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A ZnS nano-sorbent to remove copper(II) and lead(II) ions from aqueous solutions was prepared via a hydrothermal reaction and characterized by X-ray diffraction. The zinc sulfide nanoparticle size was determined to be 7.0 ± 0.22 nm. The effects of pH, light conditions, time, capacity, and interferences on the zinc sulfide ability to remove copper(II) and lead(II) ions from aqueous solutions were investigated. pH studies showed that pH 5 was the optimal value for zinc sulfide binding both copper(II) and lead(II) ions. Under ambient light, the binding of both ions occurred within the first 5 min. Binding capacities ranged from 116.2 to 243.9 mg/g for copper(II), 39.1 to 147.1 mg/g for lead(II) ions, and 36.1–79.4 mg/g for lead(II) ions in the dark over temperature range from 4 to 45 °C. The thermodynamic parameters showed that the binding process for both copper(II) and lead(II) ions was either spontaneous or close to equilibrium. Light conditions were also investigated in the context of cation interference and showed that the presence of hard cations had no effect on the binding of lead(II) ions. On the other hand, the presence of hard cations showed small decrease in the binding of copper(II) ions.

Centrifugally spun polyacrylonitrile (PAN) microfibers surface-coated with Co3O4 nanoparticles were prepared as precursors to produce coated Co3O4 carbon-fiber (CCF) composites for lithium-ion battery anodes. The Co3O4/C composite-fiber anodes were obtained after the stabilization of surface-coated Co3O4/PAN fibers at 200 °C for four hours, and subsequent carbonization at 600 °C for 6 hours. The electrochemical performance of the Co3O4/C composite-fiber anode with different active material loading was evaluated by using galvanostatic charge/discharge, rate performance, cyclic voltammetry, and electrochemical impedance spectroscopy experiments. The CCF anode delivered a specific charge capacity of 632 and 420 mAh g−1 after 100 cycles at 100 and 200 mA g−1, respectively, and exhibited good rate capability. An improved electrochemical performance of the CCF was observed compared to the carbon-fiber (CF) anode (300 mAh g−1), which was attributed to the interaction between CFs and Co3O4 nanoparticles. The synthesis method presented in this work can provide an effective avenue for the fabrication of surface coated-fiber materials, including free-standing anode materials for lithium-ion batteries with increased specific capacity and improved electrochemical performance compared to carbon-fiber electrodes.

Poly(vinylpyrrolidone) (PVP) nanofibers were prepared by a centrifugal spinning technique, namely Forcespinning®. The effect of the molecular weight of PVP and selected solvents (N,N-dimethylformamide, DMF) and water) were studied in reference to the ultimate morphology of the developed nanofibers. For the analyzed molecular weights and selected solvents, long, continuous and bead-free nanofibers were obtained as depicted by scanning electron microscopy analysis. It was observed that the molecular weight and solvent selection did have an effect on ultimate fiber diameter. The smallest fiber diameters (27 nm for Mw 1,300,000 and 58 nm for Mw 360,000) were obtained from samples prepared with DMF as solvent. As for the influence of molecular weights, results revealed that solutions prepared with PVP of Mw 360,000 in both solvents resulted in thicker diameter compared to PVP of Mw 1,300,000 though samples prepared with this higher molecular weight presented a much larger standard deviation. Fibers obtained from PVP solutions (Mw 1,300,000) in DMF exhibited a highly homogenous porous surface while those prepared from aqueous solutions showed smooth fiber surface.

