1D Nanofibers Research Articles

Nicotinamide-based supergelator self-assembling via asymmetric hydrogen bonding NH⋯OC and H⋯Br− pattern for reusable, moldable and self-healable nontoxic fuel gels

HypothesisDevelopment of highly efficient low-molecular weight gelators (LMWGs) for safe energy storage materials is of great demand. Energy storage materials as fuel gels are often achieved by construction of hybrid organic frameworks capable of multiple noncovalent interactions in self-assembly, which allow tuning required properties at the molecular level by altering individual building blocks of the LMWG. However, LMWGs have limited rechargeable capability due to their chemical instability. ExperimentsWe designed, synthesized and characterized a novel, bio-inspired chiral gemini amphiphile derivative 1 containing N-hexadecyl aliphatic tails from quaternized nicotinamide-based segment and bromide anion showing supergelation ability in water, alcohols, aprotic polar and aromatic solvents, with critical gel concentrations as low as 0.1 and 0.035 wt% in isopropanol and water, respectively. FindingsNanostructural architecture of the network depended on the solvent used and showed variations in size and shape of 1D nanofibers. Supergelation is attributed to a unique asymmetric NH⋯OC, H⋯Br− hydrogen bonding pattern between H-2 hydrogens from nicotinamide-based segment, amide functional groups from chiral trans-cyclohexane-1,2-diamide-based segment and bromide ions, supporting the intermolecular amide–amide interactions appearing across one strand of the self-assembly. Gels formed from 1 exhibit high stiffness, self-healing, moldable and colorable properties. In addition, isopropanol gels of 1 are attractive as reusable, shape-persistent non-toxic fuels maintaining the chemical structure with gelation efficiency for at least five consecutive burning cycles.

Fe3C/CoFe2O4 nanoparticles wrapped in one-dimensional MIL-53(Fe)-derived carbon nanofibers as efficient dual-function oxygen catalysts

Structure engineering for non-precious-metal catalyst plays the major roles in governing the activity and stability for oxygen evolution/reduction reactions (OER/ORR). Herein, via an electrospinning method, one-dimensional (1D) carbon fibers containing MIL-53 (Fe) and Co3+ are obtained as precursor for preparation of Fe3C/CoFe2O4-embedded carbon nanofibers (Fe3C/CoFe2O4@CNFs). Scanning electron microscopy image of Fe3C/CoFe2O4@CNFs-1.5 (mass ratio of MIL-53(Fe) to CoCl3·6H2O is 1.5) shows that it has a well-formed 1D structure with diameters of 200–300 nm. Hydrophilic surface with a contact angle of 16.5° is detected for Fe3C/CoFe2O4@CNFs-1.5 (250.1 m2 g−1), which shows a promising bifunctional activity with ΔE = 0.73 V (E1/2 = 0.84 V (ORR) and Ej10 = 1.57 V (OER)). For ORR, E1/2 of Fe3C/CoFe2O4@CNFs-1.5is close to that of commercial Pt/C (0.85 V),while its activity maintenance (92.5%) is much better than Pt/C (78.4%) after 30000 s, indicating that low-valence interfaces of CoFe2O4 (Co2+) and Fe3C (Fe2+) can provide multiple active sites to stabilize ORR rate. For OER, Fe3C/CoFe2O4@CNFs-1.5 has a low overpotential of 340 mV at 10 mA cm−2 and a high Faraday efficiency of 92.13%. Co2+ acts as an initiator to boost the formation of active CoOOH for OER. Oxygen vacancies on the reverse spinel structure of CoFe2O4 make the surface Co2+ easier to be oxidized to Co3+ (CoOOH). Fe3C/CoFe2O4 wrapped in carbon fiber lowers their aggregation and corrosion during ORR/OER. Networks constructed by the interconnected 1D nanofibers can provide 3D pathways for mass transfer. It indicates that bimetallic species (Fe/Co) can change the electronic and interface structures to promote bifunctional activity.

