  Silicon suboxide is currently considered as a unique candidate for lithium
ion batteries anode materials due to its considerable capacity. However, no
adequate information exist about the role of oxygen content on its performance.
To this aim, we used density functional theory to create silicon suboxide
matrices of various Si:O ratios and investigated the role of oxygen content on
the structural, dynamic, electronic properties and lithiation behavior of the
matrices. Our study demonstrates that the O atoms interact strongly with the
inserted Li atoms resulting in a disintegration of the host matrix. We found
that higher concentration of oxygen atoms in the mixture reduces its relative
expansion upon lithiation, which is a desirable quality for anode materials. It
helps in preventing crack formation and pulverization due to large fluctuations
in volume. Our study also demonstrate that a higher oxygen content increases
the lithium storage capacity of the anode. However, it can also cause the
formation of stable complexes like lithium silicates that might result into
reversible capacity loss as indicated by the voltage-composition curves. The
study provides valuable insights into the role of oxygen in moderating the
interaction of lithium in silicon suboxide mixture in microscopic details.
