Publications by authors named "Xiangwu Zhang"

35 Publications

Disintegrable, transparent and mechanically robust high-performance antimony tin oxide/nanocellulose/polyvinyl alcohol thermal insulation films.

Carbohydr Polym 2021 Aug 7;266:118175. Epub 2021 May 7.

State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:

Polymer-based thermal insulation films are widely utilized to reduce the influence of solar radiation. However, current thermal insulation films face several challenges from poor thermal insulation performance and severe environmental pollution, which are caused by the non-disintegratability of polymer substrates. Here, cellulose nanofiber (CNF)/antimony tin oxide (ATO) hybrid films with and without polyvinyl alcohol (PVA) are presented and they can be used as window thermal barrier films and personal thermal management textiles. The hybrid films exhibit prominent thermal insulation performance, blocking 91.07% ultraviolet(UV) light, reflecting 95.19% near-infrared(NIR) light, and transmitting 44.89% visible(VIS) light. Meanwhile, the hybrid films demonstrate high thermal stability, high anti-UV aging stability, and robust mechanical properties. Moreover, the used-up hybrid films based on natural cellulose are of high disintegratability and recyclability. Our present work is anticipated to open up a new avenue for the fabrication of next-generation high-performance thermal insulation films with sustainable and environmentally friendly processes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.carbpol.2021.118175DOI Listing
August 2021

ZnO-assisted synthesis of lignin-based ultra-fine microporous carbon nanofibers for supercapacitors.

J Colloid Interface Sci 2021 Mar 27;586:412-422. Epub 2020 Oct 27.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27695-8301, United States. Electronic address:

Reducing the material size could be an effective approach to enhance the electrochemical performance of porous carbons for supercapacitors. In this work, ultra-fine porous carbon nanofibers are prepared by electrospinning using lignin/ polyvinylpyrrolidone as carbon precursor and zinc nitrate hexahydrate (ZNH) as an additive, followed by pre-oxidation, carbonization, and pickling processes. Assisted by the ZnO template, the pyrolytic product of ZNH, abundant micropores are yielded, leading to the formation of microporous carbon nanofibers with specific surface area (SSA) up to 1363 m g. The average diameter of the lignin-based ultra-fine porous carbon nanofibers (LUPCFs) is effectively controlled from 209 to 83 nm through adjusting the ZNH content. With good flexibility and self-standing nature, the LUPCFs could be directly cut into electrodes for use in supercapacitors. High accessible surface, enriched surface N/O groups, and reduced fiber diameters endow the LUPCFs-based electrodes with an excellent specific capacitance of 289 F g. The reduction of fiber diameters remarkably improves the rate performance of the LUPCFs and leads to a low relaxation time constant of 0.37 s. The high specific capacitance of 162 F g is maintained when the current density is increased from 0.1 to 20 A g. Besides, the fabricated LUPCFs show exceptional cycling stability in symmetrical supercapacitors, manifesting a promising application prospect in the next generation of supercapacitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2020.10.105DOI Listing
March 2021

Highly Thermally Stable, Green Solvent Disintegrable, and Recyclable Polymer Substrates for Flexible Electronics.

Macromol Rapid Commun 2020 Oct 24;41(19):e2000292. Epub 2020 Aug 24.

State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China.

Flexible electronics require its substrate to have adequate thermal stability, but current thermally stable polymer substrates are difficult to be disintegrated and recycled; hence, generate enormous electronic solid waste. Here, a thermally stable and green solvent-disintegrable polymer substrate is developed for flexible electronics to promote their recyclability and reduce solid waste generation. Thanks to the proper design of rigid backbones and rational adjustments of polar and bulky side groups, the polymer substrate exhibits excellent thermal and mechanical properties with thermal decomposition temperature (T ) of 430 °C, upper operating temperature of over 300 °C, coefficient of thermal expansion of 48 ppm K , tensile strength of 103 MPa, and elastic modulus of 2.49 GPa. Furthermore, the substrate illustrates outstanding optical and dielectric properties with high transmittance of 91% and a low dielectric constant of 2.30. Additionally, it demonstrates remarkable chemical and flame resistance. A proof-of-concept flexible printed circuit device is fabricated with this substrate, which demonstrates outstanding mechanical-electrical stability. Most importantly, the substrate can be quickly disintegrated and recycled with alcohol. With outstanding thermally stable properties, accompanied by excellent recyclability, the substrate is particularly attractive for a wide range of electronics to reduce solid waste generation, and head toward flexible and "green" electronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/marc.202000292DOI Listing
October 2020

Melt-spun modified poly (styrene-co-butyl acrylate) fiber as a carrier to support manganese oxide and its application in dye wastewater decolorization.

Environ Sci Pollut Res Int 2020 Aug 15;27(22):28209-28221. Epub 2020 May 15.