Enhancement of the Supercapacitive Performance of Cobalt-tin-cyanate Layered Structures through Conversion from 2D Materials to 1D Nanofibers

Rational design of the micro-nanomorphology is highly desired for metal hydroxides to achieve overall high-performance electrodes for supercapacitor and energy storage applications. Here, in the current study, we have succeeded in controlling the morphology of Sn/Co nanolayered structures to obtain plate and nanofibrous morphologies. Additionally, the plate nanostructures could be transformed to obtain plate-nanofibrous morphologies. In this trend, dual anions such as cyanate and nitrate are applied to intercalate among the nanolayers of cobalt-tin and act as building blocks or pillars, producing a series of nanolayered structures. By repulsion forces among the intercalated anions, the nanolayers of Sn/Co are curled and converted to nanofibers. This conversion was confirmed by scanning electron microscopy. In addition, the intercalation reactions and nanolayered structures were indicated by X-ray diffraction, thermal analyses and Fourier-transform infrared spectroscopy. The electrochemical supercapacitive behavior of the different nanostructures of Sn/Co HDS and Sn/Co LDH, such as plate, Plate-nanofiber and nanofibrous morphology has been investigated in three assembly electrode system. The results suggested that the nanofiber morphology of Sn/Co LDH exhibited better specific capacitance performance than the other two morphologies. The enhanced specific capacitance (658 Fg−1) and excellent cyclic stability (89%) of the nanofibers of the Sn/Co LDH could be attributed to the synergistic effects between the electric double layer capacitive character of the tin and the pseudocapacitance nature of the cobalt.

Polymer-Derived Electrospun Co3O4@C Porous Nanofiber Network for Flexible, High-Performance, and Stable Supercapacitors

1D nanofibers with higher surface area, small pore size, high porosity, good electrical conductivity, and relatively high production rate with high fiber interconnectivity have gained attention as ...

Porous nitrogen-enriched hollow carbon nanofibers as freestanding electrode for enhanced lithium storage

One-dimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices, especially for developing freestanding film electrodes. Here we develop a porous, nitrogen-enriched, freestanding hollow carbon nanofiber (PN-FHCF) electrode material via filtration of polypyrrole (PPy) hollow nanofibers formed by in situ self-degraded template-assisted strategy, followed by NH3-assisted carbonization. The PN-FHCF retains the freestanding film morphology that is composed of three-dimensional networks from the entanglement of 1D nanofiber and delivers 3.7-fold increase in specific surface area (592 m2·g−1) compared to the carbon without NH3 treatment (FHCF). In spite of the enhanced specific surface area, PN-FHCF still exhibits comparable high content of surface N functionalities (8.8%, atom fraction) to FHCF. Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity, high-rate property and good cycling stability when applied as self-supporting anode in lithium-ion batteries, superior to those of FHCF without NH3 treatment.

Electrospun Inorganic Nanofibers for Oxygen Electrocatalysis: Design, Fabrication, and Progress

AbstractElectrospinning has received tremendous attention in terms of the design and fabrication of 1D nanofibers for oxygen electrocatalysis in fuel cells and metal‐air batteries, owing to their high surface area, short charge transport path, superior chemical stability, etc. In this review, a brief introduction is given for fuel cells, metal‐air batteries, and the operation principle of electrospinning. After that, the recent progress of the noble‐metal‐free electrocatalysts prepared through electrospinning, mainly containing heteroatoms‐doped electrospun carbon nanofibers (ECNFs), ECNFs functionalized with transition metal nanoparticles and their compounds (alloy, oxides, carbides, nitrides, sulfides, phosphides), and unique nanostructured transition metal‐nitrogen‐ECNFs (including single‐atom catalysts) are summarized. In this section, electrospun electrodes with self‐standing peculiarity are emphasized. Next, other kinds of electrospun nanofibers based on oxides, nitrides, and carbides as electrocatalysts or their hybrid materials are also discussed. Finally, the prospects and possible future research direction of electrospun NFs‐based oxygen electrocatalysts are also presented. This comprehensive review is anticipated to be valuable and helpful in the context of understanding the design and fabrication of advanced energy conversion and storage devices.

A-site deficient perovskite nanofibers boost oxygen evolution reaction for zinc-air batteries

Among the various perovskites, Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) has been theoretically proved to have the prominent intrinsic oxygen evolution reaction (OER) catalytic activity in the alkaline solutions. Whereas, most of the measured bulk BSCF samples suffer the unsatisfactory OER activities which are much more inferior than that of the state-of-the-art catalyst of IrO2. In this work, we synthesize the A-site deficient BSCF nanofibers with the diameter of 300 nm by electrospinning for the first time. Thanks to the one dimensional (1D) nanofiber structure and A-site deficiency, the optimized BSCF nanofibers (BSCF-80-ES) demonstrate the remarkably enhanced OER activity with a low potential of 1.54 V at 10 mA cm−2 in 1 M KOH and an improved oxygen reduction reaction (ORR) activity. It is noteworthy that the OER potential of BSCF-80-ES keeps almost unchanged during the long-term test, indicating an excellent OER stability. Moreover, BSCF-80-ES with the high bifunctional catalytic activity and superb stability can be used as a promising oxygen catalyst for aqueous and flexible solid-state zinc-air batteries.

