Three-dimensional Carbon Nanotube Networks Research Articles

Synergistic enhanced Zinc-ion battery performance achieving by atomic layer deposition of TiO2 on three-dimensional carbon nanotube network decorated Zn anode

Herein, we report a unique synergistic effect between carbon nanotube (CNT) network and atomic layer deposition (ALD) of TiO2, which not only enhances the ability to capture zinc ions but also suppresses Zn dendrite growth, resulting in uniform deposition of zinc ions during repeated cycles. The CNTs with luxuriant three-dimensional skeleton structure can provide plentiful deposition sites on Zn metal anode, which significantly reduces the nucleation overpotential and improves the reaction kinetics. Meanwhile, the TiO2 can repeatedly guide the uniform deposition of Zn owing to the excellent zincophilic. The deposition mechanism of zinc in the modified anode (TiO2CNT@Zn anode) is fully explained by comparing different carbon materials. The TiO2CNT@Zn anode shows a high Zn plating/stripping reversibility with an ultralow nucleation overpotential and achieves an ultralong lifespan over 2000 h with a voltage hysteresis of 22.5 mV compared to bare zinc (BZ) anode (63.7 mV) at a high current density of 5 mA cm−2. Moreover, the TiO2CNT@Zn anode maintains a highly stable Coulombic efficiency of 98.9% for more than 500 h. Moreover, the Zn-MnO2 battery with the TiO2CNT@Zn anode shows remarkably enhanced cycling stability.

Improved thermal conductivities of vertically aligned carbon nanotube arrays using three-dimensional carbon nanotube networks

Vertically aligned carbon nanotube (VACNT) arrays are considered promising thermal interface materials (TIM) due to their superior vertical thermal conductivity. However, the weak interaction between adjacent carbon nanotubes (CNT) leads to the change in orientation of the CNT during polymer infiltration. Therefore, the thermal conductivity of a CNT array/polymer composite does not reach the expected value. Simultaneously, the air gap between adjacent CNT hinders the in-plane heat transfer, and both of the above aspects significantly reduce the thermal conductivities of VACNT-based TIM. In this study, we proposed a novel three-dimensional CNT (3DCNT) network structure comprising VACNT crosslinked by randomly-oriented secondary CNT to provide several in-plane phonon paths and maintain the structural stability of the CNT arrays during polymer infiltration. The network structures formed by the secondary CNT were compared for two different growth times: 10 and 20 min. The 3DCNT network that grew for 20 min exhibited a denser network structure compared to the network that grew for 10 min. The vertical thermal conductivity and horizontal thermal conductivity of the 3DCNT20/Polydimethylsiloxane (3DCNT20/P) composite was 544.77% and 56.06% higher than those of the IVACNT/P composites, respectively.

CF4 Capture and Separation of CF4-SF6 and CF4-N2 Fluid Mixtures Using Selected Carbon Nanoporous Materials and Metal-Organic Frameworks: A Computational Study.

The adsorption of pure fluid carbon tetrafluoride and the separation of CF4–SF6 and CF4–N2 fluid mixtures using representative nanoporous materials have been investigated by employing Monte Carlo and molecular dynamics simulation techniques. The selected materials under study were the three-dimensional carbon nanotube networks, pillared graphene using carbon nanotube pillars, and the SIFSIX-2-Cu metal–organic framework. The selection of these materials was based on their previously reported efficiency to separate fluid SF6–N2 mixtures. The pressure dependence of the thermodynamic and kinetic separation selectivity for the CF4–SF6 and CF4–N2 fluid mixtures has therefore been investigated, to provide deeper insights into the molecular scale phenomena taking place in the investigated nanoporous materials. The results obtained have revealed that under near-ambient pressure conditions, the carbon-based nanoporous materials exhibit a higher gravimetric fluid uptake and thermodynamic separation selectivity. The SIFSIX-2-Cu material exhibits a slightly higher kinetic selectivity at ambient and high pressures.

