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• This manuscript reports the first sulfonyl-containing epoxy dielectric film for energy storage application. • The fabricated polymers demonstrate a high discharge energy density up to 8.78J/cm3 with efficiency of 91.5%. • Pendant and bridging sulfonyl incorporation are found to have distinct influence on dielectric and thermal properties. Polymer based dielectric film capacitors with enhanced energy density and high temperature resistance are urgently required to replace the general used biaxially oriented polypropylene (BOPP) dielectric counterparts in power grid and electrical vehicles. This study reports the development of sulfonated flexible epoxy polymers, which demonstrate excellent properties including high dielectric constant (4.9–6.0), low dielectric loss, high charge–discharge efficiency and desirable thermal stability. The obtained epoxy film achieves an impressive efficiency of 91.5 %, accompanied by discharge energy density up to 8.78 J/cm3 at 550MV/m at room temperature, nearly twice that of BOPP. While the prepared film still possesses discharge energy density of 1.01 J/cm3 at 200MV/m, even when exposed to temperatures up to 150 °C, which is nearly twice that of PEI under same conditions. Simulation results reveal that sulfonyl groups can effectively improve dielectric performance without sacrificing heat resistance of epoxy polymers. The influence of sulfonated groups and positions are figured out by constructing epoxy film with pendant and bridging sulfonyl groups. It is concluded that the enhanced dipole moments caused by pendant sulfonyl group is preferred in improving energy density, while the increased rotational energy barrier attributed to bridging sulfonyl group is critical to the enhancement of temperature tolerance. The manipulation of sulfonation in polymer dielectrics' design introduces a deep perspective for advancing high energy storage films. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials are effective conductive fillers for permanent antistatic composites due to their long-term stability in electrical conductivity under ambient temperature and humidity. Where graphene or graphene-like materials have been demonstrated to be the most promising conductive fillers. However, the preparation of graphene and further dispersion into polymer matrices to obtain interconnected conductive networks is still a big challenge for conductive composites. A facile green path (all solid states), microsphere rolling transfer method, has been adopted to introduce nano-graphite conductive fillers for polyethylene. The nano-graphites were well dispersed into polyethylene matrices to give interconnected networks with low loading. The conductivity reinforcements of nano-graphite fillers even overtake those of complicated graphene fillers. The percolation threshold of the conductive composites with nano-graphite fillers for polyethylene has been demonstrated to be as low as 0.85 wt%. The electrical conductivity of the conductive composites was measured to increase by 13 orders of magnitude with 2.05 wt% nano-graphite fillers (0.02 S/m), much higher than traditional solid mixing methods and approaching to the best effects from complicated solution mixing of graphene fillers. The nano-graphite conductive networks are easily adjusted and the method is feasible to almost all conventional solid resins and industrial production. Image 1 [ABSTRACT FROM AUTHOR]

Dielectric materials with good thermal transport performance and desirable dielectric properties have significant potential to address the critical challenges of heat dissipation for microelectronic devices and power equipment under high electric field. This work reported the role of synergistic effect and interface on through-plane thermal conductivity and dielectric properties by intercalating the hybrid fillers of the alumina and boron nitride nanosheets (BNNs) into epoxy resin. For instance, epoxy composite with hybrid fillers at a relatively low loading shows an increase of around 3 times in through-plane thermal conductivity and maintains a close dielectric breakdown strength compared to pure epoxy. Meanwhile, the epoxy composite shows extremely low dielectric loss of 0.0024 at room temperature and 0.022 at 100 ℃ and 10−1 Hz. And covalent bonding and hydrogen-bond interaction models were presented for analyzing the thermal conductivity and dielectric properties. [ABSTRACT FROM AUTHOR]

• A novel support based on CdS quantum dots was proposed for UiO66-(SH) 2 -CdS hybrids. • CdS quantum dots were connected to the UiO-66-(SH) 2 by thiol group. • The as-prepared UiO-66-(SH) 2 -CdS0.7 showed superior photocatalytic performance for H 2 evolution. • UiO66-(SH) 2 -CdS hybrids exhibit high stability and reusability during the catalytic reaction. • Efficient charge separation and transfer were observed in the composites. Metal-organic frameworks (MOFs)/semiconductor hybrids have attracted attention in photocatalysis. Herein, we report a new strategy to use thiol-laced UiO-66 (UiO-66-(SH) 2) as a porous and functional support for anchoring CdS quantum dots (QDs) (size: 0.5/3 nm). Cd2+ ions are firstly absorbed into the cavities of UiO-66-(SH) 2 MOFs via coordinating to the thiol groups in the presence of a base to produce UiO-66-(S-Cd) 2 , then thiourea is added to form UiO-66-(S-CdS) 2 (abbreviated as UiOS-CdS). It is clearly revealed by ultrafast transient absorption spectroscopy that the thio linkage between UiO-66 and CdS acts as an effective transfer bridge of charge carriers, which greatly promotes the interface transfer process of photogenerated electrons and holes, boosting the photocatalytic hydrogen production performance from water splitting. The optimized UiOS-CdS exhibits a photocatalytic H 2 production rate of 153.2 μmol h−1 (10 mg of catalyst) under visible-light irradiation (λ > 420 nm) in the absence of nobel metal co-catalyst, corrsponding to an apparent quantum efficiency of 11.9% at 420 nm. This work may provide an effective strategy to construct QDs-linker-MOFs stylephotocatalysts for efficient energy conversion. [ABSTRACT FROM AUTHOR]

Few‐layer porous graphene is a promising material for a variety of fields. However, the synthesis of few‐layer porous graphene is a great challenge. Here we report a feasible green path to produce few‐layer porous graphene, which was exfoliated from high‐pressure graphite balls onto microspheres with rough surfaces by a mild rolling transfer process. Ordinary ball milling equipment was adopted for the low‐speed (100 rpm) ball–microsphere rolling transfer process. The rolling time (<10 min) was controlled to obtain porous graphene instead of graphene. The porous graphene on the exfoliating microspheres was then easily dispersed in solution by bath sonication. The product contains very few impure functional groups. The hole size and layer distribution of the few‐layer porous graphene have been demonstrated to be 2.37±1.17 nm and 2.4±0.7 layers, respectively, and can be adjusted by redesigning the surface of the microspheres. [ABSTRACT FROM AUTHOR]

Due to the miniaturization of microelectromechanical systems, nanoelectromechanical systems and molecular devices, the problem of vacuum insulation becomes more and more prominent. The nanoscale thermal effects caused by electron emission and electric current Joule heat under high electric fields lead to gasification and migration of material in the device. In this work, a coupled molecular dynamics–electrodynamics method is used to simulate the thermal evaporation of nanotips under high electric field. Moreover, Cu nanotips with different initial geometries and different macroscopic electric fields are modelled. The deformation and damage mechanisms of nanotips under high electric field are discussed. Our simulations show that the aspect ratio of nanotips has a significant influence on the thermal evaporation of nanotips. The thermal runaway occurring in picosecond time-scale plays an important role for the initiation of the vacuum breakdown. An empirical relationship is obtained between the on-set breakdown time and the macroscopic electric field and the geometry of nanotips by analysing the numerical results. [ABSTRACT FROM AUTHOR]

Doubly fed induction generators (DFIGs) are negatively affected by inter-turn short-circuit faults (ITSCFs) of rotor windings, and considering the safety and continuous operation of the wind turbine surveillance of DFIGs is of immense importance. For this purpose, an experimental platform was designed to detect ITSCFs in rotor windings. An experimental set-up with a 100 kW three-phase wound rotor induction machine and a condition monitoring system was constructed to obtain real-time experimental data. Different tapping points were set up to induce different ITSCFs. The rotor current was used for the analysis of the ITSCFs. First, spectral analysis was performed, and the ensuing results suggest that some harmonic frequency components were generated during the ITSCFs in addition to the fundamental frequency component. Additionally, the RMS value of the rotor current was measured during the process. In the next step, a wavelet coefficient of detail level 9 was found to be effective in analysing such harmonic frequency components in the rotor current. In the end, a new method based on the RMS value of the wavelet coefficient and the RMS value of the rotor current was proposed that can calculate the fault severity. It is concluded that such signal processing techniques are appropriate to detect ITSCFs and determine the fault severity in rotor windings in DFIGs. [ABSTRACT FROM AUTHOR]

