Integrating a Ferroelectric Interface with a Well-Tuned Electronic Structure in Lithium-Rich Layered Oxide Cathodes...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Li-rich layered oxides (LLOs) are promising for high-energy-density batteries.
• Challenges include irreversible Li/O loss, structural degradation, and interfacial reactions.
• These issues limit large-scale applications of LLOs.

Purpose of the Study:

• To improve the electrochemical performance and stability of LLOs.
• To address challenges like structural degradation and interfacial side reactions.
• To enable high-voltage operation for next-generation batteries.

Main Methods:

• La/Al codoping to tune electronic structure.
• Bi_0.5Na_0.5TiO₃ (BNT) coating to create a ferroelectric interface.
• Electrochemical characterization and analysis of structural stability.

Main Results:

• Synergistic effect of ferroelectric interface and tuned electronic structure.
• Enhanced Li⁺ diffusion and suppressed O migration.
• Suppressed lattice volume changes and reduced interfacial side reactions up to 4.9 V.
• Improved initial capacities and cycling stability: 224.4 mAh g^-1 (78.57% retention after 500 cycles at 4.65 V) and 231.7 mAh g^-1 (85.76% retention after 200 cycles at 4.9 V).

Conclusions:

• The integrated strategy effectively enhances LLO performance.
• The ferroelectric interface and electronic structure modification are key to improved stability and high-voltage cycling.
• This approach offers a pathway for developing advanced cathode materials for high-energy batteries.