Search

Rechargeable aqueous zinc-ion batteries (ZIBs) featured with environmental friendliness, low cost, and high safety have attracted great interest but still suffer from the lack of high-performance electrodes. Herein, a facile in situ approach is developed to simultaneously introduce multivalence, increase the interlayer water content, and expand the interlayer distance in hydrated V 2 O 5. These structural modulations endow the as-obtained layer-expanded V 2 O 5 2.2H 2 O (E-VO) nanosheets with faster charge transfer kinetics, more Zn2+ storage space, and higher structural stability than precursor V 2 O 5. Besides, a unique flexible Zn/stainless steel (Zn/SS) mesh composite anode with low polarization and uniform Zn stripping/plating behavior is fabricated, which alleviates the Zn dendrite growth. As cathode for aqueous ZIBs, E-VO exhibits high reversible capacity (450 mAh g−1 at 0.1 A g−1), good rate capability (222 mAh g−1 at 10 A g−1) and long stability (72% capacity retention for 3000 cycles at 5 A g−1). Moreover, the flexibility and large lateral size make E-VO a high-performance binder-free cathode for flexible quasi-solid-state Zn/E-VO battery, i.e. high capacity under different bending states (361 mAh g−1 at 0.1 A g−1), good rate capability (115 mAh g−1 at 2 A g−1), and long stability (85% capacity retention for 300 cycles at 1 A g−1). The achievements of this study can be considered as an important step toward the development of aqueous-based ZIBs. Image 1 • Hydrated V 2 O 5 with expanded interlayers is prepared by a facile in situ approach. • Zn/stainless steel mesh composite is designed to alleviate the Zn dendrite growth. • Modified V 2 O 5 shows much improved Zn2+ storage capability than precursor V 2 O 5. • Flexible quasi-solid-state Zn-ion battery is fabricated with superb performance. [ABSTRACT FROM AUTHOR]

Today's rapid increase in lithium-ion battery (LIBs) applications exacerbates a voluminous rise of spent LIBs. Furthermore, manufacturing LIB cathode materials demands valuable metals depleting from the earth crust. Efficient routes are urgently needed to address these problems for upcycling cathode materials from spent LIBs into precursors for manufacturing new LIB cathode materials. Hydrometallurgy is a popular method for extracting metal from spent LIB cathode materials, wherein precipitation processes serve as the foundation for obtaining metal salts. However, the resulting precipitate metal salts are often inferior in yield and quality, limiting their use as precursors for resynthesizing new LIB cathode materials. This review is dedicated to untangling the individual challenges in the precipitation processes, identifying the root causes, and their effects on the quality and yield of the precursors. Based on the problem cause-effect correlation, enhancement strategies, research design guidelines, and future perspectives are highlighted to improve the precipitation processes and the precursor quality and yield for LIB cathode material resynthesis. [Display omitted] • Stoichiometry, purity, particle size & shape are key criteria for a good precursor. • Seven challenges identified for poor precursor yield or quality. • Challenges are intertwined to multiple precipitation reaction control parameters. [ABSTRACT FROM AUTHOR]

Electrospinning is a versatile and efficient technique to fabricate hollow structured nanofibers of metal oxides, carbon, metals, composites, and others, which present great potential in energy conversion and storage devices. In this review, we provide a comprehensive overview of the preparation of electrospun inorganic hollow nanofibers and their applications in advanced secondary batteries. We first describe different synthetic methodologies for fabricating hollow nanofibers as well as the compositional and geometric manipulation of these nanofibers based on electrospinning. We next go on to discuss the recent research activities involving electrospun hollow nanofibers in advanced secondary batteries, including lithium-ion batteries, sodium-batteries, Li-S batteries, and metal-air batteries. In each application, some typical examples and a critical commentary are provided to demonstrate the superior properties of the hollow structures. The correlation between geometric properties of hollow structures and their performance are also highlighted. These results demonstrate that electrospun hollow nanofibers with unique properties such as large surface area, engineered high porosity, and free-standing characteristics have a direct impact on the final performance in their applications. Finally, in conclusion, the remaining challenges of adopting electrospun hollow nanofiber materials in their future applications are further discussed. [ABSTRACT FROM AUTHOR]

