Incorporation Of Multi-walled Carbon Nanotubes Research Articles

Enhancing Performance and Stability of High-Temperature Proton Exchange Membranes through Multiwalled Carbon Nanotube Incorporation into Self-Cross-Linked Fluorenone-Containing Polybenzimidazole.

Addressing critical challenges in enhancing the oxidative stability and proton conductivity of high-temperature proton exchange membranes (HT-PEMs) is pivotal for their commercial viability. This study uncovers the significant capacity of multiwalled carbon nanotubes (MWNTs) to absorb a substantial amount of phosphoric acid (PA). The investigation focuses on incorporating long-range ordered hollow MWNTs into self-cross-linked fluorenone-containing polybenzimidazole (FPBI) membranes. The absorbed PA within MWNTs and FPBI forms dense PA networks within the membrane, effectively enhancing the proton conductivity. Moreover, the exceptional inertness of MWNTs plays a vital role in reinforcing the oxidation resistance of the composite membranes. The proton conductivity of the 1.5% CNT-FPBI membrane is measured at 0.0817 S cm-1 at 160 °C. Under anhydrous conditions at the same temperature, the power density of the 1.5% CNT-FPBI membrane reaches 831.3 mW cm-2. Notably, the power density remains stable even after 200 h of oxidation testing and 250 h of operational stability in a single cell. The achieved power density and long-term stability of the 1.5% CNT-FPBI membrane surpass the recently reported results. This study introduces a straightforward approach for the systematic design of high-performance and robust composite HT-PEMs for fuel cells.

Confined Water Dynamics in the Scaffolds of Polylactic Acid.

Resorbable polylactic acid (PLA) ultrathin fibers have been applied as scaffolds for tissue engineering applications due to their micro- and nanoporous structure that favor cell adhesion, besides inducing cell proliferation and upregulating gene expression related to tissue regeneration. Incorporation of multiwalled carbon nanotubes into PLA fibers has been reported to increase the mechanical properties of the scaffold, making them even more suitable for tissue engineering applications. Ideally, scaffolds should be degraded simultaneously with tissue growth. Hydration and swelling are factors related to scaffold degradation. Hydration would negatively impact the mechanical properties since PLA shows hydrolytic degradation. Water absorption critically affects the catalysis and allowance of the hydrolysis reactions. Moreover, either mass transport and chemical reactions are influenced by confined water, which is an unexplored subject for PLA micro- and nanoporous fibers. Here, we probe and investigate confined water onto highly porous PLA microfibers containing few amounts of incorporated carbon nanotubes by Fourier transform infrared (FTIR) spectroscopy. A hydrostatic pressure was applied to the fibers to enhance the intermolecular interactions between water molecules and C=O groups from polyester bonds, which were evaluated over the wavenumber between 1600 and 2000 cm-1. The analysis of temperature dependence of FTIR spectra indicated the presence of confined water which is characterized by a non-Arrhenius to Arrhenius crossover at T0 = 190 K for 1716 and 1817 cm-1 carbonyl bands of PLA. These bands are sensitive to a hydrogen bond network of confined water. The relevance of our finding relies on the challenge detecting confined water in hydrophobic cavities as in the PLA one. To the best of our knowledge, we present the first report referring the presence of confined water in a hydrophobic scaffold as PLA for tissue engineering. Our findings can provide new opportunities to understand the role of confined water in tissue engineering applications. For instance, we argue that PLA degradation may be affected the most by confined water. PLA degradation involves hydrolytic and enzymatic degradation reactions, which can both be sensitive to changes in water properties.