State Key Laboratory of Separation Membranes and Membrane Processes, College of Textile Science and Engineering, Tiangong University, Tianjin, 300387, China.

Polymer fiber, a kind of versatile material, has been widely used in many fields. However, emerging applications still urge us to develop some new kinds of fibers. Advanced oxidation processes (AOPs) have created a promising prospect for organic wastewater decontamination; thus, it is of important significance to design a kind of special fiber that can be applied in AOPs. In this work, a viable route is proposed to fabricate manganese oxide-supporting melt-spun modified poly (styrene-co-butyl acrylate) fiber, and the prepared fiber has an excellent activity to catalyze HO and O to decolorize dye-containing water. The results show that the decolorization of a cationic blue solution can be completely accomplished within 10 min with the prepared fiber as a catalyst, and its decolorization efficiency can reach up to 96.2% within 40 min. The concentration of total organic carbon can decrease from 20.3 to 12.3 mg/L. The prepared fiber can be reused five times without any loss in decolorization efficiency. Compared with other manganese oxide-based catalysts reported in the literature, the prepared fiber also shows many advantages in decolorizing methylene blue such as easy separation, mild reaction condition, and high decolorization efficiency. Therefore, we are confident that the fiber introduced in this study will exhibit a great application potential in the field of dye wastewater treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-020-09105-4DOI Listing
August 2020

Quantification on Growing Mass of Solid Electrolyte Interphase and Deposited Mn(II) on the Silicon Anode of LiMnO Full Lithium-Ion Cells.

ACS Appl Mater Interfaces 2019 Aug 23;11(31):27839-27845. Epub 2019 Jul 23.

Department of Chemistry , Tsinghua University , Beijing 100084 , China.

Silicon is considered to be one of the most important high-energy density anode materials for next-generation lithium-ion batteries. A large number of experimental studies on silicon anode have achieved better results, and greatly promoted its practical application potentiality, but almost of them are only tested in metal lithium half batteries. There is still an unavoidable question for commercial applications: what is the performance of the full cell composed of a silicon anode and a manganese-based material cathode? In this paper, the growing solid electrolyte interphase (SEI) and deposited manganese ions of the silicon anode's surface of the spinel lithium manganese oxide LiMnO/silicon full cells are quantitatively studied during electrochemical cycling, and the SEI performances are tested by differential scanning calorimetry to find out the reason for the rapid decline of reversible capacity in the LiMnO/silicon system. The experimental results show that manganese ions can make SEI films rapidly grow on the silicon anode and make SEI films more brittle, which results in lower Coulombic efficiency and rapid decline in capacity of the silicon anode.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b07400DOI Listing
August 2019

BODIPY-embedded electrospun materials in antimicrobial photodynamic inactivation.

Photochem Photobiol Sci 2019 Aug 31;18(8):1923-1932. Epub 2019 May 31.

Department of Chemistry, United States Air Force Academy, CO 80840, USA.

Drug-resistant pathogens, particularly those that result in hospital acquired infections (HAIs), have emerged as a critical priority for the World Health Organization. To address the need for self-disinfecting materials to counter the threat posed by the transmission of these pathogens from surfaces to new hosts, here we investigated if a cationic BODIPY photosensitizer, embedded via electrospinning into nylon and polyacrylonitrile (PAN) nanofibers, was capable of inactivating both bacteria and viruses via antimicrobial photodynamic inactivation (aPDI). Materials characterization, including fiber morphology and the degree of photosensitizer loading, was assessed by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), and demonstrated that the materials were comprised of nanofibers (125-215 nm avg. diameter) that were thermostable to >300 °C. The antimicrobial potencies of the resultant Nylon-BODIPY and PAN-BODIPY nanofiber materials were evaluated against four strains of bacteria recognized by the World Health Organization as either critical or high priority pathogens: Gram-positive strains methicillin-resistant S. aureus (MRSA; ATCC BAA-44) and vancomycin-resistant E. faecium (VRE; ATCC BAA-2320), and Gram-negative strains multidrug-resistant A. baumannii (MDRAB; ATCC BAA-1605) and NDM-1 positive K. pneumoniae (KP; ATCC BAA-2146). Our results demonstrated the detection limit (99.9999%; 6 log units reduction in CFU mL) photodynamic inactivation of three strains upon illumination (30-60 min; 40-65 ± 5 mW cm; 400-700 nm): MRSA, VRE, and MDRAB, but only minimal inactivation (47-75%) of KP. Antiviral studies employing PAN-BODIPY against vesicular stomatitis virus (VSV), a model enveloped virus, revealed complete inactivation. Taken together, the results demonstrate the potential for electrospun BODIPY-embedded nanofiber materials as the basis for pathogen-specific anti-infective materials, even at low photosensitizer loadings.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9pp00103dDOI Listing
August 2019

Binding Conductive Ink Initiatively and Strongly: Transparent and Thermally Stable Cellulose Nanopaper as a Promising Substrate for Flexible Electronics.