As a potential alternative to the prevailing lithium ion batteries, the application of sodium (Na) ion batteries (NIBs) in renewable energy and smart grid have revitalized research interest for large-scale energy storage. One of the roadblocks hindering their future commercialization is the development of suitable anode materials. Herein, we present the large-scale preparation of highly uniform iron sulfide (Fe 1−x S) nanostructures by a cost-effective and versatile one-step sulfurization strategy. Impressively, as a high-rate and viable sodium-ion anode, the as-prepared Fe 1−x S nanostructure manifests appealing electrochemical performance (a high discharge capacity of 563 mA h g −1 over 200 cycles at a current density of 100 mA g −1 and outstanding cycling stability even at high rate of 10 A g −1 up to 2000 cycles). Moreover, the proven pseudocapacitance contribution interprets the unprecedented rate capability. Meanwhile, the sodium storage mechanism in the as-prepared samples has also been investigated by using the in-situ X-ray diffraction techniques. Remarkably, a full cell based on Na 0.6 Co 0.1 Mn 0.9 O 2 cathode and Fe 1−x S anode deliver high discharge capacity (393 mA h g −1 ) and superior cycling stability. [ABSTRACT FROM AUTHOR]

Among the various kinds of electrospun materials, electrospun carbon nanofibers (ECNFs) represent one of the most interesting research directions in nanoscience and nanotechnology, with the capability of realizing structural and functional features through tailored designs and controlled synthesis. The degree of precision in controlling the structures, morphologies, and compositions of ECNFs, together with the incorporation of other materials, allows for the creation of nanoscale building blocks with unique electronic, catalytic, and adsorption properties, thus enabling a variety of promising opportunities in the energy-related field. This review is centered on the recent major advances in the controlled synthesis of ECNFs, and the potential of the resulting hybrid composites for energy applications. The promising energy conversion applications of ECNFs and their hybrid composites, such as in solar cells and fuel cells, are also discussed. The use of ECNFs and their hybrid composites in energy storage technologies such as batteries, supercapacitors, and hydrogen storage is then reviewed. In each case, we highlight the benefits of materials with high surface area, porous structures, and the free-standing architecture of ECNFs which act to amplify the surface activity and support other materials, leading to enhanced energy conversion and storage performance. Moreover, we provide a commentary on the challenges, as well as perspectives for potential future research on ECNFs and their hybrid materials. This review provides an overall perspective on the current state of efforts aimed at the controlled synthesis of ECNF-based materials for their various potential applications, along with the challenges remaining to be addressed, giving an insight into a promising strategy to ameliorate some of the energy issues impacting the world today. [ABSTRACT FROM AUTHOR]

Design and fabrication of advanced functional materials is essential but still a challenge for current energy storage devices. Herein, polypyrrole coated highly porous vanadium oxide (V 2 O 5 @Ppy) nanorod and nanoplate arrays with large mass loadings, have been successfully constructed on carbon felt (CF) via a facile solvothermal reaction followed by in-situ polymerization technique. Interestingly, the structure of the V 2 O 5 thin films can be simply tuned from porous nanoplates to nanorods with controlled calcination time. In addition, MnO 2 nanowires with Ppy coating were also grown on the CF substrates to form MnO 2 @Ppy/CF electrode through the similar method. As integrate electrodes for energy storage devices, V 2 O 5 @Ppy/CF nanorods demonstrate more superior electrochemical properties compared to V 2 O 5 @Ppy/CF nanoplates. By virtue of their intriguing structural features and uniformly Ppy coating, a solid-state flexible hybrid device (SFHD) based on V 2 O 5 @Ppy/CF and MnO 2 @Ppy/CF as the negative and positive electrode, respectively, manifests outstanding cycling stability (approximately 89% retention even after 20,000 cycles), excellent mechanical flexibility, and remarkable energy density (28.6 W h kg −1 at power density of around 200 W kg −1 ), which makes it hold great potential to be unexceptionably flexible devices for portable and wearable electronics. [ABSTRACT FROM AUTHOR]

