In-situ co-growth LiF/LiBr rich SEI for the prevention and remediation of dead lithium.

Authors

Kun Zeng, Qi An, Qing Liu, Cuiping Luo, Guiqaun Zhao, Lu Liu, Yunchun Zha, Haiye Zhu, Hong Guo

Published in

Science bulletin. Sep 15, 2026. Epub Sep 15, 2026.

Abstract

Solid electrolyte interphase (SEI) instability and dead Li accumulation remain persistent challenges for lithium metal batteries. Although considerable efforts have been devoted to optimizing the SEI composition, the issue of dead lithium accumulation remains largely neglected. Herein, we design a covalent organic framework (COF)-based dual-functional separator to regulate the chemical composition of the solid electrolyte interphase to form a LiF/LiBr-rich SEI, while simultaneously introducing Br^-/Br₃^- redox couple in-situ at the interface for dead lithium reactivation. Both theoretical and experimental evidence demonstrate that the introduction of TPPA-Br triggers cleavage of the C-Br bond, leading to the in-situ formation of an ionically conductive LiF/LiBr-rich SEI. The LiF can promote uniform lithium deposition and prevent dead Li formation. Meanwhile, the LiBr can result in Br^-/Br₃^- redox couple, which further chemically reactivates Li₂O and electrically isolates Li⁰, mitigating capacity decay associated with dead Li accumulation. Consequently, Li||LiFePO₄ cells employing TPPA-Br functional separators display good cycling stability over 1200 cycles with 90.1% capacity retention at 1 C (1 C=170 mA g^-1), confirming the practical potential of this interphase-regulation strategy.

PMID:
42816268
Bibliographic data and abstract were imported from PubMed on 01 Oct 2026.

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