Filling epoxy resin in glass fibre fabric with surface modified nano-Al 2 O 3 as a means of increasing the dielectric strength is investigated in this work. The 50 Hz breakdown strength with 3 wt% nano-Al 2 O 3 is shown to be 10% higher than the neat epoxy/glass fibre material and 4% higher than the neat epoxy. An improved interface bonding between the glass fibre and the epoxy is evidenced by SEM characterization. Based on a multilayer dielectric model, it is found that introducing nano-Al 2 O 3 to the epoxy resin can efficiently alleviate the dielectric constant mismatch between the epoxy and the epoxy-integrated glass fibre layer, which results in an improvement in the dielectric strength. [ABSTRACT FROM AUTHOR]

Summary: Energy storage media is the kernel for the rapidly developing new energy systems, while it remains a challenge to achieve admirable service capability at high temperature. This manuscript purposes crosslinking as an effective method to address the issue. The epoxy is innovatively studied as energy storage media in this research. We figure out that crosslinking density is a critical factor to determine its energy storage performance. With adequate crosslinking, attractive energy storage density/efficiency (6.9 J/cm3/90%@room temperature; 1.2 J/cm3/90% and 1.7 J/cm3/75%@100°C) can be achieved. However, excessive crosslinking density and lack of crosslinking point are found to induce obvious energy storage performance decaying at high electric field and high temperature, respectively. This manuscript demonstrates that the general epoxy materials can be used as energy storage media and concludes that proper crosslinking can improve the energy storage performance of polymers, which provides directions for future research on high‐temperature energy storage films. [ABSTRACT FROM AUTHOR]

Low dielectric constant materials are appropriate solutions to address the propagation delay problem in ultra-large scale integrated circuits. Herein, adamantane is applied to improve the dielectric properties of polybenzoxazines. Monomers synthesized from bisphenol-A, 4,4'-diphenol and 1-amino adamantane are developed for understanding the properties of polybenzoxazines at molecular level. We found that incorporating adamantane results in much lower dielectric constant and loss factor without sacrificing the glass transition temperature and thermal stability, which are potential alternates as new dielectric interlayer materials. [ABSTRACT FROM AUTHOR]

Alloy-/conversion-type metal oxides usually exhibit high theoretical lithium storage capacities but suffer from the large volume change induced electrode pulverization and the poor electric conductivity, which limit their practical applications. Hybrid/mixed metal oxides with different working mechanisms/potentials can display advantageous synergistic enhancement effect if delicate structure engineering is performed. Herein, atomically hybridized SnO 2 /Co 3 O 4 nanocomposites with amorphous nature are successfully cast onto the porous N -doped carbon (denoted as NC) nanoflakes through facile pyrolysis of the tin (II) 2-ethylhexanoate (C 16 H 30 O 4 Sn) and cobalt (II) 2-ethylhexanoate (C 16 H 30 O 4 Co) mixture within NC nanoflakes in air at 300 °C for 1 h. The Sn/Co atomic ratio and the loading amount of SnO 2 /Co 3 O 4 can be readily controlled, whose effect on lithium storage are investigated as anodes for lithium ion batteries (LIBs). Notably, SnO 2 /Co 3 O 4 @NC (R Sn/Co = 1.25) nanoflakes exhibit the most excellent lithium storage properties, delivering a reversible capacity of 1450.3 mA h g−1 after 300 cycles at 200 mA g−1, which is much higher than that of the single metal oxide SnO 2 @NC and Co 3 O 4 @NC electrodes. [ABSTRACT FROM AUTHOR]

• Dy was used as a dopant to modify MnFe mixed oxides for SCR catalyst for the first time. • The effects of Dy on the physical and chemical properties of MnFeO x were well disclosed. • MnFeDy-0.1 exhibited excellent low-temperature de-NO x performance and N 2 selectivity. • The reason dominated the NH 3 and NO adsorptions was revealed by DFT calculation. • The reaction mechanisms over the MnFeDy-0.1 were fully revealed by in-situ DRIFT. Recently, Mn-based catalysts doped/modified by rare earth elements for the selective catalytic reduction (SCR) of NO x with NH 3 are becoming a new research hotspot. In current work, Dy-doped MnFe oxides with the morphology of one-dimensional nanowire are successfully prepared by using electrospinning method for the first time, and the catalytic performances for the NH 3 -SCR of NO x are investigated in detail. It is found several positive factors are introduced due to the doping of Dy with an appropriate amount, such as the enhanced surface Mn4+ concentration and surface chemical adsorption of oxygen, the increased adsorption capacity for NH 3 and NO. Theoretical calculation reveals that the Dy-doping causes the larger depletion of electron density of mainly O atoms on the surface of MnFeDy than that of MnFe case, which energetically favors the adsorption of NH 3 and NO molecules. Our results fully confirm that Dy is an effective doped element of Mn-based catalysts for developing SCR catalysts with excellent low-temperature de-NO x performance. [ABSTRACT FROM AUTHOR]

Graphene is one of the most fantastic nanomaterials and has attracted much attention in various fields. The industrial applications are hindered since there is no effective path to produce scalable few layered graphene without functional groups. Here we report a simple effective green path, a soft ball-microsphere rolling transfer process, to produce bulk quantity of few layered graphene without functionalization. The as-produced graphene nanosheets have been demonstrated by height statistics to have 1–10 layers with average layers of 3.8 ± 1.9 and further confirmed by spectroscopic metrics. No functional groups or contamination have been introduced in the processes. No extra time-consuming purification processes are needed. About 70 mg graphene sheets were obtained from one 500 ml agate tank after process carried out at a speed of 100 rpm for 2 h. The exfoliation can be easily extended to industrial scale by using larger and more agate tanks without the sacrifice of yields. Image 1 [ABSTRACT FROM AUTHOR]

[Display omitted] • The reaction enthalpy of nitrogenation of Mo 2 TiC 2 or Mo 2 TiC 2 O 2 MXenes is highly endothermic. • Mo 2 Ti(C x N 1-x) 2 O 2 MXenes exhibit significantly high theoretical capacities for LIB on the bases of the multi-layer adsorption mechanism and the surface conversion reactions. • The diffusion energy barrier heights of Li+ on Mo 2 Ti(C x N 1-x) 2 and Mo 2 Ti(C x N 1-x) 2 O 2 MXenes are found to be less than 0.1 eV. We employ the first-principles calculations to investigate the atomic structure, thermodynamic stability, and electrochemical energy storage properties of N-doped carbonitride and nitride double-transition metal MXenes including Mo 2 TiC 2 -Mo 2 TiN 2 and Mo 2 TiC 2 O 2 -Mo 2 TiC 2 O 2 series. The thermodynamic feasibility for the ammonization or nitrogenation of Mo 2 TiC 2 and Mo 2 TiC 2 O 2 monolayers to obtain Mo 2 Ti(C x N 1-x) 2 and Mo 2 Ti(C x N 1-x) 2 O 2 MXenes are evaluated by calculating the reaction enthalpies as a function of N content. It is found that ammonization of both bare and O-terminated MXenes is exothermic with a N content below 50 at.%, and which is slightly endothermic above this dopant concentration. Meanwhile, reaction enthalpy of nitrogenation of Mo 2 TiC 2 or Mo 2 TiC 2 O 2 MXenes is highly endothermic. Theoretical capacities of bare and O-terminated Mo 2 Ti(C x N 1-x) 2 and Mo 2 Ti(C x N 1-x) 2 O 2 MXenes are predicted to be in the range from 160 mAh/g to 350 mAh/g for lithium ion battery (LIB). Due to the presence of a multi-layer adsorption mechanism and the surface conversion reactions, Mo 2 Ti(C x N 1-x) 2 O 2 MXenes exhibit significantly higher theoretical capacities for LIB than bare carbide, carbonitride and nitride MXenes. For all studied bare and O-terminated MXenes, their mean open circuit voltages are found to be less than 1.0 V. For the Li+ diffusion dynamics, the diffusion coefficients of Mo 2 Ti(C x N 1-x) 2 -Mo 2 TiN 2 and Mo 2 Ti(C x N 1-x) 2 O 2 -Mo 2 TiN 2 O 2 series are predicted to be 0.45 ∼ 0.75 × 10−8 m2/s and 0.1 ∼ 0.2 × 10−8 m2/s at 350 K, respectively. The diffusion energy barrier heights of Li+ on Mo 2 Ti(C x N 1-x) 2 and Mo 2 Ti(C x N 1-x) 2 O 2 MXenes are found to be less than 0.1 eV for energetically favorable migration pathways. Overall, we predict that O-terminated carbonitride MXenes could possess both high storage capacity and high charge/discharge rate capability for their use as electrode materials in LIB. [ABSTRACT FROM AUTHOR]

