Search Results (104)

The primary objective of this work is to provide new solutions to increase impact protection, using a three-dimensional textile imbibed with a shear-thinning fluid. An extensive analysis showed a scarcity of research papers related to the damping capacity of deformable porous materials imbibed with non-Newtonian fluid. No studies were found for shear-thinning fluid flow inside highly compressible foams or other soft, porous materials. The damping capacity of the imbibed material was evaluated using impact with a dropping weight. Polyvinyl alcohol solution mixed with water was used for imbibition of a three-dimensional textile. Hydrophilized carbon nanofibers were also added to the solution to augment the shear-thinning behavior. The measured impact force for imbibed samples showed an important reduction compared to the impact force for the dry material. This research does not focus on flow phenomena at the microstructural level but instead aims to highlight the macroscopic attenuation effect that occurs during the compression of the imbibed material. Full article

Chitin-derived biomass carbon materials are promising supercapacitor electrode materials due to their wide availability, low cost, high specific surface area, and nitrogen doping capability. However, their practical application is limited by insufficient conductivity and cyclic stability, often requiring functional modification or integration with complementary materials. In this study, we present a novel strategy by incorporating copper sulfide (Cu₂S) into a chitin-based carbon matrix. Cu₂S, known for its high intrinsic conductivity, excellent electroactivity, and theoretical specific capacity (~335 mAh·g⁻¹), was uniformly doped into the three-dimensional carbon aerogel framework derived from chitin nanofibers (ChNF) through sol–gel, freeze-drying, and high-temperature carbonization processes. The resulting chitin-based carbon/Cu₂S composite aerogel (CChNF/Cu₂S) exhibited a hierarchical porous structure with Cu₂S nanoparticles (20–30 nm) uniformly distributed on the carbon fiber surface. Electrochemical tests demonstrated its excellent performance, achieving a specific capacitance of 852 F·g⁻¹ at 1 A·g⁻¹, highlighting the synergistic effects of the conductive Cu₂S and nitrogen-doped carbon framework for high-performance supercapacitor applications. Full article

This study is devoted to the determination of the role of aerosol spraying in the formation of NO₂ sensor properties of carbon nanofiber (CNF)-based films. This is the first paper to systematically apply the aerosol spraying technique to CNF-based films and link the spraying parameters directly to sensor performance metrics (response, signal-to-noise ratio, response times, etc.). Chemiresistive gas sensors were created based on CNFs and tested at room temperature (25 ± 1 °C). It has been shown that the increase in the concentration of the CNF/ethanol mixture used for spraying from 3 to 30 mg/mL led to a growth in sensor response from 1.2% to 12.0% at 2 ppm NO₂. The increase in the thickness of the CNF film of the sensor induced a growth in ΔR/R₀ to NO₂ that is attributed to the formation of a porous film. With increased film thickness, the response improves (from 7.0% to 10.6% at 2 ppm NO₂) as does the signal-to-noise ratio (from 735:1 to 1892:1). The creation of hybrid all-carbon composites based on CNFs and multi-walled carbon nanotubes (MWCNTs) resulted in a decrease in both sensor response and signal-to-noise ratio; however, the response time and recovery degree improved. Two types of hybrid materials based on CNFs and MWCNTs were created using aerosol spraying to enhance the sensor behavior of CNFs. The obtained data confirm the dominant role of the thickness of CNF-based films and their density (in terms of distance between nearest carbon inclusions within the film) in sensor characteristics. The machine learning data used to describe the sensing behavior of two gases with opposite resistance changes when in contact with CNFs, namely NO₂ and NH₃, showed final accuracies of 92.13% on training data and 91.98% on validation data. Full article

Silicon (Si) is a promising high-capacity anode material for lithium–ion batteries but faces challenges such as severe volume fluctuations during cycles and the formation of unstable solid-electrolyte interphase films on the electrode surface. To address these limitations, we developed a bioinspired Si@C composite anode through polydopamine-mediated self-assembly of aromatic polyamide nanofibers and nano–Si, followed by controlled pyrolysis at 1000 °C under N₂. The resulting hierarchical architecture mimics the symbiotic root-nodule structure of legumes, featuring vascular bundle-like carbon frameworks and chemically bonded Si/C interfaces. The optimized composite delivers an initial capacity of 1107.0 mAh g⁻¹ at 0.1 A g⁻¹ and retains 580.0 mAh g⁻¹ after 100 cycles with 52.4% retention. The exceptional electrochemical properties arise from the optimized architecture and surface interactions. The nature-inspired carbon network minimizes ionic transport resistance via vertically aligned porous pathways while simultaneously boosting lithium–ion adsorption capacity. Furthermore, radially aligned graphitic ribbons are generated through controlled polyamide thermal transformation that effectively mitigates electrode swelling and maintains stable interfacial layers during cycling. Full article