The present work focuses on the large-scale production of Fe2O3/C, TiO2/C and Fe2O3/TiO2/C composite fibers by centrifugal spinning (CF). Fe2O3/PVP, TiO2/PVP, and Fe2O3/TiO2/PVP precursor solutions were prepared and centrifugally spun at 7200 RPM to obtain precursor micro fibrous mats. The precursor fibers were then stabilized in air at 200 °C for 3 hours followed by calcination in Argon atmosphere at 500 °C for 4 hours to obtain composite carbon fibers. In addition, TiO2-slurry based electrode was prepared from mixing 70% of TiO2 active material with 20 % carbon black and PAN binder. The TiO2 electrode delivered a good electrochemical performance and cyclability. The Fe2O3/C, TiO2/C and Fe2O3 /TiO2/C composite-fiber anodes demonstrated a stable cycling performance with a discharge capacity of 200, 144, and 235 mAh g-1 respectively after 100 cycles at 100 mAh g-1 with the exception of the first cycle which was tested at 50 mAh g-1. The high surface area of the centrifugally spun composite fibers resulted in high irreversible capacity at the first cycle compared the slurry-based electrode. Although these composite electrodes exhibited stable capacity and a decent cyclability, further work is required to improve the Coulombic efficiency of composite-fiber electrodes and enhance their overall electrochemical performance and rate capability.

α-Fe2O3 hollow nanofibers with wall thicknesses of 45 ± 16 nm were fabricated via centrifugal spinning of a solution containing Fe(NO3)3·9H2O and polyvinylpyrrolidone. These fibers were subjected to mechanical milling and mixed in ethanol. Polyacrylonitrile (PAN) fiber mats were also fabricated by centrifugal spinning from dimethylformamide-based solutions. The as-prepared PAN fibrous mats were dipped in the iron-oxide suspension. The coated PAN membranes were then subjected to a heat treatment which yielded carbon fibers coated with Fe3O4 nanoparticles. Both pure carbon fibers (carbonized PAN fibers) and Fe3O4/C composite fibers were used as anode materials in Li-ion batteries. The Fe3O4/C composite anode exhibited high specific capacity and good cycle stability when compared to that of the carbon-fiber electrode. An initial discharge capacity (Li insertion) of 882 mAh g−1 was obtained for the Fe3O4/C composite fibers with promising cycle performance and rate capability. These composite fibers show promising applications as electrode materials in high-performance rechargeable lithium-ion batteries.

Nanoparticles (NPs) have been variously used in the areas of agriculture, biomedicine, nanotechnology, human health, and biological applications. The potential human and animal exposures to NPs are increasing as the range of consumer products containing engineered NPs increases over time. Thus, there has been a surge in research focusing on the interactions and toxicity of NPs with living organisms. The toxicity of metallic nanoparticles such as Ag has been extensively studied in bacterial cell studies. However, one of the most widely used nanomaterials includes metal oxide NPs. Metal oxide NPs are generally utilized for their semiconductor properties. NPs such as TiO2, ZnO, and CuO have been used in different applications including photocatalysis, energy storage, and biomedical applications. This chapter focuses on the interactions of TiO2, ZnO, and CuO NPs and their adverse effects on live organisms and cells. Special emphasis is given in this chapter to discuss recent results reported on the interactions of algal cells: Diatoms/plankton species, bivalve species, fish species. Some studies on the exposure of human cell lines and mammalian models are also included. The common effects of metal oxide nanoparticles exhibited across the species of organisms include, predominately, oxidative stress and decreased cellular viability. To gain a comprehensive picture of NP toxicity, the identification of surfactant toxicity is important, as many of the stabilizing agents used in NP synthesis are highly toxic. Finally, the stability of the NPs is important to the discussion of NP toxicity. Stability of NPs and NP toxicity can be seen as the toxicological differences in the phases of TiO2. Rutile is the most thermodynamically stable form of TiO2 and is less toxic than the anatase form of TiO2. As well, CuO and ZnO NPs are sparingly soluble in aqueous solution, which can generate Cu2+ and Zn2+ ions in solution. Both Cu2+ and Zn2+ ions are toxic and complicate the interpretations of CuO and ZnO NP toxicity.

