Hierarchical Ternary MoO₂/MoS₂/Heteroatom‐Doped Carbon Hybrid Materials for High‐Performance Lithium‐Ion Storage

Abstract

The synthesis and electrochemical lithium‐ion storage behavior of hierarchical MoO2/MoS2/heteroatom‐doped carbon (MoO2/MoS2/HD‐C) ternary hybrid have been studied. This ternary hybrid is composed of ultrafine MoO2 nanowires and single/few‐layer MoS2 encapsulated by heteroatom‐doped carbon, constituting secondary cauliflower‐like microspheres. The synthesis is achieved through the synergistic interplay of a polymer and an ionic liquid as structure‐directing agents and carbon sources, using a solvothermal reaction followed by a simple thermal treatment. In this unique architecture, each component synergistically acts with a specific purpose. The HD‐C matrix with abundant defects and vacancies provides fast electronic conduction as well as interfacial storage, and buffers the volume changes during charging/discharging processes. The ultrasmall dimensions of both MoO2 nanowires and single/few‐layered MoS2 components enable rapid Li+ transport in all directions, which is of great benefit to the reversibility of “conversion” reactions. The hierarchical secondary structures assure the robust stability upon long‐term cycling. The ternary hybrid material exhibits enhanced Li+‐storage performance as well as reversible capacity, rate capability, and cycling stability. A high reversible specific capacity of 1147 mA h g−1 is delivered at 50 mA g−1 together with excellent cycling stability, and 841 mA h g−1 can be retained after 1000 cycles at 500 mA g−1.

Photocatalytic Behaviors of TiO2 Nanoblets Coated with MoS2 Nanosheets for Solar‐Driven Photocatalysis

“…According to the previous reports, the appearance of Mo 6+ indicates the reduction reaction has not completely finished or a small amount of Mo 4+ on the surface was oxidized in air . The peak at 226.5 eV is associated with S 2 s . The peak located at 163.5 eV and 162.3 eV can be assigned to S 2p 1/2 and S 2p 3/2 , as depicted in Figure b .…”

“…And the two weak peaks with the binding energies of 236.2 eV and 232.4 eV correspond to Mo 6+ 3d 3/2 and Mo 6+ 3d 5/2 , respectively . According to the previous reports, the appearance of Mo 6+ indicates the reduction reaction has not completely finished or a small amount of Mo 4+ on the surface was oxidized in air . The peak at 226.5 eV is associated with S 2 s .…”

“…The two strong peaks with the binding energies of 232.9 eV and 229.5 eV correspond to Mo 4+ 3d 3/2 and Mo 4+ 3d 5/2 , respectively . And the two weak peaks with the binding energies of 236.2 eV and 232.4 eV correspond to Mo 6+ 3d 3/2 and Mo 6+ 3d 5/2 , respectively . According to the previous reports, the appearance of Mo 6+ indicates the reduction reaction has not completely finished or a small amount of Mo 4+ on the surface was oxidized in air .…”

“…The peak at 226.5 eV is associated with S 2 s . The peak located at 163.5 eV and 162.3 eV can be assigned to S 2p 1/2 and S 2p 3/2 , as depicted in Figure b . As shown in Figure c, the peaks at 465.2 eV and 459.5 eV are associated with Ti 2p 1/2 and Ti 2p 3/2 , respectively.…”

“…As illustrated in Figure a, Mo 3d spectrum contains five peaks. The two strong peaks with the binding energies of 232.9 eV and 229.5 eV correspond to Mo 4+ 3d 3/2 and Mo 4+ 3d 5/2 , respectively . And the two weak peaks with the binding energies of 236.2 eV and 232.4 eV correspond to Mo 6+ 3d 3/2 and Mo 6+ 3d 5/2 , respectively .…”