van der Waals Interactions in Layered Lithium Cobalt Oxides

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• 作者：Muratahan Aykol ; Soo Kim ; C. Wolverton
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：119
• 期：33
• 页码：19053-19058
• 全文大小：409K
• ISSN：1932-7455

文摘

The role of van der Waals (vdW) interactions in density functional theory (DFT) + U calculations of the layered lithium-ion battery cathode Li_xCoO₂ (x = 0鈥?) is investigated using (i) dispersion corrections in the Perdew鈥揃urke鈥揈rnzerhof (PBE) generalized gradient approximation functional, (ii) vdW density functionals, and (iii) the Bayesian error estimation functional with vdW correlation. We find that combining vdW corrections or functionals with DFT+U can yield lithiation voltages, relative stabilities, and structural properties that are in much better agreement with experiments for the phases O1-CoO₂, O3-CoO₂, layered-Li_0.5CoO₂, spinel-Li_0.5CoO₂, and LiCoO₂ than using DFT+U or vdW-inclusive methods alone or using the hybrid Heyd鈥揝cuseria鈥揈rnzerhof functional. Contributions of vdW interactions to the lithiation voltages are estimated to have a similar magnitude with that of applying a typical U in the range 2鈥? eV for cobalt, each accounting for 5鈥?0% of calculated voltages relative to PBE. Relative stabilities of O1 and O3-CoO₂ as well as layered- and spinel-Li_0.5CoO₂ are correctly predicted with vdW-inclusive methods combined with the +U correction.