We report results on the Forcespinning (FS) of Polyvinylpyrrolidone (PVP) solutions for the preparation/fabrication of carbon fibers (CFs) as anodes for sodium ion batteries (SIBs). The objective of this study is to manipulate the microstructure of the CFs to improve the intercalation kinetics of the sodium ion into the CF structure. The as prepared CFs were porous with an average fiber diameter of 1.99 µm. The electrochemical performance of the CF anodes was investigated by carrying out galvanostatic charge/discharge and impedance experiments on Na+ half cells. The results show that the CF anodes exhibited a high discharge capacity of 330 mAh g−1 at the first discharge (Sodium insertion) and reversible capacity of 88 mAh g−1 after 100 cycles at a current density of 100 mA g−1. The results are promising and show that Forcespun CFs are a stepping stone for anode materials in SIBs.

We present results on the Forcespinning (FS) of PAN solution precursors for the mass production of metal/oxides carbon (MO/C) composite microfibers as anode materials for Lithium-ion batteries. The MO/C composite microfiber anodes are produced using a scalable technique (FS) and subsequent thermal treatment (calcination). The composite anodes were porous and flexible. The flexible composite microfibers were directly used as binder free electrodes in lithium-ion batteries. Mixed organic/ionic liquid electrolytes (MOILEs) were employed in Lithium ion cell cycling studies with the MO/C composite fibers and composite fiber cathodes to investigate the electrochemical and cycling performance of the Li-ion cells. The ionic conductivity of MOILEs and the electrochemical performance of LIB cells were investigated at different temperatures and current rates. 1-Ethyl-3-Methyl-imidazolium Lithium bis(trifluoromethanesulfonyl) imide (EMI-TFSI) ionic liquid was synthesized in our laboratory by reacting the EMI cation and TFSI ion in a 1:1 mole ratio. The EMI-TFSI ionic liquid and LiTFSI salt were mixed with organic liquids (Ethylene carbonate (EC) dimethyl carbonate (DMC) and Succinonitril (SN) to improve the ionic transport of the electrolyte during the charge/discharge cycles. The MO/C composite electrodes delivered a good electrochemical performance and Columbic efficiency when used as half and full cells. The electrochemical performance of the Forcespun composite fiber cathodes was also investigated in half-cell cycling.

In this study, Forcespinning is used to produce TiS2/carbon composite fibers for lithium ion battery anodes. The use of a 2-D layered structure of TiS2 nanoparticles in the carbon fiber matrix can greatly accommodate more Li ions between the layers leading to increased specific capacity, improved stability and good electrochemical performance of the anode after prolonged charge/ discharge cycles. The TiS2/C composite fiber anodes delivered a discharge and charge capacities at the first cycle of 900 mAhg-1 and 600 mAhg-1, respectively. Some of the TiS2 nanoparticles turned into a 2-D layered structure of TiO2 nanoparticles after the oxidation process in air environment. The TiS2/C composite fibers show an improvement in the electrochemical performance over the commercially graphite anodes of 372 mAhg-1. When was used as anode for LIBs, the layered structure of TiO2 composite fibers showed charge capacity of 250 mAhg-1 after 100 cycles at 50 mAg-1.

We present results on the Forcespinning (FS) of MoS2/PAN and MoO2/PAN solution precursors for the mass production of MoS2/C and MoO2/C composite fibers for use as binder-free and freestanding anodes for lithium-ion and sodium-ion batteries. The binary composite microfiber electrodes were prepared using a scalable technique (FS) and subsequent thermal treatment. Scanning Electron Microscope (SEM) images of the composite microfibers showed nanoparticles of the MoS2 and MoO2 active materials embedded in the surface of the fibers. The composite microfiber preparation process involved FS of the MoS2/PAN and MoO2/C solution precursors into microfibers and subsequent stabilization in air at 280oC and calcination at 700oC for MoO2/C and 810oC for MoS2/C under an inert atmosphere. The flexible composite microfibers were directly used as working electrode in lithium-ion and sodium-ion batteries without a current collector, conducting additives, or binder. The MoS2/C and MoO2/C composite fiber electrodes delivered a good electrochemical performance and Coulombic efficiency when used for lithium-ion batteries. The MoS2/C electrodes delivered an initial discharge (insertion) capacity of 650 mAhg-1, with a corresponding charge capacity of 425 mAhg-1 at a current density of 100 mAg-1. In the subsequent cycles, the MoS2/C electrodes stabilize at about 50 cycles and maintain a stable specific capacity of about 245 mAhg-1, in the last 5 cycles there is slight recovery with a final specific capacity of 255 mAhg-1. The MoO2/C composite anode delivered a reversible capacity of 356 mAhg-1 at 100 mAg-1, stabilizing at 245 mAhg-1 after 100 cycles. The results presented in this work showed that the MoS2/C and MoO2/C composite fibers have good reversible capacity, good capacity retention and acceptable rate performance when used as anode materials for rechargeable lithium ion batteries.

