Ceramic Nanofibers Research Articles

(Invited) Engineering Interfaces in Solid-State Polymer-Ceramic Composite Electrolytes of Li-Ion Batteries

This talk presents our effort to engineer interfaces in solid-state polymer-ceramic composite electrolytes of lithium-ion batteries. A Grafting agent has been utilized to strengthen the polymer-ceramic interface. Also, a Li-ion conducting buffer layer has been employed to enhance interaction between the ceramic nanofibers and the polymer matrix. In addition, dopants and oxygen vacancies in ceramics can enhance interfacial interaction.

Super-insulating, ultralight and high-strength mullite-based nanofiber composite aerogels

Ceramic nanofiber aerogel is one of the most attractive insulation materials in recent years. However, its practical application ability is limited at high temperature due to high radiation heat transfer. Herein, we constructed a novel closed-cell/nanowire structured mullite-based nanofiber composite aerogel via electrospinning technology and solvothermal synthesis method. Hollow TiO2 spheres were used as pore-making material and infrared opacifier to reduce fiber solid heat conduction and high temperature radiation heat transfer simultaneously. In addition, TiO2 nanowires grown in-situ on the fiber surface further decrease the radiation heat transfer of aerogel and improve the mechanical properties. The unique structure endows the aerogel with high mechanical robustness (0.32–0.35 MPa, 10% strain), low density (39.2–47.5 mg/cm3) and ultralow thermal conductivity (~0.017 W m−1 K−1 at 25 ℃ and ~0.056 W m−1 K−1 at 1000 ℃). This work offers a novel strategy for the development of ceramic nanofiber aerogel at high temperature.

Strong Flexible Ceramic Nanofiber Membranes for Ultrafast Separation of Oil Pollutants

Strong Flexible Ceramic Nanofiber Membranes for Ultrafast Separation of Oil Pollutants

Ceramic Nanofiber Materials for Wound Healing and Bone Regeneration: A Brief Review.

Ceramic nanofibers have been shown to be a new horizon of research in the biomedical area, due to their differentiated morphology, nanoroughness, nanotopography, wettability, bioactivity, and chemical functionalization properties. Therefore, considering the impact caused by the use of these nanofibers, and the fact that there are still limited data available in the literature addressing the ceramic nanofiber application in regenerative medicine, this review article aims to gather the state-of-the-art research concerning these materials, for potential use as a biomaterial for wound healing and bone regeneration, and to analyze their characteristics when considering their application.

Ceramic nanofiber membrane anchoring nanosized Mn2O3 catalytic ozonation of sulfamethoxazole in water

Catalytic ceramic nanofiber membranes (Mn@CNMs) were prepared by anchoring Mn2O3 nanoparticles on the pits of attapulgite (APT) nanofibers via an impregnation and in-situ precipitation method. An integrated catalytic ozonation/membrane filtration process applying Mn@CNM was employed to degrade sulfamethoxazole (SMX) and the removal achieved up to 81.3% during a 7-h continuous filtration. The reactive oxygen species (ROS) quenching and radical detection experiments were conducted to determine the contribution of 1O2, ·OH and O2·- towards the catalytic degradation of SMX. Moreover, Mn@CNM exhibited wide applicability for real water matrix and the total removal of various kinds of emerging contaminants in real hospital wastewater reached up to 98.5%. The excellent performances of Mn@CNM were attributed to the nano-confinement effect in the membrane layer. First, anchoring Mn2O3 nanoparticles on the pits of the APT surface suppressed the growth and aggregation of nanosized Mn2O3, providing abundant reactive sites for catalytic ozonation. Second, the interlaced APT nanofibers formed nano-sized network structures, where ROS and SMX were confined in close vicinity and ROS have more chances to attack SMX. This work provides a promising strategy for the preparation of catalytic ceramic membrane with high catalytic efficiency for degradation of emerging contaminants in water.

Improved Energy Density and Energy Efficiency of Poly(vinylidene difluoride) Nanocomposite Dielectrics Using 0.93Na0.5Bi0.5TiO3-0.07BaTiO3 Nanofibers.

