Achieving a Deeply Desodiated Stabilized Cathode Material by the High Entropy Strategy for Sodium-ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Manganese-based layered oxides are promising cathode materials for sodium-ion batteries (SIBs) due to their low toxicity and high capacity.
• Challenges include sluggish sodium-ion (Na+) migration and poor structural stability caused by Jahn-Teller distortion and phase transitions.

Purpose of the Study:

• To enhance the high-voltage capacity and cycling stability of manganese-based layered oxides using a high-entropy strategy.
• To develop advanced cathode materials for efficient and stable sodium-ion batteries.

Main Methods:

• A high-entropy strategy was employed to synthesize P2-Na0.67Mn0.6Cu0.08Ni0.09Fe0.18Ti0.05O2.
• Electrochemical performance, including deep sodiation and cycling stability, was evaluated.
• Crystal structure stability was analyzed through lattice parameter variations.

Main Results:

• The designed P2-Na0.67Mn0.6Cu0.08Ni0.09Fe0.18Ti0.05O2 cathode delivered a high charging capacity of 158.1 mAh g-1 (0.61 Na).
• A high initial Coulombic efficiency of 98.2% was achieved, indicating efficient charge compensation via synergistic cationic and anionic redox reactions.
• The crystal structure demonstrated enhanced stability with minimal lattice parameter variations during cycling.

Conclusions:

• The high-entropy strategy effectively stabilizes the crystal structure and improves electrochemical performance of manganese-based layered oxides.
• This research contributes to the development of low-cost, high-energy-density cathode materials for next-generation sodium-ion batteries.