Centrifugally spun polyacrylonitrile (PAN) microfibers surface-coated with Co3O4 nanoparticles (NPs) were prepared as precursors to produce coated Co3O4 carbon-composite fibers. The Co3O4/C composite fibers were obtained through a staged heating process during which the Co3O4PAN precursor fibers were stabilized over four hours at 200 °C, and subsequently the stabilized fibers were carbonized for six hours at 600 °C. The synthesis process presented in this work provides an effective strategy for the fabrication of surface coated-fiber materials, including composite fibers with good structure and morphology. The characterization of the Co3O4/C composite fibers was performed using SEM, EDS, XPS, XRD and BET. The SEM data indicated the fibers were micron-sized in diameter with a non-homogenous distribution of the Co3O4 NPs on both the Co3O4-PAN and the CO3O4-Carbon composite fibers. The EDS mapping of the cobalt showed it to be distributed throughout the samples on the surface, but areas of high concentrations of particles were observed. The powder XRD data showed a reduction of the Co(III)/Co(II) starting material into a combination of Co-metal and CoO. The XRD results were confirmed by the Co 2P XPS data, which showed a change from the pure Co3O4 NPs to a combination of Co(III), Co(II) and Co-metal. In addition, the binding of the Co3O4 nanoparticles to the PAN fibers before carbonization showed a change in the chemical environment, which included attachment through an N ligand on the fibers.

In recent years, there has been growing concern regarding the use of petroleum-based lubricants. This concern has generated interest in readily biodegradable fluids such as vegetable oils. The present work evaluated the rheological and tribological characteristics of sunflower oil modified with silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles as lubricant additives at different concentrations. A parallel plate rheometer was used to evaluate the effects of concentration and shear rate on the shear viscosity, and the experimental data was compared with conventional models. The wear protection and friction characteristics of the oil-formulations were evaluated by conducting block-on-ring sliding tests. Surface analysis-based instruments, including scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and profilometry, were used to characterize the morphology and structure of the worn surfaces. The experimental results showed that the coefficient of friction decreased with the addition of SiO2 and TiO2 nanoparticles by 77.7% and 93.7%, respectively when compared to base sunflower oil. Furthermore, the volume loss was lowered by 74.1% and 70.1%, with the addition of SiO2 and TiO2 nanoparticles, respectively. Based on the experimental results, the authors conclude that modified sunflower oil enhanced with nanoparticles has the potential for use as a good biodegradable lubricant.

Nanofibers (NFs) and composite NFs have been widely used as electrode and separator materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to their high surface-area-to-volume ratio and versatility of their morphologies. The majority of carbon-fibers (CFs) anodes have been prepared by electrospinning and subsequent thermal treatment. Nevertheless, the low fiber yield and safety hazards associated with this method have raised concerns and limited the commercialization of composite CF anodes. Fiber and nanofiber processing methods such as centrifugal spinning can overcome low productivity and eliminate the use of a high voltage to produce fibers. In the present work, centrifugally spun fibers with alloying, transition metal oxides, and transition metal sulfite-based materials are presented and discussed for potential use as anode materials in LIBs and SIBs. Emphasis is given on the centrifugal spinning process and its effects on fiber formation, morphology, and structure of these nanocomposite anodes.