In modern electronic and power systems, it is essential to develop advanced dielectric materials with high energy density. One-dimensional ferroelectric ceramic nanofibers were proved to be a feasible strategy for improving the permittivity and energy density of nanocomposites. In this paper, to overcome the high loss issue of Na0.5Bi0.5TiO3 (NBT), a kind of novel nanofibers 0.93Na0.5Bi0.5TiO3-0.07BaTiO3 (NBT-BT) with large aspect ratio are synthesized by the electrospinning method and used as the dielectric fillers in trilayer structured poly(vinylidene difluoride) (PVDF) nanocomposites for energy storage applications. The finite element analysis is performed to evaluate the electric field distribution in the nanocomposites. The results showed that the trilayer structured nanocomposite loaded with 6 wt % NBT-BT nanofibers in the middle layer achieved the highest discharge energy density of 19.21 J cm-3 at 527 kV mm-1, which is 87.2% higher than that of pure PVDF (10.26 J cm-3 at 420 kV mm-1). Owing to the contribution of the barrier effect and interface polarization between adjacent layers, the energy density of the trilayer structured nanocomposites is significantly higher than that of the single-layer nanocomposites. This work provides a kind of novel one-dimensional ceramic fillers for obviously improving the energy density of polymer-based dielectrics.

Hierarchically porous Al2TiO5 ceramics via freeze-gel casting

Porous Al2TiO5 ceramics have drawn increasing attention in diverse applications owing to their low thermal expansion coefficient, and good resistance to thermal shock; however, Al2TiO5 ceramics prepared in previous studies still exhibited a relatively high density, which limited their further application in the field of high-temperature thermal insulation. Herein, we reported the successful fabrication of hierarchically porous Al2TiO5 ceramics with a unique three-dimensional skeleton structure formed by overlapped ceramic nanofibers. Results show that the introduction of SiO2 into Al2TiO5 nanofibers could significantly improve their thermal stability and meanwhile reduce their formation temperature. Al2TiO5 nanofibers with 10 mol% SiO2 exhibited a superior microstructure and excellent thermal stability, and were selected as the raw material in the subsequent preparation of corresponding porous ceramics. Porous Al2TiO5 ceramics prepared by the freeze-gel casting exhibited a unique hierarchical pore structure with large pores originating from the sublimation of ice crystal and small pores formed by the overlapped of fibers. This unique microstructure endowed porous ceramics with an ultra-high porosity (97.59–95.59%), ultra-low thermal conductivity (0.0456–0.0754 W m−1 K−1) and excellent thermal stability. Owing to these outstanding characteristics, the resulting porous Al2TiO5 ceramics are expected to be employed as the high-temperature thermal insulation material in a wide spectrum of advanced applications.

Multiphase ceramic nanofibers with super-elasticity from − 196–1600 ℃

Ceramics, as an excellent functional-structural material, serve widely in all areas of humanity production and life. However, the intrinsic brittleness of ceramic makes it a great challenge to design a reliable structure that can resist the mechanical stresses and sharp thermal shocks under extreme conditions. Here, we designed and delivered multiphase ceramic nanofibers (MPC-NFs) with robust structural and thermal stabilities. The superiority of the structural design is that the mutual inhibition of the two crystalline phases with continuous energy input, and the synergetic effect of the crystalline-amorphous phase endows multidimensional flexibility of ceramics in a high-temperature environment. The MPC-NFs possess superior structural stability from deep-cryogenic (−196 °C) along the way to ultra-high temperature (1600 °C) and structural strength that can resist thousand large-scale buckling or compressive cycles. This work not only developed a reliable material for thermal insulation in extreme environments, but also provides new theoretical insight on the elasticity in ceramics.

Solid-state lithium battery with garnet Li7La3Zr2O12 nanofibers composite polymer electrolytes

In recent years, solid-state lithium-ion batteries with high safety and excellent performance have become a research hotspot. Garnet Li7La3Zr2O12 (LLZO) has been widely used in lithium-ion batteries because of its high ionic conductivity, wide electrochemical window, excellent thermal performance, and promising stability. In this study, Ga-LLZO was prepared by the electrospinning method and combined with PVDF-HFP to prepare a composite polymer electrolyte. The addition of 15 wt% Ga-LLZO nanofibers in the electrolyte improved the ionic conductivity, reaching 8.92 × 10−4 S·cm−1 at room temperature. The electrochemical window for PVDF-HFP/LiTFSI/Ga-LLZO composite polymer electrolyte was 5.2 V vs Li/Li+. In addition, LiFePO4|PVDF-HFP/LiTFSI/Ga-LLZO|Li exhibited good cycling performance and rate capability. High-performance composite electrolyte films of ceramic nanofiber Ga-LLZO and polymer were successfully prepared for high-performance solid-state lithium batteries.

