Doped Carbon Nanotubes Research Articles

Optical Properties of Single-walled Carbon Nanotubes

In this paper, a series of single-walled carbon nanotubes’ optical properties are researched by using the ABINIT software package. The results show that the dielectric function and absorption coefficient of carbon nanotubes are related to both their geometric structure and their electronic structure. This has a guiding role for the further research of the optical properties of doped carbon nanotubes, carbon nanotubes with defects, and carbon nanotube arrays.

Bi-Porphyrins MOF with confinement and ion-attracting effects in concert with RuO2-doped CNT as efficient electrocatalysts for HER in acidic and alkaline media

It is highly desirable and challenging to design efficient and stable hydrogen evolution reaction (HER) electrocatalysts in a variety of acidic and alkaline media. Here, a novel ternary catalyst has been proposed consisting of ruthenium dioxide doped carbon nanotubes (denoted as RuO2@CNT) wrapped in a multi-step strategy with a first synthesis of a bismuth metal porphyrin-based organic framework as co-catalyst (denoted as RuO2@CNT@MOF). The addition of CNT improves not only the conductivity of the electrocatalyst but also the distribution of the active RuO2 particles. Furthermore, the highly symmetrical conjugated structure of Bi-TCPP MOF facilitates both the adsorption of hydrogen ions and the generation of hydroxyl radicals (•OH). The Bi-TCPP MOF encapsulated in the outer layer of RuO2@CNT enhances the mechanical strength and creates the confinement effect, leading to the synthesis of RuO2@CNT@MOF as a HER electrocatalyst that exhibits excellent catalytic performance and acid and base resistance. In particular, low overpotentials of 13 mV and 50 mV can be achieved to provide current densities of 10 mA cm−2 in alkaline and acidic media, respectively. Significantly, this work provides new ideas for the careful design and development of MOFs as co-catalysts to improve the overall performance of materials in energy-related fields.

Internal doping of metallic carbon nanotubes for chemiresistive sensing of explosive molecules

Carbon nanotubes (CNTs) have been the focus of much chemical sensing research, typically employing a chemiresistive sensing mechanism. Their effective application in hazardous gas sensing has been hindered by a number of drawbacks, including: poor selectivity, irreversibility, temperature instability, and relatively high sensitivity to oxygen. All of these issues may be addressed by deploying metallic CNTs in a new configuration: nanotube sensor arrays internally doped by encapsulated species (halogens, alkali metals, interhalogens, and alkali metal halides) which p-dope or n-dope the pristine material. Such a sensor design offers: selectivity via the dissimilar response of the diversely doped tubes to various analytes, reversibility by establishing the fully cleaned CNT surface as a sensor reference state, temperature stability by encapsulation of the dopants, and doping-induced sensitivity to a range of analytes, including ammonia, nitrogen dioxide, and both nitramine and nitroaromatic explosives. Ab initio analysis suggests that internally doped metallic CNT sensor arrays can dramatically improve the performance of CNT based gas sensors, capitalizing on both the high mass specific surface area and the stable encapsulation features of one dimensional materials.

Ultrasonic-assisted synthesis of Ni based-layered double hydroxide doped carbon nanotube and its highly efficient in water oxidation reaction

Among the developed electrocatalysts, NiCr-layered double hydroxides (NiCr-LDH) are one of the most effective electrocatalytic materials for water oxidation. However, applications of such a kind of materials are practically limited due to their poor electric conductivity. In this work, the single-walled carbon nanotube (SWCNT) was doped to NiCr-LDH, and the LDH-based nanocomposites were synthesized using the one-step ultrasonic-assisted method. Physicochemical properties of the NiCr-LDH/SWCNT composites were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), field emission−scanning electron microscopy (FE−SEM), and linear sweep voltammetry (LSV). The NiCr-LDH/SWCNT composites were used as effective nanomaterials for oxygen evolution reaction (OER) at a near neutral medium. The LSV results confirm that the overpotential of the NiCr-LDH/SWCNT-0.006 sample decreased to about 120 mV at pH = 9.5, as compared with that of the NiCr-LDH or NiCr-LDH-SWCNT-0.006 (prepared by the two-step method) sample. The high oxygen evolution activity of NiCr-LDH/SWCNT-0.006 was associated with the co-presence of the homogeneously dispersed NiCr-LDH, good electrochemical activity, and high electrical conductivity. In addition, the as-prepared optimized NiCr-LDH/SWCNT electrocatalyst was highly stable for the OER reaction.