The development of robust oxygen reduction reaction (ORR) catalyst with fast kinetics and good durability is significant for rechargeable zinc–air batteries (ZABs) but still remains a great challenge. Herein, inspired by the chain-like interconnective porous structure of plant luffa, an ORR catalyst of Co/CoCr₂O₄@ IPCF is fabricated, with Co and CoCr₂O₄ hybrid nanoparticles (NPs) embedding into interconnective porous carbon nanofibers (IPCF). Contributing to CoCr₂O₄ NPs stabilized Co active sites, the resulting ZABs assembled with Co/CoCr₂O₄@IPCF as an air cathode catalyst delivering sustainable cycling stability of 550 h, surpassing that of Co@IPCF based on ZABs (215 h). Also, the Co/CoCr₂O₄@IPCF has a high ORR performance with a half-wave potential (E_1/2) of 0.866 V in alkaline medium. The cycling stability originates from the IPCF carrier and the synergistic effect of Co NPs and CoCr₂O₄ NPs. The chain-like interconnective porous structure of the fibers provides more active sites and facilitates mass transfer to avoid the accumulation of OH⁻ and the exposure of H₂O₂, while the CoCr₂O₄ NPs can serve as a regulator for stabilizing the Co NPs electrochemical performance. Full article

Bionic synthesis technology has made significant breakthroughs in porous functional materials by replicating and optimizing biological structures. For instance, biomimetic titanium dioxide-coated carbon multilayer materials, prepared via biological templating, exhibit a hierarchical structure, abundant nanopores, and synergistic effects. Bionic mineralization further enhances microcapsules by forming a secondary inorganic wall, granting them superior impermeability, high elastic modulus, and hardness. Through techniques like molecular self-assembly, electrospinning, and pressure-driven fusion, researchers have successfully fabricated centimeter-scale artificial lamellar bones without synthetic polymers. In environmental applications, electrospun membranes inspired by lotus leaves and bird bones achieve 99.94% separation efficiency for n-hexane–water mixtures, retaining nearly 99% efficiency after 20 cycles. For energy applications, an all-ceramic silica nanofiber aerogel with a bionic blind bristle structure demonstrates ultralow thermal conductivity (0.0232–0.0643 W·m⁻¹·K⁻¹) across a broad temperature range (−50 to 800 °C). This review highlights the preparation methods and recent advances in biomimetic porous materials for practical applications. Full article

In recent years, electrospinning technology has sparked a revolution in the nanoengineering of gas-sensing materials. Nanofibers based on metal oxide semiconductors, carbon materials, or conductive polymers prepared by the electrospinning process have exhibited inspiring properties, including a large specific surface area, porous structure, and nice stability, with bright application prospects in advanced gas sensors. Meanwhile, the increasingly expanding applications of gas sensors, such as the Internet of Things (IoT), the food industry, disease diagnosis, etc., have raised higher sensor performance requirements. To further enhance the gas-sensing performance of nanofibers, the scheme of functionalized nanofiber strategies, either in electrospinning or post-treatment, has been proposed and verified. This review systematically summarized the nanostructures, gas-sensing properties, and functional mechanisms of modified nanofibers. Additionally, the perspectives and challenges regarding electrospun nanofibers for gas sensing were discussed. Full article

Electrochemical formation of ceria (mixed Ce₂O₃ and CeO₂) coatings on different types of screen-printed carbon electrodes (SPCEs) (based on graphite (C110), carbon nanotubes (CNT), single-walled carbon nanotubes (SWCNT), carbon nanofibers (CNF), and mesoporous carbon (MC)) were studied. Their potential applications as catalysts for various redox reactions and electrochemical sensors were investigated. The ceria oxide layers were electrodeposited on SPCEs at various current densities and deposition time. The morphology, structure, and chemical composition in the bulk of the ceria layers were studied by SEM and EDS methods. XRD was used to identify the formed phases. The concentration, chemical composition and chemical state of the elements on the surface of studied samples were characterized by XPS. It was established that the increase of the concentration of CeCl₃ in the solution and the cathode current density strongly affected the surface structure and concentration (relation between Ce³⁺ and Ce⁴⁺, respectively) in the formed ceria layers. At low concentration of CeCl₃ (0.1M) and low values of cathode current density (0.5 mA·cm⁻²), porous samples were obtained, while with their increase, the ceria coatings grew denser. Full article

