Polyaniline Nanofibers Research Articles

Unveiling the Role of Filler Characteristics in Enhancing the High-Voltage Performance of Succinonitrile-Based Solid-State Lithium-Metal Batteries.

For exploiting high-energy lithium-metal batteries, it is of utmost importance to develop electrolytes that possess exceptional ionic conductivity and an extensive electrochemical stability range. In this study, 3D PAN nanofibers and polymer electrolytes incorporating various inorganic fillers with different Lewis acid-base properties were fabricated. PAN@Al-SSE exhibits exceptional ionic conductivity (0.48 mS·cm-2 at room temperature), a high Li+ transference number (0.41), and a wide electrochemical window (5.26 V). The device is able to operate stably in Li symmetric cells for more than 1000 h under a potential of 0.03 V under a current density of 0.2 mA·cm-2. Besides, the groundbreaking technology equips high-voltage Li-LiCoO2 solid-state batteries with exceptional cycling performance (91.3% and 82.1% retention after 100 cycles at 0.2 and 1 C, respectively) at room temperature. Mechanistic studies indicate that the Lewis acid-base properties of surface fillers are instrumental and crucial to form a stable solid-electrolyte interphase layer. γ-Al2O3, in particular, with more Lewis acid sites, ensures the dissociation of LiTFSI and induces the excessive decomposition and polymerization of succinonitrile. There exists an equilibrium effect between dissociation and polymerization in a succinonitrile-based solid electrolyte, which plays a critical role in improving the manifestation of succinonitrile-based solid-state lithium cells, especially under high-voltage conditions.

Ti3C2Tx MXene‐Polyaniline Nanocomposite as an Adsorbent in Microextraction by Packed Sorbent for the Analysis of Parabens in Water and Juice Samples

ABSTRACTHerein, a novel Ti3C2Tx MXene and polyaniline nanocomposite is successfully synthesized and used for the highly efficient extraction of parabens. Polyaniline (PANI) nanofibers have formed a porous and peculiar π–π conjugated structure on hydrophilic MXene sheets, providing numerous adsorption sites for microextraction of analytes with moderate polarities such as parabens. The method is simple and sensitive, using microextraction by packed sorbent coupled with a high‐performance liquid chromatography‐ultraviolet detector. Under the optimal conditions, the method provides suitable preconcentrating factors of 28–35, ultrahigh sensitivity with low limits of detection of 0.3–0.5 µg/L, wide linearity of 0.3.0–200 µg/L with coefficients of determination ≥ 0.9983, and satisfactory precision with relative standard deviations ≤ 10.7%. The outstanding performance has been confirmed in well water and orange juice samples, with recoveries in the range of 93.1%–101.2% for water and 90.6%–103.4% for orange juice samples, respectively.

High-Energy-Density Lithium–Sulfur Battery Based on a Lithium Polysulfide Catholyte and Carbon Nanofiber Cathode

Li–S batteries are promising large-scale energy storage systems but currently suffer from performance issues; a major reason is the dissolution of polysulfides in electrolytes. To this end, we report a high-energy-density Lithium–Sulfur (Li–S) battery that combines a catholyte and a sulfur-free carbon nanofiber (CNF) cathode. The cathode was synthesized by carbonizing binder-free polyacrylonitrile (PAN) nanofibers, affording a high surface area. In the catholyte, added polysulfides acted as both conductive Li salts and active materials. Investigating the electrochemical performance of this concept in both Swagelok- and pouch-type cells afforded energy densities exceeding 3 mAh cm−2 at a discharge rate of 0.1 C. This combination could also be utilized in high-capacity pouch cells with capacities of up to 250 mAh g−1. Both cell types exhibited good cycle performance. Adding LiNO3 to the electrolyte suppressed the redox shuttle reactions. Moreover, the cathode being binder-free increased the energy density and simplified cathode fabrication. Characterizing the cathode before and after cycling revealed that deposition was reversible, and that cell reactions at least partially formed sulfur as the end product, resulting in high sulfur amounts in the cell. We expect our concept to greatly aid in the development of practically applicable Li–S cells.

