Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

Polar promotors have been proven effective in catalyzing the polysulfide(PS)reduction reaction(PSRR)process in lithium-sulfur(Li-S)batteries.However,the promotor surface tends to be poisoned due to the accumulation of insoluble discharging products of lithium disulfide(Li_(2)S_(2))and lithium sulfide(Li_(2)S)during Li-S battery operation.Herein,we investigate the detailed PSRR mechanism on the surface of manganese sulfides(MnS)as a representative promoter by performing in-situ Raman mapping measurements.The catalytic ability of MnS enables thorough electrochemical reduction of PSs to Li_(2)S_(2) and Li_(2)S on the MnS surface.The generated Li_(2)S_(2) and Li_(2)S then adsorb the dissolved PSs via chemical reactions among sulfur species during the subsequent PSRR process.This phenomenon mitigates promotor poisoning and continuously improves the reversible capacity.Consequently,the assembled Li-S cell demonstrates excellent electrochemical performance after introducing a conductive interlayer containing a thin piece of carbon nanotube film and MnS promotors.

Erratum to:Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

Erratum to Nano Research,2024,17(4):2712-2718 https://doi.org/10.1007/s12274-023-6129-5 The affiliation of the author,Wenhui Duan,is“2 Department of Physics,Tsinghua University,Beijing 100084,China”,instead of“1 Tsinghua-Foxconn Nanotechnology Research Center,Tsinghua University,Beijing 100084,China;2 Department of Physics,Tsinghua University,Beijing 100084,China”.And the affiliation of the author,Wenhui Duan,in the online version and the ESM file of this paper has been corrected.

Fano resonance boosted cascaded optical field enhancement in a plasmonic nanoparticle-in-cavity nanoantenna array and its SERS application

Cascaded optical field enhancement(CFE)can be realized in some specially designed multiscale plasmonic nanostructures,in which the generation of extremely strong fields at nanoscale volume is crucial for many applications,for example,surface-enhanced Raman spectroscopy(SERS).In this paper,we propose a strategy for realizing a high-quality plasmonic nanoparticle-in-cavity(PIC)nanoantenna array,in which strong coupling between a nanoparticle(NP)dark mode with a high-order nanocavity bright mode can produce strong Fano resonance at the target wavelength.The Fano resonance can effectively boost the CFE in a PIC.A cost-effective and reliable nanofabrication method is developed using room temperature nanoimprinting lithography to manufacture high-quality PIC arrays.This technique guarantees the generation of only one gold NP at the bottom of each nanocavity,which is crucial for the generation of the expected CFE.To demonstrate the performance and application of the PIC array,the PIC array is employed as an active SERS substrate for detecting 4-aminothiophenol molecules.An experimental SERS enhancement factor of 2×10^(7) is obtained,which verifies the field enhancement and the potential of this device.

High temperature performance of coaxial h-BN/CNT wires above 1,000 ℃:Thermionic electron emission and thermally activated conductivity

The development of wires and cables that can tolerate extremely high temperatures will be very important for probing extreme environments, such as in solar exploration, fire disasters, high-temperature materials processing, aeronautics and astronautics. In this paper, a lightweight high-temperature coaxial h-boron nitride (BN)/carbon nanotube (CNT) wire is synthesized by the chemical vapor deposition (CVD) epitaxial growth of h-BN on CNT yarn. The epitaxially grown h-BN acts as both an insulating material and a jacket that protects against oxidation. It has been shown that the thermionic electron emission (1,200 K) and thermally activated conductivity (1,000 K) are two principal mechanisms for insulation failure of h-BN at high temperatures. The thermionic emission of h-BN can provide the work function of h-BN, which ranges from 4.22 to 4.61 eV in the temperature range of 1,306-1,787 K. The change in the resistivity of h-BN with temperature follows the ohmic conduction model of an insulator, and it can provide the “electron activation energy”(the energy from the Fermi level to the conduction band of h-BN), which ranges from 2.79 to 3.08 eV, corresponding to a band gap for h-BN ranging from 5.6 to 6.2 eV. However, since the leakage current is very small, both phenomena have no obvious influence on the signal transmission at the working temperature. This lightweight coaxial h-BN/CNT wire can tolerate 1,200 ℃ in air and can transmit electrical signals as normal. It is hoped that this lightweight high-temperature wire will open up new possibilities for a wide range of applications in extreme high-temperature conditions.

