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Silver nanowires find use in a myriad of applications, including communication systems, sensors, medical devices and electrical equipment. Temperature-dependent electrical and thermal properties of chemically derived silver nanowires are rarely explored. In the present work, seed-mediated synthesis of silver nanowires has been carried out, and their electrical and thermal conductivity at 300 K is found to be 1.848 × 107 S/m and 64.8 W/mK, respectively. A screen-printable ink of silver nanowires is formulated and printed on low-cost and widely used substrates like paper and cotton fabrics. Flexible printed electrodes could be made possible with uniform printed structures obtained in cotton fabric and paper substrate. The printed pattern exhibited sheet resistance of 0.7 Ω/sq. Screen-printed silver nanowires on paper show shielding efficiency of 99.9% in X band, which promotes them as excellent candidates in fabricating lightweight electronic devices by a one-step printing process. [ABSTRACT FROM AUTHOR]

In this paper, the electrical response of a carbon black polylactic acid 3D printed polymer is characterised in detail by a combination of advanced experimental techniques at different scale lengths. The electrical properties as a function of the temperature become repeatable after the second heating cycle, exhibiting different trends as a function of the printing parameters. Joule heating and oven-heating techniques have been compared, showing the advantages of the Joule heating method to maintain electrical conductivity due to the lower thermal inertia. Small-Angle X-Ray Scattering has been employed to discern the underlying physics, showing the crucial role of crystallinity, filler dispersion and carbon black aggregates to form an effective segregated conductive network. This investigation provides guidelines to produce 3D-printed devices with a reliable electrical response and the governing equations to operate them with sufficient accuracy for engineering applications. [ABSTRACT FROM AUTHOR]

The trend toward miniaturized and highly integrated chip packaging has created a pressing need for lead-free solders with high strength, toughness, and conductivity. In this paper, we designed a scheme of Al2O3-modified nanomaterial-reinforced low silver Sn1.0Ag0.5Cu (SAC105) solder matrix. To begin with, a novel amorphous carbon and nickel core–shell structure plating modified on Al2O3 (C/Ni/Al2O3) were prepared by the electroless plating method. Then, the nano-C/Ni/Al2O3 particle as reinforcement phase was mixed into the matrix solder alloy by ultrasonic vibration stirring. Finally, the morphology and relationship between coated carbon, deposited nickel and original solder interface were analyzed. The microstructure and main properties of the modified solders were also investigated. The experimental results suggested that amorphous carbon and nickel film were prepared on the surface of Al2O3 by electroless plating method. The outer layer of nano-Al2O3 was coated with non-uniform thickness of nickel and carbon coatings. The mass percentage of amorphous carbon was about 3.50%. Adding C/Ni/Al2O3 (0–0.5%) into the SAC105 solder matrix resulted in a gradual increase in conductivity and wettability. The strength and toughness of the modified solder alloy improved as well with the adjunction of reinforced phase. The tensile fracture surface exhibited from a mixture of ductile and brittle, characterized by dimples and cleavage surface, to a purely ductile mode consisting mainly of dimples. [ABSTRACT FROM AUTHOR]

In the present paper, V2O5-TeO2 glass was prepared by the melt-quenching technique. Crystallization of glass with a vanadium content higher than 35%mol results in an increase in electrical conductivity by a few orders of magnitude and a decrease in activation energy from ~0.40 to ~0.12 eV. In this work, a critical review of existing charge transfer models was presented on the example of V2O5-TeO2 glass and glass–ceramics. Schnakenberg's and Friedman-Triberis' charge transfer models were found to be applicable to both glass and glass–ceramics. Optical phonon frequencies obtained from Schnakenberg's model are in agreement with FTIR studies. Values of activation energies obtained from the Schnakenberg model decrease after crystallization. Friedman-Triberis' model shows an increase in the density of states near the Fermi level from 1019 eV−1 cm−3 in glass, to 1021 eV−1 cm−3 in glass ceramics. Structural studies show that the main crystallizing phase is Te2V2O9 which occurs with the V2O5 shell in glasses with compositions 50–50%mol and 45–55%mol. It is concluded that crystallization results in the reduction of vanadium ions in the remaining glass matrix which leads to an increase in the V4+/V5+ ratio and therefore, an increase in electrical conductivity. [ABSTRACT FROM AUTHOR]

AA6101 Al alloy is widely used as a high-strength conductive aluminum alloy, and the contents and existence of Mg and Si can influence its electrical conductivity and mechanical properties obviously. In this paper, experiments were conducted to find the optimal Mg, Si additions and Mg/Si ratio and then combined with heat treatment to improve the EC and mechanical properties at the same time. Firstly, considering the proper Mg/Si ratio, two optimal Mg and Si additions were determined: Al–0.7Mg–0.5Si and Al–0.4Mg–0.7Si with EC of 51.5%IACS and 51.4%IACS, and through homogenization treatment, their EC improved to 57.0%IACS and 55.7%IACS, respectively. Then, appropriate Fe was added to further control Si to achieve the balance of EC and mechanical properties. Results showed that for AA6101 Al alloy the ideal Mg/Si mass ratio was 1.4 and high Mg and low Si can obtain good EC and mechanical properties. Besides, it can be found that at low Mg/Si ratio, the alloy conductivity takes longer to reach its peak hardness. So the best performance Al–0.7Mg–0.5Si–0.2Fe alloy was obtained within the range of AA6101 national standard. The EC of Al–0.7Mg–0.5Si–0.2Fe can reach 56.3%IACS, and hardness is 91.3 Hv. Based on the study, a schematic diagram was drawn to analyze the influence mechanisms of Mg, Si and Fe on EC and hardness of AA6101 Al alloy. [ABSTRACT FROM AUTHOR]

Owing to the high demand for electronic devices and electric vehicles, a huge effort has been directed to the exploration and development of new batteries with good cycling stability, satisfactory high specific capacity and safety. In this paper, we report the designed synthesis of the vanadium oxide with mixed valence H2V3O8 and the composite H2V3O8/PEDOT:PSS using low cost and easy hydrothermal method. Electrochemical activity of the vanadium oxyhydroxide H2V3O8 and the composite H2V3O8/PEDOT:PSS as cathodes materials for high performance lithium–ion batteries was evaluated vs. Li+/Li at various current rates. Compared with pure H2V3O8, composite H2V3O8/PEDOT:PSS cathode exhibits higher specific capacity (390 mAh g−1 at 0.05 A g−1 whereas, an initial discharge capacity of 300 mAh g−1 is observed at 0.3 A g−1), more excellent rate performance and longer cycle life. The composite H2V3O8/PEDOT:PSS cathode delivers excellent specific capacity of ca. 390 mAh g−1 and a 97.5% capacity retention are achieved even after 350 cycles at current density of 0.05 A g−1. Higher electrochemical capacity and stability of the new composite cathode are mainly ascribed to a cooperative effect between the conductive polymer (PEDOT:PSS) with good electrical conductivity and the unique nano-sized H2V3O8 rods with short diffusion pathway for lithium ions diffusion. [ABSTRACT FROM AUTHOR]

