Electrochemical Properties of Electrospun Metal-Organic Frameworks (MOFs) Nanofibers as Novel Hybrid Electrode Materials

Abstract

Abstract This research focuses on exploring the electrochemical properties of UiO-66 and MOF-199 (metal-organic framework (MOFs)-based electrodes, in the form of nanofibers fabricated along with PVDF through electrospinning techniques on a pencil graphite electrode (PGE). SEM images obtained showed the UiO66/PVDF and MOF199/PVDF nanofibers have different morphology affected by addition of different MOF into the PVDF polymers with mean diameters of 750 nm and 750 nm respectively. TGA results indicated that the nanofibers possess a high thermal degradation temperature, exceeding 400°C, which indicates increased material robustness compared to the pure MOFs alone. Mechanical strength analysis of the nanofibers revealed contrasting mechanical properties. UiO66/PVDF exhibited a strain percentage of 309.4 but a relatively low stress value of 0.4299 MPa. On the other hand, MOF199/PVDF displayed a high stress value of 3.718 MPa but a lower strain percentage of 46.34%. Electrochemical studies were conducted on the electrodes; MOFs/PVDF/PGE and the MOFs/GCPE (carbon paste electrodes) to compare MOFs’ standalone electrochemical properties. Different scan rates were applied to all electrodes in the interval of 5, 20, 50 100, and 250 mVsec-1 and the best Cs values were obtained from the MOF199/PVDF/PGE nanofiber electrode. Furthermore, prolonged charge-discharge measurements were executed using a scan rate of 100 mV/sec across 200 cycles for all electrodes. This phase was extended to 3000 cycles exclusively for the MOF199/PVDF/PGE nanofiber electrode. The outcomes underscored remarkable stability, particularly notable in the case of the MOF199/PVDF/PGE nanofiber electrode, highlighting its potential as a reliable energy storage electrode.