True-color real-time imaging and spectroscopy of carbon nanotubes on substrates using enhanced Rayleigh scattering

白光照亮的围单人赛的碳 nanotubes (SWCNT ) 应该由于散布的回声瑞利显得有颜色。然而，底层上的 SWCNT 的真彩成像没被报导，因为 SWCNT 和散布的强壮的底层的极其低的散布紧张。这里，我们证明散布的瑞利能被接口偶极子改进效果极大地提高。底层上的因而丰富多彩的 SWCNT 能被宽地 supercontinuum 激光照明直接在一台光显微镜下面想象，它便于单个 SWCNT 的高产量 chirality 赋值。这条途径，称为的瑞利成像显微镜学，没被限制为 SWCNT，但是对许多 nanomaterials 广泛地适用，它使丰富多彩的 nanoworld 能在光显微镜下面被探索。

In Situ TEM Observation of the Gasification and Growth of Carbon Nanotubes Using Iron Catalysts

We report the in situ transmission electron microscope (TEM) observation of the catalytic gasification and growth of carbon nanotubes (CNTs). It was found that iron catalysts can consume the CNTs when pumping out the precursor gas, acetylene, at the growth temperature, and reinitiate the growth when acetylene is re-introduced. The switching between gasification and growth of CNTs can be repeated many times with the same catalyst. To understand the phenomenon, thermogravimetric analysis (TGA) coupled with mass spectroscopy was used to study the mechanism involved. It was shown that the residual water molecules in the growth chamber of the TEM react with and remove carbon atoms of CNTs as carbon monoxide vapor under the action of the catalyst, when the precursor gas is pumped out. This result contributes to a better understanding of the water-assisted and oxygen-assisted synthesis of CNT arrays, and provides useful clues on how to extend the lifetime and improve the activity of the catalysts.

Interface dipole enhancement effect and enhanced Rayleigh scattering

一纳米或亚纳米的光效果包围象围单人赛的碳 nanotubes (SWCNT ) 那样的单个 nanomaterials 的压缩分子的界面的层理论上并且试验性地被学习了。当由光照亮了时，这界面的层作为一个光偶极子格子表现并且贡献在附近的原子，分子，或 nanomaterials 上提高本地地的一块即时近的地，它可以接着导致提高的瑞利散布，散布的拉曼，和荧光。这接口偶极子的理论提高了效果(IDEE ) 预言那在 nanomaterials 和界面的层的飞机之间的更小的距离，或到包围媒介的界面的层的绝缘的常数的更大的比率，将导致一个更大的领域改进因素。这预言被 SWCNT 以及在逐渐地控告的 SWCNT 散布的 situ 瑞利散布的提高的瑞利的几实现进一步试验性地验证。接口偶极子提高了散布的瑞利不仅启用真彩 nanomaterials 的即时成像，而且提供一个有效工具凝视进微妙的界面的现象。

Bidirectional micro-actuators based on eccentric coaxial composite oxide nanofiber

It is of great importance to develop new micro-actuators with high performance by optimizing the structures and materials.Here we develop a VO2/AI2O3/CNT eccentric coaxial nanofiber,which can be potentially applied as a micro-actuator.The specific eccentric coaxial structure was efficiently fabricated by conventional thin film deposition methodology with individual CNT templet.Activated by thermal and photothermal stimuli,the as-developed actuator delivers a bidirectional actuation behavior with large amplitudes and an ultra-fast response,〜2.5 mS.A tweezer can be further made by assembling two such nanofibers symmetrically onto a tungsten probe.Clamping and unclamping can be realized by laser stimulus.More experimental and simulation investigations indicated that the actuation behaviors could be attributed to the nanostructured eccentric coaxial geometry,the thermal coefficient mismatch between layers and the fast phase transition of V02.The micro-actuators will have potentials in micro manipulators,nanoscaled switches,remote controls and other autonomous systems.Furthermore,a large variety of coaxial and eccentric coaxial nanofibers with various functions can also be developed,giving the as-developed methodology more opportunities.

Scanning electron microscopy imaging of single-walled carbon nanotubes on substrates

Scanning electron microscopy （SEM） plays an indispensable role in nanoscience and nanotechnology because of its high efficiency and high spatial resolution in characterizing nanomaterials. Recent progress indicates that the contrast arising from different conductivities or bandgaps can be observed in SEM images if single-walled carbon nanotubes （SWCNTs） are placed on a substrate. In this study, we use SWCNTs on different substrates as model systems to perform SEM imaging of nanomaterials. Substantial SEM observations are conducted at both high and low acceleration voltages, leading to a comprehensive understanding of the effects of the imaging parameters and substrates on the material and surface-charge signals, as well as the SEM imaging. This unified picture of SEM imaging not only furthers our understanding of SEM images of SWCNTs on a variety of substrates but also provides a basis for developing new imaging recipes for other important nanomaterials used in nanoelectronics and nanophotonics.