Nanostructured transition metal phosphides (TMPs) have emerged as an attractive material in energy storage domains, owing to their high electrical conductivity and easy redox properties. However, the low actual specific capacitance and weak cycling stability hinder its further application. In this paper, the hierarchical nanosheet of CoP nanoparticles embedded in a two-dimensional carbon skeleton (Co-NP@C) with flake-like ZIF-67 as its precursor was synthesized by facile carbonization and phosphorization and employed as positive electrodes for asymmetric supercapacitors. Due to the presence of carbon skeleton and nanoparticles, a stable structure and more reaction channels for the electrochemical reactions were created, leading to a remarkable improvement of the electrical properties of Co-NP@C. The Co-NP@C electrode presents the exceptional electrochemical performance of 540 F g−1 at 1.0 A g−1. Furthermore, an asymmetric symmetric supercapacitor with Co-NP@C cathode and reduced graphene oxide (RGO) anode achieves superior cycling stability (92.4% after 10, 000 cycles at 10 A g−1) and a high energy density of 20.22 Wh kg−1 at a power density of 649.93 W kg−1. This study offers a simplified method for guiding the design of MOF-derived phosphide electrode materials and provides additional opportunities for optimizing high-efficiency supercapacitors. [ABSTRACT FROM AUTHOR]

The material choice for electrical contacts fundamentally governs the breaking performance, safety, and reliability of electrical switches. In recent years, amid a rapid escalation in infrastructure development, an upsurge in living standards, and advancements in scientific and technological realms, there has been a burgeoning demand for increased load capacity within power distribution systems, thereby imposing novel demands on electrical contact materials. The advent of two-dimensional graphene, with its exceptional electrical conductivity, thermal conductivity, and mechanical attributes, has piqued the interest of researchers in the electrical contact field. This has spurred further research and development into innovative graphene-enhanced electrical contact materials. This paper presents a comprehensive review of the progression made in graphene-enhanced silver-based electrical contact materials over the recent years. It particularly delves into the application of graphene in silver-based contact substances, encompassing the most recent developments in graphene-enhanced contacts, the underlying principles and processes governing arc generation and erosion, the arc-resistant mechanisms inherent to graphene-enhanced contact materials, and provides a forward-looking perspective on the potential future of graphene-based contact materials. [ABSTRACT FROM AUTHOR]

Calcium cobaltate (Ca3Co4O9) is an excellent thermoelectric (TE) material that can realize the mutual conversion between thermal and electrical energy based on the Seebeck effect. Compared with other ceramic TE materials, Ca3Co4O9 has the advantages of good oxidation resistance and high-temperature stability, but its electrical conductivity is low, making its TE properties insufficient. Thus, the figure of merit (ZT) of Ca3Co4O9 materials cannot meet the actual production needs, so it is necessary to modify the Ca3Co4O9 to improve its TE properties. By doping with other elements, the carrier concentration in the Ca3Co4O9 system will increase, and the phonon scattering by impurity atoms will occur, whereas the scattering of electron is rather weak. Thus, the electrical conductivity of the material increases and the thermal conductivity decreases. Therefore, the TE properties of the Ca3Co4O9 material will be improved. This paper summarizes the methods of doping with other elements to improve the TE properties of Ca3Co4O9 materials in recent years, mainly including Ca site doping, Co site doping, and Ca and Co site double doping with various elements, including alkali (earth) metals, transition metals, rare earth metals, and even main group metals and non-metals. Furthermore, the current problems and development trends of the doping modification of Ca3Co4O9 materials are discussed to provide a theoretical basis for the further development and utilization of Ca3Co4O9 TE materials. [ABSTRACT FROM AUTHOR]

Recently, thermoelectric (TE) devices have attracted much attention because they have no moving parts, simple structures, high reliability, and environmental friendly, when compared to other green energy techniques. In this paper, we report a novel thermoelectric composite constructed one with a self-assembled highly oriented Sb doped Bi2Te3 and one without doping nanoflake layer deposited on regular vertically aligned checkerboard-patterned multi-walled carbon nanotube (MWCNT) arrays (500 nm squares and 1 µm pitch) on insulated SiO2/Si substrates. The height of Bi2Te3/Bi0.4Sb1.6Te3, MWCNTs and volumetric ratio of MWCNT to Bi2Te3/ Bi0.4Sb1.6Te3 are about 3 μm, 1.5 μm, and 25%, respectively. The blending of regular vertically aligned MWCNT patterns into Bi0.4Sb1.6Te3 results in a dramatically enhancement of Seebeck coefficient and electrical conductivity. The Seebeck coefficient and power factor of Bi0.4Sb1.6Te3-MWCNTs show a maximum value of 600 μV/K and 60 μW/cm-K2 at 160 K and gradually decrease to 409 μV/K, and about 14.1 μW/cm-K2 at 300 K, respectively. The significant records of the low temperature Seebeck coefficients and relative electrical properties are extremely important for the fundamental understanding of vertically aligned MWCNT embedded thermoelectric composites. [ABSTRACT FROM AUTHOR]

This paper uses the scaleable and commercial in-situ (exhaust) dyeing method to fabricate reduced graphene oxide (rGO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) hybrids on knitted cotton fabrics to develop lightweight, flexible, and metal-free knitted cotton fabric for electromagnetic interference shielding (EMI SE) application. The graphene oxide (GO) and PEDOT: PSS solution were directly dyed and reduced through a green reducing agent C6H8O6 (L-ascorbic acid) at a low temperature (60 °C) by a commercially used exhaust dyeing process on cotton fabric. The morphology and elemental analysis, mechanical stability, hydrophobicity, electrical conductivity, and (EMI SE) performance rGO/PEDOT: PSS dyed fabric has been systematically studied. The electrical conductivity of the resultant composite fabric significantly improved up to 4.2 × 103 Scm−1 due to the higher inter bonding and adhesion of fibers in the yarn, and fabric assembly, with each fiber surface finely coated with composite of rGO and PEDOT: PSS with each other due to less interlayer spacing. The mechanical stability of tensile strength and hydrophobic performance of rGO/PEDOT:PSS composite dyed hybrid (RPD-1) significantly improved up to 49 MPa and 156°, respectively, due to an increase of graphene wt.%. The resultant cotton fabric exhibited outstanding EMI shielding performance up to − 49 dB on 30–1530 MHz and 39 dB on 8–18 GHz (X-band) frequency range which shielded almost 99.99% of incident electromagnetic radiation waves. [ABSTRACT FROM AUTHOR]

The inculcation of interlayer spacing sarchitectures between MXene (M-X) sheets is a simplified approach to inhibit restacking of Ti3C2Tx sheets and hinder this inclination. Hence, spacing architectural materials like conductive polymers (CP), carbon, and so on can undergo integration with Ti3C2Tx-M-X in order to benefit from their inherently electrical conductivity as well as elevated energy-storage disposition to attain a synergistic influence on enhanced electrochemical behavior. Furthermore, the intercalation of polymeric architectures into M-X layers presents another prospective pathway to expand the interlayering spacing between Ti3C2Tx-M-X, thereby further enhancing electrochemical capacitance as well as mechanical strength. Metallic oxides, susceptible to benefitting from wide oxidation states, can attain superior pseudocapacitance via redox reactions. Thus, energy-storage capacitance of Ti3C2Tx-M-X can be enhanced through the comingling with metallic oxides. Additionally, Ti3C2Tx-M-X layers restacking can be hindered through inculcation of transitional metallic oxides (TMOs) spacing architectures. Moreover, inclusion of conjugated polymers (CPs), serving as electrochemical materials, can hinder intercalation between Ti3C2Tx sheets. Therefore, this paper elucidates the effects of surface and interfaces on M-X and M-X polymeric nanoarchitectures properties and applications in energy storage devices and structures. [ABSTRACT FROM AUTHOR]