ACS Appl Mater Interfaces 2019 Jun 24;11(22):20281-20290. Epub 2019 May 24.

State Key Lab of Pulp and Paper Engineering , South China University of Technology , Guangzhou 510640 , China.

For flexible electronics, the substrates play key roles in ensuring their performance. However, most substrates suffer from weak bonding with the conductive ink and need additional aids. Here, inspired by the Ag-S bond theory, a novel cellulose nanopaper substrate is presented to improve the bond strength with the Ag nanoparticle ink through a facile printing method. The substrate is fabricated using thiol-modified nanofibrillated cellulose and exhibits excellent optical properties (∼85%@550 nm), ultra-small surface roughness (3.47 nm), and high thermal dimensional stability (up to at least 90 °C). Most importantly, it can attract Ag nanoparticles initiatively and bind them firmly, which enable the conductive ink to be printed without using the ink binder and form a strong substrate-ink bonding and maintain a stable conductivity of 2 × 10 Ω cm even after extensive peeling and bending. This work may lead to exploring new opportunities to fabricate high-performance flexible electronics using the newly developed nanopaper substrate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b04596DOI Listing
June 2019

SnS hollow nanofibers as anode materials for sodium-ion batteries with high capacity and ultra-long cycling stability.

Chem Commun (Camb) 2019 Jan;55(4):505-508

Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China.

In this study, a novel anode material of SnS hollow nanofibers (SnS HNFs) was rationally synthesized by a facile process and demonstrated to be a promising anode candidate for sodium-ion batteries. The synergetic effect of unique hollow and porous microstructures of SnS HNFs led to high capacity and ultra-long cycling stability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8cc07332eDOI Listing
January 2019

Electrospun Kraft Lignin/Cellulose Acetate-Derived Nanocarbon Network as an Anode for High-Performance Sodium-Ion Batteries.

ACS Appl Mater Interfaces 2018 Dec 14;10(51):44368-44375. Epub 2018 Dec 14.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science , North Carolina State University , Raleigh , North Carolina 27695-8301 , United States.

An innovative nanocarbon network material was synthesized from electrospun kraft lignin and cellulose acetate blend nanofibers after carbonization at 1000 °C in a nitrogen atmosphere, and its electrochemical performance was evaluated as an anode material in sodium-ion batteries. Apart from its unique network architecture, introduced carbon material possesses high oxygen content of 13.26%, wide interplanar spacing of 0.384 nm, and large specific surface area of 540.95 m·g. The electrochemical test results demonstrate that this new nanocarbon network structure delivers a reversible capacity of 340 mA h·g at a current density of 50 mA·g after 200 cycles and exhibits a high rate capacity by delivering a capacity of 103 mA h·g at an increased current density of 400 mA·g. The present work rendered an innovative approach for preparing nanocarbon materials for energy-storage applications and could open up new avenues for novel nanocarbon fabrication from green and environmentally friendly raw materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.8b13033DOI Listing
December 2018

Carbon-enhanced centrifugally-spun SnSb/carbon microfiber composite as advanced anode material for sodium-ion battery.

J Colloid Interface Sci 2019 Feb 30;536:655-663. Epub 2018 Oct 30.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, College of Textiles, North Carolina State University, Raleigh, NC 27695-8301, USA. Electronic address:

Antimony tin (SnSb) based materials have become increasingly attractive as a potential anode material for sodium-ion batteries (SIBs) owing to their prominent merit of high capacity. However, cyclic stability and rate capability of SnSb anodes are currently hindered by their large volume change during repeated cycling, which results in severe capacity fading. Herein, we introduce carbon-coated centrifugally-spun [email protected] microfiber (CMF) composites as high-performance anodes for SIBs that can maintain their structural stability during repeated charge-discharge cycles. The centrifugal spinning method was performed to fabricate [email protected] due to its high speed, low cost, and large-scale fabrication features. More importantly, extra carbon coating by chemical vapor deposition (CVD) has been demonstrated as an effective method to improve the capacity retention and Coulombic efficiency of the [email protected] anode. Electrochemical test results indicated that the as-prepared [email protected]@C anode could deliver a large reversible capacity of 798 mA h∙g at the 20th cycle as well as a high capacity retention of 86.8% and excellent Coulombic efficiency of 98.1% at the 100th cycle. It is, therefore, demonstrated that [email protected]@C composite is a promising anode material candidate for future high-performance SIBs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2018.10.101DOI Listing
February 2019

Reduced Graphene Oxide-Incorporated [email protected] Composites as Anodes for High-Performance Sodium-Ion Batteries.

ACS Appl Mater Interfaces 2018 Mar 9;10(11):9696-9703. Epub 2018 Mar 9.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science , North Carolina State University , Raleigh , North Carolina 27695-8301 , United States.

Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries because of the low cost and natural abundance of sodium resources. Nevertheless, low energy density and poor cycling stability of current SIBs unfavorably hinder their practical implementation for the smart power grid and stationary storage applications. Antimony tin (SnSb) is one of the most promising anode materials for next-generation SIBs attributing to its high capacity, high abundance, and low toxicity. However, the practical application of SnSb anodes in SIBs is currently restricted because of their large volume changes during cycling, which result in serious pulverization and loss of electrical contact between the active material and the carbon conductor. Herein, we apply reduced graphene oxide (rGO)-incorporated [email protected] nanofiber ([email protected]@CNF) composite anodes in SIBs that can sustain their structural stability during prolonged charge-discharge cycles. Electrochemical performance results shed light on that the combination of rGO, CNF, and SnSb alloy led to a high-capacity anode (capacity of 490 mAh g  at the 10th cycle) with a high capacity retention of 87.2% and a large Coulombic efficiency of 97.9% at the 200th cycle. This work demonstrates that the [email protected]@CNF composite is a potential and attractive anode material for next-generation, high-energy SIBs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.7b18921DOI Listing
March 2018

Biomass-derived porous carbon modified glass fiber separator as polysulfide reservoir for Li-S batteries.

J Colloid Interface Sci 2018 Mar 7;513:231-239. Epub 2017 Nov 7.

Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301, USA. Electronic address:

Biomass-derived porous carbon has been considered as a promising sulfur host material for lithium-sulfur batteries because of its high conductive nature and large porosity. The present study explored biomass-derived porous carbon as polysulfide reservoir to modify the surface of glass fiber (GF) separator. Two different carbons were prepared from Oak Tree fruit shells by carbonization with and without KOH activation. The KOH activated porous carbon (AC) provides a much higher surface area (796 m g) than pyrolized carbon (PC) (334 m g). The R factor value, calculated from the X-ray diffraction pattern, revealed that the activated porous carbon contains more single-layer sheets with a lower degree of graphitization. Raman spectra also confirmed the presence of sp-hybridized carbon in the activated carbon structure. The COH functional group was identified through X-ray photoelectron spectroscopy for the polysulfide capture. Simple and straightforward coating of biomass-derived porous carbon onto the GF separator led to an improved electrochemical performance in Li-S cells. The Li-S cell assembled with porous carbon modified GF separator (ACGF) demonstrated an initial capacity of 1324 mAh g at 0.2 C, which was 875 mAh g for uncoated GF separator (calculated based on the 2nd cycle). Charge transfer resistance (R) values further confirmed the high ionic conductivity nature of porous carbon modified separators. Overall, the biomass-derived activated porous carbon can be considered as a promising alternative material for the polysulfide inhibition in Li-S batteries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2017.11.016DOI Listing
March 2018

Excimer Ultraviolet-Irradiated Carbon Nanofibers as Advanced Anodes for Long Cycle Life Lithium-Ion Batteries.

Small 2016 Oct 12;12(38):5269-5275. Epub 2016 Aug 12.

Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China.

Carbon nanofibers (CNFs) bearing oxygen-containing functional groups and inhomogeneous nanopores are successfully prepared by excimer UV radiation. The CNFs demonstrate potential for use as an anodic material in rechargeable Li-ion batteries. Their improved electrochemical performances are attributed to the chemically bonded solid-electrolyte interface films on the CNF surface. This approach is also applicable to other carbonaceous electrode materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.201601158DOI Listing
October 2016

Nanoscale Porous Lithium Titanate Anode for Superior High Temperature Performance.

ACS Appl Mater Interfaces 2016 05 9;8(19):12127-33. Epub 2016 May 9.

Joint School of Nanoscience and Nanoengineering, North Carolina Agricultural and Technical State University , Greensboro, North Carolina 27401, United States.

In this work, nanoscale porous lithium titanate (LTO) anode material was synthesized by using aqueous spray drying method after ball milling. The size of the LTO nanoparticles was optimized to 200 nm because of its considerable moisture absorption levels for stable performance and its cooperation to make good quality electrodes found with testing. The electrochemical performance of the synthesized LTO nanoparticles was found to be very stable at high operating temperature (50 °C) and high current rate (5 C) which was worth noticing than its usual unfavorable behaviors (gas generation and surface phase transitions) at higher temperatures. In the postanalysis on the aged LTO cells, high-resolution-transmission electron microscope (HRTEM) and fast Fourier transform (FFT) measurements reveal that the LTO phase transitions are maintained to very thin surface level (3-5 nm) even after 500 cycles at 50 °C. Moreover, the synthesized LTO material showed stable cycling with a high capacity of 138.74 mA h g(-1) at 1 C rate and 111.53 mA h g(-1) at 5 C rate. Furthermore, high columbic efficiency and excellent capacity retention over 500 cycles at 50 °C was achieved. The enhanced electrochemical properties can be attributed to the increase in surface area and shortened Li(+) diffusion lengths because of the nanoscale primary particles and porous structure of the synthesized LTO particles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.6b00895DOI Listing
May 2016

Poly(vinyl Alcohol) Borate Gel Polymer Electrolytes Prepared by Electrodeposition and Their Application in Electrochemical Supercapacitors.