Quantum-dot sensitized solar cells (QDSCs), as a promising type of new generation photovoltaic devices, require an efficient and inexpensive counterelectrode (CE) for their commercial application. In this work, novel noble-metal-free Cu-doped CoS (Cu–CoS) CEs are designed for QDSCs. The hierarchical three-dimensional (3D) Cu–CoS porous nanosheet films on fluorine doped tin oxide (FTO) glass are prepared by a simple hydrothermal reaction followed by a cation exchange reaction process. As an alternative to Pt electrode, the 3D structure of porous Cu–CoS nanosheets with high reflectivity can provide a great large number of active catalytic sites and easy accessibility toward S n 2 − / S 2 − electrolyte solution, leading to high electrocatalytic activity. Theoretical calculations are further performed to demonstrate the superior catalytic activity for the Cu–CoS CE. As a result, the QDSC with an optimized Cu–CoS CE exhibits a high photovoltaic conversion efficiency of 6.1% under 100 mW cm −2 irradiation, which is much higher than that of the references Pt and bare CoS CEs. Furthermore, this QDSC device shows long-term stability, which makes it as a very promising and low cost effective material for QDSCs. [ABSTRACT FROM AUTHOR]

Rechargeable lithium–oxygen (Li–O 2 ) batteries are attracting much interest due to their highest energy density among chemical batteries. Recent studies have focused on designing highly efficient catalysts to improve the electrochemical performance of Li–O 2 batteries for long-term cycling. In this work, we report controlled synthesis of high efficient spinel catalysts in Li–O 2 batteries. The catalysts present core–shell spheres, which are constructed by porous nanoplates. The remarkable feature of the hierarchical porous structure cannot only provide many electrocatalytic sites but also facilitate the flow of oxygen and infiltration of the electrolyte, and eventually improving the capacity and cyclability. As a representative catalyst, the synergistic effects of the inherited superior catalytic activity and the unique porous structure of NiCo 2 O 4 lead to low overpotentials, high rate capacity as well as excellent long-term cyclability in Li–O 2 cells. This study affords a new strategy to achieve optimal performance in spinel catalysts, which may be extended to the preparation of other materials for a broad range of energy and environmental applications. [ABSTRACT FROM AUTHOR]

Abstract: We report the synthesis of CuO nanostructures by metal organic framework (MOF) based approach. Spherical shaped, phase pure CuO nanoparticles are obtained by controlled pyrolysis of Cu-based MOF. Electrochemical properties are evaluated in half-cell assembly and it is found that ∼1.6mol of Li (∼538mAhg–1) is cycleable via conversion reaction. Further, MOF derived CuO retained ∼90% of initial reversible capacity after 40 cycles. Rate performance studies showed the deliverable reversible capacity of ∼210mAhg–1 at high current rate of 2Ag–1. [Copyright &y& Elsevier]

Abstract: Photocatalytic degradation and mineralization of bisphenol-A (BPA) by a novel photocatalyst, nitrogen-doped TiO2 hollow sphere (NhT), under blue, green and yellow lights emitted by light emitting diodes (LEDs) were investigated. The photocatalyst was synthesized through polystyrene spheres templating and treatment with ammonia to extend its light absorption properties to 550nm (E g =2.26eV) and meanwhile possess high porosity and specific surface area. Nitrogen incorporation was confirmed through XPS analysis indicating the presence of O–Ti–N or Ti–O–N linkages in the photocatalyst material. The NhT exhibited significant increase of BPA degradation and mineralization under blue, green and yellow lights as compared to the undoped TiO2 hollow sphere, powder TiO2, and Hombikat UV100. The photocatalytic degradation of BPA increased with pH, and the rate was the highest even at pH>pKa1 of BPA (i.e., pH 9.6). At circumneutral pH, 90% of BPA was degraded in 2h under irradiation of blue light with NhT, while TOC removal was 66% after 6h of irradiation. The main aromatic intermediates formed were identified with GC/MS and LC/MS/MS as 4-hydroxyacetophenone, 4-isopropylphenol, 4-isopropenylphenol and isopropanolphenol. The pathways for BPA degradation under visible light appear to agree with those with UV/TiO2. [Copyright &y& Elsevier]

