Polyacrylonitrile Matrix Research Articles

A flexible wearable sensor based on improving the piezoelectric layer performance of sandwich structures with micro-/mesopores for communication with the deaf-mute

Layered H-UiO-66@IL composites with both intraparticle micropores, interparticle mesopores, and multiple active sites were prepared. A key aspect of the technique was the addition of deionized water during solvothermal synthesis, which rapidly nucleated layered nanoparticles. A multifunctional, flexible, and stable polyacrylonitrile (PAN)-based membrane was successfully constructed by incorporating H-UiO-66 nanoparticles, modified by ionic liquid (1-allyl-3-butylimidazole tetrafluoroborate), into polymers with macromolecular chains under mild, controlled conditions. The resulting film exhibited excellent dielectric, ferroelectric, and mechanical properties due to the multilayer fiber design. Furthermore, the PAN matrix showed a higher content (97.41 %) of planar zigzag conformations, enhancing the piezoelectric properties. The composite film demonstrated ultra-high sensitivity (10.98 V/N) and an ultra-low detection limit of 3.5 × 10⁻⁴ N. In addition, the film passed 1,800-cycle stability tests and maintained its initial output value across various environmental conditions. This flexible piezoelectric sensor shows significant potential for aiding deaf and mute individuals in sign language or breathing communication.

BioMOF@PAN Mixed Matrix Membranes as Fast and Efficient Adsorbing Materials for Multiple Heavy Metals' Removal.

Heavy metal ions are a common source of water pollution. In this study, two novel membranes with biobased metal-organic frameworks (BioMOFs) embedded in a polyacrylonitrile matrix with tailored porosity were prepared via nonsolvent induced phase separation methods and designed to efficiently adsorb heavy metal ions from oligomineral water. Under optimized preparation conditions, stable membranes with high MOF loading up to 50 wt % and a cocontinuous sponge-like morphology and a high water permeability of 50-60 L m-2 h-1 bar-1 were obtained. The tortuous flow path in combination with a low water flow rate guarantees maximum contact time between the fluid and the MOFs, and thus a high heavy metal capture efficiency in a single pass. The performances of these BioMOF@PAN membranes were investigated in the dynamic regime for the simultaneous removal of Pb2+, Cd2+, and Hg2+ heavy metals from aqueous environments in the presence of common interfering ions. The new composite adsorbing membranes are capable of reducing the concentration of heavy metal pollutants in a single pass and at much higher efficiency than previously reported membranes. The enhanced performance of the mixed matrix membranes is attributed to the presence of multiple recognition sites which densely decorate the BioMOF channels: (i) the thioether groups, deriving from the S-methyl-l-cysteine and (S)-methionine amino acid residues, able to recognize and capture Pb2+ and Hg2+ ions and (ii) the oxygen atoms of the oxamate moieties, which preferentially interact with Cd2+ ions, as revealed by single crystal X-ray diffraction. The flexibility of the pore environments allows these sites to work synergically for the simultaneous capture of different metal ions. The stability of the membranes for a potential regeneration process, a key-factor for the effective feasibility of the process in real life applications, was also evaluated and confirmed less than 1% capacity loss in each cycle.

Shaping Phenolic Resin-Coated ZIF-67 to Millimeter-Scale Co/N Carbon Beads for Efficient Peroxymonosulfate Activation.

Catalytic performance decline is a general issue when shaping fine powder into macroscale catalysts (e.g., beads, fiber, pellets). To address this challenge, a phenolic resin-assisted strategy was proposed to prepare porous Co/N carbon beads (ZACBs) at millimeter scale via the phase inversion method followed by confined pyrolysis. Specially, p-aminophenol-formaldehyde (AF) resin-coated zeolitic imidazolate framework (ZIF-67) nanoparticles were introduced to polyacrylonitrile (PAN) solution before pyrolysis. The thermosetting of the coated AF improved the interface compatibility between the ZIF-67 and PAN matrix, inhibiting the shrinkage of ZIF-67 particles, thus significantly improving the void structure of ZIF-67 and the dispersion of active species. The obtained ZACBs exhibited a 99.9% removal rate of tetracycline (TC) within 120 min, with a rate constant of 0.069 min-1 (2.3 times of ZIF-67/PAN carbon beads). The quenching experiments and electron paramagnetic resonance (EPR) tests showed that radicals dominated the reaction. This work provides new insight into the fabrication of high-performance MOF catalysts with outstanding recycling properties, which may promote the use of MOF powder in more practical applications.

