Spindle-like Ni3(HITP)2 MOFs: Synthesis and Li+ storage mechanism

Abstract

Metal-organic frameworks (MOFs) with intrinsic pores and redox organic ligands/metallic ions have been viewed as the promising anodes with high capacity in lithium ion batteries (LIBs). However, conventional MOFs faces the disadvantages of poor electron conductivity and weak coordinate bond between organic ligands and central metal ions, inhibiting the application in LIBs. In this study, a conductive MOFs of Ni3(HITP)2 has been fabricated by reacting the strong-field ligand of 2,3,6,7,10,11-hexaiminotriphenylene (HITP) with Ni2+. The as-prepared Ni3(HITP)2 presents the spindle-like shape that are regular arranged by multi-nano fibers. While utilized in LIBs, Ni3(HITP)2 can deliver the reversible capacity of 703 mAh g−1 at 50 mA g−1 with almost no capacity fading. According to the theoretical calculation and XPS results, both amino groups in ligand and Ni2+ ions have participated in the redox reaction during the charge/discharge processes. The superior Li+ storage performance of Ni3(HITP)2 are contributed by the intercalation capacity of the redox groups and capacitance of the molecular pores.