Transparent conductive oxides (TCOs) constitute a class of materials that combine high electrical conductivity and optical transparency. These features led to the development of the transparent electronics applications, such as flat panel displays, "smart" windows or functional glasses. N-type TCOs dominate the applications market, and the lack of a suitable p-type counterpart limits the fabrication of a completely transparent active device, which might be considered as a technological breakthrough. Among the wide range of p-type candidates, delafossite CuCrO2 (and its out-of-stoichiometry derivatives) is a promising material to achieve the desired p-type TCO properties as, up to date, it is presenting the foremost trade-off between optical and electrical properties. The present paper covers the research work and the major achievements related to copper chromium delafossite. A comprehensive overview of fabrication methods and opto-electronic properties is presented. The source of doping and the charge carriers transport mechanism are also thoroughly discussed. [ABSTRACT FROM AUTHOR]

As typical pseudocapacitive materials, manganese oxides have attracted great interest due to their high theoretical specific capacitance, abundant oxidation states and crystal structures. However, it is still struggling from inferior electrical conductivity, which comes from their natural properties and limited structure used. In this paper, we fabricate hierarchical mixed-valence manganese oxide/graphene on flexible carbon cloths via a hydrothermal method combined with annealing treatment strategy for improving capacitive performance. The microstructure and electrochemical performance of manganese oxide/reduced graphene oxide (MnOx/G) electrodes obtained at different annealing temperature (400–700 °C) are investigated. Evidenced by XRD, XPS and TEM, MnOx/G composites consisted of α-MnO2, hexagonal Mn2O3 and cubic MnO are achieved as the annealing temperature increased. The results reveal that the phase of MnOx, valence state of Mn as well as the pseudocapacitance can be regulated by varying the annealing temperature, and the mixed-valence state in the MnOx/G-400 composite boost pseudocapacitive property significantly. The MnOx/G-400 electrode yields the highest areal capacitance of 2.29 F cm−2 (437 F g−1) and remarkable stability compared to other MnOx-based electrodes, which is attributed to the favored electron transfer between Mn species (Mn4+ ↔ Mn3+), decreased charge transfer resistance and more active sites between different phase interfaces. This work reports the synthesis of hierarchical mixed-valence manganese oxide/reduced graphene oxide composites on flexible carbon cloths via a hydrothermal method combined with annealing treatment strategy for improving capacitive performance. [ABSTRACT FROM AUTHOR]

Research has shown half (Pr0.5Ba0.5MnO3-δ) perovskite to exhibit good electronic and magnetic properties. However, it is necessary to clarify whether electronic transport originates in the cubic or hexagonal phase. This paper explores Ba-doped Pr1-xBaxMnO3-δ (x = 0.35, 0.4, 0.45 and 0.5) disordered perovskites with mixed valence states. The cubic-phase transition increases when the EDTA sol–gel synthesis method was used. Electrical conductivity studies demonstrate that cubic P m 3 ¯ m space group symmetry with a little number of oxygen vacancies enhances conductivity. The origin of this process has been explained in terms of the transition from Mn4+ → Mn3+ ions forming hopping sites for electrons/holes. Rietveld refinement, HRTEM, and XPS confirm a complete structure transition to single cubic perovskite. Charge carrier transport clarifies that the cubic perovskite structure enhances the electrical conductivity more effectively than their cubic/hexagonal mixture counterparts. Our results suggest that the activation energy for electron transport is independent of symmetry but not of Pr3+ concentration. Electrical conductivity increases up to twice as much (182 Scm−1) suggested by previously published research, ratifying its potential application as a cathode for SOFC. [ABSTRACT FROM AUTHOR]

Stainless steel is considered to be the most potential bipolar plate material in hydrogen fuel cells due to its thin thickness and low cost, but suffers from decreased electrical conductivity in long-time usage. Herein, the surface of 316L stainless steel (SS316L) is modified by the ion implantation of Cr with different accelerating voltages and ion implantation doses. The implantation of Cr brings in a substantial improvement in the surface electrical conductivity, which is due to the formation of Cr oxide, Cr7C3 and Cr23C6. In all cases, interfacial contact resistance (ICR) is decreased with the increased implantation doses. In the cathodic environment, the minimum value of ICR (14.89 mΩ·cm2) is obtained at an accelerating voltage of 20 kV. However, in the anodic environment, the minimum value of ICR (7.19 mΩ·cm2) is obtained at an accelerating voltage of 40 kV. This is because the passive layer is destroyed by hydrogen. Besides, the deeper distribution of the Cr7C3 and Cr23C6 facilitates the formation of a more stable conductive pathway, which decreases the ICR. Moreover, simulations are also performed to give atomistic insights into the radiation damage during the implantation process. The results show that the maximum radiation damage is caused at an accelerating voltage of 40 kV. The unveiled mechanisms of the modified layer in this work are expected to guide the surface modification of stainless steel bipolar plates. [ABSTRACT FROM AUTHOR]

SnO2 anode material is considered to be a promising anode material for lithium-ion batteries owing to its high theoretical capacity. However, the application of SnO2 has been dramatically restricted because of pulverization led by the volume expansion during the charge/discharge process. To overcome these drawbacks, herein, SnO2 coated carbon nano tubes (CNT@SnO2) decorated graphene anode as free-standing and flexible was prepared and investigated for Li-ion anode application. The fine dispersion of SnO2 nanocrystals onto CNT surfaces and decoration of this structure between graphene layers not only suppresses the volume expansion but also effectively avoids aggregation of the SnO2, increases the specific surface area and active sites, and improves the electrical conductivity. The free-standing and flexible composite anode exhibit excellent reversible capacity, high Coulombic efficiency, and good capacity retention. [ABSTRACT FROM AUTHOR]

A new bifunctional nanomaterial, [SBCu(II)Hyd]-MWCNTs, exhibiting exotic electrical and magnetic properties has been synthesized via chemical modification of MWCNT-COOH. Double probe DC electrical conductivity, CV and EIS studies show better conductivity of the material than that of MWCNT-COOH. With higher saturation and remanent magnetization, as well as coercivity, [SBCu(II)Hyd]-MWCNTs showed better ferromagnetic characteristics. Mott–Schottky electrochemical analysis was carried out to explore capacitive and dielectric properties. The enhancement in electrical conductivity of [SBCu(II)Hyd]-MWCNTs is also confirmed by optical and electrochemical band gaps studies. Subsequently, this material has been utilized to fabricate an electrochemical sensor by coating it over glassy carbon electrode for the determination of glucose. The corresponding sensitivity and limit of detection values are calculated to be 1.1 µA µM−1 cm−2 and 0.09 µM, respectively. [ABSTRACT FROM AUTHOR]

Human epididymis protein 4 (HE4) is a highly sensitive and specific biomarker for diagnosing ovarian cancer. In this work, a new electrochemical aptasensor for rapid and sensitive detection of HE4 was constructed. Firstly, metal–organic framework/ketjen black (NH2-MIL-53(Al)/KB) composite with abundant amino groups and large specific surface area was prepared as signal amplifier to anchor gold nanoparticles (AuNPs). Subsequently, signal probe (SP) and a large amount of electroactive toluidine blue (Tb) were attached on AuNPs to form the tracer label, producing a distinct electrochemical detection signal. Moreover, Ni3(HITP)2 was modified by poly(diallyldimethylammonium chloride, PDDA) to obtain PDDA/Ni3(HITP)2, and then it was covered with deposited gold nanocrystals (DpAu) to form the sensing platform, which increased the electrical conductivity, specific surface area and the loading of triple-helix assembled probes (TAP). Target HE4 was bound to its aptamer in the outer layer of the TAP, leaving a separate capture probe (CP) on the electrode surface that can bind with the tracer label. The proposed aptasensor for HE4 detection showed a wide linear range from 1 to 10 nM with a detection limit of 0.41 fM. In addition, the aptasensor has good selectivity, stability and reproducibility. More importantly, this method showed satisfactory results in clinical serum sample analysis compared with ELISA, possessing application prospects in ovarian cancer diagnosis. [ABSTRACT FROM AUTHOR]