Constructing fibril-in-tube structures in ultrathin CeO2-based nanofibers as the ideal support for stabilizing Pt nanoparticles

The intriguing one-dimensional (1D) nanofibers with secondary structures (e.g., hollow, core-sheath, fiber-in-tube) have attracted much attention for their unique open structure, high surface area, and hierarchical pore structure. This work utilized single-spinneret electrospinning to construct mesoporous CeO2-based ultrathin nanofibers with a new fibril-in-tube morphology. The intriguing fibril-in-tube structure within Al2O3/CeO2 nanofibers was achieved by carefully selecting two different metal precursors with different decomposition rates upon calcination. The use of Al(acac)3 as Al2O3 precursor, which rapidly releases gaseous pieces and leads to the growth kinetics varied along the radial direction of nanofibers, is critical to the formation of fibril-in-tube structure. The new CeO2 nanofibers with different amount of Al2O3 endowed with homogenous elemental distribution and were explored as reliable metal supports toward stabilizing Pt nanoparticles under harsh aging. This inspiring result was ascribed to an energy barrier established by reducible (CeO2) and non-reducible oxide (Al2O3), strong metal-support interaction between Pt and CeO2, as well as the physical confinement caused by the fibril-in-tube structure. The resultant new catalytic system (referred to Pt@Al2O3/CeO2) displayed good sinter-resistant performance and exhibited 13-times great catalytic activity than that of Pt@Al2O3 catalyst after harsh aging at 700 °C toward the hydrogenation of p-nitrophenol.

Porous SnO2/C Nanofiber Anodes and LiFePO4/C Nanofiber Cathodes with a Wrinkle Structure for Stretchable Lithium Polymer Batteries with High Electrochemical Performance.

Stretchable lithium batteries have attracted considerable attention as components in future electronic devices, such as wearable devices, sensors, and body‐attachment healthcare devices. However, several challenges still exist in the bid to obtain excellent electrochemical properties for stretchable batteries. Here, a unique stretchable lithium full‐cell battery is designed using 1D nanofiber active materials, stretchable gel polymer electrolyte, and wrinkle structure electrodes. A SnO2/C nanofiber anode and a LiFePO4/C nanofiber cathode introduce meso‐ and micropores for lithium‐ion diffusion and electrolyte penetration. The stretchable full‐cell consists of an elastic poly(dimethylsiloxane) (PDMS) wrapping film, SnO2/C and LiFePO4/C nanofiber electrodes with a wrinkle structure fixed on the PDMS wrapping film by an adhesive polymer, and a gel polymer electrolyte. The specific capacity of the stretchable full‐battery is maintained at 128.3 mAh g−1 (capacity retention of 92%) even after a 30% strain, as compared with 136.8 mAh g−1 before strain. The energy densities are 458.8 Wh kg−1 in the released state and 423.4 Wh kg−1 in the stretched state (based on the electrode), respectively. The high capacity and stability in the stretched state demonstrate the potential of the stretchable battery to overcome its limitations.

Electrospun Highly Crystalline ZnO Nanofibers: Super‐Efficient and Stable Photocatalytic Hydrogen Production Activity

AbstractZnO has tremendous potential in photocatalysis, but only has moderate activity and poor stability because of the sluggish charge transfer and easy aggregation problem, respectively. In this work, ZnO photocatalyst with well‐defined one dimensional (1D) nanofiber structure was successfully fabricated for overcoming these defects. The results revealed that the ZnO nanofibers consist of compactly packed particles that form a cylinder type fiber in highly crystalline and high purity. The robust 1D nanostructure not only can suppress the aggregation of nanoparticles, but also facilitate the interparticle charge transfer. Besides, the mesoporous structure generated through the ZnO particle‐particle interconnection can promote the adsorption of reactants and desorption of products. Benefiting from these merits, the ZnO nanofibers photocatalyst presented superior higher and stable hydrogen production ability than that of nanoparticles counterpart. The photocatalytic hydrogen generation rate of the ZnO nanofibers was estimated to be 1031.8 μmol g−1 h−1, which was about 1.5 times higher than that of ZnO nanoparticles. Moreover, the ZnO nanofibers photocatalyst can maintain its 93.2 % H2‐production rate after five recycle experiments, whereas only 55.8 % for ZnO nanoparticles. This study provides an effective way to solve the energy problem by using solar energy.