Low temperature synthesis of high-entropy (Y0.2Yb0.2Sm0.2Eu0.2Er0.2)2O3 nanofibers by a novel electrospinning method

High-entropy ceramics (HECs) show outstanding properties such as amorphous-like thermal conductivities, colossal dielectric constant, superionic conductivity, enhanced electromagnetic wave absorption ability, super hardness and strength, which are promising for structural and functional applications. However, the high synthesis temperature has become the bottleneck that hinders the scale-up production and practical applications of HECs. It is thus appealing to develop a novel low-temperature process for the synthesis of HECs. To demonstrate the feasibility of low-temperature synthesis, herein, an electrospinning method has been utilized, for the first time, for the synthesis of high-entropy (Y0.2Yb0.2Sm0.2Eu0.2Er0.2)2O3 nanofibers. It has been found that after electrospinning from liquid precursors single phase (Y0.2Yb0.2Sm0.2Eu0.2Er0.2)2O3 solid solution with bixbyite structure can be formed by calcining at a temperature as low as 500 °C, which is at least about 1000 °C lower than that used in the solid-state synthesis method. The as-prepared (Y0.2Yb0.2Sm0.2Eu0.2Er0.2)2O3 nanofibers are continuous and uniform with a smooth surface and a small diameter of 150 nm. It is also intriguing that the average grain size of (Y0.2Yb0.2Sm0.2Eu0.2Er0.2)2O3 is only about 10 nm, which is much smaller than that in the solid-state synthesized powders. In addition, all the elements are homogeneously distributed along the nanofibers. This work demonstrates that high-entropy ceramic nanofibers can be synthesized from liquid precursors at low temperatures through a simple, efficient, and low-cost electrospinning method, which opens up a new avenue for the low-temperature synthesis of HECs.

Nanoparticle-embedded hydrogel synthesized electrodes for electrochemical oxidation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)

In this study, sliver (Ag) and gold (Au) nanoparticles (NPs) were embedded on poly (acrylic acid) (PAA)/poly (allylamine) hydrochloride (PAH) hydrogel fibers for improved electrochemical oxidation (EO) of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) removal. The NPs-loaded PAA/PAHs shows the better charge transport compared to the ceramic nanofiber membranes (CNM) electrodes. At 10 mA cm−2 of current density, the Ag-PAA/PAH electrodes showed a faster removal of PFAS compared to the Ag-CNM electrode probably due to large surface area-volume ratio and high porosity from the hydrogel. Among NPs-loaded PAA/PAH electrodes, the Ag/Au-PAA/PAH electrodes showed the highest removal of PFOA (72%) and PFOS (91%) in 2 h with the maximum removal rate of PFOA (0.0046 min−1) and PFOS (0.0093 min−1). The rapid PFOS removal is possibly due to the high activity of electron transfer with a higher redox potential of SO4•- than •OH. The highly stable F− generation was obtained from each electrode during reproducibility (n = 3). The net energy consumption from Ag/Au–PAA/PAH electrode was 164.9 kWh m−3 for 72% PFOA removal and 90 kWh m−3 for 91% PFOS removal, respectively. The developed Au-PAA/PAH electrodes were applied to lake water samples and showed acceptable PFOS removal (65%) with relative standard deviations (RSD) of 10.2% (n = 3) at 10 mA cm−2 of current density. Overall, the NP-embedded hydrogel nanofibers were proven to be a promising sustainable catalyst for the electrochemical PFAS oxidation in water.

Preparation of high entropy nitride ceramic nanofibers from liquid precursor for CO2 photocatalytic reduction

AbstractSubjected to the manufacturing methods (sputtering or mechanochemical synthesis), the reported high entropy nitrides (HENs) were limited to the forms of coating and powder. Here, we report a novel strategy in preparing HEN ceramic nanofibers (HENCNFs) from liquid precursor via electrospinning followed by high‐temperature NH3 atmosphere nitridation. The as‐prepared HENCNFs include five uniform dispersed metal elements, Ti, Hf, Nb, Ta, and Mo, and have a single face‐centered cubic structure. Interestingly, the obtained HENCNFs show photocatalyst activity in CO2 reduction. The product selectivity of photocatalytic CO2 reduction reaction is 96.4%, and no performance degradation was detected during five cycles photocatalysis test.

