Examinando por Autor "Rana, Moumita"

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Composite Fabrics of Conformal MoS2 Grown on CNT Fibers: Tough Battery Anodes without Metals or Binders
(ACS, 2021-06-28) Rana, Moumita; Boaretto, Nicola; Mikhalchan, Anastasiia; Vila, María; Marcilla, Rebeca; Vilatela, Juan José
In the quest to increase battery performance, nanostructuring battery electrodes gives access to architectures with electrical conductivity and solid-state diffusion regimes not accessible with traditional electrodes based on aggregated spherical microparticles while often also contributing to the cyclability of otherwise unstable active materials. This work describes electrodes where the active material and current collector are formed as a single nanostructured composite network, consisting of macroscopic fabrics of carbon nanotube fibers covered with conformal MoS2 grown preferentially aligned over the graphitic layers, without a metallic current collector or any conductive or polymeric additives. The composite fabrics of CNTF/MoS2 retain high toughness and show out-of-plane electrical conductivity as high as 1.2 S/m, above the threshold to avoid electrical transport-limited performance of electrodes (1 S/m) and above that of control nanocomposite lithium-ion battery electrodes (0.1 S/m) produced from dispersed nanocarbons. Cycled against Li, they show specific capacity as high as 0.7 A h/g along with an appreciable rate capability and cycling stability in low (108% capacity retention after 50 cycles at 0.1 A/g) as well as high current density (89% capacity retention after 250 cycles at 1 A/g). The composite fabrics are flexible, with high tensile toughness up to 0.7 J/g, over two orders of magnitude higher than conventional electrodes or regular MoS2 materials, and full-electrode capacity above state-of-the-art at different current densities.
Transparent and flexible high-power supercapacitor based on carbon nanotube fibre aerogels
(Royal Society of Chemistry, 2020-08-28) Senokos, Evgeny; Rana, Moumita; Vila, María; Fernandez Cestay, Julio; Costa, Rubén; Marcilla, Rebeca; Vila, María
In this work, we report the fabrication of continuous transparent and flexible supercapacitors by depositing a CNT network onto a polymer electrolyte membrane directly from an aerogel of ultra-long CNTs produced floating in the gas phase. The supercapacitors show a combination of a power density of 1370 kW kg−1 at high transmittance (ca. 70%), and high electrochemical stability during extended cycling (>94% capacitance retention over 20 000 cycles) and against repeated 180° flexural deformation. They represent a significant enhancement of 1–3 orders of magnitude compared to prior state-of-the-art transparent supercapacitors based on graphene, CNTs, and rGO. These features mainly arise from the exceptionally long length of CNTs, which makes the material behave as a bulk conductor instead of an aspect ratio-limited percolating network, even for electrodes with >90% transparency. The electrical and capacitive figures-of-merit for the transparent conductor are FoMe = 2.7, and FoMc = 0.46 F S−1 cm−2 respectively.