Combination Of Carbon Nanotubes Research Articles

Synergistic carbon nanotube ＋ carbon-coated iron nanoparticle polymer composites: Electrical, magnetic, and mechanical properties

Composite multifunctionality enabled by nanofiller modification has been widely explored in diverse applications. To date, work in this area has focused overwhelmingly on polymers modified with only a single type of nanofiller. Even studies that use more than one type of filler generally do so in order to achieve just a single type of multifunctionality—for example, modification with a combination of carbon nanotubes (CNTs) and graphene for higher electrical conductivity. Much less work has been done in the area of modifying polymers with multiple nanofiller types having dissimilar properties. To that end, we modify a representative polymer (epoxy) with a combination of multi-walled (MW)CNTs and carbon-coated iron nanoparticles (CCFeNPs). These phases give rise to combined electrical and magnetic properties in the MWCNT ＋ CCFeNP composite. DC and AC conductivity, permittivity, permeability, elastic modulus, and piezoresistive gauge factor were measured for varying relative concentrations of MWCNTs and CCFeNPs. Synergistic effects were observed, such as higher electrical conductivity and magnetic permeability in MWCNT ＋ CCFeNP composites. More specifically, composites containing 0.4 wt% MWCNT ＋ 0.1 wt% CCFeNP increased in DC conductivity by 0.5-0.6 S/m compared to 0.5 wt% MWCNT-only specimens. Furthermore, 0.1 wt% MWCNT ＋ 0.4 wt% CCFeNP composites showed a magnetic saturation increase of 1.66 × 10−4 emu/cm3 over 0.5 wt% CCFeNP-only composites.

Bi2Te3/Carbon Nanotube Hybrid Nanomaterials as Catalysts for Thermoelectric Hydrogen Peroxide Generation

Harnessing waste heat from environmental or industrial sources presents a promising approach to eco-friendly and sustainable chemical synthesis. In this study, we introduce a thermoelectrocatalytic (TECatal) system capable of utilizing even small amounts of heat for hydrogen peroxide (H2O2) production. We developed a nanohybrid structure, combining carbon nanotubes (CNTs) and Bi2Te3 nanoflakes (Bi2Te3/CNTs), through a one-pot synthesis method. Bi2Te3, as a thermoelectric (TE) material, generates charge carriers under a temperature gradient via the Seebeck effect, enabling them to participate in surface redox reactions. However, the rapid recombination of these charge carriers greatly limits the TECatal activity. In the Bi2Te3/CNTs nanohybrid system, the introduction of CNTs substantially enhances the efficiency of H2O2 production, as the strong bonding between CNTs and Bi2Te3, along with the excellent conductivity of CNTs, facilitates charge carrier separation and transport, as confirmed by TE electrochemical tests. This study underscores the significant potential of thermoelectric nanomaterials for converting waste heat into green chemical synthesis.

A Breathable and Strain‐Insensitive Multi‐Layered E‐Skin Patch for Digital Healthcare Wearables

AbstractIn this study, a breathable and strain‐insensitive multi‐layered electronic skin (e‐skin) capable of real‐time detection and distinction of electrocardiogram (ECG) signals, temperature, and skin hydration is developed. Leveraging a scalable benchtop method, sensing elements are transferred onto porous and hydrophobic substrates, followed by multi‐layer stacking to enable multimodal sensing. The sensing elements, a combination of carbon nanotube and nanoporous carbon (CNT@NPC) ink, are applied using strain‐insensitive patterned masks, then spray‐coated with styrene–ethylene–butylene–styrene (SEBS) to create a hierarchical porous network through phase separation. The CNT@NPC networks exhibit an improvement in strain insensitivity with active sensing capabilities due to their adaptable molecular tuning capacity and exceptional electrical conductivity. The porous SEBS substrate offers strong bonding with CNT@NPC attributed to the π–π interactions and high kinetic energy dispersion from spray coating allowing effective transfer. This unique design facilitates breathability, and miniaturization that minimizes the interference between different sensing modalities, ensuring accurate and reliable data acquisition. The breathability (3.49 mg cm−2 h−1) and the non‐smearing nature of the multi‐layered e‐skin enables simultaneous monitoring of temperature (0.198% °C−1), skin hydration (relative humidity = 0.77% %−1), and ECG (26 ± 1 dB) with continuous data transmission to a remote smartphone interface.