Silica ceramic nanofiber membrane with ultra-softness and high temperature insulation

Silica ceramic nanofiber membrane with ultra-softness and high temperature insulation

Characterization of novel high-entropy (La0.2Nd0.2Sm0.2Dy0.2Yb0.2)2Zr2O7 electrospun ceramic nanofibers

We present a simple way to fabricate high-entropy (La0.2Nd0.2Sm0.2Dy0.2Yb0.2)2Zr2O7 (HE-RE2Zr2O7) ceramic nanofibers using the electrospinning and annealing processing in this work. The microstructure of nanofibers was characterized by thermal gravity-differential scanning calorimetry (TG-DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the diameter and grain growth of HE-RE2Zr2O7 nanofibers under 1000 °C was analyzed. Results indicate that HE-RE2Zr2O7 nanofibers can be prepared at temperatures above 400 °C and the crystallite size can be controlled by annealing temperature. Both diameter and the grain growth of HE-RE2Zr2O7 nanofibers are lower than that of La2Zr2O7 nanofibers, attributed to the sluggish diffusion effect. The advantages of HE-RE2Zr2O7 nanofibers can further enlarge the application of nanofibers in the aspect of high-temperature thermal insulation materials.

Influence of surface functionalization of ceramic nanofibers on morphological, physical and mechanical properties of unsaturated polyester nanocomposites

Alumina nanofibers at 0.25wt%, 0.5wt%, 0.75wt%, and 1wt% concentration were used to modify unsaturated polyester resin. Additionally, vinyl silane treated alumina nanofibers were used at the same concentrations and were compared to pristine alumina nanofibers. The SEM images showed a variation in the surface morphology when alumina nanofibers and the BET measurement showed surface area increase from 111 m2/g to 122 m2/g when nanofibers were treated with silane agent. The dispersion of alumina nanofibers into the host unsaturated polyester resin was successfully achieved by three roll mill dispersion. The TEM images showed good dispersion of alumina nanofibers in polyester resin. Although pristine nanofibers showed greater agglomeration at 1wt% concentration, the effect of agglomeration was reduced in the 1wt% concentration. The weight loss measurements from TGA showed that the thermal stability of nanocomposites increased with addition of nanofibers and the lower onset degradation temperature can be tailored to improve by a maximum of 5.5% for silane treated nanofiber. Viscosity and contact angle which are key factors affecting the processability has seen to be positively altered by silane treatment. Additional tensile, flexural, and Izod impact properties were evaluated for the nine material systems and the properties were summarized.

Synthesizing Superior Flexible Oxide Perovskite Ceramic Nanofibers by Precisely Controlling Crystal Nucleation and Growth.

Oxide perovskite ceramics are cornerstone materials of electronic devices, but they easily break under bending. Such brittle failure phenomenon limits their applications in emerging flexible electronics. Here, the authors propose a scalable approach of sol-gel electrospinning to synthesize flexible perovskite Li0.35 La0.55 TiO3 (LLTO) nanofibers (NFs) by reducing grain sizes and pore defects in the NFs. The strategy is to precisely control crystal nucleation and growth by forming homogeneous nuclei in the sol before electrospinning and to construct soft twin and amorphous grain boundaries by controlling calcination temperatures. Ball-milling the sol promotes the formation of numerous LLTO nuclei and thus effectively refines grains, while using gradient calcination temperatures from 200 to 900°C creates intricate soft grain boundaries. The individual LLTO NF shows ceramic toughness with an elastic modulus of ≈40GPa and the NF film demonstrates silk-like softness with a large elastic strain of 1.51%. Moreover, the LLTO film shows superior fatigue resistance and it maintains structure well after repeated tensile-buckling cycles at 40% strain. The proposed strategy facilitates to develop flexible oxide perovskite ceramic films with appealing applications.

Electrochemical Behavior of Inductively Sintered Al/TiO2 Nanocomposites Reinforced by Electrospun Ceramic Nanofibers.