Chlorpheniramine maleate (CPM) is a first-generation antihistamine that is frequently used to treat allergic reactions. However, excessive consumption presents potential health risks. Therefore, it is crucial to develop a quick and precise technique for identifying CPM levels. In this study, nickel cobalt phosphide (NiCoP), a binary metal phosphide, was successfully incorporated into carbon nanofibers. This involved creating a pore structure by adding polyvinylpyrrolidone (PVP) as a pore-forming template to a polyacrylonitrile (PAN) substrate via electrostatic spinning. An innovative electrochemiluminescent sensor for CPM detection was constructed using NiCoP/PVP/PAN carbon nanofibers (NiCoP/PVP/PAN/CNFs). Under optimal conditions, the electrochemical behavior of CPM was studied using NiCoP/PVP/PAN/CNF-modified working electrodes. These findings demonstrate that the three-dimensional porous network architecture of NiCoP/PVP/PAN/CNFs enhances the conductive properties of the material. Consequently, an electrochemical optical sensor fabricated using this structure exhibited remarkable performance. The linear detection range of the sensor was 1 × 10⁻⁸–7 × 10⁻⁵ mol/L, and the detection limit was 7.8 × 10⁻¹⁰ mol/L. When human urine and serum samples were examined, the sensor was found to have a high recovery rate (94.35–103.36%), which is promising for practical applications. Full article

A novel composite material consisting of cerium dioxide (CeO₂), silica (SiO₂), and mesoporous carbon (CMK-3) was developed for supercapacitor electrodes. The composite’s synthesis involved a high-surface-area porous carbon combined with CeO₂ and SiO₂. The resulting material was characterized by a high specific capacitance due to its mesoporous structure and enhanced dispersion CeO₂ and SiO₂. The effects of different types of CeO₂ and SiO₂ are also discussed. Both CeO₂ and SiO₂ components offer advantages such as abundance, low costs, and excellent catalytic properties. The composite’s structure improves CeO₂ nanofiber (CeO₂ NF) dispersion and reduces impedance through rapid redox reactions. The influence of the CeO₂/SiO₂/CMK-3 ratio on specific capacitance was investigated. The optimized composite electrode demonstrated a significantly improved specific capacitance, 2.6 times higher than that of the pristine mesoporous carbon electrode. This work highlights the potential of CeO₂/SiO₂/CMK-3 composites for energy storage applications and underscores the importance of optimizing component ratios and morphology for improved supercapacitor performance. Full article

To comparatively study the effects of cold plasma activation and chemical treatment on the adsorption capacities of biomass carbon nanofiber membranes (BCNMs), microcrystalline cellulose (MCC) and chitosan (CS) were used to fabricate porous BCNMs by electrospinning and carbonization. Two modification methods, including oxygen (O₂) plasma activation and chemical treatment using nitric acid (HNO₃), sulfuric acid (H₂SO₄), hydrogen peroxide (H₂O₂), and urea, were further employed to enhance their adsorption performance. Various carbonyl group (C=O), ether bond (C-O), carboxyl group (O-C=O) and pyridinic nitrogen (N), pyrrolic N, and quaternary N functional groups were successfully introduced onto the surface of the BCNMs by the two methods. The BCNM-O₂ showed optimal formaldehyde absorption capacity (120.67 mg g⁻¹), corresponding to its highest contents of N, O-containing functional groups, and intact network structure. However, chemical treatment in strong acid or oxidative solutions destructed the microporous structures and changed the size uniformity of fibers in the BCNMs, resulting in a decline in formaldehyde adsorption capacity. A synergistically physical–chemical adsorption took place during formaldehyde adsorption by the modified biomass nanofiber membranes, due to the coexistence of suitable functional groups and porous structures in the membranes. Full article

Rechargeable metal chloride batteries, with their high discharge voltage and specific capacity, are promising for next-generation sustainable energy storage. However, sluggish solid-to-gas conversion kinetics between solid metal chlorides and gaseous Cl₂ cause unsatisfactory rate capability and limited cycle life, hindering their further applications. Here we present a rechargeable aluminum-chlorine (Al-Cl₂) battery that relies on a confined chlorine conversion chemistry in a molten salt electrolyte, exhibiting ultrahigh rate capability and excellent cycling stability. Both experimental analysis and theoretical calculations reveal a reversible solution-to-gas conversion reaction between AlCl₄⁻ and Cl₂ in the cathode. The designed nitrogen-doped porous carbon cathode enhances Cl₂ adsorption, thereby improving the cycling lifespan and coulombic efficiency of the battery. The resulting Al-Cl₂ battery demonstrates a high discharge plateau of 1.95 V, remarkable rate capability without capacity decay at different rates from 5 to 50 A g⁻¹, and good cycling stability with over 1200 cycles at a rate of 10 A g⁻¹. Additionally, we implemented a carbon nanofiber membrane on the anode side to mitigate dendrite growth, which further extends the cycle life to 3000 cycles at an ultrahigh rate of 30 A g⁻¹. This work provides a new perspective on the advancement of high-rate metal chloride batteries. Full article

