Three-dimensional Nanowire Research Articles

Free-standing medium-entropy porous needle-like FeCoCuNi phosphide nanowires-formed flower clusters/carbon fiber anode with high capacity and long durability for sodium-ion batteries

The drastic volume expansion and slow sodium-ion kinetics hinder the practical application of phosphides with high specific capacity and low discharge voltage in sodium-ion batteries (SIBs). Herein, we introduced entropy configuration into nanostructures and prepared a novel free-standing, three-dimensional, porous needle-like medium-entropy Fe, Co, Cu, Ni phosphide (ME-FCCNP) nanowires-formed flower clusters/carbon fiber cloth (CFC) anode (ME-FCCNP@CFC) for SIBs. The distorted lattices caused by medium-entropy configuration provide abundant sites for sodium-ion reactions and improve the electron transfer rate. The medium-entropy effects improve the mechanical stability, while the three-dimensional networks and porous needle-like nanowires provide sufficient space for the volume expansion. These combined properties enable the ME-FCCNP@CFC electrode to exhibit a high-rate capability of 170.8 mAh g−1 at 5.0 A g−1 and deliver a specific capacity of 325.8 mAh g−1 after 2000 cycles at 2.0 A g−1, far surpassing most of reported transition-metal phosphides. Moreover, the Na3V2(PO4)3 || ME-FCCNP@CFC full cell showcases a high-energy density of 256.8 Wh kg−1 and a long cycling life (267.8 mAh g−1 at 2.0 A g−1 with a capacity retention of 83.2 % after 1000 cycles). These results provide significantly promising implications for the anode design of SIBs by employing self-supporting and medium-entropy structures.

Significantly improved thermal conductivity of C/C composite by constructing 3D SiC nanowires network in carbon felt via vacuum thermal evaporation

Developing a nanoscale secondary thermal conduction network within carbon fiber performs is a challenging yet effective method to substantially enhance the thermal conductivity of C/C composites. In this study, a strategy for creating a three-dimensional (3D) SiC nanowires (SiCNWs) thermal conductivity network in carbon felts (CFs) was implemented using vacuum thermal evaporation technology to fabricate SiCNWs modified C/C composites (SiCNW–C/C). The growth mechanism of SiC nanowires within CFs and their impact on the microstructure and thermal conductivity of the C/C composite were thoroughly investigated. The findings indicate that a SiC nanowires thermal conduction network can be successfully established within carbon felts without catalysts by initiating nucleation sites and managing reaction pressure. An appropriate reaction pressure is crucial not only for the uniform growth of SiC nanowires but also as a key factor in modulating the content and microstructure of the SiC nanowires. SiC nanowires prepared at 150 Pa exhibit minimal structural defects and are evenly distributed throughout the carbon felts, markedly enhancing the thermal response rate of the felts. The thermal conductivity of these SiCNW-modified C/C composites, both parallel and perpendicular to the carbon fibers, increased to 173 W/m•K and 112 W/m•K, respectively, approximately tripling that of the pure C/C composite. The exceptional thermal management capabilities of SiCNW–C/C were empirically validated through simulated operational chips and finite element simulation. This work presents an effective approach for producing C/C composite with high thermal conductivity particularly through the thickness, offering promising applications in the thermal management of advanced electronics.

Surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface for stable lithium anodes

Lithium (Li) metal has become a research hotspot for anodes materials due to its ultra-high theoretical capacity and the lowest redox potential. However, the practical application of Li metal batteries is hampered by the formation of uncontrollable Li dendrites and the irreversible structural changes during long-term charge/discharge processes. Developing stable Li metal anode with uniform Li deposition is highly desirable. Herein, surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface was demonstrated for stable Li anodes. Free-standing three-dimensional (3D) nickel nanowires (NiNWs) current collector decorated with lithiophilic NiF2 nanosheets (NiNWs@NiF2) was constructed via a simple and scalable fluorination strategy. Theoretical and experimental analysis confirmed that the lithiophilic surface of NiF2 nanosheets could reduce the Li nucleation barrier, facilitating uniform Li ion deposition. The 3D conductive NiNWs network enabled fast electron transfer and mitigated volume changes during cycling. Additionally, a LiF-rich nanoscale solid electrolyte interface (SEI) layer formed between Li and the electrolyte significantly improved the interfacial stability. As a result, the as-assembled Li-NiNWs@NiF2 symmetrical cell provided a superior electrochemical performance, maintaining stability for 2500 h at 1.0 mA cm−2 and 900 h at 5.0 mA cm−2. Furthermore, the assembled Li-NiNWs@NiF2|| LiFePO4 (LFP) full cell demonstrated exceptional capacity retention of 93.9 % after 2000 cycles at a rate of 5C. Overall, the unique structure of NiNWs@NiF2 not only offers a straightforward method for designing a 3D lithiophilic host, but also provides the concept of interfacial engineering through the in-situ construction of an artificial LiF-rich nanoscale SEI layer.

