Copper Nanowires Research Articles

Confined growth of NiFe LDH with hierarchical structures on copper nanowires for long-term stable rechargeable Zn-air batteries

The sluggish oxygen evolution reaction (OER) and poor stability of oxygen electrocatalysts are main obstacles to the scale-up commercial application of rechargeable Zn-air battery. Herein, a three-dimensional (3D) multi-level architecture design is achieved by the confined growth of two-dimensional (2D) layer double hydroxides of nickel and iron (NiFe LDH) flakes on copper nanowires arrays (Cu NWs), which is epitaxially assembled on the surface of Cu foam (CF). The established Cu@Cu NW@LDH possesses stronger bonding strength between NiFe LDH and Cu NWs as well as Cu NWs and CF endowed by electroplating method. The introduction of Cu NWs not only provides abundant nucleation sites for the deposition of NiFe LDH flakes but also improves the electron conductivity of composite. The obtained Cu@Cu NW@LDH shows excellent OER catalytic activity with a potential of 1.44 V at a current density of 10 mA cm−2 and strong alkaline resistance properties in comparison with NiFe LDH on CF (Cu@LDH). As expected, the rechargeable zinc-air battery (ZAB) with Cu@Cu NW@LDH as air electrode delivers superior cycling stability (250 h at a current density of 10 mA cm−2). This work paves a new way to the design of 3D multi-level architecture catalysts for ZAB.

Surface modification of microencapsulated phase change materials with nanostructures for enhancement of their thermal conductivity

Microencapsulated phase change materials (MEPCMs) possess great potential as thermal energy storage materials for heating and cooling applications in industries. However, one important disadvantage of many MEPCMs is their low thermal conductivity. To enhance the thermal conductivity of PCMs, additives with high thermal conductivity are usually added into PCMs. However, these additives might not be mixed uniformly with the PCMs. Herein we report the first use of a polyurethane acrylic lacquer and hardener (PALH) as an adhesive to allow the additives to be uniformly coated on the surface of the shell of MEPCMs. A vacuum filtration assisted drop-casting method was employed to coat nano additives such as nano graphite, copper nanowires, titanium carbide and multi-walled carbon nanotubes (MWCNT) on the shell of commercial MEPCM (MPCM 28D) using PALH. MWCNT was found to be the most effective in improving the thermal conductivity of the MEPCM, giving an 87% increase when just 5 wt% of MWCNT was added. Field Emission Scanning Electron Microscope (FESEM) images confirm the successful uniform coating of MWCNT on the shell of MPCM 28D, while Differential Scanning Calorimeter (DSC) thermograms show that the phase change properties of MPCM 28D remain largely similar to the pre-coated MPCM 28D. Furthermore, thermal cycling tests indicate that MWCNT do not significantly affect the energy storage and release performance of MPCM 28D. These results indicate that coating MEPCMs with MWCNT can be a simple and effective method to improve their overall thermal conductivity without sacrificing its performance.

Nickel hydroxide armour promoted CoP nanowires for alkaline hydrogen evolution at large current density

The development of hydrogen evolution activity (HER) electrocatalyst that can run durably and efficiently under the large current density is of special significance but still challengeable for the massive production of hydrogen. Herein, a CoP/Ni(OH)2 nanowire catalysts grown on Co foam (CF) with a three-dimensional heterojunction structure has been successfully prepared by electrodepositing nickel hydroxide on the surface of cobalt phosphide. The prepared CoP/Ni(OH)2–15 min sample reveals a superior HER activity and stability. It merely requires ultralow overpotentials of 108 and 175 mV to 100 and 500 mA cm−2, respectively. In addition, the long-term stability test shows that the catalyst (CoP/Ni(OH)2–15 min) can operate stably for at least 70 h at 400 mA cm−2. Utilizing NiFe-LDH/IF with high OER activity, the NiFe-LDH/IF || CoP/Ni(OH)2–15 min catalyst system possesses the same outstanding performance for overall water splitting (OWS), which can accomplish ≈ 500 mA cm−2 at 1.74 V in 1 M KOH electrolyte. Moreover, the NiFe-LDH/IF || CoP/Ni(OH)2–15 min couple can work for more than 80 h at 500 mA cm−2, indicating its a great prospect in the area of electrolysis water. Such excellent catalytic performance is mainly attributed to the armor effect of Ni(OH)2, which can not only promote the rapid decomposition of water molecules, but also prevent the loss of phosphorus and enhance the synergistic effect of CoP and Ni(OH)2. This work can offer a significant reference for the design with high-performance and durable transition metal phosphide electrocatalysts.