Rampant side reactions such as hydrogen evolution reaction (HER), corrosion and uncontrollable dendrite growth at anodes greatly impede the application of AZIBs. Herein, caprolactam (CPL) is employed as a crucial electrolyte medium to achieve the aim of highly reversible zinc anodes. CPL molecules exhibit a lower adsorption energy (−1.94 eV) than H 2 O and preferential binding with Zn anodes, resulting in a H 2 O-poor anode/electrolyte interface and an enhanced steric effect at the anode surface. This effect effectively hinders the contact between zinc metal and water molecules, consequently facilitating the uniform and controlled deposition of Zn2+. Furthermore, the combination between CPL and Zn2+ contributes to the optimization of solvation structures. Consequently, Zn/Zn batteries with CPL additives realized more than 2100 h stable cycling life under 1 mA cm−2 and 1 mAh cm−2. Moreover, Zn/Cu batteries with CPL additives achieved a reversible plating/stripping process for over 3000 cycles with high average CE of 99.4%. Besides, the assembled Zn/NH 4 V 4 O 10 full batteries using electrolyte of ZnSO 4 /CPL also exhibited excellent cyclic performance. The batteries yielded 77.1 mAh g−1 under the current density of 5 A g−1 after 1000 cycles. CPL demonstrates significant potential as a cost-effective and multifunctional electrolyte additive for achieving stable and reliable AZIBs. • Caprolactam (CPL) is proposed as a multifunctional electrolyte additive for AZIBs. • Theoretical calculations predict the mechanisms of CPL on Zn anodes. • CPL would effectively adsorb and form a protective layer on Zn anodes. • CPL would enhance the steric effect and promote the homogeneous deposition of Zn2+. • CPL would regulate the coordination environment of Zn2+ in the electrolyte. [ABSTRACT FROM AUTHOR]

• The solvation shell of electrostatic shielding cation was considered during the electrolyte design process. For a long time, the issue of dendrites in neutral/mild electrolyte-based aqueous zinc-ion batteries (AZIBs) has been a matter of concern. The dendrites resulting from this problem lead to short-circuit faults and significantly reduce the cycle life, which is quite troublesome. Here, we induce uniform Zn deposition by utilizing the enhanced electrostatic shielding effect of a hybrid additive of Na 2 SO 4 and EDTA. The limited tip-blocking effect of Na+ is due to the higher exchange reaction rate constant (k ex) of water molecules in the solvation shell. The coordination of EDTA can provide a more stable solvation shell for Na+, ensuring a stronger blocking effect on Zn deposition at the tip. This enhanced electrostatic shielding effect effectively suppresses the growth of Zn dendrites. In addition, EDTA also enters the solvation shell of Zn2+ and displaces some coordinated water molecules, allowing for more reversible Zn plating/stripping without significant side reactions occurring at the Zn anode. [ABSTRACT FROM AUTHOR]

With a theoretical specific capacity of 274 mAh·g−1, LiCoO 2 (LCO) is the favored cathode material for lithium ion batteries (LIBs) applied to electronic devices. However, the unfavorable transitions in phase of LCO structure at high voltage and the negative reactions occurring at the interface between cathode and electrolyte limit the practical applications of LCO. Therefore, we designed a novel tri-doping strategy to enhance the electrochemical performance of LCO at 4.6 V. The introduction of minimal quantities of Ti, Mg, and Sb to the transition metal (TM) layer of LCO resulted in a substantial increase in both the cycling stability and reversible capacity of LCO. The distribution of the doping elements in the modified LCO was also analyzed, and we found that Ti, Sb were uniformly distributed in the particles, while Mg tended to distribute at the near-surface area of the primary particles. Through the trace Ti-Mg-Sb tri-doping, the modified LCO cathode material can reach an initial discharge capacity of 222.9 mAh·g−1 between 3.0 and 4.6 V at 0.5 C with the capacity retention of 85.1% after 100 cycles. Moreover, the reversible capacity reached 114 mAh·g−1 at 10 C. This research offers a promising future for the development of 4.6 V LCO, as well as valuable insight into designing subsequently multi-element co-doping schemes for LCO cathodes. • The tri-doping modification strategy proposed in this study is based on the high-temperature solid-phase method for the industrial synthesis of high-voltage lithium cobaltate materials. • The distribution of doped elements among LCO particles was clearly displayed in this study. • Structural and chemical analysis of Ti-Mg-Sb tri-doped modified LCO clearly reveal the interactions between the doping elements. • The Ti-Mg-Sb tri-doping not only improves the cycling stability of LCO at 4.6 V, but also significantly enhances its reversible capacity. [ABSTRACT FROM AUTHOR]

Semiconducting layered phosphorus allotropes, such as black and violet phosphorus, are attracting more and more attention due to their predicted high hole mobilities (up to 1000 cm2 V−2 s−1). Violet phosphorus is assumed to be the intermediate structure between amorphous red phosphorus and black phosphorus. Is there any other reasonable and stable allotrope between them? An unexplored layered phosphorus allotrope, crimson phosphorus, has been predicted by the ab initio method. The crystal structure, elastic moduli, band structure, and charge carrier mobility of crimson phosphorus have been investigated. A higher symmetry with similar energetic stability and a narrower bandgap compared to those of violet phosphorus has been obtained by crimson phosphorus. The hole mobilities of crimson phosphorus have been calculated to be 5383 ( μ x ) and 1072 ( μ y ) cm2 V−1 s−1, which are much higher than those of violet phosphorus ( μ x : 91 cm2 V−1 s−1 and μ y : 27 cm2 V−1 s−1) and black phosphorus ( μ x : 3525 cm2 V−1 s−1 and μ y : 9 cm2 V−1 s−1). Additionally, much higher hole mobility anisotropy has been demonstrated by crimson phosphorus. Lower electron mobility compared with those of black and violet ones has been obtained by crimson phosphorus. The unique electronic properties of crimson phosphorus provide promising 2D materials for desired devices. [ABSTRACT FROM AUTHOR]

CoMoO 4 nanoparticles have been successfully in-situ formed and simultaneously embedded within the porous carbon nanofibers (CoMoO 4 /CNFs) via a facile electrospinning-annealing strategy. The porous CoMoO 4 /CNFs exhibit a specific surface area of 255.3 m2/g and a pore volume of 0.52 cc/g with average pore diameter of 43.5 nm. The carbon content in the CoMoO 4 /CNFs can be readily controlled by adjusting the annealing temperature. When examined as anode materials for lithium ion batteries (LIBs), the CoMoO 4 /CNFs demonstrate superior electrochemical performance, delivering a high reversible capacity of 802 mA h/g after 200 cycles at 200 mA/g and a high-rate capacity of 574 mA h/g at 2000 mA/g. The excellent lithium storage behavior can be attributed to the incorporation of CoMoO 4 nanoparticles into the porous N -doped graphitic carbon nanofibers, which efficiently buffer the volume changes of CoMoO 4 upon lithiation/delithiation and maintain the overall electrode conductivity/integrity. [ABSTRACT FROM AUTHOR]