A novel multifunctional photocatalytic membrane based on β-FeOOH for oily wastewater purification

In order to deal with the environmental pollution caused by complex oily wastewater, it is necessary to develop filtration membrane materials. However, significant challenges such as poor effect of emulsion separation, limited functionality, and susceptibility to membrane fouling require urgent resolution. Here, we successfully prepared a β-hydroxyl iron oxide/polydopamine-polyethylenimine/polyacrylonitrile (β-FeOOH/PDA-PEI/PAN) nanofiber membrane for treatment of complex wastewater by growing PDA-PEI on a blow-spinning PAN nanofiber membrane and decorating the membrane with β-FeOOH. The porous structure and the large number of hydrophilic groups greatly increase the hydrophilicity of the membrane and give the membrane high permeation fluxes (11531.26 L m−2 h−1) for surfactant-free kerosene-in-water emulsion. The loaded β-FeOOH nanorods increase the roughness of the membrane surface, which enhances the underwater superoleophobic ability of the membrane, and promotes the demulsification of the emulsion and makes it have high separation efficiency of 99.48 % for surfactant-stabilized kerosene-in-water emulsion. In addition, the β-FeOOH/PDA-PEI/PAN also exhibited high organic dye removal efficiency (99.38 %) due to the presence of β-FeOOH. The synergistic effect of low oil adhesion and photocatalysis enhances the antifouling and self-cleaning performances of the material. Significantly, the multifunctional membrane also shows exceptional oil/water separation ability and good stability. The presented synergistic strategy of β-FeOOH/PDA-PEI/PAN membrane materials represents a prospective candidate for the treatment of complex wastewater.

Room temperature in situ growth of fluorinated covalent organic framework on electrospun nanofibers for efficient detection of benzoylurea insecticide residue in water samples

The accurate detection of benzoylurea insecticides (BUs) residues is vital for the environment and human health. In this work, a room-temperature synthesis strategy was developed to fabricate the covalent organic framework (COF)–polyacrylonitrile (PAN) nanofibers composite by an electrospinning technique. The COF was functionalized on PAN nanofibers via in situ polymerization of 1,3,5-tris(4-aminophenyl)triazine (TAPT) and 2,3,5,6-tetrafluoroterephthaldehyde (TFTA). The obtained TAPT-TFTA@PAN nanofibers showed a porous structure, high surface area, good crystallinity and excellent extraction efficiency to BUs. A sensitive method combining dispersive solid-phase extraction (DSPE) using TAPT-TFTA@PAN nanofibers as an adsorbent with liquid chromatography–ultraviolet detector was developed for trace analysis of four BUs in environment water samples. This method achieved a wide linear range of 0.5–200 ng·mL−1 for triflumuron and hexaflumuron, and of 0.5–150 ng·mL−1 for teflubenzuron and fluazuron. The limits of detection (S/N = 3) for four BUs ranged from 0.11 to 0.42 ng·mL−1. The accuracy of the proposed method was validated by measuring trace BUs in the spiked water samples with recoveries in the range of 98.3 %∼125.3 %. The results demonstrated that the TAPT-TFTA@PAN nanofibers have great potential as an extractant for effective enrichment of benzoylurea insecticide from complex water samples.

Thermal hysteresis enhancement and dispersion thermal stability in paraffin actuators: Comparison of pan-nanofibers vs metal oxide nanoparticles use

