Nano Materials Science最新文献

All-solid-state batteries (ASSBs) are a class of safer and higher-energy-density materials compared to conventional devices, from which solid-state electrolytes (SSEs) are their essential components. To date, investigations to search for high ion-conducting solid-state electrolytes have attracted broad concern. However, obtaining SSEs with high ionic conductivity is challenging due to the complex structural information and the less-explored structure-performance relationship. To provide a solution to these challenges, developing a database containing typical SSEs from available experimental reports would be a new avenue to understand the structure-performance relationships and find out new design guidelines for reasonable SSEs. Herein, a dynamic experimental database containing >600 materials was developed in a wide range of temperatures (132.40–1261.60 ​K), including mono- and divalent cations (e.g., Li⁺, Na⁺, K⁺, Ag⁺, Ca²⁺, Mg²⁺, and Zn²⁺) and various types of anions (e.g., halide, hydride, sulfide, and oxide). Data-mining was conducted to explore the relationships among different variates (e.g., transport ion, composition, activation energy, and conductivity). Overall, we expect that this database can provide essential guidelines for the design and development of high-performance SSEs in ASSB applications. This database is dynamically updated, which can be accessed via our open-source online system.

The trade-off between efficiency and stability has limited the application of TiO₂ as a catalyst due to its poor surface reactivity. Here, we present a modification of a TiO₂ layer with highly stable Sub-5 nm Fe₂O₃ nanoparticles (NP) by modulating its structure-surface reactivity relationship to attain efficiency-stability balance via a voltage-assisted oxidation approach. In situ simultaneous oxidation of the Ti substrate and Fe precursor using high-energy plasma driven by high voltage resulted in uniform distribution of Fe₂O₃ NP embedded within porous TiO₂ layer. Comprehensive surface characterizations with density functional theory demonstrated an improved electronic transition in TiO₂ due to the presence of surface defects from reactive oxygen species and possible charge transfer from Ti to Fe; it also unexpectedly increased the active site in the TiO₂ layer due to uncoordinated electrons in Sub-5 nm Fe₂O₃ NP/TiO₂ catalyst, thereby enhancing the adsorption of chemical functional groups on the catalyst. This unique embedded structure exhibited remarkable improvement in reducing 4-nitrophenol to 4-aminophenol, achieving approximately 99% efficiency in 20 ​min without stability decay after 20 consecutive cycles, outperforming previously reported TiO₂-based catalysts. This finding proposes a modified-electrochemical strategy enabling facile construction of TiO₂ with nanoscale oxides extandable to other metal oxide systems.

Carbon nano additives (CNAs) are critical to achieving the unique properties of functionalized composites, however, controlling the dispersion of CNAs in material matrix is always a challenging task. In this study, a simple atomization approach was successfully developed to promote the dispersion efficiency of graphene nanoplatelets (GNPs) in cement composites. This atomization approach can be integrated with the direct, indirect and combined ultrasonic stirrings in a homemade automatic stirring-atomization device. Mechanical and microstructure tests were performed on hardened cement pastes blended with GNPs in different stirring and mixing approaches. Results show that the direct ultrasonic stirrings enabled more homogeneous dispersions of GNP particles with a smaller size for a longer duration. The atomized droplets with the mean size of ∼100 ​μm largely mitigated GNPs’ agglomerations. Monolayer GNPs were observed in the cement matrix with the strength gain by up to 54%, and the total porosity decrease by 21% in 0.3 ​wt% GNPs dosage. The greatly enhanced dispersion efficiency of GNPs in cement also raised the cement hydration. This work provides an effective and manpower saving technique toward dispersing CNAs in engineering materials with great industrialization prospects.

Grain boundaries (GBs) play a crucial role on the structural stability and mechanical properties of Cu and its alloys. In this work, molecular dynamics (MD) simulations are employed to study the effects of Fe solutes on the formation energy, excess volume, dislocations and melting behaviors of GBs in CuFe alloys. It is illustrated that Fe solute affects the structural stability of Cu GBs substantially, the formation energy of GBs is reduced, but the thickness and melting point of GBs are increased, that is, the structural stability of Cu GBs is significantly improved owing to the Fe solutes. A strong scaling law exists between the formation energy, excess volume, thickness and melting point of GBs. Therefore, Fe solid solute plays an important role in the characteristics of GBs in bi-crystal Cu.

Recently, poly(ethylene oxide) (PEO)-based solid polymer electrolytes have been attracting great attention, and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries. In this article, a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries. The PEO-based composite electrolyte is fabricated by hot-pressing PEO, LiTFSI and Ti₃C₂T_x MXene nanosheets into glass fiber cloth (GFC). The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties, good electrochemical stability, and high lithium-ion migration number, which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene. Such as, the GFC@PEO-1 wt% MXene electrolyte shows a high tensile strength of 43.43 ​MPa and an impressive Young's modulus of 496 ​MPa, which are increased by 1205% and 6048% over those of PEO. Meanwhile, the ionic conductivity of GFC@PEO-1 wt% MXene at 60 ​°C reaches 5.01 ​× ​10⁻² ​S ​m⁻¹, which is increased by around 200% compared with that of GFC@PEO electrolyte. In addition, the Li/Li symmetric battery based on GFC@PEO-1 wt% MXene electrolyte shows an excellent cycling stability over 800 ​h (0.3 ​mA ​cm⁻², 0.3 ​mAh cm⁻²), which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt% MXene electrolyte with Li anode. Furthermore, the solid-state Li/LiFePO₄ battery with GFC@PEO-1 wt% MXene as electrolyte demonstrates a high capacity of 110.2–166.1 ​mAh g⁻¹ in a wide temperature range of 25–60 ​°C, and an excellent capacity retention rate. The developed sandwich structured GFC@PEO-1 wt% MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

