Integrated Structural Modulation Inducing Fast Charge Transfer in Aqueous Zinc-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer safe and cost-effective energy storage.
• Manganese oxides are promising cathode materials for AZIBs but suffer from structural degradation during cycling.
• Structural instability limits the reversible capacity and cycle life of MnO₂-based cathodes.

Purpose of the Study:

• To develop an advanced α-MnO₂@SnO₂ nanocomposite cathode material for AZIBs.
• To enhance the structural stability and electrochemical performance of MnO₂-based cathodes.
• To investigate the synergistic effects of lattice disorder and improved conductivity in the nanocomposite.

Main Methods:

• Facile hydrothermal synthesis of the α-MnO₂@SnO₂ nanocomposite.
• Electrochemical characterization, including cycling performance and rate capability tests.
• Ex situ experiments and density functional theory (DFT) calculations to analyze structural and electronic properties.

Main Results:

• The α-MnO₂@SnO₂ nanocomposite achieved a high reversible capacity of 347 mAh g^-1 at 100 mA g^-1 after 50 cycles.
• Excellent rate performance was demonstrated, with a capacity of 78 mAh g^-1 maintained at 5 A g^-1 after 1000 cycles.
• The nanocomposite exhibited enhanced structural stability and improved ion/electron exchange kinetics.

Conclusions:

• The developed α-MnO₂@SnO₂ nanocomposite effectively mitigates structural degradation in AZIB cathodes.
• Synergistic effects enhance electrochemical performance, leading to superior capacity and cycle life.
• The material shows great potential for advanced aqueous zinc-ion battery applications.