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Living free radical dispersion polymerization of styrene in the presence of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and 2,2-azobisisobutyronitrile (AIBN) was conducted in various glycol media having different solubility parameters. Genuine heterogeneous polymerization nature was observed from the initial stage of the reaction. The solubility parameter of the media was found to significantly influence the living characteristics of the polymerization including the polymerization kinetics and the molecular weight evolution at a fixed concentration of TEMPO. A grafting of stabilizer molecules onto monomer and a possible partitioning of TEMPO between the continuous medium and particle phase were postulated for the deviation of the experimentally obtained molecular weight from the calculated value. For a poor medium for styrene, such as diethylene glycol, the living nature was achieved by increasing the amount of TEMPO. The polystyrene (PS) microsphere was well obtained in all tested glycol media and the average size was increased with enhanced affinity of the media to styrene and with decreasing concentration of TEMPO. [Copyright &y& Elsevier]

In this study, an addition–fragmentation chain transfer agent bearing dithioester group is synthesized and applied to conventional dispersion photopolymerization of styrene in ethanol medium in the presence of poly(N-vinylpyrrolidone) stabilizer with varying amounts of the RAFT agent and optionally with conventional initiator, azobisisobutyronitril (AIBN) at various temperatures. Monomer conversion, molecular weight evolution, polydispersity index (PDI), and final particle sizes are measured. The PDI of the formed polymer is between 1.5 and 2.5 in the presence of RAFT agent. Higher concentration of RAFT agent or elevated temperature leads to the acceleration of the polymerization rate resulting in fast conversion, and reducing molecular weight and PDI. Stable polystyrene beads above 1 μm in diameter are successfully prepared by means of RAFT method applied in dispersion polymerization. The weight average particle sizes are between 1.08 and 2.04 μm, and the uniformity (Dw/Dn) is ranged from 1.26 to 2.51. [Copyright &y& Elsevier]

Herein, Ni-doped Mn 2 O 3 microspheres are successfully synthesized via the facile coprecipitation of metal ions and ammonium bicarbonates, followed by a heat treatment process. Ni-doped Mn 2 O 3 exhibits outstanding catalytic performance toward the oxygen reduction reaction (ORR) in alkaline media with a half-wave potential of 0.801 V, limiting current density of 6.02 mA cm−2 at 0.6 V vs. RHE, outstanding long-term durability, and strong tolerance to methanol. Furthermore, a Zn–air primary battery using Ni-doped Mn 2 O 3 as an air cathode shows high open-circuit voltage of 1.52 V and high power density of 88.2 mW cm−2, outperforming the commercial Pt/C cathode. The exceptional performance of the Ni-doped Mn 2 O 3 microspheres is ascribed to the hierarchical structure, optimized particle size, and Ni incorporation into Mn 2 O 3. The proposed synthesis strategy provides a new methodology for the design and fabrication of electrochemically active transition metal-doped materials as efficient electrocatalysts for a variety of energy storage and conversion reactions. [Display omitted] • Ni-doped Mn 2 O 3 are fabricated via a simple co-precipitation and annealing process. • Ni-doped Mn 2 O 3 shows outstanding activity and long-term durability toward ORR. • Zn-air primary battery using Ni-doped Mn 2 O 3 possess excellent performance. [ABSTRACT FROM AUTHOR]