ACS Appl Mater Interfaces 2016 Feb 29;8(5):3473-81. Epub 2016 Jan 29.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University , Raleigh, North Carolina 27695-8301, United States.

Gel polymer electrolytes (GPEs) have been studied for preparing flexible and compact electrochemical energy storage devices. However, the preparation and use of GPEs are complex, and most GPEs prepared through traditional methods do not have good wettability with the electrodes, which retard them from achieving their performance potential. In this study, these problems are addressed by conceiving and implementing a simple, but effective, method of electrodepositing poly(vinyl alcohol) potassium borate (PVAPB) GPEs directly onto the surfaces of active carbon electrodes for electrochemical supercapacitors. PVAPB GPEs serve as both the electrolyte and the separator in the assembled supercapacitors, and their scale and shape are determined solely by the geometry of the electrodes. PVAPB GPEs have good bonding to the active electrode materials, leading to excellent and stable electrochemical performance of the supercapacitors. The electrochemical performance of PVAPB GPEs and supercapacitors can be manipulated simply by adjusting the concentration of KCl salt used during the electrodeposition process. With a 0.9 M KCl concentration, the as-prepared supercapacitors deliver a specific capacitance of 65.9 F g(-1) at a current density of 0.1 A g(-1) and retain more than 95% capacitance after 2000 charge/discharge cycles at a current density of 1 A g(-1). These supercapacitors also exhibit intelligent high voltage self-protection function due to the electrolysis-induced cross-linking effect of PVAPB GPEs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.5b11984DOI Listing
February 2016

Controlled Synthesis of Carbon Nanofibers Anchored with Zn(x)Co(3-x)O4 Nanocubes as Binder-Free Anode Materials for Lithium-Ion Batteries.

ACS Appl Mater Interfaces 2016 Feb 25;8(4):2591-9. Epub 2016 Jan 25.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University , Raleigh, North Carolina 27695-8301, United States.

The direct growth of complex ternary metal oxides on three-dimensional conductive substrates is highly desirable for improving the electrochemical performance of lithium-ion batteries (LIBs). We herein report a facile and scalable strategy for the preparation of carbon nanofibers (CNFs) anchored with ZnxCo3-xO4 (ZCO) nanocubes, involving a hydrothermal process and thermal treatment. Moreover, the size of the ZCO nanocubes was adjusted by the quantity of urea used in the hydrothermal process. Serving as a binder-free anode material for LIBs, the ZnCo2O4/CNFs composite prepared using 1.0 mmol of urea (ZCO/CNFs-10) exhibited excellent electrochemical performance with high reversible capacity, excellent cycling stability, and good rate capability. More specifically, a high reversible capacity of ∼600 mAh g(-1) was obtained at a current density of 0.5 C following 300 charge-discharge cycles. The excellent electrochemical performance could be associated with the controllable size of the ZCO nanocubes and synergistic effects between ZCO and the CNFs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.5b10340DOI Listing
February 2016

Photosensitizer-Embedded Polyacrylonitrile Nanofibers as Antimicrobial Non-Woven Textile.

Nanomaterials (Basel) 2016 Apr 20;6(4). Epub 2016 Apr 20.

Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.

Toward the objective of developing platform technologies for anti-infective materials based upon photodynamic inactivation, we employed electrospinning to prepare a non-woven textile comprised of polyacrylonitrile nanofibers embedded with a porphyrin-based cationic photosensitizer; termed PAN-Por. Photosensitizer loading was determined to be 34.8 nmol/mg material; with thermostability to 300 °C. Antibacterial efficacy was evaluated against four bacteria belonging to the ESKAPE family of pathogens (; vancomycin-resistant ; ; and ), as well as . Our results demonstrated broad photodynamic inactivation of all bacterial strains studied upon illumination (30 min; 65 ± 5 mW/cm²; 400-700 nm) by a minimum of 99.9996+% (5.8 log units) regardless of taxonomic classification. PAN-Por also inactivated human adenovirus-5 (~99.8% reduction in PFU/mL) and vesicular stomatitis virus (>7 log units reduction in PFU/mL). When compared to cellulose-based materials employing this same photosensitizer; the higher levels of photodynamic inactivation achieved here with PAN-Por are likely due to the combined effects of higher photosensitizer loading and a greater surface area imparted by the use of nanofibers. These results demonstrate the potential of photosensitizer-embedded polyacrylonitrile nanofibers to serve as scalable scaffolds for anti-infective or self-sterilizing materials against both bacteria and viruses when employing a photodynamic inactivation mode of action.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/nano6040077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5302559PMC
April 2016

NiCu Alloy Nanoparticle-Loaded Carbon Nanofibers for Phenolic Biosensor Applications.

