Highly stable supercapacitive performance of a (3, 4, 6‐c)‐connected 2D Co‐MOF

Abstract

AbstractTwo‐dimensional (2D) metal–organic frameworks (MOFs) used directly in supercapacitors have been a worldwide research interest for their potential high performance. Herein, one new 2D Co‐based MOF, [CoCo0.5Co0.5(μ–ppa)2(H2O)3]n, namely, (BBU‐1), has been synthesized through solvothermal method with the ligand H2ppa (H2ppa = 3‐(pyrazin‐2‐yl)‐1H‐pyrazole‐5‐carboxylic acid). Single X‐ray diffraction analysis shows that the BBU‐1 exhibits a (3, 4, 6‐c)‐connected 2D structure bridged through the carboxylic group, with the topological point symbol of {3·4·5}2{32·42·52·62·74·82·9}{32·62·72}. PXRD Rietveld refinement also has been employed to confirm the structure. The Co‐MOF electrode showed a high specific capacitance and a good cycling stability. Its maximum specific capacitance was 134.5 F g−1 at 3 mV s−1, and the specific capacitance retention is about 91.3% after 1000 cycles at a current density of 2 A g−1 in the 2‐M KOH solution. These results show that the pristine 2D Co‐MOF is an excellent candidate of electrode active material for electrochemical energy storage.