Interfacial-Derived Catalytic Engineering within Conjugated Porous Organic Polymer Stabilizes Lithium Metal Anode

Abstract

Unstable native solid electrolyte interphase (SEI), non-uniform Li+ flux, and dendritic Li growth severely restrict the practical use of lithium metal anodes. Herein, we report a porphyrin–perylene imide porous organic polymer (TP-POP) as an electrolyte-decomposition-directing artificial interphase for stable lithium metal anodes. Benefiting from extended π-conjugation, high aromaticity, intrinsic microporosity, and abundant N/O-rich active sites, TP-POP simultaneously anchors Li+ and preferentially adsorbs electrolyte anions. Calculations show stronger local association of TP-POP with TFSI– and NO3– than with DME and DOL, Li+ binding at representative N sites, and adsorption-induced changes in the electronic structure of the resulting complexes. Depth-resolved XPS after cycling identifies a compositionally graded interphase containing LiF, Li–O/Li2O-related, and Li3N-related species. Consequently, TP-POP@Li exhibits an increased Li+ transference number of 0.588, a reduced Li nucleation overpotential of 68.94 mV, and stable Li plating/stripping for over 3500 h at 1 mA cm–2/1 mAh cm–2. When paired with LiFePO4, TP-POP@Li retains 95.6% capacity after 1000 cycles at 3 C. This work provides a molecular interphase strategy for directing electrolyte decomposition and stabilizing lithium metal anodes.