Rohrer Jochen, Kaghazchi Payam
Institut für Materialwissenschaft, Fachgebiet Materialmodellierung, Technische Universität Darmstadt, Jovanka-Bontschits-Str. 2, 64287 Darmstadt (Germany).
Chemphyschem. 2014 Dec 15;15(18):3950-4. doi: 10.1002/cphc.201402456. Epub 2014 Sep 22.
The interaction of ethylene carbonate (EC) with Si surfaces is studied by density functional theory. The results show a strong structure sensitivity in the adsorption of EC on Si surfaces. While the adsorbed EC molecule readily decomposes on the Li/Si(111) surface, it does not dissociate on the Li/Si(100) and Li/Si(110) surfaces. On Si(111), the O atom at the top of EC is detached from the EC molecule and binds to the Li adatom, forming Li-O molecules. The mechanism of EC decomposition is the transfer of 2.4 electrons from the surface to the EC molecule, as well as the formation of a covalent bond between the Li adatom and the EC molecule. This result shows that in lithium-ion batteries with Si anodes, dissociation of the solvent and formation of a solid electrolyte interphase layer start as soon as the Li atoms cover the anode surface.
采用密度泛函理论研究了碳酸亚乙酯（EC）与硅表面的相互作用。结果表明，EC在硅表面的吸附具有很强的结构敏感性。虽然吸附的EC分子在Li/Si(111)表面容易分解，但在Li/Si(100)和Li/Si(110)表面不会解离。在Si(111)上，EC顶部的O原子从EC分子上脱离并与Li吸附原子结合，形成Li-O分子。EC分解的机制是表面向EC分子转移2.4个电子，以及Li吸附原子与EC分子之间形成共价键。该结果表明，在具有硅阳极的锂离子电池中，一旦锂原子覆盖阳极表面，溶剂就会解离并形成固体电解质界面层。