Geometrical properties of three-dimensional crossed nanowire networks

Three-dimensional interconnected nanowire networks have recently attracted notable attention for the fabrication of new devices for energy harvesting/storage, sensing, catalysis, magnetic and spintronic applications, and for the design of new hardware neuromorphic computing architectures. However, the complex branching of these nanowire networks makes it challenging to investigate these 3D nanostructured systems theoretically. Here, we present a theoretical description and simulations of the geometric properties of these 3D interconnected nanowire networks with selected characteristics. Our analysis reveals that the nanowire segment length between two crossing zones follows an exponential distribution. This suggests that shorter nanowire segments have a more pronounced influence on the nanowire network properties compared to their longer counterparts. Moreover, our observations reveal a homogeneous distribution in the smallest distance between the cores of two crossing nanowires. The results are highly reproducible and unaffected by changes in the nanowire network characteristics. The density of crossing zones and interconnected nanowire segments is found to vary as the square of the nanowire density multiplied by their diameter, further multiplied by a factor dependent on the packing factor. Finally, densities of interconnected segments up to 1013cm−2 can be achieved for 22-µm-thick nanowire networks with high packing factors. This has important implications for neuromorphic computing applications, suggesting that the realization of 1014 interconnections, which corresponds to the approximate number of synaptic connections in the human brain, is achievable with a nanowire network of about 10cm2. Published by the American Physical Society 2024

Thermoelectric and magneto-transport characteristics of interconnected networks of ferromagnetic nanowires and nanotubes

Macroscopic-scale nanostructures, situated at the interface of nanostructures and bulk materials, hold significant promise in the realm of thermoelectric materials. Nanostructuring presents a compelling avenue for enhancing material thermoelectric performance as well as unlocking intriguing nanoscale phenomena, including spin-dependent thermoelectric effects. This is achieved while preserving high power output capabilities and ease of measurements related to the overall macroscopic dimensions. Within this framework, the recently developed three-dimensional interconnected nanowire and nanotube networks, integrated into a flexible polymer membrane, emerge as promising candidates for macroscopic nanostructures. The flexibility of these composites also paves the way for advances in the burgeoning field of flexible thermoelectrics. In this study, we demonstrate that the three-dimensional nanowire networks made of ferromagnetic metals maintain the intrinsic bulk thermoelectric power of their bulk constituent even for a diameter reduced to approximately 23 nm. Furthermore, we showcase the pioneering magneto-thermoelectric measurements of three-dimensional interconnected nickel nanotube networks. These macroscopic materials, comprising interconnected nanotubes, enable the development of large-area devices that exhibit efficient thermoelectric performance, while their nanoscale tubular structures provide distinctive magneto-transport properties. This research represents a significant step toward harnessing the potential of macroscopic nanostructured materials in the field of thermoelectrics.

Three-dimensional bound states of cylindrical quantum heterostructures with position-dependent mass carriers

We present a comprehensive spectral analysis of cylindrical quantum heterostructures by considering effective electronic carriers with position-dependent mass for five different kinetic-operator orderings. We obtain the bound energy eigenstates of particles in a three-dimensional cylindrical nanowire under a confining hyperbolic potential with both open and closed boundary conditions in the radial and the axial directions. In the present model we consider carriers with continuous mass distributions within the dot with abrupt mass discontinuities at the barriers, moving in a quantum dot that connects different substances. Continuity of mass and potential at the interfaces with the external layers result as a particular case. Our approach is mostly analytical and allows a precise comparison among von Roos ordering classes.