Potassium Ion-Assisted Self-Assembled MXene-K-CNT Composite as High-Quality Sulfur-Loaded Hosts for Lithium-Sulfur Batteries.

We successfully synthesized hybrid MXene-K-CNT composites composed of alkalized two-dimensional (2D) metal carbide and carbon nanotubes (CNTs), which were employed as host materials for lithium-sulfur (Li-S) battery cathodes. The unique three-dimensional (3D) intercalated structure through electrostatic interactions by K+ ions in conjunction with the scaffolding effect provided by CNTs effectively inhibited the self-stacking of MXene nanosheets, resulting in an enhanced specific surface area (SSA) and ion transport capability. Moreover, the addition of CNTs and in situ-grown TiO2 considerably improved the conductivity of the cathode material. K+ ion etching created a more hierarchical porous structure in MXene, which further enhanced the SSA. The 3D framework effectively confined S embedded between nanosheet layers and suppressed volume changes of the cathode composite during charging/discharging processes. This combination of CNTs and alkalized nanosheets functioned as a physical and chemical dual adsorption system for lithium polysulfides (LiPSs). When subjected to a high current at 1.0C, S@MXene-K-0.5CNT with S-loaded of 1.2 mg cm-2 had an initial capacity of 919.6 mAh g-1 and capacity decay rate of merely 0.052% per cycle after 1000 cycles. Moreover, S@MXene-K-0.5CNT maintained good cycling stability even at a high current of up to 5.0C. These impressive results highlight the potential of alkalized 2D MXene nanosheets intercalated with CNTs as highly promising cathode materials for Li-S batteries. The study findings also have prospects for the development of next-generation Li-S batteries with high energy density and prolonged lifespans.

High‐performance resistive/capacitive pressure sensor applied on smart insoles detecting abnormal activity

AbstractThis paper presents an approach to pressure sensors with dual‐function resistors and capacitors implemented with interdigitated capacitors fabricated on a flexible substrate for detecting abnormal actions during walking. In this study, we proposed a highly sensitive, broad‐range pressure sensor achieved through a combination of porous Ecoflex, carbon nanotubes (CNTs), coating single‐wall carbon nanotubes (SWCNTs), and interdigitated electrodes. First, characterizations of the capacitor and resistor sensor applied onto cotton fabric are completed by precision LCR meter across the frequency at 50 kHz. Subsequently, the presence of volume fraction CNTs enhances the bond strength of composites, and coating SWCNT improves sensor sensitivity. The robustness of our presented sensor is validated through testing under high pressure (50 kPa) for more than 1000 cycles. Furthermore, the combination of CNTs and porous dielectric, along with SWCNT coating, achieves a broad detection range (500 kPa) with a sensitivity range from 0.018 (at 500 kPa) to 0.15 (at 5 kPa). Finally, our high‐performance resistive/capacitive pressure sensor applied on smart insoles represents a significant advancement in wearable technology for health monitoring and safety applications. Leveraging an advanced autoencoder, our proposed sensor accurately detects abnormal activity patterns, such as sudden stops or irregular gait, thereby alerting users to potential safety concerns. Its ability to detect abnormal activity patterns enhances user safety and well‐being, making it a tool for various healthcare and fitness applications.

Developing a piezoresistive sensor based bionic neurological intraoperative monitoring system for spine surgery skill training.