Full‐Color and High‐Resolution Femtosecond Laser Patterning of Perovskite Quantum Dots in Polyacrylonitrile Matrix

AbstractLaser patterning of perovskite quantum dots (PQDs) in polymer matrix enables in situ synthesis, easy integration, and much improved long‐term stability, holding great promises for varieties of photonics, and optoelectronics applications. Although multi‐color PQD patterns have been demonstrated through tuning the halide stoichiometry, it remains significantly challenging to achieve full‐color patterns due to the slow and spontaneous crystallization of the chlorinated perovskite precursor at room temperature. Herein, polyacrylonitrile (PAN) is introduced to serve as the matrix material, the excess cyano groups of which would coordinate with dissociative cesium and lead cations in the precursor film, leading to the suppression of the unprompted crystallization process. Taking advantage of the nonthermal and contactless ultrafast femtosecond laser, full‐color PQDs are in situ fabricated by tuning the halide stoichiometry in the PAN matrix, with the emission wavelength in the range of 425–685 nm, spanning from deep blue to deep red color, and a sub‐diffraction feature size of ≈400 nm. The approach allows ultrafine and programmable fabrication of full‐color PQD arrays and arbitrary patterns with high resolution and stability. This facile, efficient, and reliable technique believed to offer a novel pathway for precise manufacturing of various photonic or optoelectronic devices based on patterned PQDs.

High performance multifunctional piezoelectric PAN/UiO-66-NO2/MXene composite nanofibers for flexible touch sensor

In this study, a flexible piezoelectric sensor based on polyacrylonitrile (PAN), zirconium-based MOF (UiO-66) with nitro (NO2) and two-dimensional material MXene composite nanofiber film was proposed. When pressure was applied, the three-dimensional structural nanopores were compressed, increasing the intercalation structure between the MXene nanosheets coated in the fibers. The double-packed system produced a higher resistance change under the same pressure load, which can be explained by the fact that the low-conductivity octahedral UiO-66-NO2 particles acted as a similar “buffer” between the highly conductive MXene. At the same time, a large number of hydrogen bonds between the surfaces of the two fillers enhanced the synergistic effect and promoted the interfacial coupling effect, so that more 31-helical conformation in the PAN matrix was converted into a planar zigzag conformation. This improved the piezoelectric performance and enabled the sensor to have a voltage output of about 200 V in the detection range. And because the polyhedral form of UiO-66-NO2 particles provided a rougher surface structure, the piezoelectric sensor can achieve a high sensitivity of 5.62 V/N. The other results showed that the dielectric constant of the designed flexible piezoelectric sensor was increased to 2.67, the dielectric loss was kept at a low level of 0.026, and the maximum elongation was 56.03 %. This multi-functional sensor shows great potential in the fields of health and medical treatment, human-computer interaction, etc.

A Novel Method to Enhance the Mechanical Properties of Polyacrylonitrile Nanofiber Mats: An Experimental and Numerical Investigation.

This study addresses the challenge of enhancing the transverse mechanical properties of oriented polyacrylonitrile (PAN) nanofibers, which are known for their excellent longitudinal tensile strength, without significantly compromising their inherent porosity, which is essential for effective filtration. This study explores the effects of doping PAN nanofiber composites with varying concentrations of polyvinyl alcohol (PVA) (0.5%, 1%, and 2%), introduced into the PAN matrix via a dip-coating method. This approach ensured a random distribution of PVA within the nanofiber mat, aiming to leverage the synergistic interactions between PAN fibers and PVA to improve the composite's overall performance. This synergy is primarily manifested in the structural and functional augmentation of the PAN nanofiber mats through localized PVA agglomerations, thin films between fibers, and coatings on the fibers themselves. Comprehensive evaluation techniques were employed, including scanning electron microscopy (SEM) for morphological insights; transverse and longitudinal mechanical testing; a thermogravimetric analysis (TGA) for thermal stability; and differential scanning calorimetry (DSC) for thermal behavior analyses. Additionally, a finite element method (FEM) analysis was conducted on a numerical simulation of the composite. Using our novel method, the results demonstrated that a minimal concentration of the PVA solution effectively preserved the porosity of the PAN matrix while significantly enhancing its mechanical strength. Moreover, the numerical simulations showed strong agreement with the experimental results, validating the effectiveness of PVA doping in enhancing the mechanical properties of PAN nanofiber mats without sacrificing their functional porosity.