Effects of nematic liquid crystal doped with multi-walled carbon nanotube on electro-optic properties and electrostatic discharge immunity of liquid crystal display device

ABSTRACT Electrostatic discharge is a vexing problem in liquid crystal display device, which can cause abnormal display. Conventional solutions for liquid crystal doped with antistatic agent usually introduce additional impurity ions and increases the power consumption of liquid crystal display device. In this study, multi-walled carbon nanotube doped liquid crystal cells without obvious clusters are successfully fabricated. Comparing the electro-optic properties of undoped and doped cells, it is verified that doping does not negatively affect the liquid crystal cells with E7 host by measuring basic parameters such as relative permittivity, threshold voltage and response time. The liquid crystal cells are then tested using an electrostatic discharge generator to simulate the human-machine air discharge that occurs during actual operation. The immunity of the doped versus undoped cells is quantitatively compared in terms of the duration of so-called image sticking, it is found that the electrostatic discharge immunity of cell has a significant relationship with electrical conductivity. In addition, the relationship between the conductivity and relaxation time of image sticking is obtained by theory. It is determined that doping carbon nanotubes into E7 can effectively improve the electrostatic discharge immunity of liquid crystal display device without negatively affecting practical application.

Hydrogen storage studies of Co, Fe, Fe3C nanoparticles encapsulated nitrogen doped carbon nanotubes

AbstractThe most crucial part of the hydrogen economy is the development of a hydrogen storage material which will be cost effective and its hydrogen storage capacity meets US DOE target. This study is an attempt to develop an efficient hydrogen storage material from a simple, one step synthesis technique. Herein, we synthesize metal nanoparticles encapsulated (M = Co, Fe, Fe3C) nitrogen doped carbon nanotubes (M/NCNT) for the efficient hydrogen adsorption within temperature range of 25°C to 100°C and at pressures 5 to 18 bar. The phase, morphology, surface area, and composition of the encapsulated metal nanoparticles NCNT were confirmed by different characterization techniques. Fe/NCNT is observed to have the highest hydrogen storage capacity of 3.3 wt% at room temperature, ~16 bar pressure, and the highest isosteric heat of adsorption (Qst) of 13 kJmol−1, among all. B,N‐CNTs reported 0.35 wt% hydrogen storage capacity at ~16 bar H2 equilibrium pressure and room temperature. The large surface area, defects produced on the CNT due to N doping as well as the presence of metal nanoparticles both inside, on the CNTs which results in the spillover mechanism for the dissociation of the hydrogen molecules into atoms and its diffusion through carbon layers within the CNT, are the factors that contribute to the enhancement of hydrogen storage capacity in M/NCNT.

One-dimensional hierarchical ZnCo-NCNT/Mo2C nanostructure as a high-efficiency bifunctional catalyst for rechargeable Zn-air batteries

Herein, a catalyst precursor is prepared by depositing bimetallic zeolitic imidazolate frameworks (BMZIFs) on a polypyrrole (PPy)-coated MoO3 nanobelt (NB). Next, BMZIFs (ZIF-8/ZIF-67), PPy and MoO3 are calcined into Co nanoparticles (NPs) dotted/Zn, Co doped carbon, nitrogen doped carbon nanotube (NCNT) and Mo2C NPs at 800 °C, respectively, to produce a one-dimensional (1D) hierarchical nano-catalyst. The 1D nano-catalyst with porous surface, large specific area and abundant defects maximumly exposes the catalytic active sites. Furthermore, the entire encapsulation of Mo2C NPs by NCNTs effectively restrains their agglomeration during the pyrolysis, and volume change in electrochemical reaction. Moreover, the simultaneous immobilization of bimetallic ZIFs on PPy is more likely to form small-sized Zn/Co NPs on NCNT than single ZIF. Accordingly, the nano-catalyst exhibits a small ΔE value of 0.791 V and the Zn-air battery based on this catalyst achieves an excellent peak power density of 231.6 mW cm−2 at 5 mA cm−2, and a much higher energy round-trip efficiency than Pt/C + RuO2 in the long-term (400 h) cycling experiment. The excellent ORR/OER behaviors of the catalyst is mainly attributed to the synergy between CoN4-graphene and Mo2C, which is verified by both experimental and density function theory (DFT) calculation results.