Three-dimensional porous AuNPs-decorated polyaniline array for ultrasensitive determination of trace Cd(II) and Pb(II) in drinking water

Herein, a three-dimensional porous nanomaterials AuNPs-decorated polyaniline nanowire arrays/carbon nanotube (Au-PANI-array@CNT) was constructed by modified dilute polymerization and redox reaction. The Au-PANI-array@CNT exhibited a larger specific surface area (50.03 m2 g−1) and abundant mesopores (average pore size: 19.6 nm), due to the vertical growth of PANI nanowire arrays on CNT. The Au-PANI-array@CNT composite with a three-dimensional interconnected porous structure exhibited abundant electroactive sites and high adsorption capacity, significantly enhancing the deposition and electrochemical reaction process of heavy metals. The AuNPs embedded on PANI nanowries can provide high catalytic activity and multidimensional electron transport channels, further improving the detection sensitivity. A sensing platform with ultra-high sensitivity (2091, 3890 μA μM−1 cm−2) and lower limit of detection (0.18, 0.15 nM) for Cd(II) and Pb(II) determination was developed based on the three-dimensional porous PANI composite. Furthermore, the sensing mechanism of Au-PANI-array@CNT with Cd(II) was explored by XPS and FTIR spectroscopy. The current response only decreased by 5% after being stored at room temperature for 2 months, indicating that the sensor has high reproducibility and stability. Finally, the analysis of drinking water samples verified the excellent practicability of the sensor for the simultaneous measurement of trace levels (nM) of Cd(II) and Pb(II).

An effective copper doping strategy of Co(OH)F cathode for producing hydrogen in microbial electrolytic cells

In this study, the effective Cu doping Co(OH)F catalyst with three-dimensional network nanowires is successfully prepared by the one-step in situ hydrothermal route for Microbial Electrolytic Cell (MEC) cathode to improve the overall hydrogen production rate. The results demonstrate that the optimized doping ratio Cu-Co(OH)F exhibits a high open three-dimensional network structure and a good electrochemical hydrogen evolution activity (Tafel slope is 52.0 mV dec−1). In addition, the MEC with Cu-Co(OH)F cathode exhibits an extremely high current density of 69.2 A m−2, hydrogen production rate of 214.5 ml H2 L−1 cycle−1, and coulombic efficiency of 80.75%, which significantly improved the activity compared with undoped one. The results of density functional theory (DFT) calculations confirm that the doping of copper could regulate the electron transport rate and the Gibbs free energy to accelerate the process of hydrogen evolution, thus resulting in excellent hydrogen production in MEC.

Metal seeding growth of three-dimensional perovskite nanowire forests for high-performance stretchable photodetectors

Metal halide perovskites have been ubiquitously utilized in both rigid and flexible optoelectronics with high performance. However, developing perovskites-based stretchable optoelectronics is highly challenging because perovskites are intrinsically not stretchable unlike some organic semiconductors. Here, for the first time, we devised a novel metal seeding growth method to obtain three-dimensional (3D) perovskite nanowire forests (NWFs) with excellent mechanical stretchability, akin to the seeding growth of grass in nature. Benefiting from their intrinsic stretchability, perovskite NWFs-based stretchable photodetectors have been demonstrated with excellent photodetection performance. Under 0% strain, the device dark current is as low as 0.18 nA cm-2 at − 2 V bias, contributing to an ultrahigh light-to-dark current ratio (Ilight/Idark) of 1.1 × 105 under 5.5 mW cm-2 illumination. The device also exhibits a high responsivity of 455.3 mA W-1 and specific detectivity of 8.69 × 1012 Jones. Meanwhile, under 80% strain conditions, the device have shown negligible performance drop, especially in the aspect of Ilight/Idark. Our work reports a novel growth process that leads to intriguing 3D perovskite nanostructures with unique mechanical flexibility and stretchability, in addition to high optoelectronic sensing performance. These appealing properties can find applications in high-performance stretchable and wearable optoelectronics in the future.

