No abstract

In this work, we report for the first time, the synthesis of several carbon nanotube (CNT)/polyaniline (PANI) nanocomposites obtained through interfacial polymerization, in which the resulting material is obtained directly as a transparent and freestanding film at the water−toluene interface. The films are obtained spontaneously with high stability and can be easily transferred with high optical quality to any kind of substrate or directly to a desirable device. Samples containing several CNT/PANI ratios have been prepared. The characterization of the resulting materials was carried out by FT-IR, UV−vis-NIR, and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, scanning and transmission electron microscopy, and conductivity measurements. The results indicate that the polymerization of aniline starts at the carbon nanotube walls, resulting in polymer-coated CNTs. A π−π interaction between the CNTs and the PANI is proposed. The formation of the self-standing films is discussed in terms of the stabilization of the water−toluene interface.

The synthesis and characterization of thin fi lms of polyaniline/carbon nanotubes nanocomposites is reported, as well as their utilization as transparent electrodes in ITO-free organic photovoltaic devices. These fi lms are generated by interfacial synthesis, which provides them with the unique ability to be deposited onto any substrate as transparent fi lms, thus enabling the production of fl exible solar cells using substrates like PET. Very high carbon nanotube loadings can be achieved using these fi lms without signifi cantly affecting their transparency ( ≈ 80-90% transmittance at 550 nm). Sheet resistances as low as 300 Ω / ᮀ are obtained using secondary polyaniline doping in the presence of carbon nanotubes. These fi lms present excellent mechanical stability, exhibiting no lack in performance after 100 bend cycles. Flexible and completely ITO-free organic photovoltaic devices are built using these fi lms as transparent electrodes, and high effi ciencies (up to 2.27%) are achieved.

An automated metal powder three-dimensional (3D) printing method for in situ synthesis of free-standing 3D graphene foams (GFs) was successfully modeled by manually placing a mixture of Ni and sucrose onto a platform and then using a commercial CO laser to convert the Ni/sucrose mixture into 3D GFs. The sucrose acted as the solid carbon source for graphene, and the sintered Ni metal acted as the catalyst and template for graphene growth. This simple and efficient method combines powder metallurgy templating with 3D printing techniques and enables direct in situ 3D printing of GFs with no high-temperature furnace or lengthy growth process required. The 3D printed GFs show high-porosity (∼99.3%), low-density (∼0.015g cm), high-quality, and multilayered graphene features. The GFs have an electrical conductivity of ∼8.7 S cm, a remarkable storage modulus of ∼11 kPa, and a high damping capacity of ∼0.06. These excellent physical properties of 3D printed GFs indicate potential applications in fields requiring rapid design and manufacturing of 3D carbon materials, for example, energy storage devices, damping materials, and sound absorption.

The drive for significant advancement in battery capacity and energy density inspired a revisit to the use of Li metal anodes. We report the use of a seamless graphene-carbon nanotube (GCNT) electrode to reversibly store Li metal with complete dendrite formation suppression. The GCNT-Li capacity of 3351 mAh g approaches that of bare Li metal (3861 mAh g), indicating the low contributing mass of GCNT, while yielding a practical areal capacity up to 4 mAh cm and cycle stability. A full battery based on GCNT-Li/sulfurized carbon (SC) is demonstrated with high energy density (752 Wh kg total electrodes, where total electrodes = GCNT-Li + SC + binder), high areal capacity (2 mAh cm), and cyclability (80% retention at >500 cycles) and is free of Li polysulfides and dendrites that would cause severe capacity fade.