Enhanced mechanical performance and damping behavior of CFRP composites through exfoliated MWCNT functionalization

In evaluating high-performance multiwall carbon nanotube (MWCNT) based carbon fiber composites, effective chemical functionalization of fillers for sufficient exfoliation and precise interface interactions with resin matrix are challenging to attain due to significant interlayer cohesive energy and inactive surfaces of composites. Herein, we demonstrate an effective way to produce carbon fiber-reinforced polymer (CFRP) composite with amended interfacial characteristics via incorporation of MWCNT through oxidation followed by silane functionalization with their exfoliation levels (0/48/60/72 h). The surface functional elements, morphological changes, elemental groups, quantitative information, and thermal degradation of silane functionalized MWCNTs were characterized by FESEM/HR-TEM, XRD, UV, and TG-DTA analysis, respectively. The influence of silane functionalized MWCNT reinforcement on CFRP's mechanical properties were examined using tensile, flexural, ILSS, and damping behavior was analyzed through impulse excitation technique (IET). The resulting silane-modified MWCNTs with 60 h oxidation (OAC-60) infused CFRP demonstrated significant enhancement in flexural strength (73.8%), tensile strength (58.2%), interlaminar shear strength (28.5%) compared to pure-CFRP.

Growth of MAPbI3 perovskite films on MWCNT-modified TiO2 thin films for solar cell applications

In this work, we have modified titanium dioxide (TiO2) films by incorporating multi-walled carbon nanotubes (MWCNTs) in TiO2-sol. TiO2 and MWCNT-modified TiO2 thin films have been prepared via solution processing spin coating route. Further, the structural, optical, and surface morphology of methyl ammonium lead iodide (MAPbI3) films have been studied onto pristine TiO2 and MWCNT-modified TiO2 films. We extensively analyze how different MWCNT concentrations impact the TiO2 and perovskite film structure, optoelectronic properties, and surface characteristics. The findings highlight that the MAPbI3 films maintain a tetragonal structure with enhanced crystallinity compact and smooth surface morphology in MWCNT-modified TiO2/MAPbI3 films. Besides this, enhanced optical absorbance in MAPbI3 films have also been observed on perovskite films fabricated onto MWCNT-modified TiO2 films with enlarged grains and a red shift in optical band gap has been observed for MWCNT-modified TiO2 films and MWCNT-modified TiO2/ MAPbI3 films. Further, various critical electrical parameters such as charge carrier concentration, Hall mobility, sheet resistance, and resistivity have been investigated to understand the effects of the incorporation of MWCNT on TiO2 films. The value of carrier concentration enhances from 3.76 × 1024 cm−3 to 6.39 × 1024 cm−3 on incorporation of MWCNT in TiO2 films. Furthermore, an enhancement in crystallinity, optical absorbance, and grain size has been observed in perovskite films fabricated onto TiO2/MWCNT films. Thus, TiO2 modification with MWCNT can tune the optical and charge transport properties of charge-transporting layer TiO2 films for perovskite photovoltaics and other optoelectronic devices.

Efficient electromagnetic interference shielding performance of poly(amide imide)/MWCNT‐based nanocomposites

AbstractThe establishment of conducting network in a polymer matrix is essential for the improvement in electrical conductivity and electromagnetic interference (EMI) shielding performance. Here, we report the fabrication of nanocomposites comprising polyamideimide and multiwalled carbon nanotubes (MWCNTs) (from 0.5 to 5.0 wt%). The effect of MWCNTs on electrical conductivity, morphology, and EMI shielding behavior has been examined. The morphology of nanocomposites was investigated by scanning electron microscope and x‐ray diffraction, which confirms the uniform dispersion of MWCNTs in the matrix. The electrical conductivity increases from 1.4 × 10−12 to 0.145 × 10−4 S/cm by the inclusion of MWCNTs. The composite PACNT‐5 exhibits a good EMI shielding efficiency of −17 dB in the X‐band region by employing only 5.0 wt% of MWCNTs. The incorporation of MWCNTs formed an interconnected conducting network, which boost the transferability of electrons or charge carriers. This work demonstrates a feasible, simple, and effective strategy for the fabrication of potential PAI/MWCNT composites for highly efficient EMI shielding materials.

