Conductive binary Li borate glass coating for improved Ni-rich positive electrode in sulfide-based all-solid-state Li...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Ni-rich layered oxide cathodes are crucial for high-energy all-solid-state lithium batteries.
• Improving their electrochemical performance and stability, especially in sulfide electrolytes, remains a key challenge.
• Cost-effective and high-performance electrode solutions are needed for practical applications.

Purpose of the Study:

• To develop a cost-effective coating strategy for Ni-rich layered oxide positive electrodes.
• To enhance the electrochemical performance and long-term stability of these electrodes in sulfide-based all-solid-state Li batteries.
• To investigate the mechanism by which the coating improves battery performance.

Main Methods:

• A thin (~3 nm) conductive binary Li borate glass (0.5Li2O·0.5B2O3) coating was applied to single-crystal LiNi0.8Co0.1Mn0.1O2.
• A simple dry process followed by heating was employed for the coating application.
• Electrochemical performance was evaluated using coin cells and pouch cells, complemented by various characterization techniques.

Main Results:

• The coated electrode delivered a specific capacity of 209 mAh g⁻¹ at 20 mA g⁻¹ with 79.7% initial Coulombic efficiency.
• It retained 87.8% capacity after 1000 cycles at 200 mA g⁻¹ and achieved an areal capacity of 14.6 mAh cm⁻².
• Pouch cells demonstrated a specific energy of 383 Wh kg⁻¹ and sustained 300 cycles at 66.67 mA g⁻¹.

Conclusions:

• The conductive Li borate glass coating effectively enhances Li-ion transport and stabilizes the positive electrode lattice.
• The coating strengthens the interface between the positive electrode and the sulfide electrolyte, improving overall battery stability.
• This approach enables high-voltage positive electrodes with high stability and specific energy for all-solid-state batteries.