Aza-triphenylene-based covalent organic framework: Anode for high-efficiency sodium-ion batteries

This research examines the suitability of newly synthesized aza-triphenylene based covalent organic framework (aza-COF) as a negative electrode material for sodium-ion batteries (SIBs) through first-principles density functional theory. This work identifies the two-dimensional aza-COF as a direct band gap semiconductor with an energy gap of 1.02 eV. When sodium is loaded at the most reliable location, the aza-COF system changes from a semiconductor to a metallic state, leading to improved electrical conductivity. Aza-COF shows a diffusion barrier of 0.78 eV, a high theoretical specific capacity of 602.3 mAhg⁻¹, an energy density of 1259.5 mWhg⁻¹, and mean voltage of 0.62 V falling within the ideal range of 0.1–1.0 V. Additionally, its structural adaptability further supports its suitability for such applications. Also, aza-COF demonstrates a strong affinity for electrolytes highlighting its exceptional suitability for electrode applications. These compelling theoretical results indicate that aza-COF could function as a highly efficient anode material for SIBs