This research aims to tackle the limitations faced in surgical education nowadays, particularly in the complex field of spinal cord tumor removal surgery. An innovative flexible piezoresistive sensor designed to mimic a motor nerve was developed and integrated into a bionic spine surgery simulation system, allowing for the intraoperative nerve monitoring possible during simulated tumor removal surgeries. The motor nerve, fabricated using a combination of carbon nanotubes and silicone rubber, exhibited a strong correlation between applied force and resultant changes in resistance, as confirmed by experimental results. This creative system can play an important role in providing valuable feedback for training doctors, facilitating the assessment of surgical precision and success, and enabling doctors to take necessary precautions to minimize the risk of nerve damage in real surgical scenarios. Ultimately, this proposed system has the potential to elevate the standard of surgical education, foster skill development among doctors, and significantly contribute to enhanced patient care and recovery.

Multi-walled carbon nanotubes with embedded nickel sulphide as an effective electrocatalyst for Bi-functional water splitting

Water-splitting presents a viable solution to expanding energy needs. To maximise water-splitting performance, transition metal sulphides, a very efficient electrocatalyst, have been extensively researched. It is unable to generate hydrogen (H2) and oxygen (O2) because to active sites and weak electrical conductivity. Some carbon-based materials offer superior dispersion capacities and bigger active sites for charge transfer to circumvent these restrictions. This work presents an efficient electrocatalyst combining carbon nanotubes (CNTs) and electrochemically active Nickel sulphides, Ni17S18 (NiS), synthesized by using a wet-chemical approach. The improved electrocatalytic performance of NiS@CNTs can be attributed to higher surface area and higher electrical conductivity of CNTs. Furthermore, linear-sweep voltammetry (LSV) and electrochemical impedance analysis (EIS) were also utilized for the electrochemical investigations. The addition of CNTs to NiS showed a over-potential of 330 mV at 40 mA cm−2, with a Tafel slope of 47 mV dec−1 for OER. Similarly, we have also investigated the HER activity of the as-prepared electrocatalysts at the same current density, having a over-potential of 280 mV with a Tafel slope of 102 mV dec−1.

Electrochemical performance of SnS-SnS2@CNTs composites as anode materials for Sodium ion batteries

Tin sulfide based materials are attracting attention because of excellent performance as SIBs anode. However, SnS and SnS2 suffer from severe capacity degradation during the charge/discharge process, as well as high volume expansion, which prevents superior cycling stability of SIBs. In this work, carbon nanotubes (CNTs) modified SnS-SnS2 materials were prepared by a facile one-step solvothermal approach. The constructed SnS-SnS2 heterostructures have a special internal electric field that promotes charge transfer. The combination of CNTs also prevents agglomeration of active particles and improves the capacity and cycling durability of SIBs (413 mAh·g−1 after 50 cycles).

Experimental Investigation on the Grouting Performance of Foam-CNT Composite Grouts in Vertical Inclined Fractures Under Flowing Condition

Abstract Grouting is an effective method to solve the problem of water inrush in tunnel and underground engineering. However, rock fractures are often simplified as horizontal and smooth fractures in most grouting studies, while studies on vertical inclined fractures are still rare. To investigate the diffusion law in vertical inclined fractures, a vertical inclined fracture grouting simulation device was developed. A new type of cement slurry with low weight and high flowing water resistance was developed by combining carbon nanotube (CNT) slurry with foamed cement. Physical simulation experiments were conducted to investigate various factors (initial flowing water, inclination angle, sand content, and grouting rate) on the sealing efficiency of grouting. Results show that the high foam content has a negative effect on the compressive strength of the slurry, and has a positive effect on the fluidity and water resistance. The optimum ratio of slurry is 30% foam content, 1.0% CNT content, 1.3 water/cement ratio, and 3% additive content. The inclination angle and inclination direction of the fracture have a great influence on the sealing efficiency of grouting. Foam-CNT composite grouts can meet the requirement of flowing water grouting in vertical inclined fractures.

