Insight into the Lithiation of SiO2 As a New Energy Storage Anode Material for Li-Ion Batteries
To better understand the lithiation behavior in SiO2 at the atomistic level we herein performed a series of reactive molecular dynamics simulation combining with the grand canonical montecarlo (GCMC) to demonstrate the lithiation behavior of SiO2. In addition, the Li transports throughout both crystalline and amorphous silica have been investigated. ReaxFF parameters are improved to account for the interaction of Li with Si and O atoms. We performed density functional theory calculations to examine the structural evolution, bonding mechanism, and voltage profile of lithiated c-SiO2 and a-SiO2. Both ReaxFF and DFT results indicate anisotropic long range Li-diffusion throughout the a-Quartz lattice. More specifically, Li should overcome 0.12 eV barrier heights when it transports along the c-axis of α-Quartz crystal, whereas the barrier of diffusion for Li moving perpendicular to the c-axis is calculated around 0.9 eV. Li transport throughout a-SiO2 bulk is also investigated and the results are compared with barriers obtained from DFT simulations.