Magnetic field-induced alignment of nickel-coated copper nanowires in epoxy composites for highly thermal conductivity with low filler loading

In this work, the large-scale produced copper nanowires (Cu NWs) were coated by nickel nanoparticles (Ni NPs) lay, i.e., Cu NWs@Ni. And under external magnetic field condition, Cu NWs@Ni as thermally conductive fillers were filled into epoxy (EP) resin to prepare the composites with high thermal conductivity (TC). The results showed that, when the magnetic field was 80 mT, Cu NWs@Ni (molar ratio of Cu:Ni = 10:5, and saturation magnetization (Ms) = 20.3 emu/g) can distribute in EP resin in an orderly manner along the direction of the magnetic field, endowing the composite with excellent TC at lower loading. Especially, when only 9 vol% Cu NWs@Ni was filled, the TC along the direction of the magnetic field can reach 2.90 W/mK, which was 12.81 times than that of neat EP resin. Even so, the composite still maintained outstanding insulation properties, namely, the volume resistivity and the dielectric strength were 1.79 × 1015 Ω cm and 12.88 kV/mm, respectively. In addition, compared to that of neat EP resin, the composite still possessed splendid heat stability and mechanical properties. For the above positive improvement, the corresponding mechanisms were also discussed in detail.

Copper Nanowires as Catalysts for CO Oxidation

Copper Nanowires as Catalysts for CO Oxidation

Preparation of thermally conductive but electrically insulated polypropylene containing copper nanowire

The ever-increasing demand for higher power density and smaller device size of modern electronics has led to urgent development of highly efficient thermal management material systems. In this work, thermally conductive polypropylene/copper nanowire (PP/CuNW) nanocomposites were successfully prepared by hexadecylamine ligand layer decoration of CuNW, followed by solution mixing with PP and coagulation precipitation. The compression molded PP/CuNW thin sheets exhibit a planar randomly distributed CuNW network. The in-plane and through-thickness thermal conductivity of PP/CuNW with 3 vol% CuNW reaches 1.04 and 0.50 W/mK, respectively. With decoration of the hexadecylamine ligand on CuNW, the PP/CuNW remains electrically insulative up to 1.5 vol% of CuNW loading. The present work provides an effective method for preparation of highly thermally conductive yet electrically insulated polymer nanocomposites for thermal management applications.

Efficient Hydrogen Generation and Total Nitrogen Removal for Urine Treatment in a Neutral Solution Based on a Self-Driving Nano Photoelectrocatalytic System.

