Keplerate-type polyoxometalates represent a large series of high nuclear molecular clusters; for example, (NH ) [Mo Mo O (CH COO) (H O) ] ({Mo }) is a kind of spherical heteropoly blue with a large overall negative charge and an electron density and topological structure similar to C . {Mo } is a good bifunctional material that can be used as an electron acceptor or donor, which is advantageous to accelerate electron transmission in supercapacitors. Herein, a nanocomposite of rGO functionalized with a Keplerate-type polyoxometalate {Mo } was prepared by a facile chemical reduction method and used to construct supercapacitors for the first time. The electrochemical performance of the supercapacitors can be significantly improved due to the excellent redox properties, high electronegativity, and hollow porous structures of {Mo }, in addition to the outstanding conductivity of rGO. The {Mo }-rGO nanocomposite electrode exhibited an excellent gravimetric specific capacitance of 617.3 F g at a current density of 5 A g in 1 m Li SO electrolyte. An aqueous asymmetric supercapacitor with a voltage range of 2.1 V, with the {Mo }-rGO nanocomposite as the negative electrode and modified activated carbon as the positive electrode, exhibited a high energy density of 31.6 Wh kg with a power density of 207.7 W kg and favorable cycling stability.

It is known that the electron-holes recombination exsisting in the Dye-sensitized solar cells (DSSCs) limits the increasing of the efficiency of the cells. Finding suitable materials to modify TiO2 semiconductor...

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Supercapacitors are energy storage equipment that have attracted particular attention owing to its wide operating temperature range, high-power density, and small size, whereas the limited energy density has always been a main obstacle in many applications. Composite materials have a forward-looking application value in the manufacture of innovative supercapacitors due to the synergistic effect between various components. We propose a plain oxidative polymerization method to prepare the polyoxometalate-based metal-organic framework/polypyrrole composites (PW 12 @MIL-101/PPy-n, n represents the volumes of pyrrole) toward supercapacitor electrodes for the first time. PW 12 @MIL-101 possesses rich and fully accessible active sites as well as regular porosity provided by PW 12 and MIL-101(Fe), respectively. PPy can effectively meliorate the conductivity of PW 12 @MIL-101 by accelerating the Faradaic process at the surface, and then facilitate electron/ion transfer between PW 12 @MIL-101 nanocrystallines. As a result, PW 12 @MIL-101/PPy-0.15 composite has a noticeably higher specific capacitance (1217 mF • cm À 2 ), which is better than PW 12 @MIL-101 (158 mF • cm À 2 ) and MIL-101 (117 mF • cm À 2 ). Meanwhile, the relevant symmetric supercapacitor assembled with PW 12 @MIL-101/PPy-0.15 displays a sizable energy density of 20.7 Wh/kg at a power density of 277.6 W/kg. About 83.7 % of the pristine capacitance is still reserved after 2000 consecutive charges and discharges.