The cobalt-free material of Bi3+-doped BaFeO 3- δ (BBFO) is synthesized and applied as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with proton conducting electrolyte Ba(Zr 0·1 Ce 0·7 Y 0.2)O 3 (BZCY). The as-prepared BBFO demonstrates a tetragonal structure with sufficient chemical compatibility, high thermal stability and low thermal expansion coefficient. BBFO exhibits higher electrical conductivity of 4.1 S cm−1compared to the parent material BaFeO 3- δ (BFO) of 3.5 S cm−1. The composite cathode BBFO-BZCY with the mass ratio of 7:3 presents a relatively low R p of 0.128 Ω cm2 at 700 °C in air. According to the oxygen reduction reaction process, the rate-determining step is transformed from charge transfer to oxygen gas (O 2) adsorption-dissociation with the rising temperature. In addition, the performance of the anode-supported cell NiO-BZCY∣BZCY∣BBFO-BZCY is 120 mW cm−2 as the thickness of electrolyte is 150 μm. It thus promises BBFO as a novel cathode for proton-conducting ceramic fuel cells. Oxygen reduction reaction of cathode on proton conducting electrolyte. (a) MIEC cathode; (b) A composite cathode of a proton-conducting oxide and a MIEC oxide. Image 1 • Cobalt-free and low thermal material of Bi 0·5 Ba 0·5 FeO 3- δ is applied as cathode. • Bi 0·5 Ba 0·5 FeO 3- δ exhibits higher electrical conductivity compared to the BaFeO 3- δ. • The composite cathode presents a relatively low R p of 0.128 Ω cm2 at 700 °C in air. • The oxygen reduction reaction process is analyzed as the temperature rises. [ABSTRACT FROM AUTHOR]

Many different phase structures have been discovered for silver iodides. The β and γ phases were found to be the most common ones at ambient conditions, while the rock-salt phase was found to be stable under pressures between 400 MPa and 11.3 GPa. Recently, the α phase was demonstrated to be stable under ambient conditions when the particle sizes were reduced to below 10 nm. However, no other phase has been reported to be stable for silver iodides under ambient conditions. Rock-salt and helix structures have been found to be stable under ambient conditions in this study. The structures have been characterized by elemental mapping, Raman scattering, and high-resolution transmission electron microscopy. The stabilities of these structures were also confirmed by molecular dynamics and density functional theory. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Surface functionalization POSS modulate interfacial compatibility and trap. • Intermolecular interaction energy and electrostatic potential affect trap energy. • Interfacial compatibility and trap affect charge transport and dc breakdown. • DC electrical breakdown increases with the deeper trap energy. • The conclusions contribute to tailoring expected electrical insulation composite. Abstract Incorporating polymeric matrix with inorganic fillers is a preferential method to improve electrical properties, while functionalization on filler surface has always been employed. In this study, two interfacial microstructures were constructed by using different functionalized polyhedral oligomeric silsesquioxane (POSS) and electrical properties of polypropylene (PP) based composites were evaluated. It is found that the electrical properties are closely related to interfacial compatibility and trap. The improved electrical breakdown strength corresponds with the composite possessing better intermolecular compatibility and deeper traps. The molecular simulation further reveals that interfacial compatibility and trap energy are affected by interaction energy and electrostatic potential between functionalized groups and PP molecular. The greater interaction energy leads to more compatible interfacial microstructure, and larger electrostatic potential leads to deeper trap energy with enhanced trapping effect, thereby restraining the charge carriers injection and migration, which synergistically leads to improved electrical breakdown strength. Contrastive interfacial traps and electrical properties of PP/POSS composites by different functionalized groups reveal the effect of interfacial compatibility. Thorough understanding of the functionalized groups and interfacial effects are beneficial for tailor-synthesizing composites with expected electrical properties. [ABSTRACT FROM AUTHOR]

Highlights • A highly sensitive sensor for H 2 O 2 is developed based on iron sulfide/graphene. • An ultralow detection limit of 0.5 nM and wide dynamic range are achieved. • Performance of directly grown CVD vs. epitaxial graphene layers is compared for the first time. • Catalyst-free CVD graphene exhibits significantly higher performance than n- and p-type epitaxial graphene. • The developed sensor is used for in situ detection of E. coli response to oxidative stress caused by heat shock. Abstract Hydrogen peroxide (H 2 O 2) is one of the most important redox-active metabolites in biological processes, from cell signaling to oxidative stress. Incorporation of catalytic nano-phase heterostructures can significantly improve the detection limit of H 2 O 2 electrochemical sensors. Here, we report an iron sulfide (FeS x)/graphene heterostructure for detection of H 2 O 2 down to ∼500 picoMolar p M , with a dynamic range over six orders of magnitude. By relying on the Fenton reaction, the developed catalyst enables selective detection of H 2 O 2 vs. common redox-active metabolites in physiological condition. Electrochemical analysis reveals a strong substrate-dependent performance, where the type and doping of the graphene layer dramatically impact sensitivity. Specifically, for the first time, the electrochemical performance of chemical vapor deposited versus epitaxial graphene (EG) layers is examined and compared in a systematic way. The results demonstrate that a heterostructure of FeS x with chemical vapor deposited graphene (CVD-G) exhibits the highest reduction in charge transfer resistance (more than 16 ×), leading to a significantly higher sensitivity compared to n-doped and p-doped EG. Furthermore, the excellent sensitivity and material stability of the developed heterostructures enable in situ detection of redox changes due to heat shock-induced oxidative stress on E. coli cells. Since the developed heterostructures are directly-grown, they can be patterned with nanometer-scale resolution. Hence, this work can open up new possibilities for developing ultracompact devices for monitoring redox changes in situ , with high spatial resolution. [ABSTRACT FROM AUTHOR]

Abstract Protonic ceramic fuel cells offer the potential for environmentally sustainable and cost-effective electric power generation. However, the power outputs of protonic ceramic fuel cells are far from the requirements due to the lack of active cathodes. In this work, porous thin sheets Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ (x = 0.1, 0.3 and 0.5) are synthesized by a modified pechini method and investigated as cathode materials for protonic ceramic fuel cells. Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ show high electrical conductivities and excellent chemical compatibility with Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 electrolyte. The maximum electrical conductivity of Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ reaches 202 S cm−1 in air at 750 °C. The detailed mechanism for oxygen reduction reaction reveals that the rate-limiting step of oxygen reduction reaction is transformed from charge transfer to O 2 adsorption-dissociation with temperature rising or Ca doping. The composite cathode Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ -Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 presents a relatively low polarization resistance of 0.07 Ω cm2 at 750 °C in air. The power density of the anode-supported cell of NiO Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 ∣Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 ∣Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ-Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 is 798 mW cm−2 as the electrolyte thickness is about 150 μm. The prepared Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ oxides are promising candidates as high-performance cathodes for protonic ceramic fuel cells. Graphical abstract Image 1 Highlights • Increasing proper Ca doping at A -site is improving the conductivity of CYFC. • The detailed mechanism for oxygen reduction reaction is analyzed. • The R p of composite cathode C3YFC-BZCY was 0.07 Ω cm2 in air at 750 °C. • The peak power density is 798 mW cm−2 at 750 °C as the thickness of BZCY is 150 μm. [ABSTRACT FROM AUTHOR]

Graphene‐coated silicon nanoparticles with polydopamine buffers have been designed and successfully fabricated as anodes for lithium ion batteries, where the polydopamine was grown on the silicon nanoparticles and then coated with graphene layers. The expansion cavities for silicon nanoparticles during charging and discharging process are provided by the polydopamine buffer layers. The outermost graphene coating layers not only keep the pulverized silicon particles together without disintegration, but also improve the electric conductivity of silicon nanoparticles. Silicon nanoparticles of an industrial product level with different size distributions and oxidation layers were used in this work. High electrochemical performances with specific capacities of 1100 mAh g−1 were achieved by the designed silicon composites with polydopamine and graphene after 550 cycles at a current rate of 200 mA g−1. Graphene‐coated silicon nanoparticles with polydopamine buffers have been designed and successfully fabricated as anodes for lithium ion batteries. A specific capacity around 1100 mAh g−1 has been achieved by the Si@PDA@Gra anodes at a current rate of 200 mA g−1 after 600 cycles. Silicon nanoparticles of an industrial product level could be used without further treatment. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we present an in-situ measurement method to directly observe the distribution of the local electric field between vacuum microgaps. The measurement was performed in-situ inside a high resolution scanning electron microscope (SEM), and the nature of the local electric field was characterized through secondary electron contrast images with the aid of Rutherford scattering theory. Based on the regular fringes in these contrast images, the distribution of the local electric field could be extracted from the contour lines of the fringes while the magnitude of the local electric field could be evaluated qualitatively by the gradient of the contour lines. The finite element method (FEM) simulation and the three-electrodes imaging experiment were also conducted, and the obtained two-dimensional electric field distribution agreed well with the FEM simulation, suggesting that the in-situ visualization technique could be useful for determining the local field enhancement behavior for various geometrical configurations and microscale structures. A physical mechanism for the local electric field mapping is suggested. This study demonstrates the potential of SEM imaging for obtaining information about the local electric field within microelectronic structures and devices. [ABSTRACT FROM AUTHOR]