Carbon-based microwave absorption materials have garnered widespread attention as lightweight and efficient wave absorbers, emerging as a prominent focus in the field of functional materials research. In this work, FeNi₃ nanoparticles, synthesized in situ within graphite interlayers, were employed as catalysts to grow carbon nanofibers in situ via intercalation chemical vapor deposition (CVD). We discovered that amorphous carbon nanofibers (CNFs) can exfoliate and separate highly conductive graphite nanosheets (GNS) from the interlayers. Meanwhile, the carbon nanofibers eventually intertwine and encapsulate the graphite nanosheets, forming porous hybrids. This process induces significant changes in the electrical conductivity and electromagnetic parameters of the resulting GNS/CNF hybrids, enhancing the impedance matching between the hybrids and free space. Although this process slightly reduces the microwave loss capability of the hybrids, the balance between these effects significantly enhances their microwave absorption performance, particularly in the K_u band. Specifically, the optimized GNS/CNF hybrids, when mixed with paraffin at a 30 wt% ratio, exhibit a maximum microwave reflection loss of −44.1 dB at 14.6 GHz with a thickness of 1.5 mm. Their effective absorption bandwidth, defined as the frequency range with a reflection loss below −10 dB, spans the 12.5–17.4 GHz range, covering more than 80% of the K_u band. These results indicate that the GNS/CNF hybrids prepared via intercalation CVD are promising candidates for microwave absorption materials. Full article

Phase change fibers (PCFs) can effectively store and release heat, improve energy efficiency, and provide a basis for a wide range of energy applications. Improving energy storage density and preserving flexibility are the primary issues in the efficient manufacture and application development of PCFs. Herein, we have successfully fabricated a suite of flexible PCFs with high energy storage density, which use hollow carbon fibers (HCFs) encapsulated phase change materials (PCMs) to provide efficient heat storage and release, thereby enhancing energy efficiency and underpinning a broad range of energy applications. The flexible HCF/LA PCFs with high energy density were made by impregnating a small molecule LA solution, whereas the precursor of the PAN/ZIF-67 composite fibers was created by electrospinning. These PCFs have a high loading capacity for lauric acid (LA), demonstrating a 92% load percentage and a 153 J g⁻¹ phase change enthalpy value. The effects of doping quantity (ZIF-67), fiber orientation, pre-oxidation treatment, and particle size on the morphological and structural characteristics of HCFs, as well as the impact of HCFs’ pore structure on PCM encapsulation, were investigated. It was found that the oriented fiber structure serves to reduce the likelihood of fracture and breakage of precursor fibers after carbonization, whilst the gradient pre-oxidation can maintain the original fiber morphology of the fibers after carbonization. These findings establish a solid theoretical foundation for the design and production of high-performance flexible porous carbon nanofiber wiping phase change composites. Full article

Needle-like CoO nanowires have been successfully synthesized by a facile hydrothermal process on an electrospun carbon nanofibers substrate. The as-prepared sample mesoporous CoO nanowires aligned vertically on the surface of carbon nanofibers and cross-linked with each other, producing loosely porous nanostructures. These hybrid composite electrodes exhibit a high specific capacitance of 1068.3 F g⁻¹ at a scan rate of 5 mV s⁻¹ and a good rate capability of 613.7 F g⁻¹ at a scan rate of 60 mV s⁻¹ in a three-electrode cell. The CoO NWs@CNF//CNT@CNF asymmetric device exhibits remarkable cycling stability and delivers a capacitance of 79.3 F/g with a capacitance retention of 92.1 % after 10,000 cycles. The asymmetric device delivers a high energy density of 37 Wh kg⁻¹ with a power density of 0.8 kW kg⁻¹ and a high power density of 16 kW kg⁻¹ with an energy density of 23 Wh kg⁻¹. This study demonstrated a promising strategy to enhance the electrochemical performance of flexible supercapacitors. Full article