Synergistic Enhanced Zinc-Ion Battery Performance Achieving by Atomic Layer Deposition of Tio2 on Three-Dimensional Carbon Nanotube Network Decorated Zn Anode

Synergistic Enhanced Zinc-Ion Battery Performance Achieving by Atomic Layer Deposition of Tio2 on Three-Dimensional Carbon Nanotube Network Decorated Zn Anode

The Impact of Ionic Liquid Loading in Three-Dimensional Carbon Nanotube Networks on the Separation of CO2/CH4 Fluid Mixtures: Insights from Molecular Simulations

The Impact of Ionic Liquid Loading in Three-Dimensional Carbon Nanotube Networks on the Separation of CO₂/CH₄ Fluid Mixtures: Insights from Molecular Simulations

Three-dimensional carbon nanotube networks from beta zeolite templates: Thermal stability and mechanical properties

Zeolite-templated carbons (ZTC) are structures synthesized via chemical vapor deposition of precursors inside sacrificial zeolites, with diverse applications. In spite of the interest in ZTC, little is known regarding their mechanical properties. Here, we investigate the thermal and mechanical behaviors of three-dimensional beta zeolite-templated carbon nanotube networks (BZCN). These networks are topologically generated by inserting carbon nanotubes (CNTs) into zeolite channels and connecting them using X-type junctions. We considered two cases, one with the tubes filling all zeolite channels (HD-BZCN) and the other with just partial filling (LD-BZCN). Fully atomistic reactive molecular dynamics (MD) simulations show that the networks exhibit high thermal stability (up to 1000 K). When compressed, the structures can withstand very large strains without fracturing (>50% for HD-BZCN and >70% for LD-BZCN). LD-BZCN can be stretched over 100% without fracturing.

MXene-derived three-dimensional carbon nanotube network encapsulate CoS2 nanoparticles as an anode material for solid-state sodium-ion batteries

Solid state sodium-ion batteries (SSIBs) are promising energy storage devices due to the advanced safety and abundant natural sodium sources.

Reliability Analysis of Carbon Nanotube-Based Nano-Truss Under Various Loading Conditions

Novel three-dimensional carbon nanotube networks have recently attracted significant interest due to their highly desirable material properties. In various potential applications, these structures may be subjected to various loading conditions. Furthermore, they are encountered with various inherent uncertainties which potentially could have a great effect on the mechanical behavior of these novel structures. The structural reliability framework provides a useful tool for considering the random nature of parameters in the analysis and design of new structures. Therefore, in this paper, the reliability analysis of a carbon nanotube-based nano-truss subjected to various loading conditions is investigated for the first time in the literature. The reliability analysis is conducted by the use of the first-order reliability method and Crude Monte Carlo approach. The results revealed that the nano-truss has larger reliability when subjected to uniaxial tension. This physically means that the performance of this new structure in the tension load is much better than that in shear load. This study provides a new perspective on understanding the mechanical behavior of carbon nanotube-based nano-truss.

High Strength Conductive Polyamide 6 Nanocomposites Reinforced by Prebuilt Three-Dimensional Carbon Nanotube Networks.

The rapidly growing fields of aerospace, energy, and electronic devices raise the demand for materials with ever-increasing mechanical properties and electrical and thermal conductivity. However, the combination of unusual high performance is difficult to attain. In this study, using prebuilt three-dimensional (3D) closely packed interconnected multiwalled carbon nanotube (MWNT) networks as a backbone for assembly of polymer matrix, a novel, green (solvent-free), and energy-saving method to prepare robust, highly electrical, and thermal conductive polyamide nanocomposites is reported. The as-prepared nanocomposites exhibit significant enhancements of 16 orders of magnitude in electrical conductivity and 505% in thermal conductivity, which mainly benefits from the contributions of closely packed 3D networks and conductive pathways of carbon nanotubes. In addition, even at a high MWNT loading of 25 wt %, the as-prepared nanocomposites still possess a high tensile strength of 99.4 MPa and Young's modulus of 5.3 GPa. The performance of the as-prepared nanocomposites exceeds that of most of the composites, which confirms the potential of the prebuilt MWNT network method for fabricating robust and highly conductive nanocomposites and the importance of good interconnectivity of nanofillers-nanofillers and nanofillers-matrix. The special fabrication method could open up a broad range of possibilities for aerospace, conducting elements, and structural nanomaterials, as well as electronic components with the requirements of heat dissipation, mechanical strength, thermal repair, corrosion resistance, and so on.