Abstract: A novel nitrogen-doped P25-TiO2 of bimodal structure with activated carbon supported (N-P25-TiO2/AC) was synthesized via the modified sol–gel techniques. Besides adding urea as N-source, the N-doping could also be induced through calcination under mixed NH3/N2 atmosphere. The composite was characterized using XRD, porosimetry, UV–vis spectrophotometry, FTIR, XPS, SEM/EDX and TEM. The physical stability of the composite was examined through ultrasonication disruption, and the composite exhibited good physical stability. The synergistic effects of the adsorption-solar photocatalysis of sulfamethazine (SMZ) as exhibited by the composites were examined. The best performing bimodal composite was N-P25-TiO2 (25+10)/AC, which comprised 25% of N-P25 and 10% N-TiO2 (sol) by weight composition (wt%). The maximum adsorption capacity (S max) for the N-P25-TiO2 (25+10)/AC, at pH 3.0, 6.0 and 10.0 was 183±3, 194±3, and 103±2mgg−1, respectively. The effects of the total loading of N-doped titania, sol–gel synthesis technique, weight distribution of N-P25 and N-TiO2 (sol), composite dosage, light wavelength spectrum and solution pH on the photocatalytic degradation (PCD) of SMZ were investigated. The N-P25-TiO2 (25+10)/AC composite exhibited enhanced PCD efficiency under solar irradiation with a pseudo first-order rate constant (k app) of 0.48h−1, as compared to other types of bimodal composites because its higher N-P25 content led to a greater photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Sol–gel method with the incorporation of two-stage calcination protocol was developed to synthesize a bi-functional composite, viz. nitrogen-doped titanium dioxide supported on activated carbon (N-TiO2/AC). Various types of N-TiO2/AC composites produced using different calcination conditions were characterized using XRD, porosimetry, XPS, SEM and TEM. All the N-TiO2/AC composites exhibited good adsorption of a hydrophobic pollutant (bisphenol-A (BPA) as model pollutant) in water. The effects of calcination conditions, light wavelength and composite dosage on photocatalytic degradation (PCD) performance were investigated. N-TiO2/AC (400M-700T) composite produced from two-stage calcination (400°C in air with subsequent 700°C in NH3/N2 atmosphere) was comprised of anatase–rutile phase and this composite exhibited significant PCD efficiency for removing BPA under simulated solar irradiation, with initial pseudo first-order rate constant of ca. 0.67h−1. In addition, the N-TiO2/AC composite exhibited satisfactory BPA removal performance over several series of reuse. Photostability of the N-TiO2/AC composite was also examined to address its durability under prolonged exposure of UV irradiation. The amount of carbon being leached in water was found to be less than 0.1% after 6h of UV irradiation. [Copyright &y& Elsevier]

