Mo-Pre-Intercalated MnO₂ Cathode with Highly Stable Layered Structure and Expanded Interlayer Spacing for Aqueous...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Manganese-based oxides offer high voltage and low cost for aqueous rechargeable zinc-ion batteries (ZIBs).
• However, sluggish reaction kinetics and poor structural stability limit their practical application.
• δ-MnO₂, a promising cathode material, suffers from these limitations.

Purpose of the Study:

• To enhance the electrochemical performance of δ-MnO₂ for ZIBs.
• To address the challenges of sluggish kinetics and poor structural stability in manganese-based oxides.
• To investigate the role of molybdenum (Mo) pre-intercalation in improving δ-MnO₂ cathode performance.

Main Methods:

• A molybdenum (Mo) pre-intercalation strategy was employed for δ-MnO₂.
• The structural and electrochemical properties of the Mo-pre-intercalated δ-MnO₂ (Mo-MnO₂) were characterized.
• Ex situ experiments were used to reveal the energy storage mechanism.

Main Results:

• Mo dopants acted as pillars, expanding interlayer spacing and reinforcing the layered structure of δ-MnO₂.
• Mo pre-intercalation introduced oxygen defects, further enhancing reaction kinetics and capacity.
• The Mo-MnO₂ cathode achieved a high energy density of 451 Wh kg^-1, excellent rate capability, and retained 159 mAhg^-1 at 1.0 A g^-1 after 1000 cycles.

Conclusions:

• Molybdenum pre-intercalation is an effective strategy to boost the electrochemical performance of δ-MnO₂ for ZIBs.
• The enhanced kinetics, structural stability, and high capacity make Mo-MnO₂ a promising cathode material.
• This work provides valuable insights for designing high-performance manganese-based oxide cathodes for ZIBs.