Urine is the main source of nitrogen pollution, while urea is a hydrogen-enriched carrier that has been ignored. Decomposition of urea to H2 and N2 is of great significance. Unfortunately, direct urea oxidation suffers from sluggish kinetics, and needs strong alkaline condition. Herein, we developed a self-driving nano photoelectrocatalytic (PEC) system to efficiently produce hydrogen and remove total nitrogen (TN) for urine treatment under neutral pH conditions. TiO2/WO3 nanosheets were used as photoanode to generate chlorine radicals (Cl•) to convert urea-nitrogen to N2, which can promote hydrogen generation, due to the kinetic advantage of Cl−/Cl• cyclic catalysis. Copper nanowire electrodes (Cu NWs/CF) were employed as the cathode to produce hydrogen and simultaneously eliminate the over-oxidized nitrate-nitrogen. The self-driving was achieved based on a self-bias photoanode, consisting of confronted TiO2/WO3 nanosheets and a rear Si photovoltaic cell (Si PVC). The experiment results showed that hydrogen generation with Cl• is 2.03 times higher than in urine treatment without Cl•, generating hydrogen at 66.71 μmol h−1. At the same time, this system achieved a decomposition rate of 98.33% for urea in 2 h, with a reaction rate constant of 0.0359 min−1. The removal rate of total nitrogen and total organic carbon (TOC) reached 75.3% and 48.4% in 2 h, respectively. This study proposes an efficient and potential urine treatment and energy recovery method in neutral solution.

Transparent Air Filters with Active Thermal Sterilization.

The worldwide proliferation of COVID-19 poses the urgent need for sterilizable and transparent air filters to inhibit virus transmission while retaining ease of communication. Here, we introduce copper nanowires to fabricate transparent and self-sterilizable air filters. Copper nanowire air filter (CNAF) allowed visible light penetration, thereby can exhibit facial expressions, helpful for better communication. CNAF effectively captured particulate matter (PM) by mechanical and electrostatic filtration mechanisms. The temperature of CNAF could be controlled by Joule-heating up to 100 °C with thermal stability. CNAF successfully inhibited the growth of E. coli because of the oligodynamic effect of copper. With heat sterilization, the antibacterial efficiency against G. anodireducens was greatly improved up to 99.3% within 10 min. CNAF showed high reusability with stable filtration efficiency and thermal antibacterial efficacy after five repeated uses. Our result suggests an alternative form of active antimicrobial air filter in preparation for the current and future pandemic situations.

Lithium Metal Deposition and Stripping in Porous Hosts Coupled with Viscous Polymer Electrolytes

High energy density rechargeable batteries are desired to meet global goals of increased use of renewable energy and vehicle electrification. Higher energy densities can be achieved by replacing graphite anodes with metal anodes. Among metal anode materials, lithium metal anodes are promising due to their high theoretical capacity and low reduction potential. However, obstacles such as dendrite growth and continuous electrolyte decomposition need to be addressed for successful commercialization of rechargeable batteries with lithium metal anodes. It is widely reported that porous 3D lithium metal hosts can mitigate dendrite growth by accommodating lithium deposition uniformly within the hosts during cycling. Continuous electrolyte decomposition can also be mitigated by replacing liquid electrolytes with solvent-free electrolytes. We incorporate both strategies in this work to address the critical issues described above by demonstrating lithium deposition/stripping cycling on 3D electrode hosts with viscous polymer electrolytes. First, lithium metal deposition/stripping cycling within non-conductive and conductive hosts were compared, where zinc oxide (ZnO) coated polyacrylonitrile (PAN) nanofibers was used as the non-conductive lithium metal host and ZnO coated copper nanowires were prepared as the conductive lithium metal host. The non-conductive host showed successful cycling of 5 mAh/cm2(25 µm thickness) of lithium metal without short circuiting. Further, deposition/stripping cycling with viscous star polymers (polystyrene-co-poly(polyethylene glycol) methyl ether acrylate (PS-co-PPEGMA)) and a linear oligomer polyethylene glycol dimethyl ether (PEGDME) were compared. The effects of the physical and electrochemical properties of the polymer electrolytes on lithium deposition and interfacial impedance will be discussed.