A back-biting reaction in fluorosilicone synthesis can compromise its precision–manufactured mechanical properties and deteriorate its molecular properties. This phenomenon can potentially disrupt the intricate structure of fluorosilicone, diminishing its durability and altering its properties over time. Cyclosiloxane with methyl and vinyl groups was added to overcome the limited properties of poly[methyl(trifluoropropyl)siloxane] and conventional rubber for harnessing versatile materials, such as vehicles and spacecraft. In this study, dimethyl carbonate, diethyl carbonate, and allyl methyl carbonate were used as promoters to suppress back-biting reactions, and an improved fluoro-vinyl-methyl silicone (FVMQ) was synthesized. 29Si nuclear magnetic resonance (NMR) spectroscopy showed that the cyclic by-products from the back-biting reaction were inhibited by adding carbonate materials. Moreover, the conversion of 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)cyclotrisiloxane also increased as the amount of promoter increased. The roles of varying carbonate promoters in altering the properties of FVMQs were studied using 1H NMR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. Furthermore, the intermediate of FVMQs was prepared and analyzed using Fourier transform infrared spectroscopy, 1H NMR spectroscopy, and gel permeation chromatography to determine the mechanism of suppressing back-biting. The results showed that controlled synthesis of FVMQs by inhibiting the production of cyclic by-products with promoters will improve silicone polymer synthesis and the vehicle industry requiring high yields of fluorosilicone copolymers. [Display omitted] • A novel FVMQs was synthesized using two materials: Ammonium-based initiators and promoters. • The addition of promoters surprisingly enhanced the molecular properties of FVMQs and suppressed cyclic by-products. • The kinetics of all FMVQs were calculated through 29Si NMR. [ABSTRACT FROM AUTHOR]

Abstract: PEDOT:PSS/MWCNTsand PEDOT:PSS/PVP nanofibers were successfully fabricated by electrospinning in order to use as a chemiresistor for detecting the aromatic volatile organic compounds (VOCs) for the first time. The response magnitudes and the cyclic tests of electrospun PEDOT:PSS/MWCNTsand PEDOT:PSS/PVP nanofibers to benzene, toluene, and o-xylene vapors were investigated. It was found that electrospun PEDOT:PSS/MWCNTsnanofibers showed much enhanced response magnitude than that of electrospun PEDOT:PSS/PVP nanofibers to benzene, toluene, and o-xylene, respectively. Also, electrospun PEDOT:PSS/MWCNTsand PEDOT:PSS/PVP nanofibers displayed reversible and reproducible responses to benzene vapor at room temperature. [Copyright &y& Elsevier]

Abstract: In this study, pool boiling heat transfer coefficients (HTCs) and critical heat fluxes (CHFs) are measured on a smooth square flat copper heater in a pool of pure water with and without carbon nanotubes (CNTs) dispersed at 60°C. Tested aqueous nanofluids are prepared using multi-walled CNTs whose volume concentrations are 0.0001%, 0.001%, 0.01%, and 0.05%. For the dispersion of CNTs, polyvinyl pyrrolidone polymer is used in distilled water. Pool boiling HTCs are taken from 10kW/m2 to critical heat flux for all tested fluids. Test results show that the pool boiling HTCs of the aqueous solutions with CNTs are lower than those of pure water in the entire nucleate boiling regime. On the other hand, critical heat flux of the aqueous solution is enhanced greatly showing up to 200% increase at the CNT concentration of 0.001% as compared to that of pure water. This is related to the change in surface characteristics by the deposition of CNTs. This deposition makes a thin CNT layer on the surface and the active nucleation sites of the surface are decreased due to this layer. The thin CNT layer acts as the thermal resistance and also decreases the bubble generation rate resulting in a decrease in pool boiling HTCs. The same layer, however, decreases the contact angle on the test surface and extends the nucleate boiling regime to very high heat fluxes and reduces the formation of large vapor canopy at near CHF. Thus, a significant increase in CHF results in. [Copyright &y& Elsevier]

Abstract: In this study, an addition–fragmentation chain transfer agent bearing carboxylic acid, 4-toluic acid dithiobenzoate (TADB), was used to synthesize carboxylic acid functionalized PS nanospheres via the miniemulsion polymerization. In addition, non-functionalized RAFT agent, benzyl dithiobenzoate (BDB), was also used to compare the surface properties of the PS nanoparticles. For the TADB system, the rate of polymerization was approximately two-fold faster than the BDB system, while the molecular weights and PDI of PS remain intact. With increasing the molar ratio of [TADB]/[AIBN] from 0 to 3.0, the average particle diameter is substantially increased from 90 to 126nm. The absolute value of zeta potential and conductivity also correspondingly increase from 49.1mV and 3.47mS/cm to 53.9mV and 4.21mS/cm, respectively. The results indicate that the surface of PS nanospheres could be functionalized by means of a carboxylic acid group on the RAFT agent and the stability of the PS miniemulsion latex could be significantly improved. [Copyright &y& Elsevier]

