Flower-like Ni3(NO3)2(OH)4@Zr-metal organic framework (UiO-66) composites as electrode materials for high performance pseudocapacitors

Zr-metal organic frameworks (Zr-MOFs, UIO-66) as a kind of crystalline porous material possess controllable porous structure and strong thermal stability up to 753 K. In this paper, we synthesized Ni 3 (NO 3 ) 2 (OH) 4 , Zr-MOF with high specific surface area (1073 m 2 g −1 ) and Ni 3 (NO 3 ) 2 (OH) 4 @Zr-MOF composite for pseudocapacitor material. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were taken to characterize the structure and morphology of Ni 3 (NO 3 ) 2 (OH) 4 , Zr-MOF, and Ni 3 (NO 3 ) 2 (OH) 4 @Zr-MOF. The porous structure of Zr-MOF favors the utilization of the active material Ni 3 (NO 3 ) 2 (OH) 4 and interfacial charge transport and provides short diffusion paths for ions, which results in a high specific capacitance. Electrochemical properties are evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge measurement. A maximum specific capacitance (SC) of 992 F/g was obtained from CV at a scan rate of 5 mVs −1 , which is higher than Zr-MOF (∼134 F g −1 ) and Ni 3 (NO 3 ) 2 (OH) 4 (∼753 F g −1 ). Meanwhile, the Ni 3 (NO 3 ) 2 (OH) 4 @Zr-MOF composite electrode exhibits a good cycling stability over 3000 cycles.