Promoting Surface Electric Conductivity for High-Rate LiCoO₂.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Cathode materials are crucial for Li-ion batteries, facilitating Li+ diffusion and electron transport.
• Research has primarily focused on Li+ diffusion, with less attention paid to electron transport properties.
• Improving electron transport is key to enhancing battery rate performance.

Purpose of the Study:

• To develop a strategy for enhancing cathode material rate performance by improving surface electric conductivity.
• To investigate the effect of surface modification on LiCoO2's electrochemical properties.
• To provide a new approach for designing high-rate cathode materials.

Main Methods:

• Coherent construction of a disordered rock-salt phase on the surface of LiCoO2.
• Electrochemical testing to evaluate rate capability and cycling performance.
• Surface characterization and computational simulations to confirm the strategy's universality.

Main Results:

• Surface electric conductivity of LiCoO2 was increased by over one magnitude.
• Enhanced Li+ extraction/insertion due to increased effective voltage (Veff).
• Superior rate capability (154 mAh g-1 at 10C) and excellent cycling performance (93% after 1000 cycles at 10C).

Conclusions:

• Promoting surface electric conductivity is an effective strategy to boost battery rate performance.
• The developed surface modification technique offers a new avenue for high-rate cathode material development.
• Tuning surface electron transport properties is critical for advanced Li-ion battery design.