Li₂Se as a Cathode Prelithiation Additive for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Conventional lithium-ion batteries (LIBs) suffer from irreversible lithium (Li) loss during solid electrolyte interphase (SEI) formation, reducing energy density.
• This Li loss necessitates compensation strategies, typically through prelithiation additives, to maintain battery performance and longevity.

Purpose of the Study:

• To introduce lithium selenide (Li2Se) as a novel cathode prelithiation additive for LIBs.
• To evaluate the efficacy of Li2Se in compensating for irreversible Li loss and enhancing battery energy density.

Main Methods:

• Investigated the electrochemical behavior of Li2Se as a prelithiation additive in LiFePO4 (LFP) cathodes.
• Conducted electrochemical characterizations, including capacity and energy density measurements, in half Li||LFP cells.

Main Results:

• Addition of 6 wt% Li2Se to LFP cathodes resulted in a 9% increase in initial specific capacity.
• Achieved a 19.8% enhancement in energy density without compromising other battery performance metrics.
• Li2Se delithiation provides high specific capacity, avoids gas release, and is compatible with carbonate electrolytes.

Conclusions:

• Lithium selenide (Li2Se) is a highly efficient prelithiation additive for LIBs.
• Li2Se offers a viable solution for developing high-energy LIBs by mitigating irreversible lithium loss.