Hierarchical Microtubes Constructed by MoS₂ Nanosheets with Enhanced Sodium Storage Performance

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are promising for large-scale energy storage.
• Developing suitable electrode materials for SIBs is challenging due to the large Na⁺ ion radius.

Purpose of the Study:

• To synthesize hierarchical tubular molybdenum disulfide (MoS₂) for SIBs.
• To investigate the effect of tetramethylammonium bromide (TMAB) on MoS₂ structure formation.
• To evaluate the electrochemical performance of the synthesized MoS₂ in SIBs.

Main Methods:

• Facial hydrothermal synthesis assisted by tetramethylammonium bromide (TMAB).
• Electrochemical characterization including cycling tests and rate capability.
• In situ X-ray diffraction (XRD) to study reaction mechanisms.

Main Results:

• Hierarchical tubular MoS₂ structures were successfully synthesized, requiring sufficient TMA⁺ ions.
• The MoS₂ electrode exhibited a high specific capacity (652.5 mAh/g at 100 mA/g) and excellent cycling stability (94.2% retention after 100 cycles at 1000 mA/g).
• In situ XRD revealed reversible Na⁺ intercalation/deintercalation and a conversion-type reaction.

Conclusions:

• The tubular hierarchical structure of MoS₂, with loosely stacked nanosheets, facilitates ion transport and mitigates volume changes, leading to enhanced electrochemical performance.
• The synthesis strategy is adaptable for creating other hierarchical metal oxides and sulfides for diverse applications.