Pristine Co(BDC)TED0.5 a pillared-layer biligand cobalt based metal organic framework as improved anode material for lithium-ion batteries

Abstract

Pillared-layer framework MOFs are considered to be energetic for enhanced performance for anode materials because of rich space and channels for lithium insertion and extraction. We selected pillared-layer MOF, Co(BDC)TED0.5, consisting of an aromatic organic ligand (Terephthalic acid: 1,4-H2BDC) and pillar ligand (Triethylenediamine: TED), synthesized via facile hydrothermal approach and investigated as anode material for LIBs. The time-dependent reaction kinetics of this MOF were investigated to optimize MOF as anode material. The Co(BDC)TED0.5@24h exhibits good rate capability (614 and 239 mAh g−1 at 0.2 and 2.0 A g−1, respectively) with excellent cyclic stability, which is up to 808.2 mAh g−1 after 1000 charge/discharge cycles at 1.0 A g−1 current density. Such an impressive lithium performance is mainly due to channels provided by a pillared-layer framework which not only provides the space for insertion/extraction of Li+ ions but also mitigates the volume expansion during the cycles. The electrochemical process of Co(BDC)TED0.5@24h electrode is elucidated by in-depth series of ex-situ XRD, FTIR, and XPS studies at different charge/discharge states which anticipates the intercalation as working mechanism for Co(BDC)TED0.5. The DFT calculation is also utilized to further confirm the potential binding sites responsible for electrochemical behavior of Co(BDC)TED0.5 as anode materials for LIBs.