Thermal conductivity characterization of three dimensional carbon nanotube network using freestanding sensor-based 3ω technique

A novel three-dimensional (3D) carbon nanotube (CNT) network, composed of vertically aligned CNT array (primary CNT) bridged with randomly oriented secondary CNT, is synthesized in this work. We report the first data for the thermal properties of this new structure using freestanding sensor-based 3ω technique. Introducing freestanding sensor to conventional 3ω system enables the nondestructive characterization for samples with rough surfaces. The thermal conductivities of CNT films, as well as the contact resistance between the sensor and sample surfaces, are extracted numerically by a finite-element thermal model. The thermal conductivities of 3D CNT network under different array densities range from 9.3 to 19.8 W/mK. It is found that at lower CNT array density of 5.6 × 108/cm2, the growth of secondary CNT enhances the thermal conductivity of primary CNT array by 55.9%. This significant improvement in thermal conductivity can be attributed to the additional thermal pathway provided by the secondary CNTs in the primary CNT forest. However as the density of primary CNT array increases beyond 7.2 × 108/cm2, the growth of secondary CNTs on primary CNT forest reduces its thermal conductivity. This reduction in thermal conductivity can possibly be caused by the excessive thermal resistance from the CNT-CNT connection points within 3D CNT network.

Novel three-dimensional carbon nanotube networks as high performance thermal interface materials

Vertically aligned carbon nanotube (VACNT) arrays are considered as promising thermal interface materials (TIMs) due to their superior out-of-plane thermal conductivities. However the air gaps between adjacent CNTs within the CNT array hinder the in-plane heat transfer, thus significantly degrading the thermal performance of VACNT-based TIMs. To improve the in-plane thermal conduction of VACNT arrays, we propose a novel three dimensional CNT (3D CNT) network structure, where VACNTs are cross-linked by randomly-oriented secondary CNTs. Three different catalyst preparation methods for the secondary CNT growth are compared in terms of their ability to produce a dense network of secondary CNTs. The 3D CNT network grown using the chemical impregnation method shows a denser network structure, and thus is chosen for further thermal characterization. The temperature fields of the corresponding 3D CNT network under different heating powers are recorded using a 15 μm-resolution infrared thermal imaging system. The in-plane thermal conductivity is then derived from these fields using numerical fitting with a 3D heat diffusion model. We find that the in-plane thermal conductivity of the 3D CNT network is 5.40 ± 0.92 W/mK, at least 30 times higher than the thermal conductivity of the primary VACNT array used to grow the 3D CNT network.

Three-dimensional carbon nanotube networks enhanced sodium trimesic: a new anode material for sodium ion batteries and Na-storage mechanism revealed by ex situ studies

A new organic material (Na3TM) is proposed as an advanced anode for SIBs, and its Na-storage mechanism is ascertained.

Highly selective separation and adsorption-induced phase transition of SF6-N2 fluid mixtures in three-dimensional carbon nanotube networks

The separation of an equimolar SF6-N2 fluid mixture in a three-dimension porous carbon nanotube network has been investigated by means of classical molecular dynamics simulations at ambient conditions. The calculations performed have shown that the SF6 molecules are preferentially adsorbed over the nitrogen ones, yielding a high selectivity for sulfur hexafluoride. The adsorbed mixture is much denser than the bulk supercritical fluid, exhibiting a liquid-like behavior, which is reflected on the static structural, transport and dynamic properties of the confined mixture.

Applications of three-dimensional carbon nanotube networks.

In this paper, we show that it is possible to synthesize carbon-based three-dimensional networks by adding sulfur, as growth enhancer, during the synthesis process. The obtained material is self-supporting and consists of curved and interconnected carbon nanotubes and to lesser extent of carbon fibers. Studies on the microstructure indicate that the assembly presents a marked variability in the tube external diameter and in the inner structure. We study the relationship between the observed microscopic properties and some potential applications. In particular, we show that the porous nature of the network is directly responsible for the hydrophobic and the lipophilic behavior. Moreover, we used a cut piece of the produced carbon material as working electrode in a standard electrochemical cell and, thus, demonstrating the capability of the system to respond to incident light in the visible and near-ultraviolet region and to generate a photocurrent.