Preparation of copper nanowires and thermal oxidation behaviour in dry oxygen

Copper (Cu) nanowires are a promising functional and structural material in electronics, optoelectronic devices and integrated circuits. The preparation and thermal stability of Cu nanowires are crucial for the functional realisation and performance stability of related devices. In this work, the authors particularly prepared Cu nanowires by a two-step approach and further studied the thermal oxidation behaviour of Cu nanowires in dry oxygen. It was found that the as-prepared Cu nanowires have a good (111)-oriented single crystal structure with a smooth and clean surface. With the increase of annealing temperature and time, the Cu nanowires were oxidised gradually in dry oxygen and the crystal phase of Cu nanowires underwent the evolution of Cu (111)→Cu2O (111)→CuO (−111)+(111). Furthermore, when the temperature was not higher than 400°C, the as-formed Cu2O and CuO layers or nanowires were slightly crystallised or nearly amorphous. However, when the temperature was higher than 400°C, the as-formed CuO nanowires were greatly crystallised. It was further observed that the oxidation of Cu nanowires arose from the wire surface and formed a non-dense, nearly amorphous layer of Cu2O nanoparticles therein. Such Cu2O layer on the surface of Cu nanowires greatly reduces optical transmittance.

Engineering a Copper@Polypyrrole Nanowire Network in the Near Field for Plasmon-Enhanced Solar Evaporation.

Harvesting solar energy for vapor generation is an appealing technology that enables substantial eco-friendly applications to overcome the long-standing global challenge of water and energy crisis. Nonetheless, an undesirable low light utilization efficiency and large heat losses impede their practical use. Here, we demonstrate a typical design paradigm capable of achieving superb nonconvective flow assisted water collecting rates of 2.09 kg/m2h under 1 sun irradiation with a high photothermal conversion efficiency of up to 97.6%. The high performance is ensured by an elaborately constructed coaxial copper@polypyrrole nanowire aerogel with surpassing photons acquisition and thermal localization capabilities. Using state-of-the-art micro-/nanoscale measurements and multiphysics calculations, we show that the metallic copper nanowire core can effectively excite surface plasmon resonance, which induces swift relaxation dynamics to achieve a highly efficient light-to-heat conversion process. A thin polypyrrole layer dramatically enhances broadband light absorption with minimized infrared radiation and low thermal conduction, leading to an impressive local heat concentration as high as 220 °C under 4 sun irradiation. Engineered empty space inside aerogel assembly of building blocks further facilitates large light penetration depth, smooth mass transfer, and robust mechanical capacity for synergistically boosting actual presentation. This work provides not only a rational design principle to create sophisticated solar-thermal materials but also critical information that complements insights about heat generation and temperature confinement in a scale-span system during strong light-matter interaction processes.

Folding-insensitive, flexible transparent conductive electrodes based on copper nanowires

Flexible transparent conductive electrodes (FTCEs) have received a great deal of attention for various applications due to their versatile ability. To demonstrate high-performance of FTCEs, numerous efforts have been focused on high conductivity, transparency and mechanical durability against bending. However, it is still a challenge for FTCEs to apply in foldable applications due to the degradation of electrical conductivity during folding. In this paper, high-performance FTCEs with folding-insensitivity are achieved by embedding copper nanowires (Cu NWs) into polymethyl methacrylate strategy via simple sol-gel transition. The prepared film demonstrates a very high transmittance of ~94 % with a low sheet resistance of 56.3 Ω/sq. In particular, excellent insensitivity conductivity are achieved with a bending radius of 2.5 μm and the resistance remains nearly to be constant after 1000 folding cycles with a bending radius of 50 μm. Moreover, the film shows a good stability to resist long-term storage and ultrasonication. Finally, flexible transparent heater is fabricated based on the FTCEs, the immediate response make it have a great promise to be used as defrost, antifog and (light emitting diode) LED devices. • Folding-insensitive FTCEs are prepared by sol-gel technology. • The conductivity enable to achieve excellent insensitivity to the folding. • The FTCE shows a good stability to resist long-term storage and ultrasonication. • The FTCE has very high transmittance of ~94 % with sheet resistance of 56.3 Ω/sq.

