A green asymmetric supercapacitor with high energy density has been developed using birnessite-type ultrathin porous MnO(2) nanoflowers (UBMNFs) as positive electrode and functional mesoporous carbon nanotubes (FMCNTs) as negative electrode in 1 M Na(2)SO(4) electrolyte. Both of the electrode materials possess excellent electrochemical performances, with high surface areas and narrow pore size ...

A new feeding concept for electrical transportation systems is presented, based on supercapacitive energy storage. Supercapacitors are new and powerful components for energy storage. Compared with batteries, the amount of energy they can store is low and does not allow a large vehicle autonomy. Because supercapacitors have the property to be re-loadable in a few seconds, a sequential supply sys...

A simple and scalable method has been developed to fabricate nanostructured MnO2-carbon nanotube (CNT)-sponge hybrid electrodes. A novel supercapacitor, henceforth referred to as "sponge supercapacitor", has been fabricated using these hybrid electrodes with remarkable performance. A specific capacitance of 1,230 F/g (based on the mass of MnO2) can be reached. Capacitors based on CNT-sponge sub...

Layered intercalation compounds NaxMnO2 (x 5 0.7 and 0.91) nanoflakes have been prepared directly through wet electrochemical process with Na ions intercalated into MnO2 interlayers spontaneously. The as-prepared NaxMnO2 nanoflake based supercapacitors exhibit faster ionic diffusion with enhanced redox peaks, tenfold-higher energy densities up to 110 Wh?kg and higher capacitances over 1000 F?g ...

Because of their low voltage level, supercapacitors need arrangement with series connection in order to obtain voltage levels from few dozen to few hundred of volts. As for batteries, devices have then to be defined to balance the voltages across each series connected components. This paper presents the problematic of voltage sharing in a series connection of supercapacitors. It is generally de...

Supercapacitors, based on fast ion transportation, are specialized to provide high power, long stability, and efficient energy storage using highly porous electrode materials. However, their low energy density excludes them from many potential applications that require both high energy density and high power density performances. Using a scalable nanoporous graphene synthesis method involving a...

Stretchability and compressibility of supercapacitors is an essential element of modern electronics, such as flexible, wearable devices. Widely used polyvinyl alcohol-based electrolytes are neither very stretchable nor compressible, which fundamentally limits the realization of supercapacitors with high stretchability and compressibility. A new electrolyte that is intrinsically super-stretchabl...

The use of supercapacitors as energy storage systems is evaluated in this work. Supercapacitors are compared with other technologies such as compressed air, pumped hydro, superconductors and flywheels. This paper is focused on medium scale energy storage systems (applied to 100 kW photovoltaic generation plants). The supercapacitor is studied in detail, presenting these device structures, how t...

Supercapacitors, as one of the energy storage devices, exhibit ultrahigh capacitance, high power density, and long cycle. High specific surface area, mechanical and chemical stability, and low cost are often required for supercapacitor materials. Graphene, as a new emerging carbon material, has attracted a lot of attention in energy storage field due to its intrinsic properties. Polymers are of...

Among the areas of research and development which take a big importance in the field of electrical energy production are the fuel cells and supercapacitors. In this paper, we present a multiagent structure for energy management in a hybrid electrical vehicle. Our simulation application is conceived and developed to share, in an intelligent and instantaneous way, the demand of the electric power...