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Atomistic Modeling of the Charge Process in Lithium/Air Batteries
被引:10
作者:
Dabrowski, Tatjana
[1
,2
,3
]
Ciacchi, Lucio Colombi
[1
,2
,4
]
机构:
[1] Univ Bremen, BCCMS, Hybrid Mat Interfaces Grp, Fac Prod Engn, D-28359 Bremen, Germany
[2] Univ Bremen, Ctr Environm Res & Sustainable Technol UFT, D-28359 Bremen, Germany
[3] Fraunhofer Inst Mfg Technol & Adv Mat IFAM, D-26129 Oldenburg, Germany
[4] Univ Bremen, MAPEX Ctr Mat & Proc, D-28359 Bremen, Germany
关键词:
LI-AIR CELLS;
DIMETHYL-SULFOXIDE;
MOLECULAR-DYNAMICS;
OXYGEN BATTERY;
LI2O2;
PEROXIDE;
KINETICS;
ASSOCIATION;
REDUCTION;
SOLVATION;
D O I:
10.1021/acs.jpcc.5b09002
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
We present a combined classical and density functional theory (DFT) based Molecular Dynamics (MD) study of the mechanisms underlying the oxygen evolution reactions during the charging of lithium/air batteries. As models for the Li2O2 material at the cathode we employ small amorphous clusters with a 2:2 Li:O stoichiometry, whose energetically most stable atomic configurations comprise both O atoms and O-O pairs with mixed peroxide/superoxide character, as revealed by their bond lengths, charges, spin moments, and densities of states. The oxidation of Li8O8 clusters is studied in unbiased DFT-based MD simulations upon removal of either one or two electrons, either in vacuo or immersed in dimethyl sulfoxide solvent molecules with a structure previously optimized by means of classical MD. Whereas removal of one electron leads only to an enhancement of the superoxide character of O-O bonds, removal of two electrons leads to the spontaneous dissolution of either an O-2 or a LiO2+ molecule. These results are interpreted in terms of a two-stage process in which a peroxide-to-superoxide transition can take place in amorphous Li2O2 phases at low oxidation potentials, later followed by the dissolution of dioxygen molecules and Li+ ions at higher potentials.
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页码:25807 / 25817
页数:11
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