Multifunctional structural batteries have gained interest in recent years due to their capability to simultaneously store electrochemical energy and bear mechanical load. The structural cathode is an integral component to form multifunctional structural batteries, and its electrochemical and mechanical performance are highly dependent on the fabrication process. Thus, this review aims to explore the fabrication techniques for these cathodes via indirect (casting, dip coating and layer-by-layer assembly, electrophoretic deposition, vacuum filtration & use of polymer matrix) and direct (synthesis) methods. Challenges and improvements in fabricating structural cathodes specific to these techniques will also be put forth, and the influence of cathode microstructure on the electrochemical and mechanical performances will also be discussed. This review also aims to introduce a performance metric using multifunctional efficiency as a basis for comparison when evaluating the multifunctional performance of structural cathodes. Future considerations on improving energy storage and load-bearing capability of structural cathodes will also be highlighted in order to develop more robust and efficient structural batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Fruit peel discards from various sources are harnessed as a renewable waste biomass feedstock for lithium-ion battery (LIB) recycling, showcasing the potential for green chemical production. Extractive methods, including hot water treatment, ultrasonic-assisted hydrolysis, and fermentation, produce a fruit peel-derived lixiviant (FL) to extract valuable metals from industrial-grade spent LIB black mass. The FL obtained through fermentation using various fruit peels (e.g. orange, mango, papaya, honeydew, lemon, and pomelo) could effectively leach more than 90% of cobalt and lithium from LCO black mass, without the need for synthetic chemicals. Additionally, the use of oxalate precipitation could recover the leached cobalt ions from orange peel-derived FL at a high yield of around 85%. The cathode material regenerated from cobalt precipitate coupled with LiOH supplementation exhibits excellent electrochemical performance with a capacity retention of 93% after 140 cycles. Overall, this proposed method of using FL-enabled LIB recycling offers a significant new opportunity for a more resource-efficient circular and sustainable economy. [Display omitted] • Fruit peel discards are upcycled as chemical feedstock for lithium-ion battery recycling. • Fermentation-based lixiviant recovers >90% of cobalt and lithium from black mass without synthetic chemicals. • High-yield cobalt recovery achieved through oxalate precipitation. • Regenerated cathode material shows excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

In the present paper, the hierarchical three-dimensional Fe 3 O 4 @porous carbon matrix (PCM) and Fe 3 O 4 @PCM/graphene are synthesized by a facile annealing of Mil-53(Fe) templates. Their electrochemical performances are evaluated as anode materials for lithium ion batteries. In comparison with Fe 3 O 4 @PCM, the Fe 3 O 4 @PCM/graphene electrode exhibits a much better cycling performance with the reversible capacity high up to 1000 mAh g −1 after 500 cycles at 1 C. The improved performance can be ascribed to the high conductivity and structure stability provided by the unique graphene based hierarchical three-dimensional nanostructure. [ABSTRACT FROM AUTHOR]

Si doping at high voltage spinel LiNi 0.5 Mn 1.5 O 4 are presented as an effective strategy to greatly increase the electrochemical performance. Well-crystallized LiNi 0.5 Mn 1.5-x Si x O 4 (x = 0.05, 0.10, 0.15, 0.20) with homogeneous Si distribution are successfully synthesized through solid-state reaction. Structural and electrochemical characteristics are investigated through FESEM, XRD, FTIR, Raman spectroscopy, cyclic voltammetry and galvanostatic charge/discharge testing. It can be demonstrated that Si doping significantly improves the electrochemical performance. LiNi 0.5 Mn 1.35 Si 0.15 O 4 exhibits reversible capacities of 123 mAh/g after the 100th cycle at 0.5C and LiNi 0.5 Mn 1.35 Si 0.15 O 4 as well as LiNi 0.5 Mn 1.3 Si 0.2 O 4 show superior electrochemical stability over the pristine LiNi 0.5 Mn 1.5 O 4 material. Since the Si-O bond exhibits high dissociation energy of 798 kJ/mol (298 K), which is far beyond of the dissociation energies of the Mn-O or Ni-O bonds, the excellent electrochemical performance might be associated with an increased structural and chemical stability caused by incorporation of Si into the Oxygen-rich crystal lattice. [ABSTRACT FROM AUTHOR]

