Ordered Macroporous MoS_(2)-Carbon Composite with Fast and Robust Sodium Storage Properties to Solve the Issue of Kinetics Mismatch of Sodium-Ion Capacitors

Metal-ion capacitors(including Li^(+),Na^(+),and K^(+))effectively combine a battery negative electrode capable of reversibly intercalating metal cations,together with an electrical double-layer positive electrode.However,such novel cell design has a birth defect,namely kinetics mismatch between sluggish negative electrode and fast positive electrode,thus limiting the energy-power performance.Herein,we design a MoS_(2)-carbon composite anode with the ordered macroporous architecture and interlayer-expanded feature,exhibiting the fast and reversible Na^(+)redox processes.This kinetically favored anode is coupled with a homemade activated carbon cathode that allows for the excellent electrochemical performance of sodiumion capacitor with respect to large specific capacity,high-rate capability,and robust cycling.Through quantification of the potential swings of anode and cathode via a three-electrode Swagelok cell,we for the first time observe the abnormal variation law of potential swings and thus directly providing the evidence that the kinetics gap has been filled up by this kinetically favored anode.Our results represent a crucial step toward understanding the key issues of kinetics mismatch for hybrid cell,thus propelling the development of design of kinetically favored anode materials for high-performance metalion capacitors.

Ultralight aerogel sphere composed of nanocellulose-derived carbon nanofiber and graphene for excellent electromagnetic wave absorption

A novel type of three-dimensional ultralight aerogel sphere,consisting of one-dimensional nanocellulose-derived carbon fibers and two-dimensional graphene layers,was prepared based on a developed drop-freeze-drying followed by carbonization approach.The nanofibrous carbon efficiently prevents the agglomeration of the graphene layers,which,in turn,reduces the shrinkage and maintains the structural stability of the hybrid carbon aerogel spheres.Consequently,the aerogel spheres showing an ultralow-density of 2.8 mg/cm^(3) and a porosity of 99.98%accomplish the tunable dielectric property and electromagnetic wave(EMW)absorption performance.The high-efficiency utilization of biomass-derived fibrous nanocarbon,graphene,the porous structure of the hybrid aerogel spheres leads to the excellent EMW absorption performance.The aerogel spheres display an effective absorption bandwidth of 6.16 GHz and a minimum reflection loss of−70.44 dB even at a filler loading of merely 3 wt.%,significantly outperforming that of other biomass-derived carbon-based EMW absorbing materials.This work offers a feasible,facile,scalable approach for fabricating high-performance and sustainable biomass-based aerogels,suggesting a tremendous application potential in EMW absorption and aerospace.

DNA methylation drives a new path in gastric cancer early detection:Current impact and prospects

Gastric cancer(GC)is one of the most common and deadly cancers worldwide.Early detection offers the best chance for curative treatment and reducing its mortality.However,the optimal population-based early screening for GC remains unmet.Aberrant DNA methylation occurs in the early stage of GC,exhibiting cancer-specific genetic and epigenetic changes,and can be detected in the media such as blood,gastric juice,and feces,constituting a valuable biomarker for cancer early detection.Furthermore,DNA methylation is a stable epigenetic alteration,and many innovative methods have been developed to quantify it rapidly and accurately.Nonetheless,large-scale clinical validation of DNA methylation serving as tumor biomarkers is still lacking,precluding their implementation in clinical practice.In conclusion,after a critical analysis of the recent existing literature,we summarized the evolving roles of DNA methylation during GC occurrence,expounded the newly discovered noninvasive DNA methylation biomarkers for early detection of GC,and discussed its challenges and prospects in clinical applications.

Research on Electromagnetic Wave Absorption Based on Electrospinning Technology

At present,in order to overcome electromagnetic interference and prevent electromagnetic harm,the research of new and efficient electromagnetic wave absorbing materials has become the research focus in the field of materials science.The one-dimensional structure can promote the impedance matching and attenuation characteristics of the absorbing materials.Electrospinning,as an effective method to prepare nanofibers with high length-diameter ratio,has been widely concerned because it is suitable for struc-tural design of various materials.In this paper,the research progress and absorption properties of nano-fiber materials prepared by electrospinning combined with different processes are introduced.

