Conformal Prelithiation Nanoshell on LiCoO₂ Enabling High-Energy Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Initial lithium loss in lithium-ion batteries (LIBs) significantly reduces energy density, particularly in Si-anode systems.
• This irreversible loss necessitates effective prelithiation strategies to maintain battery performance.

Purpose of the Study:

• To develop a high-capacity, built-in prelithiation reagent for LiCoO2 cathodes.
• To compensate for initial lithium losses and enhance the overall energy density of LIBs.

Main Methods:

• In situ chemical formation of a conformal Li2O/Co nanoshell (approx. 20 nm) on LiCoO2 particles.
• Electrochemical characterization of LiCoO2 cathodes with and without the Li2O/Co nanoshell in full cells with graphite-SiO anodes.

Main Results:

• A 15 mAh g-1 increase in overall charge capacity was observed for LiCoO2 with 1.5 wt% Li2O/Co due to irreversible lithium extraction from the nanoshell.
• Full cells using the prelithiated LiCoO2 cathode showed an 11% higher discharge capacity (2.60 mAh cm-2 vs. 2.34 mAh cm-2 at 0.1 C) compared to pristine LiCoO2.
• Stable battery cycling performance was demonstrated for the cells utilizing the prelithiated cathode.

Conclusions:

• The Li2O/Co nanoshell serves as an effective high-capacity prelithiation reagent for LiCoO2 cathodes.
• This approach successfully compensates for initial lithium loss, improving battery capacity and cycling stability.
• The prelithiated LiCoO2 is compatible with existing battery fabrication processes, indicating its practical viability.