Enhanced capacitor effects in polyoxometalate/graphene nanohybrid materials: a synergetic approach to high performance energy storage

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作者：

K Kume，N Kawasaki，H Wang，T Yamada，H Yoshikawa，K Awaga

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摘要：

A synergetic combination of a chemical redox reaction and a physical capacitor effect in one electrochemical cell is a promising route to realize both high-energy and high-power-density energy storage. In the present work, we studied the electrochemical properties of a nanohybrid system of polyoxometalate (POM) and graphene (RGO), in which individual POM molecules are adsorbed on the RGO surfaces. The molecular cluster battery (MCB) in which the POM/RGO hybrid was adopted as a cathode active material exhibited a higher battery capacity than the POM/SWNT (single-walled carbon nanotube)-MCB and the microcrystal POM-MCB. The observed capacity for the POM/RGO-MCB was found to be much larger than the theoretical one, as calculated from the redox changes in POM, indicating a cooperative enhancement of the capacitor effects of RGO, induced by the POMs on the RGO surfaces.

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关键词：

Practical, Experimental/ adsorption electrochemical electrodes electrochemistry graphene nanocomposites organic-inorganic hybrid materials oxidation polymers reduction (chemical) secondary cells supercapacitors/ polyoxometalate-graphene nanohybrid materials high-performance energy storage chemical redox reaction physical capacitor effect electrochemical cell high-power-density energy storage electrochemical properties POM molecules adsorption molecular cluster battery cathode active material battery capacity single-walled carbon nanotube microcrystal POM-MCB C/ A8640N Storage in electrical energy A6146 Structure of solid clusters, nanoparticles, nanotubes and nanostructured materials A6845D Adsorption and desorption kinetics evaporation and condensation A8116 Methods of nanofabrication and processing A8230 Specific chemical reactions reaction mechanisms A8245 Electrochemistry and electrophoresis A8265M Sorption and accommodation coefficients (surface chemistry) A8630F Secondary cells