The effect of processing history and morphology is of particular importance for lithium-ion electrolytes for achieving higher ionic conductivities. In this study, single ion conducting poly (4-lithium styrene sulfonic acid) was synthesized by neutralization reaction from polystyrene sulfonic acid, and the effect of morphology and processing method was studied by comparing pelletized, electrospun and gel samples. The PSSLi gels displayed best ionic conductivity, while the pelletized samples showed the worst ionic conductivity. Although electrospinning led to a free standing electrolyte, the lower amount of solvent phase led to lower ionic conductivity when compared to the PSSLi gel. The ionic conductivity at room temperature improved from 6.6 × 10 −5 S/cm to 1.4 × 10 −3 S/cm by optimizing the processing methodology and the lithium ion concentration. The results show that PSSLi based single ion conducting lithium (SICL) gels are a promising candidate for lithium ion battery application. [ABSTRACT FROM AUTHOR]

Two types of trigol reduced one pot synthesized graphene (TRG) based nanocomposites (SnO 2 -TRG, and Fe 3 O 4 -TRG) are examined as potential anodes for Lithium ion battery (LIB) applications. The two specific systems represent different electrode reaction mechanisms, namely alloying, and conversion respectively. The high resolution transmission electron microscopy (HR-TEM) analysis confirms the uniform distribution of SnO 2 (∼2 nm), and Fe 3 O 4 (∼8 nm) particulates on ultrathin TRG nanosheets and highlights the importance of surfactant free synthesis. The SnO 2 -TRG, and Fe 3 O 4 -TRG exhibited the maximum reversible capacity of ∼947, and ∼1024 mA h g −1 , respectively. The results show that such graphene based composite materials can be effectively used as prospective anodes for LIB applications. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries are considered a top alternative to lithium-ion batteries for large-scale renewable energy storage units due to their low cost and the abundance of sodium-bearing precursors in the earth's mineral deposits. However, the absence of a suitable negative electrode material hinders their development. In this contribution, we report the preparation of nitrogen and phosphorous co-doped carbon microspheres through a hydrothermal process followed by heat treatment in presence of (NH 4 ) 2 HPO 4 and investigate their electrochemical performance as anode in sodium-ion batteries. Benefiting from the N, P co-doping, the obtained N, P co-doped carbon microspheres demonstrates high specific capacity, excellent cycle stability as well as good rate performance. The as prepared N, P co-doped carbon microspheres can deliver a reversible capacity of 305 mAh g −1 at a current density of 0.1 A g −1 and even deliver a capacity of 136 mAh g −1 at 5 A g −1 . This superior sodium storage performance of N, P co-doped carbon makes it as a promising low-cost anode candidate for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Human hair is a cheap and easily available source of carbon to be used as high performance electrode for electrochemical energy storage devices. In the present work, human hair is pre-treated and then activated using NaOH before being employed as electrode. The resulted activated carbon (ACHH) exhibits a high specific surface area of 1116 m 2 g −1 which is one of the pre-requisite for it to be used as an electrode for supercapacitor applications. ACHH delivered a specific capacitance of ∼115 F g −1 at a current density of 100 mA g −1 in single electrode configuration with Li in the presence of organic medium. This result was followed by the fabrication of symmetric supercapacitor and delivered an energy density of 19.2 Wh kg −1 . The energy density has been further improved by introducing an insertion type electrode, Li 4 Ti 5 O 12 in Li-ion hybrid electrochemical capacitor (Li-HEC) assembly. The combined battery-supercapacitor type reactions in Li-HEC recorded the maximum energy density of 23 Wh kg −1 . An excellent cycleability is noted for both symmetric and Li-HEC in an organic medium. [ABSTRACT FROM AUTHOR]

We report facile, one step synthesis of disordered graphitic carbon by high temperature (1000 °C) pyrolysis of indanthrone dye (ID). The pyrolysed carbon is disordered in nature and the same is clearly evidenced by various analytical techniques like X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. Na-insertion properties of such indanthrone dye derived disordered graphitic carbon (IDDGC) is evaluated in half-cell assembly (Na/IDDGC). The test cell delivered a reversible capacity of ∼160 mAh g −1 at current density of 25 mA g −1 . In addition, excellent cycling profiles are noted for such IDDGC, which retains ∼67% of initial reversible capacity after 500 cycles. The present study clearly highlights the importance of disorder in the graphitic carbon for efficient Na-ion storage. [ABSTRACT FROM AUTHOR]