In this research, the possibility of thermal property enhancement of paraffin actuators with nanofiber and metal oxide nanoparticle addition was experimentally evaluated. Besides pure paraffin compound, paraffin mixed with the CuO, Fe3O4, ZnO, Al2O3, and electrospun polyacrylonitrile (PAN) nanofiber nanoparticles were used, and a significant hysteresis improvement at first-level measurement was observed as 24.6, 26.2, 20.0, 29.2, and 30.8 % sequentially for the samples respectively compared with pure paraffin. Thermal dispersion stability of the nanocomposites was comprehended via computer tomographic (CT) investigation. The excessive precipitation of CuO, Fe3O4, and ZnO particles in the paraffin nanocomposite was observed. Precipitation of PAN Nanofiber- and Al2O3-Paraffin nanocomposite was not visually detectable via CT throughputs. The effect of thermal dispersion stability on the hysteresis performance of the nanocomposites was also investigated to ensure long-term consistent hysteresis performance advantages in paraffin actuators. Thermal dispersion stability effect on hysteresis performance of paraffin actuators with CuO, Fe3O4, ZnO, Al2O3, and PAN nanofiber nanocomposite paraffin compounds showed losses as 14.3, 14.6, 5.8, 4.3 and 2.2 % sequentially for the samples respectively.

Exploring the potential of SnSe/PANi composite counter electrodes for improved efficiency in dye-sensitized solar cells

This paper investigates the synthesis and characterization of novel counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), focusing on composite polyaniline (PANi) nanofibers integrated with tin selenide (SnSe). Three CEs, namely SnSe, PANi, and their composite, were prepared via facile hydrothermal and cyclic voltammetry methods and compared with a standard platinum (Pt) CE. The efficiencies obtained were 4.20 %, 5.63 %, 8.39 %, and 7.72 % for SnSe, PANi, SnSe/PANi, and Pt CEs, respectively. The improved efficiencies, particularly in the case of the SnSe/PANi composite, were attributed to increased short-circuit density of the composite sample. The materials and devices prepared in this study are characterized using various methods including FESEM, TEM, XRD, Raman and FTIR spectroscopies, EIS, Tafel, OCVD, IPCE and etc to support our proposed CE structure. Our findings demonstrate the promising potential of SnSe/PANi composite CEs in enhancing the performance and affordability of DSSCs.

Advancement of Graphite-Clay Composite Electrodes via Different Compositions to Improve the Synergetic Matrix Effect Towards General Electroanalytical and Energy Storage Applications

Modern electrode technology trends for enhancing multifunctional electrodes, prioritizing energy storage and electroanalytical prospects. This study anticipates fabricating electrodes by incorporating cement and colloidal graphite, to improve the performance via synergetic interactions of the composite matrix. Graphite-montmorillonite-cement ternary composite electrode (GMMTCeCE) and graphite-colloidal graphite-montmorillonite-cement quaternary composite electrode (GCGMMTCeCE) are fabricated, as two types of electrodes. GMMTCeCE reflects the lowest peak-to-peak separation in Ce3+/Ce4+ (0.098 V), greater sensitivity towards [Fe(CN)6]4- (2.68 A·m·mol-1) and [Fe(CN)6]3- (2.64 A·m·mol-1), showing comparatively better performance in analyte detection than GCGMMTCeCE. Multilayered polyaniline (PANI) nanofibers network, which is unique in GMMTCeCE electropolymerization, accounts for very low serial (0.38 Ω) and charge transfer (0.59 Ω) resistances, while densely packed nanofibers of PANI in GCGMMTCeCE is responsible for the lowest ohmic resistance (1.31 Ω). Supercapacitor device fabricated by PANI-GMMTCeCE, achieved higher capacitance (1,002 F·g-1 at 5 mV·s-1) and showed greater cyclic stability, in contrast to relatively lower specific capacitance (685 F·g-1 at 5 mV·s-1) attained by PANI-GCGMMTCeCE, demonstrates the superiority of the supercapacitor of GMMTCeCE over GCGMMTCeCE for energy-storage purposes. Therefore, GMMTCeCE outperformed GCGMMTCeCE in electroanalysis and energy storage, confirming better synergetic interactions of the ternary composite matrix over the quaternary one. Besides, further improvements in graphite-clay composite matrix properties facilitate the advancement of electrochemical sensors and supercapacitor devices.