Enhanced electrochemical properties of ZnO encapsulated in carbon nanofibers as anode material for lithium-ion batteries

The amorphous ZnO particles encapsulated in porous nitrogen-doped carbon nanofibers (ZnO@PN-CNFs) are synthesized by electrospinning process and heat treatment. The enhanced electrochemical properties of ZnO@PN-CNFs are based on the porous nanostructure, high length/diameter (L/D) ratio, doped nitrogen, and uniform distributed amorphous ZnO nanoparticles. The results show amorphous ZnO particles in carbon nanofibers avoid the pulverization and alleviated the volume expansion, as well as make the cycling of the anode quickly reach stable. Furthermore, the nitrogen-doped carbon improves electron conductivity while one-dimensional (1D) nanofibers with high L/D ratio own a short diffusion path and high electronic transportation efficiency along the longitudinal direction. Meanwhile, the porous nanostructure from urea pyrolysis produces thinner wall and further shortens the ionic transport distance. Therefore, high capacity and long-cycling life are achieved. And the ZnO@PN-CNF electrode shows a high discharge capacity (1073.2 mAh g−1 at 0.1 A−1) after 100 cycles. Moreover, the ZnO@PN-CNF electrode presents a high discharge capacity of 703.1 mAh g−1 even at 1 A−1 after 400 cycles. In this work, urea not only stops the ZnO from crystallization, leading to uniform distributed amorphous small ZnO particles, but also makes numerous pores in the carbon nanofibers, enlarging the touching area with electrolyte and shortening the transport distance to ZnO particles. It is a promising way by adding urea to alleviate volume expansion and pulverization of the crystal particles and then enhance the performance of electrode.

Highly efficient electrochemical energy storage of fluorinated nano-polyindoles with different morphology

The introduction of fluorine into a compound or material is known to impart a range of interesting functionalities; however, the poor electrochemical capacity of existing fluorinated polymers limits their application in the field of energy storage. Thus, we herein report the successful preparation of several fluorinated polyindole materials exhibiting high energy storage behaviours using a simple electropolymerization strategy. Scanning and transmission electron microscopic images reveal that the monofluorinated polyindoles are mainly composed of one-dimensional (1D) nanofibers and nanorods, whereas 1D nanowires and two-dimensional (2D) nanosheets are obtained for the difluorinated polyindoles. Interestingly, the prepared fluorinated polyindoles are found to exhibit the highest specific capacitances among all reported fluorinated materials (i.e., 261–528 F g−1 at 18 A g−1). In addition, they exhibit a good cycle stability as well as a high rate capability. Our results indicate that fluorinated nano-polyindoles can be considered as promising electrode materials for energy storage applications.

CdS/ZnS/ZnO ternary heterostructure nanofibers fabricated by electrospinning for excellent photocatalytic hydrogen evolution without co-catalyst

AbstractIn recent years, ternary heterostructures (HSs) composed of three semiconductors have attracted significant attention because of the effective separation and transfer of photogenerated electrons and holes in these materials. In this work, new ternary CdS/ZnS/ZnO (CZZ) HSs with one-dimensional (1D) nanofiber morphology have been successfully fabricated for the first time by a series of processes: electrospinning ZnO nanofibers, sulfurizing ZnO in situ to form ZnS/ZnO binary HSs, and depositing CdS quantum dots in situ on the ZnS/ZnO HSs. Benefiting from the efficient separation and transfer of photoinduced charge carriers, the optimized CZZ ternary HSs exhibit a hydrogen evolution rate of 51.45 mmol h−1 g−1 (quantum efficiency: 26.88% at 420 nm) without any co-catalyst, which is 93.54 and 2.28 times higher than those exhibited by pristine ZnO and ZnS/ZnO binary HSs, respectively, under the same conditions. Furthermore, the rate of hydrogen evolution over the 1D CZZ nanofibers is significantly higher than that over 2D CZZ nanosheets (27.25 mmol h−1 g−1, in the presence of a Pt co-catalyst) prepared by the same sulfurization and deposition procedures. This can be ascribed to the significantly smaller geometric sizes of 1D nanofibers compared to those of 2D nanosheets, resulting in effectively suppressed recombination of photogenerated charge carriers and promotion of photocatalytic H2 evolution performance.