Conformal Passivation of Self-Cleanable, Flexible, and Transparent Polytetrafluoroethylene Thin Films on Two-Dimensional MXene and Three-Dimensional Ag Nanowire Composite Electrodes

Despite the excellent performance of MXene–Ag nanowire (MA) composite transparent conductive electrodes (TCEs), they rapidly and severely degrade in ambient and humid environments. To address this critical issue, we developed conformal polytetrafluoroethylene (PTFE) passivation thin films prepared using magnetron sputtering at room temperature. Compared to the PTFE passivated electrode, the nonpassivated bare MA-composite electrode exhibited a considerably increased sheet resistance, and the electrode flexibility and electromagnetic interference (EMI) shielding efficiency (SE) degraded rapidly over time because the moisture and impurities severely oxidized the MXene layer in the harsh testing environment. However, the MA-composite electrode with PTFE passivation shows constant sheet resistance, transmittance, flexibility, and EMI SE, even after the 85 °C–85% relative humidity (RH) test. Compared to the nonpassivated MA-electrode-based thin film heaters (TFHs), the PTFE-passivated MA-composite electrode-based TFHs exhibited improved stability and reliability, indicating that the sputtered PTFE film effectively prevented the moisture and impurity penetration of the MA-composite electrodes.

Three-dimensional nanowire networks fabricated by ion track nanotechnology and their applications

The existing and future accelerator facilities at GSI and FAIR offer unique opportunities for interdisciplinary research, especially for material science and nanotechnology. On their way through polymers, swift heavy ions with GeV energy deposit enormous energy densities along their trajectory, generating long nanoscopic damage trails known as ion tracks. Ion-track technology utilizes the small track size (few nm) combined with the extensive track length (up to 100 μm and more) to synthesize and control the geometry of high-aspect-ratio nanostructures such as tailored nanochannels and nanowires. In particular, electrodeposition and ion-track nanotechnology provide an excellent platform for developing unique 3D networks of nanowires with controlled dimensions, composition and crystallographic properties. Here, a summary of recent results obtained on the synthesis and characterization of stable 3D architectures of semiconductor and semimetal nanowires, and their implementation in the fields of photoelectrochemistry and thermoelectrics, is presented.

Three-dimensional nickel nanowires modified by amorphous Fe nanosheets as electrocatalysts for the oxygen evolution reaction.

The development of electrode materials with abundant active surface sites is important for large-scale hydrogen production by water electrolysis. In this study, Fe/Ni NWs/NF catalysts were prepared by hydrothermal and electrochemical deposition of iron nanosheets on nickel chain nanowires, initially grown on nickel foam. The synthesized Fe/Ni NWs/NF electrode possessed a 3D layered heterostructure and crystalline-amorphous interfaces, containing amorphous Fe nanosheets, which demonstrated excellent activity in the oxygen evolution reaction (OER). The newly prepared electrode material has a large specific surface area, and its electrocatalytic performance is characterized by a small Tafel slope and an oxygen evolution overpotential of 303 mV at 50 mA cm-2. The electrode was highly stable in alkaline media with no degradation observed after 40 h of continuous OER operation at 50 mA cm-2. The study demonstrates the significant promise of the Fe/Ni NWs/NF electrode material for large-scale hydrogen production by water electrolysis and provides a facile and low-cost approach for the preparation of highly active OER electrocatalysts.

Sustainable anti-frosting surface for efficient thermal transport

Inhibiting frost formation is of fundamental importance for many industrial applications, ranging from various infrastructures to thermal systems. Sustaining a frost-free surface without reducing heat transfer efficiency is a great challenge. We hereby propose a counterintuitive approach to achieve sustainable anti-frosting under high heat flux subcooled condensation by accelerating the nucleation-to-departure cycle of condensed liquid, demonstrated by manipulating initial nucleation and reducing thermal resistance using a three-dimensional nanowire network. High heat flux subcooled condensation is maintained without frost formation on the frost-free surface at a low surface temperature of −15°C for more than 5 h in humid air with a relative humidity of 75%. More than 10 times enhancement in the steady-state heat flux is obtained on the frost-free surface compared with the state-of-the-art low solid fraction non-wetting nanostructured surfaces. This passive frost-free surface may hold promise for increasing the efficiency of thermal systems while inspiring the design of frost-free surfaces.

