High Performance 4.6 V LiCoO₂ Cathode Materials Enabled by Surface Lattice Modulation.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Increasing lithium cobalt oxide (LCO) cathode voltage to 4.6 V boosts reversible capacity.
• Higher voltages introduce significant stability challenges for LCO cathodes.

Purpose of the Study:

• To enhance the stability of high-voltage LCO cathodes while maintaining high capacity.
• To develop a precise surface modification technique for LCO.

Main Methods:

• Decomposition-induced reconstruction (DIR) process.
• Coating LCO with a conformal Y(OH)CO3 nanoshell.
• Controlled sintering to induce hydrocarbonate decomposition and surface lattice transformation.

Main Results:

• The DIR process created a stable, rock-salt-like surface structure on the LCO cathode.
• The modified LCO cathode achieved a capacity of 215.8 mAh g⁻¹ at 0.1 C with 93.0% retention after 100 cycles at 4.6 V.
• Demonstrated superior long-term cycling stability (85.5% vs. 13.6% after 500 cycles at 1 C) and performance under harsh conditions.

Conclusions:

• Surface chemistry engineering is crucial for overcoming stability issues in high-voltage LCO cathodes.
• The DIR method offers precise control for developing robust, high-energy-density lithium-ion battery cathodes.
• This approach provides valuable insights for future battery material development.