Ultrasonication-induced re-dispersion of freeze-dried cellulose nanoparticles for improving strength and durability of PAN polymer matrix

Cellulose nanocrystals (CNCs) have acquired considerable attention owing to their noteworthy properties, including high crystallinity, biodegradability, high specific surface area, and excellent mechanical characteristics that alter the inherent features of the polymer matrix upon reinforcement. Typically, CNCs undergo freeze-drying or spray-drying to facilitate handling and dispersion in a hydrophobic polymer medium. Unfortunately, these drying procedures compromise the intrinsic nano-scale properties of CNCs. Therefore, achieving a uniform re-dispersion of dried CNCs is imperative to attain the desired characteristics in the polymer composite. This study specifically focuses on achieving a homogeneous re-dispersion of freeze-dried CNCs within a waste polyacrylonitrile (PAN) matrix through a simple ultrasonication treatment. The enhanced mechanical properties of the PAN polymer matrix validate the impact of ultrasound energy on re-dispersing CNCs. A noticeable improvement in the tensile properties of the composite polymer film is observed when CNC particles are well-dispersed in the PAN matrix. This observation is substantiated through SEM imaging, XRD, and FTIR data of both neat PAN and PAN–CNC composite films. The results affirm that particle dispersion plays a crucial role in augmenting the tensile properties of PAN composite films.

Zr-UiO-66, ionic liquid (HMIM+TFSI−), and electrospun nanofibers (polyacrylonitrile): All in one as a piezo-photocatalyst for degradation of organic dye

The synergistic effect provided by combining piezocatalysis and photocatalysis can assure the future of water cleaning. The Zr-UiO-66 (ZrU) piezo-photocatalyst was first synthesized through the solvothermal process and then followed by the incorporation with the liquid-based piezocatalyst of HMIM+TFSI− at three different concentrations to provide ZrU@ILs, which were subsequently incorporated into the piezocatalytic matrix of polyacrylonitrile (PAN). The solution of ZrU@IL/PAN was then subjected to electrospinning to fabricate the ZrU@IL/PAN nanofibers (NFs). Among the three dye models, Rhodamine B (RhB) was more degraded and the order of ZrU@IL/PAN NFs > ZrU/PAN NFs > ZrU@IL > IL/PAN NFs > pure PAN NFs > ZrU > HMIM+TFSI− was observed for its degradation in exposure to both ultrasonic (US) vibration and light radiation, approving the boosted influence of the three catalytic components of ZrU, HMIM+TFSI−, and PAN NFs in the degradation of RhB and more effectiveness of the fibrous form of catalysts compared to their corresponding catalytic powders. A synergistic effect was detected in the piezo-photodegradation efficiencies of RhB (2.2 %-95.4 %) compared to the individual photodegradation (0.0 %-21.3 %) and individual piezodegradation efficiencies (2.3 %-84.2 %). The ZrU@IL-1/PAN NFs as the optimal piezo-photocatalyst displayed high recycling after four cycles of usage, RhB mineralization percentage of 67 % within 40 min, and a pseudo-first-order kinetic rate constant being 1.67 and 12.8 times higher than that of individual piezocatalysis and individual photocatalysis. Tauc plots and Mott-Schottky measurements in agreement with the radical trapping experiments suggested the main role of O2•- and HO• species in the RhB degradation mechanism. LC-MS-MS was applied to clarify the intermediates generated during the RhB piezo-photodegradation process.

A novel phosphorus/nitrogen-containing polyacrylonitrile fiber with excellent flame retardancy and mechanical properties

To improve the flame retardancy, smoke suppression and mechanical properties of polyacrylonitrile (PAN) fiber, it was first modified with diethylenetriamine to prepare the aminated PAN fiber (A-PAN). Second, diethyl phosphite (DEP) was grafted onto the A-PAN to fabricate flame retardant PAN fiber (DEP-A-PAN). XPS and FTIR analysis confirmed that phosphorus and nitrogen elements were covalently bonded to the surface of PAN fiber. TGA revealed that the incorporation of DEP promoted char formation of PAN matrix and suppressed the thermal degradation. DEP-A-PAN exhibited a significantly reduced peak heat release rate (pHRR) compared to the control sample. Moreover, the limiting oxygen index (LOI) of DEP-A-PAN was up to 34.3 %, and remained at 26.6 % even after 50 laundering cycles (LCs), demonstrating excellent durable flame retardancy. Interestingly, DEP-A-PAN exhibited improved tensile strength of 2.97 cN/dtex. This work developed a simple and feasible method for preparing mechanical-enhanced flame retardant and smoke suppressive PAN fiber, which could be large-scale preparation.

