Fluorination from Surface to Bulk Stabilizing High Nickel Cathode Materials with Outstanding Electrochemical...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High nickel layered oxides are promising for high energy density batteries.
• Commercialization is hindered by capacity fading and voltage decay due to surface reactivity and phase transitions.

Purpose of the Study:

• To develop a fluorination strategy to address stability issues in high nickel layered oxide cathodes.
• To enhance electrochemical performance under high-rate and high-voltage conditions.

Main Methods:

• Introducing fluorine (F) atoms into the oxygen layer of layered oxides.
• Creating a fluorine-aggregated interface.
• Analyzing the effects of F substitution on ionic framework stability and Li+ diffusion.

Main Results:

• Fluorine substitution for oxygen stabilizes the layered structure via TM-F bonding, reducing lattice strain.
• A stable cathode-electrolyte interface (CEI) is formed, mitigating oxygen vacancy formation, HF attacks, and metal dissolution.
• The fluorinated cathode achieved a reversible capacity of 192.9 mAh g⁻¹ at 10 C (2.7-4.5 V).

Conclusions:

• Fluorination is an effective strategy for stabilizing high nickel layered oxide cathodes.
• This approach enhances Li+ dynamics and interfacial stability for high-rate, high-voltage battery applications.
• The study provides design concepts for advanced cathode materials.