Lithiation of a Silicon Oxide Cluster Adsorbed onto Graphene Oxide: Quantum-Chemical Simulation

The processes of adsorption of a silicon oxide cluster onto the surface of reduced graphene oxide (GO) have been considered. The calculations have been performed at the PBE/PAW, ωB97XD/6-31G( d , p ), and ωB97XD/6-31G( d , p )/6-311G( d , p )BSSE levels with inclusion of periodic conditions and in the cluster approximation. Upon the formation of GO, graphene sheets are distorted in the vicinity of bonding with oxygen. It is energetically favorable for the Si n O x cluster to be located on the concave side of the surface (opposite of adsorbed oxygen). This stabilizes the position of the clusters and prevents the “drift” of silicon oxide during lithiation. The lithiation involves oxygen and silicon atoms. The lithium conductivity will depend on the Li/O and Li/O c ratios, where O and O c are the numbers of oxygen atoms on the silicon oxide and graphene oxide surfaces, respectively. Lithium migration occurs through oxygen atoms bound to silicon in the case of a small ratio Li/O ≤ 1/2 and captures O c oxygen atoms covering graphene in the case of Li/O ≥ 1.