LOCALIZED MICROMECHANICAL PROPERTIES OF FINE-PITCH SAC305 DOPED CARBON NANOTUBE SOLDER JOINTS

The addition of carbon nanotube (CNT) to the solder alloy has gained the attention due to its beneficially improve the mechanical properties of the solder alloy. Because of the miniaturization progress of electronic component, micromechanical properties of solder joint need to be focused instead of conventional mechanical properties. In this study, micromechanical properties, and deformation behaviour of SAC305 solder joints with the different CNT doping (weight percentage of 0.01, 0.02, 0.03 and 0.04) were investigated. Localized micromechanical properties included hardness, reduced modulus and stress exponent were determined via nanoindentation approach. Microstructural analysis was performed via optical microscope and field emission scanning microscope (FESEM). Doping of CNT in the SAC305 solder matrix changed the microstructure phase distribution. It was found that, doping of CNT, increase the near eutectic phase and decrease the primary b-Sn phase area. Furthermore, hardness values of SAC305 solder joint increased with increasing of CNT doping weight percentage. Hardness values of SAC305 solder joint increase about ~7 - 40% with the doping of CNT from 0.01 wt. % to 0.04 wt. %. However, localized reduced modulus and stress exponent show random values and no correlated trend with CNT doping were observed. Random values trend of stress exponent revealed that, SAC305 solder joint with the CNT doped involved the combination of deformation mechanism. This is due to the response of phase and CNT in the solder matrix to the localized indentation. In conclusion, a localized approach to hardness properties influenced by the CNT doping weight percentage.

Contribution of Multiwalled carbon nanotubes to dielectric and elastic properties in E7 nematic liquid crystal

In this article, electrical parameters, and elastic constants of nematic liquid crystal (NLC) contributed multiwalled carbon nanotubes (MCN) are presented by dielectric spectroscopy method. The effects of reorientation on the nematic liquid crystal by doping of multi-walled carbon nanotubes were investigated to reveal. Analyzes of dielectric strength Δε′(ω), absorption coefficient α, relaxation time τ, dielectric anisotropy Δε′V, dielectric anisotropy ratio γ, splay elastic constant K11, and cross-over angular frequency ωco of MCN contribution to E7 nematic liquid crystal with DC supply voltage are presented. Reorientation of elastic dipolar liquid crystal molecules was demonstrated by reducing the positive type (p type) dielectric anisotropy value in the broadband angular frequency range with the MCN contribution to the E7 coded nematic liquid crystal. The supply voltage applied to the NLC samples was observed to have nearly Debye-type relaxation mechanism in the host E7 LC structure, tending to switch to a Debye-type relaxation mechanism by MCN doping. Dipole effects were enhanced by doping of multi-walled carbon nanotubes in the orientation of elastic NLC molecules, and the relaxation time of host E7 NLC and doped MCN/E7 NLC decreased with increasing bias voltages. Cole-Cole analysis with different supply voltages, it has been seen that it turns into a new equivalent circuit depending on the MCN contribution.

New electrode material integrates silver nanoprisms with phosphorus-doped carbon nanotubes for forensic detection of nitrite

A screen-printed carbon electrode (SPCE) was modified with a nanohybrid of silver (Ag) nanoprisms and phosphorus (P)-doped carbon nanotubes (AgNPr@P-CNT). The modified SPCE was coupled with a simple, portable flow system to produce an efficient amperometric sensor for the detection of nitrite ion (NO2−). P-doped CNTs were prepared via a one-pot solvothermal method and the P-CNTs were decorated with Ag nanoprisms synthesized by a one-pot chemical reduction method. The as-prepared AgNPr@P-CNT nanohybrid was thoroughly characterized. Energy-dispersive x-ray (EDX) analysis, Fourier transform infra‐red (FTIR), and Raman spectroscopy results confirmed the successful doping of CNTs with P atoms. Transmission electron microscopy (TEM) revealed the decoration of P-CNTs with triangular Ag nanoprisms measuring 25 ± 7 nm. In the optimal condition, the flow injection-amperometric sensor based on the developed AgNPr@P-CNT/SPCE exhibited suitable electrocatalytic activity toward NO2− oxidation. As a result, NO2− was detected with high sensitivity (0.73 µA µM−1 cm−2), a wide linear range (0.010–4000 µM), and a low limit of detection (0.0032 µM). The proposed sensing system was successfully applied to detect NO2− in gunshot residue samples, achieving good recoveries. The advantages of the proposed AgNPr@P-CNT nanohybrid can be applied in other electrochemical sensing applications.