Cotton-like antibacterial polyacrylonitrile nanofiber-reinforced chitosan scaffold: Physicochemical, mechanical, antibacterial, and MC3T3-E1 cell viability study

Bio-scaffolds, while mimicking the morphology of native tissue and demonstrating suitable mechanical strength, enhanced cell adhesion, proliferation, infiltration, and differentiation, are often prone to failure due to microbial infections. As a result, tissue engineers are seeking ideal scaffolds with antibacterial properties. In this study, silver nanoparticles (AgNPs) were integrated into cotton-like polyacrylonitrile nanofibers via a polydopamine (PDA) interlayer (Ag@p-PAN). These Ag@p-PAN nanofibers were then incorporated into the chitosan (CS) matrix, developing an antibacterial CS/Ag@p-PAN composite scaffold. The composite scaffold features an interconnected porous morphology with fiber-infused pore walls, improved water absorption and swelling properties, a controlled degradation profile, enhanced porosity, better mechanical strength, strong antibacterial properties, and excellent MC3T3-E1 cell viability, adhesion, proliferation, and infiltration. This study presents a novel method for reinforcing CS-based scaffolds by incorporating bioactive nanofibers, offering potential applications in tissue engineering and other biomedical fields.

Electrospun polyacrylonitrile nanofiber composites integrated with Al-MOF/mesoporous carbon for superior CO2 capture and VOC removal

Electrospun PAN nanofiber composites with integrated Metal-Organic Frameworks (MOFs) and mesoporous carbon (MPC) offer an efficient solution for CO2 capture and hydrocarbon removal. In this study, we synthesized a series of NH2-MIL-101(Al)@MPC composites using a solvothermal method and incorporated them into PAN nanofibers via electrospinning. The composites were characterized by FTIR, XRD, FESEM, XPS, mechanical properties and TGA, showing enhanced surface area and pore structure. NH2-MIL-101(Al) exhibited a BET surface area of 933.14 m2/g, crucial for selective absorption. The PAN/MOF@MPC nanofibers demonstrated improved mechanical properties and achieved a CO2 uptake of 6.35 mmol g−1 at 298 K and 0.55 bar. Additionally, the modified nanofibers demonstrated excellent static and dynamic adsorption capacities for volatile organic compounds (VOCs) like acetone and benzene. This study highlights the synergistic effects of combining MOFs and MPCs within electrospun nanofibers, resulting in materials with enhanced adsorption efficiency and mechanical stability. The work presents a novel approach by integrating MOF@MPCs into electrospun PAN nanofibers, significantly enhancing CO2 capture and VOC removal. This innovative combination not only improves the adsorption performance but also advances the mechanical properties of the nanofibers, showcasing a new strategy for developing high-performance materials for environmental remediation. The results offer strong potential for real-world applications in air purification and carbon sequestration.

MnO2‐Infused PAN Carbon Nanofibers Synthesized via Electrospinning for Enhanced Supercapacitor Performance

AbstractSupercapacitors (SCs) are crucial for high‐performance energy storage, offering high power density, swift charge–discharge rates, and durability. The enhancement of their performance hinges on the development of advanced electrode materials. This study presents an innovative method involving polyacrylonitrile (PAN) nanofibers adorned with manganese dioxide (MnO₂) nanoparticles (NPs), created through electrospinning and subsequent thermal treatment. This synergy exploits the extensive surface area and electrical conductivity of PAN nanofibers along with the substantial capacitance of MnO₂. The MnO₂‐coated PAN nanofibers reached an impressive specific capacitance of 247 F g−1 at a scan rate of 10 mVs−1, markedly boosting the efficacy of all‐solid‐state asymmetric SCs. The SCs, incorporating a polyvinyl alcohol (PVA)/potassium hydroxide (KOH) gel electrolyte, exhibited an energy density of 8.2 Wh kg−1 at a power density of 700 W kg−1, preserving 80.4% of their original capacitance after 5000 cycles. This research is pioneering in combining MnO₂ with PAN nanofibers, marking a significant leap forward in supercapacitor technology with enhanced energy storage capacity and prolonged stability. These findings underscore the promise of these composite materials in future energy storage solutions.

