Cycling Stability of a 2D Pristine MOF Supercapacitors

Graphical A cobalt-based layered MOF ([Co 2 (μ-SO 4 )(Hppza) 2 (H 2 O) 3 ] n (SEU-1) has been successfully constructed and comprehensively characterized. The maximum specific capacitance of SEU-1 is 145.5 F g −1 at 1 A g −1 , along with the specific capacitance retention of 92.7 % at the current density of 5 A g −1 after 6000 cycles in 3 M KOH solution, suggesting SEU-1 can be applied to high performance SC. Two-dimensional (2D) metal–organic frameworks (MOFs) have been a worldwide research interest due to their potential application in supercapacitors. Herein, a cobalt-based layered MOF ([Co 2 (μ-SO 4 )(Hppza) 2 (H 2 O) 3 ] n , namely, SEU-1 ; H 2 ppza=3-(pyridin-4-yl)-1 H -pyrazole-5-carboxylic acid) has been synthesized via a one-step solvothermal method. Single X-ray diffraction analysis shows that the SEU-1 exhibits a (3,3,4)-connected 2D structure with a Schläfli symbol of (6 2 ⋅ 8)(6 3 )(6 4 ⋅ 8 ⋅ 10). Variable-temperature magnetic susceptibility data display that antiferromagnetic interactions between two Co II ions exist in SEU-1 . The supercapacitive performance has been evaluated in the three-electrode system. Its maximum specific capacitance is 145.5 F g −1 at 1 A g −1 , along with the specific capacitance retention of 92.7 % at the current density of 5 A g −1 after 6000 cycles in 3 M KOH solution. These results demonstrate that SEU-1 is a good candidate for electrode material for electrochemical energy storage.