RETRACTED: Tin diselenide nanoflakes decorated hierarchical 1D TiO2 fiber: A robust and highly efficient co-catalyst for hydrogen evolution reaction

Abstract Transitional metal dichalcogenide two-dimensional materials have revealed many astonishing properties including as a substitution of noble metals as a co-catalyst for hydrogen evolution reaction. Tin diselenide (SnSe2) is the one who also received substantial consideration in many fields due to low cost, earth-abundant and environment-friendly. However, the great challenge to make heterojunction with other semiconductor material to improve its efficiency for photocatalytic water splitting. For this purpose, we have prepared a 1D nanofiber of TiO2 by electrospinning and produced a needle-like structure on the fiber by following the alkali hydrothermal method. The chemical vapor deposition method (CVD) was adopted to load nanoflakes of SnSe2 on the branched fiber of TiO2 and make a strong heterojunction. The composite interpreted excellent photocatalytic performance by producing hydrogen about 0.95 mmol g−1 h−1 in comparison with branched TiO2 (0.47 mmol g−1 h−1) and conventional TiO2 fiber (0.35 mmol g−1 h−1). The photoluminescence, time decay fluorescent spectra and photoelectrochemical results ratified that SnSe2 not only reduces the charge recombination by increasing the transfer of electron but also provides the active site for hydrogen production as a cocatalyst. This study presents an inexpensive and environmentally friendly photocatalyst for hydrogen production without the use of noble metals.

Synergistic effect of one-dimensional silk nanofiber and two-dimensional graphene oxide composite membrane for enhanced water purification

Bombyx Mori silk-derived silk nanofiber (SNF; one dimensional, 1D) is assembled in the active functional group on the surface of graphene oxide (GO; two dimensional, 2D) composite membranes with an average thickness of 36–72 nm. The possibility of large-scale production through a simple chemical synthesis method with solutions of different pH levels of the SNF can be advantageous. The SNF/GOx composite membranes having a combination of 1D nanofiber and 2D materials possess a synthetic effect in the effective rejection rate of salt and dye. Investigation of the physicochemical properties of the SNF/GO composite membrane revealed that SNF interlaces the cavity I4 formed among the GO sheets to promote water flux. The hydrogen bonding interface between SNF and GO forms a specific water channel I3 to ensure the selectivity of Na2SO4 salt rejection. The 1D/2D synergy reveals a flux value of 43 LMH and a rejection value of 95% (up to 1000 ppm at 1.0 MPa pressure). The SNF/GO composite membrane exhibits good stability and increased operating pressure with increasing flux rate and constant rejection values. In addition, the SNF/GO5 wt% composite membrane exhibits excellent dye removal of up to 97%. The results demonstrate the potential of the SNF/GO5 wt% composite membrane to be used for water treatment in practical applications.

Efficient Energy Conversion and Storage Based on Robust Fluoride-Free Self-Assembled 1D Niobium Carbide in 3D Nanowire Network.

Owing to their high robustness and conductivity, 2D transition metal carbides and nitrides known as MXenes are considered as a promising material class for electrochemical catalysis, energy conversion, and storage applications. Nevertheless, conventional hazardous fluoride‐based synthesis routes and the intense intralayer bonding restrict the development of MXenes. Herein, a fluoride‐free, facile, and rapid method for synthesizing self‐assembled 1D architecture from an MXene‐based compound is reported. The MXene nanowire (NW) not only provides a robust connection to the flexible substrate but also effectively increases the electrochemically active surface area. The kinetics‐favorable structure yields a boosted performance for the hydrogen/oxygen evolution reaction and the intake of the zinc ion. The 1D NW based on MXene compound maintains high stability in a quite low overpotential of 236 mV for 24 h without detachment from the substrate and manifests an exceptional high‐power density of 420 W kg−1 over 150 cycles as a flexible aqueous zinc ion battery. This work paves a novel and non‐toxic synthesis method for the 1D nanofiber structure from MXene composition and demonstrates its multifunctional applications for energy conversion and storage.

