Surface and Diffusion Characteristics of Nanoporous UiO-66/Pineapple Peel-Derived Carbon Composites for Solid-State Supercapacitors

Abstract

Supercapacitors (SCs) based on hierarchical nanoporous framework composite materials and aqueous electrolytes are recent interests for the researchers. The structure of UiO-66 exhibits extraordinary stability and high specific surface area, but the specific capacitance of UiO-66 (139.4 F g −1 at 2 A g −1 ) is limited due to its moderately conducting nature. Therefore, we report a method to modify UiO-66 with pineapple peel derived activated carbon (PA-AC) to form a facile composite. Owing to the high specific surface area and good conductivity of the UiO-66/PA-AC composite, a high specific capacitance of 295.9 F g −1 at 2 A g −1 has been achieved and is well suited for supercapacitor applications. At the maximum charging voltage range of 0−1.8 V, the UiO-66/PA-AC//UiO-66/PA-AC symmetrical SC delivered a maximum energy density of 29.6 Wh kg −1 at a power density of 170 W kg −1 . After 5000 repeated charge−discharge cycles at 30 A g −1 , the specific capacitance of the device increased from 100% to 120% of its initial specific capacitance. This study emphasized the potential importance of incorporating MOFs into pores of biowaste derived carbon as a strategy for enhancing the charge storage kinetics of moderately conducting MOFs.