Ab Initio Atomistic Thermodynamics Study of the (001) Surface of LiCoO2 in a Water Environment and Implications for Reactivity under Ambient Conditions

作者：Huang Xu; Bennett Joseph W; Hang Mimi N; Laudadio Elizabeth D; Hamers Robert J; Mason Sara E^*

来源：Journal of Physical Chemistry C, 2017, 121(9): 5069-5080.

DOI：10.1021/acs.jpcc.6b12163

We use GGA + U methodology to model the bulk and surface structure of varying stoichiometries of the (001) surface of LiCoO2. The DFT energies obtained for these surface-slab models are used for two thermodynamic analyses to assess the relative stabilities of different surface configurations, including hydroxylation. In the first approach, surface free energies are calculated within a thermodynamic framework, and the second approach is a surface-solvent ion exchange model. We find that, for both models, the-CoO-H-1/2 surface is the most stable structure near the O-rich limit, which corresponds to ambient conditions. We find that surfaces terminated with Li are higher in energy, and we go on to show that H and Li behave differently on the (001) LiCoO2 surface. The optimized geometries show that terminal Li and H occupy nonequivalent surface sites. In terms structure, Li and H terminations exhibit distinct bandgap characters, and there is also a distinctive surface. We go on to probe how the variable Li and H terminations affect reactivity, as probed through phosphate studies.

• 出版日期2017-3-9