Microscale gas breakdown plays a critical role in microplasma generation for numerous applications and device lifetime for miniaturized electronics. This communication extends a previous investigation of pulsed breakdown morphology [G. Meng et al., Phys. Plasmas 25, 082116 (2018)] by providing further insight into the spatio-temporal dynamics of pulsed gas breakdown for different gap distances using an in-situ electrical-optical measurement method. Time-resolved sequential images and the corresponding photon number distributions are obtained to demonstrate the dynamic evolution of the breakdown channel morphology and the ionization intensity during breakdown development. For a 15 μm gap, breakdown transitions from a spot area on both electrode surfaces to a broad discharge region comprised of filamentary main breakdown channel (∼2.00 μm) and surrounding weak ionization area due to the local field enhancement. For a 2 μm gap, it transitions from a thin channel (∼1.09 μm) to a wider and uniform channel (∼2.14 μm) because the electric field is more uniform at smaller gaps. Interestingly, the main breakdown channel width at the instant of breakdown is independent of the gap width. For the 2 μm gap, field emission dominates the initial stage of breakdown and collision ionization (α process) dominates during breakdown development, while the Townsend avalanche dominates the breakdown process for the 15 μm gap. We apply a simple asymptotic theory to quantify the relative contribution of these phenomena and predict that breakdown will follow Paschen's law for gaps larger than 17.8 μm. [ABSTRACT FROM AUTHOR]

Lithium cobaltate (LiCoO 2) is the favored cathode material due to its exceptional volumetric energy density. An effective approach to enhancing the energy density of lithium-ion batteries is to elevating the operating voltage of LiCoO 2. However, lithium cobalt oxide will experience unfavorable phase transitions from O3 phase to H1–3 phase, as well as irreversible oxygen oxidation reactions at high voltages, which deteriorate its electrochemical performance. Here, we propose a triple-doping strategy involving metal elements Ti, Mg, and non-metal elements B. Introducing Mg and Ti into the LiCoO 2 lattice not only suppress hazardous phase transitions during high-voltage cycling, but also enhance surface lattice oxygen stability and prevent the escape of lattice oxygen during high voltage cycling. Moreover, it increases the c-axis spacing, which improve the diffusion rate of Li+ ions during cycling. The B doping helps metal elements Mg and Ti better diffuse into the particle interiors, while reducing the size of LiCoO 2 particles. After Ti-Mg-B triple-doping, the LiCoO 2 cathode material has an initial discharge capacity of 233.7 mAh·g−1 within the range of 3.0 - 4.6 V at 0.5 C, with the residual capacity of 183 mAh·g−1 after 100 cycles. The modified sample still remain a reversible capacity of 94.7mAh·g−1 at a current density of 10 C. Our studied doping strategy significantly improves the cycling stability of LiCoO 2 at 4.6 V, while further enhancing the capacity of lithium batteries. [ABSTRACT FROM AUTHOR]

Environmental concerns raise the urgent demand of recyclable materials for electrical and electronic applications. Epoxy and its glass fiber reinforced composites are the most widely used materials in these areas, but are generally unrecyclable. Herein, we reported a recyclable epoxy vitrimer and its glass fiber reinforced composite by using salen agent and DGEBA-type epoxy to ensure its molecular design flexibility and industrial adaptability. Comparing with the conventional amine-cured epoxy, the obtained epoxy vitrimer shows a higher glass transition temperature of 140 °C, a superior tensile strength of 86.7 MPa and an enhanced breakdown strength (180 MV m−1). Furthermore, based on the reversible imine-imine and amine−imine exchange reactions, the epoxy vitrimer could be recycled by both mechanical and chemical methods. An admirable recycling efficiency was achieved based on electrical properties. Moreover, its corresponding glass fiber reinforced composites could be recycled in a closed-loop way while the reclaimed fabric was comparable to its origin. This study demonstrates the potential application of salen agent to develop fully recyclable electrical insulating component and opens a window to further improve the material properties of epoxy vitrimer based on the great design flexibility of salen agent. [Display omitted] • Salen was able to develop epoxy vitrimer with commercial DGEBA. • Salen enhances the thermo-mechanical and insulating properties of vitrimer. • The vitrimer displays admirable mechanical and chemical recycling efficiency. • Its fiber reinforced composite can be recycled by a closed-loop process. • The vitrimer is potential for application in eco-friendly advanced insulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CsCu 2 I 3 /g-C 3 N 4 (CCI/CN) is successfully constructed by an in-situ hot-injection method for the first time. • The resultant CCI/CN presents an enhanced photocatalytic H 2 generation of 2212 umol/g/h. • A unique N-I bond is formed by the connection of N in CN and I in CCI at the interface between CN and CCI. • N-I bond serves as a fast channel for the transfer of photogenerated electrons to establish a type II mechanism. Lead-free halide perovskites have enormous superiority in photoelectric devices, but low photocatalytic hydrogen evolution (PHE) hinders their application in photocatalysis. Here, a heterojunction composed of CsCu 2 I 3 (CCI) perovskite and graphite carbon nitride (CN) is constructed by in-situ hot-injection method for the first time. The resultant CCI/CN presents a significantly enhanced PHE performance from hydroiodic acid (HI) splitting with a PHE rate of 2212 umol/g/h, which is four times higher than CCI and nearly ten times higher than CN. It is revealed that a unique N-I bond is formed by the connection of N in CN and I in CCI at the interface between CN and CCI, which serves as a fast channel for the transfer of photogenerated electrons to establish a type II mechanism, effectively promoting the PHE performance. This study provides ideas and methods for the construction of type II photocatalyst for hydrogen production using lead-free halide perovskite. [ABSTRACT FROM AUTHOR]

Metal oxides with high crystallinities have been reported to exhibit better ion storage performances, which demonstrates the significance of controlling the crystallinity as a facile and economical method to synthesize high-performance electrode materials. However, the relationship between crystallinity and charge storage property remains unclear for transition metal disulfides (TMDs). In this work, we employ a series of MoS 2 -based electrode materials with different crystallinities as a case to study the trend in sodium ion (Na+) storage characteristics of TMDs with varying crystallinity. Structure characterizations prove that the crystallinity of MoS 2 improves with the increase in calcination temperature. Electrochemical tests and kinetic analyses indicate that MoS 2 -based electrode material with higher crystallinity shows better high-rate Na+ storage performance and stronger pseudocapacitive response. Finally, we carry out density functional theory calculations to study Na+ diffusion behaviors in MoS 2 with different crystallinities, and we prove that MoS 2 with higher crystallinity possesses better Na+ diffusion kinetics. The conclusions of this work provide beneficial guidance for the rational design of TMDs toward superior high-rate ion storage. • The relationship between the crystallinity of MoS 2 and Na+ storage performance was investigated for the first time. • MoS 2 with higher crystallinity showed better electrochemical characteristics. • A lower Na+ diffusion energy barrier was found in MoS 2 with higher crystallinity. • MoS 2 /heteroatom-modified carbon composite showed potential in practical use. [ABSTRACT FROM AUTHOR]

