Asymmetric supercapacitors (ASCs) with aqueous electrolyte medium have recently become the focus of increasing research. For high performance ASCs, selection of cathode materials play a crucial role, and core-shell nanostructures are found to be a good choice. We successfully synthesized, ZnO@MnO core-shell nanofibers (NFs) by modification of high-aspect-ratio-electrospun ZnO NFs hydrothermally with MnO nanoflakes. High conductivity of the ZnO NFs and the exceptionally high pseudocapacitive nature of MnO nanoflakes coating delivered a specific capacitance of 907 Fg at 0.6 Ag for the core-shell NFs. A simple and cost-effective ASC construction was demonstrated with ZnO@MnO NFs as a battery-type cathode material and a commercial-quality activated carbon as a capacitor-type anode material. The fabricated device functioned very well in a voltage window of 0-2.0 V, and a red-LED was illuminated using a single-celled fabricated ASC device. It was found to deliver a maximum energy density of 17 Whkg and a power density of 6.5 kWkg with capacitance retention of 94% and Coulombic efficiency of 100%. The novel architecture of the ZnO@MnO core-shell nanofibrous material implies the importance of using simple design of fiber-based electrode material by mere changes of core and shell counterparts.

We report synthesis and electrochemical performance of silicon-based molecular precursor-derived ceramic (PDC)/carbon nanotube-embedded graphene self-supporting composite papers as Li-ion battery and supercapacitor electrodes.

No abstract

Chemists have attempted to minimize waste by designing new and more environmentally friendly methods for synthesizing catalysts. They produced an array of improved methodologies, including the use of locally available raw materials such as clay or modified clay instead of chemicals for catalyst preparation. The present study highlights the synthesis and characterization of hierarchical catalyst from locally available montmorillonite. The synthesised catalyst was characterized by, Powder X-ray diffraction, X-Ray Fluorescence (XRF), Forier Transform infrared (FT-IR) spectroscopy, N2 adsorption-desorption isotherms, Scanning electron microscopy (SEM), Thermo gravimetric analysis (TGA), for their crystal structure, surface analysis, morphology, thermal stability and catalytic performance. The synthesized catalyst designed to fit specific reaction for pharmaceutical preparation.