Herein, strongly coupled Ni 3 S 2 /MoS 2 hollow spheres derived from NiMo-based bimetal-organic frameworks are successfully synthesized for overall water splitting via a one-pot solvothermal method followed by sulfurization. A well-defined hollow spherical structure with a heterointerface between Ni 3 S 2 and MoS 2 is constructed using solvothermal and sulfurization processes. Owing to their bimetallic heterostructure, porous hollow carbon structure with large surface area, and numerous exposed active sites, the Ni 3 S 2 /MoS 2 hollow spheres are found to be efficient electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The heterostructured Ni 3 S 2 /MoS 2 hollow spheres show small overpotentials of 303 and 166 mV to reach a current density of 10 mA cm−2 for the OER and HER in 1.0 M KOH, respectively. Furthermore, an overall water-splitting electrolyzer consisting of the Ni 3 S 2 /MoS 2 hollow spheres as both the anode and cathode requires a very low cell voltage of 1.62 V to drive a current density of 10 mA cm−2 with outstanding long-term stability for 100 h. Our findings offer a new pathway for the design and synthesis of electrochemically advanced bifunctional catalysts for various energy storage and conversion applications. [Display omitted] • Ni 3 S 2 /MoS 2 was synthesized using a one-pot solvothermal method followed by sulfurization. • The synergistic effect of binary metal and unique structure led to excellent OER and HER activity. • Ni 3 S 2 /MoS 2 hollow spheres indicated outstanding catalytic activities and stability. [ABSTRACT FROM AUTHOR]

Herein, a strongly coupled Cu 3 P/FeP heterostructure with P-doped carbon derived from MIL-101 was synthesized via a three-step method involving solvothermal, carbonization, and phosphidation processes. The Cu 3 P/FeP heterostructure serves as a good catalyst because it possesses abundant interfaces between Cu 3 P and FeP, which enables the exposure of electrocatalytically active sites and tuning of surface electronic configurations. Additionally, the presence of strong heterointerfaces between Cu 3 P and FeP, and the integration of the P-doped carbon guarantee the high electrical conductivity of the catalyst. Benefiting from these advantages, the Cu 3 P/FeP electrode exhibited outstanding electrocatalytic activity toward the oxygen evolution reaction (OER), which presents a low overpotential of 315 mV to drive a current density of 10 mA cm−2 in 1.0 M KOH, thus outperforming that of the state-of-the-art RuO 2. In addition, the Cu 3 P/FeP hybrid composite exhibited long-term stability for 50 h. This work provides a new strategy for the design and preparation of transition-metal-based heterostructures and facilitates the development of high-performance energy-related materials. [Display omitted] • Cu 3 P/FeP on P-doped carbon was synthesized through a solvothermal process followed by a phosphidation treatment. • Abundant heterointerfaces led to a notable enhancement of catalytic activity toward the OER. • Cu 3 P/FeP exhibited a low overpotential of 315 mV at 10 mA cm−2 and long-term durability over 50 h. [ABSTRACT FROM AUTHOR]

Transition metal-based heterostructure materials are considered as promising alternatives to state-of-the-art noble metal-based catalysts toward the oxygen evolution reaction (OER). Herein, for the first time, a simple interface engineering strategy is presented to synthesize efficient electrocatalysts based on a novel CoFe 2 O 4 /β-Ni(OH) 2 heterogeneous structure for the electrochemical OER. Remarkably, the optimized CoFe 2 O 4 /β-Ni(OH) 2 electrocatalyst, benefiting from its hierarchical hexagonal heterostructure with strong electronic interaction, enhanced intrinsic activity, and electrochemically active sites, exhibits outstanding OER electrocatalytic performance with a low overpotential of 278 mV to reach a current density of 10 mA cm−2, a small Tafel slope of 67 mV dec−1, and long-standing durability for 30 h. Its exceptional OER performance makes the CoFe 2 O 4 /β-Ni(OH) 2 heterostructure a prospective candidate for water oxidation in alkaline solution. The proposed interface engineering provides new insights into the fabrication of high-performance electrocatalysts for energy-related applications. [Display omitted] • CoFe 2 O 4 /β-Ni(OH) 2 was synthesized by a simple interface engineering strategy. • The unique architecture with heterointerface led to outstanding OER performance. • CoFe 2 O 4 /β-Ni(OH) 2 indicated a low overpotential and long-term durability. [ABSTRACT FROM AUTHOR]