This study is focuses on the investigation of the effect of using TiO2 short nanofibers as a reinforcement of an Al matrix on the corrosion characteristics of the produced nanocomposites. The TiO2 ceramic nanofibers used were synthesized via electrospinning by sol-gel process, then calcinated at a high temperature to evaporate the residual polymers. The fabricated nanocomposites contain 0, 1, 3 and 5 wt.% of synthesized ceramic nanofibers (TiO2). Powder mixtures were mixed for 1 h via high-energy ball milling in a vacuum atmosphere before being inductively sintered through a high-frequency induction furnace at 560 °C for 6 min. The microstructure of the fabricated samples was studied by optical microscope and field emission scanning electron microscope (FESEM) before and after corrosion studies. Corrosion behavior of the sintered samples was evaluated by both electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PPT) in 3.5% NaCl solution for one hour and 24-h immersion times. The results show that even though the percentage of ceramic nanofibers added negatively control corrosion resistance, it is still possible to increase resistance against corrosion for the fabricated nanocomposite by more than 75% in the longer exposure time periods.

Production and qualification of an electrospun ceramic nanofiber material as a candidate future high power target

In an effort to develop and design next generation high power target materials for particle physics research, the possibility of fabricating nonwoven metallic or ceramic nanofibers by electrospinning process is explored. A low-cost electrospinning unit is set up for in-house production of various ceramic nanofibers. Yttria-stabilized zirconia nanofibers are successfully fabricated by electrospinning a mixture of zirconium carbonate with high-molecular weight polyvinylpyrrolidone polymer solution. Some of the inherent weaknesses of electrospinning process like thickness of nanofiber mat and slow production rate are overcome by modifying certain parts of electrospinning system and their arrangements to get thicker nanofiber mats of millimeter order at a faster rate. Continuous long nanofibers of about hundred nanometers in diameter are produced and subsequently heat treated to get rid of polymer and allow crystallize zirconia. Specimens were prepared to meet certain minimum physical properties such as thickness, structural integrity, thermal stability, and flexibility. An easy innovative technique based on atomic force microscopy was employed for evaluating mechanical properties of single nanofiber, which were found to be comparable to bulk zirconia. Nanofibers were tested for their high-temperature resistance using an electron beam. It showed resistance to radiation damage when irradiated with 1 MeV ${\mathrm{Kr}}^{2++}$ ion. Some zirconia nanofibers were also tested under high-intensity pulsed proton beam and maintained their structural integrity. This study shows for the first time that a ceramic nanofiber has been tested under different beams and irradiation condition to qualify their physical properties for practical use as accelerator targets. Advantages and challenges of such nanofibers as potential future targets over bulk material targets are discussed.

Polymer templates effects on microstructure and mechanical properties of electrospun mullite nanofibers

Polymer templates are important additives for electrospun ceramic nanofibers and have strong relationship to its properties. In this study, polyvinylpyrrolidone (PVP) and polyvinyl butyral (PVB) were used as templates to prepare mullite nanofibers. The morphology, microstructure and mechanical properties of the nanofibers were investigated and compared. Results show that after 1000 °C calcination, fibers prepared using PVB had a porous structure with surface area of 40.11 m2/g, and were composed of mullite crystals with elastic modulus of ∼27.5 GPa. However, the fibers prepared using PVP had a dense structure with surface area of 8.14 m2/g, and were composed of γ-Al2O3 and mullite crystals with a higher elastic modulus of ∼79.4 GPa. The influence mechanism was confirmed that the different binding states of polymer and aluminasilica precursor were the main reason for the fiber differences. These results give a reference for polymer template categories selection for preparing mullite nanofibers applied in different areas like filtration, catalysis and insulation.

One‐dimensional electrospun ceramic nanomaterials and their sensing applications

AbstractOne‐dimensional sensing materials that are prepared via electrospinning and controlled annealing exhibit intrinsic properties, such as electron transmissivity, magnetic susceptibility, specific heat capacity, as well as optical and mechanical characteristics. Particularly, the electronic transmission characteristics of the ceramic fiber materials, such as the electrical conductivity, photocurrent, magnetoresistance, nanocontact resistance, and dielectric properties, exhibited great potential for applications in the next generation of electronic sensing devices. First, electrospun ceramic materials with different structural and functional characteristics were reviewed here, after which the strategies for improving their properties, as well as the method for assembling the flexible devices, are summarized. Moreover, the electrospun ceramic nanofibers were detailedly discussed regarding applications in device construction and wearable electronics, such as photosensors, gas sensors, mechanical sensors, and other energy storage devices. Finally, the future development direction of the electrospinning technology for multifunctional and wearable electronics skin was proposed.