Nanostructured manganese dioxides: Synthesis and properties as supercapacitor electrode materials

International audienceLow-cost layered manganese oxides with the rancieite structural type were prepared by reduction of KMnO4 or NaMnO4 in acidic aqueous medium, followed or not by successive proton- and alkali-ion-exchange reactions. Samples were characterized by X-ray diffraction, energy dispersive X-ray analysis, BET surface area measurements, thermal analyses and X-ray photoelectron spectroscopy. As a result of successive exchange steps, compounds with high surface area (reaching 200 m(2) g(-1)) can be obtained, and in the case of syntheses made with KMnO4, the alpha-MnO2 phase is formed. Capacitive properties of the synthesized materials were studied using potentiodynamic cycling in K2SO4. Correlations between the electrochemical and the physicochemical properties of the samples were investigated. The interesting conclusion is that the morphology and the size of the particles influence directly the capacitance, and that among the samples presenting the best morphology, the compounds derived from K-containing rancieite-type compounds (and containing alpha-MnO2) present a better cycleability

Aqueous suspensions of glass silicate dielectric powders for ink-jet printing applications

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Deposition and Drying of Inkjet Printed Dielectric Layers

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Inkjet Printing of Coplanar Wire-Patch Antenna on a Flexible Substrate

International audienceIn this paper, a novel Coplanar Wire-Patch (CWP) antenna for 2.5 GHz applications is presented. This antenna has been fabricated using inkjet-printing technology on a flexible, low-cost paper substrate using a simple, fast and cheap process compared to the photolithography technology. The design characteristics of the antenna are verified and the experimental measurements are successfully compared to the simulated ones

Potentialities of the ink-jet printing prototypind process for the fabrication of multilayer functional devices

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Inkjet Printing of Frequency Selective Surfaces on EBG Antenna Radome

International audienceThis paper presents a solution to bypass the cost and flatness problems of electromagnetic band gap antennas. More precisely, a process to design an electromagnetic band gap antenna using frequency selective surfaces will be detailed. This kind of antenna had been designed before, but the used substrate is expensive and thin. A low cost and thick substrate (Plexiglas and window glass) has been used here, on which are printed the frequency selective surfaces using an inkjet printer; a cheaper process than photolithography technology. This type of substrate can also be used to manufacture the antenna radome. Finally, to validate this new structure, a 20 dBi antenna working around 7.5 GHz has been conceived, fabricated and successfully measured

Design and fabrication of EBG and CWP antennas using inkjet printing technology

International audienceThis article presents a solution to bypass the cost and flatness problems for low-cost electronic devices which is the inkjet printing. This process allows the use of flexible substrate materials, such as paper or plastics, suitable for a real-to-real process. More precisely, the procedure to design an electromagnetic band gap antenna using frequency selective surfaces and coplanar wire-patch antenna for 2.5-GHz applications is detailed. This kind of antenna has been designed before, but the used substrate is expensive and thin. These antennas were fabricated using inkjet printing technology on a flexible, low-cost paper substrate using a simple, fast, and cheap process compared to the photolithography technology. The design characteristics of the antennas were verified and the experimental measurements were successfully compared to the simulated one

Inkjet-Printed mesoporous silica microdots as Biosensors

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Aqueous supercapacitors on conductive cotton

Wearable electronics offer the combined advantages of both electronics and fabrics. In this article, we report the fabrication of wearable supercapacitors using cotton fabric as an essential component. Carbon nanotubes are conformally coated onto the cotton fibers, leading to a highly electrically conductive interconnecting network. The porous carbon nanotube coating functions as both active material and current collector in the supercapacitor. Aqueous lithium sulfate is used as the electrolyte in the devices, because it presents no safety concerns for human use. The supercapacitor shows high specific capacitance (~70\u201380 F\ub7g\u20131 at 0.1 A\ub7g\u20131) and cycling stability (negligible decay after 35,000 cycles). The extremely simple design and fabrication process make it applicable for providing power in practical electronic devices