Super-Stretchable and Self-Healing hydrogel with a Three-Dimensional silver nanowires network structure for wearable sensor and electromagnetic interference shielding

With the rapid development of the electronics industry, smart wearable electronics and electromagnetic interference (EMI) shielding materials have attracted tremendous interest. However, it is still a great challenge to maintain stable performance after damage. Herein, we prepare a super-stretchable and self-healing hydrogel composite with exceptional EMI shielding performance by the in situ polymerization of the acrylamide (AAm) and N-acryloyl-11-aminoundecanoic acid (A-11) in the silver nanowires (AgNWs) aerogel with a cellular structure. Benefiting the continuous three-dimensional AgNWs network, the hydrogel composite has high electrical conductivity (83 S/cm), outstanding resistance-strain response of more than 800% tensile strain, and exceptional EMI effectiveness (SE) of 66 dB in X-band, capable of monitoring human motions as a wearable sensor. Moreover, the reversible hydrophobic association and hydrogen bonding interactions endow the hydrogel composite with excellent self-healing capability (EMI SE healing efficiency of 90%). The healed hydrogel composite can still serve as a sensor to respond rapidly and steadily to human motions. The super-stretchable and self-healing hydrogel composite holds great promise for smart wearable electronics and EMI shielding.

Single Solid Precursor-Derived Three-Dimensional Nanowire Networks of CuZn-Silicate for CO2 Hydrogenation to Methanol

Hydrogenation of CO2 to MeOH is one of the most promising technologies in mitigating the emissions of CO2 and tackling the challenge of climate change. In this work, we present a synthetic protocol for preparing a Cu–ZnO-based heterogeneous catalyst supported by siliceous nanowire networks from a single solid precursor with a tunable composition. The resulting Si–Cu–Zn catalysts were evaluated with the MeOH synthesis from the CO2 hydrogenation reaction operated at moderate conditions (30 barg and 200–280 °C). A specific MeOH yield of 402 mgMeOH·gCu–1·h–1 and a MeOH selectivity of 51% were obtained at 240 °C. Such a performance was attributed to several structural and compositional merits, granted through the attentively engineered synthetic procedures. Small Cu nanoparticle (NP) size was achieved and maintained by the high dispersion of Cu to the atomic level in the precatalyst and the incorporation of ZnO as a structural promoter. Moreover, the desirable Cu–ZnO synergistic effect can be further attained from the strong metal–support interaction (SMSI) between the Cu NPs and the partially reduced ZnO phase. Lastly, the robust siliceous nanowire networks provided decent spatial confinement to contain the growth of Cu NPs while offering high accessibility with the macroscopic porous morphology. The catalyst exhibited stable performance over a week’s long stability test while keeping its structural integrity intact. Overall, this study may offer an alternative design and synthesis strategy for the well-received Cu–ZnO system to approach its high performance in CO2 hydrogenation.

Strong ion interaction inducing ultrahigh activity of NiCoP nanowires for overall water splitting at large current density

The design and development of cheap and efficient electrocatalysts are particularly imperative for renewable energy, but still a challenge for overall water splitting (OWS). Herein, The NiCoP-10 g-125℃ with three-dimensional (3D) nanowire structures grown on nickel foam (NF) was successfully prepared by a novel molten salt method (MSM), serving as an excellent bifunctional electrocatalyst. The catalyst only needs minimal overpotential of 159 and 391 mV to gain the large current density of 400 mA cm−2 for HER and OER in 1 M KOH, respectively. Meanwhile, the alkaline electrolyzer assembled by two electrodes requires a cell voltage of 1.83 V to achieve 400 mA cm−2 for OWS and runs stably at 100 mA cm−2 for 100 h without apparent potential decay. Such impressive catalyticperformance is mainly attributed to the special molten salt synthesis method which provides a liquid environment with strong ions interaction. This special reaction condition contributes to forming 3D nanowire structures with the advantage of high metal loading, large specific surface area, fast charge transfer, and good mechanical strength. Therefore, this work can offer a new avenue for the synthesis of ultrahigh activity bifunctional electrocatalysts.

Novel Denitrification Fuel Cell for Energy Recovery of Nitrate-N and TN Removal Based on NH4+ Generation on a CNW@CF Cathode.

