Specific Adsorption-Oxidation Strategy in Cathode Inner Helmholtz Plane Enabling 4.6 V Practical Lithium-Ion Full...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• High cutoff voltages maximize capacity in layered-oxide cathodes (LiTMO2).
• High voltage/temperature causes carbonate dehydrogenation-oxidation, leading to weak cathode electrolyte interphase (CEI) and structural collapse.
• Developing stable CEI is crucial for high-voltage battery performance.

Purpose of the Study:

• Investigate a specific adsorption-oxidation (Ad-O) mechanism for CEI formation.
• Develop tailored additives to control CEI generation in the cathode inner Helmholtz plane (C-IHP).
• Enhance the stability and performance of high-voltage layered-oxide cathodes.

Main Methods:

• Utilized molecular regulation within the C-IHP via tailored additives with electron-rich groups.
• Studied the adsorption-oxidation mechanism of additives on cathode active sites.
• Analyzed the resulting hierarchical CEI structure (inner LiF, outer B-F/-CN organic).

Main Results:

• Tailored additives masked cathode active sites, reducing weak CEI generation.
• A hierarchical CEI layer formed, protecting the cathode from electrolyte corrosion.
• LiNi0.8Co0.1Mn0.1O2/Graphite pouch cells achieved 270 Wh/kg at 4.6 V and 60 °C.
• Cells maintained performance over 450 cycles.

Conclusions:

• The specific Ad-O mechanism effectively regulates CEI formation for high-voltage cathodes.
• Synergistic strategy using tailored additives enhances cathode stability and electrochemical performance.
• Achieved significant energy density and cycle life for next-generation lithium-ion batteries.