Copper nanowire embedded hypromellose: An antibacterial nanocomposite film

The present work reports a novel antibacterial nanocomposite film comprising of copper nanowire impregnated biocompatible hypromellose using polyethylene glycol as a plasticiser. Detailed physico-chemical characterization using X-ray diffraction, Fourier transform infrared spectroscopy, UV–Visible spectroscopy and electron microscopy shows uniform dispersion of copper nanowire in the polymer matrix without any apparent oxidation. The film is flexible and shows excellent antibacterial activity against both Gram positive and negative bacteria at 4.8 wt% nanowire loading with MIC values of 400 µg/mL and 500 µg/mL for E. coli and S. aureus respectively. Investigation into the antibacterial mechanism of the nanocomposite indicates multiple pathways including cellular membrane damage caused by released copper ions and reactive oxygen species generation in the microbial cell. Interestingly, the film showed good biocompatibility towards normal human dermal fibroblast at minimum bactericidal concentration (MBC). Compared to the copper nanoparticles reported earlier in vitro studies, this low cytotoxicity of copper nanowires is due to the slow dissolution rate of the film and production of lower amount of ROS producing Cu2+ ions. Thus, the study indicates a strong potential for copper nanowire-based composites films in broader biomedical and clinical applications.

Compressive properties and behavior of copper nanowires wrapped by carbon nanotube

Compressive properties and behavior of copper nanowires wrapped by carbon nanotube

Synthesis of red photoluminescent nickel doped self-assembled copper nanoclusters and their application in biothiol sensing

Copper nanoribbons (Cu NRs) and Ni-doped copper nanowires (Cu NWs) with red photoluminescent (PL) were prepared and employed for detection of biothiol. Using 4-(trifluoromethyl) thiophenol as both reducing agent and protecting ligand, the copper nanoclusters (Cu NCs) were synthesized and assembled to nanoribbons. And the Cu NCs were assembled to nanowires by adding nickel ion precursor in synthetic process. The Cu NWs with 3% Ni doping showed a 3-fold emission enhancement than Cu NRs, and the absolute quantum yield was obviously increased from 4.53% to 19.76%. The doped Ni induced Ni-Cu metallophilic interaction, which facilitated the radiative relaxation of excited electrons and furtherly resulted in stronger PL emitting. The morphologies, composition, electronic states, geometrical configuration and arrangement of Cu NCs in assembled architecture were studied by experimental and theoretical investigation. Moreover, the PL of Cu NCs assembly was sensitive to cysteine, homocysteine, and glutathione attributed to surface ligands exchange of Cu NCs through interaction between metal and sulfydryl group. Therefore, a rapid, sensitive, and selective sensing strategy for detection of biothiol was proposed. And the PL test strips based on Cu NCs assembly were fabricated for visual detection of biothiol. Finally, the practical application of sensing system and PL test strips were verified in fetal bovine serum samples spiked with cysteine and homocysteine.

Microenvironmental Feeding and Stabilization of C2H4 Intermediates by Iodide-Doped Copper Nanowire Arrays to Boost C2H6 Formation

Microenvironmental Feeding and Stabilization of C₂H₄ Intermediates by Iodide-Doped Copper Nanowire Arrays to Boost C₂H₆ Formation

High-performance flexible transparent conductive tape based on copper nanowires

Copper nanowires (CuNWs) have low cost and high conductivity and are prominent components to replace the cost rising indium tin oxide (ITO) transparent electrodes. However, the standard coating method of CuNWs resulting in transparent electrodes' adhesion, flexibility and thermal stability is inferior. In this paper, a highly transparent, conductive, and flexible tape is reported, the tape is obtained by transferring CuNWs to conventional transparent tape. We use the viscidity of the tape to protect the CuNWs from corrosion and mechanical damage and use the electroplating welding to reduce the junction resistance between CuNWs. The sheet resistance of the transparent conductive tapes obtained is ~20 Ω/sq with the transmittance of ~80%, at 550 nm wavelength. In addition, the thermochromic paint printed on the transparent conductive tape film is a remarkable heater application. • High-performance CuNWs based flexible transparent conductive tape are obtained. • The tapes show low sheet resistance ~20 Ω/sq with the transmittance of ~80%. • Anticorrosion and mechanical performances of CuNWs are enhanced significantly. • Flexible heater based on transparent conductive tape is prepared and demonstrated.

