Cerium-based metal–organic framework-conducting polymer nanocomposites for supercapacitors

Nanocomposites consisting of a cerium-based metal–organic framework (Ce-MOF-808) and a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), are synthesized by performing the pulse electrodeposition of PEDOT within the Ce-MOF-808 thin films. Ratios between MOF and PEDOT in the composites are tunable by simply adjusting the charge density used for electropolymerization, and the crystallinity, morphology, and elemental distributions of the resulting nanocomposites are characterized. Electrochemical behaviors and capacitive performances of the pristine MOF, pristine PEDOT thin films, and composite thin films are investigated with the use of the neutral sodium sulfate aqueous electrolytes. The reversible electrochemical reactivity of the highly porous Ce-MOF-808 provides a pseudocapacitance, and the electronically conducting PEDOT can not only offer a remarkable double-layer capacitance but also facilitate the electronic conduction between the redox-active cerium sites present in the MOF. As a result, the composite can outperform both the pristine MOF and pristine electrodeposited PEDOT as the active materials for supercapacitors. Findings here suggest that the highly porous and redox-active cerium-based MOF thin films are capable to enhance the capacitive performances of the electrodeposited PEDOT thin films.