Effectiveness of multi‐walled carbon nanotube on the improvement of tensile, flexural, and low‐velocity impact properties of hybrid Kevlar/carbon fiber reinforced epoxy‐based composites

AbstractIn this study, the effects of hybridizing carbon fibers with Kevlar fibers and incorporating multiwalled carbon nanotube (MWCNT) particles on low‐velocity impact, tensile, and flexural performance were evaluated experimentally. A manual lay‐up procedure followed by vacuum bag molding was used to construct hybrid composites (carbon and Kevlar) with and without MWCNTs, as well as hybrid composites with varying MWCNT weight ratios of carbon and Kevlar fiber reinforcements. When 0.1 wt% of MWCNT was added to the epoxy to enhance absorbed energy and peak load, the maximum improvements observed were 31% and 28%, respectively. The addition of MWCNTs by 0.5 wt% to the epoxy enhanced the flexural strength and flexural modulus by 66% and 41%, and by 5% with 0.1 wt% and 12.3% with 0.5 wt% MWCNT for tensile strength and tensile modulus, respectively. These improvements were observed in both tensile strength and tensile modulus. As for (C5K10C5), the maximum improvements in absorbed energy and peak load were observed to be 11.2% and 31%, respectively, corresponding to a 0.1 wt% MWCNT addition, whereas the maximum improvement in flexural strength and flexural modulus was 12.28% and 44%, respectively, with a 0.1 wt% MWCNT. These improvements in mechanical properties are primarily attributed to the enhanced stress transfer properties from fibers and nanoparticles to the matrix. This enhancement is a result of the strong interfacial interactions between epoxy and MWCNT nanoparticles.Highlights MWCNT inclusion effects on mechanical properties of carbon/Kevlar hybrid composites. MWCNT inclusion effects on low‐velocity impact properties of Carbon/Kevlar hybrid composites. The effects of Kevlar and carbon stacking sequence with MWCNT incorporation were investigated.

Evaluation of mechanical and erosive wear properties of hybrid nano composites basalt/E-glass fiber + MWCNTs/SiO2

The extensive study conducted has revealed that the mechanical and other characteristics of hybrid composites are greatly influenced by several aspects, such as the kind of fibre reinforcement, nanofillers, matrix materials, and the manufacturing methods employed. In the context of structural applications, the incorporation of Multi-wall Carbon Nanotubes (MWCNTs) as fillers in E-Glass fibres had a significant impact on the rapid alteration of mechanical properties, particularly strength, in the composites. This study aimed to create hybrid nanocomposites by including multi-walled carbon nanotubes (MWCNTs) and silicon dioxide (SiO2) as filler materials, Basalt/E-glass as fibres, and epoxy with hardener as the matrix. This study utilises statistical methods, specifically the Taguchi L16 Orthogonal Array (OA), to analyse the impact of various operating factors. The parameters selected for this study include MWCNTs/SiO2 fillers at varying weight percentages (0 %, 1 %, 2.9 %, and 3 %), an epoxy matrix with decreasing weight percentages (40 %, 39 %, 38 %, and 37 %), compression pressures ranging from 5 MPa to 35 MPa, and moulding temperatures ranging from 40 °C to 100 °C. The mechanical parameters being examined are the tensile strength and erosive wear. The utilisation of the hand layup and compression moulding technique achieved the development of these composites. By optimising the moulding temperature, significant improvements were achieved in the tensile strength, which reached 184.38 MPa. Similarly, reducing the percentage of fillers resulted in a substantial decrease in erosive wear, with a value of 95.06 mg/kg.

BIOCOMPATIBLE ELASTIC POLYMER NANOCOMPOSITES BASED ON MULTIWALLED CARBON NANOTUBES FOR APPLICATION IN CARDIOVASCULAR SURGERY