Sensors (Basel) 2015 Nov 20;15(11):29419-33. Epub 2015 Nov 20.

Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, China.

NiCu alloy nanoparticle-loaded carbon nanofibers (NiCuCNFs) were fabricated by a combination of electrospinning and carbonization methods. A series of characterizations, including SEM, TEM and XRD, were employed to study the NiCuCNFs. The as-prepared NiCuCNFs were then mixed with laccase (Lac) and Nafion to form a novel biosensor. NiCuCNFs successfully achieved the direct electron transfer of Lac. Cyclic voltammetry and linear sweep voltammetry were used to study the electrochemical properties of the biosensor. The finally prepared biosensor showed favorable electrocatalytic effects toward hydroquinone. The detection limit was 90 nM (S/N = 3), the sensitivity was 1.5 µA µM(-1), the detection linear range was 4 × 10(-7)-2.37 × 10(-6) M. In addition, this biosensor exhibited satisfactory repeatability, reproducibility, anti-interference properties and stability. Besides, the sensor achieved the detection of hydroquinone in lake water.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s151129419DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4701341PMC
November 2015

High performance carbon nanotube--polymer nanofiber hybrid fabrics.

Nanoscale 2015 Oct;7(40):16744-54

Department of Textile Engineering Chemistry and Science, North Carolina State University, Campus Box 8301, Raleigh, NC 27695, USA.

Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m(-2) exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5nr02732bDOI Listing
October 2015

Carbon-Confined SnO2-Electrodeposited Porous Carbon Nanofiber Composite as High-Capacity Sodium-Ion Battery Anode Material.

ACS Appl Mater Interfaces 2015 Aug 13;7(33):18387-96. Epub 2015 Aug 13.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University , Raleigh, North Carolina 27695-8301, United States.

Sodium resources are inexpensive and abundant, and hence, sodium-ion batteries are promising alternative to lithium-ion batteries. However, lower energy density and poor cycling stability of current sodium-ion batteries prevent their practical implementation for future smart power grid and stationary storage applications. Tin oxides (SnO2) can be potentially used as a high-capacity anode material for future sodium-ion batteries, and they have the advantages of high sodium storage capacity, high abundance, and low toxicity. However, SnO2-based anodes still cannot be used in practical sodium-ion batteries because they experience large volume changes during repetitive charge and discharge cycles. Such large volume changes lead to severe pulverization of the active material and loss of electrical contact between the SnO2 and carbon conductor, which in turn result in rapid capacity loss during cycling. Here, we introduce a new amorphous carbon-coated SnO2-electrodeposited porous carbon nanofiber ([email protected]@C) composite that not only has high sodium storage capability, but also maintains its structural integrity while ongoing repetitive cycles. Electrochemical results revealed that this SnO2-containing nanofiber composite anode had excellent electrochemical performance including high-capacity (374 mAh g(-1)), good capacity retention (82.7%), and large Coulombic efficiency (98.9% after 100th cycle).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.5b04338DOI Listing
August 2015

Sulfur gradient-distributed CNF composite: a self-inhibiting cathode for binder-free lithium-sulfur batteries.

Chem Commun (Camb) 2014 Sep;50(71):10277-80

Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695, USA.

A self-inhibiting, gradient sulfur structure was designed and developed by the synthesis of a carbon nanofiber-sulphur composite via sulfur vapor deposition method for use as a binder-free sulfur cathode, exhibiting high sulfur loading (2.6 mg cm(-2)) and high sulfur content (65%) with a stable capacity of >700 mA h g(-1).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4cc04970eDOI Listing
September 2014

Chamber-confined silicon-carbon nanofiber composites for prolonged cycling life of Li-ion batteries.

Nanoscale 2014 Jul;6(13):7489-95

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301, USA.

Silicon is a promising high capacity (4200 mA h g(-1)) anode material for lithium ion batteries but the significant volume change (over 300%) of silicon during lithiation/delithiation remains a challenge in terms of silicon pulverization and solid-electrolyte-interphase (SEI) accumulation in the silicon composite electrode. To alleviate the volumetric change of silicon, we built a flexible and self-supporting carbon-enhanced carbon nanofiber (CNF) structure with vacant chamber to encapsulate Si nanoparticles (vacant [email protected]@C). This composite was tested directly without any polymer and current collector. The confined vacant chamber allowed the increasing volume of silicon and SEI accumulates to be well retained for a long cycle life. This chamber-confined silicon-carbon nanofiber composite exhibited an improved performance in terms of good cycling performance (620 mA h g(-1)), high coulombic efficiency (99%), and good capacity retention (80%) after 200 cycles. This self-supported silicon-carbon nanofiber structure showed high flexibility and good electrochemical performance for the potential as flexible electrode for lithium-ion batteries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4nr00518jDOI Listing
July 2014

Aligned carbon nanotube-silicon sheets: a novel nano-architecture for flexible lithium ion battery electrodes.

