Electric field-modulated non-ohmic behavior of carbon nanotube fibers in polar liquids.

We report a previously unseen non-ohmic effect in which the resistivity of carbon nanotube fibers immersed in polar liquids is modulated by the applied electric field. This behavior depends on the surface energy, dielectric constant, and viscosity of the immersion media. Supported by synchrotron SAXS and impedance spectroscopy, we propose a model in which the gap distance, and thus the conductance, of capacitive interbundle junctions is controlled by the applied field.JT acknowledges generous financial support from: The Cambridge Commonwealth European and International Trust, CONACyT (Mexico), Dyson Ltd, and Pembroke College Cambridge. JJV acknowledges support from MINECO (Spain) and FP7-People-Marie Curie Action-CIG.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/nn5030835

Attachment of transition metal nanoparticles on nitrogen doped carbon nanotubes (MWNTs-CNx) and their further reactions.

Tesis (Maestría en Nanociencias y Nanotecnología)"The MWNTs-CNx exhibit important electronic and mechanical properties, that together with its small diameter, make them attractive for sensors production, substances specific filters and as field electrodes. Due to their structure, the MWNTs-CNx could also play an important role as substrates for the deposition of transition metal nanoparticles that allow to develop new catalysts. Thereby, the possibility of depositing some of this metals on MWNTs-CNx by a simple method, that does not involve oxidizing treatments in the nitrogen-doped carbon nanotubes, would enable to take advantages of their other properties. The results obtained from the use of the MWNTs-CNx as substrates for the transition metal nanoparticles deposits are presented in this work. At first stage, it was achieved an iron (Fe) deposit on the MWNTs-CNx, that by subsequent treatments produced a new type of hybrid structure composed by N-doped and undoped carbon nanotubes. Furthermore, are discussed the platinum (Pt) nanoparticles deposits that were also obtained in surface of MWNTs-CNx. Later, the morphological changes observed in the MWNTs-CNx by their electrochemical treatment or by the adding of titanium (Ti) during their synthesis by chemical vapor deposition (CVD) are explained. Finally, the feasibility of achieving silicon (Si) nanoparticles deposits on the surface of MWNTs-CNx by potentiometric techniques is also depicted.

Elastomeric and dynamic MnO2/CNT core-shell structure coiled yarn supercapacitor

Reversibly deformable and highly performing solid-state yarn supercapacitors are obtained using MnO2-deposited microcoiled yarn electrodes. The core(CNT)-shell(MnO2)-structured coiled electrodes achieve high stretchability (37.5%) without the help of elastomeric substrates, minimizing the size of the supercapacitors. Therefore, high specific capacitances of 34.6 F cm−3, 61.25 mF cm−2, and 2.72 mF cm−1 are achieved for coiled supercapacitors without impairing mechanical stretchability or electrochemical cyclability

Improvement of system capacitance via weavable superelastic biscrolled yarn supercapacitors

Yarn-based supercapacitors having improved performance are needed for existing and emerging wearable applications. Here, we report weavable carbon nanotube yarn supercapacitors having high performance because of high loadings of rapidly accessible charge storage particles (above 90 wt% MnO2). The yarn electrodes are made by a biscrolling process that traps host MnO2 nanoparticles within the galleries of helically scrolled carbon nanotube sheets, which provide strength and electrical conductivity. Despite the high loading of brittle metal oxide particles, the biscrolled solid-state yarn supercapacitors are flexible and can be made elastically stretchable (up to 30% strain) by over-twisting to produce yarn coiling. The maximum areal capacitance of the yarn electrodes were up to 100 times higher than for previously reported fibres or yarn supercapacitors. Similarly, the energy density of complete, solid-state supercapacitors made from biscrolled yarn electrodes with gel electrolyte coating were significantly higher than for previously reported fibre or yarn supercapacitors

Woven-yarn thermoelectric textiles

The fabrication and characterization of highly flexible textiles are reported. These textiles can harvest thermal energy from temperature gradients in the desirable through-thickness direction. The tiger yarns containing n- and p-type segments are woven to provide textiles containing n-p junctions. A high power output of up to 8.6 W m−2 is obtained for a temperature difference of 200 °C

Additive functionalization and embroidery for manufacturing wearable and washable textile supercapacitors

202307 bcwhAccepted ManuscriptRGCPublishe