Electrospinning-assisted porous skeleton electrolytes for semi-solid Li-O2 batteries.

Solid-state lithium-oxygen batteries offer great promise in meeting the practical demand for high-energy-density and safe energy storage. We have developed fibrous gel polymer electrolytes (GPEs) using a polyacrylonitrile (PAN) matrix via electrospinning. The 3D structure of GPEs enhances electrolyte absorption, while the interconnected design promotes strong interactions between Li+ and polar groups within the PAN matrix, thereby improving ion transport efficiency. In practical tests, both lithium symmetric cells and Li-O2 batteries demonstrated the ability to operate at high current densities over long cycles.

Thermomechanical properties of confined magnetic nanoparticles in electrospun polyacrylonitrile nanofiber matrix exposed to a magnetic environment: structure, morphology, and stabilization (cyclization).

Electrospun metal oxide-polymer nanofiber composites hold promise for revolutionizing biomedical applications due to their unique combination of electronic and material properties and tailorable functionalities. An investigation into the incorporation of Fe-based nanofillers for optimizing the polyacrylonitrile matrix was conducted, where the systematic and organized arrangement of inorganic components was achieved through non-covalent bonding. These carefully dispersed nanomaterials exhibit the intrinsic electronic characteristics of the polymers and concurrently respond to external magnetic fields. Electrospinning was utilized to fabricate polyacrylonitrile nanofibers blended with Fe2O3 and MnZn ferrite nanoparticles, which were thermomechanically, morphologically, and spectroscopically characterized in detail. With the application of an external magnetic field in the course of dynamic mechanical measurements under tension, the storage modulus of the glass transition T g of PAN/Fe2O3 rises at the expense of the loss modulus, and a new peak emerges at ∼350 K. For the PAN/MnZn ferrite nanofibers a relatively larger shift in T g (from ∼367 K to ∼377 K) is observed, emphasizing that in comparison to Fe2O3, Mn2+ ions in particular enhance the material's magnetic response in MnZn Ferrite. The magnetic oxide particles are homogenously dispersed in polyacrylonitrile, corroborated by high-resolution scanning electron microscopy. Both nanopowder additions lead to a slight shift of the peak towards larger angles, related to the shrinkage of the polymer. Produced nanofibers with high mechanical and heating efficiency can optimize the influence of the intracellular environment, magnetic refrigeration systems and sensors/actuators by their magnetic behavior and heat generation.

Modeling the Active Fragment of a Catalyst in a Polyacrylonitrile Matrix

Modeling the Active Fragment of a Catalyst in a Polyacrylonitrile Matrix

Synergetic effect of MXene/MoS2 heterostructure and gradient multilayer for highly sensitive flexible piezoelectric sensor

In this study, we proposed a flexible piezoelectric sensor made of gradient multilayer polyacrylonitrile (PAN) MXene/Molybdenum disulfide (MoS2) nanocomposites prepared by layer-by-layer electrospinning technology. Each layer of the composite film was formed by adding different mass ratios of MXene and MoS2 (MXene: MoS2 = 4:1, 2:1, 1:1) as filler materials, with a constant content of MXene (2% of the PAN matrix), and the concentration of MoS2 increases progressively from the inner layer to the outer layer. In addition, a heterojunction structure was formed using MXene and MoS2, which formed hydrogen bonds with –CN on PAN, thereby enhancing their interaction. By employing this novel concept of gradient multilayer and 2D/2D heterostructure, the interface coupling effect could be effectively promoted, and more 31−helical conformations could be transformed into planar zigzag conformations, significantly improving the dielectric, ferroelectric, and piezoelectric properties of the multilayer composite fiber films, thereby enhancing its output performance. With the gradient multilayer structure, the piezoelectric sensor exhibited excellent voltage sensitivity (14.9 V/N). The piezoelectric sensor detected body movement during basketball shooting and offered excellent breathability for enhanced comfort. It shows promise for use in health monitoring, electronic skin, and human-computer interaction.