Adv Mater 2013 Sep 1;25(36):5109-14. Epub 2013 Aug 1.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC, 27695, USA.

Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201301920DOI Listing
September 2013

Carbon-coated Si nanoparticles dispersed in carbon nanotube networks as anode material for lithium-ion batteries.

ACS Appl Mater Interfaces 2013 Jan 14;5(1):21-5. Epub 2012 Dec 14.

Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, United States.

Si has the highest theoretical capacity among all known anode materials, but it suffers from the dramatic volume change upon repeated lithiation and delithiation processes. To overcome the severe volume changes, Si nanoparticles were first coated with a polymer-driven carbon layer, and then dispersed in a CNT network. In this unique structure, the carbon layer can improve electric conductivity and buffer the severe volume change, whereas the tangled CNT network is expected to provide additional mechanical strength to maintain the integrity of electrodes, stabilize the electric conductive network for active Si, and eventually lead to better cycling performance. Electrochemical test result indicates the carbon-coated Si nanoparticles dispersed in CNT networks show capacity retention of 70% after 40 cycles, which is much better than the carbon-coated Si nanoparticles without CNTs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am3027597DOI Listing
January 2013

In situ TEM study of lithiation behavior of silicon nanoparticles attached to and embedded in a carbon matrix.

ACS Nano 2012 Sep 28;6(9):8439-47. Epub 2012 Aug 28.

Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.

Rational design of silicon and carbon nanocomposite with a special topological feature has been demonstrated to be a feasible way for mitigating the capacity fading associated with the large volume change of silicon anode in lithium ion batteries. Although the lithiation behavior of silicon and carbon as individual components has been well understood, lithium ion transport behavior across a network of silicon and carbon is still lacking. In this paper, we probe the lithiation behavior of silicon nanoparticles attached to and embedded in a carbon nanofiber using in situ TEM and continuum mechanical calculation. We found that aggregated silicon nanoparticles show contact flattening upon initial lithiation, which is characteristically analogous to the classic sintering of powder particles by a neck-growth mechanism. As compared with the surface-attached silicon particles, particles embedded in the carbon matrix show delayed lithiation. Depending on the strength of the carbon matrix, lithiation of the embedded silicon nanoparticles can lead to the fracture of the carbon fiber. These observations provide insights on lithium ion transport in the network-structured composite of silicon and carbon and ultimately provide fundamental guidance for mitigating the failure of batteries due to the large volume change of silicon anodes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/nn303312mDOI Listing
September 2012

α-Fe2O3 nanoparticle-loaded carbon nanofibers as stable and high-capacity anodes for rechargeable lithium-ion batteries.

ACS Appl Mater Interfaces 2012 May 2;4(5):2672-9. Epub 2012 May 2.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, USA.

α-Fe(2)O(3) nanoparticle-loaded carbon nanofiber composites were fabricated via electrospinning FeCl(3)·6H(2)O salt-polyacrylonitrile precursors in N,N-dimethylformamide solvent and the subsequent carbonization in inert gas. Scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and elemental analysis were used to study the morphology and composition of α-Fe(2)O(3)-carbon nanofiber composites. It was indicated that α-Fe(2)O(3) nanoparticles with an average size of about 20 nm have a homogeneous dispersion along the carbon nanofiber surface. The resultant α-Fe(2)O(3)-carbon nanofiber composites were used directly as the anode material in rechargeable lithium half cells, and their electrochemical performance was evaluated. The results indicated that these α-Fe(2)O(3)-carbon nanofiber composites have high reversible capacity, good capacity retention, and acceptable rate capability when used as anode materials for rechargeable lithium-ion batteries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am300333sDOI Listing
May 2012

Carbon nanotube-loaded electrospun LiFePO4/carbon composite nanofibers as stable and binder-free cathodes for rechargeable lithium-ion batteries.

ACS Appl Mater Interfaces 2012 Mar 10;4(3):1273-80. Epub 2012 Feb 10.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, 2401 Research Drive, Raleigh, NC 27695-8301, USA.

