Reconstruction of Solid Electrolyte Interphase with SrI₂ Reactivates Dead Li for Durable Anode-Free Li-Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Anode-free lithium-metal batteries (AFLMBs) offer a promising path to safe and cost-effective lithium-metal batteries.
• However, conventional AFLMBs suffer from limited cycle life due to dead lithium accumulation, electrolyte depletion, and poor Li+ transfer at the solid electrolyte interphase (SEI).

Purpose of the Study:

• To address the short cyclic life of AFLMBs by suppressing dead lithium formation.
• To enhance the stability and efficiency of the solid electrolyte interphase (SEI) in AFLMBs.

Main Methods:

• Modification of a carbon paper (CP) current collector with strontium iodide (SrI2).
• Investigation of synergistic mechanisms including reversible redox reactions, dielectric SEI formation, and enhanced Li+ transfer.
• Electrochemical testing of NCM532/CP cells.

Main Results:

• SrI2 introduction effectively suppressed dead lithium accumulation.
• The modified SEI exhibited a dielectric surface (SrF2 and LiF) and a highly ionic conductive inner layer (LiI).
• The NCM532/CP cell achieved a capacity of 129.2 mAh/g after 200 cycles.

Conclusions:

• SrI2-modified current collectors significantly improve the cyclic performance of AFLMBs.
• The synergistic effects of SrI2 enable reversible dead lithium reactivation, prevent electrolyte decomposition, and facilitate efficient Li+ transfer.
• This approach offers a viable strategy for developing highly safe and long-lasting AFLMBs.