Advanced and sustainable EMI shielding composites: Natural rubber-nitrile rubber blends enhanced with hydrothermally synthesized Polyaniline Nanofibers and spinel strontium ferrites

Conductive fillers, such as metals and carbon compounds, often exhibit lower compatibility with polymer matrices, leading to agglomeration phenomena that negatively impact the processing and performance of composites. Polyaniline (PANI) nanofibers, with their high conductivity, rapidly create conductive pathways upon contact, reducing current leakage and dielectric loss in composites. To address the compatibility challenges between fillers and matrices, this study adopts a simple, cost-effective approach for synthesizing highly efficient EMI shielding composites. Specifically, we employ hydrothermal synthesis to enhance the properties of PANI nanofibers and spinel strontium ferrites, significantly improving their performance as filler particles. By modifying the morphology of the conductive fillers and incorporating magnetic particles wrapped with an insulating polymer layer, we enhance filler-matrix compatibility. Notably, the synthesized system is a composite made of natural rubber, highlighting its relevance and importance in the current era. This approach not only improves compatibility but also leverages the sustainable properties of natural rubber, making it a significant advancement in the field of EMI shielding materials. In this paper, we report a flexible EMI shielding composite with efficient EM wave absorption, prepared using a natural rubber-nitrile rubber blend as the matrix, and hydrothermally synthesized improves polyaniline nanofibers and spinel strontium ferrite as functional fillers. The shielding efficiency (SET) increases up to 36 dB with different PANI-SrFe2O4wt percentages. This demonstrates the potential of composite for high-performance applications.

Optimisation of Electrospinning Parameters for High-Strength Oriented Pan Nanofibre Mats

Abstract This study explores the optimisation of electrospinning parameters to enhance the strength and orientation of polyacrylonitrile (PAN) nanofibre mats, which are pivotal in filtration applications and other areas requiring high-strength, uniformly distributed nanofibres. The focus is on the electrospinning process, particularly on a rotating drum collector, which is instrumental in determining the morphology of nanofibres. Key process variables, including the distance between the collector and the syringe, feed rate, applied voltage, and polymer concentration, have been meticulously examined to understand their influence on the physical properties of PAN nanofibres. Our findings indicate that parameters such as voltage, collector-to-syringe distance, and drum rotation speed (RPM) significantly impact the mechanical performance of the nanofibre mats. The optimised electrospinning conditions produced PAN nanofibre mats with tensile strengths ranging from 1.61 MPa to 21.78 MPa, demonstrating a notable improvement in strength due to controlled fluid dynamics and expulsion of polymer solution during the process.

Capacitive behaviors for surface-sulfonated polyaniline nanofibers in different acidic electrolytes

Abstract Unique surface-sulfonated polyaniline nanofibers (PANI-S) were fabricated through one-pot polymerization to evaluate the feasibility of their applications as electrode materials for high-performance supercapacitors that can be operated in relatively weak acidic electrolytes. Benefiting from the self-doping effect and improved dispersion in aqueous solution for the nanofibers, as well as the effective buffering function of the electrolyte, the PANI-S exhibits excellent capacitive performance across a broad pH value range in acidic electrolytes. More clearly, the specific capacitance of the PANI-S remains remarkably stable, ranging from 752.4 to 754.4 F g−1 at a scan rate of 5 mV s−1 and from 575.4 to 536.8 F g−1 at a current density of 1 A g−1, as the pH value of the electrolyte varies from 0 to 6. However, the capacity retention rate of PANI-S gradually decreases from 79.2% to 37.2% as the current density increases from 1 A g−1 to 20 A g−1, with the pH of the buffered solution increasing from 0 to 6. The excellent electrochemical activity in low acidic electrolytes for PANI nanofibers can be attributed to the compensation effects of the self-doped local proton reservoir.