Nanocrystalline complex oxide scintillators have emerged for use in X-ray and gamma-ray detection in recent years. Here the doping concentration dependence of europium-doped lanthanum zirconate (La2Zr2O7:xmol%Eu3+, x = 1 to 35) nanoparticles (NPs) were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), and optically and X-ray excited luminescence. Spectroscopic methods revealed a gradual increase in disorder from the ordered pyrochlore structure to the defect fluorite structure as the Eu3+ concentration increases. They showed red luminescence under charge transfer band (258 nm), and Eu3+ 4f-4f bands (322, 394 and 465 nm) excitation with optical intensity dependent on the Eu3+ doping concentration and not quenching up to 5% Eu3+ doping concentration. The quantum yield of the red emission was found to depend on the Eu3+ doping concentration and excitation wavelength. Moreover, these La2Zr2O7:x%Eu3+ NPs demonstrated an atypical Eu3+ related scintillating response with a red emission under high-energy X-ray excitation with the scintillation intensity also depending on the Eu3+ doping concentration. Finally, the irradiation damage behavior induced by the excitation source was representatively examined for the La2Zr2O7:5%Eu3+ NPs. It is expected that the current study will pave the way for future research of nanoscintillators.

The development of alternative anode materials out of flexible composite nanofibers has seen a growing interest. In this paper, binary carbon nanofiber electrodes of SnO 2 /NiO and Sn nanoparticles are produced using a scalable technique, Forcespinning (FS), and subsequent thermal treatment (carbonization). The Sn/C composite nanofibers were porous and flexible, while the SnO 2 /NiO composite nanofibers had “hairy-like” particles and pores on the fiber strands. The nanofiber preparation process involved the FS of Sn/PAN and SnO 2 /NiO/PAN solution precursors into nanofibers and subsequent stabilization in air at 280 ° C and calcination at 800 °C under an inert atmosphere. The flexible composite nanofibers were directly used as working electrodes in lithium-ion batteries without a current collector, conducting additives, or binder. The electrochemical performance of the SnO 2 /NiO/C and Sn/C composite fiber anodes showed a comparable cycle performance of about 675 mAhg −1 after 100 cycles. However, the SnO 2 /NiO/C electrode exhibited a better rate performance than the Sn/C composite anode and was able to recover its capacity after charging with a higher current density. A postmortem analysis of the composite nanofiber electrode after the aging process revealed a heavily passivated electrode from the electrolyte decomposition by-products. The synthesis and processing methods used to produce these composite nanofibers clearly were a factor for the high rate capability and excellent cycle performance of these binary composite electrodes, largely on the account of the unique structure and properties of the composite nanofibers.

With nanofibers receiving much attention in the application of lithium ion batteries (LIBs), we herein report the use of multichannel hollow nanofibers composed of TiO 2 and Carbon as a binder-free anode for LIBs. The nanofibers were produced by the Forcespinning ® of an emulsion precursor solution composed of Polyvinylpyrrolidone (PVP), Titanium (IV) butoxide, ethanol, acetic acid, and mineral oil. The as-prepared precursor nanofibers were subjected to a thermal treatment by first stabilizing in air at 280 °C followed by carbonizing at 550 °C under an argon atmosphere to form TiO 2 /C composite multichannel hollow nanofibers without the need for a sacrificial polymer to produce this morphology. This fibers’ hollow structure resulted in improved electrochemical performance when compared to non-hollow fibers. These hollow fibers also showed excellent cycling performance with a specific capacity of 228.9 mAhg −1 at a current density of 100 mAg −1 while maintaining a Coulombic efficiency of ∼98% after 100 cycles compared to the TiO 2 /C non-hollow fibers which showed a capacity of 61.4 mAhg −1 . These composite hollow nanofibers show a great promise as alternative anode materials for next generation LIBs.