Fe/N co-doped hierarchically porous carbon on N-doped carbon nanotubes towards oxygen reduction reaction

Rational design of efficient and durable non-noble transition metal doped carbon-based oxygen reduction electrocatalysts is the key to reduce catalyst cost and optimize fuel cell performance. Herein, hierarchically porous Fe/N co-doped porous carbon on N doped carbon nanotubes (Fe/N-C@NCNTs) are prepared via the pyrolysis of Fe-doped ZIF-8 embedded on polypyrrole nanotubes (PNTs). The as-prepared Fe/N-C@NCNTs electrocatalyst exhibits the limit current density of 5.7 mA cm−2 and the half-wave potential of 0.84 V (vs. RHE), indicating the excellent oxygen reduction performance. Furthermore, the electrocatalytic activity of Fe/N-C@NCNTs is only reduced by 7% after 650 min of the stability test. The remarkable oxygen reduction performance is attributed to the synergistic effects of abundant Fe-Nx-C active sites, high graphitization degree and hierarchically porous structure of electrocatalyst.

Integrating the essence of metal organic framework-derived ZnCoTe–N–C/MoS2 cathode and ZnCo-NPS-N-CNT as anode for high-energy density hybrid supercapacitors

Transition bimetallic compounds are exploited as high-capacity electrode materials for supercapacitors due to their abundant electroactive sites and electrical conductivity. However, it remains grand challenge to construct supercapacitor devices that deliver high energy density. Here, we report an attractive one-stone-two-birds strategy to develop metal organic frameworks (MOFs) derived cathodes and anodes consisting of zinc cobalt telluride integrated nitrogen doped carbon (ZnCoTe–N–C) and zinc cobalt nanoparticles encased nitrogen doped carbon nanotubes (ZnCo-NPs-N-CNTs), respectively. Particularly, ZnCoTe–N–C cathode exhibited high specific capacity of 192.77 mA h g−1, which was further improved by the presence of hierarchical molybdenum disulfides (MoS2) nanosheets. Increased electrochemical active sites provided by MoS2 nanosheets energizes both the capacity and stability of the electrode. Consequently, the ZnCoTe–N–C/MoS2 electrodes showed a higher specific capacity of 342.55 mA h g−1 as well as excellent long-term stability. Besides, the ZnCo-NPs-N-CNTs demonstrated an initial capacity of 207.22 mA h g−1 and retained a high specific capacity even after 50 A g−1. The excellent electrochemical activity of the electrodes is attributed to the incorporation of redox rich bimetallic components and nitrogen rich carbon directly grown on the current collector, which reduces the dead volume and avoids volume expansion during charge discharge process. Finally, a hybrid asymmetric supercapacitor (HASCs) assembled using ZnCoTe–N–C/MoS2 and ZnCo-NPs-N-CNTs delivered a high specific energy density and power density maintaining 93.6% of its capacitance after 20,000 cycles. This study expands a way to construct a hybrid supercapacitor with well-designed structure and superior performance for clean energy storage technologies utilizing minimum resources.

Confinement of CoOx-CoP nanoparticles inside nitrogen doped CNTs: A low-cost ORR electrocatalyst

Non-noble metal containing catalysts for oxygen reduction reaction (ORR) are being targeted due to their low cost and availability. The rarity, high-cost, and self-poisoning of noble metals are the main drawbacks for the large-scale applications. Herein, a facile and simple synthetic strategy is adopted to prepare non-noble metal-based nitrogen doped carbon nanotubes (N-CNTs). The cobalt oxides (CoOx) nanoparticles are in-situ encapsulated inside these N-CNTs which are then treated with acid (HCl) and phosphidized to obtain CoOx-CoP/N-CNTs. High resolution transmission electron spectroscopy (HR-TEM) results reveal that the ends of N-CNTs are closed with nanoparticles. X-ray photoelectron spectroscopy (XPS) confirms the presence of cobalt oxide and cobalt phosphide nanoparticles. The catalyst CoOx-CoP/N-CNTs2 demonstrated Eonset and E1/2 of 0.96 V and 0.81 V, respectively in alkaline environment which is very much comparable to the state of art catalyst (20 wt% Pt/C). Acid treatment significantly enhances the electrocatalytic activity for ORR in comparison to material synthesized without prior treatment with acid. The catalyst exhibits excellent durability over 10,000 cycles and methanol tolerance to 0.5 M methanol addition. The enhanced ORR activity is attributed to synergistic effect of carbon matrix and encapsulated nanoparticles.

