A novel CDs coated polyoxometalate/metal-organic framework composite for supercapacitors

Abstract

Considering the high electrical conductivity of carbon dots (CDs) and good oxidation-reduction property of polyoxometalates (POMs), a novel CDs coated POMs /metal organic frameworks (POMOFs) composition structure, [email protected]12/Ni-MOF, was prepared by hydrothermal reaction in this work. PMo12 was encapsulated in the Ni-MOF framework to form the POMOF composite material, which realized the fixation of water-soluble [PMo12O40]3- (PMo12). A comparison study on the cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) of the resulting [email protected]12/Ni-MOF with different compositions revealed that [email protected]12/Ni-MOF was better formulation in terms of specific capacity (748.8 C·g−1 at 1 A·g−1) and rate performance (75.93 % at 10 A·g−1). Furthermore, a hybrid supercapacitor device was assembled using [email protected]12/Ni-MOF as positive electrode and activated carbon (AC) as negative electrode, which showed an high energy density of 39.22 Wh·kg−1 under 749.9 W·kg−1 and excellent cyclic stability (98.4 % for 20000 cycles at 5 A·g−1).