Self-Assembled Cobalt-Nickel Bimetallic-Organic Framework Materials with High Supercapacitor Performance

A series of novel 2D MOFs with a layeredstructure weresynthesized by a one-step solvothermal method, including Co-MOF, Ni-MOF,and Co x Ni y -MOFs. The obtained hybrid supercapacitor based on NF/Co2.75Ni1-MOF (cathode) and NF/AC (anode) delivers a high energydensity of 20.44 Wh kg(-1) at a power density of 387.49W kg(-1), with a high cycling stability of 85.4% over15,000 cycles. Twonew metal-organic frameworks (MOFs), [Co-(bcpp)-(bbip)]center dot H2O (Co-MOF) and [Ni-(bcpp)-(bbip)]center dot H2O (Ni-MOF),have been generated based on a V-type flexible carboxylic ligand 3,5-bis-(4-carboxylphenoxy) pyridine (H(2)bcpp) and a rigid N-donor ligand 1,1 '-(1,4-phenylene)-bis-(1H-benzimidazole) (bbip) by a solvothermal method. Co-MOFand Ni-MOF are isostructural with a 2-fold interpenetrated layeredstructure. Moreover, a series of bimetallic Co x Ni y -MOFs (x/y = 1:1, 2.5:1, 2.75:1, 3:1, 3.25:1, and 3.5:1) were obtainedby using one-pot synthesis. Owing to their mixed metallic componentsand internal layered structure, the bimetallic Co x Ni y -MOFs possess a remarkable electrochemicalstorage property. Significantly, the Co2.75Ni1-MOF has high specific capacitance (699 F g(-1))at 0.5 A g(-1) and good cycling durability (retained72.7% over 3100 turns). Additionally, an asymmetrical ultra-capacitorbased on Co2.75Ni1-MOF and activated carbon(AC) delivers a maximum energy density of 20.44 Wh kg(-1) at 387.49 W kg(-1) and a high cycle-to-cycle stabilitywith 85.4% of the primary capacitance over 15,000 turns.