Electrical contact materials are a key core component of switching appliances. However, the arc-resistance, electrical conductivity and tribological properties of traditional contact materials should be improved for the electrical equipment in the new era. This work proposes a strategy to prepare a novel graphene/silver-based contact material by laser process. Nanosecond laser is applied to grow the graphene film on the surface of commercial AgSnO2 contacts. The optimal process conditions: the laser power is 4.8 W, scanning speed is 5 mm/s, and scanning times is 20. The resistance of graphene/silver-based contact is 0.1 mΩ, 53.7% better than that of the original contact The oxidation resistance is only 0.12%. The graphene/silver-based contact provides new perspective to produce high-end electrical contact materials. [ABSTRACT FROM AUTHOR]

There is an ever-increasing demand for polymer-based electrical leads patterned on polymer substrates of any shape to connect two electrical components. Much, however, still remains challenging about electrical leads made of polymer nanocomposites that have high affinity to polymer substrates and outstanding applicability to curved surfaces, unlike metals. This leads to the need for the development of photopatternable and electrically conductive polymer nanocomposites and, by extension, comprehensive understanding of the constituent and processes involved in their development. Here, a set of polymer nanocomposites incorporating exfoliated graphite nanoplatelet (xGnP) into SU-8, xGnP/SU-8 nanocomposites, are developed as photopatternable and electrically conductive nanocomposites for electrical lead micropatterning. The inclusion of xGnP, carbon-based conductive nanofiller, is intended to provide electrical conductivity, and the use of SU-8, photocurable host polymer, is designed to achieve both patternability and strong adhesion to polymer surfaces. First, the dependence of patterning characteristics (i.e., patterning thickness and patterning error) on xGnP content and UV exposure dose are extensively explored. The patterning thickness varies from 7.4 to 199.6 μm, and the patterning error changes from 12.1 to 32.7 μm with variations in xGnP content of 0.00–9.65 vol% and UV exposure dose of 500–5000 mJ/cm2. Next, an evolution in the electrical conductivity of xGnP/SU-8 nanocomposites with variation of xGnP content is explored to understand their electrical behavior. The electrical conductivity increases from 0.8 µS/m to 866.7 S/m with an increase in xGnP content of 0.00–9.65 vol%. Finally yet importantly, the applicability of xGnP/SU-8 nanocomposites to electrical lead micropatterning is demonstrated by photopatterning an electrical circuit for light-emitting diode chips using the xGnP/SU-8 nanocomposites on polydimethylsiloxane (PDMS) substrate. The findings of this study will contribute to a significant growth of polymer-based electrical leads and better understanding of photopatternable and electrically conductive nanocomposites. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are considered to be one of the most developed portable secondary battery systems for next-generation energy storage technologies due to their high theoretical capacity and environmental benignity. Nevertheless, the unpleasant "shuttle effect" of lithium polysulfides (LiPSs) and sluggish reaction kinetics during the charge–discharge process seriously hinder their pragmatic applications. Herein, we employ transition metal carbide (TaC) as the effective sulfur cathode material for high performance Li–S batteries, the powder is pulverized into nanoscale particles by rotation or vibration of the simple ball mill. After milling, TaC particles show a significant amount of surface defect and oxygen functional groups but no signs of oxidation. Ball-milling TaC has high specific surface area and electrocatalytic sites to suppress the shuttle of soluble LiPSs during cycling and provide effective chemical interaction, while the surface oxygen functional groups of the material ensure high electrical conductivity and the electrons/ions transfer of the electrode. Due to the above advantages, the S-BM-TaC electrode delivered a large discharge capacity reaching 1040.1 mAh g−1 at the initial cycle at 0.2 C and performed an excellent cycle stability of 729.1 mAh g−1 at 1 C after 500 cycles. The results show that ball milling TaC as a sulfur immobilizer for Li–S batteries is a high-performance design strategy. Above all, this work holds great promise for utilization in practically viable Li–S batteries. [ABSTRACT FROM AUTHOR]

A novel precipitation strengthening Cu–Fe–Zr alloy was designed and prepared based on the results of calculation of the phase diagram. After solid solutionizing, rolling and aging at 450 °C for 1 h, the alloy had a tensile strength of 515 MPa and an electrical conductivity of 72% IACS. There were two kinds of precipitates in the alloy after aging at 450 °C for 1 h. Fe precipitates with an average diameter of 4.3 nm were present in the deformed grains. Fe2Zr precipitates with an average diameter of 29.1 nm were present in the recrystallized grains. Both the Fe and Fe2Zr precipitates had coherent interfaces with the Cu matrix. The precipitation kinetics and effects on the properties of the alloy were discussed. It is found that the cold rolling enhanced the driving energy of precipitation. The precipitation of Fe and Fe2Zr had a dominant effect on the increase in electrical and mechanical properties of the alloy. [ABSTRACT FROM AUTHOR]

Transitional metal oxides have attracted increasing attention as the most promising anode material for lithium-ion batteries (LIBs). However, due to the poor ionic conductivity and great structural changes in the process of Li+ insertion and extraction, the performance of the pristine materials in batteries still has a far way to go to satisfy requirements. In this article, using spherical ZIF-12 as a pyrolysis precursor, two Co3O4 hollow core-shell carbon nanocomposites (CHS@C and CHS@CG) were fabricated via a molecular precursor pyrolysis strategy. The synergistic effect of the yolk-shell hollow nanosphere structure shortens the diffusion path of ions, increases the contact area between the electrode and electrolyte, and provides a buffer space for the volume change in the electrochemical reaction. Both materials have excellent structural stability and good electrical conductivity. In comparison, the performance of CHS@CG is better, and the reversible specific capacity reaches 831 mAh·g−1 at 0.2 C after 400 cycles. In the galvanostatic charge–discharge process, the Coulombic efficiency reaches nearly 100%, exhibiting a good reversible cycle. The synthesis method of these electrode materials can provide a reference for making other energy storage equipments. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate framework-8 (ZIF-8) is composed of Zn2+ ions chelated with four imidazolate rings, and its derivatives are actively investigated as promising anode materials for lithium-ion batteries (LIBs). Herein, ZIF-8 with a decahedral structure was coated with gelatin matrix possessing abundant carbon and nitrogen atoms (so-called ZIF-8@gelatin). The calcined ZIF-8 (N–ZnC) and ZIF-8@gelatin (N–ZnC@gelatin) at 700 °C under N2 flow exhibited the characteristic diffraction patterns of nitrogen-doped graphitic carbons. A simple gelatin coating improved the electrochemical performance of ZIF-8-based anode materials. When compared with gelatin-free analogue (N–ZnC), N–ZnC@gelatin exhibited the enhanced thermal stability, high surface area, and improved electrical conductivity. At a current density of 0.1 Ag−1 after 100 cycles, N–ZnC@gelatin delivered a high reversible capacity of 600 mAhg−1, whereas N–ZnC exhibited a relatively low capacity of 450 mAhg−1. At a high current density of 1.0 Ag−1, N–ZnC@gelatin maintained a high reversible capacity of 400 mAhg−1 even after 450 cycles, because of the enhanced structural stability and electrochemical properties that were attributed to incorporation of gelatin matrix. [ABSTRACT FROM AUTHOR]