Zwitterion Modified Polyacrylonitrile Fiber Separator for Long‐Life Zinc‐Ion Batteries

AbstractThe major challenges of aqueous zinc‐ion batteries (ZIBs) are the dendrite formation and the passivation of zinc metal anode, which restrict their practical applications. Herein, polyacrylonitrile (PAN) and zwitterionic surfactant (Sulfobetaine methacrylate, SBMA) are combined as a precursor to design a modified PAN nanofiber separator by electrospinning. SBMA with sulfonate group [SO3−] can alter the physical property of the precursor solution and electrostatic field during the electrospinning process. Besides, it can regulate the zinc ions crossing and homogenize the electric field by minimizing the zinc ion concentration polarization on the zinc foil surface due to the polar group. As a result, Zn symmetric cells with PAN@SBMA separators show long‐term stability (up to 1700 h), which outdistances the cell with GF‐D (only up to 50 h) under current density at 1 mA cm−2. Meanwhile, the Zn//PAN@SBMA//NH4V4O10 full cells have high specific capacity (236 mAh g−1) and excellent long‐term durability with 84.2% capacity retention after 2000 cycles at 5 A g−1. This work illustrates an easy and effective way to design a high ion transference number and functional PAN‐based separator for regulating Zn2+ deposition for the development of high‐performance ZIBs.

Sensor parameters and adsorption behaviour of rhodamine-based polyacrylonitrile (PAN) nanofiber against dichloromethane vapour

This study is focused on the determination of sensor and adsorption parameters ofrhodamine-based polyacrylonitrile (PAN) nanofiber during the dichloromethane vapour exposure due to a very limited investigation of the rhodamine-based PAN nanofiber sensor. Quartz crystal microbalance (QCM) measurement system is employed to monitor the sensor response to dichloromethane vapour. This nanofiber sensor demonstrates a highly sensitive, stable, reproducible response and concentration dependence behaviour. A good stability, with an excellent recovery occurred. Sensor parameters such as the limit of detection (153 ppm), the limit of quantification (465 ppm), the sensitivity (0.0215 Hz/ppm), response (2 s) and recovery (3 s) times are determined using QCM measurement results. Pseudo first-order and Elovich adsorption models have proved that dichloromethane vapours are adsorbed bythis nanofiber sensor andthe amount of vapour adsorption rate is increased when the concentration of dichloromethane vapour increases.Owing to its achieved sensor parameters, high adsorption feature and simple fabrication process with a low cost, this proposed sensing device is expected to be a promising alternative for monitoring dichloromethane vapour sensing application at room temperature.

Visual Detection of Dopamine with CdS/ZnS Quantum Dots Bearing by ZIF-8 and Nanofiber Membranes.

Dopamine (DA) is a widely present, calcium cholinergic neurotransmitter in the body, playing important roles in the central nervous system and cardiovascular system. Developing fast and sensitive DA detection methods is of great significance. Fluorescence-based methods have attracted much attention due to their advantages of easy operation, a fast response speed, and high sensitivity. This study prepared hydrophilic and high-performance CdS/ZnS quantum dots (QDs) for DA detection. The waterborne CdS/ZnS QDs were synthesized in one step using the amphiphilic polymer PEI-g-C14, obtained by grafting tetradecane (C14) to polyethyleneimine (PEI), as a template. The polyacrylonitrile nanofiber membrane (PAN-NFM) was prepared by electrospinning (e-spinning), and a metal organic frame (ZIF-8) was deposited in situ on the surface of the PAN-NFM. The CdS/ZnS QDs were loaded onto this substrate (ZIF-8@PAN-NFM). The results showed that after the deposition of ZIF-8, the water contact angle of the hydrophobic PAN-NFM decreased to within 40°. The nanofiber membrane loaded with QDs also exhibited significant changes in fluorescence in the presence of DA at different concentrations, which could be applied as a fast detection method of DA with high sensitivity. Meanwhile, the fluorescence on this PAN-NFM could be visually observed as it transitioned from a blue-green color to colorless, making it suitable for the real-time detection of DA.