LiFePO(4)/CNT/C composite nanofibers were synthesized by using a combination of electrospinning and sol-gel techniques. Polyacrylonitrile (PAN) was used as the electrospinning media and carbon source. Functionalized CNTs were used to increase the conductivity of the composite. LiFePO(4) precursor materials, PAN and functionalized CNTs were dissolved or dispersed in N,N-dimethylformamide separately and they were mixed before electrospinning. LiFePO(4) precursor/CNT/PAN composite nanofibers were then heat-treated to obtain LiFePO(4)/CNT/C composite nanofibers. Fourier transform infrared spectroscopy measurements were done to demonstrate the functionalization of CNTs. The structure of LiFePO(4)/CNT/C composite nanofibers was determined by X-ray diffraction analysis. The surface morphology and microstructure of LiFePO(4)/CNT/C composite nanofibers were characterized using scanning electron microscopy and transmission electron microscopy. Electrochemical performance of LiFePO(4)/CNT/C composite nanofibers was evaluated in coin-type cells. Functionalized CNTs were found to be well-dispersed in the carbonaceous matrix and increased the electrochemical performance of the composite nanofibers. As a result, cells using LiFePO(4)/CNT/C composite nanofibers have good performance, in terms of large capacity, extended cycle life, and good rate capability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am201527rDOI Listing
March 2012

Multifunctional ZnO/Nylon 6 nanofiber mats by an electrospinning-electrospraying hybrid process for use in protective applications.

Sci Technol Adv Mater 2011 Oct 7;12(5):055004. Epub 2011 Sep 7.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301, USA.

ZnO/Nylon 6 nanofiber mats were prepared by an electrospinning-electrospraying hybrid process in which ZnO nanoparticles were dispersed on the surface of Nylon 6 nanofibers without becoming completely embedded. The prepared ZnO/Nylon 6 nanofiber mats were evaluated for their abilities to kill bacteria or inhibit their growth and to catalytically detoxify chemicals. Results showed that these ZnO/Nylon 6 nanofiber mats had excellent antibacterial efficiency (99.99%) against both the Gram-negative and Gram-positive bacteria. In addition, they exhibited good detoxifying efficiency (95%) against paraoxon, a simulant of highly toxic chemicals. ZnO/Nylon 6 nanofiber mats were also deposited onto nylon/cotton woven fabrics and the nanofiber mats did not significantly affect the moisture vapor transmission rates and air permeability values of the fabrics. Therefore, ZnO/Nylon 6 nanofiber mats prepared by the electrospinning-electrospraying hybrid process are promising material candidates for protective applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1468-6996/12/5/055004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5074436PMC
October 2011

Sulfonated polystyrene fiber network-induced hybrid proton exchange membranes.

ACS Appl Mater Interfaces 2011 Sep 24;3(9):3732-7. Epub 2011 Aug 24.

Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, United States.

A novel type of hybrid membrane was fabricated by incorporating sulfonated polystyrene (S-PS) electrospun fibers into Nafion for the application in proton exchange membrane fuel cells. With the introduction of S-PS fiber mats, a large amount of sulfonic acid groups in Nafion aggregated onto the interfaces between S-PS fibers and the ionomer matrix, forming continuous pathways for facile proton transport. The resultant hybrid membranes had higher proton conductivities than that of recast Nafion, and the conductivities were controlled by selectively adjusting the fiber diameters. Consequently, hybrid membranes fabricated by ionomers, such as Nafion, incorporated with ionic-conducting nanofibers established a promising strategy for the rational design of high-performance proton exchange membranes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am2009184DOI Listing
September 2011

Electrospun carbon-tin oxide composite nanofibers for use as lithium ion battery anodes.

ACS Appl Mater Interfaces 2011 Jul 10;3(7):2534-42. Epub 2011 Jun 10.

Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States.

Composite carbon-tin oxide (C-SnO(2)) nanofibers are prepared by two methods and evaluated as anodes in lithium-ion battery half cells. Such an approach complements the long cycle life of carbon with the high lithium storage capacity of tin oxide. In addition, the high surface-to-volume ratio of the nanofibers improves the accessibility for lithium intercalation as compared to graphite-based anodes, while eliminating the need for binders or conductive additives. The composite nanofibrous anodes have first discharge capacities of 788 mAh g(-1) at 50 mA g(-1) current density, which are greater than pure carbon nanofiber anodes, as well as the theoretical capacity of graphite (372 mAh g(-1)), the traditional anode material. In the first protocol to fabricate the C-SnO(2) composites, tin sulfate is directly incorporated within polyacrylonitrile (PAN) nanofibers by electrospinning. During a thermal treatment the tin salt is converted to tin oxide and the polymer is carbonized, yielding carbon-SnO(2) nanofibers. In the second approach, we soak the nanofiber mats in tin sulfate solutions prior to the final thermal treatment, thereby loading the outer surfaces with SnO(2) nanoparticles and raising the tin content from 1.9 to 8.6 wt %. Energy-dispersive spectroscopy and X-ray diffraction analyses confirm the formation of conversion of tin sulfate to tin oxide. Furthermore, analysis with Raman spectroscopy reveals that the additional salt soak treatment from the second fabrication approach increases in the disorder of the carbon structure, as compared to the first approach. We also discuss the performance of our C-SnO(2) compared with its theoretical capacity and other nanofiber electrode composites previously reported in the literature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am2004015DOI Listing
July 2011
-->