Insights into MoS2-coated LiVPO4F for lithium ion batteries: A first-principles investigation

• LiVPO4F (010) surface exposing Li and O atoms is the lowest energy surface.
• New surface states reduce the band gap of LiVPO4F surface.
• MoS2 coating dramatically increases the stability of LiVPO4F surface.
• MoS2 coating enhances the performance of electron transmission.

The structure, stability and electron conductivity of LiVPO4F covered by MoS2 were investigated by a first-principles method based on density functional theory. Calculations show that the low-index LiVPO4F (010) surface exposing Li and O atoms is the lowest energy surface. The formation of a new surface-state near the Fermi level reduces the band gap of the LiVPO4F surface compared to that of the bulk. For clean LiVPO4F surfaces, the quantum state near the Fermi level is dominated by the V-3d orbital. In addition, PDOS of V atoms shows significant differences in different atomic layers. MoS2 coating dramatically increases the stability of the LiVPO4F surface by forming strong covalent bonds with this surface. Additionally, it also enhances the electronic conductivity by reducing the band gap and generating new electronic states at the Fermi level. These theoretical results are consistent with experimental data.