Fibrillated celluloses have gained significant attention due to their exceptional mechanical properties and eco-friendly characteristics, which make them suitable for various applications. In this study, we designed a precise approach for producing highly fibrillated microcrystalline cellulose (MCC) via ball-milling treatment using four typical silane coupling agents. The empirical data demonstrate that the fibrillization of MCC and the properties of fibrillated MCC are largely affected by the size and geometry of the functional groups of the silanes. After ball-milling, most MCC displayed enhanced e-beam tolerance and thermal stability, whereas the silane loading amount, surface area, and morphology of fibrillated MCC appeared to be random, which was exemplified by the proportional and non-proportional relationship between the loading amount and surface area of methyl silane- and phenyl silane-treated MCC, respectively. Density functional theory calculations and molecular dynamics simulations were employed to obtain the intricate details. The simulation results were in agreement with the experimental results. Finally, fibrillated MCC was incorporated into silicone foams as an additive. The thermal stability of fibrillated MCC with added silicone was greatly improved, and the tensile strength of fibrillated MCC-containing silicone foam was 44.1 and 5.4 times higher than that of the neat and MCC-containing silicone foams, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Spinel-type nickel cobaltite with numerous oxygen vacancies is successfully synthesized by hydrothermal and thermal reduction using hydrogen. The effects of oxygen vacancies on the electrochemical activity and stability for the oxygen reduction reaction are investigated. The prepared catalyst displays significantly enhanced oxygen reduction reaction (ORR) catalytic performance under alkaline conditions, which is comparable to that of commercial Pt/C. The oxygen-deficient NiCo 2 O 4 exhibits a very high limiting current density of −5.44 mA cm−2 with onset and half-wave potentials of 0.93 and 0.78 V versus the reversible hydrogen electrode (RHE), respectively. Additionally, it shows excellent durability and resistance to methanol. The enhanced ORR activity and stability of the catalyst can be ascribed to the synergistic effects of the relatively large electrochemical surface area, more exposed active sites, and good electrical conductivity derived from abundant oxygen vacancies. Image 1 • NiCo 2 O 4 nanoparticles with oxygen vacancies were synthesized by a hydrothermal method followed by mild H 2 reduction. • The H 2 -treated NiCo 2 O 4 exhibited a low overpotential and substantial long-term stability for oxygen reduction reaction. • This outstanding ORR performance and stability can be attributed to the improved physicochemical properties by H 2 treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polystyrene-fortified silica aerogel monoliths were fabricated for the first time. • The relationship between the π–π interaction and mechanical properties of aerogels was elucidated. • Aerogel containing 15 mol% phenyl groups exhibited six-times higher elastic modulus than those without the phenyl groups (from 4.86 to 29.35 MPa) while maintaining superinsulating performance (19.4 mW m−1K−1). The development of aerogel as thermally-insulating materials has been a challenge due to the intrinsic brittleness of aerogels despite of extremely low thermal conductivity. In this study, we present a novel strategy for enhancing the mechanical properties of aerogels by incorporating styrene through copolymerization with vinyldimethoxymethylsilane (VMDMS). The resulting polystyrene-containing aerogels exhibit significantly higher elastic moduli (29.35 MPa) compared to aerogels without polystyrene (4.86 MPa), while maintaining a low thermal conductivity (19.4 mW m–1 K−1). The use of polystyrene introduces π-π interactions and additional van der Waals forces, leading to a more robust material by inducing morphological change during sol–gel process. This study demonstrates the potential of fabricating polymer-silica hybrid aerogels with improved mechanical properties and thermal insulation through simple copolymerization. Our findings have implications for the development of construction materials with improved efficiency and productivity, and our paper contributes to the field of materials science and its application in various fields demanding high insulating properties. [ABSTRACT FROM AUTHOR]