Ultralight anisotropic Ti3C2Tx MXene/Carbon nanotube hybrid aerogel for highly efficient solar steam generation

Solar steam generation (SSG) has been considered as a promising method to produce fresh water from seawater. Due to high light absorption and excellent chemical stability, carbon nanotube (CNT) has been widely used for SSG. However, it is still challenge to simultaneously realize high water evaporation rate and energy efficiency for CNT based solar steam generator. Herein, ultralight anisotropic Ti3C2Tx MXene/carbon nanotube (A-Ti3C2Tx/CNT) aerogels are designed and fabricated for highly efficient SSG. The combination of CNT and Ti3C2Tx MXene endows the hybrid aerogel with high light absorption and effective localized surface plasmon resonance (LSPR), resuting in enhanced light-to-heat conversion efficiency. The porous structure of aerogel leads to multiple scattering and absorption, further contributing to the photothermal conversion process. Moreover, the low thermal conductivity of aerogel structure effectively reduces the heat loss to environment. Through tailoring the anisotropic channel, the A-Ti3C2Tx/CNT hybrid aerogel with average channel size of 80 μm possesses most efficient water transport due to the capillary effect and formation of intermediate water. Therefore, the A-Ti3C2Tx/CNT hybrid aerogel exhibits high average light absorption of 95.68% in the wavelength range of 200–2500 nm, excellent water evaporation rate of 2.10 kg m−2 h−1 under 1 sun irradiation (1 kW m−2) with a high energy efficiency of 93.4%, and remarkable durability with 7 days continuous water evaporation. The A-Ti3C2Tx/CNT hybrid aerogel also shows high resistance to salt crystallization due to its high salt transport flux of 1.90 kg m−2 h−1. This work offers a prospective strategy for constructing highly efficient solar steam generator with stable performance for practical application in seawater desalination.

Enhanced electrochemical performances of SrMoO4/MWCNT-PVP nanocomposites as electrocatalyst for hydrogen evolution reaction

In this work, we have successfully synthesized the cost-effective, abundant in nature and environmentally friendly SrMoO4/MWCNT-PVP by using the co-precipitation technique for hydrogen evolution reaction (HER). Prepared nanocomposites were characterized by XRD, which confirms the formation of tetragonal structure of SrMoO4 and indexed with JCPDS (01-074-3912). Raman spectra confirm the combination of SrMoO4 with carbon composite (verified by D and G band 1.02 ID/IG ratio) and its functional group was further analyzed with the help of FTIR spectra. Synthesized product morphology was characterized by using SEM and TEM images, which confirms formation of well-defined dumb-bell shaped nanostructures with the combination of carbon nanotube and also it further confirms the formation of polycrystalline nature of the material. The elemental composition was analyzed by EDS images, which confirms the occurrence of Sr, Mo, O, and C in an appropriate form with a uniform distribution, respectively. MWCNT in SrMoO4 incorporation led to decrease overpotential of 204 mV and 110 mV/dec Tafel slope of the material, which was examined by the LSV curves and Tafel plot analysis. Electrochemical impedance spectroscopy was also investigated, and it delivered the small charge-transfer resistance of 248 Ω, which further supporting the HER analysis and denoting the promising HER kinetics. Therefore, our work unlocks a new path for the properly tuned nanostructured morphology of metal oxide with carbon composite for electrochemical hydrogen evolution reaction application.

Universal carbon nanotubes-polybenzimidazole SPME coating and its application for both gas and liquid chromatography

In this study, we present a novel combination of carbon nanotubes (CNT), widely used as a sorbent material in solid-phase extraction-based methodologies, with Polybenzimidazole (PBI), recently introduced as a universal...

Synergistic VSV Virotherapy and Carbon Nanotube Photothermal Therapy for Osteosarcoma in Murine Models.

