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MM: Fachverband Metall- und Materialphysik
MM 9: Functional Materials - Battery Materials II
MM 9.2: Vortrag
Montag, 11. März 2013, 12:00–12:15, H26
Comparative computational study of Si, Ge, and Sn as anode materials for Mg batteries — •Sergei Manzhos1, Oleksandr Malyi2, and Teck L. Tan2 — 1Department of Mechanical Engineering, National University of Singapore, Blk EA #07-08, Singapore 117576 — 2Institute of High Performance Computing, A*STAR, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632
Magnesium batteries are emerging as a viable high energy density alternative to Li batteries that also circumvent potential Li supply risks. Most research has focused on the design of cathode materials for Mg batteries. Mg metal, while being safer than metallic Li, results in poor reversibility. The rechargeability and voltage could be improved by using an insertion anode, but theoretical studies of high-capacity Mg insertion anodes are lacking. We present ab initio calculations of the behavior of Mg atoms in bulk Ge, Si, Sn and their Mg alloys and evaluate their potential as insertion type anode materials. We show that despite the fact that Si and Ge could provide the highest specific capacities (3817 mAh g-1 and 1476 mAh/g, respectively) for Mg storage, they result in significant lattice expansions and slow Mg diffusion. Sn appears as a more attractive anode material with the barrier to diffusion as low as 0.32 eV and the smallest expansion among the three materials.