High-performance asymmetric supercapacitor enabled by three-dimensional zinc-based metal-organic framework

To overcome the disadvantage of relatively low energy density in supercapacitors, one way is to seek new electrode materials with high specific capacity. Here, a novel three-dimensional metal-organic framework [Zn(BGPD)(H 2 O) 2 ] (Zn-BGPD; BGPD = N , N ′-bis(glycinyl)pyromellitic diimide) was synthesized via the reaction between Zn(NO 3 ) 2 ·6H 2 O and BGPD in dimethylformamide. Zn-BGPD was characterized by IR spectra, powder X-ray diffraction, thermogravimetric analysis, field emission scanning electron microscope, transmission electron microscope and X-ray single-crystal structure analysis. In a three-electrode device, Zn-BGPD showed an excellent specific capacitance of 574 F g −1 at a current density of 1 A g −1 when it was used as an electrode material for supercapacitors. Impressively, the asymmetric supercapacitor (ASC) based on Zn-BGPD and reduced graphene oxide (rGO) exhibited a capacitance of 59.4 F g −1 at 1 A g −1 , the highest energy density of 21.1 Wh kg −1 at 1 A g −1 , and the highest power density of 4.72 kW kg −1 at 6 A g −1 , along with higher cycle stability (97.4% capacitance retention after 4000 cycles at 1 A g −1 , and 85.8% capacitance retention after 10,000 cycles at 4 A g −1 ). Our work verifies that Zn-BGPD//rGO ASC is an application promising energy storage device, and provides a new pathway for developing high-performance MOF based materials with low-cost and environmentally friendly for supercapacitors.