Stabilizing a High-Voltage Lithium-Rich Layered Oxide Cathode with a Novel Electrolyte Additive

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• High-voltage lithium-rich oxide cathodes are crucial for advanced energy storage.
• Their practical application is hindered by poor cycling stability and degradation issues.

Purpose of the Study:

• To introduce and evaluate a novel electrolyte additive for stabilizing high-voltage lithium-rich oxide cathodes.
• To elucidate the mechanism by which the additive enhances cathode performance.

Main Methods:

• Electrochemical charge/discharge tests in Li-based half cells and graphite-based full cells.
• Physical characterization techniques to analyze electrode surfaces and interfaces.
• Theoretical calculations to understand additive-electrolyte interactions.

Main Results:

• Trace amounts of bis(trimethylsilyl)carbodiimide dramatically improved cycling stability.
• Capacity retention after 200 cycles at 4.8 V increased from 40% to 72% (half cells) and 49% to 77% (full cells).
• The additive formed a protective film and scavenged detrimental species like hydrogen fluoride.

Conclusions:

• Bis(trimethylsilyl)carbodiimide is a highly effective electrolyte additive for high-voltage lithium-rich oxide cathodes.
• The additive enhances battery longevity by stabilizing the cathode-electrolyte interface and mitigating degradation pathways.
• This finding offers a promising strategy for developing more durable and high-performance lithium-ion batteries.