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Atomic Insight into the Lithium Storage and Diffusion Mechanism of SiO2/Al2O3 Electrodes of Lithium Ion Batteries: ReaxFF Reactive Force Field Modeling
journal contribution
posted on 2016-03-15, 00:00 authored by Alireza Ostadhossein, Sung-Yup Kim, Ekin D. Cubuk, Yue Qi, Adri C. T. van DuinAtomically deposited layers of SiO2 and Al2O3 have been recognized as promising
coating materials
to buffer the volumetric expansion and capacity retention upon the
chemo-mechanical cycling of the nanostructured silicon- (Si-) based
electrodes. Furthermore, silica (SiO2) is known as a promising
candidate for the anode of next-generation lithium ion batteries (LIBs)
due to its superior specific charge capacity and low discharge potential
similar to Si anodes. In order to describe Li-transport in mixed silica/alumina/silicon
systems we developed a ReaxFF potential for Li–Si–O–Al
interactions. Using this potential, a series of hybrid grand canonical
Monte Carlo (GCMC) and molecular dynamic (MD) simulations were carried
out to probe the lithiation behavior of silica structures. The Li
transport through both crystalline and amorphous silica was evaluated
using the newly optimized force field. The anisotropic diffusivity
of Li in crystalline silica cases is demonstrated. The ReaxFF diffusion
study also verifies the transferability of the new force field from
crystalline to amorphous phases. Our simulation results indicates
the capability of the developed force field to examine the energetics
and kinetics of lithiation as well as Li transportation within the
crystalline/amorphous silica and alumina phases and provide a fundamental
understanding on the lithiation reactions involved in the Si electrodes
covered by silica/alumina coating layers.