Wide resection is usually performed for malignant bone and soft tissue tumors, but there is often functional impairment of the affected limb. In this study, we performed virotherapy with the vesicular stomatitis virus (VSV) and photothermal therapy using carbon nanotubes (CNTs) in combination for osteosarcoma, followed by marginal excision. The possibility of local treatment of the primary tumor was then assessed. LM-8 cells (1×107) were subcutaneously implanted into 5-week-old mice to generate an in vivo osteosarcoma mouse model. Marginectomy was performed. Four groups with six mice each were created: VSV+SWCNTs group, VSV group, SWCNTs group, and an untreated group. Tumor margin resection was performed 2 weeks after tumor cell transplantation. The primary tumor volume, local recurrence, distant metastasis, and survival rate were evaluated. The combination of VSV virotherapy and CNTs photothermal therapy resulted in shrinkage of the primary tumor and reduced local recurrence after marginectomy. There was no significant difference in distant metastasis or survival rate for all groups. Combining virotherapy with VSV and CNTs photothermal therapy is useful for local treatment of osteosarcoma in murine models, possibly allowing for smaller tumor resection margins.

Nanocomposites of Ni-Co-Mn MOFs and PANI functionalized CNTs-GNPs with excellent electrochemical performance for energy storage applications

Supercapacitors, pivotal for eco-friendly energy solutions, demand efficient Ni-Co-Mn MOF-based electrodes. These electrodes, combining carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), and polyaniline (PANI), were created through a facile ultrasonication-assisted solvothermal method, fostering their utility in energy storage systems. Scanning electron microscopy (SEM) reveals a distinctive flower-like morphology that facilitates faradic reactions. X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy confirm composition and functional group analysis. Comparative studies demonstrate the superiority of the Ni-Co-Mn/PCG (PANI-CNT-GNP) nanocomposite in charge storage over pristine Ni-Co-Mn MOF. Notably, the Ni-Co-Mn/PCG-40 nanocomposite, with 40 mg of PCGs, exhibited outstanding electrochemical performance, boasting the highest specific capacity (1238C/g @ 2 Ag), minimal internal reversibility, and excellent stability. This enhanced performance is attributed to efficient interconnected pathways and the uniform flower-like structure that aids in both electron and ion transportation. The asymmetric supercapacitor assembled from Ni-Co-Mn/PCG-40 showcased exceptional metrics: 380C/g @ 0.7 Ag specific capacity, a maximum energy density of 90 Wh/kg, a maximum power density of 17,000 W/kg, and 100 % stability over 5000 cycles. This research suggests a promising, cost-effective, and environmentally friendly supercapacitor solution for energy storage applications, addressing both pollution mitigation and energy crisis concerns.

In-situ synthesis of conductive Fe-MOFs on the carbon nanotubes/carbon cloth as high-performance catalyst for alkaline oxygen evolution

In the electrolysis of water, the efficiency is heavily constrained by the slow kinetic process of the oxygen evolution reaction (OER) at the anode. Herein, by a simple hydrothermal method for the in-situ growth of Fe3(HHTP)2 on the open three-dimensional nanostructured substrate, Co-anchored carbon nanotubes/carbon cloth (Co/CNT/CC), Fe3(HHTP)2@Co/CNT/CC was prepared and acted as an OER electrocatalyst. The combination of carbon nanotubes (CNTs) and carbon cloth not only enhanced the substrate conductivity, but also facilitated the uniform loading of Fe3(HHTP)2. The in-situ growth, on the other hand, allowed the Fe3(HHTP)2 to connect with the conductive substrate tightly, thus enhancing the stability of the interfacial contact, improving the electron transfer efficiency and providing enough catalytically active sites. In addition, the construction of self-supported electrodes could effectively avoid the use of binders and improve the stability of the composites during electrolysis. The Fe3(HHTP)2@Co/CNT/CC displayed excellent properties in alkaline electrolytes as an efficient OER catalyst, achieving a current density of 50 mA cm−2 at an overpotential of only 1.60 V and perfect stability in long-term tests. Herein, the present work provides a rational tactics for developing self-supporting electrodes with plentiful active sites and high stability to enhance the electrochemical efficiency of water splitting.