Integrated fabrication process with multiple optimized factors for high power density of IPMC actuator

ABSTRACT Ionic polymer-metal composites (IPMCs) are typical smart materials that are commonly used in bionic applications, including soft robots, bionic flapping aircraft, and bionic fish. However, their low output force seriously limits device performance. Stacking of multiple IPMC actuators to improve the overall performance of soft actuators is a strategy that is used in practical applications. Under the energy dissipation condition in the IPMC stacking structure, if each single IPMC in the structure has high power density, the structure will produce excellent performance with high efficiency that can greatly promote wider application of IPMC actuators. To meet this requirement, a method for fabrication process integration with multiple optimized factors was used to obtain IPMC materials in this paper. Carbon nanotube (CNT) doping, isopropyl alcohol-assisted plating, and hot pressing with a mesoscopic structural mold were selected as typical optimization methods for process integration and were initially investigated separately to determine the optimal process parameters. By combining the best process parameters in an integrated process, the IPMC treated by isopropyl alcohol-assisted plating and CNT doping process (No. AC7) showed excellent actuation performance and high work density (~9.71/12.36 gf, ~14.93/31.89 kJ/m3 under 3/4 VDC). The enhanced performance meets the requirements for practical bionic applications.

Rational construction of FeNi3/N doped carbon nanotubes for high-performance and reversible oxygen catalysis reaction for rechargeable Zn-air battery

Metal-based alloys encapsulated in nitrogen-doped carbon (alloy@NC) catalysts with high-efficiency and cost-effective are promising to solve the sluggish kinetics of the oxygen reduction/oxygen evolution reaction (ORR/OER) in Zn-air batteries (ZABs). Here, a novel FeNi3 alloy nanoparticles encapsulated by N-doped carbon graphene nanotubes (FeNi3@NC) catalyst with 0D/1D/3D multi-structure is synthesized through combining ligand-assisted and in-situ catalytic assembly strategy. The hybrid catalyst FeNi3@NC exhibited highly efficient ORR catalytic activity and stability. Impressively, the FeNi3@NC only required an overpotential of 291 mV to drive a current density of 10 mA cm−2, successfully demonstrating their excellent bifunctional catalytic activity. Moreover, the assembled rechargeable Zn-air battery based on FeNi3@NC air electrode exhibited high power density of 149.7 mW cm−2 and specific capacity of 658 mAh gZn-1, and long-term stability up to 280 h, outperforming most of the recently reported catalysts. Density functional theory (DFT) reveals that C atom adjacent to the pyridinic-N in FeNi3@NC act as the active sites for ORR/OER, since the alloying FeNi3 combined by pyridinic-N effectively break electroneutrality of the C atom, thereby accelerating the kinetics process of the ORR/OER. This work provides some constructive guidelines for fabricating alloy@NC catalysts with bifunctional catalytic activity and deeply demonstrates the applicability modulate the electronic configuration to construct high-performance rechargeable ZABs.

Recent advances in the energy harvesting device technology using hetero-atom doped carbon nanotubes

Carbon nanotubes, graphene, and fullerene are forms of carbon finding widespread applications in numerous fields such as energy storage devices such as batteries and fuel cells, cosmetics, nano-electronics, nano-pharmaceuticals, nano-biotechnology, military devices and equipment, construction, coatings, cutting tools, catalysis and many more. The huge technological advancements, globalization, and never seen industrialization can gain more momentum only with the ready availability of sufficient energy resources and their harvesting. Fossil fuels remained one of the most important primary fuels all over the world and now the shift is towards more use of non-renewable energy resources. At the end of the last century, Svante Arrenius firstly proposed the interconnection between the increased concentration of gases such as CO2 in the atmosphere and the rise in the average temperature through global warming on our planet. This effect gets pronounced effects in various other natural cycles too as observed through various natural events in the 21st century. There are several global warming gases, but the principal emission associated with this change is carbon dioxide. Due to such environmental issues, emphasis is on the use of non-conventional energy sources such as solar, wind, geothermal, ocean, etc. Besides such sources, extensive work is going on the use of fuel cells and modern battery technology using carbon nanotubes (SWCNTs and MWCNTs). Presently, various advanced batteries and fuel cells are being developed using CNTs on an Industrial scale. In the last decade, efforts are taken to control the optical and electronic properties of CNTs incorporating hetero-atom (N, P, Si, S, Al, Ni, etc.) as a dopant for desired structural functionalization. The recent advancements in the field of energy harvesting devices (batteries or fuel cells) using hetero-atom-doped CNTs have been discussed here.

