Piperazine-based two-dimensional covalent organic framework for high performance anodic lithium storage

The controllably spatial and chemical structures and abundantly elemental reserves of covalent organic frameworks (COFs) endow them the potential of being applied in next generation of electrochemical lithium-ions storage with high performances. Here, a piperazine-based two-dimensional covalent organic framework (PTDCOF) is designed and synthesized. PTDCOF is constructed by triphenylene units through irreversible piperazine linkages to afford the regular in-plane pores sized ~11 Å. PTDCOF is charactered with few-layered features, which is crystalized through eclipsed (AA) and staggered (AB) stacking modes together. And the synthesized framework exhibits excellent stability upon harsh chemical environments. As the active material of anodic lithium storage, the guest-eliminated product derived by PTDCOF demonstrates remarkable lithiation (1644.3 mAh g − 1 capacity contribution at 0.1 A g − 1), rate and cycling performances. The abundant active sites lead to a high and reversible lithium loading of at least 14 lithium atoms per triphenylene unit (Li14(C18N3H9)). Such product presents superior anodic lithiation capability comparing with previously reported carbonaceous materials. This study provides a possible and attractive path for hunting the high performances of lithium or other metal ions storage systems.