Preparation of washable and salt-resistant composites for continues solar-driven evaporation and seawater desalination based on ES nonwovens

Solar-powered interfacial evaporation is a novel and eco-friendly technology for producing fresh water from seawater. However, current interfacial evaporators are expensive to manufacture, have poor tolerance for environmental conditions, and struggle to achieve stable evaporation in highly saline solutions while also preventing salt accumulation. Therefore, the fabrication of user-friendly, long-lasting, and salt-resistant interfacial evaporators remains a significant challenge. In this study, an efficient and durable interfacial evaporator was fabricated by embedding hydroxyl dobby carbon nanotubes (CNTs) and polydopamine (PDA) onto ES nonwoven fabrics. The prepared PDA-CNT-ES (PCES) composite-evaporator exhibited excellent light absorption and hydrophilic properties, which can be attributed to the light absorption capabilities of carbon nanotubes and the hydrophilicity of PDA. The combination of CNTs and PDA coatings produced a synergistic effect, leading to an efficient photothermal performance of the evaporator surface, which resulted in a significant evaporation rate of 1.29 kg⋅m−2⋅h−1 and a solar thermal efficiency of 90.77% under 1.0 solar irradiation (1 kW⋅m−2). The PCES composites, in particular, demonstrated effective purification under various simulated seawater conditions, and the desalinated water produced met the standards for potable water. The composites exhibited remarkable durability and stability over 10 desalination cycles. These results provide new insights for applying these findings in seawater desalination and wastewater treatment.

Carbon Nanotube Network Topology-Enhanced Iontronic Capacitive Pressure Sensor with High Linearity and Ultrahigh Sensitivity.

Flexible capacitive pressure sensors with high sensitivity over a wide pressure range are highly anticipated in the fields of tactile perception and physiological signal monitoring. However, despite the introduction of microstructures on the electrolyte layer, the deformability is still limited due to the size limitation of the microstructures, making it difficult to significantly improve the sensitivity of iontronic capacitive pressure sensors (ICPSs). Here, we propose an innovative strategy of combining carbon nanotubes (CNTs) topological networks and ionic hydrogel micropyramid array microstructures that can significantly enhance the sensitivity of flexible ICPSs for ultrasensitive pressure detection. Compared with other previously reported ICPSs, the sensor developed in this work exhibits an unprecedented sensitivity (Smin > 1050 kPa-1) and a high linear response (R2 > 0.99) in a wide pressure range (0.03-28 kPa) enabled by CNT percolation networks inside the microstructred electrolyte layer. This ultrasensitive and flexible ICPS also can effectively detect pressure from a variety of sources, including sound waves, lightweight objects, and tiny physiological signals, such as pulse rate and heartbeat. This work provides a general strategy to achieve an ICPS with both broader pressure-response range and higher sensitivity, which provides a stable and efficient way for a low-cost, scalable sensor for sensitive tactile sensing in human-computer interaction applications.

Energy storage investigation of solar pond integrated with PCM and nanoparticles during winter season in Chennai

Solar energy is a highly regarded renewable energy sources that are attracting substantial attention owing to its potential to alleviate climate change and provide sustainable energy. Solar ponds are one approach to collect solar energy by capturing and storing thermal energy inside a pond. However, the effectiveness of solar ponds has been hampered by reasons such as heat loss, evaporation, and inadequate heat transmission. Researchers have investigated the use of phase change materials (PCMs) and nano-additives to improve the performance of solar ponds in order to overcome these issues.Large amounts of heat can be stored and released by substances known as phase change materials as they transition between two states. By adding PCMs into solar ponds, heat may be retained throughout the day and released at night when the sun is not shining. Alternatively, nano-additives have the potential to enhance the efficiency of a solar pond by improving the heat transfer properties of the fluid present in it.To measure the thermal efficiency of the solar pond, multiple phases of an experiment have been undertaken to establish the degree of thermal efficiency. During the experiment, various parameters were employed to measure and track the temperature variations in the lower convective zone (LCZ) of the solar pond. These measurements were recorded on a daily, weekly, and hourly basis, taking into account the depth of the solar pond as a determining factor. There was also an experiment carried out using micro PCMs and paraffin waxes (PCMs) that were combined into the matrix. In this study, nanoparticles with high thermal conductivity, such as carbon nanotubes (CNTs), and hybrid nanoparticles, such as AgTiO2, were utilized.The solar pond without phase change material (PCM) had an average temperature of 45 °C in the lower convective zone (LCZ). When PCM was added to the solar pond, the maximum temperature in the LCZ increased by 2 °C compared to the previous 24 h. Furthermore, when carbon nanotube (CNT) nanoparticles were incorporated into the solar pond with PCM at the base, the temperature was observed to be 1.3 °C higher compared to a typical solar pond that only used PCM for heat storage. In another scenario, the solar pond with PCM and a combination of CNT and AgTiO2 nanoparticles had an average temperature of 52.5 °C in the LCZ during the first week of observation.