Carbon nanotube based flexible counter electrode for quasi-solid state dye sensitized solar cells

Low temperature fabrication of carbon nanotube based conductive composite polymer (CNT-CCP) film on conductive flexible substrate indium tin oxide coated polyethylene terephthalate film (ITO-PET) is developed as a low cost alternative to the Pt counter electrode especially for flexible quasi-solid state dye sensitized solar cells (DSSCs). The formation of three-dimensional carbon nanotube network provides the conductivity pathway which is improved with the carbon nanotube content and the film thickness increase. More importantly, the conductivity of CNT-CCP films greatly influences the performance of DSSCs. With high conductivity, good catalytic activity and especially the good consistence of the CNT-CCP with the polymer electrolyte, flexible CNT-CCP/ITO-PET counter electrode for the DSSC with the quasi-solid state composite polymer electrolyte exhibits performance of 4.24% (0.95Sun, AM1.5), which is 87% of the quasi-solid state DSSC with Pt counter electrode (4.87%). It indicates the CNT-CCP type counter electrode is promising for the flexible DSSCs.

A three-dimensional carbon nanotube network for water treatment

The bulk synthesis of freestanding carbon nanotube (CNT) frameworks is developed through a sulfur-addition strategy during an ambient-pressure chemical vapour deposition process, with ferrocene used as the catalyst precursor. This approach enhances the CNTs’ length and contorted morphology, which are the key features leading to the formation of the synthesized porous networks. We demonstrate that such a three-dimensional structure selectively uptakes from water a mass of toxic organic solvent (i.e. o-dichlorobenzene) about 3.5 times higher than that absorbed by individual CNTs. In addition, owing to the presence of highly defective nanostructures constituting them, our samples exhibit an oil-absorption capacity higher than that reported in the literature for similar CNT sponges.

Three-dimensional carbon nanotube networks with a supported nickel oxide nanonet for high-performance supercapacitors.

A three-dimensional porous carbon nanotube film with a supported NiO nanonet was prepared by simple electrophoretic deposition and hydrothermal synthesis, which could deliver a high specific capacitance of 1511 F g(-1) at a high discharge current of 50 A g(-1) due to the significantly improved transport of the electrolyte and electrons.

Pressure-dependent electrical conductivity of freestanding three-dimensional carbon nanotube network

The dependence of electrical conductivity on compression of a freestanding three-dimensional carbon nanotube (CNT) network is investigated. This macrostructure is made of mm-long and entangled CNTs, forming a random skeleton with open pores. The conductivity linearly increases with the applied compression. This behaviour is due to increase of percolating pathways—contacts among neighbouring CNTs—under loads that is highlighted by in situ scanning electron microscopy analysis. The network sustains compressions up to 75% and elastically recovers its morphology and conductivity during the release period. The repeatability coupled with the high mechanical properties makes the CNT network interesting for pressure-sensing applications.

Hierarchical gold micro-nanostructures based on three-dimensional networks of carbon nanotubes fabricated by using electrochemical deposition

Three-dimensional (3D) hierarchical gold electrodes were fabricated using suspended 3D networks of carbon nanotubes (CNTs) on Si pillar templates using electrochemical deposition (ECD) in KAu(CN)2 solutions. The Pt-coated networks of CNTs played an important role in providing electrical paths for ECD through discontinuous Pt layers, resulting in a vertically uniform deposition of gold on micropillars and 3D networks of CNTs connected with adjacent micropillars. The structural characteristics of the 3D hierarchical gold electrodes were superior, and their cyclic voltammograms exhibited higher peak currents and lower peak separations than those of a plain gold electrode.

Colloid-Assisted Self-Assembly of Robust, Three-Dimensional Networks of Carbon Nanotubes over Large Areas

Natural materials, such as bone and spider silk, possess remarkable properties as a result of sophisticated nanoscale structuring. They have inspired the design of synthetic materials whose structure at the nanoscale is carefully engineered or where nanoparticles, such as rods or wires, are self-assembled. Although much work has been done in recent years to create ordered structures using diblock copolymers and template-assisted assembly, no reports describe highly ordered, three-dimensional nanotube arrays within a polymeric material. There are only reports of two-dimensional network structures and structures on micrometer-size scales. Here, we describe an approach that uses plasticized colloidal particles as a template for the self-assembly of carbon nanotubes (CNTs) into ordered, three-dimensional networks. The nanocomposites can be strained by over 200% and still retain high conductivity when relaxed. The method is potentially general and so may find applications in areas such as sensing, photonics, and functional composites.