Composites made of silicon nanostructures in carbon matrixes are promising materials for anodes in Li ion batteries given the synergistic storage capacity of silicon combined with the chemical stability and electrical conductivity of carbonaceous materials. This work presents the development of Si/C composite fine fiber mats produced by carbonization of poly(vinyl alcohol) (PVA)/Si composites. PVA has a high carbon content (ca. 54.5%) and, being water-soluble, it promotes the development of environmentally friendly materials. Si nanoparticles were dispersed in PVA solutions and transformed into fine fibers using a centrifugal spinning technique given its potential for large scale production. The Si/PVA fibers mats were then subjected to dehydration by exposing them to sulfuric acid vapor. The dehydration improved the thermal and chemical stability of the PVA matrix, allowing further carbonization at 800 °C. The resulting Si/C composite fibers produced binder-free anodes for lithium ion batteries that delivered specific discharge and charge capacities of 952 mA h g

In this paper, a scalable technique, Forcespinning (FS) is employed to produce SnO2/carbon composite microfibers as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SBIs). The fiber preparation process involved the FS of Tin (II) 2-ethylhexanoate/PAN and PAN solution precursors into fibers and subsequently stabilizing in air at 280oC and calcined at 800oC under an inert atmosphere. A hollow and pore microstructure of the SnO2/CFs were produced that were flexible and were directly used as free-standing anodes in LIBs and SBIs An improved electrochemical performance was observed in the SnO2/C composite electrode in particular for the sodium ion battery (SIB), with a recorded specific capacity of 198 mAhg-1 after 50 cycles at a current density of 100 mAg-1. The FS method clearly produced both carbon and SnO2/C composite fiber electrodes that showed improved electrochemical performance for the SIB due largely to the unique structure and properties of the microfibers.

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA h g− 1 at a current density of 100 mA g− 1 for over 50 cycles compared to most nanofiber electrodes prepared by electrospinning and centrifugal spinning. The FS method clearly produces Sn/C nanofiber composite electrodes that have a high specific capacity and excellent cyclic performance, owing to the unique structure and properties of the nanofibers. The FS technology is thus a viable method for the large scale production of nano/micro fibers for battery electrodes, separators, and other applications. To the best of our knowledge, this is the first time to report results on the use of Forcespinning technology to produce composite nanofiber anodes for lithium-ion batteries.

TiO2/carbon composite-fiber anodes for lithium ion batteries were prepared through the centrifugal spinning of TiS2/polyacrylonitrile (PAN) precursor fibers and subsequent thermal treatment. The TiS2/PAN precursor solutions were prepared by mixing TiS2 nanoparticles (a 2-D layered structure) with PAN in N, N-dimethylformamide (DMF). The thermal treatment of the TiS2 in the centrifugally spun PAN fibers resulted in TiO2/carbon composite fibers. The structure of TiO2 nanoparticles embedded in the carbon-fiber matrix synthesized from the TiS2 starting material may accommodate high amounts of Li ions. The TiO2/C structure may lead to increased specific capacity, improved stability, and enhanced electrochemical performance of the TiO2/C composite electrode after prolonged charge/discharge cycles. The TiO2/C composite-fiber anode delivered discharge and charge capacities at the first cycle of 683 mAhg−1 and 356 mAhg−1, respectively, with a reversible charge capacity of 290 mAhg−1 after 100 cycles at a current density of 100 mAg−1. The TiO2/C composite fibers showed an improvement in the rate performance at higher current densities compared to the graphite anode alone.

In the present study, catalytic systems based on La-doping were developed to improve the activity and performance of CoMoS2 hydrodesulfurization catalysts. Lanthanum-doped at 5, 10, or 25% of the Co content in CoMoS2 hydrodesulfurization catalysts were synthesized through a solvothermal process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the catalysts were triphasic consisting of Co9S8, MoS2, and La2S3. The La doped catalysts showed enhanced catalytic activity compared with CoMoS2 synthesized under the same conditions. The CoMoS2 prepared under solvothermal synthesis conditions showed a catalytic activity of 6.80 mol g-1 s-1, however, the La0.05Co0.95MoS2 doping showed a catalytic activity of 6.51 mol g -1 s-1 whereas the La0.1Co0.9MoS2 and La0.25Co0.75MoS2 samples showed catalytic activities of 10.7 mol g-1 s-1. The reaction products indicated the major reaction pathway was direct desulfurization. The La0.25Co0.75MoS2 catalyst after one reaction cycle showed a lower amount of carbon, than the undoped CoMoS2 catalyst.

