In Situ-Constructed Multifunctional Interface for High-Voltage 4.6 V LiCoO₂

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium cobalt oxide (LCO) dominates lithium-ion battery cathodes due to high energy density.
• Increasing charge voltage to 4.6 V for higher energy density causes interface instability, cobalt dissolution, and oxygen release.
• Developing stable cathode materials is crucial for advanced energy storage.

Purpose of the Study:

• To enhance the stability and performance of LCO cathodes at higher charge voltages.
• To investigate the effect of Li$_{1.8}$Sc$_{0.8}$Ti$_{1.2}$(PO$_{4}$)$_{3}$ (LSTP) coating on LCO.
• To understand the interface modification and ion transport mechanisms.

Main Methods:

• Coating LCO with LSTP to form LCO@LSTP.
• In situ interface construction via LSTP decomposition.
• Doping LCO with Ti and Sc elements.
• Electrochemical testing (capacity, cycling stability).
• Surface analysis using Kelvin Probe Force Microscopy (KPFM) and Density Functional Theory (DFT).

Main Results:

• LSTP coating and decomposition create a stable, spinel-structured interface on LCO.
• Doping with Ti and Sc improves interface stability and Li+ transport.
• LCO@LSTP exhibits a specific capacity of 202.3 mAh g-1 at 0.5C (3.0-4.6 V).
• Capacity retention improved significantly to 89.0% after 100 cycles compared to bare LCO (50.9%).

Conclusions:

• LSTP coating effectively stabilizes the LCO cathode interface at high voltages.
• The modified interface enhances Li+ conductivity and electrochemical performance.
• This strategy offers a promising pathway for developing high-energy-density lithium-ion batteries.