Enhancing Anion-Selective Catalysis for Stable Lithium Metal Pouch Cells through Charge Separated COF Interlayer.

Regulating the composition of solid-electrolyte-interphase (SEI) is the key to construct high-energy density lithium metal batteries. Here we report a selective catalysis anionic decomposition strategy to achieve a lithium fluoride (LiF)-rich SEI for stable lithium metal batteries. To accomplish this, the tris(4-aminophenyl) amine-pyromeletic dianhydride covalent organic frameworks (TP-COF) was adopted as an interlayer on lithium metal anode. The strong donor-acceptor unit structure of TP-COF induces local charge separation, resulting in electron depletion and thus boosting its affinity to FSI. The strong interaction between TP-COF and FSI lowers the lowest unoccupied molecular orbital (LUMO) energy level of FSI, accelerating the decomposition of FSI and generating a stable LiF-rich SEI. This feature facilitates rapid Li transfer and suppresses dendritic Li growth. Notably, we demonstrate a 6.5 Ah LiNiCoMnO|TP-COF@Li pouch cell with high energy density (473.4 Wh kg) and excellent cycling stability (97.4 %, 95 cycles) under lean electrolyte 1.39 g Ah, high areal capacity 5.7 mAh cm, and high current density 2.7 mA cm. Our selective catalysis strategy opens a promising avenue toward the practical applications of high energy-density rechargeable batteries.