High-Entropy Layered Oxide Cathodes for Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing high-performance sodium-ion (Na-ion) battery cathodes is crucial for next-generation energy storage.
• Understanding the structural chemistry of these materials is a significant challenge.

Purpose of the Study:

• To introduce a novel high-entropy strategy for designing layered oxide cathodes for Na-ion batteries.
• To demonstrate the efficacy of this strategy through a specific material example.

Main Methods:

• Synthesis of a novel high-entropy layered oxide cathode material (O3-type NaNi_0.12 Cu_0.12 Mg_0.12 Fe_0.15 Co_0.15 Mn_0.1 Ti_0.1 Sn_0.1 Sb_0.04 O₂).
• Electrochemical testing to evaluate cycling stability and rate capability.
• Analysis of phase transition behavior during charge-discharge cycles.

Main Results:

• The demonstrated high-entropy cathode exhibits excellent cycling stability, retaining approximately 83% capacity after 500 cycles.
• Outstanding rate capability was observed, with about 80% capacity retention at a 5.0 C rate.
• A highly reversible O3-P3 phase transition was noted, with the O3-type region storing over 60% of the total capacity.

Conclusions:

• The high-entropy strategy offers a promising route for developing advanced Na-ion battery cathode materials.
• Multiple transition-metal components in high-entropy materials can effectively accommodate structural changes during ion intercalation/deintercalation.
• This work provides new insights into designing high-performance materials for sodium-ion batteries.