HighlightsThe incorporation of multi-walled carbon nanotubes into the structure of the poly(styrene-block-isobutylene-block-styrene) polymer matrix leads to an increase in the tensile strength and Young's modulus of the nanocomposites. The resulting nanocomposites retain high biocompatibility and can be used as elements of implanted cardiovascular products. AbstractAim. To synthesize and modify poly(styrene-block-isobutylene-block-styrene) (SIBS) with two types of multi-walled carbon nanotubes (MWCNTs) in different concentrations to improve its mechanical properties.Methods. SIBS was synthesized by controlled cationic polymerization. Polymer nanocomposites were prepared using ultrasonic dispersion followed by casting films from a polymer solution. The resulting nanocomposite films were subjected to mechanical tests under uniaxial tensile conditions. Tensile strength, elastic-strain properties, and plastic deformation under cyclic loading were assessed. The structure of the nanocomposites was analyzed by scanning electron microscopy. The hydrophilicity of the surface of the materials was studied by measuring the contact angle with water. The cytotoxicity of the resulting polymer films was assessed by the viability and metabolic activity of endothelial cells cultured on the surface of the nanocomposites.Results. Polymer nanocomposites with a uniform distribution of MWCNTs in the polymer matrix were obtained. SIBS films modified with 1% MWCNTs with a diameter of 50–90 nm showed an increase in tensile strength by 16.4% compared to SIBS polymer. Increasing the concentration of MWCNTs to 8% led to a decrease in the strength of polymer materials by 19,6%. The inclusion of nanoparticles into the polymer matrix significantly increased the Young's modulus of the studied polymers with a MWCNT content above 4%. With an increase in the content of MWCNTs in the nanocomposites, an increase in hydrophilicity was also observed, while the cytotoxicity of the samples towards endothelial cells was not noted.Conclusion. Nanocomposites based on SIBS and MWCNTs, due to their high strength and biocompatibility, can become a promising material for the development of various medical products, in particular prosthetic heart valves.

Study on the Properties of Multi-Walled Carbon Nanotubes (MWCNTs)/Polypropylene Fiber (PP Fiber) Cement-Based Materials.

In order to improve the mechanical properties and durability of cement-based materials, a certain amount of multi-walled carbon nanotubes (MWCNTs) and polypropylene fiber (PP fiber) were incorporated into cement-based materials. The mechanical properties of the multi-walled carbon nanotubes/polypropylene fiber cement-based materials were evaluated using flexural strength tests, compressive strength tests, and splitting tensile tests. The effects of multi-walled carbon nanotubes and polypropylene fiber on the durability of cement-based materials were studied using drying shrinkage tests and freeze-thaw cycle tests. The effects of the multi-walled carbon nanotubes and polypropylene fibers on the microstructure and pore structure of the cement-based materials were compared and analyzed using scanning electron microscopy and mercury intrusion tests. The results showed that the mechanical properties and durability of cement-based materials can be significantly improved when the content of multi-walled carbon nanotubes is 0.1-0.15%. The compressive strength can be increased by 9.5% and the mass loss rate is reduced by 27.9%. Polypropylene fiber has little effect on the compressive strength of the cement-based materials, but it significantly enhances the toughness of the cement-based materials. When its content is 0.2-0.3%, it has the best effect on improving the mechanical properties and durability of the cement-based materials. The flexural strength is increased by 19.1%, and the dry shrinkage rate and water loss rate are reduced by 14.3% and 16.1%, respectively. The three-dimensional network structure formed by the polypropylene fiber in the composite material plays a role in toughening and cracking resistance, but it has a certain negative impact on the pore structure of the composite material. The incorporation of multi-walled carbon nanotubes can improve the bonding performance of the polypropylene fiber and cement matrix, make up for the internal defects caused by the polypropylene fiber, and reduce the number of harmful holes and multiple harmful holes so that the cement-based composite material not only has a significant increase in toughness but also has a denser internal structure.

Effect of Coarse Aggregate and Multi-Wall Carbon Nanotubes on Heat Generation of Concrete

Many researchers are developing heating construction materials to remove black ice from roads, addressing the scientific challenges associated with this issue. The use of carbon-based nanomaterials in concrete is of great interest due to the excellent electrical and thermal conductivity of this material. In this study, the incorporation of multi-walled carbon nanotubes (MWCNTs) into concrete compositions results in the formation of MWCNT bridge networks. MWCNTs exhibit a low specific heat and possess the ability to promptly generate raised temperatures with minimal power input. This characteristic has the potential to induce temperature variations in concrete. The heat generation test parameters for MWCNT concrete included the mixing concentration of the MWCNTs, the mixing ratio of coarse aggregate, the water/cement (W/C) ratio, and the presence or absence of superplasticizers. The heating performance of concrete was found to improve as the mixing concentration of the MWCNTs increased, while a heating performance decrease was observed as the mixing ratio of coarse aggregate increased, owing to the reduced dispersibility of the MWCNTs. Conversely, the heating performance improved when the W/C ratio increased due to the enhanced dispersibility of the MWCNTs. Moreover, superplasticizers assist in dispersing MWCNTs, thereby improving the heating performance. Additionally, field emission scanning electron microscopy revealed that MWCNTs form a bridge network between the cement hydrates. As a result of this study, the maximum temperature variation of concrete mixed with MWCNTs was up to 73.6 °C. Therefore, by mixing MWCNT aqueous solutions with concrete and using an appropriate W/C ratio and superplasticizer, a new construction material capable of enhanced heating performance was developed.