Polymer concentration adjustment for homogeneous carbon nanofibers precursors

Introduction. Carbon nanofibers CNFs have emerged as an important material in many advanced applications, especially those related to high electrical conductivity. Objectives. The primary objective of this study was to prepare a homogeneous CNFs’ precursor (Polyacrylonitrile PAN nanofibers) with improved graphitization through controlling one of the solution parameters, that is, polymer concentration. Methods. Precursors of PAN nanofibers with the addition of multi-walled carbon nanotubes MWCNTs were prepared with two concentrations of 8% and 10% w/v PAN/MWCNTs to adjust the insertion and uniform distribution of MWCNTs within the PAN nanofibers. Field emission scanning electron microscopy FESEM was used to evaluate the morphology of the electro spun nanofibers and uniformity of the MWCNTs distribution within the PAN nanofibers. Fourier transform infrared spectroscopy FTIR was also conducted to notice the interaction between MWCNTs and PAN to yield precursor with better graphitization characteristics. Results. FESEM results revealed more uniformity and homogeneity in the precursor structure with increasing PAN/MWCNTs concentration from 8% to 10% w/v. FTIR results showed increased intensity of the characteristic peaks of PAN and a new peak emerged at approximately 659 cm−1(C=C) which is potentially formed by interactions with MWCNTs and might be associated with cross-linking. Conclusion. Increased PAN/MWCNTs concentration from 8% to 10% w/v improved the insertion of MWCNTs inside PAN nanofibers and FTIR indicated the interactions between the added MWCNTs and PAN in the precursor with better graphitization characteristics.

Isotropically Polarized Bipiezoelectric Polyacrylonitrile-Poly(vinylidene Fluoride) Advanced Triboelectric Nanogenerator for Operation in High-Humidity Environments.

Conventional hybrid piezo-triboelectric nanogenerators (PTNGs) have potential applications as energy supply devices for microelectronic devices, but their low power density and unstable performance under high-humidity conditions are challenges that need to be solved. Here, we report a novel flexible hybrid bifiezo-triboelectric nanogenerator (Bi-PTNG) based on isotropic polarization design of piezoelectric PVDF and PAN nanofiber membranes, which greatly improves power density of devices and performances in high-humidity conditions. The performance enhancement mechanism of the Bi-PTNG was investigated by model analysis, experimental measurements, and simulations. The results showed that the power density output of Bi-PTNG increased by approximately 88% compared to that of a depolarized PAN/PVDF-based triboelectric nanogenerator (TENG). The application studies demonstrated that a 2 × 2 cm2 Bi-PTNG can be directly used to run more than 120 commercial LEDs, and this highly flexible and breathable all-fiber device can be integrated into clothing or insoles to monitor human movement in high-humidity conditions. This work not only provides an effective strategy for enhancing the power output of TENGs and advancing their practical applications but also offers robust guidance for the material selection and optimization of the polarization direction in such nanogenerators.

Bio-metal organic framework functionalized nanofibers as efficient proton-conducting for proton exchange membrane

A membrane with a low methanol permeability and high proton conductivity (σp) is essential for the effective operation of a direct methanol-based fuel cell. Herein, a bio-metal organic framework was prepared with natural α-amino acids as ligands and then combined with hydrolyzed polyacrylonitrile (PAN) nanofibers (AA-MOF@PAN). The resulting nanocomposite membranes were subsequently integrated into a Nafion matrix (AA-MOF@PAN/Nafion). The –NH2 groups on AA-MOF@PAN interact with –SO3H groups on Nafion, forming long-range acid-base pairs along the interface between the matrix and nanofibers. This interaction creates abundant proton-conducting sites for proton exchange membrane. Notably, the AA-MOF@PAN-4h/Nafion membrane demonstrated an exceptional proton conductivity (σp) of 0.25 S cm−1 and a higher power density of 117.61 mW cm−2 compared to the recast Nafion membrane. This study offers valuable insights into the three-dimensional ordered design of a natural α-amino acids as a proton transfer sites and highlighting their potential applications in proton exchange membranes.