Hierarchical organization and structuring in multi-scale of natural materials and their derived products tune their mechanical behavior, chemical resistance, transport of fluids, heat and charges, among other characteristics explored for diverse human technological needs. Biocarbons obtained through pyrolysis of woody biomasses have found application in environmental and agricultural technologies, and more recently on electrical and electrochemical devices. By means of an integrated approach of advanced experimental and computational techniques, this work has stepped further on the fundamental knowledge to unveil the influence of wood cellulose hierarchical structuring on the structural, chemical, and electrical properties of the formed pyrolytic carbonaceous materials at multi-scale. It was not solely found that pyrolysis temperatures increase improves biocarbons graphitization degree and their electrical conductivity, but also that formed graphitic carbons have a preferential crystallographic orientation. The latter is induced by the pristine cellulose fibers organization in wood which resulted in electrical conductivity anisotropy up to three times. The formation of nanopores takes part at higher pyrolysis temperatures due to carbonaceous material backbone degradation preventing increase in the electrical conductivity by graphitization and diminishing the electrical conductivity anisotropy as electrons paths lengths get more similar. [ABSTRACT FROM AUTHOR]

The φ16 mm single-crystal copper rod billet was prepared by the heated mold horizontal continuous casting process. After cold drawing + 600 °C× 5 s annealing to φ1 mm, the annealed φ1 mm single-crystal copper processing wire was cold drawn to φ0.2 mm (φ1 mm → φ0.2 mm), and the electrical conductivity, tensile strength and microstructure evolution of single-crystal copper wire were compared and analyzed. The research shows that the conductivity of the as-cast single-crystal copper rod is 102.1% IACS, the tensile strength is 141 MPa, the conductivity is as high as 97.26% IACS, after cold drawing to φ0.2 mm, and the tensile strength is greatly increased to 506 MPa. Compared with the as-cast properties, the electrical conductivity of the as-drawn wire is only reduced by 4.7%, while the tensile strength is increased by 258.9%. The as-cast rod exhibits typical characteristics of single-crystal copper; with the increasing amount of deformation, the microstructure evolves in the following form: dislocations generated by slip entanglement into dislocation cells → microstrip structure → layered structure → twin structure. A prediction model for the strength and electrical conductivity of single-crystal copper wire was constructed. The results show that grain refinement strengthening and dislocation strengthening are the key factors affecting the strength and conductivity of single-crystal copper wire, when deformed to φ0.2 mm, and twinning strengthening is superimposed in the above strengthening mechanism. [ABSTRACT FROM AUTHOR]

An original model is advanced for conductivity of polymer graphene composites by tunneling effect and interphase piece. The conduction and volume share of networked interphase are defined and considered. Besides, the properties of tunnels such as tunneling length, tunneling resistivity and contact diameter are supposed, which affect the percolation beginning and conductivity. Consequently, the novel model approximates the nanocomposite's conductivity by the properties of graphene, tunnels and interphase. The impressions of all factors on the conductivity are evaluated and justified. Furthermore, the model's forecasts are matched to the experimented facts of some examples. The conduction and diameter of graphene directly affect the conductivity. Additionally, the suggested model shows the positive characters of big interphase and narrow tunnels in the conductivity, despite the fact that narrow interphase and large tunnels cause an insulated nanocomposite. The outputs of novel model display good matching with the experimented facts. These evidences confirm the correctness of the suggested model, which can replace the conventional models in future studies. The developed model can optimize the breast cancer sensors, because the conductivity is an important term for detection. [ABSTRACT FROM AUTHOR]

Various morphologies of polyaniline (PANI) nanostructures (i.e., nanospheres, nanofibers, vertical nanowires, and cauliflower-like) were synthesized on the surface of reduced graphene oxide (RGO)/cotton fabric (CF) electrode through in situ chemical polymerization method. The synthesis parameters, such as oxidant/monomer (O/M) molar ratio and oxidant type, were changed to investigate the effect of surface morphology on supercapacitive performance of PANI/RGO/CF electrode. Also, the effect of the de-doping process of doped PANI on the electrochemical performance of the PANI/RGO/CF electrode was evaluated. It was found that the O/M ratio and oxidant type strongly affect the nucleation rate of PANI nanostructures, leading to developing electrodes with different surface morphologies providing different electrical conductivities and energy storage performances. The de-doping process was found as an unfavorable treatment, yielding the decreased conductivity and capacitive performance of the PANI/RGO/CF electrode. The synthesized fully doped PANI on the surface of RGO/CF using ammonium persulfate as the oxidant at an O/M ratio of 0.5 created an electrode with the vertical PANI nanowires morphology providing the highest electrochemical performance. The all-solid-state flexible symmetric supercapacitor assembled using this electrode delivered a remarkable energy density of 35.9 Wh kg−1 (at a power density of 130.5 W kg−1) and retained 91.5% of initial specific capacitance after 1000 mechanical bending cycles. This supercapacitor possessed good rate capability and excellent cycling stability (97.3% retention after 1000 charge–discharge cycles). The findings of this research will lead to a better design of polyaniline-based textile electrodes for the next-generation wearable supercapacitors. [ABSTRACT FROM AUTHOR]

Double-perovskite materials La1−xPrxBaCo2O5+δ (LPBCO), suitable for the application of intermediate-temperature solid oxide fuel cell (IT-SOFC) and other electrochemical devices, were successfully prepared through solid-state reaction method. The effects of La and Pr doping ratios on the crystallographic structure, thermochemical stability, thermal expansion, electrical conductivity, and electrochemical polarizations were analyzed and discussed. The X-ray diffraction results show that the crystal structure changes from single perovskite to double perovskite with the increase in Pr doping content. LPBCOs present excellent chemical stability with conventional electrolyte GDC at less than 1100 °C. The thermal expansion can be effectively reduced upon doping of Pr. The materials demonstrate high electrical conductivity even under relatively low temperatures, i.e., LP-73 (x = 0.3 with single perovskite) has the highest conductivity at 1680 S/cm at 400 °C. Among the double-perovskite compositions, LP-55 presents the highest performance in electrical conductivity though. Analysis of the electrochemical impedance spectra of LPBCOs symmetric cells reveals low area specific polarization resistances for these double-lanthanide-doped double-perovskite materials, and the charge transfer is determined as the dominating sub-process for the oxygen transport through the materials. All the findings show that La1−xPrxBaCo2O5+δ possesses excellent oxygen reduction activity and is promising for the application in IT-SOFCs. [ABSTRACT FROM AUTHOR]

The present study revealed the effect of combining one strong-inorganic and weak-organic protonic acid dopants on the electrical conductivity and electrochemical properties of flexible free-standing composite electrodes based on polyaniline and nanofibrillated cellulose (NFC) or its carboxylated analog (CNFC), synthesized using a bottom-up approach. Hydrochloric acid (HCl) served as a low molecular weight inorganic dopant while phytic acid (PhA) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAAMPSA) were chosen as the organic dopants. Both PhA and PAAMPSA acted as secondary dopants in the dually doped composites through the molecular conformation changes of PANI chains. Synergistic increase in the electrical conductivity is observed for dually doped PANI-NFC with the combination of PAAMPSA and HCl in comparison with PhA and HCl. Unlike the PhA, the morphological changes induced by PAAMPSA are more favorable for the enhancement of conductivity. Neither the morphological changes, nor the carboxylation of NFC affected the electrochemical properties of the composites as the specific capacitance values were influenced mainly by the type and the strength of the individual acids. The capacitance values per gram of the dually doped composite with PAAMPSA and HCl increased with the decrease in the NFC or CNFC loading reaching values above 200 F·g–1 measured at 50 mV·s−1 of composite for the 80 wt% PANI content. These results highlight the profound impacts of the secondary dopant in PANI on the performance of PANI-based nanocellulose composites. [ABSTRACT FROM AUTHOR]

