Highly stable supercapacitive performance on a copper-based co-crystal complex

The article discusses the synthesis and characterization of a new Cu-based complex, [Cu(Hpz)4SO4]]•[Cu(Hpz)4(H2O)SO4]•H2O (1), obtained via solvothermal method with the ligand 1H-pyrazole (Hpz). The complex exhibits a co-crystal structure composed of two independent units. The crystal structure was further confirmed by PXRD Rietveld refinement. In three-electrode system tests, the electrode made from this co-crystal complex displayed a high specific capacitance and a good cycling stability. At a scan rate of 3 mV s−1, the maximum specific capacitance was 242.4 F g−1, and after 2000 cycles at a current density of 2 A g−1 in a 1 M KOH solution, a capacitance of 95.5% was retained.