The photocatalytic degradation of simazine (SIM) was investigated using zinc oxide/graphene oxide (ZnO/GO) composite materials under visible light irradiation. The reaction kinetics was studied to optimize the reaction parameters for efficient degradation of SIM. Batch studies were performed to investigate the effects of initial reaction pH, the loading of the ZnO onto GO, and mass of catalyst on the removal of SIM from aqueous solution. A pH of 2 was determined to be the optimal reaction pH for the different ZnO-loaded GO catalysts. In addition, a mass of 40 mg of catalyst in the reaction was observed to be the most effective for the catalysts synthesized using 20 and 30 mmol of Zn2+ ions; whereas a mass of 10 mg was most effective for the ZnO/GO composite material synthesized using 10 mmol Zn2+ ions. The reaction was observed to follow a second-order kinetics for the degradation process. Furthermore, the synthesized ZnO/GO composite catalysts resulted in higher reaction rates than those observed for pure ZnO. The 30 mmol ZnO/GO composite expressed a rate of SIM degradation ten times greater than the rate observed for pure ZnO, and sixty-two times greater than the rate of photolysis. In addition, the catalyst cycling exhibited a constant photocatalytic activity for the ZnO/GO composite over three reaction cycles without the need of a conditioning cycle.

We present results of centrifugally spun carbon fibers (CFs) made from aqueous Polyvinylpyrrolidone (PVP) solution. In the production of these fibers, the centrifugal spinning technique was used due to its high production rate of fibers. Subsequent heat treatment was conducted using a novel three step process that resulted in reduced residual stresses in the fibers after the centrifugal spinning process and subsequent thermal treatment. Moreover, this process increases the fibers’ resistance to degradation during carbonization at higher temperatures. Electrochemical performance tests were conducted on Li-ion half cells using the CFs as binder-free anodes. The carbon-fiber anode delivered a discharge capacity of Capacities of 618.7, 222.7 and 214.5 mAh g-1 at the 1st, 50th, and 100th cycles at a current density of 100 mAg-1. This work provides a novel and feasible pathway for designing and developing carbon fibers from water soluble polymer solution for use as anodes in high-performance lithium ion and sodium-ion batteries.

In this study, polyacrylonitrile (PAN) nanofibers are produced through a novel technique known as Hybrid-Spinning (HS) and used as a precursor for anodes in lithium ion batteries (LIBs). HS is a combination of two fiber-producing technologies: Centrifugal spinning (CS) and Electrospinning (ES). The use of HS for nanofiber production is promising due the limitations of both CS and ES. CS produces a high yield of nanofibers through centrifugal forces but is unable to account for the control of the fiber morphology, which limits the potential of the nanofibers-production through this technology. ES, on the other hand, produces nanofibers through electrical forces, allowing for a high degree of fiber morphology control by alternating the electrical field and process parameters. However, the high cost, safety concerns, and low yield of ES makes it unsuitable for the mass production of nanofibers in industry. Therefore, Hybrid Spinning has a high potential in changing the nanofiber industry by removing the limitations of both ES and FS while also minimizing safety-concerns, cost, and environmental impact. This work documents the morphology and characteristics of PAN nanofibers produced through HS and compares them to nanofibers made through FS and ES. The PAN fibrous mats obtained by HS are then converted into carbon nanofibers by calcination and directly used as free-binder anodes in lithium-ion batteries. The electrochemical performance of the HS carbon-fiber anodes is then compared with that prepared by ES and CS to determine the viability of HS technology with respect to Lithium-ion battery applications.