Improving the electrochemical and physical properties of nickel cobaltite /polyacrylonitrile nanocomposites for supercapacitor applications

Nanocomposite films composed of polyacrylonitrile (PAN) doped with nickel cobaltite (NCO) nanoparticles (NPs) with different weight ratios have been prepared and characterized. Field emission scanning electron microscopy (FE-SEM) confirmed that the NCO NPs were successfully incorporated into the PAN matrix. The x-ray diffraction (XRD) studies showed that the PAN degree of crystallinity was lowered by the incorporation of NCO NPs in the polymer matrix. Other various characterization techniques including energy dispersive x-ray (EDX), Fourier transform infrared (FTIR), and thermal analysis were used. In addition, the effect of NCO NPs on the dielectric permittivity and ac-conductivity exhibits that the ac conductivity of PAN is enhanced from 0.06 ×10− 4 to 3.19 ×10− 4 S m−1 by doping with 10 wt% NCO NPs at room temperature (RT) and 1.0 MHz. Moreover, the optical properties showed that the NCO/PAN nanocomposites revealed lower transmittance and narrowed the optical bandgap (E g) of the PAN from 3.92 to 3.37 eV. Cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests were performed to investigate the electrochemical behavior of the studied nanocomposites. It was found that PAN loaded with 10 wt% NCO NPS attains an excellent specific capacitance of 1241 F g−1 at a current density of 0.5 A/g. Also, the cycling stability is significantly enhanced, and the capacitance retention rate approaches 93.2% after 5000 cycles, which provides the possibility of using the studied nanocomposite films for supercapacitor applications.

Use of hybrid polyacrylonitrile/polypyrrole/polyaniline nonwoven mats for removal of the Remazol Black B dye

We report the preparation of polyacrylonitrile/polypyrrole/polyaniline (PAN/PPy/PANI) mats, a new type of composite membrane obtained through an in situ chemical polymerization of pyrrole and aniline on an electrospun polymeric matrix of polyacrylonitrile, and their use for the capture and removal of Remazol Black B (RBB) dye molecules dissolved in an aqueous media. We characterized these membranes through scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), thermogravimetric analysis (TGA), and contact angle measurements. We observed that the coating of electrospun PAN fibers was uniform, with the resulting membrane exhibiting a hydrophilic character. When exposed to RBB aqueous solutions at room temperature, the PAN/PPy/PANI mats presented the highest adsorption capacity (247.7 mg g−1) at pH 2. While the kinetics and adsorption isotherm data were best described by pseudo-second-order (PSO) and Langmuir models, respectively, the RBB adsorption was favored by an increase in the temperature. After subjecting the RBB-loaded membrane to different elution procedures, we were able to achieve full desorption in just 10 min. The thermal and environmental stability of the composite membranes allowed us to use them in at least 6 consecutive adsorption/desorption cycles without noticeable loss of their properties. These results suggest that PAN/PPy/PANI membranes are promising adsorbent materials for use in water remediation protocols.

Muscovite as an inert filler for highly conductive and durable gel polymer electrolyte in sodium-ion batteries

Sodium-ion batteries emerge as complementary to commercially established lithium-ion batteries. The keynote of the presented study is sodium gel polymer electrolyte for efficient and safer post-lithium batteries. The study aims at better mechanical strength, higher ionic conductivity, and improved thermal properties of the gel polymer electrolyte. These properties strongly depend on the composition of the electrolyte. Ionic liquid and sulfolane as plasticizers improved the ionic conductivity of the electrolyte up to 5.5 mS cm−1. Polyacrylonitrile matrix established flexibility and mechanical strength up to 5.9 MPa. However, the most significant change is the partial substitution of polymer with an inert filler. For the first time, the inert filler in sodium gel polymer electrolyte is muscovite, which affects most of the properties of the polymer electrolytes. It broadens the anodic region of the electrochemical window even by 200 mV and reduces the dimensional shrinkage of the electrolyte by 1–4% compared to the reference sample. Furthermore, muscovite enhances the tensile strength of the electrolyte, delays thermal degradation, and improves the long-term stability of the GPE/Na interface. It also assures that the gel electrolyte is compatible with a hard carbon anode in a cell that delivers a capacity of 200 mAh g−1 at C/20.