Abstract: The advantageous properties of both solid soft matter electrolytes and polymer gel electrolytes (PGEs) are combined to develop a electrospun polymer composite electrolyte (PCE) for lithium ion batteries, based on addition of butanedinitrile (BDN, the plastic crystal) to poly(vinylidenefluoride-co-hexafluoropropylene) {P(VdF-co-HFP)} (semi crystalline polymer). Polymer composite electrolytes are prepared by activating the fibrous membrane with 1M LiPF6 in EC/DEC. The electrochemical characterization shows that the addition of BDN significantly improves the ionic conductivity of composite electrolytes even at lower temperatures due to the active role played by BDN in ion conduction. Also the compatibility of the polymer composite electrolyte with lithium electrode improves by incorporation of BDN. Galvanostatic cycling test demonstrates the suitability of these polymer composite electrolytes for lithium ion batteries in both Li/PCE/LiFePO4 (half cell) and LTO/PCE/LiFePO4 (full cell) configurations. The addition of BDN improves the charge discharge performance and cycling stability of the polymer composite electrolytes. [Copyright &y& Elsevier]

Abstract: Composite films of platinum and polyaniline (Pt/PANI) with different Pt loadings are prepared by chemical reduction and then a spin-coating process on fluorine-doped tin oxide (FTO) substrates. The obtained Pt/PANI transparent counter electrodes are applied in quasi-solid dye-sensitized solar cells (QDSCs) from front and rear light illuminations, using electrospun poly(vinylidenefluoride-co-hexafluoropropylene)/TiO2 (PVDF-HFP/TiO2) as the electrolyte. The analytical results show that the 1.8-nm sized Pt nanoparticles are distributed uniformly in the Pt/PANI film when the Pt loading is 1.5μgcm−2. Electrocatalytic activity of the Pt/PANI electrode with 1.5μgcm−2 Pt loading for the I3 −/I− redox reaction is higher than the conventional sputtered Pt electrode. Furthermore, the mean optical transmittance of the Pt/PANI electrodes is above 60% in the wavelength of 400–800nm. The optimal QDSC composed of Pt/PANI with 1.5μgcm−2 Pt loading exhibits power conversion efficiencies of 6.34% and 3.85%, when measured using an AM1.5G solar simulator at 100mWcm−2 under front and rear light illuminations. The efficiencies are both higher than those of the QDSCs employing the conventional sputtered Pt counter electrode with 8.3μgcm−2 Pt loading. Moreover, the QDSC exhibits superior long-term stability. These promising results make the potential application of Pt/PANI films as cost-effective, transparent counter electrodes. [Copyright &y& Elsevier]

Abstract: A new approach for fabricating polymer gel electrolytes (PGEs) based on electrospun poly(vinylidenefluoride-co-hexafluoropropylene) {P(VdF-co-HFP)} incorporated with layered nanoclay has been employed to enhance the ionic conductivity and electrochemical properties of P(VdF-co-HFP) without compromising its mechanical strength. The effect of layered nanoclay on properties of membranes has been evaluated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Surface morphology of the membranes has been studied using field-emission scanning electron microscopy (FE-SEM). Polymer gel electrolytes are prepared by soaking the fibrous membrane into 1M LiPF6 in EC/DEC. The electrochemical studies show that incorporation of layered nanoclay into the polymer matrix greatly enhanced the ionic conductivity and compatibility with lithium electrodes. The charge–discharge properties and cycling performance of Li/LiFePO4 cells comprising nanocomposite polymer gel electrolytes have been evaluated at room temperature. [Copyright &y& Elsevier]

