Interfacial Regulation of a 4.5 V LiCoO₂-Based Battery via Advanced Slurry Additive Modification

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium cobalt oxide (LCO) is a key cathode material for consumer electronics due to its high energy density.
• Operating LCO beyond 4.5 V causes electrolyte decomposition, structural damage, and performance loss.

Purpose of the Study:

• To develop a protective layer that enhances the stability and performance of high-voltage LCO cathodes.
• To investigate the mechanism by which the protective layer improves LCO stability.

Main Methods:

• Functionalized polyester-diacrylate-polydimethylsiloxane (PAPDMS) was used as a slurry additive to form a protective layer on LCO.
• Electrochemical cycling tests were performed at 4.5 V to evaluate capacity retention.
• Pouch cells were assembled to assess long-term stability in a practical configuration.

Main Results:

• The PAPDMS layer improved electronic conductivity, mechanical flexibility, and electrolyte uptake of LCO.
• The protective layer modulated solvation structure, promoted inorganic-rich CEI formation, and suppressed transition metal dissolution.
• Modified LCO showed increased capacity retention from 62.3% to 85.2% after 200 cycles at 4.5 V.
• In pouch cells, PAPDMS-modified LCO retained 78.2% capacity after 500 cycles, compared to 46.8% for pristine LCO.

Conclusions:

• The PAPDMS protective layer effectively stabilizes high-voltage LCO cathodes.
• This strategy offers a scalable approach for improving the longevity of LCO in advanced lithium-ion batteries.