摘要
We report on first-principles studies of lithium-intercalation-induced structural phase transitions in molybdenum disulphide (MoS2 ), a promising material for energy storage in lithium ion batteries. It is demonstrated that the inversion-symmetry-related Mo-S p-d covalence interaction and the anisotropy of d-band hybridization are the critical factors influencing the structural phase transitions upon Li ion intercalation. Li ion intercalation in 2H-MoS2 leads to two competing effects, i.e. the 2H-to-1T transition due to the weakening of Mo-S p-d interaction and the D 6h crystal field, and the charge-density-wave transition due to the Peierls instability in Li-intercalated 2H phase. The stabilization of charge density wave in Li-intercalated MoS2 originates from the enhanced electron correlation due to nearest-neighbor Mo-Mo d-d covalence interaction, conforming to the extended Hubbard model. The magnitude of charge density wave is affected by Mo-S p-d covalence interaction and the anisotropy of d-band hybridization. In 1T phase of Li-intercalated MoS2 , the strong anisotropy of d-band hybridization contributes to the strong Fermi surface nesting while the d-band nonbonding with S-p facilities effective electron injection.
We report on first-principles studies of lithium-intercalation-induced structural phase transitions in molybdenum disulphide (MoS2), a promising material for energy storage in lithium ion batteries. It is demonstrated that the inversion-symmetry-related Mo-S p-d covalence interaction and the anisotropy of d-band hybridization are the critical factors influencing the structural phase transitions upon Li ion intercalation. Li ion intercalation in 2H-MoS2 leads to two competing effects, i.e. the 2H-to-lT transition due to the weakening of Mo-S p-d interaction and the D6h crystal field, and the charge-density-wave transition due to the Peierls instability in Li-intercalated 2H phase. The stabilization of charge density wave in Li-intercalated MoS2 originates from the en- hanced electron correlation due to nearest-neighbor Mo-Mo d-d covalence interaction, conforming to the extended Hubbard mod- el. The magnitude of charge density wave is affected by Mo-S p-d covalence interaction and the anisotropy of d-band hybridiza- tion. In 1T phase of Li-intercalated MoS2, the strong anisotropy of d-band hybridization contributes to the strong Fermi surface nesting while the d-band nonbonding with S-p facilities effective electron injection.
基金
supported by the Ningbo Key Innovation Team and the Ningbo Natural Science Foundation (2011B82005, 2012A610098)
the Natural Science Foundation of Zhejiang Province (LQ12A04004)
the National Natural Science Foundation of China (11174301)
the National Basic Research Program of China (2012CB722700, SS2013AA050901)
X.Chen appreciates supports by the Postdoctoral Foundation of China(2012M510156)