The structural and electrochemical properties of the layered perovskite oxides LaSrCo 1−x Sb x O 4 (0≤x≤0.20) were investigated to study the effects of substituting Sb for Co for application as cathode materials in intermediate temperature solid oxide fuel cells (IT-SOFCs). The results of crystal structure analyses show the maximum content of Sb in LaSrCo 1−x Sb x O 4 to be 0.05 as a pure single phase. XPS shows that Co and Sb in LaSrCo 0.95 Sb 0.05 O 4 may possess mixed-oxidation states. The electrical conductivity increased greatly after Sb substitution. An improvement in the cathode polarization ( R p ) values is observed from the Sb-doped sample with respect to the undoped samples. For example, R p of LaSrCo 0.95 Sb 0.05 O 4 on LSGM was observed to be 0.16 Ω cm 2 at 800 °C in air. The main rate-limiting step for LaSrCo 0.95 Sb 0.05 O 4 cathode is charge transfer of oxygen atoms. These results indicate that Sb can be incorporated into LaSrCo 1−x Sb x O 4 based materials and can have a beneficial effect on the performance, making them potentially suitable for use as cathode materials in IT-SOFCs. [ABSTRACT FROM AUTHOR]

Sodium-ion capacitors (SICs) have been viewed as promising energy storage devices because of their high power/energy density, cycling stability and cost-efficiency, but they are also restricted by the unmatched reaction kinetics between the battery-type anode and capacitor-type cathode. Herein, we present a novel way to enhance the pseudocapacitive storage behavior and reaction kinetics of TiO 2 -based anode via Mo-doping and carbon hybridization, using the Mo-doped titanium metal-organic framework (Ti-MOF, MIL-125) as the precursor. Appropriate amount of Mo-doping (Mo:Ti = 1:9) induces the shape evolution from the round MIL-125 nanotablets to square Mo-MIL-125 nanocubes, which can be readily converted to Mo-doped TiO 2-x @carbon composite with conformal morphology (namely, Mo 0.1 -TiO 2-x @C). Mo-doping increases the concentration of Ti3+/oxygen vacancy and decreases its crystallinity, which greatly enhances the reaction kinetics and sodium storage performance. When examined in half-cells, the Mo 0.1 -TiO 2-x @C anode exhibits higher pseudocapacitive contribution (∼85%), higher reversible capacity (216 mAh g−1 at 0.5 A g−1), and better cycling and rate capability (185 mAh g−1 even after 3000 cycles at 1 A g−1). When paired with commercial activated carbon (AC) as cathode, the Mo 0.1 -TiO 2-x @C//AC SICs deliver a maximum energy density of 269.37 Wh kg−1 at a power density of 80.4 W kg−1 and 61.75 Wh kg−1 even at a high power density of 5421.95 W kg−1. [Display omitted] • Approximate Mo-doping induces the morphology change of MIL-125 from round tablet-like to square cube-like shapes. • Mo-doping TiO 2-x @C nanocubes display more defective Ti3+ species and increased oxygen vacancies. • Mo 0.1- TiO 2-x @C nanocubes display predominantly pseudocapacitive sodium storage behavior. • Mo 0.1- TiO 2-x @C//AC SIC displays a high operating voltage of 4 V and a maximum energy density of 80.4 Wh kg−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • MnFeO x nanobelts are bimetallically modified with Nb and Nd for the first time. • The MnFeNb 0.2 Nd 0.1 O x achieves an improved NO x conversion and an enhanced tolerance of SO 2. • The rational design of Nb and Nd enhances the adsorption of NH 3 and NO and reduces the adsorption of SO 2. • The de-NO x reaction over MnFeNb 0.2 Nd 0.1 O x follows both E-R and L-H mechanisms. Nitrogen oxide (NO x) is one of the key factors contributing to air pollution, and selective catalytic reduction with ammonia (NH 3 -SCR) is widely used for denitrification (de-NO x). To effectively deal with the NO x pollution, it is urgent to develop efficient catalyst working at below 300 °C with a wide operating temperature window. Herein, a series of ferromanganese oxides (MnFeO x) nanobelts are bimetallically modified with niobium (Nb) and neodymium (Nd) for the first time via electrospinning method. The resultant MnFeNbNdO x catalysts present improved low-temperature de-NO x performance and sulfur dioxide (SO 2) tolerance, particularly MnFeNb 0.2 Nd 0.1 O x who achieves a NO x conversion up to over 90 % during the range of 120–330 °C and an enhanced tolerance of water (H 2 O) and SO 2. Experimental and theoretical calculations confirm that strong adsorption of nitric oxide (NO) and ammonia (NH 3) and weak adsorption of SO 2 with the synergy of Nd, Nb and Mn enable MnFeNb 0.2 Nd 0.1 O x excellent SCR activity and good SO 2 tolerance. In-situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) further reveal that the de-NO x reaction over MnFeNb 0.2 Nd 0.1 O x follows both Eley-Rideal (E-R) and Langmuir-Hinshel-wood (L-H) mechanisms. This study will inspire the further design and study of the synergy of transition metals and rare earth elements for de-NO x. [ABSTRACT FROM AUTHOR]

• Vanillin triggered degradable epoxy was prepared through a one-pot method. • The degradable materials show comparable properties with the commercialized epoxy. • Epoxy containing Schiff base has admirable degradability in acidic THF solutions. A facile one-pot synthesis method to prepare degradable epoxy materials is introduced in this study. Rather than elaborately preparing new epoxies or hardeners, this method developed here is based on a conventional epoxy-amine system, which has better adaptability. Vanillin, a bio-based chemical was selected to trigger the degradation by reacting with epoxy and amine to generate Schiff base linkage. The fabricated degradable materials show comparable thermal, mechanical and insulating properties with their amine-cured counterpart, therefore can be applied as an eco-friendly substitute. A high degradation rate was achieved at a specific acid/organic solvent ratio, while the materials display admirable acidic resistance under other circumstances, which is beneficial for practical application. [ABSTRACT FROM AUTHOR]

A layered perovskite electrode material, La 0.6 Sr 1.4 MnO 4 + δ (LSMO 4 ), has been studied for intermediate temperature symmetrical solid oxide fuel cells (IT-SSOFCs) on La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 − δ (LSGM) electrolyte. The chemical compatibility tests indicate that no reaction occurred between LSMO 4 oxide and LSGM electrolyte at temperature up to 1000 ° C both in air and 5% H 2 . The lower conductivity in 5% H 2 and higher conduction activation energy than those in air would be caused by poorer overlap of both σ and π bonds. DFT + U calculations also show that oxygen vacancies which formed in reducing atmosphere may block the 3D hopping path for electrons or holes through Mn–O–Mn chains. For LSMO 4 electrode, SEM results indicate that the electrode formed good contact with the electrolyte after being sintered at 900 ° C for 2 h. At 800 ° C, the polarization resistance of the LSMO 4 cathode is about 0.87 Ω cm 2 in air, while the polarization resistance of the LSMO 4 anode is about 2.07 Ω cm 2 in 5% H 2 . LSMO 4 exhibits better electrochemical activity for oxygen reduction than that for hydrogen oxidation. A cell with LSGM electrolyte, LSMO 4 –LSGM mixture as anode and cathode simultaneously displays a maximum power density of 59 mW cm − 2 at 800 ° C. [ABSTRACT FROM AUTHOR]

A fluorine substituted healable silicone elastomer is developed as actuator dielectric material in this study. The silicone possesses both high electrical breakdown strength (>65 kV/mm) and admirable intrinsic permittivity (more than 4.3 at 50 Hz). Moreover, with fluorine stimulated carbamate bond exchange, the networks of prepared silicones can be recovered with more than 80% of mechanical and insulating reprocessing efficiency. Importantly, electrical breakdown damage is able to be healed at high healing efficiency (90%), which overcomes the classical dilemma between insulation and healability. The study provides a new way to enhance the performance and reliability of actuator polymer dielectrics, especially at high electric field intensity. [Display omitted] • Fluorine substitution is found to promote healability of silicone. • Not only mechanical damage, but also electrical breakdown damage can be healed. • The electrical and mechanical properties are comparable with commercial silicone. • Effects including fluorine content and crosslinking on properties were studied. [ABSTRACT FROM AUTHOR]

