Crystal water intercalated interlayer expanded MoS₂ nanosheets as a cathode for efficient zinc-ion storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc-ion batteries (ZIBs) offer safety and cost benefits but require improved cathode materials.
• Molybdenum disulfide (MoS₂) is a promising 2D material for ZIB cathodes, yet faces challenges like limited interlayer spacing and poor conductivity.

Purpose of the Study:

• To develop an efficient cathode material for ZIBs by modifying MoS₂.
• To investigate the impact of crystal water intercalation on MoS₂ properties and electrochemical performance.

Main Methods:

• A facile hydrothermal method was used to synthesize crystal water-intercalated MoS₂ nanosheets (MoS₂·nH₂O).
• Morphological characterization (average thickness 15.2 nm) and analysis of interlayer spacing (0.79 nm), 1T phase content (49.7%), and defect levels were performed.

Main Results:

• MoS₂·nH₂O demonstrated a high discharge capacity of 197 mA h g^-1 at 0.1 A g^-1 in a 2 M ZnSO₄ electrolyte.
• The material exhibited modest cyclic stability with 55% capacity retention after 1000 cycles.
• Charge storage kinetics revealed diffusion-controlled electrochemical reactions with diffusion coefficients ranging from 10^-10 to 10^-13 cm² s^-1.

Conclusions:

• Crystal water intercalation is a simple and effective strategy to enhance MoS₂ performance for ZIBs.
• The modified MoS₂ nanosheets show potential for efficient zinc-ion storage.
• This approach could facilitate the commercialization of ZIBs for grid-scale energy storage.