Development of nanomodified eco-friendly thermal energy storing cementitious composite using PCM microencapsulated in biosourced encapsulation shell

This study presents the development of a thermal energy storing cementitious composite that incorporates phase change material (PCM) microencapsulated in biosourced polymer shell (m-PCM). The biodegradability of the encapsulated PCM was assessed using Nuclear Magnetic Resonance (NMR), which confirmed the high biodegradability of the m-PCM shell under specific environmental conditions. To examine the thermophysical properties of the m-PCM, Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) were performed. The DSC results revealed exothermic enthalpies of 84.7 J/g and 140.2 J/g, with associated peak temperatures of − 3.2 °C and − 22.9 °C, respectively. Subsequently, the m-PCM was incorporated into cement-based mortar at proportions of 5%, 10%, and 15% by weight of binder. Uniaxial compression tests were conducted to evaluate the effect of the m-PCM on the mechanical properties of the mortar. The results indicated a significant decrease in mechanical strength upon incorporating the m-PCM. However, this reduction in strength was mitigated by the addition of silica fume (SF) and multiwalled carbon nanotubes (MWCNTs) in combination. Furthermore, a thermal cycling test was performed to examine the behavior of the nanomodified m-PCM incorporated mortar under varying ambient conditions. The results showed that the addition of MWCNTs improved both the mechanical performance and thermal performance of the composite.

Thermal energy compensation strategy to achieve rambutan-like CoFe@C-CNTs composites with controllable cross-linked networks for broadband microwave absorption

Combining carbon nanotubes (CNTs) with dielectric/magnetic materials is an attractive strategy to obtain high-performance microwave absorbing materials. However, it remains great challenges to overcome the agglomeration of CNTs and balance magnetic components to achieve impedance matching and broadband absorption. Herein, a thermal energy compensation strategy is designed to construct rambutan-like CoFe@C-CNTs composites with excellent microwave absorption performances via a catalyst chemical vapor deposition method and the subsequent reduction process. This strategy fully utilizes the thermal energy released during the C2H2 carbonization process, allowing the cracking of C2H2 and the growth of CNTs to continue at a temperature of lower than 430 °C. By adjusting the C2H2 introduction time in the cooling process of preheated cobalt iron oxide (CoFeO) nanoparticles, the number and length of CNTs on the carbon shells covering the surface of CoFeO cores can be controlled without forming metal carbides. The abundant interfaces, defects and grain boundaries in CoFe@C-CNTs composites contribute to enhancing the polarization loss via various polarizations and relaxations. Meanwhile, the appropriate 3D conductive network constructed by properly controlled CNTs provides remarkable additional conductivity loss. Furthermore, the effective retention of magnetic components greatly improves the impedance matching of the composites and offers considerable magnetic loss. Therefore, the optimized CoFe@C-CNTs-3 composite shows an effective absorption bandwidth of 9.00 GHz with a thickness of 2.1 mm. The proposed thermal energy compensation strategy provides a novel insight into developing magnetic metal-CNTs composites with potential practical applications.