The inner cavities of carbon nanotubes (CNTs) have attracted much attention for one-dimensional structures and their unique properties. The encapsulation of hetero-structures into CNTs is the foundation for potential applications. Solution and vapor methods have been well adopted for CNTs encapsulations. The solution method is restricted to its low encapsulation yield. Only chemicals with relatively low sublimation points under low pressures and low activity have been demonstrated to be encapsulated into the inner cavities of CNTs by vapor methods. No effective encapsulation method for most metals has been explored so far. Now, a widely applicable metal encapsulation method, micro-current electrochemical deposition, has been demonstrated to encapsulate lithium, sodium and potassium metals into CNTs with high yield. The volumetric encapsulation yields of lithium, sodium and potassium metal have been demonstrated to be higher than 65%. [Display omitted] • A micro-current electrochemical deposition method has been reported to encapsulate metals into MWCNTs. • The encapsulation yields of Li, Na and K have been demonstrated to be about 68%, 74%, and 75%, respectively. • The elemental status of the encapsulated metals was confirmed by elemental maps and hydrolysis reaction to yield hydrogen. • The encapsulation method has been explored to be an effective and widely applicable encapsulation method for metals. [ABSTRACT FROM AUTHOR]

Electrical breakdown is a classical failure mod of epoxy when applied as insulating materials in electrical engineering, which greatly threatens the reliability of power equipment. However, as a stiff polymer, the healing of epoxy is usually considered to be inaccessible. In this study, new epoxy networks with electrical breakdown healability were developed for power equipment insulation. The dynamic networks are generated by amine-terminated ring-opened epoxies and bi-functional isocyanates, which endows good reprocessability and healability. Artificial puncture was first made to simulate electrical breakdown features and clarify the influence of failure shape on healability. Electrical damage was carried out afterwards, the thru-hole generated by electrical breakdown is able to be recovered after healing within 10 min. A high healing efficiency of about 90% based on breakdown strength is observed. With temperature and pressure stimulation, the network dissociated reversibly to rejoin the separated surface of the breakdown holes. Meanwhile, the carbon residue generated by electrical discharge is squeezed and isolated by flowed chain segments. Moreover, by replacing bisphenol-A epoxy resin with the hydrogenated epoxy resin of a lower C/H ratio, less carbon residue can be detected after electrical breakdown and improved healability on morphology and insulation properties is discovered. [Display omitted] • Healing of electrical breakdown in a stiff polymer is reported for electrical equipment applications. • A two-step approach is developed to fabricate the healable and reprocessable epoxy dynamic network. • A high healing efficiency of around 90% in electrical breakdown strength is found in the epoxy network. • Lower C/H ratio leads to less carbon residue after electrical breakdown, which further improves healability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A one-step hydrothermal method is developed to synthesize CdS/ZnS-NiS for the first time. • The three components (CdS, ZnS and NiS) are fully combined together at nano-scale. • The optimized CdS/ZnS-NiS exhibits a photocatalytic H 2 evolution rate of 604.4 μmol·h−1. • Synergistic effect between CdS/ZnS heterostructure and NiS co-catalyst boosts H 2 evolution. Introducing co-catalyst and constructing heterostructure are two of the most promising strategies in improving the photocatalytic H 2 evolution performance of semiconductors. However, it has always been a great challenge to develop a facile and low-cost system to facilitate the highly efficient synergistic effect between co-catalyst and heterostructure. Herein, co-catalyst NiS decorated ZnS/CdS heterostructure (CdS/ZnS-NiS) has been fabricated by using a facile one-pot hydrothermal procedure for the photocatalytic H 2 evolution from water splitting. As a result, CdS, ZnS and NiS contact closely with each other at nano scale to assemble into fluffy porous nanocomposite, the optimized CdS/ZnS-NiS exhibits a high hydrogen evolution rate of 60.44 mmol·h−1g−1 without the addition of extra noble metal co-catalyst, which is about 22.3 times higher than that of pure CdS and much higher than that of 1% wt Pt decorated CdS/ZnS (52.36 mmol·h−1g−1). One-pot fabrication process allows the formation of intimate contacted interface between different components, contributing to the sufficient exposure of active reaction sites. Moreover, noble-metal-free co-catalyst NiS distributes uniformly in both surface and inner region of porous nanocomposite. The synergistic effect between the intimately contacted heterostructure and co-catalyst boosts the separation and utilization of photogenerated charge carriers, resulting in a dramatically enhanced H 2 evolution ability. This work provides a facile pathway to uniformly introduce noble-metal-free co-catalyst in heterostructure and gives out a paradigm in constructing high active solar energy conversion system. [ABSTRACT FROM AUTHOR]

Abstract: La0.8Sr1.2CoO4+δ (LSCO4) material with K2NiF4-type structure has been synthesized via a citric–nitrate process and characterized. Composite materials La0.8Sr1.2CoO4+δ -Ce0.9Gd0.1O2−δ (CGO) (LSCO4–CGO) have been prepared and evaluated as cathode for intermediate temperature SOFC (IT-SOFC) based on La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolytes. LSCO4 oxide is chemically compatible with CGO and LSGM electrolyte at temperature up to 1000 °C. Compared with the pure LSCO4, the optimum composition of LSCO4–35 wt % CGO exhibits better electrochemical activity for oxygen reduction. Also, for LSCO4–35 wt % CGO electrode, SEM results suggest that better microstructure is obtained and the electrode forms good contact with the electrolyte after sintering at 1000 °C for 2 h. At 750 °C, the polarization resistance of the LSCO4–35 wt % CGO composite cathode is about 0.21 Ω cm2 in air. A cell with a 1.2 mm thick LSGM electrolyte, NiO as anode, and LSCO4-35 wt % CGO as cathode displays a maximum power density of 515 mW cm−2 at 750 °C. These results indicate that LSCO4–CGO composite materials are promising cathode candidates for intermediate-temperature solid oxide fuel cells with LSGM electrolyte. [Copyright &y& Elsevier]

Abstract: Cathodes with high catalytic activities are usually required for the preparation of high performance intermediate temperature (600–800°C) solid oxide fuel cells (IT-SOFCs). In the present study, a new kind of cathode material for IT-SOFCs based on Ba(Zr0.1Ce0.7Y0.2)O3 (BZCY) electrolytes is prepared through solid state reduction of the K2NiF4 structured LaSrCoO4−δ with CaH2. Structural analysis by XRD reveals that the cell parameters of LaSrCoO4−δ become larger after the reduction. And oxygen stoichiometry of 3.57 is determined by iodometric titration for the CaH2 reduced phase (marked as H-LaSrCoO4−δ ). The electrochemical properties of both the H-LaSrCoO4−δ –BZCY and the LaSrCoO4−δ –BZCY composite cathodes are investigated through ac impedance spectroscopy and dc polarization measurements. At 750°C, the H-LaSrCoO4−δ –BZCY cathode exhibits a polarization resistance of 0.229Ωcm2, which is about one third smaller than that of the LaSrCoO4−δ –BZCY cathode. Meanwhile, cathodic overpotential of 25mV is obtained for the H-LaSrCoO4−δ –BZCY cathode under a current density of 100mAcm−2 at 750°C. This value is much lower than 70mV of the LaSrCoO4−δ –BZCY cathode obtained at the same condition. Subsequent study on the cathodic reaction process implies that the better electrochemical properties of the H-LaSrCoO4−δ –BZCY cathode can be attributed to the higher oxygen vacancy concentration in the H-LaSrCoO4−δ lattice that enhances some key steps of the oxygen reduction reaction (ORR). [Copyright &y& Elsevier]

Abstract: Solid oxide fuel cell (SOFC) is one of the most promising technologies for a clean and secure source of energy in future due to its high energy efficiency and outstanding fuel flexibility. The search for new materials operating at low-temperature in order to make SOFCs economically competitive is a great challenge facing us today. In this report, atomistic computer simulation based on density functional theory (DFT) has been used to predict the formation of oxygen vacancy and the strong oxygen adsorption kinetics mechanisms in LaSrCoO4. The optimal adsorption configurations as well as the adsorption energies for oxygen molecule adsorption on various sites of LaSrCoO4 (010) surface were derived. Furthermore, a strong hybridization between Co and O and shorter Co–O bond length for molecular adsorption were obtained by analysis of density of states. The calculated results imply that LaSrCoO4 could serve as possible cathode material due to its low formation and migration energies of oxygen vacancies. [Copyright &y& Elsevier]