An ion-released MgI2-doped separator inducing a LiI-containing solid electrolyte interphase for dendrite-free Li metal anodes

Lithium metal batteries are among the strong contenders to satisfy the ever-increasing needs of energy storage systems, which however suffer from poor composition of the solid electrolyte interphase (SEI) layer and uncontrolled Li dendrites formation. In this regard, we report on the design of an ion-released MgI2-doped polyacrylonitrile (PAN) based nanofiber (MPANF) separator, which can lead to conducive SEI layer and dendrite-free Li anode. The combination of the lithophilic MgI2 nanoparticles with polarized PAN matrix comprehensively functions as a high-compatible interpenetrating network to homogenize ionic transportation and confront dendrite growth. The released I ions introduce the high-ion-conductivity LiI into SEI layer, which could induce the formation of favorable and protective interface layer in the early stage, as embodied in the enrichment of advantageous components such as LiNxOy, Li2O, LiF, and Li3N. Profited from the high-affinity MPANF separator, the Li||Li symmetric cell achieves an ultra-low voltage hysteresis of 46 mV with an extended lifespan of 580 h. And a prolonged lifetime of 590 cycles with an enhanced specific capacity of 140.1 mAh g−1 and the Coulombic efficiency of 96.2% at 1 C can be obtained in full cells. This work may offer a facile and high-affinity alternative to traditional polymeric separators for high-performance and dendrite-free Li metal batteries.

Facile Uniaxial Electrospinning Strategy To Embed CsPbBr3 Nanocrystals with Enhanced Water/Thermal Stabilities for Reversible Fluorescence Switches.

All-inorganic halide perovskite nanocrystals with their fascinating optical properties have drawn increasing attention as promising nanoemitters. However, due to the intrinsic poor colloidal stability against the external environment, the practical applications are greatly limited. Herein, a facile and effective strategy for the in situ encapsulation of CsPbBr3 NCs into highly dense multichannel polyacrylonitrile (PAN) nanofibers via a uniaxial electrospinning strategy is presented. Such a facile uniaxial electrospinning strategy enables the in situ formation of CsPbBr3 NCs in PAN nanofibers without the introduction of stabilizers. Significantly, the obtained CsPbBr3 nanofibers not only display intense fluorescence with a high quantum yield (≈48%) but also present high stability when exposed to water and air owing to the peripheral protecting matrix of PAN. After immersing CsPbBr3@PAN nanofiber films in water for 100 days, the quantum yield of CsPbBr3@PAN nanofibers maintained 87.5% of the original value, which was much higher than that using CsPbBr3 NCs. Furthermore, based on the spectral overlap between the electrochromic material of ruthenium purple and fluorescence of CsPbBr3@PAN nanofiber films with excellent water stability, a reversible fluorescence switch is constructed with good fatigue resistance, suggesting their promising applications.

Regulating lithium-ion flow by piezoelectric effect of the poled-BaTiO3 film for dendrite-free lithium metal anode

Dendritic growth is regarded as the intrinsic cause of failure for the lithium metal rechargeable batteries, which blame on the uneven lithium-ion flux induced by the fragile native solid electrolyte interface (SEI) film. Herein, a functional SEI film is composed of BaTiO3 (BTO) dipole in polyacrylonitrile (PAN) matrix, to regulate lithium-ion flux through piezoelectric effect. It is found that, piezoelectric effect of the poled BTO film will induce a reversed local electric field on the dendrites bulge, thus reducing the aggregation of lithium-ion flow and slowing down dendrite growth. Moreover, the PAN matrix of the BTO film exhibited outstanding mechanical property of toughness and long fatigue lifespan, buffering volume change of lithium metal electrode during the plating/striping process. Under the effect of the poled BTO film, the lithium electrode achieved a flatter and smoother surface than that of native SEI film even after depositing a large area capacity of 10 mA h cm−2. Consequently, The Li||Poled-BTO-Cu half-cell delivered 94% coulombic efficiency over 180 cycles. Furthermore, the Poled-BTO-Li||FeLiPO4 could maintain the capacity at 110 mA h g−1 after 350 cycles.

Molecular Bridging Enables Isolated Iron Atoms on Stereoassembled Carbon Framework To Boost Oxygen Reduction for Zinc-Air Batteries.

Realizing the synergy between active site regulation and rational structural engineering is essential in the electrocatalysis community but still challenging. Here, a matrix-confined co-pyrolysis strategy based on molecular bridging is demonstrated to realize highly dispersed Fe atoms on stereoassembled carbon framework. Both polyacrylonitrile matrix and organic linker from metal-organic frameworks (MOFs) provide sufficient N-anchoring sites for the generation of Fe-N4 moieties. A high Fe loading of 2.9 wt.% is readily achieved based on the scalable approach without post-treatment. Owing to the presence of highly exposed Fe-N-C sites and well-tuned pore structures, isolated Fe atoms on porous carbon nanofiber framework (Fe-SA/NCF) exhibits decent oxygen reduction activity and stability in alkaline conditions via a near four-electron path, demonstrating superior performance as air cathode for zinc-air batteries (ZABs) to commercial Pt/C catalyst.