In this paper, Ti/SnO 2 -Sb electrodes with different Sb dopant amounts were successfully fabricated on acid-treated Ti substrates by a thermal decomposition method; this was done in an attempt to examine the effect of the doping amount on the electrochemical activity and stability of the electrode. The physicochemical properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The electrochemical properties were investigated by linear sweep voltammetry (LSV), and the stability was studied via accelerated lifetime testing. The electro-catalytic activity of the prepared Ti/SnO 2 -Sb electrodes was strongly dependent on the amount of the Sb dopant, leading to a change in the OER overpotential. Among the prepared samples, the Ti/SnO 2 electrode with 10% of a Sb dopant showed the highest catalytic activity for oxygen evolution reaction (OER), and 87% of COD removal with 20 mA cm −2 of current density for 60 min was achieved in the presence of 10.0 g L −1 of chloride. The findings reported herein suggest that the Ti/SnO 2 electrode with an optimized Sb dopant amount shows enhanced electro-catalytic performance by easily generating active hydroxyl radicals, which act as strong oxidizing agents. [ABSTRACT FROM AUTHOR]

A series of highly microporous carbon materials was produced by carbonization of a triazine-based covalent organic polymer (TCOP) followed by carbonization and CO 2 physical activation. The N-containing porous COP was prepared from easily available economic monomer precursors via a simple Friedel-Crafts reaction, which produced a predominantly microporous structure with a high surface area. Carbonization at 600–900 °C produced predominantly microporous carbons with a narrow pore size distribution in the range of 0.5–1.5 nm. Upon further activation using CO 2 , more micropores were formed, accompanied by an increase in the surface area (to 2003 m 2  g −1 ) and the nitrogen level in the carbon structure was maintained at ca. 2 wt%. The electrochemical properties of the samples were measured by employing a three-electrode system with 6 M KOH electrolyte. Among the prepared carbon samples, the electrode fabricated using the carbon activated at 900 °C (AC-900) had a specific capacitance of 278 F g −1 at a current density of 1 A g −1 , which is significantly higher than that of a commercial activated carbon (130 F g −1 ) and ranks among the highest reported so far. This improved performance was attributed to the highly microporous structure of the nitrogen-doped carbon with a narrow pore size distribution. [ABSTRACT FROM AUTHOR]

Two different heteroatom-doped microporous carbon materials, c-CBAP-N (nitrogen-doped) and c-CBAP-NS (nitrogen/sulfur co-doped), were prepared using a carbonyl-based aromatic porous polymer (CBAP) after amine-functionalization or chemical impregnation, followed by carbonization at 800 °C. The surface areas of c-CBAP-N and c-CBAP-NS were 1060 m 2  g −1 and 1047 m 2  g −1 , respectively, which are predominantly microporous with a uniform pore size distribution centered at 0.4 nm. Their electrochemical performances as supercapacitors were measured by a three-electrode system using a 6 M KOH solution as the electrolyte. The specific capacitances of the c-CBAP-N and c-CBAP-NS electrodes were 203.2 F g −1 and 157.7 F g −1 , respectively, as measured by galvanostatic discharge–charge analysis at a current density of 1 A g −1 . Notably, these values are significantly higher than that of commercial activated carbon (130 F g −1 at 1 A g −1 ). [ABSTRACT FROM AUTHOR]

Amphiphile-assisted silica@graphite with a surface resistivity of 10 12  Ω·sq −1 was prepared via a one-step process using either an Ostwald ripening agent (Triton-X) or a bridgemer (PEG) under mild conditions. The composites containing coated fillers showed advantages in terms of their thermal and electrical properties over those using mixture of fillers. The filler possessing optimal size of graphite was incorporated with various polymer matrices such as TPEE, PDMS, epoxy, or HDPE, all of which have different processing characteristics due to their inherent viscosities. Consequently, the silica@graphite incorporated composites were found to have a superior effect on thermal and electrical properties including conductivity, dissipation, stability, and resistivity than boron nitride or alumina filled composites with the conservation of the electrical insulating property above 10 10  Ω·sq −1 for a filler loading of 0–30 vol%. [ABSTRACT FROM AUTHOR]