NO3- is an undesirable environmental pollutant that causes eutrophication in aquatic ecosystems, and its pollution is difficult to eliminate because it is easily converted into NH4+ instead of N2. Additionally, it is a high-energy substance. Herein, we propose a novel denitrification fuel cell to realize the chemical energy recovery of NO3- and simultaneous conversion of total nitrogen (TN) into N2 based on the outstanding ability of NH4+ generation on a three-dimensional copper nanowire (CNW)-modified copper foam (CF) cathode (CNW@CF). The basic steps are as follows: direct and highly selective reduction of NO3- to NH4+ rather than to N2 on the CNW@CF cathode, on which negative NO3- ions can be easily adsorbed due to their double-electron layer structure and active hydrogen ([H]) can be generated due to a large number of catalytic active sites exposed on CNWs. Then, NH4+ is selectively oxidized to N2 by the strong oxidation of chlorine free radicals (Cl•), which originate from the reaction of chlorine ions (Cl-) by photogenerated holes (h+) and hydroxyl radicals (OH•) under irradiation. Then, the electrons from the oxidation on the photoanode is transferred to the cathode to form a closed loop for external power generation. Owing to the continuous redox loop, NO3- completely reduces to N2, and the released chemical energy is converted into electrical energy. The results indicate that 99.9% of NO3- can be removed in 90 min, and the highest yield of electrical power density reaches 0.973 mW cm-2, of which the nitrate reduction rates on the CNW@CF cathode is 79 and 71 times higher than those on the Pt and CF cathodes, respectively. This study presents a novel and robust energy recycling concept for treating nitrate-rich wastewater.

Super-Stretchable and Self-Healing Hydrogel with Three-Dimensional Silver Nanowires Network for Wearable Sensor and Electromagnetic Interference Shielding

Super-Stretchable and Self-Healing Hydrogel with Three-Dimensional Silver Nanowires Network for Wearable Sensor and Electromagnetic Interference Shielding

Three-dimensional gold nanowires with high specific surface area for simultaneous detection of heavy metal ions.

Traditional detection methods to detect heavy metal ions are time-consuming, complicated, and expensive. Here, we developed a simple electroless plating method to prepare three-dimensional gold nanowire (Au NW) films with high specific surface area. In an aqueous plating bath, tetrachloroauric acid, 4-dimethylaminopyridine and formaldehyde are used as precursor, ligand, and reducing agent, respectively. An electrochemical sensor based on a Au NWs/SPE could be applied for simultaneous detection of lead (Pb(II)), arsenic (As(III)), and mercury (Hg(II)) ions. The detection limits of Pb(II), As(III), and Hg(II) are 2.6, 1.5, and 4.2 μg L-1, all lower than the permissible limits of the WHO for drinking water (the permissible level of Pb(II) and As(III) is 10.0 μg L-1, and the permissible level of Hg(II) is 6.0 μg L-1), respectively. This work presents a simple and novel method to prepare gold nanowires for quick detection of trace heavy metal ions.

Highly efficient removal of total nitrogen and dissolved organic compound in waste reverse osmosis concentrate mediated by chlorine radical on 3D Co3O4 nanowires anode

Reverse osmosis concentrate (ROC) from wastewater reclamation has posed significant disposal challenges due to its highly concentrated NH3-N, chloride ion and bio-refractory organics, and developing technologies for their removal are essential. Herein, we developed an efficient electrochemical system to remove total nitrogen and dissolved organic compound (DOC) simultaneously mediated by chlorine radical (Cl•), which is generated by activation of chloride ion existing in ROC on an inexpensive, three-dimensional Co3O4 nanowires. Results showed that the total nitrogen and total organic carbon removal were 98.2% and 56.9% in 60 min for synthetic ROC with 56 mg/L of NH3-N and 20 mg/L of DOC. The utilization of Co3O4 nanowires enhanced NH3-N degradation by 2.58 times compared with Co3O4 nanoplates, which were 1.69 and 17.5 times these of RuO2 and Pt. We found that structural Co3+/Co2+ acts as cyclic catalysis to produce Cl• via single-electron transfer, which convert NH3-N to N2 and lead to faster DOC degradation. This architecture provides abundant catalytic sites and sufficient accessibility of reactants. Small amount of nitrate generated by oxidation of NH3-N was further reduced to N2 on Pd-Cu/NF cathode. These findings provide new insights for utilization of waste Cl– and development of novel electrochemical system for ROC disposal.