Augmenting the mechanical performance of three‐dimensional woven composites by the synergistic effect of fabric architecture and interfacial interaction of carbon nanotubes

AbstractThree‐dimensional (3D) woven fabrics offer many advantages over planar woven fabrics for composite applications. Because of the complex structure of 3D woven fabrics, an in‐depth investigation is needed to understand the effects of fabric architecture and nanofillers on the mechanical and failure behavior of 3D woven composites. The present study investigates the effect of 3D woven ultrahigh‐molecular‐weight polyethylene (UHMWPE) orthogonal fabric architecture, with or without nanofillers, on the mechanical properties of composites. 3D woven orthogonal fabrics with varying proportions of stuffer‐to‐binder (S/B) yarns were manufactured and reinforced with an epoxy (EP) matrix. Multiwalled carbon nanotubes (MWCNTs) were infused as nanofillers to improve the interaction between the UHMWPE fabric and the EP matrix. 3D woven composite having an S/B ratio of 2:1 showed the maximum tensile strength and toughness. On the other hand, 3D woven composite with an S/B ratio of 4:1 showed higher flexural strength and impact resistance. The failure mechanism was also studied by examining the fractured surfaces of composites, which revealed matrix cracking, fiber pullout, predominant binder yarn failure, and yarn slippage. From this study, it is understood that for 3D fabric reinforcement, a balance between structural integrity and load‐bearing capacity of yarns is decisive, whereas for the matrix, the incorporation of MWCNTs is found to be advantageous.Highlights The role of structure of 3D woven orthogonal fabric on the mechanical behaviour of the UHMWPE‐epoxy composite is investigated. The addition of functionalized MWCNTs improves the tensile, flexural, and impact properties. The decisive role of the ratio of stuffer‐to‐binder yarns is established. Matrix cracking, debonding, and yarn failure are observed during tensile failure.

Tailoring Optoelectronic Properties of ZnO Nanoparticles via Incorporation of Multiwalled Carbon Nanotube Contents on of ZnO/MWCNT Nanocomposites

The present study demonstrates the tailoring of optoelectronic properties of ZnO nanoparticles (NPs) by adding multi-walled carbon nanotubes (MWCNTs) at different weight ratios. ZnO/MWCNT nanocomposites were successfully prepared using the solution blending method, and the optical spectra of all samples were determined using a UV–vis spectrometer. An increase in the optical absorption coefficient (α) and extinction coefficient (k) was observed with an increase in MWCNT content, resulting in the significant ability to attenuate incident light in ZnO/MWCNT nanocomposites compared to pure ZnO NPs. The optical band gap of pure ZnO NPs decreased from 3.26 eV to 2.58 eV in the ZnO/50 wt% MWCNT nanocomposite. The refractive index values ranged from 1.66 to 1.61 as the wavelength varied between 400 nm and 700 nm. Furthermore, the incorporation of MWCNTs in the ZnO/MWCNT nanocomposite had an impact on various dispersion parameters related to the refractive index. With increasing MWCNT content, the dielectric constant (ε 0) decreased from 2.40 to 1.96, while the mean oscillator wavelength (λ 0) increased from 157.7 nm to 164.2 nm and the oscillator strength (S0) decreased from 5.93 × 10−5 nm−2 to 3.70 × 10−6 nm−2. The localized density of state (N/m*) increased from 7.45 × 1057 to 20.8 × 1057 (m3 Kg) −1, and the long wavelength refractive index (ε ∞) rose from 3.683 to 4.745. Moreover, the plasma frequency (ω p) of the electron exhibited an increase from 2.15 × 1031 to 6.01 × 1031 Hz. These findings highlight the potential of tailoring the optoelectronic properties of ZnO NPs through the incorporation of MWCNTs, paving the way for the development of novel materials with improved optoelectronic characteristics for a wide range of applications.

