Surface Reconstruction and Lattice Oxygen Modulation of 4.6 V LiCoO₂ Cathode for Enhanced Fast-Charging Durability

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Increasing energy density in lithium cobalt oxide (LiCoO2) batteries often involves higher charging cutoff voltages, leading to structural instability and performance degradation.
• Developing strategies to mitigate these adverse effects is crucial for advancing high-voltage battery technology.

Purpose of the Study:

• To investigate the synergistic effects of surface reconstruction and lattice oxygen modulation via Barium (Ba)-doping in LiCoO2.
• To enhance the structural stability and electrochemical performance of LiCoO2 for high-voltage applications.

Main Methods:

• Synergistic strategy involving Barium (Ba)-doping for surface reconstruction and lattice oxygen modulation.
• Electrochemical cycling and characterization of pristine and Ba-doped LiCoO2 at high voltages (up to 4.6 V).
• Analysis of structural changes, including phase transitions and lithium-ion diffusion pathways.

Main Results:

• Ba-doped LiCoO2 demonstrated fast-charging durability at 4.6 V with significantly improved capacity retention (69.4% after 200 cycles at 1 C) compared to pristine LiCoO2 (16.8%).
• Ba-doping facilitated lithium-ion transport by introducing lattice oxygen vacancies and tailoring the surface layer.
• A stable spinel phase with 3D lithium-ion diffusion channels was observed in Ba-doped LiCoO2, suppressing lattice strain, degradation, and gas release.

Conclusions:

• Barium doping is an effective strategy for lattice engineering in LiCoO2, enhancing structural stability and electrochemical performance at high voltages.
• This approach mitigates degradation issues associated with high cutoff voltages, paving the way for next-generation high-energy-density batteries.
• The findings highlight the potential of controlled doping and lattice modulation for developing robust and efficient battery materials.