Cobalt phosphide nanowires as efficient near-infrared light-driven antibacterial agents with high stability and cytocompatibility

Rapid emergence of antibiotic-resistant bacteria has brought huge threat to global healthcare systems. Alternative strategies are urgently needed to fight against these superbugs. In this study, we synthesized a series of cobalt phosphide nanoarchitectures and characterized their physicochemical properties as well as their antibacterial activities. We found that all nanomaterials showed an impressive photothermal property as indicated by their strong near-infrared (NIR) absorption capacity. In particular, 1D-CoP nanowires exhibited the optimal photothermal efficiency due to their higher aspect ratio. Under NIR light illumination, the temperature of the 1D-CoP nanowires suspension was increased by 45.4 °C within 20 min. In contrast, the temperatures of 2D-CoP nanoplates and 3D-CoP nanocubes were increased by 25.5 °C and 26.9 °C, respectively. The growth of planktonic bacteria can be effectively inhibited by 99% within 30 min under NIR irradiation with the presence of 1D-CoP nanowires in suspension. In comparison, up to 60% of the bacteria could be killed when treated with 2D-CoP nanoplates and 3D-CoP nanocubes. Moreover, all nanomaterials displayed high cytocompatibility. This work emphasizes that the anisotropy plays an important role in governing the photothermal properties of NIR-driven materials. Furthermore, the application of CoP nanowires is a promising strategy to treat antibiotic-resistant bacteria.

Copper Nanowires for Transparent Electrodes: Properties, Challenges and Applications

Transparent electrodes are essential elements of devices bearing a screen or display, as well as solar cells, LEDs etc. To overcome the drawbacks presented by indium tin oxide, nanomaterials have been proposed for a long time as alternatives. Metal nanowires are particularly interesting for their high intrinsic electrical conductivity. Copper nanowires have attracted wide interest due to the low cost and high abundancy of the starting material. However, they are easily oxidized thus suitable strategies must be devised to prevent it. This review discusses the fundamental properties and challenges of copper nanowires, focusing on the efforts made to make them longer and thinner then the strategies to prevent oxidation and to join them in the network are presented. After that, mechanical properties are summarized and applications are presented, before conclusions and perspectives are finally given.

A Pyrite Iron Disulfide Cathode with a Copper Current Collector for High-Energy Reversible Magnesium-Ion Storage.

Owing to its low cost, high theoretical capacity, and environmentally friendly characteristics, pyrite FeS2 demonstrates promise as a cathode material for high-energy metal-anode-based rechargeable batteries. When it is used in a rechargeable magnesium battery (RMB), the electrode couple exhibits an extremely low theoretical volume change upon full discharge. However, its electrochemical Mg-ion storage is considerably hindered by slow reaction kinetics. In this study, a high-performance FeS2 cathode for RMBs using a copper current collector is reported, which is involved in cathode reactions via a reversible redox process between copper and cuprous sulfide. This phase transformation with the formation of copper nanowires during discharge activates the redox reactions of FeS2 via a two-step and four-electron Mg-ion transfer that dominates the cathode reactions. As a result, the as-prepared FeS2 nanomaterial cathode delivers a significantly enhanced reversible capacity of 679 mAh g-1 at 50mA g-1 . The corresponding energy density of 714Wh kg-1 is superior to those of all previously reported metal chalcogenide cathodes in RMBs or hybrid batteries using a Mg metal anode. Notably, the as-assembled FeS2 -Mg battery can operate over 1000 cycles with a good capacity retention at 400mA g-1 .