Effects of Multi-Walled Carbon Nanotube Dosages and Sonication Time on Hydration Heat Evolution in Cementitious Composites.

This study aimed to investigate the heat generated during the hydration process in cementitious composites containing multi-walled carbon nanotubes (MWCNTs). The cumulative heat release and heat flow of these cementitious composites were measured over a period of 168 h using isothermal calorimetry. Three different MWCNT dosages, 0.05 wt%, 0.1 wt%, and 0.2 wt%, along with two different sonication times for the solution, which were 20 min and 60 min, were applied in the experimental program. The results reveal that the incorporation of MWCNTs and the use of a naphthalene-based superplasticizer to disperse the nanotubes generally led to a reduction in heat emission during the early stages of hydration, a lower first peak value in the initial stage of hydration, and a significant delay in the acceleration period compared with the reference sample lacking this superplasticizer. Furthermore, the results demonstrate that both the dosage of multi-walled carbon nanotubes (MWCNTs) and the sonication time have an impact on the heat emission and hydration process since the same amount of superplasticizer was applied to all pastes. An increase in the MWCNT dosage led to a decrease in the rate of hydration heat at the main peak for all pastes. Additionally, longer sonication times resulted in lower values of heat generated, reduced main peak values in the heat rate evolution, and generally extended delays in the occurrence of the main peak.

Improved electrochemical performance of multi-walled carbon nanotube reinforced gelatin biopolymer for transient energy storage applications.

Multi-walled carbon nanotube (MWCNT) incorporated biodegradable gelatin nanocomposites (Gel/MWCNT) have been prepared following a facile solution processing method. The Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electronic microscopy (FESEM), and water contact angle (WCA) measurements revealed improved structural properties and surface morphological features of the nanocomposite films due to the incorporation of MWCNT. A four-fold decrease in the DC resistivity was obtained due to the addition of MWCNTs. The specific capacitance of the nanocomposite increased from 0.12 F/g to 12.7 F/g at a current density of 0.3 μA/cm2 due to the incorporation of 0.05 wt.% MWCNT. EIS analysis and the corresponding Nyquist plots demonstrated the contributions of the different electrical components responsible for the improved electrochemical performance were evaluated using an equivalent AC circuit. The incorporation of MWCNTs was found to reduce the charge-transfer resistance from 127 Ω to 75 Ω and increase the double-layer capacitance from 4 nF to 9 nF. The Gel/MWCNT nanocomposite demonstrated improved cyclic stability with a retention of 95% of the initial capacitance even after 5000 charging/discharging cycles. The biodegradability test showed that the nanocomposite degraded completely after 30 hours of immersion in water. This fully biocompatible nature of the nanocomposites with high specific capacitance and low charge transfer resistance may offer a promising route to fabricate a nature-friendly electrode material for energy storage applications.

Effect of incorporation of multi-walled carbon nanotubes on the CO2/CH4 separation performance of sulfonated poly (ether ether ketone) / polyetherimide composite membranes using design of experiments and molecular dynamics simulation methods

Blend membranes were prepared based on sulfonated poly (ether ether ketone) (SPEEK) and poly (etherimide) (PEI) using different amounts of multi-wall carbon nanotubes (MWCNTs) (up to 2 wt%). PEEK has been sulfonated directly to reach 70 % degree of sulfonation. The manufactured membranes were examined by X-ray diffraction (XRD), scanning field emission electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FTIR). The effect of the composition of SPEEK / PEI on membrane selectivity was investigated under different feed pressures (2 to 8 bar) and temperatures (25 to 55 °C). The values of selectivity and gas permeability were varied between the value of the individual polymers, fluctuating systematically with SPEEK / PEI content variation in the blends. TGA and tensile tests result obtained for prepared membranes shown that the hybrid membrane had good thermal and mechanical properties. The addition of MWCNTs to the blend led to simultaneously improve the selectivity and permeability of the pair gases of CO2 and CH4. The permeability of CO2, as well as CH4/CO2 selectivity for the membrane with the same weight of SPEEK and PEI, and 1 wt% of MWCNTs (coded SP55M1) experienced an increase of about 22 % compared with the neat membrane. Molecular dynamics simulations (MDS) were performed by employing the COMPASS force field to estimate the diffusivity of CH4 and CO2 gases through selected membranes. At last, with compared to the obtained experimetal data, the optimized nanocomposite membrane, integrated with MWCNTs was efficient, which makes it promising platform to separate mixed gase flows of CO2 and CH4 and other related environmental processes.

