Nickel metal-organic framework nanoparticles as electrode materials for Li-ion batteries and supercapacitors

Nickel-based metal-organic framework ([Ni(4,4'-bpy)(tfbdc)(H2O)(2)], Ni-MOF) nanoparticles with the size of 45-250 nm were synthesized by a facile hydrothermal route in combination with a grinding treatment (4,4'-bpy = 4,4'-bipyridine, H(2)tfbdc = tetrafluoroterephthalic acid). The materials were characterized by elemental analysis, IR spectrum, thermogravimetric analysis, powder X-ray diffraction, X-ray photoelectron spectrum (XPS), transmission electron microscope (TEM), scanning electron microscope (SEM), and the Brunauer-Emmett-Teller (BET) surface. As electrode materials for supercapacitors, the Ni-MOF nanoparticles delivered a high specific capacitance of 2548 F g(-1) in 1 M KOH solution at a current density of 1 A g(-1). When applied as anode materials of Li-ion batteries, the Ni-MOF nanoparticles displayed a higher reversible capacity, a better cyclic stability, and a higher rate performance, which still maintained 406 mAh g(-1) after 50 cycles at a current density of 50 mA g(-1). The better electrochemical performances may be attributed to the unique structure feature, and short route for electrolyte/Li-ions diffusion in nanosized Ni-MOF.