Enabling High-Voltage and Long Lifespan Sodium Batteries via Single-Crystal Layer-Structured Oxide Cathode Material

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Manganese-based layered oxides are promising for sodium batteries due to energy density and feasibility.
• Grain boundaries and side reactions limit performance, especially at high voltages.

Purpose of the Study:

• To design and synthesize a large-sized single-crystal cathode material for high-voltage, long-lifespan sodium batteries.
• To overcome limitations of polycrystalline materials in sodium-ion energy storage.

Main Methods:

• Synthesis of O3-typed Na[Ni_0.3Mn_0.5Cu_0.1Ti_0.1]O₂ as large single crystals.
• Electrochemical characterization of the material in sodium battery configurations.

Main Results:

• Single-crystal structure facilitates faster Na+ diffusion and higher electronic conductivity.
• The (003) plane enhances stability against side reactions and structural degradation.
• Achieved specific capacity of 160.1 mAh g^-1 (0.1 C) and 141.1 mAh g^-1 in a full cell.
• Demonstrated excellent cycling stability with 97.3% retention after 100 cycles at 2 C.

Conclusions:

• Single-crystal design effectively suppresses detrimental effects in manganese-based cathodes.
• The developed material shows significant potential for advanced high-performance sodium batteries.