Scalable synthesis of macroscopic porous carbon sheet anode for potassium-ion capacitor

Carbon materials hold the great promise for application in energy storage devices owing to their low cost, high thermal/chemical stability, and high electrical conductivity. However, it remains challenging to synthesize high-performance carbon electrodes in a simple, scalable and sustainable way. Here, we report a facile method for scalable synthesis of porous carbon anode by using cheap and easily accessible zeolitic imidazolate framework-8 as a template and polyvinylpyrrolidone as an additional carbon source. The obtained porous carbon shows the macroscopic sheet-like morphology, which has the highly disordered structure, expanded interlayer spacing, abundant pore structure, and nitrogen doping properties. This porous carbon anode is demonstrated to have the excellent K^(+) charge storage properties in specific capacity, rate capability, and cycling stability. A potassium-ion capacitor assembled by using this porous carbon as the anode, delivers a maximum energy density of 85.12 Wh/kg and power density of 11860 W/kg as well as long cycle life exceeding 3000 cycles. This represents a critical advance in the design of low cost and scalable carbon material for applications in energy storage devices.

Observation of “Outlaw” Dual Aromaticity in Unexpectedly Stable Open-Shell Metal Clusters Caused by Near-Degenerate Molecular Orbital Coupling

The Hückel’s rule,Baird’s rule,and electronic shell closure model are classical and well-established concepts in chemistry,which have long been employed in rationalizing the aromaticity/antiaromaticity of organic species and stability of inorganic clusters.Thus,the observation of unique species featuring properties out of the fundamental frameworks of these rules is challenging but significant and helps in drawing a complete picture of fascinating concepts in chemistry.

In vitro characterization of a nitro-forming oxygenase involved in 3-(trans-2’-aminocyclopropyl)alanine biosynthesis

In vitro characterization experiments revealed the formations of 3-(trans-2’-aminocyclopropyl)alanine((3-Acp)Ala)and 3-(trans-2’-nitrocyclopropyl)alanine((3-Ncp)Ala)are originated via two homologous proteins,BelK and HrmI,which regioselectively catalyze the N𝜀-oxygenation of l-lysine.The two enzymes belong to the emerg-ing heme-oxygenase-like diiron oxidase and oxygenase(HDO)superfamily and the catalytic center of BelK is validated by homology modeling and site-directed mutations.Based on the in vitro characterization,the biosyn-thetic pathways of(3-Acp)Ala and(3-Ncp)Ala are proposed.

Progress and perspectives on two-dimensional silicon anodes for lithium-ion batteries

Silicon(Si)anodes with extremely high theoretical capacities are considered indispensable for next-generation high-energy lithium-ion batteries(LIBs).However,several intractable problems,including pulverization,poor electrical contact,and continuous side reactions caused by the large volume change of Si during lithia-tion/delithiation,lead to a short cycle life and poor rate capability,thus hindering the commercial use of Si anodes in LIBs.Two-dimensional(2D)Si with a unique graphene-like structure has a short ion diffusion path-way,small volume change during lithiation,and efficient redox site utilization,making it more promising than bulk Si or Si with other versatile structures for use in LIBs.Theoretical analysis demonstrated that the low energy barrier on the surface of 2D Si accelerates the transport of Li+.However,the issues surrounding 2D Si,includ-ing the tedious and user-unfriendly synthesis,ease of restacking,and atmospheric sensitivity,limit its practical applications,which are discussed in this review.Furthermore,possible solutions to these remaining challenges and new directions are provided,with the aim of designing practical and high-performance 2D Si anodes for next-generation LIBs.

Shining light on transition metal sulfides:New choices as highly efficient antibacterial agents

Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to fight with the bacteria variation.The emergence of super-bacteria will be an intractable environmental and health hazard in the future unless novel bactericidal weapons are mounted.Consequently,it is critical to develop viable antibacterial approaches to sustain the prosperous development of human society.Recent researches indicate that transition metal sulfides(TMSs)represent prominent bactericidal application potential owing to the meritorious antibacterial performance,acceptable biocompatibility,high solar energy utilization efficiency,and excellent photo-to-thermal conversion characteristics,and thus,a comprehensive review on the recent advances in this area would be beneficial for the future development.In this review article,we start with the antibacterial mechanisms of TMSs to provide a preliminary understanding.Thereafter,the state-of-the-art research progresses on the strategies for TMSs materials engineering so as to promote their antibacterial properties are systematically surveyed and summarized,followed by a summary of the practical application scenarios of TMSs-based antibacterial platforms.Finally,based on the thorough survey and analysis,we emphasize the challenges and future development trends in this area.