Fabrication of N−doped carbon nanotube/carbon fiber dendritic composites with abundant interfaces for electromagnetic wave absorption

Three−dimensional (3D) hierarchical nano−microstructures have shown unprecedented physicochemical properties. However, it still remains great challenge to construct well−defined architectures with 3D hierarchical feature. Herein, we develop an electrospinning technique followed by a high−temperature carbonization process to fabricate N−doped carbon fibers (NCF) with N−doped carbon nanotubes (NCNTs) vertically grown on the surface of NCF using the Fe species as catalysts. In the 3D hierarchical structures, the Fe3C nanoparticles (NPs) are embedded within NCF matrix, while the Fe NPs are encapsulated within NCNT. Due to the unique structural feature, the as−prepared hierarchical structure exhibits excellent electromagnetic wave absorption performance with an absorption bandwidth of 4.0 GHz and a minimum reflection loss of −49.56 dB with a thickness as low as 1.50 mm. Experimental and theoretical studies indicate that the enhanced electromagnetic wave absorption performance of the hierarchical structure can be explained by the increased conduction loss induced by the introduction of metallic NPs and formation of 3D conductive networks, and the enhanced polarization loss caused by the additional interfaces and defects in the hierarchical structure. This work provides an efficient way to fabricate 3D architecture for high−efficiency electromagnetic wave absorption.

Defective layered NiFe double hydroxides anchored on self-supported CoNi-nitrogen doped carbon nanotube composite as advanced electrocatalyst for oxygen evolution reaction

Oxygen evolution reaction (OER) is an essential process during electrochemical water-splitting. Due to its sluggish kinetics, low cost and highly efficient catalyst is invariably desired to decrease its overpotential for large-scale application. However, the overpotential of most advanced OER electrocatalysts is still more than 200 mV at the current density of 10 mA cm−2. In this work, we constructed active layered NiFe double hydroxides with cation defects on self-supported three-dimensional (3D) CoNi nitrogen-doped carbon nanotube composite substrate as integrated OER catalyst. Strikingly, electrochemical measurements showed that the optimized sample exhibited outstanding OER activity with low overpotentials of 178 and 268 mV at the current densities of 10 and 100 mA cm−2 in alkaline environment, alongside a good durability. The excellent OER performance was ascribed to the strongly synergistic effect of intrinsically active NiFe double hydroxide layers with abundant cation vacancies and 3D carbon nanotube composite substrate with good conductivity and various functional moieties, thus facilitating the electrocatalytic kinetic.

Microstructure and corrosion behavior of HVAF-sprayed Fe-based composite coatings doped TiB2 and CNTs

Fe-based composite coating doped well-dispersed titanium boride (TiB2) and carbon nanotubes (CNTs) were successfully fabricated via high velocity air fuel (HVAF) spraying. The microstructure and corrosion behavior of Fe-based metallic, Fe-TiB2 cermet and Fe/(TiB2-CNTs) coatings were comparatively investigated. It is found that doping TiB2, especially further doping 2.5 vol% CNTs could remarkably render the coatings lower porosity, favorable microstructure, superior hydrophobicity and then enhanced corrosion resistance. Thanks to the densest microstructure and the formation of passive films, pitting instead of severe etch groove in TiB2-Fe interface inside splats and inter-splats was the main corrosion mechanism of the Fe/(TiB2-CNTs) coating.

Enhanced energy harvesting performances of flexible piezoelectric nanocomposite based on CNTs@PZT nanofibers network

Flexible organic/inorganic piezoelectric nanocomposites are highly demanded for flexible wearable electronic devices due to their excellent mechanical flexibility and high piezoelectric performance. However, the output performance of ceramic-polymer-based piezoelectric nanogenerators (PENGs) is restricted by the poor electrical conductivity of the organic matrix and the distinct discrepancy in mechanical strength between inorganic filler and organic matrix. Herein, we propose a flexible piezoelectric polymer nanocomposite based on CNTs@PZT nanofibers (NFs) network where the carbon nanotubes (CNTs) were introduced into the piezoelectric lead zirconate titanate (PZT) NFs to simultaneously improve the electrical conductivity and mechanical strength of nanocomposites. When subjected to a periodical bending deformation, the CNTs@PZT NFs network-based PENG with optimal addition of CNTs (0.6 wt%) generates a maximum electrical output up to ∼12.5 V and ∼80 nA cm−2 which is four times higher than that of PENGs without CNTs doping. An ultrahigh power density of 91.7 nW cm−2 is obtained with an external load resistance of 40 MΩ when pressed via a 10 N compressive force, and furthermore, the generated power could charge a capacitor and further light a commercial LED. This work may pave a new way for the development of high-output nanocomposite-type PENGs.