Covalent organic framework with high capacity for the lithium ion battery anode: insight into intercalation of Li from first-principles calculations

Covalent organic frameworks (COFs) generally have high stability, large charge capacity and wide ion diffusion paths, and they may serve as the potential electrode materials for lithium ion batteries. Here we explored the structural, electronic, and lithium-storage properties of the newly synthesized NUS-2 COF material by first-principles calculations. The present results indicate that the micropore environment and the presence of the carbonyl oxygens in the NUS-2 COF can prevent the formation of lithium dimer and the aggregation of lithium bulk, which can improve lithiation efficiency. The predicted maximum theoretical capacity is as high as 742.8 mAh g(-1) and the average cell voltage varies from 3.35 V for Li@NUS-2 to 2.04 V for 14Li@NUS-2, suggesting that the NUS-2 COF material should be a quite suitable lithium-storage anode material.