Intelligent hydrogels are widely studied for their unique responsiveness, but single responsiveness limited the application of hydrogels. Compared with traditional electronic conducting hydrogels, ionic conducting hydrogels have good transparency, mechanical properties, and wear resistance, but the preparation of conductive hydrogels with stability, and multi-functional response is still a difficult challenge. This work reports a preparation strategy for the development of dual cross-linked poly(N-isopropylacrylamide-co-acrylic acid) P(NIPAM-co-AA) hydrogel through rapid photopolymerization. N,N′-methylenebis-acrylamide (BIS) is used as a cross-linking agent to form chemical cross-linking. At the same time, by introducing AA and Al3+ to form electrostatic and coordination interactions, the hydrogel has enhanced conductivity and exhibits adjustable low critical solution temperature behavior. The hydrogel achieved visual temperature response, enhanced mechanical properties, and stable electrical conductivity. The hydrogel can be applied to visual qualitative detection of the intelligent windows by using the high sensitivity temperature response characteristics. Stable high conductivity also motivates the design of thermo-sensitive sensor windows and visual detection materials. This study will promote the synthesis of hydrogels with multiple response capabilities and realize their applications in smart devices. [ABSTRACT FROM AUTHOR]

In principle, the conductivity mechanism of electrically conductive adhesives (ECAs) is described by percolation theory. However, no universal conclusion has been reached regarding this matter because these adhesives vary depending on the materials present between metal particles and the intimacy of metal-to-metal contact. In this work, the change in electrical resistivity during curing of silver particle-dispersed epoxy resin adhesives, which are commonly used as ECAs, was measured in situ to evaluate the effect of each component material of the adhesives on its electrical properties. The ECAs containing silver particles coated with different fatty acids exhibited different electrical resistivity changes during curing. Before curing, most of ECAs were not electrically conductive. The ECAs containing silver particles coated with hexanoic acid demonstrated an electrical resistivity of 4.0 × 10–3 Ωm before curing, exhibited a rapid decrease in electrical resistivity at low temperatures (100–140 °C), and achieved an electrical resistivity of 5.5 × 10–7 Ωm after curing. In addition, dipropylene glycol monomethyl ether acetate, the solvent contained in the conductive adhesive, reduced the contact resistance between silver particles. A high amount of the solvent in the ECAs resulted in a low electrical resistivity after curing. Furthermore, in this curing system, cure shrinkage was a minor factor affecting the electrical conductivity. Our study revealed that the thin fatty acid layer provided insulating properties to the silver surface. During curing, the fatty acids were removed from the particle surface via evaporation, and the electrical resistivity of the conductive adhesives decreased considerably. [ABSTRACT FROM AUTHOR]

Single-phase La1-xSrxCoO3 (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.1) nanofibers were synthesized via electrospinning technique. Different characterization techniques were employed to characterize the electrospun nanofibers. SEM was used to observe the morphology and size of the electrospun nanofibers, and the diameter of all fabricated nanofibers was found in the nanometer (nm) range. The XRD patterns of all the samples after heat treatment at 600 °C confirm the single-phase formation of La1-xSrxCoO3 (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.1) nanofibers. The single phase of all the samples was also confirmed by FTIR spectroscopy and had good agreement with XRD results. All the fabricated samples' thermal behavior was studied using TG/DTA, and all samples showed thermal stability at ≤ 600 °C. The single-phase La1-xSrxCoO3 (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.1) nanofibers-based devices were fabricated on inter-digitated electrodes, and IV characteristics curves of all the fabricated devices show that La1-xSrxCoO3 (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.1) nanofibers exhibit semiconductor-like behavior. The electrical conductivity of all the samples was calculated and found to decrease with increasing concentration of Sr doping. In all samples, the dominant conduction mechanism is ohmic at low voltage, while space-charge-limited current is the dominant conduction mechanism at high voltage and low temperature. The Seebeck coefficient of all the fabricated devices was calculated and found to increase with increasing Sr concentration and temperature. [ABSTRACT FROM AUTHOR]

Novel composites of Al–graphene (0.1–0.3 wt%) have been prepared by powder metallurgical processing. Powder composites were prepared by planetary ball milling route in toluene medium by 5 h of milling under inert atmosphere. Then, optimized high density compacted samples (prepared at 120 MPa) were sintered at 550 °C for 5 h. Various characterization of composites was done by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy, energy-dispersive spectroscopy (EDS), transmission electron microscope, high-resolution transmission electron microscope (HRTEM), selected area diffraction pattern (SAED), micro-Raman spectroscopy, electrical conductivity, and microhardness to obtain an Al–graphene composite with improved microhardness and electrical conductivity. Graphene was found in bi-layer form in the typical sample aluminum–graphene (0.2 wt%) composite. Purity of samples confirmed from EDS analysis showing only peaks of Al and C. XRD, XPS, HRTEM, and SAED studies establish the successful formation of Al and graphene composite. The typical aluminum–graphene (0.2 wt%) sample show significantly higher electrical conductivity (59.2 × 106 S/m) and microhardness (165 ± 08 VHN) values than that of pure aluminum, which shows electrical conductivity and microhardness values of 38.0 × 106 S/m and 65 ± 05 VHN, respectively. The results further advance electrical as well as structural, industrial applications of aluminum. [ABSTRACT FROM AUTHOR]

Orthorhombic niobium pentoxide (T-Nb2O5) possesses an intercalation pseudocapacitive behavior, which is a promising candidate of high-rate anodes for Li-ion capacitors. However, its low electric conductivity hinders the realization of this property. In our study, niobium oxides/carbon composites were prepared by calcinating a niobium peroxo-PAA complex (NbPAA) precursor to improve the electric conductivity. It has been found that the calcination temperature played an important role on the chemical compositions of obtained composites. A reduction phenomenon of niobium oxides by carbon was observed at high temperatures. At the medium temperature of 900 °C, the sample was composed of T-Nb2O5, monoclinic Nb2O5 (M-Nb2O5), amorphous carbon and niobium dioxide (NbO2). Due to the high conductivity of carbon, semi-conductivity of NbO2, and high specific capacity of M-Nb2O5, this sample exhibits a good specific capacity of 142 mAh g−1 (0.25 C) and a high-rate capability (capacity retention of 33.1%, 0.25 C to 25 C). It could be used as one of high-rate anodes for Li-ion capacitors. [ABSTRACT FROM AUTHOR]

The quenching sensitivity of an Al–Zn–Mg–Cu alloy containing trace amounts of Sc and Zr is studied by interrupted quenching experiments. Electrical conductivity of the quenched samples and the hardness of the samples subjected to one-stage and two-stage aging, are measured to construct the time–temperature–transformation (TTT) curves and the time–temperature–property (TTP) curves. It is revealed that the quenching sensitivity of the alloy is mainly influenced by the precipitation of coarse η phases during slow quenching, which preferentially nucleate and grow at grain boundaries and at the Al3(Sc, Zr) dispersoids that are incoherent with the matrix. The quenching sensitivity increases with the size and quantity of the coarse η phases. The nose temperature is 290 °C for both TTT and TTP curves, where the phase transformation rate is the fastest and the quenching sensitivity is the highest. Compared to one-stage aged samples, two-stage aged samples exhibit lower quench sensitivity due to the reduced transformation rate from η′ phases to η phases after slow quenching. The quenching sensitive temperatures range from 206 to 358 °C for the one-stage aged samples and from 213 to 352 °C for the two-stage aged samples. Moreover, based on the simulated TTT and continuous cooling transformation curves, an optimized quenching process is proposed in the present work. [ABSTRACT FROM AUTHOR]