The quest to increase the energy density and improve the cycle life performance of lithium ion batteries (LIBs) and beyond has led to the development of various suitable and alternative materials for energy storage and conversion. The morphology and electrode architecture in advanced battery materials have been re-designed into nanofibers and composite nanofibers. Nanofiber-based separators and electrodes have demonstrated to improve the energy density and cycling performance of LIBs. The improvement in the structure and morphology of nanofibers in LIBs such as LiSi and LiSn, have once again ignited the interest in these Li:M alloy anodes as alternative anode and cathode materials. The major challenges that confront this new frontier have the lack of scalable method among the various techniques and designing nanofibers with good structure and morphology that could prevent dendrite penetrations. However, there seems to be a solution in sight with the advent of mass production techniques such as electrospinning and Forcespinning® that have recently been developed. In this paper, the use of nanofibers and composite nanofibers as electrode and separator materials for lithium ion, Li-O2 and Li-S batteries is reviewed. The discussion focuses on the performance characteristics of these nanostructured electrode and separator materials and methods used to improve their performances.

In this study, fibrous cellulose membranes were successfully mass produced by forcespinning® cellulose acetate, followed by alkaline hydrolysis treatment. Its performance as lithium-ion battery separator was evaluated. The cellulose membrane exhibits a randomly-oriented, fully-interconnected and highly porous three-dimensional fibrous network structure with a high porosity of 76 %. The developed membranes show good electrolyte wettability and high electrolyte uptake capability. Differential scanning calorimetry and thermal treatment show a superior thermal stability of the cellulose nonwoven membrane. Compared to commercially available polypropylene based separators, the developed fibrous cellulose membrane displays higher ionic conductivity, lower interfacial resistance and better electrochemical stability. Given its outstanding thermal characteristics and excellent electrochemical performance, this fibrous cellulose membrane has potential to be used as high-performance lithium-ion battery separator. This study provides a novel and feasible pathway for developing promising separators for high-performance lithium ion batteries.

Nanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVDF nanofiber coatings on polyolefin microporous membrane separators to improve their electrolyte uptake and electrochemical performance. The nanofiber-coated membrane separators show better electrolyte uptake and ionic conductivity than that for the uncoated membranes. In the second method, Forcespinning® (FS) was used to fabricate fibrous cellulose membranes as separators for LIBs. The cellulose fibrous membranes were made by the Forcespinning® of a cellulose acetate solution precursor followed by a subsequent alkaline hydrolysis treatment. The results show that the fibrous cellulose membrane-based separator exhibits high electrolyte uptake and good electrolyte/electrode wettability and therefore can be a good candidate for high performance and high safety LIB separators.

In the present study, titanium (IV) sulfide (TiS(2)) was synthesized and investigated for the removal of Cu(2+) and Pb(2+) ions from aqueous solutions. TiS(2) nanoparticles synthesized through a solvothermal synthesis were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle size for the TiS(2) material was determined to be 8.03 ± 0.98 nm from the diffraction pattern. Studies were performed to examine the effects of pH, temperature, time, and interfering ions on the binding of Cu(2+) and Pb(2+) to the TiS(2). As well isotherm studies were performed to determine the binding capacity of TiS(2) for both Cu(2+) and Pb(2+) ions. The pH profile studies showed optimal binding occurred at pH 2 for the sorption of both Cu(2+) and Pb(2+) to the TiS(2). The isotherm studies showed the adsorption capacities at temperatures of 4, 22, and 45°C for Cu(2+) were 243, 222, and 153 mg/g, respectively. An opposite trend in the adsorption was observed for Pb(2+) binding to the TiS(2). The observed binding capacities for Pb(2+) were 32, 166, and 357 mg/g, at temperatures of 4, 22, and 45°C, respectively. The thermodynamic parameters for binding showed a non-spontaneous process for the sorption of Cu(2+) whereas a spontaneous binding process was observed for the sorption of Pb(2+). Additionally, the binding of Cu(2+) on TiS(2) in the presence of interfering ions (Na(+), K(+), Mg(2+), and/or Ca(2+)) was observed to decrease at high concentrations; however, the binding of Pb(2+) was unaffected by the presence of the same cations.