期刊
JOURNAL OF MATERIALS CHEMISTRY A
卷 1, 期 47, 页码 14879-14887出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c3ta13559d
关键词
-
资金
- EPSRC [EP/L000202]
- Office of Science and Technology through EPSRC's High End Computing Programme
- South African Research Chair Initiative of the Department of Science and Technology
- National Research Foundation in South Africa
- EPSRC [EP/F067496/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/F067496/1] Funding Source: researchfish
The adsorption and co-adsorption of lithium and oxygen at the surface of rutile-like manganese dioxide (beta-MnO2), which are important in the context of Li-air batteries, are investigated using density functional theory. In the absence of lithium, the most stable surface of beta-MnO2, the (110), adsorbs oxygen in the form of peroxo groups bridging between two manganese cations. Conversely, in the absence of excess oxygen, lithium atoms adsorb on the (110) surface at two different sites, which are both tri-coordinated to surface oxygen anions, and the adsorption always involves the transfer of one electron from the adatom to one of the five-coordinated manganese cations at the surface, creating (formally) Li+ and Mn3+ species. The co-adsorption of lithium and oxygen leads to the formation of a surface oxide, involving the dissociation of the O-2 molecule, where the O adatoms saturate the coordination of surface Mn cations and also bind to the Li adatoms. This process is energetically more favourable than the formation of gas-phase lithium peroxide (Li2O2) monomers, but less favourable than the formation of Li2O2 bulk. These results suggest that the presence of beta-MnO2 in the cathode of a nonaqueous Li-O-2 battery lowers the energy for the initial reduction of oxygen during cell discharge.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据