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Summary The renewably powered electrochemical conversion of CO2 into fuels and chemicals offers a pathway to decarbonized industrial processes that are difficult to abate with electricity alone. Electrocatalytic activity, selectivity, reaction kinetics, and stability are critical factors for the development of electrochemical CO2 reduction technology. While the activity and selectivity of various electrocatalysts have been reported in a number of publications, the understanding of kinetic issues of mass and charge transport from a perspective of materials science and engineering is lacking. This work covers the critical role of the triple-phase boundary of CO2, protons, and electrons in CO2 conversion. Proton and electron conduction in electrocatalysts are discussed as composite materials and single-phase materials, respectively. Relatively established composite proton- and electron-conducting electrocatalysts (PECEs) are reviewed from state-of-the-art research, and suggestions are given for further potential improvement. In contrast, as the development of single-phase PECEs for electrochemical CO2 reduction is still nascent, perspectives for future development are proposed. Metal-organic framework materials are suggested and discussed as one of the ideal material candidates for single-phase PECEs with strategies to increase proton and electron conductivity.

Mixed ion–electron conductors have a wide range of important applications in devices relying on mixed ion–electron transport, mainly including conducting polymer composites and ceramics. Herein, we...

The crystal structure, electronic structure, and thermoelectric properties of a half-Heusler VFeSb (HH-VFeSb) compound are investigated. The HH-VFeSb compound is successfully synthesized by arc-mel...

Ambipolar polymer semiconductors are among the most ubiquitous semiconductors used for high mobility organic field-effect transistors. However, since ambipolar polymer semiconductors are capable of...

Nature uses proteins for a variety of functions, and among all others, their ability to form high-hierarchical structures as well as to mediate charges. We are inspired by these functions of proteins in nature and utilize proteins for the formation of large-scale conductive materials. We report here on a new family of conductive biopolymers using only sustainable and abundant proteins. We show that our new biopolymers have superior mechanical properties and ionic conductivity, which is due to their high water uptake and the presence of oxo-amino-acids. We further show that our biopolymers can be easily functionalized in different ways, thus enhancing their ionic conductivity, enabling electron conduction, and introducing optoelectronic properties. We currently use our polymers for making new biosensors. These polymers are environmentally friendly, biodegradable, biocompatible, and low-cost, and we foresee their integration in numerous applications from biomedical to energy applications

The construction and surface modification of three-dimensional (3D) graphene structures have been recognized as effective ways to prepare high-performance graphene-based composites in energy-related applications. Herein, on the basis of well-defined morphology and efficient electron conduction, the 3D highly-stable graphene hollow nanospheres have been synthesized by using sacrificial template method. The as-prepared 3D graphene nanospheres exhibit superior mechanical stability, electrochemical stability, and strong hydrophobicity, which may accelerate the emission of H2O in acidic medium-based ORR. Accordingly, the 3D highly-stable graphene nanospheres are used to confine tiny Pt nanoparticles (3D r-GO@Pt HNSs) for ORR in acidic medium, exhibiting superior activity with 4-electron-transfered pathway. Meanwhile, dramatically improved durability are achieved in terms of both ORR mass activity and electrochemically surface area compared to those of commercial Pt/C. Keywords: Sacrificial template method, 3D r-GO nanospheres, Highly-stable, Hollow structure, Oxygen reduction reaction

We present thermopower measurements on Yb( $$\hbox {Rh}_{1-x}\hbox {Co}_x$$ ) $$_2\hbox {Si}_2$$ . Upon cobalt substitution, the Kondo temperature is decreasing and the single large thermopower minimum observed for $$\hbox {YbRh}_2\hbox {Si}_2$$ splits into two minima. Simultaneously, the absolute thermopower values are strongly reduced due to a weaker exchange coupling between the 4f and the conduction electron states with increasing x. Pure $$\hbox {YbCo}_2\hbox {Si}_2$$ is considered a stable trivalent system. Nevertheless, we still observe two minima in the thermopower indicative of weak residual Kondo scattering. This is in line with results from photoemission spectroscopy revealing a tiny contribution from $$\hbox {Yb}^{2+}$$ . The value at the high-T minimum in S(T) is found to be proportional to the Sommerfeld coefficient for the whole series. This unexpected finding is discussed in relation to recent measurements of the valence and Fermi surface evolution with temperature.

