Regulating adsorption ability toward polysulfides in a porous carbon/Cu_(3)P hybrid for an ultrastable high-temperature lithium-sulfur battery

Lithium-sulfur batteries(LSBs)can work at high temperatures,but they suffer from poor cycle life stability due to the“shuttle effect”of polysulfides.In this study,pollen-derived porous carbon/cuprous phosphide(PC/Cu_(3)P)hybrids were rationally synthesized using a one-step carbonization method using pollen as the source material,acting as the sulfur host for LSBs.In the hybrid,polar Cu_(3)P can markedly inhibit the“shuttle effect”by regulating the adsorption ability toward polysulfides,as confirmed by theoretical calculations and experimental tests.As an example,the camellia pollen porous carbon(CPC)/Cu_(3)P/S electrode shows a high capacity of 1205.6 mAh g^(−1) at 0.1 C,an ultralow capacity decay rate of 0.038%per cycle after 1000 cycles at 1 C,and a rather high initial Coulombic efficiency of 98.5%.The CPC/Cu_(3)P LSBs can work well at high temperatures,having a high capacity of 545.9 mAh g^(−1) at 1 C even at 150℃.The strategy of the PC/Cu_(3)P hybrid proposed in this study is expected to be an ideal cathode for ultrastable high-temperature LSBs.We believe that this strategy is universal and worthy of in-depth development for the next generation energy storage devices.

AB023.Ultrastable gold nanoparticles as a drug delivery system for ocular therapy

Background:Ocular therapy administrated by ophthalmic drops is advantageous thanks to its simplicity.However,efficiency of active molecules is limited when administered by this method.Indeed,more than 99.9%is discarded due to multiple factors including lacrimal drainage.Low retention time of drugs at the cornea leads to their poor penetration.Our hypothesis is that a drug delivery system based on gold nanoparticles should enhance the efficiency of the drugs.The main objective is to develop new methods to improve active molecules biodisponibility in ocular therapy thanks to a new drug delivery system implying gold nanoparticles.The specific objectives are:(I)to synthesize and characterize ultrastable gold nanoparticles,(II)to establish the drug encapsulation protocol,(III)to develop a separation method of free and encapsulated drugs to allow their quantification,(IV)to study the cytotoxicity of our gold nanoparticles.Methods:Ultrastable gold nanoparticles were synthesized by a new method and their ultrastability toward several harsh conditions was characterized.An encapsulation protocol was settled for several drugs.The separation of free and encapsulated drugs was performed with magnetic beads.The quantification of the encapsulated drugs was performed by HPLC.A MTS assay was performed on 3 corneal epithelial cell populations,exposed or unexposed to gold nanoparticles.Reconstructed corneas were prepared using the self-assembly method.A wound healing experience was performed on those corneas with or without nanoparticles.Results:Gold nanoparticles were synthesized and purified according to our new experimental conditions.They support harsh conditions as several cycles of freeze-drying,heating,salt exposition and ultracentrifugation.For the first time in literature,gold nanoparticle support autoclave sterilisation.The separation method involving magnetic beads was optimized to get rid of non-specific interactions.The encapsulation efficiency varies according to the active molecule.The MTS assay did not show diminution of the cellular viability when in presence of gold nanoparticles.Furthermore,gold nanoparticle exposition did not slow the wound healing of reconstructed corneas.Conclusions:Our new ultrastable gold nanoparticles can have a major impact in nanomedicine.They can support harsh conditions,as autoclave treatment,allowing their sterilisation for in vivo use.We showed that active molecules can be encapsulated in gold nanoparticles.In addition,they do not seem to cause any diminution of cellular viability.These data suggest the possible improvements in ocular therapy thanks to gold nanoparticles.

Mitigating the Reconstruction of Metal Sulfides for Ultrastable Oxygen Evolution at High Current Density

Metal sulfides are emerging highly active electrocatalysts for the oxygen evolution reaction(OER),but still suffer from the instability caused by their inevitable reconstruction,especially at industrial-level current density.Here,it is discovered that Fe-incorporated Ni3S2 nanowires can deliver extraordinary durability with an ultralow potential degradation rate of 0.006 mV/h in alkaline electrolytes made with fresh water and seawater at a benchmark of 500 mA cm^(-2) while meeting the industrial activity requirement for overpotential less than 300 mV(290 mV).Systematic experiments and theoretical simulations suggest that after forming the S-doped NiFeOOH shell to boost intrinsic activity,Fe incorporation effectivelymitigates the reconstruction of the Ni_(3)S_(2) nanowire core by restraining Ni oxidation and S dissolution,justifying the performance.This work highlights the significance of circumventing reconstruction and provides a strategy to explore practical chalcogenides-based OER electrocatalysts.

