Polyoxometalates-Based Metal-Organic Frameworks Made by Electrodeposition and Carbonization Methods as Cathodes and Anodes for Asymmetric Supercapacitors.

Hybrid materials have obtained well-deserved attention for energy storage devices, because they show high capacitances and high energy densities induced by the synergistic effect between complementary components. Polyoxometalate-based metal-organic frameworks (POMOFs) possess the abundant redox-active sites and ordered structures of polyoxometalates (POMs) and metal-organic frameworks (MOFs), respectively. Here, an asymmetric supercapacitor (ASC) NENU-5/PPy/60//FeMo/C was fabricated in which both its electrodes are prepared from POMOF precursors.

Crystal structure of catena-poly[[[tetra-aqua-zinc(II)]-μ-1,4-bis-[4-(1H-imidazol-1-yl)benzo-yl]piperazine] dinitrate monohydrate].

In the title polymeric complex, {[Zn(C24H22N6O2)(H2O)4](NO3)2·2H2O} n , the Zn(II) cation, located about a twofold rotation axis, is coordinated by two imidazole groups and four water mol-ecules in a distorted N2O4 octa-hedral geometry; among the four coordinate water mol-ecules, two are located on the same twofold rotation axis. The 1,4-bis-[4-(1H-imidazol-1-yl)benzo-yl]piperazine] ligand is centro-symmetric, with the centroid of the piperazine ring located on an inversion center, and bridges the Zn(II) cations, forming polymeric chains propagating along [201]. In the crystal, O-H⋯O and weak C-H⋯O hydrogen bonds link the polymeric chains, nitrate anions and solvent water mol-ecules into a three-dimensional supra-molecular architecture.