This work presents the development of hierarchical niobium pentoxide (Nb₂O₅)-based composite nanofiber membranes for integrated adsorption and photocatalytic degradation of methylene blue (MB) pollutants from aqueous solutions. The Nb₂O₅ nanorods were vertically grown using a hydrothermal process on a base electrospun nanofibrous membrane made of polyacrylonitrile/polyvinylidene fluoride/ammonium niobate (V) oxalate hydrate (Nb₂O₅@PAN/PVDF/ANO). They were characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) analysis, and Fourier transform infrared (FTIR) spectroscopy. These composite nanofibers possessed a narrow optical bandgap energy of 3.31 ​eV and demonstrated an MB degradation efficiency of 96 ​% after 480 ​min contact time. The pseudo-first-order kinetic study was also conducted, in which Nb₂O₅@PAN/PVDF/ANO nanofibers have kinetic constant values of 1.29 ​× ​10⁻² ​min⁻¹ and 0.30 ​× ​10⁻² ​min⁻¹ for adsorption and photocatalytic degradation of MB aqueous solutions, respectively. These values are 17.7 and 7.8 times greater than those of PAN/PVDF/ANO nanofibers without Nb₂O₅ nanostructures. Besides their outstanding photocatalytic performance, the developed membrane materials exhibit advantageous characteristics in recycling, which subsequently widen their practical use in environmental remediation applications.

High-performance flexible pressure sensors provide comprehensive tactile perception and are applied in human activity monitoring, soft robotics, medical treatment, and human-computer interface. However, these flexible pressure sensors require extensive nano-architectural design and complicated manufacturing and are time-consuming. Herein, a highly sensitive, flexible piezoresistive tactile sensor is designed and fabricated, consisting of three main parts: the randomly distributed microstructure on T-ZnOw/PDMS film as a top substrate, multilayer Ti₃C₂-MXene film as an intermediate conductive filler, and the few-layer Ti₃C₂-MXene nanosheet-based interdigital electrodes as the bottom substrate. The MXene-based piezoresistive sensor with randomly distributed microstructure exhibits a high sensitivity over a broad pressure range (less than 10 ​kPa for 175 ​kPa⁻¹) and possesses an out-standing permanence of up to 5000 cycles. Moreover, a 16-pixel sensor array is designed, and its potential applications in visualizing pressure distribution and an example of tactile feedback are demonstrated. This fully sprayed MXene-based pressure sensor, with high sensitivity and excellent durability, can be widely used in, electronic skin, intelligent robots, and many other emerging technologies.

Nanorubber/epoxy composites containing 0, 2, 6 and 10 ​wt% nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8 ​× ​10⁻⁴ s⁻¹ to ∼2 ​× ​10⁴ s⁻¹. Unexpectedly, their strain rate sensitivity and strain hardening index increase with increasing nanorubber content. Potential mechanisms are proposed based on numerical simulations using a unit cell model. An increase in the strain rate sensitivity with increasing nanorubber content results from the fact that the nanorubber becomes less incompressible at high strain, generating a higher hydro-static pressure. Adiabatic shear localization starts to occur in the epoxy under a strain rate of 22,000 s⁻¹ when the strain exceeds 0.35. The presence of nanorubber in the epoxy reduces adiabatic shear localization by preventing it from propagating.

Artificial synapse inspired by the biological brain has great potential in the field of neuromorphic computing and artificial intelligence. The memristor is an ideal artificial synaptic device with fast operation and good tolerance. Here, we have prepared a memristor device with Au/CsPbBr₃/ITO structure. The memristor device exhibits resistance switching behavior, the high and low resistance states no obvious decline after 400 switching times. The memristor device is stimulated by voltage pulses to simulate biological synaptic plasticity, such as long-term potentiation, long-term depression, pair-pulse facilitation, short-term depression, and short-term potentiation. The transformation from short-term memory to long-term memory is achieved by changing the stimulation frequency. In addition, a convolutional neural network was constructed to train/recognize MNIST handwritten data sets; a distinguished recognition accuracy of ∼96.7% on the digital image was obtained in 100 epochs, which is more accurate than other memristor-based neural networks. These results show that the memristor device based on CsPbBr₃ has immense potential in the neuromorphic computing system.

Solar steam generation (SSG) is widely regarded as one of the most sustainable technologies for seawater desalination. However, salt fouling severely compromises the evaporation performance and lifetime of evaporators, limiting their practical applications. Herein, we propose a hierarchical salt-rejection (HSR) strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate, even in high-salinity brine. The salt diffusion process is segmented into three steps—insulation, branching diffusion, and arterial transport—that significantly enhance the salt-resistance properties of the evaporator. Moreover, the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate. Consequently, a high evaporation rate of 2.84 ​kg ​m⁻² ​h⁻¹, stable evaporation for 7 days cyclic tests in 20 ​wt% NaCl solution, and continuous operation for 170 ​h in natural seawater under 1 sun illumination were achieved. Compared with control evaporators, the HSR evaporator exhibited a >54% enhancement in total water evaporation mass during 24 ​h continuous evaporation in 20 ​wt% salt water. Furthermore, a water collection device equipped with the HSR evaporator realized a high water purification rate (1.1 ​kg ​m⁻² ​h⁻¹), highlighting its potential for agricultural applications.