Electrically conductive nanowires controlled one pivotal route in energy harvest and microbial corrosion via direct metal-microbe electron transfer

Extracellular electron transfer(EET)plays a critical role in bioelectrochemical processes,allowing cou-pling between microorganisms and extracellular solid-state electrodes,metals,or other cells in energy metabolism.Previous studies have suggested a role for outer-surface c-type cytochromes in direct metal-to-microbe electron transfer by Geobacter sulfurreducens,a model electroactive bacterium.Here,we ex-amined the possibility of other microbially produced electrical contacts by deleting the gene for PilA,the protein monomer that G.sulfurreducens assembles into electrically conductive protein nanowires(e-pili).Deleting pilA gene inhibited electron extraction from pure iron and 316L stainless steel up to 31%and 81%,respectively more than deleting the gene for the outer-surface cytochrome OmcS.This PilA-deficient phenotype,and the observation that relatively thick biofilms(21.7μm)grew on the metal surfaces at multi-cell distances from the metal surfaces suggest that e-pili contributed significantly to microbial cor-rosion via direct metal-to-microbe electron transfer.These results have implications for the fundamental understanding of electron harvest via e-pili by electroactive microbes,their uses in bioenergy production,as well as in monitoring and mitigation of metal biocorrosion.

Fabrication of High-Haze Flexible Transparent Conductive PMMA Films Embedded with Silver Nanowires

High-haze flexible transparent conductive polymethyl methacrylate （PMMA） films embedded with silver nanowires （AgNWs） are fabricated by a low-cost and simple process. The volatilization rate of the solvent in PMMA solution affects the surface microstructures and morphologies, which results in different haze factors of the composite films. The areal mass density of AgNW shows a significant influence on the optical and electrical properties of composite films. The AgNW/PMMA transparent conductive films with the sheet resistance of 5.5Ω sq ^-1 exhibit an excellent performance with a high haze factor of 81.0% at 550？nm.

Ordered Nafion ionomers decorated polypyrrole nanowires for advanced electrochemical applications

Fabrication of novel electrode materials with ordered proton-migration channels is an effective strategy to enhance the proton conductivity of the electrode for polymer electrolyte membrane fuel cells. Here we report the electrochemical fabrication of ordered Nafion？ionomers decorated polypyrrole nanowires to construct the ordered proton-migration channels. Based on the electrostatic interaction between Nafion？ionomers and the polymer intermediate, ordered Nafion？ionomers decorated polypyrrole nanowires could be fabricated via chronoamperometry with varying contents of Nafionionomers. The morphologies, charge-storage performances, electron conductivity and proton conductivity of the composites are investigated by scanning electron microscopy, cyclic-voltammetry, galvanostatic charge–discharge measurement and electrochemical impedance spectroscopy. With the modification effect of Nafionionomers on polypyrrole nanowires, the composite shows greater ordered structure relative to another without Nafion？ionomers and the electrochemical performances change with the content of Nafion？ionomers.The composite could achieve a high specific capacitance of 356 F/g at 1 A/g with a 0.62-fold enhancement compared to polypyrrole nanowires without Nafion？ionomers. It also displays a superior electrical conductivity of 49 S/cm and a quite high proton conductivity of 0.014 S/cm at working conditions of fuel cells, which are associated with the requirements of fuel cells and have the potential to be the electrode material for a large range of electrochemical energy conversion devices.

Conductivity and mechanical properties of conductive adhesive with silver nanowires

The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of silver nanowires/flakes on the conductive adhesive＇s electrical and mechanical properties was investigated. Compared with conventional conductive adhesive with silver flakes fillers, the percolation threshold of conductive adhesive with silver nanowires fillers is 10 % lower approximately. However, further rise of the content of silver nanowires has no obvious influence on improvement of the electrical conductivity of conductive adhesive. Both conductive and mechanical properties of conductive adhesive can be compatible by adding silver nanowires, which traditional silver conductive adhesives cannot reach.

