Spinel-Layered Intergrowth Composite Cathodes for Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Layered manganese oxides face capacity degradation and sluggish ion diffusion in sodium-ion batteries due to irreversible phase transitions.
• Developing stable and efficient cathode materials is critical for advancing sodium-ion battery technology.

Purpose of the Study:

• To design and investigate a novel spinel-layered manganese-based composite cathode with an intergrowth structure for sodium-ion batteries.
• To enhance electrochemical performance by stabilizing the structure and improving ion diffusion kinetics.

Main Methods:

• Synthesis of a spinel-layered manganese-based composite via spinel-to-layered transformation.
• Structure characterization using multiple analysis techniques.
• Electrochemical performance evaluation, including capacity, cycling stability, and rate capability.
• Mechanism elucidation using ex situ X-ray diffraction and X-ray photoelectron spectroscopy.

Main Results:

• A unique spinel-layered intergrowth structure was successfully synthesized and confirmed.
• The composite cathode achieved a high reversible capacity of 180.9 mAh g⁻¹.
• Excellent cycling stability and superior rate capability (55.7 mAh g⁻¹ at 12 C) were demonstrated.
• The reaction mechanism revealed voltage-dependent Na⁺ accommodation by both layered and spinel components.

Conclusions:

• The spinel-layered intergrowth structure effectively mitigates capacity degradation and enhances ion diffusion kinetics in manganese oxide cathodes.
• This composite material presents a promising cathode for high-performance sodium-ion batteries.
• The findings offer a new strategy for designing advanced cathode materials for next-generation energy storage.