawa, H., Akiba, E., (1997) J. Alloys Compd., 248, pp. 164-167Huot, J., Boily, S., Akiba, E., Schulz, R., (1998) J. Alloys Compd., 280, pp. 306-309Sai Raman, S.S., Davidson, D.J., Bobet, J.-L., Srivastava, O.N., (2002) J. Alloys Compd., 333, pp. 282-290Gennari, F.C., Castro, F.J., Andrade Gamboa, J.J., (2002) J. Alloys Compd., 339, pp. 261-267Varin, R.A., Li, S., Calka, A., Wexler, D., (2004) J. Alloys Compd., 373, pp. 270-286Castro, F.J., Gennari, F.C., (2004) J. Alloys Compd., 375, pp. 292-296Li, S., Varin, R.A., Morozova, O., Khomenko, T., (2004) J. Alloys Compd., 384, pp. 231-248Varin, R.A., Li, S., Wronski, Z., Morozova, O., Khomenko, T., (2005) J. Alloys Compd., 390, pp. 282-296Varin, R.A., Li, S., Chiu, C., Guo, L., Morozova, O., Khomenko, T., Wronski, Z., (2005) J. Alloys Compd., 404-406, pp. 494-498Zhou, D.W., Li, S.L., Varin, R.A., Peng, P., Liu, J.S., Yang, F., (2006) Mater. Sci. Eng. A, 427, pp. 306-315Riktor, M.D., Deledda, S., Herrich, M., Gutfleisch, O., Fjellvag, H., Hauback, B.C., (2009) Mater. Sci. Eng. B, 158, pp. 19-25Leiva, D.R., Villela, A.C.S., Paiva-Santos, C.O., Fruchart, D., Miraglia, S., Ishikawa, T.T., Botta, W.J., (2011) Solid State Phenomena, 170, pp. 259-262Shang, C.X., Bououdina, M., Guo, Z.X., (2003) J. Alloys Compd., 356-357, pp. 626-629Herrich, M., Ismail, N., Lyubina, J., Handstein, A., Pratt, A., Gutfleisch, O., (2004) Mater. Sci. Eng. B, 108, pp. 28-32Puszkiel, J.A., Arneodolarochette, P., Gennari, F.C., (2009) J. Power Sources, 186, pp. 185-193Wang, Y., Cheng, F., Li, C., Tao, Z., Chen, J., (2010) J. Alloys Compd., 508, pp. 554-55