33,864 research outputs found
Monolithic Carbide-Derived Carbon Films for Micro-Supercapacitors
Microbatteries with dimensions of tens to hundreds of micrometers that are produced by
common microfabrication techniques are poised to provide integration of power sources onto
electronic devices, but they still suffer from poor cycle lifetime, as well as power and temperature
range of operation issues that are alleviated with the use of supercapacitors. There have been a
few reports on thin-film and other micro-supercapacitors, but they are either too thin to provide
sufficient energy or the technology is not scalable. By etching supercapacitor electrodes into
conductive titanium carbide substrates, we demonstrate that monolithic carbon films lead to a
volumetric capacity exceeding that of micro- and macroscale supercapacitors reported thus far,
by a factor of 2. This study also provides the framework for integration of high-performance
micro-supercapacitors onto a variety of devices
Monolithic Carbide-Derived Carbon Films for Micro-Supercapacitors
Microbatteries with dimensions of tens to hundreds of micrometers that are produced by common microfabrication techniques are poised to provide integration of power sources onto electronic devices, but they still suffer from poor cycle lifetime, as well as power and temperature range of operation issues that are alleviated with the use of supercapacitors. There have been a few reports on thin-film and other micro-supercapacitors, but they are either too thin to provide sufficient energy or the technology is not scalable. By etching supercapacitor electrodes into conductive titanium carbide substrates, we demonstrate that monolithic carbon films lead to a volumetric capacity exceeding that of micro- and macroscale supercapacitors reported thus far, by a factor of 2. This study also provides the framework for integration of high-performance micro-supercapacitors onto a variety of devices
Fabrication and characterization of smart fabric using energy storage fibres
Fibre supercapacitors were designed and manufactured using a dip-coating method. Their electrochemical properties were characterized using a VersaSTAT 3 workstation. Chinese ink with a fine dispersion of carbon and binder was coated as the electrode material. The specific capacitance per unit length of a copper fibre supercapacitor with the length of 41 cm reached 34.5 mF/cm. When this fibre supercapacitor was bent on rods with a diameter of 10.5 cm, the specific capacitance per length was 93% of the original value (without bending). It showed that these fibre supercapacitors have good flexibility and energy storage capacity. Furthermore, the fibre supercapacitor in the fabric showed the same capacitance before and after weaving.The European Union Seventh Framework Programme (FP7/2007â2013) under grant agreement no. [281063]
High power density electrodes for Carbon supercapacitor applications
This paper presents results obtained with 4 cm2 Carbon/Carbon supercapacitors cells in organic electrolyte. In the first approach, a surface treatment for Al current collector foil via the solâgel route has been used in order to decrease the Al/active material interface resistance.
Performances obtained with this original process are: a low equivalent series resistance (ESR) of 0.5 Ω cm2 and a specific capacitance of 95 F gâ1 of activated carbon. Then, supercapacitors assembled with treated Al foil and active material containing activated carbon/carbon nanotubes (CNTs) with different compositions have been studied. Galvanostatic cycling measurements show that when CNTs content increases, both ESR and specific capacitance are decreased. Fifteen percent appears to be a good compromise between stored energy and delivered power with an ESR of 0.4 Ω cm2 and a specific capacitance of 93 F gâ1 of carbonaceous active material. Finally, cells frequency behaviour has been characterized by Electrochemical Impedance Spectroscopy. The relaxation time constant of cells decreases when the CNTs content increases. For 15% of CNTs, the time constant is about 30% lower as compared to a cell using pure
activated carbon-based electrodes leading to a higher delivered power
Production of carbon nanotubes by PECVD and their applications to supercapacitors
MĂ ster en NanociĂšncia i NanotecnologiaPlasma enhanced chemical vapor deposition (PECVD) is a versatile technique to obtain vertically dense-aligned carbon nanotubes (CNTs) at lower temperatures than chemical vapor deposition (CVD). In this work, we used magnetron sputtering to deposit iron layer as a catalyst on silicon wafers. After that, radio frequency (rf) assisted PECVD reactor was used to grow CNTs. They were treated with water plasma and finally covered by MnO2 as dielectric layer in order to use CNTs as electrode for supercapacitors. Optimization of annealing time, reaction time and temperature, water plasma time and MnO2 deposition time were performed to find appropriate conditions to improve the characteristics of supercapacitors. SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), AFM (Atomic Force Microscopy) and Raman spectroscopy were used to characterize obtained electrodes
Charge storage mechanism in nanoporous carbons and its consequence for electrical double layer capacitors
Electrochemical capacitors, also known as supercapacitors, are energy storage devices that fill the gap between batteries and dielectric capacitors. Thanks to their unique
features, they have a key role to play in energy storage and harvesting, acting as a complement to or even a replacement of batteries which has already been achieved in
various applications. One of the challenges in the supercapacitor area is to increase their energy density. Some recent discoveries regarding ion adsorption in microporous carbon exhibiting pores in the nanometre range can help in designing the next generation of high-energy-density supercapacitors
- âŠ