Tin diselinide a stable co-catalyst coupled with branched TiO2 fiber and g-C3N4 quantum dots for photocatalytic hydrogen evolution

Transitional metal dichalcogenide two-dimensional materials have revealed many astonishing properties including the substitution of noble metals as a co-catalyst for hydrogen evolution reaction. Tin diselenide (SnSe2) is the one who also received substantial consideration in many fields due to low cost, earth-abundant and environment-friendly. However, the great challenge to make heterojunction with other semiconductor material to improve its efficiency for photocatalytic water splitting. For this purpose, we have prepared a 1D nanofiber of TiO2 by electrospinning and produced a needle-like structure on the fiber by following the alkali hydrothermal method. The chemical vapor deposition method (CVD) was adopted, first to load g-C3N4 QDs then nanoflakes of SnSe2 on the branched fiber of TiO2 and make a strong heterojunction. The composite interpreted excellent photocatalytic performance by producing hydrogen about 2375 μmol. g−1.h-1 having a quantum efficiency of HER more than 16 % at 420 nm. The photoluminescence, time decay fluorescent spectra and photoelectrochemical results ratified that SnSe2 not only reduces the charge recombination by increasing the transfer of electron but also provides an active site for hydrogen production as a cocatalyst. This study presents an inexpensive and environmentally friendly cocatalyst for hydrogen production as a substitution of noble metals.

Cerium oxide embedded bilayer separator enabling fast polysulfide conversion for high-performance lithium-sulfur batteries

Lithium sulfur (Li-S) batteries are considered as a promising candidate for next generation energy storage. However, the practical implementation of Li-S batteries is seriously hampered by the notorious shuttling of polysulfides. Current research mostly focuses on modifying polyolefin-based separators for immobilization of polysulfides. Herein we report a facile and efficient approach for fabrication of a functional bilayer separator based on 0D (nanocrystals)/1D (nanofibers) composite mats. The top layer comprises CeO2 nanocrystals spatially besieged by carbon nanofibers, serving as electrocatalysts to accelerate the reduction of polysulfides, meanwhile, acting as a dual-conductive upper current collector and a polysulfide inhibitor. The support layer maintains the structural integrity of the separator and allows the safe operation of Li-S batteries at high temperature. Consequently, the Li-S batteries with the bilayer separators exhibit a high initial reversible capacity of 1359 mA h g−1 at 0.2 C, high rate capability, superior cycling stability (with a capacity decay rate of 0.04% per cycle at 0.5 C over 300 cycles), and ultralow self-discharge.

Carbon-doped inorganic nanoassemblies as fillers to tailor the dielectric and energy storage properties in polymer-based nanocomposites

Polymer-based nanocomposites are excellent and promising in developing dielectric and energy storage applications, and one-dimensional (1D) nanofibers with large aspect ratio exhibit superiority in improving dispersibility, dielectric properties and energy storage performance of polymer nanocomposites as compared with their spherical counterparts. In this work, novel heterostructural carbon-doped inorganic nanoassemblies (TiO2/C nanofibers, NFs) were designed and synthesized in site via easy-processing electrospinning technique. Three different carbon contents of TiO2/C NFs were obtained as 2 wt%, 4.5 wt% and 13.6 wt% by regulating precalcination conditions, respectively. P(VDF-HFP) was chosen to incorporate with different nanofibers as prepared due to its relatively high dielectric constant. A comparative study on dielectric energy storage performance of the TiO2/C NFs/P(VDF-HFP) nanocomposites has been systematically presented. The results reveal that the dielectric constant and the energy density are significantly enhanced for nanocomposites with appropriate content of doped carbon inside NFs. At relatively low doping content, the carbon nanoparticles could well disperse in TiO2/C NFs for forming numerous micro-capacitors, which is beneficial for enhancing interfacial polarization and suppressing loss. This work provides insights into the effect of the carbon-doped nanoassemblies for further improving energy storage capability of polymer nanocomposites for high-performance device applications.

Building 1D nanofibers with controlled porosity and crystallinity for honeycomb-layered oxide to achieve fast ion kinetics and superior sodium storage performance

The exploration of sodium ion batteries (SIBs) cathodes with high voltage and high performance has stimulated the research on the honeycomb-layered oxides. However, their performance are severely restricted by the slow ion intercalation kinetics and inferior high rate capability. Herein, 1D nanofibers with controlled morphology and crystallinity have been constructed for the honeycomb-layered Na3Ni2BiO6 and Na3Ni2SbO6. The formation mechanisms of the nanofibers are probed. The significant effects of the porosity and particle crystallinity on ion transport kinetics and electrochemical properties of the oxide nanofibers are studied. Notably, the highly porous structure and low particle crystallinity are highly effective on promoting fast ion transport and improving high rate properties. Surprisingly, both modified nanofibers with uniform porous structure and low-crystallized nanoparticles achieve the better rate capability and faster ion transport capability than the reference samples. Moreover, the excellent sodium storage performance and stable high-rate cycling properties further demonstrate the high efficiency of 1D porous architecture on reversible sodium intercalation.