In rechargeable lithium-oxygen (Li-O 2 ) batteries, the porosity of porous carbon materials plays a crucial role in the electrochemical performance serving as oxygen diffusion path and Li ion transfer passage. However, the influence of optimization of porous carbon as an air electrode on cell electrochemical performance remains unclear. To understand the role of carbon porosity in Li-O 2 batteries, carbon materials featuring controlled pore sizes and porosity, including C-800 (nearly 96% microporous) and AC-950 (55:45 micro/meso porosity), are designed and synthesized by carbonization using a triazine-based covalent organic polymer (TCOP). We find that the microporous C-800 cathode allows 120 cycles with a limited capacity of 1000 mAh g −1 , about 2 and 10 times higher than that of mixed-porosity AC-950 and mesoporous CMK-3, respectively. Meanwhile, the specific discharge capacity of the C-800 electrode at 200 mA g −1 is 6003 mAh g −1 , which is lower than that of the 8433 and 9960 mAh g −1 when using AC-950 and CMK-3, respectively. This difference in the electrochemical performance of the porous carbon cathode with different porosity causes to the generation and decomposition of Li 2 O 2 during the charge and discharge cycle, which affects oxygen diffusion and Li ion transfer. [ABSTRACT FROM AUTHOR]

Designing air-stable perovskite solar cells (PSCs) is a recent trend in low-cost photovoltaic technology. Metal oxide-based electron transporting layers (ETLs) and hole transporting layers (HTLs) have attracted tremendous attention in PSCs, because of their excellent air stability, high electron mobility, and optical transparency. Herein, we report a co-precipitation method for the synthesis of p-type nanoporous nickel oxide (np-NiOx) thin films as the HTL for inverted (p-i-n) PSCs. The best-performing p-i-n PSC having np-NiOx HTL, (FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 (herein FAPbI 3 stands for formamidinium lead iodide and MAPbBr 3 stands for methylammonium lead bromide) perovskite and phenyl-C 61 -butyric acid methyl ester (PCBM)/ZnO ETL exhibited a 19.10% (±1%) power conversion efficiency (PCE) with a current density ( J SC ) of 22.76 mA cm −2 , open circuit voltage ( V OC ) of 1.076 V and fill factor (FF) of 0.78 under 1 sun (100 mW cm −2 ). Interestingly, the developed p-i-n PSCs based on p-type NiOx and n-type ZnO could retain >80% efficiency after 160 days, which is much higher than conventional PEDOT:PSS HTL-based PSCs. Our findings provide air-stable perovskite solar cells with high efficiency. [ABSTRACT FROM AUTHOR]

Herein, 3D in-situ hollow carbon fiber/carbon nanosheet/Fe 3 C@Fe 3 O 4 (h-CNF/CNS/Fe 3 C@Fe 3 O 4 ) was constructed using ferrocene and oleic acid by a solventless one-step process that did not require additional filtering, neutralization, drying, or calcination steps. The iron-oleate chelating structure that self-assembled during annealing facilitated the fabrication of 3D in-situ h-CNF/CNS/Fe 3 C@Fe 3 O 4 by undergoing graphitization at 600 °C. This carbon shell of the 3D in-situ h-CNF/CNS/Fe 3 C@Fe 3 O 4 was derived from the two cyclopentadienyl rings in ferrocene. This hybrid material made from economically cheap oleic acid exhibited superior supercapacitive behavior: high specific capacitance of 327 F g −1 at 5 mV s −1 and 210 F g −1 at 10 mV s −1 , good rate capability of 60 F g −1 at 10 A g −1 (compared to 70 F g −1 at 1 A g −1 for pure Fe 3 O 4 ), and superior retention of 108% after 6000 cycles at 100 mV s −1 . These superior supercapacitive properties were ascribed to the 3D graphitic h-CNF/CNS for enhancing electrical conductivity and the carbonaceous shell over Fe 3 C@Fe 3 O 4 core for buffering the bulk expansion of iron-related particles. [ABSTRACT FROM AUTHOR]

