Application of Ni/Co-based metal–organic frameworks (MOFs) as an advanced electrode material for supercapacitors

A Ni/Co-based bimetallic metal-organic framework (Ni/Co-MOF) [CoNi(mu(3)-tp)(2)(mu(2)-pyz)(2)] (tp = terephthalic acid and pyz = pyrazine) was synthesized through a hydrothermal method. Structural characterization revealed that metal centers are equally occupied by Co2+ and Ni2+ ions. The supercapacitive behavior of the synthesized Ni/Co-MOF was evaluated using cyclic voltammetry (CV), galvanostatic charge/ discharge, and electrochemical impedance spectroscopy (EIS) measurements in 3 M KOH as electrolyte. The Ni/Co-MOF exhibited an outstanding specific capacitance of 1049 F g(-1) at a discharge current density of 1 A g(-1), good rate capability (642 F g(-1) at 10 A g(-1)), and 97.4% capacitance retention after 5000 cycles. To the best of our knowledge, this is the first bimetallic MOF that is used in supercapacitors and its encouraging properties indicate that Ni/Co-MOF can be a promising candidate as an advanced electrode material for supercapacitors.