Improvement of the Conductivity of Silver Nanowire Film by Adding Silver Nano-Particles

The change of conductivity and transparency of silver nanowire （AgNW） films by adding silver nano-particles （AgNPs） onto their surface is studied. The results show that the conductivity of the AgNW film is greatly improved with its sheet resistance reduced about 78. 7% to 51.9Ω/sq, and there is no obvious reduction of the transmittance. Further studies show that there is a self-assembling process pushing the AgNPs to concentrate at the intersecting points between AgNWs to weld them, which would reduce the intersection resistance between the AgNWs. This self-assembling behavior is led by the surface interactivities among the dispersing liquid of AgNPs, the surface of the substrate and AgNWs when the dispersing liquid is drying.

Temperature dependence of heat conduction coefficient in nanotube/nanowire networks

Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional（1D） and twodimensional（2D） lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.

Conductive proteins-based extracellular electron transfer of electroactive microorganisms

Electroactive microorganisms(EAMs)could utilize extracellular electron transfer(EET)pathways to exchange electrons and energy with their external surroundings.Conductive cytochrome proteins and nanowires play crucial roles in controlling electron transfer rate from cytosol to extracellular electrode.Many previous studies elucidated how the c-type cytochrome proteins and conductive nanowires are synthesized,assembled,and engineered to manipulate the EET rate,and quantified the kinetic processes of electron generation and EET.Here,we firstly overview the electron transfer pathways of EAMs and quantify the kinetic parameters that dictating intracellular electron production and EET.Secondly,we systematically review the structure,conductivity mechanisms,and engineering strategies to manipulate conductive cytochromes and nanowire in EAMs.Lastly,we outlook potential directions for future research in cytochromes and conductive nanowires for enhanced electron transfer.This article reviews the quantitative kinetics of intracellular electron production and EET,and the contribution of engineered c-type cytochromes and conductive nanowire in enhancing the EET rate,which lay the foundation for enhancing electron transfer capacity of EAMs.

Fabrication of Flexible Transparent Conductive Films with Silver Nanowire by Vacuum Filtration and PET Mold Transfer

The flexible transparent conductive films （FrCFs） of silver nanowire-polyethylene terephthalate （AgNW- PET） were prepared by a facile method including vacuum filtration and mold transferring. The effect of silver nanowire weight density on the optical and electrical properties of films, as well as the electrical percolation was investigated. The obtained typical AgNW-PET film exhibited high figure of merit of 31.3 × 10^-3 Ω^-1 with low sheet resistance of 4.95 D sq^-1 and high transparency at 550 nm of 83.0% （excluding PET substrate）. The resulting FTCFs based on PET substrate with high transmittance and low sheet resistance have a great potential in the application of high-performance flexible electronics and photovoltaic devices.

Scaffold-regulation buffered MoS_(2)anode kinetics for high-performance Na-/K-ion storage

Designing a highly conductive scaffold with unique function has great significance in elevating the stor-age properties of molybdenum sulfide(MoS_(2))for sodium-and potassium-ion batteries.Herein,we show that forming a three-dimensional(3D)highly conductive dual backbone that consists of titanium nitride nanowires(TiN)coated on 3D carbon fiber(CF)could suppress the poor conductivity of MoS_(2).Theo-retical calculations predict that both TiN and CF boost the electronic conductivity,while the MoS_(2)will promote high ionic adsorption owing to the suitable adsorption energy.The as-prepared CF@TiN/MoS_(2),with mass loading up to 12.5 mg cm^(−2),achieves a high areal capacity of up to 5.40 mAh cm^(−2)under the current density of 0.6 mA cm^(−2)for sodium storage.The excellent performance of the hybrid can be attributed to buffer and conductivity enhancer features,allowing Na-ion to directly have contact with the CF@TiN/MoS_(2)hybrid.A series of electrochemical analyses including cyclic voltammetry and symmetric cell analyses affirm the significant improvement in transport kinetics.More importantly,the CF@TiN/MoS_(2)also achieves a high areal capacity of 3.29 mAh cm^(−2)under the current density of 0.3 mA cm^(−2)as anode material for potassium ion batteries(PIBs),demonstrating that the scaffold-regulated strategy is a feasible strategy to enhance the kinetics of MoS_(2)-based anodes for secondary-ion batteries and beyond.