NiS2 @MWCNTs as a promising anode material for lithium and sodium-ion batteries with superior cycling stability

The NiS2 @MWCNTs materials were synthesized using a straightforward hydrothermal one-step process, forming a 3D conductive network structure with stable and uniformly distributed nanosphere morphology. Electrochemical tests yielded a sodium storage capacity of 463.99 mAh g−1 after 400 cycles with 0.2 A g−1, and a coulomb efficiency of 83.3% at the first cycle, followed by excellent long-cycle stability with a capacity retention rate of 96.7% after 600 cycles at a high current of 1 A g−1. It's interesting to note that Na+ storage mechanism is provided by a pseudocapacitor. The 3D conductive network was credited with enhanced electrochemical performance and structural stability. The incorporation of multi-walled carbon nanotubes (MWCNTs) also improves the material conductivity and accelerated the ion transport efficiency, while modulation of the nano microsphere structure increases the reactive active sites and reduce the capacity loss. These findings highlight the great potential NiS2 @MWCNTs composites as a perfect anode material for sodium-ion batteries (SIBs), opening up new possibilities for sustainable energy storage solutions.

Thermo-mechanical characterization of electrospun polyurethane/carbon-nanotubes nanofibers: a comparative study

Creating ultrathin, mountable fibers from a wide range of polymeric functional materials has made electrospinning an adequate approach to producing highly flexible and elastic materials. In this paper, electrospinning was utilized to produce thermoplastic polyurethane (TPU) nanofibrous membranes for the purpose of studying their thermal and mechanical properties. Towards a study of the effects of fiber orientation and multi-walled carbon nanotubes (MWCNTs) as a filler on both mechanical and thermal characteristics of electrospun TPU mats, an experimental comparison was held between unidirectional and randomly aligned TPU and TPU/MWCNTs nanofibrous structures. The incorporation of MWCNTs into randomly oriented TPU nanofibers resulted in a significant increase in Young's modulus (E), from 3.9 to 7.5 MPa. On the other hand, for unidirectionally spun fibers, Young's modulus increased from 17.1 to 18.4 MPa upon the addition of MWCNTs. However, dynamic mechanical analysis revealed a different behavior. The randomly oriented specimens exhibited a storage modulus with a significant increase from 180 to 614 MPa for TPU and TPU/MWCNTs mats, respectively, and a slight increase from 119 to 143 MPa for unidirectional TPU and TPU/MWCNTs mats, respectively. Meanwhile, the loss modulus increased with the addition of MWCNTs from 15.7 to 58.9 MPa and from 6.4 to 12 MPa for the random and aligned fibers, respectively. The glass transition values for all the mats fell in the temperature range of – 60 to − 20 °C. The thermal degradation of the membranes was not significantly affected by the addition of MWCNTs, indicating that the mixing of the two constituents did not change the TPU’s polymer structure and that the TPU/MWCNTs nanocomposite exhibited stable thermal degradation properties.