Despite its high electrical conductivity and large redox-active surface area, the widespread application of Ti3C2Tx MXene was still restricted by its sluggish kinetics with low capacity for lithium-ion storage. In this article, both density functional theory (DFT) calculations and experiments had demonstrated that sulfur decorating provided an alternative to improve the lithium storage performance of Ti3C2Tx, which played a series of roles in enlarging interlayer spacing, accelerating the lithium-ion diffusion as well as improving Li storage capacity. Consequently, the S-decorated Ti3C2Tx delivered a high reversible capacity of 167.8 mA h g−1 after 100 cycles at 0.5 A g−1, excellent rate capability (138.5 mA h g−1 at 1 A g−1 and 121.2 mA h g−1 at 2 A g−1) and robust long-term cycling stability with a reversible capacity of 166.3 mA h g−1 after 400 cycles at 0.5 A g−1. These findings revealed an important new strategy for further design and rational fabrication of MXenes for energy storage applications. The S-Ti3C2Tx material had a large interlayer spacing, which made it had excellent electrochemical performance in lithium battery applications, and the calculated results showed that it only had a diffusion barrier of 0.24eV. [ABSTRACT FROM AUTHOR]

Metal matrix nanocomposites (MMNCs) are gaining more and more interest because matrices and nanophases with heterogeneous characteristics could combine to provide unprecedented properties. Given the high concentration of free electrons in metallic systems, electrical conductivity is one of the most crucial design criteria in selecting suitable MMNCs. However, due to the intrinsic complexity of MMNC systems (e.g., changed interfacial characteristics), reliable and accurate determination of electrical conductivity in MMNCs faces a considerable challenge. Notably, there lacks fundamental guidance with suitable theories and models for MMNCs' electrical conductivity. To address these issues and provide a clear understanding of electrical properties in MMNCs, this review intends to provide a comprehensive angle to explain, design, and analyze their electrical properties, electronic features, and electron behavior after their 20-year prosperous development. First, the review connects theories, effects of various engineering factors, and electrical conductivity data in the representative systems to provide an omni-spectrum insight into MMNCs' electrical performance. Following this discussion, the generic trend of electrical conductivity in MMNCs has been clarified for the first time, and the future focus and directions of MMNCs' electrical behavior study have been proposed. Generally speaking, this review will mitigate the current inconsistencies in MMNCs' electrical conductivity research and help open up new chances of achieving and extending electrical and other essential functional applications with MMNCs. [ABSTRACT FROM AUTHOR]

Effects of Si and Sr on solidification microstructure and thermal conductivity of Al–Si binary alloys and Al–9Si–Sr ternary were investigated, respectively, with a special focus on the relationship between solidification microstructure and thermal conductivity. It was found that (i) in Al–Si binary alloys, with increasing Si content, α-Al grain size increases and then decreases when Si content is over 7 wt%, while the percentage of eutectic Si continuously increases, which significantly decreases the thermal conductivity and electrical conductivity, and (ii) in Al–9Si–Sr ternary alloys, the presence of Sr has no significant effect on α-Al grain, but effectively modifies eutectic Si and significantly improves the thermal and electrical conductivity. On this basis, two theoretical calculation models [the Maxwell model and the Hashin–Shtrikman (H–S) model] were used to elucidate the relationship between solidification microstructure and thermal conductivity. Compared with the Maxwell model, the H–S model fits better with the measured values. The obtained results are very helpful to the precise composition control during alloy design and recycling of Al–Si-based alloys with the aim to further improve the thermal conductivity of Al–Si-based alloys. [ABSTRACT FROM AUTHOR]

With the extensive use of high-power electronic appliances, polymer-based thermal insulation composites with excellent thermal properties are utilized in the field of heat management with the aim of improving heat dissipation. Due to the high thermal conductivity and good electrical insulation, boron nitride (BN) is rendered as a superior candidate material for thermally conductive fillers. However, the thermal conduction of the composites is inevitably hampered by the interfacial resistance between BN and the polymer matrix. In this work, BN surface was modified by dopamine hydrochloride (PDA) and phenyltrimethoxysilane to enhance its interface compatibility with the polymer matrix. Meanwhile, by applying pressure to the composites during processing, BN grains inside the composite were well aligned to the direction parallel to the heat flow, thereby improving the through-plane thermal conductivity. When the filler content is fixed at 31 vol%, the thermal conductivity of the phenyl silicone rubber (PVMQ)-based composite prepared from modified BN (mark as M-BN/PVMQ) reaches 1.642 W/(m·K), nearly equal to nine times the value for the pure PVMQ matrix (0.18 W/(m·K)). Furthermore, in a nitrogen atmosphere, the initial decomposition temperature (T5%) reaches 512 °C, 172 °C higher than that of pure PVMQ (340 °C). The improved thermal stability of the composites prepared from modified BN resulted from the enhanced interfacial effect, which was analyzed by thermogravimetric infrared gas mass spectrometry system (TG-IR-GC/MS). The high thermal conductivity and stability enable the M-BN/PVMQ composite a promising material for thermal management. [ABSTRACT FROM AUTHOR]

Two-dimensional tungsten disulfide (WS2) is a promising anode material for lithium-ion batteries. The further development of WS2 is restricted by the defects of electrical conductivity and structural stability. Here, a bimetallic sulfide/carbon composite WS2-X/CoS@C was prepared by a facile one-step MOFs-engaged method. The WS2/CoS heterojunctions and sulfur vacancies were introduced into the material, which improved the electronic/ionic diffusion kinetics of the composite. A large number of honeycomb carbon nanotubes were formed on the surface of the composite, which could effectively increase the specific surface area and enhance the conductivity of the composite. The WS2-X/CoS@C electrode exhibited excellent electrochemical performance used as an anode for lithium-ion battery. The initial discharge capacity of the WS2-X/CoS@C delivered 936 mAh/g at 100 mA/g and retained high discharge capacity of 600 mAh/g at 200 mA/g after the 100 cycles. [ABSTRACT FROM AUTHOR]

Nitrite is one of the most commonly measured indicators in environmental monitoring due to its detrimental effects on environmental safety and human health. It is vital to develop simple and sensitive nitrite detection strategy. In this study, the solution-gated transistor sensor based on electrochemically reduced graphene oxide (ERGO) as the channel of the device was designed and fabricated to realize the sensitive detection of nitrite, in which Au nanoparticles/reduced graphene oxide (AuNPs/RGO) nanocomposites were functionalized the gate electrode for non-enzymatic electrocatalytic oxidation of the nitrite. The sensing principle of the electrochemically reduced graphene transistor (ERGT) is attributed to the change of the effective gate voltage caused by the electro-oxidation of nitrite at the gate, thereby regulating the channel current. Due to the high electrical conductivity of ERGO and the superior electrocatalytic property of AuNPs/RGO nanocomposites, the as-prepared transistor sensor showed superior sensing performance toward nitrite detection, including low-detection limit (1 nM), ultra-wide detection range (1 nM–15 mM), good anti-interference ability and long-term stability (86.1% current response retention after 15 days). Nitrite in natural lake water has been accurately detected by our device to prove its practicability, suggesting that the ERGT sensor can be served as a new platform to realize the highly sensitive nitrite detection in environmental and food safety monitoring. The ERGO channel of electrochemical transistor sensor was prepared by a simple electrodeposition method, realizing the high sensitivity detection of nitrite. [ABSTRACT FROM AUTHOR]

