POS6-0191
Dual-Function Tetrazine-Based Covalent Organic Frameworks for Stable Lithium Metal Anodes: Synergistic Regulation of Anion Trapping and Electronic Insulation.
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Yeong Hun Jeong (Seoul national university)
Co-Author(s)
Abstract
Lithium (Li) metal anodes are ideal candidate materials for next-generation batteries owing to their high theoretical capacity (3860 mAh g-1) and low reduction potential. However, non-uniform solid electrolyte interphase (SEI) formation and uncontrolled dendritic Li growth severely limit their practical applications. To resolve these issues, we introduce a crystalline, well-ordered tetrazine-based Covalent Organic Framework (COF) as a dual-functional artificial protective layer. Density functional theory (DFT) calculations and 7Li NMR spectroscopy revealed that the nitrogen-rich, electron-deficient sites of the tetrazine framework possess an intrinsically lithiophilic nature, ensuring an ordered Li+ flux by effectively trapping anions. Crucially, Kelvin Probe Force Microscopy (KPFM) was employed to evaluate the interfacial energetics after electrochemical cycling. The surface potential profile of the COF@Li system shifted completely into the negative regime, delivering a highly uniform average value of -252 mV compared to the severe fluctuations of bare Li (+2880 mV). Statistical analysis demonstrated that the COF@Li interface exhibits an exceptionally high absolute work function of 4.85 eV over bare Li (1.49 eV), providing a robust energy barrier that ensures robust electronic insulation and suppresses parasitic electrolyte decomposition. The practical efficacy of this protective layer was corroborated through comprehensive electrochemical tests. Galvanostatic cycling and distribution of relaxation time (DRT) analyses confirmed that the COF@Li anode maintains a highly stable voltage profile and consistently low interfacial resistance. Furthermore, when paired with a LiNi0.8 Co0.1Mn0.1O2 (NCM811) cathode, the COF@Li||NCM811 full-cell exhibited significantly enhanced cycling life and Coulombic efficiency. This work provides a design strategy for crystalline, multi-functional polymer/COF interfaces to achieve safe and high-performance Li metal batteries.