Abstract: Hybrid organic–inorganic polymer gel electrolytes (PGEs) based on polymer–clay nanocomposite microporous membrane containing 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate/diethyl carbonate (EC/DEC) are fabricated and their electrochemical characteristics in lithium ion batteries are studied. Poly(vinylidene fluoride) (PVdF)–clay nanocomposite membrane containing different clay loading are prepared by phase inversion method. Aqueous suspension of montmorrillonite (MMT) clay in dimethyl acetamide (DMAc) is used as the nano-clay. The morphology of the clay dispersion with sonication time is studied by environmental scanning electron microscope (E-SEM). The intercalation/exfoliation of polymer–clay nanocomposite is characterized by X-ray diffraction (XRD). Differential scanning calorimetry (DSC) and thermal gravimetric analysis are used for the evaluation of thermal properties. DSC analysis shows that crystallinity of nanocomposite decreases with increasing nano-clay content. The effect of clay on the membrane morphology, ionic conductivity and electrochemical properties of the PGEs in lithium ion rechargeable batteries are studied and results are compared. Incorporation of 2wt.% nano-clay in PGE enhances its ionic conductivity from 0.78 to 3.08mScm−1 at room temperature. Li-ion half cell comprising of Li/PVdF–clay(2wt.%)-PGE/LiMn2O4 delivers high charge–discharge capacity (∼120mAhg−1) and shows stable cycle performance. [Copyright &y& Elsevier]

Abstract: A photocatalytic composite, namely nitrogen-doped titanium dioxide supported on activated carbon, or N-TiO2/AC, was synthesized using the sol–gel method. This composite was characterized using X-ray diffraction (XRD), N2 adsorption–desorption isotherm, UV–vis spectrophotometry, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The titania was found to consist predominantly of anatase. The AC-supported N-TiO2 had a smaller average crystallite size (ca. 5.0nm) as compared to the unsupported N-TiO2 (ca. 5.4nm). XPS revealed that interstitial nitrogen doping occurred in N-TiO2 and N-TiO2/AC. Observations under TEM revealed that N-TiO2 nanocrystals were anchored on the surface of the AC. The dual-functionality properties of N-TiO2/AC were evaluated using bisphenol-A (BPA) as the target pollutant in the aqueous phase. The effect of pH and influence of excitation wavelengths were investigated. Inhibition of BPA adsorption occurred at pH 11.0, thus resulted in slower kinetics of BPA photodegradation. N-TiO2/AC was found to be photoresponsive under visible-light (420–630nm) illumination. [Copyright &y& Elsevier]

Herein, Taguchi L 9 orthogonal array was used for the first time to optimize synthesis of diameter-controlled multi walled carbon nanotubes (MWCNTs). The nanoadsorbents, MWCNTs 5 − 15 nm and MWCNTs 16 − 25 nm were applied for Pb(II) and Ni(II) ion removal from paint, battery and electroplating wastewater. The results indicated successful synthesis of MWCNTs with diameter distribution ranges of 5–15 nm and 16–25 nm. The synthetized smaller diameter MWCNTs 5 − 15 nm revealed higher Brunauer-Emett-Teller (BET) surface area of 1306 ± 5 m2/g compared to larger diameter MWCNTs 16 − 25 nm with the surface area of 1245 ± 4 m2/g. They demonstrated excellent adsorption of Pb(II) and Ni(II) ions within the permissible concentration proposed by WHO at pH, contact time, adsorbent dosage and temperature of 5, 60 min, 30 mg/L and 50 °C, respectively. Particularly, MWCNTs 5 − 15 nm possessed high adsorption capacity of 215.38 ± 0.03 mg/g for Pb(II) and 230.78 ± 0.01 mg/g for Ni(II). Again, the maximum adsorption capacity of 201.35 ± 0.02 and 206.40 ± 0.02 mg/g was achieved for Pb(II) and Ni(II) using MWCNTs 16 − 25 nm . All in all, the adsorption capacity of the nanoadsorbents at the investigated diameter range showed higher efficiency compared to other materials for heavy metals elimination from chemical industrial wastewater. Image 1 [ABSTRACT FROM AUTHOR]