A high-performance potassium-ion capacitor based on a porous carbon cathode originated from the Aldol reaction product

Potassium-ion capacitors(KICs) emerge as a promising substitute for the well-developed lithium-ion capacitors(LICs),however,the energy density of KICs is below expectations because of lacking a suitable electrical double-layer positive electrode.Using chemical activation of the Aldol reaction product of acetone with KOH,we synthesized a porous ca rbon with a Brunauer-Emmett-Teller surface area of up to 2947 m2/g and a narrow pore size distribution ranging from 1 nm to 3 nm.Half-cell(versus potassium metal) test demonstrates that this porous carbon has high capacitive performance in K+ based organic electrolytes.Furthermore,a novel KIC fabricated by this porous carbon as the cathode,yields high values of energy density and power density.The processes used to make this porous carbon are readily low-cost to fabricate metal-ion capacitors.

Advanced sodium-ion capacitor based on antimony-carbon composite anode

Alloy-type materials with the characteristics of high theoretical capacity,low sodiation/desodiation potential,and good conductivity are considered as one of the most promising anodes for sodium-ion batteries or capacitors.However,the large volume change during the sodiation leads to poor cyclability and slow kinetics,thus presenting the main issue impeding the practical application.Herein,we propose a facile wet chemistry and pyrolysis method to synthesize Sb-carbon composite that Sb nanoparticles or single atoms are confined and/or dispersed in the wrinkled carbon framework with high nitrogen content.This unique architecture of Sb-carbon composite increases atomic interface contact/interaction with Na~+,facilitating ion diffusion and alleviating the volume change of Sb during the charge/discharge process.Half-cell test shows that Sb-carbon composite exhibits a high-rate capability and stable cycling life.Furthermore,sodium-ion capacitors fabricated by employing Sb-carbon composite as anode and home-made active carbon as cathode,deliver both high-energy density of 157 Wh·kg^(-1)and high-power density of 25 kW·kg^(-1)as well as excellent cycling performance exceeding 4000 cycles.

高储锂性能的氮、磷共掺杂分级多孔炭纳米球用于高比能锂离子电容器

锂离子电容器通常由一个电池型负极和一个电容型多孔炭正极组成,可输出比传统双电层电容器高两倍的能量密度,但是在高倍率条件下其能量密度低、循环寿命短,因而其广泛应用受到阻碍.本文通过模板法合成了一种结构高度无序、氮/磷共掺杂的分级介孔炭纳米球.这种分级多孔结构有利于锂离子的快速迁移,且高度无序的结构和高杂原子含量为锂离子电荷存储提供了丰富的活性位点.电化学测试表明,该炭纳米球负极具有较高比容量(在0.1 A g^(-1)时,为1108.6 mA h g^(-1)),优异的倍率性能(在8 A g^(-1)时,为276.5 mA h g^(-1)),以及良好的循环稳定性(1000次循环后仍保持85%的容量).以该分级多孔纳米球为负极,自制活性炭为正极所组装的锂离子电容器具有较高的能量密度(103 W h kg^(-1))、功率密度(44,630 W kg^(-1))以及长循环寿命(>10,000圈).该工作揭示了如何通过在纳米/原子尺度上调控炭材料微结构来提高电化学性能的方法,为设计高性能的储能设备提供了新策略.

Organic ligand mediated evolution from superalkalis to superatomic molecules and nanowires

Superatoms are considered as promising building blocks for customizing superatomic molecules and cluster-assembly nanomaterials due to their tunable electronic structures and functionalities.Electron counting rules,which mainly adjust the shell-filling of clusters,are classical strategies in designing superatoms.Here,by employing the density functional theory(DFT)calculations,we proved that the 1,4-phenylene diisocyanide(CNC_(6)H_(4)NC)ligand could dramatically reduce the adiabatic ionization potentials(AlPs)of the aluminum-based clusters,which have 39,40,and 41 valence electrons,respectively,to give rise to superalkali species without changing their shell-filling.Moreover,the rigid structure of the ligand can be used as a bridge firmly linking the same or different aluminum-based clusters to form superatomic molecules and nanowires.In particular,the bridging process was observed to enhance their nonlinear optical(NLO)responses,which can be further promoted by the oriented external electric field(OEEF).Also,the stable cluster-assembly XAl_(12)(CNC_(6)H_(4)NC)(X=Al,C,and P)nanowires were constructed,which exhibit strong absorption in the visible light region.These findings not only suggest an effective ligand-field strategy in superatom design but also unveil the geometrical and electronic evolution from the CNC_(6)H_(4)NC-based superatoms to superatomic molecules and nanomaterials.