Redox additives dependent supercapacitor performances of ZnO/SnO2@MWCNT nanocomposites

The poor cyclic stability arose from the low conductivity and strong electrostatic interaction between the ions remain the formidable challenge on the development of ZnO/SnO2 based electrodes for high-performance supercapacitor devices. Herein, an effective strategy was developed to achieve the higher conductivity by the growth of ZnO/SnO2 nanocomposites (NCs) on multiwalled carbon nanotube (MWCNT) through hydrothermal approach. Physiochemical characteristics of the synthesized ZnO/SnO2@MWCNT (ZSM) NCs were investigated by the XRD, FT-IR, SEM, HR-TEM, and XPS analyses. The fabricated working electrodes performances were examined for supercapacitor devices under pure 1 M Na2SO4 (NSE) and 0.1 M K4[Fe(CN)6] added redox additive electrolytes (RAE). The fabricated working electrode showed 297 Fg−1 specific capacitance in NSE and it was increased to 3885 Fg−1 under RAE. The fabricated working electrode possessed the cyclic retention of 81.15 % even after consecutive 5000 GCD cycles and it was enhanced up to 84.42 % in RAE. Also, incorporation of redox additives, greatly enhanced the energy and power densities of the fabricated device and they were found to be 22.50 Whkg−1 and 3200 Wkg−1, respectively in RAE. It confirmed that the incorporation of MWCNT in electrode material and RAE, greatly improved the overall efficiency of the ZnO/SnO2 based supercapacitors.

The effect of cross-linking system and reinforcement on the cross-linking reaction of peroxide vulcanized ethylene-propylene-diene terpolymer (EPDM) matrix

In this work, the effect of using of dicumyl-peroxide (DCP) (2, 5 & 8 phr) and co-agent triallyl-cyanurate (TAC) (2, 4 & 6 phr) as cross-linking system as well as multi-walled carbon nanotubes (MWCNTs) (5, 8 και 10 phr) as a filler, for ethylene-propylene-diene terpolymer (EPDM) was investigated. Differential scanning calorimetry (DSC) was employed in order to study the progress of the cross-linking reaction, based on the exothermic vulcanization peaks of isothermal (at 160, 170, 180, 190 °C) and non-isothermal experiments (with heating rates 5, 10, 25, 50 °C min−1). The autocatalytic model was successfully applied to the results of isothermal experiments and the activation energy (Ea) of the reaction was calculated, based on the Arrhenius equation. The Ozawa-Kissinger equations were also applied to the data obtained from the non-isothermal study. From the results obtained from isothermal DSC experiments, an increase was observed in the reaction rates accompanied with a decrease in Ea with the increase of DCP content, whereas a proportional relationship between TAC content and the enthalpy and Ea of the reaction was recorded. The incorporation of MWCNT’s in EPDM increased its Ea. From the non-isothermal DSC experiments, a significant increase in the enthalpy and Ea of the cross-linking reaction was observed at higher DCP content, whereas TAC content did not show any notable effect on the reaction. Based on the results of this research, it is concluded that the increase of peroxide content facilitates the vulcanization of EPDM, whereas inhibition was observed by the incorporation of MWCNT’s.

Accelerating Thermal Transfer in Perovskite Films for High‐Efficiency and Stable Photovoltaics

AbstractHeat accumulation within in‐service perovskite solar cells (PSCs) under light irradiation is one imminent threat in deteriorating the persistent power output and long‐term durability. Herein, a novel strategy is reported to remove dissipated heat by improving the thermal conductivity and thermal diffusivity of perovskite film with multi‐walled carbon nanotubes (MWCNTs) as additives. Benefiting from the interaction between perovskite and MWCNTs as well as the accelerated heat transfer kinetics mediated by MWCNTs, this method produces a high‐quality perovskite film with high crystallinity and reduced defects. Meanwhile, the incorporation of MWCNTs self‐cools the operational temperature of final PSC from 42.5 to 38.5 °C to compensate the high temperature‐induced performance reduction. Consequently, a significantly improved efficiency of 11.78% for carbon‐based CsPbIBr2 cell, 15.14% for carbon‐based CsPbI2Br cell, 22.13% and 23.05% for regular and inverted (FA0.83MA0.17)0.95Cs0.05Pb(I0.9Br0.1)3 cells, respectively, is achieved. Apart from the larger power conversion efficiency conservation rate > 94% over 2800 h in air without encapsulation, the optimal device demonstrates significant stability improvement by nearly 1.5‐times after thermal aging at 85 °C for 1300 h and 40‐fold after persistent operation for 350 h, providing a new path for high‐efficiency and stable perovskite platforms.