In this work, we have prepared the carbon-LiNi1/3Co1/3Mn1/3O2 composite through a simple and cost-effective method at a relatively low temperature (i.e., 180 °C) via spray drying. Nitric acid-treated commercial Super P powder could be well dispersed among LiNi1/3Co1/3Mn1/3O2 particles, while untreated Super P powder is particularly difficult to be uniformly distributed. The obtained I(003)/I(104) of the treated Super P-LiNi1/3Co1/3Mn1/3O2, according to the X-ray diffraction pattern, is higher than 1.70, suggesting that the highly ordered structure of LiNi1/3Co1/3Mn1/3O2 is maintained after compositing via the proposed approach. The resulted cathode material shows superior rate capability and stability, delivering a specific capacity of 115.7 mAh g−1 even at 1.5 A g−1, and a capacity retention of 87.0% after 500 cycles. In contrast, pure LiNi1/3Co1/3Mn1/3O2 delivers only 57.4 mAh g−1 at 1.5 A g−1 and remains 35.2% after 500 cycles. Carbon-coated LiNi1/3Co1/3Mn1/3O2 prepared from the carbonization of sucrose delivers as high as 141.0 mAh g−1 at 0.1 A g−1, but remains only 47.5% after 100 cycles. The enhancement of rate capability and stability from the treated Super P-LiNi1/3Co1/3Mn1/3O2 is due to the facilitation of the electron conduction by introducing homogenously distributed carbon, and thanks to the well-maintained ordered structure of LiNi1/3Co1/3Mn1/3O2.

Electromagnetic properties of Fe 50 Co 50 /Cu hybrid granular composite materials containing flaky Fe 50 Co 50 particles and flaky Cu ones have been studied in the RF to microwave frequency range to realize the double negative (DNG) material. The electrical percolation along the dispersed Cu particle chains takes place at the critical Cu particle volume fraction φ c_Cu = 0.07; the σ ac value of composites with φ c_Cu and above was more than 10-1 S/cm. The negative permittivity caused by the low-frequency plasma oscillation of conduction electron in percolated Cu particle chains was observed above φ Cu = 0.08; the hybrid composites with φ Cu 0.08 are in the low-frequency plasmonic state. Meanwhile, the negative permeability due to the magnetic resonances was obtained above φ Cu = 0.10. Therefore, in the Fe 50 Co 50 /Cu flaky particle composites with φ Cu 0.10, the DNG characteristics were realized by the low-frequency plasma oscillation and magnetic resonances in the RF to microwave frequency range. In the Fe 50 Co 50 /Cu flaky particle composites, the DNG spectrum was observed at relatively low Cu particle content and the DNG frequency band becomes broad compared to the Fe 50 Co 50 /Cu hybrid composites containing spherical or arborized shape particles.

A sextuple ordered interpenetrated copper-naphthalenediimide network has been constructed by combining the features of porous metal-organic frameworks and π-conjugated supramolecular aggregation. The material exhibits intrinsic semiconductive features with narrow bandgap energy (1.2 eV) and outstanding electron transport. Theoretical calculations combined with experiments indicate that the high electron conduction may originate from π-d coupling and J-aggregation.

In this report, we demonstrate a bimetallic Co/Cu-embedded N-doped carbon structure for trifunctional catalysis of oxygen reduction, oxygen evolution and hydrogen evolution reactions in alkaline media. A hybrid catalyst synthesized through a metal-organic framework-based process (M-NC-CoCu) enables an active trifunctional catalysis due to its multi-faceted favorable characteristics. It is believed that a range of catalytically active sites are formed through the approach including well-dispersed tiny CuCo2O4 phases, a high concentration of pyridinic and graphitic N, and Cu-Ox, Cu-Nx and Co-Nx moieties. In addition, a high-surface-area morphology with a high concentration of sp2 bonding, which is beneficial for facilitated electron conduction, further contributes to the performance as an electrocatalyst.

We investigate multiphonon-electron coupling enhanced defect generation process and breakdown (BD) in middle-of-line (MOL) spacer dielectrics (Si 3 N 4 , SiBCN, and SiOCN). Rather than traditional Poole-Frenkel process, we report inelastic multiphonon assisted tunneling plays a key role in conduction process in these defective dielectrics in both initial and post-stress electron conduction. More importantly, we demonstrate defect generation process follows a universal process independent of thickness among these seemingly very different dielectrics. We show multiphonon-electron coupling is responsible for the enhanced defect generation rate due to high-energy electrons at the anode, thus triggering to specie-release induced BD.

In this review I summarize our attempts to prepare supramolecular assemblies from phthalocyanine dyes, the objective being to design functional materials that have specific properties, [Formula: see text] electron conduction. We explore several supramolecular methods to achieve phthalocyanine assembly, [Formula: see text] by attaching crown ethers to the phthalocyanine rings and combining these with alkali metal ions, by providing them with long aliphatic tails, and by using aided assembly techniques such as wetting-dewetting interactions on surfaces. Also, chirality has been applied as a tool to produce new self-assembled structures. In our studies we focus on the electron conducting properties of the molecular materials and on their use as alignment layers for the fabrication of liquid-crystal displays.