Electrically conductive multiwalled carbon nanotube (MWNT)/polyamide 6 (PA 6) nanocomposite films with high mechanical strength were fabricated by blending modified MWNTs with PA 6 polymer. The surface functionalization of MWNTs, which were modified using ureidopyrimidinone (upy) and pyrene-upy through covalent and noncovalent methods, respectively, significantly contributed to the uniform dispersion of MWNTs in PA 6, improving the electrical and mechanical properties of its nanocomposite. Particularly, noncovalent functionalization using pyrene-upy-MWNTs was more effective in achieving high electrical conductivities than covalent functionalization using upy-MWNTs. Pyrene-upy-MWNT/PA 6 nanocomposites with the highest electrical conductivity of 4.18 Scm−1, tensile strength of 39 MPa, and Young's modulus of 911 MPa exhibited excellent electromagnetic interference (EMI) shielding effectiveness of 57.8 dB mm−1. These results suggest that the simple and effective preparation of MWNT/PA 6 nanocomposites using our noncovalent modification with pyrene-upy can provide benefits for application area required electrical conductivity and mechanical strength such as EMI shielding. [ABSTRACT FROM AUTHOR]

The designation of yolk–shell structure is possessing advantages such as more active sites available and hierarchical space for volume expansion in the practical electrochemical applications. However, 3D yolk–shell nanostructures, with overall sizes over 100 nm, are still considered to be a certain degree of difficulty. Herein, we present the synthesis of novel yolk–shell Co3O4 microspheres in situ derived from Co-BTC/ZIF precursor, which is further decorated with graphitic carbon quantum dots coating layer (designated as YS-Co3O4/CQD). As expected, the yolk–shell structure with hollow cavity and interior porosity provides numerous active sites for enhanced electrochemical kinetics and effectively alleviates the volume effect for structural integrity. Moreover, the introduction of CQDs-decorated layer further improved the ionic/electric conductivity and the structural stability of YS-Co3O4 microspheres. Thus, the YS-Co3O4/CQD anode displays a high reversible specific capacity of around 1027 mAh g−1 at 0.1 A g−1, good cyclic stability up to 300 cycles at 1.0 A g−1 and superior rate capacity of 672.7, 550.3, 399.9 and 282.8 mAh g−1 at 4.0, 6.0, 8.0 and 10.0 A g−1, respectively. 1. We synthesize Co-BTC/ZIF derivative YS-Co3O4 decorated with CQDs coating. 2. Specific yolk–shell structure endows composite with excellent cycling stability. 3. The CQDs coating layer contributes to fast lithium storage kinetics. 4. YS-Co3O4/CQD exhibits ultrahigh rate capacity and good cyclic stability for LIBs. [ABSTRACT FROM AUTHOR]

Silicon is getting much attention as the promising next-generation negative electrode materials for lithium-ion batteries with the advantages of abundance, high theoretical specific capacity and environmentally friendliness. In this work, a series of phosphorus (P)-doped silicon negative electrode materials (P-Si-34, P-Si-60 and P-Si-120) were obtained by a simple heat treatment method, which can maintain the original nanoparticle morphology. The P-Si-60 material shows excellent discharge specific capacity, rate performance and cycling performance. The discharge specific capacity after 50 cycles remains > 2000 mAh g−1 with a capacity retention rate of 74.3%. The excellent electrochemical properties of P-Si-60 material can be attributed to the phosphorus doping without destroying the original particle morphology and nanostructure and the higher intrinsic electric conductivity. It will bring new thoughts for the further application of silicon negative electrode materials. [ABSTRACT FROM AUTHOR]

The development of materials with efficient heat dissipation capabilities and remarkable mechanical properties is essential for high-power integrated electronic devices and flexible smart devices. Herein, a flexible cellulose nanofibers (CNF)/nanodiamond (ND)/MXene (CNM) composite film with typical nacre-like structure is fabricated using a facile vacuum-assisted filtration approach. The composite film exhibits high thermal conductivity of 17.43 W m−1 K−1 at the thickness of 21 μm, which enhances 663% compared with CNF film. This is mainly due to the bridging effect of ND and the favorable orientation of MXene nanosheets. In addition, nacre-like structure and strong hydrogen bonding between MXene and CNF endow satisfactory mechanical properties (89.14 ± 3.61 MPa). Moreover, it is worth to note that the film exhibits improved electrical insulation (1.63 × 106 Ω cm) on account of the intervene of the insulating ND block the conductive path formed by MXene. Therefore, the CNM composite films provide a feasible choice of thermal management components for high-power flexible devices. [ABSTRACT FROM AUTHOR]

The influence of a grain orientation and textured surfaces on the droplet evaporation and the graphene coating wettability is investigated. The study of the behavior of water droplets on graphene-coated substrates is important for the development of highly sensitive sensor technologies. The coating of the graphene layer with water leads to changes in charge concentration and electrical conductivity. To date, there are very few studies on the effect of substrate textures and wall heating on water droplets evaporation on a heated graphene coating. The contact angle depends on the ratio of several factors: textures, grain orientation and grain size. In the final stage of evaporation of a water droplet on a hot textured substrate with graphene, a jump in the contact line of the water droplet is observed. The contact angle abruptly increases almost two times. Molecular-dynamic modeling has shown that the wettability depends on the grains orientation and the annealing duration. The measured experimental value of the copper contact angle of 74–76° after annealing corresponds to the simulation results considering the direct proportionality between the contact angle and the amplitude of the first maximum of the density distributions of water molecules in the vicinity of a smooth copper surface. [ABSTRACT FROM AUTHOR]

The effects of carbon fiber additions on the electrical and thermoelectric performance in p-type CoSb3-based skutterudite are reported. A threefold enhancement in electrical conductivity is found. Two different explanations for the increased electrical conductivity are considered: Either carbon atoms enter the CoSb3 lattice as a dopant that makes it more and more conductive, or the increase in conductivity is due to electrical percolation of the carbon fibers in the composite. X-ray diffraction data show that the lattice parameter of the CoSb3 is not affected by the presence of the carbon fiber; however, adding carbon is associated with precipitation of 20 wt. % elemental Sb. DFT calculations show that the enthalpy of formation of a solid solution of carbon (interstitial or as a substitution for Sb) is slightly positive. This would be offset by an increased entropy contribution at higher temperatures, so the free energy change overall is likely to be favorable. All of the results support an explanation based on an improved electrical conductivity of a very dilute solid solution of C in CoSb3. The average thermoelectric parameters of the composite material, including heat conductivity, average composite Seebeck coefficient, Hall effect, carrier mobility, and carrier concentration, were influenced by the carbon addition. Unfortunately, the effects largely cancel each other so that the overall zT of the composite was not improved. [ABSTRACT FROM AUTHOR]

Graphene-based film with superior mechanical and conductive performance shows potential applications in the fields of environment and energy. The large-scale production of large graphene oxide (GO) sheets is of great significance to improve the properties of macroscopic films. Here, we show an efficient shear exfoliation method for producing GO with large size and high yield. The size control is based on a size-dependent shear exfoliation pattern, in which the shear rate (γ) required for exfoliation increases with initial size of graphite oxide flakes (L0) as power law. In this regard, the production of GO with lateral size of 14 μm and relative single-layer fraction of 80% is realized by optimizing γ and L0. Due to the more compact and oriented structure, the GO film prepared with large GO sheets (~ 14 μm) exhibits superior tensile strength (~ 168.2 MPa), Young's modulus (~ 8.2 GPa), and electrical conductivity (~ 231.2 S/cm) after HI reduction, which has been increased by 38.8%, 70.8%, and 46.8% than that of GO film prepared with small GO sheets (~ 3.4 μm), respectively. These findings will be of great value in optimizing size and yield of GO sheets and provide useful information to design shear exfoliation process. [ABSTRACT FROM AUTHOR]