Metal-organic frameworks based on ternary transition metal ions for high-performance lithium ion batteries

Metal-organic frameworks (MOFs) materials have been widely researched in energy conversion systems because of porosity and active sites. However, applying MOF as an electrode material remains challenging because of its structural instability. In this work, two novel materials are designed to promote the research of MOFs-based electrode materials for lithium-ion batteries (LIBs). Two ternary metallic ions (Mn2+, Co2+, Ni2+) constituent MOFs with two- and three-dimensional (3D) structures are synthesized by combining with benzene-1,2,3,4,5,6-hexacarboxylate (BHC) ligand via a simple hydrothermal method. The structures of MCN-1 and MCN-2 belong to monoclinic symmetry, C2/c space group. The 3D structure of MCN-2 can enhance the interfacial contact between electrode materials and electrolytes and provide more active sites for the storage of Li+. Electrochemical experiments show that the 3D structure ternary MOF delivers an ultra-high capacity of 807.3 mAh g-1 after 100 cycles at 100 mA g-1, even though a phase transition occurs during the electrochemical process. This superior performance is rationally owing to the synergetic mechanism of intercalation/deintercalation combined with capacitance behavior, which has broad application prospects as anode material.