All-fiber-based ultrastable laser with long-term frequency stability of 1.1×10^(-14)

We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum chamber with a five-layer thermal shield,and a delicate two-stage active temperature stabilization,an optical power stabilization,and an RF power stabilization were applied in the system.A fractional frequency stability of better than 3.2×10^[-15]at 1 s averaging time and1.1×10^[-14]at 1000 s averaging time was achieved,which is the best long-term frequency stability of an all-fiber-based ultrastable laser observed to date.

光/蒸气协同构建交联多孔聚合物复合结构基超稳定高速阻变存储器

有机阻变存储器由两个电极及夹在其间的阻变聚合物层组成,具有湿法制备和功能可调的优点.然而,该类存储器还存在结构稳定性差、开关速度慢和图案化困难等问题.在本文中,我们利用光/蒸汽协同方法制备了一种具有交联多孔复合结构的非晶态聚合物薄膜,并将其作为阻变活性材料构建了一种具有高稳定性和高读取速度特征的存储阵列.所制备的聚合物二极管表现出非易失性的FLASH存储特性,具有高开关比、长维持时间以及快速信息写入(70 ns)和擦除(845 ns)等特征.令人印象深刻的是,该存储器件能够承受紫外辐射和极端温度等恶劣环境的考验.通过将存储阵列和特定传感器集成,构建了能模拟视觉/热感知和记忆功能的人造感知记忆系统,表明该系统在仿生神经形态电子领域具有巨大的应用潜力.该工作为制备具有高稳定性和高读取速度特征的聚合物存储阵列提供了一种可靠的策略.

Transparent glassy composites incorporating lead-free anti-perovskite halide nanocrystals enable tunable emission and ultrastable X-ray imaging

Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A=alkali metal;M=transition metal;X=Cl,Br,I),a class of electron-inverted perovskite derivatives,exhibit robust structural and photophysical stability.Here,we design and prepare a lead-free[MnBr_(4)]BrCs_(3) anti-perovskite nanocrystal(NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 Ip mm^(-1).Due to the unique crystal structure and the protection of the glass matrix,the Cs_(3)MnBr_(5) NC-embedded glass exhibits excellent X-ray irradiation stability,thermal stability,and water resistance.These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite.This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.

Ultrastable MOF-based foams for versatile applications

Metal-organic frameworks(MOFs)are attractive for promising applications but plagued by difficult recovery and deployment due to their intrinsic nano/micro powder nature.Although significant efforts have been made to develop separable solid matrixes for MOF supporting,the poor loading stability and durability of MOFs still challenge their engineering applications.Here,we present a facile and effective approach to fabricate MOF-based melamine foams(MFs)(denoted as MOFiths)with ultrahigh loading stability and operation stability,easy separation,and high-efficient performance for versatile robust applications.By adopting our approach,numbers of typical fragile MOFs characterized with wide ranges of particle size(from~nm to~μm)can be precisely incorporated into MFs with controllable loading ratios(up to~1,600%).Particularly,the produced MOFiths show excellent capacities for the highly effective and durable water purifications and acetalization reactions.100%of organic pollutants can be rapidly destructed within 10 min by MOFiths initiated Fenton or catalytic ozonation processes under five successive cycles while the maximum adsorption capacity of MOFiths toward Pb(II),Cd(II),and Cu(II)reaches to 422,222,and 105 mg·g^(-1),respectively.This study provides a critical solution to substantially facilitate the engineering applications of MOFs for long-term use in practice.

An Ultrastable π-π Stacked Porous Organic Molecular Framework as a Crystalline Sponge for Rapid Molecular Structure Determination

The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.

Probing the formation of ultrastable metallic glass from structural heterogeneity

Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions generate an SMG is an emerging challenge.Herein,amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr_(50)Cu_(50),Zr_(50)Cu_(44.5)Al_(5.5)and Zr_(50)Cu_(41.5)Al_(5.5)Mo_(3) thin film metallic glasses(TFMGs)that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only variable.The transition in stability from bulkto SMG-like behavior resides in the change of relaxation mechanism as the deposition rate is decreased.The formation of SMGs is directly linked with the degree of structural heterogeneity,whereby MGs with greater heterogeneity have a higher potential to form SMGs with more significant enhancement in stability.Slower deposition rates,however,are required to yield the more homogenous structure and lower energy state underlying the ultrastability.Ultrastability is closely linked with the geometric shape and distribution of loosely packed phases,whereby SMGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in stability.This work not only provides direct evidence of the structure of SMGs,but also opens new horizons for the design of SMGs.

Multi-cavity-stabilized ultrastable laser

We demonstrate a proposal for making an ultrastable laser referenced to a multi-cavity, enabling a lower thermal noise limit due to the averaging effect. In comparison with a single-cavity system, relative frequency instability of the synthesized laser can be improved by a factor of the square root of the cavity number. We perform an experiment to simulate a two-cavity system with two independent ultrastable lasers. Experimental results show that the relative frequency instability（Allan deviation） of the synthesized laser is 5 × 10;, improved by a factor of √2 from a single-cavity-stabilized laser.