Tri-Sites Element Doping with Eu─Al─F Toward Stable High-Voltage LiCoO₂.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium cobalt oxide (LCO) is a primary cathode material for lithium-ion batteries.
• Current LCO performance limitations hinder the development of high-energy-density batteries for advanced electronics.
• Increasing charging voltage improves LCO capacity but leads to degradation and capacity fade.

Purpose of the Study:

• To enhance the high-voltage performance and cyclic stability of LCO cathodes.
• To investigate a tri-sites multi-element doping strategy using Europium (Eu), Aluminum (Al), and Fluorine (F).

Main Methods:

• Developed a tri-sites co-doping strategy with Eu, Al, and F elements for LCO.
• Tested the modified LCO cathode at a high cut-off voltage of 4.55 V.
• Analyzed structural and electrochemical properties to evaluate performance and stability.

Main Results:

• The Eu-Al-F co-doped LCO cathode achieved an initial discharge capacity of 205 mAh g⁻¹ at 4.55 V.
• The modified cathode maintained over 80% capacity retention after 250 cycles.
• The doping strategy effectively suppressed irreversible phase transitions, oxygen loss, and internal stress.

Conclusions:

• The tri-sites co-doping strategy significantly improves the cyclic stability of high-voltage LCO.
• This method offers a promising pathway for developing advanced lithium-ion batteries with higher energy density and durability.
• The study provides insights into mitigating degradation mechanisms in high-voltage cathode materials.