[Display omitted] • Tri-arm CdS/ZnS nanorods were synthesized by a facile deposition for the first time. • The optimized CZS 0.5 presented H 2 evolution rate of 805.5 μmol/h with the AQE of 50.61%. • Tri-arm CdS and ZnS formed an analogous type-II charge transfer mechanism. • The dodecylamine molecules adsorbed on CdS can efficiently enhance the proton adsorption. • The type-II heterostructure and proton adsorption jointly contributed to enhancing activity. A new photocatalyst, the tri-arm CdS/ZnS core–shell nanorod, is carefully designed for the first time, where tri-arm CdS nanorods are decorated by dodecylamine (DDA) molecules and then wrapped in an intermittent ZnS shell. The resultant photocatalyst with a CdS/ZnS mole ratio of 0.5 (CZS 0.5) presents a significantly improved H 2 evolution rate of 726.0 μmol/h (3 mg of catalysts, equal to 242.0 mmol/g/h) in the absence of co-catalysts, which is currently the highest value in CdS-based catalysts. The apparent quantum efficiency of CZS 0.5 reaches 50.61% at 380 nm. The significantly enhanced photocatalytic performance can be attributed to a win–win situation between the analogous type-II mechanism formed in the CdS/ZnS heterojunction and the H+ adsorption resulting from the DDA molecules. Due to the analogous type-II mechanism, photogenerated electrons are transferred from the ZnS shell to the CdS nanorod. Owing to the decoration of DDA, many H+ ions are adsorbed on CdS. Thus, the photogenerated electrons gathered in CdS can be captured quickly and in a timely manner by the adsorbed proton H+ to produce hydrogen, which effectively suppresses the recombination of photogenerated electrons and holes. This study may bring new insights for developing other photocatalysts with high performance by using small organic molecules. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries are being regarded as a kind of promising next-generation rechargeable battery technology for their high energy density as well as high theoretical specific capacity. However, the shuttle effect of soluble polysulfides and the poor electrical conductivity of sulfur cathodes significantly impedes the energy efficiency and cycle performance of this battery system. In this work, the anchoring behavior of polysulfides on a newly synthesized material named two-dimensional conjugated aromatic polymers (2D-CAP) was investigated using density functional theory calculations. The results show that the surface of 2D-CAP can provide moderate adsorption energies towards the soluble polysulfides, which can effectively avoid the dissolution of polysulfides into electrolyte while preserving their structural integrity. In the meantime, the small bandgap of 2D-CAP disappeared after lithium polysulfides adsorption and the nanoporous structure of 2D-CAP can facilitate lithium ion transportation, which can improve the cycling performance of Li-S batteries. Moreover, the 2D-CAP can effectively catalyze the decomposition process of Li 2 S. All of these properties suggest that 2D-CAP is a prospective anchoring material for lithium-sulfur batteries which not only mediate the shuttle effect of soluble polysulfides but also promote the charge reaction of sulfur cathode. [Display omitted] • 2D-CAP provides moderate adsorption energies towards soluble polysulphides. • Pyridinic-N atoms in 2D-CAP catalyze the decomposition process of Li 2 S. • The abundance of N atoms in 2D-CAP provide ample adsorption sites for polysulphides. • Li ions can migrate rapidly across the 2D-CAP surface as well as through the pores. • 2D-CAP is electrically conductive after adsorption of polysulphides. [ABSTRACT FROM AUTHOR]

• MoP nanoparticles in-situ grown on MWCNTs for enhanced hydrogen evolution reaction with a facile path. • Strong interconnections of MoP nanoparticles with the MWCNTs obtained by in-situ transformation of MoSx to MoP. • The morphology and distribution of MoP was tuned by Mo-C ratio for high active sites. • The MoP/MWCNTs with Mo-C ratio of 1/2 significantly enhance the HER performance. • MoP/MWCNTs -1/2 also exhibited excellent stability performance. [Display omitted] Molybdenum phosphides (MoP) have been demonstrated to be effective electrocatalysts for hydrogen evolution reaction (HER). The active sites of MoP particles and interface connections of MoP particles with carbon nanotube conducting networks are crucial to enhance their electrocatalytic performance. However, it is a big challenge to control the active sites of MoP and the interconnections between active materials with conducting networks. An in-situ method to fabricate MoP nanoparticles on multi-walled carbon nanotubes (MWCNTs) has been investigated to give MoP/MWCNTs with high active sites of MoP nanoparticles and strong interconnections between MoP nanoparticles and conducting MWCNTs from in-situ grown molybdenum sulfide (MoS x) on MWCNTs (MoS x /MWCNTs) precursors. The MoS x on MWCNTs were directly converted into MoP nanoparticles with strong interconnections with the carbon nanotube conducting networks. The morphology and distribution of MoP were adjusted by changing the Mo-C ratio to obtain large amount of active sites. The MoP/MWCNTs with Mo-C ratio of 1/2 have been demonstrated to significantly enhance the HER performance. Overpotentials of 109 mV and 155 mV have been obtained at 10 mA cm-2 with corresponding small Tafel slope of 56.5 mV dec-1 and 56.8 mV dec-1 in acidic and alkaline solution, respectively. [ABSTRACT FROM AUTHOR]

Effective control of sulfate-reducing bacteria (SRB) will help reduce economic losses and prevent threats to human health during the oil production. In this study, the responses of SRB to environmental variables and some functional microorganisms (including denitrifying bacteria (DNB), methanogenic bacteria (MGB), saprophytic bacteria (SPB), zymophyte bacteria (ZPB), and iron bacteria (IB)), during oil production processes were investigated to improve our understanding of how to control SRB abundance. Correlation analyses demonstrated that nitrate and redox potential exihibited significant inhibitory effects on the growth and reproduction of SRB and redox potential (0.175, P < 0.01) had a stronger effect than NO 3 − (0.0817, P < 0.05). PCA analysis demonstrated a clear division of the bacteria into two clusters, cluster 1 consisted of SRB, SPB and IB, while cluster 2 consisted of DNB, MGB and ZPB. Cooperation was apparent for SRB with SPB and IB, while competition was apparent for SRB with DNB, MGB and ZPB. These results provide new insights to possible solutions to control SRB growth in the oilfield environment, including addition of nitrate and nitrite, to promote the growth of denitrifying bacteria, thereby suppressing the growth of SRB. • SRB exhibited a strong response to nitrate concentration and redox potential. • Higher nitrate concentration and redox potential strongly inhibited SRB growth. • SRB exhibited a cooperative relationship with SPB and IB in the oil production. • SRB had a competitive relationship with DNB, MGB and ZPB during oil production. [ABSTRACT FROM AUTHOR]

Highly efficient bluish white phosphors based on self-activated luminescent materials are essential part for fabricating white lighting diodes. Transition metals have a wide application in catalyst and photoluminescence aspects especially for molybdenum and tungsten, which multi-metal oxides also promote diverse properties. In this work, a serial of novel structural mixed phases phosphors LiCa 3 MgV 3-X W X O 12 (short as LCMV-W-X) combined with vanadate and tungsten oxides are constructed by sol-gel method for the first time. The photoluminescence quantum yield (PLQY) of LCMV-W-0.20 is significantly enhanced to 64.37% related to the decreasing of luminous centers distance and oxygen vacancies. The deeper reason for the significant enhancement in PLQY can be ascribed to the fact that the introduction of tungsten phase leads to the lattice deformation of [VO 4 ] and [WO 4 ] tetrahedron of LCMV-W-X, which increases the interaction of luminescence centers. At the same time, the luminescence characteristics of tungsten oxide make LCMV-W-X fluorescence performance change with the change of tungsten content. Hence, this work enlightens a new method to construct highly efficient phosphors. [Display omitted] •A series of novel LiCa 3 MgV 3-X W X O 12 phosphors are rationally constructed for the first time. •The photoluminescence quantum yield of LCMV was enhanced to 64.37% due to W-doping. •The introduction of tungsten strengthened the interaction between V5+ luminous center. •It shows the possibility of white light-emitting diode application as a tunable light source. [ABSTRACT FROM AUTHOR]