Porous Cobalt Metal–Organic Frameworks as Active Elements in Battery–Supercapacitor Hybrid Devices

Abstract

With the trigonal linker 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid as a building block, porous cobalt metal–organic frameworks (named as PCN) have been successfully prepared and directly utilized as active materials in alkaline battery-type devices. For comparison, their carbon-supported hybrids (CNFs/PCN) have also been employed as battery-type electrodes. We found that the pristine PCN displayed a better performance than the CNFs/PCN composite electrode in electrochemical cells. To further investigate their electrochemical performances, alkaline battery–supercapacitor hybrid (BSH) devices with these materials as positive electrodes and activated carbon (AC) as the negative electrode were fabricated. The results indicate that the PCN//AC BSH devices delivered a maximum energy density of 16.0 Wh kg^–1 at a power density of 749 W kg^–1 within the voltage range of 0–1.5 V, which are much higher than those of CNFs/PCN//AC devices (12.4 Wh kg^–1 at 753 W kg^–1).