A promising supercapacitor material based on chitosan-modified graphene/polyaniline (CS-G/PANI) composite has been successfully synthesized by in situ polymerization. In this work, we established an environmentally friendly approach to the synthesis of well-dispersed graphene based on the biodegradable polymer chitosan (CS) using graphene oxide (GO) as a precursor. The merit of this approach is that CS acts as a stabilizing agent for GO after reduction. The resulting material was shown to exhibit good dispersion in water, and hence, this CS-G facilitates the adsorption of aniline monomers by increasing the exposure of aniline nuclei growth sites. Under the same polyaniline (PANI) concentration, chitosan modified graphene/PANI (CS-G/PANI) nanocomposites showed higher PANI adsorption than graphene/PANI (G/PANI). The CS-G/PANI nanocomposite achieved a greater which is the highest value reported to date for starch-modified graphene subjected to in situ polymerization. The modified CS-G/PANI electrode shows a potential alternative path to achieve high capacitance by preventing graphene aggregation in a simple and cost effective method, which consequently leads to a new avenue for fabricating excellent electrochemical devices. [ABSTRACT FROM AUTHOR]

Aligned carbon nanofibers (ACNFs) were fabricated by electrospinning using a high speed of rotary collector (2000 rpm). To achieve a synergy effect of the electron double layer and redox faradaic reaction, NiCo 2 O 4 was deposited on the surface of the ACNFs using an electrodeposition method. The improved electrochemical performance of the electrodes was investigated by cyclic voltammetry, galvanostatic charge-discharge testing, and electrochemical impedance analysis. Among the prepared electrodes, which were deposited for different times (5, 10, 20, and 30 s), the sample deposited by NiCo 2 O 4 for 10 s had the highest specific capacitance (90.1 F g −1 at 5 mV s −1 ), good rate capability (64.7%), and cycle stability (85.2% after 1000 cycles). In addition, to examine the effects of the alignment and redox faradaic reaction of NiCo 2 O 4, the ACNFs covered with NiCo 2 O 4 for 10 s (NC-ACNFs) were compared with the ACNFs deposited by Co 3 O 4 (C-ACNFs) and randomly oriented carbon nanofibers covered with NiCo 2 O 4 (NC-RCNFs) . The NC-ACNFs had a 15.8% and 11.3% higher specific capacitance than that of the C-ACNFs and NC-RCNFs, respectively. These results suggested that the electrochemical properties of carbon nanofibers could be improved through the structural effects of aligned nanofibers and a redox faradaic reaction of NiCo 2 O 4 . [ABSTRACT FROM AUTHOR]

Nylon 6,6/PANI nanofibers using electrospun nylon 6,6 nanofibers as a template are synthesized by the in situ polymerization of different aniline concentrations for the preparation of all-polymer based core-sheath nanofibers with high electrochemical and mechanical properties, such as lightness and flexibility. These nylon 6,6/PANI based sheath nanofibers are used as electrode materials for supercapacitors. The electrochemical performance is examined by cyclic voltammetry (CV), galvanostatic charge/discharge tests and electrochemical impedance spectroscopy (EIS). The galvanostatic charge/discharge test reveals the highest specific capacitance of 665 F g −1 at a current density of 1 A g −1 . This electrode also shows remarkable rate charge/discharge capability and high cyclic stability (62% after 1000 cycles). In addition, the high energy density of the nylon 6,6/PANI composite electrode can reach 91 W h kg −1 at a power density of 500 W kg −1 . The superior electrochemical properties of the core-sheath nylon 6,6/PANI nanofibers are attributed to their core-sheath structure, thin wall thickness and uniform wall distribution, which can improve the performance of electroactive PANI during the charge/discharge process. The good electrochemical performances highlight the potential of the nylon 6,6/PANI electrode as an electrode material for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]